Geochemical characterization of miocene core sediments from Shahbazpur gas-wells (Bangladesh) in terms of elemental abundances by instrumental neutron activation analysis

Journal of Radioanalytical and Nuclear Chemistry - Geochemical characterization of Shahbazpur structure (Bengal Foredeep) in terms of elemental abundances obtained from INAA are presented by...     

Highly stereoselective synthesis of furano-oxepanes: intramolecular nitrone cycloaddition (INC) reactions on sugar derived 2-substituted allylic ethers

The stereoselective synthesis of furano-oxepanes has been achieved from sugar ethers by an intramolecular nitrone cycloaddition (INC) reaction. The substitution at the 2-position of the allylic group aided in the exclusive formation of oxepanes.     

A theoretical investigation of radiative effects and microphysical processes involved in the interaction of aerosol particulates in the atmosphere and validation of the theoretical results with the INDOEX observations

A theoretical approach, which is based on certain physical assumptions and quantum physical concepts, has been extended to investigate the radiative effects and the microphysical properties involved in the interaction of aerosol particulates in the atmosphere which may have important climatic effect. The theoretical findings are used to validate some of the observations of Indian Ocean Experiment (INDOEX) during its First Field Phase-98 (FFP-98) and Intense Field Phase-99 (IFP-99). The aerosol optical depth and the radiative forcing of the surface and the top of the atmosphere are computed and the results are found to have a good correspondence with the INDOEX results.     

Removal of radionuclides from low level radioactive liquid waste by precipitation

Six elements in several organs of mice fed with Zn deficient diet (Zn-def. mice) and those fed with control diet (control mice) were analyzed by INAA. Zinc concentrations in the organs of Zn-def. mice were not distinctly lower than those of control mice except for bone and pancreas. However, Ce content increased significantly in all organs of Zn-def. mice compared with control mice, indicating the partial substitution of Co with Zn in metal proteins or other materials for the Zn-def. mice.     

Preconcentration of phthalic acid esters in water samples by Saccharomyces cerevisiae immobilized on silica gel

A sensitive and selective column adsorption method is proposed for the off-line preconcentration and determination of phthalic acid esters (PAEs), namely benzyl-butyl phthalate (BBP), di-n-butyl phthalate (DBP) and di-cyclohexyl phthalate (DCHP). The PAEs was preconcentrated on Saccharomyces cerevisiae immobilized on silica gel and then determined by high performance liquid chromatography (HPLC). Several parameters on the recovery of the analytes were investigated. Recoveries of BBP, DBP and DCHP were 100±2, 98±2 and 98±3%, respectively, at 95% confidence level under optimum conditions. The detection limits (3S/N) of BBP, DBP and DCHP were 3.2, 6.3 and 3.1 μg l⁻¹, respectively. The capacity of the adsorbent was also examined and found to be 1.4 mg g⁻¹ for BBP and DBP, and 3.6 mg g⁻¹ for DCHP. S. cerevisiae immobilized on silica gel is suitable for repeated use without decreasing recovery up to about 25 adsorption-elution cycles. The proposed method was successfully applied to the determination of PAEs in river water with high precision and accuracy.     

The fluorescence properties of luteolines

The fluorescence properties of luteoline and its possible methyl ethers (a representative class of naturally occurring flavonoids) were investigated, together with the effect of diagnostic shift reagents such as sulfuric acid, aluminium trichloride, and borax. The results demonstrate that fluorimetry is a suitable tool for the identification and structure elucidation of minute samples of flavones, in particular if combined with absorption spectrometry. ThepK _a values of all trimethylethers were determined for the ground and first excited singlet states and related to the effects of basic reagents.

---

Die Fluoreszenzeigenschaften der Luteoline

Zusammenfassung Es wurden die Fluoreszenzeigenschaften der Luteoline (einer repräsentativen Klasse von natürlich vorkommenden Flavonoiden) sowie der Effekt diagnostischer Verschiebungsreagentien wie z. B. Schwefelsäure, Aluminiumtrichlorid und Borax untersucht. Die Ergebnisse zeigen, daß die Fluorimetrie eine geeignete Methode zur Identifikation und Strukturaufklärung auch geringster Probenmengen sein kann, besonders in Kombination mit Absorptionsmessungen. DiepK _s -Werte aller möglichen Trimethylether wurden für Grund- und ersten angeregten Zustand bestimmt und zu den Effekten der basischen Reagentien in Bezug gebracht.

     

Synthesis and Crystal Structure of Thiazolopyrimidine Derivatives: Insights into Weak Interactions

Crystallography Reports - Thiazolo[3,2-a]pyrimidines namely ethyl 2-acetyl-5-(2-fluorophenyl)-3,7-dimethyl-5H-thiazolo[3,2-a]pyrimidine-6-carboxylate 3a, ethyl...     

A study of redox properties of hydralazine hydrochloride,an antihypertensive drug

Hydralazine hydrochloride itself is a reducing agent and its redox properties like other reducing agents vary as the oxidizing agent and applied conditions vary. The redox properties of hydralazine were studied by spectrophotometric method. Formal redox potential of hydralazine was calculated and effect of pH was observed on redox properties of hydralazine.