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Abstract  

A single crystal of sodium and potassium cinnamates was grown by slow evaporation of methanol solution at room temperature. The effect of metals sodium and potassium on the electronic structure of cinnamic acid was studied. In this research many analytical methods such as FTIR, UV, second harmonic generation (SHG) and TG–DTA were used: The spectroscopic studies lead to conclusions containing the distribution of the electronic charge in molecule, the delocalisation of π electrons and the reactivity of metal complexes. The SHG efficiency is more pronounced in the presence of sodium and potassium dopant in the growth medium. Incorporation of sodium and potassium increase the thermal stability ensuring the suitability of material for possible non-linear optical (NLO) application up to 180 °C.

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Abstract  

A single crystal of urea–thiourea was grown by slow evaporation of aqueous solution at room temperature. The bright and transparent crystals obtained were characterised by TG–DTA, UV and FTIR spectral analyses. A fitting decomposition pattern for the title compound was formulated on the TG curve which shows a two stage mass loss between 200 and 750 °C. DTA curve shows exothermic peaks supporting the formulated decomposition pattern in this temperature range. The UV and FTIR spectra show the characteristic absorption, vibration frequencies due to urea–thiourea zinc chloride crystals. Detailed structural analysis of the compound is under progress.

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Abstract  

A mixed crystal of urea–thiourea was grown by slow evaporation of aqueous solution at room temperature. The bright and transparent crystals obtained were characterized by thermogravimetric–differential thermal analysis (TG–DTA), UV and FTIR spectroscopic analyses. A fitting decomposition pattern for the title compound was formulated on the TG curve which shows a two stage weight loss between 200 and 750 °C. In this temperature range DTA curve shows exothermic peaks supporting the formulated decomposition pattern. The UV and FTIR spectra show the characteristic absorption, vibration frequencies due to urea–thiourea mixed crystals. Detailed structural analysis of the compound is under progress.

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The present study was aimed to investigate the effect of different ultraviolet radiation doses on the growth, and antioxidant enzymes of three cultivars of soybean ( Glycine max L.) (‘Giza-22’, ‘Giza-35’ and ‘Giza-111’). The seeds were grown in plastic pots equally filled with a mixture of pre-sieved sandy loam soil, peat-moss and vermiculite (2: 1: 1) for two weeks. The planted pots were divided into four groups and exposed to white light (1,100 Lux) (control), 3.2, 6.4 and 12.8 KJ m −2 d −1 UV A+B radiation, respectively, for 30 days and then harvested. The results indicated that shoot dry weight was decreased with increasing UV A+B radiation doses; it was found that supplementation of UV A+B radiation increased root dry weight in all studied cultivars of soybean plants. With referring to oxidative stress, it was found that increasing UV radiation induced significant increases in H 2 O 2 concentration, lipid peroxidation and cell death (as ion leakage) in soybean cultivars. Increasing supplemental doses of ultraviolet radiations significantly induced reductions in all studied antioxidants (catalase, peroxidase and superoxide dismutase (SOD) activities and glutathione content).

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Summary

Ezetimibe is the first in a new class of antihypercholesterolemic drugs. Since it has not long been available on the market, many of its properties may still be revealed. Analytical methods for its determination are scarce, especially regarding serum samples. A simple, fast, and effective high-performance liquid chromatography-ultraviolet (HPLC-UV) method for the determination of ezetimibe concentration in human serum has therefore been developed. Three mobile phases were analysed, and original modifications to the concentration and flow parameters were made. Of five potential internal standards (IS), only nitrendipine was found to be suitable. The analytical wavelength was chosen based on the absorption spectrum of ezetimibe in the mobile phase. Finally, an extraction analysis was performed using two different solvents, and the extrahent volume was optimised. The final method developed was as follows. Single extraction of 1 mL serum sample, spiked with IS, was performed using 10 mL of methyl-t-butyl ether. Separation was obtained at ambient temperature on a Waters C18 Symmetry Shield (4.6 mm × 250 mm, 5 μm) column. The isocratic mobile phase was composed of acetonitrile and 0.1 M ammonium acetate aqueous solution 55:45 (v/v), set at flow rate of 0.75 mL min−1. Ezetimibe was detected at a wavelength of 232 nm after 5.49 min, and the IS was detected at 8.05 min. The developed method has been validated according to ICH standards. It was found to be specific, precise, accurate and linear over the range 10–800 ng mL−1 with R 2 > 0.998, and detection and quantification limits of 4.60 ng mL−1 and 13.94 ng mL−1, respectively. The method has been applied to clinical serum samples. The developed technique allowed for successful in vivo assessment of ezetimibe concentrations in samples obtained from hypercholesterolemia patients who are chronically receiving the drug.

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Acta Biologica Hungarica
Authors: Ivanka Fedina, Maya Velitchkova, Katya Georgieva, Dimitrina Nedeva, and H. Çakırlar

Adamse, P., Britz, S. J. (1992) Amelioration of UV-B damage under high irradiance. I. Role of photosynthesis. Photochem. Photobiol. 56 , 645–650. Britz S. J

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substrates by quenching the conduction band electrons and form reactive radical intermediates [ 5 – 7 ]. These oxidants increase the effectiveness of UV/photocatalyst in degrading organic substrates by capturing the electrons that are ejected from the

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, UV, and XRD detection and infrared imaging. A transition metal has an incomplete d -subshell; it can give rise to cations with an incomplete d subshell. All the transition metals (including Fe 2+ ) have the same arrangement of outer

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Journal of Thermal Analysis and Calorimetry
Authors: B. Ravindran, G. Madhurambal, M. Mariappan, K. Ramamurthi, and S. C. Mojumdar

in literature regarding the study of mercury cinnamate. This article reports the synthesis and characterization of mercury cinnamate using UV and FTIR spectral and TG and DTA studies. A detailed structural analysis of the compound is under progress

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Demchik, S. M., Day, T. A. (1996): Effect of enhanced UV-B radiation on pollen quantity, quality and seed yield in Brassica rapa (Brassicaceae). Am. J. Bot. , 83 , 573–579. Day T. A

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