bluuebunny/crossref_metadata_2025 huggingface dataset:
Measures of Knee Capability in Handball Players Differ by Age: A Cross Sectional Study
Authors: Mayer Constantin , Rühlemann Alina , Busch Andre , Jäger Marcus
Published: August 2022

The return to sport after knee injury is challenging. This is burdensome for sports with a high incidence of injuries, such as team handball. Various tests guide decision making, but often the athlete’s preinjury performance of these measures remains unknown. Moreover, objective return-to-sport criteria of a matching population are missing. The purpose of this study was to evaluate objective measures of knee capability in handball depending on players’ age. Two hundred sixty-one handball players performed a functional test battery designed to evaluate knee capability after an anterior cruciate ligament injury: two- and one-legged stability analysis, jumps, speed tests, and agility assessments. For age-specific evaluation, athletes were divided into three age groups (16–19; 20–29;≥30 years). Male players showed differences in two and one-legged jumping height (p<0.02) as well as power per body weight (p<0.01) between age groups. Young female players reached better results in two-and one-legged stability. Besides the quick feet test, results of females did not differ between age groups. Functional knee stability in healthy handball players is partly influenced by age, and females show better results in stability and male athletes in power measurements. This aspect should be considered for return to sports testing and underlines the importance of performance measures in athletic testing.
The Efficacy of Physical Fitness Training on Dance Injury: A Systematic Review
Authors: Dang Yanan , Chen Ruoling , Koutedakis Yannis , Wyon Matthew Alexander
Published: August 2022

Greater levels of physical fitness have been linked to improved dance performance and decreased injury incidence. The aim was to review the efficacy of physical fitness training on dance injury. The electronic databases CINAHL, Cochrane Library, PubMed, Web of Science, MEDLINE, China National Knowledge Infrastructure were used to search peer-reviewed published articles in English or Chinese. Studies were scored using Strength of the Evidence for a Conclusion and a risk bias checklist. 10 studies met the inclusion criteria from an initial 2450 publications. These studies offered physical fitness training for professional (n=3) and pre-professional dancers (n=7), participant sample size ranged between 5 to 62, ages from 11 to 27 years, and most participants were females. Assessment scores were classified as Fair (n=1), Limited (n=7), and Expert Opinion Only (n=2) and risk of bias scores ranged from 22.7–68.2%. After physical fitness training, 80% of studies reported significant benefits in injury rate, the time between injuries, pain intensity, pain severity, missed dance activities and injury count. This review suggests that physical fitness training could have a beneficial effect on injury incidence in dance. The evidence is limited by the current study methodologies.
Association of Muscle Fibers with Histopathology in Doughnut Specimens Following Stapled Hemorrhoidopexy and Their Impacts on Postoperative Outcomes
Authors: Narayanaswamy Chetty Y. V. , Sreevathsa M. R. , Chowdari G. Akhil , Rao Koteshwara
Published: August 2022

Background Stapled hemorrhoidopexy is widely practiced worldwide since its introduction to the world of proctology and replaced conventional hemorrhoidectomy in treating hemorrhoids. The technique of executing the procedure dictates the outcomes and complications. Here, we attempted to establish the cause of postoperative complications and attributed them to the presence of muscle of fibers in the excised doughnut specimens.

Materials and Methods A prospective observational analysis of histopathological specimens obtained from patients who underwent stapled hemorrhoidopexy using procedure for prolapse and hemorrhoids-03 circular staplers in the department of surgery of a tertiary care hospital in southern India was performed, and the correlation between the presence or absence of muscle fibers in the specimens and postoperative complications was evaluated. The patients were followed up for 12 months after the procedure.

Results In this study, 155 patients, including 54, 91, and 10 patients with Grade 2, Grade 3, and Grade 4 hemorrhoids, respectively, were included. Group A consisted of 19 patients with muscle fibers on the specimens, whereas Group B consisted of 139 patients without muscle fibers on the specimens. Early complications within 7 days after the procedure were as follows: 21 and 0.7% of the patients in Groups A and B, respectively, presented with postoperative pain with a visual analog scale score of more than 4; 47 and 6% of the patients in Groups A and B, respectively, presented with urinary retention; 26 and 2% of the patients in Groups A and B, respectively, presented with bleeding; and 21 and 2.9% of the patients in Groups A and B, respectively, presented with fecal urgency. A significant association was found between the presence of muscle fibers and early complications (p < 0.001). Late complications, such as proctalgia and bleeding, accounting for 36.8 and 6.6% in Groups A and B, respectively, were significantly associated with the presence of muscle fibers in histopathology (p < 0.001). Meanwhile, other late complications, such as incontinence, stenosis, and recurrence, exhibited no association (p > 0.05).

Conclusion The technique in taking purse-string sutures and the depth of the suture bite above the dentate line carry the utmost importance in preventing postoperative complications. Therefore, surgeons should refine their technique of appropriate depth to avoid incorporation of muscle fibers while executing the procedure.
Remote Supratentorial Recurrent Medulloblastoma: Case Study and Literature Review
Authors: Dominari Asimina , Antoniades Elias , Capiccelo Antonio , Hatzipantelis Emmanuil , Foroglou Nikolaos
Published: August 2022

Medulloblastomas comprise 10% of pediatric brain tumors. Subfrontal recurrence is uncommon and has been associated with prone positioning, inadequate irradiation of the cribriform plate area, and hydrocephalus management. We discuss the case report of an 8-year-old boy with subfrontal medulloblastoma recurrence. The literature was reviewed using terms such as “medulloblastoma,” “subfrontal recurrence,” and “child.” Forty-eight cases of subfrontal medulloblastoma recurrence were identified. The mean age at presentation was 12.3 years. Gross total resection was achieved in 44%, most patients received adjuvant radiation therapy, and approximately 25% received chemotherapy. The mean recurrence interval was 2.6 years. The mean number of recurrences per patient was 1.2 and the mean survival period was 3.3 years. Even in the case of meticulous resection and sufficient irradiation, recurrences may still occur. Our case indicates that resection of the recurrent lesion and repeat irradiation may benefit patients with satisfactory short-term results.
A Rare Case of Guillain–Barré Syndrome with Signs of Meningeal Irritation and Treatment-Related Fluctuations/Relapse
Authors: Singh Kushagra , Lohiya Sham , Chaudhary Richa , Lakra Mahaveer , Damke Sachin
Published: August 2022

Guillain–Barré Syndrome is an acute inflammatory demyelinating polyradiculoneuropathy that can present at any age. The presentation of Guillain–Barré syndrome may be variable as the classic symptoms of areflexia and flaccid paralysis may or may not be present. Here we reported a case of a 15-year-old male patient who presented with complaints of weakness in bilateral lower limbs with inability to sit along with slurred speech and drooling of saliva with positive meningeal signs like neck stiffness and Kernig's sign. His symptoms improved with immunoglobulin therapy. Five days later, the child again had pain and increased weakness with increased work of breathing for which repeat dose and course of immunoglobulins were given. As patients with signs of meningeal irritation may suggest other diseases such as meningitis, it is important to consider atypical cases of Guillain–Barré syndrome along with treatment-related fluctuations as observed in our patient.
Clinical Characteristics and Outcome of Patients with Multiple Intracranial Aneurysms from a University Hospital in Nepal
Authors: Sharma Mohan Raj , Kafle Prakash , Rajbhandari Binod , Pradhanang Amit Bahadur , Kumar Shrestha Dipendra , Sedain Gopal
Published: August 2022

Objective The risk factors, management strategies, and outcomes of patients with multiple intracranial aneurysms (MIAs) are different compared with that of patients with a single aneurysm. Data are scarce regarding patients with MIAs from developing countries. The objective of this study was to describe the clinical characteristics, management strategies, and outcomes of patients treated microsurgically from Nepal.

Methods The clinical records of patients confirmed to have MIAs and microsurgically clipped between July 2014 and December 2019 were retrospectively reviewed. Data on demographic and clinical characteristics, computed tomography findings, multiplicity and location of aneurysms, management strategies, and the 1-year outcome were abstracted and analyzed.

Results Two hundred cerebral aneurysms were microsurgically clipped in 170 consecutive patients during the study period. Twenty-six (13.0%) patients harbored 60 aneurysms. The mean age of the patients was 58.5 (43–73) years. Smoking and hypertension were found in 20 (76.9%) and 16 (61.5%) patients, respectively. The majority of patients [17 (65.4%)] were in good grades at presentation. Twenty-one patients had two aneurysms, four had three aneurysms, and one patient had five aneurysms. The middle cerebral artery was the commonest (20) followed by distal anterior cerebral artery (14) and anterior communicating artery (13) involved in multiplicity. A single-stage surgery was performed on 17 patients. Serial clipping was performed in six patients. In three patients, a single aneurysm on the contralateral side was left untreated for various reasons. The favorable outcome was achieved in 23 (88.5%) patients whereas three (11.5%) patients had an unfavorable outcome. One patient died.

Conclusion The demographic and clinical characteristics of patients in our series are comparable with those described in the published literature from other countries. With an individualized treatment strategy, an acceptable outcome can be achieved in the majority of the patients.
Risk Factors for Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage: A Tertiary Care Center Experience
Authors: Khan Muhammad Mohsin , Shaikh Nissar , Yousaf Zohaib , Sultan Hussain , Sadek George , Khan Adnan , Kamran Saadat , Ahmed Ayman Z. , Albanna Walid , Belkhair Sirajeddin , Ayyad Ali
Published: August 2022

Objectives Cerebral vasospasm in subarachnoid hemorrhage (SAH) is associated with high morbidity and mortality. There is a lack of consensus on the risk factors leading to cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage (aSAH). In this retrospective study, our objective was to determine the association of risk factors for cerebral vasospasm aSAH.

Methods A total of 259 charts of aSAH patients consecutively admitted to the surgical intensive care unit of Hamad General Hospital from January 2007 to December 2016 were reviewed and included. The patient's demographic data, including comorbidities like hypertension (HTN), was recorded. Variables of interest included measurements of the neurological deficit on admission, the severity of SAH, treatment modality, and the initial computerized tomography scan of the head for intraventricular hemorrhage, intracerebral hemorrhage, or hydrocephalus. Multivariate analysis and multiple logistic regression analyzed the relationship to identify the association of independent variables.

Results Out of the 259 patients, 34% (n = 87) suffered from cerebral vasospasm. The severity of SAH was associated with the development of cerebral vasospasm (p < 0.05). The presence of HTN and neurological deficits on admission were associated with an increased risk of cerebral vasospasm (p < 0.05, p < 0.01, respectively). Hydrocephalus requiring treatment using external ventricular drains decreased the risk of cerebral vasospasm (p < 0.05). Intraventricular and intracerebral hemorrhage were not associated with cerebral vasospasm (p = 0.25, p = 0.16). The endovascular treatment of cerebral aneurysms was associated with an increased risk of cerebral vasospasm (p < 0.05).

Conclusion Cerebral vasospasm is common among patients admitted with aSAH. It is significantly associated with the history of HTN, the neurological deficit on admission that corelates more strongly to the motor deficit on admission, the severity of hemorrhage (modified Fischer score), and endovascular treatment. External ventricular drainage was associated with a decrease in cerebral vasospasm. The present study's findings shed light on cerebral vasospasm's risk factors in the country and the region.
Acoustic radiation force on a rigid cylinder between two impedance boundaries in a viscous fluid
Authors: Liu Xinlei , Deng Zhaoyu , Ma Li , Liu Xiaozhou
Published: August 2022

Acoustofluidic technology combines acoustic and microfluidic technologies to realize particle manipulation in microchannels driven by acoustic waves, and the acoustic radiation force (ARF) with boundaries is important for particle manipulation in an acoustofluidic device. In the work reported here, the ARF on a free cylinder immersed in a viscous fluid with an incident plane wave between two impedance boundaries is derived analytically and calculated numerically. The influence of multiple scattering between the particle and the impedance boundaries is described by means of image theory, the finite-series method, and the translational addition theorem, and multiple scattering is included partly in image theory. The ARF on a free rigid cylinder in a viscous fluid is analyzed by numerical calculation, with consideration given to the effects of the distances from cylinder edge to boundaries, fluid viscosity, cylinder size, and boundary reflectivity. The results show that the interaction between the two boundaries and the cylinder makes the ARF change more violently with different frequencies, while increasing the viscosity can reduce the amplitude of the ARF in boundary space. This study provides a theoretical basis for particle manipulation by the ARF in acoustofluidics.
The Texas A&M University Hypervelocity Impact Laboratory: A modern aeroballistic range facility
Authors: Rogers Jacob A. , Bass Nathaniel , Mead Paul T. , Mote Aniket , Lukasik Gavin D. , Intardonato Matthew , Harrison Khari , Leaverton James D. , Kota Kalyan Raj , Wilkerson Justin W. , Reddy J. N. , Kulatilaka Waruna D. , Lacy Thomas E.
Published: August 2022

Novel engineering materials and structures are increasingly designed for use in severe environments involving extreme transient variations in temperature and loading rates, chemically reactive flows, and other conditions. The Texas A&M University Hypervelocity Impact Laboratory (HVIL) enables unique ultrahigh-rate materials characterization, testing, and modeling capabilities by tightly integrating expertise in high-rate materials behavior, computational and polymer chemistry, and multi-physics multiscale numerical algorithm development, validation, and implementation. The HVIL provides a high-throughput test bed for development and tailoring of novel materials and structures to mitigate hypervelocity impacts (HVIs). A conventional, 12.7 mm, smooth bore, two-stage light gas gun (2SLGG) is being used as the aeroballistic range launcher to accelerate single and simultaneously launched projectiles to velocities in the range 1.5–7.0 km/s. The aeroballistic range is combined with conventional and innovative experimental, diagnostic, and modeling capabilities to create a unique HVI and hypersonic test bed. Ultrahigh-speed imaging (10M fps), ultrahigh-speed schlieren imaging, multi-angle imaging, digital particle tracking, flash x-ray radiography, nondestructive/destructive inspection, optical and scanning electron microscopy, and other techniques are being used to characterize HVIs and study interactions between hypersonic projectiles and suspended aerosolized particles. Additionally, an overview of 65 2SLGG facilities operational worldwide since 1990 is provided, which is the most comprehensive survey published to date. The HVIL aims to (i) couple recent theoretical developments in shock physics with advances in numerical methods to perform HVI risk assessments of materials and structures, (ii) characterize environmental effects (water, ice, dust, etc.) on hypersonic vehicles, and (iii) address key high-rate materials and hypersonics research problems.
A unipolar compact nanosecond pulsed power supply with high power factor for dielectric barrier discharge applications
Authors: Tang Xiongmin , Jiang Tianhong , Fang Wenrui
Published: August 2022

A high voltage with a very short duration and fast rising time is beneficial to generate uniform and diffuse plasma in dielectric barrier discharge (DBD) loads, and a power supply with a high power factor (PF) can reduce the impact on the power grid. According to two requirements, a unipolar high voltage pulsed power supply with power factor correction (PFC) is proposed in this paper. The power supply consists of a unipolar pulse high voltage generating unit, a PFC unit, and a driving circuit. By introducing a feedback clamping diode and a reverse current blocking diode in a flyback converter, repetitive nanosecond pulses are generated in the unipolar pulse high voltage generating unit. Because a discontinuous current mode strategy is adopted in the PFC unit and the driving signal is shared by the two units, a compact structure of the power supply is achieved, and a high PF is obtained. To validate the proposed pulsed power supply, an experimental setup is built for a DBD excimer lamp. The results show that the proposed power supply has the capability of not only providing a unipolar nanosecond pulse high voltage for the DBD excimer lamp but also achieving PF close to 1 and total harmonic distortion of less than 24%.
Acceleration of imaging in atomic force microscopy working in sub-resonance tapping mode
Authors: Echols-Jones Piers , Messner William , Sokolov Igor
Published: August 2022

Sub-resonance tapping (SRT) mode of atomic force microscopy (AFM) enables researchers to image surfaces with well-controlled load forces and to collect maps of multiple physical properties of samples. The major bottleneck of this mode is a relatively low scan speed compared to other scanning modes. This paper presents a novel control algorithm that substantially improves the scanning speed over the standard SRT. We propose naming the new modality Trajectory Tracking SRT (TT-SRT). In contrast with the standard SRT control, TT-SRT uses the feedback within every single touch of the sample by the AFM probe. To demonstrate the advantage of TT-SRT, we conduct scans on a variety of samples with differing topologies, roughnesses, and mechanical properties. Each sample region is scanned with both standard SRT and TT-SRT at the same set of speeds. The control gains are tuned before each scan for maximum performance in each mode. Performance is evaluated by selecting a given level of image quality and finding the maximum speed that can be achieved by each algorithm. We find that with increased demand for data quality, the utility of TT-SRT becomes more apparent; for example, the speed of TT-SRT can be ten times faster or more than standard SRT for a reasonable expectation of data quality.
Field-free current-induced magnetization switching in GdFeCo: A competition between spin–orbit torques and Oersted fields
Authors: Bello Jean-Loïs , Quessab Yassine , Xu Jun-Wen , Vergès Maxime , Damas Héloïse , Petit-Watelot Sébastien , Rojas Sánchez Juan-Carlos , Hehn Michel , Kent Andrew D. , Mangin Stéphane
Published: August 2022

Switching of perpendicular magnetization via spin–orbit torque (SOT) is of particular interest in the development of non-volatile magnetic random access memory (MRAM) devices. We studied current-induced magnetization switching of Ir/GdFeCo/Cu/Pt heterostructures in a Hall cross geometry as a function of the in-plane applied magnetic field. Remarkably, magnetization switching is observed at zero applied field. This is shown to result from the competition between SOT, the Oersted field generated by the charge current, and the material's coercivity. Our results show a means of achieving zero-field switching that can impact the design of future spintronics devices, such as SOT-MRAM.
Octions: An E8 description of the Standard Model
Authors: Manogue Corinne A. , Dray Tevian , Wilson Robert A.
Published: August 2022

We interpret the elements of the exceptional Lie algebra e8(−24) as objects in the Standard Model, including lepton and quark spinors with the usual properties, the Standard Model Lie algebra su(3)⊕su(2)⊕u(1), and the Lorentz Lie algebra so(3,1). Our construction relies on identifying a complex structure on spinors and then working in the enveloping algebra. The resulting model naturally contains Grand Unified Theories based on SO(10) (Georgi), SU(5) (Georgi–Glashow), and SU(4) ×SU(2) ×SU(2) (Pati–Salam). We then briefly speculate on the role of the remaining elements of e8 and propose a mechanism leading to exactly three generations of particles.
Nanomolding of topological nanowires
Authors: Kiani Mehrdad T. , Cha Judy J.
Published: August 2022

For more than a decade since their experimental confirmation, topological materials have elicited interest from a wide variety of fields due to their unique symmetry-protected electronic states. Given a large number of theoretically predicted topological materials, new strategies are needed to fabricate topological nanomaterials in a high throughput manner in order to identify promising topological candidates for use in functional devices. In this Perspective, we discuss the use of nanomolding to fabricate topological nanowires; nanomolding is a scalable fabrication process in which a bulk polycrystalline feedstock is pressed into a nanostructured mold at an elevated temperature to form nanowires. Unlike traditional top-down and bottom-up fabrication methods, nanomolding requires minimal optimization of experimental parameters and can work on a wide variety of topological compounds, thus enabling high throughput fabrication of topological nanowires. The fabricated nanowires are single crystalline and defect-free and can have high aspect ratios greater than 1000. We also discuss how future developments in nanomolding can lead to new heterostructures, such as superconductor/semiconductor hybrid nanowires, and other nanomaterial shapes, such as plates or ribbons.
Modelling of track formation in nanocrystalline inclusions in Si3N4
Authors: Rymzhanov R. A. , Volkov A. E. , Zhalmagambetova A. , Zhumazhanova A. , Skuratov V. , Dauletbekova A. K. , Akilbekov A. T.
Published: August 2022

A multiscale modeling is applied to investigate structural changes caused by impacts of swift heavy ions in Si3N4 nanoclusters imbedded into amorphous and crystalline silicon nitride matrices. The approach combines the Monte Carlo code TREKIS describing the excitation kinetics of electronic and atomic subsystems and a classical molecular dynamics tracing subsequent relaxation of lattice atoms. Ion impacts in amorphous and crystalline Si3N4 result in formation of a cylindrical amorphous region of a reduced material density, surrounded by a shell with an increased density. The track diameter inside a nanosized inclusion in crystalline or amorphous matrices was found smaller than in surrounding materials, which can be explained by a heat confinement by grain boundaries.
Temporal-offset dual-comb vibrometer with picometer axial precision
Authors: Iwasaki A. , Nishikawa D. , Okano M. , Tateno S. , Yamanoi K. , Nozaki Y. , Watanabe S.
Published: August 2022

We demonstrate a dual-comb vibrometer where the pulses of one frequency-comb are split into pulse pairs. We introduce a delay between two pulses of each pulse pair in front of the sample, and after the corresponding two consecutive reflections at the vibrating sample surface, the initially introduced delay is canceled by a modified Sagnac geometry. The remaining phase difference between the two pulses corresponds to the change in the axial position of the surface during the two consecutive reflections. The Sagnac geometry reduces the effect of phase jitter since both pulses propagate through nearly the same optical path (in opposite directions), and spurious signals are eliminated by time gating. We determine the amplitude of surface vibration on a surface-acoustic-wave device with an axial precision of 4 pm. This technique enables the highly accurate determination of extremely small displacements.
Microfluidic synthesis as a new route to produce novel functional materials
Authors: Xie Xinying , Wang Yisu , Siu Sin-Yung , Chan Chiu-Wing , Zhu Yujiao , Zhang Xuming , Ge Jun , Ren Kangning
Published: August 2022

By geometrically constraining fluids into the sub-millimeter scale, microfluidics offers a physical environment largely different from the macroscopic world, as a result of the significantly enhanced surface effects. This environment is characterized by laminar flow and inertial particle behavior, short diffusion distance, and largely enhanced heat exchange. The recent two decades have witnessed the rapid advances of microfluidic technologies in various fields such as biotechnology; analytical science; and diagnostics; as well as physical, chemical, and biological research. On the other hand, one additional field is still emerging. With the advances in nanomaterial and soft matter research, there have been some reports of the advantages discovered during attempts to synthesize these materials on microfluidic chips. As the formation of nanomaterials and soft matters is sensitive to the environment where the building blocks are fed, the unique physical environment of microfluidics and the effectiveness in coupling with other force fields open up a lot of possibilities to form new products as compared to conventional bulk synthesis. This Perspective summarizes the recent progress in producing novel functional materials using microfluidics, such as generating particles with narrow and controlled size distribution, structured hybrid materials, and particles with new structures, completing reactions with a quicker rate and new reaction routes and enabling more effective and efficient control on reactions. Finally, the trend of future development in this field is also discussed.
From free-energy profiles to activation free energies
Authors: Dietschreit Johannes C. B. , Diestler Dennis J. , Hulm Andreas , Ochsenfeld Christian , Gómez-Bombarelli Rafael
Published: August 2022

Given a chemical reaction going from reactant (R) to the product (P) on a potential energy surface (PES) and a collective variable (CV) discriminating between R and P, we define the free-energy profile (FEP) as the logarithm of the marginal Boltzmann distribution of the CV. This FEP is not a true free energy. Nevertheless, it is common to treat the FEP as the “free-energy” analog of the minimum potential energy path and to take the activation free energy, ΔFRP‡, as the difference between the maximum at the transition state and the minimum at R. We show that this approximation can result in large errors. The FEP depends on the CV and is, therefore, not unique. For the same reaction, different discriminating CVs can yield different ΔFRP‡. We derive an exact expression for the activation free energy that avoids this ambiguity. We find ΔFRP‡ to be a combination of the probability of the system being in the reactant state, the probability density on the dividing surface, and the thermal de Broglie wavelength associated with the transition. We apply our formalism to simple analytic models and realistic chemical systems and show that the FEP-based approximation applies only at low temperatures for CVs with a small effective mass. Most chemical reactions occur on complex, high-dimensional PES that cannot be treated analytically and pose the added challenge of choosing a good CV. We study the influence of that choice and find that, while the reaction free energy is largely unaffected, ΔFRP‡ is quite sensitive.
Implement quantum tomography of polarization-entangled states via nondiffractive metasurfaces
Authors: Wang Zheng , Jiang Yue , Gao Ya-Jun , Fan Ren-Hao , Qi Dong-Xiang , Zhong Rui , Zhang Hu-Lin , Peng Ru-Wen , Wang Mu
Published: August 2022

Traditional optical elements, such as waveplates and polarization beam splitters, are essential for quantum state tomography (QST). Yet, their bulky size and heavy weight are prejudicial for miniaturizing quantum information systems. Here, we introduce nondiffractive silicon metasurfaces with high transmission efficiency to replace the traditional optical elements for QST of polarization-entangled states. Two identical silicon metasurfaces are employed, and each metasurface comprises four independent districts on a micrometer scale. The unit cell of each district consists of two silicon nanopillars with different geometrical sizes and orientation angles, and the interference of the scattered waves from the nanopillars leads to a single output beam from the district with a specific polarization state with a transmission efficiency above 92%. When the two-photon polarization-entangled state shines on different districts of two metasurfaces, each photon of the photon pair interacts with the local nanopillars within the district, and the two-photon state is projected onto 16 polarization bases for state reconstruction. We experimentally demonstrate the reconstruction of four input Bell states with high fidelities. This approach significantly reduces the number of conventional optical components in the QST process and is inspiring for advancing quantum information technology.
Tailoring skyrmion motion dynamics via magnetoelectric coupling: Toward highly energy-efficient and reliable non-volatile memory applications
Authors: Zhao Xuefeng , Wang Di , Zhang Hao , Liu Long , Lin Huai , Wang Ziwei , Zhang Xueying , Xie Changqing , Lin Weinan , Gao Nan , Pan Cheng , Xing Guozhong
Published: August 2022

Owing to the intriguing physical properties and significant spintronic applications, magnetic skyrmions have recently drawn intensive attention. Particularly, the skyrmion-based non-volatile memory (Sky-NVM) devices promise to be spintronic building blocks with high efficiency. However, tailoring Sky-NVM to achieve an energy-efficient and reliable operation in a synthetic, CMOS compatible, and magnetic-field-free integration is a challenging issue. Here, we report a new type of compact Sky-NVM with tailored skyrmion motion dynamics via in-plane strain gradient engineering. The skyrmion motion is merely driven by an in-plane electric field utilizing the magnetoelectric coupling effect, and the programmable switching is realized by gate biasing the potential barrier height via a voltage-controlled magnetic anisotropy. The proposed device is CMOS process compatible, and the comprehensive micromagnetic simulation results demonstrate that by applying a 0.3 V in-plane voltage combined with −0.17 V gate voltage, its write latency and the energy consumption reach 5.85 ns and 4.77 aJ/bit, respectively, superior to the state-of-the-art counterparts. Our work paves a new path toward ultra-low-power spintronic memory devices.
Prediction of the permeability of fibrous porous structures under the full flow regimes
Authors: Lai Bingzhu , Wang Zelin , Wang Hui , Bai Junqiang , Li Wenqiang , Ming Pingwen
Published: August 2022

Permeability of fibrous porous structures is a key material property for predicting the gas flow path during working conditions. A direct simulation Monte Carlo method is proposed to study the H2 gas flow in fibrous porous structures under different flow regimes of the molecular flow zone, transition zone, slip zone, and continuum zone. The effects of fibrous porous structural parameters such as porosity, fiber diameter, and variance of fiber diameter on the permeability are studied. Results show that the permeability of the continuous zone is in good agreement with that predicted by the semi-empirical formula, while the permeability of other flow regimes is larger than that predicted by the semi-empirical formula, and the deviation increases with the increase in the Knudsen number. The porosity, fiber diameter, and variance of fiber diameter have positive correlations with permeability under the full flow regimes. When the Knudsen number increases, the influence degree of porosity on the permeability gradually decreases, while the influence degree of the other parameters on the permeability increases. A new empirical formula considering the Knudsen number and structure characteristics is proposed to well predict the permeability of fibrous porous structures under the full flow regimes.
New phase diagram of miscible viscous fingering instabilities in porous media with dead-end pores
Authors: Yuan Qingwang , Ling Bowen , Aryana Saman A.
Published: August 2022

Classical miscible viscous fingering (VF) instability occurs when a less viscous fluid displaces a more viscous one in porous media with pores that are all well connected. Here, we investigate numerically how non-negligible dead-end pores, together with a limited mass transfer rate Da between the two pore types, affect fingering dynamics. We identify a new stabilizing mechanism induced by a reduction of effective viscosity contrast at an intermediate Da, which leads to a new phase diagram for VF instabilities in a Péclet number—Pe–Da parameter space and an elimination of fingers and tip-splitting at low and large values of Pe, respectively. A scaling analysis, along with an analysis of interfacial lengths, accurately predicts the boundary of the flow regimes and explains the origin of the new stabilizing mechanism.
Flow in a large wind field with multiple actuators in the presence of constant vorticity
Authors: Basu Sudipta Lal , Soodhalter Kirk M. , Fitzgerald Breiffni , Basu Biswajit
Published: August 2022

Study of wind farms is an area of active research. Researchers have proposed simplified wind farm models that define the wake structure in a wind farm and how they affect the performance of the wind turbines. Interestingly, these models do not take into account an important aspect of fluid flow, i.e., the fluid–structure interaction (FSI) between the turbines and the wind, which has an important role to play. This motivated researchers to implement numerical analysis tools to model the geometry of the wind turbines in computational fluid dynamics (CFD) based models of a wind farm in order to better understand the wake structure and study the performance of the wind farms. However, modeling the complex geometry of the blades and the turbines makes these models computationally expensive. In this paper, we propose an FSI methodology which can simplify the blade resolving CFD models and eliminate the requirement for modeling these complex geometries during preliminary engineering phase. As an example, we present simulations of up to three back-to-back wind turbines and compare the results with those obtained from wind engineering software, FLORIS. The proposed methodology demonstrates how the approach can be used to develop a relatively less computationally expensive wind farm model. The approach formulated in this paper follows an intermediate way between the analytical wind farm models and CFD models by introducing modifications to one of the most basic wind farm models (Jensen's model) and using it to develop a simplified CFD model using the decomposed immersed interface method strategy.
Physical origin of vortex stretching and twisting: Viscous or inertial forces
Authors: Lin L. M. , Wu Y. X.
Published: August 2022

In this paper, the physical origin of vortex stretching and twisting is theoretically investigated. The effects of inertial and viscous forces are mainly considered and discussed. Two key conditions, i.e., solid walls and three-dimensional (3D) disturbances, are adopted in three typical cases. Among them, the first two cases are straight and curved vortex lines at the initial time without any kind of disturbance. The third case is a straight vortex line at the initial time with introduced 3D natural disturbances. Through experimental observations, numerical simulations, and theoretical analysis in these cases, the first two cases illustrate that the straight or curved vortex lines are still straight or curved at the next time, respectively, regardless of whether solid walls are introduced. However, the third case clearly shows that once natural disturbances are introduced, the straight vortex lines near and at solid walls at the initial time are stretched and twisted mainly by viscous forces, instead of inertial forces, typically demonstrated by the 3D wake transition of a straight circular cylinder and the transition of the laminar boundary layer at a flat plate. Accordingly, based on definitions of generation and enhancement in vortex stretching and twisting, it is confirmed that the viscous forces with two key conditions are the generation mechanism, while the inertial forces alone are the enhancement mechanism.
Reservoir end wall effects on bivariate ion and fluid transport in micro/nano-nozzles for effective electroosmotic mixing
Authors: Majhi M. , Nayak A. K.
Published: August 2022

The aim of this study was to develop an efficient convection diffusion-based mathematical model for the species transport and mixing in different shaped (i.e., nozzle, diffuser, diffuser–nozzle, nozzle–diffuser) micro/nano-channels connected to large reservoirs. Both analytical and numerical studies are performed to illustrate the impact of inertial and contact angles for the generation of complex flow patterns due to different aspect ratio specified transformations. The hydrodynamics of the ion and fluid transport are analyzed through the Poisson–Nernst–Plank-based Navier–Stokes model subjected to specified system of forces endured by the reservoir fluids. The numerical results for pressure velocity correlations are obtained when the transport mechanism of the domain is changed from nozzle to diffuser. Mixing efficiency is evaluated for different geometric configurations and compared with a rectangular slit channel when the parallel reservoirs are connected. The role of Debye–Hückel parameter, conical angles or slope, and reservoir height/width on the transport of ions and enhancement of mixing are discussed. The mixing efficiency is found to attain a higher value after considering the reservoir connected to a nozzle without involving any hurdles or heterogeneous zeta potential along the channel wall. Closed-form analytical solutions of the electric potential are obtained through the linearized Poisson–Boltzmann model and further incorporated for the pressure evaluation. The axial and transverse velocities are evaluated from the modified Navier–Stokes equation including electric body force term and are validated with the experimental results. Effective nonlinear coupling responses of ion transport are found to be more pronounced in nozzle compared with diffuser resulting a higher mixing. Also, the solutions of velocity resulting in a low torque satisfy the equilibrium conditions and are optimized in terms of adversion of frictional factor and viscous dissipation resulting in an effective mixing. The findings manifest the species patterns with high accuracy and versatility, which could possibly help to handle the technical challenges associated with the design of pumpless actuated microfluidic devices.
Direct simulation Monte Carlo method based on ab initio potential: Recovery of transport coefficients of multi-component mixtures of noble gases
Authors: Sharipov Felix
Published: August 2022

The modeling of intermolecular collisions is the hardest and most time consuming part of the direct simulation Monte Carlo (DSMC) method. In order to reduce the computational cost of such modeling, lookup tables of deflection angle are calculated in the frame of quantum or classical theory of scattering. In the present work, the lookup tables for the noble gases, including helium-3, helium-4, neon, argon, krypton, and xenon, are calculated and provided in the supplementary material. The lookup tables for all possible mixtures of helium-4, neon, argon, and krypton are also provided. It is shown that the glancing collisions can be neglected reducing the computational cost without loss of numerical accuracy. Then, the lookup tables were revalidated via a recovery of the transport coefficients of multi-component mixtures, namely, viscosity, thermal conductivity, diffusion, and thermal diffusion. It is shown that the obtained tables recover the transport coefficients in a wide range of the temperature within the numerical error of the DSMC method.
Experimental study on flat plate skin friction control by porous media based on global fluorescent oil film measurement technology
Authors: Du Hai , Jiang Hao , Yang Zhangyi , Chen Shuo , Xia Haoyang , Zhang Wenxiao
Published: August 2022

Skin friction is a primary source of total aircraft drag. It is important, therefore, in science and engineering, to achieve drag reduction control in a boundary layer. In this paper, under the experimental conditions of Reθ = 5909 (x/c = 0.55) and with a zero-pressure gradient, the drag reduction control of a plate boundary layer in porous media is studied. The global skin friction of the plate is measured using fluorescent oil film test technology. The results show that, in contrast with the downstream frictional resistance coefficient of a flat plate that possesses a smooth surface, the coefficient for porous media reduced significantly. Also, the lower the pores per inch (PPI) of the porous media, the greater the drag reduction effect. Among the three porous media with different PPI, porous media with ten PPI has the best drag reduction effect. With increasing distance from the porous media, the drag reduction effect decreases gradually. Porous media significantly increase the slope of the logarithmic region of the velocity profile of the downstream turbulent boundary layer, the dimensionless wall velocity u+ moves upward, and the velocity pulsation in the logarithmic region increases so as to reduce skin friction.
Mining, capital and dispossession in post-apartheid South Africa
Authors: Zamchiya Phillan
Published: August 2022

Some Marxist political economists use accumulation by dispossession to explain processes in which natural resources are enclosed and their users dispossessed through extra-economic means. However, accumulation by dispossession takes an overly omnibus and materialistic approach in trying to cover a wide range of global processes. This article therefore distils accumulation by dispossession’s three central features of coercion, non-voluntary consent and corruption to enhance its local explanatory power of material and incorporeal dispossession in post-apartheid South Africa. This approach magnifies how a triumvirate of traditional leaders, state officials and Ivanplats platinum mine dispossessed people living on customary land in Limpopo, with detrimental effects.
Molecular-level evidence of force maintenance by smooth muscle myosin during LC20 dephosphorylation
Authors: Hammell Megan Jean , Kachmar Linda , Balassy Zsombor , IJpma Gijs , Lauzon Anne-Marie
Published: August 2022

Smooth muscle (SM) is found in most hollow organs of the body. Phasic SM, as found in the gut, contracts to propel content, whereas tonic SM, as found in most blood vessels, maintains tension. This force maintenance is referred to as the latch state and occurs at low levels of myosin activation (myosin light chain [LC20] phosphorylation). Molecular mechanisms have been proposed to explain the latch state but have been studied only at the whole-muscle level because of technological limitations. In the current study, an assay chamber was devised to allow injection of myosin light chain phosphatase (MLCP) during laser trap and in vitro motility assays, without creating bulk flow, to reproduce latch state conditions at the molecular level. Using the laser trap in a single-beam mode, an actin filament was brought in contact with several myosin molecules on a pedestal. Myosin pulled on the actin filament until a plateau force was reached, at which point, MLCP was injected. Force maintenance was observed during LC20 dephosphorylation, the level of which was assessed in a parallel in vitro motility assay performed in the same conditions. Force was maintained longer for myosin purified from tonic SM than from phasic SM. These data support the longstanding dogma of strong bonds caused by dephosphorylated, noncycling cross-bridges. Furthermore, MLCP injection in an in vitro motility mixture assay performed with SM and skeletal muscle myosin suggests that the maintenance of these strong bonds is possible only if no energy is provided by surrounding actively cycling myosin molecules.
Effect of Boundary Scattering on Magneto-Transport Performance in BN-Encapsulated Graphene
Authors: Zhu Lijun , Li Lin , Fan Xiaodong , Xie Zhongniu , Zeng Changgan
Published: August 2022

For conductors in the ballistic regime, electron-boundary scattering at the sample edge plays a dominant role in determining the transport performance, giving rise to many intriguing phenomena like low-field negative magnetoresistance effect. We systematically investigate the magneto-transport behaviors of BN-encapsulated graphene devices with narrow channel width W, wherein the bulk mean free path L
mfp can be very large and highly tunable. By comparing the magnetoresistance features and the amplitude of L
mfp in a large parameter space of temperature and carrier density, we reveal that the boundary-scattering-dominated negative magnetoresistance effect can still survive even when the ballistic ratio (L
mfp/W) is as low as 0.15. This striking value is much smaller than the expected value for achieving (quasi-) ballistic transport regime (L
mfp/W ≥ 1), and can be attributed to the ultra-low specularity of the sample edge of our graphene devices. These findings enrich our understanding of the effects of boundary scattering on channel transport, which is of vital importance for future designs of two-dimensional electronic devices with limited lateral sizes.
Flat FLRW Universe in logarithmic symmetric teleparallel gravity with observational constraints
Authors: Koussour M , Shekh S H , Hanin A , Sakhi Z , Bhoyer S R , Bennai M
Published: August 2022

In this paper, we investigate the homogeneous and isotropic flat Friedmann–Lemaître–Robertson–Walker Universe in the logarithmic form of

f

Q

gravity, where Q is the non-metricity scalar, specifically,

f

Q

=
α
+
β

log

Q

, where α and β are free model parameters. In this study, we consider a parametrization of the Hubble parameter as

H

z

=
η

(

z
+
1

)

−
γ

+
1

, where γ and η are model/free parameters which are constrained by an R
2-test from 57 points of the Hubble datasets in the redshift range 0.07 < z < 2.36. Further, we investigate the physical properties of the model. We analyze the energy conditions to check the compatibility of the model. We found the strong energy condition is violated for the logarithmic form of

f

Q

gravity due to the reality that the Universe in an accelerating phase. Finally, we discuss some important cosmological parameters in this context to compare our model with dark energy models such as jerk parameter and statefinder parameters.