Characterization Of Dopamine Transporter Amino Terminal Palmitoylation And Neurotoxic Substrate Activity

The projects described in this dissertation revolve around the functional consequences experienced by the transport protein for the neurotransmitter dopamine resulting from alterations to its palmitoylation condition or exposure to Parkinson disease-inducing transport substrates. This membrane-resident transport protein, pragmatically termed the dopamine transporter, relocates dopamine from extracellular areas of receptor sites of action to intracellular sequestration; the dopamine transporter is a powerful mediator of dopamine signaling. As such, genetic, toxicant, or chronic breakdown of dopamine transporter function is associated with multiple psychological abnormalities. Biomedical research has produced several pharmacotherapies for maladies like depression, attention deficit/hyperactivity disorder, and addiction, some of which produce their therapeutic profiles by modulating dopamine transporter function. The potential for pharmacological manipulation of the dopamine transporter is, however, not without its dark side. Dopamine’s critical role in the neurotransmission of reward and pleasure render the dopamine transporter a favorite target of illicit, addictive drugs of abuse like cocaine and several flavors of amphetamine. All of these factors make intimate understanding of the many mechanisms involved in the dopamine transporter’s function relevant not only to mental, but also societal health. This dissertation explores aspects of dopamine transporter mechanistic regulation which, once more thoroughly understood, may be modified to allow finer control over transporter operation, generating novel approaches to mental health treatment. The first study investigates site identification and functional characterization of post-translational modification of the dopamine transporter by a lipid moiety, palmitic acid. Palmitic acid, hexadecanoic acid in IUPAC nomenclature, is a saturated 16 carbon fatty acid whose attachment to proteins is termed S-palmitoylation. This lipidation process is executed by an array of enzymes belonging to the acyl transferase class of the gene name zDHHC. Importantly, S-palmitoylation is reversible: a protein’s palmitoylation status can change in response to cell stimuli or the palmitoylated protein’s activation. As palmitate is of an aliphatic nature, its attachment creates a hydrophobic protein microenvironment around the site of its augmentation which propitiates its insertion into likewise hydrophobic loci – usually membranes – which induces a protein-specific functional outcome. A combination of dopamine transporter proteolysis, site-directed mutagenesis, acyl-biotinyl exchange, surface biotinylation, and forward and reverse dopamine transport assays implicate two N-terminal cysteine residues as sites of palmitate incorporation, in addition to the previously analyzed C-terminal site, and reveal a role for this lipid modification in dopamine transporter-mediated dopamine efflux. The second project seeks to further understand the dopamine transporter’s contribution to Parkinson disease. The hallmark of this disease is a loss of motor coordination precipitated by selective death of nigro-striatal dopamine neurons and concomitant depletion of dopamine neurotransmission in the movement planning and execution region of the brain – the striatum. The selective loss of these neurons directly correlates with dopamine transporter expression; indeed, even amongst dopamine neuronal pathways, the nigro-striatal fiber, which is lost to the greatest extent of these, has the highest transporter expression. It is for this reason the dopamine transporter has been a focus of Parkinson disease research. This study utilizes the dopamine transporter substrates 6-hydroxydopamine and 1-methyl-4-phenylpyridinium, which induce cell death through a panoply of biochemical mechanisms and are used to generate Parkinsonian symptoms in animal models, to probe for aberrant dopamine transporter function and post-translational modification. This inquiry revealed that, though these compounds induce cell death through similar mechanisms, their dopamine transporter-specific effects are quite different. Interestingly, 1-methyl-4-phenylpyridinim is a strong inducer of dopamine uptake downregulation and dopamine efflux, a phenomenon now implicated in Parkinson disease onset, while 6-hydroxydopamine mitigates this efflux event as well as attenuates transporter phosphorylation. Overall, this dissertation argues for the existence of N-terminal palmitoylation of the dopamine transporter, that palmitoylation is an additional contributor to the dopamine efflux paradigm, that transporter-mediated efflux may contribute to Parkinson disease onset, and that some of the transporter-specific effects of 6-hydroxydopamine may be exploited to alleviate neuropsychiatric maladies associated with aberrant dopamine efflux

Impact Of Coal Derived Impurities On The Performance Of Hydrogen Separation Membranes

In order to facilitate the use of hydrogen in integrated gasification combined-cycle (IGCC) applications or as a transportation fuel, hydrogen-from-coal technologies that are capable of managing carbon will be needed. Many technologies are under development for the separation of hydrogen from coal-derived syngas, and among the most promising are hydrogen separation membranes. Studies indicate a significant IGCC plant efficiency increase can be realized if warm-gas cleanup and hydrogen separation membranes are used in place of conventional technologies. These membranes provide the potential to produce hydrogen while simultaneously separating CO2 at system pressure. Membrane development to date has primarily occurred on bottle-derived syngas, and the impact of coal-derived impurities is largely unknown. Gasification syngas typically has many impurities that, if not removed, will poison most hydrogen separation materials. In order to commercialize this promising technology, scale-up to bench- and pilot-scale gasifiers is required so that the impact of impurities can be evaluated. Sulfur and other coal derived impurities such as chlorine, sodium, mercury, and arsenic have the potential to deteriorate the performance of hydrogen separation membranes. It is unknown if species such as mercury will have an impact on the membrane performance, but mercury does remain in the gas phase and can cause environmental concerns. Commercially available technologies exist today to remove the contaminants from the syngas prior to exposure to the membranes. The goal of this work was to determine if the warm gas clean up techniques available today are adequate to protect hydrogen separation membranes from performance degradations caused by the impurities found in coal. To test this hypothesis, pilot-scale gasifiers at the Energy & Environmental Research Center (EERC) were used to produce coal-derived syngas, and solid sorbents were used for warm-gas cleanup and water-gas shift. Three hydrogen separation membranes were exposed to coal-derived syngas for several hundred hours. Membrane materials that were exposed to coal derived syngas during the testing were acquired and analyzed for contaminants. This work explores whether the warm gas cleanup techniques employed were adequate to prevent performance degradation of hydrogen separation membranes. The U.S. Department of Energy\u27s National Energy Technology Laboratory and the State of Wyoming funded the experimental effort

Link-layer Security in TSCH Networks: Effect on Slot Duration

International audienceThe IEEE802.15.4e-2012 standard is widely used in multi-hop wireless Industrial Internet of Things (IIoT)applications. In the Time-Slotted Channel Hopping (TSCH) mode, nodes are synchronized, and time iscut into timeslots. A schedule orchestrates all communications, resulting in high reliability and low poweroperations. A timeslot must be long enough for a node to send a data frame to its neighbor, and for thatneighbor to send back an acknowledgment. Shorter timeslots enable higher bandwidth and lower latency, yetthe minimal timeslot duration is limited by how long link-layer security operations take. We evaluate theoverhead of link-layer security in TSCH networks in terms of minimal timeslot length, memory footprint,and energy consumption. We implement full link-layer security on a range of hardware platforms, exploringdierent hardware/software implementation strategies. Through an extensive measurement campaign, wequantify the advantage of hardware accelerations for link-layer security, and show how the minimal durationof a timeslot varies between 9 ms and 88 ms for the most common conguration, depending on hardwaresupport. Furthermore, we also highlighted the impact that the timeslot duration has on both high-levelapplication design and energy consumption

Long-Term Demonstration of Hydrogen Production from Coal at Elevated Temperatures Year 6 - Activity 1.12 - Development of a National Center for Hydrogen Technology

The Energy & Environmental Research Center (EERC) has continued the work of the National Center for Hydrogen Technology® (NCHT®) Program Year 6 Task 1.12 project to expose hydrogen separation membranes to coal-derived syngas. In this follow-on project, the EERC has exposed two membranes to coal-derived syngas produced in the pilot-scale transport reactor development unit (TRDU). Western Research Institute (WRI), with funding from the State of Wyoming Clean Coal Technology Program and the North Dakota Industrial Commission, contracted with the EERC to conduct testing of WRI’s coal-upgrading/gasification technology for subbituminous and lignite coals in the EERC’s TRDU. This gasifier fires nominally 200–500 lb/hour of fuel and is the pilot-scale version of the full-scale gasifier currently being constructed in Kemper County, Mississippi. A slipstream of the syngas was used to demonstrate warm-gas cleanup and hydrogen separation using membrane technology. Two membranes were exposed to coal-derived syngas, and the impact of coal-derived impurities was evaluated. This report summarizes the performance of WRI’s patent-pending coalupgrading/ gasification technology in the EERC’s TRDU and presents the results of the warm-gas cleanup and hydrogen separation tests. Overall, the WRI coal-upgrading/gasification technology was shown to produce a syngas significantly lower in CO2 content and significantly higher in CO content than syngas produced from the raw fuels. Warm-gas cleanup technologies were shown to be capable of reducing sulfur in the syngas to 1 ppm. Each of the membranes tested was able to produce at least 2 lb/day of hydrogen from coal-derived syngas

Subtask 3.4 - Fischer - Tropsch Fuels Development

Under Subtask 3.4, the Energy & Environmental Research Center (EERC) examined the opportunities and challenges facing FischerâTropsch (FT) technology in the United States today. Work was completed in two distinct budget periods (BPs). In BP1, the EERC examined the technical feasibility of using modern warm-gas cleanup techniques for FT synthesis. FT synthesis is typically done using more expensive and complex cold-gas sweetening. Warm-gas cleanup could greatly reduce capital and operating costs, making FT synthesis more attractive for domestic fuel production. Syngas was generated from a variety of coal and biomass types; cleaned of sulfur, moisture, and condensables; and then passed over a pilot-scale FT catalyst bed. Laboratory and modeling work done in support of the pilot-scale effort suggested that the catalyst was performing suboptimally with warm-gas cleanup. Long-term trends showed that the catalyst was also quickly deactivating. In BP3, the EERC compared FT catalyst results using warm-gas cleanup to results using cold-gas sweetening. A gas-sweetening absorption system (GSAS) was designed, modeled, and constructed to sweeten syngas between the gasifier and the pilot-scale FT reactor. Results verified that the catalyst performed much better with gas sweetening than it had with warm-gas cleanup. The catalyst also showed no signs of rapid deactivation when the GSAS was running. Laboratory tests in support of this effort verified that the catalyst had deactivated quickly in BP1 because of exposure to syngas, not because of any design flaw with the pilot-scale FT reactor itself. Based on these results, the EERC concludes that the two biggest issues with using syngas treated with warm-gas cleanup for FT synthesis are high concentrations of CO{sub 2} and volatile organic matter. Other catalysts tested by the EERC may be more tolerant of CO{sub 2}, but volatile matter removal is critical to ensuring long-term FT catalyst operation. This subtask was funded through the EERCâU.S. Department of Energy (DOE) Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding for BP1 was provided by the North Dakota Industrial Commissionâs (NDIC) Renewable Energy Council

Subtask 3.4 - Fischer - Tropsch Fuels Development

Under Subtask 3.4, the Energy & Environmental Research Center (EERC) examined the opportunities and challenges facing FischerâTropsch (FT) technology in the United States today. Work was completed in two distinct budget periods (BPs). In BP1, the EERC examined the technical feasibility of using modern warm-gas cleanup techniques for FT synthesis. FT synthesis is typically done using more expensive and complex cold-gas sweetening. Warm-gas cleanup could greatly reduce capital and operating costs, making FT synthesis more attractive for domestic fuel production. Syngas was generated from a variety of coal and biomass types; cleaned of sulfur, moisture, and condensables; and then passed over a pilot-scale FT catalyst bed. Laboratory and modeling work done in support of the pilot-scale effort suggested that the catalyst was performing suboptimally with warm-gas cleanup. Long-term trends showed that the catalyst was also quickly deactivating. In BP3, the EERC compared FT catalyst results using warm-gas cleanup to results using cold-gas sweetening. A gas-sweetening absorption system (GSAS) was designed, modeled, and constructed to sweeten syngas between the gasifier and the pilot-scale FT reactor. Results verified that the catalyst performed much better with gas sweetening than it had with warm-gas cleanup. The catalyst also showed no signs of rapid deactivation when the GSAS was running. Laboratory tests in support of this effort verified that the catalyst had deactivated quickly in BP1 because of exposure to syngas, not because of any design flaw with the pilot-scale FT reactor itself. Based on these results, the EERC concludes that the two biggest issues with using syngas treated with warm-gas cleanup for FT synthesis are high concentrations of CO{sub 2} and volatile organic matter. Other catalysts tested by the EERC may be more tolerant of CO{sub 2}, but volatile matter removal is critical to ensuring long-term FT catalyst operation. This subtask was funded through the EERCâU.S. Department of Energy (DOE) Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291. Nonfederal funding for BP1 was provided by the North Dakota Industrial Commissionâs (NDIC) Renewable Energy Council

Effect of electric load and dual atmosphere on the properties of an alkali containing diopside-based glass sealant for solid oxide cells

© 2019 Elsevier B.V. All rights reserved.A new alkali-containing diopside based glass-ceramic sealant for solid oxide cells was synthesized, characterized and tested. The composition was designed to match the coefficient of thermal expansion (CTE) of Crofer22APU interconnect. The sealant has a glass transition temperature of 600°C, a crystallization peak temperature of 850°C and a maximum shrinkage temperature of 700°C, thus suggesting effective densification prior to crystallization. The CTE of the glass-ceramic is 11.5 10-6 K-1, a value which is compatible with the CTE for Crofer22APU stainless steel. Crofer22APU/glass-ceramic/Crofer22APU joined samples were tested in simulated real-life operating conditions at 800°C in dual atmosphere under an applied voltage, monitoring the electrical resistivity. The effect of two different applied voltages (0.7V and 1.3V) was evaluated. A voltage of 1.3V led to a rapid decrease in the electrical resistivity during the test;such a drop was due to the formation of Cr2O3 “bridges” that connected the two Crofer22APU plates separated by the sealant. There was no decrease in the resistivity when a voltage of 0.7V was applied. Instead,resistivity value remained stable at around 105 Ω cm for the 100h test duration. The degradation mechanisms, due to both the alkali content and the applied voltage, are investigated and discussed.Peer reviewe

Информационная система заказа, обслуживания и мониторинга доставки продукции в пределах городской черты

В работе рассматриваются программные компоненты информационной системы доставки: заказ продукции широкого потребительского профиля в магазинах города с возможностью определения магазина по требуемой клиентом продукции, обслуживание доставки продавцом и курьером, а также мониторинг процесса доставки заказа клиентом. Система состоит из серверной (программный интерфейс приложения, база данных, сервис кэширования) и клиентской части (мобильное и веб-приложение).The study considers the software components of the delivery information system: ordering products of a wide consumer profile in city stores with the ability to determine the store for the products required by the client, delivery service by the seller and courier, as well as monitoring the process of order delivery by the client. The system consists of a server (application programming interface, database, caching service) and a client (mobile and web application)

Using e-learning to support international students' dissertation preparation

Purpose: A research paper on the design and implementation of an e-learning resource responding to the globalisation of education. The purpose of this paper is to focus on the challenges presented in learning and teaching on how to support international postgraduate (PG) students undertaking the specific task of a dissertation. Design/methodology/approach: Using findings from 250 PG students, 40 supervisors and two module tutors the research identified the content and language issues faced by students and recognised the need to design an enabler supporting the latter as independent learners and the academic staff delivering support. Findings: The e-learning tool provides an independent learning tool which addresses student concerns relating to the process and content of structuring a dissertation and the function of language. Initial responses have been positive from both staff and students in respect to providing a source of student support and feedback. Originality/value: The research shows how the Dissertation Game Model (DGM), evolved into an e-learning resource supporting student understanding of the content, structure, planning and writing of a dissertation. The e-learning tool focuses on helping international students understand what the generic contents of each chapter of a dissertation should contain and supports them in engaging in research as a transferable skill