Temperature-dependent release of ATP from human erythrocytes: Mechanism for the control of local tissue perfusion

Copyright @ 2012 The AuthorsThis article has been made available through the Brunel Open Access Publishing Fund.Human limb muscle and skin blood flow increases significantly with elevations in temperature, possibly through physiological processes that involve temperature-sensitive regulatory mechanisms. Here we tested the hypothesis that the release of the vasodilator ATP from human erythrocytes is sensitive to physiological increases in temperature both in vitro and in vivo, and examined potential channel/transporters involved. To investigate the source of ATP release, whole blood, red blood cells (RBCs), plasma and serum were heated in vitro to 33, 36, 39 and 42°C. In vitro heating augmented plasma or ‘bathing solution’ ATP in whole blood and RBC samples, but not in either isolated plasma or serum samples. Heat-induced ATP release was blocked by niflumic acid and glibenclamide, but was not affected by inhibitors of nucleoside transport or anion exchange. Heating blood to 42°C enhanced (P < 0.05) membrane protein abundance of cystic fibrosis transmembrane conductance regulator (CFTR) in RBCs. In a parallel in vivo study in humans exposed to whole-body heating at rest and during exercise, increases in muscle temperature from 35 to 40°C correlated strongly with elevations in arterial plasma ATP (r2 = 0.91; P = 0.0001), but not with femoral venous plasma ATP (r2 = 0.61; P = 0.14). In vitro, however, the increase in ATP release from RBCs was similar in arterial and venous samples heated to 39°C. Our findings demonstrate that erythrocyte ATP release is sensitive to physiological increases in temperature, possibly via activation of CFTR-like channels, and suggest that temperature-dependent release of ATP from erythrocytes might be an important mechanism regulating human limb muscle and skin perfusion in conditions that alter blood and tissue temperature.This article is made available through the Brunel Open Access Publishing Fund

Temperature-Induced Changes in the Oxygen Equilibrium Curve of the Blood of the Brown Bullhead, Ictalurus Nebulosus

The affinity of blood for oxygen is dependent on temperature, which would seem to present a disadvantage to those fishes which encounter large seasonal temperature changes. Considering the well-known acclimatory abilities of many fishes, it would seem reasonable to propose the occurrence of seasonal modification of blood oxygen equilibria to compensate for changes in temperature. 2. In Ictalurus nebulosus, blood from one group of fish acclimated at 24 degrees C showed a consistently higher oxygen affinity compared with a group acclimated at 9 degrees C, when measured at the same temperature. This shift, accompanying thermal metabolic acclimation, minimizes the effect of temperature on oxygen affinity. 3. The shift did not persist when dilute solutions of hemoglobin were studied. 4. No changes with acclimation were seen in the multiple hemoglobin pattern nor in blood pH. 5. The erythrocyte, rather than the plasma, appears to be the site of modification. 6. Some large changes in erythrocyte potassium accompanied thermal acclimation, but the relation of this to the shift in oxygen affinity is unknown

Reverse production effect: Children recognize novel words better when they are heard rather than produced

This is the peer reviewed version of the following article: Tania S. Zamuner, Stephanie Strahm, Elizabeth Morin-Lessard, and Michael P. A. Page, 'Reverse production effect: children recognize novel words better when they are heard rather than produced', Developmental Science, which has been published in final form at DOI 10.1111/desc.12636. Under embargo until 15 November 2018. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.This research investigates the effect of production on 4.5- to 6-year-old children’s recognition of newly learned words. In Experiment 1, children were taught four novel words in a produced or heard training condition during a brief training phase. In Experiment 2, children were taught eight novel words, and this time training condition was in a blocked design. Immediately after training, children were tested on their recognition of the trained novel words using a preferential looking paradigm. In both experiments, children recognized novel words that were produced and heard during training, but demonstrated better recognition for items that were heard. These findings are opposite to previous results reported in the literature with adults and children. Our results show that benefits of speech production for word learning are dependent on factors such as task complexity and the developmental stage of the learner.Peer reviewedFinal Accepted Versio

Working with Birth to Three: Exploring the Personal Theories of Early Years Practitioners

Practitioners working with children under three are often marginalised; both in terms of group settings and in terms of being a focus of research (see Manning-Morton, 2006; McDowell-Clark and Baylis, 2012). This research prioritizes the practitioner’s voice by exploring the subject area of personal theory. In this thesis, personal theory is conceptualised as a composite of understandings and experiences including policy, organisational procedures, Early Years literature, training and Continuing Professional Development as well as personal and professional experiences, beliefs, and values. As Stephen and Brown (2004) indicate, particular constructions of care, learning, and children shape what is considered desirable educational practice. Drawing on Aristotle’s intellectual virtue of phronesis, this research’s aim is to understand how practitioners’ personal and professional experiences and understandings contribute to practitioners’ construction of personal theory. Research questions focus on: 1) understanding which relationships are particularly influential, 2) understanding which experiences are particularly influential and 3) identifying key features of practitioners’ personal theories. Case study methodology frames the research design. The research demonstrates that although personal theory is tacit, linking to specific instances of practice enables practitioners to articulate personal constructions of care, learning and children. Findings relate to six key characteristics of practitioners’ personal theories: practice as an ‘Ethic of Care’, practice as pedagogy, practice as ‘subsitute mothering’, practice as distinctive for children aged birth to three years, practice as rooted in experience and practice as emotional activity. Joan Tronto’s (1993, 2013) ‘Ethic of Care’ affords further consideration of personal theory; particularly the contradiction between personal theory that shapes engagements with young children as an ‘Ethic of Care’ and that which shapes engagements as ‘substitute mothering’. The thesis’ discussion highlights how the articulation and discussion of personal theory enables a richer construction of Early Years professionalism and professional identity within Birth to Three settings

The reflection coefficient at the truncated corner of a rectangular wave guide

The term wave guide refers to a hollow conducting tube (usually of rectangular or circular cross section) filled with a dielectric (or vacuum) and used for the transmission of electromagnetic waves. We shall consider the guide to be bounded by a perfect conductor and to be filled with a lossless homogeneous isotropic dielectric (or vacuum). The electromagnetic wave in the guide must of course satisfy Maxwell\u27s equation. It must also satisfy the boundary condition that there be no tangential component of electric field at the surface of the conductor. If the electromagnetic waves traveling along the guide meet a discontinuity or irregularity in the guide then there will be a part of the energy reflected back in the direction from which it came and a part of the energy transmitted on down the guide...The present paper considers the TE₁,₀ mode with the electric vector normal to the plane of the corner. Equations are derived involving the amplitudes of the reflected and transmitted waves and an infinite series of constants. It is hoped that in the consideration of specific cases it will be possible to obtain approximate numerical values of the amplitudes of the reflected and transmitted waves by using only a finite and practical number of terms in the infinite series, although time has not permitted an attempt to carry out any actual numerical computations in this thesis --Introduction, page 1-3

Examining the Impact of Student Engagement on Academic Persistence and Academic Performance among First-Generation College Freshman Students at Four-Year Public Institutions

This study examines the impact of student engagement on academic persistence and academic performance among first-generation college freshman students at four-year public institutions. With approximately 50 percent of college students identifying as first-generation, this demographic faces unique challenges that contribute to lower retention rates and academic outcomes compared to their continuing-generation peers. Utilizing secondary data from the National Survey of Student Engagement (NSSE) collected in 2016, 2019, and 2021, and institutional student records from a large, public, urban R2 Doctoral University in the Southeast, this quantitative study employs multiple regression and binary logistic regression analyses to assess the relationships between student engagement, academic performance, and academic persistence. Findings indicate that first-generation students are significantly less likely to persist into their sophomore year and have lower GPAs than their continuing-generation peers. Key engagement factors, including learning strategies, supportive environments, and faculty interaction, were identified as predictors of academic success. However, interaction effects between first-generation status and the NSSE engagement indicators were not statistically significant, suggesting that while engagement benefits all students, its impact on persistence and performance odes not differ significantly between first-generation and continuing-generation students. This study contributes to the literature on student engagement and first-generation student success, and the results have practical implications for higher education administrators seeking to enhance retention strategies and academic support services tailored to first-generation college students