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881.
Abstract

Tolbutamide is an oral anti-diabetic agent for the treatment of type 2 diabetic patients. Its lower absorption results in its inferior therapeutic efficacy. Nano-carrier systems have the subject of greater interests for enhancing efficacy of such drugs. Current study was designed to improve the tolbutamide therapeutic efficacy through its delivery in Gum Xanthan (GX) stabilized green gold nanoparticles (AuNPs). GX stabilized AuNPs were characterized for surface plasmon resonance (SPR), morphology, size, polydisoersity index (PDI) and zeta potential through UV spectrophotometer, atomic force microscope (AFM) and zetasizer respectively. They were used for loading tolbutamide and loaded nanoparticles were investigated for morphology, size, PDI, zeta potential and drug loading efficiency. FT-IR analysis was used for conforming GX functional groups involvement in AuNPs stabilization and drug-excepients interactions. Tolbutamide loaded in the synthesized nanoparticles was investigated for its insulin secretion potentials in isolated mice islets. Synthesized AuNPs were found in nano-size range with spherical morphology, increased surface negativity and loaded increased concentration of drug without changing its chemical nature. They markedly enhanced the tolbutamide insulin secretion potentials as compared to simple drug solution. Results confirm that the developed nano-carrier system is highly efficient in achieving higher therapeutic efficacy of drugs like tolbutamide.  相似文献   
882.
Precise measurement of low enrichment of stable isotope labeled amino‐acid tracers in tissue samples is a prerequisite in measuring tissue protein synthesis rates. The challenge of this analysis is augmented when small sample size is a critical factor. Muscle samples from human participants following an 8 h intravenous infusion of L‐[ring‐13C6]phenylalanine and a bolus dose of L‐[ring‐13C6]phenylalanine in a mouse were utilized. Liquid chromatography tandem mass spectrometry (LC/MS/MS), gas chromatography (GC) MS/MS and GC/MS were compared to the GC‐combustion‐isotope ratio MS (GC/C/IRMS), to measure mixed muscle protein enrichment of [ring‐13C6]phenylalanine enrichment. The sample isotope enrichment ranged from 0.0091 to 0.1312 molar percent excess. As compared with GC/C/IRMS, LC/MS/MS, GC/MS/MS and GC/MS showed coefficients of determination of R2 = 0.9962 and R2 = 0.9942, and 0.9217 respectively. However, the precision of measurements (coefficients of variation) for intra‐assay are 13.0%, 1.7%, 6.3% and 13.5% and for inter‐assay are 9.2%, 3.2%, 10.2% and 25% for GC/C/IRMS, LC/MS/MS, GC/MS/MS and GC/MS, respectively. The muscle sample sizes required to obtain these results were 8 µg, 0.8 µg, 3 µg and 3 µg for GC/C/IRMS, LC/MS/MS, GC/MS/MS and GC/MS, respectively. We conclude that LC/MS/MS is optimally suited for precise measurements of L‐[ring‐13C6]phenylalanine tracer enrichment in low abundance and in small quantity samples. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
883.
The aim of this work is to develop a cheap and green chemical process and this paper describes the catalytic commotion of locally collected sand in Friedel–Craft's Acylation of aromatic compounds like benzene, anisole, aniline, naphthalene and phenol etc. The sand consists of silica and alumina as analyzed by means of EDAX and acts as a green Lewis acid. The catalyst was also characterized by using BET, SEM, and XRD techniques.  相似文献   
884.
Nanocrystalline cellulose (NCC)-reinforced poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) composite mats have been prepared by electrospinning method. Polymer electrolytes formed by activating the composite mats with 1 M lithium bis(trifluoromethanesulfonyl)imide/1-butyl-3-methypyrrolidinium bis(trifluoromethanesulfonyl)imide electrolyte solution. The addition of 2 wt% NCC in PVdF-HFP improved the electrolyte retention and storage modulus of the separator by 63 and 15 %, respectively. The developed electrolyte demonstrated high value of ionic conductivity viz. 4?×?10?4?S?cm?1 at 30 °C. Linear scan voltammetry revealed a wide electrochemical stability of the composite mat separator up to 5 V (vs. Li+/Li). Cyclic voltammetry of the polymer electrolyte with a graphite electrode in 2.5 to 0 V (vs. Li+/Li) potential range showed a reversible intercalation/de-intercalation of Li+ ions in the graphite. No peaks were observed related to the reduction of the electrolyte on the anode.  相似文献   
885.
The crystal structures of diphenyl (cycloheptylamido)phosphate, C19H24NO3P or (C6H5O)2P(O)(NHC7H13), ( I ), and diphenyl (dibenzylamido)phosphate, C26H24NO3P or (C6H5O)2P(O)[N(CH2C6H5)2], ( II ), are reported. The NHC7H13 group in ( I ) provides two significant hydrogen‐donor sites in N—H…O and C—H…O hydrogen bonds, needed for a one‐dimensional hydrogen‐bond pattern along [100] in the crystal, while ( II ), with a (C6H5CH2)2N moiety, lacks these hydrogen bonds, but its three‐dimensional supramolecular structure is mediated by C—H…π interactions. The conformational behaviour of the phenyl rings in ( I ), ( II ) and analogous structures from the Cambridge Structural Database (CSD) were studied in terms of flexibility, volume of the other group attached to phosphorus and packing forces. From this study, synclinal (±sc), anticlinal (±ac) and antiperiplanar (±ap) conformations were found to occur. In the structure of ( II ), there is an intramolecular Cortho—H…O interaction that imposes a +sc conformation for the phenyl ring involved. For the structures from the CSD, the +sc and ±ap conformations appear to be mainly imposed by similar Cortho—H…O intramolecular interactions. The large contribution of the C…H/H…C contacts (32.3%) in the two‐dimensional fingerprint plots of ( II ) is a result of the C—H…π interactions. The differential scanning calorimetry (DSC) analyses exhibit peak temperatures (Tm) at 109 and 81 °C for ( I ) and ( II ), respectively, which agree with the strengths of the intermolecular contacts and the melting points.  相似文献   
886.
Lactobacillus bulgaricus is a LAB strain which is capable of producing bacteriocin substances to inhibit Staphylococcus aureus. The aim of this study was to purify a bacteriocin-like inhibitory substance (BLIS) produced by L. bulgaricus FTDC 1211 using an aqueous impregnated resins system consisting of polyethylene-glycol (PEG) impregnated on Amberlite XAD4. Important parameters influencing on purification of BLIS, such as the molecular weight and concentration of PEG, the concentration and pH of sodium citrate and the concentration of sodium chloride, were optimized using a response surface methodology. Under optimum conditions of 11% (w/w) of PEG 4000 impregnated Amberlite XAD4 resins and 2% (w/w) of sodium citrate at pH 6, the maximum purification factor (3.26) and recovery yield (82.69% ± 0.06) were obtained. These results demonstrate that AIRS could be used as an alternate purification system in the primary recovery step.  相似文献   
887.
The limited potassium‐ion intercalation capacity of graphite hampers development of potassium‐ion batteries (PIB). Edge‐nitrogen doping is an effective approach to enhance K‐ion storage in carbonaceous materials. One shortcoming is the lack of precise control over producing the edge‐nitrogen configuration. Here, a molecular‐scale copolymer pyrolysis strategy is used to precisely control edge‐nitrogen doping in carbonaceous materials. This process results in defect‐rich, edge‐nitrogen doped carbons (ENDC) with a high nitrogen‐doping level (up to 10.5 at %) and a high edge‐nitrogen ratio (87.6 %). The optimized ENDC exhibits a high reversible capacity of 423 mAh g?1, a high initial Coulombic efficiency of 65 %, superior rate capability, and long cycle life (93.8 % retention after three months). This strategy can be extended to design other edge‐heteroatom‐rich carbons through pyrolysis of copolymers for efficient storage of various mobile ions.  相似文献   
888.
The current investigation presents the synthesis, computational molecular-docking and biological activity studies of arylated thiazole coumarins. Aryl substituted thiazolyl coumarin derivatives were synthesized via Suzuki cross-coupling reaction. A detailed reaction condition optimization revealed that the Pd-PEPPSI-IPent precatalyst in only 2 mol% loading resulted in the desired product with high yield. The aim of this study was to examine the antimicrobial behavior of thiazole coumarin derivatives through in vitro and in silico studies. All the compounds showed activity against both antibacterial strains, Staphylococcus aureus and Escherichia coli, except 5d . Similarly, the compounds 5a , 5b , and 5d were found to be active against Trichoderma harzianum. The compound 5d of this series was found to have a higher activity with MIC 125 mg/ml against Trichoderma harzianum. Molecular studies showed the high activities of these compounds are due to the presence of strong H-bonding and π-π interaction with their respective targets. A good correlation was observed between computational and in vitro studies.  相似文献   
889.
Russian Journal of Applied Chemistry - Surface chemistry of carbon black (CB) plays a major role towards its dispersion in liquid media. In this study a simple approach of surface modification has...  相似文献   
890.
We modeled and studied three types of novel B12C24N12 cages. The structure of these cages was inspired by those of BC2N nanotubes and the B24N24 fulborene skeleton. Density functional theory was used to investigate the various properties of the cages. All three isomers of B12C24N12 were vibrationally stable. The highest occupied molecular orbital‐lowest unoccupied molecular orbital band gap was dependent on the BC2N cage type. The B12C24N12‐II cage was the most favorable nanocage and exhibited a large electric dipole moment. Natural bonding orbital (NBO) analysis confirmed the existence of lone pairs and unoccupied orbitals in the B12C24N12 cages. New donor–acceptor interactions of natural MOs (Molecular Orbitals) were observed in BC2N nanocages. The NBO and atomic polar tensor charges appeared to be fairly well correlated, showing that atomic charges can be obtained at a lower computational cost in this way.  相似文献   
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