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71.
72.
Tsai YH Götze S Azzouz N Hahm HS Seeberger PH Varon Silva D 《Angewandte Chemie (International ed. in English)》2011,50(42):9961-9964
Building blocks: A new, general synthetic strategy, which allows the construction of branched glycosylphosphatidylinositols (GPIs), enables the synthesis of parasitic glycolipid 1 from Toxoplasma gondii. In addition, the structure is further confirmed by recognition of monoclonal antibodies. 相似文献
73.
Zhang P Razi N Eugenio L Fentabil M Kitova EN Klassen JS Bundle DR Ng KK Ling CC 《Chemical communications (Cambridge, England)》2011,47(45):12397-12399
The structure of the pentasaccharide S259-1 in the Consortium for Functional Glycomics was investigated using a variety of techniques. Surprisingly, the structure differs from the structure assumed from the previously established specificity of the human fucosyltransferase FUT-III used in the last step of chemoenzymatic synthesis. When presented with a tetrasaccharide substrate containing both type I and type II disaccharide moieties, the enzyme generates a pentasaccharide in which the type II moiety is preferentially fucosylated. The unexpected product generated by FUT-III in this case highlights the importance of performing detailed structural analysis on products generated by enzymes. 相似文献
74.
Novel polymer metal complexes were prepared by the condensation polymerization of a polymeric ligand with transition metal ions of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The polymeric ligand was prepared by the addition polymerization of urea with toluene 2,4‐diisocyanate in 1:1 molar ratio. The polymeric ligand and its polymer metal complexes were characterized by elemental analysis, Fourier transform infrared spectroscopy, 13C‐NMR, and1H‐NMR (nuclear magnetic resonance). The geometry was determined by electronic spectra and magnetic moment measurement. Thermogravimetric analysis (TGA) was utilized to find out the degradation process of the polyurea ligand and the polymer metal complexes. The TGA data revealed that all the metal‐containing polyureas are much more thermally stable than the corresponding polyurea ligand. The surface morphology of the polyurea ligand and cobalt(II)‐containing polyureas was determined by scanning electron micrographs. The antibacterial and antifungal activities of all the synthesized polymers were investigated against Staphylococcus aureus, Escherichia coli, and Bacillus subtilis (bacteria) and Aspergillus niger, Candida albicans, and Aspergillus flavus (fungi). These compounds show remarkably good biocidal activities, which were enhanced after complexation with the metal. Batch adsorption studies of the ligand were carried out for malachite green dye, and the polyurea ligand was found to be a good adsorbent for this dye. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
75.
The major environmental factor limiting the range of adaptation for wheat is drought. Fourteen wheat genotypes (Triticum aestivum L.) were grown under two environments (irrigated and rain fed) to determine physiological and photosynthetic responses to drought. Combined analysis of variance of the data showed that the environment was a significant source of variation for leaf chlorophyll content (LCC), stomatal conductance (g(s)) and grain yield (GY). Wheat genotypes differed significantly for LCC, g(s) and GY. All the measured traits under water-stress conditions except maximum photochemical efficiency of PSII (F(v)/F(m)) were lower than those under nonstress conditions. Mean GY in rain-fed conditions was 11.26% lower than that in irrigated conditions. The genotypes number 13 (Marvdasht) and 8 (M-81-13) exhibited the highest GY per unit area in both irrigation and rain-fed conditions. It was concluded that the higher LCC and g(s) under drought-stress conditions could possibly be the proper criteria for screening the drought-tolerant wheat genotypes under field conditions. 相似文献
76.
Ali Reza Kazemizadeh Nasrin Hajaliakbari Roghayeh Hajian Nahid Shajari Ali Ramazani 《Helvetica chimica acta》2012,95(4):594-597
The three‐component reaction of isocyanides 1 , carbodiimides 2 , and trimethylsilyl azide ( 3 ) occurs at room temperature, and the produced 1,5‐disubstituted 1H‐tetrazole derivatives 4 are formed in 81–98% yields (Scheme 1, Table). The reaction proceeds smoothly and cleanly under mild conditions, and no side reactions are observed. 相似文献
77.
Nahid Mashkouri Najafi Mohammad Eidizadeh Shahram Seidi Ensieh Ghasemi Reza Alizadeh 《Microchemical Journal》2009,93(2):159-163
Electrodeposition is known to be proper for separation and preconcentration of extremely low concentrations of analytes from the bulk sample which is instrumentally very simple. In the present research, a combination of electrodeposition with arc atomic emission spectrometry (ED-AAES) method has been developed in order to improve the analytical performance of this spectrometry technique. The results show that sensitivity and detection limits by using ED-AAES were improved 1000–2000 folds over those of normal arc atomic emission spectrometry in determination of the selected elements. The detection limits for measurement of Ni, Cr and Pb were 2.56, 3.05 and 2.11 µg L− 1 for monodeposition and 3.31, 3.72 and 3.25 µg L− 1 for simultaneously deposition, respectively. The precision of determination was in the range of 2–4% RSD. Typical calibration graphs for these elements were linear up to 100 µg L− 1, depending on the element and matrix.Application of this technique was also tested on determination of the studied elements in an electroplating plant's waste water. The accuracy of technique was verified by comparing the results of the waste water analysis with those of electrothermal atomic absorption spectroscopy as a reference standard method.The obtained results show that the combined technique (ED-AAES) has been progressed substantially toward the ultimate goal of direct interference-free determination of trace analysis in complex samples by AAES. 相似文献
78.
Ali Ebrahimi Mostafa Habibi Nahid Hesabi 《International journal of quantum chemistry》2009,109(3):629-638
Intermolecular hydrogen bonding in X3CH···NH3 (X = H, F, Cl, and Br) complexes has been studied by B3LYP, B3PW91, MP2, MP3, MP4, and CCSD methods using 6‐311++G(d,p) and AUG‐cc‐PVTZ basis sets. These complexes could exist in both eclipsed (EC) and staggered (ST) forms. The differences between binding energies of EC and ST forms are negligible and all EC and ST shapes correspond to minimum stationary states. The order of stabilities of them is in an agreement with the results of atoms in molecules (AIM) and natural bond orbital (NBO) analyses. On the basis of low differences between binding energies, ST forms are more stable than EC forms in all complexes with the exception of Br3CH···NH3, which behaves just opposite. Although the differences between binding energies are negligible, they are consistent with the results of AIM analysis. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 相似文献
79.
In this work, porous poly (2-methoxyaniline) film prepared in the presence of sodium dodecyl sulfate (P2MA-SDS) is used as a potent support for dispersion of bimetallic palladium-copper nanoparticles (Pd-Cu NPs) towards the electrooxidation of formic acid (HCOOH) in sulfuric acid solution. The Pd-Cu NPs are prepared through galvanic replacement reaction between PdII ions and Cu particles. The SEM, EDS, and electrochemical methods were used to characterize the prepared Pd-Cu NPs. The obtained results show that the Pd-Cu exhibited significantly high current density of HCOOH oxidation compared to other catalysts and utilization of Cu NPs enhances the electrocatalytic activity towards electrooxidation. The enhanced performance is related to the synergetic effect between Pd-Cu NPs and P2MA-SDS film. The effects of galvanic replacement time, potential sweep rates, and concentration of HCOOH on the catalytic activity of the electrocatalyst as well as long-term stability are investigated by the various electrochemical techniques. 相似文献
80.
Mohammadiparsa Nahid Habibi Safdar Dekan Július Janotová Irena Švec Peter Galdun Ladislav Varga Rastislav Kmječ Tomáš Bujdoš Marek Miglierini Marcel 《Journal of Radioanalytical and Nuclear Chemistry》2019,322(2):691-697
Journal of Radioanalytical and Nuclear Chemistry - The effect of minor substitution of carbon on the structure and magnetic properties of Fe–Si–B–Cu-type metallic glasses was... 相似文献