bluuebunny/crossref_metadata_2025 huggingface dataset:
Steady and Unsteady RANS Modeling of Wake Effects and Grid Resolution Requirements in a Low-Pressure Turbine Cascade
Authors: Führing Alexander , Kožulovic Dragan , Bode Christoph , Franke Matthias
Published: January 2021

Due to relative motion between rotors and stators in aircraft engines, periodic wakes are present in downstream blade rows, which exert significant influence at flow loss and engine efficiency. To quantify and reproduce this influence, a low-pressure turbine cascade is computed using steady and unsteady RANS methods in the flow solver TRACE by DLR and MTU Aero Engines. A thorough grid study is carried out and various aspects of grid resolution requirements are investigated for the setups and considered performance metrics respectively. A steady state transition model extension that has been developed and published by the authors is applied to the cascade flow at a number of operating points and validated with experimental data while being compared to the unsteady results as well as the steady state results without the wake effect extension. Further, a variation of wake-related parameters is carried out while discussing the effects modeled in the unsteady setup as well as the ability of the two steady state setups (with and without wake extension) to capture the trends identified by the unsteady results. A sufficiently accurate reproduction by the wake model extension enables steady simulations of the inherently unsteady effects in the aerodynamic design of the turbine, which results in an enormous saving of computational time and effort.
Development of a Cargo Airdrop Modeling Method for a Tactical Blended-Wing-Body UAV
Authors: Mitridis D. , Mathioudakis N. , Panagiotou P. , Yakinthos K.
Published: January 2021

In this paper, the development of a cargo airdrop modeling method is presented for a fixed-wing tactical UAV. The UAV, which is being developed in the framework of the DELAER UAS project, is based on the Blended-Wing-Body layout, and its mission is to deliver cargo and lifesaving supplies via airdrop, to remote and isolated Greek territories as well as over isolated islands in the Aegean Sea. At first, a simplified kinematic model is developed, to describe the trajectory of the cargo. Then, the critical airdrop parameters, such as the aerodynamic drag and the effect of wind gusts, are identified and incorporated to the model. Based on this model, an analysis methodology is proposed, conducted in several simulation loops. In each simulation loop, the cargo mass, release height, drop velocity and wind gust speed are the main variables. The results are given in a form of scatter plots, depicting the simulated cargo airdrop positions on the ground (or sea), around an actual target location, with respect to the drop height, drop velocity and wing magnitude. A solid conclusion is that, by releasing the cargo box with tailwind, the accuracy of the airdrop can be improved as much as 67% compared to any other wind direction.
A CSM-CFD methodology applied to the design of a cryogenic WT model
Authors: Russo S , Kirchner J. , Seiler J. , Graumann G , Adden S , Paletta N
Published: January 2021

The Aero-structural coupled analysis presented in this work represents an important part of the PRODIGE project, whose main purpose is the prediction of aerodynamics and hinge moment loads of the aileron of a scale model of business jet at transonic Mach numbers and flight Reynolds number. More in details, this methodology supports the design activities of the cryogenic wind-tunnel (WT) model to be tested in the European Transonic Wind tunnel (ETW). The need to implement such a kind of analysis comes from the requirement to take into account the “pure aeroelastic effect” during experimental tests and need to understand the effect of the WT model flexibility on the control surface load prediction, prior to and in parallel with the balance design. CFD evaluations are performed on the whole model, while a static Fluid-Structure-Interface (FSI) procedure is set up and, only, applied to the wing and aileron of the model. The FSI cycle is made of two blocks: a CFD evaluation part and a CSM evaluation part. Both modules are coupled within an iterative loop, where information are exchanged between them. Two angles of incidence are taken into account, i.e. the lowest value (α=-3°) and the highest one (α=6°). Results will be compared in terms of global aerodynamic forces and pressure coefficient distributions. Moreover the new deformed shapes derived from the application of both approaches will be compared with the original one.
Reliable method of aerodynamic analysis using computational fluid dynamics and scaled models in the development process of a Very Light Airplane
Authors: Olejnik Aleksander , Dziubmski Adam , Kiszkowiak Lukasz
Published: January 2021

In past decades a massive improvement of computational fluid dynamics (CFD) methods and the rapid increase of computational resources made it possible to simulate a lot of phenomena appearing during the flow of fluid around objects. In following paper a reliable method of aerodynamic analysis using both CFD and scaled models in the development process of a Very Light Airplane have been presented. A method of preparing a numerical model of an airplane and the aerodynamic analysis methodology have been shown. A numerical calculations using finite volume method implemented in specialized software were performed. What is more important, to perform the aerodynamic tests in wind tunnels, scaled models of an airplane have been prepared using the modern and fast manufacturing technologies, including 3D printing and CNC machining. The results have been shown in the graphs form of aerodynamic force and moment components as function of angle of attack. During research an influence of structural parts of an airplane on aerodynamic characteristics have been analyzed. The qualitative results of a flow around the aircraft body have been presented in form of parameter distribution maps on the airframe surface have been shown. Visualization of pressure distribution have been extended with path lines visualization of the flow. The research described in the paper is an example of professional and innovative approach to the subject matter.
Generative design case study of a CNC machined nose landing gear for an unmanned aerial vehicle
Authors: Zaimis I , Giannakis E , Savaidis G
Published: January 2021

Generative design is a design method inspired by nature’s evolution, pushing the limits of the industry to new design solutions. Using minimum input requirements, the resulting designs can be structurally adequate, weight-optimised and almost production-ready. The main purpose of this paper is to present the different approaches of the standard engineering design and the generative design methods. This is achieved through the case study of a nose landing gear for a prototype tactical unmanned aerial vehicle, intended for low volume production. The first part of the paper outlines the conceptual design of the nose landing gear. Subsequently, during the preliminary phase, the stress distribution along the different parts is calculated, based on the classic Strength of Materials theory and therefore a design solution is produced. In the second part, a generative design study is carried out with a commercially available tool, based on the conceptual parameters previously chosen. Both concepts are studied with industry-standard finite element analysis tools in order to validate, from a theoretical standpoint, the strength requirements according to the STANAG 4671 regulation. The final structure will be manufactured with 3-axis CNC machining, while providing about 36% weight reduction without compromising the structural functionality.
An overview of the new research infrastructure for rotating labyrinth seals at COMOTI
Authors: Gherman B , Flore L , Carlanescu R , Enache M S , Anghel O , Radu A G
Published: January 2021

In this article will be described the improved test stand for rotating labyrinth seals that will be developed at COMOTI. The present test rig is able to test only a seal configuration in a simplified environment, (air temperature max.150° C, labyrinth diameter max. 300 mm, airflow rate max. 0.35 kg/s, pressure max. 9 bars). The newly improved research infrastructure will be able to increase these limits up to: 800°C temperature, 600 mm labyrinth diameter, 10 kg/s airflow rate and 50 bars pressure. The upgrade performed on to this research facility will comprise of a test rig for experimental measurements; a air supply station with two centrifugal compressors; an air cooling tower; a air tank to store high pressure air and an air heater station capable to supply air with 800°C.
Development of top-level requirements for regional aircraft based on the needs of the Russian market
Authors: Karpov A.E. , Nesterenko B.G. , Ovdienko M.A. , Varyukhin A.N. , Vlasov A.V
Published: January 2021

The share of regional flight traffic is estimated as 10% of all air transport network in Russian Federation. According to the federal plans on infrastructure improvement, the regional aviation in Russia should provide public transport accessibility of remote areas. Thus the actual task is to provide economically efficient aircraft for local airliners in one hand, and to satisfy the upcoming regulations on ecology standards. One of the solutions is seen in development of regional aircraft with hybrid electric power engine. The paper includes the analysis of current state and trends of the interregional air transport system of Russia for the period 2030 – 2035. It gives, in addition, a composition and a volume of commercial traffic performed by the regional fleet. Also, some results of operational requirements assessment and the analysis of technical excellence of commercial regional aircrafts are presented. The assessment of the environmental requirements for this class of aircraft was carried out on the basis of ICAO standards.
Power control system for lightweight electric aircraft
Authors: Zagumennov F A , Varyukhin A N , Kazakov A V , Zhuravlev D I , Zakharchenko V S , Ivanov G.S.
Published: January 2021

This article describes the development and key features of the lightweight electric aircraft power system. The overview includes internals of main power control units and propulsion system rigging, hardware parts selection guide and fail-safe features in hardware and software of aircraft. The propulsion system includes lightweight solution utilizing brushless DC (BLDC) motor with a propeller as the main thrust generator, and a control system, which consists of insulated gate bipolar transistors (IGBT) 3-phase bridge and control system, as well as a special optical-insulated throttle controller. Main power control system automatically starts up aircraft modules and provides all the necessary information coming from the sensors. All of the key components in aircraft are connected through Controller Area Network (CAN) interface. To create a strong protection against surges and electric interference special cabling and interfacing aspects between several systems of lightweight aircraft are described. Part of the article provides a future extendibility, versatility and economical concepts.
Numerical Methodology for Aerostructures Hail Impact Damage Prediction
Authors: Ivancevic D. , Zakan I.Badurina , Smojver I.
Published: January 2021

The two numerical approaches for modelling of soft-body impact in Abaqus/Explicit have been applied in this work for prediction of high-velocity hail impact damage in aeronautical structures. The applied methods are the CEL (Coupled Eulerian Lagrangian) and SPH (Smoothed Particle Hydrodynamics), while the impacted structure is a metallic slat structure. Comparison of the CEL and SPH methods has been performed by impact simulations at a rigid plate, aimed to validate the applied material model, and by simulation of the slat structure impact. Two material models have been applied to study the effect of high strain-rates at the damage process in the metallic structure. The first is the standard isotropic plasticity model that defines material failure based on the value of equivalent plastic strain. The second constitutive model in the analyses is the Johnson-Cook model that includes the effects of strain rate and temperature on the material failure process. The simulations have been stable, illustrating the robustness of Abaqus/Explicit in these highly nonlinear impact cases. Compared to the CEL, the SPH method is computationally more efficient.
Sloshing induced damping in vertically vibrating systems
Authors: De Courcy J J , Constantin L , Titurus B , Rendall T C S , Cooper J E
Published: January 2021

All aircraft are subject to a range of loading throughout ground and flight operations, which ultimately define the sizing and weight of the aircraft structure. Active and passive loads alleviation technologies provide an approach to reduce dynamic loads arising from atmospheric gusts and turbulence, leading to more fuel-efficient aircraft designs. Within the H2020 SLOWD project, fuel sloshing is being considered as a method for alleviating loads in aircraft wings via an increase in effective damping. Recent work has considered the transient response of a vertically vibrating, single degree of freedom system coupled to a rectangular liquid-filled tank. This research revealed identifiable dissipation regions in the free vibration responses characterised by their own distinct equivalent damping ratio values. In this work, free surface displacement has been extracted from high-speed camera footage during the chosen sloshing regimes, which are representative of a decaying parametrically excited fluid. These results are compared against a fluid-structure coupled numerical model based upon smoothed particle hydrodynamics, previously shown to have good agreement with the experimental damping response. Further analysis of the free-surface response of the numerical solution notes a presence of an undesired travelling longitudinal wave. The analysis of this discrepancy between the model and experiment is then used to improve the numerical formulation, showing a requirement for modelling surface tension.
A concept for an Integrated Mission Management System for Small Air Transport vehicles in the COAST project
Authors: Di Vito V , Grzybowski P , Rogalski T , Maslowski P
Published: January 2021

Small Air Transport (SAT) is emerging as suitable transportation means to allow efficient travel over a regional range, in particular for commuters, based on the use of small airports and fixed-wing aircraft with 5 to 19 seats, belonging to the EASA CS-23 category. In this framework, Clean Sky 2 Joint Undertaking, in the European Union’s Horizon 2020 research and innovation program, funded the project COAST (Cost Optimized Avionics SysTem), which started in 2016 with the aim of delivering key technology enablers for the affordable cockpit and avionics, while also enabling single-pilot operations for aircraft in the SAT domain. In the project, some relevant flight management technologies to support single-pilot operations are considered, namely the ones of tactical traffic separation and enhanced situational awareness, meteorological enhanced awareness, and pilot’s incapacitation emergency management. These technologies have been subject to a dedicated design and implementation process, based on an individual approach where each of them has been considered as independent and dedicated single-pilot operations enabling technology. Nevertheless, during the project execution, it emerged the opportunity to consider proper integration and enhancement of such technologies to design a unique Integrated Mission Management System (IMMS). Such IMMS technology has been considered as a potential solution to support the more effective and safe management of situations of pilot’s incapacitation during the flight, under single-pilot operations, and as a relevant step forward towards more autonomous aircraft. Based on these considerations, Clean Sky supported and funded proper extension of the COAST project scope, to include the design of the additional Integrated Mission Management System. This paper, therefore, aims to outline the main concepts implemented by the baseline individual technologies (Flight Reconfiguration System, Tactical Separation System, and Advanced Weather Awareness System) already considered in the COAST project and representing the basic building blocks towards IMMS and, after that, aims to introduce the IMMS motivations and opportunities. Furthermore, the paper describes the main functionalities expected to be implemented by the Integrated Mission Management System and, finally, the expected design and implementation process.
Building Digital Transformation to improve NGCTR design and simulation
Authors: Sesana Michele , Bardelli Alessandro Pietro
Published: January 2021

new technologies and increasing accessibility of powerful hardware are opening a new world of opportunity to digitalize current processes making them more efficient. The paper will discuss the process of digital transformation of the NGCTR flight test campaign in which the new big data analysis technologies have a central role in the gathering, storing analyses and provision of evidence about what happened during flight. The new approach is enabled thanks to a powerful big data analysis cluster which have been tailored to best support the specific process.
Methodologies for the initial design studies of an innovative community-friendly miniliner
Authors: Trainelli Lorenzo , Riboldi Carlo E.D. , Rolando Alberto , Salucci Francesco
Published: January 2021

The present paper illustrates some of the strategies adopted to set the top-level aircraft requirements for an innovative near-zero emission miniliner. This novel 19-seater is conceived to provide a micro-feeder service, devised to exploit the existing European network of small local airports and airfields as feeders to hubs, as well as an intercity service to enhance connections between destinations that are not served by efficient ground transportation. First, a survey of the current network of airports and airfields is carried out and the existing ground transportation is analysed. Secondly, the potential demand for the microfeeder and intercity services is estimated based on the assessment of the time advantage between ground based means of transport and the miniliner option. Application examples in different geographic contexts provide useful information for the definition of crucial design requirements such as payload, range, runway length, and cruising airspeed.
Smart energy systems and smart metering systems in them
Authors: Zatsarinnaya Yu N , Grigoreva M O
Published: January 2021

The authors of the article evaluated the level of digitalization and the achieved effects during using digital technologies by means of the digitalization index at present and its predicted values. Tools were given to support and stimulate prosumers as active participants in smart energy s3ystems. The integration into the power supply system of 2 prosumers is considered – a logging plant and a shopping center. Their consumption of electricity from the network is analyzed in the case when the generation of electricity from its own sources is insufficient from 2018-2019. The calculations were carried out in several price categories. The calculations showed that in the conditions of accurate planning, in the absence of emergency situations, prosumers who are legal entities can save. To switch to these calculations, it is necessary to install metering devices that allow you to measure hourly consumption. Thus, the smart energy system allows the consumer to choose a price category that suits him based on the energy consumption data of previous months.
Virtual simulator of a boiler room
Authors: Kocharyan E V , Shaposhnikov V V , Macharashvili A S
Published: January 2021

The use of virtual simulators, computer models of equipment and production processes, is already a necessity in the modern world. Teachers of KubSTU have developed and tested a virtual simulator of a hot-water boiler for theoretical training and development of skills in the work of both future and current thermal power engineers. This simulator is not only an effective learning tool but also the basis for creating a remote control system for a complex production facility, which is a boiler room.
The main problems and solutions to the management of the electric power system by the example of metropolis power supply
Authors: Chemborisova N Sh , Pogorelets M Yu
Published: January 2021

Developments of electric power systems of Russia as well as foreign electric power systems are on the way of the annual complications. This trend can be well observed in the example of the development of electric power systems of large agglomerations - metropolises. We should also mention that along with this complication new labor-intensive tasks arise - increasing the reliability, improving the management of modes and ensuring the survivability of electric power systems, in this regard, we can distinguish the following factors:

• increasing the number of interconnected power facilities;

• growth of the maximum installed capacity of the power system;

• complication of the electrical network;

• complication of ensuring the required level of controllability of objects;

• increasing of short circuit currents.

Thus, designers of electric power systems often use the principle of multi-factority in their design, which ultimately just affects the complexity of electric power systems, leading to a large number of configurations of network circuits that have different capabilities, properties, technical and economic indicators.
Influence of light on electrophysical properties of thin films of mixed zinc and tin oxides
Authors: Petrov V V , Bayan E M , Varzarev Yu N , Volkova M G , Storozhenko V Yu , Rozhko A A , Nesterenko A V
Published: January 2021

In this work, we studied structural and the electrical properties of thin films of mixed zinc and tin oxides obtained by low-temperature pyrolysis. XRD analysis shows that the obtained films contain phases of zinc oxide and tin dioxide and have nanocrystalline structure with crystallite size about 10-17 nm. A significant effect of daylight on the temperature dependences of the film resistance was established. The temperature dependences of the resistance of ZnO-SnO2 films, measured in the range from room temperature to 300 °C, show the difference between the heating and cooling curves, that can be explained by two competing processes - thermal activation mechanism of conductivity and adsorption-desorption of oxygen particles on the surface of the oxide film. Using the slope of the linear section on the plots, we calculated the activation energy of conductivity, which amount is 0.7 and 1.1 eV for the samples with the different Zn:Sn ratio.
Vertical axis wind power plant
Authors: Belyakov P Yu , Pisarevsky Yu V , Tikunov A V , Pisarevsky A Yu , Chernykh T E
Published: January 2021

The issue of developing technologies using alternative renewable energy sources today is a very urgent task both around the world and in Russia, which is explained by economic, technological, and, most importantly, environmental factors. The climatic and geo-graphical features of our country create all the necessary conditions for the use of such areas as solar energy, small hydro energy, wind energy, etc. But the most promising in terms of energy potential is wind energy, as many regions of our country are located in areas with high average wind speeds. However, there are a number of problems that impede the development of wind energy in Russia, the most important of which is the almost complete absence of wind generators designed and manufactured in our country that could compete with foreign models. The product proposed in the article is an attempt to solve this problem through the use of a new design of a wind wheel and an electric generator, as well as the use of magnetic suspensions.
Digital control of structurally unstable power facilities using a polynomial approach
Authors: Zakhvatov V I , Podvalny S L , Mikhailusov A V
Published: January 2021

The problem of improving the quality of control of structurally unstable power facilities is viewed based on a polynomial controller with a dynamic change in settings using the inverse pendulum on a carriage as an example. The mathematical model of the control object was built; a polynomial controller was synthesized using the method of symbolic computation of systems of differential equations with an additional input for specifying the geometric mean root from the outside. Reverse pendulum model on a carriage and a model of regulators were created using the MATLAB Simulink visual modeling environment to analyze the quality and parameters of the created control system. As a result of modeling, direct dependence of the position setting time of pendulum on the value of the geometric mean root was obtained which confirmed the possibility of external control of the speed of the control system. The possibility to control the control actions level to prevent saturation of executive devices was investigated and confirmed. In fact, a system of external parametric control of the processes dynamics was created and the described regulator does not require adaptation and training.
Intelligent identification of telecommunication channels in the distributed systems for digital control of power facilities
Authors: Podvalny S L , Likhotin M A
Published: January 2021

This paper presents the results and problems of telecommunication power amplifier modeling. The research tool is the mathematical apparatus of artificial neural networks. Simulation of the device was made according to the black box principle, operating solely with input and output data of the power amplifier under study. The criterion for the quality of model estimation was the signal-to-noise ratio adopted in radio engineering. Brief results of the previous research are shown. The problems associated with the simulation of a power amplifier operation basing on neural networks were investigated. An example is given of nonlinear distortions appearing in the device under consideration. The description is given of the joint work of a neural networks group based on analog signal clustering which works according to the principle of Grossberg’s adaptive resonance theory. The application results of this type of systems are shown. Discussing the problems concerning the use of this approach to simulation of the investigated processes.
Complex engineering object digital twins – power engineering smart transformation basic concept
Authors: Zhabitskii M G , Melnikov V E , Boyko O V
Published: January 2021

The formation of information models and digital twins is a general element of the modern description of complex engineering objects. Their presence is already becoming a requirement of national and international technical regulation and contractual relations. The stage of forming separate digital twins within different stages of the life cycle has been passed and the approach has proven to be effective and in demand. The most striking example is BIM technologies. Now it is important to switch to complex end-to-end information models and digital twins for the full life cycle of complex engineering objects. This innovation becomes a universal tool for the interaction of all stakeholders in high-tech industries. Competence in technologies for working with complex information models and digital twins on the full life cycle of complex engineering objects is already a key competitive factor for high-tech engineering and operating companies in power production. This is a proactive trend in the formation of intellectual energy data space. It will lead to another cycle of improving the efficiency, safety, and economy of the industry and businesses.
Low-light phase imaging using in-line digital holography and the transport of intensity equation
Authors: Gupta Alok K , Nishchal Naveen K
Published: January 2021

In one of our recent studies, we have shown that a large defocusing distance in the transport of intensity equation (TIE) is required to retrieve the phase information in low-light conditions (OSA Continuum 3 (2020) 236). It has been found that image misalignment issues come into the picture due to translation of the camera for large distances, which creates artifacts in phase recovery. The issue of misalignment can be overcome if, instead of the object, we use the digital hologram of the object for the required defocused intensities and then apply the TIE. In this paper, we demonstrate low-light phase imaging by combining digital holography with the TIE. We reconstruct the required multiple intensity distributions from the captured in-line digital hologram. To implement the low-level light illumination, a variable neutral density filter has been used while recording the in-line digital hologram. Simulation and experimental results with different objects (United States air-force chart and glue drop) are presented. To simulate the low-light conditions, a Poisson distribution based photon-counting imaging technique has been applied.
The breakdown of Moore’s law induced by weak Anderson localization and by size effects in nano-scale metallic connectors
Authors: Arenas Claudio , Herrera Guillermo , Muñoz Enrique , Munoz Raul C
Published: January 2021

We report the resistivity measured at temperatures between 5 K and 300 K of a Cu film 63 nm thick with grains that have a diameter d = 10.5 nm on the average. The resistivity of this film is described by the first quantum theory of resistivity of nano-scale metallic connectors [R C Munoz et al, App. Phys. Rev. 4 (2017) 011102]. We also report an improved version of this theory that includes a new analytical description of the effect of grain boundary disorder on electron transport. We employ the surface roughness and grain size distribution measured on this Cu film as input data to compute, using our heory, the room temperature resistivity of Cu wires of rectangular cross section, and compare with the resistivity of these wires reported in the literature [M H Van der Veen et al, 2018 IEEE International Interconnect Technology Conference (IITC) (2018)], that are used for designing Integrated Circuits (IC) for the 14 nm, 10 nm, 7 nm, 5 nm, 3 nm and 2 nm nodes, respectively. The quantum theory predicts an increase in resistivity with diminishing wire dimensions that accurately agrees with the room temperature resistivity measured on these Cu wires. The resistivity induced by electron-rough surface scattering accounts for about half of the increase over the bulk observed in the 3 nm and 2 nm tech node; scattering by non-uniform grain boundaries contributes the remaining increase in resistivity—the latter is responsible for the weak Anderson localization. According to the description of electron motion furnished by this improved quantum theory, the break down of Moore’s law with shrinking wire dimensions is to be expected, since it originates from size effects triggered by electron scattering with rough surfaces and scattering by non-equally spaced grain boundaries, which become dominant as the dimensions of the metallic wire shrinks.
The improvement of grain refinement, texture modification and mechanical properties of pure Mg prepared by cyclic expansion extrusion with an asymmetric extrusion cavity
Authors: Shi Yusha , Zheng Jie , Ji Jinsheng , Zhang Heng , Zhang Zhimin , Wang Qiang , Xue Yong
Published: January 2021

In this article, a new type of severe plastic deformation process named cyclic expansion extrusion with an asymmetric extrusion cavity (CEE-AEC), was used to prepare pure magnesium with three passes repetitive deformation at 250 °C. This article mainly studies the microstructure evolution, texture analysis and mechanical properties of pure magnesium. The results display that the grain size is refined, from 74 um to 19 um, which is attributed to continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). With the increasing CEE-AEC passes, the texture is weakened, and the (0001) plane of a large number of grins are inclined from the ED direction. The Schmid factor that activates the basal slip system gradually increases from 0.29 to 0.3 after three passes. After three passes of CEE-AEC, from the tensile tests of the deformed samples at room temperature, it can be seen the samples have excellent comprehensive mechanical properties, the tensile yield strength (TYS) is 54 MPa, ultimate tensile strength (UTS) is 110 MPa, and fracture elongation is 19%.
A New Method for Estimating the Incidence of Infectious Diseases
Authors: McManus Hamish , Callander Denton , Asselin Jason , McMahon James , Hoy Jennifer F , Templeton David J , Fairley Christopher K , Donovan Basil , Pedrana Alisa E , Keen Phillip , Wilson David P , Elliott Julian , Kaldor John , Liaw Siaw-Teng , Petoumenos Kathy , Holt Martin , Hellard Margaret E , Grulich Andrew E , Carr Andrew , Stoove Mark A , Guy Rebecca J
Published: January 2021

Ambitious World Health Organization targets for disease elimination require monitoring of epidemics using routine health data in settings of decreasing and low incidence. We evaluated 2 methods commonly applied to routine testing results to estimate incidence rates that assume a uniform probability of infection between consecutive negative and positive tests based on 1) the midpoint of this interval and 2) a randomly selected point in this interval. We compared these with an approximation of the Poisson binomial distribution, which assigns partial incidence to time periods based on the uniform probability of occurrence in these intervals. We assessed bias, variance, and convergence of estimates using simulations of Weibull-distributed failure times with systematically varied baseline incidence and varying trend. We considered results for quarterly, half-yearly, and yearly incidence estimation frequencies. We applied the methods to assess human immunodeficiency virus (HIV) incidence in HIV-negative patients from the Treatment With Antiretrovirals and Their Impact on Positive and Negative Men (TAIPAN) Study, an Australian study of HIV incidence in men who have sex with men, between 2012 and 2018. The Poisson binomial method had reduced bias and variance at low levels of incidence and for increased estimation frequency, with increased consistency of estimation. Application of methods to real-world assessment of HIV incidence found decreased variance in Poisson binomial model estimates, with observed incidence declining to levels where simulation results had indicated bias in midpoint and random-point methods.
Enhancement of developmentally regulated daidzein secretion from soybean roots in field conditions as compared with hydroponic culture
Authors: Toyofuku Miwako , Okutani Fuki , Nakayasu Masaru , Hamamoto Shoichiro , Takase Hisabumi , Yazaki Kazufumi , Sugiyama Akifumi
Published: January 2021

Analyses of metabolite secretions by field-grown plants remain scarce. We analyzed daidzein secretion by field-grown soybean. Daidzein secretion was higher during early vegetative stages than reproductive stages, a trend that was also seen for hydroponically grown soybean. Daidzein secretion was up to 10 000-fold higher under field conditions than hydroponic conditions, leading to a more accurate simulation of rhizosphere daidzein content.
Network-based methods for gene function prediction
Authors: Chen Qingfeng , Li Yongjie , Tan Kai , Qiao Yvlu , Pan Shirui , Jiang Taijiao , Chen Yi-Ping Phoebe
Published: January 2021

The rapid development of high-throughput technology has generated a large number of biological networks. Network-based methods are able to provide rich information for inferring gene function. This is composed of analyzing the topological characteristics of genes in related networks, integrating biological information, and considering data from different data sources. To promote network biology and related biotechnology research, this article provides a survey for the state of the art of advanced methods of network-based gene function prediction and discusses the potential challenges.
ATSE: a peptide toxicity predictor by exploiting structural and evolutionary information based on graph neural network and attention mechanism
Authors: Wei Lesong , Ye Xiucai , Xue Yuyang , Sakurai Tetsuya , Wei Leyi
Published: January 2021

Motivation: Peptides have recently emerged as promising therapeutic agents against various diseases. For both research and safety regulation purposes, it is of high importance to develop computational methods to accurately predict the potential toxicity of peptides within the vast number of candidate peptides. Results: In this study, we proposed ATSE, a peptide toxicity predictor by exploiting structural and evolutionary information based on graph neural networks and attention mechanism. More specifically, it consists of four modules: (i) a sequence processing module for converting peptide sequences to molecular graphs and evolutionary profiles, (ii) a feature extraction module designed to learn discriminative features from graph structural information and evolutionary information, (iii) an attention module employed to optimize the features and (iv) an output module determining a peptide as toxic or non-toxic, using optimized features from the attention module. Conclusion: Comparative studies demonstrate that the proposed ATSE significantly outperforms all other competing methods. We found that structural information is complementary to the evolutionary information, effectively improving the predictive performance. Importantly, the data-driven features learned by ATSE can be interpreted and visualized, providing additional information for further analysis. Moreover, we present a user-friendly online computational platform that implements the proposed ATSE, which is now available at http://server.malab.cn/ATSE. We expect that it can be a powerful and useful tool for researchers of interest.
PreDTIs: prediction of drug–target interactions based on multiple feature information using gradient boosting framework with data balancing and feature selection techniques
Authors: Mahmud S M Hasan , Chen Wenyu , Liu Yongsheng , Awal Md Abdul , Ahmed Kawsar , Rahman Md Habibur , Moni Mohammad Ali
Published: January 2021

Discovering drug–target (protein) interactions (DTIs) is of great significance for researching and developing novel drugs, having a tremendous advantage to pharmaceutical industries and patients. However, the prediction of DTIs using wet-lab experimental methods is generally expensive and time-consuming. Therefore, different machine learning-based methods have been developed for this purpose, but there are still substantial unknown interactions needed to discover. Furthermore, data imbalance and feature dimensionality problems are a critical challenge in drug-target datasets, which can decrease the classifier performances that have not been significantly addressed yet. This paper proposed a novel drug–target interaction prediction method called PreDTIs. First, the feature vectors of the protein sequence are extracted by the pseudo-position-specific scoring matrix (PsePSSM), dipeptide composition (DC) and pseudo amino acid composition (PseAAC); and the drug is encoded with MACCS substructure fingerings. Besides, we propose a FastUS algorithm to handle the class imbalance problem and also develop a MoIFS algorithm to remove the irrelevant and redundant features for getting the best optimal features. Finally, balanced and optimal features are provided to the LightGBM Classifier to identify DTIs, and the 5-fold CV validation test method was applied to evaluate the prediction ability of the proposed method. Prediction results indicate that the proposed model PreDTIs is significantly superior to other existing methods in predicting DTIs, and our model could be used to discover new drugs for unknown disorders or infections, such as for the coronavirus disease 2019 using existing drugs compounds and severe acute respiratory syndrome coronavirus 2 protein sequences.
Mitochondrial transfer from induced pluripotent stem cells rescues developmental potential of in vitro fertilized embryos from aging females†
Authors: Zhang Chao , Tao Li , Yue Yuan , Ren Likun , Zhang Zhenni , Wang Xiaodong , Tian Jianhui , An Lei
Published: January 2021

Conventional heterologous mitochondrial replacement therapy is clinically complicated by “tri-parental” ethical concerns and limited source of healthy donor oocytes or zygotes. Autologous mitochondrial transfer is a promising alternative in rescuing poor oocyte quality and impaired embryo developmental potential associated with mitochondrial disorders, including aging. However, the efficacy and safety of mitochondrial transfer from somatic cells remains largely controversial, and unsatisfying outcomes may be due to distinct mitochondrial state in somatic cells from that in oocytes. Here, we propose a potential strategy for improving in vitro fertilization (IVF) outcomes of aging female patients via mitochondrial transfer from induced pluripotent stem (iPS) cells. Using naturally aging mice and well-established cell lines as models, we found iPS cells and oocytes share similar mitochondrial morphology and functions, whereas the mitochondrial state in differentiated somatic cells is substantially different. By microinjection of isolated mitochondria into fertilized oocytes following IVF, our results indicate that mitochondrial transfer from iPS, but not MEF cells, can rescue the impaired developmental potential of embryos from aging female mice and obtain an enhanced implantation rate following embryo transfer. The beneficial effect may be explained by the fact that mitochondrial transfer from iPS cells not only compensates for aging-associated loss of mtDNA, but also rescues mitochondrial metabolism of subsequent preimplantation embryos. Using mitochondria from iPS cells as the donor, our study not only proposes a promising strategy for improving IVF outcomes of aging females, but also highlights the importance of synchronous mitochondrial state in supporting embryo developmental potential.
Dynamic erectile responses of a novel penile organ model utilizing TPEM†
Authors: Hashimoto Daiki , Hirashima Tsuyoshi , Yamamura Hisao , Kataoka Tomoya , Fujimoto Kota , Hyuga Taiju , Yoshiki Atsushi , Kimura Kazunori , Kuroki Shunsuke , Tachibana Makoto , Suzuki Kentaro , Yamamoto Nobuhiko , Morioka Shin , Sasaki Takehiko , Yamada Gen
Published: January 2021

Male penis is required to become erect during copulation. In the upper (dorsal) part of penis, the erectile tissue termed corpus cavernosum (CC) plays fundamental roles for erection by regulating the inner blood flow. When blood flows into the CC, the microvascular complex termed sinusoidal space is reported to expand during erection. A novel in vitro explant system to analyze the dynamic erectile responses during contraction/relaxation is established. The current data show regulatory contraction/relaxation processes induced by phenylephrine (PE) and nitric oxide (NO) donor mimicking dynamic erectile responses by in vitro CC explants. Two-photon excitation microscopy (TPEM) observation shows the synchronous movement of sinusoidal space and the entire CC. By taking advantages of the CC explant system, tadalafil (Cialis) was shown to increase sinusoidal relaxation. Histopathological changes have been generally reported associating with erection in several pathological conditions. Various stressed statuses have been suggested to occur in the erectile responses by previous studies. The current CC explant model enables to analyze such conditions through directly manipulating CC in the repeated contraction/relaxation processes. Expression of oxidative stress marker and contraction-related genes, Hypoxia-inducible factor 1-alpha (Hif1a), glutathione peroxidase 1 (Gpx1), Ras homolog family member A (RhoA), and Rho-associated protein kinase (Rock), was significantly increased in such repeated contraction/relaxation. Altogether, it is suggested that the system is valuable for analyzing structural changes and physiological responses to several regulators in the field of penile medicine.
Model Fidelity and Child Well-Being in Family Team Conference: The Interaction Effect of Racial Matching and Child Race
Authors: Kim Jangmin , Choi  Mijin , LaBrenz Catherine A , Harris Marian S , Boyd Reiko , Pierce Barbara J
Published: January 2021

Family Team Conference (FTC) has been suggested as a promising practice model to effectively reduce racial disproportionality and disparities in child welfare. However, previous studies have noted ongoing challenges to promoting cultural responsiveness in FTC. This study analysed caseworkers’ survey data (n = 736) to explore the role of racial matching between caseworkers and children as an effective practice to strengthen the high fidelity of FTC associated with child well-being. The results of the extended regression model indicate that high FTC fidelity was a necessary condition to improve child well-being. However, racial matching was neither a significant factor of child well-being nor a moderator that strengthened the positive association between FTC fidelity and child well-being. Instead, a follow-up analysis showed that caseworkers’ competencies for facilitating FTC were a significant moderator to promote the positive effect of FTC fidelity on the well-being of all children regardless of their race. This paper concludes with research and practice implications to make FTC more culturally responsive to achieve its intended outcomes especially for children of colour.
Participants on Dolutegravir Resuppress Human Immunodeficiency Virus RNA After Virologic Failure: Updated Data from the ADVANCE Trial
Authors: Pepperrell Toby , Venter Willem Daniel Francois , McCann Kaitlyn , Bosch Bronwyn , Tibbatts Melissa , Woods Joanna , Sokhela Simiso , Serenata Celicia , Moorhouse Michelle , Qavi Ambar , Hill Andrew
Published: January 2021

Following evidence of HIV RNA re-suppression on DTG-based regimens, we assess the re-suppressive capacity of ADVANCE participants on TAF/FTC+DTG, TDF/FTC+DTG, and TDF/FTC/EFV. Viraemic participants were able to re-suppress within 3 follow-up visits of protocol-defined virological failure (PDVF) in 77/121 (64%), 85/126 (67%), and 44/138 (32%) cases respectively (DTG regimens vs. TDF/FTC/EFV; P < 0.001).