Search for CP violation in the decay B0-->D*+/-D-/+

We report a search for CP-violating asymmetry in B0-->D(*+/-)D-/+ decays. The analysis employs two methods of B0 reconstruction: full and partial. In the full reconstruction method all daughter particles of the B0 are required to be detected; the partial reconstruction technique requires a fully reconstructed D- and only a slow pion from the D(*+)-->D0pi(+)(slow) decay. From a fit to the distribution of the time interval corresponding to the distance between two B meson decay points we calculate the CP-violating parameters and find the significance of nonzero CP asymmetry to be 2.7 standard deviations.     

Observation of radiative B-->phi K gamma decays

The radiative decay B-->phi K gamma is observed for the first time. The branching fraction for the charged B--->phi K- gamma decay mode is measured to be B(B--->phi K- gamma)=(3.4+/-0.9+/-0.4)x10(-6). The photon energy distribution for the B--->phi K- gamma decay is presented. The signal for the neutral B(0)-->phi K(0)gamma decay mode is not statistically significant and an upper limit, B(B(0)-->phi K(0)gamma)<8.3x10(-6) at 90% C.L., is set. The analysis is based on a data set of 90 fb(-1) collected by the Belle experiment at the e(+)e(-) asymmetric collider KEKB.     

Quantum theory of stimulated raman scattering in an inhomogeneously broadened three-level gaseous system

A quantum-statistical treatment of stimulated Raman scattering in a gaseous system is presented using a density-matrix formalism. The molecular (atomic) system is described by three energy levels. Both atomic system and the radiation fields are quantized. The effects of atomic motion and detuning are incorporated in the analysis. Higher order nonlinearities and loss terms are included to render the problem more realistic. The equations of motion describing the photonstatistics of pump and Stokes fields are obtained. The equation, without detailed balance, is solved in the steady-state by a slowly varying function technique in the case of two variables. The steady state characteristics of the Stokes field are studied. The coherence properties, occurrence of antibunching phenomena are studied for different initial distributions.     

"Click" synthesis and properties of carborane-appended large dendrimers

Large dendrimers, noted G(n)-3(n+2)cage, containing 3(n+2) o-carborane cluster cages MeC(2)B(10)H(10) at their peripheries (n = number of generation noted G(n)) have been synthesized by Huisgen-type azide alkyne Cu(I)-catalyzed dipolar "click" cycloaddition reactions (CuAAC) between an o-carborane monomeric cluster containing an ethynyl group and arene-centered azido-terminated dendrimers G(n)-3(n+2)N(3) of generations 0, 1, and 2. Attempts to synthesize higher-generation dendrimers of this family yielded insoluble materials. The carborane dendrimers G(0)-9cage, G(1)-27cage, and G(2)-81cage have been characterized by (1)H, (13)C, (11)B NMR, elemental analysis, matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectroscopy, and size exclusion chromatography (SEC) showing low polydispersities, dynamic light scattering (DLS) showing hydrodynamic diameters of 5.7 nm for the G(1)-27cage and the 12.9 nm for the G(2)-81cage. These dendrimers are extremely robust thermally, with 10% mass loss temperatures of 411 °C for the G(0)-9cage, 371 °C for the G(1)-27cage, and 392 °C for the G(2)-81cage. They all showed a strong absorption in the UV region peaking at 258 nm, whereas emission spectra of low intensities were observed between 280 and 480 nm.     

Comparative Pharmacokinetics Profile of Vasa Swaras with Vasicine and Vasicinone

An RP-LC method was developed and validated for comparing the pharmacokinetics profile of Vasa Swaras (leaf juice of Adhatoda vasica Nees., Fam. Acanthaceae) with that of the pure vasicine and vasicinone (chief marker compounds of A. vasica) upon oral administration of Vasa Swaras in rats, and also in different animal groups. Significant difference with p < 0.05 was found in the oral bioavailability of vasicine and vasicinone when administered as Vasa Swaras and as single vasicine and/or vasicinone. Vasicine and vasicinone were found to be more bioavailable from Vasa Swaras than pure vasicine and/or vasicinone.     

Proton radioactivity with a Yukawa effective interaction

The half-lives of proton radioactivity of proton emitters are investigated theoretically. Proton-nucleus interaction potentials are obtained by folding the densities of the daughter nuclei with a finite-range effective nucleon-nucleon interaction having Yukawa form. The Wood-Saxon density distributions for the nuclei used in calculating the nuclear as well as the Coulomb interaction potentials are predictions of the interaction. The quantum mechanical tunneling probability is calculated within the WKB framework. These calculations provide reasonable estimates for the observed proton radioactivity lifetimes. The effects of neutron-proton effective mass splitting in neutron-rich asymmetric matter as well as the nuclear matter incompressibility on the decay probability are investigated.     

The magnetization of PrFeAsO0.60F0.12 superconductor

The magnetization of the PrFeAsO_0.60F_0.12 polycrystalline sample has been measured as functions of temperature and magnetic field (H). The observed total magnetization is the sum of a superconducting irreversible magnetization and a paramagnetic magnetization. Analysis of dc susceptibility χ(T) in the normal state shows that the paramagnetic component of magnetization comes from the Pr³⁺ magnetic moments. The intragrain critical current density (J_L) derived from the magnetization data is large. The J_L(H) curve displays a second peak which shifts towards the high-field region with decreasing temperature. In the low-field region, a plateau up to a field H^* followed by a power law H^?5/8 behavior of J_L(H) is the characteristic of the strong pinning. A vortex phase diagram for the present superconductor has been obtained from the magnetization and resistivity data.     

Secondary ion mass spectrometry and X-ray photoelectron spectroscopy studies on TiO2 and nitrogen doped TiO2 thin films

Anatase phase TiO₂ and nitrogen (N) doped TiO₂ thin films were synthesized by an ultrasonic spray pyrolysis technique on c-Si (100) substrates in the temperature range 300-550 °C. The former used a precursor solution of titanium oxy acetylacetonate in methanol whereas the later used a titanium oxy acetylacetonate hexamine mixture in methanol. Homogeneity across the film’s thickness and the nature of the film-substrate interface were studied by dynamic depth profiling acquired using secondary ion mass spectrometry SIMS. The stoichiometry and bonding state of various species present in the films were studied using X-ray photoelectron spectroscopy (XPS). N-doping was confirmed by both SIMS and XPS. XPS studies revealed that the nitrogen content of the films synthesized at 300 °C (3.2%) is high compared to that of films made at 350 °C (1.3%).     

Sample Treatment Approaches for Trace Level Determination of Cesium in Hepatitis B Vaccine by Suppressed Ion Chromatography

The hepatitis B surface antigen manufactured by recombinant DNA technology is extracted from the culture media by density gradient centrifugation using cesium salts. Cesium is considered to be toxic, because it affects active ion transport by blocking potassium channels. The residual trace levels of cesium in hepatitis B vaccine samples are determined by suppressed ion chromatography. Hepatitis B vaccines contain various buffer salts, aluminum-containing adjuvants, proteins and traces of iron. The polyvalent cations (Al³⁺, Fe³⁺) and proteins degrade the chromatographic performance in terms of decreased retention time and poor reproducibility. Different sample preparation approaches were evaluated with the aim of eliminating these foulants: (1) filtration, (2) digestion and (3) digestion-protein precipitation. Quantitative elimination of these foulants was achieved in the digestion-protein precipitation sample clean-up approach. Cesium was separated on the IonPac CS17 column with suppressed conductivity detection. The results of the ion chromatography (IC) method were compared with ICP-MS analysis. The precision of determination was better than 6.5% (relative standard deviation) with a method detection limit of 45 ng mL⁻¹. The expanded uncertainty in the measurement at 95% confidence level (coverage factor 2) is better than 16.3%.