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⁺.     

A gamma-ray scattering technique for estimation of density and moisture content of wood

A densitometer system, operating in a non-destructive and non-invasive way, is presented to investigate the density and moisture variation in wood samples of Pinus roxburghii (known as chir pine). The inherent ability of Compton scattering can ascertain quantitative information of electron density of the target material. A well collimated beam of 662?keV gamma rays from ¹³⁷Cs radioactive source has been used to extract the information of density from interior of sample by recording scattered spectra with NaI(Tl) scintillation detector. An inverse matrix approach for unfolding of observed pulse-height distribution to a true photon spectrum is used, by choosing bin mesh (E^1/2) of 0.025 (MeV)^1/2, for the measurements of scattered spectra. The regression lines, obtained from data of scattered spectra, provide the density and moisture content of selected wood sample. The adjusted R² value 0.984 for fitted curve, justifies the linear dependence of scattered intensity upon wood density. Also, Compton scatter measurements results that the technique is less sensitive beyond wood thickness of ～110?mm due to overlying scatter components in the measured spectrum.     

Pharmacokinetic Characterization of (Poly)phenolic Metabolites in Human Plasma and Urine after Acute and Short-Term Daily Consumption of Mango Pulp

Pharmacokinetic (PK) evaluation of polyphenolic metabolites over 24 h was conducted in human subjects (n = 13, BMI = 22.7 ± 0.4 kg/m²) after acute mango pulp (MP), vitamin C (VC) or MP + VC test beverage intake and after 14 days of MP beverage intake. Plasma and urine samples were collected at different time intervals and analyzed using targeted and non-targeted mass spectrometry. The maximum concentrations (C_max) of gallotannin metabolites were significantly increased (p < 0.05) after acute MP beverage intake compared to VC beverage alone. MP + VC beverage non-significantly enhanced the C_max of gallic acid metabolites compared to MP beverage alone. Pyrogallol (microbial-derived metabolite) derivatives increased (3.6%) after the 14 days of MP beverage intake compared to 24 h acute MP beverage intake (p < 0.05). These results indicate extensive absorption and breakdown of gallotannins to galloyl and other (poly)phenolic metabolites after MP consumption, suggesting modulation and/or acclimation of gut microbiota to daily MP intake.     

Complexes of Metal Ions with Phosphorus or Arsenic containing Ligands. Part. XIII. Reactions of o-carboxyphenylmonotertiaryarsines and their oxides with beryllium(II) oxide acetate

Ligands, o-carboxyphenyldiphenylarsine, o-carboxyphenyldi(p-tolyl)arsine, o-carboxyphenyldiphenylarsine oxide and o-carboxyphenyldi(p-tolyl)arsine oxide react with beryllium(II) oxide acetate to form complexes of the general formula, [Be₄ · O · (CH₃COO)₃(L)₃] where LH is any of the aforementioned ligands. These have been found to be nonelectrolytes in nitrobenzene. Infrared spectral data suggest that arsenic(III or V) is not coordinated to the metal, while both the oxygens of acetate as well as carboxylate group are taking part in coordination, leaving the fundamental structure of beryllium oxide acetate intact.     

Complexation reaction of metal ions with peptide systems. Part II. Potentiometric studies of the complexes of glycyl-DL-valine with Gd, Dy, Er and Yb

The stable complexes of amino acids with rare earths have found importance in the separation of these metals¹. The complexation reactions of a number of dipeptides with copper and nickel have been reported in the literature^{2 – 9}; but little work appears to have been done with rare earth metals. This paper is a continuation of our earlier communication¹⁰, and deals with the study of complexes of Gd³⁺, Dy³⁺, Er ³⁺ and Yb³⁺ with Glycyl-DL-valine. The Calvin—Bjerrum^{11, 12} pH titration technique, as modified by Irving and Rossotti¹³, has been employed.     

Experimental realization of an on-chip all-optical analogue to electromagnetically induced transparency

We provide the first experimental observation of structure tuning of the electromagnetically induced transparency-like spectrum in integrated on-chip optical resonator systems. The system consists of coupled silicon ring resonators with 10 microm diameter on silicon, where the coherent interference between the two coupled resonators is tuned. We measured a transparency-resonance mode with a quality factor of 11,800.     

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.