A thermodynamic study of complexation reaction of yttrium(III), lanthanum(III) and cerium(III) with tyrosine

The thermodynamic stability constants and thermodynamic parameters for complexation reaction of Y³⁺, La³⁺, and Ce³⁺ with tyrosine have been determined pH metrically. The study reveals the formation of 11 complexes for La³⁺ and Ce³⁺ whereas Y³⁺ yields both 11 and 12 complexes. The values of enthalpy changes (H ^o) indicate that unionised hydroxy group also participates in complexation.     

Benzo[b]thiophene derivatives. XXVI. 5-methoxy-6-chloro-3-β-acetamidoethylbenzo[b ]thiophene,a blocked analog of melatonin

A potential anti-ovulatory agent, 5-methoxy-6-chloro-3-β-acetamidoethylbenzo[b]thiophene, a sulfur analog of melatonin having the 6-position blocked to inhibit oxidative metabolism, has been synthesized from 3-hydroxy-4-chloroacetophenone.     

Molar extinction coefficients in aqueous solutions of some amino acids

Mass attenuation coefficients of amino acids viz. glycine (C₂H₅NO₂), l-Serine (C₃H₇NO₃), l-Theronine (C₄H₉NO₃), l-Proline (C₅H₉NO₂), l-Valine (C₅H₁₁NO₂) and l-Phenylalanine (C₉H₁₁NO₂) in aqueous solutions have been determined at 81, 356, 511, 662, 1173 and 1332 keV by the gamma-ray transmission method in a narrow beam good geometry setup. Precisely measured densities of these solutions were used for the determination of these coefficients which varied systematically with the corresponding changes in the concentrations (g/cm³) of the solutions. Molar extinction coefficients of amino acids were then obtained at these energies and were found to be in good agreement with the theoretical results. In addition, total interaction cross sections of amino acids in aqueous solutions were also calculated.     

A thermodynamic study of the complexation reaction of beryllium(II), magnesium(II) and calcium(II) with 3-hydroxy-2-naphtoic acid

The thermodynamic stability constants and thermodynamic parameters for the complexation reaction of Be²⁺, Mg²⁺ and Ca²⁺ with 3-hydroxy-2-naphthoic acid have been determined pH metrically in a 70% v/v dioxane-water medium in the presence of potassium nitrate. The study showed the formation 1:1 and 1:2 complexes of Be²⁺, Mg²⁺ and 1:1 complex of Ca²⁺ with 3-hydroxy-2-naphthoic acid. The order of overall stability is Be²⁺>Mg²⁺>Ca²⁺.     

Growth of carbon-doped base GaAs/AlGaAs HBT by gas-source MBE using TEG, TEA, TMG, AsH3, and Si2H6

High-performance carbon-doped-base GaAs/AlGaAs heterobipolar transistors (HBTs) were grown by gas-source MBE using only gaseous sources including dopant sources. The AlGaAs emitter layer was doped with Si from uncracked SI₂H₆ (n = 9 × 10¹⁷ cm^-3), and the base layer (92.5 nm) was doped with carbon from TMG (p = 4 × 10¹⁹ cm^-3). From SIMS analysis it was confirmed that a well-defined emitter-base junction with sharp carbon profile was obtained. The base-current ideality factor from the Gummel plot was 1.47, and the emitter-base junction ideality factor was 1.12. A high DC current gain of 53 was obtained at a current density of 4 × 10⁴ A/cm². The device characteristics of our carbon-doped HBTs were found to be stable under current stress.     

Zeolite-Hy : A Selective And Efficient Catalyst For The Alcoholyses Of Various Alcohols

An efficient and selective method for the conversion of various alcohols into their corresponding ethers in the presence of zeolite under sorvolytic condition is described. The reaction proceeds efficiently at ambient pressure in high yields.     

Detection of Staphylococcus aureus cell walls by enzyme-linked immunoassay using antibodies prepared from a semi-synthetic peptidoglycan precursor

The peptidoglycan layer of Staphylococcus aureus contains a (Gly)(5) cross-link which is not found in other bacteria, and which could be used to develop a specific immunoassay for detection of S. aureus in MRSA infections. A semi-synthetic route was used to prepare the S. aureus peptidoglycan precursor UDPMurNAc-L-Ala-γ-D-Glu-L-Lys(Gly)(5)-D-Ala-D-Ala, which was covalently attached to carrier protein bovine serum albumin via the UDP nucleotide. Serum raised using this antigen showed specificity for chemically immobilised peptidoglycan monomer containing (Gly)(5), using an ELISA immunoassay. ELISA assays using 0.1 or 1.0 μg samples of cell walls prepared from two MRSA strains and one penicillin-sensitive S. aureus strain, and from three other bacteria, showed the highest response against cell walls containing (Gly)(5), with a particularly high response against cell walls from one MRSA strain. Competition assays to investigate antibody selectivity demonstrated that the antibody response could be most effectively antagonised using ligands containing (Gly)(5). These data demonstrate that it is possible to generate antibodies with high affinity and selectivity for the (Gly)(5) containing monomer in S. aureus peptidoglycan, that could be used to develop an immunoassay for S. aureus.     

Adaptive fuzzy vendor managed inventory control for mitigating the Bullwhip effect in supply chains

This paper proposes an adaptive fuzzy control application to support a vendor managed inventory (VMI). The methodology applies fuzzy control to generate an adaptive smoothing constant in the forecast method, production and delivery plan to eliminate, for example, the rationing and gaming or the Houlihan effect and the order batching effect or the Burbidge effects and finally the Bullwhip effect. The results show that the adaptive fuzzy VMI control surpasses fuzzy VMI control and traditional VMI in terms of mitigating the Bullwhip effect and lower delivery overshoots and backorders. This paper also guides management in allocating inventory by coordinating suppliers and buyers to ensure minimum inventory levels across a supply chain. Adaptive fuzzy VMI control is the main contribution of this paper.     

In situ spatial mapping of Gouy phase slip for high-detail attosecond pump-probe measurements

Attosecond pump-probe experiments routinely utilize extreme ultraviolet (XUV) and IR fields, with relative phase being the variable parameter. However, the Gouy phase slip between the focused IR and XUV pulses inevitably leads to a certain amount of phase averaging and loss of accuracy. By using ion imaging, we establish a one-to-one mapping between the local phase slip and the spatial coordinates of the focal volume, thus performing in situ characterization of the Gouy phase of a complex beam and its role in ionization of He and Xe. We demonstrate that spatially discriminated ion imaging enhances the contrast of a phase-dependent XUV+IR ionization signal. We utilize our technique to unmask a weak ionization asymmetry, thus opening pathways for further high-precision attosecond studies.