A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.
Molecules which contain an atom or a group of atoms exhibiting an unpaired electron spin that can be detected by electron spin resonance spectroscopy and can be bonded to another molecule. (McGraw-Hill Dictionary of Chemical and Technical Terms, 4th ed)
Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.
Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.
A technique for detecting short-lived reactive FREE RADICALS in biological systems by providing a nitrone or nitrose compound for an addition reaction to occur which produces an ELECTRON SPIN RESONANCE SPECTROSCOPY-detectable aminoxyl radical. In spin trapping, the compound trapping the radical is called the spin trap and the addition product of the radical is identified as the spin adduct. (Free Rad Res Comm 1990;9(3-6):163)
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
The univalent radical OH. Hydroxyl radical is a potent oxidizing agent.
Inorganic oxides that contain nitrogen.
Inorganic compounds that contain the OH- group.
Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to METHEMOGLOBIN. In living organisms, SUPEROXIDE DISMUTASE protects the cell from the deleterious effects of superoxides.
Substances that influence the course of a chemical reaction by ready combination with free radicals. Among other effects, this combining activity protects pancreatic islets against damage by cytokines and prevents myocardial and pulmonary perfusion injuries.
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.
Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.
Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.
A synthetic phospholipid used in liposomes and lipid bilayers for the study of biological membranes.
The characteristic three-dimensional shape of a molecule.
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
An amino acid that occurs in vertebrate tissues and in urine. In muscle tissue, creatine generally occurs as phosphocreatine. Creatine is excreted as CREATININE in the urine.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
The measurement of the amplitude of the components of a complex waveform throughout the frequency range of the waveform. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
An endogenous substance found mainly in skeletal muscle of vertebrates. It has been tried in the treatment of cardiac disorders and has been added to cardioplegic solutions. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1996)
A group of compounds that are derivatives of octadecanoic acid which is one of the most abundant fatty acids found in animal lipids. (Stedman, 25th ed)
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
The rate dynamics in chemical or physical systems.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Stable cobalt atoms that have the same atomic number as the element cobalt, but differ in atomic weight. Co-59 is a stable cobalt isotope.
A basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism.
One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter.
A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Synthetic phospholipid used in liposomes and lipid bilayers to study biological membranes. It is also a major constituent of PULMONARY SURFACTANTS.
NMR spectroscopy on small- to medium-size biological macromolecules. This is often used for structural investigation of proteins and nucleic acids, and often involves more than one isotope.
A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.
That portion of the electromagnetic spectrum from the UHF (ultrahigh frequency) radio waves and extending into the INFRARED RAYS frequencies.
A group of compounds that contain a bivalent O-O group, i.e., the oxygen atoms are univalent. They can either be inorganic or organic in nature. Such compounds release atomic (nascent) oxygen readily. Thus they are strong oxidizing agents and fire hazards when in contact with combustible materials, especially under high-temperature conditions. The chief industrial uses of peroxides are as oxidizing agents, bleaching agents, and initiators of polymerization. (From Hawley's Condensed Chemical Dictionary, 11th ed)
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant.
Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.
Yoshida sarcoma is a rare and aggressive type of soft tissue cancer, specifically a malignant mesenchymal tumor, which was initially reported in Japan and typically occurs in children and young adults, often associated with a poor prognosis due to its rapid growth and high metastatic potential.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
Measurement of the intensity and quality of fluorescence.
The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)
An iron-molybdenum flavoprotein containing FLAVIN-ADENINE DINUCLEOTIDE that oxidizes hypoxanthine, some other purines and pterins, and aldehydes. Deficiency of the enzyme, an autosomal recessive trait, causes xanthinuria.
A chelating agent used as an antidote to heavy metal poisoning.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
An alkylating sulfhydryl reagent. Its actions are similar to those of iodoacetate.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
A dithiocarbamate chemical, used commercially in the rubber processing industry and as a fungicide. In vivo studies indicate that it inactivates the enzyme GLUTATHIONE REDUCTASE. It has mutagenic activity and may induce chromosomal aberrations.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
Insoluble polymers of TYROSINE derivatives found in and causing darkness in skin (SKIN PIGMENTATION), hair, and feathers providing protection against SUNBURN induced by SUNLIGHT. CAROTENES contribute yellow and red coloration.
The physical characteristics and processes of biological systems.
The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
The study of MAGNETIC PHENOMENA.
The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.
Nitroso compounds are organic or inorganic substances containing the nitroso functional group, which consists of a nitrogen atom bonded to an oxygen atom through a single covalent bond, often abbreviated as -NO.

Internal electron transfer between hemes and Cu(II) bound at cysteine beta93 promotes methemoglobin reduction by carbon monoxide. (1/6162)

Previous studies showed that CO/H2O oxidation provides electrons to drive the reduction of oxidized hemoglobin (metHb). We report here that Cu(II) addition accelerates the rate of metHb beta chain reduction by CO by a factor of about 1000. A mechanism whereby electron transfer occurs via an internal pathway coupling CO/H2O oxidation to Fe(III) and Cu(II) reduction is suggested by the observation that the copper-induced rate enhancement is inhibited by blocking Cys-beta93 with N-ethylmaleimide. Furthermore, this internal electron-transfer pathway is more readily established at low Cu(II) concentrations in Hb Deer Lodge (beta2His --> Arg) and other species lacking His-beta2 than in Hb A0. This difference is consistent with preferential binding of Cu(II) in Hb A0 to a high affinity site involving His-beta2, which is ineffective in promoting electron exchange between Cu(II) and the beta heme iron. Effective electron transfer is thus affected by Hb type but is not governed by the R left arrow over right arrow T conformational equilibrium. The beta hemes in Cu(II)-metHb are reduced under CO at rates close to those observed for cytochrome c oxidase, where heme and copper are present together in the oxygen-binding site and where internal electron transfer also occurs.  (+info)

The role of proline and glycine in determining the backbone flexibility of a channel-forming peptide. (2/6162)

Alamethicin is a helical 20-amino acid voltage-gated channel-forming peptide, which is known to exhibit segmental flexibility in solution along its backbone near alpha-methylalanine (MeA)-10 and Gly-11. In an alpha-helical configuration, MeA at position 10 would normally hydrogen-bond with position 14, but the presence of proline at this position prevents the formation of this interhelical hydrogen bond. To determine whether the presence of proline at position 14 contributes to the flexibility of this helix, two analogs of alamethicin were synthesized, one with proline 14 replaced by alanine and another with both proline 14 and glycine 11 replaced by alanine. The C-termini of these peptides were derivatized with a proxyl nitroxide, and paramagnetic enhancements produced by the nitroxide on the Calpha protons were used to estimate r-6 weighted distances between the nitroxide and the backbone protons. When compared to native alamethicin, the analog lacking proline 14 exhibited similar C-terminal to Calpha proton distances, indicating that substitution of proline alone does not alter the flexibility of this helix; however, the subsequent removal of glycine 11 resulted in a significant increase in the averaged distances between the C- and N-termini. Thus, the G-X-X-P motif found in alamethicin appears to be largely responsible for mediating high-amplitude bending motions that have been observed in the central helical domain of alamethicin in methanol. To determine whether these substitutions alter the channel behavior of alamethicin, the macroscopic and single-channel currents produced by these analogs were compared. Although the substitution of the G-X-X-P motif produces channels with altered characteristics, this motif is not essential to achieve voltage-dependent gating or alamethicin-like behavior.  (+info)

Copper binding to the prion protein: structural implications of four identical cooperative binding sites. (3/6162)

Evidence is growing to support a functional role for the prion protein (PrP) in copper metabolism. Copper ions appear to bind to the protein in a highly conserved octapeptide repeat region (sequence PHGGGWGQ) near the N terminus. To delineate the site and mode of binding of Cu(II) to the PrP, the copper-binding properties of peptides of varying lengths corresponding to 2-, 3-, and 4-octarepeat sequences have been probed by using various spectroscopic techniques. A two-octarepeat peptide binds a single Cu(II) ion with Kd approximately 6 microM whereas a four-octarepeat peptide cooperatively binds four Cu(II) ions. Circular dichroism spectra indicate a distinctive structuring of the octarepeat region on Cu(II) binding. Visible absorption, visible circular dichroism, and electron spin resonance spectra suggest that the coordination sphere of the copper is identical for 2, 3, or 4 octarepeats, consisting of a square-planar geometry with three nitrogen ligands and one oxygen ligand. Consistent with the pH dependence of Cu(II) binding, proton NMR spectroscopy indicates that the histidine residues in each octarepeat are coordinated to the Cu(II) ion. Our working model for the structure of the complex shows the histidine residues in successive octarepeats bridged between two copper ions, with both the Nepsilon2 and Ndelta1 imidazole nitrogen of each histidine residue coordinated and the remaining coordination sites occupied by a backbone amide nitrogen and a water molecule. This arrangement accounts for the cooperative nature of complex formation and for the apparent evolutionary requirement for four octarepeats in the PrP.  (+info)

A functional model for O-O bond formation by the O2-evolving complex in photosystem II. (4/6162)

The formation of molecular oxygen from water in photosynthesis is catalyzed by photosystem II at an active site containing four manganese ions that are arranged in di-mu-oxo dimanganese units (where mu is a bridging mode). The complex [H2O(terpy)Mn(O)2Mn(terpy)OH2](NO3)3 (terpy is 2,2':6', 2"-terpyridine), which was synthesized and structurally characterized, contains a di-mu-oxo manganese dimer and catalyzes the conversion of sodium hypochlorite to molecular oxygen. Oxygen-18 isotope labeling showed that water is the source of the oxygen atoms in the molecular oxygen evolved, and so this system is a functional model for photosynthetic water oxidation.  (+info)

Chlamydomonas chloroplast ferrous hemoglobin. Heme pocket structure and reactions with ligands. (5/6162)

We report the optical and resonance Raman spectral characterization of ferrous recombinant Chlamydomonas LI637 hemoglobin. We show that it is present in three pH-dependent equilibrium forms including a 4-coordinate species at acid pH, a 5-coordinate high spin species at neutral pH, and a 6-coordinate low spin species at alkaline pH. The proximal ligand to the heme is the imidazole group of a histidine. Kinetics of the reactions with ligands were determined by stopped-flow spectroscopy. At alkaline pH, combination with oxygen, nitric oxide, and carbon monoxide displays a kinetic behavior that is interpreted as being rate-limited by conversion of the 6-coordinate form to a reactive 5-coordinate form. At neutral pH, combination rates of the 5-coordinate form with oxygen and carbon monoxide were much faster (>10(7) microM-1 s-1). The dissociation rate constant measured for oxygen is among the slowest known, 0.014 s-1, and is independent of pH. Replacement of the tyrosine 63 (B10) by leucine or of the putative distal glutamine by glycine increases the dissociation rate constant 70- and 30-fold and increases the rate of autoxidation 20- and 90-fold, respectively. These results are consistent with at least two hydrogen bonds stabilizing the bound oxygen molecule, one from tyrosine B10 and the other from the distal glutamine. In addition, the high frequency (232 cm-1) of the iron-histidine bond suggests a structure that lacks any proximal strain thus contributing to high ligand affinity.  (+info)

Binding of Cob(II)alamin to the adenosylcobalamin-dependent ribonucleotide reductase from Lactobacillus leichmannii. Identification of dimethylbenzimidazole as the axial ligand. (6/6162)

The ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii catalyzes the reduction of nucleoside 5'-triphosphates to 2'-deoxynucleoside 5'-triphosphates and uses coenzyme B12, adenosylcobalamin (AdoCbl), as a cofactor. Use of a mechanism-based inhibitor, 2'-deoxy-2'-methylenecytidine 5'-triphosphate, and isotopically labeled RTPR and AdoCbl in conjunction with EPR spectroscopy has allowed identification of the lower axial ligand of cob(II)alamin when bound to RTPR. In common with the AdoCbl-dependent enzymes catalyzing irreversible heteroatom migrations and in contrast to the enzymes catalyzing reversible carbon skeleton rearrangements, the dimethylbenzimidazole moiety of the cofactor is not displaced by a protein histidine upon binding to RTPR.  (+info)

EPR spectroscopy of VO2+-ATP bound to catalytic site 3 of chloroplast F1-ATPase from Chlamydomonas reveals changes in metal ligation resulting from mutations to the phosphate-binding loop threonine (betaT168). (7/6162)

Site-directed mutations were made to the phosphate-binding loop threonine in the beta-subunit of the chloroplast F1-ATPase in Chlamydomonas (betaT168). Rates of photophosphorylation and ATPase-driven proton translocation measured in coupled thylakoids purified from betaT168D, betaT168C, and betaT168L mutants had <10% of the wild type rates, as did rates of Mg2+-ATPase activity of purified chloroplast F1-ATPase (CF1). The EPR spectra of VO2+-ATP bound to Site 3 of CF1 from wild type and mutants showed that EPR species C, formed exclusively upon activation, was altered in CF1 from each mutant in both signal intensity and in 51V hyperfine parameters that depend on the equatorial VO2+ ligands. These data provide the first direct evidence that Site 3 is a catalytic site. No significant differences between wild type and mutants were observed in EPR species B, the predominant form of the latent enzyme. Thus, the phosphate-binding loop threonine is an equatorial metal ligand in the activated conformation but not in the latent conformation of Site 3. The metal-nucleotide conformation that gives rise to species B is consistent with the Mg2+-ADP complex that becomes entrapped in a catalytic site in a manner that regulates enzymatic activity. The lack of catalytic function of CF1 with entrapped Mg2+-ADP may be explained in part by the absence of the phosphate-binding loop threonine as a metal ligand.  (+info)

Evidence for the head domain movement of the rieske iron-sulfur protein in electron transfer reaction of the cytochrome bc1 complex. (8/6162)

The three-dimensional structure of the mitochondrial cytochrome bc1 complex suggests that movement of the extramembrane domain (head) of the Rieske iron-sulfur protein (ISP) may play an important role in electron transfer. Such movement requires flexibility in the neck region of ISP, since the head and transmembrane domains of the protein are rather rigid. To test this hypothesis, Rhodobacter sphaeroides mutants expressing His-tagged cytochrome bc1 complexes with cysteine substitution at various positions in the ISP neck (residues 39-48) were generated and characterized. The mutants with a single cysteine substitution at Ala42 or Val44 and a double cysteine substitution at Val44 and Ala46 (VQA-CQC) or at Ala42 and Ala46 (ADVQA-CDVQC) have photosynthetic growth rates comparable with that of complement cells. Chromatophore membrane and intracytoplasmic membrane (ICM) prepared from these mutants have cytochrome bc1 complex activity similar to that in the complement membranes, indicating that flexibility of the neck region of ISP was not affected by these cysteine substitutions. Mutants with a double cysteine substitution at Ala42 and Val44 (ADV-CDC) or at Pro40 and Ala42 (PSA-CSC) have a retarded (50%) or no photosynthetic growth rate, respectively. The ADV-CDC or PSA-CSC mutant ICM contains 20 or 0% of the cytochrome bc1 complex activity found in the complement ICM. However, activity can be restored by the treatment with beta-mercaptoethanol (beta-ME). The restored activity is diminished upon removal of beta-ME but is retained if the beta-ME-treated membrane is treated with the sulfhydryl reagent N-ethylmaleimide or p-chloromercuribenzoic acid. These results indicate that the loss of bc1 complex activity in the ADV-CDC or PSA-CSC mutant membranes is due to disulfide bond formation, which increases the rigidity of ISP neck and, in turn, decreases the mobility of the head domain. Using the conditions developed for the isolation of His-tagged complement cytochrome bc1 complex, a two-subunit complex (cytochromes b and c1) is obtained from all of the double cysteine-substituted mutants. This suggests that introduction of two cysteines in the neck region of ISP weakens the interactions between cytochromes b, ISP, and subunit IV.  (+info)

Electron Spin Resonance (ESR) Spectroscopy, also known as Electron Paramagnetic Resonance (EPR) Spectroscopy, is a technique used to investigate materials with unpaired electrons. It is based on the principle of absorption of energy by the unpaired electrons when they are exposed to an external magnetic field and microwave radiation.

In this technique, a sample is placed in a magnetic field and microwave radiation is applied. The unpaired electrons in the sample absorb energy and change their spin state when the energy of the microwaves matches the energy difference between the spin states. This absorption of energy is recorded as a function of the magnetic field strength, producing an ESR spectrum.

ESR spectroscopy can provide information about the number, type, and behavior of unpaired electrons in a sample, as well as the local environment around the electron. It is widely used in physics, chemistry, and biology to study materials such as free radicals, transition metal ions, and defects in solids.

"Spin labels" are a term used in the field of magnetic resonance, including nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). They refer to molecules or atoms that have been chemically attached to a system of interest and possess a stable, unpaired electron. This unpaired electron behaves like a tiny magnet and can be manipulated using magnetic fields and radiofrequency pulses in EPR experiments. The resulting changes in the electron's spin state can provide information about the local environment, dynamics, and structure of the system to which it is attached. Spin labels are often used in biochemistry and materials science to study complex biological systems or materials at the molecular level.

Free radicals are molecules or atoms that have one or more unpaired electrons in their outermost shell, making them highly reactive. They can be formed naturally in the body through processes such as metabolism and exercise, or they can come from external sources like pollution, radiation, and certain chemicals. Free radicals can cause damage to cells and contribute to the development of various diseases, including cancer, cardiovascular disease, and neurodegenerative disorders. Antioxidants are substances that can neutralize free radicals and help protect against their harmful effects.

Cyclic N-oxides are a class of organic compounds that contain a cyclic structure with a nitrogen atom bonded to an oxygen atom as an N-oxide. An N-oxide is a compound in which the nitrogen atom has a positive charge and the oxygen atom has a negative charge, forming a polar covalent bond. In cyclic N-oxides, this N-O group is part of a ring structure, which can be composed of various combinations of carbon, nitrogen, and other atoms. These compounds have been studied for their potential use in pharmaceuticals, agrochemicals, and materials science.

Spin trapping is a technique used in free radical research to detect and study short-lived, reactive free radicals. It involves the use of spin trap compounds, which react with the radicals to form more stable, longer-lived radical adducts. These adducts can then be detected and analyzed using various techniques such as electron paramagnetic resonance (EPR) spectroscopy.

The spin trap compound is typically a nitrone or nitroso compound, which reacts with the free radical to form a nitroxide radical. The nitroxide radical has a characteristic EPR spectrum that can be used to identify and quantify the original free radical. This technique allows for the direct detection and measurement of free radicals in biological systems, providing valuable insights into their role in various physiological and pathological processes.

Magnetic Resonance Spectroscopy (MRS) is a non-invasive diagnostic technique that provides information about the biochemical composition of tissues, including their metabolic state. It is often used in conjunction with Magnetic Resonance Imaging (MRI) to analyze various metabolites within body tissues, such as the brain, heart, liver, and muscles.

During MRS, a strong magnetic field, radio waves, and a computer are used to produce detailed images and data about the concentration of specific metabolites in the targeted tissue or organ. This technique can help detect abnormalities related to energy metabolism, neurotransmitter levels, pH balance, and other biochemical processes, which can be useful for diagnosing and monitoring various medical conditions, including cancer, neurological disorders, and metabolic diseases.

There are different types of MRS, such as Proton (^1^H) MRS, Phosphorus-31 (^31^P) MRS, and Carbon-13 (^13^C) MRS, each focusing on specific elements or metabolites within the body. The choice of MRS technique depends on the clinical question being addressed and the type of information needed for diagnosis or monitoring purposes.

A hydroxyl radical is defined in biochemistry and medicine as an extremely reactive species, characterized by the presence of an oxygen atom bonded to a hydrogen atom (OH-). It is formed when a water molecule (H2O) is split into a hydroxide ion (OH-) and a hydrogen ion (H+) in the process of oxidation.

In medical terms, hydroxyl radicals are important in understanding free radical damage and oxidative stress, which can contribute to the development of various diseases, including cancer, cardiovascular disease, and neurodegenerative disorders. They are also involved in the body's natural defense mechanisms against pathogens. However, an overproduction of hydroxyl radicals can cause damage to cellular components such as DNA, proteins, and lipids, leading to cell dysfunction and death.

Nitrogen oxides (NOx) are a group of highly reactive gases, primarily composed of nitric oxide (NO) and nitrogen dioxide (NO2). They are formed during the combustion of fossil fuels, such as coal, oil, gas, or biomass, and are emitted from various sources, including power plants, industrial boilers, transportation vehicles, and residential heating systems. Exposure to NOx can have adverse health effects, particularly on the respiratory system, and contribute to the formation of harmful air pollutants like ground-level ozone and fine particulate matter.

Hydroxides are inorganic compounds that contain the hydroxide ion (OH−). They are formed when a base, which is an electron pair donor, reacts with water. The hydroxide ion consists of one oxygen atom and one hydrogen atom, and it carries a negative charge. Hydroxides are basic in nature due to their ability to donate hydroxide ions in solution, which increases the pH and makes the solution more alkaline. Common examples of hydroxides include sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium hydroxide (Ca(OH)2). They have various applications in industry, medicine, and research.

Superoxides are partially reduced derivatives of oxygen that contain one extra electron, giving them an overall charge of -1. They are highly reactive and unstable, with the most common superoxide being the hydroxyl radical (•OH-) and the superoxide anion (O2-). Superoxides are produced naturally in the body during metabolic processes, particularly within the mitochondria during cellular respiration. They play a role in various physiological processes, but when produced in excess or not properly neutralized, they can contribute to oxidative stress and damage to cells and tissues, potentially leading to the development of various diseases such as cancer, atherosclerosis, and neurodegenerative disorders.

Free radical scavengers, also known as antioxidants, are substances that neutralize or stabilize free radicals. Free radicals are highly reactive atoms or molecules with unpaired electrons, capable of causing damage to cells and tissues in the body through a process called oxidative stress. Antioxidants donate an electron to the free radical, thereby neutralizing it and preventing it from causing further damage. They can be found naturally in foods such as fruits, vegetables, and nuts, or they can be synthesized and used as dietary supplements. Examples of antioxidants include vitamins C and E, beta-carotene, and selenium.

Membrane lipids are the main component of biological membranes, forming a lipid bilayer in which various cellular processes take place. These lipids include phospholipids, glycolipids, and cholesterol. Phospholipids are the most abundant type, consisting of a hydrophilic head (containing a phosphate group) and two hydrophobic tails (composed of fatty acid chains). Glycolipids contain a sugar group attached to the lipid molecule. Cholesterol helps regulate membrane fluidity and permeability. Together, these lipids create a selectively permeable barrier that separates cells from their environment and organelles within cells.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

Reactive Oxygen Species (ROS) are highly reactive molecules containing oxygen, including peroxides, superoxide, hydroxyl radical, and singlet oxygen. They are naturally produced as byproducts of normal cellular metabolism in the mitochondria, and can also be generated by external sources such as ionizing radiation, tobacco smoke, and air pollutants. At low or moderate concentrations, ROS play important roles in cell signaling and homeostasis, but at high concentrations, they can cause significant damage to cell structures, including lipids, proteins, and DNA, leading to oxidative stress and potential cell death.

Quinones are a class of organic compounds that contain a fully conjugated diketone structure. This structure consists of two carbonyl groups (C=O) separated by a double bond (C=C). Quinones can be found in various biological systems and synthetic compounds. They play important roles in many biochemical processes, such as electron transport chains and redox reactions. Some quinones are also known for their antimicrobial and anticancer properties. However, some quinones can be toxic or mutagenic at high concentrations.

Temperature, in a medical context, is a measure of the degree of hotness or coldness of a body or environment. It is usually measured using a thermometer and reported in degrees Celsius (°C), degrees Fahrenheit (°F), or kelvin (K). In the human body, normal core temperature ranges from about 36.5-37.5°C (97.7-99.5°F) when measured rectally, and can vary slightly depending on factors such as time of day, physical activity, and menstrual cycle. Elevated body temperature is a common sign of infection or inflammation, while abnormally low body temperature can indicate hypothermia or other medical conditions.

Oxidative stress is defined as an imbalance between the production of reactive oxygen species (free radicals) and the body's ability to detoxify them or repair the damage they cause. This imbalance can lead to cellular damage, oxidation of proteins, lipids, and DNA, disruption of cellular functions, and activation of inflammatory responses. Prolonged or excessive oxidative stress has been linked to various health conditions, including cancer, cardiovascular diseases, neurodegenerative disorders, and aging-related diseases.

Nitric oxide (NO) is a molecule made up of one nitrogen atom and one oxygen atom. In the body, it is a crucial signaling molecule involved in various physiological processes such as vasodilation, immune response, neurotransmission, and inhibition of platelet aggregation. It is produced naturally by the enzyme nitric oxide synthase (NOS) from the amino acid L-arginine. Inhaled nitric oxide is used medically to treat pulmonary hypertension in newborns and adults, as it helps to relax and widen blood vessels, improving oxygenation and blood flow.

Medical Definition:

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic imaging technique that uses a strong magnetic field and radio waves to create detailed cross-sectional or three-dimensional images of the internal structures of the body. The patient lies within a large, cylindrical magnet, and the scanner detects changes in the direction of the magnetic field caused by protons in the body. These changes are then converted into detailed images that help medical professionals to diagnose and monitor various medical conditions, such as tumors, injuries, or diseases affecting the brain, spinal cord, heart, blood vessels, joints, and other internal organs. MRI does not use radiation like computed tomography (CT) scans.

An electron is a subatomic particle, symbol e-, with a negative electric charge. Electrons are fundamental components of atoms and are responsible for the chemical bonding between atoms to form molecules. They are located in an atom's electron cloud, which is the outermost region of an atom and contains negatively charged electrons that surround the positively charged nucleus.

Electrons have a mass that is much smaller than that of protons or neutrons, making them virtually weightless on the atomic scale. They are also known to exhibit both particle-like and wave-like properties, which is a fundamental concept in quantum mechanics. Electrons play a crucial role in various physical phenomena, such as electricity, magnetism, and chemical reactions.

Dimyristoylphosphatidylcholine (DMPC) is a type of phospholipid molecule that is commonly found in animal cell membranes. It is composed of two myristoyl fatty acid chains, a phosphate group, and a choline headgroup. DMPC has a gel-to-liquid crystalline phase transition temperature of around 23-25°C, which makes it a useful compound for studying the physical properties of lipid membranes and for creating model membrane systems in laboratory experiments.

Molecular conformation, also known as spatial arrangement or configuration, refers to the specific three-dimensional shape and orientation of atoms that make up a molecule. It describes the precise manner in which bonds between atoms are arranged around a molecular framework, taking into account factors such as bond lengths, bond angles, and torsional angles.

Conformational isomers, or conformers, are different spatial arrangements of the same molecule that can interconvert without breaking chemical bonds. These isomers may have varying energies, stability, and reactivity, which can significantly impact a molecule's biological activity and function. Understanding molecular conformation is crucial in fields such as drug design, where small changes in conformation can lead to substantial differences in how a drug interacts with its target.

The Electron Transport Chain (ETC) is a series of complexes in the inner mitochondrial membrane that are involved in the process of cellular respiration. It is the final pathway for electrons derived from the oxidation of nutrients such as glucose, fatty acids, and amino acids to be transferred to molecular oxygen. This transfer of electrons drives the generation of a proton gradient across the inner mitochondrial membrane, which is then used by ATP synthase to produce ATP, the main energy currency of the cell.

The electron transport chain consists of four complexes (I-IV) and two mobile electron carriers (ubiquinone and cytochrome c). Electrons from NADH and FADH2 are transferred to Complex I and Complex II respectively, which then pass them along to ubiquinone. Ubiquinone then transfers the electrons to Complex III, which passes them on to cytochrome c. Finally, cytochrome c transfers the electrons to Complex IV, where they combine with oxygen and protons to form water.

The transfer of electrons through the ETC is accompanied by the pumping of protons from the mitochondrial matrix to the intermembrane space, creating a proton gradient. The flow of protons back across the inner membrane through ATP synthase drives the synthesis of ATP from ADP and inorganic phosphate.

Overall, the electron transport chain is a crucial process for generating energy in the form of ATP in the cell, and it plays a key role in many metabolic pathways.

Membrane fluidity, in the context of cell biology, refers to the ability of the phospholipid bilayer that makes up the cell membrane to change its structure and organization in response to various factors. The membrane is not a static structure but rather a dynamic one, with its lipids constantly moving and changing position.

Membrane fluidity is determined by the fatty acid composition of the phospholipids that make up the bilayer. Lipids with unsaturated fatty acids have kinks in their hydrocarbon chains, which prevent them from packing closely together and increase membrane fluidity. In contrast, lipids with saturated fatty acids can pack closely together, reducing membrane fluidity.

Membrane fluidity is important for various cellular processes, including the movement of proteins within the membrane, the fusion of vesicles with the membrane during exocytosis and endocytosis, and the ability of the membrane to respond to changes in temperature and other environmental factors. Abnormalities in membrane fluidity have been linked to various diseases, including cancer, neurological disorders, and infectious diseases.

Creatine is a organic acid that is produced naturally in the liver, kidneys and pancreas. It is also found in small amounts in certain foods such as meat and fish. The chemical formula for creatine is C4H9N3O2. In the body, creatine is converted into creatine phosphate, which is used to help produce energy during high-intensity exercise, such as weightlifting or sprinting.

Creatine can also be taken as a dietary supplement, in the form of creatine monohydrate, with the goal of increasing muscle creatine and phosphocreatine levels, which may improve athletic performance and help with muscle growth. However, it is important to note that while some studies have found that creatine supplementation can improve exercise performance and muscle mass in certain populations, others have not found significant benefits.

Creatine supplements are generally considered safe when used as directed, but they can cause side effects such as weight gain, stomach discomfort, and muscle cramps in some people. It is always recommended to consult a healthcare professional before starting any new supplement regimen.

Electron microscopy (EM) is a type of microscopy that uses a beam of electrons to create an image of the sample being examined, resulting in much higher magnification and resolution than light microscopy. There are several types of electron microscopy, including transmission electron microscopy (TEM), scanning electron microscopy (SEM), and reflection electron microscopy (REM).

In TEM, a beam of electrons is transmitted through a thin slice of the sample, and the electrons that pass through the sample are focused to form an image. This technique can provide detailed information about the internal structure of cells, viruses, and other biological specimens, as well as the composition and structure of materials at the atomic level.

In SEM, a beam of electrons is scanned across the surface of the sample, and the electrons that are scattered back from the surface are detected to create an image. This technique can provide information about the topography and composition of surfaces, as well as the structure of materials at the microscopic level.

REM is a variation of SEM in which the beam of electrons is reflected off the surface of the sample, rather than scattered back from it. This technique can provide information about the surface chemistry and composition of materials.

Electron microscopy has a wide range of applications in biology, medicine, and materials science, including the study of cellular structure and function, disease diagnosis, and the development of new materials and technologies.

Phosphatidylcholines (PtdCho) are a type of phospholipids that are essential components of cell membranes in living organisms. They are composed of a hydrophilic head group, which contains a choline moiety, and two hydrophobic fatty acid chains. Phosphatidylcholines are crucial for maintaining the structural integrity and function of cell membranes, and they also serve as important precursors for the synthesis of signaling molecules such as acetylcholine. They can be found in various tissues and biological fluids, including blood, and are abundant in foods such as soybeans, eggs, and meat. Phosphatidylcholines have been studied for their potential health benefits, including their role in maintaining healthy lipid metabolism and reducing the risk of cardiovascular disease.

I'm sorry for any confusion, but "spectrum analysis" is not a commonly used medical term. Spectrum analysis is a term that is more frequently used in the fields of physics, mathematics, and engineering to describe the process of breaking down a signal or a wave into its different frequencies and amplitudes, creating a visual representation called a spectrum.

If you have any concerns about a medical issue, I would recommend consulting with a healthcare professional for accurate information and guidance.

A lipid bilayer is a thin membrane made up of two layers of lipid molecules, primarily phospholipids. The hydrophilic (water-loving) heads of the lipids face outwards, coming into contact with watery environments on both sides, while the hydrophobic (water-fearing) tails point inward, away from the aqueous surroundings. This unique structure allows lipid bilayers to form a stable barrier that controls the movement of molecules and ions in and out of cells and organelles, thus playing a crucial role in maintaining cellular compartmentalization and homeostasis.

Phosphocreatine (PCr) is a high-energy phosphate compound found in the skeletal muscles, cardiac muscle, and brain. It plays a crucial role in energy metabolism and storage within cells. Phosphocreatine serves as an immediate energy reserve that helps regenerate ATP (adenosine triphosphate), the primary source of cellular energy, during short bursts of intense activity or stress. This process is facilitated by the enzyme creatine kinase, which catalyzes the transfer of a phosphate group from phosphocreatine to ADP (adenosine diphosphate) to form ATP.

In a medical context, phosphocreatine levels may be assessed in muscle biopsies or magnetic resonance spectroscopy (MRS) imaging to evaluate muscle energy metabolism and potential mitochondrial dysfunction in conditions such as muscular dystrophies, mitochondrial disorders, and neuromuscular diseases. Additionally, phosphocreatine depletion has been implicated in various pathological processes, including ischemia-reperfusion injury, neurodegenerative disorders, and heart failure.

Stearic acid is not typically considered a medical term, but rather a chemical compound. It is a saturated fatty acid with the chemical formula C18H36O2. Stearic acid is commonly found in various foods such as animal fats and vegetable oils, including cocoa butter and palm oil.

In a medical context, stearic acid might be mentioned in relation to nutrition or cosmetics. For example, it may be listed as an ingredient in some skincare products or medications where it is used as an emollient or thickening agent. It's also worth noting that while stearic acid is a saturated fat, some studies suggest that it may have a more neutral effect on blood cholesterol levels compared to other saturated fats. However, this is still a topic of ongoing research and debate in the medical community.

In the context of medicine, particularly in relation to cancer treatment, protons refer to positively charged subatomic particles found in the nucleus of an atom. Proton therapy, a type of radiation therapy, uses a beam of protons to target and destroy cancer cells with high precision, minimizing damage to surrounding healthy tissue. The concentrated dose of radiation is delivered directly to the tumor site, reducing side effects and improving quality of life during treatment.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

Cobalt isotopes are variants of the chemical element Cobalt (Co) that have different numbers of neutrons in their atomic nuclei. This results in the different isotopes having slightly different masses and varying levels of stability.

The most naturally occurring stable cobalt isotope is Co-59, which contains 27 neutrons in its nucleus. However, there are also several radioactive isotopes of cobalt, including Co-60, which is a commonly used medical and industrial radioisotope.

Co-60 has 30 neutrons in its nucleus and undergoes beta decay, emitting gamma rays and becoming Nickel-60. It has a half-life of approximately 5.27 years, making it useful for a variety of applications, including cancer treatment, industrial radiography, and sterilization of medical equipment.

Other radioactive isotopes of cobalt include Co-57, which has a half-life of 271.8 days and is used in medical imaging, and Co-56, which has a half-life of just 77.2 seconds and is used in research.

Choline is an essential nutrient that is vital for the normal functioning of all cells, particularly those in the brain and liver. It is a water-soluble compound that is neither a vitamin nor a mineral, but is often grouped with vitamins because it has many similar functions. Choline is a precursor to the neurotransmitter acetylcholine, which plays an important role in memory, mood, and other cognitive processes. It also helps to maintain the structural integrity of cell membranes and is involved in the transport and metabolism of fats.

Choline can be synthesized by the body in small amounts, but it is also found in a variety of foods such as eggs, meat, fish, nuts, and cruciferous vegetables. Some people may require additional choline through supplementation, particularly if they follow a vegetarian or vegan diet, are pregnant or breastfeeding, or have certain medical conditions that affect choline metabolism.

Deficiency in choline can lead to a variety of health problems, including liver disease, muscle damage, and neurological disorders. On the other hand, excessive intake of choline can cause fishy body odor, sweating, and gastrointestinal symptoms such as diarrhea and vomiting. It is important to maintain adequate levels of choline through a balanced diet and, if necessary, supplementation under the guidance of a healthcare professional.

Aspartic acid is an α-amino acid with the chemical formula HO2CCH(NH2)CO2H. It is one of the twenty standard amino acids, and it is a polar, negatively charged, and hydrophilic amino acid. In proteins, aspartic acid usually occurs in its ionized form, aspartate, which has a single negative charge.

Aspartic acid plays important roles in various biological processes, including metabolism, neurotransmitter synthesis, and energy production. It is also a key component of many enzymes and proteins, where it often contributes to the formation of ionic bonds and helps stabilize protein structure.

In addition to its role as a building block of proteins, aspartic acid is also used in the synthesis of other important biological molecules, such as nucleotides, which are the building blocks of DNA and RNA. It is also a component of the dipeptide aspartame, an artificial sweetener that is widely used in food and beverages.

Like other amino acids, aspartic acid is essential for human health, but it cannot be synthesized by the body and must be obtained through the diet. Foods that are rich in aspartic acid include meat, poultry, fish, dairy products, eggs, legumes, and some fruits and vegetables.

Hydrogen peroxide (H2O2) is a colorless, odorless, clear liquid with a slightly sweet taste, although drinking it is harmful and can cause poisoning. It is a weak oxidizing agent and is used as an antiseptic and a bleaching agent. In diluted form, it is used to disinfect wounds and kill bacteria and viruses on the skin; in higher concentrations, it can be used to bleach hair or remove stains from clothing. It is also used as a propellant in rocketry and in certain industrial processes. Chemically, hydrogen peroxide is composed of two hydrogen atoms and two oxygen atoms, and it is structurally similar to water (H2O), with an extra oxygen atom. This gives it its oxidizing properties, as the additional oxygen can be released and used to react with other substances.

Oxygen is a colorless, odorless, tasteless gas that constitutes about 21% of the earth's atmosphere. It is a crucial element for human and most living organisms as it is vital for respiration. Inhaled oxygen enters the lungs and binds to hemoglobin in red blood cells, which carries it to tissues throughout the body where it is used to convert nutrients into energy and carbon dioxide, a waste product that is exhaled.

Medically, supplemental oxygen therapy may be provided to patients with conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, or other medical conditions that impair the body's ability to extract sufficient oxygen from the air. Oxygen can be administered through various devices, including nasal cannulas, face masks, and ventilators.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Scanning electron microscopy (SEM) is a type of electron microscopy that uses a focused beam of electrons to scan the surface of a sample and produce a high-resolution image. In SEM, a beam of electrons is scanned across the surface of a specimen, and secondary electrons are emitted from the sample due to interactions between the electrons and the atoms in the sample. These secondary electrons are then detected by a detector and used to create an image of the sample's surface topography. SEM can provide detailed images of the surface of a wide range of materials, including metals, polymers, ceramics, and biological samples. It is commonly used in materials science, biology, and electronics for the examination and analysis of surfaces at the micro- and nanoscale.

Medical definitions of water generally describe it as a colorless, odorless, tasteless liquid that is essential for all forms of life. It is a universal solvent, making it an excellent medium for transporting nutrients and waste products within the body. Water constitutes about 50-70% of an individual's body weight, depending on factors such as age, sex, and muscle mass.

In medical terms, water has several important functions in the human body:

1. Regulation of body temperature through perspiration and respiration.
2. Acting as a lubricant for joints and tissues.
3. Facilitating digestion by helping to break down food particles.
4. Transporting nutrients, oxygen, and waste products throughout the body.
5. Helping to maintain healthy skin and mucous membranes.
6. Assisting in the regulation of various bodily functions, such as blood pressure and heart rate.

Dehydration can occur when an individual does not consume enough water or loses too much fluid due to illness, exercise, or other factors. This can lead to a variety of symptoms, including dry mouth, fatigue, dizziness, and confusion. Severe dehydration can be life-threatening if left untreated.

1,2-Dipalmitoylphosphatidylcholine (DPPC) is a type of phospholipid molecule that is a major component of the lipid bilayer in biological membranes, particularly in lung surfactant. It is composed of two palmitic acid chains attached to a glycerol backbone, which is linked to a phosphate group and a choline headgroup. The chemical formula for DPPC is C44H86NO8P.

In the body, DPPC plays an important role in maintaining the structure and function of cell membranes, as well as reducing surface tension in the lungs. It is also used in research and medical settings as a component of liposomes, which are used for drug delivery and other biomedical applications.

Nuclear Magnetic Resonance (NMR) Biomolecular is a research technique that uses magnetic fields and radio waves to study the structure and dynamics of biological molecules, such as proteins and nucleic acids. This technique measures the magnetic properties of atomic nuclei within these molecules, specifically their spin, which can be influenced by the application of an external magnetic field.

When a sample is placed in a strong magnetic field, the nuclei absorb and emit electromagnetic radiation at specific frequencies, known as resonance frequencies, which are determined by the molecular structure and environment of the nuclei. By analyzing these resonance frequencies and their interactions, researchers can obtain detailed information about the three-dimensional structure, dynamics, and interactions of biomolecules.

NMR spectroscopy is a non-destructive technique that allows for the study of biological molecules in solution, which makes it an important tool for understanding the function and behavior of these molecules in their natural environment. Additionally, NMR can be used to study the effects of drugs, ligands, and other small molecules on biomolecular structure and dynamics, making it a valuable tool in drug discovery and development.

In the context of medicine, iron is an essential micromineral and key component of various proteins and enzymes. It plays a crucial role in oxygen transport, DNA synthesis, and energy production within the body. Iron exists in two main forms: heme and non-heme. Heme iron is derived from hemoglobin and myoglobin in animal products, while non-heme iron comes from plant sources and supplements.

The recommended daily allowance (RDA) for iron varies depending on age, sex, and life stage:

* For men aged 19-50 years, the RDA is 8 mg/day
* For women aged 19-50 years, the RDA is 18 mg/day
* During pregnancy, the RDA increases to 27 mg/day
* During lactation, the RDA for breastfeeding mothers is 9 mg/day

Iron deficiency can lead to anemia, characterized by fatigue, weakness, and shortness of breath. Excessive iron intake may result in iron overload, causing damage to organs such as the liver and heart. Balanced iron levels are essential for maintaining optimal health.

I'm sorry for any confusion, but "microwaves" is not a term typically used in medical definitions. Microwaves are a form of electromagnetic radiation with wavelengths ranging from one meter to one millimeter; they are commonly used in communication devices and home appliances such as microwave ovens. If you have any questions related to health or medicine, please provide more context so I can give you a more accurate response.

Peroxides, in a medical context, most commonly refer to chemical compounds that contain the peroxide ion (O2−2). Peroxides are characterized by the presence of an oxygen-oxygen single bond and can be found in various substances.

In dentistry, hydrogen peroxide (H2O2) is a widely used agent for teeth whitening or bleaching due to its oxidizing properties. It can help remove stains and discoloration on the tooth surface by breaking down into water and oxygen-free radicals, which react with the stain molecules, ultimately leading to their oxidation and elimination.

However, it is essential to note that high concentrations of hydrogen peroxide or prolonged exposure can cause tooth sensitivity, irritation to the oral soft tissues, and potential damage to the dental pulp. Therefore, professional supervision and appropriate concentration control are crucial when using peroxides for dental treatments.

A chemical model is a simplified representation or description of a chemical system, based on the laws of chemistry and physics. It is used to explain and predict the behavior of chemicals and chemical reactions. Chemical models can take many forms, including mathematical equations, diagrams, and computer simulations. They are often used in research, education, and industry to understand complex chemical processes and develop new products and technologies.

For example, a chemical model might be used to describe the way that atoms and molecules interact in a particular reaction, or to predict the properties of a new material. Chemical models can also be used to study the behavior of chemicals at the molecular level, such as how they bind to each other or how they are affected by changes in temperature or pressure.

It is important to note that chemical models are simplifications of reality and may not always accurately represent every aspect of a chemical system. They should be used with caution and validated against experimental data whenever possible.

Copper is a chemical element with the symbol Cu (from Latin: *cuprum*) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. Copper is found as a free element in nature, and it is also a constituent of many minerals such as chalcopyrite and bornite.

In the human body, copper is an essential trace element that plays a role in various physiological processes, including iron metabolism, energy production, antioxidant defense, and connective tissue synthesis. Copper is found in a variety of foods, such as shellfish, nuts, seeds, whole grains, and organ meats. The recommended daily intake of copper for adults is 900 micrograms (mcg) per day.

Copper deficiency can lead to anemia, neutropenia, impaired immune function, and abnormal bone development. Copper toxicity, on the other hand, can cause nausea, vomiting, abdominal pain, diarrhea, and in severe cases, liver damage and neurological symptoms. Therefore, it is important to maintain a balanced copper intake through diet and supplements if necessary.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.

Spectrophotometry is a technical analytical method used in the field of medicine and science to measure the amount of light absorbed or transmitted by a substance at specific wavelengths. This technique involves the use of a spectrophotometer, an instrument that measures the intensity of light as it passes through a sample.

In medical applications, spectrophotometry is often used in laboratory settings to analyze various biological samples such as blood, urine, and tissues. For example, it can be used to measure the concentration of specific chemicals or compounds in a sample by measuring the amount of light that is absorbed or transmitted at specific wavelengths.

In addition, spectrophotometry can also be used to assess the properties of biological tissues, such as their optical density and thickness. This information can be useful in the diagnosis and treatment of various medical conditions, including skin disorders, eye diseases, and cancer.

Overall, spectrophotometry is a valuable tool for medical professionals and researchers seeking to understand the composition and properties of various biological samples and tissues.

Ascorbic acid is the chemical name for Vitamin C. It is a water-soluble vitamin that is essential for human health. Ascorbic acid is required for the synthesis of collagen, a protein that plays a role in the structure of bones, tendons, ligaments, and blood vessels. It also functions as an antioxidant, helping to protect cells from damage caused by free radicals.

Ascorbic acid cannot be produced by the human body and must be obtained through diet or supplementation. Good food sources of vitamin C include citrus fruits, strawberries, bell peppers, broccoli, and spinach.

In the medical field, ascorbic acid is used to treat or prevent vitamin C deficiency and related conditions, such as scurvy. It may also be used in the treatment of various other health conditions, including common cold, cancer, and cardiovascular disease, although its effectiveness for these uses is still a matter of scientific debate.

Artificial membranes are synthetic or man-made materials that possess properties similar to natural biological membranes, such as selective permeability and barrier functions. These membranes can be designed to control the movement of molecules, ions, or cells across them, making them useful in various medical and biotechnological applications.

Examples of artificial membranes include:

1. Dialysis membranes: Used in hemodialysis for patients with renal failure, these semi-permeable membranes filter waste products and excess fluids from the blood while retaining essential proteins and cells.
2. Hemofiltration membranes: Utilized in extracorporeal circuits to remove larger molecules, such as cytokines or inflammatory mediators, from the blood during critical illnesses or sepsis.
3. Drug delivery systems: Artificial membranes can be used to encapsulate drugs, allowing for controlled release and targeted drug delivery in specific tissues or cells.
4. Tissue engineering: Synthetic membranes serve as scaffolds for cell growth and tissue regeneration, guiding the formation of new functional tissues.
5. Biosensors: Artificial membranes can be integrated into biosensing devices to selectively detect and quantify biomolecules, such as proteins or nucleic acids, in diagnostic applications.
6. Microfluidics: Artificial membranes are used in microfluidic systems for lab-on-a-chip applications, enabling the manipulation and analysis of small volumes of fluids for various medical and biological purposes.

I'm sorry for the confusion, but "Sarcoma, Yoshida" is not a recognized medical term or a specific type of sarcoma in any major oncology reference or database. It appears that "Yoshida" might be referring to a person who described or studied a particular type of sarcoma. However, I cannot find any relevant information related to this exact term.

Sarcomas are cancers that develop from connective tissues such as bones, muscles, tendons, cartilages, nerves, and blood vessels. They can be categorized into two main groups: bone sarcomas and soft tissue sarcomas. There are many subtypes of sarcoma, each with its unique features, diagnostic criteria, and treatment approaches.

If you have more context or information about "Sarcoma, Yoshida," I would be happy to help you further research the topic. However, based on the available data, it is not possible to provide a medical definition for this term.

Liposomes are artificially prepared, small, spherical vesicles composed of one or more lipid bilayers that enclose an aqueous compartment. They can encapsulate both hydrophilic and hydrophobic drugs, making them useful for drug delivery applications in the medical field. The lipid bilayer structure of liposomes is similar to that of biological membranes, which allows them to merge with and deliver their contents into cells. This property makes liposomes a valuable tool in delivering drugs directly to targeted sites within the body, improving drug efficacy while minimizing side effects.

Fluorescence spectrometry is a type of analytical technique used to investigate the fluorescent properties of a sample. It involves the measurement of the intensity of light emitted by a substance when it absorbs light at a specific wavelength and then re-emits it at a longer wavelength. This process, known as fluorescence, occurs because the absorbed energy excites electrons in the molecules of the substance to higher energy states, and when these electrons return to their ground state, they release the excess energy as light.

Fluorescence spectrometry typically measures the emission spectrum of a sample, which is a plot of the intensity of emitted light versus the wavelength of emission. This technique can be used to identify and quantify the presence of specific fluorescent molecules in a sample, as well as to study their photophysical properties.

Fluorescence spectrometry has many applications in fields such as biochemistry, environmental science, and materials science. For example, it can be used to detect and measure the concentration of pollutants in water samples, to analyze the composition of complex biological mixtures, or to study the properties of fluorescent nanomaterials.

In the context of medical terminology, "solutions" refers to a homogeneous mixture of two or more substances, in which one substance (the solute) is uniformly distributed within another substance (the solvent). The solvent is typically the greater component of the solution and is capable of dissolving the solute.

Solutions can be classified based on the physical state of the solvent and solute. For instance, a solution in which both the solvent and solute are liquids is called a liquid solution or simply a solution. A solid solution is one where the solvent is a solid and the solute is either a gas, liquid, or solid. Similarly, a gas solution refers to a mixture where the solvent is a gas and the solute can be a gas, liquid, or solid.

In medical applications, solutions are often used as vehicles for administering medications, such as intravenous (IV) fluids, oral rehydration solutions, eye drops, and topical creams or ointments. The composition of these solutions is carefully controlled to ensure the appropriate concentration and delivery of the active ingredients.

Xanthine oxidase is an enzyme that catalyzes the oxidation of xanthine to uric acid, which is the last step in purine metabolism. It's a type of molybdenum-containing oxidoreductase that generates reactive oxygen species (ROS) during its reaction mechanism.

The enzyme exists in two interconvertible forms: an oxidized state and a reduced state. The oxidized form, called xanthine oxidase, reduces molecular oxygen to superoxide and hydrogen peroxide, while the reduced form, called xanthine dehydrogenase, reduces NAD+ to NADH.

Xanthine oxidase is found in various tissues, including the liver, intestines, and milk. An overproduction of uric acid due to increased activity of xanthine oxidase can lead to hyperuricemia, which may result in gout or kidney stones. Some medications and natural compounds are known to inhibit xanthine oxidase, such as allopurinol and febuxostat, which are used to treat gout and prevent the formation of uric acid stones in the kidneys.

Unithiol is the common name for the drug compound mercaptopropionylglycine (MPG). It is a synthetic aminocarboxylic acid that acts as a chelating agent, binding to heavy metals in the body and facilitating their elimination. Unithiol has been used in the treatment of various conditions associated with heavy metal toxicity, such as Wilson's disease, lead poisoning, and mercury poisoning. It is also known for its potential use in protecting against chemotherapy-induced peripheral neuropathy.

In medical terms, Unithiol can be defined as:

A synthetic chelating agent with the chemical formula C5H9NO3S, used in the treatment of heavy metal poisoning to promote the excretion of toxic metals from the body. It is administered orally and works by forming stable complexes with heavy metals, which are then eliminated through urine. Unithiol has been found to be particularly effective in treating Wilson's disease, a genetic disorder that causes copper accumulation in various organs. Additionally, it may provide neuroprotective effects against chemotherapy-induced peripheral neuropathy.

I'm sorry for any confusion, but "thermodynamics" is not a term that has a specific medical definition. It is a branch of physics that deals with the relationships between heat and other forms of energy. However, the principles of thermodynamics can be applied to biological systems, including those in the human body, such as in the study of metabolism or muscle function. But in a medical context, "thermodynamics" would not be a term used independently as a diagnosis, treatment, or any medical condition.

Iodoacetamide is not typically defined in a medical context, but it is a chemical compound with the formula CH3C(=NH)COI. It is used in laboratory settings as a reagent for various chemical reactions. In a biochemical context, iodoacetamide is an alkylating agent that can react with cysteine residues in proteins, modifying their structure and function. This property has made it useful in research applications such as the study of protein function and enzyme kinetics.

However, it's important to note that iodoacetamide is not used as a therapeutic agent in medicine due to its potential toxicity and reactivity with various biological molecules. Therefore, there is no medical definition for this compound.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Near-infrared spectroscopy (NIRS) is a non-invasive optical technique that uses the near-infrared region of the electromagnetic spectrum (approximately 700-2500 nanometers) to analyze various chemical and physical properties of materials, primarily in the fields of biomedical research and industry. In medicine, NIRS is often used to measure tissue oxygenation, hemodynamics, and metabolism, providing valuable information about organ function and physiology. This technique is based on the principle that different molecules absorb and scatter near-infrared light differently, allowing for the identification and quantification of specific chromophores, such as oxyhemoglobin, deoxyhemoglobin, and cytochrome c oxidase. NIRS can be employed in a variety of clinical settings, including monitoring cerebral or muscle oxygenation during surgery, assessing tissue viability in wound healing, and studying brain function in neuroscience research.

The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:

1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.

The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.

Thiram is not typically considered a medical term, but it is a chemical compound that has been used in some medical and healthcare settings. Thiram is an organic compound that belongs to the class of chemicals known as dithiocarbamates. It is primarily used as a fungicide to prevent fungal growth on crops such as potatoes, beans, and nuts.

In medical contexts, thiram has been used in some topical creams and ointments as an antifungal agent to treat skin conditions like athlete's foot and ringworm. However, its use in medicine is relatively limited due to concerns about its potential toxicity and environmental impact.

It is important to note that the use of thiram in topical medications has declined over time, and it is not commonly used in modern medical practice. Always consult with a healthcare professional for accurate information regarding medical treatments and therapies.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

In the context of medicine, "chemistry" often refers to the field of study concerned with the properties, composition, and structure of elements and compounds, as well as their reactions with one another. It is a fundamental science that underlies much of modern medicine, including pharmacology (the study of drugs), toxicology (the study of poisons), and biochemistry (the study of the chemical processes that occur within living organisms).

In addition to its role as a basic science, chemistry is also used in medical testing and diagnosis. For example, clinical chemistry involves the analysis of bodily fluids such as blood and urine to detect and measure various substances, such as glucose, cholesterol, and electrolytes, that can provide important information about a person's health status.

Overall, chemistry plays a critical role in understanding the mechanisms of diseases, developing new treatments, and improving diagnostic tests and techniques.

Melanin is a pigment that determines the color of skin, hair, and eyes in humans and animals. It is produced by melanocytes, which are specialized cells found in the epidermis (the outer layer of the skin) and the choroid (the vascular coat of the eye). There are two main types of melanin: eumelanin and pheomelanin. Eumelanin is a black or brown pigment, while pheomelanin is a red or yellow pigment. The amount and type of melanin produced by an individual can affect their skin and hair color, as well as their susceptibility to certain diseases, such as skin cancer.

Biophysical phenomena refer to the observable events and processes that occur in living organisms, which can be explained and studied using the principles and methods of physics. These phenomena can include a wide range of biological processes at various levels of organization, from molecular interactions to whole-organism behaviors. Examples of biophysical phenomena include the mechanics of muscle contraction, the electrical activity of neurons, the transport of molecules across cell membranes, and the optical properties of biological tissues. By applying physical theories and techniques to the study of living systems, biophysicists seek to better understand the fundamental principles that govern life and to develop new approaches for diagnosing and treating diseases.

Chemical phenomena refer to the changes and interactions that occur at the molecular or atomic level when chemicals are involved. These phenomena can include chemical reactions, in which one or more substances (reactants) are converted into different substances (products), as well as physical properties that change as a result of chemical interactions, such as color, state of matter, and solubility. Chemical phenomena can be studied through various scientific disciplines, including chemistry, biochemistry, and physics.

Phospholipids are a major class of lipids that consist of a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails. The head is composed of a phosphate group, which is often bound to an organic molecule such as choline, ethanolamine, serine or inositol. The tails are made up of two fatty acid chains.

Phospholipids are a key component of cell membranes and play a crucial role in maintaining the structural integrity and function of the cell. They form a lipid bilayer, with the hydrophilic heads facing outwards and the hydrophobic tails facing inwards, creating a barrier that separates the interior of the cell from the outside environment.

Phospholipids are also involved in various cellular processes such as signal transduction, intracellular trafficking, and protein function regulation. Additionally, they serve as emulsifiers in the digestive system, helping to break down fats in the diet.

I'm sorry for any confusion, but "magnetics" is not a term that is commonly used in medical definitions. It is a term more frequently used in physics and engineering to refer to things related to magnets or magnetic fields. If you have any questions about medical terminology or concepts, I would be happy to try to help with those!

I'm sorry for any confusion, but there seems to be a misunderstanding. Mathematics is not a medical term; it is a branch of science dedicated to the study of numbers, shapes, and structures. However, mathematics does have many applications in medicine, such as in modeling disease spread, analyzing medical images, or designing clinical trials. If you have any questions related to mathematics in a medical context, I'd be happy to help clarify those for you!

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Biophysics is a interdisciplinary field that combines the principles and methods of physics with those of biology to study biological systems and phenomena. It involves the use of physical theories, models, and techniques to understand and explain the properties, functions, and behaviors of living organisms and their constituents, such as cells, proteins, and DNA.

Biophysics can be applied to various areas of biology, including molecular biology, cell biology, neuroscience, and physiology. It can help elucidate the mechanisms of biological processes at the molecular and cellular levels, such as protein folding, ion transport, enzyme kinetics, gene expression, and signal transduction. Biophysical methods can also be used to develop diagnostic and therapeutic tools for medical applications, such as medical imaging, drug delivery, and gene therapy.

Examples of biophysical techniques include X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, electron microscopy, fluorescence microscopy, atomic force microscopy, and computational modeling. These methods allow researchers to probe the structure, dynamics, and interactions of biological molecules and systems with high precision and resolution, providing insights into their functions and behaviors.

Benzoquinones are a type of chemical compound that contain a benzene ring (a cyclic arrangement of six carbon atoms) with two ketone functional groups (-C=O) in the 1,4-positions. They exist in two stable forms, namely ortho-benzoquinone and para-benzoquinone, depending on the orientation of the ketone groups relative to each other.

Benzoquinones are important intermediates in various biological processes and are also used in industrial applications such as dyes, pigments, and pharmaceuticals. They can be produced synthetically or obtained naturally from certain plants and microorganisms.

In the medical field, benzoquinones have been studied for their potential therapeutic effects, particularly in the treatment of cancer and infectious diseases. However, they are also known to exhibit toxicity and may cause adverse reactions in some individuals. Therefore, further research is needed to fully understand their mechanisms of action and potential risks before they can be safely used as drugs or therapies.

Manganese is not a medical condition, but it's an essential trace element that is vital for human health. Here is the medical definition of Manganese:

Manganese (Mn) is a trace mineral that is present in tiny amounts in the body. It is found mainly in bones, the liver, kidneys, and pancreas. Manganese helps the body form connective tissue, bones, blood clotting factors, and sex hormones. It also plays a role in fat and carbohydrate metabolism, calcium absorption, and blood sugar regulation. Manganese is also necessary for normal brain and nerve function.

The recommended dietary allowance (RDA) for manganese is 2.3 mg per day for adult men and 1.8 mg per day for adult women. Good food sources of manganese include nuts, seeds, legumes, whole grains, green leafy vegetables, and tea.

In some cases, exposure to high levels of manganese can cause neurological symptoms similar to Parkinson's disease, a condition known as manganism. However, this is rare and usually occurs in people who are occupationally exposed to manganese dust or fumes, such as welders.

Antioxidants are substances that can prevent or slow damage to cells caused by free radicals, which are unstable molecules that the body produces as a reaction to environmental and other pressures. Antioxidants are able to neutralize free radicals by donating an electron to them, thus stabilizing them and preventing them from causing further damage to the cells.

Antioxidants can be found in a variety of foods, including fruits, vegetables, nuts, and grains. Some common antioxidants include vitamins C and E, beta-carotene, and selenium. Antioxidants are also available as dietary supplements.

In addition to their role in protecting cells from damage, antioxidants have been studied for their potential to prevent or treat a number of health conditions, including cancer, heart disease, and age-related macular degeneration. However, more research is needed to fully understand the potential benefits and risks of using antioxidant supplements.

Nitroso compounds are a class of chemical compounds that contain a nitroso functional group, which is composed of a nitrogen atom bonded to an oxygen atom with a single covalent bond. The general formula for nitroso compounds is R-N=O, where R represents an organic group such as an alkyl or aryl group.

Nitroso compounds are known to be reactive and can form under various physiological conditions. They have been implicated in the formation of carcinogenic substances and have been linked to DNA damage and mutations. In the medical field, nitroso compounds have been studied for their potential use as therapeutic agents, particularly in the treatment of cancer and cardiovascular diseases. However, their use is limited due to their potential toxicity and carcinogenicity.

It's worth noting that exposure to high levels of nitroso compounds can be harmful to human health, and may cause respiratory, dermal, and ocular irritation, as well as potential genotoxic effects. Therefore, handling and storage of nitroso compounds should be done with caution, following appropriate safety guidelines.

"Nuclear Magnetic Resonance and Electron Spin Resonance Spectroscopy". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim ... Fluorine atoms have nine electrons, one fewer than neon, and electron configuration 1s22s22p5: two electrons in a filled inner ... "Certain nuclei can for many purposes be thought of as spinning round an axis like the Earth or like a top. In general the spin ... It also has a high electron affinity, second only to chlorine, and tends to capture an electron to become isoelectronic with ...
Gray, R., & Stevenson, M. H. (1989). Detection of irradiated deboned turkey meat using electron spin resonance spectroscopy. ... Using Electron Spin Resonance (ESR) Spectroscopy and Estimation of Applied Dose Using Re‐irradiation: Results of an In‐House ... Stewart, E. M., Stevenson, M. H., & Gray, R. (1994). Use of ESR spectroscopy for the detection of irradiated Crustacea. Journal ... Stewart, E. M., Stevenson, M. H., & Gray, R. (1991). Use of esr spectroscopy for the detection of irradiated whiting ( ...
In both cases, trimethylenemethane was detected by electron spin resonance spectroscopy. Trimethylenemethane has been obtained ... with one excited electron; and a quintet state, 5B2 (7.17 eV), with the p orbitals occupied by single electrons and D3h ...
He achieved his Masters degree in electron spin resonance spectroscopy in 1961. He spent two years as a teaching Fellow at ...
"RSC ESR Group - Electron Spin Resonance Spectroscopy Group of the Royal Society of Chemistry". Retrieved 2020-11-16. Cai, ... Christiane Renate Timmel is a German chemist who is Director of the Centre for Advanced Electron Spin Resonance at the ... Timmel was awarded the Tilden Prize on 2020 by the Royal Society of Chemistry for her contributions to electron-spin resonance ... Beyond her leadership of CAESR, Timmel chairs the Royal Society of Chemistry Electron Spin Resonance group. In 2020 Timmel was ...
She did research in the field of absorption, electron spin resonance and Mößbauer spectroscopy. The mineral Abswurmbachite is ...
... of interactions between proteins using site-directed spin labeling and electron paramagnetic resonance spectroscopy." Methods ...
She developed electron paramagnetic spectroscopy and other electron resonance techniques to understand spin effects during ... She has proposed that carbon nanotubes with highly confined electron spins could be used as qubits with record long coherence ... permitting quantitive analysis using electron paramagnetic resonance. ... electron transfer.[citation needed] In 2009, she was awarded the Association for Women in Science Innovator Award, and she was ...
... known for his work on infrared spectroscopy and electron spin resonance spectroscopy. Fred Zain, 51, American forensic ...
Owston wrote an article in New Scientist on the use of electron spin resonance spectroscopy in chemistry. Ouston, Roger J. ( ... ISBN 978-3-540-46128-9. Owston, P. G. (5 November 1964). "Electron Spin Resonance". New Scientist. 24 (416): 373-377. v t e ( ...
A. Kalachyk; I. Ugolev; T. Zabello; E. Oganova; V. Muravsky (2014-01-01). "Electron spin resonance spectroscopy of serum ... Kazmierczak, S. C.; Gurachevsky, A.; Matthes, G.; Muravsky, V. (2006-09-21). "Electron Spin Resonance Spectroscopy of Serum ... Kalachyk, A.; Ugolev, I.; Zabello, T.; Voitovich, V. (2014). "Electron Spin Resonance Spectroscopy of Albumin Transport Quality ... "Cancer-Associated Alteration in Fatty Acid Binding to Albumin Studied by Spin-Label Electron Spin Resonance". Cancer ...
... (EPR) or electron spin resonance (ESR) spectroscopy is a method for studying materials that ... Electric dipole spin resonance Ferromagnetic resonance Dynamic nuclear polarisation Spin label Site-directed spin labeling Spin ... Pulsed electron paramagnetic resonance could be advanced into electron nuclear double resonance spectroscopy (ENDOR), which ... spin resonance occurs near 9388.2 MHz for an electron compared to only about 14.3 MHz for 1H nuclei. (For NMR spectroscopy, the ...
... pioneering physical chemist who worked on nuclear magnetic resonance, electron spin resonance, and the microwave spectroscopy ... "for his researches concerning the resonance absorption of gamma radiation and his discovery in this connection of the effect ... "for his contributions to the theory of electron transfer reactions in chemical systems"; Wolf Prize winner; National Medal of ... pioneer in quantum optics and nonlinear laser spectroscopy, particularly advanced techniques in the study of laser induced ...
Organic Framework Compound MIL-53 As Studied by Electron Spin Resonance Spectroscopy". The Journal of Physical Chemistry C. 114 ... "A Continuous-Wave Electron Paramagnetic Resonance Study of Carbon Dioxide Adsorption on the Metal-Organic Frame-Work MIL-53". ... via the electron paramagnetic resonance spectrum of V IV dopant ions". Physical Chemistry Chemical Physics. 19 (36): 24545- ... Applied Magnetic Resonance. 45 (3): 269-285. doi:10.1007/s00723-014-0518-6. ISSN 0937-9347. S2CID 94965421. Mendt, Matthias; ...
Carrington's earlier contributions to chemical physics were in the fields of electron spin resonance (esr) spectroscopy, and ... Much of this work is reviewed in the classic monograph authored with John M Brown, "Rotational Spectroscopy of Diatomic ... This work on the spectroscopy of simple molecular ions provided accurate measurements with which theoretical calculations could ... Softley, Timothy P. (1984). Infrared predissociation spectroscopy of diatomic atoms. jisc.ac.uk (PhD thesis). University of ...
... with fluorescent or paramagnetic labeling groups can be employed in fluorescence spectroscopy and electron spin resonance ... Electron microscopy studies on bacteriorhodopsin, reconstituted in saturated and unsaturated fluid PC bilayers with varying ... In recent years, great advances in X-ray crystallography and electron microscopy techniques have yielded new insights of the ...
... to form stable paramagnetic nitroxide radicals that can be detected and analyzed by electron spin resonance spectroscopy. It is ... It is a blue liquid that is used in chemical research as a spin trap, i.e. it binds to radicals. t-BuNO is prepared by the ... David P. Barr; Michael R. Gunther; Leesa J. Deterding; Kenneth B. Tomer; Ronald P. Mason (1996). "ESR Spin-trapping of a ... It can be used as a spin trap. This molecule traps unstable free radicals ...
He specialized in electron spin resonance (ESR) spectroscopy and his dissertation was on nuclear resonance and electron spin ... and received his habilitation in 1977 with a thesis on dynamic NMR spectroscopy and electrochemistry. In 1979, he became ... resonance spectroscopic studies on bridged annulenes. He completed post-doctoral studies at the ETH Zurich under Jean François ...
... particularly to the understanding of nuclear spin-spin coupling and electron spin resonance spectroscopy. The Karplus equation ... He has also been influential in nuclear magnetic resonance spectroscopy, ... Together they wrote a computer program that modeled the atomic nuclei and some electrons of a molecule using classical physics ... describing the correlation between coupling constants and dihedral angles in proton nuclear magnetic resonance spectroscopy is ...
... electron spin resonance spectroscopy, magnetic resonance imaging (MRI) and Mössbauer spectroscopy. It may also be utilized to ... the so-called Minnaert resonance. The Minnaert resonance or Minnaert frequency is the acoustic resonance frequency of a single ... In 1925, Dutch physicists George Eugene Uhlenbeck and Samuel Goudsmit co-discovered the concept of electron spin, which posits ... The Zeeman effect is important in applications such as nuclear magnetic resonance spectroscopy, ...
... aka electron spin resonance) spectroscopy. He is the Frank and Robert Laughlin Professor of Physical Chemistry, emeritus, at ... In 2001, Freed founded the National Biomedical Center for Advanced Electron Spin Resonance Technology (ACERT) funded by ... 1981 Bruker Award in Electron Spin Resonance by the Royal Society of Chemistry, 1990 Fellow of the American Academy of Arts and ... Jack H. Freed (born April 19, 1938) is an American chemist known for his pioneering work in electron paramagnetic resonance ( ...
... for electron spin resonance spectroscopy or for magnonics. Coplanar waveguide resonators have also been employed to ... 2015). "Observing electron spin resonance between 0.1 and 67 GHz at temperatures between 50 mK and 300 K using broadband ... Another application of coplanar waveguides in solid state research is for studies involving magnetic resonance, e.g. ...
... electron spin resonance spectroscopy, magnetic resonance imaging (MRI) and Mössbauer spectroscopy. It may also be utilized to ... of nanomagnets is used for electrical operation of electron spins in quantum dots through electric dipole spin resonance, and ... It was called "anomalous" because the electron spin had not yet been discovered, and so there was no good explanation for it at ... The Zeeman effect is very important in applications such as nuclear magnetic resonance spectroscopy, ...
"Continuous Wave and Pulsed Electron Spin Resonance Spectroscopy of Paramagnetic Framework Cupric Ions in the Zn(II) Doped ...
... and a PhD degree in 1964 for research into electron spin resonance spectroscopy, and other aspects of theoretical chemistry. ...
... a magnetic resonance technique analogous to nuclear magnetic resonance (NMR) or electron spin resonance (ESR) spectroscopy. ... p. 4. ISBN 978-0-521-24241-7. J.H. Brewer (1994). "Muon Spin Rotation/Relaxation/Resonance". Encyclopedia of Applied Physics. ... Although muonium is short-lived, physical chemists study it using muon spin spectroscopy (μSR), ... Muonium is usually studied by muon spin rotation, in which the Mu atom's spin precesses in a magnetic field applied transverse ...
... magnetic resonance spectroscopy MeSH H01.671.579.631.240 - electron spin resonance spectroscopy MeSH H01.671.579.631.550 - ... electrons MeSH H01.671.579.404.467 - heavy ions MeSH H01.671.579.404.600 - mesons MeSH H01.671.579.404.645 - neutrons MeSH ... biomolecular nuclear magnetic resonance MeSH H01.671.579.694 - nuclear reactors MeSH H01.671.579.705 - particle accelerators ...
Spectroscopic techniques like NMR, spin label electron spin resonance, Raman spectroscopy, infrared spectroscopy, circular ... Protein dynamics can be observed by neutron spin echo spectroscopy. Conformational change in structure can be measured using ... Fluorescent imaging techniques, as well as electron microscopy, X-ray crystallography, NMR spectroscopy, atomic force ... Dual-polarization interferometry and circular dichroism Electron paramagnetic resonance (EPR) European Biophysical Societies' ...
Nanoscale Spin Imaging Marina Bennati - Electron-Spin Resonance Spectroscopy Bert L. de Groot - Computational Biomolecular ... nuclear magnetic resonance spectroscopy and tomography, mass spectrometry, optical spectroscopy, or atomistic computer ... In 1971, the MPI for Physical Chemistry merged with the MPI for Spectroscopy (also in Göttingen), forming the MPI for ... Jens Frahm and his coworkers invented a rapid acquisition technique for magnetic resonance imaging termed FLASH MRI (fast low ...
... magnetic resonance spectroscopy MeSH E05.196.867.519.274 - electron spin resonance spectroscopy MeSH E05.196.867.519.550 - ... spectroscopy, electron energy-loss MeSH E05.196.867.838.500 - microscopy, energy-filtering transmission electron MeSH E05.196. ... electron probe microanalysis MeSH E05.595.402.541 - microscopy, electron, scanning MeSH E05.595.402.580 - microscopy, electron ... spectroscopy, mossbauer MeSH E05.196.867.800 - spectrometry, x-ray emission MeSH E05.196.867.800.360 - electron probe ...
... spectroscopy. Electron Paramagnetic Resonance spectroscopy Electron Spin Resonance spectroscopy Principles of EMR spectroscopy ... ESR Spectroscopy â ¢ Electron Spin Resonance Spectroscopy â ¢ Also called EPR Spectroscopy â Electron Paramagnetic Resonance ... Electron Spin Resonance Spectroscopy or Itâ s fun to flip electrons! Since the magnetic field interacts with the spin, the spin ... Electron paramagnetic resonance (EPR) spectroscopy also known as electron spin resonance (ESR) spectroscopy has been used to ...
Spin Labels in Electron Spin Resonance (ESR) Spectroscopy In ESR, a spin label is added to the target site using cysteine ...
To achieve that goal, spin labelling specific for glycosylation sites in combination with EPR spectroscopy was utilized to ... The present thesis deals with the development and application of EPR spectroscopy for the detection and quantitative study of ... O-GlcNAcylated proteins in cooperation with bioortogonal nitroxide spin-labeling (SL) was utilized to enable mapping of O- ... approach was used to investigate the sugar moieties with corresponding chemical reporters prone for further spin labelling. ...
We have undertaken electron paramagnetic resonance and spin trapping investigations of the photochemistry of kynurenine (KN), a ... Electron Spin Resonance Spectroscopy* * Electron Transport * Eye / metabolism * Free Radicals / metabolism * Humans ... We have undertaken electron paramagnetic resonance and spin trapping investigations of the photochemistry of kynurenine (KN), a ... Free radical reactions photosensitized by the human lens component, kynurenine: an EPR and spin trapping investigation Free ...
"Nuclear Magnetic Resonance and Electron Spin Resonance Spectroscopy". Ullmanns Encyclopedia of Industrial Chemistry. Weinheim ... Fluorine atoms have nine electrons, one fewer than neon, and electron configuration 1s22s22p5: two electrons in a filled inner ... "Certain nuclei can for many purposes be thought of as spinning round an axis like the Earth or like a top. In general the spin ... It also has a high electron affinity, second only to chlorine, and tends to capture an electron to become isoelectronic with ...
Electron spin resonance spectroscopy. *Membrane transport mechanisms. *Membrane biogenesis. *In-situ / cellular structural ...
Electron Spin Resonance Spectroscopy: A brief review of theory. Analysis of ESR spectra of systems in liquid phase, radicals ... Nuclear Magnetic Resonance Spectroscopy: Introduction. Application of 1H and 13C NMR spectroscopy including COSY, NOESY, NOE ... Electron Paramagnetic Resonance, Elementary Theory and Practical Applications, Weil, John A, J. R. Bolton, and Wertz, J. E, ... X-Ray Photo-Electron Spectroscopy: Physical concepts. Application to determine atomic charges, oxidation numbers, catalyst ...
electron spin resonance spectroscopy (1) * embryos (1) * endothelial cells (1) * eyes (1) ...
Anistropic exchange interactions in CuGeO3 probed by electron spin resonance spectroscopy Physical Review B 68, 014417 (2003) ... Electron spin resonance investigation of the Heavy-Fermion compound CeCu2(Si1−xGex)2 Applied Magnetic Resonance 12, 287-298 ( ... Spin fluctuations in the quasi-two-dimensional Heisenberg ferromagnet GdI2 studied by electron spin resonance Physical Review B ... Strong reduction of the Korringa relaxation in the spin-density wave regime of EuFe2As2 observed by electron spin resonance ...
Electron spin resonance (ESR) is a powerful spectroscopy method which allows to identify and characterize paramagnetic species ... Because of the weak spin-microwave coupling, conventional ESR spectroscopy has a low sensitivity. Recent experiments have ... It usually relies on detecting microwave radiation absorbed or emitted by the spins into a microwave resonator tuned to their ... However, these demonstrations have been realized in very restrictive conditions, using well-known spin systems. To probe ...
Detection of reactive oxygen species in isolated, perfused lungs by electron spin resonance spectroscopy. Respir Res 2005; 6: ... which transfers the second electron to cytochrome b of complex III but is also prone to release the electron instead to ... Ubisemiquinone is the electron donor for superoxide formation by complex III of heart mitochondria. Arch Biochem Biophys 1985; ... It is generally accepted that simple inhibition of complex IV and electron backup is not sufficient for ROS production at the ...
This leads to a reorganization of its electron structure which can be detected by electron spin resonance spectroscopy. ... Electron spin resonance spectroscopy can be used to measure complexes of metal ions with the free -SH groups. In experiments ... Electron spin resonance spectroscopy was used to measure the antioxidant power (AP) of KeraGuard. This technique is used to ... Electron spin resonance spectroscopy was also used to demonstrate an antioxidant protection effect on hair. UV irradiation of ...
In vivo experiments demonstrate that these nanocapsules can target to tumor sites through fluorescence/magnetic resonance ... Electron spin resonance (ESR) spectroscopy further confirmed the potential of the ICG@Fe/FeO-PPP nanocapsules to act as a ... c ESR spectra of Fe/FeO NCs and ICG@Fe/FeO-PPP nanocapsules with DMPO as the spin trap in different pH values condition (7.4, ... 2b). The presence of satellite peaks in the high-resolution X-ray photoelectron spectroscopy (XPS) of Fe 2p shown in Fig. 2f ...
Electron spin resonance (ESR) spectroscopy is one of the few-experimental methods, offering direct access to both T1 and T2 of ... field swept electron spin echo (FS ESE), pulsed electron nuclear double resonance (ENDOR) and four-pulse electron spin echo ... Electron Spin Resonance Spectroscopy of Single- Walled Carbon-Nanotube Thin-Films and their Transistors Page: 130-146 (17). ... Here we review electron spin resonance (ESR) spectroscopy of semiconductor single-walled CNT (SW-CNT) thin films and their ...
Phenolics in Moroccan Medicinal Plant Species as Studied by ElectronSpin Resonance Spectroscopy. Pharmaceutical Biology 2001;39 ...
Detection of Nitric Oxide and Superoxide Radical Anion by Electron Paramagnetic Resonance Spectroscopy from Cells using Spin ...
Nuclear magnetic resonance, electron spin (paramagnetic) resonance spectroscopy: Principles (systems with magnetic moments, ... Raman spectroscopy: Principles (non-elastic scattering of radiation, changes of vibration and rotation energy of molecules). ... Radiation emission (electron microanalysis), absorption, fluorescence, difraction. Experimental set- up in individual methods. ... Molecular absorption spectrometry in infrared range of radiation (vibration and rotation spectroscopy): Principles. ...
Hydroxyl radicals as intermediates studied by spin trapping and electron spin resonance spectroscopy. AM Faure, ML Andersen, L ...
81. E. Meirovich, Z. Luz and J.A. Kalb (Gilboa), Electron spin resonance spectroscopy of single crystals of concanavalin A. J. ... 82. E. Meirovich, Z. Luz and J.A. Kalb (Gilboa), Electron spin resonance spectroscopy of aqueous solutions of concanavalin A. J ... 124. E. Meirovitch, Z. Luz and H. Zimmermann, Electron Spin Resonance study of nitroxide spin probes dissolved in the discotic ... studied by electron spin resonance spectroscopy. Molec. Phys., 30, 1589 (1975).. 86. A. Baram, Z. Luz and S. Alexander, Powder ...
103) Weckhuysen, B. M.; Heidler, R.; Schoonheydt, R. A. Electron Spin Resonance Spectroscopy. Mol. Sieves 2004, 4, 295-335.. ( ... 104) Janzen, E. G.; Blackburn, B. J. Detection and Identification of Short-Lived Free Radicals by an Electron Spin Resonance ... Detection of High-Frequency Ultrasound-Induced Singlet Oxygen by the ESR Spin-Trapping Method. Chem. Lett. 2013, 42, 1291-1293. ...
Photoelectron spectroscopy. tesfayehh•27.4K. visualizações. Electron Spin Resonance Spectroscopy Saiva Bhanu Kshatriya College ... v) In case of odd N or odd Z (or both) nuclides, the nuclear properties like spin, parity and magnetic moment are due to the ... 21 raman spectroscopy introductionShri Shivaji Science College Amravati. 320. visualizações•23. slides ... v) Nuclear force is independent of charge and spin of the nucleons. vi) Behavior of nucleus is comparable to that of a liquid ...
Hydroxyl free radical reactions with amino acids and proteins studied by electron spin resonance spectroscopy and spin-trapping ...
... and actomyosin was examined by electron spin resonance spectroscopy coupled with spin trapping. O2− was provided by the ... The interaction of (+)-catechin with a lipid bilayer was examined by the spin probe method. The spin probe, 2,2,6,6- ... The rotational correlation time of a spin probe 16-doxylstearic acid and the order parameter of 5-doxylstearic acid in the ... Interaction of (+)-Catechin with a Lipid Bilayer Studied by the Spin Probe Method ...
Belkin S, Packer L. Determination of pH gradients in intact cyanobacteria by electron spin resonance spectroscopy. Methods ...
X-ray diffraction (XRD), Electron spin resonance (ESR) spectroscopy, ATR-FTIR spectroscopy, and Thermogravimetric Analysis (TGA ... Near Infrared (NIR) spectroscopy is available at the Department of Viticulture and Wine Sciences, Faculty of AgriSciences.​ ... liquid and solid state NMR spectroscopy, ​DNA-sequencing, CT-Scanner, SEM and AFM microscopes. ...
... site-directed spin probe labeling with electron spin resonance spectroscopy, to test our model for how two GαT subunits ... We determined structures for the rhodopsin-transducin complex by cryo-electron microscopy (cryoEM), which together with efforts ...
... the National Resource for Advanced Electron-Spin Resonance Spectroscopy, at Cornell. His research areas include high field ... electron paramagnetic resonance and quasioptical design techniques.. Cristian Lenart is Professor and Chair of Mathematics and ...
Electron spin resonance (ESR) spectroscopy then made it possible to quantify the environmentally persistent free radicals in ...
... which is based on the detection of radiation-induced free radicals in alanine by means of electron spin resonance (ESR) ... spectroscopy, are well known for irradiations in the 60Co reference field [1]. To be able to use the system also in the ... alanine dosimeter probes were irradiated in the electron linear accelerator - and this by means of ultrahard photon radiation. ...
... spectroscopy and electron-nuclear double resonance (ENDOR) experiments. One could thus obtain a detailed insight into the ... preparations in frozen solution and in single crystals were investigated by various techniques of Electron Spin Resonance (ESR ...
  • Electron Spin Resonance (ESR) or Electron paramagnetic resonance Spectroscopy (EPR): powerful non-destructive magnetic resonance spectroscopic technique Used to analyse substance with one or more unpaired electrons and radicals Invented by Zavoiskii in 1944 Similar to Nuclear magnetic resonance (NMR) This technique offers detailed atomistic insights into the properties of the species, such as geometric and electronic structure or chemical environment. (hospedagemdesites.ws)
  • We sampled blood for oxidative (electron paramagnetic resonance spectroscopy, HPLC), nitrosative (ozone‐based chemiluminescence) and inflammatory (fluorescence) biomarkers. (southwales.ac.uk)
  • Electron spin interaction, E diagram Pulsed Electron-Electron Double Resonance (PELDOR) pulse sequence February 7, 2018 Applications of dipolar spectroscopy to macromolecular complexes 4-pulse DEER sequence, DQ-EPR, SIFTER pulse sequences, Multi-spin effects Calculate the distance between pair of spin labels, Calculate the number of coupled spins Here, the electron Spin resonance spectroscopy (EPR) or sometimes known as electron spin resonance (ESR) will be discussed. (hospedagemdesites.ws)
  • Double resonance stechniques: ENDOR in liquid solution, ENDOR in powers and non-oriented solids. (iitk.ac.in)
  • Designs of CW and pulse Electron Nuclear Double Resonance (ENDOR) spectrometers, which are very important techniques for studying precisely hyperfine interactions and local environment of paramagnetic ions in carbon-based materials are included. (benthamscience.com)
  • Protein preparations in frozen solution and in single crystals were investigated by various techniques of Electron Spin Resonance (ESR) spectroscopy and electron-nuclear double resonance (ENDOR) experiments. (scheringstiftung.de)
  • Elemental Analysis (CNSH), Anions analysis via ion chromatography (IC), ​X-ray Fluorescence Spectometer (XRF)​, ICP-MS and ICP-AES, mass spectrometry, liquid and solid state NMR spectroscopy, ​DNA-sequencing, CT-Scanner, SEM and AFM microscopes. (sun.ac.za)
  • Electron spin resonance (ESR) spectroscopy then made it possible to quantify the environmentally persistent free radicals in the studied material and to identify their adjacent chemical structures. (swansea.ac.uk)
  • The properties of the secondary standard measuring system, which is based on the detection of radiation-induced free radicals in alanine by means of electron spin resonance (ESR) spectroscopy, are well known for irradiations in the 60 Co reference field [1]. (ptb.de)
  • Nuclear Magnetic Resonance Spectroscopy: Introduction. (iitk.ac.in)
  • Carbon-13 Nuclear Magnetic Resonance Spectroscopy, G. C. Levy, R. L. Lichter and G. L. Nelson, Wiley, 1980. (iitk.ac.in)
  • 4. Z. Luz and B.L. Silver, The acid catalyzed exchange of phosphorus bonded hydrogen in aqueous solutions of dialkyl phosphonates studied by nuclear magnetic resonances. (weizmann.ac.il)
  • 7. M. Sheinblatt and Z. Luz, Hydrogen exchange in benzylmercaptan studied by nuclear magnetic resonance. (weizmann.ac.il)
  • 9. Z. Luz and S. Meiboom, Nuclear magnetic resonance study of the protolysis of trimethylammonium ion in aqueous solution-order of the reaction with respect to water. (weizmann.ac.il)
  • 11. Z. Luz and S. Meiboom, Nuclear magnetic resonance study of the solvation of Co++ in methanol-water mixtures. (weizmann.ac.il)
  • 14. Z. Luz, Nuclear magnetic resonance and optical spectroscopy of [Co(MeOH)5Cl]+ in methanol and the kinetics of methanol exchange of the solvation shell. (weizmann.ac.il)
  • 15. Z. Luz, Nuclear magnetic resonance study of cobalt-chlorine complexes in methanol. (weizmann.ac.il)
  • 19. I. Pecht and Z. Luz, Oxygen exchange between periodate and water studied by 17O nuclear magnetic resonance. (weizmann.ac.il)
  • 21. Z. Luz and G. Yagil, Water 17O nuclear magnetic resonance shift in aqueous solutions of 1:1 electrolyte. (weizmann.ac.il)
  • 22. Z. Luz and B.L. Silver, The acid catalyzed oxygen exchange of acetyl-acetone in dioxane-water solution measured by oxygen-17 nuclear magnetic resonance. (weizmann.ac.il)
  • 23. B.L. Silver, Z. Luz, S. Peller and J. Reuben, Intramolecular hydrogen bonding in the hydrogen anions of some carboxylic acids in water-methanol mixtures, Evidence from nuclear magnetic resonance. (weizmann.ac.il)
  • 24. Z. Luz and I. Pecht, Oxygen-17 nuclear magnetic resonance and oxygen exchange in aqueous solutions of telluric acid. (weizmann.ac.il)
  • 28. Z. Luz, B.L. Silver and D. Fiat, O-17 nuclear magnetic resonance of manganese (III) tris(acetyacetonate). (weizmann.ac.il)
  • 29. P. Greenzaid, Z. Luz and D. Samuel, A nuclear magnetic resonance study of the reversible hydration of aliphatic aldehydes and ketones. (weizmann.ac.il)
  • This intermolecular contribution to hydrogen-bond geometry in a quantitative way even for to the shielding tensor is due to induced electronic currents in condensed phases.8-12 To fully capitalize on these theoretical nearby molecules and to the perturbing effect of intermolecular advances, one would like to experimentally determine the interactions on the electron distribution and nuclear geometry shielding anisotropy in liquids. (lu.se)
  • 85Rb), arising from the interaction of the magnetic field created by the orbiting electrons and the magnetic moment due to the nuclear spin. (lu.se)
  • Figure 1 shows the hyperfine structure in the 2 levels in 87Rb, where the nuclear spin is I = 3/2. (lu.se)
  • In particular, they are and nuclear magnetic resonance (NMR) refinement. (lu.se)
  • X -ray diffraction (XRD), Electron spin resonance (ESR) spectroscopy, ATR- FTIR spectroscopy, and Thermogravimetric Analysis (TGA) are available at the Departments of Chemistry and Physics, Faculty of Nature Sciences. (sun.ac.za)
  • Extensive characterization including infrared and X-ray spectroscopy, thermogravimetric analysis, size, charge, surface area, and density captured the alteration in physicochemical properties as the material went through sequential purification. (cdc.gov)
  • Fluorescence spectroscopy: Fluorescence energy transfer and its applications to measurement of distances in molecules. (iitk.ac.in)
  • In vivo experiments demonstrate that these nanocapsules can target to tumor sites through fluorescence/magnetic resonance imaging and offer remarkable therapeutic results. (nature.com)
  • Hyperfine spectroscopies, ESEEM, ENDOR and HYSCORE, determined the electron hyperfine couplings of unpaired electrons with magnetic nuclei, thus allowing the evaluation of the extent of the π-system and the presence of different types of nuclei. (benthamscience.com)
  • For example, Langmuir techniques, Brewster angle microscopy (BAM), 2D electrochemical methods, and electron spin resonance spectroscopy are used to study lateral mobility of lipids at the air/water interface in order to understand physical properties of lipid monolayers and to probe the water liquid-vapor interfacial region. (berkeley.edu)
  • Our analysis of the EPR spectra considers the presence of three types of paramagnetic contributions: conduction electrons, edge states and molecular states. (benthamscience.com)
  • Non-collinear magnetic structure induces emergent magnetic field on conduction electrons, resulting in such as a geometrical Hall effect and so on [1]. (mrs.org)
  • Electron Paramagnetic Resonance (EPR), also called Electron Spin Resonance (ESR), is a branch of magnetic resonance spectroscopy which utilizes microwave radiation to probe species with unpaired electrons, such as radicals, radical cations, and triplets in the presence of an externally applied static magnetic field. (hospedagemdesites.ws)
  • To achieve that goal, spin labelling specific for glycosylation sites in combination with EPR spectroscopy was utilized to probe glycoprotein structural changes under O-glycosylation. (uni-konstanz.de)
  • and scanning electron or probe microscopies. (beloit.edu)
  • The shielding tensor can thus be used measurements of spin relaxation rates, which, through their as a probe of intermolecular structure and interactions in liquids second-order dependence on the spin Hamiltonian, contain and solids. (lu.se)
  • X-ray photoemission spectroscopy detected increased surface oxygen contents on particles in co-exposure aerosols. (cdc.gov)
  • We use time-resolve photoemission electron microscopy (TR-PEEM), where fs time resolution is provided by fs pulses and spatial resolution is provided by PEEM to investigate charge carrier dynamics in semiconductor and plasmonic nanomaterials. (lu.se)
  • Electron spin resonance (ESR) spectroscopy is also known as Electron paramagnetic resonance (EPR) It is absorption spectroscopy similar to NMR. (hospedagemdesites.ws)
  • Fluorine atoms have nine electrons, one fewer than neon, and electron configuration 1s22s22p5: two electrons in a filled inner shell and seven in an outer shell requiring one more to be filled. (wikipedia.org)
  • Fluorine's first ionization energy is third-highest among all elements, behind helium and neon, which complicates the removal of electrons from neutral fluorine atoms. (wikipedia.org)
  • In general, the computational load rises rapidly with the number of atoms and electrons considered and therefore, only rather small systems can be studied accurately. (lu.se)
  • 3. B.L. Silver and Z. Luz, Rates and mechanisms of protolysis of trimethyl-phosphonium ion in aqueous solution studied by proton magnetic resonance. (weizmann.ac.il)
  • 20. Z. Luz and R.G. Shulman, Proton magnetic resonance shifts in aqueous solutions of paramagnetic metal ions. (weizmann.ac.il)
  • We are interested in understanding how composition and structure of monolayer assemblies affect the dynamics of such processes as long range electron tunneling, lateral molecular diffusion and vectorial proton transport. (berkeley.edu)
  • by measuring the proton spin relaxation rate as a function of magnetic induction field in a water sample where dipole-dipole couplings are suppressed by H/D isotope dilution. (lu.se)
  • The present thesis deals with the development and application of EPR spectroscopy for the detection and quantitative study of the protein O-linked glycosylation modification. (uni-konstanz.de)
  • Spin-detection in volume-limited samples has applications ranging from solid-state physics to structural biology. (nist.gov)
  • Magnetic resonance spectroscopies based on inductive detection are powerful and versatile techniques that can provide atomic-level structural and functional information about a wide range of samples under broadly variable conditions. (nist.gov)
  • for example, inductive-detection electron paramagnetic resonance (EPR) spectroscopy currently requires sample volumes on the order of tens of microliters. (nist.gov)
  • Spin-orbit interaction in combination with structural inversion asymmetry on magnetic surfaces, interfaces, hetero- and nanostructures is a source for a variety of spin-dependent transport phenomena and novel magnetic textures, with the chiral magnetic skyrmions [1] being the best known. (mrs.org)
  • Interaction of a high-intensity optical laser beam with a solid target can generate `hot' electrons, which generate radiation hazards (mainly bremsstrahlung photons and neutrons) from interaction of hot electrons with target and the surrounding materials. (lu.se)
  • In one of the most fundamental experiments on the structure of matter, Stern and Gerlach showed that an atom with a net electron magnetic moment can take up only discrete orientations in a magnetic field. (hospedagemdesites.ws)
  • The purpose of this laboratory exercise is to illustrate how we may investigate tiny energy splittings in an atomic system using laser spectroscopy. (lu.se)
  • Indeed, building on the expertise, methods and infrastructure used in that research, our faculty's continued to explore novel phenomenology in condensed matter, and our efforts were rewarded in 2007 with a groundbreaking discovery when the Molenkamp group demonstrated the Quantum Spin Hall Effect in a HgTe heterostructure, the first experimental realization of a topological insulator. (uni-wuerzburg.de)
  • 133. S.A. Zvyagin, Spin dynamics in quantum sine-Gordon chains: high-field ESR studies, Appl. (hzdr.de)
  • Planar microresonators are fabricated in the NIST Nanofab, tested in our laboratory, and incorporated into a commercial 9 GHz or NIST-built 34 GHz electron paramagnetic resonance (EPR) spectrometer for measurements of thin films and other volume-limited samples. (nist.gov)
  • In ESR, a spin label is added to the target site using cysteine substitution. (news-medical.net)
  • possible only with molecules having unpaired electrons Instead of Radiowaves in NMR, Microwaves is used in ESR. (hospedagemdesites.ws)
  • Iron exists in numerous forms in water and is commonly bonded or co-ordinated to other species such as water molecules or electron donor partners (Johnson et al 2007). (europa.eu)
  • The electron spin resonance spectrum of a free radical or coordination complex with one unpaired electron is the simplest of all forms of spectroscopy. (hospedagemdesites.ws)
  • Spin traps allow characterization of unstable radical species using electron spin resonance spectroscopy. (etsu.edu)
  • Electron paramagnetic resonance (EPR) spectroscopy also known as electron spin resonance (ESR) spectroscopy has been used to characterize paramagnetic surface species for a long time. (hospedagemdesites.ws)
  • Electron spin resonance (ESR) is a powerful spectroscopy method which allows to identify and characterize paramagnetic species. (ens-lyon.fr)
  • Compared with individual exposures, co-exposure aerosols produced greater acellular and cellular oxidants detected by electron paramagnetic resonance (EPR) spectroscopy, and in vivo immune-spin trapping (IST), as well as synergistically increased lavage neutrophils, lavage proteins and inflammation related gene/protein expression. (cdc.gov)
  • Analysis of EPR spectra, spin Hamiltonians, EPR lineshapes, evaluation of spin-Hamiltonian parameters, and simulation of single-crystal and powder spectra are also explained. (benthamscience.com)
  • We determined structures for the rhodopsin-transducin complex by cryo-electron microscopy (cryoEM), which together with efforts from other laboratories, led to a detailed picture of how GPCRs activate their G protein partners. (cornell.edu)
  • We apply photoluminescence (PL) microscopy and micro spectroscopy to rationalize the recombination pathways of free charge carriers at the conditions of constantly evolving defect types and concentrations. (lu.se)
  • Thus, the possibility of using melatonin as an in vivo spin trap can be determined. (etsu.edu)
  • The rest of the fluorite is converted into corrosive hydrogen fluoride en route to various organic fluorides, or into cryolite, which plays a key role in aluminium refining. (wikipedia.org)
  • It usually relies on detecting microwave radiation absorbed or emitted by the spins into a microwave resonator tuned to their Larmor precession frequency. (ens-lyon.fr)
  • This leads to a reorganization of its electron structure which can be detected by electron spin resonance spectroscopy. (cosmeticsdesign-europe.com)
  • For this purpose, a series of irradiations was carried out in PTB's reference fields: approximately at the same time as the calibration irradiation, alanine dosimeter probes were irradiated in the electron linear accelerator - and this by means of ultrahard photon radiation. (ptb.de)
  • Because of the weak spin-microwave coupling, conventional ESR spectroscopy has a low sensitivity. (ens-lyon.fr)