Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Cations, Divalent: Positively charged atoms, radicals or groups of atoms with a valence of plus 2, which travel to the cathode or negative pole during electrolysis.Cations, Monovalent: Positively charged atoms, radicals or group of atoms with a valence of plus 1, which travel to the cathode or negative pole during electrolysis.Organic Cation Transport Proteins: A family of proteins involved in the transport of organic cations. They play an important role in the elimination of a variety of endogenous substances, xenobiotics, and their metabolites from the body.Organic Cation Transporter 1: An organic cation transporter found in kidney. It is localized to the basal lateral membrane and is likely to be involved in the renal secretion of organic cations.Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.Hypertension, Pulmonary: Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.TRPC Cation Channels: A subgroup of TRP cation channels that contain 3-4 ANKYRIN REPEAT DOMAINS and a conserved C-terminal domain. Members are highly expressed in the CENTRAL NERVOUS SYSTEM. Selectivity for calcium over sodium ranges from 0.5 to 10.Ion Channels: Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.Manganese: 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)Cation Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.Kinetics: The rate dynamics in chemical or physical systems.Hydrogen-Ion Concentration: 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)Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Rubidium: An element that is an alkali metal. It has an atomic symbol Rb, atomic number 37, and atomic weight 85.47. It is used as a chemical reagent and in the manufacture of photoelectric cells.Hardness: The mechanical property of material that determines its resistance to force. HARDNESS TESTS measure this property.Lithium: An element in the alkali metals family. It has the atomic symbol Li, atomic number 3, and atomic weight [6.938; 6.997]. Salts of lithium are used in treating BIPOLAR DISORDER.TRPV Cation Channels: A subgroup of TRP cation channels named after vanilloid receptor. They are very sensitive to TEMPERATURE and hot spicy food and CAPSAICIN. They have the TRP domain and ANKYRIN repeats. Selectivity for CALCIUM over SODIUM ranges from 3 to 100 fold.Cation Exchange Resins: High molecular weight insoluble polymers which contain functional anionic groups that are capable of undergoing exchange reactions with cations.Cesium: A member of the alkali metals. It has an atomic symbol Cs, atomic number 50, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.Metals, Alkali: Metals that constitute group 1(formerly group Ia) of the periodic table. They are the most strongly electropositive of the metals. Note that HYDROGEN is not considered an alkali metal even though it falls under the group 1 heading in the periodic table.Ion Transport: The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.Cell Membrane Permeability: A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.Cyclic Nucleotide-Gated Cation Channels: A subgroup of cyclic nucleotide-regulated ION CHANNELS within the superfamily of pore-loop cation channels. They are expressed in OLFACTORY NERVE cilia and in PHOTORECEPTOR CELLS and some PLANTS.Barium: An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.Betaine: A naturally occurring compound that has been of interest for its role in osmoregulation. As a drug, betaine hydrochloride has been used as a source of hydrochloric acid in the treatment of hypochlorhydria. Betaine has also been used in the treatment of liver disorders, for hyperkalemia, for homocystinuria, and for gastrointestinal disturbances. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1341)Ion Channel Gating: The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Quaternary Ammonium Compounds: Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.Edetic Acid: A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Flufenamic Acid: An anthranilic acid derivative with analgesic, anti-inflammatory, and antipyretic properties. It is used in musculoskeletal and joint disorders and administered by mouth and topically. (From Martindale, The Extra Pharmacopoeia, 30th ed, p16)Metals: Electropositive chemical elements characterized by ductility, malleability, luster, and conductance of heat and electricity. They can replace the hydrogen of an acid and form bases with hydroxyl radicals. (Grant & Hackh's Chemical Dictionary, 5th ed)Calcium Channels: Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Lanthanum: Lanthanum. The prototypical element in the rare earth family of metals. It has the atomic symbol La, atomic number 57, and atomic weight 138.91. Lanthanide ion is used in experimental biology as a calcium antagonist; lanthanum oxide improves the optical properties of glass.Cobalt: A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Adenosine Triphosphate: An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Tetraethylammonium: A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)Zinc: A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.Catecholamine Plasma Membrane Transport Proteins: A group of membrane transport proteins that transport biogenic amine derivatives of catechol across the PLASMA MEMBRANE. Catecholamine plasma membrane transporter proteins regulate neural transmission as well as catecholamine metabolism and recycling.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.Osmolar Concentration: The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Nickel: A trace element with the atomic symbol Ni, atomic number 28, and atomic weight 58.69. It is a cofactor of the enzyme UREASE.Salts: Substances produced from the reaction between acids and bases; compounds consisting of a metal (positive) and nonmetal (negative) radical. (Grant & Hackh's Chemical Dictionary, 5th ed)Gadolinium: Gadolinium. An element of the rare earth family of metals. It has the atomic symbol Gd, atomic number 64, and atomic weight 157.25. Its oxide is used in the control rods of some nuclear reactors.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.TRPP Cation Channels: A subgroup of TRP cation channels that are widely expressed in various cell types. Defects are associated with POLYCYSTIC KIDNEY DISEASES.Antiporters: Membrane transporters that co-transport two or more dissimilar molecules in the opposite direction across a membrane. Usually the transport of one ion or molecule is against its electrochemical gradient and is "powered" by the movement of another ion or molecule with its electrochemical gradient.Egtazic Acid: A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.Sodium-Potassium-Exchanging ATPase: An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Cadmium: An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.Metals, Rare Earth: A group of elements that include SCANDIUM; YTTRIUM; and the LANTHANOID SERIES ELEMENTS. Historically, the rare earth metals got their name from the fact that they were never found in their pure elemental form, but as an oxide. In addition they were very difficult to purify. They are not truly rare and comprise about 25% of the metals in the earth's crust.Metals, Alkaline Earth: Metals that constitute the group 2 (formerly group IIa) of the periodic table.Permeability: Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.Cytoplasmic Streaming: The movement of CYTOPLASM within a CELL. It serves as an internal transport system for moving essential substances throughout the cell, and in single-celled organisms, such as the AMOEBA, it is responsible for the movement (CELL MOVEMENT) of the entire cell.Sodium Chloride: A ubiquitous sodium salt that is commonly used to season food.Potassium Chloride: A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.Thallium: A heavy, bluish white metal, atomic number 81, atomic weight [204.382; 204.385], symbol Tl.Oocytes: Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).Calcium Chloride: A salt used to replenish calcium levels, as an acid-producing diuretic, and as an antidote for magnesium poisoning.Tromethamine: An organic amine proton acceptor. It is used in the synthesis of surface-active agents and pharmaceuticals; as an emulsifying agent for cosmetic creams and lotions, mineral oil and paraffin wax emulsions, as a biological buffer, and used as an alkalizer. (From Merck, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p1424)Environmental Pollutants: Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Chelating Agents: Chemicals that bind to and remove ions from solutions. Many chelating agents function through the formation of COORDINATION COMPLEXES with METALS.Ion Exchange: Reversible chemical reaction between a solid, often one of the ION EXCHANGE RESINS, and a fluid whereby ions may be exchanged from one substance to another. This technique is used in water purification, in research, and in industry.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Transient Receptor Potential Channels: A broad group of eukaryotic six-transmembrane cation channels that are classified by sequence homology because their functional involvement with SENSATION is varied. They have only weak voltage sensitivity and ion selectivity. They are named after a DROSOPHILA mutant that displayed transient receptor potentials in response to light. A 25-amino-acid motif containing a TRP box (EWKFAR) just C-terminal to S6 is found in TRPC, TRPV and TRPM subgroups. ANKYRIN repeats are found in TRPC, TRPV & TRPN subgroups. Some are functionally associated with TYROSINE KINASE or TYPE C PHOSPHOLIPASES.Ionophores: Chemical agents that increase the permeability of biological or artificial lipid membranes to specific ions. Most ionophores are relatively small organic molecules that act as mobile carriers within membranes or coalesce to form ion permeable channels across membranes. Many are antibiotics, and many act as uncoupling agents by short-circuiting the proton gradient across mitochondrial membranes.Tetraethylammonium CompoundsProtein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.1-Methyl-4-phenylpyridinium: An active neurotoxic metabolite of 1-METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE. The compound reduces dopamine levels, inhibits the biosynthesis of catecholamines, depletes cardiac norepinephrine and inactivates tyrosine hydroxylase. These and other toxic effects lead to cessation of oxidative phosphorylation, ATP depletion, and cell death. The compound, which is related to PARAQUAT, has also been used as an herbicide.Gramicidin: A group of peptide antibiotics from BACILLUS brevis. Gramicidin C or S is a cyclic, ten-amino acid polypeptide and gramicidins A, B, D are linear. Gramicidin is one of the two principal components of TYROTHRICIN.Potassium Channels: Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Valinomycin: A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Amiloride: A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)Thermodynamics: A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)Escherichia coli: 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.Pyridinium CompoundsElectrochemistry: The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Cesium Isotopes: Stable cesium atoms that have the same atomic number as the element cesium, but differ in atomic weight. Cs-133 is a naturally occurring isotope.Onium Compounds: Ions with the suffix -onium, indicating cations with coordination number 4 of the type RxA+ which are analogous to QUATERNARY AMMONIUM COMPOUNDS (H4N+). Ions include phosphonium R4P+, oxonium R3O+, sulfonium R3S+, chloronium R2Cl+Molecular Structure: 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.Cholecystectomy, Laparoscopic: Excision of the gallbladder through an abdominal incision using a laparoscope.Cells, Cultured: 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.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Water: 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)Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels: A subgroup of cyclic nucleotide-regulated ION CHANNELS of the superfamily of pore-loop cation channels that are opened by hyperpolarization rather than depolarization. The ion conducting pore passes SODIUM, CALCIUM, and POTASSIUM cations with a preference for potassium.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Sodium Channels: Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.Spermidine: A polyamine formed from putrescine. It is found in almost all tissues in association with nucleic acids. It is found as a cation at all pH values, and is thought to help stabilize some membranes and nucleic acid structures. It is a precursor of spermine.Static Electricity: The accumulation of an electric charge on a objectTrityl CompoundsAdenosine Triphosphatases: A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.Equilibrative Nucleoside Transport Proteins: A class of sodium-independent nucleoside transporters that mediate the facilitative transport of NUCLEOSIDES.Cattle: 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.Cholecystectomy: Surgical removal of the GALLBLADDER.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Spermine: A biogenic polyamine formed from spermidine. It is found in a wide variety of organisms and tissues and is an essential growth factor in some bacteria. It is found as a polycation at all pH values. Spermine is associated with nucleic acids, particularly in viruses, and is thought to stabilize the helical structure.Chromatography, Ion Exchange: Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.Choline: A basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Organophosphorus Compounds: Organic compounds that contain phosphorus as an integral part of the molecule. Included under this heading is broad array of synthetic compounds that are used as PESTICIDES and DRUGS.Biophysical Phenomena: The physical characteristics and processes of biological systems.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Calcimycin: An ionophorous, polyether antibiotic from Streptomyces chartreusensis. It binds and transports CALCIUM and other divalent cations across membranes and uncouples oxidative phosphorylation while inhibiting ATPase of rat liver mitochondria. The substance is used mostly as a biochemical tool to study the role of divalent cations in various biological systems.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Calcium Channel Blockers: A class of drugs that act by selective inhibition of calcium influx through cellular membranes.Molecular Weight: The sum of the weight of all the atoms in a molecule.Lasalocid: Cationic ionophore antibiotic obtained from Streptomyces lasaliensis that, among other effects, dissociates the calcium fluxes in muscle fibers. It is used as a coccidiostat, especially in poultry.Tetraphenylborate: An anionic compound that is used as a reagent for determination of potassium, ammonium, rubidium, and cesium ions. It also uncouples oxidative phosphorylation and forms complexes with biological materials, and is used in biological assays.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Extracellular Space: Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.Receptors, Purinergic P2X7: A purinergic P2X neurotransmitter receptor that plays a role in pain sensation signaling and regulation of inflammatory processes.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Bentonite: A colloidal, hydrated aluminum silicate that swells 12 times its dry size when added to water.Sulfonic Acids: Inorganic or organic oxy acids of sulfur which contain the RSO2(OH) radical.Meglumine: 1-Deoxy-1-(methylamino)-D-glucitol. A derivative of sorbitol in which the hydroxyl group in position 1 is replaced by a methylamino group. Often used in conjunction with iodinated organic compounds as contrast medium.Aquilegia: A plant genus of the family RANUNCULACEAE that contains aquiledine, isoaquiledine and cycloartane-type glycosides.Magnetic Resonance Spectroscopy: 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).Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Sodium Isotopes: Stable sodium atoms that have the same atomic number as the element sodium, but differ in atomic weight. Na-23 is a stable sodium isotope.Membrane Transport Modulators: Agents that affect ION PUMPS; ION CHANNELS; ABC TRANSPORTERS; and other MEMBRANE TRANSPORT PROTEINS.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Potassium-Hydrogen Antiporters: Membrane proteins that allow the exchange of hydrogen ions for potassium ions across the cellular membrane. The action of these antiporters influences intracellular pH and potassium ion homeostasis.Ion Exchange Resins: High molecular weight, insoluble polymers which contain functional groups that are capable of undergoing exchange reactions (ION EXCHANGE) with either cations or anions.Buffers: A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.Xenopus: An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Nigericin: A polyether antibiotic which affects ion transport and ATPase activity in mitochondria. It is produced by Streptomyces hygroscopicus. (From Merck Index, 11th ed)Phosphates: Inorganic salts of phosphoric acid.Receptors, Purinergic P2: A class of cell surface receptors for PURINES that prefer ATP or ADP over ADENOSINE. P2 purinergic receptors are widespread in the periphery and in the central and peripheral nervous system.DNA: 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).Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Bromides: Salts of hydrobromic acid, HBr, with the bromine atom in the 1- oxidation state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Melibiose: A disaccharide consisting of one galactose and one glucose moiety in an alpha (1-6) glycosidic linkage.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Anemia, Hemolytic, Congenital: Hemolytic anemia due to various intrinsic defects of the erythrocyte.Free Radicals: 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.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Ruthenium Red: An inorganic dye used in microscopy for differential staining and as a diagnostic reagent. In research this compound is used to study changes in cytoplasmic concentrations of calcium. Ruthenium red inhibits calcium transport through membrane channels.Receptors, Purinergic P2X4: A widely distributed purinergic P2X receptor subtype that plays a role in pain sensation. P2X4 receptors found on MICROGLIA cells may also play a role in the mediation of allodynia-related NEUROPATHIC PAIN.Muscles: Contractile tissue that produces movement in animals.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Mercury: A silver metallic element that exists as a liquid at room temperature. It has the atomic symbol Hg (from hydrargyrum, liquid silver), atomic number 80, and atomic weight 200.59. Mercury is used in many industrial applications and its salts have been employed therapeutically as purgatives, antisyphilitics, disinfectants, and astringents. It can be absorbed through the skin and mucous membranes which leads to MERCURY POISONING. Because of its toxicity, the clinical use of mercury and mercurials is diminishing.Hydrogen: 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.Fura-2: A fluorescent calcium chelating agent which is used to study intracellular calcium in tissues.Bacterial Proteins: Proteins found in any species of bacterium.Acid Sensing Ion Channels: A family of proton-gated sodium channels that are primarily expressed in neuronal tissue. They are AMILORIDE-sensitive and are implicated in the signaling of a variety of neurological stimuli, most notably that of pain in response to acidic conditions.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Ion Pumps: A general class of integral membrane proteins that transport ions across a membrane against an electrochemical gradient.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Heptanes: Seven-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.Calcium Signaling: Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.Carnitine: A constituent of STRIATED MUSCLE and LIVER. It is an amino acid derivative and an essential cofactor for fatty acid metabolism.Membranes, Artificial: Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid: An inhibitor of anion conductance including band 3-mediated anion transport.Solutions: The homogeneous mixtures formed by the mixing of a solid, liquid, or gaseous substance (solute) with a liquid (the solvent), from which the dissolved substances can be recovered by physical processes. (From Grant & Hackh's Chemical Dictionary, 5th ed)Sodium Radioisotopes: Unstable isotopes of sodium that decay or disintegrate emitting radiation. Na atoms with atomic weights 20-22 and 24-26 are radioactive sodium isotopes.PolyaminesSodium-Hydrogen Antiporter: A plasma membrane exchange glycoprotein transporter that functions in intracellular pH regulation, cell volume regulation, and cellular response to many different hormones and mitogens.Silver: Silver. An element with the atomic symbol Ag, atomic number 47, and atomic weight 107.87. It is a soft metal that is used medically in surgical instruments, dental prostheses, and alloys. Long-continued use of silver salts can lead to a form of poisoning known as ARGYRIA.Fructokinases: A class of enzymes that catalyzes the phosphorylation of fructose in the presence of ATP. EC 2.7.1.-.Calixarenes: Phenolic metacyclophanes derived from condensation of PHENOLS and ALDEHYDES. The name derives from the vase-like molecular structures. A bracketed [n] indicates the number of aromatic rings.Spectrophotometry, Ultraviolet: 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)Thapsigargin: A sesquiterpene lactone found in roots of THAPSIA. It inhibits CA(2+)-TRANSPORTING ATPASE mediated uptake of CALCIUM into SARCOPLASMIC RETICULUM.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Electrolytes: Substances that dissociate into two or more ions, to some extent, in water. Solutions of electrolytes thus conduct an electric current and can be decomposed by it (ELECTROLYSIS). (Grant & Hackh's Chemical Dictionary, 5th ed)Receptors, Purinergic P2X: A subclass of purinergic P2 receptors that signal by means of a ligand-gated ion channel. They are comprised of three P2X subunits which can be identical (homotrimeric form) or dissimilar (heterotrimeric form).Data Collection: Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Molecular Conformation: The characteristic three-dimensional shape of a molecule.

The contribution of adjacent subunits to the active sites of D-3-phosphoglycerate dehydrogenase. (1/3963)

D-3-Phosphoglycerate dehydrogenase (PGDH) from Escherichia coli is allosterically inhibited by L-serine, the end product of its metabolic pathway. Previous results have shown that inhibition by serine has a large effect on Vmax and only a small or negligible effect on Km. PGDH is thus classified as a V-type allosteric enzyme. In this study, the active site of PGDH has been studied by site-directed mutagenesis to assess the role of certain residues in substrate binding and catalysis. These consist of a group of cationic residues (Arg-240, Arg-60, Arg-62, Lys-39, and Lys-141') that potentially form an electrostatic environment for the binding of the negatively charged substrate, as well as the only tryptophan residue found in PGDH and which fits into a hydrophobic pocket immediately adjacent to the active site histidine residue. Interestingly, Trp-139' and Lys-141' are part of the polypeptide chain of the subunit that is adjacent to the active site. The results of mutating these residues show that Arg-240, Arg-60, Arg-62, and Lys-141' play distinct roles in the binding of the substrate to the active site. Mutants of Trp-139' show that this residue may play a role in stabilizing the catalytic center of the enzyme. Furthermore, these mutants appear to have a significant effect on the cooperativity of serine inhibition and suggest a possible role for Trp-139' in the cooperative interactions between subunits.  (+info)

The stimulatory effects of Hofmeister ions on the activities of neuronal nitric-oxide synthase. Apparent substrate inhibition by l-arginine is overcome in the presence of protein-destabilizing agents. (2/3963)

A variety of monovalent anions and cations were effective in stimulating both calcium ion/calmodulin (Ca2+/CaM)-independent NADPH-cytochrome c reductase activity of, and Ca2+/CaM-dependent nitric oxide (NO.) synthesis by, neuronal nitric oxide synthase (nNOS). The efficacy of the ions in stimulating both activities could be correlated, in general, with their efficacy in precipitating or stabilizing certain proteins, an order referred to as the Hofmeister ion series. In the hemoglobin capture assay, used for measurement of NO. production, apparent substrate inhibition by L-arginine was almost completely reversed by the addition of sodium perchlorate (NaClO4), one of the more effective protein-destabilizing agents tested. Examination of this phenomenon by the assay of L-arginine conversion to L-citrulline revealed that the stimulatory effect of NaClO4 on the reaction was observed only in the presence of oxyhemoglobin or superoxide anion (generated by xanthine and xanthine oxidase), both scavengers of NO. Spectrophotometric examination of nNOS revealed that the addition of NaClO4 and a superoxide-generating system, but neither alone, prevented the increase of heme absorption at 436 nm, which has been attributed to the nitrosyl complex. The data are consistent with the release of autoinhibitory NO. coordinated to the prosthetic group of nNOS, which, in conjunction with an NO. scavenger, causes stimulation of the reaction.  (+info)

Screening for mutations of the cationic trypsinogen gene: are they of relevance in chronic alcoholic pancreatitis? (3/3963)

BACKGROUND: In hereditary pancreatitis mutations of exons 2 (N21I) and 3 (R117H) of the cationic trypsinogen gene have been described. AIMS: To investigate whether the same mutations can also be found in patients with chronic alcoholic pancreatitis. METHODS: Leucocyte DNA was prepared from 23 patients with chronic alcoholic pancreatitis, 21 with alcoholic liver cirrhosis, 34 individuals from seven independent families with hereditary pancreatitis, and 15 healthy controls. DNA was also obtained from pancreatic tissue (n=7) and from pancreatic juice (n=5) of patients suffering from chronic alcoholic pancreatitis. R117H was detected by restriction digestion with Afl III. N21I was identified by an allele specific polymerase chain reaction (PCR). RESULTS: R117H was detected in four families with hereditary pancreatitis. The N21I mutation was identified in three families. All mutations were confirmed by sequencing of the corresponding DNAs. In patients with chronic alcoholic pancreatitis neither the exon 2 nor exon 3 mutations were present in blood leucocytes, pancreatic juice, or pancreatic tissue. DNA of the patients with alcoholic liver cirrhosis as well as all controls was of wild type. CONCLUSIONS: The allele specific PCR may be used to screen for the N21I mutation of cationic trypsinogen. Both trypsinogen mutations were found in hereditary pancreatitis but do not seem to be major pathogenic factors in chronic alcoholic pancreatitis.  (+info)

Location of a cation-binding site in the loop between helices F and G of bacteriorhodopsin as studied by 13C NMR. (4/3963)

The high-affinity cation-binding sites of bacteriorhodopsin (bR) were examined by solid-state 13C NMR of samples labeled with [3-13C]Ala and [1-13C]Val. We found that the 13C NMR spectra of two kinds of blue membranes, deionized (pH 4) and acid blue at pH 1.2, were very similar and different from that of the native purple membrane. This suggested that when the surface pH is lowered, either by removal of cations or by lowering the bulk pH, substantial change is induced in the secondary structure of the protein. Partial replacement of the bound cations with Na+, Ca2+, or Mn2+ produced additional spectral changes in the 13C NMR spectra. The following conclusions were made. First, there are high-affinity cation-binding sites in both the extracellular and the cytoplasmic regions, presumably near the surface, and one of the preferred cation-binding sites is located at the loop between the helix F and G (F-G loop) near Ala196, consistent with the 3D structure of bR from x-ray diffraction and cryoelectron microscopy. Second, the bound cations undergo rather rapid exchange (with a lifetime shorter than 3 ms) among various types of cation-binding sites. As expected from the location of one of the binding sites, cation binding induced conformational alteration of the F-G interhelical loop.  (+info)

Modulation of slow inactivation in human cardiac Kv1.5 channels by extra- and intracellular permeant cations. (5/3963)

1. The properties and regulation of slow inactivation by intracellular and extracellular cations in the human heart K+ channel hKv1.5 have been investigated. Extensive NH2- and COOH-terminal deletions outside the central core of transmembrane domains did not affect the degree of inactivation. 2. The voltage dependence of steady-state inactivation curves of hKv1.5 channels was unchanged in Rb+ and Cs+, compared with K+, but biexponential inactivation over 10 s was reduced from approximately 100 % of peak current in Na+ to approximately 65 % in K+, approximately 50 % in Rb+ and approximately 30 % in Cs+. This occurred as a result of a decrease in both fast and slow components of inactivation, with little change in inactivation time constants. 3. Changes in extracellular cation species and concentration (5-300 mM) had only small effects on the rates of inactivation and recovery from inactivation (tau recovery approximately 1 s). Mutation of residues at a putative regulatory site at R487 in the outer pore mouth did not affect slow inactivation or recovery from inactivation of hKv1.5, although sensitivity to extracellular TEA was conferred. 4. Symmetrical reduction of both intra- and extracellular cation concentrations accelerated and augmented both components of inactivation of K+ (Kd = 34.7 mM) and Cs+ (Kd = 20.5 mM) currents. These effects could be quantitatively accounted for by unilateral reduction of intracellular K+ (K+i) (Kd = 43.4 mM) or Cs+i with constant 135 mM external ion concentrations. 5. We conclude that inactivation and recovery from inactivation in hKv1.5 were not typically C-type in nature. However, the ion species dependence of inactivation was still closely coupled to ion permeation through the pore. Intracellular ion modulatory actions were more potent than extracellular actions, although still of relatively low affinity. These results suggest the presence of ion binding sites capable of regulating inactivation located on both intracellular and extracellular sides of the pore selectivity filter.  (+info)

Gating current studies reveal both intra- and extracellular cation modulation of K+ channel deactivation. (6/3963)

1. The presence of permeant ions can modulate the rate of gating charge return in wild-type human heart K+ (hKv1.5) channels. Here we employ gating current measurements in a non-conducting mutant, W472F, of the hKv1.5 channel to investigate how different cations can modulate charge return and whether the actions can be specifically localized at the internal as well as the external mouth of the channel pore. 2. Intracellular cations were effective at accelerating charge return in the sequence Cs+ > Rb+ > K+ > Na+ > NMG+. Extracellular cations accelerated charge return with the selectivity sequence Cs+ > Rb+ > Na+ = NMG+. 3. Intracellular and extracellular cation actions were of relatively low affinity. The Kd for preventing slowing of the time constant of the off-gating current decay (tau off) was 20.2 mM for intracellular Cs+ (Cs+i) and 358 mM for extracellular Cs+ (Cs+o). 4. Both intracellular and extracellular cations can regulate the rate of charge return during deactivation of hKv1.5, but intracellular cations are more effective. We suggest that ion crystal radius is an important determinant of this action, with larger ions preventing slowing more effectively. Important parallels exist with cation-dependent modulation of slow inactivation of ionic currents in this channel. However, further experiments are required to understand the exact relationship between acceleration of charge return and the slowing of inactivation of ionic currents by cations.  (+info)

Phospholipid-subclass-specific partitioning of lipophilic ions in membrane-water systems. (7/3963)

Herein, we systematically investigate phospholipid-subclass-specific alterations in the partitioning of both cationic and anionic amphiphiles to identify the importance of ester, ether and vinyl ether linkages at the sn-1 position of phospholipids in the partitioning of charged amphiphiles. The results demonstrated that the membrane-water partition coefficient of a prototypic cationic amphiphile (i.e. 3,3'-dipropylthiadicarbocyanine iodide) was approximately 2.5 times higher in membranes comprised of plasmenylcholine in comparison with membranes comprised of either phosphatidylcholine or plasmanylcholine. In striking contrast, the membrane-water partition coefficient of a prototypic anionic amphiphile [i.e. bis-(1,3-dibutylbarbituric acid)trimethine oxonol] in membranes comprised of plasmenylcholine was approximately 2.5 times lower than that manifest in membranes comprised of phosphatidylcholine or plasmanylcholine. Utilizing theseexperimentally determined partition coefficients,the relative membrane dipole potential of membranes comprised of plasmenylcholine was calculated and found to be approximately 25 mV lower than in membranes comprised of phosphatidylcholine or plasmanylcholine. This lower membrane dipole potential in membranes comprised of plasmenylcholine is equivalent to the membrane potential induced by incorporation of approximately 25 mol% of anionic phospholipids in membranes comprised of phosphatidylcholine. Collectively, these results demonstrate that phospholipid-subclass-specific differences in the membrane dipole potential contribute to alterations in the partitioning of lipophilic ions in membrane bilayers comprised of distinct phospholipid subclasses. Moreover, they suggest that these physicochemical differences can be exploited to facilitate the targeting of charged lipophilic drugs to specific cells and subcellular membrane compartments.  (+info)

Partitioning of triphenylalkylphosphonium homologues in gel bead-immobilized liposomes: chromatographic measurement of their membrane partition coefficients. (8/3963)

Unilamellar liposomes of small or large size, SUVs and LUVs, respectively, were stably immobilized in the highly hydrophilic Sepharose 4B or Sephacryl S-1000 gel beads as a membrane stationary phase for immobilized liposome chromatography (ILC). Lipophilic cations of triphenylmethylphosphonium and tetraphenylphosphonium (TPP+) have been used as probes of the membrane potential of cells. Interaction of TPP+ and triphenylalkylphosphonium homologues with the immobilized liposomal membranes was shown by their elution profiles on both zonal and frontal ILC. Retardation of the lipophilic cations on the liposome gel bed was increased as the hydrophobicity of the cations increased, indicating the partitioning of lipophilic cations into the hydrocarbon region of the membranes. The cations did not retard on the Sepharose or Sephacryl gel bed without liposomes, confirming that the cations only interact with the immobilized liposomes. Effects of the solute concentration, flow rate, and gel-matrix substance on the ILC were studied. The stationary phase volume of the liposomal membranes was calculated from the volume of a phospholipid molecule and the amount of the immobilized phospholipid, which allowed us to determine the membrane partition coefficient (KLM) for the lipophilic cations distributed between the aqueous mobile and membrane stationary phases. The values of KLM were generally increased with the hydrophobicity of the solutes increased, and were higher for the SUVs than for the LUVs. The ILC method described here can be applied to measure membrane partition coefficients for other lipophilic solutes (e.g., drugs).  (+info)

Cation-π interaction is a non-covalent binding force that plays a significant role in protein stability and drug-receptor interactions. In this work, we have investigated the structural role of cation-π interactions in sugar-binding proteins (SBPs). We observed 212 cation-π interactions in 53 proteins out of 59 SBPs in dataset. There is an average one energetically significant cation-π interaction for every 66 residues in SBPs. In addition, Arg is highly preferred to form cation-π interactions, and the average energy of Arg-Trp is high among six pairs. Long-range interactions are predominant in the analyzed cation-π interactions. Comparatively, all interaction pairs favor to accommodate in strand conformations. The analysis of solvent accessible area indicates that most of the aromatic residues are found on buried or partially buried whereas cationic residues were found mostly on the exposed regions of protein. The cation-π interactions forming residues were found that around 43% of cation-π
Engineering of mixed-valence (MV) radical cations and intermolecular complexes based on pi-extended tetrathiafulvalenes (TTFs) is central for the development of organic conductors. On another front, redox-controlled dimerization of radical cations has recently been recognized as an important tool in supramolecular chemistry. Here we show that pi-extended TTFs based on the indenofluorene core, prepared by Horner-Wadsworth-Emmons reactions, undergo reversible and stepwise one-electron oxidations and that the detectable, intermediate radical cation forms remarkably strong intermolecular MV ([neutral.cation]) and pi-dimer ([cation.cation]) complexes with near-infrared radical cation absorptions. The radical cation itself seems to be a so-called Class III MV species in the Robin-Day classification. The formation of MV dimers was corroborated by ESR spectroelectrochemical studies, revealing two slightly different ESR signals upon oxidation, one assigned to the MV dimer and the other to the cation monomer.
Over the last several years, various gene delivery systems have been developed for gene therapy applications. Although viral vector-based gene therapy has led
The visible light combined with photosensitizers (PSs) is exploited in both antitumoral and antimicrobial fields inducing a photo-oxidative stress within the target cells. Among the different PSs, porphyrins belong to the family of the most promising compounds to be used in clinical photodynamic applications. Although in the last years many porphyrins have been synthesised and tested, only a few reports concern the in vitro effects of the 5,15-diarylporphyrins. In this work, the activity of four 5,15-diarylporphyrins (compounds 7-10), bearing alkoxy-linked pyridinium appendixes, have been tested on cancer cell lines and against bacterial cultures. Among the synthetized PSs, compounds 7 and 9 are not symmetrically substituted porphyrins showing one cationic charge tethered at the end of one 4C or 8C carbon chains, respectively. On the other hand, compounds 8 and 10 are symmetrically substituted and show two chains of C4 and C8 carbons featuring a cationic charge at the end of both chains. The ...
Müller, A., Krickemeyer, E., Bögge, H., Schmidtmann, M., Botar, B., & Talismanova, M. O. (2003). Drawing small cations into highly charged porous nanocontainers reveals "Water" assembly and related interaction problems. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 42(18), 2085-2090. doi:10.1002/anie. ...
RESULTS: Viscometry first showed that these polymers display typical polysoap behaviour in hydro‐alcoholic mixtures. Fluorescence spectrometry was then used to characterize the corresponding intramolecular association with two complementary fluorescent probes. In addition to confirming macromolecular folding, pyrene provided information about the probe local environment polarity whereas a molecular rotor gave interesting complementary information about the compactness of the corresponding nano‐domains ...
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Synonyms for Cations, divalent in Free Thesaurus. Antonyms for Cations, divalent. 1 synonym for divalent: bivalent. What are synonyms for Cations, divalent?
View Notes - 0243Pb45anp2-09 from CHEM orgo at NYU. + + Both cations (these are NOT resonance forms - they are two separate cations) are captured - two steps please - to give the two final products.
Summary: This chapter focuses on changeover metals. All transition metal cations are toxic-the ones that are essential for Escherichia coli and belong to the main get redirected here transition period of the periodic program with the element and also the toxic-only metals with increased atomic figures. Prevalent themes are noticeable inside the metabolism of those ions. To start with, there is transport. Superior-price but minimal-affinity uptake techniques offer many different cations and anions on the cells. Charge of the respective systems is apparently mainly via regulation of transport action (flux Management), with Charge of gene expression enjoying just a slight role. If these units never deliver adequate amounts of a desired ion into the mobile, genes for ATP-hydrolyzing superior-affinity but very low-fee uptake techniques are induced, e.g., ABC transport methods or P-kind ATPases. However, if the level of an ion is in surplus, genes for efflux methods are induced. from this source By ...
1AEE: Artificial protein cavities as specific ligand-binding templates: characterization of an engineered heterocyclic cation-binding site that preserves the evolved specificity of the parent protein.
1AEG: Artificial protein cavities as specific ligand-binding templates: characterization of an engineered heterocyclic cation-binding site that preserves the evolved specificity of the parent protein.
Structural Diversity and Thermochromic Properties of Iodobismuthate Materials Containing d-Metal Coordination Cations: Observation of a High Symmetry [Bi3I11]2− Anion and of Isolated I− Anions
Buy our Recombinant Human M6PR (cation dependent) protein. Ab80157 is a protein fragment produced in Escherichia coli and has been validated in WB, ELISA…
Gentaur molecular products has all kinds of products like :search , Trevigen \ DPO_4+ Buffer + Cations \ 4150-010-EB for more molecular products just contact us
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Article: Teamwork allows people to discuss their work together, and as a result, to grow professionally. To be successful, the teacher and para-educator must view themselves as a team and partners in the educational process ...
1776. Somme des cations échangeables (S) : Somme des cations métalliques échangeables exprimée en milliéquivalents-grammes pour 100 grammes de complexe absorbant ...
TY - JOUR. T1 - Cationic lipid-mediated NGF gene transfection increases neurofilament phosphorylation. AU - Yang, K.. AU - Xue, J. J.. AU - Qiu, Y. H.. AU - Perez-Polo, J. R.. AU - Whitson, J.. AU - Faustinella, F.. AU - Kampfl, A.. AU - Zhao, X.. AU - Iwamoto, Y.. AU - Mu, X. S.. AU - Clifton, G.. AU - Hayes, R. L.. PY - 1996/12/31. Y1 - 1996/12/31. N2 - We examined the effect of cationic lipid-mediated gene transfection of nerve growth factor (NGF) in primary septo-hippocampal cell cultures. Rat NGF cDNA was subcloned into a pUC19-based plasmid containing a CMV promoter. Two days after NGF gene transfection in primary cell cultures, ELISA confirmed increases in NGF protein secretion from transfected cells. To study the biological effect of cationic lipid-mediated NGF gene transfection, we analyzed the amount of neurofilament protein from NGF-transfected cell cultures. Western blot and immunohistochemical analyses detected significant increases in the phosphorylated form of neurofilament ...
The dyes were first introduced by Hoechst, based on ß-sulphato ethyl sulphone as a reactive group. The range made the successful breakthrough due to comprehensive shade range, versatile application, ability to be dyed at 60°C and good compatibility with other bifunctional dyes. Being a compact structure, it offers ease in wash off for removal of unfixed dyes at the end of dyeing during washing. The dye fibre bond offers good acid stability. With the limitations to above, there may be problems with reproducibility associated with it, which is not accepted especially for pale shades. There is the possibility of unlevel dyeing with a small variation in the process due to its lower molecular weight. Hetero bifunctional dyes made a get through in early 80s. The dyes were based on a quite simple but beautiful chemistry. They had filled a big vacuum of various hues of bright shades, which were not possible with vinyl sulphone type. The dyes were conventional dichlorotriazine type, with the end ...
(CYANOMETHYL)TRIPHENYLPHOSPHONIUM CHLORIDE 4336-70-3 NMR spectrum, (CYANOMETHYL)TRIPHENYLPHOSPHONIUM CHLORIDE H-NMR spectral analysis, (CYANOMETHYL)TRIPHENYLPHOSPHONIUM CHLORIDE C-NMR spectral analysis ect.
The barrier for the radical isomerization CH3Oo --, oCH2OH is calculated by CBS-QB3 to be 29.7 kcal mol-1 and lies higher (by 5.7 kcal mol-1) than the dissociation limit CH2O+Ho. Hence, CH3Oo does not isomerize to the more stable oCH2OH on its own. However, this barrier is reduced to 15.8 ... read more kcal mol-1 when the CH3Oo radical is coordinated with protonated methanol (CH3-Oo...H-O(H)-CH3+) and the CH3Oo --,oCH2OH rearrangement can now take place within the complex. This rearrangement, which results in the hydrogen-bridged radical cation oCH2-O(H)...H-O(H)-CH3+ can be viewed as an acid catalyzed rearrangement. The ion CH3-Oo...H-O(H)-CH3+ represents the most stable form of the methanol dimer radical cation. The ion oCH2-O(H)...H-O(H)-CH3+ can fragment directly to CH3OH2+ + oCH2OH or it can rearrange further to produce the hydrogen-bridged radical cation oCH2-O+(CH3)-H...OH2, which is the dimethylether ylid cation solvated by water. This species can dissociate to its components or tho ...
Antimicrobial peptides (AMPs) are a class of antimicrobial agents with broad-spectrum activities. Several reports indicate that cationic AMPs bind to the negatively charged bacterial membrane causing membrane depolarization and damage. However, membrane depolarization and damage may be insufficient to elicit cell death, thereby suggesting that other mechanism(s) of action could be involved in this phenomenon. In this study, we investigated the antimicrobial activity of a novel antimicrobial peptide, TP359, against two strains of Pseudomonas aeruginosa, as well as its possible mechanisms of action. TP359 proved to be bactericidal against P. aeruginosa as confirmed by the reduced bacteria counts, membrane damage and cytoplasmic membrane depolarization. In addition, it was non-toxic to mouse J774 macrophages and human lung A549 epithelial cells. Electron microscopy analysis showed TP359 bactericidal effects by structural changes of the bacteria from viable rod-shaped cells to those with cell membrane
A promising strategy to improve the immunogenic potential of DNA vaccines is the formulation of plasmid DNA (pDNA) with cationic liposomes. In this respect, particle size may be of crucial importance. This study aimed at the evaluation of high-pressure extrusion as a method for sizing cationic liposomes after entrapment of pDNA. This is a well-known sizing method for liposomes, but so far, it has not been applied for liposomes that are already loaded with pDNA. Liposomes composed of egg PC, DOTAP, and DOPE with entrapped pDNA were prepared by the dehydration-rehydration method and subjected to various extrusion cycles, comparing different membrane pore sizes and extrusion frequencies. At optimized extrusion conditions, liposome diameter (Zave) and polydispersity index (PDI) were reduced from 560 nm and 0.56 to 150 nm and 0.14 respectively, and 35% of the pDNA was retained. Importantly, gel electrophoresis and transfection experiments with pDNA extracted from these extruded liposomes demonstrated ...
Semple, SC, Akinc, A, Sandhu, A, Mui, B, Chow, C, Sah, D, Stebbing, D, Crosley, E, Hafez, I, Dorkin, JR, Qin, J, Lam, K, Wong, K, Nechev, L, Eisenhardt, ML, Jayaraman, M, Kazem, M, Maier, M, Srinivasulu, M, Weinstein, M, Chen, Q, Alvarez, R, Barros, S, Klimuk, SK, Borland, T, Kosovrasti, V, Tam, Y, MacLachlan, I, Manoharan, M, Ciufolini, MA, Tracy, M, de Fougerolles, A, Cullis, PR, Madden, TD, Hope, ...
Experimental and Theoretical Examination of the Radical Cations Obtained from the Chemical and Electrochemical Oxidation of 5-AminothiazolesExperimental and Theoretical Examination of the Radical Cations Obtained from the Chemical and Electrochemical Oxidation of 5-Aminothiazoles ...
Non-stop carbocationic polycyclizations of isoprenoids have been called the most complex chemical reactions occurring in nature. We describe a strategy for the initiation of tail-to-head polycyclization that relies on the sequestration of the counteranion away from the carbocation, which allows full propagation of the cationic charge. If the anion is mobile, Coulombic forces hold this species in close proximity to the carbocation and cause preemptive termination through elimination. Anion sequestration is crucial for effecting the biomimetic synthesis of complex and unstable terpenes, including the highly strained funebrenes. This study illustrates the deleterious role of the counterion in tail-to-head carbocationic polycyclization reactions, which to the best of our knowledge has not been rigorously explored. These observations are also expected to find use in the design and control of cationic polycyclization along biosynthetic pathways that have previously been inaccessible in bulk solvent ...
TY - JOUR. T1 - The dithiacyclooctane cation (DTCO+). T2 - Conformational analysis, interconversion barriers and bonding. AU - Stowasser, Ralf. AU - Glass, Richard S. AU - Hoffmann, Roald. PY - 1999/7. Y1 - 1999/7. N2 - A theoretical conformation analysis of the dithiacyclooctane radical cation (DTCO+) suggests that the lowest energy conformer is a chair-boat, with a partial but significant S-S σ bond. For the ring flip process of this molecule we calculate a barrier of 40 kJ mol-1 and two possible pathways: one involves a boat-boat conformer and an untwisted transition structure, the other a chair-chair conformer and a twisted transition structure.. AB - A theoretical conformation analysis of the dithiacyclooctane radical cation (DTCO+) suggests that the lowest energy conformer is a chair-boat, with a partial but significant S-S σ bond. For the ring flip process of this molecule we calculate a barrier of 40 kJ mol-1 and two possible pathways: one involves a boat-boat conformer and an ...
Histochemical and morphological research increasingly relies upon quanti cation of complex biological systems. For such investigations to be meaningful, quanti cation techniques must meet the seemingly conflicting requirements of being theoretically robust, yet sufficiently practical to facilitate widespread applicability. Validity ought to be enhanced by theoretical simplicity, use of measured rather than assumed variables, and minimising observer interpretation. Practicality is facilitated by simplifying and reducing measurements, broadening applicability, and reducing costs and analysis time. As a result, quanti cation systems that rely upon sampling and estimation have been favoured over serial reconstruction techniques. To provide reliable estimates, sampling must be valid at all levels from tissue harvest, to the selection of microscope fields in which quanti cation is performed by techniques that account for the anisotropic distribution, and variable size of many elements in biological ...
Positively charged cations and negatively charged anions attract one another. Conversely, cations repel one another as do anions.. Electrostatic attraction is indiscriminate. That is a cation can attract more than one anion and visa versa. The result is that cation-anions attractions form a large array that we call an ionic compound or salt. The bonds holding these ions together are called ionic bonds. However, this array has a very specific composition completely dictated by the charges on the cations and anions.. Formulas of ionic compounds:. The composition of ionic compounds is determined by the requirement that the compounds must be electrically neutral. That is that the charges of the cations and anions must balance or cancel out one another. For example consider sodium cations (Na+) and Chlorine anions (Cl ). Sodium has a positive 1 charge and chloride has a negative 1 charge. Thus one sodium cation cancels one chloride anion (+1 + 1 = 0) resulting in the formula Na1Cl1 or NaCl. ...
We present a detailed analysis of the anomalous carbocations: C2H5+ and C3H3+. This work involves (a) probing electronic structural properties, (b) ab initio dynamics simulations over a range of internal energies, (c) analysis of reduced dimensional potential surfaces directed along selected conformational t
View Notes - Lecture21outline from CHEM 0740 at Pittsburgh. I. Review Nucleophiles generally add to anomeric carbocations from the axial face This is a result of the anomeric effect that states that
Compartment GO Term. serotonin-activated cation-selective channel complex onclick="removeFacet(Compartment GO Term/serotonin-activated cation-selective channel complex)"> Compartment GO Term serotonin-activated cation-selective channel complex ...
Page contains details about cationic liposomes 9:1 . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Radical cations and dications of [n]CPP from n = 5 to n = 12 have been studied by Raman spectroscopy and density functional theory. Small [n]CPP dications owe their stability to the closed-shell electronic structure imposed by cyclic conjugation surpassing the destabilizing effect of ring strain and of the e
Used for cation analysis by Ion Chromatography, these standards for cation analysis can be used for primary calibration or to prepare second source calibration check standards.
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...and I dont have the photo to prove it! Does a meet up really happen if theres no photographic evidence? Last Thursday Cation Designs, Morgan of Crab & Bee, Meris of The Fabric Alchemist, and I met up for brunch at Lola in downtown Seattle. Cation Designs was in town for a few days, and her visit was the…
Buryi, VA ; Morel, Nicole ; Godfraind, Theophile. Model of cation channel gating.In: Progress in Biophysics & Molecular Biology, Vol. 65, p. PC330-PC330 (1996 ...
During the study of the radical induced DNA strand cleavage, we observed the appearance of a radical cation at the carbohydrate backbone.1 This radical cation is a strong oxidant that can be reduced by an adjacent guanosine (G).2 The so formed guanine
An atom with more protons than electrons, giving it a net positive charge. For example, a sodium atom becomes a cation when it transfers an electron to a chlorine atom to form sodium chloride. See also Ion and Anion.. ...
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Waters offers an array of products for ion chromatography . IC-Pak resin based columns allow you to analyze a full range of ions from numerous sample matrices, both simple and complex. They offer an exceptional linear loading range of less than 1.0 ppb to greater than 400 ppm without dilution and without pH limitation on eluent or sample. The flexibility exists for accurate and reproducible anion and cation analyses at all concentration levels.
Wolf, R., Dommröse, A. - M., & Grützmacher, H. - F. (1988). Destabilized carbenium ions: secondary and tertiary [alpha]-carbomethoxybenzyl cations. Organic Mass Spectrometry, 23(1), 26-32. doi:10.1002/oms. ...
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Maximum efficiency of cation hydrolysis will be shown by? a) \(\sf Al^{+3}\) b) \(\sf Tl^{+3}\) c) \(\sf Tl^{+1}\) d) \(\sf Ga^{+3}\)The answer i...
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Read independent reviews on Thermo Scientific™ CR-CTC II Continuously-Regenerated Cation Trap Column II from Thermo Fisher Scientific on SelectScience
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Cations are positively charged ions and anions are negatively charged ions. Metals act as cations and willingly give up or donate electrons to nonmetals. Nonmetals act as anions and accept donated...
A hydride shift is a rearrangement of atoms in which an unstable carbocation is transformed into a more stable one. Carbocations are ions with positively charged carbon atoms and are often found in...
well im studied C3 further science, and these have really got to me? not a clue what they are on about on the revision booklet i have, or on any of the revision notes i have come across on here? i dont know what are example and what i need to remember for my exam? any help?. ...
வேதியியலில் உப்பு (salt) என்பது ஒரு காடியும், காரமும் சேர்ந்து வேதியியல் வினைப்படும் பொழுது நடுமை அடைகையில் உருவாகும் பொருள். உப்புகள் மின்ம முனைப்படும் சேர்மங்கள் ஆகும். உப்புகளில் நேர்மின்மம் கொண்ட நேர்முனையி அல்லது கேட்டயான் (cation) பகுதியும், எதிர்மின்மம் கொண்ட எதிர்முனையி அல்லது ஆனையான் (anion) பகுதியும் கொண்ட ஆனால் மொத்தமாக மின்மம் ஏதுமற்ற, மின்மநடுநிலை கொண்ட ஒரு பொருள். ...
Hints: Click on a [map] link to show a map of that region. Click on a [studies] link to search within your current results for studies in that region. Use the back button to return to this list and try another region. Studies with no locations are not included in the counts or on the map. Studies with multiple locations are included in each region containing locations ...
This is a beautiful falls. I wish you could hear the roar of it. It is so magnificent! And see that black streak at the bottom left side of the falls...thats a salmon jumping up the falls! We watched several of them try but never made it. ...
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Divalent cation (Mg2+, Co2+ and Ni2+) transport system, CorA. Helical tilting and rotation in TM1 generates an iris-like motion that increases the diameter of the permeation pathway, triggering ion conduction, thus defining the gating mechanism (Dalmas et al. 2014 ...
The cation M2+ reacts with NH3 to form a series of complex ions as follows: M2+ + NH3 M(NH3)2+ K1 = 102 M(NH3)2+ + NH3 M(NH3)2 2+ K2 = 103 M(NH3)2 2+ + NH3 M(NH3)3 2+ K3 = 102 A 1.0 × 10-3 mol sample of M(NO3)2 is added to 1.0 L ...
Moore P B , Sen Gupta P K , Shen J , Schlemper E O , American Mineralogist , 76 (1991) p.1389-1399, The kentrolite-melanotekite series, 4Pb2(Mn,Fe)2O2[Si2O7]: Chemical, crystallographic relations, lone-pair splitting, and cation relation to 8URe2 ...
Novel cationic amphiphiles are provided that facilitate transport of biologically active (therapeutic) molecules into cells. The amphiphiles contain lipophilic groups derived from steroids, from mono or dialkylamines, or from alkyl or acyl groups; and cationic groups, protonatable at physiological pH, derived from amines, alkylamines or polyalkylamines. There are provided also therapeutic compositions prepared typically by contacting a dispersion of one or more cationic amphiphiles with the therapeutic molecules. Therapeutic molecules that can be delivered into cells according to the practice of the invention include DNA, RNA, and polypeptides. Representative uses of the therapeutic compositions of the invention include providing gene therapy, and delivery of antisense polynucleotides or biologically active polypeptides to cells. With respect to therapeutic compositions for gene therapy, the DNA is provided typically in the form of a plasmid for complexing with the cationic amphiphile. Novel and highly
Cation exchange capacity (CEC) and total exchangeable cations (TEC) are two significant concepts in soil fertility. Cations refer to the positively charged nutrients in the soil, e.g. Ca2+ and K+. They are important as they give you an idea of how many cations a soil can potentially hold and how many cations are currently being held. Understanding exactly how these soil properties influence soil fertility and applying soil management systems that enhance these properties can assist in improving pasture quality and yield.. CEC is defined as the degree to which a soil can adsorb (hold/capture) and exchange cations with the soil solution1. This term is often confused with a soils TEC which refers to the number of basic cations that are held on the soil exchange sites (CEC sites) in comparison to the total sites and is usually reported in cmol(+)/kg soil. The ability of the soil to hold nutrients is greatly influenced by the soils organic matter (OM) content, which is mostly made up of carbon, as ...
In the first group of cations, we include Silver(I), Mercury(I)and Lead(II) cations. Before we begin, it is good to note that mercury(I) ions - or mercurous ions - are NOT Hg+ but Hg22+.. The group reagent is dilute Hydrochloric acid.. When we pass dil. Hcl through the solution, we expect the precipitation of the chlorides of the aforementioned cations. ANY Precipitation is nothing but a chloride and the cation of the ppt. can not be any other than the three.. If a ppt is obtained, group I cations are confirmed. If not, we wll test the solution for the presence of group II cations.. Suppose we obtain a ppt on adding dil. HCl to the solution. It is inferred that the cation in the solution is either Ag+, Hg22+ or Pb2+.. Our goal now would be to distinguish between these three cations.. Before we pass onto this section, please realize that dil. HCl was added to only a part of the solution, taken in another testtube. The rest of the solution would be preserved for use in other tsts should it be ...
An apparatus for removing deposits from a razor blade includes a quantity of cation source material, a vessel retaining a cation carrying medium, and a medium and cation permeable barrier dividing the vessel and the medium into a blade placement region and a material retaining region, for separating the quantity of cation source material from the razor blade. The cation source material preferably includes several plastic beads. The medium permeable barrier is preferably a wire mesh. The cation carrying medium preferably includes water. A method of removing deposits from a razor blade includes the steps of: providing an apparatus including a vessel containing a water medium and cation source material at least partly submerged in the water medium, and immersing the blade in the water medium for a length of time to permit cations supplied by the material to react with the deposits on the blade.
Crystal structures of the Ti(III) tweezer complexes [(C,sub,5,/sub,HMe,sub,4,/sub,),sub,2,/sub,Ti(σ-C≡CSiMe,sub,3,/sub,),sub,2,/sub,],sup,-,/sup,[Li(THF),sub,2,/sub,],sup,+,/sup, (,strong,2a,/strong,), [(C,sub,5,/sub,HMe,sub,4,/sub,),sub,2,/sub,Ti(σ-C≡CSiMe,sub,3,/sub,),sub,2,/sub,],sup,-,/sup,Na,sup,+ ,/sup,(,strong,3,/strong,) and [(C,sub,5,/sub,HMe,sub,4,/sub,),sub,2,/sub,Ti(σ-C≡CSiMe,sub,3,/sub,),sub,2,/sub,],sup,-,/sup,Cs,sup,+,/sup, (,strong,5,/strong,) have been determined. In all of them the alkali metal cation is placed away from the Ti-C,sub,α1,/sub,-C,sub,α2,/sub, plane at the distance: Li,sup,+,/sup, 0.511 Å, Na,sup,+,/sup, 1.023 Å and Cs,sup,+,/sup, 0.521 Å. The reason for the deviation of Li,sup,+,/sup, in ,strong,2a,/strong, is the asymmetrical orientation of the THF ligands in the [Li(THF),sub,2,/sub,],sup,+,/sup, cation with respect to the Ti-C,sub,α1,/sub,-C,sub,α2,/sub, plane, which seems to release the steric congestion between the THF ligands and the ...
Read "DNA-Induced Aggregation and Fusion of Phosphatidylcholine Liposomes in the Presence of Multivalent Cations Observed by the Cryo-TEM Technique, The Journal of Membrane Biology" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
A retention model is derived for inorganic cations eluted from cation-exchange columns with eluents containing a single competing cation and a complexing ligand. This model is evaluated using divalent solute cations and a low-capacity fixed-site cation-exchange column, and good agreement is obtained between theoretical and experimental results both for simple cation exchange and also when complexation effects are present. Sodium ions added to the eluent during pH adjustment were found to contribute significantly to the elution of solute cations and should be included in all calculations using the retention model. Retention characteristics were also studied for an ion-interaction chromatographic system using a C18 column, octanesulfonic acid as the ion-interaction reagent, and oxalate as the complexing ligand in the eluent. Experimental data for this system did not show close agreement with the ion-exchange retention model. Discrepancies are attributed to variations in the ion-exchange capacity ...
The ever increasing advances in the integrated circuit technology made it possible for electronic system designers to assemble complete systems-on-chips (SoC). As these SoCs have been used in computer, graphics, and networking hardware systems, the complexity of functionality within them have rapidly increased. At the same time shrinking time to market leaves little room for errors in the design. Hence functional veri cation has become one of the major tasks in committing chips to fabrication. Just as designs are pushing towards reusable environment so must the veri cation environment. As veri cation itself takes 70% of the design time, the need of standalone, pre-veri ed veri ca- tion infrastructure is arisen so that veri cation does not become the bottleneck for the designers. The Veri cation Intellectual Property (Veri cation IP/VIP) which can be easily plugged in the simulation-based tests, is an important component of such infrastructure. In this dissertation the modeling of VIP of STBUS ...
Data files: ion polarisabilities, surface charge and potential (Fig.4), interaction energies (Fig.5) from Cation effects on haemoglobin aggregation: balance of chemisorption against physisorption of ions
Terpenoid synthases produce a plethora of polycyclic natural products from only a few acyclic precursors. The mechanisms of these impressive enzyme-catalyzed polycyclization reactions have been discussed for decades, but a key unsanswered question is whether or not nonclassical carbocations - carbocations that contain delocalized 3-center 2-electron bonding arrays - are involved in these mechanisms. Nonclassical carbocations are common in nonpolar environments and have even been shown to persist in aqueous solution. It is reasonable, therefore, to think that they may also persist in enzyme active sites. In order to assess the stability of nonclassical carbocations in terpenoid synthase active sites, we are examining complexes of nonclassical species with small models of various protein residues - so-called theozymes. Some of the types of enzyme-nonclassical cation interactions that are possible are shown schematically above. We have so far shown that complexes between active site residues and ...
Ab initio calculations, using restricted Hartree-Fock, density-functional (DFT) and Moeller-Plesset perturbation theories, have been performed to study the cation-pi interactions between alkali cations and [7]-helicene as well as the interaction between [7]-helicene and benzene. The helical molecules two terminal benzene rings give the profile of crocodiles jaws which open up to receive the cations, exhibiting the stability of the complexes increasing in the order Na+, K+, Cs+. The binding energies in these cation-pi complexes comprise mainly electrostatic, polarization (including dispersion) and charge transfer contributions. According to DFT, the electrostatic contribution alone is 43% for Na+, 60% for K+ and 75% for Cs+. However, even DFT shows very little stabilization for the helicene-benzene complex so that this interaction between a helical and a neutral molecule cannot serve as a model for DNA-drug interactions due to very little overlap between the pi clouds of the two ...
definition of CIM6PR, what does CIM6PR mean?, meaning of CIM6PR, Cation-Independent Mannose 6-Phosphate Receptor, CIM6PR stands for Cation-Independent Mannose 6-Phosphate Receptor
Thank you for your interest in spreading the word about Biochemical Society Transactions.. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.. ...
Cation distributions (CDs) in the representative collection of trans-vacant dioctahedral celadonites, glauconites and ferriillites were investigated using Mössbauer and IR spectroscopies and the original approach. The approach is based on individual quadrupole splittings Δipred for Fe3+ in possible local cation arrangements around Fe3+, and on a computer simulation of two-dimentional CDs using the IR data in the OH stretching vibration region.. The resulting CDs were next used to make correlations between Δj of Fe2+ derived from computer fits to the corresponding spectra and cation composition of local cation arrangements around Fe2+ with their occurrence probabilities. Basing on this correlations, a total of eight individual Δtent for Fe2+ referred as "tentative" have been derived.. The order of local cation arrangements in terms of increasing quadrupole splitting was found to be the same both for Fe3+ and Fe2+ and implies a direct dependence of the Fe2+ quadrupole splitting on the ...
TY - JOUR. T1 - Inhibition of ligand-gated cation-selective channels by tamoxifen. AU - Allen, Marcus. AU - Newland, Claire. AU - Valverde, Miguel A.. AU - Hardy, Simon. PY - 1998/9/16. Y1 - 1998/9/16. U2 - 10.1016/S0014-2999(98)00454-3. DO - 10.1016/S0014-2999(98)00454-3. M3 - Article. VL - 354. SP - 261. EP - 269. JO - European Journal of Pharmacology. JF - European Journal of Pharmacology. SN - 0014-2999. IS - 2-3. ER - ...
7 (a) The radiologist performs a specimen radiograph to confirm the presence of calcifications in the cores. Calcifications that are faint or few in number may be difficult to detect in tissue sections. The numerous calcifications in this radiograph should be readily apparent in the histologic sections. (b) Large calcifications can chip out of the specimen rather than be sectioned. Only fragments of a calcification may be present, as seen in this case of DCIS. " In this case a large calcification is present next to numerous smaller difficult to see calcifications (arrows). The node can appear on mammography as an oval masscontaining calcifications. The gold forms black granular masses that resemble anthracotic pigment. Calcifications have dissolved in fixative. Prolonged time in formalin over several days can result in the disappearance of radiologic calcifications [21]. This should never happen with routine processing occurring within 1-2 days. Formalin must be properly buffered ...
An electroplating apparatus and method reduces oxidation of thermodynamically unstable and oxidizable ionic species in an electroplating solution to deposit complex magnetic alloy onto substrates. The electroplating apparatus comprises an electroplating cell (30) in which oxidation of oxidizable anions and cations is reduced. The cell comprises an anode compartment (110) with anolyte solution in contact with the anode (55), a cathode compartment (105) with catholyte solution containing oxidizable plating anions in contact with the cathode (50). A cation selective membrane (100) separates the electrode compartments. Upon application of a voltage or power supply (90) across the anode and cathode, the transport of oxidizable plating anions and to a lesser degree cations, to the anode is substantially blocked by the cation-selective semi-permeable membrane, thereby reducing oxidation of the oxidizable anions and cations at the anode. The concentration of the anolyte and catholyte solutions can be
Organic cation transporters in the kidney and liver play an important role in the removal of potentially toxic drugs and their metabolites from the systemic circulation (Zhang et al., 1998a). The fundamental mechanisms involved in the sequential flux of organic cations across renal and hepatic epithelia are reported to be similar among mammalian species (Pritchard and Miller, 1993, 1996; Zhang et al., 1998a). However, the extent of interspecies differences in kinetic characteristics and selectivities of organic cation transporters is not well understood. Our understanding of organic cation transport mechanisms is largely based on studies performed with tissue preparations from the rabbit kidney and rat liver (Wright, 1985;Gisclon et al., 1987; Dantzler et al., 1991; Moseley et al., 1992,1996, 1997; Martel et al., 1996). Relatively few studies have examined renal or hepatic transport mechanisms in humans (Ott et al., 1991; Chun et al., 1997; Muller and Jansen, 1997). There have been several ...
Photoinitiated reactions in van der Waals complexes provide a means to examine reactive pathways from well-defined initial geometries. In recent work, we re-examined reactive pathways following resonant two-photon ionization (R2PI) of the chlorobenzene-ammonia (PhCl⋯NH3) dimer. The dimer cation radical reacts primarily via Cl atom loss, and additional channels corresponding to HCl and H atom loss were identified. The structure of the reactive complex was confirmed as an in-plane σ-type, and computational studies of the dimer cation radical potential energy landscape revealed two nearly isoenergetic arenium ion intermediates (or Wheland intermediates). The intermediate produced from ipso addition was not stable with respect to either Cl or HCl loss, and the relative branching observed in experiment was well reproduced by microcanonical transition state theory (TST) calculations. Here, we report experimental and computational studies of the related PhBr⋯NH3 dimer, examined for the first time. We
 An electric field is the effect an electric charge has on other charges in the space around it.  The strength of an electric field is dependant on 2 things.  1. amount of charge producing the field.  2. distance from the charge.  The further the 2 charges are away from each other, the less force they feel.  The closer the 2 charges are, the more force they feel.
article{9e981584-ee0b-4f80-867b-a0b6814c78bd, author = {Belting, Mattias and Petersson, Per}, language = {eng}, pages = {281--286}, series = {Biochem. J.}, title = {Protective role for proteoglycans against cationic lipid cytotoxicity allowing optimal transfection efficiency in vitro}, year = {1999 ...
Ellibs Ebookstore - Ebook: Carbon-Centered Free Radicals and Radical Cations: Structure, Reactivity, and Dynamics - Author: Forbes, Malcolm D. - Price: 127,20€
Electrons get pulled in when there is a higher positive charge (there are more protons) which is why they get smaller. This explains why cations are smaller than anions. Cations have lost some amount of electrons but still have the same number of protons as the neutral atom (this is why its still the same element as the neutral atom) so less electrons means that the nucleus has less electrons to hold on to, which causes the remaining electrons to be pulled in further by the protons and decreasing the atomic radius. Anions are bigger for the opposite reason, they gain electrons so the protons have more electrons to hold on to than they would in the neutral atom which causes the electrons to be more spread out creating a larger atomic radius ...
SPE Part: 8B-S035-JDG Strata™-X-CW 33 µm Polymeric Weak Cation, 1 g / 12 mL, Giga Tubes , 20/Pk Phase: Polymeric weak cation exchange Sorbent Type: Polymer-based Format: Tube Target Analytes: Basic compounds, particularly strong bases
SPE Part: 8B-S035-HCH Strata™-X-CW 33 µm Polymeric Weak Cation, 500 mg / 6 mL, Tubes , 30/Pk Phase: Polymeric weak cation exchange Sorbent Type: Polymer-based Format: Tube Target Analytes: Basic compounds, particularly strong bases
Heyes CD, Wang J, Sanii LS, EL-Sayed MA. Fourier transform infrared study of the effect of different cations on bacteriorhodopsin protein thermal stability. Biophysical journal [Internet]. 2002 ;82(3):1598-1606. Available from: http://dx.doi.org/10.1016/S0006-3495(02)75511-2 ...
Page contains details about DNA-chromophore array-incorporated cationic lipid multilamellar nanostructures . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Cation Workwear & Uniform is a unifrom producer such as overalls, coats, vests, t-shirts, aprons, trousers, shirts, s-shirts and uniforms.
Our research interests involve the combined application of theory and experiment in structural-mechanistic studies. Our research work is centered on the generation and investigation of electron deficient carbocations by NMR spectroscopy, ab initio, DFT, IGLO and GIAO calculations. This include the structures of some of the most important carbocation intermediates, effects of heteroatoms on the stability of carbocations and their role in the electrophilic substitution reactions.. Our work is also concerned with the possible role of onium dications (superelectrophiles) in superacid catalyzed reactions. Some electrophiles, such as carboxonium ions, nitronium ion and related systems are capable of further interaction with Bronsted or Lewis superacids can be greatly activated in superacidic systems. Such further interactions produce superelectrophiles, which are highly reactive, energetic, high lying intermediates of dipositive nature. They are the de facto reactive intermediates (such as NO2H2+, ...
My mom ran low on cations Saturday; we went to lunch, and the battery in her car died. Many thanks to the extremely lovely lady at the restaurant who gave us a jump, and to the two great folks at Advance Auto Parts who installed a new battery. It cut into our antiquing, but I was glad I could help her and that it hadnt happened when my stepfather was in crisis ...
mode, was anticipated by work with more intensively These additional catalytic modes, which will be detailed studied Tet proteins and was confirmed by Yamaguchi et further below, have in common the use of cationic al. (1995) and Guffanti and Krulwich (1995). Modes II and substrates with single net charge, but the cytoplasmic III, the Monovalent cation/H+ Antiport and Monovalent substrates range from a Tc- -Me2+ complex that has regions cation or Tc- -Me2+/K+ Antiport (the Net K+ Uptake Mode), with highly non-polar features to highly hydrated respectively, were unanticipated, although Ives and Bott monovalent cations. The substrate diversity of Tet(L) and (1990) speculated that tetL was likely to have a Tc-unrelated Tet(K) opens up some of the same questions that are function of physiological significance. Chromosomally central to function of those MDRs whose substrates encoded Tet(L) from Bacillus subtilis was identified as a encompass diverse structures and both non-polar and polar possible ...
1aek: Artificial protein cavities as specific ligand-binding templates: characterization of an engineered heterocyclic cation-binding site that preserves the evolved specificity of the parent protein.
Thermal studies on CuCr2O4 spinel indicated the phase present above 870 K to be cubic CuCr2O4. However, when the substance was quenched from 1023 K, 1173 K, 1273 K and 1473 K, only the tetragonal...
Nancy E. Brown, Alexandra Navrotsky; Hematite-ilmenite (Fe 2 O 3 -FeTiO 3 ) solid solutions; the effects of cation ordering on the thermodynamics of mixing. American Mineralogist ; 79 (5-6): 485-496. doi: Download citation file:. ...
대전광역시 유성구 대학로 245 한국과학기술정보연구원TEL : 042.869.1234 서울시 동대문구 회기로 66NDSL고객센터 : 080.969.4114E-mail : [email protected] 대표자 : 한선화사업자등록번호 : 205-82-04043 ...
League of Legends Summoner data for Cation Anion 990161 in br. Contains statistics, match data and more to help players analyze and improve performance.
Using Periodic Properties to Identify Group 2A Cations and Group 7A Anions Objectives The objectives of this lab are as follows: To observe the solubility properties of various ionic compounds containing
Macroporous Strong acid Cation resin with oxidation resistant, such as nitric acid,recovery metal in a strong oxidation media.recovery Cu,V from adipic acid
C60 cations[edit]. C60 oxidizes with difficulty. Three reversible oxidation processes have been observed by using cyclic ... Redox reactions - C60 anions and cations[edit]. C60 anions[edit]. See also: Fullerides ... 7.7 Redox reactions - C60 anions and cations *7.7.1 C60 anions ...
Identification of alkaline earth cations[edit]. The flame test The table below[74] presents the colours observed when the flame ... which the alkaline earth metals readily lose to form cations with charge +2, and an oxidation state of +2.[5] ...
Cation exchange[edit]. Cation exchange sorbents are derivatized with functional groups that interact and retain positively ... Strong cation exchange sorbents contain aliphatic sulfonic acid groups that are always negatively charged in aqueous solution, ... Strong cation exchange sorbents are useful because any strongly basic impurities in the sample will bind to the sorbent and ... and weak cation exchange sorbents contain aliphatic carboxylic acids, which are charged when the pH is above about 5. ...
Guanidinium cation[edit]. The conjugate acid is called the guanidinium cation, (C(NH. 2)+. 3). This planar, symmetric ion ... Via the intermediacy of biguanidine, this ammonolysis step affords salts of the guanidinium cation (see below). In the second ... 1 cation in aqueous solution due to the efficient resonance stabilization of the charge and efficient solvation by water ...
Anion/cation analysis[edit]. See also: Qualitative inorganic analysis. Precipitate formation is useful in the detection of the ... To identify the cation, the color of the precipitate and its solubility in excess are noted. Similar processes are often used ... type of cation in a salt. To do this, an alkali first reacts with the unknown salt to produce a precipitate that is the ...
Flavylium cation derivatives[edit]. Main article: Anthocyanidin. Selected anthocyanidins and their substitutions Basic ... October 2008). "Singlet oxygen quenching by anthocyanin's flavylium cations". Free Radical Research. 42 (10): 885-91. doi: ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
NMDARs can open only when a depolarization from the AMPAR activation leads to repulsion of the Mg2+ cation out into the ... AMPA receptors (AMPAR) are both glutamate receptors and cation channels that are integral to plasticity and synaptic ... The AMPAR's permeability to calcium and other cations, such as sodium and potassium, is governed by the GluA2 subunit. If an ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
In sufficiently acidic environments, the amino group gains a proton and the molecule becomes a cation with a single positive ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
TCN-213; Cations: Hydrogen. *Magnesium. *Zinc; Alcohols/volatile anesthetics/related: Benzene. *Butane ...
Other cations. Potassium ferrocyanide Except where otherwise noted, data are given for materials in their standard state (at 25 ...
Other cations. Sulfur dioxide. Selenium dioxide Related tellurium oxides. Tellurium trioxide. Tellurium monoxide ...
Other cations. Sodium persulfate. Potassium persulfate Except where otherwise noted, data are given for materials in their ...
Other cations. Magnesium sulfate. Strontium sulfate. Barium sulfate Related desiccants. Calcium chloride. Magnesium sulfate ...
Other cations. Monosodium phosphate. Monoammonium phosphate Related compounds. Dipotassium phosphate. Tripotassium phosphate ...
In the solid phase, the observed N=N and N−F bond distances in the N2F+ cation are 1.089(9) and 1.257(8) Å respectively, among ...
Other cations. Vanadium(III) sulfate Related compounds. Vanadyl acetylacetonate Except where otherwise noted, data are given ...
Polymeric uranium(VI) fluorides containing organic cations have been isolated and characterised by X-ray diffraction.[10] ...
and one hydronium cation (H. 3O+. ). Because water is such a good solvent, it almost always has some solute dissolved in it, ... cations and Cl−. anions, each being surrounded by water molecules. The ions are then easily transported away from their ...
Transient receptor potential cation channel subfamily V member 1. Details. Name. Transient receptor potential cation channel ... Transient receptor potential cation channel subfamily V member 1. Q8NER1. Details. Drug Relations. Drug Relations. DrugBank ID ...
A-Putative-Cation-Channel-NCA-1-and-a-Novel-Protein-UNC-80-Transmit-Neuronal-Activity-in-C.-elegans-pbio.0060055.sv001.ogv 16 s ... A-Putative-Cation-Channel-NCA-1-and-a-Novel-Protein-UNC-80-Transmit-Neuronal-Activity-in-C.-elegans-pbio.0060055.sv002.ogv 20 s ... A-Putative-Cation-Channel-NCA-1-and-a-Novel-Protein-UNC-80-Transmit-Neuronal-Activity-in-C.-elegans-pbio.0060055.sv003.ogv 11 s ... A-Putative-Cation-Channel-NCA-1-and-a-Novel-Protein-UNC-80-Transmit-Neuronal-Activity-in-C.-elegans-pbio.0060055.sv004.ogv 33 s ...
The dihydrogen cation or hydrogen molecular ion is a cation (positive ion) with formula H+. 2. It consists of two hydrogen ... An electron is knocked off leaving the cation behind.[16] H2 + cosmic ray → H+. 2 + e− + cosmic ray.. Cosmic ray particles have ... 2 (ditritium cation). [4]. Quantum mechanical analysis[edit]. The Schrödinger equation (in the clamped-nuclei approximation) ... The dihydrogen cation has six isotopologues, that result from replacement of one or more protons by nuclei of the other ...
We are so excited to hear from you! We cant wait to virtually explore this years Vacation Bible School with you. -God Bless, Libby Burkhart and Alexis ...
cation exchange Process in which cations in solution are exchanged with cations held on the exchange sites of mineral and ... cation exchange Process in which cations in solution are exchanged with cations held on the exchange sites of mineral and ... cation exchange A Dictionary of Earth Sciences © A Dictionary of Earth Sciences 1999, originally published by Oxford University ... www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/cation-exchange ...
... has role antioxidant (CHEBI:22586) cyanidin cation (CHEBI:27843) has role metabolite (CHEBI:25212 ... cyanidin cation (CHEBI:27843) is a 5-hydroxyanthocyanidin (CHEBI:140277) cyanidin cation (CHEBI:27843) is conjugate acid of ... cyanidin cation (CHEBI:27843). cyanidin 3-O-rutinoside (CHEBI:28064) has functional parent cyanidin cation (CHEBI:27843). ... cyanidin cation (CHEBI:27843). cyanin (CHEBI:3978) has functional parent cyanidin cation (CHEBI:27843). cyanin betaine (CHEBI: ...
... is a elemental copper (CHEBI:37404) copper cation (CHEBI:23378) is a transition element cation ( ... copper(1+) (CHEBI:49552) is a copper cation (CHEBI:23378). copper(2+) (CHEBI:29036) is a copper cation (CHEBI:23378). copper(3+ ... CHEBI:23378 - copper cation. Main. ChEBI Ontology. Automatic Xrefs. Reactions. Pathways. Models. ...
Thank you for your interest in spreading the word about Science.. NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.. ...
Triethylsilyl Cations. By J. B. Lambert, George A. Olah, Golam Rasul, Xing-ya Li, Herwig A. Buchholz, Graham Sandford, G. K. ... Triethylsilyl Cations. By J. B. Lambert, George A. Olah, Golam Rasul, Xing-ya Li, Herwig A. Buchholz, Graham Sandford, G. K. ... Triethylsilyl Cations. By J. B. Lambert, George A. Olah, Golam Rasul, Xing-ya Li, Herwig A. Buchholz, Graham Sandford, G. K. ...
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Introduction Cation is a drawless connection game for two players: Black and White. Its played on the intersections (points) ...
The National Institute of Standards and Technology (NIST) uses its best efforts to deliver a high quality copy of the Database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. However, NIST makes no warranties to that effect, and NIST shall not be liable for any damage that may result from errors or omissions in the Database ...
Go To: Top, Gas phase thermochemistry data, Ion clustering data, References, Notes. Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved. Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias. Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below. ...
Engelking, P.C.; Smith, A.L., Tunable laser fluorescence spectroscopy of the molecular nitrogen cation at 390 nm, Chem. Phys. ...
Infrared spectra of the CF3+, CF2X+, and CF3X+ cations in solid argon, J. Am. Chem. Soc., 1978, 100, 7, 2102, https://doi.org/ ...
C-Xe Bond strength in the methylxenonium cation determined from ion cyclotron resonance methyl cation exchange equilibria, J. ... Crofton, M.W.; Kreiner, W.A.; Jagod, M.-F.; Rehfuss, G.D.; Oka, T., Observation of the infrared spectrum of methyl cation CH+3 ... McMahon, T.; Heinis, T.; Nicol, G.; Hovey, J.K.; Kebarle, P., Methyl Cation Affinities, J. Am. Chem. Soc., 1988, 110, 23, 7591 ... Dopfer, O.; Olkhov, R.V.; Maier, J.P., Microsolvation of the methyl cation in neon: Infrared spectra and ab initio calculations ...
Some effects of divalent cations on binding and engulfment of several metal oxides and carbon particles are... ... Anionic Group Divalent Cation Peritoneal Macrophage Carbon Particle Fe203 Particle These keywords were added by machine and not ... Metzger G.V., Casarett L.J. (1967) Some Effects of Divalent Cations on In Vitro Phagocytosis. In: Luzio N.R.D., Paoletti R. ( ... Some effects of divalent cations on binding and engulfment of several metal oxides and carbon particles are described. ...
The preparation of betaine cations of methine dyes by three methods, viz., cyanine condensations of some quaternary salts and ...
Plan a Bae-cation Now. It doesnt have to be Valentines Day to plan a bae-cation. In fact, you should plan more than one get ... Bae-cations Can Improve your Global Intelligence, Together. Bae-cations can also improve ones full understanding of diversity ... Taking a bae-cation gives you the time to strengthen your relationship and also improve your work life. Youll return to work ... Bae-cations might sound like a silly Millennial term thats better used to describe an MTV reality show, but these getaways can ...
A unified nomenclature for the superfamily of TRP cation channels. Mol Cell. 2002;9:229-31.PubMedPubMedCentralCrossRefGoogle ... Harteneck C. Function and pharmacology of TRPM cation channels. Naunyn Schmiedebergs Arch Pharmacol. 2005;371:307-14.PubMed ... Vriens J, Appendino G, Nilius B. Pharmacology of vanilloid transient receptor potential cation channels. Mol Pharmacol. 2009;75 ... Harteneck C. (2018) TRP (Transient Receptor Potential Cation Channel). In: Choi S. (eds) Encyclopedia of Signaling Molecules. ...
It was like my very own "stay-cation" for one. By the time my family got home on Sunday afternoon, I was in a state of Jell-O- ...
Edu-ca-tion. Uploaded on Jan 19, 2016 / 359 views / 8016 impressions / 0 comments ...
Summer stay-cations are a great way to have fun without the hassle and expense of leaving town. Find 10 great summer stay- ... So, this year, why not enjoy time off on your own terms with a stay-cation? Youll skip the hassle and the expense of flying or ... No matter what your interests or budget, these 10 great summer stay-cation ideas can help you make the most of your vacation ...
Can you name the Common Monatoma Cations and Anions? Test your knowledge on this science quiz to see how you do and compare ... Science Quiz / Common Monatomic Cations Random Science Quiz Can you name the Common Monatoma Cations and Anions?. by ...
Irvine W.M. (2014) Methylidyne Cation. In: Amils R. et al. (eds) Encyclopedia of Astrobiology. Springer, Berlin, Heidelberg. * ...
  • The presence of isolated metal cations, far from any other atom, is not uncommon in protein crystal structures. (mdpi.com)
  • A systematic survey of the Protein Data Bank showed that nearly 8% of the metal cations are naked, more frequently if they can interact only electrostatically with their neighbors. (mdpi.com)
  • It has been repeatedly observed that metal cations are sometimes isolated in protein crystal structures, far from any other atom [ 1 , 2 , 3 ]. (mdpi.com)
  • 150,916 files) was scanned, and only X-ray crystal structures containing metal cations and refined to at least 4 Å resolution were retained. (mdpi.com)
  • This resulted in 53,669 PDB entries containing 237,105 metal cations, the most common of which are shown in Table 1 . (mdpi.com)
  • Table S1 (Supplementary Materials) lists all isolated metal cations. (mdpi.com)
  • In aqueous solution and in other donor solvents, metal cations are surrounded by between 4 and 9 solvent molecules in the primary solvation shell, but the nature of solvation of anions is mostly unknown. (wikipedia.org)
  • Citing earlier work on the dissolution of potassium in 16-crown-4, he realized that the cyclic polyethers represented a new class of complexing agents that were capable of binding alkali metal cations. (wikipedia.org)
  • Many metal cations are also required in the process. (wikipedia.org)
  • Observations made by Saul Winstein and others suggested that highly delocalized and symmetric intermediates were present in the reactions of various substituted norbornyl cations, evidence for non-classical ions. (wikipedia.org)
  • The trihydrogen cation, also known as protonated molecular hydrogen or H+ 3, is one of the most abundant ions in the universe. (wikipedia.org)
  • Cation diffusion facilitators (CDFs) are transmembrane proteins that provide tolerance of cells to divalent metal ions, such as cadmium, zinc, and cobalt. (wikipedia.org)
  • Non-classical ions can be defined as organic cations in which electron density of a filled bonding orbital is shared over three or more centers and contains some sigma-bond character. (wikipedia.org)
  • The 2-norbornyl cation is seen as the prototype for non-classical ions. (wikipedia.org)
  • Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR+ 4, R being an alkyl group or an aryl group. (wikipedia.org)
  • With tripositive ions the high charge on the cation polarizes the water molecules in the first solvation shell to such an extent that they form strong enough hydrogen bonds with molecules in the second shell to form a more stable entity. (wikipedia.org)
  • Understanding of the nature of aqua ions is helped by having information on the nature of solvated cations in mixed solvents and non-aqueous solvents, such as liquid ammonia, methanol, dimethyl formamide and dimethyl sulfoxide to mention a few. (wikipedia.org)
  • The ions are atoms that have gained one or more electrons (known as anions, which are negatively charged) and atoms that have lost one or more electrons (known as cations, which are positively charged). (wikipedia.org)
  • The electrostatic attraction between the anions and cations leads to the formation of a solid with a crystallographic lattice in which the ions are stacked in an alternating fashion. (wikipedia.org)
  • The compound is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions. (wikipedia.org)
  • Common carbenium ions are trityl and tropylium cations. (wikipedia.org)
  • It differs from this value in elemental fluorine, where the atoms are bonded to each other and thus at oxidation state 0, and a few polyatomic ions: the very unstable anions F− 2 and F− 3 with intermediate oxidation states exist at very low temperatures, decomposing at around 40 K. Also, the F+ 4 cation and a few related species have been predicted to be stable. (wikipedia.org)
  • In the original publication the data were obtained by reactions of selected nucleophiles with selected electrophilic carbocations such as tropylium or diazonium cations: or (not displayed) ions based on Malachite green. (wikipedia.org)
  • Most fluids contain ions, positive (cations) and negative (anions). (wikipedia.org)
  • Aqueous solutions universally contain positive and negative ions (cations and anions, respectively), which interact with partial charges on the surface, adsorbing to and thus ionizing the surface and creating a net surface charge. (wikipedia.org)
  • The TRP-ML1 protein (Mucolipin-1) has been shown to be a lysosomal monovalent cation channel that undergoes inactivating proteolytic cleavage. (wikipedia.org)
  • The identification of these proteins as members of the CPA2 family reveals that monovalent cation transport is required for Bacillus spore formation and germination. (wikipedia.org)
  • The Monovalent Cation:Proton Antiporter-1 (CPA1) Family (TC# 2.A.36) is a large family of proteins derived from Gram-positive and Gram-negative bacteria, blue-green bacteria, archaea, yeast, plants and animals. (wikipedia.org)
  • One member, CzcD of Bacillus subtilis (TC# 2.A.4.1.3) , has been shown to exchange the divalent cation (Zn2+ or Cd2+ ) for two monovalent cations (K+ and H+ ) in an electroneutral process energized by the transmembrane pH gradient. (wikipedia.org)
  • The attachment or release of these microbially derived organic biopolymers and recalcitrant influent substrate may depend on the monovalent-to-divalent cation ratio and the concentration of iron. (ingentaconnect.com)
  • PKD2 and polycystin-L have been shown to exhibit voltage-, pH- and divalent cation-dependent channel activity. (wikipedia.org)
  • This entry represents a conserved aspartate residue involved in divalent cation binding [ PMID: 9003755 ]. (ebi.ac.uk)
  • You should time when you take your antibiotic and your other medicine so that you do not take: ---ciprofloxacin for at least 2 hours before or 6 hours after oral cations. (webmd.com)
  • delafloxacin for at least 2 hours before or 6 hours after oral cations. (webmd.com)
  • The most studied cationinteractions involve binding between an aromatic π system and an alkali metal or nitrogenous cation. (wikipedia.org)
  • The optimal interaction geometry places the cation in van der Waals contact with the aromatic ring, centered on top of the π face along the 6-fold axis. (wikipedia.org)
  • It was found that interaction energies of cation-π pairs correlate well with electrostatic potential above the π face of arenes: for eleven Na+-aromatic adducts, the variation in binding energy between the different adducts could be completely rationalized by electrostatic differences. (wikipedia.org)
  • Indeed, Winstein noticed that the only fundamental difference between this aromatic propenyl cation and his non-classical hexyl cation was the fact that, in the latter ion, conjugation is interrupted by three -CH 2- units. (wikipedia.org)
  • It attracted attention as the smallest example of an aromatic cation. (wikipedia.org)
  • Since cation- π interactions are predicted by electrostatics, it follows that cations with larger charge density interact more strongly with π systems. (wikipedia.org)
  • These results improve our understanding of the essential role of cations in the biological function of bpDNase I. The high degree of conservation of the amino acids involved in the identified cation-binding sites across DNase I and DNase I-like proteins from various species suggests that our findings generally apply to all DNase I-DNA interactions. (nih.gov)
  • Since this is not an analysis of the stereochemistry of the metal first coordination spheres, any type of contact between a metal ion and other atoms was considered, independently of the type of metal cation, its oxidation state, its spin state, its coordination number, and independently of the type of atom(s) surrounding the metal and of the type of interatomic interactions (covalent, ionic). (mdpi.com)
  • Well-behaved cation interactions. (wikipedia.org)
  • cation exchange Process in which cations in solution are exchanged with cations held on the exchange sites of mineral and organic matter , particularly on the surfaces of colloids of clay and humus . (encyclopedia.com)
  • In organic chemistry, the term 2-norbornyl cation (equivalent with 2-bicyclo-[2.2.eptyl cation) describes one of the three carbocations formed from derivatives of norbornane. (wikipedia.org)
  • Cation-exchange capacity arises from various negative charges on soil particle surfaces, especially those of clay minerals and soil organic matter. (wikipedia.org)
  • Organic matter also makes a very significant contribution to cation exchange, due to its large number of charged functional groups. (wikipedia.org)
  • P. Singla, R. Mehta and S. Upadhyay, "Clay Modification by the Use of Organic Cations," Green and Sustainable Chemistry , Vol. 2 No. 1, 2012, pp. 21-25. (scirp.org)
  • An organic cation transport protein mediates the transport of organic cations across the cell membrane. (wikipedia.org)
  • Most heavily studied derivatives are those with alkali metals, but fullerides have been prepared with organic cations. (wikipedia.org)
  • The first comprehensive theoretical investigation of aromaticity in functionalized corannulene cations of general formula [CH 3 -C 20 H 10 ] + was accomplished. (rsc.org)
  • He drew direct connections between poor quality forage crops, and ill health in livestock and from this developed a formula for ideal ratios of cations in the soil, the Base Cation Saturation Ratio. (wikipedia.org)
  • A metal ion in aqueous solution (aqua ion) is a cation, dissolved in water, of chemical formula [M(H2O)n]z+. (wikipedia.org)
  • In chemistry, chloryl refers to a triatomic cation with chemical formula ClO+ 2. (wikipedia.org)
  • The cyclopropenium ion is the cation with the formula C3H3+. (wikipedia.org)
  • This entry represents the cation:proton antiporter family 1 (CPA1), which includes Na+/H+ exchangers, K+/H+ exchangers and Na+(K+,Li+,Rb+)/H+ exchangers. (ebi.ac.uk)
  • Gene and pseudogene of the mouse cation-dependent mannose 6-phosphate receptor. (ebi.ac.uk)
  • In the fields of biochemistry and cell biology, the cation-dependent mannose-6-phosphate receptor (CD-MPR) also known as the 46 kDa mannose 6-phosphate receptor is a protein that in humans is encoded by the M6PR gene. (wikipedia.org)
  • The cell surface receptor for insulin-like growth factor 2 also functions as a cation-independent mannose 6-phosphate receptor. (wikipedia.org)
  • The present invention relates to cation exchange membranes for electrochemical cells, and to their use, especially for the electrolysis of alkali metal chloride solutions to make relatively concentrated alkali metal hydroxide. (google.com)
  • The cation exchange membrane according to the present invention can be used in electrolysis of an aqueous alkali metal halide solution under more severe conditions than those conventionally used while maintaining excellent performance stably for a long time. (google.com)
  • alkali metal fullerides can be subjected to cation metathesis. (wikipedia.org)
  • The dihydrogen cation is of great historical and theoretical interest because, having only one electron, the equations of quantum mechanics that describe its structure can be solved in a relatively straightforward way. (wikipedia.org)
  • The Schrödinger equation (in the clamped-nuclei approximation) for this cation can be solved in a relatively straightforward way due to the lack of electron-electron repulsion ( electron correlation ). (wikipedia.org)
  • In 1973, G. Olah was able to directly observe the 2-norbornyl cation by low-temperature NMR and confirm the presence of a non-classical 2-norbornyl cation, allowing the field to reach some conclusions about the possibilities of 3 center - 2 electron bonds involving carbon. (wikipedia.org)
  • Transition metals have the ability to share electron density with π-systems through d-orbitals, creating bonds that are highly covalent in character and cannot be modeled as a cation-π interaction. (wikipedia.org)
  • While the majority of chemists believed that a three-center two-electron bond best depicted its ground state electronic structure, others argued that all data concerning the 2-norbornyl cation could be explained by depicting it as a rapidly equilibrating pair of cations. (wikipedia.org)
  • At the height of the debate, all chemists agreed that the delocalized picture of electron bonding could be applied to the 2-norbornyl cation. (wikipedia.org)
  • As a result, weakly electronegative atoms tend to distort their electron cloud and form cations. (wikipedia.org)
  • As such, in general, cations are smaller than the corresponding parent atom or molecule due to the smaller size of its electron cloud. (wikipedia.org)
  • Electron capture dissociation of multiply charged protein cations. (wikipedia.org)
  • The fluorescence spectra of the calcium and sodium complexes in acetonitrile show two bands different from the fluorescence of the free probes, one from the excited complex similar to the fluorescence of the protonated probes and the other one from the nitrogen decoordinated cation complexes. (springer.com)
  • Compared to other reactive intermediates such as radicals and carbanions, the vinyl cation long remained poorly-understood and were initially thought to be too high energy to form as reactive intermediates. (wikipedia.org)
  • Typically alkyl cations are generated using super acids, alkyl anions are observed in the presence of strong bases, and alkyl radicals are generated by a photochemical reaction. (wikipedia.org)
  • Cation Radicals" (PDF). (wikipedia.org)
  • They catalyze cation:proton antiport, have a single essential zinc-binding site within the transmembrane domains of each monomer within the dimer, and have a binuclear zinc-sensing and binding site in the cytoplamsic C-terminal region. (wikipedia.org)
  • The Polycystin Cation Channel (PCC) Family (TC# 1.A.5) consists of several transporters ranging in size from 500 to over 4000 amino acyl residues (aas) in length and exhibiting between 5 and 18 transmembrane segments (TMSs). (wikipedia.org)
  • The predicted seven-transmembrane α helices of ChR2 are characteristic for G protein-coupled receptors but reflect a different motif for a cation-selective ion channel. (pnas.org)
  • Control of the radical-cation pairs are difficult and often depend on the monomer and reaction conditions. (wikipedia.org)
  • The cation-dependent mannose 6-phosphate (M6P) receptor (CD-MPR) is present predominantly as a stable homodimer in membranes and has a single M6P-binding site per polypeptide [ PMID: 2954652 , PMID: 2544594 ]. (ebi.ac.uk)
  • What stay-cations are available in Ireland this autumn? (irishexaminer.com)
  • I fell in love with the idea of stay-cations after taking my first one. (lifehack.org)
  • Hydrogen-bridged cations are a type of charged species in which a hydrogen atom is simultaneously bonded to two atoms through partial sigma bonds. (wikipedia.org)
  • Figure 1 - Potential Energy Surface (PES) of (a) classical and (b) non-classical view of a hydrogen-bridged cation. (wikipedia.org)
  • Any intermediating solvent molecule will attenuate the effect, because the energy gained by the cation-π interaction is partially offset by the loss of solvation energy. (wikipedia.org)
  • These ratios can be between individual cations, such as the calcium to magnesium ratio, or they may be expressed as a percentage saturation of the cation exchange capacity (CEC) of the soil. (wikipedia.org)
  • The SN1 solvolysis chemistry used to produce other vinyl cations has not proven facile for the cycloprop-1-enyl cation. (wikipedia.org)
  • The DCC1000e is a degassed cation conductivity system that provides ASTM D4519-compliant conductivity measurements for cycle chemistry monitoring. (mt.com)
  • Understanding organofluorine chemistry and in cations. (wikipedia.org)
  • Studying these cations was sparked, at the time, by amazing results in computational chemistry. (wikipedia.org)
  • In the BCSR system, soil cations are balanced according to varying ratios often stated as giving 'ideal' or 'balanced' soil. (wikipedia.org)
  • From the late 1930s, William Albrecht, the Chairman of the Department of Soils at the University of Missouri, began work at the Missouri Agricultural Experiment Station investigating cation ratios and the growth of legumes. (wikipedia.org)
  • f ) Permability ratios for different monovalent cations, as derived from changes of reversal potentials ( 31 ) of photocurrents when replacing Na + by the cation X + . Solutions used were: 115 mM XCl, 2 mM BaCl 2 , 1 MgCl 2 , pH 9. (pnas.org)
  • This trend is supported by calculations showing that the vinyl cation prefers a linear arrangement. (wikipedia.org)
  • Extended Hückel Theory calculations for the 2-norbornyl cation suggest that the orbital on carbon 6 could instead be sp2-hybridized, though this only affects the geometry of the geminal hydrogens. (wikipedia.org)
  • Importantly, Poisson-Boltzmann-type electrostatic potential calculations demonstrate that the divalent cations collectively control the electrostatic fit between bpDNase I and DNA. (nih.gov)
  • Advocates of the non-classical nature of the stable 2-norbornyl cation typically depict the species using either resonance structures or a single structure with partial bonds (see Figure 2). (wikipedia.org)
  • The OF+ 3 cation was shown to be vibrationally stable at all levels of theory applied (HF, MP2, CCSD(T)). OF+ 3 was proposed to possess a pyramidal structure with an O-F bond length of 1.395 Å and F-O-F bond angles of 104.2° (CCSD(T) level of theory). (wikipedia.org)