The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical properties.Previous stud...The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical properties.Previous studies have demonstrated that the addition of Sc to aluminum alloys can improve both the microstructure and properties of the alloys.In this study,the effect of Sc on the Fe-rich phase and properties of the AA5052 aluminum alloy was studied by adding 0%,0.05%,0.2%,and 0.3%Sc.The results show that with the increase of Sc,the coarse needle-like Fe-rich phase gradually transforms into Chinese-script and then nearly spherical particles,reduce the size of Fe-rich phase,and refine the grain with increase of high angle grain boundaries(HAGBs).These microstructure changes enhance the strength of the AA5052 alloy through Sc addition.The ductility of the alloy is obviously improved because the addition of a lower amount of Sc changes the morphology of Fe-rich phase from needle-like into a Chinese-script,and it is subsequently reduced as a result of significant increase in HAGBs with increasing Sc content.展开更多
Vacuum die casting can reduce the'air entrapment'phenomenon during casting process.Based on the temperature measurements at metal-die interface with different processing parameters,such as slow shot speed(VL),...Vacuum die casting can reduce the'air entrapment'phenomenon during casting process.Based on the temperature measurements at metal-die interface with different processing parameters,such as slow shot speed(VL),high shot speed(VH),pouring temperature(Tp)and initial die temperature(Tm),inverse method was developed to determine the interfacial heat transfer coefficient(IHTC).The results indicate that a closer contact between the casting and die could be achieved when the vacuum system is used.It is found that the vacuum could strongly increase the values of IHTC and decrease the grain size in castings.The IHTC could have a higher peak value with increasing the Tp from680to720℃or the VL from0.1to0.4m/s.In addition,the influence of the VH and Tm on IHTC could be negligible.展开更多
Background Proton pump inhibitors(PPIs) are recommended by the latest guidelines to reduce the risk of bleeding in acute myocardial infarction(AMI) patients treated with dual antiplatelet therapy(DAPT). However, previ...Background Proton pump inhibitors(PPIs) are recommended by the latest guidelines to reduce the risk of bleeding in acute myocardial infarction(AMI) patients treated with dual antiplatelet therapy(DAPT). However, previous pharmacodynamic and clinical studies have reported controversial results on the interaction between PPI and the P2 Y12 inhibitor clopidogrel. We investigated the impact of PPIs use on in-hospital outcomes in AMI patients, aiming to provide a new insight on the value of PPIs. Methods A total of 23,380 consecutive AMI patients who received clopidogrel with or without PPIs in the China Acute Myocardial Infarction(CAMI) registry were analyzed. The primary endpoint was major adverse cardiovascular and cerebrovascular events(MACCE) defined as a composite of in-hospital cardiac death, re-infarction and stroke. Propensity score matching(PSM) was used to control potential baseline confounders. Multivariate logistic regression analysis was performed to evaluate the effect of PPIs use on MACCE and gastrointestinal bleeding(GIB). Results Among the whole AMI population, a large majority received DAPT and 67.5% were co-medicated with PPIs. PPIs use was associated with a decreased risk of MACCE(Before PSM OR: 0.857, 95% CI: 0.742-0.990, P = 0.0359;after PSM OR: 0.862, 95% CI: 0.768-0.949, P = 0.0245) after multivariate adjustment. Patients receiving PPIs also had a lower risk of cardiac death but a higher risk of complicating with stroke. When GIB occurred, an alleviating trend of GIB severity was observed in PPIs group. Conclusions Our study is the first nation-wide large-scale study to show evidence on PPIs use in AMI patients treated with DAPT. We found that PPIs in combination with clopidogrel was associated with decreased risk for MACCE in AMI patients, and it might have a trend to mitigate GIB severity. Therefore, PPIs could become an available choice for AMI patients during hospitalization.展开更多
High pressure die casting copper is used to produce rotors for induction motors to improve efficiency.Experiments were carried out for a special"step-shape"casting with different step thicknesses.Based on th...High pressure die casting copper is used to produce rotors for induction motors to improve efficiency.Experiments were carried out for a special"step-shape"casting with different step thicknesses.Based on the measured temperature inside the die,the interfacial heat transfer coefficient(IHTC)at the metal/die interface during vacuum die casting was evaluated by solving the inverse problem.The IHTC peak value was 4.5×10^3-11×10^3 W·m^-2·K^-1 under the basic operation condition.The influences of casting pressure,fast shot speed,pouring temperature and initial die surface temperature on the IHTC peak values were investigated.Results show that a greater casting pressure and faster shot speed could only increase the IHTC peak values at the location close to the ingate.An increase of pouring temperature and/or initial die surface temperature significantly increases the IHTC peak values.展开更多
Pure copper tensile bars were produced by conventional die casting(HPDC) and vacuum-assist die casting(VADC) processes. Porosity and mechanical properties were investigated by using optical microscopy(OM), scanning el...Pure copper tensile bars were produced by conventional die casting(HPDC) and vacuum-assist die casting(VADC) processes. Porosity and mechanical properties were investigated by using optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray computed tomography(XCT) and tensile tester. Results show that porosities including gas porosity and shrinkage porosity could be observed in copper castings. Since the application of vacuum could reduce filling related gas entrapment and facilitate solidification due to the increased heat transfer between metal and die, both number and size of the entrapped gases, as well as shrinkage porosities were significantly reduced in vacuum-assist die castings of pure copper. The porosity fraction decreased from 2.243% to 0.875% compared with that of the conventional die casting. Besides, mechanical properties were improved significantly, i.e., by 15% for ultimate tensile strength and three times for elongation.展开更多
BACKGROUND Congenital fiber-type disproportion(CFTD)is a form of congenital myopathy.CFTD is rare,especially when presenting in patients with critical illnesses.Here,we report a case of CFTD presenting with type II re...BACKGROUND Congenital fiber-type disproportion(CFTD)is a form of congenital myopathy.CFTD is rare,especially when presenting in patients with critical illnesses.Here,we report a case of CFTD presenting with type II respiratory failure after delivery and provide a review of the literature on CFTD.CASE SUMMARY A 30-year-old woman was admitted to the obstetrics department of our hospital with premature rupture of the fetal membrane and with 7 h of regular contractions.After delivery,the patient experienced a refractory type II respiratory failure.Physical examination along with diagnostic procedures such as electromyography and biopsy confirmed CFTD.Use of invasive ventilator followed by intermittent use of noninvasive ventilator attenuated her symptoms.The patient recovered after ventilator-assisted respiration and was weaned off the noninvasive ventilator on the seventh day postpartum.CONCLUSION Congenital myopathy should be considered a differential diagnosis for type II respiratory failures that cannot be attributed to other diseases.展开更多
Background： The effect of maternal weights on the risk of iron deficiency anemia （IDA） during pregnancy remains unclear. The study aimed to investigate the association between maternal weight indicators and IDA dur...Background： The effect of maternal weights on the risk of iron deficiency anemia （IDA） during pregnancy remains unclear. The study aimed to investigate the association between maternal weight indicators and IDA during pregnancy. Methods： We conducted a cohort study to examine the association between maternal weight indicators, including prepregnancy body mass index and the rate of gestational weight gain （GWG）, and the risk of IDA among Chinese pregnant women. Data about new-onset IDA at different trimesters from a national cross-sectional survey were collected; information regarding baseline variables and rate of GWG from women participating in the survey were retrospectively collected. Tested IDA and reported IDA were documented. Multilevel logistic regression to examine the association between maternal weight indicators and the risk of IDA after adjusting for potential confounders was conducted. Results： This study enrolled 11,782 pregnant women from 24 hospitals from September 19, 2016, to November 20, 2016. Among those, 1515 （12.9%） IDA events were diagnosed through test （test IDA）： 3915 （33.3%） were identified through test and patient reporting （composite IDA）. After adjusting for confounders and cluster effect of hospitals, underweight pregnant women, compared with normal women, were associated with higher risk of test IDA （adjusted odds ratio [aOR]： 1.35, 95% confidence interval [CI]： 1.17-1.57 and composite IDA （aOR： 1.35, 95% CI： 1.21-1.51）; on the contrary, overweight and obese women had lower risk of test IDA （aOR： 0.68, 95% CI： 0.54-0.86 overweight; aOR： 0.30, 95% CI： 0. 13-0.69 obese） and composite IDA （aOR： 0.77, 95% （71：0.67-0.90 overweight; aOR： 0.34, 95% CI： 0.21-0.55 obese）. The higher rate of GWG was associated with higher risk of IDA （test aOR： 1.86 95% CI： 1.26-2.76; composite aOR： 1.54, 95% CI： 1.16-2.03）. Conclusions： Pregnant women who are underweight betbre pregnancy and who have taster GWG are more likely to develop IDA. Enforced weight control during pregnancy and use of iron supplements, particularly among underweight women, may be warranted.展开更多
基金supported by the Key Research&Development Program of Yunnan Province(Grant numbers 202103AA080017,202203AE140011).
文摘The AA5052 aluminum alloy is widely used in automobile and aerospace manufacturing,and with the development of light-weight alloys,it is required that these materials exhibit better mechanical properties.Previous studies have demonstrated that the addition of Sc to aluminum alloys can improve both the microstructure and properties of the alloys.In this study,the effect of Sc on the Fe-rich phase and properties of the AA5052 aluminum alloy was studied by adding 0%,0.05%,0.2%,and 0.3%Sc.The results show that with the increase of Sc,the coarse needle-like Fe-rich phase gradually transforms into Chinese-script and then nearly spherical particles,reduce the size of Fe-rich phase,and refine the grain with increase of high angle grain boundaries(HAGBs).These microstructure changes enhance the strength of the AA5052 alloy through Sc addition.The ductility of the alloy is obviously improved because the addition of a lower amount of Sc changes the morphology of Fe-rich phase from needle-like into a Chinese-script,and it is subsequently reduced as a result of significant increase in HAGBs with increasing Sc content.
基金Project (2016YFB0301001) supported by the National Key Research and Development Program of ChinaProject (2015M580093) supported by the General Financial Grant from the China Postdoctoral Science Foundation of China
文摘Vacuum die casting can reduce the'air entrapment'phenomenon during casting process.Based on the temperature measurements at metal-die interface with different processing parameters,such as slow shot speed(VL),high shot speed(VH),pouring temperature(Tp)and initial die temperature(Tm),inverse method was developed to determine the interfacial heat transfer coefficient(IHTC).The results indicate that a closer contact between the casting and die could be achieved when the vacuum system is used.It is found that the vacuum could strongly increase the values of IHTC and decrease the grain size in castings.The IHTC could have a higher peak value with increasing the Tp from680to720℃or the VL from0.1to0.4m/s.In addition,the influence of the VH and Tm on IHTC could be negligible.
基金supported by the CAMS Innovation Fund for Medical Sciences (CIFMS, 2016-I2M-1-009)Twelfth Five-Year Planning Project of the Scientific and Technological Department of China (2011BAI11B02)National Natural Science Foundation of China (No 81670415)。
文摘Background Proton pump inhibitors(PPIs) are recommended by the latest guidelines to reduce the risk of bleeding in acute myocardial infarction(AMI) patients treated with dual antiplatelet therapy(DAPT). However, previous pharmacodynamic and clinical studies have reported controversial results on the interaction between PPI and the P2 Y12 inhibitor clopidogrel. We investigated the impact of PPIs use on in-hospital outcomes in AMI patients, aiming to provide a new insight on the value of PPIs. Methods A total of 23,380 consecutive AMI patients who received clopidogrel with or without PPIs in the China Acute Myocardial Infarction(CAMI) registry were analyzed. The primary endpoint was major adverse cardiovascular and cerebrovascular events(MACCE) defined as a composite of in-hospital cardiac death, re-infarction and stroke. Propensity score matching(PSM) was used to control potential baseline confounders. Multivariate logistic regression analysis was performed to evaluate the effect of PPIs use on MACCE and gastrointestinal bleeding(GIB). Results Among the whole AMI population, a large majority received DAPT and 67.5% were co-medicated with PPIs. PPIs use was associated with a decreased risk of MACCE(Before PSM OR: 0.857, 95% CI: 0.742-0.990, P = 0.0359;after PSM OR: 0.862, 95% CI: 0.768-0.949, P = 0.0245) after multivariate adjustment. Patients receiving PPIs also had a lower risk of cardiac death but a higher risk of complicating with stroke. When GIB occurred, an alleviating trend of GIB severity was observed in PPIs group. Conclusions Our study is the first nation-wide large-scale study to show evidence on PPIs use in AMI patients treated with DAPT. We found that PPIs in combination with clopidogrel was associated with decreased risk for MACCE in AMI patients, and it might have a trend to mitigate GIB severity. Therefore, PPIs could become an available choice for AMI patients during hospitalization.
文摘High pressure die casting copper is used to produce rotors for induction motors to improve efficiency.Experiments were carried out for a special"step-shape"casting with different step thicknesses.Based on the measured temperature inside the die,the interfacial heat transfer coefficient(IHTC)at the metal/die interface during vacuum die casting was evaluated by solving the inverse problem.The IHTC peak value was 4.5×10^3-11×10^3 W·m^-2·K^-1 under the basic operation condition.The influences of casting pressure,fast shot speed,pouring temperature and initial die surface temperature on the IHTC peak values were investigated.Results show that a greater casting pressure and faster shot speed could only increase the IHTC peak values at the location close to the ingate.An increase of pouring temperature and/or initial die surface temperature significantly increases the IHTC peak values.
文摘Pure copper tensile bars were produced by conventional die casting(HPDC) and vacuum-assist die casting(VADC) processes. Porosity and mechanical properties were investigated by using optical microscopy(OM), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), X-ray computed tomography(XCT) and tensile tester. Results show that porosities including gas porosity and shrinkage porosity could be observed in copper castings. Since the application of vacuum could reduce filling related gas entrapment and facilitate solidification due to the increased heat transfer between metal and die, both number and size of the entrapped gases, as well as shrinkage porosities were significantly reduced in vacuum-assist die castings of pure copper. The porosity fraction decreased from 2.243% to 0.875% compared with that of the conventional die casting. Besides, mechanical properties were improved significantly, i.e., by 15% for ultimate tensile strength and three times for elongation.
文摘BACKGROUND Congenital fiber-type disproportion(CFTD)is a form of congenital myopathy.CFTD is rare,especially when presenting in patients with critical illnesses.Here,we report a case of CFTD presenting with type II respiratory failure after delivery and provide a review of the literature on CFTD.CASE SUMMARY A 30-year-old woman was admitted to the obstetrics department of our hospital with premature rupture of the fetal membrane and with 7 h of regular contractions.After delivery,the patient experienced a refractory type II respiratory failure.Physical examination along with diagnostic procedures such as electromyography and biopsy confirmed CFTD.Use of invasive ventilator followed by intermittent use of noninvasive ventilator attenuated her symptoms.The patient recovered after ventilator-assisted respiration and was weaned off the noninvasive ventilator on the seventh day postpartum.CONCLUSION Congenital myopathy should be considered a differential diagnosis for type II respiratory failures that cannot be attributed to other diseases.
基金This study was supported by grants from the National Natural Science Foundation of China （No. 71704122）, the National Key Research and Development Program of Reproductive Health and Major Birth Defects Control and Prevention （No. 2016YFC 1000406）, and ＂Thousand Youth Talents Plan＂ of China （No. D1024002）.
文摘Background： The effect of maternal weights on the risk of iron deficiency anemia （IDA） during pregnancy remains unclear. The study aimed to investigate the association between maternal weight indicators and IDA during pregnancy. Methods： We conducted a cohort study to examine the association between maternal weight indicators, including prepregnancy body mass index and the rate of gestational weight gain （GWG）, and the risk of IDA among Chinese pregnant women. Data about new-onset IDA at different trimesters from a national cross-sectional survey were collected; information regarding baseline variables and rate of GWG from women participating in the survey were retrospectively collected. Tested IDA and reported IDA were documented. Multilevel logistic regression to examine the association between maternal weight indicators and the risk of IDA after adjusting for potential confounders was conducted. Results： This study enrolled 11,782 pregnant women from 24 hospitals from September 19, 2016, to November 20, 2016. Among those, 1515 （12.9%） IDA events were diagnosed through test （test IDA）： 3915 （33.3%） were identified through test and patient reporting （composite IDA）. After adjusting for confounders and cluster effect of hospitals, underweight pregnant women, compared with normal women, were associated with higher risk of test IDA （adjusted odds ratio [aOR]： 1.35, 95% confidence interval [CI]： 1.17-1.57 and composite IDA （aOR： 1.35, 95% CI： 1.21-1.51）; on the contrary, overweight and obese women had lower risk of test IDA （aOR： 0.68, 95% CI： 0.54-0.86 overweight; aOR： 0.30, 95% CI： 0. 13-0.69 obese） and composite IDA （aOR： 0.77, 95% （71：0.67-0.90 overweight; aOR： 0.34, 95% CI： 0.21-0.55 obese）. The higher rate of GWG was associated with higher risk of IDA （test aOR： 1.86 95% CI： 1.26-2.76; composite aOR： 1.54, 95% CI： 1.16-2.03）. Conclusions： Pregnant women who are underweight betbre pregnancy and who have taster GWG are more likely to develop IDA. Enforced weight control during pregnancy and use of iron supplements, particularly among underweight women, may be warranted.
