109 research outputs found

    Determination of Spot Price and Optimal Power Flow in Deregulated Power System

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    In this paper, determinations of spot price with optimal power flow and important factors that may affect generating companies' profit margins through wholesale electricity trading are discussed. These factors include spot price, generators' efficiencies and capabilities, types of generators owned, fuel costs, transmission losses and settling price variation. It demonstrates how proper analysis of these factors using the solutions of Optimal Power Flow (OPF), can allow companies to maximize overall revenue. And through this OPF analysis, companies will be able to determine, for example, which generators are most economical to run, best locations for generators to be situated at, and also the scheduling of generators as demand changes throughout the day. It illustrates how solutions of OPF can be used to maximize companies' revenue under different scenarios. In this paper above tasks are demonstrated on 124-bus Indian utility real-life system and results have been presented and analyzed. All simulations are performed by using Power World Simulator software. Keywords: OPF, Electricity Market, Spot Pric

    Biochemical Properties of a Novel Cysteine Protease of Plasmodium vivax, Vivapain-4

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    Plasmodium vivax affects hundreds of millions each year and results in severe morbidity and mortality. Plasmodial cysteine proteases (CPs) play crucial roles during the progression of malaria since inhibition of these molecules impairs parasite growth. These CPs might be targeted for new antimalarial drugs. We characterized a novel P. vivax CP, vivapain-4 (VX-4), which appeared to evolve differentially among primate Plasmodium species. VX-4 showed highly unique substrate preference depending on surrounding micro-environmental pH. It effectively hydrolyzed benzyloxycarbonyl-Leu-Arg-4-methyl-coumaryl-7-amide (Z-Leu-Arg-MCA) and Z-Phe-Arg-MCA at acidic pH and Z-Arg-Arg-MCA at neutral pH. Three amino acids (Ala90, Gly157 and Glu180) that delineate the S2 pocket were found to be substituted in VX-4. Alteration of Glu180 abolished hydrolytic activity against Z-Arg-Arg-MCA at neutral pH, indicating Glu180 is intimately involved in the pH-dependent substrate preference. VX-4 hydrolyzed actin at neutral pH and hemoglobin at acidic pH, and participated in plasmepsin 4 activation at neutral/acidic pH. VX-4 was localized in the food vacuoles and cytoplasm of the erythrocytic stage of P. vivax. The differential substrate preferences depending on pH suggested a highly efficient mechanism to enlarge biological implications of VX-4, including hemoglobin degradation, maturation of plasmepsin, and remodeling of the parasite architecture during growth and development of P. vivax

    ADARRI:a novel method to detect spurious R-peaks in the electrocardiogram for heart rate variability analysis in the intensive care unit

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    We developed a simple and fully automated method for detecting artifacts in the R-R interval (RRI) time series of the ECG that is tailored to the intensive care unit (ICU) setting. From ECG recordings of 50 adult ICU-subjects we selected 60 epochs with valid R-peak detections and 60 epochs containing artifacts leading to missed or false positive R-peak detections. Next, we calculated the absolute value of the difference between two adjacent RRIs (adRRI), and obtained the empirical probability distributions of adRRI values for valid R-peaks and artifacts. From these, we calculated an optimal threshold for separating adRRI values arising from artifact versus non-artefactual data. We compared the performance of our method with the methods of Berntson and Clifford on the same data. We identified 257,458 R-peak detections, of which 235,644 (91.5%) were true detections and 21,814 (8.5%) arose from artifacts. Our method showed superior performance for detecting artifacts with sensitivity 100%, specificity 99%, precision 99%, positive likelihood ratio of 100 and negative likelihood ratio <0.001 compared to Berntson’s and Clifford’s method with a sensitivity, specificity, precision and positive and negative likelihood ratio of 99%, 78%, 82%, 4.5, 0.013 for Berntson’s method and 55%, 98%, 96%, 27.5, 0.460 for Clifford’s method, respectively. A novel algorithm using a patient-independent threshold derived from the distribution of adRRI values in ICU ECG data identifies artifacts accurately, and outperforms two other methods in common use. Furthermore, the threshold was calculated based on real data from critically ill patients and the algorithm is easy to implement

    Epistasis and genotype-by-environment interaction of grain protein content in durum wheat

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    Parental, F1 , F 2 , BC 1 and BC 2 generations of four crosses involving four cultivars of durum wheat (Triticum durum Desf.) were evaluated at two sites in Tunisia. A three-parameter model was found inadequate for all cases except crosses Chili x Cocorit 71 at site Sidi Thabet and Inrat 69 x Karim at both sites. In most cases a digenic epistatic model was sufficient to explain variation in generation means. Dominance effects (h) and additive x additive epistasis (i) (when significant) were more important than additive (d) effects and other epistatic components. Considering the genotype-by-environment interaction, the non-interactive model (m, d, h, e) was found adequate. Additive variance was higher than environmental variance in three crosses at both sites. The estimated values of narrow-sense heritability were dependent upon the cross and the sites and were 0%-85%. The results indicate that appropriate choice of environment and selection in later generations would increase grain protein content in durum wheat

    A framework for feature extraction from hospital medical data with applications in risk prediction

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    Background: Feature engineering is a time consuming component of predictive modeling. We propose a versatile platform to automatically extract features for risk prediction, based on a pre-defined and extensible entity schema. The extraction is independent of disease type or risk prediction task. We contrast auto-extracted features to baselines generated from the Elixhauser comorbidities. Results: Hospital medical records was transformed to event sequences, to which filters were applied to extract feature sets capturing diversity in temporal scales and data types. The features were evaluated on a readmission prediction task, comparing with baseline feature sets generated from the Elixhauser comorbidities. The prediction model was through logistic regression with elastic net regularization. Predictions horizons of 1, 2, 3, 6, 12 months were considered for four diverse diseases: diabetes, COPD, mental disorders and pneumonia, with derivation and validation cohorts defined on non-overlapping data-collection periods. For unplanned readmissions, auto-extracted feature set using socio-demographic information and medical records, outperformed baselines derived from the socio-demographic information and Elixhauser comorbidities, over 20 settings (5 prediction horizons over 4 diseases). In particular over 30-day prediction, the AUCs are: COPD-baseline: 0.60 (95% CI: 0.57, 0.63), auto-extracted: 0.67 (0.64, 0.70); diabetes-baseline: 0.60 (0.58, 0.63), auto-extracted: 0.67 (0.64, 0.69); mental disorders-baseline: 0.57 (0.54, 0.60), auto-extracted: 0.69 (0.64,0.70); pneumonia-baseline: 0.61 (0.59, 0.63), auto-extracted: 0.70 (0.67, 0.72). Conclusions: The advantages of auto-extracted standard features from complex medical records, in a disease and task agnostic manner were demonstrated. Auto-extracted features have good predictive power over multiple time horizons. Such feature sets have potential to form the foundation of complex automated analytic tasks

    Systemic Signature of the Lung Response to Respiratory Syncytial Virus Infection

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    Respiratory Syncytial Virus is a frequent cause of severe bronchiolitis in children. To improve our understanding of systemic host responses to RSV, we compared BALB/c mouse gene expression responses at day 1, 2, and 5 during primary RSV infection in lung, bronchial lymph nodes, and blood. We identified a set of 53 interferon-associated and innate immunity genes that give correlated responses in all three murine tissues. Additionally, we identified blood gene signatures that are indicative of acute infection, secondary immune response, and vaccine-enhanced disease, respectively. Eosinophil-associated ribonucleases were characteristic for the vaccine-enhanced disease blood signature. These results indicate that it may be possible to distinguish protective and unfavorable patient lung responses via blood diagnostics

    The Anti-interferon Activity of Conserved Viral dUTPase ORF54 is Essential for an Effective MHV-68 Infection

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    Gammaherpesviruses such as KSHV and EBV establish lifelong persistent infections through latency in lymphocytes. These viruses have evolved several strategies to counteract the various components of the innate and adaptive immune systems. We conducted an unbiased screen using the genetically and biologically related virus, MHV-68, to find viral ORFs involved in the inhibition of type I interferon signaling and identified a conserved viral dUTPase, ORF54. Here we define the contribution of ORF54 in type I interferon inhibition by ectopic expression and through the use of genetically modified MHV-68. ORF54 and an ORF54 lacking dUTPase enzymatic activity efficiently inhibit type I interferon signaling by inducing the degradation of the type I interferon receptor protein IFNAR1. Subsequently, we show in vitro that the lack of ORF54 causes a reduction in lytic replication in the presence of type I interferon signaling. Investigation of the physiological consequence of IFNAR1 degradation and importance of ORF54 during MHV-68 in vivo infection demonstrates that ORF54 has an even greater impact on persistent infection than on lytic replication. MHV-68 lacking ORF54 expression is unable to efficiently establish latent infection in lymphocytes, although it replicates relatively normally in lung tissues. However, infection of IFNAR−/− mice alleviates this phenotype, emphasizing the specific role of ORF54 in type I interferon inhibition. Infection of mice and cells by a recombinant MHV-68 virus harboring a site specific mutation in ORF54 rendering the dUTPase inactive demonstrates that dUTPase enzymatic activity is not required for anti-interferon function of ORF54. Moreover, we find that dUTPase activity is dispensable at all stages of MHV-68 infection analyzed. Overall, our data suggest that ORF54 has evolved anti-interferon activity in addition to its dUTPase enzymatic activity, and that it is actually the anti-interferon role that renders ORF54 critical for establishing an effective persistent infection of MHV-68

    Serum MicroRNAs as Biomarkers for Hepatocellular Carcinoma in Chinese Patients with Chronic Hepatitis B Virus Infection

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    BACKGROUND: MicroRNAs (miRNAs) have been shown to anticipate great cancer diagnostic potential. Recently, circulating miRNAs have been reported as promising biomarkers for various pathologic conditions. The objective of this study was to investigate the potential of serum miRNAs as novel biomarkers for hepatocellular carcinoma (HCC). METHODOLOGY/PRINCIPAL FINDINGS: This study was divided into four phases: (I) Ten candidate serum miRNAs were detected by using real-time RT-PCR, corresponding 10 HCC patients with chronic hepatitis B virus (HBV) infection and 10 age- and sex-matched healthy subjects. (II) Marker validation by real-time RT-PCR on HBV patients with (n = 48) or without HCC (n = 48), and healthy subjects (n = 24). (III) Marker detection by real-time RT-PCR in sera from another 14 HCC patients before and 1 month after surgical resection. (IV) We examined the correlation between the expressions of candidate serum miRNAs with clinical parameters of HCC patients. Although miR-222, miR-223 or miR-21 were significantly up- or down-regulated between HCC patients and healthy controls, no significant difference was observed in the levels of these miRNAs between HBV patients without and with HCC. MiR-122 in serum was significantly higher in HCC patients than healthy controls (p<0.001). More importantly, it was found that the levels of miR-122 were significantly reduced in the post-operative serum samples when compared to the pre-operative samples. Although serum miR-122 was also elevated in HBV patients with HCC comparing with those without HCC, the difference was at the border line (p = 0.043). CONCLUSIONS/SIGNIFICANCE: Our results suggest that serum miR-122 might serve as a novel and potential noninvasive biomarker for detection of HCC in healthy subjects, moreover, it might serve as a novel biomarker for liver injury but not specifically for detection of HCC in chronic HBV infection patients

    HIV-1 Promotes Renal Tubular Epithelial Cell Protein Synthesis: Role of mTOR Pathway

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    Tubular cell HIV-infection has been reported to manifest in the form of cellular hypertrophy and apoptosis. In the present study, we evaluated the role of mammalian target of rapamycin (mTOR) pathway in the HIV induction of tubular cell protein synthesis. Mouse proximal tubular epithelial cells (MPTECs) were transduced with either gag/pol-deleted NL4-3 (HIV/MPTEC) or empty vector (Vector/MPTEC). HIV/MPTEC showed enhanced DNA synthesis when compared with Vector/MPTECs by BRDU labeling studies. HIV/MPTECs also showed enhanced production of β-laminin and fibronection in addition to increased protein content per cell. In in vivo studies, renal cortical sections from HIV transgenic mice and HIVAN patients showed enhanced tubular cell phosphorylation of mTOR. Analysis of mTOR revealed increased expression of phospho (p)-mTOR in HIV/MPTECs when compared to vector/MPTECs. Further downstream analysis of mTOR pathway revealed enhanced phosphorylation of p70S6 kinase and associated diminished phosphorylation of eEF2 (eukaryotic translation elongation factor 2) in HIV/MPTECs; moreover, HIV/MPTECs displayed enhanced phosphorylation of eIF4B (eukaryotic translation initiation factor 4B) and 4EBP-1 (eukaryotic 4E binding protein). To confirm our hypothesis, we evaluated the effect of rapamycin on HIV-induced tubular cell downstream signaling. Rapamycin not only attenuated phosphorylation of p70S6 kinase and associated down stream signaling in HIV/MPTECs but also inhibited HIV-1 induced tubular cell protein synthesis. These findings suggest that mTOR pathway is activated in HIV-induced enhanced tubular cell protein synthesis and contributes to tubular cell hypertrophy
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