Modified alpha-beta chimeric oligoDNA bearing a multi-conjugate of 2,2-bis(hydroxymethyl)propionic acid-anthraquinone-polyamine exhibited improved and stereo-nonspecific triplex-forming ability

Novel alpha-beta chimeric oligonucleotides bearing a propionic acid derivative of an anthraquinone-polyamine conjugate in the "linker" region sequence-specifically formed a substantially stable alternate-stranded triplex with dsDNA almost regardless of the stereochemistry of the derivative.     

Effect of citric acid concentration as emulsifier on perovskite phase formation of nano‐sized SrMnO3 and SrCoO3 samples

In this study the effects of citric acid concentration, used as organic emulsifier, on the perovskite phase formation of the nano strontium manganite or cobaltite samples were studied. Stoichiometric perovskites in the absence and presence of citric acid were prepared by drying a solution containing molar ratio of Sr(NO₃)₂/Mn(NO₃)₂·4H₂O and Sr(NO₃)₂/Co(NO₃)₂·6H₂O = 1 followed by calcination at 900 °C for 5 h. Citric acid concentration, selected to be 0.0, 0.3, 0.6, 1.0, 1.3, 2.5 and 5 times of the total number of moles of the nitrate ions. The results revealed that increase in the citric acid concentration, larger than number of moles of the nitrate ions equivalent, deteriorates the perovskite phase formation. Instead, a new phase of carbonates and metal oxides are appeared. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Easily manufactured TiO2 hollow fibers for quantum dot sensitized solar cells

TiO(2) hollow fibers with high surface area were manufactured by a simple synthesis method, using natural cellulose fibers as template. The effective light scattering properties of the hollow fibers, originating from their micron size, were observed by diffuse reflectance spectroscopy. In spite of the micrometric length of the TiO(2) hollow fibers, the walls were highly porous and high surface area (78.2 m(2) g(-1)) was obtained by the BET method. TiO(2) hollow fibers alone and mixed with other TiO(2) pastes were sensitized with CdSe quantum dots (QDs) by Successive Ionic Layer Adsorption and Reaction (SILAR) and integrated as a photoanode in quantum dot sensitized solar cells (QDSCs). High power conversion efficiency was obtained, 3.24% (V(oc) = 503 mV, J(sc) = 11.92 mA cm(-2), FF = 0.54), and a clear correspondence of the cell performance with the photoanode structure was observed. The unique properties of these fibers: high surface area, effective light scattering, hollow structure to facile electrolyte diffusion and the rather high efficiencies obtained here suggest that hollow fibers can be introduced as promising nanostructures to make highly efficient quantum dot sensitized solar cells.     

Oxidative coupling of methane over （Na2WO4＋Mn or Ce）/SiO2 catalysts： In situ measurement of electrical conductivity

The effects of manganese oxide or ceria promoters on the performance of Na2WO4/SiO2 catalysts for oxidative coupling of methane (OCM) are reported. The OCM reaction was performed in a continuous-flow microreactor at 800 ℃, atmospheric pressure and under GHSV = 13200 ml gC-1at h-1. Catalysts were characterized by in situ conductivity measurement, FT-IR spectroscopy, XRD, SEM and temperature programmed reduction analysis. Manganese oxide promoted Na2WO4/SiO2 is considered as one of the active and selective ca...     

Determination of Furosemide by Simple Diazotization Method in Pharmaceutical Preparations

A simple and rapid spectrophotometric method has been investigated for the determination of furosemide. The method is based upon simple diazotization reaction. The absorbance was measured at 480 nm. The method is optimized for acidity, amount of reagents required and heating time. The range of linearity was 0.4–10 μg mL^?1 of furosemide with molar absorptivity of 1.0 × 10⁴ l mol^?1 cm^?1. Standard deviation, coefficient of variance, limit of detection and limit of quantification were calculated using authentic standard of furosemide and were found to ± 0.0013,12.7%, 0.16 ppm and 0.52 ppm, respectively. The method was applied to various pharmaceutical preparations containing furosemide. The results of the investigated method for furosemide were compared with available official literature method. The results obtained by the proposed method agree well with the standard established method.     

Consensus QSAR models estimating acute toxicity to aquatic organisms from different trophic levels: algae,Daphnia and fish

ABSTRACT

We report new consensus models estimating acute toxicity for algae, Daphnia and fish endpoints. We assembled a large collection of 3680 public unique compounds annotated by, at least, one experimental value for the given endpoint. Support Vector Machine models were internally and externally validated following the OECD principles. Reasonable predictive performances were achieved (RMSE_ext = 0.56–0.78) which are in line with those of state-of-the-art models. The known structural alerts are compared with analysis of the atomic contributions to these models obtained using the ISIDA/ColorAtom utility. A benchmarking against existing tools has been carried out on a set of compounds considered more representative and relevant for the chemical space of the current chemical industry. Our model scored one of the best accuracy and data coverage.

Nevertheless, industrial data performances were noticeably lower than those on public data, indicating that existing models fail to meet the industrial needs. Thus, final models were updated with the inclusion of new industrial compounds, extending the applicability domain and relevance for application in an industrial context. Generated models and collected public data are made freely available.     

Removal and Recovery of UO2(??) from Water Samples Using 2,2′‐Diamino‐4,4′‐bithiazole as a New Reagent for Solid Phase Extraction

A novel sensitive and simple method for rapid and selective extraction, preconcentration and determination of uranyl as its 2,2′‐diamino‐4,4′‐bithiazole (DABTZ) complex by using octadecylsilica columns and spectrophotometry is presented. Extraction efficiency and the influence of flow rates of sample solution and eluent, pH, amount of DABTZ, type and least amount of eluent for elution of uranyl complex from columns, break‐through volume and limit of detection were evaluated. Also the effects of various cationic and anionic interferences on percent recovery of uranyl were studied. Average extraction efficiency of ca. 90% was obtained by elution of the column with minimal amount of solvent in the presence of interferences. The average preconcentration factor, 136 and a detection limit 0.32 ng·mL^?1 were obtained. The method was applied to the recovery and determination of uranyl in different water samples.     

CuO-CeO2 nanocomposite：A highly efficient recyclable catalyst for the multicomponent synthesis of 4H-benzo[b]pyran derivatives

CuO–CeO2 is reported as a highly efficient and green recyclable catalyst,for the multicomponent synthesis of 4H-benzo[b]pyran derivatives.The catalyst was synthesized by a co-precipitation method and characterized by XRD,BET specific surface area,ESEM and EDS analysis.This synthetic method provides several advantages such as simple work-up procedures,minimal amount of waste generated,short reaction time,and high yields of products.     

A spectrophotometric method for quantitative determination of lactulose in pharmaceutical preparations

A simple spectrophotometric assay for the quantification of lactulose in pharmaceutical preparations was developed. The method is based on hydrolysis of lactulose under acidic conditions. The hydrolyzed product reacts with resorcinol, giving absorption peaks at 398 and 480 nm. Both absorption wavelengths can be used for the determination of lactulose. The limit of detection of lactulose at 398 nm and 480 nm was 0.075 μg mL⁻¹ and 0.65 μg mL⁻¹, respectively. The calibration was linear in the range of 5–25 μg mL⁻¹. Analytical conditions were optimized, and the method was validated for analysis of pharmaceutical preparations. The determined amount of lactulose was found to be in good agreement with labeled claims in commercial products. The proposed method is economical, convenient, and suitable for the quantification of lactulose in pharmaceutical preparations. The text was submitted by the authors in English.     

Preparation and Characterization of PbS Nanoparticles via Cyclic Microwave Radiation Using Precursor of Lead (II) Oxalate

PbS nanoparticles have been successfully synthesized through a simple, rapid microwave route using lead (II) oxalate as precursor, [Pb(O₄C₂)]. In this study, four different sulfur sources were applied that including sodium thiosulfate (Na₂S₂O₃), thioacetamide (NH₂CSCH₃), thioglycolic acid (HSCH₂CO₂H), and l-cysteine (HO₂CCH(NH₂)CH₂SH). The effects of sulfur sources on morphology and size of products in two different solvents, ethylene glycol (EG) and poly EG (PEG 400), were investigated. The products were analyzed by X-ray diffraction analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray energy dispersive spectroscopy. Photoluminescence was used to study the optical properties of PbS nanoparticles.