73 research outputs found

    Intelligent Decision Making Using Evolutionary System for Optimizing Product-Mix Model

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    The development and deployment of managerial decision support system represents an emerging trend in the business and organizational field in which the increased application of Decision Support Systems (DSS) can be compiling by Intelligent Systems (IS). Decision Support Systems (DSS) are a specific class of computerized information system that supports business and organizational decision-making activities. A properly designed DSS is an interactive software-based system intended to help decision makers compile useful information from raw data, documents, personal knowledge, and/or business models to identify and solve problems and make decisions. Competitive business pressures and a desire to leverage existing information technology investments have led many firms to explore the benefits of evolutionary system data management solutions such as Particle Swarm Optimization (PSO) and Genetic Algorithm (GA). This study proposes a new model for product mix problem based on evolutionary system for optimizing constraint values as well as objective function. The formulations of the objective function for the minimization problem. This technology is designed to help businesses to finding multi objective functions

    Neighborhood Detection in Mobile Ad-Hoc Network Using Colored Petri Net

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    Colored Petri Nets (CPNs) [2] is a language for the modeling and validation of systems in which concurrency, communication [6], and synchronization play a major role. Colored Petri Nets is a discrete-event modeling language combining Petri nets with the functional programming language Standard ML. Petri nets provide the foundation of the graphical notation and the basic primitives for modeling concurrency, communication, and synchronization. Standard ML provides the primitives for the definition of data types, describing data manipulation, and for creating compact and parameterizable models. A CPN model of a system is an executable model representing the states of the system and the events (transitions) that can cause the system to change state [4]. The CPN language makes it possible to organize a model as a set of modules, and it includes a time concept for representing the time taken to execute events in the modeled system. In a mobile ad-hoc network(MANET) mobile nodes directly send messages to each other via wireless transmission. A node can send a message to another node beyond its transmission range by using other nodes as relay points, and thus a node can function as a router [1]. Typical applications of MANETS include defense systems such as battlefield survivability and disaster recovery. The research on MANETs originates from part of the Advanced Research Projects Agency(ARPA) project in the 1970s [1]. With the explosive growth of the Internet and mobile communication networks, challenging requirements have been introduced into MANETs and designing routing protocols has become more complex. One approach for ensuring correctness of an existing routing protocol is to create a formal model for the protocol and analyze the model to determine if indeed the protocol provides the defined service correctly. Colored Petri Nets are a suitable modeling language for this purpose as it can conveniently express non-determinism, concurrency and different levels of abstraction that are inherent in routing protocols. However, it is not easy to build a CPN model of a MANET because a node can move in and out of its transmission range and thus the MANET‟s topology dynamically changes. In this paper we propose an algorithm for addressing such mobility problem of a MANET [1]. Using this algorithm a node can find its neighbors ,which are dynamically changing, at any instant of time

    Strong and weak hydrogen bonds in drug-DNA complexes: a statistical analysis

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    A statistical analysis of strong and weak hydrogen bonds in the minor groove of DNA was carried out for a set of 70 drug-DNA complexes. The terms "strong" and "weak" pertain to the inherent strengths and weakness of the donor and acceptor fragments rather than to any energy considerations. The dataset was extracted from the protein data bank (PDB). The analysis was performed with an in-house software, hydrogen bond analysis tool (HBAT). In addition to strong hydrogen bonds such as O-H···O and N-H···O, the ubiquitous presence of weak hydrogen bonds such as C-H···O is implicated in molecular recognition. On an average, there are 1.4 weak hydrogen bonds for every strong hydrogen bond. For both categories of interaction, the N(3) of purine and the O(2) of pyrimidine are favoured acceptors. Donor multifurcation is common with the donors generally present in the drug molecules, and shared by hydrogen bond acceptors in the minor groove. Bifurcation and trifurcation are most commonly observed. The metrics for strong hydrogen bonds are consistent with established trends. The geometries are variable for weak hydrogen bonds. A database of recognition geometries for 26 literature amidinium-based inhibitors of Human African Trypanosomes (HAT) was generated with a docking study using seven inhibitors which occur in published crystal structures included in the list of 70 complexes mentioned above, and 19 inhibitors for which the drug-DNA complex crystal structures are unknown. The virtual geometries so generated correlate well with published activities for these 26 inhibitors, justifying our assumption that strong and weak hydrogen bonds are optimized in the active site

    Strong and weak hydrogen bonds in the protein-ligand interface

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    The characteristics of NH···O, OH···O, and CH···O hydrogen bonds and other weak intermolecular interactions are analyzed in a large and diverse group of 251 protein-ligand complexes using a new computer program that was developed in-house for this purpose. The interactions examined in the present study are those which occur in the active sites, defined here as a sphere of 10 Å radius around the ligand. Notably, NH···O and OH···O bonds tend towards linearity. Multifurcated interactions are especially common, especially multifurcated acceptors, and the average degree of furcation is 2.6 hydrogen bonds per furcated acceptor. A significant aspect of this study is that we have been able to assess the reliability of hydrogen bond geometry as a function of crystallographic resolution. Thresholds of 2.3 and 2.0 Å are established for strong and weak hydrogen bonds, below which hydrogen bond geometries may be safely considered for detailed analysis. Interactions involving water as donor or acceptor, and CH···O bonds with Gly and Tyr as donors are ubiquitous in the active site. A similar trend was observed in an external test set of 233 protein-ligand complexes belonging to the kinase family. Weaker interactions like XH···∏ (X = C, N, O) and those involving halogen atoms as electrophiles or nucleophiles have also been studied. We conclude that the strong and weak hydrogen bonds are ubiquitous in protein-ligand recognition, and that with suitable computational tools very large numbers of strong and weak intermolecular interactions in the ligand-protein interface may be analyzed reliably. Results confirm earlier trends reported previously by us but the extended nature of the present data set mean that the observed trends are more reliable

    Meiotic failure in cyclin A1-deficient mouse spermatocytes triggers apoptosis through intrinsic and extrinsic signaling pathways and 14-3-3 proteins

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    Cyclin A1 (Ccna1), a member of the mammalian A type cyclins, is most abundantly expressed in spermatocytes and is essential for spermatogenesis in the mouse. Ccna1- deficient spermatocytes arrest at late meiotic prophase and undergo apoptosis. To further delineate the mechanisms and key factors involved in this process, we have examined changes in expression of genes involved in both intrinsic and extrinsic signaling pathways that trigger apoptosis in the mutant spermatocytes. Our results show that both pathways are involved, and that the factors involved in the intrinsic pathway were expressed earlier than those involved in the extrinsic pathway. We have also begun to identify in vivo Ccna1- interacting proteins, using an unbiased biochemical approach, and identified 14-3-3, a key regulator of apoptosis, as a Ccna1-interacting protein. Expression levels of 14-3-3 proteins remain unchanged between wild type and mutant testes but there were differences in the subcellular distribution. In wild type control, 14-3-3 is detected in both cytosolic and nuclear fractions whereas it is restricted to the cytoplasm in mutant testes. This differential distribution of 14-3-3 may contribute to the induction of apoptosis in Ccna1-deficient spermatocytes. These results provide insight into the apoptotic mechanisms and pathways that are triggered when progression through the meiotic cell cycle is defective in male gametogenesis

    Gpr17 deficiency in POMC neurons ameliorates the metabolic derangements caused by long-term high-fat diet feeding

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    BACKGROUND: Proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARH) control energy homeostasis by sensing hormonal and nutrient cues and activating secondary melanocortin sensing neurons. We identified the expression of a G protein-coupled receptor, Gpr17, in the ARH and hypothesized that it contributes to the regulatory function of POMC neurons on metabolism. METHODS: In order to test this hypothesis, we generated POMC neuron-specific Gpr17 knockout (PGKO) mice and determined their energy and glucose metabolic phenotypes on normal chow diet (NCD) and high-fat diet (HFD). RESULTS: Adult PGKO mice on NCD displayed comparable body composition and metabolic features measured by indirect calorimetry. By contrast, PGKO mice on HFD demonstrated a sexually dimorphic phenotype with female PGKO mice displaying better metabolic homeostasis. Notably, female PGKO mice gained significantly less body weight and adiposity (p < 0.01), which was associated with increased energy expenditure, locomotor activity, and respiratory quotient, while males did not have an overt change in energy homeostasis. Though PGKO mice of both sexes had comparable glucose and insulin tolerance, detailed analyses of liver gene expression and serum metabolites indicate that PGKO mice could have reduced gluconeogenesis and increased lipid utilization on HFD. To elucidate the central-based mechanism(s) underlying the better-preserved energy and glucose homeostasis in PGKO mice on HFD, we examined the electrophysiological properties of POMC neurons and found Gpr17 deficiency led to increased spontaneous action potentials. Moreover, PGKO mice, especially female knockouts, had increased POMC-derived alpha-melanocyte stimulating hormone and beta-endorphin despite a comparable level of prohormone POMC in their hypothalamic extracts. CONCLUSIONS: Gpr17 deficiency in POMC neurons protects metabolic homeostasis in a sex-dependent manner during dietary and aging challenges, suggesting that Gpr17 could be an effective anti-obesity target in specific populations with poor metabolic control

    Mammalian E-type Cyclins Control Chromosome Pairing, Telomere Stability and CDK2 Localization in Male Meiosis

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    Loss of function of cyclin E1 or E2, important regulators of the mitotic cell cycle, yields viable mice, but E2-deficient males display reduced fertility. To elucidate the role of E-type cyclins during spermatogenesis, we characterized their expression patterns and produced additional deletions of Ccne1 and Ccne2 alleles in the germline, revealing unexpected meiotic functions. While Ccne2 mRNA and protein are abundantly expressed in spermatocytes, Ccne1 mRNA is present but its protein is detected only at low levels. However, abundant levels of cyclin E1 protein are detected in spermatocytes deficient in cyclin E2 protein. Additional depletion of E-type cyclins in the germline resulted in increasingly enhanced spermatogenic abnormalities and corresponding decreased fertility and loss of germ cells by apoptosis. Profound meiotic defects were observed in spermatocytes, including abnormal pairing and synapsis of homologous chromosomes, heterologous chromosome associations, unrepaired double-strand DNA breaks, disruptions in telomeric structure and defects in cyclin-dependent-kinase 2 localization. These results highlight a new role for E-type cyclins as important regulators of male meiosis

    Evaluation of CSF and plasma biomarkers of brain melanocortin activity in response to caloric restriction in humans

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    The melanocortin neuronal system, which consists of hypothalamic proopiomelanocortin (POMC) and agouti-related protein (AgRP) neurons, is a leptin target that regulates energy balance and metabolism, but studies in humans are limited by a lack of reliable biomarkers to assess brain melanocortin activity. The objective of this study was to measure the POMC prohormone and its processed peptide, β-endorphin (β-EP), in cerebrospinal fluid (CSF) and AgRP in CSF and plasma after calorie restriction to validate their utility as biomarkers of brain melanocortin activity. CSF and plasma were obtained from 10 lean and obese subjects after fasting (40 h) and refeeding (24 h), and from 8 obese subjects before and after 6 wk of dieting (800 kcal/day) to assess changes in neuropeptide and hormone levels. After fasting, plasma leptin decreased to 35%, and AgRP increased to 153% of baseline. During refeeding, AgRP declined as leptin increased; CSF β-EP increased, but POMC did not change. Relative changes in plasma and CSF leptin were blunted in obese subjects. After dieting, plasma and CSF leptin decreased to 46% and 70% of baseline, CSF POMC and β-EP decreased, and plasma AgRP increased. At baseline, AgRP correlated negatively with insulin and homeostasis model assessment (HOMA-IR), and positively with the Matsuda index. Thus, following chronic calorie restriction, POMC and β-EP declined in CSF, whereas acutely, only β-EP changed. Plasma AgRP, however, increased after both acute and chronic calorie restriction. These results support the use of CSF POMC and plasma AgRP as biomarkers of hypothalamic melanocortin activity and provide evidence linking AgRP to insulin sensitivity

    RAD9 deficiency enhances radiation induced bystander DNA damage and transcriptomal response

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    Background Radiation induced bystander effects are an important component of the overall response of cells to irradiation and are associated with human health risks. The mechanism responsible includes intra-cellular and inter-cellular signaling by which the bystander response is propagated. However, details of the signaling mechanism are not well defined. Methods We measured the bystander response of Mrad9 +/+ and Mrad9 −/− mouse embryonic stem cells, as well as human H1299 cells with inherent or RNA interference-mediated reduced RAD9 levels after exposure to 1 Gy α particles, by scoring chromosomal aberrations and micronuclei formation, respectively. In addition, we used microarray gene expression analyses to profile the transcriptome of directly irradiated and bystander H1299 cells. Results We demonstrated that Mrad9 null enhances chromatid aberration frequency induced by radiation in bystander mouse embryonic stem cells. In addition, we found that H1299 cells with reduced RAD9 protein levels showed a higher frequency of radiation induced bystander micronuclei formation, compared with parental cells containing inherent levels of RAD9. The enhanced bystander response in human cells was associated with a unique transcriptomic profile. In unirradiated cells, RAD9 reduction broadly affected stress response pathways at the mRNA level; there was reduction in transcript levels corresponding to genes encoding multiple members of the UVA-MAPK and p38MAPK families, such as STAT1 and PARP1, suggesting that these signaling mechanisms may not function optimally when RAD9 is reduced. Using network analysis, we found that differential activation of the SP1 and NUPR1 transcriptional regulators was predicted in directly irradiated and bystander H1299 cells. Transcription factor prediction analysis also implied that HIF1α (Hypoxia induced factor 1 alpha) activation by protein stabilization in irradiated cells could be a negative predictor of the bystander response, suggesting that local hypoxic stress experienced by cells directly exposed to radiation may influence whether or not they will elicit a bystander response in neighboring cells

    Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

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