Search

In the present investigation, a high intense ultra-short pulse configuration has been proposed for plasma induced THz generation in carbon nano tubes. When a high intense ultra-short electromagnetic wave interacts with the periodically structured carbon nano tubes possessing second order susceptibility, the electromagnetic wave imparts oscillatory velocities to electrons that produce the heat. The generation of excess heat may deform the structure of the carbon nano tubes which lead to the reduction in the efficiency of THz generation. Therefore, the pulse parameters evolution such as normalized energy of the pulse, pulse width, position of the pulse center and reflectivity coefficient of the medium is investigated theoretically on plasma generation. The outcome of the theoretically investigated reveals that the increment in the heating rate can be caused by decrease in the pulse width, increment in reflectivity coefficient and the pulse peak power. Finally, an array of ultra-short pulse configurations has been proposed for efficient THz generation. The present work is helpful to regulate the heating of nanostructure during ultra-short pulse interaction.

Brahma related gene product 1 (BRG1) is an ATPase that drives the catalytic activity of a subset of the mammalian SWI/SNF chromatin remodeling enzymes. BRG1 is overexpressed in most human breast cancer tumors without evidence of mutation and is required for breast cancer cell proliferation. We demonstrate that knockdown of BRG1 sensitized triple negative breast cancer cells to chemotherapeutic drugs used to treat breast cancer. An inhibitor of the BRG1 bromodomain had no effect on breast cancer cell viability, but an inhibitory molecule that targets the BRG1 ATPase activity recapitulated the increased drug efficacy observed in the presence of BRG1 knockdown. We further demonstrate that inhibition of BRG1 ATPase activity blocks the induction of ABC transporter genes by these chemotherapeutic drugs and that BRG1 binds to ABC transporter gene promoters. This inhibition increased intracellular concentrations of the drugs, providing a likely mechanism for the increased chemosensitivity. Since ABC transporters and their induction by chemotherapy drugs are a major cause of chemoresistance and treatment failure, these results support the idea that targeting the enzymatic activity of BRG1 would be an effective adjuvant therapy for breast cancer.

A scheme of terahertz generation, employing carbon nanotubes (CNTs) embedded metal surface is proposed. The surface is irradiated by two laser beams at angle of incidence θ. The lasers exert a ponderomotive force on CNT electrons at the beat frequency ω=ω1-ω2 and produce a nonlinear current, turning the nanotubes into an array of antennae emitting beat frequency THz radiation. The THz field is resonantly enhanced at the plasmon resonance, ω = ω p β / 2 , where ωp is the plasma frequency of the CNT electrons and β is a parameter that characterizes the metallic susceptibility of the CNTs. The collisions are a limiting factor and cause heating of CNTs.

The dwindling fossil fuels have impressed upon the need of finding alternative energy sources. The biofuels derived from renewable resources are an interesting option which is being extensively researched. Biodiesel from non edible plant oils has emerged on the scene which can meet future energy demand. Jatropha curcas, a plant well adapted to semi arid condition is being seen as the source for biodiesel production. Many aspects of this plant have been studied right from its adaptation to genetic improvement. There are many reports where studies have been made on the variability at molecular level. This review deals with the biodiesel production from Jatropha at large and finally on the need of finding other plant sources that can serve the purpose of biodiesel production in the coming times.