30 research outputs found

    Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

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    In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The powersupply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to theindispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer needconsidering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, butalso parasitic capacitance resulted from the insulation wrappings on the high-voltage side. This research exhibits asimple approach to measuring equivalent circuit parameters of the high-frequency, high-voltage transformer with straycapacitance being introduced into the conventional modeling. The proposed modeling scheme provides not only aprecise measurement procedure but also effective design information for series-load resonant converter. The plasmadischarging plate is designed as part of the electric circuit in the series load-resonant converter and the circuit modelof the plasma discharging plate is also conducted as well. Thus, the overall model of the high-voltage plasmagenerator is built and the designing procedures for appropriate selections of the corresponding resonant-circuitparameters can be established. Finally, a high-voltage plasma generator with 220V, 60Hz, and 1kW input, along witha 22 kHz and over 8kV output, is realized and implemented

    Efficacy of Single-Dose and Triple-Dose Albendazole and Mebendazole against Soil-Transmitted Helminths and Taenia spp.: A Randomized Controlled Trial

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    BACKGROUND: The control of soil-transmitted helminth (STH) infections currently relies on the large-scale administration of single-dose oral albendazole or mebendazole. However, these treatment regimens have limited efficacy against hookworm and Trichuris trichiura in terms of cure rates (CR), whereas fecal egg reduction rates (ERR) are generally high for all common STH species. We compared the efficacy of single-dose versus triple-dose treatment against hookworm and other STHs in a community-based randomized controlled trial in the People's Republic of China. METHODOLOGY/PRINCIPAL FINDINGS: The hookworm CR and fecal ERR were assessed in 314 individuals aged </=5 years who submitted two stool samples before and 3-4 weeks after administration of single-dose oral albendazole (400 mg) or mebendazole (500 mg) or triple-dose albendazole (3x400 mg over 3 consecutive days) or mebendazole (3x500 mg over 3 consecutive days). Efficacy against T. trichiura, Ascaris lumbricoides, and Taenia spp. was also assessed. ALBENDAZOLE CURED SIGNIFICANTLY MORE HOOKWORM INFECTIONS THAN MEBENDAZOLE IN BOTH TREATMENT REGIMENS (SINGLE DOSE: respective CRs 69% (95% confidence interval [CI]: 55-81%) and 29% (95% CI: 20-45%); triple dose: respective CRs 92% (95% CI: 81-98%) and 54% (95% CI: 46-71%)). ERRs followed the same pattern (single dose: 97% versus 84%; triple dose: 99.7% versus 96%). Triple-dose regimens outperformed single doses against T. trichiura; three doses of mebendazole - the most efficacious treatment tested - cured 71% (95% CI: 57-82%). Both single and triple doses of either drug were highly efficacious against A. lumbricoides (CR: 93-97%; ERR: all <99.9%). Triple dose regimens cured all Taenia spp. infections, whereas single dose applications cured only half of them. CONCLUSIONS/SIGNIFICANCE: Single-dose oral albendazole is more efficacious against hookworm than mebendazole. To achieve high CRs against both hookworm and T. trichiura, triple-dose regimens are warranted. CONCLUSIONS/SIGNIFICANCE: Single-dose oral albendazole is more efficacious against hookworm than mebendazole. To achieve high CRs against both hookworm and T. trichiura, triple-dose regimens are warranted. TRIAL REGISTRATION: www.controlled-trials.comISRCTN4737502

    Tribendimidine and Albendazole for Treating Soil-Transmitted Helminths, Strongyloides stercoralis and Taenia spp.: Open-Label Randomized Trial

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    More than a billion people are infected with intestinal worms and, in the developing world, many individuals harbor several kinds of worms concurrently. There are only a handful of drugs available for treatment, and drug efficacy varies according to the worm species. We compared the efficacy of a single oral dose of tribendimidine, a new broad-spectrum worm drug from China, with the standard drug albendazole for the treatment of hookworm, large roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura) and, for the first time, Strongyloides stercoralis and tapeworm (Taenia spp.). Our single-blind randomized trial was conducted in a village in Yunnan province, southwest China. Both drugs showed high efficacy against A. lumbricoides and a moderate efficacy against hookworm. Among 57 tribendimidine recipients, the prevalence of S. stercoralis was reduced from 19.3% to 8.8%, and that of Taenia spp. from 26.3% to 8.8%. Similar prevalence reductions were noted among the 66 albendazole recipients. Taking into account additional infections only discovered at treatment evaluation, the difference between the drug-specific Taenia spp. net cure rates was highly significant in favor of tribendimidine. In view of our promising results, multiple-dose schedules with tribendimidine against S. stercoralis and Taenia spp. should be evaluated next

    Human Angiostrongyliasis Outbreak in Dali, China

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    Angiostrongyliasis, caused by the rat lungworm Angiostrongylus cantonensis, is a potentially fatal food-borne disease. It is endemic in parts of Southeast Asia, the Pacific Islands, Australia, and the Caribbean. Outbreaks have become increasingly common in China due to the spread of efficient intermediate host snails, most notably Pomacea canaliculata. However, infections are difficult to detect since the disease has a rather long incubation period and few diagnostic clinical symptoms. Reliable diagnostic tests are not widely available. The described angiostrongyliasis epidemic in Dali, China lasted for eight months. Only 11 of a total of 33 suspected patients were clinically confirmed based on a set of diagnostic criteria. Our results demonstrate that the rapid and correct diagnosis of the index patient is crucial to adequately respond to an epidemic, and a set of standardized diagnostic procedures is needed to guide clinicians. Integrated control and management measures including health education, clinical guidelines and a hospital-based surveillance system, should be implemented in areas where snails are a popular food item

    Global, regional, and national incidence and mortality for HIV, tuberculosis, and malaria during 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

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    BACKGROUND: The Millennium Declaration in 2000 brought special global attention to HIV, tuberculosis, and malaria through the formulation of Millennium Development Goal (MDG) 6. The Global Burden of Disease 2013 study provides a consistent and comprehensive approach to disease estimation for between 1990 and 2013, and an opportunity to assess whether accelerated progress has occured since the Millennium Declaration. METHODS: To estimate incidence and mortality for HIV, we used the UNAIDS Spectrum model appropriately modified based on a systematic review of available studies of mortality with and without antiretroviral therapy (ART). For concentrated epidemics, we calibrated Spectrum models to fit vital registration data corrected for misclassification of HIV deaths. In generalised epidemics, we minimised a loss function to select epidemic curves most consistent with prevalence data and demographic data for all-cause mortality. We analysed counterfactual scenarios for HIV to assess years of life saved through prevention of mother-to-child transmission (PMTCT) and ART. For tuberculosis, we analysed vital registration and verbal autopsy data to estimate mortality using cause of death ensemble modelling. We analysed data for corrected case-notifications, expert opinions on the case-detection rate, prevalence surveys, and estimated cause-specific mortality using Bayesian meta-regression to generate consistent trends in all parameters. We analysed malaria mortality and incidence using an updated cause of death database, a systematic analysis of verbal autopsy validation studies for malaria, and recent studies (2010-13) of incidence, drug resistance, and coverage of insecticide-treated bednets. FINDINGS: Globally in 2013, there were 1·8 million new HIV infections (95% uncertainty interval 1·7 million to 2·1 million), 29·2 million prevalent HIV cases (28·1 to 31·7), and 1·3 million HIV deaths (1·3 to 1·5). At the peak of the epidemic in 2005, HIV caused 1·7 million deaths (1·6 million to 1·9 million). Concentrated epidemics in Latin America and eastern Europe are substantially smaller than previously estimated. Through interventions including PMTCT and ART, 19·1 million life-years (16·6 million to 21·5 million) have been saved, 70·3% (65·4 to 76·1) in developing countries. From 2000 to 2011, the ratio of development assistance for health for HIV to years of life saved through intervention was US$4498 in developing countries. Including in HIV-positive individuals, all-form tuberculosis incidence was 7·5 million (7·4 million to 7·7 million), prevalence was 11·9 million (11·6 million to 12·2 million), and number of deaths was 1·4 million (1·3 million to 1·5 million) in 2013. In the same year and in only individuals who were HIV-negative, all-form tuberculosis incidence was 7·1 million (6·9 million to 7·3 million), prevalence was 11·2 million (10·8 million to 11·6 million), and number of deaths was 1·3 million (1·2 million to 1·4 million). Annualised rates of change (ARC) for incidence, prevalence, and death became negative after 2000. Tuberculosis in HIV-negative individuals disproportionately occurs in men and boys (versus women and girls); 64·0% of cases (63·6 to 64·3) and 64·7% of deaths (60·8 to 70·3). Globally, malaria cases and deaths grew rapidly from 1990 reaching a peak of 232 million cases (143 million to 387 million) in 2003 and 1·2 million deaths (1·1 million to 1·4 million) in 2004. Since 2004, child deaths from malaria in sub-Saharan Africa have decreased by 31·5% (15·7 to 44·1). Outside of Africa, malaria mortality has been steadily decreasing since 1990. INTERPRETATION: Our estimates of the number of people living with HIV are 18·7% smaller than UNAIDS's estimates in 2012. The number of people living with malaria is larger than estimated by WHO. The number of people living with HIV, tuberculosis, or malaria have all decreased since 2000. At the global level, upward trends for malaria and HIV deaths have been reversed and declines in tuberculosis deaths have accelerated. 101 countries (74 of which are developing) still have increasing HIV incidence. Substantial progress since the Millennium Declaration is an encouraging sign of the effect of global action. FUNDING: Bill & Melinda Gates Foundation

    Discovery and Characterization of the Tuberculosis Drug Lead Ecumicin

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    The new tuberculosis (TB) lead ecumicin (<b>1</b>), a cyclic tridecapeptide, was isolated from <i>Nonomuraea sp.</i> MJM5123, following a high-throughput campaign for anti-TB activity. The large molecular weight of 1599 amu detected by LC-HR-MS precluded the initial inference of its molecular formula. The individual building blocks were identified by extensive NMR experiments. The resulting two possible planar structures were distinguished by LC-MS<sup>2</sup>. Determination of absolute configuration and unambiguous structural confirmation were carried out by X-ray crystallography and Marfey’s analysis
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