Background：The currently available polysomnography （PSG） equipments and operating personnel are facing increasing pressure,such situation may result in the problem that a large number of obstructive sleep apnea （...Background：The currently available polysomnography （PSG） equipments and operating personnel are facing increasing pressure,such situation may result in the problem that a large number of obstructive sleep apnea （OSA） patients cannot receive timely diagnosis and treatment,we sought to develop a nomogram quantifying the risk of OSA for a better decision of using PSG,based on the clinical syndromes and the demographic and anthropometric characteristics.Methods：The nomogram was constructed through an ordinal logistic regression procedure.Predictive accuracy and performance characteristics were assessed with the area under the curve （AUC） of the receiver operating characteristics and calibration plots,respectively.Decision curve analyses were applied to assess the net benefit of the nomogram.Results：Among the 401 patients,73 （18.2%） were diagnosed and grouped as the none OSA （apnea-hypopnea index [AHI] 〈5）,67 （16.7%） the mild OSA （5 ≤ AHI 〈 15）,82 （20.4%） the moderate OSA （15 ≤ AHI 〈 30）,and 179 （44.6%） the severe OSA （AHI ≥ 30）.The multivariable analysis suggested the significant factors were duration of disease,smoking status,difficulty of falling asleep,lack of energy,and waist circumference.A nomogram was created for the prediction of OSA using these clinical parameters and was internally validated using bootstrapping method.The discrimination accuracies of the nomogram for any OSA,moderate-severe OSA,and severe OSA were 83.8%,79.9%,and 80.5%,respectively,which indicated good calibration.Decision curve analysis showed that using nomogram could reduce the unnecessary polysomnography （PSG） by 10% without increasing the false negatives.Conclusions：The established clinical nomogram provides high accuracy in predicting the individual risk of OSA.This tool may help physicians better make decisions on PSG arrangement for the patients referred to sleep centers.展开更多
A series of reheating-isothermal holding experiments and compression tests were conducted on pristine magnesium alloy AZ91 extruded by equal channel angular extrusion （ECAE） and SiC particles （a volume fraction of ...A series of reheating-isothermal holding experiments and compression tests were conducted on pristine magnesium alloy AZ91 extruded by equal channel angular extrusion （ECAE） and SiC particles （a volume fraction of 15%） reinforced AZ91 composite （AZ91-SiCp） by regular extrusion. Dissolution of eutectic com- pounds and partial melting of the ct-Mg matrix occurred during the reheating of these materials. Spherical semisolid slurries of these materials were obtained when the reheating temperature and isothermal hold- ing time were 550℃ and 20 s, respectively. The presence of SiCp in AZ91-SiCp not only caused lower liquid fractions of semisolid slurries but also resulted in higher values of flow stress during semisolid compression tests. Both AZgl alloy and AZ91-SiCp composite exhibited better thixoforming properties at high temperatures. Segregation of SiCp did not occur during thixoforming of AZ91-SiCp composite after an isothermal holding at semisolid temperatures for 20 s.2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.展开更多
基金the National Key Research and Development Program of China (No. 2020YFC1909701)the National Natural Science Foundation of China (No. 52074050)Chongqing Science and Technology Bureau (Nos. cstc2019jcyjjqX0006, cstc2021ycjhbgzxm0075)。
文摘Background：The currently available polysomnography （PSG） equipments and operating personnel are facing increasing pressure,such situation may result in the problem that a large number of obstructive sleep apnea （OSA） patients cannot receive timely diagnosis and treatment,we sought to develop a nomogram quantifying the risk of OSA for a better decision of using PSG,based on the clinical syndromes and the demographic and anthropometric characteristics.Methods：The nomogram was constructed through an ordinal logistic regression procedure.Predictive accuracy and performance characteristics were assessed with the area under the curve （AUC） of the receiver operating characteristics and calibration plots,respectively.Decision curve analyses were applied to assess the net benefit of the nomogram.Results：Among the 401 patients,73 （18.2%） were diagnosed and grouped as the none OSA （apnea-hypopnea index [AHI] 〈5）,67 （16.7%） the mild OSA （5 ≤ AHI 〈 15）,82 （20.4%） the moderate OSA （15 ≤ AHI 〈 30）,and 179 （44.6%） the severe OSA （AHI ≥ 30）.The multivariable analysis suggested the significant factors were duration of disease,smoking status,difficulty of falling asleep,lack of energy,and waist circumference.A nomogram was created for the prediction of OSA using these clinical parameters and was internally validated using bootstrapping method.The discrimination accuracies of the nomogram for any OSA,moderate-severe OSA,and severe OSA were 83.8%,79.9%,and 80.5%,respectively,which indicated good calibration.Decision curve analysis showed that using nomogram could reduce the unnecessary polysomnography （PSG） by 10% without increasing the false negatives.Conclusions：The established clinical nomogram provides high accuracy in predicting the individual risk of OSA.This tool may help physicians better make decisions on PSG arrangement for the patients referred to sleep centers.
基金financially supported by the National Natural Science Foundation of China (No. 51605055)Chongqing Natural Science Foundation (No. cstc2016jcyj A1027)Fundamental Research Funds for the Central Universities (No. 0903005203307)
文摘A series of reheating-isothermal holding experiments and compression tests were conducted on pristine magnesium alloy AZ91 extruded by equal channel angular extrusion （ECAE） and SiC particles （a volume fraction of 15%） reinforced AZ91 composite （AZ91-SiCp） by regular extrusion. Dissolution of eutectic com- pounds and partial melting of the ct-Mg matrix occurred during the reheating of these materials. Spherical semisolid slurries of these materials were obtained when the reheating temperature and isothermal hold- ing time were 550℃ and 20 s, respectively. The presence of SiCp in AZ91-SiCp not only caused lower liquid fractions of semisolid slurries but also resulted in higher values of flow stress during semisolid compression tests. Both AZgl alloy and AZ91-SiCp composite exhibited better thixoforming properties at high temperatures. Segregation of SiCp did not occur during thixoforming of AZ91-SiCp composite after an isothermal holding at semisolid temperatures for 20 s.2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.
