TU Dresden Research Articles

Sulfated glycosaminoglycan derivatives affect the bioactivity of angiogenic growth factors

Event Abstract Back to Event Sulfated glycosaminoglycan derivatives affect the bioactivity of angiogenic growth factors Linda Koehler1, Sandra Rother1, Stephanie Moeller2, Matthias Schnabelrauch2, Vera Hintze1 and Dieter Scharnweber1 1 TU Dresden, Max Bergmann Center of Biomaterials, Germany 2 INNOVENT e.V., Biomaterials Department, Germany Introduction: Sulfated glycosaminoglycans (GAGs) are promising candidates for functional bio­ma­terials since their sulfate groups modulate the binding of growth factors, thereby influencing their biological activity profile. The interaction of different GAGs with several growth factors has previously been reported. These stu­dies demonstrated a sulfation- and carbohydrate backbone-dependent binding of GAGs resulting in an influence on the interaction of these mediators with recep­tors and therefore their bioactivity[1],[2]. Angiogenic growth factors, like vascular endothelial (VEGF) and basic fibroblast growth factor (bFGF) play an important role during wound healing[3],[4]. Heparin is known to distinctly regulate VEGF and bFGF signaling by altering their interaction with the respective receptors[4],[5]. Hence we hypothesize that VEGF and bFGF interaction with different GAGs influences their bioactivity depending on their degree of sul­fa­tion (D.S.) and carbohydrate backbone. This might lead to important implications for the use of GAGs as part of biomaterials for controlling angiogenesis during wound healing in health com­pro­mised patients. Materials and Methods: The interaction of VEGF and bFGF with different sulfated hyaluronan (sHA) and chondroitin sulfate (CS) derivatives was determined via surface plasmon resonance (SPR). VEGF or bFGF were im­mobilized onto a sensor chip surface and dif­fe­rent concentrations of solute GAGs were injected to reveal their binding strength. Addi­tionally, ELISA experiments with immobilized GAGs were performed to validate the SPR results. The influence of GAGs on the capability of growth factors to bind to their receptors was again investigated by SPR, while the consequences of the GAG/growth factor interaction on bioactivity were studied in cell-based bioassays. Here pre-incubated GAG/growth factor complexes were added to the cells and growth factor-stimulated cell proliferation was de­termined. Results and Discussion: In case of bFGF the binding strength of sHA and CS derivatives reveals a strong dependence on the D.S. but not on the carbohydrate backbone of the GAG. For VEGF, however, low-sHA and high-sulfated CS showed a comparable bin­ding strength. These results imply that the different molecular geometries in the carbohydrate backbone of the GAGs might render the respec­tive sulfate groups to interact differently. This is further emphasized in investigations with TGF-β1 whe­re naturally sulfated heparin demonstrated a comparable binding strength to high sulfated CS, even though it has a lower D.S[2]. The binding of growth factors to their respective recep­tors was modulated in the presence of GAGs which implies an altered biological profile. This could be verified in cell-based bioassays, since the presence of GAGs affected the growth factor-stimulated proliferation of the cells. Conclusion: The results imply that sulfated GAGs are promising candidates to be included in biomaterial coatings for controlling angiogenesis and therefore wound hea­ling processes, which would in particular be beneficial for health com­pro­mised patients. We acknowledge financial support by the DFG [SFB Transregio 67, projects A2, A3 and Z3].

EcoTrain: The Erzgebirgsbahn's New Hybrid Railway Vehicle

Climate change is one of the greatest challenges of the 21th century. To counteract increasing temperatures and to decrease the dependency on fossil fuels various projects are currently conducted aiming at the private and all the different industrial sectors. One of them is the EcoTrain project which is an undertaking of a consortium of several project partners lead by Deutsche Bahn. Working closely with DB RegioNetz Verkehrs GmbH, the Erzgebirgsbahn, the TU Dresden, the Fraunhofer IVI as well as the TU Chemnitz, these partners explore and work on new approaches to finding solutions for an energy-efficient mass transit vehicle. The EcoTrain project aims at developing a hybrid railcar for the Erzgebirgsbahn: A standard class 642 rail vehicle is going to be converted to a cutting-edge and innovative hybrid railcar. Later on, this prototype will serve as basis for converting the entire Erzgebirgsbahn railcar fleet. This paper deals with the development of a drive train concept for the EcoTrain. Three different approaches to hybridization are explained in conjunction with their respective advantages and disadvantages. The hybridization concepts are assessed and the drive train concept of the EcoTrain is introduced. Furthermore the simulation tool IVIsion which was used to dimension the drive train components is explained along with the achieved simulation results. The paper concludes with an introduction to the so-called energy management module which is developed by Fraunhofer IVI. This module predicts the vehicle's movement along the track and calculates recommendations for energy flow and driving style based on the schedule and current position.

Multichannel 3D plotting for complex tissue equivalents and implants for defects at tissue interfaces

Event Abstract Back to Event Multichannel 3D plotting for complex tissue equivalents and implants for defects at tissue interfaces Michael Gelinsky1, Ashwini R. Akkineni1, Kathleen Schütz1, Tilman Ahlfeld1, Yvonne Förster1, Falko Doberenz1, Maja Brückner1 and Anja Lode1 1 TU Dresden, Centre for Translational Bone, Joint and Soft Tissue Research, Germany Introduction: Additive Manufacturing (AM) opens up fascinating possibilities for the generation of implants and tissue engineering (TE) constructs. 3D plotting, i. e. extrusion of pasty biomaterials at room or physiological temperature, allows utilization of a great variety of materials and incorporation of sensitive substances like drugs, growth factors or even living cells. Multichannel-3D plotting enables processing of more than one material within one construct and therefore manufacturing of complex specimens, e.g. for application at tissue interfaces and/or generation of improved tissue equivalents which closer mimic natural tissues than conventional TE strategies. We wanted to investigate whether we can load calcium phosphate cement (CPC) pastes with growth factors and combine them with biopolymer hydrogels for AM of complex scaffolds. Further questions were whether live cells can be included within the hydrogels and both materials combined in joint strands with core/shell morphology. Materials and Methods: For 3D plotting BioScaffolder 2.1 from GeSiM (Grosserkmannsdorf, Germany) was used. As CPC paste an hydroxyapatite (HA) forming α-tricalcium phosphate-based precursor mixture, suspended in a biocompatible oily phase[1], was utilized. Blends of alginate (3%) and methylcellulose (9%)[2] were used as hydrogel material. Before scaffold preparation, all materials were sterilized. After plotting of the scaffolds in air they were stabilized by immersion in 100 mM CaCl2 solution. As growth factor, VEGF (vascular endothelial GF) was used and human mesenchymal stroma cells (hMSC) for embedding experiments. For preparation of core/shell strands self-made double-nozzle extruders were applied, mounted onto the 3D plotter. The scaffolds were fully characterized including morphology, mechanical properties, VEGF release (ELISA and bioassay), cell survival (live/dead and MTT staining) and osteogenic differentiation. One type of scaffold was tested in a pilot animal study in a 5 mm femur defect in rat, stabilized with a metal plate. Results and Discussion: Combination of CPC and biopolymer hydrogel strands within one scaffold was possible. Immersion of the scaffolds after plotting in calcium ion containing media led to CPC setting and simultaneously to alginate crosslinking. Methylcellulose which improved viscosity and therefore plottability of the hydrogel paste slowly dissolves during further storage in aqueous media, creating an additional microporosity (besides the macropores = space between the strands). We could demonstrate that VEGF could be successfully incorporated in CPC as well as hydrogel strands; for mixing with CPC binding of the GF to chitosan microparticles was advantageous. GF release was much faster from hydrogel compared to CPC – and retained biological activity of released VEGF was proven with an bioassay using endothelial cells. Human MSC could be mixed into the biopolymer hydrogel blend and survived extrusion, scaffold crosslinking and additional 3 weeks of culture. Osteogenic differentiation could be induced by applying common supplements. In addition, the animal pilot study proved biocompatibility of the new type of scaffold and biological activity of the released VEGF in vivo. A novel type of core/shell strands with a stiff shell (CPC) and soft core (hydrogel) and 3D scaffolds made thereof could be manufactured using double-nozzle extruders. Such material combinations within one extruded strand open up new possibilities for dual drug loading and release. Conclusion: Multichannel 3D plotting is a versatile AM technology and allows combination of such different biomaterials like a calcium phosphate cement and a biopolymer hydrogel. Due to the mild processing conditions sensitive components like GF and living cells can be incorporated. Of special interest is the combination of different biomaterials in strands with core/shell morphology. This technology can be further developed towards more complex tissue and organ models. Saxon State Ministry for Higher Education, Research and the Arts (SMWK) for funding

Oral but not written test anxiety is related to social anxiety.

AIMTo examine the associations of test anxiety (TA) in written vs oral exam situations with social anxiety (SA).METHODSA convenience sample of 204 students was recruited at the Technische Universität Dresden (TU Dresden, Germany) and contacted via e-mail asking to complete a cross-sectional online survey based on established questionnaires. The study protocol was approved by the ethics committee of the TU Dresden. Full data of n = 96 students were available for dependent t-tests and correlation analyses on the associations of SA and TA respectively with trigger events, cognitions, safety behaviors, physical symptoms and depersonalization. Analyses were run using SPSS.RESULTSLevels of TA were higher for fear in oral exams than for fear in written exams (M = 48.1, SD = 11.5 vs M = 43.7, SD = 10.1 P < 0.001). Oral TA and SA were positively correlated (Spearman’s r = 0.343, P < 0.001; Pearson’s r = 0.38, P < 0.001) contrasting written TA and SA (Spearman’s r = 0.17, P > 0.05; Pearson’s r = 0.223, P > 0.05). Compared to written TA, trigger events were more often reported for oral TA (18.2% vs 30.3%, P = 0.007); which was also accompanied more often by test-anxious cognitions (7.9% vs 8.5%, P = 0.001), safety behavior (8.9% vs 10.3%, P < 0.001) and physical symptoms (for all, P < 0.001).CONCLUSIONWritten, but not oral TA emerged being unrelated to SA and may rather not be considered as a typical facet of SA disorder.

Microdialysis in critical size bone defects � quantitative assessment of cytokines and proteins in the early stage of fracture repair

Event Abstract Back to Event Microdialysis in critical size bone defects – quantitative assessment of cytokines and proteins in the early stage of fracture repair Yvonne Förster1, Johannes Schmidt2, Dirk K. Wissenbach3, Susanne E. Pfeiffer3, Martin Von Bergen2, 3, Stefan Kalkhof2 and Stefan Rammelt1 1 University Hospital "Carl Gustav Carus" at TU Dresden, UniversityCenter of Orthopedics and Trauma Surgery, Germany 2 Helmholtz-Centre for Environmental Research-UFZ, Department of Proteomics, Germany 3 Helmholtz-Centre for Environmental Research-UFZ, Department of Metabolomics, Germany Fracture repair is a highly complex process influenced by growth factors, cytokines and other mediators. The early stages of the bone healing are of specific interest as they are essential for later consolidation but still poorly understood. From model systems we know about the significance of single proteins, but knowledge about the processes directly within the bone defect is limited. This is also caused by a lack of methods that allow the sampling of growth factors, cytokines and metabolites in situ. Microdialysis is a promising approach to obtain time-resolved data of specific growth factors and cytokines directly from the fracture site in vivo. When combined with a comprehensive analysis of the proteins adsorbed at the catheter tip, complementary data can be gathered from the wound site of the same defect. A 5 mm defect was created in the femur of 12 adult male Wistar rats and stabilized with an internal fixator. The microdialysis catheter was placed within the defect and the wound fluid was collected continuously under anesthesia for 24 h. Twelve rats with only a soft tissue wounds without bone defects were included as controls. Samples were collected in 3 h intervals and used to quantify cytokines and growth factors by ELISA. At the end of experiment the microdialysis catheters were explanted, the proteins adsorbed to the membrane of the microdialysis catheter were extracted and were analyzed after separation by HPLC-MS/MS. The functional annotation clustering was performed using the software packages PANTHER and DAVID.[1],[2] Analysis of the wound fluid by ELISA resulted in concentration profiles for 9 different cytokines and growth factors. Detailed analysis of Interleukin-6 (IL-6) showed that the concentration rapidly increased after surgery and declined to baseline after 24 h (Fig. 1A). In contrast, the concentration of the potentially relevant chemokine CXCL7 ((C-X-C) motif ligand 7) showed a rapid decrease immediately after surgery suggesting the release of the protein from activated platelets (Fig. 1B). More than 500 proteins were identified at the membrane of the catheter. Among them 222 proteins were detected in at least 3 of 4 replicates in both groups indicating a good reliability of the method. We could detect 78 proteins that occurred either exclusively (31) or with significantly increased abundance (47) within bone defect. For the control group, only 11 proteins were exclusive or significant increased compared to the group with a bone defect (Fig. 2). The combination of microdialysis with proteomics and metabolomics is a promising approach to obtain a detailed and direct insight into the local extracellular microenvironment of a bone defect. With these methods it is possible to obtain comprehensive and time-resolved information from the early stages of fracture repair. These data are of potential use for the development of new biomaterials that are designed to enhance bone repair and regeneration of critical size defects. Fig 1: A) Protein concentration of IL-6 in the wound fluid from bone defect (n=6) and soft tissue wound (n=8). B) Protein concentration of CXCL7 in the wound fluid from bone defect (n= 4) and soft tissue wound (n=4). Fig. 2: Distribution of the identified proteins at the membrane of the catheter. For each defect scenario 4 catheters were analyzed. This study was supported by grants from Deutsche Forschungsgemeinschaft Transregio 67 (subprojects B1, B5, and Z4). The authors thank Ute Hempel, Carolin Preissler, Sven Baumann, and Jacqueline Kober for technical assistance.

Active flow control system integration into a CFRP flap

Investigations in the past show the considerable potential of active flow control (AFC) to enhance the aircraft aerodynamic performance. This publication describes the work carried out regarding the integration of an AFC system into a CFRP flap for Next Generation Aircraft considering operational aspects. Based on a two-stage fluidic AFC actuator, a system integration concept is developed. Robustness, simplicity and maintainability are the main drivers for the integration work. Using genetic and evolutionary multi-objective optimization the most promising flap concept regarding lightweight design and integration is developed at TU Dresden ILR. This concept is numerically sized and designed in detail. The concept feasibility is shown by a 2-m span full-scale demonstrator at Airbus Group Innovations. This demonstrator is successfully tested regarding system operational capability as well as for static and fatigue performance. To investigate the structural influence of AFC blowout slits within the upper flap surface, an extensive static and dynamic coupon test program is conducted at TU Dresden ILK and TU Braunschweig IFL. In parallel, analytic and numeric methods are used to verify stress concentration within the slotted area by TU Dresden ILR.

New measurements of multilayer insulation at variable cold temperature and elevated residual gas pressure

New MLI measurements at the TU Dresden flow type calorimeter have been carried out. Specimens of 20 layer double side aluminized polyester film were tested. A cylindrical cold surface of 0.9 m2 is held at the desired cold boundary temperature between approximately 30 K and 300 K. The heat transfer through the MLI is measured by recording the mass flow as well as the inlet and the outlet temperature of the cooling fluid. Measurements at varied cold boundary temperatures have been performed. Moreover the effect of an additional vacuum degradation - as it might occur by decreasing getter material performance in real systems at elevated temperatures - is studied by a controlled inlet of nitrogen gas. Thus the vacuum pressure was varied over a range of 10-7 mbar to 10-2 mbar. Different cold boundary temperatures between 35 K and 110 K were investigated. Test results for 20 layer MLI are presented.

Towards Next Generation Sequential and Parallel SAT Solvers

This thesis focuses on improving the SAT solving technology. The improvements focus on two major subjects: sequential SAT solving and parallel SAT solving. To better understand sequential SAT algorithms, the abstract reduction system Generic CDCL is introduced. With Generic CDCL, the soundness of solving techniques can be modeled. Next, the conflict driven clause learning algorithm is extended with the three techniques local look-ahead, local probing and all UIP learning that allow more global reasoning during search. These techniques improve the performance of the sequential SAT solver Riss. Then, the formula simplification techniques bounded variable addition, covered literal elimination and an advanced cardinality constraint extraction are introduced. By using these techniques, the reasoning of the overall SAT solving tool chain becomes stronger than plain resolution. When using these three techniques in the formula simplification tool Coprocessor before using Riss to solve a formula, the performance can be improved further. Due to the increasing number of cores in CPUs, the scalable parallel SAT solving approach iterative partitioning has been implemented in Pcasso for the multi-core architecture. Related work on parallel SAT solving has been studied to extract main ideas that can improve Pcasso. Besides parallel formula simplification with bounded variable elimination, the major extension is the extended clause sharing level based clause tagging, which builds the basis for conflict driven node killing. The latter allows to better identify unsatisfiable search space partitions. Another improvement is to combine scattering and look-ahead as a superior search space partitioning function. In combination with Coprocessor, the introduced extensions increase the performance of the parallel solver Pcasso. The implemented system turns out to be scalable for the multi-core architecture. Hence iterative partitioning is interesting for future parallel SAT solvers. Constraints (2015) 20:504–505 DOI 10.1007/s10601-015-9226-6 * Norbert Manthey norbert.manthey@tu-dresden.de 1 TU Dresden, Dresden, Germany The implemented solvers participated in international SAT competitions. In 2013 and 2014 Pcasso showed a good performance. Riss in combination with Coprocessor won several first, second and third prices, including two Kurt-Godel-Medals. Hence, the introduced algorithms improved modern SAT solving technology. School: TU Dresden Supervisors: Prof. Steffen Holldober Graduated: Monday, December 1, 2014 Link to full text: http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-158672 Notes: Nominated for ACP Doctoral Research Award, and GI-Dissertationspreis 2014 Constraints (2015) 20:504–505 505

European Resuscitation Council Guidelines for Resuscitation 2015: Section 7. Resuscitation and support of transition of babies at birth

Department of Neonatology, The James Cook University Hospital, Middlesbrough, UK Department of Paediatrics, Sint Elisabeth Hospital, Tilburg, The Netherlands Department of Women and Children’s’ Health, Padua University, Azienda Ospediliera di Padova, Padua, Italy Department of Neonatology, Charite Universitatsmedizin, Berlin, Berlin, Germany Newborn Services, John Radcliffe Hospital, Oxford University Hospitals, Oxford, UK Department of Neonatology, Medizinische Fakultat Carl Gustav Carus, TU Dresden, Germany Division of Neonatology, Medical University Graz, Graz, Austria

DOSIMETRIC PROPERTIES OF THE NEW TLD ALBEDO NEUTRON DOSEMETER AWST-TL-GD 04.

A new official albedo dosemeter based on thermoluminescent detectors has been introduced in 2015 by the individual monitoring service of the Helmholtz Zentrum München for monitoring persons who are exposed occupationally against photon and neutron radiation. To enhance the sensitivity for fast neutrons, a new badge with an enlarged albedo window has been developed at TU Dresden. The properties of the new albedo dosemeter are discussed, and the results of official intercomparisons and field calibrations are shown.

The Impact of an Assurance System on the Quality of Teaching and Learning—Using the Example of a University in Russia and One of the Universities in Germany

In this paper we consider the question of how quality assurance can have a real, positive impact on the quality of teaching and learning at universities, considering the realities of different systems—the system of control and the system of quality culture—in using the example of two universities: the KNITU-KAI in Russia and the TU Dresden in Germany. The study involved 40 lecturers of technical courses and 120 third-year students of technical courses from both universities. The authors put forward a working hypothesis that quality assurance has a positive effect on the quality of teaching and learning if it carries out its informational, motivational and administrative functions. The results have shown that the aforementioned functions are not fulfilled by both universities and a special organizational culture is not the only condition that must be met for effective evaluation efforts. In order to fulfill motivational, informational and administrative functions, it is important as well that the quality assurance system is transparent and that all participants see that the surveyed data and results lead to measures for quality development. It is equally important that all university members participate in the process of quality assurance.

Towards next generation sequential and parallel SAT solvers

This thesis focuses on improving the SAT solving technology. The improvements focus on two major subjects: sequential SAT solving and parallel SAT solving. To better understand sequential SAT algorithms, the abstract reduction system Generic CDCL is introduced. With Generic CDCL, the soundness of solving techniques can be modeled. Next, the conflict driven clause learning algorithm is extended with the three techniques local look-ahead, local probing and all UIP learning that allow more global reasoning during search. These techniques improve the performance of the sequential SAT solver Riss. Then, the formula simplification techniques bounded variable addition, covered literal elimination and an advanced cardinality constraint extraction are introduced. By using these techniques, the reasoning of the overall SAT solving tool chain becomes stronger than plain resolution. When using these three techniques in the formula simplification tool Coprocessor before using Riss to solve a formula, the performance can be improved further. Due to the increasing number of cores in CPUs, the scalable parallel SAT solving approach iterative partitioning has been implemented in Pcasso for the multi-core architecture. Related work on parallel SAT solving has been studied to extract main ideas that can improve Pcasso. Besides parallel formula simplification with bounded variable elimination, the major extension is the extended clause sharing level based clause tagging, which builds the basis for conflict driven node killing. The latter allows to better identify unsatisfiable search space partitions. Another improvement is to combine scattering and look-ahead as a superior search space partitioning function. In combination with Coprocessor, the introduced extensions increase the performance of the parallel solver Pcasso. The implemented system turns out to be scalable for the multi-core architecture. Hence iterative partitioning is interesting for future parallel SAT solvers. Constraints (2015) 20:504–505 DOI 10.1007/s10601-015-9226-6 * Norbert Manthey norbert.manthey@tu-dresden.de 1 TU Dresden, Dresden, Germany The implemented solvers participated in international SAT competitions. In 2013 and 2014 Pcasso showed a good performance. Riss in combination with Coprocessor won several first, second and third prices, including two Kurt-Godel-Medals. Hence, the introduced algorithms improved modern SAT solving technology. School: TU Dresden Supervisors: Prof. Steffen Holldober Graduated: Monday, December 1, 2014 Link to full text: http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-158672 Notes: Nominated for ACP Doctoral Research Award, and GI-Dissertationspreis 2014 Constraints (2015) 20:504–505 505

Abstract 1278: Accumulation of tolerogenic human 6-sulfo LacNAc+ dendritic cells in renal cell carcinoma is associated with poor prognosis

Abstract 6-sulfo LacNAc+ (slan) DCs, representing a myeloid human blood DC subset, produce various proinflammatory cytokines, display cytotoxic activity and efficiently stimulate natural killer (NK) cells and T lymphocytes. Recent studies demonstrated that slanDCs accumulate in metastatic tumor-draining lymph nodes from cancer patients, indicating that slanDCs may contribute to antitumor immunity. We constructed tissue microarrays from primary clear-cell renal cell carcinomas (ccRCC) and paired non-neoplastic renal tissues from 265 patients who underwent radical/partial nephrectomy in the Department of Urology, University Clinic, TU Dresden. The slanDCs were identified by immunohistochemistry using a DD2 antibody, developed in the Institute of Immunology, TU Dresden. Freshly prepared tumor-infiltrating cells from 10 specimens were used for phenotypic characterization by flow cytometry. The effects of slanDCs and T-lymphocytes isolated from freshly prepared peripheral blood mononuclear cells on ACHN, CAKI-1 and on two native ccRCC cell lines were assessed by flow-cytomtery, proliferation assays. The frequency of slanDCs in ccRCC and paired non-neoplastic renal tissues were correlated with the clinico-pathological characteristics of patients. SlanDCs were detectable in the majority of primary tumors (93.2%), metastatic lymph nodes (87.5%) and distant metastases (85.1%). A significantly (p&amp;lt;0.001) higher number of slanDCs were detected in primary ccRCC tissues (mean: 3.74 slanDC/mm2, range: 0-19.82 slanDC/mm2) compared to tumor-free tissues (mean: 1.19 slanDC/mm2, range: 0-9.9 slanDC/mm2). A higher density of slanDCs in ccRCC tissues was significantly correlated with a higher grading and stage of the primary tumor (p = 0.001 and p = 0.006 respectively), as well as with lymph node- or distant metastases (p = 0.039 and p&amp;lt;0.001, respectively). Remarkably, a higher density of slanDCs was significantly correlated with a reduced progression-free, tumor-specific or overall survival of ccRCC patients. Freshly prepared ccRCC-infiltrating slanDCs expressed HLA-DR and low densities of CD86, but CD40, CD80, CD83 and CCR7 could not be detected. Whereas the proinflammatory cytokines TNF-α and IL-12 were not found, a proportion of slanDCs showed expression of the anti-inflammatory cytokine IL-10. Further studies revealed that primary ccRCC cells efficiently impair the capacity of slanDCs to stimulate CD4+ and CD8+ T-cell proliferation and Th1 programming. In addition, ccRCC cells significantly inhibited slanDC-mediated NK cell activation. These findings indicate that higher slanDC numbers in ccRCC tissues are associated with poor prognosis. The induction of a tolerogenic phenotype in slanDCs leading to an insufficient activation of innate and adaptive antitumor immunity may represent a novel immune escape mechanism of ccRCC. Citation Format: Marieta I. Toma, Rebekka Wehner, Anja Kloß, Kati Erdmann, Susanne Fuessel, Barbara Seliger, Dorothee Brech, Elfriede Noessner, Knut Schaekel, Manfred Wirth, Gustavo Baretton, Marc Schmitz. Accumulation of tolerogenic human 6-sulfo LacNAc+ dendritic cells in renal cell carcinoma is associated with poor prognosis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1278. doi:10.1158/1538-7445.AM2015-1278

A Calorimeter for Measurements of Multilayer Insulation at Variable Cold Temperature

An improved calorimeter cryostat for MLI thermal performance measurements has been designed and put into operation at the TU Dresden. Based on a liquid helium cooled flow cryostat, it allows the setting of any cold level temperature between approx. 30K and ambient temperature. Thermal shields and all-embracing radiation guards at both ends can be kept at nearly identical temperature. This is done by means of two separate cooling circuits. Both the actual cold test surface temperature and the cooling of the mechanical support and radiation shields can be independently controlled.Insulation specimens are wrapped around a test cylinder with a surface of 0.9 m2. The heat transfer through the MLI is measured by recording the mass flow and the inlet and outlet temperature of the cooling fluid. Measurements both in horizontal and vertical orientation can be performed or compared, respectively. Moreover the effect of an additional vacuum degradation as it might occur by decreasing getter material performance in real systems at elevated temperatures can be studied by controlled inlet of an elective gas. It is reported about the design and the equipment of this cryostat and measurements of a 10 layer MLI specimen.

Convective heat transfer in a semi-closed BWR-fuel assembly in absence of water

In case of a partial drain-down or a specific boil-off scenario it can be presumed that fuel assemblies in a spent fuel pool are cooled by air. Their lower end can be blocked by residual water or debris (from containment etc.). The detailed heat and mass transfer mechanisms are yet unknown. Therefore, reliable cladding temperatures cannot be predicted. For a better understanding of the mechanisms experiments were conducted at the test facility ADELA-II at the TU Dresden. The facility simulates a quarter of a generic fuel assembly in original scale. Different experiments at low rod power levels (5W and 10W per rod) were conducted. The results show that the convective heat transfer in a fuel assembly under such boundary conditions is strongly inhibited. A stagnation region evolves where convective heat transfer inside the fuel assembly can be neglected. As a result the coolability of it depends on the heat removal from the fuel assembly box to the surrounding.

Pure chitosan microfibres for biomedical applications

Abstract Due to its excellent biocompatibility, Chitosan is a very promising material for degradable products in biomedical applications. The development of pure chitosan microfibre yarn with defined size and directional alignment has always remained a critical research objective. Only fibres of consistent quality can be manufactured into textile structures, such as nonwovens and knitted or woven fabrics. In an adapted, industrial scale wet spinning process, chitosan fibres can now be manufactured at the Institute of Textile Machinery and High Performance Material Technology at TU Dresden (ITM). The dissolving system, coagulation bath, washing bath and heating/drying were optimised in order to obtain pure chitosan fibres that possess an adequate tenacity. A high polymer concentration of 8.0–8.5% wt. is realised by regulating the dope-container temperature. The mechanical tests show that the fibres present very high average tensile force up to 34.3 N, tenacity up to 24.9 cN/tex and Young’s modulus up to 20.6 GPa, values much stronger than that of the most reported chitosan fibres. The fibres were processed into 3D nonwoven structures and stable knitted and woven textile fabrics. The mechanical properties of the fibres and fabrics enable its usage as textile scaffolds in regenerative medicine. Due to the osteoconductive properties of chitosan, promising fields of application include cartilage and bone tissue engineering.

Preliminary results of a miniaturized respiratory sensor system used under hypergravity conditions up to 9 gz

Respiratory gas analyses are used to explore the influence of increased gravity on the physiology of breathing. Due to the mass, size and intricacy of standard measurement systems, previous studies were limited to a maximum acceleration of + 5 gz (head-to-foot direction). Furthermore, no in situ mainstream measurements of oxygen and carbon dioxide concentration were possible under hypergravity conditions so far. This paper shows a first study which demonstrates a respiratory sensor system developed at the Institute for Aerospace Engineering at TU Dresden. This system is suitable for an in situ measurement of respiratory changes up to + 9 gz (maximum acceleration of jet pilots) and therefore provides a possibility for detailed physiological analyses in future. Three jet pilots were equipped with this system and accelerated under a defined profile up to 7, 8 and + 9 gz. The breathing air flow, oxygen and carbon dioxide concentration were recorded with our miniaturized solid state electrolyte gas sensors, which are also described in this paper. The analysed data show significant changes of the measured respiratory parameters depending on the G-level, the acceleration rate (G-rate of onset [g s−1]) and the examination time.

Zahlungsbereitschaften im Spirituellen Tourismus: Ergebnisse einer Befragung touristischer Kirchenbesucher

Zusammenfassung Der vorliegende Beitrag präsentiert Ergebnisse eines Forschungsprojektes des Lehrstuhls für Tourismuswirtschaft der TU Dresden zum Kirchentourismus. Im Rahmen einer empirischen Fallstudie zu zwei ausgewählten Kirchen in Sachsen sind unter Anwendung der Kontingenten Bewertungsmethode touristische Kirchenbesucher zu ihren Zahlungsbereitschaften hinsichtlich individueller Beiträge zum Kirchenerhalt sowie zu Eintrittsgeldern und Spenden befragt worden.

Satisfaction with medical treatment in patients with hand dermatitis – a cross‐sectional study

Despite the significant clinical and economic burden of hand dermatitis, data on patients' satisfaction with treatment and related determining factors are lacking. We performed a cross-sectional study using a standardized survey, including all patients with hand dermatitis treated between 12/2001 and 11/2008 at the Department of Dermatology, TU Dresden. Patients were asked about socio-demographic data, disease characteristics, occupational data, quality of life, treatment satisfaction and their treatment goals. Based on an a priori model, possible impact factors on treatment satisfaction were analyzed using regression modeling. Of 382 contacted patients, 215 agreed to participate in the study (133 [61.3%] female). The mean age was 42 years. 155 patients (72.1%) had had severe or very severe hand dermatitis in the past. The majority of the patients were satisfied with the medical treatment. Treatment satisfaction was determined by the impression of professional competence (p < 0.001), physicians' empathy (p < 0.001), sufficient information on course, prognosis, and treatment options (p < 0.001), the patients' self-treatment competency (p < 0.001), quality of life (p = 0.007), as well as on the severity of hand dermatitis (p < 0.001). The data point out that in the therapy of chronic hand dermatitis, along with professional competence, the physicians' empathy, provision of sufficient information about the disease, and teaching self-treatment competency play a prominent role in improving the treatment satisfaction of the patients.

How can we prevent postoperative pulmonary complications?

aDepartment of Anesthesiology and Intensive Care Therapy, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstr, Dresden, Germany bDepartment of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy Correspondence to Paolo Pelosi, MD, Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Largo Rosanna Benzi 8, 16132 Genoa, Italy. E-mail: [email protected]