The tumor suppressor p53 has a close relation with reactive oxygen species (ROS). As an indispensable component of the cellular redox system, ROS not only have been established to be involved in p53-dependent apoptosis, but also regulate p53 activity. Recent studies revealed several novel actions of p53, such as transactivation of antioxidative proteins, mitochondria translocation and inhibition of glycolysis. The fate of cells where p53 signaling pathways are initiated is either survival or death. In this review, we examine the hypothesis that ROS regulate cell fate through p53, in a way that physiological ROS levels trigger the protective pathways, while p53 behaves more like a cell killer under cytotoxic oxidative stress.

Xenobiotic Organic Compounds (XOCs) are present in wastewater and wastewater-impacted environmental systems. Pharmaceuticals and personal care products are a broad and varied category of chemicals that are included among these compounds. Although, these compounds have been detected at low levels in surface water, concerns that these compounds may have an impact on human health and aquatic life, have led to increased interest in how XOCs are removed during wastewater treatment. Recognizing specific mechanisms in recent literature and simulating those mechanisms responsible for the removal of XOCs is the main objective of this study. Conventional models, such as the popular activated sludge models (ASM1, ASM2, etc), do not sufficiently address the removal processes; therefore, a fate model is created to provide a means of predicting and simulating removal mechanisms along with experimental analyses. GPS-X is a multi-purpose modeling tool for the simulation of municipal and industrial wastewater treatment plants. This software package includes conventional models as built-in libraries, which can be used as bases on which new models can be created. In this thesis, the removal mechanisms of XOCs are recognized and investigated; a new library for GPS-X is also created to include XOCs. As a first step the uncalibrated fate model, which includes all mechanisms of interest with their process rates and state variables, is developed using in GPS-X software. A modified ASM1 (Mantis model) is used as a basis for developing the fate model. Since only a group of mechanisms is responsible for the removal of each compound the mechanisms are categorized in three different case studies as the next step. Thus, one submodel is associated with each case study. The model developer toolbar in GPS-X software is used to develop the model for these case studies. The first case study involves the removal of antibiotics, such as Sulfamethoxazole. The removal mechanisms used in this case are biodegradation, sorption, and parent compound formation, with co-metabolism and competitive inhibition effects being inserted into the structure of the model. Secondly, the removal of nonylphenol ethoxylates (NPEOs) occurs through abiotic oxidative cleavage, hydrolysis, and biodegradation. The third case study includes removal mechanisms of biodegradation and sorption for neutral and ionized compounds. In the calibration process, model parameters are tuned such that the model can best simulate the experimental data using optimization methods. A common error criterion is Sum of Squared Errors (SSE) between the simulated results and the measured data. By minimizing SSE, optimal values of parameters of interest can be estimated. In each case study different data sets were used for the validation process. To validate the calibrated model, simulated results are compared against experimental data in each case study. The experimental data set used in the validation process is different from that used for calibrating the model, which means the validation process data set was obtained from the different literature. By looking at the validation results, it is concluded that the proposed model successfully simulates removal of XOCs. Since the operating parameters of wastewater treatment plants, such as Solids Retention Time (SRT) and Hydraulic Retention Time (HRT) are crucial for the fate of XOC???s, a sensitivity analysis is carried out to investigate the effect of those parameters. Moreover, the pH effect is studied because it relates to the ionized XOCs. Sensitivity analysis results show that the fate model is more sensitive to model parameters i.e. biodegradation rate constant (kb) than the operational parameters, i.e. SRT and HRT. Furthermore, the responses showed sensitivity to pH, whereby acidic conditions provide a better environment for removing neutral forms and alkaline conditions were suitable for removing ionized forms, according to the ionized compound fate model.

This essay aims to investigate the role of fate in the Apocryphon of John – an issue which, with a few exceptions, has been surprisingly overlooked by modern scholarship. In the few modern publications available on the subject, the concept of fate has previously solely been examined in the light of the Greek Philosophical schools, often neglecting texts from a Jewish-Hellenistic context.  Here it is argued that the depiction of fate in the Apocryphon of John, as well as the dualism between Pronoia – the providence of god – and its negative counterpart, the imitating spirit, is closely related to Jewish speculations about external influence and free will in literature such as the Testaments of the Twelve Patriarchs and the Community Rule from the Dead Sea Scrolls. Furthermore, it is argued that the author – much like Philo of Alexandria - presents Pronoia – the providence of god - as an extension of God, a concept which preserves his transcendence and at the same time allows him to intervene in earthly activities. Similarly, the imitating spirit, which is also presented as identical to fate, works as an extension of the demiurge. As a result of this reading of the text, the dualism between God’s providential activities carried out by Pronoia and the influence of fate over mankind, carried out by the imitating spirit, becomes more evident and radical. It has recently been argued that the discourse of enslavement under fate only was applied to “the other” and that it was used primarily to draw boundary demarcations between the own group and the ones outside it. In this essay, I go against this hypothesis and suggest that the threat of enslavement under fate primarily appears in conjunction with paraenetic discourse and is used to exhort the followers to emulate a certain behavior.

<p>The study and application of materials possessing size dimensions in the nano scale range and, as a result, unique properties have led to the birth of a new field; nanotechnology. Scientists and engineers have discovered and are exploiting the novel physicochemical characteristics of nanoparticles (NPs) to enhance consumer products and technologies in ways superior to their bulk counterparts. Escalating production and use of NPs will unavoidably lead to release and exposure to environmental systems. This introduction of emerging potential contaminant NPs will provide new and interesting challenges for exposure and risk forecasting as well as environmental endurance.</p><p>The ultimate goal of this research is to develop a framework that incorporates experimental and computational efforts to assess and better understand the exposure of metal and metal-oxide NPs released to wastewater treatment plants (WWTPs) and further implications on land application units (LAUs) where biosolids can be applied. The foundation of the computational effort is comprised of Monte Carlo mass balance models that account for the unique processes affecting NP fate and transport through the different technical compartments of a WWTP and LAU. Functional assay and bioreactor experiments in environmental media were used to determine parameters capable of describing the critical processes that impact the fate of NPs in wastewater. </p><p>The results of this research indicate that a simplified, but still environmentally relevant nano-specific exposure assessment is possible through experimentation to parameterize adapted models. Black box modeling efforts, which have been shown in previous studies, show no disadvantage relative to discretization of technical compartments as long as all key transport and fate mechanisms are considered. The distribution coefficient (_), an experimentally determined, time-dependent parameter, can be used to predict the distribution of NPs between the liquid and solid phase in WWTPs. In addition, this parameter can be utilized a step further for the estimation of the more fundamental, time independent attachment efficiency between the NPs and the solids in wastewater. The NP core, size, and surface coating will influence the value of these parameters in addition to the background particle characteristics as the parameters are specific to the environmental system of study. For the metal and metal-oxide NPs studied, preferential overall association of approximately 90% or greater with the solid phase of wastewater was observed and predicted. </p><p>Furthermore, NP transformations including dissolution, redox reactions, and adsorption can potentially impact exposure. For example, experimental results showed that nano-CeO2 is reduced from Ce(IV) to Ce(III) when in contact with wastewater bacteria where Ce2S3 will likely govern the Ce(III) phase in biosolids. From the literature, similar transformations have been observed with Ag and ZnO NPs to Ag2S and ZnS. With respect to TiO2 NPs, studies indicated that due to high insolubility, these NPs would not undergo transformation in WWTPs. The distribution and transformation rate coefficients can then be used in fate models to predict the NP species exposed to aquatic and terrestrial systems and environmentally relevant concentrations released from WWTPs. </p><p>Upon completion of the WWTP model, the predicted concentrations of NPs and NP transformation byproducts released in effluent and biosolids were attainable. A simple mass balance model for NP fate in LAUs was then developed to use this output. Results indicate that NP loading on LAUs would be very low but that build up over time to steady state could result in mass concentrations on the order of the typical level for the background metal in soil. Transport processes of plant uptake and leaching were expected to greatly impact the solid phase concentration of the NPs remaining in the LAU, while rainfall did not impart a significant influence upon variation between low and high annual amounts. The significance of this research is the introduction of a method for NP exposure assessment in WWTPs and subsequently in LAUs. This work describes and quantifies the key processes that will impact Ag, TiO2, CeO2 and ZnO NP fate and transport, which can inform future studies, the modeling community and regulatory agencies.</p> / Dissertation

No description available.

Cities are sources of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), to surrounding regions and beyond. A spatially resolved, (5×5 km2), dynamic contaminant fate model named Spatially Oriented or SO-MUM was developed by coupling the fugacity based Multimedia Urban Model (MUM) (Diamond et al., 2001; Diamond et al., 2010c) and the Boundary Layer Forecast Model and Air Pollution Prediction System (BLFMAPS) which was developed at Environment Canada (Daggupaty et al., 2006). MUM was updated to contain a revised surface film sub-model which takes into account the dynamic nature of surface films. SO-MUM was illustrated by application to the City of Toronto, Canada. Spatially resolved air emissions of Σ88PCB were estimated to be ~230 (40-480) kg y-1, 280 (50-580) g y-1 km-2, and 90 (16-190) mg y-1 capita-1 and Σ26PBDE were estimated to be 28 (6-63) kg y-1, 34 (7-77) g y-1 km-2 and 11 (2-25) mg y-1 capita-1. These emissions were back-calculated from measured air concentrations and spatial chemical mass inventories yielding emission rates per mass inventory of 0.4 (0.05-1.6) and 0.1 (0.01-0.7) g kg-1inventory y-1, for Σ88PCBs and Σ26PBDEs, respectively. Approximately 30% and 16% of PCB and PBDE emissions emanate from the city’s downtown. Air advection accounted for ~95% (PCB) and ~70% (PBDE) of total air emission losses with the remaining balance depositing to the city. The metric “Urban Travel Distance” or UTD was introduced for quantifying the extent of an urban plume resulting from spatially heterogeneous emissions. For PCBs and PBDEs the UTDs were ~25 and ~30 km. The updated surface film sub-model indicated that films “bounce” higher vapor pressure semi-volatile organic compounds (SVOCs) back into the air but they act as a transient sink from air for lower vapor pressure SVOCs, thereby facilitating transport to surface waters. Model calculations suggest that if the PCB inventory is reduced, volatilization from near-shore Lake Ontario will become a net source of PCBs to air, but that neither near-shore Lake Ontario nor soil would become a significant volatilization PBDE source to air.

Cities are sources of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), to surrounding regions and beyond. A spatially resolved, (5×5 km2), dynamic contaminant fate model named Spatially Oriented or SO-MUM was developed by coupling the fugacity based Multimedia Urban Model (MUM) (Diamond et al., 2001; Diamond et al., 2010c) and the Boundary Layer Forecast Model and Air Pollution Prediction System (BLFMAPS) which was developed at Environment Canada (Daggupaty et al., 2006). MUM was updated to contain a revised surface film sub-model which takes into account the dynamic nature of surface films. SO-MUM was illustrated by application to the City of Toronto, Canada. Spatially resolved air emissions of Σ88PCB were estimated to be ~230 (40-480) kg y-1, 280 (50-580) g y-1 km-2, and 90 (16-190) mg y-1 capita-1 and Σ26PBDE were estimated to be 28 (6-63) kg y-1, 34 (7-77) g y-1 km-2 and 11 (2-25) mg y-1 capita-1. These emissions were back-calculated from measured air concentrations and spatial chemical mass inventories yielding emission rates per mass inventory of 0.4 (0.05-1.6) and 0.1 (0.01-0.7) g kg-1inventory y-1, for Σ88PCBs and Σ26PBDEs, respectively. Approximately 30% and 16% of PCB and PBDE emissions emanate from the city’s downtown. Air advection accounted for ~95% (PCB) and ~70% (PBDE) of total air emission losses with the remaining balance depositing to the city. The metric “Urban Travel Distance” or UTD was introduced for quantifying the extent of an urban plume resulting from spatially heterogeneous emissions. For PCBs and PBDEs the UTDs were ~25 and ~30 km. The updated surface film sub-model indicated that films “bounce” higher vapor pressure semi-volatile organic compounds (SVOCs) back into the air but they act as a transient sink from air for lower vapor pressure SVOCs, thereby facilitating transport to surface waters. Model calculations suggest that if the PCB inventory is reduced, volatilization from near-shore Lake Ontario will become a net source of PCBs to air, but that neither near-shore Lake Ontario nor soil would become a significant volatilization PBDE source to air.

The fate and transport of cyanide in groundwater was investigated at gasworks sites in southeastern Australia. Two gasworks sites were investigated during this research: one in Tasmania and the other in Adelaide. The research followed three principal methods of investigation: field work, laboratory work and numerical modelling. The field work was aimed at observing the behaviour of cyanide in highly contaminated groundwater environments. Measured field parameters and laboratory analytical results from groundwater sampling were used to describe the hydrodynamics and hydrochemistry of the groundwater environment, providing a framework for groundwater flow and solute transport modelling. Groundwater and soil samples were also collected for use in laboratory experiments. The results from both field sites indicate contrasting hydrogeological environments, however, inorganic (metallic and non-metallic) and organic contaminants were measured in solution at both sites. The maximum concentrations observed at both sites were up to 5,300 mg/L CN(Total) (Adelaide site) and 21 mg/L CN(Total) (Tasmanian site). Results from geochemical modelling of solutes in groundwater at the field sites indicate that cyanide was predominantly in its free form in solution, with metallo- and alkali-cyanides also present.

Thesis--Frankfurt a. M. / Vita. Includes bibliographical references (p. 210-214).

Thesis (Ph. D.)--York University, 2001. Graduate Programme in Social and Political Thought. / Typescript. Includes bibliographical references (leaves 327-341). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ82827.