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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

Estudo de marcação com iodo-131 de anticorpo monoclonal anti-CD20 usado na terapia de linfoma nao-hodgkin

AKANJI, AKINKUNMI G. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:27Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:38Z (GMT). No. of bitstreams: 0 / Linfomas são doenças originárias do sistema linfático, descritos por Thomas Hodgkin em 1932. São tradicionalmente classificados em dois grupos básicos: doenças de Hodgkin e linfomas do tipo não hodgkin (LNH). Inicialmente, pacientes com LNH foram tratados com radioterapia apenas ou combinada com imunoterapia usando-se anticorpo monoclonal anti-CD20 (ex., Rituximab-Mabthera, Roche). Porém, radioimunoterapia é uma nova modalidade de tratamento para pacientes portadores de LNH, na qual radiação citotóxica proveniente de radioisótopos terapêuticos é depositada nos tumores via anticorpos monoclonais (Acms). Este estudo concentrou-se nas condições de marcação do Acm anti-CD20 (Rituximab-Mabthera, Roche), com radioiodo (131I), pelo método direto, usando-se Cloramina-T como agente oxidante. Foram estudados parâmetros de marcação tais como: método de purificação, influência de tempo de incubação, influência de massa de agente oxidante, estabilidade in vitro e in vivo, imunoreatividade do anticorpo e distribuição biológica do anticorpo marcado em camundongos Swiss sadios. Produto de alta pureza radioquímica foi obtido, sem diferença notável entre os métodos aplicados. Não foi observada nenhuma influência direta do tempo de incubação na pureza radioquímica do anticorpo marcado. Um pequeno decréscimo na pureza radioquímica foi observado quando variou-se a massa do Acm sem variar a atividade do radioiodo. Após purificação, o anticorpo marcado apresentou pureza radioquímica de aproximadamente 100 %. Observou-se um produto de alta pureza radioquímica quando o anticorpo foi marcado na condição padrão. O anticorpo anti-CD20 apresentou variações de pureza radioquímica quando sua estabilidade foi testada em cinco condições estabilizadoras diferentes. Entretanto, a condição em que ácido gentísico foi combinado com congelamento demonstrou-se apropriada e capaz de minimizar os efeitos de autoradiólise do anticorpo marcado com alta atividade terapêutica de iodo-131. O anticorpo marcado apresentou imunoreatividade abaixo da relatada na literatura. A distribuição biológica em camundongos Swiss sadios revelou captação elevada no pulmão, fígado, e intestino delgado. O clareamento sanguíneo do anticorpo marcado foi relativamente rápido. Contudo, dados experimentais revelaram que anticorpos monoclonais anti-CD20 podem ser seguramente marcados com alta atividade de iodo-131 usando o método de Cloramina-T. O uso de cromatografia em camada delgada (ITLC-SG) na avaliação de pureza radioquímica mostrou-se apropriado, eficiente, prático, além de simples e rápido. O método de purificação utilizado demonstrou-se eficiente para a separação do anticorpo marcado do iodo livre. A abordagem inédita apresentada neste estudo, no sentido de viabilizar transporte e comercialização do produto marcado, referiu-se ao estudo de estabilidade do Acm marcado. A distribuição biológica do anticorpo demonstrou-se compatível com a distribuição do anticorpo íntegro indicando ótima estabilidade relativa in vivo. Os resultados deste estudo confirmam a potencialidade do anticorpo para a radioimunoterapia de linfomas do tipo não-Hodgkin. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
22

The Effect Of Free Chlorine And Chloramines On Lead Release In A Distribution System

Vasquez, Ferdinand 01 January 2005 (has links)
Total lead release in drinking water in the presence of free chlorine and chloramine residuals was investigated in field, laboratory and fundamental investigations for finished waters produced from ground (GW), surface (SW), saline (RO) and blended (B) sources. Field investigations found more total lead was released in the presence of chloramines than in the presence of free chlorine for RO and blended finished waters; however, there were no statistical differences in total lead release to finished GW and SW. Laboratory measurements of finished waters oxidation-reduction potential (ORP) were equivalent by source and were not affected by the addition of more than 100 mg/L of sulfates or chlorides, but were significantly higher in the presence of free chlorine relative to chloramines. Development of Pourbaix diagrams revealed the PbO2 was the controlling solid phase at the higher ORP in the presence of free chlorine and Pb3(CO3)2(OH)2(s) (hydrocerussite) was the controlling solid phase in the presence of chloramines at the lower ORP, which mechanistically accounted for the observed release of total lead as PbO2 is much less soluble than hydrocerussite. The lack of differences in total lead release to finished GW and SW was attributed to differences in water quality and intermittent behavior of particulate release from controlling solid films.
23

Atividade antifúngica, mecanismo de ação, citotoxidade e ação antibiofilme da cloramina T sobre Candida spp.

Ferreira, Gabriela Lacet Silva 17 August 2015 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-03-06T13:18:25Z No. of bitstreams: 1 arquivo total.pdf: 1622677 bytes, checksum: 4910b306e46e741a75cc3d2047affa2c (MD5) / Made available in DSpace on 2017-03-06T13:18:25Z (GMT). No. of bitstreams: 1 arquivo total.pdf: 1622677 bytes, checksum: 4910b306e46e741a75cc3d2047affa2c (MD5) Previous issue date: 2015-08-17 / Introduction: Faced with limitations to the use of sodium hypochlorite in the disinfection of dental prostheses and the need to control fungal proliferation in these sites, it is necessary to study new substances for this purpose. Objectives: To evaluate the antifungal activity, mechanism of action, cytotoxicity and antibiofilm action of chloramine T (CAT) on Candida spp. The minimum inhibitory concentration (MIC) of the substance on Candida albicans, Candida tropicalis, Candida krusei and Candida glabrata was determined by the microdilution technique and the minimum fungicidal concentration (CFM) was calculated through the subculture in Sabouraud Dextrose Agar (ASD) . The growth inhibition kinetics of C. albicans were evaluated by the method of counting colony forming units (CFU) at different times and concentrations. A microculture of C. albicans was performed on fowl agar plus tween 80 to evaluate the possible alteration of micromorphology against different concentrations of the substance. The possible mechanism of action on wall and fungal cell membrane was verified by the determination of MIC in the presence of sorbitol and ergosterol respectively. The inhibition of the initial adherence of fungal cells, formation and reduction of C. albicans biofilm were evaluated after short (1 min) and prolonged (8 h) contact with the substance and formation of the biofilm was measured by absorbance at 600 nm, Transformed into scores referring to the percentage of inhibition obtained based on the values ​​of the control group. The cytotoxicity of the substance was evaluated by the hemolysis method. Nystatin and sodium hypochlorite were used as positive controls. A descriptive and inferential analysis was performed considering α = 5%. Results: The CIM75% found for CAT was 781.3 μg / mL and the CFM / MIC ratio suggests a fungicidal activity against most of the strains tested, with probable action on cell wall and membrane. The substance showed immediate and prolonged action on the kinetic test and caused reduction of the filamentous form and inhibition of chlamydoconidia. In the biofilm assay, it presented similar results to sodium hypochlorite for inhibition of initial adherence and formation of mature biofilm (p> 0.05) and was more effective in reducing mature biofilm in the short contact groups at MIC concentration x2 (24 H) and CIM x 4 (48 h) (p <0.05). Conclusion: CAT shows antifungal activity on Candida spp. And shows fungicidal action on most of the strains tested. Its action is immediate and prolonged in the inhibition of C. albicans growth and probably occurs both in the wall and in the cell membrane. CAT causes alterations in the micromorphology of C. albicans and has antibiofilm activity, being effective in inhibiting the initial adherence of fungal cells, as well as in the formation and reduction of biofilm. / Introducao: Diante das limitacoes para o uso do hipoclorito de sodio na desinfeccao de proteses dentarias e da necessidade do controle da proliferacao fungica nestes sitios, faz-se necessario o estudo de novas substancias para este fim. Objetivos: Avaliar a atividade antifungica, mecanismo de acao, citotoxicidade e acao antibiofilme da cloramina T (CAT) sobre Candida spp. Materiais e Metodos: Foi determinada a concentracao inibitoria minima (CIM) da substancia sobre Candida albicans, Candida tropicalis, Candida krusei e Candida glabrata pela tecnica da microdiluicao e calculada a concentracao fungicida minima (CFM) atraves do subcultivo em Agar Sabouraud Dextrose (ASD). Foi avaliada a cinetica de inibicao do crescimento de C. albicans pelo metodo de contagem de unidades formadoras de colonias (UFC) em diferentes tempos e concentracoes. Foi realizado microcultivo de C. albicans em agar fuba acrescido de tween 80 para avaliacao da possivel alteracao da micromorfologia frente a diferentes concentracoes da substancia. O possivel mecanismo de acao sobre parede e membrana celular fungica foi verificado atraves da determinacao da CIM na presenca, respectivamente, de sorbitol e ergosterol. A inibicao da aderencia inicial de celulas fungicas, formacao e reducao do biofilme de C. albicans foram avaliados apos contato curto (1 min) e prolongado (8 h) com a substancia e a formacao do biofilme foi mensurada atraves de absorbancia a 600 nm, transformada em escores referentes a porcentagem de inibicao obtida com base nos valores do grupo controle. A citotoxicidade da substancia foi avaliada pelo metodo da hemolise. Nistatina e hipoclorito de sodio foram utilizados como controles positivos. Foi realizada analise estatistica descritiva e inferencial, considerando α=5%. Resultados: A CIM75% encontrada para a CAT foi de 781,3 µg/mL e a relacao CFM/CIM sugere uma atividade fungicida frente a maioria das cepas testadas, com provavel acao em parede e membrana celulares. A substancia mostrou acao imediata e prolongada no teste de cinetica e provocou reducao da forma filamentosa e inibicao de clamidoconidios. No ensaio do biofilme, apresentou resultados semelhantes ao hipoclorito de sodio para inibicao da aderencia inicial e formacao do biofilme maduro (p>0,05) e foi mais efetiva na reducao do biofilme maduro nos grupos de contato curto na concentracao CIM x 2 (24 h) e CIM x 4 (48 h) (p < 0,05). Conclusao: A CAT apresenta atividade antifungica sobre Candida spp. e apresenta acao fungicida sobre a maioria das cepas testadas. Sua acao e imediata e prolongada na inibicao do crescimento de C. albicans e provavelmente ocorre tanto em parede quanto em membrana celular. A CAT causa alteracoes na micromorfologia de C. albicans e possui atividade antibiofilme, sendo efetiva na inibicao da aderencia inicial das celulas fungicas, bem como na formacao e reducao do biofilme.
24

Swimming pool water treatment with conventional and alternative water treatment technologies

Skibinski, Bertram 12 March 2018 (has links) (PDF)
To mitigate microbial activity in swimming pools and to assure hygienic safety for bathers, pool systems have a re-circulating water system ensuring continuous water treatment and disinfection by chlorination. A major drawback associated with the use of chlorine as disinfectant is its potential to react with organic matter (OM) present in pool water to form potentially harmful disinfection by-products (DBP). In this thesis, the treatment performance of different combinations of conventional and novel treatment processes was compared using a pilot scale swimming pool model that was operated under reproducible and fully controlled conditions. The quality of the pool water was determined in means of volatile DBPs and the concentration and composition of dissolved organic carbon (DOC). Further, overall apparent reaction rates for the removal of monochloramine (MCA), a DBP found in pool water, in granular activated carbon (GAC) beds were determined using a fixed-bed reactor system operated under conditions typical for swimming pool water treatment. The reaction rates as well as the type of reaction products formed were correlated with physico-chemical properties of the tested GACs.
25

Swimming pool water treatment with conventional and alternative water treatment technologies

Skibinski, Bertram 22 February 2017 (has links)
To mitigate microbial activity in swimming pools and to assure hygienic safety for bathers, pool systems have a re-circulating water system ensuring continuous water treatment and disinfection by chlorination. A major drawback associated with the use of chlorine as disinfectant is its potential to react with organic matter (OM) present in pool water to form potentially harmful disinfection by-products (DBP). In this thesis, the treatment performance of different combinations of conventional and novel treatment processes was compared using a pilot scale swimming pool model that was operated under reproducible and fully controlled conditions. The quality of the pool water was determined in means of volatile DBPs and the concentration and composition of dissolved organic carbon (DOC). Further, overall apparent reaction rates for the removal of monochloramine (MCA), a DBP found in pool water, in granular activated carbon (GAC) beds were determined using a fixed-bed reactor system operated under conditions typical for swimming pool water treatment. The reaction rates as well as the type of reaction products formed were correlated with physico-chemical properties of the tested GACs.
26

Molecular biology of cytotoxic stress-induced protein modification in mammalian cells

Salama, Samir Abdalla Hamed 17 December 2010 (has links)
No description available.
27

Examining Aspects of Copper and Brass Corrosion in Drinking Water

Murray-Ramos, Nestor Agustin 02 February 2007 (has links)
As the water industry complies with the new arsenic standard and new treatments are installed, unintended consequences might be expected in relation to corrosion control when sulfate/chloride ratio, pH, phosphate, iron, aluminum, bicarbonate and organic matter levels are altered. In some cases, these changes will be beneficial and in other detrimental. This research project is the first to systematically evaluate the effect of some key changes in the chemistry of the treated water in relation to copper and brass corrosion control. A 1.25 year pipe rig experiment was executed to anticipate effects of arsenic treatment on copper pinholes in 10 representative waters. The control water will mimic a synthesized version of Potomac River that is extremely aggressive to copper. Consistent with prior research that pitting is driven by free chlorine in this water and inhibited by phosphate, substitution of chloramine for chlorine or dosing of phosphate completely eliminated deep pits on tubes for the duration of the experiment. Chlorine caused serious pitting if NOM was less than 0.3 mg/L over a range of Cl:SO4 ratio's. Pitting seemed to occur under deposits of iron or aluminum on the copper surface, and if anything, an equimolar amount of iron caused worse pitting than aluminum. Amendment of the aggressive water with 3 mg/L NOM eliminated growth of deep pits (> 0.05 mm). While brass pipes (containing 0.09% lead, 63% copper and 36% zinc) was attacked non-uniformally by an aggressive water at high pH and with high Cl2 content, no significant pitting occurred at any condition tested, even though pitting did occur for copper exposed to the exact same water. The implication is that zinc in the alloy may help to prevent non-uniform attack on copper and copper alloys. The ban on lead-containing plumbing materials in the Safe Drinking Water Act (1986) and the EPA Lead and Copper Rule (1991) have successfully reduced lead contamination of potable water supplies. This part of the work carefully re-examined the lead contamination concern from the standpoint of existing performance standards for brass. The ANSI/NSF 61, Section 8 standard is relied on to protect the public from in-line brass plumbing products that might leach excessive levels of lead to potable water. Experiments were conducted to look at the practical strictness of these test-standards. In-depth study of the standard revealed serious flaws due from the use of a phosphate buffer and a failure to control carbonate dissolution from the atmosphere in the test waters. In order to help prevent undesirable outcomes in the future, standard's improvements are needed to assurance that brass devices passing this test are safe. / Master of Science
28

Occurrence des sous-produits de la désinfection dans l'eau des piscines publiques de la ville de Québec

Simard, Sabrina 16 April 2018 (has links)
La baignade en piscine est l'une des activités aquatiques les plus pratiquées par la population. Comme dans les eaux naturelles, l'eau des piscines publiques peut contenir des contaminants de nature microbiologique et chimique. Ce mémoire vise l'étude de contaminants chimiques et particulièrement la présence des sous-produits de la désinfection (SPD) dans les piscines municipales. Les résultats démontrent que la formation de SPD tels que 'les trihalométhanes (THM), les acides haloacétiques (AHA) et les chloramines (CAMi) est considérable dans les piscines. En effet, les niveaux de SPD mesurés dans les piscines sont plus élevés que ceux retrouvés dans l'eau potable. De plus, le type de piscine (intérieure ou extérieure) a également une influence sur l'occurrence des SPD. D'autres facteurs liés à la gestion des piscines tels que la fréquentation des bassins, le taux de renouvellement de l'eau et les doses de chlore ajoutées semblent favoriser la formation et la variabilité des SPD dans les piscines. Conséquemment, la baignade dans les piscines publiques intérieures et extérieures peut constituer une voie importante d'exposition aux SPD pour la population.

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