University evaluations often reflect an individual’s ability to memorize and recall lecture material during exams. Consequently, the ability to effectively encode, store, and later retrieve information is an integral part of learning and academic success. Notably, students who are more physically active tend to have better academic performance. The neurobiology of stress is a strong candidate for the mechanism underlying this exercise-cognition interaction. Given that exercise is a physical stressor, it is hypothesized that exercise-induced adrenocortical activations increase cortisol levels. Critically, cortisol increases memory consolidation for newly learned information. One hundred twenty-eight young adults (36 males; age: M±SD =19.47±1.55 years) viewed a video lecture before exercise (n = 41), after exercise (n = 42), or after rest (n = 45). The exercise was high intensity interval training on a cycle ergometer and memory for the lecture material was assessed using a multiple-choice quiz conducted 14 minutes and 48 hours after the lecture. There was a significant positive correlation between aerobic fitness and grade point average [r(95) = 0.22, p < .05], immediate recall [r(100) = 0.39, p < .001], and delayed recall [r(98) = 0.28, p < .01]. A mixed model ANOVA found a significant main effect of group on comprehension of the lecture material, F(2, 96) = 3.34, p < .05, revealing greater memory benefits at both 14 minutes and 48 hour delays for those who exercised compared to those who did not exercise; however, pairwise comparisons found this effect specific to the exercise post group. There was also a main effect of group on cortisol levels, F(2, 107) = 3.97, p < .05; however, only the exercise prior group exhibited significantly greater levels than the control group. Thus cortisol levels collected during the experimental session did not clearly differentiate the exercise conditions or reflect the observed memory benefits for the exercise post group. This may have resulted from the gradual increase in cortisol following exercise that had time to increase when exercise was completed at the beginning of the exercise session (exercise prior) rather than at the end (exercise post). Overall, this study suggests that both physical fitness and an acute bout of aerobic exercise are associated with academic and memory performance. More research is needed to understand the mechanism. / Thesis / Master of Science (MSc)

Small-scale anaerobic digesters, known as biogas plants, were applied as an optimal livestock waste treatment as well as biogas supply for cooking and lighting demand for small-scale farmers in Vietnam. Although the biogas technology was introduced for nearly 30 years, the number of the constructed biogas plants is still limited. The current development of biogas plants is far below the real demand on livestock waste treatment that has increased significantly. This paper gives a comprehensive overview on the biogas plant development in Vietnam and attempts to address the challenges and discuss appropriate solutions for the further biogas development. / Mô hình lên men yếm khí quy mô nhỏ (được biết với tên hầm ủ khí sinh học) đã được ứng dụng hiệu quả trong xử lý chất thải chăn nuôi cũng như cung cấp nguồn nhiên liệu phục vụ nhu cầu nấu ăn và thắp sáng cho các hộ chăn nuôi nhỏ ở Việt Nam. Mặc dù đã hiện diện gần 30 năm, nhưng số lượng hầm ủ khí sinh học vẫn còn hạn chế. Sự gia tăng số lượng hầm ủ khí sinh học chưa theo kịp với nhu cầu về xử lý chất thải chăn nuôi đang ngày càng gia tăng. Bài báo trình bày các chặng đường phát triển của hầm ủ khí sinh học tại Việt Nam, ghi nhận các thách thức trong việc nhân rộng hầm ủ khí sinh học trong thực tế và thảo luận một số giải pháp để phát triển công nghệ khí sinh học.

Myotonic dystrophy type 1 (DM1) is an autosomal dominant and progressive neuromuscular disorder caused by the CTG trinucleotide repeat expansion in the 3’ untranslated region of the DMPK gene. Clinical manifestations include extensive atrophy of skeletal muscle (SkM) concomitant with muscle weakness, that develops in a distal to proximal fashion. Central to muscle plasticity is the satellite cell (SC), a muscle specific stem cell that, upon activation, facilitates muscle repair and regeneration. To date, SCs have yet to be elucidated in DM1; therefore, the aim of the present study was to extensively characterize the PAX7+ SC population, along with other indices of muscle quality in SkM. DM1 patients (6 women, 5 men) performed stationary cycling 3 times per week for 12wks, with biopsies taken from the Vastus lateralis pre- (PRE) and post-endurance exercise intervention (POST). Age-matched, healthy controls (CTRL) were used for comparison of baseline measures. Type 1 and 2 myofiber-specific PAX7+ cells were significantly greater in DM1 patients (PRE), in comparison to CTRL (2.24- and 1.84-fold, respectively), with type 2 SC content further increasing following training (p<0.05). In addition, protein expression of myogenic regulatory factors PAX7 and myogenin were significantly higher in DM1 compared to CTRL, with no training effects observed. Both immunohistochemical and immunoblotting analysis showed that activated MYOD+/PAX7+ cells did not significantly differ in DM1 vs. CTRL. FISH- IF analysis of CUG repeats show that 30% of SCs in DM1 were positive for these inclusions. Muscle capillarization was significantly lower in type 2 fibers in DM1 vs CTRL, which was fully rescued with training (p<0.05). At baseline, DM1 muscle showed the presence of de novo and fat infiltrated fibres, as well as fibrosis, that were relatively non-existent in the CTRL. In vitro results show patient-derived myoblasts exhibit a proliferation defect. Furthermore, myoblasts showed impairments in both glycolysis and mitochondrial respiration, with the latter being completely normalized to CTRL in myotubes. Our novel findings display an increased, albeit non-functional, SC pool in DM1 SkM indicated by disturbances in the myogenic program and overall poor muscle quality. We show that both SCs and SkM remain responsive to exercise training, suggesting therapeutic potential. We also suggest that mitochondrial dysfunction may underpin these impairments in the myogenic program. / Thesis / Master of Science (MSc) / Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy in adults worldwide affecting 1:8000 individuals, with certain areas in northeastern Quebec having a higher prevalence of 1:600 individuals. DM1 is caused by an autosomal dominant genetic mutation that leads to muscle weakness, respiratory insufficiency, cataracts and cardiac conduction block, ultimately resulting in poor quality of life and shortened lifespan. Preliminary evidence suggests that the maintenance of muscle health can greatly improve quality of life and life-span of these individuals, making an in-depth research focus on this therapeutic intervention extremely important. Optimal muscle health is maintained by the functionality of muscle stem cells, that aid in muscle repair and facilitate adaptations in muscle following exercise interventions. These cells are shown to be dys- or non-functional in various muscular dystrophies which coincide with the observation of poor muscle health. Therefore, the aim of this study was to examine the number and functionality of muscle stem cells, and physiological factors of muscle health in DM1. In addition, we also aimed to explore whether exercise has therapeutic potential to alleviate poor muscle quality in DM1. In general, we found that DM1 patients have a higher proportion of muscle stem cells; however, they are inherently dysfunctional but did respond to exercise. Consistent with the latter observation, we found poor muscle quality metrics in DM1 patients, with aerobic training leading to improvements in muscle health. Altogether, our results provide in-depth analysis that underscores muscle dysfunction observed in DM1 and the benefits of exercise interventions.

A bifidobacteria mix (nine strains) was evaluated for its effect on the growth and survival of Escherichia coli O157:H7 (ATCC 43890) in 11% NFDM and MRS broth under the optimum growth conditions for E. coli O157:H7 growth (37¡ãC, aerobic). Preliminary experiments were conducted to obtain the growth curves of the 9 strains of bifidobacteria and E. coli O157:H7 and confirm the inhibitory effect of acidity on E. coli O157:H7 (pH of media adjusted to 3.8). Acidapted E. coli O157:H7 showed no difference in resistance toward bifidobacteria (P>0.05) when compared to the non-acid adapted one. Escherichia coli O157:H7 did not survive in the supernatant of the bifodbacteria mix collected after incubation (37¡ãC) with aerobic shaking (8 h). However, the pathogen was able to grow after the pH of the supernatant was adjusted to 6.50 (pH of fresh MRS broth). Results suggest that a high content of bifidobacteria has a strong inhibitory effect on E. coli O157:H7, in part due to the low pH. However, products from bifidobacteria may also exert inhibitory effects.

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