Delayed preconditioning-mimetic actions of exercise or nitroglycerin do not affect haemodynamics and exercise performance in trained or sedentary individuals

Abstract

Nitroglycerin induces the so-called second window of protection (SWOP), which alleviates myocardial damage and stunning after ischaemia/reperfusion. To determine whether myocardial performance during exercise is improved in the second window of protection, we studied the haemodynamic responses of 12 trained and 11 sedentary individuals during a sequence of maximal tests on a cycle ergometer. A baseline test (basal test) was followed by a second effort performed during the second window of protection (exercise-SWOP test). Haemodynamics was also evaluated after pharmacologically induced SWOP 48 h after transdermal administration of 10 mg of nitroglycerin (pharmacologically induced SWOP test). The exercise-SWOP and pharmacologically induced SWOP tests were separated by a 1-week washout period. Endothelial-dependent vasodilatation after nitroglycerin pre-treatment was also assessed in five sedentary individuals to determine whether nitrate donors could affect vascular function. We found that nitroglycerin pre-treatment did not induce any improvement in haemodynamics in either trained or sedentary individuals, since maximum values of workload, heart rate, stroke volume, cardiac output, myocardial contractility, and double product were similar between the exercise-SWOP and pharmacologically induced SWOP tests in both groups. Furthermore, nitroglycerin pre-treatment did not alter flow-mediated dilation during pharmacologically induced SWOP. Although nitroglycerin pre-treatment alleviates post-ischaemic myocardial stunning, our results suggest that it does not affect the myocardial performance of healthy individuals during exercise performed in the second window of protection, independently of the training status of the individuals. Moreover, nitroglycerin pre-treatment does not ameliorate endothelial function.     

Effect of custom-made and prefabricated insoles on plantar loading parameters during running with and without fatigue

Abstract

Controversy exists whether custom-made insoles are more effective in reducing plantar loading compared to prefabricated insoles. Forty recreational athletes ran using custom-made, prefabricated, and the original insoles of their running shoes, at rest and after a fatigue run. Contact time, stride rate, and plantar loading parameters were measured. Neither the insole conditions nor the fatigue state modified contact time and stride rate. Addressing prevention of running injuries, post-fatigue loading values are of great interest. Custom-made insoles reduced the post-fatigue loading under the hallux (92 vs. 130 kPa, P < 0.05), medial midfoot (70 vs. 105 kPa, P < 0.01), and lateral midfoot (62 vs 96 kPa, P < 0.01). Prefabricated insoles provoked reductions in post-fatigue loading under the toes (120 vs. 175 kPa, P < 0.05), medial midfoot (71 vs. 105 kPa, P < 0.01), and lateral midfoot (68 vs. 96 kPa, P < 0.01). Regarding both study insoles, custom-made insoles reduced by 31% and 54% plantar loading under the medial and lateral heel compared to the prefabricated insoles. Finally, fatigue state did not influence plantar loading regardless the insole condition. In long-distance races, even a slight reduction in plantar loading at each foot strike may suppose a significant decrease in the overall stress experienced by the foot, and therefore the use of insoles may be an important protective mechanism for plantar overloading.     

Identification of histological threshold concepts in health sciences curricula: Students' perception

Students' metacognitive skills and perceptions are considered important variables for high-quality learning. In this study, students' perceptions were used to identify histological threshold concepts (integrative, irreversible, transformative, and troublesome) in three health sciences curricula. A specific questionnaire was developed and validated to characterize students' perceptions of histological threshold concepts. A sample of 410 undergraduate students enrolled in the dentistry, medicine, and pharmacy degree programs participated in the study. Concepts assessed in the study were clustered to ten categories (factors) by exploratory and confirmatory factor analysis. Concepts linked to tissue organization and tissue functional states received the highest scores from students in all degree programs, suggesting that the process of learning histology requires the integration of both static concepts related to the constituent elements of tissues and dynamic concepts such as stem cells as a tissue renewal substrate, or the euplasic, proplasic and retroplasic states of tissues. The complexity of integrating static and dynamic concepts may pose a challenging barrier to the comprehension of histology. In addition, several differences were detected among the students in different degree programs. Dentistry students more often perceived morphostructural concepts as threshold concepts, whereas medical students highlighted concepts related to two-dimensional microscopic identification. Lastly, pharmacy students identified concepts related to tissue general activity as critical for the comprehension and learning of histology. The identification of threshold concepts through students' perceptions is potentially useful to improve the teaching and learning process in health sciences curricula.     

Initiating running barefoot: Effects on muscle activation and impact accelerations in habitually rearfoot shod runners

Runners tend to shift from a rearfoot to a forefoot strike pattern when running barefoot. However, it is unclear how the first attempts at running barefoot affect habitually rearfoot shod runners. Due to the inconsistency of their recently adopted barefoot technique, a number of new barefoot-related running injuries are emerging among novice barefoot runners. The aim of this study was therefore to analyse the influence of three running conditions (natural barefoot [BF], barefoot with a forced rearfoot strike [BRS], and shod [SH]) on muscle activity and impact accelerations in habitually rearfoot shod runners. Twenty-two participants ran at 60% of their maximal aerobic speed while foot strike, tibial and head impact accelerations, and tibialis anterior (TA), peroneus longus (PL), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscle activity were registered. Only 68% of the runners adopted a non-rearfoot strike pattern during BF. Running BF led to a reduction of TA activity as well as to an increase of GL and GM activity compared to BRS and SH. Furthermore, BRS increased tibial peak acceleration, tibial magnitude and tibial acceleration rate compared to SH and BF. In conclusion, 32% of our runners showed a rearfoot strike pattern at the first attempts at running barefoot, which corresponds to a running style (BRS) that led to increased muscle activation and impact accelerations and thereby to a potentially higher risk of injury compared to running shod.     

Health Sciences Patron Preference for Library Spaces: A Multisite Observational Study

Health sciences libraries are often challenged to make decisions regarding physical space allocation without quantitative data to support specific user preferences. This multisite, longitudinal study sought to answer the following questions related to academic health sciences libraries: (1) Which library spaces are popular with health sciences patrons? (2) How does time of day and allocated seating space affect patron choices? (3) What similarities and differences occur in space usage across four different health sciences libraries? Results suggest health sciences libraries must develop a nuanced understanding of their patrons’ preferences to best serve patrons’ needs regarding space allocation. Libraries can benefit from these types of methodological studies that target specific populations, supporting more informed space allocation decision making.     

The contribution of non-formal learning in higher education to student teachers’ professional competence

This article reports a mixed methods study on the contribution of various aspects of pre-service student teachers’ learning in initial teacher education (ITE) to their professional competence in a Five-year Bachelor of Education Programme in Hong Kong. Special attention is given to how student teachers’ non-formal learning in higher education contributes to their professional competence, an under-researched area in teacher education. A total of 282 student teachers participated in the quantitative survey, 18 of whom were interviewed. Although  Undergraduate Learning Experience: Formal Learning and Non-formal Learning was not the most highly rated factor, multiple regression indicated that it was the only ITE professional learning factor that significantly predicted all dimensions of professional competence. This supports the hypothesis that non-formal learning as a part of learning in higher education makes a significant contribution to student teachers’ professional competence. The qualitative findings showed that non-formal learning provided opportunities for service learning, co-curricular activities, and student exchange programmes with different objects of engagement. Student teachers constructed pedagogical content knowledge, general pedagogical knowledge, and knowledge of context through hands-on experiences, professional dialogue with practitioners, and observations of others’ practice. Such knowledge contributed to their competence in classroom teaching and to work in schools. Implications for ITE are discussed.     

A seventeenth century Japanese painting: Scientific identification of materials and techniques

A Japanese painting on paper, in the form of a horizontal scroll from the Stibbert Museum in Florence, is being treated at the ISCR Paper Conservation Laboratory. The scroll, entitled Bamo Dōi-zu represents 33 different types of horses. Although there is no author's seal, it has been attributed to the famous Japanese artist, Kanō Sansetsu (1589–1651). Before conservation treatment, the artefact underwent technical and scientific examination in order to identify its materials and determine its conservation condition. As sampling paint layers from paintings on paper is extremely invasive, non-destructive techniques such as X-ray fluorescence spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and spectrophotometry were employed. Several points from the paper support were analysed: the metal-leaf decorations, the seals and calligraphy, as well as the painted horses. Results detected and revealed a very simple palette: cinnabar (or its synthetic equivalent vermillion), shell white, carbon black, and the organic yellow gamboge. Pure gold and silver leaves were used for decorating the frontispiece. Useful information was obtained from the paper support and on its conservation conditions. Micro-destructive analyses were also performed on a few paper fragments for microscopic and scanning electron microscope equipped with an X-ray probe analysis. Results showed that materials and techniques are consistent with the Kanō School period.     

2011中网宣传片幕后花絮：我就在这里

2011年3月24日,ATP大师赛与WTA一级赛正在阳光之城迈阿密火热进行中。在距离比赛场地不过5分钟车程的利兹·卡尔顿酒店内,一个供拍摄使用的专业摄影棚已经搭建完成,著名的网球摄影师罗·安吉与凯利·巴克正在调试器材,难道赛场之外也将有网球的故事发生？