Analysis of fall kinematics and injury risks in ground impact in car-pedestrian collisions using impulse.

In vehicle-to-pedestrian collisions, pedestrian injuries occur due to contact with the car and the ground. Previous studies investigated pedestrian kinematic behavior using a parameter study or through statistical analysis although the force interaction between the pedestrian and the vehicle has not been considered. In this study, multibody analyses were conducted for vehicle-pedestrian collisions for adult and child pedestrian with various vehicle shapes. The impulse and impulse moment acting on the pedestrian from the vehicle were introduced, and the kinematic behavior, rotation and ground impact of the pedestrian model were examined. It was found that if an impulse moment acts on the pedestrian when the pedestrian re-contacts with the hood of the car, the angular velocity of the pedestrian's torso changes in the opposite direction (away from the car), and the torso angle prior to the ground contact decreases to less than 90°. This re-contact between the pedestrian and the vehicle was more likely to occur for cases where the collision involves an adult pedestrian, lower hood leading edge (HLE), longer hood length, and lower collision velocity. When the pedestrian torso angle in contact with the ground was less than 90°, the head vertical impact velocity with respect to the ground became less than 2.9 m/s which corresponds to the injury threshold of the head. This study demonstrated that pedestrian-vehicle re-contact is crucial for reducing ground injury. The vehicle shape, pedestrian size, and collision velocity can determine whether re-contact of the pedestrian with the vehicle occurs. This can then explain the factors affecting pedestrian ground impact injury (e.g., higher HLE, higher risk of ground head injury for children) that were shown in previous studies. A strategy to mitigate ground injury is to apply enough impulse moment onto the pedestrian's upper body from the hood in order to change the torso angular velocity during re-contact, thus making the torso angle less than 90°prior to the ground contact.

Transparent Composite Films Showing Durable Antifogging and Repeatable Self-Healing Properties Based on an Integral Blend Method.

Antifogging coatings for infrastructures and transparent objects have attracted much attention lately from the perspective of safety and visibility. We have developed a one-pot process to fabricate transparent composite films showing long-lasting antifogging and fast repeatable self-healing properties based on an integral blend (IB) method. This method does not require any specific pretreatments of inorganic fillers/particles. Thus, the precursor solutions could be prepared in a single step by simply mixing raw materials, e.g., poly(vinylpyrrolidone) (PVP) having different molecular weights (MWs: 55, 360, and 1300 k), nano-clay particles (NCPs), and amino-terminated organosilane (AOS). In this study, to control the degree of cross-linking between the PVP matrices and NCPs, addition of AOS as a cross-linker to the PVP matrices (weight percentage of AOS to the PVP matrices, α = 0.01-300%) was carefully controlled. Transparency and self-healing abilities/kinetics of the resulting samples were found to be strongly influenced by both the MWs of PVP and α values. Samples spin-coated with the lowest MW of PVP (55 k) and α values of 0.01-1% gave highly transparent and durable antifogging performance. For example, no fogging was observed for 7 days under >80% relative humidity, and scratches about 30 µm in width could be completely self-healed within a few hours. However, samples with α > 10% gave opaque/grayish films that did not show any self-healing abilities because of an increase in cross-linking of the matrices. The optimized precursor solution was also deposited directly onto the glass slides covered with a transparent porous silica nano-framework (SNF) by a spray-coating method. Due to the formation of the hard and superhydrophilic/hygroscopic SNF with a large surface area, durability of antifogging and self-healing properties of the composite films were moderately improved, compared to those on the flat glass slides.

Mobile health technology as a solution to self-control problems: The behavioral impact of COVID-19 contact tracing apps in Japan.

RATIONALE: Mobile technology has been widely utilized as an effective healthcare tool during the COVID-19 pandemic. Notably, over 50 countries have released contact-tracing apps to trace and contain infection chains. While earlier studies have examined obstacles to app uptake and usage, whether and how this uptake affects users' behavioral patterns is not well understood. This is crucial because uptake can theoretically increase or decrease behavior that carries infection risks. OBJECTIVE: The goal of this study is to evaluate the impact of app uptake on the time spent out of home in Japan. It tests four potential underlying mechanisms that drive the uptake effect: compliance with stay-at-home requirements, learning about infection risk, reminders, and commitment device. METHOD: We use unique nationwide survey data collected from 4,379 individuals aged between 20 and 69 in December 2020 and February 2021 in Japan. Japan has features suitable for this exercise. The Japanese government released a contact tracing app in June 2020, which sends a warning message to users who have been in close contact with an infected person. We conduct a difference-in-differences estimation strategy combined with the entropy balancing method. RESULTS: App uptake reduces the time spent out of home. Sensitivity analysis shows that it cannot be explained by unobserved confounders. Importantly, the impact is large even among users who have not received a warning message from the app, and even larger for those with poor self-control ability. Furthermore, individuals' self-control ability is negatively associated with the uptake decision, supporting our hypothesis that the apps serve as a commitment device. CONCLUSIONS: It may be beneficial to encourage citizens to uptake contact tracing apps and other forms of commitment devices. This study also contributes to the literature on mobile health (mHealth) by demonstrating its efficacy as a commitment device.

Muchas gracias: agradecimiento a los revisores / Thanks a lot

El equipo editorial de Actualizaciones en SIDA e Infectología agradece enormemente a los 37 revisores que han dedicado su tiempo y experiencia al cuidadoso proceso editorial de la revista durante los últimos doce meses. En ese lapso se recibieron y evaluaron 25 trabajos, de los cuales 15 fueron aprobados, 5 rechazados y 5 continuaban en proceso de evaluación al finalizar el año 2021.

Vaccination and altruism under the COVID-19 pandemic.

OBJECTIVES: The goal of this study is to examine the role of altruism and sensitivity to public shame in individuals' willingness to pay for a COVID-19 vaccine. STUDY DESIGN: We apply expected utility theory to predict the role of individuals' altruism and public shame in the willingness to pay for vaccines. Subsequently, we test the prediction by using a unique cross-sectional survey. METHODS: We use online survey data collected from those aged 30-49 in Japan between June 18th and 25th, 2020 (n = 1686). The selection of respondents follows quota sampling with regard to age group, gender, and prefecture of residence. We employ an ordinary least square (OLS) model to regress respondents' willingness to pay for a hypothetically-effective vaccine for COVID-19 on binary indicators of altruism and sensitivity to public shame, as well as socio-demographic characteristics. RESULTS: The willingness to pay for the vaccine is higher among those with stronger altruistic concerns and sensitivity to shaming. CONCLUSION: Voluntary vaccinations may be inefficient, because the uptake of vaccines could be low for selfish individuals who often violate social distancing requirements. To improve the efficiency of vaccine uptake, some interventions, such as nudges and a vaccine passport, may be needed.

Variations in Early-Stage Responses to Pandemics: Survey Evidence from the COVID-19 Pandemic in Japan.

During the initial phase of pandemics, swift behavioral responses by individuals, such as social distancing, can temper the speed and magnitude of further infections. However, individual choices in this period are often made in the absence of reliable knowledge and coordinated policy interventions, producing variation in protective behaviors that cannot be easily deduced from that in later periods. Using unique monthly panel survey data, we examine variations in the association between changes in infections and risky behavior, particularly the frequencies of face-to-face conversations and dining out, between January to March 2020. We find that the increase in confirmed cases is negatively associated with the likelihood of these behaviors. However, high school graduates are less responsive than university graduates. We provide evidence that this can be attributed to their lower perception of infection risk, while we cannot fully rule out the roles of income opportunity costs. These results point to the benefits of interventions incorporating nudges to raise individuals' risk perceptions during the initial phase of pandemics. We also discuss the potential efficacy of such interventions in later periods of pandemics. Supplementary Information: The online version contains supplementary material available at 10.1007/s41885-021-00103-5.

Social media infodemics and social distancing under the COVID-19 pandemic: public good provisions under uncertainty.

This debate examines the impact of infodemics - an over-abundance of information - on social distancing during the COVID-19 pandemic. Because of its external effects, social distancing behavior (SDB) shares fundamental properties with public goods, whose potential for undersupply has been examined extensively in the social sciences. Although the negative effects of infodemics have been emphasized by governments and international organizations, theoretical models suggest that infodemics may work as a mitigation mechanism. That is, infodemics may enhance people's SDBs. Based on original survey data, we show that media exposure can positively increase SDB. We conclude by discussing two public health implications. First, the media plays an important role in motivating SDB. Second, even if infodemics can increase SDB, we must be wary of their ability to pose other, non-negligible dangers.

Prosociality and the Uptake of COVID-19 Contact Tracing Apps: Survey Analysis of Intergenerational Differences in Japan.

BACKGROUND: To control the COVID-19 pandemic, it is essential to trace and contain infection chains; for this reason, policymakers have endorsed the usage of contact tracing apps. To date, over 50 countries have released such apps officially or semiofficially, but those that rely on citizens' voluntary uptake suffer from low adoption rates, reducing their effectiveness. Early studies suggest that the low uptake is driven by citizens' concerns about security and privacy, as well as low perceptions of infection risk and benefits from the usage. However, these do not explore important generational differences in uptake decision or the association between individuals' prosociality and uptake. OBJECTIVE: The objective of our study was to examine the role of individuals' prosociality and other factors discussed in the literature, such as perceived risk and trust in government, in encouraging the usage of contact tracing apps in Japan. We paid particular attention to generational differences. METHODS: A web-based survey was conducted in Japan 6 months after the release of a government-sponsored contact tracing app. Participants were recruited from individuals aged between 20 and 69 years. Exploratory factor analyses were conducted to measure prosociality, risk perception, and trust in government. Logistic regression was used to examine the association between these factors and uptake. RESULTS: There was a total of 7084 respondents, and observations from 5402 respondents were used for analysis, of which 791 respondents (14.6%) had ever used the app. Two factors of prosociality were retained: agreeableness and attachment to the community. Full-sample analysis demonstrated app uptake was determined by agreeableness, attachment to the community, concern about health risks, concern about social risks, and trust in the national government; however, important differences existed. The uptake decision of respondents aged between 20 and 39 years was attributed to their attachment to the community (odds ratio [OR] 1.28, 95% CI 1.11-1.48). Agreeable personality (OR 1.18, 95% CI 1.02-1.35), concern about social risk (OR 1.17, 95% CI 1.02-1.35), and trust in national government (OR 1.16, 95% CI 1.05-1.28) were key determinants for those aged between 40 and 59 years. For those aged over 60 years, concerns about health risks determined the uptake decision (OR 1.49, 95% CI 1.24-1.80). CONCLUSIONS: Policymakers should implement different interventions for each generation to increase the adoption rate of contact tracing apps. It may be effective to inform older adults about the health benefits of the apps. For middle-age adults, it is important to mitigate concerns about security and privacy issues, and for younger generations, it is necessary to boost their attachment to their community by utilizing social media and other web-based network tools.

The bright and dark sides of social media usage during the COVID-19 pandemic: Survey evidence from Japan.

The spread of misinformation on the internet regarding the COVID-19 pandemic, such as unproven or fake cures, has been a serious concern. However, the extent to which social media usage affects individuals' health behavior, particularly when reliable information is scarce, is not well understood. This study evaluates the impact of social media usage on individuals' responses to the COVID-19 pandemic, such as demand for necessities and social distancing. We conduct an original online survey of 1804 Japanese respondents in March 2020. Japan is suitable because it confirmed COVID-19 cases earlier than most other countries. Scientific evidence about the coronavirus and protective measures was scarce in the initial pandemic phase, despite the spread of unconfirmed rumors. Our analysis focuses on the usage of Twitter, Facebook, and Instagram. We use the entropy balancing method to control for heterogeneity in observed characteristics between social media users and non-users. The results show that while users are more likely to maintain social distancing practices, they are also more likely to take measures whose reliability is not scientifically confirmed, such as eating fermented soybeans. Although previous studies emphasize the negative effects of social media, our results suggest that it has both bright and dark sides.

Analysis of kinematic behavior of pedestrians/cyclists in vehicle collisions using impulse.

Objective: In order to further reduce the injury risks to pedestrians/cyclists in vehicle collisions, it is necessary to control pedestrian/cyclist kinematics. To investigate pedestrian/cyclist kinematic behavior from initial contact with the vehicle to the ground contact, it is necessary to evaluate the force interactions between the pedestrian/cyclist body region and the car body during the crash event.Method: Finite element analysis was conducted for models of pedestrians and cyclists being struck by a car around the center, left, and right sides of the front of the vehicle at 40 km/h. The impulse that was applied to each body region of the pedestrian/cyclist by the vehicle body during the impact was employed to analyze the kinematic behavior of the pedestrian/cyclist.Results: An impulse-time history can be separated into three stages. In the first stage, the pedestrian/cyclist was accelerated by the vehicle's forward impulse imparted to the subject due to the lower extremities contacting the bumper and hood leading edge. In the second stage, the pedestrian/cyclist rotates around the hood leading edge. In the third stage, the pedestrian/cyclist was accelerated in the vehicle forward and upward directions by the impulse resulting from the contact of the head and upper extremities with the cowl and the windshield. As the impulse to the lower extremity increased, the wraparound distance (WAD) decreased; however, the pelvis velocity in the forward direction increased.Conclusion: This research employed a new approach using the impulse transmitted to each body region due to contact with the vehicle body and showed that impulse is a useful parameter to understand the process of pedestrian/cyclist kinematics. The impulse relates to the linear and angular velocities of the pedestrian/cyclist at the time of separation from the car, thereby providing useful information to control pedestrian/cyclist falling kinematics prior to the ground impact.

Mitochondrial Dynamics Regulation in Skin Fibroblasts from Mitochondrial Disease Patients.

Mitochondria are highly dynamic organelles that constantly fuse, divide, and move, and their function is regulated and maintained by their morphologic changes. Mitochondrial disease (MD) comprises a group of disorders involving mitochondrial dysfunction. However, it is not clear whether changes in mitochondrial morphology are related to MD. In this study, we examined mitochondrial morphology in fibroblasts from patients with MD (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and Leigh syndrome). We observed that MD fibroblasts exhibited significant mitochondrial fragmentation by upregulation of Drp1, which is responsible for mitochondrial fission. Interestingly, the inhibition of mitochondrial fragmentation by Drp1 knockdown enhanced cellular toxicity and led to cell death in MD fibroblasts. These results suggest that mitochondrial fission plays a critical role in the attenuation of mitochondrial damage in MD fibroblasts.

Mismatch repair systems might facilitate the chromosomal recombination induced by N-nitrosodimethylamine, but not by N-nitrosodiethylamine, in Drosophila.

Mismatch repair (MMR) systems play important roles in maintaining the high fidelity of genomic DNA. It is well documented that a lack of MMR increases the mutation rate, including base exchanges and small insertion/deletion loops; however, it is unknown whether MMR deficiency affects the frequency of chromosomal recombination in somatic cells. To investigate the effects of MMR on chromosomal recombination, we used the Drosophila wing-spot test, which efficiently detects chromosomal recombination. We prepared MMR (MutS)-deficient flies (spel1(-/-)) using a fly line generated in this study. The spontaneous mutation rate as measured by the wing-spot test was slightly higher in MutS-deficient flies than in wild-type (spel1(+/-)) flies. Previously, we showed that N-nitrosodimethylamine (NDMA)-induced chromosomal recombination more frequently than N-nitrosodiethylamine (NDEA) in Drosophila. When the wing-spot test was performed using MMR-deficient flies, unexpectedly, the rate of NDMA-induced mutation was significantly lower in spel1(-/-) flies than in spel1(+/-) flies. In contrast, the rate of mutation induced by NDEA was higher in spel1(-/-) flies than in spel1(+/-) flies. These results suggest that in Drosophila, the MutS homologue protein recognises methylated DNA lesions more efficiently than ethylated ones, and that MMR might facilitate mutational chromosomal recombination due to DNA double-strand breaks via the futile cycle induced by MutS recognition of methylated lesions.

Polymerization-Depolymerization System Based on Reversible Addition-Dissociation Reaction of 1,3-Benzoxazine with Thiol.

The reversible nature of the addition reaction of 1,3-benzoxazine and thiol at ambient temperature was discovered by investigating the reaction with using p-cresol-derived N-phenyl benzoxazine 1 and 1-octadecanethiol 2. The reaction was performed in several deuteriated media involving CDCl3 and CDCl3 + CD3OD, for monitoring their reaction by 1H NMR spectrometry. CDCl3 was a favorable solvent for the efficient progress of the reaction, and its combination with CD3OD allowed further acceleration of the reaction. In both cases, the reaction proceeded until conversion of 1 reached a certain ceiling value, to suggest that the reaction was reversible. This reversible nature was concretely confirmed by finding a dissociation reaction of isolated 3 into 1 and 2 in CDCl3. Analogously, a bisphenol A-derived bifunctional benzoxazine 4 and 1,6-hexanedithiol 5 underwent the polyaddition in CDCl3 + CD3OD at ambient temperature to afford the corresponding polymer 6. Successful depolymerization of 6 into small fragments was achieved by dissolving 6 in CDCl3.