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.
The univalent radical OH. Hydroxyl radical is a potent oxidizing agent.
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.
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.
Inorganic compounds that contain the OH- group.
Complete or partial surgical removal of the prostate. Three primary approaches are commonly employed: suprapubic - removal through an incision above the pubis and through the urinary bladder; retropubic - as for suprapubic but without entering the urinary bladder; and transurethral (TRANSURETHRAL RESECTION OF PROSTATE).
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).
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.
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.
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.
Inorganic oxides that contain nitrogen.
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)
An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC
Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.
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.
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.
Used for excision of the urinary bladder.
Tumors or cancer of the PROSTATE.
Use of a pulse of X-rays or fast electrons to generate free radicals for spectroscopic examination.
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.
Total mastectomy with axillary node dissection, but with preservation of the pectoral muscles.
An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.
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.
Peroxides produced in the presence of a free radical by the oxidation of unsaturated fatty acids in the cell in the presence of molecular oxygen. The formation of lipid peroxides results in the destruction of the original lipid leading to the loss of integrity of the membranes. They therefore cause a variety of toxic effects in vivo and their formation is considered a pathological process in biological systems. Their formation can be inhibited by antioxidants, such as vitamin E, structural separation or low oxygen tension.
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 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.
Natural product isolated from Streptomyces pilosus. It forms iron complexes and is used as a chelating agent, particularly in the mesylate form.
A glycoprotein that is a kallikrein-like serine proteinase and an esterase, produced by epithelial cells of both normal and malignant prostate tissue. It is an important marker for the diagnosis of prostate cancer.
Electron-accepting molecules in chemical reactions in which electrons are transferred from one molecule to another (OXIDATION-REDUCTION).
Removal of the breast, pectoral muscles, axillary lymph nodes, and associated skin and subcutaneous tissue.
Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.
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.
Benzene derivatives that include one or more hydroxyl groups attached to the ring structure.
The rate dynamics in chemical or physical systems.
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.
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 tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.
Inorganic or organic compounds that contain divalent iron.
Inorganic or organic oxy acids of sulfur which contain the RSO2(OH) radical.
A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.
The application of electronic, computerized control systems to mechanical devices designed to perform human functions. Formerly restricted to industry, but nowadays applied to artificial organs controlled by bionic (bioelectronic) devices, like automated insulin pumps and other prostheses.
An enzyme isolated from horseradish which is able to act as an antigen. It is frequently used as a histochemical tracer for light and electron microscopy. Its antigenicity has permitted its use as a combined antigen and marker in experimental immunology.
The dialdehyde of malonic acid.
Physiologic methyl radical donor involved in enzymatic transmethylation reactions and present in all living organisms. It possesses anti-inflammatory activity and has been used in treatment of chronic liver disease. (From Merck, 11th ed)
Benzoate derivatives substituted by one or more hydroxy groups in any position on the benzene ring.
Temporary or permanent diversion of the flow of urine through the ureter away from the URINARY BLADDER in the presence of a bladder disease or after cystectomy. There is a variety of techniques: direct anastomosis of ureter and bowel, cutaneous ureterostomy, ileal, jejunal or colon conduit, ureterosigmoidostomy, etc. (From Campbell's Urology, 6th ed, p2654)
A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.
Myoglobin which is in the oxidized ferric or hemin form. The oxidation causes a change in color from red to brown.
A purine base found in most body tissues and fluids, certain plants, and some urinary calculi. It is an intermediate in the degradation of adenosine monophosphate to uric acid, being formed by oxidation of hypoxanthine. The methylated xanthine compounds caffeine, theobromine, and theophylline and their derivatives are used in medicine for their bronchodilator effects. (Dorland, 28th ed)
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
Methods which attempt to express in replicable terms the extent of the neoplasm in the patient.
A generic descriptor for all TOCOPHEROLS and TOCOTRIENOLS that exhibit ALPHA-TOCOPHEROL activity. By virtue of the phenolic hydrogen on the 2H-1-benzopyran-6-ol nucleus, these compounds exhibit varying degree of antioxidant activity, depending on the site and number of methyl groups and the type of ISOPRENOIDS.
Inorganic or organic compounds containing trivalent iron.
The local recurrence of a neoplasm following treatment. It arises from microscopic cells of the original neoplasm that have escaped therapeutic intervention and later become clinically visible at the original site.
Elements of limited time intervals, contributing to particular results or situations.
A photographic fixative used also in the manufacture of resins. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), this substance may reasonably be anticipated to be a carcinogen (Merck Index, 9th ed). Many of its derivatives are ANTITHYROID AGENTS and/or FREE RADICAL SCAVENGERS.
Surgical excision of one or more lymph nodes. Its most common use is in cancer surgery. (From Dorland, 28th ed, p966)
A procedure in which a laparoscope (LAPAROSCOPES) is inserted through a small incision near the navel to examine the abdominal and pelvic organs in the PERITONEAL CAVITY. If appropriate, biopsy or surgery can be performed during laparoscopy.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
A direct-acting oxidative stress-inducing agent used to examine the effects of oxidant stress on Ca(2+)-dependent signal transduction in vascular endothelial cells. It is also used as a catalyst in polymerization reactions and to introduce peroxy groups into organic molecules.
Compounds containing the -SH radical.
Excision of the uterus.
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.
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)
An analgesic and antipyretic that has been given by mouth and as ear drops. Antipyrine is often used in testing the effects of other drugs or diseases on drug-metabolizing enzymes in the liver. (From Martindale, The Extra Pharmacopoeia, 30th ed, p29)
Excision of kidney.
Low-molecular-weight end products, probably malondialdehyde, that are formed during the decomposition of lipid peroxidation products. These compounds react with thiobarbituric acid to form a fluorescent red adduct.
An oxyacid of chlorine (HClO) containing monovalent chlorine that acts as an oxidizing or reducing agent.
Compounds with a benzene ring fused to a thiazole ring.
Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.
Tumors or cancer of the URINARY BLADDER.
Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.
Organic chemicals that form two or more coordination links with an iron ion. Once coordination has occurred, the complex formed is called a chelate. The iron-binding porphyrin group of hemoglobin is an example of a metal chelate found in biological systems.
Sulfhydryl acylated derivative of GLYCINE.
A hemeprotein from leukocytes. Deficiency of this enzyme leads to a hereditary disorder coupled with disseminated moniliasis. It catalyzes the conversion of a donor and peroxide to an oxidized donor and water. EC
A gland in males that surrounds the neck of the URINARY BLADDER and the URETHRA. It secretes a substance that liquefies coagulated semen. It is situated in the pelvic cavity behind the lower part of the PUBIC SYMPHYSIS, above the deep layer of the triangular ligament, and rests upon the RECTUM.
Inorganic oxides of sulfur.
A saclike, glandular diverticulum on each ductus deferens in male vertebrates. It is united with the excretory duct and serves for temporary storage of semen. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Chemical reactions effected by light.
An excited state of molecular oxygen generated photochemically or chemically. Singlet oxygen reacts with a variety of biological molecules such as NUCLEIC ACIDS; PROTEINS; and LIPIDS; causing oxidative damages.
A potent oxidant synthesized by the cell during its normal metabolism. Peroxynitrite is formed from the reaction of two free radicals, NITRIC OXIDE and the superoxide anion (SUPEROXIDES).
Chemical bond cleavage reactions resulting from absorption of radiant energy.
A long-acting calcium-blocking agent with significant anti-anginal activity. The drug produces significant coronary vasodilation and modest peripheral effects. It has antihypertensive and selective anti-arrhythmia activities and acts as a calmodulin antagonist.
A fungistatic compound that is widely used as a food preservative. It is conjugated to GLYCINE in the liver and excreted as hippuric acid.
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A highly polar organic liquid, that is used widely as a chemical solvent. Because of its ability to penetrate biological membranes, it is used as a vehicle for topical application of pharmaceuticals. It is also used to protect tissue during CRYOPRESERVATION. Dimethyl sulfoxide shows a range of pharmacological activity including analgesia and anti-inflammation.
A flavonol glycoside found in many plants, including BUCKWHEAT; TOBACCO; FORSYTHIA; HYDRANGEA; VIOLA, etc. It has been used therapeutically to decrease capillary fragility.
A poisonous dipyridilium compound used as contact herbicide. Contact with concentrated solutions causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds.
Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
Hydrocarbon rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.
An enzyme catalyzing the oxidation of 2 moles of glutathione in the presence of hydrogen peroxide to yield oxidized glutathione and water. EC
A nucleoside consisting of the base guanine and the sugar deoxyribose.
A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms.
Benzene rings which contain two ketone moieties in any position. They can be substituted in any position except at the ketone groups.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
Involuntary loss of URINE, such as leaking of urine. It is a symptom of various underlying pathological processes. Major types of incontinence include URINARY URGE INCONTINENCE and URINARY STRESS INCONTINENCE.
A method for determining points of contact between interacting proteins or binding sites of proteins to nucleic acids. Protein footprinting utilizes a protein cutting reagent or protease. Protein cleavage is inhibited where the proteins, or nucleic acids and protein, contact each other. After completion of the cutting reaction, the remaining peptide fragments are analyzed by electrophoresis.
An antiseptic and disinfectant aromatic alcohol.
Structures which collect and store urine and are emptied by catheterization of a cutaneous stoma or internal diversion to the urethra. The reservoirs are surgically created during procedures for urinary diversion.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
An enzyme that catalyzes the deamination of ethanolamine to acetaldehyde. EC
Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.
A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
A purine and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway.
Tumors or cancers of the KIDNEY.
The space or compartment surrounded by the pelvic girdle (bony pelvis). It is subdivided into the greater pelvis and LESSER PELVIS. The pelvic girdle is formed by the PELVIC BONES and SACRUM.
An enzyme that oxidizes galactose in the presence of molecular oxygen to D-galacto-hexodialdose. It is a copper protein. EC
A diuretic and renal diagnostic aid related to sorbitol. It has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity.
The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Cytidine 5'-(trihydrogen diphosphate). A cytosine nucleotide containing two phosphate groups esterified to the sugar moiety. Synonyms: CRPP; cytidine pyrophosphate.
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)
A trihydroxybenzene or dihydroxy phenol that can be prepared by heating GALLIC ACID.
The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.
Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.
The relationship between the dose of an administered drug and the response of the organism to the drug.
A malignant neoplasm derived from TRANSITIONAL EPITHELIAL CELLS, occurring chiefly in the URINARY BLADDER; URETERS; or RENAL PELVIS.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
The inability in the male to have a PENILE ERECTION due to psychological or organ dysfunction.
A malignant epithelial tumor with a glandular organization.
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
An enzyme derived from cow's milk. It catalyzes the radioiodination of tyrosine and its derivatives and of peptides containing tyrosine.
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)
The theory that the radiation and absorption of energy take place in definite quantities called quanta (E) which vary in size and are defined by the equation E=hv in which h is Planck's constant and v is the frequency of the radiation.
A group of phenyl benzopyrans named for having structures like FLAVONES.
Organic compounds containing a carbonyl group in the form -CHO.
An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.
Compounds in which one or more of the ketone groups on the pyrimidine ring of barbituric acid are replaced by thione groups.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
A di-tert-butyl PHENOL with antioxidant properties.
The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.
Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)
Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)
An enzyme of the oxidoreductase class primarily found in PLANTS. It catalyzes reactions between linoleate and other fatty acids and oxygen to form hydroperoxy-fatty acid derivatives.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
The N-acetyl derivative of CYSTEINE. It is used as a mucolytic agent to reduce the viscosity of mucous secretions. It has also been shown to have antiviral effects in patients with HIV due to inhibition of viral stimulation by reactive oxygen intermediates.
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)
An agent thought to have disinfectant properties and used as an expectorant. (From Martindale, The Extra Pharmacopoeia, 30th ed, p747)
Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
A GLUTATHIONE dimer formed by a disulfide bond between the cysteine sulfhydryl side chains during the course of being oxidized.
A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.
Nitrogenous products of NITRIC OXIDE synthases, ranging from NITRIC OXIDE to NITRATES. These reactive nitrogen intermediates also include the inorganic PEROXYNITROUS ACID and the organic S-NITROSOTHIOLS.
Eighteen-carbon essential fatty acids that contain two double bonds.
Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.
Benzopyrans saturated in the 2 and 3 positions.
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).
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.
A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.
Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Transfer of a neoplasm from its primary site to lymph nodes or to distant parts of the body by way of the lymphatic system.
The outer layer of the woody parts of plants.
The treatment of a disease or condition by several different means simultaneously or sequentially. Chemoimmunotherapy, RADIOIMMUNOTHERAPY, chemoradiotherapy, cryochemotherapy, and SALVAGE THERAPY are seen most frequently, but their combinations with each other and surgery are also used.
The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.
The reversibly oxidized form of ascorbic acid. It is the lactone of 2,3-DIKETOGULONIC ACID and has antiscorbutic activity in man on oral ingestion.
A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.
Porphyrins which are combined with a metal ion. The metal is bound equally to all four nitrogen atoms of the pyrrole rings. They possess characteristic absorption spectra which can be utilized for identification or quantitative estimation of porphyrins and porphyrin-bound compounds.
Drugs used to protect against ionizing radiation. They are usually of interest for use in radiation therapy but have been considered for other, e.g. military, purposes.
A mass spectrometry technique used for analysis of nonvolatile compounds such as proteins and macromolecules. The technique involves preparing electrically charged droplets from analyte molecules dissolved in solvent. The electrically charged droplets enter a vacuum chamber where the solvent is evaporated. Evaporation of solvent reduces the droplet size, thereby increasing the coulombic repulsion within the droplet. As the charged droplets get smaller, the excess charge within them causes them to disintegrate and release analyte molecules. The volatilized analyte molecules are then analyzed by mass spectrometry.
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
Methods which attempt to express in replicable terms the level of CELL DIFFERENTIATION in neoplasms as increasing ANAPLASIA correlates with the aggressiveness of the neoplasm.
Period after successful treatment in which there is no appearance of the symptoms or effects of the disease.
Enzyme complexes that catalyze the formation of PROSTAGLANDINS from the appropriate unsaturated FATTY ACIDS, molecular OXYGEN, and a reduced acceptor.
5-Amino-2,3-dihydro-1,4-phthalazinedione. Substance that emits light on oxidation. It is used in chemical determinations.
Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.
Adverse functional, metabolic, or structural changes in ischemic tissues resulting from the restoration of blood flow to the tissue (REPERFUSION), including swelling; HEMORRHAGE; NECROSIS; and damage from FREE RADICALS. The most common instance is MYOCARDIAL REPERFUSION INJURY.
The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.
Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)
A large class of organic compounds having more than one PHENOL group.
A class of phenolic acids related to chlorogenic acid, p-coumaric acid, vanillic acid, etc., which are found in plant tissues. It is involved in plant growth regulation.
A flavonol widely distributed in plants. It is an antioxidant, like many other phenolic heterocyclic compounds. Glycosylated forms include RUTIN and quercetrin.
Graphical representation of a statistical model containing scales for calculating the prognostic weight of a value for each individual variable. Nomograms are instruments that can be used to predict outcomes using specific clinical parameters. They use ALGORITHMS that incorporate several variables to calculate the predicted probability that a patient will achieve a particular clinical endpoint.
Derivatives of the dimethylisoalloxazine (7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione) skeleton. Flavin derivatives serve an electron transfer function as ENZYME COFACTORS in FLAVOPROTEINS.
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)
The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
A flavoprotein enzyme that catalyzes the univalent reduction of OXYGEN using NADPH as an electron donor to create SUPEROXIDE ANION. The enzyme is dependent on a variety of CYTOCHROMES. Defects in the production of superoxide ions by enzymes such as NADPH oxidase result in GRANULOMATOUS DISEASE, CHRONIC.
A colorless, flammable liquid used in the manufacture of FORMALDEHYDE and ACETIC ACID, in chemical synthesis, antifreeze, and as a solvent. Ingestion of methanol is toxic and may cause blindness.
A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group.
Tumors or cancer of the UTERINE CERVIX.
Penning electrons undergo electron capture with atmospheric oxygen to produce O2−. The O2− will produce radical anions. Several ... The ions generated from atmospheric or dopant molecules undergo ion-molecule reactions with the sample molecules to produce ... Ionized water can undergo further ion-molecule reactions to form protonated water clusters ([(H 2O) nH]+ ). H 2 O + ∙ + H 2 O ... Eluate from a high-pressure liquid chromatograph (HPLC) can be also introduced to the reaction zone of the DART source and ...
... undergoes reactions characteristic of an α,β-unsaturated ketone. Hydrogenation gives the cyclohexanone derivative. ... Isophorone is degraded by attack of hydroxyl radicals. When exposed to sunlight in aqueous solutions, isophorone undergoes 2+2 ...
... undergoes the main reactions expected for a secondary alcohol. Oxidation gives cyclohexanone, which is converted ... The oxidation involves radicals and the intermediacy of the hydroperoxide C6H11O2H. Alternatively, cyclohexanol can be produced ...
This reaction produces free excited fluorine radicals. Just after the nozzle, the mixture of helium and hydrogen or deuterium ... The excited molecules then undergo stimulated emission in the optical resonator region of the laser. Deuterium fluoride lasers ... gas is injected to the exhaust stream; the hydrogen or deuterium reacts with the fluorine radicals, producing excited molecules ...
NAA present in the environment undergoes oxidation reactions with hydroxyl radicals and sulfate radicals. Radical reactions of ... Hydroxyl adduct radical was formed as the intermediate during the reaction of hydroxyl radical with NAA. The intermediate ... naphtyl methyl radical was formed during the reaction of sulfate radical anion with NAA. In micropropagation of various plants ... Radical chemistry of glucosamine naphthalene acetic acid and naphthalene acetic acid: a pulse radiolysis study. J. Phys. Org. ...
The sesquiterpene dimer undergoes a radical coupling reaction to form gossypol. The biosynthesis begins when geranyl ... and then undergoes a phenolic oxidative coupling, ortho to the phenol groups, to form gossypol (8). The coupling is catalyzed ...
... undergoes reactions expected of simple alkyl bromides. It can form Grignard reagents. It reacts with potassium ... Most 1-bromoalkanes are prepared by free-radical addition of hydrogen bromide to the 1-alkene. These conditions lead to anti- ...
Hydroxyl radicals are highly reactive and undergo chemical reactions that make them short-lived. When biological systems are ... Both the negatively charged anion OH−, called hydroxide, and the neutral radical ·OH, known as the hydroxyl radical, consist of ... According to IUPAC definitions, the term hydroxyl refers to the hydroxyl radical (·OH) only, while the functional group −OH is ... Hydroxy groups participate in the dehydration reactions that link simple biological molecules into long chains. The joining of ...
Both chloride radicals in phosgene can undergo reactions analogous to the preceding reactions of acyl halides. Phosgene is used ... In the above reactions, HX (hydrogen halide or hydrohalic acid) is also formed. For example, if the acyl halide is an acyl ... This hydrolysis is the most heavily exploited reaction for acyl halides as it occurs in the industrial synthesis of acetic acid ... On an industrial scale, the reaction of acetic anhydride with hydrogen chloride produces a mixture of acetyl chloride and ...
They undergo nucleophilic addition and substitution reactions with various electrophiles. Although nitrile anions are ... Electron transfer to a second molecule of arene carries on the radical chain. Electron-poor aromatic compounds undergo ... In these reactions, two equivalents of base are used to drive the reaction towards acylated product-the acylated product is ... and the flask was cooled in order to keep the reaction from becoming too vigorous during the initial 0.5-hour reaction period. ...
... s with electron-withdrawing groups in the ortho and para positions, can undergo SNAr reactions. For example, 2,4- ... The halides can be displaced by strong nucleophiles via reactions involving radical anions. Alternatively aryl halides, ... The similar Schiemann reaction uses the tetrafluoroborate anion as the fluoride donor. Gatterman reaction can also be used to ... To halogenate the ring, Lewis acids are required, and light should be excluded to avoid the competing reaction. The second main ...
... s undergo free-radical reactions with elemental magnesium to give alkylmagnesium compounds: Grignard reagents. ... The reactive intermediate in this reaction is a free radical and the reaction is called a radical chain reaction. Free radical ... also undergo oxidative addition reactions to give organometallic compounds. Chlorinated or fluorinated alkenes undergo ... For example, after undergoing substitution reactions, cyanoalkanes may be hydrolyzed to carboxylic acids, or reduced to primary ...
In other substitution reactions, it undergoes halogenation. Polychlorinated biphenyls were once popular pesticides. Lithium ... biphenyl contains the radical anion, which is highly reducing (-3.1 V vs Fc+/0). Several solvates of alkali metal salts of ... They are prepared by various coupling reactions including the Suzuki-Miyaura reaction and the Ullmann reaction. Polychlorinated ... This mixture is stable to 400 °C. Biphenyl does undergo sulfonation which, followed by base hydrolysis, produces p- ...
... is the decomposition of the ethoxy radical into a methyl radical and formaldehyde, which can in turn undergo further oxidation ... This reaction proceeds through the propagation of the ethyl radical: C2H5• + Cl2 → C2H5Cl + Cl• Cl• + C2H6 → C2H5• + HCl ... They mistook the product of the reactions for methyl radical rather than the dimer of methyl, ethane. This error was corrected ... An important series of reaction in ethane combustion is the combination of an ethyl radical with oxygen, and the subsequent ...
The hydroperoxides can then undergo a number of possible homolytic reactions to generate more radicals, giving an accelerating ... reaction\ to\ non-radical\ product}}} P ∙ + P ∙ ⟶ cross linking reaction to non − radical product {\displaystyle {\ce {P\bullet ... reaction to non − radical product {\displaystyle {\ce {POO\bullet +\ POO\bullet ->cross\ linking\ reaction\ to\ non-radical\ ... these reduce the number of radicals by radical disproportionation or combination, leading to a sigmoid reaction plot. Chain ...
... reaction\ to\ non-radical\ product}}} P ∙ + P ∙ ⟶ cross linking reaction to non − radical product {\displaystyle {\ce {P\bullet ... Hydroperoxides readily undergo photolysis to give an alkoxyl macroradical radical (PO•) and a hydroxyl radical (HO•), both of ... reaction to non − radical product {\displaystyle {\ce {POO\bullet +\ POO\bullet ->cross\ linking\ reaction\ to\ non-radical\ ... The alkoxyl radical may also undergo beta scission, generating a acyl-ketone and macroradical. This is considered to be the ...
Because it has no C-H bonds, carbon tetrachloride does not easily undergo free-radical reactions. It is a useful solvent for ... In organic chemistry, carbon tetrachloride serves as a source of chlorine in the Appel reaction. One specialty use of carbon ... Carbon tetrachloride was originally synthesized by the French chemist Henri Victor Regnault in 1839 by the reaction of ... but later research found that the gas actually inhibits the chemical chain reaction of the combustion process. In 1911, Pyrene ...
... of the excited melanin molecules will undergo harmful chemical reactions or produce free radicals. The cosmetic industry claims ... If the energy of the UV photon were not transformed into heat, then it would lead to the generation of free radicals or other ... When photosynthetic antenna pigments such as chlorophyll are excited by light absorption, unproductive reactions may occur by ... In fact, the substances used in sunscreens are often used as photosensitizers in chemical reactions. (see Benzophenone). ...
... radical species were detected by EPR spectroscopy. However, whether these radicals are reaction intermediates is not definitive ... The advantage of Li/Sn exchange is that the tri-alkylstannane precursors undergo few side reactions, as the resulting n-Bu3Sn ... their use is still limited due to competing side reactions such as radical reactions or metal-halogen exchange. Most ... Another possible mechanism involves single electron transfer and the generation of radicals. In reactions of secondary and ...
Both chemisorbed and physisorbed radicals can undergo the oxygen evolution competitive reaction. For this reason, the ... A reaction mechanism has been proposed for the formation of the hydroxyl radical at the anode through oxidation of water: S + H ... Due to the radicals being strongly chemisorbed onto the electrode surface, the reactions are limited to the proximity of the ... Hydroxyl radicals are physisorbed on the electrode surface by means of weak interaction forces and thus available for reaction ...
As the molecule has acrylic functionality, it is capable of undergoing the Michael reaction with an amine. This allows it use ... Like other acrylate monomers it is usually supplied with a radical inhibitor such as hydroquinone added. The material is ...
The alkyl-radical intermediate can instead undergo an intramolecular reaction with various other suitably-positioned functional ... N2 The reaction is a three-step one-pot process in which the alcohol first undergoes a Mitsunobu reaction with ortho- ... This name reaction is one of two discovered by Andrew Myers that are named after him; both this reaction and the Myers allene ... Unlike hydrazone-synthesis reactions, this reaction occurs on the same nitrogen of the hydrazine that has the arenesulfonyl ...
Étard reaction). The methyl group undergoes halogenation under free radical conditions. For example, N-bromosuccinimide (NBS) ... The reaction requires a high pressure of hydrogen and a catalyst. Toluene occurs naturally at low levels in crude oil and is a ... It undergoes sulfonation to give p-toluenesulfonic acid, and chlorination by Cl2 in the presence of FeCl3 to give ortho and ... C6H5CH3 + Br2 → C6H5CH(Br)2 + HBr C6H5CH2Br + Br2 → C6H5CHBr2 + HBr The methyl group in toluene undergoes deprotonation only ...
Under free-radical conditions the P-H bonds of primary and secondary phosphines add across alkenes. Such reactions proceed with ... Phosphorus halides undergo Nucleophilic displacement by organometallic reagents such as Grignard reagents. Conversely, some ... The main reaction types of phosphines are as nucleophiles and bases. Their nucleophilicity is evidence by their reactions with ... Phosphites are employed in the Perkow reaction and the Michaelis-Arbuzov reaction. They also serve as ligands in organometallic ...
... undergoes photodissociation, eventually forming O2 and Cl2. The process is primarily radical based, with ... It has been suggested that dichlorine monoxide may be the active species in the reactions of HOCl with olefins and aromatic ... 2 Cl2 + HgO → HgCl2 + Cl2O A safer and more convenient method of production is the reaction of chlorine gas with hydrated ... Basco, N.; Dogra, S. K. (22 June 1971). "Reactions of Halogen Oxides Studied by Flash Photolysis. II. The Flash Photolysis of ...
The driving force for the reaction is the formation of highly stable molecular nitrogen. There is a radical variant of this α,β ... The proton transfer leads to intermediate (4), which undergoes the key fragmentation to alkyne (6) and the corresponding ... Grob fragmentation Wharton reaction Shapiro reaction Ohloff, G.; Becker, J.; Schulte-Elte, K. H. (1967). "Synthese von Exalton ... The reaction is also sometimes known as the Eschenmoser-Ohloff fragmentation or the Eschenmoser-Tanabe fragmentation as Masato ...
This may undergo a fragmentation reaction in either direction to yield either the starting species or a radical (R•) and a ... Ideally, the RAFT adduct radical is sufficiently hindered such that it does not undergo termination reactions. The position of ... RAFT agents with a radical stabilising Z-group such as Phenyl group favor the adduct radical, as do propagating radicals whose ... The reaction is started by a free-radical source which may be a decomposing radical initiator such as AIBN. In the example in ...
Sometimes these radicals initiate chain reactions. Ascorbate can terminate these chain radical reactions by electron transfer. ... The net reaction is: RO• + C 6H 7O− 6 → RO− + C6H7O• 6 → ROH + C6H6O6 On exposure to oxygen, ascorbic acid will undergo further ... excess ascorbate in the presence of free metal ions can not only promote but also initiate free radical reactions, thus making ... It is oxidized with loss of one electron to form a radical cation and then with loss of a second electron to form ...
... is often a complicated sequence of elementary radical reactions. Solid fuels, such as wood and coal, first undergo ... Solid and heavy liquid fuels also undergo a great number of pyrolysis reactions that give more easily oxidized, gaseous fuels. ... Combustion in oxygen is a chain reaction in which many distinct radical intermediates participate. The high energy required for ... These reactions are endothermic and require constant energy input from the ongoing combustion reactions. A lack of oxygen or ...
Many acids undergo oxidative decarboxylation. Enzymes that catalyze these reactions are known as carboxylases (EC 6.4.1) and ... Carboxyl radicalEdit. The radical •COOH (CAS# 2564-86-5) has only a fleeting isolated existence.[8] The acid dissociation ... Less-common reactionsEdit. Many reactions afford carboxylic acids but are used only in specific cases or are mainly of academic ... Halogenation followed by hydrolysis of methyl ketones in the haloform reaction. *The Kolbe-Schmitt reaction provides a route to ...
This produced a reaction which led to all the colonies restricting Chinese and other Asian immigration. This was the foundation ... Labour unions emerged in Japan in the second half of the Meiji period as the country underwent a period of rapid ... More permanent trade unions were established from the 1850s, better resourced but often less radical. The London Trades Council ... and radical unionists.[41] In the immediate aftermath of the Second World War, the US Occupation authorities initially ...
... acnes by oxidizing its proteins through the formation of oxygen free radicals and benzoic acid. These free radicals likely ... The approach to acne treatment underwent significant changes during the twentieth century. Retinoids became a medical treatment ... If the inflammatory reaction is severe, the follicle can break into the deeper layers of the dermis and subcutaneous tissue and ... the scale has undergone several revisions.[69] The Leeds acne grading technique counts acne lesions on the face, back, and ...
A precise reaction mechanism has never been proposed, although it is likely similar to the Pinner reaction; preceding via an ... The ring is thermally stable[25] and resistant to nucleophiles, bases, radicals, and weak acids[26] as well as being fairly ... 2-Oxazolines, such as 2-ethyl-2-oxazoline, can undergo living cationic ring-opening polymerisation to form poly(2-oxazoline)s.[ ... Their preparation, reactions, and applications". Chemical Reviews. 71 (5): 483-505. doi:10.1021/cr60273a003.. ...
The reaction is either nothing, or WP:Thanks notices. Just recently: [1]. I don't think anyone bothers with this gnoming except ... It's not exactly a radical new idea; it's the first line of Struck & White The Elements of Style 4th ed. (2000): "1. Form the ... including when it underwent GA review and FA candidacy; and MOS:POSS states:. For the possessive of singular nouns ending with ... and see what the reaction is? EEng 07:02, 2 December 2017 (UTC) I'm entirely calm. (But "Sandy?") I don't have patience for ...
In radical contrast to the Promethean illusion, God reveals himself in history, especially personified in Jesus Christ, as ... Anti-Catholicism surged in Detroit in the 1920s in reaction to the rise in the number of Catholic immigrants from southern ... I underwent a fairly complete conversion of thought which involved rejection of almost all the liberal theological ideals and ...
Reaction with water On reaction with water, they generate hydroxide ions and hydrogen gas. This reaction is vigorous and highly ... Caesium-137 undergoes high-energy beta decay and eventually becomes stable barium-137. It is a strong emitter of gamma ... polarisable radical anions, such as the dark-green sodium naphthalenide, Na+[C10H8•]−, a strong reducing agent.[123]:266 ... Representative reactions of alkali metalsEdit. Reaction with oxygen Upon reacting with oxygen, alkali metals form oxides, ...
... substructure that stops oxidation by acting as a scavenger of free radicals that are responsible for oxidative chain reactions. ... In rats, quercetin did not undergo any significant phase I metabolism.[19] In contrast, quercetin did undergo extensive phase ... Williams RJ, Spencer JP, Rice-Evans C (Apr 2004). "Flavonoids: antioxidants or signalling molecules?". (review). Free Radical ... The exception is the 5-hydroxyl group of the flavonoid ring which generally does not undergo glucuronidation. The major ...
... who underwent independent developments for more than a century and have developed an ethnic identity in their own right.[53] ... primarily to the radical secularization, the centralization of authority, and to the rampant Turkish nationalism in the new ... movement that emerged following World War I and the end of the Ottoman Empire in 1922 largely represented a reaction to the ...
Radical materials advances can drive the creation of new products or even new industries, but stable industries also employ ... Diffusion is important in the study of kinetics as this is the most common mechanism by which materials undergo change. ... It forms the foundation to treat general phenomena in materials science and engineering, including chemical reactions, ...
He underwent surgery at St Thomas' Hospital and was taken off the critical list on 4 June.[28] A British Transport Police ... a b UK's Rudd says London attackers probably "radical Islamist terrorists", Reuters, 4 June ... Reactions[edit]. Floral tributes left on London Bridge following the attack. The Prime Minister, Theresa May, returned to ... On 4 June the Home Secretary, Amber Rudd, said that "We are confident about the fact that they were radical Islamic terrorists ...
Reactions by other citiesEdit. As the death toll in the city rose, officials in neighboring communities and major port cities ... The mortality rate that year was roughly the same as it had been at Bush Hill in 1793, despite radical difference between the ... Natives thought that newcomers especially had to undergo a "seasoning" and were more likely to die of what were thought to be ... Richard Allen and Absalom Jones recalled their reaction to the letter in a memoir they published shortly after the epidemic: ...
The reactions are summarized below: Si + 2 H2 + 3 SiCl4 → 4 SiHCl3. 2 SiHCl3 → SiH2Cl2 + SiCl4. 2 SiH2Cl2 → SiHCl3 + SiH3Cl. 2 ... A second consequence is that silane is pyrophoric - it undergoes spontaneous combustion in air, without the need for external ... This redistribution reaction requires a catalyst: 4 HSiCl3 → SiH4 + 3 SiCl4. The most commonly used catalysts for this process ... It may also be thought of as a disproportionation reaction even though there is no change in the oxidation number for silicon ( ...
... its potential to undergo a certain set of chemical reactions with other substances. However, this definition only works well ... Some molecules contain one or more unpaired electrons, creating radicals. Most radicals are comparatively reactive, but some, ... A reaction is said to be exothermic if the reaction releases heat to the surroundings; in the case of endothermic reactions, ... Many reaction intermediates with variable stability can thus be envisaged during the course of a reaction. Reaction mechanisms ...
Reaction products of primary cosmic rays, radioisotope half-lifetime, and production reaction.[82]. *Tritium (12.3 years): 14N( ... At distances of ≈94 AU from the Sun, the solar wind undergoes a transition, called the termination shock, from supersonic to ... Cosmic rays ionize the nitrogen and oxygen molecules in the atmosphere, which leads to a number of chemical reactions. Cosmic ... Currently the Pierre Auger Observatory undergoes an upgrade to improve its accuracy and find evidence for the yet unconfirmed ...
... serious allergic reactions that can cause death).[4] When activated, mast cells rapidly release characteristic granules, rich ... these cells undergo activation (one of their PRRs recognizes a PAMP) and release inflammatory mediators responsible for the ... free oxygen radicals and hypochlorite. Neutrophils are the most abundant type of phagocyte, normally representing 50-60% of the ... in which cells at the site of infection undergo rapid programmed cell death to prevent the spread of the disease to other parts ...
Chemical reactionsEdit. In a gasifier, the carbonaceous material undergoes several different processes: Pyrolysis of ... and free radical.[1][7][8][9] ... via the reactions C. +. H. 2. O. →. H. 2. +. C. O. {\ ... Letting C represent a carbon-containing organic compound, the basic reaction here is C. +. O. 2. →. C. O. 2. {\displaystyle {\ ... Catalysts are used in more sophisticated reactors to improve reaction rates, thus moving the system closer to the reaction ...
A radical group continued to fight the government, but signed its own peace treaty in 2001. The war ended in a government ... About 93.1% of Djibouti's women and girls have undergone female genital mutilation (female circumcision),[97] a pre-marital ... converts may encounter negative reactions from their family and clan or from society at large, and they often face pressure to ... About 94% of Djibouti's male population have also reportedly undergone male circumcision.[102] ...
Indirect ionization happens as a result of the ionization of water, forming free radicals, notably hydroxyl radicals, which ... The reaction may become more severe during the treatment and for up to about one week following the end of radiation therapy, ... Targeting double-stranded breaks increases the probability that cells will undergo cell death. Cancer cells are generally less ... Skin reactions tend to be worse in areas where there are natural folds in the skin, such as underneath the female breast, ...
Reorganization and undergoing projects[edit]. The University of Turin is engaged not only in redesigning its teaching structure ... Pietro Biginelli, chemist, discovered the Biginelli reaction. *Renato Dulbecco, virologist and winner of the 1975 Nobel Prize ... the first year of the reform of university studies passed by Victor Amadeus II in the context of a radical renewal at all ...
"Living to 120 and Beyond: Americans' Views on Aging, Medical Advances and Radical Life Extension , Pew Research Center". ... finds a correlation between advancing age and slowness of reaction and physical and mental task performance.[44] However, ... most 85+ people will undergo extended "frailty and disability".[89] ...
Colin Tipping, Radical Forgiveness: Making Room for the Miracle, 1997, ISBN 0-9704814-1-1 ... As they thought to answer, she observed their reaction. She observed their blood pressure, heart rate, facial muscle tension, ... undergoes a change in feelings and attitude regarding a given offense, and overcomes [1][2][3] negative emotions such as ... "Charles E. Moore, Radical, Communal, Bearing Witness: The Church as God's Mission in Bruderhof Perspective and Practice". ...
Sinoff, C. L (1991). "Radical irradiation for carcinoma of the prostate". South African Medical Journal = Suid-Afrikaanse ... Matter can be accelerated beyond this speed (although still to less than c) during nuclear reactions and in particle ... Cherenkov light emission imaged from the chest wall of a patient undergoing whole breast irradiation, using 6 MeV beam from a ... The glow continues after the chain reaction stops, dimming as the shorter-lived products decay. Similarly, Cherenkov radiation ...
Due to this policy, Islam, as with all other faiths in the country, underwent radical changes. Decades of state atheism, which ... In its essence Albanian nationalism was a reaction to the gradual disintegration of the Ottoman Empire and a response to the ... Takeyh, Ray; Gvosdev, Nikolas K. (2004). The receding shadow of the prophet: The rise and fall of radical political Islam. ... Albanian nationalism overall was a reaction to the gradual breakup of the Ottoman Empire and a response to Balkan and Christian ...
The majority of his allegedly radical work consisted of hosting fundraisers for the Republican cause in the Spanish Civil War ... After inconclusive surgery, he underwent unsuccessful radiation treatment and chemotherapy late in 1966.[229] He fell into a ... Brigadier General Thomas Farrell, who was present in the control bunker at the site with Oppenheimer, summarized his reaction ... In August of that year, he met Katherine ("Kitty") Puening, a radical Berkeley student and former Communist Party member. Kitty ...
Free radical reactions are redox reactions that occur as a part of homeostasis and killing microorganisms, where an electron ... The oxygen atoms undergo reduction, formally gaining electrons, while the carbon atoms undergo oxidation, losing electrons. ... Redox reactions at Chemguide. *Online redox reaction equation balancer, balances equations of any half-cell and full reactions ... because two half-reactions always occur together to form a whole reaction. When writing half-reactions, the gained or lost ...
Sodium and fluorine undergoing a redox reaction to form sodium fluoride. Sodium loses its outer electron to give it a stable ... such as radicals, molecular ions, Rydberg molecules, transition states, van der Waals complexes, or systems of colliding atoms ...
In 1999, the radical anarchist Ricardo Flores Magón was honored with the Metro Ricardo Flores Magón station. Also opening in ... "The Church represented a force for reaction, especially in the countryside."[71] However, when Huerta cracked down on political ... until Mexico underwent an economic liberal reform process that started in the 1980s.[19] ... The popular heroes of the Mexican Revolution are the two radicals who lost: Emiliano Zapata and Pancho Villa.[19] Dynamic ...
... as well as the changes it undergoes during chemical reactions. Below is a list of chemistry-related articles. Chemical ... radical (chemistry) radioisotope Radium Radon Radon fluoride Raman spectroscopy Raoult's law Redox Reduction Reflux Reversible ... reaction Rhazes Rhenium Rhodium Rhyolite Rhyolitic Richard Adolf Zsigmondy Richard Kuhn Richard Laurence Millington Synge ... Hassel Oganesson ohm Olivine Opal Optical isomerism Organic chemistry organic compound Organic nomenclature Organic reaction ...
The resulting reaction in the plasma is the formation of carbonic acid which is in equilibrium with the plasma partial pressure ... these cells respond to the sodium concentration in the renal tubular fluid after it has already undergone a certain amount of ... which will sometimes ignore a radical new discovery for years because it destabilizes previously accepted norms. ... Such anticipatory reactions are open loop systems which are based, essentially, on "guess work", and are not self-correcting.[ ...
... the intensity may decrease because of the disappearance of peroxy radicals required for the above glow reactions.[8] ... This rare and transparent flame is a sign of a profound metamorphosis that the ether undergoes ; it is characterized by the ... It is usually produced in a chemical reaction of a certain fuel-air mixture. Contrary to conventional flame, the reaction is ... The latter mainly aim at removing the radicals (such as CH2O* mentioned above) thereby suppressing the major source of the cool ...
... and the reactive hydroxyl radical (OH.). H2O2 although not itself a free radical, forms reactive compounds in reactions that ... catalase is synthesized on free ribosomes, and they are packaged into peroxisomes without undergoing a proteolytic processing. ... H2O2 and free radicals are produced as a result of certain oxidative reactions involved in the break down of amino acids and ... H2O2 also reacts with the superoxide radical to produce even more reactive free radicals. H2O2, as well as superoxide anion (O2 ...
Allergic reaction to intravenous CT contrast (if premedicated, pt will not be excluded) ... Radiation: High-Dose Single-Fraction Image-Guided Radiotherapy for Men Undergoing Radical Prostatectomy Phase 1 ... Radiation: High-Dose Single-Fraction Image-Guided Radiotherapy for Men Undergoing Radical Prostatectomy A baseline DCE-MRI will ... Feasibility and Safety Study Using Preoperative High-Dose Single-Fraction Image-Guided Radiotherapy for Men Undergoing Radical ...
On , Feruary 5th,1996, she underwent radical gastrectomy. During the operation , the tumour was located near the pylorus which ... reaction). , The patient is emaciated,asthenia, so mo chemotherapy was performed. , On April 1st,1996, she took cephalexia ... underwent radical gastrectomy and gastroduodenostomy. , Pthology report:adenocarcinoma,infiltrating type, pylorus lymph , ...
... reaction of radicals formed in the neighborhood of DNA with DNA, e.g.,... ... As thiyl radicals are known to also undergo the reverse reaction, i.e., H-abstraction from suitable solutes, some experiments ... The products of reactions are compared with those formed by OH radical attack. The reaction of e aq − with the nucleobases ... Reactions of OH Radicals with Poly(U) in Deoxygenated Solutions: Sites of OH Radical Attack and the Kinetics of Base Release. ...
Jones underwent lengthening of the tibia, the lower leg bone, last August and will have surgery on her upper arms early next ... For dwarfs, mixed reaction to radical limb lengthening procedure *PAUL PAYNE Associated Press Writer ... It s been more than six months since the 19-year-old woman underwent leg surgery and she s eager to get the casts off and ... has defended herself from critics who say she was forced to undergo limb lengthening by tall parents and that she s turned her ...
By showing that atmospheric air quality determines the concentration of radicals in lichens, we prove that electron ... Russian researchers have shown free radical concentrations in lichens to be directly related to air pollution. ... they readily undergo chemical reactions with other molecules. As a result of an elevated concentration of such reactive species ... Metal ions and free radicals of organic molecules are involved in enzymatic reactions vital to our health. But when ions and ...
A recent theoretical investigation has been able to elucidate the reaction cascade as shown below.[8] Luminol is first ... After cyclization to the endoperoxide, the mono-anion will undergo decomposition without luminescence, if the pH is too low (, ... deprotonated in basic conditions, then oxidized to the anionic radical. Which in turn has two paths available to give the key ... The amount of catalyst necessary to cause the reaction is very small relative to the amount of luminol, allowing detection of ...
In case of thermal or chemical initiation of the free radical chain reaction, the N-halogenated ammonium salt 22 undergoes ... Free radical reaction Barton reaction Majetich, G.; Wheless, K. (1995). "Remote intramolecular free radical functionalizations ... Based on this evidence, they correctly proposed that the reaction proceeds via a radical chain reaction pathway. More ... The Hofmann-Löffler reaction (also referred to as Hofmann-Löffler-Freytag reaction, Löffler-Freytag reaction, Löffler-Hofmann ...
This oxygen-based chemical reaction releases chemical radicals into the air. If there is sunlight present, the radicals cause ... The process begins when volatile organic compounds (VOCs) undergo oxidation. ... As a result, radicals that were normally neutralized by fine particulate matter were now free to react with NOx and VOCs. This ... A number of chemical reactions is responsible for the formation of ozone. ...
N.B: high temperature generates more radicals leading to:. - an increase in reaction kinetics (runaway risk),. - shorter ... Reaction. Chemistry. Thermal initiation (GPPS). Styrene can undergo self initiated "thermal" polymerization. Process parameter ... Reaction Section. Run away Reaction. The polymerization reaction control is based on the following parameters:. Temperature. ... Run away reaction can occur in reactors. - Loss of cooling power.. - Loss of agitation in reactor.. Run away reaction can occur ...
OH radicals, using standard systems of assays. The total antioxidant capacity, total phenolic and total flavonoid content of ... methanol extracts of Hypericum mysorense prepared from various parts of the plant were tested in vitro for their free radical ... Though by itself a weak oxidant, it can undergo a Fenton-type reaction to form potent •OH radical; hence, it was of interest to ... OH radicals through the Fenton reaction by forming chelates with metals, like iron and copper [9]. ...
... and non-radicals like H2O2 and 1O2. The ROS production in plants is mainly localized in the chloroplast, mitochondria and ... and non-radicals like H2O2 and 1O2. The ROS production in plants is mainly localized in the chloroplast, mitochondria and ... The major members of the ROS family include free radicals like O•−2, OH• ... The major members of the ROS family include free radicals like O2● −, OH● ...
... undergo addition reactions. In this experiment molecules of phenylethene (styrene) - the monomer - add on to each other to form ... Alkenes (carbon compounds containing double bonds) undergo addition reactions. In this experiment molecules of phenylethene ( ... resulting in the formation of two free radicals, CH3(CH2)10COO.. It is these free radicals that attack and open the double bond ... Alkenes (carbon compounds containing double bonds) undergo addition reactions. In this experiment molecules of phenylethene ( ...
These radicals undergo dismutation to hydrogen peroxide. Thereafter highly reactive hydroxyl radicals are formed by the Fenton ... reaction. The action of reactive oxygen species with a simultaneous massive increase in cytosolic calcium concentration causes ... As a result of the streptozotocin action, B cells undergo the destruction by necrosis. This article was published in Physiol ... Alloxan and the product of its reduction, dialuric acid, establish a redox cycle with the formation of superoxide radicals. ...
These radicals undergo dismutation to hydrogen peroxide. Thereafter highly reactive hydroxyl radicals are formed by the Fenton ... reaction. The action of reactive oxygen species with a simultaneous massive increase in cytosolic calcium concentration causes ... formation of superoxide radicals. Consequently, hydrogen peroxide and hydroxyl radicals are also generated. Furthermore, ... Alloxan and the product of its reduction, dialuric acid, establish a redox cycle with the formation of superoxide radicals. ...
VDF undergoes reactions with hydroxyl radicals in the atmosphere. Using a degradation rate constant of 2.27E-12 cm3/molecule/ ... ses the half life of VDF AOPWIN™ vv1.92a (U.S. EPA, 2008), based on a 12-hr day with an OH radical concentration of 1.5E6 OH/ ...
Penning electrons undergo electron capture with atmospheric oxygen to produce O2−. The O2− will produce radical anions. Several ... The ions generated from atmospheric or dopant molecules undergo ion-molecule reactions with the sample molecules to produce ... Ionized water can undergo further ion-molecule reactions to form protonated water clusters ([(H 2O) nH]+ ). H 2 O + ∙ + H 2 O ... Eluate from a high-pressure liquid chromatograph (HPLC) can be also introduced to the reaction zone of the DART source and ...
Adduct radicals or carbocations may undergo ligand-transfer reactions, yielding γ-functionalized carbonyl compounds. When ... Manganese-mediated coupling reactions are radical coupling reactions between enolizable carbonyl compounds and unsaturated ... mediated radical reactions begins with the single-electron oxidation of a carbonyl compound to an α-oxoalkyl radical. Addition ... dioxoalkyl radicals. Radicals generated in this manner may then undergo inter- or intramolecular addition to carbon-carbon ...
... and a radical cure-inducing composition. Reaction products of the compositions of this invention exhibit superior resistance of ... The present invention is directed to radical-curable adhesive compositions which include a (meth)acrylate component; a thermal ... To reach the cured state, the compounds undergo a 2-stage curing process involving an initial acid catalyzed addition ... such as free-radical initiators, free-radical accelerators, inhibitors of free-radical generation, as well as metal catalysts. ...
Free radicals and/or ROS and RNS can be produced during both the formation of MG and its degradation; the reactions involved in ... These adducts can undergo other reactions; they can add a second MG molecule yielding either N. -(4-carboxy-4,6-dimethyl-5,6- ... is considered a source of carbon-centered radicals and superoxide [87, 88]; similarly, the nonenzymatic reaction from ... Glycation of proteins is a complex series of parallel and sequential reactions known as Maillard reaction [58]. Glycation ...
Radicals can be formed in various way, and they have various fates. Radicals are prone to undergo chain substitution and/or ... Read more about radical chemistry here.. Diradical Reaction Chemistry. Diradicals may appear to be rather obscure species, ... Five Reaction Chemistry Paradigms. Each of the five reaction chemistries can be considered to be a paradigm, where a paradigm ... Photochemical and redox methods can be used to produce radicals. There are many examples like this in reaction chemistry space ...
Mitochondrial Hypothesis of Aging Is Undergoing Revision. Oxidative Stress Defined as a Deadly Free Radical-Mediated Chain ... Reaction: Case History of Paraquat. Membranes of Deep-Sea Bacteria as Surrogates for Mitochondrial Membranes of Humans ...
As used here and hereafter, the term "inert liquid" refers to a liquid that does not undergo a polymerization reaction when ... Upon irradiation, Type I initiators undergo fragmentation to yield initiating radicals. The majority of Type I initiators are ... Type II initiators mainly undergo two reaction pathways, hydrogen abstraction by the excited initiator, and photoinduced ... The reaction schemes illustrate that the pH-sensitive polymer gels prepared at a predetermined location in a microscale channel ...
... radical anions, which can further undergo a series of reactions to generate an HO• radicals which can then oxidize the adsorbed ... In this process, O3 is decomposed into free radicals follow by instantaneous reaction of the free radicals with the pollutants. ... radical may not take part in further oxidation process and gets protonated to generate a hydroperoxyl radicals (HO2•) and ... Instantaneously, electrons in the CB (eCB−) also react with the adsorbed oxygen molecule to produce O2−• radical as shown in Eq ...
Hydroxyl radicalEdit. Main article: Hydroxyl radical. Hydroxyl radicals are highly reactive and undergo chemical reactions that ... Both the negatively charged anion OH−, called hydroxide, and the neutral radical ·OH, known as the hydroxyl radical, consist of ... According to IUPAC rules, the term hydroxyl refers to the hydroxyl radical (·OH) only, while the functional group −OH is called ... When biological systems are exposed to hydroxyl radicals, they can cause damage to cells, including those in humans, where they ...
1,2-Dichloropropane undergoes reactions with hydroxyl radicals in the atmosphere. The half-life of 1,2-dichloropropane due to ... 2-dichloropropane for the reaction with OH radicals is 34.9 days, based on an OH radical concentration of 5 x 10e5 molecules/ ... The reaction of 1,2-dichloropropane with hydroxyl radicals has been measured experimentally in several studies. The measured ... These chlorinated carbonyl compounds may be lost by further reaction with OH radicals, by photolysis, or by wet deposition. ...
Table 3. Adverse reactions of patients in the two groups (n (%)).. Discussion. In patients undergoing radical surgery of ... Seventy-six patients undergoing radical resection of esophageal cancer under general anesthesia in our hospital were selected ... Patients undergoing radical resection of esophageal cancer under general anesthesia are characterized by poor body resistance, ... Adverse reactions of patients in the two groups. The incidence of adverse reactions in the patients in the observation group ...
D. X. Tan, L. D. Chen, and B. Poeggeler, "Melatonin: a potent endogenous hydroxyl radical scavenger," Endocrine Journal, vol. 1 ... A. Schroeder, E. Van Der Zypen, H. Stich, and F. Sutter, "The reactions of bone, connective tissue, and epithelium to endosteal ... Throughout life, bone tissue undergoes a continuous process of resorption and formation. By continuing, there are areas of bone ... Melatonin promotes bone formation [39] and on the other hand with its antioxidant action on free radicals interferes with the ...
  • Thereafter highly reactive hydroxyl radicals are formed by the Fenton reaction. (omicsonline.org)
  • Hydroxyl radicals are highly reactive and undergo chemical reactions that make them short-lived. (wikipedia.org)
  • Free radicals, more accurately described as atoms or molecules with unpaired electrons, are highly reactive and readily undergo chemical reactions (1). (nutrametrix.com)
  • When the concentration of free radicals exceeds the neutralizing capability of the body's antioxidants, these highly reactive species can damage vital molecules such as DNA, RNA, enzymes and structural proteins and large amounts of membrane lipids though peroxidation. (nutrametrix.com)
  • Researchers at the CNS Institute will study how environmental toxins that produce free radicals (highly reactive molecules related to oxygen and nitrogen) can enhance or mimic genetic mutations that contribute to Parkinson's disease. (bio-medicine.org)
  • Although oxygen is a relatively stable free radical, many radicals are highly reactive. (universalclass.com)
  • Free radicals are molecules that, because they contain an unpaired electron, are extremely reactive. (madsci.org)
  • Metal ions and free radicals of organic molecules are involved in enzymatic reactions vital to our health. (eurekalert.org)
  • Radicals are somewhat similar: This term is reserved for all other ions, atoms, and even whole molecules of organic or inorganic compounds that have an unpaired electron. (eurekalert.org)
  • that is, they readily undergo chemical reactions with other molecules. (eurekalert.org)
  • The ions generated from atmospheric or dopant molecules undergo ion-molecule reactions with the sample molecules to produce analyte ions. (wikipedia.org)
  • Nonenzymatic protein glycation is an endogenous process in which reducing sugars react with amino groups in proteins through a series of Maillard reactions forming reversible Schiff base and Amadori compounds, producing a heterogeneous class of molecules, collectively termed advanced glycation end products (AGEs) [ 9 ]. (hindawi.com)
  • Hydroxy groups participate in the dehydration reactions that link simple biological molecules into long chains. (wikipedia.org)
  • The half-life of 1,2-dichloropropane due to this reaction is 34.9 days at 25 C with an OH radical concentration of 5 x 10e5 molecules/cm3 and 24 hour photoday. (europa.eu)
  • The calculated atmospheric half-life of 1,2-dichloropropane for the reaction with OH radicals is 34.9 days, based on an OH radical concentration of 5 x 10e5 molecules/cm3 and 24 hour photoday. (europa.eu)
  • Generally, many reactions of cd-substituted molecules appear to involve radicals. (docme.ru)
  • Some small molecules in the atmosphere can also act as photoinitiators by decomposing to give free radicals, as is in the case of photochemical smog. (openpr.com)
  • It has been shown to protect critical molecules in the body such as lipids, proteins, and nucleic acids from free radicals and reactive oxygen species (1). (nutrametrix.com)
  • Becker et al (1974) determined the rate constant for reaction of VDF with ozone to be 8E-20 cm3/molecules at ambient temperature. (europa.eu)
  • Assuming the mean tropospheric O3 concentration to be 7.5E11 molecules/cm3, the half-life of VDF with respect to reaction with O3 is 134 days. (europa.eu)
  • Combining those reaction patterns could realize a new reaction methodology to synthesize complex molecules including C-C multiple bonds. (beilstein-journals.org)
  • Our observations suggest that alkane cations rapidly undergo proton transfer to neutral alkane molecules, in competition with geminate recombination. (springer.com)
  • A biochemical method of assaying for ligand molecules in fluids based on the specific interaction of a ligand and a ligand-recognition molecule that binds the ligand wherein a free radical forming group is covalently coupled to label either a ligand sought to be assayed or the ligand recognition molecule. (google.co.uk)
  • A biochemical method of assaying for ligand molecules in fluids based on the specific interaction of a ligand and a ligand-recognition molecule that binds the ligand wherein a free radical forming group is covalently coupled to label either a ligand sought to be assayed or the ligand recognition molecule or is internally generated from the ligand or ligand recognition molecule, and directly or indirectly assaying for the ligand. (google.co.uk)
  • 8. A method as described in claim 7 wherein said covalent bonding is the product of reacting a free radical forming group with hydroxyl groups of said ligands or said ligand recognition molecules. (google.co.uk)
  • 9. A method according to claim 4 wherein contacting said separated complex with a solution containing said component comprises a component that exhibits detectable surface active properties upon reaction with free radical molecules. (google.co.uk)
  • the triplet ground state diatomic O 2 molecule is paramagnetic and exists in air as a free radical, constrained from reacting aggressively with the brain's organic molecules due to its "spin restriction", a thermodynamic quirk of evolutionary fate. (springer.com)
  • The present research was designed to examine the influence of phenolic compounds on the efficiency of activated carbon in removing chlorite and to study the reactions between chlorite, activated carbon and organic molecules. (erudit.org)
  • Why do aromatic hydrocarbon molecules primarily react via electrophilic substitution reaction? (docbrown.info)
  • the dot identifies the unpaired electron) and the reactive hydroxyl radical (OH. (madsci.org)
  • Hydroxyl Radical-Induced Oxidation of D-Glucose in Oxygenated Aqueous Solution. (springer.com)
  • For the Hydroxyl radical, see Hydroxyl radical . (wikipedia.org)
  • Both the negatively charged anion OH − , called hydroxide , and the neutral radical ·OH, known as the hydroxyl radical , consist of an unbounded hydroxyl group. (wikipedia.org)
  • According to IUPAC rules, the term hydroxyl refers to the hydroxyl radical (·OH) only, while the functional group −OH is called hydroxy group. (wikipedia.org)
  • Reducing power and hydroxyl radical scavenging activity assays were used to measure antioxidant activity. (biomedcentral.com)
  • Total phenolic content showed positive correlations with reducing power and lipid peroxidation inhibition (LPOI) % in floral extracts as well as with hydroxyl radical scavenging activity and LPOI % in root extracts. (biomedcentral.com)
  • Protonation forms peroxynitrous acid, which can undergo homolytic cleavage to form hydroxyl radical and nitrogen dioxide. (bionity.com)
  • produce a methyl radical (CH3) and a hydroxyl radical (OH). (scribd.com)
  • The Hydroxyl radical is especially important in the formation of smog and in a wide variety of other kinds of photo chemical reactions. (scribd.com)
  • More specifically, Wawzonek and Thelan suggested that the N-chloroamine is first protonated with the acid and then undergoes homolytic cleavage under the influence of heat, light, or other initiators to afford amminium and chloride free radicals. (wikipedia.org)
  • As an example of dissociation, hydrogen peroxide can undergo homolytic cleavage, with the O-O bond cleaving to form two hydroxyl radicals. (openpr.com)
  • Assume the molecule 2-methylbutane undergoes homolytic cleavage to produce two free radicals: a hydrogen atom and an alkyl radical. (universalclass.com)
  • This carbon is the most likely candidate for homolytic cleavage because the radical form of the molecule is most stable when the unpaired electron is located there. (universalclass.com)
  • This reaction is called a chain reaction because, as we will see, homolytic cleavage of chlorine (the so-called initiation step of the reaction) yields free radicals that can yield a disproportionate amount of the reaction's products. (universalclass.com)
  • Sample analysis revealed their iron, copper, and manganese content, along with free radical concentrations of phenol and polyphenol -- two types of compounds occurring naturally in lichens. (eurekalert.org)
  • The process begins when volatile organic compounds (VOCs) undergo oxidation. (naturalnews.com)
  • When released to the air, both compounds have the potential to undergo photolysis. (cdc.gov)
  • Alkenes (carbon compounds containing double bonds) undergo addition reactions. (rsc.org)
  • Manganese-mediated coupling reactions are radical coupling reactions between enolizable carbonyl compounds and unsaturated compounds initiated by a manganese(III) salt, typically manganese(III) acetate. (wikipedia.org)
  • Manganese(III) acetate is a one-electron oxidizing agent that is particularly effective for the oxidation of enolizable carbonyl compounds to α-oxoalkyl or α,α'-dioxoalkyl radicals. (wikipedia.org)
  • Adduct radicals or carbocations may undergo ligand-transfer reactions, yielding γ-functionalized carbonyl compounds. (wikipedia.org)
  • 4) Aromatic compounds are also useful radical acceptors in manganese(III)-mediated coupling reactions. (wikipedia.org)
  • 7) When alkenes or carbonyl compounds containing pendant unsaturated moiety are treated with manganese(III) acetate, tandem intramolecular cyclization reactions may occur. (wikipedia.org)
  • These chlorinated carbonyl compounds may be lost by further reaction with OH radicals, by photolysis, or by wet deposition. (europa.eu)
  • Capto-dative Substituent Effects in Syntheses with Radicals and RadicophilesI**] methods (32) By Heinz Gunter Viehe, Robert Merenyi, Lucien Stella, and Zdenek Janousek''] Dedicated to the double anniversary: 100 years Wurster's salts and SO years Paneth's radical reactions with metal mirrors The 100 years old Wurster's salts have long been recognized as compounds with radical cations. (docme.ru)
  • 1. Introduction In 1879, Wurster's salts (1) were discovered[']but their radical nature was recognized only about half a century later[*I. tramethyllead when exposed to a stream of methyl radicals generated by thermolysis from other organometallic compounds such as trimethylbismuth (Fig. 1). (docme.ru)
  • A preopolymr of the invention is prepared in a one-pot procedure according to the Micahel addition of thiol to electron deficient alkenes, such as α,β-unsaturated carbonyl compounds, without need for additional reaction step(s) to introduce actinically crosslinkable groups. (google.com)
  • Certain azo compounds such as azobisisobutyronitrile can also photolytically cleave, forming two alkyl radicals and nitrogen gas. (openpr.com)
  • Polyphenols have carbon-based aromatic phenyl-ring compounds which are easily oxidized to quinones by ROS, a property that helps account for their free radical scavenging capacity. (biomedcentral.com)
  • Compounds 3-(4-chlorophenyl)-1-(4-piperidin-1-yl-phenyl)prop-2-en-1-one (3), 1-(4-ben-zotriazol-1-yl-phenyl)-3-(4-methoxyphenyl)prop-2-en-1-one (5), and 3-(4-methoxyphenyl)-1-(4-pyrrolidin-1-yl-phenyl) prop-2-en-1-one (7) exhibited major irreversible effects on viability and resulted in parasite death and also inhibited the GST activity by 84-100 % in vitro. (psu.edu)
  • Recently, we have prepared quaternary carbon centers via radical reactions by using α-bromocarbonyl compounds (a tertiary alkyl source) and olefins or heteroatoms in the presence of a copper catalyst [17-19] . (beilstein-journals.org)
  • Nighttime reaction of nitrate radicals ( NO 3 ) with biogenic volatile organic compounds (BVOC) has been proposed as a potentially important but also highly uncertain source of secondary organic aerosol (SOA). (atmos-chem-phys.net)
  • 3. A method according to claim 1 wherein said free radical formation is induced chemically by addition of silver compounds. (google.co.uk)
  • Some of the less reactive of these species (such as superoxide ) can be converted by oxidoreduction reactions with transition metals or other redox cycling compounds including quinones into more aggressive radical species that can cause extensive cellular damage. (bionity.com)
  • Our goal is to screen chemical libraries to find compounds that prevent free-radical induced changes to these Parkinson's-related proteins. (bio-medicine.org)
  • 2-ethylhexyl acrylate is a useful feedstock for chemical synthesis, as it readily undergoes addition reactions with a wide range of organic and inorganic compounds. (express-press-release.net)
  • By showing that atmospheric air quality determines the concentration of radicals in lichens, we prove that electron paramagnetic resonance spectroscopy can be used for environmental monitoring in cities," says associate professor Svetlana Zhuravleva of the Department of Chemistry, MIPT. (eurekalert.org)
  • 1) The mechanism of manganese(III)-mediated radical reactions begins with the single-electron oxidation of a carbonyl compound to an α-oxoalkyl radical. (wikipedia.org)
  • Lewis theory notes but does not explain that certain magic numbers of electrons show stability: the Lewis octet, the 18 electron rule, the 4n + 2 rule, the two electron chemical bond, Lewis acids, Lewis bases, radicals, diradicals, VSEPR . (meta-synthesis.com)
  • This redox reaction is a single electron transfer (SET) process. (meta-synthesis.com)
  • When the reaction is defined with respect to the sodium atom the electron density decreases, and when defined with respect to the fluorine atom the electron density increases. (meta-synthesis.com)
  • I. In the past, organic free radicals have been divided into two classes: 1)The long-lived radicals which are stabilized by resonance, and for which, as for Wurster's salts (I), one can formulate several mesomeric forms with the lone electron in different positions. (docme.ru)
  • While reactions with unstabilised sulfonium and sulfoxonium ylides are known, most modern processes utilise stabilised versions, in which the negative charge is delocalised into one or more electron withdrawing groups. (springer.com)
  • For example, we recently reported that dicationic electrophiles, or superelelctrophiles, may undergo single electron transfer (SET) reactions with a suitable electron donor, eq 4 (J. Am. Chem. (niu.edu)
  • The one electron reduction leads to radical cation chemistry, and in the case of the oxazole derivative, a dimerization pathway. (niu.edu)
  • One-electron reduction state of O 2 , formed in many autoxidation reactions and by the electron transport chain . (bionity.com)
  • Three-electron reduction state, formed by Fenton reaction and decomposition of peroxynitrite . (bionity.com)
  • A radical is an atomic or molecular species having an unpaired, or odd, electron. (msu.edu)
  • Gomberg concluded that the colored solutions contained reactive triphenylmethyl free radicals, formed by thermal dissociation of their dimer (Keq = 2 10 -4 at 25º C). The exceptional stability of this carbon radical is attributed to odd electron delocalization into the three phenyl rings. (msu.edu)
  • Since the electron delocalization noted above places radical character at the para carbons of the phenyl groups, bonding to this relatively unhindered location is preferred, although at the cost of one benzene ring's aromaticity. (msu.edu)
  • But in some instances, each group retains a single electron, thereby forming two free radicals (assuming the original molecule had an even number of electrons. (universalclass.com)
  • An alkyl radical is more stable when the carbon with the unpaired electron is more highly substituted. (universalclass.com)
  • The five reactions described are electrophilic substitution reactions involving the generation of a powerful electrophile (electron pair acceptor) which subsequently attacks the electron rich Π (pi) electron system of the double bond. (docbrown.info)
  • Free radicals (FRs), species having unpaired electron in their outermost orbit play a pivotal role in the origin of life, physiological adaptation and biological evolution [ 1 ]. (ijpsonline.com)
  • who examined several features of the reaction relevant to the mechanism: stereochemistry, hydrogen isotope effect, initiation, inhibition, catalysis, intermediates and selectivity of hydrogen transfer. (wikipedia.org)
  • Particularly, this protocol utilizes the potent redox ability of photoexcited Hantzsch ester (HE) 13,14 to generate open-shell radical intermediates, thus facilitating the construction of two consecutive C-C bonds in one pot without the need for exogenous photocatalysts. (rsc.org)
  • Oxygen-derived free radicals and related oxidants are ubiquitous and short-lived intermediates formed in aerobic organisms throughout life. (pnas.org)
  • typically, radicals are reactive and short-lived intermediates. (pnas.org)
  • This thesis examines the characteristics of oxygen bonding that complicate the 0-0 bond formation reaction, and examines ligand platforms that can stabilize high valent metal oxo intermediates. (mit.edu)
  • Electrochemistry provides a new platform to conduct reactions through in situ generation of reactive intermediates under mild conditions, with broad applications to industrial synthesis. (europa.eu)
  • These intermediates will then undergo coupling, facilitated by nickel catalysis, to generate key carbon-carbon bonds, including challenging C(sp3)-C(sp3) bonds. (europa.eu)
  • Alkane and olefin radical cations, fundamental reaction intermediates in organic chemistry and in the radiation chemistry of hydrocarbons, have been characterized by time-resolved Fluorescence Detected Magnetic Resonance (FDMR) in pulse radiolysis of alkane liquids and solids from 30K to room temperature. (springer.com)
  • Furthermore, charged species such as carbocations, carbanions, conjugate acids and conjugate bases are often intermediates on the reaction path, the overall transformation taking place in two or more discrete steps. (msu.edu)
  • In terrestrial organisms, sensitivity to the Earth's magnetic field is mediated by at least two different magnetoreception mechanisms, one involving biogenic ferromagnetic crystals (magnetite/maghemite) and the second involving a photo-induced biochemical reaction that forms long-lasting, spin-coordinated, radical pair intermediates. (biologists.org)
  • Copper(II) acetate is sometimes used as a co-oxidant to assist in the oxidation of intermediate radicals to carbocations. (wikipedia.org)
  • Pathways available to the adduct radical include further oxidation to a carbocation (and subsequent β-elimination or trapping with a nucleophile) and hydrogen abstraction to generate a saturated carbonyl compound containing a new carbon-carbon bond. (wikipedia.org)
  • Copper(II) acetate is sometimes needed to facilitate the oxidation of adduct radicals to carbocations. (wikipedia.org)
  • Yields of these reactions are generally moderate, particularly in the intermolecular case, but tandem intramolecular radical cyclizations initiated by Mn(III) oxidation may generate complex carbocyclic frameworks. (wikipedia.org)
  • The fate of 2 is primarily determined by reaction conditions-in the presence of copper(II) acetate, this intermediate undergoes further oxidation to a carbocation and may eliminate to form β,γ-unsaturated ketone 4. (wikipedia.org)
  • For every reduction reaction which takes place there must be a concurrent oxidation. (meta-synthesis.com)
  • The Co complex undergoes a ligand centered oxidation event to yield the first structurally characterized NacNac radical cation. (mit.edu)
  • This is a complexformulation of photocatalytic oxidation technology.This relatively new field of science uses a water-based sustainable 'green' ultra(nano) TiO2 liquid, to form a long lasting transparent (clear) coating that iscapable of producing powerful oxidizing hydroxyl and other radicals upon beingirradiated by light-even low levels, such as moonlight or candlelight, givesufficient intensity for the catalyst to work, albeit slowly. (slideshare.net)
  • The detection of 3-chlorotyrosine in human atherosclerotic lesions indicates that halogenation reactions catalyzed by the myeloperoxidase system of phagocytes constitute one pathway for protein oxidation in vivo. (jci.org)
  • The results of the present study revealed that 5-[(4-chlorophenoxy)methyl]-1,3,4-oxadiazole-2-thiol has the propensity to abrogate oxidation by inducing endogenous defence system and preventing radical chain reactions, hence might be considered a potential antioxidant for further investigations. (ijpsonline.com)
  • Protection against injury due to the FRs is possible only by ample intake of antioxidants, which delay or inhibit the oxidation of biomolecules by their reducing activity, free radical scavenging, complexation of pro-oxidant metals, and quenching of singlet oxygen. (ijpsonline.com)
  • In the next reaction step these peroxides and hydroperoxides degrade into low molecular oxidation products such as aldehydes, alcohols, ketones, acids and high molecular oligomers. (greencarcongress.com)
  • But when ions and radicals are in excess, this disrupts cell metabolism and interferes with the natural balance of redox reactions by damaging proteins, nucleic acids, and the lipids in the cell membrane. (eurekalert.org)
  • Their ions are capable of entering redox reactions, whereby they can give up or take on electrons with relative ease. (eurekalert.org)
  • Alloxan and the product of its reduction, dialuric acid, establish a redox cycle with the formation of superoxide radicals. (omicsonline.org)
  • When the set of chemical reactions is analysed in terms of Lewis theory and FMO theory it is discovered that there are five general types of electronic reaction mechanism: Lewis acid/base, Radical, Photo, Diradical and Redox. (meta-synthesis.com)
  • A typical example of a redox process would be the reaction of sodium and fluorine to give sodium fluoride, NaF. (meta-synthesis.com)
  • Recent advances are then introduced covering the reaction mechanisms, specific functionalization methods, and electrochemical performances of redox species classified by their molecular structures. (rsc.org)
  • These reactive species participate in redox reactions leading to oxidative modifications in biomolecules, among which proteins and lipids are preferential targets. (pnas.org)
  • Disturbances in this normal redox state can cause toxic effects through the production of peroxides and free radicals that damage all components of the cell, including proteins , lipids , and DNA . (bionity.com)
  • By further exploring O 2 's free radical "quantum quirkiness" including emergent quantum physiological phenomena, our understanding of precisely how the human brain senses O 2 deprivation (hypoxia) and the elaborate redox-signaling defense mechanisms that defend O 2 homeostasis has the potential to offer unique insights into the pathophysiology and treatment of human brain disease. (springer.com)
  • In: Fischer H., Heimgartner H. (eds) Organic Free Radicals. (springer.com)
  • Such radicals acting on DNA could produce mutations, altering the transcrition into mRNA and the translation into proteins. (madsci.org)
  • In addition free radicals can affect the membranes by causing peroxidation of lipids and proteins. (madsci.org)
  • When biological systems are exposed to hydroxyl radicals, they can cause damage to cells, including those in humans, where they can react with DNA , lipids , and proteins . (wikipedia.org)
  • Model peptides in buffer as well as native proteins in human blood plasma additionally exhibit properties in keeping with the homocystamide-facilitated hydrogen atom transfer and resultant carbon-centered radicals. (pnas.org)
  • NO), a free radical and weak oxidant, represents a master physiological regulator via reversible interactions with heme proteins. (pnas.org)
  • We recently identified proteins that undergo chemical reactions in th. (bio-medicine.org)
  • We recently identified proteins that undergo chemical reactions in the brains of patients with Parkinson's disease," said Dr. Lipton. (bio-medicine.org)
  • These chemical reactions may contribute to the disease process and the chemically-modified proteins may serve as biomarkers for disease progression. (bio-medicine.org)
  • Many radicals react rapidly with proteins resulting in side-chain modification, backbone fragmentation, aggregation, and changes in structure and function. (ovid.com)
  • formed on peptides and proteins undergo rapid recombination reactions to form Trp-Trp cross-linked species. (ovid.com)
  • A brief account is given on the reaction of carbon-centered radicals with the nucleobases. (springer.com)
  • Alpha-amino acid carbon-centered radicals, well-known precursors of protein carbonyls, are shown to form via a hydrogen atom transfer process involving thiolactone-derived homocystamides. (pnas.org)
  • Paneth's methyl radicals dissolving lead mirrors: 1929. (docme.ru)
  • 2) The short-lived radicals like methyl or phenyl which do not enjoy such stabilization and for which only one mesomeric form is possible. (docme.ru)
  • Consequently, nulceophilic attack occurs at the distant site due to charge migration (eq 5), while a similar reaction involving a methyl group shows no tendency to undergo charge migration (eq 6). (niu.edu)
  • Thus, a methyl radical (·CH 3 ) is less stable than a monosubstituted carbon radical (a primary radical), which is less stable than secondary and tertiary radicals. (universalclass.com)
  • The methyl radical then attacks a diatomic chlorine molecule to form methyl chloride (chloromethane) and a new chlorine radical. (universalclass.com)
  • It is known to undergo free-radical solution polymerization with methyl methacrylate to form pressure-sensitive adhesives. (express-press-release.net)
  • The pathway to fulvene advocates that, in the allene-1-propynyl system, the methyl group of the 1-propynyl reactant is actively engaged in the reaction mechanism to form fulvene. (unboundmedicine.com)
  • Using a degradation rate constant of 2.27E-12 cm3/molecule/ses the half life of VDF AOPWIN ™ v v1.92a (U.S. EPA, 2008), based on a 12-hr day with an OH radical concentration of 1.5E6 OH/cm3, is 4.7 days (see Annexes 2 and 3 for the QMRF and QPRF). (europa.eu)
  • Reaction products of the compositions of this invention exhibit superior resistance of thermal degradation. (google.com)
  • The -ketoaldehyde methylglyoxal (MG), formed endogenously as a by-product of the glycolytic pathway, by degradation of triosephosphates or nonenzymatically by sugar fragmentation reactions, is the most potent precursor of AGE formation [ 10 ]. (hindawi.com)
  • Alpha-Terpinyl acetate undergoes in air rapid degradation after reaction with hydroxyl radicals or ozone. (europa.eu)
  • Model contaminant degradation experiments and UV light absorption measurements of ozonated water samples in both ozone (O 3 ) and peroxone (H 2 O 2 /O 3 ) reaction systems in pure water, river water, wastewater effluent, and solutions containing humic acid show that the contactor system can be used to generate information on the reactivity of ozone with different water matrices. (mdpi.com)
  • The degradation of VDF in the lower atmosphere will be initiated mainly by reaction with naturally occurring hydroxyl radicals. (europa.eu)
  • This reaction will therefore make a negligible contribution to the atmospheric degradation of VDF. (europa.eu)
  • Carbonyl fluoride (COF2) and formaldehyde (HCHO) are predicted to be degradation products, irrespective of the regioselectivity of the addition of OH radicals to VDF (ECETOC, 2005). (europa.eu)
  • UV radiation causes photooxidative degradation which results in breaking of the polymer chains, produces free radical and reduces the molecular weight, causing deterioration of mechanical properties and leading to useless materials, after an unpredictable time. (scribd.com)
  • The cause of undesired fuel instability are unsaturated hydrocarbons: They undergo autoxidation forming alkyl and peroxy radicals which can react with oxygen to form peroxide or hydroperoxide. (greencarcongress.com)
  • One of the very important reactions of peroxyl radicals are there reaction with NO, produced in the photochemical dissociation of NO2. (scribd.com)
  • A photoinitiator is a molecule that creates reactive species such as free radicals, cations, or anions when exposed to radiation - UV or visible. (openpr.com)
  • VDF undergoes reactions with hydroxyl radicals in the atmosphere, the calculated rate constant with is 2.27E-12 cm3/molecule.sec. (europa.eu)
  • Dissociation and Ion-Molecule Reactions of Alkane Radical Cations. (springer.com)
  • Werst D.W., Percy L.T., Trifunac A.D. (1988) Dissociation and Ion-Molecule Reactions of Alkane Radical Cations. (springer.com)
  • 7. A method as described in claim 6 wherein said free radical forming group comprises a chemical capable of forming a free radical that is covalently bound to either the ligand or ligand recognition molecule. (google.co.uk)
  • Absorbed by a molecule from this radiation can result in the formation of active species, thus initiating photochemical reactions that lead to the noxious products characteristic of smog. (scribd.com)
  • Needless to say, any molecule that has an odd number of electrons is by definition a free radical. (universalclass.com)
  • Free hydrogen radicals diffuse very easily through the polymer matrix and combine in pairs or abstract hydrogen atoms from polymer molecule. (scribd.com)
  • Properties of the base radical cations have been studied in model systems using SO 4 − radical to oxidize the nucleobases in aqueous solution. (springer.com)
  • The pK a values of some nucleobase radical cations are reported, so are the ensuing reactions of the thymidine radical cation with water. (springer.com)
  • The Hofmann-Löffler-Freytag reaction proceeds via an intramolecular hydrogen atom transfer to a nitrogen-centered radical and is an example of a remote intramolecular free radical C-H functionalization. (wikipedia.org)
  • The amminium radical intramolecularly abstracts a sterically favored hydrogen atom to afford an alkyl radical which, in a chain reaction, abstracts chlorine from another N-chloroammonium ion to form an alkyl chloride and a new amminium radical. (wikipedia.org)
  • Third, the Hcy thiyl radical can undergo a kinetically favored hydrogen atom transfer (HAT) reaction to afford an alpha-amino carbon-centered radical ( Scheme 2 ). (pnas.org)
  • The C-C triple bond of an alkyne is suitable for addition reactions, whereas the terminal hydrogen atom is a good target for cross-coupling by using Sonogashira and related coupling reactions [2-4] . (beilstein-journals.org)
  • Enhanced ATP dephosphorylation after streptozotocin treatment supplies a substrate for xanthine oxidase resulting in the formation of superoxide radicals. (omicsonline.org)
  • The Hofmann-Löffler reaction (also referred to as Hofmann-Löffler-Freytag reaction, Löffler-Freytag reaction, Löffler-Hofmann reaction, as well as Löffler's method) is an organic reaction in which a cyclic amine 2 (pyrrolidine or, in some cases, piperidine) is generated by thermal or photochemical decomposition of N-halogenated amine 1 in the presence of a strong acid (concentrated sulfuric acid or concentrated CF3CO2H). (wikipedia.org)
  • Although the Hofmann-Löffler-Freytag reaction was to become a general and expeditious process for the formation of pyrrolidines, it was not until about 25 years after Hofmann's work that further examples of the reaction appeared in the literature. (wikipedia.org)
  • A number of chemical reactions is responsible for the formation of ozone. (naturalnews.com)
  • Throughout life, bone tissue undergoes a continuous process of resorption and formation. (hindawi.com)
  • It promotes the formation of radicals from dialkyl malonates, which undergo substitution reactions with furans and thiophenes. (alfa.com)
  • Treatment of LDL with reagent HOCl resulted in 3-chlorotyrosine formation, implicating HOCl as an intermediate in the enzymatic reaction pathway. (jci.org)
  • 11. A method according to claim 10 wherein free radical formation is induced by heat. (google.co.uk)
  • and formation of nucleobase/nucleotide anion radicals at increasing nucleobase/nucleotide concentrations present direct evidence for the earliest step in reductive DNA damage by ionizing radiation. (sciencemag.org)
  • Radicals have an important role in many reactions, a few of which we will discuss here, including the formation of polymers (polymerization). (universalclass.com)
  • L'action des ions chlorite sur le charbon actif peut conduire à la formation de radicaux à la surface du charbon actif ou en solution capables de réagir avec les composés organiques pour former les sous-produits observés. (erudit.org)
  • This oxygen promoted the formation of toxic free radicals, which exposes modern organisms and cells to massive oxidative stress. (scitechdaily.com)
  • On the other hand, in the allene system, our experimental data exhibit the formation of the fulvene (c-C5H4CH2) isomer via a six-step reaction sequence with two higher energy isomers-hexa-1,2-dien-4-yne (H2CCCHCCCH3) and hexa-1,4-diyne (HCCCH2CCCH3)-also predicted to be formed based on our statistical calculations. (unboundmedicine.com)
  • This review article aims to integrate some early and remarkable discoveries in the field, with more recent developments that helped to define a causative role of oxygen radicals, nitric oxide, and peroxynitrite in human physiology and pathology. (pnas.org)
  • The toxicity of endogenously formed oxygen radicals in biological systems was initially substantiated in studies of "oxygen poisoning" parallel to the discovery of the mechanisms of radiation-induced injury ( 1 ). (pnas.org)
  • Free Radical Reactions of Carbohydrates as Studied by Radiation 'lèchniques. (springer.com)
  • The mechanism of PS photolysis in the solid state (film) depends on the mobility of free radicals in the polymer matrix and their bimolecular recombination. (scribd.com)
  • Free radicals and their precursors can be produced endogenously through normal metabolic processes or exogenously through air pollutants, smoking and other sources. (nutrametrix.com)
  • The mechanism of the Hofmann-Löffler-Freytag reaction was first investigated by S. Wawzonek, who studied cyclization reactions of various N-halogenated amines. (wikipedia.org)
  • Alternatively, H2O2 can undergo Fenton or Haber-Weiss chemistry, reacting with Fe2+/Fe3+ ions to form toxic hydroxyl radicals (-.OH). (hmdb.ca)
  • The limiting aspect of this reaction is the oxygen forming reaction, which can be catalyzed by transition metal species with varying degrees of efficiency. (mit.edu)
  • Planar bis-pdiketiminate (NacNac) complexes were synthesized by reaction of acetonitrile with Fe and Co mesityl species. (mit.edu)
  • A particularly destructive aspect of oxidative stress is the production of reactive oxygen species, which include free radicals and peroxides. (bionity.com)
  • Many doubted that such open-valenced species could exist, although there was circumstantial evidence for their participation in gas phase reactions. (msu.edu)
  • To produce a methylperoxyl radical (H3COO) This is a strongly oxidizing, reactive species. (scribd.com)
  • Reactive oxygen species (ROS) are a family of oxygen-derived free radicals that are produced in mammalian cells under normal and pathologic conditions. (hmdb.ca)
  • Nitric oxide free radical (NO.) is a very important signalling species that regulates relaxation and proliferation of vascular smooth muscles, leukocytes adhesion, platelets aggregation, angiogenesis, thrombosis, vascular tone and haemodynamics [ 2 ]. (ijpsonline.com)
  • Mammalian cells being constantly fortified with oxygen produce oxygen free radicals (OFR), hydroxyl (OH-) and superoxide (O 2 -), and reactive oxygen species (ROS), NO., hypochlorous acid, hydrogen peroxide (H 2 O 2 ) and peroxynitrite as a by-product of aerobic metabolism [ 3 , 4 ]. (ijpsonline.com)
  • Since, the rate of production and removal of FRs is balanced by reactions involving enzymes such as catalase, glutathione peroxidase, glutathione reductase and superoxide dismutase, and non-enzymatic processes such as thioredoxin, thiols and disulphidebonding, these species do not necessarily present any threat to the body under normal physiological conditions [ 5 ]. (ijpsonline.com)
  • In some polynucleotides radical transfer from the base radical to the sugar moiety occurs with the consequence of strand breakage and base release. (springer.com)
  • The reaction of HTL with the ε-amine moiety of protein Lys residues results in a posttranslational modification known as Hcy- N -protein ( 7 , 13 ). (pnas.org)
  • Moreover, the reaction of α-bromocarbonyl compound 2 and an alkyne 4 possessing a carboxamide moiety undergoes tandem alkyl radical addition/C-H coupling to produce indolinone derivative 5 . (beilstein-journals.org)
  • One type of "free-radical reaction", alkane halogenation has already been described. (msu.edu)
  • These data clearly demonstrate that halogenation reactions take place in the GAC bed and that a fraction of the total amount of phenol or p nitrophenol removed can be due to chemical reactions. (erudit.org)
  • The exact mechanism of luminol chemiluminescence is a complex multi-step reaction, especially in aqueous conditions. (wikipedia.org)
  • The results, presented below, pointed conclusively to a free-radical chain mechanism involving intramolecular hydrogen transfer as one of the propagation steps. (wikipedia.org)
  • The body's natural defense mechanism to neutralize free radicals is the production and regeneration of antioxidants. (nutrametrix.com)
  • And, in particular, why has natural selection produced a compass mechanism based on a light-dependent radical pair mechanism (RPM) when a magnetite-based receptor is well suited to perform this function? (biologists.org)
  • it can be seen that there are five common and general types of reaction chemistry behaviour . (meta-synthesis.com)
  • No other reaction chemistry is so broad, varied, or central to how we understand chemical reactivity. (meta-synthesis.com)
  • Read more about Lewis acid/base reaction chemistry here . (meta-synthesis.com)
  • A considerable number of oxidising agents and reducing agents have been added to The Chemical Thesaurus reaction chemistry database . (meta-synthesis.com)
  • This chemistry is fundamentally important in the design of molecular electronics, but it can influence the regiochemistry of some reactions. (niu.edu)
  • Reactions of this kind have received increasing attention, thanks to their great importance in industrial chemistry. (msu.edu)
  • Indeed, the study of free-radical polymerization of alkene monomers has opened the door to modern polymer chemistry. (msu.edu)
  • This occurs at physiological temperature upon exposure to air without any added oxidants or free-radical initiators. (pnas.org)
  • Excessive free radicals are generated in body due to unbalanced oxidants and antioxidants ratio which results into oxidative stress. (biomedcentral.com)
  • In this report, we found that the reaction of 3 equivalents of terminal alkyne 1 (aryl substituted alkyne) and an α-bromocarbonyl compound 2 (tertiary alkyl radical precursor) undergoes tandem alkyl radical addition/Sonogashira coupling to produce 1,3-enyne compound 3 possessing a quaternary carbon in the presence of a copper catalyst. (beilstein-journals.org)
  • Some radicals, such as nitric oxide (NO), are relatively stable, but most are so reactive that their isolation and long-term study is not possible under normal laboratory conditions. (msu.edu)
  • Herein, we seek to combine the fields of electrochemistry and cross-coupling reactions, using an electric current to catalytically generate alkylzinc reagents and reactive alkyl radicals. (europa.eu)
  • This added stability means that sulfonium/sulfoxonium ylides can be used as practical, bench-stable reagents and enables the development of reactions of increased complexity. (springer.com)
  • High-energy radiation and photons have a reputation for being clean reagents, in that they do not leave any of their fragments in the reaction medium. (pcimag.com)
  • These special reagents, though expensive, were unique in their effect and occupied a special position in the arena of chemical reactions. (pcimag.com)
  • As thiyl radicals are known to also undergo the reverse reaction, i.e. (springer.com)
  • Hcy thiyl radical undergoes a kinetically favored intramolecular HAT to form a reducing alpha-amino carbon radical. (pnas.org)
  • They may abstract hydrogen from the near surrounding or combine with a polymer radical or with hydrogen radicals. (scribd.com)
  • The reaction of e aq − with the nucleobases yields radical anions. (springer.com)
  • Intermolecular reactions between ketones/aldehydes and alkenes tend to result in low yields. (wikipedia.org)
  • A variety of substitution patterns may be employed for this transformation, and yields are generally higher than intermolecular coupling reactions. (wikipedia.org)
  • To generate NO2, which can undergo photo-dissociation, re-initiating the series of chin reactions by which smog is formed. (scribd.com)
  • Deuterium-labeling experiments shed light on the productive reaction pathways of the E- and Z-isomers. (imperial.ac.uk)
  • The revision notes include full diagrams and explanation of the mechanisms and the 'molecular' equation and reaction conditions and other con-current reaction pathways and products are also explained for the reaction mechanisms of aromatic hydrocarbons like benzene and methylbenzene. (docbrown.info)
  • This oxygen-based chemical reaction releases chemical radicals into the air. (naturalnews.com)
  • Photoinitiators have the capacity to catalyze or initiate chemical reactions, which result in remarkable changes in the physical properties and solubility of various suitable formulations. (openpr.com)
  • When illuminated, it can lower thechemical activation energy to enhance chemical reaction or accelerate thereaction rate. (slideshare.net)
  • However, the catalyst itself will not undergo changes and itsstructure will not be damaged as a result of the chemical reaction. (slideshare.net)
  • Carbonyl fluoride will not be photolysed or undergo chemical reaction in the gas phase of the atmosphere, but will be removed by uptake into cloud droplets and subsequent hydrolysis to CO2 and HF, within a few weeks (Cox et al, 1995). (europa.eu)
  • Specifically, the investigators will examine chemical reactions that alter protein function. (bio-medicine.org)
  • They found that the newer amino acids had become systematically softer, i.e., more readily reactive or prone to undergo chemical changes. (scitechdaily.com)
  • The new amino acids underwent chemical reactions with the free radicals and thus scavenged them in an efficient manner. (scitechdaily.com)
  • X1A1), along with their (partially) deuterated counterparts were explored at collision energies of 37 kJ mol-1, exploiting crossed molecular beams to unravel the chemical reaction dynamics to synthesize distinct C6H6 isomers under single collision conditions. (unboundmedicine.com)
  • Because both reactions are barrierless and exoergic and all transition states are located below the energy of the separated reactants, the hydrogen-deficient C6H6 isomers identified in our investigation are predicted to be synthesized in low-temperature environments, such as in hydrocarbon-rich atmospheres of planets and their moons such as Titan along with cold molecular clouds such as Taurus Molecular Cloud-1. (unboundmedicine.com)
  • Under the "on water" reaction conditions, extremely unreactive β,β-disubstituted nitroalkenes smoothly underwent enantioselective Michael addition reactions with dithiomalonates using a chiral squaramide catalyst, affording both enantiomers of highly enantioenriched Michael adducts with all-carbon-substituted quaternary centers. (imperial.ac.uk)
  • Hydrogen probe experiments generate: Lewis acids, Lewis bases, Lewis acid/base complexes radicals and metals, which are reducing agents. (meta-synthesis.com)
  • If there is sunlight present, the radicals cause other VOCs to react with oxides of nitrogen (NOx), thereby producing ozone. (naturalnews.com)
  • In their study, the Chinese-American research team found that PM 2.5 and other particulate matter did have at least one beneficial purpose: They absorbed the radicals responsible for kicking off ozone production. (naturalnews.com)
  • The DT50-values after reaction with hydroxyl radicals and ozone are 1.36 hours and 0.64 hours, respectively. (europa.eu)
  • Figure 1 (a) Example of the initial reactions of limonene with ozone to form limononic acid from the anti-CI * via the hot acid channel and (b) the collisional stabilisation channel (Vereecken and Francisco, 2012). (atmos-chem-phys.net)
  • H2O2 and free radicals are produced as a result of certain oxidative reactions involved in the break down of amino acids and fats. (madsci.org)
  • H2O2 also reacts with the superoxide radical to produce even more reactive free radicals. (madsci.org)
  • LDL exposed to the complete myeloperoxidase-H2O2-Cl- system underwent chlorination of its protein tyrosyl residues. (jci.org)
  • Produced O2- can react with other radicals, such as NO, or spontaneously dismutate to produce hydrogen peroxide (H2O2). (hmdb.ca)
  • Once formed, H2O2 can undergo various reactions, both enzymatic and nonenzymatic. (hmdb.ca)
  • Although there are many reports on alkyne transformations, one recent development in this area has been the reaction of alkynes with tertiary alkyl electrophiles to produce functionalized quaternary carbon atoms via addition [5-10] or coupling [11-16] . (beilstein-journals.org)
  • The atomic resonance absorptions of O- and H-atoms in the reaction of shock-heated H 2 /O 2 /CO/Ar(1/1/1/97 and 0.2/1/1/97.8) mixtures were observed over a relatively low temperature range from 1000 to 1400 K. The induction times, determined from the absorptions, were investigated by means of computer modeling which included a sensitivity test. (go.jp)
  • Selectivity is high for the radical addition that leads to the more stable adduct radical, and trans lactones are selectively formed from either cis or trans acyclic alkenes. (wikipedia.org)
  • The Heck reaction is the palladium catalyzed cross-coupling reaction between alkenes, and aryl or vinyl halides (or triflates) to afford substituted alkenes.1,2 It is a useful carbon-carbon bond form. (sigmaaldrich.com)
  • In our continuing efforts to pursue radical functionalization of alkenes, 10 we envisioned that a light-induced, sequential radical-addition/radical-coupling protocol between alkenes and pyridines could provide a generic solution to this challenging carbopyridylation of alkenes. (rsc.org)
  • Given the importance of trifluoromethyl groups in pharmaceuticals and agrochemicals 11 as well as elegant progress in radical trifluoromethylation of alkenes, 12 we focused on the development of pyridyl functionalization of alkenes with concomitant construction of C(sp 3 )-CF 3 bonds. (rsc.org)
  • pmid: 28888349] undergone an extensive collateral venous the dorsal venous complex is completely separated, it more the study, fossa et al.50 253 nr nr 735 30 plicated ileum 55.3 nr nr. (goodbelly.com)
  • Based on this evidence, they correctly proposed that the reaction proceeds via a radical chain reaction pathway. (wikipedia.org)
  • Photodegradation will account for removal of 1,2-dichloropropane from the atmosphere, based on a calculated half-life of 34.9 days at 25 C. The reaction with OH radicals proceeds via net hydrogen abstraction from C-H bonds. (europa.eu)
  • Because of the limited functional group compatibility of Mn(OAc)3, radical couplings employing this reagent have mainly been applied to the synthesis of hydrocarbon natural products, such as pheromones. (wikipedia.org)
  • Following the cleavage step above for chlorine-whether performed at high temperature or in the presence of light-the chlorine free radical attacks methane as shown below. (universalclass.com)
  • Note that these two steps-which constitute the so-called propagation steps of the reaction-do not change the concentration of chlorine radicals. (universalclass.com)
  • Dinuclear μ -hydroxo-bridged complexes formed by reaction of trans[ArNi(PR 3 ) 2 X] with hydroxide are not directly involved in transmetalation, but they rather act as a resting state for the catalyst. (ens.fr)
  • Formed by radical reactions with cellular components such as lipids and nucleobases . (bionity.com)
  • Feruary 5th,1996, she underwent radical gastrectomy. (bio.net)