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991.
992.
The effect of total solar eclipse on atmospheric conductivities has been studied. Continuous measurements of both types of
positive and negative electrical conductivities and some meteorological parameters in conjunction with the total solar eclipse
of 22 July, 2009 were made from 21 to 23 July, 2009 at Roorkee (29°52′ N, 77°53′ E, 275 m above sea level). Roorkee observed
90% maximum obscurity of eclipse since it was close to the path of totality. The event started from 05:28 AM IST and ended
at 07:42 AM IST with the total eclipse at 06:30 AM IST. Considerable increase of both positive and negative conductivities
were recorded during the eclipse with respect to those made on any other day. Increase in relative humidity and decrease in
temperature were also observed during the period of eclipse. 相似文献
993.
Shirazi Muhammad Faizan Wijesinghe Ruchire Eranga Ravichandran Naresh Kumar Kim Pilun Jeon Mansik Kim Jeehyun 《Optical Review》2017,24(2):219-225
Optical Review - A dual-path handheld system is proposed for cornea and retina imaging using spectral domain optical coherence tomography. The handheld sample arm is designed to acquire two images... 相似文献
994.
Rahul Kumar Manviri Rani Himanshu Gupta Daeryong Park 《International journal of environmental analytical chemistry》2017,97(7):637-656
This study reports the distribution of Cr, Ni, Cu and Pb in waters, sediments, macrophytes and fish of the Yamuna River’s patch in Delhi (India). This is one of the most polluted stretches of rivers in the world. Water from this river is used fosr irrigation, industrial and domestic purposes, including drinking water. The effects of season and anthropogenic practices were identified. Almost zero dissolved oxygen and high levels of lead and phosphate indicate the polluted state of the aquatic system. The enrichment factors in sediments (with respect to reference site) vary in the range of 0.60–82.9% (Cr), 1.40–90.5% (Ni), 1.00–85.3% (Cu) and 3.80–86.6% (Pb). The toxic effects due to Ni and Pb could frequently be visible in aquatic life as their values fall above the probable effect level (36 mg Kg?1 for Ni and 91.3 mg Kg?1 for Pb). The metal contents in the macrophyte (Eichhornia crassipes) and the fish (Oreochromis niloticus) generally increase in the summer season. Cu and Pb accumulate preferentially in E. crassipes. The fish from these waters is unsuitable for human consumption as the levels of Cr, Cu and Pb are above the recommended limits. Significant spatial variations in parameters of water and sediments were confirmed via one-way analysis of variance. The Pearson’s correlation analysis suggests a common source of some of the metals. Principal component analysis highlighted domestic, and industrial waste and coal-fired thermal power plants as the metal sources. This study might act as a benchmark for other investigations focused on similarly affected surface aquatic systems due to agricultural and industrial activities. 相似文献
995.
M.V. Madhubabu R. Shankar T. Krishna Y. Satish Kumar Y. Chiranjeevi Ch. Muralikrishna H. Rama Mohan Satish S. More M.V. Basaveswara Rao Raghunadh Akula 《Tetrahedron: Asymmetry》2017,28(12):1803-1807
A convergent approach towards the synthesis of the 2-alkyl-substituted tetrahydroquinoline alkaloid (?)-cuspareine via enantiospecific construction of the (R)-benzyl 2-formyl-3,4-dihydroquinoline-1(2H)-carboxylate. We have achieved an efficient enantiospecific synthesis of (?)-cuspareine starting from known key starting materials. The reactions employed for individual transformations are simple and high yielding, and the strategy could potentially be easily extended. 相似文献
996.
Novel chiral ionic liquids having chirality in their cationic part have been synthesized for evaluation of their catalytic potential as organocatalysts in sodium borohydride reduction of prochiral ketones to yield optically active secondary alcohols. The chiral ionic liquids have been synthesized from the reaction of (?)-menthol or (?)-borneol, chloroacetic acid and S-methyl/benzyl-2-mercaptobenzthiazole. The synthesized chiral ionic liquids have been characterized by 1H, 13C NMR and Mass spectrometry. Moderate to excellent enantiomeric excess (ee > 99%) has been obtained in asymmetric sodium borohydride reduction of prochiral ketones using these salts as chiral catalysts. 相似文献
997.
998.
Gurmessa Getahun Tadesse Singh Girija Shankar 《Research on Chemical Intermediates》2017,43(11):6447-6504
Research on Chemical Intermediates - Metal–carbenoids from α-diazocarbonyl compounds are well-known reactive intermediates with a long history of useful applications in synthetic organic... 相似文献
999.
Ratnakar N. Asolkar Ahilya Singh Paul R. Jensen William Aalbersberg Brad K. Carté Klaus-D. Feussner Ramesh Subramani Antonio DiPasquale Arnold L. Rheingold William Fenical 《Tetrahedron》2017,73(16):2234-2241
Six cytotoxic and antimicrobial metabolites of a new bromo-phenazinone class, the marinocyanins A-F (1–6), were isolated together with the known bacterial metabolites 2-bromo-1-hydroxyphenazine (7), lavanducyanin (8, WS-9659A) and its chlorinated analog WS-9659B (9). These metabolites were purified by bioassay-guided fractionation of the extracts of our MAR4 marine actinomycete strains CNS-284 and CNY-960. The structures of the new compounds were determined by detailed spectroscopic methods and marinocyanin A (1) was confirmed by crystallographic methods. The marinocyanins represent the first bromo-phenazinones with an N-isoprenoid substituent in the skeleton. Marinocyanins A-F show strong to weak cytotoxicity against HCT-116 human colon carcinoma and possess modest antimicrobial activities against Staphylococcus aureus and amphotericin-resistant Candida albicans. 相似文献
1000.