bluuebunny/crossref_metadata_2025 huggingface dataset:
Ca2+permeation through C-terminal cleaved, but not full-length human Pannexin1 hemichannels, mediates cell death
Authors: Salgado Magdiel , Márquez-Miranda Valeria , Ferrada Luciano , Rojas Maximiliano , Poblete-Flores Gonzalo , González-Nilo Fernando D. , Ardiles Álvaro O. , Sáez Juan C.
Published: June 2024

Pannexin1 hemichannels (Panx1 HCs) are found in the membrane of most mammalian cells and communicate the intracellular and extracellular spaces, enabling the passive transfer of ions and small molecules. They are involved in physiological and pathophysiological conditions. During apoptosis, the C-terminal tail of Panx1 is proteolytically cleaved, but the permeability features of hemichannels and their role in cell death remain elusive. To address these topics, HeLa cells transfected with full-length human Panx1 (fl-hPanx1) or C-terminal truncated hPanx1 (Δ371hPanx1) were exposed to alkaline extracellular saline solution, increasing the activity of Panx1 HCs. The Δ371hPanx1 HC was permeable to DAPI and Etd+, but not to propidium iodide, whereas fl-hPanx1 HC was only permeable to DAPI. Furthermore, the cytoplasmic Ca2+signal increased only in Δ371hPanx1 cells, which was supported by bioinformatics approaches. The influx of Ca2+through Δ371hPanx1 HCs was necessary to promote cell death up to about 95% of cells, whereas the exposure to alkaline saline solution without Ca2+failed to induce cell death, and the Ca2+ionophore A23187 promoted more than 80% cell death even in fl-hPanx1 transfectants. Moreover, cell death was prevented with carbenoxolone or10Panx1 in Δ371hPanx1 cells, whereas it was undetectable in HeLa Panx1−/−cells. Pretreatment with Ferrostatin-1 and necrostatin-1 did not prevent cell death, suggesting that ferroptosis or necroptosis was not involved. In comparison, zVAD-FMK, a pancaspase inhibitor, reduced death by ~60%, suggesting the involvement of apoptosis. Therefore, alkaline pH increases the activity of Δ371hPanx1HCs, leading to a critical intracellular free-Ca2+overload that promotes cell death.
Tilted Perpendicular Anisotropy-Induced Spin-Orbit Ratchet Effects
Authors: Chen 陈 Bin 彬 , Long 龙 Yuantu 垣图 , Nie 聂 Yulin 宇林 , Ling 凌 Ziyu 姿瑀 , Ma 马 Tianping 天平 , Zhang 张 Ruixuan 瑞轩 , Wu 吴 Yizheng 义政 , Luo 骆 Yongming 泳铭 , Wang 王 Ningning 宁宁
Published: June 2024

Using micromagnetic simulations, we demonstrate the tilted perpendicular anisotropy-induced spin-orbit ratchet effect. In spin-orbit torque (SOT)-induced magnetization switching, the critical currents required to switch between the two magnetization states (upward and downward magnetization) are asymmetric. In addition, in the nanowire structure, tilted anisotropy induces formation of tilted domain walls (DWs). The tilted DWs exhibit a ratchet behavior during motion. The ratchet effect during switching and DW motions can be tuned by changing the current direction with respect to the tilting direction of anisotropy. The ratchet motion of the DWs can be used to mimic the leaky-integrate-fire function of a biological neuron, especially the asymmetric property of the “potential” and “reset” processes. Our results provide a full understanding of the influence of tilted perpendicular anisotropy on SOT-induced magnetization switching and DW motion, and are beneficial for designs of further SOT-based devices.
Comparative analysis of dark energy compact stars inf(T,T)and f(T) gravity theories via conformally flat condition
Authors: Ditta Allah , Mustafa G , Maurya S K , Sofuoğlu Değer , Mahmood Asif
Published: June 2024

This manuscript is the first investigation of dark energy celestial phenomena in the modified gravity theory by examining dark energy compact stars within the context of modifiedf(T,T)gravity. In order to compare the outcomes of thef(T,T)andf(T) gravity theories, the modelf(T,T)=αT(r)+βT(r)+ϕis selected. This model is then simplified tof(T) gravity by settingβ = 0. Thef(T) gravity is torsion-based gravity, while inf(T,T) gravity trace of energy-momentum tensor is coupled with torsion. Moreover, we note that we have more dense object formation inf(T,T)gravity as compared tof(T)-gravity. The spherically symmetric space-time inside the internal geometry is analyzed using a conformally flat condition, while the Schwarzschild geometry represents the outer space-time. Numerous characteristics of dark energy stars are examined, including equation of state components, energy conditions, and dark energy pressure components. Empirical evidence for the existence of dark energy in stellar configurations is presented by the results for pressure components in dark energy, which show a significant negative tendency in these stellar parameters. A complete analysis is performed by thoroughly investigating energy conditions, pressure profiles, sound speeds, gradients, adiabatic index, Tolman–Oppenheimer–Volkoff equation, mass function, compactness, and redshift function. The mass-radius relation is also discussed viaM − Rcurves. This confirms that the studied star configuration is realistic and acceptable.
Insights into molecular and bulk mechanical properties of glassy carbon through molecular dynamics simulations and mechanical tensile testing
Authors: Kunte Manali , Chanfón Lucía Carballo , Nimbalkar Surabhi , Bunnell James , Rodriguez Barajas Emanuel , Vazquez Mario Enrique , Trejo-Rodriguez David , Faucher Carter , Smith Skelly , Kassegne Sam
Published: June 2024

With increasing interest in the use of glassy carbon (GC) for a broad range of application areas, the need for developing a fundamental understanding of its mechanical properties has come to the forefront. Furthermore, recent theoretical and modeling works that highlight the synthesis of GC via the pyrolysis of polymer precursors has explored the possibilities of a revisit to the investigation of their mechanical properties at a fundamental level. Although there are isolated reports on the experimental determination of its elastic modulus, insights into the stress-strain behavior of a GC material under tension and compression obtained through simulations, either at the molecular level or for the bulk materials, are missing. This study fills the gap at the molecular level and investigates the mechanical properties of GC using molecular dynamics (MD) simulations, which model the atomistic-level formation and breaking of bonds using bond-order-based reactive force field formulations. The molecular model considered in this simulation has a characteristic 3D cage-like structure of five-, six-, and seven-membered carbon rings and graphitic domains of a flat graphene-like structure. The GC molecular model was subjected to loading under varying strain rates (0.4, 0.6, 1.25, and 2.5 ns−1) and temperatures (300 K–800 K) in each of the three axes: x, y, and z. The simulations show that the GC nanostructure has distinct stress-strain curves under tension and compression. In tension, MD modeling predicted a mean elastic modulus of 5.71GPa for a single GC nanostructure with some dependency on the strain rate and temperature, whereas, in compression, the elastic modulus was also found to depend on the strain rate and temperature and was predicted to have a mean value of 35 GPa. To validate the simulation results and develop experimental insights into the bulk behavior, mechanical tests were conducted on dog-bone-shaped testing coupons that were subjected to uniaxial tension and loaded until failure. The GC test coupons demonstrated a bulk modulus of 17 ±2.69 GPa in tension, which compares well with those reported in the literature. However, comparing MD simulation outcomes to those of uniaxial mechanical testing reveals that the bulk modulus of GC in tension found experimentally is higher than the modulus of single GC nanostructures predicted by MD modeling, which inherently underestimates the bulk modulus. With regard to failure modes, the MD simulations predicted failure in tension accompanied by the breaking of carbon rings within the molecular structure. In contrast, the mechanical testing demonstrated that failure modes are dominated by brittle failure planes largely due to the amorphous structure of GC.
Precise orbit determination of the LuTan satellite using GPS, BDS-2, and BDS-3 signals
Authors: Zhang Yu , Zhao Qile , Jiang Kecai , Guo Xiang , Lian Yidu , Li Min
Published: June 2024

The LuTan satellite is the first formation-flying mission of China enabling synthetic aperture radar interferometry in the L-band. As a key mission requirement, the absolute position of each satellite must be determined with an accuracy of 5 cm in three dimensions (3D). To fulfill this demand, each satellite carries a Global Positioning System/Beidou Navigation Satellite System (GPS/BDS) dual-constellation Global Navigation Satellite System receiver that can simultaneously track the GPS L1 and L2 signals, the BDS-2 B1I and B3I signals (BD2), and the BDS-3 B1C and B2a signals (BD3). In this study, we assess the performances of precise orbit determination with different signals and their combinations. For that purpose, we produce a total of five sets of orbit solutions, i.e., GPS-based, BD2-based, BD3-based, GPS/BD2 combined, and GPS/BD3 combined solutions. To evaluate the orbit solutions, comparisons in the orbital overlaps and with the GPS-based orbit are adopted. The orbital overlap analysis shows that the GPS-based solution has the smallest root mean square (RMS) of overlap orbit differences than other single-constellation solutions with 3.7 mm in 3D. The BD2- and BD3-based orbits are suffered from large errors and the overlap RMS differences are 24.7 and 18.9 mm, respectively. Furthermore, all of the combined orbits (both 3.1 mm for the GPS/BD2 and GPS/BD3 combined orbits) based on the variance component estimation method can obtain improvement than GPS-based solutions. For orbit comparisons, the GPS-based solution is selected to serve as the reference. The RMS values of the orbit differences are 29.9 and 15.4 mm for the BD2- and BD3-based solutions, respectively. For the GPS/BD2 and GPS/BD3 combined solutions, the values are 4.1 and 4.8 mm. In general, the results agree with those obtained in the overlap analysis. These results indicate that the BD3-based orbit is superior to the BD2-based orbit, while both of them are inferior to the GPS-based orbit. We show that inaccurate ephemerides of the BDS satellites can partly explain the degraded performance of the BDS-derived orbits. Nevertheless, the orbits still fulfill the 5 cm accuracy demand and can be readily used for subsequent precise baseline determination.
PSD estimation and modal parameter identification for random vibrations with blade tip timing measurement
Authors: Chai Pengfei , Wang Shang , Xiao Zhicheng , Meng Yiming , Tian Jie , Ouyang Hua
Published: June 2024

Blade tip timing (BTT) is a vibration measurement technique for blade health monitoring. Most of the existing BTT analysis methods are suitable for deterministic vibration signals but are ineffective for random vibration signals that often occur in practice. Statistical analysis of BTT data is significant for random vibration analysis and improving blade monitoring efficiency. This study proposes a compressive model for power spectral density (PSD) estimation and modal parameter identification. The efficiencies of three compressive sensing algorithms, including the least absolute shrinkage and selection operator (Lasso), nonnegative least squares (NLS), and nonnegative orthogonal matching pursuit, are compared. The effects of the duration of the signal and the frequency resolution on the quality of the estimated PSD and the identified parameters are discussed. According to the analysis, to obtain accurate damping ratios, it is recommended that the duration of the signal be greater than 3000 revolutions. A Q criterion based on the half-power bandwidth is proposed to determine the set of frequency resolutions. Numerical and field tests were conducted to verify the proposed method. The results indicate that the NLS algorithm is recommended to use. The root-mean-square errors of the identified natural frequencies and damping ratios obtained by the proposed method were 0.065 Hz and 0.023%, respectively. The proposed method was verified at different rotational speeds in a field test, demonstrating the capability of the method over a wide rotational speed range and providing more opportunities to detect blade damage.
Directly-excited laser-induced thermal grating spectroscopy and thermometry with carbon dioxide vibrational transition
Authors: Song Zihao , Zhu Ning , Wang Weitian , Sahlberg Anna-Lena , Chao Xing
Published: June 2024

Laser-induced thermal grating spectroscopy (LITGS) has been proved for accurate thermometry and measurement of energy transfer processes in molecules. While electronic transitions are often used for excitation in previous LITGS works, here we report laser-induced thermal gratings formed by direct excitation of CO2 with an infrared (IR) laser at wavelength near 2 μm, with which high signal-to-noise ratio LITGS signals are generated (SNR ∼ 300 at room temperature). A theoretical LITGS model assuming a ‘two-steps’ energy transfer process is used to describe the recorded signal waveform, with relative fitting residuals of less than 10%. Quantitative thermometry is performed in CO2 gas flows between 293 K and 420 K, with a relative uncertainty of 1.6% and a precision of 1.1% defined as the 1-σ standard deviation of 30 repeated measurement. Furthermore, the time constants of vibrational energy transfer at different temperatures are extracted from the temporal signal waveform with a precision better than 80 ns, and the measured results are consistent with the simulation using a detailed vibrational energy transfer model. These results demonstrate IR LITGS as a potential tool for spatially-resolved measurement of the thermophysical properties of fluids, as well as molecular vibrational energy transfer processes.
Accurate extrinsic calibration for the invisible-light 1D laser rangefinder and camera
Authors: Pu Yuchi , Ren Chaofeng , Yang Xinhui , Jin Feng , Jiao Yuhang , Li Shiyuan
Published: June 2024

A combined sensor, comprising a camera and a one-dimensional laser rangefinder (1D LRF), has wide application across engineering sectors, notably in aerospace. This combined sensor is pivotal for earth observation and deep space exploration. To achieve precise and stable external parameters for this combined sensor, an accurate external calibration method is proposed. Initially, a technique for localized registration of laser spots is introduced to ensure precise determination of their positions, addressing the challenge of laser invisibility in a 1D LRF. Subsequently, a data evaluation criterion known as the data synthesis criterion is presented, addressing the issue of limited constraints in traditional calibration methods. This criterion evaluates relative errors encompassing 1D LRF ranging values, camera external parameters, and laser spot positions. Finally, based on the proposed criteria, a robust extrinsic calibration method is introduced that automatically filters observation data with significant errors and utilizes the growth rate of camera spatial resolution as the termination condition. The efficacy of the proposed method is confirmed through simulation experiments and real-world data experiments.
Refraction color based contact detection for single cell micromanipulation: a cornerstone for precise automation
Authors: Qiu Jianxiong , Chen Anqi , Yan Mingyue , Zhi Pengxiang , Ye Yaling , Li Gangqiang , Wen Luhong
Published: June 2024

Single cell studies represent a cutting-edge field in life science. For cells growing on a soft substrate, a precise micromanipulation is indispensable in order for high-quality single-cell sampling. The foundation of micromanipulation is the accurate triaxial movement control, of which the major challenge lies in the z-axis positioning. Conventional methods rely on manual operation but are hampered by low efficiency. Resorting to additional sensors and cameras might help, whereas the system configuration becomes inevitably complicated. In this work, a vision-based approach utilizing interface refraction color is reported. By monitoring the color change induced by refraction during the contact process, we realized an accurate movement control of the end-effector. The reported method is capable of detecting the z-axis contact between the capillary tip and the substrate in a fully automated manner. Tested by 70 batches of a total of 3840 images, the proposed technique achieves an overall accuracy of 94.28% with precision of 2.73 μm, sufficing in the applications of single cell sampling. Detecting z-axis contact by interface refraction color marks an innovative computer vision method and it is proposed and validated in this work. Our method holds a promise of being a potent part of a close-loop control mechanism for automated single cell micromanipulation.
A method for the simultaneous determination of the soil dry density and moisture content based on thermal effects
Authors: Zeng Zizhen , Chen Jiang , Xiong Feng
Published: June 2024

The thermodynamic parameters of soil are affected by both dry density and moisture content, leading to uncertainty in measuring moisture content using the heat source method. This study proposes a combined approach using a back propagation (BP) neural network and the point heat resource method to simultaneously determine soil dry density and moisture content. The segmented mean value extracted from the temperature time-history data during the cooling process of the heat source serves as the feature input, while measured values of dry density and moisture content serve as outputs. A calibrated BP neural network model is trained and utilized for simultaneous determination of both parameters. Numerical simulations and modeling tests demonstrate good agreement between inverse identification results and measurements, with root mean square errors of 1.65% for moisture content and 34.09 kg∙m−3 for dry density, along with coefficients of determination at 0.9482 and 0.9359 respectively. It is proved that the method combining soil thermal effect and BP neural network to measure soil dry density and moisture content is feasible.
Potentiality of phosphide-based nanotubes for breast cancer detection: A DFT investigation
Authors: Rahman Aoly Ur , Saaduzzaman D M , Hasan Syed Mahedi , Sikder Md Kabir Uddin
Published: June 2024

Breast cancer is one of the most basilisk cancers for women due to its high mortality rate which can be prevented drastically with early-stage detection. In this work, the adsorption mechanism of two volatile organic compounds that are present in the breath of breast cancer patients, 2-Methyloctane and 3, 3-Dimethylpentane, has been investigated on aluminum phosphide nanotubes (AlPNT) and gallium phosphide nanotubes (GaPNT) in order to understand their feasibility as sensor materials to diagnosis breast cancer at early stage. We have used the quantum mechanical approach by employing density functional theory using B3LYP-D3 hybrid potential for noncovalent interaction along with the LanL2DZ basis in the Gaussian 09 software package. The adsorption properties analyses suggest that GaPNT exhibits better sensing behavior as well as proclaims 12.6% greater adsorption energy for 2-Methyloctane and 9.4% greater adsorption energy for 3, 3-Dimethylpentane than AlPNT. Other structural and electric properties analyses satisfy this conclusion and suggest that GaPNT exhibits higher stability than AlPNT and could possibly be a potential candidate for developing biosensors to detect breast cancer at the preliminary stages.
A greedy regularized block Kaczmarz method for accelerating reconstruction in magnetic particle imaging
Authors: Shen Yusong , Zhang Liwen , Zhang Hui , Li Yimeng , Zhao Jing , Tian Jie , Yang Guanyu , Hui Hui
Published: June 2024

Objective. Magnetic particle imaging (MPI) is an emerging medical tomographic imaging modality that enables real-time imaging with high sensitivity and high spatial and temporal resolution. For the system matrix reconstruction method, the MPI reconstruction problem is an ill-posed inverse problem that is commonly solved using the Kaczmarz algorithm. However, the high computation time of the Kaczmarz algorithm, which restricts MPI reconstruction speed, has limited the development of potential clinical applications for real-time MPI. In order to achieve fast reconstruction in real-time MPI, we propose a greedy regularized block Kaczmarz method (GRBK) which accelerates MPI reconstruction. Approach. GRBK is composed of a greedy partition strategy for the system matrix, which enables preprocessing of the system matrix into well-conditioned blocks to facilitate the convergence of the block Kaczmarz algorithm, and a regularized block Kaczmarz algorithm, which enables fast and accurate MPI image reconstruction at the same time. Main results. We quantitatively evaluated our GRBK using simulation data from three phantoms at 20 dB, 30 dB, and 40 dB noise levels. The results showed that GRBK can improve reconstruction speed by single orders of magnitude compared to the prevalent regularized Kaczmarz algorithm including Tikhonov regularization, the non-negative Fused Lasso, and wavelet-based sparse model. We also evaluated our method on OpenMPIData, which is real MPI data. The results showed that our GRBK is better suited for real-time MPI reconstruction than current state-of-the-art reconstruction algorithms in terms of reconstruction speed as well as image quality. Significance. Our proposed method is expected to be the preferred choice for potential applications of real-time MPI.
A comprehensive assessment of a prototype high ratio antiscatter grid in interventional cardiology using experimental measurements and Monte Carlo simulations
Authors: Massera Rodrigo T , Dehairs Michiel , Verhoeven Hannelore , Bosmans Hilde , Marshall Nicholas
Published: June 2024

Objective. To assess the performance of a new antiscatter grid design in interventional cardiology for image quality improvement and dose reduction using experimental measurements and Monte Carlo (MC) simulation. Approach. Experimental measurements were performed on an angiography system, using a multi-layered tissue simulating composite phantom made from of poly(methyl methacrylate), aluminium and expanded polystyrene (2/0.2/0.7 cm). The total phantom thickness ranged from 20.3 cm to 40.6 cm. Four conditions were compared; (A) 105 cm source-image receptor distance (SID) without grid, (B
i) 105 cm SID with grid ratio (r) and strip density (N) (r15N80), (B
ii) 120 cm SID without grid, and (Biii) 120 cm SID with high ratio grid (r29N80). The system efficiency (η), defined by the signal-to-noise ratio, was compared from the B conditions against case A. These conditions were also simulated with MC techniques, allowing additional phantom compositions to be explored. Weighted image quality improvement factor (ηw
(u)) was studied experimentally at a specific spatial frequency due to the SID change. Images were simulated with an anthropomorphic chest phantom for the different conditions, and the system efficiency was compared for the different anatomical regions. Main results. Good agreement was found between the η and ηw
(u) methods using both measured and simulated data, with average relative differences between 2%–11%. Case B
iii provided higher η values compared to A, and B
i for thicknesses larger than 20.3 cm. In addition, case B
iii also provided higher η values for high attenuating areas in the anthropomorphic phantom, such as behind the spine. Significance. The new antiscatter grid design provided higher system efficiency compared to the standard grid for the parameters explored in this work.
A particle jamming soft gripper integration of annular microwedge adhesion
Authors: Liu Huimin , Cui Jing , Zhang Bolun , Li Minghao , Cai Jiazhen , Chu Zhongyi
Published: June 2024

A key challenge in robotics is developing efficient methods for grasping objects of different shapes, sizes, poses, and properties. In this study, we propose a positive pressure actuation gripper that combination of annular microwedge adhesion and particle jamming. The gripper comprises an elastic membrane enclosing a mass of granular material, allowing for control of the backing stiffness during contact. In the inflated state, the elastic membrane is stretched, generating centripetal loading force for annular microwedge adhesion. By transitioning into a negative pressure jammed state, a rigid backing stiffness is achieved to maintain adhesion stability, later reverting to atmospheric pressure enables the gripper to release the object. Consequently, this gripper through annular microwedge adhesion offers controllable adhesion for grip and release a wide range of objects that are typically challenging for current soft grippers, such as flat objects, soft objects, or objects with complex geometries. We fabricate the positive pressure actuation gripper and clarify its working mechanism for both flat and curved surfaces. Furthermore, a theoretical analysis is carried out to calculate the frictional stress of the elastic membrane when it is in contact with an object. Experimental results on contact area demonstrate the feasibility of positive pressure actuation mechanism for annulus microwedge adhesion. The payload test determines the parameters of the elastic membrane with the best adhesion performance. The final demonstration shows the applicability of this soft gripper in various scenarios.
A novel modeling approach for the magnetorheological brake system based on improved LSTM
Authors: Lu He , Peng Lai , Hua Dezheng , Liu Xinhua , Yao Rongbin
Published: June 2024

In order to model the magnetorheological brake system under long-term operation and different working conditions, a novel performance prediction approach based on an improved long short term memory (LSTM) model is proposed to solve this problem. The framework of the proposed approach is presented, and an improved sparrow search algorithm is designed to optimize the hyperparameters of LSTM. Moreover, the proposed prediction approach based on improved LSTM is designed and the flowchart of this approach is shown. In addition, the first simulation example was carried out to demonstrate the effectiveness of the proposed model compared with the artificial neural network model and the conventional geometric model. Finally, the other simulation example was designed to exhibit the superior performance of the proposed algorithm compared with other algorithms.
Developing self-calibrating system for fiber Bragg grating based guided wave sensing under changing temperature conditions
Authors: Soman Rohan , Kudela Pawel
Published: June 2024

Fiber Bragg grating (FBG) sensors have long been thought of as the ideal sensors for structural health monitoring (SHM) due to their small size, light weight, ability to be embedded and ability to be multiplexed. So, FBG sensors have been commonly used for strain based SHM. In recent times, a renewed interest is seen in the use of FBG sensors for guided wave (GW) measurements using the edge filtering approach which increases the sensitivity several folds. They offer several unique opportunities for GW based SHM such as allowing mode filtering, acoustic coupling, etc. Unfortunately, more wide spread research is limited by the steep learning curve. Also, the use of FBG in real applications is still in its infancy due to the need of calibration of the system when the ambient temperature conditions change. This paper precisely tries to address these two shortcomings. For overcoming the steep learning curve, a detailed discussion on the hardware for the FBG based GW sensing is provided. Following the discussion a step-by-step approach is outlined for incorporating the sensors. A detailed trouble-shooting guide is developed based on the immense experience of the authors in this field. This exercise will allow easier adoption of the technique and stimulate more research in the topic. The exercise also allows us to highlight the safeguards and the features that need to be included in the system which will be self-calibrating. Once the design parameters are established a self-calibrating autonomous FBG based sensing system is developed. The developed system is tested in ambient conditions over an extended period in the day capturing the ambient temperature changes. The system is also tested in a larger temperature range (25 ∘C–65 ∘C). The results indicate that indeed the self-calibrating system works effectively. Some sensitivity studies to determine the performance in terms of system reaction time have also been provided. Such a ‘smart’ autonomous system for GW sensing has not been presented to the best of the author’s knowledge and is the key novelty of the presented work. Furthermore, the detailed discussions and troubleshooting guide will help introduce more people to this field of study which will lead to more radical development of the field.
Amorphous B coated Mg nanopowder induces low angle grain boundaries and enhances J
c of MgB2 wire
Authors: Xi Dan , Cai Xinwei , Wang Qingyang , Guo Chen , Li Li , Song Meng , Zhang Yan , Wang Dongliang , Ma Yanwei , Yan Guo , Wang Furen , Gan Zizhao
Published: June 2024

In this work, amorphous B coated Mg nanopowder (BCMN) is synthesized and transport property of MgB2 superconducting wire is significantly enhanced with different contents of BCMN. BCMN has high reactivity since it contains nanoscale Mg and amorphous B. It allows to obtain MgB2 nanocrystals at only 400 °C with the compression of a lattice parameter and expansion of c lattice parameter compared to MgB2 formed by micron-sized Mg mixed with amorphous B (Mg + B) powders. These MgB2 nanocrystals serve as crystal nuclei and promote the crystallization and growth of MgB2. The mismatch of different lattice parameters prepared using BCMN and M + B powders induces low angle grain boundaries (LAGBs) embedded in MgB2 grains. LAGBs act as plane defects, leading to a dominant surface pinning mechanism and an enhancement in the critical current density on the magnetic field (J
c(H)). At 4.2 K in 6 T, transport critical current density (J
ct) of wire with 20 wt.% BCMN is 6.7 × 104 A·cm−2, approximately 1.8 times wire with 0 wt.% BCMN.
Spatial coherent manipulation of Bessel-like vector vortex beam in atomic vapor
Authors: Zeng Xinji , Li Zhuang , Yang Xin , Xu Jianyi , Wang Jinwen , Wang Chengyuan , Quan Quan , Chen Haixia , Wei Dong , Gao Hong , Li Fuli
Published: June 2024

The interaction between vector beams and atoms under a weak magnetic field could induce spatially dependent electromagnetically induced transparency (EIT). Based on such a coherence effect, we propose a method for manipulating vector beams carrying spiral varying phases in hot rubidium atoms. When a transverse magnetic field (TMF) is applied, the transparent regions of the transmitted beam are strongly depend on the beam’s polarization distribution. In addition to the intensity modulation, the alignment of the TMF is reflected in the rotation of the central symmetric transmission patterns. In theory, we discuss the physical mechanism of the spiral EIT region generated by the phase profile, and analyze the influence of system parameters on this coherent process. Our work confirms that introducing additional radial phases can also lead to spatially dependent EIT, which extends another degree of freedom to manipulate atomic polarization. This will provide potential applications in light field manipulation and multi-dimensional quantum storage.
Analysis of shock wave propagation in the atmosphere through generated sound waves
Authors: Harutyunyan G.A. , Muradyan A.A. , Aramyan A.R. , Alexanyan H.A. , Sargsyan N.H. , Mkrtchyan L.S. , Harutyunyan V.G. , Khachikyan L.E.
Published: June 2024

The paper presents the results of studies of shock waves propagating in the atmosphere. These results were obtained by recording sound waves generated by a shock wave. It has been shown that it takes approximately two seconds for a shock wave to form. The frequency of the sound wave generated by the shock wave depends on the speed of propagation of the shock wave. It was found that the shock wave accelerates as it propagates upward. This phenomenon can be used as a method for determining the velocities of shock waves or supersonic moving bodies.
X-ray study of the density distribution of FFF-printed samples with different fill patterns
Authors: Bulavskaya A. , Bushmina E. , Grigorieva A. , Miloichikova I. , Stuchebrov S.
Published: June 2024

Three-dimensional printing has a wide range of applications in science and
technology. Fused filament fabrication (FFF) is a commonly used 3D printing technology, which is
now being increasingly employed in radiation physics. In FFF, the internal structure of an object
is primarily determined by its fill pattern and selected print modes. Therefore, this study aims
to examine the interaction between X-rays and 3D-printed plastic samples with various infill
patterns. The 3D-printed objects were produced using FFF with plastic and different infill
patterns, including Rectilinear, Grid, Triangles, Stars, Honeycomb, Concentric, Archimedean
Chords, Gyroid, and Hilbert Curve. Infill densities of 80% and 90% were utilized. Tomographic
methods were applied to analyze the resulting samples. The study provides tomograms of the
internal structure for each infill pattern. It was observed that Rectilinear and Grid patterns
produced the most homogeneous samples. The findings of this study contribute to understanding of
the propagation of X-rays through 3D-printed plastic samples with complex internal structures.
Holographic entanglement renormalisation for fermionic quantum matter
Authors: Mukherjee Abhirup , Patra Siddhartha , Lal Siddhartha
Published: June 2024

We demonstrate the emergence of a holographic dimension in a system of 2D non-interacting Dirac fermions placed on a torus, by studying the scaling of multipartite entanglement measures under a sequence of renormalisation group (RG) transformations applied in momentum space. Geometric measures defined in this emergent space can be related to the RG beta function of the spectral gap, hence establishing a holographic connection between the spatial geometry of the emergent spatial dimension and the entanglement properties of the boundary quantum theory. We prove, analytically, that changing the boundedness of the holographic space involves a topological transition accompanied by a critical Fermi surface in the boundary theory. We go on to show that this results in the formation of a quantum wormhole geometry that connects the UV and the IR of the emergent dimension. The additional conformal symmetry at the transition also supports a relation between the emergent metric and the stress-energy tensor. In the presence of an Aharonov–Bohm flux, the entanglement gains a geometry-independent piece which is shown to be topological, sensitive to changes in boundary conditions, and related to the Luttinger volume of the system. Upon the insertion of a strong transverse magnetic field, we show that the Luttinger volume is linked to the Chern number of the occupied single-particle Landau levels.
Gait dynamic stability evaluation in patients undergoing hip joint fractures – tools to measure rehabilitation effectiveness
Authors: Mahmood Imran , Maqbool Hafiz Farhan , Raza Anam , Iqbal Nadeem , Dehghani-Sanij Abbas A
Published: June 2024

A hip joint fracture includes a break in the thigh (femur) or coxa bone near the pelvis. During fracture healing, stability and weight bearing by the affected limb are key indicators to measure patients’ improvement. Conventionally, the rehabilitation effectiveness is monitored through clinical examinations, patients’ feedback, and few studies also reported instrumented gait evaluations. A gap remains there to numerically quantify the recovery in patients’ stability and weight bearing in response to rehabilitation therapies. This study introduces Nyquist and Bode (N&B) methods to analyse the instrumented gait signals further and evaluate gait stability in hip fracture patients during weight loading and unloading transitions. The centre of pressure (CoP) data was recorded using force plates for conditions: coxa hip fracture (HC), femur hip fracture (HF), and normal hip joint (NH). The time rate of CoP signals illustrated two major impulses during the loading and unloading phases which were modelled in time and frequency domains. The frequency models were further analysed by applying N&B methods and stability margins were computed for both impaired and healthy conditions. Results illustrated a significant decrease (Kruskal–Wallis’s test, p < 0.001) in the intralimb walking stability of both fracture conditions. Further, Spearman’s correlation between CoP velocities of fractured and intact limbs illustrated significant interlimb dependencies to maintain walking stability (p < 0.001) during weight loading and unloading transitions. Overall, the HF impairment illustrated the least intralimb walking stability and relatively greater interlimb dependencies. Clinically, these methods and findings are important to measure the recovery in patients undergoing rehabilitation after a hip joint or other lower limb impairments.
Dose equivalent consideration from neutron contamination in modified radiotherapy vault: a Monte Carlo study
Authors: Saadatmand Pegah , Mahdavi Seied Rabi , Chegeni Nahid , Karimi Amir Hossein
Published: June 2024

Laminated barriers incorporating metal sheets provide effective protection for space-restricted radiotherapy centers. This study aimed to assess photoneutron contamination in smaller vaults protected by different compositions of multilayer barriers during simulated pelvic radiotherapy with 18 MV photon beams. Monte Carlo Simulations of 18 MV LINAC (Varian 2100 C/D) and Medical Internal Radiation Dose (MIRD) phantom were used to assess photoneutron contamination within reconstructed vaults incorporating different combinations of metal sheet and borated polyethylene (BPE) during pelvic radiotherapy. The findings highlight a 3.27 and 2.91 times increase in ambient neutron dose

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(10) along the maze of reconstructed vaults that use lead and steel sheets, respectively, compared to concrete. The

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(10) outside the treatment room increased after incorporating a metal sheet, but it remained within the permissible limit of 20 μSv/week for uncontrolled areas adjacent to the LINAC bunker, even with a workload of 1000Gy/week. Neutron equivalent doses in the patient’s organs ranged from 0.22 to 0.96 mSv Gy−1. There is no notable distinction in the organ’s neutron equivalent dose, fatal cancer risk, secondary radiation-induced cancer risk, and cancer mortality for various laminated barrier compositions. Furthermore, the use of metal sheets for vault wall reconstruction keeps the variation in cancer risk induced by photoneutrons below 6%, while risks of fatal cancer and cancer mortality vary less than 11%. While the metal portion of the laminated barrier raises the neutron dose, the addition of a BPE plate reduces concerns of increased effective dose and secondary malignancy risk.
Lung sparing in MR-guided non-adaptive SBRT treatment of peripheral lung tumors
Authors: Lee Ho Young , Lee Grace , Ferguson Dianne , Hsu Shu-Hui , Hu Yue-Houng , Huynh Elizabeth , Sudhyadhom Atchar , Williams Christopher L , Cagney Daniel N , Fitzgerald Kelly J , Kann Benjamin H , Kozono David , Leeman Jonathan E , Mak Raymond H , Han Zhaohui
Published: June 2024

Objective. We aim to: (1) quantify the benefits of lung sparing using non-adaptive magnetic resonance guided stereotactic body radiotherapy (MRgSBRT) with advanced motion management for peripheral lung cancers compared to conventional x-ray guided SBRT (ConvSBRT); (2) establish a practical decision-making guidance metric to assist a clinician in selecting the appropriate treatment modality. Approach. Eleven patients with peripheral lung cancer who underwent breath-hold, gated MRgSBRT on an MR-guided linear accelerator (MR linac) were studied. Four-dimensional computed tomography (4DCT)-based retrospective planning using an internal target volume (ITV) was performed to simulate ConvSBRT, which were evaluated against the original MRgSBRT plans. Metrics analyzed included planning target volume (PTV) coverage, various lung metrics and the generalized equivalent unform dose (gEUD). A dosimetric predictor for achievable lung metrics was derived to assist future patient triage across modalities. Main results. PTV coverage was high (median V100% > 98%) and comparable for both modalities. MRgSBRT had significantly lower lung doses as measured by V20 (median 3.2% versus 4.2%), mean lung dose (median 3.3 Gy versus 3.8 Gy) and gEUD. Breath-hold, gated MRgSBRT resulted in an average reduction of 47% in PTV volume and an average increase of 19% in lung volume. Strong correlation existed between lung metrics and the ratio of PTV to lung volumes (RPTV/Lungs) for both modalities, indicating that RPTV/Lungs may serve as a good predictor for achievable lung metrics without the need for pre-planning. A threshold value of RPTV/Lungs < 0.035 is suggested to achieve V20 < 10% using ConvSBRT. MRgSBRT should otherwise be considered if the threshold cannot be met. Significance. The benefits of lung sparing using MRgSBRT were quantified for peripheral lung tumors; RPTV/Lungs was found to be an effective predictor for achievable lung metrics across modalities. RPTV/Lungs can assist a clinician in selecting the appropriate modality without the need for labor-intensive pre-planning, which has significant practical benefit for a busy clinic.
Interference voltage measurement and analysis of cardiac implants exposed to electric fields at extremely low frequency
Authors: Zhou Mengxi , Kourtiche Djilali , Claudel Julien , Deschamps Francois , Magne Isabelle , Roth Patrice , Schmitt Pierre , Nadi Mustapha
Published: June 2024

Objective. The possibility of interference by electromagnetic fields in the workplaces with cardiac implants is a concern for both individuals and employers. This article presents an analysis of the interference to which cardiac implants are subjected under high-intensity electric field at the power frequency. Approach. Evaluations of interference were conducted by studying the induced voltages at the device input in the real case study and the substitute study, and establishing an association between them with the equivalence factor F. A funnel-shaped phantom, designed for in vitro testing and representing the electrical characteristics of the locations where cardiac implants are installed, was used in the substitute study. A measuring system was implemented to measure the induced voltage at the device input under high intensity electric fields. Main results. The induced voltages obtained in the experimental measurements align with the findings of the numerical study in the phantom. By applying the equivalence factors derived between the real case study and the substitute study (2.39 for unipolar sensing; 3.64 for bipolar sensing), the induced voltages on the cardiac implants can be determined for the real case using the substitute experimental set-up. Significance. The interference voltages on the cardiac implants under electric field exposures at low frequency were experimentally measured with detailed description. The findings provide evidence for an analysis method to systematically study the electromagnetic interference on the cardiac implants at low frequency.
Simulation of charge-exchange induced NBI losses on EAST
Authors: LIN 林 Zhanhong 展宏 , WANG 王 Feng 丰 , XU 徐 Ming 明 , SANG 桑 Chaofeng 超峰 , ZHANG 张 Chen 晨 , WANG 王 Zhengxiong 正汹
Published: June 2024

The neutral beam injection is widely adopted in tokamaks as a key heating tool, playing a crucial role in generating burning plasmas. However, the loss of beam ions can damage the first wall and reduce the heating efficiency, resulting in failure to maintain steady-state conditions. In this work, the effect of neutral particles in the edge on fast ions generated by NBI in the Experimental Advanced Superconducting Tokamak (EAST) device is studied using the particle tracer code (PTC). The poloidal distribution of neutral particles is calculated by edge plasma simulation code SOLPS-ITER. In this simulation, four beam lines in EAST are considered: co-current tangential (co-tang), co-current perpendicular (co-perp), counter-current tangential (ctr-tang) and counter-current perpendicular (ctr-perp). It is shown that, in the absence of neutral particles, the loss fraction of ctr-injection is considerably higher than that of the co-injection. When considering the neutral particles, it is found that the ctr-perp injection demonstrates a significant variation in particles loss fraction (ranging from 18.56% to 25.42%) compared to the other three injection configurations. In terms of the loss fraction induced by neutral particles, ctr-injection exceeds co-injection, and perpendicular configuration exceeds tangential configuration. Furthermore, the difference of charge exchange ratios of three different energy (full energy, half energy, one third energy) of the four injections can be attributed to variations in the poloidal trajectories associated with each of these injections. Moreover, approximately half of fast ions which undergo neutralization directly lose to the first wall while the rest re-enter the bulk plasma and re-ionize. Except for the ctr-tang injection, the reionization ions from the other three injections exhibit effective confinement.
AI and the next medical revolution: deep learning’s uncharted healthcare promise
Authors: L B Krithika , S Vishnu , Kotei Evans , Gadde Ashok , Kothamasu Ganga Abhirup , Nallabantu Sri Charan , J Guruprakash
Published: June 2024

Deep learning has shown tremendous potential for transforming healthcare by enabling more accurate diagnoses, improved treatment planning and better patient outcome predictions. In this comprehensive survey, we provide a detailed overview of the state-of-the-art deep learning techniques and their applications across the healthcare ecosystem. We first introduce the fundamentals of deep learning and discuss its key advantages compared to traditional machine learning approaches. We then present an in-depth review of major applications of deep learning in medical imaging, electronic health record analysis, genomics, medical robotics and other domains. For each application, we summarize key advancements, outline the technical details of state-of-the-art methods, discuss challenges and limitations and highlight promising directions for future work. We examine cross-cutting challenges in deploying deep learning in clinical settings, including interpretability, bias and data scarcity. We conclude by proposing a roadmap to accelerate the translation and adoption of high-impact healthcare applications of deep learning. Overall, this survey provides a comprehensive reference for researchers and practitioners working at the intersection of deep learning and healthcare.
Track fastener detection in special scenarios based on TSR-Net
Authors: Bai Tangbo , Duan Jiaming , Fu Haochen , Zong Hao
Published: June 2024

The traditional method of detecting track fasteners can lead to erroneous results due to the presence of rail bolts, wires, and extraneous objects such as stones. Consequently, the study of fastener detection in specific environments is essential. To address these issues, the TSR-Net target detection model is introduced, which employs an efficient vision transformer as a backbone to increase the speed of feature extraction. The global image perception of the network is enhanced by integrating translation convolutions and inverted residual blocks within the neck network. A detection head with a self-supervised equivariant attention mechanism is designed to deal with the occlusion challenges of small fastener targets. The model is implemented on edge AI computing devices. Technical validation indicates that TSR-Net achieves 94.2% detection precision and operates at 47 frames per second, thereby enabling accurate, real-time detection of small-target occlusion fasteners.