scholarly journals INVESTIGATION OF RECOVERY STRESS IN HIGHLY ORIENTED FIBER OF UHMWPE

2016 ◽  
Vol 4 (№ 12 2016) ◽  
Author(s):  
A.V. Maksimkin ◽  
K.S. Mostovaya ◽  
S.D. Kaloshkin ◽  
M.Yu. Zadorozhnyy
Keyword(s):  
Recovery Stress ◽  
Oriented Fiber

scholarly journals Recovery-Stress Response of Blood-Based Biomarkers

2021 ◽  
Vol 18 (11) ◽  
pp. 5776
Author(s):  
Sebastian Hacker ◽  
Thomas Reichel ◽  
Anne Hecksteden ◽  
Christopher Weyh ◽  
Kristina Gebhardt ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Tissue Repair ◽  
Elite Athletes ◽  
Venous Blood ◽  
Soccer Players ◽  
Recovery Stress ◽  
Blood Samples ◽  
Time Points ◽  
S100 Calcium Binding Protein ◽  
Stress States

The purpose of this study was to investigate blood-based biomarkers and their regulation with regard to different recovery-stress states. A total of 35 male elite athletes (13 badminton, 22 soccer players) were recruited, and two venous blood samples were taken: one in a ‘recovered’ state (REC) after a minimum of one-day rest from exercise and another one in a ‘non-recovered’ state (NOR) after a habitual loading microcycle. Overall, 23 blood-based biomarkers of different physiologic domains, which address inflammation, muscle damage, and tissue repair, were analyzed by Luminex assays. Across all athletes, only creatine kinase (CK), interleukin (IL-) 6, and IL-17A showed higher concentrations at NOR compared to REC time points. In badminton players, higher levels of CK and IL-17A at NOR were found. In contrast, a higher value for S100 calcium-binding protein A8 (S100A8) at REC was found in badminton players. Similar differences were found for BDNF in soccer players. Soccer players also showed increased levels of CK, and IL-6 at NOR compared to REC state. Several molecular markers were shown to be responsive to differing recovery-stress states, but their suitability as biomarkers in training must be further validated.

scholarly journals Behavior of NiTiNb SMA wires under recovery stress or prestressing

2012 ◽  
Vol 7 (1) ◽  
Author(s):  
Eunsoo Choi ◽  
Tae-hyun Nam ◽  
Young-Soo Chung ◽  
Yeon-Wook Kim ◽  
Seung-yong Lee
Keyword(s):  
Recovery Stress

Wear Mechanism of Unidirectionally Oriented Fiber-Reinforced Plastics

1977 ◽  
Vol 99 (4) ◽  
pp. 401-407 ◽  
Author(s):  
T. Tsukizoe ◽  
N. Ohmae
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibers ◽  
Wear Behavior ◽  
High Modulus ◽  
Fiber Reinforced ◽  
Reinforced Plastics ◽  
Sliding Direction ◽  
Oriented Fiber ◽  
Fiber Reinforcements ◽  
Fiber Reinforced Plastics

Wear between unidirectionally oriented fiber-reinforced-plastics and mild steel has been investigated. The wear behavior was found to be greatly influenced by the sliding direction, the mechanical properties of fiber-reinforced-plastics and by the tribological properties of fiber-reinforcements or matrices. A summarization of wear-resistance of seven different kinds of fiber-reinforced-plastics signified that the epoxy resin reinforced with high-modulus carbon fibers was the best wear-resistant fiber-reinforced-plastics.

Recovery-Stress States of Professional Ballet Dancers During Different Phases of a Ballet Season

2021 ◽  
Author(s):  
Jana S. De Wet ◽  
Eileen Africa ◽  
Ranel Venter
Keyword(s):  
Mixed Model ◽  
High Stress ◽  
Recovery Stress ◽  
Total Recovery ◽  
Ballet Dancers ◽  
Training Adaptations ◽  
Stress States ◽  
Classical Ballet ◽  
And Performance ◽  
Negative Training

Ballet dancers are exposed to chronic high training and performance demands that are associated with overtraining syndrome and injury. Balancing high training loads with recovery to reduce the risk of negative training adaptations is critical. Moreover, the recovery-stress states of professional ballet dancers during training phases of a season are largely unknown. Professional dancers (n = 27) from one classical ballet company in South Africa were monitored for two 8-week phases of a ballet season. A recovery-stress questionnaire for Athletes (RESTQ-76 Sport) was completed weekly during the rehearsal phase (P1) and the performance phase (P2), which took place at the start and the end of the ballet season, respectively. Comparisons were calculated between phases, sexes, and levels of performance with a mixed-model ANOVA and between demographic variables with a one-way ANOVA. The performance phase was signified by lower total recovery (TR, p < 0.01) and higher total stress (TS, p < 0.01) for the group. Female dancers had significantly lower recovery scores than male dancers during P2 (p < 0.01). No differences between levels of performance were found. Subscales previously associated with overreaching and injury were identified in certain groups during P2. In conclusion, P2 was a critical period where dancers, especially females, experienced high stress and low recovery. This could increase the risk for injury and negative training adaptations.

scholarly journals Oxidative stress, inflammation, psychological status, and severity of respiratory infections are negatively affected during the pre-contest period in amateur bodybuilders

2019 ◽  
Vol 44 (5) ◽  
pp. 468-476 ◽  
Author(s):  
Wilson Max Almeida Monteiro de Moraes ◽  
Felipe Carmo de Moura ◽  
Thamires Cristina da Costa Moraes ◽  
Luís Gustavo Oliveira de Sousa ◽  
Thiago dos Santos Rosa ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Respiratory Infections ◽  
Mood States ◽  
Fat Free Mass ◽  
Psychological Status ◽  
Protein Carbonyls ◽  
Positive Energy ◽  
Recovery Stress ◽  
Upper Respiratory ◽  
Almost All

We examined whether off-season (OffS) and pre-contest (PreC) periods affect blood oxidative stress, inflammatory, immunological, and psychological markers in 20 bodybuilders. The athletes recorded their food intake (3-day record), physical activities, mood states (Profile of Mood States, POMS), recovery-stress (Recovery–Stress Questionnaire for Athletes, RESTQ-Sport), and upper respiratory symptoms (Wisconsin Upper Respiratory Symptom Survey, WURSS-21), and blood was obtained for biochemical analysis. Almost all athletes were in positive energy balance during OffS, while bodybuilders presented markedly restricted energy intake (∼45%) leading to loss of weight (–9%) and fat mass (–45%) with preservation of fat-free mass in PreC. Protein intake was high during both periods, while lipid and carbohydrate intakes were reduced ∼50% in PreC. Almost all athletes consumed 100% of the Recommended Dietary Allowance (RDA) for micronutrients in OffS, while 45% and 75% of the athletes had intakes below the RDA for vitamins A and E in PreC. Oxidative damage to lipids (thiobarbituric acid reactive substances, TBARS), protein carbonyls, and the TBARS/total antioxidant capacity ratio increased in PreC (32%, 27%, 60%), as did plasma tumor necrosis factor α (4-fold) and WURSS-21 scores (25%). There were no significant changes in serum catalase, glutathione reductase, and superoxide dismutase activities nor in interleukin 1β and immunoglobulins. In PreC, POMS showed negative changes in vigor (–20%), fatigue (23%), and total mood disturbance (35%), and RESTQ-Sport showed alterations for general and sport stress (34% and 50%, respectively) and sport recovery (–23%). Thus, PreC negatively affects nutrient intake, which may worsen oxidative stress, inflammation, psychological status, and the severity of respiratory infections in bodybuilders.

Novel Behavior in Smart Polymeric Materials: Stress Memory and its Potential Applications

2016 ◽  
Vol 97 ◽  
pp. 93-99
Author(s):  
Jin Lian Hu ◽  
Harishkumar Narayana
Keyword(s):  
Magnetic Field ◽  
Shape Memory ◽  
Smart Materials ◽  
Shape Memory Polymers ◽  
Polymeric Materials ◽  
External Stimulus ◽  
Artificial Muscles ◽  
Recovery Stress ◽  
Stress Memory ◽  
Potential Applications

Materials, structures and systems, responsive to an external stimulus are smart and adaptive to our human demands. Among smart materials, polymers with shape memory effect are at the forefront of research leading to comprehensive publications and wide applications. In this paper, we extend the concept of shape memory polymers to stress memory ones, which have been discovered recently. Like shape memory, stress memory represents a phenomenon where the stress in a polymer can be programmed, stored and retrieved reversibly with an external stimulus such as temperature and magnetic field. Stress memory may be mistaken as the recovery stress which was studied quite broadly. Our further investigation also reveals that stress memory is quite different from recovery stress containing multi-components including elastic and viscoelastic forces in addition to possible memory stress. Stress memory could be used into applications such as sensors, pressure garments, massage devices, electronic skins and artificial muscles. The current revelation of stress memory potentials is emanated from an authentic application of memory fibres, films, and foams in the smart compression devices for the management of chronic and therapeutic disorders.

scholarly journals Feasibility of Crosslinked Acrylic Shape Memory Polymer for a Thrombectomy Device

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Andrea D. Muschenborn ◽  
Keith Hearon ◽  
Brent L. Volk ◽  
Jordan W. Conway ◽  
Duncan J. Maitland
Keyword(s):  
Crosslink Density ◽  
Blood Clot ◽  
Shape Memory Polymer ◽  
Thermomechanical Properties ◽  
Recovery Stress ◽  
Element Analysis ◽  
Clot Removal ◽  
Acrylic Copolymers ◽  
Thrombectomy Device ◽  
And Performance

Purpose. To evaluate the feasibility of utilizing a system of SMP acrylates for a thrombectomy device by determining an optimal crosslink density that provides both adequate recovery stress for blood clot removal and sufficient strain capacity to enable catheter delivery. Methods. Four thermoset acrylic copolymers containing benzyl methacrylate (BzMA) and bisphenol A ethoxylate diacrylate (Mn∼512, BPA) were designed with differing thermomechanical properties. Finite element analysis (FEA) was performed to ensure that the materials were able to undergo the strains imposed by crimping, and fabricated devices were subjected to force-monitored crimping, constrained recovery, and bench-top thrombectomy. Results. Devices with 25 and 35 mole% BPA exhibited the highest recovery stress and the highest brittle response as they broke upon constrained recovery. On the contrary, the 15 mole% BPA devices endured all testing and their recovery stress (5 kPa) enabled successful bench-top thrombectomy in 2/3 times, compared to 0/3 for the devices with the lowest BPA content. Conclusion. While the 15 mole% BPA devices provided the best trade-off between device integrity and performance, other SMP systems that offer recovery stresses above 5 kPa without increasing brittleness to the point of causing device failure would be more suitable for this application.

Phase Transformation and Recovery Stress of Ni47Ti44Nb9 Alloy During Constrained Heating and Cooling

2019 ◽  
Vol 51 (1) ◽  
pp. 390-399 ◽  
Author(s):  
Q. C. Fan ◽  
M. Y. Sun ◽  
Y. Y. Wang ◽  
K. H. Sun ◽  
X. D. Cao ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Recovery Stress ◽  
Heating And Cooling
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