bluuebunny/crossref_metadata_2025 huggingface dataset:
The ways to increase reliability of work of powerful electrical machines in autonomous electric networks
Authors: Boguslawsky Ilya , Zaboin Valery
Published: December 2018

The influence of the harmonic composition of the stator current on the permissible power of an electric machine during its operation in an autonomous nonlinear network is considered. A generalizing equation is proposed for calculating this power, taking into account an increase in the electric losses in the stator winding and losses in the steel of the machine. The analysis of the causes of voltage drop at the terminals of an autonomous generator is made and practical recommendations for its reduction are given for an unexpected change in the load of the generator.

The main purpose of investigation is to obtain a generalized expression is derived for calculating the permissible that makes to estimate a reduction of the nominal power of power of alternating current machine when operating in nonlinear networks in condition of knowing harmonics of the stator current. It is usefully for newly created generators and can suppose a changing the operational requirements by the standards for the to the value of transient deviation of the voltage when the load changes suddenly.
Experimental moment resistance of rectangular hollow section T joints
Authors: Garifullin Marsel
Published: December 2018

Resistance is the main property of tubular joints. The determination of the joint resistance from the experimental load-deformation curve always represents a challenging task. Currently there are two main methods to find the experimental resistance, which are called plastic and ultimate resistance. However, there is no single opinion on which one should be commonly used. Based on the experimental results, this paper directly compares the two existed approaches. The study is restricted to welded square hollow section T joints under in-plane bending moment. The paper considers only the joints with β < 0.85, i.e. when the behaviour of the joint is governed by chord face failure. The results show that plastic resistance leads to more conservative results than ultimate resistance, providing thus safer results. However, attention should be also paid to the difference between the labour intensity of the presented methods.
Analysis of marking criteria for mesh adaptation in Cosserat elasticity
Authors: Churilova Maria
Published: December 2018

The article is devoted to comparison of finite element marking criteria for adaptive mesh refinement while solving plane Cosserat elasticity problems. The goal is to compare the resulting adaptive meshes obtained with different marking strategies. Mesh refinement and error control is done using the functional type a posteriori error majorant. Implemented algorithms use the zero-order Raviart-Thomas approximation on triangular meshes. Four widely used marking criteria are utilized for mesh adaptation. The comparative analysis is presented for two plane-strain problems.
Accounting for the flexibility of nodes in the design of steel mesh dome
Authors: Kanaev Egor , Demidova Daria , Zimin Sergey
Published: December 2018

This paper presents the results of a study of the stress-strain state of a geodesic dome covering the planetarium designed in the city of Nizhny Novgorod. Four design schemes were created in the SCAD with different types of node modeling. A comparative analysis of the effect of the strain capacity of the “BrGTU” type unit on the stress-strain state of the dome cover has been carried out. The results are obtained on the change in the displacements of the structure nodes and internal forces in the dome bars, with rigid and hinged mates. The option of increasing the diameter of high-strength bolts to reduce the overall deformability of the system is considered. On the basis of the obtained results, it was concluded that it is necessary to take into account the strain capacity of the semirigid connections when designing mesh steel domes.
Fluid mechanics tests of separator-reheater turbines
Authors: Egorov Mikle , Suslov Vyacheslav
Published: December 2018

The main aim of the current work is to increase operation efficiency and reliability of moisture separator-reheaters and turbines of NPPs. As the experience from MSR-500-1 operation showed the presence of large disperse moisture leads stops of the turbine. The high wetness level of steam downstream of separating devices observed since the first years of operation. Results from tests of the modernized separator-reheaters of the first unit at the Smolensk NPP with «Powervane» louvers developed by Balcke-Durr company are presented. Results from studies on the determination of wetness of the steam at the outlet from the separating part of the MSR-14, MSR-24, which demonstrate advantages of modernized construction are discussed. Modernization of separator-reheaters of the turbines TG-1, TG-2 resulted in eliminating non-uniformity of wetness over the perimeter and height of the steam space downstream the separation units. Success in modernization was caused by arranging separate outlets for moisture depositing at the walls, bottom of the inlet chamber. According to the results of the carried out studies an average value of the wetness at the outlet of the separation units was 0.6% which is close to the design value 0.5%.
Design criteria for novel supersonic nozzles with high pitch-chord ratio
Authors: Smirnov Maksim , Kirillov Aleksandr , Lapshin Kirill , Porshnev Gennadii , Laskin Aleksandr
Published: December 2018

High pitch-chord ratio turbine stages are a novel class of high enthalpy drop impulse turbines. Significant limitation of traditional design approach for such turbines is a low partial admission rate due to low volumetric flow rates. The main idea of high pitch-chord ratio design is in increase of the stage load coefficient with decrease of the flow angles. The latter allows to provide higher partial admission rate and, hence, higher stage efficiency compared with the traditional design approach. As a consequence, efficiency of the high pitch-chord ratio stages varies between 65% and 75%, whereas partially admitted stages efficiency tend not to exceed 60%. High pitch-chord ratio nozzles have a rectangular cross section. This feature leads to a vortex pair occurrence in a nozzle flow path. An interaction of these vortices for transand supersonic stages leads to additional losses and comparably low nozzle efficiency. The present paper aimed at first, establishing the design criteria which are essential for the nozzle efficiency, and, second, finding the optimal ratios of the proposed criteria. CFD simulation approach is used for the study. The gained deliverables are helpful for increasing of the nozzle velocity ratio.
Studies of turbulent coolant mixing flows in the new generation reactors
Authors: Dmitriev Sergei , Khrobostov Alexander , Legchanov Maksim , Ryazanov Anton
Published: December 2018

Due to studying of the flow parameters in the downcomer the bottom plenum of the nuclear reactor can be carried out with the help of CFD programs, the work is devoted to experimental researches in the field of pressurized water reactor with the purpose of creation of benchmarks for verification of domestic codes of computational hydrodynamics. Such data must have high spatial resolution, high resolution and high accuracy of the measurements. It makes necessary to apply complex experimental methodologies, measurement instrumentation and careful adjustment of experimental methodology. So a brief description of the experimental stand and its research methodology is given. A spatial conductometric measuring system that allows to study the processes of turbulent mixing of flows in the complex geometry of the nuclear reactor is presented. The description of experimental research and their results are presented. Conclusions are drawn about the prospects of using spatial conductometry as a vortex-resolving measurement method.
Determination of the beginning the Steady-State for controlled processes in monitoring systems with limited resources
Authors: Leontiev Vladimir , Sorokin Alexander , Saradzhishvili Sergey
Published: December 2018

This paper describes the basic approach for determination of the steady-state conditions of physical processes such as boiling or other phase transitions in control systems with limited resources. In this research, we consider the particular case of a control system that should determine the moment when the water temperature reaches boiling point. In different systems, the accurate determination of the boiling point is important, because it results in other functions such as switching off or transitioning to other states. Hence, we explore the possibility of applying our approach in systems with limited resources, using cheap temperature inertial sensors. During the investigation, we encountered a delay in identifying the boiling point, caused by inertia. These issues demonstrate the need for the further improvement of the suggested approach in this particular case. However, generally our results indicate the applicability of this approach for control systems.
Applicability of a Fast Fourier Transform for a harmonic analysis
Authors: Gritsutenko Stanislav , Korovkin Nikolay
Published: December 2018

Applicability for Fast Fourier Transform of signals with low entropy are discussed in this article. Firstly, FFT is studied for case of a harmonics set shifted relative to samples of FFT. A theoretical basis is analysed. A conclusion is that the error is goes down but it is high enough yet. Next, a method on a base of convolution with a harmonics spectrum neighbourhood and window’s spectrum is presented. A conclusion is that an amplitude error for harmonic measuring becomes good but a phase error continues to be bad one. Finally, a conclusion is that FFT concedes accuracy direct measuring methods. In case of accordance of characteristics of measure, FFT concedes in number of calculations.
Structural heterogeneities of tube steels taken into account in the development of contactless magnetometry of pipeline systems
Authors: Ermakov Boris , Ermakov Sergey , Nikiforova Oksana , Shaposhnikov Nikita
Published: December 2018

One of the problems facing gas and oil pumping companies is the aging of pipelines, whose service life is rapidly approaching, or even exceeding, the resource planned during design. The only possible way to evaluate the possibility of further safe operation and residual life of pipelines is to conduct studies of the actual state of the parent metal and welded pipe joints. However, the direct investigation of metal pipes is practically impossible due to the linear dimensions of objects and their position. The analysis of the state of the pipeline system can only be made with the help of contactless, most often magnetic methods. Interpretation of magnetograms and detection of defects that are dangerous for the operation of pipes is one of the most difficult problems facing defectoscopists, which can be solved only by creating a library of structures and defects. This paper presents the results of a structural analysis of the metal of pipes, which must be taken into account when interpreting the results of magnetograms. These results constitute a part of the library of defects in pipeline systems developed in SPbPU.
Estimation of evacuation time with elevator application in high-rise buildings
Authors: Gravit Marina , Dmitriev Ivan , Kuzenkov Kirill
Published: December 2018

The article considers elevator application as an integral part of the main evacuation path from high-rise multi-storey buildings and structures. The evacuation ways are rather long in this building type. It makes the evacuation process difficult and dangerous, and sometimes physically impossible. The combined evacuation with using of vertical transport can solve this problem. The complex of buildings of various storeys (20, 30 ... 60) was modeled in the program complex Pathfinder. We determine and compare the values of the evacuation time for different health categories people during movement on stairs and with particular elevator use. The percentage of acceleration of evacuation is given. It is shown that evacuation along the staircase develops as a linear function. The necessary of the joint stair-lift evacuation method increases with the height of the building. We offer the human flow ratios for evacuating people in simulated buildings (20, 30 ... 60), which is made taking into account the various mobility categories.
Environmental express monitoring of territory and water bodies at various stages of construction and improvement
Authors: Myazin Nikita , Neronov Yuri , Dudkin Valentin , Davydov Vadim , Yushkova Victoria
Published: December 2018

The article substantiates the need for continuous monitoring of the state of the environment both in the territories of the object under construction and in the areas of improvement works. The method of nuclear-magnetic spectroscopy is proposed, which allows carrying out ecological express monitoring of the state of condensed media (for example, water, silt, various mixtures, etc.) in real time. The results of ecological express monitoring are presented and recommendations for its more effective application are given.
Security of construction sites: risk-management
Authors: Deordiev Sergei , Kudrin Victor , Plyasunova Mariya
Published: December 2018

This article has certain goals and tasks for solving some engineering problems. The analysis of the situation regarding the applicability of risk management in the construction industry of the Russian Federation is presented. The reasons for the low prevalence of this means of ensuring the mechanical safety of buildings and structures are revealed. Examples of the application of risk management in the West, as well as examples and reasons for non-use in Russia are given. Measures and recommendations are proposed to change this situation in the construction sector. References are given to sources with weighty arguments for the application of building safety.
Validation &Verification context for NPP design and construction
Authors: Vladislav Gvozdev , Galina Kozinetc
Published: December 2018

Nuclear power, as one of the most sophisticated and technologically advanced industry sectors, sets very demanding safety requirements. Fulfilment thereof is mostly to be implemented and justified at the design and construction stages. The process of Validation and Verification (V&V) for such facilities should cover all possible disciplines and cases, therefore a systematic approach to its organization is needed, which is not fully. The article objective is to determine the reasons for such strict safety requirements and explore the methods for achieving it, including the V&V process, as well as determining the factors (V&V dimensions) forming the V&V context, which is going to be used for choosing a specific type of V&V activities (to be conducted during the design and construction phases). Then, the article shall determine the interrelations between disciplines that use the V&V results depending on the context. V&V Context is setting up the parameters defining specific V&V activities. Generally, the V&V Context includes the following dimensions: Discipline (Construction, Electrical, Instrumentation and Control), Hierarchy (Design Levels – Plant, System, Components and Structures levels), NPP Construction Project phases (Design, Construction, Installation, Commissioning). The V&V process is a complex one and it will be different for each combination of the above-mentioned V&V dimensions together forming the V&V Context.
Fourth industrial revolution and the paradigm change in engineering education
Authors: Sakhapov Rustem , Absalyamova Svetlana
Published: December 2018

The article discusses the main features of the fourth industrial revolution and its impact on the transformation of the labor market and the transition to a new paradigm of education. Authors analyze new requirements for the graduates competence and modern world educational trends. Much attention is paid to strengthening of the project nature of education, blurring the distinction between traditional technical and humanitarian education. Moreover, the authors examine the shift of engineering work with its basic elements – invention, engineering, and design in the field of technical engineering in the area of economic, financial, social, cultural, anthropological design. This requires the creation of new interdisciplinary courses, the revision of the classical approaches to engineering and humanitarian education. The article explores the personalization of the educational trajectories, artificial intelligence as a teacher, e-learning technologies and simulators, information educational environment.
Analysis of tools for assessing the terms of working environment of foreigners
Authors: Svetlakova Anna , Kaverzneva Tatiana , Tarkhov Dmitriy , Belina Natalia
Published: December 2018

The critical review presents an analysis of foreign studies designed to assess the state of working conditions. The aim of the work is to identify the main areas of research that can be adapted for Russian enterprises. It was found that there are several foreign instruments for assessing the state of working conditions, on the basis of which a new methodology applicable to Russian enterprises can be formed, which will greatly contribute to the prevention of accidents at the workplace.
Optimal regular reflection of shock and blast waves
Authors: Chernyshov Mihail , Tyapko Alexandr
Published: December 2018

The regular reflection of an oblique steady shock in supersonic gas flow is considered. The static pressure extremum conditions after the point of reflection of the shock with fixed strength depending on oncoming flow Mach number are determined analytically. The obtained results are applied to solution of the mechanically equivalent problem of the reflection of a propagating shock from an inclined surface. Non-monotonic variation of the mechanical loads on the obstacle with respect to its inclination angle is shown; the obstacle slope angles that correspond to pressure minima downwards of the unsteady shock reflection point are determined analytically.
On the possibility of using ion-exchange filters for water treatment
Authors: Germanova Tatiana
Published: December 2018

This study was conducted with the aim of preliminary assessment of the total use of the working exchange capacity of cation-exchangers during ion-exchange filtration of surface waters. The chemical composition of natural waters in Russia depends on many factors, which affects the performance indicators during operation of water treatment equipment. Comparison of geochemical indicators of natural waters of the Ob River basin at specific locations of water withdrawal in the Ural Federal District of Russia was carried out. For several compositions of natural waters, the calculation of two-stage ion-exchange filtration in the water treatment scheme for heat and power plants has been carried out. The possibility of rational use of ion-exchange filtration at the first stage of water purification and low efficiency of the use of ion-exchange filtration at the second stage of filtration for these plants is shown.
Modes of operation and design features of pulse cables for the ITER project
Authors: Doronin Mikhail , Greshnyakov George , Korovkin Nikolay
Published: December 2018

Cables with high current capacity are used in power devices, including special-purpose ones operating in impulse modes. It is important to ensure low inductance of such cables, because these type cable products are often used as connecting products. This article discusses the problems that arise in the design and manufacture of special low-inductance impulse cables (SLIC) for power supply and protection of the superconducting magnetic system of the ITER reactor (France), the distinguishing features of which are the optimum ratio of insulation thickness and throughput at low inductance.
Methodical approaches to energy supply with usage of renewable energy sources on objects of transport infrastructure of federal importance
Authors: Shestakov Vyacheslav , Novikova Olga , Melnichenko Artem , Luchnikova Anastasia
Published: December 2018

In this article we consider the potential possibility of using renewable energy sources for the construction of transport infrastructure facilities of the Federal importance. We analyzed major promising projects for the construction of roads and bridges for the period until 2030 year, considered a step-by-step scheme for energy supply of a large facility, using the example of the Kerch bridge, and made an analysis of the potential usage of hybrid power plants based on renewable energy sources for the implementation of projects. We developed methodological approaches to the implementation of large-scale projects that would allow one to take into account not only economic efficiency, but all the positive effects that can be achieved from the project.
Graphic-analytical method in architectural assessment urban visual environment
Authors: Glukhova Daria , Katilova Julia , Krupina Anastasia
Published: December 2018

Not only chemical or physical pollution is a problem for environment. The visual environment pollution becomes irreversible problem. Because of the basis of modern construction is the principles of simplified modeling. A lot of same elements on the facade of high-rise building create an unfavorable environment for visual perception. It can leads to visual deterioration, mental health and other health concerns. There are not enough accurate methods for visual aggressiveness assessment. In this article we offer use graphic-analytical method for determine the degree of aggressiveness of building’s visual environment. As the result, we determined the percentage of same elements on the facades of two buildings by using a grid.
Adsorption of rare earth elements using bio-based sorbents
Authors: Kosheleva Arina , Atamaniuk Iryna , Politaeva Natalia , Kuchta Kerstin
Published: December 2018

Rare earth elements (REEs) have recently received significant attention due to their irreplaceable industrial application for the number of crucial advanced technologies in production of permanent magnets, batteries, luminescence lamps, lasers and other electronic and electrical goods. These technologies have been strongly affecting present consumption of REEs as well as looking for alternative sources, that would guarantee their sufficient supply for the future demand. This study investigates one of the possible and widely employed techniques for the efficient and at the same time, environmentally friendly recovery of REEs by adsorption using bio-based adsorbents. Overall, three bio-sorbents with different composition (residual biomass originated from agriculture and bio-refineries) were examined to study removal efficiency of the 7 most commonly used REEs in mixed aqueous solution. Batch adsorption experiments were carried out at the room temperature, varying the pH value (pH=1,54; 4,24) and different initial concentration of REEs to determine optimum condition for their recovery. Results revealed that removal efficiency for most of the REEs was much higher at pH=4,24 and reached 70-100% for the minimal concentrations and 30-40 % at maximal initial concentrations respectively. Adsorbent containing residual biomass and chitosan showed to be the most effective bio-sorbent for recovery of most of the REEs. In order to describe and fit the obtained data Langmuir and Freundlich isotherms models were employed.
Wastewaters of meat-processing enterprise: assessment of genotoxic potential
Authors: Ivanchenko Olga , Khabibullin Rustem , Bhat Rahat
Published: December 2018

Environmental pollution and ecosystem dysfunction are one of the most important problems of the today’s world. Assessment of toxigenic properties of effluents from the meat-processing enterprise was carried out using the short-term microorganisms biotests in vitro. Both native waste water and its ether and water fractions were investigated. The probes’ sterilization was carried out by filtration through the sterile membrane filters Synpor with pores diameter of 0.45 m. Mutagenic activity of wastewaters was determined using the Salmonella/microsomes plate with in vitro metabolic activation and without metabolic activation (Ames test). As a metobolic activation the rat liver microsomes were used. Studying of the DNA-damaging activity was carried out using the suspension method modification on the mutant Escherichia coli strains, in which the functioning of one reparation systems is suppressed: uvrA-, recAand рol A-. Native waste water doesn’t have an influence on the mutant strains recAand рol A-, its survivability degree is in the range 96-100%. However, DNA-damaging action was registered for the strain with the damaged excision repair (uvrA-), survivability of which was 81.31%. Ames test of wastewater and its fractions didn’t reveal any mutagenic activity. The tests used in this work allow one to comprehensively estimate the genetic danger of the enterprise wastewaters within a short time and are recommended as test-systems for monitoring the ecological safety of wastewaters.
Sorption properties of materials based on residual biomass
Authors: Smyatskaya Yulia , Kosheleva Arina , Taranovskaya Elena
Published: December 2018

In this paper, we consider the possibility of using inexpensive and effective sorption materials based on plant raw materials, such as fruit rind, vegetable waste, fallen leaves, and the use of phytosorbents for the purification of sewage containing heavy metals and petroleum products. The use of vegetable waste for the manufacture of sorbents is a priority for solving environmental problems. It is suggested to use residual biomass as a sorption material, which is formed after extraction of lipids from C. sorokiniana microalgae and duckweed Lemna minor. To increase the sorption capacity, it was proposed to thermally modify the residual biomass. The optimum heat treatment conditions were 450 °C for 20 minutes with limited access to oxygen. The obtained biomass allows one to extract ions of heavy metals with efficiency of 91-93% for ions of lead, cadmium, zinc and copper.

To increase the sorption capacity (A, mg/g) of the residual biomass, heat treated waste from the agro-industrial complex and chitosan were proposed as additives. The addition of chitosan makes it possible to obtain a sorption material in the form of granules, which is convenient to use. For the sorption materials obtained, microstructural studies were carried out, which allowed us to substantiate the sorption properties of the materials. The physical and mechanical properties of sorbents, such as abrasion, grindability, allow us to offer new materials for use on an industrial scale. In the article, a technological scheme for obtaining sorption materials from residual biomass is given.
Motion preservation surgery: excision of juxta C5–C6 intervertebral disc osteoid osteoma using 3D C-arm based navigation: technical report
Authors: Kulkarni Arvind , Patel Ankit
Published: December 2018

Introduction: Precise targeted excision of the C5–C6 osteoid osteoma with placement of reference array on clavicle with minimal disturbance of anatomy and motion.

Methods: A 20-year-old male presented with an osteoid osteoma in the superior end plate of the C6 vertebra abutting the spinal canal causing intractable pain. The authors curetted the nidus using a 3D C-arm-based intraoperative scan integrated with an optical navigation system through a minimal access anterior cervical exposure. The patient reference array was affixed to the left clavicle using a threaded pin.

Results: The postoperative CT-scan revealed complete excision. Follow-up MRI and CT after 12 months revealed C5–C6 intervertebral disc to be intact without evidence of any tumor recurrence. VAS for neck pain improved from 8/10 to 2/10 immediately postoperatively and 0/10 at 1 year follow-up with no limitation of cervical movement. A motion segment was preserved with this technique.

Conclusions: Navigation allowed safe curettage of the nidus with minimal disturbance to the anatomy and motion. The site of attachment of patient reference array on clavicle can be recommended as stable, meeting all the criteria for optimal accuracy and stability.
Akne-Triade als paradoxe Reaktion auf Therapie mit dem IL-6-Inhibitor Tocilizumab
Authors: Troyanova-Slavkova S. , Rühmer P. , Pötzsch S. , Kowalzick L.
Published: December 2018

Als Akne-Triade bezeichnet man eine Kombination aus Acne conglobata und intertriginöser Akne axillär (sog. Hidradenitis suppurativa) und inguinal/genitoanal. Eine Perifolliculitis capitis abscedens et suffodiens und/oder Steißbeinfisteln (Akne-Tetrade) können hinzutreten. Es handelt sich dabei um eine schwere, chronisch-rezidivierende, furunkuloide und hochentzündliche Form der Akne mit Haut und Subkutis betreffender abszedierender, fistelnder und vernarbender Entzündung, ausgehend von der Haarbalg-Talgdrüsen-Einheit. Das Biologikum Tocilizumab (Handelsnamen RoActemra®) ist ein humanisierter, monoklonaler Antikörper gegen den Interleukin-6 (IL-6)-Rezeptor zur Behandlung der rheumatoiden Arthritis (RA) und der schwersten Form des kindlichen Rheumas, der systemischen juvenilen idiopathischen Arthritis (sJIA; Syn. Morbus Still). Interleukin-6 ist ein Zytokin, das im menschlichen Körper Entzündungsreaktionen moduliert. Hier beschreiben wir den Fall eines 17-jährigen Patienten, der unter der Therapie mit Tocilizumab die schwerste Form einer Akne-Triade als paradoxe Reaktion entwickelte.
Druckverhältnisse bei Verwendung miniaturisierter PNL-Schäfte mit 9,5 Ch bzw. 12 Ch Außendurchmesser für die minimalinvasive perkutane Nephrolitholapaxie (MIP): Ex-vivo-Druckstudien
Authors: Huusmann Stephan , Wolters Mathias , Schilling David , Kruck Stephan , Bader Markus , Tokas Theodoros , Herrmann Thomas , Nagele Udo ,   Training and Research in Urological Surgery and Technology (T.R.U.S.T.)-Group
Published: December 2018

Hintergrund In den letzten Jahren wurde die Entwicklung miniaturisierter Amplatz-Schäfte für die perkutane Nephrolitholapaxie mit dem Ziel eines verringerten Nierentraumas vorangetrieben. Bisherige Studien konnten zwar vergleichbar gute Steinfreiheitsraten im Vergleich zur herkömmlichen PNL bestätigen, jedoch zeigten sich ebenfalls vergleichbare Häufigkeiten postoperativen Fiebers bzw. Septikämien. Als mögliche Ursache hierfür wird der Einfluss der intraoperativen intrapelvinen Drücke aufgrund verwendeter Spülung diskutiert. Ziel der vorliegenden Ex-vivo-Studie war der Vergleich der intrapelvinen Druckverhältnisse unter Verwendung der miniaturisierten 9,5 Ch- bzw. 12 Ch-Amplatz-Schäfte mit dem bereits voruntersuchten 17,5 Ch-MIP M-Schaft.

Material und Methoden Die Schäfte wurden an einem perfundierten Schweinenierenmodell frisch geschlachteter Schweine unter verschiedenen Perfusionsdrücken evaluiert. Der Spüldruck wurde zum einen über eine Spülpumpe (Uromat E.A.S.I. Pumpe, Karl Storz, Tuttlingen, Deutschland) oder per Schwerkraft erzeugt. Über einen transparenchymatös eingebrachten Urodynamikkatheter konnte der intrapelvine Druck kontinuierlich gemessen werden. Es wurden zusätzliche Analysen mit aktiver Flüssigkeitsabsaugung über einen einliegenden Ureterkatheter durchgeführt.

Ergebnisse Der intrapelvine Druck stieg in den Messungen mit moderaten Spüldruckverhältnissen sowohl durch Spülpumpe als auch durch Schwerkraft für beide Schaftgrößen nicht über 40 cmH2O (entsprechend 30 mmHg). Unter Verwendung einer aktiven Flüssigkeitsabsaugung konnten keine bemerkenswerten Druckunterschiede detektiert werden. Bei sehr hohen Spüldrücken konnte sowohl bei Verwendung der Spülpumpe als auch für die Spülung mit Schwerkraft ein deutlicher Anstieg der intrapelvinen Druckverhältnisse unter Verwendung des 9,5 Ch-Schaftes nachgewiesen werden.

Schlussfolgerungen Beide miniaturisierten MIP-Schäfte können mit vergleichbar günstigen Druckeigenschaften wie das etablierte 17,5 Ch-MIP-Set aufwarten. Trotz deutlicher Reduzierung des Schaftdurchmessers bleibt der intrapelvine Druck bei moderaten Spüldrücken unter 40 cmH2O und somit im nicht bedenklichen Bereich.
Endoscopic ultrasound-guided through-the-needle microforceps biopsy in the evaluation of pancreatic cystic lesions: a multicenter study
Authors: Yang Dennis , Samarasena Jason , Jamil Laith , Chang Kenneth , Lee David , Ona Mel , Lo Simon , Gaddam Srinivas , Liu Quin , Draganov Peter
Published: December 2018

Background and study aims Accurate diagnosis and classification of pancreatic cysts (PCs) remains a challenge. The aims of this study were to: (1) evaluate the safety and technical success of a novel microforceps for EUS-guided through-the-needle biopsy (TTNB) of PCs; and (2) assess its diagnostic yield for mucinous PCs when compared to FNA cyst fluid analysis and cytology.

Patients and methods This was a multicenter retrospective analysis of 47 patients who underwent EUS-FNA and TTNB for PCs between January 2014 and June 2017. Technical success was defined as acquisition of a specimen adequate for cytologic or histological evaluation. Cyst fluid carcinoembryonic antigen (CEA) was used to initially categorize cysts as non-mucinous (CEA < 192 ng/mL) or mucinous (CEA ≥ 192 ng/mL). Final diagnosis was based on identifiable mucinous pancreatic cystic epithelium on cytology, microforceps histology and/or surgical histology when available.

Results Forty-seven patients with PCs (mean size 30.7 mm) were included. TTNB was successfully performed in 46 of 47 (97.9 %). Technical success was significantly lower with FNA (48.9 %) compared to TTNB (85.1 %) (P < .001). For cysts with insufficient amount of fluid for CEA (n = 19) or CEA < 192 ng/mL, the cumulative incremental diagnostic yield of a mucinous PC was significantly higher with TTNB vs. FNA (52.6 % vs 18.4 %; P = .004). TTNB alone (34.4 %) diagnosed more mucinous PCs than either CEA ≥ 192 ng/mL alone (6.3 %) or when combined with FNA cytology (9.4 %). One episode of self-limited bleeding (2.1 %) and one of pancreatitis (2.1 %) occurred.

Conclusions EUS-TTNB is safe and effective for evaluating PCs. TTNB may help increase the diagnostic yield of mucinous PCs.
Motivationale Faktoren für die Präferenz der
Fachrichtung Allgemeinmedizin – eine quantitative Untersuchung unter
Medizinstudierenden NRWs für eine zielgerichtete
Nachwuchsgewinnung
Authors: Funkhouser Greta Joan , Ostermann Thomas , Sönnichsen Andreas , Pucher Katharina K.
Published: December 2018

Ziel der Studie In Anbetracht des prognostizierten
Allgemeinmediziner-Mangels führten wir eine Online-Umfrage unter
allen Medizinstudierenden Nordrhein-Westfalens durch, um Faktoren
für die Entscheidung Medizinstudierender zur Fachrichtung
Allgemeinmedizin (AM) zu identifizieren und die Stärke der
Zusammenhänge zwischen Faktoren und Fachrichtungswahl zu
quantifizieren.

Methodik Um Beweggründe für und gegen die
Fachrichtungswahl AM zu identifizieren wurde eine Faktorenanalyse mit den
Angaben von 3976 Umfrageteilnehmern (22,6% aller eingeladenen
Medizinstudierenden) durchgeführt. Die Stärke der
Zusammenhänge zwischen extrahierten Faktoren und Fachrichtungswahl
wurden mittels Regressionsanalysen für 2862 Teilnehmer ermittelt,
die sich eher für oder gegen AM positioniert hatten. Adjustiert
wurde für relevante Populationsmerkmale.

Ergebnisse Fünf Faktoren wurden identifiziert. Signifikante
Zusammenhänge zur Fachrichtungswahl AM zeigten 4 dieser Faktoren.
„Umfassender Patientenkontakt“ (OR 4,02; 95% KI
[3,5–4,6]), und „flexible Arbeitszeiten“ (OR 1,35;
95% KI [1,2–1,5]) stellen Beweggründe für
die Fachrichtungswahl AM dar, obwohl „höhere(s)
Karrierechancen, Einkommensmöglichkeiten & Ansehen in
anderen Fachrichtungen“ (OR 1,14; 95% KI [1,0–1,3])
gesehen werden. Bessere Möglichkeiten der „Spezialisierung,
Forschung und Teamarbeit in anderen Fachrichtungen“ stehen einer
Wahl von AM als Fach entgegen (OR 0,55; 95% KI
[0,5–0,6]).

Schlussfolgerungen Der Nachwuchsgewinnung dienlich wären die
strukturierte Förderung studentischen Interesses am Patientenkontakt
in Lehrpraxen, mehr Spezialisierung, Forschung und Teamarbeit durch
verbesserte allgemeinmedizinische Strukturen an Universitäten und
eine weitere Flexibilisierung der Arbeitszeiten.
Lhermitte-Duclos Disease with Cervical Arteriovenous Fistula
Authors: Haq Anwar , Alzahrani Ibrahim , Shail Essam , Almubarak Abdulaziz
Published: December 2018

Lhermitte-Duclos disease is a rare condition with less than 250 cases reported in the literature. It was considered a neoplastic or hamartomatous growth in the cerebellum. It commonly presents with symptoms of high intracranial pressure or obstructive hydrocephalus. Surgical resection is often curative. The lesion is associated with PTEN gene mutation, and it is considered to be one of the diagnostic criteria of Cowden's syndrome. Vascular tumors are reported in this syndrome, including glioblastomas and meningiomas. Furthermore, central nervous system vascular lesions were also reported in Lhermitte-Duclos disease, such as deep venous anomalies and brain arteriovenous fistulas. A report of an asymptomatic spinal cervical AVF in a patient with Lhermitte-Duclos disease was published in 2006. We present the second case of Lhermitte-Duclos disease associated with an asymptomatic spinal cervical AVF in a 17-year-old young woman with literature review of central nervous system vascular lesions in Lhermitte-Duclos disease.
UBTF Mutation Causes Complex Phenotype of Neurodegeneration and Severe Epilepsy in Childhood
Authors: Laššuthová Petra , Štěrbová Katalin , Haberlová Jana , Vyhnálková Emílie , Neupauerová Jana , Staněk David , Šedivá Marie , Kršek Pavel , Seeman Pavel , Sedláčková Lucie
Published: December 2018

Introduction Neurodegenerative diseases of childhood present with progressive decline in cognitive, social, and motor function and are frequently associated with seizures in different stages of the disease. Here we report a patient with severe progressive neurodegeneration with drug-resistant epilepsy of unknown etiology from the age of 2 years.

Methods and Results Using whole exome sequencing, we found heterozygous missense de novo variant c.628G > A (p.Glu210Lys) in the UBTF gene. This variant was recently described as de novo in 11 patients with similar neurodegeneration characterized by developmental decline initially confined to motor development followed by language regression, appearance of an extrapyramidal movement disorder, and leading to severe intellectual disability. In 3 of the 11 patients described so far, seizures were also present.

Conclusions Our report expands the complex phenotype of neurodegeneration associated with the c.628G > A variant in the UBTF gene and helps to clarify the relation between this one single recurrent pathogenic variant described in this gene to date and its phenotype. The UBTF gene should be considered a novel candidate gene in neurodegeneration with or without epilepsy.
TULA-2 Deficiency Enhances Platelet Functional Responses to CLEC-2 Agonists
Authors: Kostyak John , Mauri Benjamin , Dangelmaier Carol , Patel Akruti , Zhou Yuhang , Eble Johannes , Tsygankov Alexander , McKenzie Steven , Kunapuli Satya
Published: December 2018

Platelet activation is essential for hemostasis. Central to platelet activation are the signals transmitted through surface receptors such as glycoprotein VI, the protease-activated receptors, and C-type lectin-like receptor 2 (CLEC-2). CLEC-2 is a HemITAM (hem-immunoreceptor tyrosine activation motif)-bearing receptor that binds podoplanin and signals through spleen tyrosine kinase (Syk). T-cell ubiquitin ligand-2 (TULA-2) is a protein tyrosine phosphatase that is highly expressed in platelets and targets phosphorylated Y352 of Syk. We wanted to determine whether TULA-2 regulates Syk phosphorylation and activity downstream of CLEC-2. To that end, we used TULA-2 knockout mice and wild-type (WT) littermate controls. We found that TULA-2 deficiency enhances the aggregation and secretion response following stimulation with an excitatory CLEC-2 antibody or the CLEC-2 agonist rhodocytin. Consistently, Syk phosphorylation of Y346 is enhanced, as well as phosphorylation of the downstream signaling molecule PLCγ2, in TULA-2 knockout platelets treated with either CLEC-2 antibody or rhodocytin, compared with WT control platelets. Furthermore, the kinetics of Syk phosphorylation, as well as that of PLCγ2 and SLP-76, is enhanced in TULA-2 knockout platelets treated with 2.5-μg/mL CLEC-2 antibody compared with WT platelets. Similarly, thromboxane production was enhanced, in both amount and kinetics, in TULA-2−/− platelets treated with 2.5-μg/mL CLEC-2 antibody. TULA-2 acts as a negative regulator of CLEC-2 signaling by dephosphorylating Syk on Y346 and restraining subsequent Syk-mediated signaling.
Transport of active particles induced by wedge-shaped barriers in straight channels with hard and soft walls
Authors: Wu Jian-Chun , Lv Kui , Zhao Wen-Wen , Ai Bao-Quan
Published: December 2018

The transport of active particles in straight channels is numerically investigated. The periodic wedge-shaped barriers can produce the asymmetry of the system and induce the directed transport of the active particles. The direction of the transport is determined by the apex angle of the wedge-shaped barriers. By confining the particles in channels with hard and soft walls, the transport exhibits similar behaviors. The average velocity is a peaked function of the translational diffusion, while it decreases monotonously with the increase of the rotational diffusion. Moreover, the simulation results show that the transport is sensitive to the parameters of the confined structures, such as the pore width, the intensity of potential, and the channel period.
Generalized molecular solvation in non-aqueous solutions by a single parameter implicit solvation scheme
Authors: Hille Christoph , Ringe Stefan , Deimel Martin , Kunkel Christian , Acree William E. , Reuter Karsten , Oberhofer Harald
Published: December 2018

In computer simulations of solvation effects on chemical reactions, continuum modeling techniques regain popularity as a way to efficiently circumvent an otherwise costly sampling of solvent degrees of freedom. As effective techniques, such implicit solvation models always depend on a number of parameters that need to be determined earlier. In the past, the focus lay mostly on an accurate parametrization of water models. Yet, non-aqueous solvents have recently attracted increasing attention, in particular, for the design of battery materials. To this end, we present a systematic parametrization protocol for the Self-Consistent Continuum Solvation (SCCS) model resulting in optimized parameters for 67 non-aqueous solvents. Our parametrization is based on a collection of ≈6000 experimentally measured partition coefficients, which we collected in the Solv@TUM database presented here. The accuracy of our optimized SCCS model is comparable to the well-known universal continuum solvation model (SMx) family of methods, while relying on only a single fit parameter and thereby largely reducing statistical noise. Furthermore, slightly modifying the non-electrostatic terms of the model, we present the SCCS-P solvation model as a more accurate alternative, in particular, for aromatic solutes. Finally, we show that SCCS parameters can, to a good degree of accuracy, also be predicted for solvents outside the database using merely the dielectric bulk permittivity of the solvent of choice.
Note: A simple laser shutter with protective shielding for beam powers up to 1 W
Authors: Colquhoun Craig D. , Di Carli Andrea , Kuhr Stefan , Haller Elmar
Published: December 2018

We present the design of an inexpensive and reliable mechanical laser shutter and its electronic driver. A camera diaphragm shutter unit with several sets of blades is utilized to provide fast blocking of laser light and protective shielding of the shutter mechanism up to a laser beam power of 1 W. The driver unit is based on an Arduino microcontroller with a motor-shield. Our objective was to strongly reduce construction effort and expenditure by limiting ourselves to a small number of modular parts, which are readily available. We measured opening and closing durations of less than 800 μs, and a timing jitter of less than 25 μs for the fastest set of blades. No degradation of the shutter performance was observed over 5·104 cycles.
Perspective: Excess-entropy scaling
Authors: Dyre Jeppe C.
Published: December 2018

This article gives an overview of excess-entropy scaling, the 1977 discovery by Rosenfeld that entropy determines properties of liquids like viscosity, diffusion constant, and heat conductivity. We give examples from computer simulations confirming this intriguing connection between dynamics and thermodynamics, counterexamples, and experimental validations. Recent uses in application-related contexts are reviewed, and theories proposed for the origin of excess-entropy scaling are briefly summarized. It is shown that if two thermodynamic state points of a liquid have the same microscopic dynamics, they must have the same excess entropy. In this case, the potential-energy function exhibits a symmetry termed hidden scale invariance, stating that the ordering of the potential energies of configurations is maintained if these are scaled uniformly to a different density. This property leads to the isomorph theory, which provides a general framework for excess-entropy scaling and illuminates, in particular, why this does not apply rigorously and universally. It remains an open question whether all aspects of excess-entropy scaling and related regularities reflect hidden scale invariance in one form or other.
Phase-sensitive photothermal imaging of ultrahigh-Q polyoxide toroidal microresonators
Authors: Knapper Kassandra A. , Horak Erik H. , Vollbrecht Cecilia H. , Heylman Kevin D. , Goldsmith Randall H.
Published: December 2018

Toroidal optical microresonators are powerful platforms for quantum optics and label-free sensing and imaging. Although these microresonators are generally fabricated from thermal oxide on silicon wafers, many benefits arise from greater flexibility for fabrication of resonators on substrates other than single-crystal silicon. The ability to perform fabrication with easily deposited polysilicon while matching the superlative optical properties of thermal-oxide would address this need. In this work, toroidal microresonators were fabricated using thermal oxide grown from polysilicon (polyoxide). These resonators possess comparable quality factors to their counterparts fabricated with oxide thermally grown from single-crystal silicon (crystalline oxide). Photothermal imaging and spectroscopy showed evidence of residual silicon and adsorbed water. Phase sensitive imaging and finite-element simulation show how subtly different thermal pathways are taken in the two material systems. Polysilicon is shown to be a viable precursor for making ultrahigh-Q toroidal microresonators.
Experimental investigation of disc partial surface texture on the generation of hydrodynamic lubricating performance under conformal contact condition
Authors: Chen Juan , Zeng Liangcai , Wu Zhenpeng , Chen Kuisheng
Published: December 2018

A series of experiments is conducted to investigate the hydrodynamic lubricant characteristics of partial surface textured specimens. The specimens are fabricated with partial surface texture. Two dimple shapes are adopted: circular and elliptic. Four kinds of texture arrangements of elliptic dimples are designed. During each test, different rotating speeds and gaps between the tested specimen and the geometric probe are set to explain the relationship between the operation condition and load-carrying capacity. We found that the load-carrying capacity is strongly affected by the operation condition, i.e. by both speed and gap. The surface textured specimens generate large hydrodynamic lift force compared with the untextured specimen. In addition, the texture arrangements exhibit a significant impact on the lubrication property.