5,581 research outputs found

    Plasmas generated by ultra-violet light rather than electron impact

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    We analyze, in both plane and cylindrical geometries, a collisionless plasma consisting of an inner region where generation occurs by UV illumination, and an un-illuminated outer region with no generation. Ions generated in the inner region flow outwards through the outer region and into a wall. We solve for this system's steady state, first in the quasi-neutral regime (where the Debye length λD{\lambda}_D vanishes and analytic solutions exist) and then in the general case, which we solve numerically. In the general case a double layer forms where the illuminated and un-illuminated regions meet, and an approximately quasi-neutral plasma connects the double layer to the wall sheath; in plane geometry the ions coast through the quasi-neutral section at slightly more than the Bohm speed csc_s. The system, although simple, therefore has two novel features: a double layer that does not require counter-streaming ions and electrons, and a quasi-neutral plasma where ions travel in straight lines with at least the Bohm speed. We close with a pr\'{e}cis of our asymptotic solutions of this system, and suggest how our theoretical conclusions might be extended and tested in the laboratory.Comment: 10 pages, 3 figures, accepted by Physics of Plasma

    On-line ostracism affects children differently from adolescents and adults

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    This research examines adults', and for the first time, children's and adolescents' reaction to being ostracized and included, using an on-line game, 'Cyberball' with same and opposite sex players. Ostracism strongly threatened four primary needs (esteem, belonging, meaning, and control) and lowered mood among 8- to 9-year-olds, 13- to 14-year-olds, and adults. However, it did so in different ways. Ostracism threatened self-esteem needs more among 8- to 9-year-olds than older participants. Among 13- to 14-year-olds, ostracism threatened belonging more than other needs. Belonging was threatened most when ostracism was participants' first experience in the game. Moreover, when participants had been included beforehand, ostracism threatened meaning needs most strongly. Gender of other players had no effect. Practical and developmental implications for social inclusion and on-line experiences among children and young people are discussed

    Preventing Falls with Vitamin D

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    Falls are the number one cause for injury-related morbidity and mortality in West Virginia’s seniors. Multiple independent variables contribute to the risk of a fall: previous falls, alterations in balance and vision, impairments in gait and strength, and medications most highly correlate with the risk for a fall. Vitamin D supplementation is emerging as an easy, safe and well-tolerated fall reduction/prevention strategy due to the beneficial effects on the musculoskeletal system with improvements in strength, function and navigational abilities. From meta-analysis data, maximal fall reduction benefit in seniors is achieved when correcting vitamin D deficiency and when using adjunctive calcium supplementation. It is therefore recommended that practitioners in our state screen for fall risks and consider the addition of supplementation protocols that provide sufficient vitamin D and calcium to our seniors

    Physical Education in West Virginia Schools: Are We Doing Enough to Generate Peak Bone Mass and Promote Skeletal Health?

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    Peak bone mass (PBM) is attained at 25-35 years of age, followed by a lifelong decline in bone strength. The most rapid increase in bone mass occurs between the ages of 12-17. Daily school physical education (PE) programs have been shown to produce measurable increases in PBM, but are not federally mandated. Increases in PBM can decrease the lifelong risk of osteoporosis and fractures; critical for West Virginia prevention programs. Nationally only 1 in 6 schools require PE three days per week, with 4% of elementary schools, 8% of middle schools and 2% of high schools providing daily PE. In 2005, West Virginia passed the Healthy Lifestyles Act that returned physical education to the K-12 curriculum. This law requires only one credit of PE from grades 9-12 and provides only 35% of the recommended PE for grades K-12. This article highlights the relationship of PE to PBM and discusses the potential impact on West Virginia skeletal health

    Improvement in mental health following total hip arthroplasty: the role of pain and function

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    BACKGROUND: Mental health has been shown to improve after total hip arthroplasty (THA). Little is known about the role of pain and function in this context. We assessed whether change in mental health was associated with improvement in pain and function 1 year post-surgery. METHODS: This prospective study included patients enrolled in a THA registry from 2010 to 2014. We examined the mental component score (MCS) before and 1 year post-surgery, and 1-year change, in association with Western Ontario McMaster Universities (WOMAC) pain and function scores. All scores were normalized, ranging from 0 to 100 (larger score indicating better outcome). Analyses were adjusted for potential confounders. RESULTS: Our study included 610 participants, of which 53% were women. Descriptive statistics are as follows: the average (SD) for age (years) was 68.5 (11.8), and for BMI was 26.9 (4.9). In addition, the MCS average (SD) at baseline was 44.7 (11.2), and at 1-year after THA was 47.5 (10.5). The average change from baseline to 1-year post-THA in MCS was 2.8 (95% CI: 1.9, 3.6), for an effect size of 0.26. As for the WOMAC pain score, the average change from baseline to 1-year post-THA was 44.2 (95%CI: 42.4, 46.0), for an effect size of 2.5. The equivalent change in WOMAC function was 38.1 (95% CI: 36.2, 40.0), for an effect size of 2.0. Results from multivariable analysis controlling for covariates showed that an improvement of 10 points in the 1-year change in pain score resulted in a 0.78 point (95%: CI 0.40, 1.26) increase in the 1-year change in MCS, whereas a 10-point improvement in the 1-year change in function was associated with a 0.94 point (95% CI: 0.56, 1.32) increase. CONCLUSIONS: Mental health significantly improved from baseline to 1-year post-THA. Greater improvement in pain and function was associated with greater improvement in mental health 1 year post-THA

    Total hip arthroplasty and mental health status

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    Purpose. Total hip arthroplasty (THA) effectively restores function and alleviates pain in patients with end-stage hip osteoarthritis. Pain affects mood through its effect on disability and fatigue. Few studies have examined mental health as a consequence of pain or function after THA. We assessed change in mental health 1-year post-surgery, and examined whether change in pain and function predict change in mental health. Methods. We used data from a prospective THA registry that began in 1996 at a large public Geneva University hospital. We included surgeries performed 2010 and 2012-2014, with demographic information, body mass index (BMI), co-morbidities, baseline and 1-year post-surgery WOMAC pain and function scores, and the SF-12 mental health component score (MCS). The pain, function, and MCS scores were normalized and ranged from 0-100; increasing score indicating better outcome. We calculated descriptive statistics, and used multivariable linear regression to predict 1-year change in MCS. Results. Of 610 participants, mean (SD) age was 68.5 (11.8) years and BMI of 26.9 (4.9), 53% were women. Mean MCS was 44.7 (11.2) at baseline and 47.5 (10.5) at 1-year post surgery; average 1-year change was 2.8 (95% CI 1.9-3.6). WOMAC pain score was 39.6 (18.3) at baseline and 83.8 (20.4) at 1-year post surgery; 1-year change was 44.2 (95% CI 42.4-46.0). Corresponding WOMAC function was 40.2 (18.8) and 78.3 (22.1); 1-year change was 38.1 (95% CIs 36.2-40.0). On average, a 10-point increase in 1-year change in pain score was associated with a 0.7 point increase in the adjusted 1-year change in MCS (95% CI 0.2-1.1). The change in function was associated with a 0.9 point increase in 1-year change in MCS (95% CI 0.5-1.4). Conclusion. Mental health significantly improved from baseline to 1-year post-surgery. Patients whose pain and function scores improved the most had also the greatest improvement in mental health

    The natural history of regional wall motion in the acutely infarcted canine ventricle

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    Two-dimensional echocardiography was employed to define the natural history of regional wall motion abnormalities in a canine model of acute experimental myocardial infarction. Serial short-axis two-dimensional echocardiograms were recorded in 11 closed chest dogs before coronary occlusion and 10, 30, 60, 180 and 360 minutes after permanent coronary ligation. Radiolabeled microsphere-derived blood flows were obtained in each study period and the histochemical (triphenyltetrazolium chloride) extent of infarction was determined at 6 hours. Previously published methods were used to quantitate field by field (every 16.7 ms) excursion of 36 evenly spaced endocardial targets. The circumferential extent of abnormal wall motion was followed sequentially using previously published definitions of abnormality: 1) systolic fractional radial change of less than 20%; 2) dyskinesia (systolic bulging) at the point in time (echocardiographic field) in which there is maximal dyskinesia; and 3) correlation with composite normal ray motion falling outside the 95 % confidence limits defined in the control period. On the basis of the triphenyltet razolium chloride staining pattern, the ventricle was divided into five zones: central infarct zone, zone with greater than 25% transmural infarction, total infarct zone, border zones and normal zone. Mean systolic fractional radial change was calculated for each zone and used as an index of the magnitude of abnormal wall motion.Regardless of the definition of abnormality employed, the circumferential extent of abnormal wall motion manifested at 10 minutes after occlusion did not significantly change, even up to 6 hours later. Similarly, 10 minutes after coronary occlusion the three infarct zones and border zones demonstrated significantly reduced systolic fractional radial change. This remained stable over the remainder of the 6 hour study period.It is concluded that once established at 10 minutes after coronary occlusion, the circumferential extent and magnitude of abnormal wall motion do not significantly change in the immediate postinfarct (6 hour) period

    Vitamin K2 (menaquinone) Supplementation and its Benefits in Cardiovascular Disease, Osteoporosis, and Cancer

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    Vitamin K is known to play an essential role in the coagulation cascade; however, a growing body of research has found that a subtype of this vitamin, vitamin K2 (menaquinone) may have a beneficial effect in osteoporosis, cardiovascular disease, and cancer. This purpose of this article is to provide a comprehensive review of recent literature regarding menaquinone and its role in human health. This review discusses the physiology of menaquinone, its clinical benefits in cardiovascular disease, osteoporosis, and cancer, and how it may interact with certain medications. The authors conclude that menaquinone supplementation has been shown to improve carboxylation of osteocalcin and matrix-Gla protein to their active forms, two proteins that possess important roles in calcium distribution. In the setting of cardiovascular disease, menaquinone intake has been shown to lower the risk of coronary calcification and coronary heart disease, and a randomized controlled trial has demonstrated that it can reduce arterial stiffness. In osteoporosis, menaquinone has been shown by numerous randomized controlled trials to decrease the rate of bone loss at the lumbar spine and forearm and reduce the risk of fracture. In cancer, menaquinone intake has been shown to reduce overall incidence and mortality; clinical trials have suggested that it may have a role in reducing recurrence and death from hepatocellular carcinoma. However, in all clinical settings, more large randomized controlled trials are needed to definitively determine the clinical benefits of menaquinone supplementation, as many studies have failed to show any significant benefit. Lastly, more research is needed to determine how menaquinone supplementation interacts with medications such as warfarin, bile-acid sequestrants, orlistat, mineral oil and CYP3A4 substrates

    Concentrations of heavy metal in different parts of the gastropod, Faunus ater (linnaeus), collected from intertidal areas of Peninsular Malaysia.

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    Marine gastropods, Faunus ater (Linnaeus), were collected from Pantai Sri Tujoh (Kelantan), Pantai Bisikan Bayu (Kelantan), Kg. Telaga Nenas (Perak) and Kesang Laut (Johor). Soft tissues of gastropods were dissected into digestive caecum (DC), foot, remainder, muscle, and operculum. The shell and dissected parts were analyzed for Cd, Cu, Ni, and Pb. It was found that the DC and the remainder accumulated high concentrations of Cu ranging between 159.1 and 290.2 μg/g dw. The shell was shown to highly accumulate non-essential Pb, Ni, and Cd compared to the soft tissues. Meanwhile, higher bioavailabilities of Cd and Cu were found in Pantai Sri Tujoh, whereas higher bioavailabilities of Ni and Pb were found in Pantai Bisikan Bayu compared to other sampling sites. The present results suggested that F. ater could be used as a potential biomonitor of heavy metal contamination. However, further studies are still needed in order to validate the use of F. ater as a good biomonitor of heavy metal pollution
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