Journal articles: 'Force de réaction au sol'

1

Lefèvre, B., A. Thévenon, and P. Moretto. "Effets des vitesses de marche similaires et de la classification fonctionnelle de l'appui sur la variabilité de la composante verticale de la force de réaction au sol." Annales de Réadaptation et de Médecine Physique 47, no. 4 (May 2004): 164–68. http://dx.doi.org/10.1016/j.annrmp.2003.12.005.

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Roux, M., L. Baly, and P. Gorce. "L’étude des forces de réaction au sol peut-elle être un indicateur de la stabilité de la chaussure lors de la locomotion ?" Science & Sports 24, no. 1 (February 2009): 27–30. http://dx.doi.org/10.1016/j.scispo.2007.06.016.

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Ballas, Richard, Rémi Philipot, Pascal Edouard, Nicolas Peyrot, Florent Delangle, and Frédéric Farizon. "Forces de réaction au sol après chirurgie de l’hallux valgus. Comparaison des techniques de scarf et d’arthrodèse de la première articulation métatarso-phalangienne." Revue de Chirurgie Orthopédique et Traumatologique 98, no. 7 (November 2012): S331. http://dx.doi.org/10.1016/j.rcot.2012.08.145.

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Baillieul, S., A. El Fatimi, S. Nadeau, and D. Pérennou. "La composante verticale globale des forces de réaction au sol durant le passage assis-debout au décours d’un accident vasculaire cérébral (AVC) est-elle un invariant ?" Neurophysiologie Clinique/Clinical Neurophysiology 45, no. 4-5 (November 2015): 404. http://dx.doi.org/10.1016/j.neucli.2015.10.042.

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Lauber, Anne, Raymond Daveluy, Rachel Laurin, and Alain Payette. "Réplique en sol majeur." Positions 7, no. 1 (February 25, 2010): 65–67. http://dx.doi.org/10.7202/902159ar.

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En réponse à la réponse de Tousignant, les Mélodistes indépendants soutiennentqu’ils n’ont pas été compris dans ce qu’ils ont dit de Mozart et Mahler. Ilsréaffirment ce qu’ils contestent : l’absence de mélodie, la suppression destensions, la rythmique trop complexe, la dictature par une esthétique particulièreet la prise du pouvoir d’une certaine avant-garde dans les jurys. Ils réclament ledroit à la liberté d’expression dans le respect des traditions et se fientfondamentalement à la réaction du public.

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Lee, C., T. Itoh, G. Sasaki, and T. Suga. "Sol-gel derived PZT force sensor for scanning force microscopy." Materials Chemistry and Physics 44, no. 1 (April 1996): 25–29. http://dx.doi.org/10.1016/0254-0584(95)01647-d.

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7

Vezole, P. "Écrans de soutènement Interaction sol-structure, à propos de la méthode des modules de réaction." Revue Française de Géotechnique, no. 71 (1995): 31–37. http://dx.doi.org/10.1051/geotech/1995071031.

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8

Cova, Bernard, Denis Bansard, and Jean-Paul Flipo. "Le marketing de projets: de la réaction à l'anticipation." Recherche et Applications en Marketing (French Edition) 7, no. 4 (December 1992): 83–104. http://dx.doi.org/10.1177/076737019200700404.

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Ce qui est appelé « projet » dans cet article est une transaction complexe concernant un ensemble de produits, services et travaux, réalisé dans un contexte industriel (ex. construction de routes ou de barrages, aménagement urbain, construction d'un pétrolier, etc.). Dans ce domaine, les pratiques commerciales courantes entre les fournisseurs et les clients incluent la modalité d'appel d'offres. Ce processus d'achat traduit concrètement le fait que le client est l'unique force de proposition dans l'interaction initiale, laissant ainsi les fournisseurs éventuels en position uniquement réactive, à savoir la fourniture d'un devis en réponse au descriptif des travaux. Notre proposition consiste à dire que le marketing de projet ne peut exister que si le fournisseur potentiel adopte un comportement résolument anticipatif. Le présent article situe les caractéristiques du projet dans le contexte des transactions économiques générales, puis dans la perspective du concept marketing; il analyse ensuite de façon critique la littérature internationale publiée sur ce thème, et suggère enfin des perspectives marketing globales et des pistes pour des recherches ultérieures.

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Chambon, Maxence. "Une réaction – Le droit administratif au prisme foucaldien : force du discours, drame du droit." Revue interdisciplinaire d'études juridiques 79, no. 2 (2017): 93. http://dx.doi.org/10.3917/riej.079.0093.

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Hodgson, J. A., S. Wichayanuparp, M. R. Recktenwald, R. R. Roy, G. McCall, M. K. Day, D. Washburn, J. W. Fanton, I. Kozlovskaya, and V. R. Edgerton. "Circadian Force and EMG Activity in Hindlimb Muscles of Rhesus Monkeys." Journal of Neurophysiology 86, no. 3 (September 1, 2001): 1430–44. http://dx.doi.org/10.1152/jn.2001.86.3.1430.

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Continuous intramuscular electromyograms (EMGs) were recorded from the soleus (Sol), medial gastrocnemius (MG), tibialis anterior (TA), and vastus lateralis (VL) muscles of Rhesus during normal cage activity throughout 24-h periods and also during treadmill locomotion. Daily levels of MG tendon force and EMG activity were obtained from five monkeys with partial datasets from three other animals. Activity levels correlated with the light-dark cycle with peak activities in most muscles occurring between 08:00 and 10:00. The lowest levels of activity generally occurred between 22:00 and 02:00. Daily EMG integrals ranged from 19 mV/s in one TA muscle to 3339 mV/s in one Sol muscle: average values were 1245 (Sol), 90 (MG), 65 (TA), and 209 (VL) mV/s. The average Sol EMG amplitude per 24-h period was 14 μV, compared with 246 μV for a short burst of locomotion. Mean EMG amplitudes for the Sol, MG, TA, and VL during active periods were 102, 18, 20, and 33 μV, respectively. EMG amplitudes that approximated recruitment of all fibers within a muscle occurred for 5–40 s/day in all muscles. The duration of daily activation was greatest in the Sol [151 ± 45 (SE) min] and shortest in the TA (61 ± 19 min). The results show that even a “postural” muscle such as the Sol was active for only ∼9% of the day, whereas less active muscles were active for ∼4% of the day. MG tendon forces were generally very low, consistent with the MG EMG data but occasionally reached levels close to estimates of the maximum force generating potential of the muscle. The Sol and TA activities were mutually exclusive, except at very low levels, suggesting very little coactivation of these antagonistic muscles. In contrast, the MG activity usually accompanied Sol activity suggesting that the MG was rarely used in the absence of Sol activation. The results clearly demonstrate a wide range of activation levels among muscles of the same animal as well as among different animals during normal cage activity.

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11

Fitts, Robert H., Dominique Desplanches, Janell G. Romatowski, and Jeffrey J. Widrick. "Spaceflight effects on single skeletal muscle fiber function in the rhesus monkey." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 279, no. 5 (November 1, 2000): R1546—R1557. http://dx.doi.org/10.1152/ajpregu.2000.279.5.r1546.

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The purpose of this investigation was to understand how 14 days of weightlessness alters the cellular properties of individual slow- and fast-twitch muscle fibers in the rhesus monkey. The diameter of the soleus (Sol) type I, medial gastrocnemius (MG) type I, and MG type II fibers from the vivarium controls averaged 60 ± 1, 46 ± 2, and 59 ± 2 μm, respectively. Both a control 1-G capsule sit (CS) and spaceflight (SF) significantly reduced the Sol type I fiber diameter (20 and 13%, respectively) and peak force, with the latter declining from 0.48 ± 0.01 to 0.31 ± 0.02 (CS group) and 0.32 ± 0.01 mN (SF group). When the peak force was expressed as kiloNewtons per square meter (kN/m2), only the SF group showed a significant decline. This group also showed a significant 15% drop in peak fiber stiffness that suggests that fewer cross bridges were contracting in parallel. In the MG, SF but not CS depressed the type I fiber diameter and force. Additionally, SF significantly depressed absolute (mN) and relative (kN/m2) force in the fast-twitch MG fibers by 30% and 28%, respectively. The Ca2+ sensitivity of the type I fiber (Sol and MG) was significantly reduced by growth but unaltered by SF. Flight had no significant effect on the mean maximal fiber shortening velocity in any fiber type or muscle. The post-SF Sol type I fibers showed a reduced peak power and, at peak power, an elevated velocity and decreased force. In conclusion, CS and SF caused atrophy and a reduced force and power in the Sol type I fiber. However, only SF elicited atrophy and reduced force (mN) in the MG type I fiber and a decline in relative force (kN/m2) in the Sol type I and MG type II fibers.

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12

Schmitt, P. "Méthode empirique d'évaluation du coefficient de réaction du sol vis-à-vis des ouvrages de soutènement souples." Revue Française de Géotechnique, no. 71 (1995): 3–10. http://dx.doi.org/10.1051/geotech/1995071003.

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13

Panizzolo, Fausto Antonio, Andrew J. Maiorana, Louise H. Naylor, Lawrence G. Dembo, David G. Lloyd, Daniel J. Green, and Jonas Rubenson. "Muscle size explains low passive skeletal muscle force in heart failure patients." PeerJ 4 (September 15, 2016): e2447. http://dx.doi.org/10.7717/peerj.2447.

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BackgroundAlterations in skeletal muscle function and architecture have been linked to the compromised exercise capacity characterizing chronic heart failure (CHF). However, how passive skeletal muscle force is affected in CHF is not clear. Understanding passive force characteristics in CHF can help further elucidate the extent to which altered contractile properties and/or architecture might affect muscle and locomotor function. Therefore, the aim of this study was to investigate passive force in a single muscle for which non-invasive measures of muscle size and estimates of fiber force are possible, the soleus (SOL), both in CHF patients and age- and physical activity-matched control participants.MethodsPassive SOL muscle force and size were obtained by means of a novel approach combining experimental data (dynamometry, electromyography, ultrasound imaging) with a musculoskeletal model.ResultsWe found reduced passive SOL forces (∼30%) (at the same relative levels of muscle stretch) in CHF vs. healthy individuals. This difference was eliminated when force was normalized by physiological cross sectional area, indicating that reduced force output may be most strongly associated with muscle size. Nevertheless, passive force was significantly higher in CHF at a given absolute muscle length (non length-normalized) and likely explained by the shorter muscle slack lengths and optimal muscle lengths measured in CHF compared to the control participants. This later factor may lead to altered performance of the SOL in functional tasks such gait.DiscussionThese findings suggest introducing exercise rehabilitation targeting muscle hypertrophy and, specifically for the calf muscles, exercise that promotes muscle lengthening.

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Murrant, C. L., and J. K. Barclay. "Endothelial cell products alter mammalian skeletal muscle function in vitro." Canadian Journal of Physiology and Pharmacology 73, no. 6 (June 1, 1995): 736–41. http://dx.doi.org/10.1139/y95-096.

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We tested the hypothesis that endothelin and nitric oxide (NO) alter the force developed by fast-twitch and slow-twitch mammalian skeletal muscle, using a mouse skeletal muscle preparation trimmed to approximately 50% of the original diameter to decrease diffusion distances. We suspended trimmed soleus (SOL) and extensor digitorum longus (EDL) muscles in Krebs–Henseleit buffer (27 °C; pH 7.4) gassed with 95% O2 – 5% CO2. Muscles were stimulated once every 90 s for 500 ms at 50 Hz for SOL and 100 Hz for EDL. The force developed by trimmed SOL was 223.8 ± 9.1 mN/mm2 and by EDL was 247.3 ± 9.4 mN/mm2. Endothelin 1 (ET-1) had no effect on EDL but significantly accelerated the rate of decrease of developed force of SOL at concentrations of 10−10 mol/L and higher within 10 contractions. When ET-1 was removed, force returned toward control value. Endothelin 3 (ET-3) had no effect on either muscle. S-Nitroso-N-acetylpenicillamine (SNAP), a source of NO, increased developed force over time in both muscles, with a threshold of 10−6 mol/L. The effect was evident within 5 contractions in both muscles. Force remained elevated above control values after the removal of SNAP. Thus ET-1 attenuated and NO amplified mammalian skeletal muscle function.Key words: soleus, extensor digitorum longus, tetanic contractions, endothelin 1, endothelin 3, S-nitroso-N-acetylpenicillamine.

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15

Johann, F., T. Jungk, S. Lisinski, Á. Hoffmann, L. Ratke, and E. Soergel. "Sol-gel derived ferroelectric nanoparticles investigated by piezoresponse force microscopy." Applied Physics Letters 95, no. 20 (November 16, 2009): 202901. http://dx.doi.org/10.1063/1.3264052.

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16

Biesiadecki, B. J., M. A. Brotto, L. S. Brotto, L. G. Koch, S. L. Britton, T. M. Nosek, and J. P. Jin. "Rats genetically selected for low and high aerobic capacity exhibit altered soleus muscle myofilament functions." American Journal of Physiology-Cell Physiology 318, no. 2 (February 1, 2020): C422—C429. http://dx.doi.org/10.1152/ajpcell.00430.2019.

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Aerobic exercise capacity is critical to bodily health. As a model to investigate the mechanisms that determine health and disease, we employed low (LCR) and high (HCR) capacity running rat models selectively bred to concentrate the genes responsible for divergent aerobic running capacity. To investigate the skeletal muscle contribution to this innate difference in running capacity we employed an approach combining examination of the myofilament protein composition and contractile properties of the fast fiber extensor digitorum longus (EDL) and slow fiber soleus (SOL) muscles from LCR and HCR rats. Intact muscle force experiments demonstrate that SOL, but not EDL, muscles from LCR rats exhibit a three times greater decrease in fatigued force. To investigate the mechanism of this increased fatigability in the LCR SOL muscle, we determined the myofilament protein composition and functional properties. Force-Ca2+ measurements demonstrate decreased Ca2+ sensitivity of single skinned SOL muscle fibers from LCR compared with that of HCR rats. Segregating SOL fibers into fast and slow types demonstrates that the decreased Ca2+ sensitivity in LCR SOL results from a specific decrease in slow-type SOL fiber Ca2+ sensitivity such that it was similar to that of fast-type fibers. These results identify that the altered myofilament contractile properties of LCR SOL slow-type fibers result in a fast muscle type Ca2+ sensitivity and the LCR muscle phenotype. Overall our findings demonstrate alterations of the myofilament proteins could contribute to fatigability of the SOL muscle and the decreased innate aerobic running performance of LCR compared with HCR rats.

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Huang, Yen-Chih, Robert G. Dennis, and Keith Baar. "Cultured slow vs. fast skeletal muscle cells differ in physiology and responsiveness to stimulation." American Journal of Physiology-Cell Physiology 291, no. 1 (July 2006): C11—C17. http://dx.doi.org/10.1152/ajpcell.00366.2005.

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In vitro studies have used protein markers to distinguish between myogenic cells isolated from fast and slow skeletal muscles. The protein markers provide some support for the hypothesis that satellite cells from fast and slow muscles are different, but the data are equivocal. To test this hypothesis directly, three-dimensional skeletal muscle constructs were engineered from myogenic cells isolated from fast tibialis anterior (TA) and slow soleus (SOL) muscles of rats and functionality was tested. Time to peak twitch tension (TPT) and half relaxation time (RT1/2) were ∼30% slower in constructs from the SOL. The slower contraction and relaxation times for the SOL constructs resulted in left shift of the force-frequency curve compared with those from the TA. Western blot analysis showed a 60% greater quantity of fast myosin heavy chain in the TA constructs. 14 days of chronic low-frequency electrical stimulation resulted in a 15% slower TPT and a 14% slower RT1/2, but no change in absolute force production in the TA constructs. In SOL constructs, slow electrical stimulation resulted in an 80% increase in absolute force production with no change in TPT or RT1/2. The addition of cyclosporine A did not prevent the increase in force in SOL constructs after chronic low-frequency electrical stimulation, suggesting that calcineurin is not responsible for the increase in force. We conclude that myogenic cells associated with a slow muscle are imprinted to produce muscle that contracts and relaxes slowly and that calcineurin activity cannot explain the response to a slow pattern of electrical stimulation.

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Kaya, Motoshi, Tim R. Leonard, and Walter Herzog. "Premature deactivation of soleus during the propulsive phase of cat jumping." Journal of The Royal Society Interface 5, no. 21 (September 11, 2007): 415–26. http://dx.doi.org/10.1098/rsif.2007.1158.

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It has been shown that cat soleus (SOL) forces remain nearly constant despite increases in electromyography (EMG) activity for increasing speeds of locomotion, while medial gastrocnemius (MG) forces and EMG activity increase in parallel. Furthermore, during jumping, average cat SOL forces decrease, while average EMG activity increases dramatically compared with walking conditions. Finally, during rapid paw-shake movements, SOL forces and EMG activities are nearly zero. Based on these results, we hypothesized that the SOL is deactivated, despite ankle extensor requirements, if the contractile conditions limit SOL force potential severely. The purposes of this study were to (i) investigate SOL EMG activity and force as a function of its contractile conditions during jumping, (ii) test whether SOL EMG activity is associated with SOL contractile conditions, and (iii) determine the functional implications of SOL EMG activity during jumping. It was found that the SOL was prematurely deactivated in two distinct phases during the propulsive phase of jumping, in which shortening speeds approached or even exceeded the maximal speed of muscle shortening. We concluded that the SOL was prematurely deactivated to save energy because its mechanical work output approached zero, and speculated that the first phase of deactivation might be caused by a decrease in group Ia firing associated with active shortening and the second by a pre-programmed response inherent to the central pattern generator.

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O'Donovan, M. J., M. J. Pinter, R. P. Dum, and R. E. Burke. "Kinesiological studies of self- and cross-reinnervated FDL and soleus muscles in freely moving cats." Journal of Neurophysiology 54, no. 4 (October 1, 1985): 852–66. http://dx.doi.org/10.1152/jn.1985.54.4.852.

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The activity patterns in self- and cross-reinnervated flexor digitorum longus (FDL) and soleus (SOL) muscles were examined during natural movements in awake, unrestrained cats in which electromyographic (EMG) electrodes, tendon-force gauges, and muscle-length gauges had been chronically implanted under anesthesia and aseptic conditions. Kinesiological data were recorded between 13 and 22 mo after nerve surgery. Self-reinnervated FDL and SOL muscles (i.e., FDL----FDL and SOL----SOL, respectively) exhibited locomotor activity patterns that were the same as observed in normal, unoperated FDL and SOL muscles (26). FDL----FDL muscles exhibited primarily brief bursts of activity in early swing, just after the toes had left the ground, whereas SOL----SOL muscles showed bursts of activity just before and during stance. In contrast, the cross-reinnervated muscles (both SOL----FDL and FDL----SOL) that had little or no unwanted self-reinnervation showed the patterns of activity that are associated with the innervating foreign motoneurons. That is, cross-reinnervated SOL----FDL muscles were intensely active in quadrupedal standing and, during the stance phase of stepping, producing large force transients while actively lengthening. Conversely, cross-reinnervated FDL----SOL muscles were active mainly in short bursts at the onset of the swing phase of stepping, just after the foot had left the ground. There was considerable modulation of EMG and peak force output in FDL----SOL muscles with changing speed of locomotion, whereas little modulation was evident in SOL----FDL muscles. The activity patterns in self- and cross-reinnervated FDL and SOL muscles were also recorded during scratch and paw-shaking reflexes. As in locomotion, the observed patterns were in all cases consistent with those expected for the innervating motor pool rather than the innervated muscle. Muscles that had been dually reinnervated by both the original and foreign motor pools displayed activity patterns that were a mixture of the FDL and SOL activity patterns described above. The present results demonstrate that motoneuron activation patterns remain qualitatively unaltered when their motor axons reinnervate foreign muscles. In addition, the observations permit some quantitative estimates of the degree to which cross-reinnervated muscles are subjected to patterns of motoneuron activity and to conditions of mechanical loading that are markedly different from those in the self-reinnervated or normal conditions.

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Polyakov, Boris, Mikk Antsov, Sergei Vlassov, Leonid M. Dorogin, Mikk Vahtrus, Roberts Zabels, Sven Lange, and Rünno Lõhmus. "Mechanical properties of sol–gel derived SiO2 nanotubes." Beilstein Journal of Nanotechnology 5 (October 20, 2014): 1808–14. http://dx.doi.org/10.3762/bjnano.5.191.

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The mechanical properties of thick-walled SiO2 nanotubes (NTs) prepared by a sol–gel method while using Ag nanowires (NWs) as templates were measured by using different methods. In situ scanning electron microscopy (SEM) cantilever beam bending tests were carried out by using a nanomanipulator equipped with a force sensor in order to investigate plasticity and flexural response of NTs. Nanoindentation and three point bending tests of NTs were performed by atomic force microscopy (AFM) under ambient conditions. Half-suspended and three-point bending tests were processed in the framework of linear elasticity theory. Finite element method simulations were used to extract Young’s modulus values from the nanoindentation data. Finally, the Young’s moduli of SiO2 NTs measured by different methods were compared and discussed.

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Fitts, Robert H., Sue C. Bodine, Janell G. Romatowski, and Jeffrey J. Widrick. "Velocity, force, power, and Ca2+ sensitivity of fast and slow monkey skeletal muscle fibers." Journal of Applied Physiology 84, no. 5 (May 1, 1998): 1776–87. http://dx.doi.org/10.1152/jappl.1998.84.5.1776.

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In this study, we determined the contractile properties of single chemically skinned fibers prepared from the medial gastrocnemius (MG) and soleus (Sol) muscles of adult male rhesus monkeys and assessed the effects of the spaceflight living facility known as the experiment support primate facility (ESOP). Muscle biopsies were obtained 4 wk before and immediately after an 18-day ESOP sit, and fiber type was determined by immunohistochemical techniques. The MG slow type I fiber was significantly smaller than the MG type II, Sol type I, and Sol type II fibers. The ESOP sit caused a significant reduction in the diameter of type I and type I/II (hybrid) fibers of Sol and MG type II and hybrid fibers but no shift in fiber type distribution. Single-fiber peak force (mN and kN/m2) was similar between fiber types and was not significantly different from values previously reported for other species. The ESOP sit significantly reduced the force (mN) of Sol type I and MG type II fibers. This decline was entirely explained by the atrophy of these fiber types because the force per cross-sectional area (kN/m2) was not altered. Peak power of Sol and MG fast type II fiber was 5 and 8.5 times that of slow type I fiber, respectively. The ESOP sit reduced peak power by 25 and 18% in Sol type I and MG type II fibers, respectively, and, for the former fiber type, shifted the force-pCa relationship to the right, increasing the Ca2+ activation threshold and the free Ca2+concentration, eliciting half-maximal activation. The ESOP sit had no effect on the maximal shortening velocity ( V o) of any fiber type. V o of the hybrid fibers was only slightly higher than that of slow type I fibers. This result supports the hypothesis that in hybrid fibers the slow myosin heavy chain would be expected to have a disproportionately greater influence on V o.

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Minderis, Petras, Andrej Fokin, and Aivaras Ratkevičius. "HIGH GROWTH DUMMERSTORF MICE HAVE REDUCED SPECIFIC FORCE OF SLOW AND FAST TWITCH SKELETAL MUSCLE." Baltic Journal of Sport and Health Sciences 2, no. 101 (2016): 44–52. http://dx.doi.org/10.33607/bjshs.v2i101.55.

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Background. Mouse strains differ in body and skeletal muscle mass. It is commonly believed that specific force is a constant value irrespective of muscle mass. We hypothesised that excessive muscle hypertrophy might compromise force output. Methods. We studied force generating capacity and muscle mass of isolated soleus (SOL) and extensor digitorum longus (EDL) muscles in 14–15-week-old males of C57BL/6J, BEH+/+ and DUH mice (n = 7 per strain). In addition, muscles of young (4–5 weeks old, n = 7 per strain) BEH+/+ and DUH mice were also studied. Specific forces were calculated as isometric tetanic force divided by the estimated physiological cross-section area (PCSA) of the muscles. Results. DUH strain generated lower specific force (p < .01– .001) than both C57BL/6J and BEH+/+ strains in SOL (110 ± 20 vs. 146 ± 28 and 164 ± 8 mN/mm 2 , respectively) and EDL muscles (74 ± 18 vs. 101 ± 19 and 95 ± 11 mN/mm 2 , respectively). There were no differences between muscles of young and adult mice (p > .05). C57BL/6J and BEH+/+ generated similar specific force. Conclusions. Our results show that body mass is not associated with reduction in specific force of skeletal muscles in mice. It seems that age did not affect specific force either. However, the heaviest DUH mice had lower specific force in both slow twitch SOL and fast twitch EDL compared to BEH+/+ and C57BL/6J mice. It appears that DUH strain could be a useful model in studying factors limiting specific force of skeletal muscle.

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Baltusnikas, Juozas, Audrius Kilikevicius, Tomas Venckunas, Andrej Fokin, Lutz Bünger, Arimantas Lionikas, and Aivaras Ratkevicius. "Myostatin dysfunction impairs force generation in extensor digitorum longus muscle and increases exercise-induced protein efflux from extensor digitorum longus and soleus muscles." Applied Physiology, Nutrition, and Metabolism 40, no. 8 (August 2015): 817–21. http://dx.doi.org/10.1139/apnm-2014-0513.

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Myostatin dysfunction promotes muscle hypertrophy, which can complicate assessment of muscle properties. We examined force generating capacity and creatine kinase (CK) efflux from skeletal muscles of young mice before they reach adult body and muscle size. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of Berlin high (BEH) mice with dysfunctional myostatin, i.e., homozygous for inactivating myostatin mutation, and with a wild-type myostatin (BEH+/+) were studied. The muscles of BEH mice showed faster (P < 0.01) twitch and tetanus contraction times compared with BEH+/+ mice, but only EDL displayed lower (P < 0.05) specific force. SOL and EDL of age-matched but not younger BEH mice showed greater exercise-induced CK efflux compared with BEH+/+ mice. In summary, myostatin dysfunction leads to impairment in muscle force generating capacity in EDL and increases susceptibility of SOL and EDL to protein loss after exercise.

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Kastner, Richard. "Conférence Coulomb prononcée le 13 juin 2018 : « Parois de soutènement ancrées ou butonnées : l’apport des retours d’expérience organisés »." Revue Française de Géotechnique, no. 155 (2018): 1. http://dx.doi.org/10.1051/geotech/2018007.

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Cet article présente les résultats d’instrumentations et de retours d’expérience effectués sur des parois de soutènements ancrées ou butonnées, en milieu urbanisé. L’objectif de ces suivis était d’observer et de comprendre le comportement de ces ouvrages, leur interaction avec le sol environnant, et d’obtenir des données permettant d’évaluer de manière critique les différentes approches de dimensionnement. Les retours d’expérience ainsi effectués sur des tranchées couvertes et des stations des métros de Lyon et de Toulouse, complétés par une campagne sur modèle réduit, ont mis en évidence les interactions entre le terrain et ces ouvrages, et montré l’importance des effets de voûte dans la sollicitation des parois de soutènement, notamment lorsque les appuis sont passifs. Ils ont permis de cerner le domaine d’utilisation et les limites des approches de dimensionnement reposant sur l’hypothèse du coefficient de réaction, toujours largement utilisée. Ils confirment l’intérêt, pour ces ouvrages, des approches de type éléments finis tout en soulignant la nécessité d’adopter un modèle de sol capable de décrire les principaux comportements mis en jeu. Enfin, les rétro analyses ont permis de préciser les propriétés des terrains à l’échelle de ces ouvrages, en vue d’un dimensionnement plus rigoureux.

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Lee, Chengkuo, Toshihiro Itoh, and Tadatomo Suga. "Sol–gel derived PNNZT thin films for micromachined piezoelectric force sensors." Thin Solid Films 299, no. 1-2 (May 1997): 88–93. http://dx.doi.org/10.1016/s0040-6090(96)09453-9.

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26

Burt, Eddie C., Alvin C. Bailey, and Randall K. Wood. "Les effets des paramètres du sol et de fonctionnement sur les vecteurs de force des interfaces sol-pneu." Journal of Terramechanics 25, no. 1 (January 1988): 83. http://dx.doi.org/10.1016/0022-4898(88)90069-9.

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Aratow, M., R. E. Ballard, A. G. Crenshaw, J. Styf, D. E. Watenpaugh, N. J. Kahan, and A. R. Hargens. "Intramuscular pressure and electromyography as indexes of force during isokinetic exercise." Journal of Applied Physiology 74, no. 6 (June 1, 1993): 2634–40. http://dx.doi.org/10.1152/jappl.1993.74.6.2634.

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A direct method for measuring force production of specific muscles during dynamic exercise is presently unavailable. Previous studies indicate that both intramuscular pressure (IMP) and electromyography (EMG) correlate linearly with muscle contraction force during isometric exercise. The objective of this study was to compare IMP and EMG as linear assessors of muscle contraction force during dynamic exercise. IMP and surface EMG activity were recorded during concentric and eccentric isokinetic plantarflexion and dorsiflexion of the ankle joint from the tibialis anterior (TA) and soleus (SOL) muscles of nine male volunteers (28–54 yr). Ankle torque was measured using a dynamometer, and IMP was measured via catheterization. IMP exhibited better linear correlation than EMG with ankle joint torque during concentric contractions of the SOL (IMP R2 = 0.97, EMG R2 = 0.81) and the TA (IMP R2 = 0.97, EMG R2 = 0.90), as well as during eccentric contractions (SOL: IMP R2 = 0.91, EMG R2 = 0.51; TA: IMP R2 = 0.94, EMG R2 = 0.73). IMP provides a better index of muscle contraction force than EMG during concentric and eccentric exercise through the entire range of torque. IMP reflects intrinsic mechanical properties of individual muscles, such as length-tension relationships, which EMG is unable to assess.

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Schmitt, P. "Discussion : Au sujet de la variation du coefficient de réaction du sol en fonction de l’inertie des écrans de soutènement." Revue Française de Géotechnique, no. 74 (1996): 75–76. http://dx.doi.org/10.1051/geotech/1996074075.

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Пронин, И. А., И. А. Аверин, Н. Д. Якушова, А. А. Карманов, В. А. Мошников, and Е. И. Теруков. "Направленная самосборка микро- и нанопроводов оксида цинка." Письма в журнал технической физики 45, no. 12 (2019): 45. http://dx.doi.org/10.21883/pjtf.2019.12.47919.17806.

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Methods of directed self-assembly of micro- and nanorods of zinc oxide using centrifugal force have been developed in the framework of the sol-gel method. Fibrous structures of zinc oxide, previously obtained in the sol, are artificially ordered on the far periphery of the substrate by centrifuging at high angular velocities.

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Sarkar, Saswati, Shyamal Kumar Bhadra, and Sunirmal Jana. "Fabrication, characterization and water wetting behavior of mesoscale 1D/2D periodic structured silica-zirconia sol–gel thin films." RSC Advances 6, no. 52 (2016): 46048–59. http://dx.doi.org/10.1039/c6ra00380j.

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Wetzel, Petra, Tanja Kleinke, Simon Papadopoulos, and Gerolf Gros. "Inhibition of muscle carbonic anhydrase slows the Ca2+ transient in rat skeletal muscle fibers." American Journal of Physiology-Cell Physiology 283, no. 4 (October 1, 2002): C1242—C1253. http://dx.doi.org/10.1152/ajpcell.00106.2002.

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A countertransport of H+ is coupled to Ca2+ transport across the sarcoplasmic reticulum (SR) membrane. We propose that SR carbonic anhydrase (CA) accelerates the CO2-HCO[Formula: see text]reaction so that H+ ions, which are exchanged for Ca2+ ions, are produced or buffered in the SR at sufficient rates. Inhibition of this SR-CA is expected to reduce the rate of H+ fluxes, which then will retard the kinetics of Ca2+ transport. Fura 2 signals and isometric force were simultaneously recorded in fiber bundles of the soleus (SOL) and extensor digitorum longus (EDL) from rats in the absence and presence of the lipophilic CA inhibitors L-645151, chlorzolamide (CLZ), and ethoxzolamide (ETZ), as well as the hydrophilic inhibitor acetazolamide (ACTZ). Fura 2 and force signals were analyzed for time to peak (TTP), 50% decay time ( t 50), and their amplitudes. L-645151, CLZ, and ETZ significantly increased TTP of fura 2 by 10–25 ms in SOL and by 5–7 ms in EDL and TTP of force by 6–30 ms in both muscles. L-645151 and ETZ significantly prolonged t 50 of fura 2 and force by 20–55 and 40–160 ms, respectively, in SOL and EDL. L-645151, CLZ, and ETZ also increased peak force of single twitches and amplitudes of fura fluorescence ratio (R340/380) at an excitation wavelength of 340 to 380 nm. All effects of CA inhibitors on fura 2 and force signals could be reversed. ACTZ did not affect TTP, t 50, and amplitudes of fura 2 signals or force. L-645151, CLZ, and ETZ had no effects on myosin-, Ca2+-, and Na+-K+-ATPase activities, nor did they affect the amplitude and half-width of action potentials. We conclude that inhibition of SR-CA by impairing H+ countertransport is responsible for deceleration of intracellular Ca2+transients and contraction times.

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Zhang, Xin, Lei Mao, and Jing Ma. "An Investigation on Surface Sol-Gel Silica Film." Advanced Materials Research 787 (September 2013): 65–70. http://dx.doi.org/10.4028/www.scientific.net/amr.787.65.

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Ultrathin silica films were grown on polyimide substrates using surface sol-gel method and the film growth process was characterized by ellipsometry, atomic force microscopy, X-ray photoelectron spectroscopy, Fourier transformed infrared spectroscopy. The polyimide substrates were pretreated by chemical process for promoting the growth of silica film. On the modified polymide surface, the growth of silica films shows an island-like growth type, but not a lay-by-lay process. Moreover, the deposited silica films are not a strict SiO2 film.

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Xing, Tie Ling, Wei Zhang, Zhi Juan Liu, Ren Cheng Tang, and Guo Qiang Chen. "Preparation of Fe²⁺-Doped Silica Sol and its Application in Silk Modification." Journal of Nano Research 27 (March 2014): 95–101. http://dx.doi.org/10.4028/www.scientific.net/jnanor.27.95.

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Fe2+ doped silica sol was prepared using tetraethoxysilane (TEOS) as precursor, ethanol as solvent, hydrochloric acid as catalyst and aqueous solution of ferrous iron by sol-gel method under the follow condition: [TEO:n [EtO:n [H2=1:6:11, reacted at 70°C for 120 min with stirring. Through characterization of the prepared silica sol using particle size analyzer, X-ray diffraction (XRD) and UV-visible spectrum, it could be concluded that even and stable silica sol with nanosize and color was prepared. The prepared Fe2+ doped silica sol was applied in silk modification to endow silk with multifunctional properties and color. X-ray Photoelectron Spectroscopy (XPS) and atomic force microscopy (AFM) indicated that Fe2+-doped silica sol was treated onto the surface of silk fabric. The results showed that the Fe2+ doped silica sol treated silk had good flame retardance, water repellence and antistatic property. At the same time, silk fabric treated by the Fe2+-doped silica sol was also endowed with color.

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Chen, R. T., and R. A. Norwood. "Microstructural characterization of sol-gel coating on PET films." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 886–87. http://dx.doi.org/10.1017/s0424820100172164.

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Sol-gel processing has been used to control the structure of a material on a nanometer scale in preparing advanced ceramics and glasses. Film coating using the sol-gel process was also found to be a viable process technology in applications such as optical, porous, antireflection and hard coatings. In this study, organically modified silicate (Ormosil) coatings are applied to PET films for various industrial applications. Sol-gel materials are known to exhibit nanometer scale structures which havepreviously been characterized by small-angle X-ray scattering (SAXS), neutron scattering and light scattering. Imaging of the ultrafine sol-gel structures has also been performed using an ultrahigh resolution replica/TEM technique. The objective of this study was to evaluate the ultrafine structures inthe sol gel coatings using a direct imaging technique: atomic force microscopy (AFM). In addition, correlation of microstructures with processing parameters, coating density and other physical properties will be discussed.The materials evaluated are organically modified silicate coatings on PET film substrates. Refractive index measurement by the prism coupling method was used to assess density of the sol-gel coating.AFM imaging was performed on a Nanoscope III AFM (by Digital Instruments) using constant force mode. Solgel coating samples coated with a thin layer of Ft (by ion beam sputtering) were also examined by STM in order to confirm the structures observed in the contact type AFM. In addition, to compare the previous results, sol-gel powder samples were also prepared by ultrasonication followed by Pt/Au shadowing and examined using a JEOL 100CX TEM.

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Kareem Al-Khafajia, AbdulKareem AbdulHusssein, and AbdulNaser Hasan Al-Zurfy. "Visible Region Response of Cobalt Doped TiO2 via Sol Gel Technique." JOURNAL OF UNIVERSITY OF BABYLON for Pure and Applied Sciences 26, no. 8 (October 19, 2018): 240–44. http://dx.doi.org/10.29196/jubpas.v26i8.1789.

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TiO2 nanoparticles were prepared via sol-gel technique and then doped with cobalt ions to form TiO2 doped cobalt sol. Thin films were prepared from this sol using dip coating method and underwent calcination at a temperature of 550 C.The films were characterized by UV–Vis spectroscopy, X-ray diffraction (XRD), and atomic force microscopy (AFM). The UV–Vis. Absorption spectra show a redshift, which indicates that TiO2 doped cobalt will respond to the visible region of the spectrum rather than UV- region for pure TiO2.

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Sun, Yudie, Zhenzhen Han, Honglin Liu, Shengnan He, Liangbao Yang, and Jinhuai Liu. "Three-dimensional hotspots in evaporating nanoparticle sols for ultrahigh Raman scattering: solid–liquid interface effects." Nanoscale 7, no. 15 (2015): 6619–26. http://dx.doi.org/10.1039/c5nr00359h.

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Bojsen-Møller, Jens, Sidse Schwartz, Kari K. Kalliokoski, Taija Finni, and S. Peter Magnusson. "Intermuscular force transmission between human plantarflexor muscles in vivo." Journal of Applied Physiology 109, no. 6 (December 2010): 1608–18. http://dx.doi.org/10.1152/japplphysiol.01381.2009.

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The exact mechanical function of synergist muscles within a human limb in vivo is not well described. Recent studies indicate the existence of a mechanical interaction between muscle actuators that may have functional significance and further play a role for injury mechanisms. The purpose of the present study was to investigate if intermuscular force transmission occurs within and between human plantarflexor muscles in vivo. Seven subjects performed four types of either active contractile tasks or passive joint manipulations: passive knee extension, voluntary isometric plantarflexion, voluntary isometric hallux flexion, passive hallux extension, and selective percutaneous stimulation of the gastrocnemius medialis (MG). In each experiment plantar- and hallux flexion force and corresponding EMG activity were sampled. During all tasks ultrasonography was applied at proximal and distal sites to assess task-induced tissue displacement (which is assumed to represent loading) for the plantarflexor muscles [MG, soleus (SOL), and flexor hallucis longus (FHL)]. Selective MG stimulation and passive knee extension resulted in displacement of both the MG and SOL muscles. Minimal displacement of the triceps surae muscles was seen during passive hallux extension. Large interindividual differences with respect to deep plantarflexor activation during voluntary contractions were observed. The present results suggest that force may be transmitted between the triceps surae muscles in vivo, while only limited evidence was provided for the occurrence of force transfer between the triceps surae and the deeper-lying FHL.

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Zhao, Heng, Yi-Ning Wu, Miriam Hwang, Yupeng Ren, Fan Gao, Deborah Gaebler-Spira, and Li-Qun Zhang. "Changes of calf muscle-tendon biomechanical properties induced by passive-stretching and active-movement training in children with cerebral palsy." Journal of Applied Physiology 111, no. 2 (August 2011): 435–42. http://dx.doi.org/10.1152/japplphysiol.01361.2010.

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Biomechanical properties of calf muscles and Achilles tendon may be altered considerably in children with cerebral palsy (CP), contributing to childhood disability. It is unclear how muscle fascicles and tendon respond to rehabilitation and contribute to improvement of ankle-joint properties. Biomechanical properties of the calf muscle fascicles of both gastrocnemius medialis (GM) and soleus (SOL), including the fascicle length and pennation angle in seven children with CP, were evaluated using ultrasonography combined with biomechanical measurements before and after a 6-wk treatment of passive-stretching and active-movement training. The passive force contributions from the GM and SOL muscles were separated using flexed and extended knee positions, and fascicular stiffness was calculated based on the fascicular force-length relation. Biomechanical properties of the Achilles tendon, including resting length, cross-sectional area, and stiffness, were also evaluated. The 6-wk training induced elongation of muscle fascicles (SOL: 8%, P = 0.018; GM: 3%, P = 0.018), reduced pennation angle (SOL: 10%, P = 0.028; GM: 5%, P = 0.028), reduced fascicular stiffness (SOL: 17%, P = 0.128; GM: 21%, P = 0.018), decreased tendon length (6%, P = 0.018), increased Achilles tendon stiffness (32%, P = 0.018), and increased Young's modulus (20%, P = 0.018). In vivo characterizations of calf muscles and Achilles tendon mechanical properties help us better understand treatment-induced changes of calf muscle-tendon and facilitate development of more effective treatments.

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Trajano, Gabriel S., Janet L. Taylor, Lucas B. R. Orssatto, Craig R. McNulty, and Anthony J. Blazevich. "Passive muscle stretching reduces estimates of persistent inward current strength in soleus motor units." Journal of Experimental Biology 223, no. 21 (September 24, 2020): jeb229922. http://dx.doi.org/10.1242/jeb.229922.

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ABSTRACTProlonged (≥60 s) passive muscle stretching acutely reduces maximal force production at least partly through a suppression of efferent neural drive. The origin of this neural suppression has not been determined; however, some evidence suggests that reductions in the amplitude of persistent inward currents (PICs) in the motoneurons may be important. The aim of the present study was to determine whether acute passive (static) muscle stretching affects PIC strength in gastrocnemius medialis (GM) and soleus (SOL) motor units. We calculated the difference in instantaneous discharge rates at recruitment and de-recruitment (ΔF) for pairs of motor units in GM and SOL during triangular isometric plantar flexor contractions (20% maximum) both before and immediately after a 5 min control period and immediately after five 1 min passive plantar flexor stretches. After stretching, there was a significant reduction in SOL ΔF (−25.6%; 95% confidence interval, CI=−45.1% to −9.1%, P=0.002) but not GM ΔF. These data suggest passive muscle stretching can reduce the intrinsic excitability, via PICs, of SOL motor units. These findings (1) suggest that PIC strength might be reduced after passive stretching, (2) are consistent with previously established post-stretch decreases in SOL but not GM EMG amplitude during contraction, and (3) indicate that reductions in PIC strength could underpin the stretch-induced force loss.

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Yang, Su-won, Kwang-pil Jeong, and Jeong-gon Kim. "Study on Crystallization and Magnetic Property Deviation of Ni-Zn-Cu Ferrite Depending on the State of the Starting Material in the Annealing Process." Advances in Materials Science and Engineering 2017 (2017): 1–5. http://dx.doi.org/10.1155/2017/2619749.

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The spinel structure of the nanosize powder (Ni0.3Zn0.3Cu0.4Fe2O4) substituted by Ni, Zn, and Cu was fabricated by the sol-gel process. Changes in weight, crystal formation, and magnetic properties were observed by XRD, TG-DTA, VSM in the annealing process of the sol and gel. The saturation magnetization of the sol showed 54.8–58.6 emu/g at 500–800°C, and the gel showed 52.3–56.8 emu/g at 600–800°C. The coercive force of the sol decreased in the range −136 Oe to −11.4 Oe at 500–800°C, and the gel decreased in the range −95 Oe to −44 Oe at 600–800°C. Therefore, the deviation of the annealing temperature of the nanopowder fabricated in the sol process and the gel process was about 100°C.

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Goodman, Craig, Michael Patterson, and Gabriela Stephenson. "MHC-based fiber type and E-C coupling characteristics in mechanically skinned muscle fibers of the rat." American Journal of Physiology-Cell Physiology 284, no. 6 (June 1, 2003): C1448—C1459. http://dx.doi.org/10.1152/ajpcell.00569.2002.

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In this study, we investigated whether the previously established differences between fast- and slow-twitch single skeletal muscle fibers of the rat, in terms of myosin heavy chain (MHC) isoform composition and contractile function, are also detectable in excitation-contraction (E-C) coupling. We compared the contractile responsiveness of electrophoretically typed, mechanically skinned single fibers from the soleus (Sol), the extensor digitorum longus (EDL), and the white region of the sternomastoid (SM) muscle to t-system depolarization-induced activation. The quantitative parameters assessed were the amplitude of the maximum depolarization-induced force response (DIFRmax; normalized to the maximum Ca2+-activated force in that fiber) and the number of responses elicited until the force declined by 75% of DIFRmax (R-D75%). The mean DIFRmaxvalues for type IIB EDL and type IIB SM fibers were not statistically different, and both were greater than the mean DIFRmax for type I Sol fibers. The mean R-D75% for type IIB EDL fibers was greater than that for type I Sol fibers as well as type IIB SM fibers. These data suggest that E-C coupling characteristics of mechanically skinned rat single muscle fibers are related to MHC-based fiber type and the muscle of origin.

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Murrant, C. L., N. E. Woodley, and J. K. Barclay. "Effect of nitroprusside and endothelium-derived products on slow-twitch skeletal muscle function in vitro." Canadian Journal of Physiology and Pharmacology 72, no. 9 (September 1, 1994): 1089–93. http://dx.doi.org/10.1139/y94-152.

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We tested the hypothesis that the products of endothelial cells alter the force developed by skeletal muscle. Since these products have a very short half-life and are produced in a low concentration, we developed a superfused muscle preparation in which the mouse soleus (SOL) was superfused at 10.5 mL/min with Krebs–Henseleit buffer (KH) (27 °C; pH 7.4), gassed with 95% O2 – 5% CO2. To evaluate this preparation, we compared the superfused muscles with muscles submerged in a bath. All muscles were stimulated at 50 Hz for 500 ms once every 30 s. Submerged SOL developed 275 ± 15 mN/mm2, while the superfused muscles developed 271 ± 15 mN/mm2. Both submerged and superfused SOL consistently increased rest tension to a 3-mL bolus of 25 mM caffeine and decreased developed force when exposed to a 3-mL bolus of 30 mM diprotonated phosphate (pH 6.4). We then exposed superfused SOL to 3-mL bolus injections of KH, 1 μM acetylcholine, 30 mM nitroprusside (a source of nitric oxide), and the supernatant from dishes of cultured endothelial cells from rabbit aorta challenged with acetylcholine. Nitroprusside and the supernatant significantly improved force maintenance, compared with KH and acetylcholine, respectively. Since the supernatant should contain products of endothelial cells, these products appear to have a positive effect on contractile function in slow-twitch skeletal muscle that is similar to the effect of nitric oxide.Key words: superfused slow-twitch skeletal muscle, tetanic contractions, sodium nitroprusside, caffeine, inorganic phosphate, cultured endothelial cells.

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Patterson, M. F., G. M. M. Stephenson, and D. G. Stephenson. "Denervation produces different single fiber phenotypes in fast- and slow-twitch hindlimb muscles of the rat." American Journal of Physiology-Cell Physiology 291, no. 3 (September 2006): 518–28. http://dx.doi.org/10.1152/ajpcell.00013.2006.

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Using a single, mechanically skinned fiber approach, we tested the hypothesis that denervation (0 to 50 days) of skeletal muscles that do not overlap in fiber type composition [extensor digitorum longus (EDL) and soleus (SOL) muscles of Long-Evans hooded rats] leads to development of different fiber phenotypes. Denervation (50 day) was accompanied by 1) a marked increase in the proportion of hybrid IIB/D fibers (EDL) and I/IIA fibers (SOL) from 30% to >75% in both muscles, and a corresponding decrease in the proportion of pure fibers expressing only one myosin heavy chain (MHC) isoform; 2) complex muscle- and fiber-type specific changes in sarcoplasmic reticulum Ca2+-loading level at physiological pCa ∼7.1, with EDL fibers displaying more consistent changes than SOL fibers; 3) decrease by ∼50% in specific force of all fiber types; 4) decrease in sensitivity to Ca2+, particularly for SOL fibers (by ∼40%); 5) decrease in the maximum steepness of the force-pCa curves, particularly for the hybrid I/IIA SOL fibers (by ∼35%); and 6) increased occurrence of biphasic behavior with respect to Sr2+activation in SOL fibers, indicating the presence of both slow and fast troponin C isoforms. No fiber types common to the two muscles were detected at any time points ( day 7, 21, and 50) after denervation. The results provide strong evidence that not only neural factors, but also the intrinsic properties of a muscle fiber, influence the structural and functional properties of a particular muscle cell and explain important functional changes induced by denervation at both whole muscle and single cell levels.

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Kirk, A., W. Fundamenski, J.-W. Ahn, and G. Counsell. "Parallel SOL transport in MAST and JET: the impact of the mirror force." Plasma Physics and Controlled Fusion 45, no. 8 (July 7, 2003): 1445–63. http://dx.doi.org/10.1088/0741-3335/45/8/305.

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Sil, Devika, Rimlee Deb Roy, Sunirmal Jana, Rabibrata Mukherjee, Shyamal Kumar Bhadra, and Prasanta Kumar Biswas. "Patterning of sol gel thin films by capillary force assisted soft lithographic technique." Journal of Sol-Gel Science and Technology 59, no. 1 (April 26, 2011): 117–27. http://dx.doi.org/10.1007/s10971-011-2469-9.

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Rezende, Bruna Aparecida, Anderson Júnior dos Santos, Marcelo Araújo Câmara, Denilson José do Carmo, Manuel Houmard, Alessandro Roger Rodrigues, and Juan Carlos Campos Rubio. "Characterization of Ceramics Coatings Processed by Sol-Gel for Cutting Tools." Coatings 9, no. 11 (November 14, 2019): 755. http://dx.doi.org/10.3390/coatings9110755.

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In order to obtain better cutting tool performance, the coatings appear as an alternative in the machining process. The goal of the coating is to improve tribological conditions in the chip-tool and tool-workpiece interfaces. On the other hand, the use of coated tools decreases the wear of the tools. This study discusses the ceramic coatings characterization deposited in WC tools. The Al2O3 and TiO2 films present properties such as thermal stability, chemical inertia, high hardness, and good mechanical properties. These coatings were prepared by sol-gel technology. The results indicated that the multilayer coating presents better adhesion on the substrate. Moreover, lower coefficients of friction were found for the coated tools. The analysis of variance (ANOVA) was used to evaluate the influence of the cutting parameters and tool coating on the cutting force. The lower cutting force was obtained using the multilayer-coated tool. Thus, the sol-gel method appears as a novel technique to deposit coating in the WC tools to improve their performance.

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Koesterer, T. J., S. L. Dodd, and Scott Powers. "Increased antioxidant capacity does not attenuate muscle atrophy caused by unweighting." Journal of Applied Physiology 93, no. 6 (December 1, 2002): 1959–65. http://dx.doi.org/10.1152/japplphysiol.00511.2002.

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Previous studies have increased antioxidant capacity in skeletal muscle to attenuate oxidative stress and muscle atrophy during limb immobilization (Appell HJ, Duarte JAR, and Soares JMC. Int J Sports Med 18: 157–160, 1997; Kondo H, Miura M, Nakagaki I, Sasaki S, and Itokawa Y. Am J Physiol Endocrinol Metab 262: E583–E590, 1992). The purpose of this study was to determine the level of oxidative stress in muscle during hindlimb unweighting (HLU) and whether antioxidant supplementation can attenuate the atrophy and changes in contractile properties resulting from 14 days of unweighting. Muscle unweighting caused a 44% decrease in soleus (Sol) and a 30% decrease in gastrocnemius (GS) mass, a 7% decrease in body weight, and 28% decrease in tetanic force in the GS. Protein carbonyls increased by 44% in the Sol with HLU. Antioxidant supplementation did not attenuate the GS or Sol atrophy or the decrease in GS force generation during HLU. Sol and GS protein concentration was not different between groups. The GS was also subjected to three different oxidative challenges to determine whether the supplement increased the antioxidant capacity of the muscle. In all cases, muscles exhibited an increased antioxidant capacity. These data indicate that antioxidant supplementation was not an effective countermeasure to the atrophy associated with HLU.

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Caiozzo, V. J., F. Haddad, M. J. Baker, R. E. Herrick, N. Prietto, and K. M. Baldwin. "Microgravity-induced transformations of myosin isoforms and contractile properties of skeletal muscle." Journal of Applied Physiology 81, no. 1 (July 1, 1996): 123–32. http://dx.doi.org/10.1152/jappl.1996.81.1.123.

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This study examined the effects of microgravity (14 days) on 1) the contractile properties of the soleus (Sol), an antigravity skeletal muscle; and 2) the myosin heavy chain (MHC) protein and mRNA isoform content of the Sol, vastus intermedius (VI), plantaris (Plan), and tibialis anterior (TA) muscles. The force-velocity relationships of the flight Sol muscles had a significant reduction in maximal isometric tension (-37%) and a corresponding increase in maximal shortening velocity (+20%). Additionally, the force-frequency relationship of the flight Sol muscles was shifted to the right of the ground-based control group. Microgravity had the greatest effect on muscle fiber composition in the Sol muscle, with a reduction in slow muscle fibers and a corresponding increase in muscle fibers categorized as hybrid fibers. The estimated absolute MHC isoform content was altered to the greatest extent in the Sol and VI muscles, with significant decreases and elevations in the slow type I and fast type IIX MHC protein isoforms, respectively. Consistent with the protein data, both the flight Sol and VI muscles exhibited significant elevations in the fast type IIX MHC mRNA isoform. In contrast, however, the flight Plan and TA groups had significant increases in the fast type IIB MHC mRNA isoform content without corresponding changes at the protein level. The results of this study suggest that spaceflight of even short duration produces important changes in the contractile properties of antigravity skeletal muscle. These changes are mediated by alterations in MHC phenotype and reductions in muscle mass. In some instances, the alterations in MHC mRNA isoform content seemed to be uncoupled from those occurring at the protein level. This apparent uncoupling between mRNA and protein expression demonstrates that the effects of microgravity must be better understood at the transcriptional, translational, and post-translational levels.

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Huyghues-Despointes, Clotilde M. J. I., Timothy C. Cope, and T. Richard Nichols. "Intrinsic Properties and Reflex Compensation in Reinnervated Triceps Surae Muscles of the Cat: Effect of Activation Level." Journal of Neurophysiology 90, no. 3 (September 2003): 1537–46. http://dx.doi.org/10.1152/jn.00718.2002.

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The manner in which activation levels influence intrinsic muscular properties and contributions of the stretch reflex were studied in homogeneous soleus (SOL) and heterogeneous gastrocnemius (G) muscles in the decerebrate cat. Intrinsic mechanical properties were represented by the initial stiffness of the muscle, measured prior to reflex action, and by the tendency of the muscle to yield during stretch in the absence of the stretch reflex. Stiffness regulation by the stretch reflex was evaluated by measuring the extent to which reflex action reduces yielding and the extent to which stiffness depends on background force. Intrinsic mechanical properties were measured in muscles deprived of effective autogenic reflexes using the method of muscular reinnervation. Reinnervated muscles were recruited to force levels comparable to those achieved during natural locomotion. As force declined during crossed-extension reflexes in reinnervated and intact muscles, initial stiffness declined according to similar convex trajectories. The data did not support the hypothesis that, for a given force level, initial stiffness is greatest in populations of predominantly type I motor units. Incremental stiffness (Δ f/Δ l) of both G and SOL increased in the presence of the stretch reflex. Yielding of SOL (ratio of incremental to initial stiffness) substantially decreased in the presence of the stretch reflex over the full range of forces. In reflexive G, yielding significantly decreased for low to intermediate forces, whereas at higher forces, yielding was similar irrespective of the presence or absence of the stretch reflex. The stretch reflex regulates stiffness in both homogeneous and heterogeneous muscles.

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Wu, Li, Wei Xing Deng, Jin Wen Peng, Xiao Dan Lin, and Wen Shi Ma. "Studies on Surface Morphology of Water-Based Silicone Rubber/Silica Sol Hybrid Coatings by Atomic Force Microscopy." Advanced Materials Research 557-559 (July 2012): 1928–32. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.1928.

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Hybrid coatings had been prepared with water-based silicone rubber, silica sol and curing agents. This material has strong adhesion and coating properties to wood, glass, metal, ceramic, brick etc. The hybrid coatings were analyzed by atomic force microscopy (AFM). The results show that different curing agents play a key role in surface morphology of hybrid coating. Methyltris-(methylethylketoxime)silane（MOS）cured hybrid coating looks smooth and flat. When the concentration of curing agent was 3.0 wt%, the surface roughness of 20 wt% silica sol hybrid coating was only 47.2 nm. At the same conditions, 3-triethoxysilylpropylamine (APTES) cured hybrid coating displays cluster structure and the surface roughness of hybrid coating could reach 368 nm in height. With the increase of the concentration of APTES, the cluster structure becomes more obvious and the surface roughness also increases gradually. When the concentration of silica sol is increased from 15 to 30 wt%, with 3.0 wt% APTES as curing agent, the surface roughness of the hybrid coating increases from 312 to 511 nm, respectively.

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Journal articles on the topic 'Force de réaction au sol'

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