Nodular Regenerative Hyperplasia and Portal Hypertension in a Patient with Coeliac Disease

Nodular regenerative hyperplasia (NRH) of the liver is often associated with rheumatologic or lymphoproliferative disorders and a cause of portal hypertension in some patients. We report the case of a 71-year-old patient with celiac disease and unexplained portal hypertension. Biopsy of the liver revealed NRH as the underlying cause. The patient did not suffer from an autoimmune, rheumatologic or lymphoproliferative disease. A thrombophilic disorder that might cause NRH was ruled out. Celiac disease is often associated with mild elevation of liver enzymes and steatosis of the liver, but the association with NRH was described in only a few patients. We discuss the possible relationship of celiac disease and NRH

Improvement of safe bromine electrolytes and their cell performance in H2_{2}/Br2_{2} flow batteries caused by tuning the bromine complexation equilibrium

Hydrogen bromine redox flow batteries utilize bromine electrolytes in their positive half cell, offering capacities larger than 100 Ah L$^{-1}$. Addition of quaternary ammonium compounds, so-called bromine complexing agents (BCA), may increase safety as they reduce the vapour pressure of bromine in the posolyte. However, they have not been applied so far. They (a) interact with perfluorosulfonic acid membranes leading to significant reduction of membrane conductivity and (b) they form a low conductive ionic liquid with polybromides, leading to high overvoltage if the formation happens at the electrode. In this work a solution to this problem is proposed by an excess addition of Br$_{2}$ to these electrolytes. The excess bromine leads to a permanent bromine fused salt phase in the tank. Bromine formed in the cell stays in the aqueous phase and bromine transfer between the two phases happens in the tank. Transfer of Br2 without the transfer of [BCA]$^{+}$ cations exists between the phases, while [C2Py]$^{+}$ cations remain in the fused salt and do not influence cell performance. For the first time a posolyte capacity of 179.6 Ah L$^{-1}$ based on 7.7 M hydrobromic acid with BCA is achieved compared to previous investigations with e.g. 53.9 Ah L$^{-1}$

Cycle behaviour of hydrogen bromine redox flow battery cells with bromine complexing agents

Bromine complexing agents (BCA) are used to improve the safety of aqueous bromine electrolytes versus bromine outgassing in bromine electrolytes. In this work, cycling performance of hydrogen-bromine redox flow battery cells with 1-ethylpyridin-1-ium bromide ([C2Py]Br) as BCA in a bromine electrolyte with a theoretical capacity of 179.6 A h L$^{-1}$ is investigated for the first time. The BCA leads to increased ohmic overvoltages. One cause of the ohmic drop can be attributed to [C2Py]$^{+}$ cation interaction with the perfluorosulfonic acid (PFSA) membrane, which results in a drop of its conductivity. The BCA also interacts with bromine in the cell, by forming a non-aqueous fused salt second phase which exhibits a ten times lower conductivity compared to the aqueous electrolyte. A steep rise in cell voltage at the beginning of the charge curve followed by a regeneration of the cell voltage is attributed to this effect. Electrolyte crossover leads to an accumulation of [C2Py]$^{+}$ in the electrolyte solution and intensifies both adverse processes. Under this condition only 30% of the theoretical electrolyte capacity of 179.6 A h L$^{-1}$ is available under long term cycle conditions. However, electrolyte capacity is high enough to compete with other flow battery technologies

Cycle behaviour of hydrogen bromine redox flow battery cells with bromine complexing agents

Bromine complexing agents (BCA) are used to improve the safety of aqueous bromine electrolytes versus bromine outgassing in bromine electrolytes. In this work, cycling performance of hydrogen-bromine redox flow battery cells with 1-ethylpyridin-1-ium bromide ([C2Py]Br) as BCA in a bromine electrolyte with a theoretical capacity of 179.6 A h L$^{-1}$ is investigated for the first time. The BCA leads to increased ohmic overvoltages. One cause of the ohmic drop can be attributed to [C2Py]$^{+}$ cation interaction with the perfluorosulfonic acid (PFSA) membrane, which results in a drop of its conductivity. The BCA also interacts with bromine in the cell, by forming a non-aqueous fused salt second phase which exhibits a ten times lower conductivity compared to the aqueous electrolyte. A steep rise in cell voltage at the beginning of the charge curve followed by a regeneration of the cell voltage is attributed to this effect. Electrolyte crossover leads to an accumulation of [C2Py]$^{+}$ in the electrolyte solution and intensifies both adverse processes. Under this condition only 30% of the theoretical electrolyte capacity of 179.6 A h L$^{-1}$ is available under long term cycle conditions. However, electrolyte capacity is high enough to compete with other flow battery technologies

Object Specific Trajectory Optimization for Industrial X-ray Computed Tomography

In industrial settings, X-ray computed tomography scans are a common tool for inspection of objects. Often the object can not be imaged using standard circular or helical trajectories because of constraints in space or time. Compared to medical applications the variance in size and materials is much larger. Adapting the acquisition trajectory to the object is beneficial and sometimes inevitable. There are currently no sophisticated methods for this adoption. Typically the operator places the object according to his best knowledge. We propose a detectability index based optimization algorithm which determines the scan trajectory on the basis of a CAD-model of the object. The detectability index is computed solely from simulated projections for multiple user defined features. By adapting the features the algorithm is adapted to different imaging tasks. Performance of simulated and measured data was qualitatively and quantitatively assessed. The results illustrate that our algorithm not only allows more accurate detection of features, but also delivers images with high overall quality in comparison to standard trajectory reconstructions. This work enables to reduce the number of projections and in consequence scan time by introducing an optimization algorithm to compose an object specific trajectory

Recent approaches in the development and enhancement of self-regulated learning

Bedingungen heutiger Schule und heutigen Studiums bringen eine erhebliche Zunahme des außerschulischen Lernens außerhalb von Präsenzphasen mit sich, was eine erhebliche Lernbelastung für Schüler und Studenten bedeutet. Für die Unterstützung und Förderung der Kompetenz zu selbstgesteuertem Lernen wurden in neuerer Zeit einige Programme entwickelt, die hier in ihren wesentlichsten Prinzipien knapp dargestellt und kritisch danach bewertet werden sollen, ob sie tatsächlich eine eigenständige Lernweggestaltung und Lernüberprüfung ermöglichen können. (DIPF/Orig.)Conditions and context of contemporary schooling and studying lead to a considerable increase in intensity and amount of learning beyond school or university. College and university students thus are confronted with operations beyond capacity. Some recent work has focussed on the development of remedial and supportive learning and schooling programs to foster and assist self-guided study. Some of these programs are sketched in their main principles. The programs are further evaluated for their factual assistance and impact on the planning, checking and control of learning by means of independent learner-guided self-regulation

Pressure-dependent hydrometra dimensions in hysteroscopy

Aim: To investigate the relation between intrauterine pressures and volumes for virtual-reality-based surgical training in hysteroscopy. Material and methods: Ten fresh extirpated uteri were insufflated by commercial hysteroscopy pump and imaged by computer tomography (CT) under intrauterine air pressure in distension-collapse cycles between 0, 20 (150mmHg), and 0kPa, performing a CT scan at every step at about 2.7kPa (20mmHg). Results: An initial threshold pressure to distend the cavity was avoided by introducing the insufflation tube up to the fundus. The filling and release phases of seven uteri that were completely distended showed the typical characteristics of a hysteresis curve which is expected from a viscoelastic, nonlinear, anisotropic soft tissue organ like the uterus. In three cases tightening the extirpated uterus especially at the lateral resection lines caused significant problems that inhibited registration of a complete distension-collapse cycle. Interpolated volumes for complete distended cavities and extrapolated for incomplete data sets, derived from the digitally reconstructed three-dimensional (3D) geometries, ranged from 0.6 to 11.4mL at 20kPa. These values highly correlate with the uterine volume (not insufflated) considering different biometric data of the uteri and patient data. Linear (R 2=0.66) and quadratic least-squares fits (R 2=0.74) were used to derive the formulas y=0.069x and y=0.00037x 2+0.036x, where x is the uterine volume in mL (not insufflated) and y is the cavity volume in mL at 20kPa intrauterine pressure. Conclusions: Our experimental hysteroscopical setup enabled us to reconstruct the changes in volumes of insufflated uteri under highly realistic conditions in 3D. The relation between intrauterine pressure and cavity volume in distension-collapse cycles describes a typical hysteresis curv

Systematic study of quaternary ammonium cations for bromine sequestering application in high energy density electrolytes for hydrogen bromine redox flow batteries

Bromine complexing agents (BCAs) are used to reduce the vapor pressure of bromine in the aqueous electrolytes of bromine flow batteries. BCAs bind hazardous, volatile bromine by forming a second, heavy liquid fused salt. The properties of BCAs in a strongly acidic bromine electrolyte are largely unexplored. A total of 38 different quaternary ammonium halides are investigated ex situ regarding their properties and applicability in bromine electrolytes as BCAs. The focus is on the development of safe and performant HBr/Br$_{2}$/H$_{2}$O electrolytes with a theoretical capacity of 180 Ah L$^{-1}$ for hydrogen bromine redox flow batteries (H$_{2}$/Br$_{2}$-RFB). Stable liquid fused salts, moderate bromine complexation, large conductivities and large redox potentials in the aqueous phase of the electrolytes are investigated in order to determine the most applicable BCA for this kind of electrolyte. A detailed study on the properties of BCA cations in these parameters is provided for the first time, as well as for electrolyte mixtures at different states of charge of the electrolyte. 1-ethylpyridin-1-ium bromide [C$_{2}$Py]Br is selected from 38 BCAs based on its properties as a BCA that should be focused on for application in electrolytes for H$_{2}$/Br$_{2}$-RFB in the future