246 research outputs found
The effect of substrate modulus on the growth and function of matrix-embedded endothelial cells
No full textEndothelial cells (EC) are potent bioregulatory cells, modulating thrombosis, inflammation and control over mural smooth muscle cells and vascular health. The biochemical roles of EC are retained when cells are embedded within three-dimensional (3D) denatured collagen matrices. Though substrate mechanics have long been known to affect cellular morphology and function and 3D-EC systems are increasingly used as therapeutic modalities little is known about the effect of substrate mechanics on EC in these 3D systems. In this work, we examined the effect of isolated changes in modulus on EC growth and morphology, extracellular matrix gene expression, modulation of smooth muscle cell growth, and immunogenicity. EC growth, but not morphology was dependent on scaffold modulus. Increased scaffold modulus reduced secretion of smooth muscle cell growth inhibiting heparan sulfate proteoglycans (HSPGs), but had no effect on secreted growth factors, resulting in a loss of smooth muscle cell growth inhibition by EC on high modulus scaffolds. Expression of ICAM-1, VCAM-1 and induction of CD4[superscript +] T cell proliferation was reduced by increased scaffold modulus, and correlated with changes in integrin α5 expression. Expression of several common ECM proteins by EC on stiffer substrates dropped, including collagen IV(α1), collagen IV(α5), fibronectin, HSPGs (perlecan and biglycan). In contrast, expression of elastin and TIMPs were increased. This work shows even modest changes in substrate modulus can have a significant impact on EC function in three-dimensional systems. The mechanism of these changes is not clear, but the data presented here within suggests a model wherein EC attempt to neutralize changes in environmental force balance by altering ECM and integrin expression, leading to changes in effects on downstream signaling and function.National Institutes of Health (U.S.) (R01 GM49039)Else Kroner-Fresenius Stiftung (P36/07//A45/07
Th2 cells are essential for modulation of vascular repair by allogeneic endothelial cells
No full textAuthor Manuscript 2011 April 1.Background:
Endothelial cells (ECs) embedded within 3-dimensional matrices (MEEC) control lumenal inflammation and intimal hyperplasia when placed in the vascular adventitia. Matrix embedding alters endothelial immunogenicity in vitro. T-helper (Th) cell-driven host immunity is an impediment of allogeneic grafts. We aimed to identify if modulation of Th balance would affect immune compatibility and endothelial regulation of vascular repair in vivo.
Methods:
Pigs (n = 4/group) underwent carotid artery balloon injury and were left untreated (Group 1) or received perivascular porcine MEEC implants (Group 2), 12 days of cyclosporine A (CsA; Group 3), or MEEC and CsA (Group 4). Host immune reactivity was analyzed after 28 and 90 days.
Results:
MEEC treatment induced formation of EC-specific immunoglobulin (Ig) G1 antibodies (41 ± 6 mean fluorescence intensity [MFI]) and differentiation of host splenocytes into Th2, but not Th1, cytokine-producing cells (interleukin [IL]-4, 242 ± 102; IL-10, 273 ± 114 number of spots). Concomitant CsA therapy reduced IgG1 antibody frequency (25 ± 2 MFI; p < 0.02) and Th2-cytokine producing splenocytes upon MEEC treatment (IL-4, 157 ± 19; IL-10, 124 ± 26 number of spots; p < 0.05). MEECs inhibited luminal occlusion 28 and 90 days after balloon injury (12 ± 7%) vs untreated controls (68 ± 14%; p < 0.001) but to a lesser extent with concomitant CsA treatment (34 ± 13%; p < 0.02 vs Group 2).
Conclusions:
MEECs do not induce a significant Th1-driven immune response but do enhance differentiation of splenocytes into cells producing Th2 cytokine. Reduction in this Th2 response reduces the vasoregulatory effects of allogeneic ECs after injury
Modelling Interregional Trade of Energy Crops in Eastern Germany
No full textRenewable resources gain in importance in our modern society. The line of reasoning is based on their positive effects on agriculture, the environment and the economy. To support renewable energy from biomass the EU promotes the cultivation of energy crops. A spatial equilibrium model is applied based on the concept of maximizing net welfare, to provide information whether energy crop production competes with food production for land area. The Model of Interregional Trade of Energy Crops (ITEC) refers to Eastern Germany and adjacent areas of Poland. First results show that the regions have enough feedstocks to meet the required demand for food and biofuel production. In many cases both food crops and biofuels are either traded on interregional basis or exported to "Rest of Europe" indicating that there is no competition between food and energy crops. Only green maize for biogas production strongly competes in areas where the crop is required as feed for cattle.Energy crops, spatial equilibrium analysis, interregional trade, International Relations/Trade,
In-situ study of emerging metallicity and memory effect on ion-beam bombarded strontium titanate surface:
No full textIn this work we present an investigation of the occurrence of conductivity on the surface of SrTiO3 due to argon ion bombardment. We created a model to describe this process and found that the temperature during the ion milling is a crucial factor for the conductivity. Depending on the temperatures we found surface carrier densities ranging from 1.5*10^18 to 2.6*10^20cm^-3 by just analyzing the conductivity behavior.
Clustering of vacancies goes along with temperature and affects the conductivity significantly. Furthermore we found that ion milling is a gentle way create vacancies because the clustering rate is small compared to annealing samples in high vacuum. The amount of clusters at room temperature was measured to be around 3-4 times higher than at -140C.
We found that samples with a conducting surface change their resistance over time at room temperature due to the ongoing process of oxygen vacancy clustering. This effect may be suppressed by decreasing the temperature.
The bistable switching behavior in oxygen deficient SrTiO3 is shown without any additional doping. The vacancy migration is the major mechanism behind this memory effect. Comparing this behavior with annealed samples in high vacuum shows that the therein present amount of vacancy clusters must be much larger and has a negative effect on the bistable switching behavior.M.S.Includes bibliographical references (p. 83-87)by Heiko Gros
Handle with Care : Implementation of the List Experiment and Crosswise Model in a Large-Scale Survey on Academic Misconduct
No full textAcknowledgments We thank the anonymous reviewers as well as Alexander Ehlert, Isabel Raabe, and Justus Rathmann for their concise comments and constructive feedback on our work. Co-authors in alphabetical order. Study Design: Julia Jerke, David Johann, Heiko Rauhut, Kathrin Thomas, Antonia Velicu. Coding and Analysis: Julia Jerke, David Johann, Kathrin Thomas, Antonia Velicu. First draft: Julia Jerke, Heiko Rauhut, Kathrin Thomas, Antonia Velicu. Revisions: David Johann, Kathrin Thomas, Antonia Velicu. Final approval of the paper: Julia Jerke, David Johann, Heiko Rauhut, Kathrin Thomas, Antonia Velicu. Funding Information: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research is supported by the Swiss National Science Foundation (SNSF), Starting Grant “CONCISE” BSSGIO 155981 of Heiko Rauhut.Peer reviewe
The Definitive Guide to NetBeans Platform
No full textThe Definitive Guide to NetBeans(t) Platform is a thorough and definitive introduction to the NetBeans Platform, covering all its major APIs in detail, with relevant code examples used throughout. The original German book on which this title is based was well received. The NetBeans Platform Community has put together this English translation, which author Heiko Bock updated to cover the latest NetBeans Platform 6.5 APIs. With an introduction by known NetBeans Platform experts Jaroslav Tulach, Tim Boudreau, and Geertjan Wielenga, this is the most up-to-date book on this topic at the moment. Al
An adaptive system for patient-controlled analgesia vol.1
No full textVolume 2 is the actual data. Please contact the author for this information. Heiko Rudolph [[email protected]] http://www.set.rmit.edu.au/~e55643/Deposited with permission of the author. © 1995 Dr. Heiko E. R. Rudolph.Patient-Controlled Analgesia (PCA) has become accepted as an important means of self-regulated relief from post-surgical pain. In commonly used PCA systems, patients use a hand-held push-button to indicate the presence of pain and initiate a predetermined bolus of drug infusion. A disadvantage of this system is that no means is provided to accommodate variations in the intensity of pain or the sensitivity of the patient to the analgesic in use apart from the frequency of button pushing. A fixed rate background infusion is usually an option. A new adaptive PCA system is proposed to provide improved PCA through the use a variable background infusion, the provision for an extended high range of analgesic dosages and a novel handset which allows patients to rate their pain. The total system is under the control of an expert algorithm and is proposed to overcome some of the shortcomings of current systems. (For complete abstract open document
Bicycle Ambulances in rural Uganda - Analysis of factors influencing its usage
No full textThis article reports on a study undertaken to analyze the usage of the bicycle ambulances in Uganda. Since 1997, approximately 400 bicycle ambulances have been distributed to villages in rural Uganda to improve accessibility to health centers. Approximately 20% of the population of Uganda have to travel more than 5 km to a health center, in a country where most transportation is by foot. A bicycle ambulance is a bicycle with an attached trailer used to transport seriously sick patients up to 15 km. The author conducted guided interviews with receivers and the distributors of bicycle ambulances in selected villages. Factors have been defined that influence the usage of bicycle ambulances, including individual village characteristics, the features of the bicycle ambulance, the system of distribution, and the organization of the groups using the bicycle ambulances. The distance to the health center, nor the distance to the main road and quality of the road itself significantly influenced the usage of the bicycle ambulance. The frequency of usage of the bicycle ambulances was limited to a few cases in a month or year. The only significant influence on the frequency of usage was observed based on the different organizational structures of the bicycle ambulance groups. The author considers some of the barriers to use, including long distances to health centers and costs of repairs, but notes that these and other barriers can be overcome through the positive attitude of group members
Bicycle Ambulances in rural Uganda - Analysis of factors influencing its usage
No full textThis article reports on a study undertaken to analyze the usage of the bicycle ambulances in Uganda. Since 1997, approximately 400 bicycle ambulances have been distributed to villages in rural Uganda to improve accessibility to health centers. Approximately 20% of the population of Uganda have to travel more than 5 km to a health center, in a country where most transportation is by foot. A bicycle ambulance is a bicycle with an attached trailer used to transport seriously sick patients up to 15 km. The author conducted guided interviews with receivers and the distributors of bicycle ambulances in selected villages. Factors have been defined that influence the usage of bicycle ambulances, including individual village characteristics, the features of the bicycle ambulance, the system of distribution, and the organization of the groups using the bicycle ambulances. The distance to the health center, nor the distance to the main road and quality of the road itself significantly influenced the usage of the bicycle ambulance. The frequency of usage of the bicycle ambulances was limited to a few cases in a month or year. The only significant influence on the frequency of usage was observed based on the different organizational structures of the bicycle ambulance groups. The author considers some of the barriers to use, including long distances to health centers and costs of repairs, but notes that these and other barriers can be overcome through the positive attitude of group members
Glucocorticoid-remediable aldosteronism in a young adult with a family history of Conn's syndrome
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