bluuebunny/crossref_metadata_2025 huggingface dataset:
Moisture accumulation analyses over windowpane, based on onsite measurements in sleeping room
Authors: Ivanov Martin
Published: November 2020

The current paper presents moisture accumulation analyses over windowpane, based on onsite measurements in genuine sleeping room. During the measurements, the room was occupied with two adults and a baby, and the occupant’s behaviour was not additionally modified. The examination of the results represented the generic conditions for the windowpane condensation appearance, without taking into account the window assembly properties or the building construction. The studied windowpane has visually confirmed condensation in the lower left corner. This moisture accumulation is confirmed by the obtained measurement results near the windowpane, which clearly showed lower air temperature and higher relative humidity, compared with the rest of the occupied space. Thermal images also confirm this effect, and give better interpretation of the time periods, at which the surface temperature of the windowpane is lower than the dew point temperature in the affected zone. The analysed results offer important understanding of the interference of the different indoor parameters, related to the generic conditions for windowpane condensation appearance. These results may contribute the development of numerical model, capable to predict the heat losses and the moisture accumulation processes, in such affected areas from the building envelope.
Modelling and numerical simulation of the heat transfer and natural ventilation in storage halls
Authors: Penkova Nina , Krumov Kalin , Mladenov Boian , Stoyanov Yordan
Published: November 2020

An algorithm for modelling of the heat transfer in storage halls at different combinations of open doors and smoke vents is developed. The models allow numerical simulations of velocity, pressure and temperature fields in the halls in cases of transient and steady state conditions, taking into account the indoor buoyancy, heat sources, heat transfer through the building envelopes and outdoor wind pressures. The models are solved numerically via finite volume method in order to estimate the necessity of additional heating at a design stage of a courier logistic storage hall, situated in the temperate climate zone, at the hardest winter conditions of the region. Recommendations about the organization of the heating and the cargo input are done based on the analyses of the fluid flow and thermal fields at the modelled scenarios.
Heat transfer performance of R1234yf for convective boiling in horizontal micro-fin and smooth tubes
Authors: Phan Thanh Nhan , Tran Van Hung , Kaloyanov Nikola , Vassilev Momchil
Published: November 2020

This study analyses the performance of heat transfer process which occurs in the convective boiling of Hydro fluoro Olefin (HFO) refrigerant, R1234yf, in horizontal tube. Heat transfer and pressure drop of R1234yf are analyzed and computed at the same working conditions on the same size of outer diameter of tube do = 9.52 mm with difference of inner surface, one is a smooth surface and microfin for other. The flow pattern maps were built at 5°C saturation temperature with 8.62 kW/m2of heat flux, it is presented that flow pattern of helix flow occurs at very low mass flux and low quality, while at that condition on smooth tube the flow is still stratified wavy flow. The comparison of heat transfer performance between microfin and smooth tube would be evaluated on enhancement factorE, penalty factorPand efficiency indexI. With the mass flux on the rangeG= 111 -- 333 kg/m2s for 5°C boiling temperature, the results show that, average value ofEis 2.18; 1.45 ofPand 1.54 ofI. One more impressing thing is that, at the quality “x” larger than 0.8, the dryout phenomenon takes place on smooth tubes while microfin tubes do not have this phenomenon.
Investigation of the possibilities for energy economy in continuous dryers through reduction of the drying time
Authors: Penkova Nina , Mladenov Boian
Published: November 2020

The possibility for a reduction of the time duration of an industrial drying of ceramic bricks are analysed based on numerical simulation of the transient coupled mass transfer and mechanical processes in the material. The differences between the local mechanical stresses and strength in the dried bodies are computed and used as a criterion for this possibility. Ways for reorganization of the existing process parameters in the dryers to achieve the corrected drying kinetic curve are discussed. The expected effects on the efficiency of the drying installation are evaluated via material and thermal balance.
Efficiency evaluation of water production from the atmospheric air in Vietnam
Authors: Tran Van Hung , Phan Thanh Nhan , Kaloyanov Nikola , Vassilev Momchil
Published: November 2020

The analysis of extracting potable water from the humid ambient air has been done by using the model of vapor-compression refrigeration (VCR) system for the case study in Vietnam. The temperature and relative humidity of moist air in Danang province in Vietnam were recorded for a whole year. The typical day in each month of year with detailed values of temperature and relative humidity for 24 hours were presented and used to identify the production of water from the air. The results show that, the temperature at the outlet of air stream throughout evaporator of VCR system is about 13°C in which the energy consumption to produce 1 liter of water is lowest. Besides, the electricity consumption cost in Vietnam varies in a day with various tariffs: at the peak load, medium load and low load, depends on the time of the day. The production price for one liter of water is also considered and working plans are proposed for the system by the time of the day.
Long-Term Radiotoxicity Evaluation of PWR Spent Uranium and MOX Fuel and Highly Active Waste
Authors: Paunov Petar , Naydenov Ivaylo
Published: November 2020

One of the main concerns related to nuclear power production is the generation and accumulation of spent nuclear fuel. Currently most of the spent fuel is stored in interim storage facilities awaiting final disposal or reprocessing. The spent fuel is stored in isolation from the environment in protected facilities or specially designed containers. Nevertheless, spent fuel and highly active waste might get in the environment in case the protective barriers are compromised. In such a case, spent fuel may pose risk to the environment and human health. Those risks depend on the concentration of the given radionuclide and are measured by the value of potential danger. The potential danger is called also ’radiotoxicity’. The paper examines spent uranium and MOX fuels from a reference PWR, as well as the highly radioactive wastes of their reprocessing. The radiotoxicity of the four materials is examined and evaluated for a cooling time of 1000 years. The contribution of different radionuclides is assessed and the cases of reprocessing and no reprocessing of spent fuel have been compared.
Study of the thermodynamic efficiency of solid fuel preparation systems of a thermal power plant based on an exergy analysis of the operation of subsystems
Authors: Kamarova Saule , Abildinova Saule , Terziev Angel
Published: November 2020

Own energy consumption needs at combined heat and power plant depends on the type and installed capacity of the main and auxiliary equipment installed on-site, as well as the type of the fuel and combustion method used. The coal dust preparation system, in turn, is the most energy- intensive part of coal mining. Therefore, methods for improving the operation of the fuel path of a combined heat and power plant and the technology for producing coal dust are very relevant. The present study proposes a comprehensive methodology for determining the thermodynamic efficiency of solid fuel preparation systems at combined heat and power plant 2 (CHP-2) in the city of Temirtau of the Republic of Kazakhstan. Outdated equipment is operated at the CHP and there is virtually no automation of technological processes related with the solid fuel preparation system. The scientific novelty of the work is the theoretical study and analysis of the thermodynamic efficiency of an individual dust preparation system with an intermediate hopper when grinding coal. The thermal and thermodynamic calculations based on the determination of exergy efficiency for individual units of the dust system and the system as a whole allow to propose means to increase the efficiency of the coal industry and give recommendations to reduce energy costs for the plant’s own needs. As a recommendation to reduce energy costs for the preparation of coal dust, the installation of a crushing press with a studded surface is proposed, which allows grinding large pieces of coal to optimal sizes (25 mm) in the absence of preliminary crushing of the material on-site. An automation scheme for the entire dust preparation system is proposed, including automation of the operation of the intermediate coal dust bin. Automatic control of the supply of coal dust from the intermediate hopper allows to determine the exact fuel consumption of the steam boiler, which were not permissible under the previous conditions of the dust system due to the use of a semi-mechanical method of regulating the supply of coal dust to the boiler.
Renewable energy and green construction in the Arctic
Authors: Gassiy Violetta , Stoikov Vasiliy
Published: November 2020

In the paper the issues on the renewable energy and green construction in the Arctic are considered. The authors analyze the premises of the green construction in the Northern territories. They propose that the Arctic could be seen as the innovative platform to test the newest technologies for construction and energy generation. The factors impacted on the industrial development are also researched. The authors assess the modern trends of the Arctic construction sphere using the data on housing development, energy consumption etc. They justify that to increase the production of thermal energy in the northern regions of Russia, the green technologies development is the most profitable and long-term. Moreover, the definition of “green technologies” includes not only wooden construction and solar panels, but also many other quite affordable technologies. In the Conclusions the results of the research are performed, including the recommendations on the green construction development considering the specificity of the Arctic territories.
Renewable energy and green market development in Russia
Authors: Gassiy Violetta , Stoikov Vasiliy
Published: November 2020

The paper discusses the possibilities of green energy in improving the economic growth of regions, the development of the green market and its importance in implementing environmental protection policy. The author considers the premises for the formation of a market of renewable energy sources in developed countries, studying world trends, as well as the conditions and factors affecting the development of the ecological market of green goods and services in modern Russia. The paper analyzes legislative initiatives to develop an alternative energy market, taking into account Russia’s accession to the Paris climate agreement. The author gives examples of regional experience in Russia that are already implementing projects for the installation of alternative energy generators, wind and solar. The conditions and factors for the energy capacities development based on renewable sources in the Arctic territories are also considered. The author concludes that the development of renewable energy sources must be considered in the line of the energy strategy of Russia, as well as with issues of digitalization of the industry, microgeneration, the introduction of energy storage systems.
A Study of a Darrieus Vertical Axis Wind Turbine with a guiding nozzle
Authors: Obretenov Valentin , Tliev Rossen
Published: November 2020

This paper presents the results from an experimental study of a Vertical Axis Wind turbine model with a guiding nozzle. The geometry of the nozzle is synthesized by an original methodology. The performance characteristics of the turbine are investigated when changing the number of the blades and their pitch angle. The obtained results allow us to generate generalized characteristics that can be used in the design of new turbines of this type. The results of the pilot studies showing higher efficiency than the classical Darrieus wind turbines (up to 50 % which is close to the Betz limit).
Cavitation treatment of water from a wastewater treatment plant
Authors: Stoeva Donka , Simitchiev Apostol , Hristov Hristo
Published: November 2020

Hydrodynamic cavitation damages the apparatus by intensive cavitational erosion of the elements in a hydro system. Being acquainted with the mechanisms of effect, hydrodynamic cavitation can be used to intensify technological processes in different industrial areas. The aim of the present work is to investigate the possibilities using hydrodynamic cavitation for wastewater treatment from an urban treatment plant. To intensify the purifying process series of trials, at different levels of intensity of the electrical field in the zone of cavitation, were performed. Additionally presented, the electrical field assists in forcing the process of silver ions separation with the purpose of microbiological purification of the flowing water. Here we present the results of experimental studies conducted at various times and electrical fields intensity. These trials substantiate the idea of the microbiological purification of wastewaters via hydrodynamic cavitation and represent a huge range of opportunities for applying this method in various industrial fields. The basic criterion that supports our statement is the enormous drop of the microbe number by increasing the cavitation treatment time.
A Study on the Effects of Technical Parameters on the Tensile Strength of Bamboo Plywood
Authors: Antonov Svetlin , Nam Nguyen Thanh , Hy Tran Trong , Dien Le Khanh
Published: November 2020

The application of bamboo by-products such as bamboo branches, chips to recycle and produce pressed bamboo pulp is an urgent task in Vietnam. It perfectly replaces natural wood with artificial wood embryos from bamboo powder, which has both economic benefits of reserving the source of raw materials, environmental protection The paper presents a study on the influence of technological parameters on the tensile strength of pressed bamboo plastic fiber that is a new product of a project of our laboratory.
Verification of the Fanger Model in Real Conditions
Authors: Krawczyk Natalia , Kapjor Andrej , Orman Łukasz J.
Published: November 2020

This study presents the issue of thermal comfort based on the Fanger model. The research was conducted in 5 rooms in the autumn-winter period. The research consisted of measurement of thermal environment parameters, air temperature and flow rate, relative air humidity, globe temperature sensor and light intensity. During the research, the students filled in questionnaires concerning thermal sensation. This allowed them to express their assessment of thermal comfort (predicted mean vote PMV and predicted percentage of dissatisfied PPD), as well as their preferences concerning the prevailing room conditions. Differences between the actual average predicted rating index and the Fanger model were shown. It can be noted that Fanger’s model does not reflect the results of the respondents.
Blowing Steam into the Boundary Layer on the Outer Wall of the Axial Exhaust Hood
Authors: Tupý David , Sláma Václav
Published: November 2020

The paper is devoted to experimental verification of flow on the steam turbine axial exhaust hood model. The main goal of the submitted paper is to evaluate the influence of additional air blowing into the boundary layer in the axial exhaust hood on the change of the pressure recovery coefficient. The experimental model was supplemented with a blowing track and fitted with a centric orifice for mass flow measurement. Several variants were measured with various types of inner struts and supports inside the hood for two values of Mach number at the diffuser inlet.
CAA Approaches for Duct Elements of HVAC Systems
Authors: Drabek Pavel , Zalesak Martin
Published: November 2020

In recent years there has been a significant increase in computing performance. This has allowed companies to make more use of numerical simulation methods during the development phase, even for areas that until recently were almost unfeasible. This article presents the fundamental aspects related to Computational Aero-Acoustics for internal flow with a focus on HVAC elements. The aim was to answer questions about the computational mesh, computational models and boundary conditions.
Flow Simulation as a Support to Predict Shape of Plasma Beam Affected by the Nozzle Geometry
Authors: Málek Miloslav , Mičian Miloš , Sládek Augustín
Published: November 2020

This paper deals with flow simulation of plasma beam shape affected by the different nozzle geometry. The flow simulations for different nozzles geometry were made in simulation software Ansys-Fluent. The evaluation of flow simulations was based on comparing shapes of the flow media out from the modified nozzle orifice against reference nozzle. There were investigated 8 different modification of nozzle orifice. Modified nozzle n. 7 (in the shape of a Laval nozzle) has achieved significant improvement from all simulated. There were observed 3 cores of plasma beam, which could help blow dross out from cutting gap. Investigated results serve for further research.
Effect of Multiple Liquid Inlets on Mass Transfer in Rotating Packed Beds
Authors: Elcner Jakub , Jicha Miroslav
Published: November 2020

This study deals with optimalization of rotating packed bed design using computational fluid dynamics approach. Comparison of three variants of liquid distributor were performed on 2D geometry. Turbulence was modelled using unsteady RANS approach and volume of fluid technique were used to simulate gas-liquid interphase. Results were compared on basis of liquid holdup evaluation.
Improvement of the Combustion Chamber
Authors: Novosád Jan , Peukert Pavel , Havrda Marcel
Published: November 2020

The subject of this work is the analysis of an independent heater combustion chamber. The main goals are the analysis of the current state and modification of the combustion chamber design, while the CFD methods are applied. The standard methodology considering the model and grid preparation and the ANSYS Fluent solver setup were provided to obtain the velocity, thermal and species concentration fields as results. These results were used for the analysis of the flame stability as well as the heat load of the individual component of the combustion chamber. The initial results leads to the identification of areas for possible improvement due to the uneven thermal fields and high thermal stress. Then, several modifications were designed and tested. Finally, the results for modified design were analysed to evaluate the variant suitable for future experimental testing.
Determination of the Local Pressure Loss Coefficient Experimentally and Using CFD Methods
Authors: Kubas Šimon , Kapjor Andrej , Vantúch Martin , Pafčuga Marián
Published: November 2020

When choosing silencers in air conditioning, it is necessary to pay attention not only to the acoustic attenuation, but also to the pressure loss of the silencer. If the pressure loss of the damper is too high, noise will occur directly in the damper. The pressure losses of the silencers are determined mainly experimentally. Based on the performed measurement, a CFD model of the selected silencer was constructed, where the influence of various parameters on the value of the pressure loss of the selected silencer was investigated.
Analysis of Unsteady Behaviour of Natural Circulation Helium Loop
Authors: Vach Matej , Knížat Branislav , Mlkvik Marek , Olšiak Róbert , Urban František , Ridzoň František , Mlynár Peter
Published: November 2020

This paper deals with the one-dimensional unsteady fluid flow model of the natural circulation loop. The presented model represents the experimental facility Helium Loop STU which is the physical model of an emergency coolant system of a nuclear reactor. The governing equations are solved according both Euler and Lagrange approaches on two parallel computational grids. Linearization of equations and semi-implicit discretization scheme are used to enhance the algorithm effectiveness. The simulation results were compared to experimental data. The model can be considered as high-accurate in comparison with experimental data (relative error 1.14÷1.15 % at specified time interval).
Efficiency of the RES Hybrid Microinstallations Working in Energy Clusters
Authors: Sowa Sławomir
Published: November 2020

The energy sector is constantly changing. Electromobility, improvement of energy efficiency, smart cities these are just some of the challenges that the present power industry is facing. The main goal for the power industry is to ensure the energy security of its customers, to develop low-community technologies which are mainly based on renewable energy sources and local raw materials. The transition from a centralized energy sector based mainly on conventional power plants to a distributed energy sector requires constant control and management of the generation and demand for energy. One of the solution existing since 2016 are energy clusters. The concept of their functioning is based on the civil-law agreement of locally operating entities that produce, sell, store and consume electricity, heat and cold. The main purpose of introducing energy clusters is the development of distributed energy. Energy clusters ensure the improvement of local energy security with relatively low outlays and low environmental impact. Technological development and installations based on renewable energy sources make energy clusters a beneficial and cost-effective solution for local energy sector. The article presents the idea of energy clusters functioning, and describes the current status of development. It also includes the hybrid systems characteristics of RES systems as an effective source of energy. The conclusion includes the legitimacy of the energy cluster development based on RES installations.
Dynamics of the Tip Vortices in the Wake Behind a Circular Cylinder of Finite Length
Authors: Uruba Václav , Procházka Pavel
Published: November 2020

The dynamics of the tip vortices in the wake behind a wall-mounted finite-length circular cylinder of the aspect ratio 2 was studied experimentally using time resolved stereo PIV technique. The cylinder was mounted normal to a ground plane and it was subjected to a cross-flow with thin boundary layer developed on the wall, the Reynolds number based on inflow velocity and cylinder diameter was 9.7 thousands. The dynamics of tip vortices were analysed using the POD method applied to the plane perpendicular to the flow close to the cylinder. Besides the decaying power spectrum, slower that the Kolmogorov-type one, the two distinct frequencies were detected on Strouhal numbers 0.09 and 0.15. These frequencies could be linked to the vortical structures dynamics in the wake. The frequency Sh = 0.15 corresponds to predominantly spanwise vortices dynamics with anti-symmetrical patterns with respect to the cylinder axis, while the frequency Sh = 0.09 corresponds to mainly streamwise vortical structures dynamics with symmetrical patterns respectively. Thus, the von Kármán vortex street was detected on Strouhal frequency 0.15.
De quoi l’inclusion est-elle le nom ? L’imaginaire des enseignants spécialisés en formation
Authors: Ployé Alexandre
Published: November 2020

Cet article se propose d’analyser les résultats d’un moment de recherche-formation vécu par l’auteur avec une centaine d’enseignants spécialisés stagiaires en formation à qui il est demandé de préparer puis d’exposer en groupe un projet pour une école inclusive idéale. Cette demande s’inscrit dans une suite de cours qui aura sensibilisé les stagiaires au tournant inclusif que connaissent les systèmes éducatifs depuis les années 2000. Le matériau recueilli est analysé dans une perspective clinique d’orientation psychanalytique en sciences de l’éducation et de la formation. Il s’agit ici de comprendre quel imaginaire, à la fois subjectif et social, dans les groupes de formation s’articule à la notion d’inclusion scolaire et comment cet imaginaire contribue à remanier l’identité professionnelle des enseignants spécialisés en formation. On retiendra notamment que ces derniers fantasment des « institutions pleines », comblantes, à rebours des prescriptions officielles, dans une logique psychique de défense contre l’angoisse liée à la relation éducative.
High-intensity Activity in European vs. National Rugby Union Games in the best 2014–2015 Team
Authors: Fornasier-Santos Charly , Millet Gregoire P , Stridgeon Paul , Girard Olivier , Brocherie Franck , Nottin Stéphane
Published: November 2020

The purpose of this study is to evaluate the influence of competition level on running patterns for five playing position in the most successful 2014–2015 European rugby union team. Seventeen French rugby union championship and seven European rugby Champions Cup games were analysed. Global positioning system (sampling: 10 Hz) were used to determine high-speed movements, high-intensity accelerations, repeated high-intensity efforts and high-intensity micro-movements characteristics for five positional groups. During European Champions Cup games, front row forwards performed a higher number of repeated high-intensity efforts compared to National championship games (5.8±1.6 vs. 3.6±2.3; +61.1%), and back row forwards travelled greater distance both at high-speed movements (3.4±1.8 vs. 2.4±0.9 m·min-1; +41.7%) and after high-intensity accelerations (78.2±14.0 vs. 68.1 ±13.4 m; +14.8%). In backs, scrum halves carried out more high-intensity accelerations (24.7±3.1 vs. 14.8±5.0; +66.3%) whereas outside backs completed a higher number of high-speed movements (62.7±25.4 vs. 48.3±17.0; +29.8%) and repeated high-intensity efforts (13.5±4.6 vs. 9.7±4.9;  +39.2%). These results highlighted that the competition level affected the high-intensity activity differently among the five playing positions. Consequently, training programs in elite rugby should be tailored taking into account both the level of competition and the high-intensity running pattern of each playing position.
Oberflächliche Venenthrombose
Authors: Barner Saskia , Massoudy Madina , Stücker Markus
Published: November 2020

Die oberflächliche Venenthrombose wird zunehmend als ernstes Krankheitsbild und nicht nur als eine Befindlichkeitsstörung aufgefasst. Zu unterscheiden sind Oberflächenthrombosen in Varizen und in nichtvarikösen Gefäßen. Zur Diagnostik einer Oberflächenthrombose gehört immer eine sonografische Untersuchung zum Ausschluss einer tiefen Thrombose. Während Thromben in Seitenastvenen auch ohne Antikoagulation behandelt werden können, gelten Thromben mit einer Länge von über 5 cm in Stammvenen oder größeren Seitenästen als Indikation für eine Antikoagulation mit Fondaparinux in Prophylaxe-Dosierung über einen ausreichend langen Zeitraum von 30–45 Tagen. Reichen die Oberflächenthrombosen näher als 3 cm an eine Junktion der Stammvene heran, ist eine Behandlung wie bei einer tiefen Beinvenenthrombose angezeigt. Bei ätiologisch unklaren Oberflächenthrombosen sollte eine maligne Grunderkrankung ausgeschlossen werden.
Scrolling of the Donor Cornea in Dependence of Temperature and Osmolarity for Descemet Membrane Endothelial Keratoplasty
Authors: Gruber Markus , Reinhard Thomas , Wacker Katrin , Maier Philip Christian
Published: November 2020

Background After preparation of a graft for Descemet membrane endothelial keratoplasty (DMEK), the diameter of the graftʼs scroll varies significantly. In particular, narrow scrolls
may complicate DMEK surgery. In this study we investigated how temperature, osmolarity, and deswelling of the donor tissue influence scrolling diameter.

Material and Methods In this study we examined donor corneas that could not be used for transplantation. The diameter of the DMEK donor scrolls was measured after graft preparation
by reflected light microscopy under different conditions: (1) The diameter of the roll was measured in Ringerʼs solution at temperatures of 5 °C, 24 °C and 35 °C. (2) To study the effect of
different culture conditions we used 6% dextran-containing medium for 10 min, 20 min, 16 h and 24 h, and hyper- and hypoosmolar fluids (5% NaCl or aqua dest) for 5 min each.

Results The median donors age was 62 years. The median endothelial cell density of the donor corneas was 1679 cells/mm2. The median diameter of the DMEK scroll was 1.35 mm
in Ringerʼs solution at 24 °C (IQR, 1.04 – 1.89). In Ringerʼs solution at different temperatures, the scrolling diameter changed between 0.02 mm and 0.29 mm. The change in osmolarity
resulted in a difference of 0.02 mm to 0.46 mm. Deswelling with dextran resulted in a change of scrolling diameter between 0.02 mm and 0.09 mm.

Summary In this experimental case series, the diameter of the DMEK scroll did not change due to changes of temperature, osmolarity or deswelling. Influencing the graftʼs scroll to
standardize and simplify the DMEK surgery remains an interesting goal for future studies.
Per-oral endoscopic myotomy (POEM) training and skills evaluation tool: a pilot study
Authors: Schlachterman Alexander , Aziz Ahmed , Alajlan Bader , Han Samuel , Machicado Jorge , Wagh Mihir S.
Published: November 2020

Background and study aims Hands-on training for per-oral endoscopic myotomy (POEM) in the United States is limited and without a structured curriculum or assessment tool. Training to competency in POEM is critical and POEM trainees must acquire multiple cognitive and technical skills to achieve proficiency. The aim of this study was to develop a POEM training and skills evaluation tool.

Patients and methods The training protocol included initial explant porcine models followed by live human cases, proctored by a single endoscopist experienced in POEM who prospectively graded trainees for each step (“skill”) of the procedure on a 5-point scale. Procedural skills were divided into cognitive and technical skills. Acceptable passing level was considered a score ≥ 4 for each skill.

Results Three trainees completed a total of 18 cases (8 cases on animal explant models and 10 human cases). Overall, cognitive skills were acquired early in training with scores of ≥ 4 achieved by ≤ 3 cases. Technical skills required more cases and direction with scores ≥ 4 in technical skills achieved by three porcine and eight human cases. Entry of the endoscope into the submucosal space and submucosal tunneling were the most challenging steps followed by myotomy.

Conclusion This pilot study introduces a POEM training and skills evaluation tool for training to competency. Submucosal entry, tunneling, and myotomy were the most challenging to learn while cognitive skills were learned early in training. Evaluation of more trainees at multiple sites will be necessary to further validate the utility of this tool.
Die neuen WHO-Empfehlungen für schnelle Diagnostik und Therapie resistenter Tuberkulose in Deutschland, Österreich und der Schweiz
Authors: Otto-Knapp R. , Knappik M. , Häcker B. , Starzacher K. , Bauer T. , Lange C. , Maurer F. P. , Schaberg T. , Günther G.
Published: November 2020

Die erfreulicherweise zunehmende Evidenz hat in den letzten Jahren mehrfache Änderungen der internationalen Empfehlungen für die Diagnostik und Therapie der resistenten Tuberkulose notwendig gemacht. In diesem Jahr hat die WHO umfassende Empfehlungen veröffentlicht, die die Entwicklungen der letzten Jahre berücksichtigen. Die aktuelle deutsche Tuberkuloseleitlinie erschien im Jahr 2017 und weicht in einigen Bereichen von diesen Empfehlungen ab. Hier werden die Neuerungen der WHO-Empfehlungen von 2020 für schnelle Diagnostik und die Therapie resistenter Tuberkulose zusammengefasst und relevante Abweichungen für Deutschland, Österreich und die Schweiz kommentiert. Eine Neubewertung der Literatur findet derzeit im Rahmen der Aktualisierung der deutschsprachigen AWMF-2k-Leitlinie statt.
Acute obstructive suppurative pancreatic ductitis in pancreatic malignancies
Authors: Shimizuguchi Ryoko , Kikuyama Masataka , Kamisawa Terumi , Kuruma Sawako , Chiba Kazuro
Published: November 2020

Background and study aims Acute obstructive suppurative pancreatic ductitis (AOSPD) is a suppurative pancreatic duct infection with main pancreatic duct (MPD) or accessory pancreatic duct obstruction in the absence of a pancreatic pseudocyst or necrosis, which is experienced usually in chronic pancreatitis. The diagnosis is confirmed by the finding of pancreatic duct obstruction on endoscopic retrograde cholangiopancreatography (ERCP) with evidence of infection, such as a positive pancreatic juice culture or drainage of purulent pancreatic juice.

Patients and methods We studied five patients with pancreatic ductal adenocarcinoma (PDAC) and one with chronic myelogenous leukemia (CML), who suffered from AOSPD.

Results Of the 281 PDAC and 39 CML patients who we treated in the past 2 years in our hospital, five with PDAC (1.8 %) and one with CML (2.6 %) experienced AOSPD. Each patient had fever, abdominal pain, and increased blood C-reactive protein. Pancreatography found that each patient had a MPD stricture and an upstream dilatation. Four had a disruption of the MPD in the upper stream of the stricture. Nasopancreatic drainage was successfully performed in all patients. Pancreatic juice culture was positive for Klebsiella pneumonia, Enterobacter agerogenes, or Enterococcus cloacae in four patients.

Conclusion AOSPD should be considered in pancreatic malignancy with fever and abdominal pain. Prompt diagnosis of AOSPD could avoid shortening of survival of patients with an already poor prognosis by infection.
Safety and adequacy of endoscopic ultrasound-guided random liver biopsy in comparison with transjugular and percutaneous approaches
Authors: Bhogal Neil , Lamb Bernadette , Arbeiter Benjamin , Malik Sarah , Sayles Harlan , Lazenby Audrey J. , Chandan Saurabh , Dhaliwal Amaninder , Singh Shailender , Bhat Ishfaq
Published: November 2020

Background and study aims Endoscopic ultrasound-guided liver biopsy (EUS-LB) is an accepted technique for tissue acquisition. Traditionally, random LB has been performed with percutaneous (PC-LB) and transjugular (TJ-LB) approaches. The purpose of this study was to compare the safety profile and efficacy of EUS-LB, PC-LB, and TJ-LB.

Patients and methods A retrospective analysis was performed at a tertiary academic medical center. Inclusion criteria for analysis were all adult patients who underwent EUS-LB since inception and TJ-LB/PC-LB over a 3-year span (June 2016 to June 2019). The primary outcome assessed was any adverse events. Secondary outcomes included technical success resulting in tissue acquisition and diagnostic adequacy of the sample for histologic analysis.

Results A total of 513 patients were included for analysis. There were 135 EUS-LB, 287 PC-LB, and 91 TJ-LB. The most common indication for LB was abnormal liver function tests. For the primary outcome, the rate of adverse events was low with five reported (< 1 %). There were two in the EUS-LB group, two in the PC-LB group, and one in TJ-LB group, and this difference was not statistically significant (P = 0.585). The technical success rate was 100 % in each group. The rate of diagnostic adequacy was 100 % in TJ-LB group and 99 % in both EUS-LB and PC-LB groups. This difference was not statistically significant (P = 1.000). The most common histologic finding was non-specific changes (33.7 %) followed by non-alcoholic steatohepatitis (15.60 %).

Conclusion In comparison with PC-LB and TJ-LB, EUS-LB has comparable safety profile, technical success rate, and diagnostic adequacy. EUS-LB should be considered as an option for random liver biopsy.
The Role of Glucocorticoids in the Management of COVID-19
Authors: Alexaki Vasileia Ismini , Henneicke Holger
Published: November 2020

Coronavirus disease 2019 (COVID-19), caused by an infection with the novel coronavirus SARS-CoV-2, has resulted in a global pandemic and poses an emergency to public health systems worldwide. COVID-19 is highly infectious and is characterized by an acute respiratory illness that varies from mild flu-like symptoms to the life-threatening acute respiratory distress syndrome (ARDS). As such, there is an urgent need for the development of new therapeutic strategies, which combat the high mortality in severely ill COVID-19 patients. Glucocorticoids are a frontline treatment for a diverse range of inflammatory diseases. Due to their immunosuppressive functions, the use of glucocorticoids in the treatment of COVID-19 patients was initially regarded with caution. However, recent studies concluded that the initiation of systemic glucocorticoids in patients suffering from severe and critical COVID-19 is associated with lower mortality. Herein we review the anti-inflammatory effects of glucocorticoids and discuss emerging issues in their clinical use in the context of COVID-19.
Gastroesophageal Reflux Disease and Need for Antireflux Surgery in Children with Cystic Fibrosis: A Systematic Review on Incidence, Surgical Complications, and Postoperative Outcomes
Authors: Ng Jessica , Friedmacher Florian , Pao Caroline , Charlesworth Paul
Published: November 2020

Introduction Gastroesophageal reflux disease (GERD) is associated with accelerated decline in lung health in children with cystic fibrosis (CF). Thus, antireflux surgery (ARS) is offered to a selected CF cohort with refractory GERD, but outcomes remain poorly investigated. This study aimed to determine the incidence of GERD in children with CF and to evaluate complications and outcomes of ARS.

Materials and Methods A systematic literature-based search was conducted using various online databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The number of GERD cases in pediatric CF cohorts who underwent diagnostic investigation(s) was recorded. Data on postoperative complications and outcomes (including symptoms, lung function, and nutritional status) following ARS were analyzed.

Results Ten articles (n = 289 patients) met the defined inclusion criteria (51% male; age range, 0.5 month–36 years). The overall incidence of GERD was 46% (range, 19–81%), derived from seven studies (n = 212 patients). Four publications (n = 82 patients) reported on ARS due to uncontrolled GERD. All ARSs were Nissen fundoplication (majority with gastrostomy placement). Major postoperative complications occurred in 15 (18%) patients, two required redo-ARS. Median follow-up time was 2 years (range, 3 months–6 years); 59% showed symptom improvement, and pulmonary exacerbations and decline in lung function were reduced. Nutritional status mainly improved in milder CF cases. There were no deaths related to ARS.

Conclusion Approximately half of pediatric CF patients have GERD. Published data for children with CF are limited and heterogeneous in terms of GERD diagnosis and outcomes following ARS. However, ARS has shown to slow the deterioration of lung function in CF.
Comparison of DNA Methylation Profiles of Hemostatic Genes between Liver Tissue and Peripheral Blood within Individuals
Authors: Angerfors Annelie , Olsson Lindvall Martina , Andersson Björn , Nilsson Staffan , Davila Lopez Marcela , Hansson Lena , Stanne Tara M. , Jern Christina
Published: November 2020

DNA methylation has become increasingly recognized in the etiology of complex diseases, including thrombotic disorders. Blood is often collected in epidemiological studies for genotyping and has recently also been used to examine DNA methylation in epigenome-wide association studies. DNA methylation patterns are often tissue-specific, thus, peripheral blood may not accurately reflect the methylation pattern in the tissue of relevance. Here, we collected paired liver and blood samples concurrently from 27 individuals undergoing liver surgery. We performed targeted bisulfite sequencing for a set of 35 hemostatic genes primarily expressed in liver to analyze DNA methylation levels of >10,000 cytosine-phosphate-guanine (CpG) dinucleotides. We evaluated whether DNA methylation in blood could serve as a proxy for DNA methylation in liver at individual CpGs. Approximately 30% of CpGs were nonvariable and were predominantly hypo- (<25%) or hypermethylated (>70%) in both tissues. While blood can serve as a proxy for liver at these CpGs, the low variability renders these unlikely to explain phenotypic differences. We therefore focused on CpG sites with variable methylation levels in liver. The level of blood–liver tissue correlation varied widely across these variable CpGs; moderate correlations (0.5 ≤ r < 0.75) were detected for 6% and strong correlations (r ≥ 0.75) for a further 4%. Our findings indicate that it is essential to study the concordance of DNA methylation between blood and liver at individual CpGs. This paired blood–liver dataset is intended as a resource to aid interpretation of blood-based DNA methylation results.
Computed Tomographic Diagnosis of Traumatic Atlanto-occipital Rotatory Luxation and Successful Closed Reduction in a Dog
Authors: Lye Gordon , Mathis Karl , Hill Sarah , Cattin Ryan , Hartman Angela
Published: November 2020

A 12-year-old, female spayed crossbred dog was presented for traumatic injuries sustained after being hit by a car. The dog was non-ambulatory with a right-sided head tilt on presentation, neurological deficits and signs of external trauma centred on the head. A trauma computed tomography was performed which revealed an atlanto-occipital luxation with narrowing of the vertebral canal. This was treated successfully via closed reduction and confirmed with a repeat computed tomography scan. The dog recovered well following the atlanto-occipital luxation reduction, and was ambulatory the day after the reduction, and neurological signs resolved within 2 days.
A wearing energy model
Authors: Li D. Y. , Pan Hongbo
Published: November 2020

The classic sliding wear model, represented by Archard's equation, has long been used to estimate the service life of equipment and guide selection and modification of tribo-materials. However, the model was developed based on the asperity contact geometry without directly dealing with the wearing energy, rendering it unable to precisely describe wear under some conditions, e.g., it fails to predict wear of strain-hardened materials, which has never been clarified. In this study, incorporating with the plastic deformation–electron work function relationship, we reexamined and modified the classic model by taking account of the deformation energy consumption during wear. The modified model, or termed a wearing-energy model, is verified with relevant experimental observations.
Influence of chemical treatment on strain and charge doping in vertically stacked monolayer–bilayer MoS2
Authors: Kim Hanul , Lee Taegeon , Ko Hayoung , Kim Soo Min , Rho Heesuk
Published: November 2020

We report simultaneous Raman scattering and photoluminescence (PL) mapping results to study the strain and doping effects of chemical treatment with bis(trifluoromethane) sulfonimide (TFSI) on the optical phonon, exciton, and trion characteristics of a vertically stacked monolayer–bilayer (1L–2L) MoS2 structure. Correlation analysis between the E′ and A1′ phonon energies revealed that tensile strain developed in the TFSI-treated MoS2 mainly by the filling of sulfur vacancies: 0.13% and 0.10% for 1L and 2L MoS2, respectively. In addition, TFSI-induced changes in the electron densities evaluated from the Raman correlation analysis were estimated to be −0.38×1013 cm−2 and −1.21×1013 cm−2 for 1L and 2L MoS2, respectively. The larger p-doping effect in 2L than in 1L MoS2 was attributed to a relatively higher defect density in the 2L region of the pristine MoS2, followed by a subsequent healing of the defects via chemical doping. The TFSI-induced change in electron density estimated from the PL result was in excellent agreement with the Raman correlation analysis. Furthermore, the Raman mapping and PL histogram analyses showed that structural defects in MoS2 could be effectively healed by chemical treatment.
Efficient local energy evaluation for multi-Slater wave functions in orbital space quantum Monte Carlo
Authors: Mahajan Ankit , Sharma Sandeep
Published: November 2020

We present an algorithm for calculating the local energy of a multi-Slater wave function in orbital space quantum Monte Carlo (QMC). Recent developments in selected configuration interaction methods have led to increased interest in using multi-Slater trial wave functions in various QMC methods. For an ab initio Hamiltonian, our algorithm has a cost scaling of O(n5 + nc), as opposed to the O(n4nc) scaling of existing orbital space algorithms, where n is the system size and nc is the number of configurations in the wave function. We present our method using variational Monte Carlo calculations with the Jastrow multi-Slater wave function, although the formalism should be applicable for auxiliary field QMC. We apply it to polyacetylene and demonstrate the possibility of using a much larger number of configurations than possible using existing methods.
A computational study on osmotic chemotaxis of a reactive Janusbot
Authors: Mitra Shirsendu , Pasupalak Anshuman , Majumdar Saptarshi , Bandyopadhyay Dipankar
Published: November 2020

We explore the chemotaxis of an elliptical double-faced Janus motor (Janusbot) stimulated by a second-order chemical reaction on the surfaces, aA + bB → cC + dD, inside a microfluidic channel. The self-propulsions are modeled considering the full descriptions of hydrodynamic governing equations coupled with reaction–diffusion equations and fluid–structure interaction. The simulations, employing a finite element framework, uncover that the differential rate kinetics of the reactions on the dissimilar faces of the Janusbot help in building up enough osmotic pressure gradient for the motion as a result of non-uniform spatiotemporal variations in the concentrations of the reactants and products around the particle. The simulations uncover that the mass diffusivities of the reactants and products along with the rates of forward and backward reactions play crucial roles in determining the speed and direction of the propulsions. Importantly, we observe that the motor can move even when there is no difference in the total stoichiometry of the reactants and products, (a + b) = (c + d). In such a scenario, while the reaction triggers the motion, the difference in net-diffusivities of the reactants and products develops adequate osmotic thrust for the propulsion. In contrast, for the situations with a + b ≠ c + d, the particle can exhibit propulsion even without any difference in net-diffusivities of the reactants and products. The direction and speed of the motion are dependent on difference in mass diffusivities and reaction rate constants at different surfaces.
Vorticity generation by finite Larmor radius effects from heat source and sink
Authors: Kim S. S. , Jhang Hogun
Published: November 2020

We investigate the finite Larmor radius (FLR) effects that are associated with an external heat source or a sink in the full-f formulation of plasma dynamics. Specifically, we show that a gyrocenter or an additional vorticity source due to the FLR effect should be replenished in full-f turbulence simulations. A quantitative energetics analysis in particle phase space demonstrates that an additional vorticity source is required to satisfy the total energy conservation. A physics picture is presented to elucidate the mechanism of the vorticity source generation from the FLR effects of a heat source or a sink, which reproduces the main result obtained from the quantitative analysis. The additional vorticity source is expected to considerably enhance the generation of the radial electric field and subsequent E×B flow shear in the off-axis heating case.