Analysis of running child pedestrians impacted by a vehicle using rigid-body models and optimization techniques

Lack of information from vehicle-to-child pedestrian impacts provides considerable challenges when developing vehicle countermeasures for the pediatric population. Crash reconstructions of real-world incidents provide useful information about the vehicle damage and injury outcome but do not permit definitive and quantitative measures of the impact severity given the high level of uncertainty in the initial conditions of the pedestrian and the vehicle prior the impact. This paper develops an advanced methodology for reconstructing child pedestrian–vehicle impacts that combines the crash data with multi-body simulations and optimization techniques for identifying the pedestrian posture and vehicle speed prior to impact. For the child pedestrian posture, a continuous sequence of the running gait was developed based on the literature data and simulations. Using vehicle damage information from an actual child pedestrian crash, an objective function was developed that minimized the difference between vehicle and pedestrian contact points for the simulated child postures, pedestrian, and vehicle speeds. Simulated annealing and genetic optimization algorithms were used to identify sets of potential solutions for the pedestrian and vehicle initial conditions. Local minimums were observed for several response surfaces of the objective function which shows the non-convex nature of the crash reconstruction optimization problem with the chosen objective function. Based on the results of the real-world reconstruction, this study indicates that numerical simulations coupled with heuristic optimization algorithms can be used to reconstruct child pedestrian and vehicle pre-impact conditions.     

Possible involvement of the glycocalyx in the ichthyotoxicity of Chattonella marina (Raphidophyceae): immunological approach using antiserum against cell surface structures of the flagellate

Although the ichthyotoxic mechanism of Chattonella marina is still unknown, several lines of evidence suggest that the reactive oxygen species (ROS), such as superoxide anion (O₂^-), hydrogen peroxide (H₂O₂)_, and hydroxyl radical (·OH), produced by C. marina are involved in the mortality of fish exposed to this flagellate. Recently, we found that the cell-free supernatant prepared from C. marina, which is considered to contain the glycocalyx, showed NADPH-dependent O₂^- generation. In this study, we prepared antiserum against the crude glycocalyx of C. marina. Using indirect immunofluorescence, it was confirmed that the antiserum specifically reacted with C. marina cells. In addition to C. marina, the antiserum also reacted with other raphidophycean flagellates such as Heterosigma akashiwo, Olisthodiscus luteus, and Fibrocapsa japonica, whereas no reactivity was observed against six other flagellate species tested. These results suggest that raphidophycean flagellates have common epitopes recognized by the antiserum. Interestingly, immunohistochemical analysis of paraformaldehyde-fixed gill lamellae from yellowtail exposed to C. marina revealed that the antiserum stained the surface of gill lamellae, while no such staining pattern was observed in control gill lamellae. These results suggest that the glycocalyx may be discharged when C. marina cells are inhaled into the fishes' mouths and then come into contact with the gill surface. Based on the present results, together with our previous findings, we propose that continuous accumulation of the discharged glycocalyx on the gill surface occurs during C. marina exposure, which may be responsible for the ROS-mediated severe gill tissue damage leading to fish death.     

α1-Microglobulin levels and correlation with cadmium and other metals in urine of non-smoking women among general populations in Japan

The present study was initiated to examine urinary α₁-microglobulin (α₁-MG-U) levels among non-smoking women in the general population in Japan. A previously established database on spot urine samples from adult woman volunteers in 10 non-polluted areas all over Japan was re-examined. The data examined were on α₁-MG-U, cadmium, calcium, magnesium and zinc levels in urine (Cd-U, Ca-U, Mg-U and Zn-U, respectively), urinary creatinine (CR or cr), urine specific gravity (SG or sg), smoking habits and age. Thus, 8975 never-smoking women were selected for statistical analyses. The grand geometric mean (GM) for α₁-MG-U among the population was 2.1?mg/L or 2.5?mg/g?cr, depending on the correction for urine density. It was 1.1?µg/L or 1.3?µg/g?cr for GM Cd-U. The inter-area difference in α₁-MG-U was <1.5?mg/g?cr or <0.7?mg/L; the area with the highest or lowest GM Cd-U was not always highest or lowest in GM α₁-MG-U. The correlation coefficient (0.53) between log?Cd-U and log?α₁-MG-U (both without urine density correction) became substantially smaller when the analyte levels were corrected for CR (0.25) or SG (0.26). In multiple regression analysis, the power of influence of the five independent variables (log?Cd-U, Ca-U, Mg-U, Zn-U and age) in combination was small (R ²?≦?0.13). In contrast, logistic regression analysis suggested that α₁-MG-U might be elevated as a function of an increase in Cd-U, depending on the cut-off values. Discussion was made on dose (Cd-U_cr) and response (α₁-MG-U_cr) relationship based on information available in literatures to show that the increment in α₁-MG-U_cr per Cd-U_cr was much greater when Cd-U_cr was large, e.g., in excess of 10?µg/g?cr.     

乳酸和复合脂肪酸抑制奶牛对环境污染的效果分析

将20头荷斯坦产奶奶牛随机分为对照组和试验Ⅰ～Ⅲ组,对照组饲喂全混日粮(TMR),试验Ⅰ组每头奶牛每天饲喂TMR加150.0 g复合脂肪酸,试验Ⅱ组每头奶牛每天饲喂TMR加150.0 g乳酸,试验Ⅲ组每头奶牛每天饲喂TMR加150.0 g复合脂肪酸/乳酸(质量比为1∶1),分析探讨了复合脂肪酸和乳酸对奶牛粪尿、氮、总磷排泄量和CH4释放量的影响.结果表明,相比对照组,试验Ⅲ组1头奶牛1年CH4释放量减少30.64 kg,粪尿、氮、总磷排泄量分别减少1.43 t、28.32 kg和2.36 kg,标准乳(FCM)提高3.28%.在奶牛饲料中添加乳酸和复合脂肪酸的混合酸,能有效抑制奶牛对土壤、水体及空气的污染,显著提高奶牛的生态效益和经济效益.     

Lectin-induced enhancement of superoxide anion production by red tide phytoplankton

Chattonella marina, a raphidophycean flagellate, is a highly toxic red tide phytoplankton which causes severe damage to fish farming. Recent studies demonstrated that Chattonella spp. continuously release superoxide anions (O₂ ⁻) while they are living. Heterosigma akashiwo, another raphidophycean flagellate, also produces O₂ ⁻. In the present study, we found that lectins such as concanavalin A (Con A), wheat germ agglutinin (WGA), and castor bean hemagglutinin (CBH) stimulated  C. marina and H. akashiwo to generate enhanced amounts of O₂ ⁻ in a concentration-dependent manner. The lectin-specific sugars potently inhibited the lectin-induced increase of O₂ ⁻ production, suggesting that the effects of lectins are mediated mainly through the interaction of these lectins with carbohydrate moiety present on the flagellate cell surface. In contrast to the potent ability of native Con A (tetravalent), succinylated Con A (divalent) showed only a slight stimulative effect on these flagellates. O₂ ⁻ production was totally inhibited by treatment with proteinase K for 30 min, without affecting the viabilities of flagellates. These results suggest that cell-surface redox enzymes may be involved in O₂ ⁻ production, and such enzymes are responsible for the lectin-stimulation. Received: 21 August 1997 / Accepted: 8 January 1998     

Separation of plastic mixtures using liquid-fluidized bed technology

Separation of heavier-than-water plastic mixtures had been investigated via the fluidization of their packed beds induced by an upward flow of water. The samples examined were resin pellets and crushed plastic products including PVC, PET and PBT. On the onset of a flow, a mixed bed was swelled to the state of fluidization and separated into layers of respective resins depending on their density. The effects of the flow rate, an amount of the samples and their density difference were examined on the separation of resin pellets. Under an appropriate condition, the process was completed within a few minutes, and satisfactory separation was attained when the density difference of the samples exceeded 0.05 g cm-3. By using a column equipped with several sample outlets sorted resins could be recovered with their purity intact by withdrawing each layer successively from above through a suitable outlet. Multi-stage separation was also found to be effective in treating close-density samples. Compared with uniform-sized resin pellets, size distribution of crushed plastic samples deteriorated the separation to some extent.     

Multivariate analyses of the effect of an urban wastewater treatment plant on spatial and temporal variation of water quality and nutrient distribution of a tropical mid-order river

Freshwater resources are increasingly scarce due to human activities, and the understanding of water quality variations at different spatial and temporal scales is necessary for adequate management. Here, we analyze the hypotheses that (1) the presence of a wastewater treatment plant (WWTP) and (2) a polluted tributary that drains downstream from the WWTP change the spatial patterns of physicochemical variables (pH, turbidity, dissolved oxygen, and electrical conductivity) and nutrient concentrations (reactive soluble phosphorus, total phosphorus, nitrogen series, total nitrogen, and total dissolved carbon) along a mid-order river in SE Brazil and that these effects depend on rainfall regime. Six study sites were sampled along almost 4 years to evaluate the impacts of human activities, including sites upstream (1–3) and downstream (5–6) from the WWTP. The impacts were observed presenting an increasing trend from the source (site 1) towards Água Quente stream (site 4, the polluted tributary), with signs of attenuation at site 5 (downstream from both WWTP and site 4) and the river mouth (site 6). Input of nutrients by rural and urban runoff was observed mainly at sites 2 and 3, respectively. At sites 4 and 5, the inputs of both untreated and treated wastewaters increased nutrient concentrations and changed physicochemical variables, with significant impacts to Monjolinho River. Seasonal variations in the measured values were also observed, in agreement with the pluviometric indexes of the region. Univariate analyses suggested no effect of the WWTP for most variables, with continued impacts at sites downstream, but non-parametric multivariate analysis indicated that these sites were recovering to chemical characteristics similar to upstream sites, apparently due to autodepuration. Therefore, multivariate methods that allow rigorous tests of multifactor hypotheses can greatly contribute to determine effects of both point and non-point sources in river systems, thus contributing to freshwater monitoring and management.     

Variation in lipid classes during the molting cycle of the prawn Penaeus japonicus

The variation in the concentration and fatty acid composition of lipid classes during the molting cycle of the prawn Penaeus japonicus was investigated. The lipid concentration of the whole body reached a maximum at mid-premolt (Stage D₂) and then decreased to low level at late premolt (Stage D_3–4). The accumulation of lipids during the premolt period seemed to be attributable to the increase of both polar and neutral lipids. The increase of neutral lipids at Stage D₂ was derived from not only triglycerides but also free sterols and free fatty acids. Regarding the fatty acid composition of every lipid class, a marked variation occurred mainly at the intermolt (Stage C). In this stage, the polar lipids were rich in monoenoic acids such as 18:1 and poor in polyenoic acids such as 20:53 and 22:63. The triglycerides were rich in polyenoic acids at Stage C, but poor in monoenoic acids such as 16:1 and 18:1. The steryl esters contained large amounts of saturated acids such as 16:0 and 18:0 throughout the molting cycle, however the level of polyenoic acids increased at Stage C.     

Studies on automated survey system of environmental chemicals by gas chromatography-mass spectrometry-computer II. Three dimensional mass chromatography

A three dimensional mass chromatography (TDMC), which is the extended method of mass chromatography, has been developed for the analysis of environmental chemicals. A considerable performance was suggested by the combination of TDMC to gas chromatography-mass spectrometry-computer system.     

Evaporation characteristics of multi-component liquid

Evaporation rate of multi-component liquid such as motor gasoline is expected to change greatly with progress of evaporation because its composition changes. Therefore it is difficult to predict accurately amount of generated combustible vapor in the case that a multi-component liquid is spilt on a floor. Then, we assumed an evaporation model that composition of the vapor obeys the Raoult's law which considers the activity coefficient. Using the model, we calculated the vapor composition, the vapor pressure and the evaporation rate of the liquid. Then, comparison was done between the calculated values and the measured values obtained in this study. “Weight loss fraction” was used as a parameter signifying the progress of evaporation. The variations of the evaporation property were accurately predicted by the model. We derived a prediction model of the amount of generated combustible vapor from the relation between weight loss fraction and evaporation rate. It was found that the amount of generated vapor was expressed as a logarithmic function of time in case of a five-component liquid. Furthermore, we showed that the predicted flash point of a liquid using the composition obtained from the model was in good agreement with an experimental result.