bluuebunny/crossref_metadata_2025 huggingface dataset:
DStudy on small interference analysis and transmission capacity of UHVAC loop power grid of Shandong–Hebei
Authors: Gao Yu , Xiong Zaibao , Du Shaofei , Geng Xiaohong , Tian Yingtao , Li Yunpeng
Published: February 2021

This paper studies the main operation characteristics, small interference analysis and transmission capacity of UHVAC in Shandong- Hebei loop power grid. It mainly includes the small interference characteristics and section transmission limit analysis of the certain area under the typical mode and maintenance mode, then the operation limit would be defined, so as to provide basic work for the safety and stability calculation of the loop network in the next stage.
Impact on the voltage amplitude on Microquality detection of QCM
Authors: Guo Kai , Jiang Bo , Li Xingeng , Wu Yaping , Tian Shuang , Mi Chunxu , Zong Lijun , Yao Shuo , Zhu Gengzeng , Wang Weina , Zhao Mingzhe
Published: February 2021

The core of environmental pollution detection is quartz crystal microbalance and data acquisition circuit. Under certain conditions, when the quartz crystal vibration surface adsorbs other substances, the natural frequency of quartz crystal vibration changes with the size of adsorption mass, and the frequency is converted into identifiable micro-mass data through the data acquisition circuit. This project USES quartz crystal to detect environmental pollution.
Open Architecture Design of Universal Terminal for Multiple Measurement and Control Scenarios of Distribution Network
Authors: Zhang Ruifeng , Xiao Xiaobing , Tian Hao , Cai Yongxiang , Fu Yu , He Hongliu
Published: February 2021

Introduce the IoT platform technology based on SDN (Software Defined Network), cloud-based, flexible management and configuration of smart terminals, and support access to millions of terminal devices and smart operation and maintenance management. The traditional monitoring system is integrated with the Internet of Things platform, and on the basis of realizing the general SCADA system monitoring function, through the side-cloud collaboration, the lean management of the distribution station area is realized.
Research on countermeasures against slurry foaming and poisoning of desulphurization system in coal-fired power plants
Authors: Song Da , Ma Ying , Xue Fangming , Zhang Yulong
Published: February 2021

With the completion of the ultra-low emission transformation of coal-fired generating units, the boiler flue gas bypass has been completely cancelled. Under extreme operating conditions of the boiler, the flue gas must pass through the desulfurization system. Excessive dust and unburned fuel in the flue gas enter the desulfurization slurry in large quantities, causing slurry bubbles or even overflow, and indirectly leading to a sharp drop in desulfurization efficiency. The emission concentration exceeds the standard. Based on the analysis of previous research results, the reasons for the foaming and overflow of the desulphurization slurry are summarized. Through theoretical analysis of various causes, the countermeasures against foaming and poisoning of desulphurization slurry were proposed and the feasibility of countermeasures was demonstrated through actual cases. It points out the preventive measures for bubble poisoning of limestone-gypsum wet desulfurization slurry, which has important practical guiding significance for the ultra-low SO2 emission of the flue gas of the desulfurization system of coal-fired power plants.
Photovoltaic power generation control strategy
Authors: Yao Zenghui
Published: February 2021

This paper establishes the maximum power tracking technology based on the conductance increment method, establishes the PV model in a synchronous rotating coordinate system, and uses the grid voltage-oriented vector control technology to realize the decoupling of the active and reactive power of the PV. In order to meet the low voltage ride-through requirements put forward by the State Grid Corporation of China, this paper proposes a low voltage ride-through strategy for PV.
Research on Decision Method of Power Grid Project Considering Regulatory Constraints
Authors: Lu Xing
Published: February 2021

A method for selecting power grid investment projects considering the regulatory specifications of transmission and distribution prices is proposed, and the plan is analyzed to provide a better implementation method for power grid planning for power grid companies in market reform.
Modeling and parameter identification of composite power supply for plug-in HEV
Authors: Sun Jingxia
Published: February 2021

By analyzing the characteristics of the components of PHEV composite power supply, the voltage characteristics, temperature characteristics and capacity efficiency of batteries and supercapacitor are clarified. The dynamic voltage characteristics of batteries and supercapacitor are simulated by modeling the composite power supply. Based on the cross current discharge characteristics of lithium-ion batteries and the application conditions of batteries in PHEV, the second-order linear battery model recommended in PNGV is selected in this paper; for supercapacitor, the simplified RC branch model can be used to describe the characteristics, and the experimental data are used to identify the parameters involved in the model, and the accuracy of the model is verified.
New nitriding process of high-alloyed maraging steel for cryogenic operation
Authors: Belashova I S , Bibikov P S , Petrova L G , Sergeeva A S
Published: February 2021

The paper considers the gas nitriding process with cyclic alternation of atmospheres: ammonia and an ammonia mixture with air for strengthening the corrosion-resistant high-alloyed steel 03Cr11Ni10Mo2Ti, designed to operate at cryogenic temperatures. The formation in steel of a nitrided layer of 130—150μm thickness with increased microhardness (more than 12GPa) is shown experimentally. During the final stage in the ammonia and air environment, iron oxides remain in the compound zone, and a sharp drop in hardness is observed at the border of the core. At the completion of the cyclic process with the stage of saturation in ammonia, a nitrides zone is formed based on the γ′-phase, the layer thickness increases (up to 180(…200μm) and the microhardness profile is smoothed, which reduces the risk of embrittlement.
Reduction of mine methane emissions for ensuring sustainable development of geotechnologies in the transition to Industry 3.0
Authors: Dzhioeva A K , Tekhov A V
Published: February 2021

The need to apply innovations in the field of environmental modernization is related to all branches of the domestic industry. Its particular relevance for the enterprises of the mining complex necessitates the neo-industrialization of the integrated development of the subsoil resources. The article defines the conceptual conditions for the development of sustainable geotechnologies. The nonlinear nature of the dynamics of methane release into the methane drainage boreholes has been proved and an explanation of the mechanism for its implementation under the influence of situational geomechanical conditions for developing reserves of high-gas-bearing coal seams has been proposed.
Photo-, cathodic- and electroluminescence-band models in solid (SiC)1-x(AIN)x luminescence centers and SiC/SiC-AIN LEDs
Authors: Dadashev R Kh , Sankin A V , Altukhov V I , Safaraliev G K , Elimkhanov D Z , Antonov V F
Published: February 2021

The paper presents models of bands (levels) in solid (SiC)1-x(AlN)x luminescence centers and n-SiC/p-(SiC)1-x(AlN)x
heterostructures (light-emitting diodes). The diagram of (SiC)1-x(AlN)x
energy gaps shows the positions of luminescence levels, subject to x. A SiC/SiC–AlN series of electroluminescence bands, for the first time, is found to have a continuous relationship between the positions of short-wave and long-wave band maxima in a K-minimum conduction band, respectively, as continuous functions of contact current density.
Designing mining machinery screw modules
Authors: Evstratov V A , Voronova E Yu , Linnik Yu N , Linnik V Yu , Apachanov A S , Grigoryev V I , Suxarnikova V A
Published: February 2021

Screw modules are widely used in technological and transporting machines. Their main disadvantage is low productivity due to the fact that the material moves partly in the direction of the feed and partly rotationally as a result of the torque transmitted by the screw blade to the material. The rotational component of the material movement significantly reduces the performance of the screw. The work considers the possibility of mining machines with screw modules efficiency improving by determining the rational screw shaft configuration, depending on the properties of the feed material and the operating conditions of the module, realized at the designing stage. The aim is achieved by means of a mathematical description of the screw feed process that takes into account processes occurring both on the surfaces of the material contacts with the working bodies of the machine and inside the material mass, including the occurrence of a sliding surface in the material. Furthermore, some part of the material sticks to the screw and moves in concentric circles, with no axial movement in the feed direction, which reduces the performance of the screw. The screw shaft configuration is determined by means of design procedures based on the mathematical description of the screw feeding process, given in the work. The description takes into account the processes occurring in the mass of the feed material. The resulting mathematical model of the screw feeding process allows designing screw shafts with shape identical to the sliding surface in the material, which will increase the performance of the screw module by 20-23%, by reducing the rotational component of the material movement and increasing the translational component in the feed direction.
Automation of individual operations of the transport process to create sufficient conditions for the efficient functioning of digital transport and logistics
Authors: Guseva E A , Konstantinova M V , Olentsevich V A , Konyukhov V Yu , Olentsevich A A
Published: February 2021

The current evolution in information technology will enable the railway industry to bring the concept of a customer-centric marketing approach to life. At present, the main factor for ensuring the competitiveness of the transport company, which emphasizes the position in the transport services market, is to provide a service with a qualitatively new modern level of services, based on the opinion of consumers of these services. The digitalization of railway transport and logistics, the use of modern technical means and programs allows one to improve the efficiency of the transport complex in general and on separate subsystems, as well as to ensure high quality of services. The introduction of an automated procedure for the optimal placement and fastening of the cargo in the production process will allow transport and logistics market operators to predict the occurrence of risk cases at each stage of the transport process. Algorithms for selecting the type of rolling stock to transport the cargo of the relevant category and the typical scheme of placing cargo in it, as well as the method of fixing cargo, have been developed and presented. Since the digitization of supply chains depends more on the type of cargo and the type of rolling stock chosen for transport, the construction of algorithms is based on the example of a flat-base cargo. The development of the automated procedure is based on the construction of a model scheme for placing and fastening a particular type of cargo. The results of using the developed automated procedure make it possible to determine the magnitude of the load shift and tension in the fasteners under the influence of various factors.
Identification of generalized Cobb-Douglass production functions with multiplicative errors in variables
Authors: Sandler I L , Ivanov D V , Lifshits M Yu , Diligenskaya A N
Published: February 2021

The article discusses the identification of a class of generalized Cobb-Douglas production functions with multiplicative errors in all variables. The article proposes a generalization of Cobb-Douglas production functions in the presence of memory for input and output variables. Parametrization of noise in the form of multiplicative noise in all observable variables is proposed. The logarithmic transformation of such production functions leads to the need to solve the problem of estimating the parameters of a linear difference equation in the presence of additive errors in all variables. To identify the parameters of production functions, a modification of the method of total least squares was used. Computational experiments have shown high accuracy of parameter estimation based on the proposed algorithm.
Algorithm for calculating the time of thermal pulse processing of small-sized high-precision parts
Authors: Karlina A I , Ershov V A , Kargapoltsev S K , Gozbenko V E , Karlina Yu I
Published: February 2021

The thermal impulse method of deburring is one of the most promising methods for removing unwanted liquids formed on the surface of small-sized high-precision parts of electronic equipment at the stage of blade machining. The thermal impulse method of deburring and rounding of sharp edges is characterized by constant processing time and quality, subject to the normalized size of liquids. Such qualities can significantly increase the stability of the release of parts in time, and, thanks to this, successfully implement a system of operational scheduling of production. This article describes an algorithm for calculating the time for thermal pulse processing of small-sized parts of coaxial radio components. An example of a basic generalized calculation of the time spent on thermal impulse processing of typical parts using a Pulsar-VKF thermal impulse installation of various configurations is given. Taking into account the peculiarities of thermal pulse processing of parts of coaxial radio components, a method for calculating the batch size and thermal pulse processing time, subject to algorithmization, is developed, conditions and restrictions, input and output information for the algorithm are described. Formulas for calculation are given.
Automation of failure forecasting on the subsystems of the railway transport complex in order to optimize the transportation process as a whole
Authors: Konstantinova M V , Olentsevich A A , Konyukhov V Yu , Guseva E A , Olentsevich V A
Published: February 2021

The existing technology of working with railway rolling stock belonging to various operators should improve the safety of the transportation process. This is one of the priority issues of the operation of the railway transport complex and is aimed at improving the safety of the goods transported, reducing the cost of repairing losses associated with loss or damage to cargo, reducing the non-productive costs of eliminating various types of traffic safety violations. At the same time, the majority of “new” operators providing services do not set out to ensure the safety of the transportation process. The main condition for them is to get the maximum amount of income and profit. These reasons have led to significant changes in the pattern of relations between cargo owners, carrier, rolling stock operator companies and require the speedy automation of most production cycles in order to ensure full control of the situation on the smooth organization of the transportation process. The article assesses the safety of the railway transport complex and constructs a mathematical model of the impact of specific indicators of the violation types on the overall safety level. The described system of mathematical predictive regression-type models can be used in the future to predict the level of security in the selected areas of activity. The factors that have the most significant impact on the safety of technical means by using the developed program complex of failure forecasting have been identified. The proposed program will enable structural managers to make reasoned decisions to improve the safety of the transportation process in both freight and passenger transport.
Combined thermochemical treatment of steel construction parts to increase their corrosion resistance
Authors: Petrova L G , Demin P E , Sergeeva A S
Published: February 2021

Electrochemical corrosion of construction parts made of structural steels appears due to different electrochemical potentials (ECP) of contacting materials. The values of ECP of carbon steels may be more or less compensated by forming of alloyed layers or coatings by methods of thermochemical treatment (TCT). The following combinations of TCT were examined for surface modification of steels: (a) application of zinc coatings by a method of cold zinc-plating with subsequent classical gas nitriding in ammonia; (b) joint diffusion saturation by zinc and nitrogen; (c) joint diffusion saturation with chromium and nickel. Metallographic and microhardness methods were used for the study of modified layers and coatings. Strengthened layers with a thickness up to 140…150 microns were formed in low-carbon steels after nitriding of zinc coatings at 540°C for 24 hours, and after combined TCT with multicomponent saturation by Cr+Ni at 1000°C for 7 hours. Both methods of TCT increase the corrosion resistance of low-carbon steels and low-alloyed steels. Corrosion products examination in 5% NaCl salt fog shows that the dissolution of nitrided Zn coating and formation of corrosion products slow down with the increase of zinc concentration in the coating.
Methodology for the implementation of a technological solution, taking into account the optimization of production business processes based on simulation
Authors: Shanin I I
Published: February 2021

The current production activity of modern commercial organizations is focused on the use of effective technological solutions. The main goal of any commercial organization that carries out production and sales activities is the release of a certain type of industrial product that meets certain consumer and quality characteristics. Any commercial activity is focused on improving the efficiency of technological processes using rational approaches to save production resources to further maximize profits. When building a technological production chain, it is necessary to analyze production business processes, taking into account both the individual needs of consumers in industrial products and taking into account the main goal of a commercial organization, taking into account the introduction of modern technological solutions. The study proposes to introduce an effective technological solution into the production process, based on the results of simulation (for example, furniture production). Therefore, to assess the performance of technological processes and the effectiveness of the use of machinery and equipment, it is necessary to apply an approach to the implementation of an effective technological solution. For this, it becomes necessary to develop an algorithm for the implementation of an effective technological solution, taking into account the optimization of production business processes based on simulation, based on increasing the efficiency of using machines and equipment and reducing downtime in the production process chain.
Method for determining the reduced parameters of the mixer gear drive
Authors: Podgornyj Y I , Skeeba V Y , Martynova T G , Skeeba P Y , Lobanov D V , Martyushev N V
Published: February 2021

The article presents the method of determining the reduced moments of a mixer mechanism with an epicyclic gear and a rocker arm. The method consists of using a mathematical model of the mechanism; determining the change of process load on the device working shaft; determining the dependence of the moments change on inertia forces and their values and reducing them to the main shaft of the device. It also includes determining the dependence of the change in the total moments values on the forces of useful resistance and on the moments of inertia forces and reducing them to the main shaft of the device.
Automated calculation method effect values in load securing elements fixed on a rolling stock
Authors: Vlasova N V , Olentsevich V A , Konyukhov V Yu , Lysenko D A
Published: February 2021

The article presents a method for the automated calculation of the magnitude of the efforts in the means of securing cargo fixed to the rolling stock in accordance with the Technical Conditions for Stowing and Securing Cargo in Wagons and Containers - a regulatory document of JSC Russian Railways (hereinafter referred to as TU). The method provides for all possible factors of the influence of the forces acting on the transported cargo as a result of its movement from the point of loading to the point of unloading, including the necessary technological operations performed along the route, using the example of a cargo with a flat base using the capabilities of the computing environment. The obtained research results are supposed to be used by shippers in the development of the optimal method for placing and securing transported goods on the rolling stock. The automated calculation method will allow obtaining the predicted value of the cargo shift value both along and across the car from the total effect of longitudinal, transverse and vertical forces acting on the cargo along the way. These values make it possible to optimally determine the place of installation of thrust bars on the car floor, depending on the geometric parameters of the transported cargo and the chosen method of fastening it to the rolling stock.
Hydraulic control valve spool restoration by composite galvanic coating
Authors: Yudina E M , Kadyrov M R , Serguntsov A S , Samurganov G E
Published: February 2021

Methods of restoration of hydraulic control valve spools by galvanic coatings are considered. Methods for preparing parts for applying electroplated composite coatings in order to increase the adhesion strength of electrolytic iron to alloy steel are proposed. The optimal modes of electrolysis for obtaining high-quality galvanic coatings are selected, the composition of the electrolyte is substantiated and the optimal content of the dispersed phase in it is selected. The design features of the coating bath for active mixing of the dispersed phase in the electrolyte are substantiated. The parameters of the technological process for spools restoration by applying composite galvanic iron-based coatings are proposed.
On the issue of compensation of spring fittings for parts made by longitudinal stretching
Authors: Mironenko V V , Govorkov A S
Published: February 2021

The paper considers the problem related to the compensation of springing in the fitting of parts produced by longitudinal stretching. The imitating modeling of shaping by longitudinal stretching using elasto-plastic model of material taking into account anisotropy was carried out on the example of one element. The adequacy of modeling was checked according to the following criteria: deformation ratio; thinning; Keller-Godwin’s chart and required shaping force. Conclusions were drawn on the adequacy of modeling. Implicit calculation of springing gradients in an element was carried out and thus the iterative calculation of compensation of springing in the fitting. The negative effect of springing compensation at such scheme of shaping is shown. Change of the springing size in the course of iterative calculation of springing compensation in the fitting is also shown.
Simulation of the method of excitation of pulsations in a moving fluid flow
Authors: Galimullin M L , Khabibullin M Ya , Suleimanov R I
Published: February 2021

The article deals with an important issue of efficiency of using energy supplied into each of the elements of the Venturi-type pipe, i.e. the value of energy efficiency coefficient. The issue coverage requires conducting comparative studies of the specific surface area of bubbles in a gas-liquid system and the mass transfer coefficients in a pipe with a periodically changing cross-section and in a cylindrical pipe with other conditions being equal. The proposed method of excitation of pulsations in a moving fluid flow can be used for the processes of splitting droplets and bubbles in a continuous liquid phase, since this creates favorable conditions - significant amplitudes of pressure, speed and acceleration at a frequency of about dozens of Hertz.
Modelling viscous fluid filtration to select optimal bottom-hole filter designs
Authors: Soloviev N N , Khabibullin M Ya
Published: February 2021

Determining the resistance value of filters with a filtering surface of mesh and block type is difficult mathematically. This is because many parameters affecting the shell filtration capacity. As for the mesh filters, depending on the type of weaving, the different thickness of weft and warp, the different size in the horizontal and vertical planes, the frame structure which is integral with the mesh have critical influence. As for block constructions, it is the size and uniformity of the composition of the particles, the thickness of the filter shell, the geometry of the filtration channels and other features that play the role. It is, therefore, more convenient for such filters to assess their permeability. The most promising filters are the frames with horizontal slots which have considerably less resistance and interference of the holes. In addition, the features of the frame-rod filter device make it easy to realize a greater inlet area than in other designs, with the same minimum size of the slots. Recommendations for choosing the inlet areas and the size of the filter slots should consider factors related to well production rate, the formation fluid viscosity, particle size distribution of the formations, granulometric composition of the formation, consolidation factor of the bottom-hole zone, clodding and bridging of the deposits.
Enhancement of efficiency of the hydraulic distributor of the hydraulic drive of the bottom-hole pump
Authors: Suleimanov R I , Khabibullin M Ya
Published: February 2021

The article deals with the hydraulic drive of the bottom-hole pump and analyzes the hydraulic drive operation. The authors outline peculiar failures of the hydraulic distributor of oil system control and suggest a technical solution for efficient operation of a hydraulic distributor designed to redirect the flow of liquids circulating in the hydraulic drive of the bottom-hole pump. The solution allows increasing the inter-repair period and reducing the energy consumption of the hydraulic drive.
Selection and justification of efficiency parameters of a noise-resistant downhole telemetry system
Authors: Tyncherov K T , Mukhametshin V Sh , Rakhimov N
Published: February 2021

The article examines the issue of selecting and justifying efficiency parameters of a noise-resistant downhole telemetry system that measures and transmits borehole information to the surface via an electromagnetic communication channel. The work is devoted to the continuation of research on the synthesis of systems capable of transmitting messages from oil wells equipped with sucker rod pumps from a depth of up to two thousand meters. To ensure noise immunity, coding is proposed in the residual class system with the possibility of error correction in the neural network basis.
Geological and technological justification of the bottom-hole zone treatment of wells and formations of the Langepas group of fields
Authors: Yaskin S A , Mukhametshin V V , Kuleshova L S
Published: February 2021

Based on the geological and routine analysis are represented the effective application areas of methods of simulating production and enhanced oil recovery of fields developed by the TPP “Langepasneftegaz”. Based on laboratory experiments, the composition of composite systems of recovery methods on productive formations has been established. The technologies adaptation of the bottom-hole zone treatment of wells and formations of the Langepas group of fields was carried out.
The controlled SWAP test for determining quantum entanglement
Authors: Foulds Steph , Kendon Viv , Spiller Tim
Published: February 2021

Quantum entanglement is essential to the development of quantum computation, communications, and technology. The controlled SWAP test, widely used for state comparison, can be adapted to an efficient and useful test for entanglement of a pure state. Here we show that the test can evidence the presence of entanglement (and further, genuine n-qubit entanglement), can distinguish entanglement classes, and that the concurrence of a two-qubit state is related to the test’s output probabilities. We also propose a multipartite measure of entanglement that acts similarly for n-qubit states. The average number of copies of the test state required to detect entanglement decreases for larger systems, to four on average for many (n ≳ 8) qubits for maximally entangled states. For non-maximally entangled states, the number of copies required to detect entanglement increases with decreasing entanglement. Furthermore, the results are robust to second order when typical small errors are introduced to the state under investigation.
Investigating the effects of B-site Cr doping on the structural, magnetic and magnetocaloric properties of La1.4Ca1.6Mn2−

x
Cr
x
O7 (0 ⩽ x ⩽ 0.4) bilayer manganites
Authors: Kumar Akshay , Kumari Kavita , Koo Bon Heun
Published: February 2021

In this work, we describe the preparation of a series of Cr-substituted La1.4Ca1.6Mn2−x
Cr
x
O7 (x = 0.0, 0.1, 0.2, 0.3, 0.4) double-layer perovskite compounds using a solid-state reaction method. The XRD patterns of all the samples are characterized by a tetragonal structure with a bilayer Ruddlesden–Popper phase. Scanning electron microscope micrographs of the doped samples display ambiguous granular variation and distribution, thereby establishing that the Cr content adversely influences the diffusion kinetics during the sintering process. Combined field-cooled moment vs temperature (M–T) and isothermal magnetization measurements establish the presence of a ferromagnetic to paramagnetic transition in all samples. Furthermore, the second-order nature of the transition is identified using the Arrott plots for these compounds. The maximum values of the change in isothermal entropy are found to be 2.98 J kgK−1, 2.39 J kgK−1, 1.48 J kgK−1, 1.29 J kgK−1, and 1.13 J kgK−1 for samples with x = 0.0, 0.1, 0.2, 0.3, and 0.4, respectively, when exposed to a field of 2.5 T. The entropy curves of the pristine sample are bounded within a narrow range of temperatures while the isothermal entropy curves are broadly expanded over a range of temperatures upon Cr-doping. The broad entropy profiles of the Cr-doped compounds versus temperature suggest a relatively high magnetocaloric potential, compared to the parent compound.
Facelift Part II: Surgical Techniques and Complications
Authors: Hashem Ahmed M , Couto Rafael A , Surek Chris , Swanson Marco , Zins James E
Published: February 2021

Although previous publications have reviewed face and necklift anatomy and technique from different perspectives, seldom were the most relevant anatomical details and widely practiced techniques comprehensively summarized in a single work. As a result, the beginner is left with a plethora of varied publications that require sorting, rearrangement, and critical reading. A recent survey of US plastic surgery residents and program directors disclosed less facility with facelift surgery compared with aesthetic surgery of the breast and trunk. To this end, 4 of the widely practiced facelift techniques (ie, minimal access cranial suspension-lift, lateral-SMASectomy, extended-SMAS, and composite rhytidectomy) are described in an easy review format. The highlights of each are formatted followed by a summary of complications. Finally, the merits and limitations of these individual techniques are thoroughly compared and discussed.

Level of Evidence: 4
Anthropogenic noise alters parental behavior and nestling developmental patterns, but not fledging condition
Authors: Pandit Meelyn Mayank , Eapen James , Pineda-Sabillon Gabriela , Caulfield Margaret E , Moreno Alexander , Wilhelm Jay , Ruyle Jessica E , Bridge Eli S , Proppe Darren S
Published: February 2021

Anthropogenic noise is a ubiquitous feature of the American landscape, and is a known stressor for many bird species, leading to negative effects in behavior, physiology, reproduction, and ultimately fitness. While a number of studies have examined how anthropogenic noise affects avian fitness, there are few that simultaneously examine how anthropogenic noise impacts the relationship between parental care behavior and nestling fitness. We conducted Brownian noise playbacks for 6 h a day during the nesting cycle on Eastern Bluebird (Sialia sialis) nest boxes to investigate if experimentally elevated noise affected parental care behavior, nestling body conditions, and nestling stress indices. We documented nest attendance by adult females using radio frequency identification (RFID), and we assessed nestling stress by measuring baseline corticosterone levels and telomere lengths. Based on the RFID data collected during individual brood cycles, adult bluebirds exposed to noise had significantly higher feeding rates earlier in the brood cycle than adults in the control group, but reduced feeding rates later in the cycle. Nestlings exposed to noise had higher body conditions than the control nestlings at 11 days of age, but conditions equalized between treatments by day 14. We found no differences in nestling baseline corticosterone levels or nestling telomere lengths between the two treatment groups. Our results revealed that noise altered adult behavior, which corresponded with altered nestling body condition. However, the absence of indicators of longer-term effects of noise on offspring suggests adult behavior may have been a short-term response.
Deep-ABPpred: identifying antibacterial peptides in protein sequences using bidirectional LSTM with word2vec
Authors: Sharma Ritesh , Shrivastava Sameer , Kumar Singh Sanjay , Kumar Abhinav , Saxena Sonal , Kumar Singh Raj
Published: February 2021

The overuse of antibiotics has led to emergence of antimicrobial resistance, and as a result, antibacterial peptides (ABPs) are receiving significant attention as an alternative. Identification of effective ABPs in lab from natural sources is a cost-intensive and time-consuming process. Therefore, there is a need for the development of in silico models, which can identify novel ABPs in protein sequences for chemical synthesis and testing. In this study, we propose a deep learning classifier named Deep-ABPpred that can identify ABPs in protein sequences. We developed Deep-ABPpred using bidirectional long short-term memory algorithm with amino acid level features from word2vec. The results show that Deep-ABPpred outperforms other state-of-the-art ABP classifiers on both test and independent datasets. Our proposed model achieved the precision of approximately 97 and 94% on test dataset and independent dataset, respectively. The high precision suggests applicability of Deep-ABPpred in proposing novel ABPs for synthesis and experimentation. By utilizing Deep-ABPpred, we identified ABPs in the tail protein sequences of Streptococcus bacteriophages, chemically synthesized identified peptides in lab and tested their activity in vitro. These ABPs showed potent antibacterial activity against selected Gram-positive and Gram-negative bacteria, which confirms the capability of Deep-ABPpred in identifying novel ABPs in protein sequences. Based on the proposed approach, an online prediction server is also developed, which is freely accessible at https://abppred.anvil.app/. This web server takes the protein sequence as input and provides ABPs with high probability (>0.95) as output.
Places that matter: Australia’s crisis intervention framework and voter response
Authors: Weller Sally
Published: February 2021

This article contributes to understandings of geographies of discontent by focusing on the way that political frameworks condition the demand for fringe or protest voting. It discusses how Australia’s federal political framework, preferential voting system and timely crisis intervention policies combine to reduce the demand for fringe voting. The local effects of this system are illustrated via an examination of voting patterns in two disadvantaged and deindustrialising locations in the State of Victoria. The conclusion suggests that European jurisdictions have much to learn from the Australian example.
Elevated septal wall stress - a driver of left ventricular dysfunction in left bundle branch block?
Authors: Sletten OJ , Aalen JM , Remme EW , Izci H , Duchenne J , Larsen CK , Hopp E , Galli E , Sirnes PA , Kongsgard E , Donal E , Voigt JU , Smiseth OA , Skulstad H
Published: February 2021

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): The Norwegian Health Association

Background

Septal dysfunction is a main feature of left bundle branch block (LBBB), and increasing wall stress is a proposed mechanism of heart failure development in LBBB patients. To try to reveal the pathophysiologic pathway from dyssynchrony to heart failure, we investigated the relationship between septal and left ventricular (LV) lateral wall stress in patients with LBBB.

Hypothesis

Increased septal wall stress causes septal dysfunction in LBBB.

Methods

We included 24 LBBB-patients (65 ± 11 years, 11 males) with LV ejection fraction (EF) ranging from 18 to 67%, and 8 healthy controls (58 ± 10 years, 4 males). Wall stress was calculated at peak LV pressure (LVP) according to the law of La Place ([LVP x radius]/[wall thickness]). Wall thickness was measured using M-mode, and regional curvature was measured in mid-ventricular shortaxis from 2D echocardiographic images. We used a previously validated non-invasive method to estimate LVP from brachial blood pressure and adjusted for valvular events. Myocardial scar was ruled out by late gadolinium enhancement cardiac magnetic resonance imaging.

Results

Wall stress was significantly higher in septum than LV lateral wall at peak LVP (48 ± 12 vs 37 ± 11 kPa, p < 0.01) in LBBB patients, while no difference was seen in the controls (Figure A). In patients, septal wall thickening showed a strong correlation with LVEF (r = 0.77, p < 0.01) (Figure B). Similar correlation was not significant for the LV lateral wall (r = 0.13, NS). Attenuation of septal wall thickening in LBBB-patients correlated well with increasing septal wall stress (r=-0.60, p < 0.01). Wall thickening and stress did not correlate in the LV lateral wall (r=-0.14, NS).

Conclusion

Increased septal wall stress is associated with reduced systolic thickening in patients with LBBB. Septal wall thickening, in contrast to LV lateral wall thickening, was correlated to global LV function. These findings suggest that septal remodeling which could have normalized septal wall stress, was not achieved and heart failure may develop.

Abstract Figure.
Diastolic dyssynchrony in patients with LV only fusion pacing CRT without RV lead
Authors: Gurgu A , Petrescu L , Vacarescu C , Luca CT , Mornos C , Crisan S , Lazar MA , Cozma D
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Background

CRT improves both systolic and diastolic function, thus increasing cardiac output. However, less data is available concerning diastolic dyssynchrony and fusion pacing CRT. The aim of our study was to assess the outcome of LV diastolic asynchrony in a population of fusion pacing CRT without right ventricular (RV)  lead.

Methods

Prospective data were collected from a cohort of patients (pts) with right atrium/left ventricle leads (RA/LV CRT). Baseline and every 6 months follow-up included standard ETT and classical dyssynchrony parameter measurements. Diastolic dyssynchrony was done by offline speckle-tracking derived TDI timing assesment of the simultaneity of E" and A"  basal septal and lateral wall 4 chamber view. New parameters were introduced: E" and respectively A" time (E"T / A"T) as the time difference between E" (respectively A" ) peaks septal and lateral wall. Exercise tests, drugs optimization and device individual programmimg were systematically performed in order to maintain constant fusion and improve CRT response. Patients were divided in three groups: super-responders (SR), responders (R) and non responders (NR).

Results

Sixty-two pts (35 male) aged 62 ± 11 y.o. with idiopathic DCM implanted with a RA/LV CRT were analyzed: 34%SR / 61%R / 5%NR. Baseline initial characteristics: QRS 164 ± 18 ms; EF 27 ± 5.2; 29% had type III diastolic dysfunction (DD), 63% type II DD, 8% type I DD. Average follow-up was 45 ± 19 months; mean LVEF at the last follow-up was 37 ± 7.9%. The E"T decreased from 90 ± 20 ms to 25 ± 10 ms in SR with significant LV reverse remodelling (LV end-diastolic volume 193.7 ± 81 vs 243.2 ± 82 ml at baseline, p < 0.0028) and lower LV filling pressures (E/E" 13.2 ± 4.6 vs 11.4 ± 4.5, p =0.0295). DD profile improved in 65% of R with a reduction in E/A ratio (1.46 ± 5.3 vs. 0.82 ± 3.9 at baseline, p= 0.4453). Non-sudden cardiac death occurred in 3 NR pts (2%) with type III DD, severe LA volume and larger E" T /A"T (E"T> 85 msec A"T > 30 msec).  Significant cut off value calculated by ROC curve for LV diastolic dyssynchrony is E"T > 80 ms and A"T of > 25 msec.

Conclusions

Fusion pacing CRT without RV lead showed a positive outcome; improving LV diastolic dyssynchrony in responders and super-responders patients is obvious. Larger randomized studies are needed to define the role of diastolic asynchronism as a predictor of favorable response in fusion pacing.

Abstract Figure. Typical TDI patterns in LV fusion pacing
Importance of systematic right ventricular assessment in cardiac resynchronization therapy candidates: a machine-learning approach
Authors: Galli E , Le Rolle V , Smiseth OA , Duchenne J , Aalen JM , Larsen CK , Sade E , Hubert A , Anilkumar S , Penicka M , Linde C , Leclercq C , Hernandez A , Voigt J-U , Donal E
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Background

Despite having all a systolic heart failure and broad QRS, patients proposed for cardiac resynchronization therapy (CRT) are highly heterogeneous and it remains extremely complicated to predict the impact of the device on left ventricular (LV) function and outcomes.

Objectives

We sought to evaluate the relative impact of clinical, electrocardiographic, and echocardiographic data on the left ventricular (LV) remodeling and prognosis of CRT-candidates by the application of machine learning (ML) approaches.

Methods

193 patients with systolic heart failure undergoing CRT according to current recommendations were prospectively included in this multicentre study. We used a combination of the Boruta algorithm and random forest methods to identify features predicting both CRT volumetric response and prognosis (Figure 1). The model performance was tested by the area under the receiver operating curve (AUC). We also applied the K-medoid method to identify clusters of phenotypically-similar patients.

Results

From 28 clinical, electrocardiographic, and echocardiographic-derived variables, 16 features were predictive of CRT-response; 11 features were predictive of prognosis.

Among the predictors of CRT-response, 7 variables (44%) pertained to right ventricular (RV) size or function. Tricuspid annular plane systolic excursion was the main feature associated with prognosis. The selected features were associated with a very good prediction of both CRT response (AUC 0.81, 95% CI: 0.74-0.87) and outcomes (AUC 0.84, 95% CI: 0.75-0.93) (Figure 1, Supervised Machine Learning Panel). An unsupervised ML approach allowed the identifications of two phenogroups of patients who differed significantly in clinical and parameters, biventricular size and RV function. The two phenogroups had significant different prognosis (HR 4.70, 95% CI: 2.1-10.0, p < 0.0001; log –rank p < 0.0001; Figure 1, Unsupervised Machine Learning Panel).

Conclusions

Machine learning can reliably identify clinical and echocardiographic features associated with CRT-response and prognosis. The evaluation of both RV-size and function parameters has pivotal importance for the risk stratification of CRT-candidates and should be systematically assessed in patients undergoing CRT.

Abstract Figure 1
Left ventricular remodelling patterns after MitraClip implantation: Do ischemic patients have the same benefit?
Authors: Viegas J , Reis JF , Branco LM , Galrinho A , Fiarresga A , Ramos R , Cacela D , Fernandes F , Celas M , Ferreira RC
Published: February 2021

Funding Acknowledgements

Type of funding sources: None.

Introduction

 Percutaneous mitral valve repair has shown to prevent and even reverse adverse LV remodelling in most patients with moderate to severe mitral regurgitation (MR). This effect is, however, highly variable and may differ according to the MR etiology.

Objectives

 The aim of the present study is to evaluate cardiac remodelling patterns and clinical outcomes after MitraClip implantation (MI) in ischemic and non-ischemic patients (P).

Methods

 A standardized registry was prospectively performed between 2013 and 2019 for all P who underwent MitraClip insertion in a single terciary care centre. Transthoracic echocardiographic information was assessed at baseline and 1, 6, 12 and 18 months after MI. Student’s t-test was used to assess the procedure’s effect on several variables. Clinical outcomes were compared with the use of Fisher’s exact test or the chi-square test, as appropriate.

Results

 46 P, 61% male, mean age 65 ± 14 years. 39% had ischemic MR. Dyslipidemia was more frequent in ischemic P (52% versus 93%, p= 0.002) as well as history of smoking (32% versus 67%, p= 0.022). Atrial fibrillation was significantly associated with non-ischemic etiology (75% versus 44%, p= 0.036). MI success rate was 87% (proper placement and reduction in MR to grade 2 or less), with an average of 1.5 clips. Considering the 37 P that completed 18 months of follow-up (FU), the echocardiographic parameters at baseline were: left ventricular ejection fraction (LVEF) 36 ± 12%, LV end-diastolic dimeter (LVEDD) 68.2 ± 10.2mm, LV end-systolic diameter (LVESD) 52.2 ± 13.5mm and left atrial diameter (LAD) 53.1 ± 6.7mm; there were no significant differences between groups. After MI, a compelling difference in LVEDD was noticeable early in the first month, with significant lower dimensions in non-ischemic P (66.6 ± 11.4 versus 72.8 ± 5.4, p= 0.039). Sustained differences in LVEDD were consistent at 6, 12 and 18 months (62.4 ± 12.3 versus 73.5 ± 7.4, p= 0.025). There was also a reduction in LVESD that became apparent in the sixth month (45.5 ± 15.1 versus 55.3 ± 9.8mm, p= 0.047) and that was sustained after 18 months from MI (45.4 ± 11.7 versus 58.3± 8.9, p= 0.012). No significant differences in LVEF or LAD were noticed over time. Regarding clinical outcomes at 18 months, overall mortality (M) was 24% (9P) and 51% (19P) died or were hospitalized due to heart failure (MH).  No difference was found between groups: M (p= 0.119), MH (p= 0.091).

Conclusion

 This study reports better LV reshape effects after MI in P with non-ischemic etiology, with sustained improvement over time. However, no differences regarding mortality or hospitalization due to HF were apparent at the 18-month FU. Larger long-term studies are required to evaluate these results.

Abstract Figure. LV remodelling pattern