bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of a thin vertical porous barrier on the water wave scattering by a porous breakwater
Authors: Chanda Ayan , Pramanik Satyajit
Published: June 2023

Porous breakwaters are introduced to reduce the impact of wave load on various marine structures and dissipate unwanted wave energy by creating a tranquility zone. This type of marine structure can have practical implications for the development of artificial breeding or nursing grounds for fish and other sea animals. We theoretically investigated the water wave scattering by a surface-piercing porous breakwater in the presence of a thin vertical porous barrier in the framework of linear potential flow theory. Flow through the vertical porous barrier is considered using the model of Yu [“Diffraction of water waves by porous breakwaters,” J. Waterw., Port, Coastal, Ocean Eng. 121, 275–282 (1995)] under the assumption of fine pores. We use the eigenfunction expansion method to obtain solutions of the associated boundary value problems analytically. We develop semi-analytical solutions of the proposed mathematical problem using matching boundary conditions along boundaries of individual successive regions of the system. For wave scattering by a barrier-breakwater system with focus on wave energy dissipation, the effect of various wave and structural parameters on the reflection and transmission coefficients, dissipation coefficient, and wave force on the system are studied. The practical interest in this problem stems from the result that for the barrier-breakwater system, there exists a critical value of wave inclination angle below which wave reflection is minimum and wave energy dissipation is maximum. The results have implications for the proposed problem to harness energy from ocean waves and other problems related to the design and enhancement of the hydrodynamic performance of the breakwater in the marine environment.
The influence of cryogenic temperature on the shock structure of impinging under-expanded flow over a convex surface
Authors: Aslani Alireza
Published: June 2023

This study comprehensively investigates the effect of cryogenic nozzle inlet temperature on the flow structure and interactions of an under-expanded supersonic jet with a spherical solid surface. A combined experimental and numerical approach was employed to achieve this goal, utilizing high-speed Z-type schlieren visualization and Reynolds-averaged Navier–Stokes simulations with a Redlich–Kwong real gas equation of state. This study is significant as it addresses a relatively unexplored area of research on the flow structure of the cryogenic under-expanded supersonic jet. The study examines the shock pattern and interaction region through varying static inlet temperature (Tin = 178–290 K) and nozzle pressure ratio (NPR 5–14). Additionally, parameters including nozzle exit-to-throat area ratio (A/A* = 1.277), the distance between the sphere and the nozzle (1.5 cm), and the diameter of the sphere (d = 1.5 cm) were considered fixed. The results show that the supersonic jet exhibits a change in shock patterns in the first shock cell concerning the location and width of the Mach disk, accompanied by a shift in the location of the last shock crossing point and the shock plate. The simulation provides a more detailed insight into the flow, indicating a temperature drop to 105 K in the case of the cryogenic nozzle inlet. At such a low temperature, the compressibility factor exhibits a 5% reduction from unity, while in the case of the ambient nozzle inlet, the minimum temperature at the nozzle exit reached 170 K, leading to only a 1% drop in the compressibility factor, which is negligible. It triggers different flow structures concerning the nozzle inlet temperature. These findings can contribute to the complex flow structures of supersonic jets seen in different industrial and scientific fields.
Extremely large magnetoresistance in an unfilled skutterudite quadratic contact point semimetal CoP3
Authors: Fan Chenxin , Yuan Jian , Shi Xianbiao , Yang Yichen , Xi Chuanying , Pi Li , Wang Xia , Yu Na , Zou Zhiqiang , Wang Baotian , Shen Dawei , Guo Yanfeng
Published: June 2023

Extremely large magnetoresistance (EXMR) and high mobility are always desired for use in spintronic devices. Herein, we report the observation of EXMR and very large hole mobility reaching ∼ 2 × 104% (30 T) and ∼2 × 104 cm2 V−1 s−1, respectively, at 2 K in an unfilled skutterudite CoP3 crystal. The magnetotransport measurements unveil remarkable Shubnikov–de Haas quantum oscillations hosting nontrivial Berry phase induced by strong Zeeman splitting. First-principles calculations suggest band inversion between Co-dxy/yz and P-pz orbitals, which forms fourfold quadratic contact point at the Γ point above the Fermi level of ∼0.146 eV. The angle-resolved photoelectron spectroscopy measurements verify the calculated surface state. The results provide a quadratic contact point semimetal, which has potential applications in topological devices.
Emission of spacetime waves from the partial collapse of a compact object
Authors: Avila-Vargas Emmanuel , Moreno Claudia , Hernández-Jiménez Rafael
Published: June 2023

In this work, we describe the partial collapse of a compact object and the emission of spacetime waves as a result of back-reaction effects. As a source mass term, we propose a non-smooth continuous function that describes a mass-loss, and we then obtain the solution of such setting. We present three distinct examples of the evolution of the norm |Rnl(t, r*)| in terms of t, and four different results are shown for the parameter l = 1, 2, 5, 10; here, r* is the fixed radius of an observer outside the compact object. In all cases, the decay behavior is actually present at t ≫ 1 and becomes more evident for larger l. In addition, for the results that have smaller l’s, their amplitudes are larger when the asymptotic character of |Rnl(t, r*)| clearly appears. Finally, the farther away an observer is set, the fewer oscillations are perceived; however, from our particular fixed set of parameters, the best spot to observe the wiggles of the emitted spacetime waves is close to r* ≃ α.
Flow structure and dynamics behind cylinder arrays at Reynolds number ∼100
Authors: Sharifi Ghazijahani M. , Cierpka C.
Published: June 2023

The flow behind nine different arrays of cylinders is experimentally investigated via Particle Image Velocimetry (PIV) at a Reynolds number of Re ∼100 based on the diameter of the cylinders. Each array consists of a column of four cylinders in front and three in the rear. The horizontal distance between the two columns and the vertical distance between the cylinders within each column are varied for H/D=[2,4,8] and V/D=[2,4,6], resulting in nine different arrays denoted as mVnH, where m corresponds to V/D and n stands for H/D. The PIV measurements are conducted for 15 s at 200 Hz frequency, corresponding to 39 to 360 vortex shedding events for the wakes in this study. Then, proper orthogonal decomposition is applied to the velocity fields to analyze the flow dynamics. All arrays show unsteady flow, and based on their flow structures, they are classified in to three main categories of single bluff body (SBB), transitional (TR), and co-shedding (CS) flow. SBB characteristics can be seen for 2V2H and 2V4H arrays, but the latter has more steady vortex shedding as the H/D increases from 2 to 4. Then, 2V8H and 4V2H have an asymmetric flow with several vortex streets and act as an intermediary stage in the shift from SBB to CS flow structure when the distances are increased. The highest total kinetic energy values and widest probability density functions of the velocity components are observed for this group. The five remaining arrays in the CS group have symmetric flow, with three or five vortex streets present behind. However, based on the distances, the frequency and phase synchronization of the vortex streets change considerably, which might have an important effect on, for example, the heat transfer or the structural load of the cylinders.
Shock response of unidirectional carbon polymer composite up to pressures of 200 GPa
Authors: Mochalova Valentina , Utkin Alexander , Nikolaev Dmitry
Published: June 2023

Carbon fiber reinforced composite materials are often used to protect spacecraft from hypervelocity impacts with micrometeoroids or space debris. Therefore, shock-wave properties of these materials at pressures corresponding to orbital impact velocities are of interest. Experimental studies of shock compressibility of unidirectional carbon fiber polymer composite with longitudinal and transverse fiber orientation relative to the direction of shock-wave propagation have been carried out in the pressure range of up to 200 GPa. Particle velocity profiles on the composite surface-water window interface were recorded with a multichannel laser interferometer. The formation of a two-wave structure with a precursor amplitude from 1.5 to 3 GPa was observed with longitudinally oriented fibers. We show that Hugoniot of the composite material almost does not depend on the orientation of the carbon fibers, except for low pressures, when the particle velocity does not exceed 1 km/s. The graphite/diamond phase transition and the destruction of epoxy resin result in a characteristic kink on the Hugoniot curve with a distinct two-phase state region in the 23–35 GPa pressure range.
An OpenFOAM framework to model thermal bubble-driven micro-pumps
Authors: Hayes B. , Whiting G. L. , MacCurdy R.
Published: June 2023

Thermal bubble-driven micro-pumps (also known as inertial pumps) are an upcoming micro-pump technology that can be integrated directly into micro/mesofluidic channels to displace fluid without moving parts. These micro-pumps are high-power resistors that locally vaporize a thin layer of fluid above the resistor surface to form a high-pressure vapor bubble which performs mechanical work. Despite their geometric simplicity, thermal bubble-driven micro-pumps are complex to model due to the multiphysics couplings of Joule heating, thermal bubble nucleation, phase change, and multiphase flow. As such, most simulation approaches simplify the physics by neglecting Joule heating, nucleation, and phase change effects as done in this study. To date, there are no readily available, reduced physics open-source modeling tools that can resolve both pre-collapse (defined as when the bubble is expanding and collapsing) and post-collapse (defined as when the bubble has re-dissolved back into the subcooled fluid) bubble and flow dynamics. In this study, an OpenFOAM framework for modeling thermal bubble-driven micro-pumps is presented, validated, and applied. The developed OpenFOAM model agrees with both experimental data and commercial computational fluid dynamics (CFD) software, FLOW-3D. Additionally, we assess the shape of the transient velocity profile during a pump cycle for the first time and find that it varies substantially from theoretical Poiseuille flow during pre-collapse but is within 25% of the theoretical flow profile during post-collapse. We find that this deviation is due to flow never becoming fully developed during each pump cycle. We envision the developed OpenFOAM framework as an open-source CFD toolkit for microfluidic designers to simulate devices with thermal bubble-driven micro-pumps.
A quantitative assessment of deformation energy in intermolecular interactions: How important is it?
Authors: Sargent Caroline T. , Kasera Raina , Glick Zachary L. , Sherrill C. David , Cheney Daniel L.
Published: June 2023

Dimer interaction energies have been well studied in computational chemistry, but they can offer an incomplete understanding of molecular binding depending on the system. In the current study, we present a dataset of focal-point coupled-cluster interaction and deformation energies (summing to binding energies, De) of 28 organic molecular dimers. We use these highly accurate energies to evaluate ten density functional approximations for their accuracy. The best performing method (with a double-ζ basis set), B97M-D3BJ, is then used to calculate the binding energies of 104 organic dimers, and we analyze the influence of the nature and strength of interaction on deformation energies. Deformation energies can be as large as 50% of the dimer interaction energy, especially when hydrogen bonding is present. In most cases, two or more hydrogen bonds present in a dimer correspond to an interaction energy of −10 to −25 kcal mol−1, allowing a deformation energy above 1 kcal mol−1 (and up to 9.5 kcal mol−1). A lack of hydrogen bonding usually restricts the deformation energy to below 1 kcal mol−1 due to the weaker interaction energy.
A novel three-dimensional analytical tornado model constructed based on force balance analysis
Authors: Khoo Boo Cheong
Published: June 2023

The analytical model for tornado vortices is crucial in both the wind field characterization and the tornado-resistant design of civil structures. The objective of this study is to derive a novel three-dimensional analytical tornado model from the vortex governing equations simplified based on the force balance analysis in tornado-like vortices (TLVs). First, TLVs with different swirl ratios are generated in a numerical simulator utilizing the large-eddy simulation. Then, the forces in the axisymmetric vortex governing equations are calculated for time-averaged TLVs. The governing equations in the single-cell TLV are simplified by ignoring some significantly small terms. Finally, a novel three-dimensional analytical tornado model, which contains the radial, tangential, and vertical velocity as well as the pressure, has been proposed and validated. The result shows that the force balance in the single-cell TLV is simpler than that in TLVs with larger swirl ratios. In the single-cell TLV, the viscous forces in the radial and vertical directions can be neglected, while the tangential viscous force remains to play an important role in the force balance. The proposed model mitigates the limitations of existing models in describing single-cell tornado vortices, such as only two-dimensional velocity being given, the neglection of the vertical shear effects near the ground, and the infinite velocity at high altitudes. It shows good agreement with the numerical and experimental TLVs as well as the real tornado.
A data-driven framework for learning hybrid dynamical systems
Authors: Li Yang , Xu Shengyuan , Duan Jinqiao , Huang Yong , Liu Xianbin
Published: June 2023

The existing data-driven identification methods for hybrid dynamical systems such as sparse optimization are usually limited to parameter identification for coefficients of pre-defined candidate functions or composition of prescribed function forms, which depend on the prior knowledge of the dynamical models. In this work, we propose a novel data-driven framework to discover the hybrid dynamical systems from time series data, without any prior knowledge required of the systems. More specifically, we devise a dual-loop algorithm to peel off the data subject to each subsystem of the hybrid dynamical system. Then, we approximate the subsystems by iteratively training several residual networks and estimate the transition rules by training a fully connected neural network. Several prototypical examples are presented to demonstrate the effectiveness and accuracy of our method for hybrid models with various dimensions and structures. This method appears to be an effective tool for learning the evolutionary governing laws of hybrid dynamical systems from available data sets with wide applications.
A magnetic-field-driven neuristor for spiking neural networks
Authors: Mou Hongming , Luo Zhaochu , Zhang Xiaozhong
Published: June 2023

Artificial intelligence has been widely deployed in many fields with remarkable success. Among various artificial neural network structures in artificial intelligence, the spiking neural network, as the next-generation artificial neural network, closely mimics the natural neural networks. It contains the all-or-nothing and diverse periodic spiking, which is an analogy to the behavior of natural neurons. Artificial devices that perform the function of neurons are called neuristors. Most existing neuristors are driven by electrical signals, which suffer the problem of impedance mismatch between input and output neuristors. By exploiting the S-shape negative differential resistances element that is sensitive to the external magnetic field, we constructed a magnetic-field-driven neuristor. Magnetic fields can stimulate all-or nothing spiking, and its shape and frequency can be modulated through capacitances in the circuit. As magnetic fields serve as the information carrier, the cascading of our neuristors can get rid of the electrical impedance mismatch, promising a scalable hardware platform for spiking neural networks.
A novel bearing diagnosis method under random impact disturbance based on the nonlinear convolutional sparse filtering
Authors: Yao Shunxiang , Zhang Zongzhen , Han Baokun , Bao Huaiqian , Wang Jinrui , Zheng Jiansong
Published: June 2023

The fault diagnostic approach based on sparse optimization has been receiving considerable attention. Which shows superior robustness and noise adaptability. However, in the real working environment, the collected bearing signals are often accompanied by random impact interference owing to alterations in working circumstances and load mutations. In this paper, the nonlinear sparse metric is used to reduce the interference of random shock excitation (FNCSF). The nonlinear activation has different activation coefficients for different amplitudes, which can change the sparsity distribution of the raw data. Firstly, the influence of different nonlinear activation functions on the diagnostic performance is studied. Then, in order to solve the scale inconsistency caused by nonlinear activation, the nonlinear function is created to the generalized form to further improve the noise adaptability of feature extraction. The second-order Gaussian fitting is used to improve the performance of the learning filter. Simulation and experimental results verify the performance of the proposed method. The results demonstrate that the suggested technique can significantly reduce the interference of random impact components.
Measuring defects in high-speed production lines—a three-phase convolutional neural network model
Authors: Wang Kung-Jeng , Lee Ya-Xuan
Published: June 2023

Conventional automatic optical inspection (AOI) systems using rule-based image processing suffer from precision and velocity issues, particularly when simultaneously measuring multiple defects of a product in a high-speed production line. Such AOI stations usually become a bottleneck in the line. This paper presents a three-phase model for defect detection based on convolutional neural network to release the cycle time of the line. The phase I model using a deep residual network (ResNet50) performs defect classification of products with high accuracy. The phase II model is another independent ResNet50 that classifies defect products into defect categories, rescuing good products that have been mistakenly killed in the previous stage and replacing the conventional re-inspection labors. The phase III model is a you only look once—based network that detects multiple defects and their positions simultaneously in a single product, providing informative quality data for continuous improvement. The proposed model successfully resolves the issue of multiple-defect and multiple-len quality inspection in a high-speed production line. The proposed model resolved defect inspection by integrating object detection and defect classification simultaneously. By deploying the three-phase model in a tiny electronic connector component production line, the present model has demonstrated that it reaches high precision and facilitates prompt quality correction for high-speed production lines.
Modeling ultra-high dose rate electron and proton FLASH effect with the physicochemical approach
Authors: Tan Hai Siong , Teo Kevin Boon Keng , Dong Lei , Friberg Andrew , Koumenis Constantinos , Diffenderfer Eric , Zou Jennifer Wei
Published: June 2023

Objective. A physicochemical model built on the radiochemical kinetic theory was recently proposed in (Labarbe et al
2020) to explain the FLASH effect. We performed extensive simulations to scrutinize its applicability for oxygen depletion studies and FLASH-related experiments involving both proton and electron beams. Approach. Using the dose and beam delivery parameters for each FLASH experiment, we numerically solved the radiochemical rate equations comprised of a set of coupled nonlinear ordinary differential equations to obtain the area under the curve (AUC) of radical concentrations. Main results. The modeled differences in AUC induced by ultra-high dose rates appeared to correlate well with the FLASH effect. (i) For the whole brain irradiation of mice performed in (Montay-Gruel et al
2017), the threshold dose rate values for memory preservation coincided with those at which AUC started to decrease much less rapidly. (ii) For the proton pencil beam scanning FLASH of (Cunningham et al
2021), we found linear correlations between radicals’ AUC and the biological endpoints: TGF-β1, leg contracture and plasma level of cytokine IL-6. (iii) Compatible with the findings of the proton FLASH experiment in (Kim et al
2021), we found that radicals’ AUC at the entrance and mid-Spread-Out Bragg peak regions were highly similar. In addition, our model also predicted ratios of oxygen depletion G-values between normal and UHDR irradiation similar to those observed in (Cao et al
2021) and (El Khatib et al
2022). Significance. Collectively, our results suggest that the normal tissue sparing conferred by UHDR irradiation may be due to the lower degree of exposure to peroxyl and superoxide radicals. We also found that the differential effect of dose rate on the radicals’ AUC was less pronounced at lower initial oxygen levels, a trait that appears to align with the FLASH differential effect on normal versus tumor tissues.
A novel three-phase excitation piezoelectric motor for macro-micro actuation: integration design, systematic modeling, and experimental evaluation
Authors: Qiu Jianmin , Yang Ying , Jin Jiamei , Wang Liang , Wang Yiping , Zhang Jiyang
Published: June 2023

Macro-micro actuators require complex feedback control systems to obtain high positioning cooperativeness. However, the mechanical connections of macro-micro actuators are generally redundant in terms of their size, which is highly unfavorable for both miniaturization and integration. This paper presents an approach to address this problem based on a novel integration design for a three-phase excitation piezoelectric motor (TPM) that is capable of performing macro-micro actuation by switching its operating mode from resonant to nonresonant. The load capacity of the proposed TPM can reach 0.39 Nm with a maximum speed of 3.82 rad s−1 (36.5 rpm). This performance is achieved by using a unique triangular flexible stator that contains three piezoelectric stack actuators acting as vibrators and is excited by a three-phase electrical signal. A time-domain electromechanical coupling dynamic model is developed to determine the dynamic behavior of the proposed motor, and the modeling results are validated successfully by experimental results obtained from a fabricated prototype. The proposed motor is expected to be helpful for integration design of piezoelectric devices that require macro-micro actuation.
Effect of training on the cyclic behaviour of SMA wire
Authors: Davarnia Danial , Cheng Shaohong , Engelen Niel Van
Published: June 2023

Shape memory alloys (SMAs) are a new generation of smart metallic materials with numerous unique and widely applicable characteristics. With their superelasticity and ability to dissipate energy under cyclic loading, SMAs are an excellent choice for passive vibration energy dissipation systems. However, due to functional fatigue, the energy dissipation and re-centring capacity of virgin SMA dwindles at a decreasing rate during cyclic loading and eventually reaches a stable level. Since for vibration control applications stable mechanical properties with predictable responses to vibrational forces are preferred, preloading SMA wires for mechanical training is proposed to overcome this drawback. Nevertheless, the effect of training conditions on the mechanical behaviour of SMA wires has only been investigated in a few studies. To fill this research gap, the influence of different training parameters, such as strain amplitude, frequency, number of cycles and prestrain, on the mechanical behaviour of SMA wires is examined. The results show that while a sufficient number of cycles and certain level of strain amplitude are required to reach a stable stress–strain relation, training frequency is the most important parameter for eliminating residual strain.
Bending characteristics of stacked REBCO cable under different stacking modes
Authors: Yuan Songzhen , Ma Tao , Dai Shaotao , Song Meng , Li Li
Published: June 2023

High-temperature superconducting tapes provide new materials for various high-current applications. The stacked tape cable (STC) is one of the promissing structure, which is based on the idea to stack single REBCO tapes. However, stacking the tapes increases the thickness of the cable and reduces its bending performance. In order to study the bending behavior of stacked tapes, bending tests of single tape was first made to analyze the strain of the REBCO layer at different bending radii, and the strain-current curves were obtained by empirical equations. The cables were stacked in both back-to-back and face-to-face modes. The strains of the REBCO layers in the tapes are calculated, and the critical currents of the cables are experimentally measured at various bending radii. The bending characteristics of the cable are analyzed using the fitted equation, and the experimental results demonstrate good agreement with the calculated results. The results indicate that the REBCO layer exhibits improved bending performance under compression, and thinner cables perform better. Therefore, we added copper tape to adjust the position of the neutral axis to optimize the bending performance. The results show that this method can effectively reduce the bending radius of the stacked cable.
Fiber grating sensors and their recent applications in biomedical domain
Authors: B S Kavitha , Pant Shweta , Sood A K , Asokan S
Published: June 2023

Sensors play an important role in measuring various physio-chemical and biological parameters. Biomedical applications of sensors include early level diagnosis of diseases, treatment technique enhancement and also monitoring the effect of medical techniques using suitable biomedical devices. The sensors which are deemed suitable for biomedical applications need to be fast, accurate, flexible, small, and most importantly, biocompatible. The inherent advantages of fibre optic sensors, such as small foot print, electrical passiveness, multiplexing capability and fast response make them the most preferred for biomedical sensing applications. Fibre optics sensors are generally used in the measurement of parameters such as temperature, strain, pressure, displacement, angle, and force. And find applications in diverse regimes like structural health monitoring, shape sensing, seismic sensing; in the bio medical domain, they have been deployed in gait analysis, pulse rate monitoring, body joint angle measurements, acquisition of respiratory parameters, cardiovascular parameters and many more. Despite being a topic of significant interest in biomedical applications, the adoptablility of optical sensors in clinical practice is not very encouraging. Hence, there is a need to address the reasons for the same, and the present review aims to highlight some critical areas. The present review paper primarily discusses the optical fibre grating techniques: their fabrication methods, the applications of these sensors in biophysical and biomechanical measurements, bio proteins and biomarker detection in body fluids. The review also discusses the bottlenecks in the clinical application of these sensors. The comparison of the performance of the optical fibre sensors with other sensing techniques is also discussed in this review paper.
Does Frequency of Baseline Testing Influence Concussion Diagnostic Decision Making Among College Athletes
Authors: Crane Andrew , Roccaforte Analise , Webbe Frank , LoGalbo Anthony
Published: June 2023

Objective

Concussion is a growing public health concern given the large number of youth and collegiate athletes participating in collision sports. Sport-related concussions can have an adverse impact on student-athletes’ health and academic performance. Athletic programs within academic organizations are motivated to employ the most effective and efficient diagnostic and recovery procedures to minimize the duration and impact of these symptoms on student-athletes’ functioning. The present study sought to further our understanding regarding the value and frequency of conducting baseline assessments when evaluating sport-related concussions.

Method

A total of 41 athletes (24 men, 17 women) between the ages of 18 and 22 were evaluated following suspected concussive injury between 2015 and 2018. Post-injury test results were compared to baselines that had been collected either 1 or 2 years prior, and to normative data, to determine consistency in diagnostic outcomes.

Results

Baseline test/retest reliability using Pearson’s bivariate correlations revealed modest correlations on measures of verbal and visual memory (0.437–0.569) and very strong correlations on measures of reaction time and visual-motor speed (0.811–0.821). Meanwhile, minimal if any differences in clinical decision-making regarding the diagnostic outcome was observed when comparing post-injury test results to different baselines and to normative data.

Conclusions

Findings indicate that yearly baseline testing may not improve diagnostic accuracy, and in many cases, normative data may be adequate for decision-making. Additional research should evaluate the potential benefit of baseline testing in return-to-play decision-making among broader athletic populations.
S-leaping: an efficient downsampling method for large high-throughput sequencing data
Authors: Kuwahara Hiroyuki , Gao Xin
Published: June 2023

Motivation

Sequencing coverage is among key determinants considered in the design of omics studies. To help estimate cost-effective sequencing coverage for specific downstream analysis, downsampling, a technique to sample subsets of reads with a specific size, is routinely used. However, as the size of sequencing becomes larger and larger, downsampling becomes computationally challenging.

Results

Here, we developed an approximate downsampling method called s-leaping that was designed to efficiently and accurately process large-size data. We compared the performance of s-leaping with state-of-the-art downsampling methods in a range of practical omics-study downsampling settings and found s-leaping to be up to 39% faster than the second-fastest method, with comparable accuracy to the exact downsampling methods. To apply s-leaping on FASTQ data, we developed a light-weight tool called fadso in C. Using whole-genome sequencing data with 208 million reads, we compared fadso’s performance with that of a commonly used FASTQ tool with the same downsampling feature and found fadso to be up to 12% faster with 21% lower memory usage, suggesting fadso to have up to 40% higher throughput in a parallel computing setting.

Availability and implementation

The C source code for s-leaping, as well as the fadso package is freely available at https://github.com/hkuwahara/sleaping.
ESPERANTO: a GLP-field sEmi-SuPERvised toxicogenomics metadAta curatioN TOol
Authors: Di Lieto Emanuele , Serra Angela , Inkala Simo Iisakki , Saarimäki Laura Aliisa , del Giudice Giusy , Fratello Michele , Hautanen Veera , Annala Maria , Federico Antonio , Greco Dario
Published: June 2023

Biological data repositories are an invaluable source of publicly available research evidence. Unfortunately, the lack of convergence of the scientific community on a common metadata annotation strategy has resulted in large amounts of data with low FAIRness (Findable, Accessible, Interoperable and Reusable). The possibility of generating high-quality insights from their integration relies on data curation, which is typically an error-prone process while also being expensive in terms of time and human labour. Here, we present ESPERANTO, an innovative framework that enables a standardized semi-supervised harmonization and integration of toxicogenomics metadata and increases their FAIRness in a Good Laboratory Practice-compliant fashion. The harmonization across metadata is guaranteed with the definition of an ad hoc vocabulary. The tool interface is designed to support the user in metadata harmonization in a user-friendly manner, regardless of the background and the type of expertise.

Availability and implementation

ESPERANTO and its user manual are freely available for academic purposes at https://github.com/fhaive/esperanto. The input and the results showcased in Supplementary File S1 are available at the same link.
Placing joint hypermobility in context: traits, disorders and syndromes
Authors: Morlino Silvia , Castori Marco
Published: June 2023

Background

Joint hypermobility (JHM) is a common physical trait. It may occur alone or in combination with musculoskeletal (MSK) pain, outside or within more complex phenotypes. Hypermobility spectrum disorders (HSD) are diagnosed in individuals with JHM and related MSK pain, when an alternative diagnosis cannot be identified. Conversely, the Ehlers-Danlos syndrome (EDS) encompasses a group of rare hereditary connective tissue disorders featuring JHM along with other pleiotropic manifestations. The 2017 EDS Classification identifies 13 different subtypes. Hypermobile EDS (HEDS) is the only EDS variant still lacking a confirmatory test.

Sources of data

Literature was reviewed searching for the most relevant papers related to key arguments. Particular attention was focused on papers published after the 2017 Classification.

Areas of agreement

Definition, epidemiology, assessment tools and patterns of JHM are presented. The morbid nature of the 2017 EDS Classification and of the ‘spectrum’ is also illustrated.

Areas of controversy

We discuss current limitations and disagreements concerning the ‘spectrum’, HSD and HEDS.

Growing points

In the clinical context, elucidation of the pathophysiology of pain related to JHM should develop in parallel with the analysis of pleiotropic manifestations of syndromes with JHM.

Areas timely for developing research

Future challenges concerning classification, nosology, diagnosis and management of JHM, EDS and related disorders are discussed.
Beta resting-state functional connectivity predicts tactile spatial acuity
Authors: Sasaki Ryoki , Kojima Sho , Otsuru Naofumi , Yokota Hirotake , Saito Kei , Shirozu Hiroshi , Onishi Hideaki
Published: June 2023

Tactile perception is a complex phenomenon that is processed by multiple cortical regions via the primary somatosensory cortex (S1). Although somatosensory gating in the S1 using paired-pulse stimulation can predict tactile performance, the functional relevance of cortico-cortical connections to tactile perception remains unclear. We investigated the mechanisms by which corticocortical and local networks predict tactile spatial acuity in 42 adults using magnetoencephalography (MEG). Resting-state MEG was recorded with the eyes open, whereas evoked responses were assessed using single- and paired-pulse electrical stimulation. Source data were used to estimate the S1-seed resting-state functional connectivity (rs-FC) in the whole brain and the evoked response in the S1. Two-point discrimination threshold was assessed using a custom-made device. The beta rs-FC revealed a negative correlation between the discrimination threshold and S1–superior parietal lobule, S1–inferior parietal lobule, and S1–superior temporal gyrus connection (all P < 0.049); strong connectivity was associated with better performance. Somatosensory gating of N20m was also negatively correlated with the discrimination threshold (P = 0.015), with weak gating associated with better performance. This is the first study to demonstrate that specific beta corticocortical networks functionally support tactile spatial acuity as well as the local inhibitory network.
Efficacy and Safety of Moxidectin-Albendazole and Ivermectin-Albendazole Combination Therapy Compared to Albendazole Monotherapy in Adolescents and Adults Infected with Trichuris trichiura: A Randomized, Controlled Superiority Trial
Authors: Sprecher Viviane P , Coulibaly Jean T , Hürlimann Eveline , Hattendorf Jan , Keiser Jennifer
Published: June 2023

Background

The currently recommended benzimidazole monotherapy is insufficiently effective to control infection with the soil-transmitted helminth Trichuris trichiura. Ivermectin-albendazole combination has shown promising, but setting-dependent efficacy, with therapeutic underperformance in Côte d’Ivoire. We evaluated whether moxidectin-albendazole could serve as an alternative to albendazole monotherapy in Côte d’Ivoire.

Methods

In this community-based, randomized, placebo-controlled, parallel-group superiority trial, individuals aged 12–60 years were screened for T. trichiura eggs in their stool using quadruplicate Kato-Katz thick smears. Diagnostically and clinically eligible participants were randomly assigned (1:1:1) to receive single oral doses of moxidectin (8 mg) and albendazole (400 mg), ivermectin (200 µg/kg) and albendazole (400 mg), or albendazole (400 mg) and placebo. The primary outcome was proportion cured, ie, cure rate (CR), assessed at 2–3 weeks post-treatment. Safety endpoints were assessed pre-treatment and at 3 and 24 hours post-treatment.

Results

For the 210 participants with primary outcome data, we observed CRs of 15.3% in the moxidectin-albendazole arm and 22.5% in the ivermectin-albendazole arm, which did not differ significantly from the CR of 13.4% in the albendazole arm (differences: 1.8%-points [95% confidence interval: −10.1 to 13.6] and 9.1%-points [−3.9 to 21.8], respectively). Most common adverse events were abdominal pain (range across arms: 11.9%–20.9%), headache (4.7%–14.3%), and itching (5.8%–13.1%), which were predominantly mild and transient.

Conclusions

All therapies showed similar low efficacy in treating trichuriasis in Côte d’Ivoire. Alternative treatment options need to be evaluated, and further analyses should be conducted to understand the lack of enhanced activity of the combination therapies in Côte d’Ivoire.

Clinical Trials Registration

NCT04726969.
Ascending thoracic aortic aneurysm elongation occurs in parallel with dilatation in a nonsurgical population
Authors: Gulati Arushi , Zamirpour Siavash , Leach Joseph , Khan Amir , Wang Zhongjie , Xuan Yue , Hope Michael D , Saloner David A , Guccione Julius M , Ge Liang , Tseng Elaine E
Published: June 2023

OBJECTIVES

Rapid diameter growth is a criterion for ascending thoracic aortic aneurysm repair; however, there are sparse data on aneurysm elongation rate. The purpose of this study was to assess aortic elongation rates in nonsyndromic, nonsurgical aneurysms to understand length dynamics and correlate with aortic diameter over time.

METHODS

Patients with <5.5-cm aneurysms and computed tomography angiography imaging at baseline and 3–5 years follow-up underwent patient-specific three-dimensional aneurysm reconstruction using MeVisLab. Aortic length was measured along the vessel centreline between the annulus and aortic arch. Maximum aneurysm diameter was determined from imaging in a plane normal to the vessel centreline. Average rates of aneurysm growth were evaluated using the longest available follow-up.

RESULTS

Over the follow-up period, the mean aortic length for 67 identified patients increased from 118.2 (95% confidence interval: 115.4–121.1) mm to 120.2 (117.3–123.0) mm (P = 0.02) and 15 patients (22%) experienced a change in length of ≥5% from baseline. The mean annual growth rate for length [0.38 (95% confidence interval: 0.11–0.65) mm/year] was correlated with annual growth rate for diameter [0.1 (0.03–0.2) mm/year] (rho = 0.30, P = 0.01). Additionally, annual percentage change in length [0.3 (0.1–0.5)%/year] was similar to percentage change in diameter [0.2 (0.007–0.4)%/year, P = 0.95].

CONCLUSIONS

Aortic length increases in parallel with aortic diameter at a similar percentage rate. Further work is needed to identify whether elongation rate is associated with dissection risk. Such studies may provide insight into why patients with aortic diameters smaller than surgical guidelines continue to experience dissection events.
Use, misuse, and pitfalls of the drug challenge test in the diagnosis of the Brugada syndrome
Authors: Wilde Arthur A M , Amin Ahmad S , Morita Hiroshi , Tadros Rafik
Published: June 2023

The diagnosis of Brugada syndrome (BrS) requires the presence of a coved (Type 1) ST segment elevation in the right precordial leads of the electrocardiogram (ECG). The dynamic nature of the ECG is well known, and in patients with suspected BrS but non-diagnostic ECG at baseline, a sodium channel blocker test (SCBT) is routinely used to unmask BrS. There is little doubt, however, that in asymptomatic patients, a drug-induced Brugada pattern is associated with a much better prognosis compared to a spontaneous Type 1 ECG. The SCBT is also increasingly used to delineate the arrhythmogenic substrate during ablation studies. In the absence of a “gold standard” for the diagnosis of BrS, sensitivity and specificity of the SCBT remain elusive. By studying patient groups with different underlying diseases, it has become clear that the specificity of the test may not be optimal. This review aims to discuss the pitfalls of the SCBT and provides some directions in whom and when to perform the test. It is concluded that because of the debated specificity and the overall very low risk for future events in asymptomatic individuals, patients should be properly selected and counseled before SCBT is performed and that SCBT should not be performed in asymptomatic patients with a Type 2 Brugada pattern and no family history of BrS or sudden death.
Merging virtual and physical experiences: extended realities in cardiovascular medicine
Authors: Tsai Tsung-Ying , Onuma Yoshinobu , Złahoda-Huzior Adriana , Kageyama Shigetaka , Dudek Dariusz , Wang Qingdi , Lim Ruth P , Garg Scot , Poon Eric K W , Puskas John , Ramponi Fabio , Jung Christian , Sharif Faisal , Khokhar Arif A , Serruys Patrick W
Published: June 2023

Technological advancement and the COVID-19 pandemic have brought virtual learning and working into our daily lives. Extended realities (XR), an umbrella term for all the immersive technologies that merge virtual and physical experiences, will undoubtedly be an indispensable part of future clinical practice. The intuitive and three-dimensional nature of XR has great potential to benefit healthcare providers and empower patients and physicians. In the past decade, the implementation of XR into cardiovascular medicine has flourished such that it is now integrated into medical training, patient education, pre-procedural planning, intra-procedural visualization, and post-procedural care. This review article discussed how XR could provide innovative care and complement traditional practice, as well as addressing its limitations and considering its future perspectives.
Personalised antiplatelet therapies for coronary artery disease: what the future holds
Authors: Capodanno Davide , Angiolillo Dominick J
Published: June 2023

Coronary artery disease (CAD) is one of the leading causes of death globally, and antiplatelet therapy is crucial for both its prevention and treatment. Antiplatelet drugs such as aspirin and P2Y12 inhibitors are commonly used to reduce the risk of thrombotic events, including myocardial infarction, stroke, and stent thrombosis. However, the benefits associated with the use of antiplatelet drugs also come with a risk of bleeding complications. The ever-growing understanding of the poor prognostic implications associated with bleeding has set the foundations for defining strategies that can mitigate such safety concern without any trade-off in antithrombotic protection. To this extent, personalised antiplatelet therapy has emerged as a paradigm that optimizes the balance between safety and efficacy by customizing treatment to the individual patient's needs and risk profile. Accurate risk stratification for both bleeding and thrombosis can aid in selecting the optimal antiplatelet therapy and prevent serious and life-threatening outcomes. Risk stratification has traditionally included clinical and demographic characteristics and has expanded to incorporate angiographic features and laboratory findings. The availability of bedside platelet function testing as well as rapid genotyping assays has also allowed for a more individualized selection of antiplatelet therapy. This review provides a comprehensive overview of the current state of the art and future trends in personalised antiplatelet therapy for patients with CAD, with emphasis on those presenting with an acute coronary syndrome and undergoing percutaneous coronary revascularization. The aim is to provide clinicians with a comprehensive understanding of personalised antiplatelet therapy and facilitate informed clinical decision-making.
Genetic, sociodemographic, lifestyle, and clinical risk factors of recurrent coronary artery disease events: a population-based cohort study
Authors: Cho So Mi Jemma , Koyama Satoshi , Honigberg Michael C , Surakka Ida , Haidermota Sara , Ganesh Shriienidhie , Patel Aniruddh P , Bhattacharya Romit , Lee Hokyou , Kim Hyeon Chang , Natarajan Pradeep
Published: June 2023

Aims

Complications of coronary artery disease (CAD) represent the leading cause of death among adults globally. This study examined the associations and clinical utilities of genetic, sociodemographic, lifestyle, and clinical risk factors on CAD recurrence.

Methods and results

Data were from 7024 UK Biobank middle-aged adults with established CAD at enrolment. Cox proportional hazards regressions modelled associations of age at enrolment, age at first CAD diagnosis, sex, cigarette smoking, physical activity, diet, sleep, Townsend Deprivation Index, body mass index, blood pressure, blood lipids, glucose, lipoprotein(a), C reactive protein, estimated glomerular filtration rate (eGFR), statin prescription, and CAD polygenic risk score (PRS) with first post-enrolment CAD recurrence. Over a median [interquartile range] follow-up of 11.6 [7.2–12.7] years, 2003 (28.5%) recurrent CAD events occurred. The hazard ratio (95% confidence interval [CI]) for CAD recurrence was the most pronounced with current smoking (1.35, 1.13–1.61) and per standard deviation increase in age at first CAD (0.74, 0.67–0.82). Additionally, age at enrolment, CAD PRS, C-reactive protein, lipoprotein(a), glucose, low-density lipoprotein cholesterol, deprivation, sleep quality, eGFR, and high-density lipoprotein (HDL) cholesterol also significantly associated with recurrence risk. Based on C indices (95% CI), the strongest predictors were CAD PRS (0.58, 0.57–0.59), HDL cholesterol (0.57, 0.57–0.58), and age at initial CAD event (0.57, 0.56–0.57). In addition to traditional risk factors, a comprehensive model improved the C index from 0.644 (0.632–0.654) to 0.676 (0.667–0.686).

Conclusion

Sociodemographic, clinical, and laboratory factors are each associated with CAD recurrence with genetic risk, age at first CAD event, and HDL cholesterol concentration explaining the most.