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排序方式: 共有367条查询结果,搜索用时 15 毫秒
361.
Meera Moydeen Abdul Hameed Syed Ali Padusha Mohamed Khan Badr M. Thamer Nirmala Rajkumar Hany El-Hamshary Mohamed El-Newehy 《先进技术聚合物》2023,34(1):6-23
Electrospinning procedures such as blend electrospinning, coaxial electrospinning, and emulsion electrospinning have been used for the fabrication of electrospun nanofibers (ENFs) for biomedical applications. These ENFs are attracted great interest especially in drug delivery applications due to their small size, high surface area-to-volume, and porosity. The aim of this review is to focus on the controlled release mechanism among the different electrospinning methods, and the selectivity of hydrophilic, water-soluble polymers as a carrier for drug. The mechanism for the drug delivery depends mainly on the method of drug loading, polymeric interactions, and the nature of polymer swelling, erosion, or degradation. This review compressed on the literature survey about the fabrication of nanofibers by different electrospinning methods, factors affecting the nanofiber morphologies, selectivity of polymeric blends for successful controlled release behavior, and the mechanism involved in the drug release steps. 相似文献
362.
Mansoor Saburov 《Mathematical Methods in the Applied Sciences》2021,44(1):813-819
The main aim of this paper is to discuss some feature so‐called historic behavior of a discrete‐time Kolmogorov system of predator–prey interactions, which causes the nonexistence of the time averages. 相似文献
363.
Hydrodynamic focusing—a versatile tool 总被引:1,自引:0,他引:1
The control of hydrodynamic focusing in a microchannel has inspired new approaches for microfluidic mixing, separations, sensors,
cell analysis, and microfabrication. Achieving a flat interface between the focusing and focused fluids is dependent on Reynolds
number and device geometry, and many hydrodynamic focusing systems can benefit from this understanding. For applications where
a specific cross-sectional shape is desired for the focused flow, advection generated by grooved structures in the channel
walls can be used to define the shape of the focused flow. Relative flow rates of the focused flow and focusing streams can
be manipulated to control the cross-sectional area of the focused flows. This paper discusses the principles for defining
the shape of the interface between the focused and focusing fluids and provides examples from our lab that use hydrodynamic
focusing for impedance-based sensors, flow cytometry, and microfabrication to illustrate the breadth of opportunities for
introducing new capabilities into microfluidic systems. We evaluate each example for the advantages and limitations integral
to utilization of hydrodynamic focusing for that particular application. 相似文献
364.
ABSTRACT: BACKGROUND: Benzimidazole derivatives are structurally bioisosteres of naturally occurring nucleotides, which makes them compatible with biopolymers of living systems. This property gives benzimidazole a biological and clinical importance. In the last decade, this class of compounds has been reported to possess anti-allergic, anti-diabatic, anti-HIV, anti-hypertensive, anti-inflammatory, anti-mycobacterial, anti-oxidant, anti-protozoal, and anti-viral properties. The researchers are now interested to explore their potential as anti-cancer agents. In the present study, an effort was made to further explore this area of research. Furthermore, in order to increase the solubility and efficacy of these heterocycles, the interest is now shifted to the salts of these compounds. With this background, we planned to synthesize a series of meta-xylyl linked bis-benzimidazolium salts to assess their anti-proliferation efficacy on human colon cancer cell line (HCT 116). RESULTS: A number of N-alkylbenzimidazoles were synthesized by reactions of benzimidazole with alkyl halides (i-PrBr, PrBr, EthBr, Pent-2-ylBr, BuBr, BenzCl, HeptBr). The subsequent treatment of the resulting N-alkylbenzimidazoles with 1,3-(bromomethylene)benzene afforded corresponding bis-benzimidazolium salts. All synthesized compounds were characterized by spectroscopic techniques (Additional file 1: NMR & FT-IR) and microanalysis. Molecular structures of selected compounds were established through single crystal x-ray diffraction studies. All the compounds were assessed for their anti-proliferation test on human colorectal cancer cell line (HCT 116). Results showed that the compounds exhibited dose dependent cytotoxicity towards the colon cancer cells with IC50 ranges between 0.1 to 17.6 muM. The anti-proliferation activity of all compounds was more pronounced than that of standard reference drug 5-flourouracil (IC50 =19.2 muM). CONCLUSIONS: All the synthesized bis-benzimidazolium salts showed potential anticancer activity. Out of them, some of these salts showed IC50 value as low as 0.1-0.2 muM. Based on the results it can be concluded that, the bis-benzimidazolium salts could probably be the potential source of chemotherapeutic drugs. 相似文献
365.
Influence of film thickness on non-equilibrium energy transport in the aluminum thin film is examined. The solutions of Boltzmann equation and the modified two-equation model are presented to predict electron and phonon temperatures in the film for various film thicknesses. It is found that electron and phonon temperatures predicted from the Boltzmann equation differ from the solution of two-equation model in the film for small film thickness. As the film thickness increases, this difference becomes negligibly small. Two-equation model predicts higher electron and phonon temperatures than those obtained from the solutions of the Boltzmann equation in the vicinity of the high temperature edge. This becomes opposite in the region of the low temperature edge. 相似文献
366.
Roshan Ahmad Mohammad Zia-ul-Haq Shahid Hameed Humaira Akhtar Helmut Duddeck 《Monatshefte für Chemie / Chemical Monthly》2000,131(4):393-400
Summary. A convenient procedure is reported for the preparation of benzofuro-annelated 2-phenyl-1,5-benzothiazepine derivatives by
oxidative cyclocondensation of phenolic β-diketones with o-aminothiophenol in DMSO. The regiochemistry of these compounds is proven by HMBC signals and the existence of a five-bond 19F,13C-2 coupling. Surprisingly, treatment with LiAlH4 at room temperature led to a double reduction under opening of the five-membered ring. Refluxing such solutions with a higher
amount of LiAlH4 gave rise to a further reduced derivative possessing the trans-configuration. All structures (regio- and stereochemistry) were assigned on the basis of NMR spectroscopic data.
Received November 22, 1999. Accepted December 21, 1999 相似文献
367.
Kulsoom Zahara Yamin Bibi Saadia Masood Sobia Nisa Abdul Qayyum Muhammad Ishaque Khurram Shahzad Waseem Ahmed Zahid Hussain Shah Hameed Alsamadany Seung-Hwan Yang Gyuhwa Chung 《Molecules (Basel, Switzerland)》2021,26(19)
Gui Zhen Cao is an herbal formulation that has been documented in Chinese traditional medicine as a remedy for diarrhea, dysentery, inflammation, and toxicity. The sources of this formulation (Bidens pilosa L., Bidens biternata (Lour.) Merr. & Sherff, Bidens bipinnata L.) are also listed in ethnomedicinal reports all over the world. In this study, all these plants are tested for in vitro anticandida activity. A quantitative evaluation of the phytochemicals in all these plants indicated that their vegetative parts are rich in tannins, saponins, oxalates, cyanogenic glycoside and lipids; moreover, the roots have high percentages of alkaloids, flavonoids, and phenols. The results indicated significant anticandida activity, especially for the hexane extract of B. bipinnata leaves which inhibited C. albicans (42.54%), C. glabrata (46.98%), C. tropicalis (50.89%), C. krusei (40.56%), and C. orthopsilosis (50.24%). The extract was subjected to silica gel chromatography and 220 fractions were obtained. Purification by High Performance Liquid Chromatography with Diode-Array Detection (HPLC–DAD) and Gas Chromatography tandem Mass Spectrometry (GC-MS/MS) analysis led to the identification of two anticandida compounds: dehydroabietic and linoleic acid having an inhibition of 85 and 92%, respectively. 相似文献