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41.
[reaction: see text] Novel R- and S-spiro[2.3]hexane nucleosides have been synthesized. The key step involved the Pseudomonas cepacia lipase catalyzed resolution of racemic compound 2, synthesized in seven steps starting from diethoxyketene and diethyl fumarate, to give (+)-acetate 3 and (-)-alcohol 13. (+)-Acetate 3 and (-)-acetate 14 were converted to R- and S-9-(6-hydroxymethylspiro[2.3]hexane)-4-adenine, respectively. 相似文献
42.
Ranjeet Kumar J. R. Yadav D. D. Rao Lal Chand 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(3):787-790
Bioassay technique is used for the estimation of actinides present in the body based on the excretion rate of body fluids.
For occupational radiation workers urine assay is the preferred method for monitoring of chronic internal exposure. Determination
of low concentrations of actinides such as plutonium, americium and uranium at low level of mBq in urine by alpha-spectrometry
requires pre-concentration of large volumes of urine. This paper deals with standardization of analytical method for the determination
of U-isotopes in urine samples using anion-exchange resin and 232U tracer for radiochemical recovery. The method involves oxidation of urine followed by co-precipitation of uranium along
with calcium phosphate. Separation of U was carried out by Amberlite, IRA-400, anion-exchange resin. U-fraction was electrodeposited
and activity estimated using tracer recovery by alpha-spectrometer. Eight routine urine samples of radiation workers were
analyzed and consistent radiochemical tracer recovery was obtained in the range of 51% to 67% with a mean and standard deviation
of 60% and 5.4%, respectively. 相似文献
43.
We demonstrate simultaneous generation, propagation and detection of optical vortices using all fiber-optic system. A fiber-optic Y-coupler was used for generating spherical and doughnut beams, simultaneously. Gaussian (TEM00) beam emitted from CW red He-Ne laser is coupled into the fiber coupler and is converted into vortex beam via second arm of fiber which propagates with azimuthal phase dependence having well defined orbital angular momentum. The phase structure of vortex beam was detected by interfering both the beams using simple fiber-optic interferometer. The present all fiber-optic system might find application for detecting, sensing physical parameters and is simple and cost effective for generating and detecting optical vortices. 相似文献
44.
A facile, fluoride-induced transition-metal-free chemoselective α-arylation of β-dicarbonyl compounds (malonamide esters) at room temperature using aryne intermediates has been demonstrated. Selective mono- or diarylation and generation of a quaternary benzylic stereocenter have also been achieved. The methodology will be highly useful for the synthesis of a library of CNS depressant barbiturate drugs like Phenobarbital. 相似文献
45.
Ranjeet Kumar J. R. Yadav D. D. Rao 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(2):451-454
Bioassay technique is used for the estimation of actinides present in the body based on their excretion rate through body
fluids. For occupational radiation workers urine assay is the preferred method for monitoring of chronic internal exposure.
Determination of low concentrations of actinides such as plutonium, americium and uranium at low level of mBq in urine by
alpha spectrometry requires pre-concentration of large volumes of urine. This article deals with standardization of analytical
method for the determination of 241Am isotope in urine samples using Extraction Chromatography (EC) and 243Am tracer for radiochemical recovery. The method involves oxidation of urine followed by co-precipitation of americium along
with calcium phosphate. This precipitate after treatment is further subjected to calcium oxalate co-precipitation. Separation
of Am was carried out by EC column prepared by PC88-A (2-ethyl hexyl phosphonic acid 2-ethyl hexyl monoester) adsorbed on
microporous resin XAD-7 (PC88A-XAD7). Am-fraction was electro-deposited and activity estimated using tracer recovery by alpha
spectrometer. Ten routine urine samples of radiation workers were analyzed and consistent radiochemical recovery was obtained
in the range 44–60% with a mean and standard deviation of 51 and 4.7% respectively. 相似文献
46.
Ashok Ghoghari Ranjeet Dash Chandrakant Bhatt Kanchan Singh Anil Jha Harilal Patel Rahul Gupta Kevinkumar Kansagra Nuggehally R. Srinivas 《Biomedical chromatography : BMC》2016,30(12):1900-1907
A sensitive LC–MS/MS method was developed and validated for quantitation of saroglitazar using turboion spray interface with positive ion mode. A liquid–liquid extraction, with a mixture of dichloromethane and diethyl ether, was employed for the extraction of saroglitazar and glimepiride (IS) from human plasma. The chromatographic separation was achieved using an ACE‐5, C18 (4.6 × 100 mm) column with a gradient mobile phase comprising acetonitrile and ammonium acetate buffer with trifluoracetic acid in purified water. Both analytes were separated within 10 min with retention times of 4.52 and 2.57 min for saroglitazar and IS, respectively. Saroglitazar quantitation was achieved by the summation of two MRM transition pairs (m/z 440.2 to m/z 366.0 and m/z 440.2 to m/z 183.1), while that of IS was achieved using transition pair m/z 491.3 to m/z 352.0. The calibration standards of saroglitazar showed linearity from 0.2 to 500 ng/mL, with a lower limit of quantitation of 0.2 ng/mL. The biases for inter‐ and intra‐batch assays were ?7.51–1.15% and ?11.21 to ?3.25%, respectively, while the corresponding precisions were 5.04–8.06% and 1.53–7.68%, respectively. The developed method was used to monitor the plasma concentrations of saroglitazar in clinical samples. 相似文献
47.
Abu Hasnath Md Golam Sarwar Ranjeet Kumar Nirala Mohammed Arif Beena Khillare 《Natural product research》2015,29(12):1166-1169
This study was carried out to assess the spermicidal action of hexane extract from the fruits of Piper longum Linn. The sperm immobilisation studies showed that 20 mg/mL of hexane extract was able to immobilise sperms completely within 20 s. The sperm revival test revealed that the effects were spermicidal as sperm immobilisation effect was irreversible. There was also a significant reduction in sperm viability in the treated group in comparison to the control. The hypo-osmotic swelling of these sperms was significantly reduced, indicating that the hexane extract may probably cause injury to the sperm plasma membrane. Hence, this study showed that the hexane extract of P. longum possesses potential contraceptive spermicidal activity in vitro. 相似文献