bluuebunny/crossref_metadata_2025 huggingface dataset:
Failure of Universal 2 Wrist Joint Replacements: A Retrieval Study
Authors: Joyce Thomas J. , Kandemir Göksu , Zreik Nasri H. , Talwalkar Sumedh , Trail Ian
Published: October 2024

Background The Universal 2 total wrist arthroplasty was one of the most common wrist replacements, but long-term results were disappointing, due to substantial damage to the polyethylene component and, in some cases, metallosis. The purpose of this research was to investigate the underlying reasons for this polyethylene damage.

Methods From a single clinical center, retrieval analysis was undertaken on six Universal 2 wrists and two additional polyethylene components. All components were analyzed at the macroscale and dimensional measurements of polyethylene components were undertaken. These were compared against known component orientation in vivo to identify areas of greatest material loss.

Results Of 62 Universal 2 wrists implanted, there was a tendency for smaller implants to be revised more frequently. Of the six explanted wrists, material loss was always noticeable on the ulnar side, and to a lesser extent in the dorsal direction. Five of eight polyethylene components had failed at the base of the ulnar-side blind hole. Smaller implants tended to have less thickness at the base of the blind holes, thus explaining the failure of smaller sizes. Discoloration and surface fatigue of explants indicated oxidation of components. Average time in vivo for the explants was 13.8 years which indicates the slow nature of polyethylene oxidation. All were revised due to loosening. All were implanted in rheumatoid patients with a mean age at surgery of 56.1 years. Three of the six Universal 2 wrists, all sized Extra Small, showed severe wear of the titanium alloy carpal component.

Conclusion Failure of the polyethylene components was due to a combination of inappropriate sterilization technique plus a design issue where polyethylene was thinnest on the smallest size components. Continued surveillance of patients implanted with Universal 2 wrists is recommended.
International, Multi-Institutional Evaluation of Practice Patterns and Outcomes for Recurrent and Metastatic Sinonasal Undifferentiated Carcinoma
Authors: Saraswathula Anirudh , Ullah Mohammed N. , Liu Jacklyn , Takahashi Yoko , Mahajan Arushi , Battocchio Simonetta , Bossi Paolo , Castelnuovo Paolo , Facco Carla , Ferrari Marco , Carnell Dawn , Forster Martin D. , Franchi Alessandro , Jay Amrita , Lombardi Davide , Lund Valerie J. , Mattavelli Davide , Nicolai Piero , Rampinelli Vittorio , Sessa Fausto , Su Shirley Y. , Turri-Zanoni Mario , Ardighieri Laura , McKean Erin , Lechner Matt , Hanna Ehab , London Nyall R.
Published: October 2024

Objectives The aims of this study were to analyze the clinical characteristics of patients with recurrent and metastatic sinonasal undifferentiated carcinoma (SNUC) and evaluate the current treatment strategies to help guide future management.

Design This is a retrospective cohort study.

Setting The study was conducted at six international tertiary treatment centers.

Participants Patients with documented diagnoses of recurrent or metastatic SNUC since 1983 were included in the study.

Main Outcome Measures Patient demographics and clinical characteristics were collected. Primary outcome measures included disease-specific survival (DSS), overall survival (OS), and time to recurrence (TTR) following initial treatment. Further univariable and multivariable analyses were performed to assess for prognostic factors.

Results A total of 97 patients with a mean (standard deviation [SD]) age of 52.4 (15.6) were identified, 15 of whom presented with metastatic SNUC and 90 of whom developed recurrence. Management in both populations was widely variable. For patients with metastatic disease, the 1-year DSS probability was 33.3% (95% confidence interval [CI], 10.8–100%). For patients with recurrent SNUC, the 1- and 5-year DSS probabilities were 45.7% (95% CI, 31.9–65.6%) and 8.6% (95% CI, 2.9–25.3%), respectively. The median (interquartile range [IQR]) TTR was 8 months (3–18.5 months). Multivariable analyses revealed a significant association between orbital involvement on initial presentation and TTR (hazard ratio [HR] = 3.28; 95% CI, 1.45–7.42; p = 0.004).

Conclusions To our knowledge, this is the first study addressing metastatic and recurrent SNUC based on a large patient cohort. Orbital extension of the primary SNUC may predict a higher probability of recurrence following treatment, suggesting the possible utility of a more aggressive treatment in this subgroup of patients. A heterogenous patient population and wide variability in management emphasize the challenges in standardizing care; however, dismal survival rates demonstrate the necessity for further evaluation of current approaches to improve evidence-based recommendations.
Exploring corporate reputation and crisis communication
Authors: Nuortimo Kalle , Harkonen Janne , Breznik Kristijan
Published: October 2024

Corporate reputation, the collective perception of company attractiveness towards stakeholders, impacts business outcomes, while effective communication strategies play a critical role in shaping and maintaining the reputation. The role of communication is highlighted during crises, crisis communication being a strategic approach to managing and mitigating the impact of unexpected or adverse events on the reputation, operations, and stakeholders. These concepts are deeply interrelated with interactive marketing. This study explores the dynamics of corporate reputation and crisis communication during a recent global crisis by combining a literature review, opinion mining, and classification analysis. This is because stakeholders rely on various information sources and engage in online discussions, which can impact the reputation, and pose new challenges. The opinion mining analysis draws from the media communication of selected stock-listed companies during a crisis. The key findings shed light on the dynamics of corporate reputation and crisis communication and the impacts on interactive marketing. Critical components of crisis communication are identified to include monitoring, tactics of responding, and response management. Linkages between these, crisis communication theories, and corporate reputation are synthesised. Indications are provided on how the crisis can affect the corporate reputation and the significance of the speed of preventive communication measures.
Topology-optimized 2D silicon–air phononic crystal slabs for enhancing quality factor of laterally vibrating resonators
Authors: Xie Zihao , Fu Yongqing , Xie Jin
Published: October 2024

Two-dimensional phononic crystal (PnC) slabs have shown advantages in enhancing the quality factors Q of piezoelectric laterally vibrating resonators (LVRs) through topology optimization. However, the narrow geometries of most topology-optimized silicon–air 2D PnC slabs face significant fabrication challenges owing to restricted etching precision, and the anisotropic nature of silicon is frequently overlooked. To address these issues, this study employs the finite element method with appropriate discretization numbers and the genetic algorithm to optimize the structures and geometries of 2D silicon–air PnC slabs. The optimized square-lattice PnC slabs, featuring a rounded-cross structure oriented along the ⟨110⟩ directions of silicon, achieve an impressive relative bandgap (RBG) width of 82.2% for in-plane modes. When further tilted by 15° from the ⟨100⟩ directions within the (001) plane, the optimal RBG width is expanded to 91.4%. We fabricate and characterize thin-film piezoelectric-on-silicon LVRs, with or without optimized 2D PnC slabs. The presence of PnC slabs around anchors increases the series and parallel quality factors Qs and Qp from 2240 to 7118 and from 2237 to 7501, respectively, with the PnC slabs oriented along the ⟨110⟩ directions of silicon.
Wireless transmission of audio signals and temperature data using an optoelectronic system
Authors: Sabory-García R. , García-Delgado L. A. , Noriega J. R. , Acosta-Enríquez M. C. , Vera-Marquina A. , Leal-Cruz A. L. , Zaldívar-Huerta I. E. , García-Juárez A.
Published: October 2024

This work presents an optoelectronic instrument designed for wireless visible light communication (WVLC) systems, operating within a wavelength range of 380–750 nm and compatible with standard radio frequency (RF) communication. The instrument encompasses two distinct architectures. The first enables the transmission and reception of RF-processed audio signals through a three-stage process involving RF signal transmission via Bluetooth, signal multiplexing using acousto-optic modulation, a sinusoidal grating, a PIN photodetector array, and final audio playback. The second architecture focuses on the wireless transmission and reception of temperature data, utilizing a similar three-stage approach that includes temperature data measurements with an LM35 sensor, signal processing with Arduino UNO microcontrollers, and information transmission via Bluetooth. Experimental results for both architectures validate the effectiveness of this optoelectronic instrument, demonstrating its capability to integrate RF and WVLC technologies.
Toward utilizing scanning gate microscopy as a high-resolution probe of valley splitting in Si/SiGe heterostructures
Authors: Cakar Efe , Ercan H. Ekmel , Fuchs Gordian , Denisov Artem O. , Anderson Christopher R. , Gyure Mark F. , Petta Jason R.
Published: October 2024

A detailed understanding of the material properties that affect the splitting between the two low-lying valley states in Si/SiGe heterostructures will be increasingly important as the number of spin qubits is increased. Scanning gate microscopy has been proposed as a method to measure the spatial variation of the valley splitting as a tip-induced dot is moved around in the plane of the Si quantum well. We develop a simulation using an electrostatic model of the scanning gate microscope tip and the overlapping gate structure combined with an approximate solution to the three-dimensional Schrödinger–Poisson equation in the device stack. Using this simulation, we show that a tip-induced quantum dot formed near the source and drain electrodes can be adiabatically moved to a region far from the gate electrodes. We argue that by spatially translating the tip-induced dot across a defect in the Si/SiGe interface, changes in valley splitting can be detected.
An insight into the solitonic features of the nonlinear generalized higher-order Schrödinger equation using the solver method
Authors: Alhazmi Hadil , Bajri Sanaa A. , El-Shewy E. K. , Abdelrahman Mahmoud A. E.
Published: October 2024

For many nonlinear applications described by the dynamics of nonlinear Schrödinger equation with higher-order terms (HONLSE) such as nonlinear optics, space plasma physics molecular biology, astrophysics, quantum mechanics, superfluid, fluid mechanics, and fiber optics communications, a unique closed-form solution have been obtained using energy equation. In addition, some new solitary solutions HONLSE have been obtained via the unified solver method. The resultant solutions behave as breathers, super solitons, envelope breathers, blow up, localized super waves, periodical super shock, train super solitons, and shock structures. The modulations of Kerr nonlinear, chromatic dispersive, and wave packet drift parameters on the wave characteristics of the obtained solutions have been investigated. It was reported that the model parameters affect the amplitude, steepness, and width of the resultant structures. The provided solution can be used as a box solver for a variety of natural science systems described by distinct nonlinear equations.
Field trial of stable radio frequency transfer system in 200 km metropolitan optical fiber link
Authors: Liu Chenxia , Wang Hanyue , Song Ge , Gao Hao , Cheng Jiahui , Liu Tao , Yu Song
Published: October 2024

In this paper, we demonstrate stable radio frequency (RF) transfer via metropolitan optical fiber link in the Beijing area. The phase variation of the RF signal is compensated by a phase conjugation method incorporating two high-performance phase-locked loops. The wavelength conversion module extends the transmission length to 200 km with only two parallel 50 km dark optical fibers available. We optimize the configuration of dispersion compensation and optical amplification due to the high loss (0.31 dB/km) of the optical fiber link. At the same time, comparative experiments verify the short-term instability limitation that arises from the group velocity dispersion of the optical fiber link. The measured standard Allan deviation of the 2.4 GHz RF transmission system with dispersion compensation is 4.5 × 10−14/1 and 2.6 × 10−17/20 000 s, which is superior to that of the reference rubidium clock. The short-term instability of the system is deteriorated to 2.5 × 10−13/1 s without dispersion compensation.
Adsorption of polyelectrolytes in the presence of varying dielectric discontinuity between solution and substrate
Authors: Vahid Hossein , Scacchi Alberto , Sammalkorpi Maria , Ala-Nissila Tapio
Published: October 2024

We examine the interactions between polyelectrolytes (PEs) and uncharged substrates under conditions corresponding to a dielectric discontinuity between the aqueous solution and the substrate. To this end, we vary the relevant system characteristics, in particular the substrate dielectric constant ɛs under different salt conditions. We employ coarse-grained molecular dynamics simulations with rodlike PEs in salt solutions with explicit ions and implicit water solvent with dielectric constant ɛw = 80. As expected, at low salt concentrations, PEs are repelled from the substrates with ɛs < ɛw but are attracted to substrates with a high dielectric constant due to image charges. This attraction considerably weakens for high salt and multivalent counterions due to enhanced screening. Furthermore, for monovalent salt, screening enhances adsorption for weakly charged PEs, but weakens it for strongly charged ones. Meanwhile, multivalent counterions have little effect on weakly charged PEs, but prevent adsorption of highly charged PEs, even at low salt concentrations. We also find that correlation-induced charge inversion of a PE is enhanced close to the low dielectric constant substrates, but suppressed when the dielectric constant is high. To explore the possibility of a PE monolayer formation, we examine the interaction of a pair of like-charged PEs aligned parallel to a high dielectric constant substrate with ɛs = 8000. Our main conclusion is that monolayer formation is possible only for weakly charged PEs at high salt concentrations of both monovalent and multivalent counterions. Finally, we also consider the energetics of a PE approaching the substrate perpendicular to it, in analogy to polymer translocation. Our results highlight the complex interplay between electrostatic and steric interactions and contribute to a deeper understanding of PE–substrate interactions and adsorption at substrate interfaces with varying dielectric discontinuities from solution, ubiquitous in biointerfaces, PE coating applications, and designing adsorption setups.
GaAs-based photonic integrated circuit platform enabling monolithic ring-resonator-coupled lasers
Authors: Koester Jan-Philipp , Wenzel Hans , Fricke Jörg , Reggentin Matthias , Della Casa Pietro , Sammeta Poojitha , Brox Olaf , Ekterai Michael , Kohlbrenner Mario , Renkewitz Andreas , Zink Christof , Tenzler Thomas , Boschker Jos , Weyers Markus , Knigge Andrea
Published: October 2024

This paper reports on a monolithically integrated gallium arsenide (GaAs)-based photonic integrated circuit platform for wavelengths around 1064 nm. Enabled by spatially selective quantum well removal and two-step epitaxial growth, it supports on-chip gain as well as passive waveguides. In addition, shallow- and deep-etched waveguides are realized. The former result in waveguide losses of less than 2 dB/cm, while the latter enable compact integrated waveguide components. To demonstrate the performance of the platform, racetrack ring resonators based on deep-etched Euler bends and shallow-etched directional couplers are realized, achieving high intrinsic quality factors of 2.6 × 105 and 3.2 × 105 for the fundamental TE and TM mode, respectively. To demonstrate the use of these resonators, ring-resonator-coupled lasers are fabricated, resulting in one-sided output powers of up to 14 mW and single-mode operation with 40 dB side-mode suppression. The successful integration of ring resonators on a GaAs-based active/passive photonic integrated circuit platform paves the way for the realization of fully monolithic, widely tunable, and narrow linewidth ring-resonator-coupled laser sources.
High-speed flows in the plasma accelerator channel for the regime of electron current-transport on coaxial electrodes
Authors: Kozlov Andrei N.
Published: October 2024

Analytical model of high-speed flows has been developed for the channel of quasi-stationary plasma accelerator used to create powerful electric jet plasma engine of new generation. The model of two-dimensional axisymmetric flows is based on the stationary equations of two-fluid magnetohydrodynamics for the ideal plasma and the smoothly varying channel approximation. The new approach to organizing flows using non-equipotential electrodes is associated with the electron current-transport regime, which ensures slipping of the heavy ion component of the plasma along anode and cathode. As a result of studying transonic flows in the profiled channel, the potential distributions along non-equipotential electrodes, as well as the integral characteristics of the flow, including mass flux and thrust, were determined.
Energy-harvesting behavior and configuration effect of two semi-active flapping foils
Authors: Zheng Min , Hou Guoxiang , Huang Zhenwei
Published: October 2024

This study investigates the energy-harvesting behavior and configuration effects of two semi-active flapping foils through numerical simulations, considering both tandem and unaligned configurations, as well as the influence of Reynolds number and pitch amplitude. The tandem configuration shows the greatest efficiency improvement, maximizing the utilization of the upstream foil's wake. In contrast, the unaligned configuration allows the downstream foil to surpass the energy-harvesting efficiency of the upstream foil, which is advantageous for clustered systems. The phase difference impacts wake structures, with the downstream foil recapturing the wake, though its efficiency is limited by the lower wake speed compared to the incoming flow velocity. The Reynolds number effect does not appear to influence the peak efficiency ratio, suggesting that the efficiency relationship between the foils remains consistent across different Reynolds numbers, despite potential differences in the optimal phase difference. Furthermore, reducing the pitch amplitude of the upstream foil optimally enhances the efficiency of the downstream foil, a factor that has often been overlooked. Lowering the pitch amplitude increases the wake speed, providing the downstream foil with a larger energy utilization space. This study provides valuable insights into the configuration design of flapping turbines, with the optimal two-foil system achieving an impressive efficiency of up to 46.3%. In the unaligned configuration, the lower the pitch amplitude of the upstream foil, the higher the efficiency ratio, which can reach up to ∼1.8. With different pitch amplitudes, the efficiency ratio consistently exceeds 1, indicating that the downstream foil benefits from the wake of the upstream foil. Combining more foils might further enhance efficiency in the unaligned configuration, as the higher efficiency in the tandem configuration is due to the repeated utilization of the sweep area by the two-foil system.
Shock turbulent interaction during shock-wave/boundary layer interaction over double wedge
Authors: Pal Ribhu , Roy Arnab
Published: October 2024

In this present study, turbulent kinetic energy amplification/attenuation inside the separation bubble has been investigated during strong shock-wave/boundary layer interaction over a double wedge surface. The objective has been fulfilled by decomposing the turbulent kinetic energy production term Pk into its three constituent terms, of which the turbulence production due to mean flow deceleration Px plays the dominating role. The transmitted shock (TS) emanating from the triple point impinges on the boundary layer formed over the aft surface of the wedge and executes an upstream movement followed by a downstream one during a short initial transient. The upstream movement of transmitted shock and reflected shock (RS) imposes a strong adverse pressure gradient on the separation bubble. During this, Px is augmented due to a strong negative mean streamwise velocity gradient ∂ũ/∂x. Downstream movement of TS and RS reduces the adverse pressure gradient and leads to a less strongly negative mean velocity gradient ∂ũ/∂x, thereby diminishing Px.
QFlowS: Quantum simulator for fluid flows
Authors: Bharadwaj Sachin S.
Published: October 2024

Quantum computing presents a possible paradigm shift in computing, given its advantages in memory and speed. However, there is a growing need to demonstrate its utility in solving practical problems that are nonlinear, such as in fluid dynamics, which is the subject of this work. To facilitate this objective, it is essential to have a dedicated toolkit that enables the development, testing, and simulation of new quantum algorithms and flow problems, taken together. To this end, we present here a high performance, quantum computational simulation package called Quantum Flow Simulator (QFlowS), designed for computational fluid dynamics simulations. QFlowS is a versatile tool that can create and simulate quantum circuits using an in-built library of fundamental quantum gates and operations. We outline here all its functionalities with illustrations. Algorithms to solve flow problems can be built using the expanding list of the core functionalities of QFlowS with its hybrid quantum–classical type workflow. This is demonstrated here by solving an example, one-dimensional, diffusion flow problem. These simulations serve as a check on the algorithm's correctness as well as an ideal test-bed for making them more efficient and better suited for near-term quantum computers for addressing flow problems.
Relative permeability measurement and two-phase flow visualization in micromodels of vugular porous media
Authors: Fernández Escalante Jesús , Avendaño Jorge , S. Carvalho Márcio
Published: October 2024

Close to 50% of the world's oil and gas reserves are held in naturally fractured carbonate reservoirs. In addition to the presence of fractures, vugs at different scales and distributions are scattered throughout the porous matrix. These cavities cause fluid flow characteristics to significantly differ from those of conventional homogeneous pore structure reservoirs and bring the need to evaluate equivalent petrophysical properties of the heterogeneous medium. In this study, a microfluidic approach is used to determine water and oil relative permeability curves and phase distribution in two-dimensional micromodels of vugular porous media. Steady-state water–oil injection experiments were performed at different fractional flows, while monitoring the dynamics of the pressure drop and visualizing the fluid displacement at the pore scale. Live-image acquisition through fluorescence microscopy made it possible to examine the evolution of the saturation of water and oil phases. A direct comparison between the relative permeability curves of well-characterized vugular porous media and their porous matrix showed that the incorporation of vugs leads to (i) higher equivalent absolute permeability, especially with longer cavities and higher vug density, (ii) increased oil occupancy in the porous matrix, due to less efficient water invasion into the porous matrix, and (iii) higher relative permeability to water, which flows preferentially through the vugular space. These results are consistent with the oil-wet nature of micromodels, since the vugs offer less capillary resistance to the flow of the non-wetting phase.
Numerical investigation into the transition of electrohydrodynamic spraying modes and behaviors
Authors: Guo Yujie , Guan Yin , He Bin , Sha Yanxiu , Wang Mengduo , Hu Zouwei , Lei Yihang
Published: October 2024

Electrohydrodynamic (EHD) spraying is an interesting phenomenon where the liquid subjected to an electrical stress deforms into an electrified liquid drop, a thin liquid jet, or the so-called Taylor cone, which is also highly complicated owing to its various spraying modes and behaviors. Due to the lack of critical information such as the electric charge density and internal velocity profile, the underlying physics behind the transition of different EHD spraying modes are still not adequately understood. In light of this, we conducted a numerical investigation into the transition of EHD spraying modes and behaviors under the three most important operating parameters including electric voltage, nozzle height, and liquid flow rate. Four typical spraying modes, namely, dripping, cone-jet, multi-jet, and jetting, are observed. From the numerical results, we obtained the voltage distribution in the environment, electric charge density at the liquid–air interface, and velocity profile inside the liquid, which help us to comprehensively analyze and explicate the influences of these three parameters on the transition of spraying modes and behaviors. This eventually leads us to a spraying mode map showing the correlation between the spraying modes and the electric Bond number. To the best of our knowledge, this is the first numerical work focusing on the transition of EHD spraying mode, from which we intend to expand the knowledge of this interesting phenomenon.
Capturing non-equilibrium in hypersonic flows: Insights from a two-temperature model in polyatomic rarefied gases
Authors: Kumar Anil , Rana Anirudh Singh
Published: October 2024

The study utilizes a two-temperature model to analyze non-equilibrium in normal shocks within hypersonic flows in polyatomic rarefied gases. Derived from the extended second law of thermodynamics, this model separates translational and internal temperatures in polyatomic gases, providing a more accurate depiction of non-equilibrium gas flow compared to classical theories like the Navier–Stokes and Fourier (NSF) system. Notably, the analysis reveals that the two-temperature model incorporates an additional contribution to the heat flux due to the gradient of the dynamic temperature, resulting in improved accuracy, especially for high Mach numbers. Results show that the model gives satisfactory shock density and temperature profiles up to Mach 10, with very good agreement observed up to Mach 6.1 compared to the classical NSF model. We conduct an order of magnitude analysis on the dynamic temperature and heat flux gradients appearing in the new constitutive equation using the Mott-Smith method. This analysis highlights the impact of these terms on accurately modeling polyatomic gas behavior in high-speed flows. The effects of bulk viscosity and incoming temperature on shock profiles are also investigated, contributing to a better understanding of shock wave structures in polyatomic gases and their implications for hypersonic flow dynamics.
Density isobar of water and melting temperature of ice: Assessing common density functionals
Authors: Montero de Hijes Pablo , Dellago Christoph , Jinnouchi Ryosuke , Kresse Georg
Published: October 2024

We investigate the density isobar of water and the melting temperature of ice using six different density functionals. Machine-learning potentials are employed to ensure computational affordability. Our findings reveal significant discrepancies between various base functionals. Notably, even the choice of damping can result in substantial differences. Overall, the outcomes obtained through density functional theory are not entirely satisfactory across most utilized functionals. All functionals exhibit significant deviations either in the melting temperature or equilibrium volume, with most of them even predicting an incorrect volume difference between ice and water. Our heuristic analysis indicates that a hybrid functional with 25% exact exchange and van der Waals damping averaged between zero and Becke–Johnson dampings yields the closest agreement with experimental data. This study underscores the necessity for further enhancements in the treatment of van der Waals interactions and, more broadly, density functional theory to enable accurate quantitative predictions for molecular liquids.
Computational fluid dynamics analysis of bypass surgery for a giant internal carotid artery aneurysm
Authors: Panchal Pratik M. , Scaria Sam , Matham Gowtham , Sudhir B. J. , Patnaik B. S. V.
Published: October 2024

Giant intracranial aneurysms are complex and associated with a greater risk of rupture than smaller aneurysms, requiring unique and patient-specific surgical solutions. A giant terminal internal carotid artery aneurysm was surgically managed by a vascular bypass between the internal maxillary artery and the middle cerebral artery using a radial artery graft. This bypass enabled blood flow through the external carotid artery (ECA), as the internal carotid artery was ligated. The present study performs a computational fluid dynamics based assessment of the hemodynamic factors resulting in a successful outcome. The flow domain of interest is extracted from the computed tomography-angio images at two different intervals—before the surgery and after the surgery at t=3 months. An intermediate stage is constructed to reflect the immediate post-surgery (t=0) situation. Numerical simulations are performed using OpenFOAM solver for the non-Newtonian and patient-specific in-flow conditions. Different hemodynamic indicators such as time-averaged magnitude of wall shear stress (|WSS|¯), oscillatory shear index (OSI), and relative residence time (RRT) are derived from the spatiotemporal velocity and pressure data. After the bypass surgery at t=0, the flow facilitated through ECA resulted in a reduction of |WSS|¯ compared to the pre-surgery. Post-surgery (t=0), the region of low |WSS|¯ and high RRT is observed to be responsible for the thrombosis of the aneurysm. Moreover, the present simulation suggests that after three months of surgery, an improvement in values of |WSS|¯ and the reduction in variation of OSI exemplify hemodynamic stability.
A multi-layer multi-configurational time-dependent Hartree approach to lattice models beyond one dimension
Authors: Niermann Tristan , Hoppe Hannes , Manthe Uwe
Published: October 2024

The multi-layer multi-configurational time-dependent Hartree (MCTDH) approach is an efficient method to study quantum dynamics in real and imaginary time. The present work explores its potential to describe quantum fluids. The multi-layer MCTDH approach in second quantization representation is used to study lattice models beyond one dimension at finite temperatures. A scheme to map the lattice sites onto the MCTDH tree representation for multi-dimensional lattice models is proposed. A statistical sampling scheme previously used in MCTDH calculations is adapted to facilitate an efficient description of the thermal ensemble. As example, a two-dimensional hard-core Bose–Hubbard model is studied considering up to 64 × 64 lattice sites. The single particle function basis set size required to obtain converged results is found to not increase with the lattice size. The numerical results properly simulate the finite temperature Berezinskii–Kosterlitz–Thouless phase transition.
Capturing non-Markovian polaron dressing with the master equation formalism
Authors: Iles-Smith Jake , Diba Owen , Nazir Ahsan
Published: October 2024

Understanding the dynamics of open quantum systems in strong coupling and non-Markovian regimes remains a formidable theoretical challenge. One popular and well-established method of approximation in these circumstances is provided by the polaron master equation (PME). In this work, we re-evaluate and extend the validity of the PME to capture the impact of non-Markovian polaron dressing, induced by non-equilibrium open system dynamics. By comparing with numerically exact techniques, we confirm that while the standard PME successfully predicts the dynamics of system observables that commute with the polaron transformation (e.g., populations in the Pauli z-basis), it can struggle to fully capture those that do not (e.g., coherences). This limitation stems from the mixing of system and environment degrees of freedom inherent to the polaron transformation, which affects the accuracy of calculated expectation values within the polaron frame. Employing the Nakajima–Zwanzig projection operator formalism, we introduce correction terms that provide an accurate description of observables that do not commute with the transformation. We demonstrate the significance of the correction terms in two cases, the canonical spin-boson model and a dissipative time-dependent Landau–Zener protocol, where they are shown to impact the system dynamics on both short and long timescales.
A spectrometer design that eliminates incoherent mixing signals in 2D action spectroscopies
Authors: Faitz Zachary M. , Im Dasol , Blackwell Chris J. , Arnold Michael S. , Zanni Martin T.
Published: October 2024

Action spectroscopies use a readout created by the action of light on the molecules or material rather than optical absorption. Ultrafast 2D photocurrent and 2D fluorescence spectroscopies are two such action spectroscopies. Despite their utility, multidimensional action spectroscopies suffer from a background created by incoherent population mixing. These backgrounds appear when the action of one molecule impacts that of another, creating a signal that mimics a fourth-order population response but is really just the convolution of two linear responses. The background created by incoherent mixing is often much larger than the desired foreground signals. In this paper, we describe the physical mechanisms that give rise to the incoherent signals, drawing Feynman paths for each. There are three variations of incoherent signals, differing by their pulse ordering. They all have the same phase dependence as the desired fourth-order population signals and so cannot be removed by standard phase cycling, but they do differ in their polarization responses and dephasing times. We propose, and implement, a spectrometer design that eliminates the background signals for isotropically oriented samples, leaving only the desired fourth-order 2D action spectra. Our spectrometer utilizes a TWINS interferometer and a pulse shaper interferometer, each driven with a different white-light source so that the pulse pairs within each interferometer are phase stable, but not between the two. The lack of phase stability between the two interferometers eliminates two of the three incoherent responses. The third incoherent response is eliminated with the polarization scheme ⟨0, π/2, π/4, π/4⟩. Our spectrometer also enables both 2D photocurrent and 2D white-light spectra to be collected simultaneously, thereby enabling a direct comparison between action and optical detection under identical conditions and at the exact same position on the sample. Using this spectrometer and photovoltaic devices made from thin films of semiconducting carbon nanotubes, we demonstrate 2D photocurrent spectra free of incoherent background.
Studies of the specific current action integral in underwater electrical explosion of butterfly shaped foils
Authors: Asmedianov N. , Liziakin G. , Grikshtas R. , Efimov S. , Krasik Ya. E.
Published: October 2024

Results of experimental research and two-dimensional hydrodynamical simulations of close to critically damped microsecond timescale underwater electrical explosions of butterfly-shaped foils for six different materials are presented. Using current and voltage waveforms along with multi-frame shadow images of the shocks generated in water, the values of the specific action integral, h, were determined. It is shown that values of h can be calculated based on the average current density and that its value (within error bars) does not change in the range of current densities (0.5–1) × 108 A/cm2. The values of h were found to be consistent with those obtained for sub-microsecond underwater electrical explosions of wires made of the same material but differ from those obtained in earlier research with explosion of wires in vacuum.
Electronic structure of zaykovite Rh3Se4, prediction, and analysis of physical properties of related materials: Pd3Se4, Ir3Se4, and Pt3Se4
Authors: Taran Leonid S. , Eremeev Sergey V. , Streltsov Sergey V.
Published: October 2024

In this work, we explore the electronic properties and chemical bonding in the recently discovered mineral zaykovite, the first natural rhodium selenide Rh3Se4. We comprehensively studied the bulk electronic structure, hybridization of rhodium and selenium orbitals, and the influence of spin–orbit interaction on the electronic spectrum, as well as inspected its topological properties. In addition, we investigated the surface electronic structure of zaykovite and revealed the anisotropic Rashba-type spin splitting in the surface states. In addition, using calculations of the phonon spectra and enthalpy of formation, we predicted the family of similar selenides based on other 4d and 5d transition metals such as Ir, Pd, and Pt. The structural and electronic properties of these materials are discussed.
Magnetic and topological phase transition in the symmetry-breaking 1T′-FeSe2 monolayer
Authors: Ruan Qianlian , Lei Wen , Cuono Giuseppe , Autieri Carmine , Xu Ke , Gong Xujia , Wang Wei , Ming Xing
Published: October 2024

Identifying two-dimensional (2D) intrinsic magnetic materials is of great significance for revolutionized spintronic application and fundamental research. Through comprehensive first-principles calculations, we uncover a dynamical and thermally stable monolayer 2D transition metal dichalcogenide compound FeSe2 with an uncommon 1T′ structure and dimerized Fe–Fe bonds. More interestingly, the electronic structure of the 1T′-FeSe2 monolayer depends on the magnetic configurations. The ground state is a ferromagnetic (FM) metal with an obvious magnetocrystalline anisotropy and a high Curie temperature of nearly 400 K. In contrast, the nonmagnetic and antiferromagnetic (AFM) states are insulators, implying the FM to paramagnetic transition will be accompanied by a metal–insulator transition. Furthermore, the FM order transforms to AFM order under a 2.5% in-plane tension, accompanied by a metal–insulator transition. Intriguingly, the AFM trivial insulating state further evolves to AFM topological insulating state by further stretching the in-plane area with a tensile strain of ∼9.1%, which is attributed to the nonsymmorphic symmetry resulting from structural transition by breakdown of the dimerized Fe–Fe bonds. The present work not only is of great scientific interest in exploring unusual magnetic monolayer materials and fascinating phase transitions but also reveals the potential applications of 1T′-FeSe2 monolayers in nanoscale devices.
Electromagnetic-thermal modeling of high-temperature superconducting coils with homogenized method and different formulations: a benchmark
Authors: Dadhich A , Grilli F , Denis L , Vanderheyden B , Geuzaine C , Trillaud F , Sotnikov D , Salmi T , Hajiri G , Berger K , Benkel T , dos Santos G , Santos B M O , Martins F G R , Hussain A , Pardo E
Published: October 2024

High-temperature superconducting coils are used in various large-scale applications, like rotating machines and high-field magnets. However, modeling these coils is a complicated and time-consuming process, especially due to the non-linearity of the current–voltage characteristics of the superconductors and the complex multiphysics involved. In this work, we used a fast homogenized method to model the coupled electromagnetic and electrothermal properties of racetrack and pancake coils for different applications. For this purpose, various formulations wielding homogenization methods are used and benchmarked with each other, as well as with models considering the detailed structure of the HTS tapes. We observe a very good agreement between different models (homogenized and detailed), and we discuss the pros and cons of the inclusion of insulating layers between the turns in homogenization. This work was performed under the collaboration of the COST action modeling teams and can be used as a review of the state-of-the-art superconductor modeling techniques, and a source for the development and benchmark of future numerical methods.
A study on breast cancer image classification based on particle swarm algorithm and transfer learning
Authors: Cai Yingying , Zhang Yong
Published: October 2024

Breast cancer is a major disease that poses a serious threat to the lives and health of women. A new framework was proposed to address the common challenges of high dimensional and data imbalances in image classification. This framework integrates particle swarm optimization (PSO) and transfer learning into a convolutional neural network model based on the ResNet34 architecture. The respective strengths complement each other to enhance the performance and efficiency of the classification model. Through parameter optimization and functional selection of PSO, the global search of the model has been improved. Transfer learning lets the model use large pre-trained datasets to learn more quickly on small sample datasets, which is especially helpful in areas where there are a lot of images that don’t have labels. Experimental findings reveal that our framework attains a 97.83% accuracy rate on the dataset and notably shortens the training cycle, demonstrating its effectiveness in improving breast cancer diagnosis performance with small sample sizes.
Global analysis of tungsten migration in WEST discharges using numerical modelling
Authors: Di Genova S. , Gallo A. , Cappelli L. , Fedorczak N. , Bufferand H. , Tamain P. , Romazanov J. , Morales J. , Marandet Y. , Guillemaut C. , Gunn J.P. , Clairet F. , Brezinsek S. , Ciraolo G. , Serre E. ,   the WEST Team
Published: October 2024

Plasma discharges in the tungsten (W) Environment Steady-state Tokamak (WEST) are strongly impacted by W contamination. In WEST experiments, due to W contamination, the power radiated in the plasma (P
Rad) is on average, around 50% of the total power injected into the plasma (P
TOT). Furthermore, this radiated power fraction (f
Rad) is almost insensitive to plasma conditions. The causes behind this experimental trend are not fully understood. In this contribution, a 3D numerical model is used to analyze the W migration in the WEST boundary plasma in different plasma scenarios. The WEST experimental database is sampled to obtain a scan of simulation input parameters. These parameters mimic the WEST plasma conditions over a chosen experimental campaign. The simulation results are compared to WEST diagnostics measurements (reflectometry, Langmuir probes, and visible spectroscopy) to verify that the simulated plasma conditions are representative of the WEST database. The W contamination trend is analyzed: the W density (n
W) strongly decreases when the radial distance between the separatrix and WEST antennas (Radial Outer Gap, ROG) increases. On the other hand, at a given ROG, n
W increases proportionally with the power entering the scrape-off layer (P
SOL). P
Rad is estimated with a simple 0D model. For a fixed ROG, f
Rad is not sensitive to plasma conditions. These trends are qualitatively and, at times, quantitatively comparable to what is observed in WEST experiments: the simulated trends are related to the poorly screened W influx caused by the erosion of the main chamber Plasma-Facing Components. Thus, this numerical analysis suggests a possible interpretation of WEST experimental trends.
Separation of planar and edge contributions to total capacitance for accurate doping concentration determination in square silicon photodiodes
Authors: Choi E.J. , Kim H.J. , Lee J. , Park H.
Published: October 2024

Accurately determining the doping concentrations of silicon
photodiodes (PDs) is crucial for optimizing their performance in
various applications. This study presents a methodology for
separating the planar and edge contributions to the total
capacitance of square silicon PDs with guard rings. Through
capacitance-voltage measurements, we distinguished planar
capacitance, which reflects the bulk properties of the silicon PD,
from edge capacitance, influenced by device geometry and fringing
fields. We demonstrated that the fabricated PDs with guard rings
surrounding the active area could be effectively modeled using a
coxial-like structure to estimate edge capacitance. Doping
concentrations, depletion widths, and resistivities were determined
through linear fitting of the inverse square of the measured
capacitance per unit area as a function of the reverse bias voltage.
All parameters obtained from the full depletion voltage Vd
,
determined by the intersection of the linear fits for V < Vd
and
 V > Vd
, demonstrated agreement within 1σ. Our results
underscore the importance of accounting for edge effects to
accurately determine doping concentrations from 1/C
2 vs. V 
plots.
A simple device to simulate the radon vertical migration in soil
Authors: Wu Jiulin , Yi Haibo , liu Shuaibin , Sun Jiale , Li Huiying , Liu Zhipeng , Tan Yanliang
Published: October 2024

The knowledge of the soil radon levels is important for the
planning and construction of new buildings in order to estimate the
radon risk and to classify the ground for construction purposes. A
simple device was developed to simulate the vertical migration of
radon in soil. The device simulates the vertical migration of radon
in two different cases. The first case: simulates radon vertical
migration in soil in a natural environment. The top of the device is
open, while the around and bottom are sealed. The second case:
simulates the vertical migration of radon in soil under the surface
of a concrete floor. The device is sealed all around, including the
top and bottom. A total of two sets of experiments were conducted in
this study, each set of experiments simulated the migration of radon
under two different cases. According to the research results, the
potential radon concentration under the concrete floor is much
higher than the natural potential radon concentration. Therefore,
this factor must be fully considered when selecting the building
materials and designing radon protection materials.
Additive manufacturing and in vitro study of biological characteristics of sulfonated polyetheretherketone-bioactive glass porous bone scaffolds
Authors: Zhang Fangyu , Qu Han , Li Guiwei , Zhu Xinhao , Sun Yitong , Cao Qiyuan , Wu Wenzheng
Published: October 2024

Polyetheretherketone (PEEK), a high-performance special engineering plastic, has gradually been used in bone substitutes due to its wear resistance, acid and alkali resistance, non-toxicity, radiolucency, and modulus close to that of human bone. However, its stable biphenyl structure determines strong biological inertness, thus artificial interventions are required to improve the biological activity of fabricated PEEK parts for better clinical applications. This study developed a novel strategy for grafting bioactive glass (BAG) onto the surface of PEEK through sulfonation reaction with concentrated sulfuric acid (H2SO4), aiming to improve the bioactivity of printed porous bone scaffolds manufactured by fused deposition modeling to meet clinical individual needs. In vitro biological study was conducted on sulfonated PEEK-BAG scaffolds obtained by this strategy. The results demonstrated that the optimal modification condition was a 4 h sulfonation reaction with 1 mol l−1 concentrated H2SO4 at high temperature and high pressure. The scaffold obtained under this condition showed minimal cytotoxicity, and the Ca/P molar ratio, yield compressive strength, and compressive modulus of this scaffold were 2.94 ± 0.02, 62.78 MPa, and 0.186 GPa respectively. The presented method provides an innovative, highly effective, and customized strategy to improve the biocompatibility and bone repair ability of printed PEEK bone scaffolds for virous biomedical applications.