Mother gestational exposure to organophosphorus pesticide induces neuron and glia loss in daughter adult brain

Chlorpyrifos (CPF) is a widely used organophosphorus pesticide with developmental neurotoxicity such as morphogenesis toxicity. In the present study, we assessed the effects of prenatal CPF exposure on systemic parameters and cytoarchitecture of medial prefrontal cortex (mPFC) in adulthood. Gestational dams were exposed to 5mg/kg/d of CPF during gestational days 13–17, while body weight, organ coefficient, and neuron and glia counts of offspring were determined on postnatal day 60. Our results showed that CPF treatment induced little or no effects on body weight and organ coefficients. There were also no significant pathological changes in mPFC. However, neuron and glia count analysis showed that CPF treatment reduced neuron and glia counts in anterior cingulate, prelimbic, and infralimbic areas of mPFC. The CPF react pattern was similar in both sexes, and there was no statistical difference in most of the sub-regions. Thus, our results revealed an embryonic origin brain deficit induced by gestational mother pesticide exposure.     

The role of built environment on pedestrian crash frequency

This study investigates (i) the link of land use and road design on pedestrian safety and (ii) the effect of the level of spatial aggregation on the frequency of pedestrian accidents. For this purpose, pedestrian accident frequency models were developed for New York City based on an extensive dataset collected from different sources over a period of 5 years. The assembled dataset provides a rich source of variables (land-use, demographics, transit supply, road network and travel characteristics) and two different crash frequency outcomes: total and fatal-only collision counts. Among other things, it was observed that the census tract analysis (disaggregate data) provides more insightful and consistent results than the analysis at the zip code level. The results indicate that tracts with greater fraction of industrial, commercial, and open land use types have greater likelihood for crashes while tracts with a greater fraction of residential land use have significantly lower likelihood of pedestrian crashes. Moreover, census tracts that have a greater number of schools and transit stops - which are determinants of pedestrian activity - are more likely to have greater crashes. Results also show that the likelihood of pedestrian-vehicle collision increases with the number of lanes and road width. This suggests that retrofitting or narrowing the roads could possibly reduce the risk of pedestrian crashes.     

Reliability analysis of pedestrian safety crossing in urban traffic environment

This paper describes the pedestrian safety crossing behaviour at signalized crosswalks in an urban traffic environment based on human reliability analysis. In our research, pedestrians’ waiting durations are modelled by a non-parametric and two parametric reliability models that recognize the effects of covariates. The covariates include pedestrian personal characteristics and urban traffic conditions in order to reflect the effects of human factors and internal environment comprehensively. The results indicate that most pedestrians show distinct time-dependent reliability but a few pedestrians are too impatient to wait for the lights changes.     

标贯试验N值与土体物理力学参数的相关性分析

以武汉某地铁工程为例,通过标贯试验和室内土工试验,对地基土标贯试验指标N值与土体部分物理力学参数的相关关系进行了研究,并给出了线性拟合关系式及其相关系数。结果表明:一般性黏土和老黏土的压缩模量、内聚力及内摩擦角,砂土的变形模量、承载力、内摩擦角、剪切波速及动弹模量都与标贯击数N值成正比关系;对于不同的地层类型,其拟合精度也有所区别,而对于该工程地基土,砂土的预测精度普遍高于黏土的预测精度。     

利用ATP生物发光法快速检测丽娃河中细菌总数

利用ATP生物发光法对丽娃河中细菌总数进行了快速检测。结果表明,丽娃河中细菌总数维持在0.72×106～1.2×107CFU/mL,较综合整治前的水质有了明显地改善。研究了游离ATP以及浮游生物等对发光强度的影响,发现对样品采用过滤的方法进行预处理是提高ATP生物发光法精确度的一种重要手段。     

Evidential role of municipal solid waste and liquid effluent on environment and public health

Cities in Bangladesh produce large amounts of solid waste (SW) through various human activities which severely pollutes our native environment. As a result, SW pollutes the three basic environmental elements (air, water, and soil) by increasing pathogenic microbial load, which might be hazardous to public health directly or indirectly. In this study, we conducted 30 samples (i.e., soil, water, and air) collected from areas where municipal solid wastes are dumped (Tangail Sadar Upazila, Bangladesh). All the samples were analyzed to assess bacteriological quality for presumptive viable and coliform count using different agar media. We performed serial dilution 10⁻³–10⁻¹⁰ times for soil and water samples, and the diluted samples were spread on Mac-Conkey agar and nutrient agar plates. For the air sample, the sterile media containing petri-dish was placed adjacent to the dumpsite of the municipal waste and kept for an hour. Then all the samples were incubated at 37°C overnight for total viable count (TVC) and total coliform count (TCC). Biochemical tests and PCR were performed for the identification of these microorganisms. The antibiogram study was performed to reveal their (identified bacteria) susceptibility against clinically used antibiotics according to the standard disk diffusion technique. The highest bacterial loads were found in the air: TVC 3.273 × 10³ and TCC 1.059 × 10³ CFU/plate; tube-well water: TVC 8.609 × 10³, and TCC 8.317 × 10³ CFU/mL; in surface water: TVC 6.24 × 10¹³ CFU/mL and TCC 2.2 × 10¹² CFU/mL; in soil: TVC 2.88 × 10¹¹ and TCC 1.02 × 10¹¹ CFU/g, respectively. Microbes from SW can be transmitted through air, dust particles, or flies, and here we found an average of 1120 microbes spread over 63.61 cm² area per hour. Eight bacterial isolates (Pseudomonas spp., Klebsiella spp., E. coli, Proteus spp., V. cholera, Salmonella spp., Shigella spp., and Vibrio spp.) were identified by the biochemical test. Among them, E. coli and Shigella spp. were further ensured by PCR targeting bfpA and ipaH genes. Antibiotic susceptibility test results showed that E. coli isolates were highly resistant to erythromycin (80%); Shigella spp. were resistant to nalidixic acid (90%), whereas Salmonella spp. was found resistant to kanamycin (90%). Vibrio spp. were also resistant to azithromycin (80%) and erythromycin (80%), which should be a great concern for us. A semi-structured survey revealed that 63% of respondents suffered from different clinical conditions (intestinal diseases) due to SW pollution. So, steps should be taken to improve the proper management and disposal of solid waste and liquid effluent to save our environment and public health.     

Pedestrian crossing behavior,an observational study in the city of Ushuaia,Argentina

Objectives: Pedestrian crashes are a critical problem in Latin American countries. However, little research has been published about pedestrians and even less about their behaviors in a naturalistic context. The objective of the present research was to explore risky pedestrian crossing behaviors in traffic intersections in an argentine city (Ushuaia). It is focused in different stages of the crossing process, traffic code violations, and other potentially risky behaviors such as distractions. A high frequency of risky behaviors among pedestrians was expected. Moreover, according to previous findings, it was hypothesized that men and younger pedestrians would show riskier behaviors.

Methods: Participants were 802 pedestrians (53.9% females) observed at several intersections (with and without traffic lights) in the city of Ushuaia. Behaviors were codified following a standardized observation protocol. Observers documented information on behavior previous to, during, and after crossing. Gender and age were also registered. Data were gathered through video recording. Frequency analyses of observed behaviors were conducted for the total sample, as well as by gender and by age group. A general crossing risk index was calculated to facilitate comparisons between the genders and age groups. We conducted an analysis of variance to evaluate gender and age differences for this index.

Results: A high proportion of risky behaviors were observed among pedestrians. The majority of pedestrian waited in the street (as opposed to on the sidewalk) before crossing, did not comply with traffic lights, or crossed outside the crosswalk. A large number of pedestrians were distracted while crossing. Men presented higher scores on risky behaviors than women. No differences were observed by age group.

Conclusions: The high level of risk behaviors during the different stages of street crossing is worrisome and reinforces the idea that pedestrians are responsible for many of the conflicts with motorists. Many of the risky behaviors seem to be associated with gender, which is in line with the previous literature showing more risk behaviors among men than among women. No differences were found for age group. Findings are interpreted considering some features of the Argentine road culture.     

Local vs. national: Epidemiology of pedestrian injury in a mid-Atlantic city

Objective: Understanding pedestrian injury trends at the local level is essential for program planning and allocation of funds for urban planning and improvement. Because we hypothesize that local injury trends differ from national trends in significant and meaningful ways, we investigated citywide pedestrian injury trends to assess injury risk among nationally identified risk groups, as well as identify risk groups and locations specific to Baltimore City.

Methods: Pedestrian injury data, obtained from the Baltimore City Fire Department, were gathered through emergency medical services (EMS) records collected from January 1 to December 31, 2014. Locations of pedestrian injuries were geocoded and mapped. Pearson's chi-square test of independence was used to investigate differences in injury severity level across risk groups. Pedestrian injury rates by age group, gender, and race were compared to national rates.

Results: A total of 699 pedestrians were involved in motor vehicle crashes in 2014—an average of 2 EMS transports each day. The distribution of injuries throughout the city did not coincide with population or income distributions, indicating that there was not a consistent correlation between areas of concentrated population or concentrated poverty and areas of concentrated pedestrian injury. Twenty percent (n = 138) of all injuries occurred among children age ≤14, and 22% (n = 73) of severe injuries occurred among young children. The rate of injury in this age group was 5 times the national rate (Incident Rate Ratio [IRR] = 4.81, 95% confidence interval [CI], [4.05, 5.71]). Injury rates for adults ≥65 were less than the national average.

Conclusions: As the urban landscape and associated pedestrian behavior transform, continued investigation of local pedestrian injury trends and evolving public health prevention strategies is necessary to ensure pedestrian safety.     

基于行人占据区域的泰森多边形人员密度统计方法

行人动力学的研究一直是火灾下人员疏散研究的重要内容。研究者通过大量观测和可控实验,获得行人的运动行为特征,揭示人员运动规律,但是仍然缺乏足够的定量校准的实验数据。在总结了前人对于实验中全局密度与局部密度统计方法的基础上,基于泰森多边形方法,结合人际关系距离与视野的观念,提出了一种行人占据多边形的速度密度统计方法。通过对平均密度平均速度的比较发现,方法得到的结果比传统统计方法得到的结果波动更小且更接近于连续变化、在密度低时比泰森多边形方法的结果更符合实际情况;而对于个人的速度密度散点图,结果也比泰森多边形方法的结果更为集中,尤其是除去了密度小而速度低的不合理数据点。     

3M测试片法在膜法水处理技术中的应用

采用3M测试片法测定膜法水处理系统的细菌总数,找出双膜系统的微生物污染环节,并采用正交实验筛选出适宜的杀菌剂种类、杀菌剂加入量和杀菌时间。实验结果表明：3M测试片法的测定结果数据准确可靠,且操作简便,节省时间,可以替代常规的平皿培养法用于评价膜的微生物污染情况;某炼化公司双膜系统的反渗透膜已受到微生物的污染,确定的适宜杀菌条件为杀菌剂Trsea 380、杀菌剂加入量50 mg/L、杀菌时间2.0 h,在此条件下杀菌率可达100%。