• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 248
  • 2
  • 2
  • Tagged with
  • 252
  • 252
  • 252
  • 248
  • 240
  • 234
  • 232
  • 232
  • 140
  • 120
  • 120
  • 120
  • 67
  • 64
  • 44
  • 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.
111

An N-terminal domain helical motif of Prototype Foamy Virus Gag with dual functions essential for particle egress and viral infectivity

Reh, Juliane, Stange, Annett, Götz, Anne, Rönitz, Marlene, Große, Arend, Lindemann, Dirk 22 January 2014 (has links)
Background: Foamy viruses (FVs) have developed a unique budding strategy within the retrovirus family. FV release requires co-expression and a highly specific interaction between capsid (Gag) and glycoprotein (Env), which cannot be complemented by heterologous Env proteins. The interaction domain in FV Env has been mapped in greater detail and resides mainly in the N-terminal tip of the cytoplasmic domain of the Env leader peptide subunit. In contrast, the corresponding domain within Gag is less well defined. Previous investigations suggest that it is located within the N-terminal part of the protein. Results: Here we characterized additional Gag interaction determinants of the prototype FV (PFV) isolate using a combination of particle release, GST pull-down and single cycle infectivity analysis assays. Our results demonstrate that a minimal PFV Gag protein comprising the N-terminal 129 aa was released into the supernatant, whereas proteins lacking this domain failed to do so. Fine mapping of domains within the N-terminus of PFV Gag revealed that the N-terminal 10 aa of PFV Gag were dispensable for viral replication. In contrast, larger deletions or structurally deleterious point mutations in C-terminally adjacent sequences predicted to harbor a helical region abolished particle egress and Gag – Env protein interaction. Pull-down assays, using proteins of mammalian and prokaryotic origin, support the previous hypothesis of a direct interaction of both PFV proteins without requirement for cellular cofactors and suggest a potential direct contact of Env through this N-terminal Gag domain. Furthermore, analysis of point mutants within this domain in context of PFV vector particles indicates additional particle release-independent functions for this structure in viral replication by directly affecting virion infectivity. Conclusions: Thus, our results demonstrate not only a critical function of an N-terminal PFV Gag motif for the essential capsid - glycoprotein interaction required for virus budding but also point out additional functions that affect virion infectivity.
112

Detecting and characterizing the highly divergent plastid genome of the nonphotosynthetic parasitic plant Hydnora visseri (Hydnoraceae)

Naumann, Julia, Der, Joshua P., Wafula, Eric K., Jones, Samuel S., Wagner, Sarah T., Honaas, Loren A., Ralph, Paula E., Bolin, Jay F., Maass, Erika, Neinhuis, Christoph, Wanke, Stefan, dePamphilis, Claude W. 08 June 2016 (has links)
Plastid genomes of photosynthetic flowering plants are usually highly conserved in both structure and gene content. However, the plastomes of parasitic and mycoheterotrophic plants may be released from selective constraint due to the reduction or loss of photosynthetic ability. Here we present the greatly reduced and highly divergent, yet functional, plastome of the nonphotosynthetic holoparasite Hydnora visseri (Hydnoraceae, Piperales). The plastome is 27 kb in length, with 24 genes encoding ribosomal proteins, ribosomal RNAs, tRNAs and a few non-bioenergetic genes, but no genes related to photosynthesis. The inverted repeat and the small single copy region are only ~1.5 kb, and intergenic regions have been drastically reduced. Despite extreme reduction, gene order and orientation are highly similar to the plastome of Piper cenocladum, a related photosynthetic plant in Piperales. Gene sequences in Hydnora are highly divergent and several complementary approaches using the highest possible sensitivity were required for identification and annotation of this plastome. Active transcription is detected for all of the protein coding genes in the plastid genome, and one of two introns is appropriately spliced out of rps12 transcripts. The whole genome shotgun read depth is 1,400X coverage for the plastome, while the mitochondrial genome is covered at 40X and the nuclear genome at 2X. Despite the extreme reduction of the genome and high sequence divergence, the presence of syntenic, long transcriptionally-active open reading frames with distant similarity to other plastid genomes and a high plastome stoichiometry relative to the mitochondrial and nuclear genomes suggests that the plastome remains functional in Hydnora visseri. A four stage model of gene reduction, including the potential for complete plastome loss, is proposed to account for the range of plastid genomes in nonphotosynthetic plants.
113

Validation and application of a core set of patient-relevant outcome domains to assess the effectiveness of multimodal pain therapy (VAPAIN): a study protocol

Kaiser, Ulrike, Kopkow, Christian, Deckert, Stefanie, Sabatowski, Rainer, Schmitt, Jochen 12 February 2016 (has links)
Introduction Multimodal pain therapy (MPT) has been established accounting for biopsychosocial consideration in diagnostic and therapy. MPT seems to be effective, but comparability of studies is limited due to diversity of study designs and outcome measurements. The presented study aims to develop a core outcome set consisting of a minimum of outcome measures deemed necessary for medical and therapeutic decision-making, which must be measured in all clinical trials and non-randomised intervention studies.
114

Adaption and Self-expression in Julie/Julia

Kanzler, Katja January 2013 (has links)
Julie/Julia stands out in several ways. What had begun, in 2002/2003, as a highly popular blog, in which New Yorker Julie Powell tracks her experience of cooking all the recipes in Julia Child’s classic cookbook Mastering the Art of French Cookery, became one of the first notable, commercially successful "blooks"—a neologism that denotes blogs adapted into books. As a visible sign of this achievement, The Ju-lie/Julia Project was awarded with the inaugural “Blooker Prize” in 2006. A few years later, Julie/Julia again pioneered in being the first blog (or blook, for that matter) to be adapted into a Hollywood movie, Nora Ephron’s Julie & Julia. In the following, I want to discuss Julie/Julia, and its adaptations from blog to book to film, as an instructive case study of life writing in the digital age.
115

Tunable Protein Stabilization In Vivo Mediated by Shield-1 in Transgenic Medaka

Froschauer, Alexander, Kube, Lisa, Kegler, Alexandra, Rieger, Christiane, Gutzeit, Herwig O. 07 January 2016 (has links) (PDF)
Techniques for conditional gene or protein expression are important tools in developmental biology and in the analysis of physiology and disease. On the protein level, the tunable and reversible expression of proteins can be achieved by the fusion of the protein of interest to a destabilizing domain (DD). In the absence of its specific ligand (Shield-1), the protein is degraded by the proteasome. The DD-Shield system has proven to be an excellent tool to regulate the expression of proteins of interests in mammalian systems but has not been applied in teleosts like the medaka. We present the application of the DD-Shield technique in transgenic medaka and show the ubiquitous conditional expression throughout life. Shield-1 administration to the water leads to concentration-dependent induction of a YFP reporter gene in various organs and in spermatogonia at the cellular level.
116

Trends in Incidence Rates during 1999-2008 and Prevalence in 2008 of Childhood Type 1 Diabetes Mellitus in GERMANY – Model-Based National Estimates

Rothe, Ulrike, Bendas , Alexander, Kiess, Wieland, Kapellen, Thomas Michael, Stange, Thoralf, Manuwald, Ulf, Salzsieder, Eckhard, Holl, Reinhard Walter, Schoffer, Olaf, Stahl-Pehe, Anna, Giani, Guido, Ehehalt, Stefan, Neu , Andreas, Rosenbauer, Joachim 18 January 2016 (has links) (PDF)
Aims To estimate the national incidence rate and trend of type 1 diabetes (T1DM) in Germany from 1999 to 2008 and the national prevalence in 2008 in the age group 0–14 years. Methods Data were taken from a nationwide registry for incident cases of T1DM in the ages 0–4 years and 3 regional registries (North-Rhine-Westphalia, Baden-Wuerttemberg and Saxony) for incident cases of T1DM in the ages 0–14 years covering 41% of the child population in Germany. The degree of ascertainment was ≥ 97% in all registries. Incident and prevalent cases were grouped by region, sex, age (0–4, 5–9, 10–14 years), and, for incident data, additionally by two 5-year periods (1999–2003, 2004–2008). Poisson regression models were fitted to the data to derive national estimates of incidence rate trends and prevalence in the age groups 5–9, 10–14 and 0–14 years. We used direct age-standardization. Results The estimated national incidence rate in 0-14-year-olds increased significantly by 18.1% (95%CI: 11.6–25.0%, p<0.001) from 1999–2003 to 2004–2008, independent of sex, corresponding to an average annual increase of 3.4% (95%-CI: 2.2–4.6%). The overall incidence rate was estimated at 22.9 per 100,000 person-years and we identified a within-country west-east-gradient previously unknown. The national prevalence in the ages 0–14 years on 31/12/2008 was estimated to be 148.1 per 100,000 persons. Conclusions The national incidence rate of childhood T1DM in Germany is higher than in many other countries around the world. Importantly, the estimated trend of the incidence rate confirms the international data of a global increase of T1DM incidences.
117

Model-Based Evaluation of Spontaneous Tumor Regression in Pilocytic Astrocytoma

Buder, Thomas, Deutsch, Andreas, Klink, Barbara, Voss-Böhme, Anja 08 June 2016 (has links) (PDF)
Pilocytic astrocytoma (PA) is the most common brain tumor in children. This tumor is usually benign and has a good prognosis. Total resection is the treatment of choice and will cure the majority of patients. However, often only partial resection is possible due to the location of the tumor. In that case, spontaneous regression, regrowth, or progression to a more aggressive form have been observed. The dependency between the residual tumor size and spontaneous regression is not understood yet. Therefore, the prognosis is largely unpredictable and there is controversy regarding the management of patients for whom complete resection cannot be achieved. Strategies span from pure observation (wait and see) to combinations of surgery, adjuvant chemotherapy, and radiotherapy. Here, we introduce a mathematical model to investigate the growth and progression behavior of PA. In particular, we propose a Markov chain model incorporating cell proliferation and death as well as mutations. Our model analysis shows that the tumor behavior after partial resection is essentially determined by a risk coefficient γ, which can be deduced from epidemiological data about PA. Our results quantitatively predict the regression probability of a partially resected benign PA given the residual tumor size and lead to the hypothesis that this dependency is linear, implying that removing any amount of tumor mass will improve prognosis. This finding stands in contrast to diffuse malignant glioma where an extent of resection threshold has been experimentally shown, below which no benefit for survival is expected. These results have important implications for future therapeutic studies in PA that should include residual tumor volume as a prognostic factor.
118

The Perception of Stress Pattern in Young Cochlear Implanted Children: An EEG Study

Vavatzanidis, Niki K., Mürbe, Dirk, Friederici, Angela D., Hahne, Anja 08 June 2016 (has links) (PDF)
Children with sensorineural hearing loss may (re)gain hearing with a cochlear implant—a device that transforms sounds into electric pulses and bypasses the dysfunctioning inner ear by stimulating the auditory nerve directly with an electrode array. Many implanted children master the acquisition of spoken language successfully, yet we still have little knowledge of the actual input they receive with the implant and specifically which language sensitive cues they hear. This would be important however, both for understanding the flexibility of the auditory system when presented with stimuli after a (life-) long phase of deprivation and for planning therapeutic intervention. In rhythmic languages the general stress pattern conveys important information about word boundaries. Infant language acquisition relies on such cues and can be severely hampered when this information is missing, as seen for dyslexic children and children with specific language impairment. Here we ask whether children with a cochlear implant perceive differences in stress patterns during their language acquisition phase and if they do, whether it is present directly following implant stimulation or if and how much time is needed for the auditory system to adapt to the new sensory modality. We performed a longitudinal ERP study, testing in bimonthly intervals the stress pattern perception of 17 young hearing impaired children (age range: 9–50 months; mean: 22 months) during their first 6 months of implant use. An additional session before the implantation served as control baseline. During a session they passively listened to an oddball paradigm featuring the disyllable “baba,” which was stressed either on the first or second syllable (trochaic vs. iambic stress pattern). A group of age-matched normal hearing children participated as controls. Our results show, that within the first 6 months of implant use the implanted children develop a negative mismatch response for iambic but not for trochaic deviants, thus showing the same result as the normal hearing controls. Even congenitally deaf children show the same developing pattern. We therefore conclude (a) that young implanted children have early access to stress pattern information and (b) that they develop ERP responses similar to those of normal hearing children.
119

Inferring Neuronal Dynamics from Calcium Imaging Data Using Biophysical Models and Bayesian Inference

Rahmati, Vahid, Kirmse, Knut, Marković, Dimitrije, Holthoff, Knut, Kiebel, Stefan J. 08 June 2016 (has links) (PDF)
Calcium imaging has been used as a promising technique to monitor the dynamic activity of neuronal populations. However, the calcium trace is temporally smeared which restricts the extraction of quantities of interest such as spike trains of individual neurons. To address this issue, spike reconstruction algorithms have been introduced. One limitation of such reconstructions is that the underlying models are not informed about the biophysics of spike and burst generations. Such existing prior knowledge might be useful for constraining the possible solutions of spikes. Here we describe, in a novel Bayesian approach, how principled knowledge about neuronal dynamics can be employed to infer biophysical variables and parameters from fluorescence traces. By using both synthetic and in vitro recorded fluorescence traces, we demonstrate that the new approach is able to reconstruct different repetitive spiking and/or bursting patterns with accurate single spike resolution. Furthermore, we show that the high inference precision of the new approach is preserved even if the fluorescence trace is rather noisy or if the fluorescence transients show slow rise kinetics lasting several hundred milliseconds, and inhomogeneous rise and decay times. In addition, we discuss the use of the new approach for inferring parameter changes, e.g. due to a pharmacological intervention, as well as for inferring complex characteristics of immature neuronal circuits.
120

The Spitzenkandidaten in the European Parliament Election Campaign Coverage 2014 in Germany, France, and the United Kingdom

Schulze, Heidi 21 June 2016 (has links) (PDF)
Elections to the European Parliament are characterised by a steady decline in voter turnout. To tackle this problem, in 2014, several groups of the European Parliament nominated pan-European Spitzenkandidaten who were expected to personalise the elections and mobilise European voters. Based on this development, this study analyses the media cov-erage of the 2014 EP elections with special focus on the role of the Spitzenkandidaten. A quantitative content analysis of European election campaign coverage in the opinion leading newspapers of three influential EU member states, Ger-many, France, and the United Kingdom was carried out. The results show large candidate- and country-specific differ-ences regarding the visibility and thematic coverage of the EP elections in general as well as the presentation of the Spitzenkandidaten. The Spitzenkandidaten were not very visible in either the German, French, or British newspaper cov-erage. With respect to the presence and media personalisation of the Spitzenkandidaten, the newspaper coverage of the EP election does not demonstrate any mobilising effect and thus does not reflect the high expectations the European Parliament attributed to the nomination of the Spitzenkandidaten.

Page generated in 0.0681 seconds