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1.
2.
A simple, robust and sensitive sequential injection spectrophotometric method for the assay of penicillamine (PA) in pharmaceutical formulations is developed. The method was based on the complex formation when PA is reacted with iron(III) solution in hydrochloric acid media. The deep blue colored PA-iron(III) complex produced is monitored at a maximum wavelength of 600 nm. A five level orthogonal array design coupled to genetic algorithm was employed to obtain the optimum experimental conditions for the determination of PA using peak absorbance as the measure of the system's performance criterion. A linear dynamic range for the determination of PA of 25-300 ppm was obtained with a sampling frequency of 50 h−1 and a relative standard deviation of less than 0.98%. The method was successfully applied to the determination of PA in pharmaceutical formulations. 相似文献
3.
Alaa Eldin Mokhtar Abdel‐Hady 《国际化学动力学杂志》2013,45(11):712-720
The biological effect, aquation, and kinetics of oxidation of bis(2‐aminobenzothiazole)dichlorocobalt(II) complex by periodate in aqueous acidic solutions were studied. The complex exhibited a broad resistance toward the studied pathogens. The average value of the aquation constant was calculated spectrophotometrically as 2.55 × 10?5 mol2 dm?6. Kinetics of the oxidation reaction showed first‐order dependence on each reactant concentration and increased by increasing pH over the 3.80–4.80 range, 35–50°C, and decreased by increasing the ionic strength over the 0.1–0.5 mol dm?3 range. The polymerization of acrylonitrile was taken as an evidence for an inner‐sphere mechanism through the formation of free radical intermediates of Co(III) complexes, which were slowly converted to the final Co(III)products. 相似文献
4.
An ultrasound-assisted nanoscaled supramolecular coordination polymer (nanosized 1′ ) has been synthesized using a self-assembly reaction of K3[Cu (CN)4] and hexamethylenetetramine in the presence of Me3SnCl under ambient conditions. Nanosized 1′ was examined using elemental analysis, Fourier transform–infrared, transmission electron microscopy, scanning electron microscopy and X-ray powder diffractions. It was structurally compared with the single crystal supramolecular coordination polymer ∞3[Cu6(CN)7(C6H12N4)2(OH3)]; SCP 1. The photocatalytic activities of nanosized 1′ and SCP 1 toward different hazardous organic dyes were determined under ambient, UV-light irradiation and ultrasonic conditions. SCP 1 and nanosized 1′ as heterogeneous nanoparticles catalysts exhibited high catalytic activity for degradation of Congo Red, Methyl Violet 2B and Methylene Blue dyes. The effects of operational parameters on catalytic degradation process, identification of the degradation products and recycling of the catalyst were also investigated. SCP 1 and nanosized 1′ are recyclable heterogeneous catalysts and can be reused with efficient activities. The mechanism of degradation using different scavenger techniques iss proposed and discussed. The catalytic oxidation process is mainly caused by •OH radicals. 相似文献
5.
Ayman A. Ghfar Mohammad Magdy El-Metwally Mohamed Shaaban Sami A. Gabr Nada S. Gabr Marwa S. M. Diab Ahmad Aqel Mohamed A. Habila Wahidah H. Al-Qahtani Mohammad Y. Alfaifi Serag Eldin I. Elbehairi Bayan Ahmed AlJumah 《Molecules (Basel, Switzerland)》2021,26(9)
The anticancer activity of terretonin N (1) and butyrolactone I (2), obtained from the thermophilic fungus Aspergillus terreus TM8, was intensively studied against prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines. According to this study, both compounds showed potent cytotoxicity towards ovarian adenocarcinoma cells (SKOV3) with IC50 1.2 and 0.6 μg/mL, respectively. With respect to metastatic prostate cells (PC-3), the two compounds 1 and 2 showed a significantly promising cytotoxicity effect with IC50 of 7.4 and 4.5 μg/mL, respectively. The tested fungal metabolites showed higher rates of early and late apoptosis with little or no necrotic apoptotic pathway in all treated prostate adenocarcinoma (PC-3) and ovary adenocarcinoma (SKOV3) human cell lines, respectively. The results reported in this study confirmed the promising biological properties of terretonin N (1) and butyrolactone I (2) as anticancer agents via the induction of cellular apoptosis. However, further studies are needed to elucidate the molecular mechanism by which cellular apoptosis is induced in cancer cells. 相似文献
6.
<正>Two new eudesmane derivatives were isolated from the leaves and flowers of Verbesina virginica,along with the known 6-O-β-E -p-coumaroyl-4α-hydroxyeudesmane(1).Their structures were determined as 6-O-β-Z-p-coumaroyl-4α-hydroxyeudesmane(2) and 6-O-α-E-p-coumaroyl-1β-4α-dihydroxyeudesmane(3) by spectroscopic methods. 相似文献
7.
Alaa Eldin Mokhtar Abdel-Hady Rabie S. Farag Ahmad S. Abu-Khadra 《Transition Metal Chemistry》2010,35(5):571-576
The kinetics of oxidation of N,N-bis(salicylaldehyde-1,2-diaminoethane) cobalt(II) complex by N-bromosuccinimide (NBS) in aqueous acid and H2O–MeOH solvent mixtures were studied spectrophotometrically over the 20–40 °C range, 0.1–0.5 mol dm?3 ionic strength, 2.2–2.8 pH range and 0–40 wt% MeOH–H2O solvent mixtures for a range of NBS and complex concentrations. The rate shows first-order dependence on both [NBS] and [complex] and decreases with pH over the range studied. The protonated form of N-bromosuccinimide was identified as the main reactive species. An inner-sphere mechanism involving free radicals is proposed. 相似文献
8.
New Cytotoxic Laurene‐, Cuparene‐, and Laurokamurene‐Type Sesquiterpenes from the Red Alga Laurencia obtusa 下载免费PDF全文
Rihab F. Angawi Walied M. Alarif Rehab I. Hamza Farid A. Badria Seif‐Eldin N. Ayyad 《Helvetica chimica acta》2014,97(10):1388-1395
Three new sesquiterpene alcohols, laur‐2‐ene‐3,12‐diol ( 1 ), cuparene‐3,12‐diol ( 2 ), and 8,11‐dihydro‐1‐methoxylaurokamuren‐12‐ol ( 3 ), along with one known diterpene, kahukuen‐10‐ol ( 4 ) have been isolated from the organic extract of the red alga Laurencia obtusa. The chemical structures were elucidated on the basis of spectroscopic analysis. The cytotoxicity of the isolated compounds were evaluated against three cancer cell lines, i.e., KB, HepG2, and MCF‐7. Compound 4 exhibited a wide range of cytotoxic activity against KB, HepG2, and MCF‐7 cell lines with IC50 of 0.100, 0.057, and 0.054 μm, respectively. In addition, 1 showed moderate activities towards KB and MCF‐7 cell lines with IC50 values of 0.171 and 0.184 μM , respectively and 2 exhibited a moderate activity against KB cell line at a concentration of 0.213 μg/ml. On the other hand, compound 3 exhibited no cytotoxic activity against any of the three cell lines. 相似文献
9.
CM Thaker S Rayaprol Krushna Mavani DS Rana MS Sahasrabudhe SI Patil DG Kuberkar 《Pramana》2002,58(5-6):1035-1039
The effect of simultaneous substitution of a fluctuating cation and a divalent cation in LaMnO3 perovskite modifies the properties of the material to exhibit large valence colossal magnetoresistance (CMR) effect. A good
example of these properties is (La1−2x
Pr
x
Ca
x
)MnO3 (LPCMO) type CMR material. In this communication it is reported that, with the increase in x (for x=0.1, 0.15, 0.2), the T
c varies between 100 and 120 K with improvisation in metal-insulator transition. Interestingly, resistance increases with x from few hundred ohms to few kilo ohms with corresponding decrease in the unit cell volume. The results of the studies using
X-ray diffraction (XRD), electrical resistivity, magnetoresistance and ac susceptibility measurements on LPCMO samples for
understanding the structural, transport and magnetic properties are discussed in detail. 相似文献
10.
John W.Grove 《数学物理学报(B辑英文版)》2010,30(2):563-594
This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described. 相似文献