On the universality of the I-V switching characteristics in non-volatile and volatile resistive switching oxides.

The I-V switching curves of bipolar switching non-volatile ReRAM devices show peculiar characteristics, such as an abrupt ON switching and the existence of a universal switching voltage. This switching behavior has been explained by the presence of a filamentary process, in which the width of a conductive filament changes during switching resulting in different resistance states. Vice versa, similar (ON) switching behavior, e.g. that of volatile switching Cr-doped V2O3 devices, has been interpreted as an indication of the presence of similar filamentary switching. In this paper, we want to review the correlation between filamentary (width) switching and the (SET) I-V characteristics by discussing the existing models. For the Cr-doped V2O3 devices, on the other hand, it is argued that a different, constant filament width switching mode may be present.

Host Cell Copper Transporters CTR1 and ATP7A are important for Influenza A virus replication.

BACKGROUND: The essential role of copper in eukaryotic cellular physiology is known, but has not been recognized as important in the context of influenza A virus infection. In this study, we investigated the effect of cellular copper on influenza A virus replication. METHODS: Influenza A/WSN/33 (H1N1) virus growth and macromolecule syntheses were assessed in cultured human lung cells (A549) where the copper concentration of the growth medium was modified, or expression of host genes involved in copper homeostasis was targeted by RNA interference. RESULTS: Exogenously increasing copper concentration, or chelating copper, resulted in moderate defects in viral growth. Nucleoprotein (NP) localization, neuraminidase activity assays and transmission electron microscopy did not reveal significant defects in virion assembly, morphology or release under these conditions. However, RNAi knockdown of the high-affinity copper importer CTR1 resulted in significant viral growth defects (7.3-fold reduced titer at 24 hours post-infection, p = 0.04). Knockdown of CTR1 or the trans-Golgi copper transporter ATP7A significantly reduced polymerase activity in a minigenome assay. Both copper transporters were required for authentic viral RNA synthesis and NP and matrix (M1) protein accumulation in the infected cell. CONCLUSIONS: These results demonstrate that intracellular copper regulates the influenza virus life cycle, with potentially distinct mechanisms in specific cellular compartments. These observations provide a new avenue for drug development and studies of influenza virus pathogenesis.

Alphavirus RNA synthesis and non-structural protein functions.

The members of the genus Alphavirus are positive-sense RNA viruses, which are predominantly transmitted to vertebrates by a mosquito vector. Alphavirus disease in humans can be severely debilitating, and depending on the particular viral species, infection may result in encephalitis and possibly death. In recent years, alphaviruses have received significant attention from public health authorities as a consequence of the dramatic emergence of chikungunya virus in the Indian Ocean islands and the Caribbean. Currently, no safe, approved or effective vaccine or antiviral intervention exists for human alphavirus infection. The molecular biology of alphavirus RNA synthesis has been well studied in a few species of the genus and represents a general target for antiviral drug development. This review describes what is currently understood about the regulation of alphavirus RNA synthesis, the roles of the viral non-structural proteins in this process and the functions of cis-acting RNA elements in replication, and points to open questions within the field.

Modeling the injury prevention impact of mandatory alcohol ignition interlock installation in all new US vehicles.

OBJECTIVES: We estimated the injury prevention impact and cost savings associated with alcohol interlock installation in all new US vehicles. METHODS: We identified fatal and nonfatal injuries associated with drinking driver vehicle crashes from the Fatality Analysis Reporting System and National Automotive Sampling System's General Estimates System data sets (2006-2010). We derived the estimated impact of universal interlock installation using an estimate of the proportion of alcohol-related crashes that were preventable in vehicles < 1 year-old. We repeated this analysis for each subsequent year, assuming a 15-year implementation. We applied existing crash-induced injury cost metrics to approximate economic savings, and we used a sensitivity analysis to examine results with varying device effectiveness. RESULTS: Over 15 years, 85% of crash fatalities (> 59 000) and 84% to 88% of nonfatal injuries (> 1.25 million) attributed to drinking drivers would be prevented, saving an estimated $342 billion in injury-related costs, with the greatest injury and cost benefit realized among recently legal drinking drivers. Cost savings outweighed installation costs after 3 years, with the policy remaining cost effective provided device effectiveness remained above approximately 25%. CONCLUSIONS: Alcohol interlock installation in all new vehicles is likely a cost-effective primary prevention policy that will substantially reduce alcohol-involved crash fatalities and injuries, especially among young vulnerable drivers.

Reducing firearm access for youth at risk for suicide in a pediatric emergency department.

Background: Firearm-related suicide is the second leading cause of pediatric firearm death. Lethal means counseling (LMC) can improve firearm safe-storage practices for families with youth at risk of suicide. Objectives: This study aims to evaluate the feasibility of pediatric emergency department (ED) behavioral mental health (BMH) specialists providing LMC to caregivers of youth presenting with BMH complaints and to test for changes in firearm safety practices, pre-post ED LMC intervention, as measures of preliminary efficacy. Methods: Prospective pilot feasibility study of caregivers of youth presenting to a pediatric ED with BMH complaints. Caregivers completed an electronic survey regarding demographics and firearm safe-storage knowledge/practices followed by BMH specialist LMC. Firearm owners were offered a free lockbox and/or trigger lock. One-week follow-up surveys gathered self-reported data on firearm safety practices and intervention acceptability. One-month interviews with randomly sampled firearm owners collected additional firearm safety data. Primary outcomes were feasibility measures, including participant accrual/attrition and LMC intervention acceptability. Secondary outcomes included self-reported firearm safety practice changes. Feasibility benchmarks were manually tabulated, and Likert-scale acceptability responses were dichotomized to strongly agree/agree vs. neutral/disagree/strongly disagree. Descriptive statistics were used for univariate and paired data responses. Results: In total, 81 caregivers were approached; of which, 50 (81%) caregivers enrolled. A total of 44% reported having a firearm at home, 80% completed follow-up at one week. More than 80% affirmed that ED firearm safety education was useful and that the ED is an appropriate place for firearm safety discussions. In total, 58% of participants reported not having prior firearm safety education/counseling. Among firearm owners (n = 22), 18% reported rarely/never previously using a safe-storage device, and 59% of firearm owners requested safe storage devices.At 1-week follow-up (n = 40), a greater proportion of caregivers self-reported asking about firearms before their child visited other homes (+28%). Among firearm owners that completed follow-up (n = 19), 100% reported storing all firearms locked at one week (+23% post-intervention). In total, 10 caregivers reported temporarily/permanently removing firearms from the home. Conclusion: It is feasible to provide LMC in the pediatric ED via BMH specialists to families of high-risk youth. Caregivers were receptive to LMC and reported finding this intervention useful, acceptable, and appropriate. Additionally, LMC and device distribution led to reported changes in safe storage practices.

Understanding the new trends in pedestrian injury distribution and mechanism through data linkage and modeling.

The objectives of this study were to 1) collect and analyze recent pedestrian crash cases for better understanding of the pedestrian injury distribution and mechanism, 2) use computational simulations to reconstruct pedestrian cases and estimate potential benefit of pedestrian automatic emergency braking (PedAEB) in reducing pedestrian injury risks, and 3) estimate how future pedestrian crash distribution might influence priorities for pedestrian protection. Analyses of national crash-injury dataset showed that the overall number of pedestrians in crashes as well as the serious and fatal pedestrian injuries in the U.S. have been increasing in recent years. Striking vehicle type has changed (i.e., decreased proportion of passenger cars and increase of SUVs and pickup trucks) from 20 years ago mirroring changes in the fleet distribution of vehicle sales. A total of 432 pedestrian injury cases were generated by linking the Michigan trauma data and police-reported crash data from 2013 to 2018. Among the linked cases, pickup trucks and SUVs were involved in crashes with more injuries across body regions. Notably, AIS 3+ chest injuries occur at almost the same rate as lower extremity injuries. A method, combining MADYMO simulations (n = 3,500), response surface model, and data mining, was developed to reconstruct 25 linked pedestrian crash cases to estimate the effectiveness of PedAEB. Based on national field data and MADYMO simulations, PedAEB was estimated to be effective in reducing the risk of head and lower extremity injuries but is relatively less effective in reducing the risk of chest injuries. The increased proportions of SUVs and pickup trucks in the vehicle fleet and the higher penetration of PedAEB may highlight the importance of future research into chest injury risk for pedestrian protection.

Requirement for the amino-terminal domain of sindbis virus nsP4 during virus infection.

The Sindbis virus RNA-dependent RNA polymerase nsP4 possesses an amino-terminal region that is unique to alphaviruses and is predicted to be disordered. To determine the importance of this region during alphavirus replication, 29 mutations were introduced, and resultant viruses were assessed for growth defects. Three small plaque mutants, D41A, G83L, and the triple mutant GPG((8-10))VAV, had defects in subgenome synthesis, minus-strand synthesis, and overall levels of viral RNA synthesis, respectively. Large plaque viruses were selected following passage in BHK-21 cells, and the genomes of these were sequenced. Suppressor mutations in nsP1, nsP2, and nsP3 that restored viral RNA synthesis were identified. An nsP2 change from M282 to L and an nsP3 change from H99 to N corrected the D41A-induced defect in subgenomic RNA synthesis. Three changes in nsP1, I351 to V, I388 to V, or the previously identified change, N374 to H (C. L. Fata, S. G. Sawicki, and D. L. Sawicki, J. Virol. 76:8641-8649, 2002), suppressed the minus-strand synthetic defect. A direct reversion back to G at position 8 reduced the RNA synthesis defect of the GPG((8-10))VAV virus. These results imply that nsP4's amino-terminal domain participates in distinct interactions with other nsPs in the context of differentially functioning RNA synthetic complexes, and flexibility in this domain is important for viral RNA synthesis. Additionally, the inability of the mutant viruses to efficiently inhibit host protein synthesis suggests a role for nsP4 in the regulation of host cell gene expression.

Effect of frozen storage on dynamic tensile properties of human placenta.

Dynamic mechanical properties of placenta tissue are needed to develop computational models of pregnant occupants for use in designing restraint systems that protect the fetus and mother. Tests were performed on 21 samples obtained from five human placentas at a rate of 1200 %/s using a set of custom designed thermoelectrically cooled clamps. Approximately half of the samples from all five subjects were tested within 48 h of delivery. The remaining samples were frozen for 5-7 days and then thawed before testing. True failure stresses and strains were not significantly different between fresh and frozen samples (p-value = 0.858 and 0.551, respectively), suggesting that soft tissue may be stored frozen up to a week without adversely affecting dynamic material response.

Patient Characteristics and Perspectives of Firearm Safety Discussions in the Emergency Department.

INTRODUCTION: Firearm injury prevention discussions with emergency department (ED) patients provide a unique opportunity to prevent death and injury in high-risk patient groups. Building mutual understanding of safe firearm practices between patients and providers will aid the development of effective interventions. Examining ED patient baseline characteristics, perspectives on healthcare-based safety discussions, and experience with and access to firearms, will allow practitioners to craft more effective messaging and interventions. METHODS: Using an institutional review board-approved cross-sectional survey modified from a validated national instrument, we recruited 625 patients from three large, urban, academically affiliated EDs in the South to assess patient baseline characteristics, perspectives regarding firearms and firearm safety discussions, and prior violence history, as well as firearm access and safety habits. We compared the degree to which patients were open to discussions regarding firearms across a variety of provider types and clinical scenarios between those with and without gun access. RESULTS: Of the 625 patients consented and eligible for the study, 306 had access to firearms. The patients with firearm access were predominantly male, were more likely to have military experience, live in an urban or suburban region, and have experienced prior violence when compared to those without firearm access. Patients with and without gun access view firearm safety discussions with their healthcare provider as acceptable and analogous to other behavioral health interventions (i.e., helmet/seat belt use, alcohol/cigarette use). Patients were also accepting of these firearm safety discussions in many clinical contexts and led by multiple provider types. Of the patients with gun access, storage of each type of firearm was reviewed and the primary reason for ownership was for personal protection across all firearm types. CONCLUSION: Patients in the ED indicate openness to firearm safety discussions delivered by a variety of providers and in diverse clinical scenarios. Healthcare providers engaging firearm owners in appropriate risk-benefit discussions using a trauma-informed approach is a critical next step in research and intervention.

The Effect of Nighttime Rental Restrictions on E-Scooter Injuries at a Large Urban Tertiary Care Center.

Safety policy for e-scooters in the United States tends to vary by municipality, and the effects of safety interventions have not been well studied. We reviewed medical records at a large, urban tertiary care and trauma center in Atlanta, Georgia with the goal of identifying trends in e-scooter injury and the effects of Atlanta's nighttime ban on e-scooter rentals on injuries treated in the emergency department (ED). Records from all ED visits occurring between June 2018 through August 2020 were reviewed. To account for ambiguity in medical records, confidence levels of either "certain" or "possible" were assigned using a set of predefined criteria to categorize patient injuries as being associated with an e-scooter. A total of 380 patients categorized as having certain e-scooter related injuries were identified. The average age of these patients was 31 years old, 65% were male, 41% had head injuries, 20% of injuries were associated with the built environment, and approximately 20% were admitted to the hospital. Approximately 19% of patients with injuries associated with e-scooters noted to be clinically intoxicated or have a serum ethanol level exceeding 80 mg/dL. The implementation of a nighttime rental ban on e-scooter rentals reduced the proportion of patients with e-scooter injuries with times of arrival during the hours of the ban from 32% to 22%, however this effect was not significant (p = 0.16). More research is needed to understand how e-scooter use patterns are affected by the nighttime rental ban.

Self-Reported Use of Personal Protective Equipment among Emergency Department Nurses, Physicians and Advanced Practice Providers during the 2020 COVID-19 Pandemic.

BACKGROUND: Emergency departments (EDs) have seen dramatic surges in patients infected with COVID-19 and are high-risk transmission environments. Knowledge, attitudes and practice regarding personal protective equipment (PPE) among ED health care workers (HCWs) during the COVID-19 pandemic have not been studied, thus this study examines this knowledge gap. METHODS: This was a cross-sectional survey of 308 HCWs in two urban EDs in Atlanta, Georgia in April and May of 2020. RESULTS: We surveyed 308 HCWs; 137 responded (44% response rate). All HCWs reported adequate knowledge and 96% reported compliance with PPE guidelines. Reported sources of PPE information: 56.7% charge nurse, 67.3% the institutional COVID-19 website. Frequency of training was positively associated with understanding how to protect themselves and patients (OR = 1.7, 95% CI: 1.0-2.9). CONCLUSIONS: Few HCWs are willing to care for patients without PPE, and therefore we should aim for resiliency in the PPE supply chain. EDs should consider multiple communication strategies, including a website with concise information and enhanced training for key personnel, particularly the charge nurse. Attention to frequency in HCW training may be key to improve confidence in protecting themselves and patients. Findings can be leveraged by EDs to implement effective PPE training.

Whole Body PMHS Response in Injurious Experimental Accelerative Loading Events.

Previous studies involving whole-body post-mortem human surrogates (PHMS) have generated biomechanical response specifications for physically simulated accelerative loading intended to reproduce seat and floor velocity histories occurring in under-body blast (UBB) events (e.g.,. References 10, 11, 21 These previous studies employed loading conditions that only rarely produced injuries to the foot/ankle and pelvis, which are body regions of interest for injury assessment in staged UBB testing using anthropomorphic test devices. To investigate more injurious whole-body conditions, three series of tests were conducted with PMHS that were equipped with military personal protective equipment and seated in an upright posture. These tests used higher velocity and shorter duration floor and seat inputs than were previously used with the goal of producing pelvis and foot/ankle fractures. A total of nine PMHS that were approximately midsize in stature and mass were equally allocated across three loading conditions, including a 15.5 m/s, 2.5 ms time-to-peak (TTP) floor velocity pulse with a 10 m/s, 7.5 ms TTP seat pulse; a 13 m/s, 2.5 ms TTP floor pulse with a 9.0 m/s, 5 ms TTP seat pulse; and a 10 m/s, 2.5 ms TTP floor pulse with a 6.5 m/s, 7.5 ms TTP seat pulse. In the first two conditions, the seat was padded with a ~ 120-mm-thick foam cushion to elongate the pulse experienced by the PMHS. Of the nine PMHS tests, five resulted in pelvic ring fractures, five resulted in a total of eight foot/ankle fractures (i.e., two unilateral and three bilateral fractures), and one produced a femur fracture. Test results were used to develop corridors describing the variability in kinematics and in forces applied to the feet, forces applied to the pelvis and buttocks in rigid seat tests, and in forces applied to the seat foam in padded seat tests. These corridors and the body-region specific injury/no-injury response data can be used to assess the performance and predictive capability of anthropomorphic test devices and computational models used as human surrogates in simulated UBB testing.

Anatomically-based skeletal coordinate systems for use with impact biomechanics data intended for anthropomorphic test device development.

Post-mortem human subjects (PMHS) are frequently used to characterize biomechanical response and injury tolerance of humans to various types of loading by means of instrumentation installed directly on the skeleton. Data extracted from such tests are often used to develop and validate anthropomorphic test devices (ATDs), which function as human surrogates in tests for injury assessment. Given that the location and orientation of installed instrumentation differs between subjects, nominally similar measurements made on different PMHS must be transformed to standardized, skeletal-based local coordinate systems (LCS) before appropriate data comparisons can be made. Standardized PMHS LCS that correspond to ATD instrumentation locations and orientations have not previously been published. This paper introduces anatomically-defined PMHS LCS for body regions in which kinematic measurements are made using ATDs. These LCS include the head, sternum, single vertebrae, pelvis, femurs (distal and proximal), and tibiae (distal and proximal) based upon skeletal landmarks extracted from whole body CT scans. The proposed LCS provide a means to standardize the reporting of PMHS data, and facilitate both the comparison of PMHS impact data across institutions and the application of PMHS data to the development and validation of ATDs.

Kinematic and Biomechanical Response of Post-Mortem Human Subjects Under Various Pre-Impact Postures to High-Rate Vertical Loading Conditions.

Limited data exist on the injury tolerance and biomechanical response of humans to high-rate, under-body blast (UBB) loading conditions that are commonly seen in current military operations, and there are no data examining the influence of occupant posture on response. Additionally, no anthropomorphic test device (ATD) currently exists that can properly assess the response of humans to high-rate UBB loading. Therefore, the purpose of this research was to examine the response of post-mortem human surrogates (PMHS) in various seated postures to high-rate, vertical loading representative of those conditions seen in theater. In total, six PMHS tests were conducted using loading pulses applied directly to the pelvis and feet of the PMHS: three in an acute posture (foot, knee, and pelvis angles of 75°, 75°, and 36°, respectively), and three in an obtuse posture (15° reclined torso, and foot, knee, and pelvis angles of 105°, 105°, and 49.5°, respectively). Tests were conducted with a seat velocity pulse that peaked at ~4 m/s with a 30-40 ms time to peak velocity (TTP) and a floor velocity that peaked at 6.9-8.0 m/s (2-2.75 ms TTP). Posture condition had no influence on skeletal injuries sustained, but did result in altered leg kinematics, with leg entrapment under the seat occurring in the acute posture, and significant forward leg rotations occurring in the obtuse posture. These data will be used to validate a prototype ATD meant for use in high-rate UBB loading scenarios.

Fetal outcome in motor-vehicle crashes: effects of crash characteristics and maternal restraint.

OBJECTIVE: This project was undertaken to improve understanding of factors associated with adverse fetal outcomes of pregnant occupants involved in motor-vehicle crashes. STUDY DESIGN: In-depth investigations of crashes involving 57 pregnant occupants were performed. Maternal and fetal injuries, restraint information, measures of external and internal vehicle damage, and details about the crash circumstances were collected. Crash severity was calculated using vehicle crush measurements. Chi-square analysis and logistic regression models were used to determine factors with a significant association with fetal outcome. RESULTS: Fetal outcome is most strongly associated with crash severity (P < .001) and maternal injury (P = .002). Proper maternal belt-restraint use (with or without airbag deployment) is associated with acceptable fetal outcome (odds ratio = 4.5, P = .033). Approximately half of fetal losses in motor-vehicle crashes could be prevented if all pregnant women properly wore seat belts. CONCLUSION: Higher crash severity, more severe maternal injury, and lack of proper seat belt use are associated with a higher risk of adverse fetal outcome. These results strongly support recommendations that pregnant women use properly positioned seatbelts.

The influence of pre-existing rib fractures on Global Human Body Models Consortium thorax response in frontal and oblique impact.

Many post-mortem human subjects (PMHS) considered for use in biomechanical impact tests have pre-existing rib fractures (PERFs), usually resulting from cardiopulmonary resuscitation. These specimens are typically excluded from impact studies with the assumption that the fractures will alter the thoracic response to loading. We previously used the Global Human Body Models Consortium 50th percentile whole-body finite element model (GHBMC M50-O) to demonstrate that up to three lateral or bilateral PERFs do not meaningfully influence the response of the GHBMC thorax to lateral loading. This current study used the GHBMC M50-O to explore the influence of PERFs on thorax response in frontal and oblique loading. Up to six PERFs were simulated on the anterior or lateral rib regions, and the model was subjected to frontal or oblique cylindrical impactor, frontal seatbelt, or frontal seatbelt + airbag loading. Changes in thorax force-compression responses due to PERFs were generally minor, with the greatest alterations seen in models with six PERFs on one side of the ribcage. The observed changes, however, were small relative to mid-size male corridors for the loading conditions simulated. PERFs altered rib strain patterns, but the changes did not translate to changes in global thoracic response. Within the limits of model fidelity, the results suggest that PMHS with up to six PERFs may be appropriate for use in frontal or oblique impact testing.

Pediatric falls ages 0-4: understanding demographics, mechanisms, and injury severities.

BACKGROUND: Pediatric unintentional falls are the leading cause of injury-related emergency visits for children < 5 years old. The purpose of this study was to identify population characteristics, injury mechanisms, and injury severities and patterns among children < 5 years to better inform age-appropriate falls prevention strategies. METHODS: This retrospective database study used trauma registry data from the lead pediatric trauma system in Georgia. Data were analyzed for all patients < 5 years with an international classification of disease, 9th revision, clinical modification (ICD-9 CM) external cause of injury code (E-code) for unintentional falls between 1/1/2013 and 12/31/2015. Age (months) was compared across categories of demographic variables, injury mechanisms, and emergency department (ED) disposition using Kruskal-Wallis ANOVA and the Mann Whitney U test. The relationships between demographic variables, mechanism of injury (MOI), and Injury Severity Score (ISS) were evaluated using multinomial logistic regression. RESULTS: Inclusion criteria were met by 1086 patients (median age = 28 months; 59.7% male; 53.8% White; 49.1% <  1 m fall height). Younger children, < 1-year-old, primarily fell from caregiver's arms, bed, or furniture, while older children sustained more falls from furniture and playgrounds. Children who fell from playground equipment were older (median = 49 months, p < 0.01) than those who fell from the bed (median = 10 months), stairs (median = 18 months), or furniture (median = 19 months). Children < 1 year had the highest proportion of head injuries including skull fracture (63.1%) and intracranial hemorrhage (65.5%), 2-year-old children had the highest proportion of femur fractures (32.9%), and 4-year-old children had the highest proportion of humerus fractures (41.0%). Medicaid patients were younger (median = 24.5 months, p < 0.01) than private payer (median = 34 months). Black patients were younger (median = 20.5 months, p < 0.001) than White patients (median = 29 months). Results from multinomial logistic regression models suggest that as age increases, odds of a severe ISS (16-25) decreased (OR = 0.95, CI = 0.93-0.97). CONCLUSIONS: Pediatric unintentional falls are a significant burden of injury for children < 5 years. Future work will use these risk and injury profiles to inform current safety recommendations and develop evidence-based interventions for parents/caregivers and pediatric providers.

Optimizing Seat Belt and Airbag Designs for Rear Seat Occupant Protection in Frontal Crashes.

Recent field data have shown that the occupant protection in vehicle rear seats failed to keep pace with advances in the front seats likely due to the lack of advanced safety technologies. The objective of this study was to optimize advanced restraint systems for protecting rear seat occupants with a range of body sizes under different frontal crash pulses. Three series of sled tests (baseline tests, advanced restraint trial tests, and final tests), MADYMO model validations against a subset of the sled tests, and design optimizations using the validated models were conducted to investigate rear seat occupant protection with 4 Anthropomorphic Test Devices (ATDs) and 2 crash pulses. The sled tests and computer simulations were conducted with a variety of restraint systems including the baseline rear-seat 3-point belt, 3-point belts with a pre-tensioner, load limiter, dynamic locking tongue, 4-point belts, inflatable belts, Bag in Roof (BiR) concept, and Self Conforming Rear seat Air Bag (SCaRAB) concept. The results of the first two sled series demonstrated that the baseline 3-point belt system are associated with many injury measures exceeding injury assessment reference values (IARVs); showed the significance of crash pulse and occupant size in predicting injury risks; and verified the potential need of advanced restraint features for better protecting the rear-seat occupants. Good correlations between the tests and simulations were achieved through a combination of optimization and manual fine-tuning, as determined by a correlation method. Parametric simulations showed that optimized belt-only designs (3-point belt with pre-tensioner and load limiter) met all of the IARVs under the soft crash pulse but not the severe crash pulse, while the optimized belt and SCaRAB design met all the IARVs under both the soft and severe crash pulses. Two physical prototype restraint systems, namely an "advanced-belt only" design and an "advanced-belt and SCaRAB" design, were then tested in the final sled series. With the soft crash pulse, both advanced restraint systems were able to reduce all the injury measures below the IARVs for all four ATDs. Both advanced restraint systems also effectively reduced almost all the injury measures for all ATDs under the severe crash pulse, except for the THOR. The design with the advanced-belt and SCaRAB generally provided lower injury measures than those using the advanced belt-only design. This study highlighted the potential benefit of using advanced seatbelt and airbag systems for rear-seat occupant protection in frontal crashes.

The influence of personal protection equipment, occupant body size, and restraint system on the frontal impact responses of Hybrid III ATDs in tactical vehicles.

OBJECTIVE: Although advanced restraint systems, such as seat belt pretensioners and load limiters, can provide improved occupant protection in crashes, such technologies are currently not utilized in military vehicles. The design and use of military vehicles presents unique challenges to occupant safety-including differences in compartment geometry and occupant clothing and gear-that make direct application of optimal civilian restraint systems to military vehicles inappropriate. For military vehicle environments, finite element (FE) modeling can be used to assess various configurations of restraint systems and determine the optimal configuration that minimizes injury risk to the occupant. The models must, however, be validated against physical tests before implementation. The objective of this study was therefore to provide the data necessary for FE model validation by conducting sled tests using anthropomorphic test devices (ATDs). A secondary objective of this test series was to examine the influence of occupant body size (5th percentile female, 50th percentile male, and 95th percentile male), military gear (helmet/vest/tactical assault panels), seat belt type (3-point and 5-point), and advanced seat belt technologies (pretensioner and load limiter) on occupant kinematics and injury risk in frontal crashes. METHODS: In total, 20 frontal sled tests were conducted using a custom sled buck that was reconfigurable to represent both the driver and passenger compartments of a light tactical military vehicle. Tests were performed at a delta-V of 30 mph and a peak acceleration of 25 g. The sled tests used the Hybrid III 5th percentile female, 50th percentile male, and 95th percentile male ATDs outfitted with standard combat boots and advanced combat helmets. In some tests, the ATDs were outfitted with additional military gear, which included an improved outer tactical vest (IOTV), IOTV and squad automatic weapon (SAW) gunner with a tactical assault panel (TAP), or IOTV and rifleman with TAP. ATD kinematics and injury outcomes were determined for each test. RESULTS: Maximum excursions were generally greater in the 95th percentile male compared to the 50th percentile male ATD and in ATDs wearing TAP compared to ATDs without TAP. Pretensioners and load limiters were effective in decreasing excursions and injury measures, even when the ATD was outfitted in military gear. CONCLUSIONS: ATD injury response and kinematics are influenced by the size of the ATD, military gear, and restraint system. This study has provided important data for validating FE models of military occupants, which can be used for design optimization of military vehicle restraint systems.