排序方式: 共有12条查询结果,搜索用时 78 毫秒
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Drug delivery systems (DDS) are used to achieve a higher therapeutic effects of a pharmaceutical drug or natural compound in a specific diseased site with minimal toxicological effect and these systems consists of liposomes, microspheres, gels, prodrugs and many. Nanotechnology is a rapidly developing multi-disciplinary science that ensures the fabrication of the polymers to nanometer scale for various medical applications. Uses of biopolymers in DDS ensure the biocompatibility, biodegradability and low immunogenicity over the synthetic ones. Biopolymers such as silk fibroins, collagen, gelatin, albumin, starch, cellulose and chitosan can be easily made into suspension that serve as delivery vehicles for both macro and mini drug molecules. There are various methods such as supercritical fluid extraction, desolvation, electrospraying, spray-drying, layer-by-layer self-assembly, freeze-drying and microemulsion introduced to make these DDS. This drug carrier systems enhance the drug delivery actively and can be used in ocular, transdermal, dental or intranasal delivery systems. This review describes the new trends in nanomaterials based drug delivery systems mainly using biopolymers such as proteins (silk fibroin, collagen, gelatin and albumin) and polysaccharides (chitosan, alginate, cellulose and starch). 相似文献
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We present a first calculation of the generalized parton distributions of the photon (both polarized and unpolarized) using overlaps of light-front wave functions at leading order in α and zeroth order in αs; for non-zero transverse momentum transfer and zero skewness. We present the novel parton content of the photon in transverse position space. 相似文献
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Kuhn A Sreeraj P Pöttgen R Wiemhöfer HD Wilkening M Heitjans P 《Journal of the American Chemical Society》2011,133(29):11018-11021
The intermetallic compounds Li(x)Si(y) have attracted considerable interest because of their potential use as anode materials in Li ion batteries. In addition, the crystalline phases in the Li-Si phase diagram turn out to be outstanding model systems for the measurement of fast Li ion diffusion in solids with complex structures. In the present work, the Li self-diffusivity in crystalline Li(12)Si(7) was thoroughly probed by (7)Li NMR spin-lattice relaxation (SLR) measurements. Variable-temperature and -frequency NMR measurements performed in both the laboratory and rotating frames of reference revealed three distinct diffusion processes in Li(12)Si(7). The diffusion process characterized by the highest Li diffusivity seems to be confined to one dimension. It is one of the fastest motions of Li ions in a solid at low temperatures reported to date. The Li jump rates of this hopping process followed Arrhenius behavior; the jump rate was ~10(5) s(-1) at 150 K and reached 10(9) s(-1) at 425 K, indicating an activation energy as low as 0.18 eV. 相似文献
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Sreeraj Gopi Augustine Amalraj Shintu Jude K.T. Benson Preetha Balakrishnan Józef T. Haponiuk 《高分子科学杂志,A辑:纯化学与应用化学》2019,56(4):327-340
Turmeric spent, a by-product of turmeric processing industries, was used as a source to prepare nanofibers (NF). The chemical treatments methods followed by acid hydrolysis accompanied with high pressure homogenization were used to prepare NF. The resulting turmeric nanofibers (TNF) were characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA/DTA). The TNF presented needle like structure, high thermal stability, an average width of 38.5?nm, average length of 245.7?nm, and giving an aspect ratio (L/D) of 23.15. The prepared TNF showed pronounced antimicrobial activity against Bacillus cereus, Escherichia Coli, Salmonella typhimurium and Staphylococcus aureus and also registered good antioxidant activity. The results showed that TNF were successfully obtained from turmeric spent and might be potentially applied in different fields, such as pharmaceutical, biological active species, nutraceuticals, components for food industries and bionanocomposites. 相似文献
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Puravankara Sreeraj Rolf-Dieter Hoffmann Armin Kirfel 《Journal of solid state chemistry》2006,179(2):355-361
Large quantities of single phase, polycrystalline LiIrSn4 have been synthesised from the elements by melting in sealed tantalum tubes and subsequent annealing. LiIrSn4 crystallises with an ordered version of the PdGa5 structure: I4/mcm, a=655.62(8), . The lithium atoms were clearly localised from a neutron powder diffraction study: RP=0.147 and RF=0.058. Time-dependent electrochemical polarisation techniques, i.e. coulometric titration, chronopotentiometry, chronoamperometry and cyclic voltammetry were used to study the kinetics of lithium ion diffusion in this stannide. The range of homogeneity (Li1+ΔδIrSn4, −0.091?δ?+0.012) without any structural change in the host structure and the chemical diffusion coefficient (∼10−7-10−9 cm2/s) point out that LiIrSn4 is a first example of a large class of intermetallic compounds with lithium and electron mobility. Optimised materials from these ternary lithium alloys may be potential electrode material for rechargeable lithium batteries. 相似文献
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Gopalakrishnapanicker Rajesh Krishnan Modiyuzhathil K. Sreeraj Krishnapillai Sreekumar 《Comptes Rendus Chimie》2013,16(8):736-741
Poly(vinyl chloride) was modified to develop an alternative support for the preparation of polymer-supported catalysts. Commercially available poly(vinyl chloride) was synthetically modified to a polymer containing pendant primary amino groups. The Schiff-base of salicylaldehyde and the amino polymer were prepared and were used as the ligands in the synthesis of a polymer-supported copper complex. The polymer-supported ligand and catalysts were characterized by various physical methods. The polymer with the pendant copper complex was able to catalyze the one-pot three-component Mannich reaction between aldehydes, ketones and anilines under mild and environmentally friendly conditions. The catalyst can be recovered by simple filtration and is reusable. 相似文献
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We present a calculation of the generalized parton distributions of the photon using overlaps of photon light-front wave functions. 相似文献
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Puravankara Sreeraj 《Journal of solid state chemistry》2005,178(11):3420-3425
The ternary stannides LixRh3Sn7−x (x=0.45, 0.64, 0.80) and LixIr3Sn7−x (x=0.62 and 0.66) were synthesized from the elements in sealed tantalum tubes in a water-cooled sample chamber of an induction furnace. The samples were characterized by X-ray diffraction on powders and single crystals. The stannides adopt the cubic Ir3Ge7-type structure (space group , Z=4). In this structure type the tin atoms occupy the Wyckoff positions 12d and 16f and form two interpenetrating frameworks consisting of cubes and square antiprisms. The rhodium and iridium atoms center the square antiprisms and are arranged in pairs. With increasing lithium substitution the lattice parameter of Ir3Sn7 (936.7) decreases via 932.2 pm (x=0.62) to 931.2 pm (x=0.66), while the Ir-Ir distance remains almost the same (290 pm). A similar trend is observed for the rhodium compounds. The lithium atoms substitute Sn on both framework sites. However, the 16f site shows a substantially larger preference for Li occupation. This is in contrast to the isotypic magnesium based compounds. 相似文献