Bimal Kumar Sarkar

First-principles calculations of the structural, phonon and thermal properties of ZnX (X = S, Se,Te) chalcogenides

Zinc chalcogenides, ZnX (X = S, Se and Te), are investigated with the full-potential linear-augmented plane wave method within the framework of the density functional theory for their structural, phonon and thermal properties. We consider the generalized gradient approximation for the purpose of exchange-correlation energy determination. Murnaghans equation of state is used for volume optimization by minimizing the total energy with respect to the unit cell volume. The elastic constants are calculated to examine the crystal structure stability, binding properties and bond character of zinc chalcogenides. By means of frozen-phonon method within the harmonic approximation, we work out phonon dispersion, lattice dynamics and thermal properties of ZnX compounds. The phonon frequencies in the first Brillouin zone, at the zone centre (Γ) and at the zone boundary (X or L) are estimated. The calculated lattice parameters and thermal parameters are in good agreement with other theoretical calculations as well as with the available experimental data.

Novel biomarker for prostate cancer diagnosis by MRS.

Magnetic resonance spectroscopy (MRS) is a prospective tool for characterization of the chemical composition of tissues. In vivo MRS can be used for metabolite profiling in the prostate tissue to discriminate non-invasively carcinomas and healthy prostate. In this article different prostate metabolites have been discussed and how to exploit the MRS technique for the estimation of metabolites in prostate tissue quantitatively is elucidated. Choline, citrate, creatine, myo-inositol metabolites can be considered as biomarker for localization of malignancy in the prostate and their ratio can be used for the determination of cancer tissue in the prostate gland.

Cohesive energy of zincblende (AIIIBV and AIIBVI) structured solids

In this paper we present an expression relating the cohesive energy (Ecoh in kcal/mol) of AIIIBV and AIIBVI semiconductors with the product of ionic charges (Z1Z2) and nearest-neighbour distance d (Å). The cohesive energy values of these solids exhibit a linear relationship when plotted on a log-log scale against the nearest-neighbour distance d (Å), but fall on different straight lines according to the ionic charge product of the solids. A good agreement has been found between the experimental and calculated values of the cohesive energy of AIIIBV and AIIBVI semiconductors.

Inherent properties of binary tetrahedral semiconductors

Abstract A new approach utilising the concept of ionic charge theory has been used to explain the inherent properties such as lattice thermal conductivity and bulk modulus of A III B V and A II B VI semiconductors. The lattice thermal conductivity ( K ) of these semiconductors exhibit a linear relationship when plotted on a log–log scale against the nearest neighbour distance d (A), but fall on two straight lines according to the product of the ionic charge of the compounds. On the basis of this result a simple lattice thermal conductivity–bulk modulus relationship is proposed and used to estimate the bulk modulus of these semiconductors. A fairly good agreement has been found between the experimental and calculated values of these parameters for zinc blende structured solids.

Dielectric constants of zinc-blende semiconductors

Empirical formulae are presented relating the dielectric constants of zinc-blende semiconductors with the average atomic number of the constituent atoms. The high-frequency e∞ and static e0 dielectric constants can be represented by an empirical linear relation that is a simple function of the average atomic number and the product of ionic charges (ZaZc). The calculated results are compared with the available experimental data and previous calculations based on phenomenological models.

The novel strategies for next-generation cancer treatment: miRNA combined with chemotherapeutic agents for the treatment of cancer

Medical practitioners are recommending combination therapy in cancer for its various advantages. Combination therapy increases the efficacy of treatment due to its synergistic effects in cancer treatment. In this post-genomic era, microRNAs (miRNAs) are receiving attention for their role in human disease and disease therapy. In this review, we discuss the combination of miRNAs and chemotherapeutic agents for cancer treatment. Moreover, we attempted to portray the role of miRNAs in cancer therapy; outline combination therapy, especially chemo-combination therapy, and discuss the basis for miRNA-based chemo-combination therapies and chemo-combination therapy with miRNA for cancer treatment.

Barrier–cluster–heating model and photoinduced phenomena in chalcogenide glasses

Barrier–cluster–heating model of disordered semiconductors was originated by synthesis of the barrier–cluster model (which was described in the previous works of authors) and of the local heating model (published short time ago). The synthesis of these two models brought synergic effect enabling deeper understanding of physical processes in amorphous semiconductors. The article gives a new view on the essence of some optical and photoinduced effects in chalcogenide glasses on the base of the barrier–cluster–heating model.

DNA pattern recognition using canonical correlation algorithm

We performed canonical correlation analysis as an unsupervised statistical tool to describe related views of the same semantic object for identifying patterns. A pattern recognition technique based on canonical correlation analysis (CCA) was proposed for finding required genetic code in the DNA sequence. Two related but different objects were considered: one was a particular pattern, and other was test DNA sequence. CCA found correlations between two observations of the same semantic pattern and test sequence. It is concluded that the relationship possesses maximum value in the position where the pattern exists. As a case study, the potential of CCA was demonstrated on the sequence found from HIV-1 preferred integration sites. The subsequences on the left and right flanking from the integration site were considered as the two views, and statistically significant relationships were established between these two views to elucidate the viral preference as an important factor for the correlation.

Electronic and mechanical properties of ZnX (X = S, Se and Te)—An ab initio study

Zinc chalcogenides (ZnX, X = S, Se and Te) have been increasing attention as wide and direct band gap semiconductor for blue and ultraviolet optical devices. This paper analyzes electronic and mechanical properties of these materials by ab initio pseudo‐potential method that uses non conserving pseudopotentials in fully nonlocal form, as implemented in SIESTA code. In this approach the local density approximation (LDA) is used for the exchange‐correlation (XC) potential. The calculations are given for band gap, elastic constants (C11, C12 and C44), shear modulus, and Youngs modulus. The results are in very good agreement with previous theoretical calculations and available experimental data.

Ab Initio Study of Electronic, Structural, Thermal and Mechanical Characterization of Cadmium Chalcogenides

Based on Density Functional Theory, we have applied Full Potential Augmented Plane Wave plus local orbital method (FAPW+lo)to study the electronic, structural, optical, thermal and mechanical properties of some semiconducting materials. In this paper we discuss the Zinc blende, CdX (X = S, Se and Te) compounds with the full-potential linear-augmented plane wave (FP-LAPW) method within the framework of the density functional theory (DFT) for electronic, structural, thermal and mechanical properties using the WIEN2k code. For the purpose of exchange-correlation energy (Exc) determination in Kohn–Sham calculation, the standard local density approximation (LDA) formalism is utilized. Murnaghans equation of state (EOS) is used for volume optimization by minimizing the total energy with respect to the unit cell volume. The calculated lattice parameters and thermal parameters are in good agreement with other theoretical calculations as well as available experimental data.