High investment costs and a dependence on noble metal catalysts currently obstruct the large‐scale implementation of proton exchange membrane water electrolyzers (PEMWEs) for converting fluctuating ...green electricity into chemical energy via water splitting. In this context, this work presents a high‐performing and stable non‐noble metal catalyst for the hydrogen evolution reaction (HER), consisting of Mo3S132− clusters supported on nitrogen doped carbon nanotubes (NCNTs). Strikingly, a significant electrochemically induced activation of the Mo3S13‐NCNT catalyst at high current densities is observed in full cell configuration, enabling a remarkable current density of 4 A cm−2 at a cell voltage of 2.36 V. To the authors’ knowledge, this is the highest reported value to date for a PEMWE full cell using a non‐noble metal HER catalyst. Furthermore, only a minor degradation of 83 µV h−1 is observed during a stability test of 100 h constant current at 1 A cm−2, with a nearly unchanged polarization behavior after the current hold. Catalyst stability and activity are additionally analyzed via online dissolution measurements. X‐ray photoelectron spectroscopy examination of the catalyst before and after electrochemical application reveals a correlation between the electrochemical activation occurring via electrodissolution with changes in the molecular structure of the Mo3S13‐NCNT catalyst.
A remarkable current density of 4 A cm−2 at 2.36 V and minor degradation during 100 h current hold at 1 A cm−2 are demonstrated for a proton exchange membrane water electrolyzer using Mo3S132− clusters supported on nitrogen doped carbon nanotubes as a hydrogen evolution reaction catalyst. This work also reveals insights into the activation behavior of this catalyst group.
We assessed the diagnostic performance of magnetic resonance (MR) arthrography in the diagnosis of articular-sided partial-thickness and full-thickness rotator cuff tears in a large symptomatic ...population. MR arthrograms obtained in 275 patients including a study group of 139 patients with rotator cuff tears proved by arthroscopy and a control group of 136 patients with arthroscopically intact rotator cuff tendons were reviewed in random order. MR imaging was performed on a 1.0 T system (Magnetom Expert, Siemens). MR arthrograms were analyzed by two radiologists in consensus for articular-sided partial-thickness and full-thickness tears of the supraspinatus, infraspinatus, and subscapularis tendons. At arthroscopy, 197 rotator cuff tears were diagnosed, including 105 partial-thickness (93 supraspinatus, nine infraspinatus, three subscapularis) and 92 full-thickness (43 supraspinatus, 20 infraspinatus, 29 subscapularis) tendon tears. For full-thickness tears, sensitivity, specificity, and accuracy were 96%, 99%, and 98%, respectively, and for partial tears 80%, 97%, and 95%, respectively. False negative and positive assessments in the diagnosis of articular-sided partial-thickness tears were predominantly 78% (35/45) observed with small articular-sided (Ellman grade1) tendon tears. MR arthrography is highly accurate in the diagnosis of full-thickness rotator cuff tears and is accurate in the diagnosis of articular-sided partial-thickness tears. Limitations in the diagnosis of partial-thickness tears are mainly restricted to small articular-sided tears (Ellman grade 1) due to difficulties in differentiation between fiber tearing, tendinitis, synovitic changes, and superficial fraying at tendon margins.
We present here a new concept of an in-situ self-calibrated isotropic light source for the future IceCube-Gen2 neutrino detector called the Precision Optical Calibration Module (POCAM). IceCube-Gen2 ...will be a matrix of light sensors buried deep in the ice at the geographic South Pole. The timing, the location, and the amount of Cherenkov light deposited by the secondary charged particles are used to reconstruct the properties of the incident neutrinos. The reconstruction relies on a detailed detector model that includes the response of optical modules to the Cherenkov light, as well as the optical properties of the detector medium – the natural Antarctic ice. To understand these properties, both natural, and artificial light sources are already used for calibration. New calibration devices are being developed in order to improve the precision of these measurements, and reduce systematic errors. The POCAM concept is based on the principle of an inverted integrating sphere. The main components are LEDs emitting light at several wavelengths and solid-state light sensors e.g. calibrated photodiode or silicon photomultipliers to monitor the emitted light intensity. We report on the current status of the POCAM R&D.
Kurzfassung:
Das Prinzip der diffusionsgewichteten MRT (diffusion-weighted MR imaging; DWI) wurde bereits in den 1950er und 1960er Jahren beschrieben und hat sich in der Neuroradiologie als ...Standardsequenz insbesondere in der Diagnostik des akuten Schlaganfalls etabliert. Aufgrund der ausgeprägten Artefaktanfälligkeit war der Einsatz der DWI zunächst auf die Diagnostik zerebraler Erkrankungen beschränkt. Technische Weiterentwicklungen der MRT wie u.a. die Einführung der echo-planaren Bildgebung, die Verwendung von Mehrkanalkörperspulen sowie die Entwicklung von Techniken der parallelen Bildgebung ermöglichten in der jüngeren Vergangenheit jedoch die Akquisition vergleichsweise artefaktarmer, qualitativ hochwertiger, diffusionsgewichteter Bilder u.a. auch im Bereich des Abdomens. Insbesondere in der Detektion fokaler Leberläsionen konnte in den letzten Jahre eine wichtige Rolle der DWI durch zahlreiche Publikationen aufgezeigt werden. Zudem kann die DWI bei der Charakterisierung fokaler Leberläsion in Zusammenschau mit den Standardsequenzen hilfreich sein. Des weiteren wurden Einsatzmöglichkeiten der DWI in der Diagnostik diffuser Veränderungen der Leber untersucht sowie eine potentielle Rolle als "MR-Biomarker" zur Pädiktion und frühzeiten Evaluation eines Therapieansprechens maligner Tumoren.
Lernziele:
Darstellung des Grundprinzips der DWI
Vermittlung technischer Grundlagen der DWI der Leber
Darstellung der Rolle der DWI in der Detektion und Charakterisierung fokaler Leberläsionen
kurze Übersicht über den Einsatz der DWI bei diffusen Lebererkrankungen
Vorstellung der DWI als potentieller „MR-Biomarker“
Abstract
The working group for abdominal and gastrointestinal diagnosis is a group of the German Radiological Society (DRG) focusing clinically and scientifically on the diagnosis and treatment of ...the gastrointestinal tract as well as the parenchymal abdominal organs. In this article we give an up-to-date literature review of scientific radiological topics especially covered by German radiologists. The working group experts cover the most recent relevant studies concerning liver-specific contrast media with an emphasis on a new classification system for liver adenomas. Additionally studies regarding selective internal radiotherapy (SIRT) are reviewed. For the pancreas the most important tumors are described followed by an introduction to the most recently introduced functional imaging techniques. The manuscript concludes with some remarks on recent studies and concerning chronic pancreatitis as well as autoimmune pancreatitis.
Key Points:
• Different subtypes of liver adenomas with different therapeutic consequences can be differentiated by MRI
• Most recently published studies focus on liver imaging with extracelluar liver specific contrast media as well as diffusion weighted imaging. They consider this new method having a high diagnostic potential.
• For pancreatic neoplasm diagnosis diffusion – as well as perfusion – imaging is considered as a highly promising method.
Citation Format:
• Grenacher L, Juchems MS, Holzapfel K et al. A Review of Scientific Topics and Literature in Abdominal Radiology in Germany – Part 2: Abdominal Parenchymal Organs. Fortschr Röntgenstr 2016; 188: 245 – 252
Abstract
The working group for abdominal and gastrointestinal diagnosis is a group of the German Radiological Society (DRG) focusing clinically and scientifically on the diagnosis and treatment of ...the gastrointestinal tract with all parenchymatous abdominal organs. In addition to the clinical and scientific further development of abdominal radiology, the education of radiologists within this core discipline of radiology is one of the major aims. In this article we give an up-to-date literature review of scientific radiological topics especially covered by German radiologists. This manuscript focuses on the most recent literature on the diagnosis of the stomach, small bowel, colon and rectum. The review with a focus on the most recent studies published by German radiologists concludes with a synopsis of mesenterial bleeding and ischemia followed by a critical appraisal of the current literature on conventional abdominal radiography.
Key Points:
• Based on recent literature and guidelines there is a change of paradigms regarding the diagnosis of esophagus and gastric cancer towards CT, which is considered equally to endosonography.
• For small bowel imaging in Crohn’s disease ultrasound as well as MRI with a new focus on DWI are the most important imaging modalities scientifically.
• For colonic diagnosis virtual colonoscopy has replaced the conventional radiological methods. For staging of rectal carcinoma as well as for therapeutic stratification a high resolution MRI of the pelvis is of paramount interest.
• Multislice CT is considered the most important modality to assess mesenteric ischemia or bleeding.
Citation Format:
• Schreyer AG, Wessling J, Kinner S et al. A Review of Scientific Topics and Literature in Abdominal Radiology in Germany – Part 1: Gastrointestinal Tract. Fortschr Röntgenstr 2016; 188: 134 – 145
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