Academic literature on the topic 'Lean tissue mass loss'
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Journal articles on the topic "Lean tissue mass loss"
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Spungen, Ann M., Jack Wang, Richard N. Pierson, and William A. Bauman. "Soft tissue body composition differences in monozygotic twins discordant for spinal cord injury." Journal of Applied Physiology 88, no. 4 (April 1, 2000): 1310–15. http://dx.doi.org/10.1152/jappl.2000.88.4.1310.
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To determine the effect of paralysis on body composition, eight pairs of male monozygotic twins, one twin in each pair with paraplegia, were studied by dual-energy X-ray absorptiometry. Significant loss of total body lean tissue mass was found in the paralyzed twins compared with their able-bodied co-twins: 47.5 ± 6.7 vs. 60.1 ± 7.8 (SD) kg ( P < 0.005). Regionally, arm lean tissue mass was not different between the twin pairs, whereas trunk and leg lean tissue masses were significantly lower in the paralyzed twins: −3.0 ± 3.3 kg ( P < 0.05) and −10.1 ± 4.0 kg ( P < 0.0005), respectively. Bone mineral content of the total body and legs was significantly related to lean tissue mass in the able-bodied twins ( R = 0.88 and 0.98, respectively) but not in the paralyzed twins. However, the intrapair difference scores for bone and lean tissue mass were significantly related ( R = 0.80 and 0.81, respectively). The paralyzed twins had significantly more total body fat mass and percent fat per unit body mass index than the able-bodied twins: 4.8 kg ( P < 0.05) and 7 ± 2% ( P< 0.01). In the paralyzed twins, total body lean tissue was significantly lost (mostly from the trunk and legs), independent of age, at a rate of 3.9 ± 0.2 kg per 5-yr period of paralysis ( R = 0.87, P < 0.005). Extreme disuse from paralysis appears to contribute to a parallel loss of bone with loss of lean tissue in the legs. The continuous lean tissue loss may represent a form of sarcopenia that is progressive and accelerated compared with that in ambulatory individuals.
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Voronkov, L. G., К. V. Voitsekhovska, S. V. Fedkiv, and V. I. Koval. "Anthropometric parameters and body tissue compartments of patients with chronic heart failure and reduced left ventricular ejection fraction depending on weight loss within the previous 6 months." Ukrainian Journal of Cardiology 26, no. 3 (August 1, 2019): 53–61. http://dx.doi.org/10.31928/1608-635x-2019.3.5361.
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The aim – to compare the anthropometric parameters and body tissue compartments of patients with chronic heart failure (CHF) and reduced left ventricular ejection fraction depending on weight loss ≥ 6 % of total body weight within the previous 6 months. Materials and methods. 77 stable patients with chronic heart failure 25–75 years old, NYHA class II–IV, with left ventricular ejection fraction ≤ 35 % were screened. The criterion for the patients group distribution was the weight loss in the last 6 months ≥ 6 % according to the European guidelines for the diagnosis and treatment of CHF. Body composition was measured by dual-energy X-ray absorptiometry. Patients were included in a clinical compensation phase. Results and discussion. Weight loss ≥ 6 % within the previous 6 months was observed in 34 (44.2 %) patients. Patients with weight loss ≥ 6 % had a significantly smaller fat tissue mass (p=0.002) and lean tissues mass (p=0.039), which was confirmed by comparing the normalized indicators of these tissue arrays relative to growth. The limb muscle mass (p=0.006) and the limb muscle mass index (p=0.002) were significantly less in this group of patients. The number of lost kilograms over the past 6 months correlated inversely with the muscle mass index of limbs (r=–0.411, p=0.001), body weight (r=–0.381, p=0.001), muscle mass of limbs (r=–0.360, p=0.001), hip circumference (r=–0.352, p=0.002), body surface area (r=–0.345, p=0.009), waist circumference (r=–0.334, p=0.003), body mass index (r=–0.330, p=0.004), shoulder arm circumference (r=–0.280, p=0.015), lean tissue mass (r=–0.277, p=0.015), skin-fat fold thickness under the scapula (r=–0.273, p=0.018), fat mass tissue (r=–0.269, p=0.018), the circumference of tense arm (r=–0.262, p=0.023), the ratio of fat tissue to height (r=–0.253, p=0.026), the fat tissue index (r=–0.233, p=0.042), and correlated positively with the percentage of bone tissues (r=0.250, p=0.028). Conclusions. Weight loss ≥ 6 % over the past 6 months in patients with CHF and reduced ventricular ejection fraction was observed in 34 (44.2 %) patients. Patients with CHF and weight loss ≥ 6 % were significantly older, had a higher NYHA class, lower body weight, body mass index, shoulder circumference of a tense and relaxed arm, waist and hip circumferences, thickness skin and fat folds over the biceps, triceps and under the scapula. Patients with a body weight loss of ≥ 6 % over the past 6 months had a significantly lower percentage of fat tissue, fat mass and lean tissue mass, indexes of fat mass and muscular tissue of limbs. Patients in groups did not differ in terms of mineral bone mass.
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Zdanowicz, Martin M. "Use of Growth Hormone and Insulin-like Growth Factor 1 for Treatment of Tissue Wasting in Catabolic Conditions." Hospital Pharmacy 35, no. 2 (February 2000): 163–68. http://dx.doi.org/10.1177/001857870003500219.
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Trauma, surgery, burn injury, sepsis, prolonged bed rest, cancer, and AIDS are examples of catabolic states that can lead to a significant loss of lean body tissues and skeletal muscle. The physiologic stresses associated with these catabolic conditions can impair immune function, alter drug response, and delay the recovery process. Although enhanced nutritional supplementation is a mainstay for treating tissue wasting in these conditions, it is of limited effectiveness in reversing skeletal muscle protein loss or enhancing anabolism in lean body tissues. The use of anabolic hormones such as Growth Hormone (GH) or Insulin-Like Growth Factor 1 (IGF-1) to limit lean body wasting and preserve muscle mass in these conditions has been widely investigated. This article was designed to give pharmacists and patient care professionals an overview of recent literature involving anabolic hormone treatment of tissue wasting. The use of these agents in the clinical setting may undergo significant expansion in the near future.
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German, Alexander J., Shelley Holden, Thomas Bissot, Penelope J. Morris, and Vincent Biourge. "Changes in body composition during weight loss in obese client-owned cats: Loss of lean tissue mass correlates with overall percentage of weight lost." Journal of Feline Medicine and Surgery 10, no. 5 (October 2008): 452–59. http://dx.doi.org/10.1016/j.jfms.2008.02.004.
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Obesity is one of the most common medical diseases in cats, but there remains little information on success of weight loss regimes in obese client-owned cats. No information currently exists on body composition changes during weight loss in clinical cases. Twelve obese client-owned cats undertook a weight loss programme incorporating a high-protein low fat diet. Body composition was quantified by dual-energy X-ray absorptiometry, before and after weight loss. Mean (±standard deviation) weight loss was 27±6.8% of starting weight, and mean rate of weight loss was 0.8±0.32% per week. Mean energy allocation during weight loss was 32±7.0 kcal/kg target weight. Mean composition of tissue lost was 86:13:1 (fat:lean:bone mineral). The proportion of lean tissue loss was positively associated with overall percentage of weight loss (simple linear regression, r2=44.2%, P=0.026). Conventional weight loss programmes produce safe weight loss, but lean tissue loss is an inevitable consequence in cats that lose significant proportions of their starting body weight.
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Nindl, Bradley C., Everett A. Harman, James O. Marx, Lincoln A. Gotshalk, Peter N. Frykman, Eric Lammi, Chris Palmer, and William J. Kraemer. "Regional body composition changes in women after 6 months of periodized physical training." Journal of Applied Physiology 88, no. 6 (June 1, 2000): 2251–59. http://dx.doi.org/10.1152/jappl.2000.88.6.2251.
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Data are lacking regarding regional morphological changes among women after prolonged physical training. This study employed dual-energy X-ray absorptiometry to assess changes in whole body and regional (i.e., trunk, legs, arms) fat mass, lean mass, and bone mineral content body composition adaptations in 31 healthy women pre-, mid-, and post-6 mo of periodized physical training. These results were compared with those of 1) a control group of women who had not undergone the training program and were assessed pre- and post-6 mo and 2) a group of 18 men that was tested only once. Additionally, magnetic resonance imaging was used to assess changes in muscle morphology of the thigh in a subset of 11 members of the training group. Physical training consisted of a combination of aerobic and resistance exercise in which the subjects engaged for 5 days/wk for 24 wk. Overall, the training group experienced a 2.2% decrease, a 10% decrease, and a 2.2% increase for body mass, fat mass, and soft tissue lean mass, respectively. No changes in bone mineral content were detected. The women had less of their soft tissue lean mass distributed in their arms than did the men, both before and after the women were trained. Novel to this study were the striking differences in the responses in the tissue composition of the arms (31% loss in fat mass but no change in lean mass) compared with the legs (5.5% gain in lean mass but no change in fat mass). There was a 12% fat loss in the trunk with no change in soft tissue lean mass. Dual-energy X-ray absorptiometry and magnetic resonance imaging fat mass measurements showed good agreement ( r = 0.72–0.92); their lean mass measurements were similar as well, showing ∼5.5% increases in leg lean tissue. These findings show the importance of considering regional body composition changes, rather than whole body changes alone when assessing the effects of a periodized physical training program.
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Lachey, J., A. Koncarevic, J. Ucran, R. S. Pearsall, M. L. Sherman, and J. Seehra. "Effect of a soluble activin receptor type IIB on androgen-deprivation-induced effects on body composition." Journal of Clinical Oncology 27, no. 15_suppl (May 20, 2009): 5133. http://dx.doi.org/10.1200/jco.2009.27.15_suppl.5133.
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5133 Background: Androgen deprivation therapy (ADT) is a well-established treatment for hormone sensitive prostate cancer, but is associated with adverse side effects including loss of bone and lean mass and increased adipose mass. Activin receptor type IIB (ActRIIB) signaling is necessary for the negative regulation of lean tissue mass and treatment with a non-signaling, decoy ActRIIB results in a robust increase in lean tissue mass. Methods: Similar to ADT patients, orchiectomized (ORX) mice lose bone and lean mass and gain fat mass. To determine the therapeutic potential of inhibiting ActRIIB signaling to reduce the negative effects associated with ADT, we treated sham-operated (SHAM) and orchiectomized (ORX) mice with RAP-031, a fusion protein comprised of a form of the extracellular domain of ActRIIB linked to a murine Fc. Mice received twice weekly injections for 10 weeks with either vehicle (VEH) or 10 mg/kg RAP-031 (RAP). NMR scanning was used to determine body composition and whole body DEXA scans were performed to determine bone mineral density (BMD). Results: ORX resulted in a 4.4% decrease in BMD, an 18% reduction in lean tissue and a 41.6% increase in adiposity compared to the VEH-SHAM cohort. Both RAP-031treated groups of mice had significantly increased BMD and lean tissue mass and decreased adipose mass compared to their respective VEH groups. However, BMD, lean tissue and adiposity were not significantly different between the VEH-SHAM and RAP-ORX groups. These data illustrate that RAP-031 treatment completely attenuates ORX-induced alterations in bone, lean and fat mass. Conclusions: These data support the hypothesis that treatment with a form of soluble ActRIIB can offset negative side effects of ADT and have significant therapeutic implications for the treatment of patients with prostate cancer. [Table: see text] [Table: see text]
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Wu, Shenghui, Kyung-Shin Park, and Joseph B. McCormick. "Effects of Exercise Training on Fat Loss and Lean Mass Gain in Mexican-American and Korean Premenopausal Women." International Journal of Endocrinology 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/5465869.
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We investigated the effect of exercise training on body composition change in women. Nineteen Mexican-American and 18 Korean premenopausal overweight/obese women were randomized into one of the following groups: control, low-intensity training group (LI), and high-intensity training group (HI). Subjects completed 12 weeks of training at 50–56% maximal oxygen consumption (LI) or 65–70% maximal oxygen consumption (HI). Body composition components were measured at baseline and after training using dual-energy X-ray absorptiometry for Mexican-Americans, while whole-body composition was measured by the direct segmental multifrequency bioelectrical impedance analysis and abdominal fat was measured by single-slice computed tomography for Koreans. Data were analyzed using mixed-model repeated measures independent of age, ethnicity, and body mass index (BMI). Exercise training showed a significant effect on BMI, fat percentage, fat mass, lean mass, and visceral adipose tissue area. HI significantly decreased fat mass and fat percentage but increased lean mass (all P<0.05). LI significantly reduced BMI, fat mass, fat percentage, and visceral adipose tissue area but increased lean mass (all P<0.05). Exercise training had a beneficial effect on reducing BMI, fat percentage, fat mass, and visceral adipose tissue area but had no effect on increasing lean mass for Mexican-American and Korean premenopausal overweight/obese women.
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Groom, Derrick J. E., Jessica E. Deakin, M. Collette Lauzau, and Alexander R. Gerson. "The role of humidity and metabolic status on lean mass catabolism in migratory Swainson's thrushes ( Catharus ustulatus )." Proceedings of the Royal Society B: Biological Sciences 286, no. 1909 (August 28, 2019): 20190859. http://dx.doi.org/10.1098/rspb.2019.0859.
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Migratory birds use protein as a fuel source during flight, but the mechanisms and benefits of protein catabolism during migration are poorly understood. The tissue-specific turnover rate hypothesis proposes that lean mass loss depends solely on the constitutive rate of protein degradation for a given tissue, and is therefore independent of metabolic rate or environmental stimuli. However, it has been demonstrated that environmental stressors such as humidity affect the rate of lean mass catabolism during flight, a finding that seemingly contradicts the tissue-specific turnover rate hypothesis. In order to resolve this, we placed migratory Swainson's thrushes in either high (HEWL) or low (LEWL) evaporative water loss conditions at rest and while undergoing simulated migratory flight at 8 m s −1 in a wind tunnel to test the impact of both environmental stressors and metabolic rate on the rate of protein breakdown. The total quantity and rate of lean mass loss was not different between flight and rest birds, but was affected by humidity condition, with HEWL losing significantly more lean mass. These results show that the rate of protein breakdown in migratory birds is independent of metabolic rate, but it can be augmented in response to environmental stressors.
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LeBlanc, A. D., V. S. Schneider, H. J. Evans, C. Pientok, R. Rowe, and E. Spector. "Regional changes in muscle mass following 17 weeks of bed rest." Journal of Applied Physiology 73, no. 5 (November 1, 1992): 2172–78. http://dx.doi.org/10.1152/jappl.1992.73.5.2172.
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This work reports on the muscle loss and recovery after 17 wk of continuous bed rest and 8 wk of reambulation in eight normal male volunteers. Muscle changes were assessed by urinary levels of 3-methylhistidine (3-MeH), nitrogen balance, dual-photon absorptiometry (DPA), magnetic resonance imaging (MRI), and isokinetic muscle performance. The total body lean tissue loss during bed rest calculated from nitrogen balance was 3.9 +/- 2.1 (SD) kg (P < 0.05). Although the total loss is minimal, DPA scans showed that nearly all of the lean tissue loss occurred in the lower limbs. Similarly, MRI muscle volume measurements showed greater percent loss in the limbs relative to the back muscles. MRI, DPA, and nitrogen balance suggest that muscle atrophy continued throughout bed rest with rapid recovery after reambulation. Isokinetic muscle strength decreased significantly (P < 0.05) in the thigh and calf with no loss in the arms and with rapid recovery during reambulation. We conclude that there is great variability in the degree and location of muscle loss in bed rest and that the lower limb muscles are primarily affected.
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Visser, Wesley J., Anneke M. E. de Mik-van Egmond, Reinier Timman, David Severs, and Ewout J. Hoorn. "Risk Factors for Muscle Loss in Hemodialysis Patients with High Comorbidity." Nutrients 12, no. 9 (August 19, 2020): 2494. http://dx.doi.org/10.3390/nu12092494.
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With expanding kidney transplantation programs, remaining hemodialysis patients are more likely to have a high comorbidity burden and may therefore be more prone to lose muscle mass. Our aim was to analyze risk factors for muscle loss in hemodialysis patients with high comorbidity. Fifty-four chronic hemodialysis patients (Charlson Comorbidity Index 9.0 ± 3.4) were followed for 20 weeks using 4-weekly measurements of lean tissue mass, intracellular water, and body cell mass (proxies for muscle mass), handgrip strength (HGS), and biochemical parameters. Mixed models were used to analyze covariate effects on LTM. LTM (−6.4 kg, interquartile range [IQR] −8.1 to −4.8), HGS (−1.9 kg, IQR −3.1 to −0.7), intracellular water (−2.11 L, IQR −2.9 to −1.4) and body cell mass (−4.30 kg, IQR −5.9 to −2.9) decreased in all patients. Conversely, adipose tissue mass increased (4.5 kg, IQR 2.7 to 6.2), resulting in no significant change in body weight (−0.5 kg, IQR −1.0 to 0.1). Independent risk factors for LTM loss over time were male sex (−0.26 kg/week, 95% CI −0.33 to −0.19), C-reactive protein above median (−0.1 kg/week, 95% CI −0.2 to −0.001), and baseline lean tissue index ≥10th percentile (−1.6 kg/week, 95% CI −2.1 to −1.0). Age, dialysis vintage, serum albumin, comorbidity index, and diabetes did not significantly affect LTM loss over time. In this cohort with high comorbidity, we found universal and prominent muscle loss, which was further accelerated by male sex and inflammation. Stable body weight may mask muscle loss because of concurrent fat gain. Our data emphasize the need to assess body composition in all hemodialysis patients and call for studies to analyze whether intervention with nutrition or exercise may curtail muscle loss in the most vulnerable hemodialysis patients.
Dissertations / Theses on the topic "Lean tissue mass loss"
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Kotarsky, Christopher Joseph. "Strategies for the Reduction of Adipose Tissue and Retention of Muscle Mass in Overweight Individuals." Diss., North Dakota State University, 2020. https://hdl.handle.net/10365/32044.
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Purpose: The purpose of this study was to determine whether time-restricted feeding (TRF) was an effective dietary strategy for reducing fat mass and preserving fat-free mass while evaluating potential changes in cardiometabolic biomarkers, hormones, muscle performance, and energy and macronutrient intake after eight weeks of aerobic exercise and resistance training in overweight and obese adults. Methods: This study was a randomized, controlled trial. Sedentary, overweight and obese adults (mean ± SD; age: 44.48 ± 7.28 years; BMI: 29.61 ± 2.62 kg/m2; females: 85.71%; males: 14.29%) were randomly assigned to a TRF or normal feeding (NF) dietary strategy group. The TRF group consumed all calories between 1200 and 2000 hours, whereas the NF group ate their typical diet. All groups completed eight weeks of aerobic exercise and supervised resistance training. Body composition, muscle performance, energy and macronutrient intake, physical activity, and physiological variables were assessed week zero and week nine. Results: A total of 21 participants completed the study (NF: n = 10; TRF: n = 11). A mild energy restriction was seen for the TRF (~300 kcal/day, 14.0%) and NF (~250 kcal/d, 11.0%) groups between baseline and week seven. Losses of total body mass were significantly greater for TRF (3.3%) relative to NF (0.2%), of which TRF had significantly greater losses of fat mass (9.0%) compared to NF (3.3%) despite similar reductions in energy intake. Lean mass increased across the intervention for both TRF (0.6%) and NF (1.9%), with no group differences. Conclusion: These data support the use of TRF and concurrent exercise training as a short-term dietary strategy for reducing fat mass and preserving lean mass in overweight and obese adults.
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Williams, David. "Phosphatidic Acid Increases Lean Body Tissue and Strength In Resistance Trained Men." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5575.
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Phosphatidic Acid (PA) is a natural phospholipid compound derived from lecithin which is commonly found in egg yolk, grains, fish, soybeans, peanuts and yeast. It has been suggested that PA is involved in several intracellular processes associated with muscle hypertrophy. Specifically, PA has been reported to activate protein synthesis through the mammalian target of rapamycin (mTOR) signaling pathway and thereby may enhance the anabolic effects of resistance training. To our knowledge, no one has examined the effect of PA supplementation in humans while undergoing a progressive resistance training program. To examine the effect of PA supplementation on lean soft tissue mass (LM) and strength after 8 weeks of resistance training. Fourteen resistance-trained men (mean [plus or minus] SD; age 22.7 [plus or minus] 3.3 yrs; height: 1.78 [plus or minus] 0.10m; weight: 89.3 [plus or minus] 16.3 kg) volunteered to participate in this randomized, double-blind, placebo-controlled, repeated measures study. The participants were assigned to a PA group (750mg/day; Mediator, ChemiNutra, MN, n=7) or placebo group (PL; rice flower; n=7), delivered in capsule form that was identical in size, shape and color. Participants were tested for 1RM strength in the bench press (BP) and squat (SQ) exercise. LM was measured using dual-energy X-ray absorptiometry. After base line testing, the participants began supplementing PA or PL for 8 weeks during a progressive resistance training program intended for muscular hypertrophy. Data was analyzed using magnitude-based inferences on mean changes for BP, SQ and LM. Furthermore, the magnitudes of the inter-relationships between changes in total training volume and LM were interpreted using Pearson correlation coefficients, which had uncertainty (90% confidence limits) of approximately +0.25. In the PA group, the relationship between changes in training volume and LM was large (r=0.69, [plus or minus] 0.27; 90%CL), however, in the PL group the relationship was small (r=0.21, [plus or minus] 0.44; 90%CL). PA supplementation was determined to be likely beneficial at improving SQ and LM over PL by 26% and 64%, respectively. The strong relationship between changes in total training volume and LM in the PA group suggest that greater training volume most likely lead to the greater changes in LM, however, no such relationship was found with PL group. For the BP data, the PA group resulted in a 42% greater increase in strength over PL, although the effect was considered unclear. While more research is needed to elucidate mechanism of action; the current findings suggest that in experienced resistance trained men supplementing 750mg PA per day for 8 weeks may likely benefit greater changes in muscle mass and strength compared with resistance training only.M.S.
Masters
Child, Family and Community Sciences
Education and Human Performance
Sport and Exercise Sciences; Applied Exercise Physiology
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Phillips, Emily Marie. "A Study to Examine the Effects of Resistance Training on Motor Function, Cognitive Performance, Physical Strength, Body Composition, and Mood in Adults with Down Syndrome." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1584440781994656.
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St-Onge, Maxime. "Impact de l'entraînement en musculation et d'un régime hypocalorique sur la composition corporelle et la dépense énergétique de femmes post ménopausées en surpoids ou obèses." Thèse, 2009. http://hdl.handle.net/1866/6476.
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Martini, Eduardo Pereira. "Relationship between changes in body composition and maximal forearm strength in elite judo athletes." Master's thesis, 2011. http://hdl.handle.net/10400.5/8881.
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Mestrado em Exercício e SaúdeThe purpose of this study was twofold: a) to analyze the association between body composition (BC) changes, from a weight stability period to prior competition, on forearm maximal strength and b) to understand if a grip strength (GS) deficit between dominant (D) and non-dominant (ND) hands exists and if it is affected by total and regional BC. A total of 27 elite male athletes, age of 23.2±2.8 years, were evaluated at baseline (weight stability period) and 1–3 days before competition, with a time difference of approximately 1-month. BC was assessed by DXA, specifically total and regional fat mass (FM), lean soft-tissue (LST), and bone mineral content (BMC). Maximal forearm isometric strength was performed by handgrip measurement. Comparison of means and Pearson’s coefficient of correlation was used. No significant changes were observed in GS, both at the D and ND hands. The subjects lost 1.2±2.7 % of initial body weight (p<0.05), however no changes where observed in total and regional BC (p<0.05). No association was found between total and regional BC with changes in GS of the right (D) hand, however we found a negative relation between changes in left hand (ND) GS, specifically with LST (r=-0.434;p<0.027), and weight (r=-0.497;p<0.01). GS is significantly higher (p<0.05) in D hand compared to ND hand, both at the weight stability period (-2.11±3.2 kg) and prior competition (-2.6±3.7 kg). No association was found between total and regional BC with the strength deficit between ND and D hands. In conclusion these findings indicate that changes in total and appendicular BC, specifically FM are associated with changes in GS from the ND hand. At both moments, D hand was significantly stronger than ND hand. Furthermore, total and regional BC was not related to GS deficit between ND and D hands in elite judo athletes.
RESUMO : Este estudo pretendeu: a) Analisar as associações entre variações da composição corporal (CC), de um período de peso estável até ao período anterior a uma competição; b) Compreender se existe um deficit de força máxima de preensão manual (FMPM) entre a mão não-dominante (ND) e dominante (D), e se presente, verificar o efeito da CC total e regional no deficit de FMPM. Um total de 27 atletas masculinos de elite, com idade média de 23,2±2,8, foram avaliados no período de peso estável e 1-3 dias antes da competição. A CC foi avaliada pela DXA, especificamente massa gorda (MG), massa isenta de gordura e osso (MIGO) e conteúdo mineral ósseo (CMO) total e regional. A força isométrica máxima do antebraço foi avaliada pelo teste de preensão manual. Comparação de médias e coeficiente de correlação de Pearson foram utilizados. Não se verificaram alterações significativas na FMPM bilateral. Os sujeitos perderam 1,2±2,7 % do peso inicial (p<0.05) contudo não se observaram alterações na CC total e regional. Não se observaram associações da CC com as alterações na FMPM da mão direita (D), embora se verificasse uma associação negativa entre a FMPM da mão esquerda (ND) e as variações na MIGO (r=-0,434;p<0,027) e peso (r=-0,497;p<0,01). A FMPM foi significativamente mais alta na mão D comparada com a ND no período de peso estável (2,11±3,2 kg) e antes da competição (-2,6±3,7kg). Não se verificou associação entre a CC e o deficit de FMPM. Em conclusão, estes resultados indicam que variações da CC total e apendicular, especificamente a MG, estão associadas a variações de FMPM da mão ND. A mão D foi significativamente mais forte que a ND nos dois momentos de avaliação. Adicionalmente, não se observou qualquer associação entre a CC total e regional com o deficit de FMPM em judocas Portugueses de elite.
Books on the topic "Lean tissue mass loss"
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Leutholtz, Brian C. The effects of exercise training and severe caloric restriction on lean-body mass in the obese. 1991.
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Baker, Melany. Intermittent Fasting 101: The Guide to Intermittent Fasting Helps You Lose Weight and Get Lean Muscle Mass, Weight Loss and to Burning Fat Thanks to 16/8 Technique. Independently Published, 2019.
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Puthucheary, Zudin, Hugh Montgomery, Nicholas Hart, and Stephen Harridge. Skeletal Muscle Mass Regulation in Critical Illness. Oxford University Press, 2014. http://dx.doi.org/10.1093/med/9780199653461.003.0035.
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Muscle is a dynamic, plastic, and malleable tissue that is highly sensitive to mechanical and metabolic signals. Muscle mass is regulated by protein homeostasis, with protein being continually turned over, reflecting a balance between synthesis and breakdown. This chapter discusses the effect of critical illness on skeletal muscle mass, protein homeostasis, and the intracellular signalling driving anabolism and catabolism. The focus will be on the unique challenges to which the skeletal muscle are exposed, such as inflammation, sepsis, sedation, and inadequate nutrition, which, in combination with the disuse signals of immobilization and bed rest, engender dramatic changes in muscle structure and function. The mechanisms regulating muscle loss during critical illness are being unravelled, but many questions remain unanswered. Detailed understanding of these mechanisms will help drive strategies to minimize or prevent intensive care-acquired muscle weakness and the long-term consequences experienced by ICU survivors.
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Malina, Robert M. The influence of physical activity and training on growth and maturation. Edited by Neil Armstrong and Willem van Mechelen. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198757672.003.0032.
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Physical activity in the general youth population and systematic training for sport among young athletes seems to have no effect on size attained and rate of growth in height, or on maturity status and timing. However, activity and training may influence body weight and composition. While both favourably influence bone mineral, variable effects are noted in some sports. Activity has a minimal effect on fatness in normal weight youth, but regular training generally has a positive influence on fatness in youth athletes. Data for fat-free/lean tissue mass are suggestive, but limited. Constitutional factors play a central role in the selection and retention of young athletes in a sport.
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Casaer, Michael P., and Greet Van den Berghe. Nutrition support in acute cardiac care. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199687039.003.0032.
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Malnutrition in cardiac and critical illness is associated with a compromised clinical outcome. The aim of nutrition therapy is to prevent these complications and particularly to attenuate lean tissue wasting and the loss of muscle force and of physical function. During the last decade, several well-powered randomized controlled nutrition trials have been performed. Their results challenge the existing nutrition practices in critically ill patients. Enhancing the nutritional intake and the administration of specialized formulations failed to evoke clinical benefit. Some interventions even provoked an increased mortality or a delayed recovery. These unexpected new findings might be, in part, caused by an important leap forward in the methodological quality in the recent trials. Perhaps reversing early catabolism in the critically ill patient by nutrition or anabolic interventions is impossible or even inappropriate. Nutrients effectively suppress the catabolic intracellular autophagy pathway. But autophagy is crucial for cellular integrity and function during metabolic stress, and consequently its inhibition early in critical illness might be deleterious. Evidence from large nutrition trials, particularly in acute cardiac illness, is scarce. Nutrition therapy is therefore focused on avoiding iatrogenic harm. Some enteral nutrition is administered if possible and eventually temporary hypocaloric feeding is tolerated. Above all, the refeeding syndrome and other nutrition-related complications should be prevented. There is no indication for early parenteral nutrition, increased protein doses, specific amino acids, or modified lipids in critical illness.
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Casaer, Michael P., and Greet Van den Berghe. Nutrition support in acute cardiac care. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199687039.003.0032_update_001.
Full textAbstract:
Malnutrition in cardiac and critical illness is associated with a compromised clinical outcome. The aim of nutrition therapy is to prevent these complications and particularly to attenuate lean tissue wasting and the loss of muscle force and of physical function. During the last decade, several well-powered randomized controlled nutrition trials have been performed. Their results challenge the existing nutrition practices in critically ill patients. Enhancing the nutritional intake and the administration of specialized formulations failed to evoke clinical benefit. Some interventions even provoked an increased mortality or a delayed recovery. These unexpected new findings might be, in part, caused by an important leap forward in the methodological quality in the recent trials. Perhaps reversing early catabolism in the critically ill patient by nutrition or anabolic interventions is impossible or even inappropriate. Nutrients effectively suppress the catabolic intracellular autophagy pathway. But autophagy is crucial for cellular integrity and function during metabolic stress, and consequently its inhibition early in critical illness might be deleterious. Evidence from large nutrition trials, particularly in acute cardiac illness, is scarce. Nutrition therapy is therefore focused on avoiding iatrogenic harm. Some enteral nutrition is administered if possible and eventually temporary hypocaloric feeding is tolerated. Above all, the refeeding syndrome and other nutrition-related complications should be prevented. There is no indication for early parenteral nutrition, increased protein doses, specific amino acids, or modified lipids in critical illness.
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Casaer, Michael P., and Greet Van den Berghe. Nutrition support in acute cardiac care. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199687039.003.0032_update_002.
Full textAbstract:
Malnutrition in cardiac and critical illness is associated with a compromised clinical outcome. The aim of nutrition therapy is to prevent these complications and particularly to attenuate lean tissue wasting and the loss of muscle force and of physical function. During the last decade, several well-powered randomized controlled nutrition trials have been performed. Their results challenge the existing nutrition practices in critically ill patients. Enhancing the nutritional intake and the administration of specialized formulations failed to evoke clinical benefit. Some interventions even provoked an increased mortality or a delayed recovery. These unexpected new findings might be, in part, caused by an important leap forward in the methodological quality in the recent trials. Perhaps reversing early catabolism in the critically ill patient by nutrition or anabolic interventions is impossible or even inappropriate. Nutrients effectively suppress the catabolic intracellular autophagy pathway. But autophagy is crucial for cellular integrity and function during metabolic stress, and consequently its inhibition early in critical illness might be deleterious. Evidence from large nutrition trials, particularly in acute cardiac illness, is scarce. Nutrition therapy is therefore focused on avoiding iatrogenic harm. Some enteral nutrition is administered if possible and eventually temporary hypocaloric feeding is tolerated. Above all, the refeeding syndrome and other nutrition-related complications should be prevented. There is no indication for early parenteral nutrition, increased protein doses, specific amino acids, or modified lipids in critical illness.
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Servin, Frédérique S., and Valérie Billard. Anaesthesia for the obese patient. Edited by Philip M. Hopkins. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199642045.003.0087.
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Obesity is becoming an epidemic health problem, and the number of surgical patients with a body mass index of more than 50 kg m−2 requiring anaesthesia is increasing. Obesity is associated with physiopathological changes such as metabolic syndrome, cardiovascular disorders, or sleep apnoea syndrome, most of which improve with weight loss. Regarding pharmacokinetics, volumes of distribution are increased for both lipophilic and hydrophilic drugs. Consequently, doses should be adjusted to total body weight (propofol for maintenance, succinylcholine, vancomycin), or lean body mass (remifentanil, non-depolarizing neuromuscular blocking agent). For all drugs, titration based on monitoring of effects is recommended. To minimize recovery delays, drugs with a rapid offset of action such as remifentanil and desflurane are preferable. Poor tolerance to apnoea with early hypoxaemia and atelectasis warrant rapid sequence induction and protective ventilation. Careful positioning will prevent pressure injuries and minimize rhabdomyolysis which are frequent. Because of an increased risk of pulmonary embolism, multimodal prevention is mandatory. Regional anaesthesia, albeit technically difficult, is beneficial in obese patients to treat postoperative pain and improve rehabilitation. Maximizing the safety of anaesthesia for morbidly obese patients requires a good knowledge of the physiopathology of obesity and great attention to detail in planning and executing anaesthetic management. Even in elective surgery, many cases can be technical challenges and only a step-by-step approach to the avoidance of potential adverse events will result in the optimal outcome.
Book chapters on the topic "Lean tissue mass loss"
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Alici, Yesne, and Victoria Saltz. "Weight and Appetite Loss in Cancer." In Psycho-Oncology, edited by William S. Breitbart, 298–302. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780190097653.003.0039.
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Weight and appetite loss in cancer patients, referred to as the cancer anorexia-cachexia syndrome, is a complex, multifactorial syndrome, defined by an ongoing loss of skeletal muscle mass, with or without loss of fat mass, which cannot be fully reversed by conventional nutritional support, and may lead to progressive functional impairment. It is a hypercatabolic state in the context of chronic inflammatory response best described in the setting of cancer but can also be seen in other advanced chronic illness. Cancer cachexia occurs in approximately 50% of cancer patients, and in 80% of those with advanced cancer. It impacts adversely on function, treatment tolerability and treatment response, and health service utilization, but most importantly, dignity, sense of self, quality of life, and survival. The pathophysiology of cancer cachexia is complex and multifactorial. It is characterized by a negative protein and energy balance, driven by a variable combination of reduced food intake, increased resting energy expenditure, and net loss of lean tissue. The best approach to weight and appetite loss among cancer patients is a multimodal therapy, in which a personalized combination of pharmacologic and nonpharmacologic treatments is implemented. This chapter will provide an overview of the cancer anorexia cachexia syndrome as relevant to the practice of clinicians of all disciplines managing cancer patients.
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"Loss of Lean Body Mass." In Encyclopedia of Trauma Care, 885. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-29613-0_100927.
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"Chromium (III) in Promoting Weight Loss and Lean Body Mass." In Obesity, 359–68. CRC Press, 2007. http://dx.doi.org/10.1201/9781420005479-36.
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Zafra-Stone, Shirley, Harry Preuss, Debasis Bagchi, and Manashi Bagchi. "Chromium (III) in Promoting Weight Loss and Lean Body Mass." In Obesity, 339–47. CRC Press, 2007. http://dx.doi.org/10.1201/9781420005479.ch26.
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"Human immunodeficiency virus (HIV) infection." In Oxford Handbook of Nutrition and Dietetics, edited by Joan Webster-Gandy, Angela Madden, and Michelle Holdsworth, 745–52. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198800132.003.0031.
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Phillips, KJ, JZ Lin, LJ Minze, AA Gupte, ZZ Shi, WA Hsueh, P. Webb, and JD Baxter. "The Thyromimetic GC-1 Causes Dramatic Fat Loss While Sparing Lean Tissue by Activating Brown Fat." In Posters I, P2–9—P2–9. Endocrine Society, 2010. http://dx.doi.org/10.1210/endo-meetings.2010.part2.p1.p2-9.
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Ingram, Keith T. "Drought-Related Characteristics of Important Cereal Crops." In Monitoring and Predicting Agricultural Drought. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195162349.003.0008.
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Humans cultivate more than 200 species of plants, but this chapter reviews responses of 5 important cereal crops to drought. These crops are maize (Zea mays L.), rice (Oryza sativa L.), wheat (Triticum aestivum and Triticum turgidum L. var. durum), sorghum (Sorghum bicolor [L.] Moench), and pearl millet (Pennisetum glaucum [L.] R. Br), which provide the majority of food in the world. In general, farmers cultivate millet in the most drought-prone environments and sorghum where a short growing season is the greatest constraint to production. Some sorghum cultivars set grain in as short as 50–60 days (Roncoli et al., 2001). Rice is grown under a wide range of environments, from tropical to temperate zones, from deep water-flooded zones to nonflooded uplands. Rice productivity is limited mostly by water (IRRI, 2002). Drought limits, to a varying extent, the productivity of all of these crops. Although water is likely the most important manageable limit to food production worldwide, we should recognize that water management cannot be isolated from nutrient, crop, and pest management. Life on earth depends on green plants, which capture solar energy and store chemical energy by the process of photosynthesis. Although plants use a small amount of water in the reactions of photosynthesis and retain small amounts of water in plant tissues, as much as 99% of the water that plants take up is lost through transpiration (i.e., gaseous water transport through the stomata of leaves). Stomata, which are small pores on leaf surfaces, must open to allow carbon dioxide to enter leaf tissues for photosynthesis and plant growth, but open stomata also allow water to escape. In addition to transpiration, there are several other avenues of water loss from a crop system. Water may exit the crop system by evaporation from the soil, transpiration of weeds, deep drainage beyond the root zone, lateral flow beneath the soil surface, or runoff. We can sum the daily additions and losses of water to form a water balance equation: . . . S = G + P + I − E − T − Tw − D − L − R [2.1] . . .
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Faktor, Jakub, David R. Goodlett, and Irena Dapic. "Trends in Sample Preparation for Proteome Analysis." In Mass Spectrometry in Life Sciences and Clinical Laboratory. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95962.
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Sample preparation is a key step in proteomics, however there is no consensus in the community about the standard method for preparation of proteins from clinical samples like tissues or biofluids. In this chapter, we will discuss some important steps in sample preparation used for bottom-up proteome profiling with mass spectrometry (MS). Specifically, tissues, which are an important source of biological information, are of interest because of their availability. Tissues are most often stored as fresh frozen (FF) or formalin-fixed paraffin-embedded (FFPE). While FF tissues are more readily available, paraffin embedding has historically been routinely used for tissue preservation. However, formaldehyde induced crosslinks during FFPE tissue preservation present a challenge to the protocols used for protein retrieval. Moreover, in our view, an important aspect to consider is also the amount of material available at the start of a protocol since this is directly related to the choice of protocol in order to minimize sample loss and maximize detection of peptides by MS. This “MS sensitivity” is of special importance when working with patient samples that are unique and often available in limited amounts making optimization of methods to analyze the proteins therein important given that their molecular information can be used in a patients’ diagnosis and treatment.
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Lee, Christine U., and James F. Glockner. "Case 4.22." In Mayo Clinic Body MRI Case Review, edited by Christine U. Lee and James F. Glockner, 228–29. Oxford University Press, 2014. http://dx.doi.org/10.1093/med/9780199915705.003.0120.
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76-year-old man with weight loss and jaundice Coronal fat-suppressed 2D SSFP images (Figure 4.22.1) reveal an ill-defined mass involving the pancreatic uncinate process and completely encasing the superior mesenteric artery. Note also multiple small lymph nodes and associated soft tissue stranding adjacent to the duodenum. Axial portal venous phase postgadolinium 3D SPGR images (...
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"Human immunodeficiency virus (HIV) infection." In Oxford Handbook of Nutrition and Dietetics, edited by Joan Webster-Gandy, Angela Madden, and Michelle Holdsworth, 663–69. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199585823.003.0031.
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Introduction, nutritional goals, and assessment 664 Unintentional weight and lean tissue loss 666 Cardiovascular risk and complications associated with HIV disease and treatment 667 Additional dietary issues 668 Untreated human immunodeficiency virus (HIV) infection leads to progressive suppression of immune function, eventually rendering the body susceptible to opportunistic infections and tumours. While there is no cure, antiretroviral therapy (ART) is highly effective in suppressing HIV replication. HIV disease is now a chronic condition and causes of death in this population have shifted from traditional AIDS-related illnesses to non-AIDS (Acquired Immune Deficiency Syndrome) events, the most common being atherosclerotic cardiovascular disease, liver disease, end-stage renal disease and non-AIDS–defining malignancies. There are a diverse range of nutritional conditions associated with HIV, reflecting the complexity of the disease and pharmacological management....
Conference papers on the topic "Lean tissue mass loss"
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Maynard, Jacqueline A., Ahmad S. Arabiyat, Anna Elefante, Lucas Shearer, Eoin King, and Andrea Kwaczala. "Using Acoustic Waves to Modulate Stem Cell Growth and Differentiation." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71341.
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During spaceflight, the loss of mechanical loads due to microgravity leads to rapid bone loss, where bone deteriorates at a rate of 1–2% per month, where some astronauts can lose as much as 20% of their skeletal mass in a single expedition [NASA, 2001]. In order to prevent muscle and bone loss, long-term space flight exercise regimes are strictly implemented [Shackleford, 2004]. Current research has demonstrated that mechanical vibrations can help to maintain or improve bone mass [Chan, 2013] and reduce adiposity [Chen, 2015, Sen, 2011] when signals are applied at the appropriate frequency and amplitude. We have developed an acoustic sound chamber that can apply sound waves to stem cells grown in vitro. Characterization of the culture conditions inside the vibration chamber showed considerable variance across the culture plates where an applied acceleration of 0.6g varied at different spots in a 12-well tissue culture plate from as low as 0.47g to 0.78g. We believe the variance is caused by differences in the rigidity of the culture plates that makes the waves transmit inconsistently through the plastic. We hypothesized acoustic waves would induce osteogenic differentiation when applied to stem cells. We utilized pre-osteoblastic stem cells (MC3T3-E1-Subclone 4) to observe the effects of acoustic waves when applied at 0.3g and 0.6g, compared to non-vibrated controls. Cells were vibrated for 30 minutes a day for either 6 days (n = 24/group) or 12 days (n = 12/group). Cellular changes were characterized by assessing well-by-well cell number by a manual cell count and mineral content by Alizarin Red S staining. Differences between groups were determined using One-Way ANOVA with a post hoc test: Student’s t-test. To assess the effects of the variance across the culture plates, correlative analysis was conducted for well-by-well variation using Regression Analysis. Acoustically vibrated wells had 10x more cells after 6 days and showed more mineralization than non-vibrated wells at both 6 and 12 days. Acoustic waves have the ability to increase cell proliferation and can drive stem cell differentiation towards an osteoblastic lineage, this could lead to therapies that prevent bone loss during spaceflight.
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Dumitras, Dan C., Consuela-Elena Matei, and Doru C. A. Dutu. "Laser-induced tissue ablation described by linear mass loss model." In ALT'99 International Conference: Advanced Laser Technologies, edited by Vladimir I. Pustovoy and Vitali I. Konov. SPIE, 2000. http://dx.doi.org/10.1117/12.378153.
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Hồng, Nguyễn Dương Ánh, Đàm Hoàng Lĩnh, Lê Thị Tươi, Đỗ Thị Như Trang, Dương Thị Anh Đào, Nguyễn Thị Trung Thu, and Lê Thị Tuyết. "EFFECT OF MANGOSTEEN (Garcinia mangostana L.) PEEL EXTRACT ON WEIGHT LOSS AND ADIPOSE TISSUE MASS IN MICE." In NGHIÊN CỨU VÀ GIẢNG DẠY SINH HỌC Ở VIỆT NAM - BIOLOGICAL RESEARCH AND TEACHING IN VIETNAM. Nhà xuất bản Khoa học tự nhiên và Công nghệ, 2022. http://dx.doi.org/10.15625/vap.2022.0067.
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Diers, Olaf, Denis Schneider, Melanie Voges, Peter Weigand, and Christoph Hassa. "Investigation of Combustion Oscillations in a Lean Gas Turbine Model Combustor." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27360.
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This contribution is a continuation of ASME-GT2006-90300. While still working at atmospheric pressure, the range of operating conditions was extended to more realistic reduced mass flows to reproduce the engine pressure loss and air preheat up to 700K. The thermoacoustic behaviour of the burner was mapped over that operating range. Two different types of oscillations were observed for flames anchored at the nozzle or lifted from it. Both exhibited a frequency dependence on the Strouhal number for constant reduced mass flows. For a selected operating point with the lifted flame at a preheat temperature of 600K and a reduced mass flow of 0.3kg K0.5/(s bar), the thermoacoustic behaviour of the burner was characterised by phase locked Particle Image Velocimetry as well as phase locked OH- and OH-T- LIF measurements and correlated to the acoustic pressure signal obtained by microphones. The combined data showed pulsating combustion being supported through periodic reignition of the main flame zone by a recirculating volume of hot, OH-rich gas, the cycle time being connected to the observed frequency. The characterization of the preheated operating point was completed with a heat balance investigation quantifying the non-adiabatic combustion conditions of the uncooled combustor.
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Phillips, Jonathan A., Kanaklata Roy, Anthony N. Imbalzano, and Lawrence J. Bonassar. "Genetic Manipulation of Adhesion Protein Expression to Regulate Tissue Remodeling." In ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/bed-23153.
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Abstract Physical forces play an essential role in life. Stimulating living cells or tissues with mechanical cues can conjure a myriad of biochemical and biophysical responses. [1,2,3] It is well known that mechanical cues, such as gravity, are important in proper tissue development and maintenance. [4] Likewise, mechanical cues have proven to be essential when engineering living tissue. [5] It has been shown that giving mechanical input to engineered load-bearing tissues will often result in a product more closely resembling the native tissue. [5,6] In contrast, studies done in the microgravity environment of outer space have shown that a loss of the constant mechanical input of gravity will result in loss of tissue mass. [7,8,9] Tissue engineering in microgravity systems has also resulted in “mechanically inferior” tissue. [10] It is now know that feedback from cellular mechanoreceptors is critical for proper development, maintenance, and remodeling of tissues. Actual mechanisms and biochemical pathways involved in mechanotransduction have not been fully elucidated and are subjects of intensifying research.
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Zhou, Zhijun, Yang Wang, Weijuan Yang, Junhu Zhou, Jianzhong Liu, Zhihua Wang, and Kefa Cen. "Improving Micro Combustor Stability With External Heating." In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18047.
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Heat loss is the key factor to micro combustor stability. In this experiment, a quartz-glass micro combustor with inner diameter of 2 mm is tested with wind sweeping over its surface. The wind temperature is adjusted from 4 to 728 °C to control the combustor heat loss. According to the experimental results, the combustor stability increases with the wind temperature. Take 0.2 L/min as an example, the equivalence ratio at stability limit is 0.652–3.96 with 4 °C wind, and extends to 0.540–12.0 with 107 °C wind. Computational fluid dynamic simulation reveals that hotter wind intensifies the reaction, thus reaction temperature and OH concentration increase accordingly. Moreover, hotter wind enhances the heat recirculation, which causes shift upstream of flame. Increasing flow rates also inhibits extinction. But the quenching mode transforms from extinction to blowout, while the flow rate exceeds about 0.28 L/min. In the rich cases, hot wind with higher temperature aggravates blowout, which is opposite to the lean cases. According to the experimental phenomenon, the reaction region locates close to the inlet in the rich cases, where the flow velocity increases dramatically. Therefore, the imbalance between flow velocity and burning velocity causes blowout.
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Wood, Lisa J., Collin R. Elsea, Lillian M. Nail, Kerri A. Winters, and Brian J. Druker. "Abstract B36: Induction of IL-6 by breast cancer chemotherapy mediates loss of fat-free lean body mass in tumor-free mice by decreasing systemic IGF-1." In Abstracts: AACR International Conference on Translational Cancer Medicine--; Mar 21–24, 2010; Amsterdam, The Netherlands. American Association for Cancer Research, 2010. http://dx.doi.org/10.1158/1078-0432.tcme10-b36.
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Rajasegar, Rajavasanth, Constandinos M. Mitsingas, Eric K. Mayhew, Qili Liu, Tonghun Lee, and Jihyung Yoo. "Development and Experimental Characterization of Metal 3D-Printed Scalable Swirl Stabilized Mesoscale Burner Array." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72577.
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The development of a mesoscale burner array capable of sustaining stable, clean, and compact flames suited for a variety of applications with performance and emission characteristics comparable to that of existing large scale burners is presented. The proposed architecture offers significant improvements in flame stability, by minimizing susceptibility to extinction, while maintaining high combustion efficiency and low emission levels under ultra-lean operating conditions for a wide range of combustion power outputs. A prototype 4×4 mesoscale burner array was designed and manufactured using Direct Metal Laser Sintering process (DMLS). The combustor array operates on gaseous fuel (methane) and employs a combination of swirl and bluff body for flame stabilization. The mesoscale burner array can sustain ultra-lean flames with lean blow off limits (LBO) of around ϕ = 0.65 independent of combustor power output that ensures adequate scalability. Thermocouple measurements indicated minimal element-to-element temperature variations with measured temperatures reaching adiabatic flame temperature levels indicating reduced heat loss due to increased flame interaction. Combustion efficiencies, about 98%, were estimated using Gas Chromatography-Mass Spectrometry (GCMS) analysis of the exhaust gas. The detected levels of combined unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions were well below 0.1% by mass. Thus, the potential for an optimized mesoscale architecture which can be seamlessly scaled over a wide range of combustor power outputs capable of powering large scale gas turbines to compact portable units without any performance deterioration or loss in power to weight ratio has been successfully demonstrated.
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Tsukamoto, Kazuhiro, Kiyotaka Hiradate, Kiyohide Sakamoto, Haruaki Chiba, and Yasushi Shinkawa. "Efficiency Increase in Centrifugal Compressor With Open Impeller by Using Curvilinear Element Blade." In ASME Turbo Expo 2015: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/gt2015-43193.
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The effect of curvilinear element blade on open-type centrifugal impeller is numerically examined in this research. We compared four different open-type centrifugal impellers. Two of them were linear element blade impellers: one has a positive tangential lean to the rotation at the outlet and the other has negative tangential lean. The other two were curvilinear element blade impellers having different tangential lean profiles. Numerical simulation of steady flow was conducted in one-blade path model with inlet, impeller and vane-less diffuser regions. The simulation confirm that impellers with negative tangential lean profiles improve the stage efficiency under the flow rate at the design point and the curvilinear element blade improve the stage efficiency not only at the design point but the lower flow rate regions also. The efficiency increase at the design point is obtained not in the vane-less diffuser region but in the impeller region since the negative lean profile reduce the tip-leakage loss near the impeller outlet region. The negative tangential lean profile changes the pressure distribution in the flow passage between two impeller blades. The pressure difference between the pressure surface and the suction surface of one blade near the tip region decrease because of the pressure distribution change. Hence, the mass flow rate of the tip leakage decreases and reduces the loss generation. In addition, the reason why the stage efficiency increases under the lower flow rate conditions by using curvilinear element blade is the suppression effect of the flow separation in the vane-less diffuser. This result indicates that there is a design criteria both tangential lean angle and the inflection point of the profile from positive to negative to suppress the flow separation at the hub side in the vane-less diffuser.
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Pundle, Anamol, David G. Nicol, Philip C. Malte, and Joel D. Hiltner. "Modeling the Formation of Pollutant Emissions in Large-Bore, Lean-Burn Gas Engines." In ASME 2017 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icef2017-3577.
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This paper discusses chemical kinetic modeling used to analyze the formation of pollutant emissions in large-bore, lean-burn gas reciprocating engines. Pollutants considered are NOx, CO, HCHO, and UHC. A quasi-dimensional model, built as a chemical reactor network (CRN), is described. In this model, the flame front is treated as a perfectly stirred reactor (PSR) followed by a plug flow reactor (PFR), and reaction in the burnt gas is modeled assuming a batch reactor of constant-pressure and fixed-mass for each crank angle increment. The model treats full chemical kinetics. Engine heat loss is treated by incorporating the Woschni model into the CRN. The mass burn rate is selected so that the modeled cylinder pressure matches the experiment pressure trace. Originally, the model was developed for large, low speed, two-stoke, lean-burn engines. However, recently, the model has been formatted for the four-stroke, open-chamber, lean-burn engine. The focus of this paper is the application of the model to a four-stroke engine. This is a single-cylinder non-production variant of a heavy duty lean-burn engine of about 5 liters cylinder displacement Engine speed is 1500 RPM. Key findings of this work are the following. 1) Modeled NOx and CO are found to agree closely with emission measurements for this engine over a range of relative air-fuel ratios tested. 2) This modeling shows the importance of including N2O chemistry in the NOx calculation. For λ = 1.7, the model indicates that about 30% of the NOx emitted is formed by the N2O mechanism, with the balance from the Zeldovich mechanism. 3) The modeling shows that the CO and HCHO emissions arise from partial oxidation late in the expansion stroke as unburned charge remaining mixes into the burnt gas. 4) Model generated plots of HCHO versus CH4 emission for the four-stroke engine are in agreement with field data for large-bore, lean-burn, gas reciprocating engines. Also, recent engine tests show the correlation of UHC and CO emissions to crevice volume. These tests suggest that HCHO emissions also are affected by crevice flows through partial oxidation of UHC late in the expansion stroke.