41 research outputs found

    Reversible and Irreversible Interactions of Poly(3-hexylthiophene) with Oxygen Studied by Spin-Sensitive Methods

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    Understanding of degradation mechanisms in polymer:fullerene bulk-heterojunctions on the microscopic level aimed at improving their intrinsic stability is crucial for the breakthrough of organic photovoltaics. These materials are vulnerable to exposure to light and/or oxygen, hence they involve electronic excitations. To unambiguously probe the excited states of various multiplicities and their reactions with oxygen, we applied combined magneto-optical methods based on multifrequency (9 and 275 GHz) electron paramagnetic resonance (EPR), photoluminescence (PL), and PL-detected magnetic resonance (PLDMR) to the conjugated polymer poly(3-hexylthiophene) (P3HT) and polymer:fullerene bulk heterojunctions (P3HT:PCBM; PCBM = [6,6]-phenyl-C61-butyric acid methyl ester). We identified two distinct photochemical reaction routes, one being fully reversible and related to the formation of polymer:oxygen charge transfer complexes, the other one, irreversible, being related to the formation of singlet oxygen under participation of bound triplet excitons on the polymer chain. With respect to the blends, we discuss the protective effect of the methanofullerenes on the conjugated polymer bypassing the triplet exciton generation

    Triplet Exciton Generation in Bulk-Heterojunction Solar Cells based on Endohedral Fullerenes

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    Organic bulk-heterojunctions (BHJ) and solar cells containing the trimetallic nitride endohedral fullerene 1-[3-(2-ethyl)hexoxy carbonyl]propyl-1-phenyl-Lu3N@C80 (Lu3N@C80-PCBEH) show an open circuit voltage (VOC) 0.3 V higher than similar devices with [6,6]-phenyl-C[61]-butyric acid methyl ester (PC61BM). To fully exploit the potential of this acceptor molecule with respect to the power conversion efficiency (PCE) of solar cells, the short circuit current (JSC) should be improved to become competitive with the state of the art solar cells. Here, we address factors influencing the JSC in blends containing the high voltage absorber Lu3N@C80-PCBEH in view of both photogeneration but also transport and extraction of charge carriers. We apply optical, charge carrier extraction, morphology, and spin-sensitive techniques. In blends containing Lu3N@C80-PCBEH, we found 2 times weaker photoluminescence quenching, remainders of interchain excitons, and, most remarkably, triplet excitons formed on the polymer chain, which were absent in the reference P3HT:PC61BM blends. We show that electron back transfer to the triplet state along with the lower exciton dissociation yield due to intramolecular charge transfer in Lu3N@C80-PCBEH are responsible for the reduced photocurrent

    Human Practice. Digital Ecologies. Our Future. : 14. Internationale Tagung Wirtschaftsinformatik (WI 2019) : Tagungsband

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    Erschienen bei: universi - UniversitĂ€tsverlag Siegen. - ISBN: 978-3-96182-063-4Aus dem Inhalt: Track 1: Produktion & Cyber-Physische Systeme Requirements and a Meta Model for Exchanging Additive Manufacturing Capacities Service Systems, Smart Service Systems and Cyber- Physical Systems—What’s the difference? Towards a Unified Terminology Developing an Industrial IoT Platform – Trade-off between Horizontal and Vertical Approaches Machine Learning und Complex Event Processing: Effiziente Echtzeitauswertung am Beispiel Smart Factory Sensor retrofit for a coffee machine as condition monitoring and predictive maintenance use case Stakeholder-Analyse zum Einsatz IIoT-basierter Frischeinformationen in der Lebensmittelindustrie Towards a Framework for Predictive Maintenance Strategies in Mechanical Engineering - A Method-Oriented Literature Analysis Development of a matching platform for the requirement-oriented selection of cyber physical systems for SMEs Track 2: Logistic Analytics An Empirical Study of Customers’ Behavioral Intention to Use Ridepooling Services – An Extension of the Technology Acceptance Model Modeling Delay Propagation and Transmission in Railway Networks What is the impact of company specific adjustments on the acceptance and diffusion of logistic standards? Robust Route Planning in Intermodal Urban Traffic Track 3: Unternehmensmodellierung & Informationssystemgestaltung (Enterprise Modelling & Information Systems Design) Work System Modeling Method with Different Levels of Specificity and Rigor for Different Stakeholder Purposes Resolving Inconsistencies in Declarative Process Models based on Culpability Measurement Strategic Analysis in the Realm of Enterprise Modeling – On the Example of Blockchain-Based Initiatives for the Electricity Sector Zwischenbetriebliche Integration in der Möbelbranche: Konfigurationen und Einflussfaktoren Novices’ Quality Perceptions and the Acceptance of Process Modeling Grammars Entwicklung einer Definition fĂŒr Social Business Objects (SBO) zur Modellierung von Unternehmensinformationen Designing a Reference Model for Digital Product Configurators Terminology for Evolving Design Artifacts Business Role-Object Specification: A Language for Behavior-aware Structural Modeling of Business Objects Generating Smart Glasses-based Information Systems with BPMN4SGA: A BPMN Extension for Smart Glasses Applications Using Blockchain in Peer-to-Peer Carsharing to Build Trust in the Sharing Economy Testing in Big Data: An Architecture Pattern for a Development Environment for Innovative, Integrated and Robust Applications Track 4: Lern- und Wissensmanagement (e-Learning and Knowledge Management) eGovernment Competences revisited – A Literature Review on necessary Competences in a Digitalized Public Sector Say Hello to Your New Automated Tutor – A Structured Literature Review on Pedagogical Conversational Agents Teaching the Digital Transformation of Business Processes: Design of a Simulation Game for Information Systems Education Conceptualizing Immersion for Individual Learning in Virtual Reality Designing a Flipped Classroom Course – a Process Model The Influence of Risk-Taking on Knowledge Exchange and Combination Gamified Feedback durch Avatare im Mobile Learning Alexa, Can You Help Me Solve That Problem? - Understanding the Value of Smart Personal Assistants as Tutors for Complex Problem Tasks Track 5: Data Science & Business Analytics Matching with Bundle Preferences: Tradeoff between Fairness and Truthfulness Applied image recognition: guidelines for using deep learning models in practice Yield Prognosis for the Agrarian Management of Vineyards using Deep Learning for Object Counting Reading Between the Lines of Qualitative Data – How to Detect Hidden Structure Based on Codes Online Auctions with Dual-Threshold Algorithms: An Experimental Study and Practical Evaluation Design Features of Non-Financial Reward Programs for Online Reviews: Evaluation based on Google Maps Data Topic Embeddings – A New Approach to Classify Very Short Documents Based on Predefined Topics Leveraging Unstructured Image Data for Product Quality Improvement Decision Support for Real Estate Investors: Improving Real Estate Valuation with 3D City Models and Points of Interest Knowledge Discovery from CVs: A Topic Modeling Procedure Online Product Descriptions – Boost for your Sales? EntscheidungsunterstĂŒtzung durch historienbasierte Dienstreihenfolgeplanung mit Pattern A Semi-Automated Approach for Generating Online Review Templates Machine Learning goes Measure Management: Leveraging Anomaly Detection and Parts Search to Improve Product-Cost Optimization Bedeutung von Predictive Analytics fĂŒr den theoretischen Erkenntnisgewinn in der IS-Forschung Track 6: Digitale Transformation und Dienstleistungen Heuristic Theorizing in Software Development: Deriving Design Principles for Smart Glasses-based Systems Mirroring E-service for Brick and Mortar Retail: An Assessment and Survey Taxonomy of Digital Platforms: A Platform Architecture Perspective Value of Star Players in the Digital Age Local Shopping Platforms – Harnessing Locational Advantages for the Digital Transformation of Local Retail Outlets: A Content Analysis A Socio-Technical Approach to Manage Analytics-as-a-Service – Results of an Action Design Research Project Characterizing Approaches to Digital Transformation: Development of a Taxonomy of Digital Units Expectations vs. Reality – Benefits of Smart Services in the Field of Tension between Industry and Science Innovation Networks and Digital Innovation: How Organizations Use Innovation Networks in a Digitized Environment Characterising Social Reading Platforms— A Taxonomy-Based Approach to Structure the Field Less Complex than Expected – What Really Drives IT Consulting Value Modularity Canvas – A Framework for Visualizing Potentials of Service Modularity Towards a Conceptualization of Capabilities for Innovating Business Models in the Industrial Internet of Things A Taxonomy of Barriers to Digital Transformation Ambidexterity in Service Innovation Research: A Systematic Literature Review Design and success factors of an online solution for cross-pillar pension information Track 7: IT-Management und -Strategie A Frugal Support Structure for New Software Implementations in SMEs How to Structure a Company-wide Adoption of Big Data Analytics The Changing Roles of Innovation Actors and Organizational Antecedents in the Digital Age Bewertung des Kundennutzens von Chatbots fĂŒr den Einsatz im Servicedesk Understanding the Benefits of Agile Software Development in Regulated Environments Are Employees Following the Rules? On the Effectiveness of IT Consumerization Policies Agile and Attached: The Impact of Agile Practices on Agile Team Members’ Affective Organisational Commitment The Complexity Trap – Limits of IT Flexibility for Supporting Organizational Agility in Decentralized Organizations Platform Openness: A Systematic Literature Review and Avenues for Future Research Competence, Fashion and the Case of Blockchain The Digital Platform Otto.de: A Case Study of Growth, Complexity, and Generativity Track 8: eHealth & alternde Gesellschaft Security and Privacy of Personal Health Records in Cloud Computing Environments – An Experimental Exploration of the Impact of Storage Solutions and Data Breaches Patientenintegration durch Pfadsysteme Digitalisierung in der StressprĂ€vention – eine qualitative Interviewstudie zu Nutzenpotenzialen User Dynamics in Mental Health Forums – A Sentiment Analysis Perspective Intent and the Use of Wearables in the Workplace – A Model Development Understanding Patient Pathways in the Context of Integrated Health Care Services - Implications from a Scoping Review Understanding the Habitual Use of Wearable Activity Trackers On the Fit in Fitness Apps: Studying the Interaction of Motivational Affordances and Users’ Goal Orientations in Affecting the Benefits Gained Gamification in Health Behavior Change Support Systems - A Synthesis of Unintended Side Effects Investigating the Influence of Information Incongruity on Trust-Relations within Trilateral Healthcare Settings Track 9: Krisen- und KontinuitĂ€tsmanagement Potentiale von IKT beim Ausfall kritischer Infrastrukturen: Erwartungen, Informationsgewinnung und Mediennutzung der Zivilbevölkerung in Deutschland Fake News Perception in Germany: A Representative Study of People’s Attitudes and Approaches to Counteract Disinformation Analyzing the Potential of Graphical Building Information for Fire Emergency Responses: Findings from a Controlled Experiment Track 10: Human-Computer Interaction Towards a Taxonomy of Platforms for Conversational Agent Design Measuring Service Encounter Satisfaction with Customer Service Chatbots using Sentiment Analysis Self-Tracking and Gamification: Analyzing the Interplay of Motivations, Usage and Motivation Fulfillment Erfolgsfaktoren von Augmented-Reality-Applikationen: Analyse von Nutzerrezensionen mit dem Review-Mining-Verfahren Designing Dynamic Decision Support for Electronic Requirements Negotiations Who is Stressed by Using ICTs? A Qualitative Comparison Analysis with the Big Five Personality Traits to Understand Technostress Walking the Middle Path: How Medium Trade-Off Exposure Leads to Higher Consumer Satisfaction in Recommender Agents Theory-Based Affordances of Utilitarian, Hedonic and Dual-Purposed Technologies: A Literature Review Eliciting Customer Preferences for Shopping Companion Apps: A Service Quality Approach The Role of Early User Participation in Discovering Software – A Case Study from the Context of Smart Glasses The Fluidity of the Self-Concept as a Framework to Explain the Motivation to Play Video Games Heart over Heels? An Empirical Analysis of the Relationship between Emotions and Review Helpfulness for Experience and Credence Goods Track 11: Information Security and Information Privacy Unfolding Concerns about Augmented Reality Technologies: A Qualitative Analysis of User Perceptions To (Psychologically) Own Data is to Protect Data: How Psychological Ownership Determines Protective Behavior in a Work and Private Context Understanding Data Protection Regulations from a Data Management Perspective: A Capability-Based Approach to EU-GDPR On the Difficulties of Incentivizing Online Privacy through Transparency: A Qualitative Survey of the German Health Insurance Market What is Your Selfie Worth? A Field Study on Individuals’ Valuation of Personal Data Justification of Mass Surveillance: A Quantitative Study An Exploratory Study of Risk Perception for Data Disclosure to a Network of Firms Track 12: Umweltinformatik und nachhaltiges Wirtschaften KommunikationsfĂ€den im Nadelöhr – Fachliche Prozessmodellierung der Nachhaltigkeitskommunikation am Kapitalmarkt Potentiale und Herausforderungen der Materialflusskostenrechnung Computing Incentives for User-Based Relocation in Carsharing Sustainability’s Coming Home: Preliminary Design Principles for the Sustainable Smart District Substitution of hazardous chemical substances using Deep Learning and t-SNE A Hierarchy of DSMLs in Support of Product Life-Cycle Assessment A Survey of Smart Energy Services for Private Households Door-to-Door Mobility Integrators as Keystone Organizations of Smart Ecosystems: Resources and Value Co-Creation – A Literature Review Ein EntscheidungsunterstĂŒtzungssystem zur ökonomischen Bewertung von Mieterstrom auf Basis der Clusteranalyse Discovering Blockchain for Sustainable Product-Service Systems to enhance the Circular Economy Digitale RĂŒckverfolgbarkeit von Lebensmitteln: Eine verbraucherinformatische Studie Umweltbewusstsein durch audiovisuelles Content Marketing? Eine experimentelle Untersuchung zur Konsumentenbewertung nachhaltiger Smartphones Towards Predictive Energy Management in Information Systems: A Research Proposal A Web Browser-Based Application for Processing and Analyzing Material Flow Models using the MFCA Methodology Track 13: Digital Work - Social, mobile, smart On Conversational Agents in Information Systems Research: Analyzing the Past to Guide Future Work The Potential of Augmented Reality for Improving Occupational First Aid Prevent a Vicious Circle! The Role of Organizational IT-Capability in Attracting IT-affine Applicants Good, Bad, or Both? Conceptualization and Measurement of Ambivalent User Attitudes Towards AI A Case Study on Cross-Hierarchical Communication in Digital Work Environments ‘Show Me Your People Skills’ - Employing CEO Branding for Corporate Reputation Management in Social Media A Multiorganisational Study of the Drivers and Barriers of Enterprise Collaboration Systems-Enabled Change The More the Merrier? The Effect of Size of Core Team Subgroups on Success of Open Source Projects The Impact of Anthropomorphic and Functional Chatbot Design Features in Enterprise Collaboration Systems on User Acceptance Digital Feedback for Digital Work? Affordances and Constraints of a Feedback App at InsurCorp The Effect of Marker-less Augmented Reality on Task and Learning Performance Antecedents for Cyberloafing – A Literature Review Internal Crowd Work as a Source of Empowerment - An Empirical Analysis of the Perception of Employees in a Crowdtesting Project Track 14: GeschĂ€ftsmodelle und digitales Unternehmertum Dividing the ICO Jungle: Extracting and Evaluating Design Archetypes Capturing Value from Data: Exploring Factors Influencing Revenue Model Design for Data-Driven Services Understanding the Role of Data for Innovating Business Models: A System Dynamics Perspective Business Model Innovation and Stakeholder: Exploring Mechanisms and Outcomes of Value Creation and Destruction Business Models for Internet of Things Platforms: Empirical Development of a Taxonomy and Archetypes Revitalizing established Industrial Companies: State of the Art and Success Principles of Digital Corporate Incubators When 1+1 is Greater than 2: Concurrence of Additional Digital and Established Business Models within Companies Special Track 1: Student Track Investigating Personalized Price Discrimination of Textile-, Electronics- and General Stores in German Online Retail From Facets to a Universal Definition – An Analysis of IoT Usage in Retail Is the Technostress Creators Inventory Still an Up-To-Date Measurement Instrument? Results of a Large-Scale Interview Study Application of Media Synchronicity Theory to Creative Tasks in Virtual Teams Using the Example of Design Thinking TrustyTweet: An Indicator-based Browser-Plugin to Assist Users in Dealing with Fake News on Twitter Application of Process Mining Techniques to Support Maintenance-Related Objectives How Voice Can Change Customer Satisfaction: A Comparative Analysis between E-Commerce and Voice Commerce Business Process Compliance and Blockchain: How Does the Ethereum Blockchain Address Challenges of Business Process Compliance? Improving Business Model Configuration through a Question-based Approach The Influence of Situational Factors and Gamification on Intrinsic Motivation and Learning Evaluation von ITSM-Tools fĂŒr Integration und Management von Cloud-Diensten am Beispiel von ServiceNow How Software Promotes the Integration of Sustainability in Business Process Management Criteria Catalog for Industrial IoT Platforms from the Perspective of the Machine Tool Industry Special Track 3: Demos & Prototyping Privacy-friendly User Location Tracking with Smart Devices: The BeaT Prototype Application-oriented robotics in nursing homes Augmented Reality for Set-up Processe Mixed Reality for supporting Remote-Meetings Gamification zur Motivationssteigerung von Werkern bei der Betriebsdatenerfassung Automatically Extracting and Analyzing Customer Needs from Twitter: A “Needmining” Prototype GaNEsHA: Opportunities for Sustainable Transportation in Smart Cities TUCANA: A platform for using local processing power of edge devices for building data-driven services Demonstrator zur Beschreibung und Visualisierung einer kritischen Infrastruktur Entwicklung einer alltagsnahen persuasiven App zur Bewegungsmotivation fĂŒr Ă€ltere Nutzerinnen und Nutzer A browser-based modeling tool for studying the learning of conceptual modeling based on a multi-modal data collection approach Exergames & Dementia: An interactive System for People with Dementia and their Care-Network Workshops Workshop Ethics and Morality in Business Informatics (Workshop Ethik und Moral in der Wirtschaftsinformatik – EMoWI’19) Model-Based Compliance in Information Systems - Foundations, Case Description and Data Set of the MobIS-Challenge for Students and Doctoral Candidates Report of the Workshop on Concepts and Methods of Identifying Digital Potentials in Information Management Control of Systemic Risks in Global Networks - A Grand Challenge to Information Systems Research Die Mitarbeiter von morgen - Kompetenzen kĂŒnftiger Mitarbeiter im Bereich Business Analytics Digitaler Konsum: Herausforderungen und Chancen der Verbraucherinformati

    Optisch detektierte Magnetresonanz an organischen und anorganischen kohlenstoffbasierten Halbleitern

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    In dieser Arbeit werden drei verschiedene kohlenstoffbasierte Materialsysteme behandelt: (i) Organische Halbleiter und kleine MolekĂŒle, in Kombination mit Fullerenen fĂŒr Anwendungen in der organischen Photovoltaik (OPV), (ii) Halbleitende Einzelwand-Kohlenstoffnanoröhren und (iii) Siliziumkarbid (SiC), dessen Defekte erst seit kurzem als Kandidaten fĂŒr Quantenapplikationen gehandelt werden. Alle Systeme wurden mit optisch detektierter Magnetresonanzspektroskopie (ODMR) untersucht. Im OPV-Kapitel, die intrinsischen Parameter und Orientierungen von Exzitonen mit hohem Spin wurden fĂŒr die Materialsysteme P3HT, PTB7 und DIP untersucht. Speziell der Einfluss von Ordnung diesen organischen Systemen wurde diskutiert. Der zweite Teil des Kapitels beschĂ€ftigt sich mit Triplettgeneration mittels ElektronenrĂŒcktransfer im leistungsfĂ€higen Materialsystem PTB7:PC71BM. Das Kohlenstoffnanoröhren-Kapitel zeigt zuert den ersten zweifelsfreien Nachweis von Triplettexzitonen in halbleitenden (6,5) Einzelwandkohlenstoffnanoröhren (SWNT), mittels ODMR-Spektroskopie. Ein Modell fĂŒr die Anregungskinetik, die intrinsischen Parameter des Exzitons und AbhĂ€ngigkeit von der Orientierung der Röhren wurden diskutiert. Der letzte Teil der Arbeit gilt Spinzentren in Siliziumkarbid. Nach einer kurzen EinfĂŒhrung in das Materialsystem wird die SpinmultiplizitĂ€t fĂŒr die V2 und V3 Siliziumfehlstellen, sowie eines Frenkelpaars und eines noch nicht zugeordneten Defekts (UD) in 6H SiC, weiterhin fĂŒr die V2 Fehlstelle und das Frenkelpaar in 4H SiC, durchgĂ€ngig zu S=3/2 festgestellt. Das spinpolarisierte BefĂŒllen der 3/2-ZustĂ€nde des Grundzustands der Siliziumfehlstellen erlaubt stimulierte Mikrowellenemission. Ausserdem wurde fĂŒr UD und Frenkelpaar in 6H SiC eine große TemperaturabhĂ€ngigkeit der Nullfeldparameter festgestellt, wĂ€hrend die Siliziumfehlstellen temperaturunabhĂ€ngig sind. Anwendung des UD und Frenkelpaars als Temperatursensor, und der Vakanzen als Vektormagnetometer wurden diskutiert.In this work, three different material systems comprising carbon were researched: (i) Organic polymers and small molecules, in conjunction with fullerene molecules for applications in organic photovoltaics (OPV), (ii) single walled semiconducting carbon nanotubes and (iii) silicon carbide (SiC), whose defect color centers are recently in the limelight as candidates for quantum applications. All systems were analyzed using the optically detected magnetic resonance (ODMR) spectroscopy. In the OPV chapter, first the intrinsic parameters and orientations of high spin excitons were analyzed in the materials P3HT, PTB7 and DIP. Specifically the influence of ordering in these organic systems was adressed. The second part of the OPV chapter is concerned with triplet generation by electron back transfer in the high-efficiency OPV material combination PTB7:PC71BM. The carbon nanotube chapter first shows the way to the first unambiguous proof of the existence of triplet excitons in semiconducting (6,5) single-walled carbon nanotubes (SWNT) by ODMR spectroscopy. A model for exciton kinetics, and also orientation and intrinsic parameters were propoesed. The last part of this work is devoted to spin centers in silicon carbide (SiC). After a brief introduction, the spin multiplicity of the V2 and V3 silicon vacancies, and also of a Frenkel pair and an unassigned defect UD in 6H SiC, and of the V2 vacancy and the Frenkel pair in 4H SiC, was shown to be S=3/2. The spin polarized pumping of the 3/2 manifold of the quartet ground state of the silicon vacancies allows stimulated microwave emission. Furthermore, in 6H SiC, the UD and Frenkel pair were shown to have a large dependence of their intrinsic zero field interaction parameters on the temperature, while the vacancies are temperature independent. The application of the UD and Frenkel pair as temperature sensor, and of the vacancies as a vector magnetic field sensor is discussed

    Wirkung von Hyperthermie und ionisierender Strahlung auf Fibroblasten, Lymphozyten und lymphoblastoide Zellen

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    1.1. Hintergrund und Ziele Schon im 18. Jhd. machte man sich bei Behandlungen von Tumorerkrankungen den Effekt von WĂ€rme zu Nutze. Dies basierte damals vor allem auf der Induktion von Fieber. Die genauen Mechanismen der Hyperthermie sind bis heute aufgrund der vielzĂ€hligen Angriffspunkte nicht vollstĂ€ndig geklĂ€rt. Proteindenaturierung und Radiosensibilisierung sind hĂ€ufig nachgewiesene Effekte, die in dieser Arbeit verifiziert wurden. Die Folgen des thermischen Schadens sind vor allem bei Tumorzellen erforscht, jedoch gibt es wenige Daten ĂŒber gesunde Zelllinien wie Fibroblasten, Lymphozyten oder auch lymphoblastoide Zellen. In der vorliegenden Dissertation werden deshalb die vorzeitige Alterung der Zellen, Seneszenz genannt, sowie die Zelltodesformen Apoptose und Nekrose bei den genannten drei Zelllinien in unterschiedlichen Temperaturbereichen weiter analysiert. 1.2. Methoden Fibroblasten wurden einer einstĂŒndigen Hyperthermie bei 41,5°C sowie einer Bestrahlung von 2Gy einzeln oder kombiniert ausgesetzt und nach 48 Stunden, einer und zwei Wochen gemessen. Dabei wurde Immunostaining von aktivierten Faktoren der DNA-Schadenserkennung ÎłH2AX, p53BP1, pNBS343 sowie von PML und PCNA durchgefĂŒhrt. Zudem wurden durchflusszytometrisch die zellulĂ€ren Auswirkungen wie Zellzyklusarrest, Seneszenz, Apoptose oder Nekrose mit den Farbstoffen C12FDG, Ann V, 7-AAD, HO342 und PY untersucht. In weiteren Versuchen wurden Fibroblasten, Lymphozyten und lymphoblastoide Zellen ebenfalls durchflusszytometrisch bei unterschiedlichen Temperaturen im Bereich von 37 – 47°C mit den oben genannten Markern analysiert. Dabei hatten die Zellen 48 Stunden Zeit sich vom ausgesetzten thermischen Stress zu erholen, bevor sie gemessen wurde. 1.3. Ergebnisse und Beobachtungen Die Untersuchungen ergaben ĂŒbereinstimmend mit der gegenwĂ€rtigen Literatur, dass bei Fibroblasten Hyperthermie signifikant weniger DNA-SchĂ€den produziert als eine Bestrahlung mit 2Gy. Ein strahlensensibilisierender Effekt nach Vorbehandlung mit Hyperthermie konnte tendenziell gezeigt werden. Eine Signifikanz konnte aber nicht belegt werden. Fibroblasten wurden bei großen thermisch produzierten ZellschĂ€den bevorzugt seneszent, teils auch nekrotisch, wenn auch eine relative Resistenz im Vergleich zu Lymphozyten oder sogar lymphoblastoiden Zellen festzustellen war. Ab Temperaturen ĂŒber 39 / 40°C reagierten diese beiden Zelllinien sehr sensibel gegenĂŒber Hitze. Dies wurde am stark sigmoidal ansteigenden Verlauf der Nekrose bei Lymphozyten und lymphoblastoiden Zellen sichtbar, worauf knapp ein Viertel der Lymphozyten und fast 100% der lymphoblastoiden Zellen bei einer Temperatur von 47°C nekrotisch wurden. Apoptose spielte im Vergleich dazu nur eine relevante Rolle bei moderaten Temperaturen um die 39°C, zeigte sich aber bei hohen Temperaturen rĂŒcklĂ€ufig. 1.4. Praktische Schlussfolgerungen Ein thermischer Additionseffekt ist folglich bei Fibroblasten in Tendenzen erkennbar. Signifikante Ergebnisse wĂ€ren bei Verwendung von höheren Temperaturen denkbar. Als Resultat eines hoch toxischen thermischen Stresses reagiert diese Zelllinie bevorzugt mit Seneszenz, erweist sich aber im Vergleich als relativ resistent, sodass dies in der Betrachtung der Nebenwirkungen einer Hyperthermie-Behandlung von Tumorzellen eine untergeordnete Rolle spielen dĂŒrfte. Nach entsprechender Verifizierung sollten aufgrund der ausgeprĂ€gten Nekrose ab Temperaturen von 40 / 41°C unter den Lymphozyten und lymphoblastoiden Zellen weitere Untersuchungen angestrebt werden. Hierbei gilt es u. a. zu ĂŒberprĂŒfen, ob und wie eine Reduktion der Empfindlichkeit bei diesen Zelllinien gegenĂŒber thermischen Stress erreicht werden kann, Stichwort Thermotoleranzinduktion, sodass eine Lymphozyten-supprimierende Nebenwirkung unter UmstĂ€nden verringert werden kann.2.1. Background and aims Since the 18th century the use and the effects of heat in the treatment of tumor diseases is known. At that time the effects were based on the induction of fever. The exact mechanism of hyperthermia isn’t completely known yet because of a lot of different points of application. Denaturation of proteins and radiosensitization are common proved effects which among others are going to be verified in this paper work. The consequences of thermal damage are especially explored by tumor cells, sparely is known of healthy cell lines like fibroblasts, lymphocytes or lymphoblastoid cells. In this dissertation we analyzed these cell lines at different temperatures for senescence, apoptosis or necrosis. 2.2. Methods Fibroblasts were treated by one hour of hyperthermia at 41.5 degrees C and radiation by 2Gy alone or in combination. The cells were measured at 48 hours, one or two weeks. Immunostaining of activated factors of the DNA damage recognition system like ÎłH2AX, p53BP1, pNBS343 as well as PML and PCNA was realized. Furthermore the cellular consequences like cell cycle arrest, senescence, apoptosis or necrosis were tested with the fluorescence marker C12FDG, Ann V, 7-AAD, HO342 and PY. Afterwards fibroblasts, lymphocytes or lymphoblastoid cells were analyzed between 37 to 47 degrees C with the named markers. The cells had 48 hours to regenerate of the thermal stress before they were measured. 2.3. Results and observations The tests showed according to the present literature that hyperthermia causes significant less DNA damage than radiation of 2Gy by fibroblasts. Radiosensitization of hyperthermia couldn’t be proved significantly, but a tendency was recognized. Fibroblasts stressed by heat preferred above all senescence and less necrosis. It existed a relative resistance to hyperthermia by fibroblasts compared to lymphocytes or lymphoblastoid cells. At temperatures over 39 / 40 degrees C both cell lines reacted very sensible to heat. This showed the sigmoidal increasing curve of necrosis with the temperature by lymphocytes and lymphoblastoid cells. A quarter of lymphocytes and almost 100% of lymphoblastoid cells were necrotic at 47 degrees C. Apoptosis had a relevant part at moderate temperatures about 39 degrees centigrade but decreased at high temperatures. 2.4. Conclusion The thermal addition effects tended to be proved at fibroblasts. Significant results could be possibly reached by higher temperatures to fibroblasts react on high cell toxic thermal stress with senescence. In comparison to lymphocytes or lymphoblastoid cells this cell line is however very resistant to hyperthermia. Consequently these results could be negligibly considered by concerning to the side effects of the treatment of hyperthermia on tumor cells. After verification of our results on lymphocytes or lymphoblastoid cells additional tests are necessary to examine possibilities to reduce the sensitivity of thermal stress on these cell lines. Induction of thermal tolerance could be one of the opportunities to lower the lymphocytes suppressing side effect

    Hochgenaue Roboter: Roboterungenauigkeiten aufspĂŒren und minimieren

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    Genaue Robotersysteme ermöglichen einen effizienten Robotereinsatz insbesondere bei der Offlineprogrammierung. Das Fraunhofer IPA bietet deshalb Verfahren, mit denen die Genauigkeit auch komplexer Robotersysteme vermessen und verbessert werden kann

    The general distribution pattern and mixing probability of Baltic sprat juvenile populations

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    Transport of Baltic sprat Sprattus sprattus L. larvae spawned on different spawning grounds was investigated by detailed drift model simulations for the years 1979–2002. Modeling approaches with and without diurnal vertical migration were applied. We used recently collected data on spawning location, vertical distribution and the timing of spawning as input to a particle tracking model. Results of this modeling study enabled the identification of potential nursery grounds for sprat originating from different spawning grounds. On average, westerly winds are prevailing over the Baltic Sea. This leads to on average higher abundance of juvenile sprat along the southern and the eastern coast lines of the Baltic. The horizontal distribution of simulated larval or 0-group sprat is consistent with the observed distribution of 0-group sprat obtained from the hydroacoustic field surveys. In addition, this analysis identifies the potential for advective mixing between juveniles originating from different spawning sites or from the same spawning site throughout the spawning season. High spatial overlap was found between Arkona- and Bornholm Basin larvae hatched at the beginning of the spawning season. Mixing probability of sprat juveniles between Arkona- and Gotland Basin as well as between Bornholm- and Gotland Basin were on relatively low levels

    Creation of Silicon Vacancy in Silicon Carbide by Proton Beam Writing toward Quantum Sensing Applications

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    Single photon source (SPS) is a key element for quantum spintronics and quantum photonics. Several color centers, silicon vacancy (Vsi), divacancy (VsiVc), carbon antisite carbon vacancy pair (CsiVc), in silicon carbide (SiC) act as SPSs. In those SPSs, spin (S = 3/2) in Vsi can be manipulated even at room temperature and the intensity of its photoluminescence (PL) changes depending on the spin states. Since PL from Vsi is in the near infrared region (around 900 nm), it is expected that Vsi is applied to quantum sensor especially for biological or medical applications. Therefore, quantum sensing based on Vsi in SiC is discussed. In addition, energetic particle irradiation, especially proton beam writing (PBW), is introduced as a method to create Vsi in SiC
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