The aim of this study was to characterize the protein expression of matrix metalloproteinase-2 (MMP-2) and -- 9 and their inhibitors (TIMP-1 and -2) in mammary tissue of dairy cows with naturally occurring chronic S. aureus intramammary infections (IMI) during active involution. Moreover, the gelatinolytic activity of MMP-2 and -9 in mammary secretions was evaluated. Cows in late lactation that were either uninfected or with chronic naturally acquired S. aureus IMI were included in this study. Protein expression of MMP-2 and -9 in mammary tissues was significantly higher in S. aureus-infected than uninfected quarters at day 14 and 21 of involution. Protein expression of TIMP-1 and -2 was significantly higher in S. aureus-infected than uninfected quarters at day 7, 14 and 21 of involution. The MMP-2/TIMP-1, MMP-2/TIMP-2, MMP-9/TIMP-1 and MMP-9/TIMP-2 ratios were significantly higher in S. aureus-infected compared with uninfected quarters at day 14 of involution. The MMP-2 activity was significantly higher in mammary secretions from S. aureus-infected compared with uninfected quarters at day 1, 2, 7 and 14 of involution. The MMP-9 activity was significantly higher in mammary secretions from infected quarters compared with uninfected quarters at day 7, 14 and 21 of involution. The increased expression of MMP-2 and -9 in mammary tissue as well as the high levels of activity observed in mammary secretion from infected quarters compared with uninfected quarters during active involution, strongly suggests that these gelatinases could contribute to degradation of mammary tissue components during chronic S. aureus IMI. The MMPs/TIMPs imbalance could lead to greater proteolysis and potentially more damage to mammary tissue in S. aureus-infected quarters.Driving automation systems (e.g., SAE Level 2) ultimately aim to enhance the comfort and safety of drivers. At present, these systems are able to control some portions of the driving task (e.g., braking, steering) for extended time periods, giving drivers the opportunity to disengage from the responsibilities associated with driving. In this study, data derived from two naturalistic driving studies involving automation-equipped vehicles were analyzed to evaluate driver behaviors with respect to driving automation system use, specifically distraction-related factors (i.e., secondary task engagement, eye-glance behavior, and drowsiness). The results indicate that when drivers had prior experience using driving automation systems, they were almost two times as likely to participate in distracted driving behaviors when the systems were active than during manual driving. Drivers with less experience and familiarity with driving automation systems were less likely to drive distracted when the systems were active; however, these drivers tended to be somewhat drowsy when driving with systems activated. The results provide important insights into different operational phases of driving automation system use (i.e., learning/unfamiliar vs experienced users), whereby experience results in overtrust and overreliance on the advanced technologies, which subsequently may negate some of the safety benefits of these systems. Thus, while the safety benefits of driving automation systems are evident, it is imperative to better understand the impact these advanced technologies may have on driver behavior and performance in order to evaluate and address any unintended consequences associated with system use.Unsignalized intersections are highly susceptible to traffic crashes compared to signalized ones. By taking into account temporal stability and unobserved heterogeneity, this study investigates the determinants of the injury severity of drivers involved in crashes at unsignalized intersections controlled by give-way (yield) signs. Mixed logit models with three approaches were employed, namely random parameters, random parameters with heterogeneity in means, and random parameters with heterogeneity in means and variances. The investigation covered four years (2015-2018) of motor vehicle crashes in South Australia, and the injury severity was categorized into no injury, minor injury, and severe injury. Log-likelihood ratio tests revealed that there is a significant temporal instability in the four years of crashes. NMS-P937 solubility dmso Thus, each year was considered separately to avoid any potential erroneous conclusions and unreliable countermeasures. The study found 28 indicator variables were temporally unstable over the four years of crashes, such as driver gender, time of the crash, rear-end involvement, sideswipes, right-angle crash type, vehicle movement at crash time, and crash time. Whereas several variables were stable over the same period, for example, crashes within metropolitan areas were temporally stable over four years, crashes in dry pavement condition were temporally stable over three consecutive years. Four factors have temporal stability over two consecutive years alcohol involvement crashes, hitting fixed objects, hitting cyclists, and crashes during winter. Overall, mixed logit models with heterogeneity in means and with/without variance performed better than the standard one. It is recommended that temporal instability be considered in order to avoid any potential inconsistent countermeasures.As the use of powered two-wheeler (PTW) becomes increasingly prevalent, PTW accidents are emerging as a major threat to the people's life and property in China. Understanding the risky behaviors, psychological failures and kinematics in vehicle-to-PTW accidents is an important first step in addressing this issue. Here 69 vehicle-to-PTW accidents captured on video from the Traffic Accident Investigation and Research in China (TAIRC) database are selected and reconstructed. All accidents are categorized into different crash scenarios using a harmonized method. Accident causations are identified from the perspectives of praxeology and psychology. Kinematics characteristics, such as impact speed and relative position, are also analyzed. The results show the crossing accident bundle is the most frequent followed by rear, oncoming and run-up accident bundles, with proportions of 43.48 %, 27.54 %, 11.59 % and 17.39 % respectively. Accident causations of different crash scenarios have great differences whether in accident responsibilities or in psychological failures.