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921.
Gomes JA Gossage JL Balu H Kesmez M Bowen F Lumpkin RS Cocke DL 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(13-14):3082-3086
The theoretically predicted water-oxygen van der Waals adduct has been experimentally confirmed by vibrational characterization using matrix isolation spectroscopic studies at 10 K. Vibrational bands for asymmetric and symmetric OH-stretching for this adduct have been found at 3728 cm(-1) and 3639 cm(-1), respectively. Theoretical calculations performed with Gaussian 98 software at the MP2/6-311++G(2d,2p) level of theory support the alternative structure of the hydrated complex proposed by this study. 相似文献
922.
A series of 22 novel 1,2-disubstituted-1H-benzimidazole-N-alkylated-5- carboxamidine derivatives were synthesized and evaluated for in vitro antibacterial activity against S. aureus and methicillin resistant S. aureus (MRSA), E. coli, E. faecalis and for antifungal activity against C. albicans. Compound 59 [1-(2,4-dichlorobenzyl)-N- (2-diethylaminoethyl)-1H-benzimidazole-5-carboxamidine], with a 3,4-dichlorophenyl group at the C-2 position, displayed the greatest activity (MIC = 3.12 microg/mL against both some bacteria and the fungus C. albicans). 相似文献
923.
Turgut?K?l?? Y.?Kemal?Y?ld?z Güla?t??Top?uEmail author Ahmet?C.?G?ren Mehmet?Ay Satish?G.?Bodige William?H.?Watson 《Journal of chemical crystallography》2005,35(8):647-650
Sideroxol (1), a kaurane diterpene which has the ent-7α,18-dihydroxy-15β,16β-epoxykaurane structure (MW = 320.47, C20H32O3) was obtained from the acetone extract of Sideritis leptoclada plant as well as from some other Sideritis species. It crystallizes in the orthorhombic space group P21, 21, 21 with a = 10.967(3), b = 24.555(5), c = 6.372(4) Å, Dc = 1.240 g cm−3, Z = 4, and refines to R = 0.065 for 721 independent reflections. The skeleton consists of three fused six-membered rings and a five-membered ring with fused epoxide. The six membered rings exhibited slightly distorted chair conformation. In addition to sideroxol, two kaurane and five kaurene diterpenes were isolated from the hexane and acetone extracts of the studied plant. 相似文献
924.
AbstractThe presented work reports anticholinesterase and antioxidant activities of extracts, fractions from aerial parts, fruits, flowers, roots and isolated compounds of roots from Leiotulus dasyanthus (bergapten, pimpinellin, umbelliferone, quercetin, rutin and kaempferol). Phenolic contents, antioxidant activities of samples were carried out by Folin-Ciocalteu, DPPH, TBA methods. Anticholinesterase activity was evaluated by Ellman’s method. The highest and lowest total phenolic content were detected in root MeOH extract (88.6?mg GAE g?1 DW) and aerial part (51.83?mg GAE g?1 DW), respectively. The highest antioxidant activity among isolated secondary metabolites got coumarins umbelliferone, bergapten and pimpinellin. Pimpinellin (66.55%) and umbelliferone (61.09%) demonstrated strong inhibition towards acetylcholinesterase and butyrylcholinesterase, respectively. Dichloromethane fraction of root demonstrated significant inhibition against AChE (49.66%) and BuChE (92.21%) at 20 µg/mL. Dichloromethane fractions of roots had a notableness antioxidant and anticholinesterase activities. The further studies on roots will be important for development use of this plant for pharmaceutical and food research needs. 相似文献
925.
Ozsoz M Erdem A Ozkan D Kara P Karadeniz H Meric B Kerman K Girousi S 《Bioelectrochemistry (Amsterdam, Netherlands)》2005,67(2):199-203
Electrochemical DNA biosensors have become strong candidates for DNA based analysis. Allele-specific genotyping is also one of the important research areas, where electrochemical approaches provide promising advances. Recently reported two methods based on electrochemical guanine and colloidal gold (Au) nanoparticle oxidation signals are reviewed and compared with the existing genotyping methods in this report. 相似文献
926.
Trace quantities of selenium can be determined in the presence of iron, copper and lead using anodic stripping voltammetry, depositing at –0.60 V in 0.1M HClO4 and stripping in the anodic direction. Two separate peaks are observed at –0.25 V and –0.10 V belonging to copper and selenium, respectively. Sometimes one peak may be observed for both copper and selenium. In this case one more stripping (without deposition) must be done to obtain separate peaks. After standard addition, two strippings have to be done also. With this proposed method, 10–7
M selenium could be determined as (1.09±0.03) × 10–7
M with a 90% confidence interval in blood samples without any separation.Presented at Xth National Chemistry Congress, Bursa, Turkey, September 19–21, 1994 相似文献
927.
?smail Y?lmaz Mehmet Kandaz Ali Riza ?zkaya At?f Koca 《Monatshefte für Chemie / Chemical Monthly》2002,21(2):609-622
2,3-Dibromo-6,7,13,14,15,16,22,23-octahydro-14,15-bis-(hydroxyimino)-tribenzo [e,k,q][1,4,7,10,13,16]tetraoxadiazacyclohexadecine (LH4) was prepared by condensation of 1,2-bis-(2′-aminophenoxyethoxy)-4,5-dibromobenzene with cyanogen-di-N-oxide. Mono-, di-, and trinuclear transition metal complexes of this ligand ((LH3)2Ni, (LH3)2Zn, (LH3)2Co, (LH3)2Cu, (LH3)2Fe, (LH3)2(UO2)2(OH)2, (LH)2Cu3, (LH)2Co3) were synthesized under basic conditions. The electrochemical properties of the mono- and dinuclear complexes were studied by cyclic voltammetry in DMSO solution containing TBAP. The results showed that all redox processes are based on the metal center and the oxime ligands stabilize the Ni(III), Fe(III), Co(III), and Cu(III) species formed during oxidation. The Fe(II) and U(VI)O2 complexes displayed a different behaviour: a reduction peak with the corresponding anodic signal during the reverse scan was observed. The oxime moiety also stabilizes U(V)O2 which forms during the reduction process of the uranyl complex. Cu(II) was adsorbed on the electrode surface upon scanning cathodically. 相似文献
928.
Surfactants treatment of crude oil contaminated soils 总被引:4,自引:0,他引:4
This study reports experimental measurements investigating the ability of a biological (rhamnolipid) and a synthetic (sodium dodecyl sulfate, SDS) surfactant to remove the North Sea Ekofisk crude oil from various soils with different particle size fractions under varying washing conditions. The washing parameters and ranges tested were as follows: temperature (5 to 50 degrees C), time (5 to 20 min), shaking speed (80 to 200 strokes/min), volume (5 to 20 cm3), and surfactant concentration (0.004 to 5 mass%). The contaminated soils were prepared in the laboratory by mixing crude oil and soils using a rotating cylindrical mixer. Two contamination cases were considered: (1) weathered contamination was simulated by keeping freshly contaminated soils in a fan assisted oven at 50 degrees C for 14 days, mimicking the weathering effect in a natural hot environment, and (2) nonweathered contamination which was not subjected to the oven treatment. The surfactants were found to have considerable potential in removing crude oil from different contaminated soils and the results were comparable with those reported in literature for petroleum hydrocarbons. The removal of crude oil with either rhamnolipid or SDS was within the repeatability range of +/-6%. The most influential parameters on oil removal were surfactant concentration and washing temperature. The soil cation exchange capacity and pH also influenced the removal of crude oil from the individual soils. However, due to the binding of crude oil to soil during weathering, low crude oil removal was achieved with the weathered contaminated soil samples. 相似文献
929.
Azo compounds were prepared by the reaction between benzenediazonium chloride and 4-amino-5-hydroxy-2,7-naphthalenedisulfonic
acid monosodium salt under alkaline conditions. Two new azo-linked Schiff base ligands, 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxyphenylazo)-2,7-naphthalene
disulfonic acid disodium salt (H2L) and 4-(3-methoxysalicylidene)-5-hydroxy-6-(2-hydroxy-4-cholorophenylazo)-2,7-naphthalenedisulfonic acid disodium salt (H2L1), have been synthesized. Also, the new CuII, NiII and CoII complexes of the azo-linked Schiff base ligands were prepared and characterized by infrared spectra, UV–Vis, 1H- and 13C-n.m.r., attached proton test (APT) and distortionless enhancement by polarization transfer (DEPT) and atomic absorption
spectroscopy, mass spectrocopy, elemental analyses, thermogravimetric analysis, conductivity and magnetic measurements. It
was determined that the synthesized ligands were comprised of six-membered rings due to intramolecular hydrogen bonding. The
results suggested that condensation of the azo-derivative compounds and o-vanillin in a 1:1 molar ratio produces mononuclear Schiff base ligands with an ONO donor set. Preliminary histological studies
were made. Magnetic moment studies showed that all complexes have a tetrahedral configuration. 相似文献
930.
?. ?smail K?rba?lar Selin ?ahin Mehmet Bilgin 《The Journal of chemical thermodynamics》2006,38(12):1503-1509
(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end composition were examined for mixtures of {water (1) + propionic acid (2) + octanol or nonanol or decanol or dodecanol (3)} at T = 298.15 K and 101.3 ± 0.7 kPa. The reliability of the experimental tie-line data was confirmed by using the Othmer-Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region. 相似文献