bluuebunny/crossref_metadata_2025 huggingface dataset:
Antibacterial Efficacy of Hiora: An Ayurvedic Mouthwash in
Children
Authors: Saha Sonali , Kalita Kongkana , Dhinsa Kavita , Arora Deval Kumar , Godhi Brinda Suhas , Doddawad Vidya Gowdappa
Published: August 2024

Background Mouthwashes, as a form of antimicrobial delivery system,
rank among the safest and most effective vehicles, particularly in the case
of young children. This is attributed to their ability to distribute
therapeutic components across all accessible oral surfaces, including
interproximal areas.

Objective To evaluate the antibacterial efficacy of recently
introduced Ayurvedic (Hiora) and triclosan-based mouthwashes among
children.

Materials and Methods A total of 45 healthy children aged 10–15 years
were randomly assigned to three groups: Herbal mouthwash (Hiora),
triclosan-based mouthwash (Kidodent), and normal saline as the control
group. Saliva samples were collected pre-rinse, 2 minutes, 30 minutes, and
60 minutes post-rinsing with the study mouthwashes. These samples were then
inoculated onto Petri dishes containing blood agar culture media, followed
by incubation under both aerobic and anaerobic conditions at 37°C for
48 hours. The resulting bacterial colonies of Streptococcus spp. and
Lactobacillus spp. were counted (CFU/ml x 105). Statistical
analysis, including ANOVA, Newman Keul’s Post-hoc test, and a two-tailed ‘t’
test, was conducted to determine the significance of the results.

Results The Ayurvedic Hiora mouthwash demonstrated the most
substantial reduction in salivary bacterial colony counts of
Streptococcus spp. and Lactobacillus spp. with
statistically significant results (p<0.01).

Conclusion The Ayurvedic Hiora mouthwash exhibited the highest
antibacterial effectiveness, followed by the triclosan-based mouthwash in
decreasing order, with saline showing the least efficacy.
Are There Left–Right Differences in Ruptured Middle Cerebral Artery Bifurcation Aneurysms? A Single-Center Retrospective Study and Review of the Literature
Authors: Inamasu Joji , Saito Katsuya
Published: August 2024

Background The left (Lt) and right (Rt) middle cerebral artery bifurcation (MCAB) aneurysms have mostly been regarded as identical. Considering substantial Lt–Rt differences in hemispheric infarction, however, the presence of Lt–Rt differences may not be denied totally in patients with ruptured MCAB aneurysms. We herein investigated whether such Lt–Rt differences existed by a single-center retrospective study.

Materials and Methods Clinical data prospectively acquired between 2011 and 2021 on 99 patients with ruptured MCAB aneurysms were analyzed. They were dichotomized based on the laterality, and demographic and outcome parameters were compared. Additionally, a literature review was conducted to elucidate possible Lt–Rt differences in the frequency of ruptured MCAB aneurysms (Rt/Lt ratio).

Results Among the 99 patients, 42 had Lt and 57 had Rt ruptured MCAB aneurysms, with the Rt/Lt ratio of 1.36. Neither demographic, radiographic, nor outcome variables differed significantly between the two groups. A total of 19 studies providing information on the laterality of the ruptured MCAB were retrieved by literature search. A sum total for the Lt and Rt MCAB aneurysms was 671 and 940, making the Rt/Lt ratio of 1.40. After adding our data, a sum total for the Lt and Rt MCAB aneurysms was 713 and 997, making the Rt/Lt ratio of 1.40.

Conclusion The Rt ruptured MCAB aneurysms were 1.40 times more frequent than the Lt-sided counterpart. While there may be some Lt–Rt differences in the MCA anatomy, it remains to be seen whether such anatomical differences are truly responsible for the disproportionately higher frequency of Rt MCAB aneurysms.
The active magnetic compensation coil
Authors: Xu Xueping , Liu Yi
Published: August 2024

The active magnetic compensation coil is of great significance for extensive applications, such as fundamental physics, aerospace engineering, national defense industry, and biological science. The magnetic shielding demand is increasing over past few decades, and better performances of the coil are required. To maintain normal operating conditions for some sensors, active magnetic compensation coils are often used to implement near-zero field environments. Many coil design methods have been developed to design the active compensation coil for different fields. It is opportune to review the development and challenges associated with active magnetic compensation coils. Active magnetic compensation coils are reviewed in this paper in terms of design methods, technology, and applications. Furthermore, the operational principle and typical structures of the coil are elucidated. The developments of the forward design method, inverse design method, and optimization algorithm are presented. Principles of various design methods and their respective advantages and disadvantages are described in detail. Finally, critical challenges in the active magnetic compensation coil techniques and potential research directions have been highlighted.
A practical guide for separator selection, characterization, and electrochemical evaluation for supercapacitor application
Authors: Zhigalenok Yaroslav , Abdimomyn Saken , Zhumadil Kaiyrgali , Lepikhin Maxim , Starodubtseva Alena , Kiyatova Marzhan , Shpigel Netanel , Malchik Fyodor
Published: August 2024

Supercapacitors are widely acknowledged as crucial devices for storing and converting electrical energy, alongside batteries and fuel cells. Their ability to rapidly charge and discharge, typically within seconds or even milliseconds, makes them ideal for high-power applications. This feature provides significant advantages for electric vehicles, such as regenerative braking and hill-climbing, where quick energy transfer is essential. To optimize the power performance of supercapacitor cells, it is essential to focus not only on the active material but also on the inactive components, including binders, conductive agents, and separators. The latter functions as an electronic insulating barrier between the cathode and the anode while facilitating optimal ionic transport across the cell. Therefore, particularly in high-power devices, selecting suitable separators is crucial to ensure fast charging kinetics and minimal cell resistance. Despite significant progress in developing high-power electrode materials, relatively few studies have been dedicated to membranes and their impact on the cell's electrochemical behavior. Herein, we provide a practical guide for choosing appropriate membranes for high-power supercapacitor applications. A comprehensive description of the main characterization methods for reliable evaluation of separators, alongside practical experimental examples, is given below. A special discussion is devoted to the evaluation of membrane impedance by various analytical approaches.
SPLEND1D, a reduced one-dimensional model to investigate the physics of plasma detachment
Authors: Février O. , Gorno S. , Theiler C. , Carpita M. , Durr-Legoupil-Nicoud G. , von Allmen M.
Published: August 2024

Studying the process of divertor detachment and the associated complex interplay of plasma dynamics and atomic physics processes is of utmost importance for future fusion reactors. While simplified analytical models exist to interpret the general features of detachment, they are limited in their predictive power, and complex two-dimensional (2D) or even three-dimensional (3D) codes are generally required to provide a self-consistent picture of the divertor. As an intermediate step, one-dimensional (1D) models of the scrape-off layer (SOL) can be particularly insightful as the dynamics are greatly simplified, while still self-consistently including various source and sink terms at play, as well as additional important effects such as flows. These codes can be used to shed light on the physics at play, to perform fast parameter scans, or to interpret experiments. In this paper, we introduce the SPLEND1D (Simulator of PLasma ENabling Detachment in 1D) code: a fast and versatile 1D SOL model. We present in detail the model that is implemented in SPLEND1D. We then employ the code to explore various elements of detachment physics for parameters typical of the Tokamak à Configuration Variable, including the atomic physics and other processes behind power and momentum losses, and explore the various hypotheses and free parameters of the model.
On the potential of ultrasonic time of flight instrumentation for the monitoring of thermal phenomena in laser powder bed fusion
Authors: Palla M. , Le Bourdais F. , Garandet J. P.
Published: August 2024

The present paper describes a proof of concept showing the ability of ultrasound time of flight measurements to complement existing temperature measurements in a laser powder bed fusion additive manufacturing process. To this end, two printers (a 3D Systems ProX DMP 320 and a Farsoon FS 271M) were instrumented with ultrasonic transducers, as well as with thermal cameras and thermocouples. The obtained results show that the time of flight signals can provide information that is both consistent and complementary with the data from the standard thermal camera and thermocouple systems. Such a conclusion is shown to be valid at both the macroscopic (i.e., whole fabrication) and the microscopic (individual layer melting and solidification) time scales. The present work shows that ultrasound time of flight data are a useful in situ diagnostic measurement. In addition, we discuss how it could be used for the validation of layer scale numerical models of the thermal phenomena during the printing process.
Exploring the nexus between thermodynamic phase transitions and geometric fractals through systematic lattice point classification
Authors: Ding Yonglong
Published: August 2024

Fractals are ubiquitous in the natural world, and their connection with phase transitions has been widely observed. This study investigates mechanisms of fractal formation from the perspective of phase transitions. A novel set of probability calculation methods is introduced to establish a direct link between fractals and phase transitions. Notably, in the Ising model, a specific category of boundary lattice points undergoes a phase transition when the associated weight reaches ∼0.4. The identified correlation between phase transitions and fractals suggests the emergence of fractal structures at this critical weight. This paper offers supporting evidence for this conclusion through the deliberate manipulation of the proposed probability-based method. This research contributes to a deeper understanding of the interplay between fractals and phase transitions, providing valuable insights for further exploration in diverse scientific domains.
Robust controller design and experimental validation based on bounded uncertainty for collaborative industrial robots
Authors: Cheng Hu , Zheng Hongmei , Zhen Shengchao , Liu Xiaoli , Chen Ye-Hwa
Published: August 2024

In this paper, derived from the proportional–derivative control and robust control, a novel practical robust control method based on a dynamic feedforward model is established by taking six-axis motion cooperative industrial robots as the research object. The nonlinear friction, parameter uncertainty, and external disturbance are taken into consideration while establishing the dynamic model of the cooperative industrial robot. The method includes a proportional–derivative control and a robust control. Lyapunov theory is used to analyze the proposed controller, and it is shown that this method can guarantee uniformly bounded and uniformly final bounded systems. Simulation and experiment results show that the proposed controller is better than proportional–integral–derivative control and mode-based proportional–derivative control in stability tracking performance and robustness. In addition, the CSPACE platform for rapid controller prototyping may reduce the arduous programming effort and offer a lot of ease for the trials.
Invited Article: The oxidation kinetics and mechanisms observed during ultra-high temperature oxidation of (HfZrTiTaNb)C and (HfZrTiTaNb)B2
Authors: Backman Lavina , Hunter Brett M. , Weaver Mark L. , Opila Elizabeth J.
Published: August 2024

Ultra-high temperature ceramics (UHTCs), most notably transition metal carbides and borides, exhibit melting temperatures exceeding 3000 °C, making them appropriate candidates to withstand the extreme temperatures (∼2000 °C) expected to occur at the leading edges of hypersonic vehicles. However, their propensity to react rapidly with oxygen limits their sustained application. The high entropy paradigm enables the exploration of novel UHTC compositions that may improve on the oxidation resistance of conventional refractory mono-carbides and -diborides. The oxidation kinetics of candidate high entropy group IV + V (HfZrTiTaNb)C and (HfZrTiTaNb)B2 materials were evaluated at 1500–1800 °C using Joule heating in one atmosphere 0.1%–1% oxygen/argon gas mixtures for times up to 15 min. Possible mechanisms based on the resulting complex time, temperature, and oxygen partial pressure dependencies are discussed. The carbides formed porous and intergranular oxides. Oxidation resistance was improved upon a continuous external scale formation. The diborides formed dense external scales and exhibited better oxidation resistance compared to the carbides. This improvement was attributed to the formation of liquid boria. Both compositions showed an unexpected reduction in material consumption at 1800 °C for all times tested, compared to results at lower temperatures. An in-depth analysis of the composition and morphology of the oxide scale and sub-surface regions for specimens tested at 1800 °C revealed that the formation of denser group IV-rich (Hf, Zr, Ti) oxides mitigated the formation of the otherwise detrimental liquid-forming group V (Ta, Nb) oxides, leading to the improved oxidation resistance.
Ionic Coulomb blockade controls the current in a short narrow carbon nanotube
Authors: Gibby William A. T. , Barabash Miraslau L. , Khovanov Igor A. , Luchinsky Dmitry G. , McClintock Peter V. E.
Published: August 2024

We use all-atom molecular dynamics simulations to investigate ionic conduction in a short, charged, single-wall carbon nanotube. They reveal ionic Coulomb blockade (ICB) oscillations in the current as a function of the fixed charge on the wall, and an associated occupancy staircase. Current peaks related to fluctuations around the 2 → 1 and 1 → 0 steps in occupancy are clearly resolved, in agreement with ICB theory. Current peaks were also observed at constant occupancy. These unpredicted secondary peaks are attributed to edge effects involving a remote knock-on mechanism; they are attenuated, or absent, for certain choices of model parameters. The key parameters of the system that underlie the current oscillations are estimated using ICB theory and the potential of the mean force. Future perspectives opened up by these observations are discussed.
Constriction requirement for nanoparticle crystallization in a non-thermal atmospheric pressure plasma
Authors: Papson Cameron , Basu Sankhadeep , Anthony Rebecca
Published: August 2024

Plasmas have emerged as among the most promising methods to synthesize nanoparticles, including from high-crystallization-temperature materials such as silicon. Recent work in the area of flow-through low-temperature plasma synthesis of nanoparticles has indicated that the assumptions of plug flow and diffuse plasma properties are not entirely supported by experimental evidence. Here, we report on an atmospheric pressure, non-thermal plasma reactor for silicon nanocrystal synthesis, together with our findings that the plasma is not diffuse but instead is a dynamic constricted discharge. Furthermore, we find that this constriction is dependent on the silane concentration in the reactor and also plays a role in nanoparticle crystallization. This work highlights the complexity of this process, and the need for further work to understand how nanoparticles are synthesized and crystallized in flow-through non-thermal plasma reactors.
Charging and propulsion of nano silicon in external electric and magnetic fields: Impact on the interstellar dust transport
Authors: Nayfeh Munir H. , Hoang Tuan , Nayfeh Ammar , Rezk Ayman
Published: August 2024

Observation of nanosilicon-based contributions to the interstellar nanodust is problematic because the indirect-bandgap of silicon makes its optical features wide, while carbon’s higher abundancy and ionization potential and the rising slope of extinction curves introduce heavy convolution. Recent macroscopic synthesis and charging of nanosilicon, the coming online of the Webb space telescope with unprecedented spectral resolution, and advances in modeling algorithms, light scattering, and fundamental atomistic computation may open opportunities for effective comparison between laboratory and space observation. Here, we study the transport of charged nanosilicon in electric/magnetic fields. We use high voltage across liquid colloids to charge and propel nanosilicon into external fields and imprint them on metal-coated substrates. We use absorption, luminescence, and light scattering in liquid, flight, and imprinted surfaces to study the field deflection of nanosilicon. We use the Mie/finite-difference time-domain theory to obtain scattering curves of nanosilicon and silica. Nanosilicon-based UV features near the 217.5-nm carbon bump are recorded and calculated using Time-Dependent Density Functional Theory (TDDFT) atomistic theory at 225, 280, and 153 nm resulting from bound–bound, and valence-continuum transitions, respectively. We also show that the constituents of silicates, oxygen and Mg and Fe metal ions, can attach to Si nanoparticles without interrupting luminescence, infrared, or UV signatures, respectively. Because charge defects allow nanosilicon transport over large distances via open B fields of solar holes as well as provide them with narrow “atomic-like” transitions, which are otherwise extended, sightlines with lower carbon and higher resolution afforded by Webb may allow the unmasking of Si-based features.
Electromagnetic Thomson parabola spectrometer for detection of fs laser-driven keV ions
Authors: Riedlinger Jan , Schwabe Lars Torben , Ibraimi Qëndresa , Pretzler Georg
Published: August 2024

Unconfined high-energy-density laser plasmas are known to emit broadband ion spectra in terms of species and their kinetic energy. The diagnostic of choice is often the Thomson parabola method, which is well-studied for the particle energies in the MeV range. In this work, a spectrometer is presented that is specifically designed to function down to energies of a few keV. Advancing into this regime requires an accurate knowledge of the spectrometer fields, which were precisely determined by simulations and measurements The dynamic range was substantially increased by adopting a compact electromagnet instead of a permanent one. We demonstrate how the field parameters can be chosen for obtaining exceptionally broad spectra while keeping the energy uncertainty minimal. Finally, the performance of the device is demonstrated for the ion emission of a carbon plasma ignited by sub-10-fs laser pulses.
Runaway electron fluid model extension in JOREK and ITER relevant benchmarks
Authors: Bandaru V. , Hoelzl M. , Artola F. J. , Vallhagen O. , Lehnen M. ,   JOREK Team
Published: August 2024

We present details of recent extensions of the runaway electron (RE) fluid model implemented in the fusion magnetohydrodynamics code JOREK [M. Hoelzl et al., Nucl. Fusion 61, 065001 (2021)] to include the effects of partially ionized impurity species and deuterium neutrals. The model treats the interaction of runaway electrons with the background plasma via current-coupling. The code is separately benchmarked using ITER (https://www.iter.org/) relevant scenarios, with the GO [G. Papp et al., Nucl. Fusion 53, 123017 (2013)] code in relation to runaway electron beam formation and with the DINA [Khayrutdinov and Lukash, J. Comp. Phys. 109(2), 193–201 (1993)] code in relation to simultaneous runaway beam formation and vertical plasma motion. Benchmark results show a decent agreement in both the cases, which are also discussed.
Heat jet approach for finite temperature atomic simulations of single-crystal silicon layers
Authors: Xia Xuewei , Zhang Lei , Liu Baiyili
Published: August 2024

An accurate and efficient heat bath method plays a key role in atomic simulations of the thermal and mechanical properties of single-crystal silicon. Here, focusing on the single-crystal silicon (111) layer, which is a crucial lattice structure commonly employed as a substrate for chips, we propose a heat jet approach for finite temperature atomic simulations of silicon layers. First, we formulate the linearized dynamic equations for the silicon atoms and calculate the dispersion relation and lattice wave solutions. Then, an appropriate matching boundary condition is chosen for designing the two-way boundary condition, which allows incoming waves to inject into the lattice system while eliminating boundary reflections. Combining the two-way boundary condition and phonon heat source, the heat jet approach for the silicon (111) layer is proposed. Numerical tests illustrate the accuracy and effectiveness of the heat jet approach in simultaneously resolving thermal fluctuations and controlling temperature. Furthermore, we simulate the propagation of a Gaussian hump at a given temperature with the heat jet approach compared to the Nosé–Hoover heat bath. Numerical results demonstrate that the heat jet approach can well describe the movement of large structural deformations among thermal fluctuations without boundary reflections.
Mechanisms of electrospray jet formation and atomized droplet motion in pulsed-jet mode
Authors: Wan H. , Liu P. J. , Qin F. , Wei X. G. , He G. Q. , Li W. Q.
Published: August 2024

Electrospray (ES) has attracted significant interest due to its advantages in generating uniform droplets and enabling controlled deposition. However, the complex interactions and droplet motion mechanisms between fluids and electric fields are still not well understood. Herein, this study presents a three-dimensional numerical model based on the volume of fluid and Lagrangian approaches to simulate the ES process in the pulsed jet mode. The model accurately captures the morphology and the atomization characteristics in the pulsed jet mode of ES. The effects of voltage and Reynolds number on the length of the non-atomized zone (including quasi-static Taylor cone, transition zone, and jet), diameter of the jet breakup, and atomization characteristics are discussed. Also, the mechanism of atomized droplets is revealed by analyzing the magnitudes of different types of forces imposing on the droplets in the electric field. The results indicate that higher Reynolds numbers lead to increased length of non-atomized zone and diameter of jet breakup, while the elevated voltages enhance atomization. Electric and Coulomb forces are, respectively, the dominant forces of forming the jet and expanding the atomization angle. Coulomb force increases the atomization angle, and electric field force increases the velocity of atomized droplets. Gravity and drag-force effects are relatively negligible throughout the atomization process. These findings contribute to a better understanding of the electrospray mechanisms and provide insights for optimizing electrospray applications.
Progress and challenges in the design of ITER’s polarimetric Thomson scattering diagnostic system
Authors: Bagnato F. , Bassan M. , Sirinelli A. , Vayakis G. , Kempenaars M. , Giudicotti L. , d’Isa F. A.
Published: August 2024

Polarimetric Thomson scattering (PTS) is a technique that allows for accurate measurements of electron temperature (Te) in very hot plasmas (Te > 10 keV, a condition expected to be regularly achieved in ITER). Under such conditions, the spectral region spanned by the TS spectrum is large and extends to low wavelengths, where the transmission of the collection optics decreases, available detectors are less efficient, and the high level of plasma background light perturbs the measurements. This work presents the recent developments in the design of a PTS system for ITER, along with the challenges posed by the complex machine design. The system performance is assessed for an updated geometry (with respect to previous publication), showing that, with a scattering angle θscat = 167°, the expected signal is strongly reduced. Potential alternatives are analyzed: (1) a system employing a different laser injection position, allowing for a more favorable scattering angle and (2) a recently proposed dual-polarization laser pulse technique. The latter is evaluated for the possible ITER geometry, again showing that a more favorable scattering angle is needed for a robust performance.
Atomic and micro-scale structural investigation of Bi/Cu and Bi–Cu-doped BCZT with dielectric properties
Authors: Kole Kanchan Kumar , Ghosh Jiten
Published: August 2024

In recent years, environment-friendly lead-free dopants-incorporated Ba-based perovskite oxides have found their potential applications in electronic devices due to their improved performances by modifying the crystal structures. In this study, BCZT [Ba0.9Ca0.1Zr0.1Ti0.9O3], Bi-doped BCZT [(Ba0.9Ca0.1)0.925Bi0.05Zr0.1Ti0.9O3], Cu-doped BCZT [Ba0.9Ca0.1(Zr0.1Ti0.9)0.997Cu0.003O3], and Bi–Cu both doped BCZT [(Ba0.9Ca0.1)0.925Bi0.05(Zr0.1Ti0.9)0.997Cu0.003O3] were prepared by conventional solid-state reaction method to study the effect of doping from microscopic and atomic point of view. XRD and Rietveld techniques are used to identify and quantify the phases, respectively. FTIR study confirmed the modification of the cell parameters due to doping, based on its composition. Raman spectroscopy is used to study the nature of symmetry presence in BCZT ceramics before and after doping. It reveals the presence of trace amount of orthorhombic symmetry with Tetragonal in all samples, as well as little cubic symmetry observed in BCZT-Bi and BCZT-BiCu. FESEM is used to study the surface morphology along with different grains in BCZT with doping. Localized structural distortion originated by dopants was investigated by the Atomic Pair Distribution Function (PDF) method. Aside from average structure, PDF gives information about localized structure within short-range zone, which is significantly modified, whereas long-range structure is almost similar. PDF shows the Raman-predicted orthorhombic phase is not exactly orthorhombic but the distorted tetragonal phase. Ultraviolet–visible (UV–vis) spectra show the bandgap energy increased after doping in BCZT. Dielectric measurement of all samples shows a high dielectric constant (>2000), and it is shown that vacancy in the crystal plays an important role in the dielectric behavior with frequency. The average and atomic–scale structure of Bi/Cu and Bi–Cu doped BCZT helped to understand the dielectric behavior for potential application of the barium titanate complex perovskites.
A thermochemical nonequilibrium model of CO2 plasma for studying flow-field properties of the spacecraft Mars Pathfinder
Authors: Yu Minghao , Hu Zhiqiang
Published: August 2024

Thermochemical nonequilibrium phenomena are key factors affecting the numerical simulation results of flow fields of Mars rover. In order to make clear the flow field properties of the Mars Pathfinder, a multi-physics numerical model including the Navier–Stokes equations, 11 species and 59 chemical reactions of CO2 plasma, and a four-temperature thermodynamic nonequilibrium model is established in this study. Numerical simulations on the thermal-chemical nonequilibrium flow fields of the Mars Pathfinder spacecraft are performed. The distributions of flow-field parameters such as temperature, pressure, Mach number, molar fractions of CO and CO2 around the Mars Pathfinder at different altitudes are obtained. It is found that there is a subsonic backflow at the rear of the Mars Pathfinder, resulting in slightly higher temperatures than other areas; after the shoulder, the pressure decreases rapidly; as the altitude decreases, the intensity of chemical reactions decreases, and the thermal-chemical nonequilibrium effects gradually weaken. Based on the chemical kinetic model of CO2 we proposed, the numerical simulation of the nonequilibrium flow field of the Mars Pathfinder spacecraft showed good predictive accuracy and application potential, providing reference value for subsequent studies on the thermal-chemical nonequilibrium effects of the Mars Pathfinder spacecraft.
A global adaptive discretization of velocity space for discrete velocity methods in predictions of rarefied and multi-scale flows
Authors: Chen Jianfeng , Liu Sha , Zhang Rui , Zhuo Congshan , Yang Yanguang , Zhong Chengwen
Published: August 2024

By introducing a discrete velocity space (DVS), deterministic methods in gas-kinetic theory, such as the discrete velocity method (DVM) and unified methods, can accurately capture complex nonequilibrium distribution functions and describe rarefied flow behaviors. However, describing high-speed flows with conventional Cartesian DVS is prohibitively costly due to the large number of discrete velocity points. Therefore, to enable deterministic solvers to handle complex, rarefied, and multi-scale flows effectively, a novel adaptive velocity space (AVS) is proposed. First, a global velocity mesh is intentionally adopted instead of a local velocity mesh to maintain a high level of DVS parallelism and facilitate extension to implicit algorithms. The global AVS is robust as it avoids the instability of information transformation between different cell-local AVS. Second, a new strategy is developed for reconstructing the distribution function in the tree-structured AVS, which is a low-order reconstruction with forced macroscopic conservation. This low-order reconstruction facilitates the direct value assignment between farther and child nodes, avoiding the derivative calculation of the distribution function (which is sometimes discontinuous). Additionally, the integration error of the low-order reconstruction is fixed by the forced macroscopic conservation. With these two important improvements, the proposed global AVS is then integrated into general DVM frameworks, such as the unified gas-kinetic scheme. Finally, a number of numerical tests are carried out to validate the proposed method, including steady and unsteady multi-scale flows.
SCN as a local probe of protein structural dynamics
Authors: Aydin Sena , Salehi Seyedeh Maryam , Töpfer Kai , Meuwly Markus
Published: August 2024

The dynamics of lysozyme is probed by attaching –SCN to all alanine residues. The one-dimensional infrared spectra exhibit frequency shifts in the position of the maximum absorption of 4 cm−1, which is consistent with experiments in different solvents and indicates moderately strong interactions of the vibrational probe with its environment. Isotopic substitution 12C → 13C leads to a redshift by −47 cm−1, which agrees quantitatively with experiments for CN-substituted copper complexes in solution. The low-frequency, far-infrared part of the protein spectra contains label-specific information in the difference spectra when compared with the wild type protein. Depending on the position of the labels, local structural changes are observed. For example, introducing the –SCN label at Ala129 leads to breaking of the α-helical structure with concomitant change in the far-infrared spectrum. Finally, changes in the local hydration of SCN-labeled alanine residues as a function of time can be related to the reorientation of the label. It is concluded that –SCN is potentially useful for probing protein dynamics, both in the high-frequency part (CN-stretch) and in the far-infrared part of the spectrum.
Design of radial interferometer–polarimeter for internal magnetic and density fluctuation measurements at multiple space–time scales in the National Spherical Torus Experiment-Upgrade (NSTX-U)
Authors: Chen J. , Brower D. L. , Li P. , Stratton B. , Prabhudesai G.
Published: August 2024

A Faraday-effect radial interferometer–polarimeter is designed for the National Spherical Torus Experiment-Upgrade (NSTX-U) to measure multiscale magnetic and density fluctuations critical to understanding fusion plasma confinement and stability, including those originating from magnetohydrodynamic instabilities, energetic particle-driven modes, and turbulence. The diagnostic will utilize the three-wave technique with 5 MHz bandwidth to simultaneously measure line-integrated magnetic and density fluctuations up to the ion-cyclotron frequency. Probe beams will be launched radially from the low-field side at the NSTX-U midplane, where the measured Faraday fluctuations mainly correspond to radial magnetic fluctuations that directly link to magnetic transport. A correlation technique will be employed to reduce the measurement noise to below 0.01° enabling detection of small amplitude fluctuations. Two toroidally displaced chords with 7° separation will be installed to measure toroidal mode numbers up to n = 25 for mode identification. Solid-state microwave sources operating at 321 μm (935 GHz) will be used to minimize the impact of the Cotton–Mouton effect.
Accurate estimation of the normalized mutual information of multidimensional data
Authors: Nagel Daniel , Diez Georg , Stock Gerhard
Published: August 2024

While the linear Pearson correlation coefficient represents a well-established normalized measure to quantify the inter-relation of two stochastic variables X and Y, it fails for multidimensional variables, such as Cartesian coordinates. Avoiding any assumption about the underlying data, the mutual information I(X, Y) does account for multidimensional correlations. However, unlike the normalized Pearson correlation, it has no upper bound (I ∈ [0, ∞)), i.e., it is not clear if say, I = 0.4 corresponds to a low or a high correlation. Moreover, the mutual information (MI) involves the estimation of high-dimensional probability densities (e.g., six-dimensional for Cartesian coordinates), which requires a k nearest-neighbor algorithm, such as the estimator by Kraskov et al. [Phys. Rev. E 69, 066138 (2004)]. As existing methods to normalize the MI cannot be used in connection with this estimator, a new approach is presented, which uses an entropy estimation method that is invariant under variable transformations. The algorithm is numerically efficient and does not require more effort than the calculation of the (un-normalized) MI. After validating the method by applying it to various toy models, the normalized MI between the Cα-coordinates of T4 lysozyme is considered and compared to a correlation analysis of inter-residue contacts.
New formulations for constructed polynomials and smoothness indicators of weighted essentially non-oscillatory schemes based on the forward-divided differences
Authors: Musa Omer , Huang Guoping
Published: August 2024

This paper introduces new formulations for the constructed polynomials and smoothness indicators within the weighted essentially non-oscillatory (WENO) scheme framework using the forward-divided differences approach. This technique transforms the interpolation polynomial and smoothness indicators into linear combinations of coefficients from different orders of forward-divided differences in the WENO polynomial reconstruction procedure. This approach simplifies the computation of higher-order versions of the global interpolation polynomial and smoothness indicators by adding extra terms to the lower-order version if previously calculated. As a result, this method simplifies the original expressions, reduces computational complexity, and improves computational efficiency. The new expressions are examined using an improved adaptive order WENO scheme, denoted as WENO-D5. This scheme computes a simple smoothness indicator for fifth-order linear reconstruction by linearly combining the existing smoothness indicators for third-order linear reconstructions. The WENO-D5 also employs new compact non-linear weights and global smoothness indicator. Several numerical experiments are performed to demonstrate the efficiency and performance of the considered fifth-order schemes. It is found that the forward-divided differences approach has improved the computational efficiency. The analysis also reveals that WENO-D5 consumed lower computational time than the adaptive order WENO [WENO-AO(5,3)] scheme while retaining the advantageous features of adaptive order schemes.
3He adsorbed on molecular hydrogen surfaces
Authors: Gordillo M. C. , Boronat J.
Published: August 2024

Using a diffusion Monte Carlo technique, we calculated the phase diagram of 3He adsorbed on a first solid layer of a molecular hydrogen isotope (H2, HD, and D2) on top of graphite. The results are qualitatively similar in all cases: a two-dimensional gas spanning from the infinite dilution limit to a second-layer helium density of 0.048 ± 0.004 Å−2. That gas is in equilibrium with a 7/12 commensurate structure, more stable than any incommensurate triangular solid of similar density. These findings are in reasonably good agreement with available experimental data.
Resolving plasmon-mediated high-order multiphoton excitation pathways in dolmen nanostructures using ultrafast nonlinear optical interferometry
Authors: Zhao Tian , Liu Xiaoying , Nepal Dhriti , Park Kyoungyeon , Vaia Richard , Nealey Paul , Knappenberger Kenneth L.
Published: August 2024

The multiphoton excitation pathways of plasmonic nanorod assemblies are described. By using dolmen structures formed from the directed assembly of three gold nanorods, plasmon-mediated three-photon excitation is resolved. These high-order multiphoton excitation channels were accessed by resonantly exciting a hybrid mode of the dolmen structure that was resonant with the 800-nm carrier wavelength of an ultrafast laser system. Rotation of the exciting field polarization to a non-resonant configuration did not generate third-order responses. Hence, the multiphoton excitation and resultant non-equilibrium electron distributions were generated by structure- and mode-selective excitation. Correlation between high-order and resonant plasmon excitation was achieved through sub-cycle time-resolved interferometric detection of incoherent nonlinear emission signals. The results illustrate the advantages of nonlinear optical interferometry and Fourier analysis for distinguishing plasmon-mediated processes from those that do not require plasmon excitation.
High-efficiency, broadband, and low-crosstalk 3D holography by multi-layer holographic-lens integrated metasurface
Authors: Sun Shuo , Li Jin , Li Xiaoxun , Huang Xiangyu , Zhang Yi , Chen Liang
Published: August 2024

Holographic display is considered the holy grail of photorealistic three-dimensional (3D) visualization technology because it can provide arbitrary wavefronts related to the essential visual cues of 3D images. Metasurfaces with exceptional high-pixel light modulation capability are increasingly favored for implementing high-quality 3D holography. However, current 3D metasurface holography always has some trade-offs among lots of algorithmic data, acceptable time, image quality, and structure complexity. Therefore, the development of a high-efficiency 3D metasurface holography device is still necessary to meet the increasing high space bandwidth product (SBP) of 3D technology. Here, based on the holographic-lens (HL) computer-generated hologram (CGH) algorithm, we experimentally demonstrate a new 3D metasurface holography device that integrates the 3D image phase cues and multiple layers of virtual lenses with different focal lengths, which exhibits significant capabilities in terms of ultra-high spatial pixel modulation and the generation of high-quality 3D holography characterized by high-efficiency, broadband response, low-crosstalk, and reduced acceptable time. The HL-CGH algorithm was efficiently integrated into parameter-optimized α-Si nanopillar meta-atoms, enabling enhanced visualization of 3D clues in a lens-free system. The prepared 3D HL-metasurface holography presented the presence of multiple depths of a 3D holographic image across a broad spectral range (400–900 nm), providing enhanced 3D visual cues. Our work provides a new perspective on designing metasurface-driven high-SBP 3D holography.
Virial relations for elongated plasmas in tokamaks: Analytical approximations and numerical calculations
Authors: Martynov A. A. , Pustovitov V. D.
Published: August 2024

Using the SPIDER code, three series of calculations of plasma equilibrium in a tokamak are performed—with low, medium, and high pressure. In each series, the cross section is purely elliptical with elongation varying from K=1 (circular plasma) to K=2.4. For these configurations, the integrals S1÷S3 defining the right-hand sides of the virial relations in Lao et al. [Nucl. Fusion 25, 1421 (1985)] are calculated. Their dependences on plasma parameters, elongation K of magnetic surfaces, and radial derivatives of K and Shafranov shift Δ are analyzed. The accuracy of analytical expressions for S1÷S3 proposed in Pustovitov [Phys. Plasmas 29, 092507 (2022)] is assessed.
Universal skin friction laws for turbulent flow in curved tubes
Authors: Ali Sk Zeeshan , Dey Subhasish
Published: August 2024

Delving into a century of turbulence research, we have long concentrated on skin friction laws by Blasius and Strickler, especially for straight-tube flows. Yet, a persistent question remains: Does skin friction in curved-tube flows possess universality? Addressing this enduring challenge, we present a phenomenological model unveiling universal laws governing turbulent skin friction, applicable to both rough and smooth curved-tube flows. We find that the skin friction coefficients, denoted by f, follow the inverse three-fourths law, f/α1/2 ∼ kα−3/4, and the inverse four-fifths law, f/α1/2 ∼ I−4/5, for rough and smooth flows, respectively, beyond certain threshold values. Here, α ≡ D/(2Rc) is the curvature ratio, D is the tube diameter, Rc is the radius of curvature, kα ≡ [(ks/D)−2α3]1/6 is the roughness-curvature number, ks is the roughness height, I ≡ (Reα2)1/4 is the Ishigaki number, and Re is the flow Reynolds number. Below their respective threshold limits, they recover the familiar skin friction laws for rough and smooth straight-tube flows. Our findings are primarily validated with an extensive dataset for smooth flow because of the data scarcity in rough flow. Supported by compelling skin friction data from smooth flow across various geometries—plane curved tube, helical tube, and toroid—gathered through experiments and simulations, our model serves as a potential bridge, connecting the theoretical and experimental realms of curved-tube turbulence.
Investigations of the adsorbed layer of polysulfone: Influence of the thickness of the adsorbed layer on the glass transition of thin films
Authors: Omar Hassan , Ahamadi Shayan , Hülagü Deniz , Hidde Gundula , Hertwig Andreas , Szymoniak Paulina , Schönhals Andreas
Published: August 2024

This work studies the influence of the adsorbed layer on the glass transition of thin films of polysulfone. Therefore, the growth kinetics of the irreversibly adsorbed layer of polysulfone on silicon substrates was first investigated using the solvent leaching approach, and the thickness of the remaining layer was measured with atomic force microscopy. Annealing conditions before leaching were varied in temperature and time (0–336 h). The growth kinetics showed three distinct regions: a pre-growth step where it was assumed that phenyl rings align parallel to the substrate at the shortest annealing times, a linear growth region, and a crossover from linear to logarithmic growth observed at higher temperatures for the longest annealing times. No signs of desorption were observed, pointing to the formation of a strongly adsorbed layer. Second, the glass transition of thin polysulfone films was studied in dependence on the film thickness using spectroscopic ellipsometry. Three annealing conditions were compared: two with only a tightly bound layer formed in the linear growth regime and one with both tightly bound and loosely adsorbed layers formed in the logarithmic growth regime. The onset thickness and increase in the glass transition temperature increases with annealing time and temperature. These differences were attributed to the distinct conformations of the formed adsorbed layers.
Resonant-enhanced multiphoton ionization of nitric oxide (NO) tagging velocimetry in a detonation-driven hypersonic shock tunnel
Authors: Chen Xiyu , Luo Kai , Wang Yejun , Wang Qiu , Li Pan , Zhao Wei
Published: August 2024

This Letter demonstrates the use of long-lifetime NO fluorescence for molecular tagging velocimetry (MTV) with (1 + 1) resonant-enhanced multiphoton ionization (REMPI) scheme, utilizing a single laser beam in a detonation-driven hypersonic shock tunnel. The Q1 branch of the NO A←X (0, 0) transition was excited using radiation near 226.256 nm. It was determined that (1 + 1) REMPI of NO generates long lifetime fluorescence, and this observation is consistent with the findings reported by Jiang et al. [Opt. Lett. 49, 1297–1300 (2024)] and Leonov et al. [Opt. Lett. 49, 426–429 (2024)]. Single-shot tagged lines at microsecond delay times were obtained in a Ma6.9 hypersonic freestream flow using a long focal length lens. The measured average velocity of 3477 m/s agrees well with the simulation result.
Unlocking therapeutic potential: the role of adamantane in drug discovery
Authors: Dane Chianna , Cumbers Grace A. , Allen Beau , Montgomery Andrew P. , Danon Jonathan J. , Kassiou Michael
Published: August 2024

The unique structural and physicochemical properties of adamantane and its derivatives have attracted considerable attention in the field of medicinal chemistry. Substituting phenyl rings for adamantane or its derivatives has provided a promising strategy to introduce lipophilicity and escape the ‘flat land’ of modern drug discovery. Additionally, the unique three-dimensional structure of adamantane facilitates the precise positioning of substituents allowing for a more effective exploration of drug targets. Evidently, we have seen an increased use of adamantane in pharmaceutically relevant molecules. The following Account highlights our group’s research in five drug discovery programs over the past 15 years showcasing the use of adamantane and its analogues in these studies.
B cell tolerance and autoimmunity: Lessons from repertoires
Authors: Deguine Jacques , Xavier Ramnik J.
Published: August 2024

Adaptive immune cell function is regulated by a highly diverse receptor recombined from variable germline-encoded segments that can recognize an almost unlimited array of epitopes. While this diversity enables the recognition of any pathogen, it also poses a risk of self-recognition, leading to autoimmunity. Many layers of regulation are present during both the generation and activation of B cells to prevent this phenomenon, although they are evidently imperfect. In recent years, our ability to analyze immune repertoires at scale has drastically increased, both through advances in sequencing and single-cell analyses. Here, we review the current knowledge on B cell repertoire analyses, focusing on their implication for autoimmunity. These studies demonstrate that a failure of tolerance occurs at multiple independent checkpoints in different autoimmune contexts, particularly during B cell maturation, plasmablast differentiation, and within germinal centers. These failures are marked by distinct repertoire features that may be used to identify disease- or patient-specific therapeutic approaches.