New Sm (III) and Nd (III) complexes: Synthesis,structural characterization and fluorescent sensing of nitro‐aromatic compounds

In this work, four new Nd (III) and Sm (III) complexes of two pentadendate ligands (L¹ and L²) were prepared and their molecular structures were determined by single crystal X‐ray diffraction studies. X‐ray analysis showed that the Nd (III) and Sm (III) complexes of L¹ sits on a twofold crystallographic axis while the complexes of L² does not show crystallographically imposed symmetry. Absorption and photoluminescence properties of the complexes were studied both in the solid state and DMF solutions. The fluorescence sensing of nitro‐aromatic compounds [nitrobenzene (NB), 4‐nitrophenol (NP), 2,4‐dinitrophenol (DNP) and 2,4,6‐trinitrophenol (TNP)] were studied by photoluminescence spectroscopy. All four complexes showed better sensitivity towards nitrophenol (NP) with low LOD values.     

High-rate LDPC codes from partially balanced incomplete block designs

Journal of Algebraic Combinatorics - This paper presents a combinatorial construction of low-density parity-check (LDPC) codes from partially balanced incomplete block designs. Since...     

Tridentate benzimidazole ligand and its metal complexes: Synthesis,characterization, photo physical and sensor properties

A tridentate bisbenzimidazole-pyridine ligand (L-C⁵) with two pentyl side-units and its metal complexes with Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺ metal ions were synthesized and characterized. The structures of the ligand (L-C⁵) and its five coordinate [Mn(L-C⁵)Cl₂] were elucidated by single crystal X-ray diffraction studies. The absorption and photoluminescence properties of the compounds were studied in solution media. The ligand is highly fluorescent, and binding of the metal ions to the ligand has caused significant changes in the emission band (shift or quenching). Moreover, the effect of aggregation on UV–Vis. absorption and emission properties was examined in MeOH-water mixtures. The ligand was found to show aggregation-induced quenching in the MeOH-water mixture. The ligand was also screened for its colorimetric and fluorometric sensing ability of several metal ions [Na⁺, K⁺, Mg²⁺, Al³⁺, Ca²⁺, Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Hg²⁺, Pb²⁺]. The ligand showed selective sensing ability towards Zn²⁺, and the limit of detection was calculated as 3.09 × 10⁻⁷ m . The ligand also showed a distinguishable color change in the presence of Fe²⁺ under daylight.     

Investigation of neutron sensitivity of un-doped and Dy-doped CaB<Subscript>4</Subscript>O<Subscript>7</Subscript> for thermoluminescence applications

In this study, thermoluminescence characteristics of un-doped and Dy-doped calcium tetraborate (CaB₄O₇) compounds are reported. The polycrystalline powder samples of un-doped and Dy-doped CaB₄O₇ were prepared by a solid-state reaction at high-temperature method. The identification and characteristics of the obtained compounds were determined by X-ray diffraction, Fourier transform infrared analysis, differential thermal analysis, thermogravimetric analysis, and scanning electron microscopy. The glow curves were obtained using a thermoluminescent reader. Neutron sensitivity, dose–response, and heating rate of CaB₄O₇ compounds were determined by using a bare ²⁵²Cf mixed neutron?+?gamma (n?+?γ) source, and dose response results are compared to those of Harshaw TLD-600 and TLD-700 neutron dosimeters (⁶LiF:Mg,Ti and ⁷LiF:Mg,Ti). The sensitivity of CaB₄O₇:Dy (0.5%) sample is approximately 4.35 and 3.36 times higher than that of TLD-600 and TLD-700, respectively.     

Orthogonal Trades and the Intersection Problem for Orthogonal Arrays

This work provides an orthogonal trade for all possible volumes \(N \in \mathbb {Z}^+ \setminus \{1,2,3,4,5,7\}\) for block size 4. All orthogonal trades of volume \(N\leqslant 15\) are classified up to isomorphism for this block size. The intersection problem for orthogonal arrays with block size 4 is solved for all but finitely many possible exceptions.     

Determination and speciation of selenium in water samples collected from Muğla (Turkey) province by hydride generation atomic absorption spectrometry

In this work, determination of selenium in various water samples was done by using hydride generation atomic absorption spectrometry. The most appropriate values of HCl concentration, NaBH₄ concentration, NaOH concentration, flow rate of argon and flow rate of waste solution were determined. The optimum concentration of the HCl, NaBH₄ and NaOH solutions were found to be 7.0 mol L^?1, 1.0% and 0.75%, respectively. The optimum flow rate of Ar gas and waste solution were also found to be 100.9 mL min^?1 and 4.0 mL min^?1, respectively. Values of LOD and LOQ were calculated separately for total Se and Se(IV). LOD and LOQ values were calculated 0.56 μg L^?1, 1.87 μg L^?1 for total Se and 0.72 μg L^?1, 2.40 μg L^?1 for Se(IV), respectively. The precision was evaluated by relative standard deviation (RSD%) was found to be 3.5% for total Se and 3.1% for Se(IV) (n = 11). A standard reference material (NIST 1643e) was used in order to check the accuracy of the proposed method. There was a good agreement between certified and found values for standard reference material. The method was applied to the analysis of total Se and Se(IV) concentrations in tap water samples collected from the various regions of Mu?la. Proposed method showed spike recovery ranges from 92% to 116% in water samples.     

Half-sandwich ruthenium(II) complexes containing 4-substituted aniline derivatives: structural characterizations and catalytic properties in transfer hydrogenation of ketones

Transition Metal Chemistry - Four half-sandwich Ru(II) complexes (1)–(4) with the general formulae [Ru(η6-p-cymene)(L)Cl2] were synthesized by the reaction of one equivalent of the...     

A Novel Flow-injection Rhodium Nanoparticles Modified Phosphate Biosensor and its Operation in Artificial Urine

A biosensor for phosphate determination with the flow-injection system was developed using rhodium nanoparticles modified Poly(pyrrole-co-[1-(2-aminophenyl) pyrrole])/pyruvate oxidase. The biosensor showed a very wide linearity up to 70 mM phosphate concentration compared to previously reports, response time of 4 s., operational stability with a relative standard deviation of 0.009 % and accuracy of 99.4 %±0.949 at a flow rate of 2.0 Ml min.⁻¹ at exactly −0.68 V. Detection limit were calculated to be 21±0.001 μM by preserving 81.1 % of its initial response at the end of 16^th days. Artificial urine was analyzed without dilution to investigate biosensor performance.     

Efficiency of the Turkish Stock Exchange with respect to monetary variables: A cointegration analysis

In this study, we test the semistrong form of the efficient market hypothesis in Turkey by using the recently developed techniques in time series econometrics, namely unit roots and cointegration. The long run relationship between stock prices and inflation is investigated by assuming the possible existence of a proxy effect. Conclusions are made as to the efficiency of the Turkish Stock Exchange and its possible implications for investors. To our knowledge, this is among the pioneering studies conducted in an emerging market that uses an updated econometric methodology to allow for an analysis of long run steady state properties together with short run dynamics.