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Impairments in balance control are inevitable following exposure to microgravity. However, the role of particular sensory system in postural disorders at different stages of the exposure to microgravity still remains unknown. We used a method called Dry Immersion (DI), as a ground-based model of microgravity, to elucidate the effects of 6-h of load-related afferent inputs on kinematic characteristics of postural corrective responses evoked by pushes to the chest of different intensities during upright standing. The structure of postural corrective responses was altered following exposure to DI, which was manifested by: (1) an increase of the ankle and knee flexion during perturbations of medium intensity, (2) the lack of the compensatory hip extension, as well as diminished knee and ankle flexion with a further increase of the perturbation intensity to submaximal level. We suggest that the lack of weight-bearing increases the reactivity of the balance control system, whereas the ability to scale the responses proportionally to the perturbation intensity decreases. Disrupted neuromuscular coordination of postural corrective responses following DI can be attributed to adaptive neural modifications on the spinal and cortical levels. The present study provides evidence that even a short-term lack of load-related afferent inputs alters kinematic patterns of postural corrective responses, and can result in decreased balance control. Because vestibular input is not primarily affected during the DI exposure, our results indicate that activity and the state of the load-related afferents play critical roles in balance control following real or simulated microgravity.

The study focused on the effects of duration of a single aerobic exercise session of moderate intensity (60% of {ie296-1}) on the activation of PGC-1α gene expression-regulating signaling kinases and the expression of the genes that regulate mitochondrial biogenesis and play a role in regulating catabolism. Nine athletes ({ie296-2} 59 mL/min/kg) cycled on a ergometer for 30, 60, and 90 min. A exercise-induced increase in PGC-1α gene expression was found to occur without activation of the kinases AMPK, p38 MAPK, and CaMKII. A comparable increase in PGC-1α gene expression was observed after 60- and 90-min exercises, while VEGFA gene expression increased only after 90-min exercise. Even 90-min exercise of the given intensity did not activate the FOXO1-E3 ubiquitin ligase pathway, nor did it increase the expression of catabolism-regulating genes.

Introduction: We investigated the effect of resist- ance exercise intensity and exercise-induced metabolic stress on the activation of anabolic signaling and expression of myo- genic genes in skeletal muscle. Methods: Ten strength-trained athletes performed high-intensity (HI, 74% of 1-repetition maxi- mum (RM)), middle-intensity (MI, 54% 1RM), or middle-intensity (54% 1RM) no-relaxation exercise (MIR). Kinase phosphoryla- tion level and myogenic gene expression in muscle samples were evaluated before, 45 min, 5 h, and 20 h after exercise. Results: The lactate concentration in MI was approximately 2- fold lower than in the 2 other sessions, and was highest in MIR. The phosphorylation level of extracellular kinase 1/2 Thr202/Tyr204 after exercise was related to metabolic stress. Metabolic stress induced a decrease in myostatin mRNA expression, whereas mechano-growth factor mRNA level depended on exercise intensity. Conclusion: This study demonstrates that both inten- sity and exercise-induced metabolic stress can be manipulated to affect muscle anabolic signaling. Muscle Nerve 000:000-000, 2014

The hypertrophic effect of strength training is known to be due to mechanical and metabolic stimuli. During exercises with the restricted blood supply of working muscles, i.e., under the conditions of intensified metabolic stress, the training effect may be achieved with much lower external loads (20% of one repetition maximum). The effects of 8 weeks of high-intensity (80–85% of one repetition maximum) strength training were compared to low-intensity (50% of one repetition maximum) training without relaxation. The high-intensity strength training resulted in higher increases in strength and size of the exercised muscles than training without relaxation. During high-intensity training, at the muscle cross section, an increase in the area occupied by type II fibers prevails; while, during training without relaxation, an increase in the area occupied by type I fibers prevails. An exercise session without relaxation leads to a more pronounced increase in the secretion of the growth hormone, insulin-like growth factor-1, and cortisol. The expression of gene regulating myogenesis (Myostatin) is changed in different ways after a high-intensity strength exercise session and after an exercise session without relaxation. Low-intensity strength training (50% of one repetition maximum) without relaxation is an efficient way for inducing increases of the strength and size of the trained muscles. This low-intensive type of training may be used in rehabilitation medicine, sports, and fitness.

The lateral stiffness and electromyogram characteristics of the resting calf flexor and extensor muscles have been studied in 18 subjects during a seven-day immersion with and without mechanical stimulation of the foot support zones. It has been shown that as early as day 1 of support deprivation, the lateral stiffness steadily decreases in the m. soleus and, in contrast, drastically increases in the m. tibialis anterior. A mechanical stimulation of the foot support zones decreases the rate and degree of the changes observed in both muscles. The tight correlation of the changes in the lateral stiffness with the muscle activity suggests a significant dependence of these changes on the electromyogram characteristics at rest.

The results of studies of influence of mechanostimulation of the soles’ support zones on the effects of micro-gravity in the motor system are presented. It was shown that mechanostimulation of the soles’ support zones in the regimen of slow and fast walking, every day during 7 days of dry immersion (DI), eliminates fully or suppresses considerably the effects of micro-gravity. Decrease of the force–velocity properties or atrophic changes in the leg extensors were not developed after exposure to simulated micro-gravity in the subjects who “walked” 20 min of each hour six times a day; the transverse stiffness was only slightly lowered and the amplitude of electromyographic activity at rest stayed unchanged. The level of orthostatic deficiency in this group was also lower than in the group without stimulation. These experimental results being in full agreement with previous studies point out to the leading role of the support deafferentation in gravitational deprivation of the tonic muscle system's activity and thus that adequate mechanostimulation of the soles’ support zones can be proposed as a countermeasure against the negative effects of weightlessness.

The paper summarizes the results of experimental studies advocating for the leading role of support afferentation in control of the functional organization of the tonic muscle system. It is shown that transition to supportless conditions is followed by a significant decline of transverse stiffness and maximal voluntary force of postural (extensor) muscles limiting their participation in locomotion and increasing involvement of phasic muscles. Mechanical stimulation of the support zones of the soles under the supportless conditions eliminates all the above-mentioned effects, including changes in transverse stiffness and maximal voluntary forces of postural muscles, and consequent loss of influence of postural muscles in the locomotor activity. It is suggested that support afferentation, facilitating (support is present) or suppressing (support is absent) the tonic motor units (MUs) activities, defines the coordination patterns of postural synergies, and ensures the optimal strategy of corrective postural responses.

Adaptation of skeletal muscles to physical training depends on intensity and duration of exercise sessions. The purpose of this study was to investigate the effect of the duration of moderately intensive single aerobic exercise session (60% V(O2max)) on the activation of signalling kinases which regulate PGC-1α gene expression and on the expression of regulatory genes of mitochondrial biogenesis and muscle catabolism. Nine athletes (V(O2max)) 59 mL/min/kg) performed 30-, 60-, and 90-min cycling sessions. An exercise-induced increase in PGC-1α gene expression was proved to occur without activation of AM PK, p38 MAPK and CAMKII. It was found that 60- and 90-min sessions result in comparable increases of PGC-lα gene expression, while VEGFA gene expression increased only after 90-min session. Even 90-min exercise did not induce the activation of FOXO1-E3 ubiquitin ligase pathway and did not result in an increase of expression of exercise-induced catabolic genes.

The results of studies of the effects of mechanostimulation of the soles’ support zones on the effects of microgravity in the motor system are presented. It was shown that mechanostimulation of the soles support zones in regimen of slow and fast walking, being used daily during 7 days dry immersion, eliminates fully or suppress considerably all the microgravity effects. In subjects in which stimulation was applied six times a day by 20 min every hour the decrease of force–velocities properties and atrophic changes in the leg extensors after the exposure to microgravity were not revealed. Their transverse stiffness was only slightly lowered and the amplitude of electromyographic activity at rest stayed unchanged. The level of orthostatic deficiency in this group was also lower than in the group without stimulation. Thus presented experimental results in full agreement with previous studies allow to conclude that support afferentation plays the leading role in gravitational deprivation of the activity of tonic muscle system and that adequate mechanostimulation of the soles support zones can be used as a countermeasures mean in weightlessness.

Hypertrophic effect of strength training is known to originate from mechanical and metabolic stimuli. During exercise with restricted blood supply ofworking muscles, that is under conditions of intensified metabolic shifts, training effect may be achieved with much lower external loads (20% of one repetition maximum (1 RM)). The aim of the study was to compare the effects of 8 wks high-intensity (80-85% MVC) strength training and low-intensity (50% 1 RM) training without relaxation. The high-intensity strength training leads to somewhat higher increments in strength and size of trained muscles than training without relaxation. During high-intensity training an increase of area occupied by type II fibers at muscle cross section prevails while during training without relaxation - an increase of area occupied by type I fibers takes place. An exercise session without relaxation leads to a more pronounced increase in secretion of growth hormone, IGF-1 and cortisol. Expression of gene regulating myogenesis (Myostatin) is changed in different ways after high-intensity strength exercise session and after exercise session without relaxation. Low-intensity strength training (50% 1 RM) without relaxation is an effective way for inducing increases of strength and size of trained muscles. This low intensive type of training may be used in restorative medicine, sports and physical culture.

The aim of the present study was to investigate the effect of acute aerobic exercise on the expression of PGC-1α transcript variants in human skeletal muscle. Seven endurance-trained athletes performed a 90-min cycling test (62% of VO2max). At resting state, the levels of N-truncated (NT)-PGC-1α and PGC-1α exon 1a-derived transcripts were significantly higher (20-fold; P0.05) than those of PGC-1α exon 1b- and 1c-derived transcripts. Acute exercise did not change the PGC-1α exon 1a-derived expression level, but it did increase the expression level of NT-PGC-1α mRNAs 6-fold, and the expression levels of PGC-1α exon 1b- and 1c-derived mRNAs200-fold (P0.05). We conclude that NT-PGC-1α transcript expression in resting muscle and after acute moderate-intensity exercise constituted a significant share of total PGC-1α expression. The exercise led to a higher level of PGC-1α expression from alternative promoters (exon 1b- and 1c-derived mRNA) than from the canonical proximal promoter (exon 1a-derived mRNA).

To characterize 1) pulmonary gas exchange, 2) pulmonary function, 3) lung fluid and tissue phospholipid content, and 4) thyroid hormone in the premature lamb (0.85 of term) after intra-amniotic administration of 100 micrograms of triiodothyronine (T3) 2 weeks before delivery.Nine fetal lambs were given 100 micrograms of intra-amniotic T3 under ultrasound guidance at 112 +/- 1 days' gestation and delivered at 126 +/- 1 days (term = 149 days). Five saline-injected animals served as controls. Arterial blood gases, pulmonary mechanics, and lung volumes were compared between groups for 1 hour after delivery. At delivery, tracheal fluid and blood was taken for T3, and thyroxine (T4) levels. Tracheal fluid and lung tissues were assayed for total phosphorus and disaturated phosphatidylcholine.Triiodothyronine-treated lambs had significantly higher mean arterial pH and lower PCO2 than controls (P.05) with a trend toward higher mean PO2. The dynamic lung compliance was increased by 54% with a 40% proportional increase in tidal volume and minute ventilation in the T3-treated group (P.05). Functional residual capacity increased 69% (P.05) without a change in specific compliance. The tracheal fluid and pulmonary phospholipids and tracheal fluid and plasma T3 and T4 levels were not different between the two groups.A single 100 micrograms dose of antenatal T3 significantly improves neonatal gas exchange and lung compliance. The improvement in lung function was not accompanied by an increase in pulmonary surfactant production. It is inferred that T3 improved lung function via accelerated structural development of the lung with an alternative possible effect on parenchymal connective tissue matrix.

The dry immersion experiment involved two groups of test volunteers. In one group, the volunteers were subjected to nothing else but immersion; in the other, foot support zones of the immersed volunteers were given daily mechanic stimulation. Evaluated were kinematics of normal locomotion during a series of test walks along rigid surface at a rate of 90 steps per a minute. The results of testing brought to the conclusion that the rates of mechanic foot stimulation applied in the experiment did not change energy expenditure in the joints; however, they moderated the amplitude of angular knee joint movements following 7 days in immersion.

Stiffness of m. soleus (Sol.) and m. tibialis anterior (TA) was evaluated in 16 volunteers during exposure to 7-days dry immersion alone and to the combination of immersion and mechanic stimulation of foot support zones. It was shown that Sol. stiffness decreased progressively starting from day-1 of immersion, whereas TA stiffness, on the contrary, made a sharp rise. Mechanic stimulation of foot support zones slowed down the rate and extent of changes in both muscles.

The objective of this study was to quantitate perfluorochemical (PFC) elimination kinetics during partial liquid ventilation (PLV) following an initial fill with or without hourly dosing. Young New Zealand rabbits were studied in two groups: Gr I (n = 6), PLV with a single dose of PFC liquid (perflubron: LiquiVent, Alliance Pharmaceutical Corp.); and Gr II (n = 5), PLV with PFC liquid and multiple hourly dosing . All rabbits were studied for 4 h, following initial instillation of a volume of PFC liquid equal to the measured gas functional residual capacity. Animals were ventilated at a constant breathing frequency (30 br/min), tidal volume (9.3+/-0.3 SE mL/kg), positive end expiratory pressure (4 cm H2O), and inspiratory time (0.30 s). PFC saturation of mixed expired gas (PFC-Sat) was assessed with a thermal conductivity analyzer, and PFC elimination was calculated from PFC-Sat, minute ventilation, and temperature of the expired gas. In GR II, PFC was supplemented hourly at a volume determined by PFC elimination calculations. The results demonstrated a decrease in PFC-sat and PFC loss with time, independent of group (P0.05). In addition, with hourly supplementation (GR II), PFC-Sat and PFC elimination over time was significantly (P0.05) greater than in animals (GR I) which did not receive additional doses. These data demonstrate that the PFC elimination rate is not constant and is related to the amount of PFC in the respiratory system. This may have occurred due to distributional differences of ventilation and PFC liquid between the single and multiple dosing groups. These findings also suggest that evaluation of PFC concentrations in expired gas may be a clinically useful index of intrapulmonary PFC distribution during PLV, and that maintained elevation of expired gas PFC saturation may guide optimal PFC dosing intervals and distribution to maximize protection against barotrauma.

Liquid-assisted ventilation (LAV) of the lung with perfluorochemical (PFC) requires a method of oxygenating and removing CO2 from the liquid. Current PFC LAV techniques consist of total liquid ventilation, PFC lavage, and partial liquid ventilation. Because PFC liquid is volatile, it may be lost from the lung or ventilator circuit in the expired gas. This study evaluated the efficiencies of two types of exchangers (spray bubbler and membrane oxygenator) with respect to CO2 elimination from the PFC liquid and prevention of the loss of PFC liquid. A multifactorial analysis of exchanger efficiency was performed with respect to liquid conservation and CO2 removal. PFC losses and relative efficiencies of two types of exchangers to eliminate CO2 from expired PFC liquid were evaluated, along with two types of PFC liquids. Gas (100% O2 at 4 and 8 L/min) and PFC liquid were circulated countercurrently through the exchangers (oxygenator and bubbler) through a temperature-controlled (25 degrees or 37 degrees C) open circuit. To evaluate effectiveness of CO2 elimination, an exchanger efficiency index (EEI) for CO2 was calculated applying mass-transfer theory to characterize gas transport down a concentration gradient where EEI equals: [PPFCCO2 out--PPFCCO2 in]/PgasCO2 in--PPFCCO2 in]. Rate of PFC loss from the circuit was calculated from mixed expired gas samples using a thermal detector analyzer. EEI and PFC loss rate were analyzed with respect to gas: PFC liquid flow ratios (analogous to the V/Q ratio). The results showed that 1) PFC loss rate and exchanger efficiency to remove CO2 increased with increasing gas: PFC liquid flow rates independent of the type of exchanger or PFC liquid; 2) PFC loss rate at any gas or liquid flow rate was greater for the bubbler than for the oxygenator; 3) the oxygenator was more efficient than the bubbler with respect to CO2 elimination; 4) although PFC loss rate increased with temperature and vapor pressure, there was little difference in the EEIs for the temperatures studied. These results 1) identify exchanger requirements necessary to maintain effective CO2 elimination up to four times normal CO2 loading conditions during LAV; 2) suggest that using a membrane oxygenator as the gas exchanger, in concert with stringent fluid temperature control, improves PFC liquid conservation and CO2 elimination relative to bubbler exchanger configurations; 3) highlight the importance of matching the exchanger type to the physiocochemical properties of the specific PFC liquid to optimize CO2 elimination while reducing PFC liquid loss by minimizing gas relative to PFC liquid flow rates. Because PFC liquid loss occurs with all current means of oxygenating and removing CO2, this study raises the importance of developing alternative, bulk-gas-flow-independent, means to recondition PFC liquids.

Practical training that readies the university graduate to deal with real life problems from the beginning of their engineering career is considered by many leading companies to be a critically important factor for future technological progress. An aggressive design project was undertaken by a unique collaboration between the Pennsylvania State University and Solar Turbines, Inc., an industrial gas turbine company. What made this project unusual was the requirement that the design effort had to be completed by students within the tight scheduling of this industry. It is becoming clear, as our students complete their formal education and leave, that the specific educational environment provided within this project to undergraduate and graduate level engineering students was effective, practical, and beneficial in terms of both educational value and practical outcome. Insights into undertaking such a project are described here.Copyright © 1999 by ASME

Evidence of surfactant inactivation by meconium has led to the use of exogenous surfactant therapy in the management of meconium aspiration syndrome (MAS). Liquid assisted ventilation has been shown to improve the cardiopulmonary function in lungs with high surface tension. We compared exogenous surfactant therapy with liquid assisted ventilation in the management of experimental acute meconium aspiration injury. Thirty-two newborn lambs were ventilated at peak inspiratory pressures of 13-16 cm H2O, positive end expiratory pressure of 3-4 cm H2O, fractional inspired oxygen concentration (FiO2) of 1.0, and a respiratory frequency range between 30 and 35 breaths/min. Baseline arterial blood gases, pulmonary function, and arterial blood pressure measurements were taken. All lambs were given 2-3 ml/kg of an unfiltered 25% meconium solution. Lambs were then randomized into either gas-ventilated meconium control, or one of three treatment groups: 1) surfactant; 2) partial liquid ventilation (PLV); or 3) total liquid ventilation (TLV) for 4 hours after meconium injury. All treated groups demonstrated a significant increase in arterial oxygenation (P0.05); surfactant and PLV-treated lambs demonstrated significantly decreased arterial PCO2 (P0.05). Compliance in all groups increased compared with injury values; compliance of the TLV group increased more than in all other treatment groups (P0.05). In addition, lung histology of the TLV group demonstrated clear, intact alveolar epithelium and homogeneously expanded alveoli, while no such improvement was evident in the other groups. These data suggest roles for both exogenous surfactant therapy and liquid assisted ventilation techniques in the management of MAS.

This pilot study attempted to uncover similarities and differences in perceptions of health care teams by the professionals who work in them and are affected by them. This study used a convenience sample of 125 health professionals from 14 disciplines to explore the types of general metaphors and sports metaphors that they apply to health care teams. Data were analyzed by gender, type of metaphor, and stated reasons for choosing a particular metaphor. Fifteen themes emerged from the analysis. In response to a question about the metaphors that they apply to teams, health professionals identified more nonsports than sports metaphors. There was no difference between males and females in the application of sports metaphors as general metaphors for teams. Also, respondents reported using different metaphors in current practice than those they had used at the end of their formal professional training. This study demonstrates that many health professionals apply unidimensional metaphors to a dynamic and complex process. The findings suggest that trainers can help team members expose and develop their metaphors to more fully encompass the complexities of the health care team.

A schematic representation of the variety of products which can be obtained by microbial conversion of cellulose is presented. Alkaline pre-treatment has been used after milling in all the experiments. Solka-floc or sugarcane bagasse was used as sources of cellulose. A cellulolytic strain of Aspergillus terreus (ATCC 30514) was cultivated in batch-, fed batch and continuous culture up to 7 liter stirred tank fermenter. The general growth characteristics were determined by growing on glucose. Results of experiments on the growth of A. terreus for production of biomass on Solka-floc or Sugarcane bagasse are given, also the ability of crude cellulases to produce sugar syrups by enzymatic hydrolysis of cellulose has been evaluated.