published_or_final_version / abstract / Civil Engineering / Doctoral / Doctor of Philosophy

The viscosity and density of bis(8-methylnonyl) benzene-1,2- dicarboxylate {diisodecyl phthalate (DIDP)}, with a nominal viscosity at T = 298 K and p = 0.1 MPa of 87 mPa•s, have been measured at temperatures from (298.15 to 423.15) K and pressures from (0.1 to 70) MPa. A vibrating wire viscometer, with a wire diameter of about 0.15 mm, was utilised for the viscosity measurements and the results have an expanded uncertainty, (k = 2), including the error arising from the pressure measurement, of between ±(2 and 2.5) % The density was determined with two vibrating tube densimeters one for operation at p≈0.1 MPa with an expanded uncertainty (k = 2) of about ±0.1 %, the other that used at pressures up to 70 MPa, with an estimated expanded uncertainty (k = 2) of about ±0.3 %. Measurements of density and viscosity were performed on three samples of DIDP each with different purity stated by the supplier and as a function of water mass fraction. The measured viscosity and density are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with the expanded (k = 2) uncertainties. The obtained viscosities at p = 0.1 MPa agree with values reported in the literature within the combined expanded (k = 2) uncertainties of the measurements while our densities differ by no more than 1.5 %. Viscosity data at p > 0.1 MPa deviate systematically from the literature values in the range of -10 % to 10 %. An apparatus capable of simultaneously measuring the solubility of a gas dissolved in a liquid and the viscosity and the density of the resulting mixture over a wide temperature and pressure range was constructed and tested. Preliminary results have been reported.

Orientador: Samuel Monroe Cohen / Resumo: O aumento da incidência de distúrbios testiculares e a possível influência de substâncias químicas ambientais, como o dibutilftalato (DBP) e a acrilamida (AA), exigem a identificação de modos de ação. A maioria dos estudos de toxicologia reprodutiva utiliza amostras de RNA provenientes de todo o testículo para avaliar a expressão genica; entretanto, análises de tipos celulares isolados poderiam gerar resultados mais específicos. Entre as células germinativas testiculares, as espermatogônias são importantes pois representam o início da espermatogênese. Este estudo objetivou, 1) estabelecer técnica de isolamento de espermatogônias; 2) aplicar esta técnica para verificar possíveis alterações na expressão gênica (Pou5f1, Kitlg, Mki-67, Bak1 e Spry4) em testículos de ratos pré-púberes (DPN24) e púberes (DPN45) após exposição in utero e pós-natal ao DBP ou à AA. A técnica foi eficiente para o isolamento das espermatogônias. A exposição ao DBP levou à redução do peso corporal da ninhada ao nascer, da distância anogenital dos filhotes machos no DPN4 e ao aumento da frequência de retenção de mamilos no DPN14. Os pesos relativos dos testículos expostos ao DBP estavam reduzidos apenas no DPN24. Animais expostos ao DBP mostraram níveis reduzidos de expressão de Pou5f1 e Mki67 no DPN24, e de Pou5f1 e Spry4 no DPN45. A exposição a AA reduziu a expressão de Pou5f1, Mki67 e Spry4, embora não significativamente. Nossos resultados sugerem que DBP atue reduzindo a proliferação celular e prejudi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The increased incidence of testicular disorders in young men and the possible influence of environmental chemicals, such as dibutyl phthalate (DBP) and acrylamide (AA), requires experimental models for identifying modes of action. Most published reproductive toxicologic studies use RNA samples from the total testis to evaluate testicular gene expression; however, analyses of isolated cell types could provide a more specific tool. Among testicular germ cells, spermatogonia are critical since they represent the onset of spermatogenesis. This study aimed, 1) to establish a technique for spermatogonia isolation; 2) to apply this isolation technique to verify possible gene expression alterations (Pou5f1, Kitlg, Mki-67, Bak1 and Spry4) in prepubertal post-natal day, (PND24) and pubertal (PND45) testes after in utero and postnatal exposure to DBP or AA. The technique was efficient for isolation of a majority of spermatogonia. In utero DBP exposure led to reduced litter body weight at birth, reduced anogenital distance of male pups on PND4, and increased frequency of male nipple retention on PND14 compared to controls. DBP-exposed relative testes weights were reduced only at PND24 compared to control but they did not differ at PND45. DBP-exposed animals showed reduced expression levels of Pou5f1 and Mki67 on PND24, and reduced expression of Pou5f1 and Spry4 on PND45. AA exposure reduced expression of Pou5f1, Mki67 and Spry4 at PND45 although not significantly. Our results suggest tha... (Complete abstract click electronic access below) / Doutor

A three-compartment model is extended to estimate the fate and transport of DEHP in a realistic residential environment. The model considered eight environmental media (i.e. air, particulate matter with six size fractions, vinyl flooring, carpet, furniture, dust, wall and ceiling). Particle movement (deposition and resuspension), dust removal (vacuuming), indoor cooking, and adsorption/absorption on indoor surfaces are included. The predicted airborne DEHP concentrations at steady state are within 0.1 [microgram]/m³ to 0.6 [microgram]/m³, which are similar to those measured in field studies. After vinyl flooring (the primary source) is removed, it takes 2 years for the indoor airborne DEHP level to reduce 0.01 [microgram]/m³, and the time increases significantly when carpet present. The results indicate that carpets as well as other interior surfaces may be important phthalate sinks and if the only removal mechanism is ventilation, strongly sorbing phthalate may persist for years. Phthalate amount in dust is strongly influenced by the deposition surface. The concentration of DEHP presents 10 times higher in dust on the source (vinyl flooring) than on the sink (furniture), and it takes more than a year for DEHP to reach equilibrium between bulk air and dust. The domestic activity of cooking is then included in the model and it shows that suspended particle concentration has a substantial impact on gas-phase DEHP level indoors, while the influence of ventilation is only to some extent. Three other SVOCs (DMP, BBP and DiDP) are also investigated and their environmental fates show that chemical’s vapour pressure and octanol/air partition coefficient have substantial influences on sorbing mechanisms and the gas phase and airborne concentrations. / text

The viscosity and density of bis(8-methylnonyl) benzene-1,2- dicarboxylate {diisodecyl phthalate (DIDP)}, with a nominal viscosity at T = 298 K and p = 0.1 MPa of 87 mPa•s, have been measured at temperatures from (298.15 to 423.15) K and pressures from (0.1 to 70) MPa. A vibrating wire viscometer, with a wire diameter of about 0.15 mm, was utilised for the viscosity measurements and the results have an expanded uncertainty, (k = 2), including the error arising from the pressure measurement, of between ±(2 and 2.5) % The density was determined with two vibrating tube densimeters one for operation at p≈0.1 MPa with an expanded uncertainty (k = 2) of about ±0.1 %, the other that used at pressures up to 70 MPa, with an estimated expanded uncertainty (k = 2) of about ±0.3 %. Measurements of density and viscosity were performed on three samples of DIDP each with different purity stated by the supplier and as a function of water mass fraction. The measured viscosity and density are represented by interpolating expressions with differences between the experimental and calculated values that are comparable with the expanded (k = 2) uncertainties. The obtained viscosities at p = 0.1 MPa agree with values reported in the literature within the combined expanded (k = 2) uncertainties of the measurements while our densities differ by no more than 1.5 %. Viscosity data at p > 0.1 MPa deviate systematically from the literature values in the range of -10 % to 10 %. An apparatus capable of simultaneously measuring the solubility of a gas dissolved in a liquid and the viscosity and the density of the resulting mixture over a wide temperature and pressure range was constructed and tested. Preliminary results have been reported.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on October 16, 2007) Vita. Includes bibliographical references.

Background: Emerging evidence from animals indicates that oxidative stress plays a crucial role in the effects of phthalate exposure on male reproductive dysfunctions, which has never been thoroughly explored in humans. Objective: To explore the potential mediating role of oxidative stress in the association of phthalate exposure with semen quality among 1034 Chinese men. Method: Repeated urine samples gathered from the male partners of sub-fertile couples were analyzed for 3 oxidative stress markers [8-hydroxy-2-deoxyguanosine (8-OHdG), 8-iso-prostaglandin F2α (8-isoPGF2α) and 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA)], using a liquid chromatography-tandem mass spectrometry. Multivariate regression models were constructed to evaluate the associations of urinary oxidative stress markers with urinary phthalate metabolites and semen quality. We also explored the potential mediation effects by oxidative stress markers. Results: Significantly positive dose-dependent relationships were observed between each individual phthalate metabolite and all analyzed oxidative stress markers (all p for trend<0.05), except for monoethyl phthalate (MEP) in relation to HNE-MA. Additionally, significantly or suggestively inverse dose-dependent relationships were exhibited between urinary 8-isoPGF2α and sperm concentration (p for trend = 0.05), and between urinary 8-OHdG and percent of normal sperm morphology (p for trend = 0.01). Mediation analysis showed that urinary 8-isoPGF2α suggestively mediated 12% of the inverse association between monobutyl phthalate (MBP) and sperm concentration, and that urinary 8-OHdG suggestively mediated 32% of the inverse association of MEP with percent of normal sperm morphology (both p < 0.10). Conclusions: Although further investigations are required, our results suggest that oxidative stress may play a mediating role in the effects of phthalate exposure on impaired semen quality.

No description available.

Secular trends in breast cancer incidence in younger women suggest environmental factors, like exposure to environmental chemicals, may play a role in rising incidence. One of the strongest risk factors for developing breast cancer, next to family history, is high mammographic breast density, which is defined as the proportion of fibroglandular breast tissue relative to fat as seen on a mammogram. Phthalates, a ubiquitous endocrine disrupting chemical, have the potential to interfere with endogenous hormones like estrogen and androgens. There is growing evidence from animal and epidemiologic studies indicating distinct periods of heightened susceptibility to endocrine disrupting chemicals throughout the life course, particularly during critical windows of breast development. Exposure to hormonally active environmental chemicals like phthalates may be a modifiable risk factor for breast cancer, therefore reducing or eliminating exposure could have substantial public health benefits. The overarching goal of this dissertation was to assess the relationship between exposure to phthalates during two critical windows of susceptibility, the prenatal and pregnancy periods, and its effect on breast tissue composition in adolescence and adulthood. First, a comprehensive review of epidemiologic studies summarized the body of evidence for the association between phthalate exposure and intermediate markers known to be in the causal pathway of breast cancer risk (age at breast development, menarche, and breast tissue composition). This systematic review of the literature aimed to identify potential patterns of evidence by outcome and timing of exposure. Evidence from this review suggested that phthalate exposure during the prenatal and childhood periods may play a role in altering menarche. Findings for phthalate exposure and age at breast development were inconclusive. There was a considerable lack of epidemiologic data on phthalate exposure and breast tissue composition throughout the life course. Based on one study, there is a potential association between phthalate exposure during pre-puberty and altered breast tissue density in adolescent girls. No study assessed the relationship between phthalate exposure during the prenatal or pregnancy period and subsequent breast tissue composition. Second, an examination for the association between prenatal phthalate exposure and breast tissue composition measured in adolescence (Chapter 3) and the association between phthalate exposure during pregnancy and breast tissue composition measured during or after the postpartum transient period (Chapter 4) aimed to address this major gap identified from the comprehensive review. The empirical chapters of this dissertation used data from an ongoing longitudinal birth cohort study of mothers and their children conducted by the New York City Columbia Center for Children's Environmental Health and the Breast Cancer and the Environment Research Project (CCCEH-BCERP). The CCCEH-BCERP study cohort has prospective data on nine phthalate metabolite concentrations measured during the third trimester of pregnancy and breast tissue composition measured in a subsample of mother-daughter dyads. Notably, we used novel non-invasive methods (optical breast spectroscopy) in this younger cohort of mothers and daughters to objectively measure specific components of the bulk breast composition before mammography screening age. There was significant evidence of altered breast tissue composition in both mothers and daughters. For daughters (n=127, mean age 15.2 ± 1.9 years), prenatal exposures to select low molecular weight (LMW) and high molecular weight (HMW) phthalate metabolites altered overall breast density in opposing directions, which appears to be driven by significant altered percent breast water. There was a significant association between higher prenatal levels of a LMW phthalate metabolite (monobutyl phthalate) and lower levels of overall breast density (adjusted β = -0.32; 95% CI: -0.51, -0.13) and significant association between sum of di(2-ethylhexyl) phthalate (∑DEHP), a HMW phthalate metabolite, and higher levels of overall breast density in girls (adjusted β = 0.20; 95% CI: 0.05, 0.34). For mothers (n=133, mean age 41 ± 5.3 years at follow-up), there was a significant association between two LMW phthalate metabolites and lower levels of percent breast collagen. Additionally, there was a significant inverse relationship between levels of mono-(3-carboxypropyl), a HMW phthalate metabolite, and percent total hemoglobin of the breast (adjusted β =-0.03; 95% CI: -0.06, 0.00, p=0.05). Overall, this dissertation increased our understanding of the impact that exposure to phthalates during critical windows of susceptibility may have on specific components of the breast. Reducing exposure to both HMW and LMW phthalates may have an impact in reducing breast cancer risk, particularly for girls prenatally exposed, as there was stronger evidence of higher overall breast density and percent water from exposure to select HMW phthalates. Future prospective studies should confirm these results as findings might provide an opportunity for modifying potential breast cancer risk.

by Chan Hiu-wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 123-133). / Text in English; abstracts in English and Chinese. / by Chan Hiu-wai. / Acknowledgements --- p.i / Abstract --- p.ii / List of Figures --- p.x / List of Tables --- p.xiii / List of Abbreviations --- p.xv / Page / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The chemical class: Phthalate esters --- p.1 / Chapter 1.2 --- Di(2-ethylhexyl)phthalate --- p.2 / Chapter 1.2.1 --- Characteristics of DEHP --- p.5 / Chapter 1.2.2 --- Production and applications --- p.5 / Chapter 1.2.3 --- Environmental releases and environmental fate --- p.8 / Chapter 1.2.4 --- Toxicity of DEHP --- p.8 / Chapter 1.2.4.1 --- Mammalian toxicity --- p.9 / Chapter 1.2.4.2 --- Toxicity to aquatic organisms --- p.10 / Chapter 1.2.5 --- Regulations --- p.10 / Chapter 1.3 --- Conventional technologies for DEHP removal --- p.11 / Chapter 1.3.1 --- Biodegradation --- p.11 / Chapter 1.3.2 --- Coagulation --- p.11 / Chapter 1.3.3 --- Adsorption --- p.11 / Chapter 1.4 --- Innovative technologies for DEHP removal --- p.12 / Chapter 1.4.1 --- Biosorption --- p.13 / Chapter 1.4.1.1 --- Definition of biosorption --- p.13 / Chapter 1.4.1.2 --- Mechanisms --- p.13 / Chapter 1.4.1.3 --- Selection of biosorbents --- p.17 / Chapter 1.4.1.4 --- Assessment of biosorption performance --- p.21 / Chapter a. --- Batch adsorption experiments --- p.21 / Chapter b. --- Modeling of biosorption --- p.21 / Chapter 1.4.1.5 --- Recovery of biosorbents --- p.23 / Chapter 1.4.1.6 --- Development of biosorption process --- p.23 / Chapter 1.4.1.7 --- Seaweeds as biosorbents --- p.24 / Chapter 1.4.2 --- Advanced oxidation processes --- p.27 / Chapter 1.4.3 --- Heterogeneous photocatalytic oxidation --- p.30 / Chapter 1.4.3.1 --- Photocatalyst --- p.30 / Chapter 1.4.3.2 --- General mechanisms --- p.31 / Chapter 1.4.3.3 --- Influencing parameters in PCO --- p.33 / Chapter 1.4.3.4 --- Enhanced performance by addition of hydrogen peroxide --- p.33 / Chapter 2 --- Objectives --- p.36 / Chapter 3 --- Materials and Methods --- p.38 / Chapter 3.1 --- Chemical reagents --- p.38 / Chapter 3.2 --- Biosorption of DEHP by seaweed biomass --- p.39 / Chapter 3.2.1 --- Biosorbents --- p.39 / Chapter 3.2.2 --- Determination method of DEHP --- p.39 / Chapter 3.2.3 --- Batch adsorption experiments --- p.44 / Chapter 3.2.3.1 --- Screening of potential biomass --- p.44 / Chapter 3.2.3.2 --- Characterization of beached seaweed and S. siliquastrum --- p.44 / Chapter a. --- Total organic carbon (TOC) content --- p.44 / Chapter b. --- Leaching of biomass components --- p.45 / Chapter 3.2.3.3 --- Combined effect of pH and biomass concentration --- p.45 / Chapter 3.2.3.4 --- Effect of retention time --- p.45 / Chapter 3.2.3.5 --- Effect of agitation rate --- p.45 / Chapter 3.2.3.6 --- Effect of temperature --- p.46 / Chapter 3.2.3.7 --- Effect of particle size --- p.46 / Chapter 3.2.3.8 --- Effect of DEHP concentration --- p.46 / Chapter 3.2.4 --- Recovery of adsorbed DEHP from seaweed biomass --- p.47 / Chapter 3.2.4.1 --- Screening for suitable desorbing agents --- p.47 / Chapter 3.2.4.2 --- Multiple adsorption-desorption cycles --- p.47 / Chapter 3.2.5 --- Statistical analysis --- p.43 / Chapter 3.3 --- Photocatalytic oxidation --- p.48 / Chapter 3.3.1 --- Photocatalytic reactor --- p.48 / Chapter 3.3.2 --- Optimization of reaction conditions --- p.48 / Chapter 3.3.2.1 --- Effect of reaction time --- p.48 / Chapter 3.3.2.2 --- Effect of initial pH --- p.51 / Chapter 3.3.2.3 --- Effect of Ti02 concentration --- p.51 / Chapter 3.3.2.4 --- Effect of UV intensity --- p.52 / Chapter 3.3.2.5 --- Effect of H202 concentration --- p.52 / Chapter 3.3.2.6 --- Effect of initial DEHP concentration and irradiation time --- p.52 / Chapter 3.3.2.7 --- Statistical analysis --- p.52 / Chapter 3.3.4 --- Determination of mineralization of DEHP by analyzing total Organic carbon (TOC) content --- p.53 / Chapter 3.3.5 --- Identification of intermediate products of DEHP --- p.53 / Chapter 3.3.6 --- Evaluation for the toxicity of DEHP and intermediate products --- p.53 / Chapter 3.3.6.1 --- Microtox® test --- p.53 / Chapter 3.3.6.2 --- Amphipod survival test --- p.55 / Chapter 3.4 --- Feasibility of combining biosorption and photocatalyic oxidation as an Integrated treatment for DEHP --- p.57 / Chapter 3.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.57 / Chapter 3.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.57 / Chapter 4 --- Results --- p.58 / Chapter 4.1 --- Determination method of DEHP --- p.58 / Chapter 4.2 --- Biosorption --- p.58 / Chapter 4.2.1 --- Batch adsorption experiments --- p.58 / Chapter 4.2.1.1 --- Screening of potential biomass --- p.58 / Chapter 4.2.1.2 --- Characterization of beached seaweed and S. siliquastrum --- p.61 / Chapter a. --- Total organic carbon (TOC) content --- p.61 / Chapter b. --- Leaching properties --- p.61 / Chapter 4.2.1.3 --- Combined effect of pH and biomass concentration --- p.61 / Chapter 4.2.1.4 --- Effect of retention time --- p.74 / Chapter 4.2.1.5 --- Effect of agitation rate --- p.74 / Chapter 4.2.1.6 --- Effect of temperature --- p.74 / Chapter 4.2.1.7 --- Effect of particle size --- p.74 / Chapter 4.2.1.8 --- Effect of initial DEHP concentration: Modeling by Langmuir and Freundlich adsorptin isotherm --- p.79 / Chapter 4.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.84 / Chapter 4.2.2.1 --- Screening for suitable desorbing agents --- p.84 / Chapter 4.2.2.2 --- Multiple adsorption-desorption cycles --- p.84 / Chapter 4.3 --- Photocatalytic oxidation --- p.90 / Chapter 4.3.1 --- Optimization of reaction conditions --- p.90 / Chapter 4.3.1.1 --- Effect of reaction time --- p.90 / Chapter 4.3.1.2 --- Effect of initial pH --- p.90 / Chapter 4.3.1.3 --- Effect of TiO2 concentration --- p.90 / Chapter 4.3.1.4 --- Effect of UV intensity --- p.90 / Chapter 4.3.1.5 --- Effect of H2O2 concentration --- p.95 / Chapter 4.3.1.6 --- Effect of initial DEHP and irradiation time --- p.95 / Chapter 4.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.95 / Chapter 4.3.3 --- Identification of intermediate products of DEHP --- p.95 / Chapter 4.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.102 / Chapter 4.3.4.1 --- Microtox® test --- p.102 / Chapter 4.3.4.2 --- Amphipod survival test --- p.102 / Chapter 4.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.102 / Chapter 4.4.1 --- Effect of algal extract on photocatalytic oxidation of DEHP --- p.102 / Chapter 4.4.2 --- Determination of mineralization of algal extract by analyzing total organic carbon (TOC) --- p.103 / Chapter 5 --- Discussion --- p.108 / Chapter 5.1 --- Determination method of DEHP --- p.108 / Chapter 5.2 --- Biosorption --- p.108 / Chapter 5.2.1 --- Batch adsorption experiments --- p.108 / Chapter 5.2.1.1 --- Screening of potential biomass --- p.108 / Chapter 5.2.1.2 --- Characteristic of S. siliquastrum and beached seaweed --- p.109 / Chapter 5.2.1.3 --- Combined effect of pH and biomass concentration --- p.109 / Chapter 5.2.1.4 --- Effect of retention time --- p.111 / Chapter 5.2.1.5 --- Effect of agitation rate --- p.111 / Chapter 5.2.1.6 --- Effect of temperature --- p.111 / Chapter 5.2.1.7 --- Effect of particle size --- p.112 / Chapter 5.2.1.8 --- Effect of initial DEHP concentration: Modeling of Langmuir and Freundlich adsorption isotherms --- p.112 / Chapter 5.2.2 --- Recovery of adsorbed DEHP by seaweed biomass --- p.114 / Chapter 5.2.2.1 --- Screening for suitable desorbing agents --- p.114 / Chapter 5.2.2.2 --- Multiple adsorption-desorption cycles --- p.115 / Chapter 5.3 --- Photocatalytic oxidation --- p.115 / Chapter 5.3.1 --- Optimization of reaction conditions --- p.115 / Chapter 5.3.1.1 --- Effect of reaction time --- p.115 / Chapter 5.3.1.2 --- Effect of pH --- p.116 / Chapter 5.3.1.3 --- Effect of TiO2 concentration --- p.116 / Chapter 5.3.1.4 --- Effect of UV intensity --- p.116 / Chapter 5.3.1.5 --- Effect of H2O2 concentration --- p.117 / Chapter 5.3.1.6 --- Effect of DEHP concentration and irradiation time --- p.117 / Chapter 5.3.2 --- Determination of mineralization of DEHP by analyzing total organic carbon (TOC) --- p.117 / Chapter 5.3.3 --- Identification of intermediate products of DEHP --- p.118 / Chapter 5.3.4 --- Evaluation for the toxicity of DEHP and the intermediate products --- p.119 / Chapter 5.4 --- Feasibility of combining biosorption and photocatalytic oxidation as an integrated treatment for DEHP --- p.119 / Chapter 6 --- Conclusions --- p.121 / Chapter 7 --- References --- p.123