bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental determination of the energy efficiency of rotors of vertical-axis wind turbines for autonomous power supply on land and at sea
Authors: Shishkin Nikolai , Il’in Roman
Published: December 2018

For the first time, experimental studies have been performed to assess the effect of flaps with triangular elements on the operation of the N-Darrieus and Savonius rotors. It has been established that the rotational speed of the original N-Darrieus and Savonius rotors having blades with flaps is greater than the rotation frequency of the N-Darrieus and Savonius rotors of the known construction by 18%, and the power factors of the N-Darrieus and Savonius rotors are for 17% and 19% more. Optimization of the geometrical parameters of the blades can lead to an increase in the power factor of the N-Darrieus rotor up to a value of 0.72, which is higher than the maximum possible value of 0.45 for the horizontal axis wind turbine. It is advisable to aggregate N-Darrieus rotors with Savonius rotors having a large starting torque. The upgraded N-Darrieus and Savonius rotors, as well as the combined rotors based on them, can be used in power supply systems for various objects on land and at sea.
The management system of water supply in the cities of Donbass
Authors: Maslak Viktor , Nasonkina Nadiya , Antonenko Svetlana , Gutarova Marina , Tryakina Alyona , Bereza Pavel
Published: December 2018

During more than twenty years, survey of water supply systems in the cities of Donbass was conducted. The aim of the study was to develop a strategy for managing this sector, which allows for precise monitoring of water consumption and reducing water loss. In the course of the research, water consumption metering was carried out using counters, the operation of the devices was assessed taking into account the accuracy class and installation features. It is established that the actual value of water consumption is below the standard. The water consumption decreases with an increase in the percentage of installation of water meters and with an increase in the number of tenants in an apartment. The need to bring the general house and intra-apartment meters to the same accuracy class and regulate the installation position of the water meter was identified. Based on the optimization of conditions, the program management of water supply systems by means of zoning territories and the installation of ’’clever’’ meters was proposed. Approbation of the water supply management strategy allowed within the project to reduce water losses by 20% and use the technological reserve for the modernization of the water supply system.
Adaptive control of housing and utilities infrastructure objects
Authors: Grimitlin Alexander , Krumer Roman
Published: December 2018

Transition to digital technologies in management of state, industrial facilities, energy, utilities, agriculture, etc., will significantly simplify various procedures, but if the possibility of unauthorized access to management processes and confidential information is not excluded, this might incur a number of negative consequences.
Thermodynamic analysis of a condensing evaporator in an evaporative gas turbine cycle
Authors: Mankonen Aleksi , Kaikko Juha , Vakkilainen Esa , Sergeev Vitaliy
Published: December 2018

Low efficiency is the main stumbling block preventing the widespread adoption of small-scale gas turbines in distributed energy production. The evaporative gas turbine cycle has been proposed as a way to improve efficiency, but the large number of components required make the configuration complex and expensive. The condensing evaporator is a component that simplifies the evaporative gas turbine cycle. The heat and mass exchanger device is designed for an externally fired application, which means that the flue gas stream is replaced by moist air. The air-water mixture condenses inside a tube bank, releasing heat to the evaporating water film on the other side of the tubes. Similar inventions include the tubular humidifier and the Maisotsenko compressed air saturator, which also aim to make the evaporative gas turbine cycle more economically feasible. Available theory focuses on either humidification towers or evaporative condensers in HVAC applications. The tubular humidifier has been analyzed in a similar manner as humidification tower since the flow configurations of the two components are similar. However, the theory of humidification towers is not directly applicaple to the condensing evaporator. This study proposes a method of analysis of the condensing evaporator in power generation.
Feasibility of mini combined cycles for naval applications
Authors: Barsi Dario , Costa Carlo , Satta Francesca , Zunino Pietro , Sergeev Vitaly
Published: December 2018

The objective of energy production with low environmental impact will have, in the near future, high potential of development also for naval applications. The containment of pollutant emissions can be achieved by the combined use of an innovative mini gas-steam combined cycle with thermal energy cogeneration to feed the ship thermal utilities, in place of the current Diesel engine application, and liquefied natural gas as fuel (LNG). The present work is focused on the definition of the architecture of the plant, by selecting optimal distribution of pressure and temperature and repartition of power between Gas Turbine (GT), Steam Turbine (ST) and thermal utilities, as well as on the choice and sizing of the individual components. The main purpose is the definition of a compact, high efficiency, system. The proposed basic mini-cycle ranges from 2 MW to 10 MW electric power. Thanks to the combined heat and power cogeneration plant adopted, for an overall electrical efficiency of about 30%, a total return (thermal + electricity) of about 75% can be achieved. An example of plant providing large power, in a partially modular arrangement is also proposed.
The flywheel energy storage for cargo bicycles
Authors: Hoodorozhkov Sergey
Published: December 2018

This article studies the issues of using in urban conditions a flywheel energy storage for passenger and cargo bicycles (pedicabs) in order to utilization the braking energy of the vehicle for subsequent acceleration by the flywheel. A mechanical stepless self-regulating transmission for the flywheel drive, which allows realize the regenerative braking and acceleration with maximum efficiency, is proposed. The calculation results confirm the effectiveness of proposed technical solution.
Improving the efficiency of power boilers by cooling the flue gases to the lowest possible temperature under the conditions of safe operation of reinforced concrete and brick chimneys of power plants
Authors: Ibragimov Evgeny , Cherkasov Sergei
Published: December 2018

The article presents data on the calculated values of improving the efficiency of fuel use at the thermal power plant as a result of the introduction of a technical solution for cooling the flue gases of boilers to the lowest possible temperature under the conditions of safe operation of reinforced concrete and brick chimneys with a constant value of the flue gas temperature, when changing the operating mode of the boiler.
Influence of the soil electrical conductivity in the area of the underground pipeline on energy efficiency of the cathodic protection
Authors: Kiselev Vladimir , Kalyutik Alexandr , Rouzich Evgenij
Published: December 2018

In this paper we consider main factors which have an influence on energy efficiency of the cathodic protection and analyze them. Cathodic protection is defined as the ratio of the electrical conductivity of electrolyte, which surrounds the underground (underwater) metal construction (pipeline) and its polarization resistance. The obtained results are correct first of all for the case of presence of modern qualitative insulation, which possess high dielectric properties and is made of, for example, polymers or its’ composition and is meant to be used for protection against electrochemical corrosion of the underground pipelines
Optimization of the technological solutions for recharge and boron control system at the NPP for the project AES-2006
Authors: Ulasen Anastasia , Kalyutik Aleksandr , Blagoveshchenskii Anatolii
Published: December 2018

The article considers the possible ways to optimize the technological solutions of the recharge and boron control system of nuclear power plants under construction within the AES-2006 project. The possibilities for optimization of technological solutions of the system of recharge and boron regulation of the AES-2006 project, which will not affect the reliability and efficiency of its main functions: purge-recharge of the primary circuit and boron regulation, were studied. As a result of the analysis of technological solutions and analytical calculations carried out during the work, it was found that in the system of recharge and boron regulation of the NPP within the project AES-2006 it is possible to perform optimization basing on reduction the metal content of the heat exchange equipment by reducing the surface area of the heat exchangers of the coolant outlet, reducing the power of pumps, as well as reducing the diameter of a number of main pipelines. Implementation of the proposed optimization of technological solutions will allow a more rational arrangement of the system and reduce capital costs for the construction of nuclear power plants as a whole, while not adversely affect the safety of the system and its functions.
The strength of welded structures at low climatic temperatures
Authors: Sokolov Sergey , Vasilyev Ivan , Manzhula Konstantin
Published: December 2018

Methods for the selection of steels for metal structures were analyzed in accordance with the normative documents GOST 32578-2013, ISO 20332-2015 and F.E.M.1.001. As the example the choice of steel 09G2S was confirmed for a metal structure of a crane, operated at a temperature of minus 55° C. To confirm the correctness of the choice of steel for this design and justify the allowable size of defects, welded samples were tested at temperatures from plus 20 to minus 60° C.
Thermal cracking resistance of stacking concrete blocks
Authors: Shaibakova Albina , Semenov Kirill , Barabanshchikov Yurij
Published: December 2018

In massive concrete structures there is a danger of temperature cracks. One of the measures to get rid of these type of cracks is the breakdown of an array into concreting blocks. In this paper, we consider the provision of thermal crack resistance of a massive concrete structure during the construction period. A comparative analysis of the thermally stressed state of the structure erected by one and two blocks in height is carried out. The influence of the overlap intervals of the concrete block in the calculations of thermal crack resistance was evaluated. Thermal crack resistance is evaluated by the deformation criterion. The authors found that the breakdown of the concrete structure into concreting blocks reduces the elongation deformations by 37%. The results show that increasing the overlap interval of a concrete block more effectively ensures thermal crack resistance of the structure.
Finite elements apparatus in thin-walled rods dynamics problems
Authors: Rybakov Vladimir , Dyakov Stanislav , Sovetnikov Daniil , Azarov Artur , Ivanov Sergey
Published: December 2018

The calculation of thin-walled rods is extremely relevant problem of structural mechanics and not only from the scientific standpoint, but also due to the widespread use of so-called lightweight thin-walled steel structures for construction engineering sector. Regardless of a sufficiently large number of studies connected with the statics of thin-walled rods, the dynamics of such systems have not been thoroughly studied yet. Based on one of the forward-looking theories of calculation i.e. the semi-shear theory by Slicker, the paper provides a technique for solving the dynamics problems of thin-walled rods. The stiffness and mass matrices of the finite element system are obtained for linear approximation of the form functions, and the natural vibration frequencies of the rods are calculated. The obtained solution is accomplished by the extrapolation method of estimating the accuracy of numerical methods for solving mathematical problems.
Computational study of influence of inflow port channel design on spark-ignition natural gas engine parameters
Authors: Patsey Pavel , Galyshev Yuriy
Published: December 2018

Resistance is The article presents the results of the research of a charge swirl motion influence on working process, engine parameters and NOx emissions of a spark ignition premixed natural gas engine. The charge swirl motion was organized by tangential inflow channel. The engine work process research was performed using numerical modeling of physical and chemical processes in combustion chamber. The turbulent flow in combustion chamber, spark ignition and combustion of gas fuel were simulated. The simulation shows that a tangential channel allowed organizing a swirl motion of charge and increasing turbulent kinetic energy of flow in the combustion chamber. Swirl motion greatly affects the combustion process. The increase in the turbulent kinetic energy to the spark timing made it possible to substantially reduce the combustion time of the fuel. Replacement of one original channel by a tangential channel allowed reducing emissions of nitrogen oxides NOx. Physical and chemical processes in combustion chamber were simulated in Ansys Forte.
Analysis of gas dynamics in a single-phase two-channel plasma torch at cold blowing and considering the interaction with the electric arc
Authors: Obraztsov Nikita , Frolov Vladimir , Korotkikh Mikhail , Ushomirskaya Ludmila
Published: December 2018

This article is devoted to the simulation of cold gas purge and flow taking into account the plasma arc in the channels of a single-phase two-channel high-voltage plasma torch with cylindrical electrodes. The results obtained in the process of modeling made it possible to simplify the model for further modeling, which will result in the distribution of velocities, temperatures and voltage drop on the arc depending on the time.
Analysis and modernization of real gas thermodynamic calculation for turbocompressors and detander units
Authors: Aksenov Aleksey , Kozhukhov Yury , Sokolov Mihail , Simonov Anatolei
Published: December 2018

In this work analysis, modernization and software implementation and an algorithm for thermodynamic calculation on the basis of the Benedikt-Webb-Rubin actual gas equation are performed. The work includes writing, analysis and modernization of the real gas thermodynamic calculation program. In the first part of the work data were processed to calculate real gas. In the second part, the development of the algorithm for thermodynamic calculation and its modifications is carried out. In the third part, the analysis of this algorithm is performed, revealing the main shortcomings and limits of applicability. In the fourth part of the work, the algorithm was implemented in the form of computational modules and programs, and also practical testing of these programs in the calculation of gas compressor and auxiliary equipment.
Surge protection system development in centrifugal compressor with an indicative method using numerical simulation of unsteady processes and analysis of pressure fluctuation signals
Authors: Lebedev Alexandr , Gileva Lyubov , Danilishin Alexey , Sokolov Mikhail
Published: December 2018

Nowadays, anti-surge protection system based on parametric method is widely used. The disadvantage of this anti-surge system is the fact that it is not possible to fully ensure the safe operation of the compressor at low flow conditions, because large measurement error will occur. Other method of anti-surge protection is indicative method. This method is what it is necessary to detect occurrence of rotating stall in time on the score of information criterion. Further the control decision is accepted in connection with the approach to the danger zone of surge. Indicative method is more complicated and requires special signal analysis such as wavelet analysis, correlation analysis. Also in addition to the methods of analysis, important is the length of the sample for processing unsteady pressure fluctuations and the method of its displacement on time. It is now possible to mathematically pre-simulate unsteady processes in the flow part of centrifugal compressor.
Numerical simulation of electrohydraulic processes
Authors: Mamutov Viatcheslav S. , Mamutov Alexander V.
Published: December 2018

Using the finite element software complex LS-DYNA 971, the technique of simulating processes of Electro-Hydraulic forming is developed. The law of energy deposition is obtained from semi-analytical calculation. A simulation of complex EHF process, which includes discharge chamber with electrodes, plasma channel, water, deformable blank that is formed into a rigid die, is performed using the developed technique. The simulation is validated by experimental results. The developed technique significantly extends practical usage of numerical simulation of electrohydraulic forming and other electrohydraulic-based technologies.
Low pressure water-mist nozzle with a swirl worm screw inserts
Authors: Kropotova Nadezhda , Arakcheev Alexander , Tanklevskiy Leonid , Tanklevskiy Anton
Published: December 2018

The article contains the main results of the creation of a nozzle of improved design research work. To improve application efficiency of low-pressure nozzle of water mist in automatic fire-extinguishing system (AFS), the construction of centrifugal nozzles with swirl worm screw inserts was changed. The construction features of this sprayer, methods of its testing and obtained results these tests characteristics are presented.
Methods of instrument testing of smoke detectors performance
Authors: Dubov Sergey , Babikov Igor , Vasilyev Mihail , Tanklevsky Leonid
Published: December 2018

This article is devoted to the currently relevant task - determining the real operability of the smoke detector and developing a method for the rapid diagnosis of fire detectors included in the fire alarm loop. In the process, the sensitivity of the smoke optoelectronic fire detector was checked.
Phased evacuation algorithm for high–rise buildings
Authors: Gravit Marina , Dmitriev Ivan , Kuzenkov Kirill
Published: December 2018

The article explores a new phased evacuation algorithm for high-rise buildings and structures. The necessity of using this evacuation type is justified by reducing of the human flow density, which minimizes the people injury risks and the crowd formation during the movement process. This type of evacuation prevents the appearance of clusters in local narrowing places (the floor entrance), as well as on stairway. The calculation model is made in Pathfinder PC. The scheme of organizing a phased evacuation is based on the separation of the evacuating people flows and the prevention of their crossing. The design scheme is given for the twenty-story section of a high-rise building. A detailed instruction describes the process of dividing a section into stages and determining the sequence of evacuation floors. The time delays table is calculated for each floor of the simulated twenty-storey section.
Gradient heat flux measurement as monitoring tool for the diesel engine
Authors: Mityakov Vladimir , Mityakov Andrey , Vintsarevich Artem , Gerasimov Daniil
Published: December 2018

The usage of gradient heat flux measurement for monitoring of heat flux on combustion chamber surface and optimization of diesel work process is proposed. Heterogeneous gradient heat flux sensors can be used at various regimes for an appreciable length of time. Fuel injection timing is set by the position of the maximum point on the angular heat flux diagram however, the value itself of the heat flux may not be considered. The development of such an approach can be productive for remote monitoring of work processes in the cylinders of high-power marine engines.
Investigation of the wind generator blades material resistance to the lightning current action
Authors: Adamyan Yuri , Krivosheev Sergey , Minevich Tatyana
Published: December 2018

This paper is devoted to the problems of lightning protection of composite materials of wind generator blades. The results of experimental studies for carbon fibers under different types of lightning current pulse effects are provided. A significant increase in the degree of destruction of materials is shown for the pulse approximating field experiment results as compared with the standard lightning current pulse. We show that under the impact of the standard current pulse there is no significant material destruction, and the release of the discharge products is also insignificant. Also we shown that under the impact of the current pulse having a long «tail» time period (the current pulse close to the real one) there is an ignition of the carbon fiber composite material near the edges of the feeding electrode. With this the burning process doesn’t end after the end of the current pulse. The description of the pulse current generator created for experiments is given.
Influence of extraction conditions on the recovery lipids extracted from the dry biomass of duckweed Lemna minor
Authors: Smyatskaya Yulia , Politaeva Natalia , Toumi Amira , Olshanskaya Lubov
Published: December 2018

Previous studies on the composition of lipid content of higher aquatic plants can be found in the literature. The present work aims to study the effect of various solvent extraction systems on the recovery of lipids extracted from the dry biomass of Lemna minor, using the same polar solvent (ethanol) and variating the non-polar solvent as follow: methanol-ethanol, chloroform-ethanol, hexane-ethanol, diethyl ether-ethanol, petroleum ether-ethanol at different volume ratio. The goal is to select a Sohxlet extraction method that shortens the extraction duration and increases the lipid recovery using various solvents. To intensify the extraction process, homogenization was used as a cell disruption method.

It is shown that the yield of total lipids is increased by using homogenization from 4.6% to 6.0%. When studying the influence of the solvent system, the highest yield of total lipids was obtained by using hexane-ethanol with a volume ration of 1:1 (8.0% total lipids by dry mass). The yield of lipids recovered from dry biomass of Lemna minor increases by increasing the extraction time. The optimum extraction time was found to be no more than 300 minutes. The composition of the lipid fraction is mainly represented by sterols, fatty acids and triglycerides.
Comportement à l’usure et au frottement de deux biomatériaux AISI 316L et Ti-6Al-7Nb pour prothèse totale de hanche
Authors: Fellah Mamoun , Aissani Linda , Iost Alain , Zairi Amel , Montagne Alex , Mejias Alberto
Published: December 2018

On s’est intéressé dans ce travail à l’analyse du comportement à l’usure et au frottement de deux prothèses totales de hanche en acier AISI 316L et en alliage à base de titane Ti-6Al-7Nb. Les propriétés tribologiques d’usure par glissement sont évaluées à l’aide d’un tribomètre TriboTechnic muni du logiciel tribotester, en accord avec les standards ASTM G 133–95, ISO 7148-1:2012 et ASTMG 99, en présence d’un milieu physiologique (solution de Hank) à une température de 28 à 30 °C. La bille en alumine (Al2O3) a été choisie comme antagoniste. Trois vitesses (1, 6 et 15 mm.s−1) et quatre forces normales (2,4,6 et 10 N) ont été appliquées. Après chaque essai de frottement, l’état de surface a été analysé par un microscope électronique à balayage. Le coefficient de frottement et le volume d’usure étaient plus faibles dans les échantillons testés à une force appliquée de 2 N sous une vitesse de 1 mm.s−1 (0,12 et 0,33) et (0,07 × 107 et 0,09 × 107 μm3) pour l’acier AISI 316L et le Ti-6Al-7Nb, respectivement. Les valeurs du coefficient de frottement obtenues respectent les normes imposées par le domaine du biomédical notamment au niveau de l’état de surface articulaire des prothèses de hanche.
Caractérisation physique et mécanique du bois et des fibres issus d’une palme mûre de palmier dattier
Authors: Djoudi Tarek , Hecini Mabrouk , Scida Daniel , Djebloun Youcef , Guerira Belhi
Published: December 2018

La disponibilité en quantité importante des sous-produits renouvelable des palmiers dattiers laisse envisager leur utilisation comme renfort dans les matériaux composites et les structures d’isolation. Ceci nécessite la caractérisation physico-mécanique des différentes composantes du palmier. Dans ce contexte, cette étude a été entamée pour la caractérisation d’une composante importante du palmier qui est la palme mûre. La palme étant décomposée essentiellement en deux parties, lePétioleet leRachis, la caractérisation a été portée alors sur le bois fibreux et les fibres de ces deux parties. La caractérisation physique concernera la masse volumique des fibres et de la matrice végétale (lignine) ainsi que le taux d’humidité dans les différentes parties de la palme. Les essais mécaniques ont permis de déterminer les caractéristiques mécaniques du bois fibreux et des fibres extraites des deux parties de la palme après le séchage. À l’issue de cette étude, les résultats obtenus montrent l’influence de la position de l’échantillon testé sur les propriétés physico-mécaniques. Ils ont permis également de situer ce type de bois fibreux et ces fibres parmi d’autres résultats de la littérature scientifique et d’envisager de les utiliser dans la mise en œuvre des matériaux composites et dans des éléments d’isolation.
Detailed mechanism of surface blistering in sour media
Authors: Crolet Jean-Louis
Published: December 2018

The known occurrence or absence of surface blistering (SB) are reminded, either in field failures or in HIC testing in the laboratory, i.e. in sophisticated fitness for purpose tests at low pH or in simplified acceptance tests at conventional pH values (NACE TM 0284). A previous analysis of charging severity is also reminded, together with the presence of temporary degassing barriers. Then, through an accurate modelling of charging transients, significant overshots of the hydrogen content close to surface are shown to be present soon after immersion when looking for the most resistant steels in HIC testing on full thickness samples, so that SB can be met alone in such tests. On commissioning in the field, their magnitude is necessarily much lower, so that in field failures, SB is always met together with SWC in the bulk. Conversely, overshots are totally unlikely with small specimens, short durations and medium severity, and SB is never reported in TM 0284 tests. They are also made impossible in the field by a progressive commissioning, and SWC is often reported alone in field failures. Such agreement in a very complex situation is indeed one more indirect proof of the protonic nature of dissolved hydrogen in steel.
An Overview on Genistein and its Various Formulations
Authors: Jaiswal Neha , Akhtar Juber , Singh Satya Prakash , Ahsan Farogh ,   Badruddeen
Published: December 2018

Genistein is the natural isoflavone and a phytoestrogen with a broad range of pharmacological properties, such as tyrosine and topoisomerase inhibition. It also induces apoptosis and cell proliferation inhibition, differentiates cancer cells. Added health benefits include the reduction of osteoporosis by suppressing osteoclasts and lymphocyte functions, decreased the risk of cardiovascular attacks and relieved postmenopausal problems. Genistein traditionally used in Chinese and Ayurvedic medicine and are found to be associated with lower risk of breast, prostate and lung cancer. Numerous factors comprising genetic, epigenetic and transcriptomic alterations are evidenced to be responsible for breast, prostate and lung cancer. In present review, an overview on genistein, the various analytical methods and drug delivery approaches to determine genistein in the formulations are discussed. It may help to develop novel formulations with better solubility and bioavailability of genistein. The tumor cell scan may be targeted to form a stable genistein formulation.
Der Mini-Audio-Test (MAT) – eine Screeningmethode auf
Schwerhörigkeit für Haus- und Fachärzte
Authors: Löhler Jan , Lehmann Martin , Segler Veronika , Volkenstein Stefan , Battmer Rolf-Dieter , Ernst Arneborg , Gräbner Frederike , Schlattmann Peter , Schönweiler Rainer , Wollenberg Barbara , Dazert Stefan
Published: December 2018

Hintergrund In Deutschland leiden etwa 15 Millionen Menschen an einer
Schwerhörigkeit (SH), doch nur 16 % tragen Hörgeräte. Diese Unterversorgung kann
für die Betroffenen zu schwerwiegenden Folgen (soziale Isolation, Depression,
Förderung einer Demenz etc.) führen. Ein frühzeitiges und flächendeckendes
Hörscreening ab dem 50. Lebensjahr kann dies verbessern. In dieser Studie wurde
der Mini-Audio-Test (MAT), ein sechs Fragen zum subjektiven Hörverlust (HV)
umfassender Test mit dreistufiger Antwortskala, an einem Normalkollektiv
überprüft (Sensitivität (Se), Spezifität (Sp), positiver prädiktiver Wert
(PPW)).

Methode Es wurden 943 Patienten (älter als 50 Jahre) ohne bekannte
Ohrenerkrankungen mittels MAT befragt, zum Vergleich die Hörschwellen
tonaudiometrisch ermittelt und die Se, Sp und der PPW zur Detektion eines
relevanten HV durch den MAT für die Altersklassen < 60 Jahre (AG1) und ≥ 60
Jahre (AG2) mittels binomialer Proportionen ermittelt.

Ergebnisse Die Se lag für AG1 bei 0,66, die Sp bei 0,61, der PW bei 0,60,
für die AG2 lag die Se bei 0,47, die Sp bei 0,80, der PPW bei 0,89.

Schlussfolgerung Entsprechend der vorliegenden Ergebnisse wird der Einsatz
des MAT als Screeningmethode für Nicht-HNO-Ärzte zur Detektion von
schwerhörenden Patienten ab dem 50. Lebensjahr vorgeschlagen. Hierdurch ließen
sich auch schwerwiegende Begleiterkrankungen wie Minderung der kognitiven
Leistungsfähigkeit, Sturzrisiko, Depression und Demenz positiv beeinflussen.
Tunability and enlargement of omnidirectional transmission frequency range in a photonic heterostructure containing Dirac semimetal
Authors: Zhao Yunkun , Zhang Yuping , Cao Maoyong , Zhang Huiyun
Published: December 2018

In this study, We theoretically realized the enlargement of the photonic crystal band gap by a photonic heterostructure containing Dirac semimetal layer. At the same time, since the dielectric constant of the Dirac semimetal changes with its Fermi level, based on this characteristic, we have realized the adjustment of the band gap of the enlarged photonic crystal. Comparing a single photonic crystal with a heterostructure photonic crystal, it is found that the photonic band gap of the heterostructure photonic crystal is significantly enlarged, and then the effects of different incident angles and polarized waves on the photonic band gap are analyzed. Based on the above properties, it has potential applications in tunable photonic crystal devices.
Analysis of temperature dependent electrical performance of Al/CuO/ITO Schottky barrier diode and explanation of inhomogeneous barrier heights by double Gaussian distribution
Authors: Jana Rajkumar , Sil Sayantan , Dey Arka , Datta Joydeep , Ray Partha Pratim
Published: December 2018

Here temperature dependent electrical properties of two differently synthesized CuO nanoparticles (hydrothermal (CuO (H)) and reflux (CuO (R))) based Schottky barrier diodes (SBDs) have been investigated. Both the materials based devices show an abnormal decrease in the ideality factor (η) and an increase in the barrier height (BH) with the increase in temperature. Experimentally obtained Richardson constant (A*) for both materials based devices show much lower values than the theoretical values. This discrepancy in A* due to the presence of inhomogeneities at the barrier height (BH) of metal-semiconductor (MS) interface has been analyzed by assuming double Gaussian distribution (GD) of the BHs.The mean BH values (ϕb0¯) for CuO (H) based devices obtained as 1.18eV and 1.07eV with standard deviation 0.18V and 0.15 V respectively which are less than the values of its counterpart. The obtained values of A* from the modified plot for both SBDs are in close agreement with the theoretical values. This study portrays a successful explanation of temperature dependent current-voltage characteristics of these two SBDs assuming double GD of the BHs.
Spin-orbit torques acting upon a perpendicularly magnetized Py layer
Authors: Chen Tian-Yue , Ou Yongxi , Tsai Tsung-Yu , Buhrman R. A. , Pai Chi-Feng
Published: December 2018

We show that Py, a commonly used soft ferromagnetic material with weak anisotropy, can become perpendicularly magnetized while depositing on a Ta buffer layer with Hf or Zr insertion layers (ILs) and an MgO capping layer. By using two different approaches, namely, harmonic voltage measurement and hysteresis loop shift measurement, the dampinglike spin-orbit torque (DL-SOT) efficiencies from Ta/IL/Py/IL/MgO magnetic heterostructures with perpendicular magnetic anisotropy are characterized. We find that though Ta has a significant spin Hall effect, the DL-SOT efficiencies are small in systems with the Ta/Py interface compared to that obtained from the control sample with the traditional Ta/CoFeB interface. Our results indicate that the spin transparency for the Ta/Py interface is much less than that for the Ta/CoFeB interface, which might be related to the variation of spin mixing conductance for different interfaces.
A meta-analysis comparing four measurement methods to determine the relationship between methane emissions and dry-matter intake in New Zealand dairy cattle
Authors: Jonker Arjan , Green Peter , Waghorn Garry , van der Weerden Tony , Pacheco David , de Klein Cecile
Published: December 2018

Enteric methane (CH4) emissions and dry-matter intake (DMI) can be accurately and precisely measured in respiration chambers (RC), whereas automated head chambers (GreenFeed; GF) and the SF6 tracer method can provide estimates of CH4 emissions from grazing cattle. In New Zealand, most dairy cattle graze pasture and, under these conditions, DMI also has to be estimated. The objective of the current study was to compare the relationship between CH4 production and DMI of New Zealand dairy cattle fed forages using the following four measurement methods: RC with measured DMI (RC); sulfur hexafluoride (SF6) with measured DMI (SF6-DMI); SF6 with DMI estimated from prediction equations or indigestible markers (SF6); GF with measured or estimated DMI (GF). Data were collected from published literature from New Zealand trials with growing and lactating dairy cattle fed forage-based diets and data were analysed using a mixed-effect model. The intercept of the linear regression between CH4 production and DMI was not significantly different from zero and was omitted from the model. However, residual variance (observed–predicted values) increased with an increasing DMI, which was addressed by log-transforming CH4 per unit of DMI and this model was used for final data analysis. The accuracy of the four methods for predicting log CH4 per unit of DMI was similar (P = 0.55), but the precision (indicated by residuals) differed (P < 0.001) among methods. The residual standard deviations for SF6, GF and SF6-DMI were 4.6, 3.4 and 2.1 times greater than the residuals for RC. Hence, all methods enabled accurate prediction of CH4 per unit of DMI, but methodology for determining both CH4 and DMI affected their precision (residuals).
Uniform bounds for solutions to elliptic problems on simply connected planar domains
Authors: Battaglia Luca
Published: December 2018

We consider the following elliptic problems on simply connected planar domains:
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\begin{equation*} \left \{\begin {array}{ll}-\Delta u=\lambda |x|^{2\alpha }K(x)e^u&\text {in }\Omega \\u=0&\text {on }\partial \Omega \end{array}\right . ;\quad \quad \left \{\begin {array}{ll}-\Delta u=|x|^{2\alpha }K(x)u^p&\text {in }\Omega \\u>0&\text {in }\Omega \\u=0&\text {on }\partial \Omega \end{array}\right . \end{equation*}

with
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="alpha greater-than negative 1 comma lamda greater-than 0 comma p greater-than 1 comma 0 greater-than upper K left-parenthesis x right-parenthesis element-of upper C Superscript 1 Baseline left-parenthesis normal upper Omega overbar right-parenthesis">

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\alpha >-1,\lambda >0,p>1,0>K(x)\in C^1\left (\overline \Omega \right )

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We show that any solution to each problem must satisfy a uniform bound on the mass, which is given, respectively, by

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. The same results apply to some systems and more general nonlinearities.

The proofs are based on the Riemann mapping theorem and a Pohožaev-type identity.
In silico error correction improves cfDNA mutation calling
Authors: Kim Chang Sik , Mohan Sumitra , Ayub Mahmood , Rothwell Dominic G , Dive Caroline , Brady Ged , Miller Crispin
Published: December 2018

Motivation

Circulating-free DNA (cfDNA) profiling by sequencing is an important minimally invasive protocol for monitoring the mutation profile of solid tumours in cancer patients. Since the concentration of available cfDNA is limited, sample library generation relies on multiple rounds of PCR amplification, during which the accumulation of errors results in reduced sensitivity and lower accuracy.

Results

We present PCR Error Correction (PEC), an algorithm to identify and correct errors in short read sequencing data. It exploits the redundancy that arises from multiple rounds of PCR amplification. PEC is particularly well suited to applications such as single-cell sequencing and circulating tumour DNA (ctDNA) analysis, in which many cycles of PCR are used to generate sufficient DNA for sequencing from small amounts of starting material. When applied to ctDNA analysis, PEC significantly improves mutation calling accuracy, achieving similar levels of performance to more complex strategies that require additional protocol steps and access to calibration DNA datasets.

Availability and implementation

PEC is available under the GPL-v3 Open Source licence, and is freely available from: https://github.com/CRUKMI-ComputationalBiology/PCR_Error_Correction.git.

Supplementary information

Supplementary data are available at Bioinformatics online.
Accurate and efficient estimation of smallP-values with the cross-entropy method: applications in genomic data analysis
Authors: Shi Yang , Wang Mengqiao , Shi Weiping , Lee Ji-Hyun , Kang Huining , Jiang Hui
Published: December 2018

Motivation

Small P-values are often required to be accurately estimated in large-scale genomic studies for the adjustment of multiple hypothesis tests and the ranking of genomic features based on their statistical significance. For those complicated test statistics whose cumulative distribution functions are analytically intractable, existing methods usually do not work well with small P-values due to lack of accuracy or computational restrictions. We propose a general approach for accurately and efficiently estimating small P-values for a broad range of complicated test statistics based on the principle of the cross-entropy method and Markov chain Monte Carlo sampling techniques.

Results

We evaluate the performance of the proposed algorithm through simulations and demonstrate its application to three real-world examples in genomic studies. The results show that our approach can accurately evaluate small to extremely small P-values (e.g. 10-6 to 10-100). The proposed algorithm is helpful for the improvement of some existing test procedures and the development of new test procedures in genomic studies.

Availability and implementation

R programs for implementing the algorithm and reproducing the results are available at: https://github.com/shilab2017/MCMC-CE-codes.

Supplementary information

Supplementary data are available at Bioinformatics online.
Capsule network for protein post-translational modification site prediction
Authors: Wang Duolin , Liang Yanchun , Xu Dong
Published: December 2018

Motivation

Computational methods for protein post-translational modification (PTM) site prediction provide a useful approach for studying protein functions. The prediction accuracy of the existing methods has significant room for improvement. A recent deep-learning architecture, Capsule Network (CapsNet), which can characterize the internal hierarchical representation of input data, presents a great opportunity to solve this problem, especially using small training data.

Results

We proposed a CapsNet for predicting protein PTM sites, including phosphorylation, N-linked glycosylation, N6-acetyllysine, methyl-arginine, S-palmitoyl-cysteine, pyrrolidone-carboxylic-acid and SUMOylation sites. The CapsNet outperformed the baseline convolutional neural network architecture MusiteDeep and other well-known tools in most cases and provided promising results for practical use, especially in learning from small training data. The capsule length also gives an accurate estimate for the confidence of the PTM prediction. We further demonstrated that the internal capsule features could be trained as a motif detector of phosphorylation sites when no kinase-specific phosphorylation labels were provided. In addition, CapsNet generates robust representations that have strong discriminant power in distinguishing kinase substrates from different kinase families. Our study sheds some light on the recognition mechanism of PTMs and applications of CapsNet on other bioinformatic problems.

Availability and implementation

The codes are free to download from https://github.com/duolinwang/CapsNet_PTM.

Supplementary information

Supplementary data are available at Bioinformatics online.
New models of atherosclerosis and multi-drug therapeutic interventions
Authors: Parton Andrew , McGilligan Victoria , Chemaly Melody , O’Kane Maurice , Watterson Steven
Published: December 2018

Motivation

Atherosclerosis is amongst the leading causes of death globally. However, it is challenging to study in vivo or in vitro and no detailed, openly-available computational models exist. Clinical studies hint that pharmaceutical therapy may be possible. Here, we develop the first detailed, computational model of atherosclerosis and use it to develop multi-drug therapeutic hypotheses.

Results

We assembled a network describing atheroma development from the literature. Maps and mathematical models were produced using the Systems Biology Graphical Notation and Systems Biology Markup Language, respectively. The model was constrained against clinical and laboratory data. We identified five drugs that together potentially reverse advanced atheroma formation.

Availability and implementation

The map is available in the Supplementary Material in SBGN-ML format. The model is available in the Supplementary Material and from BioModels, a repository of SBML models, containing CellDesigner markup.

Supplementary information

Supplementary data are available at Bioinformatics online.
7-hydroxyfrullanolide, isolated from Sphaeranthus indicus, inhibits colorectal cancer cell growth by p53-dependent and -independent mechanism
Authors: Pandey Praveen , Singh Deepika , Hasanain Mohammad , Ashraf Raghib , Maheshwari Mayank , Choyal Kuldeep , Singh Akhilesh , Datta Dipak , Kumar Brijesh , Sarkar Jayanta
Published: December 2018

Sphaeranthus indicus Linn. is commonly used in Indian traditional medicine for management of multiple pathological conditions. However, there are limited studies on anticancer activity of this plant and its underlying molecular mechanisms. Here, we isolated an active constituent, 7-hydroxyfrullanolide (7-HF), from the flowers of this plant, which showed promising chemotherapeutic potential. The compound was more effective in inhibiting in vitro proliferation of colon cancers cells through G2/M phase arrest than other cancer cell lines that were used in this study. Consistent with in vitro data, 7-HF caused substantial regression of tumour volume in a syngeneic mouse model of colon cancer. The molecule triggered extrinsic apoptotic pathway, which was evident as upregulation of DR4 and DR5 expression as well as induction of their downstream effector molecules (FADD, Caspase-8). Concurrent activation of intrinsic pathway was demonstrated with loss of ΔΨm to release pro-apoptotic cytochrome c from mitochondria and activation of downstream caspase cascades (Caspase -9, -3). Loss of p53 resulted in decreased sensitivity of cells towards pro-apoptotic effect of 7-HF with increased number of viable cells indicating p53-dependent arrest of cancer cell growth. This notion was further supported with 7-HF-mediated elevation of endogenous p53 level, decreased expression of MDM2 and transcriptional upregulation of p53 target genes in apoptotic pathway. However, 7-HF was equally effective in preventing progression of HCT116 p53+/+ and p53−/− cell derived xenografts in nude mice, which suggests that differences in p53 status may not influence its in vivo efficacy. Taken together, our results support 7-HF as a potential chemotherapeutic agent and provided a new mechanistic insight into its anticancer activity.
Hemispheric Module-Specific Influence of the X Chromosome on White Matter Connectivity: Evidence from Girls with Turner Syndrome
Authors: Zhao Chenxi , Yang Liyuan , Xie Sheng , Zhang Zhixin , Pan Hui , Gong Gaolang
Published: December 2018

Turner syndrome (TS) is caused by the congenital absence of all or part of one of the X chromosomes in females, offering a valuable human “knockout model” to study the functioning patterns of the X chromosome in the human brain. Little is known about whether and how the loss of the X chromosome influences the brain structural wiring patterns in human. We acquired a multimodal MRI dataset and cognitive assessments from 22 girls with TS and 21 age-matched control girls to address these questions. Hemispheric white matter (WM) networks and modules were derived using refined diffusion MRI tractography. Statistical comparisons revealed a reduced topological efficiency of both hemispheric networks and bilateral parietal modules in TS girls. Specifically, the efficiency of right parietal module significantly mediated the effect of the X chromosome on working memory performance, indicating that X chromosome loss impairs working memory performance by disrupting this module. Additionally, TS girls showed structural and functional connectivity decoupling across specific within- and between-modular connections, predominantly in the right hemisphere. These findings provide novel insights into the functional pathways in the brain that are regulated by the X chromosome and highlight a module-specific genetic contribution to WM connectivity in the human brain.