190 research outputs found

    Assessment of Resilience in Desalination Infrastructure Using Semi-Markov Models

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    As the supply of desalinated water becomes significant in many countries, the reliable long-term operation of desalination infrastructure becomes paramount. As it is not realistic to build desalination systems with components that never fail, instead the system should be designed with more resilience. To answer the question how resilient the system should be, we present in this paper a quantitative approach to measure system resilience using semi-Markov models. This approach allows to probabilistically represent the resilience of a desalination system, considering the functional or failed states of its components, as well as the probability of failure and repair rates. As the desalination plants are connected with the end-user through water transportation and distribution networks, this approach also enables an evaluation of various network configurations and resilience strategies. A case study addressing a segment of the water system in Saudi Arabia is given with the results, benefits, and limitations of the technique discussed.Center for Complex Engineering Systems at MIT and KACSTUnited States. National Aeronautics and Space Administration (Space Technology Research Fellowship, grant number NNX14AM42H

    Studies on two polyherbal formulations (ZPTO and ZTO) for comparison of their antidyslipidemic, antihypertensive and endothelial modulating activities

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    Background Cardiovascular disorders (CVDs) are the leading cause of disease burden worldwide. Apart from available synthetic drugs used in CVDs, there are many herbal formulations including POL-10 (containing 10 herbs), which have been shown to be effective in animal studies but POL-10 was found to cause tachycardia in rodents as its side effect. This study was designed to modify the composition of POL-10 for better efficacy and/or safety profile in CVDs. Methods To assess the antidyslipidemic, antihypertensive and endothelial modulatory properties of two herbal formulations, (ZPTO and ZTO) containing Z: Zingiber officinalis, P: Piper nigrum, T: Terminalia belerica and O: Orchis mascula, different animal models including, tyloxapol and high fat diet-induced dyslipidemia and spontaneously hypertensive rats (SHR) were used. Effect on endothelial function was studied using isolated tissue bath set up coupled with PowerLab data acquisition system. The antioxidant activity was carried out using DPPH radical-scavenging assay. Results Based on preliminary screening of the ingredients of POL-10 in tyloxapol-induced hyperlipidemic rats, ZPTO and ZTO containing four active ingredients namely; Z, P, T and O were identified for further studies and comparison. In tyloxapol-induced hyperlipidemic rats, both ZPTO and ZTO caused significant reduction in serum triglyceride (TG) and total cholesterol (TC). In high fat diet-fed rats, ZPTO decreased TC, low-density lipoproteins cholesterol (LDL-C) and atherogenic index (AI). ZTO also showed similar effects to those of ZPTO with additional merits being more effective in reducing AI, body weight and more importantly raising high-density lipoproteins. In SHR, both formulations markedly reduced systolic blood pressure, AI and TG levels, ZTO being more potent in reversing endothelial dysfunction while was devoid of cardiac stimulatory effect. In addition, ZTO also reduced LDL-C and improved glucose levels in SHR. In DPPH radical-scavenging activity test, ZTO was also more potent than ZPTO. Conclusion The modified formulation, ZTO was not only found more effective in correcting cardiovascular abnormalities than ZPTO or POL-10 but also it was free from tachycardiac side-effect, which might be observed because of the presence of Piper nigrum in ZPTO

    Species and tissue-specificity of prokinetic, laxative and spasmodic effects of Fumaria parviflora

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    <p>Abstract</p> <p>Background</p> <p><it>Fumaria parviflora </it>Linn. (<it>Fumariaceae</it>), is a small branched annual herb found in many parts of the world including Saudi Arabia and Pakistan. This study was designed to provide pharmacological basis for the medicinal use of <it>Fumaria parviflora </it>in gut motility disorders.</p> <p>Methods</p> <p>The <it>in-vivo </it>prokinetic and laxative assays were conducted in mice. Isolated intestinal preparations (ileum and jejunum) from different animal species (mouse, guinea-pig and rabbit) were separately suspended in tissue baths containing Tyrode's solution bubbled with carbogen and maintained at 37°C. The spasmogenic responses were recorded using isotonic transducers coupled with PowerLab data acquisition system.</p> <p>Results</p> <p>The aqueous-methanol extract of <it>Fumaria parviflora </it>(Fp.Cr), which tested positive for the presence of alkaloids, saponins, tannins and anthraquinones showed partially atropine-sensitive prokinetic and laxative activities in the <it>in-vivo </it>in mice at 30 and 100 mg/kg. In the <it>in-vitro </it>studies, Fp.Cr (0.01-1 mg/ml) caused a concentration-dependent atropine-sensitive stimulatory effect both in mouse tissues (jejunum and ileum), and rabbit jejunum but had no effect in rabbit ileum. In guinea-pig tissues (ileum and jejunum), the crude extract showed a concentration-dependent stimulatory effect with higher efficacy in ileum and the effect was partially blocked by atropine, indicating the involvement of more than one types of gut-stimulant components (atropine-sensitive and insensitive). This could be a plausible reason for the greater efficacy of Fp.Cr in gut preparations of guinea-pig than in rabbit or mouse.</p> <p>Conclusions</p> <p>This study shows the prokinetic, laxative and spasmodic effects of the plant extract partially mediated through cholinergic pathways with species and tissue-selectivity, and provides a sound rationale for the medicinal use of <it>Fumaria parviflora </it>in gut motility disorders such as, indigestion and constipation. This study also suggests using different species to know better picture of pharmacological profile of the test material.</p

    The association of RANTES polymorphism with severe acute respiratory syndrome in Hong Kong and Beijing Chinese

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    <p>Abstract</p> <p>Background</p> <p>Chemokines play important roles in inflammation and antiviral action. We examined whether polymorphisms of <it>RANTES, IP-10 </it>and <it>Mig </it>affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS).</p> <p>Methods</p> <p>We tested the polymorphisms of <it>RANTES, IP-10 </it>and <it>Mig </it>for their associations with SARS in 495 Hong Kong Chinese SARS patients and 578 controls. Then we tried to confirm the results in 356 Beijing Chinese SARS patients and 367 controls.</p> <p>Results</p> <p><it>RANTES </it>-28 G allele was associated with SARS susceptibility in Hong Kong Chinese (<it>P </it>< 0.0001, OR = 2.80, 95%CI:2.11–3.71). Individuals with <it>RANTES </it>-28 CG and GG genotypes had a 3.28-fold (95%CI:2.32–4.64) and 3.06-fold (95%CI:1.47–6.39) increased risk of developing SARS respectively (<it>P </it>< 0.0001). This -28 G allele conferred risk of death in a gene-dosage dependent manner (<it>P </it>= 0.014) with CG and GG individuals having a 2.12-fold (95% CI: 1.11–4.06) and 4.01-fold (95% CI: 1.30–12.4) increased risk. For the replication of <it>RANTES </it>data in Beijing Chinese, the -28 G allele was not associated with susceptibility to SARS. However, -28 CG (OR = 4.27, 95%CI:1.64–11.1) and GG (OR = 3.34, 95%CI:0.37–30.7) were associated with admission to intensive care units or death due to SARS (<it>P </it>= 0.011).</p> <p>Conclusion</p> <p><it>RANTES </it>-28 G allele plays a role in the pathogenesis of SARS.</p

    The interferon gamma gene polymorphism +874 A/T is associated with severe acute respiratory syndrome

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    BACKGROUND: Cytokines play important roles in antiviral action. We examined whether polymorphisms of IFN-γ,TNF-α and IL-10 affect the susceptibility to and outcome of severe acute respiratory syndrome (SARS). METHODS: A case-control study was carried out in 476 Chinese SARS patients and 449 healthy controls. We tested the polymorphisms of IFN-γ,TNF-α and IL-10 for their associations with SARS. RESULTS: IFN-γ +874A allele was associated with susceptibility to SARS in a dose-dependent manner (P < 0.001). Individuals with IFN-γ +874 AA and AT genotype had a 5.19-fold (95% Confidence Interval [CI], 2.78-9.68) and 2.57-fold (95% CI, 1.35-4.88) increased risk of developing SARS respectively. The polymorphisms of IL-10 and TNF-α were not associated with SARS susceptibility. CONCLUSION: IFN-γ +874A allele was shown to be a risk factor in SARS susceptibility

    IQ and the Weight of Nations

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    The antecedents of the ‘weights of nations’ have been in the center of theoretical and empirical discussion over the past decades. In this research, we contribute to extant studies by investigating the effect of general intelligence, measured by nation IQ, on the Body Mass Indices (BMI) of male and female populations for 187 countries of the world. Our results suggest an inverted U-shaped link between intelligence and BMI. Even after controlling for an alternative set of control variables such as trade openness, urbanization and others, our results remain intact. This paper documents a turning point of 80.8 for female and 83.7 IQ score for male BMI. The results remain robust to a number of robustness checks

    Why Functional Pre-Erythrocytic and Bloodstage Malaria Vaccines Fail: A Meta-Analysis of Fully Protective Immunizations and Novel Immunological Model

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    Background: Clinically protective malaria vaccines consistently fail to protect adults and children in endemic settings, and at best only partially protect infants. Methodology/Principal Findings: We identify and evaluate 1916 immunization studies between 1965-February 2010, and exclude partially or nonprotective results to find 177 completely protective immunization experiments. Detailed reexamination reveals an unexpectedly mundane basis for selective vaccine failure: live malaria parasites in the skin inhibit vaccine function. We next show published molecular and cellular data support a testable, novel model where parasite-host interactions in the skin induce malaria-specific regulatory T cells, and subvert early antigen-specific immunity to parasite-specific immunotolerance. This ensures infection and tolerance to reinfection. Exposure to Plasmodium-infected mosquito bites therefore systematically triggers immunosuppression of endemic vaccine-elicited responses. The extensive vaccine trial data solidly substantiate this model experimentally. Conclusions/Significance: We conclude skinstage-initiated immunosuppression, unassociated with bloodstage parasites, systematically blocks vaccine function in the field. Our model exposes novel molecular and procedural strategies to significantly and quickly increase protective efficacy in both pipeline and currently ineffective malaria vaccines, and forces fundamental reassessment of central precepts determining vaccine development. This has major implications fo
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