Thesis (M. Med. Sc.)--University of Hong Kong, 2005.

Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request

Thesis (Ph. D.)--University of Virginia, 2001. / Includes bibliographical references (leaves 223-251). Also available online through Digital Dissertations.

Lysophosphatidylcholine (LPC) is a by product of phospholipid metabolism, that under physiological conditions is maintained at a low level. However, through an enhanced degradation of phospholipids and/or a reduced catabolism, LPC accumulates in the plasma and fluids of patients with disorders underscored by inflammation - such as atherosclerosis, diabetes, ischaemia and epilepsy. Previous studies have demonstrated LPC to possess vasoactive properties, able to both induce and inhibit vasodilation. Furthermore, a variety of proteins are sensitive to LPC, including non-selective cation (NSC) channels and Ca2+-activated K+ (KCa) channels. These channels are intimately associated with the maintenance and regulation of vascular tone. The aim of this study was to elucidate the mechanisms underlying the vascular effect of LPC.Aortic segments were constricted with phenylephrine and exposed to cumulative concentrations of LPC, with an ensuing endothelium-dependent, concentration-dependent vasodilation. Inhibitors of nitric oxide synthase (NOS) and soluble guanylyl cyclase (sGC) abolished LPC-induced responses, implicating nitric oxide (NO) as the mediator. Two cation fluxes were implicated in the dilator activity of LPC - Ca2+ and K+. NSC channel antagonists and reduced extracellular Ca2+ concentration attenuated dilation and reduced the Ca2+ signal activated in isolated rat aortic endothelial cells (RAEC) by LPC, implicating endothelial Ca2+ influx in the response. In addition, LPC also evoked a robust hyperpolarisation of isolated RAEC membrane potential. The K+ channel antagonists TEA+, TRAM-34 and apamin, inhibitors of KCa channels, attenuated both the LPC-induced dilation and RAEC membrane hyperpolarisation, highlighting their potential role in mediating both these processes. HEK293 cells, which lack many of the channels and signalling pathways possessed by other cells, mimicked RAEC in their sensitivity to LPC, generating robust elevations of intracellular Ca2+ when exposed to this lysolipid. Likewise, membrane hyperpolarisations were also observed in HEK293 cells, however, these only occurred when cells expressed recombinant KCa channels. This suggests that KCa channel activation is dependent upon Ca2+ influx, not vice versa. Phospholipase C (PLC) inhibitor U73122, attenuated LPC-induced hyperpolarisation, raising the question as to the possible involvement of G-protein coupled receptors in the bioactivity of LPC. Alternately, LPC might initiate PLC activity, and subsequent NSC channel opening and Ca2+ influx via a perturbation of membrane integrity, like certain local anaesthetics. It is proposed that endothelial NSC-channel activation by LPC initiates endothelial cell signalling, with concomitant activation of Ca2+-sensitive proteins such as NOS, to bring about vasodilation, and KCa channels, which modulate membrane potential and in turn the driving force for Ca2+ entry.

L’origine de ce travail est principalement les effets biologiques potentiels des ondes électromagnétiques de la gamme non ionisante rencontrés dans la littérature et quelques faits observés par des clients de la technologie commercialisée par la société Planet Horizon SA. Les essais de couplage du traitement aux ondes électromagnétiques et les procédés de traitements des eaux usées par boues actives sont réalisés à niveau industriel au sein de la STEP de Penthaz (Suisse) compose de 2 lignes parallèles et sur des pilotes de laboratoire en mode SBR. Le traitement électromagnétique de très basse fréquence (Antennes émettant deux fréquences harmoniques F1 et F2 < 10 kHz) est appliqué via 5 antennes dans le bassin d’aération ou une antenne sans le SBR directement. Dans une autre expérience , des tubes, émettant les mêmes fréquences, sont utilisés pour le recyclage de la liqueur mixte avec toujours une ligne de référence. Au niveau de la STEP, dans le bassin d’aération le traitement électromagnétique a permis une réduction de la quantité de biomasse produite au niveau de l’essai de l’ordre de 42,5% par rapport à ligne témoin. De plus, ce traitement électromagnétique n’affecte pas la qualité de l’eau épurée puisque la quantité de DCO résiduelle est la même à la sortie des deux ligne (REF et EM) et le rendement d’abattement de la matière organique est de l’ordre de 94% pour les deux lignes. Par contre à l’échelle du laboratoire, les résultats obtenus après le couplage du traitement électromagnétique n’ont aucun effet sur la quantité de biomasse produite dans les différents essais avec antenne ou bobine comme étant des émetteurs d’ondes EM. De même, on ne remarque aucun effet significatif sur les rendements de dépollution. La deuxième partie concerne l’application de ces mêmes ondes sur la formation de biofilm microbien. Les champs électromagnétiques visés sont des faibles champs de quelques dizaines de milli-teslas au niveau du générateur (tension de l’ordre de la dizaine de volts et intensité de l’ordre d’un ampère) avec des fréquences comprises entre 0 et 10 kHz; deux ondes de fréquences harmoniques sont imposées simultanément. Le biofilm est quantifié au cours du temps grâce à la mesure de différents paramètres (densité optique, DCO, protéines, ATP, exopolysaccharides). Les résultats expérimentaux démontrent que l’onde électromagnétique limite la formation du biofilm si la continuité hydraulique est assurée entre la bobine électromagnétique et les supports de biofilm ; la quantité de biofilm mesurée est alors deux fois plus faible environ. Cependant, l’effet semble bactériostatique et non bactéricide : l’application de l’onde ne détruit pas le biofilm mais réduit sa formation car dès l’arrêt de l’onde, la vitesse augmente. Des signaux électriques de quelques millivolts et dans le domaine des très basses fréquences ont été détectés seulement dans la cuve en continuité hydraulique avec le générateur d’ondes et située à une distance de 1m environ. Des mesures de champs électromagnétiques dans l’air donnent des intensités de champs très faibles ne pouvant expliquer un effet thermique ou ionisant sur le biofilm. / The first part of this work concerns the coupling of VLF electromagnetic waves treatment and the processes of wastewater treatment by activated sludge in order to reduce excess sludge. Experiments are made at real -scale ( Penthaz , Switzerland),containing two parallel lines and at lab-scale with SBR pilots. The electromagnetic treatment of very low frequency ( antennaemitting harmonic frequencies F1 and F2 <10 kHz) is applied via 5 (2,3x1m) antennas in the aeration basin of the real plant. Other type of antenna (30x 5 cm) was configurated for one of the labscale assays. In the other lab-scale experiment, tubes emitting the same frequency are used for recycling the mixed liquor. With the WWTP, the amount of excess sludge produced in the treated line is reduced by about 42.5%, compared to the control line. In addition, the electromagnetic treatment does not affect the quality of treated water. In this case, outlet COD concentration was similar for the the two lines (REF and EM) and the reduction of or ganic matter yield was about 94% for the two lines. Electromagnetic treatment had no effect on the amount of excess biomass produced in all tests conducted at lab-scale. No significant effect has been noticed regarding depollution yields. The second part aims to better understand the interaction between an electromagnetic wave of very low frequency and biological material and, in particular, the effects on the development of microbial biofilms. Electromagnetic fields are covered weak fields a few milli-Tesla (voltage of the order of tens of volts and intensity of the order of one ampere) with frequencies between 0 and 10 kHz, two waves of harmonic frequencies are transmitted simultaneously. The biofilm was quantified over time by measuring different parameters (optical density, COD, protein, ATP, exopolysaccharides). The experimental results how that the electromagnetic wave limit biofilm formation ( close to 50% of untreated biofilm) if the hydraulic continuity is ensured between the electromagnetic coil. However, the effect appears bacteriostatic and no antibacterial : the application of the wave does not destroy the biofilm but reduced its establishment and upon discontinuation of the wave, the growth increases. Measurements and modeling of electromagnetic fields in the air give intensities of very weak fields that can explain a thermal or ionizing effect on the biofilm.

In freshwater fish, such as the rainbow trout (Oncorhynchus mykiss), higher ion concentrations in the body fluids relative to the dilute surrounding environment lead to diffusive ion loss that is countered by active ion uptake. Active ion uptake is achieved via specialised cells in the gill epithelium known as ionocytes, with the species studied to date exhibiting multiple ionocyte subtypes with specific complements of ion transport proteins. To better understand the functions and responses of each ionocyte subtype, methods are needed to isolate specific ionocyte subtypes. This thesis developed a method to use fluorescence-activated cell sorting (FACS) to isolate the peanut lectin agglutinin-positive (PNA+) ionocyte subtype of the trout gill, which is posited to be a base-secreting cell that takes up Cl- ions. A suspension of gill cells dissociated using ethylenediaminetetraacetic acid (EDTA) was labelled with biotinylated PNA that was detected using streptavidin conjugated to a fluorophore, and subjected to FACS to yield a population of PNA+ ionocytes of high viability and purity. To validate the utility of the approach, it was used in a proof-of-principle experiment to evaluate transcript abundance of cytosolic carbonic anhydrase (CAc) in PNA+ ionocytes in trout that were subjected to metabolic alkalosis. This experiment revealed that the relative transcript abundance of CAc was significantly elevated in PNA+ ionocytes of alkalotic trout relative to that of control trout (P = 0.001; N = 7), a response that is consistent with the expected role of PNA+ ionocytes in compensation for systemic alkalosis.

O nitrato (NO3-) é um íon inorgânico que está presente naturalmente no meio ambiente, sendo a forma mais estável do nitrogênio oxidado. Devido a sua alta solubilidade em água, é possivelmente o contaminante das águas subterrâneas mais difundido no mundo, causando problemas de produção de água potável e distúrbios ecológicos. Neste contexto, o objetivo deste estudo consiste em investigar a capacidade de sorção do carvão granular comercial ativado, modificado quimicamente com CaCl2, para remoção de nitrato em soluções aquosas e avaliar a capacidade de regeneração do sorvente em diferentes condições. Com esta finalidade foram realizados ensaios de sorção e de dessorção predeterminando as melhores condições de processo: pH, tempo de residência e concentração de sólido sorvente. Ainda, isotermas de equilíbrio para este sistema foram construídas. Na dessorção do carvão ativado saturado com nitrato foram empregadas soluções de HCl, C6H8O7, NaOH, CaCl2 e H2O. Os ensaios de sorção resultaram nos parâmetros ótimos do processo de sorção: pH 6,0, tempo de 30min e concentração de sorvente igual a 20 g.L-1, utilizando soluções de nitrato com concentração inicial de 20 mg.L-1. Para regeneração, o tempo de residência aplicado foi de 30 min, e foram utilizados 400 mL de solução CaCl2 (2000 mg.L-1). Nestas condições, foi possível realizar vinte ciclos de sorção/regeneração (S/R), obtendo-se 54% de remoção de nitrato ao final destes ciclos. Durante a regeneração foi monitorada a concentração de Ca2+ na solução de CaCl2, objetivando manter a sua concentração inicial. Após 20 ciclos (S/R), o sorvente foi regenerado com 50 mL de solução de HCl 100 mg.L-1 e, em outra batelada, 50 mL de H2O 60ºC. Foram realizados mais 20 ciclos S/R para o sorvente regenerado com HCl e 20 ciclos S/R para o sorvente regenerado com H2O (60ºC). Índices médios de 58% de remoção de nitrato foram alcançados para ambos os processos ao final dos 20 ciclos (S/R). Foram realizados um total de 60 ciclos (S/R) com remoção média de 55% ao final do último ciclo. O modelo de isoterma de sorção que melhor se ajustou os dados experimentais foi o modelo de Langmuir, que forneceu a constante de energia ou afinidade do processo e também a acumulação máxima de nitrato no sorvente. / Nitrate (NO-3) is an inorganic ion which is present naturally in the environment, being the most stable form of oxidized nitrogen. Due to its high solubility in water, it is possibly the groundwater contaminant more widespread in the world, causing problems in the production of drinking water and ecological disturbances. In this context, the objective of this study is to investigate the sorption capacity of the commercial granular activated carbon, chemically modified with CaCl2 to remove nitrate from aqueous solutions and to study the regeneration capacity of the sorbent under different conditions. For this purpose tests of sorption and desorption were carried out, determining the optimal process conditions: pH, residence time and concentration of solid sorbent. Further, equilibrium isotherms for this system were built. In the desorption process of activated carbon saturated with nitrate, water (60°C) and aqueous solutions of HCl, C6H8O7, NaOH, CaCl2 were employed. The best sorption conditions found in the experiments were as follow: pH 6.0, time 30 min and concentration of sorbent 20 g.L-1, using nitrate solutions with initial concentration of 20 mg.L-1. For regeneration tests, the residence time was set as 30 min, using 400 mL of CaCl2 2000 mg.L-1 to keep Ca2+ in solution. Therefore, it was possible to perform twenty cycles of sorption/regeneration (S/R), yielding 54% nitrate removal at the end of these cycles. During regeneration, the concentration of Ca2+ in the CaCl2 solution was monitored. After 20 S/R cycles, the sorbent was regenerated with 50 mL of HCl solution (100 mg.L-1) or 50 mL of H2O at 60°C. Additionally, more 20 cycles (S/R) were performed for the regenerated sorbent with HCl solution or H2O (60°C). Maximum removal values of nitrate (58%) were achieved in both cases at the end of each 20 cycles (S/R). A total of 60 cycles (S/R) were performed, achieving nitrate removal of 55% at the end of the last cycle. The Langmuir sorption isotherm type was found to be the best fit to experimental data, providing the energy constant or affinity of the process and also the maximum accumulation of nitrate in the sorbent.

abstract: A tumor is a heterogeneous combination of proliferating tumor cells, infiltrating immune cells and stromal components along with a variety of associated host tissue cells, collectively termed the tumor microenvironment (TME). The constituents of the TME and their interaction with the host organ shape and define the properties of tumors and contribute towards the acquisition of hallmark traits such as hypoxia. Hypoxia imparts resistance to cancer from chemotherapy and radiotherapy due to the decreased production of reactive oxygen species and also promotes angiogenesis, malignant progression and metastasis. It also provides a powerful physiological stimulus that can be exploited as a tumor-specific condition, allowing for the rational design of anticancer hypoxia-activated pro-drugs (HAP). Accurate evaluation of tumor oxygenation in response to therapeutics interventions at various stages of growth should provide a better understanding of tumor response to therapy, potentially allowing therapy to be tailored to individual characteristics. The primary goal of this research was to investigate the utility of prospective identification of hypoxic tumors, by two different Magnetic Resonance Imaging (MRI) based oximetry approaches, in successful treatment with hypoxia activated therapy. In the present study, I report the utility of these two techniques 1) PISTOL (Proton Imaging of Siloxanes to map Tissue Oxygenation Levels) and 2) use of a hypoxia binding T1 contrast agent GdDO3NI in reporting the modulations of hypoxia pre and post hypoxia activated therapies in pre-clinical models of cancer. I have performed these studies in non-small cell lung cancer (NSCLC) and epidermoid carcinoma (NCI-H1975 and A431 cell lines, respectively) as well as in patient derived xenograft models of NSCLC. Both the oximetry techniques have the potential to differentiate between normoxic and hypoxic regions of the tumor and reveal both baseline heterogeneity and differential response to therapeutic intervention. The response of the tumor models to therapeutic interventions indicates that, in conjunction with pO2, other factors such as tumor perfusion (essential for delivering HAPs) and relative expression of nitroreductases (essential for activating HAPs) may play an important role. The long term goal of the proposed research is the clinical translation of both the MRI techniques and aiding the design and development of personalized therapy (e.g. patient stratification for novel hypoxia activated pro-drugs) particularly for cancer. / Dissertation/Thesis / Doctoral Dissertation Bioengineering 2017

Deficiencies in biotreatment due to uncontrolled growth of filamentous microorganisms is a problem for wastewater plants worldwide. The project was assigned with the task of reducing the growth of filamentous bacteria at the paper mill SCA Munksund. 12 bacteria and 1 fungi species were presented to the project as problematic due to their filamentous properties. Operating parameters affecting filamentous growth was examined and presented. The information gathered showed that a decrease in filamentous growth for 5 especially problematic bacteria could possibly be achieved by raising the DO, increasing the concentration of nutrients and decreasing the sludge age. Other parameters affecting the growth of filamentous bacteria, such as pH, temperature and F/M were found to be too diverse among the examined species. Alternative solutions not focused on finding optimal operating parameters was also investigated. Promising results were treatment using a feast-famine approach, installation of an anaerobic selector and ozonation of return sludge. A statistical analysis was also performed on operating data. Methods used were Principal component analysis, Clustering and Logistic regression. These were used as a proof of concept rather than providing meaningful data for an operating window.

Made available in DSpace on 2014-06-11T19:29:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-13Bitstream added on 2014-06-13T19:59:09Z : No. of bitstreams: 1 lima_vb_me_bauru.pdf: 784199 bytes, checksum: 9118a7fb6fa64317e37b932160bcf393 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As evidências de fármacos no meio ambiente têm se tornado um objeto de interesse por pesquisadores nos últimos anos. A maioria desses compostos tem sido encontrado em efluentes de estações de esgoto (ETE) municipais, águas superficiais e, em menor quantidade, em águas subterrâneas e água potável em todo o mundo. A presença de fármacos em corpos hídricos refletem alguns efeitos adversos incluindo toxidade aquática, desenvolvimento de resistência em bactérias patogênicas, genotoxicidade e desregulação endócrina. São diversas as fontes que podem ser causadoras para explicar o aparecimento de fármacos no ambiente aquático. Hoje, é conhecido que a principal fonte de poluição são os efluentes de ETEs. O fármaco utilizado neste estudo é o ácido Mefenâmico, um antiinflamatório não esteróide (AINEs) presente na formulação de diversos medicamentos comerciais, entre eles o Ponstan. A ineficiência dos processos de tratamento de água atuais na remoção deste composto motivou este trabalho considerando que a adsorção em carvão ativado em pó e oxidação via cloro como tecnologias complementares que podem ser implementadas nas ETEs. O estudo experimental consistiu na caracterização física do CAP e sua aplicação juntamente com a cloração, para avaliar a capacidade de removerem o ácido Mefenâmico / Evidences of pharmaceutical residuals in the environment has been come a topic of interest for researches in the last years. Most of these compounds have been found in the effluentes in municipal Sewage Water Treatment (SWT), surface water and in a lesse quantily in underground water and drinking water all over the world. The existents pharmaceutical residuals in water reflex some adverse affects including water toxicity, resistants the development in pathogenic bacteria, genotoxicities and endocrine dysfunctional. There are a number of sources that could be cause of explaining the appearing of pharmaceutical residuals in natural water. Today, it is known that the mean pollution source are the SWT effluents. The drug used in this study is the Mefenamic acid, present in the formulation of many commercial drugs, including Ponstan nonsteroidal anti-inflammatory drugs (NSAIDs). The inefficiency treatment processes of water present in the removal of this compound motivated this work whereas the adsorption on powdered activated carbon and chlorine oxidation pathway a complementary technologies that can be implemented is STPs. The experimental study was the physical characterization of the CAP and its application together with chlorination, to assess the ability of removing Mefenamic acid