bluuebunny/crossref_metadata_2025 huggingface dataset:
Mode transition mechanisms in semi-passive flapping-wing propulsion or energy extraction
Authors: Zhu Bing , Wang Feilin , Xu Wenjun , Xiao Qisheng
Published: December 2023

To facilitate the smooth transition of operational modes in self-sustaining micro-thrusters, this study focuses on a device employing semi-passive flapping wings. Transient numerical methods are used to analyze the variation of flap energy acquisition and propulsion characteristics with pitching frequency, and the relationship between the dominant vortex structure and the force characteristics is analyzed by using the integral momentum theorem and the dynamic mode decomposition (DMD) method. The results indicate that, under the investigated operational conditions, with an increase in the pitching frequency, distinct wake evolution characteristics were observed. In the energy harvesting operational regime, the wake patterns manifest as 2P + mS, 2S + mS, and mS types. During the transitional phase from energy harvesting to propulsion, the wake patterns shift from 2S + mS to 2S transitional types, eventually leading to the manifestation of a reverse Karman vortex street (2S RBVK). In the propulsion operational regime, the wake patterns consist of a reverse Karman vortex street and asymmetric reverse Karman vortex street phenomena. Simultaneously, it was observed that the transition of flapping-wing performance from energy harvesting to propulsion conditions delays behind the transformation of vortex street structures. This delay is attributed to the necessity for the flapping-wing device to overcome its own resistance before generating a net effective propulsive force. The contributions of unsteady wake to thrust primarily encompass vortex thrust, thrust due to localized fluid acceleration, induced momentum force, and induced pressure force. As the pitching frequency increases, the influence of wake vortices on propulsion also intensifies. The contribution of wake vortices to flapping-wing propulsion is determined by the spatial distribution of Lamb vectors and localized fluid accelerations. The conclusions drawn from the dynamic modal analysis and reconstructed flow field analysis of wake vortices align with the findings of the investigation of wake vortices based on the integral momentum theorem.
Tuning magnon spectra via interlayer coupling in pseudo-3D nanostructured artificial spin ice arrays
Authors: de Rojas Julius , Atkinson Del , Adeyeye Adekunle O.
Published: December 2023

We have investigated the static and dynamic behavior of “pseudo-3D” trilayer square artificial spin ice structures. The trilayer stack comprises of two ferromagnetic Ni81Fe19 (Permalloy, Py) layers with 30 and 70 nm thickness, separated by a nonmagnetic copper layer of varying thickness from 2 to 40 nm. We show that the copper thickness enables interlayer coupling between layers to be finely controlled, leading to bespoke magnetization states and resonance spectra tuning. Our results demonstrate a further route to control the interaction in artificial spin ices beyond planar structures, enabling tunable magnetization dynamics, a potentially programmable degree of freedom for magnonic and microwave devices.
Dynamics of large cavity induced by valve closure in an undulating pipeline
Authors: Wu Guohong , Zhu Jianghui , Han Huan , Liu Zongku , Li Xiaoqin , Tang Xuelin
Published: December 2023

The dynamics of large cavity and the accompanied water column separation and rejoining induced by fast closing of a butterfly valve in an undulating pipeline system are investigated in this study. The three-dimensional computational fluid dynamics numerical simulations are performed using a newly developed interfacial surface tension-based model (ISTM) that accounts for the surface tension effect on large cavities. The applicability of the ISTM model is validated with the experimental data, showing better accuracy in predicting pressure fluctuations and cavity evolutions than three typical cavitation models. Differences in cavitation characteristics are observed between upstream and downstream of the valve. Upstream the valve, cavitation primarily appears at the pipe top, with the vapor volume fraction varying sharply due to the rarefaction pressure waves (maximum value of 0.0073). Downstream the valve, the complete water-column separation occurs, and vapor volume fraction changes slowly correspond with the growth and collapse of the large cavity (maximum value of 0.647). The maximum length of the large cavity can reach about six times the pipe diameter, with a minimum water vapor interface angle of 16°. The cavitation evolution displays a transition from a clustered inception to a sheet-like growth and collapse pattern. These findings contribute to the design and operation guidance for complex hydraulic systems during transient processes.
Efficient Hartree–Fock exchange algorithm with Coulomb range separation and long-range density fitting
Authors: Sun Qiming
Published: December 2023

Separating the Coulomb potential into short-range and long-range components enables the use of different electron repulsion integral algorithms for each component. The short-range part can be efficiently computed using the analytical algorithm due to the locality in both the Gaussian-type orbital basis and the short-range Coulomb potentials. The integrals for the long-range Coulomb potential can be approximated with the density fitting method. A very small auxiliary basis is sufficient for the density fitting method to accurately approximate the long-range integrals. This feature significantly reduces the computational efforts associated with the N4 scaling in density fitting algorithms. For large molecules, the range separation and long-range density fitting method outperforms the conventional analytical integral evaluation scheme employed in Hartree–Fock calculations and provides more than twice the overall performance. In addition, this method offers a higher accuracy compared to conventional density fitting methods. The error in the Hartree–Fock energy can be easily reduced to 0.1 μEh per atom or smaller.
A multi-limiter method for simulating complex flows on large grids
Authors: Schoppe Justin , Cizmas Paul G. A.
Published: December 2023

This paper presents a novel method for aiding the convergence of complex flows simulations on large grids. In this work, large grids are considered those that are of the order of 100 × 106 cells or more. These large grids, which, for example, model the flow around a powered airplane, are typically difficult to generate and modify. If a high-fidelity solution is needed, as in the case of predicting sonic boom, the amount of numerical dissipation must be minimized. This reduced dissipation, however, may result in solution divergence, triggered by improperly resolved large gradients due to grid deficiency. Using a highly dissipative limiter for the entire grid could avoid solution divergence, but the resulting solution may be less accurate. To avoid the loss of solution accuracy due to too much numerical dissipation, we present an approach in which the flow solver uses two limiters: a low-dissipation limiter for the vast majority of the computational domain, and a high-dissipation limiter for the regions where the grid is not adequate for capturing the flow variation and would otherwise lead to the divergence of the solution. The paper demonstrates that (1) the overall solution is not modified by the local use of the high-dissipation limiter, and (2) for a case in which the use of low-dissipation limiter (Venkatakrishnan) resulted in solution divergence, a converged solution is obtained by using the low-dissipation limiter on the vast majority of the grid and a high-dissipation limiter (van Albada) on the region where the mesh was problematic. The effect of a local high-dissipation limiter on the overall solution is explored on a double-wedge canonical airfoil. The multi-limiter approach is then used to predict the near field pressure of the X-59 airplane.
Finite-amplitude instability of the convection in a porous vertical slab with horizontal heterogeneity in permeability
Authors: Xiao Yue , Li Qiao , Wang Shaowei , Zhao Moli
Published: December 2023

The finite-amplitude instability of the natural convection in a vertical porous slab filled with variable permeability porous medium is investigated analytically. The side walls of the slab are kept at different temperatures, and the permeability in the horizontal direction is assumed to be exponential heterogeneous models. Two-dimensional, finite-amplitude solutions for the thermal buoyant flow are obtained for Darcy–Rayleigh numbers close to the critical values by using the amplitude expansion method. The dependence of the fundamental mode, the distortion of the mean flow, and the second harmonic upon the variable permeability constant are discussed. By calculating the first Landau coefficient, the primary bifurcations in the vicinity of the neutral stability curves are identified. The results show that only supercritical bifurcations are found to occur, rather than subcritical instabilities. In terms of the well-known Landau equation, the threshold amplitude of the nonlinear equilibrium solution is analyzed as well.
Three common assumptions about inflammation, aging, and health that are probably wrong
Authors: McDade Thomas W.
Published: December 2023

Chronic inflammation contributes to the onset and progression of cardiovascular disease and other degenerative diseases of aging. But does it have to? This article considers the associations among inflammation, aging, and health through the lens of human population biology and suggests that chronic inflammation is not a normal nor inevitable component of aging. It is commonly assumed that conclusions drawn from research in affluent, industrialized countries can be applied globally; that aging processes leading to morbidity and mortality begin in middle age; and that inflammation is pathological. These foundational assumptions have shifted focus away from inflammation as a beneficial response to infection or injury and toward an understanding of inflammation as chronic, dysregulated, and dangerous. Findings from community-based studies around the world—many conducted in areas with relatively high burdens of infectious disease—challenge these assumptions by documenting substantial variation in levels of inflammation and patterns of association with disease. They also indicate that nutritional, microbial, and psychosocial environments in infancy and childhood play important roles in shaping inflammatory phenotypes and their contributions to diseases of aging. A comparative, developmental, and ecological approach has the potential to generate novel insights into the regulation of inflammation and how it relates to human health over the life course.
Gravity of gluonic fluctuations and the value of the cosmological constant
Authors: Mackewicz Kris , Hogan Craig
Published: December 2023

We analyze the classical linear gravitational effect of idealized pion-like dynamical systems, consisting of light quarks connected by attractive gluonic material with a stress–energy

p
=
−
ρ

c
2

in one or more dimensions. In one orbit of a system of total mass M, quarks of mass

m
<<
M

expand apart initially with

v

/

c
∼
1

, slow due to the gluonic attraction, reach a maximum size

R
0

∼
ℏ

/

M
c

, then recollapse. We solve the linearized Einstein equations and derive the effect on freely falling bodies for two systems: a gluonic bubble model where uniform gluonic stress–energy fills a spherical volume bounded by a 2D surface comprising the quarks’ rest mass, and a gluonic string model where a thin string connects two pointlike quarks. The bubble model is shown to produce a secular mean outward residual velocity of test particles that lie within its orbit. It is shown that the mean gravitational repulsion of bubble-like virtual-pion vacuum fluctuations agrees with the measured value of the cosmological constant, for a bubble with a radius equal to about twice the pion de Broglie length. These results support the view that the gravity of standard QCD vacuum fluctuations is the main source of cosmic acceleration.
Berry phase of spin-one system in a rotating electric field
Authors: Alizzi Abdaljalel , Silagadze Zurab K , Uskov Artem
Published: December 2023

We consider in detail how the Berry phase arises in a rotating electric field in a model system with spin one. The goal is to help the student who first encountered this interesting problem, which is fraught with some subtleties that require attention in order not to go astray.
An educational model of the Deutsch algorithm for secondary school
Authors: Sutrini Claudio , Zuccarini Giacomo , Malgieri Massimiliano , Bondani Maria , Macchiavello Chiara
Published: December 2023

In this paper, we present the outline of an educational path to introduce a crucial historical turnpoint of quantum information research—namely the Deutsch algorithm—to secondary school students. We discuss a basic elementarization strategy allowing students to single out and focus on the individual features of quantum mechanics involved in the different steps of the algorithm information processing phase, which can potentially be useful for the educational reconstruction of other algorithms and protocols. The sequence includes the experimental realization on the optical bench of an analogue of the Deutsch algorithm, working with classical coherent light. The educational path was tested both in curricular and out-of-school settings, and preliminary results will be discussed.
Topological phases of monolayer and bilayer depleted Lieb lattices
Authors: Sil Arghya , Ghosh Asim Kumar
Published: December 2023

Existence of nontrivial topological phases in a tight binding Haldane-like model on the depleted Lieb lattice is reported. This two-band model is formulated by considering the nearest-neighbor (NN), next-NN (NNN) and next-NNN hopping terms along with complex phase which breaks the time reversal symmetry of this semi-metallic system. Topological feature of this model is studied along with the presence of sublattice symmetry breaking staggered onsite energy. Combined effect of these two broken symmetries is found crucial for an additional transition between nontrivial and trivial phases. System exhibits two types of phase transitions, say, between two nontrivial phases and nontrivial to trivial phases. Nonzero Chern numbers, existence of Hall plateau and symmetry protected edge states confirm the presence of the nontrivial phases. This two-band system hosts four different types of phases where two are topological. Additionally topological properties of stacked bilayer of the depleted Lieb lattices is also studied with similar Haldane-like Hamiltonian. This four-band system is found to host Chern insulating phases, with higher values of Chern numbers supported by in-gap edge states.
Circular dichroism in two-dimensional BC6N and B3C2N3 in absence of intervalley excitonic coupling
Authors: Adhikary Souren , Dutta Sudipta
Published: December 2023

Two-dimensional (2D) noncentrosymmetric systems offer potential opportunities for exploiting the valley degrees of freedom for advanced information processing, owing to non-zero Berry curvature. However, such valley polarization in 2D materials is crucially governed by the intervalley excitonic scattering in momentum space due to reduced electronic degrees of freedom and consequent enhanced electronic correlation. Here, we study the valley excitonic properties of two 2D noncentrosymmetric complementary structures, namely, BC6N and B3C2N3 using first principles-based GW calculations combined with the Bethe–Salpeter equation, that brings the many-body interactions among the quasiparticles. The k-resolved oscillator strength of their first bright exciton indicates their ability to exhibit valley polarization under the irradiation of circularly polarized light of different chiralities. Both the systems show significant singlet excitonic binding energies of 0.74 eV and 1.31 eV, respectively. Higher stability of dark triplet excitons as compared to the singlet one can lead to higher quantum efficiency in both the systems. The combination of large excitonic binding energies and the valley polarization ability with minimal intervalley scattering make them promising candidates for applications in advanced optical devices and information storage technologies.
Applications of electronic nose technology in the tobacco industry: a comprehensive review
Authors: Du Shantao , Xi Gaolei , Chen Xia , Wang Xingguo , Ai Bin , Wu Shufang , Li Shaohua , Zhao Weimin
Published: December 2023

Electronic nose (E-nose) technology has emerged as a promising tool for rapid and objective analysis of complex odor profiles in various industries, including the tobacco sector. This review paper provides a comprehensive overview of the applications of E-noses in the tobacco industry, focusing on their potential for enhancing quality control, optimizing blend formulations, monitoring processing conditions, and assuring the quality of finished products. We discuss the basic principles, working mechanisms, sensor types, and data processing techniques employed in E-noses, as well as the challenges and limitations associated with their adoption in the tobacco industry. These challenges include sensor drift, calibration, interference from environmental factors, the complexity of tobacco aroma and flavor profiles, and regulatory and ethical considerations. The paper concludes by highlighting the need for further research and development in E-nose technology, with an emphasis on addressing technical challenges, refining sensor systems, and fostering collaboration among researchers, industry stakeholders, and regulatory agencies. By overcoming these hurdles, E-nose technology has the potential to revolutionize the tobacco industry, ensuring consistent product quality, and meeting the changing demands of consumers while addressing public health concerns and regulatory requirements.
Preliminary study of low-pressure ionization chamber for online dose monitoring in FLASH carbon ion radiotherapy
Authors: Lang Xinle , Hu Zhengguo , Zhao Zulong , Zhou Kai , Xu Zhiguo , Li Min , Mao Ruishi , Luo Faming , Huang Chuan , Kang Xincai , Li Juan , Liu Xiaotao , Zhou Libin , Xiao Guoqing
Published: December 2023

The FLASH effect of carbon ion therapy has recently attracted significant attention from the scientific community. However, the radiobiological mechanism of the effect and the exact therapeutic conditions are still under investigation. Therefore, the dosimetry accuracy is critical for testing hypotheses about the effect and quantifying FLASH Radiotherapy. In this paper, the FLASH ionization chamber at low-pressure was designed, and its dose rate dependence was verified with the Faraday cup. In addition, the dose response was tested under the air pressure of the ionization chamber of 10 mbar, 80 mbar and 845 mbar, respectively. The results showed that when the pressure was 10 mbar, the dose linearity was verified and calibrated at the dose rate of ∼50 Gy s−1, and the residuals were less than 2%. In conclusion, the FLASH ionization chamber is a promising instrument for online dose monitoring.
The possible effect of surface barriers on the magnetic levitation of cylindrical superconductors
Authors: Bernstein Pierre , Xing Yiteng , Noudem Jacques , Morandi Antonio , Ribani Pier Luigi , Russo Giacomo
Published: December 2023

Superconducting magnetic levitation force measurements on large field cooled cylindrical MgB2 bulks with different diameters and thicknesses are reported. For these experiments, a special set-up permitting one to measure forces up to 500 N was used. In contradiction to previous measurements, the obtained force hysteresis cycles could not be reproduced with the analytical mean field model proposed by Bernstein et al (2017 Supercond. Sci. Technol.
30 065007). The failure of the model has been attributed to surface barriers effects which were not taken into account in the model. This last one was accordingly modified in order that the measured force cycles could be reproduced. Contrary to most other models describing surface barriers effects, the modified model suggests that above a threshold field anti-vortices and not vortices enter the superconductor. This behaviour is related to the storage by the superconductor of the mechanical work done by the operator. In addition, it has turned out that the threshold field is a decreasing function of the critical surface current density of the samples. As a consequence, the surface barriers effects occur only if this quantity and the critical current density are large enough. Otherwise, the internal magnetic field of the superconductor could be computed and was seen to be a decreasing function of the thickness of the superconductors.
Scroll-growing/controlling chaotic attractors in cyclic Hopfield neural networks via memristive bridging
Authors: Chen Jian , Chen Zhuguan , Xu Quan , Bao Han
Published: December 2023

In this paper, a memristor-based neural network is proposed, which is implemented by two tri-neuron resistive-cyclic Hopfield neural networks (RC-HNNs) via memristive bridging. The memristor-bridged network has a line equilibrium set composed of infinitely many index-2 saddle-foci, but it can produce multi-scroll chaotic attractors contrary to Shil’nikov’s criterion. Complex bifurcation behaviors, scroll-growing chaotic attractors over time, and homogeneous coexisting attractors are revealed by numerical methods. Further, a scroll-control scheme is designed and scroll-controlling chaotic attractors are demonstrated numerically. The results show that the memristor-bridged network can not only generate scroll-growing chaotic attractors over time, but also produce scroll-controlling chaotic attractors by limiting the dynamic range of the internal state of the bridging memristor. Finally, an analog electronic circuit is designed for the memristor-bridged network, and PSIM circuit simulations are used to verify the numerical simulations.
Cooperative roles of mechanical behavior and chemical reactions in mechanical chemical nano cutting of graphene assisted by ·OH radicals: quantum mechanics and reaction molecular dynamics simulations
Authors: Tang Meiling , Yuan Zewei , He Yan , Sun Jingting , Wang Ying , Zhou Xinbo
Published: December 2023

In order to achieve precise and controllable cutting of graphene and to meet the high quality of cutting edges required in electronics. In this study, the tangential force, radial distribution function, dangling bonds, oxidation bonds, and density functional theory were used to investigate the mechanical behaviour, cutting damage, microscopic mechanism of chemical reactions, and feasibility of elementary reactions in mechanical chemical nano cutting graphene with different solution environments. The results show that the difference in the number of broken and interfacial bonds, dominated by the variability of chemical interactions, leads to a difference in cutting forces, and that there is a negative correlation between the number of C–C bonds and the number of C–O bonds. In the pure H2O solution environment, the unsaturated C atoms in the carbon chain undergo adsorption reactions with the solution atoms, which shows the carbon chain structures such as –C#–H2O, –C#–H, –C#–O and –C#–O. In the ·OH solution environment, the edge structure atoms obtained by mechanical chemical nano cutting of graphene are more structured, more C–O interfacial bonds are formed, and the C atoms are able to detach from the graphene in the form of C*O2. The energy barriers in the elementary reactions need to be overcome by the mechanical action of the probe, and the cooperative roles of mechanical behaviour and chemical reaction enables oxidation and smooth cutting of atoms at the slit edges of graphene.
Spin direction dependent quantum anomalous Hall effect in two-dimensional ferromagnetic materials
Authors: Yang 杨 Yu-Xian 宇贤 , Zhang 张 Chang-Wen 昌文
Published: December 2023

We propose a scheme for realizing the spin direction-dependent quantum anomalous Hall effect (QAHE) driven by spin–orbit couplings (SOC) in two-dimensional (2D) materials. Based on the sp3 tight-binding (TB) model, we find that these systems can exhibit a QAHE with out-of-plane and in-plane magnetization for the weak and strong SOC, respectively, in which the mechanism of quantum transition is mainly driven by the band inversion of p
x,y
/p
z
orbitals. As a concrete example, based on first-principles calculations, we realize a real material of monolayer 1T-SnN2/PbN2 exhibiting the QAHE with in-plane/out-of-plane magnetization characterized by the nonzero Chern number C and topological edge states. These findings provide useful guidance for the pursuit of a spin direction-dependent QAHE and hence stimulate immediate experimental interest.
Performance of Single Cell and Double Stacked Thermoelectric Generator Modules for Low Temperature Waste Heat Recovery
Authors: Mohamed W A N W , Zamri N F , Hamdan M H , Shah H J M F , Hanim N H M
Published: December 2023

Thermoelectric generator (TEG) is an energy conversion technology that is capable of converting temperature difference into electrical output. This manuscript focused on different design setups of TEG module in recovering waste heat captured from hydrogen fuel cell vehicle (FCV) into useful electrical energy. Effects of single cell (SC) and double stacked (DS) TEG configurations were analysed before an additional heat sink (HS) was installed in the heating section for heat transfer enhancement. The performance of all design setups was tested under waste heat temperature (Twh) of 53°C and 58°C. Under Twh of 58°C, the maximum power point (MPP) was enhanced from 0.23mW/cm2 (SC TEG design setup) to 2.8mW/cm2 (DS TEG configuration with HS addition design setup), by approximately 92%. Rapid increase in MPP was obtained as HS was applied in the TEG module due to higher rate of waste heat capturing. The installation of HS is proved to be a successful add-on to the TEG module for WHR from low temperature waste heat.
Biogas Production from Palm Oil Mill Effluent at Low pH
Authors: Zainal Bidattul Syirat , Farred Wan Adam Fitri Wan Mohd , Mohamed Hassan , Aziz Nur Atiqah Mohamad , Junoh Hazlina , Shamsuddin Abd Halim
Published: December 2023

The palm oil industry in Malaysia has aided our economy, but with any thriving industry comes the baggage of industrial waste. This paper focuses on palm oil mill effluent (POME), a waste product formed by palm oil milling operations. The objective of this paper is to evaluate the ability of POME to generate biogas through acid and heat pre-treatment methods. The feasibility of producing biogas at pH levels lower than 5 was investigated. The inoculum is effective microbe 1 (EM1), and the substrate is a liquid POME. Hydrochloric and phosphoric acid were used in this study, and the effect of low initial pH on biogas generation was investigated. The results show that POME alone produced the highest biogas volume (20.1 Nml). However, POME incubated with activated EM1 inoculant at low pH (3.74) generated consistent biogas during 57.75 hours of digestion. In conclusion, the EM1 is a good source of inoculum for POME treatment at low pH, with no pre-treatment required. The pre-treatment methods proposed in this study could have opened new doors for bio-renewable energy research, particularly in agricultural biomass, since substrate pre-treatment can enhance biogas production.
Energy Performance Review of Battery-Powered Drones for Search and Rescue (SAR) Operations
Authors: Ali Muhammad Firdaus Mohd , Jamaludin Jafferi , Ahmedy Ismail , Awalin Lilik Jamilatul
Published: December 2023

Drones and other aerial vehicles are commonly used in Search and Rescue (SAR) Operations to locate, stabilise, and extract distressed individuals. A drone is essentially a flying robot that can be remotely controlled or fly autonomously via software-controlled flight plans in their embedded systems, in conjunction with onboard sensors and a global positioning system (GPS). There are a variety of applications for drones today, and their use is expanding globally. It is a safe bet that the use of drones will continue to increase as technology continues to develop. Constantly raised by drone players is the issue of limited flight time due to poor battery life. Consequently, the purpose of this paper is to investigate the most recent research on the energy performance evaluation of battery-powered drones for search and rescue (SAR) operations.
Performance analysis of power electronics learning equipment
Authors: Ghafar Ridhwan , Yusof Yushaizad
Published: December 2023

This paper proposes an initiative of Power Electronics Learning Equipment (PELE), a power electronics learning tool that functions as an isolated gate signal generator to enable the operations of controlled power switches and semi-controlled power switches in AC-DC, AC-AC, DC-DC and DC-AC power converters circuits to provide a significant contribution towards students learning pedagogy. Before the introduction of PELE, a performance analysis of PELE is implemented and discussed with the objective to improve the equipment in 2 criteria which are its accuracy and precisions. Therefore, the performance of PELE is validated by measuring and comparing its input and output signals while varying the circuit parameters via laboratory experiment. Based on the power converter circuits experiments results, PELE has successfully and safely adjusted and regulated the operation of power converter circuits according to the stipulated targets.
Deep learning approaches to recover the plasma current density profile from the safety factor based on Grad–Shafranov solutions across multiple tokamaks
Authors: ZHANG 张 Hanyu 瀚予 , ZHOU 周 Lina 利娜 , LIU 刘 Yueqiang 钺强 , HAO 郝 Guangzhou 广周 , WANG 王 Shuo 硕 , YANG 杨 Xu 旭 , MIAO 苗 Yutian 雨田 , DUAN 段 Ping 萍 , CHEN 陈 Long 龙
Published: December 2023

Many magnetohydrodynamic stability analyses require generation of a set of equilibria with a fixed safety factor q-profile while varying other plasma parameters. A neural network (NN)-based approach is investigated that facilitates such a process. Both multilayer perceptron (MLP)-based NN and convolutional neural network (CNN) models are trained to map the q-profile to the plasma current density J-profile, and vice versa, while satisfying the Grad–Shafranov radial force balance constraint. When the initial target models are trained, using a database of semi-analytically constructed numerical equilibria, an initial CNN with one convolutional layer is found to perform better than an initial MLP model. In particular, a trained initial CNN model can also predict the q- or J-profile for experimental tokamak equilibria. The performance of both initial target models is further improved by fine-tuning the training database, i.e. by adding realistic experimental equilibria with Gaussian noise. The fine-tuned target models, referred to as fine-tuned MLP and fine-tuned CNN, well reproduce the target q- or J-profile across multiple tokamak devices. As an important application, these NN-based equilibrium profile convertors can be utilized to provide a good initial guess for iterative equilibrium solvers, where the desired input quantity is the safety factor instead of the plasma current density.
Telemedicine-based medical care compared to in-person medical care for warfarin follow-up: A retrospective propensity score matching cohort study
Authors: Alkhuzaee Fahad , Alsharif Sahar , Shukry Murooj
Published: December 2023

Purpose

Telemedicine is underutilized in Saudi Arabia, which is a matter of concern, especially since previous literature has showed its equivalence with office visits in providing access to care and convenience for patients while reducing anticoagulation-related bleeding events when appropriate measures are followed. The purpose of this study is to analyze the efficacy of telehealth-based care compared to in-person visit care for warfarin follow-up.

Methods

The authors conducted a retrospective chart review comparing the mean percentage of time in the therapeutic range (TTR) of international normalized ratio (INR) values among patients prescribed warfarin from July 2019 to November 2020 at King Faisal Specialist Hospital & Research Center – Jeddah Branch whose anticoagulant therapy was managed via telemedicine or through in-person clinic visits. A subcohort analysis of outcomes in the telemedicine and in-person groups was performed using propensity score matching, and descriptive analysis was done for the entire cohort.

Results

A total of 350 patient records were included in this retrospective study. Matched analysis for 148 patients using propensity score matching showed that the mean (SD) percentages of TTR were 62.82% (19.46%) and 70.61% (19.83%) in the telemedicine and in-person groups, respectively (P = 0.017). There was no statistical difference in the incidence of major or minor bleeding events, thromboembolic events, and hospital readmission between the two groups.

Conclusion

The study results showed that patients on oral anticoagulation therapy managed through a telemedicine method had a lower overall TTR percentage than a matched group of patients managed through in-person anticoagulant clinic visits, thus demonstrating that using a telemedicine approach alone for warfarin follow-up may not help patients to maintain their INR target level.
Botulinum Toxin Treatment for Calf Contouring Based on the Study of Combined Injection of Gastrocnemius and Soleus
Authors: Li Zhijin , Chong Yuming , Jin Lin , Zeng Ang , Huang Jiuzuo , Long Xiao , Yu Nanze , Wang Xiaojun
Published: December 2023

Background

Botulinum toxin is administered to paralyze the gastrocnemius muscle and reduce its size, thereby improving the calf contour and reducing the leg circumference of the calf.

Objectives

In pursuit of better efficacy, we designed a new injection protocol that targeted both the gastrocnemius and soleus. An algorithm of botulinum toxin injection for calf contouring was proposed based on the results of the study and ultrasonographic data.

Methods

A prospective, self-controlled, double-blind study was conducted. The gastronemius muscle (GM) group (n = 17) included the patients whose gastrocnemius muscles were treated, and the GM + soleus muscle (SM) group (n = 17) included the patients who had both the gastrocnemius and soleus treated. Parameters including the maximum leg circumference and the subcutaneous fat, gastrocnemius muscle, and soleus muscle thicknesses were collected before and after injection.

Results

Both GM and GM + SM injection helped improve calf contour. Although the thickness of the gastrocnemius muscle was reduced, reducing the leg circumference, the subcutaneous fat and soleus muscle had compensatory thickening after injection, especially over the long term, which may affect the efficacy. Compared with the GM group, the GM + SM group effectively reduced the tendency of the soleus muscle to thicken. Calf muscle thickness could be roughly estimated by constructing a fitting equation and measuring height, weight, and leg circumference.

Conclusions

Two injection methods achieved the effect of improving calf contour and reducing the leg circumference with equivalent patient satisfaction. The GM + SM injection group did not show any obvious extra clinical benefit when compared with the GM injection group.

Level of Evidence: 2
Plant polysaccharide degradation-related enzymes in Aspergillus oryzae
Authors: Matsuzawa Tomohiko
Published: December 2023

Plants synthesize large amounts of stored and structural polysaccharides. Aspergillus oryzae is used in traditional Japanese fermentation and produces many types of plant polysaccharide degradation-related enzymes. The carbohydrate-active enzymes of A. oryzae are important in the fermentation process and biotechnological applications. Because plant polysaccharides have a complex structure, cooperative and synergistic actions of enzymes are crucial for the degradation of plant polysaccharides. For example, the cooperative action of isoprimeverose-producing oligoxyloglucan hydrolase, β-galactosidase, and α-xylosidase is important for the degradation of xyloglucan, and A. oryzae coordinates these enzymes at the expression level. In this review, I focus on the plant polysaccharide degradation-related enzymes identified in A. oryzae.
Wharton’s jelly and osteoarthritis of the knee
Authors: Aratikatla Adarsh , Maffulli Nicola , Gupta Manu , Potti Ishana A , Potty Anish G , Gupta Ashim
Published: December 2023

Introduction

The existing treatment modalities for knee osteoarthritis (OA) do not actually address the pathology. Biological therapies, including those using material derived from perinatal tissues, represent a ground-breaking approach to alleviating the symptoms of OA of the knee.

Source of data

Current scientific literature published in PubMed (MEDLINE), Embase and Scopus databases. Trials registered in various clinical trial databases.

Areas of agreement

Perinatal tissues including Wharton’s jelly (WJ) and associated mesenchymal stem cells (MSCs) can be used for the management of knee OA.

Areas of controversy

The efficacy of WJ and associated MSCs in the management of knee OA is still controversial.

Growing points

The use of WJ and associated MSCs in the management of knee OA is safe and appears to be effective.

Areas timely for developing research

The present published evidence suggests that WJ tissue and associated MSCs offer an encouraging alternative for the management of knee OA. The published in vitro, preclinical and clinical investigations demonstrate the therapeutic potential of WJ and promote further research in this field to provide symptomatic relief to patients suffering from OA, aiming also to regenerate the osteoarthritic hyaline cartilage, with disease-modifying effects. Future adequately powered randomized controlled trials should be undertaken to establish whether WJ is helpful in the management of OA of the knee.
Neural correlates of prediction error in patients with schizophrenia: evidence from an fMRI meta-analysis
Authors: Yang Xun , Song Yuan , Zou Yuhan , Li Yilin , Zeng Jianguang
Published: December 2023

Abnormal processes of learning from prediction errors, i.e. the discrepancies between expectations and outcomes, are thought to underlie motivational impairments in schizophrenia. Although dopaminergic abnormalities in the mesocorticolimbic reward circuit have been found in patients with schizophrenia, the pathway through which prediction error signals are processed in schizophrenia has yet to be elucidated. To determine the neural correlates of prediction error processing in schizophrenia, we conducted a meta-analysis of whole-brain neuroimaging studies that investigated prediction error signal processing in schizophrenia patients and healthy controls. A total of 14 studies (324 schizophrenia patients and 348 healthy controls) using the reinforcement learning paradigm were included. Our meta-analysis showed that, relative to healthy controls, schizophrenia patients showed increased activity in the precentral gyrus and middle frontal gyrus and reduced activity in the mesolimbic circuit, including the striatum, thalamus, amygdala, hippocampus, anterior cingulate cortex, insula, superior temporal gyrus, and cerebellum, when processing prediction errors. We also found hyperactivity in frontal areas and hypoactivity in mesolimbic areas when encoding prediction error signals in schizophrenia patients, potentially indicating abnormal dopamine signaling of reward prediction error and suggesting failure to represent the value of alternative responses during prediction error learning and decision making.
Electrical stimulation induced self-related auditory hallucinations correlate with oscillatory power change in the default mode network
Authors: Yang Jing , Shen Lu , Long Qiting , Li Wenjie , Zhang Wei , Chen Qi , Han Biao
Published: December 2023

Self-related information is crucial in our daily lives, which has led to the proposal that there is a specific brain mechanism for processing it. Neuroimaging studies have consistently demonstrated that the default mode network (DMN) is strongly associated with the representation and processing of self-related information. However, the precise relationship between DMN activity and self-related information, particularly in terms of neural oscillations, remains largely unknown. We electrically stimulated the superior temporal and fusiform areas, using stereo-electroencephalography to investigate neural oscillations associated with elicited self-related auditory hallucinations. Twenty-two instances of auditory hallucinations were recorded and categorized into self-related and other-related conditions. Comparing oscillatory power changes within the DMN between self-related and other-related auditory hallucinations, we discovered that self-related hallucinations are associated with significantly stronger positive power changes in both alpha and gamma bands compared to other-related hallucinations. To ensure the validity of our findings, we conducted controlled analyses for factors of familiarity and clarity, which revealed that the observed effects within the DMN remain independent of these factors. These results underscore the significance of the functional role of the DMN during the processing of self-related auditory hallucinations and shed light on the relationship between self-related perception and neural oscillatory activity.
Intermittent migration can induce pulses of speciation in a two-island system
Authors: Princepe Débora , Czarnobai Simone , Caetano Rodrigo A , Marquitti Flavia M D , de Aguiar Marcus A M , Araujo Sabrina B L
Published: December 2023

Geographic barriers can come and go depending on natural conditions. These fluctuations cause population cycles of expansion and contraction, introducing intermittent migrations that may not hinder speciation but rather promote diversification. Here, we study a neutral 2-island speciation model with intermittent migration driven by sea-level fluctuations. Seabed depth modulates isolation and connection periods between the islands, with migration occurring during connection periods with a certain probability. Mating is restricted to genetically compatible individuals on the same island and offspring inherit genomes from both parents through recombination. We observe speciation pulses that would not occur under strict isolation or continuous migration, with infrequent, temporary increases in species richness happening at different times depending on the combination of geographic settings and migration probability. The resulting dynamic patterns of richness exhibit contrasting behavior between connected and isolated scenarios, often including species that do not persist. Prolonged isolation can reduce richness to 1 species per island, resembling patterns commonly associated with archipelagos under sea-level fluctuations. Together with other studies, our results in out-of-equilibrium populations support the relevance of investigating the impact of variable migration on diversification, particularly in regions of high diversity.
Overlap between the Mid-Atlantic Bight Cold Pool and offshore wind lease areas
Authors: Horwitz Rebecca , Miles Travis N , Munroe Daphne , Kohut Josh
Published: December 2023

The Mid-Atlantic Cold Pool is a seasonal mass of cold bottom water that extends throughout the Mid-Atlantic Bight (MAB). Formed from rapid vernal surface warming, the Cold Pool dissipates in the fall due to mixing events such as storms. The Cold Pool supports a myriad of MAB coastal ecosystems and economically valuable commercial and recreational fisheries. Offshore wind energy has been rapidly developing within the MAB in recent years. Studies in Europe demonstrate that offshore wind farms can impact ocean mixing and hence seasonal stratification; there is, however, limited information on how MAB wind development will affect the Cold Pool. Seasonal overlap between the Cold Pool and pre-construction wind lease areas at varying distances from shore in the MAB was evaluated using output from a data-assimilative ocean model. Results highlight overlap periods as well as a thermal gradient that persists after bottom temperatures warm above the threshold typically used to identify the Cold Pool. These results also demonstrate cross-shelf variability in Cold Pool evolution. This work highlights the need for more focused ocean modeling studies and observations of wind farm effects on the MAB coastal environment.
Blueberry floral probiotics: nectar microbes inhibit the growth ofColletotrichumpathogens
Authors: Rering Caitlin C , Lanier Alexia M , Peres Natalia A
Published: December 2023

Aims

To identify whether microorganisms isolated from blueberry flowers can inhibit the growth of Colletotrichum, an opportunistic plant pathogen that infects flowers and threatens yields, and to assess the impacts of floral microbes and Colletotrichum pathogens on artificial nectar sugars and honey bee consumption.

Methods and results

The growth inhibition of Colletotrichum (Colletotrichum acutatum, Colletotrichum fioriniae, and Colletotrichum gloeosporioides) was screened using both artificial nectar co-culture and dual culture plate assays. All candidate nectar microbes were screened for antagonism against a single C. acutatum isolate. Then, the top four candidate nectar microbes showing the strongest inhibition of C. acutatum (Neokomagataea thailandica, Neokomagataea tanensis, Metschnikowia rancensis, and Symmetrospora symmetrica) were evaluated for antagonism against three additional C. acutatum isolates, and single isolates of both C. fioriniae and C. gloeosporioides. In artificial nectar assays, single and three-species cultures inhibited the growth of two of four C. acutatum isolates by ca. 60%, but growth of other Colletotrichum species was not affected. In dual culture plate assays, inhibition was observed for all Colletotrichum species for at least three of four selected microbial antagonists (13%‒53%). Neither honey bee consumption of nectar nor nectar sugar concentrations were affected by any microbe or pathogen tested.

Conclusions

Selected floral microbes inhibited growth of all Colletotrichum species in vitro, although the degree of inhibition was specific to the assay and pathogen examined. In all microbial treatments, nectar sugars were preserved, and honey bee preference was not affected.