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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.
21

Physical Properties of Polyamide-12 versus PMMA Denture Base Material

Wieckiewicz, Mieszko, Opitz, Volker, Richter, Gert, Böning, Klaus W. 07 July 2014 (has links) (PDF)
Objectives. Polyamide-12 (PA) is a flexible material suited for denture bases and clasping. This study investigated its potential aging effects with a focus on surface roughness, color stability, and elasticity. Methods. PA specimens (Valplast) of 40 × 10 × 2mm and equally measuring PMMA specimens (Palapress) as control were fabricated. Color changes after storage in air, water, coffee, and red wine (n = 10) were measured using the CIE L*a*b color specification. Elasticity after thermocycling (1000, 3000, and 7000 cycles, n = 15) was measured by three-point bending testing. Mean surface roughness (Ra) was determined after storage in the liquids mentioned above and thermocycling (n = 10). Results. Tukey’s HSD test (P < 0.05) revealed statistically significant color changes of PA in red wine (ΔE = 4.27 after 12 days, EΔE = 6.90 after 12 days) and coffee (ΔE = 3.93 after 36 days) but no color changes in PMMA. Elastic modulus of PA was 845MPa and not affected by thermocycling (Tukey’s HSD test, P > 0.81). Dry specimens showed significantly decreased elasticity (P < 0.001). Mean surface roughness (PA 0.20 μm, PMMA 0.28 μm) did not change significantly after thermocycling or storage (Mann-Whitney U-test, 0.16 < P < 0.65). Significance. PA exhibited a higher susceptibility to discoloration than PMMA. Neither surface roughness nor elasticity of PA was altered by artificial aging.
22

Salvia suspension cultures as production systems for oleanolic and ursolic acid

Haas, Christiane, Hengelhaupt, Karl-Christoph, Kümmritz, Sibylle, Bley, Thomas, Pavlov, Atanas, Steingroewer, Juliane 26 January 2017 (has links) (PDF)
Oleanolic and ursolic acid (OA and UA) are triterpenic acids with diverse biological activities that are of interest to the pharmaceutical industry. To investigate the scope for producing these compound using cell suspension cultures of Salvia species, calli from S. officinalis, S. virgata and S. fruticosa were induced using several plant growth regulator (PGR) combinations. Eleven lines were selected for suspension induction from a pool of calli. Six suspension cultures were established successfully and cultivated in the Respiration Activity MOnitoring System® (RAMOS®) to obtain online data on their growth kinetics and to establish appropriate sampling schedules for the determination of their OA and UA production. Based on their observed growth behaviour, OA and UA contents, and aggregation properties, one suspension culture from each studied Salvia species was selected for further optimisation. The μmax values for these suspension cultures ranged from 0.20 to 0.37°d-1, their OA and UA contents were greater than 1.3 and 1.2 mg g-1, respectively, and they afforded maximum volumetric yields of 21.0 mg l-1 for OA and 32.8 mg l-1 for UA. These results will be useful in the development of a refined Salvia suspension-based process for OA and UA production.
23

Large-scale gene expression profiling data of bone marrow stromal cells from osteoarthritic donors

Stiehler, Maik, Rauh, Juliane, Bünger, Cody, Jacobi, Angela, Vater, Corina, Schildberg, Theresa, Liebers, Cornelia, Günther, Klaus-Peter, Bretschneider, Henriette 27 January 2017 (has links) (PDF)
This data article contains data related to the research article entitled, "in vitro characterization of bone marrow stromal cells from osteoarthritic donors" [1]. Osteoarthritis (OA) represents the main indication for total joint arthroplasty and is one of the most frequent degenerative joint disorders. However, the exact etiology of OA remains unknown. Bone marrow stromal cells (BMSCs) can be easily isolated from bone marrow aspirates and provide an excellent source of progenitor cells. The data shows the identification of pivotal genes and pathways involved in osteoarthritis by comparing gene expression patterns of BMSCs from osteoarthritic versus healthy donors using an array-based approach.
24

Modeling of plant in vitro cultures – overview and estimation of biotechnological processes

Maschke, Rüdiger W., Geipel, Katja, Bley, Thomas 25 January 2017 (has links) (PDF)
Plant cell and tissue cultivations are of growing interest for the production of structurally complex and expensive plant-derived products, especially in pharmaceutical production. Problems with up-scaling, low yields and high-priced process conditions result in an increased demand for models to provide comprehension, simulation, and optimization of production processes. In the last 25 years, many models have evolved in plant biotechnology; the majority of them are specialized models for a few selected products or nutritional conditions. In this article we review, delineate, and discuss the concepts and characteristics of the most commonly used models. Therefore, the authors focus on models for plant suspension and submerged hairy root cultures. The article includes a short overview of modeling and mathematics and integrated parameters, as well as the application scope for each model. The review is meant to help researchers better understand and utilize the numerous models published for plant cultures, and to select the most suitable model for their purposes.
25

M-DC8+ Leukocytes – A Novel Human Dendritic Cell Population

Schäkel, Knut, Poppe, Claudia, Mayer, Elfriede, Federle, Christine, Riethmüller, Gert, Rieber, Ernst Peter 26 February 2014 (has links) (PDF)
Dendritic cells (DC) constitute a heterogeneous leukocyte population having in common a unique capacity to induce primary T cell responses and are therefore most attractive candidates for immunomodulatory strategies. Two populations of blood DC (CD11c+ CD123dim and CD11c– CD123high) have been defined so far. However, their direct isolation for experimental purposes is hampered by their low frequency and by the lack of selective markers allowing large scale purification from blood. Here we describe the monoclonal antibody (mAb) M-DC8, which was generated by immunizing mice with highly enriched blood DC. This mAb specifically reacts with 0.2–1% of blood leukocytes and enables their direct isolation by a one-step immunomagnetic procedure from fresh mononuclear cells. These cells can be differentiated from T cells, B cells, NK cells and monocytes using lineage-specific antibodies. M-DC8+ cells express HLA class II molecules, CD33 and low levels of the costimulatory molecules CD86 and CD40. Upon in vitro culture M-DC8+ cells spontaneously mature into cells with the phenotype of highly stimulatory cells as documented by the upregulation of HLA-DR, CD86 and CD40; in parallel CD80 expression is induced. M-DC8+ cells display an outstanding capacity to present antigen. In particular, they proved to be excellent stimulators of autologous mixed leukocyte reaction and to activate T cells against primary antigens such as keyhole limpet hemocyanin. Furthermore, they induce differentiation of purified allogeneic cytotoxic T cells into alloantigen-specific cytotoxic effector cells. While the phenotypical analysis reveals similarities with the two known blood DC populations, the characteristic expression of Fc=γRIII (CD16) and the M-DC8 antigen clearly defines them as a novel population of blood DC. The mAb M-DC8 might thus be a valuable tool to determine circulating DC for diagnostic purposes and to isolate these cells for studies of antigen-specific T cell priming. / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
26

Compensation for chronic oxidative stress in ALADIN null mice

Jühlen, Ramona, Peitzsch, Mirko, Gärtner, Sebastian, Landgraf, Dana, Eisenhofer, Graeme, Huebner, Angela, Koehler, Katrin 08 June 2018 (has links) (PDF)
Mutations in the AAAS gene coding for the nuclear pore complex protein ALADIN lead to the autosomal recessive disorder triple A syndrome. Triple A patients present with a characteristic phenotype including alacrima, achalasia and adrenal insufficiency. Patient fibroblasts show increased levels of oxidative stress, and several in vitro studies have demonstrated that the nucleoporin ALADIN is involved in both the cellular oxidative stress response and adrenal steroidogenesis. It is known that ALADIN knock-out mice lack a phenotype resembling human triple A syndrome. The objective of this study was to determine whether the application of chronic oxidative stress by ingestion of paraquat would generate a triple A-like phenotype in ALADIN null mice. Adult male mice were fed either a paraquat (0.25 g/kg diet) or control diet for 11 days. After application of chronic oxidative stress, ALADIN knock-out mice presented with an unexpected compensated glutathione metabolism, but lacked a phenotype resembling human triple A syndrome. We did not observe increased levels of oxidative stress and alterations in adrenal steroidogenesis in mice depleted for ALADIN. This study stresses the species-specific role of the nucleoporin ALADIN, which in mice involves a novel compensatory mechanism for regulating the cellular glutathione redox response.
27

Growth kinetics of a Helianthus annuus and a Salvia fruticosa suspension cell line: Shake flask cultivations with online monitoring system

Geipel, Katja, Socher, Maria Lisa, Haas, Christiane, Bley, Thomas, Steingroewer, Juliane 15 November 2016 (has links) (PDF)
Plants produce a variety of secondary metabolites, e.g. to defend themselves against herbivores or to attract pollinating insects. Plant cell biotechnology offers excellent opportunities in order to use such secondary plant metabolites to produce goods with consistent quality and quantity throughout the year, and therefore to act independently from biotic and abiotic environmental factors. This article presents results of an extensive study of plant cell in vitro cultivation in a modern shake flask system with non-invasive online respiration activity monitoring unit. Comprehensive screening experiments confirm the successful transfer of a model culture (sunflower suspension) into the shake flask monitoring device and the suitability of this respiration activity monitoring unit as qualified tool for screening of plant in vitro cultures (sunflower and sage suspension). The authors demonstrate deviations between online and offline data due to varying water evaporation from different culture flask types. The influence of evaporation on growth-specific parameters thereby rises with increasing cultivation time. Furthermore, possibilities to minimize the impact of evaporation, either by adjusting the inlet air moisture or by measuring the evaporation in combination with an appropriate correction of the measured growth values, are shown.
28

Multipose Binding in Molecular Docking

Atkovska, Kalina, Samsonov, Sergey A., Paszkowski-Rogacz, Maciej, Pisabarro, M. Teresa 09 July 2014 (has links) (PDF)
Molecular docking has been extensively applied in virtual screening of small molecule libraries for lead identification and optimization. A necessary prerequisite for successful differentiation between active and non-active ligands is the accurate prediction of their binding affinities in the complex by use of docking scoring functions. However, many studies have shown rather poor correlations between docking scores and experimental binding affinities. Our work aimed to improve this correlation by implementing a multipose binding concept in the docking scoring scheme. Multipose binding, i.e., the property of certain protein-ligand complexes to exhibit different ligand binding modes, has been shown to occur in nature for a variety of molecules. We conducted a high-throughput docking study and implemented multipose binding in the scoring procedure by considering multiple docking solutions in binding affinity prediction. In general, improvement of the agreement between docking scores and experimental data was observed, and this was most pronounced in complexes with large and flexible ligands and high binding affinities. Further developments of the selection criteria for docking solutions for each individual complex are still necessary for a general utilization of the multipose binding concept for accurate binding affinity prediction by molecular docking.
29

Fear Processing in Dental Phobia during Crossmodal Symptom Provocation: An fMRI Study

Hilbert, Kevin, Evens, Ricarda, Maslowski, Nina Isabel, Wittchen, Hans-Ulrich, Lüken, Ulrike 09 July 2014 (has links) (PDF)
While previous studies successfully identified the core neural substrates of the animal subtype of specific phobia, only few and inconsistent research is available for dental phobia. These findings might partly relate to the fact that, typically, visual stimuli were employed. The current study aimed to investigate the influence of stimulus modality on neural fear processing in dental phobia. Thirteen dental phobics (DP) and thirteen healthy controls (HC) attended a block-design functional magnetic resonance imaging (fMRI) symptom provocation paradigm encompassing both visual and auditory stimuli. Drill sounds and matched neutral sinus tones served as auditory stimuli and dentist scenes and matched neutral videos as visual stimuli. Group comparisons showed increased activation in the insula, anterior cingulate cortex, orbitofrontal cortex, and thalamus in DP compared to HC during auditory but not visual stimulation. On the contrary, no differential autonomic reactions were observed in DP. Present results are largely comparable to brain areas identified in animal phobia, but also point towards a potential downregulation of autonomic outflow by neural fear circuits in this disorder. Findings enlarge our knowledge about neural correlates of dental phobia and may help to understand the neural underpinnings of the clinical and physiological characteristics of the disorder.
30

Forest Management Approaches for Coping with the Uncertainty of Climate Change: Trade-Offs in Service Provisioning and Adaptability

Wagner, Sven, Nocentini, Susanna, Huth, Franka, Hoogstra-Klein, Marjanke 01 August 2014 (has links) (PDF)
The issue of rapid change in environmental conditions under which ecosystem processes and human interventions will take place in the future is relatively new to forestry, whereas the provision of ecosystem services, e.g., timber or fresh water, is at the very heart of the original concept of forest management. Forest managers have developed ambitious deterministic approaches to provide the services demanded, and thus the use of deterministic approaches for adapting to climate change seem to be a logical continuation. However, as uncertainty about the intensity of climate change is high, forest managers need to answer this uncertainty conceptually. One may envision an indeterministic approach to cope with this uncertainty; but how the services will be provided in such a concept remains unclear. This article aims to explore the fundamental aspects of both deterministic and indeterministic approaches used in forestry to cope with climate change, and thereby point out trade-offs in service provisioning and adaptability. A forest owner needs to be able to anticipate these trade-offs in order to make decisions towards sustainable forest management under climate change.

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