346 research outputs found
Redox Pioneer: Professor Regina Brigelius-Flohé
No full textDr. Regina Brigelius-Flohe (PhD 1978) is recognized here as redox pioneer because she has published an article on redox biology, as first author, that has been cited >1000 times, plus four articles cited >500 times, and a total of 30 articles cited >100 times. She obtained her doctorate in biochemistry at the Institute of Biochemistry of the University of Munster, Germany. She held positions in both, academia (Munster, Munich, Dusseldorf, Hannover, and Potsdam, Germany) and industry (Aachen, Germany). Dr. Brigelius-Flohe is the pioneer who, as head of the department of biochemistry of micronutrients of the German Institute of Human Nutrition (DIfE; Potsdam-Rehbrucke, Germany), worked out the metabolism of tocopherols and tocotrienols ("Key Finding 1"). She was the first to sequence glutathione peroxidase 4 (GPx4) ("Key Finding 2"), and unraveled the role of selenium, in particular of GPxs, in inflammation and carcinogenesis ("Key Finding 3"). Her contributions, thus, focused on serious biomedical problems such as nutrition, inflammation, and carcinogenesis. She has been a member of the scientific advisory board of the German Society of Biochemistry and Molecular Biology for 6 years and was president of SFRR-Europe in 2005-2006. She edited several books and serves on the editorial board of journals in the fields of nutrition, free radicals, and redox regulation. Antioxid. Redox Signal. 35, 000-000
Utilization of Thorium in PWR reactors : first step toward a Th-U fuel cycle
No full textSince the beginning of Nuclear Energy Development, thorium was considered as a potential fuel, mainly due to the potential to produce fissile 233U. Several Th/U fuel cycles, using thermal and fast reactors were proposed and are still under investigation. However, the technical feasibilty to use thorium was made in PWR; the USA PWR Indian Point Reactor was the first to utilize a core load with (Th0-0.9./U1-0.1)O2, with highly enriched U (93w/0), achieving a maximum burn up of 32 MWD/kg HM. Also the last core of the Shipping port PWR (shutdown in 1982) was ThO2 and (Th/U)O2, operating as a Light Water Breeder Reactor (Seed-Blanket Concept) during 1200 effective full power days of operation (60 MWD/kg HM). More recently, many researchers turned their attention to Th fuel cycles in PWRs aiming at reducing the generation of minor actinide waste, at improving the nuclear power sustainability and at better fuel utilization. These studies were interested in assessing the feasibility of using 233U-Th fuels in PWR without worrying about how to obtain the initial 233U fuel load or the transition from an uranium to a thorium core in the current nuclear power plants. In this paper a review is provided of recent initiatives, with emphasis in a study, demonstrating the feasilibility to convert an existing advanced PWR (AP 1000) from UO2 to a mixed U/ThO2 core. The study takes as criterion that the transition from the current UO2 AP 1000 core to one with mixed U/Th fuels should be such that minimum changes occur on its current core design and operational parameters. Thus one could consider the following requirements in this study: produce important amounts of 233U (maximization) for future 233U/Th cores; keep the current fuel assembly geometry, i.e., fuel rod diameter and pitch and meet the current thermal-hydraulic limits such as maximum center line fuel rod temperature and maximum linear power density; keep the current fuel cycle length of 18 months. The results obtained showed that the homogeneous concept with three different mass proportion zones, the first containing (32% UO2-68%ThO2); the second with (24% UO2-76% ThO2), and the third with (20% UO2-80% ThO2), using 235U LEU (20 w/o), and corresponding with the three enrichment zones of the AP 1000 (4.45 w/o; 3.40 w/o; 2.35 w/o), satisfies the optimization criteria as well as attending all thermal constraints. The concept showed advantages compared with the original UO2 core, such a lower power density and, keeping the same 18-months-cycle, a reduction of B-10 concentration as soluble poison, as well as eliminating the integral boron poison coated (IFBA)
Refrigerated Transport: State of the Art, Technical Issues, Innovations and Challenges for Sustainability
No full textThe cold chain is responsible for perishable products preservation and transportation, maintaining a proper temperature to slow biological decay processes. Often the efficiency of the cold chain is less than ideal, significantly increasing food waste and energy consumption. Refrigerated transport is a critical phase of the cold chain because of its negative impact on energy consumption and greenhouse gas emissions. It is estimated that around 15% of global fossil fuel energy is used in the refrigerated transport sector, so there has been a growing interest in the last decades in the optimization of these systems in order to reduce their environmental impact. Vapor compression refrigeration units, usually powered by means of a diesel engine, are the most commonly used systems in road refrigerated transport. This paper provides a review of (a) currently used systems and alternative technologies that could reduce the environmental impacts of road refrigerated transport and (b) optimization models and methods used to minimize fuel/energy consumption and greenhouse gas emissions, focusing both on reducing the thermal loads and solving the refrigerated vehicle routing problem
Redox Pioneer: Professor Leopold Flohe
No full textLeopold Flohé is recognized here as a Redox Pioneer because has published a article on antioxidant/redox biology, as first author, that has been cited more than 1,000 times, and more than 20 articles have been cited more than 100 times. He obtained the medical doctorate at the Institute of Pharmacology and Toxicology at the University of Tübingen, Germany, in 1968. He held positions in both Academia (Tübingen, Aachen, and Braunschweig, Germany) and industry (Aachen). He is now operating the biotech company MOLISA in Magdeburg, Germany, while teaching as guest professor at the local university. Dr. Flohé is the pioneer who established the selenoprotein nature of glutathione peroxidase (GPx), the first and, for almost 10 years, the only selenoprotein known in animals. His work was pivotal to link the essential trace element selenium to metabolic processes, which led the Food and Drug Administration (FDA) to approve selenium supplementation for humans in 1980, and stimulated selenium biochemistry in general. In recent years, he embarked on investigating how pathogens protect themselves from oxidative killing. His inseminating studies on the thiol-dependent hydroperoxide metabolism of trypanosomatids and mycobacteria defined molecular drug targets, paving the way to new therapeutic strategies for neglected diseases affecting the people of developing countries
Functional interaction of phospholid hydroperoxide glutathione peroxidase with sperm mitochondrion-associated cysteine-rich protein discloses the adjacent cysteine motif as a new substrate of the Se-peroxidase.
Get PDFThe mitochondrial capsule is a selenium- and disulfide-rich structure enchasing the outer mitochondrial membrane of mammalian spermatozoa. Among the proteins solubilized from the sperm mitochondrial capsule, we confirmed, by using a proteomic approach, the presence of phospholipid hydroperoxide glutathione peroxidase (PHGPx) as a major component, and we also identified the sperm mitochondrion-associated cysteine-rich protein ( SMCP) and fragments/aggregates of specific keratins that previously escaped detection (Ursini, F., Heim, S., Kiess, M., Maiorino, M., Roveri, A., Wissing, J., and Flohe ', L. ( 1999) Science 285, 1393 - 1396). The evidence for a functional association between PHGPx, SMCP, and keratins is further supported by the identification of a sequence motif of regularly spaced Cys-Cys doublets common to SMCP and high sulfur keratin-associated proteins, involved in bundling hair shaft keratin by disulfide cross-linking. Following the oxidative polymerization of mitochondrial capsule proteins, catalyzed by PHGPx, two-dimensional redox electrophoresis analysis showed homo- and heteropolymers of SMCP and PHGPx, together with other minor components. Adjacent cysteine residues in SMCP peptides are oxidized to cystine by PHGPx. This unusual disulfide is known to drive, by reshuffling oxidative protein folding. On this basis we propose that oxidative polymerization of the mitochondrial capsule is primed by the formation of cystine on SMCP, followed by reshuffling. Occurrence of reshuffling is further supported by the calculated thermodynamic gain of the process. This study suggests a new mechanism where selenium catalysis drives the cross-linking of structural elements of the cytoskeleton via the oxidation of a keratin-associated protein
L'archivio messo in opera, nuove riflessioni su Carlo Alfano
No full textLa “forma” e la pratica dell’archivio appaiono come elementi ricorsivi dell’originale sintassi creativa di Carlo Alfano. In esse l’artista trova un momento fondamentale della sua ricerca e al tempo stesso il viatico di una prassi antiautoritaria. Il saggio si propone di rispondere ad alcune domande essenziali: quando e in che modo il tema dell’archivio assume caratteri generativi nella ricerca di Alfano e da qui quali strategie compositive vengono messe in atto nel solco della dispersione, ovvero dopo che il pensiero di Michel Foucault apre una breccia emancipativa nell’orizzonte eminentemente percettivo frequentato dall’artista per buona parte degli anni sessanta
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