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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.
231

The effect of electro-activated sodium bicarbonate solutions on chrysanthemums.

Rilly, Jocelyn 21 April 2008 (has links)
The cultivation of chrysanthemums originated in China more than 2000 years ago. Today this flower is regarded as one of the most popular cut flowers in the world. It is, therefore, important to ensure that high quality flowers are produced consistently for the local and export markets. Chrysanthemum morifolium cv. ‘Sunny Reagan’ flowers were grown in a greenhouse sprayed with an electro-activated sodium bicarbonate solution (anolyte) in an attempt to improve productivity and postharvest quality. A non-activated sodium bicarbonate solution was also used to determine the overall effect of sodium bicarbonate on chrysanthemum plants. Sodium bicarbonate acts to enrich the environment of the plant with CO₂ thereby increasing its photosynthetic activity. Anolyte showed a positive preharvest effect on the chrysanthemum plant by increasing the leaf size and overall quality. On the other hand, sodium bicarbonate produced low quality plants with fewer flowers than the control. These plants also exhibited necrotic leaf edges, which is a sign of salt stress. Anolyte-treated plants exhibited no significant increase in postharvest longevity. Anolyte treated plants showed an increase in leaf cell size and density and a decrease in the size of intercellular air spaces, indicating an improved ability for photosynthesis, whereas, treatment with sodium bicarbonate resulted in thinner leaves with a smaller midrib and a less developed vascular system when compared to the control. The chloroplasts in anolyte-treated plants exhibited an increase in starch grains, also an indication of enhanced photosynthesis. Anolyte-treated plants also showed an increase in chlorophyll concentration and an improved CO₂ uptake. It is clear from this study that anolyte stimulated photosynthesis in chrysanthemum plants, thus resulting in longer stems with more and larger flowers and leaves. / Prof. C.S. Whitehead
232

Characterization of Gene Candidates for Vacuolar Sodium Transport from Hordeum Vulgare

Scheu, Arne Hagen August 05 1900 (has links)
Soil salinity is a major abiotic stress for land plants, and multiple mechanisms of salt tolerance have evolved. Tissue tolerance is one of these mechanisms, which involves the sequestration of sodium into the vacuole to retain low cytosolic sodium concentrations. This enables the plant to maintain cellular functions, and ultimately maintain growth and yield. However, the molecular components involved in tissue tolerance remain elusive. Several candidate genes for vacuolar sodium sequestration have recently been identified by proteome analysis of vacuolar membranes purified from the salt-tolerant cereal Hordeum vulgare (barley). In this study, I aimed to characterize these candidates in more detail. I successfully cloned coding sequences for the majority of candidate genes with primers designed based on the barley reference genome sequence. During the course of this study a newer genome sequence with improved annotations was published, to which I also compared my observations. To study the candidate genes, I used the heterologous expression system Saccharomyces cerevisiae (yeast). I used several salt sensitive yeast strains (deficient in intrinsic sodium transporters) to test whether the candidate genes would affect their salt tolerance by mediating the sequestration of sodium into the yeast vacuole. I observed a reduction in growth upon expression for several of the gene candidate under salt-stress conditions. However, confocal microscopy suggests that most gene products are subject to degradation, and did not localize to the vacuolar membrane (tonoplast). Therefore, growth effects cannot be linked to protein function without further evidence. Various potential causes are discussed, including inaccuracies in the genome resource used as reference for primer design and issues inherent to the model system. Finally, I make suggestions on how to proceed to further characterize the candidate genes and hopefully identify novel sodium transporters from barley.
233

Effect of Hand Pinching, Dikegulac-Sodium, and Gibberellic Acid on Chile Pepper (Capsicum Annuum)

Mousa, Abdulfatah 15 December 2012 (has links)
Hand Pinching increased branching and fruit yield. At first harvest dikegulac-sodium at 50 ppm increased fruit yield compared to the control. However, dikegulac sodium at 100 ppm reduced fruit yield initially but had no effect on fruit yield at 2-4th harvests. Digkegulac-sodium, Gibberellic acid, and hand pinching did not affect fruit length at third and fourth harvests. However, first and second harvests dikegulac sodium reduced fruit length whereas GA3 had no effect. None of the treatments affected fruit width. Dikegulac sodium and Hand pinching increased the number of branches after three weeks, but GA3 did not. At 8 weeks after treatment dikegulac solution at 50 ppm and 100 ppm increased branching compared to the control. GA3 at 100 ppm also increased branching. The remaining treatment had no effect. GA3 at 50 ppm increased juice pH comparing to the control. None of treatments affected sugar content at regardless of harvest date.
234

Crystal Structures and Phase Transformations of Sodium Pyrophosphate and Sodium Diarsenate

Leung, Kiang Yiu 05 1900 (has links)
<p> An X-ray study of the various phases of anhydrous sodium pyrophosphate has been carried out. The system began with an ordered structure in orthorhombic space group P212121 and ended with a completely disordered structure in hexagonal space group P63/mmc, All the intermediate phases were partially disordered.</p> <p> The crystal structure of the first two phases of the system were determined while the rest were only partially solved due to the complexity of the disorder involved. A discussion on the symmetry aspects of the phase transformations was given and a model for the disorder of the hexagonal phase was proposed.</p> <p> As an integral part of the study the room-temperature phase of sodium diarsenate was also investigated.</p> / Thesis / Doctor of Philosophy (PhD)
235

Theory of Positron Annihilation in Sodium, Aluminum and Argon.

Salvadori, Antonio 10 1900 (has links)
<p> This work is concerned with the calculation of the angular correlation curves and the lifetime of positrons annihilating in Sodium, Aluminum and Argon. The Carbotte-Kahana theory is developed using orthogonalized plane waves to represent conduction states. The theory is put in a computational form and techniques, which reduce the computational labour to a manageable level are developed for its practical evaluation. Results are obtained for the electron core contribution in Sodium and Aluminum whilst for Sodium a lattice contribution is also attempced. The core theory is applied to Argon with a limiting approximation and results are obtained in a first order perturbation theory approximation. The calculations are compared to experiment with a satisfactory result. </p> / Thesis / Doctor of Philosophy (PhD)
236

Computational studies of the human cardiac sodium channel

Beard, Torien M. 08 December 2023 (has links) (PDF)
Computational methods such as Molecular Dynamics (MD) simulations and Molecular Mechanics generalized Born surface area solvation (MM-GBSA) binding affinity calculations have been utilized to determine the binding modes and final binding affinities of small molecules that are known to interact with the heart sodium channel NaV1.5. Lidocaine, ranolazine, and flecainide are FDA approved arrhythmia drugs that are prescribed to patients in the event of heart disease. Here, we demonstrate the likely binding preferences and modes of action of all molecules with NaV1.5, the stability of the systems, and overall final binding affinities of the small molecules with the protein. To gain insights into the mechanisms of heart disease treatments, the MM-GBSA method was utilized to estimate the binding free energies of each molecule and pose to NaV1.5. The evaluation of the binding of small molecules to NaV1.5 contributes to enhancing our understanding of the underlying processes involved in heart disease treatments. The MM-GBSA approach provides a valuable tool for predicting and analyzing binding affinities, which can aid in the design and optimization of potential therapeutic compounds targeting NaV1.5.
237

Stress corrosion cracking of AISI type stainless steel in 0.01 M sodium sulfate solution and its inhibition by organic and inorganic inhibitors /

Bavarian, Behzad January 1980 (has links)
No description available.
238

Electrochemical studies of Na?CrO?-Na?SO? melts at 1200 K /

Shi, Dingzhu January 1987 (has links)
No description available.
239

Electrochemical studies of metals in fused sodium hydroxide /

Theus, George John January 1972 (has links)
No description available.
240

Ruthenium-Catalyzed Hydrogenation of Aqueous Sodium Bicarbonate

Covino, Duane P. 01 January 1980 (has links) (PDF)
This research report investigated the ruthenium-catalyzed hydrogenation of aqueous sodium bicarbonate. Subjects of the investigation included: the "blank" effect of the 316 stainless steel reactor in the batch mode; the catalytic activities at 150°C for unsupported ruthenium, including ruthenium purge and the metal produced from the in situ reduction of RuCl3·1-3H2O and Ru(IV)O2·H2O; the catalytic activities at 150°C for supported ruthenium including 4.05% w/w ruthenium on alumina, 5.25 and 20.85%w/w ruthenium on molecular sieve SK-41 (ammonium - substituted Y-type), 3.34 and 17.48% w/w ruthenium on SK-41 (prepared by the in situ reduction of the RuCl3·1-3H2O exchange sieve); orders of reaction rate with respect to hydrogen, bicarbonate, and catalyst at 150°C; activity as a function of temperature; and susceptibility to deactivation. The reaction appears to be zero order in both hydrogen and bicarbonate and first order in catalyst at 150°C in the concentration ranges examined; saturation of an assumed limited number of active catalyst sites is assumed to cause the observed zero orders. Conversion was negligible below 150°C, and optimum in the 150°C-200°C range, with product distribution at 150°C heavily favoring methane; e.g. 99% v/v. The stainless steel reactor was found not to catalyze the reaction at 150°C during a two hour reaction. Catalytic activity for unsupported ruthenium paralleled metal surface area (as determined by BET adsorption), while the inverse was found to be true for sieve-supported metal; mass transfer impedance and electronic effects are assumed to be contributing factors. The reaction on alumina-supported ruthenium produced an undesirable white coating, composition as yet undetermined, which strongly adhered to the support and to the reactor walls. Although the reaction investigated is even more exothermic than the Fischer-Tropsch production of methane, and the ruthenium catalyst was also found to be subject to deactivation, the reaction of interest may have an economic advantage over the Fischer-Tropsch synthesis, in that it is less expensive to decompose a bicarbonate species using hydration energy and then hydrogenate directly, then to thermally decompose the ore and hydrogenate the CO2 produced.

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