Theoretical Study of Physisorption of Nucleobases on Boron Nitride Nanotubes: A New Class of Hybrid Nano-Bio Materials

We investigate the adsorption of the nucleic acid bases, adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U) on the outer wall of a high curvature semiconducting single-walled boron nitride nanotube (BNNT) by first principles density functional theory calculations. The calculated binding energy shows the order: G>A\approxC\approxT\approxU implying that the interaction strength of the (high-curvature) BNNT with the nucleobases, G being an exception, is nearly the same. A higher binding energy for the G-BNNT conjugate appears to result from a stronger hybridization of the molecular orbitals of G and BNNT, since the charge transfer involved in the physisorption process is insignificant. A smaller energy gap predicted for the G-BNNT conjugate relative to that of the pristine BNNT may be useful in application of this class of biofunctional materials to the design of the next generation sensing devices.Comment: 17 pages 6 figure

A Study on Factors Influencing Investment Decisions of Retail Investors in VUCA World

In this paper, we seek to identify the factors influencing the investment decision of individual investors. Further, in the existing pandemic situation, which will cover the scope of the VUCA environment, it is important to understand the factors influencing investor’s investment decision. For this purpose, we used exploratory factor analysis to group the factors affecting an investor’s investment decision. Based on the findings, we identified four factors influencing investment preferences and the reliability of these factors are supported by strong statistical measure

Dynamical instability and Fermi surface topology in Ni\u3csub\u3e2\u3c/sub\u3eFeGa from first principles

The phonon spectrum of stoichiometric Heusler alloy Ni2FeGa is calculated for the high-temperature cubic austenite phase by using first-principles density functional perturbation theory. We also compute the elastic constants of the alloy from the initial slopes of the acoustic phonon branch. The TA2 phonon branch along [110] direction shows softening with a minimum dip at ζ=0.58 which indicates the possibility of modulated phases prior to martensitic transformation. We also map the Fermi surface of this alloy both in 3D and 2D to check the presence of any nesting vectors. The observed nesting parameter is in good agreement with the above value of the wave vector in the [110] direction where phonon softening occurs

Development of a high performance parallel computing platform and its use in the study of nanostructures : clusters, sheets and tubes .

Small clusters of gallium oxide, technologically important high temperature ceramic, together with interaction of nucleic acid bases with graphene and small-diameter carbon nanotube are focus of first principles calculations in this work. A high performance parallel computing platform is also developed to perform these calculations at Michigan Tech. First principles calculations are based on density functional theory employing either local density or gradient-corrected approximation together with plane wave and gaussian basis sets. The bulk Ga2O3 is known to be a very good candidate for fabricating electronic devices that operate at high temperatures. To explore the properties of Ga2O3 at nonoscale, we have performed a systematic theoretical study on the small polyatomic gallium oxide clusters. The calculated results find that all lowest energy isomers of GamOn clusters are dominated by the Ga-O bonds over the metal-metal or the oxygen-oxygen bonds. Analysis of atomic charges suggest the clusters to be highly ionic similar to the case of bulk Ga2O3. In the study of sequential oxidation of these slusters starting from Ga2O, it is found that the most stable isomers display up to four different backbones of constituent atoms. Furthermore, the predicted configuration of the ground state of Ga2O is recently confirmed by the experimental result of Neumark\u27s group. Guided by the results of calculations the study of gallium oxide clusters, performance related challenge of computational simulations, of producing high performance computers/platforms, has been addressed. Several engineering aspects were thoroughly studied during the design, development and implementation of the high performance parallel computing platform, rama, at Michigan Tech. In an attempt to stay true to the principles of Beowulf revolutioni, the rama cluster was extensively customized to make it easy to understand, and use - for administrators as well as end-users. Following the results of benchmark calculations and to keep up with the complexity of systems under study, rama has been expanded to a total of sixty four processors. Interest in the non-covalent intereaction of DNA with carbon nanotubes has steadily increased during past several years. This hybrid system, at the junction of the biological regime and the nanomaterials world, possesses features which make it very attractive for a wide range of applicatioins. Using the in-house computational power available, we have studied details of the interaction between nucleic acid bases with graphene sheet as well as high-curvature small-diameter carbon nanotube. The calculated trend in the binding energies strongly suggests that the polarizability of the base molecules determines the interaction strength of the nucleic acid bases with graphene. When comparing the results obtained here for physisorption on the small diameter nanotube considered with those from the study on graphene, it is observed that the interaction strength of nucleic acid bases is smaller for the tube. Thus, these results show that the effect of introducing curvature is to reduce the binding energy. The binding energies for the two extreme cases of negligible curvature (i.e. flat graphene sheet) and of very high curvature (i.e. small diameter nanotube) may be considered as upper and lower bounds. This finding represents an important step towards a better understanding of experimentally observed sequence-dependent interaction of DNA with Carbon nanotubes

Label-free electrical detection of DNA hybridization using carbon nanotubes and graphene

The interface between biosystems and nanomaterials is emerging for detection of various biomolecules and subtle cellular activities. In particular, the development of cost-effective and sequence-selective DNA detection is urgent for the diagnosis of genetic or pathogenic diseases. Graphene-based nanocarbon materials, such as carbon nanotubes and thin graphene layers, have been employed as biosensors because they are biocompatible, extraordinarily sensitive, and promising for large-area detection. Electrical and label-free detection of DNA can be achieved by monitoring the conductance change of devices fabricated from these carbon materials. Here, the recent advances in this research area are briefly reviewed. The key issues and perspectives of future development are also discussed

RESEARCH ARTICLE ARTICALTICLE International Journal of Pharma and Bio Sciences GENETICS CYTOGENETIC ANALYSIS OF MICRONUCLEI, SISTER CHROMATID EXCHANGE AND CHROMOSOMAL ABERRATIONS IN PAN MASALA CHEWERS

Pan Masala (PM) chewing is very dangerous for health but it is becoming very popular day by day. PM is a dried powdered mixture containing ingredients like areca nut, catechu, lime, cardamom and flavouring agents. It is consumed abundantly by Indians and is also exported to Western countries. A cytogenetic study to assess the micronucleus (MN), sister chromatid exchange (SCE) levels and chromosomal aberrations among (CA) 60 pan chewers and 60 non-chewers was conducted in Chennai, Tamil Nadu. In the present cytogenetic monitoring study, analysis of MN was significantly higher (15.82 ± 1.31) in chewers than controls (4.82 ± 1.47) (P < 0.001) and SCE also was significantly higher in chewers (9.23 ± 2.12) than controls (4.80±1.11) (P < 0.001). In exfoliated buccal mucosa and chromosome analysis (CA), frequency of chromatid type aberrations is lower in controls than chewers such as gaps (0.90 % v. 1.83%) breaks (0.47 % v. 1.77%), exchanges (0.02 % v. 0.18) and acentric fragments (0.20 % v. 0.90%). The increased percentage of aberrations found among pan chewers is significantly higher when compared to that of the controls. Isochromatid aberrations also increased significantly such as gaps (0.12 % v. 0.97%) breaks (0.07 % v. 0.80%), acentric fragments (0.05 % v. 0.23%), dicentrics (0.02 % v. 0.63%), and these were estimated in th

Delineate Subsurface and Groundwater Investigation of Ongur Watershed, South India

The electrical resistivity technique is extremely supportive to investigate the nature of subsurface lithology by understand the variations in their electrical properties. The Vertical Electrical Sounding (VES) technique by Schlumberger electrode array applied in 77 Locations at Ongur River Sub Basin in Tamil Nadu, India. The Signal stacking Resistivity Meter Model SSR-MP-ATS has been applied to gather the VES data by employed a Schlumberger array, one end current electrode (AB/2) ranging from 1 to 100 m, other side placing potential electrode (MN) from 0.5 to 10 m. The concept of the VES data interpreting is the foundation of IPI2Win. It means for a VES data are treated as a unity representing the geological structure of the Ongur River watershed. The output Geo-electrical layers, iso- resistivities and thickness of this area were prepared in spatial maps by using ARCGIS software. Consequently, the following zones with different resistivity values are detected consequent to different formations: (1) identification of lithology Ongur River Sub Basin, (2) layer saturated with fresh groundwater, (3) determine saltwater horizon

LUNAR: Automated Input Generation and Analysis for Reactive LAMMPS Simulations

Generating simulation-ready molecular models for the LAMMPS molecular dynamics (MD) simulation software package is a difficult task and impedes the more widespread and efficient use of MD in materials design and development. Fixed-bond force fields generally require manual assignment of atom types, bonded interactions, charges, and simulation domain sizes. A new LAMMPS pre- and postprocessing toolkit (LUNAR) is presented that efficiently builds molecular systems for LAMMPS. LUNAR automatically assigns atom types, generates bonded interactions, assigns charges, and provides initial configuration methods to generate large molecular systems. LUNAR can also incorporate chemical reactivity into simulations by facilitating the use of the REACTER protocol. Additionally, LUNAR provides postprocessing for free volume calculations, cure characterization calculations, and property predictions from LAMMPS thermodynamic outputs. LUNAR has been validated via building and simulation of pure epoxy and cyanate ester polymer systems with a comparison of the corresponding predicted structures and properties to benchmark values, including experimental results from the literature. LUNAR provides the tools for the computationally driven development of next-generation composite materials in the Integrated Computational Materials Engineering (ICME) and Materials Genome Initiative (MGI) frameworks. LUNAR is written in Python with the usage of NumPy and can be used via a graphical user interface, a command line interface, or an integrated design environment. LUNAR is freely available via GitHub