In Silico Investigation of Biomechanical Response of a Human Brain Subjected to Primary Blast

The brain response to the explosion-induced primary blast waves is actively sought. Over the past decade, reasonable progress has been made in the fundamental understanding of blast traumatic brain injury (bTBI) using head surrogates and animal models. Yet, the current understanding of how blast waves interact with human is in nascent stages, primarily due to the lack of data in human. The biomechanical response in human is critically required to faithfully establish the connection to the aforementioned bTBI models. In this work, the biomechanical cascade of the brain under a primary blast has been elucidated using a detailed, full-body human model. The full-body model allowed us to holistically probe short- (<5 ms) and long-term (200 ms) brain responses. The full-body model has been extensively validated against impact loading in the past. We have further validated the head model against blast loading. We have also incorporated the structural anisotropy of the brain white matter. The blast wave transmission, and linear and rotational motion of the head were dominant pathways for the loading of the brain, and these loading paradigms generated distinct biomechanical fields within the brain. Blast transmission and linear motion of the head governed the volumetric response, whereas the rotational motion of the head governed the deviatoric response. Blast induced head rotation alone produced diffuse injury pattern in white matter fiber tracts. The biomechanical response under blast was comparable to the impact event. These insights will augment laboratory and clinical investigations of bTBI and help devise better blast mitigation strategies.

24Model-based comparative analysis of two catastrophic hazardous chemical pipeline accidents

Objectives. This study conducted a comparative analysis of two catastrophic pipeline accidents in China in order to identify some common mistakes and lessons learned to prevent similar accidents. Methods. The 24Model was used in this study, which provides a universal pathway for accident analysis from the individual level to the organizational level. Results. There were similarities between the two cases in the aspects of the occurrence, development, emergency and causation at different levels: both were caused by leaks of pipelines and evolved into multiple explosions during emergency response; both leaks were caused by the corrosion of pipelines in the confined space of a damp or salt-spray environment; both were classified as 'responsibility accidents', and unsafe acts, such as the failure to identify hidden hazards of pipelines that were the direct cause of accidents, reflected the shortcomings of individual safety habitual behaviour in terms of knowledge, awareness, habits and psychology; weaknesses in the organizational management mainly concerned hazard identification, pipeline maintenance, emergency disposal, etc.; and there is not a good safety climate within the organization. Conclusions. Organizations should develop a closed-loop management system and strengthen the construction of safety culture, and the government should supervise the implementation of procedures.

The dynamic response of human lungs due to underwater shock wave exposure

Since the 19th century, underwater explosions have posed a significant threat to service members. While there have been attempts to establish injury criteria for the most vulnerable organs, namely the lungs, existing criteria are highly variable due to insufficient human data and the corresponding inability to understand the underlying injury mechanisms. This study presents an experimental characterization of isolated human lung dynamics during simulated exposure to underwater shock waves. We found that the large acoustic impedance at the surface of the lung severely attenuated transmission of the shock wave into the lungs. However, the shock wave initiated large bulk pressure-volume cycles that are distinct from the response of the solid organs under similar loading. These pressure-volume cycles are due to compression of the contained gas, which we modeled with the Rayleigh-Plesset equation. The extent of these lung dynamics was dependent on physical confinement, which in real underwater blast conditions is influenced by factors such as rib cage properties and donned equipment. Findings demonstrate a potential causal mechanism for implosion injuries, which has significant implications for the understanding of primary blast lung injury due to underwater blast exposures.

Dropping a bombshell: Acoustic characterization of blast fishing in Todos os Santos Bay, Brazil, and its implication for marine conservation

Blast fishing is an illegal fishing method that not only affects fish populations and the marine ecosystem, but also local food security and local economy. Despite its effects, blast fishing continues to persist in many coastal regions around the world, including Todos os Santos Bay (BTS - Baia de Todos os Santos) in Northeastern Brazil. This study provides the first acoustic record of underwater explosions along this region. The acoustic data were collected between 2016 and 2018, from a boat-survey platform, using a portable system consisting of an HTI-90 min hydrophone (sensitivity of about -165 dB re 1 V/μPa) connected to a TASCAM DR-40 digital recorder (combined frequency response up to 30 kHz), recording at 7 m depth. The acoustic analysis was performed using both RAVEN 1.6 and MATLAB 2021a softwares. The results revealed a distinctive underwater explosion signal detected in the BTS, indicating evidence of blast fishing activities. The acoustic characterization of blast fishing in BTS provides crucial information on its occurrence and extent of this destructive practice worldwide.

Freezing pre-treatment improves radio frequency explosion puffing (RFEP) quality by altering the cellular structure of purple sweet potato [Ipomoea batatas (L) Lam.]

Radio frequency explosion puffing (RFEP) is a novel oil-free puffing technique used to produce crispy textured and nutritious puffed snacks. This study aimed to investigate the effects of freezing at different temperatures (-20 °C, -40 °C, -80 °C) for14 h and freezing times (1 and 2 times) on the cellular structure of purple sweet potato and the quality of RFEP chips. The analysis of cell microstructure, conductivity, and rheology revealed that higher freezing temperatures and more freezing times resulted in increased damage to the cellular structure, leading to greater cell membrane permeability and decreased cell wall stiffness. However, excessive damage to cellular structure caused tissue structure to collapse. Compared with the control group (4 °C), the RFEP sample pre-frozen once at -40 °C had a 47.13 % increase in puffing ratio and a 61.93 % increase in crispness, while hardness decreased by 23.44 % (p < 0.05). There was no significant change in anthocyanin retention or color difference. X-ray microtomography demonstrated that the RFEP sample pre-frozen once at -40 °C exhibited a more homogeneous morphology and uniform pore distribution, resulting in the highest overall acceptability. In conclusion, freezing pre-treatment before RFEP can significantly enhance the puffing quality, making this an effective method for preparing oil-free puffing products for fruits and vegetables.

Effect of blast orientation, multi-point blasts, and repetitive blasts on brain injury

Explosions in the battlefield can result in brain damage. Research on the effects of shock waves on brain tissue mainly focuses on the effects of single-orientation blast waves, while there have been few studies on the dynamic response of the human brain to directional explosions in different planes, multi-point explosions and repetitive explosions. Therefore, the brain tissue response and the intracranial pressure (ICP) caused by different blast loadings were numerically simulated using the CONWEP method. In the study of the blast in different directions, the lateral explosion blast wave was found to cause greater ICP than did blasts from other directions. When multi-point explosions occurred in the sagittal plane simultaneously, the ICP in the temporal lobe increased by 37.8 % and the ICP in the parietal lobe decreased by 17.6 %. When multi-point explosions occurred in the horizontal plane, the ICP in the frontal lobe increased by 61.8 % and the ICP in the temporal lobe increased by 12.2 %. In a study of repetitive explosions, the maximum ICP of the second blast increased by 40.6 % over that of the first blast, and that of the third blast increased by 61.2 % over that of the second blast. The ICP on the brain tissue from repetitive blasts can exceed 200 % of that of a single explosion blast wave.

A systematic review of otologic injuries sustained in civilian terrorist explosions

PURPOSE

Determine the prevalence of otological symptoms and tympanic membrane perforation, healing rates of tympanic membrane perforation with surgical and conservative management, and hearing function in civilian victims of terrorist explosions.

METHODS

A systematic review was conducted with searches on Medline, Embase, EMCare and CINAHL for publications between the 1st January 1945 and 26th May 2023. Studies with quantitative data addressing our aims were included. This review is registered with PROSPERO: CRD42020166768. Among 2611 studies screened, 18 studies comprising prospective and retrospective cohort studies were included.

RESULTS

The percentage of eardrums perforated in patients admitted to hospital, under ENT follow up and attending the emergency department is 69.0% (CI 55.5-80.5%), 38.7% (CI 19.0-63.0%, I2 0.715%) and 21.0% (CI 11.9-34.3%, I2 0.718%) respectively. Perforated eardrums heal spontaneously in 62.9% (CI 50.4-73.8%, I2 0.687%) of cases and in 88.8% (CI 75.9-96.3%, I2 0.500%) of cases after surgery. Common symptoms present within one month of bombings are tinnitus 84.7% (CI 70.0-92.9%, I2 0.506%), hearing loss 83.0% (CI 64.5-92.9%, I2 0.505%) and ear fullness 59.7% (CI 13.4-93.4%, I2 0.719). Symptomatic status between one and six months commonly include no symptoms 57.5% (CI 46.0-68.3%), hearing loss 35.4% (CI 21.8-51.8%, I2 0.673%) and tinnitus 15.6% (CI 4.9-40.0%, I2 0.500%). Within one month of bombings, the most common hearing abnormality is sensorineural hearing loss affecting 26.9% (CI 16.9-40.1%, I2 0.689%) of ears 43.5% (CI 33.4-54.2%, I2 0.500) of people.

CONCLUSION

Tympanic membrane perforation, subjective hearing loss, tinnitus, ear fullness and sensorineural hearing loss are common sequelae of civilian terrorist explosions.

Numerical simulation of rock blasting under different in-situ stresses and joint conditions

High primary rock stress can limit the generation of rock cracks caused by blasting, and blasting usually shows different rock breaking states under different primary rock stress conditions. There are a large number of naturally formed joints in rock mass, due to the limitations of laboratory tests, a numerical model of jointed rock mass was established using LS-DYNA software to investigate the evolution of blasting damage under various in-situ stresses and open joints. In this simulation, using the Lagrange-Euler (ALE) procedure and the equation of state (JWL) that defines explosive materials, the study considered different joint thicknesses (2cm, 4cm, and 6cm), joint angles (0°, 30°, 60°, and 90°), and in-situ stress conditions (lateral stress coefficients of 0.5, 1, and 2, with vertical in-situ stresses of 10MPa and 20MPa), through stress analysis and damage area comparison, the relationship between damage crack propagation and horizontal and vertical stress difference is explored. The research aimed to understand the mechanisms underlying crack initiation and propagation. The results show that: (1) The presence of joints exerts a barrier effect on the expansion and penetration of cracks. When explosion stress waves reach the joint surface, their propagation is impeded, leading to the diffusion of wing cracks at the joint ends. When the lateral stress coefficient and joint angle are the same, an increase in initial in-situ stress results in a reduction in the area of the blasting damage zone. (2) Under the same initial in-situ stress conditions, the area of the blasting damage zone initially increases and then decreases with an increasing joint angle. However, it remains larger than that without a joint, and there exists an optimal angle that maximizes the damage area. In the simulated conditions, the area of damage cracks is greatest when the joint angle is 60° dip angle. (3) The presence of initial in-situ stress has a certain impact on the initiation and expansion of blasting cracks. The degree and nature of this influence are not solely related to the lateral stress coefficient but also depend on the joint's angle and thickness. When in-situ stress is present, the initial in-situ stress field's pressure is not conducive to the initiation and propagation of blasting cracks. However, the existence of a joint has a noticeable guiding and promoting effect on crack propagation, and the pattern of crack propagation is influenced by both joint and in-situ stress conditions.

Neurological Effects of Repeated Blast Exposure in Special Operations Personnel

Exposure to blast overpressure has been a pervasive feature of combat-related injuries. Studies exploring the neurological correlates of repeated low-level blast exposure in career "breachers" demonstrated higher levels of tumor necrosis factor alpha (TNFα) and interleukin (IL)-6 and decreases in IL-10 within brain-derived extracellular vesicles (BDEVs). The current pilot study was initiated in partnership with the U.S. Special Operations Command (USSOCOM) to explore whether neuroinflammation is seen within special operators with prior blast exposure. Data were analyzed from 18 service members (SMs), inclusive of 9 blast-exposed special operators with an extensive career history of repeated blast exposures and 9 controls matched by age and duration of service. Neuroinflammation was assessed utilizing positron emission tomography (PET) imaging with [18F]DPA-714. Serum was acquired to assess inflammatory biomarkers within whole serum and BDEVs. The Blast Exposure Threshold Survey (BETS) was acquired to determine blast history. Both self-report and neurocognitive measures were acquired to assess cognition. Similarity-driven Multi-view Linear Reconstruction (SiMLR) was used for joint analysis of acquired data. Analysis of BDEVs indicated significant positive associations with a generalized blast exposure value (GBEV) derived from the BETS. SiMLR-based analyses of neuroimaging demonstrated exposure-related relationships between GBEV, PET-neuroinflammation, cortical thickness, and volume loss within special operators. Affected brain networks included regions associated with memory retrieval and executive functioning, as well as visual and heteromodal processing. Post hoc assessments of cognitive measures failed to demonstrate significant associations with GBEV. This emerging evidence suggests neuroinflammation may be a key feature of the brain response to blast exposure over a career in operational personnel. The common thread of neuroinflammation observed in blast-exposed populations requires further study.

Modeling and simulation on spontaneous detonation of ammonium nitrate explosive induced by sulfide ores

In this work, the characteristics of the exothermic reaction between ammonium nitrate and sulfide ores were explored using COMSOL Multiphysics. This reaction can cause an increase in temperature within the blast holes of sulfide mines and can potentially induce premature explosions of the explosives. Initially, simulations were conducted to observe temperature variations in blast holes before and after the loading of explosives. Then, the impact of blast hole diameter and initial temperature on the thermal environment was assessed. Subsequent analysis focused on the fluid field's dynamics, examining flow rate changes and the concentration of signature gases produced by the reaction. Additionally, the influence of blast hole diameter on these parameters was evaluated. The results show that the blast hole temperature is positively related to its diameter and initial temperature. When the diameter of the blast hole is 120 mm and 165 mm, a significant change in flow rate is observed, with a trend of being rapidly increased and then rapidly decreased. The production of NH3 is always found to be greater than that of the other two gases. As for NO and SO2, their production is characterized by an approximate ratio of 1:2. The numerical simulation results can provide important theoretical guidance for the spontaneous detonation of blast hole in sulfide mines.

Effect of radio frequency explosion puffing on physicochemical, functional and crystalline properties, and in vitro digestibility of yam flour

Yam flour was modified by radio frequency explosion puffing at different moisture content, puffing temperature, and puffing pressure difference. After puffing, the protein content and lipid content increased by 0.56-1.28 % and 0.23-0.39 %, respectively. Puffing caused the flour granules to aggregate, increasing the thermal transition temperatures and reducing the pasting viscosities, enthalpy, 1047/1022 cm-1 ratio, and relative crystallinity. Puffing reduced the intensity of the infrared spectrum peak at 1641 cm-1 by breaking the hydrogen bonds without changing A-type crystalline structure. Puffing promoted the conversion of random-coil and α-helix protein structure to β-turn and β-sheet. Puffing retarded in vitro digestibility by reducing rapidly digestible starch content by 7.04-11.12 % and rising slowly digestible starch content and resistant starch content by 4.02-4.89 % and 2.77-3.10 %, respectively. Radio frequency explosion puffing altered flour's physicochemical, functional and digestibility properties by destroying the protein structure and promoting the interaction of starch and proteins/lipids.

Impact of the economic crisis, COVID-19 and the Beirut explosion on ophthalmology training in Lebanon: an observational cohort survey-based study

OBJECTIVES

The objective of the study is to investigate the effects of the COVID-19 pandemic, the economic crisis and the Beirut explosion on the training and work of ophthalmology residents and faculty in Lebanon.

DESIGN

This is an observational cohort survey-based research conducted between January and December 2022.

SETTING

The study targeted all ophthalmology residents and core faculty in Lebanon.

PARTICIPANTS

A total of 52 participants, including 27 residents and 25 core faculty members, completed the survey.

PRIMARY OUTCOME MEASURE

Primary outcomes comprised the subjectively reported effect of the three major external stressors on the training and well-being of ophthalmology trainees and educators in Lebanon.

RESULTS

The study found that the majority of ophthalmology residents and core faculty members were significantly affected by the COVID-19 pandemic, Beirut explosion and the economic crisis in Lebanon. Significant percentage reported financial burden, decrease in outpatient and surgical load and educational activities. Furthermore, most participants reported higher levels of stress, anxiety and depression during the time of crises.

CONCLUSIONS

This study emphasises the need to support healthcare professionals during times of crisis, as they are on the frontlines and can experience high levels of stress, anxiety and depression. By providing support and resources to healthcare professionals, they can better cope with the challenges they face and continue to provide essential care to their patients.

Research Application of Laser-induced Shock Wave for Studying Blast-induced Cochlear Injury

The ear is the organ most susceptible to explosion overpressure, and cochlear injuries frequently occur after blast exposure. Blast exposure can lead to sensorineural hearing loss (SNHL), which is an irreversible hearing loss that negatively affects the quality of life. Detailed blast-induced cochlear pathologies, such as the loss of hair cells, spiral ganglion neurons, cochlear synapses, and disruption of stereocilia, have been previously documented. However, determining cochlear sensorineural deterioration after a blast injury is challenging because animals exposed to blast overpressure usually experience tympanic membrane perforation (TMP), which causes concurrent conductive hearing loss. To evaluate pure sensorineural cochlear dysfunction, we developed an experimental animal model of blast-induced cochlear injury using a laser-induced shock wave. This method avoids TMP and concomitant systemic injuries and reproduces the functional decline in the SNHL component in an energy-dependent manner after LISW exposure. This animal model could be a platform for elucidating the pathological mechanisms and exploring potential treatments for blast-induced cochlear dysfunction.

History and investigation of the chemical odors and explosion in the University Avenue sanitary sewer

During the summer of 2022, a fire and explosion occurred in a sanitary sewer tunnel adjacent to the University of Minnesota Twin Cities campus, propelling utility maintenance covers several meters into the air and jeopardizing the safety of the public and emergency responders. The investigation into the explosion highlighted the complex variables involved in the response to sanitary sewer events. This case study outlines current approaches and proposes recommendations for agencies to be better prepared to prevent, detect, and respond to sewer-related incidents in the future. Our recommendations include the following: (1) proactive use of remote volatile organic compound (VOC) and lower explosive limit (LEL) monitoring in sanitary sewer tunnels, especially downstream of waste discharge sites; (2) incident responders should have access to instruments that measure oxygen, LEL, VOC concentration, carbon monoxide, and hydrogen sulfide; (3) better characterization of the relationship between sewer pressurization, elevation profiles, and vapor movement; (4) verification processes for oil/water separators used by industrial facilities discharging into the sanitary sewer system; (5) installation of ventilated or anchored pressure relief utility maintenance covers where allowed by code; and (6) building maintenance protocols that include regular drain flushing to keep drain traps filled. These measures are recommended to protect infrastructure and the health and safety of the public and the responders.

Analysis of characteristics and causes of gas explosion accidents: a historical review of coal mine accidents in China

Objectives This study aimed to provide greater insight into the characteristics of severe and extraordinarily severe gas explosion accidents (SESGEAs). Methods. The study analyzed the accident characteristics and causes of SESGEAs. As an example, we conducted a specialized case analysis using the 24Model (fourth edition) on the recent Baoma coal mine gas explosion. Results. SESGEA data are characterized by greater volatility, with significant differences in the geographical distribution, temporal distribution and attributed characteristics of the accidents. From the accident analysis: chaotic ventilation management was the most serious accident cause of SESGEAs; unsafe acts related to ventilation operations accounted for 18.51% of all unsafe acts; coal miners lack professional safety knowledge and have a serious fluke mentality in mining work; enterprises have insufficient enforcement of safety procedure documents, and lack of attention to the allocation of underground human resources and safety training systems; and the importance of safety, the role of the safety department and satisfaction with safety facilities have become the most serious missing items of safety culture. Conclusion. This study can provide important data support and management basis to assist mine operators in developing more targeted accident prevention strategies.

Lower Extremity Injury Risk Curve Development for a Human Body Model in the Underbody Blast Environment

Computational human body models (HBMs) provide the ability to explore numerous candidate injury metrics ranging from local strain based criteria to global combined criteria such as the Tibia Index. Despite these efforts, there have been relatively few studies that focus on determining predicted injury risk from HBMs based on observed postmortem human subjects (PMHS) injury data. Additionally, HBMs provide an opportunity to construct risk curves using measures that are difficult or impossible to obtain experimentally. The Global Human Body Models Consortium (GHBMC) M50-O v 6.0 lower extremity was simulated in 181 different loading conditions based on previous PMHS tests in the underbody blast (UBB) environment and 43 different biomechanical metrics were output. The Brier Metric Score were used to determine the most appropriate metric for injury risk curve development. Using survival analysis, three different injury risk curves (IRC) were developed: "any injury," "calcaneus injury," and "tibia injury." For each injury risk curve, the top three metrics selected using the Brier Metric Score were tested for significant covariates including boot use and posture. The best performing metric for the "any injury," "calcaneus injury" and "tibia injury" cases were calcaneus strain, calcaneus force, and lower tibia force, respectively. For the six different injury risk curves where covariates were considered, the presence of the boot was found to be a significant covariate reducing injury risk in five out of six cases. Posture was significant for only one curve. The injury risk curves developed from this study can serve as a baseline for model injury prediction, personal protective equipment (PPE) evaluation, and can aid in larger scale testing and experimental protocols.

Risk of burns in pressure cooker usage: a comprehensive analysis of explosive injuries

BACKGROUND

Despite the widespread use of pressure cookers for quick and efficient cooking, literature has insufficiently highlighted the potential dangers resulting from inappropriate handling. This study aims to provide a comprehensive overview of 32 patients who presented with pressure cooker burns, emphasizing the serious risks associated with their misuse.

METHODS

Retrospective data were collected from patients admitted to Bağcılar Training and Research Hospital Burn Center between 2017 and 2020 with pressure cooker burns in Türkiye. Data encompassed patient characteristics, burn causes, locations, severities, treatments, and clinical outcomes.

RESULTS

The study included 32 patients (29 female/3 male) with a mean age of 42.3 (8-83). Patients were categorized based on burn areas, revealing associated injuries such as ocular (34.3%) and ear injuries (6.25%). The average hospital stay was 10.5 days [2-37]. While five pressure cookers exploded due to product-related issues, 26 explosions resulted from user errors (15.6%/81.2%). Importantly, no mortality was observed among the patients.

CONCLUSION

While pressure cookers facilitate rapid food preparation, this study underscores the severe risks arising from product or usage errors. This study emphasizes the need for more effective usage instructions and increased awareness about pressure cookers to prevent burn risks. We anticipate that educational programs focused on safe pressure cooker use could significantly reduce the incidence of serious injuries.

Experimental Study on Intracranial Pressure and Biomechanical Response in Rats Under the Blast Wave

Explosion overpressure propagates extracranially and causes craniocerebral injury after being transmitted into the brain. Studies on the extent of skull to reduce impact overpressure are still lacking. Therefore, it is necessary to study the relationship between intracranial pressure (ICP) and external field pressure and the situation of craniocerebral injury under the blast wave. Pressure sensor of ϕ 1.2 mm was disposed 3 mm posterior to the bregma of rat skull, and type I biological shock tube (BST-I) was used as the source of injury while a side-on air pressure sensor was installed at the horizontal position of the ICP sensor. Eleven groups of blast experiments with peak air overpressure ranging from 167 kPa to 482 kPa were performed to obtain the variation law of ICP and injury of rats. Data measured by sensors show that the peak pressure formed in the rat brain are lower than the external air overpressure; the differential pressure between the inside and outside of the brain is 27-231 kPa. When side-on air overpressure is ≤363 kPa, ICP is ≤132 kPa, and the hemorrhage area of the rat's brain is <15%, the injury is minor. When side-on air overpressure is 363 kPa-401 kPa, ICP range is from 132 kPa to 248 kPa, hemorrhage area is about 15%-20%, and the injury increases. When side-on air overpressure is 401 kPa-435 kPa, ICP range from 248 kPa to 348 kPa, the hemorrhage area is about 20%-24%, and the injury is serious. When side-on air overpressure ≥482 kPa, the peak ICP surged to 455 kPa and the peak negative ICP reached -84 kPa, the hemorrhage area exceeded 26%. When the external blast wave is weak, skull can absorb the blast wave better, reducing the pressure by 81.4%, when the external shockwave is strong, skull only reduces the pressure by 5.6%, but both can play certain protective role. The fitting curve of air overpressure and ICP can be used to predict the changes of ICP under different external blast overpressure. Analysis of cranial injury showed that the area of cranial hemorrhage with extremely severe injury increased by 107.9% compared with mild injury, increased by 53.3% compared with moderate injury, and increased by 21.6% compared with severe injury. This work may provide references for the dynamic response of biological cranial and brain injury mechanism under the effect of blast wave.

Important role of turbulence on the distribution of particle radioactivity in the nuclear explosions

The distribution of particle radioactivity is one of the most important source items of radioactive fallout prediction model for nuclear explosion. For radioactive particles with the diameter larger than 0.5 μm, the influence of turbulent coagulation cannot be ignored. However, few scholars have considered the role of turbulence in the study of the distribution of particle radioactivity. The General Dynamic Equation (GDE), which is solved using the Multi-Monte Carlo method, is used in this study to establish a new model of the distribution of particle radioactivity that takes the impact of turbulent coagulation into account. The results present that the surface and volume distributions of particle radioactivity are closer to those of the Defense Land Fallout Interpretative Code (DELFIC) model, and the relative error of the surface (volume) distribution reduces from 1.243 (0.687) to 0.945 (0.284) when compared to the previous model that simply takes Brownian coagulation into account. The geometric median diameter of total particle radioactivity increases as the solidification temperature increases and as the particle size range increases when considering the influence of various geological conditions. When considering the effects of turbulent coagulation, the differences in the particle radioactivity produced under different geological conditions are smaller than those only considering the Brownian coagulation. This study highlights the importance of turbulent coagulation on the distribution of particle radioactivity in the nuclear explosions.

Evaluating Pelvis Response During Simulated Underbody Blast Loading

In recent conflicts, blast injury from landmines and improvised explosive devices (IEDs) has been the main mechanism of wounding and death. When a landmine or IED detonates under a vehicle (an under-body blast), the seat acceleration rapidly transmits a high load to the pelvis of the occupants, resulting in torso and pelvic injury. Pelvic fractures have high mortality rates, yet their injury mechanism has been poorly researched. Three (3) fresh-frozen male pelvic specimens were tested under axial impact loading. The pelvis was impacted mounted upside down by dropping a 12 kg mass at target impact velocities ranging from 1 to 8.6 m/s with time to peak velocity ranging from 3.8 to 5.8 ms. Resulting fractures were broadly categorized as involving a bilateral pubis rami fracture, a bilateral ischium fracture, and sacroiliac joint disruption. The study provides insights into the type and severity of pelvic injury that may occur over a range of under-body blast (UBB)-relevant loading profiles.

Blast-Induced Central Auditory Neurodegeneration Affects Tinnitus Development Regardless of Peripheral Cochlear Damage

Blast exposure causes serious complications, the most common of which are ear-related symptoms such as hearing loss and tinnitus. The blast shock waves can cause neurodegeneration of the auditory pathway in the brainstem, as well as the cochlea, which is the primary receptor for hearing, leading to blast-induced tinnitus. However, it is still unclear which lesion is more dominant in triggering tinnitus, the peripheral cochlea or the brainstem lesion owing to the complex pathophysiology and the difficulty in objectively measuring tinnitus. Recently, gap detection tests have been developed and are potentially well-suited for determining the presence of tinnitus. In this study, we investigated whether the peripheral cochlea or the central nervous system has a dominant effect on the generation of tinnitus using a blast-exposed mouse model with or without earplugs, which prevent cochlear damage from a blast transmitted via the external auditory canal. The results showed that the earplug (+) group, in which the cochlea was neither physiologically nor histologically damaged, showed a similar extent of tinnitus behavior in a gap prepulse inhibition of acoustic startle reflex test as the earplug (-) group, in which the explosion caused a cochlear synaptic loss in the inner hair cells and demyelination of auditory neurons. In contrast, both excitatory synapses labeled with VGLUT-1 and inhibitory synapses labeled with GAD65 were reduced in the ventral cochlear nucleus, and demyelination in the medial nucleus of the trapezoid body was observed in both groups. These disruptions significantly correlated with the presence of tinnitus behavior regardless of cochlear damage. These results indicate that the lesion in the brainstem could be dominant to the cochlear lesion in the development of tinnitus following blast exposure.

A comparison of fracture response in female and male lumbar spine in simulated under body blast component tests

Underbody blasts (UBB) from mines and improvised explosive devices in military combat can cause debilitating spine injuries to vehicle mounted soldiers. Due to the exclusion of females in combat roles in prior US Department of Defense policy, UBB exposure and injury have predominantly affected male soldiers. Recent policy changes have opened many combat roles to women serving in the US Military (Carter, 2015) and have increased the need to understand the injury potential for female Warfighters. The goal of this study was to investigate the fracture response of adult female lumbar spines compared to adult male spines in UBB relevant loading to identify potential differences in either fracture mechanism or force. Results are presented for 15 simulated UBB spine compression tests using three small female (SF), five large female (LF), and seven mid-sized male (MM) post-mortem human subjects (PMHS). These PMHS groups align to 5th- and 75th-percentile female and 50th-percentile males, based on height and weight from the 2012 Anthropometric Survey of U.S. Army Personnel (Gordon et al., 2014). Both small females and large females (similar in size to the males) were included to assess the role of size and/or sex in the response. Tests were conducted at Virginia Tech on a cam-driven linear compression rig, which included a 6-axis load cell and ram accelerometer to evaluate the fracture. Fracture was visualized through high-speed x-ray video. All female and male spines exhibited similar fracture initiation at the end plates and progression through the vertebral body. The resulting severe compression and burst fractures were representative of reported theatre injuries (Freedman et al., 2014). Mean axial fracture forces were -4182 ± 940 N (SF), -6225 ± 1180 N (LF), -5459 ± 1472 N (All Females) and -7993 ± 2445 N (MM). The SF group was found to have statistically significant differences in mean fracture force compared to both LF and MM groups, while no significant difference was found between LF and MM groups, although the mean force at initial fracture was lower for the LF group. The All-Females group Fz mean was significantly different from the MM group. These data suggest that the significant difference in weight between the SF and LF groups, did have an influence on the Fz outcome, when controlling for sex. Conversely, controlling for size in the LF and MM comparison, sex did influence the mean Fz, but was not statistically significant. Groups with combined sex and size differences, however, did show significant differences in mean Fz. Further study is warranted to understand whether sex or size has a larger effect on fracture force. Mean ram displacement (spine compression) values at fracture initiation were -6.0 ± 5.3 mm (SF), -4.4 ± 0.8 mm (LF), -5.0 ± 3.0 mm (All Females), -6.2 ± 4.5 mm (MM). Spine compression did not seem to be largely influenced by either sex or size, and none of the groups was found to have significant differences in mean displacement values.

Effect of postharvest storage time on quality characteristics of explosion puffing dried whole shiitake mushroom (Lentinula edodes) crisps

BACKGROUND

Non-fried shiitake mushroom (Lentinula edodes) crisps fabricated by explosion puffing drying (EPD) are receiving worldwide attention because of their crispness, convenience, nutrition and health functions. The quality of mushroom crisps varies with storage time of fresh L. edodes. Therefore, the effect of postharvest storage time (ranging from 0 to 14 days) of fresh L. edodes on quality characteristics of EPD- processed mushroom crisps was evaluated.

RESULTS

The weight loss and total color difference of fresh L. edodes were increased to 2.95% and 24.66, but moisture content, firmness and lightness were reduced by 6.14%, 40.70% and 43.57%, respectively, after 14 days storage. The puffing degree of mushroom crisps was initially increased to its highest value (55.95%) on the 4th day storage and thereafter decreased. The highest rehydration ratio (2.36) and crispness (63.67), and lowest hardness (102.95 N) of mushroom crisps were fabricated with L. edodes on the 4th day of storage. Free water was predominant in fresh L. edodes, which was decreased for fresh L. edodes, whereas it increased initially to the maximum value and decreased thereafter for osmotic dehydrated and heat pump pre-dried L. edodes with increasing storage time. Principal component analysis and hierarchical cluster analysis confirmed that fresh L. edodes stored at different times had a remarkable effect on quality characteristics of mushroom crisps.

CONCLUSION

Fresh L. edodes stored at 4 ± 1 °C for 4 days is recommended for fabrication of mushroom crisps with superior quality. This study provides a theoretical basis for selection of a suitable storage time for fresh L. edodes before EPD of crisps. © 2023 Society of Chemical Industry.

Contribution of radioactive particles to the post-explosion exposure of atomic bomb survivors implied from their stable chromosome aberration rates

Even today when nearly 80 years have passed after the atomic bomb (A-bomb) was dropped, there are still debates about the exact doses received by the A-bomb survivors. While initial airborne kerma radiation (or energy spectrum of emitted radiation) can be measured with sufficient accuracy to assess the radiation dose to A-bomb survivors, it is not easy to accurately assess the neutron dose including appropriate weighting of neutron absorbed dose. Particularly, possible post-explosion exposure due to the radioactive particles generated through neutron activation have been almost neglected so far, mainly because of a large uncertainty associated to the behavior of those particles. However, it has been supposed that contribution of such non-initial radiation exposure from the neutron-induced radioactive particles could be significant, according to the findings that the stable chromosomal aberration rates which indicate average whole-body radiation doses were found to be more than 30% higher for those exposed indoors than for those outdoors even at the same initial dose estimated for the Life Span Study. In this Mini Review article, the authors explain that such apparently controversial observations can be reasonably explained by assuming a higher production rate of neutron-induced radioactive particles in the indoor environment near the hypocenter.

Impact of the 4th of August Beirut explosion mass casualty incident on a university hospital microbial Flora

BACKGROUND

Following the Beirut explosion, our university hospital received at least 350 casualties. Subsequently, infection control standard practices were compromised. Concerns for Multi-Drug Resistant Organisms (MDROs) infections in injured patients and a resulting hospital outbreak were raised. The objectives of the study were to compare the rate of hospital growing MDROs 6 months before and 6 months after the Beirut explosion, to identify emerging microorganisms and to evaluate the change in surgical infection prevention practices.

METHODS

This is a retrospective chart review of patients with hospital acquired infections (HAI) admitted to the hospital before and after the Beirut explosion. The study was conducted between February 4, 2020 and January 4, 2021. Excluded patients were those transferred from other hospitals and those with community acquired infections. The primary outcome was to identify the rate of growing MDROs post explosion. The secondary outcomes were identifying antibiotics used for surgical prophylaxis in patients requiring surgeries and patients diagnosed with a HAI. Therefore, patients were divided in three groups. Control group included patients admitted with explosion-related injuries on that same day. Patients admitted and between February 4 and August 4 and diagnosed with HAI were compared to those admitted post August 4 with explosion-related HAI and to patients diagnosed with non-explosion-related HAI between August 4 and January 4, 2021. An estimated rate of 18-22% MDRO was needed to achieve a statistical significance with 80% power and 0.05 α. Pearson Chi square test was used to analyze the primary outcome.

RESULTS

A total of 82 patients with 150 cultures were included in this study. Data showed an increase in the rate of MDRO after the explosion with 37.1% of the cultures taken before the explosion and 53.1% after the explosion (p = 0.05). When comparing the types of HAI in both groups, culture sites were significantly different between pre- and post-explosion patients (p = 0.013). However, both groups had similar types of microbes (p = 0.996) with an increase in candida related infections.

CONCLUSION

These findings confirmed that the Beirut explosion impact on antimicrobial resistance was similar to combat zone incidence, where an increase in MDROs rate such as Escherichia coli (E.Coli) and Stenotrophomonas maltophilia, in addition to the increase in candida related infections.

Blunt force trauma and blast injuries to head and chest caused by a potent pyrotechnic device: a case report

In times of peace and except for terrorist attacks, fatalities by explosions are rare. Fireworks have deadly potential, especially self-made or illegally acquired devices. The use of professional pyrotechnics by untrained persons poses a life-threatening hazard. We present a case of devastating blunt force and blast injuries to the head and chest of a young man. After ignition of a display shell (syn. a real shell or mortar shell) without the use of a launching pipe, the device hit the man's face, nearly simultaneously followed by the explosion of the burst charge. The autopsy revealed injuries to the face and forehead as well as extensive tissue structure damage and a massive contusion with a bloody edema of the lungs. Autopsy results are supplemented with CT imaging and 3D reconstruction of the fractured mid face, as well as histological and toxicological examinations. This case of a misused display shell demonstrates both its devastating destructive potential and the corresponding and rarely observed injury pattern.

Religious coping and levels of posttraumatic stress disorder symptomatology after the Beirut explosion

OBJECTIVE

Religious coping has implications for the development of psychopathology in the aftermath of traumatic events. This study explored the relationship between religious coping (positive and negative) and posttraumatic stress disorder (PTSD) symptomology among survivors of a large industrial explosion that devastated parts of Beirut in August of 2020.

METHOD

Three months after the disaster, 996 residents of Beirut and Lebanon completed validated measures of religious coping (RCOPE) and PTSD symptomatology (Impact of Events Scale-Revised) in either English or Arabic. The majority of participants were young adults aged between 18 and 25 years.

RESULTS

Results indicated that higher levels of negative religious coping were a significant predictor of higher levels of PTSD symptomatology and were associated with a two-fold risk of meeting the criteria for probable PTSD. Other significant predictors included female gender, being a resident of Beirut at the time of the explosion, having personally sustained an injury, or knowing a person injured in the explosion. Effects sizes ranged from .34 to .68.

CONCLUSIONS

Higher scores on measures of negative religious coping were associated with higher levels of PTSD symptomatology. However, negative religious coping may be better construed as a set of religious-based appraisals of event causality and may represent a form of peritraumatic appraisal in the wake of traumatic events. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Prevalence and correlates of mental health difficulties following the beirut port explosion: The roles of mentalizing and resilience

OBJECTIVE

Research has consistently highlighted an increased prevalence of mental health problems, such posttraumatic stress disorder (PTSD), depression, and anxiety, following both man-made and natural disasters. Mentalizing and resilience have been previously identified as potential protective factors against the onset of mental health difficulties following such events.

METHOD

This study first identified the prevalence of PTSD symptoms, depression, anxiety, and stress and subsequently assessed mentalizing abilities and resilience as predictors of PTSD symptomatology in a sample of 521 Lebanese participants following the Beirut Port explosion on August 4, 2020.

RESULTS

Findings were consistent with existing literature highlighting elevated rates of PTSD, depression, and anxiety subsequent to man-made disasters, with higher rates of mental health symptoms observed among women, those with a preexisting diagnosis of psychiatric disorder (1.5 times more likely to meet the PTSD Checklist for DSM-5 [PCL-5] cutoff score), and those who had to move houses (over 2 times more likely to meet PCL-5 cutoff) as a consequence of the explosion. Higher mentalizing capacities were positively correlated with higher resilience scores and lower indices of mental health difficulties. Each unit increase in resilience scores was associated with a 3% reduction in meeting PCL-5 cutoff, and poorer mentalizing abilities was associated with a 2-fold increase in the risk of meeting PCL-5 cutoff.

CONCLUSIONS

Presence of a previous psychiatric diagnosis, having to move houses, lower mentalizing capacities, and lower resilience scores were found to predict elevated PCL-5 scores. Findings are discussed within the framework of recommendations for interventions targeting people affected by traumatic events. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Curcumin alleviates traumatic brain injury induced by gas explosion through modulating gut microbiota and suppressing the LPS/TLR4/MyD88/NF-κB pathway

Gas explosions (GE) are a prevalent and widespread cause of traumatic brain injury (TBI) in coal miners. However, the impact and mechanism of curcumin on GE-induced TBI in rats remain unclear. In this study, we simulated GE-induced TBI in rats and administered curcumin orally at a dose of 100 mg/kg every other day for 7 days to modulate the gut microbiota in TBI rats. We employed 16S rRNA sequencing and LC-MS/MS metabolomic analysis to investigate changes in the intestinal flora and its metabolic profile. Additionally, we utilized ELISA, protein assays, and immunohistochemistry to assess neuroinflammatory signaling molecules for validation. In a rat TBI model, GE resulted in weight loss, pathological abnormalities, and cortical hemorrhage. Treatment with curcumin significantly mitigated histological abnormalities and microscopic mitochondrial structural changes in brain tissue. Furthermore, curcumin treatment markedly ameliorated GE-induced brain dysfunction by reducing the levels of several neuroinflammatory signaling molecules, including neuron-specific enolase, interleukin (IL)-1β, IL-6, and cryptothermic protein 3. Notably, curcumin reshaped the gut microbiome by enhancing evenness, richness, and composition. Prevotella_9, Alloprevotella, Bacilli, Lactobacillales, Proteobacteria, and Gammaproteobacteria were identified as prominent members of the gut microbiota, increasing the linear discriminant analysis scores and specifically enhancing the abundance of bacteria involved in the nuclear factor (NF)-κB signaling pathway, such as Lachnospiraceae and Roseburia. Additionally, there were substantial alterations in serum metabolites associated with metabolic NF-κB signaling pathways in the model group. Curcumin administration reduced serum lipopolysaccharide levels and downregulated downstream Toll-like receptor (TLR)4/myeloid differentiation primary response 88 (MyD88)/NF-κB signaling. Furthermore, curcumin alleviated GE-induced TBI in rats by modulating the gut microbiota and its metabolites. Based on these protective effects, curcumin may exert its influence on the gut microbiota and the TLR4/MyD88/NF-κB signaling pathways to ameliorate GE-induced TBI.

Blast syndrome - pathophysiology, diagnosis and treatment of blast injuries

The incidence of explosions in large agglomerations is high even during peacetime and continues rising. Blast syndrome injuries are complex, with shock wave causing severe injuries of multiple organ systems. In situations with large numbers of injured persons, effective triage allows an early diagnosis and treatment of the highest number of victims. Treatment is challenging, and potentially conflicting therapeutic goals may alternate. This review provides an overview of the pathophysiology of blast injuries, current diagnostic algorithms and therapeutic procedures.

Optimizing Brain Health of United States Special Operations Forces

United States Special Operations Forces (SOF) personnel are frequently exposed to explosive blasts in training and combat. However, the effects of repeated blast exposure on the human brain are incompletely understood. Moreover, there is currently no diagnostic test to detect repeated blast brain injury (rBBI). In this "Human Performance Optimization" article, we discuss how the development and implementation of a reliable diagnostic test for rBBI has the potential to promote SOF brain health, combat readiness, and quality of life.

Ecotoxicological Risk of World War Relic Munitions in the Sea after Low- and High-Order Blast-in-Place Operations

Submerged munitions from World War I and II are threatening human activities in the oceans, including fisheries and shipping or the construction of pipelines and offshore facilities. To avoid unforeseen explosions, remotely controlled "blast-in-place" (BiP) operations are a common practice worldwide. However, after underwater BiP detonations, the toxic and carcinogenic energetic compounds (ECs) will not completely combust but rather distribute within the marine ecosphere. To shed light on this question, two comparable World War II mines in Denmark's Sejerø Bay (Baltic Sea) were blown up by either low-order or high-order BiP operations by the Royal Danish Navy. Water and sediment samples were taken before and immediately after the respective BiP operation and analyzed for the presence of ECs with sensitive GC-MS/MS and LC-MS/MS technology. EC concentrations increased after high-order BiP detonations up to 353 ng/L and 175 μg/kg in water and sediment, respectively, while low-order BiP detonations resulted in EC water and sediment concentrations up to 1,000,000 ng/L (1 mg/L) and >10,000,000 μg/kg (>10 g/kg), respectively. Our studies provide unequivocal evidence that BiP operations in general lead to a significant increase of contamination of the marine environment and ecotoxicological risk with toxic ECs. Moreover, as compared to high-order BiP detonations, low-order BiP detonations resulted in a several 1000-fold higher burden on the marine environment.

Electrostatic precipitator collection efficiency studies using atmospheric radon progeny as aerosol analogs for nuclear explosion radionuclides

Electrostatic precipitation (ESP) is an attractive low-powered collection mechanism for mobile and fixed aerosol detection of radionuclides (RNs) for Nuclear Explosion Monitoring (NEM). Aerosol samplers deployed in the International Monitoring System use a blower to draw air through a filter media to collect particulates. ESP-based samplers collect aerosols without a filter, which can greatly increase volumetric flow capacity per watt of power consumed. ESP-based collectors may be optimized to perform low-power mobile RN collection or to improve the air throughput of existing monitoring stations. This effort describes the use of unknown concentrations of atmospheric RNs to determine the collection efficiency of a compact ESP design. For this analysis, naturally occurring radon progeny are simultaneously collected by a single stage wire-plate ESP and a filter-based sampler with a known collection efficiency. The activity of resulting samples is measured with gamma-spectroscopy and decay corrected for analysis time offsets. RN collection efficiencies are then derived for an experimental survey of ESP operational parameters that influence the ionization, transit, and collection of aerosols. At volumetric flow rates of 1.5-2 CMM, the optimized collection efficiency was calculated as 21±2%, and slower rates around 0.5 CMM resulted in 55 ±5% collection efficiency. The monitoring performance of the ESP-based collector was assessed for a simplified nuclear explosion source term by calculating the minimal detectable concentrations of short-lived fission & activation products. Results of the study suggest that a low-power ESP is feasible for NEM at distances of 100s of km.

Nuclear explosion monitoring network design considerations

Design of an efficient monitoring network requires information on the type and size of releases to be detected, the accuracy and reliability of the measuring equipment, and the desired network performance. This work provides a scientific basis for optimizing or minimizing networks of 133Xe samplers to achieve a desired performance level for different levels of release. The approach of this work varies the density of sampling locations to find optimal location subsets, and to explore the properties of variations of those subsets - how crucial is a specific subset; are substitutions problematic? The choice of possible station locations is arbitrary but constrained to some extent by the location of islands, land masses, difficult topography (mountains, etc.) and the places where infrastructure exists to run and support a sampler. Performance is evaluated using hypothetical releases and atmospheric transport models that cover an entire year. Three network performance metrics are calculated: the probability of detecting the releases, the expected number of stations to detect the releases, and the expected number of samples that detect the releases. The quantitative measures support picking optimal or near-optimal network of a specific station density. If a detection probability of 90% (high) was desired for a design basis release of 1014 Bq (1% of 133Xe production from a 1 kt explosion), then a very high density would be required using today's sampling and measurement technology. If the design basis release were raised to 1015 Bq, then the station density could be lowered by a factor of 3. To achieve a location goal of three station detections on average, posited here for the first time, would also require very high station density for a release of 1014 Bq.

E-cigarette explosion injuries in the oral and maxillofacial region and a protocol for their management

DATA SOURCES

MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Central Register of Controlled Trials, Embase and Web of Science along with the reference lists from select articles.

STUDY SELECTION

Retrospective or prospective cohort studies, randomised controlled trials, case series, case-control studies and case reports on e-cigarette explosion-related facial injuries published in the English language were included. Review articles, nonclinical studies, commentaries, published abstracts and editorials were excluded. Also were excluded, those studies which did not specify injury location or if the injury did not pertain to the maxillofacial region.

DATA EXTRACTION AND SYNTHESIS

Data pertaining to bibliographic information, device characteristics, patient details, facial injuries, factors precipitating explosion, complications at follow-up, management and other injuries were extracted. An association between the predictor variables of injury type and location with outcomes of surgical management and intubation was determined by utilising a Chi-squared analysis.

RESULTS

A total of 28 studies met the inclusion criteria. A total of 105 facial injuries in 32 patients from 32 e-cigarette explosions were recorded. 73.3% of the injuries were projectile in nature with 26.7% being characterised by burns. 43.8% of all patients suffered both burn and projectile injuries. The eye (10.7%), oral cavity (25%) and face (64.3%) were involved with burn injuries. Projectile injuries mostly involved the lower third of the face (81.8%). 62.5% of patients suffered from a tooth or bone fracture. A 44.4% rate of complications was reported amongst the studies which reported on follow-ups. Surgical management or intubation were found to have no statistically significant relationship with explosive oral injuries. No other statistically significant associations were observed between outcomes and other injury types.

CONCLUSIONS

There is a risk of spontaneous combustion with e-cigarettes, which can cause injuries of a serious nature to the oral and maxillofacial region, specially the lower third of the face, commonly necessitating surgical management. Increased regulation along with user education are required in order to improve the safety profile of these devices.

Computational assessment of leg response to extreme loadings using a detailed finite element model

This study focuses on evaluating the response of the Total Human Model for Safety™ lower extremity finite element model under blast loading. Biofidelity of the lower extremity model was evaluated against experiments with impact loading equivalent to underbody blast. The model response was found to match well with the experimental data for the average impactor speeds of 7 and 9.3 m/s resulting in an overall correlation and analysis rating of 0.86 and 0.82, respectively. The model response was then used to investigate response for antipersonnel mine explosion where the numerical setup consists of a charge mass of 40 g trinitrotoluene placed at a depth of 50 mm below the heel. The explosion was modeled using Multi Material-Arbitrary Lagrangian Eulerian method. The model was subjected to the graded input in terms of variation in standoff distance and mass of explosive to investigate the sensitivity of the model. The model found sensitive to the threat definition and predicted an increase of 110% in peak fluid-structure interaction force with 20% reduction in its time to peak and 29% increase in peak calcaneus axial force with a reduction of 33% in its time to peak when explosive mass varied from 40 g to 100 g. The location of the explosive below the foot was discovered to have significant effect on the injury pattern in near-field explosion. A comparative study suggested that the model predicted similar response and damage pattern compared to experimental data.

Characteristics and mechanism of lower limb injury induced by landmine blast: A research in a rabbit model

BACKGROUND

Limb injuries caused by landmine explosions are tricky to treat and difficult to protect. It is necessary to establish an animal model for studying lower limb injury and to investigate the characteristics and mechanisms of lower limb injury induced by landmine blasts.

METHODS

Twenty-six mature white rabbits were randomly divided into sham group (n=10) and injury group (n=16). Landmine blast was simulated by electric detonators under the right lower limb in upright state by a special modified fixation frame. High-speed photography was used to observe the body movements. Vital signs, vascular injury (determining by digital subtraction angiography), pathological characteristics, and ATP concentration of the tibialis anterior muscle and triceps surae of shank were recorded for com-parison.

RESULTS

Generally, middle and lower segment of the injured legs of the rabbits was seriously damaged. The limb stump presents a distribution of three areas, tissue free zone, contusion hematoma, and edema contusion. Sneak wound track, myofascial destruction, and periosteum stripping were typical characteristics of landmine blast injury. ATP concentration and pathological analysis showed that the tibialis anterior muscle was the most seriously injured, followed by the gastrocnemius and soleus. ATP concentration of affected muscle of both the contusion and commotio area declined remarkably over time, but the muscle in the avulsion area stayed at a low activity level with no change over the time. Small vascular injury in the contusion area was evident. The site of the sciatic nerve lesion was higher than the muscle. Injured site of sciatic nerve injury was higher than serious contusion muscle. High-speed photography demonstrated that the joints of the injured limb extremely flexed followed by a rapid stretch under the blast shock wave.

CONCLUSION

The established experimental model presents typical effect of lower limbs wounded by the mine blast in war field. Landmine blast can cause typical damage on lower limbs including nerve lesion, knee injury, and microcirculation damage that is pro-gressive over time. The limb stump is divided into three zones based on gross pathology and micropathology, which can provide an important reference for clinical treatments and prognosis.

Beirut Port Blast 2020: New Lessons Learned in Mass Casualty Incident Management in the Emergency Department

BACKGROUND

On August 4, 2020, Lebanon suffered its largest mass casualty incident (MCI) to date: the Beirut Port blast. Hospital emergency response to MCIs is particularly challenging in low- and middle-income countries, where emergency medical services are not well developed and where hospitals have to rapidly scale up capacity to receive large influxes of casualties. This article describes the American University of Beirut Medical Center (AUBMC) response to the Beirut Port blast and outlines the lessons learned.

DISCUSSION

The Beirut Port blast reinforced the importance of proper preparedness and flexibility in managing an MCI. Effective elements of AUBMC's MCI plan included geographic-based activation criteria, along with use of Wi-Fi messaging systems for timely notification of disaster teams. Crowd control through planned facility closures allowed medical teams to focus on patient care. Pre-identified surge areas with prepared disaster cart deployment allowed the teams to scale up quickly. Several challenges were identified related to electronic medical records (EMRs), including patient registration, staff training on EMR disaster modules, and cumbersome EMR admission process workflows. Finally, this experience highlights the importance of psychological debriefs after MCIs.

CONCLUSIONS

Hospital MCI preparedness plans can integrate several strategies that are effective in quickly scaling up capacity to respond to large MCIs. These are especially necessary in countries that lack coordinated prehospital systems.

Injury modelling for strategic planning in protecting the national infrastructure from terrorist explosive events

Terrorist events in the form of explosive devices have occurred and remain a threat currently to the population and the infrastructure of many nations worldwide. Injuries occur from a combination of a blast wave, energised fragments, blunt trauma and burns. The relative preponderance of each injury mechanism is dependent on the type of device, distance to targets, population density and the surrounding environment, such as an enclosed space, to name but a few. One method of primary prevention of such injuries is by modification of the environment in which the explosion occurs, such as modifying population density and the design of enclosed spaces. The Human Injury Predictor (HIP) tool is a computational model which was developed to predict the pattern of injuries following an explosion with the goal to inform national injury prevention strategies from terrorist attacks. HIP currently uses algorithms to predict the effects from primary and secondary blast and allows the geometry of buildings to be incorporated. It has been validated using clinical data from the '7/7' terrorist attacks in London and the 2017 Manchester Arena terrorist event. Although the tool can be used readily, it will benefit from further development to refine injury representation, validate injury scoring and enable the prediction of triage states. The tool can assist both in the design of future buildings and methods of transport, as well as the situation of critical emergency services required in the response following a terrorist explosive event. The aim of this paper is to describe the HIP tool in its current version and provide a roadmap for optimising its utility in the future for the protection of national infrastructure and the population.

[Neurobehavioral effects of explosion exposure on acute and chronic traumatic brain injury in rats]

Objective: To explore the effect of nerve injury in rats by neurobehavioral experiments, in order to provide a model and idea for further clarification of the traumatic brain injury mechanism under explosion exposure. Methods: From May 2021 to August 2022, 160 SPF male rats were randomly divided into four groups, including control group, 60 kPa group (low intensity group), 90 kPa group (medium intensity group) and 120 kPa group (high intensity group). The blast induced traumatic brain injury (bTBI) model of rats was established by using the shock tube platform to simulate the shock wave parameters of the explosion overpressure of 60 kPa, 90 kPa and 120 kPa. Acute observation was carried out after 24 h and 7 d of explosive exposure, and chronic recovery observation was carried out after 28 d and 90 d. The time effect of shock wave brain injury in different situations was discussed by open field, light dark test, active avoidance test. Finally, the results of brain injury in rats were detected by pathological tissue staining. Results: After 24 h explosion exposure, compared with the control group, the rest time of rats in low and high intensity groups increased, the total movement distance decreased, and the number of visits to the camera obscura decreased, with statistical significance (P<0.05). After 7 days of exposure, compared with the control group, the rest time of rats in high intensity group increased, and the number of visits to the obscura decreased, with statistical significance (P<0.05). After 28 and 90 days of exposure, compared with the control group, there were no significant differences in rest time, total exercise distance and times of visiting the camera obscura in all intensity groups (P>0.05). After 24 h of explosive exposure, compared with the control group, the cell morphology of rats in each intensity group was normal, and no inflammatory cell infiltration was observed. Conclusion: In the acute phase (24 h) of blast exposure, rats have no desire to explore the outside world, and shock wave exposure may damage the neurological function of rats.

Pelvis-Sacrum-Lumbar Spine Injury Characteristics From Underbody Blast Loading

INTRODUCTION

Combat-related injuries from improvised explosive devices occur commonly to the lower extremity and spine. As the underbody blast impact loading traverses from the seat to pelvis to spine, energy transfer occurs through deformations of the combined pelvis-sacrum-lumbar spine complex, and the time factor plays a role in injury to any of these components. Previous studies have largely ignored the role of the time variable in injuries, injury mechanisms, and warfighter tolerance. The objective of this study is to relate the time or temporal factor using a multi-component, pelvis-sacrum-lumbar spinal column complex model.

MATERIALS AND METHODS

Intact pelvis-sacrum-spine specimens from pre-screened unembalmed human cadavers were prepared by fixing at the superior end of the lumbar spine, pelvis and abdominal contents were simulated, and a weight was added to the cranial end of the fixation to account for torso effective mass. Prepared specimens were placed on the platform of a custom vertical accelerator device and aligned in a seated soldier posture. An accelerometer was attached to the seat platen of the device to record the time duration to peak velocity. Radiographs and computed tomography images were used to document and associate injuries with time duration.

RESULTS

The mean age, stature, weight, body mass index, and bone density of 12 male specimens were as follows: 65 ± 11 years, 1.8 ± 0.01 m, 83 ± 13 kg, 27 ± 5.0 kg/m2, and 114 ± 21 mg/cc. They were equally divided into short, medium, and long time durations: 4.8 ± 0.5, 16.3 ± 7.3, and 34.5 ± 7.5 ms. Most severe injuries associated with the short time duration were to pelvis, although they were to spine for the long time duration.

CONCLUSIONS

With adequate time for the underbody blast loading to traverse the pelvis-sacrum-spine complex, distal structures are spared while proximal/spine structures sustain severe/unstable injuries. The time factor may have implications in seat and/or seat structure design in future military vehicles to advance warfighter safety.

Comparison of Biomechanical Outcome Measures From Characteristically Different Blast Simulators and the Influence of Exposure Location

INTRODUCTION

Simulation of blast exposure in the laboratory has been inconsistent across laboratories. This is primarily because of adoption of the shock wave-generation techniques that are used in aerodynamic tests as opposed to application of blast exposures that are relevant to combat and training environments of a Warfighter. Because of the differences in blast signatures, characteristically different pathological consequences are observed among the preclinical studies. This is also further confounded by the varied exposure positioning of the animal subject (e.g., inside the blast simulator vs. at the mouth of the simulator). In this study, we compare biomechanical responses to blast exposures created in an advanced blast simulator (ABS) that generates "free-field"-like blast exposure with those produced by a traditionally applied cylindrical blast simulator (CBS) that generates a characteristically different blast signature. In addition, we have tested soft-armor vest protective responses with the ABS and CBS to compare the biomechanical responses to this form of personal protective equipment in each setting in a rodent model.

MATERIALS AND METHODS

Anesthetized male Sprague-Dawley rats (n = 6) were surgically probed with an intrathoracic pressure (ITP) transducer and an intracranial pressure (ICP) transducer directed into the lateral cerebral ventricle (Millar, Inc.). An ABS for short-duration blast or a CBS for long-duration blast was used to expose animals to an incident blast overpressure of 14.14 psi (impulse: 30.27 psi*msec) or 16.3 psi (impulse: 71.9 psi*msec) using a custom-made holder (n = 3-4/group). An external pitot probe located near the animal was used to measure the total pressure (tip) and static gauge (side-on) pressure. Data were recorded using a TMX-18 data acquisition system (AstroNova Inc.). MATLAB was used to analyze the recordings to identify the peak amplitudes and rise times of the pressure traces. Peak ICP, peak ITP, and their impulses were normalized by expressing them relative to the associated peak static pressure.

RESULTS

Normalized impulse (ABS: 1.02 ± 0.03 [vest] vs. 1.02 ± 0.01 [no-vest]; CBS: 1.21 ± 0.07 [vest] vs. 1.01 ± 0.01 [no-vest]) and peak pressure for ICP (ABS: 1.03 ± 0.03 [vest] vs. 0.99 ± 0.04 [no-vest]; CBS: 1.06 ± 0.08 [vest] vs. 1.13 ± 0.06 [no-vest]) remained unaltered when comparisons are made between vest and no-vest groups, and the normalized peak ITP (ABS: 1.50 ± 0.02 [vest] vs. 1.24 ± 0.16 [no-vest]; CBS: 1.71 ± 0.20 [vest] vs. 1.37 ± 0.06 [no-vest]) showed a trend of an increase in the vest group compared to the no-vest group. However, impulses in short-duration ABS (0.94 ± 0.06 [vest] vs. 0.92 ± 0.13 [no-vest]) blast remained unaltered, whereas a significant increase of ITP impulse (1.21 ± 0.07 [vest] vs. 1.17 ± 0.01 [no-vest]) in CBS was observed.

CONCLUSIONS

The differences in the biomechanical response between ABS and CBS could be potentially attributed to the higher dynamic pressures that are imparted from long-duration CBS blasts, which could lead to chest compression and rapid acceleration/deceleration. In addition, ICP and ITP responses occur independently of each other, with no evidence of thoracic surge.

Recommendations for a Military Health System Auditory Blast Injury Prevention Standard

INTRODUCTION

Although existing auditory injury prevention standards benefit warfighters, the Department of Defense could do more to understand and address auditory injuries (e.g., hearing loss, tinnitus, and central processing deficits) among service members. The Blast Injury Prevention Standards Recommendation (BIPSR) Process is designed to address the needs of all the Military Services for biomedically valid Military Health System (MHS) Blast Injury Prevention Standards.

MATERIALS AND METHODS

Through the BIPSR Process, stakeholders provided their intended uses and requested functionalities for an MHS Blast Injury Prevention Standard. The BIPSR Process established a broad-based, non-advocacy panel of auditory injury Subject Matter Expert (SME) Panel with members drawn from industry, academia, and government. The SME Panel selected evaluation factors, weighted priorities, and then evaluated the resulting candidate MHS Auditory Blast Injury Prevention Standards against the evaluation criteria. The SME Panel members provided rationales for their decisions, documented discussions, and used iterative rounds of feedback to promote consensus building among members. The BIPSR Process used multi-attribute utility theory to combine members' evaluations and compare the candidate standards.

RESULTS

The SME Panel identified and collated information about existing auditory injury datasets to identify gaps and promote data sharing and comprehensive evaluations of standards for preventing auditory blast injury. The panel evaluated the candidate standards and developed recommendations for an MHS Blast Injury Prevention Standard.

CONCLUSIONS

The BIPSR Process illuminated important characteristics, capabilities, and limitations of candidate standards and existing datasets (e.g., limited human exposure data to evaluate the validity of injury prediction) for auditory blast injury prevention. The evaluation resulted in the recommendation to use the 8-hour Equivalent Level (LAeq8hr) as the interim MHS Auditory Blast Injury Prevention Standard while the community performs additional research to fill critical knowledge gaps.

Impact of Blast Overpressure on the Pharmacokinetics of Various Antibiotics in Sprague Dawley Rats

INTRODUCTION

Combat injuries are complex and multimodal. Most injuries to the extremities occur because of explosive devices such as improvised explosive devices. Blast exposure dramatically increases the risk of infection in combat wounds, and there is limited available information on the best antibiotic treatments for these injuries. We previously demonstrated that mice exposed to blast displayed a delayed clearance of cefazolin from the plasma and liver; further semi-mechanistic modeling determined that cefazolin concentrations in the skin of these mice were reduced. Our objective was to investigate the effects of blast on the pharmacokinetics of antibiotics of different types used for the treatment of combat wounds in the rat model.

MATERIALS AND METHODS

Male Sprague Dawley rats were exposed to blast overpressure followed by injection of a bolus of animal equivalent doses of an antibiotic (cefazolin, cefepime, ertapenem, or clindamycin) into the tail vein at 1-hour post-blast exposure. Blood was collected at predetermined time points via repeated sampling from the tail vein. Animals were also euthanized at predetermined time points, at which time liver, kidney, skin, and blood via cardiac puncture were collected. Antibiotic concentrations were determined by ultra-performance liquid chromatography-tandem mass spectrometry.

RESULTS

Blast-exposed rats exhibited a similar rate of clearance compared to non-blasted rats in the blood, liver, kidney, and skin, which is inconsistent with the data regarding cefazolin in blast-exposed mice.

CONCLUSIONS

Our results in rats do not recapitulate our previous observation of delayed cefazolin clearance in mice following the blast overpressure exposure. Although using rats permitted us to collect multiple blood samples from the same animals, rats may not be a suitable model for measuring the pharmacokinetics of antibiotics following blast. The interpretation of the results may be challenging because of variation in data among rat subjects in the same sample groups.

Fiscal Year 2018 National Defense Authorization Act, Section 734, Weapon Systems Line of Inquiry: Overview and Blast Overpressure Tool-A Module for Human Body Blast Wave Exposure for Safer Weapons Training

INTRODUCTION

Experiences by service members in recent conflicts and training environments illuminate concerns about the possible effects of blast overpressure (BOP) exposure on brain health. Section 734 of the National Defense Authorization Act for Fiscal Year (FY) 2018 (Public Law 115-91) requires that the Secretary of Defense conducts a longitudinal medical study on blast pressure exposure of members of the Armed Forces during combat and training, and the Assistant Secretary of Defense for Health Affairs was assigned responsibility for fulfilling requirements. The study's goal is to improve DoD's understanding of the impact of BOP exposure from weapon systems on service members' brain health and inform policy for risk mitigation, unit readiness, and health care decisions. This article focuses on the activities of the Weapon Systems Line of Inquiry (LOI) and the development of a prototype BOP Tool.

MATERIALS AND METHODS

The DoD established the Section 734 Workgroup, which developed a program structure with five LOIs. The Weapon Systems LOI coordinated, collated, and analyzed information on BOP resulting from heavy weapons and blast events to inform strategies, and accounted for emerging research on health effects and performance. Ongoing research was leveraged to develop a BOP Tool as a standalone module and for integration into the Range Managers Toolkit.

RESULTS

The effort identified opportunities for the DoD to improve the clarity of communications about BOP exposure, risk, and safety; establish methods to leverage emerging research; and develop a prototype BOP Tool to predict exposure loads when firing heavy weapons in training.

CONCLUSIONS

It is recommended that the DoD revises requirements and policy to improve and standardize safety guidance throughout research, development, testing, and evaluation; acquisition; and training. The validated BOP Tool allows users to generate a scenario to predict BOP exposure and allows service members to modify them during planning for safer training.

Development of the Blast Ordnance and Occupational Exposure Measure for Self-Reported Lifetime Blast Exposures

INTRODUCTION

To address the military gap in the standardized collection of lifetime blast exposures across clinical and research endeavors, researchers at the National Intrepid Center of Excellence (NICoE) completed a quality improvement project that utilized systematic, iterative focus groups that leveraged the input from various stakeholders including subject matter experts, clinical providers, and service members (SMs) to develop a comprehensive, self-report blast exposure inventory that could be completed within 5-10 minutes. This manuscript outlines the process of the development of this inventory.

MATERIALS AND METHODS

This project included three phases of focus groups that occurred at the NICoE between August 2020 and March 2021 to collect feedback and input from relevant military stakeholders. The study team utilized related assessments available in the literature, together with clinical experience with the NICoE patient population, to inform the development of an initial draft inventory. Phase 1 consisted of blast injury research subject matter experts who had extensive experience researching and providing clinical care to SMs exposed to blast. Phase 2 consisted of NICoE clinicians across numerous clinical specialties. Phase 3 included current active duty patients in the NICoE intensive outpatient program.

RESULTS

Following completion of the focus groups, a lifetime blast exposure inventory was developed in the form of a single page table including incoming, outgoing, training, and operational exposures and broken down by levels of weapon systems as well as breaching and explosive ordnance disposal exposures. In addition, select questions related to the first and most recent blast exposures and experience as an instructor for explosive ordnance disposal- and breaching-related training were included.

CONCLUSIONS

Researchers at the NICoE developed a self-report blast exposure inventory through a quality improvement project that included active, ongoing participation and feedback of clinical experts and military SMs. The end result is a brief, single page inventory that can be administered within 5-10 minutes. Although additional research is needed to refine and validate the inventory, the project team believes that the tool begins to address a long-standing gap in the DoD in the standardized collection of lifetime blast exposures.

Comparison of Axial Force Attenuation Characteristics in Two Different Lower Extremity Anthropomorphic Test Devices

INTRODUCTION

Any type of boot or footwear is designed to attenuate and distribute loading to the bottom of the foot. Anthropomorphic test device (ATDs) are used to assess potential countermeasures against these loads. The specific aims of this study were to compare and quantify force attenuation characteristics as a function of input energy for Hybrid-III and Mil-Lx ATD human surrogates.

MATERIALS AND METHODS

Two lower leg ATD surrogates (Mil-Lx and Hybrid-III) were tested to investigate the influence of a commercially available military boot on lower extremity force response and assess such differences against previously published postmortem human surrogate studies. The testing apparatus impacted the bottom of the foot using a rigid plate at velocities from 2 to 10 m/s. Tests were conducted on each ATD to obtain axial force response with and without boots as a function of input energy.

RESULTS

Peak forces ranged from 1 to 16.4 kN for the Hybrid-III, and 1 to 8.4 kN for the Mil-Lx for similar input conditions. The average force attenuation for the Hybrid-III at upper and lower load cells was 71% (59%-80%) and 70% (58%-78%). The average attenuation for the Mil-Lx at upper and lower load cells was 20% (13%-28%) and 37% (36%-37%), respectively. At the knee load cell, the attenuated peak loads ranged from 62% to 81% for the Hybrid-III and 16% to 30% for the Mil-Lx.

CONCLUSIONS

Force attenuation characteristics in the booted vs unbooted configuration of the Mil-Lx were significantly different than force attenuation characteristics of the H3 and may better represent in vivo forces during vertical impact injuries, such as IED blasts. Hence for military relevant applications where boots are used, the Mil-Lx may provide a more conservative evaluation of lower extremity protection systems.