QQˉQ\bar Q (Q∈{b,c}Q\in \{b, c\}) spectroscopy using Cornell potential

The mass spectra and decay properties of heavy quarkonia are computed in nonrelativistic quark-antiquark Cornell potential model. We have employed the numerical solution of Schr\"odinger equation to obtain their mass spectra using only four parameters namely quark mass ($m_c$, $m_b$) and confinement strength ($A_{c\bar c}$, $A_{b\bar b}$). The spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction are computed perturbatively to determine the mass spectra of excited $S$, $P$, $D$ and $F$ states. Digamma, digluon and dilepton decays of these mesons are computed using the model parameters and numerical wave functions. The predicted spectroscopy and decay properties for quarkonia are found to be consistent with available experimental observations and results from other theoretical models. We also compute mass spectra and life time of the $B_c$ meson without additional parameters. The computed electromagnetic transition widths of heavy quarkonia and $B_c$ mesons are in tune with available experimental data and other theoretical approaches

Superconductivity in 2-2-3 system Y2Ba2Cu2O(8+delta)

Researchers synthesized a new high T(sub c) 2-2-3 superconductor Y2Ba2Cu3O(8+delta) by a special preparation technique and characterized it by ac-susceptibility measurements. Diamagnetism and Meissner effect sets in at low fields and superconducting transition onsets at 90 K. The systematic investigation of the real and imaginary components of ac-susceptibility as a function of temperature and applied ac magnetic field reveals that the magnetic behavior is that of a granular type superconductor

COMPARATIVE PHARMACOGNOSTICAL AND PHYTOCHEMICAL STUDY OF VARIOUS SPECIES OF THE CONTROVERSIAL DRUG ‘PUNARNAVA'

Objective: Punarnava is a controversial drug i.e. its true botanical identity has not been ascertained, and several different species are used as Punarnava. It is a part of many medicinally important traditional formulations. Ayurvedic Pharmacopoeia of India describes three different species–Roots of Boerhaavia diffusa, Trianthema portulacastrum and Boerhaavia verticillata. The present work deals with the microscopic, macroscopic and phytochemical comparison of the roots of these species of Punarnava, so as to differentiate them and establish their quality parameters.Methods: Roots of these three species were collected, and their comparative morphological, microscopical (transverse section, powder study) and the phytochemical (screening, tannin estimation) study was performed.Results: Roots of Boerhaavia diffusa showed morphological characteristics which clearly distinguished it from the other species. They showed the presence of well developed and stratified cork, abnormal vascular bundles which were discontinuous, and a central cavity, presumably formed due to the disintegration of tissues. Boerhaavia verticillata showed the presence of xylem bundles arranged in the form of a ‘X'-shaped cross in the central region. Thick-walled cork cells and pitted xylem vessels were present only in Boerhaavia diffusa root powder, whereas bundles of fibrovascular tissue were present only in the powder of Boerhaavia verticillata. Tannin content was found to be highest in Boerhaavia diffusa roots.Conclusion: The present investigation will help herbal industries and traditional medicinal practitioners to detect adulteration of the medicinally important immunomodulator Boerhaavia diffusa by Trianthema portulacastrum and Boerhaavia verticillata, which are considered to have no immunomodulatory activity.Â

Diesel exhaust and asthma: hypotheses and molecular mechanisms of action.

Several components of air pollution have been linked to asthma. In addition to the well-studied critera air pollutants, such as nitrogen dioxide, sulfur dioxide, and ozone, diesel exhaust and diesel exhaust particles (DEPs) also appear to play a role in respiratory and allergic diseases. Diesel exhaust is composed of vapors, gases, and fine particles emitted by diesel-fueled compression-ignition engines. DEPs can act as nonspecific airway irritants at relatively high levels. At lower levels, DEPs promote release of specific cytokines, chemokines, immunoglobulins, and oxidants in the upper and lower airway. Release of these mediators of the allergic and inflammatory response initiates a cascade that can culminate in airway inflammation, mucus secretion, serum leakage into the airways, and bronchial smooth muscle contraction. DEPs also may promote expression of the T(subscript)H(/subscript)2 immunologic response phenotype that has been associated with asthma and allergic disease. DEPs appear to have greater immunologic effects in the presence of environmental allergens than they do alone. This immunologic evidence may help explain the epidemiologic studies indicating that children living along major trucking thoroughfares are at increased risk for asthmatic and allergic symptoms and are more likely to have objective evidence of respiratory dysfunction

PDF model based on Langevin equation for polydispersed two-phase flows applied to a bluff-body gas-solid flow,

The aim of the paper is to discuss the main characteristics of a complete theoretical and numerical model for turbulent polydispersed two-phase flows, pointing out some specific issues. The theoretical details of the model have already been presented [Minier and Peirano, Physics Reports, Vol. 352/1-3, 2001 ]. Consequently, the present work is mainly focused on complementary aspects, that are often overlooked and that require particular attention. In particular, the following points are analysed : the necessity to add an extra term in the equation for the velocity of the fluid seen in the case of twoway coupling, the theoretical and numerical evaluations of particle averages and the fulfilment of the particle mass-continuity constraint. The theoretical model is developed within the PDF formalism. The important-physical choice of the state vector variables is first discussed and the model is then expressed as a stochastic differential equation (SDE) written in continuous time (Langevin equations) for the velocity of the fluid seen. The interests and limitations of Langevin equations, compared to the single-phase case, are reviewed. From the numerical point of view, the model corresponds to an hybrid Eulerian/Lagrangian approach where the fluid and particle phases are simulated by different methods. Important aspects of the Monte Carlo particle/mesh numerical method are emphasised. Finally, the complete model is validated and its performance is assessed by simulating a bluff-body case with an important recirculation zone and in which two-way coupling is noticeable.Comment: 23 pages, 10 figure