The effect of caffeine on high-intensity, intermittent exercise to exhaustion

Caffeine has been proported to increase endurance exercise time to exhaustion. However, the effects of caffeine on high-intensity, intermittent exercise to exhaustion have not been widely studied. Therefore, the purpose of this study was to examine the effect of caffeine on intermittent, high intensity exercise to exhaustion in individuals with minimal daily dietary caffeine consumption. Seven male participants, age 26 {dollar}\pm{dollar} 2 years, body mass 77 {dollar}\pm{dollar} 11 kg, and VO2{dollar}\rm\sb{max}{dollar} 47 {dollar}\pm{dollar} 7 ml/kg/min, performed a high-intensity exercise bout under both caffeine and placebo conditions administered in a counterbalanced, double blind fashion. Participants cycled at 120% of peak power output for 60 seconds followed by 120 seconds of recovery at 50 Watts. Work/rest cycles continued until voluntary exhaustion. Blood samples were taken immediately prior to administering caffeine or placebo beverages, one hour post absorption, and immediately following the conclusion of the exercise test. No significant difference in time to exhaustion was found between caffeine and placebo trials (12.5 {dollar}\pm{dollar} 5.9 vs 12.3 {dollar}\pm{dollar} 6.6 min), nor did peak blood lactate concentration differ between trials (11.3 {dollar}\pm{dollar} 1.0 vs 11.6 {dollar}\pm{dollar} 1.9 mM). These results suggest that caffeine treatment provides no significant improvement in performance time during intermittent, high-intensity exercise to exhaustion

The WTO Dispute Settlement Review Commission: An Unwise Extension of Extrajudicial Roles

In the past decade, Congress has enlisted the Federal Judiciary to deal with issues ranging from the appointment of special prosecutors to the development of standardized sentencing guidelines. One area of particular focus has been international trade. In November, 1995, then Senate Majority Leader Robert Dole introduced Senate Bill 1438 (S. 1438) which\u27 calls for a five-member panel, comprised of active federal circuit judges, to review all World Trade Organization (WTO) dispute resolution decisions adverse to the United States\u27 economic interests. In this Note, the author employs the separation of powers doctrine to examine both the constitutionality and the wisdom of utilizing federal judges to review WTO decisions. The author delineates the long-standing practice of extra-judicial service by federal judges. Next, by comparing this proposal with the Supreme Court\u27s decisions addressing extrajudicial activity, the author concludes that the Court would likely uphold the constitutionality of S. 1438. However, the wisdom of the proposed Commission is not as apparent. The policy implications of embroiling federal judges in the politics of the WTO and the greater debate over United States\u27 sovereignty would have a wholly detrimental effect on the judicial branch

Relaxation behavior of dense suspensions

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020Cataloged from the official PDF of thesis.Includes bibliographical references (pages 16-17).Dense suspensions of solid particles in Newtonian fluids exhibit a variety of non-Newtonian behaviors depending on the shear stress applied to the suspension and the particle mass fraction ([mathematical symbol]m). Suspensions at sufficiently high fm shear-thicken dramatically and eventually shear jam, showing behaviors typified by solids. But, little is known about how dense suspensions relax out of this stressed rheological state. To understand the relaxation behavior of a cornstarch/water dense suspension, samples are prepared at different fm, in the range that shows dramatic shear thickening, between 54.5% and 58.5% cornstarch. Each sample is formed into drops and kept in the stressed state through dynamic shearing using a B&K permanent magnet shaker, then allowed to relax. We show that dense suspensions relax with two distinct timescales. A short timescale that is independent of [mathematical symbol]m, denoting the settling of the drop onto the flat surface, and a longer timescale that is governed by the viscosity of the dense suspension and increases as [mathematical symbol]m increases above 55.75%. Our work provides an understanding of how a dense suspension relaxes out of a shear-thickened state.by Andrew Herman Griese.S.B.S.B. Massachusetts Institute of Technology, Department of Mechanical Engineerin

Fluorescence-Activated Cell Sorting and Quantitative Real-Time PCR to Reveal VEGF-Expressing Macrophage Populations in the Zebrafish Larvae

The transparent, genetically tractable zebrafish is increasingly recognized as a useful model to both live image and uncover mechanistic insight into cell interactions governing tissue homeostasis, pathology, and regeneration. Here, we describe a protocol for the isolation of macrophages from zebrafish wounds using fluorescence-activated cell sorting (FACS), and the identification of specific pro-angiogenic macrophage populations that express high levels of vascular endothelial growth factor (vegf) using quantitative real-time PCR (qPCR). The cell dissociation and FACS sorting techniques have been optimized for immune cells and successfully used to isolate other fluorescently marked populations within the wound such as neutrophils and endothelial cells. More broadly, this protocol can be easily adapted to other contexts where identification of pro-angiogenic immune cells is transformative for understanding, from development to pathologies such as infection, cancer, and diabetes.</p

Hyperspectral imaging in biomedical applications

No abstract available

Muscarinic receptor signaling in the pathophysiology of asthma and COPD

Anticholinergics are widely used for the treatment of COPD, and to a lesser extent for asthma. Primarily used as bronchodilators, they reverse the action of vagally derived acetylcholine on airway smooth muscle contraction. Recent novel studies suggest that the effects of anticholinergics likely extend far beyond inducing bronchodilation, as the novel anticholinergic drug tiotropium bromide can effectively inhibit accelerated decline of lung function in COPD patients. Vagal tone is increased in airway inflammation associated with asthma and COPD; this results from exaggerated acetylcholine release and enhanced expression of downstream signaling components in airway smooth muscle. Vagally derived acetylcholine also regulates mucus production in the airways. A number of recent research papers also indicate that acetylcholine, acting through muscarinic receptors, may in part regulate pathological changes associated with airway remodeling. Muscarinic receptor signalling regulates airway smooth muscle thickening and differentiation, both in vitro and in vivo. Furthermore, acetylcholine and its synthesizing enzyme, choline acetyl transferase (ChAT), are ubiquitously expressed throughout the airways. Most notably epithelial cells and inflammatory cells generate acetylcholine, and express functional muscarinic receptors. Interestingly, recent work indicates the expression and function of muscarinic receptors on neutrophils is increased in COPD. Considering the potential broad role for endogenous acetylcholine in airway biology, this review summarizes established and novel aspects of muscarinic receptor signaling in relation to the pathophysiology and treatment of asthma and COPD

Bayes estimates of the cyclical component in twentieth centruy US gross domestic product

Cyclical components in economic time series are analysed in a Bayesian framework, thereby allowing prior notions about periodicity to be used. The method is based on a general class of unobserved component models that encompasses a range of dynamics in the stochastic cycle. This allows for instance relatively smooth cycles to be extracted from time series. Posterior densities of parameters and estimated components are obtained using Markov chain Monte Carlo methods, which we develop for both univariate and multivariate models. Features such as time-varying amplitude may be studied by examining different functions of the posterior draws for the cyclical component and parameters. The empirical application illustrates the method for annual US real GDP over the last 130 years

Trends and cycles in economic time series: A Bayesian approach

Trends and cyclical components in economic time series are modeled in a Bayesian framework. This enables prior notions about the duration of cycles to be used, while the generalized class of stochastic cycles employed allows the possibility of relatively smooth cycles being extracted. The posterior distributions of such underlying cycles can be very informative for policy makers, particularly with regard to the size and direction of the output gap and potential turning points. From the technical point of view a contribution is made in investigating the most appropriate prior distributions for the parameters in the cyclical components and in developing Markov chain Monte Carlo methods for both univariate and multivariate models. Applications to US macroeconomic series are presented