336 research outputs found

    A Software Approach to Manage and Maintain Warfighter Training Systems

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    The use of simulation technologies in Warfighter training will need to increase as resource constraints tighten on the US military. Multiple studies have shown that simulation-based training promotes faster skills acquisition and assessment at greatly reduced cost and time. However, as these technologies become more pervasive, in a wider variety of training tasks, integrating them into a cohesive environment is increasingly complex. Industries such as medical and construction use single purpose trainers to teach welding or suturing, but Warfighter training requires multiple systems, with unique capabilities, to interoperate. For example, it may be necessary for a ground-based Soldier trainer to be connected to fighter and tank trainers to adequately prepare for actual missions. The setup, running, debugging, and maintenance of these systems is a very difficult task that can use up resource savings achieved through simulation. As each training system is composed of multiple components (e.g., projectors, computers, and motion trackers), it is imperative to understand items such as: 1) input parameter initialization (e.g., scenario, number of Soldiers, etc.), 2) the real-time status of individual systems, 3) data flow and timing between systems, and 4) software and hardware malfunctions. In this paper, the Mixed Reality Toolbox (MRT), developed to perform these operations, is presented. A review of current research and products available to the training community will be presented. In addition, the issues involved with combining physical, mixed-reality, and virtual reality environments into a single training system will be discussed. Lastly, results will be presented showing the effectiveness of the MRT when used to run two simulated training exercises with systems comprised of five to fifteen different technology and/or real components. In both exercises, the MRT allowed a significant reduction in system setup and runtime compared to comparable setups done previously

    Testosterone and Cardiovascular Disease

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    Abstract Testosterone (T) is the principal male sex hormone. As men age, T levels typically fall. Symptoms of low T include decreased libido, vasomotor instability, and decreased bone mineral density. Other symptoms may include depression, fatigue, erectile dysfunction, and reduced muscle strength/mass. Epidemiology studies show that low levels of T are associated with more atherosclerosis, coronary artery disease, and cardiovascular events. However, treating hypogonadism in the aging male has resulted in discrepant results in regard to its effect on cardiovascular events. Emerging studies suggest that T may have a future role in treating heart failure, angina, and myocardial ischemia. A large, prospective, long-term study of T replacement, with a primary endpoint of a composite of adverse cardiovascular events including myocardial infarction, stroke, and/or cardiovascular death, is needed. The Food and Drug Administration recently put additional restrictions on T replacement therapy labeling and called for additional studies to determine its cardiac safety

    Comparing Training Performance With Vibrotactile Hit Alerts vs. Audio Alerts

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    Live, virtual, and constructive training that integrates dismounted warfighter training with convoy training, pilot training, and other systems has been demonstrated to reduce training time, and studies have shown that a high level of immersion and the illusion of presence in a VR environment contribute to this success. However, current force-on-force training simulators lack one major quality that is needed to impart this strong sense of presence for warfighters: the consequence of getting shot. Simulated return-fire systems have been developed for different purposes including military, police and entertainment. Some use projectiles, but that approach is usually limited to a shoot house configuration rather than outdoors. Other methods use on-body electrodes to provide electric shock or tactors that physically strike the body using solenoids or pneumatics. These systems face challenges of either low body localization (with a small number of tactors) or tethering (if a real-time connection to electricity or air is needed to power the tactors). In this paper, a tactile vest containing commercially available vibrating pagers is evaluated. These pagers allow a focused alert to be given to a Warfighter, indicating the bodily location of the shot and appropriate direction for return fire. They are also cost-effective and easily replaceable. The evaluation included a simple training mission while receiving either vibrotactile feedback vs. auditory spoken alerts of virtual sniper hits and direction of fire. Results showed that a tactile vest made from commercial off-the-shelf pagers performed well as an indicator of fire and could be viable option for integration with future LVC training, especially given its low cost. Also, results suggested that there may be strong individual differences between people in terms of their ability to process vibrotactile vs. auditory feedback while cognitively loaded

    TRAIL-expressing T cells induce apoptosis of vascular smooth muscle cells in the atherosclerotic plaque

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    Acute coronary syndromes (ACS) are precipitated by a rupture of the atherosclerotic plaque, often at the site of T cell and macrophage infiltration. Here, we show that plaque-infiltrating CD4 T cells effectively kill vascular smooth muscle cells (VSMC). VSMCs sensitive to T cell–mediated killing express the death receptor DR5 (TNF-related apoptosis-inducing ligand [TRAIL] receptor 2), and anti-TRAIL and anti-DR5 antibodies block T cell–mediated apoptosis. CD4 T cells that express TRAIL upon stimulation are expanded in patients with ACS and more effectively induce VSMC apoptosis. Adoptive transfer of plaque-derived CD4 T cells into immunodeficient mice that are engrafted with human atherosclerotic plaque results in apoptosis of VSMCs, which was prevented by coadministration of anti-TRAIL antibody. These data identify that the death pathway is triggered by TRAIL-producing CD4 T cells as a direct mechanism of VSMC apoptosis, a process which may lead to plaque destabilization

    Rheumatoid arthritis is an independent risk factor for multi-vessel coronary artery disease: a case control study

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    The risk for cardiovascular (CV) disease is increased in rheumatoid arthritis (RA) but data on the burden of coronary atherosclerosis in patients with RA are lacking. We conducted a retrospective case-control study of Olmsted County (MN, USA) residents with RA and new-onset coronary artery disease (CAD) (n = 75) in comparison with age-and sex-matched controls with newly diagnosed CAD (n = 128). Angiographic scores of the first coronary angiogram and data on CV risk factors and CV events on follow-up were obtained by chart abstraction. Patients with RA were more likely to have multi-vessel coronary involvement at first coronary angiogram compared with controls (P = 0.002). Risk factors for CAD including diabetes, hypertension, hyperlipidemia, and smoking history were not significantly different in the two cohorts. RA remained a significant risk factor for multi-vessel disease after adjustment for age, sex and history of hyperlipidemia. The overall rate of CV events was similar in RA patients and controls; however, there was a trend for increased CV death in patients with RA. In a nested cohort of patients with RA and CAD (n = 27), we measured levels of pro-inflammatory CD4(+)CD28(null )T cells by flow cytometry. These T cells have been previously implicated in the pathogenesis of CAD and RA. Indeed, CD4(+)CD28(null )T cells were significantly higher in patients with CAD and co-existent RA than in controls with stable angina (P = 0.001) and reached levels found in patients with acute coronary syndromes. Patients with RA are at increased risk for multi-vessel CAD, although the risk of CV events was not increased in our study population. Expansion of CD4(+)CD28(null )T cells in these patients may contribute to the progression of atherosclerosis

    Fish Oil for the Reduction of Atrial Fibrillation Recurrence, Inflammation, and Oxidative Stress

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    AbstractBackgroundRecent trials of fish oil for the prevention of atrial fibrillation (AF) recurrence have provided mixed results. Notable uncertainties in the existing evidence base include the roles of high-dose fish oil, inflammation, and oxidative stress in patients with paroxysmal or persistent AF not receiving conventional antiarrhythmic (AA) therapy.ObjectivesThe aim of this study was to evaluate the influence of high-dose fish oil on AF recurrence, inflammation, and oxidative stress parameters.MethodsWe performed a double-blind, randomized, placebo-controlled, parallel-arm study in 337 patients with symptomatic paroxysmal or persistent AF within 6 months of enrollment. Patients were randomized to fish oil (4 g/day) or placebo and followed, on average, for 271 ± 129 days.ResultsThe primary endpoint was time to first symptomatic or asymptomatic AF recurrence lasting >30 s. Secondary endpoints were high-sensitivity C-reactive protein (hs-CRP) and myeloperoxidase (MPO). The primary endpoint occurred in 64.1% of patients in the fish oil arm and 63.2% of patients in the placebo arm (hazard ratio: 1.10; 95% confidence interval: 0.84 to 1.45; p = 0.48). hs-CRP and MPO were within normal limits at baseline and decreased to a similar degree at 6 months (Δhs-CRP, 11% vs. −11%; ΔMPO, −5% vs. −9% for fish oil vs. placebo, respectively; p value for interaction = NS).ConclusionsHigh-dose fish oil does not reduce AF recurrence in patients with a history of AF not receiving conventional AA therapy. Furthermore, fish oil does not reduce inflammation or oxidative stress markers in this population, which may explain its lack of efficacy. (Multi-center Study to Evaluate the Effect of N-3 Fatty Acids [OMEGA-3] on Arrhythmia Recurrence in Atrial Fibrillation [AFFORD]; NCT01235130)

    Serum amyloid A: high-density lipoproteins interaction and cardiovascular risk

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    Aims High-density lipoproteins (HDLs) are considered as anti-atherogenic. Recent experimental findings suggest that their biological properties can be modified in certain clinical conditions by accumulation of serum amyloid A (SAA). The effect of SAA on the association between HDL-cholesterol (HDL-C) and cardiovascular outcome remains unknown. Methods and results We examined the association of SAA and HDL-C with mortality in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study, which included 3310 patients undergoing coronary angiography. To validate our findings, we analysed 1255 participants of the German Diabetes and Dialysis study (4D) and 4027 participants of the Cooperative Health Research in the Region of Augsburg (KORA) S4 study. In LURIC, SAA concentrations predicted all-cause and cardiovascular mortality. In patients with low SAA, higher HDL-C was associated with lower all-cause and cardiovascular mortality. In contrast, in patients with high SAA, higher HDL-C was associated with increased all-cause and cardiovascular mortality, indicating that SAA indeed modifies the beneficial properties of HDL. We complemented these clinical observations by in vitro experiments, in which SAA impaired vascular functions of HDL. We further derived a formula for the simple calculation of the amount of biologically ‘effective' HDL-C based on measured HDL-C and SAA from the LURIC study. In 4D and KORA S4 studies, we found that measured HDL-C was not associated with clinical outcomes, whereas calculated ‘effective' HDL-C significantly predicted better outcome. Conclusion The acute-phase protein SAA modifies the biological effects of HDL-C in several clinical conditions. The concomitant measurement of SAA is a simple, useful, and clinically applicable surrogate for the vascular functionality of HD
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