• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 566
  • 5
  • 4
  • Tagged with
  • 575
  • 554
  • 412
  • 390
  • 382
  • 348
  • 303
  • 298
  • 295
  • 295
  • 236
  • 231
  • 222
  • 222
  • 185
  • 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.
131

The Dox-pDC - A murine conditionally immortalized plasmacytoid dendritic cell line with native immune profile

Thieme, Sebastian, Holzbaur, Alexander, Wiedemuth, Ralf, Binner, Aline, Navratiel, Katrin, Anastassiadis, Konstantinos, Brenner, Sebastian, Richter, Cornelia 11 June 2018 (has links) (PDF)
Plasmacytoid dendritic cells (pDC) constitute a very rare blood cell population and play a significant role in immune response and immune-mediated disorders. Investigations on primary pDCs are hindered not only due to their rarity but also because they represent a heterogeneous cell population which is difficult to culture ex vivo. We generated a conditionally immortalized pDC line (Dox-pDC) from mice with Doxycycline-inducible SV40 Large T Antigen with a comparable immune profile to primary pDCs. The Dox-pDC secrete pro- and anti-inflammatory cytokines upon Toll-like receptor 9 stimulation and upregulate their MHCI, MHCII and costimulatory molecules. Further, the Dox-pDC activate and polarize naïve T cells in vivo and in vitro in response to the model antigen Ovalbumin. Due to their long-term culture stability and their robust proliferation Dox-pDC represent a reliable alternative to primary mouse pDC.
132

The Occurrence of Rupture in Deep-Drawing of Paperboard

Wallmeier, Malte, Hauptmann, Marek, Majschak, Jens-Peter 01 August 2018 (has links) (PDF)
The production of paperboard packaging components in fast-running machines requires reliability of the production process. Boundaries for the process parameters and constraints for the geometry of the tools require investigation to determine dependable configurations. This paper aimed to investigate the relationships between process parameters, tool geometry, and the occurrence of rupture in the deep-drawing process of paperboard. Different types of ruptures in various phases of the process were distinguished and linked to their specific cause. An extensive experimental investigation with multiple variables of influence was conducted. A logistic regression model was used to describe the experimental data and was statistically validated. The blankholder force was found to be the most influential parameter. Interactions between the parameters blankholder force, punch velocity, and punch diameter were recognized. A high punch velocity can reduce the probability of rupture when the punch diameter is adjusted.
133

Performance Features of a Stationary Stochastic Novikov Engine

Schwalbe, Karsten, Hoffmann, Karl Heinz 22 January 2018 (has links) (PDF)
In this article a Novikov engine with fluctuating hot heat bath temperature is presented. Based on this model, the performance measure maximum expected power as well as the corresponding efficiency and entropy production rate is investigated for four different stationary distributions: continuous uniform, normal, triangle, quadratic, and Pareto. It is found that the performance measures increase monotonously with increasing expectation value and increasing standard deviation of the distributions. Additionally, we show that the distribution has only little influence on the performance measures for small standard deviations. For larger values of the standard deviation, the performance measures in the case of the Pareto distribution are significantly different compared to the other distributions. These observations are explained by a comparison of the Taylor expansions in terms of the distributions’ standard deviations. For the considered symmetric distributions, an extension of the well known Curzon–Ahlborn efficiency to a stochastic Novikov engine is given.
134

Enabling and Predisposing Factors for the Utilization of Preventive Dental Health Care in Migrants and Non-Migrants in Germany

Brzoska, Patrick, Erdsiek, Fabian, Waury, Dorothee 27 October 2017 (has links) (PDF)
Background: In many European countries including Germany, migrants utilize preventive services less frequently than the majority population. This is also true for the utilization of dental checkups. Little is known about which demographic, social, behavioral, and health-related factors influence the decision of migrants to seek preventive dental health care and how these factors differ from those in non-migrants. The aim of the present study was to examine the role of these factors among migrants and non-migrants residing in Germany. Methods: Data from cross-sectional national health surveys are used, providing information on preventive dental health behavior from n = 41,220 individuals, of which 15.0% are migrants. Andersen’s Behavioral Model of Health Services Use is the conceptual framework of the investigation. Multiple logistic regression models were applied to examine the role of different predisposing and enabling factors. Interaction terms were included in order to examine whether determinants differ between migrants and non-migrants. Average marginal effects (AMEs) are reported in addition to odds ratios (ORs) as measures of effect size which are robust against bias arising from unobserved heterogeneity. Results: Migrants are at an about 36% lower chance of utilizing regular dental checkups than non-migrants [OR = 0.64 (95% confidence interval, 95% CI: 0.61, 0.68); AME = −0.081 (95% CI = −0.093, −0.069)]. Differences are partly explained by the influence of demographic, social, behavioral, and health-related factors [adjusted OR = 0.69 (95% CI: 0.64, 0.73); AME = −0.065 (95% CI = −0.076, −0.053)]. Younger age, being male, lower socioeconomic status, a non-statutory health insurance, not living in a relationship, living in the Western part of Germany and in an urban setting, and poor limited social support were associated with a lower chance of utilizing regular dental checkups. Interaction effects could be observed for age and for the type of health insurance. Discussion: The study identifies different enabling and predisposing factors that are relevant for the utilization of dental checkups among the population in Germany, some of which differ between migrants and non-migrants. Differences are particularly pronounced for younger ages. This differs from findings on other preventive services where older migrants tend to be more disadvantaged. Additional explanatory factors such as barriers that migrants experience in the dental health care system need to be considered in order to implement patient-oriented services and to reduce disparities in access to dental prevention.
135

Using binocular rivalry to tag foreground sounds: Towards an objective visual measure for auditory multistability

Einhäuser, Wolfgang, Thomassen, Sabine, Bendixen, Alexandra 29 September 2017 (has links) (PDF)
In binocular rivalry, paradigms have been proposed for unobtrusive moment-by-moment readout of observers' perceptual experience (“no-report paradigms”). Here, we take a first step to extend this concept to auditory multistability. Observers continuously reported which of two concurrent tone sequences they perceived in the foreground: high-pitch (1008 Hz) or low-pitch (400 Hz) tones. Interstimulus intervals were either fixed per sequence (Experiments 1 and 2) or random with tones alternating (Experiment 3). A horizontally drifting grating was presented to each eye; to induce binocular rivalry, gratings had distinct colors and motion directions. To associate each grating with one tone sequence, a pattern on the grating jumped vertically whenever the respective tone occurred. We found that the direction of the optokinetic nystagmus (OKN)—induced by the visually dominant grating—could be used to decode the tone (high/low) that was perceived in the foreground well above chance. This OKN-based readout improved after observers had gained experience with the auditory task (Experiments 1 and 2) and for simpler auditory tasks (Experiment 3). We found no evidence that the visual stimulus affected auditory multistability. Although decoding performance is still far from perfect, our paradigm may eventually provide a continuous estimate of the currently dominant percept in auditory multistability.
136

Satisfaction with rehabilitative health care services among German and non-German nationals residing in Germany: a cross-sectional study

Brzoska, Patrick, Sauzet, Odile, Yilmaz-Aslan, Yüce, Widera, Teresia, Razum, Oliver 31 August 2017 (has links) (PDF)
Objectives Rehabilitation following medical conditions is largely offered as in-patient service in Germany. Foreign-national residents use rehabilitative services less often than Germans and attain less favourable treatment outcomes. These differences are independent of demographic, socioeconomic and health characteristics. Satisfaction with different aspects of rehabilitative care presumably affects the effectiveness of rehabilitative services. We compared the degree of satisfaction with different domains of the rehabilitative care process between Germans and non-German nationals residing in Germany. Methods We used data from a cross-sectional rehabilitation patient survey annually conducted by the German Statutory Pension Insurance Scheme. The sample comprises 274 513 individuals undergoing medical rehabilitation in 642 hospitals during the years 2007–2011. Participants rated their satisfaction with different domains of rehabilitation on multi-item scales. We dichotomised each scale to low/moderate and high satisfaction. For each domain, a multilevel adjusted logistic regression analysis was conducted to examine differences in the levels of satisfaction between German and non-German nationals. Average marginal effects (AMEs) and 99.5% CI were computed as effect estimates. AMEs represent differences in the probability for the occurrence of the outcome. Results Turkish nationals had a higher probability for being less satisfied with most aspects of their rehabilitation, with AMEs ranging between 0.05 (99.5% CI 0.00 to 0.09) for ‘satisfaction with psychological care’ and 0.11 (99.5% CI 0.08 to 0.14) for ‘satisfaction with treatments during rehabilitation’. Patients from former Yugoslavia and from Portugal/Spain/Italy/Greece were as satisfied as Germans with most aspects of their rehabilitation. Conclusions Turkish nationals are less satisfied with their rehabilitative care than other population groups. This may be attributable to the diversity of the population in terms of its expectations towards rehabilitation. Rehabilitative care institutions need to provide services that are sensitive to the needs of all clients. Diversity management can contribute to this process.
137

A Full Frequency-Dependent Cable Model for the Calculation of Fast Transients

Hoshmeh, Abdullah, Schmidt, Uwe 31 August 2017 (has links) (PDF)
The calculation of frequency-dependent cable parameters is essential for simulations of transient phenomena in electrical power systems. The simulation of transients is more complicated than the calculation of currents and voltages in the nominal frequency range. The model has to represent the frequency dependency and the wave propagation behavior of cable lines. The introduced model combines an improved subconductor method for the determination of the frequency-dependent parameters and a PI section wave propagation model. The subconductor method considers the skin and proximity effect in all conductors for frequency ranges up to few megahertz. The subconductor method method yields accurate results. The wave propagation part of the cable model is based on a cascaded PI section model. A modal transformation technique has been used for the calculation in the time domain. The frequency-dependent elements of the related modal transformation matrices have been fitted with rational functions. The frequency dependence of cable parameters has been reproduced using a vector fitting algorithm and has been implemented into an resistor-inductor-capacitor network (RLC network) for each PI section. The proposed full model has been validated with measured data.
138

Measuring Cognitive Load in Embodied Learning Settings

Skulmowski, Alexander, Rey, Günter Daniel 02 August 2017 (has links) (PDF)
In recent years, research on embodied cognition has inspired a number of studies on multimedia learning and instructional psychology. However, in contrast to traditional research on education and multimedia learning, studies on embodied learning (i.e., focusing on bodily action and perception in the context of education) in some cases pose new problems for the measurement of cognitive load. This review provides an overview over recent studies on embodied learning in which cognitive load was measured using surveys, behavioral data, or physiological measures. The different methods are assessed in terms of their success in finding differences of cognitive load in embodied learning scenarios. At the same time, we highlight the most important challenges for researchers aiming to include these measures into their study designs. The main issues we identified are: (1) Subjective measures must be appropriately phrased to be useful for embodied learning; (2) recent findings indicate potentials as well as problematic aspects of dual-task measures; (3) the use of physiological measures offers great potential, but may require mobile equipment in the context of embodied scenarios; (4) meta-cognitive measures can be useful extensions of cognitive load measurement for embodied learning.
139

A Single Gyroscope Can Be Used to Accurately Determine Peak Eversion Velocity during Locomotion at Different Speeds and in Various Shoes

Mitschke, Christian, Öhmichen, Matthias, Milani, Thomas L. 10 July 2017 (has links) (PDF)
Gyroscopes have been used in previous studies to measure the peak angular velocity of the shoe or foot in the frontal plane (evVel). However, it is not clear whether different test conditions (footwear hardness or locomotion speed) can influence the accuracy of evVel. The purpose of the present study was to compare the accuracy of gyroscopes and electrogoniometers when measuring evVel and the time until evVel (t_evVel) in 12 different conditions using a single axis gyroscope attached to the heel cap. Twenty-four recreational runners were instructed to walk and run on a 15-m indoor track at four locomotion speeds (1.5, 2.5, and 3.5 m/s, and individual running speed) and in three footwear conditions (low to high hardness). The gyroscope data and electrogoniometer data were sampled at a rate of 1000 Hz. Comparisons between both measurement devices showed small mean differences up to 49.8 ± 46.9 deg/s for evVel and up to 5.3 ± 3.5 ms for t_evVel. Furthermore, strong relationships between gyroscope and electrogoniometer data were found for evVel as well as for t_evVel for all conditions. It can be concluded that gyroscopes can be used to accurately determine evVel and t_evVel under a variety of conditions.
140

Diabetes-linked transcription factor HNF4α regulates metabolism of endogenous methylarginines and β-aminoisobutyric acid by controlling expression of alanine-glyoxylate aminotransferase 2

Burdin, Dmitry V., Kolobov, Alexey A., Brocker, Chad, Soshnev, Alexey A., Samusik, Nikolay, Demyanov, Anton v., Brilloff, Silke, Jarzebska, Natalia, Martens-Lobenhoffer, Jens, Mieth, Maren, Maas, Renke, Bornstein, Stefan R., Bode-Böger, Stefanie M., Gonzalez, Frank, Weiss, Norbert, Rodionov, Roman N. 21 July 2017 (has links) (PDF)
Elevated levels of circulating asymmetric and symmetric dimethylarginines (ADMA and SDMA) predict and potentially contribute to end organ damage in cardiovascular diseases. Alanine-glyoxylate aminotransferase 2 (AGXT2) regulates systemic levels of ADMA and SDMA, and also of beta-aminoisobutyric acid (BAIB)-a modulator of lipid metabolism. We identified a putative binding site for hepatic nuclear factor 4 α (HNF4α) in AGXT2 promoter sequence. In a luciferase reporter assay we found a 75% decrease in activity of Agxt2 core promoter after disruption of the HNF4α binding site. Direct binding of HNF4α to Agxt2 promoter was confirmed by chromatin immunoprecipitation assay. siRNA-mediated knockdown of Hnf4a led to an almost 50% reduction in Agxt2 mRNA levels in Hepa 1–6 cells. Liver-specific Hnf4a knockout mice exhibited a 90% decrease in liver Agxt2 expression and activity, and elevated plasma levels of ADMA, SDMA and BAIB, compared to wild-type littermates. Thus we identified HNF4α as a major regulator of Agxt2 expression. Considering a strong association between human HNF4A polymorphisms and increased risk of type 2 diabetes our current findings suggest that downregulation of AGXT2 and subsequent impairment in metabolism of dimethylarginines and BAIB caused by HNF4α deficiency might contribute to development of cardiovascular complications in diabetic patients.

Page generated in 0.1068 seconds