The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Li Weixi - One of the best experts on this subject based on the ideXlab platform.
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Quantitative analyses of unit train safety and railroad tank car implementation policy
2020Co-Authors: Li WeixiAbstract:Railroads play a critical role in the transportation and economic prosperity of North America. Train safety has improved considerably over the past decade. However, with the large volume of traffic, accidents still occur. Derailments are the most common type of train accident recorded in the Federal Railroad Administration’s Rail Equipment Accident/Incident database. The research presented in this thesis focuses on derailments and releases of hazardous materials, specifically three topics related to this general theme: unit train loading condition, the effect of train configuration on risk, and policies for implementation schedule for safer tank cars. The effect of loading condition on unit-train derailment occurrence, causes and severity is described in Chapter 2. An algorithm was developed to identify derailments of loaded and empty unit trains on mainlines and sidings recorded in the Federal Railroad Administration database. A dataset of these accidents for the 15-year period from 2001 to 2015 was developed and analyzed. The frequency of derailments for both loaded and empty unit trains declined by more than 50%. The average number of cars derailed per accident fluctuated for both loading conditions but showed no particular trend. Approximately five times more loaded unit train derailments were recorded than empty unit trains but in the absence of specific unit train traffic data, inferences about rates are not possible. Loaded unit trains were more than four times heavier than empty unit trains, and loaded train derailments tended to involve more cars than empty train derailments. The distribution of derailment causes differed for loaded and empty unit trains. Loaded trains most frequently derailed due to broken rails and welds, while the leading cause of empty train derailments was obstructions, which included severe weather. Over 90% of the derailments of loaded and empty unit trains considered in this study occurred on mainline tracks, and the distribution of causes differed between mainline and siding tracks. Chapter 3 presents an analysis of the risk associated with transporting hazardous materials by unit trains versus manifest trains. While unit trains offer efficient transportation of hazardous materials, if these trains derail, the consequences can be particularly severe. Transporting hazardous materials in unit trains reduces exposure to accidents compared to transporting the same quantity of material in a larger number of manifest trains. However, in the event that a derailment of a unit train does occur, the consequences may be greater. Conversely, transportation in a larger number of manifest trains increases the exposure to derailments, but may reduce the severity if an accident occurs. An investigation of these trade-offs using the Multiple Tank Car Release model to conduct a series of simulations is presented. As part of this analysis the effect of using DOT 111 tank cars was compared to use of DOT 117 tank cars. Both the likelihood and consequence of transporting hazardous materials in these different train configurations were estimated and the metrics used to estimate risk were the distributions of number of tank cars derailed, number of tank cars releasing, and quantity released. Use of safer tank car specifications can substantially reduce the consequences and risk of derailments involving hazardous materials. Nevertheless, there are practical and financial considerations associated with replacing the existing fleet with new cars. Safer tank cars are generally more expensive to build and operate, and there may be practical constraints due to manufacturing capacity. In the late 2000s, the government and industry were faced with a choice of immediate adoption of a safer tank car for Toxic Inhalation Hazard materials, or awaiting the results of a research and development project to develop an even safer car. The discussion between the government and industry regarding phase-in policies for safer tank cars led to the research described in Chapter 4. Specifically, how would different policies regarding deferral of the decision to implement safer cars, and the schedule of replacement affect risk. In Chapter 4, a methodology is presented to quantify the risk associated with rail transport of the top two Toxic Inhalation hazard materials by shipment, ammonia and chlorine. A network risk analysis model was used in conjunction with routing information, population, and the Multiple Tank Car Release model to estimate several risk metrics under different implementation scenarios.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste
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Quantitative analyses of unit train safety and railroad tank car implementation policy
2018Co-Authors: Li WeixiAbstract:Railroads play a critical role in the transportation and economic prosperity of North America. Train safety has improved considerably over the past decade. However, with the large volume of traffic, accidents still occur. Derailments are the most common type of train accident recorded in the Federal Railroad Administration’s Rail Equipment Accident/Incident database. The research presented in this thesis focuses on derailments and releases of hazardous materials, specifically three topics related to this general theme: unit train loading condition, the effect of train configuration on risk, and policies for implementation schedule for safer tank cars. The effect of loading condition on unit-train derailment occurrence, causes and severity is described in Chapter 2. An algorithm was developed to identify derailments of loaded and empty unit trains on mainlines and sidings recorded in the Federal Railroad Administration database. A dataset of these accidents for the 15-year period from 2001 to 2015 was developed and analyzed. The frequency of derailments for both loaded and empty unit trains declined by more than 50%. The average number of cars derailed per accident fluctuated for both loading conditions but showed no particular trend. Approximately five times more loaded unit train derailments were recorded than empty unit trains but in the absence of specific unit train traffic data, inferences about rates are not possible. Loaded unit trains were more than four times heavier than empty unit trains, and loaded train derailments tended to involve more cars than empty train derailments. The distribution of derailment causes differed for loaded and empty unit trains. Loaded trains most frequently derailed due to broken rails and welds, while the leading cause of empty train derailments was obstructions, which included severe weather. Over 90% of the derailments of loaded and empty unit trains considered in this study occurred on mainline tracks, and the distribution of causes differed between mainline and siding tracks. Chapter 3 presents an analysis of the risk associated with transporting hazardous materials by unit trains versus manifest trains. While unit trains offer efficient transportation of hazardous materials, if these trains derail, the consequences can be particularly severe. Transporting hazardous materials in unit trains reduces exposure to accidents compared to transporting the same quantity of material in a larger number of manifest trains. However, in the event that a derailment of a unit train does occur, the consequences may be greater. Conversely, transportation in a larger number of manifest trains increases the exposure to derailments, but may reduce the severity if an accident occurs. An investigation of these trade-offs using the Multiple Tank Car Release model to conduct a series of simulations is presented. As part of this analysis the effect of using DOT 111 tank cars was compared to use of DOT 117 tank cars. Both the likelihood and consequence of transporting hazardous materials in these different train configurations were estimated and the metrics used to estimate risk were the distributions of number of tank cars derailed, number of tank cars releasing, and quantity released. Use of safer tank car specifications can substantially reduce the consequences and risk of derailments involving hazardous materials. Nevertheless, there are practical and financial considerations associated with replacing the existing fleet with new cars. Safer tank cars are generally more expensive to build and operate, and there may be practical constraints due to manufacturing capacity. In the late 2000s, the government and industry were faced with a choice of immediate adoption of a safer tank car for Toxic Inhalation Hazard materials, or awaiting the results of a research and development project to develop an even safer car. The discussion between the government and industry regarding phase-in policies for safer tank cars led to the research described in Chapter 4. Specifically, how would different policies regarding deferral of the decision to implement safer cars, and the schedule of replacement affect risk. In Chapter 4, a methodology is presented to quantify the risk associated with rail transport of the top two Toxic Inhalation hazard materials by shipment, ammonia and chlorine. A network risk analysis model was used in conjunction with routing information, population, and the Multiple Tank Car Release model to estimate several risk metrics under different implementation scenarios
Radharaman Ray - One of the best experts on this subject based on the ideXlab platform.
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Transient receptor potential (TRP) channels as a therapeutic target for intervention of respiratory effects and lethality from phosgene
Toxicology letters, 2015Co-Authors: Devon Andres, Brian Keyser, Betty Benton, Ashley A Melber, Dorian S Olivera, Wesley W. Holmes, Danielle C. Paradiso, Dana R. Anderson, Radharaman RayAbstract:Phosgene (CG), a Toxic Inhalation and industrial hazard, causes bronchoconstriction, vasoconstriction and associated pathological effects that could be life threatening. Ion channels of the transient receptor potential (TRP) family have been identified to act as specific chemosensory molecules in the respiratory tract in the detection, control of adaptive responses and initiation of detrimental signaling cascades upon exposure to various Toxic Inhalation hazards (TIH); their activation due to TIH exposure may result in broncho- and vasoconstriction. We studied changes in the regulation of intracellular free Ca(2+) concentration ([Ca(2+)]i) in cultures of human bronchial smooth muscle cells (BSMC) and human pulmonary microvascular endothelial cells (HPMEC) exposed to CG (16ppm, 8min), using an air/liquid interface exposure system. CG increased [Ca(2+)]i (p
Sven-eric Jordt - One of the best experts on this subject based on the ideXlab platform.
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Transient receptor potential channels in pulmonary chemical injuries and as countermeasure targets.
Annals of the New York Academy of Sciences, 2020Co-Authors: Satyanarayana Achanta, Sven-eric JordtAbstract:The lung is highly sensitive to chemical injuries caused by exposure to threat agents in industrial or transportation accidents, occupational exposures, or deliberate use as weapons of mass destruction (WMD). There are no antidotes for the majority of the chemical threat agents and Toxic Inhalation hazards despite their use as WMDs for more than a century. Among several putative targets, evidence for transient receptor potential (TRP) ion channels as mediators of injury by various Inhalational chemical threat agents is emerging. TRP channels are expressed in the respiratory system and are essential for homeostasis. Among TRP channels, the body of literature supporting essential roles for TRPA1, TRPV1, and TRPV4 in pulmonary chemical injuries is abundant. TRP channels mediate their function through sensory neuronal and nonneuronal pathways. TRP channels play a crucial role in complex pulmonary pathophysiologic events including, but not limited to, increased intracellular calcium levels, signal transduction, recruitment of proinflammatory cells, neurogenic inflammatory pathways, cough reflex, hampered mucus clearance, disruption of the integrity of the epithelia, pulmonary edema, and fibrosis. In this review, we summarize the role of TRP channels in chemical threat agents-induced pulmonary injuries and how these channels may serve as medical countermeasure targets for broader indications.
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Toxic effects of chlorine gas and potential treatments a literature review
Toxicology Mechanisms and Methods, 2019Co-Authors: Satyanarayana Achanta, Sven-eric JordtAbstract:Chlorine gas is one of the highly produced chemicals in the USA and around the world. Chlorine gas has several uses in water purification, sanitation, and industrial applications; however, it is a Toxic Inhalation hazard agent. Inhalation of chlorine gas, based on the concentration and duration of the exposure, causes a spectrum of symptoms, including but not limited to lacrimation, rhinorrhea, bronchospasm, cough, dyspnea, acute lung injury, death, and survivors develop signs of pulmonary fibrosis and reactive airway disease. Despite the use of chlorine gas as a chemical warfare agent since World War I and its known potential as an industrial hazard, there is no specific antidote. The resurgence of the use of chlorine gas as a chemical warfare agent in recent years has brought speculation of its use as weapons of mass destruction. Therefore, developing antidotes for chlorine gas-induced lung injuries remains the need of the hour. While some of the pre-clinical studies have made substantial progress in the understanding of chlorine gas-induced pulmonary pathophysiology and identifying potential medical countermeasure(s), yet none of the drug candidates are approved by the U.S. Food and Drug Administration (FDA). In this review, we summarized pathophysiology of chlorine gas-induced pulmonary injuries, pre-clinical animal models, development of a pipeline of potential medical countermeasures under FDA animal rule, and future directions for the development of antidotes for chlorine gas-induced lung injuries.
G. Antipas - One of the best experts on this subject based on the ideXlab platform.
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Hydrogen sulfide poisoning : management and complications
Angiology, 1995Co-Authors: Leonidas Gregorakos, G. Dimopoulos, S. Liberi, G. AntipasAbstract:Hydrogen sulfide poisoning is a rare but devastating injury. Four of 8 cases of Toxic Inhalation of hydrogen sulfide are presented with special attention to the life-threatening complications. Four patients died at the scene of the accident and the remaining 4 had been hospitalized in the Intensive Care Unit (ICU). One patient died in the hospital from cardiogenic pulmonary edema and circulatory failure (pulmonary wedge pressure > 30 mmHg) and 3 patients left the hospital in good health although they presented serious complications. One of them left the hospital with a temporary pacemaker, and 1 of the 2 others died after two months owing to myocardial infarction. The authors discuss in detail the clinical features of this condition and emphasize the need for urgent and appropriate therapy as well as the need for safe environmental conditions.
Benjamin J Luft - One of the best experts on this subject based on the ideXlab platform.
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shortened leukocyte telomere length is associated with reduced pulmonary function and greater subsequent decline in function in a sample of world trade center responders
Scientific Reports, 2019Co-Authors: Sean A P Clouston, Norman H Edelman, Abraham Aviv, Candace Stewart, Benjamin J LuftAbstract:The objective of this study was to examine whether shorter leukocyte telomere length (LTL) is associated with more rapid pulmonary function decline in a longitudinal study of World Trade Center (WTC) responders. WTC responders (N = 284) participating in a monitoring study underwent blood sampling and were followed prospectively for spirometric outcomes. A single blood sample was taken to measure LTL using southern blotting. Outcomes included percent-predicted one-second forced expiratory volume (FEV1%), forced vital capacity (FVC%), and the FEV1/FVC ratio. In a subset, percent-predicted diffusing capacity (DLCO%) was also measured. Longitudinal modeling examined prospectively collected information over five years since blood was banked was used to examine the rate of change in pulmonary functioning over time. Severity of WTC exposure was assessed. Shorter LTL was associated with lower FEV1% and FVC% at baseline. For example, 29.9% of those with LTL <6.5 kbps had FEV1% <80% whereas only 12.4% of those with LTL ≥6.5 had FEV1% <80% (RR = 2.53, 95%CI = [1.70–3.76]). Lower DLCO% was also significantly associated with shorter LTL. Longitudinal models identified a prospective association between shorter LTL and greater yearly rates of decline in FEV1% (0.46%/year, 95%CI = [0.05–0.87]) and in the FEV1/FVC ratio (0.19%/year, 95%CI = [0.03–0.36]). There were no associations between severity of exposure and either LTL or pulmonary function. Longitudinal analyses revealed that shorter LTL, but not severity of WTC exposures, was associated with poorer pulmonary functioning and with greater subsequent decline in pulmonary functioning over time. These findings are consistent with the idea that shortened LTL may act as a biomarker for enhanced pulmonary vulnerability in the face of acute severe Toxic Inhalation exposures.