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431.
Reactions of [Fe2(CO)6(μ-pdt)] (1) (pdt = SCH2CH2CH2S) and small bite-angle diphosphines have been studied. A range of products can be formed being dependent upon the nature of the diphosphine and reaction conditions. With bis(diphenylphosphino)methane (dppm), thermolysis in toluene leads to the formation of a mixture of bridge and chelate isomers [Fe2(CO)4(μ-dppm)(μ-pdt)] (2) and [Fe2(CO)4(κ2-dppm)(μ-pdt)] (3), respectively. Both have been crystallographically characterised, 3 being a rare example of a chelating dppm ligand in a first row binuclear system. At room temperature in MeCN with added Me3NO · 2H2O, the monodentate complex [Fe2(CO)5(κ1-dppm)(μ-pdt)] (4) is initially formed. Warming 4 to 100 °C leads the slow conversion to 2, while oxidation (on alumina) gives [Fe2(CO)5(κ1-dppmO)(μ-pdt)] (5). With bis(dicyclohexylphosphino)methane (dcpm), heating in toluene cleanly affords [Fe2(CO)4(μ-dcpm)(μ-pdt)] (6). With Me3NO · 2H2O in MeCN the reaction is not clean as the phosphine is oxidised but monodentate [Fe2(CO)5(κ1-dcpm)(μ-pdt)] (7) can be seen spectroscopically. With 1,2-bis(diphenylphosphino)benzene (dppb) and cis-1,2-bis(diphenylphosphino)ethene (dppv) the chelate complexes [Fe2(CO)4(κ2-dppb)(μ-pdt)] (8) and [Fe2(CO)4(κ2-dppv)(μ-pdt)] (9), respectively are the final products under all conditions, although a small amount of [Fe2(CO)5(κ2-dppvO)(μ-pdt)] (10) was also isolated. Protonation of 2 with HBF4 affords a cation with poor stability while with the more basic diiron centre in 6 readily forms the stable bridging-hydride complex [(μ-H)Fe2(CO)4(μ-dcpm)(μ-pdt)][BF4] (11) which has been crystallographically characterised. 相似文献
432.
Khan AN Fatima I Khaliq UA Malik A Miana GA Qureshi ZU Rasheed H 《Molecules (Basel, Switzerland)》2011,16(3):2053-2064
New naturally occurring nitrogenous compounds 1 and 2, along with a new dimeric lignan glucoside 3, have been isolated from the ethyl acetate soluble fraction of Centaurea iberica. Their structures have been elucidated through spectroscopic techniques. All the isolated compounds showed significant platelet aggregation inhibition. 相似文献
433.
Fatima Tuz Johra Mi-Jung Lee Woo-Gwang Jung 《Journal of Sol-Gel Science and Technology》2013,66(3):481-487
Graphene-based composites represent a new class of materials with potential for many applications. Graphene can be attached to a metal, a semiconductor, or any polymer. In this work, our approach was to attach graphene to a well-known semiconductor, ZnO. We synthesized graphene–ZnO composites by a simple, low-cost, environmentally friendly solvothermal method, carrying out the reaction in different conditions in order to discover the optimum condition, and also to obtain a high-quality product. Our research demonstrated that the optimum temperature to obtain a high-quality product is 180 °C for 20 h. All obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy, electron dispersion spectrometry, X-ray photoelectron spectrometry, Raman spectroscopy, Fourier transform infrared spectrometry, UV–visible spectrophotometry, and thermogravimetric analysis. The XRD confirmed that the crystal structure of the ZnO in the nanocomposite was wurtzite type. The prepared composite was stable to 800 °C with its 80 % weight. 相似文献
434.
Fatima Tahiri Yunsen Li David Hawke Luciane Ganiko Igor Almeida Steven Levery 《Journal of carbohydrate chemistry》2013,32(1):44-67
α-1,3-Terminated galactose residues on glycoproteins and glycosphingolipids are recognized by natural anti-α-1,3-galactose antibodies in human serum and cause hyperacute rejection in pig-to-human xenotransplantation. Genetic depletion of α-1,3-galactosyl- transferase-1 in pigs abolishes the hyperacute rejection reaction. However, the isoglo- botriosylceramide (iGb3) synthase in pigs may produce additional α-1,3-terminated galactose residues on glycosphingolipids. In both α-1,3-galactosyltranserase-1 knockout mice and pigs, cytotoxic anti-α-1,3-galactose antibodies could be induced; thus, a paradox exists that anti-α-1,3-galactose antibodies are present in animals with functional iGb3 synthases. Furthermore, iGb3 has been found to be an endogenous antigen for natural killer T (NKT) cells, an innate type of lymphocyte that may initiate the adaptive immune responses. It has been reasoned that iGb3 may trigger the activation of NKT cells and cause the rejection of α-1,3-galactosyltransferase-1-deficient organs through the potent stimulatory effects of NKT cells on adaptive immune cells (see ref.[20]). In this study, we examined the expression of iGb3 and the isoglobo-series glycosphingolipids in pig organs, including the heart, liver, pancreas, and kidney, by ion-trap mass spectrometry, which has a sensitivity of measuring 1% iGb3 among Gb3 isomers, when 5 μg/mL of the total iGb3/Gb3 mixture is present (see ref.[35]). We did not detect iGb3 or other isoglobo-series glycosphingolipids in any of these organs, although they were readily detected in mouse and human thymus and dendritic cells. The lack of iGb3 and isoglobo-series glycosphingolipids in pig organs indicates that iGb3 is unlikely to be a relevant immune epitope in xenotransplantation. 相似文献
435.
Pilar Rodríguez-Rodríguez Silvia M. Arribas Angel Luis López de Pablo M. Carmen González Fatima Abderrahim Luis Condezo-Hoyos 《Analytical and bioanalytical chemistry》2013,405(21):6863-6871
The assessment of collagen content in tissues is important in biomedical research, since this protein is altered in numerous diseases. Hydroxyproline and Sirius red based assays are the most common methods for collagen quantification. However, these procedures have some pitfalls, such as the requirement of oxygen-free medium or expensive equipment and large sample size or being unsuitable for hydrolyzed collagen, respectively. Our objective was to develop a specific, versatile, and user-friendly quantitative method applicable to small tissue samples and extracts obtained from elastin purification, therefore, suitable for simultaneous quantification of elastin. This method is based on the binding of Sirius red to collagen present in a sample immobilized on a PVDF membrane, as in the dot-blot technique, and quantified by a scanner and image analysis software. Sample loading, Sirius red concentration, temperature and incubation time, type of standard substance, albumin interference, and quantification time are optimized. The method enabled the quantification of (1) intact collagen in several rat tissue homogenates, including small resistance-sized arteries, (2) partially hydrolyzed collagen obtained from NaOH extracts, compatible with elastin purification, and (3) for the detection of differences in collagen content between hypertensive and normotensive rats. We conclude that the developed technique can be widely used since it is versatile (quantifies intact and hydrolyzed collagen), requires small sample volumes, is user-friendly (low-cost, easy to use, minimum toxic materials, and reduced time of test), and is specific (minimal interference with serum albumin). Figure
Dot-blot–Sirius red-based assay for collagen quantification 相似文献
436.
Irfan Ullah Musa Kaleem Baloch Gulrez Fatima Durrani 《Journal of solution chemistry》2011,40(7):1341-1348
The solubilities of two nonsteroidal anti-inflammatory (MELOXICAM and CELECOXIB) drugs, were determined in aqueous solutions
of nonionic (Tween 20, Tween 80, Brij 30, Brij 35, Triton X 100, Triton X 114) surfactants. These surfactants have different
numbers of oxyethylene units and their micelles showed different aggregation numbers. It is shown that these surfactants have
different abilities to solubilize NSAIDs drugs. The solubilities of the drugs increased linearly with the increase in concentration
of surfactants. The sizes of micelles remained constant with the addition of the drugs, except for Triton type surfactants
in which case the size of the micelles decreased. It was observed that the number of oxyethylene units in the surfactants,
aggregation number of the micelles and HLB play key roles in solubilizing the drugs. 相似文献
437.
A novel multi-switching dual compound synchronization scheme is proposed for chaotic systems which has not been investigated so far. The goal is to design appropriate controllers by using Lyapunov stability theory and nonlinear control to establish the asymptotically stable synchronized state for six drive and two response systems. Multi-switching dual compound synchronization can be considered as an extension of multi-switching dual combination synchronization. An example is presented to elaborate the proposed scheme where Lorenz, Chen, Lu systems are considered as master systems and T system is considered as slave system. The results obtained by theoretical and graphical analysis are in excellent agreement. 相似文献
438.
Zeolites are often used as supports for metals and metal oxides because of their well-defined microporous structure and high surface area. In this study, nano-zeolite Y (50–150 nm range) and micro-zeolite Y (500–800 nm range) were loaded with WO3, by impregnating the zeolite support with ammonium metatungstate and thermally decomposing the salt thereafter. Two different loadings of WO3 were studied, 3 wt.% and 5 wt.% with respect to the overall catalyst. The prepared catalysts were characterized for their morphology, structure, and surface areas through scanning electron microscope (SEM), XRD, and BET. They were further compared for their electrocatalytic activity for hydrogen evolution reaction (HER) in 0.5 M H2SO4. On comparing the bare micro-zeolite particles with the nano-form, the nano-zeolite Y showed higher currents with comparable overpotentials and lower Tafel slope of 62.36 mV/dec. WO3 loading brought about a change in the electrocatalytic properties of the catalyst. The overpotentials and Tafel slopes were observed to decrease with zeolite-3 wt.% WO3. The smallest overpotential of 60 mV and Tafel slope of 31.9 mV/dec was registered for nano-zeolite with 3 wt.% WO3, while the micro-zeolite gave an overpotential of 370 mV and a Tafel slope of 98.1 mV/dec. It was concluded that even with the same metal oxide loading, nano-zeolite showed superior performance, which is attributed to its size and hence easier escape of hydrogen bubbles from the catalyst. 相似文献
439.
Mudassir Farooq Faisal Usman Sumera Zaib Hamid Saeed Shah Qazi Adnan Jamil Fatima Akbar Sheikh Ajmal Khan Sameh Rabea Soheir A. A. Hagras Gaber El-Saber Batiha Imtiaz Khan 《Molecules (Basel, Switzerland)》2022,27(10)
Voriconazole (VRC) is a broad-spectrum antifungal agent belonging to BCS class II (biopharmaceutical classification system). Despite many efforts to enhance its solubility, this primary issue still remains challenging for formulation scientists. Transethosomes (TELs) are one of the potential innovative nano-carriers for improving the solubility and permeation of poorly soluble and permeable drugs. We herein report voriconazole-loaded transethosomes (VRCT) fabricated by the cold method and followed by their incorporation into carbopol 940 as a gel. The prepared VRCT were evaluated for % yield, % entrapment efficiency (EE), surface morphology, possible chemical interaction, particle size, zeta potential, and polydispersity index (PDI). The optimized formulation had a particle size of 228.2 nm, a zeta potential of −26.5 mV, and a PDI of 0.45 with enhanced % EE. Rheology, spreadability, extrudability, in vitro release, skin permeation, molecular docking, antifungal, and antileishmanial activity were also assessed for VRCT and VRC loaded transethosomal gel (VTEG). Ex-vivo permeation using rat skin depicted a transdermal flux of 22.8 µg/cm2/h with enhanced efficiency up to 4-fold. A two-fold reduction in inhibitory as well as fungicidal concentration was observed against various fungal strains by VRCT and VTEG besides similar results against L-donovani. The development of transethosomal formulation can serve as an efficient drug delivery system through a topical route with enhanced efficacy and better patient compliance. 相似文献
440.
Iman Fatima Akhtar Rasul Shahid Shah Malik Saadullah Nayyer Islam Ahmed Khames Ahmad Salawi Muhammad Masood Ahmed Yosif Almoshari Ghulam Abbas Mohammed A. S. Abourehab Sajid Mehmood Khan Zunera Chauhdary Meshal Alshamrani Nader Ibrahim Namazi Demiana M. Naguib 《Molecules (Basel, Switzerland)》2022,27(9)
The occurrence of fungal infections has increased over the past two decades. It is observed that superficial fungal infections are treated by conventional dosage forms, which are incapable of treating deep infections due to the barrier activity possessed by the stratum corneum of the skin. This is why the need for a topical preparation with advanced penetration techniques has arisen. This research aimed to encapsulate fluconazole (FLZ) in a novasome in order to improve the topical delivery. The novasomes were prepared using the ethanol injection technique and characterized for percent entrapment efficiency (EE), particle size (PS), zeta potential (ZP), drug release, Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and antifungal activity. The FN7 formulation with 94.45% EE, 110 nm PS and −24 ZP proved to be the best formulation. The FN7 formulation showed a 96% release of FLZ in 8 h. FTIR showed the compatibility of FLZ with excipients and DSC studies confirmed the thermal stability of FLZ in the developed formulation. The FN7 formulation showed superior inhibition of the growth of Candida albicans compared to the FLZ suspension using a resazurin reduction assay, suggesting high efficacy in inhibiting fungal growth. 相似文献