bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of passive protection devices for a power head of a high-speed multiple unit train at its collisions
Authors: Sobolevska M , Horobets D , Syrota S
Published: December 2020

Ukrainian passenger multiple-unit train upgrading supposes on creation of new power heads with passive safety systems (PSS) to save passengers lives, to reduce rolling stock damage and to minimize consequences at collisions. The purpose of this research is to develop energy absorption devices (EADs) for power head PSS according to DSTU EN 15227. EAD 1, EAD 2, EAD 3 designs have been developed with using successful experience of EP20 locomotive EADs creation and EAD prototype crash test results. EAD 1 design includes two elements which are located sequentially. Element 1 is a box with a single-layer package of hexagonal honeycombs inside. Element 2 is a truncated pyramid of honeycombs with triangular cells. EAD 2 design has three steps in element 2 form. EAD 3 design has been developed on the basis of element 1. It has been recommended to install two EAD 1 in a power head frontal part at the coupling level, two EAD 2 in power head window-sill part and two EAD 3 in the inter-car connection at the coupling level. Finite element simulation of EAD plastic deformation at an impact has been carried out for determination of design parameters.
Choosing of Asynchronous Motor Protection Equipment in Production Environment
Authors: Kuznetsov V V , Tryputen M M , Kuznetsov V G , Tryputen M , Kuznetsova A , Kuznetsova Y
Published: December 2020

The current article is devoted to the topic problem of decision making concerning the choice of the protective means for asynchronous motors operated within industrial shop electric circuits under challenging conditions of improper electric supply. In this paper we show how energy economizing model for the asynchronous motor can be presented in the form of predicate disjunction and be applied with the pattern recognition algorithm for making solutions. The major advantage of a new model is its open character and the possibility of knowledge accumulation with respect to electromechanical equipment. We submit the information on the software and hardware complex applied for the research on the characteristics of the circuit voltage and the asynchronous motors in the real time mode directly within the enterprise industrial shop. The publication also reports on the searching for the best protective solution for asynchronous motors. This work is based on the known recognition algorithm of statistical optimization for non-linear objects given as the aggregates of predicates. The algorithm fruitfully applies the local selection principle. The approach proposed in this publication has been approbated at the protective means selection procedure for the asynchronous motor of 7.5 kW capacity, which performance is 80% of the working cycle under conditions of improper electric energy supply in the experimental shop of Ukrspetsservis.
Formulation of the mathematical model for the planning system in the carriage of dangerous goods by rail
Authors: Bibik S , Strelko O , Nesterenko H , Muzykin M , Kuzmenko A
Published: December 2020

The paper aims to the topical issue of improving the system in the planning of carriage of dangerous goods by rail subject to ensuring a high level of safety of the transport process and minimal costs for its implementation. Formalization of this process leads to the formation of an optimization task of the two-stage mathematical model. To implement the first stage, a mathematical model in searching the best route based on risk minimization is developed. In order to exclude the unacceptably complex and expensive options for the carriage of dangerous goods from the many possible routes, the authors abided by the condition not to exceed the critical operating costs. The second stage in the process of planning routes for dangerous goods takes into account the hazard identification study in the technological process of car movement with dangerous goods. Considering that the probability of a potential traffic accident is a complex random variable, which is due to a set of elementary previously unknown events, its estimation was made on the basis of the Bayesian approach. Based on the simulation results, the following reliability values are determined at which a transport accident should not emerge.
Coefficient of stability against lift by longitudinal forces of freight cars in trains
Authors: Shvets A O , Shatunov O V , Dovhaniuk S S , Muradian L A , Pularyia A L , Kalashnik V V
Published: December 2020

The paper is devoted to a theoretical study of the car movement stability when exposed to longitudinal forces of a quasistatic nature. The authors obtained the expressions for calculating the resistance coefficient of the car lift by the longitudinal compressive force acting on the car as part of a freight train. The influence of some factor’s combination on the longitudinal forces, at which the car movement stability is still maintained, was analyzed using the analytical dependencies to assess the longitudinal loading of cars in trains. The study was carried out by analytical method for assessing the freight car stability when moving at different speeds along curved track sections. The calculations were made in a curve of small radius taking into account the inertia forces from the unbalanced acceleration. In a theoretical study, the influence of quasistatic longitudinal compressive forces depending on changes in speed and force value, as well as the influence of friction in the wheel flange and rail contact and the eccentricity of fastening the automatic coupler shank on the stability were considered. When applying the results obtained, the stability of freight rolling stock can be increased, which in turn will remove some existing restrictions on the permissible speeds and increase the technical speed of train movement. Using the described methodology for determining the lift resistance coefficient will make it possible to justify the cause of derailment, as well as to develop and put into practice technical measures to prevent the lift of carriages, thrusts and shears of the track.
Study of strength characteristics of the long wheelbase flat cars
Authors: Fedosov-Nikonov D V , Sulym A O , Ilchyshyn V V , Safronov O M , Kelrikh M B
Published: December 2020

Transportation of goods in large containers with loading length of 80 feet is one of the promising directions of railway transport development. However, despite considerable experience in construction of long-wheelbase flat cars, occasionally problems with the strength of load-bearing elements arise at the calculation, design and manufacture of such products. The article presents the technical characteristics of a long wheelbase flat car, as well as the results of experimental studies of fatigue tests of its load-bearing elements. The optimization of the design of the long wheelbase flat car was achieved both by increasing the sizes and shapes, and by using materials of increased strength. An analysis of the study’s results of an improved design showed the compliance of the values of the safety factor of fatigue strength and the service life of the flat car with regulatory and technical documentation. The conducted studies allow us to make recommendations regarding the design, rebuilding and testing of long wheelbase flat cars. The primary results of fatigue tests of the main load-bearing structural elements within the scope of experimental studies turned out to be mostly below acceptable values. This article contains facts confirming it. The results of experimental studies to determine the fatigue strength proved that the design elements require improvement and strengthening.
Improvement of diesel injector nozzle test techniques
Authors: Aulin D , Klymenko O , Falendysh A , Kletska O , Dizo J
Published: December 2020

Due to changes in the characteristics of the fuel equipment during operation, a considerable part of the life cycle of locomotive engines operate under increased fuel consumption, and thermal voltage, which often causes degraded environmental performance and reduced engine capacity and, as a result, low efficiency of the locomotive. A reserve for improving the performance of the diesel plant and the diesel locomotive in general is the implementation of measures to prevent changes in the characteristics of the fuel system, for example, the development of clean-in-place technique of fuel systems from carbon deposits. In order to determine the effectiveness of such measures, it is necessary to apply new quality control methods of fuel atomization. The article offers a more informative method for evaluating the quality of fuel atomization, which can be used in locomotive depots during research and development work. The method consists of microphotography of the drops of sprayed fuel followed by microscopic analysis and processing of the results using special software. It is proposed to process the results of injectors testing using a statistical method, taking into account the parameters according to the Rosin-Rammler dependence for the relative total curve. As a result of the work, it became possible to develop requirements and implement technical improvements to the test stands for fuel equipment of diesel locomotives.
Analysis of physical and chemical transformations during thermal spraying of coatings based on carbides of tungsten and chromium
Authors: Kharlamov Yu O , Sokolov V I , Krol O S , Romanchenko O V
Published: December 2020

The formation of structure and properties of thermal coatings is largely determined by the transformation intensity of sprayed materials at all stages of obtaining of coating. It is shown that during D – gun spraying, in order to ensure optimal conditions for leading transformations and phenomena that have a decisive influence on structure and properties of sprayed coatings, composition of combustible mixture, geometry and dimensions of barrel, conditions for introducing powder into the barrel and a unit dose of powder, spraying distance, timing of spraying cycle and other technological methods can be used. The possibility of transformation in powders of tungsten carbide and chromium under different methods of thermal spraying is analyzed and the structure and properties of coatings are obtained. The influence of the conditions of D – gun spraying on spraying distances, gas flow rates, type of powder, etc.; phase composition and properties of coatings is studied. The basic physicochemical transformations that accompany D – gun spraying of coatings of alloy WC – C, such as oxidation and reduction of tungsten carbide in high – temperature oxygen – containing media, interaction of composite coating components are considered problems of modelling of bonding of particles with a part surface during thermal spraying of coatings are considered.
Technology of soil compaction of the base of the track with vibrating static machines of blocking action
Authors: Hlavatskyi K , Cherkudinov V , Posmitiukha O
Published: December 2020

The directions of combination of working bodies in the existing soil compactors and machines of the new generation and the technologies of their application for productive and effective soil compaction of the lower track structure, soil structures of roads and other construction objects are given. The basis of the research is the principle of accelerated soil compaction due to the creation on the surface of the contact with the working bodies of the sealing machines pressure, which exceeds the limit of plasticity of the soil and at the same time limiting the slipping of the sides from under the working sealing surface. It is proposed that the working sealing surface modular type that can change its profile depending on the technological requirements. Further research is aimed at creating the required profile of the working body based on the desired compaction core and the structural formula of the working body of the soil compactor. In this case, replacing the elements in the working bodies with the corresponding mathematical models, we obtain a common mathematical model of the working body of the soil compactor, as well as the profile of its working body, based on the specified energy consumption and technological requirements.
Higher efficiency of control over functional status of locomotive crew members
Authors: Brusentsov V , Puzyr V , Vorozhbiian M , Ivashchenko M , Datsun Yu
Published: December 2020

The objective of the study is research into psycho-physiological methods of control over the functional status of a person for higher efficiency of a pre-trip control of locomotive crew members. It is related to the fact that today’s medical methods do not reveal some states which decrease a functional reliability level, particularly, a fatigue level and borderline states. The authors selected parameters which, according to the functional system theory, give information on conditions of two regulation levels in the human body, physiological and higher nervous activity, and correspond to the formulated requirements in terms of the procedure. The study experimentally proved the informative value of 27 psycho-physiological parameters for estimation of exhaustion and borderline states. For a state of exhaustion the hemodynamic parameters, including those of arrhythmia, both sinus and slow waves, were of the most informative value. The study revealed the parameter of arterial pressure pulse, the value of which in the post-trip group decreased by 25%. While identifying existence of borderline states by sinus arrhythmia parameters, it turned out that much more people with borderline states were in the exhaustion zone, rather than in the control group (42% and 16% respectively).
Design, fabrication and analysis of compaction die for powder processing
Authors: Sharma Avadesh K , Singh Rajeev , Tiwari Arun K , Sharma Ajay K
Published: December 2020

A compaction die has an essential role in the powder metallurgy process due to the controlling and ease of processing. The shape and properties of die can significantly affect the features of the final part as the several steps and assessments are involved before design and fabrication of compaction die. This work is an effort to design and manufacture a compaction die that can successfully use for uni-axial compaction of NiTi powder. The design and development of die includes design consideration, 2D drawing, 3D model and processes involved in the fabrication of die. The die design was analyzed by ANSYS 19.1 software in a simulated environment, and the fabricated die was tested experimentally by preparing the composite sample successfully at 1000MPa compaction pressure using universal testing machine. Further, the compaction behaviour, density, compressive strength and hardness of developed NiTi composite have also evaluated.
Heuristics based hybrid approach of flow shop scheduling problem
Authors: Lokesh K , Jayaprakash J , Alene Tibebu
Published: December 2020

In recent day’s furniture fabrication industries are one of the upcoming segments in developing countries. In the fast-developing economy and populations are substantial interest in house hold furniture and wooden games things. Almost around more than 100 medium and large furniture businesses are running in every district capital. Presently they are confronting additionally testing undertakings in adjusting of cycle arranging and assembling products based on customer requirements. In this paper, we have taken scheduling issues related with these enterprises. In the case company contain a set of tasks to be carried out and optimize make span with a set of machines available to perform those jobs. So as to lead important information writing study on past investigations, we proposed heuristics-based hybrid approach of flow shop scheduling problems to assess the make span. At last, we verify the outcomes of the hybrid approach with LEKIN programming.
Novel approach to enhance network security using key performance indicator in business analytics
Authors: Saranya M. , Anithaashri T. P.
Published: December 2020

In Recent days, the challenges in Business applications are more in analyzing the complexities of day to day activities. Key execution pointer (KPIs) are business estimations used by corporate bosses and various directors to follow and examine factors thought about noteworthy to the achievement of a Business. Reasonable KPIs base on the business cycles and limits that senior organization sees as commonly huge for assessing progress toward meeting imperative destinations and execution targets. KPIs differ from relationship to affiliation subject to business needs. One of the key display pointers for an open association will likely be its stock expense, while a KPI for a covertly held startup may be the amount of new customers incorporated each quarter. Surely, even direct adversaries in an industry are likely going to screen different plans of KPIs specially designed to their individual business procedures and the leader’s strategies for thinking.
The influence of thermodynamical characteristics of high speed steels on temperature and forces values when turning construction steel
Authors: Beskopylny A N , Fominov E V , Shuchev C G , Egorov M S
Published: December 2020

The article is devoted to the critical problem of studying the dependencies of temperature and cutting forces on the entropy of tool materials (high-speed steels - HSS). The high wear resistance of the cutting tool is closely related to the entropy of tool materials. However, the relationship of entropy as structural sensitive characteristic with temperature and forces during machining processes is poorly investigated. The experimental studies were carried out on the engine lathe with an infinitely variable regulation of spindle rotation frequencies, equipped with a measuring complex, allowing cutting forces and temperature recording at different cutting speeds. It has been established experimentally that at all cutting speeds in the studied range the smallest values of cutting forces and contact temperatures were characteristic for cutting tools made of HSS with high levels of thermal entropy. Thus, the thermal entropy of HSS can be used to the preliminary assessment of relative values of cutting forces and temperatures during the processing of steels which characteristics are strongly connected with wear rates and reliability of cutting tools.
Determination influence of graphite grade on tribological properties of friction material based on tin bronze when using “A” and ATF-III grade oils
Authors: Biryukov V P , Ilyushchenko A F , Leshok A V , Rogovoy A N
Published: December 2020

The paper presents the results of metallographic and tribological studies of tin bronze samples with additives of elemental graphite (GE) and pencil graphite (GP) with an average size of 10 μm in an amount of 10% vol. The wear rate of bronze samples with graphite GI is higher than with GP by 2 times when tested with mineral oil and 1.1 times when tested with synthetic oil. The jamming load is 1.5-2 times higher than bronze with GP graphite compared to bronze without graphite.
Procedures for measuring thickness of lubricating film using capacitive method on Amsler-type friction machines
Authors: Darovskoy G V , Polyakov V N , Opatskikh A N
Published: December 2020

A technique has been developed for measuring the thickness of a lubricating film by the capacitive method on Amsler-type friction machines. A diagram of the implementation of the original device for solving the problem is described, a method for its calibration is described. It was experimentally established that the applied method is highly stable in the results obtained in a wide range of measured values.
Comparative analysis of tribological properties of friction bands used in lifting and transport machinery
Authors: Kulakov O I
Published: December 2020

The comparative tests of asbestos-containing EM-1 and asbestos-free BAC friction bands were conducted. The results indicate that BAC friction bands provide more stable friction coefficients. The usage of BAC friction bands may reduce maintenance costs for the brakes of powered industrial machines.
Features of wear and friction in titanium
Authors: Pakhomov M A , Gorlov D , Stolyarov V
Published: December 2020

The characteristics of friction and wear during low-frequency reciprocating motion of the indenter in commercially pure titanium with coarse and fine grains are investigated. The role of the microstructure refining and the ratio of grain size and displacement amplitude is shown.
Simulation of contact interaction of rough surfaces
Authors: Tikhomirov V P , Izmerov M A
Published: December 2020

Using simulation of contact interaction of rough surfaces, it is possible to determine the dependence of the convergence value on the load applied to the conjugate surfaces, which will allow more accurately solve tribological problems, as well as problems of ensuring a given degree of tightness, etc.
Artificial applicability labels for improving policies in retrosynthesis prediction
Authors: Bjerrum Esben Jannik , Thakkar Amol , Engkvist Ola
Published: December 2020

Automated retrosynthetic planning algorithms are a research area of increasing importance. Automated reaction-template extraction from large datasets, in conjunction with neural-network-enhanced tree-search algorithms, can find plausible routes to target compounds in seconds. However, the current method for training neural networks to predict suitable templates for a given target product leads to many predictions that are not applicable in silico. Most templates in the top 50 suggested templates cannot be applied to the target molecule to perform the virtual reaction. Here, we describe how to generate data and train a neural network policy that predicts whether templates are applicable or not. First, we generate a massive training dataset by applying each retrosynthetic template to each product from our reaction database. Second, we train a neural network to perform near-perfect prediction of the applicability labels on a held-out test set. The trained network is then joined with a policy model trained to predict and prioritize templates using the labels from the original dataset. The combined model was found to outperform the policy model in a route-finding task using 1700 compounds from our internal drug-discovery projects.
Stable near white light emission in CsPbCl3 perovskite quantum dots by incorporating Al3+/Mn2+ ions
Authors: Padhiar Muhammad Amin , Wang Minqiang , Ji Yongqiang , Zhou Yun , Qiu Hengwei , Yang Zhi
Published: December 2020

All inorganic cesium lead halides (CsPbX3, X = Cl, Br, I) are promising materials and have been developed in recent years for various optoelectronic devices and applications because of their excellent optoelectronic properties. Regardless of their excellent characteristics their stability is still uncertain and it is challenging task to obtain stable emission in CsPbX3 perovskite quantum dots (PQDs), hence limiting their practical optoelectronic application. In this context, several approaches have been used like an-ion exchange, ion doping, and core–shell structure to enhance PQDs stability. Herein, we synthesized dual ion co-doped Al3+/Mn2+ CsPbCl3 PQDs for stable light emitting diodes through traditional hot injection method for the first time. By adjusting molar concentration of Al3+/Mn2+ CsPbCl3, co-doped PQDs were successfully prepared. The co-doped PQDs exhibit tunable emission, covering a wide range under UV excitation. Moreover, these high luminescent co-doped PQDs were used to fabricate WLEDs, displaying stable near white light emission with the chromaticity coordination at (0.35, 0.28). Some new evidence has emerged, although some aspects of Mn2+ and Al3+ doping are considered to be consistent with previous conclusions. This viewpoint incorporates all of these details and focuses on the path of transition metal ion doping to perovskite nanostructures and offers an overview for possible potential studies.
Physiological and behavioural responses of moose to hunting with dogs
Authors: Græsli Anne Randi , Le Grand Luc , Thiel Alexandra , Fuchs Boris , Devineau Olivier , Stenbacka Fredrik , Neumann Wiebke , Ericsson Göran , Singh Navinder J , Laske Timothy G , Beumer Larissa T , Arnemo Jon M , Evans Alina L
Published: December 2020

Optimal management of hunted species requires an understanding of the impacts of hunting on both individual animal and population levels. Recent technological advancements in biologging enable us to obtain increasingly detailed information from free-ranging animals, covering longer periods of time, and providing the data needed to assess such impacts. In Sweden, more than 80 000 moose are harvested annually, mostly hunted with the use of baying dogs. The effects of this hunting method on animal welfare and stress are understudied. Here, we evaluated 6 real and 17 experimental hunting approaches with baying dogs [wearing global positioning system (GPS) collars] on 8 adult female moose equipped with ruminal temperature loggers, subcutaneous heart rate (HR) loggers and GPS collars with accelerometers. The obtained data were used to analyse the behavioural and physiological responses of moose to hunting with dogs. Successful experimental approaches (moose and dog were within 240 m for >10 min) resulted in higher maximum body temperature (Tb, 0.88°C higher) and a mean increase in HR of 24 bpm in moose at the day of the approach compared to the day after. The moose rested on average >90 min longer the day after the approach compared to the day of the approach. The moose travelled on average 4.2 km longer and had a 1.3 m/s higher maximum speed the day of the approach compared to the day after. Our results demonstrate that hunting with dogs increase moose energy expenditure and resting time (and consequently decrease time available for foraging) on an individual level. This could possibly affect body condition and reproduction rates if the hunting disturbances occur frequently.
Eosinophilic heart disease: diagnostic and prognostic assessment by cardiac magnetic resonance
Authors: Antonopoulos Alexios S , Azzu Alessia , Androulakis Emmanuel , Tanking Chonthicha , Papagkikas Panagiotis , Mohiaddin Raad H
Published: December 2020

Aims 

Eosinophilic heart disease (EHD) is a rare cardiac condition with a wide spectrum of phenotypes. The diagnostic and prognostic value of cardiac magnetic resonance (CMR) in EHD remains unknown.

Methods and results 

This was a retrospective analysis of 250 patients with eosinophilia referred for a CMR scan (period 2000–2020). CMR data sets and clinical/laboratory data were collected. Patients were followed up for a mean of 24 months (range 1–224) for the composite endpoint of death, acute coronary syndrome, hospitalization for acute heart failure, malignant ventricular arrhythmias, or the need for implantable cardiac defibrillator/pacemaker. The main objectives were to explore the diagnostic value of CMR in EHD; relationships between cardiac function, late gadolinium enhancement (LGE), and EHD phenotypes; and the prognostic value of fibrosis and oedema by CMR. The prevalence of findings compatible with EHD was 39% (patients with cardiac symptoms: 57% vs. screening: 20%, P < 0.001). EHD phenotypes included subendocardial LGE (n = 58), mid-wall/subepicardial LGE (n = 26), pericarditis (n = 5) or dilated cardiomyopathy (n = 8). Myocardial oedema was present in 10% of patients. Intracardiac thrombi (7%) were associated with EHD phenotype (χ2=47.3, P = 1.3×10−8). LGE extent correlated with LVEDVi (rho = 0.268, P = 5.3×10−5) and LVEF (rho=−0.415, P = 8.6×10−11). A CMR scan positive for EHD [hazard ratio (HR) = 5.61, 95% confidence interval (CI): 1.82–17.89, P = 0.0026] or a subendocardial LGE pattern (HR = 5.13, 95% CI: 1.29–20.38, P = 0.020) were independently associated with the composite clinical endpoint.

Conclusion 

The diagnostic yield of CMR screening in patients with persistent eosinophilia, even if asymptomatic, is high. The extent of subendocardial fibrosis correlates with LV remodelling and independently predicts clinical outcomes in patients with eosinophilia.
EU transfers and euroscepticism: can’t buy me love?
Authors: Borin Alessandro , Macchi Elisa , Mancini Michele
Published: December 2020

The future of an institution, such as the European Union, ultimately depends on people’s support. This paper investigates whether EU redistributive policies have improved public attitudes towards European integration, both in terms of public opinion and political preferences. We focus on Cohesion Policy funds, whose allocation allows us to single out these effects by means of a regression discontinuity approach. The results show that EU transfers have mitigated the rise of Eurosceptical attitudes and reduced political consensus for anti-EU parties. The effects are homogeneous across different socio-economic groups, including the most disadvantaged ones. The improvement in public support for the EU does not appear to be exclusively a spillover of the positive economic effect of funding; we show evidence suggesting the existence of a ‘reciprocity-effect’ channel, that is, citizens in recipient regions recognize the beneficial role of the EU as the source of funding.
Health outcomes, personality traits and eating disorders
Authors: Ham John C , Iorio Daniela , Sovinsky Michelle
Published: December 2020

Bulimia nervosa (BN) is a detrimental persistent eating disorder that impacts millions of women, and imposes serious costs on the economy in terms of physical health, treatment costs, absence from work and reduced human capital accumulation. One important issue in treating BN is that it is often undiagnosed, especially among disadvantaged girls. The failures to diagnose BN occur, in part, because many cases of BN are unobservable to others, and asking girls about their bingeing and purging behaviour can be considered invasive. Using data on eating disorder behaviours from the National Heart, Lung, and Blood Institute Growth and Health Study, we show that information on a girl’s personality traits, along with information on her family’s socioeconomic status (SES), can be used to impute the unobservable BN behaviour. In particular, we find that personality traits are significant determinants of bulimic behaviour, even after controlling for SES. These results suggest a way to target those who are likely to suffer from BN based on identifiable personality traits. Given the costs involved in BN, and the number of individuals affected, our research suggests a practical direction for public health policy to reduce the number of undiagnosed cases.
Who does or does not use the ‘Corona-Warn-App’ and why?
Authors: Horstmann Kai T , Buecker Susanne , Krasko Julia , Kritzler Sarah , Terwiel Sophia
Published: December 2020

To slow the spread of SARS-CoV-2, the German government released the ‘Corona-Warn-App’, a smartphone application that warns users if they have come into contact with other users tested positive for SARS-CoV-2. Since using the ‘Corona-Warn-App’ is health-relevant behavior, it is essential to understand who is (and who is not) using it and why. In N = 1972 German adults, we found that non-users were on average older, female, healthier, in training and had low general trust in others. The most frequently named reasons by non-users were privacy concerns, doubts about the effectiveness of the app and lack of technical equipment.
Healthy Aging Interventions Reduce Repetitive Element Transcripts
Authors: Wahl Devin , Cavalier Alyssa N , Smith Meghan , Seals Douglas R , LaRocca Thomas J
Published: December 2020

Transcripts from noncoding repetitive elements (REs) in the genome may be involved in aging. However, they are often ignored in transcriptome studies on healthspan and lifespan, and their role in healthy aging interventions has not been characterized. Here, we analyze REs in RNA-seq datasets from mice subjected to robust healthspan- and lifespan-increasing interventions including calorie restriction, rapamycin, acarbose, 17-α-estradiol, and Protandim. We also examine RE transcripts in long-lived transgenic mice, and in mice subjected to a high-fat diet, and we use RNA-seq to investigate the influence of aerobic exercise on RE transcripts with aging in humans. We find that (a) healthy aging interventions/behaviors globally reduce RE transcripts, whereas aging and high-fat diet (an age-accelerating treatment) increase RE expression; and (b) reduced RE expression with healthy aging interventions is associated with biological/physiological processes mechanistically linked with aging. Our results suggest that RE transcript dysregulation and suppression are likely novel mechanisms underlying aging and healthy aging interventions, respectively.
Why an increase in activity of an enzyme in the Calvin–Benson cycle does not always lead to an increased photosynthetic CO2 uptake rate?—a theoretical analysis
Authors: Zhao Honglong , Tang Qiming , Chang Tiangen , Xiao Yi , Zhu Xin-Guang
Published: December 2020

Overexpressing Calvin–Benson cycle (CBC) enzyme shown to limit the flow of CO2 through the cycle is a major approach to improve photosynthesis. Though control coefficients of CBC enzymes vary under different environmental and developmental conditions, it is usually implicitly assumed that enzymes in the CBC have a monotonic impact on the CBC fluxes. Here, with a dynamic systems model of the photosynthetic carbon metabolism, we show that, for glycerate-3-phosphate kinase (PGAK), fructose-1,6-bisphosphatase (FBPase), fructose-1,6-bisphosphate aldolase (FBA) and transketolase (TKa), individually increasing activity of these CBC enzymes theoretically leads to an initial increase then decrease in the fluxes through the CBC. Also, the inhibition constants of adenosine diphosphate (ADP) for PGAK and of fructose-6-phosphate (F6P) for FBPase influence the CBC flux in a biphasic manner. These predicted enzymes showing a biphasic manner are always located in different subcycles of the CBC, which consume the shared substrates in the early steps in the CBC and produce intermediates used as substrates for enzymes in the later reactions. We show that the excessive increase in activities of enzymes in one subcycle consuming the shared metabolite could cause low concentrations of metabolites in the other subcycles, which results in low reaction rates of the later reactions and hence lowers overall CBC flux. This study provides a model to explain the underlying reasons that overexpression of enzymes in the CBC sometimes can negatively impact photosynthesis. We find that balanced activities of enzymes in the subcycles of the CBC are required to gain a higher efficiency of the CBC.
Option Prices and the Probability of Success of Cash Mergers
Authors: Bester C Alan , Martinez Victor H , Roşu Ioanid
Published: December 2020

We study both theoretically and empirically option prices on firms undergoing a cash merger offer. To estimate the merger’s success probability, we use a Markov Chain Monte Carlo (MCMC) method using a state space representation of our model. Our estimated probability measure has significant predictive power for the merger outcome even after controlling for variables used in the merger literature. As predicted by the model, a graph of the target firm’s implied volatility against the strike price has a kink at the offer price, and the kink’s magnitude is proportional to the merger’s success probability.
Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) Antibody Responses in Children With Multisystem Inflammatory Syndrome in Children (MIS-C) and Mild and Severe Coronavirus Disease 2019 (COVID-19)
Authors: Anderson Elizabeth M , Diorio Caroline , Goodwin Eileen C , McNerney Kevin O , Weirick Madison E , Gouma Sigrid , Bolton Marcus J , Arevalo Claudia P , Chase Julie , Hicks Philip , Manzoni Tomaz B , Baxter Amy E , Andrea Kurt P , Burudpakdee Chakkapong , Lee Jessica H , Vella Laura A , Henrickson Sarah E , Harris Rebecca M , Wherry E John , Bates Paul , Bassiri Hamid , Behrens Edward M , Teachey David T , Hensley Scott E
Published: December 2020

Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) antibody responses in children remain poorly characterized. Here, we show that pediatric patients with multisystem inflammatory syndrome in children (MIS-C) possess higher SARS-CoV-2 spike immunoglobulin G (IgG) titers compared with those with severe coronavirus disease 2019, likely reflecting a longer time since the onset of infection in MIS-C patients.
Curbing the COVID-19 pandemic with facility-based isolation of mild cases: a mathematical modeling study
Authors: Chen Simiao , Chen Qiushi , Yang Juntao , Lin Lin , Li Linye , Jiao Lirui , Geldsetzer Pascal , Wang Chen , Wilder-Smith Annelies , Bärnighausen Till
Published: December 2020

Background

In many countries, patients with mild coronavirus disease 2019 (COVID-19) are told to self-isolate at home, but imperfect compliance and shared living space with uninfected people limit the effectiveness of home-based isolation. We examine the impact of facility-based isolation compared to self-isolation at home on the continuing epidemic in the USA.

Methods

We developed a compartment model to simulate the dynamic transmission of COVID-19 and calibrated it to key epidemic measures in the USA from March to September 2020. We simulated facility-based isolation strategies with various capacities and starting times under different diagnosis rates. Our primary model outcomes are new infections and deaths over 2 months from October 2020 onwards. In addition to national-level estimations, we explored the effects of facility-based isolation under different epidemic burdens in major US Census Regions. We performed sensitivity analyses by varying key model assumptions and parameters.

Results

We find that facility-based isolation with moderate capacity of 5 beds per 10 000 total population could avert 4.17 (95% credible interval 1.65–7.11) million new infections and 16 000 (8000–23 000) deaths in 2 months compared with home-based isolation. These results are equivalent to relative reductions of 57% (44–61%) in new infections and 37% (27–40%) in deaths. Facility-based isolation with high capacity of 10 beds per 10 000 population could achieve reductions of 76% (62–84%) in new infections and 52% (37–64%) in deaths when supported by expanded testing with an additional 20% daily diagnosis rate. Delays in implementation would substantially reduce the impact of facility-based isolation. The effective capacity and the impact of facility-based isolation varied by epidemic stage across regions.

Conclusion

Timely facility-based isolation for mild COVID-19 cases could substantially reduce the number of new infections and effectively curb the continuing epidemic in the USA. Local epidemic burdens should determine the scale of facility-based isolation strategies.
Digital ischaemia of the upper limbs in middle age: consider arterial thoracic outlet syndrome until proven otherwise!
Authors: Al-Jundi Wissam , Park WooSup Michael
Published: December 2020

Objectives

Patients presenting with digital upper limb ischaemia are occasionally referred to rheumatology services to rule out vasculitis. We aimed to present two cases of delayed diagnosis of arterial thoracic outlet syndrome (aTOS) in middle-aged patients presenting with digital ischaemia in order to raise awareness of this important pathology that requires timely surgical intervention.

Methods

Two cases of progressive ischaemia of the right upper extremity caused by primarily undiagnosed compression of the subclavian artery by an accessory cervical rib are presented. The case notes, radiological images, intra-operative and postoperative findings for both patients were reviewed. Patients were followed up after ≥6 months to assess prognosis.

Results

Both patients had a working diagnosis of Buerger’s disease and had been treated with prostaglandin infusions before establishment of the diagnosis of arterial thoracic outlet syndrome. Both patients were heavy smokers, and one patient had bilateral symptoms and a history of axial SpA and positive HLA-B27. Late presentation in one patient led to the loss of three fingers and the need for plastic reconstructive surgery after cervical rib resection and revascularization. In the other patient, surgical thrombectomy of the upper limb arteries along with resection of a cervical rib and repair of the subclavian artery with an interposition graft were necessitated to heal digital ulcers successfully.

Conclusion

A high index of suspicion of aTOS should be maintained in middle-aged patients presenting with digital or upper limb ischaemia even in the presence bilateral symptoms or relevant risk factors of other diagnoses, such as smoking or a positive rheumatological history.
Primary Epstein–Barr Virus Infection in Healthy Children in Saudi Arabia: A Single Hospital-Based Study
Authors: Zaki Ahmed
Published: December 2020

Background

Primary Epstein–Barr virus (EBV) infection presents typically with features of infectious mononucleosis (IM) but it may present with atypical symptoms. We aim to evaluate the epidemiological, clinical and laboratory characteristics of primary EBV infection in children in western Saudi Arabia.

Methods

A retrospective analysis of the electronic data of all children who were admitted to the hospital and were tested for EBV-viral capsid antigen (VCA) IgM in the period from 1 January 2018 to 31 December 2019. All data of the children with positive EBV-VCA IgM were collected. Patients were divided into two groups; IM and the non-typical presentations groups.

Results

Fort-two patients had positive EBV-VCA IgM; 71% had IM and 29% had non-typical presentations. IM was more common in early childhood (46.7%). The non-typical presentations were more in infants below 1 year (50%). Adolescents were less affected (6.7% and 16.7%, respectively). Time to diagnose EBV in the non-typical presentations group was longer than IM group; [3.4 (3.2–4.6) vs. 4.7 (4.1–5.5), p = 0.039]. The total leucocytes count was higher in the IM syndrome group compared to the non-typical presentation group [11 (10.3–17.7) vs. 5.5 (4.5–6.4), p < 0.0001].

Conclusions

Primary EBV infection in healthy children in Saudi Arabia occurs more frequently in the younger age groups. IM syndrome occurs more frequently in early childhood. The non-typical presentation occurs more frequently in infants. While adolescents are less commonly affected by primary EBV.
Psychological and Behavioral Impact of Lockdown and Quarantine Measures for COVID-19 Pandemic on Children, Adolescents and Caregivers: A Systematic Review and Meta-Analysis
Authors: Panda Prateek Kumar , Gupta Juhi , Chowdhury Sayoni Roy , Kumar Rishi , Meena Ankit Kumar , Madaan Priyanka , Sharawat Indar Kumar , Gulati Sheffali
Published: December 2020

Background

During the current ongoing COVID-19 pandemic, psychological problems like anxiety, depression, irritability, mood swings, inattention and sleep disturbance are fairly common among quarantined children in several studies. A systematic review of these publications to provide an accurate burden of these psychiatric/behavioral problems is needed for planning mitigating measures by the health authorities.

Methods

Different electronic databases (MEDLINE, EMBASE, Web of Science, CENTRAL, medRxiv and bioRxiv) were searched for articles describing psychological/behavioral complications in children/adolescents with/without pre-existing behavioral abnormalities and their caregivers related to the COVID-19 pandemic. Only original articles with/without comparator arms and a minimum sample size of 50 were included in the analysis. The pooled estimate of various psychological/behavioral problems was calculated using a random-effect meta-analysis.

Results

Fifteen studies describing 22 996 children/adolescents fulfilled the eligibility criteria from a total of 219 records. Overall, 34.5%, 41.7%, 42.3% and 30.8% of children were found to be suffering from anxiety, depression, irritability and inattention. Although the behavior/psychological state of a total of 79.4% of children was affected negatively by the pandemic and quarantine, at least 22.5% of children had a significant fear of COVID-19, and 35.2% and 21.3% of children had boredom and sleep disturbance. Similarly, 52.3% and 27.4% of caregivers developed anxiety and depression, respectively, while being in isolation with children.

Conclusion

Anxiety, depression, irritability, boredom, inattention and fear of COVID-19 are predominant new-onset psychological problems in children during the COVID-19 pandemic. Children with pre-existing behavioral problems like autism and attention deficit hyperactivity disorder have a high probability of worsening of their behavioral symptoms.
Utilization of Advanced Practice Providers in Advanced Practice Provider-Led Stroke Clinic to Expand Outpatient Stroke Follow-up Care
Authors: Trotter Tanya Leigh , Braunlin Jeri Lynn , Crump Gail M. , Neff Julie , Schwartz Cynthia , Rotterman Meghann M. , Shields Staci
Published: December 2020

Stroke follow-up care with neurology specialty advanced practice providers is critical to focus on stroke prevention. The need for which is underscored by results of a recent study noting that many stroke survivors of first-ever strokes were not receiving stroke standard-of-care prevention measures including consistent antiplatelet therapies and regular exercise. Study findings further note the rates of usage for stroke prevention interventions (daily anti-platelet therapy, smoking cessation, regular exercise, hypertension control) were between 50% and 70%. Clinical nurse specialists along with nurse practitioner and physician assistant advanced practice providers are uniquely suited to manage outpatient ischemic stroke care to reduce the recurrence of stroke and improve patient outcomes.
SPICEMIX: Integrative single-cell spatial modeling of cell identity
Authors: Chidester Benjamin , Zhou Tianming , Alam Shahul , Ma Jian
Published: December 2020

Spatial transcriptomics technologies promise to reveal spatial relationships of cell-type composition in complex tissues. However, the development of computational methods that can utilize the unique properties of spatial transcriptome data to unveil cell identities remains a challenge. Here, we introduce SpiceMix, a new interpretable method based on probabilistic, latent variable modeling for effective joint analysis of spatial information and gene expression from spatial transcriptome data. Both simulation and real data evaluations demonstrate that SpiceMixmarkedly improves upon the inference of cell types and their spatial patterns compared with existing approaches. By applying to spatial transcriptome data of brain regions in human and mouse acquired by seqFISH+, STARmap, and Visium, we show that SpiceMixcan enhance the inference of complex cell identities, reveal interpretable spatial metagenes, and uncover differentiation trajectories. SpiceMixis a generalizable framework for analyzing spatial transcriptome data to provide critical insights into the cell type composition and spatial organization of cells in complex tissues.
An Optimized CRISPR/Cas9 Approach for Precise Genome Editing in Neurons
Authors: Fang Huaqiang , Bygrave Alexei M. , Roth Richard H. , Johnson Richard C. , Huganir Richard L.
Published: December 2020

The efficient knock-in of large DNA fragments to label endogenous proteins remains especially challenging in non-dividing cells such as neurons. We developedTargetedKnock-In withTwo-guides (TKIT) as a novel CRISPR/Cas9 based approach for efficient, and precise, genomic knock-in. Through targeting non-coding regions TKIT is resistant to INDEL mutations. We demonstrate TKIT labelling of endogenous synaptic proteins with various tags, with efficiencies up to 42% in mouse primary cultured neurons. Utilizing in utero electroporation or viral injections in mice TKIT can label AMPAR subunits with Super Ecliptic pHluorin, enabling visualization of endogenous AMPARs in vivo using two-photon microscopy. We further use TKIT to assess the mobility of endogenous AMPARs using fluorescence recovery after photobleaching. Finally, we show that TKIT can be used to tag AMPARs in rat neurons, demonstrating precise genome editing in another model organism and highlighting the broad potential of TKIT as a method to visualize endogenous proteins.