bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of shear on nucleation and movement of basal plane dislocations in 4H-SiC
Authors: Yang Yanwei , Li Keqiang , Tong Zhouyu , Pi Xiaodong , Yang Deren , Huang Yuanchao
Published: July 2024

Basal plane dislocations (BPDs) are a key factor influencing the advancement of the 4H-SiC semiconductor. In this paper, the effects of shear forces on the nucleation and movement of BPDs are revealed by employing molecular dynamics simulations. The stress–strain curves of 4H-SiC subjected to different shear forces at different temperatures are obtained. It is found that the decrease in mechanical properties of 4H-SiC is mainly due to the occurrence of dislocation. This study also delves into the complexities of dislocation entanglement and slip, unraveling the impact on the mechanical properties of 4H-SiC. Moreover, the causes of dislocation within the crystal lattice were clarified from a microscopic atomic vantage point, shedding light on the intricate mechanisms involving chemical bond rupture and regeneration. These findings not only enrich our understanding of BPDs nucleation but also provide invaluable insights for mitigating BPDs in 4H-SiC.
Twins in rotational spectroscopy: Does a rotational spectrum uniquely identify a molecule?
Authors: Schwarting Marcus , Seifert Nathan A. , Davis Michael J. , Blaiszik Ben , Foster Ian , Prozument Kirill
Published: July 2024

Rotational spectroscopy is the most accurate method for determining structures of molecules in the gas phase. It is often assumed that a rotational spectrum is a unique “fingerprint” of a molecule. The availability of large molecular databases and the development of artificial intelligence methods for spectroscopy make the testing of this assumption timely. In this paper, we pose the determination of molecular structures from rotational spectra as an inverse problem. Within this framework, we adopt a funnel-based approach to search for molecular twins, which are two or more molecules, which have similar rotational spectra but distinctly different molecular structures. We demonstrate that there are twins within standard levels of computational accuracy by generating rotational constants for many molecules from several large molecular databases, indicating that the inverse problem is ill-posed. However, some twins can be distinguished by increasing the accuracy of the theoretical methods or by performing additional experiments.
Ultrafast green single photon emission from an InGaN quantum dot-in-a-GaN nanowire at room temperature
Authors: Bhunia Swagata , Majumder Ayan , Chatterjee Soumyadip , Sarkar Ritam , Nag Dhiman , Saha Kasturi , Mahapatra Suddhasatta , Laha Apurba
Published: July 2024

Single photon emitters, preferably working at room temperature, are crucial components of a diverse set of quantum technologies. Nanowire-supported quantum dots (NWQDs) of InGaN have emerged in the recent past as promising candidates of single photon emission (SPE) at visible wavelengths, though their efficient operation so far has been restricted to cryogenic temperatures. Here, we report the demonstration of visible-wavelength (λ=561 nm) SPE at room temperature, from specially designed InGaN NWQDs, wherein the second-order correlation function at zero-delay is measured to be the lowest reported so far (g2 (0) = 0.11), for this system. Using a single-step molecular-beam-epitaxy-based fabrication technique, we realized InGaN NWQDs with both lateral and vertical dimensions scaled down to the Bohr-radius limit. This achievement is responsible not only for the efficient single photon emission at room temperature but also for the reduction of carrier lifetimes to the order of several hundreds of picoseconds. The latter has been made possible by the suppression of the built-in polarization field, which is attributed to the strong radial confinement obtained in the NWQDs fabricated by our method. These InGaN NWQDs are thus extremely promising for the development of visible-wavelength single photon sources, operating at room temperature and GHz repetition rates.
Existence probabilities of single Si atoms diffusing in Si(111)-(7 × 7) half-unit cells at room temperature
Authors: Ueda K. , Diao Z. , Hou L. , Yamashita H. , Abe M.
Published: July 2024

We determined the probabilities of finding diffusing Si atoms in faulted and unfaulted half-unit cells on the Si(111)-(7 × 7) surface. An adsorbed Si atom on the surface at room temperature moved in the half-unit cells. The atom was adsorbed via atom manipulation and located via under-sampled scanning tunneling microscopy. Images of the half-unit cells with the diffusing Si atom and images of the clean surface were superimposed via image processing to calculate differences used to determine the Si atom positions at room temperature. There were different probabilities for Si atom diffusion in faulted and unfaulted half-unit cells.
Revisiting kinetic Monte Carlo algorithms for time-dependent processes: From open-loop control to feedback control
Authors: Chittari Supraja S. , Lu Zhiyue
Published: July 2024

Simulating stochastic systems with feedback control is challenging due to the complex interplay between the system’s dynamics and the feedback-dependent control protocols. We present a single-step-trajectory probability analysis to time-dependent stochastic systems. Based on this analysis, we revisit several time-dependent kinetic Monte Carlo (KMC) algorithms designed for systems under open-loop-control protocols. Our analysis provides a unified alternative proof to these algorithms, summarized into a pedagogical tutorial. Moreover, with the trajectory probability analysis, we present a novel feedback-controlled KMC algorithm that accurately captures the dynamics systems controlled by an external signal based on the measurements of the system’s state. Our method correctly captures the system dynamics and avoids the artificial Zeno effect that arises from incorrectly applying the direct Gillespie algorithm to feedback-controlled systems. This work provides a unified perspective on existing open-loop-control KMC algorithms and also offers a powerful and accurate tool for simulating stochastic systems with feedback control.
FeNNol: An efficient and flexible library for building force-field-enhanced neural network potentials
Authors: Plé Thomas , Adjoua Olivier , Lagardère Louis , Piquemal Jean-Philip
Published: July 2024

Neural network interatomic potentials (NNPs) have recently proven to be powerful tools to accurately model complex molecular systems while bypassing the high numerical cost of ab initio molecular dynamics simulations. In recent years, numerous advances in model architectures as well as the development of hybrid models combining machine-learning (ML) with more traditional, physically motivated, force-field interactions have considerably increased the design space of ML potentials. In this paper, we present FeNNol, a new library for building, training, and running force-field-enhanced neural network potentials. It provides a flexible and modular system for building hybrid models, allowing us to easily combine state-of-the-art embeddings with ML-parameterized physical interaction terms without the need for explicit programming. Furthermore, FeNNol leverages the automatic differentiation and just-in-time compilation features of the Jax Python library to enable fast evaluation of NNPs, shrinking the performance gap between ML potentials and standard force-fields. This is demonstrated with the popular ANI-2x model reaching simulation speeds nearly on par with the AMOEBA polarizable force-field on commodity GPUs (graphics processing units). We hope that FeNNol will facilitate the development and application of new hybrid NNP architectures for a wide range of molecular simulation problems.
Scalable piezoelectric energy harvesting from PVDF-HFP/BZT-BCT/GO hybrid composite film
Authors: Lipsa Loree , Parida Sabyasachi , Behura Sanjay K. , Choudhary Abhisek , Roy Amritendu
Published: July 2024

Considering the growing demand for piezoelectric energy harvesting from ferroelectric–polymer-based composite materials and the benefits associated with them, this work focuses on piezoelectric energy harvesting from poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP)/BZT-BCT/GO hybrid composite films synthesized via solution casting followed by the hot-pressing method. Structural properties were analyzed using XRD, FTIR, and Raman spectroscopy. SEM micrographs confirmed the presence of pores in the synthesized samples that provided an added advantage toward enhancing its piezoelectricity. The dielectric and ferroelectric properties were studied, in which the dielectric constant increased up to 20.69, and the remnant polarization was found to be 0.0560 μC cm−2. A PUND analysis was performed to validate the data obtained from the static hysteresis loop. Piezoelectric charge and voltage coefficients were measured, which reach up to “−31 pC N−1” and “−252.5 mV m N−1,” respectively. Figure of merit, electromechanical coupling coefficient, and quality factor of the as-synthesized samples were calculated. A harvester prototype was fabricated to investigate the energy harvesting performance of the synthesized hybrid composite films. The highest open circuit voltage, short circuit current, and power density were recorded as 2.19 V, 24.17 nA, and 468.43 μ W m−2, respectively. The harvested energy can be utilized for powering low-power devices, showing the real-time applicability of the synthesized hybrid composite films.
A new parameterization of the DFT/CIS method with applications to core-level spectroscopy
Authors: Mandal Aniket , Berquist Eric J. , Herbert John M.
Published: July 2024

Time-dependent density functional theory (TD-DFT) within a restricted excitation space is an efficient means to compute core-level excitation energies using only a small subset of the occupied orbitals. However, core-to-valence excitation energies are significantly underestimated when standard exchange–correlation functionals are used, which is partly traceable to systemic issues with TD-DFT’s description of Rydberg and charge-transfer excited states. To mitigate this, we have implemented an empirically modified combination of configuration interaction with single substitutions (CIS) based on Kohn–Sham orbitals, which is known as “DFT/CIS.” This semi-empirical approach is well-suited for simulating x-ray near-edge spectra, as it contains sufficient exact exchange to model charge-transfer excitations yet retains DFT’s low-cost description of dynamical electron correlation. Empirical corrections to the matrix elements enable semi-quantitative simulation of near-edge x-ray spectra without the need for significant a posteriori shifts; this should be useful in complex molecules and materials with multiple overlapping x-ray edges. Parameter optimization for use with a specific range-separated hybrid functional makes this a black-box method intended for both core and valence spectroscopy. Results herein demonstrate that realistic K-edge absorption and emission spectra can be obtained for second- and third-row elements and 3d transition metals, with promising results for L-edge spectra as well. DFT/CIS calculations require absolute shifts that are considerably smaller than what is typical in TD-DFT.
Exploring recursive properties and dynamical complexity in scalar time-series using threshold-free recursive analysis approach
Authors: Sun Guodong , Wang Haisheng , Wang Yuting , Jian Bobo
Published: July 2024

In this project, a threshold-free recursive analysis approach was investigated to reveal the recursive properties of dynamic systems. Specifically, the occurrence of recurrent patterns in phase trajectory was identified by a threshold-free recursive matrix whose elements would possess continuous values within the interval of [0, 1] and are inversely proportional to the distance between phase points. Subsequently, mapping and feature extraction were carried out to visualize and quantify the threshold-free recursive matrix. Theoretical time-series, along with observed time-series in the fields of engineering, finance, and hydrology, have been utilized to validate the efficacy of this approach. The results demonstrate the applicability of this method in analyzing the dynamic characteristics of scalar time-series. Furthermore, the rebuilt grayscale recurrence plot morphology and extracted measures through grayscale recurrence quantification analysis measures can effectively unveil the dynamical complexity of nonlinear systems by offering more precise analysis outcomes for investigating the evolution of recursive characteristics.
Identifying black rat (Rattus rattus) movement patterns aids the development of management programs in citrus orchards
Authors: Baldwin Roger A. , Meinerz Ryan , Smith Justine A.
Published: July 2024

Context The black rat (Rattus rattus) is an invasive species found throughout much of the globe, including in many agricultural areas, where they cause significant damage to many crops including citrus. Understanding how black rats move in these orchards would substantially aid the development of management programs to combat this pest species. Aim Our goal was to determine the home-range size and mean maximum distance moved over a 24-h period, as well as to determine the activity period for black rats in orchards. Methods We used innovative cellular tracking technology to provide a more complete assessment of home-range size and maximum daily movements than previously reported in other investigations. We also used remote-triggered cameras to assess activity periods for black rats to better inform management actions. Key results We observed large home ranges for black rats in citrus orchards ( x ¯ = 2.36     ha ). Although mean home-range size did not differ between males and females, we did identify an effect of sex on the mean maximum daily distance moved by black rats (males: x ¯ = 201     m ; females: x ¯ = 148     m ). Black rats were most active during the early evening, with all observations made during night-time. Conclusions Black rats moved relatively large distances within orchards, with activity occurring exclusively at night. Implications This information on black rat activity patterns will greatly assist in the development of management programs by informing ideal spacing between traps and bait stations to minimise cost, while still yielding efficacious results. A reliance on trapping or baiting during night-time would ensure access by black rats, while eliminating access to diurnal non-target species, although such actions would be labour-intensive and may be cost-prohibitive.
Coordination engineering for iron-based hexacyanoferrate as a high-stability cathode for sodium-ion batteries
Authors: Zhong Jiang , Xia Lirong , Chen Song , Zhang Zhengwei , Pei Yong , Chen Hao , Sun Hongtao , Zhu Jian , Lu Bingan , Zhang Yinghe
Published: July 2024

Iron-based hexacyanoferrate (Fe-HCF) are promising cathode materials for sodium-ion batteries (SIBs) due to their unique open-channel structure that facilitates fast ion transport and framework stability. However, practical implementation of SIBs has been hindered by low initial Coulombic efficiency (ICE), poor rate performance, and short lifespan. Herein, we report a coordination engineering to synthesize sodium-rich Fe-HCF as cathodes for SIBs through a uniquely designed 10-kg-scale chemical reactor. Our study systematically investigated the relationship between coordination surroundings and the electrochemical behavior. Building on this understanding, the cathode delivered a reversible capacity of 99.3 mAh g
−1
at 5 C (1 C = 100 mA g
−1
), exceptional rate capability (51 mAh g
−1
even at 100 C), long lifespan (over 15,000 times at 50 C), and a high ICE of 92.7%. A full cell comprising the Fe-HCF cathode and hard carbon (HC) anode exhibited an impressive cyclic stability with a high-capacity retention rate of 98.3% over 1,000 cycles. Meanwhile, this material can be readily scaled to the practical levels of yield. The findings underscore the potential of Fe-HCF as cathodes for SIBs and highlight the significance of controlling nucleation and morphology through coordination engineering for a sustainable energy storage system.
A theory of phonon-induced friction on molecular adsorbates
Authors: Farahvash Ardavan , Willard Adam P.
Published: July 2024

In this manuscript, we provide a general theory for how surface phonons couple to molecular adsorbates. Our theory maps the extended dynamics of a surface’s atomic vibrational motions to a generalized Langevin equation, and by doing so captures these dynamics in a single quantity: the non-Markovian friction. The different frequency components of this friction are the phonon modes of the surface slab weighted by their coupling to the adsorbate degrees of freedom. Using this formalism, we demonstrate that physisorbed species couple primarily to acoustic phonons while chemisorbed species couple to dispersionless local vibrations. We subsequently derive equations for phonon-adjusted reaction rates using transition state theory and demonstrate that these corrections improve agreement with experimental results for CO desorption rates from Pt(111).
Remodeling of perturbed chromatin can initiate de novo transcriptional and post-transcriptional silencing
Authors: Carlier Florian , Castro Ramirez Sebastian , Kilani Jaafar , Chehboub Sara , Loïodice Isabelle , Taddei Angela , Gladyshev Eugene
Published: July 2024

In eukaryotes, repetitive DNA can become silenced de novo, either transcriptionally or post-transcriptionally, by processes independent of strong sequence-specific cues. The mechanistic nature of such processes remains poorly understood. We found that in the fungus
Neurospora crassa
, de novo initiation of both transcriptional and post-transcriptional silencing was linked to perturbed chromatin, which was produced experimentally by the aberrant activity of transcription factors at the
tetO
operator array. Transcriptional silencing was mediated by canonical constitutive heterochromatin. On the other hand, post-transcriptional silencing resembled repeat-induced quelling but occurred normally when homologous recombination was inactivated. All silencing of the
tetO
array was dependent on SAD-6, fungal ortholog of the SWI/SNF chromatin remodeler ATRX (Alpha Thalassemia/Mental Retardation Syndrome X-Linked), which was required to maintain nucleosome occupancy at the perturbed locus. In addition, we found that two other types of sequences (the
lacO
array and native AT-rich DNA) could also undergo recombination-independent quelling associated with perturbed chromatin. These results suggested a model in which the de novo initiation of transcriptional and post-transcriptional silencing is coupled to the remodeling of perturbed chromatin.
Numerical simulation of a nebulizer with multiple orifices
Authors: Chen (陈泽譞) Zexuan , Butan Daniela , Clifford Seamus , Greaney Russell , Cunningham Sean , Griffin Philip
Published: July 2024

A vibrating mesh nebulizer is a medical device that can break liquid medication into an aerosol of tiny droplets so that patients can inhale them to treat diseases. The volumetric flow rate of this kind of nebulizer is determined by many factors, including the orifice geometry, the vibration amplitude and the vibration mode shape. Thus, many experiments were designed to assess the effects of these different variables on flow rate and to find the optimal set of device parameters that maximizes the flow rate. However, it can be very expensive to perform such physical experimentation with physical prototypes, which needs different orifice geometries to be fabricated for different test regimes. The orifice sizes are microscopic with diameters typically between 3 µm and 5 µm, thus, they are difficult to be fabricated with the exact shape and diameter that are required. Therefore, virtual prototyping by means of numerical simulation models are required as the orifice geometries and other factors can be easily changed in the simulation models. This study aims to provide a numerical simulation model that is experimentally validated. By comparing the simulated flow rates with the experimentally obtained flow rates, and the simulated droplet diameters with the experimentally obtained droplet diameters, it was found that the errors are all less than 10

%

which demonstrates this numerical simulation model is adequately validated by experiment. Thus, instead of carrying out expensive experiments, this simulation model can be used for predicting the volumetric flow rates for different prescribed orifice geometries. Furthermore, this paper also simulates the effects of viscosity and surface tension on the flow rate, where either viscosity or surface tension increases, the flow rate will decrease.
X-ray spectrometry for calculating conversion coefficients from air kerma to operational quantities in radiation protection
Authors: Plagnard Johann , Lefèvre Jérémie
Published: July 2024

This study explores the conversion coefficients from air kerma to operational quantities for radiation protection, using x-ray spectrometry for the narrow-beam qualities below 300 keV as defined by ISO 4037-1. By employing custom spectral correction algorithms combined with modern cadmium telluride (CdTe) semiconductor detectors, we effectively corrected spectral distortions caused by detection processes, ensuring more reliable measurements. These measurements are crucial for meeting radiation protection standards. The study also analyses the sources of uncertainty associated with the determination of conversion coefficients, thereby providing improved accuracy and reproducibility in photon dosimetry.
Study on the interaction mechanism of laser-generated Rayleigh waves and subsurface inclined cracks
Authors: Wang Chuanyong , Zhang Fumin , Chen Yuanliu , Wang Wen , Wang Yun , Lu Keqing , Ding Yuanping , Shen Yinliang , Ju Bing-Feng
Published: July 2024

In this paper, the finite element method was used to study the reflected and transmitted waves of laser-generated Rayleigh waves from subsurface inclined cracks, the propagation paths and mode conversion mechanisms of different characteristic waves are determined. The Rayleigh wave will interact with the crack top tip and propagate back and forth along the crack surface, and be converted to shear waves at the crack top tip. The shear waves will mode-convert to Rayleigh waves at the free surface when the incidence angle of the shear wave is larger than 60°. Moreover, for the Rayleigh wave interacting with the crack bottom tip, when the crack inclined angle is less than 60°, some Rayleigh waves will travel along the crack surface to the crack top tip. When the crack inclination angle is greater than 60°, in addition to the Rayleigh waves propagating upwards along the crack surface, some Rayleigh waves convert to shear waves at the crack bottom tip and then incident on the free surface of the workpiece. Experiments were carried out to validate some of the Rayleigh wave propagation paths. The experimental results matched the theoretical arrival time well, thus verifying the reliability of the analytical wave path. The results are helpful for the quantitative detection of subsurface inclined cracks using laser ultrasonic techniques.
Machine learning classification of permeable conducting spheres in air and seawater using electromagnetic pulses
Authors: Thomas Ryan , Salmon Brian , Holloway Damien , Olivier Jan
Published: July 2024

This paper presents machine learning classification on simulated data of permeable conducting spheres in air and seawater irradiated by low frequency electromagnetic pulses. Classification accuracy greater than 90% was achieved. The simulated data were generated using an analytical model of a magnetic dipole in air and seawater placed 1.5–3.5 m above the center of the sphere in 50 cm increments. The spheres had radii of 40 cm and 50 cm and were of permeable materials, such as steel, and non-permeable materials, such as aluminum. A series RL circuit was analytically modeled as the transmitter coil, and an RLC circuit as the receiver coil. Additive white Gaussian noise was added to the simulated data to test the robustness of the machine learning algorithms to noise. Multiple machine learning algorithms were used for classification including a perceptron and multiclass logistic regression, which are linear models, and a neural network, 1D convolutional neural network (CNN), and 2D CNN, which are nonlinear models. Feature maps are plotted for the CNNs and provide explainability of the salient parts of the time signature and spectrogram data used for classification. The pulses investigated, which expand the literature, include a two-sided decaying exponential, Heaviside step-off, triangular, Gaussian, rectangular, modulated Gaussian, raised cosine, and rectangular down-chirp. Propagation effects, including dispersion and frequency dependent attenuation, are encapsulated by the analytical model, which was verified using finite element modeling. The results in this paper show that machine learning methods are a viable alternative to inversion of electromagnetic induction (EMI) data for metallic sphere classification, with the advantage of real-time classification without the use of a physics-based model. The nonlinear machine learning algorithms used in this work were able to accurately classify metallic spheres in seawater even with significant pulse distortion caused by dispersion and frequency dependent attenuation. This paper presents the first effort towards the use of machine learning to classify metallic objects in seawater based on EMI sensing.
Phonon transport in vacancy induced defective stanene/hBN van der Waals heterostructure
Authors: Hassan Mehady , Das Priom , Paul Plabon , Morshed AKM Monjur , Paul Titan C
Published: July 2024

In this study, Non-Equilibrium Molecular Dynamics (NEMD) simulation is employed to investigate the phonon thermal conductivity (PTC) of Sn/hBN van der Waals heterostructures with different vacancy-induced defects. We deliberately introduce three types of vacancies in Sn/hBN bilayer point vacancies, bivacancies, and edge vacancies at various concentrations ranging from 0.25% to 2%, to examine their effects on PTC across temperatures from 100 K to 600 K. The key findings of our work are (i) PTC declines monotonically with increasing vacancy concentration for all types of vacancies, with a maximum reduction of ∼62% observed at room temperature compared to its pristine form. (ii) The position of defects has an impact on PTC, with a larger decrease observed when defects are present in the hBN layer and a smaller decrease when defects are in the Sn layer. (iii) The type of vacancy also influences PTC, with point vacancies causing the most substantial reduction, followed by bivacancies, and edge vacancies having the least effect. A 2% defect concentration results in a ∼62% decrease in PTC for point vacancies, ∼51% for bivacancies, and ∼32% for edge vacancies. (iv) Finally, our results indicate that for a given defect concentration, PTC decreases as temperature increases. The impact of temperature on thermal conductivity is less pronounced compared to the effect of vacancies for the defective Sn/hBN bilayer. The presence of vacancies and elevated temperatures enhance phonon-defect and phonon–phonon scattering, leading to changes in the phonon density of states (PDOS) profile and the distribution of phonons across different frequencies of Sn/hBN bilayer, thus affecting its thermal conductivity. This work offers new insights into the thermal behavior of vacancy-filled Sn/hBN heterostructures, suggesting potential pathways for modulating thermal conductivity in bilayer van der Waals heterostructures for applications in thermoelectric, optoelectronics, and nanoelectronics in future.
Effective estimates of ergodic quantities illustrated on the Bolyai-Rényi map
Authors: Pollicott Mark , Slipantschuk Julia
Published: July 2024

We present a practical and effective method for rigorously estimating quantities associated to top eigenvalues of transfer operators to very high precision. The method combines explicit error bounds of the Lagrange-Chebyshev approximation with an established min-max method. We illustrate its applicability by significantly improving rigorous estimates on various ergodic quantities associated to the Bolyai–Rényi map.
Fast Monte Carlo dose calculation in proton therapy
Authors: Holmes Jason , Feng Hongying , Zhang Lian , Fix Michael K , Jiang Steve B , Liu Wei
Published: July 2024

This article examines the critical role of fast Monte Carlo (MC) dose calculations in advancing proton therapy techniques, particularly in the context of increasing treatment customization and precision. As adaptive radiotherapy and other patient-specific approaches evolve, the need for accurate and precise dose calculations, essential for techniques like proton-based stereotactic radiosurgery, becomes more prominent. These calculations, however, are time-intensive, with the treatment planning/optimization process constrained by the achievable speed of dose computations. Thus, enhancing the speed of MC methods is vital, as it not only facilitates the implementation of novel treatment modalities but also leads to more optimal treatment plans. Today, the state-of-the-art in MC dose calculation speeds is 106–107 protons per second. This review highlights the latest advancements in fast MC dose calculations that have led to such speeds, including emerging artificial intelligence-based techniques, and discusses their application in both current and emerging proton therapy strategies.
Generation of high-density plasma via transparent electrode in capacitively coupled plasma
Authors: Moon Ho-Jun , Jung Jiwon , Park Junyoung , Chung Chin-Wook
Published: July 2024

The effect of transparent capacitively coupled plasmas (TCCP) is investigated by using a transparent ITO electrode instead of the metal electrode of capacitively coupled plasmas (CCP). To compare the CCP and the TCCP, the CCP is made by coating the powered electrode with metal and the TCCP is made by coating the powered electrode with Indium Tin Oxide (ITO) on the quartz window. To compare the properties of electrodes based on ITO electrodes and metal electrodes in the same size reactor, electrode voltage, electron temperature and electron density were measured at various applied RF powers and pressures at 13.56 MHz. The electron temperature decreases overall with pressure, regardless of the electrode type. We observed that the total voltage between the powered electrode and ground is about two times higher for the TCCP than for the CCP. In addition, the electron density of the TCCP increases significantly by about two times that of the CCP. In this TCCP, the voltage applied to the sheath is calculated based on the fact that the increase in electron density is related to the voltage applied to the sheath. The calculated voltages applied to each sheath of the CCP and the TCCP agree well with our experimental results. In addition, From the calculated total power absorption per unit area, it is found that the total power absorption per unit area is significantly higher in the TCCP than in the CCP.
Development of finger movement assistive gloves with pneumatic fabric actuators
Authors: Chung Jiwon , Yoon Jeong Eun , Kim Minseo , Shin Dongjun , Koo Sumin
Published: July 2024

We developed flexible, lightweight, and washable gloves with actuators to assist finger movements and improve ease of wearing. Performance and wearability were measured using standardized tests, triangulation of bending angles, electromyography (EMG), and grip strength. User satisfaction was measured using a survey. EMG sensors were attached to the flexor digitorum superficialis and extensor digitorum communis to capture movement data for grasping and releasing, lifting and putting down, and opening and closing an object with (a) gloves and an actuator, (b) gloves and no actuator, and (c) no gloves. The actuator-equipped glove weighed 31.4 g—lighter than in any earlier studies. In situation (a), the average EMG values for the four participants decreased, ranging from −2.06% to −44.1%, confirming the superior performance of the gloves. Survey results revealed high levels of user satisfaction. Our study offers insights into the development of rehabilitation robotic gloves that assist muscle movements and are easy to wear.
A Diamond Ring in X-Ray: Investigating the Diffuse Emission of Supernova Remnant G28.8+1.5
Authors: Zhang Kaiyue
Published: July 2024

Supernova remnants are products of supernova explosions, which are usually observed in the X-ray band. However, the diffuse emission from the galactic supernova remnant G28.8+1.5 has been overlooked following initial searches for pulsars and pulsar wind nebulae. This paper presents background-subtracted imaging and spatial-resolved spectral analyses using archival XMM-Newton data to reveal unprecedented details of the diffuse emission, providing updated estimates of distance and age. For the first time, an iron overabundance is revealed and the progenitor is suggested to be 9–15 M
⊙. These findings refine our understanding of G28.8+1.5 and contribute to a broader comprehension of the Galactic supernova remnant family.
Emergence of multivariate climate change signals
Authors: King Andrew D , Harrington Luke J , Hawkins Ed , Paik Seungmok , Lieber Ruby , Min Seung-Ki , Borowiak Alexander R
Published: July 2024

The emergence of a climate change signal relative to background variability is a useful metric for understanding local changes and their consequences. Studies have identified emergent signals of climate change, particularly in temperature-based indices with weaker signals found for precipitation metrics. In this study, we adapt climate analogue methods to examine multivariate climate change emergence over the historical period. We use seasonal temperature and precipitation observations and apply a sigma dissimilarity method to demonstrate that large local climate changes may already be identified, particularly in low-latitude regions. The multivariate methodology brings forward the time of emergence by several decades in many areas relative to analysing temperature in isolation. We observed particularly large departures from an early-20th century climate in years when the global warming signal is compounded by an El Niño-influence. The latitudinal dependence in the emergent climate change signal means that lower-income nations have experienced earlier and stronger emergent climate change signals than the wealthiest regions. Analysis based on temperature and precipitation extreme indices finds weaker signals and less evidence of emergence but is hampered by lack of long-running observations in equatorial areas. The framework developed here may be extended to attribution and projections analyses.
Mega project impact on urban growth and ecosystem service
Authors: Zuhra Fatema Tuz , Upaul Sharfan
Published: July 2024

In an effort to forecast and estimate the value of ecosystem services (ESVs) and land use and land cover changes (LULC), recent global events and research have centered on the evaluation of LULC. This study evaluates the effectiveness of an integrated approach using multi-layer perceptron-Markov chain analysis (MLP-MCA) and remote sensing data for monitoring land use and land cover (LULC) changes. The study area comprises the three Bangladeshi upazilas that the Padma Bridge connects: Shariatpur, Louhajang, and Janjira. The Ecosystem Services Valuation Database (ESVD) was used to evaluate the impacts of changes in land use and land cover (LULC) on Ecosystem Service Values (ESVs). The LULC of the study area was estimated for the years 2000, 2010, and 2020, and the forecast period for urban development was 2030 and 2040. Additionally, the monetary value of ecosystem services was evaluated across the time. As per the LULC change analysis, there is a projected 4.35% growth in the built-up area from 2000 to 2020. After the bridge is constructed, the built-up area is projected to increase by 7% in 2030 and 14% in 2040, according to the forecast. The exponential expansion of developed land has a paradoxical effect on the value of ecosystem services. From 2020 to 2040, it is expected that the ESVs for provision, regulation, culture, and support will experience a reduction of approximately 213.24 million USD/ha. Even if the establishment of a bridge results in economic stability and investment attraction for the nation, unforeseen ecosystem service losses cannot contribute to long-term, sustainable development. This study, by establishing a correlation between urban area expansion and the deterioration of ecosystem services, can serve as a standard and basis for guiding management decisions.
Polarization dynamics: a study of individuals shifting between political communities on social media
Authors: Albanese Federico , Feuerstein Esteban , Balenzuela Pablo
Published: July 2024

Individuals engaging on social media often tend to establish online communities where interactions predominantly occur among like-minded peers. While considerable efforts have been devoted to studying and delineating these communities, there has been limited attention directed towards individuals who diverge from these patterns. In this study, we examine the community structure of re-post networks within the context of a polarized political environment at two different times. We specifically identify individuals who consistently switch between opposing communities and analyze the key features that distinguish them. Our investigation focuses on two crucial aspects of these users: the topological properties of their interactions and the political bias in the content of their posts. Our analysis is based on a dataset comprising 2 million tweets related to US President Donald Trump, coupled with data from over 100 000 individual user accounts spanning the 2020 US presidential election year. Our findings indicate that individuals who switch communities exhibit disparities compared to those who remain within the same communities, both in terms of the topological aspects of their interaction patterns (pagerank, degree, betweenness centrality.) and in the sentiment bias of their content towards Donald Trump.
Exploring the space of graphs with fixed discrete curvatures
Authors: Roost Michelle , Devriendt Karel , Zucal Giulio , Jost Jürgen
Published: July 2024

Discrete curvatures are quantities associated to the nodes and edges of a graph that reflect the local geometry around them. These curvatures have a rich mathematical theory and they have recently found success as a tool to analyze networks across a wide range of domains. In this work, we consider the problem of constructing graphs with a prescribed set of discrete edge curvatures, and explore the space of such graphs. We address this problem in two ways: first, we develop an evolutionary algorithm to sample graphs with discrete curvatures close to a given set. We use this algorithm to explore how other network statistics vary when constrained by the discrete curvatures in the network. Second, we solve the exact reconstruction problem for the specific case of Forman–Ricci curvature. By leveraging the theory of Markov bases, we obtain a finite set of rewiring moves that connects the space of all graphs with a fixed discrete curvature.
Benchmarking machine learning interatomic potentials via phonon anharmonicity
Authors: Bandi Sasaank , Jiang Chao , Marianetti Chris A
Published: July 2024

Machine learning approaches have recently emerged as powerful tools to probe structure-property relationships in crystals and molecules. Specifically, machine learning interatomic potentials (MLIPs) can accurately reproduce first-principles data at a cost similar to that of conventional interatomic potential approaches. While MLIPs have been extensively tested across various classes of materials and molecules, a clear characterization of the anharmonic terms encoded in the MLIPs is lacking. Here, we benchmark popular MLIPs using the anharmonic vibrational Hamiltonian of ThO2 in the fluorite crystal structure, which was constructed from density functional theory (DFT) using our highly accurate and efficient irreducible derivative methods. The anharmonic Hamiltonian was used to generate molecular dynamics (MD) trajectories, which were used to train three classes of MLIPs: Gaussian approximation potentials, artificial neural networks (ANN), and graph neural networks (GNN). The results were assessed by directly comparing phonons and their interactions, as well as phonon linewidths, phonon lineshifts, and thermal conductivity. The models were also trained on a DFT MD dataset, demonstrating good agreement up to fifth-order for the ANN and GNN. Our analysis demonstrates that MLIPs have great potential for accurately characterizing anharmonicity in materials systems at a fraction of the cost of conventional first principles-based approaches.
Application of deep learning-based fuzzy systems to analyze the overall risk of mortality in glioblastoma multiforme
Authors: Yang Cheng-Hong , Cheung Tin-Ho , Chuang Li-Yeh
Published: July 2024

Glioblastoma multiforme (GBM) is the most aggressive brain cancer in adults, with 3.2–3.4 cases per 100 thousand. In the US, brain cancer does not rank in the top 10 causes of death, but it remains in the top 15. Therefore, this research proposes a fuzzy-based GRUCoxPH model to identify missense variants associated with a high risk of all-cause mortality in GBM. The study combines various models, including fuzzy logic, gated recurrent units (GRUs), and Cox proportional hazards regression (CoxPh), to identify potential risk factors. The dataset is derived from TCGA-GBM clinicopathological information and mutations to create four risk score models: GRU, CoxPH, GRUCoxPHAddition, and GRUCoxPHMultiplication, analyzing nine risk factors of the dataset. The Fuzzy-based GRUCoxPH model achieves an average accuracy of 87.64%, outperforming other models. This model demonstrates its ability to classify and identify missense variants associated with mortality in GBM, potentially advancing cancer research.
Usefulness of point of care ultrasound in older adults: a multicentre study across different geriatric care settings in Spain and the United Kingdom
Authors: Reinoso-Párraga Paola Pastora , González-Montalvo Juan Ignacio , Menéndez-Colino Rocío , Perkisas Stany , Rivera-Deras Ivón , Garmendia-Prieto Blanca , Arain Salman Javed , Tung-Chen Yale , Vilches-Moraga Arturo
Published: July 2024

Background

Point of care ultrasound (POCUS) is an imaging technique performed bedside. To date, few published studies have reported the usefulness of multiorgan POCUS in Geriatrics. The objective of this study was to describe the utility of multiorgan POCUS in the care of older adults admitted to geriatric care settings.

Methodology

Observational retrospective study of patients admitted to geriatric settings in Spain and UK. Multiorgan POCUS was performed when there was a specific clinical suspicion or unexplained torpid clinical course despite physical examination and complementary tests. A geriatrician with a certificate degree in comprehensive ultrasound and long-standing experience in POCUS carried out POCUS. All patients underwent multiorgan POCUS in a cephalo-caudal manner.

Results

Out of 368 patients admitted to geriatric units, 29% met the inclusion criteria. Average age was 85.9 years (SD ± 6.1). POCUS identified 235 clinically significant findings (2.2 per patient). Findings were classified as 37.9% confirmed diagnosis, 16.6% ruled out diagnosis, 14.9% unsuspected relevant diagnoses and 30.6% clinical follow-ups. POCUS findings led to changes in pharmacological and non-pharmacological treatment in 66.3 and 69.2% respectively, resulted in completion or avoidance of invasive procedures in 17.8 and 15.9%, respectively, facilitating early referrals to other specialities in 14.9% and avoiding transfers in 25.2% of patients.

Conclusion

Multiorgan POCUS is a tool that aids in the assessment and treatment of patients receiving care in geriatrics units. These results show the usefulness of POCUS in the management of older adults and suggest its inclusion in any curriculum of Geriatric Medicine speciality training.
HbA2 levels in children with β-thalassemia trait associated with iron deficiency: A perspective for pediatricians
Authors: Değermenci Şeyda , Aslan Deniz
Published: July 2024

Objectives

A critical factor in β-thalassemia trait screening is a hemoglobin A2 (HbA2) level of 3.5% or higher. In children with iron deficiency, HbA2 levels decrease, and diagnosis may be missed. Studies with adult carriers have yielded conflicting results on this issue. The effectiveness of HbA2–based thalassemia screening in carrier children with iron deficiency has not been studied before.

Methods

In this study, among 213 children with β-thalassemia trait, those with iron deficiency were determined based on ferritin value (<15 ng/mL), and their HbA2 levels were examined. We compared HbA2 levels of iron-deficient and iron-sufficient carriers and examined the correlation between low HbA2 levels and ferritin level. Because ferritin is an acute-phase reactant, similar evaluations were made by using transferrin saturation as the criterion for iron deficiency.

Results

The median HbA2 value of iron-deficient carrier children was 4.1% and within the diagnostic range (≥3.5%) in the majority of children. Median HbA2 levels in iron-deficient carriers differed from levels in iron-sufficient carriers (4.1% vs 4.9%, P < .007). No correlation was present between low HbA2 levels and ferritin levels (0.226). Furthermore, among children without iron deficiency, there were individuals with low HbA2 levels (26.9%). Similar results were obtained when transferrin saturation was used.

Conclusions

Hemoglobin A2 can be used as a screening test in children with β-thalassemia trait, despite accompanying iron deficiency. Low HbA2 levels in these children may be the result of underlying thalassemia mutation, not the result of accompanying iron deficiency. Therefore, in suspected cases of β-thalassemia trait, evaluation should continue, regardless of iron status or treatment.
Invited commentary: influence of incomplete death information on cumulative risk estimates
Authors: Lok Judith J
Published: July 2024

Censoring at death is the only feasible option if death is not recorded and individuals who died simply no longer contribute visits, such as in the setting of Barberio et al (Am J Epidemiol. 2024;193(9):1281-1290) before they acquired access to mortality information. Censoring at death is known to lead to biased estimates of the probability of the event of interest before time $t$. Barberio et al showed through simulations that this bias increases with increasing mortality. However, when analyzing claims data it is often important to not exclude individuals with shorter life expectancies: An important strength of observational studies is that they allow estimation of treatment effects in more varied populations than are typically included in randomized clinical trials. In this commentary, I derive an analytical expression for the bias and provide 2 upper bounds for the bias. The bounds inform the usefulness of obtaining mortality information. If the probability of death before the event is known to be small, wider CIs can be created using the first bound on the bias; an algorithm is provided. If the bias is large, obtaining mortality information is important. Barberio et al show that obtaining mortality information can be essential in practice.

This article is part of a Special Collection on Pharmacoepidemiology.