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排序方式: 共有377条查询结果,搜索用时 359 毫秒
21.
Nehal Gupta Kshitij Verma Sarath Nalla Alok Kulshreshtha Rajiv Lall Sahdeo Prasad 《Molecules (Basel, Switzerland)》2020,25(22)
Free radicals, generally composed of reactive oxygen species (ROS) and reactive nitrogen species (RNS), are generated in the body by various endogenous and exogenous systems. The overproduction of free radicals is known to cause several chronic diseases including cancer. However, increased production of free radicals by chemotherapeutic drugs is also associated with apoptosis in cancer cells, indicating the dual nature of free radicals. Among various natural compounds, curcumin manifests as an antioxidant in normal cells that helps in the prevention of carcinogenesis. It also acts as a prooxidant in cancer cells and is associated with inducing apoptosis. Curcumin quenches free radicals, induces antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), and upregulates antioxidative protein markers–Nrf2 and HO-1 that lead to the suppression of cellular oxidative stress. In cancer cells, curcumin aggressively increases ROS that results in DNA damage and subsequently cancer cell death. It also sensitizes drug-resistant cancer cells and increases the anticancer effects of chemotherapeutic drugs. Thus, curcumin shows beneficial effects in prevention, treatment and chemosensitization of cancer cells. In this review, we will discuss the dual role of free radicals as well as the chemopreventive and chemotherapeutic effects of curcumin and its analogues against cancer. 相似文献
22.
We show the existence of nonthreshold bound states of (p,q) string networks and D3-branes, preserving 1/4 of the full type-IIB supersymmetry, interpreted as string networks "dissolved" in D3-branes. We also explicitly write down the expression for the mass density of the system and discuss the extension of the construction to other Dp-branes. Differences in our construction of string networks with the ones interpreted as dyons in N = 4 gauge theories are also pointed out. 相似文献
23.
24.
Amarendra Patra Apurba K. Mukhopadhyay Alok K. Mitra Aditi K. Acharyya 《Magnetic resonance in chemistry : MRC》1981,15(1):99-101
Some carbon-13 NMR signal assignments of diazepam, flurazepam, clonazepam and chlordiazepoxide have been revised and the assignments of nitrazepam are reported. The assignments of the various resonances were made by considering the changes in chemical shifts produced by the change of substituents and also by comparison with the chemical shifts of model compounds. 相似文献
25.
A. Dey A. C. Kulshreshtha G. M. Saha 《Annals of the Institute of Statistical Mathematics》1972,24(1):525-528
Summary Two methods of construction of partially balanced arrays of strength two and three are presented. 相似文献
26.
Gharah N Chakraborty S Mukherjee AK Bhattacharyya R 《Chemical communications (Cambridge, England)》2004,(22):2630-2632
A combination of the newly synthesized and structurally characterized compound, [MoO(O2)2(saloxH)](saloxH2= salicylaldoxime) as catalyst, H2O2 as terminal oxidant and NaHCO3 as co-catalyst when stirred in CH3CN (10 cm3) at room temperature (rt) shows a very pronounced efficiency epoxidation of olefinic compounds, the method being green and economical. 相似文献
27.
R.K. Shukla Atul Kumar Alok Shukla Kirti Srivastava 《Journal of Molecular Liquids》2008,140(1-3):117-122
Density, ultrasonic velocity, surface tension, excess volume and viscosity of quaternary non-electrolyte solution n-pentane+tolune+n-heptane+cyclohexane has been experimentally determined at 25 °C over a wide range of composition. Assuming a quaternary fluid solution to be made of six binaries, a statistical approach of Prigogine–Flory–Patterson (PFP) theory has been extended to develop the expressions for dynamic viscosity, surface tension excess volume and ultrasonic velocity of quaternary fluid system. A reasonable agreement has been achieved between theory and experiment. An attempt has also bee made to explain the nature of molecular interactions involved in the light of excess thermodynamic functions whose sign and magnitude depend upon the chain length and size of the component fluids and also studied the role of order breakers (toluene and cyclohexane) on these properties. 相似文献
28.
A series of some new mixed ligand complexes have been synthesized with an objective for evaluation as antimicrobials. Reactions of diorganotin(IV) dichloride with dibenzoyl methane and O‐alkyl trithiophosphates in a 1:1:1 molar ratio in refluxing benzene yield products of the type [PhCOCHCOPh]R2Sn‐[SSH(S)POR'] [where R = Me, Bu, Ph; R' = Me, Et, Pri, Bui, Ph]. The newly synthesized complexes are light yellow colored crystalline solids, non‐volatile, soluble in common organic solvents, monomeric in nature and highly sensitive towards atmospheric moisture. These complexes are characterized by elemental analysis, IR and multinuclear NMR (1H, 31P and 119Sn) spectral studies. Spectral studies of these complexes indicate that dibenzoyl methane and O‐alkyl trithiophosphate moieties are bidentate and the central tin atom is hexacoordinated in nature. A few of these compounds were tested for their antibacterial activity using standard drugs. 相似文献
29.
Gunjan Verma V. K. Aswal S. K. Kulshreshtha C. Manohar P. A. Hassan Eric W. Kaler 《Pramana》2008,71(5):997-1002
Structural parameters of micelles formed by Triton X-100 in the presence of solubilized anthranilic acid at different pH values
was investigated using light scattering and small angle neutron scattering. Analysis of the SANS data indicate that micelles
are oblate ellipsoidal in nature with little variation in the dimensions, in the investigated pH range (from 0.5 to 6.0).
The interaction potential of the micelles shows a minimum closer to the isoelectric point of anthranilic acid. A similar variation
is observed in the cloud point of the micelles with pH. The observed variation in the interaction potential with pH of the
micellar solution can be explained in terms of the reversal of charge on anthranilic acid due to shift in the acid-base equilibrium.
The variation in interaction potential and cloud point with pH is modelled using Coulombic repulsion of charged molecules
at the micelle interface.
相似文献
30.
Jeevan Jaisingh Jack Barron Shailendra Mehta Alok Chaturvedi 《European Journal of Operational Research》2008
The issues we address here are – How should a firm (e.g. Internet service provider (ISP)) that is capable of collecting personal information (browsing information, purchase history, etc.) about consumers, price its service, given that consumers vary in their valuation for privacy, and also vary in terms of the value of their personal information to a third party (firms that need consumer information)? Should the firm have a blanket policy of never collecting, or a policy of always collecting and revealing information? Surprisingly we find that in some cases the collector of information may be no worse off in the asymmetric information case than in the full information case. The paper provides a justification for the strategy of some firms such as ISP’s which never collect information and also for the strategy of other firms, like grocery stores that do. We also find that it is non-optimal for the firm to design contracts where the consumer can choose an intermediate level of privacy. 相似文献