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51.
Karishna C. Joshi Anshu Dandia Sunita Baweja Amitabh Joshi 《Journal of heterocyclic chemistry》1989,26(4):1097-1099
An elegant one-step synthesis of two novel spiro ring systems viz: spiro[3H-indole-3,4′-(2′-amino-3′-carbonitrile-[4′H]-pyrano[3,2-c]benzopyran)]-2,5′(1H)-dione8 and spiro[(2-amino-3-carbonitrile-indeno[1,2-b]pyran)-4(5H)>3′-[3H]indole]-2′,5(1′H)-diones in 80–85% yields is described. The spiro heterocycles were prepared by the reactions of fluorine containing 3-dicyanomethylene-2H-indol-2-ones with 4-hydroxy-2H-1-benzopyran-2-one and 1H-indene-1,3(2H)-dione respectively. The synthesized compounds have been characterized on the basis of elemental analyses, ir, pmr, 19F nmr and mass spectral data. 相似文献
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M. K. Joshi 《Fresenius' Journal of Analytical Chemistry》1957,157(4):264-266
Summary Oxidation of thiocyanate by standard permanganate using electrometric end points is shown to be quantitative in 1.5–2.5N HCl medium and in the presence of ICl as catalyst. A method of estimating cerium(IV), based upon its reduction to cerium(III) by excess KSCN and potentiometric titration of the excess against KMnO4, is also described.Sincere thanks of the author are due to Prof. S. S. Joshi for research facilities. 相似文献
54.
Direct titration of thiocyanate with standard potassium iodate solution is found to yield accurate results in a final hydrochloric acid concentration regulated between 1.5 and 3N. The end-point is determined either potentiometrically or with carbon tetrachloride indicator. 相似文献
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Ranjit Joshi Jörg Friedrich Santosh Krishna-Subramanian 《Plasma Chemistry and Plasma Processing》2013,33(5):921-940
Ultra-high molecular weight polyethylene membranes were modified and subsequently polymer coated using the underwater plasma produced by glow discharge electrolysis. This plasma pretreatment generated various O-functional groups among them OH groups have dominated. This modified inner (pore) surface of membranes showed complete wetting and strong adhesion to a hydrogel copolymerized by glow discharge electrolysis also. The deposited hydrogel consists of plasma polymerized acrylic acid crosslinked by copolymerization with the bifunctional N,N′-methylenebis(acrylamide). Tuning the hydrogel hydrophilicity and bio-compatibility poly(ethylene glycol) was chemically inserted into the copolymer. Such saturated polymer could only be inserted on a non-classic way by (partial) fragmentation and recombination thus demonstrating the exotic properties of the underwater plasma. The modification of membrane was achieved by squeezing the reactive plasma solution into the pores by plasma-induced shock waves and supported by intense stirring. The deposited copolymer hydrogel has filled all pores also in the inner of membrane as shown by scanning electron microscopy of cross-sections. The copolymer shows the characteristic units of acrylic acid and ethylene glycol as demonstrated by infrared spectroscopy. A minimum loss in carboxylic groups of acrylic acid during the plasma polymerization process was confirmed by X-ray photoelectron spectroscopy. Additional cell adhesion tests on copolymer coated polyethylene using IEC-6 cells demonstrated the bio-compatibility of the plasma-deposited hydrogel. 相似文献
57.
An aqueous aza-Michael reaction is efficiently achieved with excellent conversions without any additives. The method works very well on a molar scale with selectively for aliphatic amines. An intermediate for spermine is also made by this green process. 相似文献
58.
R. M. Joshi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):1309-1383
Abstract The new generalized bond energy scheme has been extended to organic oxygen compounds. About 50 different types of bonds have been identified and their ΔHf°(g) contributions and atomization energies evaluated by a procedure similar to multilinear regression analysis. Recent thermochemical data (1969-1973) on 145 oxygen compounds and about 80 ring compounds have been employed to test the efficiency of the scheme in predicting the gas phase heats of formation. This was found to be about ±0. 8 kcal/mole, which is quite comparable to the group contribution method of Benson and co-workers involving a much larger number of parameters. The typical chemical bonds identified and resolved in respect of their bond energies bear good consistency and correlation with bond lengths and force constants measurable independently. Heats of formation and polymerization on about 47 monomer-polymer systems and enthalpies of other polymeric reactions have been predicted and compared with available experimental data. 相似文献
59.
Conductivity as a Sensor for Monitoring Relative Magnesium Corrosion Rates in Real‐time,in Serum‐containing Media under Cell Culture Conditions
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Kolade Ojo Tracy Hopkins Madhura Joshi Pravahan Salunke Guangqi Zhang Keaton Nahan Zhannping Zhang Daoli Zhao Sarah K. Pixley Vesselin Shanov William R. Heineman 《Electroanalysis》2016,28(12):3000-3008
Because controlling the corrosion rate of magnesium metal will be crucial to the success of biomedical implants containing pure magnesium or magnesium alloys, many ways have been sought to improve in vitro tests to analyze corrosion rates, and also to identify new methods of preparing or post‐processing magnesium. In this work, for an in vitro assay, we explored the use of a commercially available conductivity sensor to study magnesium corrosion under cell culture conditions that duplicate many physiologically appropriate parameters. With this sensor, we studied the corrosion of two previously untested magnesium single crystal samples that differed in surface treatments that could alter corrosion rates. The results show that the relative conductivity changes in (mS/cm) over the total time of immersion were proportional to the corrosion rates in (mm/y) and also to the total magnesium released, as detected by inductively coupled plasma mass spectrometry (ICP‐MS). 相似文献
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