排序方式: 共有30条查询结果,搜索用时 15 毫秒
1.
Suhrid Banskota Hassan Brim Yun Han Kwon Gulshan Singh Sidhartha R. Sinha Huaqing Wang Waliul I. Khan Hassan Ashktorab 《Molecules (Basel, Switzerland)》2021,26(11)
Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract with an incompletely understood pathogenesis. Long-standing colitis is associated with increased risk of colon cancer. Despite the availability of various anti-inflammatory and immunomodulatory drugs, many patients fail to respond to pharmacologic therapy and some experience drug-induced adverse events. Dietary supplements, particularly saffron (Crocus sativus), have recently gained an appreciable attention in alleviating some symptoms of digestive diseases. In our study, we investigated whether saffron may have a prophylactic effect in a murine colitis model. Saffron pre-treatment improved the gross and histopathological characteristics of the colonic mucosa in murine experimental colitis. Treatment with saffron showed a significant amelioration of colitis when compared to the vehicle-treated mice group. Saffron treatment significantly decreased secretion of serotonin and pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6, in the colon tissues by suppressing the nuclear translocation of NF-κB. The gut microbiome analysis revealed distinct clusters in the saffron-treated and untreated mice in dextran sulfate sodium (DSS)-induced colitis by visualization of the Bray–Curtis diversity by principal coordinates analysis (PCoA). Furthermore, we observed that, at the operational taxonomic unit (OTU) level, Cyanobacteria were depleted, while short-chain fatty acids (SCFAs), such as isobutyric acid, acetic acid, and propionic acid, were increased in saffron-treated mice. Our data suggest that pre-treatment with saffron inhibits DSS-induced pro-inflammatory cytokine secretion, modulates gut microbiota composition, prevents the depletion of SCFAs, and reduces the susceptibility to colitis. 相似文献
2.
Longitudinal vortices disrupt the growth of the thermal boundary layer, thereby the vortex generators producing the longitudinal vortices are well known for the enhancement of heat transfer in compact heat exchangers. The present investigation determines the heat transfer characteristics with secondary flow analysis in plate fin triangular ducts with delta wing vortex generators. This geometrical configuration is investigated for various angles of attack of the wing i.e. 15°, 20°, 26° and 37° and Reynolds numbers 100 and 200. The constant wall temperature boundary condition is used. The solution of the complete Navier Stokes equation and the energy equation is carried out using the staggered grid arrangement. The performance of the combination of triangular secondary fins and delta wing with stamping on slant surfaces has also been studied. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
3.
A practical approach to polyfunctionally substituted 4,7-dihydropyrazolo[3,4-b]pyridine derivatives from heteroaryl hydrazine, 3-aryl-3-oxopropanenitriles and aldehydes have been described in the report. The present catalyst-free protocol involves the intermediacy of 5-aminopyrazole and α-cyanochalcone, which undergoes in situ Michael addition to afford title compounds in moderate to good yields. All the steps were conducted concomitantly to render the procedure as practical and straightforward as possible. The expeditious synthetic protocol experiment takes less than one hour and shows broad substrate scope. 相似文献
4.
Gulshan Ara Shariff E. Kabir Kalipada Kundu K. M. Abdul Malik 《Journal of chemical crystallography》2003,33(11):851-857
The dimeric complex [Mn2(-pyS)2(CO)6] (1) reacted with 2 equivalents of 2,2-bipyridyl (bipy), 1,10-phenanthroline (phen), and ethylenediamine (en) to give the corresponding monomeric complexes [Mn(1-pyS)(bipy)(CO)3] (2), [Mn(1-pyS)(phen)(CO)3] (3), and [Mn( 1-pyS)(en)(CO)3] (4). The pyS ligand in these complexes acts as a monodentate, two-electron donor ligand, which coordinates to manganese through the sulfur atom. This is confirmed by an X-ray structure determination of 2, which contains two structural isomers in the asymmetric unit. Crystals of this compound are the monoclinic, space group P2
1/c, a = 21.593(4), b = 10.463(2), c = 16.385(3) Å, = 102.468(13)°, V = 3614.5(12) Å3, and Z = 8. The three CO groups are facially distributed in both isomers, but the relative positions of the pyS and bipy ligands are different. 相似文献
5.
Forced degradation studies on glipizide are conducted under the conditions of hydrolysis, oxidation, photolysis, and dry heat. The solutions are subjected to liquid chromatographic (LC) investigations to establish the number of products formed in each condition. The degradation products are characterized through isolation and subsequent NMR, IR, and MS spectral analyses, or through LC-mass spectrometry (MS) fragmentation pattern study. The drug is shown to degrade in 0.1M HCl at 85 degrees C to two products: 5-methyl-N-[2-(4-sulphamoylphenyl)ethyl]pyrazine-2-carboxamide (II) and methyl N-[4-[2-{(5-methyl-2-pyrazinoyl)amino}ethyl] phenyl]sulfonyl carbamate (III). The latter, a methyl ester, is formed only in the presence of methanol (used as a solubilizer), and does not appear on use of acetonitrile. III is shown to convert to II on continued heating in acid. The drug degrades slowly in water at the same temperature, and both II and III could be seen in the chromatograms until the end of the study. The heating of the drug in alkali (0.1M NaOH) at 85 degrees C yields 5-methyl-2-pyrazinecarboxylic acid (IV), along with a small quantity of 4-(2-aminoethyl) benzenesulfonamide (I). On extended heating in the same condition, a new product, 4-(2-aminoethyl)-N,N-bis[(cyclohexylamino)carbonyl] benzenesulfonamide (VI) is formed in small quantities. At the lower temperature of 40 degrees C, the drug converts under each hydrolytic condition and in both the absence and presence of light to products II, III, or IV, along with a new product, 1-cyclohexyl-3-[[4-(2aminoethyl)phenyl] sulfonyl]urea (V). The light catalyzes formation of V, and it is formed until one or two weeks, after which its level decreases. The drug remains stable in 30% H2O2, except that products II and III appear as small peaks due to acidic character of the peroxide solution. Also, the drug remains unaffected in solid state under thermal and photolytic stress conditions. Based on the results, a more complete picture on degradation pathway of the drug is obtained, highlighting a clear advantage of the approach suggested by International Conference on Harmonization. 相似文献
6.
Sulekh Chandra Krishna B. Pandeya Gulshan L. Sawhney Jagdish S. Baijal 《Transition Metal Chemistry》1980,5(1):80-82
Summary Mössbauer studies of high-spin iron(II) complexes of the type FeL2X2 [L = cyclohexanonesemicarbazone (CHSC); X = Cl, NO3, 0.5 SO4, NCS] have been carried out at room and at liquid nitrogen temperature. The results reveal doublet ground states for Fe(CHSC)2Cl2 and Fe(CHSC)2(NO3)2 and singlet ground states for Fe(CHSC)2SO4 and Fe(CHSC)2(NCS)2. 相似文献
7.
JPC – Journal of Planar Chromatography – Modern TLC - The Ziziphus fruits are recognized as a rich source of biologically active compounds, such as polysaccharides, phenolics,... 相似文献
8.
Joseph Openy Gulshan Amrahova Jen-Yao Chang Dr. Anaïs Noisier Dr. Peter ‘t Hart 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(39):e202201121
Introduction of unnatural amino acids can significantly improve the binding affinity and stability of peptides. Commercial availability of such amino acids is limited, and their synthesis is a long and tedious process. We here describe a method that allows the functionalization of peptides directly on solid-support by converting lysine residues to Katritzky salts, and subjecting them to a photochemical Giese reaction under mild reaction conditions. The method avoids the need for amino acid synthesis and instead offers a late-stage modification route for rapid peptide diversification. While numerous modification approaches at the lysine amine have been described, this work provides the first example of deaminative functionalization of peptides at lysine. The two-step protocol is compatible with various substrates, lysine analogues, resins, and all proteinogenic amino acids. Finally, by leveraging solid-phase modification, this protocol facilitates the functionalization of longer peptides as was demonstrated using biologically relevant peptides of up to 15 amino acids. 相似文献
9.
Akbar B. Aliev Gulshan Kh. Shafieva 《Mathematical Methods in the Applied Sciences》2023,46(1):1185-1205
In this paper, being investigated an initial-boundary value problem for a one-dimensional wave equation with a nonlinear source of variable order and nonlinear dissipation at the boundary. The existence of a local solution of the problem under consideration is proved. Then the question of the absence of global solutions is investigated. Depending on the relationship between the order of growth of the nonlinear source and the nonlinear boundary dissipation, different results are obtained on the blow-up of weak solutions in a finite time interval. 相似文献
10.