Search results for: muscle fatigue

Authors: Hande Burcu Deniz

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People in the U.S. spend a considerable portion of their time indoors. This makes it crucial to provide environments that support the well-being of people. Restorative environments aim to help people recover their cognitive resources that were spent due to intensive use of directed attention. Spending time in nature and taking a nap are two of the best ways to restore these resources. However, they are not possible to do most of the time. The problem is that many studies have revealed how nature and spending time in natural contexts can help boost restoration, but there are fewer studies conducted to understand how cognitive resources can be restored in interior settings. This study aims to explore the answer to this question: which qualities of interiors increase the restorativeness of an interior setting and how do they mediate restorativeness of an interior. To do this, a phenomenological qualitative study was conducted. The study was interested in the definition of attention restoration and the experiences of the phenomena. As the themes emerged, they were analyzed to match with Attention Restoration Theory components (being away, extent, fascination, compatibility) to examine how interior design elements mediate the restorativeness of an interior. The data was gathered from semi-structured interviews with international residents of Minnesota. The interviewees represent young professionals who work in Minnesota and often experience mental fatigue. Also, they have less emotional connections with places in Minnesota, which enabled data to be based on the physical qualities of a space rather than emotional connections. In the interviews, participants were asked about where they prefer to be when they experience mental fatigue. Next, they were asked to describe the physical qualities of the places they prefer to be with reasons. Four themes were derived from the analysis of interviews. The themes are in order according to their frequency. The first, and most common, the theme was “connection to outside”. The analysis showed that people need to be either physically or visually connected to recover from mental fatigue. Direct connection to nature was reported as preferable, whereas urban settings were the secondary preference along with interiors. The second theme emerged from the analysis was “the presence of the artwork,” which was experienced differently by the interviewees. The third theme was “amenities”. Interviews pointed out that people prefer to have the amenities that support desired activity during recovery from mental fatigue. The last theme was “aesthetics.” Interviewees stated that they prefer places that are pleasing to their eyes. Additionally, they could not get rid of the feeling of being worn out in places that are not well-designed. When we matched the themes with the four art components (being away, extent, fascination, compatibility), some of the interior qualities showed overlapping since they were experienced differently by the interviewees. In conclusion, this study showed that interior settings have restorative potential, and they are multidimensional in their experience.

Keywords: attention restoration, fatigue, interior design, qualitative study, restorative environments

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Authors: Shaher A. I. Shalfawi, Fredrik Hviding, Bjornar Kjellstadli

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The main purpose of this study was to measure the effect of two different strength training methods on muscle strength, muscle mass, fat mass and endurance factors. Fourteen physical education students accepted to participate in this study. The participants were then randomly divided into three groups, traditional training group (TTG), cluster training group (CTG) and control group (CG). TTG consisted of 4 participants aged ( ± SD) (22.3 ± 1.5 years), body mass (79.2 ± 15.4 kg) and height (178.3 ± 11.9 cm). CTG consisted of 5 participants aged (22.2 ± 3.5 years), body mass (81.0 ± 24.0 kg) and height (180.2 ± 12.3 cm). CG consisted of 5 participants aged (22 ± 2.8 years), body mass (77 ± 19 kg) and height (174 ± 6.7 cm). The participants underwent a hypertrophy strength training program twice a week consisting of 4 sets of 10 reps at 70% of one-repetition maximum (1RM), using barbell squat and barbell bench press for 8 weeks. The CTG performed 2 x 5 reps using 10 s recovery in between repetitions and 50 s recovery between sets, while TTG performed 4 sets of 10 reps with 90 s recovery in between sets. Pre- and post-tests were administrated to assess body composition (weight, muscle mass, and fat mass), 1RM (bench press and barbell squat) and a laboratory endurance test (Bruce Protocol). Instruments used to collect the data were Tanita BC-601 scale (Tanita, Illinois, USA), Woodway treadmill (Woodway, Wisconsin, USA) and Vyntus CPX breath-to-breath system (Jaeger, Hoechberg, Germany). Analysis was conducted at all measured variables including time to peak VO2, peak VO2, heart rate (HR) at peak VO2, respiratory exchange ratio (RER) at peak VO2, and number of breaths per minute. The results indicate an increase in 1RM performance after 8 weeks of training. The change in 1RM squat was for the TTG = 30 ± 3.8 kg, CTG = 28.6 ± 8.3 kg and CG = 10.3 ± 13.8 kg. Similarly, the change in 1RM bench press was for the TTG = 9.8 ± 2.8 kg, CTG = 7.4 ± 3.4 kg and CG = 4.4 ± 3.4 kg. The within-group analysis from the oxygen consumption measured during the incremental exercise indicated that the TTG had only a statistical significant increase in their RER from 1.16 ± 0.04 to 1.23 ± 0.05 (P < 0.05). The CTG had a statistical significant improvement in their HR at peak VO2 from 186 ± 24 to 191 ± 12 Beats Per Minute (P < 0.05) and their RER at peak VO2 from 1.11 ± 0.06 to 1.18 ±0.05 (P < 0.05). Finally, the CG had only a statistical significant increase in their RER at peak VO2 from 1.11 ± 0.07 to 1.21 ± 0.05 (P < 0.05). The between-group analysis showed no statistical differences between all groups in all the measured variables from the oxygen consumption test during the incremental exercise including changes in muscle mass, fat mass, and weight (kg). The results indicate a similar effect of hypertrophy strength training irrespective of the methods of the training used on untrained subjects. Because there were no notable changes in body-composition measures, the results suggest that the improvements in performance observed in all groups is most probably due to neuro-muscular adaptation to training.

Keywords: hypertrophy strength training, cluster set, Bruce protocol, peak VO2

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Authors: Shi-Uk Lee, Chae Young Lim

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Objective: The aim of this study was to evaluate the changes of lumbar deep muscle thickness and cross-sectional area using ultrasonography with magnetic stimulation. Methods: To evaluate the changes of lumbar deep muscle by using magnetic stimulation, 12 healthy volunteers (39.6±10.0 yrs) without low back pain during 3 months participated in this study. All the participants were checked with X-ray and electrophysiologic study to confirm that they had no problems with their back. Magnetic stimulation was done on the L5 and S1 root with figure-eight coil as previous study. To confirm the proper motor root stimulation, the surface electrode was put on the tibialis anterior (L5) and abductor hallucis muscles (S1) and the hot spots of magnetic stimulation were found with 50% of maximal magnetic stimulation and determined the stimulation threshold lowering the magnetic intensity by 5%. Ultrasonography was used to assess the changes of L5 and S1 lumbar multifidus (superficial and deep) cross-sectional area and thickness with maximal magnetic stimulation. Cross-sectional area (CSA) and thickness was evaluated with image acquisition program, ImageJ software (National Institute of Healthy, USA). Wilcoxon signed-rank was used to compare outcomes between before and after stimulations. Results: The mean minimal threshold was 29.6±3.8% of maximal stimulation intensity. With minimal magnetic stimulation, thickness of L5 and S1 deep multifidus (DM) were increased from 1.25±0.20, 1.42±0.23 cm to 1.40±0.27, 1.56±0.34 cm, respectively (P=0.005, P=0.003). CSA of L5 and S1 DM were also increased from 2.26±0.18, 1.40±0.26 cm2 to 2.37±0.18, 1.56±0.34 cm2, respectively (P=0.002, P=0.002). However, thickness of L5 and S1 superficial multifidus (SM) were not changed from 1.92±0.21, 2.04±0.20 cm to 1.91±0.33, 1.96±0.33 cm (P=0.211, P=0.199) and CSA of L5 and S1 were also not changed from 4.29±0.53, 5.48±0.32 cm2 to 4.42±0.42, 5.64±0.38 cm2. With maximal magnetic stimulation, thickness of L5, S1 of DM and SM were increased (L5 DM, 1.29±0.26, 1.46±0.27 cm, P=0.028; L5 SM, 2.01±0.42, 2.24±0.39 cm, P=0.005; S1 DM, 1.29±0.19, 1.67±0.29 P=0.002; S1 SM, 1.90±0.36, 2.30±0.36, P=0.002). CSA of L5, S1 of DM and SM were also increased (all P values were 0.002). Conclusions: Deep lumbar muscles could be stimulated with lumbar motor root magnetic stimulation. With minimal stimulation, thickness and CSA of lumbosacral deep multifidus were increased in this study. Further studies are needed to confirm whether the similar results in chronic low back pain patients are represented. Lumbar magnetic stimulation might have strengthening effect of deep lumbar muscles with no discomfort.

Keywords: magnetic stimulation, lumbar multifidus, strengthening, ultrasonography

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Authors: Wang Yuan-hao, Habtamu Ayalew, Jing Wang, Shugeng Wu, Kai Qiu, Guanghai Qi, Haijun Zhang

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N-carbamylglutamate (NCG) has emerged as a promising candidate for regulating endogenous arginine synthesis, thereby promoting desirable growth, carcass traits, and muscle development in broilers. Thus, this study aimed to investigate the effects of NCG in ovo feeding on the growth performance, growth hormones, and meat quality of Ross 308 breeder broilers. A total of 1680 embryo eggs were equally allocated into three treatment groups: non punctured control (NC), saline-injected control (SC; 100μL/egg), and N-carbamylglutamate injected group (NCG; 2 mg/egg). The treatment solution was injected into the amniotic cavity of the embryo at 17.5 days of incubation (DOI). For the subsequent 42 days of post hatch experimental sampling, a total of 360 broiler chicks with 6 replications per treatment and 15 chicks per replication were used. Chickens in the NCG group showed significantly higher (P<0.05) body weight gain (BWG) and final body weight (FBW) at both 21 and 42 days after hatch (DAH), while feed conversion efficiency (FCE) was significantly improved (P<0.05) at 42 DAH. The weight and percentage of drums at 21 DAH and the weight and percentage of breast muscle at 42 DAH were significantly higher (P<0.05) in the NCG group. In addition, insulin (INS), growth hormone (GH), and testosterone (T) levels were significantly higher (P<0.05) in the NCG groups at 21 and 42 DAH. Furthermore, triiodothyronine (T3) and tetraiodothyronine (T4) levels were significantly higher (P<0.05) in the NCG treatment group. Interestingly, meat color values were also significantly higher (P<0.05) in the NCG group at 24 hrs postmortem. Collectively, these findings show that 2 mg NCG in ovo injection improves the growth performance and meat quality of broilers; even the effects extend into the market age of the chickens.

Keywords: N-carbamylglutamate, broiler, in ovo injection, growth performance, meat quality

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Authors: Kunthida Kulprateepunya, Napat Boontiam, Bunthita Phuasa, Chatsuda Kankayant, Bantoeng Polsawat, Sumran Poontong

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Frailty is the thin line between good health and illness. The syndrome is more common in the elderly who transition from strong to weak. (Vulnerability). Fragility can prevent and promote healthy recovery before it goes into disability. This research and development aim to analyze the situation analysis of frailty of the elderly, develop a program, and evaluate the effect of a health promotion program to prevent and solve the problem of frailty among the elderly. The research consisted of 3 phases: 1) analysis of the frailty situation, 2) development of a model, 3) evaluation of the effectiveness of the model. Samples were 328, 122 elderlies using the multi-stage random sampling method. The research instrument was a frailty questionnaire use of the five symptoms, the main characteristics were muscle weakness, slow walking, low physical activity. Fatigue and unintentional weight loss, criteria frailty use more than or equal to three or more symptoms are frailty. Data were analyzed by descriptive and t-test dependent test statistics. The findings showed three parts. First, frailty in the elderly was 23.05 percentage and 56.70% pre-frailty. Second, it was development of a health promotion program to prevent and solve the problem of frailty the elderly with a combination of Nine-Square Exercise, Elastic Band Exercise, Elastic Coconut Shell. Third, evaluation of the effectiveness of the model by comparison of the elderly's get up and go test, the average time before using the program was 14.42 and after using the program was 8.57. It was statistically significant at the .05 level. In conclusion, the findings can used to develop guidelines to promote the health of the frailty elderly.

Keywords: elderly, fragile, nine-square exercise, elastic coconut shell

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Authors: Katie Jerram, Jacqui Nevols, Rebecca Howes, Hayley Richardson, Debbie Suso, Thomas Batten, Reny Mathai

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Pyomyositis is an uncommon acute purulent skeletal muscle infection, usually caused by Staphylococcus aureus, occurring either spontaneously or following local trauma. Immunocompromise is a risk factor. It presents with pyrexia, pain, and tenderness of the affected muscle, which may have a firm ‘woody’ feel. Management usually involves surgery and prolonged courses of antibiotics, but alongside these active treatments, palliation of symptoms such as pain is also a priority. A short case series of diabetic inpatients under the care of the Renal Medicine team with pyomyositis is presented, demonstrating that Hospital Palliative Care Teams may be well placed to provide symptom management advice by working jointly with the patient’s medical or surgical team. A review of the literature on the management of pain in pyomyositis is also presented, and there was no clear consensus on the best strategy. It may be that a combination of analgesics and adjuncts is the most effective strategy, perhaps combined with the holistic approach used within palliative care.

Keywords: pyomyositis, pain, palliation, analgesia

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Authors: Ming Wen, Nasim Nezamoddini

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Sophisticated numerical simulations like finite element analysis (FEA) involve a complicated process from model setup to post-processing tasks that require replication of time-consuming steps. Utilizing FEA automation program simplifies the complexity of the involved steps while minimizing human errors in analysis set up, calculations, and results processing. One of the main challenges in designing FEA automation programs is to identify user requirements and link them to possible design alternatives. This paper presents a decision-making framework to design a Python based FEA automation program for modal analysis, frequency response analysis, and random vibration fatigue (RVF) analysis procedures. Analytical hierarchy process (AHP) and technique for order preference by similarity to ideal solution (TOPSIS) are applied to evaluate design alternatives considering the feedback received from experts and program users.

Keywords: finite element analysis, FEA, random vibration fatigue, process automation, analytical hierarchy process, AHP, TOPSIS, multiple-criteria decision-making, MCDM

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Authors: Antonio Monteiro, Jorge Azevedo, Severiano Silva, Alfredo Teixeira

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The objective of this study was to compare the carcass and in vivo real-time ultrasound measurements (RTU) and their capacity to predict the composition of Serrana goats up to 40% of maturity. Twenty one females (11.1 ± 3.97 kg) and Twenty one males (15.6 ± 5.38 kg) were utilized to made in vivo measurements with a 5 MHz probe (ALOKA 500V scanner) at the 9th-10th, 10th-11th thoracic vertebrae (uT910 and uT1011, respectively), at the 1st- 2nd, 3rd-4th, and 4th-5th lumbar vertebrae (uL12, ul34 and uL45, respectively) and also at the 3rd-4th sternebrae (EEST). It was recorded the images of RTU measurements of Longissimus thoracis et lumborum muscle (LTL) depth (EM), width (LM), perimeter (PM), area (AM) and subcutaneous fat thickness (SFD) above the LTL, as well as the depth of tissues of the sternum (EEST) between the 3rd-4th sternebrae. All RTU images were analyzed using the ImageJ software. After slaughter, the carcasses were stored at 4 ºC for 24 h. After this period the carcasses were divided and the left half was entirely dissected into muscle, dissected fat (subcutaneous fat plus intermuscular fat) and bone. Prior to the dissection measurements equivalent to those obtained in vivo with RTU were recorded. Using the Statistica 5, correlation and regression analyses were performed. The prediction of carcass composition was achieved by stepwise regression procedure, with live weight and RTU measurements with and without transformation of variables to the same dimension. The RTU and carcass measurements, except for SFD measurements, showed high correlation (r > 0.60, P < 0.001). The RTU measurements and the live weight, showed ability to predict carcass composition on muscle (R2 = 0.99, P < 0.001), subcutaneous fat (R2 = 0.41, P < 0.001), intermuscular fat (R2 = 0.84, P < 0.001), dissected fat (R2 = 0.71, P < 0.001) and bone (R2 = 0.94, P < 0.001). The transformation of variables allowed a slight increase of precision, but with the increase in the number of variables, with the exception of subcutaneous fat prediction. In vivo measurements by RTU can be applied to predict kid goat carcass composition, from 5 measurements of RTU and the live weight.

Keywords: carcass, goats, real time, ultrasound

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Authors: Liudmila Garzanova, Lidia Ananyeva, Olga Koneva, Olga Ovsyannikova, Oxana Desinova, Mayya Starovoytova, Rushana Shayahmetova, Anna Khelkovskaya-Sergeeva

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Objectives. There is very few data on changes of the musculoskeletal manifestations (artritis, arthralgia, muscle weakness, etc.) in systemic sclerosis (SSc) on rituximab (RTX) therapy. The aim of our study was to assess the severity of the musculoskeletal involvement in SSc patients (pts) and its changes during RTX therapy. Methods. Our study included 103 pts with SSc. The mean followup period was 12.6±10.7 months. The mean age was 47±12.9 years, female-87 pts (84%), the diffuse cutaneous subset of the disease had 55 pts (53%). The mean disease duration was 6.2±5.5 years. All pts had interstitial lung disease (ILD) and were positive for ANA, 67% of them were positive for antitopoisomerase-1. All patients received prednisolone at a dose of 11.3±4.5 mg/day, immunosuppressants at inclusion received 47% of them. Pts received RTX due to the ineffectiveness of previous therapy for ILD. The cumulative mean dose of RTX was 1.7±0.6 grams. Arthritis was observed in 22 pts (21%), arthralgias in 47 pts (46%). Muscle weakness was observed in 17 pts (17%). Tendon friction rubs was established in 7 pts (7%). The results at baseline and at the end of the follow up are presented in the form of mean values. Results. There was an improvement of all outcome parameters and musculoskeletal manifestations on RTX therapy. There was a decrease in the number of pts with arthritis from 22 (21%) to 10 (9%), a decrease in the number of pts with arthralgias from 47 (46%) to 31 (30%). The number of pts with muscle weakness decreased from 17 (17%) to 7 (7%). The number of pts with tendon friction rubs decreased from 7 (7%) to 3 (3%). The creatine phosphokinase decreased from 365.5±186 to 70.8±50.4 (p=0.00006). The C-reactive protein (CRP) decreased from 23.2±31.3 to 8.62±7.4 (p=0.001). The dose of prednisolone was reduced from 11.3±4.5 to 9.8±3.5 mg/day (p=0.0004). Conclusion. In our study, musculoskeletal involvement was detected in almost half of the patients with SSc-ILD. There was an improvement of musculoskeletal manifestations despite a small cumulative dose of RTX. We also managed to reduce the dose of glucocorticosteroids. The improvement of musculoskeletal manifestations was accompanied by a decrease in laboratory parameters - creatine phosphokinase and CRP. RTX is effective option for treatment of musculoskeletal manifestations in SSc.

Keywords: arthritis, musculoskeletal involvement, systemic sclerosis, rituximab

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Authors: Saif Al-Qaisi, Alif Saba

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Normalization of electromyography (EMG) data in ergonomics research is a prerequisite for interpreting the data. Normalizing accounts for variability in the data due to differences in participants’ physical characteristics, electrode placement protocols, time of day, and other nuisance factors. Typically, normalized data is reported as a percentage of the muscle’s isometric maximum voluntary contraction (%MVC). Various MVC techniques have been recommended in the literature for normalizing EMG activity of back muscles. This research tests and compares the recommended MVC techniques in the literature for three back muscles commonly used in ergonomics research, which are the lumbar erector spinae (LES), latissimus dorsi (LD), and thoracic erector spinae (TES). Six healthy males from a university population participated in this research. Five different MVC exercises were compared for each muscle using the Tringo wireless EMG system (Delsys Inc.). Since the LES and TES share similar functions in controlling trunk movements, their MVC exercises were the same, which included trunk extension at -60°, trunk extension at 0°, trunk extension while standing, hip extension, and the arch test. The MVC exercises identified in the literature for the LD were chest-supported shoulder extension, prone shoulder extension, lat-pull down, internal shoulder rotation, and abducted shoulder flexion. The maximum EMG signal was recorded during each MVC trial, and then the averages were computed across participants. A one-way analysis of variance (ANOVA) was utilized to determine the effect of MVC technique on muscle activity. Post-hoc analyses were performed using the Tukey test. The MVC technique effect was statistically significant for each of the muscles (p < 0.05); however, a larger sample of participants was needed to detect significant differences in the Tukey tests. The arch test was associated with the highest EMG average at the LES, and also it resulted in the maximum EMG activity more often than the other techniques (three out of six participants). For the TES, trunk extension at 0° was associated with the largest EMG average, and it resulted in the maximum EMG activity the most often (three out of six participants). For the LD, participants obtained their maximum EMG either from chest-supported shoulder extension (three out of six participants) or prone shoulder extension (three out of six participants). Chest-supported shoulder extension, however, had a larger average than prone shoulder extension (0.263 and 0.240, respectively). Although all the aforementioned techniques were superior in their averages, they did not always result in the maximum EMG activity. If an accurate estimate of the true MVC is desired, more than one technique may have to be performed. This research provides additional MVC techniques for each muscle that may elicit the maximum EMG activity.

Keywords: electromyography, maximum voluntary contraction, normalization, physical ergonomics

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Authors: Anita Conti, Riccardo Ossanna, Lindsey A. Quintero, Giamaica Conti, Andrea Sbarbati

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Ischemia/reperfusion (IR) injury induces muscle fiber atrophy and skeletal muscle fiber death with subsequently functionality loss. The heterogeneous pool of cells, especially mesenchymal stem cells, contained in the stromal vascular fraction (SVF) of adipose tissue could promote muscle fiber regeneration. To prevent SVF dispersion, it has been proposed the use of injectable biopolymers that work as cells carrier. A significant element of the extracellular matrix is hyaluronic acid (HA), which has been widely used in regenerative medicine as a cell scaffold given its biocompatibility, degradability, and the possibility of chemical functionalization. Connective tissue micro-fragments enriched with SVF obtained from mechanical disaggregation of adipose tissue were evaluated for IR muscle injury regeneration using low molecular weight HA as a scaffold. IR induction. Hindlimb ischemia was induced in 9 athymic nude mice through the clamping of the right quadriceps using a plastic band. Reperfusion was induced by cutting the plastic band after 3 hours of ischemic period. Contralateral (left) muscular tissue was used as healthy control. Treatment. Twenty-four hours after the IR induction, animals (n=3) were intramuscularly injected with 100 µl of SVF mixed with HA (SVF-HA). Animals treated with 100 µl of HA (n=3) and 100 µl saline solution (n=3) were used as control. Treatment monitoring. All animals were in vivo monitored by magnetic resonance imaging (MRI) at 5, 7, 14 and 18 days post-injury (dpi). High-resolution morphological T2 weighed, quantitative T2 map and Dynamic Contrast-Enhanced (DCE) images were acquired in order to assess the regenerative potential of SVF-HA treatment. Ex vivo evaluation. After 18 days from IR induction, animals were sacrificed, and the muscles were harvested for histological examination. At 5 dpi T2 high-resolution MR images clearly reveal the presence of an extensive edematous area due to IR damage for all groups identifiable as an increase of signal intensity (SI) of muscular and surrounding tissue. At 7 dpi, animals of the SVF-HA group showed a reduction of SI, and the T2relaxation time of muscle tissue of the HA-SVF group was 29±0.5ms, comparable with the T2relaxation time of contralateral muscular tissue (30±0.7ms). These suggest a reduction of edematous overflow and swelling. The T2relaxation time at 7dpi of HA and saline groups were 84±2ms and 90±5ms, respectively, which remained elevated during the rest of the study. The evaluation of vascular regeneration showed similar results. Indeed, DCE-MRI analysis revealed a complete recovery of muscular tissue perfusion after 14 dpi for the SVF-HA group, while for the saline and HA group, controls remained in a damaged state. Finally, the histological examination of SVF-HA treated animals exhibited well-defined and organized fibers morphology with a lateralized nucleus, similar to contralateral healthy muscular tissue. On the contrary, HA and saline-treated animals presented inflammatory infiltrates, with HA slightly improving the diameter of the fibers and less degenerated tissue. Our findings show that connective tissue micro-fragments enriched with SVF induce higher muscle homeostasis and perfusion restoration in contrast to control groups.

Keywords: ischemia/reperfusion injury, regenerative medicine, resonance imaging, stromal vascular fraction

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Authors: Young-Doo Kwon, Seong-Hwa Jun, Dong-Jin Lee, Hyung-Seok Lee

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Ball joints support and guide certain automotive parts that move relative to the frame of the vehicle. Such ball joints are covered and protected from dust, mud, and other interfering materials by ball-joint boots made of rubber—a flexible and near-incompressible material. The boots may experience twisting and bending deformations because of the motion of the joint arm. Thus, environmental and endurance tests of ball-joint boots apply both bending and twisting deformations. In this study, environmental and endurance testing was simulated via the finite element method performed by using a commercial software package. The ranges of principal stress and principal strain values that are known to directly affect the fatigue lives of the parts were sought. By defining these ranges, the number of iterative tests and modifications of the materials and dimensions of the boot can be decreased. Therefore, instead of performing actual part tests, manufacturers can perform standard fatigue tests in trials of different materials by applying only the defined range of stress or strain values.

Keywords: boot, endurance tests, rubber, FEA

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Authors: Ferruh Taspinar, Gulce K. Seyyar, Gamze Kurt, Eda O. Okur, Emrah Afsar, Ismail Saracoglu, Betul Taspinar

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Alterations of physical activity can effect body composition (especially body fat ratio); however body mass index may not sufficient to indicate these minimal differences. The aim of this study was to evaluate the relationship between body composition and physical activity in university students. In this study, 132 university students (mean age; 21.21±1.51) were included. Tanita BC-418 and International Physical Activity Questionnaire (IPAQ) were used to evaluate participants. The correlation between the parameters was analysed via Spearman correlation analysis. Significance level in statistical analyses was accepted is 0.05. The results showed that there was no correlation between body mass index and physical activity (p>0.05). There was a positive correlation between body muscle ratio and physical activity, whereas a negative correlation between body fat ratio and physical activity (p<0.05). This study showed that body fat and muscle ratio affects the level of physical activity in healthy university students. Therefore, we thought that physical activity might reduce effects of the diseases caused by disturbed body composition. Further studies are required to support this idea.

Keywords: body composition, body mass index, physical activity, university student

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Authors: L. Gómez-Limia, I. Franco, T. Blanco, S. Martínez

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European eels (Anguilla anguilla) belong to Anguilliformes order and Anguillidae family. They are generally classified as warm-water fish. Eels have a great commercial value in Europe and Asian countries. Eels can reach high weights, although their commercial size is relatively low in some countries. The capture of larger eels would facilitate the recovery of the species, as well as having a greater number of either glass eels or elvers for aquaculture. In the last years, the demand and the price of eels have increased significantly. However, European eel is considered critically endangered by the International Union for the Conservation of Nature (IUCN) Red List. The biochemical composition of fishes is an important aspect of quality and affects the nutritional value and consumption quality of fish. In addition, knowing this composition can help predict an individual’s condition for their recovery. Fish is known to be important source of protein rich in essential amino acids. However, there is very little information about changes in amino acids composition of European eels with increase in size. The aim of this study was to evaluate the effect of two different weight categories on the amino acids content in muscle tissue of wild European eels. European eels were caught in River Ulla (Galicia, NW Spain), during winter. The eels were slaughtered in ice water immersion. Then, they were purchased and transferred to the laboratory. The eels were subdivided into two groups, according to the weight. The samples were kept frozen (-20 °C) until their analysis. Frozen eels were defrosted and the white muscle between the head and the anal hole. was extracted, in order to obtain amino acids composition. Thirty eels for each group were used. Liquid chromatography was used for separation and quantification of amino a cids. The results conclude that the eels are rich in glutamic acid, leucine, lysine, threonine, valine, isoleucine and phenylalanine. The analysis showed that there are significant differences (p < 0.05) among the eels with different sizes. Histidine, threonine, lysine, hydroxyproline, serine, glycine, arginine, alanine and proline were higher in small eels. European eels muscle presents between 45 and 46% of essential amino acids in the total amino acids. European eels have a well-balanced and high quality protein source in the respect of E/NE ratio. However, eels with higher weight showed a better ratio of essential and non-essential amino acid.

Keywords: European eels, amino acids, HPLC, body size

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Authors: H. M. Ferreira, H. Cockings, D. F. Gordon

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Climate change is driving a transition in the energy sector, with low-carbon energy sources such as hydrogen (H2) emerging as an alternative to fossil fuels. However, the successful implementation of a hydrogen economy requires an expansion of hydrogen production, transportation and storage capacity. The costs associated with this transition are high but can be partly mitigated by adapting the current oil and natural gas networks, such as pipeline, an important component of the hydrogen infrastructure, to transport pure or blended hydrogen. Steel pipelines are designed to withstand fatigue, one of the most common causes of pipeline failure. However, it is well established that some materials, such as steel, can fail prematurely in service when exposed to hydrogen-rich environments. Therefore, it is imperative to evaluate how defects (e.g. inclusions, dents, and pre-existing cracks) will interact with hydrogen under cyclic loading and, ultimately, to what extent hydrogen induced failure will limit the service conditions of steel pipelines. This presentation will explore how the exposure of API 5L X65 to a hydrogen-rich environment and cyclic loads will influence its susceptibility to hydrogen induced failure. That evaluation will be performed by a combination of several techniques such as hydrogen permeation testing (ISO 17081:2014), fatigue crack growth (FCG) testing (ISO 12108:2018 and AFGROW modelling), combined with microstructural and fractographic analysis. The development of a FCG test setup coupled with an electrochemical cell will be discussed, along with the advantages and challenges of measuring crack growth rates in electrolytic hydrogen environments. A detailed assessment of several electrolytic charging conditions will also be presented, using hydrogen permeation testing as a method to correlate the different charging settings to equivalent hydrogen concentrations and effective diffusivity coefficients, not only on the base material but also on the heat affected zone and weld of the pipelines. The experimental work is being complemented with AFGROW, a useful FCG modelling software that has helped inform testing parameters and which will also be developed to ultimately help industry experts perform structural integrity analysis and remnant life characterisation of pipeline steels under representative conditions. The results from this research will allow to conclude if there is an acceleration of the crack growth rate of API 5L X65 under the influence of a hydrogen-rich environment, an important aspect that needs to be rectified instandards and codes of practice on pipeline integrity evaluation and maintenance.

Keywords: AFGROW, electrolytic hydrogen charging, fatigue crack growth, hydrogen, pipeline, steel

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Authors: Kalyan Deepak Kolla, Ketan Paua, Rajkumar Bhagate

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Transmission dynamics occupy major role in customer perception of the product in both senses of touch and quality of sound. The quantity and quality of sound perceived is more concerned with the whine noise of the gears engaged. Whine noise is tonal in nature and tonal noises cause fatigue and irritation to customers, which in turn affect the quality of the product. Transmission error is the usual suspect for whine noise, which can be caused due to misalignments, tolerances, manufacturing variabilities. In-cabin noise is also more sensitive to the gear design. As the details of the gear tooth design and manufacturing are in microns, anything out of the tolerance zone, either in design or manufacturing, will cause a whine noise. This will also cause high variation in stress and deformation due to change in the load and leads to the fatigue failure of the gears. Hence gear design and development take priority in the transmission development process. This paper aims to study such variability by considering five pairs of helical spur gears and their effect on the transmission error, contact pattern and vibration level on the transmission.

Keywords: gears, whine noise, manufacturing variability, mount vibration variability

Procedia PDF Downloads 128

Authors: Shohra Qaderi

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Introduction: Tetanus is a severe infection characterized by the spasm of skeletal muscles that often progresses toward respiratory failure. Acute Renal failure (ARF) is an important complication associated Tetanus infection, occurring in 15%-39% of cases. Presentation of cases: A previous healthy 14-year-old boy was admitted to the Tetanus ward of a hospital in Kabul, presenting with severe muscle spasms. On day four of admission, he started having cola-colored urine with decreased urine output. Due to lack of peritoneal dialysis, he went under hemodialysis in view of rapidly raising in blood urea (from baseline 32 mg/dl to 150 mg/dl) and creatinine from (baseline 0.9 mg/dl to 6.2g/dl). Despite all efforts, he had a sudden cardiac arrest and passed away on day 6 of admission. Discussion: ARF is a complication of tetanus, reported to be mild and non-oliguric. Suggested pathological mechanisms include autonomic dysfunction and rhabdomyolysis, owing to uncontrolled muscle spasms. Autonomic dysfunction, most evident in the first two weeks of infection. Conclusion: The prevalence and mortality of tetanus is high in Afghanistan. Physicians and pediatricians need to be aware of this complication of tetanus so as to take appropriate preventive measures and recognize and manage it early.

Keywords: afghanistan, acute renal failure, child, mortality

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Authors: Yuko Ishiwaka, Tomohiro Yoshida, Tadateru Itoh

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Human makes preparation called readiness potential unconsciously (RP) before awareness of their own decision. For example, when recognizing a button and pressing the button, the RP peaks are observed 200 ms before the initiation of the movement. It has been known that the preparatory movements are acquired before actual movements, but it has not been still well understood how humans can obtain the RP during their growth. On the proposition of why the brain must respond earlier, we assume that humans have to adopt the dangerous environment to survive and then obtain the behavior to cover the various time lags distributed in the body. Without RP, humans cannot take action quickly to avoid dangerous situations. In taking action, the brain makes decisions, and signals are transmitted through the Spinal Cord to the muscles to the body moves according to the laws of physics. Our research focuses on the time lag of the neuron signal transmitting from a brain to muscle via a spinal cord. This time lag is one of the essential factors for readiness potential. We propose a firing pattern controller model of a motor nerve system considered innervation and jitter, which produces time lag. In our simulation, we adopt innervation and jitter in our proposed muscle-skeleton model, because these two factors can create infinitesimal time lag. Q10 Hodgkin Huxley model to calculate action potentials is also adopted because the refractory period produces a more significant time lag for continuous firing. Keeping constant power of muscle requires cooperation firing of motor neurons because a refractory period stifles the continuous firing of a neuron. One more factor in producing time lag is slow or fast-twitch. The Expanded Hill Type model is adopted to calculate power and time lag. We will simulate our model of muscle skeleton model by controlling the firing pattern and discuss the relationship between the time lag of physics and neurons. For our discussion, we analyze the time lag with our simulation for knee bending. The law of inertia caused the most influential time lag. The next most crucial time lag was the time to generate the action potential induced by innervation and jitter. In our simulation, the time lag at the beginning of the knee movement is 202ms to 203.5ms. It means that readiness potential should be prepared more than 200ms before decision making.

Keywords: firing patterns, innervation, jitter, motor nerve system, readiness potential

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Authors: A. Al-Juboori, D. Wexler, H. Li, H. Zhu, C. Lu, A. McCusker, J. McLeod, S. Pannila, Z. Wang

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Squats are a type railhead defect related to rolling contact fatigue (RCF) damage and are considered serious problem affecting a wide range of railway networks across the world. Squats can lead to partial or complete rail failure. Formation mechanics of squats on the surface of rail steel is still a matter of debate. In this work, structural and microstructural observations from ex-service damaged rail both confirms the phases present in white etching layer (WEL) regions and relationship between cracking in WEL and squat defect formation. XRD synchrotron results obtained from the top surfaces of rail regions containing both WEL and squat defects reveal that these regions contain both martensite and retained austenite. Microstructural analysis of these regions revealed the occurrence cracks extending from WEL down into the rail through the squat region. These findings obtained from field rail specimen support the view that WEL contains regions of austenite and martensitic transformation product, and that cracks in this brittle surface layer propagate deeper into the rail as squats originate and grow.

Keywords: squat, white etching layer, rolling contact fatigue, synchrotron diffraction

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Authors: Welder A. Baldassini, Jon J. Ramsey, Marcos R. Chiaratti, Amália S. Chaves, Renata H. Branco, Sarah F. M. Bonilha, Dante P. D. Lanna

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With increased production costs there is a need for animals that are more efficient in terms of meat production. In this context, the role of mitochondrial DNA (mtDNA) on physiological processes in liver, muscle and adipose tissues may account for inter-animal variation in energy expenditures and heat production. The purpose this study was to investigate if the amounts of mtDNA in liver, muscle and adipose tissue (subcutaneous and visceral depots) of Nellore bulls are associated with residual feed intake (RFI) and estimated heat production (EHP). Eighteen animals were individually fed in a feedlot for 90 days. RFI values were obtained by regression of dry matter intake (DMI) in relation to average daily gain (ADG) and mid-test metabolic body weight (BW). The animals were classified into low (more efficient) and high (less efficient) RFI groups. The bulls were then randomly distributed in individual pens where they were given excess feed twice daily to result in 5 to 10% orts for 90 d with diet containing 15% crude protein and 2.7 Mcal ME/kg DM. The heart rate (HR) of bulls was monitored for 4 consecutive days and used for calculation of EHP. Electrodes were fitted to bulls with stretch belts (POLAR RS400; Kempele, Finland). To calculate oxygen pulse (O2P), oxygen consumption was obtained using a facemask connected to the gas analyzer (EXHALYZER, ECOMedics, Zurich, Switzerland) and HR were simultaneously measured for 15 minutes period. Daily oxygen (O2) consumption was calculated by multiplying the volume of O2 per beat by total daily beats. EHP was calculated multiplying O2P by the average HR obtained during the 4 days, assuming 4.89 kcal/L of O2 to measure daily EHP that was expressed in kilocalories/day/kilogram metabolic BW (kcal/day/kg BW0.75). Blood samples were collected between days 45 and 90th after the beginning of the trial period in order to measure the concentration of hemoglobin and hematocrit. The bulls were slaughtered in an experimental slaughter house in accordance with current guidelines. Immediately after slaughter, a section of liver, a portion of longissimus thoracis (LT) muscle, plus a portion of subcutaneous fat (surrounding LT muscle) and portions of visceral fat (kidney, pelvis and inguinal fat) were collected. Samples of liver, muscle and adipose tissues were used to quantify mtDNA copy number per cell. The number of mtDNA copies was determined by normalization of mtDNA amount against a single copy nuclear gene (B2M). Mean of EHP, hemoglobin and hematocrit of high and low RFI bulls were compared using two-sample t-tests. Additionally, the one-way ANOVA was used to compare mtDNA quantification considering the mains effects of RFI groups. We found lower EHP (83.047 vs. 97.590 kcal/day/kgBW0.75; P < 0.10), hemoglobin concentration (13.533 vs. 15.108 g/dL; P < 0.10) and hematocrit percentage (39.3 vs. 43.6 %; P < 0.05) in low compared to high RFI bulls, respectively, which may be useful traits to identify efficient animals. However, no differences were observed between the mtDNA content in liver, muscle and adipose tissue of Nellore bulls with high and low RFI.

Keywords: bioenergetics, Bos indicus, feed efficiency, mitochondria

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Authors: Masoud Alipanah, Sekineh Akbari, Gholamreza Dashab

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Myostatin genes or factor 8 affecting on growth and making differentiation works (GDF8) as a moderator in the development of skeletal muscle inhibitor. If mutations occurs in the coding region of myostatin, alter its inhibitory role and the muscle growth is increased. In this study, blood samples were collected randomly from 60 Kurdish sheep in northern Khorasan and DNA extraction was performed using a modified salt. A fragment 337 bp from exon 3 myostatin gene and-specific primers by using a polymerase chain reaction (PCR) were amplified. In order to detect different forms of an allele at this locus HaeΙΙΙ restriction enzymes and PCR-RFLP analysis were used. Band patterns clarification was performed using agarose gel electrophoresis. The frequency of genotypes mm, Mm, and MM, were respectively detected, 0, 0.15 and 0.85. The allele frequency for alleles m and M, were respectively, 0.07 and 0.93. The statistical analyses indicated that m allele was significantly associated with body weight. The results of this study suggest that the Myostatin gene possibly is a candidate gene that affects growth traits in Kurdish sheep.

Keywords: GDF8 gene, Kurdi Sheep of Northern Khorasan, polymorphism, weight traits

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Authors: Narupon Kunbootsri, Patpiya Sirasaporn

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Low back pain is the most common of chief complaints in chronic pain. Low back pain directly affect to activities daily living and also has high socioeconomic costs. The prevalence of low back pain is high in both genders in all populations. The symptoms of low back pain including, pain at low back area, muscle spasm, tenderness points and stiff back. Trancutanous Electrical Nerve Stimulation (TENS) is one of modalities mainly use for control pain. There was indicated that TENS is wildly use in low back pain, but no scientific data about the flexibility of muscle after TENS in low back pain. Thus the aim of this study was to investigate immediate effect of TENS on flexibility and health status in patients with chronic nonspecific low back pain. Eight chronic nonspecific low back pain patients 1 male and 7 female employed in this study. Participants were diagnosed by a doctor based on history and physical examination. Each participant received treatment at physiotherapy unit. Participants completed Roland Morris Disability Questionnaire (RMDQ), numeric rating scale (NRS) and trunk flexibility before treatment. Each participant received low frequency TENS set at asymmetrical, 10 Hz, 20 minutes per point. Immediately after treatment, participants completed RNS, RMDQ and trunk flexibility again. All participants were treated by only one physiotherapist. There was a statistically significant increased in flexibility immediately after low frequency TENS [mean difference -6.37 with 95%CI were (-8.35)-(-4.39)]. There was a statistically significant decreased in numeric rating scale [mean difference 2.13 with 95%CI were 1.08-3.16]. Roland Morris Disability Questionnaire showed improvement of health status average 44.8% immediately after treatment. In conclusion, the results of the present study indicate that immediately effect after low frequency TENS can decrease pain and improve flexibility of back muscle in chronic nonspecific low back pain patients.

Keywords: low back pain, flexibility, TENS, chronic

Procedia PDF Downloads 523

Authors: Davaakhuu Vandannyam, Amarsaikhan Dashtseren, Oyungoo Badamdorj

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Background: Shift work and extended working hours are increasing in many industries and organization's in the world. Over a 24 hour period, the circadian clock regulates sleep/wake patterns, body temperature, hormone levels, digestion and many other functions. Depending on the time of day or night, the human body is programmed for periods of wakefulness and sleep, high and low body temperature, high and low digestive activity and so on. Shift work is highly prevalent in industrialized societies (>20%) but, when it includes night work, it has pronounced negative effects on sleep, subjective and physiological sleepiness, performance, accident risk, as well as on health outcomes such as cardiovascular disease and certain forms of cancer. Method: In this cross-sectional field study, 634 shift work and day work nurses from a plant were involved, with participation rate of 100% (634 nurses). The general health questionnaire (GHQ-28) and RLS, ESS, ISI, FSS were used to evaluate the level of insomnia, sleepiness, fatigue and restless legs syndrome, respectively. Results: As a result of research on some indicators of health risks caused from work shift, it was proven that prevalence of restless legs syndrome was at 5.5% and 25.9% are in risk of becoming sick, 42.3% are in fatigue, 3.5% in high stage of insomnia and 27.4% are sleepy on duty. Insomnia of nurses mainly affected from long-hour shift, dissatisfaction, workload, lose of focus and use of coffee. There is sleepiness lies in the workplace due to number of shifts, unsatisfactory performance and emergency calls between shifts. It has been determined that risk of sickness influenced by number of shifts in a month and long hour shift, dissatisfaction and use of coffee and divisions are causing restless legs syndrome. Conclusions: Among the nurses, it was found that the prevalence of insomnia is 31.6%, sleepiness 27.4%, fatigue 42.3%, restless legs syndrome 35% and stress 25.9%. These factors of shift work affecting health tend to go up as working hours increase and more common among shift work nurses.

Keywords: shiftwork, insomnia, sleepiness, restless

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Authors: Changhan Ouyang, Zhonglin Xie

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In response to proatherosclerotic factors such as oxidized lipids, or to therapeutic interventions such as angioplasty, stents, or bypass surgery, vascular smooth muscle cells (VSMCs) migrate from the media to the intima, resulting in intimal hyperplasia, restenosis, graft failure, or atherosclerosis. These proatherosclerotic factors also activate autophagy in VSMCs. However, the functional role of autophagy in vascular health and disease remains poorly understood. In the present study, we determined the role of autophagy in the regulation of VSMC migration. Autophagy activity in cultured human aortic smooth muscle cells (HASMCs) and mouse carotid arteries was measured by Western blot analysis of microtubule-associated protein 1 light chain 3 B (LC3B) and P62. The VSMC migration was determined by scratch wound assay and transwell migration assay. Ex vivo smooth muscle cell migration was determined using aortic ring assay. The in vivo SMC migration was examined by staining the carotid artery sections with smooth muscle alpha actin (alpha SMA) after carotid artery ligation. To examine the relationship between autophagy and neointimal hyperplasia, C57BL/6J mice were subjected to carotid artery ligation. Seven days after injury, protein levels of Atg5, Atg7, Beclin1, and LC3B drastically increased and remained higher in the injured arteries three weeks after the injury. In parallel with the activation of autophagy, vascular injury-induced neointimal hyperplasia as estimated by increased intima/media ratio. The en face staining of carotid artery showed that vascular injury enhanced alpha SMA staining in the intimal cells as compared with the sham operation. Treatment of HASMCs with platelet-derived growth factor (PDGF), one of the major factors for vascular remodeling in response to vascular injury, increased Atg7 and LC3 II protein levels and enhanced autophagosome formation. In addition, aortic ring assay demonstrated that PDGF treated aortic rings displayed an increase in neovessel formation compared with control rings. Whole mount staining for CD31 and alpha SMA in PDGF treated neovessels revealed that the neovessel structures were stained by alpha SMA but not CD31. In contrast, pharmacological and genetic suppression of autophagy inhibits VSMC migration. Especially, gene silencing of Atg7 inhibited VSMC migration induced by PDGF. Furthermore, three weeks after ligation, markedly decreased neointimal formation was found in mice treated with chloroquine, an inhibitor of autophagy. Quantitative morphometric analysis of the injured vessels revealed a marked reduction in the intima/media ratio in the mice treated with chloroquine. Conclusion: Autophagy activation increases VSMC migration while autophagy suppression inhibits VSMC migration. These findings suggest that autophagy suppression may be an important therapeutic strategy for atherosclerosis and intimal hyperplasia.

Keywords: autophagy, vascular smooth muscle cell, migration, neointimal formation

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Authors: Chante J. De Klerk

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The potential of music to facilitate superior performance during high to elite level gymnastics conditioning instigated this research. A team of seven gymnasts completed a fixed conditioning programme eight times, alternating the two variable conditions. Four sessions of each condition were conducted: without music (session 1), with music (session 2), without music (3), with music (4), without music (5), and so forth. Quantitative data were collected in both conditions through physiological monitoring of the gymnasts, and administration of the Situational Motivation Scale (SIMS). Statistical analysis of the physiological data made it possible to quantify the presence as well as the magnitude of the musical intervention’s impact on various aspects of the gymnasts' physiological functioning during conditioning. The SIMS questionnaire results were used to evaluate if their motivation towards conditioning was altered by the intervention. Thematic analysis of qualitative data collected through semi-structured interviews revealed themes reflecting the gymnasts’ sentiments towards the data collection process. Gymnast-specific descriptions and experiences of the team as a whole were integrated with the quantitative data to facilitate greater dimension in establishing the impact of the intervention. The results showed positive physiological, motivational, and emotional effects. In the presence of music, superior sympathetic nervous activation, and energy efficiency, with more economic breathing, dominated the physiological data. Fatigue and arousal levels (emotional and physiological) were also conducive to improved conditioning outcomes compared to conventional conditioning (without music). Greater levels of positive affect and motivation emerged in analysis of both the SIMS and interview data sets. Overall, the intervention was found to promote psychophysiological coherence during the physical activity. In conclusion, a strategically constructed musical intervention, designed to accompany a gymnastics conditioning session for high to elite level gymnasts, has ergogenic potential.

Keywords: arousal, fatigue, gymnastics conditioning, motivation, musical intervention, psychophysiological coherence

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Authors: Hsin-Yu Lin, Ching-Hsia Hung

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Obstructive sleep apnea (OSA) is characterized by a complete or partial obstruction of the upper airway during sleep. The vulnerable sites of upper airway collapses are consequences of sleep state-dependent reductions in tone in specific pharyngeal dilators. Clinical examinations reveal multilevel collapses of the upper airway among the patients with OSA. Therefore, an anatomically-based oropharyngeal rehabilitation should comprise a multilevel approach, including retropalatal, retroglossal, hypopharyngeal, temporomandibular, and facial levels, all of which involve different muscle groups and contribute to multifunctional interaction and coordination, such as swallowing, breathing, and phonation. The purpose of the study was to exam the effects of this rehabilitation program with a multilevel approach. In this study, fifteen subjects with newly diagnosed moderate or severe OSA (Apnea-Hypopnea-Index≥15) were randomized into an intervention group and control group. The intervention group (N=8) underwent a 12-week-intervention of a hospital-based rehabilitation program, while the control group (N=7) was kept on the waiting list. The 12-week-intervention comprised an anatomically based multilevel approach. The primary outcome was Polysomnography (PSG) data, and the secondary outcome was oropharyngeal and respiratory muscle function. In the intervention group, Apnea-Hypopnea-Index significantly improved (46.96±19.45 versus 32.78±10.78 events/h, p=0.017) compared with control group (35.77±17.49 versus 42.96±17.32 events/h, p=0.043). While the control group remained no change, the intervention group demonstrated other PSG outcomes significantly improvement, including arousal index (46.04±18.9 versus 32.98±8.35/h, p=0.035), mean SpO2 (92.88±2.1 versus 94.13±1.46%, p=0.039). Besides, the intervention group demonstrated significant improvement in oropharyngeal and respiratory muscle function compared to the control group. This anatomically-based oropharyngeal rehabilitation with a multilevel approach can be proven as a non-invasive therapy for patients with OSA.

Keywords: obstructive sleep apnea, upper airway, oropharyngeal rehabilitation, multilevel approach

Procedia PDF Downloads 82

Authors: Miao Zhang, Limin Liu, Feng Zhi, Panpan Niu, Mengya Yang, Xuemei Zhu, Ying Diao, Jun Wang, Ying Zhao

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Background and Aims: Clinical studies have demonstrated that serum semicarbazide-sensitive amine oxidase (SSAO) activities positively correlate with the progression of atherosclerosis. The aim of the present study is to investigate the effect of SSAO inactivation on the development of atherosclerosis. Methods: Female LDLr knockout (KO) mice were given the Western-type diet for 6 and 9 weeks to induce the formation of early and advanced lesions, and semicarbazide (SCZ, 0.125%) was added into the drinking water to inactivate SSAO in vivo. Results: Despite no impact on plasma total cholesterol levels, abrogation of SSAO by SCZ not only resulted in the enlargement of both early (1.5-fold, p=0.0043) and advanced (1.8-fold, p=0.0013) atherosclerotic lesions, but also led to reduced/increased lesion contents of macrophages/smooth muscle cells (SMCs) (macrophage: ~0.74-fold, p=0.0002(early)/0.0016(advanced); SMC: ~1.55-fold, p=0.0003(early) /0.0001(advanced)), respectively. Moreover, SSAO inactivation inhibited the migration of circulating monocytes into peripheral tissues and reduced the amount of circulating Ly6Chigh monocytes (0.7-fold, p=0.0001), which may account for the reduced macrophage content in lesions. In contrast, the increased number of SMCs in lesions of SCZ-treated mice is attributed to an augmented synthetic vascular SMC phenotype switch as evidenced by the increased proliferation of SMCs and accumulation of collagens in vivo. Conclusion: SSAO inactivation by SCZ promotes the phenotypic switch of SMCs and the development of atherosclerosis. The enzymatic activity of SSAO may thus represent a potential target in the prevention and/or treatment of atherosclerosis.

Keywords: atherosclerosis, phenotype switch of smooth muscle cells, SSAO/VAP-1, semicarbazide

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Authors: Long-Shan Wu, Ming-Chen Ko, Chien-Chang Ho, Po-Fu Lee, Jenn-Woei Hsieh, Ching-Yu Tseng

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This study aimed to determine the effects of whole-body vibration (WBV) training on lower-extremity muscle strength and balance control performance among community-dwelling middle-aged and older adults in the United States. Twenty-nine participants without any contraindication of performing WBV exercise completed all the study procedures. Participants were randomly assigned to do body weight exercise with either an individualized vibration frequency and amplitude, a fixed vibration frequency and amplitude, or no vibration. Isokinetic knee extensor power, limits of stability, and sit-to-stand tests were performed at the baseline and after 8 weeks of training. Neither the individualized frequency-amplitude WBV training protocol nor the fixed frequency-amplitude WBV training protocol improved isokinetic knee extensor power. The limits of stability endpoint excursion score for the individualized frequency-amplitude group increased by 8.8 (12.9%; p = 0.025) after training. No significant differences were observed in fixed and control group. The maximum excursion score for the individualized frequency-amplitude group at baseline increased by 9.2 (11.5%; p = 0.006) after training. The average weight transfer time score significantly decreased by 0.21 s in the fixed group. The participants in the individualized group showed a significant increase (3.2%) in weight rising index score after 8 weeks of WBV training. These results suggest that 8 weeks of WBV training improved limit of stability and sit-to-stand performance. Future studies need to determine whether WBV training improves other factors that can influence posture control.

Keywords: whole-body vibration training, muscle strength, balance control, middle-aged and older adults

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Authors: Wei Yongxiang, Zhu Haoyue, Tang Heng, Yuan Qunwei

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In order to study the preparation method of gear fatigue load spectrum for loaders, the load signal of four typical working conditions of loader is collected. The signal that reflects the law of load change is obtained by preprocessing the original signal. The torque of the drive axle is calculated by using the rain flow counting method. According to the operating time ratio of each working condition, the two-dimensional load spectrum based on the real working conditions of the drive axle of loader is established by the cycle extrapolation and synthesis method. The two-dimensional load spectrum is converted into one-dimensional load spectrum by means of the mean of torque equal damage method. Torque amplification includes the maximum load torque of the main reduction gear. Based on the theory of equal damage, the accelerated cycles are calculated. In this way, the load spectrum of the loading condition of the drive axle is prepared to reflect loading condition of the loader. The load spectrum can provide reference for fatigue life test and life prediction of loader drive axle.

Keywords: load spectrum, axle, torque, rain-flow counting method, extrapolation

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Authors: Subodh N. Patel, Abhijit Pusty, Manashi Adhikary, Sandip Bhattacharyya

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The steam superheater (SH) is a coil type heat exchanger which is used to produce superheated steam or to convert the wet steam to dry steam (69.6 kg/cm² and 495°C), generated by a boiler. There were two superheaters in the system, SH I and SH II. SH II is a set of tubes that faces the initial interaction with flue gas at high temperature followed by SH I tubes. After a service life of 2100 hours, a tube in the SH II found to be punctured. Dye penetrant test revealed that out of 50 such tubes, 14 more tubes had severe cracks at a similar location. The failure was investigated in detail. The materials and scale were characterized by optical microscope and advance characterization technique. Scale, observed on fracture surface, was characterized under scanning electron microscope and Raman spectroscopy. Stresses acting on the tubes in working condition were analyzed by finite element method software, ANSYS. Cyclic stresses were observed in the simulation at the same prone location due to restriction in expansion of tubes. Based on scale characterization and stress analysis, it was concluded that the tube failed in thermo-mechanical fatigue. Finally, prevention and control measures were taken to avoid such failure in the future.

Keywords: finite element analysis, oxide scale, superheater tube, thermomechanical fatigue

Procedia PDF Downloads 98