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81.
The Leishmania lipophosphoglycan (LPG) is the most abundant cell surface glycoconjugate of a family of infectious protozoa. Pentamidine, a common drug used in the treatment of Leishmania infections, has been modified with boronic acids so that it might bind more selectively to the phosphodisaccharide repeating unit of the LPG. This could serve to target the drug to the protozoan surface and increase its efficacy in vivo. 相似文献
82.
83.
Li C Lee D Graf TN Phifer SS Nakanishi Y Burgess JP Riswan S Setyowati FM Saribi AM Soejarto DD Farnsworth NR Falkinham JO Kroll DJ Kinghorn AD Wani MC Oberlies NH 《Organic letters》2005,7(25):5709-5712
[chemical reaction: see text]. Three new ent-trachylobane diterpenoids (1-3) were isolated and structures elucidated from Mitrephora glabra Scheff. (Annonaceae). Mitrephorone A (1) possesses a hexacyclic ring system with adjacent ketone moieties and an oxetane ring, both of which are unprecedented among trachylobanes. All compounds were evaluated for cytotoxicity against a panel of cancer cells, where 1 displayed the most potent and broadest activity, and against a battery of antimicrobial assays, where all compounds were approximately equipotent. 相似文献
84.
85.
B. Brocklehurst R.S. Dixon E.M. Gardy V.J. Lopata M.J. Quinn A. Singh F.P. Sargent 《Chemical physics letters》1974,28(3):361-363
Excited state formation by ion recombination in solutions of fluorene in squalene has been studied by pulse radiolysis at the center of a large electromagnet. The products of the slower part of the ion recombination are affected by an applied magnetic field. The fluorescence yield increases by a factor of about 1.5 whereas the triplet yield decreases. 相似文献
86.
A. S. Paschoa M. Cholewa K. W. Jones N. P. Singh M. E. Wrenn 《Journal of Radioanalytical and Nuclear Chemistry》1987,115(2):231-240
A combination of two techniques, PIXE (particle induced x-ray emission) and RBS (Rutherford backscattering), is proposed as an analytical tool to measure uranium and thorium in environmental and biological samples and in the study of the micro-distribution of uranium is low Z matrices such as biological tissue.Work supported by U.S. Department of Energy Contracts DE-AC02-76CH-00116 (MC, KWJ) and DE-AC02-76EV-00119 (NPS, MEW). One of us (ASP) is grateful to FINEP (Financiadora de Estudos e Projetos) and CNPq (Conselho Nacional de Desenvolvimento Cientifico e Technológico). 相似文献
87.
R. N. Singh S. Sujatha G. K. Mishra 《Journal of Radioanalytical and Nuclear Chemistry》1990,146(6):427-436
The distribution ratios for the extraction of Zr(IV) by TBP and its binary mixtures with DMSO or Py in n-dodecane in the presence of HNO3, and HClO4 have been determined. Based on stoichiometric and slope analysis methods a possible mechanism for the extraction has been proposed. 相似文献
88.
89.
L. Stachowicz S. K. Singh E. Wender S. L. Girshick 《Plasma Chemistry and Plasma Processing》1993,13(3):447-461
Heat-treated rice hulls have been used as precursor material for synthesis of ultrafne SiC in a RF plasma reactor. Rice hulls containing finely distributed silica and active carbon act as a source for SiC formation. The plasma-synthesized powder contained ultrafnc -SiC with excess carbon and some unreacted silica. Post-treatment processes such as oxidation and acid (HF) treatment appear to be effective in removing the excess carbon and silica. 相似文献
90.
Rabindra N. Roy Lakshmi N. Roy Jason G. Grant Mason P. Cummins Bennett J. Tabor III Sarah J. Richards Curtis A. Himes Bret R. Lively Penny L. Blackwell Ashley N. Simon 《Journal of solution chemistry》2002,31(11):861-872
The values of the second dissociation constant, pK
2, for the dissociation of the NH+ charge center of the zwitterionic buffer compounds 4-(N-morpholino)butanesulfonic acid (MOBS), and N-(2-hydroxyethyl)piperazine-N-4-butanesulfonic acid (HEPBS) have been determined from 5 to 55°C, including, 37°C at intervals of 5°C. The electromotive-force (emf) measurements have been made utilizing hydrogen electrodes and silver–silver chloride electrodes. The value of pK
2 for MOBS was found to be 7.702 ± 0.0005, and 8.284 ± 0.0004 for HEPBS, at 25°C, respectively. The related thermodynamic quantities, G
o, H
o, S
o, and C
p
o for the dissociation processes of MOBS and HEPBS have been derived from the temperature coefficients of pK
2. Both the MOBS and HEPBS buffer materials are useful as primary pH standards for the control of pH 7.3 to 8.6 in the region close to that of physiological fluids. 相似文献