为提高目前电力系统次同步振荡参数辨识精度,提出一种基于随机减量技术RDT(random decrement technique)和稀疏时域STD(sparse time domain)算法相结合的辨识方法。利用RDT对输入信号进行处理,提取自由衰减时域信号。然后通过STD算法计...为提高目前电力系统次同步振荡参数辨识精度,提出一种基于随机减量技术RDT(random decrement technique)和稀疏时域STD(sparse time domain)算法相结合的辨识方法。利用RDT对输入信号进行处理,提取自由衰减时域信号。然后通过STD算法计算得到振荡模态参数。仿真算例和实测算例的结果表明,该方法可以有效地辨识出次同步振荡的模态参数,可以用于辨识电力系统次同步振荡,为抑制次同步振荡的设计奠定了基础。展开更多
A total of 415 samples from febrile children exhibiting either concordant (n = 108) or discordant (n = 307) results between microscopy, the gold standard diagnostic test, and two Rapid Diagnostic Tests (RDTs), OptiMAL...A total of 415 samples from febrile children exhibiting either concordant (n = 108) or discordant (n = 307) results between microscopy, the gold standard diagnostic test, and two Rapid Diagnostic Tests (RDTs), OptiMAL-IT?(pLDH) and Acon?HRP2, were analysed using polymerase chain reaction (PCR) from May to December 2011 in Gabon. The aim of the study was to analyse these discrepancies using poly-merase chain reaction (PCR). Nested PCR targeting the Plasmodium ssrRNA gene was used to distinguish P. falciparum, P. malariae and P. ovale. Plasmodium falciparum was the only malaria species identified. Discrepancies frequently involved samples that were negative by microscopy and positive by Acon?HRP2 (90%) or Optimal-it?(86%). The PCR assay detected submicroscopic infection in almost 23% of the microscopy-negative samples, whereas plasmodial DNA was not found in 77% of the Acon?HRP2 positive-microscopy negative samples. Although results obtained with Optimal-it? were more frequently concordant with those of PCR genotyping, the low specificity of Optimal-iT?for non-falciparum malaria parasite detection resulted in a high proportion of false negative RDTs (90%) and a high frequency of tests with faint line intensity. The present study highlights the specific attributes of the different methods used to identify malaria parasite below the microscopy level of detection. RDT results that were discordant with either microscopy or PCR as the gold standard could represent a challenge for rapid, accurate fever case management in malaria endemic areas. It is necessary to pursue the development of more precise and more sensitive point-of-care diagnostic tools for malaria.展开更多
Background： Malaria is the commonest cause of anemia in pregnancy with severe consequence on the developing fetus. Recent clamor by the WHO for testing before treatment has driven a need to assess the effectiveness o...Background： Malaria is the commonest cause of anemia in pregnancy with severe consequence on the developing fetus. Recent clamor by the WHO for testing before treatment has driven a need to assess the effectiveness of available Rapid Diagnostic Tests （RDTs）. Objective： To determine the reliability of Rapid Diagnostic Tests （RDTs） for malaria among pregnant women booking in Federal Teaching Hospital, Ido-Ekiti, Nigeria. Materials and Methods： A cross-sectional study of 240 pregnant women were recruited at booking over a period of twenty weeks. A semi-structured questionnaire sought information about socio demographic data. Blood samples were taken for malaria and diagnosis was done using RDT and Microscopy. Results： Prevalence of malaria was 22.1% by microscopy and 27.5% by RDT. The sensitivity of RDT was 88.7% and specificity was 89.8%. The positive predictive value （PPV） of RDT was 71.2%, the Negative predictive value （NPV） of RDT was 96.6% and accuracy was 89.6%. The reliability of RDT was good （Kappa statistics = 0.731）. The reliability of RDTs when compared with that of Microscopy was also good （Kappa statistics = 0.722）. Conclusions： RDTs was an effective screening test for malaria among the respondents. Hence, primary care physician should utilize this resource by advocating for its availability.展开更多
Background： HRP2-based Rapid Diagnostic Tests （RDTs） for malaria ensure a rational use of artemisinin-based combination therapy （ACT）. The HRP2 antigen can go through the cerebrospinal fluid （CSF）. Purpose： To...Background： HRP2-based Rapid Diagnostic Tests （RDTs） for malaria ensure a rational use of artemisinin-based combination therapy （ACT）. The HRP2 antigen can go through the cerebrospinal fluid （CSF）. Purpose： To assess the HRP2-based RDT in malaria and detect the HRP2 in CSF. Methods： From November 2006 to May 2007, all patients under 15 years showing clinical symptoms of malaria were included. RDT was performed on the CSF and peripheral blood. Results： Out of the 951 patients included, 131 （13.7%） were confirmed through RDT and 130 （13.6%） through thick blood smear. Sensitivity and specificity stood at 96.96% and 99.71% respectively, for uncomplicated cases and at 100% and 99.13% for severe cases. Tests to detect HRP2 in the CSF of 52 cases were negative. Conclusion： Tests to detect HRP2 in the CSF could make it possible to diagnose severe malaria cases when peripheral parasitemia would be below the detection threshold.展开更多
文摘为提高目前电力系统次同步振荡参数辨识精度,提出一种基于随机减量技术RDT(random decrement technique)和稀疏时域STD(sparse time domain)算法相结合的辨识方法。利用RDT对输入信号进行处理,提取自由衰减时域信号。然后通过STD算法计算得到振荡模态参数。仿真算例和实测算例的结果表明,该方法可以有效地辨识出次同步振荡的模态参数,可以用于辨识电力系统次同步振荡,为抑制次同步振荡的设计奠定了基础。
文摘A total of 415 samples from febrile children exhibiting either concordant (n = 108) or discordant (n = 307) results between microscopy, the gold standard diagnostic test, and two Rapid Diagnostic Tests (RDTs), OptiMAL-IT?(pLDH) and Acon?HRP2, were analysed using polymerase chain reaction (PCR) from May to December 2011 in Gabon. The aim of the study was to analyse these discrepancies using poly-merase chain reaction (PCR). Nested PCR targeting the Plasmodium ssrRNA gene was used to distinguish P. falciparum, P. malariae and P. ovale. Plasmodium falciparum was the only malaria species identified. Discrepancies frequently involved samples that were negative by microscopy and positive by Acon?HRP2 (90%) or Optimal-it?(86%). The PCR assay detected submicroscopic infection in almost 23% of the microscopy-negative samples, whereas plasmodial DNA was not found in 77% of the Acon?HRP2 positive-microscopy negative samples. Although results obtained with Optimal-it? were more frequently concordant with those of PCR genotyping, the low specificity of Optimal-iT?for non-falciparum malaria parasite detection resulted in a high proportion of false negative RDTs (90%) and a high frequency of tests with faint line intensity. The present study highlights the specific attributes of the different methods used to identify malaria parasite below the microscopy level of detection. RDT results that were discordant with either microscopy or PCR as the gold standard could represent a challenge for rapid, accurate fever case management in malaria endemic areas. It is necessary to pursue the development of more precise and more sensitive point-of-care diagnostic tools for malaria.
文摘Background： Malaria is the commonest cause of anemia in pregnancy with severe consequence on the developing fetus. Recent clamor by the WHO for testing before treatment has driven a need to assess the effectiveness of available Rapid Diagnostic Tests （RDTs）. Objective： To determine the reliability of Rapid Diagnostic Tests （RDTs） for malaria among pregnant women booking in Federal Teaching Hospital, Ido-Ekiti, Nigeria. Materials and Methods： A cross-sectional study of 240 pregnant women were recruited at booking over a period of twenty weeks. A semi-structured questionnaire sought information about socio demographic data. Blood samples were taken for malaria and diagnosis was done using RDT and Microscopy. Results： Prevalence of malaria was 22.1% by microscopy and 27.5% by RDT. The sensitivity of RDT was 88.7% and specificity was 89.8%. The positive predictive value （PPV） of RDT was 71.2%, the Negative predictive value （NPV） of RDT was 96.6% and accuracy was 89.6%. The reliability of RDT was good （Kappa statistics = 0.731）. The reliability of RDTs when compared with that of Microscopy was also good （Kappa statistics = 0.722）. Conclusions： RDTs was an effective screening test for malaria among the respondents. Hence, primary care physician should utilize this resource by advocating for its availability.
文摘Background： HRP2-based Rapid Diagnostic Tests （RDTs） for malaria ensure a rational use of artemisinin-based combination therapy （ACT）. The HRP2 antigen can go through the cerebrospinal fluid （CSF）. Purpose： To assess the HRP2-based RDT in malaria and detect the HRP2 in CSF. Methods： From November 2006 to May 2007, all patients under 15 years showing clinical symptoms of malaria were included. RDT was performed on the CSF and peripheral blood. Results： Out of the 951 patients included, 131 （13.7%） were confirmed through RDT and 130 （13.6%） through thick blood smear. Sensitivity and specificity stood at 96.96% and 99.71% respectively, for uncomplicated cases and at 100% and 99.13% for severe cases. Tests to detect HRP2 in the CSF of 52 cases were negative. Conclusion： Tests to detect HRP2 in the CSF could make it possible to diagnose severe malaria cases when peripheral parasitemia would be below the detection threshold.
