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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Role of bone morphogenetic protein in the liver

Li, Yining January 2011 (has links)
Elevated levels of plasma homocysteine (Hcy) are believed to be involved in several health problems, including liver fibrosis. However, the mechanism of Hcy induced liver injury remains to be further investigated. Although all hepatic cell types are involved in fibrogenesis, the activation and proliferation of hepatic stellate cells (HSCs) are considered to be central events. Moreover, it is reported that bone morphogenetic proteins (BMPs) play an important role in cell proliferation, differentiation and apoptosis. In this experiment, we examined the expression of BMPs in rat liver with hyperhomocysteinemia (HHcy) and in HSC cell lines at both mRNA and protein levels. The principal findings suggest that the expression of BMP-13 was significantly reduced in the liver of rats after 4 and 12 weeks of HHcy compared with that in control. Furthermore, there were significant increase in cell proliferation and modification of HSCs after Hcy treatment. In conclusion, a long term high methionine diet can cause a reduction of BMP-13 in the liver. The reduction of BMP-13 in the liver may contribute to liver injury induced by a high methionine diet.
2

Role of bone morphogenetic protein in the liver

Li, Yining January 2011 (has links)
Elevated levels of plasma homocysteine (Hcy) are believed to be involved in several health problems, including liver fibrosis. However, the mechanism of Hcy induced liver injury remains to be further investigated. Although all hepatic cell types are involved in fibrogenesis, the activation and proliferation of hepatic stellate cells (HSCs) are considered to be central events. Moreover, it is reported that bone morphogenetic proteins (BMPs) play an important role in cell proliferation, differentiation and apoptosis. In this experiment, we examined the expression of BMPs in rat liver with hyperhomocysteinemia (HHcy) and in HSC cell lines at both mRNA and protein levels. The principal findings suggest that the expression of BMP-13 was significantly reduced in the liver of rats after 4 and 12 weeks of HHcy compared with that in control. Furthermore, there were significant increase in cell proliferation and modification of HSCs after Hcy treatment. In conclusion, a long term high methionine diet can cause a reduction of BMP-13 in the liver. The reduction of BMP-13 in the liver may contribute to liver injury induced by a high methionine diet.
3

A preliminary work on highway runoff treatment design in Shanghai

WANG, XIAO January 2010 (has links)
<p> As highway runoff is one major source of non-point pollution in urban areas, removal of contaminants in runoff should be of great concern. In this paper, the necessity of highway runoff treatment in Shanghai was approved, systemic comparisons between runoff treatments were listed, detailed discussions on treatment approach selection were given based upon the availability of land. Three design models for highway runoff treatment were proposed; one focused on the urban highway, one focused on the suburb highway, and the third focused on the urban-suburb area. A survey among scientists studying runoff in China showed that the use of constructed wetlands was a remedy that was highly approved. They also supported the establishment of an urban runoff database. This paper will assist in the development of suitable treatment strategies for highway runoff in urban areas in China.</p>
4

A preliminary work on highway runoff treatment design in Shanghai

WANG, XIAO January 2010 (has links)
As highway runoff is one major source of non-point pollution in urban areas, removal of contaminants in runoff should be of great concern. In this paper, the necessity of highway runoff treatment in Shanghai was approved, systemic comparisons between runoff treatments were listed, detailed discussions on treatment approach selection were given based upon the availability of land. Three design models for highway runoff treatment were proposed; one focused on the urban highway, one focused on the suburb highway, and the third focused on the urban-suburb area. A survey among scientists studying runoff in China showed that the use of constructed wetlands was a remedy that was highly approved. They also supported the establishment of an urban runoff database. This paper will assist in the development of suitable treatment strategies for highway runoff in urban areas in China.
5

DESIGNING WATERSHED-SCALE STRUCTURAL BEST MANAGEMENT PRACTICES USING EVOLUTIONARY ALGORITHMS TO ACHIEVE WATER QUALITY GOALS

Kaini, Prakash D. 01 December 2010 (has links)
Water quality has been a major concern in the United States and elsewhere because of its impact on people's daily lives and on the environment. There are two main sources of water pollution: point sources and non-point sources, which are differentiated based on their mode of generation. Pollution generated from point sources has been effectively controlled by the implementation of the National Pollution Discharge Elimination System (NPDES) program, under the auspices of the 1972 Clean Water Act (CWA). However, a large portion of the nation's water remains polluted, mainly due to non-point sources of pollution. The Total Maximum Daily Load (TMDL) program within the CWA regulates water pollution by controlling both point and non-point sources. Structural and non-structural Best Management Practices (BMPs) have been recognized as effective measures for controlling non-point sources of pollution. These practices are designed on an on site basis in most cases. The objective of this research is to develop methodologies that can be used to design structural BMPs as measurements for controlling non-point sources of pollution (i.e. sediment and nutrients) on a larger spatial scale, that of a watershed. The Soil and Water Assessment Tool (SWAT), a semi-distributed model that simulates hydrological processes, has been selected for this study. The most sensitive model parameters with respect to discharge and sediment yield are identified by a parameter sensitivity analysis. Latin Hypercube Sampling One-at-a-time (LH-OAT), a global sensitivity analysis method, has been adopted for this purpose. SWAT has been calibrated by using these parameters to accurately simulate runoff and sediment yields from the watershed. An automatic calibration model using a genetic algorithm that optimizes the parameter values has been used. In addition, an uncertainty analysis of these selected parameters has been conducted to analyze the robustness of the model's predictions. Both single- objective and a multi-objective Optimal Control Models (OCM) have been developed by coupling SWAT with evolutionary algorithms, optimizing types, sizes, and locations of structural BMPs to achieve the desired level of treatment goals (the reduction of sediment and nutrient yields) at the watershed outlet. The single-objective OCM optimizes BMPs to a user-defined level of the treatment goals while the multi-objective OCM simultaneously optimizes BMPs for various degrees of treatment goals. The state-of-the-art multi-objective evolutionary algorithm that has been used in the study is the Non-Dominated Sorting Genetic Algorithm (NSGA-II). In addition, the single-objective OCM is applied to control increased sediment yield due to projected future climate scenarios. In conclusion, this research has developed methodologies that can cost-effectively improve water quality goals in agricultural watersheds by integrating a contemporary hydrological model with evolutionary algorithms.
6

Evaluation Of Proprietary Stormwater Treatment Devices In Field And Laboratory Conditions

Romah, Saheeda Marie 01 January 2005 (has links)
Proper stormwater management acknowledges both water quantity and water quality. Historically, stormwater quantity and quality have been separately considered; runoff was routed as quickly as possible into the nearest body of water. Although this alleviates potential flooding concerns, water quality is often compromised. Common stormwater quality problems include gross pollutants, sediment, nutrients, and heavy metals. The chronic elevated presence of these pollutants is detrimental to the environment. As a result, the government has passed legislature to protect waterways. The passage of the National Pollution Discharge Elimination System (NPDES) permit requires that municipalities implement stormwater treatment techniques, known as Best Management Practices (BMPs). Unfortunately, the NPDES document suggests treatment to the maximum extent possible, a vague description at best. This thesis reports a two-part study that endeavors to evaluate three of these proprietary treatment units manufactured by Stormceptor, BaySaver Separation Systems, and Continuous Deflective Separator (CDS) Technologies, Inc. to determine their performances. Each manufacturer produces a separator system that physically removes contaminants through the use of hydrodynamic flow principles. Phase I of the study focuses on monitoring two Stormceptor units and a CDS device in field conditions, while the second phase of the study evaluates each of the three treatment systems under laboratory conditions. The data analyses from the field study show the importance of proper maintenance. Storm events monitored after sump material removal showed great improvement over storm events occurring some time after the sump material removal. Furthermore, the treatment devices show a greater ability to remove pollutants from smaller storm events when compared with larger storm events. It is suggested that large storms cause scour of sediment previously trapped within the sump of the devices. An increase in the total suspended solid and nutrient concentrations, which were higher than the influent concentrations, was observed in both the field and laboratory studies. This could be explained by the fact that organics trapped by the treatment system decompose over time, therefore producing nutrient-rich water in the sump of the devices with higher concentration than the subsequent storm events. Some results are close to the minimum detection limit of the parameters being tested and small differences between influent and effluent load exaggerate the percent load differences. Consequently, there is little statistical significance between influent and effluent data, thus the data are summarized utilizing two methods. The methods include graphical representation of concentration and percent load difference, a method that normalized storms based on event size. In addition, a mass balance of gross litter was performed during the laboratory study.
7

Impacts of biota on bioretention cell function during establishment in the Midwest

Greene, Alicia Mathews January 1900 (has links)
Master of Science / Department of Biological & Agricultural Engineering / Stacy L. Hutchinson / To understand the region-specific effects of biota on function of bioretention cells, a lysimeter study was conducted at Kansas State University to determine how earthworms and native Kansas grasses impact runoff treatment and hydraulic function of a bioretention cell. This study also employed the Comprehensive Bioretention Cell (BRC) model to demonstrate how three seasons of growth could impact bioretention cell function. The model results of the first season of growth were then compared to field data. Results indicate that the interaction of plant roots and soil macrofauna over one growing season improved several aspects of bioretention cell function. The greatest increase in saturated hydraulic conductivity was in the treatment that included both plants and macrofauna. The presence of vegetation reduced ponding effects and increased water storage. Earthworm treatments had a lesser ability to store water. All treatments were effective in reducing the concentration of P in effluent. A large amount of N was released during all events from all treatments probably because of a high initial N content of the bioretention media. No treatment performed significantly better in improving water quality, indicating that macropore flow in the earthworm treatments did not induce a higher rate of pollutant transport.
8

Impact of Animal Waste Best Management Practices on the Bacteriological Quality of Surface Water

Cook, Mary Nicole Jr. 12 June 1998 (has links)
An extensive 10 year monitoring project was initiated in 1986 to examine the effects of a combination of BMPs on surface water quality within a watershed with complex land use. This research specifically examined bacteriological water quality and BMP impacts. Bimonthly grab samples were collected from four surface water monitoring stations, including the watershed outlet, and analyzed for fecal coliform, total coliform, and fecal streptococcus bacteria. Other data compiled from the watershed included hydrologic, meteorologic, geologic and land use data, also collected on a regular basis. Data were collected continuously throughout the project, and thus included both pre- and post-BMP monitoring data. BMP implementation included animal waste storage facilities, nutrient management plans, conservation tillage, alternative water sources for livestock, fences, vegetative filter strips, runoff diversions, and others. Statistical analysis of the monthly precipitation data indicated no significant difference in rainfall quantity between the pre-BMP and post-BMP monitoring periods. Monthly runoff totals increased 39% from the pre- to the post-BMP periods at the watershed outlet. Increases at all of the subwatershed outlets occurred as well (B, 40%; C, 38%; D, 16%). Statistical analysis did not show a significant difference in runoff between the two monitoring periods, except at station C, where post-BMP runoff was significantly greater than the values measured during the pre-BMP period. Overall reductions in the mean (geometric) levels of total coliform, fecal coliform and fecal streptococcus bacteria observed at the watershed outlet were 81%, 30% and 76%, respectively. Both parametric and nonparametric statistical analysis techniques were applied to the bacteriological data. Regression analysis of the fecal coliform data showed an increase during the pre-BMP period followed by a decrease post-BMP and a statistically significant difference between the two periods (p=0.004). No trends were evident. Only one of the four stations had a statistical difference between pre- and post-BMP fecal streptococcus data, however, a downward trend was present at every station. No statistically significant difference between the pre- and post-BMP total coliform bacteria was evident, although a downward trend was present at the watershed outlet. These findings indicate that the combination of BMPs implemented in the watershed were effective in reducing the loss of fecal bacteria to receiving streams via overland flow. / Master of Science
9

Evaluating a Vegetated Filter Strip in an Agricultural Field

Young, Alina Fay 12 May 2012 (has links)
The use of best management practices has become common in recent years, leading to the need for hydrologic models to predict their behavior and effectiveness. A vegetated filter strip at Mississippi State University was used to test two models: the Hydrologic Simulation Program-FORTRAN Best Management Practices Editor (HSPF BMPrac) and the System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN). Water samples were taken during the Spring of 2011 and tested for sediments and nutrients; HSPF was used for computing flows, sediments, and nutrients. The filter strip was not effective at pollutant removal with removal efficiency rates of 68.1, 91.7, 86.3, and 115.4 percent for total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and dissolved phosphorus (DP) respectively. Calibration of HSPF was successful for TSS with a R2 value of 0.52; nutrients were not as successful with R2 values of 0.11 and 0.43 for TN and TP.
10

Optimization of BMP Selection for Distributed Stormwater Treatment Networks

Hodges, Clayton Christopher 19 July 2016 (has links)
Current site scale stormwater management designs typically include multiple distributed stormwater best management practices (BMPs), necessary to meet regulatory objectives for nutrient removal and groundwater recharge. Selection of the appropriate BMPs for a particular site requires consideration of contributing drainage area characteristics, such as soil type, area, and land cover. Other physical constraints such as karst topography, areas of highly concentrated pollutant runoff, etc. as well as economics, such as installation and operation and maintenance cost must be considered. Due to these multiple competing selection criteria and regulatory requirements, selection of optimal configurations of BMPs by manual iteration using conventional design tools is not tenable, and the resulting sub-optimal solutions are often biased. This dissertation addresses the need for an objective BMP selection optimization tool through definition of an objective function, selection of an optimization algorithm based on defined selection criteria, development of cost functions related to installation cost and operation and maintenance cost, and ultimately creation and evaluation of a new software tool that enables multi-objective user weighted selection of optimal BMP configurations. A software tool is developed using the nutrient and pollutant removal logic found in the Virginia Runoff Reduction Method (VRRM) spreadsheets. The resulting tool is tested by a group of stormwater professionals from the Commonwealth of Virginia for two case studies. Responses from case study participants indicate that use of the tool has a significant impact on the current engineering design process for selection of stormwater BMPs. They further indicate that resulting selection of stormwater BMPs through use of the optimization tool is more objective than conventional methods of design, and allows designers to spend more time evaluating solutions, rather than attempting to meet regulatory objectives. / Ph. D.

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