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Simple Summary: The regulation of oxidative stress at rest and in response to a single session of exercise is vital for cardiovascular and metabolic health. However, the lack of regular physical activity and exercise and the presence of obesity are known to negatively impact oxidative stress under both conditions. In the present study, the oxidative stress response in circulation and within exosome-like extracellular vesicles (ELVs) released by contracting skeletal muscle during exercise was examined following maximal intensity treadmill running. As a result, we demonstrate that aerobically untrained individuals with obesity exhibit an altered oxidative stress response to maximal treadmill running compared to aerobically untrained and aerobically trained individuals without obesity. Similarly, body mass index, an index of obesity, but not cardiorespiratory fitness, was associated with an adverse oxidative response at rest and immediately following maximal treadmill running. These findings suggest that obesity, more than improved cardiorespiratory fitness, differentially regulates plasma and circulating ELV indices of oxidative stress prior to and immediately following acute maximal treadmill exercise. The impact of cardiorespiratory fitness (VO2max) and obesity on indices of oxidative stress in plasma and circulating exosome-like extracellular vesicles (ELVs) were examined following acute exercise. Indices of oxidative stress in plasma and isolated plasma ELVs were examined in aerobically trained (NW-Tr; n = 15) and untrained (NW-UTr; n = 18) normal-weight individuals and aerobically untrained individuals with obesity (Ob-Utr; n = 10) prior to and immediately following acute maximal treadmill running. Following exercise, ELV flotillin-1 expression (p = 0.008) and plasma total antioxidant capacity (TAC; p = 0.010) increased more in NW-UTr compared to NW-Tr and Ob-UTr participants, whereas plasma protein carbonyls (PC) decreased more in Ob-UTr compared to NW-Tr and NW-UTr groups. ELV glutathione (GSH) concentrations decreased more in NW-Tr compared to NW-UTr and Ob-UTr participants (p = 0.009), whereas lipid peroxidase (LPO) concentrations increased more in Ob-UTr compared to NW-Tr and NW-UTr participants (p = 0.003). Body mass index (BMI) was associated negatively with plasma TAC and PC (p < 0.05) and positively with ELV LPO concentration responses (p = 0.009). Finally, plasma-to-total (plasma + ELV) GSH ratios decreased in Ob-UTr compared to NW-Tr and NW-UTr participants (p = 0.006), PC ratios increased in NW-Tr and NW-UTr compared to Ob-UTr subjects (p = 0.008), and reactive oxygen/nitrogen species ratios increased in NW-UTr and decreased in Ob-UTr participants (p < 0.001). BMI, independently of VO2max, differentially regulates indices of oxidative stress within plasma and circulating ELVs prior to and immediately following acute maximal treadmill exercise. [ABSTRACT FROM AUTHOR]

Pentraxin 3 (PTX3), a cardioprotective protein, has recently been shown to be associated with improved insulin resistance (IR) and glucose metabolism. Therefore, the primary purpose of this study was to examine whether or not increased plasma PTX3 following maximal aerobic exercise would differ between obese and normal-mass subjects, and its association with the homeostatic model assessment of insulin resistance (HOMA-IR) and glucose response. Twenty-five untrained obese (n = 13 [6 males and 7 females]) and normal-mass (n = 12 [5 males and 7 females]) subjects performed an acute bout of maximal aerobic exercise to assess maximal oxygen consumption ([VO.sub.2max]). At baseline, plasma PTX3 concentrations are decreased in obese compared with normal-mass subjects and are negatively associated with plasma insulin and HOMA-IR values. In response to maximal exercise, plasma PTX3 responses were similar in obese and normal-mass subjects while the intensity of plasma PTX3 response as indicated by area under the curve analysis (AUCi) was not associated with HOMA-IR or glucose AUCi. However, PTX3 AUCi was positively associated with cardiorespiratory fitness levels (relative [VO.sub.2max]). These findings suggest that PTX3 could serve as a biomarker for both metabolic health, as well as a measurement to monitor the effectiveness of exercise interventions in obesity. Key words: pentraxin 3, obesity, aerobic exercise, insulin resistance, cardiorespiratory fitness. On a montre recemment que la pentraxine 3 (PTX3), une proteine dotee de proprietes de cardioprotection, est associee a des ameliorations sur le plan de la resistance a l'insuline (IR) et du metabolisme du glucose. Par consequent, le principal objectif des presents travaux etait d'evaluer si l'augmentation des taux plasmatiques de PTX3 apres un effort physique aerobie maximal serait differente chez les sujets obeses comparativement aux sujets dont le poids est normal, et si cette observation serait associee a des modifications sur le plan de l'homeostasie de la resistance a l'insuline (ou HOMA-IR pour << homeostatic model assessment of insulin resistance >>) et de la reponse glycemique. Pour ce faire, 25 sujets non entraines obeses (n = 13 [6 hommes et 7 femmes]) et de poids normal (n = 12 [5 hommes et 7 femmes]) ont effectue un effort physique aerobie maximal intense en vue d'evaluer la consommation maximale d'oxygene ([VO.sub.2max]). Au debut de l'etude, les concentrations plasmatiques de PTX3 etaient plus basses chez les sujets obeses que chez les sujets de poids normal et inversement proportionnelles aux taux d'insuline plasmatique et aux valeurs de l'HOMA-IR. En reponse a l'effort physique maximal, les taux plasmatiques de PTX3 observes etaient semblables dans les 2 groupes, et l'aire sous la courbe << en ce qu'elle concerne l'augmentation des taux >> (ASCa) n'etait pas associee a l'ASCa des valeurs de l'HOMA-IR ni de la reponse glycemique. Cependant, l'ASCa des taux de PTX3 etait proportionnelle au degre de forme physique dont le [VO.sub.2max] temoignait. Ces observations semblent indiquer que la PTX3 pourrait etre utile comme biomarqueur de la sante metabolique ainsi que pour evaluer l'efficacite de l'entrainement physique en presence d'obesite. [Traduit par la Redaction] Mots-cles : pentraxine 3, obesite, effort physique aerobie, resistance a l'insuline, forme cardiorespiratoire., Introduction Obesity is characterized as a chronic state of low-grade proinflammation by the enlargement of adipocytes and increased infiltration of circulating monocytes differentiated into resident adipose tissue macrophages (Weisberg et [...]

In this paper, the tool-tip responses for ball end milling, due to the coupling effects of a flexible rotor-bearing system, are investigated numerically. The milling machine tool spindle is modelled as the flexible rotor-bearing system. The critical speeds, natural modes, and unbalance responses of the system are calculated by applying the generalized polynomial expansion method. This generalized polynomial expansion method expresses the displacement as a series formed by the product of generalized coordinates and axial coordinate polynomials. According to the dynamic cutting force obtained by some scholars in the past, combined with the characteristics of the flexible rotor, the dynamic response of the tool-tip for ball end milling is numerically analyzed. The responses, including time histories, orbits, and FFT diagrams, are plotted to analyze the dynamic behaviors of the tool-tip. The coupling effects of the flexible rotor-bearing system on the system for ball end milling are first studied using the generalized polynomial expansion method. Unlike previous studies, the natural frequency varies with spindle speed and which of the different modes are included in the tool-tip response depends mainly on the spindle speed. Thanks to the gyroscopic effect, the critical speeds and responses of tool-tips can be discussed with respect to various spindle speed and tool flutes. The natural modes are accurately determined, and will excite critical speeds for certain modes, including forward and backward modes, thereby significantly affecting tool-tip response. In addition, the cutting force component associated with the tool-tip response affects the rotor-bearing system parameters, complicating the issue. Milling at higher spindle speed (2160–19,950 rpm), an important new result is found that the tool-tip oscillates with the cutting-force frequency, accompanied by a longer period vibration of the first backward mode of the rotor-bearing system. It can also be seen from the frequency spectrum analysis that, as the spindle speed increases, the peak amplitude of the first backward mode becomes larger. Milling at lower spindle speed (960, 1320 rpm), the in-plane vibration trajectory of the tool-tip gradually expands outwards clockwise around the origin until a stable loop is reached. This is because only the first backward mode of the rotor-bearing system is excited. Considering the coupling effect of the rotor-bearing system to perform the vibration analysis of the milling machine system, the parameters of the system can be designed or the spindle speed can be selected to avoid severe vibration during machining. [ABSTRACT FROM AUTHOR]