TY - CHAP A1 - Schmitz, Barbara ED - Kreuzer, Siegfried ED - Meiser, Martin ED - Sigismund, Marcus T1 - "...using different names, as Zeus and Dis" (Arist 16). Concepts of "God" in the letter of Aristeas T2 - Die Septuaginta - Orte und Intentionen N2 - The “Letter of Aristeas” recounts the translations of the Hebrew Bible into Greek. Probably originating in the 2nd century BCE1, the book tells a legend of how the translation of the Torah into Greek came into being. This shows that translating a holy, canonical text or the first time needed explication. Notably, the translation of the godly nomos (Arist 3) comparatively takes up little space (Arist 301–307). And it has to be noted, that “God” is seldom a topic in the Book of Aristeas. The word (ὁ) θεός “God” is found in only three contexts: in the dialogue between king Ptolemaios and Aristeas (Arist 15–21), in the dialogue of the high priest Eleazar and Aristeas (Arist 121–171; above all 128; 130–141; 155–166; 168) and in the question-and-answer-speech during the symposium at the Ptolemaic royal court between the king and the Jewish scholars (Arist 184–294). In analysing the different statements regarding God, the frame of the narrative is of decisive importance: In the Book of Aristeas, “Aristeas” (Ἀριστέας), who writes in Greek, presents himself as the author, but he is also part of the story. Accordingly, Aristeas is the narrator, who tells the story from his own point of view, and at the same time, he is a character in the ‘world’ of the text. This Aristeas presents himself as a Greek and a Non-Jew (Arist 16; 121–171), who already wrote a book (Arist 6) and plans further publications (Arist 322). In the double-role as narrator of the text and protagonist in the text, Aristeas has to be differentiated from the (real) writer/author of the Book of Aristeas, who possibly was Jewish. That means that the (real, probably Jewish) author of the Book of Aristeas presents (or invents) “Aristeas” and gives him the role of the narrator of his text.3 The author portrays Aristeas as a Greek, non-Jewish character, who is a servant of the royal court. This differentiation between narrator and writer/author is of crucial importance for the question of the different conceptions of God in the Book of Aristeas. KW - Aristeas-Brief KW - Gott KW - Aristeas 〈Epistolographus, ca. v3. Jh.〉 Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137671 SP - 703 EP - 716 PB - Mohr Siebeck CY - Tübingen ER - TY - THES A1 - Hautmann, Christoph T1 - "And men whose heads do grow beneath their shoulders" - Encountering the Other in the Illustrations of Shakespeare's "The Tempest" and "Othello" in the Eighteenth and Nineteenth Centuries N2 - Adducing a number of illustrations of Shakespeare's "The Tempest" and "Othello", the purpose of this study is to analyze the transformative processes that took place in the 18th and 18th centuries in Great Britain, regarding the cultural, political and social aspects of its encounters with the other. In this context, especially the depiction of the characters Caliban and Othello are taken into consideration. N2 - Es ist Ziel dieser Arbeit, anhand von einigen ausgewählten Illustrationen von Wiliam Shakespeares "Der Sturm" und "Othello" jenen Wandel zu untersuchen, der sich in Großbritannien im 18. und 19. Jahrhundert hinsichtlich seiner kulturellen, politischen und sozialen Auseinandersetzung mit Andersartigkeit vollzog. Insbesondere die bildliche Darstellung der Figuren des Caliban und des Othello, aber auch ihr Verhältnis zu anderen Personen und Bildelementen bilden in diesem Zusammenhang den Ausgangspunkt der Analyse von solchen sozialen Mechanismen auf mikro- und makrosoziologischer Ebene innerhalb der englischen Gesellschaft des 18. und 19. Jahrhunderts, die durch die Begegnung mit dem Anderen ausgelöst wurden. Die analytische Grundlage bildet dabei der im Grunde literaturtheoretische Ansatz des cultural materialism. Unter Heranziehung neuerer Erkenntnisse der Geschichtswissenschaft jedoch wird die Gleichwertigkeit bildlicher und schriftlicher Dokumente für jede kulturwissenschaftliche Analyse betont. Im Kern dieser theoretischen Herangehensweise steht somit die Annahme, dass jedwede Form kulturellen Schaffens, etwa der darstellenden Künste, sich von historischen, politischen, ökonomischen und sozialen Aspekten, die dieses Schaffen begleiten und bestimmen, nicht nur schwerlich trennen lässt, sondern diesen kontingenten Aspekten eingeschrieben ist. Mit anderen Worten übersteigt der zugrunde gelegte Ansatz auch ein hierarchisierendes Vorgehen, das kulturelles Schaffen gewissermaßen „vor dem Hintergrund“ bestimmter sozialer, kultureller und politischer Entwicklungen betrachtet. KW - Shakespeare KW - William KW - Illustration KW - Das Andere KW - Großbritannien KW - Shakespeare-Illustration KW - Shakespeare illustration Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-45383 ER - TY - THES A1 - Wagh, Dhananjay Anil T1 - "Bruchpilot" -molecular and functional characterization of a novel active zone protein at the Drosophila synapse T1 - "Bruchpilot" - Molekulare und funktionelle Charakterisierung eines neuen Proteins der aktiven Zone der Drosophila-Synapse N2 - Chemical neurotransmission is a complex process of central importance for nervous system function. It is thought to be mediated by the orchestration of hundreds of proteins for its successful execution. Several synaptic proteins have been shown to be relevant for neurotransmission and many of them are highly conserved during evolution- suggesting a universal mechanism for neurotransmission. This process has checkpoints at various places like, neurotransmitter uptake into the vesicles, relocation of the vesicles to the vicinity of calcium channels in order to facilitate Ca2+ induced release thereby modulating the fusion probability, formation of a fusion pore to release the neurotransmitter and finally reuptake of the vesicles by endocytosis. Each of these checkpoints has now become a special area of study and maintains its own importance for the understanding of the overall process. Ca2+ induced release occurs at specialized membrane structures at the synapse known as the active zones. These are highly ordered electron dense grids and are composed of several proteins which assist the synaptic vesicles in relocating in the vicinity of Ca2+ channels thereby increasing their fusion probability and then bringing about the vesicular fusion itself. All the protein modules needed for these processes are thought to be held in tight arrays at the active zones, and the functions of a few have been characterized so far at the vertebrate active zones. Our group is primarily interested in characterizing the molecular architecture of the Drosophila synapse. Due to its powerful genetics and well-established behavioural assays Drosophila is an excellent system to investigate neuronal functioning. Monoclonal antibodies (MABs) from a hybridoma library against Drosophila brain are routinely used to detect novel proteins in the brain in a reverse genetic approach. Upon identification of the protein its encoding genetic locus is characterized and a detailed investigation of its function is initiated. This approach has been particularly useful to detect synaptic proteins, which may go undetected in a forward genetic approach due to lack of an observable phenotype. Proteins like CSP, Synapsin and Sap47 have been identified and characterized using this approach so far. MAB nc82 has been one of the shortlisted antibodies from the same library and is widely used as a general neuropil marker due to the relative transparency of immunohistochemical whole mount staining obtained with this antibody. A careful observation of double stainings at the larval neuromuscular junctions with MAB nc82 and other pre and post-synaptic markers strongly suggested an active zone localization of the nc82 antigen. Synaptic architecture is well characterized in Drosophila at the ultrastructural level. However, molecular details for many synaptic components and especially for the active zone are almost entirely unknown. A possible localization at the active zone for the nc82 antigen served as the motivation to initiate its biochemical characterization and the identification of the encoding gene. In the present thesis it is shown by 2-D gel analysis and mass spectrometry that the nc82 antigen is a novel active zone protein encoded by a complex genetic locus on chromosome 2R. By RT-PCR exons from three open reading frames previously annotated as separate genes are demonstrated to give rise to a transcript of at least 5.5 kb. Northern blots produce a prominent signal of 11 kb and a weak signal of 2 kb. The protein encoded by the 5.5 kb transcript is highly conserved amongst insects and has at its N-terminus significant homology to the previously described vertebrate active zone protein ELKS/ERC/CAST. Bioinformatic analysis predicts coiled-coil domains spread all over the sequence and strongly suggest a function involved in organizing or maintaining the structure of the active zone. The large C-terminal region is highly conserved amongst the insects but has no clear homologues in veretebrates. For a functional analysis of this protein transgenic flies expressing RNAi constructs under the control of the Gal4 regulated enhancer UAS were kindly provided by the collaborating group of S.Sigrist (Gِttingen). A strong pan-neuronal knockdown of the nc82 antigen by transgenic RNAi expression leads to embryonic lethality. A relatively weaker RNAi expression results in behavioural deficits in adult flies including unstable flight and impaired walking behavior. Due to this peculiar phenotype as observed in the first knockdown studies the gene was named “bruchpilot” (brp) encoding the protein “Bruchpilot (BRP)” (German for crash pilot). A pan-neuronal as well as retina specific downregulation of this protein results in loss of ON and OFF transients in ERG recordings indicating dysfunctional synapses. Retina specific downregulation also shows severely impaired optomotor behaviour. Finally, at an ultrastructural level BRP downregulation seems to impair the formation of the characteristic T-shaped synaptic ribbons at the active zones without significantly altering the overall synaptic architecture (in collaboration with E.Asan). Vertebrate active zone protein Bassoon is known to be involved in attaching the synaptic ribbons to the active zones as an adapter between active zone proteins RIBEYE and ERC/CAST. A mutation in Bassoon results in a floating synaptic ribbon phenotype. No protein homologous to Bassoon has been observed in Drosophila. BRP downregulation also results in absence of attached synaptic ribbons at the active zones. This invites the speculation of an adapter like function for BRP in Drosophila. However, while Bassoon mutant mice are viable, BRP deficit in addition to the structural phenotype also results in severe behavioural and physiological anomalies and even stronger downregulation causes embryonic lethality. This therefore suggests an additional and even more important role for BRP in development and normal functioning of synapses in Drosophila and also in other insects. However, how BRP regulates synaptic transmission and which other proteins are involved in this BRP dependant pathway remains to be investigated. Such studies certainly will attract prominent attention in the future. N2 - Die chemische Signalübertragung an Synapsen ist ein komplexer Prozess mit zentraler Bedeutung für die Funktion von Nervensystemen. Man nimmt an, dass er auf einem Zusammenspiel hunderter verschiedener Proteine beruht. Diverse Synopsenproteine haben sich für die Neurotransmission als relevant erwiesen und viele davon sind in der Evolution hoch konserviert, was einen universalen Mechanismus der Neurotransmission wahrscheinlich macht. Dieser Prozess ist in zahlreiche aufeinander folgende Schritte unterteilt, wie die Neurotransmitteraufnahme in Vesikel, den Transport von Vesikeln in die Nنhe von Calciumkanنlen, die Ausbildung einer Fusionspore zur Transmitterausschüttung und schlieكlich die Wiederaufnahme von Vesikeln durch Endozytose. Jeder dieser Teilschritte wird momentan gezielt erforscht und spielt für sich genommen eine zentrale Rolle für das Verstنndnis des gesamten Prozesses. Die Calcium-induzierte Transmitterausschüttung findet an spezialisierten Membranstrukturen der Synapsen statt, den aktiven Zonen. Diese sind hoch organisierte, elektronendichte Gitterstrukturen und bestehen aus verschiedenen Proteinen, die den synaptischen Vesikeln bei der Verlagerung in die Nنhe von Calciumkanنlen behilflich sind. Alle Proteinmodule, die für diese Prozesse nِtig sind, scheinen eng aneinandergereiht an den aktiven Zonen vorzuliegen. Nur von wenigen konnte bisher bei Vertebraten die Funktion an der aktiven Zone charakterisiert werden. Ein Fokus der Arbeitsgruppe, an der diese Doktorarbeit durchgeführt wurde, besteht in der Charakterisierung des molekularen Aufbaus der Synapse von Drosophila. Die Taufliege ist aufgrund eines reichen Angebots hِchsteffektiver genetischer Methoden und vielfنltiger Verhaltensparadigmen ein exzellentes Modellsystem, um die neuronale Signalübertragung zu untersuchen. Monoklonale Antikِrper (MAKs) aus einer Hybridomabank gegen das Drosophila Gehirn werden standardmنكig verwendet, um neue Gehirnproteine mittels der „reverse genetics“- Methode zu identifizieren. Dazu wird der entsprechende genetische Lokus charakterisiert und eine detaillierte Untersuchung der Proteinfunktion initiiert. Diese Vorgehensweise war besonders hilfreich bei der Identifizierung von Synapsenproteinen, die bei der „forward genetics“-Methode aufgrund des Fehlens eines beobachtbaren Phنnotyps übersehen würden. Proteine wie CSP, Synapsin und Sap47 wurden so gefunden und charakterisiert. I MAK nc82 stammt aus dieser Hybridomabank und wird in vielen Labors als allgemeiner Neuropilmarker aufgrund seiner hervorragenden Fنrbungseigenschaften in Gehirnprنparaten verwendet. Doppelfنrbungen der larvalen neuromuskulنren Synapse mit dem Antikِrper nc82 in Kombination mit anderen prن- und postsynaptischen Markern deuteten stark auf eine Lokalisierung des Antigens an der aktiven Zone hin. Die Synapsenarchitektur von Drosophila ist auf der ultrastrukturellen Ebene gut verstanden. Jedoch sind die molekularen Details vieler Synapsenkomponenten, besonders die der aktiven Zone, nicht bekannt. Die vermutete Lokalisierung des nc82 Antigens an der aktiven Zone war daher der Ansatzpunkt, eine biochemische Charakterisierung zu initiieren und das entsprechende Gen zu identifizieren. In der vorliegenden Arbeit wird durch 2-D Gelelektrophorese und Massenspektrometrie gezeigt, das das nc82 Antigen ein neues Protein der aktiven Zone ist, welches von einem komplexen Genlokus auf Chromosom 2R kodiert wird. Durch RT-PCR wurde gezeigt, dass die Exons von drei offenen Leserastern, die bisher als getrennte Gene annotiert wurden, ein Transkript von mindestens 5,5 kb Lنnge kodieren. Northern Blots ergaben ein deutliches Signal bei 11 kb und ein schwنcheres bei 2 kb. Das von dem 5,5 kb Transkript resultierende Protein ist hoch konserviert in der Gruppe der Insekten und weist an seiner N-terminalen Domنne eine signifikante Homologie zu den bisher beschriebenen Vertebratenproteinen der aktiven Zone ELKS/ERC/CAST auf. Bioinformatische Analysen sagen „coiled-coil“ Domنnen vorher, die über die gesamte Sequenz verteilt sind. Dies deutet stark auf eine Funktion bei der Organisation oder der Aufrechterhaltung der prنsynaptischen Struktur hin. Die groكe C-terminale Region ist zwar bei Insekten hoch konserviert, zeigt aber keine eindeutige Homologie zu Proteinen von Vertebraten. Für die Funktionsanalyse dieses Proteins wurden transgene Fliegen, die UAS-RNAi Konstrukte in ihrem Genom tragen und durch entsprechende GAL4-Linien getrieben werden kِnnen, freundlicherweise von der kollaborierenden Arbeitsgruppe von S. Sigrist (Gِttingen) zur Verfügung gestellt. Der pan-neuronale „knock-down“ des nc82 Antigens durch transgene RNAi-Expression führt zu embryonaler Letalitنt. Eine schwنchere RNAi-Expression führt bei adulten Fliegen zu Verhaltensdefekten, wie instabilem Flug und beeintrنchtigtem Laufverhalten. Aufgrund dieser Phنnotypen, die in den ersten „knock-down“ Studien beobachtet wurden, wurde das Gen „bruchpilot“ (brp) und das zugehِrige Protein „Bruchpilot“ (BRP) genannt. Die pan-neuronale, sowie die retinaspezifische Reduktion des Proteins führt zu einem Verlust der ON und OFF Transienten des Elektroretinogramms, was auf nichtfunktionelle Synapsen hindeutet. Die retinaspezifische Reduktion des Proteins hat eine Beeintrنchtigung der optomotorischen Reaktion zur Folge. Auكerdem scheint auf der ultrastrukturellen Ebene die Bildung der charakteristischen T-fِrmigen „ribbons“ der aktiven Zonen beeintrنchtigt zu sein, jedoch ohne signifikante Verنnderungen der Gesamtarchitektur der Synapse (in Kollaboration mit E. Asan). Von Basson, einem Protein der aktiven Zone bei Vertebraten, ist bekannt, dass es an der Anheftung der synaptischen „ribbons“ an den aktiven Zonen beteiligt ist. Es fungiert als Adapter zwischen RIBEYE und ELKS/ERC/CAST, zwei weiteren Proteinen der aktiven Zone. Die Mutation von Bassoon hat zur Folge, dass die synaptischen „ribbons“ frei im Zytoplasma treiben. Für Bassoon ist kein homologes Drosophila-Protein bekannt. Die Reduktion von BRP bedingt ebenfalls ein Fehlen befestigter „ribbons“ an der aktiven Zone. Dies kِnnte auf eine Art Adapterfunktion von BRP hindeuten. Jedoch hat das Fehlen von BRP zusنtzlich zum strukturellen Phنnotyp auch deutliche Verhaltensabnormalitنten und starke physiologische Beeintrنchtigungen zur Folge. Eine noch stنrkere Reduktion bedingt auكerdem embryonale Lethalitنt, wohingegen Mausmutanten ohne Bassoon lebensfنhig sind. Daraus ergibt sich, dass BRP eine weitere, wichtige Rolle wنhrend der Entwicklung und für die Funktion von Synapsen bei Drosophila und mِglicherweise auch bei anderen Insekten einnimmt. Es muss aber noch geklنrt werden, auf welche Weise BRP die synaptische Signalübertragung reguliert und welche anderen Proteine in diesem BRP-abhنngigen Pfad involviert sind. Derartige Studien werden mit Sicherheit in der Zukunft eine bedeutende Rolle spielen. KW - Taufliege KW - Synapse KW - Proteine KW - Molekulargenetik KW - Bruchpilot KW - Drosophila-Synapse KW - Bruchpilot KW - Drosophila synapse Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-14989 ER - TY - JOUR A1 - Güder, Gülmisal A1 - Brenner, Susanne A1 - Angermann, Christiane E. A1 - Ertl, Georg A1 - Held, Matthias A1 - Sachs, Alfred P. A1 - Lammers, Jan Willem A1 - Zanen, Peter A1 - Hoes, Arno W. A1 - Störk, Stefan A1 - Rutten, Frans H. T1 - "GOLD or lower limit of normal definition? a comparison with expert-based diagnosis of chronic obstructive pulmonary disease in a prospective cohort-study" N2 - Background: The Global initiative for chronic Obstructive Lung Disease (GOLD) defines COPD as a fixed postbronchodilator ratio of forced expiratory volume in 1 second and forced vital capacity (FEV1/FVC) below 0.7. Agedependent cut-off values below the lower fifth percentile (LLN) of this ratio derived from the general population have been proposed as an alternative. We wanted to assess the diagnostic accuracy and prognostic capability of the GOLD and LLN definition when compared to an expert-based diagnosis. Methods: In a prospective cohort study, 405 patients aged ≥ 65 years with a general practitioner’s diagnosis of COPD were recruited and followed up for 4.5 (median; quartiles 3.9; 5.1) years. Prevalence rates of COPD according to GOLD and three LLN definitions and diagnostic performance measurements were calculated. The reference standard was the diagnosis of COPD of an expert panel that used all available diagnostic information, including spirometry and bodyplethysmography. Results: Compared to the expert panel diagnosis, ‘GOLD-COPD’ misclassified 69 (28%) patients, and the three LLNs misclassified 114 (46%), 96 (39%), and 98 (40%) patients, respectively. The GOLD classification led to more false positives, the LLNs to more false negative diagnoses. The main predictors beyond the FEV1/FVC ratio for an expert diagnosis of COPD were the FEV1 % predicted, and the residual volume/total lung capacity ratio (RV/TLC). Adding FEV1 and RV/TLC to GOLD or LLN improved the diagnostic accuracy, resulting in a significant reduction of up to 50% of the number of misdiagnoses. The expert diagnosis of COPD better predicts exacerbations, hospitalizations and mortality than GOLD or LLN. Conclusions: GOLD criteria over-diagnose COPD, while LLN definitions under-diagnose COPD in elderly patients as compared to an expert panel diagnosis. Incorporating FEV1 and RV/TLC into the GOLD-COPD or LLN-based definition brings both definitions closer to expert panel diagnosis of COPD, and to daily clinical practice. KW - Medizin KW - COPD diagnosis KW - lower limit of normal KW - GOLD KW - validation Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75193 ER - TY - JOUR A1 - Meule, Adrian A1 - Beck Teran, Carina A1 - Berker, Jasmin A1 - Gründel, Tilman A1 - Mayerhofer, Martina A1 - Platte, Petra T1 - "On the differentiation between trait and state food craving: Half-year retest-reliability of the Food Cravings Questionnaire-Trait-reduced (FCQ-T-r) and the Food Cravings Questionnaire-State (FCQ-S)" N2 - Background: Food craving refers to an intense desire to consume a specific food. The Food Cravings Questionnaires (FCQs) assess food cravings on a trait and a state level. Method: The current study examined half-year retest-reliability of the Food Cravings Questionnaire-Trait-reduced (FCQ-T-r) and the Food Cravings Questionnaire-State (FCQ-S) and reports associations with current food deprivation in female students. Results: The FCQ-T-r had higher retest-reliability (rtt = .74) than the FCQ-S (rtt = .39). Although trait food craving was correlated with state food craving, it was unaffected by current food deprivation. Conclusions: Although state and trait food craving are interdependent, the FCQs are able to differentiate between the two. As scores of the FCQ-T-r represent a stable trait, but are also sensitive to changes in eating behavior, they may be useful for the investigation of the course of eating disorders and obesity. KW - Food craving KW - Food Cravings Questionnaires KW - Retest-reliability KW - University students Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-110585 ER - TY - JOUR A1 - Buder, Kristina A1 - Lapa, Constantin A1 - Kreissl, Michael C. A1 - Schirbel, Andreas A1 - Herrmann, Ken A1 - Schnack, Alexander A1 - Bröcker, Eva-Bettina A1 - Goebeler, Matthias A1 - Buck, Andreas K. A1 - Becker, Jürgen C. T1 - "Somatostatin receptor expression in Merkel cell carcinoma as target for molecular imaging" N2 - Background Merkel cell carcinoma (MCC) is a rare cutaneous neoplasm with increasing incidence, aggressive behavior and poor prognosis. Somatostatin receptors (SSTR) are expressed in MCC and represent a potential target for both imaging and treatment. Methods To non-invasively assess SSTR expression in MCC using PET and the radiotracers [68Ga]DOTA-D-Phe1-Tyr3-octreotide (DOTATOC) or -octreotate (DOTATATE) as surrogate for tumor burden. In 24 patients with histologically proven MCC SSTR-PET was performed and compared to results of computed tomography (CT). Results SSTR-PET detected primary and metastatic MCC lesions. On a patient-based analysis, sensitivity of SSTR-PET was 73% for nodal metastases, 100% for bone, and 67% for soft-tissue metastases, respectively. Notably, brain metastases were initially detected by SSTR-PET in 2 patients, whereas liver and lung metastases were diagnosed exclusively by CT. SSTR-PET showed concordance to CT results in 20 out of 24 patients. Four patients (17%) were up-staged due to SSTR-PET and patient management was changed in 3 patients (13%). Conclusion SSTR-PET showed high sensitivity for imaging bone, soft tissue and brain metastases, and particularly in combination with CT had a significant impact on clinical stage and patient management. KW - Merkel cell carcinoma KW - Molecular imaging KW - Somatostatin receptor expression KW - Positron emission tomography Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-110326 ER - TY - JOUR A1 - Steinert, Andre F. A1 - Rudert, Maximilian A1 - Sieker, Jakob T. T1 - "Symptomatic loosening of a total knee arthroplasty caused by a tibial chondrosarcoma – a case report" N2 - Premature implant loosening following total knee arthroplasty (TKA) can have several causes. In this article we report on a rare case of a 74 year old male patient suffering tibial component loosening 14 month after primary TKA. The patient did neither have any malignancies nor joint arthroplasty before. Upon clinical examination the range of motion in the diseased knee was painfully restricted to 80° of knee flexion, with the patient increasingly suffering sleeping and resting pain, and also at weight bearing. In standard radiographs, loosening of the TKA due to a large osteolysis at the tibial component was evident. Local computed tomography (CT) of the right knee revealed loosening of the tibial component due to a presumably malign bone tumor. For determination of the final diagnosis a representative biopsy of the tumor was taken by open surgery prior to the tumor resection. Histopathologic evaluation of the biopsy revealed a periprosthetic myxoid chondrosarcoma of the proximal tibia. Pre-operative staging examination included CT scans of lung and abdomen, as well as a bone scintigraphy which revealed no signs of tumor metastasis in the body. Surgical management comprised wide tumor resection and implantation of a hinged tumor knee arthroplasty with replacements of the distal femur and proximal tibia, as well as a patella tendon replacement using a synthetic ligament. Revision surgery was necessary twice due to impaired wound healing and critical soft tissue coverage, and treatment included a gastrocnemius muscle flap with skin mesh graft covering. Unfortunately long-term follow-up examinations could not be obtained, as the patient deceased due to an alveolitis during rehabilitation. In summary, the specifics of this rare case of aseptic TKA loosening, and the unusual circumstances of chondrosarcoma diagnosis and treatment are informative for those providing surgical treatment of similar cases. KW - Total knee arthroplasty KW - Bone tumor KW - Chondrosarcoma KW - Aseptic loosening Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-110341 ER - TY - THES A1 - Mann, Daniel T1 - "The smell of Ujamaa is still there" - Tanzania’s Path of Development between Grassroots Socialism and Central State Control in Ruvuma N2 - In the 1960s, when most African nations gained their independence after the age of colonialism, several theories and strategies emerged with the goal of "developing" these apparently "underdeveloped" territories. One of the most influential approaches for this task was represented in Julius K. Nyerere´s idea of Ujamaa, the Tanzanian version of African socialism. Even before the Arusha Declaration established Ujamaa as a national development strategy in 1967, several groups of politicized young farmers took to the empty countryside of Tanzania to implement their own version of cooperative development. From one of these attempts emerged the Ruvuma Development Association (RDA), which organized up to 18 villages in southwestern Tanzania. The RDA became the inspiration for Nyerere´s concretization of Ujamaa and its implementation on national level. Yet, the central state could not replicate the success of the peasants, which was based on voluntariness and intrinsic motivation. In 2015, this exploratory study has revisited the Region of Ruvuma. Through a case study approach, relying mostly on qualitative methods, new insights into the local history of Ujamaa and its perception have been gathered. In particular, narrative interviews with contemporary witnesses and group interviews with the present-day farmers’ groups have been conducted. Furthermore, NGOs active within the region, as well as regional and local government institutions were among the key stakeholders identified to concretize the local narrative of Ujamaa development. All interviews were analyzed according to the principles of qualitative content analysis. Additionally, individual villager questionnaires were used to achieve a more holistic picture of the local perception of development, challenges and the Ujamaa era. None of the original Ujamaa groups of the times of the RDA was still operational at the time of research and no case of village-wide organization of collective agriculture could be observed. Nevertheless, in all of the three case study villages, several farmers’ groups (vikundi) were active in organizing development activities for their members. Furthermore, the perception of the Ujamaa era was generally positive throughout all of the case study sites. Yet, there have been significant differences in this perception, based on the village, age, gender and field size of the recipients. Overall, the period of Ujamaa was seen as an inspiration for present-day group activities, and the idea of such activities as a remedy for the developmental challenges of these villages was common among all stakeholders. This thesis concludes that the positive perception of group activities as a vehicle for village development and the perception of Ujamaa history as a positive asset for the inception and organization of farmers’ groups would be highly beneficial to further attempts to support such development activities. However, the limitations in market access and capital availability for these highly-motivated group members have to be addressed by public and private development institutions. Otherwise, "the smell of Ujamaa" will be of little use for the progress of these villages. N2 - In den 1960er Jahren, als die meisten Nationen Afrikas ihre Unabhängigkeit erlangten, entstanden etliche Strategien und Theorien, welche die "Entwicklung" dieser „unterentwickelten“ Territorien zum Ziel hatten. Einer der einflussreichsten Ansätze für dieses Ziel war Julius K. Nyereres Idee von Ujamaa, der tansanischen Variante des afrikanischen Sozialismus. Noch bevor die Arusha Deklaration Ujamaa 1967 als nationale Entwicklungsstrategie verankerte, versuchten sich verschiedene Gruppen junger, politisierter Bauern an ihrer eigenen Version der kooperativen Entwicklung im dünn besiedelten ländlichen Raum Tansanias. Aus einem dieser Versuche ging die Ruvuma Development Association (RDA) hervor, welche bis zu 18 Dörfer im Südwesten des Landes organisierte. Die RDA wurde die Inspiration für Nyereres Konkretisierung von Ujamaa, sowie dessen Umsetzung auf nationaler Ebene. Allerdings war der Zentralstaat nicht in der Lage, den auf Freiwilligkeit und intrinsischer Motivation beruhenden Erfolg dieser einfachen Bauern zu reproduzieren. Die vorliegende explorative Studie wurde 2015 in der Region Ruvuma durchgeführt und konnte durch einen, im wesentlich auf qualitativen Methoden beruhenden, Case-Study Ansatz neue Einblicke in die lokale Ujamaa-Geschichte sowie deren Wahrnehmung sammeln. Insbesondere wurden narrative Zeitzeugeninterviews und Gruppeninterviews mit heutigen Bauerngruppen durchgeführt. Zur Konkretisierung des lokalen Narratives der Ujamaa Entwicklung wurden zudem in der Region aktive NGOs sowie Regional- und Kommunalverwaltung befragt. Alle Interviews wurden mittels qualitativer Inhaltsanalyse ausgewertet. Zusätzlich dienten, an individuelle Dorfbewohner gerichtete, Fragebögen zur Herausarbeitung eines umfassenden Bildes der lokalen Wahrnehmung von Entwicklung, Herausforderungen und der Ujamaa Ära an sich. Keine der ursprünglichen Ujamaa Gruppen war zum Zeitpunkt der Erhebung noch aktiv. Ebenso konnte kein Fall einer das ganze Dorf umfassenden kollektiven Landwirtschaft beobachtet werden – kleinere Bauerngruppen (vikundi) kristallisierten sich dagegen als rezente Form kooperativer Entwicklungsmodelle heraus. Darüber hinaus war die Wahrnehmung der Ujamaa Ära in allen untersuchten Dörfern überwiegend positiv. Jedoch zeigten sich signifikante Unterschiede dieser Wahrnehmung bezüglich des Wohnortes, des Alters, des Geschlechts und der Größe des Feldes der Befragten. Insgesamt wurde die Zeit von Ujamaa als eine Inspiration für heutige gruppenbasierte Entwicklungsaktivitäten gesehen, welche wiederum von allen Akteuren als Möglichkeit zur Überwindung der Entwicklungsprobleme dieser Dörfer gesehen wurden. Diese Dissertation kommt zu dem Schluss, dass die positive Wahrnehmung von Gruppenaktivitäten als ein Instrument zur kommunalen Entwicklung und die Wahrnehmung der Ujamaa Ära als ein positives "Asset" für die Gründung und Organisation von vikundi sehr vorteilhafte Voraussetzungen für weitere Entwicklungsaktivitäten bieten. Allerdings fehlen diesen Gruppen Kapital und Marktzugang. Dies muss von staatlichen wie nichtstaatlichen Entwicklungsorganisationen angegangen werden, andernfalls wird der "smell of Ujamaa" wenig zum Fortschritt in diesen Dörfern beitragen. T3 - Würzburger Geographische Arbeiten - 121 KW - Ujamaa-Sozialismus KW - Tansania KW - Ruvuma Development Association KW - Entwicklungstheorie KW - Cooperative Development KW - Rural Development Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-154079 SN - 978-3-95826-066-5 (print) SN - 978-3-95826-067-2 (online) SN - 0510-9833 SN - 2194-3656 N1 - Parallel erschienen als Druckausgabe in Würzburg University Press, 978-3-95826-066-5, 31,80 EUR. PB - Würzburg University Press CY - Würzburg ET - 1. Auflage ER - TY - JOUR A1 - Kestler, Thomas A1 - Lucca, Juan Bautista A1 - Krause, Silvana T1 - 'Break-In Parties' and Changing Patterns of Democracy in Latin America JF - Brazilian Political Science Review N2 - Although Lijphart's typology of consensus and majoritarian democracy can be regarded as the most widely used tool to classify democratic regimes, it has been rarely applied to Latin America so far. We try to fill this gap by adapting Lijphart's typological framework to the Latin American context in the following way. In contrast to previous studies, we treat the type of democracy as an independent variable and include informal factors such as clientelism or informal employment in our assessment of democratic patterns. On this basis, we aim to answer the following questions. First, how did the patterns of democracy evolve in Latin America over the two decades between 1990 and 2010 and what kind of differences can be observed in the region? Second, what are the institutional determinants of the observed changes? We focus on the emergence of new parties because of their strong impact on the first dimension of Lijphart's typology. From our observations we draw the following tentative conclusions: If strong new parties established themselves in the party system but failed to gain the presidency, they pushed the system towards consensualism. Conversely, new parties that gained the presidency produced more majoritarian traits. KW - break-in parties KW - types of government KW - Latin America KW - democracy KW - informality Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171333 VL - 10 IS - 1 ER - TY - JOUR A1 - Andres, Katharina T1 - 'Fashion's Final Frontier': The Correlation of Gender Roles and Fashion in Star Trek JF - Culture Unbound N2 - Since its creation in 1966, Star Trek has been a dominant part of popular culture and as thus served as the source for many cultural references. Star Trek’s creator Gene Roddenberry wanted to realize his vision of a utopia but at the same time, he used the futuristic setting of the show to comment on the present time, on actual social and political circumstances. This means that each series can be regarded as a mirror image of the time in which it was created. The clothing of the characters in the different series is one part of that image. The uniforms of The Original Se-ries show influences of the 1960s pop art movement as well as the mini-skirt trend that experienced its peak in that decade. In the course of almost 40 years, howev-er, many things changed. In the 1990s, in Deep Space Nine and Voyager, a unisex uniform replaced the mini-dresses, with few exceptions; the colorful shirts gave way to ones that were mostly black. This trend continues into the new century. This essay interprets the evolution of the female officers’ uniforms from femi-nized dresses to androgynous clothing over the development of the series as a reflection of the change of gender roles in contemporary American society. The general functions of the female characters’ uniforms are the central object of its analysis while the few, but noteworthy exceptions to this pattern are given specif-ic attention. Finally, one of the most intriguing lines of enquiry is, how the pre-quel series Enterprise, supposed to be set before The Original Series, but pro-duced and aired from 2001 to 2005, fits in the picture. KW - Star Trek KW - science fiction KW - fashion KW - women KW - 1960s KW - backlash Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128827 VL - 5 ER - TY - THES A1 - Gohli, Hannes T1 - 'Protect the Environment, Build the Homeland' - A Study of the Sino-Singapore Tianjin Eco City's Measures for Citizens to Act in an Environmentally Sustainable Fashion T1 - 'Beschützt die Umwelt, Baut das Vaterland': Eine Studie zu Bürgerinitiativen der Sino-Singapore Tianjin Eco City zur Förderung einer nachhaltigen Konsumgesellschaft N2 - In order to achieve objectives of sustainable development, the Sino-Singapore Tianjin Eco City has devised a set of Key Performance Indicators, which require the collaboration of regional government and industrial entities, but also residents to be accomplished. Through qualitative interviews with eco citizens, this study offers an insight into life in an eco city and how aware residents are of their new home’s targets and incentives. The thesis investigates, how the eco city encourages residents, who have often never received adequate environmental education, to recycle and adapt their purchasing behaviour. The findings reveal the existence of several technical measures, practical incentive schemes and dissemination techniques that encourage residents to act according to environmental considerations. However, residents are often unaware of the numerical targets or do not make the connection between incentive and intended behaviour. The study highlights possibilities for improvement, in order to enhance residents’ understanding of the eco city’s objectives. After all, without resident participation and understanding, the Key Performance Indicators may be unattainable and the eco city’s eventual economic, social and environmental success in jeopardy. N2 - Die vorliegende Arbeit untersucht, basierend auf acht qualitativ-ausgewerteten Interviews die Motivation der Bürger einer Chinesischen Eco City in diese neuartige, auf Nachhaltigkeit hinzielende Siedlung zu ziehen und ob nach dem Umzug eine spürbare Veränderung im Konsumverhalten auf Grund der örtlichen Anreizsysteme zu verspüren war. Die Resultate zeigen, dass trotz technisch ausgeklügelter und in China einzigartigen Maßnahmen in der Wiederverwertung, Elektrizitätsgewinnung und Konsumsteuerung, die Bürger noch zu wenig in die Ziele der Eco City mit eingebunden werden und deshalb oft über potentielle Vorteile einer umweltfreundlichen Lebensweise in der Stadt nicht informiert sind. KW - Green Consumer Behaviour KW - Eco Cities KW - Qualitative Research KW - China Studies KW - Sino-Singapore Tianjin Eco City KW - Key Performance Indicators KW - Green Purchasing Behaviour KW - Incentives KW - Qualitative Study Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-206607 ER - TY - CHAP A1 - Middelhoff, Frederike T1 - (Not) Speaking for Animals and the Environment: Zoopoetics and Ecopoetics in Yoko Tawada’s Memoirs of a Polar Bear T2 - Texts, Animals, Environments: Zoopoetics and Ecopoetics N2 - No abstract available. KW - Animal Studies KW - Cultural Animal Studies KW - Cultural Studies KW - Ecocriticism KW - Environmental Humanities KW - Human-Animal Studies KW - Literary Studies Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-178142 UR - https://www.rombach-verlag.de/buecher/suchergebnis/rombach/buch/details/texts-animals-environments.html PB - Rombach Druck- und Verlagshaus CY - Freiburg i. Br. ER - TY - JOUR A1 - Bringmann, Gerhard A1 - Ortmann, Thomas A1 - Zagst, Rainer A1 - Schoener, Bernd A1 - Assi, Laurent Ake A1 - Burschka, Christian T1 - +/- Dioncophyllacine A, a naphthylisoquinoline alkaloid with a 4-methoxy substituent from the leaves of Triphyophyllum peltatum N2 - The isolation and structure elucidation of rac-dioncophyllacine A from the leaves of Triphyophyllun peltatum, is described. Unlike all other naphthylisoquinoline alkaloids, this fully dehydrogenated representative has an additional methoxy group at C-4, the position of which is deduced from NOE results. Dioncophyllacine A has a 7,1' site of the biaryl axis, as in dioncophylline A. Its constitution is confirmed by an X-ray structure analysis, which shows that the crystalline form of this new alkaloid is racemic. KW - Dioncophyllaceae KW - Triphyophyllum peltaturn KW - Dioncophyllaceae leaves KW - (± )-dioncophyllacine A KW - naphthylisoquinoline alkaloids KW - structure elucidation Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31873 ER - TY - JOUR A1 - Christl, Manfred A1 - Schreck, Michael T1 - 1,2,3,5,8,8a-Hexahydronaphthalin aus 1,2-Cyclohexadien N2 - Reaktionen von 1,3-Butadien und einigen seiner Methylderivate mit 1a und 1- Methyl-1,2-cyclohexadien 1b sowie den Übergang der [2 + 2]-Cycloaddukte 2 und 3 in das bisher unbekannte 1,2,3,5,8,8a-HexahydronaphthaJin 4a und einige seiner Methylderivate KW - Chemie KW - Butadien Y1 - 1987 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31656 ER - TY - JOUR A1 - Christl, Manfred A1 - Braun, Martin A1 - Müller, Germar T1 - 1,2,4-Cyclohexatriene, an Isobenzene, and Bicyclo[4.4.0)deca-1,3,5,7,8-pentaene, an Isonaphthalene: Generation and Trapping Reactions N2 - No abstract available KW - Organische Chemie Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-58639 ER - TY - JOUR A1 - Braunschweig, Holger A1 - Damme, Alexander T1 - 1,2-Bis(dimethylamino)-1,2-bis(2,4,6-triisopropylphenyl)diborane(4) N2 - In the molecular structure of the title compound, C34H58B2N2, each B atom of the diborane(4) is connected to one dimethylamino group and one Tip ligand (Tip = 2,4,6-triisopropylphenyl). These findings indicate that the increased steric demand of the Tip groups exerts influence solely on the B—B separation but not on the overall geometry of the title compound. KW - Anorganische Chemie Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-67639 ER - TY - JOUR A1 - Klotz, Barbara A1 - Mentrup, Birgit A1 - Regensburger, Martina A1 - Zeck, Sabine A1 - Schneidereit, Jutta A1 - Schupp, Nicole A1 - Linden, Christian A1 - Merz, Cornelia A1 - Ebert, Regina A1 - Jakob, Franz T1 - 1,25-Dihydroxyvitamin D3 Treatment Delays Cellular Aging in Human Mesenchymal Stem Cells while Maintaining Their Multipotent Capacity JF - PLoS ONE N2 - 1,25-dihydroxyvitamin D3 (1,25D3) was reported to induce premature organismal aging in fibroblast growth factor-23 (Fgf23) and klotho deficient mice, which is of main interest as 1,25D3 supplementation of its precursor cholecalciferol is used in basic osteoporosis treatment. We wanted to know if 1,25D3 is able to modulate aging processes on a cellular level in human mesenchymal stem cells (hMSC). Effects of 100 nM 1,25D3 on hMSC were analyzed by cell proliferation and apoptosis assay, beta-galactosidase staining, VDR and surface marker immunocytochemistry, RT-PCR of 1,25D3-responsive, quiescence-and replicative senescence-associated genes. 1,25D3 treatment significantly inhibited hMSC proliferation and apoptosis after 72 h and delayed the development of replicative senescence in long-term cultures according to beta-galactosidase staining and P16 expression. Cell morphology changed from a fibroblast like appearance to broad and rounded shapes. Long term treatment did not induce lineage commitment in terms of osteogenic pathways but maintained their clonogenic capacity, their surface marker characteristics (expression of CD73, CD90, CD105) and their multipotency to develop towards the chondrogenic, adipogenic and osteogenic pathways. In conclusion, 1,25D3 delays replicative senescence in primary hMSC while the pro-aging effects seen in mouse models might mainly be due to elevated systemic phosphate levels, which propagate organismal aging. KW - perspectives KW - bone marrow KW - mutant mice KW - oxidative stress KW - transcription factors KW - vitamin-D-receptor KW - differentiation KW - tissue KW - 2',7'-dichlorofluorescin KW - homeostasis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-133392 VL - 7 IS - 1 ER - TY - JOUR A1 - Zapf, Ludwig A1 - Radius, Udo A1 - Finze, Maik T1 - 1,3-bis(tricyanoborane)imidazoline-2-ylidenate anion - a ditopic dianionic N-heterocyclic carbene ligand JF - Angewandte Chemie International Edition N2 - The 1,3-bis(tricyanoborane)imidazolate anion 1 was obtained in high yield from lithium imidazolate and B(CN)\(_3\)−pyridine adduct. Anion 1 is chemically very robust and thus allowed the isolation of the corresponding H\(_5\)O\(_2\)\(^+\) salt. Furthermore, monoanion 1 served as starting species for the novel dianionic N-heterocyclic carbene (NHC), 1,3-bis(tricyanoborane)imidazoline-2-ylidenate anion 3 that acts as ditopic ligand via the carbene center and the cyano groups at boron. First reactions of this new NHC 3 with methyl iodide, elemental selenium, and [Ni(CO)\(_4\)] led to the methylated imidazolate ion 4, the dianionic selenium adduct 5, and the dianionic nickel tricarbonyl complex 6. These NHC derivatives provide a first insight into the electronic and steric properties of the dianionic NHC 3. Especially the combination of properties, such as double negative charge, different coordination sites, large buried volume and good σ-donor and π-acceptor ability, make NHC 3 a unique and promising ligand and building block. KW - inorganic chemistry KW - N-heterocyclic carbene KW - anioniccarbene KW - boron KW - cyanoborate KW - imidazolate Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256498 VL - 60 IS - 33 ER - TY - THES A1 - Rauch, Florian T1 - 1,3-Bis(trifluoromethyl)benzene: A Versatile Building Block for the Synthesis of New Boron-Containing Conjugated Systems T1 - 1,3-Bis(trifluoromethyl)benzol: Ein vielseitiger Baustein für die Synthese neuer borhaltiger konjugierter Systeme N2 - Chapter 1 Thermally activated delayed fluorescence (TADF) materials provide a strategy to improve external quantum efficiencies of organic light emitting diodes (OLEDs). Because of spin-statistics, 25% singlet and 75% triplet excitons are generated in an electronic device. Conventional organic emitters cannot harvest the triplet excitons, due to low spin orbit coupling, and exhibit low external quantum efficiencies. TADF materials have to be designed in such a way, that the energy gap between the lowest singlet and triplet states (ΔES-T) is sufficiently small to allow reverse intersystem crossing (rISC) in organic systems. An established structure property relationship for the generation of TADF materials is the spatial separation of HOMO and LUMO via an orthogonal arrangement of donor and acceptor in donor-π-acceptor (D-π-A) compounds. This is achieved by increasing the steric bulk of the π-bridge. However, this is not always the most efficient method and electronic parameters have to be considered. In a combined experimental and theoretical study, a computational protocol to predict the excited states in D-π-A compounds containing the B(FXyl)2 (FXyl = 2,6-bis(trifluoromethyl)phenyl) acceptor group for the design of new TADF emitters is presented. To this end, the effect of different donor and π-bridge moieties on the energy gaps between local and charge-transfer singlet and triplet states was examined. To prove the computationally aided design concept, the D-π-B(FXyl)2 compounds Cbz-π (1), Cbz-Meπ (2), Phox-Meπ (3), Phox-MeOπ (4), and MeO₃Ph-FMeπ (5) were synthesized and fully characterized. The photophysical properties of these compounds in various solvents, polymeric film and in a frozen matrix were investigated in detail and show excellent agreement with the computationally obtained data (Figure 5.1). A simple structure-property relationship based on the molecular fragment orbitals of the donor and the π-bridge which minimize the relevant singlet-triplet gaps to achieve efficient TADF emitters is presented.   Chapter 2 Three-coordinate boron is widely used as an acceptor in conjugated materials. In recent years the employment of trifluoromethylated aryls was shown to improve the acceptor properties of such boranes. Astonishingly, the use of ortho-trifluoromethylated aryls in boron containing systems also improves the stability of those systems in regard to their inherent reactivity towards nucleophiles. Borafluorenes are stronger acceptors than their non-annulated triarylborane derivatives. In previous studies, the effect of trifluoromethylated aryls as the exo-aryl moieties in borafluorenes, as well as the effect of fluorination on the backbone, were examined. As the latter suffers from a very low stability, systems using trifluoromethyl groups, both on the exo-aryl as well as the borafluorene backbone were designed in order to maximize both the stability as well as the acceptor strength. Three different perfluoroalkylated borafluorenes were prepared and their electronic and photophysical properties were investigated. The systems have four trifluoromethyl moieties on the borafluorene moiety as well as two trifluoromethyl groups at the ortho positions of their exo-aryl moieties. They differ with regard to the para-substituents on their exo-aryl moieties, being a proton (FXylFBf), a trifluoromethyl group (FMesFBf) or a dimethylamino group (p NMe2-FXylFBf), respectively. Furthermore, an acetonitrile adduct of FMesFBf was obtained and characterized. All derivatives exhibit extraordinarily low reduction potentials, comparable to those of perylenediimides. The most electron deficient derivative FMesFBf was also chemically reduced and its radical anion isolated and characterized. Furthermore, the photophysical properties of all compounds were investigated. All compounds exhibit weakly allowed lowest energy absorptions and very long fluorescent lifetimes of ca. 250 ns up to 1.6 μs; however, the underlying mechanisms differ. The donor substituted derivative p-NMe2-FXylFBf exhibits thermally activated delayed fluorescence from a charge transfer (CT) state, while the FMesFBf and FXylFBf borafluorenes exhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition dipole moments, as suggested by DFT and TD-DFT calculations.   Chapter 3 Conjugated dendrimers find wide application in various fields, such as charge transport/storage or emitter materials in organic solar cells or OLEDs. Previous studies on boron containing conjugated dendrimers are scarce and mostly employ a convergent synthesis approach, lacking a simple, generally applicable synthetic access. A new divergent approach was designed and conjugated triarylborane dendrimers were synthesized up to the 2nd generation. The synthetic strategy consists of three steps: 1) functionalization, via iridium catalyzed C–H borylation; 2) activation, via fluorination of the generated boronate ester with K[HF2] or [N(nBu)4][HF2]; and 3) expansion, via reaction of the trifluoroborate salts with aryl Grignard reagents. The concept was also shown to be viable for a convergent approach. All but one of the conjugated borane dendrimers exhibit multiple, distinct and reversible reduction potentials, making them potentially interesting materials for applications in molecular accumulators (Figure 5.7). Based on their photophysical properties, the 1st generation dendrimers exhibit good conjugation over the whole system. The conjugation does not further increase upon expansion to the 2nd generation, but the molar extinction coefficients increase linearly with the number of triarylborane sub-units, suggesting a potential application as photonic antennas.   Chapter 4 A surprisingly high electronically-driven regioselectivity for the iridium-catalyzed C–H borylation using [Ir(COD)OMe]2 (COD = 1,5-cyclooctadiene) as the precatalytic species, bis(pinacolato)diboron (B2pin2) as the boron source and 4,4’-ditertbutyl-2,2’-bipyridin (dtbpy) as the ligand of D-π-A systems with diphenylamino (1) or carbazolyl (2) moieties as the donor, bis(2,6-bis(trifluoromethyl)phenyl)boryl (B(FXyl)2) as the acceptor, and 1,4-phenylene as the π-bridge was observed. Under these conditions, borylation was observed only at the sterically least encumbered para-positions of the acceptor groups. As boronate esters are versatile building blocks for organic synthesis (C–C coupling, functional group transformations), the C–H borylation represents a simple potential method for post-functionalization by which electronic or other properties of D-π-A systems can be fine-tuned for specific applications. The photophysical and electrochemical properties of the borylated (1-(Bpin)2) and unborylated (1) diphenylamino-substituted D-π-A systems were investigated. Interestingly, the borylated derivative exhibits coordination of THF to the boronate ester moieties, influencing the photophysical properties and exemplifying the non-innocence of boronate esters. N2 - Kapitel 1 Materialien mit thermisch aktivierter verzögerter Fluoreszenz (TADF) eröffnen einen Weg zur Verbesserung der externen Quanteneffizienz von organischen Leuchtdioden (OLEDs). Aufgrund der Spin-Statistik werden in einem elektronischen Bauelement 25% Singulett- und 75% Triplett-Exzitonen erzeugt. Konventionelle organische Emitter können Triplett-Exzitonen aufgrund ihrer geringen Spin-Bahnkopplung nicht nutzen und weisen niedrige externe Quanteneffizienzen auf. TADF-Materialien müssen so entworfen werden, dass die Energielücke zwischen dem niedrigsten Singulett- und dem niedrigsten Triplett-Zustand (ΔES T) ausreichend klein ist, um Rück-Interkombination (rISC) in organischen Systemen zu ermöglichen (Schema 5.1). Eine etablierte Struktur-Eigenschafts-Beziehung für die Erzeugung von TADF-Materialien ist die räumliche Trennung von HOMO und LUMO über eine orthogonale Anordnung von Donor und Akzeptor in Donor-π-Akzeptor-Verbindungen (D-π-A). Dies wird durch eine Vergrößerung des sterischen Anspruchs der π-Brücke erreicht. Dies ist jedoch nicht immer die effizienteste Methode und elektronische Parameter müssen berücksichtigt werden. In einer kombinierten experimentellen und theoretischen Studie wird ein Berechnungsprotokoll zur Vorhersage der angeregten Zustände in D-π-A-Verbindungen, die die Akzeptorgruppe B(FXyl)2 (FXyl = 2,6-Bis(trifluoromethyl)phenyl) enthalten, für das Design neuer TADF-Emitter vorgestellt. Zu diesem Zweck wurde die Wirkung verschiedener Donor- und π-Brückeneinheiten auf die Energielücken zwischen lokalen und ladungsübertragenden Singulett- und Triplett-Zuständen untersucht. Um das durch quantenchemische Rechnungen gestützte Designkonzept zu beweisen, wurden die D-π-B(FXyl)2-Verbindungen Cbz-π (1), Cbz-Meπ (2), Phox-Meπ (3), Phox-MeOπ (4) und MeO₃Ph-FMeπ (5) synthetisiert und vollständig charakterisiert. Die photophysikalischen Eigenschaften dieser Verbindungen in verschiedenen Lösungsmitteln, im Polymerfilm und in einer gefrorenen Glas-Matrix wurden im Detail untersucht und zeigen eine ausgezeichnete Übereinstimmung mit den berechneten Daten. Eine einfache Struktur-Eigenschafts-Beziehung wird vorgestellt, die auf den molekularen Fragment-Orbitalen des Donors und der π-Brücke basiert, welche die relevanten Singulett-Triplett-Lücken minimieren, um effiziente TADF-Emitter zu erhalten.   Kaptiel 2 Dreifach koordiniertes Bor ist als Akzeptor in konjugierten Materialien weit verbreitet. In den letzten Jahren hat sich gezeigt, dass der Einsatz trifluoromethylierter Aromaten die Akzeptoreigenschaften solcher Borane verbessert. Erstaunlicherweise verbessert die Verwendung von ortho-trifluormethylierten Aromaten in borhaltigen Systemen auch die Stabilität dieser Systeme hinsichtlich ihrer inhärenten Reaktivität gegenüber Nukleophilen. Borafluorene sind von Natur aus stärkere Akzeptoren als ihre nicht benzannulierten Triarylboran-Derivate. In frühere Studien wurde bereits die Wirkung trifluormethylierter Aryle als exo-Aryl-Einheiten in Borfluororenen sowie die Auswirkung der Fluorierung auf das Rückgrat untersucht. Da letztere unter einer sehr geringen Stabilität leiden, wurden Systeme mit Trifluoromethylgruppen sowohl auf dem exo-Aromaten- als auch auf dem Borafluoren-Gerüst entwickelt, um sowohl die Stabilität als auch die Akzeptorstärke zu maximieren. Es wurden drei verschiedene perfluoralkylierte Borfluorene hergestellt und ihre elektronischen und photophysikalischen Eigenschaften untersucht. Die Systeme haben vier Trifluoromethylgruppen am Borafluoren-Gerüst sowie zwei Trifluoromethylgruppen an den ortho-Positionen ihrer exo-Aromaten. Sie unterscheiden sich in Bezug auf die para-Substituenten an ihren exo-Aromaten, die jeweils ein Proton (FXylFBf), eine Trifluormethylgruppe (FMesFBf) oder eine Dimethylaminogruppe (p NMe2 FXylFBf) sind. Des Weiteren wurde ein Acetonitril Addukt von FMesFBf isoliert und charakterisiert. Alle Derivate weisen außergewöhnlich niedrige Reduktionspotenziale auf, die mit denen von Perylendiimiden vergleichbar sind. Das elektronenärmste Derivat FMesFBf wurde ebenfalls chemisch reduziert und das korrespondierende radikalische Anion isoliert und charakterisiert. Eigenschaften aller Verbindungen untersucht. Alle Verbindungen weisen schwach erlaubte niederenergetischste Absorptionsmaxima, sowie sehr lange Fluoreszenzlebensdauern von ca. 250 ns bis zu 1,6 μs auf; die zugrunde liegenden Mechanismen, unterscheiden sich jedoch. Das donorsubstituierte Derivat p-NMe2-FXylFBf zeigt thermisch aktivierte verzögerte Fluoreszenz aus einem Ladungstransfer-(CT-)Zustand, während die Borafluorene FMesFBf und FXylFBf aufgrund ihrer Symmetrie und niedriger Übergangsdipolmomente nur schwach erlaubte lokal angeregte (LE-)Übergänge aufweisen, wie aus DFT- und TD-DFT-Berechnungen hervorgeht.   Kapitel 3 Konjugierte Dendrimere finden breite Anwendung in verschiedenen Bereichen, wie z.B. als Ladungstransport/-speicher- oder Emittermaterialien in organischen Solarzellen oder OLEDs. Bisherige Studien über borhaltige konjugierte Dendrimere sind rar gesät und verwenden meist einen konvergenten Syntheseansatz, dem ein einfacher, allgemein anwendbarer synthetischer Zugang fehlt. Ein neuer divergenter Ansatz wurde entwickelt und konjugierte Triarylboran-Dendrimere wurden bis einschließlich zur zweiten Generation synthetisiert. Die Synthesestrategie besteht aus drei Schritten: 1) Funktionalisierung durch Iridium-katalysierte C-H-Borylierung; 2) Aktivierung durch Fluorierung des erzeugten Boronatesters mit K[HF2] oder [N(nBu)4][HF2]; und 3) Expansion durch Reaktion der Trifluoroboratsalze mit Aryl-Grignard-Reagenzien. Das Konzept erwies sich auch auf einen konvergenten Ansatz übertragbar. Bis auf eine Ausnahme weisen alle konjugierten Boran-Dendrimere mehrere, isolierte und reversible Reduktionsprozesse auf, was sie zu potenziell interessanten Materialien für die Anwendung in molekularen Akkumulatoren macht. Basierend auf ihren photophysikalischen Eigenschaften zeigen die Dendrimere der 1. Generation eine gute Konjugation über das gesamte System. Bei der Erweiterung der Systeme zur zweiten Generation nimmt die Konjugation nicht weiter zu. Allerdings steigen die molaren Extinktionskoeffizienten linear mit der Anzahl der Triarylboran-Untereinheiten, was auf eine Möglichkeit für die Anwendung als photonische Antennen hindeutet.   Kapitel 4 Es wurde eine überraschend hohe, elektronisch gesteuerte Regioselektivität für die Iridium-katalysierte C-H-Borylierung mit [Ir(COD)OMe]2 (COD = 1,5-Cyclooctadien) als präkatalytische Spezies, Bis(pinacolato)diboran (B2pin2) als Borquelle und 4,4'-Di-tert-butyl-2,2'-bipyridin (dtbpy) als Ligand von D-π-A-Systemen mit Diphenylamin (1) oder Carbazolyl (Cbz-π (1)) als Donoren, Bis(2,6-bis(trifluoromethyl)phenyl)boryl (B(FXyl)2) als Akzeptor und 1,4-Phenylen als π-Brücke beobachtet. Unter diesen Bedingungen wurde die Borylierung nur an den sterisch am wenigsten gehinderten para-Positionen der Akzeptorgruppen beobachtet. Da Boronatester vielseitige Bausteine für die organische Synthese sind (C-C-Kupplung, funktionelle Gruppentransformationen), stellt die C–H-Borylierung eine einfache, potentielle Methode zur Funktionalisierung dar, mit der elektronische oder andere Eigenschaften von D-π-A-Systemen für spezifische Anwendungen fein abgestimmt werden können. Die photophysikalischen und elektrochemischen Eigenschaften der borylierten (1-(Bpin)2) und unborylierten (1) diphenylaminosubstituierten D-π-A-Systeme wurden untersucht. Interessanterweise weist das borylierte Derivat eine Koordination von THF an die Boronatester-Einheiten auf, was die photophysikalischen Eigenschaften beeinflusst und die Nicht-Unschuld der Boronatester veranschaulicht. KW - Triarylborane KW - Cyclovoltammetrie KW - Verzögerte Fluoreszenz KW - Trifluormethylphenylgruppe KW - Fotophysik Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-211478 ER - TY - JOUR A1 - Kanal, Florian A1 - Keiber, Sabine A1 - Eck, Reiner A1 - Brixner, Tobias T1 - 100-kHz shot-to-shot broadband data acquisition for high-repetition-rate pump–probe spectroscopy N2 - Shot-to-shot broadband detection is common in ultrafast pump–probe spectroscopy. Taking advantage of the intensity correlation of subsequent laser pulses improves the signal-to-noise ratio. Finite data readout times of CCD chips in the employed spectrometer and the maximum available speed of mechanical pump-beam choppers typically limit this approach to lasers with repetition rates of a few kHz. For high-repetition (≥ 100 kHz) systems, one typically averages over a larger number of laser shots leading to inferior signal-to-noise ratios or longer measurement times. Here we demonstrate broadband shot-to-shot detection in transient absorption spectroscopy with a 100-kHz femtosecond laser system. This is made possible using a home-built high-speed chopper with external laser synchronization and a fast CCD line camera. Shot-to-shot detection can reduce the data acquisition time by two orders of magnitude compared to few-kHz lasers while keeping the same signal-to-noise ratio. KW - cameras KW - CCD KW - charge-coupled device KW - modulators KW - time-resolved spectroscopy KW - ultrafast spectroscopy KW - ultrafast measurements Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-112853 ER -