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排序方式: 共有153条查询结果,搜索用时 234 毫秒
1.
Zahid H. Chohan Humayun Pervez A. Rauf Khalid M. Khan Ghulam M. Maharvi 《Journal of enzyme inhibition and medicinal chemistry》2013,28(2):161-168
A new series of antibacterial and antifungal triazine-derived mono- and di-substituted (symmetrical and unsymmetrical) Schiff-bases and their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments and IR and electronic spectral measurements. IR spectra indicated the ligands to act as tridentate towards divalent metal ions via a trazine-N, the azomethine-N and, indole-NH and deprotonated-O of salicylaldehyde. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II) and Zn(II)complexes and square-pyramid for Cu(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The results of these studies show the metal complexes to be more antibacterial/antifungal against two or more species as compared to the uncomplexed Schiff-base ligands. 相似文献
2.
James A. Cahill Richard E. Green Tara L. Fulton Mathias Stiller Flora Jay Nikita Ovsyanikov Rauf Salamzade John St. John Ian Stirling Montgomery Slatkin Beth Shapiro 《PLoS genetics》2013,9(3)
Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are the Alaskan ABC Islands brown bears that show evidence of shared ancestry with polar bears. We present an analysis of genome-wide sequence data for seven polar bears, one ABC Islands brown bear, one mainland Alaskan brown bear, and a black bear (U. americanus), plus recently published datasets from other bears. Surprisingly, we find clear evidence for gene flow from polar bears into ABC Islands brown bears but no evidence of gene flow from brown bears into polar bears. Importantly, while polar bears contributed <1% of the autosomal genome of the ABC Islands brown bear, they contributed 6.5% of the X chromosome. The magnitude of sex-biased polar bear ancestry and the clear direction of gene flow suggest a model wherein the enigmatic ABC Island brown bears are the descendants of a polar bear population that was gradually converted into brown bears via male-dominated brown bear admixture. We present a model that reconciles heretofore conflicting genetic observations. We posit that the enigmatic ABC Islands brown bears derive from a population of polar bears likely stranded by the receding ice at the end of the last glacial period. Since then, male brown bear migration onto the island has gradually converted these bears into an admixed population whose phenotype and genotype are principally brown bear, except at mtDNA and X-linked loci. This process of genome erosion and conversion may be a common outcome when climate change or other forces cause a population to become isolated and then overrun by species with which it can hybridize. 相似文献
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The lonchaeid fly Silba capsicarum is recorded for the first time from the island of Java where it is considered a potential pest of chilli pepper. The taxonomy and ecology of the species is reviewed and comparisons are drawn with Lonchaeidae attacking Capsicum spp. in the Neotropics. Initial results on the level of infestation in Java are provided. 相似文献
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Chohan ZH Pervez H Khan KM Rauf A Supuran CT 《Journal of enzyme inhibition and medicinal chemistry》2004,19(1):51-56
A method is described for the preparation of novel cephalexin-derived furanyl-, thiophenyl-, pyrrolyl-, salicylyl- and pyridyl-containing compounds showing potent antibacterial activity. The binding of these newly synthesized antibacterial agents with metal ions such as cobalt(II), copper(II), nickel(II) and zinc(II) has been studied and their inhibitory properties against various bacterial species such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae are also reported. These results suggest that metal ions to possess an important role in the designing of metal-based antibacterials and that such complexes are more effective against infectious diseases compared to the uncomplexed drugs. 相似文献
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Badshah A Subhan F Rauf K Bukhari NI Shah K Khan S Ahmed Z Khan I 《AAPS PharmSciTech》2011,12(2):525-533
Controlled-release (CR) matrix tablet of 4 mg risperidone was developed using flow bound dry granulation–slugging method to improve its safety profile and compliance. Model formulations F1, F2, and F3, consisting of distinct blends of Methocel® K100 LV-CR and Ethocel® standard 7FP premium, were slugged. Each batch of granules (250–1,000 μm), obtained by crushing the slugs, was divided into three portions after lubrication and then compressed to 9-, 12-, and 15-kg hard tablets. In vitro drug release studies were carried out in 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) using a paddle dissolution apparatus run at 50 rpm. The CR test tablet, containing 30% Methocel® and 60% Ethocel® (F3) with 12-kg hardness, exhibited pH-independent zero-order release kinetics for 24 h. The drug release rate was inversely proportional to the content of Ethocel®, while the gel layer formed of Methocel® helped in maintaining the integrity of the matrix. Changes in the hardness of tablet did not affect the release kinetics. The tablets were reproducible and stable for 6 months at 40 ± 2°C/75 ± 5% relative humidity. Risperidone and its active metabolite, 9-hydroxyrisperidone, present in the pooled rabbit’s serum, were analyzed with HPLC-UV at λmax 280 nm. The CR test tablet exhibited bioequivalence to reference conventional tablet in addition to the significantly (p < 0.05) optimized peak concentration, Cmax, and extended peak time, Tmax, of the active moiety. There was a good association between drug absorption in vivo and drug release in vitro (R2 = 0.7293). The successfully developed CR test tablet may be used for better therapeutic outcomes of risperidone.KEY WORDS: controlled release, dry granulation slugging method, risperidone 相似文献
9.
The frequency of in vitro callus induction and plant regeneration is influenced by several factors, including composition of culture medium, explant source, and the genotype. Crosses between regenerable and non-regenerable upland cotton cultivars were evaluated for hybrid vigour towards regeneration responses, which is consequential in recalcitrant crop species like cotton where regeneration is limited only to a few cultivars. The results indicated that regenerable and non-regenerable parental cultivars had similar potential of producing callus, but differed in producing callus weight and embryogenic calli. Mean performance of crosses, regarding callus induction, callus weight, callus growth rate, percent embryo induction, and percentage of germinating embryos, deviated considerably from the performance of their parents, signifying the presence of hybrid vigour for the expression of these traits. Magnitude of hybrid vigour varied across hormonal levels. Genetic component was evident for all the traits although of lower magnitude. The results indicated that genetic component in the phenotypic expression of callus growth, percentages of embryo induction and germinating embryos was higher than that of callus induction, callus weight and percentage of embryogenic calli. Hormonal concentration in the media had affect on the degree of gene expression responsible for regeneration in upland cotton. Over, partial- and additive-dominance types of gene effects were apparent in the expression of these traits. Genotype × growth regulator level interaction caused considerable variation in the expression of regeneration responses, suggesting that determination of specific level of growth regulator concentration in the medium was necessary for a particular genotype to obtain optimum response. Genotype × explant source interaction was, however, relatively less important. Differences among genotypes for percent embryo induction were clearly evident. 相似文献
10.
Shafqat Nadeem Saeed Ahmad Tahira Fazeelat Muhammad Khawar Rauf Sadia Siddiq Abdul Hameed 《Inorganica chimica acta》2010,363(13):3261-3269
Palladium(II) complexes with triphenylphosphine (PPh3) and thioamides of the general formulae, [Pd(L)2(PPh3)2]Cl2 and [Pd(L)2(PPh3)2] have been prepared and characterized by elemental analysis, IR and NMR (1H, 13C and 31P) methods, and two of them (trans-[Pd(PPh3)2(Dmtu)2]Cl2·(H2O)(CH3OH)0.5 (1) and trans-[Pd(PPh3)2(Mpy)2] (2)) by X-ray crystallography; where L = thiourea (Tu), methylthiourea (Metu), N,N′-dimethylthiourea (Dmtu), tetramethylthiourea (Tmtu), 2-mercaptopyridine (Mpy), 2-mercaptopyrimidine (Mpm) and thionicotinamide (Tna). The spectral data of the complexes are consistent with the sulfur coordination of thioamides to palladium(II). The crystal structures of the complexes show that (1) has ionic character consisting of [Pd(PPh3)2(Dmtu)2]+2 cations and uncoordinated Cl− ions, while (2) is a neutral complex with Mpy behaving as anionic thiolate ligand. The coordination environment around palladium in (2) is nearly regular square-planar, while in (1) the trans angles show significant distortions from 180°. The complexes were screened for antibacterial effects, brine shrimps lethality bioassay and antitumor activity. These complexes showed significant activities in most of the cases against the tested bacteria as compared to that of a standard drug. Their antitumor activity against prostate cancer cells (PC3) is comparable with doxorubicin, together with no cytotoxic effects in brine shrimps lethality bioassay study. 相似文献