Lower extremity injuries in children seated in forward facing child restraint systems

OBJECTIVE: The lower extremity is among the most frequently injured body regions for children restrained by forward facing child restraint systems (FFCRS), accounting for 28% of their clinically significant injuries, defined as AIS 2 and greater injuries excluding concussions. Despite the prevalence of these injuries, the current U.S. Motor Vehicle Safety Standard governing FFCRS (FMVSS 213) does not provide a direct assessment of the biomechanical risk of lower extremity fracture nor do the current pediatric test devices provide adequate instrumentation to detect the risk of such injuries. Before improvements can be made to the anthropometric test devices (ATDs) or test procedures to address these limitations, understanding of the sources and mechanisms of these injuries is necessary. Therefore, the objective of this study was to document location, source, and crash circumstances of lower extremity injuries in children seated in FFCRS. METHODS: Utilizing two sources of data, PCPS and CIREN, 20 in-depth investigations of crashes involving children seated in FFCRS with lower extremity injuries were reviewed to determine the nature of the injuries and the circumstances under which they occurred. RESULTS: Injuries below the knee were the most common, particularly to the tibia/fibula, and they most often occurred due to interaction with the vehicle seatback in front of the child's seating position. These injuries were sustained most commonly in frontal impacts although interaction with the seatback also occurred in other crash types. This interaction with the seatback was exacerbated by possible contributing factors such as intrusion of the front seatback into the child's occupant space or FFCRS misuse resulting in increased excursion of the child during impact. CONCLUSIONS: This review of cases of children in FFCRS with AIS 2 and greater lower extremity injury points to the role of the seatback in the occurrence of these injuries, suggesting the need to consider this interaction in the seatback design process and to adequately represent this interaction in regulatory procedures assessing the performance of child restraints.     

Impact of the toxicity of Cylindrospermopsis raciborskii (Woloszynska) Seenayya & Subba Raju on laboratory rats in vivo

In vivo laboratory studies of toxicity were performed on Wistar rats using a methanol extract produced by the natural population of Cylindrospermopsis raciborskii (abundance of 2.13 × 10⁵ trichomes mL⁻¹) collected at Aleksandrovac Lake (Serbia). HPLC analysis showed that the extract contains 6.65 μg cylindrospermopsin (CYN) mg⁻¹. The rats were killed 24 or 72 h after a single intraperitoneal injection of C. raciborskii extract in concentrations of 1500, 3000, 6000 and 12,000 μg kg⁻¹ body weight (bw) and an equivalent amount of CYN as present in the highest dose of the extract (79.80 μg CYN kg⁻¹ bw). The genotoxic effect on the livers treated with C. raciborskii was evaluated using comet assay and potential induction of oxidative stress as the toxicity mechanism associated with the presence of CYN in extract. The results from the analyses of DNA damage in the comet tail length, tail moment and percentage of DNA in the tail in the liver indicated that administration of extract and CYN present statistically significant difference when compared with the negative control group. Although an increase in the frequency of selected parameters induced by the CYN was observed in the liver, this damage was less than the damage resulting from the administration of the highest dose of extract. The changes in the biochemical parameters of the hepatic damage showed that the application of single doses of the extract and CYN did not cause serious liver damage in rats. The extract and CYN significantly increased oxidative stress in rats’ liver after a single exposure.

     

An investigation of aqueous activity coefficients at low concentrations

The activity of a chemical in solution determines its tendency to move into other media. At low concentrations (<0.01M) it is generally considered to be linearly related to concentration. A hypothetical model based on the structure of liquid water is discussed which could cause deviations from this linearity in the ppb region, a concentration much lower than that normally investigated thermodynamically, but one of great importance environmentally. Headspace experiments are reported with carbon tetrachloride and chloroform in water at concentrations down to ～10^?3 ppb but no such deviations were discerned.     

油浸变压器排油注氮装置在500kV变电站的设计与应用

在分析500kV变电站主变压器消防系统的现状,比较3类消防系统优缺点的基础上,详细论述了主变排油注氮装置的结构组成、工作原理、参数计算、控制系统设计以及需要注意的事项等,为下一步排油注氮装置的推广应用打下基础.