Metal foams have been intensively studied as three-dimensional （3-D） bulk mass-support for various applications because of their high conductivities and attractive mechanical properties. However, the relatively low ...Metal foams have been intensively studied as three-dimensional （3-D） bulk mass-support for various applications because of their high conductivities and attractive mechanical properties. However, the relatively low surface area of conventional metal foams largely limits their performance in applications such as charge storage. Here, we present a convenient electrochemical method for addressing this problem using Cu foams as an example. High surface area Cu foams are fabricated in a one-pot one-step manner by repetitive electrodeposition and dealloying treatments. The obtained Cu foams exhibit greatly improved performance for different applications like surface enhanced Raman spectroscopy （SERS） substrates and 3-D bulk supercapacitor electrodes.展开更多
The construction of electrode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has gradually been an appealing and attractive technology in energy storage research field.In the present work,a fac...The construction of electrode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has gradually been an appealing and attractive technology in energy storage research field.In the present work,a facile strategy of synthesizing ultrathin amorphous/nanocrystal dual-phase P-doped Bi_(2)MoO_(6)(denoted as P-BiMO)nanosheets via a one-step wet-chemical synthesis approach is explored.Quite distinct from conventional two-dimensional(2D)nanosheets,our newly developed ultrathin P-BiMO nanosheets exhibit a unique tunable amorphous/nanocrystalline dual-phase structure with several compelling advantages including fast ion exchange ability and superb volume change buffer capability.The experimental results reveal that our prepared P-BiMO-6 electrode delivers an excellent reversible capacity of 509.6 mA·g^(−1) after continuous 1,500 cycles at the current densities of 1,500 mA·g^(−1) and improved rate performance for LIBs.In the meanwhile,the P-BiMO-6 electrode also shows a reversible capacity of 300.6 mA·g^(−1) after 100 cycles at 50 mA·g^(−1) when being used as the SIBs electrodes.This present work uncovers an effective dual-phase nanosheet structure to improve the performance of batteries,providing an attractive paradigm to develop superior electrode materials.展开更多
Objective:To explore the risk factors and pregnancy outcomes in women with a history of cesarean section complicated by placenta accreta(PA).Methods:This case-control study included clinical data from singleton mother...Objective:To explore the risk factors and pregnancy outcomes in women with a history of cesarean section complicated by placenta accreta(PA).Methods:This case-control study included clinical data from singleton mothers with a history of cesarean section in 11 public tertiary hospitals in seven provinces of China between January 2017 and December 2017.According to the intraoperative findings after delivery,the study population was divided into PA and non-PA groups.We compared the pregnancy outcomes between the two groups,used multivariate logistic regression to analyze the risk factors for placental accreta.Results:For this study we included 11,074 pregnant women with a history of cesarean section;and of these,869 cases were in the PA group and 10,205 cases were in the non-PA group.Compared with the non-PA group,the probability of postpartum hemorrhage(236/10,205,2.31%vs.283/869,32.57%),severe postpartum hemorrhage(89/10,205,0.87%vs.186/869,21.75%),diffuse intravascular coagulation(3/10,205,0.03%vs.4/869,0.46%),puerperal infection(33/10,205,0.32%vs.12/869,1.38%),intraoperative bladder injury(1/10,205,0.01%vs.16/869,1.84%),hysterectomy(130/10,205,1.27%vs.59/869,6.79%),and blood transfusion(328/10,205,3.21%vs.231/869,26.58%)was significantly increased in the PA group(P<0.05).At the same time,the neonatal birth weight 3250.00(2950.00–3520.00)g vs.2920.00(2530.00–3250.00)g),the probability of neonatal comorbidities(245/10,205,2.40%vs.61/869,7.02%),and the rate of neonatal intensive care unit admission(817/10,205,8.01%vs.210/869,24.17%)also increased significantly(P<0.05).Weight(odds ratio)(OR)=1.03,95%confidence interval(CI):1.01–1.05)),parity(OR=1.18,95%CI:1.03–1.34),number of miscarriages(OR=1.31,95%CI:1.17–1.47),number of previous cesarean sections(OR=2.57,95%CI:2.02–3.26),history of premature rupture of membrane(OR=1.61,95%CI:1.32–1.96),previous cesarean-section transverse incisions(OR=1.38,95%CI:1.12–1.69),history of placenta previa(OR=2.44,95%CI:1.50–3.96),and the combination of prenatal hemorrhage(OR=9.95,95%CI:8.42–11.75)and placenta previa(OR=91.74,95%CI:74.11–113.56)were all independent risk factors for PA.Conclusion:There was an increased risk of adverse outcomes in pregnancies complicated by PA in women with a history of cesarean section,and this required close clinical attention.Weight before pregnancy,parity,number of miscarriages,number of previous cesarean sections,history of premature rupture of membranes,past transverse incisions in cesarean sections,a history of placenta previa,prenatal hemorrhage,and placenta previa were independent risk factors for pregnancies complicated with PA in women with a history of cesarean section.These independent risk factors showed a high value in predicting the risk for placentab accreta in pregnancies of women with a history of cesarean section.展开更多
Objective: To investigate whether the fetal gender affects the incidence of pre-eclampsia (PE) and fetal growth restriction (FGR) in singleton and twin pregnancies.Methods: This was a 10-year single-center, retrospect...Objective: To investigate whether the fetal gender affects the incidence of pre-eclampsia (PE) and fetal growth restriction (FGR) in singleton and twin pregnancies.Methods: This was a 10-year single-center, retrospective, cohort study from January 2009 to January 2019. A total of 57,129 singleton and 3699 twin pregnancies aged between 18-55 years old were recruited at the Third Affiliated Hospital of Guangzhou Medical University, China. We used multivariable logistic regression to analyze the effect of fetal gender on the incidence of PE and FGR.Results: In singleton pregnancies, the incidence rates of PE and FGR with a female fetus were higher than those with a male fetus (6.4% (1713/26,793)vs. 5.9% (1803/30,336),P < 0.05 and 3.5% (932/26,793)vs. 2.4% (745/30,336),P < 0.05, respectively). A female fetus was an independent risk factor for either PE or FGR (adjusted odds ratio: 1.169 or 1.563;95% confidence interval: 1.036-1.319 or 1.349-1.810, respectively). In twin pregnancies, the incidence of early-onset PE was greater in pregnancies with two females compared with two males or one male plus one female (4.6% (46/1003)vs. 4.1% (54/1305)vs. 2.4% (33/1391),P < 0.05). Female-female twins was an independent risk factor for PE (adjusted odds ratio: 1.367, 95% confidence interval: 1.011-1.849), especially early-onset PE.Conclusion: The female fetus was associated with PE in both singleton and twin pregnancies and was also a risk factor of FGR in singleton pregnancies.展开更多
文摘Metal foams have been intensively studied as three-dimensional （3-D） bulk mass-support for various applications because of their high conductivities and attractive mechanical properties. However, the relatively low surface area of conventional metal foams largely limits their performance in applications such as charge storage. Here, we present a convenient electrochemical method for addressing this problem using Cu foams as an example. High surface area Cu foams are fabricated in a one-pot one-step manner by repetitive electrodeposition and dealloying treatments. The obtained Cu foams exhibit greatly improved performance for different applications like surface enhanced Raman spectroscopy （SERS） substrates and 3-D bulk supercapacitor electrodes.
基金supported by Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shenzhen Park Project:HZQB-KCZYB-2020030the National Key R&D Program of China(Project No.2017YFA0204403)Hong Kong Innovation and Technology Commission via the Hong Kong Branch of National Precious Metals Material Engineering Research Center.
文摘The construction of electrode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs)has gradually been an appealing and attractive technology in energy storage research field.In the present work,a facile strategy of synthesizing ultrathin amorphous/nanocrystal dual-phase P-doped Bi_(2)MoO_(6)(denoted as P-BiMO)nanosheets via a one-step wet-chemical synthesis approach is explored.Quite distinct from conventional two-dimensional(2D)nanosheets,our newly developed ultrathin P-BiMO nanosheets exhibit a unique tunable amorphous/nanocrystalline dual-phase structure with several compelling advantages including fast ion exchange ability and superb volume change buffer capability.The experimental results reveal that our prepared P-BiMO-6 electrode delivers an excellent reversible capacity of 509.6 mA·g^(−1) after continuous 1,500 cycles at the current densities of 1,500 mA·g^(−1) and improved rate performance for LIBs.In the meanwhile,the P-BiMO-6 electrode also shows a reversible capacity of 300.6 mA·g^(−1) after 100 cycles at 50 mA·g^(−1) when being used as the SIBs electrodes.This present work uncovers an effective dual-phase nanosheet structure to improve the performance of batteries,providing an attractive paradigm to develop superior electrode materials.
基金supported by grants from the National Key R&D Program of China(No.2016YFC1000405,2017YFC1001402,and 2018YFC10029002)the National Natural Science Foundation(No.81830045,81671533,and 82071652).
文摘Objective:To explore the risk factors and pregnancy outcomes in women with a history of cesarean section complicated by placenta accreta(PA).Methods:This case-control study included clinical data from singleton mothers with a history of cesarean section in 11 public tertiary hospitals in seven provinces of China between January 2017 and December 2017.According to the intraoperative findings after delivery,the study population was divided into PA and non-PA groups.We compared the pregnancy outcomes between the two groups,used multivariate logistic regression to analyze the risk factors for placental accreta.Results:For this study we included 11,074 pregnant women with a history of cesarean section;and of these,869 cases were in the PA group and 10,205 cases were in the non-PA group.Compared with the non-PA group,the probability of postpartum hemorrhage(236/10,205,2.31%vs.283/869,32.57%),severe postpartum hemorrhage(89/10,205,0.87%vs.186/869,21.75%),diffuse intravascular coagulation(3/10,205,0.03%vs.4/869,0.46%),puerperal infection(33/10,205,0.32%vs.12/869,1.38%),intraoperative bladder injury(1/10,205,0.01%vs.16/869,1.84%),hysterectomy(130/10,205,1.27%vs.59/869,6.79%),and blood transfusion(328/10,205,3.21%vs.231/869,26.58%)was significantly increased in the PA group(P<0.05).At the same time,the neonatal birth weight 3250.00(2950.00–3520.00)g vs.2920.00(2530.00–3250.00)g),the probability of neonatal comorbidities(245/10,205,2.40%vs.61/869,7.02%),and the rate of neonatal intensive care unit admission(817/10,205,8.01%vs.210/869,24.17%)also increased significantly(P<0.05).Weight(odds ratio)(OR)=1.03,95%confidence interval(CI):1.01–1.05)),parity(OR=1.18,95%CI:1.03–1.34),number of miscarriages(OR=1.31,95%CI:1.17–1.47),number of previous cesarean sections(OR=2.57,95%CI:2.02–3.26),history of premature rupture of membrane(OR=1.61,95%CI:1.32–1.96),previous cesarean-section transverse incisions(OR=1.38,95%CI:1.12–1.69),history of placenta previa(OR=2.44,95%CI:1.50–3.96),and the combination of prenatal hemorrhage(OR=9.95,95%CI:8.42–11.75)and placenta previa(OR=91.74,95%CI:74.11–113.56)were all independent risk factors for PA.Conclusion:There was an increased risk of adverse outcomes in pregnancies complicated by PA in women with a history of cesarean section,and this required close clinical attention.Weight before pregnancy,parity,number of miscarriages,number of previous cesarean sections,history of premature rupture of membranes,past transverse incisions in cesarean sections,a history of placenta previa,prenatal hemorrhage,and placenta previa were independent risk factors for pregnancies complicated with PA in women with a history of cesarean section.These independent risk factors showed a high value in predicting the risk for placentab accreta in pregnancies of women with a history of cesarean section.
基金National Key R&D Program of China(No. 2016YFC1000405, 2017YFC1001402, 2018YFC1004104, and 2018YFC10029002)National Natural Science Foundation(No. 81830045, 81671533, 81571518, and 81971415)General program of Guangdong province Natural Science Foundation(No. 2020A1515010273)。
文摘Objective: To investigate whether the fetal gender affects the incidence of pre-eclampsia (PE) and fetal growth restriction (FGR) in singleton and twin pregnancies.Methods: This was a 10-year single-center, retrospective, cohort study from January 2009 to January 2019. A total of 57,129 singleton and 3699 twin pregnancies aged between 18-55 years old were recruited at the Third Affiliated Hospital of Guangzhou Medical University, China. We used multivariable logistic regression to analyze the effect of fetal gender on the incidence of PE and FGR.Results: In singleton pregnancies, the incidence rates of PE and FGR with a female fetus were higher than those with a male fetus (6.4% (1713/26,793)vs. 5.9% (1803/30,336),P < 0.05 and 3.5% (932/26,793)vs. 2.4% (745/30,336),P < 0.05, respectively). A female fetus was an independent risk factor for either PE or FGR (adjusted odds ratio: 1.169 or 1.563;95% confidence interval: 1.036-1.319 or 1.349-1.810, respectively). In twin pregnancies, the incidence of early-onset PE was greater in pregnancies with two females compared with two males or one male plus one female (4.6% (46/1003)vs. 4.1% (54/1305)vs. 2.4% (33/1391),P < 0.05). Female-female twins was an independent risk factor for PE (adjusted odds ratio: 1.367, 95% confidence interval: 1.011-1.849), especially early-onset PE.Conclusion: The female fetus was associated with PE in both singleton and twin pregnancies and was also a risk factor of FGR in singleton pregnancies.
