Protective performance of helmets and goggles in mitigating brain biomechanical response to primary blast exposure.

The current combat helmets are primarily designed to mitigate blunt impacts and ballistic loadings. Their protection against primary blast wave is not well studied. In this paper, we comprehensively assessed the protective capabilities of the advanced combat helmet and goggles against blast waves with different intensity and directions. Using a high-fidelity human head model, we compared the intracranial pressure (ICP), cerebrospinal fluid (CSF) cavitation, and brain strain and strain rate predicted from bare head, helmet-head and helmet-goggles-head simulations. The helmet was found to be effective in mitigating the positive ICP (24-57%) and strain rate (5-34%) in all blast scenarios. Goggles were found to be effective in mitigating the positive ICP in frontal (6-16%) and lateral (5-7%) blast exposures. However, the helmet and goggles had minimal effects on mitigating CSF cavitation and even increased brain strain. Further investigation showed that wearing a helmet leads to higher risk of cavitation. In addition, their presence increased the head kinetic energy, leading to larger strains in the brain. Our findings can improve our understanding of the protective effects of helmets and goggles and guide the design of helmet pads to mitigate brain responses to blast

Optimization of the chin bar of a composite-shell helmet to mitigate the upper neck force

The chin bar of motorcycl e full - face helmets is the most likely region of the helmet to sustain impact s during accident s , with a large percentage of these impacts lead ing to basilar skull fracture . Currently, helmet chin bars are designed to mitigate the peak acceleration at the c entre o f g ravity of isolated headforms , as required by standards, but they are not designed to mitigate the neck force, which is probably the cau se of basilar skull fracture, a type of head injury that can lead to fatalities . Here we test whether it is possible to increase the protection of helmet chin bars while meeting standard requirements. Fibre - reinforced composite shells are commonly used in helmets due to their lightweight and energy absorption charac teristics. W e optimize the ply orientation of a chin bar made of fibre - reinforced composite layers for reduction of the neck force in a dummy model using a computational approach . We use the fini te element model of a human head/neck surrogate and measure the neck axial force, which has been shown to be correlated with the risk of basilar skull fracture. The results show t hat by varying the orientation of the chin bar plies , thus keeping the helmet mass constant, the neck axial force can be reduced by approximately 3 0 % while ensuring that the helmet complies with the impact attenuation requirements prescribed in helmet standards

In-depth bicycle collision reconstruction: from a crash helmet to brain injury evaluation

Traumatic brain injury (TBI) is a prevalent injury among cyclists experiencing head collisions. In legal cases, reliable brain injury evaluation can be difficult and controversial as mild injuries cannot be diagnosed with conventional brain imaging methods. In such cases, accident reconstruction may be used to predict the risk of TBI. However, lack of collision details can render accident reconstruction nearly impossible. Here, we introduce a reconstruction method to evaluate the brain injury in a bicycle–vehicle collision using the crash helmet alone. Following a thorough inspection of the cyclist’s helmet, we identified a severe impact, a moderate impact and several scrapes, which helped us to determine the impact conditions. We used our helmet test rig and intact helmets identical to the cyclist’s helmet to replicate the damage seen on the cyclist’s helmet involved in the real-world collision. We performed both linear and oblique impacts, measured the translational and rotational kinematics of the head and predicted the strain and the strain rate across the brain using a computational head model. Our results proved the hypothesis that the cyclist sustained a severe impact followed by a moderate impact on the road surface. The estimated head accelerations and velocity (167 g, 40.7 rad/s and 13.2 krad/s2) and the brain strain and strain rate (0.541 and 415/s) confirmed that the severe impact was large enough to produce mild to moderate TBI. The method introduced in this study can guide future accident reconstructions, allowing for the evaluation of TBI using the crash helmet only

Smoothed particle hydrodynamic modelling of the cerebrospinal fluid for brain biomechanics: accuracy and stability

The Cerebrospinal Fluid (CSF) can undergo shear deformations under head motions. Finite Element (FE) models, which are commonly used to simulate biomechanics of the brain, including traumatic brain injury, employ solid elements to represent the CSF. However, the limited number of elements paired with shear deformations in CSF can decrease the accuracy of their predictions. Large deformation problems can be accurately modelled using the mesh-free Smoothed Particle Hydrodynamics (SPH) method, but there is limited previous work on using this method for modelling the CSF. Here we explored the stability and accuracy of key modelling parameters of an SPH model of the CSF when predicting relative brain/skull displacements in a simulation of an in vivo mild head impact in human. The Moving Least Squares (MLS) SPH formulation and Ogden rubber material model were found to be the most accurate and stable. The strain and strain rate in the brain differed across the SPH and FE models of CSF. The FE mesh anchored the gyri, preventing them from experiencing the level of strains seen in the in vivo brain experiments and predicted by the SPH model. Additionally, SPH showed higher levels of strains in the sulci compared to the FE model. However, tensile instability was found to be a key challenge of the SPH method, which needs to be addressed in future. Our study provides a detailed investigation of the use of SPH and shows its potential for improving the accuracy of computational models of brain biomechanics

A case of white eye syndrome in cultured whiteleg shrimp (Litopenaeus vannamei) in concrete ponds

A month after movement of 1800 pieces of L. vannamei (average weight of 16g) from culture ponds in Heleh region to concrete ponds of Bandargah hatchery (Bushehr province) some shrimps showed symptoms such as decrease in growth rate, loss of appetite, dark pigmentation of cuticle and presence of black foci on it, redness of uropods and white, irregular and circular spots on the eye with 2-5mm diameters. For detection of etiological agent samples were taken for PCR, bacteriological and histo-pathological tests. Nested PCR test using IQ2000 kits for detection of major shrimp viral pathogens (IHHNV, WSSV, YHV and TSV) were conducted and all results were negative. In histo-pathological tests, lesions in eyes were liquefactive necrosis of cone cells and cone crystals with infiltration of hemocyte and formation of micro abscess in the diapteric region of eye. In bacteriological tests, a gram negative pleomorphic bacterium of the genus Aeromonas was isolated. However, it seems that this bacterium is the secondary agent and for detection of the primary agent more research is needed

A review of cyclist head injury, impact characteristics and the implications for helmet assessment methods

Head injuries are common for cyclists involved in collisions. Such collision scenarios result in a range of injuries, with different head impact speeds, angles, locations, or surfaces. A clear understanding of these collision characteristics is vital to design high fidelity test methods for evaluating the performance of helmets. We review literature detailing real-world cyclist collision scenarios and report on these key characteristics. Our review shows that helmeted cyclists have a considerable reduction in skull fracture and focal brain pathologies compared to non-helmeted cyclists, as well as a reduction in all brain pathologies. The considerable reduction in focal head pathologies is likely to be due to helmet standards mandating thresholds of linear acceleration. The less considerable reduction in diffuse brain injuries is likely to be due to the lack of monitoring head rotation in test methods. We performed a novel meta-analysis of the location of 1809 head impacts from ten studies. Most studies showed that the side and front regions are frequently impacted, with one large, contemporary study highlighting a high proportion of occipital impacts. Helmets frequently had impact locations low down near the rim line. The face is not well protected by most conventional bicycle helmets. Several papers determine head impact speed and angle from in-depth reconstructions and computer simulations. They report head impact speeds from 5 to 16 m/s, with a concentration around 5 to 8 m/s and higher speeds when there was another vehicle involved in the collision. Reported angles range from 10° to 80° to the normal, and are concentrated around 30°-50°. Our review also shows that in nearly 80% of the cases, the head impact is reported to be against a flat surface. This review highlights current gaps in data, and calls for more research and data to better inform improvements in testing methods of standards and rating schemes and raise helmet safety

Relationship of Spirituality and Quality of Life in Patients with Type 2 diabetes

Diabetes and its complications have a significant impact on patients' quality of life and spirituality can help improve the quality of life in such patients. The purpose of this study was to determine the relationship of spirituality with quality of life in patients with Type 2 diabetes. Materials and Methods: This was a descriptive-correlation study. Participants were 145 individuals with type 2 diabetes, patients of rural health clinics and the Valiasr hospital in Khorramshahr city, selected via stratified random and sampling methods. Data collection tools were a version of 29-item of the spiritual questionnaire (Parsian and Dunning) and a version of 26-item of the Quality of Life Questionnaire (World Health Organization), both questionnaires with previously confirmed validity and reliability in numerous studies. Data were analyzed using SPSS version 16 software and Pearson's correlation, T-test, ANOVA, Post Hoc and Stepwise Regression analytical statistics. Results: There was a significant positive relationship between spirituality and quality of life (p<0.0001). The results show a statistically significant relationship between spirituality and quality of life with both education and age. Conclusion: A strong correlation between spirituality and quality of life in patients with type II diabetes, demonstrates the roles and responsibilities of healthcare providers, including physicians, nurses and patients' families in meeting the varied spiritual and religious needs of patients along with their therapeutic management. Focusing on improving spiritual health is also important in education programs for these patients

Prevalence rate of white spot syndrome virus (WSSV) in farmed white leg shrimp (Litopenaeus vannamei) in Bushehr province

We surveyed presence of white spot syndrome virus (WSSV) in farmed white leg shrimp in Bushehr province with assumed a prevalence of 2% of virus in target population. Hence, 468 samples were collected in two separate phases from May to October 2006. In the first phase, 200 samples (each sample was 150 pieces of post larvae with average age 7 days) were taken from 3 active hatcheries and in the second phase, 268 samples from 418 ponds in 5 sites were collected. Samples were tested by "Nested PCR" for detection of WSSV with 1Q2000 commercial kits. Results were negative and with respect to sampling method and sensitivity and specifity of Nested PCR we concluded that cultured shrimps were free of WSSV in 2006 in Bushehr province