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8-hydroxyquinoline
8-Hydroxyquinoline (also known as oxine) is a chelate, chelating agent which has been used for the Quantitative analysis (chemistry), quantitative determination of metal ions. In aqueous solution 8-hydroxyquinoline has a pKa value of ca. 9.9 It reacts with metal ions, losing the proton and forming 8-hydroxyquinolinato-chelate complexes. The aluminium complex is a common component of organic light-emitting diodes (OLEDs). Variations in the substituents on the quinoline rings affect its luminescence properties. In the photochemically induced excited-state zwitterionic isomers are formed in which the hydrogen atom is transferred from oxygen to nitrogen. The complexes as well as the heterocycle itself exhibit antiseptic, disinfectant, and pesticide properties, functioning as a transcription inhibitor. Its solution in alcohol is used in liquid bandages. It once was of interest as an anti-cancer drug. A thiol analogue, 8-Mercaptoquinoline, 8-mercaptoquinoline is also known. The r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trace Metal Detection Test
The trace metal detection test or technique was developed during the Vietnam War in the 1960s to identify people who may have been carrying firearms against their skin. A 0.2% solution of 8-hydroxyquinoline in isopropanol sprayed on the skin and illuminated with shortwave ultraviolet (UV) light after several minutes reveals a pattern and type of metal based on trace amounts of metal transferred to the skin that are invisible under normal lighting. The technique was later adopted by police in the United States to help determine if a person had carried a firearm. In a California crime an automatic handgun carried in the waistband of a criminal reportedly produced an impression of the weapon's serial number. Presence and persistence of a detectable residue depends primarily on the amount of perspiration, length of contact, and time since exposure. A few minutes of exposure can leave detectable residue and the result can remain for up to forty-eight hours. Preservation of the results is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionophore
In chemistry, an ionophore () is a chemical species that reversibly binds ions. Many ionophores are lipid-soluble entities that transport ions across the cell membrane. Ionophores catalyze ion transport across hydrophobic membranes, such as liquid polymeric membranes (carrier-based ion selective electrodes) or lipid bilayers found in the living cells or synthetic vesicles ( liposomes). Structurally, an ionophore contains a hydrophilic center and a hydrophobic portion that interacts with the membrane. Some ionophores are synthesized by microorganisms to import ions into their cells. Synthetic ion carriers have also been prepared. Ionophores selective for cations and anions have found many applications in analysis. These compounds have also shown to have various biological effects and a synergistic effect when combined with the ion they bind. Classification Biological activities of metal ion-binding compounds can be changed in response to the increment of the metal concentra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
8-Mercaptoquinoline
8-Mercaptoquinoline is the organosulfur compound with the formula C9H7NSH. It is a derivative of the heterocycle quinoline, substituted in the 8-position with a thiol group. The compound is an analog of 8-hydroxyquinoline, a common chelating agent. The compound is a colorless solid. Preparation Quinoline reacts with chlorosulfuric acid to form quinoline-8-sulfonyl chloride, which reacts with triphenylphosphine in toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) ... to form 8-mercaptoquinoline. :: References {{DEFAULTSORT:Mercaptoquinoline, 8- Thiols Quinolines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuse Knapweed
''Centaurea diffusa'', also known as diffuse knapweed, white knapweed or tumble knapweed, is a member of the genus ''Centaurea'' in the family Asteraceae. This species is common throughout western North America but is not actually native to the North American continent, but to the eastern Mediterranean. Description Diffuse knapweed is an annual or biennial plant, generally growing to between 10 and 60 cm in height. It has a highly branched stem and a large taproot, as well as a basal rosette of leaves with smaller leaves alternating on the upright stems. Flowers are usually white or pink and grow out of urn-shaped heads carried at the tips of the many branches. Diffuse knapweed often assumes a short rosette form for one year, reaching maximum size, then rapidly growing and flowering during the second year. A single plant can produce approximately 18,000 seeds. Synonyms * ''Centaurea microcalathina'' Tarassov * ''Centaurea cycladum'' Heldr. * ''Centaurea parviflora'' Sib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PBT2
PBT2 is a safe-for-human-use Zinc ionophore and an experimental drug candidate. It is a second-generation 8-hydroxyquinoline analog intended to be a successor to clioquinol and a potential treatment of Alzheimer's disease and Huntington's disease. Clinical trials PBT2 was the subject of three phase II clinical trials for Alzheimer's disease ('EURO'), 'IMAGINE' & 'IMAGINE EXTENSION') and one for Huntington's disease ('REACH2HD') trial. The cognition efficacy results for Alzheimer's disease were mixed. The EURO trial showed some improvements in cognitive functions, in particular executive function domains, while the IMAGINE study did not."Prana Biotech Plunges 76%; Drug Fails in Alzheimer Study""PBT2 Takes a Dive in Phase 2 Alzheimer's Trial" Although there is no evidence that PBT2 is of any benefit in Alzheimer's dementia,''"There is no evidence that MPACs (PBT1 or PBT2) are of benefit in Alzheimer's dementia"'' the number of subjects treated with PBT2 for AD in Phase II pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clioquinol
Clioquinol (iodochlorhydroxyquin) is an antifungal drug and antiprotozoal drug. It is neurotoxic in large doses. It is a member of a family of drugs called hydroxyquinolines which inhibit certain enzymes related to DNA replication. The drugs have been found to have activity against both viral and protozoal infections. Antiprotozoal use A 1964 report described the use of clioquinol in both the treatment and prevention of shigella infection and ''Entamoeba histolytica'' infection in institutionalized individuals at Sonoma State Hospital in California. The report indicates 4000 individuals were treated over a 4-year period with few side effects. Several recently reported journal articles describing its use as an antiprotozoal include: * A 2005 reference to its use in treating a Dutch family for ''Entamoeba histolytica'' infection. * A 2004 reference to its use in the Netherlands in the treatment of ''Dientamoeba fragilis'' infection. * A 1979 reference to the use in Zaire in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription Inhibitor
Transcription is the process of copying a segment of DNA into RNA. The segments of DNA transcribed into RNA molecules that can encode proteins are said to produce messenger RNA (mRNA). Other segments of DNA are copied into RNA molecules called non-coding RNAs (ncRNAs). mRNA comprises only 1–3% of total RNA samples. Less than 2% of the human genome can be transcribed into mRNA ( Human genome#Coding vs. noncoding DNA), while at least 80% of mammalian genomic DNA can be actively transcribed (in one or more types of cells), with the majority of this 80% considered to be ncRNA. Both DNA and RNA are nucleic acids, which use base pairs of nucleotides as a complementary language. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript. Transcription proceeds in the following general steps: # RNA polymerase, together with one or more general transcription factors, binds to promoter DNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
QUPIC
PB-22 (QUPIC, SGT-21 or 1-pentyl-1''H''-indole-3-carboxylic acid 8-quinolinyl ester) is a designer drug offered by online vendors as a cannabimimetic agent, and detected being sold in synthetic cannabis products in Japan in 2013. PB-22 represents a structurally unique synthetic cannabinoid chemotype, since it contains an ester linker at the indole 3-position, rather than the precedented ketone of JWH-018 and its analogs, or the amide of APICA and its analogs. PB-22 has an EC50 of 5.1 nM for human CB1 receptors, and 37 nM for human CB2 receptors. PB-22 produces bradycardia and hypothermia in rats at doses of 0.3–3 mg/kg, suggesting potent cannabinoid-like activity. The magnitude and duration of hypothermia induced in rats by PB-22 was notably greater than JWH-018, AM-2201, UR-144, XLR-11, APICA, or STS-135, with a reduction of body temperature still observable six hours after dosing. One clinical toxicology study found PB-22 to be the cause of seizures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Co-evolution
In biology, coevolution occurs when two or more species reciprocally affect each other's evolution through the process of natural selection. The term sometimes is used for two traits in the same species affecting each other's evolution, as well as gene-culture coevolution. Charles Darwin mentioned evolutionary interactions between flowering plants and insects in ''On the Origin of Species'' (1859). Although he did not use the word coevolution, he suggested how plants and insects could evolve through reciprocal evolutionary changes. Naturalists in the late 1800s studied other examples of how interactions among species could result in reciprocal evolutionary change. Beginning in the 1940s, plant pathologists developed breeding programs that were examples of human-induced coevolution. Development of new crop plant varieties that were resistant to some diseases favored rapid evolution in pathogen populations to overcome those plant defenses. That, in turn, required the development o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zwitterion
In chemistry, a zwitterion ( ; ), also called an inner salt or dipolar ion, is a molecule that contains an equal number of positively- and negatively-charged functional groups. : With amino acids, for example, in solution a chemical equilibrium will be established between the "parent" molecule and the zwitterion. Betaines are zwitterions that cannot isomerize to an all-neutral form, such as when the positive charge is located on a quaternary ammonium group. Similarly, a molecule containing a phosphonium group and a carboxylate group cannot isomerize. Amino acids The equilibrium is established in two stages. In the first stage, a proton is transferred from the carboxyl group to a water molecule: :H2N(R)CO2H + H2O H2N(R)CO2- + H3O+ In the second stage, a proton is transferred from the hydronium ion to the amine group: :H2N(R)CO2- + H3O+ H3N+ (R)CO2- + H2O Overall, the reaction is an isomerization reaction :H2N(R)CO2H H3N+ (R)CO2- The ratio of the concentrations of the two sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chelate
Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are called chelants, chelators, chelating agents, or sequestering agents. They are usually organic compounds, but this is not a necessity, as in the case of zinc and its use as a maintenance therapy to prevent the absorption of copper in people with Wilson's disease. Chelation is useful in applications such as providing nutritional supplements, in chelation therapy to remove toxic metals from the body, as contrast agents in MRI scanning, in manufacturing using homogeneous catalysts, in chemical water treatment to assist in the removal of metals, and in fertilizers. Chelate effect The chelate effect is the greater affinity of chelating ligands for a metal ion than that of similar nonchelating (monodentate) ligands for the same metal. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
