4,605 research outputs found

    Cellular excitability and the regulation of functional neuronal identity: from gene expression to neuromodulation

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    The intrinsic properties of a neuron determine the translation of synaptic input to axonal output. It is this input– output relationship that is the heart of all nervous system activity. As such, the overall regulation of the intrinsic excitability of a neuron directly determines the output of that neuron at a given point in time, giving the cell a unique “functional identity.” To maintain this distinct functional output, neurons must adapt to changing patterns of synaptic excitation. These adaptations are essential to prevent neurons from either falling silent as synaptic excitation falls or becoming saturated as excitation increases. In the absence of stabilizing mechanisms, activity-dependent plasticity could drive neural activity to saturation or quiescence. Furthermore, as cells adapt to changing patterns of synaptic input, presumably the overall balance of intrinsic conductances of the cell must be maintained so that reliable output is achieved (Daoudal and Debanne, 2003; Turrigiano and Nelson, 2004; Frick and Johnston, 2005). Although these regulatory phenomena have been well documented, the molecular and physiological mechanisms involved are poorly understood

    Bubble-Mediated Gas Transfer and Gas Transfer Suppression of DMS and CO2

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    Direct dimethyl sulfide (DMS) flux measurements using eddy covariance have shown a suppression of gas transfer at medium to high wind speed. However, not all eddy covariance measurements show evidence of this suppression. Processes, such as wave-wind interaction and surfactants, have been postulated to cause this suppression. We measured DMS and carbon dioxide eddy covariance fluxes during the Asian summer monsoon in the western tropical Indian Ocean (July and August 2014). Both fluxes and their respective gas transfer velocities show signs of a gas transfer suppression above 10 m/s. Using a wind-wave interaction, we describe a flow separation process that could be responsible for a suppression of gas transfer. As a result we provide a Reynolds number-based parameterization, which states the likelihood of a gas transfer suppression for this cruise and previously published gas transfer data. Additionally, we compute the difference in the gas transfer velocities of DMS and CO2 to estimate the bubble-mediated gas transfer using a hybrid model with three whitecap parameterizations

    The Risk Factors Associated with Malaria Incidence in the Elelim Public Health Center in Yalimo District, Papua Province

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    Background: Malaria is still an endemic disease and one of Papua's health problems. Indonesia is the seventh largest in the world with 200,378 cases. In the province of Papua, the district of Yalimo is the third-highest with 18,821 cases. The Government is working to detect and prevent malaria in Papua Province by launching a program called "Malaria Elimination in Papua Province by 2030." Research Objectives: Identify the risk factors associated with malaria incidence at the Elelim Public Health Center in Yalimo District, Papua Province. Research method: The research method used in this study was an observational analysis with a case-control study approach. A sample of 90 patients consisted of 30 patients diagnosed with malaria as positive cases and 60 patients diagnosed with malaria as negative controls. This research was performed in July 2019. The statistical methods used in this analysis were univariate, bivariate and multivariate analyses. Data gathered through questionnaires and interviews. Results: The bivariate analysis showed a number of risk factors associated with the incidence of malaria in the Elelim Public Health Center in Yalimo District, Papua Province: the use of wire mesh (p = 0.013; RP = 3.237; 95% CI = 1.302-8.047), the type of house wall (p = 0.003; RP = 4.316; 95% CI = 1.696-10.981), the puddle near the house (p = 0.004; RP = 4.333; 95% CI = 1.686-11.138), the distance between house and breading place (p = 0.001; RP = 5.675; 95% CI = 2.097-15.362), the distance between house and large cattle pens (p = 0.042; RP = 2.615; 95% CI = 1.048-6.529), and the use of insecticide net (p = 0.008; RP = 6.000; 95% CI = 1.668-21.583); while age (p = 0.695; RP = 0.740; 95% CI = 0.289-1.897), sex (p = 0.412; RP = 0.474; 95% CI = 0.193-1.165), occupation (p = 0.157; RP = 0.474; 95% CI = 0.193-1.165), education (p = 0.701; RP = 0.750; 95% CI = 0.299-1.878), family income (p = 0.262; RP = 0.546; 95% CI = 0.255-1.325), the use of anti-mosquito repellent (p = 0.705; RP = 1.321; 95% CI = 0.536-3.253), and nighttime habits (p = 0.392; RP = 1.650; 95% CI = 0.668-4.075) were not associated with malaria incidence in the Elelim Public Health Center in Yalimo District, Papua Province

    Impact of a Home-Based Exercise Program on Cardiovascular Disease Biomarkers in Men with Prostate Cancer

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    Patients with prostate cancer (PCa) tend to live a sedentary lifestyle and fail to meet national physical activity requirements putting them at a greater risk for developing weight-related co-morbidities and cancer recurrence. Physical activity after cancer diagnosis is known to improve body composition, physical function, and overall quality of life. The inclusion of a home-based exercise regimen may increase their physical activity and reduce the risk of weight-related illness. PURPOSE: To gather preliminary data regarding the impact of a home-based exercise program on body composition and cardiovascular disease (CVD) biomarkers. METHODS: A single group self-controlled study design was used to test the hypothesis that a home-based exercise program can reduce CVD risk in men with PCa. Fifteen men with PCa under active surveillance were recruited to complete a 24-week home-based exercise program consisting of both aerobic and strength-based exercises. Each week, participants were asked to complete 5 days of light-to-moderate intensity walking at a heart rate reserve of 40-60% and 3 days of bodyweight-based exercises including 3 sets of 15 reps of squats, incline push-ups, and hip thrusts. Serum was collected at baseline and end of study to quantify circulating CVD biomarkers: a-2 macroglobulin (A2M), C-reactive protein (CRP), fetuin-A, a-1 acid glycoprotein (AGP), fibrinogen, L-selectin, serum amyloid P (SAP), platelet factor 4 (PF4/CXCL4), and adipsin using an 8-protein multiplex (Millipore Sigma, Billerica, MA). T-tests were performed with significance established at pRESULTS: A total of 15 men consented and 9 men saw the trial to completion (Age: 72.0 ± 8.52; Weight: 85.31 ± 6.41 kg; BMI: 27.77 ± 2.93 kg/m2). There was a 40% rate of attrition observed due to COVID-19. No significant changes occurred in average weights and BMI from pre to post trial visits. Though not significant, tendencies for increased concentrations of the anticoagulant, A2M (Pre: 99.83 ± 81.19 pg/mL; Post: 126.7 ± 102.5; p=0.064) and the inflammatory protein, SAP (Pre: 0.63 ± 0.32 pg/mL; Post: 0.86 ± 0.46; p=0.09) were seen. We also observed a 1.5-fold increase in CRP (Pre: 0.47 ± 0.38 pg/mL; Post: 1.19 ± 2.209) perhaps, as a result of an increase in SAP, or indicative of increased levels of stress due to COVID-19. No other significant differences were found. CONCLUSION: The reduced sample size may have contributed to the lack of significance found in the analysis. Although there were no statistically significant findings, the tendencies seen in A2M suggest that a home-based exercise program may protect against certain facets of CVD in this overweight population. However, our enthusiasm is blunted by the observed increases in SAP and CRP. Further investigation is necessary to validate these results

    Probing impulsive strain propagation with x-ray pulses

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    Pump-probe time-resolved x-ray diffraction of allowed and nearly forbidden reflections in InSb is used to follow the propagation of a coherent acoustic pulse generated by ultrafast laser-excitation. The surface and bulk components of the strain could be simultaneously measured due to the large x-ray penetration depth. Comparison of the experimental data with dynamical diffraction simulations suggests that the conventional model for impulsively generated strain underestimates the partitioning of energy into coherent modes.Comment: 4 pages, 2 figures, LaTeX, eps. Accepted for publication in Phys. Rev. Lett. http://prl.aps.or

    Effects of a Home-Based Exercise Program on Inflammatory Cytokines and Functional Capacity in Men with Prostate Cancer Under Active Surveillance

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    Regular exercise can improve physical fitness, functional performance, and quality of life in men with prostate cancer (PCa); however, few men with PCa meet national physical activity guidelines. Structured, home-based exercise programs may bridge this gap and increase physical activity in men with PCa. PURPOSE: This pilot study aimed to investigate the impact of a home-based exercise program on cytokines associated with tumor progression in men with PCa. METHODS: A single group, self-controlled study design was used. Fifteen men with PCa under active surveillance were recruited to complete 24 weeks of a home-based exercise program, combining aerobic and body-weight based exercises. The aerobic portion of the intervention included 5 days of light-to-moderate intensity walking for 30 minutes at 40-60% of the participant’s heart rate reserve as calculated using the Karvonen formula. Body-weight based exercises were performed 3 times per week consisting of 3 sets of 15 reps of bodyweight squats, inclined push-ups, and hip thrusts. Serum was collected at baseline and end of study to measure circulating eotaxin, interferon (IFN)Îł, interleukin (IL)-12, IL-1a, IL-5, IL-6, tumor necrosis factor (TNF)-α, and vascular endothelial growth factor (VEGF) cytokines using an 8-protein multiplex (Millipore Sigma, Billerica, MA). A 6-minute walk test (MWT)was completed at the beginning and end of study to measure physical function. T-tests were performed with significance set to p \u3c0.05. RESULTS: A total of 15 men were consented with 9 men completing the intervention (40% attrition due to COVID). At baseline, participants were 70.11 ± 5.42 years of age, weighted 85.31 ± 6.41 kg with a body mass index of 27.77 ± 2.93 kg/m2. A non-significant tendency was observed for improved 6MWT distance (meters) (Pre: 382.7 ± 108.1; Post: 466.7 ± 73.78; p=0.08). Analysis of circulating cytokines showed tendencies for reduced circulating concentrations (pg/mL) of IFNÎł (Pre: 152.9 ± 312.7; Post: 118.9 ± 258.8; p=0.08), and VEGF (Pre: 125.2 ± 198.7; Post: 80.29 ± 124.3; p=0.06) following the intervention. Several other biomarkers showed relevant, though not significant, decreases as well, including IL-12 (Pre: 28.69 ± 32.06; Post: 23.92 ± 19.38; -16.6%), IL-1a (Pre: 78.76 ± 183.3; Post: 65.55 ± 147.7; -16.8%), IL-6 (Pre: 23.71 ± 45.64; Post: 21.24 ± 45.18; -10.4%), and TNF-α (Pre: 24.58 ± 35.4; Post: 19.71 ± 20.76; -19.8%). CONCLUSION: Due to institutional COVID-19 protocols limiting in person research visits, six participants declined to continue the study. The small sample size likely accounts for the lack of statistically significant findings. Although the study did not yield statistically significant outcomes, the results of this study show promising indications that a home-based exercise program could be effective in reducing inflammatory cytokines and increasing functional capacity in men with PCa. Further investigation is needed to confirm these results with a powered sample

    Hydrostatic Compression Behavior and High-Pressure Stabilized ÎČ-Phase in Îł-Based Titanium Aluminide Intermetallics

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    Titanium aluminides find application in modern light-weight, high-temperature turbines, such as aircraft engines, but suffer from poor plasticity during manufacturing and processing. Huge forging presses enable materials processing in the 10-GPa range, and hence, it is necessary to investigate the phase diagrams of candidate materials under these extreme conditions. Here, we report on an in situ synchrotron X-ray diffraction study in a large-volume press of a modern (α2 + Îł) two-phase material, Ti-45Al-7.5Nb-0.25C, under pressures up to 9.6 GPa and temperatures up to 1686 K. At room temperature, the volume response to pressure is accommodated by the transformation Îł → α2, rather than volumetric strain, expressed by the apparently high bulk moduli of both constituent phases. Crystallographic aspects, specifically lattice strain and atomic order, are discussed in detail. It is interesting to note that this transformation takes place despite an increase in atomic volume, which is due to the high ordering energy of Îł. Upon heating under high pressure, both the eutectoid and Îł-solvus transition temperatures are elevated, and a third, cubic ÎČ-phase is stabilized above 1350 K. Earlier research has shown that this ÎČ-phase is very ductile during plastic deformation, essential in near-conventional forging processes. Here, we were able to identify an ideal processing window for near-conventional forging, while the presence of the detrimental ÎČ-phase is not present under operating conditions. Novel processing routes can be defined from these findings. © 2016, Creative Commons

    The United States, PMSCs and the state monopoly on violence: Leading the way towards norm change

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 Sage.The proliferation of private military and security companies (PMSCs) in Iraq and Afghanistan has raised many questions regarding the use of armed force by private contractors. This article addresses the question of whether the increased acceptance of PMSCs indicates a transformation of the international norm regarding the state monopoly on the legitimate use of armed force. Drawing on theoretical approaches to the analysis of norm change, the article employs four measures to investigate possible changes in the strength and meaning of this norm: modifications in state behaviour, state responses to norm violation, the promulgation of varying interpretations of the norm in national and international laws and regulations, and changes in norm discourse. Based on an analysis of empirical evidence from the United States of America and its allies, the article concludes that these measures suggest that the USA is leading the way towards a transformation of the international norm of the state monopoly on violence, involving a revised meaning. Although this understanding has not yet been formally implemented in international law, it has allowed a growing number of countries to tolerate, accept or legalize the use of armed force by PMSCs in the international arena.The Alexander von Humboldt Foundation and the Peace Research Institute Frankfurt
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