A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban （236）, rural （80） a...A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban （236）, rural （80） and industrial areas （97） were studied. Blood lead was analyzed using the Atomic Absorption Spectrophotometer （GFAAS）. Cognitive development was measured by the ＇McCarthy Scales of Children＇s Abilities Test＇ （MSCA）. Significant differences found in the mean cognitive scores between the urban （94.40）, industrial （102.90） and suburban children （101.24） （p 〈 0.001）, with the blood lead between the urban （3.66 p.g/dL）, industrial （3.54 μg/dL） and suburban children （3.04μg/dL） （p = 0.022）. Significant inverse correlations between blood lead and cognitive scores found for all groups （p 〈 0.001）, urban （p 〈 0.001） and suburban children （p 〈 0.001）. Low blood lead significantly influenced the cognitive development for all children after adjusting for confounders （p _〈 0.001）. The urban children＇s cognitive scores were significantly influenced by blood lead levels and household income （p 〈 0.001）. However, for the suburban children, the cognitive score were significantly influenced by the blood lead levels, the mothers＇ education, number of siblings, sequence in the family and the household income （p 〈 0.001 ）. Blood lead below 10μg/dL influenced the cognitive development. Urban children had higher blood lead but suburban children with lower blood lead were also vulnerable to the effect of lead on their cognitive development.展开更多
Displacement of a cardiac pacemaker lead or myocardial perforation by a lead is an infrequent complication of pacemaker implantation. While standard cardiac CT is useful for diagnosing such complications when routine ...Displacement of a cardiac pacemaker lead or myocardial perforation by a lead is an infrequent complication of pacemaker implantation. While standard cardiac CT is useful for diagnosing such complications when routine examinations can not, the potential risks associated with exposure to the high doses of radiation used in CT are of concern. Here, we report three cases </span><span style="font-family:"white-space:normal;">in which pacemaker lead displacement or myocardial perforation was definitively diagnosed by l</span><span style="font-family:"white-space:normal;">ow-dose cardiac CT used in the high-pitch spiral mode, when other more routine examinations failed to suggest their occurrence.</span><span style="font-family:"white-space:normal;"> </span><span style="font-family:"white-space:normal;">The mean dose of radiation used for definitively diagnosing the three patients was relatively low (2.19 mSv).展开更多
With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects,the defect-tolerant electronic and optical properties of lead halide perovskites have made ...With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects,the defect-tolerant electronic and optical properties of lead halide perovskites have made them appealing materials for high-efficiency,low-cost,solar cells and light-emitting devices.As such,recent observations of apparently deep-level and highly luminescent states in low-dimensional perovskites have attracted enormous attention as well as intensive debates.The observed green emission in 2D CsPb2Br5 and 0 D Cs4PbBr6 poses an enigma over whether it is originated from intrinsic point defects or simply from highly luminescent CsPbBr3 nanocrystals embedded in the otherwise transparent wide band gap semiconductors.The nature of deep-level edge emission in 2D Ruddlesden–Popper perovskites is also not well understood.In this mini review,the experimental evidences that support the opposing interpretations are analyzed,and challenges and root causes forthe controversy are discussed.Shortcomings in the current density functional theory approaches to modeling of properties and intrinsic point defects in lead halide perovskites are also noted.Selected experimental approaches are suggested to better correlate property with structure of a material and help resolve the controversies.Understanding and identification of the origin of luminescent centers will help design and engineer perovskites for wide device applications.展开更多
An experimental Paschen test setup has been established to analyze the quality of ITER current lead （CL） insulation and extend the research on Paschen＇s law under various conditions. Insulation problems can destroy...An experimental Paschen test setup has been established to analyze the quality of ITER current lead （CL） insulation and extend the research on Paschen＇s law under various conditions. Insulation problems can destroy a machine if a Paschen discharge is triggered by an insulation defect that is caused by faulty manufacturing, electromagnetic force, and thermal stress load with a certain degree of vacuum helium or pipe leakage. The results show that the CL insulation mock-up worked well under normal temperature and pressure. Besides, the mock-up also worked well in helium conditions and at 80 K temperature at different pressures. One area of CL insulation was severely destroyed when the 80 K test was conducted after 5 thermal cycles, resulting in Paschen discharge phenomenon. The breakdown voltage is maintained at a relatively low level under different pressure conditions; the change of breakdown voltage was mainly due to the change of pressure, and such change was in line with the Paschen law.展开更多
This Paper reports a new system for preparation of lead titanate powders by the Sol Gel method. In this system, basic lead lactate, (CH 3CHOHCOO) 2Pb, is used as the lead precursor instead of the widely used Pb(OOCCH ...This Paper reports a new system for preparation of lead titanate powders by the Sol Gel method. In this system, basic lead lactate, (CH 3CHOHCOO) 2Pb, is used as the lead precursor instead of the widely used Pb(OOCCH 3) 2·3H 2O and titanium tetrabutoxide monomer. This new system simplifies the chemical processing of precursor solutions of lead titanate, increases their stability in air, and offers good control Pb(Ti stoichiometry. The xerogel, obtained from the precursor solution by aging at low temperature, is found to have a higer inorganic content. Gel to ceramic conversion is achieved by calcining the xerogel from 400℃ to 800℃. The phase purity, particle size, morphology, compositional homogeneity of the gel derived powders are examined by XRD. TEM.IR and the slow reflection spectrum of partides are measured.展开更多
Some heart diseases need long-term monitoring to diagnose. In this paper, we present a wearable single lead ECG monitoring device with low power consumption based on MSP430 and single-lead ECG front-end AD8232, which ...Some heart diseases need long-term monitoring to diagnose. In this paper, we present a wearable single lead ECG monitoring device with low power consumption based on MSP430 and single-lead ECG front-end AD8232, which could acquire and store patient’s ECG data for 7 days continuously. This device is available for long-term wearing with a small volume. Also, it could detect user’s motion status with an acceleration sensor and supports Bluetooth 4.0 protocol. So it could be expanded to be a dynamic heart rate monitor and/or sleep quality monitor combined with smart phone. The device has huge potential of application for health care of human daily life.展开更多
采用固含量及pH值、SEM、IR、TGA/DSC等分析方法对两种木素进行理化性能分析。对分别采用这两种木素的12 V 70 Ah样品电池进行低温放电性能、充电接受能力和循环寿命性能验证。结果发现:两种木素在官能团及热重分析的第1个吸热峰存在差...采用固含量及pH值、SEM、IR、TGA/DSC等分析方法对两种木素进行理化性能分析。对分别采用这两种木素的12 V 70 Ah样品电池进行低温放电性能、充电接受能力和循环寿命性能验证。结果发现:两种木素在官能团及热重分析的第1个吸热峰存在差异。木素B对铅酸蓄电池的低温放电性能、25℃下17.5%DoD循环寿命和60℃下17.5%DoD循环寿命更有利。通过综合分析木素B的理化性能和电化学性能得出了木素B的最佳添加量。展开更多
文摘A study on to identify the relationship between blood lead and cognitive development was conducted on primary school children in Malaysia. About 413 children aged 62^/1 - 82^/1 years from urban （236）, rural （80） and industrial areas （97） were studied. Blood lead was analyzed using the Atomic Absorption Spectrophotometer （GFAAS）. Cognitive development was measured by the ＇McCarthy Scales of Children＇s Abilities Test＇ （MSCA）. Significant differences found in the mean cognitive scores between the urban （94.40）, industrial （102.90） and suburban children （101.24） （p 〈 0.001）, with the blood lead between the urban （3.66 p.g/dL）, industrial （3.54 μg/dL） and suburban children （3.04μg/dL） （p = 0.022）. Significant inverse correlations between blood lead and cognitive scores found for all groups （p 〈 0.001）, urban （p 〈 0.001） and suburban children （p 〈 0.001）. Low blood lead significantly influenced the cognitive development for all children after adjusting for confounders （p _〈 0.001）. The urban children＇s cognitive scores were significantly influenced by blood lead levels and household income （p 〈 0.001）. However, for the suburban children, the cognitive score were significantly influenced by the blood lead levels, the mothers＇ education, number of siblings, sequence in the family and the household income （p 〈 0.001 ）. Blood lead below 10μg/dL influenced the cognitive development. Urban children had higher blood lead but suburban children with lower blood lead were also vulnerable to the effect of lead on their cognitive development.
文摘Displacement of a cardiac pacemaker lead or myocardial perforation by a lead is an infrequent complication of pacemaker implantation. While standard cardiac CT is useful for diagnosing such complications when routine examinations can not, the potential risks associated with exposure to the high doses of radiation used in CT are of concern. Here, we report three cases </span><span style="font-family:"white-space:normal;">in which pacemaker lead displacement or myocardial perforation was definitively diagnosed by l</span><span style="font-family:"white-space:normal;">ow-dose cardiac CT used in the high-pitch spiral mode, when other more routine examinations failed to suggest their occurrence.</span><span style="font-family:"white-space:normal;"> </span><span style="font-family:"white-space:normal;">The mean dose of radiation used for definitively diagnosing the three patients was relatively low (2.19 mSv).
基金support from the Robert A.Welch Foundation(E-1728)National Science Foundation(EEC-1530753)supported by the State of Texas through the Texas Center for superconductivity at the University of Houston
文摘With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects,the defect-tolerant electronic and optical properties of lead halide perovskites have made them appealing materials for high-efficiency,low-cost,solar cells and light-emitting devices.As such,recent observations of apparently deep-level and highly luminescent states in low-dimensional perovskites have attracted enormous attention as well as intensive debates.The observed green emission in 2D CsPb2Br5 and 0 D Cs4PbBr6 poses an enigma over whether it is originated from intrinsic point defects or simply from highly luminescent CsPbBr3 nanocrystals embedded in the otherwise transparent wide band gap semiconductors.The nature of deep-level edge emission in 2D Ruddlesden–Popper perovskites is also not well understood.In this mini review,the experimental evidences that support the opposing interpretations are analyzed,and challenges and root causes forthe controversy are discussed.Shortcomings in the current density functional theory approaches to modeling of properties and intrinsic point defects in lead halide perovskites are also noted.Selected experimental approaches are suggested to better correlate property with structure of a material and help resolve the controversies.Understanding and identification of the origin of luminescent centers will help design and engineer perovskites for wide device applications.
基金supported by ITER IO, the National "973" Program of China (No. 2007ID2006)the National ITER Special Support for R&D on Science and Technology for ITER, CN Schedule Task (No. 2008GB102000)
文摘An experimental Paschen test setup has been established to analyze the quality of ITER current lead （CL） insulation and extend the research on Paschen＇s law under various conditions. Insulation problems can destroy a machine if a Paschen discharge is triggered by an insulation defect that is caused by faulty manufacturing, electromagnetic force, and thermal stress load with a certain degree of vacuum helium or pipe leakage. The results show that the CL insulation mock-up worked well under normal temperature and pressure. Besides, the mock-up also worked well in helium conditions and at 80 K temperature at different pressures. One area of CL insulation was severely destroyed when the 80 K test was conducted after 5 thermal cycles, resulting in Paschen discharge phenomenon. The breakdown voltage is maintained at a relatively low level under different pressure conditions; the change of breakdown voltage was mainly due to the change of pressure, and such change was in line with the Paschen law.
文摘This Paper reports a new system for preparation of lead titanate powders by the Sol Gel method. In this system, basic lead lactate, (CH 3CHOHCOO) 2Pb, is used as the lead precursor instead of the widely used Pb(OOCCH 3) 2·3H 2O and titanium tetrabutoxide monomer. This new system simplifies the chemical processing of precursor solutions of lead titanate, increases their stability in air, and offers good control Pb(Ti stoichiometry. The xerogel, obtained from the precursor solution by aging at low temperature, is found to have a higer inorganic content. Gel to ceramic conversion is achieved by calcining the xerogel from 400℃ to 800℃. The phase purity, particle size, morphology, compositional homogeneity of the gel derived powders are examined by XRD. TEM.IR and the slow reflection spectrum of partides are measured.
文摘Some heart diseases need long-term monitoring to diagnose. In this paper, we present a wearable single lead ECG monitoring device with low power consumption based on MSP430 and single-lead ECG front-end AD8232, which could acquire and store patient’s ECG data for 7 days continuously. This device is available for long-term wearing with a small volume. Also, it could detect user’s motion status with an acceleration sensor and supports Bluetooth 4.0 protocol. So it could be expanded to be a dynamic heart rate monitor and/or sleep quality monitor combined with smart phone. The device has huge potential of application for health care of human daily life.
文摘采用固含量及pH值、SEM、IR、TGA/DSC等分析方法对两种木素进行理化性能分析。对分别采用这两种木素的12 V 70 Ah样品电池进行低温放电性能、充电接受能力和循环寿命性能验证。结果发现:两种木素在官能团及热重分析的第1个吸热峰存在差异。木素B对铅酸蓄电池的低温放电性能、25℃下17.5%DoD循环寿命和60℃下17.5%DoD循环寿命更有利。通过综合分析木素B的理化性能和电化学性能得出了木素B的最佳添加量。
