University of Duisburg-Essen

About: University of Duisburg-Essen is a education organization based out in Essen, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 16072 authors who have published 39972 publications receiving 1109199 citations.

Caloric Effects in Ferroic Materials: New Concepts for Cooling†

Abstract: Refrigeration is one of the main sinks of the German and European electricity consumption and accordingly contributes to worldwide CO2 emissions. High reduction potentials are envisaged if caloric effects in solid materials are used. The recent discovery of giant entropy changes associated with ferroelastic phase transformations promises higher efficiency. Ferroic transitions enhance the entropy change of magneto-, elasto-, baro-, and electro-caloric effects. Furthermore, because the refrigerant is in a solid state, this technology completely eliminates the need for halofluorocarbon refrigerants having a high global-warming potential. The smaller footprint for operation and the scalable mechanism open up further applications such as cooling of microsystems. While the principal feasibility of magnetocaloric refrigeration is already evident, it requires large magnetic fields (>2 T) which hampers wide industrial and commercial application. It is expected that this obstacle can be overcome by materials with lower hysteresis and by using stress- or electric fields. In order to accelerate research on ferroic cooling, the Deutsche Forschungsgemeinschaft (DFG) decided to establish the priority program SPP 1599 in April 2011. In this article we will address the major challenges for introducing ferroic materials in practical cooling applications: energy efficiency, effect size, and fatigue behavior. Solid state cooling in this sense can be based on the following “ferroic-caloric” classes of materials: ferroelastic shape memory alloys, ferromagnetic shape memory alloys, and ferroelectric materials and their possible combinations in materials with “multicaloric” effects. The open questions require the interdisciplinary collaboration of material scientists, engineers, physicists, and mathematicians.

Space-time processing for MIMO communications

Abstract: List of Contributors. Preface. Acknowledgements. 1 MIMO Wireless Channel Modeling and Experimental Characterization (Michael A. Jensen and Jon W. Wallace). 1.1 Introduction. 1.2 MIMO Channel Measurement. 1.3 MIMO Channel Models. 1.4 The Impact of Antennas on MIMO Performance. References. 2 Multidimensional Harmonic Retrieval with Applications in MIMO Wireless Channel Sounding (Xiangqian Liu, Nikos D. Sidiropoulos, and Tao Jiang). 2.1 Introduction. 2.2 Harmonic Retrieval Data Model. 2.3 Identifiability of Multidimensional Harmonic Retrieval. 2.4 Multidimensional Harmonic Retrieval Algorithms. 2.5 Numerical Examples. 2.6 Multidimensional Harmonic Retrieval for MIMO Channel Estimation. 2.7 Concluding Remarks. References. 3 Certain Computations Involving Complex Gaussian Matrices with Applications to the Performance Analysis of MIMO Systems (Ming Kang, Lin Yang, and Mohamed-Slim Alouini). 3.1 Introduction. 3.2 Performance Measures of Multiple Antenna Systems. 3.3 SomeMathematical Preliminaries. 3.4 General Calculations with MIMO Applications. 3.5 Summary. References. 4 Recent Advances in Orthogonal Space-Time Block Coding (Mohammad Gharavi-Alkhansari, Alex B. Gershman, and Shahram Shahbazpanahi). 4.1 Introduction. 4.2 Notations and Acronyms. 4.3 Mathematical Preliminaries. 4.4 MIMO System Model and OSTBC Background.8 4.5 Constellation Space Invariance and Equivalent Array-Processing-Type MIMO Model. 4.6 Coherent ML Decoding. 4.7 Exact Symbol Error Probability Analysis of Coherent ML Decoder. 4.8 Optimality Properties of OSTBCs. 4.9 Blind Decoding of OSTBCs. 4.10 Multiaccess MIMO Receivers for OSTBCs. 4.11 Conclusions. References. 5 Trace-Orthogonal Full Diversity Cyclotomic Space-Time Codes (Jian-Kang Zhang, Jing Liu, and Kon Max Wong). 5.1 Introduction. 5.2 Channel Model with Linear Dispersion Codes. 5.3 Good Structures for LD Codes: Trace Orthogonality. 5.4 Trace-orthogonal LD Codes. 5.5 Construction of Trace Orthogonal LD Codes. 5.6 Design of Full Diversity LD Codes. 5.7 Design of Full Diversity Linear Space-time Block Codes for N

TERT promoter mutations in bladder cancer affect patient survival and disease recurrence through modification by a common polymorphism

Abstract: The telomerase reverse transcriptase (TERT) promoter, an important element of telomerase expression, has emerged as a target of cancer-specific mutations. Originally described in melanoma, the mutations in TERT promoter have been shown to be common in certain other tumor types that include glioblastoma, hepatocellular carcinoma, and bladder cancer. To fully define the occurrence and effect of the TERT promoter mutations, we investigated tumors from a well-characterized series of 327 patients with urothelial cell carcinoma of bladder. The somatic mutations, mainly at positions -124 and -146 bp from ATG start site that create binding motifs for E-twenty six/ternary complex factors (Ets/TCF), affected 65.4% of the tumors, with even distribution across different stages and grades. Our data showed that a common polymorphism rs2853669, within a preexisting Ets2 binding site in the TERT promoter, acts as a modifier of the effect of the mutations on survival and tumor recurrence. The patients with the mutations showed poor survival in the absence [hazard ratio (HR) 2.19, 95% confidence interval (CI) 1.02-4.70] but not in the presence (HR 0.42, 95% CI 0.18-1.01) of the variant allele of the polymorphism. The mutations in the absence of the variant allele were highly associated with the disease recurrence in patients with Tis, Ta, and T1 tumors (HR 1.85, 95% CI 1.11-3.08). The TERT promoter mutations are the most common somatic lesions in bladder cancer with clinical implications. The association of the mutations with patient survival and disease recurrence, subject to modification by a common polymorphism, can be a unique putative marker with individualized prognostic potential.