Previous studies demonstrated that coplanar PCBs promote inflammation by release of pro-inflammatory cytokines like TNF, MCP-1, and VCAM-1 from endothelial cells as well as adipocytes. Also these PCBs at small doses may contribute to the development of obesity by inducing adipocyte differentiation. Obesity is a known risk factor that promotes cardiovascular disorders like atherosclerosis and AAAs. Evidence shows Ang II, a component of the RAS, leads to the formation of atherosclerosis and AAAs in both normal as well as hyperlipidemic mice. Earlier studies in our laboratory have also shown that coplanar PCB-77 promotes atherosclerotic lesion formation in ApoE-/- mice. The purpose of this study was to define the effects of PCB77 on Ang II induced vascular diseases like atherosclerosis and AAAs. Two different hyperlipidemic mouse models, which require different diets to get atherosclerosis, the ApoE deficient mice (ApoE-/-) requiring the normal mouse diet (Chow diet) and the Low Density Lipoprotein Receptor deficient mice (LDLr-/-) requiring the Western diet, were used for this study as both are susceptible to Ang II induced vascular disorders. The timing of PCB administration was also studied in LDLr-/- mice to see the profound effects of PCB77 on atherosclerosis and AAAs.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 173-180).

Made available in DSpace on 2014-12-17T14:08:49Z (GMT). No. of bitstreams: 1 VilmaAC_DISSERT_PARCIAL.pdf: 283414 bytes, checksum: 221724a56ff323c23efa132cc9f62484 (MD5) Previous issue date: 2011-02-03 / Crude oil has between 0.04 up to 5% of sulphur, the higher the oil the higher the sulphur levels. Sulphur usually gives problems such as corrosion in refinery, and once burnt produces SO2 that goes to atmosphere. This work aim to investigate the capacity of Rhodococcus rhodochrous (NRRL B-2149) to metabolize the model compound 4-methyldibenzotiophene (4-MDBT), to remove the sulphur and transform it in 2-hydroxybiphenyl (2-HBF) and sulphite using the 4S pathway. Kynetic runs were carried out in shaker at 120 rpm and 32?C. Samples were taken every 12h to assay substrate consume as well as cells production using HPLC. Results showed that R. rhodochrous NRRL B-2149 can use the 4S pathway in order to remove sulphur without change the carbon chain of the molecule as well as that cells and 4-MDBT affects the product formation. The production of 2-hydroxybiphenyl has interest for industry once it is a potent biocide. However, evaluation is necessary in order to obtain better results compatible with industry needs / O petr?leo bruto convencional cont?m entre 0,04 a 5% de enxofre, e em geral ?leos mais densos apresentam teores mais elevados. Embora pequena, esta fra??o ? importante e sua presen?a torna-se indesej?vel, tanto por promover a corros?o do equipamento da refinaria, como porque parte dela persiste na composi??o dos derivados, que, ao serem queimados, liberam di?xido de enxofre (SO2) para a atmosfera. Este ? um dos principais poluentes atmosf?ricos, respons?vel pelas chuvas ?cidas. O presente trabalho teve como objetivo avaliar a capacidade da cepa Rhodococcus rhodochrous (NRRL B-2149) em metabolizar o composto modelo 4-metildibenzotiofeno (4-MDBT), remover-lhe o ?tomo de enxofre e convert?-lo em 2-hidr?xibifenil (2-HBF) e sulfito utilizando a via sulf?xido-sulfona-sulfonato-sulfato ( 4S ), sem reduzir significativamente seu poder calor?fico. Para essa avalia??o foi realizado um estudo cin?tico em incubador rotativo sob agita??o de 120 rpm e 32?C. As amostras foram retiradas em intervalos de 12 h para an?lise da concentra??o celular e consumo de substrato e quantificadas por cromatografia l?quida. Os resultados mostraram que a cepa de R. rhodochrous NRRL B-2149 ? capaz de utilizar a Via 4S para remover o enxofre do composto sem contudo, alterar sua cadeia carb?nica e que a concentra??o de c?lulas e de 4-MDBT interferem na forma??o do produto 2-HBF. A produ??o do 2-hidroxibifenil detectada neste estudo ? de grande relev?ncia j? que ele ? um biocida potente de interesse industrial. No entanto, avalia-se condi??es dos ensaios visando obter concentra??es vi?veis para amplia??o industrial / 2020-01-01

Bifenilas Policloradas (PCB) são compostos orgânicos clorados altamente tóxicos e também são considerados poluentes orgânicos persistentes. Sua alta estabilidade térmica e química é responsável pela sua difícil degradação, e quando estas substâncias são liberadas no meio ambiente, sua acumulação nos ecossistemas incorpora-se na cadeia alimentar, exibindo biomagnificação. Deve-se ressaltar a importância para o meio ambiente do tratamento de resíduos com PCB. Considerando que a Convenção de Estocolmo sobre poluentes orgânicos persistentes (POP) estabeleceu a eliminação do uso de PCB em equipamentos, por exemplo, transformadores e capacitores elétricos, até 2025. O objetivo deste trabalho foi estudar a remoção de PCB pelos processos de extração usando fluido supercrítico e a extração convencional (Soxhlet) no tratamento de materiais contaminados com PCB. Assim foi desenvolvida uma ferramenta computacional para correlacionar os dados de solubilidade de PCB em CO₂ supercrítico, usando a equação de estado de Peng-Robinson com parâmetros ajustados. O procedimento de cálculo foi inicialmente usado para uma série de compostos aromáticos (naftaleno, antraceno, fenantreno e bifenil), a fim de testar a abordagem. Os parâmetros binários para a regra de mistura quadrática clássica (vdW2) foram sistematicamente estimados, juntamente com um novo conjunto de dados de pressão de vapor, a fim de descrever a dependência da temperatura e alcançar incertezas experimentais. Finalmente, foram utilizados os parâmetros estimados para simular valores de solubilidade dos principais congêneres constituintes das misturas comerciais reais de PCB, como função das condições de operação de extração com uma solução simultânea das equações de equilíbrio para cada composto. A modelagem termodinâmica demonstrou ser viável para a análise de processos. / Polychlorinated Biphenyls (PCB) are chlorinated organic compounds which are highly toxic and are also considered persistent organic pollutants. The high thermal and chemical stability of PCB are responsible for their hard degradation, and when these substances are liberated in the environment, their accumulation in ecosystems leads to their incorporation in the food chain, exhibiting biomagnification. It should be emphasized the environmental importance for treating wastes with PCB. Considering that, Stockholm Convention on persistent organic pollutants (POP) established the elimination of the use of PCB in equipments, e.g. electrical transformers and capacitors, by 2025. The objective of this work was to study the removal of PCB by the processes of extractions using supercritical fluid and conventional (Soxhlet) extraction method in the treatment of contaminated materials with PCB. As well was the formulation of a computational tool to correlate solubility data of PCB in supercritical CO₂, using Peng-Robinson equation of state with fitted parameters. The calculation procedure was initially used for a series of aromatic compounds (naphthalene, anthracene, phenanthrene and biphenyl) in order to test the approach. The binary parameters for the classical quadratic mixing rule (vdW2) were systematically estimated, together with a new set of vapor pressure in order to describe the temperature dependence and achieve experimental uncertainties. Finally, the estimated parameters were used to simulate solubility values of the major constituent congeners of commercial and real mixtures of PCB, as function of the operational conditions of extraction by a simultaneous solution of the equilibrium equations for each compound. The thermodynamic modeling demonstrated to be feasible for process analysis and design.

Fossil fuels are currently the primary industrial energy source on Earth. They are principally composed of complex hydrocarbons in either long-chain or cyclic conformation. Industrial use of petroleum, diesel, oil, tar and other coal-derived products inevitably leads to pollution of the environment. The most serious pollution is caused by polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) that are not easily removed from soil after a spill. Long-chain and cyclic conformation makes fossil fuel hydrocarbons difficult to break down. However, certain free-living soil microorganisms have adapted to utilising these PAHs/PCBs as a source of energy. In many cases, their efficacy is greatly enhanced by the presence of plants. By inhabiting the rhizosphere, microbes form a mutualistic relationship with the plant, receiving nutrients from it and in return providing a less polluted environment in which the plant can grow. The purpose of this study was to elucidate some of the microbial population diversity in PAH/PCB-polluted soils in South Africa through the use of denaturing gradient gel electrophoresis (DGGE). In an initial study, DGGE was employed to separate soil communities in polluted and unpolluted soils into a genetic fingerprint, the main bands of which were sequenced and subjected to a BLAST analysis through a database for possible identification of species present. Phylogenetic and distance studies indicated that unpolluted soils have a far greater species diversity. It thus was evident that PAH/PCB pollution of soil leads to a decrease in microbial diversity by selecting for microorganisms with the ability to activate metabolic pathways allowing them to utilise the pollutants as an alternative source of carbon. Population diversity of pro- and eukaryotes found within polluted and non-polluted soils was compared. DGGE was employed to determine the genetic fingerprint of each population. Following this, dendogram analyses based on Shannon indices were done to determine PAH breakdown potential of prokaryotic vs. eukaryotic communities. A higher diversity and better adaptation potential were evident within prokaryotic than eukaryotic communities in pollution-stressed environments, indicating that the prokaryotic component of these samples had the greatest PAH-metabolism potential. To determine the capacity for PAH/PCB metabolism by the organisms within the soil samples being studied, the presence of xylE and ndoB genes, responsible for toluene/xylene and naphthalene biodegradation, respectively, was determined. DGGE was performed to analyse genetic diversity between these two genes, based on community fingerprints. Polluted soil communities tended to have comparable community diversity within their functional genes, depending on their physical situation, plant species proximity and soil conditions. In general, soil contained indigenous microbes with a high natural potential for biodegradation of PAHs/PCBs. A portion of the 16S gene of eight bacterial isolates representing the most dominant culturable taxa in the polluted soils was sequenced and analysed for identification purposes. These identifications were conducted in conjunction with the use of the catabolic gene probes xylE and ndoB to establish the hydrocarbon degrading capacity of the isolates. Pseudomonas, from the rhizosphere of Cyperus esculentus, was the most common PAH-degrading genus found in this study. Considering the well-established rhizosphere competence and PAH-degrading capacity of Pseudomonas, this genus seems to be the best suited for bioaugmentation purposes in South Africa. The presence of the nifH gene, the general marker gene of nitrogen-fixing bacteria in communities from unpolluted and polluted soils, was determined. It was hypothesised that bioremediation could be enhanced by nitrogen addition to polluted environments. Nested-PCR of the nifH gene was conducted on a diagnostic basis and was followed by DGGE of the product to determine the functional gene diversity within pollution-dwelling, nitrogen-fixing bacterial communities. Nitrogen-fixing microorganisms were present in all the soils sampled but, in only 80% of the pure cultures isolated from polluted and unpolluted soils and rhizospheres. Although different rhizospheres and pollutants were examined, it was found that of the polluted soils studied, most nifH gene diversity of polluted soils existed within machinery oil polluted, wood chip mulched, non-rhizosphere soil. Thus, it would appear that the more polluted the soil the higher the free microbe nitrogen fixation diversity possibly due to environmental stress. / Thesis (PhD (Microbiology))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted

Polychlorinated biphenyls (PCBs) continue to pose a health concern because of their predominance in the diet and air as well as in environmental samples and humans. PCB congeners with 3 or 4 chlorine substituents in ortho position have been associated with neurodevelopmental disorders. Hydroxylated metabolites (OH-PCBs) of these PCBs are also potentially toxic to the developing brain. Metabolism studies have mainly focused on animal models. However, preliminary data from this dissertation work have revealed PCB metabolism differences between laboratory animal models and humans in terms of metabolite profiles, chiral signatures. More concerning, biotransformation of chiral PCBs is poorly investigated in humans. The objective of this dissertation research was to study the biotransformation of chiral and prochiral PCBs to chiral hydroxylated metabolites in humans and rats and to identify individual human P450 enzymes involved in the metabolism of these PCBs. I chose chiral PCB congeners 2,2',3,4',6-pentachlorobiphenyl (PCB 91); 2,2',3,5',6-pentachlorobiphenyl (PCB 95), 2,2',3,3',4,6'-hexachlorobiphenyl (PCB 132) and 2,2',3,3',6,6'-hexachlorobiphenyl (PCB 136) for this investigation because they are environmentally relevant and their metabolism has been studied in rodents and other laboratory animal species (Kania-Korwel et al., 2016a). Prochiral PCB congeners 2,2′,4,6′-tetrachlorobiphenyl (PCB 51) and 2,2′,4,5,6′-pentachlorobiphenyl (PCB 102) were selected because their considerable presence in technical PCB mixtures. To test the hypothesis that P450 enzyme and species differences mediate the congener-specific enantioselective metabolism of chiral PCBs to hydroxylated metabolites, I sought to establish structure-metabolism relationships by studying the enantioselective metabolism of structurally diverse chiral PCBs by human liver microsomes (HLMs). Racemic PCB 91, PCB 95 and PCB 132 were incubated in vitro with pooled or individual donor HLMs at 37 °C, and levels and chiral signatures of the parent PCB and its hydroxylated metabolites were determined by high-resolution gas chromatography equipped with time-of-flight mass spectrometry (GC/TOF-MS) or electron capture detection (GC-ECD). Hydroxylated metabolites formed were identified and metabolic schemes for these PCBs proposed. I found inter-individual differences in the formation of OH-PCBs by individual donor HLMs. Comparison of the metabolite profiles of PCB 91, PCB 95, PCB 132 and PCB 136 (PCB 136 metabolism by HLMs was investigated by other researchers) revealed congener-specific differences in the oxidation of PCBs by human cytochrome P450 enzymes. PCB 91 and PCB 132 were mainly hydroxylated in meta position, with the 1,2-shift metabolites being the major metabolites formed from both PCB congeners by HLMs. In contrast, PCB 95 and PCB 136 were primarily hydroxylated in the para position. Moreover, we determined human P450 isoforms involved in the metabolism of neurotoxic PCBs using in silico and in vitro approaches. In silico predictions suggested that chiral PCBs are metabolized by CYP1A2, CYP2A6, CYP2B6, CYP2E1, and CYP3A4. Experimentally we found that CYP2A6, CYP2B6 and to a minor extent CYP2E1 were the enzymes involved in the metabolism of these chiral PCBS. We also investigated nonchiral sources of chiral OH-PCBs by studying the P450- and species-dependent biotransformation of prochiral PCB 51 and PCB 102 to chiral OH-PCB metabolites. Prochiral PCB 51 and PCB 102 were incubated with liver microsomes prepared from male Sprague-Dawley rats pretreated with various inducers of P450 enzymes including phenobarbital (PB), dexamethasone (DEX), isoniazid (INH), β-naphthoflavone (BNF), clofibric acid (CFA) or corn oil (CO); and untreated male cynomolgus monkeys, Hartley albino guinea pigs, New Zealand rabbits, golden Syrian hamsters; and untreated female Beagle dogs. PCB 51 and PCB 102 were metabolized to 2,2',4,6'-tetrachlorobiphenyl-3'-ol (OH-PCB 51) and 2,2',4,5,6'-pentachlorobiphenyl-3'-ol (OH-PCB 102), respectively. The formation of both metabolites was P450 isoforms- and species-dependent. Moreover, OH-PCB 51 and OH-PCB 102 were chiral and were formed enantioselectively in all microsomes investigated. Taken together, my findings demonstrate (1) considerable inter-individual variability in the congener-specific metabolism of PCBs to OH-PCBs; (2) the enantioselective formation of OH-PCBs by human CYP2A6, CYP2B6, and CYP2E1; and (3) that chiral PCB metabolites are formed enantioselectively from prochiral PCB congeners. Interestingly, the metabolism of PCBs by CYP2A6 appears to involve arene oxide intermediates, as suggested by the formation of 1,2-shift products as major metabolites of PCB 91 and PCB 132. In contrast, 1,2-shift products are minor PCB metabolites formed in rodents. Therefore extrapolation of hepatic metabolism across species may not be consistent and these differences should be considered in future toxicity and risk assessment studies.

In work entitled CHANGE, I return in my memories to my home region, a town where I have lived and lived most of my life and which has been nicknamed the "Triangle of Death" for decades. This time period has had and continues to have a significant impact on my existence. In the first phase of the timeline of creating the topic of the diploma thesis, are my returns through induction and deduction. I approach my father's illness, which is not uncommon in my homeland. I connect connections leading to finding out the causes of origin and occurrence. Subsequently, I recall memories related to the stories heard from people about the factory, which was supposed to be and perhaps was the livelihood for the inhabitants of the poor eastern Slovakia, as well as the production of PCBs. I create, compile and depict images hidden in the memory of moments from my lived childhood. I depict the Chemko Strážske factory, which at that time was a kind of illusion of a happy life. I am looking for a way of acceptance and ways of reconciliation using painting techniques, through the representation of symbols and the central characters that represent it all.

Acylation of cyclohexene can provide number of reaction products. Cyclohexene, 1-methylcyclohexene and 3-methylcyclohexene were acylated with propionic anhydride over diferent zeolite structures and molecular sieves. Cyclohexene acylation led to propionylcyclohexene. The major acylation products of 1-methylcyclohexene is 2-methyl-3-propionylcyclohexene. Reaction product of 3-methylcyclohexene acylation is 4-methyl-3-propionylcyklohexene and 3-methyl-2-propionylcyclohexene. The aim of acylation biphenyl with carboxylic acid anhydrides and chlorides was to prove reaction with the highest conversion of substrate. The highest biphenyl conversion was obtained with octanoyl chloride and hexanoic anhydride over zeolite USY (15). The highest selectivity to 4-acylbiphenyl was observed.

No description available.

As technology advances, a need for non-metal, conductive materials has arisen for several types of applications. Lithographic techniques are helpful to develop some of these applications. Such techniques require materials that are insulating and become conductive after irradiated. Composites of polyaniline in its emeraldine base form (PANI-EB) doped with photo-acid generators (PAG) become conductive upon photo-irradiation. This increase in conductivity is due to the protonation of PANI-EB. Such materials may be utilized to fabricate conducting patterns by photo-irradiation; however, the conductivity obtained by direct irradiation of PANI-EB/PAG composites is normally quite low (<10-3 S/cm) due to aggregation of highly loaded PAG. In this work, poly(ethylene glycol) (PEG), a proton transfer polymer, was added to PANI-EB/PAG. Results showed the addition of low molecular weight (MW) (550) PEG significantly enhanced the photo-induced conductivity to a level comparable to that of PANI-salt synthesized by oxidizing aniline in the presence of an acid. High MW (8000) PEG is less effective than PEG 550, and composites of PANI-EB and N-PEG-PANI showed conductivity as high as 102 S/cm after treatment with HCl vapor. The photo-induced conductivity of the N-PEG-PANI/PANI-EB/PAG composite reached 10-2-10-1 S/cm. Polychlorinated biphenyls (PCBs) are a class of chemicals with 209 different congeners, some of which are known carcinogens, and are persistent organic pollutants in the environment. After its synthesis, it was seen as a phenomenal additive in a multitude of different applications leading to the wide spread use of PCBs and a need for a safe, effective, and inexpensive remediation technique. While it is known that magnesium can degrade PCBs, the mechanism of this reaction was not well-understood. In order for magnesium to be broadly used as a remediation tool, it is necessary to fully understand how the reaction is taking place and if the PCBs are able to be fully dechlorinated into biphenyl. This research focuses on the hydrodechlorination of PCBs with zero-valent magnesium in acidified ethanol. The degradation pathways of 2, 2', 3, 5, 5', 6- hexachlorobiphenyl were investigated to determine the identity of the daughter PCBs produced, how and if they continue to be dechlorinated into biphenyl. The proton source for this hydrodehalogenation reaction was also studied using both deuterated solvent and acid to give more detail to the mechanism of this reaction.