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71.
Subhash Vaghani S. Vasanti Kiran Chaturvedi C. S. Satish S. J. Shankar 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(12):1015-1027
The aim of the present study was to prepare and evaluate microspheres of Eudragit (RS, RL and RSPO) containing an anticancer drug 5-FU. Microspheres were prepared by O/O solvent evaporation method using a acetone/liquid paraffin system. Magnesium stearate was used as the droplet stabilizer and n-hexane was added to harden the microspheres. The prepared microspheres were characterized for their micromeretic properties and entrapment efficiency; as well by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffractometry (XRPD), thin layer chromatography (TLC) and scanning electron microscopy (SEM) revealed the crystalline nature of drug in a final state. The in vitro release studies were performed in a Phosphate Buffer Solution (PBS) pH 7.4. The best fit release kinetics was achieved with a Higuchi plot. The yields of preparation and entrapment efficiencies were very high with a larger particle size for all the formulations. Mean particle size, entrapment efficiency and production yield were highly influenced by the type of polymer and polymer concentration. It is concluded from the present investigation that various Eudragit are promising controlled release carriers for 5-FU. 相似文献
72.
Alok Chaturvedi Chandra S. Sharma Padam N. Nagar 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1923-1929
Reactions of triorganotin chlorides with potassium salt of O-alkyl trithiophosphate [ROP(S)(SK)2; R = Me, Pri, Ph] in 2:1 molar ratio in anhydrous benzene yield triorganotin O-alkyl trithiophosphate of the type ROP(S) [SSnR′3]2 R = Me, Pri; Ph, R′ = Prn, Bun, Ph] which are found to be monomeric in nature. These complexes are soluble in common organic solvents. Similar reactions of diorganotin chloride with dipotassium salt of S-alkyl trithiophosphate yield diorganotin-S-alkyl trithiophosphate of the type [(RS)P(O)S2]2SnR′2; R = Me, Pri; R′ = Me, Et, Ph, which also are found to be monomeric in nature and are soluble in common organic solvents. The newly synthesized derivatives have been characterized by physicochemical and spectroscopic techniques, IR, NMR (1H, 31P, and 119Sn). 相似文献
73.
Juwar Doley Lakshya Veer Singh G. Ravi Kumar Aditya Prasad Sahoo Lovleen Saxena Uttara Chaturvedi Shikha Saxena Rajiv Kumar Prafull Kumar Singh R. S. Rajmani Lakshman Santra S. K. Palia S. Tiwari D. R. Harish Arvind Kumar G. S. Desai Smita Gupta Shishir K. Gupta A. K. Tiwari 《Applied biochemistry and biotechnology》2014,172(1):497-508
The canine parvovirus type 2 (CPV-2) causes an acute disease in dogs. It has been found to induce cell cycle arrest and DNA damage leading to cellular lysis. In this paper, we evaluated the apoptotic potential of the “new CPV-2a” in MDCK cells and elucidated the mechanism of the induction of apoptosis. The exposure of MDCK cells to the virus was found to trigger apoptotic response. Apoptosis was confirmed by phosphatidylserine translocation, DNA fragmentation assays, and cell cycle analysis. Activation of caspases-3, -8, -9, and -12 and decrease in mitochondrial potential in CPV-2a-infected MDCK cells suggested that the CPV-2a-induced apoptosis is caspase dependent involving extrinsic, intrinsic, and endoplasmic reticulum pathways. Increase in p53 and Bax/Bcl2 ratio was also observed in CPV-2a-infected cells. 相似文献
74.
S. Chaturvedi 《Zeitschrift für Physik B Condensed Matter》1983,51(3):271-277
A method developed earliier in the context of Brownian motion for elimination of fast variables is applied to certain proto-type models for nonequilibrium systems. This method is compared with that of Mori et al. 相似文献
75.
76.
Bae S Mah H Chaturvedi S Jeknic TM Baird WM Katz AK Carrell HL Glusker JP Okazaki T Laali KK Zajc B Lakshman MK 《The Journal of organic chemistry》2007,72(20):7625-7633
1,4-Difluorobenzo[c]phenanthrene (1,4-DFBcPh) and its putative metabolites, the dihydrodiol and diol epoxides, have been synthesized and structurally characterized, and the extent of DNA binding by the metabolites has been assessed. 1,4-DFBcPh and 1,4-difluoro-10-methoxybenzo[c]phenanthrene were prepared by photochemical cyclization of appropriate naphthylphenylethylenes. The dihydrodiol was synthesized from 1,4-difluoro-10-methoxybenzo[c]phenanthrene, and the diol epoxides were diastereoselectively synthesized from the dihydrodiol. Interesting differences were noted in 1H NMR spectra of the series 1 (syn) diol epoxides of benzo[c]phenanthrene (BcPh) and 1,4-DFBcPh; the BcPh diol epoxide displays a quasi-diequatorial orientation of the hydroxyl groups, but in the 1,4-DFBcPh case these are diaxially disposed. This difference probably stems from the presence of the fjord-region fluorine atom in 1,4-DFBcPh. A through-space, fjord-region H-F coupling has also been observed for 1,4-DFBcPh and its derivatives. Comparative X-ray crystallographic analyses of BcPh and 1,4-DFBcPh and their dihydrodiols show that introduction of fluorine increases the molecular distortion by about 6-7 degrees . As a guide to estimating the molecular distortion and its effects, and for comparison with the X-ray structures in known cases, optimized structures of BcPh, 1,4-DFBcPh, and 1,4-DMBcPh (the dimethyl analogue) as well as their dihydrodiols and diol epoxides were computed. Relative aromaticities of these compounds were assessed by nucleus-independent chemical shift calculations, and 13C NMR chemical shifts were computed by gauge-inducing atomic orbital calculations. 1,4-DFBcPh and its dihydrodiol were subjected to metabolism, and the amount of DNA binding in human breast cancer MCF-7 cells was assessed. The extent of DNA binding was then compared with that for BcPh and its dihydrodiol and the potent carcinogen benzo[a]pyrene. The 1,4-DFBcPh series 2 (anti) diol epoxide-derived DNA adducts were also compared with those arising from intracellular oxidation of the dihydrodiol with subsequent DNA binding. These experiments showed that increased molecular distortion decreased metabolic activation to the terminal metabolites but that diol epoxide metabolites that are formed are the DNA-damaging species. 相似文献
77.
N. Kumar M. Graham S. K. Jha S. S. Chaturvedi 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):203-208
The understanding of the bio-geochemical behavior of the uranium radionuclides in the environmental matrices is crucial for
the health safety point of view. The research was carried out in munitions testing sites New Golloway (SW) of Scotland at
the Dunderann firing range which is contaminated with depleted uranium and site is particularly important because it provides
a controlled environment for the investigation of post depositional association of Depleted Uranium (DU) in contaminated soils.
This study used the modified BCR sequential extraction method to investigates the association of DU in at the different sampling
location and in a control soil and were followed by elemental analysis using inductively coupled-optical Emission spectroscopy
(ICP-OES).The Certified Reference Material (CRM) were used for the validation of the concentration. The concentrations of
(Bureau of Reference) BCR-extracted Uranium (U) were in the range of 4–40 (±13.2) mg kg−1 for the DU-contaminated sites whilst U was barely detectable in the soil from the control site (Rebury Gun) RGW. With the
exception of RGH and RGW, the values for BCR-extracted U compared well with those obtained using Aqaua-regia. The obtained
result showed that the maximum Uranium deposition is at RGE and it is 20 mg kg−1 before hitting the target, the 6 mg kg−1 at RGH and minimum is at RGG and RGW control site. 相似文献
78.
Atul Shrivastava Upma Chaturvedi Ravi Sonkar Ashok Kumar Khanna J. K. Saxena Gitika Bhatia 《Applied biochemistry and biotechnology》2012,167(2):229-236
Oxidative stress plays a major role in the pathogenesis of both types of diabetes mellitus. Excessively high levels of free radicals cause damage to cellular proteins, membrane lipids and nucleic acids, and eventually cell death. The present study was designed to investigate the possible effect of Azadirachta indica leaf extract in high fat diet induced diabetic Charles Foster rats. The increased level of lipidperoxidation and altered levels of enzymatic (superoxide dismutase, glutathione peroxidase and catalase) and non-enzymatic (glutathione) antioxidants were seen in high fructose fed animals. The treatment with A. indica leaf extract significantly normalized the altered levels of lipid peroxidation and antioxidant status at 400?mg/kg b.w. dose. The A. indica leaf extract was also tested for in vitro inhibition of generation of superoxide anion and hydroxyl free radical in both enzymatic and non-enzymatic systems. The A. indica leaf extract was found to inhibit generation of superoxide anion and hydroxyl free radical significantly at 200???g/ml concentration. Data of present study demonstrated that the A. indica leaf extract has both antidiabetic and antioxidant properties. 相似文献
79.
K. Chaturvedi Bipin Singh Koranga Vinod Kumar 《International Journal of Theoretical Physics》2012,51(2):622-628
Implication of the neutrino oscillation search for the neutrino mass square difference and mixing are discussed. We have considered
the effective Majorana mass m
ee
, related for ββ
0ν
decay. We find limits for neutrino mass eigen value m
i
in the different neutrino mass spectrum,which explain the different neutrino data. 相似文献
80.
We investigated a far-field superlens operating at mid-infrared wavelength that allows resolving subwavelength features in
the far-field. By utilizing evanescent enhancement provided by surface plasmon excitation of silver nanorods and Moiré effect,
we numerically demonstrated that subwavelength information of an object can be converted to propagating information. This
information can then be captured by conventional optical components. A simple image reconstruction algorithm can restore the
subwavelength object. A sub-diffraction-limited resolution of 2.5 μm at 6-μm wavelength is demonstrated. 相似文献