美国能源部(DOE)和美国国家航空航天局(NASA)正在合作研究开发摄入放射性核素后所致大脑剂量的方法,重点是高传能线密度(LET)粒子对大脑的影响,并试图提供与保护相关的大脑剂量学的新知识,以前尚未见到这方面的研究报道。目前,国际放射...美国能源部(DOE)和美国国家航空航天局(NASA)正在合作研究开发摄入放射性核素后所致大脑剂量的方法,重点是高传能线密度(LET)粒子对大脑的影响,并试图提供与保护相关的大脑剂量学的新知识,以前尚未见到这方面的研究报道。目前,国际放射防护委员会(ICRP)也没有摄入放射性核素后对脑组织辐射剂量的模型建议。美国能源部的早期工作人员(例如,来自洛斯阿拉莫斯国家实验室,Mallinckrodt Chemical Works,Mound和Rocketdyne)中存在摄入放射性核素的人员队列。展开更多
In 1987, the Montreal Protocol prohibited the worldwide use and production of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) and hydro fluorocarbons (HFCs) were proposed as alternative refrigerants. U...In 1987, the Montreal Protocol prohibited the worldwide use and production of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) and hydro fluorocarbons (HFCs) were proposed as alternative refrigerants. Unfortunately, HFCs have non negligible global warning potential and therefore new refrigerants must be proposed or old refrigerants must be used associated with HFC. Accurate experimental thermodynamic data and predictive techniques are required for better under-standing of the performance of the newly proposed refrigerants. In this communication, experimental techniques based on either analytic or synthetic methods are first described. Data are reported. Then two newly developed predictive models based on thermodynamic approach with the isofugacity criterion and artificial neural network method are presented. The results can provide better evaluation of refrigerants, especially with the aim of studying global warning effects.展开更多
Background Haloperidol is the most frequently prescribed antipsycbotic for delirium symptoms. The risk of QTc prolongation often raises concerns, although the effect of haloperidol on QTc interval has not yet been inv...Background Haloperidol is the most frequently prescribed antipsycbotic for delirium symptoms. The risk of QTc prolongation often raises concerns, although the effect of haloperidol on QTc interval has not yet been investigated in a randomised placebo-controlled fixed-dose study. Methods A subanalysis of a randomised double-blind placebo-controlled study was conducted to evaluate the effect of prophylactic haloperidol 1 mg or placebo 1 mg orally twice-daily （maximum of 14 doses） on QTc interval in patients aged 70 years and over. Bedside, 12-lead ECGs were recorded before, during and after the one-week intervention period. Automatic QTc measurements were ob- tained in addition to manual measurements of QT and RR intervals, blinded for treatment status. Manual measurements were corrected （QTc） using Bazett （QTc-B）, Framingham （QTc-Fa）, Fridericia （QTc-Fi） and Hodges （QTc-H） methods. Mixed model analyses were used to test for differences in longitudinal course of QTc between patients receiving haloperidol and placebo. Results ECG recordings of 72 patients （haloperidol n = 38） were analysed, 45.8% male. Median （range） haloperidol serum concentration on day 4 was 0.71 （0.32-1.82） μg/L （n = 23）. Longitudinal course of mean QTc did not significantly differ between treatment arms for any of the automatic or manually derived QTc values. Conclusions Low dose oral haloperidol did not result in QTc prolongation in older acutely hospitalised patients. Results may not be generalizable to patients with existing ECG abnormalities such as atrial fibrillation.展开更多
文摘美国能源部(DOE)和美国国家航空航天局(NASA)正在合作研究开发摄入放射性核素后所致大脑剂量的方法,重点是高传能线密度(LET)粒子对大脑的影响,并试图提供与保护相关的大脑剂量学的新知识,以前尚未见到这方面的研究报道。目前,国际放射防护委员会(ICRP)也没有摄入放射性核素后对脑组织辐射剂量的模型建议。美国能源部的早期工作人员(例如,来自洛斯阿拉莫斯国家实验室,Mallinckrodt Chemical Works,Mound和Rocketdyne)中存在摄入放射性核素的人员队列。
文摘In 1987, the Montreal Protocol prohibited the worldwide use and production of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) and hydro fluorocarbons (HFCs) were proposed as alternative refrigerants. Unfortunately, HFCs have non negligible global warning potential and therefore new refrigerants must be proposed or old refrigerants must be used associated with HFC. Accurate experimental thermodynamic data and predictive techniques are required for better under-standing of the performance of the newly proposed refrigerants. In this communication, experimental techniques based on either analytic or synthetic methods are first described. Data are reported. Then two newly developed predictive models based on thermodynamic approach with the isofugacity criterion and artificial neural network method are presented. The results can provide better evaluation of refrigerants, especially with the aim of studying global warning effects.
文摘Background Haloperidol is the most frequently prescribed antipsycbotic for delirium symptoms. The risk of QTc prolongation often raises concerns, although the effect of haloperidol on QTc interval has not yet been investigated in a randomised placebo-controlled fixed-dose study. Methods A subanalysis of a randomised double-blind placebo-controlled study was conducted to evaluate the effect of prophylactic haloperidol 1 mg or placebo 1 mg orally twice-daily （maximum of 14 doses） on QTc interval in patients aged 70 years and over. Bedside, 12-lead ECGs were recorded before, during and after the one-week intervention period. Automatic QTc measurements were ob- tained in addition to manual measurements of QT and RR intervals, blinded for treatment status. Manual measurements were corrected （QTc） using Bazett （QTc-B）, Framingham （QTc-Fa）, Fridericia （QTc-Fi） and Hodges （QTc-H） methods. Mixed model analyses were used to test for differences in longitudinal course of QTc between patients receiving haloperidol and placebo. Results ECG recordings of 72 patients （haloperidol n = 38） were analysed, 45.8% male. Median （range） haloperidol serum concentration on day 4 was 0.71 （0.32-1.82） μg/L （n = 23）. Longitudinal course of mean QTc did not significantly differ between treatment arms for any of the automatic or manually derived QTc values. Conclusions Low dose oral haloperidol did not result in QTc prolongation in older acutely hospitalised patients. Results may not be generalizable to patients with existing ECG abnormalities such as atrial fibrillation.
