• Canada

1. The length of muscle fibres in the medial gastrocnemius (MG) muscle of the anaesthetized cat was measured using ultrasound techniques. During the course of ‘isometric’ contractions, the muscle fibres shortened by stretching the compliant tendons, until the muscle fibres could no longer produce enough force to stretch the tendons further. At optimal muscle length (Lo) the maximal shortening of muscle fibres was 28%. 2. At muscle lengths much longer than Lo, ‘isometric’ contractions produced a slow shortening of the muscle fibres as the tendons were stretched and this resulted in a slow rise in tension. This phenomenon, usually referred to as ‘creep’, is due to low power at long muscle fibre length. This study shows that the series compliance present in the tendons is the major contributor to ‘creep’ in the cat MG muscle. As the tendons stretched during the course of the contraction, the average sarcomere length became shorter providing greater filament overlap and increasing power. 3. Slow to medium speed stretches applied shortly after the onset of contraction, as occurs in cat MG during walking and trotting, were entirely taken up in the tendons and the muscle fibres actually shortened throughout the imposed muscle stretch. 4. When early stretches were applied at muscle lengths longer than Lo, stretch of the muscle resulted in a peak force that was less than if the stretch had not been applied. This was the reverse of the situation for stretches at lengths less than Lo. When stretch was applied after attaining peak force, the force was greatly enhanced and the muscle fibres were also stretched. 5. Using the same techniques in a freely walking cat, the muscle fibres shortened by 1.0 +/‐ 0.3 mm during the stance phase of the step‐cycle when the muscle was being stretched, in 198 consecutive step‐cycles. 6. The tendons act as a mechanical buffer to protect muscle fibres from damage during eccentric contractions. 7. Since stretches of the MG muscle are not faithfully imposed on the muscle fibres, studies of muscle spindle function during locomotion need to take into consideration these effects of tendon compliance. The dominant view, when the foot lands on the ground during normal locomotion, is that muscle spindles are stretched along with the muscle resulting in reflex enhancement of contractile force. This study shows that the muscle fibres do not stretch under these circumstances, except at high speeds of locomotion when the stretch rate is also high.

The inclusion of able-bodied athletes within disability sport, a phenomenon known as reverse integration, has sparked significant debate within adapted physical activity. Although researchers and practitioners have taken up positions for or against reverse integration, there is a lack of supporting research on the experiences of athletes who already play in such settings. In this study, we explore how competitive female athletes who have a disability experience reverse integration in Canadian wheelchair basketball. Athletic identity was used as the initial conceptual framework to guide semistructured interviews with nine participants. The results suggest that participation in this context contributed to positive athletic identities. Interviews also pointed to the unexpected theme of “what’s the difference?” that this sporting context provided a space for the questioning and creative negotiation of the categories of disability and able-bodiedness. Methodologically, this paper also explores the possibilities and challenges of inter- worldview and insider-outsider research collaboration.

Under the trend of antibiotic resistance of H. pylori leading to the decrease of eradication rate, the development of a vaccine is the best choice to fight against H. pylori. In this study, we attempted to reduce the amounts of required antigens by using three different parenteral routes of immunization and an adjuvant cGAMP (cyclic guanosine monophosphate-adenosine monophosphate) to enhance the immunogenicity of the vaccine candidate. The immune protection and post-challenge immune responses were assessed and compared in mice immunized with recombinant Helicobacter pylori urease A, urease B, and neutrophil-activating protein adjuvanted with cGAMP. The gastric mucosal colonization by H. pylori was significantly reduced in mice immunized by intranasal and, to a less degree, subcutaneous route, but not by intramuscular route. All immunized mice, regardless of the route of immunization, displayed significant, but comparable, increases in antigen-specific serum IgG and mucosal IgA responses 5 weeks post-challenge. The magnitude of the vaccine-induced protection appeared to be associated with the level of antigen-specific Th1 and particularly Th17 responses, as IL-17 responses were only detected in intranasally immunized mice. Taken together, we explored and confirmed the possibility of using a novel adjuvant (cGAMP) to induce significant protective immunity with 10% of oral vaccine antigen dosage through parenteral immunization, especially intranasal immunization. This may provide an alternative approach to oral immunization for the development of effective H. pylori vaccines.

The paper focuses on improving the recent plug-and-play patch rescaling module (PRM) based approaches for crowd counting. In order to make full use of the PRM potential and obtain more reliable and accurate results for challenging images with crowd-variation, large perspective, extreme occlusions, and cluttered background regions, we propose a new PRM based multi-resolution and multi-task crowd counting network by exploiting the PRM module with more effectiveness and potency. The proposed model consists of three deep-layered branches with each branch generating feature maps of different resolutions. These branches perform a feature-level fusion across each other to build the vital collective knowledge to be used for the final crowd estimate. Additionally, early-stage feature maps undergo visual attention to strengthen the later-stage channels understanding of the foreground regions. The integration of these deep branches with the PRM module and the early-attended blocks proves to be more effective than the original PRM based schemes through extensive numerical and visual evaluations on four benchmark datasets. The proposed approach yields a significant improvement by a margin of 12.6% in terms of the RMSE evaluation criterion. It also outperforms state-of-the-art methods in cross-dataset evaluations.

AbstractIn this study, the 3D printability of a series of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/poly(lactic acid) (PLA) blends were investigated using fused filament fabrication (FFF). The studied blends suffered from poor 3D printability due to differences in compatibility and low thermal resistance. These shortcomings were addressed by incorporating a functionalized styrene-acrylate copolymer with oxirane moieties as a chain extender (CE). To enhance mechanical properties, the synergistic effect of 3D printing parameters such as printing temperature and speed, layer thickness and bed temperature were explored. Rheological analysis showed improvement in the 3D printability of PHBV:PLA:CE blend by allowing a higher printing temperature (220 °C) and sufficient printing speed (45 mm s−1). The surface morphology of fractured tensile specimens showed good bonding between layers when a bed temperature of 60 °C was used and a layer thickness of 0.25 mm was designed. The optimized printing samples shown higher storage modulus and strength, resulting in stiffer and stronger parts. The crystallinity, morphology and performance of the 3D printed products were correlated to share key methods to improve the 3D printability of PHBV:PLA based blends which may be implemented in other biopolymer blends, and further highlight how process parameters enhance the mechanical performance of 3D printed products.

ABSTRACT Objective: Stroke guideline compliance of rural Canadian prehospital emergency medical services (EMS) care in acute stroke is unknown. In this quality assurance study, we sought to compare rural and urban care by prehospital EMS evaluation/management indicators from patients assessed at an urban Canadian stroke center.Materials and Methods: One hundred adult patients were randomly selected from the stroke registry. Patients were transported through Rural EMS bypass protocols or urban EMS protocols (both bypass and direct) to our stroke center between January and December 2013. Patients were excluded if they were first evaluated at any other health center. Prehospital care was assessed using ten indicators for EMS evaluation/management, as recommended by acute stroke guidelines. Results: Compliance with acute stroke EMS evaluation/management indicators were statistically similar for both groups, except administrating a prehospital diagnostic tool (rural 31.8 vs. urban 70.3%; P = 0.002). Unlike urban EMS, rural EMS did not routinely document scene time. Conclusion: Rural EMS responders' compliance to prehospital stroke evaluation/management was similar to urban EMS responders. Growth areas for both groups may be with prehospital stroke diagnostic tool utilization, whereas rural EMS responders may also improve with scene time documentation.

We have analyzed the effects of several natural compounds related to avarols and avarones on the catalytic functions of human immunodeficiency virus type 1 (HIV‐1) reverse transcriptase (RT). The most potent substances, designated as avarone A,B and E and avarol F, inhibited indiscriminately the enzymatic activities of HIV‐1 RT, namely the RNA‐dependent and DNA‐dependent DNA polymerase as well as the ribonuclease H. The inhibition of the DNA polymerase activity was found to be non‐competitive with respect to either the template‐primer or the deoxynucleotide‐triphosphate. These studies suggest that the hydroxyl group at the ortho position to the carbonyl group at the quinone ring is involved in blocking the RT activity. The identification of the active site of the inhibitors will hopefully lead to the rational design of new potent anti‐HIV drugs.