Study of exclusive charmless semileptonic B decays and |Vub|

We study semileptonic B decay to the exclusive charmless states pi, rho/omega, eta, and eta;{'} using the 16 fb(-1) CLEO Upsilon(4S) data sample. We find B(B0-->pi-l+nu)=(1.37+/-0.15stat+/-0.11sys)x10(-4) and B(B0-->rho-l+nu)=(2.93+/-0.37stat+/-0.37sys)x10(-4) and find evidence for B+-->eta'l+nu, with B(B+-->eta'l+nu)=(2.66+/-0.80stat+/-0.56sys)x10(-4). From our B-->pilnu rate for q2>16 GeV2 and lattice QCD, we find |Vub|=(3.6+/0.4stat+/0.2syst-0.4thy+0.6)x10(-3) [corrected]     

A note on the unsteady flow of a fractional Maxwell fluid through a circular cylinder

In this note the velocity field and the adequate shear stress corresponding to the unsteady flow of a fractional Maxwell fluid due to a constantly accelerating circular cylinder have been determined by means of the Laplace and finite Hankel transforms.The obtained solutions satisfy all imposed initial and boundary conditions.They can easily be reduced to give similar solutions for ordinary Maxwell and Newtonian fluids.Finally,the influence of pertinent parameters on the fluid motion,as well as a comparison between models,is underlined by graphical illustrations.     

Kinetics and mechanism of chromic acid oxidation of oxalic acid in absence and presence of different acid media. A kinetic study

Kinetics and mechanism of the reaction of Cr(VI) with oxalic acid have been studied in presence and absence of H₂SO₄, HClO₄, and CH₃COOH by monitoring the formation of Cr(III)-oxalic acid complex at 560 nm. The effect of total [oxalic acid], [Cr(VI)], [H₂SO₄], [HClO₄], and [CH₃COOH] on the reaction rate was determined at 30°C. Formation of carbon dioxide was also confirmed. The oxidation rate increases with [oxalic acid] and [CH₃COOH] while it decreases with [H₂SO₄], [HClO₄], and pH. The rate law governing the oxidation of oxalic acid over a wide range of conditions is rate=k₁ K_es1 [oxalic acid]_T [Cr(VI)]_T 1+K_es1 [oxalic acid]_T, where only undissociated oxalic acid is kinetically active. Kinetic evidence for the formation of a Cr(VI)(SINGLEBOND)oxalic acid 1:1 complex has been obtained and the equilibrium constant for their formation has been determined. The 1:1 complex exists most likely in an open chain form. The rate-limiting step of the oxidation reaction involves the breaking of the C(SINGLEBOND)C bond in the 1:2 complex. Oxidizing ability of Cr(VI) species have been discussed. Mechanism with the associated reaction kinetics is assigned. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 335–340, 1998     

Measuring diffusion coefficients of gaseous propane in heavy oil at elevated temperatures

Journal of Thermal Analysis and Calorimetry - Molecular diffusion is an important phenomenon for solvent transport during vapor extraction and hot solvent injection into heavy oil reservoirs....     

Affordable and rapid HPTLC method for the simultaneous analysis of artemisinin and its metabolite artemisinic acid in Artemisia annua L.

Artemisinin (AN) and artemisinic acid (AA), valuable phyto‐pharmaceutical molecules, are well known anti‐malarials, but their activities against diseases like cancer, schistosomiasis, HIV, hepatitis‐B and leishmaniasis are also being reported. For the simultaneous estimation of AN and AA in the callus and leaf extracts of A. annua L. plants, we embarked upon a simple, rapid, selective, reliable and fairly economical high performance thin layer chromatography (HPTLC) method. Experimental conditions such as band size, chamber saturation time, migration of solvent front and slit width were critically studied and the optimum conditions were selected. The separations were achieved using toluene–ethyl acetate, 9:1 (v/v) as mobile phase on pre‐coated silica gel plates, G 60F₂₅₄. Good resolution was achieved with R_f values of 0.35 ± 0.02 and 0.26 ± 0.02 at 536 nm for AN and 626 nm for AA, respectively, in absorption–reflectance mode. The method displayed a linear relationship with r² value 0.992 and 0.994 for AN and AA, respectively, in the concentration range of 300–1500 ng for AN and 200–1000 ng for AA. The method was validated for specificity by obtaining in‐situ UV overlay spectra and sensitivity by estimating limit of detection (30 ng for AN and 15 ng for AA) and limit of quantitation (80 ng for AN and 45 ng for AA) values. The accuracy was checked by the recovery studies conducted at three different levels with the known concentrations and the average percentage recovery was 101.99% for AN and 103.84% for AA. The precision was analyzed by interday and intraday precision and was 1.09 and 1.00% RSD for AN and 1.22 and 6.05% RSD for AA. The analysis of statistical data substantiates that this HPTLC method can be used for the simultaneous estimation of AN and AA in biological samples. Copyright © 2015 John Wiley & Sons, Ltd.     

Charged lepton production from iron induced by atmospheric neutrinos

The charged current lepton production induced by neutrinos in ⁵⁶Fe nuclei has been studied. The calculations have been done for the quasielastic as well as the inelastic reactions assuming Δ-dominance and take into account the effect of Pauli blocking, Fermi motion and the renormalization of weak transition strengths in the nuclear medium. The quasielastic production cross-sections for lepton production are found to be strongly reduced due to nuclear effects, while there is about 10% reduction in the inelastic cross-sections in the absence of the final-state interactions of the pions. The numerical results for the momentum and angular distributions of the leptons averaged over the various atmospheric-neutrino spectra at the Soudan and Gran Sasso sites have been presented. The effect of nuclear-model dependence and the atmospheric-flux dependence on the relative yield of μ to e has been studied and discussed.     

Synthesis,characterization and antimicrobial screening of a novel organylborate ligand,potassium hydro(phthalyl)(salicylyl)borate and its Co(II), Ni(II), and Cu(II) complexes

A new organylborate ligand, potassium hydro (phthalyl) (salicylyl) borate and its Co(II), Ni(II), and Cu(II) complexes were synthesized. The compounds were characterized by elemental analysis, FTIR, ¹H NMR, ESI MS, UV–Vis techniques, molar conductivity and magnetic data measurements. The spectroscopic data support a distorted square planar geometry around the Cu(II) ion, while the Co(II) and Ni(II) ions acquire a distorted octahedral geometry. These synthesised compounds were also tested for their in vitro antimicrobial activities against some bacterial and fungal strains to assess their inhibiting potential and the activities shown by these complexes were compared with standard drugs. Results showed that there is a marked increase in the antibacterial and antifungal activities of the cobalt(II) complex than the free ligand and other complexes when treated against the same microorganism at the same concentration.     

Conformational equilibrium study of calix[4]tetrolarenes using Density Functional Theory (DFT) and Molecular Dynamics simulations

The present work deals with the theoretical study of conformational equilibrium of calix[4]tetrolarenes (1,2,3 trimethoxy substituted calix[4]arene) in gaseous and solvation phases. A total of 64 calculations (four conformations at eight level of theories) were performed using Density Functional Theory (DFT) functionals viz. wB97XD, B97D, B3LYP, CAM-B3LYP with diffused (6–31 + G(d)) and non-diffused basis sets (6-31G(d)). It has been found that the conformational profile of calix[4]tetrolarene changes from cone to 1,3-Alternate upon incorporating – OMe group. The B97D and wB97XD functionals gave the most accurate result having rmsd value ~0.73Å followed by B3LYP and CAM-B3LYP > 0.78Å. Furthermore, NBO calculations demonstrated that reduction in charges at lower rim oxygens reduces the chances of hydrogen bonding. Moreover, global reactivity parameters and molecular dynamics also complement the observed trend. Owing to the methoxy substitutions, anion binding study of these new molecules indicates towards the promising capability to bind Cl^? and F^? ions.     

Equilibrium,kinetic and thermodynamic biosorption studies of Hg(II) on red algal biomass of Porphyridium cruentum

Among a variety of microbial materials employed for biosorption, algae have added advantages of non-toxic and autotrophic nature. In this study, biosorption of Hg(II) was studied with red algal biomass of Porphyridium cruentum. The parameters affecting biosorption such as dosage of biosorbent, pH, contact time, initial metal concentration, temperature and effect of foreign metal cations in binary system were evaluated. Kinetic data were described with the help of pseudo-first-order and pseudo-second-order kinetic models. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models were applied to adsorption equilibrium data. According to the results, the maximum removal capacity (q_max) was 2.62?mg/g observed at pH 7 with 0.25?g/L of biosorbent dosage for Hg(II) solution containing 10?mg/L of metal ions. The Langmuir isotherm model fits best to the adsorption data while the kinetic data followed the pseudo-second-order model. Thermodynamics studies showed that the biosorption process of Hg(II) on P. cruentum was exothermic in nature.