The reproducibility of perceptually regulated exercise responses during short-term cycle ergometry

This is the author's PDF version of an article published in International journal of sports medicine in 2004. The definitive version is available at www.thieme-connect.com.The purpose of this study was to assess the reproducibility over four trials of perceptually regulated exercise intensity during short-term cycle ergometry. Recent research has suggested that an improvement in the reproducibility (better agreement) of the exercise output would be observed with a repeated practice of using regulatory tools such as Borg’s 6-20 rating of perceived exertion (RPE) scale. Eighteen healthy active volunteers (nine males mean age (± SD) 24.7 ± 3.4 yr, and nine females 27.6 ± 5.4 yr) completed four identical intermittent effort production trials on a cycle ergometer, over a period of two-three weeks, with all trials being between three and five days apart. After warm-up, the volunteers were asked to produce four x three-minute bouts of exercise at RPE levels: 13, 15, 9, and 17 (in this order). Power output (W), percentage maximum heart rate reserve (%MHRR), and oxygen consumption (VO2; ml•kg-1•min-1) were recorded in the final minute of each bout. Analysis revealed that the 95% limits of agreement (LoA) between repeated trials did not decrease for the objective markers of exercise intensity, remaining wide throughout. In the worst case comparisons the LoA represented changes (expressed as a proportion of the mean of two trials) of up to 58.3% in power output (T2 vs. T3 at RPE 9), 65.5% in %MHRR (T1 vs. T2 at RPE 13) and 36.5% in VO2 (T3 vs. T4 at RPE 17). These findings question the use of ratings of perceived exertion to regulate exercise effort. That the reproducibility of effort is also not seen to improve with practice raises doubts over the validity of using the RPE scale for providing training intensities for this type of exercise.This article was submitted to the RAE2008 for the University of Chester - Allied Health Professions and Studies

Analytic Examples, Measurement Models and Classical Limit of Quantum Backflow

We investigate the backflow effect in elementary quantum mechanics - the phenomenon in which a state consisting entirely of positive momenta may have negative current and the probability flows in the opposite direction to the momentum. We compute the current and flux for states consisting of superpositions of gaussian wave packets. These are experimentally realizable but the amount of backflow is small. Inspired by the numerical results of Penz et al (M.Penz, G.Gr\"ubl, S.Kreidl and P.Wagner, J.Phys. A39, 423 (2006)), we find two non-trivial wave functions whose current at any time may be computed analytically and which have periods of significant backflow, in one case with a backwards flux equal to about 70 percent of the maximum possible backflow, a dimensionless number $c_{bm} \approx 0.04$, discovered by Bracken and Melloy (A.J.Bracken and G.F.Melloy, J.Phys. A27, 2197 (1994)). This number has the unusual property of being independent of $\hbar$ (and also of all other parameters of the model), despite corresponding to an obviously quantum-mechanical effect, and we shed some light on this surprising property by considering the classical limit of backflow. We discuss some specific measurement models in which backflow may be identified in certain measurable probabilities.Comment: 33 pages, 14 figures. Minor revisions. Published versio

Factors associated with growth in daily smoking among Indigenous adolescents

North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group, yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10-13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder, were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker. © 2012 The Authors. Journal of Research on Adolescence © 2012 Society for Research on Adolescence

Viral evasion of innate immune defense: The case of resistance of pandemic H1N1 influenza A virus to human mannose-binding proteins

Mannose-binding lectins effectively inhibit most seasonal strains of influenza A virus and contribute to the innate host defense vs. these viruses. In contrast, pandemic IAV strains are largely resistant to these lectins, likely contributing to increased spread and worse outcomes. In this paper, we evaluated the inhibition of IAV by mannose-binding lectins of human, bacterial, and fungal origin to understand and possibly increase activity vs. the pandemic IAV. A modified version of the human surfactant protein D (SP-D) neck and carbohydrate recognition domain (NCRD) with combinatorial substitutions at the 325 and 343 positions, previously shown to inhibit pandemic H3N2 IA

Tetranectin Binds to the Kringle 1-4 Form of Angiostatin and Modifies Its Functional Activity

Tetranectin is a plasminogen kringle 4 domain-binding protein present in plasma and various tissue locations. Decreased plasma tetranectin or increased tetranectin in stroma of cancers correlates with cancer progression and adverse prognosis. A possible mechanism through which tetranectin could influence cancer progression is by altering activities of plasminogen or the plasminogen fragment, angiostatin. Tetranectin was found to bind to the kringle 1-4 form of angiostatin (AST(K1-4)). In addition, tetranectin inhibited binding of plasminogen or AST(K1-4) to extracellular matrix (ECM) deposited by endothelial cells. Finally, tetranectin partially counteracted the ability of AST(K1-4) to inhibit proliferation of endothelial cells. This latter effect of tetranectin was specific for AST(K1-4) since it did not counteract the antiproliferative activities of the kringle 1-3 form of angiostatin (AST(K1-3)) or endostatin. These findings suggest that tetranectin may modulate angiogenesis through interactions with AST

Alzheimer's Associated β-Amyloid Protein Inhibits Influenza A Virus and Modulates Viral Interactions with Phagocytes

Accumulation of β-Amyloid (βA) is a key pathogenetic factor in Alzheimer's disease; however, the normal function of βA is unknown. Recent studies have shown that βA can inhibit growth of bacteria and fungi. In this paper we show that βA also inhibits replication of seasonal and pandemic strains of H3N2 and H1N1 influenza A virus (IAV) in vitro. The 42 amino acid fragment of βA (βA42) had greater activity than the 40 amino acid fragment. Direct incubation of the virus with βA42 was needed to achieve optimal inhibition. Using quantitative PCR assays βA42 was shown to reduce viral uptake by epithelial cells after 45 minutes and to reduce supernatant virus at 24 hours post infection. βA42 caused aggregation of IAV particles as detected by light transmission assays and electron and confocal microscopy. βA42 did not stimulate neutrophil H2O2 production or extracellular trap formation on its own, but it increased both responses stimulated by IAV. In addition, βA42 increased uptake of IAV by neutrophils. βA42 reduced viral protein synthesis in monocytes and reduced IAV-induced interleukin-6 production by these cells. Hence, we demonstrate for the first time that βA has antiviral activity and modulates viral interactions with phagocytes

Demonstration of a discharge pumped table-top soft-x-ray laser

Includes bibliographical references (page 2195).Includes errata.We report the first observation of large soft-x-ray amplification (gl = 7.2) in a discharge-created plasma. A fast, ~40 kA, current pulse from a compact discharge was used to excite plasma columns up to 12 cm in length in 4-mm channels, producing population inversion in the J = 0-1 line of Ne-like Ar and resulting in a gain of 0.6 cm-1 at 46.9 nm. The beam divergence was measured to be <9 mrad

Reduced influenza viral neutralizing activity of natural human trimers of surfactant protein D

BACKGROUND. Surfactant protein D (SP-D) plays important roles in innate host defense against influenza A virus (IAV) infection. Common human polymorphisms of SP-D have been found in many human populations and associated with increased risk of certain infections. We recently reported that the Thr/Thr 11 form of SP-D is associated with low serum levels and assembles predominantly as trimers as opposed to the more common multimeric forms of SP-D. METHODS. Preliminary experiments were done to establish the effects of different monoclonal antibodies against SP-D on ability of SP-D to bind to or neutralize the virus. We then purified natural human trimeric and multimeric forms of SP-D from amniotic fluid and tested ability of these preparations to bind to IAV, to inhibit infectivity and hemagglutination activity of IAV in vitro. RESULTS. In initial experiments mAbs directed against different areas on the CRD of SP-D were found to have differing effects on antiviral activity. Using an mAb that did not interfere with antiviral activity of SP-D, we confirm that natural SP-D trimers had reduced ability to bind to IAV. In addition, the trimers had reduced ability to neutralize IAV as compared to natural human SP-D multimers as well as reduced hemagglutination inhibiting activity against several strains of IAV. Natural SP-D trimers also had different interactions with human neutrophil peptide defensins (HNPs) in viral neutralization assays as compared to multimeric SP-D. CONCLUSION. These studies indicate that a common human polymorphic form of SP-D may modulate host defense against IAV and give impetus to clinical studies correlating this genotype with risk for IAV infection in susceptible groups. We also show that mAbs directed against different areas on the carbohydrate recognition domain of SP-D can be useful for dissecting out different functional properties of the protein

Neighborhood Characteristics and Colorectal Cancer Survivors\u27 Quality of Care

Purpose: Quality cancer care entails receipt of a Survivorship Care Plan (SCP). The purpose of this study was to determine differences in SCP delivery by patient-level and neighborhood characteristics. Methods: We obtained California cancer registry data on individuals who were diagnosed with stage I, II, or III colorectal cancer (CRC) between 2012 and 2015 and resided in predetermined geographic areas. We then mailed them a questionnaire, which queried about receipt of a SCP and its content. SCP was defined by content, as summary of cancer treatment, cancer surveillance recommendations, and/or an individualized preventive care. Using logistic regression modeling, each measure of SCP, as well as the summary measure (none vs. any), was evaluated by person-level characteristics. Subsequently, neighborhood-level characteristics were added to the model to explore their additional value. Results: Overall 80% of CRC survivors received a SCP. Receipt of SCPs was associated with person-level characteristics, while neighborhood characteristics did not make an additional contribution. Young, male employed survivors and those with more recent diagnoses or later cancer stages had greater odds of receiving a SCP. Conclusion: When providing SCPs, health care providers prioritize patient groups who they may perceive as vulnerable or likely to benefit from SCPs

Gaps present a trade-off between dispersal and establishment that nourishes species diversity

We took advantage of two natural experiments to investigate processes that regulate tree recruitment in gaps. In the first, we examined the recruitment of small and large saplings and trees into 31 gaps resulting from treefalls occurring between 1984 and 2015 in the 2.25-ha core area of a 4-ha tree plot at Cocha Cashu in Peru. In the second, we identified the tallest saplings recruiting into 69 gaps created during a violent wind storm in February 2000. In the established tree plot, we were able to compare the composition of saplings in the disturbance zones of gaps prior to, during, and subsequent to the period of gap formation. Recruitment in gaps was compared with that in "nofall" zones, areas within the plot that had not experienced a treefall at least since the early 1980s. Our results confirmed earlier findings that a consistently high proportion (~60%) of established saplings survived gap formation. Light demanding species, as proxied by mortality rates, recruited under all conditions, but preferentially during periods of gap formation, a pattern that was especially strong among gap pioneers. Similar results were noted, separately, for small and large saplings and trees recruiting at >= 10 cm dbh. One hundred percent of previously untagged trees recruiting into gaps in the first post-disturbance census were gap pioneers, suggesting rapid development. This conclusion was strongly supported in a follow-up survey taken of 69 gaps 19 months after they had been synchronously created in a wind storm. Ten species of gap pioneers, eight of which are not normally present in the advance regeneration, had attained heights of 6-10 m in 19 months. The 10 gap pioneers were dispersed, variously, by primates, bats, birds, and wind and reached maximum frequency in different-sized gaps (range 1,000 m(2)). Both gap size and limited dispersal of zoochorous species into gaps serve as filters for establishment, creating a complex mosaic of conditions that enhances species diversity