bluuebunny/crossref_metadata_2025 huggingface dataset:
On Monami modes and scales of a flexible vegetation array in a laminar boundary layer
Authors: Ni Jinyuan , Ji Chunning , Xu Dong , Zhang Xing , Liang Dongfang
Published: July 2023

Flexible aquatic vegetation exists widely in nature and serves multiple hydro-environmental functions mainly through fluid–structure interactions. The waving motion of vegetation arrays, known as Monami, is predominantly governed by Kelvin–Helmholtz (KH) instability, and its characteristic scales, such as wave height and wavelength, are still being explored. In this paper, the interactions between a large array of flexible vegetations and a laminar boundary-layer flow are investigated using direct numerical simulation. The parameters used are the Reynolds number Re = 400, mass ratio β = 1.0, bending rigidity γ = 0.04–0.22, and gap distance d = 0.4–1.6. A low frequency in Monami is found to be related to the fluctuation frequency of the onset position of the KH instability, which leads to the identification of four different Monami modes: regular Monami, quasi-regular Monami A, quasi-regular Monami B, and irregular Monami. The influences of the bending rigidity and gap distance on the Monami modes, KH instability onset position, and Monami characteristic scales are discussed. It was found that the causes of spatial and temporal variations in the characteristic scales of Monami vary depending on the mode. In the regular Monami mode, these variations result from the evolution of the KH vortex. In the quasi-regular Monami A mode, they are strongly affected by the shifting of the onset position of the KH instability. In the other two modes, these variations are caused by a combination of the fluctuation in the KH instability onset position and the complex interaction between vortices.
A phase-locked transit time oscillator operated with low external guiding magnetic field
Authors: Song Hao , He Juntao , Ling Junpu , Wang Lei , Song Lili
Published: July 2023

A phase-locked coaxial transit time oscillator is designed for microwave sources with a small volume and low magnetic field in high-power microwave coherent combining. The oscillator achieves controlled output phase through pre-modulation of electron beams. To improve the phase-locked performance with low magnetic fields, a reentrant input cavity is used to ensure the stability and uniformity of the electric field. Electric field uniformity of the buncher and extractor is also improved. To reduce the device volume, a reflector with pre-modulation function is used to reduce the axial size of the device. Particle-in-cell simulation shows that 5 kW input power is sufficient to lock-in a 610 MW output microwave, with a conversion efficiency of 40.6% at 0.66 T. The input power ratio reaches −50.8 dB. Simulation results demonstrate that the device can still achieve phase locking with a magnetic field as low as 0.5 T.
Revealing system dimension from single-variable time series
Authors: Börner Georg , Haehne Hauke , Casadiego Jose , Timme Marc
Published: July 2023

Complex and networked dynamical systems characterize the time evolution of most of the natural and human-made world. The dimension of their state space, i.e., the number of (active) variables in such systems, arguably constitutes their most fundamental property yet is hard to access in general. Recent work [Haehne et al., Phys. Rev. Lett. 122, 158301 (2019)] introduced a method of inferring the state space dimension of a multi-dimensional networked system from repeatedly measuring time series of only some fraction of observed variables, while all other variables are hidden. Here, we show how time series observations of one single variable are mathematically sufficient for dimension inference. We reveal how successful inference in practice depends on numerical constraints of data evaluation and on experimental choices, in particular the sampling intervals and the total duration of observations. We illustrate robust inference for systems of up to N=10 to N=100 variables by evaluating time series observations of a single variable. We discuss how the faithfulness of the inference depends on the quality and quantity of collected data and formulate some general rules of thumb on how to approach the measurement of a given system.
What do far-infrared spectra of solitary water in “water-in-solvent” systems reveal about water’s solvation and dynamics?
Authors: Palchowdhury Sourav , Mukherjee Kallol , Maroncelli Mark
Published: July 2023

Classical molecular dynamics simulations of water in ionic and dipolar solvents were used to interpret the far-infrared (FIR) rotation/libration spectra of “solitary water” in terms of water’s rotational dynamics and interactions with solvents. Seven solvents represented by nonpolarizable all-atom force fields and a series of idealized variable-charge solvents were used to span the range of solvent polarities (hydrogen bonding) studied experimentally. Simulated spectra capture the solvent dependence observed, as well as the relationship between the frequencies of water libration (νL) and OH stretching bands (νOH). In more strongly interacting solvents, simulated νL are ∼20% higher than those of experiment. In all solvents, the simulated spectra are composites of rotational motions about the two axes perpendicular to water’s dipole moment, and the different frequencies of these two motions are responsible for the breadth of the libration band and the bimodal shape observed in halide ionic liquids. Simulations overestimate the separation of these two components in most solvents. The character of water rotational motions changes markedly with solvent polarity, from quasi-free rotation in nonpolar and weakly polar solvents to highly constrained libration in strongly hydrogen bonding environments. The changeover to librational motions dominating the spectrum occurs between solvents such as benzene (νL ∼ 250 cm−1) and acetonitrile (νL ∼ 400 cm−1). For solvents in the latter category, the mean frequency of the experimental FIR band provides a direct measure of mean-squared torques and, therefore, force constants associated with interactions constraining water’s librational motion.
Bifurcation and stability of a diffusive predator–prey model with the fear effect and time delay
Authors: Wang Huatao , Zhang Yan , Ma Li
Published: July 2023

The predator–prey system can induce wealth properties with fear effects. In this paper, we propose a diffusive predator–prey model where the influence of fear effects and time delay is considered, under the Dirichlet boundary condition. It follows from the Lyapunov–Schmidt reduction method that there exists a non-homogeneous steady-state solution of the system and the specific expressions are also given. By the aid of bifurcation theory and eigenvalue theory, we also investigate the existence/non-existence and the stability of Hopf bifurcation under three different conditions of bifurcation parameters. Furthermore, the effects of the fear on population density, stability, and Hopf bifurcation are also considered and the results show that the increase of fear effects will reduce the population density, and Hopf bifurcation is more likely difficult to undergo as k increases under some conditions.
High mobility electron gas with quasi-two-dimensional characteristics at the interface of Cr2O3/SrTiO3 heterostructures
Authors: Li Shuang-Shuang , Wang Zhao-Cai , Ying Jing-Shi , Zhang Ying , Chen Lei , Ye Mao , Ke Shan-Ming , Zhao Weiyao , Zheng Ren-Kui
Published: July 2023

Two-dimensional electron gas is precisely confined at the interface of insulating oxide thin films and substrates, e.g., LaAlO3/SrTiO3(STO) and, thus, shows 2D electronic transport features. Here, we report a high mobility electron state at the interface of a Cr2O3 film and a STO substrate, which is realized by depositing a Cr film onto a STO (111) substrate in high vacuum (1 × 10−10 mbar) using molecular beam epitaxy. At a substrate temperature of 700 °C, the deposited Cr films capture oxygen atoms from STO substrates, resulting in the formation of an insulating Cr2O3 layer and an oxygen-deficient STO layer. Due to the presence of high mobility electrons [1.5 × 104 cm2V−1 s−1 at 1.8 K] at the Cr2O3/STO interface, both out-of-plane and in-plane Shubnikov–de Haas oscillations are observed at low temperatures (<3 K), which suggests that the highly conducting electron gas has extended into the STO bulk along the thickness direction with a certain depth to allow electrons to complete the cyclotron motion.
Experimental and numerical investigation on the wake flow and vortex shedding of a rotating circular cylinder
Authors: Liu Jianhan , Ma Wenyong , Jin Longqian , Liu Xinyue , Li Tianxu
Published: July 2023

When fluid passes through a still cylinder, alternate shedding vortices are formed on the two sides of the cylinder in the wake. Regarding a rotating circular cylinder, the rotation can affect the wake flow and vortex shedding pattern. To investigate the wake flow and surface pressure characteristics of a rotating cylinder at different rotational speeds, wind tunnel tests and numerical simulation methods through Fluent were used. The dimensionless rotational speed was discussed for its impact on the vortex shedding intensity and pattern. Additionally, the correlation between the cylinder surface wind pressure and the vortex shedding pattern was analyzed. The results of this study provide useful insights into the mechanisms underlying the vortex shedding phenomenon and the effects of rotational speed on the wake flow and surface pressure of a rotating cylinder. The results show that an increase in the dimensionless rotational speed will change the characteristics of the wind pressure distribution, leading to the variation in aerodynamic coefficients. On the other hand, the vortex shedding characteristics of the wake flow will also be affected, with changes in the vortex shedding pattern and direction, thereby changing the characteristics of the wake deviation angle and correlation. Based on the analysis of wake flow speed power spectrum characteristics and the Reynolds number effect, the mechanism of the vortex shedding change caused by flow transitions is speculated and verified by numerical simulation of the vorticity field.
Time-resolved photo-magnetic switching of bubble domains in ferrimagnetic garnets
Authors: Zalewski T. , Maziewski A. , Stupakiewicz A.
Published: July 2023

We investigate the single-domain switching of magnetization with a femtosecond laser pulse in Co-doped iron garnet films using time-resolved magneto-optical imaging. This switching regime is achieved with a pump fluence that is two times lower than the fluence required for multi-domain switching. We observed the picoseconds magnetization dynamics of switching in a single bubble domain with a diameter of a few micrometers by tuning the pump laser fluence. This may provide opportunities for cold photo-magnetic recording in magnetic bits approaching the nano-size scale.
Voltage-gated field-free spin–orbit torque switching in Pt/Co/Ir/MgO wedged structures
Authors: Li Yang , Zhao Xiaotian , Liu Wei , Wu Jinxiang , Liu Long , Song Yuhang , Ma Jun , Zhang Zhidong
Published: July 2023

The ability to efficiently manipulate magnetization is of great significance for practical applications of spin–orbit torque (SOT) devices. In this study, we report the voltage-controlled, field-free SOT switching in perpendicular magnetized Pt/Co/Ir/MgO structures with wedge iridium interlayers. The insertion of a thin iridium interlayer at ferromagnet/oxide can significantly reduce the perpendicular magnetic anisotropy depending on the Ir thickness. The wedging of the iridium layer breaks lateral structural symmetry, resulting in deterministic switching without the assistance of in-plane magnetic fields. In such a structure, the SOT critical switching currents are remarkably decreased by 29% when a positive 6 V gate voltage is applied. Further quantitative analysis shows that multiple factors contribute to the decrease in switching currents, including a 23% reduction in magnetic anisotropy energy, a reduction in nucleation field, and a minor enhancement in damping-like torque under gate voltage. Moreover, the probabilistic hindrance that gate voltage poses to field-free switching is revealed by the decrease in current-induced perpendicular effective fields from symmetry-breaking. Our research shows that energy-efficient SOT switching can be controlled by gating and offers insight into the mechanism behind voltage-gated SOT switching.
A comparative study on the different energy supply modes for a micro-cathodic arc thruster
Authors: Ji Tianyuan , Wei Liqiu , Wang Lu , Li Ji , Zhao Yongguo , Ren Ziying , Liang Tiance , Ma Haochen , Li Hong , Zhu Ximing , Ding Yongjie
Published: July 2023

The energy supply mode of a micro-cathodic arc thruster (μ-CAT) was adjusted based on the charge and discharge characteristics of the energy storage element, and the cathode discharge characteristics of μ-CAT were studied under different energy supply modes. We applied an electrical method to measure the discharge characteristics of μ-CAT, with an enhanced intensified charge coupled device spectrum detector to measure the plasma parameters of μ-CAT, allowing analysis of the internal logic among thruster plasma parameters, arc discharge characteristics, and thruster energy supply mode. The mechanisms of μ-CAT were analyzed and characteristics of accumulated discharge, energy distribution, and ion velocity distribution of thruster were compared under different energy supply modes to obtain the effect of the energy supply mode on the discharge characteristics of the interelectrode of μ-CAT. The results show that the energy supply mode of μ-CAT affected the ionization characteristics and ionization stability of the micro-cathodic arc thruster, causing a multistage ionization difference in the cathode metal target. This would not only affect the propulsion performance of the thruster, but also affect the change of the number of particles in the cathode region in a single discharge cycle.
Faraday effect in collisional magnetized plasmas
Authors: Keenan Brett D. , Stark David J.
Published: July 2023

Faraday rotation is a valuable diagnostic tool for investigating laboratory and astrophysical plasmas, but it has almost exclusively been treated in the collisionless limit (despite the non-negligible role of Coulomb collisions in many laboratory plasmas). Here, we show that Faraday rotation can occur in collisional plasmas and that the usual effect is curiously altered by collisions. Namely, an initially linearly polarized light wave—propagating parallel to a uniform magnetic field—becomes elliptically polarized in the collisional plasma, and collisional absorption of the wave also occurs. Moreover, the ellipticity and rotation angle are quantifiably sensitive to the fidelity of the collisional transport coefficients. As we will demonstrate with particle-in-cell EPOCH simulations, these effects offer a stringent diagnostic tool for benchmarking multi-scale plasma simulation codes.
Fluctuation-driven instability of nanoscale liquid films on chemically heterogeneous substrates
Authors: Zhao Chengxi , Zhang Zhao , Si Ting
Published: July 2023

The instability and dewetting of bounded liquid films at the nanoscale are shown to strongly depend on thermal fluctuations. In this work, this fluctuation-driven instability of films on a chemically heterogeneous substrate is investigated both by a stochastic lubrication equation (SLE), which models thermal fluctuations with white noise, and by molecular dynamics (MD). Linear instability analysis for the SLE, considering slip and intermolecular forces of the heterogeneous substrates, is employed to derive a spectrum of the thermal capillary waves and their corresponding interface roughness, which are then quantitatively confirmed by numerical solutions for the SLE and MD. The fluctuation-driven instability is found to be enhanced by the slip and intermolecular forces, with the latter becoming dominant toward the final rupture. Moreover, the results suggest that a heterogeneous substrate can be approximated as a homogeneous one with effective (averaged) slip lengths and Hamaker constants for the intermolecular forces. The gradients of the slip and intermolecular forces due to the heterogeneities are shown not to affect the instability significantly.
“One stone three birds” plasma engraving strategy to boost the hydrogen evolution reaction activity of layered double hydroxides
Authors: Yang Yanqiu , Wang Zhengzhao , Yan Ping , Yu Xin-Yao
Published: July 2023

Possessing large specific surface areas and rich metal redox sites, layered double hydroxides (LDHs) are potentially suitable oxygen evolution reaction catalysts. It is a pity that they usually show poor hydrogen evolution reaction (HER) activity on account of the limited conductivity and deficient active sites. Taking NiFe LDH nanosheets as an example, we develop a “one stone three birds” plasma engraving strategy to enhance the HER activity of NiFe LDH. The “three birds,” including the reduction of Ni2+ to Ni nanoparticles (Ni NPs), generation of more oxygen vacancies (Ov), and exfoliation of nanosheets into much thinner ones, can obviously improve the conductivity and active sites of NiFe LDH. The plasma processing can also enhance water adsorption and accelerate the Volmer step during HER. As expected, the plasma-engraved NiFe LDH (PEH) exhibits enhanced HER activity with a low overpotential of 22 mV at 10 mA cm−2 and a small Tafel slope of 38 mV dec−1 in 1 M KOH, much better than NiFe LDH (202 mV, 145 mV dec−1). By combining optical emission spectroscopy diagnosis and structural/electrochemical characterizations, the relationship among the electron excitation temperature (Texc) in plasma, the amount of Ni NPs and Ov in PEH, and the HER activity of PEH is established. Excitingly, the PEH also displays splendid HER activity in both alkaline real seawater and overall water splitting.
Analysis of turbulent mixing in a methane–oxygen recessed injector for space propulsion
Authors: Martinez-Sanchis Daniel , Sternin Andrej , Jocher Agnes , Haidn Oskar
Published: July 2023

Turbulent mixing in a methane–oxygen recessed injector is studied using direct numerical simulations. The operating point is chosen to be fuel-rich and at high pressure to recreate a representative environment for space propulsion applications. The results are used to investigate the transport of the turbulent mixture fraction statistics and the validity of conventional transport models. It is observed that molecular diffusion is only relevant near the boundary layer of the injection recess cavity and at the recirculation zone. Moreover, turbulent mixing in the axial direction is negligible as radial turbulent diffusion dominates. Radial turbulent diffusion near injection is driven by Kelvin–Helmholtz Instabilities (KHI) manifesting at large scales in the order of the injector geometry. The dominance of this process over microscale mixing originates negative turbulent diffusion, which produces a mixture resegregation and the appearance of lean pockets far from the oxidizer injection plane. Gradient models display poor capabilities for the prediction of this sort of phenomena. Closure models for the turbulent mixing transport terms are proposed and evaluated. An anisotropic gradient model is devised, providing performance improvements within the recess cavity and the recirculation region. In addition, a novel filtered Reynolds-averaged Navier Stokes approach based on the mixing state is proposed. This new methodology shows excellent prediction capabilities in the regions dominated by KHI, accurately predicting negative turbulent diffusivity. The challenges associated with this model are commented on, and strategies to enable its application are proposed.
Comparison and evaluation of dimensionality reduction techniques for the numerical simulations of unsteady cavitation
Authors: Zhang Guiyong , Wang Zihao , Huang Huakun , Li Hang , Sun Tiezhi
Published: July 2023

In the field of fluid mechanics, dimensionality reduction (DR) is widely used for feature extraction and information simplification of high-dimensional spatiotemporal data. It is well known that nonlinear DR techniques outperform linear methods, and this conclusion may have reached a consensus in the field of fluid mechanics. However, this conclusion is derived from an incomplete evaluation of the DR techniques. In this paper, we propose a more comprehensive evaluation system for DR methods and compare and evaluate the performance differences of three DR methods: principal component analysis (PCA), isometric mapping (isomap), and independent component analysis (ICA), when applied to cavitation flow fields. The numerical results of the cavitation flow are obtained by solving the compressible homogeneous mixture model. First, three different error metrics are used to comprehensively evaluate reconstruction errors. Isomap significantly improves the preservation of nonlinear information and retains the most information with the fewest modes. Second, Pearson correlation can be used to measure the overall structural characteristics of the data, while dynamic time warping cannot. PCA performs the best in preserving the overall data characteristics. In addition, based on the uniform sampling-based K-means clustering proposed in this paper, it becomes possible to evaluate the local structural characteristics of the data using clustering similarity. PCA still demonstrates better capability in preserving local data structures. Finally, flow patterns are used to evaluate the recognition performance of flow features. PCA focuses more on identifying the major information in the flow field, while isomap emphasizes identifying more nonlinear information. ICA can mathematically obtain more meaningful independent patterns. In conclusion, each DR algorithm has its own strengths and limitations. Improving evaluation methods to help select the most suitable DR algorithm is more meaningful.
Predicting substantive biomedical citations without full text
Authors: Hoppe Travis A. , Arabi Salsabil , Hutchins B. Ian
Published: July 2023

Insights from biomedical citation networks can be used to identify promising avenues for accelerating research and its downstream bench-to-bedside translation. Citation analysis generally assumes that each citation documents substantive knowledge transfer that informed the conception, design, or execution of the main experiments. Citations may exist for other reasons. In this paper, we take advantage of late-stage citations added during peer review because these are less likely to represent substantive knowledge flow. Using a large, comprehensive feature set of open access data, we train a predictive model to identify late-stage citations. The model relies only on the title, abstract, and citations to previous articles but not the full-text or future citations patterns, making it suitable for publications as soon as they are released, or those behind a paywall (the vast majority). We find that high prediction scores identify late-stage citations that were likely added during the peer review process as well as those more likely to be rhetorical, such as journal self-citations added during review. Our model conversely gives low prediction scores to early-stage citations and citation classes that are known to represent substantive knowledge transfer. Using this model, we find that US federally funded biomedical research publications represent 30% of the predicted early-stage (and more likely to be substantive) knowledge transfer from basic studies to clinical research, even though these comprise only 10% of the literature. This is a threefold overrepresentation in this important type of knowledge flow.
Slingshot homolog-1–mediated Nrf2 sequestration tips the balance from neuroprotection to neurodegeneration in Alzheimer’s disease
Authors: Cazzaro Sara , Woo Jung-A A. , Wang Xinming , Liu Tian , Rego Shanon , Kee Teresa R. , Koh Yeojung , Vázquez-Rosa Edwin , Pieper Andrew A. , Kang David E.
Published: July 2023

Oxidative damage in the brain is one of the earliest drivers of pathology in Alzheimer’s disease (AD) and related dementias, both preceding and exacerbating clinical symptoms. In response to oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) is normally activated to protect the brain from oxidative damage. However, Nrf2-mediated defense against oxidative stress declines in AD, rendering the brain increasingly vulnerable to oxidative damage. Although this phenomenon has long been recognized, its mechanistic basis has been a mystery. Here, we demonstrate through in vitro and in vivo models, as well as human AD brain tissue, that Slingshot homolog-1 (SSH1) drives this effect by acting as a counterweight to neuroprotective Nrf2 in response to oxidative stress and disease. Specifically, oxidative stress-activated SSH1 suppresses nuclear Nrf2 signaling by sequestering Nrf2 complexes on actin filaments and augmenting Kelch-like ECH-associated protein 1 (Keap1)–Nrf2 interaction, independently of SSH1 phosphatase activity. We also show that
Ssh1
elimination in AD models increases Nrf2 activation, which mitigates tau and amyloid-β accumulation and protects against oxidative injury, neuroinflammation, and neurodegeneration. Furthermore, loss of
Ssh1
preserves normal synaptic function and transcriptomic patterns in tau
P301S
mice. Importantly, we also show that human AD brains exhibit highly elevated interactions of Nrf2 with both SSH1 and Keap1. Thus, we demonstrate here a unique mode of Nrf2 blockade that occurs through SSH1, which drives oxidative damage and ensuing pathogenesis in AD. Strategies to inhibit SSH1-mediated Nrf2 suppression while preserving normal SSH1 catalytic function may provide new neuroprotective therapies for AD and related dementias.
Migration and division in cell monolayers on substrates with topological defects
Authors: Kaiyrbekov Kurmanbek , Endresen Kirsten , Sullivan Kyle , Zheng Zhaofei , Chen Yun , Serra Francesca , Camley Brian A.
Published: July 2023

Collective movement and organization of cell monolayers are important for wound healing and tissue development. Recent experiments highlighted the importance of liquid crystal order within these layers, suggesting that +1 topological defects have a role in organizing tissue morphogenesis. We study fibroblast organization, motion, and proliferation on a substrate with micron-sized ridges that induce +1 and −1 topological defects using simulation and experiment. We model cells as self-propelled deformable ellipses that interact via a Gay–Berne potential. Unlike earlier work on other cell types, we see that density variation near defects is not explained by collective migration. We propose instead that fibroblasts have different division rates depending on their area and aspect ratio. This model captures key features of our previous experiments: the alignment quality worsens at high cell density and, at the center of the +1 defects, cells can adopt either highly anisotropic or primarily isotropic morphologies. Experiments performed with different ridge heights confirm a prediction of this model: Suppressing migration across ridges promotes
higher
cell density at the +1 defect. Our work enables a mechanism for tissue patterning using topological defects without relying on cell migration.
Fundamental limits in structured principal component analysis and how to reach them
Authors: Barbier Jean , Camilli Francesco , Mondelli Marco , Sáenz Manuel
Published: July 2023

How do statistical dependencies in measurement noise influence high-dimensional inference? To answer this, we study the paradigmatic spiked matrix model of principal components analysis (PCA), where a rank-one matrix is corrupted by additive noise. We go beyond the usual independence assumption on the noise entries, by drawing the noise from a low-order polynomial orthogonal matrix ensemble. The resulting noise correlations make the setting relevant for applications but analytically challenging. We provide characterization of the Bayes optimal limits of inference in this model. If the spike is rotation invariant, we show that standard spectral PCA is optimal. However, for more general priors, both PCA and the existing approximate message-passing algorithm (AMP) fall short of achieving the information-theoretic limits, which we compute using the replica method from statistical physics. We thus propose an AMP, inspired by the theory of adaptive Thouless–Anderson–Palmer equations, which is empirically observed to saturate the conjectured theoretical limit. This AMP comes with a rigorous state evolution analysis tracking its performance. Although we focus on specific noise distributions, our methodology can be generalized to a wide class of trace matrix ensembles at the cost of more involved expressions. Finally, despite the seemingly strong assumption of rotation-invariant noise, our theory empirically predicts algorithmic performance on real data, pointing at strong universality properties.
Surviving through the COVID-19 Pandemic: The Case of iFLY Queenstown
Authors: Malthus Tessa K. , Lee Craig , Finkler Wiebke , Walker Lloyd , Carr Neil
Published: July 2023

The case study discusses the initiatives a tourism business in New Zealand implemented to survive during the COVID-19 pandemic and the business’ plans towards a post-COVID-19 recovery. iFLY Queenstown is a popular tourism business in Queenstown, New Zealand, offering indoor skydiving experiences. Due to the COVID-19 pandemic and ensuing lockdowns restricting movement, business was severely disrupted for iFLY Queenstown and the wider New Zealand tourism industry. Despite this, iFLY Queenstown was one of the few businesses that survived and thrived during this disruptive period. This case study discusses the initiatives the Director of iFLY Queenstown, Mr Matt Wong, implemented to ensure his business’ survival during the COVID-19 pandemic and his plans to lead his business towards a post-COVID-19 recovery. The information for this case study is based on a series of one-to-one interviews conducted with Mr Wong during and after the New Zealand border closure driven by the COVID-19 pandemic. This case study is based on a variety of material produced by Culture Ready (Available at:
https://cape.org.nz/culture-ready/
), a programme designed to raise cultural awareness among tourism operators in New Zealand.

Information

© The Authors 2023
TLR7/8 stress response drives histiocytosis in SLC29A3 disorders
Authors: Shibata Takuma , Sato Ryota , Taoka Masato , Saitoh Shin-Ichiroh , Komine Mayumi , Yamaguchi Kiyoshi , Goyama Susumu , Motoi Yuji , Kitaura Jiro , Izawa Kumi , Yamauchi Yoshio , Tsukamoto Yumiko , Ichinohe Takeshi , Fujita Etsuko , Hiranuma Ryosuke , Fukui Ryutaro , Furukawa Yoichi , Kitamura Toshio , Takai Toshiyuki , Tojo Arinobu , Ohtsuki Mamitaro , Ohto Umeharu , Shimizu Toshiyuki , Ozawa Manabu , Yoshida Nobuaki , Isobe Toshiaki , Latz Eicke , Mukai Kojiro , Taguchi Tomohiko , Hemmi Hiroaki , Akira Shizuo , Miyake Kensuke
Published: July 2023

Loss-of-function mutations in the lysosomal nucleoside transporter SLC29A3 cause lysosomal nucleoside storage and histiocytosis: phagocyte accumulation in multiple organs. However, little is known about the mechanism by which lysosomal nucleoside storage drives histiocytosis. Herein, histiocytosis in Slc29a3−/− mice was shown to depend on Toll-like receptor 7 (TLR7), which senses a combination of nucleosides and oligoribonucleotides (ORNs). TLR7 increased phagocyte numbers by driving the proliferation of Ly6Chi immature monocytes and their maturation into Ly6Clow phagocytes in Slc29a3−/− mice. Downstream of TLR7, FcRγ and DAP10 were required for monocyte proliferation. Histiocytosis is accompanied by inflammation in SLC29A3 disorders. However, TLR7 in nucleoside-laden splenic monocytes failed to activate inflammatory responses. Enhanced production of proinflammatory cytokines was observed only after stimulation with ssRNAs, which would increase lysosomal ORNs. Patient-derived monocytes harboring the G208R SLC29A3 mutation showed enhanced survival and proliferation in a TLR8-antagonist-sensitive manner. These results demonstrated that TLR7/8 responses to lysosomal nucleoside stress drive SLC29A3 disorders.
Enhancing students’ understanding of vectors through personalized adaptive learning
Authors: Dubey Archana , Barniol Pablo
Published: July 2023

In introductory college physics courses, it is important that students have a thorough understanding of vectors since several topics depend on vectors. When the test of understanding of vectors (TUV) was administered to the students completing the algebra-based College Physics I course, it was found that students had considerable difficulties in certain vector concepts. To overcome these difficulties, the question-bank for personalized adaptive learning (PAL) was modified. These modifications were implemented in a later semester for the students of the same course. In the current work, we present students’ performance on 12 questions on TUV for two semesters with a focus on improvement in students’ performance on graphic representation and determination of direction and magnitude of a vector presented in unit vector notation, understanding of graphical methods for vector addition, subtraction and multiplication of a vector by a negative scalar. This study presents the development of questions in PAL assignments which may be beneficial for the teaching community.
Tunable electrical contact properties in two-dimensional van der Waals V2C/MoSi2N4 heterostructures
Authors: Zhu Xiangjiu , Jiang Hongxing , Zhang Yukai , Wang Dandan , Yang Lihua , Fan Lin , Chen Yanli , Qu Xin , Liu Yang
Published: July 2023

Two-dimensional MoSi2N4 is a member of the emerging 2D MA2N4 family, which has been synthesized in experiments, recently. Herein, we conduct a first-principles investigation to study more about the atomic and electronic structures of V2C/MoSi2N4 (1T-phase) van der Waals heterostructures (vdWHs) and interlayer distance and an external perpendicular electric field change their tunable electronic structures. We demonstrate that the V2C/MoSi2N4 vdWHs contact forms n-type Schottky contact with an ultralow Schottky barrier height of 0.17 eV, which is beneficial to enhance the charge injection efficiency. In addition, the electronic structure and interfacial properties of V2C/MoSi2N4 vdWHs can be transformed from n-type to p-type ShC through the effect of layer spacing and electric field. At the same time, the transition from ShC to OhC can also occur by relying on the electric field and different interlayer spacing. Our findings could give a novel approach for developing optoelectronic applications based on V2C/MoSi2N4 vdW heterostructures.
Modular assembly of microswimmers with liquid compartments
Authors: Hu Minghan , Shen Xueting , Tran Daniel , Ma Zhongqi , Isa Lucio
Published: July 2023

Artificial microswimmers, i.e. colloidal scale objects capable of self-propulsion, have garnered significant attention due to their central role as models for out of equilibrium systems. Moreover, their potential applications in diverse fields such as biomedicine, environmental remediation, and materials science have long been hypothesized, often in conjunction with their ability to deliver cargoes to overcome mass transport limitations. A very efficient way to load molecular cargoes is to disperse them in a liquid compartment, however, fabricating microswimmers with multiple liquid compartments remains a significant challenge. To address this challenge, we present a modular fabrication platform that combines microfluidic synthesis and sequential capillarity-assisted particle assembly (sCAPA) for microswimmers with various liquid compartments. We demonstrate the synthesis of monodisperse, small polymer-based microcapsules (Ø = 3–6 μm) with different liquid cargoes using a flow-focusing microfluidic device. By employing the sCAPA technique, we assemble multiple microcapsules into microswimmers with high precision, resulting in versatile microswimmers with multiple liquid compartments and programmable functionalities. Our work provides a flexible approach for the fabrication of modular microswimmers, which could potentially actively transport cargoes and release them on demand in the future.
Rail crack defect recognition based on a multi-feature fusion algorithm using electromagnetic acoustic emission technique
Authors: Chang Yongqi , Zhang Xin , Song Shuzhi , Song Qinghua , Shen Yi
Published: July 2023

Multi-feature fusion has been widely used to enhance recognition accuracy for different health stages of rails, which may lead to high dimensionality and information redundancy of signals. In addition, conventional supervised methods require plenty of labeled samples with class information, which can take significant time and involve high economic costs. In order to improve the effectiveness of the electromagnetic acoustic emission technique in rail crack defect recognition, a novel method including multi-feature fusion based on weakly supervised learning and recognition threshold construction is proposed in this paper. First, a mechanism consisting of multi-feature extraction and feature selection is developed to fully reflect the information of different health stages of the rail and avoid interference caused by the ineffective features. Then, the effective features and a novel weakly unsupervised label are input into the self-normalizing convolutional neural network and long short-term memory model to construct the rail health indicator (RHI). Finally, the recognition threshold is calculated based on the characteristics of the RHI to achieve crack recognition automatically. Furthermore, the experimental results under different working conditions demonstrate that the proposed method achieves a higher recognition performance than other existing methods in rail crack defect recognition.
Solvothermal synthesis of TiO2 nanospheres for non-volatile memory and synaptic learning applications
Authors: Nikam Ankita S , Kamble Girish U , Patil Amitkumar R , Patil Sharad B , Sheikh Arif D , Takaloo Ashkan V , Gaikwad Pawan K , Kamat Rajanish K , Kim Jin H , Dongale Tukaram D
Published: July 2023

In this study, we used the one-pot solvothermal method to synthesize the TiO2 nanospheres (NSs) and used them for non-volatile memory and neuromorphic computing applications. Several analytical tools were used to understand the structural, optical, morphological, and compositional characteristics of synthesized TiO2 NSs. The tetragonal crystal structure of anatase TiO2 was formed, according to the Rietveld refined x-ray diffraction results. The NS morphology was confirmed by field emission scanning electron microscopy and transmission electron microscopy images. X-ray photoelectron spectroscopy was probed to understand the elemental composition and electronic states of the TiO2 NSs. We specifically looked at the impact of reaction time on the structural, optical, morphological, compositional, and resistive switching (RS) properties of TiO2 NSs. The fabricated devices (Ag/TiO2 NSs/FTO) exhibit bipolar RS behavior. The optimized RS device shows good endurance (5000 cycles) and memory retention (5000 s) properties. Moreover, fabricated devices showed double-valued charge-flux characteristics, whereas charge transport was caused by the Ohmic and space charge-limited current mechanisms. Additionally, the optimized device can mimic various synaptic characteristics including potentiation-depression, excitatory post-synaptic current, and paired-pulse facilitation.
Exoplanets: an easy, practice-oriented and fun project with Arduino
Authors: Schnider Dorottya , Hömöstrei Mihály
Published: July 2023

Planets outside the solar system are not covered in most curricula, but the methods of exoplanet research have already appeared in high school physics education in connection with certain physics matura exam tasks. Exoplanet research is one of the most successful, modern, and evolving fields of today’s astronomy; thus, it is worth addressing in high schools. In the field of physics education, it is necessary to broaden the range of methodologies. The process of educational development and changing curricula requires the use of new ideas in addition to traditional methods. In this paper, we introduce a project-based lesson plan that follows the principles of competence-based physics teaching methodology, which guides high school students from the basics towards more complex and abstract knowledge. The aim of the project is to give students the opportunity to get involved in the classroom work and in their own learning processes, practice through interactive activities, acquire useful and practical knowledge, and develop skills, such as designing a measurement setup, digital data processing, evaluating measurement data and outcomes, and representing data graphically. The existence of these skills is essential for success in the field of engineering, technology and research. Student experimentation with the application of Arduino in the topic of exoplanets provides the opportunity for students to participate actively in the lessons, use digital devices, and develop skills and competences while participating in a fun project.
Isotope dependence of transport in ST40 hot ion mode plasmas
Authors: Kaye S M , Sertoli M , Buxton P , Dnestrovskii A , McNamara S , Romanelli M , Thomas P
Published: July 2023

The ST40 compact, high-field spherical tokamak, operating at 2.1 T and with 1.8 MW of neutral beam heating, achieved central carbon impurity ion temperatures in excess of 10 keV, surpassing their business milestone of 100 M ∘C (8.6 keV). The high temperature discharges were in the hot ion mode, with

T
i

≫

T
e

, and they were achieved in both hydrogen and deuterium plasmas with deuterium neutral beam injection. In order to achieve the high temperature scenarios, careful wall conditioning and scenario optimization was carried out in

H
0

→

H
+

,

D
0

→

H
+

, and finally in

D
0

→

D
+

plasmas. The TRANSP transport code was employed to study the dependence of confinement and transport on isotopic mass, and the conditions that led to the high measured central ion temperatures in the

D
0

→

H
+

and

D
0

→

D
+

plasmas. The kinetic profiles input into TRANSP were inferred from line-of-sight and limited radial measurements as well as consistency with a number of other experimental constraints. The TRANSP results first showed that the main species central ion temperature was only 0.5–1 keV lower than the measured carbon impurity temperature, and thus in the high performance plasmas also surpassed the 100 M ∘C level. TRANSP also showed that while the electron thermal conduction loss was dominant, reductions in central ion transport, and an effective decoupling of the ions from the electrons, led to an increase in central ion temperatures with increasing plasma mass. In fact, the associated confinement times exhibited a strong dependence on the isotopic mass of the thermal plasma. These preliminary results are foundations for dedicated experiments with full kinetic profile measurements on ST40 in the next run campaign.
A novel rapamycin cream formulation improves facial angiofibromas associated with tuberous sclerosis complex: a double-blind randomized placebo-controlled trial
Authors: Aitken Phillip , Stanescu Ioana , Boddington Laura , Mahon Caroline , Fogarasi Andras , Liao Yi-Hua , Ivars Marta , Moreno-Artero Ester , Trauner Doris , DeRoos Steven T , Jancic Jasna , Nikolic Milos , Balážová Patrícia , Price Harper N , Hadzsiev Kinga , Riney Kate , Stapleton Stacie , Tollefson Megha M , Bauer Derek , Pinková Blanka , Atkinson Hartley
Published: July 2023

Background

Facial angiofibromas (FAs) are a major feature of tuberous sclerosis complex (TSC). Topical rapamycin can successfully treat FAs. A new stabilized cream formulation that protects rapamycin from oxidation has been developed in 0.5% and 1% concentrations.

Objectives

To assess the efficacy and safety of a novel, stabilized topical rapamycin cream formulation.

Methods

This multicentre double-blind randomized placebo-controlled dose–response phase II/III study with a parallel design included participants aged 6–65 years with FAs of mild or moderate severity according to the Investigator’s Global Assessment (IGA) scale. Participants were randomized to one of three treatment arms: topical rapamycin 0.5%, topical rapamycin 1% or placebo. Treatment was applied once daily for 26 weeks. Safety and efficacy measures were assessed at days 14, 56, 98, 140 and 182. The primary endpoint was the percentage of participants achieving IGA scores of ‘clear’ or ‘almost clear’ after 26 weeks of treatment. Secondary measures included Facial Angiofibroma Severity Index (FASI) and participant- and clinician-reported percentage-based improvement. Safety measures included the incidence of treatment-emergent adverse events and blood rapamycin concentration changes over time.

Results

Participants (n = 107) were randomized to receive either rapamycin 1% (n = 33), rapamycin 0.5% (n = 36) or placebo (n = 38). All treated participants were included in the final analysis. The percentage of participants with a two-grade IGA improvement was greater in the rapamycin 0.5% treatment group (11%) and rapamycin 1% group (9%) than in the placebo group (5%). However, this was not statistically significant [rapamycin 0.5%: odds ratio (OR) 1.71, 95% confidence interval (CI) 0.36–8.18 (P = 0.50); rapamycin 1%: OR 1.68, 95% CI 0.33–8.40 (P = 0.53)]. There was a statistically significant difference in the proportion of participants treated with rapamycin cream that achieved at least a one-grade improvement in IGA [rapamycin 0.5%: 56% (OR 4.73, 95% CI 1.59–14.10; P = 0.005); rapamycin 1%: 61% (OR 5.14, 95% CI 1.70–15.57; P = 0.004); placebo: 24%]. Skin adverse reactions were more common in patients following rapamycin application (64%) vs. placebo (29%).

Conclusions

Both rapamycin cream formulations (0.5% and 1%) were well tolerated, and either strength could lead to clinical benefit in the treatment of FA.
Effects of social presence on behavioral, neural, and physiological aspects of empathy for pain
Authors: Petereit Pauline , Weiblen Ronja , Perry Anat , Krämer Ulrike M
Published: July 2023

In mediated interactions (e.g. video calls), less information is available about the other. To investigate how this affects our empathy for one another, we conducted an electroencephalogram study, in which 30 human participants observed 1 of 5 targets undergoing painful electric stimulation, once in a direct interaction and once in a live, video-mediated interaction. We found that observers were as accurate in judging others’ pain and showed as much affective empathy via video as in a direct encounter. While mu suppression, a common neural marker of empathy, was not sensitive to others’ pain, theta responses to others’ pain as well as skin conductance coupling between participants were reduced in the video-mediated condition. We conclude that physical proximity with its rich social cues is important for nuanced physiological resonance with the other’s experience. More studies are warranted to confirm these results and to understand their behavioral significance for remote social interactions.