This paper presents the comparative study of the mechanical properties of Al6061-Tungsten carbide composites containing Tungsten carbide (WC) particulate, and Al6061-graphite particulate composites containing graphite...This paper presents the comparative study of the mechanical properties of Al6061-Tungsten carbide composites containing Tungsten carbide (WC) particulate, and Al6061-graphite particulate composites containing graphite particles. The reinforcing particulates in the MMCs vary from 0% to 4% by weight. The 'vortex method' of production was employed to fabricate the composites, in which the reinforcements were poured into the vortex created by stirring the molten metal by means of a mechanical agitator. The composites so produced were subjected to a series of tests. The results of this study revealed that as the Tungsten carbide particle content was increased, there were significant increases in the ultimate tensile strength, hardness and Young's modulus, accompanied by a reduction in its ductility. There was, however, only a very marginal increase in the compressive strength, where as in graphite reinforced composites as the graphite content was increased, there were significant reduction in hardness and monotonic increases in the ductility, ultimate tensile strength (UTS), compressive strength and Young's modulus of the composite, An attempt is made in the paper to provide explanations for these phenomena.展开更多
Nowadays, more than ever, the improvement of access to family planning (FP) has become an international goal. What constitutes access to FP? Current human rights-based contraceptive guidelines indicate that access beg...Nowadays, more than ever, the improvement of access to family planning (FP) has become an international goal. What constitutes access to FP? Current human rights-based contraceptive guidelines indicate that access begins as soon as women or couples express a desire to avoid pregnancy and their risk of unintended pregnancy is established. However, few studies have sought to define and measure cognitive and psychosocial access to contraception. To propose a comprehensive framework for the cognitive and psychosocial accessibility of contraception, we critically analyzed the literature on attitudes toward FP. The main dimensions that emerged were knowledge about FP, fear of side effects, approval of contraception, and contraceptive agency. We then identified and adjusted some questions that can capture these dimensions more comprehensively. As a result, we developed a questionnaire module comprising 15 questions, which was integrated into the 6th round of the PMA2020 survey in Burkina Faso in 2019. This research highlighted that previous studies have collected separate dimensions of contraceptive access, and the psychosocial dimension tended to be neglected. Our results demonstrate that it is possible to collect comprehensive data on cognitive and psychosocial dimensions of access to family planning.展开更多
BACKGROUND In 2019,the Nigerian Ministry of Health published the first operational guidelines for human immunodeficiency virus self-testing(HIVST)to improve access to human immunodeficiency virus(HIV)testing services ...BACKGROUND In 2019,the Nigerian Ministry of Health published the first operational guidelines for human immunodeficiency virus self-testing(HIVST)to improve access to human immunodeficiency virus(HIV)testing services among undertested populations in the country.Also,as part of the campaign to increase HIV testing services in Nigeria,the Nigerian Ministry of Health developed standard operating procedures for using HIVST kits.AIM To systematically review the acceptability and strategies for enhancing the uptake of HIVST in Nigeria.METHODS The systematic review was conducted and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.Different databases were searched to get the necessary materials needed for this review.Standardized forms developed by the authors were used for data extraction to minimize the risk of bias and ensure that the articles used for the study were properly screened.Identified articles were first screened using the titles and their abstracts.The full papers were screened,and the similarities of the documents were determined.Qualitative,quantitative,and mixed-method studies were evaluated using the Critical Appraisal Skills Programme and Critical Appraisal Framework criteria.RESULTS All the publications reviewed were published between 2015 and 2022,with 33.3%published in 2021.Most(77.8%)of the studies were cross-sectional,43.3%were conducted in Lagos State,and 26.3%were conducted among young people.The study revealed a high level of acceptability of HIVST.Certain factors,such as gender,sexual activity,and previous testing experience,influence the acceptability of HIV self-testing,with some individuals more likely to opt-out.The cost of the kit was reported as the strongest factor for choosing HIVST services,and this ranged from 200 to 4000 Naira(approximately United States Dollar 0.55-11.07),with the majority willing to pay 500 Naira(approximately United States Dollar 1.38).Privately-owned,registered pharmacies,youthfriendly centres,supermarkets,and online stores were the most cited access locations for HIVST.The least influential attribute was the type of specimen needed for HIVST.Strategies addressing cost and preferred access points and diverse needs for social media promotion,local translation of product use instructions,and HIVST distribution led by key opinion leaders for key populations were found to significantly enhance HIVST uptake and linkage to care.CONCLUSION HIVST acceptability is generally high from an intention-to-use perspective.Targeted strategies are required to improve the acceptability of HIV self-testing,especially among males,sexually active individuals,and first-time testers.Identified and proposed uptake-enhancing strategies need to be investigated in controlled settings and among different populations and distribution models in Nigeria.展开更多
Background:Early neurologic deterioration(END)may occur in patients with anterior circulation ischemic stroke(ACIS)after receiving endovascular treatment(EVT).Hemodynamic insufficiency,re-occlusion,and post-re-canaliz...Background:Early neurologic deterioration(END)may occur in patients with anterior circulation ischemic stroke(ACIS)after receiving endovascular treatment(EVT).Hemodynamic insufficiency,re-occlusion,and post-re-canalization hyper-perfusion are likely to play a critical role in END.We hypothesized that hemodynamic changes can predict END in patients with ACIS postsuccessful EVT using trans-cranial Doppler(TCD).Methods:We utilized a prospectively maintained database of ACIS patients treated with EVT between September 2016 and June 2018 in the Xuanwu Hospital,Capital Medical University.TCD parameters including peak systolic velocity(PSV),bilateral mean flow velocity(MFV),and pulse index(PI)were determined via the middle cerebral arteries within 72 h post-EVT.A logistic regression model was applied to detect independent predictors for END.Results:Totally,112 EVT patients were included in this study and 80/112 patients experienced successful re-canalization with<50%residual stenosis,while 17/80(21.3%)patients suffered END,for which vasogenic cerebral edema(11/17)was considered as a leading role and followed by symptomatic intra-cranial hemorrhage(4/17)and ischemia progression(2/17).For the 80 patients,the PSV(median:127 cm/s vs.116 cm/s,P=0.039),the ratio of ipsilateral-MFV/contra-lateral-MFV(iMFV/cMFV)(median:1.29 vs.1.02,P=0.036)and iMFV/mean blood pressure(MBP)(median:0.97 vs.0.79,P=0.008)in END patients were higher than those of non-END.Using the receiver-operating characteristic curve to obtain cut-off values for PSV,PI,iMFV/cMFV,and iMFV/MBP for END,we found that PI≥0.85(odds ratio:11.03,95%confidence interval:1.92–63.46,P=0.007)and iMFV/MBP≥0.84(odds ratio:9.20,95%confidence interval:2.07–40.84,P=0.004)were independent predictors of END in a multivariate logistic regression model,with a sensitivity of 82.4%and 76.5%and a specificity of 42.9%and 66.7%,respectively,and had the positive predictive values of 29.0%and 38.2%,and negative predictive values of 90.0%and 91.3%,with an area under the receiveroperating characteristic curve of 0.57 and 0.71,respectively.Conclusion:TCD examination of EVT patients may be used as a real-time tool to detect END predictors,such as the higher PI and iMFV/MBP,allowing for better post-thrombectomy management in ACIS patients.展开更多
文摘This paper presents the comparative study of the mechanical properties of Al6061-Tungsten carbide composites containing Tungsten carbide (WC) particulate, and Al6061-graphite particulate composites containing graphite particles. The reinforcing particulates in the MMCs vary from 0% to 4% by weight. The 'vortex method' of production was employed to fabricate the composites, in which the reinforcements were poured into the vortex created by stirring the molten metal by means of a mechanical agitator. The composites so produced were subjected to a series of tests. The results of this study revealed that as the Tungsten carbide particle content was increased, there were significant increases in the ultimate tensile strength, hardness and Young's modulus, accompanied by a reduction in its ductility. There was, however, only a very marginal increase in the compressive strength, where as in graphite reinforced composites as the graphite content was increased, there were significant reduction in hardness and monotonic increases in the ductility, ultimate tensile strength (UTS), compressive strength and Young's modulus of the composite, An attempt is made in the paper to provide explanations for these phenomena.
文摘Nowadays, more than ever, the improvement of access to family planning (FP) has become an international goal. What constitutes access to FP? Current human rights-based contraceptive guidelines indicate that access begins as soon as women or couples express a desire to avoid pregnancy and their risk of unintended pregnancy is established. However, few studies have sought to define and measure cognitive and psychosocial access to contraception. To propose a comprehensive framework for the cognitive and psychosocial accessibility of contraception, we critically analyzed the literature on attitudes toward FP. The main dimensions that emerged were knowledge about FP, fear of side effects, approval of contraception, and contraceptive agency. We then identified and adjusted some questions that can capture these dimensions more comprehensively. As a result, we developed a questionnaire module comprising 15 questions, which was integrated into the 6th round of the PMA2020 survey in Burkina Faso in 2019. This research highlighted that previous studies have collected separate dimensions of contraceptive access, and the psychosocial dimension tended to be neglected. Our results demonstrate that it is possible to collect comprehensive data on cognitive and psychosocial dimensions of access to family planning.
文摘BACKGROUND In 2019,the Nigerian Ministry of Health published the first operational guidelines for human immunodeficiency virus self-testing(HIVST)to improve access to human immunodeficiency virus(HIV)testing services among undertested populations in the country.Also,as part of the campaign to increase HIV testing services in Nigeria,the Nigerian Ministry of Health developed standard operating procedures for using HIVST kits.AIM To systematically review the acceptability and strategies for enhancing the uptake of HIVST in Nigeria.METHODS The systematic review was conducted and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.Different databases were searched to get the necessary materials needed for this review.Standardized forms developed by the authors were used for data extraction to minimize the risk of bias and ensure that the articles used for the study were properly screened.Identified articles were first screened using the titles and their abstracts.The full papers were screened,and the similarities of the documents were determined.Qualitative,quantitative,and mixed-method studies were evaluated using the Critical Appraisal Skills Programme and Critical Appraisal Framework criteria.RESULTS All the publications reviewed were published between 2015 and 2022,with 33.3%published in 2021.Most(77.8%)of the studies were cross-sectional,43.3%were conducted in Lagos State,and 26.3%were conducted among young people.The study revealed a high level of acceptability of HIVST.Certain factors,such as gender,sexual activity,and previous testing experience,influence the acceptability of HIV self-testing,with some individuals more likely to opt-out.The cost of the kit was reported as the strongest factor for choosing HIVST services,and this ranged from 200 to 4000 Naira(approximately United States Dollar 0.55-11.07),with the majority willing to pay 500 Naira(approximately United States Dollar 1.38).Privately-owned,registered pharmacies,youthfriendly centres,supermarkets,and online stores were the most cited access locations for HIVST.The least influential attribute was the type of specimen needed for HIVST.Strategies addressing cost and preferred access points and diverse needs for social media promotion,local translation of product use instructions,and HIVST distribution led by key opinion leaders for key populations were found to significantly enhance HIVST uptake and linkage to care.CONCLUSION HIVST acceptability is generally high from an intention-to-use perspective.Targeted strategies are required to improve the acceptability of HIV self-testing,especially among males,sexually active individuals,and first-time testers.Identified and proposed uptake-enhancing strategies need to be investigated in controlled settings and among different populations and distribution models in Nigeria.
文摘Background:Early neurologic deterioration(END)may occur in patients with anterior circulation ischemic stroke(ACIS)after receiving endovascular treatment(EVT).Hemodynamic insufficiency,re-occlusion,and post-re-canalization hyper-perfusion are likely to play a critical role in END.We hypothesized that hemodynamic changes can predict END in patients with ACIS postsuccessful EVT using trans-cranial Doppler(TCD).Methods:We utilized a prospectively maintained database of ACIS patients treated with EVT between September 2016 and June 2018 in the Xuanwu Hospital,Capital Medical University.TCD parameters including peak systolic velocity(PSV),bilateral mean flow velocity(MFV),and pulse index(PI)were determined via the middle cerebral arteries within 72 h post-EVT.A logistic regression model was applied to detect independent predictors for END.Results:Totally,112 EVT patients were included in this study and 80/112 patients experienced successful re-canalization with<50%residual stenosis,while 17/80(21.3%)patients suffered END,for which vasogenic cerebral edema(11/17)was considered as a leading role and followed by symptomatic intra-cranial hemorrhage(4/17)and ischemia progression(2/17).For the 80 patients,the PSV(median:127 cm/s vs.116 cm/s,P=0.039),the ratio of ipsilateral-MFV/contra-lateral-MFV(iMFV/cMFV)(median:1.29 vs.1.02,P=0.036)and iMFV/mean blood pressure(MBP)(median:0.97 vs.0.79,P=0.008)in END patients were higher than those of non-END.Using the receiver-operating characteristic curve to obtain cut-off values for PSV,PI,iMFV/cMFV,and iMFV/MBP for END,we found that PI≥0.85(odds ratio:11.03,95%confidence interval:1.92–63.46,P=0.007)and iMFV/MBP≥0.84(odds ratio:9.20,95%confidence interval:2.07–40.84,P=0.004)were independent predictors of END in a multivariate logistic regression model,with a sensitivity of 82.4%and 76.5%and a specificity of 42.9%and 66.7%,respectively,and had the positive predictive values of 29.0%and 38.2%,and negative predictive values of 90.0%and 91.3%,with an area under the receiveroperating characteristic curve of 0.57 and 0.71,respectively.Conclusion:TCD examination of EVT patients may be used as a real-time tool to detect END predictors,such as the higher PI and iMFV/MBP,allowing for better post-thrombectomy management in ACIS patients.
