bluuebunny/crossref_metadata_2025 huggingface dataset:
AlGaN/GaN superlattice-based multichannel RF transistors for high linearity and reliability: a simplified simulation approach
Authors: Kumar Akhil S , Uren Michael J , Parke Justin , Henry H George , Howell Robert S , Kuball Martin
Published: May 2023

Multichannel RF power amplifiers offer high frequency operation, high current and RF power, combined with excellent linearity. 3D and 2D simulation is used to investigate how changes in device architecture impact both the linearity and off-state reliability, allowing an improved linear design which does not compromise reliability. Linearity is assessed by extraction of

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, and third order intercept (TOI) as a function of gate bias, using a straightforward 2D approximation which is computation time and resource efficient compared to the full 3D simulation normally used for these devices. Off-state reliability is assumed to be linked to dielectric failure, and hence peak electric field as a measure of reliability is evaluated at gate corners and edges using a full 3D simulation. It is found that introducing a channel number-dependent doping in the AlGaN/GaN-based superlattice structure can be used to enable an improved transconductance–linearity. It is also found that there is a strong increase in TOI as gate dielectric thickness or fin width is increased. On the other hand, in order to maintain reliability, increased fin height is found to be essential in order to reduce electric field as dielectric thickness is increased. Finally, a device architecture for improving linearity, power and reduced OFF-state field is suggested.
Performance review of the joints for the ITER poloidal field coils
Authors: Breschi M , Cavallucci L , Adeagbo H , Sedlak K , Bajas H , Vostner A , Ilyin Y
Published: May 2023

For large scale magnets wound with cable-in-conduit conductors, the safe operation of the joints is of paramount importance to guarantee adequate reliability and stability margin of the whole magnet. For this reason, during the R&D activities undertaken for the development of the ITER magnet system, several experimental campaigns were launched to study the AC and DC performance of the joint and limit the risk of thermal runaways at the joints during the tokamak operation. The joint electrical resistance must be limited below specified values to avoid excessive heating generated by the transport current. Moreover, in presence of time-varying fields, different types of losses arise at the joints, which can be associated to their superconducting and resistive parts. The relative importance of these losses depends on the joint manufacturing solution. The aim of this investigation is to analyze the performance at different working conditions of the joints for the connection of the conductors of the poloidal field (PF) coils of the ITER magnet system. This work presents, for the first time, a wide review of the test campaign performed from 2016 to 2021 on the PF joint samples during the three manufacturing phases, namely pre-qualification, qualification and production. The values of electrical resistances and losses under sinusoidal field variations are reported in the paper at different operating conditions, thus building a useful database to assess the joint performances during the machine operation. The data here collected show the impact of the manufacturing techniques on the joint performances and, furthermore, represent a useful tool for the validation of numerical and analytical models of joints.
Augmentation for unmanned aerial vehicle position estimation using MARG and optical flow sensors
Authors: Li Xiang , He Fei , Xu Qing
Published: May 2023

The optical flow sensor can detect the movement of the unmanned aerial vehicle (UAV) on the ground; thus, it is widely used for UAV flight control. The commonly used pinhole model of optical flow sensor describes the optical flow measurement in linear and angular velocities. It is not suitable in the case of discrete-time processing. A novel measurement model for the optical flow sensor is proposed, which directly gives the relationship between the optical flow and the UAV’s translational/angular motions in each sampling period. A data fusion scheme based on cubature transform is also presented, which can augment UAV’s position estimation using optical flow data. The proposed method is proven to be effective through flight tests on UAVs.
Study on a circular surface fitting algorithm
Authors: Lu Zhibing , Qin Yan , Xue Yuqing , Si Zhuang , Li Yanxia , Sun Weiwei
Published: May 2023

Surface fitting techniques are becoming more and more widely used in today’s industry. To make up for the lack of accurate representation of circular holes in circular surfaces in current surface fitting algorithms, this paper improved the original algorithm based on the nonuniform rational B-sample surface fitting by referring to the form of polar coordinates in the step of parameter direction determination to make it more accurate in fitting circular surfaces. Finally, by comparing the traditional method with the improved algorithm in this paper through experimental fitting, the accuracy and practicality of the algorithm can be shown from the results.
Effect of texturing region on friction properties of journal bearings at different rotational speeds
Authors: Wang Suhua , Zhou Zhipeng
Published: May 2023

The effect of texturing area on the friction properties of partially textured bearing at different rotational speeds was investigated theoretically. Four texturing configurations are limited on the bearing surface from the oil film fracture zone of the smooth bearing (200º to 360º) in the rotational direction with different eccentricity ratios. The results show that the friction coefficient of the partially textured bearing can be reduced compared with the smooth bearing. The friction coefficient decreases greater with the increasing texture depth at the fixed rotational speed. When the texturing configuration starts from the oil film fracture zone at the eccentricity ratio of 0.4 or 0.6, the partially textured bearings perform better at different speeds.
Study on “decoupling” of inerter
Authors: Wang Chang
Published: May 2023

The braking device is regarded as the core of the vehicle deceleration, and it also does great help to the stability and reliability of the vehicle. The disc brake is one of the most important brake devices, and its main structure contains a brake disc and a friction block. The working principle is to provide the normal pressure to the friction block through the clamp, and through the friction between the friction block and the brake disc to achieve deceleration and parking. In this process, the vehicle may produce sharp noise, and the unreasonable design may lead to braking instability and noise. Therefore, it is of great engineering value and practical significance to study the dynamic characteristics of disc brakes, add new structures, and put forward the method of system parameter optimization. The main content of this paper is to study the modal coupling in the braking process and optimize it with the mechanical structure with an inerter.
Structure Cursor Fixing and Splicing Based on Cooperative Robot
Authors: Xu Jingwen , Gao Xingyu
Published: May 2023

In the field of machine vision, surface structured light image stitching can generate high-resolution images with large field of view, which can meet the needs of enterprise production. This paper introduces a 3D image Mosaic method based on robot arm and fringe projection technology. In this method, a surface structured light vision sensor installed at the end of the manipulator is used to scan and reconstruct the workpiece surface. The sensor consists of a DLP projector and a 3D camera. A set of sinusoidal structured light is projected at the measurement position, which is synchronously collected by the camera. The collected image is de-phased by using the principle of four-step phase shift and multi-frequency heterodyne to obtain 3D information. The coarse positioning algorithm of the manipulator is used to splice part of the acquired 3D information, and finally the complete 3D point cloud data on the surface of the workpiece to be measured is obtained. The experimental results show that the method can effectively and quickly obtain the 3D surface information of the car model, with strong stability and high accuracy.
Design and simulation of micro piezoelectric fiber triaxial acceleration sensor
Authors: Xu Haotian , Wang Yan , Zhou Zhenzhao , Xu Jinyong
Published: May 2023

Aiming at the demand for passive sonar systems for medium and low-frequency detection, low cost, and small working platform working sensor, a three-axis pressure piezoelectric accelerometer based on piezoelectric ceramic fiber is designed. Firstly, based on the acoustic vibration pick-up principle and extended Hamilton, the action mode of the accelerometer is analyzed theoretically to determine the accelerometer structure size. The accelerometer with a special mass structure is designed by using axially polarized piezoelectric ceramic fiber. The characteristic frequency and frequency domain analysis of the accelerometer are simulated by the FEM method. The results show that the overall size of the piezoelectric accelerometer is 20 mm ×20 mm×35 mm, the first-order natural frequency is 410 Hz, the external field directivity is standard “8” type, and the acceleration sensitivity reaches 112.2 mV/g, which verifies the great potential of the three-axis accelerometer designed by piezoelectric ceramic fiber material in the field of medium and low frequency.
Research on PID Control Strategy of Power Head Propulsion System of Engineering Hydraulic Drilling Rig
Authors: Li Yuanzhou , Liu Zhong , Xiong Zhonggang , Chen Zhong , Cai Jinyun
Published: May 2023

A mechanical model of the synchronous hydraulic system of the propulsion mechanism is established by taking the power head propulsion system of an engineering hydraulic drilling rig as the research subject. A master-slave regulation method based on the PID control strategy is proposed for the displacement deviation of two synchronous cylinders under the disturbance of external force. The method controls the synchronous accuracy of the two propulsion cylinders. Joint modeling and simulation with AMEsim and MATLAB are used to investigate the control performance of this synchronously controlled hydraulic cylinder under the disturbance of external forces. The results show that the system is subjected to an external load and cylinder 1 stabilizes after t=0.17s, and the synchronous control error between cylinder 1 and the expected value is 0.0005m. The stabilization error between cylinder 2 and cylinder 1 is 0.0006m; the power head propulsion system achieves the accuracy required for engineering construction and meets the working requirements of the engineering hydraulics drilling rig for the power head propulsion system.
Research and Implementation of CMC Chip Intelligent Control for Multi-axis Robot
Authors: Guo Qing , Gao Xingyu , Ning Lihua , Wang Ying , Chen Jianfei
Published: May 2023

Robot technology and professional technology in various fields are integrated across fields, and robots permeate all aspects of human life. As an important part of industrial robot control, intelligent motion control technology has always been a research hotspot. This paper introduces the design characteristics of CMC (Control Module on Chip), and expounds the interpolation algorithm of the point-by-point comparison method. On this basis, the multi-axis robot device is designed.
Research on crack detection method of anvil based on eddy current sensor
Authors: Gao Tao , Zhang Jinkui , Lu Guofu , Zhang Yinghong
Published: May 2023

In the process of synthetic diamond, as a key component of high-temperature and high-pressure devices, the crack of the six-sided press anvil is easy to cause serious safety accidents. This paper introduces a crack detection method based on an eddy current sensor. Through the detection system, the induced voltage value in the receiving coil is obtained when the hammer has cracks, so as to judge whether there are cracks in the hammer. The results show that when there is a crack in the anvil, the induced voltage in the receiving coil will increase significantly. When the crack length, width, and depth increase, the induced voltage in the receiving coil will increase significantly. It is proved that eddy current testing is feasible in anvil detection.
Research on Deformation Mechanism of High-Performance TC4 Alloy by near net shape manufacturing
Authors: Kang Limei , Zheng Jianming , Xian Bingchuan , Pang Xing
Published: May 2023

In this paper, we prepared titanium alloy through near-net forming green manufacturing, and then we quantitatively deformed the alloy and finally analyzed the deformation and fracture mechanism of the alloy. The result indicates that the deformation mechanism of those containing α + β lamellar structures is different from that of traditional structures. Especially, the lamellar structure can absorb the deformation energy of the alloy, thus improving the comprehensive properties of the alloy, of which the α phase mainly contributes to the plasticity of the alloy, while the β phase mainly contributes to the strength of the alloy. The two-phase combination will improve the mechanical properties of the alloy, which is completely different from the traditional strengthening mechanism of the basket structure and Widmanstatten structure.
An Ultrasonic Target Identification System Based on Piezoelectric Micromachined Ultrasonic Transducers
Authors: Gao Mingze , Wu Zhipeng , Tong Zhihao , Zhang Zhenghu , Lou Liang
Published: May 2023

In this paper, an ultrasonic target identification system based on Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) is proposed to improve the productivity efficiency of industrial production. The proposed system can accurately identify targets of different shapes. Two pieces of 3 × 3 PMUTs arrays with a resonant frequency of 115 kHz are used as the transmitter and receiver of the PMUTs-based ultrasonic sensor. The sensor is small in size and has high instability. In addition, the PMUTs based ultrasonic sensors have lower environmental requirements than vision sensors and are less expensive than laser sensors. Therefore, the sensors are suitable for large-scale use in industry. The characteristics of the proposed system are investigated in the shape experiments on the square, circle, frame, and ring targets. The four kinds of targets are acrylic plates with a thickness of 5mm. The experimental results show that the system can accurately identify the shapes of the four targets through the grid-based scheme. Besides, the identification process is automatically completed by the 3D mobile platform. The proposed system has demonstrated a cost-effective method to identify targets of different shapes, which can more efficiently guide the robotic manipulator’s grasping and other behaviors.
Error Analysis and Accuracy Optimization for the Hand-eye Calibration of Line Structured Light
Authors: Lu Yuwei , Zhang Jianguang , Yin Lizhao , Luo Jie , Dai Wei , Qin Shilin
Published: May 2023

The rapid development of machine vision technology in recent years has resulted in applications in engineering scenarios such as weld tracking, visual measurement, and precision gripping. Focusing on the fundamental steps of applying machine vision technology, the “hand-eye calibration” process is analyzed based on scenarios with a line-structured light camera and calibration ball. We found out that noise and camera pose are the main sources of calibration error. To address these issues, an improved K-medoids noise pre-processing algorithm and a camera shooting attitude control scheme are proposed and applied. The experimental results showed that when the radius of the tangent circle/radius of the calibration sphere approximates 0.618, the root means a square error of the repeatability accuracy of hand-eye calibration could be controlled within 0.23 mm, which fully meets the application requirement. Considering the low cost of line-structured light cameras, the findings of this study contribute to the large-scale diffusion of machine vision technology in engineering practices.
Inverse kinematics and singularity analysis of a redundant parallel robot
Authors: Li Jun , Liao Bin
Published: May 2023

The 3C (computer, communications, consumer electronics) industry belongs to labor-intensive and the requirements of the 3C industry are precisely high. The parallel robot is a good choice to replace human labor to manufacture these products. This paper presents a new 3-

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redundant parallel mechanism for 3C manufacturing. Firstly, some advantages of redundant parallel robots in the current industrial demand are discussed. Then, the inverse kinematics of the redundant parallel manipulator is analyzed according to the closed-loop equation, the inverse displacement problem is solved. The machine is simple and low cost, and as a less freedom robot, it has a higher precision than the traditional robot and has a broad prospect for 3C manufacturing. Finally, the Jacobian matrix of the redundant parallel manipulator was calculated and established by the inverse kinematics formula, and three kinds of the singularity of the mechanism were analyzed by the Jacobian matrix, which are the forward singularity, reverse singularity, mixed singularity respectively.
Observation on the bias current variation of a single mask triple GEM chamber
Authors: Chatterjee S. , Sen A. , Paul R. , Sahai S. , Das S. , Biswas S.
Published: May 2023

Gas Electron Multiplier (GEM) detector, one of the advanced members of the Micro Pattern
Gas Detector (MPGD) group, is widely used in High Energy Physics (HEP) experiments. The high rate
handling capability and spatial resolution make it a desired tracking detector for high rate HEP
experiments. Investigation of the long-term stability is an essential criterion for any tracking
device used in HEP experiments. To investigate the long-term stability of a Single Mask (SM)
triple GEM detector prototype, it is irradiated continuously using a 55Fe X-ray source of
energy 5.9 keV. The chamber is operated with Ar/CO2 gas mixture in continuous flow mode. The
gain and energy resolution of the chamber are calculated from the 5.9 keV X-ray peak and studied
as a function of time. The applied voltage, divider current and also the environmental parameters
(ambient temperature, pressure and relative humidity) are recorded continuously. It is observed
that at a fixed applied voltage, the divider current of the detector is changing with time and as
a result, the gain of the detector also changes. A systematic investigation is carried out to
understand the probable reasons behind the observed variation in divider current and also to find
its possible remedies. The details of the experimental setup, methodology and results are
discussed in this article.
Damage identification in concrete under impact loading at varying temperatures using voltage strain relations technique: an experimental and numerical study
Authors: Singh Indrajeet , Dev Nirendra , Pal Shilpa
Published: May 2023

Impact-loaded concrete structures cause severe and rapid damage, resulting in significant property and human life loss. As the temperature rises, the damage caused by impact loading becomes increasingly severe. Concrete structures need structural health monitoring (SHM) to avoid this damage and loss. In this study, the voltage strain relation technique was used to identify the damaged state of concrete under impact loads at various temperature conditions experimentally and numerically. For this purpose, an experimental study was performed on concrete cube specimens in which different piezo configurations (surface bonded, non-bonded, and jacketed) were installed to acquire the voltage data. Before applying an impact load to the top surface of the concrete specimen, it was preheated at 50 °C, 100 °C, and 150 °C to provide the temperature effect, and then a free-falling iron ball was dropped from 3 m heights on the top of the specimens. Furthermore, finite element analysis has been carried out to validate the experimental results with analytical results. The experimental results show that the voltage strain relation technique is well capable of detecting the damage in concrete under the temperature and impact loading conditions. The maximum absolute voltage value (Vp) of 17.11 V was recorded for the jacketed sensors under an impact height of 3 m at 100 °C. All the piezo sensor configurations are capable of finding the damage. Jacketed sensors are more efficient in the health assessment of concrete in terms of voltage strain relations. In terms of strain values, the analytical results are in good agreement with the experimental results.
Synthesis of silver nanoparticles from natural derived embelin compound and their uses in mercury degradation under solar light
Authors: Rajalakshmi T Uma , Sheeba Helen , Doss A , Veerabahu Ramyadevi , Sivagnanam Ananthi , Alfarraj Saleh , Alharbi Sulaiman Ali , Subbiah Jeeva , Mariselvam R
Published: May 2023

The present study deals with the isolation of embelin compound from Embelia ribes (Burm f). The isolated compounds were confirmed by UV/Vis spectrophotometer, 1H NMR and 13C NMR spectra. In absorption at 275 nm in UV/Vis spectra, peak range at 5.7ppm in 1H NMR and peak value at 28.52, 29.35, 31.73ppm in 13C NMR to confirmed the isolated compound are embelin. This isolated compound used as a reducing agent for silver nanoparticles synthesis. The synthesized En-AgNPs were morphologically and structurally confirmed by UV/Vis spectrophotometer, FT-IR, SEM, EDAX, and XRD. The synthesized silver nanoparticles are spherical in shape with the size of <100 nm. The embelin based silver nanoparticles used to degrade the toxic metal like Mercury under solar light. The toxic metal Mercury was degraded within 60 min by En-AgNPs under solar photo catalytic degradation.
New nanocomposite membranes based on polybenzimidazole with improved fuel cell performance at high temperatures
Authors: Hooshyari Khadijeh , Karimi Mohammad Bagher , Beydaghi Hossein , Su Huaneng , Ben Alireza Salimi
Published: May 2023

In this work, proton exchange membranes based on polybenzimidazole (PBI) with incorporation of acidic Fe3O4@SiO2@RF (resorcinol–formaldehyde)–SO3H nanoparticles are produced. The effects of the core@double-shell nanoparticles on the fuel cell performance of the PBI membrane are examined. The obtained results demonstrate that the proton conductivity of the PBI-Fe3O4@SiO2@RF–SO3H nanocomposite membranes increases. The interactions of Fe3O4@SiO2@RF–SO3H nanoparticles in the PBI matrix (which contains phosphoric acid) have strong effects on proton conductivity. The best proton conductivity of 170 mS cm−1is obtained in the nanocomposite membrane at 180 °C. The potential for the use of these nanocomposite membranes with improved fuel cell performance in high-temperature applications is confirmed.
Compression and information entropy of binary strings from the collision history of three hard balls
Authors: Vedak M , Ackland G J
Published: May 2023

We investigate how to measure and define the entropy of a simple chaotic system, three hard spheres on a ring. A novel approach is presented, which does not assume the ergodic hypothesis. It consists of transforming the particles’ collision history into a sequence of binary digits. We then investigate three approaches which should demonstrate the non-randomness of these collision-generated strings compared with random number generator created strings: Shannon entropy, diehard randomness tests and compression percentage. We show that the Shannon information entropy is unable to distinguish random from deterministic strings. The Diehard test performs better, but for certain mass-ratios the collision-generated strings are misidentified as random with high confidence. The zlib and bz2 compression algorithms are efficient at detecting non-randomness and low information content, with compression efficiencies that tend to 100% in the limit of infinite strings. Thus ‘compression algorithm entropy’ is non-extensive for this chaotic system, in marked contrast to the extensive entropy determined from phase-space integrals by assuming ergodicity.
Quantum advantage of Monte Carlo option pricing
Authors: Udvarnoki Zoltán , Fáth Gábor , Fogarasi Norbert
Published: May 2023

Quantum computers have the potential to provide quadratic speedup for Monte Carlo methods currently used in various classical applications. In this work, we examine the advantage of quantum computers for financial option pricing with the Monte Carlo method. Systematic and statistical errors are handled in a joint framework, and a relationship to quantum gate error is established. New metrics are introduced for the assessment of quantum advantage based on sample count and optimized error handling. We implement and analyze a Fourier series based approach and demonstrate its benefit over the more traditional rescaling method in function approximation. Our numerical calculations reveal the unpredictable nature of systematic errors, making consistent quantum advantage difficult with current quantum hardware. Our results indicate that very low noise levels, a two-qubit gate error rate below 10−6, are necessary for the quantum method to outperform the classical one, but a low number of logical qubits (ca. 20) may be sufficient to see quantum advantage already.
Impact of electron correlations on the k-resolved electronic structure of PdCrO2 revealed by Compton scattering
Authors: James A D N , Billington D , Dugdale S B
Published: May 2023

Delafossite PdCrO2 is an intriguing material which displays nearly-free electron and Mott insulating behaviour in different layers. Both angle-resolved photoemission spectroscopy (ARPES) and Compton scattering measurements have established a hexagonal Fermi surface in the material’s paramagnetic phase. However, the Compton experiment detected an additional structure in the projected occupancy which was originally interpreted as an additional Fermi surface feature not seen by ARPES. Here, we revisit this interpretation of the Compton data. State-of-the-art density functional theory (DFT) with dynamical mean field theory (DMFT), the so-called DFT+DMFT method, predicts the Mott insulating state along with a single hexagonal Fermi surface in excellent agreement with ARPES and Compton. However, DFT+DMFT fails to predict the intensity of the additional spectral weight feature observed in the Compton data. We infer that this discrepancy may arise from the DFT+DMFT not being able to correctly predict certain features in the shape and dispersion of the unoccupied quasiparticle band near the Fermi level. Therefore, a theoretical description beyond our DFT+DMFT model is needed to incorporate vital electron interactions, such as inter-layer electron coupling interactions which for PdCrO2 gives rise to the Kondo-like so-called intertwined excitation.
Mapping charge-transfer excitations in Bacteriochlorophyll dimers from first principles
Authors: Hashemi Zohreh , Knodt Matthias , Marques Mario R G , Leppert Linn
Published: May 2023

Photoinduced charge-transfer excitations are key to understand the primary processes of natural photosynthesis and for designing photovoltaic and photocatalytic devices. In this paper, we use Bacteriochlorophyll dimers extracted from the light harvesting apparatus and reaction center of a photosynthetic purple bacterium as model systems to study such excitations using first-principles numerical simulation methods. We distinguish four different regimes of intermolecular coupling, ranging from very weakly coupled to strongly coupled, and identify the factors that determine the energy and character of charge-transfer excitations in each case. We also construct an artificial dimer to systematically study the effects of intermolecular distance and orientation on charge-transfer excitations, as well as the impact of molecular vibrations on these excitations. Our results provide design rules for tailoring charge-transfer excitations in Bacteriochloropylls and related photoactive molecules, and highlight the importance of including charge-transfer excitations in accurate models of the excited-state structure and dynamics of Bacteriochlorophyll aggregates.
Effect of glycerin on mechanical properties of a hybrid kenaf-jute polyester composite
Authors: Maruthi Prashanth B H , Gouda P S Shivakumar , Manjunatha T S , Navaneeth I M , Chethan K M
Published: May 2023

Natural-based composites are gaining popularity among composite makers and end users because of their biocompatibility, low cost, and abundance. The influence of Glycerin as a plasticizer in various percentages ranging from 3% to 12% on Tensile, Flexural, Impact, Inter-laminar Shear Strength (ILSS), and Hardness characteristics of a Kenaf-Jute hybrid polyester composite, which is fabricated using hand layup followed by hot press method, was investigated in the present study. It was observed that a 6% Glycerin concentration in polyester Kenaf-Jute composite outperformed other composites in Tensile, Flexural, and Impact strengths in the range of 2 to 73%. This is evident by analyzing SEM images that better physical bonding between the Kenaf-Jute fibers with modified polyester resin using Glycerin. As the Glycerin content in the composite increases, the Hardness decreases when compared to without glycerin polyester.
Deep Learning for Epidemiologists: An Introduction to Neural Networks
Authors: Serghiou Stylianos , Rough Kathryn
Published: May 2023

Deep learning methods are increasingly being applied to problems in medicine and health care. However, few epidemiologists have received formal training in these methods. To bridge this gap, this article introduces the fundamentals of deep learning from an epidemiologic perspective. Specifically, this article reviews core concepts in machine learning (e.g., overfitting, regularization, and hyperparameters); explains several fundamental deep learning architectures (convolutional neural networks, recurrent neural networks); and summarizes training, evaluation, and deployment of models. Conceptual understanding of supervised learning algorithms is the focus of the article; instructions on the training of deep learning models and applications of deep learning to causal learning are out of this article’s scope. We aim to provide an accessible first step towards enabling the reader to read and assess research on the medical applications of deep learning and to familiarize readers with deep learning terminology and concepts to facilitate communication with computer scientists and machine learning engineers.
LPAD: using network construction and label propagation to detect topologically associating domains from Hi-C data
Authors: Liu Jian , Li Pingjing , Sun Jialiang , Guo Jun
Published: May 2023

With the development of chromosome conformation capture technique, the study of spatial conformation of a genome based on Hi-C technique has made a quantum leap. Previous studies reveal that genomes are folded into hierarchy of three-dimensional (3D) structures associated with topologically associating domains (TADs), and detecting TAD boundaries is of great significance in the chromosome-level analysis of 3D genome architecture. In this paper, we propose a novel TAD identification method, LPAD, which first extracts node correlations from global interactions of chromosomes based on the random walk with restart and then builds an undirected graph from Hi-C contact matrix. Next, LPAD designs a label propagation-based approach to discover communities and generates TADs. Experimental results verify the effectiveness and quality of TAD detections compared with existing methods. Furthermore, experimental evaluation of chromatin immunoprecipitation sequencing data shows that LPAD performs high enrichment of histone modifications remarkably nearby the TAD boundaries, and these results demonstrate LPAD’s advantages on TAD identification accuracy.
SLHSD: hybrid scaffolding method based on short and long reads
Authors: Luo Junwei , Guan Ting , Chen Guolin , Yu Zhonghua , Zhai Haixia , Yan Chaokun , Luo Huimin
Published: May 2023

In genome assembly, scaffolding can obtain more complete and continuous scaffolds. Current scaffolding methods usually adopt one type of read to construct a scaffold graph and then orient and order contigs. However, scaffolding with the strengths of two or more types of reads seems to be a better solution to some tricky problems. Combining the advantages of different types of data is significant for scaffolding. Here, a hybrid scaffolding method (SLHSD) is present that simultaneously leverages the precision of short reads and the length advantage of long reads. Building an optimal scaffold graph is an important foundation for getting scaffolds. SLHSD uses a new algorithm that combines long and short read alignment information to determine whether to add an edge and how to calculate the edge weight in a scaffold graph. In addition, SLHSD develops a strategy to ensure that edges with high confidence can be added to the graph with priority. Then, a linear programming model is used to detect and remove remaining false edges in the graph. We compared SLHSD with other scaffolding methods on five datasets. Experimental results show that SLHSD outperforms other methods. The open-source code of SLHSD is available at https://github.com/luojunwei/SLHSD.
Impact of house dust mite in vitiligo skin: environmental contribution to increased cutaneous immunity and melanocyte detachment
Authors: Bzioueche Hanene , Boniface Katia , Drullion Claire , Marchetti Sandrine , Chignon-Sicard Bérengère , Sormani Laura , Rocchi Stéphane , Seneschal Julien , Passeron Thierry , Tulic Meri K
Published: May 2023

Background

Vitiligo is an autoimmune skin disorder characterized by loss of melanocytes. Protease-mediated disruption of junctions between keratinocytes and/or keratinocyte intrinsic dysfunction may directly contribute to melanocyte loss. House dust mite (HDM), an environmental allergen with potent protease activity, contributes to respiratory and gut disease but also to atopic dermatitis and rosacea.

Objectives

To verify if HDM can contribute to melanocyte detachment in vitiligo and if so, by which mechanism(s).

Methods

Using primary human keratinocytes, human skin biopsies from healthy donors and patients with vitiligo, and 3D reconstructed human epidermis, we studied the effect of HDM on cutaneous immunity, tight and adherent junction expression and melanocyte detachment.

Results

HDM increased keratinocyte production of vitiligo-associated cytokines and chemokines and increased expression of toll-like receptor (TLR)-4. This was associated with increased in situ matrix-metalloproteinase (MMP)-9 activity, reduced cutaneous expression of adherent protein E-cadherin, increased soluble E-cadherin in culture supernatant and significantly increased number of suprabasal melanocytes in the skin. This effect was dose-dependent and driven by cysteine protease Der p1 and MMP-9. Selective MMP-9 inhibitor, Ab142180, restored E-cadherin expression and inhibited HDM-induced melanocyte detachment. Keratinocytes from patients with vitiligo were more sensitive to HDM-induced changes than healthy keratinocytes. All results were confirmed in a 3D model of healthy skin and in human skin biopsies.

Conclusions

Our results highlight that environmental mite may act as an external source of pathogen-associated molecular pattern molecules in vitiligo and topical MMP-9 inhibitors may be useful therapeutic targets. Whether HDM contributes to the onset of flares in vitiligo remains to be tested in carefully controlled trials.
Immune checkpoint inhibitor-induced bullous pemphigoid is characterized by interleukin (IL)-4 and IL-13 expression and responds to dupilumab treatment
Authors: Shipman William D , Singh Katelyn , Cohen Jeffrey M , Leventhal Jonathan , Damsky William , Tomayko Mary M
Published: May 2023

Immune checkpoint inhibitor-induced bullous pemphigoid (ICI-BP) is a clinically debilitating immune-related adverse event in need of novel therapeutic approaches, as conventional treatment can counteract intended tumour immunity. Here we demonstrate that interleukin (IL)-4 and IL-13 expression is elevated in ICI-BP similar to conventional autoimmune BP, and further demonstrate partial and complete disease clearance with dupilumab in four patients with ICI-BP. These data indicate that IL-4Rα inhibition may be a promising new therapy for ICI-BP.
A novel compound heterozygous variant in the LLS gene is associated with nonsyndromic hypotrichosis
Authors: Morice-Picard Fanny , Lanvin Pierre-Louis , Lasseaux Eulalie , Boralevi Franck , Léauté-Labrèze Christine  , Lebreton Louis
Published: May 2023

This report described a patient presenting with hypotrichosis simplex associated with compound heterozygosity for two novel LSS mutations. The clinical manifestations associated with mutations in the LSS gene, which is involved in sterol synthesis, are highly variable, ranging from simple hypotrichosis to alopecia with intellectual disability or cataracts. The identification of more patients and further functional studies are needed to improve the understanding of the pathophysiological mechanisms of LSS-related conditions.
Destined for the intestine: thymic selection of TCRαβ CD8αα intestinal intraepithelial lymphocytes
Authors: Joannou Kevin , Baldwin Troy A
Published: May 2023

The immune system is composed of a variety of different T-cell lineages distributed through both secondary lymphoid tissue and non-lymphoid tissue. The intestinal epithelium is a critical barrier surface that contains numerous intraepithelial lymphocytes that aid in maintaining homeostasis at that barrier. This review focuses on T-cell receptor αβ (TCRαβ) CD8αα intraepithelial lymphocytes, and how recent advances in the field clarify how this unique T-cell subset is selected, matures, and functions in the intestines. We consider how the available evidence reveals a story of ontogeny starting from agonist selection of T cells in the thymus and finishing through the specific signaling environment of the intestinal epithelium. We conclude with how this story raises further key questions about the development of different ontogenic waves of TCRαβ CD8αα IEL and their importance for intestinal epithelial homeostasis.
Interactive effects of temperature and bisphenol A on phytoplankton growth and community structure
Authors: Theus Meredith E , Michaels Julia , Fey Samuel B
Published: May 2023

Environmental contamination of bisphenol A (BPA) is a widespread and multifaceted issue with vast ecological, social and economic consequences. Thus, understanding how local environmental conditions, such as temperature, interact with BPA to affect populations and community dynamics remain important areas of research. Here, we conduct laboratory experiments aimed at understanding how environmental gradients of both temperature and BPA concentration influence freshwater phytoplankton population growth and community structure. We exposed phytoplankton assemblages comprised of three common species of green algae (Chlorella vulgaris, Ankistrodesmus braunii and Scenedesmus quadricauda) as well as isolates of each individual species to three BPA concentrations (0, 2, 13 mg/L BPA) and three temperatures (18, 23, 27°C) monitoring population growth and community structure (via biovolume). We observed antagonistic interactions between BPA and warmer temperatures, such that when warmer temperatures decreased growth (observed with A. braunii), high concentrations of BPA elevated growth at these warm temperatures; however, when warmer temperatures increased growth (C. vulgaris, S. quadricauda), high BPA concentrations diminished these gains. Although BPA exposure inhibited the growth of most C. vulgaris populations, growth was not reduced in A. braunii or S. quadricauda populations exposed to 2 mg/L BPA. Phytoplankton assemblage evenness (Pielou evenness index) decreased as BPA concentration increased and was consistently lowest under 27°C. Community composition was similar in assemblages cultured under 0 and 2 mg/L BPA under 18 and 23°C but was most similar between assemblages cultured under 2 and 13 mg/L BPA under 27°C. These results indicate that local environmental temperatures can mediate the consequences of BPA for freshwater phytoplankton growth rates and community structure and that BPA can diminish potential gains of increased growth rate for warm-adapted phytoplankton species at high environmental temperatures.
Friend or foe? Using eye-tracking technology to investigate the visual discrimination ability of giant pandas
Authors: Huang Xinrui , Li Guo , Zhang Guiquan , Li Zixiang , Zhao Lin , Zhu Mengdie , Xiang Qinghua , Liu Xuefeng , Tian Mei , Zhang Hemin , Buesching Christina D , Liu Dingzhen
Published: May 2023

The role that visual discriminative ability plays among giant pandas in social communication and individual discrimination has received less attention than olfactory and auditory modalities. Here, we used an eye-tracker technology to investigate pupil fixation patterns for 8 captive male giant pandas Ailuropoda melanoleuca. We paired images (N = 26) of conspecifics against: 1) sympatric predators (gray wolves and tigers), and non-threatening sympatric species (golden pheasant, golden snub-nosed monkey, takin, and red panda), 2) conspecifics with atypical fur coloration (albino and brown), and 3) zookeepers/non-zookeepers wearing either work uniform or plain clothing. For each session, we tracked the panda’s pupil movements and measured pupil first fixation point (FFP), fixation latency, total fixation count (TFC), and duration (TFD) of attention to each image. Overall, pandas exhibited similar attention (FFPs and TFCs) to images of predators and non-threatening sympatric species. Images of golden pheasant, snub-nosed monkey, and tiger received less attention (TFD) than images of conspecifics, whereas images of takin and red panda received more attention, suggesting a greater alertness to habitat or food competitors than to potential predators. Pandas’ TFCs were greater for images of black-white conspecifics than for albino or brown phenotypes, implying that familiar color elicited more interest. Pandas reacted differently to images of men versus women. For images of women only, pandas gave more attention (TFC) to familiar combinations (uniformed zookeepers and plain-clothed non-zookeepers), consistent with the familiarity hypothesis. That pandas can use visual perception to discriminate intra-specifically and inter-specifically, including details of human appearance, has applications for panda conservation and captive husbandry.
CineECG analysis provides new insights into Familial ST-segment Depression Syndrome
Authors: Frosted Rasmus , Paludan-Müller Christian , Vad Oliver Bundgaard , Olesen Morten Salling , Bundgaard Henning , van Dam Peter , Christensen Alex Hørby
Published: May 2023

Aims

Familial ST-segment Depression Syndrome (Fam-STD) is a novel inherited cardiac disease associated with arrhythmias and sudden cardiac death. This study aimed at investigating the cardiac activation pathway in patients with Fam-STD, modelling the electrocardiogram (ECG) phenotype, and performing in-depth ST-segment analyses.

Methods and results

CineECG analysis of patients with Fam-STD and age- and sex-matched controls. The groups were compared using the CineECG software which included the trans-cardiac ratio and the electrical activation pathway. We simulated the Fam-STD ECG phenotype by adjusting action potential duration (APD) and action potential amplitude (APA) in specific cardiac regions. High-resolution ST-segment analyses were performed per lead by dividing the ST-segment into nine 10 ms subintervals. Twenty-seven Fam-STD patients (74% females, mean age 51.6 ± 6.2 years) and 83 matched controls were included. Among Fam-STD patients, electrical activation pathway analysis in the anterior-basal orientation showed significantly abnormal direction toward the basal areas of the heart starting from QRS 60–89 ms until Tpeak-Tend (all P < 0.001). Simulations with shortened APD and reduced APA in the left ventricle basal regions recapitulated the Fam-STD ECG phenotype. Detailed ST-segment analyses showed significant differences in all nine 10 ms subintervals (all P < 0.01), with the most prominent findings during the 70–79/80–89 ms intervals.

Conclusion

CineECG analyses indicated abnormal repolarization with basal directions, and the Fam-STD ECG phenotype was simulated by reducing APD and APA in the left ventricle basal regions. Detailed ST-analysis showed amplitudes consistent with the proposed diagnostic criteria for Fam-STD patients. Our findings provide new insight into the electrophysiological abnormalities of Fam-STD.
Coverage by examinations associated with early detection of colorectal neoplasia in the Czech Republic
Authors: Ngo Ondřej , Hejcmanová Kateřina , Suchánek Štěpán , Pehalová Lucie , Dušek Ladislav , Zavoral Miroslav , Bureš Jan , Seifert Bohumil , Hejduk Karel , Král Norbert , Májek Ondřej
Published: May 2023

Background

Coverage by examinations is a crucial indicator of the future impact on the burden of colorectal cancer (CRC). The study aimed to evaluate coverage by examinations associated with CRC screening and early cancer detection of CRC in the Czech Republic. The burden of CRC was also assessed.

Methods

The novel nationwide administrative registry with individual data (period 2010–19) was used to evaluate coverage by examinations for screening faecal occult blood test and colonoscopy. In the second step, additional examinations for early CRC detection were included in the coverage calculation (complete coverage). Age-specific trends in CRC incidence (period 1977–2018) were investigated using Joinpoint regression.

Results

Coverage by screening examinations within recommended interval was around 30%. Complete coverage reached >37% and >50% at the 3-year interval. The coverage by examinations for the non-screening population aged 40–49 years was almost 4% and 5% (most of them were colonoscopies) at the 3-year interval. In age groups aged ≥50 years, we observed a significant annual decline, especially in the 50–69 age group, with recent annual decreases reaching up to 5–7%. The change in trend and the recent decline were also observed in the age group 40–49.

Conclusions

More than half of the target screening population was covered by examinations potentially associated with early detection and subsequent treatment of colorectal neoplasms. The substantial coverage by potentially prophylactic examinations might be an explanation for the considerable decrease in CRC incidence.