449 research outputs found

    Effect of the foam embellishments on the pedestrian safety of the vehicle front protection systems

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    Pedestrian safety related compliance requirements are very important in case of design and development of the vehicle front protection systems. Computer aided engineering impact simulations were carried out to evaluate Head Injury Criterion (HIC) of a typical bullbar impacting it with an adult headform and correlated with experimental results. Impact simulations were carried out on the same bullbar covered with semiā€rigid polyurethane foam to study the effect of foam embellishments on the pedestrian safety. Results obtained from the impact simulations were presented in this paper

    Application of bifurcation methods for the prediction of low-speed aircraft ground performance

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    The design of aircraft for ground maneuvers is an essential part in satisfying the demanding requirements of the aircraft operators. Extensive analysis is done to ensure that a new civil aircraft type will adhere to these requirements, for which the nonlinear nature of the problem generally adds to the complexity of such calculations. Small perturbations in velocity, steering angle, or brake application may lead to significant differences in the final turn widths that can be achieved. Here, the U-turn maneuver is analyzed in detail, with a comparison between the two ways in which this maneuver is conducted. A comparison is also made between existing turn-width prediction methods that consist mainly of geometric methods and simulations and a proposed new method that uses dynamical systems theory. Some assumptions are made with regard to the transient behavior, for which it is shown that these assumptions are conservative when an upper bound is chosen for the transient distance. Furthermore, we demonstrate that the results from the dynamical systems analysis are sufficiently close to the results from simulations to be used as a valuable design tool. Overall, dynamical systems methods provide an order-of-magnitude increase in analysis speed and capability for the prediction of turn widths on the ground when compared with simulations. Nomenclature co = oleo damping coefficient, N s2 =m2 cz = tire vertical damping coefficient Fco = damping force in oleo due to the orifice,

    Independent and Interactive Influences of Environmental UVR, Vitamin D Levels, and Folate Variant MTHFD1-rs2236225 on Homocysteine Levels

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    Elevated homocysteine (Hcy) levels are a risk factor for vascular diseases. Recently, increases in ultraviolet radiation (UVR) have been linked to decreased Hcy levels. This relationship may be mediated by the status of UVR-responsive vitamins, vitamin D and folate, and/or genetic variants influencing their levels; however, this has yet to be examined. Therefore, the independent and interactive influences of environmental UVR, vitamin D and folate levels and related genetic variants on Hcy levels were examined in an elderly Australian cohort (n = 619). Red blood cell folate, 25-hydroxyvitamin D (25(OH)D), and plasma Hcy levels were determined, and genotyping for 21 folate and vitamin D-related variants was performed. Erythemal dose rate accumulated over six-weeks (6W-EDR) and four-months (4M-EDR) prior to clinics were calculated as a measure of environmental UVR. Multivariate analyses found interactions between 6W-EDR and 25(OH)D levels (pinteraction = 0.002), and 4M-EDR and MTHFD1-rs2236225 (pinteraction = 0.006) in predicting Hcy levels. The association between 6W-EDR and Hcy levels was found only in subjects within lower 25(OH)D quartiles (<33.26 ng/mL), with the association between 4M-EDR and Hcy occurring only in subjects carrying the MTHFD1-rs2236225 variant. 4M-EDR, 6W-EDR, and MTHFD1-rs2236225 were also independent predictors of Hcy. Findings highlight nutrientā€“environment and geneā€“environment interactions that could influence the risk of Hcy-related outcomes

    Association of plasma neurofilament light chain with glycaemic control and insulin resistance in middle-aged adults

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    Aims: This study aimed to determine the association of plasma neurofilament light (NfL), a marker of neurodegeneration, with diabetes status and glycaemic parameters in people with normal glycaemia (NG), pre-diabetes (PD) and type 2 diabetes (T2D). Methods: Clinical and descriptive data for the diagnostic groups, NG (n=30), PD (n=48) and T2D (n=29), aged between 40 and 75 years were included in this cross-sectional analysis. Plasma NfL levels were analyzed using the ultra-sensitive single-molecule array (Simoa) platform. Results: A positive correlation was evident between plasma NfL and fasting glucose (r = 0.2824; p = 0.0032). Plasma NfL levels were not correlated with fasting insulin and insulin resistance. Plasma Nfl levels were significantly different across the diabetes groups (T2D \u3e PD \u3e NG, p = 0.0046). Post-hoc analysis indicated significantly higher plasma NfL levels in the T2D [12.4 (5.21) pg/mL] group than in the PD [10.2 (4.13) pg/mL] and NG [8.37 (5.65) pg/mL] groups. The relationship between diabetes status and NfL remained significant after adjusting for age, sex, BMI, HOMA-IR and physical activity (adjusted r2 = 0.271, p = 0.035). Conclusions: These results show biomarker evidence of neurodegeneration in adults at risk or with T2D. Larger sample size and longitudinal analysis are required to better understand the application of NfL in people with risk and overt T2D

    A systematic review of the relative efficacy and toxicity of treatment regimens for HIV-associated cerebral toxoplasmosis: is trimephoprim-sulfamethaxozole a real option?

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    Background: Pyrimethamine and sulfadiazine (P-S) combination is effective and considered the mainstay therapy for cerebral toxoplasmosis (CT). Alternative treatment regimens are available, but their relative efficacy and tolerability are not well known. Particularly, trimephoprim-sulfamethaxozole (TMP-SMX) shows potential advantages (i.e., tolerability, posology, parenteral formulation, cost, and accessibility) but its use is infrequent when P-S is available. Methods: We searched PubMed and 4 other databases to identify randomized controlled trials (RCTs) and cohort studies comparing different regimens for the treatment of HIV-associated CT. Two independent reviewers searched and identified studies and extracted data. Risk ratios (RRs) were pooled across studies using random-effects models. Results: Nine studies were included (5 RCTs, 3 retrospective cohorts, 1 prospective cohort). Treatment with P-S has the same or better clinical efficacy than P-C or TMP-SMX in terms of partial or complete response clinical response (P-C vs P-S: RR 0.87, 95%CI 0.70-1.08; TMP-SMX vs P-S: RR 0.97, 95%CI 0.78-1.21) and radiological response (P-C vs P-S: RR 0.92, 95%CI 0.82-1.03). Safety profile in terms of skin rash (P-C vs P-S: RR 0.81, 95%CI 0.56-1.17; TMP-SMX vs P-S: RR 0.17, 95%CI 0.02-1.29), liver impairment (P-C vs P-S: RR 0.48, 95%CI 0.24-0.97) and drug discontinuation due to adverse events (P-C vs P-S: RR 0.32, 95%CI 0.07-1.47) were worse with P-S regimen. Conclusion: The available evidence fails to identify any one superior regimen for the treatment of CT. However, P-S regimen has worse safety profile than P-C or TMP-SMX. Although current evidence does not allow a definitive recommendation, use of TMP-SMX for treatment of HIV-associated CT is consistent with the available data. More large studies comparing alternative therapies are needed.IDWeek, Evento que se llevĆ³ a cabo del 7 -11 de Octubre de 2015, en la ciudad de San Diego, CA, EE.UU. Evento SesiĆ³n HIV: Other Opportunistic Infections in HIV. Saturday, October 10, 2015. Room: Poster Hal

    Dynamical systems methods for evaluating aircraft ground manoeuvres

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    Normalization of a conversation tool to promote shared decision making about anticoagulation in patients with atrial fibrillation within a practical randomized trial of its effectiveness: a cross-sectional study.

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    BACKGROUND: Shared decision making (SDM) implementation remains challenging. The factors that promote or hinder implementation of SDM tools for use during the consultation, including contextual factors such as clinician burnout and organizational support, remain unclear. We explored these factors in the context of a practical multicenter randomized trial evaluating the effectiveness of an SDM conversation tool for patients with atrial fibrillation considering anticoagulation therapy. METHODS: In this cross-sectional study, we recruited clinicians who were regularly involved in conversations with patients regarding anticoagulation for atrial fibrillation. Clinicians reported their characteristics and burnout symptoms using the two-item Maslach Burnout Inventory. Clinicians were trained in using the SDM tool, and they recorded their perceptions of the tool's normalization potential using the Normalization MeAsure Development (NoMAD) survey instrument and verbally reflected on their answers to these survey questions. When possible, the training sessions and clinicians' verbal responses to the conversation tool were recorded. RESULTS: Our study comprised 183 clinicians recruited into the trial (168 with survey responses and 112 with recordings). Overall, clinicians gave high scores to the normalization potential of the intervention; they endorsed all domains of normalization to the same extent, regardless of site, clinician characteristics, or burnout ratings. In interviews, clinicians paid significant attention to making sense of the tool. Tool buy-in seemed to depend heavily on their ability to see the tool as accurate and "evidence-based" and their perceptions of having time in the consultation to use it. CONCLUSIONS: While time in the consultation remains a barrier, we did not find a significant association between burnout symptoms and normalization of an SDM conversation tool. Possible areas for improving the normalization of SDM conversation tools in clinical practice include enabling collaboration among clinicians to implement the tool and reporting how clinicians elsewhere use the tool. Direct measures of normalization (i.e., observing how often clinicians access the tool in practice outside of the clinical trial) may further elucidate the role that contextual factors, such as clinician burnout, play in the implementation of SDM. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02905032. Registered on 9 September 2016
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