Surface effects in nanocrystalline silicon

Exposure to ammonia (NH₃) increases the dark current (DC) in nanocrystalline silicon. Light soaking (LS) for short periods also enhances the dark current, which remains at a high value for a long time. Pumping alone is unable to restore the initial annealed state, but annealing brings it back. The final state obtained by LS and NH₃ exposure depends on the order in which they are performed. Evaporated selenium (Se) deposited on nanocrystalline silicon decreases the DC. These effects cannot be explained entirely by the presence of a-Si : H alone, in our sample. DC and photoluminescence (PL) measurements indicate the presence of two types of center in our sample, which behave differently when exposed to NH₃.     

Binding free energy calculations of galectin-3-ligand interactions

Galectins show remarkable binding specificity towards ß-galactosides.A recently developed method for calculating binding free energiesbetween a protein and its substrates has been used to evaluatethe binding specificity of galectin-3. Five disaccharides anda tetrasaccharide were used as the substrates. The calculatedbinding free energies agree quite well with the experimentaldata and the ranking of binding affinities is well reproduced.For all the six protein–ligand complexes it was observedthat electrostatic interactions oppose binding whereas the non-polarcontributions drive complex formation. The observed bindingspecificity of galectin-3 for galactosides rather than glucosidesis discussed in light of our results.     

CAD on geocomposite vertical strip drains

In recent years, an increasing need has arisen for various types of construction on sites underlain by soft cohesive soils. In such cases, some methods of soil improvement are usually required to provide adequate bearing capacity and tolerable postconstruction total and differential settlements. These goals often may be achieved by precompression or preloading the site prior to construction. Precompression and preloading are frequently used in combination with vertical drains, especially in very thick soft deposits, otherwise the time required for consolidation may be unacceptably long or the instability of the foundation may be a serious concern. Therefore, the vertical geocomposite (jute and coir) drain may be used to accelerate the settlement of soil thereby making the site available for use in the shortest time. The computer program and the design chart for determining the spacing between geocomposite drains are presented. This technique is generally useful for embankment construction, tank foundation, underwater construction and landfill areas. Two projects (Haldia in West Bengal and Vashi Station Complex in Bombay) have utilized the application of geocomposite drains reported in this paper.     

Compact wideband bandpass filter

Designing wideband bandpass filters (BPF) with parallel-coupled microstrip lines requires tight coupling resulting in close separation between the lines and difficulty of fabrication. Here, it is shown that the etched slots in the ground plane of the parallel coupled lines can significantly increase the coupling. This technique has been extended to realize ultra-wideband BPFs having 3-dB fractional bandwidth greater than 100% and low insertion loss in the passband.     

Testing viability of cross subsidy using time-variant price elasticities of industrial demand for electricity: Indian experience

Indian electric tariffs are characterized by very high rates for industrial and commercial classes to permit subsidized electric consumption by residential and agricultural customers. We investigate the viability of this policy using monthly data for 1997–2003 on electric consumption by a few large industrial customers under the aegis of a small distribution company in the state of Uttar Pradesh. For a given price/cost ratio, it can be shown that if the cross-subsidizing class’ electricity demand is sufficiently elastic, increasing the class’ rates fail to recover incremental cross-subsidy necessary to support additional revenues for subsidized classes. This suboptimality is tested by individually estimating time-variant price-elasticities of demand for these industrial customers using Box-Cox and linear regressions. We find that at least for some of these customers, cross-subsidy was suboptimal prior to as late as October 2001, when rates were changed following reforms.     

Bcl-2 deregulation leads to inhibition of sodium butyrate-induced apoptosis in human colorectal carcinoma cells

Epidemiological studies have linked dietary fiber to the prevention of human colorectal cancer and suggest that short chain fatty acids such as butyric acid, which is produced by fermentation of dietary fiber in the large intestine, may be an important mediator of the protective effects of fiber. We investigated the role of Bcl-2 deregulation on the sensitivity of colorectal carcinoma cells to undergo butyrate-induced apoptosis. Here we report an inverse relationship between the levels of Bcl-2 and the sensitivity of colorectal carcinoma cell lines to undergo apoptosis in response to butyrate. Overexpression of Bcl-2 in colorectal carcinoma DiFi cells resulted in suppression of butyrate-induced apoptosis and enhanced cell survival in response to butyrate. Butyrate-induced apoptosis was accompanied by inhibition of expression of a 30 kDa protein (p30, immunorecognized by anti-Bcl-2 mAb) and this cellular effect of butyrate was inhibited by Bcl-2 overexpression. These findings suggest that deregulation of Bcl-2 in human colorectal carcinoma cells confers resistance to induction of apoptosis by butyrate, a dietary micronutrient.     

Overexpression of HER2 modulates bcl-2, bcl-XL, and tamoxifen-induced apoptosis in human MCF-7 breast cancer cells

Overexpression of HER2 in estrogen receptor (ER)-positive human breast tumors has been associated with resistance to endocrine therapy. Here we investigated the effects of HER2 on expression of apoptotic pathways and modulation of tamoxifen-induced apoptosis in ER-positive MCF-7 breast cancer cells. We report that HER2 overexpression in MCF-7 cells is accompanied by up-regulation of antiapoptotic Bcl-2 and Bcl-XL proteins and suppression of tamoxifen-induced apoptosis. In addition, human tumor cell lines that are both ER positive and overexpress HER2 also express enhanced levels of Bcl-2 compared to cells that are either ER positive or overexpress HER2 alone. Our findings suggest that possible deregulation of antiapoptotic Bcl-2 and Bcl-XL may be associated with the enhanced survival of HER2-overexpressing and ER-positive breast cancer cells treated with antiestrogens.     

Dielectric behaviour of glasses and glass ceramics in the system BaO-PbO-TiO2-B2O3-SiO2

Glasses with varying molar ratios of PbO/BaO in the system BaO-PbO-TiO₂-B₂O₃-SiO₂ were prepared keeping (BaO + PbO)/TiO₂ ratio equal to one. The glasses were ceramized by two-stage heat treatment. X-ray diffraction indicates that PbTiO₃ crystallizes in lead-rich glasses while BaTiO₃ precipitates in barium-rich compositions. Solid solution (Ba, Pb)TiO₃ does not seem to crystallize over the entire range of compositions. Simultaneous presence of PbO and BaO in the initial glass composition reduces the yield of ferroelectric phase. Dielectric properties have been interpreted in terms of microstructural features.     

Preface

Microsystem Technologies -