1-[5-Acetyl-4-(4-bromophenyl)-2,6-dimethyl-1,4-dihydropyridin-3-yl]eth anone monohydrate

The 1,4-dihydropyridine ring in the title hydrate, C17H18BrNO2 center dot H2O, has a flattened-boat conformation, and the benzene ring is occupies a position orthogonal to this [dihedral angle: 82.19 (16)degrees]. In the crystal packing, supramolecular arrays mediated by N-H center dot center dot center dot O-water and O-water-H center dot center dot center dot O-carbonyl hydrogen bonding are formed in the bc plane. A highly disordered solvent molecule is present within a molecular cavity defined by the organic and water molecules. Its contribution to the electron density was removed from the observed data in the final cycles of refinement and the formula, molecular weight and density are given without taking into account the contribution of the solvent molecule.

False Error Study of On-line Soft Error Detection Mechanisms

With technology scaling, vulnerability to soft errors in random logic is increasing. There is a need for on-line error detection and protection for logic gates even at sea level. The error checker is the key element for an on-line detection mechanism. We compare three different checkers for error detection from the point of view of area, power and false error detection rates. We find that the double sampling checker (used in Razor), is the simplest and most area and power efficient, but suffers from very high false detection rates of 1.15 times the actual error rates. We also find that the alternate approaches of triple sampling and integrate and sample method (I&S) can be designed to have zero false detection rates, but at an increased area, power and implementation complexity. The triple sampling method has about 1.74 times the area and twice the power as compared to the Double Sampling method and also needs a complex clock generation scheme. The I&S method needs about 16% more power with 0.58 times the area as double sampling, but comes with more stringent implementation constraints as it requires detection of small voltage swings.

Design of an optimal auction for sponsored search auctions

In this paper we first describe a framework to model the sponsored search auction on the web as a mechanism design problem. Using this framework, we design a novel auction which we call the OPT (optimal) auction. The OPT mechanism maximizes the search engine's expected revenue while achieving Bayesian incentive compatibility and individual rationality of the advertisers. We show that the OPT mechanism is superior to two of the most commonly used mechanisms for sponsored search namely (1) GSP (Generalized Second Price) and (2) VCG (Vickrey-Clarke-Groves). We then show an important revenue equivalence result that the expected revenue earned by the search engine is the same for all the three mechanisms provided the advertisers are symmetric and the number of sponsored slots is strictly less than the number of advertisers.

On the DC Conductivity of HV DC Cable Insulation - Cautions in using the Empirical Models

The electrical conduction in insulating materials is a complex process and several theories have been suggested in the literature. Many phenomenological empirical models are in use in the DC cable literature. However, the impact of using different models for cable insulation has not been investigated until now, but for the claims of relative accuracy. The steady state electric field in the DC cable insulation is known to be a strong function of DC conductivity. The DC conductivity, in turn, is a complex function of electric field and temperature. As a result, under certain conditions, the stress at cable screen is higher than that at the conductor boundary. The paper presents detailed investigations on using different empirical conductivity models suggested in the literature for HV DC cable applications. It has been expressly shown that certain models give rise to erroneous results in electric field and temperature computations. It is pointed out that the use of these models in the design or evaluation of cables will lead to errors.

Functional characterization of lysophosphatidic acid phosphatase from Arabidopsis thaliana

Lysophosphatidic acid (LPA) acts as a signaling molecule that regulates diverse cellular processes and it can rapidly be metabolized by phosphatase and acyltransferase LPA phosphatase gene has not been identified and characterized in plants so far The BLAST search revealed that the At3g03520 is similar to phospholipase family. and distantly related to bacterial phosphatases The conserved motif. (J)4XXXNXSFD, was identified in both At3g03520 like phospholipases and acid phosphatases In silico expression analysis of At3g03520 revealed a high expression during phosphate starvation and abiotic stresses. This gene was overexpressed in Escherichia coli and shown to posses LPA specific phosphatase activity These results Suggest that this gene possibly plays a role in signal transduction and storage lipid synthesis.

RECONNECT: A NoC for polymorphic ASICs using a low overhead single cycle router

A polymorphic ASIC is a runtime reconfigurable hardware substrate comprising compute and communication elements. It is a ldquofuture proofrdquo custom hardware solution for multiple applications and their derivatives in a domain. Interoperability between application derivatives at runtime is achieved through hardware reconfiguration. In this paper we present the design of a single cycle Network on Chip (NoC) router that is responsible for effecting runtime reconfiguration of the hardware substrate. The router design is optimized to avoid FIFO buffers at the input port and loop back at output crossbar. It provides virtual channels to emulate a non-blocking network and supports a simple X-Y relative addressing scheme to limit the control overhead to 9 bits per packet. The 8times8 honeycomb NoC (RECONNECT) implemented in 130 nm UMC CMOS standard cell library operates at 500 MHz and has a bisection bandwidth of 28.5 GBps. The network is characterized for random, self-similar and application specific traffic patterns that model the execution of multimedia and DSP kernels with varying network loads and virtual channels. Our implementation with 4 virtual channels has an average network latency of 24 clock cycles and throughput of 62.5% of the network capacity for random traffic. For application specific traffic the latency is 6 clock cycles and throughput is 87% of the network capacity.

Specific Small-Molecule Activator of Aurora Kinase A Induces Autophosphorylation in a Cell-Free System

Aurora kinases are essential for chromosomal segregation and cell division and thereby important for maintaining the proper genomic integrity. There are three classes of aurora kinases in humans: A, B, and C. Aurora kinase A is frequently overexpressed in various cancers. The link of the overexpression and tumorigenesis is yet to be understood. By employing virtual screening, we have found that anacardic acid, a pentadecane aliphatic chain containing hydroxylcarboxylic acid, from cashew nut shell liquid could be docked in Aurora kinases A and B. Remarkably, we found that anacardic acid could potently activate the Aurora kinase A mediated phosphorylation of histone H3, but at a similar concentration the activity of aurora kinase B remained unaffected in vitro. Mechanistically, anacardic acid induces the structural changes and also the autophosphorylation of the aurora kinase A to enhance the enzyme activity. This data thus indicate anacardic acid as the first small-molecule activator of Aurora kinase, which could be highly useful for probing the function of hyperactive (overexpressed) Aurora kinase A.

Synthesis and characterization of Zn1-xMnxS nanocrystalline films prepared on glass substrates

Nanocrystalline Zn1-xMnxS films (x=0.04, 0.08 and 0.12) were deposited on glass substrates at 400 K using a simple resistive thermal evaporation technique. All the deposited films were characterized by chemical, structural, morphological, optical and magnetic properties. Scanning electron microscopy and atomic force microscopy studies showed that all the films investigated were in nanocrystalline form with the grain size lying in the range 10–20 nm. All the films exhibited cubic structure and the lattice parameters increase linearly with composition. The absorption edge shifted from the higher-wavelength region to lower wavelengths with increase in Mn concentration. The magnetization increased sharply with increase of the Mn content up to x=0.08 and then decreased with further increase of the Mn content. Particularly, Zn0.92Mn0.08S concentration samples show a weak ferromagnetic nature, which might be the optimum concentration for optoelectronic and spintronic device applications.

Optimization of the distance between source and substrate for device-grade SnS films grown by the thermal evaporation technique

Tin monosulfide (SnS) films with varying distance between the source and substrate (DSS) were prepared by the thermal evaporation technique at a temperature of 300 degrees C to investigate the effect of the DSS on the physical properties. The physical properties of the as-deposited films are strongly influenced by the variation of DSS. The thickness, Sn to S at.% ratio, grain size, and root mean square (rms) roughness of the films decreased with the increase of DSS. The films grown at DSS = 10 and 15 cm exhibited nearly single-crystalline nature with low electrical resistivity. From Hall-effect measurements, it is observed that the films grown at DSS <= 15 cm have p-type conduction and the films grown at higher distances have n-type conduction due to the variation of the Sn/S ratio. The films grown at DSS = 15 cm showed higher optical band gap of 1.36 eV as compared with the films grown at other distances. The effect of the DSS on the physical properties of SnS films is discussed and reported.

The effect of halogen atom on the molecular quadratic nonlinearity of half sandwich complexes in the presence of an acceptor

Half sandwich complexes of the type [CpM(CO)(n)X] {X=Cl, Br, I; If, M=Fe, Ru; n=2 and if M=Mo; n=3} and [CpNiPPh3X] {X=Cl, Br, I} have been synthesized and their second order molecular nonlinearity (beta) measured at 1064 nm in CHCl3 by the hyper-Rayleigh scattering technique. Iron complexes consistently display larger beta values than ruthenium complexes while nickel complexes have marginally larger beta values than iron complexes. In the presence of an acceptor ligand such as CO or PPh3, the role of the halogen atom is that of a pi donor. The better overlap of Cl orbitals with Fe and Ni metal centres make Cl a better pi donor than Br or I in the respective complexes. Consequently, M-pi interaction is stronger in Fe/Ni-Cl complexes. The value of beta decreases as one goes down the halogen group. For the complexes of 4d metal ions where the metal-ligand distance is larger, the influence of pi orbital overlap appears to be less important, resulting in moderate changes in beta as a function of halogen substitution. (C) 2006 Elsevier B.V. All rights reserved.

Synthesis, Characterization and Evaluation of Cytotoxicity of New Aminophosphonic Acid Diesters in Human Leukemia Cells

A series of novel fluoroaminophosphates 4a-4j were synthesized by one-pot method in presence of tetramethylguanidine (TMG) as a catalyst and were characterized by elemental analysis, FTIR, H-1, C-13, P-31, F-19 NMR, and mass spectra. All the title compounds were evaluated forin vitro cytotoxicity against leukemic cell line derived from T-cells of leukemia patient (CEM cells) by Trypan blue exclusion and MTT assays, and these were found to exert concentration dependent cytotoxic effects. Among them 4f, 4g & 4j possessed marked cytotoxicity. 4g (with IC50 value of 6 mu M) had emerged as lead compound.

Field Reduction Electrodes for the Possible Improvement in the Pollution Flashover Performance of Porcelain Insulators

In this paper an attempt is made to study accurately, the field distribution for various types of porcelain/ceramic insulators used forhigh voltage transmission. The surface charge Simulation method is employed for the field computation. Novel field reduction electrodes are developed to reduce the maximum field around the pin region. In order to experimentally scrutinize the performance of discs with field reduction electrodes, special artificial pollution test facility was built and utilized. The experimental results show better improvement in the pollution flashover performance of string insulators.

Molten globule-like state of peanut lectin monomer retains its carbohydrate specificity - Implications in protein folding and legume lectin oligomerization

A central question in biological chemistry is the minimal structural requirement of a protein that would determine its specificity and activity, the underlying basis being the importance of the entire structural element of a protein with regards to its activity vis a vis the overall integrity and stability of the protein. Although there are many reports on the characterization of protein folding/ unfolding intermediates, with considerable secondary structural elements but substantial loss of tertiary structure, none of them have been reported to show any activity toward their respective ligands. This may be a result of the conditions under which such intermediates have been isolated or due to the importance of specific structural elements for the activity. In this paper we report such an intermediate in the unfolding of peanut agglutinin that seems to retain, to a considerable degree, its carbohydrate binding specificity and activity. This result has significant implications on the molten globule state during the folding pathway(s) of proteins in general and the quaternary association in legume lectins in particular, where precise subunit topology is required for their biologic activities.

Optimal threshold policies for admission control in communication networks via discrete parameter stochastic approximation

The problem of admission control of packets in communication networks is studied in the continuous time queueing framework under different classes of service and delayed information feedback. We develop and use a variant of a simulation based two timescale simultaneous perturbation stochastic approximation (SPSA) algorithm for finding an optimal feedback policy within the class of threshold type policies. Even though SPSA has originally been designed for continuous parameter optimization, its variant for the discrete parameter case is seen to work well. We give a proof of the hypothesis needed to show convergence of the algorithm on our setting along with a sketch of the convergence analysis. Extensive numerical experiments with the algorithm are illustrated for different parameter specifications. In particular, we study the effect of feedback delays on the system performance.

Inhibitory activity of Image -asparaginase from Mycobcacterium tuberculosis on Yoshida ascites sarcoma in rats

The antitumor activity of Image -asparagine amidohydrolases (EC 3.5.1.1) from Mycobacterium tuberculosis H37Rv and H37Ra strains has been tested on Yoshida ascites sarcoma in rats. The enzyme specific to M. tuberculosis H37Ra but not to H37Rv has proved to be effective in inhibiting the growth of the sarcoma. Comparative studies on the activity of this enzyme with that of similar enzyme from Escherichia coli B, has shown that at the same levels the former is more effective than the latter. Long-lived immunity to this tumor in A/IISc Wistar rats following treatment of tumor bearing animals with M. tuberculosis H37Ra, pH 9.6 Image -asparaginase has been observed. Immunity in these rats was demonstrated by tumor rejection and detection of humoral antibodies in the sera to the antigen of the cell-free extract of the tumor. The enzyme was ineffective in inhibiting fibrosarcoma in mice at the dose levels tested.