排序方式: 共有40条查询结果,搜索用时 15 毫秒
1.
Aye Ünlü Kerem Teral Zübeyde Uurlu Aydn Ali A. Dnmez Hasan Soliman Yusufolu hsan al 《Molecules (Basel, Switzerland)》2022,27(3)
Polygala species are frequently used worldwide in the treatment of various diseases, such as inflammatory and autoimmune disorders as well as metabolic and neurodegenerative diseases, due to the large number of secondary metabolites they contain. The present study was performed on Polygala inexpectata, which is a narrow endemic species for the flora of Turkey, and resulted in the isolation of nine known compounds, 6,3′-disinapoyl-sucrose (1), 6-O-sinapoyl,3′-O-trimethoxy-cinnamoyl-sucrose (tenuifoliside C) (2), 3′-O-(O-methyl-feruloyl)-sucrose (3), 3′-O-(sinapoyl)-sucrose (4), 3′-O-trimethoxy-cinnamoyl-sucrose (glomeratose) (5), 3′-O-feruloyl-sucrose (sibiricose A5) (6), sinapyl alcohol 4-O-glucoside (syringin or eleutheroside B) (7), liriodendrin (8), and 7,4′-di-O-methylquercetin-3-O-β-rutinoside (ombuin 3-O-rutinoside or ombuoside) (9). The structures of the compounds were determined by the spectroscopic methods including 1D-NMR (1H NMR, 13C NMR, DEPT-135), 2D-NMR (COSY, NOESY, HSQC, HMBC), and HRMS. The isolated compounds were shown in an in silico setting to be accommodated well within the inhibitor-binding pockets of myeloperoxidase and inducible nitric oxide synthase and anchored mainly through hydrogen-bonding interactions and π-effects. It is therefore plausible to suggest that the previously established anti-inflammatory properties of some Polygala-derived phytochemicals may be due, in part, to the modulation of pro-inflammatory enzyme activities. 相似文献
2.
Rapid liquid chromatography-ultraviolet determination of organic acids and phenolic compounds in red wine and must 总被引:1,自引:0,他引:1
A reversed-phase liquid chromatography-ultraviolet (LC-UV) method is proposed for the rapid simultaneous analysis of the main carboxylic acids and polyphenols in must and wine. Good resolution was obtained for citric, tartaric, malic, lactic, acetic, caffeic, ellagic and gallic acids, (-)-epicatechin, quercetin and resveratrol. A novel silica-based column containing ether-linked phenyl groups, with polar end-capping and suitable for low-pH aqueous mobile phases was used and found to be superior to others tested. The method employed a mixture of 0.2% TFA in water and acetonitrile as eluents, showed linearity and precision, and was applied to samples of must and wine. 相似文献
3.
Heavy metal contamination in street dusts of Istanbul (Pendik to Levent) E-5 highway 总被引:1,自引:0,他引:1
Street dust composition is an important environmental parameter that should be considered in investigations of environmental pollution originating from traffic. In this study, fifty-six samples of street dusts were collected during the period December 2003-April 2004 from Pendik to Levent on E-5 highway in Istanbul, Turkey. Analyses were determined by graphite furnace atomic absorption spectrometry after digestion using USEPA, 1996 (Method 3050B). The mean concentration levels of Pb, Mn, Zn, Ni, Cd and Cu were found to be 368.3, 747.8, 431.2, 27.1, 0.3 and 191.1 microg/g respectively. Pb, Cu, Zn and Mn mean concentrations in studied areas were higher than levels of these heavy metals according to USEPA (1992) and Republic of Turkey Ministry of Environment and Foresty (2003). Highly significant correlations except for Mn were found between the number of vehicles and heavy metal concentrations. 相似文献
4.
Michael J. Patrick Chia-Yuan Chen David H. Frakes Onur Dur Kerem Pekkan 《Experiments in fluids》2011,50(4):887-904
In hemodynamics, the inherent intermittency of two-phase cellular-level flow has received little attention. Unsteadiness is
reported and quantified for the first time in the literature using a combination of fluorescent dye labeling, time-resolved
scanning confocal microscopy, and micro-particle image velocimetry (μPIV). The near-wall red blood cell (RBC) motion of physiologic
high-hematocrit blood in a rectangular microchannel was investigated under pressure-driven flow. Intermittent flow was associated
with (1) the stretching of RBCs as they passed through RBC clusters with twisting motions; (2) external flow through local
obstacles; and (3) transitionary rouleaux formations. Velocity profiles are presented for these cases. Unsteady flow clustered
in local regions. Extra-cellular fluid flow generated by individual RBCs was examined using submicron fluorescent microspheres.
The capabilities of confocal μPIV post-processing were verified using synthetic raw PIV data for validation. Cellular interactions
and oscillating velocity profiles are presented, and 3D data are made available for computational model validation. 相似文献
5.
This paper describes potential applications of multi-attribute preference models (MAPM) in e-commerce and offers some guidelines for their implementation. MAPM are methodologies for modeling complex preferences that depend on more than one attribute or criterion, and include multi-attribute utility theory, conjoint analysis, and the Analytic Hierarchy Process. There are numerous examples of applications in e-commerce that would benefit from the acquisition of information regarding the preferences of a consumer, a customer, an advice seeker, or a decision maker. Here, the focus is on applications of MAPM models in B2C and B2B websites, where preferences of consumers are assessed for the purpose of identifying products or services that closely match their needs. 相似文献
6.
In this paper, we study the linear stability of the interface between an Upper Convective Maxwell fluid and a hydrodynamically passive fluid subject to an electric field applied either parallel or normal to the flat interface between the two fluids. The fluids are leaky-dielectric and we apply surface-coupled model. We solve the model equations analytically and study the dispersion and neutral curves for various parameters representing the applied potential, the fluid’s elasticity, the physical and the electrical properties of the fluids, and the heights of the fluids in the presence of both normal and parallel electric fields. It is found that the critical wavenumber is independent of the Weissenberg number. However, increasing the Weissenberg number increases the maximum growth rate for both the normal and the parallel fields. The critical wavenumber increases with the dimensionless applied voltage for the normal field. Lastly for the normal field, for some values of the dimensionless parameters, the growth rate reached very large values representing some type of singularity as has been observed in the literature. However, for the same values of the parameters no singularity is observed for the parallel field. 相似文献
7.
İ. Kuban Altınel Engin Durmaz Necati Aras Kerem Can Özkısacık 《European Journal of Operational Research》2009
The capacitated multi-facility Weber problem is concerned with locating m facilities in the Euclidean plane, and allocating their capacities to n customers at minimum total cost. The deterministic version of the problem, which assumes that customer locations and demands are known with certainty, is a non-convex optimization problem and difficult to solve. In this work, we focus on a probabilistic extension and consider the situation where the customer locations are randomly distributed according to a bivariate distribution. We first present a mathematical programming formulation, which is even more difficult than its deterministic version. We then propose an alternate location–allocation local search heuristic generalizing the ideas used originally for the deterministic problem. In its original form, the applicability of the heuristic depends on the calculation of the expected distances between the facilities and customers, which can be done for only very few distance and probability density function combinations. We therefore propose approximation methods which make the method applicable for any distance function and bivariate location distribution. 相似文献
8.
Bingol K Zhang F Bruschweiler-Li L Brüschweiler R 《Journal of the American Chemical Society》2012,134(21):9006-9011
The complex metabolic makeup of a biological system, such as a cell, is a key determinant of its biological state providing unique insights into its function. Here we characterize the metabolome of a cell by a novel homonuclear (13)C 2D NMR approach applied to a nonfractionated uniformly (13)C-enriched lysate of E. coli cells and determine de novo their carbon backbone topologies that constitute the "topolome". A protocol was developed, which first identifies traces in a constant-time (13)C-(13)C TOCSY NMR spectrum that are unique for individual mixture components and then assembles for each trace the corresponding carbon-bond topology network by consensus clustering. This led to the determination of 112 topologies of unique metabolites from a single sample. The topolome is dominated by carbon topologies of carbohydrates (34.8%) and amino acids (45.5%) that can constitute building blocks of more complex structures. 相似文献
9.
10.
Kilian Roßmann Kerem C. Akkaya Pascal Poc Corentin Charbonnier Jenny Eichhorst Hannes Gonschior Abha Valavalkar Nicolas Wendler Thorben Cordes Benjamin Dietzek-Ivani Ben Jones Martin Lehmann Johannes Broichhagen 《Chemical science》2022,13(29):8605
Rhodamine fluorophores are setting benchmarks in fluorescence microscopy. Herein, we report the deuterium (d12) congeners of tetramethyl(silicon)rhodamine, obtained by isotopic labelling of the four methyl groups, show improved photophysical parameters (i.e. brightness, lifetimes) and reduced chemical bleaching. We explore this finding for SNAP- and Halo-tag labelling in live cells, and highlight enhanced properties in several applications, such as fluorescence activated cell sorting, fluorescence lifetime microscopy, stimulated emission depletion nanoscopy and single-molecule Förster-resonance energy transfer. We finally extend this idea to other dye families and envision deuteration as a generalizable concept to improve existing and to develop new chemical biology probes.Deuteration enhances photophysical and chemical properties of fluorescent rhodamine dyes for higher brightness in sensitive microscopy. 相似文献