Articoli di riviste: "Aerobic limitation"

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Walker, Timothy J., Jessica M. Tullar, Pamela M. Diamond, Harold W. Kohl e Benjamin C. Amick. "The Relation of Combined Aerobic and Muscle-Strengthening Physical Activities With Presenteeism". Journal of Physical Activity and Health 14, n. 11 (1 novembre 2017): 893–98. http://dx.doi.org/10.1123/jpah.2016-0696.

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Background: There is a need to understand physical activity types associated with health-related work limitations (also known as presenteeism). This study tests whether additive effects between physical activity types are associated with health-related work limitations among employees from a public university system. Methods: A cross-sectional study using health assessment data (n = 10,791) was used to examine aims. Analysis of covariance models tested differences in work limitations between physical activity groups based on combinations of stretching behavior, aerobic, and muscle-strengthening physical activities. Planned contrasts compared differences between selected groups. Results: There were significant group differences (P < .001) in reported work limitations after controlling for demographic, season, and health-related variables. Employees who reported participating in aerobic physical activity had significantly lower work limitation levels compared with inactive employees (P = .027). Employees who reported participating in both aerobic and muscle-strengthening physical activities had the lowest work limitation levels compared with all groups and significantly lower work limitation levels compared with employees who participated in aerobic physical activity only (P = .026). Conclusions: Results provide evidence of an additive effect where participating in a combination of aerobic and muscle-strengthening physical activities may be most beneficial when targeting health-related work limitations.

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Fredlund, Elisabeth, Lars M. Blank, Johan Schnürer, Uwe Sauer e Volkmar Passoth. "Oxygen- and Glucose-Dependent Regulation of Central Carbon Metabolism in Pichia anomala". Applied and Environmental Microbiology 70, n. 10 (ottobre 2004): 5905–11. http://dx.doi.org/10.1128/aem.70.10.5905-5911.2004.

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ABSTRACT We investigated the regulation of the central aerobic and hypoxic metabolism of the biocontrol and non-Saccharomyces wine yeast Pichia anomala. In aerobic batch culture, P. anomala grows in the respiratory mode with a high biomass yield (0.59 g [dry weight] of cells g of glucose−1) and marginal ethanol, glycerol, acetate, and ethyl acetate production. Oxygen limitation, but not glucose pulse, induced fermentation with substantial ethanol production and 10-fold-increased ethyl acetate production. Despite low or absent ethanol formation, the activities of pyruvate decarboxylase and alcohol dehydrogenase were high during aerobic growth on glucose or succinate. No activation of these enzyme activities was observed after a glucose pulse. However, after the shift to oxygen limitation, both enzymes were activated threefold. Metabolic flux analysis revealed that the tricarboxylic acid pathway operates as a cycle during aerobic batch culture and as a two-branched pathway under oxygen limitation. Glucose catabolism through the pentose phosphate pathway was lower during oxygen limitation than under aerobic growth. Overall, our results demonstrate that P. anomala exhibits a Pasteur effect and not a Crabtree effect, i.e., oxygen availability, but not glucose concentration, is the main stimulus for the regulation of the central carbon metabolism.

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Garayburu-Caruso, Vanessa A., James C. Stegen, Hyun-Seob Song, Lupita Renteria, Jaqueline Wells, Whitney Garcia, Charles T. Resch et al. "Carbon Limitation Leads to Thermodynamic Regulation of Aerobic Metabolism". Environmental Science & Technology Letters 7, n. 7 (15 maggio 2020): 517–24. http://dx.doi.org/10.1021/acs.estlett.0c00258.

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Sperandio, Evandro F., Anderson S. Alexandre, Liu C. Yi, Patrícia R. Poletto, Alberto O. Gotfryd, Milena C. Vidotto e Victor Z. Dourado. "Functional aerobic exercise capacity limitation in adolescent idiopathic scoliosis". Spine Journal 14, n. 10 (ottobre 2014): 2366–72. http://dx.doi.org/10.1016/j.spinee.2014.01.041.

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Chen, Guang Hao, Wun Jern Ng, Hiroaki Ozaki e Yutaka Terashima. "Determination of dissolved oxygen limitation in aerobic biofilm reactors". Resources, Conservation and Recycling 11, n. 1-4 (giugno 1994): 73–81. http://dx.doi.org/10.1016/0921-3449(94)90079-5.

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Chen, Guang Hao. "Prediction of oxygen limitation in an aerobic biofilm reactor". Journal of Environmental Science and Health . Part A: Environmental Science and Engineering and Toxicology 31, n. 10 (novembre 1996): 2465–75. http://dx.doi.org/10.1080/10934529609376503.

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Suyama, Tetsushi, Toru Shigematsu, Toshihiko Suzuki, Yutaka Tokiwa, Takahiro Kanagawa, Kenji V. P. Nagashima e Satoshi Hanada. "Photosynthetic Apparatus in Roseateles depolymerans 61A Is Transcriptionally Induced by Carbon Limitation". Applied and Environmental Microbiology 68, n. 4 (aprile 2002): 1665–73. http://dx.doi.org/10.1128/aem.68.4.1665-1673.2002.

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ABSTRACT Production of a photosynthetic apparatus in Roseateles depolymerans 61A, a recently discovered freshwater β-Proteobacterium showing characteristics of aerobic phototrophic bacteria, was observed when the cells were subjected to a sudden decrease in carbon sources (e.g., when cells grown with 0.1 to 0.4% Casamino Acids were diluted or transferred into medium containing ≤0.04% Casamino Acids). Accumulation of bacteriochlorophyll (BChl) a was observed in the presence of oxygen and was enhanced under semiaerobic conditions (2% oxygen) but was reduced in the presence of light. Similarly to what has been reported regarding some aerobic phototrophic bacteria belonging to the α subclass of the Proteobacteria, viability of the cells in the carbon source-free medium was prolonged under aerobic-light (10 W m−2) conditions, possibly due to photosynthetic energy conversion, but was not prolonged under aerobic-dark conditions. The puf operon, which encodes most of the apoproteins of light-harvesting and reaction center complexes, was sequenced, and the effect of changes in Casamino Acids concentrations, oxygen, and light on its expression was estimated by the accumulation of its mRNA. The expression of the puf operon was induced by the decrease in carbon sources, similarly to what was observed for the accumulation of BChl a under aerobic and semiaerobic conditions (≥0.2% O2), and was reduced in the presence of light. Transcription of the R. depolymerans puf operon is considered to be controlled by changes in carbon nutrients in addition to oxygen tension and light intensity.

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Bradley, J. A., S. Arndt, J. P. Amend, E. Burwicz, A. W. Dale, M. Egger e D. E. LaRowe. "Widespread energy limitation to life in global subseafloor sediments". Science Advances 6, n. 32 (agosto 2020): eaba0697. http://dx.doi.org/10.1126/sciadv.aba0697.

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Microbial cells buried in subseafloor sediments comprise a substantial portion of Earth’s biosphere and control global biogeochemical cycles; however, the rate at which they use energy (i.e., power) is virtually unknown. Here, we quantify organic matter degradation and calculate the power utilization of microbial cells throughout Earth’s Quaternary-age subseafloor sediments. Aerobic respiration, sulfate reduction, and methanogenesis mediate 6.9, 64.5, and 28.6% of global subseafloor organic matter degradation, respectively. The total power utilization of the subseafloor sediment biosphere is 37.3 gigawatts, less than 0.1% of the power produced in the marine photic zone. Aerobic heterotrophs use the largest share of global power (54.5%) with a median power utilization of 2.23 × 10−18 watts per cell, while sulfate reducers and methanogens use 1.08 × 10−19 and 1.50 × 10−20 watts per cell, respectively. Most subseafloor cells subsist at energy fluxes lower than have previously been shown to support life, calling into question the power limit to life.

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Strubbe, Laurence, Margot Pennewaerde, Janis E. Baeten e Eveline I. P. Volcke. "Continuous aerobic granular sludge plants: Better settling versus diffusion limitation". Chemical Engineering Journal 428 (gennaio 2022): 131427. http://dx.doi.org/10.1016/j.cej.2021.131427.

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Karsten, Marlus, Laura Maria Tomazi Neves, Victor Ribeiro Neves, Thomas Beltrame, Audrey Borghi-Silva, Ross Arena, Piergiuseppe Agostoni e Aparecida Maria Catai. "Recent myocardial infarction patients present ventilatory limitation during aerobic exercise". International Journal of Cardiology 161, n. 3 (novembre 2012): 180–81. http://dx.doi.org/10.1016/j.ijcard.2012.06.026.

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Hammond, K. A., M. A. Chappell, R. A. Cardullo, R. Lin e T. S. Johnsen. "The mechanistic basis of aerobic performance variation in red junglefowl". Journal of Experimental Biology 203, n. 13 (1 luglio 2000): 2053–64. http://dx.doi.org/10.1242/jeb.203.13.2053.

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We examined aerobic performance, organ and muscle mass and enzymatic activity in red junglefowl (Gallus gallus). We tested three models of performance limitation (central limits, peripheral limits, symmorphosis) and explored relationships between basal metabolic rate (BMR), aerobic capacity (V (O2max)) and social rank. Males had a lower BMR, a higher V (O2max) and a greater aerobic scope than females. Females possessed larger peritoneal and reproductive organs, while males had larger hearts, lungs and leg muscles. In females, BMR was correlated with spleen mass and V (O2max) was correlated with hematocrit and large intestine mass. Male BMR was correlated with intestinal tract and lung mass, and V (O2max) was correlated with heart and pectoralis mass. Male citrate synthase activity averaged 57 % higher than that of females and was correlated with V (O2max) (this correlation was not significant in females). Female social status was not correlated with any variable, but male dominance was associated with higher aerobic scope, larger heart and lungs, smaller peritoneal organs and greater leg citrate synthase activity. We conclude that aerobic capacity is controlled by system-wide limitations (symmorphosis) in males, while in females it is controlled by central organs. In neither sex is elevated aerobic capacity associated with increased maintenance costs.

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Manché, Karen, Lucinda Notley-McRobb e Thomas Ferenci. "Mutational Adaptation of Escherichia coli to Glucose Limitation Involves Distinct Evolutionary Pathways in Aerobic and Oxygen-Limited Environments". Genetics 153, n. 1 (1 settembre 1999): 5–12. http://dx.doi.org/10.1093/genetics/153.1.5.

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Abstract Mutational adaptations leading to improved glucose transport were followed with Escherichia coli K-12 growing in glucose-limited continuous cultures. When populations were oxygen limited as well as glucose limited, all bacteria within 280 generations contained mutations in a single codon of the ptsG gene. V12F and V12G replacements in the enzyme IIBCGlc component of the glucose phosphotransferase system were responsible for improved transport. In stark contrast, ptsG mutations were uncommon in fully aerobic glucose-limited cultures, in which polygenic mutations in mgl, mlc, and malT (regulating an alternate high-affinity Mgl/LamB uptake pathway) spread through the adapted population. Hence the same organism adapted to the same selection (glucose limitation) by different evolutionary pathways depending on a secondary environmental factor. The clonal diversity in the adapted populations was also significantly different. The PtsG V12F substitution under O2 limitation contributed to a universal “winner clone” whereas polygenic, multiallelic changes led to considerable polymorphism in aerobic cultures. Why the difference in adaptive outcomes? E. coli physiology prevented scavenging by the LamB/Mgl system under O2 limitation; hence, ptsG mutations provided the only adaptive pathway. But ptsG mutations in aerobic cultures are overtaken by mgl, mlc, and malT adaptations with better glucose-scavenging ability. Indeed, when an mglA::Tn10 mutant with an inactivated Mgl/LamB pathway was introduced into two independent aerobic chemostats, adaptation of the Mgl– strain involved the identical ptsG mutation found under O2-limited conditions with wild-type or Mgl– bacteria.

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Leal, Juliane Barroso, Juçara Barroso Leal, Joaline Barroso Portela Leal, Yan de Lima Borges, Maria Ivone Leal de Moura, Alfredo Anderson Teixeira-Araujo, Venilson Serafim da Costa e Ferdinando Oliveira Carvalho. "Grape juice and aerobic exercise on blood pressure". Nutrition & Food Science 50, n. 5 (19 dicembre 2019): 987–98. http://dx.doi.org/10.1108/nfs-08-2019-0256.

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Purpose This paper aims to verify the effect of 12 weeks of grape juice (GJ) consumption associated with aerobic exercise on the variation of the hypertensive elderly pressure. Design/methodology/approach A total of 45 hypertensive elderly of both sexes were distributed into: control group (CG, n = 10), exercise group (EG, n = 10), juice group (JG, n = 12) and juice and exercise group (JEG, n = 13). Blood pressure and heart rate were checked weekly before exercise in JG and JEG, and before and after intervention in all groups, with JG and JEG supplemented with 200 mL of GJ. Three weekly sessions of moderate walking were applied. Findings There was a reduction in EG, JG and JEG for systolic pressure and diastolic only for JG and JEG. The GJ consumption to the practice of aerobic exercise provided reductions in the arterial pressure of hypertensive, in addition to stabilization of the diastolic pressure. Research limitations/implications Although the objective of the study was to compare the effect and value of intervention with controls, the study had no intervention in food consumption, which could have led to more significant results. There was a limitation in the control drink, leading the study not to be blind, which may have impaired the results. However, it is probably not a bias, as the groups were divided by residence area, and therefore, had no direct contact with the other groups. Another limitation was that the sample size was still small, which would lead to more reliable results. Finally, although the existing limitations cannot be disregarded, the results of this research are very promising, especially when the objective is the effect of GJ and aerobic exercise on blood pressure, with the possibility of implementing supplemental GJ and the inclusion or not of exercise to the hypertensive elderly. Originality/value The paper deals with the benefits of GJ consumption associated with aerobic physical exercise on the blood pressure of elderly hypertensive patients. Considering that GJ along with physical exercise was enough to reduce the blood pressure of hypertensive elderly, this may be a new model to be used to reduce and/or control blood pressure, and GJ and the exercise to be part of the daily life of the population.

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COUNIL, FRAN??OIS-PIERRE, ALAIN VARRAY, CHANTAL KARILA, MAURICE HAYOT, MICHEL VOISIN e CHRISTIAN PR??FAUT. "Wingate test performance in children with asthma: aerobic or anaerobic limitation?" Medicine &amp Science in Sports &amp Exercise 29, n. 4 (aprile 1997): 430–35. http://dx.doi.org/10.1097/00005768-199704000-00002.

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Rubalcaba, Juan G., Wilco C. E. P. Verberk, A. Jan Hendriks, Bart Saris e H. Arthur Woods. "Oxygen limitation may affect the temperature and size dependence of metabolism in aquatic ectotherms". Proceedings of the National Academy of Sciences 117, n. 50 (30 novembre 2020): 31963–68. http://dx.doi.org/10.1073/pnas.2003292117.

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Both oxygen and temperature are fundamental factors determining metabolic performance, fitness, ecological niches, and responses of many aquatic organisms to climate change. Despite the importance of physical and physiological constraints on oxygen supply affecting aerobic metabolism of aquatic ectotherms, ecological theories such as the metabolic theory of ecology have focused on the effects of temperature rather than oxygen. This gap currently impedes mechanistic models from accurately predicting metabolic rates (i.e., oxygen consumption rates) of aquatic organisms and restricts predictions to resting metabolism, which is less affected by oxygen limitation. Here, we expand on models of metabolic scaling by accounting for the role of oxygen availability and temperature on both resting and active metabolic rates. Our model predicts that oxygen limitation is more likely to constrain metabolism in larger, warmer, and active fish. Consequently, active metabolic rates are less responsive to temperature than are resting metabolic rates, and metabolism scales to body size with a smaller exponent whenever temperatures or activity levels are higher. Results from a metaanalysis of fish metabolic rates are consistent with our model predictions. The observed interactive effects of temperature, oxygen availability, and body size predict that global warming will limit the aerobic scope of aquatic ectotherms and may place a greater metabolic burden on larger individuals, impairing their physiological performance in the future. Our model reconciles the metabolic theory with empirical observations of oxygen limitation and provides a formal, quantitative framework for predicting both resting and active metabolic rate and hence aerobic scope of aquatic ectotherms.

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Lendraitiene, Egle, Laura Smilgiene, Daiva Petruseviciene e Raimondas Savickas. "Changes and Associations between Cervical Range of Motion, Pain, Temporomandibular Joint Range of Motion and Quality of Life in Individuals with Migraine Applying Physiotherapy: A Pilot Study". Medicina 57, n. 6 (17 giugno 2021): 630. http://dx.doi.org/10.3390/medicina57060630.

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Background and Objectives: The aim of this study was to assess the effects of physiotherapy with aerobic exercise together with temporomandibular joint range of motion exercises (supervised) and physiotherapy with aerobic exercise only (unsupervised), also to review the correlations between neck movements, pain, temporomandibular joint range of motion movements and quality of life in individuals with migraine. Methods: The flexion, extension and lateral flexion of the cervical spine were measured in degrees with a mechanical goniometer and pressure pain thresholds with algometer. Quality of life was assessed with the SF-36 questionnaire and temporomandibular joint range of motion with a centimeter. Results: The study showed statistically significant cervical flexion results in both groups (p < 0.05), masticatory muscle results and temporomandibular joint range of motion between the groups (p < 0.05). A correlation between left upper trapezius muscle pain and cervical lateral flexion was observed in the intervention group. Physical activity correlated with cervical extension, activity limitation due to physical ailments and general health. A correlation between temporomandibular joint and right-side masticatory muscles pain was found. A correlation between upper trapezius muscle pain and left- as well as right-side temporalis muscles were found in the control group. Strong correlations were found between pain and activity limitation due to physical ailments and emotional state. The temporomandibular joint range of motion strongly correlated with activity limitation due to physical ailments. Conclusions: Physiotherapy based on aerobic exercises together with temporomandibular joint exercises was more effective than physiotherapy based on aerobic exercise for decreasing pain, increasing pressure pain thresholds and cervical range of motion.

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Fong, Karen P., Ling Gao e Donald R. Demuth. "luxS and arcB Control Aerobic Growth of Actinobacillus actinomycetemcomitans under Iron Limitation". Infection and Immunity 71, n. 1 (gennaio 2003): 298–308. http://dx.doi.org/10.1128/iai.71.1.298-308.2003.

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ABSTRACT LuxS is responsible for the production of autoinducer 2 (AI-2), which functions in Vibrio harveyi as a quorum-sensing signal that controls the cell density-dependent expression of the lux operon. In nonluminescent organisms, the physiologic role of AI-2 is not clear. We report that inactivation of luxS in Actinobacillus actinomycetemcomitans JP2 results in reduced growth of the mutant, but not the wild-type organism, under aerobic, iron-limited conditions. Stunted cultures of the luxS mutant A. actinomycetemcomitans JP2-12 grew to high cell density when subcultured under iron-replete conditions. In addition, the mutant strain grew to high cell density under iron limitation after transformation with a plasmid containing a functional copy of luxS. Results of real-time PCR showed that A. actinomycetemcomitans JP2-12 exhibited significantly reduced expression of afuA (eightfold), fecBCDE (10-fold), and ftnAB (>50-fold), which encode a periplasmic ferric transport protein, a putative ferric citrate transporter, and ferritin, respectively. The expressions of putative receptors for transferrin, hemoglobin, and hemophore binding protein were also reduced at more modest levels (two- to threefold). In contrast, expressions of sidD and frpB (encoding putative siderophore receptors) were increased 10- and 3-fold, respectively, in the luxS mutant. To better understand the mechanism of the AI-2 response, the A. actinomycetemcomitans genome was searched for homologs of the V. harveyi signal transduction proteins, LuxP, LuxQ, LuxU, and LuxO. Interestingly, ArcB was found to be most similar to LuxQ sensor/kinase. To determine whether arcB plays a role in the response of A. actinomycetemcomitans to AI-2, an arcB-deficient mutant was constructed. The isogenic arcB mutant grew poorly under anaerobic conditions but grew normally under aerobic iron-replete conditions. However, the arcB mutant failed to grow aerobically under iron limitation, and reverse transcriptase PCR showed that inactivation of arcB resulted in decreased expression of afuA and ftnAB. Thus, isogenic luxS and arcB mutants of A. actinomycetemcomitans exhibit similar phenotypes when cultured aerobically under iron limitation, and both mutants exhibit reduced expression of a common set of genes involved in the transport and storage of iron. These results suggest that LuxS and ArcB may act in concert to control the adaptation of A. actinomycetemcomitans to iron-limiting conditions and its growth under such conditions.

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Ende, Frank P., Anniet M. Laverman e Hans Gemerden. "Coexistence of aerobic chemotrophic and anaerobic phototrophic sulfur bacteria under oxygen limitation". FEMS Microbiology Ecology 19, n. 3 (marzo 1996): 141–51. http://dx.doi.org/10.1111/j.1574-6941.1996.tb00207.x.

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VANDENENDE, F., A. LAVERMAN e H. VANGEMERDEN. "Coexistence of aerobic chemotrophic and anaerobic phototrophic sulfur bacteria under oxygen limitation". FEMS Microbiology Ecology 19, n. 3 (marzo 1996): 141–51. http://dx.doi.org/10.1016/0168-6496(95)00082-8.

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Punrattanasin, W., A. A. Randall e C. W. Randall. "Aerobic production of activated sludge polyhydroxyalkanoates from nutrient deficient wastewaters". Water Science and Technology 54, n. 8 (1 ottobre 2006): 1–8. http://dx.doi.org/10.2166/wst.2006.757.

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It was found that aerobic strategies combined with multiple nutrient limitations produced greater quantities of polyhydroxyalkanoates (PHAs) than strategies relying on oxygen limitation (either micro-aerophilic or anaerobic/aerobic). This was true both for a synthetic wastewater composed of acetic and propionic acid, and also for a nutrient deficient industrial wastewater. PHA/substrate yields were shown to be comparable to axenic systems for many operating strategies analyzed, and it was found that PHA composition could be affected by process operational conditions. The molecular weight and melting point of the PHA produced were found to be in a desirable range with respect to material properties, which have not been well studied in the previous literature for mixed cultures (Salehizadeh and Van Loodsrecht, 2004). The effects of process staging, multiple treatment cycles, and inocula source were also addressed.

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Hochachka, P. W., J. C. Nener, J. Hoar, R. K. Saurez e S. C. Hand. "Disconnecting metabolism from adenylate control during extreme oxygen limitation". Canadian Journal of Zoology 71, n. 6 (1 giugno 1993): 1267–70. http://dx.doi.org/10.1139/z93-173.

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When deprived of oxygen, the desert locust (Schistocerca gregaria) enters a state of apparent dormancy, from which it can recover when oxygen is again made available. Calorimetric measurements show that with an atmosphere of 100% nitrogen, energy flow in locusts reaches a new steady-state rate of heat dissipation of only 6 – 7% of aerobic values. Metabolite analysis shows large decreases in concentrations of arginine phosphate and adenosine triphosphate during anoxia, while adenosine monophosphate, lactate, α-glycerophosphate, and Pi accumulate to significantly elevated levels during anoxia. Time-course studies on whole animals and flight muscle paradoxically show declining metabolic rates when changes in metabolite (especially adenylate) concentration would normally be expected to activate metabolism.

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Hopkins, S. R., D. C. McKenzie, R. B. Schoene, R. W. Glenny e H. T. Robertson. "Pulmonary gas exchange during exercise in athletes. I. Ventilation-perfusion mismatch and diffusion limitation". Journal of Applied Physiology 77, n. 2 (1 agosto 1994): 912–17. http://dx.doi.org/10.1152/jappl.1994.77.2.912.

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To investigate pulmonary gas exchange during exercise in athletes, 10 high aerobic capacity athletes (maximal aerobic capacity = 5.15 +/- 0.52 l/min) underwent testing on a cycle ergometer at rest, 150 W, 300 W, and maximal exercise (372 +/- 22 W) while trace amounts of six inert gases were infused intravenously. Arterial blood samples, mixed expired gas samples, and metabolic data were obtained. Indexes of ventilation-perfusion (VA/Q) mismatch were calculated by the multiple inert gas elimination technique. The alveolar-arterial difference for O2 (AaDO2) was predicted from the inert gas model on the basis of the calculated VA/Q mismatch. VA/Q heterogeneity increased significantly with exercise and was predicted to increase the AaDO2 by > 17 Torr during heavy and maximal exercise. The observed AaDO2 increased significantly more than that predicted by the inert gas technique during maximal exercise (10 +/- 10 Torr). These data suggest that this population develops diffusion limitation during maximal exercise, but VA/Q mismatch is the most important contributor (> 60%) to the wide AaDO2 observed.

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Taboada, Hermenegildo, Sergio EncarnaciÃ³n, MarÃa del Carmen Vargas, Yolanda Mora, Juan Miranda-RÃos, Mario SoberÃ³n e Jaime Mora. "Thiamine limitation determines the transition from aerobic to fermentative-like metabolism inRhizobium etliCE3". FEMS Microbiology Letters 279, n. 1 (febbraio 2008): 48–55. http://dx.doi.org/10.1111/j.1574-6968.2007.01006.x.

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Smith, Daniel P. "Oxygen flux limitation in aerobic fixed-film biotreatment of a hazardous landfill leachate". Journal of Hazardous Materials 44, n. 1 (novembre 1995): 77–91. http://dx.doi.org/10.1016/0304-3894(95)00050-5.

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Stickland, Michael K., Scott J. Butcher, Darcy D. Marciniuk e Mohit Bhutani. "Assessing Exercise Limitation Using Cardiopulmonary Exercise Testing". Pulmonary Medicine 2012 (2012): 1–13. http://dx.doi.org/10.1155/2012/824091.

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The cardiopulmonary exercise test (CPET) is an important physiological investigation that can aid clinicians in their evaluation of exercise intolerance and dyspnea. Maximal oxygen consumption (V˙O2max) is the gold-standard measure of aerobic fitness and is determined by the variables that define oxygen delivery in the Fick equation (V˙O2= cardiac output × arterial-venous O2content difference). In healthy subjects, of the variables involved in oxygen delivery, it is the limitations of the cardiovascular system that are most responsible for limiting exercise, as ventilation and gas exchange are sufficient to maintain arterial O2content up to peak exercise. Patients with lung disease can develop a pulmonary limitation to exercise which can contribute to exercise intolerance and dyspnea. In these patients, ventilation may be insufficient for metabolic demand, as demonstrated by an inadequate breathing reserve, expiratory flow limitation, dynamic hyperinflation, and/or retention of arterial CO2. Lung disease patients can also develop gas exchange impairments with exercise as demonstrated by an increased alveolar-to-arterial O2pressure difference. CPET testing data, when combined with other clinical/investigation studies, can provide the clinician with an objective method to evaluate cardiopulmonary physiology and determination of exercise intolerance.

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Valdez, Josie A. "Mapping Suitable Areas of Central Luzon, Philippines for Aerobic Rice Production Using GIS-Based Land Suitability Analysis". Philippine Journal of Agricultural Economics 2, n. 1 (22 febbraio 2018): 107–31. http://dx.doi.org/10.7719/pjae.v2i1.549.

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Aerobic rice technology is a production system which involved drought-tolerant rice varieties grown in non-flooded and non-puddled soil in water-scarce areas with appropriate cultural management practices aiming at yield level up to 6.0 tons ha. The study presented suitability maps and spatial data to aerobic rice under different production environments of the Central Luzon Region, Philippines. Simple limitation approach (SLA) was used to derive the overall suitability of aerobic rice production in these areas. Spatial datasets gathered from official sources were likewise used. Of the seven provinces, Nueva Ecija had the biggest potential area of 547,735.80 hectares with 11.49% marked as highly suitable to aerobic rice technology, followed by Bulacan which had a potential area of 255,022.52 hectares with 6.15% marked as highly suitable. Pampanga, Tarlac, Zambales, Aurora and Bataan followed with 6.15 %, 5.88 %, 2.65 %, 1.59 %t and 1.56%, respectively, of their corresponding potential areas suitable for aerobic rice production. The total land area in Central Luzon which was found to be highly suitable for aerobic rice production was 126,959.91 hectares. On the assumption that ART could give an average yield of 4.5 tons per hectare, Central Luzon can supply an additional 571,319.59 metric tons of aerobic rice annually.

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Duke, Joseph W., Amy M. Zidron, Igor M. Gladstone e Andrew T. Lovering. "Alleviating mechanical constraints to ventilation with heliox improves exercise endurance in adult survivors of very preterm birth". Thorax 74, n. 3 (14 settembre 2018): 302–4. http://dx.doi.org/10.1136/thoraxjnl-2018-212346.

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Adult survivors of very preterm birth (PRET) have significantly lower aerobic exercise capacities than their counterparts born at term (CONT), but the underlying cause is unknown. To test whether expiratory flow limitation (EFL) during exercise negatively affects exercise endurance in PRET, we had PRET and CONT exercise to exhaustion breathing air and again breathing heliox. In PRET, EFL decreased and time-to-exhaustion increased significantly while breathing heliox. Heliox had a minimal effect on EFL and had no effect on time-to-exhaustion in CONT. We conclude that aerobic exercise endurance in PRET is limited, in part, by mechanical ventilatory constraints, specifically EFL.

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Vijayaraghavareddy, Preethi, Yin Xinyou, Paul C. Struik, Udayakumar Makarla e Sheshshayee Sreeman. "Responses of Lowland, Upland and Aerobic Rice Genotypes to Water Limitation During Different Phases". Rice Science 27, n. 4 (luglio 2020): 345–54. http://dx.doi.org/10.1016/j.rsci.2020.05.009.

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29

Sneidere, Kristine, Jelena Harlamova, Zane Ulmane, Voldemars Arnis, Andra Vanaga e Ainars Stepens. "RELATIONSHIP BETWEEN INVOLVEMENT IN LONG- TERM REGULAR PHYSICAL ACTIVITY AND MEMORY: PRELIMINARY RESULTS". Baltic Journal of Sport and Health Sciences 4, n. 107 (2017): 23–27. http://dx.doi.org/10.33607/bjshs.v4i107.36.

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Abstract (sommario):

Background. Ageing of the Western Society has become both – economic and social concern. Ageing has both – biological and psychological consequences, and, with changes in the brain due to ageing (e.g. decline in the brain volume in frontal, parietal and temporal areas, as well as hippocampus (Colcombe et al., 2003; Erickson, Voss, Shaurya, Basak, & Szabo, 2011)), there are changes in cognitive functioning. For the past years, research has indicated a relationship between aerobic activity interventions and increase in episodic memory (Ruscheweyh et al., 2011), face recognition associative memory (Hayes et al., 2015) and working memory (Erickson et al., 2011). Methods. The aim of the study was to examine the relationship between involvement in aerobic physical activities and memory; thus 43 seniors aged from 65 to 85 (M = 71.86, SD = 5.09, 23% male) were included in the study. Based on their physical activity experience, participants were divided into three groups – seniors with long- term aerobic physical activity experience (n = 16), seniors that have recently taken up aerobic physical activities (n = 19) and seniors not involved in physical activities (n = 8). Results. The preliminary data indicated relationship between long-term involvement in physical activities and working memory, as well as negative relationship between sedentary lifestyle and overall cognitive abilities. Conclusions. As this is still a work in progress, one of the limitations being the small sample, these results can be considered only as a tendency. Another limitation is the unequal gender distribution. This study was funded by the Latvian National Research Programme BIOMEDICINE 2014–2017.

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30

Gibson, Carmela M., T. Conn Mallett, Al Claiborne e Michael G. Caparon. "Contribution of NADH Oxidase to Aerobic Metabolism of Streptococcus pyogenes". Journal of Bacteriology 182, n. 2 (15 gennaio 2000): 448–55. http://dx.doi.org/10.1128/jb.182.2.448-455.2000.

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Abstract (sommario):

ABSTRACT An understanding of how the heme-deficient gram-positive bacteriumStreptococcus pyogenes establishes infections in O2-rich environments requires careful analysis of the gene products important in aerobic metabolism. NADH oxidase (NOXase) is a unique flavoprotein of S. pyogenes and other lactic acid bacteria which directly catalyzes the four-electron reduction of O2 to H2O. To elucidate a putative role for this enzyme in aerobic metabolism, NOXase-deficient mutants were constructed by insertional inactivation of the gene that encodes NOXase. Characterization of the resulting mutants revealed that growth in rich medium under low-O2 conditions was indistinguishable from that of the wild type. However, the mutants were unable to grow under high-O2 conditions and demonstrated enhanced sensitivity to the superoxide-generating agent paraquat. Mutants cultured in liquid medium under conditions of carbohydrate limitation and high O2 tension were characterized by an extended lag phase, a reduction in growth, and a greater accumulation of H2O2 in the growth medium compared to the wild-type strain. All of these mutant phenotypes could be overcome by the addition of glucose. Either the addition of catalase to the culture medium of the mutants or the introduction of a heterologous NADH peroxidase into the mutants eliminated the accumulation of H2O2 and rescued the growth defect of the mutants under high-O2 conditions in carbohydrate-limited liquid medium. Taken together, these data show that NOXase is important for aerobic metabolism and essential in environments high in O2 with carbohydrate limitation.

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31

Tokutomi, T., T. Kiyokawa, C. Shibayama, H. Harada e A. Ohashi. "Effect of inorganic carbon on nitrite accumulation in an aerobic granule reactor". Water Science and Technology 53, n. 12 (1 giugno 2006): 285–94. http://dx.doi.org/10.2166/wst.2006.431.

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Abstract (sommario):

Pilot scale experiments were performed to evaluate the potential of nitrite type nitrification process with an airlift reactor and granular biomass. Initially, oxygen limitation was used as the main control parameter for accumulating nitrite in the effluent. After 30 d operation, the maximum nitrite conversion rate reached 2.5 kgNO2-N m−3 d−1, average diameter of the granule was 0.7 mm. Nitrite type reaction continued over 100 d, but nitrate formation increased after 150 d of operation. Once nitrate formation increased, oxygen limitation could not eliminate nitrite oxidising bacteria from granule. To overcome nitrate formation, laboratory scale batch experiments were conducted and it revealed a high concentration of inorganic carbon which had a significant effect on nitrite accumulation. Following this new concept, inorganic carbon was fed to the pilot scale reactor by changing pH adjustment reagent from NaOH to Na2CO3 and nitrite accumulation was recovered successfully without changing DO concentration. These results show that a high concentration of inorganic carbon is one of the control parameters for accumulating nitrite in biofilm nitrification system.

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32

Nakano, Michiko M., e Yi Zhu. "Involvement of ResE Phosphatase Activity in Down-Regulation of ResD-Controlled Genes in Bacillus subtilis during Aerobic Growth". Journal of Bacteriology 183, n. 6 (15 marzo 2001): 1938–44. http://dx.doi.org/10.1128/jb.183.6.1938-1944.2001.

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Abstract (sommario):

ABSTRACT The ResD-ResE signal transduction system is required for aerobic and anaerobic respiration in Bacillus subtilis. The histidine sensor kinase ResE, by functioning as a kinase and a phosphatase for the cognate response regulator ResD, controls the level of phosphorylated ResD. A high level of phosphorylated ResD is postulated to cause a dramatic increase in transcription of ResDE-controlled genes under anaerobic conditions. A mutant ResE, which retains autophosphorylation and ResD phosphorylation activities but is defective in ResD dephosphorylation, allowed partially derepressed aerobic expression of the ResDE-controlled genes. The result indicates that phosphatase activity of ResE is regulated by oxygen availability and anaerobic induction of the ResDE regulon is partly due to a reduction of the ResE phosphatase activity during anaerobiosis. That elimination of phosphatase activity does not result in complete aerobic derepression suggests that the ResE kinase activity is also subject to control in response to oxygen limitation.

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33

Mota, Susana, Pere Casan, Franchek Drobnic, Jordi Giner, Olga Ruiz, Joaquín Sanchis e Joseph Milic-Emili. "Expiratory flow limitation during exercise in competition cyclists". Journal of Applied Physiology 86, n. 2 (1 febbraio 1999): 611–16. http://dx.doi.org/10.1152/jappl.1999.86.2.611.

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Abstract (sommario):

In some trained athletes, maximal exercise ventilation is believed to be constrained by expiratory flow limitation (FL). Using the negative expiratory pressure method, we assessed whether FL was reached during a progressive maximal exercise test in 10 male competition cyclists. The cyclists reached an average maximal O2 consumption of 72 ml ⋅ kg−1 ⋅ min−1(range: 67–82 ml ⋅ kg−1 ⋅ min−1) and ventilation of 147 l/min (range: 122–180 l/min) (88% of preexercise maximal voluntary ventilation in 15 s). In nine subjects, FL was absent at all levels of exercise (i.e., expiratory flow increased with negative expiratory pressure over the entire tidal volume range). One subject, the oldest in the group, exhibited FL during peak exercise. The group end-expiratory lung volume (EELV) decreased during light-to-moderate exercise by 13% (range: 5–33%) of forced vital capacity but increased as maximal exercise was approached. EELV at peak exercise and at rest were not significantly different. The end-inspiratory lung volume increased progressively throughout the exercise test. The conclusions reached are as follows: 1) most well-trained young cyclists do not reach FL even during maximal exercise, and, hence, mechanical ventilatory constraint does not limit their aerobic exercise capacity, and 2) in absence of FL, EELV decreases initially but increases during heavy exercise.

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34

Frederich, Markus, e Hans O. Pörtner. "Oxygen limitation of thermal tolerance defined by cardiac and ventilatory performance in spider crab, Maja squinado". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 279, n. 5 (1 novembre 2000): R1531—R1538. http://dx.doi.org/10.1152/ajpregu.2000.279.5.r1531.

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Abstract (sommario):

Geographic distribution limits of ectothermal animals appear to be correlated with thermal tolerance thresholds previously identified from the onset of anaerobic metabolism. Transition to these critical temperatures was investigated in the spider crab ( Maja squinado) with the goal of identifying the physiological processes limiting thermal tolerance. Heart and ventilation rates as well as Po 2 in the hemolymph were recorded on-line during progressive temperature change between 12 and 0°C (1°C/h) and between 12 and 40°C (2°C/h). Lactate and succinate were measured in tissues and hemolymph after intermediate or final temperatures were reached. High levels of hemolymph oxygenation suggest that an optimum range of aerobic performance exists between 8 and 17°C. Thermal limitation may already set in at the transition from optimum to pejus (pejus = turning worse, progressively deleterious) range, characterized by the onset of a decrease in arterial Po 2 due to reduced ventilatory and cardiac performance. Hemolymph Po 2 values fell progressively toward both low and high temperature extremes until critical temperatures were reached at ∼1 and 30°C, as indicated by low Po 2 and the onset of anaerobic energy production by mitochondria. In conclusion, the limited capacity of ventilation and circulation at extreme temperatures causes insufficient O2 supply, thereby limiting aerobic scope and, finally, thermal tolerance.

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35

Sato-Takabe, Yuki, Koji Hamasaki e Koji Suzuki. "Photosynthetic Competence of the Marine Aerobic Anoxygenic Phototrophic Bacterium Roseobacter sp. under Organic Substrate Limitation". Microbes and Environments 29, n. 1 (2014): 100–103. http://dx.doi.org/10.1264/jsme2.me13130.

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36

Campillo-Gimenez, Laure, Michael Li, Elsa Molina e Peter B. Ernst. "Adenosine receptor signaling regulates effector T cell activation through the limitation of aerobic glucose metabolism." Journal of Immunology 208, n. 1_Supplement (1 maggio 2022): 165.01. http://dx.doi.org/10.4049/jimmunol.208.supp.165.01.

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Abstract (sommario):

Abstract Background In a mouse model of colitis, we previously reported the protective role of the adenosine axis on effector T (Teff) cell responses and disease progression. Inflammatory reactions are paired with cell metabolic reprogramming from oxidative phosphorylation (OXPHOS) to aerobic glycolysis which is also a hallmark of T cell activation. Thus, we sought to evaluate the role of the adenosine 2A receptor (A2AR) signaling in the regulation of T cell metabolism. Methods Teff cells were reactivated in the presence or absence of A2AR agonists. Gene expression of mTOR, HIF-1α and cMyc (transcriptional factors of glycolysis-related genes) were quantified by qPCR. T cell metabolic phenotype was evaluated by transcriptomic profiling (Nanostring nCounter® Metabolic Pathway Panel), as well as real-time extracellular flux analysis, glucose uptake, and ATP production assays. Results mTOR, HIF-1α and cMyc gene expression increased as soon as 2hr post stimulation. At this time point, transcriptomic analysis revealed an A2AR agonist-induced downregulation of pathways related to T cell activation (i.e. mTOR, MAPK, PI3K, NFκB and cMyc pathways) and energy metabolism (i.e glycolysis, autophagy, fatty acid synthesis) whereas oxidative metabolism pathways (OXPHOS, fatty acid oxidation, glutamine metabolism) were upregulated (Pathway Score q-value <0.05). Functional assays showed a decreased de novo glucose uptake and glycolysis rate after A2AR agonist treatment while OXPHOS capacity and ATP production were not modulated. Conclusion A2AR signaling provokes a rewiring of the activated T cell metabolism towards an oxidative state making adenosine a potential T cell metabolic regulator that can be exploited in the treatment of IBD. Supported by NIH R01AI079145

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37

Notley-McRobb, Lucinda, Rachel Pinto, Shona Seeto e Thomas Ferenci. "Regulation of mutY and Nature of Mutator Mutations in Escherichia coli Populations under Nutrient Limitation". Journal of Bacteriology 184, n. 3 (1 febbraio 2002): 739–45. http://dx.doi.org/10.1128/jb.184.3.739-745.2002.

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Abstract (sommario):

ABSTRACT Previous analysis of aerobic, glucose-limited continuous cultures of Escherichia coli revealed that G:C-to-T:A (G:C→T:A) transversions were the most commonly occurring type of spontaneous mutation. One possible explanation for the preponderance of these mutations was that nutrient limitation repressed MutY-dependent DNA repair, resulting in increased proportions of G:C→T:A transversions. The regulation of the mutY-dependent DNA repair system was therefore studied with a transcriptional mutY-lacZ fusion recombined into the chromosome. Expression from the mutY promoter was fourfold higher under aerobic conditions than under anaerobic conditions. But mutY expression was higher in glucose- or ammonia-limited chemostats than in nutrient-excess batch culture, so mutY was not downregulated by nutrient limitation. An alternative explanation for the frequency of G:C→T:A transversions was the common appearance of mutY mutator mutations in the chemostat populations. Of 11 chemostat populations screened in detail, six contained mutators, and the mutator mutation in four cultures was located in the region of mutY at 66 min on the chromosome. The spectrum of mutations and rate of mutation in these isolates were fully consistent with a mutY-deficiency in each strain. Based on PCR analysis of the region within and around mutY, isolates from three individual populations contained deletions extending at least 2 kb upstream of mutY and more than 5 kb downstream. In the fourth population, the deletion was even longer, extending at least 5 kb upstream and 5 kb downstream of mutY. The isolation of mutY mutator strains from four independent populations with extensive chromosomal rearrangements suggests that mutY inactivation by deletion is a means of increasing mutation rates under nutrient limitation and explains the observed frequency of G:C→T:A mutations in glucose-limited chemostats.

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38

Szortyka, Michele Fonseca, Viviane Batista Cristiano e Paulo Belmonte-de-Abreu. "Aerobic and Postural Strength Exercise Benefits in People with Schizophrenia". International Journal of Environmental Research and Public Health 20, n. 4 (15 febbraio 2023): 3421. http://dx.doi.org/10.3390/ijerph20043421.

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Abstract (sommario):

Background: This study aimed to evaluate the effect of two different types of physical intervention on sedentary behavior and clinical changes in people with schizophrenia. Method: This is a clinical trial including people with schizophrenia in regular outpatient care who realized a 3-month exercise protocol and were separated into two groups: aerobic physical intervention (API) and postural physical intervention (PPI). All participants performed an assessment of (a) functional capacity through a 6 min walk test (6MWT), (b) flexibility using Well’s bench, (c) disease severity using the Brief Psychiatric Rating Scale (BPRS), (d) quality of life using the SF-36 Questionnaire and (e) physical activity using the Simple Physical Activity Questionnaire (SIMPAQ). Results: Thirty-eight patients with schizophrenia completed the intervention (24 patients in API and 14 patients in PPI). Regarding sedentary behavior, there was an improvement in the API group in the time exercising and in the PPI group concerning time in bed, time walking and exercising. Regarding quality of life, there was an improvement in the API group (functional capacity) and in the PPI group, there was an improvement in physical limitation, pain and emotional limitations. In the API group, there was an improvement in BMI (body mass index), diastolic blood pressure and systolic blood pressure. Functional capacity was improved only in the PPI group. There was no change in flexibility and disease severity. Conclusions: The study demonstrated a change response in the physical and mental aspects in people with schizophrenia after a change in sedentary behavior.

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Yadav, Amit, Swati Gupta, Paula Istvan e Zeev Ronen. "Effects of Perchlorate and Other Groundwater Inorganic Co-Contaminants on Aerobic RDX Degradation". Microorganisms 10, n. 3 (20 marzo 2022): 663. http://dx.doi.org/10.3390/microorganisms10030663.

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Abstract (sommario):

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) pollution is accompanied by other co-contaminants, such as perchlorate and chlorates, which can retard biodegradation. The effects of perchlorate and chlorate on aerobic RDX degradation remain unclear. We hypothesized that they have a negative or no impact on aerobic RDX-degrading bacteria. We used three aerobic RDX-degrading strains—Rhodococcus strains YH1 and T7 and Gordonia YY1—to examine this hypothesis. The strains were exposed to perchlorate, chlorate, and nitrate as single components or in a mixture. Their growth, degradation activity, and gene expression were monitored. Strain-specific responses to the co-contaminants were observed: enhanced growth of strain YH1 and inhibition of strain T7. Vmax and Km of cytochrome P450 (XplA) in the presence of the co-contaminants were not significantly different from the control, suggesting no direct influence on cytochrome P450. Surprisingly, xplA expression increased fourfold in cultures pre-grown on RDX and, after washing, transferred to a medium containing only perchlorate. This culture did not grow, but xplA was translated and active, albeit at lower levels than in the control. We explained this observation as being due to nitrogen limitation in the culture and not due to perchlorate induction. Our results suggest that the aerobic strain YH1 is effective for aerobic remediation of RDX in groundwater.

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40

Chappell, M. A., C. Bech e W. A. Buttemer. "The relationship of central and peripheral organ masses to aerobic performance variation in house sparrows". Journal of Experimental Biology 202, n. 17 (1 settembre 1999): 2269–79. http://dx.doi.org/10.1242/jeb.202.17.2269.

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Abstract (sommario):

We evaluated the relationship between organ mass and the limits to aerobic metabolism in house sparrows Passer domesticus. The results were used to test three models of performance limitation (the central limitation, peripheral limitation and symmorphosis concepts). Basal metabolic rate (BMR) was determined during the rest phase. The maximum rate of oxygen consumption during exercise (v_dot (O2max)) was measured in an enclosed wheel that allowed limited hovering flight. Neither BMR nor v_dot (O2max) was affected by gender, but adults had significantly higher v_dot (O2max) and lower BMR than juveniles. The masses of most central organs (gut, gizzard, liver, heart, kidney and reproductive organs) differed significantly between ages. There were no gender differences in organ mass among juveniles, but liver mass differed between male and female adults. In the pooled data, BMR was positively correlated with the mass of three central organs (gut, liver and kidney) and with one peripheral effector (breast muscle); together, these explained more than half the variance in BMR (r(2)=0.57). In adults, BMR was positively correlated with the mass of reproductive tissue. The masses of one peripheral effector (breast muscle) and one central organ (the heart) were positively correlated with v_dot (O2max) (r(2)=0.17 for the pooled data set). These results are consistent with a symmorphosis model of aerobic capacity. We found a significant positive relationship between BMR and v_dot (O2max) in juveniles, but not in adults. Taken together, our data indicate that house sparrows can achieve elevated v_dot (O2max) without paying a ‘penalty’ (fitness trade-off) in the form of an increased BMR.

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41

Filali, Ahlem, Yolaine Bessiere e Mathieu Sperandio. "Effects of oxygen concentration on the nitrifying activity of an aerobic hybrid granular sludge reactor". Water Science and Technology 65, n. 2 (1 gennaio 2012): 289–95. http://dx.doi.org/10.2166/wst.2012.795.

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Abstract (sommario):

The aim of the work was to quantify the influence of the simultaneous presence of flocs and granules in the nitrifying activity in a sequencing batch airlift reactor (SBAR). The nitrification rate and oxygen limitation of flocs, granules and hybrid sludge was investigated using respirometric assays at different dissolved oxygen concentrations. The spatial distribution of Ammonium Oxidizing Bacteria (AOB) and Nitrite Oxidizing Bacteria (NOB) was investigated using fluorescence in situ hybridization (FISH). Results showed that the nitrification rate was much less sensitive to oxygen limitation in systems containing a fraction of flocs than in pure granular sludge. Ammonium Oxidizing Bacteria (AOB) were found to be distributed in similar quantities in flocs and granules whereas the Nitrite Oxidizing Bacteria (NOB) were located preferentially in granules. This study showed that the presence of flocs with granules could increase the robustness of the process to transitory reductions of aeration.

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42

Kijowski, Jacek, Celina Marciszewska, Renata Cegielska-Radziejewska e Anna Popiół. "Effect of Lysozyme Treatment on Quality and Bacterial Contamination of Chilled Chicken Legs". Bulletin of the Veterinary Institute in Pulawy 57, n. 1 (1 marzo 2013): 79–84. http://dx.doi.org/10.2478/bvip-2013-0015.

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Abstract (sommario):

AbstractThe effect of spraying lysozyme solutions of varying activity on microbiological stability and organoleptic features of chicken legs with skin was investigated. Lysozyme was applied at concentrations ranging from 3,000 to 48,000 U/mL. The effect of storage time at 4oC on the total aerobic bacterial count, coli titre, occurrence of enterococci, anaerobic spore forming bacilli, and pathogenic staphylococci was analysed along with the examination of sensory quality attributes. The investigations showed that the addition of lysozyme resulted in a considerable inhibition of growth of the initial aerobic bacterial counts and a limitation of disadvantageous organoleptic changes during cold storage of the legs. The lysozyme solution with the activity of 48,000 U/mL caused a 20-fold reduction in the initial aerobic bacterial count. Sensory examination showed that samples subjected to the action of lysozyme and stored for 120 h under cold storage conditions did not differ qualitatively from fresh legs. The obtained results revealed that lysozyme might be an effective agent extending shelf-life of portioned poultry meat.

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Jiang, Qing-Qiao, e Lars R. Bakken. "Nitrous Oxide Production and Methane Oxidation by Different Ammonia-Oxidizing Bacteria". Applied and Environmental Microbiology 65, n. 6 (1 giugno 1999): 2679–84. http://dx.doi.org/10.1128/aem.65.6.2679-2684.1999.

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Abstract (sommario):

ABSTRACT Ammonia-oxidizing bacteria (AOB) are thought to contribute significantly to N2O production and methane oxidation in soils. Most of our knowledge derives from experiments withNitrosomonas europaea, which appears to be of minor importance in most soils compared to Nitrosospira spp. We have conducted a comparative study of levels of aerobic N2O production in six phylogenetically different Nitrosospirastrains newly isolated from soils and in two N. europaeaand Nitrosospira multiformis type strains. The fraction of oxidized ammonium released as N2O during aerobic growth was remarkably constant (0.07 to 0.1%) for all theNitrosospira strains, irrespective of the substrate supply (urea versus ammonium), the pH, or substrate limitation. N. europaea and Nitrosospira multiformis released similar fractions of N2O when they were supplied with ample amounts of substrates, but the fractions rose sharply (to 1 to 5%) when they were restricted by a low pH or substrate limitation. Phosphate buffer (versus HEPES) doubled the N2O release for all types of AOB. No detectable oxidation of atmospheric methane was detected. Calculations based on detection limits as well as data in the literature on CH4 oxidation by AOB bacteria prove that none of the tested strains contribute significantly to the oxidation of atmospheric CH4 in soils.

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44

Ensz, Andrew P., Charles W. Knapp e David W. Graham. "Influence of Autochthonous Dissolved Organic Carbon and Nutrient Limitation on Alachlor Biotransformation in Aerobic Aquatic Systems". Environmental Science & Technology 37, n. 18 (settembre 2003): 4157–62. http://dx.doi.org/10.1021/es0303790.

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45

Houweling, Dwight, Yves Comeau, Imre Takács e Peter Dold. "Uncertainty and variability in enhanced biological phosphorus removal (EBPR) stoichiometry: consequences for process modelling and optimization". Water Science and Technology 61, n. 7 (1 aprile 2010): 1793–800. http://dx.doi.org/10.2166/wst.2010.975.

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Abstract (sommario):

The overall potential for enhanced biological phosphorus removal (EBPR) in the activated sludge process is constrained by the availability of volatile fatty acids (VFAs). The efficiency with which polyphosphate accumulating organisms (PAOs) use these VFAs for P-removal, however, is determined by the stoichiometric ratios governing their anaerobic and aerobic metabolism. While changes in anaerobic stoichiometry due to environmental conditions do affect EBPR performance to a certain degree, model-based analyses indicate that variability in aerobic stoichiometry has the greatest impact. Long-term deterioration in EBPR performance in an experimental SBR system undergoing P-limitation can be predicted as the consequence of competition between PAOs and GAOs. However, the observed rapid decrease in P-release after the change in feed composition is not consistent with a gradual shift in population.

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46

Redding, Emma, e Matthew Wyon. "Strengths and Vífeaknesses of Current Methods for Evaluating the Aerobic Power of Dancers". Journal of Dance Medicine & Science 7, n. 1 (marzo 2003): 10–16. http://dx.doi.org/10.1177/1089313x0300700102.

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Abstract (sommario):

The methods of measuring aerobic power in dance is reviewed. The underlying metabolic pathways used during dance class and performance are examined and, in conclusion, dance has been classified as an intermittent form of exercise. The relevancy of measuring maximal oxygen uptake (VO2max) in relation to intermit-tent exercise is discussed with regard to other sports. Previous dance VO2max data is examined in relationship to other exercise forms and it is shown to be comparable to results in other non-endurance sports. The limitations of graded exercise tests with regards to extrapolating oxygen data from heart rates during dance has been highlighted as a flaw in a number of previous research studies and a limitation to be aware of in future re-search. Due to the infancy of dance science, the availability of valid and reliable laboratory and field tests are limited and, therefore, until further research is done, there needs to be a reliance on tests de-veloped in the health and sport environ-ments. Such tests should be graded, either in speed or gradient, with stages of at least 3 minutes and be weight-bearing. Even though no research to date has shown that dancers with improved VO2max perform better, the review suggests that both the aerobic and anaerobic systems need to be stressed to a greater extent than seen presently within dance class.

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47

Finke, E., H. O. Pörtner, P. G. Lee e D. M. Webber. "Squid (Lolliguncula brevis) life in shallow waters: oxygen limitation of metabolism and swimming performance." Journal of Experimental Biology 199, n. 4 (1 aprile 1996): 911–21. http://dx.doi.org/10.1242/jeb.199.4.911.

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Abstract (sommario):

Squid (Lolliguncula brevis) were exercised in a tunnel respirometer during a stepwise increase in water velocity in order to evaluate the anaerobic threshold, i.e. the critical swimming speed above which anaerobic metabolism contributes to energy production. The average anaerobic threshold was found at speeds of 1.5-2 mantle lengths s-1. Above this velocity, alpha-glycerophosphate, succinate and octopine started to accumulate in the mantle tissue. ATP levels fell and phospho-L-arginine was progressively depleted, while the levels of glucose 6-phosphate and inorganic phosphate rose. The finding of a simultaneous onset of anaerobic metabolism in the cytosol and the mitochondria indicates that a limited oxygen supply to the mitochondria elicits anaerobic energy production. This finding is opposite to the situation found in many other vertebrate and invertebrate species, in which energy requirements in excess of aerobic energy production are covered by anaerobic metabolism, with mitochondria remaining aerobic. In L. brevis, swimming at higher speeds is associated with a small factorial increase in metabolic rate based on a high resting rate of oxygen consumption. Pressure recordings in the mantle cavity support this finding, indicating a high basal level of spontaneous activity at rest and a small rise in mean pressure at higher swimming velocity. Bursts of higher pressures from the jet support elevated swimming speeds and may explain the early transition to anaerobic energy production which occurs when pressure amplitudes exceed 1.2-1.5 kPa or when mean pressure rises above 0.22-0.25 kPa. The finding of mitochondrial hypoxia at a low critical speed in these squid is interpreted to be related to their life in shallow coastal and bay waters, which limits the necessity to maintain high swimming velocities. At increased swimming velocities, the animals oscillate between periods of high and low muscular activity. This behaviour is interpreted to reduce transport cost and to permit a longer-term net use of anaerobic resources when speed exceeds the critical value or when the squid dive into hypoxic waters. The simultaneous onset of anaerobic metabolism in the cytosol and the mitochondria emphasizes that squid generally make maximal use of available oxygen under resting conditions, when their energy requirements are the highest among marine invertebrates.

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48

Shephard, Roy J. "Research Including Persons with Disabilities: Practical Issues and Contributions to Knowledge of Exercise Physiology". Adapted Physical Activity Quarterly 10, n. 4 (ottobre 1993): 336–45. http://dx.doi.org/10.1123/apaq.10.4.336.

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Abstract (sommario):

Attention is drawn to specific practical and ethical concerns that may arise when researchers study responses to vigorous exercise in populations with disabilities. It is argued that the study of such individuals can provide important information regarding responses to exercise by nondisabled people. This thesis is illustrated by selected examples relating to (a) central versus peripheral limitation of oxygen transport, (b) the contribution of muscle pumping to venous return during vigorous exercise, (c) the contribution of sympathetic innervation to aerobic training responses, (d) the ceiling of muscle fiber hypertrophy, (e) the functional demands of daily living, and (f) the responsiveness of young children to aerobic training. It is concluded that exercise physiologists have already learned much about normal reactions to exercise by studies involving those disabilities, but there remains scope for many further investigations exploiting the special characteristics of such populations.

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49

Verschuren, Olaf, Manon Bloemen, Cas Kruitwagen e Tim Takken. "Reference Values for Aerobic Fitness in Children, Adolescents, and Young Adults Who Have Cerebral Palsy and Are Ambulatory". Physical Therapy 90, n. 8 (1 agosto 2010): 1148–56. http://dx.doi.org/10.2522/ptj.20090318.

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BackgroundVery few objective data exist regarding aerobic performance in young people with cerebral palsy (CP). The characterization of aerobic fitness could provide baseline and outcome measures for the rehabilitation of young people with CP.ObjectiveThe objective of this study was to provide reference values for aerobic fitness in a group of children, adolescents, and young adults who had CP and who were classified at Gross Motor Function Classification System (GMFCS) level I or II. Data were collected with 10-m shuttle run tests.DesignThis investigation was a cross-sectional observational study conducted between August 2008 and June 2009.MethodsReference values were established using data from a total of 306 children, adolescents, and young adults who had CP, who were 6 to 20 years old, and who were recruited from 26 rehabilitation centers in the Netherlands, Switzerland, Australia, Canada, and the United States. A total of 211 participants were classified at GMFCS level I (mean age=12.2 years, SD=3.0), and 95 were classified at GMFCS level II (mean age=12.4 years, SD=3.2); 181 were male, and 125 were female. Aerobic fitness was reflected by the level achieved on the 10-m shuttle run tests.ResultsOn the basis of a total of 306 assessments from the 10-m shuttle run tests, 4 reference curves were created.LimitationsThe limitation of this study is the cross-sectional nature of the design.ConclusionsThis study provided height-related reference values for aerobic fitness in children, adolescents, and young adults who had CP, who were 6 to 20 years old, and who were classified at GMFCS level I or II. Generalized additive models for location, scale, and shape were used to construct centile curves. These curves are clinically relevant and provide a user-friendly method for the prediction of aerobic fitness in young people with CP.

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Lindstedt, S. L., e K. E. Conley. "Human aerobic performance: too much ado about limits to V̇O2". Journal of Experimental Biology 204, n. 18 (15 settembre 2001): 3195–99. http://dx.doi.org/10.1242/jeb.204.18.3195.

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SUMMARY Human endurance performance is often evaluated on the basis of the maximal rate of oxygen uptake during exercise (V̇O2max). Methods for overcoming limits to V̇O2max are touted as means for increasing athletic endurance performance. Here, we argue that the respiratory system is well designed for delivering O2 to meet O2 demands and that no single factor is rate-determining for O2 uptake. We show that V̇O2max can vary 5000-fold among mammals, while any limitation to O2 delivery by a single component of the respiratory system affects V̇O2max by 10% or less. Attempts to increase O2 delivery by enhancing one step in the respiratory system are shown to have little effect. Blood doping, hyperoxia and O2 supplementation of high-altitude natives all raise O2 availability substantially to the working muscles, but these treatments increase V̇O2max only minimally. Finally, we argue that O2 uptake is only one of a number of properties important to human aerobic performance.

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