bluuebunny/crossref_metadata_2025 huggingface dataset:
Stabilities and transition of a hypersonic boundary layer with three-dimensional distributed roughnesses
Authors: Wang Haopeng , Chen Xi , Tu Guohua , Wan Bingbing , Chen Jianqiang
Published: September 2024

Roughness surfaces likely present on high-speed flight vehicles due to ablation can greatly impact the laminar-turbulent transition process. In this work, effects of a randomly distributed roughness patch with roughness Reynolds number Rekk=474 on the stability and transition in a Mach 6.5 boundary-layer flow over a flat plate have been investigated via stability analyses and direct numerical simulation (DNS). The roughness patch induces several streamwise streaks downstream. The streaks slightly stabilize the Mack mode instability, yet sustain strongly unstable shear-layer modes, achieving a significantly larger integrated growth rate than the smooth case. The most amplified shear-layer mode extracts energy primarily through the spanwise velocity gradient and develops nonlinearly into hairpin vortices residing on the strongest low-speed streak. The hairpin vortices eventually contaminate the whole flowfield, leading to a fully turbulent state. We further assess the influences of wall-temperature ratio and the roughness geometry on the flowfield and the pertaining instability characteristics. The results reveal that the high wall-temperature ratio weakens the streak amplitudes and shear-layer instabilities; while randomly distributed roughness tends to induce larger-amplitude streaks than the regular counterpart with the same Rekk, the flowfield of the former one can even be more stable than the latter. We find that the spanwise gradient of streamwise velocity should also be considered along with the streak amplitude in determining the strength of shear-layer instabilities.
STP-based control of networked evolutionary games with multi-channel structure
Authors: Zhang Zhipeng , Jiang Xiaotong , Xia Chengyi
Published: September 2024

The channel delay in the game process has an important influence on its evolutionary dynamics. This paper aims to optimize the strategy game with general information delays, including the state delay in the previous work, and the control delay that is introduced for the first time to depict the time consumed by strategy propagation in reality. Specifically, the dynamics of networked evolutionary games is transformed into an algebraic form by use of the newly proposed semi-tensor product of matrices, which extends the ordinary matrix multiplication. Subsequently, according to the values of control and state delays, the strategy optimization problem can be divided into six different cases, and then via the constructed algebraic equation, we can obtain the sufficient and necessary conditions for the existence of the strategy optimization. Meanwhile, based on a reachable set method, the corresponding feedback controllers are further designed. Last, one illustrative example is taken to demonstrate the feasibility of our model. The results of this paper will be helpful to investigate the game-based control issues in the complex networked environment.
Semiclassical dynamics in Wigner phase space II: Nonadiabatic hybrid Wigner dynamics
Authors: Malpathak Shreyas , Ananth Nandini
Published: September 2024

We present an approximate semiclassical (SC) framework for mixed quantized dynamics in Wigner phase space in a two-part series. In the first article, we introduced the Adiabatic Hybrid Wigner Dynamics (AHWD) method that allows for a few important “system” degrees of freedom to be quantized using high-level double Herman–Kluk SC theory while describing the rest (the “bath”) using classical-limit linearized SC theory. In this second article, we extend our hybrid Wigner dynamics to nonadiabatic processes. The resulting Nonadiabatic Hybrid Wigner Dynamics (NHWD) has two variants that differ in the choice of degrees of freedom to be quantized. Specifically, we introduce NHWD(E) where only the electronic state variables are quantized and the NHWD(V) where both electronic state variables and a handful of strongly coupled nuclear modes are quantized. We show that while NHWD(E) proves accurate for a wide range of scattering models and spin-boson models, systems where a few nuclear modes are strongly coupled to electronic states require NHWD(V) to accurately capture the long-time dynamics. Taken together, we show that AHWD and NHWD represent a new framework for SC simulations of high-dimensional systems with significant quantum effects.
Investigation of flow-induced vibration and energy extraction of a bluff body with different immersed depths and cross section shapes
Authors: Song Tian , Ding Lin , He Haoyu , Ran Jingyu
Published: September 2024

This paper investigated the effects of immersed depth and cross section shape on flow-induced vibration (FIV) response and power harvesting performance by experiment and numerical simulation. The experiment was carried out in a recirculating water channel. Three cross section shapes were considered: circular, square, and equilateral triangle. The reduced velocity spans from 3 to 15. The range of immersed depth ratio H* = Hi/D is from 2 to 8, where Hi is the immersed depth, D is the reference length of the cylinders, and the case of H* = 8 is fully immersed in water. The results show that vortex-induced vibration response in the crossflow direction of a circular cylinder is observed when the immersed depth ratio reaches H* ≥ 6. Out of the cylinders examined, the triangular cylinder exhibits the strongest amplitude response. The maximum amplitude in the crossflow direction of the triangular cylinder, reaching 2.38D, is obtained at H* = 8 and U* = 15. The energy output performance of the FIV energy harvesting system is the most superior when utilizing triangular cylinders. Importantly, when the triangular cylinder is completely immersed in water and the reduced velocity surpasses 10, it has the capability to produce an output power that exceeds 1200 μW.
Effect of width and thickness on propagating spin waves in permalloy microstripe waveguides
Authors: Devapriya M. S. , Aditya Nair S. , Kuchibhotla Mahathi , Adeyeye Adekunle Olusola , Haldar Arabinda
Published: September 2024

We report the effect of thickness and width on the spin wave transport and dispersion characteristics of permalloy (Py) microstripes using analytical calculations and experiments. Py waveguides with widths ranging from 2 to 4 μm were fabricated for two different thicknesses: 5 and 20 nm. Our results show a notable increase in the group velocity of spin waves with greater thickness, showing a fourfold rise as the thickness increases. Additionally, the accessible frequency range expands from 0.6 to 2.5 GHz as the thickness increases. We find that the spin wave mode frequency is affected by both thickness and width, with a frequency shift of approximately 0.2 GHz observed when the width increases from 2 to 4 μm. Moreover, spin waves decay more rapidly in thinner films, with the decay length of 20 nm-thick waveguides being four times longer than that of 5 nm-thick waveguides. Thicker and wider waveguides provide a longer decay length, facilitating the transmission of information over longer distances without significant energy loss. Our study offers an understanding of the spin wave propagation in microstrip waveguides and its potential in the development of future magnonic devices.
Comparative analysis of corner separation controlled by steady jets and oscillating jets on a compressor cascade
Authors: Yang Zonghao , Liu Bo , Mao Xiaochen , Wang Hejian , Jiao Yingchen
Published: September 2024

To mitigate corner separation in compressor cascades, this study compares the control effects of single oscillating jets (SOJ), arrayed oscillating jets (AOJ), single steady jets (SSJ), arrayed steady jets (ASJ), and full-span steady jets (FSJ) configured on the blade surface. The results indicate that steady jet schemes can only reduce the overall total pressure loss within a limited range of incidence angles. In contrast, oscillating jet schemes can reduce the overall total pressure loss over a wider range of incidence angles and offer better active control effects, with a maximum loss reduction of about 40% in the AOJ scheme. Additionally, all jet schemes can reduce the vorticity of the passage vortices and concentrated shedding vortices in the corner region through the jet momentum injection effect, thereby reducing corner losses. However, in SSJ and SOJ schemes, the reduction of corner separation eventually results in higher blade losses. Furthermore, in ASJ, AOJ, and FSJ schemes, the increased shear interaction between the jet and mainstream raises the trailing-edge shedding vortex's structure size and vorticity, which increases blade mixing losses. Finally, the cascade flow field in steady jet schemes shows almost no significant pulsation characteristics. In contrast, the flow field in oscillating jet schemes exhibits higher-frequency pulsations at the excitation frequency, and the two-norms and growth rates of the main modes through dynamic mode decomposition in the corner region significantly increase, indicating a more effective jet momentum injection effect.
Lattice Boltzmann method computation of the incompressible flow past an impulsively started cylinder
Authors: Barrero-Gil A. , Velazquez A.
Published: September 2024

Computation of impulsively started flows presents difficulties associated with the presence of a singularity at time equal to zero. When using the lattice Boltzmann method, the standard practice is to start the computation from a potential flow field that is not part of the solution. A different approach to the problem is presented in this article where three new criteria for the selection of computational parameters in highly unsteady flow environments are presented. These criteria, which do not overrule the conventional one that sets limits to the computational Mach number, are based on fluid physics considerations. They represent additional constrains related to (a) the distance traveled by sound waves at early times, (b) the importance of viscous length during the onset of impulsive motion, and (c) the presence of spurious reflected pressure waves at the beginning of computations. The proposed methodology was tested in the case of an impulsively started cylinder, and the results were compared to those of analytical, numerical, and experimental nature published in specialized literature. It is intended that this study facilitates the computation of highly unsteady flows for researchers who use the lattice Boltzmann method.
Noncritical, temperature-tuned, narrowband, intracavity-pumped CdSe OPO
Authors: Wang Li , Chen Weidong , Ni Youbao , Wang Zhenyou , Pasiskevicius Valdas , Divliansky Ivan B. , Moelster Kjell M. , Mhibik Oussama , Wu Haixin , Jiang Haihe , Zukauskas Andrius , Petrov Valentin
Published: September 2024

We report on a cascade nanosecond CdSe optical parametric oscillator with an output energy of 0.54 mJ at 100 Hz, temperature tuning within 9245–9285 nm, and a narrow (∼6 cm−1) spectral width achieved by a volume Bragg grating acting on the first stage. The CdSe crystal is pumped intracavity by the signal wave from the PPKTP-based first stage, and both stages operate under noncritical phase-matching conditions. The simple, compact, and robust setup produced the highest overall conversion efficiency for an all-solid-state laser system based on CdSe with 1-μm pumping, and the corresponding quantum conversion efficiency exceeded 13%.
Ultrahigh electromechanical response in (K,Na)NbO3-based lead-free textured piezoceramics
Authors: Liu Yang , Bian Lang , Zhang Rui , Fan Jinhui , Huo Da , Shen Bingzhong , Huang Houbing , Shi Xiaoming , Wang Dawei , Yao Kui
Published: September 2024

The progress of next-generation electromechanical devices is substantially reliant upon achieving high electromechanical coupling performance in piezoelectric materials. Here, a local stress regulation strategy is introduced to significantly enhance the overall electromechanical response of lead-free piezoceramics. A remarkable large piezoelectric coefficient (d33) of ∼800 pC N−1 and longitudinal electromechanical coupling factor (k33) of 88% are obtained in (K,Na)NbO3 (KNN)-based textured piezoceramics. From both experimental examinations and theoretical simulation, including phase-field analyses, it is found that the improved piezoelectric performance primarily stems from the stress-induced elastic field aligned with the preferred crystallographic orientation, which constrains the domain size, resulting in nanoscale short-range ordered domain structures. Such structures facilitate the flexible rotation of electric dipoles within coexisting phases due to flattened free energy distribution, thereby leading to the exceptionally large piezoelectric response. This understanding provides valuable guidance for the design of novel lead-free piezoceramics with excellent piezoelectric performance.
Transition characteristics, fluctuation evolution, and the role of coherent mode in electron cyclotron resonance heated low to high mode transition in KSTAR
Authors: Jhang Hogun , Choi Minjun J , Kim Hyun-Seok
Published: September 2024

An experimental study is conducted on macro- and microscopic characteristics of low to high (LH) transition acquired by electron cyclotron resonance heating (ECRH) in KSTAR. A scan of pre-transition density demonstrates the existence of the characteristic minimum density, which requires minimum power to make LH transition. The minimum density in KSTAR shows a tendency to be lower than that evaluated from an empirical scaling law proposed by Ryter et al. [Nucl. Fusion 54, 083003 (2014)]. A comprehensive study of the evolution of low wavenumber electron temperature fluctuations is carried out using electron cyclotron emission imaging diagnostics. An analysis of the fluctuation amplitude in L-mode in terms of the electron collisionality and the electron temperature scaling length suggests that the dissipative trapped electron mode is likely to be a dominant instability before the LH transition. The fluctuation amplitude reduces first as the transition starts. A coherent mode that chirps down from 60 to 20 kHz emerges when the transition further develops. This coherent mode is then shown to revive turbulence that has been reduced significantly during the initial stage of the LH transition. The revival of turbulence could be a possible origin of the absence of the large edge localized mode when the coherent mode is persistent in ECRH-induced H-mode plasmas.
Effect of nanoscale nuclei on the dynamics of laser-induced cavitation
Authors: Li Mingbo , Li Yuhan , Gao Yawen , Sun Chao , Wang Benlong
Published: September 2024

Cavitation inception generally originates from gaseous nuclei in a liquid, either as an air pocket on a solid wall or freely suspended gaseous contaminants. In this work, the impact of nanoscale nuclei, typically around 100 nm in diameter, on laser-induced cavitation is explored. The experimental results indicate that the presence of these nanoscale entities can readily trigger multiple optical breakdowns, resulting in a spark column with essentially discrete character and a train of primary cavitation bubbles nucleating along the laser-focusing path. The investigation further reveals a nuanced relationship between laser pulse energy and cavitation bubble size, moderated by nanoscale nuclei concentration, which ultimately caps the maximal bubble size to approximately 300 μm. The study also delves into the aftermath of initial breakdowns, elucidating the genesis of secondary cavitation through the expansion of both pre-existing and laser-excited nanoscale gaseous nuclei, facilitated by a transient negative pressure field that is formed by the reflection of shock waves on adjacent bubbles' surface. Molecular dynamics simulations demonstrate the scenario at a smaller scale and reveal that the presence of nanobubbles is more conducive to the rupture of the surrounding water under the action of tension waves to generate cavities. This work may lay a foundational framework for future explorations aimed at decrypting the thresholds of cavitation inception, thereby enriching the academic discourse on the control and manipulation of cavitation phenomena within liquid mediums.
Achievement and mechanism of large-scale color tunable OLEDs based on interfacial charge transfer complexes with dual donors
Authors: Shen Zhongtao , Lü Zhaoyue , Chen Zhehao , Wang Junling , Mu Haichuan
Published: September 2024

Color tunable organic light-emitting diodes have intrigued many application fields, such as smart lighting and information encryption. In this study, we propose a simple structure based on interfacial charge transfer complexes (CTCs) with double donors and single acceptors for achieving color tunability. Through embedding a second donor between the primary donor and the acceptor, the emission of devices can be well-tuned by simply controlling the applied voltage. The calculated frontier molecular orbitals of constituted monomers and heterodimers via density function theory confirm the formation of CTCs between the donors and acceptor. Importantly, the highest occupied molecular orbital level and charge carrier mobility of the second donor are crucial to realize widely adjustable spectra with the voltage. With this strategy, the device incorporating 1,3-di(9H-carbazol-9-yl)benzene as the second donor and 4,4′,4″-tris[(3-methylphenyl)phenylamino] triphenylamine as the primary donor exhibits the largest color shift. The CIE coordinates span from (0.52, 0.46) at 4 V to (0.29, 0.26) at 10 V. These findings shed light on the fact that the double-donor-strategy is feasible for fulfilling large-scale color tunability of CTC-based organic light-emitting diodes and is beneficial to simplify the fabrication process.
Analytical solution for lateral depth-averaged velocity distributions in meandering compound channels with vegetated floodplains
Authors: Yang Yongpeng , Sun Bin , Li Zhiwei , Wang Feifei , Li Huaxiang , Li Heng
Published: September 2024

Meandering compound channels, which are the most common platform acquired by natural rivers, are typically equipped with vegetated floodplains that exhibit complex hydraulic characteristics and sediment transport processes. Given that studying depth-averaged streamwise velocity is the foundation for determining flood discharge performance and sediment carrying capacity, this paper presents an analytical solution to forecast the lateral velocity distribution in meandering compound channels with vegetated floodplains. The analytical model, which incorporates the effects of bed friction, vegetation-induced drag force, transverse shear turbulence, and secondary flows, is derived from the longitudinal depth-integrated Navier–Stokes equation and the continuity equation by assuming the secondary current term and additional Reynolds stress term to be laterally linear. The proposed model is then successfully applied to curved compound channels with different vegetated floodplains reported in the literature. The satisfactory agreement between predicted and experimental results of velocity distribution validates the effectiveness of the analytical model. Thereafter, the impact of varying characteristic parameters on the lateral profile of the velocity is discussed and analyzed by applying the validated analytical model. Results indicate that the secondary current coefficients and the dimensionless eddy viscosity exert more pronounced influences on the velocity distribution than the parameters associated with the vegetation-triggered drag force. Furthermore, it is found that the sizes and signs of the secondary current coefficients are contingent upon the intensities and rotational directions of the secondary flow cells. The presented model can be employed as an alternative methodology to gain insight into the flow characteristics of curved rivers with vegetated floodplains.
Spin conductances and magnetization production in chiral molecular junctions
Authors: Korytár Richard , van Ruitenbeek Jan M. , Evers Ferdinand
Published: September 2024

Motivated by experimental reports on chirality induced spin selectivity, we investigate a minimal model that allows us to calculate the charge and spin conductances through helical molecules analytically. The spin–orbit interaction is assumed to be non-vanishing on the molecule and negligible in the reservoirs (leads). The band structure of the molecule features four helical modes with spin-momentum locking that are analogous of edge-currents in the quantum spin Hall effect. While charge is conserved and therefore the charge current is independent of where it is measured—reservoirs or molecule—our detailed calculations reveal that the spin currents in the left and right leads are equal in magnitudes but with opposite signs (in linear response). We predict that transport currents flowing through helical molecules are accompanied by a spin accumulation in the contact region with the same magnetization direction for source and drain. Furthermore, we predict that the spin-conductance can be extracted directly from measuring the (quasi-static) spin accumulation—rather than the spin current itself, which is very challenging to obtain experimentally.
Motion characteristics of a single bubble in liquid metal under a streamwise magnetic field
Authors: Gou Haoyang , Lyu Ze , Ni Ming-Jiu , Yao Zhaohui
Published: September 2024

The three-dimensional motion trajectories of bubbles in liquid metal have been extensively measured under a horizontal magnetic field (HMF) using ultrasonic phased array technology. This study focuses on the case of a streamwise magnetic field (SMF). Experimental results show that the anisotropy of bubble oscillation in HMFs is not observed in the SMF. Under a weak SMF, single bubbles exhibit zigzag oscillation motion whose axis is along the streamwise direction. The oscillation frequency and amplitude decrease as the SMF intensity increases. As the SMF becomes stronger, the bubble suddenly begins to exhibit low-frequency oblique oscillations, the main axis of which deviates from the streamwise direction. Further increases in the SMF intensity produce an oblique straight-line motion, with the oblique oscillations suppressed by the magnetic field. Under the SMF, the terminal velocity of the bubbles initially increases when the magnetic interaction parameter is N<1, with the attenuation of the oscillation frequency being the dominant cause. However, the magnitude of velocity growth under the SMF is smaller than that in the case of an HMF. When N>1, the bubble terminal velocity steadily decreases and exhibits a similar trend to that under the HMF, along with an increase in the drag coefficient.
Thermal performance analysis and prediction of a circumferential serpentine tube for high-power motor cooling
Authors: Gao Zhigang , Liu Hang , Bai Junhua , Zhang Haotian , Wang Zhiqiang , Wang Lin
Published: September 2024

The servo motor in the actuator of flight vehicles suffers both a high-power loss and a harsh thermal environment, which lead to a risk of overheating failure. To address this issue, the liquid cooling device is employed on the flight vehicle to remove heat from the motor, using the onboard cryogenic fuel (supercritical methane, S-CH4) as the coolant. To improve the applicability and versatility, a circumferential serpentine tube (CST) encircled the motor as the cooling jacket is proposed. This configuration has a compact structure as well as a large heat exchange area, and the inlet and outlet of the cooling tube locate adjacently, which is convenient to arrange and install the coolant pipeline. With this in mind, a three-dimensional numerical model of CST is established based on the shear stress transport k–ω turbulent model, and the flow and heat transfer of S-CH4 in CST are explored. The effects of operating parameters, such as pressure, heat flux, and mass flux, on the heat transfer are analyzed. The results present that the heat dissipation performance of motor is improved significantly, owing to the combined effect of the thermophysical properties of S-CH4 and the geometric structure of CST. Furthermore, the heat transfer prediction of CST is investigated by comparing various heat transfer correlations, and an improved one is proposed furtherly based on the Ornatsky's correlation owing to its better prediction relatively. Thereinto, the geometric parameters of CST, the thermophysical properties of supercritical coolant, and the flow regime of convection are considered. The average error is 8.66% under various operating conditions and improved by 40.73% compared with that of the Ornatsky's correlation, indicating a superior prediction accuracy.
Deep learning models map rapid plant species changes from citizen science and remote sensing data
Authors: Gillespie Lauren E. , Ruffley Megan , Exposito-Alonso Moises
Published: September 2024

Anthropogenic habitat destruction and climate change are reshaping the geographic distribution of plants worldwide. However, we are still unable to map species shifts at high spatial, temporal, and taxonomic resolution. Here, we develop a deep learning model trained using remote sensing images from California paired with half a million citizen science observations that can map the distribution of over 2,000 plant species. Our model—Deepbiosphere—not only outperforms many common species distribution modeling approaches (AUC 0.95 vs. 0.88) but can map species at up to a few meters resolution and finely delineate plant communities with high accuracy, including the pristine and clear-cut forests of Redwood National Park. These fine-scale predictions can further be used to map the intensity of habitat fragmentation and sharp ecosystem transitions across human-altered landscapes. In addition, from frequent collections of remote sensing data,Deepbiospherecan detect the rapid effects of severe wildfire on plant community composition across a 2-y time period. These findings demonstrate that integrating public earth observations and citizen science with deep learning can pave the way toward automated systems for monitoring biodiversity change in real-time worldwide.
Mechanical confinement prevents ectopic platelet release
Authors: Guinard Ines , Brassard-Jollive Noémie , Ruch Laurie , Weber Josiane , Eckly Anita , Boscher Julie , Léon Catherine
Published: September 2024

Blood platelets are produced by megakaryocytes (MKs), their parent cells, which are in the bone marrow. Once mature, MK pierces through the sinusoid vessel, and the initial protrusion further elongates as proplatelet or buds to release platelets. The mechanisms controlling the decision to initiate proplatelet and platelet formation are unknown. Here, we show that the mechanical properties of the microenvironment prevent proplatelet and platelet release in the marrow stroma while allowing this process in the bloodstream. Loss of marrow confinement following myelosuppression led to inappropriate proplatelet and platelet release into the extravascular space. We further used an inert viscoelastic hydrogel to evaluate the impact of compressive stress. Transcriptional analysis showed that culture in three-dimensional gel induced upregulation of genes related to the Rho-GTPase pathway. We found higher Rho-GTPase activation, myosin light chain phosphorylation and F-actin under mechanical constraints while proplatelet formation was inhibited. The use of latrunculin-A to decrease F-actin promoted microtubule-dependent budding and proplatelet extension inside the gel. Additionally, ex vivo exposure of intact bone marrow to latrunculin-A triggered proplatelet extensions in the interstitial space. In vivo, this confinement-mediated high intracellular tension is responsible for the formation of the peripheral zone, a unique actin-rich structure. Cytoskeleton reorganization induces the disappearance of the peripheral zone upon reaching a liquid milieu to facilitate proplatelet and platelet formation. Hence, our data provide insight into the mechanisms preventing ectopic platelet release in the marrow stroma. Identifying such pathways is especially important for understanding pathologies altering marrow mechanics such as chemotherapy or myelofibrosis.
Simple experiment design for impulsive force measure at hammer and nail collisions
Authors: Untoro Nur , Ramdhan Muhammad
Published: September 2024

For approximately 2400 years BC, carpenters have been using hammers to nail wood. The reason for this method is unclear and evaluations of its effectiveness should not be made without proper research. Therefore, this study aims to develop a force-measuring instrument to analyze the impulsive forces produced during hammer strokes on nails. The measurement process is based on the laws of conservation of momentum and mechanical energy and the work-energy principle. The apparatus was constructed using a PVC pipe fitted with a rope pulley and load. The measurements were taken by dropping the mass onto nails embedded in the wooden specimens of keruing, teak, mahogany, and pine. The findings demonstrate that the impulsive force involved in driving nails into wood remains constant. This force is not influenced by the speed of the hammer swing, but rather by the wood’s level of hardness and penetration depth. Using harder wood results in a greater impulsive force, therefore, driving nails becomes more efficient in securing them into the wood.
Neural networks assisted Metropolis-Hastings for Bayesian estimation of critical exponent on elliptic black hole solution in 4D using quantum perturbation theory
Authors: Hatefi Armin , Hatefi Ehsan , Lopez-Sastre Roberto J.
Published: September 2024

It is well-known that the critical gravitational collapse produces continuous self-similar solutions characterized by the Choptuik critical exponent, γ. We examine the solutions in the domains of the linear perturbation equations, considering the numerical measurement errors. Specifically, we study quantum perturbation theory for the four-dimensional Einstein-axion-dilaton system of the elliptic class of SL(2,ℝ) transformations. We develop a novel artificial neural network-assisted Metropolis-Hastings algorithm based on quantum perturbation theory to find the distribution of the critical exponent in a Bayesian framework.
Unlike existing methods, this new probabilistic approach identifies the available deterministic solution and explores the range of physically distinguishable critical exponents that may arise due to numerical measurement errors.
The root cause of disruptive NTMs and paths to stable operation in DIII-D ITER baseline scenario plasmas
Authors: Bardoczi L. , Richner N.J. , Logan N.C. , Strait E.J. , Holcomb C.T. , Zhu J. , Rea C.
Published: September 2024

Analyses of the DIII-D ITER Baseline Scenario database support that the disruptive m,n=2,1 magnetic islands are pressure gradient driven, non-linear instabilities seeded in a sequence of stochastic transient magnetic perturbations, and that the current profile relaxation does not affect the m,n=2,1 island onset rate. At low torque, these Neoclassical Tearing Modes are most commonly seeded by non-linear 3-wave coupling when the differential rotation between the q=1 & q=2 rational surfaces approaches zero. Lack of statistically significant difference between the current profiles of stable and unstable states, as well as lack of correlation between the tearing mode onset rate and the current profile relaxation both reject causality between the current profile evolution and the 2,1 magnetic island onsets in these plasmas. These support that preserving the differential rotation between the q=1 and q=2 rational surfaces is key to long pulse stable operation in the plasma scenario planned for ITER, while optimization of the current profile within the explored parameter space may lead to much weaker improvements than sustaining the differential rotation.
A theoretical strain transfer model analysis of the substrate-bonded FBG sensor considering the influence of groove
Authors: Zhao Yingjiang , Li Mengzhen
Published: September 2024

This study introduces a novel theoretical model for
substrate-bonded FBG sensors aimed at eliminating strain transfer
error by considering the influence of the groove. The model
comprises two main components: the encapsulated FBG and the
substrate, with an assumptive plane acting as the connecting
link. The strain transfer relationship between the substrate-bonded
FBG sensor and the host material is deduced. Validation of the
theoretical predictions is achieved through finite element numerical
analysis and experimental validation, demonstrating good agreement
between the calculated values and both numerical simulation values
and experimental observations. Additionally, parametric analysis is
conducted to explore the impact of material and geometric features
on the strain transfer coefficient and the average strain transfer
coefficient.
A method of increasing the interquadrant resistance of four-quadrant p-i-n photodiodes
Authors: Kukurudziak M.S.
Published: September 2024

The paper investigates the influence of the insulation
resistance of the responsive elements and the guard ring of a
silicon 4-quadrant photodiode on its dark currents. It was found
that a decrease in the insulation resistance leads to an increase in
the dark current of the guard ring and responsive elements. It was
found that the insulation resistance deteriorates due to the
formation of surface inversion layers at the interface
Si-SiO2. A method of increasing the insulation resistance of
the active elements of the photodiode by etching oxide in the gaps
between the responsive elements is proposed, thereby removing the
conductive inversion channels. In the absence of an increase in the
insulation resistance after these modifications, it is proposed to
etch the surface layer of silicon in the gaps between the responsive
elements by chemical-dynamic polishing with a gold masking
layer. The proposed methods make it possible to significantly reduce
the dark currents of the photodiodes, increase the insulation
resistance between the responsive elements, and increase the
percentage of yield of suitable products.
Coherent X-ray emission from relativistic electrons in a three-layer target
Authors: Noskov A.V. , Blazhevich S.V.
Published: September 2024

In this paper, a coherent X-ray radiation of relativistic
electrons in a composite target is developed. The composite target
consists of two amorphous layers and one layer having a structure of
a periodic layered medium with three different layers per period,
located at a given angle relative to the target surface. The paper
considers coherent X-ray radiation behind the rear surface of a
target, i.e. radiation in a periodic layered medium, in the Laue
scattering geometry. Within the framework of the two-wave
approximation of the dynamic theory of X-ray diffraction in a
periodic layered medium, expressions are obtained that describe the
amplitudes of parametric X-ray radiation and diffracted transition
radiation. Then, the case when the second layer is a vacuum is
considered. Expressions are obtained that describe the
spectral-angular and angular densities of PXR, DTR and their
interference. The possibility of significantly increasing the
spectral-angular density of DTR due to the total contribution to it
of transition radiation waves from the amorphous layer, the front
boundary of the periodic layered structure and their constructive
interference is shown. The possibility of increasing the
spectral-angular and angular densities of DTR due to the choice of
the asymmetry of the reflection of the electron field and X-ray
radiation in the third layer is shown.
Average energy dissipation rates of explicit exponential Runge-Kutta methods for gradient flow problems
Authors: Liao Hong-lin , Wang Xuping
Published: September 2024

We propose a unified theoretical framework to examine the energy dissipation properties at all stages of explicit exponential Runge-Kutta (EERK) methods for gradient flow problems. The main part of the novel framework is to construct the differential form of EERK method by using the difference coefficients of method and the so-called discrete orthogonal convolution kernels. As the main result, we prove that an EERK method can preserve the original energy dissipation law unconditionally if the associated differentiation matrix is positive semi-definite. A simple indicator, namely average dissipation rate, is also introduced for these multi-stage methods to evaluate the overall energy dissipation rate of an EERK method such that one can choose proper parameters in some parameterized EERK methods or compare different kinds of EERK methods. Some existing EERK methods in the literature are evaluated from the perspective of preserving the original energy dissipation law and the energy dissipation rate. Some numerical examples are also included to support our theory.
A snapshot of the Minimal Model Program
Authors: Lehmann Brian
Published: September 2024

We briefly review the main goals of the minimal model program. We then discuss which results are known unconditionally, which are known conditionally, and which are still open.
Bringing Identity Back in the “Arab Uprisings”
Authors: Toska Silvana
Published: September 2024

This chapter examines the causal mechanism of the theory: how an identity neighborhood revolt influences the possibility of revolt elsewhere through the emotional diffusion and cognitive liberation to which it gives rise. It provides an overview of the diffusion of the Arab Uprisings preceded by a historical analysis of the nature of the shared identity between Arab countries. It uses evidence from interviews with revolutionaries to show whether the proposed mechanisms—emotional arousal and cognitive liberation—are activated during the spread of revolt. It shows that revolts in countries that do not share a close identity—such as the Iranian Green Revolution of 2009—barely resonated with activists in the rest of the Middle East. It also provides a bird’s eye view of the preexisting mobilizing structures in the Middle East and shows how revolt was more likely to spread to those countries that had them.
Syria and Saudi Arabia
Authors: Toska Silvana
Published: September 2024

This chapter examines a negative case, the nonspread of revolt to Saudi Arabia, as well as the violent revolt-turned-civil war in Syria. According to the theory put forth in this book, both countries should have experienced mobilizing emotions due to their shared identity with Tunisia and Egypt, but neither country should have erupted in revolt. Yet, Syria did. The first half of the chapter shows how even though revolt erupted in Syria, it did so in areas with preexisting opportunity structures. It then shows how the disjointed nature of the opposition made it easier for the military to stay loyal to the regime. The analysis of the Saudi Arabian case—the revolution that never happened—shows how emotional mobilization from neighboring events is insufficient for revolt and domestic opportunity structures are essential for mobilization.
A note on “Simple graphical rules to assess selection bias in general-population and selected-sample treatment effects” by M. B. Mathur and I. Shpitser
Authors: Stanghellini Elena , Doretti Marco , Tezuka Taiki
Published: September 2024

This short note is a commentary on a 2024 article by Mathur and Shpitser in the Journal, with the aim to enlarge the class of graphs for which the conditional average treatment effect is nonparametrically identified, by allowing the outcome to be on the pathway between the treatment and the selection indicator. A first straightforward generalization is possible when (1) the outcome $Y$ is binary, and (2) the population prevalence of $Y$ is known a priori or can be made the object of a sensitivity analysis. Furthermore, identification of the effect is possible also for $Y$ having any nature, provided that a selection bias breaking node $V$ exists and the population prevalence of $V$ is known.
Chronic binge alcohol mediated hepatic metabolic adaptations in SIV-infected female rhesus macaques
Authors: Gallegos Eden M , Simon Liz , Molina Patricia E
Published: September 2024

Aims

As the interactions of alcohol and HIV/SIV infection and their impact on liver metabolic homeostasis remain to be fully elucidated, this study aimed to determine alcohol-mediated hepatic adaptations of metabolic pathways in SIV/ART-treated female rhesus macaques fed a nutritionally balanced diet.

Methods

Macaques were administered chronic binge alcohol (CBA; 13–14 g ethanol/kg/week for 14.5 months; n = 7) or vehicle (VEH; n = 8) for 14.5 months. Livers were excised following an overnight fast. Gene and protein expression, enzymatic activity, and lipid content were determined using frozen tissue and histological staining was performed using paraffin-embedded tissue.

Results

CBA/SIV macaques showed increased hepatic protein expression of electron transport Complex III and increased gene expression of glycolytic (phosphofructokinase and aldolase) and gluconeogenic (pyruvate carboxylase) enzymes and of genes involved in lipid turnover homeostasis (perilipin 1, peroxisome proliferator-activated receptor gamma, carbohydrate responsive binding protein, and acetyl-CoA carboxylase B) as compared to that of livers from the VEH/SIV group. Plasma triglyceride concentration had a significant positive association with liver triglyceride content in the CBA/SIV group.

Conclusions

These results reflect CBA-associated alterations in expression of proteins and genes involved in glucose and lipid metabolism homeostasis without significant evidence of steatosis or dysglycemia. Whether these changes predispose to greater liver pathology upon consumption of a high fat/high sugar diet that is more aligned with dietary intake of PWH and/or exposure to additional environmental factors warrants further investigation.
Identification of sesquiterpene aldehydes as volatile antifungal compounds in Phaeolepiota aurea culture filtrate
Authors: Seki Kota , Tanaka Tomoya , Shimoda Emiko , Tanio Shinji , Yanagita Ryo C , Miyazaki Tsugumi , Tokumoto Kento , Tazawa Toshiaki , Osaki-Oka Kumiko , Ishihara Atsushi
Published: September 2024

The culture filtrate extract of golden bootleg (Phaeolepiota aurea) exhibited strong antifungal activity in a bioassay for volatile compounds. Purification of active compounds through silica gel column chromatography and high performance liquid chromatography isolated two compounds, 1 and 2, with molecular weights of 234 and 259, respectively, as confirmed by mass spectrometry. Nuclear magnetic resonance analysis identified these compounds as new sesquiterpenoids with the α-bourbonene skeleton. Both compounds had an aldehyde group, while 2 possessed a cyanohydrin group. These compounds were named phaeolep aldehydes A (1) and B (2). Phaeolep aldehyde A inhibited hyphae elongation of Penicillium citrinum, Aspergillus niger, Cladosporium sphaerospermum, and Alternaria brassicicola at 10 ppm, but did not exhibit any antibacterial activity. In contrast, phaeolep aldehyde B exhibited potent inhibitory effects on the spore germination of Pe. citrinum, achieving 58.2% inhibition at 0.25 ppm, outperforming phaeolep aldehyde A, which exhibited 25.7% inhibition at 10 ppm.
Small interfering RNA microneedle patches versus silicone sheets in reducing postoperative scars: a randomized single-blinded intraindividually controlled clinical trial
Authors: Lim Delwyn Zhi Jie , Chun Yong Yao , Tan Faith Nicole Shih Yun , Monteiro Amelia Yuting , Cheng Hui Mei , Lee Jia Yi , Tan Yingrou , Tan Timothy T Y , Tey Hong Liang
Published: September 2024

Background

A common complication of wounds is the excessive production of fibrotic scar tissue, which can lead to hypertrophic scars or keloids. Currently, no treatments with good evidence for preventing excessive scar tissue formation are available. We explored the use of microneedle patches containing small interfering RNA (siRNA) to inhibit SPARC mRNA in reducing the volume of postoperative scars.

Objectives

To compare differences in postoperative scar volume with the daily application of siRNA-embedded dissolving microneedle patches vs. silicone sheets.

Methods

This was an 8-week, single-blinded intraindividually controlled randomized trial at a tertiary dermatological centre. Patients with 2-week-old postoperative wounds were included. Each half of the scar was randomly assigned to the microneedle patch or silicone sheet. Three-dimensional (3D) volumes were obtained from the scars via a high-resolution scanner at days 0, 30 and 60. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000558729).

Results

At day 30, scars treated with microneedle patches had a lower geometric mean volume of 0.79 mm3 vs. scars treated with silicone sheets, with a difference in mean percentage volume reduction of 10.7%. At day 60, scars treated with microneedle patches had a statistically significant lower volume (8.88 mm3) compared with the side treated with silicone sheets (12.77 mm3; P = 0.005), with a difference in mean percentage reduction of 9.7%. Additionally, there was also a statistically significant difference between the percentage reduction in scar volume vs. baseline on the side treated with microneedle patches (mean 83.8%) compared with the side treated with silicone sheets (mean 74.1%).

Conclusions

There was a significantly greater reduction in the volume of postoperative scars on the side of the scar treated with microneedle patches compared with the side treated with silicone sheets. This demonstrates the use of transdermal gene-silencing technology in scar inhibition and that siRNA microneedle patches can be effective and safe in reducing scar tissue formation.
The single-phase computed tomographic angiography clot burden score is independently associated with digital subtraction angiography derived American Society of Interventional and Therapeutic Neuroradiology collateral score
Authors: Lakhani Dhairya A , Balar Aneri B , Koneru Manisha , Wen Sijin , Ozkara Burak Berksu , Wang Richard , Hoseinyazdi Meisam , Nabi Mehreen , Mazumdar Ishan , Cho Andrew , Chen Kevin , Sepehri Sadra , Xu Risheng , Urrutia Victor , Albers Greg W , Rai Ansaar T , Yedavalli Vivek S
Published: September 2024

Objectives

The variation in quality and quantity of collateral status (CS) is in part responsible for a wide variability in extent of neural damage following acute ischemic stroke from large vessel occlusion (AIS-LVO). Single-phase CTA based clot burden score (CBS) is a promising marker in estimating CS. The aim of this study is to assess the relationship of pretreatment CTA based CBS with the reference standard Digital subtraction angiography (DSA) based American Society of Interventional and Therapeutic Neuroradiology (ASITN) CS.

Methods

In this retrospective study, inclusion criteria were as follows: (1) Anterior circulation LVO confirmed on CTA from January 9, 2017 to January 10, 2023; (2) diagnostic CTA; and (3) underwent mechanical thrombectomy with documented DSA CS. Spearman’s rank correlation analysis, multivariate logistic regression and ROC analysis was performed to assess the correlation of CTA CBS with DSA CS. P ≤ .05 was considered significant.

Results

292 consecutive patients (median age = 68 years; 56.2% female) met our inclusion criteria. CTA CBS and DSA CS showed significant positive correlation (ρ = 0.51, P < .001). On multivariate logistic regression analysis CBS was found to be independently associated with DSA CS (adjusted OR = 1.83, P < .001, 95% CI: 1.54-2.19), after adjusting for age, sex, race, hyperlipidemia, hypertension, diabetes, prior stroke or transient ischemic attack, atrial fibrillation, premorbid mRS, admission NIH stroke scale, and ASPECTS. ROC analysis of CBS in predicting good DSA CS showed AUC of 0.76 (P < .001; 95% CI: 0.68-0.82). CBS threshold of > 6 has 84.6% sensitivity and 42.3% specificity in predicting good DSA CS.

Conclusion

CTA CBS is independently associated with DSA CS and serves as a valuable supplementary tool for CS estimation. Further research is necessary to enhance our understanding of the role of CTA CBS in clinical decision-making for patients with AIS-LVO.

Advances in knowledge

CBS by indirectly estimating CS has shown to predict outcomes in AIS-LVO patients. No studies report association of CBS with reference standard DSA. In this study we further establish CBS as an independent marker of CS.