Lead levels in Chromolaena odorata (Compositae) along rural and urban roads in Akwa Ibom State, Nigeria

Concentrations of lead(Pb) were determined in leaf samples of \%Chromolaena adorata\% from a rural road and an urban road in Akwa Ibom State of Nigeria in relation to vehicular traffic density. Mixed results were obtained wich no trend to indict automobile exhaust fumes. Lead was not detected in rain water from these areas and leaf lead levels seemed to relate more to soil lead concentrations. There was no significant difference in mean leaf lead levels between rural and urban leaf samples and between washed and unwashed leaf samples. It was suggested that the lack of concordance between vehicular traffic density and lead levels in leaves along the highways indicates either a low level use of tetraethyl leaded petrol or, a relatively low vehicular traffic density with lead from exhaust fumes not reaching a threshold to affect levels in plants or be detected in the atmosphere. Implications of concentrations obtained in leaves to consumers when compared with international standards were discussed.

Lead Concentration in Hong Kong Roadside Dust after Reduction of Lead Level in Petrol

Samples of roadside dust were collected from 30 sites in Hong Kong.The total concentrations of 10 metals in the samples were analyzed,and the correlation coefficients among the metal contents and the annual average daily traffic(AADT)in 1986 were determined.Pb was found to have a significant correlation(P<0.01)with AADT.No correlation was found between Al, Ba,Cd,Cr,Cu,Fe,Mn,Ni,and Zn with respect to AADT.A general decrease in the level of Pb in roadside dust in the past few years has been observed since the reduction in the level of lead in petrol.1989 Academic Press,Inc.

Umbilical Cord Blood Lead Levels in Shanghai, China

This study was designed to determine the cord blood lead (BPb) levels of babies born in one urban area of Shanghai, and to preliminarily identify the demographic, social environment and prenatal factors which have an effect on the cord BPb concentrations. From August to November 1993, umbilical cord blood samples were obtained from 605 live newborns in the Yangpu Maternal and Child Hospital. 257 samples were excluded from measurement because of clotting. In 348 cord samples, the geometric mean of cord BPb levels was 9. 2μg/dl, with a 95 % confidence interval of the mean 8. 86-9. 54 (μg/dl). 142 babies (40. 8 % ) had cord BPb levels of 10μg/dl or greater. As a result of this high percentage of newborns with BPb levels equal to or greater than 10 μg/dl, we estimate that each year in the Shanghal City about 60,000 newborns are at risk for developing neuropsychological deficiencies caused by maternal lead exposure during pregnancy. To investigate the factors affecting cord blood levels, the subjects with levels greater than the 70th percentile (10. 7μg/dl) (n = 104) and less than the 3oth percentile (7. 4μg/dl) (n = 104) were selected to compare the demographic, environ ment and prenatal medical history. Increased BPb levels at birth were associated with maternal passive smoking, a family member being occupationally exposed to lead, proximity to major traffic way, household coal combustion, neighborhood coal combustion, low level of meternal occupations, and the increasing occurrence of having the high lead foodstuff pidan (preserved duck egg) during pregnancy. We conclude that prenatal lead exposure has become an impor tant health issue for young children in Shanghai

Association between Polymorphisms of MALAT1 and Blood Lead Levels in Lead-exposed Workers

Lead,a heavy metal,which is nonessential but may be harmful to the human body,has been widely used to manufacture many products for use in the modern world.Lead-acid batteries have the advantages of low price,high safety,and advanced technology.

Two-echelon inventory model with service level constraint and controllable lead time sensitive to order quantity

The decision-making and optimization of two-echelon inventory coordination were analyzed with service level constraint and controllable lead time sensitive to order quantity.First,the basic model of this problem was established and based on relevant analysis,the original model could be transformed by minimax method.Then,the optimal order quantity and production quantity influenced by service level constraint were analyzed and the boundary of optimal order quantity and production quantity was given.According to this boundary,the effective method and tactics were put forward to solve the transformed model.In case analysis,the optimal expected total cost of two-echelon inventory can be obtained and it was analyzed how service level constraint and safety factor influence the optimal expected total cost of two-echelon inventory.The results show that the optimal expected total cost of two-echelon inventory is constrained by the higher constraint between service level constraint and safety factor.

A Systematic Assessment of Blood Lead Level in Children and Associated Risk Factors in China

In this study, we searched multiple databases for all relevant original articles (1996-2013). To investigate blood lead levels (BLL) and possible risk factors for lead exposure among children in China A total of 388 articles met our inclusion criteria. The overall geometric mean (GM) BLL was 71 μg/L, and the prevalence of elevated BLL (EBLL, defined as BLL &ge;100 μg/L) was 18.48% among children. The prevalence of EBLL remained significantly higher among boys. In children less than 6 years of age, there were significantly increasing trends in both BLL and prevalence of EBLL in an age-dependent manner. The ban on leaded gasoline significantly reduced the BLL as well as EBLL prevalence; however, children whose parents had lower educational levels or were exposed to lead in the workplace had a higher EBLL prevalence. Despite its decline over time, the average BLL among children in China remains higher than the average level most recently reported in the United States. Childhood lead poisoning remains a public health problem in China.

Blood Lead Levels During Pregnancy and Its Influencing Factors in Nanjing,China

Objective To investigate the blood lead levels （BLLs） in the duration of pregnancy and 6-12 weeks after delivery, and analyze the influencing factors of BLLs in healthy pregnant women. Methods Pregnant women were recruited from September 2009 to February 2010 at the prenatal clinic in Nanjing Maternity and Child Health Care Hospital. Altogether 174 healthy pregnant women without pregnant or obstetric complications or abnormal pregnancy outcomes were enrolled as the gravida group, and 120 healthy non-pregnant women as the control group. BLLs during pregnancy were determined by flame atomic absorption spectroscopy. Results BLLs in all the three pregnancy trimesters and postpartum were 59.8±24.3, 55.4±20.1, 55.9±19.7, and 67.6±17.4 μ/L, respectively, and the mean BLL in control group was 67.5±21.3 μg/L. BLLs during all the three trimesters were lower in the gravida group than in the control group （P=0.043, 0.021, and 0.028）. Furthermore, occupations, nutrients supplementation, and time of house/apartment painted were associated with BLLs in pregnant women. Lead-related occupations, cosmetics use, and living in a house painted less than 1 year before are risk factors of high BLLs among pregnant women, while calcium, iron, zinc, and milk supplements are protective factors. Conclusion Supplementing calcium, iron, zinc, and milk, or avoiding contact with risk factors may help people, especially pregnant women, to reduce lead exposure.

Economic Responsibility Audit of Leading Cadres of the Party and Government at the Grassroots Level-Existing Problems and Countermeasures

Economic responsibility audit is an important part of the socialist audit supervision system with Chinese characteristics.It is an important responsibility of audit institutions at all levels to carry out economic responsibility audit.This article conducts a comprehensive and profound analysis of the problems existing in the current grassroots economic responsibility audit work.In addition,countermeasures and suggestions are proposed in this article,which are of positive significance to promote the economic responsibility audit work of leading cadres.

Lead poisoning due to geophagia: The consumption of miniature pottery

Geophagia (the pica of pottery, clay, earth, or dirt) is practiced before and during pregnancy in several countries, including Mexico, Turkey, Australia, and some African countries, and has been linked with cultural fertility beliefs and the satisfaction of cravings. Unfortunately, consumption of contaminated pottery can represent a source of lead exposure. Concerns regarding ingested pottery are two-fold;first, that people consuming these pots might be exposed to high concentrations of lead, and, second, that ingestion of these pots by pregnant women could result in elevated in utero lead exposure for the fetus. Very few published articles exist on this topic. In an effort to investigate “pot eating”, this study aims to summarize published case studies on lead poisonings resulting from consumption of contaminated pottery. Additionally, several pottery items that are sold for the purpose of consumption were located and analyzed. This paper investigates the risk that “pot eating” poses by reviewing the literature, examining case studies, and analyzing the availability and lead concentration of edible pottery. Preliminary research indicates that although it is not common, “pot eating” can represent a high-risk lead exposure for pregnant women and their fetuses.

Evaluation of Lead Exposure by Hand Wipes: A Review of the Effectiveness of Personal Hygiene on Industrial Sites

To evaluate the effectiveness of personal hygiene (handwashing) amongst workers at industrial sites to remove lead from their hands, a retrospective analysis of hand wipe samples was conducted using data collected by two contractors from two bridge painting projects for total lead using method ASTM E-1979-17/EPA SW846 7000B. Exposures resulted from the removal of lead-based paint from the structure and trace elements of lead found in the abrasive blast media. In total, six work tasks were evaluated and sixty unique hand wipe samples were evaluated. Thirty samples were collected during the worker’s lunch break, after they had reportedly washed their hands with a further 30 collected at the end of the workday following the same protocol. To be included in this evaluation, the contractors were required to follow NIOSH Method 9105 (Lead in Dust Wipes-Dermal Surfaces) with subsequent analysis of samples for total lead by an American Industrial Hygiene Association (AIHA) accredited laboratory. All 60 samples contained detectable lead. The lead exposures ranged from 19.5 μg to 3420 μg. The geometric mean for the samples collected was 337 μg. These results indicate that current personal hygiene practices at the evaluated sites are not effective at removing lead from worker’s hands during and after the workday. They also suggest that the residual lead measured on the workers’ hands, at the end of the shift, is likely contributing to the elevated blood lead levels in this population.

Lead Pollution Research of Resident Children around Some Industrial Park

Lead is an important toxic heavy metal among environment pollution. Some industrial parks were founded in 2005 including non-ferrous metal processing and smelting plants. In order to identify the consequence of lead pollution on children around the industry park, blood samples of neighboring children were collected and analyzed in laboratory. The results showed that the involved children have suffered serious harms from Pb pollution. Almost 75% of the children＇s blood lead levels （BLLs） exceeded the limit of normal blood lead. Worse still, 26.17% of them were at the level of Moderate lead poisoning. The group aged 0-7 showed more susceptibility to Pb than that aged 8-14. Only 19.05% of the children aged 0-7 were at the level of normal blood lead, compared with 45.45% in the group aged 8-14. There was no significant difference between the values of blood lead concentration for male and female or among different age groups. Some approaches, which include controlling the Pb pollution from the industry park and safeguarding the residents, esp. the children were suggested.

Association of Bone Turnover Levels with MTHFR Gene Polymorphisms among Pregnant Women in Wuhan, China

Pregnancy is a critical stimulator of bone mineral resorption. We used to find the MTHFR gene polymorphisms are related with blood lead levels among pregnant women. Pregnancy-stimulated bone turnover may be associated with MTHFR gene polymorphisms too. In this article, we aimed to determine the relationship between MTHFR gene polymorphisms and bone turnover rates among the pregnant women. The participants including pregnant and non-pregnant women were selected and recruited during their routine prenatal or physical examination from July to October in 2012. A total of 1000 participants, including 250 pregnant women in the first, second, and third trimesters and 250 non-pregnant women, were enrolled in the study. Finally, after excluding 27 participants unable to provide blood samples, 973 eligible participants （i.e., 234, 249, and 248 pregnant women in the first, second, and third trimesters, respectively, and 242 non-pregnant women） were included in the research. The MTHFR gene 1298CC homozygote carriers were more susceptible to yield higher plasma homocysteine levels than the 1298AA/AC carriers, with standardized coefficients of 0.086 （P〈0.05） and 0.104 （P〈0.01） of all the participants and the pregnant women, respectively. The MTHFR gene 1793AA homozygote carriers more likely showed higher plasma osteocalcin levels （standardized β=0.091, P〈0.01） than the 1793GG/GA carriers among all the subjects. Plasma homocysteine levels were positively correlated with blood lead levels among the participants and the pregnant women with standardized coefficients of 0.320 （P〈0.01） and 0.179 （P〈0.01）, respectively. Plasma osteocalcin levels were positively associated with blood lead levels among pregnant and non-pregnant women with standardized coefficients of 0.084 （P〈0.05） and 0.125 （P〈0.01）, respectively. In conclusion, homocysteine and osteocalcin contents in plasma are associated with the MTHFR gene A1298C polymorphism and blood lead levels among pregnant women. The MTHFR gene A1298C polymorphism-related homocysteine is a possible risk factor for increased blood lead levels among Chinese women.

Origin of Luminescent Centers and Edge States in Low-Dimensional Lead Halide Perovskites:Controversies,Challenges and Instructive Approaches

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.

Evaluation of the Effectiveness of Hygenall^©Leadoff^TMFoaming Soap in Reducing Lead on Workers’ Hands and the Uptake of Lead on Bridge Painting Projects

Although considerable research has been conducted regarding airborne lead exposures during lead paint removal, little data has been collected measuring the lead concentration on workers’ hands in the construction industry. As a result, there are gaps in our understanding of the effectiveness of a standard work practice control (handwashing) in the prevention and control of elevated blood lead levels (BLLs) in the workplace. The primary objective of this study was to assess if a National Institute for Occupational Safety and Health (NIOSH) formulation intended to remove lead from skin (Hygenall© LeadoffTM Foaming Soap) is more effective than a commonly used soap in the industrial painting industry (Zep Cherry Bomb Soap) in reducing the concentration of lead on workers’ hands after exposure. A secondary aim was to assess if using LeadoffTM Foaming Soap during handwashing reduces worker uptake of lead on bridge painting projects. We evaluated hand wipe, air sample and blood lead level data collected by two industrial bridge painting contractors. Airborne exposures ranged from 350 μg/m3 to 19,700 μg/m3. The geometric mean lead concentration remaining on workers’ hands after using Zep Cherry Bomb Soap was 77 μg per hand wipe compared with 61 μg per hand wipe after use of LeadoffTM Foaming Soap for all work classifications. The geometric lead concentration on workers’ hands decreased by 16 μg/hand wipe for all work classifications combined after using LeadoffTM Foaming Soap—a decrease of 21%. The use of Hygenall LeadoffTM Foaming Soap reduced the maximum lead concentration on workers’ hands by 85%. The geometric mean BLL for all work classifications was 12.1 μg/dl before the use of LeadoffTM. After two months of airborne exposure and use of LeadoffTM Foaming Soap at breaks and at the end of the workday, the geometric mean BLL for all work classifications increased to 18.1 μg/dl. Worker BLLs increased despite the reduction in the concentration of lead measured on workers’ hands—most likely a result of ineffective inhalation exposure controls. We found that the LeadoffTM Foaming Soap was more effective in removing lead from workers’ hands than Zep Cherry Bomb.

The Design Method of Leading Space of New Chinese Style Residential Area

In recent years,the new Chinese architectural style has become a new school of contemporary creation,which is reflected in many design types.This study aimed at all kinds of problems encountered in the creation of the new Chinese style residential area’s leading space and made a research and summary on the design type and construction strategy of the new Chinese style residential area’s leading space through combing and analyzing the relevant theories and cases,in order to provide some inspiration and reference for the design and research in the future.

中国龙头科技企业技术创新能力驱动路径研究——基于fsQCA研究方法

为推动中国科技企业高质量发展,提升科技企业创新能力,对中国龙头科技企业技术创新能力进行深入探究。基于企业内部研发资金投入、研发人员投入和税收优惠、地方补贴及行业技术5个前因条件,阐述其对中国龙头科技企业技术创新能力的影响。采用模糊集定性比较分析法对26家中国不同行业上市龙头科技企业进行分析,构建前因条件对创新能力的影响框架,结果发现:从整体看,企业研发投入、地方政府补贴以及行业技术通过不同条件组态影响龙头科技企业创新能力;从企业资源看,相较于研发资金,研发人员对龙头科技企业创新能力的影响更加显著;从外部环境看,市场和政府采用优势互补方式驱动龙头科技企业创新,且市场行业技术对企业创新的影响更显著,地方政府补贴对企业创新发挥显著激励作用。

LAWS GOVERNING THE DISTRIBUTION OF LEAD-ZINC DEPOSITS IN CHINA

An attempt is made in this paper to describe the following laws governing the distribution of lead-zinc deposits in China: spatial distribution laws, temporal distribution laws, deep level control laws, and deposits association and zoning laws.

中国县级领导班子群体特征研究——基于东西部比较分析

面对东西部发展存在的巨大差距,西部地区必须全面提升发展质量,而这离不开作为地区发展“领头羊”的领导班子的引领和推动。现有文献对于领导干部群体特征以及配置结构进行了深入的归纳和探讨,但也有必要比较区域间领导干部整体水平的差异并分析其潜在原因,据此对症下药。比较东西部领导班子的群体特征,对于西部地区领导干部的培养、选拔有一定参考价值。论文运用高层梯队理论,采用分层抽样的方法,在广东省、天津市、陕西省、重庆市获得562名县级党政领导班子的履历信息,从人口统计学特征、教育背景、职业发展经历三个维度进行分析,对比研究东西部地区县级党政领导班子群体特征的共性和差异。本研究利用EXCEL对县级领导班子特征各个指标的变量进行统计分析,通过均值、标准差等数据展示变量的分布结构和特征;利用SPSS21.0对东西部县级领导班子的差异性特征进行分组,通过t检验、卡方检验等呈现数据间的差异性。研究表明,东西部党政领导班子在性别、民族、政治面貌、教育背景等方面呈现出相似的特征,但在籍贯来源、年龄、任职经历、晋升路径等方面呈现出显著差异,西部地区县级领导班子年龄分布呈现“两头多,中间少”、籍贯结构“本地多,外地少”、教育背景“偏人文,轻理工”、“任职经历单一,工作经验同质性高”、自下而上晋升比例更低等明显特征。针对分析结果,建议西部县级党政领导班子要着重加强领导班子协同效能建设、优化领导班子干部队伍结构、完善现代干部任用选拔机制,以及进一步强化领导干部的交流制度。

地缘文化视角下非遗嵌入高校设计教学的路径研究

非遗作为中华文明的重要组成部分,其地缘文化背景、实践性和创新性为设计教育提供了新的视角、思路、教学资源和教学方法。通过运用嵌入性理论,深挖非遗本土化特色,有机融入设计教学结构,有助于培养学生的文化自信、创新思维和实践能力,满足社会和行业发展的需求。非遗的跨学科特性和实践创新价值为设计教育提供新的教学资源和方法,为文化传承与创新注入新的活力,为地方经济的发展和文化传承创新提供支持。本文在推动高校课堂精细型教学与田野粗放型教学的互补,建立知行合一的设计教学路径,为地方高校设计教学与人才培养提供参考。

分子水平上的虚拟仿真实验之思政元素的挖掘与提炼——以“高分子的构象、形态及尺寸的模拟与计算”项目为例

高分子的构象、形态及尺寸的模拟与计算,是分子水平上的虚拟仿真实验项目,结合诺贝尔奖获得者de Gennes和P.J.Flory的理论工作、由项目组自身教研成果转化、师生合作研发而成。与小分子化合物相比,高分子的研究方法有很大的不同,特别是需要采用统计方法来描述高分子链的构象、形态,计算高分子链的平均尺寸,这是经典的物理化学方法所不能完成的。本项目从研发到教学实践、再经改进,教学内容的更新优化中,自然融入了诺贝尔奖成果、哲学思想、科学思维、学科发展史、教研成果等多个维度的思政元素。