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Oxidative stress: the lowest common denominator of multiple diseases

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Neural Regeneration Research 2019年第2期14卷 238-241页

作者： Veronika Matschke carsten Theiss Johann Matschke Institute of Anatomy Department of Cytology Ruhr University Bochum Institute of Cell Biology (Cancer Research) University of Duisburg-Essen University Hospital Essen

Oxygen is essential to the human life and life of all aerobic organisms. The complete oxidation of nutrients for the biological energy supply is one of the most important prerequisites for the formation of higher life forms. However, cells that benefit from oxidative respiration also suffer from reactive oxygen species because they adapted to oxygen as an energy source. Healthy cells balance the formation and elimination of reactive oxygen species thereby creating and keeping reactive oxygen species-homeostasis. When the concentration of free radicals exceeds a critical level and homeostasis is disturbed, oxidative stress occurs leading to damage of multiple cellular molecules and compartments. Therefore, oxidative stress plays an important role in the physiology and pathology of various diseases. Often, the antioxidant protection system becomes pathologically unbalanced in the genesis of several diseases, leading to functional losses of the organism, as in the case of amyotrophic lateral sclerosis, or cells develop metabolic mechanisms to use this system as protection against external influences, such as in the case of glioblastoma cells. Either way, understanding the underlying deregulated mechanisms of the oxidative protection system would allow the development of novel treatment strategies for various diseases. Thus, regardless of the direction in which the reactive oxygen species-homeostasis disequilibrate, the focus should be on the oxidative protection system.

关键词： neurodegenerative disease amyotrophic lateral sclerosis cancer glioblastoma reactive oxygen species metabolism antioxidant protection system

MULTIGRID METHODS FOR OBSTACLE PROBLEMS

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Journal of Computational Mathematics 2009年第1期27卷 1-44页

作者： carsten Grser Ralf Kornhuber Freie Universitt Berlin Institut für Mathematik

In this review, we intend to clarify the underlying ideas and the relations between various multigrid methods ranging from subset decomposition, to projected subspace decomposition and truncated multigrid. In addition, we present a novel globally convergent inexact active set method which is closely related to truncated multigrid. The numerical properties of algorithms are carefully assessed by means of a degenerate problem and a problem with a complicated coincidence set.

关键词： Multigrid methods Variational inequalities.

Nafion/polypyrrole and Nafion/DMSO Organic Coatings for Magnesium Protection

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Journal of Materials Science & Technology 2007年第1期23卷 139-141页

作者： Renguo SONG Xiaohua ZHENG carsten Blawer Wolfgang Dietzel The MOE Key Laboratory of Mechanical Manufacture and Automation Zhejiang University of Technology Hangzhou 310014 China Center for Magnesium Technology Institute of Materials Research GKSS-Forschungszentrum Geesthacht GmbH Max-Planck Straβe 1 D-21502 Geesthacht Germany

Nafion/polypyrrole and Nafion/Dimethysulfoxid （DMSO） organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.

关键词： Magnesium Naflon/polypyrrole organic coatings Naflon/DMSO organic coatings Corrosion resistance

An Analysis on Decentralized Adaptive MAC Protocols for Cognitive Radio Networks

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International Journal of Automation and computing 2013年第1期10卷 46-52页

作者： Munam Ali Shah Sijing Zhang carsten Maple Department of Computer Science and Technology Institute of Research in Applicable Computing University of Bedfordshire

The scarcity of bandwidth in the radio spectrum has become more vital since the demand for more and more wireless applications has increased. Most of the spectrum bands have been allocated although many studies have shown that these bands are significantly underutilized most of the time. The problem of unavailability of spectrum and inefficiency in its utilization has been smartly addressed by the cognitive radio （CR） technology which is an opportunistic network that senses the environment, observes the network changes, and then uses knowledge gained from the prior interaction with the network to make intelligent decisions by dynamically adapting their transmission characteristics. In this paper, some of the decentralized adaptive medium access control （MAC） protocols for CR networks have been critically analyzed, and a novel adaptive MAC protocol for CR networks, decentralized non-global MAC （DNG-MAC）, has been proposed. The results show the DNG-MAC outperforms other CR-MAC protocols in terms of time and energy efficiency.

关键词： Cognitive radio medium access control (MAC) protocols common control channel cooperative communication

Development of open-porosity magnesium foam produced by investment casting

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Journal of Magnesium and Alloys 2022年第7期10卷 1941-1956页

作者： Honorata Kapłon carsten Blawert Jacek Ch˛ecmanowski Krzysztof Naplocha Faculty of Mechanical Engineering Wrocław University of Science and TechnologyUl.Smoluchowskiego 25Wrocław 50-370Poland Institute of Surface Science Helmholtz-Zentrum GeesthachtMax-Planck-Straβe 1Geesthacht21502Germany Faculty of Chemistry Wrocław University of Science and TechnologyWybrze˙ze Stanisława Wyspia´nskiego 27Wrocław50-370Poland

High-porosity,open-cell AZ91 magnesium alloy foams of two pore sizes were fabricated by means of investment casting technology,using PUR foam *** casting variables such as pressure,mould temperature and metal pouring temperature were thoroughly investigated to define the most optimal casting *** mechanical properties of the fabricated foams were measured in compression tests.A potential application for the foams considered is temporary bioresorbable bone implants,therefore the mechanical properties of the foams were compared with those of cancellous bone *** with smaller pore size and lower porosity(20 PPI and 80%±87%)exhibited mechanical properties in the lower regions of the cancellous bone property range(Young’s modulus 36.5±77.5 MPa),while foams with higher pore size and porosity(10 PPI and~90%)were found to have insufficient compression strength(Young’s modulus 11.65±23.8),but thickening their walls and lowering their porosity below 90%yielded foams with Young’s modulus between 36.5 and 77.5 *** fractures were also investigated to determine their collapse mechanism.A series of corrosion tests in stimulated body fluid was carried out to determine their applicability as a *** Plasma Electrolytic Oxidation(PEO)process was used in a feasibility study to examine the microstructure and chemical composition of foams with protective coating.

关键词： Magnesium foams AZ91 investment casting Bone implants Plasma electrolytic oxidation

Corrosion performance,corrosion fatigue behavior and mechanical integrity of an extruded Mg4Zn0.2Sn alloy

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Journal of Materials Science & Technology 2020年第24期59卷 107-116页

作者： Pingli Jiang carsten Blawert Jan Bohlen Mikhail L.Zheludkevich Magnesium Innovation Centre-MagIC Institute of Materials ResearchHelmholtz-Zentrum GeesthachtMax-Planck Str.1Geesthacht 21502Germany Faculty of Engineering University of KielKaiserstrasse 224143 KielGermany

Magnesium alloys are promising as load bearing *** are inevitably exposed to cyclic loading and corrosive environment in actual service,which can consequently result in corrosion fatigue failure and loss of mechanical integrity of the ***,in the present study,the corrosion behavior,corrosion fatigue performance and mechanical integrity of an extruded Mg4Zn0.2Sn(wt.%)alloy were thoroughly studied in two corrosive *** localized corrosion occurred when the alloy was immersed in deionized water based sodium chloride(NaCl)*** poor corrosion resistance of the alloy resulted in a fast deterioration of the tensile properties after pre-exposure to salt spray and a poor fatigue resistance in deionized water based NaCl *** comparison,the active dissolution of the substrate was sufficiently suppressed in artificial tap water based NaCl solution due to the formation of highly protective corrosion product *** consequently conferred longer fatigue life on the alloy in the *** results emphasized the influence of corrosion on the fatigue behavior and tensile properties of magnesium alloys.

关键词： Magnesium alloy Tin Artificial tap water Corrosion fatigue Mechanical integrity

Transition to Very High Share of Renewables in Germany

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CSEE Journal of Power and Energy Systems 2017年第1期3卷 17-25页

作者： carsten D.Ahrens Faculty of Civil Engineering and Geoinformation(BGG) University of Applied SciencesOldenburgGermany

The objective of this paper is to show that the German way towards renewable energy production could become an example for successful energy transition in other *** on the Renewable Energy Act(Erneuerbare Energien Gesetz(EEG))in the year 2000 the most important steps for this transition seemed to be start-ups with relevant and reliable feed-in tariffs,the involvement of“many single”intelligently and digitally connected producers to form a kind of“swarm-energy.”In addition regional smart grids,a national grid structure with sufficient capacity,and,last but not least,implementation of energy efficiency tools in the building,construction and transport sector,are necessary driving sources.

关键词： Digital future of(green)electricity electricity power mix energy transition grid reliability renewable energy swarm energy

Low-energy ion channeling in nanocubes

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Nano Research 2023年第1期16卷 1522-1526页

作者： Shiva Choupanian Wolfhard Möller Martin Seyring carsten Ronning Institute of Solid State Physics Friedrich Schiller University JenaMax-Wien-Platz 107743 JenaGermany Helmholtz-Zentrum Dresden-Rossendorf Bautzner Landstraße 40001328 DresdenGermany Otto Schott Institute of Materials Research Friedrich Schiller University JenaLoebdergraben 3207743 JenaGermany

Focused ion beam(FIB)processing with low-energy ions has become a standard technique for the manipulation of *** underlying ion beam effects that deviate from conventional high-energy ion irradiation of bulk systems are considered today;however,ion channeling with its consequence of significant deeper penetration depth has been only theoretically investigated in this *** present here an experimental approach to determine the channeling of low-energy ions in crystalline nanoparticles by measuring the sputter yield derived from scanning electron microscopy(SEM)images taken after irradiation under various incident ion *** maps of 30 and 20 keV Ga+ions in Ag nanocubes have been identified and fit well with the ***,channeling has a significant impact on the transport of energetic ions in crystals due to the large critical angle at low ion energies,thus being relevant for any ***,the obtained sputter yield clearly differs from amorphous materials;therefore,it is recommended not to rely only on,e.g.,ion distribution depths predicted by standard Monte-Carlo(MC)algorithms for amorphous materials.

关键词： ion nanostructure interaction ion channeling metallic nanoparticles focused ion beam

Oxygen tolerance capacity of upflow anaerobic solid-state(UASS) with anaerobic filter(AF) system

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Journal of Environmental Sciences 2016年第7期28卷 200-206页

作者： Yao Meng carsten Jost Jan Mumme Kaijun Wang Bernd Linke State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Department Bioengineering Leibniz Institute for Agricultural Engineering UK Biochar Centre School of Geo Sciences University of Edinburgh

In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state（UASS）with anaerobic filter（AF） system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen（DO） of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.

关键词： Anaerobic digestion Oxygen tolerance capacity UASS Maize straw Microaeration Solid-state