30 research outputs found

    FUZZY INVENTORY MODEL FOR ITEMS WITH WEIBULL DISTRIBUTION DETERIORATION, POWER DEMAND, LINEAR HOLDING COST, SALVAGE COST AND PARTIAL BACKLOGGING

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    The objective of this research article is to develop an inventory model which incorporates power pattern demand, Weibull distribution deterioration, shortages and partial backlogging of orders. Holding cost is taken as time dependent and deteriorated items are assumed to have a salvage value. The cost parameters are fuzzified and the total cost is defuzzified using Graded mean representation, signed distance and centroid methods. The values obtained by these methods are compared with the help of numerical examples. The convexity of the cost function is depicted graphically. Sensitivity analysis is performed to study the effect of change in some parameters. Keywords: Inventory, Power demand, Partial backlogging, Deterioration, Triangular Fuzzy Number, Defuzzification, Graded mean represented method, Signed Distance Method, centroid method

    Photo-antagonism of the GABAA receptor

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    Neurotransmitter receptor trafficking is fundamentally important for synaptic transmission and neural network activity. GABAA receptors and inhibitory synapses are vital components of brain function, yet much of our knowledge regarding receptor mobility and function at inhibitory synapses is derived indirectly from using recombinant receptors, antibody-tagged native receptors and pharmacological treatments. Here we describe the use of a set of research tools that can irreversibly bind to and affect the function of recombinant and neuronal GABAA receptors following ultraviolet photoactivation. These compounds are based on the competitive antagonist gabazine and incorporate a variety of photoactive groups. By using site-directed mutagenesis and ligand-docking studies, they reveal new areas of the GABA binding site at the interface between receptor β and α subunits. These compounds enable the selected inactivation of native GABAA receptor populations providing new insight into the function of inhibitory synapses and extrasynaptic receptors in controlling neuronal excitation

    Defining an Essence of Structure Determining Residue Contacts in Proteins

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    The network of native non-covalent residue contacts determines the three-dimensional structure of a protein. However, not all contacts are of equal structural significance, and little knowledge exists about a minimal, yet sufficient, subset required to define the global features of a protein. Characterisation of this “structural essence” has remained elusive so far: no algorithmic strategy has been devised to-date that could outperform a random selection in terms of 3D reconstruction accuracy (measured as the Ca RMSD). It is not only of theoretical interest (i.e., for design of advanced statistical potentials) to identify the number and nature of essential native contacts—such a subset of spatial constraints is very useful in a number of novel experimental methods (like EPR) which rely heavily on constraint-based protein modelling. To derive accurate three-dimensional models from distance constraints, we implemented a reconstruction pipeline using distance geometry. We selected a test-set of 12 protein structures from the four major SCOP fold classes and performed our reconstruction analysis. As a reference set, series of random subsets (ranging from 10% to 90% of native contacts) are generated for each protein, and the reconstruction accuracy is computed for each subset. We have developed a rational strategy, termed “cone-peeling” that combines sequence features and network descriptors to select minimal subsets that outperform the reference sets. We present, for the first time, a rational strategy to derive a structural essence of residue contacts and provide an estimate of the size of this minimal subset. Our algorithm computes sparse subsets capable of determining the tertiary structure at approximately 4.8 Å Ca RMSD with as little as 8% of the native contacts (Ca-Ca and Cb-Cb). At the same time, a randomly chosen subset of native contacts needs about twice as many contacts to reach the same level of accuracy. This “structural essence” opens new avenues in the fields of structure prediction, empirical potentials and docking

    Inference of Co-Evolving Site Pairs: an Excellent Predictor of Contact Residue Pairs in Protein 3D structures

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    Residue-residue interactions that fold a protein into a unique three-dimensional structure and make it play a specific function impose structural and functional constraints on each residue site. Selective constraints on residue sites are recorded in amino acid orders in homologous sequences and also in the evolutionary trace of amino acid substitutions. A challenge is to extract direct dependences between residue sites by removing indirect dependences through other residues within a protein or even through other molecules. Recent attempts of disentangling direct from indirect dependences of amino acid types between residue positions in multiple sequence alignments have revealed that the strength of inferred residue pair couplings is an excellent predictor of residue-residue proximity in folded structures. Here, we report an alternative attempt of inferring co-evolving site pairs from concurrent and compensatory substitutions between sites in each branch of a phylogenetic tree. First, branch lengths of a phylogenetic tree inferred by the neighbor-joining method are optimized as well as other parameters by maximizing a likelihood of the tree in a mechanistic codon substitution model. Mean changes of quantities, which are characteristic of concurrent and compensatory substitutions, accompanied by substitutions at each site in each branch of the tree are estimated with the likelihood of each substitution. Partial correlation coefficients of the characteristic changes along branches between sites are calculated and used to rank co-evolving site pairs. Accuracy of contact prediction based on the present co-evolution score is comparable to that achieved by a maximum entropy model of protein sequences for 15 protein families taken from the Pfam release 26.0. Besides, this excellent accuracy indicates that compensatory substitutions are significant in protein evolution.Comment: 17 pages, 4 figures, and 4 tables with supplementary information of 5 figure

    Antioxidant status in polycystic end-staged renal diseased patients and antihemolytic effect of <i style="">Boerhaavia diffusa</i>

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    269-272Chronic renal failure (CRF) induces anaemia by shortening the life-span of erythrocytes, due to an increase in oxidative stress, which is considered to be one of the major risk factors in CRF patients undergoing hemodialysis. In the present study, the antioxidant status of the end-staged renal disease (ESRD) patients was investigated. The antihemolytic activity of Boerhaavia diffusa on the erythrocytes of the patients was also studied. Protein, lipid peroxides (LPO), reduced glutathione (GSH) levels and glutathione peroxidase (GPX) and glutathione-S-transferase (GST) activities were measured in the hemolysate from 55 polycystic ESRD patients (Group II) and compared with normal subjects (Group I). The antioxidant status was found to be significantly reduced in the patients as compared to normal healthy volunteers, due to increased oxidative stress. Also, aqueous extract of B. diffusa showed a significant antihemolytic activity on the erythrocytes of the polycystic ESRD patients.

    Correlation of the side-chain hubs with the functional residues in DNA binding protein structures

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    The structure networks of DNA-binding proteins have been constructed and analyzed. The detailed analysis of the networks indicates a strong relation between the positions of the residues interacting with DNA and those that form extensive interactions within the protein structure (called hubs). This study shows that the functional residues in these proteins are held in place by efficient scaffolding of the structure using side-chain interactions, thus highlighting the role of these side-chain hubs with respect to the functional residues in the protein structure

    Designing Mobility using Distance Routing Effect Algorithm

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    An ad-hoc network signifies a solution designed for a specific problem or task and it is an independent network that provides usually temporary peer-to-peer connectivity without relying on a complete network infrastructure. It allows users to communicate while forming a temporary network, without any form of federal administration. Each node participating in the network performs the host and router function, and willing to forward packets for other nodes. For this a routing protocol is needed. An approach utilizes the individuality of such a network a DISTANCE ROUTING EFFECT ALGORITHM FOR MOBILITY. The protocol uses the distance effect and the mobility rate as a means to assure routing accuracy. When data needs to be exchanged between nodes, the directional algorithm sends messages in the recorded direction of the destination node, guaranteeing the delivery by following the direction. The improved algorithm suggested within this paper includes an additional parameter, direction of travel, as a means of determining the location of a destination node. When data needs to be exchanged between two nodes, the directional algorithm sends messages in the recorded direction of the destination node, guaranteeing the delivery. The result is an enhancement to the delivery ratio, sent to the received packet. This allows the reduction in the number of control packets that need to be distributed
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