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61.
In this paper we characterize all prime and primary submodules of the free R-module R
n
for a principal ideal domain R and find the minimal primary decomposition of any submodule of R
n
. In the case n = 2, we also determine the height of prime submodules. 相似文献
62.
Khaldun M. Al Azzam Ahmad Makahleah Bahruddin Saad Sharif M. Mansor 《Journal of chromatography. A》2010,1217(23):3654-3659
A three-phase hollow fiber liquid-phase microextraction (HF-LPME) coupled either with capillary electrophoresis (CE) or high performance liquid chromatography (HPLC) with UV detection methods was successfully developed for the determination of trace levels of the anti-diabetic drug, rosiglitazone (ROSI) in biological fluids. The analyte was extracted into dihexyl ether that was immobilized in the wall pores of a porous hollow fiber from 10 mL of aqueous sample, pH 9.5 (donor phase), and was back extracted into the acceptor phase that contained 0.1 M HCl located in the lumen of the hollow fiber. Parameters affecting the extraction process such as type of extraction solvent, HCl concentration, donor phase pH, extraction time, stirring speed, and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; donor phase pH, 9.5; acceptor phase, 0.1 M HCl; stirring speed, 600 rpm; extraction time, 30 min; without addition of salt), enrichment factor of 280 was obtained. Good linearity and correlation coefficients of the analyte was obtained over the concentration ranges of 1.0–500 and 5.0–500 ng mL−1 for the HPLC (r2 = 0.9988) and CE (r2 = 0.9967) methods, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for the HPLC and CE methods were (0.18, 2.83) and (0.56, 5.00) ng mL−1, respectively. The percent relative standard deviation (n = 6) for the extraction and determination of three concentration levels (10, 250, 500 ng mL−1) of ROSI using the HPLC and CE methods were less than 10.9% and 13.2%, respectively. The developed methods are simple, rapid, sensitive and are suitable for the determination of trace amounts of ROSI in biological fluids. 相似文献
63.
Maik Dreyer Dr. Daniel Cruz Dr. Ulrich Hagemann Dr. Patrick Zeller Dr. Markus Heidelmann Dr. Soma Salamon Dr. Joachim Landers Anna Rabe Dr. Klaus Friedel Ortega Dr. Sharif Najafishirtari Prof. Dr. Heiko Wende Prof. Dr. Nils Hartmann Dr. Axel Knop-Gericke Prof. Dr. Robert Schlögl Prof. Dr. Malte Behrens 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):17127-17144
Perovskites are interesting oxidation catalysts due to their chemical flexibility enabling the tuning of several properties. In this work, we synthesized LaFe1−xCoxO3 catalysts by co-precipitation and thermal decomposition, characterized them thoroughly and studied their 2-propanol oxidation activity under dry and wet conditions to bridge the knowledge gap between gas and liquid phase reactions. Transient tests showed a highly active, unstable low-temperature (LT) reaction channel in conversion profiles and a stable, less-active high-temperature (HT) channel. Cobalt incorporation had a positive effect on the activity. The effect of water was negative on the LT channel, whereas the HT channel activity was boosted for x>0.15. The boost may originate from a slower deactivation rate of the Co3+ sites under wet conditions and a higher amount of hydroxide species on the surface comparing wet to dry feeds. Water addition resulted in a slower deactivation for Co-rich catalysts and higher activity in the HT channel state. 相似文献
64.
Masood Parvez Sumaira Umbreen Farzana Latif Ansari 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):o298-o301
In the structures of 2‐(4‐chlorophenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐dihydro‐1,5‐benzothiazepine, C21H16ClNOS, 4‐(2‐hydroxyphenyl)‐2‐(4‐tolyl)‐2,3‐dihydro‐1,5‐benzothiazepine, C22H19NOS, and 4‐(2‐hydroxyphenyl)‐2‐(3‐methoxyphenyl)‐2,3‐dihydro‐1,5‐benzothiazepine, C22H19NO2S, the central seven‐membered heterocyclic rings adopt twist‐boat conformations in which the N atoms are involved in strong intramolecular hydrogen bonds with the hydroxyl H atoms, resulting in six‐membered rings. 相似文献
65.
We analyze the role of the electromagnetic field for the stability of a shearing viscous star with spherical symmetry. Matching conditions are given for the interior and the exterior metrics. We use a perturbation scheme to construct the collapse equation. The range of instability is explored in Newtonian and post Newtonian (pN) limits. We conclude that the electromagnetic field diminishes the effects of the shearing viscosity in the instability range and makes the system more unstable in both Newtonian and post Newtonian approximations. 相似文献
66.
Alharbi F. F. Aman Salma Ahmad Naseeb Ejaz Syeda Rabia Khosa Rabia Yasmin Abid Abdul Ghafoor Manzoor Sumaira Al-Buriahi M. S. Alrowaili Z. A. Farid Hafiz Muhammad Tahir 《Journal of Solid State Electrochemistry》2022,26(5):1251-1258
Journal of Solid State Electrochemistry - Scientists are increasingly interested in improving electroactive technologies for supercapacitor applications, since energy storage devices have improved... 相似文献
67.
A simple and efficient method for the synthesis of 9,9‐dimethyl‐9,10‐dihydro‐8H‐benzo‐[α]xanthen‐11(12)‐one derivatives (DDBXs) was developed by the condensation reaction of various substituted aryl al... 相似文献
68.
Suhanya Parthasarathy Surash Ramanathan Sabariah Ismail Mohd Ilham Adenan Sharif Mahsufi Mansor Vikneswaran Murugaiyah 《Analytical and bioanalytical chemistry》2010,397(5):2023-2030
A new solid phase extraction method for rapid high performance liquid chromatography–UV determination of mitragynine in plasma
has been developed. Optimal separation was achieved with an isocratic mobile phase consisting of acetonitrile–ammonium acetate
buffer, 50 mM at pH 5.0 (50:50, v/v). The method had limits of detection and quantification of 0.025 and 0.050 μg/mL, respectively.
The method was accurate and precise for the quantitative analysis of mitragynine in human and rat plasma with within-day and
between-day accuracies between 84.0 and 109.6%, and their precision values were between 1.7 and 16.8%. Additional advantages
over known methods are related to the solid phase extraction technique for sample preparation which yields a clean chromatogram,
a short total analysis time, requires a smaller amount of plasma samples and has good assay sensitivity for bioanalytical
application. The method was successfully applied in pharmacokinetic and stability studies of mitragynine. In the present study,
mitragynine was found to be fairly stable during storage and sample preparation. The present study showed for the first time
the detailed pharmacokinetic profiles of mitragynine. Following intravenous administration, mitragynine demonstrated a biphasic
elimination from plasma. Oral absorption of the drug was slow, prolonged and was incomplete, with a calculated absolute oral
bioavailability value of 3.03%. The variations observed in previous pharmacokinetic studies after oral administration of mitragynine
could be attributed to its poor bioavailability rather than to the differences in assay method, metabolic saturation or mitragynine
dose. 相似文献
69.
70.
Ajeet Kaushik Pratima R. Solanki Keiichi Kaneto C. G. Kim Sharif Ahmad Bansi D. Malhotra 《Electroanalysis》2010,22(10):1045-1055
A nanostructured iron oxide (NanoFe3O4, particle size ca. 25 nm and roughness ca. 21 nm) film deposited onto a hydrolyzed indium‐tin‐oxide (ITO) coated glass plate has been used to immobilize cholesterol oxidase (ChOx) to fabricate an impedimetric cholesterol sensor. Electrochemical studies reveal that surface charged Fe3O4 nanoparticles provide better conformation for ChOx loading resulting in enhanced electron transfer between ChOx and the electrode. Impedimetric response studies of the ChOx/NanoFe3O4/ITO bioelectrode exhibit improved linearity (2.5–400 mg/dL), low detection limit (0.25 mg/dL), fast response time (25 s), high sensitivity (86 Ω/mg dL?1/cm?2) and a low value of the Michaelis‐Menten constant (Km, 0.8 mg/dL) with a regression coefficient of 0.997. 相似文献