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
We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS)for improving the temperature measurement accuracy and engineering applicability.The proposed method is ba...We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS)for improving the temperature measurement accuracy and engineering applicability.The proposed method is based on double-ended demodulation with a reference temperature and dynamic dispersion difference compensation method,which can suppress the effect of local external physics perturbation and intermodal dispersion on temperature demodulation results.Moreover,the system can omit the pre-calibration process by using the reference temperature before the temperature measurement.The experimental results of dispersion compensation indicate that the temperature accuracy optimizes from 5.6°C to 1.2°C,and the temperature uncertainty decreases from 16.8°C to 2.4°C.Moreover,the double-ended configuration can automatically compensate the local external physics perturbation of the sensing fiber,which exhibits a distinctive improvement.展开更多
Safety berms(also called safety bunds or windrows),widely employed in surface mining and quarry operations,are typically designed based on rules of thumb.Despite having been used by the industry for more than half a c...Safety berms(also called safety bunds or windrows),widely employed in surface mining and quarry operations,are typically designed based on rules of thumb.Despite having been used by the industry for more than half a century and accidents happening regularly,their behaviour is still poorly understood.This paper challenges existing practices through a comprehensive investigation combining full-scale experiments and advanced numerical modelling.Focusing on a Volvo A45G articulated dump truck(ADT)and a CAT 773B rigid dump truck(RDT),collision scenarios under various approach conditions and different safety berm geometries and materials are rigorously examined.The calibrated numerical model is used to assess the energy absorption capacity of safety berms with different geometry and to predict a critical velocity for a specific scenario.Back analysis of an actual fatal accident indicated that an ADT adhering to the speed limit could not be stopped by the safety berm designed under current guidelines.The study highlights the importance of considering the entire geometry and the mass and volume of the material used to build the safety berm alongside the speed and approach conditions of the machinery.The findings of the study enable operators to set speed limits based on specific berm geometries or adapt safety berm designs to match speed constraints for specific machinery.This will reduce the risk of fatal accidents and improve haul road safety.展开更多
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.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.61527819 and 61875146)the Research Project by Shanxi Scholarship Council of China(Nos.2016-036 and 2017-052)+2 种基金the Key Science and Technology Research Project Based on Coal of Shanxi Province(No.MQ2014-09)the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxithe Program for Sanjin Scholar
文摘We propose and experimentally demonstrate a novel Raman-based distributed fiber-optics temperature sensor(RDTS)for improving the temperature measurement accuracy and engineering applicability.The proposed method is based on double-ended demodulation with a reference temperature and dynamic dispersion difference compensation method,which can suppress the effect of local external physics perturbation and intermodal dispersion on temperature demodulation results.Moreover,the system can omit the pre-calibration process by using the reference temperature before the temperature measurement.The experimental results of dispersion compensation indicate that the temperature accuracy optimizes from 5.6°C to 1.2°C,and the temperature uncertainty decreases from 16.8°C to 2.4°C.Moreover,the double-ended configuration can automatically compensate the local external physics perturbation of the sensing fiber,which exhibits a distinctive improvement.
基金initiated and financially supported by Stevenson Aggregates and Fulton Hogan.
文摘Safety berms(also called safety bunds or windrows),widely employed in surface mining and quarry operations,are typically designed based on rules of thumb.Despite having been used by the industry for more than half a century and accidents happening regularly,their behaviour is still poorly understood.This paper challenges existing practices through a comprehensive investigation combining full-scale experiments and advanced numerical modelling.Focusing on a Volvo A45G articulated dump truck(ADT)and a CAT 773B rigid dump truck(RDT),collision scenarios under various approach conditions and different safety berm geometries and materials are rigorously examined.The calibrated numerical model is used to assess the energy absorption capacity of safety berms with different geometry and to predict a critical velocity for a specific scenario.Back analysis of an actual fatal accident indicated that an ADT adhering to the speed limit could not be stopped by the safety berm designed under current guidelines.The study highlights the importance of considering the entire geometry and the mass and volume of the material used to build the safety berm alongside the speed and approach conditions of the machinery.The findings of the study enable operators to set speed limits based on specific berm geometries or adapt safety berm designs to match speed constraints for specific machinery.This will reduce the risk of fatal accidents and improve haul road safety.
