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Effectiveness of short term heat acclimation on intermittent sprint performance with moderately trained females controlling for menstrual cycle phaseGarrett, A.T., Dodd, E., Biddlecombe, V., Gleadall-Siddall, D., Burke, R., Shaw, J., Bray, J., Jones, Huw, Abt, G., Gritt, J. 29 April 2020 (has links)
Yes / Introduction: Investigate the effectiveness of short-term heat acclimation (STHA), over
5-days (permissive dehydration), on an intermittent sprint exercise protocol (HST) with
females. Controlling for menstrual cycle phase.
Materials and Methods: Ten, moderately trained, females (Mean [SD]; age 22.6 [2.7]
y; stature 165.3 [6.2] cm; body mass 61.5 [8.7] kg; VO˙
2 peak 43.9 [8.6] mL·kg−1
·min−1
)
participated. The HST (31.0◦C; 50%RH) was 9 × 5 min (45-min) of intermittent exercise,
based on exercise intensities of female soccer players, using a motorized treadmill and
Wattbike. Participants completed HST1 vs. HST2 as a control (C) trial. Followed by
90 min, STHA (no fluid intake), for five consecutive days in 39.5◦C; 60%RH, using
controlled-hyperthermia (∼rectal temperature [Tre] 38.5◦C). The HST3 occurred within
1 week after STHA. The HST2 vs HST3 trials were in the luteal phase, using self-reported
menstrual questionnaire and plasma 17β-estradiol.
Results: Pre (HST2) vs post (HST3) STHA there was a reduction at 45-min in Tre by
0.20◦C (95%CI −0.30 to −0.10◦C; d = 0.77); Tsk (−0.50; −0.90 to −0.10◦C; d = 0.80);
and Tb (−0.25; −0.35 to −0.15◦C; d = 0.92). Cardiac frequency reduced at 45-min
(−8; −16 to −1 b·min−1
; d = 1.11) and %PV increased (7.0; −0.4 to 14.5%: d = 1.27).
Mean power output increased across all nine maximal sprints by 56W (−26 to 139W;
d = 0.69; n = 9). There was limited difference (P > 0.05) for these measures in HST1
vs HST2 C trial.
Discussion: Short-term heat acclimation (5-days) using controlled-hyperthermia, leads
to physiological adaptation during intermittent exercise in the heat, in moderately trained
females when controlling for menstrual cycle phase.
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Concentration of Osmotic Dehydration Solutions using Membrane Separation ProcessesWarczok, Justyna 02 December 2005 (has links)
El procesado de alimentos conlleva, en mayoría de los casos, la generación de subproductos o residuos que pueden ser reutilizados o revalorizados mediante la utilización de técnicas de separación por membrana. Estas técnicas ofrecen la posibilidad de tratar las soluciones en condiciones de operación muy suaves, y no comportan en mayoría de las ocasiones, una alteración de los componentes a recuperar. Actualmente, las técnicas de separación por membrana, debido a su alta calidad y relativamente bajos costes, se encuentran completamente integradas en la mayoría de procesos productivos que requieren de una etapa de separación. Sin embargo, la investigación en el área de las técnicas de separación por membrana sigue abriendo nuevos campos de aplicación, que surgen con la mejora de las condiciones tecnológicas de los equipos y la posibilidad de obtener nuevas membranas adaptables a necesidades específicas.En concreto, en este proyecto se utilizaron técnicas de separación por membranas para concentrar soluciones de azúcar procedentes de deshidratación osmótica (en adelante OD). El principal objetivo fue estudiar el potencial de varias técnicas de separación, haciendo hincapié en los flujos obtenidos durante la reconcentración y en la calidad de la solución reconcentrada.La deshidratación osmótica es un tratamiento que permite una eliminación parcial del agua en un alimento y/o la incorporación de solutos de una manera controlada, respetando la calidad inicial del producto. El proceso consiste en introducir los alimentos en una solución hipertónica, controlando las condiciones de operación para favorecer, en mayor o menor grado la incorporación de solutos y la deshidratación del alimento. La aplicación de OD puede resultar en la mejora de las propiedades nutricionales y funcionales de los alimentos y en la reducción de la energía requerida para la deshidratación. El principal problema de la aplicación industrial de la OD radica en la gestión de la solución procedente del proceso. La reutilización de esta solución plantea una doble ventaja: primero desde el punto de vista ambiental, ya que se elimina un efluente del proceso que a menudo no puede ser vertido directamente, y segundo el ahorro económico que representa la recuperación de las materias primas que muchas veces contienen solutos de importante valor económico. Los métodos de separación por membrana utilizados para recuperar las soluciones de OD fueron los siguientes: nanofiltración, osmosis directa y destilación osmótica por membranas. La nanofiltración (NF) presenta altos niveles de retención y un menor gasto de energía que la osmosis inversa, y en la industria azucarera se aplica como uno de los pasos en la clarificación y concentración de jarabes. En los procesos de contactores de membranas: osmosis directa (DO) y destilación osmótica por membranas (OMD), a diferencia de los procesos basados en el tamizaje, el flujo depende solamente de la diferencia de potencial osmótico. Las únicas presiones hidráulicas requeridas son las necesarias para bombear la solución de azúcar y la solución osmótica hasta la superficie de la membrana. Estas características hacen que estos procesos presenten como muy prometedores para la reconcentración de soluciones de azúcar de concentraciones elevadas.Los experimentos de filtración se llevaron a cabo utilizando plantas piloto diseñadas y construidas expresamente para el presente proyecto. Durante todos los procesos de separación por membranas, se empleó como solución modelo una solución de sacarosa a diferentes concentraciones (5-60 ºBrix), debido a que las soluciones aplicadas en la deshidratación osmótica de frutas son habitualmente soluciones de azucares (sacarosa, glucosa o jarabes). Durante los experimentos de NF se evaluó el funcionamiento de las membranas planas: Desal5 DK (GE- Osmonics), MPF-34 (Koch Membrane), NFT-50 (DSS) y tubulares: MPT-34 (Koch Membrane) y AFC 80 (PCIMembranes). Además de la solución de azúcar de diferentes concentraciones (5-20 ºBrix), se concentraron zumos de pera y manzana.La reconcentración mediante osmosis directa se realizó utilizando dos modos de operación: off-site e on-site. En el modo off-site, la reconcentración por ósmosis directa se llevó a cabo en una planta de filtración provista de un módulo plano o tubular, dependiendo de la membrana. En el módulo se llevó a cabo la concentración. En el modo on-site, la deshidratación se realizaba conjuntamente con la reconcentración de la solución osmótica. La solución de reconcentración de la osmosis directa en off-site (offsiteDO) fue NaCl, mientras la solución de reconcentración de la osmosis directa on-site (on-site DO) fue una solución de sacarosa más concentrada que la solución osmótica (60 para una solución osmótica de 40 y 68 para una solución de 50 ºBrix). Para garantizar el flujo de agua entre las dos soluciones y altas retenciones de azúcar durante la off-site DO, se utilizaron membranas de NF planas (Desal5-DK y MPF-34) y tubulares (MPT-34 y AFC80). La reconcentración por osmosis directa on-site se levó a cabo empleando una membrana de microfiltración (Durapore, Millipore), ya que la solución de reconcentración (SS) es la misma que la solución osmótica y la alta viscosidad de la SS restringe mucho el flujo de agua si se utiliza una membrana más densa.En la deshidratación por membranas (OMD) se utilizaron membranas hidrófobas (11806, Sartorius) que presentan una retención teórica del 100 %. Se comparó el rendimiento de dos soluciones de reconcentración: NaCl y CaCl2.Con el fin de obtener información referente a la influencia de las propiedades de las membranas sobre el desarrollo del proceso de concentración de las soluciones procedentes de la deshidratación osmótica, se realizó un estudio detallado de las propiedades de las membranas aplicadas mediante AFM, SEM, FTIR, ángulo de contacto y medidas de potencial zeta. Con la finalidad de generar soluciones osmóticas para someterlas a reconcentración, y también para disponer de productos procedentes de deshidratación osmótica con soluciones frescas que pudieran compararse con aquellas procedentes de OD con solución reconcentrada, se deshidrataron diferentes lotes de manzana (Granny Smith) con soluciones de sacarosa de 40, 50 y 60 ºBrix. Estas pruebas permitieron determinar también el tímelo de operación para una máxima pérdida de agua con relativamente poca impregnación de las manzanas. Después de cada experimento se analizaron los siguientes parámetros: concentración de azúcar, pH, absorbancia a 420 nm de las soluciones y humedad de las manzanas.La nanofiltración, aplicada en la primera fase del presente estudio, resultó ser viable solamente para la reconcentración de soluciones de concentraciones hasta 24 ºBrix. El aumento de la temperatura de 25 hasta 35 ºC para las dos membranas tubulares ocasionó un incremento del flujo de permeado, y el mismo efecto tuvo el aumento de presión transmembranaria de 8 a 12 bar.Se comprobó que el factor más importante para la eficacia del proceso es disponer de una membrana que combine altos flujos y retenciones durante el proceso. La deposición de las partículas de sacarosa y/o los zumos se caracterizó mediante SEM y la topología de la capa filtrante de la membrana se identificó usando AFM. La topología de la capa filtrante de las membranas era diferente para cada una de ellas, a pesar de que todas estaban preparadas con el mismo material (poliamida). En las imágenes de los cortes transversales de las membranas realizados con SEM, se observaron los cambios en la estructura de las membranas producidos por la aplicación de presión durante los experimentos y las altas temperaturas empleadas durante su acondicionamiento. Gracias a las imágenes de SEM se pudo verificar también la eficacia del proceso de acondicionamiento de membranas.A diferencia de NF, tanto la ósmosis directa como la destilación osmótica por membrana permiten la reconcentración de soluciones concentradas de sacarosa (hasta60 ºBrix). La eficacia de estas dos últimas técnicas se evaluó en unción de los flujos de agua obtenidos.El sistema de ósmosis directa on-site propuesto para la reconcentración de las soluciones de OD permitió reutilizar las soluciones osmóticas como mínimo cuatro veces. Para la solución osmótica de 40 ºBrix la humedad de las manzanas fue similar utilizando solución fresca o reconcentrada. En cambio, una solución osmótica de 50 ºBrix, la pérdida de agua de las manzanas fue mayor cuando la deshidratación osmótica se llevó a cabo con reconcentración on-site de la solución osmótica. Los análisis de concentración de azúcar de las soluciones osmóticas y de la solución de reconcentración indican que la membrana elegida para los experimentos facilita el transporte óptimo de solutos y agua entre las dos soluciones. Además, el sistema de reconcentración por membrana propuesto es muy sencillo y de bajo coste porque no requiere presurización.La osmosis directa en off-site proporcionó flujos mucho mayores que los obtenidos con el sistema on-site (1.3 kg/m2h para la solución osmótica de 50 ºBrix respecto a 0.0023 kg/m2h durante on-site DO para la misma solución). Sin embargo, el transporte de solutos de la solución de reconcentración hacía la solución osmótica puede ser considerado un obstáculo para su aplicación a escala industrial.Los flujos de agua más elevados fueron obtenidos utilizando la OMD (2.01 kg/m2h para la solución osmótica de 50 ºBrix y con CaCl2 con la solución de reconcentración). Otra gran ventaja de este proceso es la retención de solutos que proporciona, hecho confirmado por los análisis realizados.El estudio sobre el transporte durante los procesos de contactores de membranas indicó que la viscosidad es la propiedad limitante para la solución osmótica y la actividad de agua/alta presión osmótica como la propiedad más importante a la hora de elegir una solución de reconcentración. Para todos los procesos de separación aplicados, el aumento de la concentración de azúcar de la solución osmótica comporta una disminución notable del flujo de agua.El desarrollo de un posible proceso de deshidratación osmótica con una etapa de reconcentración de la solución osmótica mediante procesos con contactores de membrana ha permitido calcular el área requerida para realizar la reconcentración: 3.6,9.7, 1608 m2 para OMD, off-site DO e on-site DO, respectivamente.Las conclusiones del trabajo confirman la posibilidad de utilizar procesos por membrana para realizar la reconcentración de soluciones osmóticas. No obstante se ha constatado que técnicas más tradicionales basadas en diferencias de presión (NF) no son
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Acidic-basic properties of catalysts for conversion of biomassStosic, Dusan 18 December 2012 (has links) (PDF)
Glycerol and fructose are molecules that are readily available in substantial quantities fromthe biomass. In this work dehydration routes for valorization of these compounds wereinvestigated. Therefore, zirconia and titania based catalysts, and calcium phosphate materialswere prepared and evaluated in the glycerol dehydration in gas phase. Niobia-ceria mixedoxides and mesoporous Nb2O5-MeO2 (M = Ce, Zr, Ti) mixed oxides were prepared andtested in fructose dehydration reaction in aqueous phase. The surface acid-base properties ofthe studied catalysts were correlated to their catalytic performance.
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Screening and identification of dehydration in older people admitted to a geriatric and rehabilitation unitVivanti, Angela Patricia January 2007 (has links)
The diagnosis of dehydration in the older person admitted to hospital has been associated with increased morbidity and mortality. In spite of the high US hospital mortality and morbidity rates associated with dehydration (although presumably not the only contributing factor), no standardised or validated approach to assess or easily screen for dehydration in the hospital setting is reported in the international literature. Therefore, a series of studies was undertaken to assess the extent of this, and to identify other gaps in the current literature. The first study estimated the dehydration prevalence amongst older people upon admission to geriatric and rehabilitation unit in the Australian setting to estimate the morbidity burden in the Australian context. The second study assessed the application of dilution and bio-electrical impedance (BIA) techniques as alternative means to assess dehydration in the clinical setting. The third study undertook to validate against total body water the parameters required to confirm dehydration and to identify those that contribute little to discrimination. The final study integrated the information from the first two studies to identify a clinically practical, sensitive and specific screen suitable for the identification of those at risk of dehydration in a geriatric and rehabilitation unit. Older people aged 60 years or over admitted to the Geriatric and Rehabilitation Unit (GARU) of a tertiary teaching hospital in Brisbane. Australia, were eligible for participation in the study. Individuals were excluded if: involuntarily admitted, informed consent was not obtained, younger than 60 years or fitted with a pacemaker (due to contraindication with the use of BIA). Of 82 GARU participants approached, 43 fulfilled the inclusion criteria and consented, 21 declined and 18 were ineligible. Thirty-five (35) of the 43 were able to be involved in the assessment of prevalence. The studies in this thesis provide original insights into dehydration including prevalence, body water contents, useful clinical assessment and screening parameters. Results showed that dehydration prevalence amongst older people is substantially underreported in the Australian geriatric and rehabilitation unit setting (17.1%) when compared to the reported through coding from the medical record (5.3%). The presence of dehydration has frequently been measured in healthy populations by assessing total body water loss through short-term weight change. Gold standard dilution and bio-electrical impedance techniques were used to assess body water as the assessment of dehydration by weight change has practical and ethical limitations in the clinical setting for either research or assessment applications. Gold standard dilution studies and the bio-electrical impedance technique were not confirmed to be either practical or valid alternates to assess dehydration in the clinical setting. Weight and body mass index (BMI) confounded the association between body water and dehydration. Good agreement (78-87%) of global clinical dehydration assessment (clinical assessment) was confirmed between the study's medical officer and the consultants of the Geriatric and Rehabilitation Unit (GARU) and thus become the alternate dependant variable. Although the optimal combination of parameters for clinical dehydration assessment was unable to be elucidated, clinically significant changes upon mild dehydration were more apparent with physical as opposed to biochemical parameters. BMI confounded the association between dehydration and some physical measurements, such as the drop in systolic blood pressure on standing and skin turgor. Of all the clinical assessment and screening variables explored, tongue dryness was validated and represents a practical, sensitive (64%) and specific (62%) dehydration screen suitable for use with all older people in a geriatric and rehabilitation unit setting. Dehydration was established to be more prevalent amongst older Australians admitted to hospital than previously acknowledged or identified by hospitals. The finding identifies dehydration as a significant clinical issue considering the ageing Australian population, limited health resources and the association of dehydration with increased morbidity and mortality. The validation of the simple dehydration screen will contribute to the identification and treatment of dehydration. Although the highest sensitivity and specificity is always desired for screening, it is not always achieved. Moderate sensitivity results in more people being identified at risk by the screen than confirmed to be dehydrated through clinical assessment. Moderate specificity results in the screen's failure to identify those who would be clinically assessed with dehydration. Moderate sensitivity and specificity necessitates the assessment of more people than those with the condition and results in other people with the condition of interest not being identified. Each situation is reduced with increasing levels of sensitivity and specificity. A valid and simple dehydration screen provides future opportunities to confirm improved clinical (prevent adverse events, improve or stabilise disease), cost (reduce intensity of care, hospital stay) and client (death, disability) outcomes as a result of improved identification and timely and appropriate treatment. New insights are provided into individual clinical assessment measures as well as valid and reliable screening. A number of recommendations and future dehydration studies are discussed. The key recommendation for future studies is to discern between intracellular and intravascular volume depletion to enable investigation of an homogenous sample. Further studies are needed to also establish optimal dehydration prevention methods (e.g. awareness and positioning of fluids, beverage carts) and provide evidence that hydration support enhances primary (e.g. morbidity and mortality) and secondary (e.g. cognitive or functional measures, quality of life) health outcomes. Through responsive systems in health delivery, dehydration amongst older hospitalised people can be identified, better managed if present, and avoided with suitable treatment.
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Ajustes cardiorrespiratórios em ratos submetidos a diferentes tipos de desidratações / Cardiorespiratory adjustments in rats submitted to different types of dehydrationFávero, Michele Thaís 06 September 2016 (has links)
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Previous issue date: 2016-09-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Arthropods and vertebrates have a great ability to concentrate urine by the kidney and behaviors
directed the conservation and acquisition of water and salt due to activities controlled by
mechanisms involving hormones and neural circuits. The loss of water or body volume can occur
in the intracellular compartment (intracellular dehydration), the extracellular compartment
(extracellular dehydration) or both (absolute or duble dehydration). Studies from our laboratory
had shown that in unanesthetized animals extracellular dehydration produced by furosemide
injection followed by keeping animals with a sodium deficient diet does not alter the basal
cardiovascular parameters, but change the basal ventilation.Therefore, the objectives of our study
in unanesthetized rats submitted to intracellular dehydration or duble dehydration were: 1) to
characterize the baseline cardiorespiratory responses; 2) evaluate the arterial blood gas
parameters; 3) to evaluate plasma concentrations of sodium, potassium and plasma osmolality; 4)
evaluate the cardiorespiratory responses to the activation of glutamate NMDA receptors in the
NTS before and after pretreatment with glutamate NMDA receptor antagonist (AP5) of rats
submitted to mixed dehydration. Holtzman rats were implanted with cannula in the NTS and
catheter inserted in the abdominal aorta via the femoral artery and femoral vein. The ventilation
(VE) measurement were obtained by whole body plethysmography method. The protocols was
performed in rats euhydrated (before dehydration), dehydrated (following the methodology to
induce dehydration) and/or rehydrated rats (2 h after free access to water and 0.3 M NaCl). The
intracellular dehydration induced by intragastric overload 2 M NaCl (2 mL) produced an increase
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in mean arterial pressure (MAP), without change the heart rate (HR), tidal volume (VT),
respiratory rate (fR) and VE. The duble dehydration (intracellular and extracellular combined)
induced by 24 h of water deprivation, produced an increase in MAP and VT without modifying
the HR, fR and VE. In rehydrated rats PAM and VT returned to baseline. Unilateral injections of
L-glutamate and NMDA glutamatergic receptor agonist into NTS of euhydrated rats produced
pressor responses and bradycardia. After 24 hours of water deprivation these pressor and
bradycardic responses produced by NMDA injection in the NTS were reduced, without changing
the bradycardia produced by L-glutamate injection in the NTS. After rehydration, the pressor
responses to L-glutamate and NMDA receptors in the NTS remained low and bradycardia
produced by NMDA injection in the NTS. Furthermore, the objectives of our study in
anesthetized animals subjected to extracellular dehydration were: 1) to characterize the baseline
cardiorespiratory responses and renal sympathetic nerve activity (RSNA); 2) to evaluate the effect
of peripheral blockade of AT1 receptors angiotensinergic on basal cardiorespiratory responses and
on RSNA; 3) to evaluate the arterial blood gas parameters; 4) to evaluate plasma concentrations of
sodium and potassium. Extracellular dehydration induced by subcutaneous injection of the
diuretic furosemide did not affect the basal MAP and HR, phrenic nerve activity (PNA) and
RSNA. Extracellular dehydration did not affect the pressor response produced by intravenous (iv)
injection of ANG II, decreased ASNR and did not change the HR and PNA. The iv injection of
losartan (AT1 receptor antagonist, 1 mg/kg body weight) induced a decrease in MAP without
changing HR, and RSNA and PNA. The hypotensive response after iv injection of losartan was
greater in dehydrated animals. Extracellular dehydration did not affect the response of RSNA and
PNA after losartan administration. The results suggest that changes in the volume and
composition of body fluids affect the cardiovascular control in animals with intracellular
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dehydration. Furthermore, it affects the cardiorespiratory control in animals with mixed
dehydration and glutamatergic neurotransmission in the NTS. Moreover, in anesthetized animals
with extracellular dehydration showed no changes in baseline cardiorespiratory responses and
RSNA. / Os mamíferos apresentam uma grande capacidade de concentração de urina pelo rim e
comportamentos dirigidos à conservação e aquisição de água e sal, devido a atividades
controladas por mecanismos envolvendo hormônios e circuitos neurais. A perda de água ou de
volume pode ocorrer no compartimento intracelular (desidratação intracelular), do compartimento
extracelular (desidratação extracelular) ou de ambos (desidratação absoluta ou mista). Estudo do
nosso laboratório mostrou em animais não anestesiados que a desidratação extracelular produzida
pela injeção de furosemida seguida da manutenção dos animais com uma dieta deficiente em
sódio não altera os parâmetros cardiovasculares basais, mas altera a ventilação basal. Assim, os
objetivos do nosso estudo em animais não anestesiados submetidos à desidratação intracelular ou
mista foram: 1) caracterizar as respostas cardiorrespiratórias basais; 2) avaliar os parâmetros
gasométricos arteriais; 3) avaliar as concentrações plasmáticas de sódio, potássio e osmolaridade
plasmática; 4) avaliar as respostas cardiorrespiratórias à ativação de receptores glutamatérgicos
NMDA no NTS de ratos submetidos à desidratação mista. Foram utilizados ratos Holtzman com
cânulas implantadas no NTS e com cateteres inseridos na aorta abdominal através da artéria e na
veia femoral. As medidas de ventilação (VE) foram obtidas pelo método de pletismografia de
corpo inteiro. Os protocolos foram realizados em ratos normohidratados (antes da desidratação),
desidratados (após a metodologia para induzir a desidratação) e/ou em ratos repletos (2 h após o
livre acesso a NaCl 0,3 M e água). A desidratação intracelular induzida pela sobrecarga
intragástrica de NaCl 2 M (2 mL), produziu um aumento da pressão arterial média (PAM), sem modificar a frequência cardíaca (FC), o volume corrente (VC), a frequência respiratória (fR) e a
VE. A desidratação mista (intracelular e extracelular combinadas), induzida por 24 h de privação
hídrica, produziu um aumento da PAM e do VC, sem modificar a FC, a fR e a VE. Nos ratos
reidratados a PAM e o VC retornaram aos valores basais. Injeções unilaterais de L-glutamato e do
agonista de receptor glutamatérgico NMDA no NTS de ratos normohidratados produziram
respostas pressoras e bradicardicas. Após 24 h de privação hídrica essas respostas pressoras foram
reduzidas, assim como a bradicardia produzida por injeção de NMDA no NTS e sem alteração na
bradicardia produzida por L-glutamato no NTS. Após a reidratação, as respostas pressoras do Lglutamato
e NMDA no NTS permaneceram reduzidas, bem como a bradicardia produzida pela
injeção de NMDA no NTS. Além disso, os objetivos do nosso estudo em animais anestesiados
submetidos à desidratação extracelular foram: 1) caracterizar as respostas cardiorrespiratórias
basais e a atividade do nervo simpático renal (ANSR); 2) avaliar o efeito do bloqueio periférico
dos receptores angiotensinérgicos AT1 sobre as respostas cardiorrespiratórias basais e sobre a
ANSR; 3) avaliar os parâmetros gasométricos arteriais; 4) avaliar as concentrações plasmáticas de
sódio e potássio. A desidratação extracelular induzida pela injeção subcutânea do diurético
furosemida não alterou a PAM e a FC basais, não alterou a atividade do nervo frênico (ANF) e a
ANSR. A desidratação extracelular não alterou a resposta pressora produzida pela injeção
intravenosa (iv) de ANG II, nem a queda na ASNR e não promoveu alterações na FC e na ANF.
A injeção iv de losartan (antagonista dos receptores AT1, 1 mg/kg de peso corporal) promoveu
queda na PAM sem alterar a FC, a ANSR e a ANF. A resposta hipotensora após a injeção iv de
losartan foi maior nos animais com desidratação extracelular. A desidratação extracelular não
alterou a resposta da ANSR e ANF após o bloqueio com losartan. Os resultados sugerem que
alterações na composição e no volume dos líquidos corporais modificam o controle cardiovascular em animais com desidratação intracelular. Além disso, altera o controle
cardiorrespiratório em animais com desidratação mista, bem como a neurotransmissão
glutamatérgica no NTS. E ainda, em animais anestesiados com desidratação extracelular não
apresentaram alterações cardiorrespiratórias basais e nem na ANSR.
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Ecophysiological and agronomic responses of perennial grass species under water stress / Respostas ecofisiológicas e agronômicas de espécies de gramíneas perenes sob estresse hídricoBeloni, Tatiane 19 October 2015 (has links)
The total annual forage production of tropical grasslands in the Brazilian Central area is expected to increase, however, some studies also predict a higher variability of forage production between and within years. In the future, maintenance of many pastures áreas will probably depend on the use of technology and increased productivity, seeking a competitive advantage concerning other activities, or even on its relocation to marginal áreas where forage grasses will be more suitable to abiotic factors. The water stress, both by flooding and drought, may reduce the production and survival of grasses. The objective was to identify the strategies that some genotypes of Paspalum and Urochloa genus use to cope with the flooding and/or water deficiency in the soil. Two greenhouse experiments were conducted: 1 - morphological and physiological characteristics, survival rate and recovery index in five genotypes of Paspalum sp. (BRS Guará, BGP 289, BGP 293, BGP 402 and BGP 397) and U. brizantha cv. Marandu were evaluated under three water conditions (flooded, drought and control); 2 - dehydration tolerance and dehydration avoidance of three cultivars of Urochoa (\'Marandu\', \'BRS Paiaguás\' and \'Basilisk\') and a cultivar Mediterranean Dactylis glomerata L. cv. Medly. In experiment 1, the genotypes of Paspalum sp., especially BGP 289, BGP 402, BGP 397 and cv. Marandu previously submitted water déficit, presented high tiller survival rates after rehydration. The cv. Marandu and BGP 289 access were not tolerant to flooding, presenting a low tiller survival rate and root recovery index. The BGP 293 access was not resistant to flooding, but it was able to survive periods up to 28 days under water depth. The accesses of Paspalum BRS Guará, BGP 402 and BGP 397 presented resistance mechanisms and survival to flooding, related to a high concentration of chlorophyll in the leaf, leaf biomass, and root recovery and tiller survival after a recovery period under water regular condition. In experiment 2, the distinction of cultivars was in accordance with the resource-use strategy. Cultivars of Urochloa were less tolerant to dehydration than cv. Medly. But the most productive Urochloa cultivars (Marandu and Basilisk) further delayed dehydration due to high investment in the root system, and consequently were less dehydration tolerant, with less survival rates under severe drought. The cv. BRS Paiaguás was less productive under regular irrigation than other Urochloa cultivars, but under drought conditions it is closer to the cv. Medly, being highly dehydration tolerant, and presenting high survival rates under severe drought and dehydration avoidance strategies with roots elongation along the soil profile during the drought period. There are differences in responses to other deficit and flooding between and within the Paspalum and Urochloa genus morphophysiological traits used in this study are relevant for the understanding of the mechanisms and discrimination among genotypes. / A partir de predições de futuros impactos climáticos, é esperado um aumento na produção anual total de forragem tropical, contudo estudos também predizem aumento da variação da produção entre e dentro dos anos. Diante desses cenários, é imprescindível buscar vantagens competitivas e o conhecimento do grau de tolerância a estresse abióticos de gramíneas tropicais. O estresses hídrico, tanto por excesso quanto por deficiência, pode reduzir a produção e a sobrevivência da planta forrageira. Assim, objetivou-se identificar as estratégias que alguns genótipos do gênero Paspalum e Urochloa utilizam para lidar com o encharcamento e/ou com a deficiência hídrica no solo. Foram conduzidos dois experimentos em casa-de-vegetação: 1 - avaliou-se características morfofisiológicas, taxa de sobrevivência e índice de recuperação em cinco genótipos de Paspalum sp. (BRS Guará, BGP 289, BGP 293, BGP 402 e BGP 397) e U. brizantha cv. Marandu sob três condições hídricas (alagado, déficit e controle), em vasos pequenos; 2 - mensurou-se em pequenos vasos a tolerância a desidratação e em longos tubos o atraso a desidratação de três cultivares de Urochoa (\'Marandu\', \'BRS Paiaguás\' e \'Basilisk\') e uma cultivar mediterrânea de Dactylis glomerata L. cv. Medly, submetidos a condições sem limitação hídrica e posteriormente sob seca prolongada. Sob déficit hídrico, os genótipos de Paspalum sp., especialmente o BGP 289, o BGP 402 e o BGP 397, e a cv. Marandu, apresentaram altas taxas de sobrevivência de perfilhos após reidratação. A cv. Marandu e o acesso BGP 289 não são tolerantes ao alagamento, apresentaram baixas taxas de sobrevivência e de recuperação radicular. O acesso BGP 293 não é resistente ao alagamento, porém é capaz de sobreviver a períodos de até 28 dias sob lâmina d\'água. Os acessos de Paspalum BRS Guará, BGP 402 e BGP 397 apresentam mecanismos de resistência e sobrevivência ao alagamento, relacionados à alta concentração de clorofila na folha, de biomassa de folhas, e de recuperação radicular e sobrevivência de perfilhos após período de recuperação sob condição hídrica regular. No experimento 2, a distinção dos cultivares foi de acordo com a estratégia de uso dos recursos. Cultivares de Urochloa são menos tolerantes a desidratação que a cv. Medly. Mas as cultivares de Urochloa mais produtivas (Marandu e Basilisk) atrasaram mais a desidratação, devido ao alto investimento no sistema radicular, e consequentemente foram menos tolerantes a desidratação, com memores taxas de sobrevivência sob seca severa. A cv. BRS Paiaguás é menos produtiva sob irrigação regular em comparação as outras cultivares de Urochloa, mas sob seca aproximou-se mais da cv. Medly, mostrando-se altamente tolerante a desidratação, com altas taxas de sobrevivência sob seca severa, além de apresentar estratégia de atraso a desidratação com o alongamento de raízes ao longo do perfil do solo durante a seca. Existem diferenças entre e dentro de espécies dos gêneros Paspalum e Urochloa em relação as respostas sob duas formas de estresse hídrico. As caraterísticas morfofisiológicas utilizadas neste estudo auxiliaram na compreensão dos mecanismos de resposta ao estresse hídrico e na discriminação dos genótipos.
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Effect of palatability on rehydration in Chinese children exercising in the heat. / 飲品味道對炎熱中運動的華籍男女小童之體液平衡及體温調節之影響 / Effect of palatability on rehydration in Chinese children exercising in the heat. / Yin pin wei dao dui yan re zhong yun dong de hua ji nan nü xiao tong zhi ti ye ping heng ji ti wen diao jie zhi ying xiangJanuary 2003 (has links)
Tang Chi-wing, Wendy = 飲品味道對炎熱中運動的華籍男女小童之體液平衡及體温調節之影響 / 鄧稚穎. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 74-86). / Text in English; abstracts in English and Chinese. / Tang Chi-wing, Wendy = Yin pin wei dao dui yan re zhong yun dong de hua ji nan nü xiao tong zhi ti ye ping heng ji ti wen diao jie zhi ying xiang / Deng Zhiying. / Dedication --- p.i / Acknowledgements --- p.ii / Abstract --- p.iii / Table of Contents --- p.vi / List of Tables --- p.viii / List of Figure --- p.ix / Chapter CHAPTER ONE --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Purpose of the Study --- p.4 / Chapter 1.3 --- Hypotheses --- p.5 / Chapter 1.4 --- Definition of Terms --- p.6 / Chapter 1.5 --- Assumptions --- p.7 / Chapter 1.6 --- Delimitations --- p.7 / Chapter 1.7 --- Limitations --- p.8 / Chapter 1.8 --- Significance of Study --- p.8 / Chapter CHAPTER TWO --- REVIEW OF LITERATURE --- p.9 / Chapter 2.1 --- Water Balance during Exercise --- p.9 / Chapter 2.2 --- Effect of Dehydration on Human Body during Exercise --- p.11 / Chapter 2.3 --- Physiological Responses of Dehydration for Children when Exercising in the Heat --- p.17 / Chapter 2.4 --- Effect of Fluid Ingestion during Exercise --- p.20 / Chapter 2.5 --- Drivers of Fluid Replacement --- p.23 / Chapter CHAPTER THREE --- METHODOLOGY --- p.30 / Chapter 3.1 --- Participants --- p.30 / Chapter 3.2 --- Equipment and Instrumentation --- p.31 / Chapter 3.3 --- Preliminary Measurement --- p.31 / Chapter 3.4 --- Study Design and Procedures --- p.35 / Chapter 3.5 --- Collection and Analysis of Blood Samples --- p.44 / Chapter 3.6 --- Statistical Analysis --- p.44 / Chapter CHAPTER FOUR --- RESULTS --- p.46 / Chapter 4.1 --- Exercise Intensity --- p.46 / Chapter 4.2 --- Body Fluid Balance --- p.50 / Chapter 4.3 --- Thermoregulatory Responses --- p.61 / Chapter 4.4 --- Taste Perception Analysis --- p.62 / Chapter 4.5 --- Summary of the Results --- p.66 / Chapter CHAPTER FIVE --- DISCUSSION --- p.67 / Recommendations and Applications --- p.73 / REFERENCES --- p.74 / APPENDIXES --- p.87
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Studies on Poly(N,N-dimethylaminoethyl methacrylate) Composite Membranes for Gas Separation and PervaporationDu, Runhong January 2008 (has links)
Membrane-based acid gas (e.g., CO2) separation, gas dehydration and humidification, as well as solvent dehydration are important to the energy and process industries. Fixed carrier facilitated transport membranes can enhance the permeation without compromising the selectivity. The development of suitable fixed carrier membranes for CO2 and water permeation, and understanding of the transport mechanism were the main objectives of this thesis.
Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) composite membranes were developed using microporous polysulfone (PSF) or polyacrylonitrile (PAN) substrates. The PDMAEMA layer was crosslinked with p-xylylene dichloride via quaternization reaction. Fourier transform infrared, scanning electron microscopy, adsorption tests, and contact angle measurements were conducted to analyze the chemical and morphological structure of the membrane. It was shown that the polymer could be formed into thin dense layer on the substrates, while the quaternary and tertiary amino groups in the side chains of PDMAEMA offered a high polarity and hydrophilicity.
The solid-liquid interfacial crosslinking of PDMAEMA led to an asymmetric crosslinked network structure, which helped minimize the resistance of the membrane to the mass transport. The interfacially formed membranes were applied to CO2/N2 separation, dehydration of CH4, gas humidification and ethylene glycol dehydration. The membranes showed good permselectivity to CO2 and water. For example, a CO2 permeance of 85 GPU and a CO2/N2 ideal separation factor of 50 were obtained with a PDMAEMA/PSF membrane at 23oC and 0.41 MPa of CO2 feed pressure. At 25oC, the permeance of water vapor through a PDMAEMA/PAN membrane was 5350 GPU and the water vapor/methane selectivity was 4735 when methane was completely saturated with water vapor. On the other hand, the relative humidity of outlet gas was up to 100 % when the membrane was used as a hydrator at 45oC and at a carrier gas flow rate of 1000 sccm. For used for dehydration of ethylene glycol at 30oC, the PDMAEMA/PSF membrane showed a permeation flux of ~1 mol/(m2.h) and a permeate concentration of 99.7 mol% water at 1 mol% water in feed.
This work shows that the quaternary and tertiary amino groups can be used as carriers for CO2 transport through the membrane based on the weak acid-base interaction. In the presence of water, water molecules in the membrane tend to form a water "path" or water "bridge" which also help contribute to the mass transport though the membrane. In addition, CO2 molecules can be hydrated to HCO3-, which reaction can be catalyzed by the amino groups, the hydrated CO2 molecules can transport through the water path as well as the amino groups in the membrane. On the other hand, for processes involving water (either vapor or liquid) permeation, the amino groups in the membrane are also helpful because of the hydrogen bonding effects.
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Studies on Poly(N,N-dimethylaminoethyl methacrylate) Composite Membranes for Gas Separation and PervaporationDu, Runhong January 2008 (has links)
Membrane-based acid gas (e.g., CO2) separation, gas dehydration and humidification, as well as solvent dehydration are important to the energy and process industries. Fixed carrier facilitated transport membranes can enhance the permeation without compromising the selectivity. The development of suitable fixed carrier membranes for CO2 and water permeation, and understanding of the transport mechanism were the main objectives of this thesis.
Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) composite membranes were developed using microporous polysulfone (PSF) or polyacrylonitrile (PAN) substrates. The PDMAEMA layer was crosslinked with p-xylylene dichloride via quaternization reaction. Fourier transform infrared, scanning electron microscopy, adsorption tests, and contact angle measurements were conducted to analyze the chemical and morphological structure of the membrane. It was shown that the polymer could be formed into thin dense layer on the substrates, while the quaternary and tertiary amino groups in the side chains of PDMAEMA offered a high polarity and hydrophilicity.
The solid-liquid interfacial crosslinking of PDMAEMA led to an asymmetric crosslinked network structure, which helped minimize the resistance of the membrane to the mass transport. The interfacially formed membranes were applied to CO2/N2 separation, dehydration of CH4, gas humidification and ethylene glycol dehydration. The membranes showed good permselectivity to CO2 and water. For example, a CO2 permeance of 85 GPU and a CO2/N2 ideal separation factor of 50 were obtained with a PDMAEMA/PSF membrane at 23oC and 0.41 MPa of CO2 feed pressure. At 25oC, the permeance of water vapor through a PDMAEMA/PAN membrane was 5350 GPU and the water vapor/methane selectivity was 4735 when methane was completely saturated with water vapor. On the other hand, the relative humidity of outlet gas was up to 100 % when the membrane was used as a hydrator at 45oC and at a carrier gas flow rate of 1000 sccm. For used for dehydration of ethylene glycol at 30oC, the PDMAEMA/PSF membrane showed a permeation flux of ~1 mol/(m2.h) and a permeate concentration of 99.7 mol% water at 1 mol% water in feed.
This work shows that the quaternary and tertiary amino groups can be used as carriers for CO2 transport through the membrane based on the weak acid-base interaction. In the presence of water, water molecules in the membrane tend to form a water "path" or water "bridge" which also help contribute to the mass transport though the membrane. In addition, CO2 molecules can be hydrated to HCO3-, which reaction can be catalyzed by the amino groups, the hydrated CO2 molecules can transport through the water path as well as the amino groups in the membrane. On the other hand, for processes involving water (either vapor or liquid) permeation, the amino groups in the membrane are also helpful because of the hydrogen bonding effects.
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Participação dos receptores gabaérgicos, serotoninérgicos e adrenérgicos do núcleo do trato solitário na ingestão de água e sódio induzida por diferentes tipos de desidratação / Participation of gabaergic, serotonergic and adrenergic receptors of the nucleus of the solitary tract in the water and sodium intake induced by different types of dehydrationTomeo, Rodrigo Anderson 20 December 2016 (has links)
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Previous issue date: 2016-12-20 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / The nucleus of the solitary tract (NTS), the primary site of peripheral osmoreceptor and cardiovascular afferences, is suggested to receive important inhibitory signals involved in the control of water and sodium intake. However, it is not known which neurotransmitters are involved in the transmission of this information. Central gabaergic, serotonergic and adrenergic mechanisms are involved in the control of sodium and water intake and immunohistochemical studies have shown that these receptors are present in the NTS. Therefore, in the present study, we investigated the effects of muscimol (a GABAA receptor agonist), DOI (a serotonergic 5-HT2A/2C receptor agonist), methysergide (a serotonergic 5-HT1/2 receptor antagonist) and moxonidine (α2 adrenergic/imidazoline receptor agonist) injected into the NTS on water and 0.3 M NaCl intake induced by intragastric load of 2 M NaCl (a cellular dehydration protocol), by intracerebroventricular (icv) angiotensin II (ANG II) or by sodium depletion (furosemide + 24 h diet deficient in sodium, a extracellular dehydration protocol). Holtzman rats (290-310 g, n=3-20) had stainless steel cannulas implanted bilaterally into the NTS and into the lateral ventricle (LV). Bilateral injection of muscimol (0.25 and 0.5 nmol/100 nl), and DOI (2.5 μg/100 nl) reduced water intake induced by intragastric load of 2 M NaCl (2 ml/rat) and water intake induced by icv ANG II (50 ng/100nl) without changing 0.3 M NaCl intake. Bilateral injection of DOI reduced water intake induced by icv ANG II. However, DOI produced no changes in the 0.3 M NaCl and water intake induced by sodium depletion. Injections of methysergide (2 μg/100 nl) produced no changes in the water and 0.3 M NaCl intake induced by intragastric load of 2 M NaCl, icv ANG II or sodium depletion. The pre-treatment with methysergide blocked the effect of DOI on water intake induced by intragastric load of 2 M NaCl. Besides that, bilateral injections of moxonidine (0.5 and 5 nmol/100 nl) produced no changes on water intake induced by intragastric load of 2 M NaCl. The results suggest that gabaergic, serotonergic, but not adrenergic, receptors in the NTS are part of a mechanism involved in the inhibitory control of water intake induced by cellular dehydration. Our results also suggest that serotonergic receptors into the NTS participate in the control of water intake induced by icv injection of ANG II. / O núcleo do trato solitário (NTS), sítio primário das aferências cardiovasculares e dos osmorreceptores periféricos, recebe importantes sinais inibitórios envolvidos no controle da ingestão de água e sódio. Porém, não se sabe quais os neurotransmissores envolvidos na transmissão dessas informações. Mecanismos gabaérgicos, serotoninérgicos e adrenérgicos centrais estão envolvidos no controle da ingestão de água e sódio e estudos de imunohistoquímica mostraram que estes receptores estão presentes no NTS. Portanto, no presente estudo, investigamos os efeitos de muscimol (agonista de receptores gabaérgicos GABAA), DOI (agonista de receptores serotoninérgicos 5-HT2A/2C), metisergida (antagonista de receptores serotoninérgicos 5-HT1/2) e moxonidina (agonista de receptores adrenérgicos/imidazólicos α2) injetados no NTS na ingestão de água e NaCl 0,3 M induzida por sobrecarga intragástrica de NaCl 2 M (um protocolo de desidratação intracelular), por angiotensina II (ANG II) intracerebroventricular (icv) ou por depleção de sódio (furosemida + 24 h com dieta deficiente em sódio, um protocolo de desidratação extracelular). Ratos Holtzman (290-310 g), n=3-20 (por grupo), tiveram cânulas de aço inoxidável implantadas bilateralmente no NTS e no ventrículo lateral (VL). Injeções bilaterais de muscimol (0,25 e 0,5 nmol/100 nl) e DOI (2,5 μg/100 nl) no NTS reduziram a ingestão de água induzida por sobrecarga intragástrica de NaCl 2 M (2 ml/rato) sem alterações na ingestão de NaCl 0,3 M. Injeções bilaterais de DOI no NTS reduziram a ingestão de água induzida por ANG II icv. No entanto, injeções bilaterais de DOI no NTS não alteraram a ingestão de NaCl 0,3 M e água induzida por depleção de sódio. Injeções bilaterais de metisergida (2 μg/100 nl) no NTS não produziram alterações na ingestão de água e de NaCl 0,3 M induzidas por sobrecarga intragástrica de NaCl 2 M, ANG II icv ou depleção de sódio. O pré-tratamento com metisergida bloqueou o efeito de DOI na ingestão de água induzida por sobrecarga intragástrica de NaCl 2 M. Além disso, injeções bilaterais de moxonidina (0,5 e 5 nmol/100 nl) no NTS não alteraram a ingestão de água e de NaCl 0,3 M induzida por sobrecarga intragástrica de NaCl 2 M. Os resultados sugerem que os receptores gabaérgicos e serotoninérgicos, mas não os adrenérgicos do NTS fazem parte de um mecanismo envolvido
no controle inibitório da ingestão de água induzida por desidratação intracelular. Nossos resultados também sugerem que receptores serotoninérgicos do NTS participam do controle da ingestão de água induzida por injeção icv de ANG II.
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