排序方式: 共有216条查询结果,搜索用时 187 毫秒
11.
12.
Gholam Hossein Zohuri Saman Damavandi Reza Sandaroos 《Research on Chemical Intermediates》2013,39(5):2115-2121
A new and efficient method has been developed for the one-pot synthesis of novel 2,9-dihydro-2-oxo-4-aryl-1H-pyrido[2,3-b]indole-3-carbonitrile derivatives by condensation of substituted (triethoxymethyl)arene, 1-methyl-1H-indol-2-ol and cyanoacetamide in the presence of a catalytic amount of crosslinked poly(2-acrylamido-2-methyl propane sulfonic acid) (AMPS) as an efficient and heterogeneous catalyst. This polymeric solid acid catalyst is stable and can be easily recovered and reused without significant change in its activity. 相似文献
13.
Asma Hayat Shazia Bashir Muahmamd Shahid Rafique Mahreen Akram Khaliq Mahmood Saman Iqbal Asadullah Dawood Arooj 《Optics and Spectroscopy》2016,120(1):1-8
The optical characteristics of biological tissues sampled from the anterior abdominal wall of laboratory rats are for the first time experimentally studied in a wide wavelength range (350-2500 nm). The experiments have been performed in vitro using a LAMBDA 950 (PerkinElmer, United States) spectrophotometer. Inverse Monte Carlo simulation is used to restore the spectral dependences for scattering and absorption coefficients, as well as the scattering anisotropy factor for biological tissue based on the recorded spectra of diffuse reflection and total and collimated transmissions. 相似文献
14.
Mohammad Reza Hadjmohammadi S. Saman S. J. Nazari 《Journal of separation science》2013,36(23):3667-3672
The simultaneous isocratic separation of a mixture of five phenolic acids and four flavonoids (two important groups of natural polyphenolic compounds with very different polarities) was investigated in three different RPLC modes using a hydro‐organic mobile phase, and mobile phases containing SDS at concentrations below and above the critical micellar concentration (submicellar LC and micellar LC (MLC), respectively). In the hydro‐organic mode, methanol and acetonitrile; in the submicellar mode methanol; and in the micellar mode, methanol and 1‐propanol were examined individually as organic modifiers. Regarding the other modes, MLC provided more appropriate resolutions and analysis time and was preferred for the separation of the selected compounds. Optimization of separation in MLC was performed using an interpretative approach for each alcohol. In this way, the retention of phenolic acids and flavonoids were modeled using the retention factors obtained from five different mobile phases, then the Pareto optimality method was applied to find the best compatibility between analysis time and quality of separation. The results of this study showed some promising advantages of MLC for the simultaneous separation of phenolic acids and flavonoids, including low consumption of organic solvent, good resolution, short analysis time, and no requirement of gradient elution. 相似文献
15.
[reaction: see text] A simple and efficient two-step approach to spiroketals is described. Key steps include the preparation of functionalized hydroxyl alpha-alkynones by ring-opening reactions of lactones with lithium alkynyltrifluoroborates followed by a palladium-catalyzed hydrogenation/spirocyclization of the prespiroketal intermediate. 相似文献
16.
17.
Saman Azodi-Deilami Majid Abdouss Seyed Alireza Hasani 《Central European Journal of Chemistry》2010,8(4):861-869
In this paper, a highly selective molecularly imprinted polymer (MIP) for tramadol hydrochloride, a drug used to treat moderate
to severe pain, was prepared and its use as solid-phase extraction (SPE) sorbent was demonstrated. The molecularly imprinted
solid-phase extraction procedure followed by high performance liquid chromatography with ultraviolet detector (MISPE-HPLC)
was developed for selective extraction and determination of tramadol in human plasma and urine. The optimal conditions for
molecularly imprinted solid-phase extraction (MISPE) consisted of conditioning with 1 mL methanol and 1 mL of deionized water
at neutral pH, loading of tramadol sample (50 μg L−1) at pH 7.5, washing using 1 mL acetone and elution with 3 × 1 mL of 10% (v/v) acetic acid in methanol. The MIP selectivity
was evaluated by checking several substances with similar molecular structures to that of tramadol. Results from the HPLC
analyses showed that the calibration curve of tramadol (using MIP from human plasma and urine) is linear in the ranges of
6–100 and 3–120 μg L−1 with good precisions (1.9% and 2.9% for 5.0 μg L−1), respectively. The recoveries for plasma and urine samples were higher than 81%.
相似文献
18.
A phase conjugation algorithm for localizing the spatial support of an extended radiating current source from boundary measurements of the electric field over a finite set of frequencies is presented. An imaging function using a full frequency bandwidth is established and analyzed. It is subsequently adopted to the case of finite frequency measurements. Finally, the algorithm is blended with l1-regularization in order to deal with the artifacts associated with finite frequency data. 相似文献
19.
20.