Renal function of fresh water acclimated Glaucous-winged Gulls, Larus qlaucescens, was studied during infusion of hypotonic and hypertonic NaCl. Two experimental protocols were followed. In one, the closed urine collection system (CCS), ureteral urine was collected using catheters glued over ureteral openings of a supine, previously anesthetized gull. In the other, the open urine collection system (OCS), ureteral urine was collected through a funnel placed in the urodeum of a standing, unanesthetized bird. In both protocols, there was continuous saline infusion of hypotonic (hydration) and hypertonic (LOAD) saline at 0.286 ml⋅min⁻¹. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), ml(kg⋅min) ⁻¹, were determined by ¹⁴C-polyethylene glycol (PEG) and ³H-para-aminohippuric acid (PAH) clearances. Plasma vasotocin (PAVT, pg⋅ml⁻¹) was measured. At the end of 4 h hydration with 0.02 M NaCl, urine flow was high but matched infusion rate only in CCS birds (CCS, 0.29 ± 0.05; OCS, 0.17 ± 0.03 ml⋅min⁻¹), GFR (CCS, 5.56 ± 0.85; OCS, 5.36 ± 0.77) and ERPF (CCS, 15.80 ± 1.60; OCS, 14.35 ± 1.65) were high; urine sodium (UNa+) concentration was low (CCS, 15.0 ± 7.3; OCS, 36.4 ± 6.0 mEq⋅1⁻¹), UNa+ excretion was low (CCS, 6.38 ± 4.2; OCS, 5.19 uEq⋅min⁻¹) ; urine/plasma PEG ratio (U/PPEG) was high (CCS, 22.4 ± 4.4, OCS, 39.6 ± 8.5); free water clearance (CH₂O) was positive (CCS, 0.143 ± 0.011; OCS, 0.052 ± 0.019 ml⋅min⁻¹) , and PAVT was low (ccs,14.7 ± 7.4; OCS, 16.1 ± 2.4) in both groups. Immediately following infusion of 5 M NaCl, GFR, ERPF and urine flow increased for about 10 mins. Fifteen minutes later, the GFR of CCS gulls fell to 70% of pre-load values (P < 0.05) and in OCS gulls, GFR and ERPF fell to 64% (P < 0.01) and 61% (P < 0.05). Eighty mins after infusion of 5 M NaCl, the GFR and ERPF of CCS gulls returned to pre-LOAD levels, but remained low in OCS gulls. Twenty-five minutes after salt load, urine flow had fallen to 49% (P < 0.05) and remained low. In OCS gulls, urine flow had fallen to 13% (P < 0.001) after 185 mins. In both CCS and OCS gulls, UNa+ concentration and excretion increased significantly. Sixty minutes after salt load, UNa+ excretion returned to pre-LOAD levels but UNa+ concentration remained high in CCS (111.7 ± 57.5) and OCS (132.8 ± 12.5) gulls. U/PPEG attained 134.3 ± 26.5 in CCS and 181.2 ± 32.4 in OCS gulls. CH₂O fell significantly (P < 0.05) in CCS gulls but remained unchanged in OCS gulls. Mean PAVT increased to 122.5 ± 5.5 in CCS and 96.0 ± 12.6 in OCS gulls. In both CCS and OCS gulls, salt gland secretion was initiated but ceased 60 mins after 5M NaCl infusion, although 60% of the load was retained in the gull. / Science, Faculty of / Zoology, Department of / Graduate

Orientador: Ana Flavia Nogueira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-14T14:27:05Z (GMT). No. of bitstreams: 1 Freitas_FlavioSantos_M.pdf: 1335737 bytes, checksum: 43bb80b2fab0adc9d9092583a0f45e94 (MD5) Previous issue date: 2009 / Resumo: Neste trabalho foram investigados eletrólitos poliméricos baseados em poli(óxido de etileno-co-2-(2-metoxietoxi) etilglicidiléter) - P(EO-EM) com adição do oligômero dibenzoato de etileno-glicol (DIB)/LiI/I2 e poli(óxido de etileno-co-óxido de propileno) - P(EO-PO), com adição do líquido iônico iodeto de 1-metil-3- propilimidazólio (MPII)/I2 (com e sem a presença de LiI), visando a aplicação em células solares de TiO2/corante. Os eletrólitos foram caracterizados por Calorimetria Exploratória Diferencial (DSC), Espectroscopia de Infravermelho com Transformada de Fourier (FTIR), Ressonância Magnética Nuclear de Hidrogênio (H RMN) e Espectroscopia de Impedância Eletroquímica (EIE). Para o sistema P(EO-EM)/DIB, os estudos realizados por DSC e FTIR mostraram alta homogeneidade entre os componentes, com evidências de coordenação de sal no copolímero e no oligômero. Nas medidas de condutividade iônica, verificou-se saturação em ~10 S cm a partir de 10 % de LiI para todas as proporções de PEO-EM/DIB. Como conseqüência, a aplicação de eletrólitos com 20 % de LiI apresentou resultados bem similares, independente da proporção de DIB no sistema, indicando que os processos cinéticos relacionados ao transporte de carga são diferentes dos eletrólitos géis reportados na literatura, não sendo verificada mudança no potencial de circuito aberto (VOC) dos dispositivos. Para o sistema P(EO-PO)/MPII, as análises por DSC, FTIR e H RMN evidenciaram interações entre o oxigênio do copolímero e o hidrogênio do cátion imidazólio, possibilitando aumento na difusão do par I /I3 (estimado em 1,9x 10 cm s para o eletrólito com 70 % de MPII). A maior condutividade iônica foi obtida para o eletrólito com 70 % de MPII (2,4 x 10 S cm), possibilitando a montagem de células solares com eficiência de 5,66 %. Para todos os dispositivos, a presença de íons I3 promoveu aumento nas reações de recombinação, observando-se valores menores para o VOC com o aumento da concentração de MPII nos eletrólitos. Após a adição de LiI, não foram observadas melhores eficiências em comparação aos dispositivos montados sem a adição do sal. Esses resultados indicam que eletrólitos poliméricos baseados na combinação de polímero e líquido iônico consistem em sistemas promissores para aplicação em células solares. / Abstract: New polymer electrolytes based on poly(ethylene oxide-co-2-(2- methoxyethoxy)ethylglycidylether) - P(EO-EM) with addition of the oligomer ethyleneglycol dibenzoate (DIB)/LiI/I2, and poly(ethylene oxide-co-propylene oxide) - P(EO-PO) with addition of the ionic liquid 1-methyl-3-propylimidazolium (MPII)/I2 (with and without LiI) were investigated in this work aiming at the application in dye-sensitized solar cells. The electrolytes were characterized using Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Ressonance (H NMR) and Complex Electrochemical Impedance Spectroscopy (EIS). For the P(EO-EM)/DIB system, the DSC and FTIR measurements revealed a homogeneous mixture, with evidence of coordination of the salt with both the copolymer and the oligomer. The ionic conductivity measurements presented saturation in ~10 S cm for samples containing at least 10 % of LiI, for all P(EO-EM)/DIB concentration ratios. As consequence, the solar cells assembled with electrolytes containing 20 % of LiI presented similar performance, regardless of the DIB concentration, indicating that the kinetic processes related to the charge transport in these systems are different from those usually observed for gel electrolytes (which cause changes in the open circuit potential, VOC, of the devices). For the P(EO-PO)/MPII system, the DSC, FTIR and HNMR measurements revealed the presence of interactions between the oxygen atoms in the copolymer and the hydrogen atoms from the imidazolium cation, which increased the diffusion of the I/I3 redox couple (estimated to be 1,0 x 10 cm s for the electrolyte containing 70 % if MPII). The highest ionic conductivity was observed for the electrolyte containing 70 % of MPII (2,4 x 10 S cm), leading to the assembly of solar cells with 5,66 % of efficiency. In all the devices assembled, the presence of I3 ions leads to an increase of the recombination reactions, thus reducing the VOC values. This effect is more pronounced for higher concentrations of MPII in the electrolyte. After addition of LiI to these systems, no improvements in the device efficiency were observed. These results show that polymer electrolytes based on the mixture of polymer and ionic liquids are very promissing systems for application in solar cells. / Mestrado / Quimica Inorganica / Mestre em Química

>Magister Scientiae - MSc / Polymer electrolyte membrane fuel cells (PEMFCs) among other fuel cells are considered the best candidate for commercialization of portable and transportation applications because of their high energy conversion and low pollutant emission. Recently, there has been significant interest in high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs), due to certain advantages such as simplified system and better tolerance to CO poisoning. Cost, durability and the reliability are delaying the commercialization of PEM fuel cell technology. Above all durability is the most critical issue and it influences the other two issues. The main objective of this work is to study the durability of membrane electrode assemblies (MEAs) for HT-PEMFC. In this study the investigation of commercial MEAs was done by evaluating their performance through polarization studies on a single cell, including using pure hydrogen and hydrogen containing various concentrations of CO as fuel, and to study the performance of the MEAs at various operating temperatures. The durability of the MEAs was evaluated by carrying out long term studies with a fixed load, temperature cycling and open circuit voltage degradation. Among the parameters studied, significant loss in the performance of the MEAs was noted during temperature cycling. The effect of temperature cycling on the performance of the cell showed that the performance decreases with increasing no. of cycles. This could be due to leaching of acid from the cell or loss of electrochemically active surface area caused by Pt particle size growth. For example at 160°C, a performance loss of 3.5% was obtained after the first cycle, but after the fourth cycle a huge loss of 80.8% was obtained. The in-house MEAs with Pt-based binary catalysts as anodes were studied for CO tolerance, performance and durability. A comparison of polarization curves between commercial and in-house MEAs illustrated that commercial MEA gave better performance, obtaining 0.52 A/cm² at 0.5V and temperature of 160°C, with in-house giving 0.39A/cm² using same parameters as commercial. The CO tolerance of both commercial and in-house MEA was found to be similar. In order to increase the CO tolerance of the in-house MEAs, Pt based binary catalysts were employed as anodesand the performance was investigated In-house MEAs with Pt/C and Pt-based binary catalysts were compared and a better performance was observed for Pt/C than Pt-alloy catalysts with Pt-Co/C showing comparable performance. At 0.5 V the performance obtained was 0.39 A/cm2 for Pt/C, and 0.34A/cm²,0.28A/cm²,0.27A/cm² and 0.16A/cm² were obtained for Pt-Co/C, Pt-Fe/C, Pt-Cu/C and Pt-Ni respectively. When the binary catalysts were tested for CO tolerance, Pt-Co showed no significant loss in performance when hydrogen containing CO was used as anode fuel. Scanning electron microscopy (SEM) revealed delamination between the electrodes and membrane of the tested and untested MEA's. Membrane thinning was noted and carbon corrosion was observed from the tested micro-porous layer between the gas diffusion layer (GDL) and catalyst layer (CL).

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22456号 / 工博第4717号 / 新制||工||1737(附属図書館) / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 安部 武志, 教授 作花 哲夫, 教授 阿部 竜 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(エネルギー科学) / 甲第22798号 / エネ博第412号 / 新制||エネ||79(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー応用科学専攻 / (主査)教授 平藤 哲司, 教授 土井 俊哉, 教授 馬渕 守 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

Polyelectrolytes of opposite charge in aqueous solution can undergo a liquid-liquid phase separation known as complex coacervation. Complex coacervation of ampholytic proteins with oppositely charged polyelectrolytes is of increasing interest as it results in a protein rich phase that has potential applications in food science, protein therapeutics, protein purification, and biocatalysis. However, many globular proteins do not phase separate when mixed with an oppositely charged polyelectrolyte, and those that do phase separate do so over narrow concentration, pH, and ionic strength ranges. Much of the work that has been done on complex coacervates looks at polymer-polymer systems. While there have been some initial studies showing that proteins can undergo complex coacervation, the major design factor studied to date has been overall protein charge. The tools of genetic engineering, which allow the precise tuning and placement of charge have not been used to more fully understand the design criteria for protein complex coacervation. In this dissertation, we developed a model protein library based on green fluorescent protein (GFP) to study the impact of protein net charge and charge distribution on protein phase separation with polyelectrolytes. We developed a short, ionic polypeptide sequence (6-18 amino acids) that can drive the liquid-liquid phase separation of globular proteins. We characterize the phase behavior of the protein library with a homopolymer and diblock copolymer of similar chemistry to elucidate how protein design impacts macro- and microphase separation. In these phase characterization studies, differences in the nature of phase separation as well as the salt stability of the protein coacervates with the different polymer species are identified. We finally used this model protein library to study the effects of the protein design and phase separation behavior for coacervate-based applications including intracellular protein delivery, purification, and protein stabilization.

京都大学 / 新制・論文博士 / 博士(工学) / 乙第13408号 / 論工博第4194号 / 新制||工||1762(附属図書館) / (主査)教授 安部 武志, 教授 作花 哲夫, 教授 阿部 竜 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The primary objectives of this research are: (1) use a hierarchical structure to study electrode materials for next-generation lithium-ion batteries (LIBs) and (2) understand the fundamentals and utility of solid polymer electrolytes (SPEs) with the addition of halloysite nanotubes (HNTs) for battery applications. Understanding the fundamental principles of electrode and electrolyte materials allows for the development of high-performance LIBs. The contributions of this dissertation are described below. Encapsulated Si-VACNT Electrodes. Two hurdles prevent Si-based electrodes from mass production. First, bulk Si undergoes volume expansion up to 300%. Second, a solid-electrolyte interphase (SEI) forms between the interface of the electrolyte and electrode, which consumes battery capacity and creates more resistance at the interface. Si volume changes were overcome by depositing silicon on vertically-aligned carbon nanotubes (VACNTs). Encapsulating the entire Si-VACNT electrode surface with carbon was used to mitigate SEI formation. Although SEI formation was reduced by the encapsulation layer, capacity fade was still observed for encapsulated electrodes, indicating that SEI formation was not the primary factor affecting capacity fade. Additionally, the impact of the encapsulation layer on Li transport was examined. Two different transport directions and length scales were relevant””(1) radial transport of Li in/out of each Si-coated nanotube (~40 nm diameter) and (2) Li transport along the length of the nanotubes (~10 µm height). Experimental results indicated that the height of the Si-VACNT electrodes did not limit Li transport, even though that height was orders of magnitude greater than the diameter of the tubes. Simulation and experimental data indicated that time constant for Li diffusion into silicon was slow, even though the diffusion distance was short relative to the tube height. Other factors such as diffusion-induced stress likely had a significant impact on diffusion through the thin silicon layer. Solid Polymer Electrolytes. A thorough understanding of the relationships between physical, transport, and electrochemical properties was studied. HNT addition to polyethylene oxide (PEO) electrolytes not only improved the physical properties, such as reduction of the crystallinity of PEO, but also enhanced transport properties like the salt diffusivity. The processing steps were important for achieving enhanced properties. Moreover, HNTs were found to stabilize the interfacial properties of the SPE films during cycling. Specifically, HNT-containing SPE films were successfully cycled at room temperature, which may have important implications for SPE-based batteries.

The content of this work deals with a theoretical search of sodium-based batteries. The first part of the work contains an introduction to the issue of batteries, contains basic concepts, principles of secondary batteries. In the second part, the basic three divisions of sodium batteries according to the design principles are discussed in more detail. He also deals with the theory of ionic liquids. Their mechanical, thermal and electrical properties and the method used to measure electrolytes are described here. The practical part describes the measurement procedure, displays the recorded measured values and their evaluation.

Through the years, various studies (1-5) have been done regarding the prevalent practice of adding one or more drugs to parenteral fluids. The greater variety of drugs being used intravenously, plus the formulation of newer and more complex parenteral fluids, has led to an increased awareness of potential incompatibilities existing between drug and solution. Recognition of the hazards of such extemporaneous combinations has necessitated the study of drug stability in solution. The objective of this report is to determine compatibility characteristics of admixtures prepared from a series of balance intravenous electrolyte solutions and a group of commonly used therapeutic agents. Visual, spectrophotometric and microbiological assay techniques are to be used to establish the compatibility profiles of these admixtures.