The Toxic Effects Of Xenoestrogens On Cytoskeletal Proteins

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2005Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2005Ksenoöstrojenler endojen hormonları taklit edebilir ya da endokrin prosesleri etkileyebilirler, bu nedenle endokrin bozucu olarak adlandırılırlar. Bu çalışmanın konusu olan Bisphenol A (BPA) bir endokrin bozucudur. BPA polikarbonat, epoksi ve diğer rezinlerin monomeridir. BPA bu kaynaklardan açığa çıkarak insanlar ve doğal hayatın maruz kaldığı çevresel bir toksik ajan oluşturur. BPA reprodüktif sistem anomalilerine neden olmaktadır ve çeşitli sistemler üzerinde de birçok yan etkisi bulunmaktadır. BPA’nın hücrede iğ mikrotubulleri, mikrotubul-ilişkili proteinleri, kinetokorları, sentromer, sentrozom ve sentriolleri ve DNA’yı hedef aldığı önerilmektedir. Mikrotubul polimerizasyon ve depolymerizasyon dinamikleri gerek bölünen gerekse bölünmeyen hücrelerde normal hücresel fonksiyonun ve morfolojilerin sağlanmasında çok önemli rol oynarlar. Bu çalışmada BPA’nın mikrotubuller üzerindeki etkileri araştırıldı. Mikrotubul proteinleri taze dana beyninden elde edildi. BPA’nın mikrotubul polimerizasyon ve depolimerizasyon özellikleri üzerindeki etkilerini incelemek amacıyla sedimentasyon deneyleri, floresans spektroskopi ve elektron mikroskopi teknikleri kullanıldı.Xenoestrogens can mimic endogenous hormones or interfere with endocrine processes hence they are called “endocrine disrupters”. Bisphenol A (BPA) which is the subject of this study is an endocrine disrupter. BPA is monomers of polycarbonate, epoxy and other resins. BPA is an environmental toxicant since it can be released from these sources, resulting in human and wildlife exposure. BPA causes reproductive system abnormalities and it has also several adverse effects on various systems. BPA is proposed to target spindle microtubules, microtubule-associated proteins, kinetochores and centromeres, centrioles and centrosomes, as well as DNA in the cell. Microtubule assembly and disassembly dynamics are crucial for both dividing and non-dividing cells in maintaining normal cellular function and morphologies. In this study, the effects of BPA on microtubules were investigated. Microtubule proteins were obtained from fresh bovine brain. To analyze the effects of BPA on microtubule assembly and disassembly properties, sedimentation assays, fluorescence spectroscopy and electron microscopy techniques were used.Yüksek LisansM.Sc

Verhalten von Mikroschadstoffen bei der Hydrothermalen Karbonisierung von Klärschlamm

Die Hydrothermale Karbonisierung (HTC) wird seit einigen Jahren als vielversprechende Methode zur Umwandlung von organischen Reststoffen eingesetzt. Durch das Erhitzen einer wässrigen Suspension auf 190 - 250 °C unter Luftausschluss findet bei einem Druck von ca. 15 bar die Umwandlung zu Biokohle statt. Der Einsatz von Klärschlamm in der HTC wird erst seit Kurzem durchgeführt. Vorteile sind eine verbesserte Entwässerbarkeit und ein höherer Brennwert. Darüber hinaus werden die Möglichkeit zur Nährstoffrückgewinnung und eine Reduktion von Schadstofffrachten postuliert. Letztere Hypothese wurde in dieser Arbeit geprüft. Als relevante Stoffgruppen wurden aufgrund ihrer Umweltrelevanz und Persistenz zwölf Arzneimittel sowie die Gruppe der perfluorierten Tenside (PFT) ausgewählt. Zunächst mussten Methoden der Flüssigchromatographie gekoppelt mit Massenspektrometrie (LC-MS) für die Quantifizierung der Substanzen in den Matrices Klärschlamm und Biokohle entwickelt werden. Matrixeffektchromatogramme machten dabei die Komplexizität der Matrix sichtbar. Die finale Analysenmethode von Arzneimitteln in Klärschlamm und Biokohle basierte auf einer Probenvorbereitung mittels Gefriertrocknung und beschleunigter Lösemittelextraktion. Die Extrakte wurden direkt injiziert und die gesuchten Substanzen mittels Standardaddition quantifiziert. Zur Untersuchung der PFT wurde ein zusätzlicher Aufreinigungsschritt mittels Festphasenextraktion integriert. Bei der Untersuchung von Klärschlämmen und dazugehörigen Biokohlen nach HTC zeigte sich, dass die Klärschlämme eine höhere Belastung mit Arzneimitteln und PFT aufwiesen als die entsprechenden Biokohlen. Daraus ergab sich eine Reduktion der Schadstofffracht durch die HTC. Die Reaktionsmechanismen, die zu dieser Reduktion führten, wurden am Beispiel von Diclofenac genauer untersucht. Hierzu wurde in Inertexperimenten mit Sand das Abbauverhalten der Substanz bei der HTC betrachtet. Non-target Analytik mittels hochauflösender Massenspektrometrie (LC-HRMS) half bei der Identifizierung von Transformationsprodukten. Daraus konnte ein Abbaumechanismus für Diclofenac postuliert werden. Die Übertragung der Ergebnisse aus Interexperimenten auf die komplexe Klärschlammmatrix erfolgte in einem nächsten Schritt. Das Verhalten von Diclofenac in Realproben zeigte allerdings deutliche Diskrepanzen, deren Ursachen nicht vollständig aufgeklärt werden konnten. Insgesamt stellt diese Arbeit die Entwicklung von LC-MS Methoden zur Analyse von Spurenstoffen in Klärschlamm und Biokohle dar. Die Untersuchung von Realproben ergab, dass die HTC geeignet ist, Spurenstoffe aus Klärschlamm zu reduzieren. Für Diclofenac konnte ein Reaktionsmechanismus postuliert werden. Damit verknüpft diese Arbeit die Entwicklung analytischer Methoden für komplexe Umweltproben mit der Bewertung neuartiger Behandlungsverfahren wie der HTC. Darauf aufbauend können weiterführende Studien das Verhalten anderer Stoffgruppen bei der HTC untersuchen oder die Anwendung der produzierten Biokohle in der Landwirtschaft bewerten.Hydrothermal carbonization (HTC) has become a promising process for treating residual and waste materials. Heating up the aqueous matter to 190 - 250 °C in a closed system at about 15 bar converts the material to biochar. Use of sewage sludge in the HTC process has emerged recently. Compared to sewage sludge the biochar from HTC has an enhanced dewaterability and an increased heating value. Moreover, proponents claim that nutrients enrich in the biochar and pollutants degrade during the process. In this thesis the latter assumption was examined. Twelve pharmaceuticals from different compound classes and ten perfluorinated compounds (PFC) were selected because of their ecological relevance and persistence. First, liquid chromatography coupled to mass spectrometry (LC-MS) methods were developed for the selected compounds in sewage sludge and biochar from HTC. Matrix effect profiles visualized the sample complexity. Final methods for the analysis of pharmaceuticals included sample lyophilization and pressurized liquid extraction. Extracts were injected directly to LC-MS and quantified via standard addition. Analysis of PFC required an additional clean-up step via solid phase extraction. Analysis of pharmaceuticals and PFC in sewage sludge from different wastewater treatment plants and their resulting biochars showed that the sewage sludges contained higher amounts of the analytes than their corresponding biochars. Hence, HTC could reduce the micropollutant load in sewage sludge. Although compound loads followed regional trends, the removal rates remained independent from the sewage sludge source. The mechanisms causing the compound decline were followed in detail by the example of diclofenac. Therefore, the compound was examined in inert HTC experiments, whereby sand replaced the sewage sludge. Non-target analysis using high resolution mass spectrometry (LC-HRMS) helped to identify transformation products. Therewith a degradation mechanism for diclofenac during HTC was postulated. Based on that, results were transferred to the complex sewage sludge matrix. However, behavior of diclofenac during HTC of sewage sludge differed significantly from the inert experiments. The reasons for these discrepancies could not be fully revealed. Altogether, this thesis presented LC-MS methods to determine micropollutants in sewage sludge and biochar. Sample analysis showed that the HTC could reduce micropollutants in sewage sludge by converting it to biochar. The process was followed mechanistically for diclofenac. Therewith, this work connects developing new analytical LC-MS methods with assessing novel processes like the investigated HTC. Based on that, further studies could investigate the behavior of other compound classes. Further on, the application of the produced biochar in agriculture could be examined

Mejoramiento de propiedades físico-mecánicas del concreto f’c = 210 kg/cm2 con adición de vidrio y caucho reciclado, Lima – 2022

Uno de los temas más apremiantes actualmente son las viviendas autoconstruidas, las cuales presentan agrietamientos, entre otras fallas estructurales exponiendo la vida de las personas, este problema se debe al inadecuado proceso constructivo. El presente estudio tiene como objetivo, analizar las propiedades fisco-mecánicas del concreto f’c = 210 kg/cm2 con adición de vidrio y caucho reciclado (VCR), buscando promover la utilización de nuevas alternativas con el fin de mejorar sus propiedades del concreto, el desarrollo se inició con la obtención del material reciclado, siendo el vidrio a través de botellas y el caucho mediante neumáticos, para luego elaborar los diseños de mezcla y poder determinar sus características físicas y mecánicas del concreto. Esta investigación es de tipo aplicada, enfoque cuantitativo, diseño experimental – cuasi experimental y de nivel correlativo, su población son todos los concretos de diseño f’c = 210 kg/cm2 con adición de VCR, con una muestra de 36 especímenes cilíndricos y 12 vigas prismáticas con adición de 0%, 5%, 10% y 15% de VCR para ser ensayadas en laboratorio y determinar sus propiedades físico-mecánicas. Concluyendo que los resultados más óptimos se alcanzaron con la adición de 5% y 15% de vidrio y caucho reciclado, ya que mejoró su revenimiento e incremento su densidad del concreto en estado fresco, respecto a las propiedades mecánicas, el contenido óptimo se logró con dosificación de 5% de VCR, donde la resistencia a compresión logró incrementar un 4.23% y su resistencia a flexión incremento 6.01% respecto a la mezcla patrón a los 28 días

Ferritas de pilha aplicadas na remoção de azul de metileno e desenvolvimento de um protótipo de um reator para o processo foto-Fenton heterogêneo.

Problemas ambientais como o descarte inadequado das pilhas utilizadas que geram contaminação de solo e águas freáticas com metais pesados, e de corantes das indústrias têxtil, os quais são perdidos após o processo de tingimento e podem alcançar águas naturais, necessitam de novas alternativas de tratamento e mitigação. Umas das recentes alternativas para o tratamento de efluentes são os processos foto-Fenton heterogêneos, que oferecem vantagens como o aproveitamento da energia solar, alta eficiência, e fácil etapa de recuperação do catalisador, reduzindo os custos associados a etapas de pós-tratamento e oferecendo maior viabilidade ao processo. Este trabalho teve como objetivo avaliar as ferritas de Zn/Mn obtidas a partir de pilhas descartadas em aplicações fotocatalíticas utilizando-as como catalisador no processo foto-Fenton heterogêneo para degradar o corante azul de metileno (AM). Pretende-se desenvolver um protótipo de reator onde as ferritas estejam suportadas magneticamente e que o tratamento do efluente seja em fluxo contínuo. Nos ensaios em batelada determinaram-se os valores de reagentes para se atingir a condição ótima do processo 10 mmolLˉ¹ de H₂O₂, 0,1% mvˉ¹ de ferrita, tempo de residência de 2 horas e área superficial de exposição 0,7 cm² por mL de solução. Não houve necessidade de agitação ou refrigeração. Nestes ensaios atingiram-se valores superiores a 98% de remoção de AM sob irradiação de 20-40 Jcmˉ² e total remoção de cor para a mesma dose de energia. Os experimentos controles não apresentaram degradação significativa, assim como o experimento para avaliar a adsorção do AM no catalisador, demonstrando o potencial do catalisador desenvolvido. Com base nesses resultados, desenvolveu-se um reator em fluxo contínuo com o catalisador suportado externamente por imãs. Neste reator, com volume de residência de 1,0 L e uma vazão de aproximadamente 6 mLminˉ¹ de solução, foi possível degradar AM em fluxo contínuo com uma eficiência de remoção maior que 95% e total remoção da cor desde que se garanta a dose de energia entre 30 e 40 Jcmˉ²( aprox. duas horas de irradiação). Nesta condição, atingiu-se uma redução de COT próxima a 60%. Por outro lado, como o catalisador está suportado em um imã, não há perda de ferro para o ambiente e também não há formação de lodo de hidróxido de ferro evitando assim pós-tratamentos para recuperação de ferro

Nuclear stopping and flow in heavy ion collisions and the in-medium NN cross section

We present transport calculations for heavy ion reactions in which the mean field and the in-medium nucleon-nucleon cross section are consistently based on the same effective interaction, i.e. the in-medium T-matrix from microscopic Dirac-Brueckner calculations. Doing so, the stopping in central reactions in terms of the recently proposed $var_{\rm tl}$ observable and the correlation to the behavior of the directed flow is investigated. The relation to the nuclear shear viscosity is discussed.Comment: 9 pages, 4 figure

Quantum chromodynamics quark benzene

A six-quark state with the benzene-like structure is proposed and studied based on color string model. The calculation with the quadratic confinement show that such structure has the lowest energy among the various hidden color six-quark structures proposed so far. Its possible effect on $NN$ scattering is discussed.Comment: 5 pages, 7 figure