Ultrasonic Determination of the Jahn–Teller Effect Parameters in Impurity-Containing Crystals

Journal of Experimental and Theoretical Physics - A method is developed to determine the symmetry properties of strains and the type of Jahn–Teller effect in crystals with impurity ions in a...     

Structural,Morphological and Optical Properties of Well-Ordered CdO Nanostructures Synthesized by Easy-Economical Chemical Bath Deposition Technique

In this Study, Cadmium Oxide (CdO) nanostructures were synthesized by using Chemical Bath Deposition Technique. The synthesized process was carried out at room temperature. The structural and optical properties of nanostructures was characterized by XRD, SEM and UV-Vis techniques. As a result, the CdO nanostructures are oriented along (111) plane of cubic crystal structure. The morphology of CdO nanostructures showed interconnected prism-like and cauliflower-type cluster nanostructure. The UV results of this structures with high absorbtion coefficient are observed to be in accordance with the CdO nanoparticles.     

Highly active sites of NiVB nanoparticles dispersed onto graphene nanosheets towards efficient and pH-universal overall water splitting

Production of hydrogen (H2) and oxygen (O2) through electrocatalytic water splitting is one of the sustainable,green and pivotal ways to accomplish the ever-inc...     

Effect of Al2O3 content and milling time on microstructure and mechanical properties of aluminum metal matrix composites

Experimental Techniques - In this study, aluminum metal matrix composites (Al-MMCs) reinforced with aluminum oxide (Al2O3) (5, 10, 15 wt%) were produced using the powder metallurgy (PM) process....     

Synthesis and spectral properties of some N-(2-benzimidazoyl)-α-aminoesters and their N-oxides

A series of new N-(2-benzimidazol)(S)-α-aminoesters and the respective N-oxides have been prepared, and their spectral data discussed. The CD spectra of the aliphatic and aromatic amino ester derivatives of either series show sign reversal for the observed Cotton effect (CE) band. This chiroptical behaviour was rationalized as due to differences in conformational isomerism.     

New diterpene isopimara-7,15-dien-19-oic acid and its prolyl endopeptidase inhibitory activity

The ethanolic extract of the bulbs of Fritillaria imperialis was subjected to fractionation by solvent-solvent extraction. The nonpolar fraction showed inhibitory activity against prolyl endopeptidase (PEP) (EC.3.4.21.26), a large intracellular enzyme that preferentially hydrolyze proline-containing oligopeptidase at the carboxylic side of a prolyl residue. We have isolated a diterpenoid isopimara-7,15-dien-19-oic acid (1) from the nonpolar fraction of F. imperialis, and on methylation of compound 1, a methylester 2 was obtained which is a known compound previously isolated from Fritillaria thunbergii. The present article describes the isolation and structural elucidation of isopimara-7,15-dien-19-oic acid (1) by single-crystal X-ray diffraction techniques along with its prolyl endopeptidase inhibitory activity.     

Biotransformation of (+)-androst-4-ene-3,17-dione

Fermentation of (+)-androst-4-ene-3,17-dione (1) with Curvularia lunata for 10 days yielded five oxidative and reductive metabolites, androsta-1,4-diene-3,17-dione (2), 17beta-hydroxyandrosta-1,4-dien-3-one (3), 11alpha-hydroxyandrost-4-ene-3,17-dione (4), 11alpha,17beta-dihydroxyandrost-4-en-3-one (5) and 15alpha-hydroxyandrosta-1,4-dien-17-one (6). The structures of these metabolites were elucidated on the basis of spectroscopic techniques. These microbially transformed products were assayed against the clinically important enzymes, tyrosinase and prolyl endopeptidase.     

Separation and analysis of aluminium(III) by cation exchange ion chromatography

A method for the determination of aluminium(III) ions based on separation by cation exchange column chromatography and detection by conductivity detector has been developed. It is fast and reliable, and can be used for the separation and analysis of aluminium(III) ions from other metal ions like Mg(II), Mn(II), Zn(II), Co(II), Ca(II), Sr(II), rare earth elements like Lu(III), Tm(III), and Gd(III), which are eluted at different times and so do not interfere. Effect of p-phenylene diamine concentration present in the eluent, presence of other metal ions and effect of various anions present in the injection sample on the separation and analysis of aluminium(III) ions have also been studied.     

Examining prospective mathematics teachers' pedagogical content knowledge on fractions in terms of students' mistakes

The aim of the study is to examine prospective mathematics teachers’ pedagogical content knowledge in terms of knowledge of understanding students and knowledge of instructional strategies which are the subcomponents of pedagogical content knowledge. The participants of this research consist of 98 prospective teachers who are studying in two universities in Turkey. The participants were selected with the purposive sampling method which is one of the non-random sampling methods. Case study method, which is based on the qualitative research approach, was used. The answers given by secondary school students to fraction-related open-ended questions in the study of Soylu and Soylu were used as the data collection tool. The obtained data were analyzed via the content analysis technique. The analyses showed that the prospective mathematics teachers’ pedagogical content knowledge on fractions was not at an adequate level in identifying and correcting students’ errors. However, it was observed that the prospective teachers experienced more difficulty in the knowledge of instructional strategies compared to the knowledge of understanding students.     

Determination of antimony by using tungsten trap atomic absorption spectrometry

An electrically heated tungsten coil was used as a trap in the determination of antimony. The technique consists of three steps. Initially, SbH₃ is formed by hydride generation procedure; then the analyte species in vapor form are transported to W-coil trap heated at 370 °C. Following the preconcentration step, the trap is heated to 895 °C; analyte species are revolatilized and transported to the flame-heated quartz atom cell where atomization and the formation of signal take place. The experimental parameters were optimized both for trap and no-trap studies. The most important experimental parameters are concentrations of HCl and NaBH₄ solutions, H₂ and Ar gas flow rates, and collection and revolatilization temperatures of W-coil. Accuracy was tested using a certified reference material, waste water EU-L-1. Limit of detection for the system is 16 ng l^− 1 using a sample of 36 ml collected in 4.0 min. Enhancement factor in sensitivity was 17.