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- Title
- THE EFFECT OF FREE CHLORINE AND CHLORAMINES ON LEAD RELEASE IN A DISTRIBUTION SYSTEM.
- Creator
-
Vasquez, Ferdinand, Taylor, James, University of Central Florida
- Abstract / Description
-
Total lead release in drinking water in the presence of free chlorine and chloramine residuals was investigated in field, laboratory and fundamental investigations for finished waters produced from ground (GW), surface (SW), saline (RO) and blended (B) sources. Field investigations found more total lead was released in the presence of chloramines than in the presence of free chlorine for RO and blended finished waters; however, there were no statistical differences in total lead release to...
Show moreTotal lead release in drinking water in the presence of free chlorine and chloramine residuals was investigated in field, laboratory and fundamental investigations for finished waters produced from ground (GW), surface (SW), saline (RO) and blended (B) sources. Field investigations found more total lead was released in the presence of chloramines than in the presence of free chlorine for RO and blended finished waters; however, there were no statistical differences in total lead release to finished GW and SW. Laboratory measurements of finished waters oxidation-reduction potential (ORP) were equivalent by source and were not affected by the addition of more than 100 mg/L of sulfates or chlorides, but were significantly higher in the presence of free chlorine relative to chloramines. Development of Pourbaix diagrams revealed the PbO2 was the controlling solid phase at the higher ORP in the presence of free chlorine and Pb3(CO3)2(OH)2(s) (hydrocerussite) was the controlling solid phase in the presence of chloramines at the lower ORP, which mechanistically accounted for the observed release of total lead as PbO2 is much less soluble than hydrocerussite. The lack of differences in total lead release to finished GW and SW was attributed to differences in water quality and intermittent behavior of particulate release from controlling solid films.
Show less - Date Issued
- 2005
- Identifier
- CFE0000533, ucf:46427
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000533
- Title
- REGULATION OF VLDL TRAFFICKING BY ORP 10.
- Creator
-
Wessels, Philip, Siddiqi, Shadab, University of Central Florida
- Abstract / Description
-
Of the challenges facing the improvement of human health, none has taken the forefront quite like the endeavor to discover novel treatments for heart disease. As heart disease has now become the leading cause of death throughout the world , the medical community has made incredible strides in the mission to treat atherosclerosis which is the major contributor to heart disease. Very Low Density Lipoproteins (VLDL) are secreted by the liver and subsequently converted to Low Density Lipoproteins...
Show moreOf the challenges facing the improvement of human health, none has taken the forefront quite like the endeavor to discover novel treatments for heart disease. As heart disease has now become the leading cause of death throughout the world , the medical community has made incredible strides in the mission to treat atherosclerosis which is the major contributor to heart disease. Very Low Density Lipoproteins (VLDL) are secreted by the liver and subsequently converted to Low Density Lipoproteins (LDL). Many factors contribute to the narrowing of the arterial walls, however oxidized LDL is the main factor that leads to the deposition of plaque, leading to atherosclerosis pathologies. Recently, a main focus of research into atherosclerotic processes has been the synthesis and trafficking of VLDL in hepatocytes. The rate-limiting step for the secretion of VLDL from the liver has been determined to be the transport of VLDL from the endoplasmic reticulum (ER) to the Golgi apparatus. VLDL molecules are transported in a specialized transport vesicle the Very Low Density Lipoprotein Transport Vesicle (VTV) . VLDL's core protein, apolipoproteinB-100 (apoB100), is initially lipidated in the ER, and then subsequently delivered to the Golgi apparatus where the VLDL molecule undergoes maturation involving further lipidation and glycosylation of apoB100. Oxysterol Binding Proteins (OSBP) and the sub family OSBP Related Proteins (ORP) have been implicated in many different trafficking processes, mainly the trafficking of sterols, cholesterol, and lipids. Recently, ORP 10 was shown to be a negative regulator of apoB100 secretion in growth medium . Using co-immunoprecipitation, the current study shows that ORP 10 interacts with VLDL's core protein apoB100 directly. Employing an in vitro budding assay, we show that the blocking of ORP 10 with a specific antibody against ORP10 increases VTV formation from the ER. Given that the ER to Golgi pathway is the rate-limiting step in overall VLDL secretion, these findings support the conclusion that ORP 10 is a negative regulator of VLDL trafficking between the ER and Golgi, and that this process is mediated by the ORP 10 protein binding with apoB100.
Show less - Date Issued
- 2015
- Identifier
- CFH0004866, ucf:45491
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004866