bluuebunny/crossref_metadata_2025 huggingface dataset:
Intradural versus Extradural Anterior Clinoidectomy: Comparison of Visual Loss in Patients with Paraclinoid Aneurysms
Authors: de Aguiar Paulo Henrique Pires , Galafassi Giovanna Zambo , Targino Maurício Neres , de Aguiar Pedro Henrique Simm Pires , Doria Hugo Leonardo , Lima Vagner Loduca , Herculano Marco Antonio
Published: December 2024

Introduction Visual deficit after surgical treatment for paraclinoid aneurysms is a problem faced by many neurosurgeons. Anterior clinoidectomy, performed to access the aneurysm, is one the most important steps of the surgery. However, it is also the step related the most with lesions to the optic nerve. The aim of this study was to compare the rate of visual loss between extradural versus intradural clinoidectomy in patients harboring paraclinoid aneurysms which underwent open surgery.

Methods Analysis of 36 patients harboring paraclinoid aneurysms operated by the senior authors between 2020–2022. We compared our results to other series published previously.

Results Fifteen patients underwent intradural clinoidectomy (41.6%), twenty patients extradural clinoidectomy (55.5%) and one patient intra and extradural clinoidectomy (2.7%). The incidence of postoperative visual deterioration was 11.1% (4 patients), all of them were from the extradural clinoidectomy group. Other complications found were cerebrospinal fluid leak (1 patient) and vasospasm followed by diffuse ischemia (1 patient). Visual evoked potential was used in 6 patients (16.6%). In two cases VEP was normal during surgery, however they developed visual deterioration in the postoperative period.

Conclusion Both techniques have advantages and disadvantages, however extradural clinoidectomy showed higher rates of visual deterioration than intradural clinoidectomy. Regardless of the chosen procedure, precise surgical technique is mandatory when dealing with paraclinoid aneurysms.
Vertebral Artery Stenosis Caused by Cervical Osteophyte: A Rare and Reversible Cause of Vertebrobasilar Insufficiency. Case Report
Authors: Cembraneli Pedro Nogarotto , Cavalcante Julia Brasileiro de Faria , Cavalcante Renata Brasileiro de Faria , Cembraneli Italo Nogarotto , Lopes Leonardo Taveira , Cavalcante José Edison da Silva , Cardoso Alessandro Fonseca , Cardoso Chrystiano Fonseca , Zanini Marco Antônio
Published: December 2024

Bow Hunter syndrome manifests when the vertebral artery is compressed following head rotation. Symptomatic compression with vertebral artery stenosis due to cervical osteophytes is a rare cause and occurs due to a progressive degenerative process. In most cases, compression originates anteromedially from the uncinate process and is asymptomatic due to the competence of the contralateral vertebral artery. In the described patient, compression presented superomedially due to osteophytes in the superior articular facet of the C5 vertebra, and the contralateral vertebral artery was obstructed. Careful evaluation with imaging, mainly preoperative 3D angiotomography, is necessary to determine the most beneficial approach for decompression. The treatment of choice for symptomatic compression induced by cervical spondylosis is decompression surgery.
A Rare Case of Drop Metastasis along Lumbar Column of Glioblastoma Multiforme
Authors: Lindner Rafaela Jucá , Gibbon Frederico de Lima , Pitol Guilherme , Gago Guilherme , Vial Antônio Delacy Martini , Ferreira Marcelo Paglioli
Published: December 2024

Glioblastoma Multiforme (GBM) is a malignant primary brain tumor. Drop metastasis is an intradural extramedullary spinal lesion that originates from an intracranial site. It is rare to have the incidence of drop metastases in a patient diagnosed with Glioblastoma Multiforme. We present and discuss a case report on a 35-year-old patient treated for GBM who presented drop metastases after the surgical procedure.
Treatment Options for Intracranial Epidural Hematoma - An Integrative Review of the Past Three Decades
Authors: Pereira Carlos Umberto , Setton Lauro Roberto de Azevedo
Published: December 2024

Introduction Acute epidural intracranial hematoma (IEH) has been considered one of the most relevant neurosurgical emergencies in recent decades due to its high potential for morbidity and mortality. Early diagnosis followed by appropriate treatment results in a more favorable prognosis considering its rapid progression.

Objective To describe the various treatment modalities for IEH in the last three decades and their updates.

Methods Integrative literature review on therapeutic options in IEH treatment. The terms “Epidural hematoma,” “Traumatic brain injury,” and “treatment” were used in the Medline/PubMed, Google Scholar, and SciELO platforms, resulting in 90 articles.

Results Appropriate treatment for IEH depends directly on the Glasgow Coma Scale score obtained during admission, bleeding location, lesion size, presence of associated intracranial injuries, and the neurosurgeon's experience.

Conclusion Initial treatment for IEH is predominantly surgical, with conservative treatment indicated in selected cases. Both neurosurgeons and clinicians must identify characteristic signs and symptoms promptly to avoid treatment delay. Moreover, minimally invasive approaches have gained prominence in recent decades, associated with image-guided procedures, and when well-indicated, result in rapid recovery and lower morbidity.
Cellular Regulation and Oncogenesis of Primary Tumors in the Central Nervous System
Authors: Lemos Leonnardo Altoé Miranda , Stadler Caroline , Lemos Izabelly Constantinov , Pardins Junio Pereira , Sauka Victoria Beatriz Podolan
Published: December 2024

The World Health Organization's system for classifying and grading primary tumors of the Central Nervous System conjectures the clinical-biological course of the oncogenic process based on morphological, genetic, histological, and immunohistochemical parameters. These principles are fundamental for a progression in the classification of these tumors, to guarantee the promotion of a more precise diagnosis. In this sense, it is important to understand the process of oncotic cell formation, which is the result of mutations in intra and extracellular control pathways. In this way, genes that act to induce the cell cycle, under normal conditions, when mutated, can result in a dysregulation of the progress of the cycle, causing alterations in the control factors and, consequently, phenotypic transformations in the cell. Thus, to understand the role of genes in modulating primary tumors in the Central Nervous System, mutations in the genes most prevalently related to Gliomas, Meningiomas, and Medulloblastomas were addressed highlighting their influences on the development of these tumors.
Analysis of Biochemical, Hormonal and Radiological Morphological Measurement Values in Patients with Empty Sella: A Clinical Study
Authors: Ozdemir Alemiddin , Erdogan Ahmet Melih , Sevimoglu Ozge , Durgun Efe Barıs , Ermis Suha Alp , Yalcin Rumeysa , Karaca Yusuf Emin , Temel Sevval Sila , Gedik Sila , Albayrak Ahmet Metehan , Istahlı Eda , Bakar Bulent
Published: December 2024

Objective This study investigated the relationship between radiological morphological findings and hormone levels in patients with empty sella.

Methods Patients (32 female, 3 male) with empty sella detected on radiological images were grouped as “partial empty sella (PBS) group” (subarachnoid space volume < 70%) and “total empty sella (TBS) group” (subarachnoid space volume > 70%). Age, gender, sella volume, pituitary gland thickness, the ratio of subarachnoid space height to pituitary gland height, and diaphragm sellae diameter were measured on radiological images. All patients' blood count results, biochemistry results, and serum hormone values were recorded.

Results Age, complete blood count, serum biochemistry parameters, and hormone levels were not different between PBS and TBS groups. Correlation analysis revealed a negative correlation between gender and subarachnoid space invasion volume, between gender and sagittal width of the sella turcica (ST), between cortisol level and ST axial diameter, between progesterone level and ST axial diameter, between testosterone level and ST axial diameter, between adrenocorticotropic hormone level and ST axial diameter, between TSH level and subarachnoid space invasion rate, between free T4 level and diaphragm sellae sagittal width, and between free T4 level and ST sagittal width.

Conclusion This study showed that some serum hormone values may decrease when the sella tursica dimensions or the volume of subarachnoid space invading the sella tursica increase in patients with empty sella, and therefore, periodic follow-up of hormone levels and radiological images of these patients would be appropriate.
Oscillations of differential resistance of a microscopic point contact in He II
Authors: Khotkevich A. V. , Yanson I. K.
Published: December 2024

Steady-state differential resistance oscillations of a normal point contact immersed in He II were studied experimentally. The oscillations are observed in the first and second derivatives of the characteristics as functions of current or voltage bias at a fixed bath temperature below Tλ or as a function of temperature T < Tλ at a fixed bias. In He I (for both equilibrium and subcooled vapor pressure) and in gas, stationary differential resistance oscillations are absent. The effect of contact resistance, electrode thickness, and surface state at the helium boundary on the oscillations is studied and a correlation with the phonon spectrum of the metal studied is noted. A model is presented, which takes account of features in heat transfer to He II from a microscopic point contact under significant overheating: differential resistance oscillations are related to the appearance of local vapor regions in the contact region at the helium boundary during transition to the film boiling regime in He II.
Exciton–magnon coupling in antiferromagnets and its influence on the energy spectrum of excitons
Authors: Loginov A. A. , Popov V. A.
Published: December 2024

Based on the vector representation of the Hamiltonian of exchange electrostatic interactions in an antiferrodielectric, the effectiveness of the approximation of large spin (S0) is demonstrated. The amplitudes of exciton–magnon coupling and the exciton density operators are found in the leading approximation in S0−1. Properties of the coupling amplitudes are analyzed, and the temperature dependence, due to these interactions, of the position of the exciton bands in magnetic fields are calculated.
The Hall effect in spin glasses — copper alloys with manganese, iron, and cobalt
Authors: Vedyaev A. V. , Ivanov V. Yu. , Cherenkov V. A.
Published: December 2024

The electrical resistivity, Hall effect, and magnetic susceptibility of spin glasses (alloys of copper with iron, manganese, and cobalt) have been studied at temperatures between 4.2−52 °K in magnetic fields up to 13 T. Low-temperature maxima were observed in the Hall voltage and magnetic susceptibility. The anomalies in the Hall effect are explained using the Beal-Monod–Weiner theory.
Peculiarities of exciton–magnon absorption of light by antiferromagnetic CsMnCI3 · 2H2O due to the low dimensionality of its magnetic structure
Authors: Novikov V. P. , Kachur I. S. , Eremenko V. V.
Published: December 2024

The transition 6Alg(6S) → 4T2(4D) in the optical light absorption spectrum of CsMnCl3 · 2H2O, which has the best developed fine structure, is investigated experimentally. Peculiarities of exciton–magnon light absorption, stemming from the one-dimensionality of the crystal and absent in spectra of three-dimensional antiferromagnetic crystals, are discovered. The exciton–magnon absorption has a clearly expressed band nature. In the region of the exciton line, fine structure of the exciton–magnon absorption is observed in the form of two narrow bands. It turns out that it is possible to observe directly in the hot exciton–magnon absorption spectrum the position of the maxima of the initial segment of the magnon density of states and to measure the activation energy of both branches of the spin-wave spectrum of CsMnCl3 · 2H2O.
Effect of quasilocal modes on rms atomic displacements and impurity resistivity of anisotropic crystals
Authors: Morgun V. N. , Syrkin E. S. , Feodos’ev S. B.
Published: December 2024

Impurity-induced relative changes in the temperature dependent part of the rms displacements are considered for a concrete model of anisotropic crystal in different crystallographic directions. The calculations are carried out by the Jacobian-matrix method developed by Peresada. The Δi values for each direction display a maximum due to the separation of quasilocal modes. The relation between Δi and the relative change in the temperature-dependent part of the resistivity in the i direction provides a new possibility for experimental detection of quasilocal-mode splitting. The temperature-dependent impurity-induced resistivity of Be−Cu alloys is measured. Theoretical and experimental results are compared.
Distributed NE and GNE seeking for heterogeneous multi-player games over directed communication networks
Authors: Tao Qianle , Liu Yongfang , Xian Chengxin , Zhao Yu , Wen Guanghui
Published: December 2024

The non-cooperation game with heterogeneous dynamics is of both theoretical significance and practical relevance because of its extensive penetration into various fields, such as the game confrontation composed of unmanned aerial vehicles and unmanned vehicles or the power generation systems with varied turbine assemblies. To solve such a game problem, this paper investigates distributed Nash equilibrium (NE) and generalized Nash equilibrium (GNE) seeking problems for heterogeneous multi-player systems in non-cooperation games. First, by incorporating the output regulation technique, a distributed NE seeking strategy is designed for heterogeneous multi-player games over undirected communication networks. Then, the GNE seeking problem subject to coupling constraints among multiple players is further studied and a distributed GNE seeking strategy is developed by utilizing the Lagrange multiplier and the output regulation technique. Second, in the case of directed communication networks, both distributed NE and GNE seeking strategies are proposed by employing new type of auxiliary variables to compensate for the unbalanced networks. Compared with some existing results on distributed NE and GNE seeking strategies, both the dynamics of players and communication networks are extended further. Finally, numerical simulations are presented to show the effectiveness of the NE and GNE seeking strategies.
Reconstruction of soft x-ray emission in MAST Upgrade
Authors: Steward B. A. , Cecconello M. , Bowman C. ,   MAST-U Team
Published: December 2024

Understanding the confinement of fast ions is crucial for plasma heating and non-inductive current drive, i.e., for the operation of a fusion reactor. Interactions between fast ions and magnetohydrodynamic instabilities can reduce the performance of fusion reactions. Measuring the spatial shape and amplitude is crucial for constraining numerical modeling of the interaction between fast ions and these instabilities. Soft x rays can be used to study these magnetic instabilities. In particular, SXR tomography is used to reconstruct the two-dimensional profile of the SXR emissivity requiring only line integrated measurements, thus providing the spatial structure of the instabilities. This work presents SXR tomography reconstruction performed on synthetic SXR emissions from the Mega Ampere Spherical Tokamak Upgrade device. The synthetic SXR emissions are derived from time dependent tokamak transport data analysis code (TRANSP/NUBEAM) simulations. Different tomographic reconstruction models are compared, and the effect of two additional fans of intersecting lines of sight on the reconstructions’ performances is investigated. The additional intersecting lines of sight greatly improve the accuracy of the reconstructions.
Improvement of recessed MOS gate characteristics in normally-off AlN/GaN MOS-HFETs with N2/NH3 thermal treatment
Authors: Kato Daimotsu , Kajiwara Yosuke , Ono Hiroshi , Shindome Aya , Huang Po-Chin , Tajima Jumpei , Hikosaka Toshiki , Kuraguchi Masahiko , Nunoue Shinya
Published: December 2024

This study investigated the metal–oxide–semiconductor gate characteristics of recessed-gate AlN/GaN metal–oxide–semiconductor-heterojunction-field-effect transistor with N2/NH3 thermal treatment. The gate-channel mobility in recessed-gate structures formed by the inductively coupled plasma-reactive ion etching method is degraded due to plasma-induced damage. The application of thermal treatment to etch-damaged GaN surfaces was observed to re-form a clear step-terrace structure, effectively reversing the effects of the etching damage. A corresponding enhancement in peak field-effect mobility was experimentally verified, with an increase from a pretreatment value of 656 to 1042 cm2/V·s after thermal treatment. Concurrently, an improvement of the lower gate-leakage current by 1–2 orders of magnitude was measured. This thermal treatment method can reduce crystal defects at deep levels of 1.8–2.9 eV below Ec on the etched GaN surface. In particular, this N2/NH3 thermal treatment approach could potentially contribute to the reduction of deep levels such as atomic displacement, gallium vacancies, and those complexes generated by inductively coupled plasma-reactive ion etching.
CO adsorption on CeO2(111): A CCSD(T) benchmark study using an embedded-cluster model
Authors: Vázquez Quesada Juana , Bernart Sarah , Studt Felix , Wang Yuemin , Fink Karin
Published: December 2024

A benchmark model that combines an embedded-cluster approach for ionic surfaces with wavefunction-based methods to predict the vibrational frequencies of molecules adsorbed on surfaces is presented. As a representative case, the adsorption of CO on the lowest index non-polar and most stable facet of CeO2, that is, (111) was studied. The CO harmonic vibrational frequencies were not scaled semiempirically but explicitly corrected for anharmonic effects, which amount to about 25 cm−1 with all tested methods. The second-order Møller–Plesset perturbation method (MP2) tends to underestimate the CO harmonic frequency by about 40–45 cm−1 in comparison with the results obtained with the coupled-cluster singles and doubles with perturbational treatment of triple excitation method [CCSD(T)] and independently from the basis set used. The best estimate for the CO vibrational frequency (low-coverage case) differs by 12 cm−1 with the experimental value obtained by infrared reflexion absorption spectroscopy of 1 monolayer CO adsorbed on the oxidized CeO2(111) surface. In addition, a conservative estimate of the adsorption energy of about −0.22 ± −0.07 eV obtained at the CCSD(T) level confirms the physisorption character of the adsorption of CO on the CeO2(111) surface.
Bioinspired porous magnetoresponsive soft actuators with programmable 3D curved shapes
Authors: Zhu Hanlin , Ye Xin , Tian Yuanyuan , Ge Yangwen , Huang Hui , Lim Zheng Han , Gao Ming , Liu Binbin , Zhao Yan , Zhou Kun , Jiang Chao
Published: December 2024

Shape-programmable magnetoresponsive soft actuators (SMSAs) are highly desirable for diverse applications in soft robotics and minimally invasive medicine. Current methods face challenges in achieving programmable magnetoresponsive three-dimensional (3D) shapes with non-uniform and continuously adjustable curvatures, which are crucial for the highly effective locomotion of SMSAs. Here, we propose an approach that integrates bioinspired pore design with mechanically guided magnetization, enabling programmable magnetoresponsive complex shapes with non-uniform and continuously adjustable curvatures. Various magnetoresponsive developable and non-developable surfaces, along with biomimetic 3D curved shapes, were prepared. The prepared SMSAs exhibit actuation rates of up to 20 s−1. Furthermore, an inchworm-inspired soft crawling robot capable of steering, navigation, obstacle crossing, and cargo transportation was developed, achieving a locomotion speed of up to 1.2 body lengths per second. This work breaks through the design possibilities for SMSAs, enhances the actuation rates of soft actuators, and advances the application of SMSAs in soft crawling robots.
On quantitativeness of diffraction-limited quantitative phase imaging
Authors: Bouchal Zdeněk , Bouchal Petr , Chmelíková Tereza , Fiurášek Jaromír
Published: December 2024

Quantitative phase imaging (QPI) has advanced by accurately quantifying phase shifts caused by weakly absorbing biological and artificial structures. Despite extensive research, the diffraction limits of QPI have not been established and examined. Hence, it remains unclear whether diffraction-affected QPI provides reliable quantification or merely visualizes phase objects, similar to phase contrast methods. Here, we develop a general diffraction phase imaging theory and show that it is intrinsically connected with Rayleigh’s resolution theory. Our approach reveals the entanglement of phases under restoration, imposing diffraction bounds on spatial phase resolution and, unexpectedly, on phase accuracy. We prove that the phase accuracy depends on the size, shape, and absorption of objects forming the sample and significantly declines if the object size approaches the Rayleigh limit (a relative phase error of −16% for an Airy disk-sized object with low phase shift). We show that the phase accuracy limits can be enhanced at the cost of deteriorated phase resolution by attenuating the sample background light. The QPI diffraction limits are thoroughly examined in experiments with certified phase targets and biological cells. The study’s relevance is underscored by results showing that the phase accuracy of some structures is lost (a relative phase error of −40%) even though they are spatially resolved (a phase visibility of 0.5). A reliable procedure is used to estimate phase errors in given experimental conditions, opening the way to mitigate errors’ impact through data post-processing. Finally, the phase accuracy enhancement in super-resolution QPI is discovered, which has not been previously reported.
Numerical investigation of supersonic separator's performance in natural gas dehydration
Authors: Rahvard Ahmad Jahani , Lakzian Esmail , Khoshnevis Abdolamirbak , Kim Heuy Dong
Published: December 2024

In this study, a validated computational fluid dynamics code was established to investigate the condensation of a binary CH4–H2O mixture in a supersonic separator. The condensation parameters were numerically calculated, and then the influence of divergence angle, swirling intensity, and H2O mass fraction on efficiency was evaluated. The results showed that increasing the divergence angle raised the nucleation rate and moved the location of nucleation toward the throat. In addition, increasing the divergence angle enhanced the droplet number but it decreased the droplet radius. Because of these effects, an increase in the wetness fraction at the nozzle outlet by 5.7% was attained. Also, the results demonstrated that increasing the swirl intensity pushed the nucleation place toward the nozzle throat. It means that the more substantial the swirl intensity, faster the nucleation. Furthermore, the maximum nucleation rate was increased by enhancing the swirling intensity. The droplets number was increased by enhancing the swirl intensity, which caused to higher the wetness fraction by 1.2%. It was also found that although both methods improved the efficiency of the supersonic nozzle by increasing the water mass fractions, the inlet flow swirling method performed better than the divergence angle changing method. An optimal case was introduced by using the technique for order of preference by similarity to ideal solution method. The criteria were outlet wetness fraction, kinetic energy, and pressure loss ratio. Finally, the proper location for wet outlet was determined. The result showed that the supersonic separator that has a wet outlet closer to the throat is more efficient.
Modal analysis of turbulent flows simulated with spectral element method
Authors: Ranjbar Mohammadmahdi , Mostafavi Ali , Rajendran Prasanna Thoguluva , Komperda Jonathan , Mashayek Farzad
Published: December 2024

Leveraging the high-order nature of spectral element methods, this work introduces a methodology that enables instantaneous, local analysis of turbulent flows through a transformation to a modal space. It also introduces a dynamic explicit modal filter (DEMF) for removing the excess energy in large-eddy simulation of turbulent flows. The transformation is achieved through the application of the discrete Chebyshev transform to nodal solution values, and the resulting modes are employed to characterize and distinguish different turbulent flow properties. Implementing direct numerical simulation (DNS), a qualitative explanation of how modes can assess flow directionality and turbulence properties is provided by considering the modal representation at different locations for different turbulent flows. Additionally, reducing the resolution from DNS, it is shown how modes can qualitatively assess local flow resolvedness. A quantitative assessment of local flow resolvedness is conducted by calculating sequential energy levels from the modes and then comparing them between DNS and under-resolved cases. These energy levels correspond to different scales of motion and their behavior changes as turbulence intensifies and decays. It is observed that flow under-resolvedness manifests itself in the increased magnitudes of higher energy levels corresponding to small scales of motion. Finally, the new DEMF is discussed, which is triggered locally by comparing the local Kolmogorov length scale and the average grid spacing. The filter removes the excess energy in the detected under-resolved regions by selectively removing the energy of the modes that contribute to higher energy levels.
An optimized anisotropic pressure fluctuation model for the simulation of turbulence-induced vibrations
Authors: Zwijsen K. , Marreiros de Freitas A. , Tajfirooz S. , Frederix E. M. A. , van Zuijlen A. H.
Published: December 2024

A significant aspect of the economic performance and safety of a nuclear reactor involves maintaining the integrity of the fuel rods, which are susceptible to Turbulence-Induced Vibrations (TIV) resulting from the axial flow of the coolant. TIV can instigate severe repercussions, including structural damage such as fatigue and wear. TIV can be studied numerically, using Fluid–Structure Interaction( FSI) simulations. However, high-resolution approaches are computationally too expensive to use for complex FSI simulations, while Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations severely underpredict the displacement amplitudes of the vibrations as they only resolve the mean flow. Evolving from this shortfall, this paper focuses on a recently developed Anisotropic Pressure Fluctuation Model (AniPFM). This model generates a synthetic velocity fluctuations field, which is used to solve for the pressure fluctuations. Using this model, together with URANS, is a possible way to simulate the excitation mechanisms of TIV of fuel rods in a computationally cheaper way. While previous research has highlighted the potential of this model, there are parameters, definitions, and constants whose impacts on the model are not yet fully understood. Therefore, a comprehensive effort is undertaken to fine-tune the model, optimize its performance, improve understanding of it and further validate it. This is done by applying AniPFM to both pure flow and FSI cases, using high-resolution numerical and experimental data as reference and for comparison. With the optimized model, a substantial decrease in average difference from the experimental data is found for the FSI case under consideration, when compared with the unoptimized version of AniPFM.
All-fiber fast coherent LiDAR for ranging and velocimetry based on optical comb injection
Authors: Lin Chenxiao , Wang Yifan , Li Zimo , Tan Yidong
Published: December 2024

Frequency-modulated continuous-wave light detection and ranging (LiDAR) is a powerful ranging technique that offers inherent resistance to ambient light and the capability to simultaneously measure both distance and velocity. However, conventional LiDAR systems often face challenges with environmental interference and achieving a balance between demodulation complexity, data-refresh rate, and precision. Here, we introduce an all-fiber LiDAR system that utilizes optical comb injection for high-precision ranging and velocimetry. Owing to the injection locking process, the beam output from slave lasers inherits the linear and fast frequency modulation features of the injected optical comb sidebands generated through an electro-optics modulator while maintaining a stable output power with little phase noise, solving a big concern in traditional external modulation schemes. The unique dual-sideband locking and common-path design enhance stability and anti-interference ability, enabling the system to possess a high data-refresh rate of over 10 kHz and a high precision of 500 μm without complex algorithms or compensation circuits. Dynamic ranging and imaging of noncooperative targets are also demonstrated. With the advantages of fast and noncontact measurement, high precision and stability, and anti-interference ability, the proposed system has potential applications in automatic driving, machine control, and intelligent robotics.
Modeling and simulation of dielectrophoretic sorting of tenogenically differentiating mesenchymal stem cells for high throughput
Authors: Oladokun Raphael , Srivastava Soumya K. , Schiele Nathan R. , Pei Ming
Published: December 2024

Mesenchymal stem cell (MSC)-based regenerative therapies are promising for healing tendon injuries and tears, due to their potential to differentiate into tenogenic cells. However, generating homogeneous populations of tenogenically differentiated stem cells remains a big challenge, as non-differentiated cells can lead to post-transplantation complications. Therefore, a homogenous sample of tenogenically differentiated MSCs is critical for advancing tendon therapies and avoiding uncontrolled cell growth or non-tendon tissue formation (e.g., ectopic bone). This work is focused on designing and simulating a dielectrophoretic (DEP)-based label-free, microfluidic platform to selectively sort and enrich tenogenically differentiated MSCs (tMSCs) from undifferentiated MSCs. Using particle tracing, creeping flow (transport of diluted species model), and electric current physics modules in the COMSOL Multiphysics simulation software package, the sorting was simulated within a two-stage microfluidic device operating at a sinusoidal frequency of 160 kHz. The optimal separation efficiency and purity are achieved at an inlet velocity of 400–1000 μm/s, with specific voltage configurations, enabling recovery of one million tMSCs in ∼3 h. Results demonstrate a near-linear relation between recovery time and particle count at the outlet boundaries and selected surfaces, indicating consistent throughput across varying conditions. This study demonstrates that DEP can offer a scalable, efficient, and label-free method for enriching tMSC populations with high selectivity, enhancing more prospects for MSC-based tendon therapies and advancing the development of microfluidic sorting devices for regenerative medicine applications.
A large-eddy simulation study of the swirl-switching mechanism in toroidal pipes
Authors: Zhang Ke-Dong , Wang Wen-Hua , Zhao Zi-Han , Piao Tai-Wei , Xiu Yuan-Bo , Tu Chao-Fan , Wang Lin-Lin , Du Ya-Zhen , Huang Yi
Published: December 2024

Large-eddy simulation was conducted on turbulent flow in toroidal pipes of various lengths to study the impact of streamwise fluctuation structures on the secondary motion and explore the origin of the swirl-switching phenomenon. Proper orthogonal decomposition analysis was carried out to identify the primary coherent structures in the flow field and determine the oscillation frequencies of the swirl switching. The results show that high-frequency switching (St > 0.05) is closely related to the spatial scale of very-large-scale motion (VLSM), and that its streamwise extension is approximately the characteristic length corresponding to the switching frequency. Conversely, the characteristic length of low-frequency switching (St ≤ 0.05) is significantly larger than the physical model, which is not attributed to the spatial scale of streamwise fluctuations but rather to the temporal oscillations of the VLSM. Due to the sensitivity of the VLSM structure, the alignment mechanism of VLSM changes under vertical excitation, leading to a reduction in the streamwise characteristic length and an increase in the frequency of swirl switching. The spatiotemporal variations of the VLSM feedback into the frequency of swirl switching, thus confirming the significant effect of streamwise fluctuation. Additionally, the wall shear stress exhibits oscillation frequencies associated with swirl switching and VLSM, indicating a correlation between flow field fluctuations and wall shear stress, which could potentially contribute to material erosion and local resonance.
Assessing Reynolds and Jakobsson–Floberg–Olsson models for infinitely long water-lubricated partial journal bearings: Static and dynamic performance predictions compared to computational fluid dynamics analysis
Authors: Guo Juan , Cohen Igal , Goltsberg Roman , Han Yanfeng , Groper Morel
Published: December 2024

This study evaluates the validity of two numerical models in predicting the performance of infinitely long water-lubricated partial journal bearings (IWLPJB): the non-mass-conserving Reynolds model (RBC) and the mass-conserving Jakobsson–Floberg–Olsson model (JFO). Building upon previous research on inadequately lubricated partial, long water-lubricated bearings, this work employs an efficient modeling approach (EMA) to implement these models, with results compared against computational fluid dynamics (CFD) analysis. A comprehensive evaluation of numerical models under realistic operating conditions is provided, specifically addressing the negative pressure cavitation phenomena of water-lubricated systems. The analysis focuses on conformal surfaces of IWLPJB, examining both static and dynamic performance predictions at the high eccentricity ratios typically encountered in industrial applications. The study examines both untextured and textured cases, assessing bearing performance parameters including maximum hydrodynamic pressure, attitude angle, load-carrying capacity, coefficient of friction (COF), and eight dynamic coefficients. The results indicate that for untextured and partially textured cases, both models provide reliable predictions of the performance parameter values at the studied high eccentricity ratios (0.9–0.98), despite RBC's inaccurate prediction of the cavitation region. Additionally, the differences between the two models are not sensitive to the studied texture depths (7.8–52 μm). For the fully textured case, although prediction errors increased, both models remain applicable for a wide range of performance parameters except for the COF. Notably, this study reveals that the predictive capability of the RBC model for both static and dynamic performance, particularly in textured cases, has been somewhat underestimated in previous research.
Low-threshold absolute parametric decay instability of microwave beam in X2 ECRH experiments with monotonic density profile
Authors: Popov A. Yu. , Nagovitsyn A. A. , Gusakov E. Z.
Published: December 2024

It is shown that the absolute parametric decay instability of a microwave beam of a finite width, resulting in the excitation of two electron Bernstein waves, can occur at monotonic parameters of the background plasma in X2-mode ECRH experiments at a modest pump power. The excitation of daughter waves, whose power deposition localization differs from that of the pump wave, can potentially explain the broadening of the power deposition profile and lack of the pump power absorbed in the electron cyclotron resonance layer that has been found in X2-mode ECRH experiments.
Analyzing the threshold angles for vortex formation in shallow water open channels
Authors: Wang Haidong , Xu Dong , Ran Qihua , Yuan Saiyu , Tang Hongwu
Published: December 2024

Vortices are widely present in nature and hydraulic engineering, particularly in rivers, lakes, and open channels. Most vortices in water bodies are shallow, meaning the horizontal scale of the vortex is significantly larger than the water depth. While vortex studies exist in hydraulic engineering, they primarily focus on practical projects. The thresholds for vortex formation under varying sudden expansion angles in open channels, as well as the extent of vortex fluctuations, remain unclear. We employed the Shear Stress Transport k-ω turbulence model to analyze the flow field structure by testing 24 different sudden expansion angles, based on the characteristics of shallow water vortices in the sudden expansion section of an open channel. The results indicate that when the vortex area is defined as 0.1% of the total area of the sudden expansion section, the vortex generation threshold is 10.61° under the Q criterion, and 10.71° under the Ω criterion. Contrary to the common assumption that a larger sudden expansion angle results in a larger vortex, the optimal angle for controlling vortex formation is 19.33°. This angle significantly reduces vortex fluctuations, especially when the sudden expansion angle is 18°, with a reduction rate of 79.11% in the vortex area under the Q criterion. Thus, studying the different expansion angles of shallow water vortices in open channels offers critical design references for hydraulic engineering and has broader implications for shallow water flow regimes.
Deformation of a macroscopic yield stress hydrogel during the free fall of a sphere
Authors: Sgreva Nicolò R. , Davaille Anne
Published: December 2024

We investigate the deformation of a macroscopic yield stress fluid consisting of a mixture of water and hydrogel (superabsorbent polymer) with high solid volume fractions and different grain size distributions during the settling of a sphere. The fluid's rheology combines viscous, elastic, and plastic behaviors and is described by a shear-thinning yield stress model. Experiments were conducted in two motion regimes: the continuous fall, where the sphere reaches a constant terminal velocity, and the intermittent regime, with alternating periods of motion and no-motion. Particle image velocimetry and spatiotemporal images of laser-illuminated fluid cross sections were used to determine the yield surface and analyze local grain motion dynamics. In both regimes, a yield surface similar to an ovoid spheroid is observed. A scaling law is derived for lateral deformation (perpendicular to the fall direction), dependent on sphere size and Yield number (Y). This scaling law provides reliable estimations of maximum deformation widths, consistent with experiments in the literature using different yield stress fluids. For all fluid samples used, the flow within the yielded region shows a strong fore-aft asymmetry, characterized by a negative wake at the back of the sphere related to the elastic component of the bulk deformation. In the intermittent motion regime, we find that the transition from no-motion to motion is associated with reaching a maximum level of compression or triggering sufficient irreversible plastic events in the region of fluid under compression. This leads to a sudden avalanche-type of event where stresses are relaxed and the sphere starts moving downward again.
Effects of lacunocanalicular morphology and network architecture on fluid dynamic environments of osteocytes and bone mechanoresponses
Authors: Fu Ruisen , Yang Haisheng
Published: December 2024

Osteocytes, situated within the lacunocanalicular network (LCN) of the bone matrix, play crucial roles in sensing mechanical signals and orchestrating bone adaptive responses. Alterations in LCN structure could significantly modify the fluid dynamic microenvironment of osteocytes, thereby influencing bone mechanoresponses (BMRs). However, a comprehensive understanding of this tissue remains elusive. In this study, a multi-scale model of whole bone-LCN was developed to systematically investigate the effects of lacunocanalicular morphology (lacunar volume [Lc.V] and canalicular area [Ca.S]) and network architecture (lacunar density [Lc.ρ] and canalicular density [Ca.ρ]) on fluid shear stress (FSS) within the LCN and BMR predicted by fluid flow. Furthermore, the relationships between fluid flow within the LCN and BMRs were examined in two specific scenarios: aging and lactation. Results demonstrated that changes in lacunocanalicular morphology (Lc.V and Ca.S) primarily influenced the intensity of fluid flow, while alterations in the LCN (Lc.ρ and Ca.ρ) largely affected the distribution of fluid flow. Increases in Lc.V or decreases in Ca.S increased FSS, whereas decreases in Lc.ρ or increases in Ca.ρ reduced FSS. Compared with other structural parameters, alterations in Ca.ρ had the greatest effect on FSS, while BMR primarily depended on changes in Lc.V and Ca.S. In agreement with experimental observations, aging- or lactation-induced changes in LCN structure (and fluid dynamics) were associated with reduced (−50%) or increased (+20%) bone responses to mechanical loading, respectively. These findings suggest that modifications in lacunocanalicular morphology and network architecture can substantially impact the fluid dynamic microenvironment for mechanosensing osteocytes and, consequently, BMRs.
Multimodal LSPR-enhanced crayfish-type optical fiber sensor for ultra-sensitive detection of Shigella sonnei using hybrid nanomaterials
Authors: Zhang Qi , Singh Ragini , Nedoma Jan , Min Rui , Marques Carlos , Zhang Bingyuan , Kumar Santosh
Published: December 2024

This paper designs a biophotonic sensor that utilizes the localized surface plasmon resonance (LSPR) effect to detect Shigella sonnei (S. sonnei) with high sensitivity, featuring a novel crayfish-type optical fiber structure. Diseases and food safety caused by S. sonnei have become a public health issue of common concern around the world. This sensor is specifically designed for the detection of S. sonnei. This sensor has the advantage of being easy to operate, requires no labeling, and has high specificity. Excite the LSPR effect using gold nanoparticles (AuNPs). To enhance the LSPR effect, a fusion structure of multimode fiber and seven-core fiber was utilized, as was a crayfish-type optical fiber structure. Using Rsoft to simulate the crayfish-type optical fiber structure, it is concluded that the structure has excellent evanescent field. S. sonnei antibodies were used to improve the specificity of the sensor. Tungsten disulfide thin layer (WS2-thin layer) and zinc oxide nanowires were used to increase the surface area for antibody attachment. The linear range of the sensor was 1 × 100–1 × 107 CFU/ml, the sensitivity was 0.378 nm/lg (CFU/ml), and the limit of detection was 4.78 CFU/ml. The reproducibility, reusability, selectivity, and stability of the sensor were tested. The test results showed that the sensor had excellent performance. In addition, the sensor was tested with real food samples. This research has far-reaching significance for biophotonic sensors and human health.
Energy-minimized mobilization of trapped non-aqueous phase liquids ganglia in three-dimensional biconical pores: Insights from surface evolver simulations
Authors: Zhang Lei , Imani Gloire , Sun Hai , Fan Dongyan , Fu Shuaishi , Yang Yongfei , Yao Jun
Published: December 2024

The mobilization of a ganglion is of great significance in various domains, including soil contamination. For effective soil remediation, it is essential to correctly characterize the behavior of trapped nonaqueous phase liquids (NAPLs). Therefore, in this study, a biconical pore structure is employed to investigate the conditions of mobilization of a trapped NAPL ganglion using Surface Evolver software. The results showed that in the three-dimensional model, the ganglion can take a sequence of saddle-shapes of increasingly negative mean curvature as it approaches the middle of the pore, and depending on the contact angle, it can cross the bulge through two main mechanisms: an asymmetric jump and an asymmetric crawl. These behaviors are triggered by the fact that the ganglion seeks the path of low energy. The pressure difference is observed to decrease with pore occupancy (from n = 2 to n = 2.5) and then increase (to n = 2.75). The same behavior occurs for pore occupancy n + 1; thus, pore occupancy plays a significant role only within a single pore. For a ganglion occupying the whole pore, the critical pressure is symmetric about the neutral wettability, namely, θ = 90°. For the pores partially occupied by the ganglion, the wettability condition of the pore wall can favor ganglion mobilization depending on pore occupancy. Furthermore, the contact angle hysteresis leads to a considerable increase in resistance to ganglion mobilization. These insights provide a deeper understanding of the pore-scale dynamics involved in NAPL mobilization, informing the design of more effective remediation strategies.
Experimental and numerical investigation of unsteady thermal reactive flow characteristics of aluminum-based nitrate ester plasticized polyether propellant across a wide pressure range
Authors: Chen Kaixuan , Xue Xiaochun , Ye Zhenwei , Yu Yonggang
Published: December 2024

Aluminum-based nitrate ester plasticized polyether (NEPE) propellant, a high-energy solid propellant extensively employed in the aerospace industry for launch vehicles, faces significant challenges due to its unsteady reactive combustion flow characteristics not being fully understood. This lack of understanding significantly hampers its practical application and obstructs progress in deep space exploration. Therefore, it is imperative to delve into the energy mechanisms driving Al-based NEPE propellant. In our study, experimental and numerical approaches were employed to investigate the unsteady thermal reactive flow characteristics of aluminum (Al)-based NEPE propellant over a broad pressure range. The chemical kinetic model we proposed demonstrated remarkable predictive capabilities for Al-based NEPE propellant. Our findings underscore that the content and size distribution of ammonium perchlorate (AP) particles markedly influence the reactive flow intensity, affecting the burning rate of propellant. Simulation results from Al-based NEPE disk pack regression revealed that surfaces with a higher concentration of Al particles exhibited lower reactive intensity, while surfaces with a higher AP content displayed higher average transient reactive intensity. This research provides a more profound understanding of the thermal reactive processes inherent in aerospace propellants, facilitating enhanced grain design for solid propellants to achieve superior burning efficiency.