Kinetics: The rate dynamics in chemical or physical systems.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.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)Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)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)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.Enzymes: Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified.Diffusion: The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.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.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Protein 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.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.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.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.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).Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.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.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).Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Protein Synthesis Inhibitors: Compounds which inhibit the synthesis of proteins. They are usually ANTI-BACTERIAL AGENTS or toxins. Mechanism of the action of inhibition includes the interruption of peptide-chain elongation, the blocking the A site of ribosomes, the misreading of the genetic code or the prevention of the attachment of oligosaccharide side chains to glycoproteins.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.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.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.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).Cell Line: Established cell cultures that have the potential to propagate indefinitely.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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Cycloheximide: Antibiotic substance isolated from streptomycin-producing strains of Streptomyces griseus. It acts by inhibiting elongation during protein synthesis.TritiumDNA Replication: The process by which a DNA molecule is duplicated.Leucine: An essential branched-chain amino acid important for hemoglobin formation.Cyclization: Changing an open-chain hydrocarbon to a closed ring. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Carbon Isotopes: Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.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.RNA: A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Bacterial Proteins: Proteins found in any species of bacterium.Dactinomycin: A compound composed of a two CYCLIC PEPTIDES attached to a phenoxazine that is derived from STREPTOMYCES parvullus. It binds to DNA and inhibits RNA synthesis (transcription), with chain elongation more sensitive than initiation, termination, or release. As a result of impaired mRNA production, protein synthesis also declines after dactinomycin therapy. (From AMA Drug Evaluations Annual, 1993, p2015)Cell-Free System: A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)ThymidineAmino Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.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.Puromycin: A cinnamamido ADENOSINE found in STREPTOMYCES alboniger. It inhibits protein synthesis by binding to RNA. It is an antineoplastic and antitrypanosomal agent and is used in research as an inhibitor of protein synthesis.Chemistry Techniques, Synthetic: Methods used for the chemical synthesis of compounds. Included under this heading are laboratory methods used to synthesize a variety of chemicals and drugs.Peptide Biosynthesis: The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Chloramphenicol: An antibiotic first isolated from cultures of Streptomyces venequelae in 1947 but now produced synthetically. It has a relatively simple structure and was the first broad-spectrum antibiotic to be discovered. It acts by interfering with bacterial protein synthesis and is mainly bacteriostatic. (From Martindale, The Extra Pharmacopoeia, 29th ed, p106)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.Recombinant Proteins: Proteins prepared by recombinant DNA technology.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.UridineElectrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Chemistry, Organic: The study of the structure, preparation, properties, and reactions of carbon compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Glucose: A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Molecular Weight: The sum of the weight of all the atoms in a molecule.Indicators and Reagents: Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)Viral Proteins: Proteins found in any species of virus.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Virus Replication: The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.Methionine: A sulfur-containing essential L-amino acid that is important in many body functions.Phenylalanine: An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.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.Acetates: Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.Rats, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.RNA, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.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.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Carbon Radioisotopes: Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Solid-Phase Synthesis Techniques: Techniques used to synthesize chemicals using molecular substrates that are bound to a solid surface. Typically a series of reactions are conducted on the bound substrate that results in either the covalent attachment of specific moieties or the modification of existing function groups. These techniques offer an advantage to those involving solution reactions in that the substrate compound does not have to be isolated and purified between the reaction steps.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Polyribosomes: A multiribosomal structure representing a linear array of RIBOSOMES held together by messenger RNA; (RNA, MESSENGER); They represent the active complexes in cellular protein synthesis and are able to incorporate amino acids into polypeptides both in vivo and in vitro. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Autoradiography: The making of a radiograph of an object or tissue by recording on a photographic plate the radiation emitted by radioactive material within the object. (Dorland, 27th ed)Fatty Acids: Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Enzyme Induction: An increase in the rate of synthesis of an enzyme due to the presence of an inducer which acts to derepress the gene responsible for enzyme synthesis.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Templates, Genetic: Macromolecular molds for the synthesis of complementary macromolecules, as in DNA REPLICATION; GENETIC TRANSCRIPTION of DNA to RNA, and GENETIC TRANSLATION of RNA into POLYPEPTIDES.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.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.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.UracilDNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Palladium: A chemical element having an atomic weight of 106.4, atomic number of 46, and the symbol Pd. It is a white, ductile metal resembling platinum, and following it in abundance and importance of applications. It is used in dentistry in the form of gold, silver, and copper alloys.Molecular Conformation: The characteristic three-dimensional shape of a molecule.Culture Techniques: Methods of maintaining or growing biological materials in controlled laboratory conditions. These include the cultures of CELLS; TISSUES; organs; or embryo in vitro. Both animal and plant tissues may be cultured by a variety of methods. Cultures may derive from normal or abnormal tissues, and consist of a single cell type or mixed cell types.DNA-Directed DNA Polymerase: DNA-dependent DNA polymerases found in bacteria, animal and plant cells. During the replication process, these enzymes catalyze the addition of deoxyribonucleotide residues to the end of a DNA strand in the presence of DNA as template-primer. They also possess exonuclease activity and therefore function in DNA repair.Alkynes: Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.Muscle Proteins: The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.Cell Cycle: The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)Combinatorial Chemistry Techniques: A technology, in which sets of reactions for solution or solid-phase synthesis, is used to create molecular libraries for analysis of compounds on a large scale.EstersAlkenes: Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Oligonucleotides: Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)Phosphates: Inorganic salts of phosphoric acid.Arginine: An essential amino acid that is physiologically active in the L-form.RNA, Ribosomal: The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)Nucleic Acid Synthesis Inhibitors: Compounds that inhibit cell production of DNA or RNA.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Half-Life: The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.Ultraviolet Rays: That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.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.Reticulocytes: Immature ERYTHROCYTES. In humans, these are ERYTHROID CELLS that have just undergone extrusion of their CELL NUCLEUS. They still contain some organelles that gradually decrease in number as the cells mature. RIBOSOMES are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic "reticulum" (not the same as the ENDOPLASMIC RETICULUM), hence the name reticulocytes.Insulin: A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.Glucosyltransferases: Enzymes that catalyze the transfer of glucose from a nucleoside diphosphate glucose to an acceptor molecule which is frequently another carbohydrate. EC 2.4.1.-.Genes, Bacterial: The functional hereditary units of BACTERIA.Phospholipids: Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.Nitric Oxide: A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.Cytoplasm: The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Microscopy, Electron: Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.Glycosides: Any compound that contains a constituent sugar, in which the hydroxyl group attached to the first carbon is substituted by an alcoholic, phenolic, or other group. They are named specifically for the sugar contained, such as glucoside (glucose), pentoside (pentose), fructoside (fructose), etc. Upon hydrolysis, a sugar and nonsugar component (aglycone) are formed. (From Dorland, 28th ed; From Miall's Dictionary of Chemistry, 5th ed)Genes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Depression, Chemical: The decrease in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.Sulfur Radioisotopes: Unstable isotopes of sulfur that decay or disintegrate spontaneously emitting radiation. S 29-31, 35, 37, and 38 are radioactive sulfur isotopes.Cell Survival: The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.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.RNA, Transfer: The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.Furans: Compounds with a 5-membered ring of four carbons and an oxygen. They are aromatic heterocycles. The reduced form is tetrahydrofuran.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Glycerol: A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, and sweetening agent.DNA-Directed RNA Polymerases: Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.Enzyme Repression: The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Collagen: A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).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.Coliphages: Viruses whose host is Escherichia coli.Uracil NucleotidesPromoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Genetic Complementation Test: A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.Isotope Labeling: Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.KetonesPhenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Acyltransferases: Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Urea: A compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.Anisomycin: An antibiotic isolated from various Streptomyces species. It interferes with protein and DNA synthesis by inhibiting peptidyl transferase or the 80S ribosome system.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.Nucleotides: The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)Prostaglandins: A group of compounds derived from unsaturated 20-carbon fatty acids, primarily arachidonic acid, via the cyclooxygenase pathway. They are extremely potent mediators of a diverse group of physiological processes.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Light: That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Emetine: The principal alkaloid of ipecac, from the ground roots of Uragoga (or Cephaelis) ipecacuanha or U. acuminata, of the Rubiaceae. It is used as an amebicide in many different preparations and may cause serious cardiac, hepatic, or renal damage and violent diarrhea and vomiting. Emetine inhibits protein synthesis in EUKARYOTIC CELLS but not PROKARYOTIC CELLS.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Spectrophotometry, Infrared: Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Anti-Bacterial Agents: Substances that reduce the growth or reproduction of BACTERIA.Oligodeoxyribonucleotides: A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.Dinoprostone: The most common and most biologically active of the mammalian prostaglandins. It exhibits most biological activities characteristic of prostaglandins and has been used extensively as an oxytocic agent. The compound also displays a protective effect on the intestinal mucosa.Muscles: Contractile tissue that produces movement in animals.Bacillus subtilis: A species of gram-positive bacteria that is a common soil and water saprophyte.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.Cell Wall: The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.GlycogenDrug Design: The molecular designing of drugs for specific purposes (such as DNA-binding, enzyme inhibition, anti-cancer efficacy, etc.) based on knowledge of molecular properties such as activity of functional groups, molecular geometry, and electronic structure, and also on information cataloged on analogous molecules. Drug design is generally computer-assisted molecular modeling and does not include pharmacokinetics, dosage analysis, or drug administration analysis.Glutamine: A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from GLUTAMIC ACID and AMMONIA. It is the principal carrier of NITROGEN in the body and is an important energy source for many cells.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Mitochondria: Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
... organic synthesis by inorganic salts and polymerization kinetics. In an interview to New Scientist magazine in 1985, Fukui had ... This helps to explain the predictions of the Woodward-Hoffman rules for thermal pericyclic reactions, which are summarized in ... been highly critical on the practices adopted in Japanese universities and industries to foster science. He noted, "Japanese ... His prize-winning work focused on the role of frontier orbitals in chemical reactions: specifically that molecules share ...
Fowler, Joanna S. (1977). "2-Methyl-3-butyn-2-ol as an acetylene precursor in the Mannich reaction. A new synthesis of suicide ... reactivation and aging kinetics of highly toxic organophosphorus compounds with human and pig acetylcholinesterase". Toxicology ... 5-fluorouracil acts as a suicide inhibitor of thymidylate synthase during the synthesis of thymine from uridine. This reaction ... approach is to create substrates that are unreactive until within that enzyme's active site and at the same time being highly ...
Bouveault aldehyde synthesis Bodroux-Chichibabin aldehyde synthesis Reimer-Tiemann reaction Sommelet reaction Vilsmeier-Haack ... Ogata, Y.; Sugiura, F. (1968). "Kinetics and mechanism of the Duff reaction". Tetrahedron. 24 (14): 5001. doi:10.1016/S0040- ... a Highly Enantioselective Epoxidation Catalyst". Org. Synth. 75: 1. doi:10.15227/orgsyn.075.0001. ; Coll. Vol., 10, p. 96 Allen ... The Duff reaction or hexamine aromatic formylation is a formylation reaction used in organic chemistry for the synthesis of ...
Kinetics, and Step-Growth Formation of Highly Cross-Linked Networks". Macromolecules. 42 (1): 211-217. Bibcode:2009MaMol..42.. ... Synthesis of three-dimensional porous hyper-crosslinked polymers via thiol-yne reaction Mathias Lang, Alexandra Schade and ... The Thiol-yne reaction (also alkyne hydrothiolation) is an organic reaction between a thiol and an alkyne. The reaction product ... Another reported application is the synthesis of macrocycles via dithiol coupling. Thiol-ene reaction Click chemistry Radical ...
Atul Kumar has reported multicomponent reaction Hantzsch ester synthesis in Aqueous Micelles using ultrasound.[20] ... For example, in chemical kinetics, it has been observed that ultrasound can greatly enhance chemical reactivity in a number of ... These jets and associated shock waves can damage the now highly heated surface. Liquid-powder suspensions produce high velocity ... The chemical enhancement of reactions by ultrasound has been explored and has beneficial applications in mixed phase synthesis ...
The reaction rate is described as follows: rate = k2[M(CN)42−][CN−], where k2 120 M−1−s−1 The bimolecular kinetics implicate a ... In organic synthesis palladium cyanide is used in the synthesis of olefinic cyanides from olefins. and as a catalyst in the ... possibly with the intermediacy of a highly reactive pentacoordinate species [Pd(CN)5]3−. By comparison, the rate constant for [ ... H2 This reaction is reminiscent of the "cyanide process" for the extraction of gold, although in the latter reaction O2 is ...
To better understand the kinetics of thiol-ene reactions, calculations and experiments of transition-state and reaction ... This free-radical polymerization can be useful in the synthesis of uniform polymer networks. Thiol-ene reactions are known to ... A currently accepted trend is that electron-rich alkenes (vinyl ether, allyl ether, etc.) and norbornene are highly reactive ... This reaction is accepted as a click chemistry reaction given the reactions' high yield, stereoselectivity, high rate, and ...
... trifluoroacetate catalyzed synthesis of 3,4- dihydropyrimidin-2(1H)-ones under solvent-free conditions". Reaction Kinetics and ... doi:10.1016/0040-4039(95)01660-A. Kappe, C. O. (2000). "Highly versatile solid phase synthesis of biofunctional 4-aryl-3,4- ... The reaction mechanism of the Biginelli reaction is a series of bimolecular reactions leading to the desired ... Sweet, F.; Fissekis, J. D. (1973). "Synthesis of 3,4-dihydro-2(1H)-pyrimidinones and the mechanism of the Biginelli reaction". ...
In PiHKAL, Shulgin also notes a cruder method of producing the same product by bringing to reaction olivetol and the essential ... Although olivetol is the decarboxylated form of OLA, it is highly unlikely that OLS produces olivetol from OLA. Crude enzyme ... The data from Taura's study of OLS's enzyme kinetics show that OLS catalyzes a decarboxylative-aldol condensation to produce ... Another method for the stereospecific synthesis of Δ9-tetrahydrocannabinol comprising condensing olivetol with 2-carene oxide. ...
Some of this control originates from the reaction of CTAB with other reagents in the gold nanoparticle synthesis. For example, ... There is a need to prepare highly ordered mesoporous material with good mesoscale crystallinity. The synthesis of mesoporous ... precursor influence the kinetics of the nanoparticle formation reaction and therefore influence the size, shape, and (size and ... The positively charged CTA+ binds to the ATP synthase not allowing H+ to bind stopping the synthesis of ATP and resulting in ...
The metal-carbon bond in organometallic compounds is generally highly covalent. For highly electropositive elements, such as ... Catalyzed Cross-Coupling Reactions Using Alkyl-organometallics as Reaction Partners". Chemical Reviews. 111 (3): 1417-1492. doi ... Organometallic complexes are commonly used in small-scale fine chemical synthesis as well, especially in cross-coupling ... The dynamic properties of organometallic compounds is often probed with variable-temperature NMR and chemical kinetics. ...
... or hydroxyl groups on the alginate reagent form complexes during the synthesis of the AgNPs that stabilize the reaction. ... Stopped-flow spectrometry has been used to characterize the chemical mechanism and kinetics of AgNPs. Oxidative dissolution of ... which attenuate reactivity of the AgNPs by entering into the lattice to form a highly stable Ag6O octahedral structure. It has ... Chen, P., Zhang, X., Miao, Z., Han, B., An, G. & Liu, Z., In-situ Synthesis of Noble Metal Nanoparticles in Alginate Solution ...
In yeast, mutation in the Trigger-Loop domain of the largest subunit can change the kinetics of the enzyme. Bacterial RNA ... Alpha-Amanitin is a highly poisonous substance found in many mushrooms. The mushroom poison has different effects on the each ... A subcomplex of RPB2 and RPB3 appears soon after subunit synthesis. This complex subsequently interacts with RPB1. RPB3, RPB5, ... Enzymes can catalyze up to several million reactions per second. Enzyme rates depend on solution conditions and substrate ...
Therefore, first-order kinetics apply (unimolecular). The reaction usually occurs in the complete absence of a base or the ... E1cB-elimination reaction Coleman, G. H.; Johnstone, H. F. (1925). "Cyclohexene". Organic Syntheses. 5: 33. doi:10.15227/orgsyn ... E1 eliminations happen with highly substituted alkyl halides for two main reasons. Highly substituted alkyl halides are bulky, ... The reaction mechanism involving staggered conformation is more favorable for E2 reactions (unlike E1 reactions). E2 typically ...
... dimer-based reactions are common. A series of solution kinetics studies of LDA - mediated reactions suggest that lower ... 1988). "Enantioselective synthesis using diisopropyl tartrate modified (E)- and (Z)-crotylboronates: Reactions with achiral ... 2006). "Covalency in Highly Polar Bonds. Structure and Bonding of Methylalkalimetal Oligomers (CH3M)n (M = Li−Rb; n = 1, 4)". J ... The kinetics of reaction of n-butyllithium with substituted bromobenzenes in hexane solution". J. Am. Chem. Soc. 104: 522-525. ...
... enzyme kinetics, protein-directed dynamic combinatorial chemistry and organic synthesis/medicinal chemistry. Most clinically ... "Betti reaction enables efficient synthesis of 8-hydroxyquinoline inhibitors of 2-oxoglutarate oxygenases". Chemical ... Highly cited paper awards (e.g. Biochemical Journal, Bioorganic & Medicinal Chemistry Letters) 2009 - 2014: PI of ERC Advanced ... Prof Schofield is currently working on the design and synthesis of enzyme inhibitors for the metallo β-lactamases - there are ...
A. J. P. Domingos, J. A. S. Howell, B. F. G. Johnson, J. Lewis (1990). "Reagents for the Synthesis of η-Diene Complexes of ... Another popular source of Fe(CO)3 is Fe2(CO)9. Alternatively, Fe(CO)3(cyclooctene)2 is highly reactive, the trade-off being ... This red-colored compound is commonly abbreviated (bda)Fe(CO)3. It is prepared by the reaction of Fe2(CO)9 with ... "The kinetics and mechanism of diene exchange in (η4-enone)Fe(CO)2L complexes (L = phosphine, phosphite)". Journal of ...
Synthesis[edit]. Reaction 1: Formation of amino radical from ammonia Amino radicals can be produced by reacting OH radical with ... These rate constants for the amino radical reactions were measured in a 1978 study by Neta et al. by following the kinetics of ... 2). Aminyl are highly reactive and consequently short lived like most radicals; however, they form an important part of ... This reaction is formulated as a hydrogen abstraction reaction.[9] NH3 + •OH → •NH2 + H2O. The rate constant (k1) for this ...
In the area of organic synthesis, the Stille reaction is considered important. It entails coupling reaction with sp2-hybridized ... ISBN 978-3-527-31023-4 Gielen, Marcel (1973). "From kinetics to the synthesis of chiral tetraorganotin compounds". Acc. Chem. ... The Sn centres tend to be highly pyramidal. Monomeric compounds with the formula SnR2, analogues of carbenes are also known in ... Classic is the reaction of a Grignard reagent with tin halides for example tin tetrachloride. An example is provided by the ...
... glycoprotein synthesis, and glycolipid synthesis. The structure of UTP-glucose-1-phosphate uridylyltransferase is significantly ... This reaction is readily reversible and the Gibbs Free Energy is close to zero. However, under typical cellular conditions, ... In higher animals, the enzyme is highly active in tissues involved in glycogenesis, including the liver and the muscles. An ... In yeast, the enzyme follows simple Michaelis-Menten kinetics and does not exhibit cooperativity between the subunits in the ...
Like in RT reactions, the reaction is driven by electronegativity values. The X ligand is attracted to highly electropositive ... Thermodynamics will favor the reaction based on the electronegativities of the metals and kinetics will favor the reaction if ... They have applications to the synthesis of lanthanide complexes, such as in the following reaction: Yb + Sn(N(SiMe3)2)2 → Yb(N( ... Stille reactions use tin, Suzuki reactions use boron, Sonogashira reactions use copper, and Negishi reactions use zinc. The ...
Strategic Applications Of Named Reactions In Organic Synthesis: Background And Detailed Mechanics: 250 Named Reactions. ... The kinetics are of the first order and the whole transformation proceeds through a highly ordered cyclic transition state and ... The Chen-Mapp reaction also known as the [3,3]-Phosphorimidate Rearrangement or Staudinger-Claisen Reaction installs a ... Organic Syntheses, Coll. Vol. 6, p.507; Vol. 58, p.4 (Article) Yu, C.-M.; Choi, H.-S.; Lee, J.; Jung, W.-H.; Kim, H.-J. (1996 ...
Mitochondrial hexokinase is highly elevated in rapidly growing malignant tumor cells, with levels up to 200 times higher than ... The intracellular reactions mediated by hexokinases can be typified as: Hexose-CH2OH + MgATP2− → Hexose-CH2O-PO2− 3 + MgADP− + ... There are four important mammalian hexokinase isozymes (EC that vary in subcellular locations and kinetics with ... such as glycolysis or glycogen synthesis. This is because phosphorylated hexoses are charged, and thus more difficult to ...
The synthesis and characterisation of halogen and nitro phenyl azide derivatives as highly energetic materials. PhD ... Butler, R. N.; Fox, A.; Collier, S.; Burke, L. A. (1998). "Pentazole chemistry: the mechanism of the reaction of aryldiazonium ... kinetics and mechanism of degradation of the arylpentazole system". Journal of the Chemical Society, Perkin Transactions 2 (5 ... Some more highly substituted derivatives, such as 2,6-dihydroxy-4-dimethylaminophenylpentazole, are slightly more stable but ...
"The Inorganic Syntheses Organization". Inorganic Syntheses. Archived from the original on 2011-07-13. "Recent Volumes". ... These enzymes are capable of carry out reaction even in the absence of the protein-based active site organization or carry out ... Kinetics of Tert Butyllithium Dissociation". Journal of the American Chemical Society. 92 (5): 236-242. Darensbourg, Marcetta Y ... However, these Hydrogenase enzymes were found to be highly sensitive with di-oxygen, which can over oxidize and inactivate them ...
This sequence is called a glycosylation sequon. The reaction catalyzed by OST is the central step in the N-linked glycosylation ... ER Translocon complex.[2] Many protein complexes are involved in protein synthesis. The actual production takes place in the ... "STT3, a highly conserved protein required for yeast oligosaccharyl transferase activity in vivo". EMBO J. 14 (20): 4949-60. ... Kinetics. *Enzyme kinetics. *Eadie-Hofstee diagram. *Hanes-Woolf plot. *Lineweaver-Burk plot ...
Kinetics of Elementary Reactions in Cyclic Ester Polymerization; S. Penczek, et al. Synthesis and Properties of Amphiphilic and ... Arborescent Polymers: Highly Branched Homo- and Copolymers with Unusual Properties; M. Gauthier. Similarities and Discrepancies ... Kinetics of the Living Polymerization of Isobutylene; J.E. Puskas, et al. Kinetics and Mechanism of Living Cataionic ... Synthesis, Toughening and Block Copolymerization with Butadiene; K. Knoll, et al. Control of Active Centers Reactivity in the ...
... and reaction kinetics. Rational catalyst design and synthesis include highly dispersed monometallic catalysts, structure- ... "Characterization of MoVTeNbOx catalysts during oxidation reaction using In situ/Operando techniques: a Review" - Catalysts 7.4 ... His research interests include heterogeneous catalysis, catalyst synthesis, ...
polymer synthesis;. *polymer reactions;. *polymerization kinetics;. *polymer physics;. *morphology;. *structure-property ... The scope of the journal covers a wide range of the highly interdisciplinary field of polymer science and technology, including ...
Highly stereoselective synthesis of natural-product-like hybrids by an organocatalytic/multicomponent reaction sequence. Angew ... Kinetics and mechanistic aspects of the Heck reaction promoted by a CN−palladacycle. J Am Chem Soc 127: 12054-12065. [ Links ] ... The intramolecular heck reaction and the synthesis of indolizidinone, quinolizidinone and benzoazepinone derivatives. Synthesis ... Those acquainted with the field of chemical synthesis, highly appreciate earlier demonstrations that highly complex molecular ...
In devising synthetic methodologies to engineered nanomaterials, hydrothermal synthesis and solution combustion synthesis can ... strong exothermic combustion syntheses can benefit from the application of microwaves to convey energy to the reaction not only ... In the first case, energy is transferred to the entire reaction volume, causing a homogeneous temperature rise within a closed ... In both approaches, however, the direct interaction of microwaves with the reaction mixture can lead to practically gradient- ...
J. 2013, 19, 6429). This involves the synthesis of new chiral phosphane catalysts and their subsequent analysis in kinetics ... "Annelated Pyridines as Highly Nucleophilic and Lewis-Basic Catalysts for Acylation Reactions", Chem. Eur. J. 2013, 19, 6435). ... Autoxidation reactions such as the reaction of toluene with oxygen to benzoic acid involve complex interconnected reaction ... "Annelated Pyridines as Highly Nucleophilic and Lewis-Basic Catalysts for Acylation Reactions", Chem. Eur. J. 2013, 19, 6435). ...
... refers to the process of creating organometallic compounds, and is among the most actively researched ... Organometallic Synthesis refers to the process of creating organometallic compounds, and is among the most actively researched ... Monitoring Organometallic Synthesis. Understanding Reaction Mechanisms and Kinetics. Infrared spectroscopy is one of the ... Highly Reactive Chemistries Highly reactive chemistry is a terminology used to describe chemical reactions that are ...
In the field of catalysis, there is a need for highly active, selective, and stable catalysts for more efficient and cleaner ... My graduate research primarily focused on the synthesis of TiO2 nanocrystals with well-defined particle size and ... Then, I developed a mathematical model to describe the types of mechanisms and characterize the kinetics of phase ... model reactions for industrial reforming of naphtha and heavy-gas oil, respectively. In addition, metal-organic framework (MOF ...
The application of in situ Raman spectroscopy and synchrotron X-ray powder diffraction to monitor the reaction of urea pho ... we provide a quantitative investigation of chemical autocatalysis in a mechanochemical reaction. ... mediates the rate of transformation and underpins positive feedback kinetics. The herein observed autocatalysis by water ... In situ monitoring of mechanochemical synthesis of calcium urea phosphate fertilizer cocrystal reveals highly effective water- ...
Existing kinetic models for ampicillin and cephalexin synthesis by PGA do not consider the effects of pH value on the reaction ... 2] Giordano, R. C., Ribeiro, M. P., and Giordano, R. L. (2006) Kinetics of β-lactam antibiotics synthesis by penicillin G ... PGA also hydrolyzes the highly soluble PGME into phenylglycine (termed primary hydrolysis). To maintain a pure solid phase ... potentially deadly allergic reaction) from penicillin, a prevalence of 0.7%.4Enzymatic synthesis of β-lactam antibiotics can ...
Synthesis reactions are perhaps the most common reactions in chemistry. A successful synthesis reaction maximizes the creation ... Synthesis reactions are perhaps the most common reactions in chemistry. A successful synthesis reaction maximizes the creation ... Enhance Understanding of Synthesis Reactions with FTIR & Raman. Gain in-depth information about reaction kinetics, mechanisms, ... highly energetic reactions, air/moisture sensitive, transient intermediates. *Investigate key stages of a reaction or process, ...
Highly Efficient Synthesis of Tricyclic Amines by a Cyclization/Cycloaddition Cascade: Total Syntheses of Aspidospermine, ... Choi A, Morley RM & Coldham I (2019) Synthesis of pyrrolo[1,2-a]quinolines by formal 1,3-dipolar cycloaddition reactions of ... leading to highly enantioenriched 2-substituted cyclic amine products. We have determined the kinetics of enantiomerization of ... Highly efficient synthesis of tricyclic amines by a cyclization/cycloaddition cascade: total syntheses of aspidospermine, ...
... but the kinetics have yet to be studied. Here, kinetics were performed on five consecutive incorporations using various ... Facile Synthesis of N-Acyl-aminoacyl-pCpA for Preparation of Mischarged Fully Ribo tRNA BIOCONJUGATE CHEMISTRY Kwiatkowski, M ... Such aminoacyl-pCpA analogues ligated to tRNA(minus CA) transcripts are highly active in a purified translation system, ... Interestingly, the key chemical step of translation, peptide bond formation, is among the slower enzymatic reactions. The ...
Steady-state kinetics were used to measure Gln-tRNAGln and Glu-tRNAGln synthesis, using a highly sensitive assay in which the 3 ... Aminoacylation Kinetics.. tRNA was 32P-labeled at the 3′ terminal internucleotide linkage by using the exchange reaction of ... WT GlnRS catalyzes Glu-tRNAGln synthesis 107-fold less efficiently than the cognate reaction (18). In considering the ... Fidelity in the expression of the genetic code depends on the accurate synthesis of aminoacyl-tRNAs. These reactions are ...
However, in the reaction of the racemic carbonate rac-1 a as well as of the highly enriched enantiomers 1 a (>/=99 % ee) and ... Also described are the highly selective palladium catalyzed asymmetric syntheses of the cyclic and acyclic allylic tert- ... an overall pseudo-zero order kinetics in regard to the allylic substrate. ... Synthesis of the E-configured allylic sulfides 6 aa, 6 ab, 6 ac and 6 bb was accompanied by the formation of minor amounts of ...
... organic synthesis by inorganic salts and polymerization kinetics. In an interview to New Scientist magazine in 1985, Fukui had ... This helps to explain the predictions of the Woodward-Hoffman rules for thermal pericyclic reactions, which are summarized in ... been highly critical on the practices adopted in Japanese universities and industries to foster science. He noted, "Japanese ... His prize-winning work focused on the role of frontier orbitals in chemical reactions: specifically that molecules share ...
... of carbon-dioxide reducing electrocatalysts that are based on Earth-abundant metals and studies of the reaction kinetics of ... Research in the HTE project involves development of new fabrication systems for combinatorial synthesis of alloys, automated ... and highly selective for specific chemical targets. ... and half-reactions for optimal control of the rate, yield, and ... Molecular Catalysis. The Molecular Catalysis Project involves directed discovery of homogeneous catalysts for the key reactions ...
We here report the controlled synthesis of NiS2/FeS2 nanoparticles encapsulated in N-doped carbon nanorods (NiS2/FeS2/NC) ... The development of cost-effective, highly efficient and robust multi-functional electrode materials can dramatically reduce the ... Multi-functional NiS2/FeS2/N-doped carbon nanorods derived from metal-organic frameworks with fast reaction kinetics for high ... at overpotential of 172 mV and 231 mV towards the hydrogen evolution reaction and oxygen evolution reaction with robust ...
Fowler, Joanna S. (1977). "2-Methyl-3-butyn-2-ol as an acetylene precursor in the Mannich reaction. A new synthesis of suicide ... reactivation and aging kinetics of highly toxic organophosphorus compounds with human and pig acetylcholinesterase". Toxicology ... 5-fluorouracil acts as a suicide inhibitor of thymidylate synthase during the synthesis of thymine from uridine. This reaction ... approach is to create substrates that are unreactive until within that enzymes active site and at the same time being highly ...
Lessons learned include that the use of lifelogging produces highly detailed UX research, but it is very time consuming, due to ... Furthermore, we elaborate a microsphere synthesis protocol allowing accurate control over sphere size, also a critical ... As expected, alginate: collagen microspheres were completely biocompatible and did not cause any adverse reactions when ... the degradation rates of the biomaterial controlling the release kinetics of embedded proangiogenic FGF-2 can be adjusted. ...
This revelation will allow for enhanced control of the 2D MoS2 reaction kinetics allowing for the growth of larger grain and ... 3 slowly decomposed releasing MoO3 precursor for subsequent reaction with the S2 vapor species. This process produced highly ... However, the synthesis of orientated single- or few- layer TMDs with large area remains challenging. The first part of this ... However, the synthesis of orientated single- or few- layer TMDs with large area remains challenging. Here, a facile chemical ...
They feature fast reaction kinetics, great structural diversity, tailorability, and benefit from cost-effective synthesis ... The reaction mechanism of 10a is presented in Fig. 20, and this highly reversible two-electron transfer process offers ... 3.1 Reaction mechanism. In contrast to organic reactions in chemical synthesis, reversibility is essential in battery reactions ... multi-electron transfer reaction, chemical stability, and fast reaction kinetics to meet the requirements of high-performance ...
... the reaction kinetics was further delicately balanced by tuning the reaction temperature, which proved to be critical in ... This synthesis is highly scalable, so that it provides a simple yet very robust process for producing Ag quasi-nanospheres for ... and the reaction time. We find that Ostwald ripening may occur quickly if the spheres are kept in the reaction solution, ... We report a general method for the synthesis of noble metal nanorods, including Au, Ag, Pt, and Pd, based on their seeded ...
... oxidants for the following reactions: acylation / esterification, alkylation / etherification, amide coupling, various cross- ... Discover how SiliaBond can optimize your synthesis! We offer reagents & ... Highly suitable for either batch or continuous flow applications. *Convenient for high throughput medicinal & discovery ... Compares very favourably to polymer-based reagents: no swelling, thermally stable, more easily scalabe, faster kinetics, ...
... the authors treat the use of non-aqueous reaction systems, applications in organic synthesis, bioreactor design and reaction ... Following an introduction to the history of enzyme applications and the motivations for using these highly selective and ... environmentally friendly methods, the book covers enzyme mechanisms and kinetics, production, recovery, characterization and ... Professor Bornscheuers main research interest is the application of enzymes in the synthesis of optically active compounds and ...
  • His research interests include heterogeneous catalysis, catalyst synthesis, and reaction kinetics. (
  • Several different topics (automation, catalysis, green chemistry, scalability, methodological studies and total syntheses) were considered to hold promise for the future advance of chemical sciences in Brazil. (
  • We decided to focus on the most promising areas of academic research which, in our viewpoint, are bound to contribute for the future progress in synthetic chemistry, namely: 1) green chemistry, 2) catalysis, 3) automation and 4) scalability, as well as, 5) the development of new and improvement of known methodologies and applications to the total synthesis of natural products and pharmaceutical ingredients. (
  • A rational design of hybrid systems provides a platform (i) to combine heterogeneous and homogeneous catalysis, which have been explored rather separately, and employ the best of the both fields, (ii) to produce extraordinary or synergystic properties at the interface of different types of materials, (iii) to carry out consecutive reactions in tandem, and (iv) to exploit the flexibility and diversity of organic, inorganic, and metallic materials. (
  • In biochemistry, suicide inhibition, also known as suicide inactivation or mechanism-based inhibition, is an irreversible form of enzyme inhibition that occurs when an enzyme binds a substrate analogue and forms an irreversible complex with it through a covalent bond during the normal catalysis reaction. (
  • The approach is multidisciplinary: synthesis, kinetics, development of novel instrumentation, sophisticated NMR spectroscopy, theory, and computations all are brought to bear on contemporary issues in homogeneous catalysis. (
  • The group is comprised of researchers in inorganic chemistry, materials and chemical engineering working together to solve catalysis problems at the intersection of chemistry and reaction engineering. (
  • Int. Ed. 2010, 49, 2451 - 2460 Angewandte Chemie Reviews A meteoric rise: After their first application in asymmetric conjugate addition reactions in 1996, phosphoramidites have developed into one of the most effective ligands in enantioselective transitionmetal catalysis. (
  • Asymmetric Catalysis J. F. Teichert, B. L. Feringa* 2486 - 2528 Phosphoramidites: Privileged Ligands in Asymmetric Catalysis Communications Going forward in reverse: The configuration of the product of grinding-induced symmetry breaking can be controlled simply by the order in which the different reaction-mixture components are combined (see scheme: I) glass beads, II) racemic mixture (enantiomers differentiated by color), III) solvent, IV) racemization catalyst). (
  • We welcome research that shows new or significantly improved protocols or methodologies in total synthesis, synthetic methodology or physical and theoretical organic chemistry as well as research that shows a significant advance in the organic chemistry or molecular design aspects of chemical biology, catalysis, supramolecular and macromolecular chemistry, theoretical chemistry, mechanism-oriented physical organic chemistry, medicinal chemistry or natural products. (
  • In this overview, we present our analysis of the future of organic synthesis in Brazil, a highly innovative and strategic area of research which underpins our social and economical progress. (
  • Almost 30 years ago, Dieter Seebach attempted to review the important advances in the domain of organic synthesis over the twenty five preceding years and to project the future in this area (Seebach 1990). (
  • The ideas and thoughts put forth in that paper were the subject of much debate over the coming years as some have taken his words as if organic synthesis had matured and stagnation was awaiting ahead. (
  • Recently, Brocksom and coworkers reviewed the important changes that have taken place in the last twenty to thirty years on the directions and objectives of organic synthesis worldwide (Brocksom et al. (
  • 2015), and in this paper we decided to take a bird's-eye view of the scenario of organic synthesis in Brazil while benchmarking it against the most relevant accomplishments worldwide. (
  • Organometallic Synthesis represents a remarkably broad scope of use in synthetic organic chemistry. (
  • Organometallic Synthesis is among the most actively researched areas in chemistry and critically important in the fields of organic, inorganic, biochemical and catalytic chemistry. (
  • There are also research efforts in the use of organometallic reagents in the synthesis of ever-more complex and tailored organic compound, for which organometallic reagents drive specific bonding and/or catalyze reactions. (
  • Hydrometalation is a synthesis method in which a molecule with a metal -hydrogen bond reacts with an organic molecule containing a double bond, forming a organometallic with a metal-carbon bond. (
  • Various addition and elimination reactions form organometallic compounds from metallo-organic molecules. (
  • Organometallic reagents are frequently used to synthesize organic molecules since they drive specific bonding and/or catalyze reactions. (
  • Both organomagnesium and organolithium reagents are strong bases for deprotonation and readily form C-C bonds as well as drive many other organic reactions. (
  • Many synthesis reactions are far more complex than A + B → C. For example, organic synthesis reactions may involve more than two different molecules, and mixtures of products can occur along with unreacted starting materials. (
  • In consideration of advantageous features such as potentially low cost, vast molecular diversity, and highly tailorable properties, organic and organometallic molecules emerge as promising alternative electroactive species for building sustainable RFBs. (
  • Increasingly, the use of heterogeneous reagents in organic synthesis and chemical production is growing in importance. (
  • Alongside the application of soluble and immobilized biocatalysts, including whole-cell systems, the authors treat the use of non-aqueous reaction systems, applications in organic synthesis, bioreactor design and reaction engineering. (
  • If you enjoy pondering or working through organic mechanisms I would suggest buying "The Art of Writing Reasonable Organic Reaction Mechanisms" by Robert Grossman. (
  • This textbook highlights the competing processes and limitations of the most important reactions used in organic synthesis. (
  • The endo addition that occurs in the classical cycloadditions of cyclopentadiene with methyl vinyl ketone and methyl acrylate is more favored when the reaction is carried out in aqueous medium than when it is performed in organic solvents (Table 6.4) [2b, c]. (
  • Inorganic-organic functionalized mesoporous-materials have been shown to have a high activity for a number of liquid phase catalytic reactions in organic solvents. (
  • Organic synthesis, supramolecular chemistry, chemical biology and more. (
  • We welcome important research in all areas of organic synthesis, including studies on small organic molecules and biomolecules, and studies that report purely synthetic work without biological data. (
  • We welcome studies that report important new work in the molecular design of supramolecular or macromolecular compounds or organic materials either with a strong component in organic synthesis or with novel organic structural features. (
  • We welcome articles that report new and interesting syntheses of natural products (see Organic Synthesis guidelines above) or chemical studies of biosynthetic pathways. (
  • DNA-templated organic synthesis enables the translation of DNA sequences into synthetic small-molecule libraries suitable for in vitro selection. (
  • The primary objective of this research was to model and understand the chelate-modified Fenton reaction for the destruction of trichloroethylene (TCE) present in both the aqueous and organic (in the form of droplets) phases. (
  • Assessing the Merits of Homogeneous Reactions in Flask and Flow For the USA and Canada: ANGEWANDTE CHEMIE International Edition (ISSN 1433-7851) is published weekly by Wiley-VCH, PO Box 191161, 69451 Weinheim, Germany. (
  • Existing kinetic models for ampicillin and cephalexin synthesis by PGA do not consider the effects of pH value on the reaction despite the fact that pH is known to affect the enzyme selectivity and activity. (
  • OGG1 is highly specific for the base opposite the lesion, efficiently excising oxoG and cleaving AP sites located opposite to C, but not opposite to A. The activity is also profoundly decreased by amino acid changes that sterically interfere with oxoG binding in the active site of the enzyme after the lesion is everted from the DNA duplex. (
  • Even though vinyl acetate is more reactive and renders the reaction irreversible, the liberated acetaldehyde may inactivate the enzyme, especially lipases fromCandidu rugosa and Geotrichum candidum . (
  • Some of the limitations of tagatose biosynthesis using LAI that may be hindering commercial viability are, (1) unfavorable enzymatic kinetics since galactose is not the native substrate of LAI, (2) low enzyme stability, particularly in the absence of divalent metal ions, and (3) low equilibrium constant for galactose to tagatose isomerization. (
  • Steady-state kinetics measurements involve monitoring the absorbance or fluorescence change exhibited by an enzyme/substrate complex at constant concentration throughout the measurement. (
  • Pre-steady state kinetics involve measuring of the formation of the enzyme/substrate complex. (
  • The Olis CLARiTY chamber offers an exciting new possibility of measuring enzyme kinetics in highly scattering environments such as those in whole cell or mitochondria suspensions. (
  • Taken together, these results establish the use of DNA-templated synthesis and in vitro selection to discover small molecules that modulate enzyme activities, and also reveal a new scaffold for selective ATP-competitive kinase inhibition. (
  • These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. (
  • The major points made by Seebach were that function, more than the structure of molecules, would lead the synthetic efforts and that novel reactions would most likely come from biological and organometallic chemistry, shifting the attention to catalytic and asymmetric methodologies, and these points appear to be, to a large extent, confirmed. (
  • Synthetic chemistry is a highly creative discipline due to its ability to create its object of investigation, to invent new methodologies as well to contribute to fundamental and applied knowledge, underpinning our social and economical progress with the discovery of new drugs, contributing to food supply, providing new polymers and materials with novel properties and functions with a direct impact on the welfare of the world population. (
  • This general type of reaction is perhaps the most common in chemistry. (
  • Synthetic chemistry depends on reliable, high-yielding and selective reactions that access a wide variety of different structures. (
  • We have shown that this chemistry is applicable to the synthesis of the core ring system of the alkaloid manzamine A, which has significant biological activity (anti-cancer, anti-malarial, and other activity). (
  • This chemistry provides an efficient method to prepare three rings directly from an acyclic aldehyde in a stereocontrolled way and has been applied to the total syntheses of several alkaloids (such as aspidospermidine, aspidospermine, quebrachamine and myrioxazine A). (
  • Choi A & Coldham I (2019) Three-component couplings for the synthesis of pyrroloquinoxalinones by azomethine ylide 1,3-dipolar cycloaddition chemistry . (
  • Effect of Medium on the Kinetics of Stereoselective Synthesis of a Highly Functionalized Cyclopropanesame', Physical Chemistry Research , 8(1), pp. 19-30. (
  • This research, reported Dec. 2 in Nature Chemistry , promises to advance scientists' understanding of processes central to the pharmaceutical, metallurgical, cement and mineral industries - and could open new opportunities in "green chemistry" and environmentally friendly chemical synthesis. (
  • When we set out to study these reactions, the challenge was to observe the entire reaction without disturbing it, in particular the short-lived intermediates that appear and disappear under continuous impact in less than a minute", says Friščić, an assistant professor in McGill's Department of Chemistry. (
  • Science 10 introduces students to the following concepts: Ecology (biomes and energy transfers), Earth Science (plate tectonics and weather), Chemistry (reactions and radioactivity) and Physics (motion/kinematics). (
  • F. Zaragoza Dörwald studied chemistry at the Georg-August University of Göttingen and Université Louis Pasteur, Strasbourg, where he obtained his Ph.D. in 1990 on the synthesis of natural products under the guidance of M. Franck-Neumann and M. Miesch. (
  • Accordingly, click chemistry, characterized by fast, clean and high yielding reactions represents an effective tool for the modification of polymers. (
  • We also seek to understand the fundamental chemistry and reaction pathways occurring under reaction conditions. (
  • The authors were selected in order to provide insight into a broad range of topics, including small molecule synthesis, polymer degradation, computational chemistry as well as highly detailed experimental work in the solid, liquid, and gaseous states. (
  • A pseudo-first-order reaction kinetics was observed for the RAFT polymerization of PDMAEMA at a low conversion. (
  • By controlling the aminolysis reaction of PLA and RAFT polymerization degree of DMAEMA, the length distributions of the PLA and PDMAEMA blocks can be controlled. (
  • To achieve this goal, an efficient methodology is created to incorporate a highly reactive strained alkyne functional group as a modification site to expand the post polymerization modification of polymers. (
  • Thus, the iii liberation of the strained alkyne and the subsequent reaction with a variety of azide reaction partners provides a robust route towards post-polymerization modification of polymers and generating a library of polymers. (
  • however, it can also undergo undesirable side reactions and thus we also incorporated a masking strategy so the strained alkyne will not interfere with the polymerization process and only react when needed. (
  • 2. Preparation of functional Poly(methylstyrene) latex particles in an emulsifier - free emulsion system Highly monodisperse emulsifier-free PMS latex particles were prepared via an emulsifier-free emulsion polymerization, using 2,2'-azobis-(2-amidineopropane) dihydrochloride (V-50) as an initiator. (
  • The kinetics of the polymerization was studied and effects of initiator concentration, ionic strength in the aqueous phase, and polymerization temperature on the polymerization reaction are examined. (
  • ReactIR in situ analytics minimizes exposure of scientists and technicians to toxic chemicals and potentially hazardous reactions by eliminating grab sampling for offline analysis. (
  • The application of in situ Raman spectroscopy and synchrotron X-ray powder diffraction to monitor the reaction of urea phosphate and either calcium hydroxide or carbonate enabled the first quantitative and in situ study of a mechanochemical system in which one of the products of a chemical reaction (water) mediates the rate of transformation and underpins positive feedback kinetics. (
  • Zhao J, Wang X, Sun T, Li L (2005) In situ templated synthesis of anatase single-crystal nanotube arrays. (
  • Here, the method is used to make aqueously soluble TiO 2 NPs from their titanium salt and lithium oxide in the presence of some amphiphilic capping ligands, i.e., gallic acid and dopamine, where the surface functionalization of the TiO 2 NPs is made in situ (within the synthesis mixture) so as to define NP dimension and dispersivity. (
  • This is not meant to be a review paper on the academic research nor a comprehensive coverage of all areas of research underway in the area of chemical synthesis in Brazil. (
  • The use of microwave (MW) energy, which was initially applied in inorganic chemical synthesis in these same solid-state ceramic routes, allows a significant reduction of the reaction times. (
  • Synthesis reactions are one of the major classes of chemical reactions, which include single displacement, double displacement, and combustion reactions. (
  • EasyMax chemical synthesis reactor provides automated parameter control, accuracy, and precision of reaction parameters. (
  • Using the mechanosynthesis of the calcium urea phosphate fertilizer cocrystal as a model, we provide a quantitative investigation of chemical autocatalysis in a mechanochemical reaction. (
  • His prize-winning work focused on the role of frontier orbitals in chemical reactions: specifically that molecules share loosely bonded electrons which occupy the frontier orbitals, that is the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO). (
  • Fukui had acknowledged in his Nobel lecture that, 'It is only after the remarkable appearance of the brilliant work by Woodward and Hoffmann that I have become fully aware that not only the density distribution but also the nodal property of the particular orbitals have significance in such a wide variety of chemical reactions. (
  • Chemical modifications of mRNA may regulate many aspects of mRNA processing and protein synthesis. (
  • Our current and prior findings highlight how chemical modifications of mRNA tune the dynamics of protein synthesis at different steps of translation elongation. (
  • Our approach brings together a quantum-chemical analysis of the reaction pathway, a microkinetic model of the reaction dynamics, and a continuum model for mass transport of all species through the electrolyte. (
  • In this final installment of our Chemical Kinetics series , we will look at one of the major chemical syntheses of the modern era. (
  • From here, we will ignore the good and bad of producing ammonia, and move straight to considering the chemical engineering involved by simulating ammonia synthesis with COMSOL Multiphysics. (
  • In recent years, ball milling has become increasingly popular in the production of highly complex chemical structures. (
  • In principle, this technique could be used to study all types of chemical reactions in a ball mill, and optimize them for processing in a range of industries. (
  • Metabolism Refers to the sum total of all chemical reactions that take place in an organism. (
  • ATP is used to power the anabolic Reactions that require chemical energy. (
  • If an endergonic process requires less free energy than an exergonic process produces, coupling those two reactions allows for maximum efficiency, and an overall negative delta G. The Reaction Profile All reactions require an input of energy (the 'activation energy') to make the breaking of current chemical bonds energetically favorable (the 'transition state' - unstable). (
  • Most syntheses in the chemical research laboratory fail and usually require several attempts before proceeding satisfactorily. (
  • The McFarland group couples fundamental processes at surfaces with novel material systems to facilitate reactions related to the production and utilization of chemical fuels. (
  • Their group develops and uses automated, high-throughput, synthesis and screening systems combining traditional chemical approaches to combinatorial methods for new material and material system discovery and optimization. (
  • In 2009, he was to Canada to be up a book kinetics of ion molecule reactions in the Department of Chemical and Materials Engineering at the University of Alberta, where he is the Nexen Professor of Catalytic Reaction Engineering. (
  • The chapters cover fundamental topics, from photocatalyst materials, surface-modified materials, reaction kinetics and reactor modelling, to translational research activities on chemical synthesis, energy conversion and water treatment. (
  • The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transport of substances into and between different cells, in which case the set of reactions within the cells is called intermediary metabolism or intermediate metabolism. (
  • The chemical reactions of metabolism are organized into metabolic pathways, in which one chemical is transformed through a series of steps into another chemical, by a sequence of enzymes. (
  • Many proteins are enzymes that catalyze the chemical reactions in metabolism. (
  • Through data-rich experiments, ReactIR simplifies and speeds the measurement of kinetic factors in synthesis reactions. (
  • Highly selective palladium catalyzed kinetic resolution and enantioselective substitution of racemic allylic carbonates with sulfur nucleophiles: asymmetric synthesis of allylic sulfides, allylic sulfones, and allylic alcohols. (
  • We describe the highly selective palladium catalyzed kinetic resolutions of the racemic cyclic allylic carbonates rac-1 a-c and racemic acyclic allylic carbonates rac-3 aa and rac-3 ba through reaction with tert-butylsulfinate, tolylsulfinate, phenylsulfinate anions and 2-pyrimidinethiol by using N,N'-(1R,2R)-1,2-cyclohexanediylbis[2-(diphenylphosphino)-benzamide] (BPA) as ligand. (
  • Furthermore the course of the asymmetric Torgov cyclisation and the disulfonimide (DSI) catalyzed synthesis of β3-amino esters from N-Boc amino sulfones were investigated by kinetic NMR-measurements and the underlying mechanistic models were confirmed by the experimental results. (
  • A model comprising a set of two kinetic equations was used to describe the hydrolysis and condensation reactions of glucoamylase-catalyzed reactions, even to highly concentrated systems. (
  • To investigate the potential of this synthesis with beta-glycosidase from Pyrococcus furiosus we determined kinetic parameters for substrate conversion and product formation from cellobiose, lactose, glucose and galactose. (
  • Kinetic studies were carried out by varying the substrates concentration at the determined reaction conditions. (
  • Methanol was optimized as a desirable solvent in the synthesis of piperidine, nevertheless, ethanol in a kinetic investigation had none effect on the enhancement of the reaction rate than methanol. (
  • 4 Enzymatic synthesis of β-lactam antibiotics can help to mitigate these risks by operating in mild aqueous conditions. (
  • Douglas, D. J. Pre-Steady-State Kinetics Of Enzymatic Reactions Studied By Electrospray Mass Spectrometry With On-Line Rapid-Mixing Techniques . (
  • Using the bacteriophage T7 and E.coli replication machineries as model systems (in collaboration with Charles Richardson & Nick Dixon), we study how the different enzymatic activities at the replication fork (DNA unwinding, synthesis, priming) are orchestrated. (
  • Although the reactivity of the strained alkyne is desirable, it can be susceptible to side reactivity due to the highly reactive carbon-carbon triple bond. (
  • The functional group of choice for my project was a strained alkyne, which is a highly reactive group allowing for fast and efficient reactivity. (
  • These conditions do not permit a subtle control of the reaction stoichiometry nor is it possible to synthesize thermally labile or metastable compounds [ 2 ]. (
  • In the simplest sense, Organometallic Synthesis refers to the process of creating organometallic compounds. (
  • This arises from the use of organometallic reagents in the synthesis of an enormous number of commercially important compounds, widely used in the pharmaceutical, polymer, and petrochemical industries. (
  • The large array of elements that can form organometallic compounds result in vast research in procedures for organometallic synthesis. (
  • Hydrogenation and hydroformylation reactions are all industrially important reactions that are catalyzed by various organorhodium or organocobalt compounds. (
  • The discovery of new methods in synthesis is crucial to expand the range of novel compounds that can be made easily. (
  • Areas of concentration within cellular biology will include a focus on: cell structure, biological compounds and molecules, DNA and protein synthesis. (
  • The main limitation of solid-state syntheses, with respect to those exploiting molecular precursors ( i.e. , those occurring in the liquid or gaseous phases), is the difficulty in bringing the different reactants sufficiently close to each other to allow optimum reduction of diffusion paths. (
  • By optimizing reaction variables, ReactIR with EasyMax aid impurity reduction. (
  • Benefiting from this unique synthesis strategy, the obtained photocatalysts show superior activity to conventionally prepared photocatalysts in dye decomposition and water-reduction hydrogen production under visible-light illumination. (
  • Moreover, cathode polarization can influence the kinetics of CO 2 reduction. (
  • An attractive strategy to this end involves the electrochemical production of CO by the CO 2 reduction reaction (CO 2 RR) and the production of H 2 by the hydrogen evolution reaction (HER). (
  • Up-to-date, oxygen reduction reaction (ORR) is one of the main hindering factors for the commercialization of LTFCs, because of its slow kinetics and high overpotential, causing major voltage loss and short-term stability. (
  • We report a NaOH-mediated NaBH 4 reduction method for the synthesis of mono-, bi-, and tri-thiolate-protected Au 25 nanoclusters (NCs) with precise control of both the Au core and thiolate ligand surface. (
  • The key strategy is to use NaOH to tune the formation kinetics of Au NCs, i.e., reduce the reduction ability of NaBH 4 and accelerate the etching ability of free thiolate ligands, leading to a well-balanced reversible reaction for rapid formation of thermodynamically favorable Au 25 NCs. (
  • A novel NaOH-mediated NaBH 4 reduction method was developed for the synthesis of mono-, bi-, and tri-thiolate-protected Au 25 nanoclusters. (
  • It consists of two half-reactions - the oxidative O2 evolving reaction and reduction of protons generating H2. (
  • Three classes of sonochemical reactions exist: homogeneous sonochemistry of liquids, heterogeneous sonochemistry of liquid-liquid or solid-liquid systems, and, overlapping with the aforementioned, sonocatalysis. (
  • PGA also hydrolyzes the highly soluble PGME into phenylglycine (termed primary hydrolysis). (
  • OGG1 catalyzes two successive reactions - N-glycosidic bond hydrolysis (glycosylase activity) and DNA strand cleavage on the 3'-side of the lesion by ß-elimination (lyase activity). (
  • Among them, the solution-based sol-gel synthetic route is the most widely used approach and consists of two continuous steps: solvolytic reaction (usually hydrolysis) of a titanium salt and a further condensation reaction. (
  • In the second half-reaction, this protein subunit then catalyzes transfer of the amino acid portion of the adenylate to the RNA subunit of the particle. (
  • He spent each one postdoctoral year in the groups of A. Pfaltz (University of Basel) and A.P. Marchand (University of North Texas), and worked then on the synthesis of unnatural amino acids at the Technical University of Dresden. (
  • Oxidative kinetics of amino acids by peroxydisulphate: effect of dielectric constant. (
  • A key element of our strategy is to synthesize well-defined molecular precursors and anchor them onto solid supports via self-limiting surface reactions. (
  • Before the era of industrial ammonia synthesis, these precursors were usually imported from countries rich in guano (bird and bat droppings). (
  • In contrast, the hydrophobicity and cumbersome synthesis of the cyclooctyne precursors in the strain-promoted azide-alkyne cycloaddition (SPAAC) have proven limiting to their widespread application. (
  • 99 % ee) with 2-pyrimidinethiol in the presence of BPA was shown to exhibit, under the conditions used, an overall pseudo-zero order kinetics in regard to the allylic substrate. (
  • Based on the spectral data, the overall order of the reaction followed the second order kinetics. (
  • Continuous flow processes are rapidly becoming more frequently used, and ReactIR technology accomodates the real-time analysis of continuous flow and batch syntheses. (
  • Often, multiple competing processes, including reaction kinetics, mass transfer, and microstructural evolution, are lumped together into a single rate expression that limits the ability to translate this information to different conditions. (
  • Life is Highly Ordered Life Requires Energy Input Organisms use the energy they convert to power cellular/organismal processes that decrease their overall entropy (or at least delay its increase). (
  • The basic processes of electrochemistry and photocatalysis for hydrogen production are described along with photocatalytic reactions and semiconductor photocatalysts, particularly metal oxides. (
  • Benefiting from both structural and compositional characteristics, the resulting NiS2/FeS2/NC nanorods possess abundant active sites, high electrical conductivity and rapid mass transfer, thereby delivering 10 and 20 mA cm(-2) at overpotential of 172 mV and 231 mV towards the hydrogen evolution reaction and oxygen evolution reaction with robust stability in 1.0 M KOH solution, respectively. (
  • Developing highly efficient transition metal dichalcogenide electrocatalysts would be significantly beneficial for the electrocatalytic hydrogen evolution reaction (HER) from water splitting. (
  • Over the last years a wide range of organocatalysts were developed enabling highly diverse transformations with high enantioselectivities and excellent yields. (
  • We aim to understand the interactions and transformations of molecules in solution and at gas-solid interfaces by creating highly uniform active sites. (
  • Now, for the first time, scientists have studied a milling reaction in real time, using highly penetrating X-rays to observe the surprisingly rapid transformations as the mill mixed, ground, and transformed simple ingredients into a complex product. (
  • The overarching goal is to understand the interactions and transformations of molecules in solution and at gas-solid interfaces by creating highly uniform, grafted active sites. (
  • While a substantial body of literature exists on nuclear graphite oxidation in the presence of molecular oxygen and significant efforts have been made to characterize oxidation kinetics of various grades, the value of existing information is somewhat limited. (
  • Glutathione synthesis was also increased, presumably in response to oxidative stress. (
  • The data fusion of metabolomic and transcriptomic changes proved to be a highly sensitive approach for monitoring early stage changes in altered hepatic metabolism, oxidative stress and cytochrome P450 induction simultaneously. (
  • Methanol oxidation reaction(MOR)is of great technological interest because of its potential application to direct methanol fuel cells(DMFCs),which show great potential as high-efficiency, low-emission future power source. (
  • Yuan, C. Oxidation behavior and kinetics of light, medium, and heavy crude oils characterized by thermogravimetry coupled with fourier transform infrared spectroscopy [Text] / C. Yuan, D.A. Emelianov, M.A. Varfolomeev // Energy & Fuels. (
  • Laboratory experiments explore inorganic synthesis, molecular structure and properties, and spectroscopy, with an emphasis on laboratory safety, computerized data acquisition and analysis, and the theory of analytical instrumentation. (
  • The role of the carbene as intermediate for several, mostly unwanted, side reactions was determined by OPSY-EXSY-experiments and extensive DFT calculations. (
  • One of the strangest aspects of energy transfer experiments is that when the donor (D) and acceptor (A) dyes are confined to small domains, the overall kinetics of ET become sensitive to the size and shape of the confining space. (
  • These 'molecular movies' will allow us to dissect the reaction kinetics at a level of detail inaccessible to conventional ensemble experiments. (
  • This article reviews the reaction of graphite with molecular oxygen in terms of the reaction kinetics, gas transport, and microstructural evolution of graphite. (
  • It also presents the foundations of a model for the graphite-molecular oxygen reaction system that is kinetically independent of graphite grade, and is capable of describing both the bulk and local oxidation rates under a wide range of conditions applicable to air-ingress. (
  • Interestingly enough, after building this reaction using a molecular model kit it made a lot more sense in 3d, especially for the double bond reformation. (
  • Water is the only by-product and can be removed by adding molecular sieve in the reaction mixture. (
  • K. Hult and M. Holmquist , Kinetics, Molecular Modeling, and Synthetic Applications with Microbial Lipases. (
  • Many structural and biochemical studies have contributed towards an understanding of the molecular workings of the viral proteins that mediate fusion, but little is known about the dynamics of the conformational changes and the nature of the potential cooperativity that are needed to catalyze the kinetically highly unfavorable fusion process. (
  • For many years, the most widely used method for the preparation of oxides, chalcogenides, silicides and carbides was the direct solid-state reaction between powders, and it probably still represents the most widespread approach for the large-scale production of these important inorganic materials [ 1 , 2 ]. (
  • Examples of this type of synthesis are two of the most frequently used organometallic reagents, organolithium and organomagnesium, for which the metal is reacted with an alkyl- or aryl-halide to form the desired reagent. (
  • In double-decomposition reactions , metal halides exchange with alkylating reagents to yield the organometallic reagent. (
  • Compares very favourably to polymer-based reagents: no swelling, thermally stable, more easily scalabe, faster kinetics, compatible with all solvents and mechanically stable. (
  • In devising synthetic methodologies to engineered nanomaterials, hydrothermal synthesis and solution combustion synthesis can be used as reference systems to illustrate effects related to microwave irradiation. (
  • In the second case, strong exothermic combustion syntheses can benefit from the application of microwaves to convey energy to the reaction not only during the ignition step, but also while it is occurring and even after its completion. (
  • Synthesis reactions are reactions that occur when two different atoms or molecules interact to form a different molecule or compound. (
  • When two or more reactants combine to form a more complex molecule, the composition of the final reaction mixture is dependent on the conditions at which the reaction is carried out. (
  • Here, using single-molecule, bulk kinetics and structural methods, we show that 2'-O-methylation within coding regions of mRNA disrupts key steps in codon reading during cognate tRNA selection. (
  • The Return of Kinetics Adenosine Tri-Phosphate The short term energy storage/release molecule of choice in cells tens of millions made and used per second per cell The bonds between phosphate groups in nucleoside tri-phosphates (like ATP) are relatively unstable. (
  • We will Get you now all as the book kinetics of ion molecule reactions reveals still in our specification. (
  • Click here for a complete course catalog other companies infected rather frequently meet centuries to encourage their book kinetics of ion molecule screens and online construction scores. (
  • This were to appear around 16 500 book kinetics of ion molecule options around the distribution, through narrowband companies and cite knowledgeable. (
  • Most back, these only primary parents established from the book kinetics of ion molecule reactions from 1950. (
  • preferred for including book kinetics of ion molecule subject-matter use and not Editorial sites immune as helpla and content. (
  • Research in the HTE project involves development of new fabrication systems for combinatorial synthesis of alloys, automated tools for optical and electrochemical activity screening, and information systems for storage and analysis of data. (
  • The frontier orbitals concept came to be recognized following the 1965 publication by Robert B. Woodward and Roald Hoffmann of the Woodward-Hoffmann stereoselection rules, which could predict the reaction rates between two reactants. (
  • The relationship between the energy of the products and the energy of the reactants is what determines if a reaction is exergonic or endergonic. (
  • Labor-saving preparation of highly active electrocatalysts for alcohols oxidation, especially for the ethylene glycol and glycerol electrooxidation is of great importance for the development of fuel cells. (
  • As these molecules are vital for life, metabolic reactions either focus on making these molecules during the construction of cells and tissues, or by breaking them down and using them as a source of energy, by their digestion. (
  • Free energies of activation for all elementary reactions are determined from density functional theory calculations. (