bluuebunny/crossref_metadata_2025 huggingface dataset:
Criteria Determining the Number of Estimate Points of Moment Method for Performance Functions Including Non-differentiable Points
Authors: Wang Ruotong , Yu Zhiran , Wang Junjie
Published: June 2021

Moment method is famous for its calculation efficiency. Moments of the performance function are obtained by point estimates based on Hermite Integration. The reliability index and probability of failure can be obtained using existing standardization function or existing distribution systems. The precision of moment method increases monotonously with the increasing number of estimating points. The performance functions with non-differentiable points are frequently encountered when elasto-plastic behavior dominates for a structure under loading. Thus the accuracy and efficiency of moment method should be addressed for performance functions with non-differentiable points. In this paper, an example of structural performance functions is presented to show the existence of non-differentiable points. Two example performance functions are used to verify the accuracy and efficiency of moment method. The MCS method is employed to obtain the accurate results of probability of failure. The relative errors of probability of failure from moment method are obtained through a comparison with the results from MCS method. The fluctuation of the relative errors with the number of estimate points is also presented. The required number of estimate points for performance functions with non-differentiable points is discussed through the above two examples. Finally, criteria to determine the estimate points for performance functions with non-differentiable points are proposed and verified the applicability.
Research on response characteristics of weighing sensor of mixing vessel under medium and long period surge
Authors: Zhang Yipeng , Yang Xiuli , Li Dongdong , Fan Chenyang
Published: June 2021

Under surge condition, the composite motion of heave, roll, pitch, sway and surge occurs in the concrete mixing vessel, which affects the measurement accuracy of the load cell. Taking the S-shaped load cell as the test object, the measurement accuracy of the load cell under the condition of complex force field is tested by using the six degree of freedom test platform to simulate the medium and long period surge sea conditions. The test results show that: the measured value of the load cell is affected by the sway acceleration, the surge acceleration and the heave acceleration, and is positively correlated with them; when the meaningful wave height is 1m and the average zero crossing period is 6 ∼ 10s, the direct weighing accuracy of the concrete mixing vessel can not meet the requirements of the domestic standard.
Monitoring and Analysis of Subway Shaft Construction Displacement
Authors: Rui-juan Yang , You-Sheng Deng , Tao Liu , Yun-He Sun
Published: June 2021

According to the construction site monitoring of a subway tunnel shaft in Beijing, the deformation laws of surface settlement, horizontal displacement and vertical displacement of retaining structure during shaft construction were analyzed. The results show that: firstly, the ground settlement around the shaft can be divided into two stages, the rapid settlement stage before the floor construction and the stable settlement stage after the floor construction. The settlement rate and value of the middle point of the long side of the shaft is faster and bigger than the corner point and the middle point of the short side. The settlement value first increases and then decreases with the increase of the distance to the pit side. The maximum settlement is located at (0.61 ∼ 1) times the excavation depth behind the diaphragm wall. Secondly, the horizontal deformation of the long side of diaphragm wall is obviously different from the short side. The horizontal deformation of the long side is larger than the short side, and the position of the maximum horizontal deformation is deeper than the short side. The horizontal deformation curve of the middle point of the long side has obvious inflection point, and the middle point of the short side presents reciprocating type. The variation range of horizontal displacement of diaphragm wall top is between 10 mm, and the maximum horizontal displacement is 0.037% of shaft depth. Finally, the vertical displacement of the top of the diaphragm wall settles rapidly before the excavation of the bottom plate, and the settlement value decreases gradually after the excavation, and the increase rate of the diaphragm wall settlement is the largest when it is excavated to the bottom of the shaft. This deformation law can provide reference for the optimization of support design of similar projects.
Research on the application of BDS/GIS/RS technology in the high speed railway infrastructure maintenance
Authors: Yang Jianfeng , Bai Xuejiao , Zhang Zhuoxin , Yang Meihao , Pan Peifen , Liu Tao , He Lijun , Zhang Jifeng , Tao Tao
Published: June 2021

The high-speed railway infrastructure maintenance is the key to ensure the safe operation of the railway. The technical characteristics and advantages of Beidou Navigation Satellite System (BDS), Geographic Information System (GIS), and Remote Sensing (RS) are analysed for integrated application based on the practical application of professional engineering infrastructure monitoring, equipment inspection, disaster prevention and warning, workers management and time synchronization, and the solution of intelligent monitoring system for high-speed railway infrastructure maintenance was proposed. And this system supports visual display of vector and electronic map, status query of workers, trains, equipment and infrastructure for remotely monitoring, detecting and managing, which can provide low-cost, reliable and accurate information services for the security monitoring and management of the high-speed railway infrastructure maintenance.
To the question of the dependence of the change in the speed of ultrasound and the natural frequency of vibration of atoms in monatomic planes during a polymorphic transition in iron
Authors: Yurchenko Stepan A
Published: June 2021

Iron is one of the most used metals in industry and construction. Machines and mechanisms made of iron operate over a wide range of temperatures and voltages. Checking their performance during operation is carried out using non-destructive testing. One of the methods of non-destructive testing is the method of molecular acoustics, which links the internal structure and physical and mechanical characteristics with the values of the longitudinal and transverse ultrasound velocity. The change in the speed of sound upon deformation of the material is characterized by a change in the number of defects in the crystal lattice or by the rotation of mesoscopic volumes. However, a change in the speed of ultrasound also occurs during polymorphic transformation, which is associated with a change in the geometric dimensions of the cell of the crystal lattice and can be both under the influence of temperature and under pressure. Therefore, when analyzing a material by the method of molecular acoustics, it is necessary to understand what exactly happened in the material - a polymorphic transition or an accumulation of defects. This is possible only with an accurate determination of two parameters - the natural frequency of atomic vibration, which changes during the polymorphic transition, and a change in the ultrasonic wave velocity due to a change in the interatomic interaction of atomic shells. Therefore, the main goal of this work is to derive a theoretical equation relating the change in the natural vibration frequency of atoms during the polymorphic transition of iron from aFe to yFe, with a change in the specific area per atom in the atomic plane.
Analytical study of the non-stationary temperature field of a thermally thin plate
Authors: Latypov I I , Bigaeva L A , Mukhametshina G S , Shaikhutdinova N A , Gilev A Y
Published: June 2021

The report analytically investigates the unsteady temperature field of a plate experiencing intense thermal action. The problem is reduced to solving a singularly perturbed boundary value problem of the nonstationary thermal conductivity equation with nonlinear boundary conditions on movable borders. The approximate solution of which is obtained in the form of an asymptotic decomposition of the solution in the sense of Poincaré in degrees of small parameters, depending on the proximity of the point under consideration to the borders.
Metric transformation of the surface of a tight punch for forming sheet shells of double curvature
Authors: Mikheev V A , Grechnikov F V , Alvarenga Roberto de , Bodrov V V
Published: June 2021

For the first time, the problem of parametric reduction of the circumscribing surface of the shell of double curvature to the main axes and to the planes of symmetry defined by Gaussian coordinates is considered in detail. The solution of this problem is essential for ensuring the conditions of symmetrical shaping of the double-curvature circumflex shells by tight fit. The tight punch is presented in the form of a technological electronic layout, containing metric information of the surface of double curvature and storing information of the geometric alignment of the skin that extends to the outer circumferential surface of the unit. In this case, the circumferential surface of the shell of double curvature remains invariant with respect to the coordinate transformation.
Effect of tungsten nanoparticles on interaction of Sn-Cu-Co metallic matrices with diamond
Authors: Ozolin A V , Sokolov E G , Golius D A
Published: June 2021

The effect of tungsten nanoparticles on interaction of sintered Sn-Cu-Co metallic matrices with diamond has been studied. Nanoparticles were obtained by grinding standard tungsten powder in a planetary-centrifugal mill. Commercially pure tin, copper, and cobalt powders were mixed with synthetic diamonds and the milled tungsten. Samples were shaped by static pressing in a mold and sintered in vacuum at 820°C. The sintered samples were subjected to static compression test, and hardness of the metallic matrices was measured. The structure of fractures and distribution of the elements over them were explored by the SEM and energy dispersive X-ray microanalysis methods. It has been determined that introducing tungsten nanoparticles into the composite material contributes to dispersion hardening of the metallic matrix and higher strength of its adhesion to diamond.
Review of previous Russian studies in the abrasive flow machining
Authors: Levko V A , Litovka O V , Savin D I , Terjaev N S
Published: June 2021

Abrasive flow machining (abrasive flow machining (AFM)) is increasingly used worldwide. It is used for finishing and removing surface stresses in parts, the finishing machining of which using traditional methods is difficult. By now there are a large number of publications on this topic. A special interest are the articles in which previous works on various aspects of this technology are systematized. Due to a number of reasons, there are no publications from the scientific periodicals of Russia. This article presents a review of the works of Russian researchers in modelling the machining process by abrasive flow. They are aimed at modelling the rheological characteristics of the medium and contact interactions in processing. Particular attention is paid to the machining of an abrasive flow with an aligning device, as well as parts from powder molybdenum. The purpose of this article is to acquaint the wide range of readers with the works of Russian studies in the treatment of the abrasive flow of high viscosity medium.
Methods to improve vibroacoustic characteristics of mining machines
Authors: Podgorny A I , Kudrevatykh A V , Kudrevatykh N V , Ashcheulov A S , Ashcheulova A S
Published: June 2021

At machine-building enterprises, serious attention is paid to the issue of improving the products quality. Noise and vibration are one of the main indicators that characterize the quality, comfort and reliability of machines, so the reduction of noise and vibration level is one of the most important scientific and technical problems of national engineering. Along with the economic aspects, the reduction of machine noise contributes to the ecological state improvement, as well as the working and living conditions of workers. Noise and vibration are one of the most common adverse factors that worsen working conditions in production, construction and transportation.
Development and verification of a mathematical model of heating after the metal sample transition to a liquid-solid state in the turbine blades casting process
Authors: Vdovin R A , Kyarimov R R
Published: June 2021

The paper presents the results of the development of a mathematical model of the melting zone of a discrete-continuous casting installation, and also shows the verification of the results of computer modelling obtained using the developed mathematical model. An important feature of the developed mathematical model is the ability to calculate heat fluxes and temperature fields for all elements of the technological system furnace-flask-filler-mold-metal.
Theoretical aspects of the implementation of remote monitoring and control of technological processes controlled using SoftPLC
Authors: Nikishechkin P A , Akimov A A
Published: June 2021

The presented article discusses the theoretical aspects of the implementation of remote monitoring and control of technological processes controlled using the SoftPLC. The developed software environment must meet the requirements for visualization systems: speed, ease of understanding the control process, reliability and information content.
Temperature stabilization of the angular velocity measuring device
Authors: Golikov A V , Barulina M A , Pankratova E V , Efremov M V
Published: June 2021

The article examines the possibility of using an active two-circuit thermal control system to reduce the influence of temperature disturbances on the components of the angular velocity measuring device. Special attention is devoted to the problem of temperature stabilization in fiber-optic gyroscopes mounted in the measuring device. The study of the inhomogeneous nonstationary temperature field of the angular velocity measuring device with a two-circuit reversible thermal control system on Peltier thermal batteries is carried out. Thermal and mathematical models of the considered dynamical system are constructed. Specialized software for numerical simulation has been developed, which allows calculating and visualizing real-time inhomogeneous, three-dimensional, non-stationary temperature fields of the device under conditions of complex non-stationary thermal effects of internal and external sources. It is shown that the use of a two-circuit reversible thermal control system can help to significantly reduce the influence of external non-stationary temperature disturbances on the temperature stability of fiber-optic gyroscopes in various operating conditions, such as vacuum and weightlessness. The energy consumption and the increase in the weight and size characteristics of the device are estimated.
Mathematical description of elastic mechanisms of force compensating manipulator
Authors: Ya Pyatibratov G , Altunyan L L , Danshina A A
Published: June 2021

Improvement of control systems for manipulators and robots was required implementation complex automation of production processes. It is necessary to have a reliable mathematical description of elastic mechanisms interacting during operation to solve problems of analysis and synthesis of control devices of force compensating manipulators. The work goal is the development of the mathematical description of elastic executive mechanisms of the ShBM-150M balanced manipulator. Studies have shown that low-frequency components of moved weight elastic vibrations are due to flexural deformation of a manipulator’s shoulder and arm. Inertia equivalent values of manipulator links are changed by 2.2 and 37 times during manipulator operation with a constant load value. Total flexural deformation of shoulder and arm deflection is 25 mm during changing mass per 100 kg. And parameters of the mathematical model can be changed by 11 times, which needs adaptive control use.
Direct numerical simulation of anisotropic turbulent flow for incompressible fluid
Authors: Balonishnikov A M , Kruchkova J V
Published: June 2021

Equation for small-scale velocity or pulsation is a starting point to build almost all models of turbulence. Transport equation for Reynolds stresses, dissipation rate, kinetic energy are derived from this equation, adding some assumptions about structure of terms, including in these equations. Equation for small-scale velocity can be simplified, if we assume that large – scale velocity and its gradients are constants instead of linear profile for large-scale velocity. We implemented the direct numerical simulation of this equation under the simple shear, leading to anisotropy. The nonlinear helicity terms were computed in spectral space, using the three-dimensional Fast Fourier transformation, then, the inverse Fast Fourier transformation was used to return in physical space. Aliasing terms were not removed. Four – order Runge- Kutta method was used for integration in time. Evolution of Reynolds stresses in time were computed.
Modelling of power consumption for Advanced Encryption Standard and PRESENT ciphers
Authors: Maro E
Published: June 2021

Paper presents a result of modelling by ELMO tool and measuring on hardware stand power consumption traces for encryption algorithms Advanced Encryption Standard and PRESENT. Power consumption traces for different version of AES (basic one-round AES algorithm are compared with AESMasked_R1 and MBedAES versions) and PRESENT (with various round numbers) are generated. Assessment of instructions with leaks were made by comparison power consumption traces for fixed-input and power consumption traces for random-inputs (total quantity of traces is 104). Numbers of total and potentially leakage instructions for each examined version of AES and PRESENT ciphers implementation are estimated.
Modelling and optimization of information systems with distributed databases
Authors: Ya Lvovich I , Lvovich Ya E , Preobrazhenskiy A P , Preobrazhenskiy Yu P , Choporov O N
Published: June 2021

The paper deals with the problems of modern corporate information systems. It is necessary to carry out the structural synthesis of their components. It is important that there is a choice of the required number of parallel processing in the databases, as well as the assignment of priorities for the execution of the corresponding processing conditions. On the basis of enumeration schemes, alternative variables will be introduced. When calculations are carried out using the developed models, it is possible to calculate the values of predictive estimates for each of the search steps. That is, many promising options for information and telecommunication systems are selected, with the additional inclusion of procedures for taking into account restrictions and multi-criteria.
Automated diseases detection of plant diseases in space greenhouses
Authors: Aleynikov A F , Toropov V I
Published: June 2021

To detect plant diseases in a space greenhouse, a computer vision method is proposed by counting image pixels in the space of color channels of red, green and blue. An algorithm and a program have been developed for the automated determination of the degree of fungal diseases affecting garden strawberry leaves from the transmitted images of plant leaves. The research results can be used for early diagnosis of diseases and monitoring of the functional state of greenhouse plants.
Phase equilibrium and synthesis in ionic melts of the system Li, Na, Pb || WO4
Authors: Kochkarov J A , Baysangurova A A , Bisergaeva R A
Published: June 2021

The phase diagram of a three-component system has been studied for the first time by the method of differential thermal analysis and XRF Li,Na,Pb//WO4. The coordinates of the invariant points are determined (42,5% Na2WO4, 47,5% Li2WO4, 10% Pb2WO4, 450°C), areas of crystallization of the initial components. The possibility of chemical synthesis of lead oxide tungsten bronzes in ionic melts of the studied system is shown.
Investigation of the throughput of nonlinear surge arresters using the MatLab software environment
Authors: Kuznetsov N M , Morozov I N , Smirnov S A
Published: June 2021

This work is devoted to the topical issue of researching the throughput of nonlinear surge suppressors. The article discusses various options for test installations and offers simulation models. The MatLab environment, the Simulink simulation application, was chosen as the simulation software environment. The impulse current curve was calculated, after which the tests of nonlinear arresters using rectangular pulses were carried out. The simulation results of installations for operating tests of the surge arrester were compared with the real indicators of laboratory studies for arresters of the OPNp-110 UHL1 brand.
Research of the process of crushing liquid in a swirl gas flow
Authors: Afanasenko V G , Rubtsov A V , Kulakov P A , Boev E V
Published: June 2021

Liquid spraying is a common process in the chemical, oil and gas industries. For its implementation, nozzles of various designs are used. The outflow of liquid from the nozzle leads to the fragmentation of the continuous jet into separate drops. This process depends on many factors, including the movement of the continuous phase in which spraying is carried out. This article discusses the relative motion of a liquid when it flows from a nozzle into a rotating gas flow and the conditions for re-crushing of liquid particles.
Digital multi-agent system for simulating natural fire fighting processes
Authors: Dorrer G A , Kobijzhakova S V , Yarovoy S V
Published: June 2021

A system for modeling and supporting decision-making on the use of forces and means to eliminate wildfires, based on a digital model, implemented in the software “Taiga-Analyst”, is proposed. The system works on the basis of agent-based simulation and allows you to select forces and means to fight a fire, simulate its propagation and elimination with reference to a digital terrain map using a geographic information system. The possibilities and scope of the “Taiga-Analyst” system are described. A decision-making scheme for fighting natural fires is shown, and the use of the system in the process of training fire safety specialists is described.
Mutual influence of the supports stiffness and the first natural frequency at bending vibrations of a spring-hinged beam
Authors: Mityaev A E , Kudryavtsev I V , Khomutov M P , Brungardt M V , Rabetskaya O I
Published: June 2021

This paper discusses the analytical finding of the required stiffness values of the supports, which would provide the given first natural frequency of bending vibrations for a spring-hinged beam. The solution is obtained through the support coefficient, the value of which, according to the theory of beam vibrations, connects the stiffness of the support of the beam and the value of its first vibration frequency. For this purpose, preliminary approximation of dependence of support coefficient values on a support stiffness is performed using quadratic analytical functions. In this case, the problem of determining the stiffness of the supports becomes inverse and is reduced to finding combinations of the supports stiffness values, at which there is a solution of the quadratic analytical functions for the required support coefficient and, accordingly, the required first beam frequency. Normalization of the obtained support coefficients is proposed for a more convenient estimation of their influence on the first frequency of beam vibration.
Modern web application development technologies
Authors: Dzhangarov A I , Pakhaev K K , Potapova N V
Published: June 2021

One of the key areas of modern information technology is the area of programming. Programming is the creation of various programs. If earlier it was, for the most part, about writing programs for the interaction of a user and a computer, today the applied field of programming is no longer limited to anything. These are programs for portable gadgets, medical equipment, space nanotechnology, and so on. Within the framework of this research, the work will focus on web development and specifically - on the development of a web application. This direction is quite popular, since the Internet segment has played a key role in human life. Whether it’s a government-owned company, a private enterprise, or a personal blog, having a website or application is a kind of business card. A web application is a client-server interaction model using browser software. In terms of their structure and logic of work, web applications often resemble the most common desktop solutions, but with one condition - such applications are always launched and executed in the browser.
Estimation of the minimum beam length for the static, dynamic, and stability problems
Authors: Mityaev A E , Kudryavtsev I V , Khomutov M P , Brungardt M V , Kolotov A V
Published: June 2021

The calculation results of extended elements of structures according to the theory of beam will be correct if the condition for their length is met, which, as is known, should be much more transverse dimensions. The absence of an exact relationship between the transverse dimensions and the length of the beam is caused by the characteristics of the behavior under a load of various types and shapes of cross-sections: open, closed, thin-walled, etc. In this paper, the ratio of the length of the beam to its transverse dimensions is considered, which provides correct results during its static and dynamic loading, as well as during the loss of stability. To do this, two forms of thin-walled cross-sections are selected: circular and rectangular. The problem solution was carried out both analytically and by the finite element method. The results showed that the most stringent requirements are introduced by the theory of stability, according to which the length should be 15 or more times the largest transverse dimension.
Spatial micro-variation of 3D hydrogel stiffness regulates the biomechanical properties of hMSCs
Authors: Wang Zheng , Zhu Xiaolu , Cong Xiuli
Published: June 2021

Human mesenchymal stem cells (hMSCs) are one of the most promising candidates for cell-based therapeutic products. Nonetheless, their biomechanical phenotype after in vitro expansion is still unsatisfactory, for example, restricting the efficiency of microcirculation of delivered hMSCs for further cell therapies. Here, we propose a scheme using maleimide-dextran hydrogel with locally varied stiffness in microscale to modify the biomechanical properties of hMSCs in three-dimensional (3D) niches. We show that spatial micro-variation of stiffness can be controllably generated in the hydrogel with heterogeneously cross-linking via atomic force microscopy measurements. The result of 3D cell culture experiment demonstrates the hydrogels trigger the formation of multicellular spheroids, and the derived hMSCs could be rationally softened via adjustment of the stiffness variation (SV) degree. Importantly, in vitro, the hMSCs modified with the higher SV degree can pass easier through capillary-shaped micro-channels. Further, we discuss the underlying mechanics of the increased cellular elasticity by focusing on the effect of rearranged actin networks, via the proposed microscopic model of biomechanically modified cells. Overall, this work highlights the effectiveness of SV-hydrogels in reprogramming and manufacturing hMSCs with designed biomechanical properties for improved therapeutic potential.
A gap theorem for minimal log discrepancies of noncanonical singularities in dimension three
Authors: Jiang Chen
Published: June 2021

We show that there exists a positive real numberδ>0\delta >0such that for any normal quasi-projectiveQ\mathbb {Q}-Gorenstein33-foldXX, ifXXhas worse than canonical singularities, that is, the minimal log discrepancy ofXXis less than11, then the minimal log discrepancy ofXXis not greater than1−δ1-\delta. As applications, we show that the set of all noncanonical klt Calabi–Yau33-folds are bounded modulo flops, and the global indices of all klt Calabi–Yau33-folds are bounded from above.
Temporal and spatial expression of adrenomedullin and its receptors in the porcine uterus and peri-implantation conceptuses
Authors: Paudel Sudikshya , Liu Bangmin , Cummings Magdalina J , Quinn Kelsey E , Bazer Fuller W , Caron Kathleen M , Wang Xiaoqiu
Published: June 2021

Adrenomedullin (ADM) is an evolutionarily conserved multifunctional peptide hormone that regulates implantation, embryo spacing, and placentation in humans and rodents. However, the potential roles of ADM in implantation and placentation in pigs, as a litter-bearing species, are not known. This study determined abundances of ADM in uterine luminal fluid, and the patterns of expression of ADM and its receptor components (CALCRL, RAMP2, RAMP3, and ACKR3) in uteri from cyclic and pregnant gilts, as well as conceptuses (embryonic/fetus and its extra-embryonic membranes) during the peri-implantation period of pregnancy. Total recoverable ADM was greater in the uterine fluid of pregnant compared with cyclic gilts between Days 10 and 16 post-estrus and was from uterine luminal epithelial (LE) and conceptus trophectoderm (Tr) cells. Uterine expression of CALCRL, RAMP2, and ACKR3 were affected by day (P < 0.05), pregnant status (P < 0.01) and/or day x status (P < 0.05). Within porcine conceptuses, the expression of CALCRL, RAMP2, and ACKR3 increased between Days 10 and 16 of pregnancy. Using an established porcine trophectoderm (pTr1) cell line, it was determined that 10−7 M ADM stimulated proliferation of pTr1 cells (P < 0.05) at 48 h, and increased phosphorylated mechanistic target of rapamycin (p-MTOR) and 4E binding protein 1 (p-4EBP1) by 6.1- and 4.9-fold (P < 0.0001), respectively. These novel results indicate a significant role for ADM in uterine receptivity for implantation and conceptus growth and development in pigs. They also provide a framework for future studies of ADM signaling to affect proliferation and migration of Tr cells, spacing of blastocysts, implantation, and placentation in pigs.
A high level of KLF12 causes folic acid-resistant neural tube defects by activating the Shh signaling pathway in mice†
Authors: Liu Yang , Yuan Qiong , Wang Zhilong , Ding Lijun , Kong Na , Liu Jingyu , Hu Yali , Zhang Yang , Li Chaojun , Yan Guijun , Jiang Yue , Sun Haixiang
Published: June 2021

Although adequate periconceptional folic acid (FA) supplementation has reduced the occurrence of pregnancies affected by neural tube defects (NTDs), the mechanisms underlying FA-resistant NTDs are poorly understood, and thus NTDs still remain a global public health concern. A high level of Krüppel-like factor 12 (KLF12) exerts deleterious effects on heath in most cases, but evidence for its roles in development has not been published. We observed KLF12-overexpressing mice showed disturbed neural tube development. KLF12-overexpressing fetuses died in utero at approximately 10.5 days post-coitus, with 100% presenting cranial NTDs. Neither FA nor formate promoted normal neural tube closure in mutant fetuses. The RNA-seq results showed that a high level of KLF12 caused NTDs in mice via overactivating the sonic hedgehog (Shh) signaling pathway, leading to the upregulation of patched 1, GLI-Krüppel family member GLI1, hedgehog-interacting protein, etc., whereas FA metabolism-related enzymes did not express differently. PF-5274857, an antagonist of the Shh signaling pathway, significantly promoted dorsolateral hinge point formation and partially rescued the NTDs. The regulatory hierarchy between a high level of KLF12 and FA-resistant NTDs might provide new insights into the diagnosis and treatment of unexplained NTDs in the future.
Inflammatory Bowel Disease-Associated Colorectal Cancer: Translational Risks from Mechanisms to Medicines
Authors: Porter Ross J , Arends Mark J , Churchhouse Antonia M D , Din Shahida
Published: June 2021

The cumulative impact of chronic inflammation in patients with inflammatory bowel diseases predisposes to the development of inflammatory bowel disease-associated colorectal cancer [IBD-CRC]. Inflammation can induce mutagenesis, and the relapsing–remitting nature of this inflammation, together with epithelial regeneration, may exert selective pressure accelerating carcinogenesis. The molecular pathogenesis of IBD-CRC, termed the ‘inflammation–dysplasia–carcinoma’ sequence, is well described. However, the immunopathogenesis of IBD-CRC is less well understood. The impact of novel immunosuppressive therapies, which aim to achieve deep remission, is mostly unknown. Therefore, this timely review summarizes the clinical context of IBD-CRC, outlines the molecular and immunological basis of disease pathogenesis, and considers the impact of novel biological therapies.
Bumblebee (Hymenoptera: Apidae) Visitation Frequency Drives Seed Yields and Interacts with Site-Level Species Richness to Drive Pollination Services in Sunflower
Authors: Thapa-Magar Khum Bahadur , Davis Thomas Seth
Published: June 2021

Understanding whether pollinator behaviors and species richness drive crop yields is a key area of investigation in pollination ecology. Using sunflower as a study species we describe variation in mean floral visitation times among bee taxa and test how interactions between bee richness and the proportion of bumblebees in localized communities impact seed yield. Seven bee genera commonly visited sunflower including Agapostemon, Bombus, Halictus, Lasioglossum, Megachile, Melissodes, and Svastra. Mean visitation times to sunflower varied across genera and Bombus and Halictus spp. spent the most time foraging on inflorescences, but the number of visits by Bombus spp. was the only parameter associated with increased yields. Experimental pollination deficit reduced seed development and yields, and these effects were stronger in stands of wild-type sunflower in the field compared to a confection variety grown in the greenhouse. Relationships between bee richness and pollination services differed for potted and wild sunflower: when bees had short-term access to potted sunflower, bee richness and relative Bombus abundances were not associated with pollination quotients. When bees had long-term access to wild sunflower, relative Bombus abundances predicted pollination services but were modified by site-level bee richness: as richness increased, the effects of Bombus abundance decreased. Our studies demonstrate that bee species richness is not always a clear predictor of pollination services; instead, our results underscore the importance of specific taxa when species richness is low (here, bumblebees), and show that the effects of bee functional groups important for pollination may be modified by changes in site-level species richness.
Human Rights and Resort to Force: Introduction to the Symposium
Authors: Akande Dapo , Johnston Katie A
Published: June 2021

While the relationship between the jus in bello and international human rights law has been the subject of considerable debate, less attention has been paid to the relationship between the jus ad bellum and human rights. The United Nations Human Rights Committee’s General Comment 36 on the right to life, adopted on 30 October 2018, brought these questions to the fore with the Committee’s pronouncement that ‘States parties engaged in acts of aggression as defined in international law, resulting in deprivation of life, violate ipso facto article 6 of the Covenant’. The contributions in this Symposium assess three ways of viewing the relationship between the protection of human rights and resort to force. First, the suggestion that resort to force in violation of the jus ad bellum will amount to a violation of the right to life is explored. Second, some contributions examine different arguments as to whether international law permits, justifies or excuses resort to force to protect human rights, and indeed whether it can change to permit such. Third, one contribution examines whether the crime of aggression, as defined in the ICC Statute, covers resort to force to protect human rights.
Prevalence and extent of coronary artery calcification in the middle-aged and elderly population
Authors: Gerke Oke , Lindholt Jes S , Abdo Barzan H , Lambrechtsen Jess , Frost Lars , Steffensen Flemming Hald , Karon Marek , Egstrup Kenneth , Urbonaviciene Grazina , Busk Martin , Mickley Hans , Diederichsen Axel C P
Published: June 2021

Aims

Coronary artery calcification (CAC) measured on cardiac computed tomography (CT) is an important risk marker for cardiovascular disease (CVD) and has been included in the prevention guidelines. The aim of this study was to describe CAC score reference values in the middle-aged and elderly population and to develop a freely available CAC calculator.

Methods and results

All participants from two population-based cardiac CT screening cohorts (DanRisk and DANCAVAS) were included. The CAC score was measured as a part of a screening session. Positive CAC scores were log-transformed and non-parametrically regressed on age for each gender, and percentile curves were transposed according to proportions of zero CAC scores. Men had higher CAC scores than women, and the prevalence and extend of CAC increased steadily with age. An online CAC calculator was developed, http://flscripts.dk/cacscore. After entering sex, age, and CAC score, the CAC score percentile and the coronary age are depicted including a figure with the specific CAC score and 25%, 50%, 75%, and 90% percentiles. The specific CAC score can be compared to the entire background population or only those without prior CVD.

Conclusion

This study provides modern population-based reference values of CAC scores in men and woman and a freely accessible online CAC calculator. Physicians and patients are very familiar with blood pressure and lipids, but unfamiliar with CAC scores. Using the calculator makes it easy to see if a CAC value is low, moderate, or high, when a physician in the future communicate and discusses a CAC score with a patient.
Walk/Wheelability: An Inclusive Instrument Pair for Participatory Age-Friendly Research and Practice
Authors: Gan Daniel R Y , Mahmood Atiya , Routhier François , Mortenson W Ben
Published: June 2021

Background and Objectives

Recent critical evaluations of age-friendly efforts have highlighted the need to prioritize the disenfranchised, including people with mobility limitations. This article examines the validity of a 13-item Stakeholders Walkability/Wheelability Audit in Neighborhoods (SWAN13) scale to measure the “walk/wheelability” of street segments from the perspectives of people with mobility limitations.

Research Design and Methods

Data were drawn from preliminary studies of the SWANaudit which was conducted in 2 Canadian metropolitan areas. Sixty-one participants who use mobility devices (e.g., walkers, power wheelchairs) and older adults from community organizations audited 195 street segments. We factor analyzed the data from their audits.

Results

SWAN13 has a 1-factor structure. 13 items were retained from 85 SWANaudit items. SWAN13 encompassed both physical and social aspects of walk/wheelability. The alpha for the scale was .79. Convergent validity was found with the University of Alabama Life-Space Assessment (ρ = .22, p = .003), especially at the neighborhood level (ρ = .23, p = .002). Significant correlation was also found with subjective assessments of a priori walk/wheelability domains (ρ = .63, p < .001).

Discussion and Implications

Walk/wheelability affects the life space of older adults and people with mobility limitations. It is an important latent variable that should be addressed to promote well-being and social participation. SWAN13 may be used in city-wide surveys to identify neighborhoods that may require age-friendly interventions from mobility perspectives. Detailed audits and interventions may be carried out in tandem using the paired SWANaudit instrument. Walk/wheelability is an inclusive and measurable concept that accounts for the needs of people with various mobility needs.
Utilizing Deep Learning to Analyze Whole Slide Images of Colonic Biopsies for Associations Between Eosinophil Density and Clinicopathologic Features in Active Ulcerative Colitis
Authors: Vande Casteele Niels , Leighton Jonathan A , Pasha Shabana F , Cusimano Frank , Mookhoek Aart , Hagen Catherine E , Rosty Christophe , Pai Reetesh K , Pai Rish K
Published: June 2021

Background

Eosinophils have been implicated in the pathogenesis of ulcerative colitis and have been associated with disease course and therapeutic response. However, associations between eosinophil density, histologic activity, and clinical features have not been rigorously studied.

Methods

A deep learning algorithm was trained to identify eosinophils in colonic biopsies and validated against pathologists’ interpretations. The algorithm was applied to sigmoid colon biopsies from a cross-sectional cohort of 88 ulcerative colitis patients with histologically active disease as measured by the Geboes score and Robarts histopathology index (RHI). Associations between eosinophil density, histologic activity, and clinical features were determined.

Results

The eosinophil deep learning algorithm demonstrated almost perfect agreement with manual eosinophil counts determined by 4 pathologists (interclass correlation coefficients: 0.805–0.917). Eosinophil density varied widely across patients (median 113.5 cells per mm2, interquartile range 108.9). There was no association between eosinophil density and RHI (P = 0.5). Significant differences in eosinophil density were seen between patients with Montreal E3 vs E2 disease (146.2 cells per mm2 vs 88.2 cells per mm2, P = 0.005). Patients on corticosteroids had significantly lower eosinophil density (62.9 cells per mm2 vs 124.1 cells per mm2, P = 0.006). No association between eosinophil density and biologic use was observed (P = 0.5).

Conclusions

We developed a deep learning algorithm to quantify eosinophils in colonic biopsies. Eosinophil density did not correlate with histologic activity but did correlate with disease extent and corticosteroid use. Future studies applying this algorithm in larger cohorts with longitudinal follow-up are needed to further elucidate the role of eosinophils in ulcerative colitis.
The Ties that Stick: Challenges and Future Promise in the Field of Bioadhesives
Authors: Burns Mercedes , Stellwagen Sarah D
Published: June 2021

Synopsis

Bioadhesives are wet or dry polymeric compounds that rely upon physical and chemical properties to generate characteristic sticky forces. The past decade has seen a rapidly evolving field of research around the functions, genetics, biochemistry, and mimetics of bioadhesives, but challenges unique to this research area continue to arise. We polled the presenters of SICB Symposium #8 to describe the “Ties that Stick:” challenges and exciting prospects that most resonated with their research pursuits. Themes that emerged from the poll included difficulties working with adhesive-producing organisms, field inherent knowledge gaps in theoretical modeling, molecular interactions, technology, and the interdisciplinary rigor of the bioadhesives field. We address each challenge with a discussion of the opportunities and applications presented by bioadhesives research.
Drought adaptability of phreatophytes: insight from vertical root distribution in drylands of China
Authors: Wang Tian-Ye , Wang Ping , Wang Ze-Lin , Niu Guo-Yue , Yu Jing-Jie , Ma Ning , Wu Ze-Ning , Pozdniakov Sergey P , Yan Deng-Hua
Published: June 2021

Aims

The vertical distribution of plant roots is a comprehensive result of plant adaptation to the environment. Limited knowledge on fine vertical root distributions and complex interactions between roots and environmental variables hinders our ability to reliably predict climatic impacts on vegetation dynamics. This study attempts to understand the drought adaptability of plants in arid areas from the perspective of the relationship between vertical root distribution and surroundings.

Methods

By analyzing root profiles compiled from published studies, the root vertical profiles of two typical phreatophytes, Tamarix ramosissima and Populus euphratica, and their relationships with environmental factors were investigated. A conceptual model was adopted to link the parameter distribution frequency with plant drought adaptability.

Important Findings

The strong hydrotropism (groundwater-dependent) and flexible water-use strategy of T. ramosissima and P. euphratica help both species survive in hyperarid climates. The differences in the developmental environments between T. ramosissima and P. euphratica can be explained well by the different distribution characteristics of root profiles. That is, higher root plasticity helps T. ramosissima develop a more efficient water-use strategy and therefore survive in more diverse climatic and soil conditions than P. euphratica. We conclude that the higher variation in root profile characteristics of phreatophytes can have greater root adaptability to the surroundings and thus wider hydrological niches and stronger ecological resilience. The inadequacy of models in describing root plasticity limits the accuracy of predicting the future response of vegetation to climate change, which calls for developing process-based dynamic root schemes in Earth system models.
BNT162b2 Vaccine Effectiveness in Preventing Asymptomatic Infection With SARS-CoV-2 Virus: A Nationwide Historical Cohort Study
Authors: Zacay Galia , Shasha David , Bareket Ronen , Kadim Itai , Hershkowitz Sikron Fabienne , Tsamir Judith , Mossinson David , Heymann Anthony D
Published: June 2021

Background

There is strong evidence regarding the efficacy and effectiveness of the BNT162b2 vaccine in preventing symptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There is a relative paucity of data regarding its effectiveness in the prevention of asymptomatic infection.

Methods

In this real-world observational study, we identified a subpopulation of individuals in a large health maintenance organization who were repeatedly tested for SARS-CoV-2 infection by polymerase chain reaction (PCR). We included these individuals in the study cohort and compared those who were vaccinated with BNT162b2 mRNA vaccine to unvaccinated individuals. A positive SARS-CoV-2 PCR test result was used as the outcome. The follow-up period was from January 1, 2021, until February 11, 2021.

Results

A total of 6286 individuals were included in the cohort. Seven days after the second vaccine dose, a rate of 6 positive PCR tests per 10 000 person-days was recorded, compared with a rate of 53 positive tests per 10 000 person-days for the unvaccinated group. The estimated vaccine effectiveness against infection with SARS-CoV-2 virus after 2 vaccine doses was 89% (95% CI, 82%–94%). The estimated effectiveness 2 weeks after the first vaccine dose was 61% (95% CI, 49%–71%).

Conclusions

In this study, vaccination with BNT162b2 reduced infection rates among individuals who underwent screening by frequent SARS-CoV-2 PCR testing. Using a cohort of frequently tested individuals reduced the indication bias for the PCR testing, which enabled estimation of infection rates.