Percent free prostatic-specific antigen （%fPSA） has been introduced as a tool to avoid unnecessary biopsies in patients with a serum PSA level of 4.0-10.0 ng ml^-1, however, it remains controversial whether %fPSA is...Percent free prostatic-specific antigen （%fPSA） has been introduced as a tool to avoid unnecessary biopsies in patients with a serum PSA level of 4.0-10.0 ng ml^-1, however, it remains controversial whether %fPSA is effective in PSA range of 10.1-20.0 ng ml^-1 in both Chinese and Western population. In this study, the diagnostic performance of %fPSA and serum PSA in predicting prostate cancer （PCa） and high-grade PCa （HGPCa） was analyzed in a multi-center biopsy cohort of 5915 consecutive Chinese patients who underwent prostate biopsy in 22 hospitals across China from January 1, 2010 to December 31, 2013. The indication for biopsy was PSA〉4.0 ng ml^-1 or/and suspicious digital rectal examination. Total and free serum PSA determinations were performed by three types of electrochemiluminescence immunoassays with recalibration to the World Health Organization standards. The diagnostics accuracy of PSA, %fPSA and %fPSA in combination with PSA （%fPSA ＋ PSA） was determined by the area under the receivers operating characteristic curve （AUC）. %fPSA was more effective than PSA in men aged ≥60 years old. The AUC was 0.584 and 0.635 in men aged ≥60 years old with a PSA of 4.0-10.0 ng ml^-1 and 10.1-20.0 ng ml^-1, respectively. The AUC of %fPSA was superior to that of PSA in predicting HGPCa in patients ≥60 years old in these two PSA range. Our results indicated that %fPSA is both statistically effective and clinical applicable to predict prostate biopsy outcome in Chinese patients aged ≥60 years old with a PSA of 4.0-10.0 ng ml^-1 and 10.1-20.0 ng ml^-1.展开更多
Objective:To test the diagnostic performance of percent free prostate-specific antigen(%fPSA)in predicting any prostate cancer(PCa)and high-grade prostate cancer(HGPCa)in a retrospective multi-center biopsy cohort wit...Objective:To test the diagnostic performance of percent free prostate-specific antigen(%fPSA)in predicting any prostate cancer(PCa)and high-grade prostate cancer(HGPCa)in a retrospective multi-center biopsy cohort with a PSA level of 4.0e10.0 ng/mL in China.Methods:Consecutive patients with a PSA of 4.0-10.0 ng/mL who underwent transrectal ultrasound-guided biopsy were enrolled at 16 Chinese medical centers from January 1st,2010 to December 31st,2013.Total and free serum PSA determinations were performed using three types of electro-chemiluminescence immunoassays recalibrated to the World Health Organization(WHO)standard.The diagnostic accuracy of PSA,%fPSA,and %fPSA in combination with PSA(%fPSA t PSA)was determined using the area under the receiver operating characteristic(ROC)curve(AUC).Results:A total of 2310 consecutive men with PSA levels between 4.0 and 10.0 ng/mL were included,and the detection rate of PCa was 25.1%.The AUC of%fPSA and %fPSA t PSA in predicting any PCa was superior to PSA alone in men aged≥60 years(0.623 vs.0.534,p<0.0001)but not in men aged 40e59 years(0.517 vs.0.518,p=0.939).Similar result was yield in predicting HGPCa.Conclusion:In a clinical setting of Chinese men with 4.0e10.0 ng/mL PSA undergoing initial prostate biopsy,adding %fPSA to PSA can moderately improve the diagnostic accuracy for any PCa and HGPCa compared with PSA alone in patients≥60 but not in patients aged 40-59 years.展开更多
Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They ar...Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They are developed from a combination of structural elements and described herein as conventional systems.Among the promising techniques is that redirect the waves propagation through hollow tubes.The blast wave propagation through tubes provides an efficient system since it combines many blast wave phenomena,such as reflection,diffraction,and interaction.In this research,a novel blast load mitigation system,employed as a protection fence,is developed using a technique similar to the technique of the bent tube in manipulating the shock-wave.The relative performance of the novel system to the conventional system is evaluated based on mitigation percent criteria.Performances of both systems are calculated through numerical simulation.The proposed novel system proved to satisfy high performance in mitigating the generated blast waves from charges weight up to 500 kg TNT at relatively small standoff distances(5 m and 8 m).It mitigates at least 94%of the blast waves,which means that only 6%of that blast impulse is considered as the applied load on the targeted structure.展开更多
Percent elongation of ductile metal in uniaxial tension due to non-homogeneity was analyzed based on gradient-dependent plasticity. Three assumptions are used to get the analytical solution of percent elongation: one ...Percent elongation of ductile metal in uniaxial tension due to non-homogeneity was analyzed based on gradient-dependent plasticity. Three assumptions are used to get the analytical solution of percent elongation: one is static equilibrium condition in axial direction; another is that plastic volumetric strain is zero in necking zone; the other is that the diameter in unloading zone remains constant after strain localization is initiated. The strain gradient term was introduced into the yield function of classical plastic mechanics to obtain the analytical solution of distributed plastic strain. Integrating the plastic strain and considering the influence of necking on plastic elongation, a one-dimensional analytical solution of percent elongation was proposed. The analytical solution shows that the percent elongation is inversely proportional to the gauge length, and the solution is formally similar to earlier empirical formula proposed by Barba. Comparisons of existing experimental results and present analytical solutions for relation between load and total elongation and for relation between percent elongation and gauge length were carried out and the new mechanical model for percent elongation was verified. Moreover, higher ductility, toughness and heterogeneity can cause much larger percentage elongation, which coincides with usual viewpoints.展开更多
Objective To evaluate using prostate specific antigen (PSA) and percent free PSA(fPSA) for the diagnosis of prostate cancer(Pca) and benign prostate hyperplasia(BPH). Methods 315 men with BPH and 55 men with Pca wer...Objective To evaluate using prostate specific antigen (PSA) and percent free PSA(fPSA) for the diagnosis of prostate cancer(Pca) and benign prostate hyperplasia(BPH). Methods 315 men with BPH and 55 men with Pca were randomly chosen, serum fPSA and total PSA were determined by ELISA and then we compared the sensitivity and specificity of PSA and percent fPSA for the diagnosis of Pca. Results While using PSA and percent fPSA for the diagnosis of prostate cancer, the sensitivity was similar (89.8% vs. 94.5%, P> 0.05), but the specificity was significanty different (52.7% vs. 89.8%, P< 0.005). Conclusions Using percent fPSA might decrease false-positive and avoid 37.1% negative biopsies as compared with PSA, it is very valuable for the diagnosis of Pca.展开更多
Microalloyed linepipe steels were first introduced in 1959 at strength levels around 52-60 ksi [1] [2].The steels were generally strengthened by niobium or vanadium used singly.As strengths levels increased to X-70 in...Microalloyed linepipe steels were first introduced in 1959 at strength levels around 52-60 ksi [1] [2].The steels were generally strengthened by niobium or vanadium used singly.As strengths levels increased to X-70 in the early 1970’s niobium and vanadium were used in combination and controlled rolling was introduced on a broad basis.Higher strengths decrease tolerance for impurities and non-metallic inclusions which required improved steelmaking practices.Sulfur,carbon,and nitrogen were reduced and continuous casting was increasingly applied which required improved ladle refining and deoxidation practices.Niobium-molybdenum steels were introduced by IPSCO in 1972 [3] and by Italsider in 1974 [4].Steels with higher niobium contents were also introduced in the early 1970’s but available steelmaking technologies limited the use of optimum niobium to carbon ratios,i.e.those approaching stoichiometry.Nevertheless the steels benefited from the effect of niobium in retarding austenite recrystallization at relatively high rolling temperatures and they developed attractive combinations of strength and toughness in old manufacturing facilities using simple (relaxed) rolling schedules.Fluctuations in the price of molybdenum and vanadium in the past decade and expanded application of API Grade X-80 linepipe,have led to more widespread use of niobium contents up to 0.11 percent,in combination with 0.02-0.03 percent carbon (near stoichiometry) thus maximizing the effects of solute niobium during rolling,in lowering transformation temperature,and thereby reducing reliance on other alloying,often expensive,elements.The history of these developments will be presented and applications of the concept will be summarized.展开更多
The purpose of this study is to evaluate the relationship between %HRmax and %vVO2max at constant efforts made at different intensities. In randomized order, males healthy subjects (Age: 25 ± 7 years, Weight: 70 ...The purpose of this study is to evaluate the relationship between %HRmax and %vVO2max at constant efforts made at different intensities. In randomized order, males healthy subjects (Age: 25 ± 7 years, Weight: 70 ± 11 kg, VO2max: 55 ± 8 ml·kg–1·min–1) were divided into two groups, a trained one with more than 3 training sessions per week (n = 10) a moderately trained one with 3 drives or less per week (n = 15). The difference between the two groups corresponds to a time to exhaustion above and below 40 min at 80% vVO2max. All subjects performed 5 tests with a gradual increase in speed of 1 km·h–1 every 2 min and 4 constant speed tests at 60%, 70%, 80% and 90% VO2max. All test were performed at the same time of day (i.e., 18:00 h). The results of this study showed that eighteen collective regressions including different independent variables were developed to predict %HRmax. The individual equations developed, have r values between 0.974 and 0.993 and Syx, between 1.2 and 1.9 ml·kg–1·min–1, they are more accurate than the collective equations (one equation for all subjects) with r values between 0.81 to 0.89 and Syx, between 4.1 and 5.3 ml·kg–1·min–1. In conclusion, this study has demonstrated that the model of predictions of %HRmax from %vVO2max in triangular tests were not appropriate for rectangular efforts. From the equations developed, we find that the time to exhaustion at 90% vVO2max is the best predictor of level of endurance then the time limit to 80% vVO2max.展开更多
China’s consumer price index (CPI), the main gauge of inflation, rose 4 percent in October from a year earlier, the National Bureau of Statistics said on Tuesday. The figure, compared with 4.6 percent in September, 4...China’s consumer price index (CPI), the main gauge of inflation, rose 4 percent in October from a year earlier, the National Bureau of Statistics said on Tuesday. The figure, compared with 4.6 percent in September, 4.9 percent in August,展开更多
2009 was a disappointing year to export sector. In January to November of 2009, China’s textile and garment exports fell by 11.02percent year on year to US $154.12 billion,
Efficient traffic signal system management plays a pivotal role in reducing traffic conges-tion and improving traffic mobility on urban roads.The applications of the automated traf-fic signal performance measures(ATSP...Efficient traffic signal system management plays a pivotal role in reducing traffic conges-tion and improving traffic mobility on urban roads.The applications of the automated traf-fic signal performance measures(ATSPMs)revolutionize the way of proactively managing and evaluating traffic signal systems through a suite of performance measures.The percent arrival on red(PAoR)is one of the commonly used progression performance measures in the ATSPMs to characterize vehicle arrivals at the intersection.However,the accuracy of PAoR to assess arterial signal coordination is restricted by configuration limitations of advance detectors and remains to be further explored.To address this problem,this research proposes an easy-to-use trajectory-based performance measure,i.e.,arterial through percent arrival on red(ATPAoR),for arterial signal coordination performance eval-uation and presents the general procedures to calculate ATPAoRs from connected vehicle data.A case study is carried out to implement the proposed ATPAoR and investigate the relationship between the ATPAoR and the PAoR.It is found that the combination of the time-space diagram(TSD)and arterial through-vehicle trajectories is effective in the actual arterial signal coordination performance visualization,ATPAoR result interpretation,and potential timing improvement recommendations.The PAoRs are found to be greater than the ATPAoRs in undersaturated conditions,and the PAoRs above 60%are recommended to identify poor arterial signal coordination design.The historical TSD can be utilized to verify the accuracy of PAoR to evaluate the actual arterial signal coordination when vehicle tra-jectory data are unavailable.展开更多
Objective:This study aims to assess the feasibility of evaluating the COVID-19 epidemic trend through monitoring the positive percentage of SARS-CoV-19 RNA in wastewater.Method:The study collected data from January to...Objective:This study aims to assess the feasibility of evaluating the COVID-19 epidemic trend through monitoring the positive percentage of SARS-CoV-19 RNA in wastewater.Method:The study collected data from January to August 2023,including the number of reported cases,the positive ratio of nucleic acid samples in sentinel hospitals,the incidence rate of influenza-like symptoms in students,and the positive ratio of wastewater samples in different counties and districts in Shangrao City.Wastewater samples were obtained through grabbing and laboratory testing was completed within 24 h.The data were then normalized using Z-score normalization and analyzed for lag time and correlation using the xcorr function and Spearman correlation coefficient.Results:A total of 2797 wastewater samples were collected.The wastewater monitoring study,based on sampling point distribution,was divided into two phases.Wuyuan County consistently showed high levels of positive ratio in wastewater samples in both phases,reaching peak values of 91.67%and 100%respectively.The lag time analysis results indicated that the peak positive ratio in all wastewater samples in Shangrao City appeared around 2 weeks later compared to the other three indicators.The correlation analysis revealed a strong linear correlation across all four types of data,with Spearman correlation coefficients ranging from 0.783 to 0.977,all of which were statistically significant.Conclusion:The positive ratio of all wastewater samples in Shangrao City accurately reflected the COVID-19 epidemic trend from January to August 2023.This study confirmed the lag effect of wastewater percent positive and its strong correlation with the reported incidence rate and the positive ratio of nucleic acid samples in sentinel hospitals,supporting the use of wastewater percent positive monitoring as a supplementary tool for infectious disease surveillance in the regions with limited resources.展开更多
目的分析1990—2021年全球内脏利什曼病(visceral leishmaniasis,VL)疾病负担变化,并预测2022—2035年VL疾病负担变化趋势,为全球VL防控提供科学依据。方法基于2021年全球疾病负担研究(Global Burden of Disease Study 2021)数据库,获...目的分析1990—2021年全球内脏利什曼病(visceral leishmaniasis,VL)疾病负担变化,并预测2022—2035年VL疾病负担变化趋势,为全球VL防控提供科学依据。方法基于2021年全球疾病负担研究(Global Burden of Disease Study 2021)数据库,获取全球VL年龄标化发病率、患病率、死亡率和伤残调整寿命年(disability-adjusted life years,DALYs)率及其95%不确定性区间(uncertainty interval,UI),采用平均年度变化百分比(average annual percent change,AAPC)及其95%可信区间(confidence interval,CI)描述1990—2021年全球VL疾病负担变化趋势,并按性别、年龄组、国家、地理区域和社会人口学指数(socio-demographic index,SDI)分层后进行分析。采用贝叶斯年龄-时期-队列(Bayesian age-period-cohort,BAPC)模型预测2022—2035年全球VL疾病负担及其变化趋势,采用平滑样条模型分析VL年龄标化发病率、患病率、死亡率、DALYs率与SDI间的相关性。结果1990—2021年全球VL年龄标化发病率[AAPC=-0.25%,95%CI:(-0.25%,-0.24%)]、患病率[AAPC=-0.06%,95%CI:(-0.06%,-0.06%)]、死亡率[AAPC=-0.25%,95%CI:(-0.25%,-0.24%)]和DALYs率[AAPC=-2.38%,95%CI:(-2.44%,-2.33%)]均呈下降趋势。2021年全球不同地理区域中,热带拉丁美洲地区VL年龄标化发病率[2.55/10万,95%UI:(1.49/10万,4.07/10万)]、患病率[0.64/10万,95%UI:(0.37/10万,1.02/10万)]、死亡率[0.51/10万,95%UI:(0,1.80/10万)]、DALYs率[33.81/10万,95%UI:(0.06/10万,124.09/10万)]均最高;全球男性VL年龄标化发病率[0.57/10万,95%UI:(0.45/10万,0.72/10万)]和患病率[0.14/10万,95%UI:(0.11/10万,0.18/10万)]均高于女性[0.27/10万,95%UI:(0.21/10万,0.33/10万);0.06/10万,95%UI:(0.05/10万,0.08/10万)];各年龄组中,5岁以下儿童VL死亡率[0.24/10万,95%UI:(0.08/10万,0.66/10万)]最高。1990—2021年,全球VL年龄标化发病率(r=-0.483,P<0.001)、患病率(r=-0.483,P<0.001)、死亡率(r=-0.511,P<0.001)和DALYs率(r=-0.514,P<0.001)与SDI水平呈显著负相关。经BAPC模型预测,2022—2035年全球VL疾病负担呈下降趋势,2035年VL年龄标化发病率、患病率、死亡率、DALYs率将分别下降至0.11/10万、0.03/10万、0.02/10万、1.44/10万。结论1990—2021年全球VL疾病负担总体呈下降趋势,但中亚和西部撒哈拉以南非洲地区呈上升趋势;男性VL年龄标化发病率及患病率、5岁以下儿童VL年龄标化死亡率相对较高。预测2022—2035年全球VL疾病负担将持续下降。展开更多
Background While China’s socioeconomic transformation has driven divergent trends in gastrointestinal cancers,comprehensive data on esophageal,gastric,and liver cancer burden remain limited.This study examines the gl...Background While China’s socioeconomic transformation has driven divergent trends in gastrointestinal cancers,comprehensive data on esophageal,gastric,and liver cancer burden remain limited.This study examines the global burden of esophageal,gastric,and liver cancers in 2022 and analyzes the trends of age-standardized incidence and mortality rate(ASRs)in China from 2000 to 2018,thereby providing evidence for the formulation of cancer control strategies.Methods The global burden of esophageal,gastric and liver cancers including the estimated number of cases and deaths and the ASRs for incidence and mortality were from GLOBALCAN 2022 dataset.Data from 22 cancer registries in China were employed for the trend analysis of the ASRs for incidence and mortality of these three cancers.The Joinpoint model was used to compute the average annual percentage change(AAPC)of the incidence and mortality of the three cancers from 2000 to 2018.Results Globally,esophageal,gastric and liver cancers accounted for 11.8%of incident cancer cases and 19.1%of cancer deaths.China bore a disproportionately high burden,representing 43.8%,37.0%,and 42.4%of global esophageal,gastric,and liver cancer cases respectively,and 42.1%,39.4%,and 41.7%of corresponding deaths.However,the ASRs for incidence and mortality for all three cancers declined significantly in China(2000–2018),with absolute case numbers decreasing for gastric and esophageal cancers during 2010–2022.Age-specific analysis revealed most pronounced declines in incidence and mortality in populations under 40 years old,with AAPCs of less than–6.0%for esophageal cancer,around–4.0%for gastric cancer,and approximately–2.0%for liver cancer.Conclusions China has achieved remarkable progress in controlling esophageal,gastric and liver cancers,yet these malignancies remain major public health challenges.Future efforts should intensify existing prevention measures while expanding screening programs,particularly for aging populations.These findings offer valuable insights for regions undergoing similar epidemiological transitions.展开更多
文摘Percent free prostatic-specific antigen （%fPSA） has been introduced as a tool to avoid unnecessary biopsies in patients with a serum PSA level of 4.0-10.0 ng ml^-1, however, it remains controversial whether %fPSA is effective in PSA range of 10.1-20.0 ng ml^-1 in both Chinese and Western population. In this study, the diagnostic performance of %fPSA and serum PSA in predicting prostate cancer （PCa） and high-grade PCa （HGPCa） was analyzed in a multi-center biopsy cohort of 5915 consecutive Chinese patients who underwent prostate biopsy in 22 hospitals across China from January 1, 2010 to December 31, 2013. The indication for biopsy was PSA〉4.0 ng ml^-1 or/and suspicious digital rectal examination. Total and free serum PSA determinations were performed by three types of electrochemiluminescence immunoassays with recalibration to the World Health Organization standards. The diagnostics accuracy of PSA, %fPSA and %fPSA in combination with PSA （%fPSA ＋ PSA） was determined by the area under the receivers operating characteristic curve （AUC）. %fPSA was more effective than PSA in men aged ≥60 years old. The AUC was 0.584 and 0.635 in men aged ≥60 years old with a PSA of 4.0-10.0 ng ml^-1 and 10.1-20.0 ng ml^-1, respectively. The AUC of %fPSA was superior to that of PSA in predicting HGPCa in patients ≥60 years old in these two PSA range. Our results indicated that %fPSA is both statistically effective and clinical applicable to predict prostate biopsy outcome in Chinese patients aged ≥60 years old with a PSA of 4.0-10.0 ng ml^-1 and 10.1-20.0 ng ml^-1.
文摘Objective:To test the diagnostic performance of percent free prostate-specific antigen(%fPSA)in predicting any prostate cancer(PCa)and high-grade prostate cancer(HGPCa)in a retrospective multi-center biopsy cohort with a PSA level of 4.0e10.0 ng/mL in China.Methods:Consecutive patients with a PSA of 4.0-10.0 ng/mL who underwent transrectal ultrasound-guided biopsy were enrolled at 16 Chinese medical centers from January 1st,2010 to December 31st,2013.Total and free serum PSA determinations were performed using three types of electro-chemiluminescence immunoassays recalibrated to the World Health Organization(WHO)standard.The diagnostic accuracy of PSA,%fPSA,and %fPSA in combination with PSA(%fPSA t PSA)was determined using the area under the receiver operating characteristic(ROC)curve(AUC).Results:A total of 2310 consecutive men with PSA levels between 4.0 and 10.0 ng/mL were included,and the detection rate of PCa was 25.1%.The AUC of%fPSA and %fPSA t PSA in predicting any PCa was superior to PSA alone in men aged≥60 years(0.623 vs.0.534,p<0.0001)but not in men aged 40e59 years(0.517 vs.0.518,p=0.939).Similar result was yield in predicting HGPCa.Conclusion:In a clinical setting of Chinese men with 4.0e10.0 ng/mL PSA undergoing initial prostate biopsy,adding %fPSA to PSA can moderately improve the diagnostic accuracy for any PCa and HGPCa compared with PSA alone in patients≥60 but not in patients aged 40-59 years.
文摘Recent researches focused on developing robust blast load mitigation systems due to the threats of terrorist attacks.One of the main embraced strategies is the structural systems that use mitigation techniques.They are developed from a combination of structural elements and described herein as conventional systems.Among the promising techniques is that redirect the waves propagation through hollow tubes.The blast wave propagation through tubes provides an efficient system since it combines many blast wave phenomena,such as reflection,diffraction,and interaction.In this research,a novel blast load mitigation system,employed as a protection fence,is developed using a technique similar to the technique of the bent tube in manipulating the shock-wave.The relative performance of the novel system to the conventional system is evaluated based on mitigation percent criteria.Performances of both systems are calculated through numerical simulation.The proposed novel system proved to satisfy high performance in mitigating the generated blast waves from charges weight up to 500 kg TNT at relatively small standoff distances(5 m and 8 m).It mitigates at least 94%of the blast waves,which means that only 6%of that blast impulse is considered as the applied load on the targeted structure.
文摘Percent elongation of ductile metal in uniaxial tension due to non-homogeneity was analyzed based on gradient-dependent plasticity. Three assumptions are used to get the analytical solution of percent elongation: one is static equilibrium condition in axial direction; another is that plastic volumetric strain is zero in necking zone; the other is that the diameter in unloading zone remains constant after strain localization is initiated. The strain gradient term was introduced into the yield function of classical plastic mechanics to obtain the analytical solution of distributed plastic strain. Integrating the plastic strain and considering the influence of necking on plastic elongation, a one-dimensional analytical solution of percent elongation was proposed. The analytical solution shows that the percent elongation is inversely proportional to the gauge length, and the solution is formally similar to earlier empirical formula proposed by Barba. Comparisons of existing experimental results and present analytical solutions for relation between load and total elongation and for relation between percent elongation and gauge length were carried out and the new mechanical model for percent elongation was verified. Moreover, higher ductility, toughness and heterogeneity can cause much larger percentage elongation, which coincides with usual viewpoints.
文摘Objective To evaluate using prostate specific antigen (PSA) and percent free PSA(fPSA) for the diagnosis of prostate cancer(Pca) and benign prostate hyperplasia(BPH). Methods 315 men with BPH and 55 men with Pca were randomly chosen, serum fPSA and total PSA were determined by ELISA and then we compared the sensitivity and specificity of PSA and percent fPSA for the diagnosis of Pca. Results While using PSA and percent fPSA for the diagnosis of prostate cancer, the sensitivity was similar (89.8% vs. 94.5%, P> 0.05), but the specificity was significanty different (52.7% vs. 89.8%, P< 0.005). Conclusions Using percent fPSA might decrease false-positive and avoid 37.1% negative biopsies as compared with PSA, it is very valuable for the diagnosis of Pca.
文摘Microalloyed linepipe steels were first introduced in 1959 at strength levels around 52-60 ksi [1] [2].The steels were generally strengthened by niobium or vanadium used singly.As strengths levels increased to X-70 in the early 1970’s niobium and vanadium were used in combination and controlled rolling was introduced on a broad basis.Higher strengths decrease tolerance for impurities and non-metallic inclusions which required improved steelmaking practices.Sulfur,carbon,and nitrogen were reduced and continuous casting was increasingly applied which required improved ladle refining and deoxidation practices.Niobium-molybdenum steels were introduced by IPSCO in 1972 [3] and by Italsider in 1974 [4].Steels with higher niobium contents were also introduced in the early 1970’s but available steelmaking technologies limited the use of optimum niobium to carbon ratios,i.e.those approaching stoichiometry.Nevertheless the steels benefited from the effect of niobium in retarding austenite recrystallization at relatively high rolling temperatures and they developed attractive combinations of strength and toughness in old manufacturing facilities using simple (relaxed) rolling schedules.Fluctuations in the price of molybdenum and vanadium in the past decade and expanded application of API Grade X-80 linepipe,have led to more widespread use of niobium contents up to 0.11 percent,in combination with 0.02-0.03 percent carbon (near stoichiometry) thus maximizing the effects of solute niobium during rolling,in lowering transformation temperature,and thereby reducing reliance on other alloying,often expensive,elements.The history of these developments will be presented and applications of the concept will be summarized.
文摘The purpose of this study is to evaluate the relationship between %HRmax and %vVO2max at constant efforts made at different intensities. In randomized order, males healthy subjects (Age: 25 ± 7 years, Weight: 70 ± 11 kg, VO2max: 55 ± 8 ml·kg–1·min–1) were divided into two groups, a trained one with more than 3 training sessions per week (n = 10) a moderately trained one with 3 drives or less per week (n = 15). The difference between the two groups corresponds to a time to exhaustion above and below 40 min at 80% vVO2max. All subjects performed 5 tests with a gradual increase in speed of 1 km·h–1 every 2 min and 4 constant speed tests at 60%, 70%, 80% and 90% VO2max. All test were performed at the same time of day (i.e., 18:00 h). The results of this study showed that eighteen collective regressions including different independent variables were developed to predict %HRmax. The individual equations developed, have r values between 0.974 and 0.993 and Syx, between 1.2 and 1.9 ml·kg–1·min–1, they are more accurate than the collective equations (one equation for all subjects) with r values between 0.81 to 0.89 and Syx, between 4.1 and 5.3 ml·kg–1·min–1. In conclusion, this study has demonstrated that the model of predictions of %HRmax from %vVO2max in triangular tests were not appropriate for rectangular efforts. From the equations developed, we find that the time to exhaustion at 90% vVO2max is the best predictor of level of endurance then the time limit to 80% vVO2max.
文摘China’s consumer price index (CPI), the main gauge of inflation, rose 4 percent in October from a year earlier, the National Bureau of Statistics said on Tuesday. The figure, compared with 4.6 percent in September, 4.9 percent in August,
文摘2009 was a disappointing year to export sector. In January to November of 2009, China’s textile and garment exports fell by 11.02percent year on year to US $154.12 billion,
文摘Efficient traffic signal system management plays a pivotal role in reducing traffic conges-tion and improving traffic mobility on urban roads.The applications of the automated traf-fic signal performance measures(ATSPMs)revolutionize the way of proactively managing and evaluating traffic signal systems through a suite of performance measures.The percent arrival on red(PAoR)is one of the commonly used progression performance measures in the ATSPMs to characterize vehicle arrivals at the intersection.However,the accuracy of PAoR to assess arterial signal coordination is restricted by configuration limitations of advance detectors and remains to be further explored.To address this problem,this research proposes an easy-to-use trajectory-based performance measure,i.e.,arterial through percent arrival on red(ATPAoR),for arterial signal coordination performance eval-uation and presents the general procedures to calculate ATPAoRs from connected vehicle data.A case study is carried out to implement the proposed ATPAoR and investigate the relationship between the ATPAoR and the PAoR.It is found that the combination of the time-space diagram(TSD)and arterial through-vehicle trajectories is effective in the actual arterial signal coordination performance visualization,ATPAoR result interpretation,and potential timing improvement recommendations.The PAoRs are found to be greater than the ATPAoRs in undersaturated conditions,and the PAoRs above 60%are recommended to identify poor arterial signal coordination design.The historical TSD can be utilized to verify the accuracy of PAoR to evaluate the actual arterial signal coordination when vehicle tra-jectory data are unavailable.
基金supported by the Guangzhou Laboratory Project(SRPG22-007)the Guangzhou Laboratory Project(GZNL2024A01004)the National Key Research and Development Program of China(2021YFC2301604).
文摘Objective:This study aims to assess the feasibility of evaluating the COVID-19 epidemic trend through monitoring the positive percentage of SARS-CoV-19 RNA in wastewater.Method:The study collected data from January to August 2023,including the number of reported cases,the positive ratio of nucleic acid samples in sentinel hospitals,the incidence rate of influenza-like symptoms in students,and the positive ratio of wastewater samples in different counties and districts in Shangrao City.Wastewater samples were obtained through grabbing and laboratory testing was completed within 24 h.The data were then normalized using Z-score normalization and analyzed for lag time and correlation using the xcorr function and Spearman correlation coefficient.Results:A total of 2797 wastewater samples were collected.The wastewater monitoring study,based on sampling point distribution,was divided into two phases.Wuyuan County consistently showed high levels of positive ratio in wastewater samples in both phases,reaching peak values of 91.67%and 100%respectively.The lag time analysis results indicated that the peak positive ratio in all wastewater samples in Shangrao City appeared around 2 weeks later compared to the other three indicators.The correlation analysis revealed a strong linear correlation across all four types of data,with Spearman correlation coefficients ranging from 0.783 to 0.977,all of which were statistically significant.Conclusion:The positive ratio of all wastewater samples in Shangrao City accurately reflected the COVID-19 epidemic trend from January to August 2023.This study confirmed the lag effect of wastewater percent positive and its strong correlation with the reported incidence rate and the positive ratio of nucleic acid samples in sentinel hospitals,supporting the use of wastewater percent positive monitoring as a supplementary tool for infectious disease surveillance in the regions with limited resources.
基金supported by the National Natural Science Foundation of China(grant numbers:82273721,82304220)Cooperation Fund of CHCAMS and SZCH(grant number:CFA202201003).
文摘Background While China’s socioeconomic transformation has driven divergent trends in gastrointestinal cancers,comprehensive data on esophageal,gastric,and liver cancer burden remain limited.This study examines the global burden of esophageal,gastric,and liver cancers in 2022 and analyzes the trends of age-standardized incidence and mortality rate(ASRs)in China from 2000 to 2018,thereby providing evidence for the formulation of cancer control strategies.Methods The global burden of esophageal,gastric and liver cancers including the estimated number of cases and deaths and the ASRs for incidence and mortality were from GLOBALCAN 2022 dataset.Data from 22 cancer registries in China were employed for the trend analysis of the ASRs for incidence and mortality of these three cancers.The Joinpoint model was used to compute the average annual percentage change(AAPC)of the incidence and mortality of the three cancers from 2000 to 2018.Results Globally,esophageal,gastric and liver cancers accounted for 11.8%of incident cancer cases and 19.1%of cancer deaths.China bore a disproportionately high burden,representing 43.8%,37.0%,and 42.4%of global esophageal,gastric,and liver cancer cases respectively,and 42.1%,39.4%,and 41.7%of corresponding deaths.However,the ASRs for incidence and mortality for all three cancers declined significantly in China(2000–2018),with absolute case numbers decreasing for gastric and esophageal cancers during 2010–2022.Age-specific analysis revealed most pronounced declines in incidence and mortality in populations under 40 years old,with AAPCs of less than–6.0%for esophageal cancer,around–4.0%for gastric cancer,and approximately–2.0%for liver cancer.Conclusions China has achieved remarkable progress in controlling esophageal,gastric and liver cancers,yet these malignancies remain major public health challenges.Future efforts should intensify existing prevention measures while expanding screening programs,particularly for aging populations.These findings offer valuable insights for regions undergoing similar epidemiological transitions.
