bluuebunny/crossref_metadata_2025 huggingface dataset:
Insights into oscillator network dynamics using a phase-isostable framework
Authors: Nicks R. , Allen R. , Coombes S.
Published: January 2024

Networks of coupled nonlinear oscillators can display a wide range of emergent behaviors under the variation of the strength of the coupling. Network equations for pairs of coupled oscillators where the dynamics of each node is described by the evolution of its phase and slowest decaying isostable coordinate have previously been shown to capture bifurcations and dynamics of the network, which cannot be explained through standard phase reduction. An alternative framework using isostable coordinates to obtain higher-order phase reductions has also demonstrated a similar descriptive ability for two oscillators. In this work, we consider the phase-isostable network equations for an arbitrary but finite number of identical coupled oscillators, obtaining conditions required for the stability of phase-locked states including synchrony. For the mean-field complex Ginzburg–Landau equation where the solutions of the full system are known, we compare the accuracy of the phase-isostable network equations and higher-order phase reductions in capturing bifurcations of phase-locked states. We find the former to be the more accurate and, therefore, employ this to investigate the dynamics of globally linearly coupled networks of Morris–Lecar neuron models (both two and many nodes). We observe qualitative correspondence between results from numerical simulations of the full system and the phase-isostable description demonstrating that in both small and large networks, the phase-isostable framework is able to capture dynamics that the first-order phase description cannot.
Effect of isothermal annealing on formation of self-assembled nanostructures in manganese spinel ZnMnGaO4
Authors: Horibe Y. , Kawano I. , Tamaoka T. , Murakami Y.
Published: January 2024

The effects of isothermal annealing on the self-assembled nanostructures of spinel manganese oxide ZnMnGaO4 were investigated using transmission electron microscopy and x-ray diffraction. The checkerboard nanostructures and zigzag nanostructures (named “Sierra” nanostructures) coexisted owing to the chemical phase separation of Mn3+ and Ga3+ ions by isothermal annealing at 575 °C. It was observed that the checkerboard nanostructures were dominant in short-time annealing and that the volume fraction of the Sierra nanostructures became more prominent as the annealing period increase. The interdiffusion of Mn3+ and Ga3+ is indicated to play an important role in gaining the total energy of the system by the reduction in the local strain caused by the formation of nanostructures. These results provide further insights into the fabrication of distinct types of nanostructures in complex transition-metal compounds.
Effect of dislocations on carrier recombination and photoelectrochemical activity in polished and unpolished TiO2 and SrTiO3 crystals
Authors: Zhang Endong , Zhang Mingxin , Kato Masashi
Published: January 2024

TiO2 and SrTiO3 are stable and efficient materials for photoelectrochemical (PEC) water splitting. PEC activity is influenced by carrier recombination in crystals of these materials. In this study, we analyzed the effect of dislocations on carrier recombination in TiO2 and SrTiO3 using microwave photoconductive decay measurements on polished and unpolished faces. The apparent slow decay in the unpolished face implies that dislocations trap minority carriers. Based on the different dependences of the injected photon density and temperature, the recombination processes in the polished and unpolished faces differ. A high concentration of oxygen vacancies or hydroxyl in the unpolished face of SrTiO3 was observed by x-ray photoelectron spectroscopy, and dislocations in the unpolished faces of both materials were observed using transmission electron microscopy. Additionally, we found that the photocurrent duration in the unpolished faces was shorter than that in the polished faces for both TiO2 and SrTiO3, confirming that dislocations inhibited photoelectrochemical activity.
Remote focusing optical tweezers for 3D imaging
Authors: Zheng Ting Ting , Tian Yuan , Jiang Yong , Liu Chenguang , Hua Zijie
Published: January 2024

We present a remote focusing optical tweezer utilizing a 4f symmetrical optical system to compensate the high-order aberration during annular light refocusing. The position of the optical trap can be adjusted beyond the range of one hundred micrometers in the axial direction by means of tuning the position of the mirror placed in the focal region of the illumination objective lens. This optical tweezer can be combined with a sectioning microscope to realize three-dimensional (3D) imaging, e.g., a confocal microscope using a single water immersion objective lens. All optical elements are placed in one side of the sample, which is very useful for application in fields such as radiation biology, where radiation or magnetism disturbance must be introduced on the other side of the sample. In the experiment, a 10 µm diameter silicon dioxide microsphere and pollen cells immersed in the water are translated along the axis using the optical tweezer and, meanwhile, the sectioning images are obtained using the confocal microscope.
Single radio frequency bucket injection in the 88-Inch Cyclotron using a pulsed high voltage chopper
Authors: Covo M. Kireeff , Bloemhard P. , Benitez J. , Johnson M. , Todd D. , Duran J. Cruz , Ninemire B. , Phair L.
Published: January 2024

A single radio frequency bucket of the 88-Inch Cyclotron is filled using a fast chopper located in the axial line. The bucket then accelerates until it reaches the deflector, at which point, it is extracted as a train of bunches. This phenomenon can be attributed to the characteristic multi-turn extraction of the cyclotron and, by simplifying the complex dynamics of a cyclotron, corresponds to the conceptual transfer function of the cyclotron. The confirmation of the single radio frequency bucket injection was achieved by operating the cyclotron in the third harmonic mode and observing the absence of intermediate bunches during the multiple-bunch extraction.
Exact ideal magnetohydrodynamic Riemann solutions considering the strength of intermediate shocks
Authors: Xu Ke , Gao Zhenxun , Qian Zhansen , Lee Chun-Hian
Published: January 2024

Exact magnetohydrodynamic (MHD) Riemann solutions are the basis of constructing numerical schemes and benchmarks for verifying the schemes. However, non-strict hyperbolicity and nonconvexity of MHD equations contribute to the appearance of intermediate shocks, causing low efficiency of existing exact solvers and high dependence on iterative initials. Utilizing the magnetic critical Mach number proposed in this paper, all possible intermediate shocks are analyzed, parameterized, and categorized. Moreover, the possible wave structures on one side of contact discontinuity are revealed to have 25 cases, and initial conditions are classified into three categories according to the coplanar properties. Based on our findings, a new exact MHD Riemann solver is built. The robustness has been significantly improved after avoiding considerable judgments and the dependence on iterative initials. The analysis of the exact MHD Riemann solution is carried out by the characteristic properties of MHD shocks in the parameterization, and it is found that a solution space exists with the highest dimension of two dimensions under the given initial condition. It is proposed to adopt the intensities of 2 → 3 intermediate shocks as the free parameters of solution space, which can completely express the degree of solution space freedom. Finally, two examples that possess the solution space are used as verifications. The physical properties of MHD equations show that the dominant factor for the solution space is the unique characteristic property of 2 → 3 intermediate shock: the existence of an additional free parameter with tangential symmetry simultaneously.
Efficient formulation of multitime generalized quantum master equations: Taming the cost of simulating 2D spectra
Authors: Sayer Thomas , Montoya-Castillo Andrés
Published: January 2024

Modern 4-wave mixing spectroscopies are expensive to obtain experimentally and computationally. In certain cases, the unfavorable scaling of quantum dynamics problems can be improved using a generalized quantum master equation (GQME) approach. However, the inclusion of multiple (light–matter) interactions complicates the equation of motion and leads to seemingly unavoidable cubic scaling in time. In this paper, we present a formulation that greatly simplifies and reduces the computational cost of previous work that extended the GQME framework to treat arbitrary numbers of quantum measurements. Specifically, we remove the time derivatives of quantum correlation functions from the modified Mori–Nakajima–Zwanzig framework by switching to a discrete-convolution implementation inspired by the transfer tensor approach. We then demonstrate the method’s capabilities by simulating 2D electronic spectra for the excitation-energy-transfer dimer model. In our method, the resolution of data can be arbitrarily coarsened, especially along the t2 axis, which mirrors how the data are obtained experimentally. Even in a modest case, this demands O(103) fewer data points. We are further able to decompose the spectra into one-, two-, and three-time correlations, showing how and when the system enters a Markovian regime where further measurements are unnecessary to predict future spectra and the scaling becomes quadratic. This offers the ability to generate long-time spectra using only short-time data, enabling access to timescales previously beyond the reach of standard methodologies.
Polarization-insensitive, frequency- and amplitude-tunable transparent microwave absorber based on graphene metasurface
Authors: Wang Pan , Tao Hui , Han Wenlong , Zhang Canran , Xu Yijing , Wang Qilong
Published: January 2024

Transparent and flexible metamaterial absorbers can provide solutions for electromagnetic compatibility and electromagnetic radiation pollution. They also play key roles in platforms with optical windows that require low detectability and immunity to electromagnetic interference. Due to the lack of active adaptability to complex electromagnetic environments, early metamaterial absorbers need to be redesigned and manufactured once the application scenarios change. The new two-dimensional material graphene provides a practical technical approach for the realization of transparent tunable absorbers. In this work, we propose a polarization-insensitive dual-tunable microwave absorber based on graphene metasurface. By controlling two separate bias voltages applied to patterned graphene or continuous graphene, independent dynamic regulation of electromagnetic wave absorption frequency and amplitude is achieved. It also possesses the features of optical transparency and flexibility. The measurement results show that the absorption frequency can be shifted from 9.8 to 11.3 GHz, the peak absorption rate at each absorption frequency remains above 99.6%, and the reflection amplitude modulation can be achieved simultaneously at each absorption frequency. The proposed absorber integrates multiple modulation functions for electromagnetic waves, and the overall structure is optically transparent and flexible. Therefore, it can contribute to many practical wave absorbing applications.
Coherent excitation of spin waves in synthetic antiferromagnets by subpicosecond spin-transfer-torque
Authors: Xie Zong-Kai , Cai Jian-Wang , Cheng Zhao-Hua , He Wei
Published: January 2024

The subpicosecond spin-transfer-torque (STT) related to the laser-induced spin current is an effective approach to exciting spin waves in a noncollinear magnetic configuration. However, its validity on the excitation of spin waves in a synthetic antiferromagnet is still far from conclusive. Here, we investigate the impact of subpicosecond STT on the coherent excitation of spin waves in CoFeB/Ru/CoFeB. After pulsed-laser exposure, we observe both the precessional signals of acoustic mode and optical mode and find that their precession amplitudes are magnetic configuration-dependent. Not as the common explanation in the previous reports that the spin waves are triggered by the transient modulation of effective field, we attribute the initial stimulation of magnetization precession mainly to the subpicosecond STT. This mechanism is further confirmed by the field-dependent precession amplitudes. Our results pave a way for the practice of subpicosecond STT in the potential application at terahertz range.
Photo-induced electron paramagnetic resonance: A means to identify defects and the defect level throughout the bandgap of ultrawide bandgap semiconductors
Authors: Zvanut M. E. , Mollik Md Shafiqul Islam , Siford Mackenzie , Bhandari Suman
Published: January 2024

Ultrawide bandgap semiconductors (UWBGs) provide great promise for optical devices operating in the near to deep ultraviolet, and recently they have become a viable semiconducting material for high power electronics. From the power grid to electronic vehicles, the intention is to replace massively awkward components with the convenience of a solid state electronic “chip.” Unfortunately, the challenges faced by wide bandgap electronic materials, such as GaN and SiC, increase as the bandgap increases. A point defect, for example, can take on more charge states and energy configurations. This perspective describes a method to investigate the many charge states and their associated transitions—photo-induced electron paramagnetic resonance (photo-EPR) spectroscopy. Although not new to the study of defects in semiconductors, photo-EPR studies can probe the entire ultrawide bandgap given the appropriate light source for excitation. Examples provided here cover specific defects in UWBGs, AlN, and Ga2O3. The discussion also reminds us how the rapid pace of discovery surrounding this newest class of semiconductors is due, in part, to fundamental research studies of the past, some as far back as a century ago and some based on very different materials systems.
Effect of multi-parameter optimization of water-laser coupling device and nozzle geometry on the stability of water-guided laser beam
Authors: Wu Rui , Nie Songlin , Ji Hui , Wang Yueqi , Lin Luyan , Yin Fanglong
Published: January 2024

The stability of the water jet flow used in water-guided laser processing plays a crucial role in determining the quality of the processing process. The present study aims to investigate the effect of water-laser coupling device and nozzle geometry on the stable length of a water-guided laser beam. A numerical model is developed to analyze the internal flow field within the coupling device. Computational fluid dynamics (CFD) simulations are employed to examine how variations in cone nozzle's length-to-diameter ratio, divergence angle, nozzle aperture, and inlet pressure that affect the flow characteristics of water jet. Subsequently, the Latin Hypercube experimental design method is employed to establish parameter samples and construct a Kriging approximation model for the stable length of water-guided laser beam. The Multiple Island Genetic Algorithm (MIGA) is utilized for global optimization of the approximation model, while CFD methods are employed to analyze and validate the optimization results. Finally, experimental verification was conducted to determine the stable length of water-guided laser beam generated by the optimized cone nozzle structure. The research findings demonstrate that the optimized nozzle structure can compensate for approximately 21 mm in the stable distance of water-guided laser beam under the pressure of 5.0 MPa. This study provides valuable guidance for enhancing the performance and engineering applications of laser micro-jet processing technology.
What does cognitive screening reveal about early cognitive performance following endovascular clot retrieval and intravenous thrombolysis in acute ischaemic stroke?
Authors: Humphrey Sam , Pike Kerryn E. , Long Brian , Ma Henry , Bourke Robert , Byrne Danielle , Wright Bradley , Wong Dana
Published: January 2024

Background Little is known regarding cognitive outcomes following treatment with endovascular clot retrieval (ECR) and intravenous tissue plasminogen activator (t-PA). We aimed to determine if there were any differences on a measure of cognitive screening between patients treated with ECR, t-PA, and those who were managed conservatively. Methods The medical records of ischaemic stroke patients admitted to Monash Medical Centre between January 2019 and December 2019 were retrospectively reviewed. Information extracted from medical records included age, sex, National Institutes of Health Stroke Scale at presentation, location of occlusion, treatment type, medical history, and cognitive screening performance measured by the Montreal Cognitive Assessment (MoCA). Results Eighty-two patients met the inclusion criteria (mean age = 66.5 ± 13.9; 49 male, 33 female). Patients treated with ECR performed significantly better on the MoCA (n = 36, 24.1 ± 4.3) compared to those who were managed conservatively (n = 26, 20.7 ± 5.5). Performance for patients treated with t-PA (n = 20, 23.9 ± 3.5) fell between the ECR and conservative management groups, but they did not significantly differ from either. Conclusion Our retrospective chart review found that ischaemic stroke patients treated with ECR appear to perform better on cognitive screening compared to patients who are managed conservatively. We also found that patients treated with ECR and t-PA appear to have similar cognitive screening performances in the acute stages following ischaemic stroke, although this finding is likely to have been impacted by group differences in stroke characteristics and may reflect the possibility that the ECR group performed better than expected based on their stroke severity.
Emergence of threefold symmetric helical photocurrents in epitaxial low twinned Bi
2
Se
3
Authors: Connelly Blair C. , Taylor Patrick J. , de Coster George J.
Published: January 2024

We present evidence of a strong circular photon drag effect (PDE) in topological insulators (TIs) through the observation of helicity-dependent topological photocurrents with threefold rotational symmetry using THz spectroscopy in epitaxially-grown Bi
2
Se
3
with reduced crystallographic twinning. We establish how twinned domains introduce competing nonlinear optical (NLO) responses inherent to the crystal structure that obscure geometry-sensitive optical processes through the introduction of a spurious mirror symmetry. Minimizing the twinning defect reveals strong NLO response currents whose magnitude and direction depend on the alignment of the excitation to the crystal axes and follow the threefold rotational symmetry of the crystal. Notably, photocurrents arising from helical light reverse direction for left/right circular polarizations and maintain a strong azimuthal dependence—a result uniquely attributable to the circular PDE, where the photon momentum acts as an applied in-plane field stationary in the laboratory frame. Our results demonstrate new levels of control over the magnitude and direction of photocurrents in TIs and that the study of single-domain films is crucial to reveal hidden phenomena that couple topological order and crystal symmetries.
CLPB disaggregase dysfunction impacts the functional integrity of the proteolytic SPY complex
Authors: Baker Megan J. , Blau Kai Uwe , Anderson Alexander J. , Palmer Catherine S. , Fielden Laura F. , Crameri Jordan J. , Milenkovic Dusanka , Thorburn David R. , Frazier Ann E. , Langer Thomas , Stojanovski Diana
Published: January 2024

CLPB is a mitochondrial intermembrane space AAA+ domain–containing disaggregase. CLPB mutations are associated with 3-methylglutaconic aciduria and neutropenia; however, the molecular mechanism underscoring disease and the contribution of CLPB substrates to disease pathology remains unknown. Interactions between CLPB and mitochondrial quality control (QC) factors, including PARL and OPA1, have been reported, hinting at dysregulation of organelle QC in disease. Utilizing proteomic and biochemical approaches, we show a stress-specific aggregation phenotype in a CLPB-null environment and define the CLPB substrate profile. We illustrate an interplay between intermembrane space proteins including CLPB, HAX1, HTRA2, and the inner membrane quality control proteins (STOML2, PARL, YME1L1; SPY complex), with CLPB deficiency impeding SPY complex function by virtue of protein aggregation in the intermembrane space. We conclude that there is an interdependency of mitochondrial QC components at the intermembrane space/inner membrane interface, and perturbations to this network may underscore CLPB disease pathology.
Phosphatidylserine turns the gears of phospholipids in B cell lymphoma
Authors: Nakatsu Fubito , Kawasaki Asami
Published: January 2024

Phosphatidylserine levels and distribution are tightly controlled by dedicated enzymes at the ER and plasma membrane. Nakatsu and Kawasaki discuss new work by Aoki and colleagues (https://doi.org/10.1083/jcb.202212074), which reveals an acute reliance on phosphatidylserine synthesis in B cell lymphomas needed to prevent aberrant B cell receptor activation and ensuing apoptosis.
CD4+ T cells with latent HIV-1 have reduced proliferative responses to T cell receptor stimulation
Authors: Kufera Joshua T. , Armstrong Ciara , Wu Fengting , Singhal Anushka , Zhang Hao , Lai Jun , Wilkins Hannah N. , Simonetti Francesco R. , Siliciano Janet D. , Siliciano Robert F.
Published: January 2024

The latent reservoir for HIV-1 in resting CD4+ T cells persists despite antiretroviral therapy as a barrier to cure. The antigen-driven proliferation of infected cells is a major mechanism of reservoir persistence. However, activation through the T cell antigen receptor (TCR) can induce latent proviruses, leading to viral cytopathic effects and immune clearance. In single-cell studies, we show that, relative to uninfected cells or cells with a defective provirus, CD4+ T cells with an intact provirus have a profound proliferative defect in response to TCR stimulation. Virion production was observed in only 16.5% of cultures with an intact provirus, but proliferation was reduced even when no virion production was detected. Proliferation was inversely correlated with in vivo clone size. These results may reflect the effects of previous in vivo proliferation and do not support attempts to reduce the reservoir with antiproliferative agents, which may have greater effects on normal T cell responses.
The CCL-K11 ongoing key comparison. Final report for 2022
Authors: Matus M , Wallerand J-P , Fira R , Zechner G
Published: January 2024

Main text

Two lasers from two national metrological institutes (NMIs) were compared in the year 2022 as part of the CCL-K11 ongoing key comparison, initiated by the 13th meeting of the Comité Consultative des Longuers (CCL) in 2007. The absolute frequency of R(127) 11-5 (≈633 nm) transitions of molecular iodine was measured for these lasers following the technical protocol for CCL-K11. The results of these measurements are compiled in the present report. The comparison reports, as communicated by each participant, are included in the main document.

This document constitutes the twelfth final report for the ongoing key comparison CCL-K11.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Key comparison BIPM.RI(I)-K5 of the air-kerma standards of the CIEMAT, Spain and the BIPM in 137Cs gamma radiation
Authors: Kessler C , Roger P , Díaz N Cornejo
Published: January 2024

Main text

A first comparison of the standards for air kerma of the Laboratorio de Metrología de Radiaciones Ionizantes - Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (LMRI-CIEMAT), Spain, and of the Bureau International des Poids et Mesures (BIPM) was carried out in the 137Cs radiation beam using the radiation protection facility of the International Atomic Energy Agency (IAEA) in Seibersdorf, Austria, in September 2023. The comparison was done using the CIEMAT and the BIPM primary standards and a transfer instrument belonging to the CIEMAT. The direct comparison result, evaluated as a ratio of the CIEMAT and the BIPM standards for air kerma, is 0.9992 with a combined standard uncertainty of 2.2 parts in 103. The result for the indirect comparison is in agreement with the direct result at the level of 2.2 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database, to update the 2014 APMP comparison result.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
On the space of compact diamonds of Lorentzian length spaces
Authors: Barrera Waldemar , Montes de Oca Luis , Solis Didier A
Published: January 2024

In this work we introduce the taxicab and uniform products for Lorentzian pre-length spaces. We further use these concepts to endow the spaceD(R×TX)of causal diamonds with a Lorentzian length space structure, closely relating its causal properties with its geometry as a metric space furnished with its associated Hausdorff distance. Among the general results, we show that this space is geodesic and globally hyperbolic for a complete length space (X, d).
Unsolved problem of long-range interactions: dipolar spin-ice study
Authors: Yonetani Yoshiteru
Published: January 2024

Long-range interactions derive various strange phenomena. As illustrated by cutoff simulations of water, increasing cutoff length does not improve the simulation result necessarily; on the contrary, it makes the result worse. In the extreme situation, the structure of water transforms into a layer structure. In this study, to explore the underlying mechanism of this phenomenon, we performed Monte Carlo simulations on dipolar spins arranged on a pyrochlore spin-ice lattice. Like the water case, the present dipolar spin system also showed cutoff-induced dipole ordering and layer formation. The width of the layers depended on the cutoff length; and longer cutoff length led to a broader layer. These features are certainly consistent with the previous water case. This indicates that layer formation is the general behavior of dipolar systems whose interactions are truncated within a finite distance. The result is important for future exploration of the relationship between long-range interactions and resulting structures. In addition, it emphasizes the necessity of rigorous treatment of long-range interactions because increasing the cutoff length prevents convergence and provides an entirely different result from the rigorous Ewald calculation.
Resilient inequality constrained GNSS kinematic precise point positioning considering the terrain topography
Authors: Xu Huaqing , Zhang Zhetao , Wen Yuanlan , Li Yuan , Zeng Ping , Lu Tieding
Published: January 2024

In complex environments, signals are inevitably subject to phenomena such as reflection, refraction, diffraction, and obstruction, which result in significant unmodeled errors like colored noise, residual systematic errors, and other special outliers. Consequently, the achievement of high-precise and high-reliable global navigation satellite systems (GNSS) precise point positioning (PPP) is not a readily solvable problem in complex environments, especially in varying terrain topography. This paper proposed the resilient inequality constrained GNSS kinematic PPP method considering the terrain topography to improve the abnormal positioning results caused by unmodeled errors. Specifically, the proposed method is composed of the adaptive inequality constraint with dynamic penalty function and the timing-varying inequality considering the terrain topography. Two representative experiments including one set of designed data and three sets of daily measured data were conducted. The results show that the proposed method can improve the positioning results resulting from the unmodeled errors while preserving the trend of the original data. Typically, the proposed method decreases the standard deviations by 2.47, 0.25, and 1.46 cm in the U direction of the three real datasets, respectively. Consequently, the proposed method exhibits prospects in precision and reliability for complex environments.
Simulating the replication and entanglement of semi-rigid polymers in nano-injection moulding
Authors: Jiao Yuanqi , Ma Wenshi
Published: January 2024

Many polymers have been used to design polymer/metal composite structures with high bond strength through nano-moulding technology. However, whether high-molecular-weight polymers flow deeply into nanostructures and whether polymer entanglement hinders complete infiltration remain contentious issues in theoretical studies. In this study, the effects of the injection pressure, molecular weight of the semi-rigid polymer [polyphenylene sulphide (PPS)], and nanostructure size of the metal surface on the replication quality were investigated by molecular dynamics simulations. Increasing the injection pressure and polymer molecular weight increased the replication quality at practical temperatures. PPS with various chain lengths could completely infiltrate the nanopores. The nanostructure size of the metal surface was weakly negatively correlated with the filling rate, but it was substantially negatively correlated with the infiltration behaviour of the entire PPS chain. The reasons for infiltration of long-chain PPS and the steady evolution of the entanglement density were investigated. The steady entanglement density of PPS indicates that entanglement is not the main reason for the low filling rate. From the mobility of a single chain, the PPS chain flows into nanopores in a snake-like fashion. These results provide new insights to improve the adhesion strength between polymers and metals in nano-injection moulding.
Polydopamine nanoplatform with near infrared light and pH dual stimuli-responsive for chemo-photothermal cancer therapy
Authors: Tan He , Luo Zhong , Jia Mengran , Liu Zhuang , An Jinxia , Gao Hui
Published: January 2024

Photothermal agent accompanying with thermally responsive materials, displays well controlled drug release property, which is well-received as an outstanding design strategy for simultaneous photothermal/chemotherapy in cancer. Cyanine dye, as the prestigious photothermal agent has shown great potential due to its preeminent near-infrared absorbance and excellent thermal conversion efficiency. However, their inherent defect such as inferior photothermal stability, high leakage risk and poor therapy efficacy limit their further application in cancer therapy. Hence, a facile and universal strategy to make up these deficiencies is developed. Chemotherapeutic drug DOX and cyanine dye were loaded into polydopamine (PDA) nanoparticles. The PDA encapsulation dramatically improved the photothermal stability of cyanine dye. Attributed by the PDA structure feature, the thermo-sensitive small molecule glyamine (Gla) is introduced into the PDA surface to lessen leakage. The Gla can form a dense encapsulation layer on the dopamine surface through hydrogen bond. This newly fabricated Cyanine/DOX@PDA-Gla nanopaltform is characterized with NIR light/pH dual-responsive property, high NIR photothermal conversion performance and fluorescence guided chemo-photothermal therapy.
Switchable bi-functional metasurface for absorption and broadband polarization conversion in terahertz band using vanadium dioxide and photosensitive silicon
Authors: Luo Bing , Qi Yunping , Zhou Zihao , Shi Qiang , Wang Xiangxian
Published: January 2024

We proposed a bi-functional switchable metasurface based on vanadium dioxide (VO2) and photosensitive silicon. The metasurface functions as a transmissive polarization converter in its insulating state with asymmetric transmission characteristics. It attains a remarkable polarization conversion rate (PCR) surpassing 90% and a notable maximum asymmetric transmission (AT) parameter value of 0.73. This performance is observed within the frequency range from 4.31 to 7.86 THz. Dynamic regulation of PCR and AT can be achieved by adjusting the conductivity of photosensitive silicon. To illustrate the underlying factor behind the broadband polarization conversion, the surface current distribution is analyzed at 5.96 THz and 6.08 THz. On the other hand, when VO2 is in the metallic state, the metasurface transforms into a bidirectional absorber with near-perfect absorption in both illumination directions. Under forward incidence of terahertz waves, the absorption rates for the transverse electric and transverse magnetic waves are 99.3% at 3.54 THz and 93% at 3.56 THz, respectively. The physical mechanism of near-perfect absorption is explained using impedance matching theory and the electric field distribution. This research expands the applications of transmissive polarization converters within multifunctional metasurfaces, providing new avenues for their practical implementation.
Novel MoS2-decorated Cu2O hybrid nanoparticles for enhanced non-enzymatic electrochemical cholesterol detection
Authors: K M Janani , L Ashok Kumar , M Alagappan
Published: January 2024

Precise identification of cholesterol levels is crucial for the early diagnosis of cardiovascular risk factors. This paper presents a novel approach for cholesterol detection that circumvents the reliance on enzymatic processes. Leveraging the unique properties of advanced materials and electrochemical principles, our non-enzymatic approach demonstrates enhanced sensitivity, specificity, and limit of detection in cholesterol analysis. A non-enzymatic electrochemical biosensor for Cholesterol, employing a nanohybrid comprising Cu2O nanoparticles decorated with MoS2, is presented. The cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometry techniques were employed to investigate the electrochemical behaviour of the glassy carbon electrode modified with the Cu2O/MoS2 nanohybrid. The modified electrode exhibited an excellent sensitivity of 111.74 μA μM−1 cm−2 through the CV method and showcased a low detection limit of 2.18 μM and an expansive linear range spanning 0.1–180 μM when employing the DPV method. The electrode also showed good selectivity to various interfering components in 0.1 M NaOH and a satisfied stability of about 15 days at room temperature. The study demonstrates the potential for broader applications in clinical diagnostics and monitoring cardiovascular health, paving the way for a paradigm shift in cholesterol detection methodologies and offering a more efficient and cost-effective alternative to traditional enzymatic assays.
MRI non-rigid registration with tumor contraction correction for ablative margin assessment after microwave ablation of hepatocellular carcinomas
Authors: Dong Li-nan , Wang Shouchao , Dong Guoping , Kong Dexing , Liang Ping
Published: January 2024

Objective. This study aims to develop and assess a tumor contraction model, enhancing the precision of ablative margin (AM) evaluation after microwave ablation (MWA) treatment for hepatocellular carcinomas (HCCs). Approach. We utilize a probabilistic method called the coherent point drift algorithm to align pre-and post-ablation MRI images. Subsequently, a nonlinear regression method quantifies local tumor contraction induced by MWA, utilizing data from 47 HCC with viable ablated tumors in post-ablation MRI. After automatic non-rigid registration, correction for tumor contraction involves contracting the 3D contour of the warped tumor towards its center in all orientations. Main results. We evaluate the performance of our proposed method on 30 HCC patients who underwent MWA. The Dice similarity coefficient between the post-ablation liver and the warped pre-ablation livers is found to be 0.95 ± 0.01, with a mean corresponding distance between the corresponding landmarks measured at 3.25 ± 0.62 mm. Additionally, we conduct a comparative analysis of clinical outcomes assessed through MRI over a 3 month follow-up period, noting that the AM, as evaluated by our proposed method, accurately detects residual tumor after MWA. Significance. Our proposed method showcases a high level of accuracy in MRI liver registration and AM assessment following ablation treatment. It introduces a potentially approach for predicting incomplete ablations and gauging treatment success.
Assessment of valve regurgitation severity via contrastive learning and multi-view video integration
Authors: Kim Sekeun , Ren Hui , Charton Jerome , Hu Jiang , Maraboto Gonzalez Carola A , Khambhati Jay , Cheng Justin , DeFrancesco Jeena , Waheed Anam A , Marciniak Sylwia , Moura Filipe , Cardoso Rhanderson N , Lima Bruno B , McKinney Suzannah , Picard Michael H , Li Xiang , Li Quanzheng
Published: January 2024

Objective. This paper presents a novel approach for addressing the intricate task of diagnosing aortic valve regurgitation (AR), a valvular disease characterized by blood leakage due to incompetence of the valve closure. Conventional diagnostic techniques require detailed evaluations of multi-modal clinical data, frequently resulting in labor-intensive and time-consuming procedures that are vulnerable to varying subjective assessment of regurgitation severity. Approach. In our research, we introduce the multi-view video contrastive network, designed to leverage multiple color Doppler imaging inputs for multi-view video processing. We leverage supervised contrastive learning as a strategic approach to tackle class imbalance and enhance the effectiveness of our feature representation learning. Specifically, we introduce a contrastive learning framework to enhance representation learning within the embedding space through inter-patient and intra-patient contrastive loss terms. Main results. We conducted extensive experiments using an in-house dataset comprising 250 echocardiography video series. Our results exhibit a substantial improvement in diagnostic accuracy for AR compared to state-of-the-art methods in terms of accuracy by 9.60%, precision by 8.67%, recall by 9.01%, and F
1-score by 8.92%. These results emphasize the capacity of our approach to provide a more precise and efficient method for evaluating the severity of AR. Significance. The proposed model could quickly and accurately make decisions about the severity of AR, potentially serving as a useful prescreening tool.
Effect of nonlinearity, magnetic islands on turbulence and observation of electron energization, temperature anisotropy at Earth’s magnetopause (magnetosphere)
Authors: Upadhyay Manoj K , Uma R , Sharma R P
Published: January 2024

Space missions’ observations have shown that waves such as lower hybrid waves (LHWs), whistler waves, and kinetic Alfven waves play a vital role in magnetic reconnection, turbulence, and particle acceleration. This paper studies the effect of nonlinearity and the magnetic islands on lower hybrid turbulence and current sheets in Earth’s magnetopause region. The evolution of electromagnetic LHW has been studied with numerical model using pseudo-spectral method for spatial integration and finite difference method with modified predictor-corrector approach for temporal integration. We have considered both ion and electron dynamics and included electromagnetic and warm plasma effects in our model. The study outcomes reveal that both the nonlinear effects and magnetic islands are responsible for the evolution of LHWs and current sheets to a chaotic and turbulent state. We have also used the semi-analytical model to elaborate on the physics behind the localization. Finally, the nonlinear model with field perturbations (magnetic islands) is further used to elaborate on the electron energization and temperature anisotropy near reconnection regions. We have also discussed the relevance of model predictions in the context of the MMS mission observations at Earth’s magnetopause.
Dynamic response of nanosecond repetitively pulsed discharges to combustion dynamics: regime transitions driven by flame oscillations
Authors: Pavan Colin A , Shanbhogue Santosh J , Weibel Drew E , Gomez del Campo Felipe , Ghoniem Ahmed F , Guerra-Garcia Carmen
Published: January 2024

When using nanosecond repetitively pulsed discharges to actuate on dynamic combustion instabilities, the environment the discharge is created in is unsteady and changing on the timescale of the combustion processes. As a result, individual discharge pulses are triggered in a background gas that evolves at the timescale of combustion dynamics, and pulse-to-pulse variations may be observed during the instability cycle. Prior work has studied nanosecond pulsed discharges in pin-to-ring configurations used to control instabilities in lean-operating swirl-stabilized combustors, and observed variable discharge behavior. The focus of this work is on characterizing how the pulse-to-pulse discharge morphology, energy deposition, and actuation authority, evolve during the combustion instability cycle. This has important implications for designing effective plasma-assisted combustion control schemes. The discharge is observed in two distinct modes, a streamer corona and a nanosecond spark, with the occurrence of each regime directly linked to the phase of the combustor instability. Variation of pulse repetition frequency affects the total fraction of pulses in each mode, while variation of voltage affects the onset of the nanosecond spark mode. The transitions are described in terms of ratios of the relevant combustion and plasma timescales and the implications of this coupled interaction on the design of an effective control scheme is discussed.
3D simulations of positive streamers in air in a strong external magnetic field
Authors: Wang Zhen , Sun Anbang , Dujko Saša , Ebert Ute , Teunissen Jannis
Published: January 2024

We study how external magnetic fields from 0 to 40 T influence positive streamers in atmospheric pressure air, using 3D PIC-MCC (particle-in-cell, Monte Carlo collision) simulations. When a magnetic field
B
is applied perpendicular to the background electric field
E
, the streamers deflect towards the

+
B

and

−
B

directions which results in a branching into two main channels. With a stronger magnetic field the angle between the branches increases, and for the 40 T case the branches grow almost parallel to the magnetic field. Due to the

E
×
B

drift of electrons we also observe a streamer deviation in the opposite

−
E
×
B

direction, where the minus sign appears because positive streamers propagate opposite to the electron drift velocity. The deviation due to this

E
×
B

effect is smaller than the deviation parallel to
B
. In both cases of
B
perpendicular and parallel to
E
, the streamer radius decreases with the magnetic field strength. We relate our observations to the effects of electric and magnetic fields on electron transport and reaction coefficients.
The electronic and electromagnetic Dirac equations
Authors: Li Mingjie , Horsley S A R
Published: January 2024

Maxwell’s equations and the Dirac equation are the first-order differential relativistic wave equation for electromagnetic waves and electronic waves respectively. Hence, there is a notable similarity between these two wave equations, which has been widely researched since the Dirac equation was proposed. In this paper, we show that the Maxwell equations can be written in an exact form of the Dirac equation by representing the four Dirac operators with

8
×
8

matrices. Unlike the ordinary

4
×
4

Dirac equation, both spin–1/2 and spin–1 operators can be derived from the

8
×
8

Dirac equation, manifesting that the

8
×
8

Dirac equation is able to describe both electrons and photons. As a result of the restrictions that the electromagnetic wave is a transverse wave, the photon is a spin–1 particle. The four–current in the Maxwell equations and the mass in the electronic Dirac equation also force the electromagnetic field to transform differently to the electronic field. We use this

8
×
8

representation to find that the Zitterbewegung of the photon is actually the oscillatory part of the Poynting vector, often neglected upon time averaging.
Effect of doping with cobalt on the structure and optical properties of zinc oxide thin films prepared by sol-gel method
Authors: Khamis Fawzeia , Degig N M , Allaham Mohammad M , Mousa Marwan S
Published: January 2024

In this study, pure zinc oxide films doped with a cobalt percentage of 3% were prepared using Sol-Gel spin coating technique on a glass substrate at a temperature of 100 degrees Celsius. The structural and optical properties of these films have been studied. Structure properties are obtained by using x-ray diffraction (XRD) technique, they were carried out using a device of type (Panalytical X ‘Pert pro) with a target of type (Cu Kα) and a wavelength of (λ = 1.541 Ao). The diagnostic results showed that these films are polycrystalline and have a hexagonal structure with preferential orientation at (101). The Optical properties are concluded from absorption and transmission measurements, which are obtained by using the double beam UV-Visible1800 spectrophotometer in the wavelength (300–800) nm. It was found that the absorbance increases with increasing the doping percentage (1, 2, 3, and 4)mol%, while the transmittance is decreased. The optical properties also included the energy gap, the absorption coefficient, the reflectivity, the refractive index, the extinction coefficient, and the dielectric constant in its real and imaginary parts. It was found that the energy gap values decreased in the range 3.32–3.03 eV and the transmittance rate was 90% within the visible spectrum region.
Effects of individual heterogeneity on social contagions
Authors: Nian 年 Fu-Zhong 福忠 , Yang 杨 Yu 宇
Published: January 2024

Despite having significant effects on social contagions, individual heterogeneity has frequently been overlooked in earlier studies. To better understand the complexity of social contagions, a non-Markovian model incorporating heterogeneous social influence and adoption thresholds is introduced. For theoretical analysis, a generalized edge-based compartmental theory which considers the heterogeneities of social influence and adoption thresholds is developed. Focusing on the final adoption size, the critical propagation probability, and the phase transition type, social contagions for adoption thresholds that follow normal distributions with various standard deviations, follow various distributions, and correlate with degrees are investigated. When thresholds follow normal distributions, a larger standard deviation results in a larger final adoption size when the information propagation probability is relatively low. However, when the information propagation probability is relatively high, a larger standard deviation results in a smaller final adoption size. When thresholds follow various distributions, crossover phenomena in phase transition are observed when investigating the relationship of the final adoption size versus the average adoption threshold for some threshold distributions. When thresholds are correlated with degrees, similar crossover phenomena occur when investigating the relationship of the final adoption size versus the degree correlation index. Additionally, we find that increasing the heterogeneity of social influence suppresses the effects of adoption threshold heterogeneity on social contagions in three cases. Our theory predictions agree well with the simulation results.