THE EFFECT OF VISUAL GAZE LOCATION ON BLOCK-START BIOMECHANICS IN ATHLETICS

This study investigated the effects of varying visual gaze location (VGL), by means of externally-focused instruction, during the block-start “set” phase with the intention of optimizing block-start biomechanics for faster starts in an athlete-specific manner. Nine collegiate sprinters performed a series of block-starts while directing their VGL to their personal baselines, and at 0.5m, 1m, 2m and 3m from the start line. Twelve infrared opto-reflective cameras and one force plate were utilized to assess trunk, hip, knee and centre of mass kinematics, and blocks push-phase kinetics. An eyetracker was used to determine participants’ VGL. Some postural changes observed were a significant decrease in pelvic height in the “set” position, and more upright trunk postures at toe-off from the blocks, when participants gazed further at 2m and 3m. Gazing at 1m was effective in eliciting changes to pelvic horizontal velocity. These results suggest that manipulating VGL could help certain athletes to optimize their block-start biomechanics for faster starts. Coaches can consider redirecting VGL in addition to usual instructional methods to improve the block-start performances of athletes

Ultrasensitive Detection of MCF-7 Cells with a Carbon Nanotube-Based Optoelectronic-Pulse Sensor Framework

Biosensors are of vital significance for healthcare by supporting the management of infectious diseases for preventing pandemics and the diagnosis of life-threatening conditions such as cancer. However, the advancement of the field can be limited by low sensing accuracy. Here, we altered the bioelectrical signatures of the cells using carbon nanotubes (CNTs) via structural loosening effects. Using an alternating current (AC) pulse under light irradiation, we developed a photo-assisted AC pulse sensor based on CNTs to differentiate between healthy breast epithelial cells (MCF-10A) and luminal breast cancer cells (MCF-7) within a heterogeneous cell population. We observed a previously undemonstrated increase in current contrast for MCF-7 cells with CNTs compared to MCF-10A cells with CNTs under light exposure. Moreover, we obtained a detection limit of ∼1.5 × 10^{3} cells below a baseline of ∼1 × 10^{4} cells for existing electrical-based sensors for an adherent, heterogeneous cell population. All-atom molecular dynamics (MD) simulations reveal that interactions between the embedded CNT and cancer cell membranes result in a less rigid lipid bilayer structure, which can facilitate CNT translocation for enhancing current. This as-yet unconsidered cancer cell-specific method based on the unique optoelectrical properties of CNTs represents a strategy for unlocking the detection of a small population of cancer cells and provides a promising route for the early diagnosis, monitoring, and staging of cancer

Fostering Self-Authorship and Changemaking: Insights from a Social Entrepreneurship Practicum

The question we are explore in this paper is how a collaboration between a practicum-based course and a social enterprise encourages students to examine, discuss, and apply complex social justice concepts and frameworks. We also investigate how this fosters in them a sense of self as changemaker, a form of self-authorship that includes the confidence to tackle justice issues in collaborative and practical ways. Applying the framing of Baxter Magolda’s Learning Partnerships Model, we first describe our experiential pedagogical practice and then illustrate outcomes by drawing exemplars from student reflections. These reflections confirm that a community-based learning practice can support students to become changemakers able to analyze the systemic forces that give rise to injustices, engage in honest dialogue to understand multiple perspectives, cultivate trusting relationships across differences of identity and experience, and feel confidence in themselves and others to create meaningful change toward a more just world

Effect of rosiglitazone on progression of atherosclerosis: insights using 3D carotid cardiovascular magnetic resonance

<p>Abstract</p> <p>Background</p> <p>There is recent evidence suggesting that rosiglitazone increases death from cardiovascular causes. We investigated the direct effect of this drug on atheroma using 3D carotid cardiovascular magnetic resonance.</p> <p>Results</p> <p>A randomized, placebo-controlled, double-blind study was performed to evaluate the effect of rosiglitazone treatment on carotid atherosclerosis in subjects with type 2 diabetes and coexisting vascular disease or hypertension. The primary endpoint of the study was the change from baseline to 52 weeks of carotid arterial wall volume, reflecting plaque burden, as measured by carotid cardiovascular magnetic resonance. Rosiglitazone or placebo was allocated to 28 and 29 patients respectively. Patients were managed to have equivalent glycemic control over the study period, but in fact the rosiglitazone group lowered their HbA1c by 0.88% relative to placebo (P < 0.001). Most patients received a statin or fibrate as lipid control medication (rosiglitazone 78%, controls 83%). Data are presented as mean ± SD. At baseline, the carotid arterial wall volume in the placebo group was 1146 ± 550 mm³and in the rosiglitazone group was 1354 ± 532 mm³. After 52 weeks, the respective volumes were 1134 ± 523 mm³and 1348 ± 531 mm³. These changes (-12.1 mm³and -5.7 mm³in the placebo and rosiglitazone groups, respectively) were not statistically significant between groups (P = 0.57).</p> <p>Conclusion</p> <p>Treatment with rosiglitazone over 1 year had no effect on progression of carotid atheroma in patients with type 2 diabetes mellitus compared to placebo.</p

Do Low Preoperative Vitamin D Levels Reduce the Accuracy of Quick Parathyroid Hormone in Predicting Postthyroidectomy Hypocalcemia?

BACKGROUND: Although some studies have suggested that low preoperative 25-hydroxyvitamin D (25-OHD) levels may increase the risk of hypocalcemia and decrease the accuracy of single quick parathyroid hormone in predicting hypocalcemia after total thyroidectomy, the literature remains scarce and inconsistent. Our study aimed to address these issues. METHODS: Of the 281 consecutive patients who underwent a total/completion total thyroidectomy, 244 (86.8 %) did not require any oral calcium and/or calcitriol supplements (group 1), while 37 (13.2 %) did (group 2) at hospital discharge. 25-OHD level was checked 1 day before surgery, and postoperative quick parathyroid hormone (PTH) was checked at skin closure (PTH-SC). Postoperative serum calcium was checked regularly. Hypocalcemia was defined by the presence of symptoms or adjusted calcium of <1.90 mmol/L. Significant factors for hypocalcemia were determined by univariate and multivariate analyses. The accuracy of PTH-SC in predicting hypocalcemia was measured by area under a receiver operating characteristic curve (AUC), and the AUC of PTH-SC was compared between patients with preoperative 25-OHD <15 and ≥15 ng/mL via bootstrapping. RESULTS: Preoperative 25-OHD level was not significantly different between groups 1 and 2 (13.1 vs. 12.5 ng/mL, p = 0.175). After adjusting for other significant factors, PTH-SC (odds ratio 2.49, 95 % confidence interval 1.52–4.07, p < 0.001) and parathyroid autotransplantation (odds ratio 3.23, 95 % confidence interval 1.22–8.60, p = 0.019) were the two independent factors for hypocalcemia. The AUC of PTH-SC was similar between those with 25-OHD <15 and ≥15 ng/mL (0.880 vs. 0.850, p = 0.61) CONCLUSIONS: Low 25-OHD was not a significant factor for hypocalcemia and did not lower the accuracy of quick PTH in predicting postthyroidectomy hypocalcemia

Anion-Dependent Construction of Two Hexanuclear 3D-4F Complexes with a Flexible Schiff Base Ligand

Two hexanuclear 3d-4f Ni-Eu and Cu-Eu complexes [Eu4Ni2L2(OAc)(12)(EtOH)(2)] (1) and [Eu4Cu2L2(OAc)(12)]center dot 2H(2)O (2) are reported which are formed from the salen type Schiff-base ligand H2L (H2L = N,N'-bis(3-methoxysalicylidene)butane-1,4-diamine). In both complexes, four Eu3+ cations are bridged by eight OAc- groups and the chain is terminated at each end by two ML (M = Ni and Cu) units. The structures of 1 and 2 were determined by single crystal X-ray crystallographic studies and the luminescence properties of the free ligand and metal complexes in solution were measured.HHMI Undergraduate Science Education Award 52005907National Science Foundation CHE-0629136, CHE-0741973, CHE-0847763Welch Foundation F-1631, F-816Hong Kong Baptist University FRG/06-07/II-16Hong Kong Research Grants Council HKBU 202407Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)Open Foundation of Jiangsu Province Key Laboratory of Fine Petrochemical Technology KF1005UT-CNM and UT-AustinChemistr

Insights into the biodegradation of PHA/wood composites: micro- and macroscopic changes

This study presents a comprehensive analysis of the microscopic and macroscopic changes during the biodegradation of composites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and wood flour (WF) in soil, to provide insights into the biodegradability of this emerging material. Composite samples with different wood contents (0, 20 and 50 wt%) were buried in soil at a field trial site in a subtropical region of Australia, alongside polylactic acid (PLA) and polyethylene (PE) based wood composites as reference. The degradation rate of the PHBV/WF composites increased with wood content, with weight loss after 12 months being five times greater for PHBV/50 wt% WF than for neat PHBV plaques under identical conditions. The mechanical properties of neat PHBV were retained after 12 months of soil burial. However, PHBV/50 wt% WF lost its mechanical integrity after 12 months, despite only a 13% loss in weight. PLA and PE composites by contrast showed only slight decreases in mechanical properties, which could be associated with moisture induced degradation at the surface only. It is proposed, with evidence from optical microscopy, that for the PHBV-based samples, localised stress loosened the interface, allowing channels for the bacteria and fungi to access PHBV in the bulk of the matrix for local enzymatic biodegradation. With this network of interconnecting pores and cracks, crack propagation and mechanical failure would readily result from an applied stress. Overall, although the erosion rate for the exposed PHBV surfaces in the different samples could be similar, the accessible surface area in PHBV/50 wt% WF composites is significantly larger following local biodegradation and subsequent void formation than for neat PHBV and thus delivers a higher biodegradation rate

Insights into the biodegradation of PHA/wood composites: micro- and macroscopic changes

This study presents a comprehensive analysis of the microscopic and macroscopic changes during the biodegradation of composites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and wood flour (WF) in soil, to provide insights into the biodegradability of this emerging material. Composite samples with different wood contents (0, 20 and 50 wt%) were buried in soil at a field trial site in a subtropical region of Australia, alongside polylactic acid (PLA) and polyethylene (PE) based wood composites as reference. The degradation rate of the PHBV/WF composites increased with wood content, with weight loss after 12 months being five times greater for PHBV/50 wt% WF than for neat PHBV plaques under identical conditions. The mechanical properties of neat PHBV were retained after 12 months of soil burial. However, PHBV/50 wt% WF lost its mechanical integrity after 12 months, despite only a 13% loss in weight. PLA and PE composites by contrast showed only slight decreases in mechanical properties, which could be associated with moisture induced degradation at the surface only. It is proposed, with evidence from optical microscopy, that for the PHBV-based samples, localised stress loosened the interface, allowing channels for the bacteria and fungi to access PHBV in the bulk of the matrix for local enzymatic biodegradation. With this network of interconnecting pores and cracks, crack propagation and mechanical failure would readily result from an applied stress. Overall, although the erosion rate for the exposed PHBV surfaces in the different samples could be similar, the accessible surface area in PHBV/50 wt% WF composites is significantly larger following local biodegradation and subsequent void formation than for neat PHBV and thus delivers a higher biodegradation rate