Search results for "Organic Chemicals"
showing 10 items of 728 documents
MONENSIN ENHANCES DIGOXIN-INDUCED ARRHYTHMIAS IN GUINEA-PIGS
1993
Effects of pretreatment with monensin (150 ug/kg), atenolol (0.3 mg/kg), atenolol plus monensin, verapamil (0.38 mg/kg), verapamil plus monensin, glibenclamide(0.38 mg/kg) and glibenclamide plus monensin on the dose of digoxin required to induce premature ventricular contractions (PVCS) in anaesthetized guinea-pigs were studied. Monensin reduced while atenolol increased the dose of digoxin required to produce PVCS. Atenolol plus monensin increased the dose of digoxin required to produce PVCS in presence of monensin alone. Verapamil reduces the arrhythmogenic effect of monensin on digoxin. Glibenclamide antagonises the effect of monensin on digoxin induced PVCS. From the present data it coul…
3,4′,5,5′-Tetramethoxy-2′-methylbiphenyl-4-ol
2019
The asymmetric unit of the title compound, C17H20O5, contains two independent molecules, A and B, with similar geometries [dihedral angles between the phenyl rings = 56.19 (8) and 54.98 (7)°, respectively]. Intramolecular O—H...O hydrogen bonds occur in both molecules. In the crystal, the A molecules form [1\overline{1}0] chains linked by O—H...O hydrogen bonds from the hydroxyl group to one of the methoxy O atoms. The B molecules form O—H...O hydrogen bonds to the hydroxyl O atoms of the A molecules and thus act as fixed spacers between the chains of molecule A. Some weak C—H...O contacts are also present.
Predicting the activity of single isolated Lewis acid sites in solid catalysts.
2006
An experimental study of the activity of Ti-, Zr- and Sn-beta catalysts in different types of oxidation reactions is combined with a quantum-chemical analysis of the electronic properties of the active sites and the adsorbed reactants. The differences observed in the catalytic behaviour of the three materials are explained in terms of the molecular orbital distribution of each system. The intrinsic Lewis acid strength of the isolated active site, the degree of back-donation from the catalyst to the empty orbitals of the organic reactant and the net atomic charges on selected atoms are proposed as predictors of reactivity.
Globins and hypoxia adaptation in the goldfish, Carassius auratus
2008
Goldfish (Carassius auratus) may survive in aquatic environments with low oxygen partial pressures. We investigated the contribution of respiratory proteins to hypoxia tolerance in C. auratus. We determined the complete coding sequence of hemoglobin α and β and myoglobin, as well as partial cDNAs from neuroglobin and cytoglobin. Like the common carp (Cyprinus carpio), C. auratus possesses two paralogous myoglobin genes that duplicated within the cyprinid lineage. Myoglobin is also expressed in nonmuscle tissues. By means of quantitative real-time RT-PCR, we determined the changes in mRNA levels of hemoglobin, myoglobin, neuroglobin and cytoglobin in goldfish exposed to prolonged hypoxia (48…
Organic solvent-soluble contents of nickel and cobalt in some algae
1990
In pursuit of our work on metal contents of lipid fractions isolated from plant material, we now show by means of highly sensitive analytical methods that nickel and cobalt are also present in organic extracts of algae in detectable amounts
Impact of α,β-dehydroamino acid residues on the binding abilities of di-, tri- and tetra-peptides
2000
Insertion of a dehydroamino acid residue into a sequence of di-, tri- or tetra-peptide changed considerably the binding abilities of peptide ligands towards copper(II) ions. Potentiometric and spectroscopic (EPR, UV-VIS and CD) data have shown that the amide nitrogen of the dehydroamino acid residue is more effective in co-ordination than its parent analogue. In the case of the bulky ΔPhe residue also the (Z–E) isomerisation has a critical impact on the co-ordination equilibria in the system studied.
THE OCCURRENCE OF CHROMIUM IN RAW MATERIALS AND ITS FATE IN THE BREWING PROCESS
1987
The chromium content of raw materials, intermediate and final products in the brewing process were determined in order to evaluate the contribution of raw materials to the chromium content of beer. The contribution due to beer in the diet is considered in the light of the recommended daily intake of chromium.
IP 3 signalling regulates exogenous RNA i in C aenorhabditis elegans
2015
RNA interference (RNAi) is a widespread and widely exploited phenomenon. Here, we show that changing inositol 1,4,5-trisphosphate (IP3) signalling alters RNAi sensitivity in Caenorhabditis elegans. Reducing IP3 signalling enhances sensitivity to RNAi in a broad range of genes and tissues. Conversely up-regulating IP3 signalling decreases sensitivity. Tissue-specific rescue experiments suggest IP3 functions in the intestine. We also exploit IP3 signalling mutants to further enhance the sensitivity of RNAi hypersensitive strains. These results demonstrate that conserved cell signalling pathways can modify RNAi responses, implying that RNAi responses may be influenced by an animal's physiology…
Halogen bonding and host–guest chemistry between N-alkylammonium resorcinarene halides, diiodoperfluorobutane and neutral guests
2019
Single crystal X-ray structures of halogen-bonded assemblies formed between host N-hexylammonium resorcinarene bromide (1) or N-cyclohexylammonium resorcinarene chloride (2), and 1,4-diiodooctafluorobutane and accompanying small solvent guests (methanol, acetonitrile and water) are presented. The guests’ inclusion affects the geometry of the cavity of the receptors 1 and 2, while the divalent halogen bond donor 1,4-diiodooctafluorobutane determines the overall nature of the halogen bond assembly. The crystal lattice of 1 contains two structurally different dimeric assemblies A and B, formally resulting in the mixture of a capsular dimer and a dimeric pseudo-capsule. 1H and 19F NMR analyses …
ChemInform Abstract: Gold(I)-Catalyzed Intermolecular Oxyarylation of Alkynes: Unexpected Regiochemistry in the Alkylation of Arenes.
2010
The reaction between acetylenes and sulfoxides, studied as a test case for gold-catalyzed intermolecular addition, provides the oxyarylation compounds 3 in good yields. Unpredictably, in all cases a single regioisomer arising from the electrophilic aromatic alkylation at the position adjacent to the sulfur atom is obtained instead of the expected Friedel−Crafts regioisomer. A new concerted mechanism based on DFT calculations is proposed to account for the products in this intermolecular gold(I)-catalyzed reaction.