Dissertations / Theses: 'Respiration physiology'

1

Crisp, Andrew John. "Cardiac ventricular receptors and the control of respiration." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241355.

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Paterson, D. J. "Some factors affecting respiration in man and the cat." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329931.

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Howard, Luke Sebastian Geoffrey Eliot. "The effects of prolonged hypoxia on respiration in man." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282330.

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HOIT, JEANNETTE DEE. "AGE AND SPEECH BREATHING (KINEMATICS, PHYSIOLOGY, RESPIRATORY)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183956.

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The present investigation was designed to elucidate the potential influence of age on speech breathing. Toward this end, 30 men representing three widely different age groups (25, 50, and 75 years) were studied. These individuals were carefully selected to meet stringent criteria, the most important of which related to health and physical characteristics. Speech breathing was studied via anteroposterior diameter changes of the rib cage and abdomen. Recordings were made during extemporaneous speaking and reading and during the performance of various chest wall maneuvers used in the measurement of the speech breathing data. In addition to speech breathing, selected measures of general respiratory function were obtained. These included measures of subdivisions of the lung volume and measures of resting tidal breathing. Results indicated that these 30 subjects were representative of other subjects studied with respect to measures of general respiratory function. Subdivisions of the lung volume were found to differ with age in the manner predicted by previous investigations. Age-related differences were most marked for measures of vital capacity and residual volume. By contrast, there were no age-related differences for measures of resting tidal breathing. Several speech breathing measures were found to differ with age. Age-related differences were usually between the 25- and 75-year-old subject groups and less commonly between the 25- and 50-year-old subject groups. For extemporaneous speaking, differences were found for lung volume excursion, rib cage volume initiation (referenced to the rib cage volume associated with the relaxed configuration of the chest wall), number of syllables per breath group, and lung volume expended per syllable (in percent vital capacity). For reading, differences were found for lung volume expended per syllable (in percent vital capacity). Age-related similarities and differences in general respiratory function and speech breathing are discussed in relation to possible underlying mechanisms. In addition, implications are drawn regarding evaluation and management of individuals with speech breathing disorders.

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Hattersley, B. "Dark respiration and carbohydrate metabolism in leaves of Solanum dulcamara L." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384609.

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Al-Kadhomiy, N. K. "Gill development, growth and respiration of the flounder, Platichthys flesus (L.)." Thesis, University of Bristol, 1985. http://hdl.handle.net/1983/f8e6e177-9551-4e58-b76c-02394305e40c.

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Iwarsson, Jenny. "Breathing and phonation : effects of lung volume and breathing behaviour on voice function /." Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4522-5.

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Hart, A. J. "Physiology of growth and respiration during the cell cycles of Bacillus subtilis and Paracoccus denitrificans." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356282.

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Scott, Adrienne S. "Comparison of respiratory sinus arrhythmia integration in athletes and non-athletes." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33924.

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A comparison of heart rate viability and respiratory sinus arrhythmia (RSA) characteristics was performed in 20 athletes and 12 age-matched sedentary controls (CTRL) (22 +/- 2.4 yrs). More specifically, this study examined the role of regular physical activity on the breathing frequency (BF)---RSA amplitude response curve comparing varsity swimmers (SW) to endurance runners (RU) to test the hypothesis that a locomotor-respiratory entrainment resulting from the water-immersion breathing pattern of swimmers would alter their respiratory related cardiac vagal integrative response. Spectral power components of HRV were computed from R-R interval sequences. Five-minute recordings were performed with subjects breathing either at their spontaneous breathing rate, at four breathing cycles less (M4) and four cycles more (P4) than spontaneous. Amplitude and phase of RSA were computed from the sinusoid fitted to the instantaneous heart rate within each breath while the gain of the RSA response was obtained from the slope of the RSA amplitude versus BF. (Abstract shortened by UMI.)

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Tippetts, Trevor Stanley. "Cigarette Smoke Increases Cardiomyocyte Ceramide Accumulation and Inhibits Mitochondrial Respiration." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5596.

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Cigarette smoking is a common and lethal worldwide habit, with considerable mortality stemming from its deleterious effects on heart function. While current theories posit altered blood lipids and fibrinogen metabolism as likely mediators, none have explored the role of the sphingolipid ceramide in exacerbating heart function with smoke exposure. Ceramide production is a consequence of cigarette smoke in the lung, and considering ceramide's harmful effects on mitochondrial function, we sought to elucidate the role of ceramide in mediating smoke-induced altered heart mitochondrial respiration. Lung cells were exposed to cigarette smoke extract and heart cells were exposed to the lung-cell conditioned medium. Adult male mice were exposed sidestream cigarette smoke for 8 weeks with dietary intervention and ceramide inhibition. Ceramides and heart cell or myocardial mitochondrial respiration were determined. Lung cell cultures revealed a robust response to cigarette smoke extract in both production and secretion of ceramides. Heart cells incubated with lung-cell conditioned medium revealed a pronounced inhibition of myocardial mitochondrial respiration, though this effect was mitigated with ceramide inhibition via myriocin. In vivo, heart ceramides increased roughly 600% in adult mice with long-term sidestream cigarette smoke exposure. This resulted in a significant ceramide-dependent reduction in left myocardial mitochondrial respiration, as heart mitochondria from the mice exposed to both smoke and myriocin injections respired normally. These results suggest ceramide to be an important mediator of altered myocardial mitochondrial function with cigarette smoke exposure. Thus, anti-ceramide therapies might be considered in the future to protect heart mitochondrial function with smoke exposure.

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Bevan, David J. (David John). "The effect of dissolved oxygen and water depth on the respiratory behaviour and growth of Clarias macrocephalus (Pisces, Clariidae) /." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65506.

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Moser, Jonathan G. "Cold Season Physiology of Arctic Plants." FIU Digital Commons, 2012. http://digitalcommons.fiu.edu/etd/750.

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The cold season in the Arctic extends over eight to nine months during which ecosystem gas exchange and water balance of arctic plants have been largely unexplored. The overall objective of this thesis was to examine two critical gaps in our knowledge about tundra cold season processes – ecosystem respiration at very low temperatures and water uptake during the winter-spring transition. I determined the temperature response of ecosystem respiration of tundra monoliths down to temperatures as low as can be expected under snow-covered conditions (-15 °C). Temperature responses fit the Arrhenius function well with Q10 values over the range of -15 to 15 °C varying from 6.1 to 4.8. I used deuterium-enriched water (2H2O) as a tracer to evaluate water uptake of evergreen plants at snowmelt when soils are largely frozen. The results revealed that evergreen plants take up water under snow cover, possibly via roots but undoubtedly by foliar uptake.

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Bruhn, Dan. "Plant respiration and climate change effects." Roskilde : Risø National Laboratory, 2002. http://www.risoe.dk/rispubl/PRD/prdpdf/ris-r-1332.pdf.

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Shearman, Julia. "The regulation of respiration on plant growth and development of Fallopia japonica, Japanese knotweed." Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/62040/.

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Fallopia japonica, or Japanese knotweed is a rhizomatous perennial herb native to East Asia; most notably Japan, China and Korea. Upon discovery of this species and subsequent import to Europe in the 1840's, it was considered an esteemed ornamental plant – winning the medal for the ‘most interesting new plant of the year' in 1847. F. japonica soon became known as a menace rather than a champion, when it began to spread throughout its new environment, spreading to gardens and nurseries and regenerating from discarded plant fragments. The species ability to cause environmental damage has earnt it a place in the ‘top 100 world's worst most invasive alien species' list. Commercially available herbicides have proven have little effect on F. japonica, and to be successful require many repeat applications. The plant can grow up to 10 cm per day during the early budding and shoot stage and can easily dominate an environment when left unchecked. A key objective of this research was to determine the biochemical pathways of energy generation particularly during the rapid phase of growth with the longer term goal of identifying potential inhibitors of this process which may have commercial opportunities. Very little research is available regarding the biochemistry of growth of F. japonica, thus detailed protocols were required to be established and optimised prior to biochemical investigations. Mitochondrial isolations and following respiratory activity measurements were performed on F. japonica prepared from naturalised plants. Such mitochondrial samples were found to have a very low respiratory rates when compared to mitochondria isolated from other species such as Arum maculatum. This was confirmed following an analysis of the respiratory complexes via electrophoresis, which revealed that all complexes were of low abundance in comparison with other plant species. Transmission electron microscopy also revealed that the numbers and volumes of mitochondria in budding tissue were considerably fewer and larger than those observed in other rapidly expanding plant tissues - providing further confirmation of the respiratory measurements. In an attempt to overcome the small yield associated with mitochondrial isolations, research is also presented on the generation, optimisation and characterisation of suspension cultures from F. japonica explants. Suspension cultures were shown to have almost identical characteristics in terms of mitochondrial protein complement and respiratory capacity as observed in bud and shoot isolations. Preliminary mass spectroscopy data indicated a large proportion of ATP synthase subunits were present in the isolated mitochondrial fractions from leaf, bud, shoot and suspension cultures. Glycolytic analysis of fractions isolated from suspension cultures were also undertaken the outcome of which are discussed in terms of the energy generation pathways within F. japonica and the implications of how such pathways may be controlled.

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Sekharan, Soja. "Aged soybean (Glycine max [L.] Merrill) seeds their physiology and vigor assessment /." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1135809134.

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Frise, Matthew. "Iron deficiency and human hypoxia physiology." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:a6cbaa64-eed4-43db-8a2f-2826e6bbd249.

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This thesis is concerned with a very common disorder of iron homeostasis: iron deficiency. The specific focus is the manner in which iron deficiency influences physiological responses to hypoxia in humans. This work is predicated on observations made over many decades in vitro and in vivo, suggesting that variations in the bioavailability of iron have important consequences for certain biological processes known to depend on oxygen availability. Three separate but related studies together form the basis for this thesis. The first two, Study A and Study B, adopt a similar approach in recruiting healthy volunteers who differ according to iron status, yielding iron-deficient and iron-replete groups in both cases. In Study A, the behaviour of the pulmonary circulation is investigated during a sustained hypoxic exposure, before and after an intravenous infusion of iron. In Study B, skeletal muscle metabolism is explored, both at the level of high-energy phosphate metabolism and the integrated physiological responses to exercise on a cycle ergometer. In the third study, Study C, a different approach is taken, recruiting patients with chronic obstructive pulmonary disease (COPD), and exploring the prevalence and associations of iron deficiency in this condition. Chapters 2 and 3 describe experiments using sustained hypoxia in a normobaric chamber, during which the pulmonary circulation is assessed non-invasively using Doppler echocardiography. These reveal augmented hypoxic pulmonary vasoconstriction (HPV) in iron-deficient individuals, who also exhibit greater sensitivity to the effects of an infusion of intravenous iron. Additionally, the way in which certain circulating mediators important for iron haemostasis change over the course of these hypoxic exposures, and how iron status influences these responses, is explored. Chapter 4 reports the findings of experiments using 31P-magnetic resonance spectroscopy and cardiopulmonary exercise testing, which demonstrate abnormal whole-body metabolism in iron-deficient individuals during large muscle-mass exercise, despite the absence of a clear defect in mitochondrial oxidative phosphorylation. Intravenous iron is found to have significant effects to alter the lactate threshold in healthy individuals, but the effects are more striking in iron-deficient individuals. Collectively, these experiments imply that iron deficiency promotes a more glycolytic phenotype. Chapter 5 explores iron deficiency in COPD, a condition in which pulmonary vascular disease, hypoxia and skeletal muscle dysfunction coexist, and examines some of the difficulties in assessing iron status in the setting of a chronic inflammatory disorder. Iron deficiency is found to be common, and unexpectedly associated with significantly more severe hypoxaemia, in patients with COPD. Possible reasons for these findings, and their clinical implications, are considered. Chapter 6 provides a summary of the main conclusions to be drawn from the studies presented in this thesis.

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Wisse, Gesine Alida. "The role of sodium in the growth, respiration and membrane transport of Pseudomonas doudoroffii /." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65517.

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18

Jordan, Amy Selina. "The control of respiration and upper airway muscle activity in healthy young men and women." Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phj812.pdf.

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"May 2002." Bibliography: leaves 123-144. Aspects of the control of ventilation and an upper airway dilator muscle (genioglossus) are compared between healthy men and women, in an attempt to identify a gender difference that may contribute to the high male prevalence of sleep apnea.

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Zachrich, Timothy P. "Max VO₂ and ventilatory threshold in university level hockey players." Bowling Green, Ohio : Bowling Green State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=bgsu1210886896.

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Altman, Mary Ellen 1962. "SPEECH BREATHING KINEMATICS IN WOMEN." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277081.

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Rowe, Jack E. "Effect of inspiration to expiration ratio on autonomic arousal /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9842562.

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Gough, Christopher Michael. "Quantification and Physiology of Carbon Dynamics in Intensively Managed Loblolly Pine (Pinus taeda L.)." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11232.

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Loblolly pine (Pinus taeda L.) occupies 13 million hectares in the United States and represents a critical component of the global carbon (C) cycle. Forest management alters C dynamics, affecting the C sequestration capacity of a site. Identifying drivers that influence C cycling, quantifying C fluxes, and determining how management alters processes involved in C cycling will allow for an understanding of C sequestration capacity in managed forests. Objectives of the first study included (1) investigating environmental, soil C, root, and stand influences on soil CO2 efflux on the South Carolina coastal plain and (2) quantifying soil CO2 efflux over a rotation in loblolly pine stands located on the South Carolina coastal plain and the Virginia piedmont. In relation to the first objective, temporal variation in soil CO2 efflux was most highly related to soil temperature. Spatial and temporal variability in soil CO2 efflux was weakly related to soil C and root biomass, and not related to coarse woody debris, stand age, stand volume, or site index [Chapter 2]. Soil CO2 efflux was not related to stand age on the South Carolina sites while efflux was positively related to age on the Virginia sites. Cumulative soil C efflux on the South Carolina sites over 20 years is an estimated 278.6 Mg C/ha compared with an estimated 210.9 Mg C/ha on the Virginia sites [Chapter 3]. Objectives of the second study were (1) to investigate short-term effects of fertilization on processes permitting enhanced growth in loblolly pine and (2) to determine the short-term effects of fertilization on autotrophic, heterotrophic, and soil respiration. Major results from the study include the finding that fertilization caused a transient rise in photosynthetic capacity, which paralleled changes in foliar nitrogen. Leaf area accumulation and enhanced growth following fertilization was partly due to enhanced C fixation capacity [Chapter 4]. Fertilization altered the contribution of autotrophic and heterotrophic respiration to total soil CO2 efflux. Enhanced specific root respiration was short-lived while suppressed microbial respiration following fertilization was maintained over the course of the nearly 200-day study. Respiring root biomass growth increased total soil respiration over time [Chapter 5].
Ph. D.

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Song, Sarah M. "Respiration and whole body lactate in wild and aquacultured penaeid shrimp challenged with hypoxia and the bacterial pathogen Vibrio campbellii." Thesis, College of Charleston, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1601676.

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Estuarine organisms, such as juvenile penaeid shrimp, experience fluctuating oxygen pressures on a daily basis. In coastal waters of the southeastern United States, severe hypoxia (< 4–6 kPa) is common in the summer, also a time during which bacterial concentrations in seawater are high. In response to invading bacteria, crustaceans mount an immune defense resulting in aggregations of circulating hemocytes. These aggregates can be trapped in and obstruct hemolymph flow through the gills, inhibiting oxygen uptake. Hypoxia itself is also known to inhibit immune function. In this study we investigated some key characteristics of penaeid shrimp that are likely to be associated with their ability to cope with hypoxia and bacterial infection. We compare critical Po₂, the oxygen pressure below which oxygen uptake depends on available ambient oxygen, in two commercially important shrimp species: wild Litopenaeus setiferus, the Atlantic white shrimp, and aquacultured Litopenaeus vannamei, the Pacific whiteleg shrimp. We also compare whole body lactate concentrations following acute exposure to severe environmental hypoxia (5.3 kPa), and injection with a sub-lethal dose of bacteria ( Vibrio campbellii 90-69B3), in aquacultured L. vannamei and in wild-caught Farfantepenaeus duorarum, the Atlantic pink shrimp. LD₅₀ tests indicate that the virulence of V. campbellii in L. setiferus (LD₅₀ = 6.4 × 10⁵ CFU g⁻¹ shrimp) is similar to that previously determined in L. vannamei (LD₅₀ = 3.06 × 10⁵ CFU g⁻¹ shrimp). We found no difference between L. vannamei and L. setiferus in critical Po₂, which fell between 3.5–5.2 kPa in both species. Whole body lactate concentration was measured in shrimp held in normoxia (>16 kPa) or hypoxia and injected with saline or bacteria. There were no effects of exposure in L. vannamei, however lactate concentration in F. duorarum increased by 60% in shrimp exposed concurrently to hypoxia and injected-bacteria, compared to saline-injected shrimp exposed to hypoxia and Vibrio-injected shrimp exposed to normoxia. This is consistent with previous findings in our lab, that hemocyanin in L. vannamei has a higher concentration and O₂ affinity, resulting in better tissue oxygenation, than that in wild species of Atlantic shrimp. These data suggest that aquacultured L. vannamei has an adaptive advantage over at least one species of wild penaeid shrimp in coping with hypoxia and bacterial infection.

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Fennir, Mohamed A. "In situ estimation of respiration and transpiration rates of stored fruits and vegetables." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ29691.pdf.

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Allen, Leon Akila Glynne. "Effect of temperature on the physiology of two exotic frogs: possible causes of distribution." Thesis, University of Canterbury. Biological Sciences, 2015. http://hdl.handle.net/10092/10822.

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Two Australian frogs were introduced to New Zealand over 100 years ago. Since their introduction they have become widespread and well established with Litoria ewingii being more prevalent in alpine and cooler areas of New Zealand, while Litoria raniformis is found in more temperate coastal areas. Very little physiological data exists for these frogs and aside from their distribution not much is known about them in New Zealand. Thus the effects of thermal acclimation and temperature change on respiration and locomotion were examined in these two exotic frogs. The more terrestrial and alpine dwelling L. ewingii was found to be able to thermally acclimate its respiration performance, where respiration was highest when acclimation temperature matched test temperature. It was also able to thermally acclimate its locomotory performance, jumping significantly further at lower temperatures, however, acclimation to high temperatures impacted its jump performance at cold temperatures. The frog L. raniformis was found to only be able to thermally acclimate its respiration and locomotion to high temperatures, as performance at low temperatures was often poor. The data shows that L. ewingii is a cold temperate frog rather than a warm habitat frog, while L. raniformis is an animal adapted to warm temperatures. From this we can begin to see the effect that temperature has on the physiology of these two exotic frogs and the major role that temperature may be playing in driving the differences seen in the distribution of these two species in New Zealand.

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Titulaer, William A. "Respiration physiology and the gill structure of the New Zealand freshwater crayfish Paranephrops zealandicus (White 1847) (Decapoda: Parastacidae)." Thesis, University of Canterbury. Zoology, 1995. http://hdl.handle.net/10092/5955.

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The New Zealand freshwater crayfish P. zealandicus emerges from water and exposes it's respiratory surface to desiccation and collapse, it's haemolymph to acid-base disturbance and it's tissues to hypoxia. This study was to investigate the respiratory system during aerial respiration. P. zealandicus has 20 gills, a rudimentary gill and an epipodite (20 + r + ep). Two types of gill filament were identified; a respiratory filament with a cuticle 0.7µm thick, an afferent and efferent vessel and haemolymph lacunae adjacent to the cuticle, and an ion regulating filament with a cuticle 1.2µm thick in which the cells adjacent to the cuticle contain all the organelles and membranes which are associated with ion regulating tissues. It was found that P. zealandicus emerged from the water voluntarily. There was no significant difference in the frequency of emersion by solo crayfish at 18°C, crayfish pairs at 18°C, solo crayfish experiencing hypoxia at l8°C, and solo crayfish at 24°C. Solo crayfish and crayfish pairs recorded a significantly higher level of emersion activity at night than during the daytime. At 15°C the settled rate of oxygen consumption in air, 1.03± 0.03 µmol.g-1 .h-1 (± 1 sem), was not significantly different from the settled rate of oxygen consumption in water, 1.10± 0.03 µmol. g-1. h-1. Oxygen consumption in water was compromised by declining external oxygen tension below PCR1T (41 - 44 Torr). At PCR1T the oxygen consumption was 1.06 ± 0.05 /lffi01.g-1 .h-1 At only one time in 48 hours aerial respiration was haemo1ymph arterial oxygen tension below PCRIT .This was after 12 hours aerial respiration, and was associated with an increase in lactate concentration to 5 mmol.1-1 , which was, however, removed during the subsequent 12 hours aerial respiration. The crayfish were not considered to be experiencing internal hypoxia for the remainder of the 48 hours in air. The total oxygen consumed during 8 hours recovering from aerial respiration was similar to the total oxygen consumed during the 8 hours settling at the beginning of the experiment, indicating no measurable oxygen debt accumulated during 48 hours aerial respiration. After emersion into air the crayfish experienced a respiratory acidosis, and an elevated arterial carbon-dioxide tension. Total haemolymph carbonates, measured 12 hours after emerging from water indicated compensation by metabolic alkalosis. Upon returning to the water the crayfish experienced a respiratory alkalosis. Rapidly declining arterial carbon-dioxide tension, and total haemolymph carbonates indicated compensation by metabolic acidosis. The measured in vitro non-bicarbonate buffer capacity was -3.8 mmol.-1 . (pH unit)-1. During the 48 hours in air the pH was regulated between 7.55 and 7.68 with the pH significantly more alkaline at 8 pm than at 8 am, by 0.1 pH units. At 15°C, the solubility of oxygen in haemolymph, ±PLASMAO2, was 1.8 µmol.1-1.Torr-1, and at an oxygen tension of 150 Torr the total haemolymph oxygen content was 1 mmol.1-1. There was a Bohr effect, ΔlogP50/ΔpH, of - 0.48 to - ,0.96. Settled in water at 15°C, with a haemolymph carbon-dioxide tension of 2.6 Torr, the crayfish haemocyanin was 50 % saturated at an oxygen tension of 12 Torr. Crayfish kept at 15°C had an oxygen content when the haemocyanin was 50 % saturated, and a total oxygen content, which were 50 % higher than crayfish from water at 9.5°C. Estimates of limitation to diffusion/perfusion, Ldiff, in water of 0.76, and in air of 0.98, indicate that respiration in P. zealandicus is diffusion limited. The respiratory frequency, fR, and heart frequency, fH, of settled crayfish in air was not significantly different from settled crayfish in water. The fH during aerial respiration demonstrated less fluctuation than fH in control crayfish in water, and the fR of crayfish in air was more variable than the fR in control crayfish in water. The control crayfish settled in water exhibited a significant diel fluctuation in fR and fH, with high fR and fH recorded in the evening and low fR and fH in the morning. Several activities and changes measured in this study have a diel rhythm. A dusk pH recorded at 8 pm. was 0.1 pH units more alkaline than a dawn pH recorded at 8 am. Settled in water, P. zealandicus exhibits a diel fluctuation in fR and fH, with high fR and fH recorded in the evening and low fR and fH in the morning. At 18°C, solitary crayfish and crayfish pairs show higher levels of emersion activity at night than during the daytime. The results indicate that crayfish P. zealandicus has a respiratory system which can cope with aerial respiration, and some of the activities and changes reported in this study have a diel rhythm.

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Leaver, James Thomas. "The enzymologyand physiology of nitrate and selenate reduction/respiration in Enterobacter cloacae SLD1a-1 and Aeromonas hydrophila ATCC7966." Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445542.

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Word, James Mabry. "Physiological adjustments to aestivation and activity in the cocoon-forming frogs Cyclorana platycephala and Cyclorana maini." University of Western Australia. School of Animal Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0254.

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The desert-adapted frogs Cyclorana platycephala and Cyclorana maini survive long periods of inhospitably hot and dry conditions by retreating underground and aestivating. While aestivating they suspend food and water intake as well as physical activity, depress their metabolic rate by ~80 %, and form cocoons that protect them against desiccation. How these frogs function during this exceptional state is largely unknown. This work characterized a number of physiological parameters in three metabolic states spanning their natural metabolic range: during aestivation (depressed metabolism), at rest (normal metabolism), and where possible, during exercise (elevated metabolism). The primary objective was to identify by comparison, physiological adjustments in these parameters to metabolic depression, as well as the scope of these parameters in frogs capable of aestivation. The parameters measured for C. maini were (a) the glucose transport kinetics and (b) the fluid balance of an extensive number of their individual organs. For C. platycephala, the parameters measured were (a) the activity of the cardiovascular system as indicated by heart rate and blood pressure and (b) the roles of pulmonary and cutaneous respiratory systems in gas exchange

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Blank, Tara M. "Cardio-Respiratory Ontogeny and the Transition to Bimodal Respiration in an Air Breathing Fish: Morphological and Physiological Development in Normoxia and Hypoxia." Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc11056/.

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As selection pressures exist for not only adults, but for every life history stage, it is important to understand how environmental factors shape developing animals. Despite the significance placed on aquatic hypoxia as a driving force in the evolution of air breathing, this is the first known study to examine the effects of hypoxia on cardio-respiratory ontogeny of an air breathing fish. Blue gouramis are obligatory air breathing fish that possess a labyrinth-like structure that serves as the air breathing organ. Gouramis were reared for up to 90 d in normoxia or hypoxia, and morphological and physiological development was observed. Hypoxic larvae had increased lamellar and labyrinth organ surface areas. Bradycardia and increased gill ventilation rates were observed when larvae from either rearing group were briefly exposed to hypoxia. Hypoxic larvae also showed a reduced heart rate and gill ventilation rate in the absence of a hypoxic stimulus, possibly indicative of a more comprehensive, long-term respiratory plasticity. The similarity of routine oxygen consumption between rearing groups suggests that metabolic demand did not change for hypoxic larvae, but that they were more efficient at oxygen acquisition. This is further supported by increased resistance time of hypoxic gouramis to extreme hypoxia. The onset of air breathing was between 20 and 25 d post-fertilization, and was not affected by either rearing or exposure environment. It may be that this behavior is associated with the inability of smaller larvae to successfully overcome water surface tension, rather than with the necessity of aerial respiration at this stage. Hypoxia is commonly experienced by most air breathing fishes, and studies of hypoxia-induced developmental effects may provide critical insights into the evolution of air breathing. The studies presented here provide novel data on the plasticity of cardio-respiratory development of an air breathing fish reared in hypoxia, and can serve as a solid foundation for future studies.

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Dhingra, Rishi R. "Intrinsic and Extrinsic Mechanisms Regulate the Variability of the Respiratory Rhythm in Rodents." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1383514460.

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31

Scheepers, Ilana. "The influence of genetic manipulation of cytosolic aldolase (ALDc) on respiration in sugarcane." Thesis, Link to the online version, 2005. http://hdl.handle.net/10019/1190.

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32

Lundmark, Maria. "Low temperature acclimation in plants : alterations in photosynthetic carbon metabolism." Doctoral thesis, Umeå : Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1333.

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Zervopoulos, Peter C. (Peter Cosmas). "Relationship Between Ventilation and Oxygen Uptake at 40% And 85% of Peak Oxygen Uptake in 18-35-Year-Old Women Using the Arm Crank Ergometer." Thesis, North Texas State University, 1988. https://digital.library.unt.edu/ark:/67531/metadc500377/.

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This study investigated whether or not a relationship exists between ventilation and oxygen uptake at 40% and 85% of V02 peak intensity in 30 upper body fit and 30 unfit 18- 35-year-old women. The correlations between ventilation and oxygen uptake at 40% of peak intensity for the fit group (r = -.51) and the unfit group (r = -.48) were modestly negative. At 85% intensity the relationship between ventilation and oxygen uptake in the two groups was -.44 and -.66, respectively. The lower correlations between ventilation and oxygen uptake observed at the 85% level of peak intensity among the unfit group could be due to a lower ventilatory threshold (66% = fit; 49% = unfit), lesser local muscle changes, along with reduced lactate and C02 management; all of which would be improved with training.

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Pereira, De Sa Rui Carlos. "Respiration and cardio-respiratory interactions during sleep in space: influence of gravity." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210416.

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Le principal objectif de ce travail est l’étude de l’influence de la pesanteur sur la mécanique

respiratoire et le contrôle de la respiration, ainsi que sur les interactions cardio-respiratoires pendant les différents stades du sommeil.

Le chapitre introductif présente le contexte général et les objectifs de la thèse. Des sections abordant le sommeil, la respiration, et l’interaction cardio-respiratoire y sont présentées, résumant l’état actuel des connaissances sur les effets de la pesanteur sur chacun de ces systèmes.

Dans le deuxième chapitre, l’expérience “Sleep and Breathing in microgravity”, qui constitue la source des données à la base de ce travail, est présentée en détail.

L’étude des signaux de longue durée requiert avant tout de disposer d’outils performants

d’analyse des signaux. La première partie de la thèse présente en détail deux algorithmes :un

algorithme de détection automatique d’événements respiratoires (inspiration / expiration)

basé sur des réseaux neuronaux artificiels, et un algorithme de quantification de l’amplitude

et de la phase de l’arythmie sinusale pendant le sommeil, utilisant la méthode des ondelettes.

La validation de chaque algorithme est présentée, et leur performance évaluée. Cette partie

inclut aussi des courtes introductions théoriques aux réseaux de neurones artificiels ainsi

qu’aux méthodes d’analyse temps–fréquence (Fourier et ondelettes).

Une approche similaire à celle utilisée pour la détection automatique d’événements respiratoires a été appliquée à la détection d’événements dans des signaux de vitesse du sang

dans l’artère cérébrale moyenne, mesures obtenues par Doppler transcrânien. Ceci est le

sujet de la thèse annexe.

Ces deux algorithmes ont été appliqués aux données expérimentales pour extraire des

informations physiologiques quant à l’impact de la pesanteur sur la mécanique respiratoire et

l’interaction cardio-respiratoire. Ceci constitue la deuxième partie de la thèse. Un chapitre

est consacré aux effets de l’apesanteur sur la mécanique respiratoire pendant le sommeil.

Ce chapitre a mis en évidence, pour tous les stades de sommeil, une augmentation de la

contribution abdominale en microgravité, suivi d’un retour progressif vers des valeurs observées avant le vol. L’augmentation initiale était attendue, mais l’adaptation progressive

observée ne peut pas être expliquée par un effet purement mécanique, et nous suggère la

présence d’un mécanisme d’adaptation central. Un deuxième chapitre présente les résultats

comparant l’arythmie sinusale pendant le sommeil avant le vol, en apesanteur et après le retour sur terre. Le rythme cardiaque pendant le sommeil dans l’espace présente une moindre

variabilité. Les différences NREM–REM observées sur terre pour les influences vagales et sympathiques sont accentuées dans l’espace. Aucun changement significatif n’est présent pour

le gain et la différence de phase entre les les signaux cardiaque et respiratoire en comparant

le sommeil sur terre et en apesanteur.

La dissertation termine par une discussion générale du travail effectué, incluant les prin-

cipales conclusions ainsi que les perspectives qui en découlent.
Doctorat en Sciences biomédicales et pharmaceutiques
info:eu-repo/semantics/nonPublished

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Wallace, Nathan Christopher. "Metabolic and Physiological Determinants in Listeria monocytogenes Anaerobic Virulence Regulation." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1543424768026244.

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Manley, Elizabeth. "Apneic Bradycardia : terrestrial and aquatic responses in man under working conditions." Thesis, Rhodes University, 1989. http://hdl.handle.net/10962/d1001838.

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The focus of this research was the reappraisal in physiological and psychophysical terms of current equivocal theories regarding the onset, course and termination of apneic bradycardia. Sixteen healthy male subjects participated in four separate testing sessions . Maximal oxygen consumption (VO₂ max) was measured on land and underwater using an identical direct, continuous progressive cycle ergometer test. On each of two other occasions subjects exercised in either environment at 50, 70 and 90% of the appropriate VO₂ max, during which time heart rate was continuously recorded. An initial apneic bout at each exercise intensity was followed by performance of the same workload without apnea for an equivalent period of time. Ratings of perceived exertion (RPE) were also monitored. While apneic bradycardia occurred at each exercise intensity studied underwater, it was apparent only at 50% VO₂ max on land. With the exception of between 50 and 90% VO₂ max on land, the mean apneic heart rates did not differ with varying exercise intensity (p<0.05); nor did the lowest heart rate recorded, although this was lower underwater than on land. Apart from 70% VO₂ max on land, apneic heart rates were lower than the equivalent values measured during exercise without apnea. Land and underwater heart rates during apneic and non-apneic conditions did not differ until 90% VO₂ max. The effects of increasing exercise intensity upon the onset of bradycardia were evident in that it occurred earlier at 50% VO₂ max underwater than at the heavier workloads, and only at 50% VO₂ max on land. The mean breath-hold duration did not differ between the land and underwater environments, nor was it affected by increasing exercise intensity. The order in which breath-holds was performed did not alter the length of apnea. Land and underwater RPE did not differ and increased with increasing exercise intensity in both environments. During apneic exercise RPE was greater than the equivalent exercise without apnea. Twelve of the original 16 subjects were divided equally into two groups on the basis of vital capacity expressed relative to body surface area. Vital capacity was measured during the first laboratory session. Neither the mean heart rate response to apneic exercise at 50% V0₂ max in both environments, nor the lowest heart rates recorded differed between groups, prompting the conclusion that lung volume did not affect apneic bradycardia. Despite a longer breath-hold duration for Group A (large relative lung volume) than Group B (small relative lung volume), the onset point of bradycardia was the same for either group when expressed relative to total breath-hold duration

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Brown, Anne Christine 1962. "Effects of salinity and temperature on the respiratory physiology of the Dungeness crab, Cancer magister, during development." Thesis, Thesis (Ph. D.)--University of Oregon, 1991, 1991. http://hdl.handle.net/1794/9845.

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Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 172-183).
Cancer magister, the Dungeness crab, occurs in different habitats during its life cycle, habitats which vary widely in the magnitude of salinity and temperature changes. Cancer magister hemocyanin also changes in structure and oxygenation properties during development. The following question was considered in this thesis: what are the effects of environmental salinity and temperature on metabolic rates, ionic and osmotic regulation and hemocyanin oxygen affinity in Q. magister during development. Metabolic rates and hemolYmph ionic and osmotic concentrations were measured in the megalopa, 1st juvenile, 5th juvenile and adult crab eight hours after acute exposure to 100% seawater (=32 ppt), 75% seawater and 50% seawater at both 10°C and 20°C. The oxygen binding properties of the whole hemolymph from these stages in 100% seawater at 10°C was determined. The effects of calcium and magnesium on the oxygen affinity of purified hemocyanin from different stages were also determined. In 100% seawater, routine metabolic rates of the four stages scale with body mass over the size range, 0.05 gm to 500 gm. The Q10 (10°C to 20°C) for the megalopa is higher in 75% seawater and 50% seawater than in 100% seawater. For the 1st juvenile, 5th juvenile and adult the Q10 values (10°C to 20°C) are independent of salinity. The megalopa, 1st juvenile and 5th juvenile are weaker regulators of hemolymph chloride, sodium and osmotic concentrations than the adult. The megalopa and adult, unlike the 1st juvenile and 5th juvenile, strongly regulate hemolymph calcium in reduced salinity. In 100% seawater hemolymph magnesium is significantly higher in the megalopa, 1st juvenile and 5th juvenile than in the adult. The oxygen affinities of whole hemolymph from the four stages are indistinguishable when adjusted for endogenous L-lactate concentrations; the Bohr coefficients are not significantly different among stages. The effect of magnesium on oxygen affinity of purified adult hemocyanin is influenced by proton concentration; the effect of calcium is independent of proton concentration. In 100% seawater, endogenous inorganic ion concentrations in the whole hemolymph of the various stages reduce the intrinsic stage specific differences in hemocyanin oxygen affinity.

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Nilsson, Lena. "Respiratory monitoring using reflection mode photoplethysmography : clinical and physiological aspects /." Linköping : Dept. of Medicine and Care, Univ, 2005. http://www.bibl.liu.se/liupubl/disp/disp2005/med898s.pdf.

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39

Claure, Nelson Remberto. "Microcomputer-based system for the study of the respiratory system in newborns." FIU Digital Commons, 1990. http://digitalcommons.fiu.edu/etd/2382.

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A useful understanding of the respiratory system of premature infants and the factors contributing to different physiological mechanisms and diseases requires extensive clinical research. This project is the result of a need for a fast and reliable system to process the information obtained from biological sources and to obtain results from which different hypothesis can be tested. This document presents a description of one such system and its different subsystems. It describes the biosignals of interest as well as the stages they have to go through in order to obtain an accurate and valid analysis. The system is hardware and software oriented. The system hardware is subdivided into instrumentation system, which is used to pick up and condition the signals, and a data acquisition, monitoring and storage system, where the signals are digitized and stored for later processing. The system software, which is the basic and principal component of the project, participates in the hardware control for the data acquisition, storage and monitoring, as well as the posterior stages of signal processing and analysis, which constitute the key of the system. The biosignals mentioned above can be classified as muscular or EMG, respiratory, chest wall motion, and cardiac signals. The muscular signals are obtained from measuring the electrical activity of the muscles participating in the process of ventilation and the respiratory signals reflect mechanical characteristics of the lungs and airway passages, the chest wall motion signals give a measurement to evaluate the chest wall stability, and the cardiac signals which are measurements of the electrical activity irradiated by the cardiac muscle. These biosignals require extensive processing, especially the EMG signals, before analysis. The signal processing stage uses digital signal processing techniques which were developed or adapted for this purpose. The signal analysis stage is based on research protocols and physical relations to evaluate different respiratory parameters. Special data and file handling software was developed and applied as well as graphics software, to accomplish the stages mentioned above.

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Almgren, Birgitta. "Endotracheal Suction a Reopened Problem." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4798.

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41

Appelberg, Jonas. "Ventilation and Lung Volume During Sleep and in Obstructive Sleep Apnea." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3363.

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42

Matott, Michael Patrick. "The Effects of Oxygen on the Electrophysiology of CO2/H+-Chemosensitive and -Insensitive Neurons of the Solitary Complex of the Rat." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4148.

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This study tested the hypothesis that decreasing the control O2 level from 95% to 40% (5% CO2 + 55% N2) maintains viability in caudal solitary complex (cSC) neurons in transverse slices (~300-400ꝳ) prepared from neonatal rat (P2-22) maintained at 32-34°C. The underlying rationale is to reduce exposure to redox and nitrosative stimuli generated during several hours of exposure to 95% O2 that produces a tissue O2 tension throughout the slice which is in excess of 203 kPa (2.0 atmospheres absolute,ATA) oxygen. Whole cell recordings of cSC neurons maintained in 40% O2 exhibited spontaneous firing and had similar membrane potentials (Vm) and input resistances (Rin) as cSC neurons maintained in 95% O2. Neurons maintained in 40% O2, however, had significantly lower intrinsic firing rates than those maintained in 95% O2. 67% of neurons maintained in 40% O2 control were stimulated by hyperoxia, compared to 81% of neurons maintained in 95% O2 that were stimulated by reoxygenation from relative hypoxia. cSC neurons maintained in 40% O2 also exhibited CO2/H+-sensitivity, including CO2/H+-excitation (31%) and CO2H+-inhibition (31%) and most CO2/H+-sensitive neurons were also stimulated by hyperoxia and reoxygenation or inhibited by lower O2. It is also suggested that acute exposure to lower concentrations of O2 may increase the incidence of CO2-inhibited cSC neurons. Anoxia reduced or eliminated all firing in essentially all cSC neurons. Our findings indicate that brainstem slice viability is retained in 40% O2 control and that hyperoxia is a general stimulant of many cSC neurons, including chemosensitive neurons. We therefore recommend that 40% O2 be used for brainstem electrophysiology studies.

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43

Siekemeyer, Leah C. "Inspiratory Muscle Strength Training in Upper Airway Obstruction." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1306417918.

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44

Thamrin, Cindy. "Measurement of lung function using broadband forced oscillations /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0103.

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45

Beyer, Benoit. "Contribution à la modélisation 3D du thorax humain durant le mouvement respiratoire : analyse in vivo de la cinématique des articulations du thorax." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1309/document.

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La respiration est un phénomène vital qui implique une synergie entre diverses structures anatomiques qui constituent le thorax. La physiologie articulaire reste un parent pauvre de la physiologie et la littérature concernant la quantification de la cinématique 3D des articulations du thorax durant le mouvement respiratoire est rare. Ce travail se concentre sur le développement et l'application d'une méthodologie permettant de répondre à cet objectif. La méthode développée combine le traitement de données tomodensitométriques réalisées à trois volumes pulmonaires différents et des techniques d'infographies. Les amplitudes (ROMs) et axes de mouvements (axe hélicoïdaux moyen, AHMs) ont été obtenus au niveau des articulations costo-vertébrales de 12 sujets asymptomatiques. En résumé, les amplitudes diminuent graduellement dans les étages inférieurs ; le volume pulmonaire et l'étage costal influencent significativement les amplitudes costales ; l'orientation des AHMs ne diffère pas entre les étages costaux. En complément, la méthode a été appliquée pour un échantillon de 10 patients atteints de mucoviscidose. La condition pathologique influençait significativement les amplitudes de mouvements mais pas l'orientation des AHMs. Enfin, le déplacement sternal, les variations de l'angle sternal et la cinématique des articulations sternocostales a été analysée. Les déplacements angulaires des côtes par rapport au sternum diminuaient dans les étages inférieurs comme au niveau des articulations costo-vertébrales. L'orientation des AHMs des articulations sternocostales ne différait pas entre les étages. Une corrélation linéaire a été mise en évidence entre les déplacements verticaux du sternum et les amplitudes de mouvement costales au niveau costo-vertébral et sternocostal. Ce travail contribue de façon substantielle à la modélisation 3D du thorax humain durant le mouvement respiratoire d'un point de vue qualitatif et quantitatif
Breathing is a vital phenomenon that implies synergy of various anatomical structures that constitute the thorax. Joint physiology remains a relatively poorly-known component of the overall thorax physiology. Quantitative literature related to in vivo thorax kinematics during breathing is scarce. The present work focuses specifically on developing and applying a methodology to reach this goal. The developed method combined processing of CT data obtained at different lung volumes and infographic techniques. Detailed ranges of motion (ROMs) and axes of movement (mean helical axes, MHAs) were obtained at costovertebral joints in 12 asymptomatic subjects; rib ROMs gradually decrease with increasing rib number; lung volume and rib level have a significant influence on rib ROM; MHAs did not differ between rib levels. In addition, the method was applied on a sample of 10 patients with cystic fibrosis. The pathological condition significantly influenced CVJ ROMs while the orientation of the MHAs did not differ. Finally, the sternal displacement, sternal angle variations and sternocostal joints (SCJ at rib1 to 7) kinematics during breathing motion were analyzed. Rib ranges of motion relative to sternum decreased with increasing rib number similarly to CVJ. Orientation of the MHAs did not differ between SCJ levels. A significant linear correlation was demonstrated between sternum vertical displacement and rib ranges of motion at both CVJ and SCJ. The present work substantially contributes to 3D modelling of human thorax in breathing at a joint level both qualitatively and quantitatively

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46

Birk, Matthew A. "Ecophysiology of Oxygen Supply in Cephalopods." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7265.

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Cephalopods are an important component of many marine ecosystems and support large fisheries. Their active lifestyles and complex behaviors are thought to be driven in large part by competition with fishes. Although cephalopods appear to compete successfully with fishes, a number of their important physiological traits are arguably inferior, such as an inefficient mode of locomotion via jet propulsion and a phylogenetically limited means of blood-borne gas transport. In active shallow-water cephalopods, these traits result in an interesting combination of very high oxygen demand and limited oxygen supply. The ability to maintain active lifestyles despite these metabolic constraints makes cephalopods a fascinating subject for metabolic physiology. This dissertation focuses on the physiological adaptations that allow coleoid cephalopods to maintain a balance of oxygen supply and demand in a variety of environmental conditions. A critical component of understanding oxygen supply in any animal is knowing the means of oxygen delivery from the environment to the mitochondria. Squids are thought to obtain a fairly large portion of their oxygen via simple diffusion across the skin in addition to uptake at the gills. Although this hypothesis has support from indirect evidence and is widely accepted, no empirical examinations have been conducted to assess the validity of this hypothesis. In Chapter 2, I examined cutaneous respiration in two squid species, Doryteuthis pealeii and Lolliguncula brevis, by using a divided chamber to physically separate the mantle cavity and gills from the outer mantle surface. I measured the oxygen consumption rate in the two compartments and found that, at rest, squids only obtain enough oxygen cutaneously to meet demand of the skin tissue locally (12% of total). The majority of oxygen is obtained via the traditional branchial pathway. In light of these findings, I re-examine and discuss the indirect evidence that has supported the cutaneous respiration hypothesis. Ocean acidification is believed to limit the performance of squids due to their exceptional oxygen demand and pH-sensitivity of blood-oxygen binding, which may reduce oxygen supply in acidified waters. The critical oxygen partial pressure (Pcrit), defined as the PO2 below which oxygen supply cannot match basal demand, is a commonly reported index of hypoxia tolerance. Any CO2-induced reduction in oxygen supply should be apparent as an increase in Pcrit. In Chapter 3, I assessed the effects of CO2 (40 to 140 Pa) on the metabolic rate and Pcrit of two squid species: Dosidicus gigas and Doryteuthis pealeii. Carbon dioxide had no effect on metabolic rate or hypoxia tolerance in either species. Furthermore, considering oxygen transport parameters (e.g. Bohr coefficient, blood P50) and blood PCO2 values from the literature, I estimated an increase in seawater PCO2 to 100 Pa (≈1000 μatm/ppmv) would result in a maximum drop in hemocyanin-O2 saturation by 6% at normoxia and a Pcrit increase of ≈1 kPa (≈5% air saturation) in the absence of active extracellular pH compensation. Such changes are unlikely given the capacity for acid-base regulation in many cephalopods. Moreover, this estimated change is within the 95% confidence intervals of the Pcrit measurements reported here. Squid blood-O2 binding is more sensitive to pH than most other marine animals measured to date. Therefore, the lack of effect in squids suggests that ocean acidification is unlikely to have a limiting effect on blood-O2 supply in most marine animals. The pelagic octopod, Japetella diaphana, is known to inhabit meso- and bathypelagic depths worldwide. Across its range, individuals encounter oxygen levels ranging from nearly air-saturated to nearly anoxic. In Chapter 4, we assessed the physiological adaptations of individuals from the eastern tropical Pacific (ETP) where oxygen is extremely low. Ship-board measurements of metabolic rate and hypoxia tolerance were conducted and a metabolic index was constructed to model suitable habitat for aerobic metabolism. I found that animals from the ETP had a higher metabolic rate than animals from more oxygen-rich habitats. Despite their higher oxygen demand, they maintained better hypoxia tolerance than conspecifics from oxygen-rich Hawaiian waters. Furthermore, I found that hypoxia tolerance in Japetella has a reverse temperature dependence from most marine ectotherms, a characteristic that uniquely suits the physical characteristics of its oxygen-poor environment. Even with their high tolerance to hypoxia, the OMZ core likely has insufficient oxygen supply to meet the basal oxygen demand of Japetella. Despite the limited aerobic habitat in this region, species abundance was comparable to more oxygenated ocean regions, suggesting that physiological or behavioral plasticity such as altered hypoxia tolerance or hypoxic avoidance in this globally-distributed species is sufficient to maintain species fitness in this extreme environment. These findings contribute towards our understanding of the impacts of climate change on cephalopod physiology and biogeography. The study of environmental physiology provides a mechanistic basis for the understanding and prediction of ecological responses to climate change.

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47

Lewis, Ricky W. "TOXICITY OF ENGINEERED NANOMATERIALS TO PLANT GROWTH PROMOTING RHIZOBACTERIA." UKnowledge, 2016. http://uknowledge.uky.edu/pss_etds/77.

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Engineered nanomaterials (ENMs) have become ubiquitous in consumer products and industrial applications, and consequently the environment. Much of the environmentally released ENMs are expected to enter terrestrial ecosystems via land application of nano-enriched biosolids to agricultural fields. Among the organisms most likely to encounter nano-enriched biosolids are the key soil bacteria known as plant growth promoting rhizobacteria (PGPR). I reviewed what is known concerning the toxicological effects of ENMs to PGPR and observed the need for high-throughput methods to evaluate lethal and sublethal toxic responses of aerobic microbes. I addressed this issue by developing high-throughput microplate assays which allowed me to normalize oxygen consumption responses to viable cell estimates. Oxygen consumption is a crucial step in cellular respiration which may be examined relatively easily along with viability and may provide insight into the metabolic/physiological response of bacteria to toxic substances. Because many of the most toxic nanomaterials (i.e. metal containing materials) exhibit some level of ionic dissolution, I first developed my methods by examining metal ion responses in the PGPR, Bacillus amyloliquefaciens GB03. I found this bacterium exhibits differential oxygen consumption responses to Ag+, Zn2+, and Ni2+. Exposure to Ag+ elicited pronounced increases in O2 consumption, particularly when few viable cells were observed. Also, while Ni2+ and Zn2+ are generally thought to induce similar toxic responses, I found O2 consumption per viable cell was much more variable during Ni2+ exposure and that Zn2+ induced increased O2 utilization to a lesser extent than Ag+. Additionally, I showed my method is useful for probing toxicity of traditional antibiotics by observing large increases in O2 utilization in response to streptomycin, which was used as a positive control due to its known effects on bacterial respiration. After showing the utility of my method for examining metal ion responses in a single species of PGPR, I investigated the toxicity of silver ENMs (AgENMs) and ions to three PGPR, B. amyloliquefaciens GB03, Sinorhizobium meliloti 2011, and Pseudomonas putida UW4. The ENM exposures consisted of untransformed, polyvinylpyrrolidone coated silver ENMs (PVP-AgENMs) and 100% sulfidized silver ENMs (sAgENMs), which are representative of environmentally transformed AgENMs. I observed species specific O2 consumption responses to silver ions and PVP-AgENMs. Specifically, P. putida exhibited increased O2 consumption across the observed range of viable cells, while B. amyloliquefaciens exhibited responses similar to those found in my first study. Additionally, S. meliloti exhibited more complex responses to Ag+ and PVP-AgENMs, with decreased O2 consumption when cell viability was ~50-75% of no metal controls and increased O2 consumption when cell viability was <50%. I also found the abiotically dissolved fraction of the PVP-AgENMs was likely responsible for most of the toxic response, while abiotic dissolution did not explain the toxicity of sAgENMs. My work has yielded a straightforward, cost-effective, and high-throughput method of evaluating viability and oxygen consumption in aerobic bacteria. I have used this method to test a broad range of toxic substances, including, metal ions, antibiotics, and untransformed and transformed ENMs. I observed species specific toxic responses to Ag+, PVP-AgENMs, and sAgENMs in PGPR. These results not only show the clear utility of the methodology, but also that it will be crucial to continue examining the responses of specific bacterial strains even as nanotoxicology, as a field, must move toward more complex and environmentally relevant systems.

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Azzolini, Marisa. "Fisiologia pós-colheita de goiabas 'Pedro Sato': estádios de maturação e padrão respiratório." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/11/11144/tde-25022003-140356/.

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A goiaba apresenta elevado grau de perecibilidade necessitando de um manejo pós-colheita eficiente capaz de reduzir os processos de senescência. Para tanto, o conhecimento do padrão respiratório e dos processos envolvidos no amadurecimento é fundamental. O presente trabalho foi realizado com os objetivos de determinar os índices de maturação, a influência dos estádios de maturação na qualidade pós-colheita e o padrão respiratório de goiabas 'Pedro Sato' e avaliar as respostas dos frutos à aplicação do etileno exógeno e ao bloqueador da ação de etileno 1-MCP (1-metilciclopropeno). Na primeira fase determinaram-se os índices de maturação e a influência de três estádios de maturação na qualidade pós-colheita dos frutos. Os frutos foram selecionados em três estádios de maturação segundo a cor da casca: Estádio 1: cor da casca verde-escura; Estádio 2: cor da casca verde-clara; Estádio 3: cor da casca verde-amarela. Os frutos foram armazenados em câmara com temperatura controlada de 23 + 1 o C e 85 + 5 %UR e analisados quanto às mudanças físico-químicas e qualidade sensorial. Na segunda fase do trabalho foi determinado o padrão respiratório dos frutos analisando-se a atividade respiratória, a produção de etileno e as mudanças físico-químicas após a colheita. Analisou-se também a resposta dos frutos à aplicação de etileno (1000ml.l -1 ) e de 1- metilciclopropeno (300nl.l -1 ) também foi avaliada. A cor da casca e a firmeza da polpa foram considerados os melhores índices de maturação. As variáveis físico-químicas apresentaram pouca variação entre os estádios de maturação durante o amadurecimento Porém, foram observadas diferenças significativas em relação à análise sensorial, sendo as melhores notas atribuídas ao estádio 3. Na segunda fase observou-se aumento da atividade respiratória e da produção de etileno independente do estádio de maturação, determinando o padrão climatérico de amadurecimento. Verificou-se que a máxima atividade respiratória e a produção de etileno ocorrem após o completo amadurecimento. Os frutos não responderam a aplicação de etileno exógeno, não apresentando diferenças no amadurecimento em relação aos frutos do tratamento controle. Entretanto, o 1-MCP retardou sensivelmente o processo de amadurecimento dos frutos.
The guava presents high perecibilidade degree needing a handling efficient postharvest capable to reduce the senescence processes. Therefore, it is essential to the knowledge of the respiratory pattern and of the processes involved in the ripening. The present work was accomplished with the objectives of determining the maturation indexes, the influence of the maturation stage in the quality postharvest and the respiratoy pattern of guavas 'Pedro Sato' as well as evaluating the fruit response to the application of the exogenous ethylene and to blocking the action of ethylene 1-MCP (1-metylcyclopropene). In the first phase it was determined the maturation indexes and the influence of three maturation stage in the quality postharvet of fruit. The guavas were selected in three maturation stages according to the color of the peel: Stage 1: dark green peel; Stage 2: light green peel; Stage 3: yellowish green peel. The fruit was stored in a chamber with controlled temperature of 23 + 1 o C and 85 + 5 % RH and analyzed for physicochemical changes and sensorial quality. In the second phase of the work the respiratory pattern of the fruit through the respiratory activity, the ethylene production, and the changes physicochemichal after harvesting. The fruit response to the aplication of exogenous ethylene (1000ml.l -1 ) and of 1-methylcyclopropene (300nl. l -1 ) was also evaluated. The color of the peel and the firmness of the pulp were considered the best maturation indexes. The physicochemical variables presented little variation among the maturation stages during the ripening. However, significantive differences were observed concerning the sensorial analysis, being the best grades granted to stage 3 fruit. In the second phase the fruit presented increse in respiratory activity in production of ethylene independent at the maturation stage, determining the climacteric standard. The maximum respiratory activity and the ethylene production were verified after complete ripening. The guavas did not to responses the application of exogenous ethylene, showing no ripening difference respond in the ripening in relation to the guavas in the control treatment. However, the 1-MCP has sensibly retarded the ripening process in guavas.

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Bron, Ilana Urbano. "Amadurecimento do mamão 'Golden': ponto de colheita, bloqueio da ação do etileno e armazenamento refrigerado." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11136/tde-07072006-161639/.

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Abstract:

O presente trabalho objetivou estudar como o ponto de colheita, o bloqueio da ação do etileno e o armazenamento refrigerado interferem no amadurecimento e na qualidade do mamão Golden. No primeiro experimento, foram colhidos mamões Golden em 4 estádios de maturação (Estádio 0: totalmente verde; Estádio 1: até 15% da casca amarela; Estádio 2: 16-25% da casca amarela; Estádio 3: 26-50% da casca amarela) e analisados, durante o amadurecimento a 23ºC, quanto às características físicas e químicas (cor da casca, firmeza da polpa, sólidos solúveis, acidez titulável e ácido ascórbico), fisiológicas (respiração e produção de etileno) e sensoriais (sabor, odor, firmeza e aparência). A partir do 2º dia de armazenamento a 23ºC, os frutos apresentaram respiração constante ao redor de 31 mL CO2 kg-1 h-1 para os estádios 0, 1 e 2 e de 37 mL CO2 kg-1 h-1 para o estádio 3. Não foi observado típico comportamento climatérico para nenhum dos estádios. Somente frutos colhidos nos estádios 0 e 1 apresentaram pico na produção de etileno de 2,1 µL C2H4 kg-1 h-1 aos 7 dias e 1,3 µL C2H4 kg-1 h-1 aos 6 dias de armazenamento a 23ºC, respectivamente. Frutos colhidos nos estádios 2 e 3 tiveram notas superiores na avaliação sensorial, principalmente quanto ao sabor e aparência. Frutos de todos os estádios de maturação receberam notas iguais ou superiores a regular. A colheita em diferentes estádios de maturação alterou a fisiologia pós-colheita dos frutos, sendo que quando efetuada em estádios menos avançados, diminuiu a qualidade do fruto, mas não impossibilitou seu consumo. No segundo experimento foram utilizados mamões colhidos no estádio 1 de maturação. Metade dos frutos tratados e não tratados com 100 nL L-1 de 1-metilciclopropeno (1-MCP) foi mantida a 23ºC, sendo que a outra metade permaneceu por 20 dias a 11ºC, antes da transferência para 23ºC. Durante o amadurecimento, os frutos foram analisados quanto às mesmas características físicas, químicas e fisiológicas realizadas no primeiro experimento, além da atividade da enzima pectinametilesterase (PME). Frutos que receberam aplicação de 1-MCP e não foram refrigerados, tiveram redução na respiração, produção de etileno, desenvolvimento da cor da casca e atividade da PME, mantendo a firmeza alta durante o armazenamento a 23ºC. Mesmo com o aumento gradual da produção do etileno a 23ºC, frutos tratados com 1-MCP mantiveram a firmeza alta, mas, apresentaram perda da coloração verde. O armazenamento refrigerado prejudicou a produção do etileno nos frutos não tratados e tratados com 1-MCP quando os mesmos foram transferidos para 23ºC. Mesmo assim, a firmeza nesses frutos decresceu, sendo essa diminuição sempre menor nos frutos tratados com 1-MCP. Esses resultados nos levam a considerar que o amolecimento da polpa é mais dependente do etileno quando comparado ao desenvolvimento da cor da casca, e que existem processos independentes do etileno responsáveis pela perda de firmeza. A inibição prolongada do etileno, ou a inibição dos sítios receptores nos frutos colhidos em estádio de maturação precoce, reflete em lenta capacidade de recuperação da ação e produção do etileno, fazendo com que o uso de bloqueadores da ação do etileno nesses frutos deva ser feito com cautela.
The present work had as objective the study of how the harvest time, ethylene action blockade and cold storage influence the ripening and the quality of Golden papaya fruit. In the first experiment Golden papayas were harvested at 4 maturity stages (Stage 0: totally green; Stage 1: up to 15% of yellow skin; Stage 2: 16-25% of yellow skin; Stage 3: 26-50% of yellow skin) and analyzed during ripening at 23ºC in relation to physical and chemical (skin color, pulp firmness, soluble solids, titratable acidity and ascorbic acid), physiological (respiration and ethylene production) and sensorial (flavor, odor, firmness and appearance) characteristics. From the 2nd day of storage at 23ºC, fruits presented stable respiratory activity around 31 mL CO2 kg-1 h-1 for stages 0, 1 e 2 and 37 mL CO2 kg-1 h-1 for stage 3. It was not observed typical climacteric behavior in any maturity stage. Only fruits harvested in stage 0 and 1 showed ethylene production peak of 2.1 µL C2H4 kg-1 h-1 at the 7th day and 1.3 µL C2H4 kg-1 h-1 at the 6th day of storage at 23ºC, respectively. Fruits harvested at stages 2 and 3 had superior scores in sensorial evaluation, mainly for flavor and appearance. Sensorial characteristics of fruits from all maturity stages were scored as regular or superior. Harvest at different maturity stages altered the fruit postharvest physiology and when effectuated at early stages reduced the fruit quality but did not make the fruit consume impossible. In the second experiment papayas harvested at maturity stage 1 were evaluated. Half of the fruit treated and non-treated with 100 nL L-1 of 1-methylcyclopropene (1- MCP) were exposed to 23ºC, while the other half was stored at 11ºC for 20 days, prior to transference to 23ºC. During the ripening, fruits were analyzed for the same physical, chemical and physiological characteristics as done in the first experiment, besides the activity of the pectinmethylesterase (PME) enzyme. Fruits that received 1-MCP, and were not refrigerated, presented reduction in respiratory activity, ethylene production, skin color development and PME activity, maintaining high pulp firmness during the storage at 23ºC. Even with gradual increase in ethylene production at 23ºC, fruits treated with 1-MCP maintained high firmness, but presented loss of green skin color. The cold storage harmed the ethylene production in non-treated and 1- MCP-treated fruits when they were transferred to 23ºC. Even so, the firmness in those fruits decreased, being this decrease always lower in 1-MCP treated fruits. The results suggest that pulp softening is more dependent on ethylene when compared to skin color development and that there are processes responsible for firmness loss that are independent on ethylene. It is also possible to assume that prolonged ethylene inhibition or the inhibition of receptor sites in fruits that were harvested at early maturity stages, reflects in slow recovery capacity of ethylene action and production, suggesting that the use of ethylene action blockers in these fruits must be done with caution.

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Ahmad, Bahuri Nor Faizal. "The effects of volitional breathing and carbon dioxide inhalation on human local field potentials." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:a5431969-0a68-4450-9a12-f5a3288d3730.

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Abstract:

Breathing is an automatic process that we hardly pay any attention to in our daily life. As a social species, we interact using body movement, speech and emotion and these actions require modification of the respiratory pattern. While we understood how the respiratory rhythm is generated, we do not have clear evidence on how higher cortical signals modulate the respiratory pattern. The deep cortical structures in the human brain are inaccessible under normal circumstances, and deep brain stimulation electrode recordings offer an opportunity to understand the neurophysiological interactions ofdeeper brain structures. In this thesis, I investigated deep brain stimulation recordings from implanted electrodes in chronic neuropathic pain subjects in the right and left anterior cingulate cortices, the ventral posterior lateral nucleus of the thalamus and periventricular gray region. The objectives of this research were to elucidate the feed-forward mechanisms of volitional breathing, cortical autonomic regulation, and to investigate whether any of the investigated nuclei haveany carbon dioxide-sensitive neurons which may encode respiratory sensation. The results show lateralisation of the cortical autonomic control whereby the left anterior cingulate exhibits increases in beta band activity (30 to 90 Hz) with cognition and vocalisation tasks. Meanwhile, right anterior cingulate activity increases with hyperoxia. Respiration using various carbon dioxide concentrations shows a constant rise in the alpha band (8 to 14 Hz) activity in the PVG which suggests a sensitive, nonspecific neuronal activity related to systemic carbon dioxide levels.

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Dissertations / Theses on the topic 'Respiration physiology'

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