The GTPase elongation factor G (EF-G) is an important player in the complex process of protein synthesis by bacterial ribosomes. Although extensively studied much remains to be learned about this fascinating protein. In the elongation phase, after incorporation of each amino acid into the growing peptide chain, EF-G translocates the ribosome along the mRNA template. In the recycling phase, when the synthesis of a protein has been completed, EF-G, together with ribosome recycling factor (RRF), splits the ribosome into its subunits. We developed the first in vitro assay for measuring the average time of a complete translocation step at any position along the mRNA. Inside the open reading frame, at saturating EF-G concentration and low magnesium ion concentration, translocation rates were fast and compatible with elongation rates observed in vivo. We also determined the complete kinetic mechanism for EF-G- and RRF-dependent splitting of the post-termination ribosome. We showed that splitting occurs only when RRF binds before EF-G and that the rate and GTP consumption of the reaction varies greatly with the factor concentrations. The antibiotic fusidic acid (FA) inhibits bacterial protein synthesis by binding to EF-G when the factor is ribosome bound, during translocation and ribosome recycling. We developed experimental methods and a theoretical framework for analyzing the effect of tight-binding inhibitors like FA on protein synthesis. We found that FA targets three different states during each elongation cycle and that it binds to EF-G on the post-termination ribosome both in the presence and absence of RRF. The stalling time of an FA-inhibited ribosome is about hundred-fold longer than the time of an uninhibited elongation cycle and therefore each binding event has a large impact on the protein synthesis rate and may induce queuing of ribosomes on the mRNA. Although ribosomes in the elongation and the recycling phases are targeted with similar efficiency, we showed that the main effect of FA in vivo is on elongation. Our results may serve as a basis for modelling of EF-G function and FA inhibition inside the living cell and for structure determination of mechanistically important intermediate states in translocation and ribosome recycling.

Hydraulic fracturing has unlocked a tremendous resource across the United States and around the world—shale. However, these processes have also come with a myriad of potential environmental effects, including a substantial demand for water. Hydraulic fracturing can require anywhere between two and four million gallons per well. The need for such large quantities of water can produce severe stresses on local water resources. In response to this issue, operators have developed several ways to alleviate some of the stresses brought on by the extensive water use such as alternative sourcing and reuse technologies. Companies are driven to exercise these options and decrease their fresh water usage for hydraulic fracturing processes for multiple reasons, including changes in regulation, to gain support of local communities, and to increase efficiencies of operations. Whatever the motivation may be, there are a variety of options companies have at their disposal to reduce fresh water demands—dependent on specific formation characteristics, the qualities and quantities of available water, among others. The Eagle Ford shale is one of the most rapidly growing shale plays in the country. However, this formation is located in a fairly arid part of the country. Because of meager average rainfall totals, water availability to meet demand is an issue of great concern. Due to nearly exponential increases in shale production, stresses on local water supplies have dramatically increased as well. The objectives of this thesis are as follows: 1) to establish the enormous resource that has become available; while still recognizing the environmental impacts associated with development processes, focusing primarily on water requirements and associated wastewater production; 2) to break down current water demand for shale development, as well as wastewater management practices in the Eagle Ford, with a brief comparison to other shale plays across the country; 3) to obtain an understanding of operator motivation—what factors affect wastewater management strategies; and 4) to analyze techniques operators presently have at their disposal to reduce fresh water demands, specifically through the use of brackish waters and recycling/reuse efforts, and finally to quantify these efforts to evaluate potential fresh water savings. / text

Three experiments were conducted to characterize the concentration of microorganisms in biosolids, the plume of aerosols created during land application of biosolids and the occupational risk of infection due to pathogens aerosolized during land application of biosolids in the United States. In all, more than three-hundred air samples were collected immediately downwind of biosolids applications throughout the United States using liquid impingers, and more than one-hundred air samples were collected downwind of microbially seeded, land applied water, which served as a conservative model system of aerosol generation. The novel model system made it possible to calculate the flux of microorganisms through a virtual plane defined by air samplers in vertical and horizontal arrays, located immediately downwind of a passing spray applicator. The rate of aerosolization during land application of biosolids near Tucson, Arizona, was calculated to be less than 33 plaque forming units (PFU) of coliphage and 10 colony forming units (CFU) of coliform bacteria per meter traveled by the spray applicator. Rates of aerosolization from the model system were shown to be much greater. To assess the risk to occupational health from bioaerosols generated during land application of biosolids, coliform bacteria, coliphages, and heterotrophic plate count (HPC) bacteria were enumerated from air and biosolids at 10 land application sites throughout the nation. The method of land application strongly influenced aerosolization, while relative humidity, temperature and wind speed showed limited correlation to concentrations of fecal indicator microorganisms in air. Occupational risks of infection and illness from aerosolized Salmonella and enteroviruses were calculated for a variety of land application scenarios. Realistic exposure scenarios carried occupational risks of Salmonella infection ranging from of 0.0001% to 0.013% per year. The corresponding occupational risk of infection from enteroviruses, using coxsackievirus A-21 as a model, ranged from 0.78% to 2.1% per year, depending on the type of activity performed by the worker. In addition, samples of biosolids from the Southwestern United States were characterized to provide up-to-date information about pathogens in biosolids for environmental regulators, biosolids producers, researchers, and public health agencies.

published_or_final_version / Journalism and Media Studies Centre / Master / Master of Journalism

This study consisted of laboratory and greenhouse experiments designed to determine the effect of sulfur waste materials on acidulation and other properties of calcareous soils. The laboratory experiment was conducted in the Soils, Water and Engineering Department, University of Arizona, for a period of nine weeks. Laveen soil (containing 6% CaCO₃) was treated with two levels of Morocco rock phosphate (0, 500 ppm P), and two different waste materials of sulfur, Cake S and Foam S, each with three levels (0, 5000, 10000 ppm). Treated soils were incubated for two periods (three and nine weeks) at 27°C and 66% water holding capacity. The design of the experiment was a complete randomized block with 24 treatments and two replications. Data were evaluated by analysis of variance and multiple means comparison tests for soil pH, soluble phosphorus, and sulfate, and regression analysis for the isotherm. Results showed that Foam sulfur had a greater effect as compared with Cake sulfur on soil pH, soluble phosphorus and sulfate and significantly shifted the isotherm to the right. Rock phosphate had no effect on soil pH and sulfate, but tended to decrease soluble phosphorus and shifted the isotherm to the left as compared with the control. The second experiment was conducted in the greenhouse near the Agricultural Sciences Building, University of Arizona, for a period of 32 weeks starting on August 20, 1979. Two calcareous soils, Pima and Laveen, (2% and 6% CaCO₃, respectively) were investigated with three levels of rock phosphate (0, 250, 500 ppm P), and three sources of sulfur (Cake, Foam and pure sulfur) each at two levels (0, 8000 ppm S). Two levels of super phosphate were used as a standard treatment. The chemical treatments were mixed with the soil and transferred to plastic pots and moistened to 70% water holding capacity, then covered with plastic sheets and incubated for eight weeks. Following the incubation, tomatoes were planted and grown for a six week period. Dry weights were measured only in the Pima soil but were eliminated due to poor stand in the Laveen soil. Barley was planted after the tomato harvest. Tomato and barley plants were irrigated with distilled water until the first harvest, after which barley was irrigated with tap water and CaSO₄ saturated to eliminate sulfur deficiency detected prior to the first harvest. The experiment was a complete randomized block design with 36 treatments and three replications. Data for soils and plants were evaluated by analysis of variance, multiple means comparison test, and regression analysis. From the results of this study the conclusions were as follows: (1) Foam sulfur tended to increase soluble P and Zn, lowered soil pH, and shifted the P isotherm to the right in the soil. Plant P and dry weight were increased more by the Foam S than Cake S and pure sulfur. However, Foam S tended to increase soluble salts more than Cake S and pure S. (2) Cake S also caused an increase in soluble P in the soil, reduced soil pH, and increased plant P and dry weight as well, although the effects were less than with Foam S. (3) Rock phosphate plus sulfur resulted in an increase in soluble P after 32 weeks of application. (4) Soils with low CaCO₃ content, higher organic matter content, and higher cation exchange capacity favored increased oxidation of sulfur to sulfate resulting in increased soluble P and lower soil pH. (5) Linear regression analysis of the P sorption isotherm was carried out by plotting the P remaining in the solution (ppm) on the X-axis versis P sorbed by the soil (ppm); a linear power function resulted. By this relationship, any regression equation can be used to evaluate the P status of a soil and the statistical differences between treatments.

This dissertation aims to use a system thinking approach to describe and evaluate the Lead-Acid Battery Recycling Program in British Columbia, compare it with other provincial regulated recycling programs and identify strategies on how it can be improved. The research is presented in the manuscript based format, comprised of four interrelated chapters. Following the introduction, chapter 2 describes a multiple regression analysis to assess how various factors identified by informed stakeholders have contributed to recycling rate in 14 transportation zones from 1995 to 2005. This study demonstrates that the existing recycling scheme ineffectively promotes recycling as it has achieved an average of 75% over the past 13 years with large fluctuations among transportation zones. The regression also shows that recycling rate of transportation zones are not highly influenced by LME lead prices and Transportation Incentive (which can be explained by the strong market power of the recycling plants responsible for setting up the price of scrap lead to which the collectors respond). Chapter 3 identifies key components that influence the performance of varied recycling systems based on a comparative analysis of provincial recycling systems informed by expert interviews. In chapter 4, comprehensive evaluation criteria for the lead-acid battery recycling program is developed based on objectives and performance measures elicited through an extensive stakeholder consultation process with various individuals and organizations. Fundamental objectives identified by stakeholders include: reduce environmental impacts, reduce occupational health impacts, reduce net costs, increase equity in resource consumption patterns and increase systematic learning. In chapter 5, we use multiple criteria decision analysis (MCDA) to design and assess effective recycling strategies to meet societal objectives previously identified in the chapter 4. Recycling strategies were compiled using the results of chapter 3. The results reveals that the optimal policy for the lead-acid battery recycling system combines a return to retailer program financed through an advanced disposal fee included in the battery price in combination with increased plant or recycling capacity domestically. This research also provides relevant contributions to the refining and application of value-focused thinking and decision analysis methodologies.

This Master thesis connects two interrelated environmental issues – climate change and waste management. Both have been under discussion for few decades and are currently two of the top priorities on EU’s environmental agenda. The goal of this thesis is to find out in what ways waste management in Lithuania and Sweden can contribute towards reducing global warming and how the release of greenhouse gases could be reduced. Four different material flows – food, metal, plastic, and paper and cardboard – are examined and greenhouse gas reduction potentials are calculated, using data found in various reports. The case studies of Lithuania and Sweden help to find out the strong and the weak points of waste management systems in the two countries by comparing their differences. The results show that in Lithuania significant greenhouse gas reductions can be achieved by improving waste sorting and decreasing disposal rates, whereas in Sweden waste management is well-developed, but still could be upgraded by switching to more efficient waste treatment practices. The thesis is concluded by indicating the pros and cons of waste management in Lithuania and Sweden.

Two things struck me during my time in Dharavi. The first was the bad public health and the second the ingenuity and entrepreneurial spirit of the people who lived there. The health issues, a result of inadequate sanitation, can be directly linked to the shortage of toilets. For every toilet there are a thousand users and because of this over a quarter of the people in Dharavi choose instead to publicly defecate. On the other side of the coin however, stands Dharavi’s remarkable recycling industry and in Dharavi alone 80% of Mumbai’s plastic waste is recycled and given new use. The concept revolves around recyclability and combining industry with sanitation; recycling the produced waste and generating income. If there’s a way to profit from human waste it is likely that people would go to certain lengths to collect the necessary material. By removing the waste and converting it to humanure, positive side effect would include cleaner streets and in general a healthier population. The idea is therefore to build a waste management facility where income is generated through the collected waste and used to improve the surrounding community. In this proposed space you can go to the toilet, throw away your trash and food waste and even use the functions provided to do chores or simply relax. The food and human waste from toilets could be used as fertilizer and sold for a profit or perhaps even used as fuel. The garbage could be collected and sorted on spot and then sold onwards for further refinement.

Polycarbonates are found in a variety of common products in daily life due to their favorable mechanical and electrical properties. In addition, they are widely used in biomedical areas due to their stability and biological inertness. Therefore, the production of polycarbonates became an important industrial process in the past decades. However, the current industrial process usually requires toxic phosgene gas as a starting material. Thus, the environmentally benign route by using metal catalyzed couplings of epoxides and CO_(2) to produce polycarbonates has received attention from researchers. In this dissertation, metal catalyzed CO_(2)/cyclic ether copolymerization, depolymerization of polycarbonates, and the equilibria between polycarbonate and corresponding six-membered cyclic carbonate will be investigated. First, the Co(III) catalyzed copolymerizations of CO_(2) and various epoxides with electron-withdrawing substituents to afford polycarbonates are examined. Comparative kinetic studies were performed via in situ infrared measurements as a function of temperature to assess the activation barriers for the production of cyclic carbonate versus copolymer involving electronically different epoxides: styrene oxide, epichlorohydrin, and propylene oxide. Thermodynamically stable cyclic carbonate byproducts are produced during the course of the reaction from the degradations of propagating polymer chains. The depolymerization reactions of several polycarbonates produced from the completely alternating copolymerization of styrene oxide, epichlorohydrin, propylene oxide, cyclohexene oxide, indene oxide, and cyclopentene oxide with carbon dioxide have been investigated. Various reaction pathways can be found under different reaction conditions, including process involving chain-end backbiting and radical intermediates. Temperature-dependent kinetic studies have provided energy of activation barriers for cyclic carbonate formation. In addition, the generated monomeric materials from the degradation of select polycarbonates show the possibility of chemical recycling of plastic waste. For the copolymers made from CO_(2) and oxetane derivatives, this study focuses on the influence of steric hindrance in the 3-position of the monomer oxetane. The (salen)CrCl/onium salt catalyzed coupling reactions of these oxetane derivatives and carbon dioxide are reported. Depolymerizations of copolymers to their corresponding cyclic carbonates were also studied. In addition, several six-membered cyclic carbonates were synthesized to examine their equilibria between monomeric cyclic carbonates and their corresponding polycarbonates.

In South Africa, sustainable development is set in the context of two separate economies. The second of these economies consists of the rural population and is characterised by poverty and stagnant development. Sustainable development is an increasingly topical concept which highlights the need for development to proceed in a manner that does not deplete natural resources. In addition to narrowing the gaps between the various classes (layers) in an economy, the key ‘ingredients’ of sustainable economic development include “natural resource management, food, water, and energy access, provision and security” (Blignaut, 2009: cited in Blignaut and van der Elst, 2009: 14). A biodigester is a potential solution to some of the difficulties faced by remote rural populations. Biodigester systems are submerged tanks capable of producing a nutrient rich fertiliser and combustible gas when consistently fed with organic matter and water. A biodigester may be one simple answer to the key ingredient needs of sustainable development – reducing the depletion of natural resources, providing clean burning energy for cooking and fertiliser for growing food. The potential is clear for biodigesters to aid in the process of sustainable development. The question to be analysed is whether this technology would be financially and economically feasible for installation and use in rural households. This thesis focuses on a typically remote and rural community in KwaZulu-Natal, South Africa, in order to assess the potential feasibility of a biodigester system. The appraisal takes the form of a Cost Benefit Analysis (CBA) and aims to establish whether or not this technology is financially feasible for individual rural households and/or economically beneficial to society. / Thesis (M.Com.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.