Dissertations / Theses on the topic 'Oscillating modulation of the pressure'

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. Національний технічний університет "Харківський політехнічний інститут". – Харків, 2017. З метою розширення області застосування АБС за рахунок зниження вартості модулятора тиску досліджено процес осциляційної модуляції тиску. Запропоновано конструкцію осциляційного модулятора, який задовольняє всі висунуті до нього вимоги, та доведено можливість його застосування в якості виконавчого елемента у складі дуальних адаптивних гальмівних системах. Порівняльний аналіз відомих способів модуляції тиску в гідравлічному гальмівному приводі показав, що тільки спосіб осциляційної модуляції не вимагає для своєї реалізації дорогих конструктивних елементів (електромагнітних клапанів, насосів, що підкачують, крокових електродвигунів і т.п.), що дозволяє знизити вартість модуляторів при їх застосуванні. Моделювання процесу осциляційної модуляції та лабораторні випробування осциляційного модулятора показали: – принципову можливість осциляційної модуляції у всьому необхідному діапазоні зміни тиску від 0 до 10 МПа; – працездатність запропонованої конструкції модулятора і його відповідність усім пред’явленим до модулятору АБС вимогам. Дослідження роботи осциляційного модулятора у складі дуальної адаптивної гальмівної системи, виконані шляхом моделювання процесу гальмування автомобіля при різних станах дорожньої поверхні та режимах руху підтвердили, що застосування осциляційного модулятора не погіршують показники ефективності гальмування, стійкості і керованості у порівнянні з відомими.
The dissertation on competition of a scientific degree of candidate of technical sciences, speciality 05.22.02 – cars and tractors. National technical university "Kharkiv polytechnic institute". – Kharkiv, 2017. With the of expanding the field of application of anti-block system by reducing the value of the pressure modulator investigated the process of the oscillating modulation of the pressure. The proposed design of the oscillating modulator that meets all applicable requirements and proved the possibility of its use as an clement in the composition of the dual adaptive brake systems. Comparative analysis of the known methods of modulation of the pressure in the hydraulic brake drive showed that the only way of oscillating modulation does not require expensive structural elements (solenoid valves, booster pumps, stepper motors, etc.) that can reduce the cost of modulators in its application. Modeling of oscillating modulation process and laboratory tests of oscillating modulator showed: – principle possibility of oscillating modulation in all the required range of pressure changes from 0 to 10 МПА; – the efficiency of the proposed design of the modulator and its compliance with all requirements to the anti-block system modulator. Research work of oscillating modulator comprising a dual adaptive brake system, made by modeling the process of deceleration of the vehicle under different conditions of road surface and driving conditions confirmed that the application of an oscillating modulator does not degrade the braking efficiency, stability and controllability with the known.

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. Національний технічний університет "Харківський політехнічний інститут". – Харків, 2017. З метою розширення області застосування АБС за рахунок зниження вартості модулятора тиску досліджено процес осциляційної модуляції тиску. Запропоновано конструкцію осциляційного модулятора, який задовольняє всі висунуті до нього вимоги, та доведено можливість його застосування в якості виконавчого елемента у складі дуальних адаптивних гальмівних системах. Порівняльний аналіз відомих способів модуляції тиску в гідравлічному гальмівному приводі показав, що тільки спосіб осциляційної модуляції не вимагає для своєї реалізації дорогих конструктивних елементів (електромагнітних клапанів, насосів, що підкачують, крокових електродвигунів і т.п.), що дозволяє знизити вартість модуляторів при їх застосуванні. Моделювання процесу осциляційної модуляції та лабораторні випробування осциляційного модулятора показали: – принципову можливість осциляційної модуляції у всьому необхідному діапазоні зміни тиску від 0 до 10 МПа; – працездатність запропонованої конструкції модулятора і його відповідність усім пред’явленим до модулятору АБС вимогам. Дослідження роботи осциляційного модулятора у складі дуальної адаптивної гальмівної системи, виконані шляхом моделювання процесу гальмування автомобіля при різних станах дорожньої поверхні та режимах руху підтвердили, що застосування осциляційного модулятора не погіршують показники ефективності гальмування, стійкості і керованості у порівнянні з відомими.
The dissertation on competition of a scientific degree of candidate of technical sciences, speciality 05.22.02 – cars and tractors. National technical university "Kharkiv polytechnic institute". – Kharkiv, 2017. With the of expanding the field of application of anti-block system by reducing the value of the pressure modulator investigated the process of the oscillating modulation of the pressure. The proposed design of the oscillating modulator that meets all applicable requirements and proved the possibility of its use as an clement in the composition of the dual adaptive brake systems. Comparative analysis of the known methods of modulation of the pressure in the hydraulic brake drive showed that the only way of oscillating modulation does not require expensive structural elements (solenoid valves, booster pumps, stepper motors, etc.) that can reduce the cost of modulators in its application. Modeling of oscillating modulation process and laboratory tests of oscillating modulator showed: – principle possibility of oscillating modulation in all the required range of pressure changes from 0 to 10 МПА; – the efficiency of the proposed design of the modulator and its compliance with all requirements to the anti-block system modulator. Research work of oscillating modulator comprising a dual adaptive brake system, made by modeling the process of deceleration of the vehicle under different conditions of road surface and driving conditions confirmed that the application of an oscillating modulator does not degrade the braking efficiency, stability and controllability with the known.

Ces travaux de thèse portent sur l’instabilité paramétrique survenant dans les cavités optiques fibrées passives en anneau, induite par une modulation longitudinale de la dispersion chromatique. Dans les cavités optiques, le processus d’instabilité modulationnelle est connu pour être susceptible de déstabiliser l’état stationnaire et de le transformer en un train stable d’impulsions. Nous décrivons dans ce travail comment une variation longitudinale de la dispersion à l’intérieur de la cavité enrichie la dynamique de ce type de dispositif en engendrant un régime d’instabilité paramétrique. Nous détaillons l’étude théorique de ce nouveau mécanisme ce qui nous permet d’en identifier les signatures spectrales et temporelles, parmi lesquels, la génération de multiples pics de résonances dans le spectre optique et l’apparition d’une dynamique de doublement de période dans le domaine temporel. Nous avons réalisé de tels résonateurs afin de confirmer expérimentalement nos prédictions. Le modèle que nous avons retenu consiste à réaliser un anneau en soudant entre elles des fibres uniformes présentant des dispersions différentes. En terme de résultats, nous avons tout d’abord observé pour la première fois l’apparition des instabilités modulationnelle et paramétrique dans un même système, pour ensuite s’intéresser à leur dynamique. Cette dernière est accessible grâce à des méthodes de détection en temps réel à la fois spectrale et temporelle. Nous avons ainsi pu observer avec une précision remarquable l’émergence des instabilités, le doublement de période associé au régime paramétrique ainsi que l’apparition d’un nombre record de résonances paramétriques dans notre système
This thesis work deals with the parametric instability occurring in passive optical fiber-ring cavities, which is induced by a longitudinal modulation of the chromatic dispersion. In optical cavities, the modulation instability process is known to potentially destabilize the stationary state and turn it into a stable train of pulses. We describe in this work how a longitudinal variation of the dispersion inside the cavity enriches the dynamics of this type of device by entailing a regime of parametric instability. We detail the theoretical study of this new mechanism, which allows us to identify its spectral and temporal signatures, among which, the generation of multiple resonance peaks in the optical spectrum and the appearance of a period doubling dynamics in the time domain. We have realized such resonators in order to confirm experimentally our predictions. The model we have chosen simply consists in building a ring by splicing together uniform fibers characterized by different dispersions. In terms of results, we first observed the emergence of both modulational and parametric instabilities in the same system, before investigating their dynamics. The latter is accessible thanks to real-time spectral and temporal detection methods. We thus observed with remarkable precision the emergence of the instabilities, the period doubling associated to the parametric regime and the appearance of a record number of parametric resonances in our system

An investigation into performance improvements to the modulator stage of a class-D amplifier is conducted in this thesis. Two of the standard topologies, namely class-D open-loop pulse-width modulation (PWM), and the improved self-oscillating feedback system are benchmarked against a topology which includes both a hysteretic comparator in a feedback loop and triangle wave injection. Circuit performance is analyzed by comparing how the triangle injection circuit handles known issues with open-loop and self-oscillating circuits. Using this analysis, it is shown that the triangle injection topology offers an improved power supply rejection ratio relative to open-loop PWM and reduces distortion generated by frequency modulation characteristic of the self-oscillating topology.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1992.
Vita.
Includes bibliographical references (leaves 99-101).
by Alexander Konstantinos Tziranis.
M.S.

Separating oscillating and pulsating flows in an internal adverse pressure gradient geometry are studied experimentally. Simultaneous velocity-pressure measurements demonstrate that the minor losses associated with oscillating flow in an adverse pressure gradient geometry can be smaller or larger than for steady flow. Separation is found to begin high in the diffuser and propagate downward. Flows are able to remain attached further into the diffuser with larger Reynolds numbers, larger stroke lengths, and smaller diffuser angles. The extent of separation grows with Lo/h. The minor losses grow with increasing displacement amplitude in the range 10 < Lo/h < 40. Losses decrease with Re in the range of 380

Piezoelectricity crystal is used in different area in industry, such as downhole oil, gas industry, and ballistics. The piezoelectricity crystals are able to create electric fields due to mechanical deformation called the direct piezoelectric effect, or create mechanical deformation due to the effect of electric field called the indirect piezoelectric effect. In this thesis, piezoelectricity effect is the core part. There are 4 parts in the frequency output pressure transducer: two crystal oscillators, phase-locked loop (PLL), mixer, frequency counter. Crystal oscillator is used to activate the piezoelectricity crystal which is made from quartz. The resonance frequency of the piezoelectricity crystal will be increased with the higher pressure applied. The signal of the resonance frequency will be transmitted to the PLL. The function of the PLL is detect the frequency change in the input signal and makes the output of the PLL has the same frequency and same phase with the input signal. The output of the PLL will be transmitted to a Mixer. The mixer has two inputs and one output. One input signal is from the pressure crystal oscillator and another one is from the reference crystal oscillator. The frequency difference of the two signal will transmitted to the frequency counter from the output of the mixer. Thus, the frequency output pressure transducer with a frequency counter is a portable device which is able to measure the pressure without oscilloscope or computer.

The running of gas turbines with low emissions causes high pressure pulsations to arise in the combustion chamber. These pulsations are high amplitude sound vibrations. At some frequencies these are harmful to the gas turbine. Hence these pulsations are monitored to avoid operating conditions where pulsations are specifically harmful. It is necessary to expose the system of known pulsations to verify the functionality of the monitoring process.

This report describes the development of a generator of pressure pulsations to verify the monitoring system. The output should be of harmonic form with a frequency of greater than 160 Hz and 15 mbar in amplitude. To begin with, a few alternatives to a pulsation generator are described. In light of studies of these possibilities the alternative based on a roller bearing is selected. This is considered as one of the easier alternatives to design.

An existing generator of pressure pulsations has been analyzed. The calculations from this analysis supported the construction of the new device. The new generator far exceeded the specification regarding frequency, amplitude and harmonics of the pulsations. With a few modifications, such as encapsulation, the pulsation generator will be ready for usage. It could then serve as a mobile device for the inspection of the pulsation monitoring system. Possibly the device could be equipped with a faster and stronger motor. This would permit the device to be used for the calibration of pulsation monitoring sensors.

The Na/K pumps are essential for living system and widely expressed in all eukaryotic cell membranes. By actively transporting sodium ions out of and potassium ions into the plasma membrane, Na/K pumps creates both an electrical and a chemical gradient across the plasma membrane, which are crucial for maintaining membrane potential, cell volume, and secondary active transporting of other solutes, etc. Previously, oscillating electric field with a frequency close to the mean physiological turnover rate was used to synchronize and modulate the Na/K pump molecules. Results showed that the turnover rate of Na/K pumps can be accelerated by folds. However, this what we called first generation synchronization modulation (SM) technique can only synchronize sodium and potassium translocations into their corresponding half cycles. The detailed location of each sodium extrusion and potassium intrusion can not be determined. As a result, the synchronized pumps were uniformly distributed, generating steady-state macroscopic currents. Based on these studies, Dr.Chen developed a new generation synchronization modulation technique. The waveform of original SM by adding an overshoot pulse at the end of each half cycle. This overshoot pulse has a function of energy barrier which will force all of the Na/K pumps into the same state in the pumping cycle until the membrane polarity change. As a result, Na/K pump molecules are not only synchronized into half cycles of oscillating electric field, but individual steps of the pumping cycle. Accordingly, transient pump currents or so called 'pre-steady state' pump currents are generated, from which some detailed information abut the mechanism of Na/K pumps can be dissected. In this dissertation, we firstly characterized the synchronized pump currents by modified SM. The results showed that transient currents were induced at the beginning of each half cycle as expected. The ratio between positive and negative transient currents was close to 3:2, stoichiometric number of Na/K pump. Moreover, the transient currents were significantly reduced in the presence of ouabain in a time dependent manner. In addition, by gradually increasing the frequency of SM electric field in a step-wise fashion, the synchronized pump current can be modulated to the corresponding level. Next,we utilized this technique to study some detailed mechanisms of Na/K pump, including single channel configuration in transmembrane domain and extracellular D2O effect on the turnover rate. Lastly, we extended our study to applications of this new technique and found that the modified Synchronization Modulation technique can significantly hyperpolarize the membrane potential of skeletal muscle fiber in both physiological and high potasssium conditions. During intensive exercise, the interstitial potassium ions are accumulated and temporarily reach a high level, which will attenuate the contraction force and induce muscle fatigue. Na/K pumps are crucial in the maintenance of skeletal muscle excitability and contractility by restoring the Na and K concentration gradients. By accelerating the turnover rate of Na/K pumps, SM can efficiently re-establish the membrane potential and enhance skeletal muscle contractivity, which unleashes its potential in improving certain pathological conditions, such as exercise-induced hyperkalemia.

Thesis (M.S.)--University of Missouri-Columbia, 2006.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 22, 2009) Includes bibliographical references.

Crohn’s disease is a chronic inflammatory bowel disease with unknown origin. This study investigates the combined use of surgery and immuno modulation in Crohn’s disease. The outcome of medication and surgery in 371 operations on 237 patients between 1989 and 2006 were evaluated. Moreover the effects of prednisolone, azathioprine and infliximab on the healing of colo-colonic anastomosis in 84 mice with or without colitis were evaluated. The use of thiopurines after abdominal surgery in selected cases of severe Crohn’s disease was found to prolong the time to clinical relapse of the disease from 24 to 53 months. Patients on postoperative maintenance therapy with azathioprine had a decreased symptomatic load over time and needed fewer steroid courses. The use of thiopurines was found to be a risk factor of anastomotic complications in abdominal surgery for Crohn’s disease together with pre-operative intra-abdominal sepsis and colo-colonic anastomosis. The risk for anastomotic complications increased from 4 % in those without any of these risk factors to 13 % in those with any one and 24 % if two or three risk factors were present. In patients with two or more of these, or previously established, risk factors prior to surgery one should consider refraining from anastomosis or doing a proximal diverting stoma. Another possibility is to use a split stoma in which both ends of a future delayed anastomosis are brought out in the same ostomy hole of the abdominal wall. This method was found to significantly decrease the number of risk factors prior to the actual anastomosis as well as decreasing the risk of anastomotic complications, without increasing the number of operations or the time spent in hospital. In the animal model all three medications had an ameliorating effect on the colitis compared with placebo. Only prednisolone was found to interfere with the healing of the colo-colonic anastomoses with significantly decreased bursting pressure compared with placebo as well as azathioprine and infliximab. The association between azathioprine therapy and anastomotic complications may be due to a subgroup of patients with a more severe form of the disease who have an increased risk of such complications and also are more prone to receive intense pharmacological therapy.
Crohns sjukdom är en kronisk inflammatorisk tarmsjukdom av oklar orsak. Huvudsyftet med denna avhandling var att undersöka den kombinerade behandlingen med kirurgi och immunhämmare vid Crohns sjukdom. Utfallet av medicinsk och kirurgisk behandling vid 371 operationer på 237 patienter mellan 1989 och 2006 utvärderades. Därutöver studerades effekterna av kortison, immunhämmare och behandling med inflammationsdämpande antikroppar på läkning av tjocktarms-skarv på 84 möss med eller utan inflammation i tarmen. Vid utvalda fall med svårare form av Crohns sjukdom visade sig förebyggande behandling med immunhämmare efter kirurgi förlänga tiden till återfall av symptom från 24 till 53 månader. Patienter med immunhämmare som underhållsbehandling hade också minskade symptom under uppföljningstiden med ett minskat behov av kortison. Immunhämmande behandling inför kirurgi visade sig, liksom pågående infektion i bukhålan och sydd skarv på tjocktarmen, vara en riskfaktor för att drabbas av komplikationer vid bukkirurgi på grund av Crohns sjukdom. Risken för infektionskomplikationer i bukhålan ökade från 4 % hos dem utan någon av dessa riskfaktorer till 13 % hos dem med någon och 24 % hos dem med två eller tre riskfaktorer inför operationen. Hos patienter med två eller fler kända riskfaktorer bör man överväga att avstå från att sy en skarv på tarmen vid kirurgi eller möjligen skydda skarven med en avlastande stomi. Ett alternativ till detta är att anlägga en delad stomi där bägge ändarna av den framtida skarven tas ut genom en och samma stomiöppning i bukväggen. Denna metod med en fördröjd skarv på tarmen visade sig minska antalet kirurgiska riskfaktorer inför själva skarvningen och dessutom minska risken för tidiga infektiösa komplikationer i bukhålan, utan att vare sig öka antalet kirurgiska ingrepp eller förlänga vårdtiden på sjukhus. I en djurmodell visade sig alla tre läkemedlen ha en lindrande effekt på tarminflammation jämfört med placebo. Endast kortison visade sig påverka läkningen negativt med en sänkning av bristningstrycket i den sydda skarven på tjocktarmen, jämfört med placebo såväl som med immunhämmare och antikropps-behandling. Kopplingen mellan immunhämmare och komplikationer efter sydda skarvar på tarmen behöver alltså inte vara en direkt läkemedelseffekt. Orsaken kan istället vara att en undergrupp av Crohnpatienter har en svårare sjukdomsform som ger både ökad komplikationsrisk och större behov av intensiv medicinsk behandling.

Swallowing impairment or dysphagia can be a consequence of several neurological and anatomical disorders such as stroke, Parkinson’s diseases, and head and neck cancer. Management of patients with dysphagia often involves diet modification, sensory stimulation, and exercise programme with the primary goal being safe swallowing to maintain nutrition. The aim of this project was to evaluate the effects of lemon odour and tastant on swallowing behaviour in healthy young adults. Specifically, the neural excitability and biomechanical characteristics of swallowing were measured in two studies. Neural excitability was evaluated by measuring motor-evoked potentials (MEPs) from the submental muscles which were evoked by transcranial magnetic stimulation (TMS) of the motor cortex. Biomechanical characteristics were evaluated through measures of submental muscle contraction, pressure changes in the oral cavity and pharynx, and the dynamics of the upper oesophageal sphincter (UES). Two groups of volunteers (16 in each group) participated in two separate studies. In the MEP study, 25% and 100% concentrations of lemon concentrate were presented separately as olfactory and gustatory stimuli. The four stimuli were randomly presented in four separate sessions. The olfactory stimulus was nebulized and presented via nasal cannula. Filter paper strips impregnated with the lemon concentrate placed on the tongue served as the gustatory stimulus. Tap water was used as control. TMS-evoked MEPs were measured at baseline, during control condition, during stimulation, immediately poststimulation, and at 30-, 60-, and 90-min poststimulation. Experiments were repeated using the combination of odour and tastant concentration that most significantly influenced the MEP. The biomechanical study used (a) surface electromyography (sEMG) to record contraction of the submental muscles, (b) lingual array with pressure transducers to record glossopalatal pressures, and (c) pharyngeal manometry to record pressures in the pharynx and the UES. Similar methods of presenting the stimuli were used to randomly present the 25% and 100% concentrations of lemon odour and tastant. All data were recorded concurrently during stimulation. The concentration of odour and tastant that produced the largest submental sEMG amplitude was selected for presentation of combined stimulation. Data were then recorded during combined stimulation and at 30-, 60-, and 90-min poststimulation. Results from the MEP study showed increased MEP amplitude at 30-, 60-, and 90-min poststimulation during swallowing compared to baseline, but only for the combined stimulation. Poststimulation results from the biomechanical study showed decreased middle glossopalatal pressure at 30 min and decreased anterior and middle glossopalatal contact duration at 60 min. No poststimulation changes were found in sEMG and pharyngeal manometry measures. During combined odour and tastant stimulation, there were increased pressure and contact duration at the anterior glossopalatal contact and decreased hypopharyngeal pressure. Generally, these changes correspond to increased efficiency of swallowing. In conclusion, these are the first studies to have measured the effects of flavour on neural excitability and biomechanics of swallowing and the first to have shown changes in MEP and several biomechanical characteristics of swallowing following flavour stimulation. These changes were present poststimulation, suggesting mechanisms of neural plasticity that may underlie potential value in the rehabilitation of patients with dysphagia.

Research suggests hypertension is associated with reduced somatosensory perception. Further, natural fluctuations in blood pressure (BP) across the cardiac cycle have been shown to modulate nociceptive responding, pain and tactile sensitivity, suggesting that arterial baroreceptors may be important moderators of somatosensation. This thesis further examined the influence of natural fluctuations in BP, and thus baroreceptor activity, across the cardiac cycle on electrocutaneous pain and tactile sensory thresholds and pain-related evoked potentials (PREPs) in normotensive individuals. Study 1 found pain thresholds were higher, i.e. pain was reduced, during systole compared to diastole. Further analysis revealed only participants with low-normal systolic BP displayed this cardiac cycle modulation, suggesting tonic BP may moderate cardiac cycle-related pain modulation. In the second study, tactile sensory thresholds did not vary across the cardiac cycle. However, when participants were split into high-normal and low-normal BP groups, interactions between BP and tactile sensory thresholds across the cardiac cycle were revealed. This finding suggests tonic BP may be an important factor determining the cardiac cycle modulation of tactile sensation. Study 3 found no variation in the N2 or P2 peak amplitudes, or N2-P2 peak-to-peak amplitudes across the cardiac cycle at scalp recording sites Cz, C3, or C4. Furthermore, BP median split analyses revealed no BP Group or interaction effect. As previous work reported a systolic dampening of PREPs, these data suggest the cardiac cycle-related modulation of PREPs may not be as robust as other measures of pain such as the nociceptive flexion reflex. Study 4 reported, in line with Study 3, no cardiac cycle related modulation of PREPs following stimulation of the right and left hands. However, a Hand x Scalp Electrode Site x Interval interaction was revealed for N2 peak amplitudes. These data suggest that the combination of side of stimulation and scalp recording site may be important in determining the patterning of PREPs across the cardiac cycle. Taken together, the findings of these studies suggest that pain perception, and to a lesser extent tactile sensation, are influenced by natural variations in BP across the cardiac cycle. However, modulation appears dependent on tonic BP. Conversely, pain-related brain activity across the cardiac cycle was not affected by tonic BP, but may be influenced by the combination of stimulation and recording sites.

All blood vessels in the microvasculature are embedded in loose connective tissue, which regulates the transport of fluid to and from tissues. The intersti-tial fluid pressure (IFP) is one of the forces that control this transport. A lowering of IFP in vivo results in an increased transport of fluid from the circulation into the underhydrated connective tissues, resulting in edema formation. During homeostasis, contractile connective tissue cells exert a tension on the connective tissue fibrous network by binding with β1 in-tegrins, thereby actively controlling IFP. During inflammation, the IFP is lowered but platelet-derived growth factor (PDGF)-BB induces an IFP nor-malization dependent on integrin αVβ3. We demonstrate that extracellular proteins from Streptococcus equi subspecies equi modulated cell-mediated and integrin αVβ3-directed collagen gel contraction in vitro. One of these proteins, the collagen- and fibronectin binding FNE, stimulated contraction by a process dependent on fibronectin synthesis. This study identified a pos-sible novel virulence mechanism for bacteria based on the ability of bacteria to modulate the edema response. Another protein, the collagen-binding pro-tein CNE, inhibited contraction and this led to the identification of sites in collagen monomers that potentially are involved in connecting αVβ3 to the collagen network. PDGF-BB and prostaglandin E1 (PGE1) stimulate and inhibit collagen gel contraction in vitro and normalize and lower IFP, respec-tively. We showed that these agents affected both similar and different sets of actin-binding proteins. PDGF-BB stimulated actin cytoskeleton dynamics whereas PGE1 inhibited processes dependent on cytoskeletal motor and adhesive functions, suggesting that these different activities may partly ex-plain the contrasting effects of PGE1 and PDGF-BB on contraction and IFP. Mutation of the phosphatidylinositol 3’-kinase (PI3K), but not phospholipase C (PLC)γ activation site, rendered cells unable to respond to PDGF-BB in contraction and in activation of the actin binding and severing protein cofilin. Ability to activate cofilin after PDGF-BB stimulation correlated with ability to respond to PDGF-BB in contraction, suggesting a role for cofilin in this process downstream of PDGF receptor-activated PI3K. Many proteins can modulate contraction either by affecting the extracellular matrix and cell adhesions or by altering cytoskeletal dynamics. Knowledge on how these proteins might influence IFP is likely to be of clinical importance for treat-ment of inflammatory conditions including anaphylaxis, septic shock and also carcinoma growth.

The feeding behavior of fishes is a topic that has piqued the interests of many researchers given the dynamic and ancestral nature of aquatic prey-capture. This study examines aquatic feeding in terms of the suction and ram components of feeding in smallmouth bass, Micropterus dolomieu, and how they modulate their kinematic behavior when attacking pelagic and benthic prey. Relative to other Micropterus genera, the reduced gape in smallmouth bass suggests they may create considerable suction pressure – stronger subambient pressure pulled through a smaller opening creates greater velocity. Suction feeding is useful when feeding on benthic prey, such as crayfish. Ram feeding is utilized when capturing pelagic prey, such as goldfish, because prey swimming in the water column can be overtaken with body speed. Prey-capture experiments using high-speed cinematography and pressure transducers were conducted to determine if smallmouth bass modulate their feeding performance between pelagic and benthic prey items. Results indicate that smallmouth bass modulate their behavior to include both aspects of ram and suction feeding when presented with differing prey, utilizing greater ram when feeding in the water column and stronger suction when feeding off the substrate (MANCOVA, p

Hypertension is a risk factor for many cardiovascular and cerebrovascular diseases such as atherosclerosis and stroke. It is therefore important to understand the effect of hypertension on temporal growth and remodeling of arteries. In this study, experimental hypertension was induced in the mini-pig by aortic coarctation. Basilar arteries and aortas were collected for analysis over an eight week period of hypertension with specimens from normotensive animals serving as controls. Changes in mechanical properties of the basilar artery were evaluated by in vitro pressure-diameter tests on intact cylindrical segments at their in situ length. The basilar arteries from hypertensive animals became less distensible, reflecting increases in both structural and material stiffness, compared to their normotensive counterparts. The circumferential stress rapidly returned toward its homeostatic value by increasing the wall thickness within two weeks. Immunohistochemistry, which is capable of illustrating the localization and distribution of protein expression, was performed to examine changes in wall constituents in the aorta. The increased medial thickness observed in hypertensive pigs compared to normotensive pigs was due to hyperplasia of smooth muscle cells (SMCs) and accumulation of extracellular matrix proteins, which were accompanied by the phenotypic modulation of SMCs. The increased interlamellar thickness, collagen fibers, and the thickness of elastic lamina found in the inner media of hypertensive animal may be associated with the gradient of stress decreasing into the outer media. SMC proliferation, if any, was found evenly distributed across the media, however. In cases showing increased proliferation and matrix protein synthesis, the SMC contractile markers were down-regulated whereas the SMC synthetic markers were up-regulated. While the aortic intima appeared normal in the normotensive animals, neointima formation, which may predispose the vessel to atheroma formation, was found in the hypertensive animals. Immunohistochemistry of Hsp47 and procollagen revealed that the endothelial cells (ECs) may produce collagen, specifically type I collagen in response to hypertension and contribute to the thickened intima. In addition, lectin staining for ECs markers and immunostaining for eNOS suggested that endothelial cells may transdifferentiate into intimal SMCs. These findings suggested an alternative role that ECs may play in hypertension-induced atherogenesis.

Variation, or modulation, of suction feeding performance across two prey location treatments, as measured by peak subambient pressure generation, was studied in the Florida largemouth bass, Micropterus salmoides floridanus. Previous studies of suction feeding in centrarchids have excluded possible sources of performance variation to minimize the modulatory response. Florida bass are known to modulate their feeding kinematics when exposed to prey at different levels of elusiveness, and were in turn predicted to vary suction pressure generation when exposed to these conditions. Eight bass fed Palaemonetes sp. shrimp in an open water (elusive) setting and in a vegetated (non-elusive) setting were found to generate significantly different amounts of suction during prey capture (Fli48=5.676, p=0.021). Principal component analysis of variables derived from high speed digital video footage found that the suite of behaviors associated with the feeding strike also differed across prey location treatments. Bass feeding on open water prey approached at higher velocity, exhibited faster cranial kinematics, and generated larger values of suction force, while bass feeding on vegetated prey approached more slowly, had slower cranial kinematics, and generated smaller values of suction. Florida bass clearly modulate their repertoire of feeding activities in response to differing prey capture conditions.

This thesis aimed at studying mechanisms involved in control of tissue fluid homeostasis during inflammation.

The interstitial fluid pressure (P_IF) is of importance for control of tissue fluid balance. A lowering of P_IF in vivo will result in a transport of fluid from the circulation into the tissue, leading to edema. Loose connective tissues that surround blood vessels have an intrinsic ability to take up fluid and swell. The connective tissue cells exert a tension on the fibrous network of the tissues, thereby preventing the tissues from swelling. Under normal homeostasis, the interactions between the cells and the fibrous network are mediated by β1 integrins. Connective tissue cells are in this way actively controlling P_IF.

Here we show a previously unrecognized function for the integrin αVβ3, namely in the control of P_IF. During inflammation the β1 integrin function is disturbed and the connective tissue cells release their tension on the fibrous network resulting in a lowering of P_IF. Such a lowering can be restored by platelet-derived growth factor (PDGF) -BB. We demonstrated that PDGF-BB restored P_IF through a mechanism that was dependent on integrin αVβ3. This was shown by the inability of PDGF-BB to restore a lowered P_IF in the presence of anti-integrin β3 IgG or a peptide inhibitor of integrin αVβ3. PDGF-BB was in addition unable to normalize a lowered P_IF in β3 null mice. Furthermore, we demonstrated that extracellular proteins from Streptococcus equi modulated αVβ3-mediated collagen gel contraction. Because of the established concordance between collagen gel contraction in vitro and control of P_IF in vivo, a potential role for these proteins in control of tissue fluid homeostasis during inflammation could be assumed. Sepsis and septic shock are severe, and sometimes lethal, conditions. Knowledge of how bacterial components influence P_IF and the mechanisms for tissue fluid control during inflammatory reactions is likely to be of clinical importance in treating sepsis and septic shock.

A fast and efficient method to calculate time schedules for internal and boundary PRVs and flow modulation curves has been developed and implemented. Both time and flow modulation can be applied to a single inlet DMA. The time modulation methodology is based on solving a nonlinear programming problem (NLP). In addition, Genetic Algorithms (GA) has been proposed and investigated to calculate the optimal coefficients of a second order relationship between the flow and the outlet pressure for a PRV to minimize the background leakage. The obtained curve can be subsequently implemented using a flow modulation controller in a feedback control scheme. The Aquai-Mod® is a hydraulic device to control and modulate the outlet pressure of a PRV according to the valve flow. The controller was experimentally tested to assess its performance and functionality in different conditions and operating ranges. The mathematical model of the controller has been developed and solved, in both steady state and dynamic conditions. The results of the model have been compared with the experimental data and showed a good agreement in the magnitude and trends. A new method for combined energy and pressure management via integration and coordination of pump scheduling with pressure control aspects has been created. The method is based on formulating and solving an optimisation NLP problem and involves pressure dependent leakage. The cost function of the optimisation problem represents the total cost of water treatment and pumping energy. Developed network scheduling algorithm consists of two stages. The first stage involves solving a continuous problem, where operation of each pump is described by continuous variable. Subsequently, the second stage continuous pump schedules are discretised using heuristic algorithm. Another area of research has been developing optimal feedback rules using GA to control the operation of pump stations. Each pump station has a rule described by two water levels in a downstream reservoir and a value of pump speed for each tariff period. The lower and upper water switching levels of the downstream reservoir correspond to the pump being “ON” or “OFF”. The achieved similar energy cost per 1 Ml of pumped water. In the considered case study, the optimal feedback rules had advantage of small number of ON/OFF switches, which increase the pump stations lifetime and reduce the maintenance cost as well.

Background: Emerging evidence suggests that aerobic exercise and conditioned pain modulation may be advocated in treating patients with musculoskeletal pain. The effects of lower extremity aerobic exercise and conditioned pain modulation on evoked shoulder pain are not known. Purpose: To determine the acute effects of lower extremity aerobic exercise and conditioned pain modulation on outcomes of evoked shoulder pain from pain pressure threshold measurements. Study Design: Repeated measures. Methods: Thirty (30) healthy volunteers were tested over the course of two sessions. Session 1 consisted of collecting pain pressure threshold measurements over the infraspinatus before and immediately following a conditioned pain modulation with cool water. Session 2 consisted of collecting pain pressure threshold measurements over the infraspinatus before and immediately following a bout of lower extremity aerobic exercise on a recumbent stepper apparatus. Results: Pain pressure threshold was not significantly influenced by the conditioned pain modulation using cool water (p=0.725). Pain pressure threshold was significantly increased immediately following the lower extremity exercise session (P<0.001). Conclusion: Conditioned pain modulation with cool water did not produce any significant changes in pain pressure threshold. Lower extremity aerobic exercise acutely increased pain pressure threshold in participants with experimentally induced shoulder pain. Physical therapists may consider lower extremity aerobic exercise to produce short-term hypoalgesic effects and facilitate the application of more active interventions.

The aim of this study was to investigate a sensory intervention of moderate pressure touch on children with sensory modulation disorder on the outcomes of sleep behaviors and social participation. 50 children, aged 6-11 years, with both sensory modulation disorder and sleep difficulties were randomly divided into an experimental group and a control group. The experimental group participants received three weeks of nightly massage by their parents. The parents filled out questionnaires reporting on sleep behaviors, sensory modulation, and social participation, as well as recording a sleep log, and determining goal attainment scaling goals. The questionnaires used were the Short Sensory Profile, the Child Sleep Habits Questionnaire, the Child Behavior Checklist (CBCL), and the Sensory Processing Measure social sub-section. Significant improvement was found between the total and sub-group scores of sleep and social participation measures. While obstructive sleep disorders remained unchanged, behavioral sleep difficulties of sleep onset, sleep anxiety, parasomnias, sleep duration, and daytime sleepiness, as well as the total sleep scores ( F(1,48)=24.71, p

Introdução: A descontinuação da ventilação mecânica (VM) e a restituição da ventilação espontânea podem acarretar importantes alterações cardiovasculares devido a modificações da pressão intratorácica. O comportamento da modulação autonômica avaliada através da variabilidade da freqüência cardíaca (VFC) durante o desmame da VM e ainda não está bem esclarecido, assim como sua repercussão nas variáveis cardiorrespiratórias. Objetivo: Verificar o efeito do tubo T (TT) e da ventilação com pressão suporte (PSV), durante o desmame da VM, sobre variáveis cardiorrespiratórias e variabilidade da freqüência cardíaca. Pacientes e Métodos: Foram avaliados 30 pacientes, em VM por ≥ 48 horas, que preencheram os critérios para desmame. Os pacientes foram submetidos aos dois modos de desmame com randomização para a escolha de uma das seqüências (basal, PSV, repouso, TT; ou, basal, TT, repouso, PSV). A VFC foi avaliada por análise espectral da freqüência cardíaca em VM, PSV, TT, com 30 minutos de duração cada uma e 30 minutos de repouso entre as intervenções. Foram analisadas no final de cada período as seguintes variáveis cardiorrespiratórias: freqüência respiratória (f), volume minuto (VE), volume corrente (VT), índice de respiração rápida e superficial (f/VT), saturação periférica de oxigênio (SpO2), freqüência cardíaca (FC) e a pressão arterial. Na VFC foi calculada a potência espectral total (PT), os componentes de baixa freqüência (BF), de alta freqüência (AF) e a razão entre os componentes de baixa/alta freqüência (BF/AF). Resultados: Durante o método TT, comparando com o período basal, ocorreu um aumento da ƒ (19 ± 4 vs 25 ± 5 rpm), f/VT (37 ± 16 vs 55 ± 23) e FC (92 ± 18 vs 98 ± 16 bpm), com redução da SpO2 (97 ± 1.7 vs 95 ± 3.1 %). Quando reduzido os valores da PSV, as variáveis cardiorrespiratórias foram semelhantes aos valores basais. Os índices da VFC não foram alterados durante o desmame da VM, independentemente do método de desmame utilizado. Conclusão: Nossos resultados sugerem que o uso de PSV durante o desmame da VM não afeta as variáveis cardiorrespiratórias estudadas, mas o uso do método TT causou alterações cardiorrespiratórias, provavelmente devido ao aumento do trabalho respiratório. A VFC permaneceu a mesma durante o desmame e o aumento da FC durante o TT provavelmente ocorreu através de mecanismos não autonômicos.
Introduction: The discontinuation of mechanical ventilation (MV) and the recovery of spontaneous breathing can lead to important cardiovascular alterations due to changes in the intrathoracic pressure. The autonomic modulation assessed through heart rate variability (HRV) during weaning from MV and its impact on cardiorespiratory variables has not been well elucidated yet. Objective: To evaluate the effect of T-tube (TT) and pressure support ventilation (PSV) during weaning from MV on cardiorespiratory variables and heart rate variability. Patients and Methods: Thirty patients who had received MV for ≥ 48 hours and who met the criteria for weaning were assessed. Two different weaning methods were used and randomization was performed to choose one of the following sequences (baseline, PSV, rest, TT; or baseline, TT, rest, PSV). HRV was assessed by heart rate spectral analysis during MV, PSV, and TT. Each intervention lasted 30 minutes and there was a 30-minute rest period between the interventions. At the end of each period of time, the following cardiorespiratory variables were analyzed: respiratory rate (f), minute ventilation (VE), tidal volume (VT), rapid shallow breathing index (f/VT), peripheral oxygen saturation (SpO2), heart rate (HR) and blood pressure. In the HRV, the total spectral power (TP), the low frequency (LF) and the high frequency (HF) components, and the ratio between the low/high frequency (LF/HF) components were calculated. Results: During TT ventilation, regarding the baseline period, there was an increase in ƒ (19 ± 4 vs 25 ± 5 breaths.min), f/VT (37 ± 16 vs 55 ± 23) and HR (92 ± 18 vs 98 ± 16 beats.min), with decrease in the SpO2 (97 ± 1.7 vs 95 ± 3.1 %). When the PSV values dropped, the cardiorespiratory variables were similar to the baseline values. The HRV values did not change during weaning from MV, regardless the weaning methods used. Conclusion: Our results suggest that using PSV during weaning from MV does not affect the cardiorespiratory variables studied, but use of TT method caused cardiorespiratory alterations, probably due to an increase in the respiratory workload. Heart rate variability remained the same during weaning and the increase in HR during TT, probably occurred through nonautonomic mechanisms.

O treinamento resistido progressivo de alta intensidade tem sido empregado para aumentar a massa e força musculares de indivíduos idosos. Entretanto, existe na área clínica alguma preocupação de que esse treinamento possa promover efeitos adversos sobre o sistema cardiovascular envelhecido. Assim, o objetivo do presente estudo foi avaliar os efeitos do treinamento resistido progressivo de alta intensidade sobre a pressão arterial clínica e ambulatorial e seus mecanismos hemodinâmicos e neurais de idosos. Para tanto, 25 indivíduos com idade entre 60 e 80 anos foram divididos aleatoriamente em dois grupos: Grupo Treinamento Resistido (N=12, 7 mulheres, 64±1 anos - 2 sessões/semana, 7 exercícios, 2-4 séries, 10-4 RM) e Grupo Controle (N=13, 11 mulheres, 63±1 anos - nenhum treinamento). Antes e após 4 meses, a força dinâmica máxima, a área de secção transversa do músculo quadríceps, a pressão arterial clínica (posição deitada e sentada) e ambulatorial, os determinantes hemodinâmicos e a modulação autonômica cardiovascular (posição deitada com respiração livre e controlada e posição sentada com respiração livre) foram avaliados nos dois grupos. Comparando-se os valores medidos no início e no final do estudo, a força dinâmica máxima de membros superiores e inferiores e a área de secção transversa do músculo quadríceps aumentaram no Grupo Treinamento Resistido (+32, +46 e +5%, respectivamente, P<0,05) e não se modificaram no Grupo Controle. As pressões arteriais sistólica e diastólica não se alteraram no Grupo Treinamento Resistido (posição deitada, 119±10 vs. 120±10 e 74±6 vs. 74±7 mmHg; posição sentada, 125±8 vs. 121±9 e 78±6 vs. 76±7 mmHg, respectivamente, P>0,05) e nem no Grupo Controle (posição deitada, 121±11 vs. 119±10 e 73±5 vs. 72±4 mmHg; posição sentada, 125±11 vs. 124±9 e 75±8 vs. 74±5 mmHg, respectivamente, P>0,05). Da mesma forma, a resistência vascular periférica, o débito cardíaco, o volume sistólico e a frequência cardíaca não se alteraram em nenhum dos grupos (Treinamento Resistido = 26±5 vs. 30±5 mmHg/L.min-1; 3,8±0,9 vs. 3,2±0,4 L/min; 54±11 vs. 43±10 ml e 70±9 vs. 75±12 bpm; Controle = 29±8 vs. 31±10 mmHg/L.min-1; 3,5±1,0 vs. 3,1±0,7 L/min; 54±16 vs. 50±14 ml e 66±11 vs. 65±10 bpm, respectivamente, P>0,05). Com relação aos mecanismos neurais, o balanço simpatovagal (BF/AFR-R) não se modificou em nenhuma das três situações (posição deitada com respiração livre e controlada e posição sentada com respiração livre) no Grupo Treinamento Resistido (4,1±5,4 vs. 1,9±1,3; 0,7±0,6 vs. 0,9±0,9 e 3,5±5,7 vs. 5,0±8,1, respectivamente, P>0,05) nem no Grupo Controle (2,3±2,8 vs. 2,0±1,6; 0,4±0,4 vs. 0,4±0,4 e 3,0±3,7 vs. 2,8±2,8, respectivamente, P>0,05). A sensibilidade barorreflexa espontânea e a pressão arterial ambulatorial também não se alteraram em nenhum dos grupos. Em conclusão, o treinamento resistido de alta intensidade foi efetivo em aumentar a força dinâmica máxima e a área de secção transversa muscular de indivíduos idosos audáveis, sem modificar a pressão arterial clínica e ambulatorial, nem seus determinantes hemodinâmicos e mecanismos de regulação neural
Progressive high-intensity resistance training has been performed to increase of muscle mass and strength in elderly subjects. However, some clinical concerns exist about the possible adverse cardiovascular effects of this training on cardiovascular function and regulation in elderly. Thus, the aim of this study was to evaluate the effects of progressive high-intensity resistance training on blood pressure and its hemodynamic and neural mechanisms in elderly subjects. To investigate this issue, 25 subjects aged between 60 and 80 years were randomly divided into two groups: Resistance Training Group (N=12, 7 females, 64±1 years 2 sessions/week, 7 exercises, 2-4 sets, 10-4 RM) and Control Group (N=13, 11 females, 63±1 years no training). Before and after 4 months, maximal strength, quadriceps cross-sectional area, clinical (supine and sitting position) and ambulatory blood pressure, hemodynamic determinants, and cardiovascular autonomic modulation (supine position with free and controlled breathing and sitting position with free breathing) were measured. Comparing values measured at the beginning and the end of the study, maximal strength of upper and lower limbs, and quadriceps cross-sectional area increased in the Resistance Training Group (+32, +46 e +5%, respectively, P>0.05). Similarly, peripheral vascular resistance, cardiac output, stroke volume and heart rate also did not change in neither of the groups (Resistance Training = 26±5 vs. 30±5 mmHg/L.min-1; 3.8±0.9 vs. 3.2±0.4 L/min; 54±11 vs. 43±10 ml; and 70±9 vs. 75±12 bpm; Control Group = 29±8 vs. 31±10 mmHg/L.min-1; 3.5±1.0 vs. 3.1±0.7 L/min; 54±16 vs. 50±14 ml; and 66±11 vs. 65±10 bpm, respectively, P>0.05). In regard to the neural mechanisms, cardiac sympathovagal balance (LF/HFR-R) also did not change in any of the situations (supine position with free and controlled breathing, and sitting position with free breathing) in the Resistance Training Group (4.1±5.4 vs. 1.9±1.3; 0.7±0.6 vs. 0.9±0.9; 3.5±5.7 vs. 5.0±8.1, respectively, P>0.05) nor in the Control Group (2.3±2.8 vs. 2.0±1.6; 0.4±0.4 vs. 0.4±0.4; 3.0±3.7 vs. 2.8±2.8, respectively, P>0.05). The spontaneous baroreflex sensitivity and ambulatory blood pressure also did not change in neither of the groups. In conclusion, the progressive high-intensity resistance training was effective in increasing muscle mass and strength in healthy elderly subjects, without changing clinic and ambulatory blood pressure as well as their hemodynamic and neural mechanisms. respectively, P<0.05), and did not change in the Control Group. Systolic and diastolic blood pressure did not change in the Resistance Training Group (supine, 119±10 vs. 120±10 and 74±6 vs. 74±7 mmHg; sitting 125±8 vs. 121±9 and 78±6 vs. 76±7 mmHg, respectively, P>0.05) nor in the Control Group (supine, 121±11 vs. 119±10 and 73±5 vs. 72±4 mmHg; sitting, 125±11 vs. 124±9 and 75±8 vs. 74±5 mmHg

Pain and movement are intimately connected and nearly universal human experiences. However, our understanding of the extent, significance, and mechanisms of pain-movement relationships is limited. While pain is a normal, protective response to injury and potentially harmful stimuli, prolonged or dysfunctional neuromuscular adaptions in response to pain can contribute to a variety of pain conditions. Alternatively, movement (in the form of global physical activity, individual exercise programs, and/or specific motor learning/functional tasks) is often prescribed to help decrease pain and improve function. While attempts have been made to show an effect of movement on pain or to better understand altered movement strategies in response to pain, much of the research has been limited to animal models or to those with specific persistent or chronic pain conditions limiting generalizability and interpretability. Therefore, this research sought to advance current understanding of the relationships between physical activity and normal variability in centrally- and peripherally-mediated pain in healthy adults. Additionally, we sought to characterize changes in reflexive motor responses in the upper extremity to an endogenous, naturally-occurring, long-lasting acute muscle pain. The results of these investigations indicate that greater, self-reported intense (i.e. vigorous) and leisure activity are more strongly associated with decreased pain sensitivity than is pain modulation or measured activity (via accelerometry). Future research is needed to determine directionality of these relationships. Further, reflexive motor responses to endogenous, acute muscle pain in the upper extremity were not significantly altered indicating that changes in pain-related, movement strategies may be more strongly influenced by supraspinal adaptations. These results may have value in improving understanding of pain-related, movement sequelae and directing future research in this area.

La détermination du champ de pression dans un écoulement et/ou des efforts sur un profil en mouvement à partir de mesures de vitesses effectuées dans le milieu fluide est une problématique actuelle qui intéresse de nombreux domaines de recherche en mécanique des fluides. On pourrait citer en particulier, les systèmes de récupération d'énergie (éolienne, hydrolienne) ou bien les systèmes de contrôle optimal d'aubes de guidage de turbine, etc…Dans ce mémoire, nous apportons notre contribution à ce problème en proposant dans un premier temps, une méthode originale qui permet, à partir de champs de vitesses instationnaires obtenus par mesure optiques PIV, d'approcher ces champs dans l'ensemble du milieu (profil inclus) en utilisant la théorie des polynômes orthogonaux de Legendre. L'équation de Navier-Stokes permet alors d'obtenir des gradients de pression polynomiaux dans l'ensemble du milieu fluide et de pouvoir ainsi calculer le champ de pression dans l'écoulement et ensuite, en utilisant l'équation de bilan de mouvement dans un domaine de référence judicieusement choisi, de déterminer les efforts sur un profil mobile en oscillation. Cette méthode est alors validée sur un profil fixe à partir de données simulées numériquement et de données expérimentales.Dans un deuxième temps, après une série de mesures optiques PIV sur un profil NACA0015 soumis à différents types d'oscillations, nous appliquons la méthode décrite précédemment pour reconstruire les champs de pressions instationnaires et évaluer les efforts instantanées et moyens sur le profil. L'étude d'un certain nombres de plages de fréquences et d'amplitudes permet de comparer nos résultats, pour la recherche d'une meilleure efficacité
The determination of the pressure field in a flow and/or forces on a moving profile from measurements of velocities carried out in the fluid is a current problem that is of interest to many domains of research in fluid mechanics like the energy recovery systems (wind, hydro) or the speed control of hydraulic turbines, etc…In this PhD thesis, we make a contribution to this problem by initially proposing an original method which allows us to approach unsteady velocity fields in the whole of the flow obtained by PIV optical measurements (including the profile) using Legendre's orthogonal polynomial theory. The Navier-Stokes equations then make it possible to obtain polynomial pressure gradients in the whole of the fluid and thus to be able to calculate the pressure field in the flow by using the momentum balance equation in a judiciously chosen reference range, to determine the forces on an oscillating mobile profile. This method is then validated on a fixed profile using numerically simulated data and experimental data.In a second step, from series of flow PIV measurements on a NACA0015 profile subjected to different types of oscillations, we apply the method described above to reconstruct the unsteady pressure fields and to evaluate the instantaneous and average forces on the profile. The study of a certain number of ranges of frequencies and amplitudes makes it possible to compare our results, in order to seek a better efficiency

O treinamento de caminhada (TC) é recomendado para o tratamento de indivíduos com claudicação intermitente (CI) porque melhora a capacidade de caminhada. Além disso, seria interessante que o TC também promovesse modificações benéficas no sistema cardiovascular, pois os eventos cardiovasculares são a principal causa de morte nestes indivíduos. No entanto, os efeitos cardiovasculares do TC em indivíduos com CI foi pouco estudado. Assim, o objetivo deste estudo foi verificar o efeito do TC sobre o risco, a função e a regulação cardiovasculares em indivíduos com CI. Quarenta e dois indivíduos com CI foram divididos de forma aleatória em 2 grupos: controle (GC, n=20, sessões de 30 min de alongamento) e treinamento de caminhada (GT, n=22, 15 séries de 2 min de caminhada em intensidade correspondente à frequência cardíaca (FC) do limiar de dor intercalados por 2 min de repouso passivo). Nos dois grupos, a intervenção foi realizada 2 vezes/semana durante 12 semanas consecutivas. No início e ao final do estudo, os indivíduos realizaram as seguintes avaliações: glicemia e perfil lipídico de jejum; índice de massa corporal; capacidade de caminhada; consumo de oxigênio no 1º estágio e no pico do teste de esforço; índice tornozelo-braço (ITB) de repouso; janela isquêmica após teste ergoespirométrico; pressão arterial (PA) em repouso (auscultatória) e de 24 horas (oscilométrica); débito cardíaco (DC - reinalação de CO2); FC (ECG); volume sistólico (VS); resistência vascular (RV) sistêmica, do antebraço e da perna (plestismografia); componentes de alta (AF) e baixa (BF) frequência da variabilidade da FC; e sensibilidade barorreflexa espontânea (SBR). Mudanças significantes (P<0,05) ao longo do tempo e entre os grupos foram verificadas pela análise de variância ANOVA de dois fatores para medidas repetidas. O TC aumentou significantemente a capacidade de caminhada (Δ=+302±85m) e a SBR (Δ=+2.13±1.07 ms/mmHg), e diminuiu o VO2) no 1º estágio do teste (Δ=-1,8±0,4ml.kg-1.min-1), a janela isquêmica (Δ=- 0,40±0,38mmHg.min.m-1), a PA média (Δ=-5±2mmHg), a variabilidade da PA média de 24h (Δ=-0,8±0,2mmHg), o DC (Δ=-0.37±0.24L/min), a FC (Δ=- 4±2bpm), a RV do antebraço (Δ=-8.5±2.8 U) e a razão BF/AF (Δ=-1.24±0.99). A glicemia, o perfil lipídico, o índice de massa corporal, o VO2) pico, o ITB de repouso e a RV sistêmica e da perna não foram modificadas pelo TC. Não houve mudança em nenhuma variável no GC. Em conclusão, o TC melhorou a capacidade de caminhada, a economia de caminhada e a janela isquêmica. Além disso, o TC melhorou a função (PA, DC, FC e RV antebraço) e a regulação (BF/AF e SBR) cardiovasculares em indivíduos com CI. Estas alterações fornecem suporte adicional para a utilização do TC no tratamento de indivíduos com CI
Walking training (WT) is recommended for the treatment of patients with intermittent claudication (IC) because it improves walking capacity. Moreover, it would be interesting that WT also promotes beneficial changes on cardiovascular system, since cardiovascular events are the main causes of death in these patients. Nevertheless, the effects of WT on cardiovascular system in patients with IC have been poorly studied. Thus, the objective of this study was to investigate the effects of WT on cardiovascular risk, function and regulation in patients with IC. Forty-two IC patients were randomly divided into 2 groups: Control (CG, n=20, 30 min of stretching exercises) and walking training (TG, n=22, 15 sets of 2:2-min walk:rest at the heart rate (HR) of pain threshold). In both groups, the intervention was performed twice/week for 12 consecutive weeks. At the beginning and end of the study, the following measured were done: fasting glycemia and lipid profile; body mass index; walking capacity; VO2 at the first stage and the peak of a treadmill test; ankle brachial index (ABI); ischemic window after maximal test; resting (auscultatory) and 24-hour (oscillometric) blood pressure (BP); cardiac output (CO - CO2 rebreathing); heart rate (HR - ECG); stroke volume (SV); systemic, forearm and leg vascular resistance (VR - plethysmography); low- (LF) and high-frequency (HF) components of HR variability; and spontaneous baroreflex sensitivity (SBS). Significant changes (P<0.05) over time and between groups were assessed by 2-way ANOVA for repeated measures. WT significantly increased walking capacity (Δ=+302±85m) and SBS (Δ=+2.13±1.07 ms/mmHg), and decreased VO2 at the first stage of treadmill test (Δ=-1.8±0.4ml.kg-1.min-1), ischemic window (Δ=-0.40±0.38mmHg.min.m-1), mean BP (Δ=-5±2mmHg), ambulatory mean BP variability (Δ=-0,8±0,2 mmHg), CO (Δ=-0.37±0.24 L/min), HR (Δ=- 4±2bpm), forearm VR (Δ=-8.5±2.8 U) and LF/HF (Δ=-1.24±0.99). Glycemia, lipid profile, body mass index, VO2 peak, ABI, systemic and leg VR were unchanged following WT. There was no significant change for any variable in CG. In conclusion, WT enhanced walking capacity, walking economy and ischemic window. In addition, WT improved cardiovascular function (BP, CO, HR and forearm VR) and autonomic regulation (LF/HF, SBS) in patients with IC. These changes provide further support for the use of regular WT in treating patients with IC

Ce travail porte sur la synthèse et la caractérisation de nouveaux matériaux multiferroïques basés sur le concept très récent de la Ferroélectricité Hybride Impropre.Deux classes de matériaux ont été envisagées : les oxydes de type Ruddlesden-Popper NaRMO4 (R=Y, La; M= Mn, Cr) et les doubles pérovskites ordonnées NaLnCoWO6 (Ln= Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb). Les essais de synthèse sur la première classe n’ont pas permis d’obtenir les composés visés. Pour la seconde classe, l’ensemble des composés ont pu être obtenus par synthèse par voie solide à haute température. Les composés NaLnCoWO6 (Ln=La, Pr, Nd) ont été synthétisés à pression ambiante. L’usage des techniques de Hautes Pressions – Hautes Températures (HP-HT) a permis de stabiliser les composés contenant des terres rares plus petites et d’obtenir ainsi neuf nouveaux composés aux propriétés inédites.L’utilisation combinée de la diffraction sur poudre des rayons X au synchrotron et des neutrons a permis une étude structurale fine de la famille des doubles pérovskites ordonnées NaLnCoWO6. Les groupes d’espace ont été déterminés grâce aux affinements Rietveld des diffractogrammes de Rayons X sur poudre haute résolution. Les composés NaLnCoWO6 (Ln=La, Pr, Nd) cristallisent dans le groupe d’espace centrosymétrique C2/m tandis que les 9 nouveaux composés (Ln= Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb) cristallisent dans le groupe d’espace polaire P21. Des mesures de génération de seconde harmonique confirment la structure non-centrosymétrique des nouveaux composés. L’analyse adaptée des modes de symétrie des composés cristallisant dans la structure polaire montre que l’amplitude du mode polaire induit augmente avec la diminution de la taille du cation Ln3+. La polarisation estimée à partir des affinements de la structure pourrait atteindre jusqu’à ~20µC/cm2.Une transition de phase présentant une très large hystérésis en température (~150K) a été observée par diffraction des neutrons pour le composé NaLaCoWO6. De plus, les images obtenues en Microscopie Electronique en Transmission révèlent la présence de bandes dans la phase haute température. Cette superstructure présente une périodicité de 12ap selon la direction [100]p ou [010]p . On a pu montrer à l’aide d’observations en STEM (microscopie à balayage en transmission) combinées avec des mesures en EELS (spectroscopie de pertes d’énergie des électrons) que ce contraste de bandes n’est pas lié à une variation de composition mais bien à une variation structurale. Différents modèles de rotations des octaèdres d’oxygènes ont été élaborés pour valider les données expérimentales obtenues par diffraction des rayons X et de neutrons. Le schéma de rotation qui décrit au mieux les données est a-a-c0. Concernant la phase basse température le groupe d’espace attribué est le groupe polaire P21.Les caractérisations magnétiques ont été réalisées pour toutes ces phases. Tous les composés NaLnCoWO6 s’ordonnent dans une configuration antiferromagnétique. Les températures de Néel varient entre 4 et 13K en fonction de la nature de la terre-rare. Les moments effectifs déterminés par la loi de Curie-Weiss sont en accord avec les moments théoriques attendus. Toutes les températures de Weiss sont négatives traduisant le fait que les interactions antiferromagnétiques sont prépondérantes dans ces systèmes. Les structures magnétiques ont été déterminées pour les composés Ln= Y, La, Tb, and Ho. Pour ces mêmes composés, des mesures diélectriques en fonction de la température et du champ magnétique ont permis de mettre en évidence un couplage magnéto-diélectrique conséquent pour Ln=Y and Ho. Les mesures de courant pyroélectrique autour de la transition magnétique montrent qu’il existe une polarisation induite par l’ordre magnétique dans le composé NaYCoWO6.. C’est la première mise en évidence expérimentale d’un couplage magnéto-électrique dans la famille des doubles pérovskites ordonnées AA’BB’O6
In this study, new magneto-electric materials were synthesized on the basis of the very recently recognized ferroelectric inducing mechanism, hybrid improper ferroelectricity, and structural and physical properties characterizations were carried out on these new phases.Two classes of materials were focused on: the Ruddlesden-Popper oxides NaRMO4 (R=Y, La; M= Mn, Cr) and the doubly ordered perovskites NaLnCoWO6 (Ln= Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Yb). Attempts to synthesize the former class failed to give the target phases. All compounds in the latter class were prepared successfully by solid-state reactions at high temperature, among which the compounds NaLnCoWO6 (Ln=La, Pr, Nd) were prepared at ambient pressure while the other nine compounds were synthesized at high pressure.The structural study of the doubly ordered perovskite family NaLnCoWO6 was performed by synchrotron X-ray powder diffraction (SXRPD) and neutron powder diffraction (NPD). Based on the Rietveld refinement of the SXRPD patterns, the space groups were assigned. NaLnCoWO6 (Ln=La, Pr, Nd) compounds crystallize in the centrosymmetric C2/m symmetry, whereas the other nine new compounds crystallize in the polar space group P21. Second harmonic generation measurements on powder confirmed the non-centrosymmetric structure of the new compounds. Symmetry mode analysis demonstrates that the amplitude of the induced polar mode increases with a decreasing Ln cation size. The amplitude of the polarization was estimated from the refined structures, and can be as large as ~20µC/cm2.A structural phase transition was observed by NPD in NaLaCoWO6 with a large temperature hysteresis of ~150K. In addition, stripes were observed on the high-resolution transmission electron microscopy (TEM) images in the high temperature phase. The periodicity of this superstructure is 12ap along either the [100]p or [010]p direction. Further investigations by scanning TEM and electron energy loss spectroscopy revealed that the contrast of the stripes is due to a structural modulation rather than a compositional variation. Octahedral tilt twinning models were built with different tilting schemes to fit the observed SXRPD and NPD patterns. The tilting scheme a-a-c0 describes successfully the data. The low temperature phase was unambiguously determined to possess the polar space group P21.Magnetic and electric properties were experimentally characterized. All NaLnCoWO6 compounds order antiferromagnetically below TN which is between 4 and 13K. Curie-Weill fits were performed for all compounds, yielding reasonable effective magnetic moments compared to the theoretical ones. Weiss temperatures were all determined to be negative further indicating that antiferromagnetic interactions are dominant in these systems. Magnetic structures were determined for four NaLnCoWO6 (Ln= Y, La, Tb, and Ho) compounds, of which two have non-magnetic Ln cations (Y and La) and two have magnetic ones (Tb and Ho). Magneto-dielectric coupling was experimentally observed in compounds NaLnCoWO6 (Ln=Y, Tb, Ho) by dielectric measurements as a function of temperature and magnetic field. Polarization was derived for the Y and Ho compounds from pyroelectric current measurement, however, only the NaYCoWO6 compound demonstrates a polar behavior which cannot be switched. This is the first evidence that electric polarization can be induced by the magnetic ordering in the AA’BB’O6 class materials

L’exploration expérimentale de l’intrication quantique est un domaine de recherche très actif actuellement. Les systèmes d’électrodynamique quantique en cavité permettent notamment de générer de l’intrication dans des ensembles de plusieurs dizaines de particules, grâce à l’interaction à longue portée fournie par un mode du champ électromagnétique. Mon travail de thèse a consisté à mettre en place un nouveau dispositif expérimental afin d’assurer le chargement rapide et fiable d’une cavité optique miniaturisée à l’intérieur de laquelle l’adressage et la détection d’atomes uniques viennent s’ajouter à l’interaction collective fournie par le mode de la cavité. La tomographie quantique des états intriqués requière l’acquisition d’un grand nombre de données expérimentales, un soin tout particulier doit donc être porté quand à la stabilité et à la rapidité de répétition de l’expérience. Pour satisfaire à ces critères, un système de lasers particulièrement compacts et robustes, a été conçu et fabriqué afin d’assurer le refroidissement et l’interaction avec les atomes. Pour permettre la rapidité de répétition de l’expérience, une source de rubidium est utilisée en mode impulsionnel dans l’unique cellule à vide. Elle permet de moduler temporellement la pression atomique en fonction des besoins de l’expérience. Un chargement prompt du piège magnéto-optique est alors possible sans réduire la durée de vie des atomes dans la cavité, au moment où se déroulent les expériences. Le transport des atomes entre leur position de capture et le centre de la cavité s’effectue grâce à un piège dipolaire, déplacé selon son axe fort de confinement à l’aide d’un déflecteur acousto-optique. Cela permet un déplacement rapide, de l’ordre de la centaine de millisecondes pour une distance de 1,5 cm. Grâce à cette combinaison de techniques, ce nouveau dispositif expérimental devrait donner accès à la physique riche des systèmes intriqués à plusieurs dizaines de particules
The study of quantum entanglement is a very active research field. Cavity quantum electrodynamics systems are versatile tools allowing for instance entanglement in mesoscopic systems, that is to say with about a hundred particles. The purpose of the new experimental setup built during this thesis is to reach the single atom manipulation and detection level while working with mesoscopic ensembles, collectively coupled to the cavity mode. Toward this goal, three new experimental techniques have been developed to enable reliable and fast data acquisition rate, essential to reconstruct entangled states by quantum tomography means. First, robust extended cavity diode lasers have been constructed, allowing acquisitions that last for days. Then, a pulsed atomic source has been set up, it combines the advantages of fast magneto-optical trap loading and long lifetime in conservative traps by modulating the pressure inside a single vacuum chamber apparatus on a short timescale. Finally, to ensure the fast transport of cold atomic ensembles from the magneto-optical trap to the cavity position, a dipole trap moved with an acousto-optic deflector has been built. This allows a transport over few centimetres leaving the full optical access to the atomic cloud for other manipulations. Thanks to this new experimental setup, we hope to contribute to the understanding of the rich physics lying beyond multi-particle entangled systems

Résumé : Introduction: À ce jour, notre compréhension des mécanismes neurophysiologiques responsables du développement d'une douleur chronique est encore relativement limitée. Il est proposé que certaines modifications dans l'efficacité des mécanismes endogènes d'inhibition descendante de la douleur pourraient contribuer à ce phénomène. Considérant l'importance de la neurotransmission monoaminergique dans les mécanismes descendants de modulation de la douleur, autant inhibiteur que facilitateur, nous émettons l'hypothèse que la persistance temporelle d'une douleur peut provoquer des modifications dans la fonctionnalité des deux systèmes majeurs (sérotoninergique et noradrénergique) sous-jacents à ces mécanismes de contrôle endogène, participant ainsi à la dynamique de développement et à la progression des états de douleur chronique à travers le temps. Objectif général: En utilisant une approche translationnelle, nous avons exploré l'association entre la fonctionnalité (centrale & périphérique) des systèmes de neurotransmission monoaminergique et l'efficacité des mécanismes descendants d’inhibition pendant le développement et la progression d'une douleur chronique. Résultats cliniques: D'une part, nos résultats répliquent plusieurs observations de la littérature ayant démontré une diminution de l'efficacité des mécanismes descendants d’inhibition de la douleur (à l'aide d'un paradigme de modulation conditionnée de la douleur; MCD) chez des sujets souffrant de douleur musculosquelettique chronique (sujets CP). Chez ces mêmes sujets, nous observons également une diminution des concentrations plasmatiques basales en noradrénaline (NA) et métanéphrine, lorsque comparés à des sujets sains (sujets PF). Pour tous les sujets testés (PF et CP), une association positive est mise en évidence entre l'efficacité de la MCD et les concentrations plasmatiques basales en NA et métanéphrine. Par conséquent, ces concentrations des catécholamines dans le plasma pourraient servir d'indicateurs moléculaires de l'efficacité latente de la MCD. Par ailleurs, aucune différence dans l'activité monoaminergique et aucune association avec l'efficacité de la MCD n'ont été observées au niveau du liquide céphalorachidien (LCR). Résultats précliniques: D'autre part, nous proposons un nouveau modèle de douleur à double atteinte chez le rongeur (i.e., induction initiale d'une douleur persistante [la 1ere atteinte] et activation subséquente des mécanismes descendants de modulation de la douleur à l'aide d'une douleur tonique [la 2e atteinte]). Ce paradigme expérimental nous permet ainsi d'évaluer l'efficacité des mécanismes descendants de modulation de la douleur chez les rongeurs en contexte de douleur chronique. Ainsi, nous mettons en évidence une diminution de la réponse comportementale à une douleur tonique (dans le test à la formaline), 28 jours après l'induction d'une douleur neuropathique (modèle de constriction chronique du nerf sciatique; CCI), lorsque comparés aux rats sham. Bien que cette diminution des comportements nociceptifs soit encore observable 168 jours après le début de la neuropathie, celle-ci semble tout de même s'amenuiser à travers le temps. Parallèlement, en l'absence de stimulation nociceptive tonique, une augmentation des concentrations en sérotonine et noradrénaline est observée au niveau central (i.e., dans le LCR) 12 jours après l'induction de la douleur neuropathique, avant de retourner ensuite à un niveau comparable à celui des rats sham au jour 28. Par ailleurs, la réponse comportementale observée au jour 28 est visible seulement dans un modèle de douleur neuropathique (CCI), et non lorsqu'une douleur inflammatoire est utilisée comme douleur persistante initiale. Conclusions: En contexte de douleur chronique, nos résultats chez l'humain confirment la présence de modifications dans l'efficacité des mécanismes descendants d’inhibition de la douleur, en plus de soutenir le concept émergent qui suggère que les différences dans l'efficacité de ceux-ci pourraient être associées à des différences individuelles dans certains processus périphériques (comme la relâche de catécholamines dans le sang), pouvant ultimement être impliquées dans la régulation cardiovasculaire. Par ailleurs, nos résultats chez le rongeur suggèrent que des changements dynamiques (spécifiques au type de douleur) dans l'efficacité des mécanismes descendants de modulation, ainsi que dans la fonctionnalité centrale des systèmes de neurotransmission monoaminergique, se produisent lors de la progression d'une douleur chronique. Dans son ensemble, cette thèse apporte de nouvelles informations au sujet des changements neurophysiologiques temporels au sein des mécanismes descendants de modulation de la douleur pouvant être impliqués dans le développement et la progression de la douleur chronique.
Abstract : Introduction: Hitherto, our understanding about the neurophysiological mechanisms responsible for the development of chronic pain is still relatively limited. It is suggested that modifications in the efficacy of endogenous pain inhibitory mechanisms could contribute to this phenomenon. Considering the importance of monoaminergic neurotransmission in descending pain modulation, either of inhibitory or facilitatory influence, we hypothesize that temporal persistence of pain can trigger modifications in the functionality of the two major systems (serotoninergic and noradrenergic) underlying these endogenous control mechanisms, thus participating in the development and progression of chronic pain states. General objective: Adopting a translational approach, we explored the association between the functionality (central & peripheral) of monoaminergic neurotransmission and the efficacy of descending inhibitory mechanisms during the development and progression of chronic pain. Clinical results: Our results replicate several observations emanating from the literature demonstrating a diminution in the efficacy of descending pain inhibitory mechanisms (using a conditioned pain modulation paradigm; CPM) in subjects with chronic musculoskeletal pain (CP subjects). In these CP subjects, we also highlight a reduction in basal plasma concentrations of noradrenaline and metanephrine, when compared with pain-free subjects (PF subjects). For all tested subjects (PF and CP subjects), a positive association is observed between CPM efficacy and basal plasma concentrations of noradrenaline and metanephrine. Therefore, basal plasma catecholamines concentrations could be used as molecular indicators of the latent CPM efficacy. Conversely, no difference in monoaminergic activity and no association with CPM efficacy are observed when looking at the molecular content of cerebrospinal fluid. Preclinical results: Here, we expose a new double-hit model of pain in rodents (i.e., initial induction of a persistent pain [the 1st hit] and subsequent activation of descending pain modulatory mechanisms with tonic pain [the 2nd hit]). This experimental paradigm allows us to evaluate the efficacy of decending pain modulation in rodents in the context of chronic pain. Interestingly, we detect a reduction in the behavioral response to tonic pain (in the formalin test), 28 days after the induction of neuropathic pain (chronic constriction injury model; CCI), when compared to sham rats. Even though this reduction in nociceptive behaviors is still present 168 days after neuropathy, the effect seems to wane down over time. Concomitantly, in absence of tonic nociceptive stimulation, an elevation in central concentrations (i.e., cerebrospinal fluid) in serotonin and noradrenaline is observed 12 days after the induction of neuropathic pain, before returning to sham levels on day 28. Moreover, the behavioral response described on day 28 is only observed in a neuropathic pain model (CCI), and absent when inflammatory pain is used as the initial pain. Conclusions: In the context of chronic pain, our results in humans confirm the advent of modifications in the efficacy of descending pain inhibitory mechanisms, while supporting the emerging concept suggesting that individual differences in these mechanisms may be associated with individual differences in peripheral processes (such as the release of catecholamines in plasma), that could ultimately be involved in cardiovascular control. Moreover, our results in rodents suggest that dynamic changes (specific to pain types) in the efficacy of descending pain modulation, as well as in the central functionality of monoaminergic neurotransmission, are present during the progression of chronic pain. Overall, this thesis provides novel information concerning temporal neurophysiological changes in descending pain modulatory mechanisms that may be involved in the development and progression of chronic pain states.

O treinamento resistido (TR) de alta intensidade tem sido recomendado para reverter as alterações musculares promovidas pelo envelhecimento. Porém, o envelhecimento também se associa de aumento da pressão arterial (PA). Uma sessão de TR promove hipotensão pós-exercício em jovens, mas este efeito não está claro em idosos, sendo este o objetivo dessa dissertação. 16 idosos participaram, após 10-12 semanas de TR, de 2 sessões realizadas em ordem aleatória: Controle-C (repouso) e Exercício-E (3 séries, 8 RM, 7 exercícios). A PA, o débito cardíaco (DC), a freqüência cardíaca (FC), a modulação autonômica cardiovascular foram medidos pré e 60 min pós-intervenções e a PA ambulatorial foi medida por 24 h. A PA sistólica e média aumentaram na sessão C e não se modificaram na E, resultando num efeito hipotensor de -6,4±1,9 e -2,9±0,2 mmHg. A PA diastólica e a resistência vascular periférica (RVP) aumentaram de forma similar nas 2 sessões (+2,0±0,7 mmHg e +3,8±0,7 mmHg.min/l), enquanto que o DC e o volume sistólico (VS) diminuíram, e a FC, o duplo produto (DP) e a razão entre as bandas de baixa e alta freqüência da variabilidade do intervalo R-R aumentaram na sessão E (-0,5±0,1 l/min, -9,3±2,0 ml, +3,8±1,6 bpm, +579,3±164,1 mmHg/bpm e +0,71±0,35). Não houve diferença na PA de 24h, mas a FC e o DP permaneceram aumentados por 5,5 h pós-exercício. Assim, uma sessão de TR de alta intensidade teve efeito hipotensor em idosos treinados, que foi mediado pela redução do DC, promovida pela diminuição do VS, que não foi compensada apesar do aumento da FC, induzida pelo aumento da modulação simpática para o coração. O efeito hipotensor não perdurou pelas demais horas, mas o trabalho cardíaco ficou aumentado por até 5,5 h pós-exercício
High-intensity resistance training (RT) is recommended to delay the effects of aging on skeletal muscle. However, aging is also accompanied by blood pressure (BP) increases. Its known that each RT session promotes post-exercise hypotension in young, but this effect wasnt clear in elderly. Thus, this was the aim of the present study. 16 elderly subjects, who were already participating in a RT program, underwent, in a random order, 2 sessions: Control (C) remained seated and Exercise (E) 7 resistance exercises, 3 sets, 8 RM. BP, cardiac output (CO), heart rate (HR) and cardiovascular autonomic regulation were measured before and 60 min after interventions, while ambulatory BP was measured for 24 h. Systolic and mean BP increased in the C, but did not change in the E, resulting in a hypotensive effects of -6.4±1.9 and -2.9±0.2 mmHg, respectively. Diastolic BP and systemic vascular resistance (SVR) increased similarly in both sessions (+2.0±0.7 mmHg and +3.8±0.7 mmHg.min/l), while CO and stroke volume (SV) decreased, and HR, rate-pressure product (RPP) and low to high-frequency ratio of the R-R interval variability only increased in the E (-0.5±0.1l/min, -9.3±2.0ml/beat, +3.8±1.6beat/min, +579.3±164.1 mmHg/beat/min and +0.71±0.35). Ambulatory BP was similar in both sessions, but HR and RPP were increased for 5,5 h after exercise. In conclusion, a session of high-intensity RT promoted post-exercise hypotensive effects in trained elderly. This effect was mediated by a decrease in CO, produced by a reduction in SV that was not compensated besides the increase in HR, promoted by an increase in sympathetic modulation to the heart. The hypotensive effect was not sustained during daily activities, and cardiac work was kept sustained elevated for 5,5 h post-exercise

A hipotensão pós-exercício têm sido observada tanto após o exercício aeróbio quanto o resistido, porém o efeito desta associação não é conhecido. Este estudo verificou, o efeito agudo isolado e associado do exercício aeróbio e resistido na pressão arterial (PA) pós-exercício e nos seus mecanismos. 23 jovens submeteram-se a 4 sessões: controle(C); exercício aeróbio - 30 minutos em cicloergômetro em 75% do VO2 pico (A); c) exercício resistido; 6 exercícios, 3 séries de 20 repetições, 50% de uma repetição máxima (R) e; d) associação do exercício aeróbio e resistido (AR). Após as sessões de exercício, a PA sistólica, média e diastólica, diminuíram (AR=A) e o débito cardíaco (DC) reduziu de forma similar nas três sessões, enquanto que a resistência vascular periférica aumentou após as três sessões, mas o aumento foi maior na sessão AR. Nas três sessões de exercício o volume sistólico (VS) diminuiu e a freqüência cardíaca (FC) aumentou pelo aumento da modulação simpática e redução da parassimpática para o coração. Estas respostas foram maiores na sessão AR. Concluindo: o exercício A, R e AR promoveram hipotensão pós-exercício, devido à queda do DC, pela redução do VS. O exercício A foi o principal determinante desta resposta. A FC permaneceu elevada pós-exercício devido ao aumento da modulação simpática e redução da vagal para o coração, sendo estas respostas exacerbadas na sessão AR
Post-exercise hypotension has been observed after aerobic and resistance exercises, however the effect of the association of these exercises are unknown. This study verified the effect of aerobic and resistance exercise performed alone and in combination on post exercise blood pressure (BP), and its mechanisms. 23 young subjects were submitted to 4 sessions: control (C); aerobic exercise 30 minutes on cycle ergometer at 75% of the peak VO2 (A); c) resistance exercise; 6 exercises, 3 sets of 20 repetitions, 50% of one repetition maximum (R) and; d) association of aerobic and resistance exercises (AR). After exercise sessions, systolic, mean and diastolic BP decreased (AR=A), and cardiac output (CO) reduced similarly in the sessions. Systemic vascular resistance increased after the three exercise sessions, but this increase was greater in the AR session after all exercise sessions. Stroke volume (SV) decreased, while heart rate (HR) increased due to an increase in sympathetic and a decrease in vagal modulation to the heart. These responses were greater in the AR session. In conclusion: A, R and AR exercises promoted postexercise hypotension, due to a fall in the CO, with reduction in SV. Aerobic exercise xxi was the main determinant of this response. HR remained elevated after exercise bouts because the increase in sympathetic and reduction in the vagal modulation of the heart, and these responses were exacerbated in the AR session

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Hypertension is a multifactorial condition treated by pharmacological and complementary measures such as nutritional approach. In this context, Chia (Salvia hispanica L.) stands out for its nutritional, antioxidant and anti-inflammatory composition. However, it has not yet been elucidated if Chia can reduce blood pressure in hypertensive individuals, and which factors are responsible for this effect. In this context, the present study aimed to verify the effect of supplementation of chia (Salvia hispanica L.) on blood pressure and assess if oxidative stress, inflammation, endothelial function and cardiac autonomic modulation are factors associated with lowering blood pressure in hypertensive individuals treated or not. Thus, a double-blind, randomized controlled trial was conducted with 26 hypertensive individuals. Among these, seventeen treated individuals were randomized to consume chia (CHIA-MD n = 10) and placebo (PLA-MD n = 7). Another group of untreated hypertensive individuals was formed (CHIA-NM, n = 9). They consumed 35 g/day or placebo chia flour 12 weeks. Clinical and ambulatory blood pressure, cardiac autonomic modulation, oxidative stress, inflammation and a marker of nitric oxide production were measured at baseline and after intervention. While PLA-MD group showed no significant change in mean of clinic blood pressure (from 108.0±2.9 to 105.7±2.9 mmHg, p=0.70), it was observed this reduction in GHIA group (from 111.5±1.9 to 102.7±1.5 mmHg, p < 0.001) and CHIA-MD (from 111.3±2.2 to 100.1±1.8 mmHg, p < 0.001), it there was no significant reduction in CHIA-NM (111.7±2.9 para 105.7±2.9 mmHg, p=0.05). In CHIA group, blood pressure reduction was was due to the reduction in both systolic (146.2 ± 2.0 to 136.3 ± 2.6 mmHg, p <0.01) and diastolic components (94.2 ± 2.0 to 85.5 ± 1.2, p <0.001). The same results occurred in CHIA-MD (145.8 ± 2.2 to 133.7 ± 4.1 mmHg, p <0.01 and 94.3 ± 2.4 to 83.3 ± 1.3 mmHg, p <0.01) for systolic and diastolic components, respectively. CHIA-NM group had only reduced systolic blood pressure (146.8 ± 3.8 to 137.3 ± 3.1 mmHg, p <0.05). These reductions in clinical blood pressure were confirmed by ambulatory systolic blood pressure in all supplemented groups in periods of 24 hours, wakefulness and sleep. On the other hand, the ambulatory diastolic pressure did not change in either group. The hypotensive effects of chia were accompanied by reduction in lipid peroxidation in CHIA groups (p = 0.04) and Chia-NM (p = 0.02) compared to PLA-MD. The hypotensive effects of chia were accompanied by reduction in lipid peroxidation in CHIA (p = 0.04) and CHIA-NM (p = 0.02) compared to PLA-MD. CHIA group also showed a reduction of plasma nitrite (p = 0.02). Inflammation and cardiac autonomic modulation remained unchanged. It was concluded that consumption of chia flour is able to reduce blood pressure in hypertensive individuals treated or not, both clinically and ambulatory. This phenomenon was accompanied by reduced lipid peroxidation, but no alterations in inflammatory markers and cardiac autonomic modulation were seen.
A hipertensão arterial sistêmica é uma condição multifatorial que envolve em seu tratamento medidas farmacológicas e complementares, como as nutricionais. Nesse contexto, a Chia (Salvia hispanica L.) se destaca por sua composição nutricional, antioxidante e antiinflamatória. No entanto, ainda não foi elucidado se essa pode reduzir a pressão arterial de indivíduos hipertensos, e quais fatores são responsáveis por este efeito. Nesse contexto, o presente estudo objetivou verificar o efeito da suplementação de chia (Salvia hispanica L.) sobre a pressão arterial e avaliar se estresse oxidativo, inflamação, função endotelial e modulação autonômica cardíaca são fatores associados à redução da pressão arterial em hipertensos medicamentados ou não. Para tanto, um estudo duplo cego, randomizado com placebo controlado foi conduzido com 26 hipertensos. Destes, dezessete tratados medicamentosamente foram randomizados em grupos que consumiriam chia (CHIA-MD; n=10) e placebo (PLA-MD; n=7). Outro grupo de hipertensos não tratados medicamentosamente foi formado (CHIA-NM; n=9). Eles consumiram 35 g/dia de farinha de chia ou placebo durante 12 semanas. Pressão arterial clínica e ambulatorial, modulação autonômica cardíaca, estresse oxidativo, inflamação e marcador de produção de óxido nítrico foram mensurados no período basal e após intervenção. Enquanto o grupo PLA-MD não apresentou alteração significativa da pressão arterial média clínica (108,0±2,9 para 105,7±2,9 mmHg, p=0,70), observou-se esta redução no grupo CHIA (111,5±1,9 para 102,7±1,5 mmHg, p < 0,001) e CHIA-MD (111,3±2,2 para 100,1±1,8 mmHg, p < 0,001), mas sem que houvesse redução significativa em CHIA-NM (111,7±2,9 para 105,7±2,9 mmHg, p=0,05). No grupo CHIA, a redução da pressão média foi decorrente da redução tanto do componente sistólico (146,2±2,0 para 136,3±2,6mmHg, p<0,01) quanto diastólico (94,2±2,0 para 85,5±1,2, p<0,001). O mesmo ocorreu para o grupo CHIA-MD (145,8±2,2 para 133,7±4,1mmHg, p<0,01 e 94,3±2,4 para 83,3±1,3 mmHg, p<0,01) para os componentes sistólico e diastólico respectivamente. O grupo CHIA-NM obteve redução apenas da pressão sistólica (146,8±3,8 para 137,3±3,1 mmHg, p <0,05). Estas reduções de pressão arterial clínica foram confirmadas por redução da pressão ambulatorial sistólica em todos os grupos suplementados nos períodos de 24horas, vigília e sono. Por outro lado, a pressão ambulatorial diastólica não se alterou em nenhum dos grupos. Os efeitos hipotensores da chia foram acompanhados de redução na peroxidação lipídica nos grupos CHIA (p=0,04) e CHIA-NM (p=0,02) em comparação com o PLA-MD. O grupo CHIA, ainda apresentou redução de nitrito plasmático (p=0,02). Inflamação e modulação autonômica cardíaca mantiveram-se inalteradas. Conclui-se que o consumo de farinha de chia é capaz de reduzir a pressão arterial de hipertensos medicamentados ou não, tanto clinica quanto ambulatorialmente. Este fenômeno foi acompanhado pela redução da peroxidação lipídica, mas não de alteração nos marcadores inflamatórios e na modulação autonômica cardíaca.

Les instabilités aéroélastiques de bandes d’acier constituent aujourd’hui l’un des problèmes majeurs dans les sections de refroidissement par jets impactants des lignes de recuit continues.En effet, le traitement thermique des nouveaux aciers nécessite de très fortes pentes de température impliquant constamment des augmentations de vitesse de soufflage susceptibles de mettre en jeu des instabilités aéroélastiques. Des flottements ainsi que des divergences de bande ont déjà été constatées et identifiées. Ces deux instabilités impliquent dans la plupart des cas des chocs entre la bande et les buses de soufflage ce qui engendre des défauts de surface sur la bande.Un banc d’essai a été conçu et fabriqué dans le but d’analyser ces instabilités et d’anticiper leur apparition. A partir d’observations, la dynamique structurelle de la bande a été simplifiée à un mode de rotation rigide. Le banc comporte une plaque oscillante en mouvement forcé.Celle-ci est impactée par un dispositif de plusieurs jets axisymétriques turbulents ayant une disposition identique à celle des tours industrielles. Les efforts aérodynamiques stationnaires et instationnaires agissant sur la plaque sont mesurés au moyen de capteurs de pression.L’impact de plusieurs jets en interaction crée de très importants gradients de pression sur la plaque il est donc nécessaire que la grille de prises de pression soit très fine pour que l’estimation des efforts aérodynamiques soit correcte. La plaque est donc instrumentée de 91capteurs de pression sur une surface de 18 cm². Elle peut également être translatée dans les ois directions de l’espace, ce qui permet d’obtenir la distribution des efforts instationnaires ainsi que des coefficients aéroélastiques sur une grande surface de plaque et à différentes distances d’impact.Les mesures de pression stationnaires ont permis d’établir les courbes d’évolution des efforts d’impact des jets sur la plaque en fonction de la distance jet-plaque ainsi que de la géométrie des buses. Les résultats ont permis de déterminer la stabilité statique de la plaque en mouvement de pompage. Les mesures de vitesses des jets libres ont été effectuées paranémométrie à fil chaud et ont permis de déterminer leurs propriétés statistiques.Les mesures de coefficients aéroélastiques sur la plaque en rotation ont été effectuées surune seule géométrie de soufflage, pour différentes vitesses réduites. Les résultats mettent en évidence l’importance des effets de bords sur la stabilité de plaque. Des méthodes de post traitements ont proposées afin d’extrapoler les résultats à différentes largeurs de bande. Ils sont confrontés aux travaux de Regardin et al. (réf. [1]) et mettent en évidence des désaccords avec le cas réel. Des suggestions sont apportées afin d’améliorer la représentativité du banc vis-à-vis des bandes industrielles
Aeroelastic instabilities of steel strips impinged by arrays of cooling gas jets have becomeone of the main issues in cooling sections of continuous annealing lines. Indeed, the new steeltreatments require very high temperature variation rates which involve increases in jetvelocities that are likely to onset some aeroelastic instabilities. Strip flutter and divergencehave already been observed and identified. These two aeroelastic instabilities imply a strongrisk of contact with the blowing boxes, which can seriously blemish the strip.An experimental test rig was designed and built in order to analyze and predict of theseinstabilities. From observations, the strip’s structural dynamics was simulated by a rigidrotation mode. The rig included a forced oscillating plate which is impinged by an array ofaxisymmetric jets having the exact industrial geometry. The plate was instrumented withpressure sensors to measure the steady and unsteady surface pressures. The impingement ofinteracting jets creates very large pressure gradients on the plate and therefore a tight mesh ofpressure taps (91 over an 18cm² jet impingement surface) was necessary to allow a goodestimation of the aerodynamic loads The plate could also be moved in the three coordinatedirections as to obtain surface mappings of the unsteady jet forces and aeroelastic coefficientscan be obtained over a wide area and different jet-to-plate distances.The variation of the impinging aerodynamic forces was established as a function of the jetto-plate distance for different nozzle geometries. These results were used to determine the jetstatic stability in plunging motion. Velocity and turbulence measurements in free jets werecarried out using hot wire anemometry in order to determine their statistical properties.Aeroelastic coefficient measurements were carried out on the oscillating plate with onlyone nozzle geometry and different reduced velocities. Results show that the plate’s stability ismainly dependent on the boundary effects. Post processing methods are suggested in order toapply the results to larger plates. Results are compared to the data of Regardin et al. (réf. [1])and emphasize some discrepancies with respect to the real case. Finally some improvementsto the test-rig are suggested for it to be more representative of the industrial situation

Dans cette thèse, les propriétés d'une nanoparticule unique ont été réglée en modifiant son environnement.Plus spécifiquement, dans la première partie de ce travail, la résonance des plasmons de surface des nanobipyramides d'or individuelles a été étudié expérimentalement dans un milieu sous pression contrôlable et son évolution encadré par modélisations théoriques.Afin d'accéder à l'optique d'une nanoparticule unique tout en générant un environnement sous haute-pression, la combinaison de la spectroscopie par modulation spatial avec la cellule en enclume de diamant a été atteint.Dans la seconde partie de la thèse, les vibrations acoustiques des nanodisques d'or individuels sur a substrat en saphir ont été caractérisé expérimentalement via spectroscopie pump&probe. Une attention particulière a été accordée à leur amortissement en fonction du rapport d'aspect des disques en soulignant la présence des amplifications en factor de qualité.Modélisations numériques ont fourni un aperçu des amplifications observées, montrant que l'hybridations entre modes se produit pour rapport d'aspect spécifiques, potentiellement en atténuant les pertes en énergie acoustique à travers l'interface disque/substrat
In this thesis, the properties of a single nanoparticle have been tuned altering its environment. Specifically, in the first part of this work, the surface plasmon resonance of individual gold nanobipyramids has been experimentally studied under a pressure adjustable surrounding and its evolution physically framed thorough theoretical modeling.In order to access to the single nanoparticle optics while generating a hydrostatic high-pressure environment, a challenging combination of the spatial modulation spectroscopy technique with the diamond anvil cell method has been achieved.In the second part of the thesis, the acoustic vibrations of individual gold nanodisks on sapphire substrate has been experimentally characterized via pump&probe spectroscopy. Particular attention has been paid to their damping as a function of the disks aspect-ratio enlightening the presence of quality-factors enhancements.Numeric modeling has provided a physical insight for the observed amplifications, showing that modes hybridizations occur at specific aspect-ratios, potentially reducing the acoustic energy loss towards the interface disk/substrate

Uma sessão de exercício aeróbio provoca queda da pressão arterial (PA) e aumento da freqüência cardíaca (FC) pós-exercício. Diversos fatores, como a massa muscular, a intensidade e o gasto energético total do exercício podem influenciar esta resposta. Este estudo verificou as respostas pós-exercício da PA, da FC e de seus mecanismos, avaliando a influência dos fatores citados. Vinte e quatro jovens submeteram-se a quatro sessões: controle(C); exercício com um membro inferior (mmii) em 50% do VO2pico(E1); exercício com dois mmii em 50% do VO2pico (E2); e exercício com dois mmii com a mesma potência de E1(E2/1). As PA sistólica (PAS), média (PAM) e diastólica (PAD), o débito cardíaco (DC), a resistência vascular periférica (RVP), o volume sistólico (VS), a FC e a modulação autonômica cardíaca foram medidos. Após o exercício, a PAS e o DC diminuíram e a RVP aumentou em E2. A PAD e PAM não se alteraram. A FC aumentou e o VS e o componente de alta freqüência da variabilidade da FC diminuíram em E1 e E2 (maior em E2). Concluindo: o exercício aeróbio promove hipotensão pós-exercício, devido à queda do DC pela redução do VS. O gasto energético total do exercício é o principal determinante desta resposta. A FC permanece elevada pós-exercício devido ao retardo da reativação vagal. A intensidade e o gasto energético do exercício são os principais determinantes desta resposta
A single bout of aerobic exercise reduces blood pressure (BP) and increases heart rate (HR) during the recovery period. Many factors, such as exercise intensity, muscle mass and total energy expenditure might influence this response. This study verified post-exercise responses of BP, HR and their mechanisms, evaluating the influence of previous factors. Twenty-four subjects underwent four sessions: control (C); exercise with one leg at 50% of VO2peak (E1); exercise with two legs at 50% of VO2peak (E2); and exercise with two legs and the same workload employed in E1 (E2/1). Systolic, mean, and diastolic BPs (SBP, MBP, DBP), systemic vascular resistance (SVR), cardiac output (CO), stroke volume (SV), HR, and cardiac autonomic modulations were measured before and after interventions. After exercise, SBP and CO decreased, while SVR increased in E2. DBP and MBP did not change. HR increased, while SV and the high frequency band of HR variability decreased in E1 and E2 (more in E2). In conclusion: aerobic exercise produced post-exercise hypotension by a decrease in CO, via a decrease in SV. This response is determined by the exercise total energy expenditure. HR is elevated after exercise due to a delay in the restoration of vagal activity to the heart. Exercise intensity and total energy expenditure influence this response. Key-words: aerobic exercise, muscle mass, total energy expenditure, relative intensity, blood pressure, heart rate, autonomic modulation

Introdução: A osteoartrite de joelhos (KOA) apresenta alta prevalência, principalmente em mulheres. Com o envelhecimento da população esta prevalência irá aumentar. Os tratamentos conservadores apresentam limitada eficácia em expressivo número de pacientes no curso do tratamento . A cirurgia de protetização apresenta altos custos, possibilidade de complicações pós-operatórias graves e ainda que a correção anatômica seja perfeita, em torno de 20% dos pacientes persistem com dor crônica pós-operatória. Portanto, é preciso avançar no conhecimento dos mecanismos fisiopatológicos e estudar novas abordagens terapêuticas para agregar às existentes, visando melhor manejo da dor e para restabelecer a função de maneira mais efetiva. Estas questões motivaram três questões centrais que origiram os três estudos que compõem esta tese. Estudo I: No primeiro estudo avaliamos os mecanismos pelos quais há perpetuação da dor na KOA. Para responder a esta questão buscou respostas aos seguintes objetivos: I) Comparar se a função da via da dor inibitório descendente está associada com o estado de inibição no sistema corticospinal, indexado pelo potencial evocado motor (MEP) e o período de silêncio cortical (CSP) em pacientes com KOA e controles saudáveis. II) Determinar se há correlação entre as medidas de inibição intracortical (CSP, MEP) com alterações na escala de dor numérica (NPS 0-10) na KOA durante a tarefa de modulação condicionada de dor (CPM-task) considerando o efeito da capacidade funcional auto-relatada avaliada pelo Western Ontário and McMaster Universities Index (WOMAC) e uso de analgésicos. Métodos: Estudo transversal, foram incluídas 21 pacientes femininas com KOA e 10 controles saudáveis com idade entre 19 a 75 anos. Os parâmetros de excitabilidade do córtex motor (MEP e CSP) foram avaliados utilizando a estimulação magnética trasncraniana (EMT). Avaliação de dor e a incapacidade pelo WOMAC e a NPS (0-10) durante a CPM-task. Resultados: A média ajustada (DP) do CSP observada em pacientes com OA foi 23,43% menor do que em indivíduos saudáveis [54,54 (16,10) vs. 70,94 (22,87)], respectivamente (P = 0,01). A função do sistema modulador descendente de dor avaliado pela alteração do NPS (0-10) durante o CPM-task foi negativamente correlacionada com o parâmetro de excitabilidade cortical indexado pelo CSP (P = 0,001). O CSP foi negativamente correlacionado com a dor e incapacidade avaliada pelo índice WOMAC. Conclusão: Foi observado um sistema inibitório descendente de dor enfraquecido, corroborando com os achados em outras patologias de dor crônica. Estudo II O segundo estudo buscou determinar se na KOA, uma sessão de IMS (eletroestimulação intramuscular) ativa comparada com sham promove um efeito nos parâmetros de excitabilidade do córtex motor [MEP, inibição intracortical curta - SICI, facilitação intracortical (ICF) e CSP] e nas medidas de dor [limiar de dor a pressão (PPT); escala visual analógica de dor (VAS) e mudança na escala de dor numérica (NPS0-10) durante a CPM-task]. Esse estudo também se propôs a determinar se o fator neurotrófico derivado do cérebro (BDNF) sérico medeia o efeito desta estimulação no sistema cortico-espinhal, tal como avaliado pelo MEP e pelo PPT. Métodos: Foram incluídas 26 mulheres com KOA, com idade entre 50 a 75 anos. Elas foram divididas randomicamente para receber uma sessão de 30 minutos de IMS ativa (n = 13) ou IMS sham (n = 13) por meio de eletroestimulação com frequência de 2 Hz. As agulhas foram inseridas paravertebrais em nível da saída das raízes lombares de L1 a S2 e nos músculos cuja inervação corresponde a essas raízes e que sustentam a articulação do joelho (vasto medial, reto anterior, vasto lateral, tibial anterior e inserção da pata anserina). Os desfechos foram as medidas de dor (VAS, PPT, NPS durante CPM-task) e parâmetros de excitabilidade (MEP, CSP, SICI, ICF) realizados antes e imediatamente após a intervenção. Resultados: a IMS ativa comparado com sham diminuiu o MEP em 31,61% [intervalo de confiança (IC) 95%, 2,34-60,98]. Para os resultados secundários, IMS reduziu o ICF e aumentou o CSP. A IMS melhorou a dor relatada no VAS, o PPT e a pontuação do NPS (0-10) durante a CPM-task. O BDNF foi negativamente correlacionado com o PPT (r = 20,56). Conclusão: Obtivemos resultados demonstrando melhora da dor e reforço do sistema cortico-espinhal inibitório comparado ao tratamento sham com IMS. Estudo III O terceiro estudo buscou: 1) Avaliar se a utilização da ETCC (estimulação transcraniana de corrente contínua) combinada a IMS pode promover um resultado melhor de modulação da via cortico-espinhal de dor através da potenciação dos efeitos dos dois tratamentos; comparado a cada um deles isoladamente e ao tratamento sham. 2) Avaliar a capacidade da ETCC em reforçar o sistema inibitório descendente de dor e modular a excitabilidade neuronal através da VAS, PPT e NPS durante CPM-task. Além disso, avaliamos se o BDNF sérico poderia prever o efeito da terapia no final do tratamento. Métodos: 60 mulheres de 50 a 75 anos. Randomizadas em um de quatro grupos: ETCC+IMS, ETCC+IMS sham, ETCC sham+IMS, ETCC sham+IMS sham. Receberam 5 sessões de tratamento: ETCC anodal, lado contrário ao joelho acometido, 2mA, 30 min. IMS: estimulação com freqüência de 2Hz, 30 min; agulhas colocadas a 2cm de L1 á S2, nos músculos vasto medial, vasto lateral, reto anterior, tibial anterior e na inserção da pata anserina. Resultados: O a-tDCS + a-IMS mostrou os melhores resultados com diferença significativa na dor (VAS) [média (DP) relacionadas ao tratamento (pós e pré): 0.46 (0.04) vs. 6.32 (1.97); 95%CI -5.42 (-8.24 to -4.36), p=.003] e funcionalidade. Esse resultado iniciou na primeira sessão e manteve-se ao longo do estudo. A-tDCS+a-IMS foi o único capaz de modificar o sistema inibitório descendente de dor. Conclusão: Obtivemos melhora da dor e capacidade funcional com IMS, ETCC e ETCC+IMS. Mas somente o grupo de tratamento ETCC+IMS demonstrou capacidade de modificação do sistema inibitório descendente de dor.
Background: Knee osteoarthritis (KOA) has a high prevalence, especially in women. With the aging of the population this prevalence will increase. Conservative treatments have limited efficacy in expressive number of patients in the course of the treatment. The total knee replacement surgery presents high costs, possibility of serious postoperative complications and although the anatomical correction is perfect, around 20% persist with chronic postoperative pain. Therefore, it’s necessary to advance in the knowledge of pathophysiological mechanisms and to study new therapeutic approaches to add to the existing ones, aiming to better manage pain and to restore function more effectively. These questions motivated three central questions that originated the three studies that compose this thesis. Study I In the first study we evaluated the mechanisms by which there is perpetuation of pain in knee osteoarthritis and to answer this question sought to answer the following objectives: I) To compare if the function of the descending inhibitory pain pathway is associated with the state of inhibition in the corticospinal system, indexed by the motor evoked potential (MEP) and the cortical silent period (CSP) in patients with KOA and healthy controls. II) To determine if there is a correlation between the intracortical inhibition measures (CSP, MEP) with changes in the numerical pain scale (NPS 0-10) in the KOA during the task of conditioned pain modulation (CPM-task) considering the effect of the self-reported function evaluated by the Western Ontario and McMaster Universities Index (WOMAC) and the use of analgesics. Methods: A cross-sectional study included 21 female patients with KOA and 10 healthy controls aged 19-75 years old. Motor cortex excitability parameters (MEP and CSP) were assessed using transcranial magnetic stimulation (TMS). Pain assessment and disability by WOMAC and NPS (0-10) during the CPM-task. Results: The adjusted mean (SD) of CSP observed in patients with OA was 23.43% lower than in healthy subjects [54,54 (16,10) vs 70.94 (22.87)], respectively (P = 0.01). The function of the descending pain modulatory system evaluated by the NPS (0-10) change during the CPM-task was negatively correlated with the cortical excitability parameter indexed by CSP (P = 0.001). CSP was negatively correlated with pain and disability assessed by the WOMAC index. Conclusion: It was observed a descending pain inhibitory system weakened, corroborating the findings of other chronic pain conditions. Study II The second study sought to determine if one active IMS session compared to sham promoted an effect on motor cortex excitability (MEP, short intracortical inhibition - SICI, intracortical facilitation (ICF) and CSP and in the pain measures [pressure pain threshold (PPT); Visual analogue pain scale (VAS) and numerical pain scale change (NPS0-10) during the CPM-task]. This study also aimed to determine whether serum brain-derived neurotrophic factor (BDNF) mediates the effect of this stimulation on the cortico-spinal system, as assessed by MEP and PPT. Methods: Twenty-six women with KOA, aged 50-75 years old, were included. They were randomly divided to receive a 30-minute session of active IMS (n = 13) or IMS sham (n = 13) by electrostimulation with a frequency of 2 Hz. The needles were inserted paravertebral at the level of the lumbar roots exit from L1 to S2 and in the muscles whose innervation corresponds to these roots and which support the knee joint (vastus medialis, rectus anterior, vastus lateral, tibialis anterior and insertion of the anserine paw). The outcomes were pain measures (VAS, PPT, NPS during CPM-task) and excitability parameters (MEP, CSP, SICI, ICF) performed before and immediately after the intervention. Results: the active IMS compared with sham decreased the MEP by 31.61% [confidence interval (CI) 95%, 2.34-60.98]. For the secondary outcomes, IMS reduced ICF and increased CSP. IMS improved pain reported in VAS, PPT, and NPS score (0-10) during the CPM-task. BDNF was negatively correlated with PPT (r = 20.56). Conclusion: We obtained results demonstrating improvement of pain and enhancement of the inhibitory corticospinal system compared to sham treatment with IMS. Study III The third study aimed to: 1) Evaluate if the use of the combined tDCS (transcranial direct current stimulation) to IMS can promote a better result of modulation of the corticospinal pain pathway through the potentiation of the effects of the two treatments; compared to each of them alone, and with the sham treatment. 2) To evaluate the ability of the tDCS to strengthen the descending inhibitory pain system and to modulate neuronal excitability through VAS, PPT and NPS during CPM-task. In addition, we evaluated whether serum BDNF could predict the effect of therapy at the end of treatment. Methods: 60 women aged 50 to 75 years old. Randomized in one of four groups: tDCS + IMS, tDCS + IMS sham, tDCS sham + IMS, tDCS sham + IMS sham. They received 5 sessions of treatment: anodal tDCS, opposite side to affected knee, 2mA, 30 min. IMS: stimulation with frequency of 2Hz, 30 min; needles placed at 2 cm from L1 to S2, in the vastus medialis, vastus lateralis, rectus anterior, tibialis anterior and insertion of the anserine paw. Results: a-tDCS + a-IMS showed the best results with significant difference in pain (VAS) [mean (SD) related to treatment (post and pre): 0.46 (0.04) vs. 6.32 (1.97); 95% CI -5.42 (-8.24 to -4.36), p = .003] and functionality. This result started in the first session and was maintained throughout the study. A-tDCS + a-IMS was the only one able to modify the descending inhibitory pain system. Conclusion: We achieved improved pain and functional capacity with IMS, tDCS and tDCS + IMS. But only the tDCS + IMS treatment group demonstrated ability to modify the descending inhibitory pain system.