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排序方式: 共有1131条查询结果,搜索用时 343 毫秒
71.
Lalit Giri Arun Kumar Jugran Amit Bahukhandi Praveen Dhyani Indra D. Bhatt Ranbeer Singh Rawal Shyamal Kumar Nandi Uppeandra Dhar 《Applied biochemistry and biotechnology》2017,181(1):267-282
Habenaria edgeworthii Hook. f. ex Collett is an important terrestrial orchid used in different Ayurvedic formulations. In the present study, variations among morphological, phytochemical and molecular markers were assessed. A significant difference was observed among populations using morphological traits. Inter-simple sequence repeat (ISSR) data revealed lower genetic diversity at population level (He = 0.207) as compared to species level (He = 0.334). Analysis of molecular variance (AMOVA) indicates 74 % variation among populations and 26 % within population. Tuber extracts showed significantly (p < 0.05) higher total phenolics and flavonoids among the populations. Antioxidant activity determined by 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays exhibited considerable antioxidant potential. Furthermore, the associations between molecular and morphological and phytochemical attributes were studied using multiple regression analysis (MRA). Several ISSR fragments were associated with some morphological and phytochemical traits. These ISSR fragments can be useful for breeding programme of the species when no other genetic information, such as linkage maps and quantitative trait loci, is available. 相似文献
72.
Chen Z Concepcion JJ Luo H Hull JF Paul A Meyer TJ 《Journal of the American Chemical Society》2010,132(50):17670-17673
The complex [Ru(Mebimpy)(bpy)(OH(2))](2+) [Mebimpy = 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; bpy = 2,2'-bipyridine] and its 4,4'-(PO(3)H(2)CH(2))(2)bpy derivative on oxide electrodes are water oxidation catalysts in propylene carbonate and 2,2,2-trifluoroethanol (TFE) to which water has been added as a limiting reagent. The rate of water oxidation is greatly enhanced relative to that with water as the solvent and occurs by a pathway that is first-order in H(2)O; an additional pathway that is first-order in acetate appears when TFE is used as the solvent. 相似文献
73.
Amit Katiyar Stephen W. Thiel Vadim V. GuliantsNeville G. Pinto 《Journal of chromatography. A》2010,1217(10):1583-1588
The adsorption of bovine serum albumin (BSA) and lysozyme (LYS) on siliceous SBA-15 with 24 nm pores was studied using flow microcalorimetry; this is the first attempt to understand the thermodynamics of protein adsorption on SBA-15 using flow microcalorimetry. The adsorption mechanism is a strong function of protein structure. Exothermic events were observed when protein–surface interactions were attractive. Entropy-driven endothermic events were also observed in some cases, resulting from lateral protein–protein interactions and conformational changes in the adsorbed protein. The magnitudes of the enthalpies of adsorption for primary protein–surface interactions decrease with increased surface coverage, indicating the possibility of increased repulsion between adsorbed protein molecules. Secondary exothermic events were observed for BSA adsorption, presumably due to secondary adsorption made possible by conformational changes in the soft BSA protein. These secondary adsorption events were not observed for lysozyme, which is structurally robust. The results of this study emphasize the influence of solution conditions and protein structure on conformational changes of the adsorbed protein and the value of calorimetry in understanding protein–surface interactions. 相似文献
74.
Patwa AN Gonnade RG Kumar VA Bhadbhade MM Ganesh KN 《The Journal of organic chemistry》2010,75(24):8705-8708
X-ray crystallographic studies of methylene linked Ferrocene-bis(thymine/uracil) conjugates Fc(T:T)(M) and Fc(U:U)(M) reveal base dependent 2-D supramolecular assemblies generated via wobble self-pairing for bis-thymine and reverse wobble self-pairing for bis-uracil conjugates, differing in architecture from the corresponding butylene spacer linked conjugates. 相似文献
75.
Joanna Luszczyn Marta E. Plonska‐Brzezinska Dr. Amit Palkar Dr. Alina T. Dubis Dr. Agneta Simionescu Dr. Dan T. Simionescu Dr. Beata Kalska‐Szostko Dr. Krzysztof Winkler Prof. Dr. Luis Echegoyen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(16):4870-4880
Small carbon nano‐onions (CNOs, 6–8 shells) were prepared in high yield and functionalized with carboxylic groups by chemical oxidation. After functionalization these nanostructures were soluble in aqueous solutions. 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2 tetrazolium (MTS) tests showed excellent cytocompatibility of all CNOs analyzed at 30 and 300 μg mL?1, so these carbon nanostructures can be safely used for biological applications. The first covalent functionalization of oxidized CNOs (ox‐CNOs) with biomolecules, by using biotin–avidin interactions is reported here. Multilayers were prepared on a gold surface by layer‐by‐layer assembly and the process was monitored by surface plasmon resonance (SPR) spectroscopy and atomic force microscopy (AFM). Covalent binding of molecules to the short amine‐terminated organosulfur monolayers was assessed by Fourier transform infrared spectroscopy using total attenuated reflactance mode (FT‐IR/HATR). 相似文献
76.
To the best of our knowledge till now there is no method in the literature to find the exact fuzzy optimal solution of unbalanced
fully fuzzy transportation problems. In this paper, the shortcomings and limitations of some of the existing methods for solving
the problems are pointed out and to overcome these shortcomings and limitations, two new methods are proposed to find the
exact fuzzy optimal solution of unbalanced fuzzy transportation problems by representing all the parameters as LR flat fuzzy numbers. To show the advantages of the proposed methods over existing methods, a fully fuzzy transportation problem
which may not be solved by using any of the existing methods, is solved by using the proposed methods and by comparing the
results, obtained by using the existing methods and proposed methods. It is shown that it is better to use proposed methods
as compared to existing methods. 相似文献
77.
Mukherjee and Basu proposed a new method for solving fuzzy assignment problems. In this paper, some fuzzy assignment problems
and fuzzy travelling salesman problems are chosen which cannot be solved by using the fore-mentioned method. Two new methods
are proposed for solving such type of fuzzy assignment problems and fuzzy travelling salesman problems. The fuzzy assignment
problems and fuzzy travelling salesman problems which can be solved by using the existing method, can also be solved by using
the proposed methods. But, there exist certain fuzzy assignment problems and fuzzy travelling salesman problems which can
be solved only by using the proposed methods. To illustrate the proposed methods, a fuzzy assignment problem and a fuzzy travelling
salesman problem is solved. The proposed methods are easy to understand and apply to find optimal solution of fuzzy assignment
problems and fuzzy travelling salesman problems occurring in real life situations. 相似文献
78.
Amit P. Gabale 《Journal of sound and vibration》2011,330(11):2596-2607
A methodology for determining reduced order models of periodically excited nonlinear systems with constant as well as periodic coefficients is presented. The approach is based on the construction of an invariant manifold such that the projected dynamics is governed by a fewer number of ordinary differential equations. Due to the existence of external and parametric periodic excitations, however, the geometry of the manifold varies with time. As a result, the manifold is constructed in terms of temporal and dominant state variables. The governing partial differential equation (PDE) for the manifold is nonlinear and contains time-varying coefficients. An approximate technique to find solution of this PDE using a multivariable Taylor-Fourier series is suggested. It is shown that, in certain cases, it is possible to obtain various reducibility conditions in a closed form. The case of time-periodic systems is handled through the use of Lyapunov-Floquet (L-F) transformation. Application of the L-F transformation produces a dynamically equivalent system in which the linear part of the system is time-invariant; however, the nonlinear terms get multiplied by a truncated Fourier series containing multiple parametric excitation frequencies. This warrants some structural changes in the proposed manifold, but the solution procedure remains the same. Two examples; namely, a 2-dof mass-spring-damper system and an inverted pendulum with periodic loads, are used to illustrate applications of the technique for systems with constant and periodic coefficients, respectively. Results show that the dynamics of these 2-dof systems can be accurately approximated by equivalent 1-dof systems using the proposed methodology. 相似文献
79.
In this paper, we have developed a simple mathematical model which is used for the calculation of blocking probability of network. A generic routing and wavelength assignment algorithm has also been proposed for the optimization and minimization of blocking probability. The implementation of the proposed model has less complexity and the computation used in this model is quite efficient. This paper suggests an optimum path and assigns wavelength to that path, as a solution to routing and wavelength assignment problem to have least blocking probability. This model can be implemented on different network topologies. Further, the model is also used to evaluate the blocking performance of a 6-node simple network topology and hence used to improve its performance on the basis of blocking probability. 相似文献
80.
In this paper, the various Optical Burst Switching (OBS) reservation schemes have been examined in order to reduce data loss caused by either channel scheduling or resources. A novel multi-service OBS edge node with synchronized bandwidth reservation mechanism (SRM) has been proposed, which enables high-speed network transport nodes to dynamically reserve bandwidth needed for active data burst flows. The performance of the proposed mechanism is evaluated by means of NS-2 simulation. The results show that the packet delay is kept within the constraint for each traffic flow and the performance metrics such as burst loss rate, throughput and fairness are remarkably improved. 相似文献