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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

Adjustable white-light emission from a photo-structured micro-OLED array

Krotkus, Simonas, Kasemann, Daniel, Lenk, Simone, Leo, Karl, Reineke, Sebastian 10 January 2017 (has links) (PDF)
White organic light-emitting diodes (OLEDs) are promising candidates for future solid-state lighting applications and backplane illumination in large-area displays. One very specific feature of OLEDs, which is currently gaining momentum, is that they can enable tunable white light emission. This feature is conventionally realized either through the vertical stacking of independent OLEDs emitting different colors or in lateral arrangement of OLEDs. The vertical design is optically difficult to optimize and often results in efficiency compromises between the units. In contrast, the lateral concept introduces severe area losses to dark regions between the subunits, which requires a significantly larger overall device area to achieve equal brightness. Here we demonstrate a color-tunable, two-color OLED device realized by side-by-side alignment of yellow and blue p-i-n OLEDs structured down to 20 μm by a simple and up-scalable orthogonal photolithography technique. This layout eliminates the problems of conventional lateral approaches by utilizing all area for light emission. The corresponding emission of the photo-patterned two-unit OLED can be tuned over a wide range from yellow to white to blue colors. The independent control of the different units allows the desired overall spectrum to be set at any given brightness level. Operated as a white light source, the microstructured OLED reaches a luminous efficacy of 13 lm W−1 at 1000 cd m−2 without an additional light outcoupling enhancement and reaches a color rendering index of 68 when operated near the color point E. Finally, we demonstrate an improved device lifetime by means of size variation of the subunits.
342

Do socio-cultural factors influence medical students’ health status and health-promoting behaviors? A cross-sectional multicenter study in Germany and Hungary

Riemenschneider, Henna, Balázs, Péter, Balogh, Erika, Bartels, Axel, Bergmann, Antje, Cseh, Károly, Faubl, Nora, Füzesi, Zsuzsanna, Horváth, Ferenc, Kiss, István, Schelling, Jörg, Terebessy, András, Voigt, Karen 11 January 2017 (has links) (PDF)
Background Physical and mental health is important for coping with the high requirements of medical studies that are associated with a higher risk for severe stress, insomnia, smoking, harmful alcohol consumption and easier access to drugs. Health behaviors of medical students influence not just their own health but also the health of their future patients. We examined whether socio-cultural factors can explain differences in students’ health status and health-promoting behaviors. Methods A multicenter cross-sectional survey in Germany (Dresden, Munich) and Hungary (Budapest, Pécs) enclosed international medical students in their 1st, 3rd and 5th academic years. The students were invited to voluntarily and anonymously complete a questionnaire on different aspects of health behavior during obligatory seminars and lectures in 2014. The response rate of the total sample was 56.2 % (n = 2935); the subgroup analysis enclosed data of German (n = 1289), Hungarian (n = 1057) and Norwegian (n = 148) students. Results A high number of Norwegian students (84.5 %) assessed their health status as very good/excellent. In comparison, only 60.3 % of the Hungarian and 70.7 % of the German participants reported a very good/excellent health status. The distributions were comparable between the study sites. Although gender, financial situation and nationality were significant health status predictors, they could explain only 8.2 % of the total variance of health status in the multivariable model. A comparably high number of Hungarian students (95.3 % vs. 67.4 % German and 56.7 % Norwegian) reported that they can currently do a lot/very much for their health. In contrast, a significant number of Norwegians (73.0 % vs. 63.7 % Hungarian and 51.5 % German) reported that they currently do a lot/very much for their health (chi2-test, p ≤ 0.001). Financial situation, study site and study year were the strongest predictors for health promotion activities (Nagelkerkes R2 = 0.06). Conclusions Based on our study, gender and study year played only a minor role in the health status and health promotion beliefs and activities of medical students. Structural (study site) and somewhat socio-cultural factors (nationality, financial situation) mainly explained the differences regarding health promoting behaviors. Obligatory, free-of-charge courses for health promotion (activity and relaxation) should be included in study curriculums.
343

Early comprehensive care of preterm infants - effects on quality of life, childhood development, and healthcare utilization: study protocol for a cohort study linking administrative healthcare data with patient reported primary data

Schmitt, Jochen, Arnold, Katrin, Druschke, Diana, Swart, Enno, Grählert, Xina, Maywald, Ulf, Fuchs, Andreas, Werblow, Andreas, Schemken, Maryan, Reichert, Jörg, Rüdiger, Mario 11 January 2017 (has links) (PDF)
Background About 9 % of all children in Germany are born preterm. Despite significant improvements of medical care, preterm infants are at a greater risk to develop short and long term health complications. Negative consequences of preterm birth include neurodevelopmental disabilities, behavioral problems or learning disorders. Most data on effects of prematurity are derived from single or multi-center studies and not population-based. Since some of the long term problems of preterm delivery are associated with a disturbed parent-child interaction originating in the neonatal period, several intervention programs became available aiming to strengthen the early parent-child relationship. However, there is insufficient knowledge regarding the psychosocial and socioeconomic impact of these interventions. Prior to introducing them into routine care, those effects have to be rigorously evaluated. The population-based cohort study EcoCare-PIn (Early comprehensive Care of Preterm Infants—effects on quality of life, childhood development, and healthcare utilization) will investigate the following primary research questions: 1) What are the short- and long-term consequences of preterm birth with regard to parental stress, parent-child relationship, childhood development, quality of life and healthcare utilization including costs? 2) Does early family-centered psychosocial care prevent the hypothesized negative consequences of preterm birth on the above mentioned outcomes? Methods/Design EcoCare-PIn examines the research questions by means of a linkage of a) pseudonymized administrative individual-level claims data from the German statutory health insurance AOK PLUS on approximately 140,000 children born between 2007 and 2013 in Saxony, and b) primary data collected from the parents/caregivers of all very low birth weight (<1,500 g; n = 1,000) and low birth weight infants (1,500 to 2,500 g; n = 5,500) and a matched sample of infants above 2,500 g birth weight (n = 10,000). Discussion In Saxony, approximately 50 % of all individuals are insured at the AOK PLUS. The linkage of patient-level administrative and primary data is a novel approach in neonatal research and probably the only way to overcome shortcomings of studies solely relying on one data source. The study results are based on an observation period of up to 8 years and will directly inform perinatal healthcare provision in Saxony and Germany as a whole.
344

Rational Structure-Based Rescaffolding Approach to De Novo Design of Interleukin 10 (IL-10) Receptor-1 Mimetics

Ruiz-Gómez, Gloria, Hawkins, John C., Philipp, Jenny, Künze, Georg, Wodtke, Robert, Löser, Reik, Fahmy, Karim, Pisabarro, M. Teresa 06 January 2017 (has links) (PDF)
Tackling protein interfaces with small molecules capable of modulating protein-protein interactions remains a challenge in structure-based ligand design. Particularly arduous are cases in which the epitopes involved in molecular recognition have a non-structured and discontinuous nature. Here, the basic strategy of translating continuous binding epitopes into mimetic scaffolds cannot be applied, and other innovative approaches are therefore required. We present a structure-based rational approach involving the use of a regular expression syntax inspired in the well established PROSITE to define minimal descriptors of geometric and functional constraints signifying relevant functionalities for recognition in protein interfaces of non-continuous and unstructured nature. These descriptors feed a search engine that explores the currently available three-dimensional chemical space of the Protein Data Bank (PDB) in order to identify in a straightforward manner regular architectures containing the desired functionalities, which could be used as templates to guide the rational design of small natural-like scaffolds mimicking the targeted recognition site. The application of this rescaffolding strategy to the discovery of natural scaffolds incorporating a selection of functionalities of interleukin-10 receptor-1 (IL-10R1), which are relevant for its interaction with interleukin-10 (IL-10) has resulted in the de novo design of a new class of potent IL-10 peptidomimetic ligands.
345

Indicators and Determinants of Small-Scale Bamboo Commercialization in Ethiopia

Endalamaw, Tefera B., Lindner, André, Pretzsch, Jürgen 28 November 2013 (has links)
Bamboo is an abundant resource in Ethiopia and has a great potential for commercialization, which can drive rural development. In view of these realities, this study analyzed the state and determinants of small-scale bamboo commercialization in Ethiopia. Data were collected from three major bamboo-growing districts (Awi, Sidama, and Sheka) and four urban centers (Masha, Hawassa, Bahir Dar, and Addis Ababa) via semi-structured interviews, group discussions, and questionnaire surveys with key actors along the value chain. Results revealed distinctive differences in proportion of cash income, value chain structure, and management engagement among the districts. Percentages of cash income were 60.15, 42.60, and 9.48 at Awi, Sidam, and Sheka, respectively. Differences were statistically significant between Sheka and both other districts (p = 0.05), but not between Awi and Sidama. The value chain structure showed that compared with Sheka, Awi and Sidama have a relatively large number of actors involved. The major factors explaining commercialization differences among regions were distance to market and presence of alternative forest products. Within Sheka, households with larger family size, higher education attainment, and access to training reportedly engaged more in commercial extraction. Therefore, we conclude that development of infrastructure for linking resource and consumer centers and expansion of extension education among producers may enhance the commercial engagement of producers and improve the accessibility of bamboo resources for commercial production.
346

Hes3 regulates cell number in cultures from glioblastoma multiforme with stem cell characteristics

Park, Deric M., Jung, Jinkyu, Masjkur, Jimmy, Makrogkikas, Stylianos, Ebermann, Doreen, Saha, Sarama, Rogliano, Roberta, Paolillo, Nicoletta, Pacioni, Simone, McKay, Ron D., Poser, Steve, Androutsellis-Theotokis, Andreas 28 November 2013 (has links)
Tumors exhibit complex organization and contain a variety of cell populations. The realization that the regenerative properties of a tumor may be largely confined to a cell subpopulation (cancer stem cell) is driving a new era of anti-cancer research. Cancer stem cells from Glioblastoma Multiforme tumors express markers that are also expressed in non-cancerous neural stem cells, including nestin and Sox2. We previously showed that the transcription factor Hes3 is a marker of neural stem cells, and that its expression is inhibited by JAK activity. Here we show that Hes3 is also expressed in cultures from glioblastoma multiforme which express neural stem cell markers, can differentiate into neurons and glia, and can recapitulate the tumor of origin when transplanted into immunocompromised mice. Similar to observations in neural stem cells, JAK inhibits Hes3 expression. Hes3 RNA interference reduces the number of cultured glioblastoma cells suggesting a novel therapeutic strategy.
347

Effect of language task demands on the neural response during lexical access: a functional magnetic resonance imaging study

Gan, Gabriela, Büchel, Christian, Isel, Frédéric 28 November 2013 (has links)
This study examined the effects of linguistic task demands on the neuroanatomical localization of the neural response related to automatic semantic processing of concrete German nouns combining the associative priming paradigm with functional magnetic resonance imaging (fMRI). To clarify the functional role of the inferior frontal gyrus (IFG) for semantic processing with respect to semantic decision making compared to semantic processing per se, we used a linguistic task that involved either a binary decision process (i.e., semantic categorization; Experiment 1) or not (i.e., silently thinking about a word's meaning; Experiment 2). We observed associative priming effects indicated as neural suppression in bilateral superior temporal gyri (STG), anterior cingulate cortex (ACC), occipito-temporal brain areas, and in medial frontal brain areas independently of the linguistic task. Inferior parietal brain areas were more active for silently thinking about a word's meaning compared to semantic categorization. A conjunction analysis of linguistic task revealed that both tasks activated the same left-lateralized occipito-temporo-frontal network including the IFG. Contrasting neural associative priming effects across linguistic task demands, we found a significant interaction in the right IFG. The present fMRI data give rise to the assumption that activation of the left inferior frontal gyrus (LIFG) in the semantic domain might be important for semantic processing in general and not only for semantic decision making. These findings contrast with a recent study regarding the role of the LIFG for binary decision making in the lexical domain (Wright et al. 2011).
348

Brominated Skeletal Components of the Marine Demosponges, Aplysina cavernicola and Ianthella basta: Analytical and Biochemical Investigations

Kunze, Kurt, Niemann, Hendrik, Ueberlein, Susanne, Schulze, Renate, Ehrlich, Hermann, Brunner, Eike, Proksch, Peter, Pée, Karl-Heinz van 28 November 2013 (has links)
Demosponges possess a skeleton made of a composite material with various organic constituents and/or siliceous spicules. Chitin is an integral part of the skeleton of different sponges of the order Verongida. Moreover, sponges of the order Verongida, such as Aplysina cavernicola or Ianthella basta, are well-known for the biosynthesis of brominated tyrosine derivates, characteristic bioactive natural products. It has been unknown so far whether these compounds are exclusively present in the cellular matrix or whether they may also be incorporated into the chitin-based skeletons. In the present study, we therefore examined the skeletons of A. cavernicola and I. basta with respect to the presence of bromotyrosine metabolites. The chitin-based-skeletons isolated from these sponges indeed contain significant amounts of brominated compounds, which are not easily extractable from the skeletons by common solvents, such as MeOH, as shown by HPLC analyses in combination with NMR and IR spectroscopic measurements. Quantitative potentiometric analyses confirm that the skeleton-associated bromine mainly withstands the MeOH-based extraction. This observation suggests that the respective, but yet unidentified, brominated compounds are strongly bound to the sponge skeletons, possibly by covalent bonding. Moreover, gene fragments of halogenases suggested to be responsible for the incorporation of bromine into organic molecules could be amplified from DNA isolated from sponge samples enriched for sponge-associated bacteria.
349

Evaluation of survival in patients after pancreatic head resection for ductal adenocarcinoma

Distler, Marius, Rückert, Felix, Hunger, Maximilian, Kersting, Stephan, Pilarsky, Christian, Saeger, Hans-Detlev, Grützmann, Robert 28 November 2013 (has links)
Background: Surgery remains the only curative option for the treatment of pancreatic adenocarcinoma (PDAC). The goal of this study was to investigate the clinical outcome and prognostic factors in patients after resection for ductal adenocarcinoma of the pancreatic head. Methods: The data from 195 patients who underwent pancreatic head resection for PDAC between 1993 and 2011 in our center were retrospectively analyzed. The prognostic factors for survival after operation were evaluated using multivariate analysis. Results: The head resection surgeries included 69.7% pylorus-preserving pancreatoduodenectomies (PPPD) and 30.3% standard Kausch-Whipple pancreatoduodenectomies (Whipple). The overall mortality after pancreatoduodenectomy (PD) was 4.1%, and the overall morbidity was 42%. The actuarial 3- and 5-year survival rates were 31.5% (95% CI, 25.04%-39.6%) and 11.86% (95% CI, 7.38%-19.0%), respectively. Univariate analyses demonstrated that elevated CEA (p = 0.002) and elevated CA 19–9 (p = 0.026) levels, tumor grade (p = 0.001) and hard texture of the pancreatic gland (p = 0.017) were significant predictors of a poor survival. However, only CEA >3 ng/ml (p < 0.005) and tumor grade 3 (p = 0.027) were validated as significant predictors of survival in multivariate analysis. Conclusions: Our results suggest that tumor marker levels and tumor grade are significant predictors of poor survival for patients with pancreatic head cancer. Furthermore, hard texture of the pancreatic gland appears to be associated with poor survival.
350

Foamy Virus Budding and Release

Hütter, Sylvia, Zurnic, Irena, Lindemann, Dirk 28 November 2013 (has links)
Like all other viruses, a successful egress of functional particles from infected cells is a prerequisite for foamy virus (FV) spread within the host. The budding process of FVs involves steps, which are shared by other retroviruses, such as interaction of the capsid protein with components of cellular vacuolar protein sorting (Vps) machinery via late domains identified in some FV capsid proteins. Additionally, there are features of the FV budding strategy quite unique to the spumaretroviruses. This includes secretion of non-infectious subviral particles and a strict dependence on capsid-glycoprotein interaction for release of infectious virions from the cells. Virus-like particle release is not possible since FV capsid proteins lack a membrane-targeting signal. It is noteworthy that in experimental systems, the important capsid-glycoprotein interaction could be bypassed by fusing heterologous membrane-targeting signals to the capsid protein, thus enabling glycoprotein-independent egress. Aside from that, other systems have been developed to enable envelopment of FV capsids by heterologous Env proteins. In this review article, we will summarize the current knowledge on FV budding, the viral components and their domains involved as well as alternative and artificial ways to promote budding of FV particle structures, a feature important for alteration of target tissue tropism of FV-based gene transfer systems.

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