Incidence and risk factors of severe traumatic brain injury resulting from road accidents: a population-based study

A population-based study was carried out in 1996-2001 to provide the incidence and to identify the risk factors of severe traumatic brain injury (TBI) resulting from a road accident. The severe TBI was defined as an injury to the brain or the skull, excluding scalp injuries, with an abbreviated injury scale (AIS) severity score greater than 2. The severe TBI of 1238 patients were described. The annual incidence and mortality of severe TBI were, respectively, 13.7 per 100,000 and 5.3 per 100,000. The fatality rate increased from 20% in childhood to 71% over 75-year-old. Compared to restrained car occupants, the odds ratio for having a severe TBI was 18.1 (95% confidence interval, CI=12.8-25.5) for un-helmeted motorcyclists, 9.2 (95% CI=7.5-11.3) for pedestrians, 6.4 (95% CI=4.7-8.8) for un-helmeted cyclists, 3.9 (95% CI=3.1-4.8) for unrestrained car occupants and 2.8 (95% CI=2.2-3.5) for helmeted motorcyclists. Even after adjustment for several severity factors, male gender and age above 55 were both risk factors. Prevention programs aiming at improving the head protection should be promoted. The circumstances of the accident should be taken into account to predict a severe TBI.     

Investigation of the relationship between facial injuries and traumatic brain injuries using a realistic subject-specific finite element head model

In spite of anatomic proximity of the facial skeleton and cranium, there is lack of information in the literature regarding the relationship between facial and brain injuries. This study aims to correlate brain injuries with facial injuries using finite element method (FEM). Nine common impact scenarios of facial injuries are simulated with their individual stress wave propagation paths in the facial skeleton and the intracranial brain. Fractures of cranio-facial bones and intracranial injuries are evaluated based on the tolerance limits of the biomechanical parameters. General trend of maximum intracranial biomechanical parameters found in nasal bone and zygomaticomaxillary impacts indicates that severity of brain injury is highly associated with the proximity of location of impact to the brain. It is hypothesized that the midface is capable of absorbing considerable energy and protecting the brain from impact. The nasal cartilages dissipate the impact energy in the form of large scale deformation and fracture, with the vomer–ethmoid diverging stress to the “crumpling zone” of air-filled sphenoid and ethmoidal sinuses; in its most natural manner, the face protects the brain. This numerical study hopes to provide surgeons some insight in what possible brain injuries to be expected in various scenarios of facial trauma and to help in better diagnosis of unsuspected brain injury, thereby resulting in decreasing the morbidity and mortality associated with facial trauma.     

Fitness-to-drive after mild traumatic brain injury: Mapping the time trajectory of recovery in the acute stages post injury

Introduction

Little is known about the trajectory of recovery in fitness-to-drive after mild traumatic brain injury (mTBI). This means that health-care professionals have limited evidence on which to base recommendations to this cohort about driving.

Objective

To determine fitness-to-drive status of patients with a mTBI at 24 h and two weeks post injury, and to summarise issues reported by this cohort about return to driving.

Method

Quasi-experimental case-control design. Two groups of participants were recruited: patients with a mTBI (n = 60) and a control group with orthopaedic injuries (n = 60). Both groups were assessed at 24 h post injury on assessments of fitness-to-drive. Follow-up occurred at two weeks post injury to establish driver status.

Main Measures

Mini mental state examination, occupational therapy-drive home maze test (OT–DHMT), Road Law Road Craft Test, University of Queensland-Hazard Perception Test, and demographic/interview form collected at 24 h and at two weeks.

Results

At the 24 h assessment, only the OT–DHMT showed a difference in scores between the two groups, with mTBI participants being significantly slower to complete the test (p = 0.01). At the two week follow-up, only 26 of the 60 mTBI participants had returned to driving. Injury severity combined with scores from the 24 h assessment predicted 31% of the variance in time taken to return to driving. Delayed return to driving was reported due to: “not feeling 100% right” (n = 14, 23%), headaches and pain (n = 12, 20%), and dizziness (n = 5, 8%).

Conclusion

This research supports existing guidelines which suggest that patients with a mTBI should not to drive for 24 h; however, further research is required to map factors which facilitate timely return to driving.     

The effect of changes in condom usage and antiretroviral treatment coverage on human immunodeficiency virus incidence in South Africa: a model-based analysis

This study aims to assess trends in human immunodeficiency virus (HIV) incidence in South Africa, and to assess the extent to which prevention and treatment programmes have reduced HIV incidence. Two models of the South African HIV epidemic, the STI (sexually transmitted infection)–HIV Interaction model and the ASSA2003 AIDS and Demographic model, were adapted. Both models were fitted to age-specific HIV prevalence data from antenatal clinic surveys and household surveys, using a Bayesian approach. Both models suggest that HIV incidence in 15–49 year olds declined significantly between the start of 2000 and the start of 2008: by 27 per cent (95% CI: 21–32%) in the STI–HIV model and by 31 per cent (95% CI: 23–39%) in the ASSA2003 model, when expressed as a percentage of incidence rates in 2000. By 2008, the percentage reduction in incidence owing to increased condom use was 37 per cent (95% CI: 34–41%) in the STI–HIV model and 23 per cent (95% CI: 14–34%) in the ASSA2003 model. Both models also estimated a small reduction in incidence owing to antiretroviral treatment by 2008. Increased condom use therefore appears to be the most significant factor explaining the recent South African HIV incidence decline.     

International variation in clinical injury incidence: exploring the performance of indicators based on health care, anatomical and outcome criteria

OBJECTIVE: To analyse international variation in clinical injury incidence, and explore the performance of different injury indicators in cross-country comparisons. METHODS: Hospital discharge data of seven European countries (Austria, Denmark, Ireland, Netherlands, Norway, England and Wales) were analysed. We tested existing and newly developed indicators based on (a) health care use, (b) anatomical criteria, or (c) expected health outcome: admissions excluding day-cases (a), hospital stay 4+ (a) and 7+ days (a), (serious) long-bone fractures (b), selected radiological verifiable fractures 'SRVFs' (b), and indicators based on international (Global Burden of Disease) and Dutch disability weights). Assessment criteria were reduction in incidence variation and length of stay in hospital, and the association between incidence and mortality rates. RESULTS: Indicators based on health care use led to increased variation in incidence rates. Long bone fractures and SRVFs, and both indicators based on injuries with moderate to high disability showed similar variation in clinical incidence compared to the crude rates, smaller variation in median length of stay in hospital and a good association with mortality rates. CONCLUSION: No perfect or near perfect indicators of clinical injury incidence exist. For international comparisons, indicators based on disability weights, SRVFs and long bone fractures may be sensible indicators to use, in the absence of a direct measure of anatomical severity.     

Transdermal delivery of alprazolam from a monolithic patch: formulation based on in vitro characterization

Alprazolam, a benzodiazepine widely used for the treatment of psychiatric disorders, has been aimed to be formulated in a transdermal delivery system (TDS) prototype. A series of TDS prototypes dosed in all cases at 0.35 mg·cm^?2 of alprazolam were prepared as a monolithic drug in adhesive matrix using acrylic pressure-sensitive adhesives (PSA) of acrylate vinyl acetate (Duro-tack^®). The effects of several permeation enhancers as azone, transcutol, propylene glycol, dodecyl alcohol, decyl alcohol, diethanolamine, N-methyl pyrrolidone and lauric acid were studied. Prototypes have been characterized based on adhesion parameters (peel adhesion and shear adhesion), in vitro human skin permeation and in vitro drug release according to European Pharmacopoeia for the selected prototype. Best results show that a combination of permeation enhancers from different chemical groups is able to provide almost a 33 fold increase in the transdermal alprazolam flux of an aqueous saturated dispersion (from 0.054?±?0.019 to 1.76?±?0.21 μg h.cm^?2). Based on these in vitro flux data, a predictive simulation of the achievable plasmatic levels was performed assuming a constant systemic infusion of drug. In summary, it is possible to obtain a prototype of a TDS of alprazolam with adequate adhesive properties (peel adhesion and shear adhesion) and able to predict sustained therapeutic plasmatic levels.     

Effects on accidents of changes in the use of studded tyres in major cities in Norway: A long-term investigation

This paper reports the findings of two studies made eleven years apart in Norway (0035 and 0025) to evaluate effects on accidents of changes in the use of studded tyres in major cities in Norway. The first study covered the period from 1991 to 2000, the second study covered the period from 2002 to 2009. In both these periods, large changes in the percentage of cars using studded tyres were found in the cities that were included in the study. There was, in most cities, a tendency for the use of studded tyres to go down. Effects of these changes on injury accidents were evaluated by means of negative binomial regression models, using city and day as the unit of analysis, and including more than twenty explanatory variables in order to control for confounding factors. The effects of changes in the percentage of cars using studded tyres were well described by an accident modification function (dose–response curve), relating the size of changes in the number of accident to the size of the change in the use of studded tyres. Accidents during the season when the use of studded tyres is permitted were found to increase by about 5 percent if the use of studded tyres was reduced by 25 percentage points (e.g. from 50 to 25 percent) and to decline by about 2 percent when the use of studded tyres increased by 20 percentage points.     

Modelling the initial phase of an epidemic using incidence and infection network data: 2009 H1N1 pandemic in Israel as a case study

This paper presents new computational and modelling tools for studying the dynamics of an epidemic in its initial stages that use both available incidence time series and data describing the population''s infection network structure. The work is motivated by data collected at the beginning of the H1N1 pandemic outbreak in Israel in the summer of 2009. We formulated a new discrete-time stochastic epidemic SIR (susceptible-infected-recovered) model that explicitly takes into account the disease''s specific generation-time distribution and the intrinsic demographic stochasticity inherent to the infection process. Moreover, in contrast with many other modelling approaches, the model allows direct analytical derivation of estimates for the effective reproductive number (R_e) and of their credible intervals, by maximum likelihood and Bayesian methods. The basic model can be extended to include age–class structure, and a maximum likelihood methodology allows us to estimate the model''s next-generation matrix by combining two types of data: (i) the incidence series of each age group, and (ii) infection network data that provide partial information of ‘who-infected-who’. Unlike other approaches for estimating the next-generation matrix, the method developed here does not require making a priori assumptions about the structure of the next-generation matrix. We show, using a simulation study, that even a relatively small amount of information about the infection network greatly improves the accuracy of estimation of the next-generation matrix. The method is applied in practice to estimate the next-generation matrix from the Israeli H1N1 pandemic data. The tools developed here should be of practical importance for future investigations of epidemics during their initial stages. However, they require the availability of data which represent a random sample of the real epidemic process. We discuss the conditions under which reporting rates may or may not influence our estimated quantities and the effects of bias.     

Effects of excessive speeding and falling asleep while driving on crash injury severity in Ethiopia: A generalized ordered logit model analysis

The severity of injury from vehicle crash is a result of a complex interaction of factors related to drivers’ behavior, vehicle characteristics, road geometric and environmental conditions. Knowing to what extent each factor contributes to the severity of an injury is very important. The objective of the study was to assess factors that contribute to crash injury severity in Ethiopia. Data was collected from June 2012 to July 2013 on one of the main and busiest highway of Ethiopia, which extends from the capital Addis Ababa to Hawassa. During the study period a total of 819 road crashes was recorded and investigated by trained crash detectors. A generalized ordered logit/partial proportional odds model was used to examine factors that might influence the severity of crash injury. Model estimation result suggested that, alcohol use (Coef. = 0.5565; p-value = 0.017), falling asleep while driving (Coef. = 1.3102; p-value = 0.000), driving at night time in the absence of street light (Coef. = 0.3920; p-value = 0.033), rainfall (Coef. = 0.9164; p-value = 0.000) and being a minibus or vans (Coef. = 0.5065; p-value = 0.013) were found to be increased crash injury severity. On the other hand, speeding was identified to have varying coefficients for different injury levels, its highest effects on sever and fatal crashes. In this study risky driving behaviors (speeding, alcohol use and sleep/fatigue) were a powerful predictor of crash injury severity. Therefore, better driver licensing and road safety awareness campaign complimented with strict police enforcement can play a pivotal role to improve road safety. Further effort needed as well to monitor speed control strategies like; using the radar control and physical speed restraint measures (i.e., rumble strips).     

Effects of synthetic oil in a compression refrigeration system using R410A. Part II: quality of heat transfer and pressure losses within the heat exchangers

The consequences of the oil rejected by the compressor of a vapour-compression refrigeration system on the operation of the evaporator and condenser are analysed. The modelled prototype uses the mixture of HFC R410A and a synthetic polyolester (POE) oil. The rise of the amount of lubricant circulating in the system leads to a progressive change in the behaviour of the mixture of refrigerant and oil that, for the higher oil mass fraction, evolves like a zeotropic mixture. One also observes that the presence of lubricant is generally associated with a fall of the performances of the heat exchangers, except however in the evaporator where an optimum is observed when the quantity of oil is equal to 0.1% of the total mass of the mixture. Some conclusions are drawn about the choice of correlations for the calculation of the refrigerant side heat transfer coefficient in a plate evaporator.     

Localization and characterization of latch-up sensitive areas using a laser beam: Influence on design rules of ICs in CMOS technology

The technique of ‘scanning’ with a laser beam permits a localization of latch-up sites in CMOS technology with a resolution less than one micron. Electrical simulations correlated to experimental curves of ‘supply current’ versus ‘photo-induced current’ offer a good evaluation of the predominant parameters of the parasitic structure.     

Effects of synthetic oil in a compression refrigeration system using R410A. Part I: modelling of the whole system and analysis of its response to an increase in the amount of circulating oil

Results concerning a model of vapour compression refrigeration system using R410A, a binary HFC blend, and designed to take into account the effects of the oil rejected by the compressor, are presented. These effects are negligible when the lubricant does not exceed 0.5% of the total refrigerant weight; above this value, the performances of the system decrease significantly.     

Two-phase lattice Boltzmann simulation of natural convection in a Cu-water nanofluid-filled porous cavity: Effects of thermal boundary conditions on heat transfer and entropy generation

The present work investigates the effect of four different thermal boundary conditions on natural convection in a fluid-saturated square porous cavity to make a judicious choice of optimal boundary condition on the basis of entropy generation, heat transfer and degree of temperature uniformity. Four different heating conditions- uniform, sinusoidal and two different linear temperature distributions are applied on the left vertical wall of the cavity respectively, while maintaining the right vertical wall uniformly cooled and the horizontal walls thermally insulated. The two-phase thermal lattice Boltzmann (TLBM) model for nanofluid is extended to simulate nanofluid flow through a porous medium by incorporating the Brinkman–Forchheimer-extended Darcy model. The close agreement between present LBM solutions with the existing published results lends validity to the present findings. The current results indicate that the uniform and bottom to top linear heating are found to be efficient heating strategies depending on Rayleigh number (10³?≤?Ra?≤?10⁵) and Darcy number (10^?1?≤?Da?≤?10^?6). It is observed that the nanofluid improves the energy efficiency by reducing the total entropy generation and enhancing the heat transfer rate although its augmentation depends on the optimal volume fraction of nanoparticles.     

Optical constants of silicone-like (Si:Ox:Cy:Hz) thin films deposited on quartz using hexamethyldisiloxane in a remote RF hollow cathode discharge plasma

Deposition of amorphous silicone-like (Si:O_x:C_y:H_z) thin films in a remote RF hollow cathode discharge plasma using hexamethyldisoloxane as monomer and Ar as feed gas has been investigated for films optical constants and plasma diagnostic as a function of RF power (100-300 W) and precursor flow rate (1-10 sccm). Plasma diagnostic has been performed using Optical Emission Spectroscopy (OES). The optical constants (refractive index, extinction coefficient and dielectric constant) have been obtained by reflection/transmission measurements in the range 300-700 nm. It is found that the refractive index increases from 1.92 to 1.97 with increasing power from 100 to 300 W, and from 1.70 to 1.92 with increasing precursor flow rate from 1 to 10 sccm. The optical energy band gap E_g and the optical-absorption tail ΔE have been estimated from optical absorption spectra, it is found that E_g decreases from 3.28 to 3.14 eV with power increase from 100 to 300 W, and from 3.54 to 3.28 eV with precursor flow rate increase from 1 to 10 sccm. ΔE is found to increase with applied RF power and precursor flow rate increase. The dependence of optical constants on deposition parameters has been correlated to plasma OES.