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排序方式: 共有927条查询结果,搜索用时 31 毫秒
911.
Refat MS El-Deen IM Ibrahim HK El-Ghool S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(5):1208-1220
Cu(II), Mn(II), Ni(II), and Zn(II) metal complexes with novel heterocyclic Schiff base derived from 5-phenyl azo-salicyladehyde and o-amino benzoic acid have been synthesized and characterized on the basis of elemental analyses, electronic, IR, and (1)H NMR spectra, and also by aid of scanning electron microscopy (SEM), X-ray powder diffraction, molar ratio measurements, molar conductivity measurements, and thermogravimetric analyses. It has been found that the Schiff base behaves as neutral tridentate (ONO) ligand forming chelates with 1:1 (metal:ligand) stoichiometry. 相似文献
912.
Abstract
The palladium-rich cadmium compounds La6Pd13Cd4 and Ce6Pd13Cd4 were synthesized by induction melting the elements in sealed tantalum ampoules and subsequent annealing. They were characterized by X-ray powder and single-crystal diffraction: Na16Ba6N type, Im[`3] mIm\overline{3} m, a = 988.12(9) pm, wR2 = 0.0463, 225 F 2 values, and 12 variables for La6Pd13Cd4, and a = 982.1(2) pm, wR2 = 0.0521, 215 F 2 values, and 12 variables for Ce6Pd13Cd4. The striking structural motifs are palladium-centred La6 and Ce6 octahedra, which are packed in a bcc fashion. Further palladium and cadmium atoms built up three-dimensional [Pd3Cd] networks in which the La6Pd and Ce6Pd octahedra are embedded. Chemical bonding analyses show that the dominant interaction occurs within the palladium-centred RE 6 octahedra, while weaker bonding exists between them. 相似文献913.
Inhibition of Fungi and Gram-Negative Bacteria by Bacteriocin BacTN635 Produced by Lactobacillus plantarum sp. TN635 总被引:1,自引:0,他引:1
Slim Smaoui Lobna Elleuch Wacim Bejar Ines Karray-Rebai Imen Ayadi Bassem Jaouadi Florence Mathieu Hichem Chouayekh Samir Bejar Lotfi Mellouli 《Applied biochemistry and biotechnology》2010,162(4):1132-1146
The aim of this study was to evaluate 54 lactic acid bacteria (LAB) strains isolated from meat, fermented vegetables and dairy products for their capacity to produce antimicrobial activities against several bacteria and fungi. The strain designed TN635 has been selected for advanced studies. The supernatant culture of this strain inhibits the growth of all tested pathogenic including the four Gram-negative bacteria (Salmonella enterica ATCC43972, Pseudomonas aeruginosa ATCC 49189, Hafnia sp. and Serratia sp.) and the pathogenic fungus Candida tropicalis R2 CIP203. Based on the nucleotide sequence of the 16S rRNA gene of the strain TN635 (1,540 pb accession no FN252881) and the phylogenetic analysis, we propose the assignment of our new isolate bacterium as Lactobacillus plantarum sp. TN635 strain. Its antimicrobial compound was determined as a proteinaceous substance, stable to heat and to treatment with surfactants and organic solvents. Highest antimicrobial activity was found between pH 3 and 11 with an optimum at pH?=?7. The BacTN635 was purified to homogeneity by a four-step protocol involving ammonium sulfate precipitation, centrifugal microconcentrators with a 10-kDa membrane cutoff, gel filtration Sephadex G-25, and C18 reverse-phase HPLC. SDS-PAGE analysis of the purified BacTN635, revealed a single band with an estimated molecular mass of approximately 4 kDa. The maximum bacteriocin production (5,000 AU/ml) was recorded after a 16-h incubation in Man, Rogosa, and Sharpe (MRS) medium at 30?°C. The mode of action of the partial purified BacTN635 was identified as bactericidal against Listeria ivanovii BUG 496 and as fungistatic against C. tropicalis R2 CIP203. 相似文献
914.
915.
Thomas Harmening Adel Al Alam Samir F. Matar Hellmut Eckert Rainer Pöttgen 《Solid State Sciences》2009,11(7):1239-1245
The silicide Sc2RuSi2 was synthesized from the elements by arc-melting. The structure was refined on the basis of single crystal X-ray diffractometer data: Zr2CoSi2 type, C2/m, a = 1004.7 (2), b = 406.8 (1), c = 946.6 (2) pm, β = 117.95 (2), wR2 = 0.0230, 743 F2 values, and 32 variables. The structure consists of a rigid three-dimensional [RuSi2] network in which the two crystallographically independent scandium atoms fill larger cages of coordination numbers 16 and 15, respectively. The [RuSi2] network shows short Ru–Si distances (234–247 pm) and two different Si2 pairs: Si1–Si1 at 247 and Si2–Si2 at 243 pm. Each silicon atom has trigonal prismatic Sc6 (for Si2) or Sc4Ru2 (for Si1) coordination. These building units are condensed via common edges and faces. The various Sc–Sc distances between the prisms range from 327 to 361 pm. From electronic structure investigation within DFT, chemical bonding shows a major role of Ru–Si bonding and the presence of strong electron localization around Si–Si pairs pointing to a polyanionic silicide network [RuSi2]δ?. The 45Sc MAS-NMR spectra recorded at 11.7 and 9.4 T clearly resolve the two distinct scandium sites. The large electric field gradients present at both scandium sites result in typical line shapes arising from second-order quadrupole perturbation effects. 相似文献
916.
A class of non-linear singular integral equations with Hilbert kernel and a related class of quasi-linear singular integro-differential
equations are investigated by applying Schauder's fixed point theorem in Banach spaces.
相似文献
917.
918.
919.
Samir F. Matar 《ChemInform》2008,39(36):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
920.
The European Physical Journal H - The Inter-University Centre for Astronomy and Astrophysics (IUCAA) is the second Inter-University Centre established by the Government of India for promotion of... 相似文献