Prevalence and Associated Factors of Viral Hepatitis C among Burundian Population during a Screening Campaign: A Cross-Sectional Study Carried out in Burundi

Approximately 180 million people worldwide are affected by Viral hepatitis C, with 350,000 to 500,000 deaths yearly. The present study sought to investigate the prevalence and associated factors of viral hepatitis C (VHC) among the Burundian population during a screening campaign. A total of 629 participants took part in the study, and the prevalence of viral hepatitis C was (8.11%). The associated factors identified as statistically associated were medical and surgical history (P = 0.02) and ear and nose piercing (P = 0.01). 51% of the infected persons were females. The mean age for viral hepatitis C carriage was 46.13 ± 14.3 years and 10.40% of viral hepatitis C carriers were over 50 years old. We found a high viral hepatitis C prevalence in married (9.55%) and divorced (9.38%) participants. The majority of our participants were farmers (60.25%) with a prevalence of viral hepatitis C (7.92%) while 11.54% of the infected participants were not educated. In conclusion, the current study shows a high prevalence of Viral Hepatitis C infection in Burundi. Infection was more likely to occur in older, married, farmer, and illiterates. Unsafe medical and surgical interventions with traditional practitioners were significant risk factors for contracting VHC infection.

化工区土壤中挥发性卤代烃分析方法的建立及应用

为提供一种简单、快捷测定化工区土壤中挥发性卤代烃(VHCs)的方法,对顶空/气相色谱-质谱法进行研究。分别对该法的主要影响因素和条件进行优化选择,通过加标回收率对结果进行评价,确定最佳测定条件。同时对该方法的精密度、准确度、检出限进行验证,完成方法验证。最后对哈尔滨市某化工区土壤样品中VHCs进行分析。结果表明,该方法简单、准确、灵敏度高,对化工区土壤监测具有较强的实用性。

不同水体中挥发性卤代烃的对比

建立了吹扫捕集与气相色谱联用技术结合电子捕获检测器分析水体中多种挥发性卤代烃的方法.定量测定了淮安市自来水、古黄河水、运河、内运河及池塘水中的挥发性卤代烃并进行了对比.结果表明,自来水中主要含有氯仿、三氯乙烯、二溴一氯甲烷等,而自来水水源古黄河水中这三种卤代烃的含量极低.运河和内运河中四氯化碳的含量偏高,而且含有少量四氯乙烯.池塘水与古黄河水水质相近.

石家庄市环境空气中挥发性卤代烃污染水平及健康风险评估

基于石家庄市区2019~2021年三年的挥发性有机物(VOCs)在线监测数据,分析其中挥发性卤代烃(VHCs)的组成、污染水平并进行健康风险评估。结果表明,近三年石家庄市区环境空气中共检出35种VHCs单体化合物,其中26种氯代烃,5种溴代烃和4种氟氯烃,分属20种卤代烷烃,9种卤代烯烃和6种卤代芳香烃。VHCs年均浓度为45.84μg/m^(3),季均浓度分别为春季11.71μg/m^(3)、夏季73.67μg/m^(3)、秋季44.79μg/m^(3)、冬季54.14μg/m^(3)。健康风险评估表明,VHCs单体对人体的非致癌风险HQ值为0.001~0.905,均在安全范围内;致癌风险R值为0.016×10^(-6)~46.013×10^(-6),有9种VHCs单体致癌风险为不可接受。从VHCs单体化合物的污染贡献率角度分析,优先控制的前五类化合物为顺式-1,2-二氯乙烯、氯乙烯、1,1,1-三氯乙烷、氟里昂-11(三氯一氟甲烷)、反式-1,3-二氯丙烯;从健康风险角度,综合考虑HQ值和R值,优先控制的污染物为三氯甲烷、1,2-二氯丙烷、1,1,2,2-四氯乙烷和1,2-二氯乙烷。优先控制的污染物多属于氯代烷烃,需要进一步研究其主要来源并制定相应的治理及减排措施。

郑州市环境空气中挥发性卤代烃污染特征与健康风险评价

用苏玛罐采样、气相色谱/质谱法分析,研究郑州市环境空气中挥发性卤代烃(VHCs)的污染特征并对其健康风险进行评价。结果显示,郑州市环境空气中共定性检出43种VHCs,其中卤代烷烃28种,卤代烯烃9种,卤代芳香烃6种,卤代烷烃、卤代烯烃、卤代芳香烃的年均质量浓度分别为67.40、34.70、20.30μg/m^3,郑州市各功能区环境空气中VHCs化合物种类稍有差异,背景点VHCs浓度与其他功能区并无显著差异,说明VHCs污染呈现区域性特征;垂直方向上,卤代烷烃浓度随高度呈先降后升趋势,卤代烯烃和卤代芳香烃浓度随高度呈先升后降趋势。健康风险评价结果显示,VHCs单体化合物对人体的非致癌风险均在安全范围内,而总风险超出了安全范围,氯乙烯、三氯乙烯、四氯化碳、氯仿、1,2-二溴乙烷、1,2-二氯乙烷和1,1,2-三氯乙烷的致癌风险超出美国环境保护署规定的可接受值;致癌风险合计为5.32×10^(-4),说明长期暴露于环境空气中对人群健康具有一定危害。

Periodic Motion Planning and Control for Double Rotary Pendulum via Virtual Holonomic Constraints

Periodic motion planning for an under-actuated system is rather difficult due to differential dynamic constraints imposed by passive dynamics, and it becomes more difficult for a system with higher underactuation degree, that is with a higher difference between the number of degrees of freedom and the number of independent control inputs. However, from another point of view, these constraints also mean some relation between state variables and could be used in the motion planning.We consider a double rotary pendulum, which has an underactuation degree 2. A novel periodic motion planning is presented based on an optimization search. A necessary condition for existence of the whole periodic trajectory is given because of the higher underactuation degree of the system. Moreover this condition is given to make virtual holonomic constraint(VHC) based control design feasible. Therefore, an initial guess for the optimization of planning a feasible periodic motion is based on this necessary condition. Then, VHCs are used for the system transformation and transverse linearization is used to design a static state feedback controller with periodic matrix function gain. The controller gain is found through another optimization procedure. The effectiveness of initial guess and performance of the closed-loop system are illustrated through numerical simulations.

聚乙烯微塑料对海洋微藻生长和卤代烃释放的影响

挥发性卤代烃(VHCs)是一类重要的痕量温室气体和臭氧破坏物质,在全球气候变化中发挥重要作用.微藻释放VHCs受海洋环境因素的影响.微塑料作为海洋中一种重要新型污染物其对海洋微藻释放VHCs的影响研究比较少见.基于小新月菱形藻(Nitzschia closterium f.minutissima)和东海原甲藻(Prorocentrum donghaiense)的室内单种培养实验,通过测定其藻细胞密度、最大光量子效率(F_(v)/F_(m))、活性氧(ROS)和VHCs浓度,研究聚乙烯(PE)微塑料长期暴露对小新月菱形藻和东海原甲藻生长和VHCs释放的影响.结果表明,PE微塑料胁迫对小新月菱形藻生长主要表现抑制作用,而对东海原甲藻生长表现出促进作用.50μm的PE微塑料的添加对小新月菱形藻和东海原甲藻的光合作用起到遮蔽作用,导致二者的F_(v)/F_(m)受到抑制,且其对东海原甲藻的抑制作用更显著.与对照组相比,PE微塑料胁迫刺激藻细胞的ROS产生量增加,引起小新月菱形藻和东海原甲藻的氧化应激反应,从而促进两种微藻3种溴代烃的释放.

同种带瓣主动脉和带瓣肺动脉补片在儿童复杂先心病的应用

１９８９年１１月至１９９２年７月期间，应用低温保存同种带瓣大动脉纠治儿童复杂性先心病１２例。病人年龄２～１６岁（７．２±３．７岁），体重８～３１．５ｋｇ（１８．９±６．６ｋｇ）。诊断为法乐氏四联症（ＴＯＦ）８例，其中伴肺动脉瓣闭锁３例；冠状动脉畸形１例；严重肺动脉发育不良２例；左肺动脉缺如２例。大动脉错位伴室间隔缺损和肺动脉狭窄２例；永存动脉干畸形（Ⅱ型）２例。８例应用同种带瓣管道作右室流出道与肺动脉连接，４例应用同种带瓣肺动脉片作跨瓣环右室流出道扩大术。本组死亡１例，最长随访时间３年。文中对同种带瓣管道的取材方法，保存技术及应用方法作了讨论。