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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The Effect of the Bicarbonate Ion on the Respiration of Excised Roots

Miller, Gene W. 01 May 1954 (has links)
For many years man has been searching for a cure for lime-induced chlorosis. This disease is prevalent throughout the entire western United States and is characterized by a yellowing of the leaves, destruction of the chlorophyll, and eventual death of the plant. It has brought devastation of fruit orchards in Utah, costing fruit producers millions of dollars. Hardly any county in Utah is free from this destructive nutritional disease.
22

Offering sodium bentonite and sodium bicarbonate free-choice to lactating dairy cattle

Wester, Leanna E. 03 December 2002 (has links)
The objective of this experiment was to evaluate the effects of free-choice intake of sodium bentonite and sodium bicarbonate on physiological and production parameters. Eight Jerseys and seventeen Holsteins (four fistulated) were randomly assigned to two groups to equalize stage of lactation, age and production history. Two diets were fed: diet 1 without added sodium bicarbonate and diet 2 with sodium bicarbonate added at 1.2% of dry matter. Each group followed a different diet regime: 1) diet 1 with no free-choice (D1-NFC), 2) diet 2 with no free-choice (D2-NFC), 3) diet 1 with free-choice (D1-WFC), and 4) diet 2 with free-choice (D2-WFC). Free-choice options of sodium bentonite and sodium bicarbonate were offered side by side in a covered feeder to breed groups. Diets were changed every 10 d to provide 8 periods with a repetition of each diet regime. All diets were adjusted to 17% ADF and 17% CP. There were no differences with either breed among diets for blood and fecal observations or milk protein. Urine specific gravity was lower in both breeds when sodium bicarbonate was force-fed. Holsteins force-fed sodium bicarbonate had greater intake and milk production than Holsteins not force-fed. In Jerseys, milk urea nitrogen (MUN) decreased when sodium bicarbonate was added to the TMR. During periods in which cows were allowed free-choice access to sodium bentonite and sodium bicarbonate, Jerseys had higher urine pH, fat-corrected milk, MUN, and dry matter intake (DMI), and Holsteins had higher milk fat percentages and fecal pH. / Master of Science
23

The effects of sodium bicarbonate (NaHCO3) on whole body and isolated skeletal muscle performance

Higgins, M. January 2013 (has links)
This thesis examined four key areas considered to contribute to why the efficacy of sodium bicarbonate (NaHCO3) as an ergogenic aid remains equivocal. Firstly, familiarisation to and test re-test reliability of continuous constant load cycling to exhaustion (TLIM) at 110% peak power output (WPEAK) were investigated. Results indicated two trials are required before participants become fully familiarised and reliable data are obtained and that daily biological variation was 6 ± 11% (16 ± 28 s). The primary aim of study two was to determine the most appropriate exercise intensity for future studies in this thesis. A secondary aim was to elucidate why certain participants appear to respond to NaHCO3 ingestion and others do not (Price and Simons 2010, Saunders et al. 2011). Therefore, we evaluated cycling TLIM at 100%, 110% and 120% WPEAK in the same participants. NaHCO3 ingestion increased TLIM by 17% compared to placebo (PLA) at 100% WPEAK. This was due, at least in part, to attenuated localised ratings of perceived exertion (RPEL). No difference in group level data was observed between treatments at 110% WPEAK or 120% WPEAK although there was marked inter and intra individual variance. Thirdly, in order to evaluate the efficacy of NaHCO3 at a tissue level we examined the effects of NaHCO3 on dynamic isolated muscle performance undergoing cyclical length changes. Acute power output (PO) was on average 7.0% greater for NaHCO3 treated extensor digitorum longus (EDL) muscles and 3.6% greater for NaHCO3 treated soleus (SOL) muscles compared to control (CON). Increases in PO were due to greater force production throughout shortening. Treatment of EDL and SOL did not alter the pattern of fatigue at a group level although similar to study 2 there was marked inter individual variation. Finally, to determine the effects of training status we evaluated the effects of 6 weeks high-intensity cycling training on the efficacy of NaHCO3. Overall, pre-training TLIM was 10% greater with NaHCO3 compared to PLA with a benefit to harm odds ratio of 571. Overall, post-training TLIM was 6% greater with NaHCO3 compared to PLA with a benefit to harm odds ratio of 17. Similar to studies 2 and 3 individual variation was observed. Based on daily biological variation for TLIM of 6% (as determined in study 1) and a recommended benefit to harm odds ratio threshold of > 66, NaHCO3 improved TLIM before training only. We concluded that 6 weeks high-intensity cycling training reduces the effectiveness of NaHCO3 in previously non-cycling trained males. The change in efficacy is likely due to, at least in part, training induced changes in intracellular buffering capacity. In summary, NaHCO3 is an effective ergogenic aid for TLIM cycling at 100% WPEAK in non-cycling trained males. This is due, at least in part, to attenuated localised ratings of perceived exertion (RPEL). In contrast, 6-weeks high-intensity cycling training reduces the efficacy of NaHCO3 for TLIM cycling at 100% WPEAK in previously non-cycling trained males. The change in efficacy is likely due to, at least in part, training induced changes in intracellular buffering capacity. At a skeletal muscle level, NaHCO3 increases acute PO in both predominantly fast (EDL) and predominantly slow (SOL) twitch muscle fibres, due to greater force production throughout shortening.
24

Equilibre acide-base lors de l'hémodiafiltration en ligne : modélisation, analyses in vitro et clinique des transferts de bicarbonate

Morel, H. 01 December 2009 (has links) (PDF)
L'hémodiafiltration (HDF) est une technique de dialyse qui est proposée comme alternative à l'hémodialyse (HD) classique pour les patients souffrant d'insuffisance rénale terminale (IRT). L'HDF est de plus en plus utilisée car elle permet une meilleure élimination des molécules de haut poids moléculaire et une meilleure stabilité cardiovasculaire. Toutefois, l'influence de cette technique sur l'équilibre acide-base des patients en HDF est peu discutée dans la littérature. Dans ce travail, les effets des conditions opératoires (débits, pressions, concentration en bicarbonate (HCO3-) du dialysat) sur l'équilibre acide-base (pH, pO2, pCO2 et concentration plasmatique en HCO3-) ont été étudiés. Cette étude est basée sur la réalisation d'essais in vitro et in vivo qui ont permis de comparer l'équilibre acide-base en modes HD et HDF postdilution. Dans le cas des essais in vitro, une étude paramétrique utilisant du sang bovin a été menée. Elle a permis de valider un modèle représentant les variations de la concentration plasmatique du HCO3- au cours d'une séance de dialyse. Puis une étude clinique préliminaire a été effectuée au CHU d'Amiens : 6 patients ont été suivis pour un total de 23 séances de dialyse. Les mêmes tendances entre les essais in vitro et in vivo ont été observées pour la variation plasmatique de HCO3- et la dialysance du HCO3- qui décroît au cours du temps (de 110 mL/min à 40 mL/min au bout d'une heure). Par contre, dû à l'absence de respiration, les variations de pO2 et pCO2 sont différentes dans les essais in vitro. Quant à la comparaison HD/HDF, d'autres essais in vivo restent encore à réaliser pour obtenir un résultat significatif sur le plan statistique.
25

Cristallisation du bicarbonate de sodium : étude pratique et théorique / Sodium bicarbonate crystallization : theoretical and practical study

Gérard, Antoine 18 June 2014 (has links)
Récemment, il y a une demande accrue pour des cristaux de bicarbonate de sodium de propriétés d'usage spécifiques. Dans l'étude présentée, la réaction de cristallisation du bicarbonate de sodium est abordée et s'effectue dans un milieu triphasique dans lequel interviennent de nombreux phénomènes tels que le transfert de matière, la nucléation et la croissance cristalline. L'objectif de ce travail est d'étudier l'impact des paramètres opératoires, des additifs et de la technologie du réacteur sur la cristallisation du bicarbonate de sodium afin d'obtenir des cristaux avec une taille importante et une masse volumique apparente non tassée élevée. Les essais réalisés dans un réacteur ouvert de type MSMPR (Mixed Suspension Mixed Product Removal) ont permis d'optimiser les conditions opératoires du procédé et ont montré que l'ajout de calcium par le biais d'une solution de chlorure de calcium dans le milieu réactionnel améliore sensiblement la morphologie des cristaux, réduit la vitesse de nucléation tout en influençant légèrement la vitesse de croissance cristalline. Lorsque du polystyrène sulfonate de sodium (NaPSS) est ajouté au chlorure de calcium, sont obtenus des cristaux encore plus compacts avec des surfaces plus lisses et des arêtes marquées. A contrario, l'utilisation d'additifs chelatant le calcium comme le citrate de calcium dégrade la qualité des cristaux de bicarbonate de sodium et est donc proscrite pour une utilisation industrielle car les étapes de filtration et de séchage sont plus difficiles. Enfin, le passage d'un réacteur MSMPR à un réacteur à lit fluidisé a conduit, dans des conditions opératoires identiques, à une amélioration notable de la qualité du produit fini en produisant des cristaux avec une morphologie relativement sphérique et une taille importante / Recently, there is an increased demand for sodium bicarbonate crystals with specific properties. In the present study, the crystallization reaction of sodium bicarbonate is performed in a three-phase medium in which many phenomena such as mass transfer, nucleation and crystal growth occurred. The objective of this work is to study the impact of operating parameters, additives and reactor technology on the crystallization of sodium bicarbonate in order to obtain crystals with important size and high bulk density. The experiments carried out in a MSMPR (Mixed Suspension Mixed Product Removal) reactor have shown that the addition of calcium through a calcium chloride solution in the reaction mixture improves the crystal morphology, reduces the nucleation rate and weakly influences the crystal growth rate. When a mixture of sodium polystyrene sulfonate (NaPSS) and calcium chloride is used, more compact crystals with smoother surfaces and marked edges are obtained. Conversely, the use of calcium chelating additives such as calcium citrate affects the quality of sodium bicarbonate crystals and thus is prohibited for industrial use because the filtration and drying steps are much more difficult. Finally, the transposition from a MSMPR reactor to a fluidized bed reactor allows, under the same operating conditions, a significant improvement of the solid quality by producing big spheroidal particles
26

Etude expérimentale de la cristallisation du bicarbonate de sodium

Zhu, Yi 13 December 2004 (has links)
Abstract:<p><p>Sodium bicarbonate is one of the major chemical compound used worldwide. We have studied the mechanisms presiding the crystallization of this product in order to identify the kinetic parameters.<p>To be assured of the relevancy of our experimental results, we developed new and accurate measurement techniques to follow the supersaturation and to characterize the crystal morphologies of NaHCO3 like density measurement and images analysis.<p>The systematic study of the mechanisms and the kinetic parameters of the crystallization of NaHCO3 has been conducted by the use of three different types of crystallizers conceived and built at the Department of Industrial Chemistry of ULB :a fluidized bed crystallizer, a classic MSMPR crystallizer and a bubble column. By this choice, we were able to thoroughly investigate the intrinsic phenomena occurring in the crystallization of NaHCO3 from the ideal condition to the conditions close to the industry. <p>A NaHCO3 solution is typically a three components equilibrium, NaHCO3, Na2CO3 and CO2, depending on temperature. Our developed method of density measurement allows to measure continuously the supersaturation, during the crystallization. This method permits to neglect complex side effects due to Na2CO3 or dissolved mineral impurities. Density measurements are quick, sensitive and reliable.<p>We have shown that the growth of sodium bicarbonate is widely controlled by a reaction step at 45°C (< 200 µm). A diffusion step controlled growth occurs however for large crystals (>300-425µm) which consume much less material than the small ones. We have shown that the secondary nucleation of NaHCO3 is principally dominated by the surface nucleation. <p>The shape of the crystals obtained experimentally is in agreement with the theory, and strongly related to the size of the crystals and to the presence of impurities.<p><p>Based on experience of NaHCO3 crystallization without introduction of impurity, we have demonstrated that Ca2+ and Mg2+ suppress crystallization kinetics.<p>In the end, we have taken a brief look at the precipitation of NaHCO3 by gaz-liquid reaction in a bubble column. <p><p>By a comparative and a fundamental approach, our experimental studies lead us to improve our understanding and the operational parameters of the NaHCO3 industrial refining process.<p><p>Key words: Industrial crystallization, Sodium bicarbonate, Density measurement, Fluidized bed, MSMPR, Bubble column, Crystal growth, Nucleation<p><p>Résumé: <p><p>Le bicarbonate de sodium (NaHCO3) est un produit chimique important sur le marché mondial. Nous avons étudier les mécanismes de la cristallisation de ce produit afin d'en déterminer les paramètres cinétiques. <p>Afin de garantir l'analyse la plus objective de ces phénomènes, nous avons développé des techniques de mesures originales pour la connaissance de la sursaturation et pour la caractérisation des cristaux de NaHCO3 par densimétrie et par analyse d’images. <p>L'étude systématique des cinétiques et des mécanismes de cristallisation du NaHCO3 a été réalisée au moyen de trois cristallisoirs de conception différente, développés et construits au laboratoire du Service de Chimie Industrielle de l'ULB: un cristallisoir à lit fluidisé, un cristallisoir à cuve agitée MSMPR et une colonne à bulles. Ce choix nous a permis d'approfondir notre connaissance des phénomènes intrinsèques de la cristallisation du NaHCO3 dans des conditions idéales et des conditions proches des procédés industriels. <p>Une solution de NaHCO3 est un système à l’équilibre à trois composantes, NaHCO3, Na2CO3 et CO2 fonction de la température. La mise au point de la méthode densimétrique a permis la mesure de la sursaturation en NaHCO3 en continu. Cette méthode permet de s’affranchir des complications introduites par la présence de Na2CO3 et des impuretés inorganiques en solution. Les mesures de masse volumique sont rapides, précises et sensibles.<p>Nous avons démontré que la croissance du bicarbonate de sodium est largement dominé par l'étape de réaction à 45°C (< 200 µm). L'étape de diffusion intervient cependant dans la croissance de grands cristaux (>300-425µm) qui ne sont toutefois pas les plus grands consommateurs de matière. Nous avons mis en évidence que le mécanisme de la germination secondaire du NaHCO3 est principalement une germination secondaire vraie.<p>La forme des cristaux obtenus est parfaitement en accord avec la théorie et dépend étroitement de la taille des cristaux mais également de la présence d'impuretés.<p><p>En se basant sur les expériences de cristallisation du NaHCO3 sans introduction d’impuretés, nous avons démontré les effets de ralentissement des cinétiques de cristallisation d'ions tels que Ca2+ et Mg2+ .<p>Nous avons enfin brièvement abordé la précipitation du NaHCO3 par réaction gaz-liquide dans une colonne à bulles. <p><p>Cette approche expérimentale, comparative et fondamentale a permis d'affiner notre compréhension et d’optimiser un procédé industriel de raffinage du bicarbonate de sodium.<p><p>Mots clés: Cristallisation industrielle, Bicarbonate de sodium, Densimétrie, Lit fluidisé, MSMPR, Colonne à bulles, Croissance des cristaux, Germination <p><p> / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished
27

The effect of therapeutic exercise and metabolic acidosis on skeletal muscle metabolism in chronic kidney disease

Clapp, Emma L. January 2010 (has links)
Muscle wasting and increased proteolysis is a major problem in chronic kidney disease (CKD). Exercise is potentially beneficial, but has been under-investigated in pre-dialysis CKD and could theoretically worsen acidosis through exercise-induced lactic acid generation. We therefore investigated effects of 6 months walking exercise with and without additional alkali therapy. 40 patients were recruited (23 male and 17 female, median age 58, range 20-83, mean eGFR±SEM 25.7±1.2ml/min/1.73m2). 20 undertook walking exercise at a Borg Rating of Perceived Exertion Rate (RPE) of 12-14 for at least 30 minutes, 5 times a week. The other 20 continued with normal physical activity (non-exercising controls). In addition to standard oral bicarbonate therapy (STD), 10 patients in each group were randomised to receive additional bicarbonate (XS). Blood and vastus lateralis muscle biopsies were drawn at baseline, one and six months. 18 exercisers (including 8 in XS group) and 14 controls (6 in XS group) completed the 6 month study. Exercise tolerance increased after 1 and 6 months in the exercisers, but not the controls, accompanied by a reduced acute lactate response in the XS, but not the STD exercising group. After 6 months of exercise, 9 intramuscular free amino acids showed striking depletion in the STD, but not XS bicarbonate group. This suggests an inhibition of active amino acid transporters, possibly the SNAT2 transporters that are inhibited by acidosis. Studies with cultured myotubes identified glucocorticoid as a possible mediator of acid s inhibitory effect on SNAT2. The preservation of amino acid concentrations in the XS exercising group was accompanied by strong suppression of ubiquitin E3-ligases MuRF-1 and MAFbx which activate proteolysis through the ubiquitin-proteasome pathway. However, other anabolic indicators (Protein Kinase B activation and suppression of the 14kDa actin fragment) were unaffected in the exercising XS group. Possibly because of this, overall suppression of myofibrillar proteolysis (3-methyl histidine excretion) and increased lean body mass (DEXA) were not observed in the exercising patients. As XS alkali had no effect in non-exercisers, it is concluded that alkali effects in the exercisers arose by countering exercise-induced acidosis. Sulphuric acid produced from the catabolism of sulphur-containing amino acids ingested in the diet is the main contributor to the daily titratable acid load and hence acidosis in CKD. In these patients the amount of sulphate excreted in urine over 24h varied widely between individuals. This directly correlated with 3-methyl histidine excretion suggesting that sulphate excretion may be a better clinical indicator of acidotic patients at long-term risk of cachexia than conventional measures such as venous bicarbonate. Studies with cultured myotubes confirmed that skeletal muscle is a source of sulphuric acid and showed that production of this acid is partly suppressed by L-Glutamine a potential novel way to control acidosis in CKD.
28

An Investigation on Hydration with N-acetylcysteine and Sodium Bicarbonate for Prevention of Contrast-Induced Nephropathy

Rodriguez, Tamara January 2010 (has links)
Class of 2010 Abstract / OBJECTIVES: The purpose of this study was to determine the incidence of contrast induced nephropathy (CIN) for patients receiving a pre-hydration regimen to prevent CIN. METHODS: This was a descriptive retrospective chart review study. Charts were reviewed from Banner Boswell Medical Center and a nephrologist’s office in Sun City, Arizona. RESULTS: There were a total of 12 patients included in the study. The population after completetion of chart reviews consisted of 6 male patients and 6 female patients. The age range of the patients included was 54-90 years old. CIN occurred in zero of the twelve patients. Half of the 12 patients had a decrease in serum creatinine ranging from 0.1- 0.6 mg/dL, 24-48 hours post-diagnostic procedure. CONCLUSIONS: There was no incidence of CIN after the 12 patients received the specific protocol. This study demonstrates the potential for this regimen as a pre-hydration option for individuals undergoing procedures in which radiocontrast is necessitated. A prospective observational study with a larger sample size would be warranted to determine the safety and efficacy of the protocol and increase the validity of the results of this descriptive study.
29

Effect of orally administered sodium bicarbonate on caecal pH

Taylor, Elizabeth Ardelle January 1900 (has links)
Master of Science / Department of Biomedical Sciences / Warren Beard / Reasons for performing study: Caecal acidosis is a central event in the metabolic cascade that occurs following grain overload. Buffering the caecal acidosis by enterally administered sodium bicarbonate may be beneficial to affected horses. Objectives: To determine the effect and duration of enterally administered sodium bicarbonate (NaHCO[subscript]3) on caecal pH in healthy horses. Study design: Prospective controlled study using normal horses with caecal cannulas Methods: 9 horses previously fitted with a caecal cannula. 6 horses received 1.0 g/kg bwt NaHCO[subscript]3 via nasogastric tube and 3 control horses were given 3 L of water via nasogastric tube. Clinical parameters, water consumption, venous blood gases, caecal pH, faecal pH and faecal water content were measured at 6 hour intervals over a 36 hour study period. Results: Horses that received enterally administered NaHCO[subscript]3 had a significantly increased caecal pH that lasted the duration of the study. Treated horses increased their water intake, developed metabolic alcalemia, significantly increased sodium concentrations and significantly decreased potassium concentrations. Conclusions and potential relevance: Enterally administered NaHCO[subscript]3 may be beneficial in buffering the caecal acidosis that occurs following an acute carbohydrate overload
30

Effect of Bicarbonate Ion and Root Aeration on Lime-Induced Chlorosis

Lindsay, Willard L. 01 May 1953 (has links)
Chlorosis in plants has been recognized as a devastating disease for over one-hundred and fifty years. It is easily recognized by a yellowing of the plant foilage and is associated with a reduced chlorophyll synthesis. Chlorosis is found so frequently on calcareous soils that its cause is attributed at least in part to this soil factor. It is therefore referred to as lime-induced chlorosis. This type of chlorosis has become a serious problem, especially in many of the fruit-growing regions of Europe and the Western United States where the soils are calcareous. In Utah the disease is more destructive than any other nutritional disease that affect horticultural crops. The exact cause of lime-induced chlorosis is not known, nor has a satisfactory control been developed as yet. Many conditions found in high-lime soils have been studied with regard to chlorosis, yet the problem is not so simple as it may appear. Green and chlorotic plants are frequently found growing in the same field, and yet a chemical analysis of the two soils fails to indicate a significant difference between them. It is common in chlorotic orchards to see trees where some of the major branches produce chlorotic foilage while the remainder of the tree is healthy and green. The severity of chlorosis varies from tree to tree as well as from season to season. It has been found that the heavier textured soils which are poorly drained are more conductive to chlorosis than are the lighter textured soils. If the soil moisture is held near field capacity, chlorosis is much more severe than if the soil is allowed to approach the wilting point before irrigation. Recent studies have also shown that the bicarbonate ion in solution cultures can induce chlorosis and retard the uptake of iron by plants. Since these factors--high moisture, soil aeration, and bicarbonate ion concentration--are all interrelated, it seems that their relationship to chlorosis should be investigated more thoroughly. Workers in the past have failed to show a consistent correlation between either the oxygen or the carbon dioxide can be measured at the soil-root interface. this is after all the only place in the soil that is of great importance as far as the living plant is concerned. Since the severity of chlorosis increases under poorly aerated conditions on calcareous soils, this hypothesis has been advanced: The respired carbon dioxide is given off at the plant root as carbonic acid which in a calcareous soil reacts with calcium and magnesium carbonate to give an increased bicarbonate ion concentration in the root environment. The resulting increased concentration of bicarbonate may reduce the effective oxygen at the root and thereby disturb the normal respiration and active-ion absorption of the roots or the increased concentration of bicarbonate may affect the roots absorption and plant metabolism in some other manner. The purpose of this investigation was to study the effect of the bicarbonate ion and different aeration mixtures on chlorosis. A preliminary study was made to relate the composition of the soil solution taken from the field with different conditions associated with chlorosis.

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