bluuebunny/crossref_metadata_2025 huggingface dataset:
An innovative approach to control the Hf/Ti ratio in monolayers grown via atomic partial layer deposition
Authors: Pérez-Valverde M. I. , López-Luna E. , Martínez-Guerra E. , Hernández-Arteaga J. G. R. , Vidal M. A.
Published: September 2024

The Hf/Ti ratio was precisely controlled at monolayer thickness using atomic partial layer deposition (APLD). HfxTi1−xO2 films with varying Hf concentrations were deposited by adjusting the pulse time of Hf precursors within a single atomic layer. Characterization using x-ray reflectivity, x-ray photoelectron spectroscopy, and spectroscopic ellipsometry confirmed the presence of Hf, Ti, and O in the films. Increasing the Hf content caused the binding energies of the O 1s peak to shift to higher values, indicating a chemical environment change from TiO2-like to HfO2-like. A higher Hf content also increased the relative atomic percentages of Hf, Ti, and O, altering the film properties. The mass density and optical properties were notably sensitive to changes in the Hf/Ti ratio at monolayer thickness. The potential of APLD to reduce dimensionality through precise control of both thickness and composition renders it especially appropriate for applications requiring highly specific material properties.
Numerical prediction of passive speed and performance for multistage pump without power drive in natural flow process
Authors: Zhou Runze , Liu Houlin , Dong Liang , Ooi Kim Tiow , Kang Shaopeng , Cheng Zhiming
Published: September 2024

With the development of engineering applications and the increase in system complexity, some particular fields, such as liquid rocket engine turbopumps, aircraft engine fuel systems, and marine natural flow cooling systems, are increasingly focusing on the performance characteristics of pumps under natural flow conditions. The pump is in the form of resistance components under natural flow conditions without a power drive. The impeller undergoes passive rotation by the impact of inlet flow. Due to the specificity of its operating conditions and performance indicators, the pump's natural flow performance cannot be evaluated by regular methods. Therefore, this paper proposed a numerical prediction method for pump natural flow performance based on a coupled computational fluid dynamics coupled with six-degrees-of freedom model. The performance of a multistage pump with guide vanes was evaluated under different natural flow conditions, and the accuracy was verified by experimental measurements. The transient variation mode of pump performance parameters with time at the initial stage of natural flow impact was analyzed. The flow field's transient evolution characteristics and the wall shear stress variation during natural flow were investigated. It was found that the impeller's passive rotational speed increases linearly with the natural flow rate, while the hydraulic loss shows an exponentially increasing trend. Meanwhile, the natural flow loss coefficient shows an exponentially decreasing trend and gradually tends to a stable value. The high turbulent kinetic energy inside the impeller is mainly distributed in the flow separation region and large velocity gradients. The distribution of shear stresses is closely related to the flow behavior inside the pump and the geometrical features of the hydraulic components.
Swift heavy ion irradiation-induced enhancement of spin–orbit torque efficiency in Pt/Co/Ta trilayers
Authors: Zhang Jianrong , Li Yuzhi , He Xiaodong , Zhang Qi , Yan Ze , Chang Yuhan , Cui Baoshan , Zuo Yalu , Sheng Yan-bin , Xi Li
Published: September 2024

Increasing the efficiency of spin–orbit torque (SOT) is of great interest in applications for magnetic random access memory and logic devices due to decreased energy consumption. Here, we present that the SOT efficiency of Pt/Co/Ta films with perpendicular magnetic anisotropy can be improved by swift high-energy heavy Fe11+ ion irradiation, which is an effective method to alter crystallinity, interface roughness, and defects in ferromagnet/heavy metal heterostructures. Specifically, the Pt/Co/Ta films show an optimal SOT efficiency at ion fluence around 1.0 × 1013 ions/cm2 with the largest spin Hall angles reaching 0.59, which is the largest improvement of spin Hall angle by ion irradiation compared to previous studies using light ions. We demonstrate that the increase in SOT efficiency arises from structural changes in the Pt layer due to ion irradiation-induced damage effects at proper fluence, while the decrease in SOT efficiency is mainly attributed to the restoration of Pt crystallinity induced by beam-heating effects at high fluence. This work demonstrates that an appropriate ion irradiation process could improve the SOT efficiency and the spin Hall angle, thereby providing a way to develop future SOT-based spintronic devices.
Numerical investigation of wingtip aerodynamic interference of two flapping wings on opposite sides
Authors: Chen Zengshuang , Li Xiankai , Ma Ming , Zhang Yang , Meng Xueguang
Published: September 2024

Aerodynamic interference occurs at the wingtips when flying organisms fly in a V formation. In this paper, the wingtip aerodynamic interference of two flapping wings on opposite sides at low Reynolds numbers (Re) is numerically investigated. The effects of streamwise spacing (L1), spanwise spacing (L2), and phase angle (γ) on aerodynamic performance are considered. The results show that, compared to a single wing, a favorable combination of L1 and L2 can improve the overall thrust by 24% while keeping the overall lift essentially unchanged. In an unfavorable case, overall lift and thrust decrease by 18% and 20%, respectively. The overall aerodynamic forces are dominated by the rear wing. Analyzing the essential flow characteristics reveals the double-edged role of downwash and upwash in force generation. Moreover, it is found that the rear wing can realize the upwash/downwash exploitation by flap phasing, turning an unfavorable situation into a favorable one. The key flow physics behind this transformation lies in the relationship between the direction of wing motion and the direction of fluid velocity induced by vortices. These findings provide valuable insights into the understanding of biological phenomena and the design of new flapping wing vehicles.
Fuzzy uncertainty modeling of generalized Hirota–Satsuma coupled Korteweg–de Vries equation
Authors: Vana Rambabu , Karunakar Perumandla
Published: September 2024

This article explores the solitary wave solutions of a generalized Hirota–Satsuma Coupled Korteweg–de Vries (HSCKdV) equation. The HSCKdV equation is a mathematical model that describes certain types of long waves, particularly those found in shallow water. The generalized HSCKdV equation is solved exactly using the Homotopy Perturbation Transform Method (HPTM). By applying this technique, the authors obtain solutions in the form of a convergent power series. These solutions offer an understanding of the characteristics of solitary waves within the domain of shallow water waves. The HSCKdV equation has been solved using the adomian decomposition method, and the results have been compared with those obtained from the HPTM. This comparison demonstrates the effectiveness of the HPTM in solving such nonlinear equations. Further, the HSCKdV equation is extended to a fuzzy version considering the initial condition as a fuzzy parameter. Uncertainty in the initial condition is addressed by representing it using triangular and trapezoidal fuzzy numbers. The generalized fuzzy HSCKdV equation is subsequently tackled using the fuzzy HPTM (FHPTM) providing fuzzy bound solutions. Using the FHPTM, we explain the fuzzy results, highlighting how the solitary wave splits into two solitary waves and noting that the lower and upper bound solutions are interchanged due to negative fuzzy results.
Differences in microstructure and properties of Ti-based amorphous composites between recrystallization and partial remelting and semi-solid isothermal treatment
Authors: Huang Xin-hua , Chen Jin-heng , Wang Yu-huai , Luo Yong-xin , Ouyang Yue-jun
Published: September 2024

The as-cast specimens of Ti48Zr18V12Cu5Be17 amorphous composites were prepared by copper mold suction casting. Next, the as-cast specimens were treated using semi-solid isothermal treatment (SSIT) and recrystallization and partial remelting (RAP). The effects of SSIT and RAP on the microstructure and plasticity were analyzed. The results showed that the microstructure changed from fine crystals in the as-cast specimens to coarse bar crystals and near-spherical crystals in the SSIT and RAP specimens, respectively. The crystals of RAP specimens were finer and rounder than those of SSIT specimens due to recrystallization. In addition, the RAP specimens had high plasticity (20.93%), which is 428.5% and 45.2% higher than the as-cast and SSIT specimens, respectively. By observing the shear bands of the fractured specimens, it was found that the expansion of shear bands could not be impeded by the fine β-Ti crystals in the as-cast specimens, leading to an infinite extension that induces brittle fracture in the specimens. The essential cause of the poor plasticity of the as-cast specimens was revealed. In addition, the coarse β-Ti crystals effectively blocked the shear band expansion in the SSIT specimens, and a large number of shear bands were generated in these crystals. In contrast, the crystals of the RAP specimens had a greater number and density of shear bands compared to those of the SSIT specimens, and these shear bands intersected with each other in different directions. This revealed the mechanism by which the SSIT and RAP methods enhance the plasticity of amorphous composites.
A modified experimental approach for generating internal solitary waves using the dual paddle technique
Authors: Fan Wenhao , Zhi Changhong , You Yunxiang
Published: September 2024

A modification to the dual paddle wave generation method for internal solitary waves (ISWs) has been achieved through the implementation of the adjusted high-order unidirectional (aHOU) model and the Miyata–Choi–Camassa (MCC) model. This modified method utilizes layer-averaged horizontal velocities from ISWs in both the upper and lower fluid layers to control the operational velocities of the corresponding paddles. Experimental investigations conducted in a two-layer fluid with varied stratification conditions were employed to evaluate the applicability of the aHOU and MCC models. The validation of this approach involved examining the stability of generated ISWs by comparing experimental waveforms with theoretical predictions, demonstrating good agreement with prior research. Furthermore, evaluation of the modified wave generation method included an analysis of dimensionless phase velocity and characteristic frequency. The study also explored the quasi-linear relationship between the designed wave amplitude and the actual wave amplitude, establishing a polynomial fit between the actual wave amplitude and the layer thickness ratio. This approach offers a new method for stable and controllable laboratory generation of ISWs. Under finite water depth conditions, the method can produce ISWs that propagate stably over long distances and effectively control parameters such as wave amplitude and wave profile across a broad range of wave amplitudes and stratifications. These results confirm the effectiveness of the modified method and underscore its practical applicability in ISWs generation.
Interaction leads to symmetry breaking in an array of cantilever plates in oscillatory cross flow
Authors: Zhu Qiang
Published: September 2024

By using a computational model based on the immersed-boundary framework, a new mode of symmetry breaking is discovered in a fluid–structure interaction problem featuring an array of cantilever plates in a cross flow whose strength and direction varies sinusoidally with time. Specifically, within the physical parameters considered in this study, the motion of a single plate remains symmetric, whereas a system containing multiple plates can move asymmetrically so that the symmetry-breaking instability comes from fluid-dynamic interactions among individual plates. Further examination suggests that vortices shed from the free ends of the plates play an important role. Indeed, symmetry breaking occurs only when these vortices are sufficiently strong and when the distance between plates lies within certain range. If the distance is too small, a vortex shed from one plate can only stay in the gap between this plate and its neighboring plate for a short time so that it does not have the chance to interact extensively with the neighbor. On the other hand, if the distance is too large it is also difficult for this vortex to interact with the neighbor since it has to travel a long distance to reach there while the background flow keeps changing its direction. In either case, the system does not display asymmetric behavior.
Magnetic field-mediated ferrofluid droplet deformation in extensional flow
Authors: Bhattacharjee Debdeep , Atta Arnab , Chakraborty Suman
Published: September 2024

Extensional flow is vital in droplet dynamics, influencing their formation, size, stability, and functionality across diverse applications from industrial processes to biomedical technology. Ferrofluid droplets are pivotal in many such applications, where magnetic fields enable non-contact manipulation without undesirable heating effects. However, controlling ferrofluid droplet dynamics in magnetically influenced extensional flows is challenging due to the complex interplay of induced magnetization, intrinsic magnetic properties, and flow kinematics. Here, we present a first-principle-based theory delving into the morphology of a ferrofluid droplet under the combined influence of an external magnetic field and extensional flow. Unlike previous studies, we employ an asymptotic analysis that delves on the shape alterations by considering local magnetization as dependent on magnetic field intensity. Additionally, we develop a numerical model based on phase-field hydrodynamics to establish the practical applicability of the asymptotic solution and to explore large droplet-deformation regimes. The study demonstrates that increasing the magnetic field intensity, the saturation magnetization of the ferrofluid, and the initial magnetic susceptibility each independently improve droplet deformation. Additionally, we found that in a uniform magnetic field, the extensional viscosity of a ferrofluid emulsion is influenced by the strain rate, leading to strain-thickening behavior in the dilute emulsion. Our findings offer new insights into field-assisted manipulation of ferrofluid droplets, emphasizing their potential in applications ranging from process engineering to biomedical technology.
Passive flow control of a Francis turbine operating in sand-laden rivers for mitigating sediment erosion
Authors: Zhao Zilong , Guo Zhiwei , Qian Zhongdong
Published: September 2024

In a typical Francis turbine operating in sand-laden rivers, owing to its complicated geometry and variable operating conditions, vortex structures appear and cause severe erosion damage to turbine components. Here, we present a bioinspired method to mitigate severe sediment erosion on Francis turbines. The proposed method includes a passive flow control strategy using biomimetic convex domes for the inter-blade vortex, a major contributor to severe sediment erosion on the turbine runner. The effects of biomimetic convex domes on sediment erosion are investigated through numerical simulations and experiments. The results indicate that biomimetic convex domes significantly reduce the impact velocity and accretion rate of the particles, eventually reducing sediment erosion by at least 50 %. The mechanism underlying the effect of convex domes on sediment erosion is their inhibition of the development of the inter-blade vortex. The convex domes induce small-scale vortices from the blade boundary layer. When located in the nascent region of the inter-blade vortex, the small-scale vortex effectively inhibits its formation. Moreover, convex domes placed in severe erosion areas can accelerate the dissipation process of the inter-blade vortex.
Fermi level limitation in Na1/2Bi1/2TiO3–BaTiO3 piezoceramics by electrochemical reduction of Bi
Authors: Hu Pengcheng , Huang Binxiang , Bremecker Daniel , Koruza Jurij , Albe Karsten , Klein Andreas
Published: September 2024

The (electro)chemical stability of undoped and Zn-doped 0.94Na1/2Bi1/2TiO3–0.06BaTiO3 lead-free piezoceramics (NBT–6BT) was studied. For this purpose, the Fermi level at the interface between NBT–6BT and Sn-doped In2O3 (ITO) electrode is varied by gradually reducing the ITO film either by annealing in vacuum or by applying a voltage across a Pt/NBT–6BT/ITO. The chemical and electronic changes are monitored in situ by x-ray photoelectron spectroscopy. The experiments reveal the formation of metallic Bi when the Fermi level is reaching a value of 2.23 ± 0.10 eV above the valence band maximum, while no reduction of Ti is observed. The electrochemical reduction of Bi constitutes an upper limit of the Fermi level at ≈1 eV below the conduction band minimum. High electron concentrations in the conduction band and a contribution of free electrons to the electrical conductivity of NBT–6BT can, therefore, be excluded. The reduction occurs for an ITO work function of 4.2–4.3 eV. As typical electrode materials such as Ag, Cu, Ni, or Pt have higher work functions, an electrochemical instability of the electrode interfaces in ceramic capacitors is not expected. Under the given experimental conditions (350 °C, electric fields <40 V/mm), no degradation of resistance and no enrichment of Na at the interface are observed.
Linear instability of a resting state of the magnetohydrodynamic flows of polymeric fluid in a cylindrical channel (generalized Vinogradov–Pokrovski model)
Authors: Tkachev D. L. , Yegitov A. V. , Biberdorf E. A.
Published: September 2024

We study a linear stability of a resting state for flows of incompressible viscoelastic fluid in an infinite cylindrical channel under the influence of an external uniform magnetic field directed parallel to the cylinder axis (we use a generalized rheological Vinogradov–Pokrovski model as mathematical model) in a class of axisymmetric periodic along the axial variable flows. We establish that for some values of the parameters in the case of an absolute conductivity bm=0, the magnetic field can substantially lessen the real part of an exponent for perturbations of the radial velocity component, which is the main element of the instability development. For general case bm≠0, we justify the possibility of removing the instability based on the performed calculations.
Low-temperature formation of Ti2AlN during post-deposition annealing of reactive multilayer systems
Authors: Nnaji Moses O. , Tavakoli David A. , Hitchcock Dale A. , Vogel Eric M.
Published: September 2024

Mn+1AXn-phase Ti2AlN thin-films were synthesized using reactive sputtering-based methods involving the deposition of single-layer TiAlN, and Ti/AlN and TiN/TiAl multilayers of various modulation periods at ambient temperature and subsequent annealing at elevated temperatures. Ex situ and in situ x-ray diffraction measurements were used to characterize the Ti2AlN formation temperature and phase fraction. During annealing, Ti/AlN multilayers yielded Ti2AlN at a significantly lower in situ temperature of 650 °C compared to TiN/TiAl multilayers or single-layer TiAlN (750 °C). The results suggest a reactive multilayer mechanism whereby distinct Ti and AlN layers react readily to release exothermic energy resulting in lower phase transition temperatures compared to TiN and TiAl layers or mixed TiAlN. With a modulation period of 5 nm, however, Ti/AlN multilayers yielded Ti2AlN at a higher temperature of 750 °C, indicating a disruption of the reactive multilayer mechanism due to a higher fraction of low-enthalpy interfacial TiAlN within the film.
Thermal effects on damping determination of perpendicular MRAM devices by spin-torque ferromagnetic resonance
Authors: Richter H. J. , Mihajlović G. , Chopdekar R. V. , Jung W. , Gibbons J. , Melendez N. D. , Grobis M. K. , Santos T. S.
Published: September 2024

We report device-level damping measurements using spin-torque driven ferromagnetic resonance on perpendicular magnetic random-access memory cells. It is shown that thermal agitation enhances the apparent damping for cells smaller than about 55 nm. The effect is fundamental and does not reflect a true damping increase. In addition to the thermal effect, it is still found that device-level damping is higher than film-level damping and increases with decreasing cell size. This is attributed to edge damage caused by device patterning.
Performance optimization for magnetoelectric antennas based on a multi-field coupling analysis model
Authors: Mao Yue , Jiao Qiyuan , Shi Yang
Published: September 2024

This paper presents a multi-field coupling model for magnetoelectric (ME) antennas, encompassing a ME film, electrode layers, and a substrate featuring a cavity structure. This model accounts for the nonlinear magnetoelastic coupling within the radiation layer and employs a combined DC and AC simulation methodology to capture the antenna's radiation mechanism. Leveraging this multi-field coupling model, performance differences between the ME antenna and an ideal ME composite film are analyzed. By exploring optimization schemes based on multi-physics fields, electrode materials, and structural design, the ME antenna's radiation performance is significantly enhanced. The findings demonstrate that the complete antenna structure, with its increased thickness and cavity design, exhibits a lower resonance frequency and a higher converse ME (CME) coefficient compared to the ideal ME film. The optimal CME effect is achieved under proper external stimuli, leading to a broader 3 dB bandwidth. Expanding the cavity dimensions enhances the CME coefficient by 42% and reduces the resonance frequency due to decreased acoustic wave loss. Adopting electrode materials with higher acoustic impedance elevates the CME coefficient, yet narrows the bandwidth. Conversely, using silver (Ag) electrodes promotes a broader bandwidth. Additionally, ME antenna arrays are designed to broaden the bandwidth by 300%.
Utility of a digital app to enhance patient–nurse communications and patient involvement in bedside handover: patient and nurse perceptions
Authors: Casey Penelope , Yuen Eva , Liskaser Raj , Blencowe Philippa , Boyd Leanne , Abdelrazek Mohamed , Wang Zoe , Considine Julie
Published: September 2024

Objective This study aimed to explore patient and nurse perceptions of using a prototype co-designed app to support patient–nurse communication and patient engagement in bedside handover. Methods This qualitative descriptive study evaluated usability of the app with a convenience sample of patient–nurse dyads in a 22-bed medical/oncology ward, during morning shifts. Participants were nurses, and patients proficient in English but without cognitive impairment or physical or mental distress. Patients entered healthcare questions and preferences into the app, nurses acknowledged the information in the app and responded during their usual workflow. Patient comfort level with app use was surveyed. Handovers were observed, and patient involvement rated. After handover, semi-structured interviews and feedback surveys on app usability were conducted. Interviews were recorded, transcribed, and then analysed thematically. Survey data were analysed using descriptive statistics. Results Patient–nurse dyads (n = 18) used the app between March and May 2023. Patients were mostly older (median 69.5 years; IQR 52.3, 75), female, and frequent users of smartphones. Nurses were mostly younger (median 23 years; IQR 21, 40) and female. Five themes were identified, which indicated that using the app empowered patients to engage in healthcare communications, facilitated opportunities for patient-centred information sharing, and refocused nurses’ attention onto patient-centred care. Views differed on the app’s influence on patient involvement in handover. Surveys (n = 36, 100%) indicated that the interface was easy to navigate, features were useful, and only minor amendments were suggested. Conclusion This prototype app shows potential to facilitate patient-centred communication and patient engagement with health care, including bedside handover. With further refinement and testing, this app could enhance experiences of care and reduce harm from miscommunication.
Glial
swip-10
controls systemic mitochondrial function, oxidative stress, and neuronal viability via copper ion homeostasis
Authors: Rodriguez Peter , Kalia Vrinda , Fenollar-Ferrer Cristina , Gibson Chelsea L. , Gichi Zayna , Rajoo Andre , Matier Carson D. , Pezacki Aidan T. , Xiao Tong , Carvelli Lucia , Chang Christopher J. , Miller Gary W. , Khamoui Andy V. , Boerner Jana , Blakely Randy D.
Published: September 2024

Cuprous copper [Cu(I)] is an essential cofactor for enzymes that support many fundamental cellular functions including mitochondrial respiration and suppression of oxidative stress. Neurons are particularly reliant on mitochondrial production of ATP, with many neurodegenerative diseases, including Parkinson’s disease, associated with diminished mitochondrial function. The gene
MBLAC1
encodes a ribonuclease that targets pre-mRNA of replication-dependent histones, proteins recently found in yeast to reduce Cu(II) to Cu(I), and when mutated disrupt ATP production, elevates oxidative stress, and severely impacts cell growth. Whether this process supports neuronal and/or systemic physiology in higher eukaryotes is unknown. Previously, we identified
swip-10
, the putative
Caenorhabditis elegans
ortholog of
MBLAC1
, establishing a role for glial
swip-10
in limiting dopamine (DA) neuron excitability and sustaining DA neuron viability. Here, we provide evidence from computational modeling that SWIP-10 protein structure mirrors that of MBLAC1 and locates a loss of function coding mutation at a site expected to disrupt histone RNA hydrolysis. Moreover, we find through genetic, biochemical, and pharmacological studies that deletion of
swip-10
in worms negatively impacts systemic Cu(I) levels, leading to deficits in mitochondrial respiration and ATP production, increased oxidative stress, and neurodegeneration. These phenotypes can be offset in
swip-10
mutants by the Cu(I) enhancing molecule elesclomol and through glial expression of wildtype
swip-10
. Together, these studies reveal a glial-expressed pathway that supports systemic mitochondrial function and neuronal health via regulation of Cu(I) homeostasis, a mechanism that may lend itself to therapeutic strategies to treat devastating neurodegenerative diseases.
Inequality aversion predicts support for public and private redistribution
Authors: Epper Thomas F. , Fehr Ernst , Kreiner Claus Thustrup , Leth-Petersen Søren , Olufsen Isabel Skak , Skov Peer Ebbesen
Published: September 2024

Rising inequality has brought redistribution back on the political agenda. In theory, inequality aversion drives people’s support for redistribution. People can dislike both advantageous inequality (comparison relative to those worse off) and disadvantageous inequality (comparison relative to those better off). Existing experimental evidence reveals substantial variation across people in these preferences. However, evidence is scarce on the broader role of these two distinct forms of inequality aversion for redistribution in society. We provide evidence by exploiting a unique combination of data. We use an incentivized experiment to measure inequality aversion in a large population sample (≈9,000 among 20- to 64-y-old Danes). We link the elicited inequality aversion to survey information on individuals’ support for public redistribution (policies that reduce income differences) and administrative records revealing their private redistribution (real-life donations to charity). In addition, the link to administrative data enables us to include a large battery of controls in the empirical analysis. Theory predicts that support for public redistribution increases with both types of inequality aversion, while private redistribution should increase with advantageous inequality aversion, but decrease with disadvantageous inequality aversion. A strong dislike for disadvantageous inequality makes people willing to sacrifice own income to reduce the income of people who are better off, thereby reducing the distance to people with more income than themselves. Public redistribution schemes achieve this but private donations to charity do not. Our empirical results provide strong support for these predictions and with quantitatively large effects compared to other predictors.
Conformational ensembles in
Klebsiella pneumoniae
FimH impact uropathogenesis
Authors: Lopatto Edward D. B. , Pinkner Jerome S. , Sanick Denise A. , Potter Robert F. , Liu Lily X. , Bazán Villicaña Jesús , Tamadonfar Kevin O. , Ye Yijun , Zimmerman Maxwell I. , Gualberto Nathaniel C. , Dodson Karen W. , Janetka James W. , Hunstad David A. , Hultgren Scott J.
Published: September 2024

Klebsiella pneumoniae
is an important pathogen causing difficult-to-treat urinary tract infections (UTIs). Over 1.5 million women per year suffer from recurrent UTI, reducing quality of life and causing substantial morbidity and mortality, especially in the hospital setting. Uropathogenic
E. coli
(UPEC) is the most prevalent cause of UTI. Like UPEC,
K. pneumoniae
relies on type 1 pili, tipped with the mannose-binding adhesin FimH, to cause cystitis. However,
K. pneumoniae
FimH is a poor binder of mannose, despite a mannose-binding pocket identical to UPEC FimH. FimH is composed of two domains that are in an equilibrium between tense (low-affinity) and relaxed (high-affinity) conformations. Substantial interdomain interactions in the tense conformation yield a low-affinity, deformed mannose-binding pocket, while domain–domain interactions are broken in the relaxed state, resulting in a high-affinity binding pocket. Using crystallography, we identified the structural basis by which domain–domain interactions direct the conformational equilibrium of
K. pneumoniae
FimH, which is strongly shifted toward the low-affinity tense state. Removal of the pilin domain restores mannose binding to the lectin domain, thus showing that poor mannose binding by
K. pneumoniae
FimH is not an inherent feature of the mannose-binding pocket. Phylogenetic analyses of
K. pneumoniae
genomes found that FimH sequences are highly conserved. However, we surveyed a collection of
K. pneumoniae
isolates from patients with long-term indwelling catheters and identified isolates that possessed relaxed higher-binding FimH variants, which increased
K. pneumoniae
fitness in bladder infection models, suggesting that long-term residence within the urinary tract may select for higher-binding FimH variants.
Manipulation of natural transformation by AbaR-type islands promotes fixation of antibiotic resistance in
Acinetobacter baumannii
Authors: Tuffet Rémi , Carvalho Gabriel , Godeux Anne-Sophie , Mazzamurro Fanny , Rocha Eduardo P. C. , Laaberki Maria-Halima , Venner Samuel , Charpentier Xavier
Published: September 2024

The opportunistic pathogen
Acinetobacter baumannii
, carries variants of
A. baumannii
resistance islands (AbaR)-type genomic islands conferring multidrug resistance. Their pervasiveness in the species has remained enigmatic. The dissemination of AbaRs is intricately linked to their horizontal transfer via natural transformation, a process through which bacteria can import and recombine exogenous DNA, effecting allelic recombination, genetic acquisition, and deletion. In experimental populations of the closely related pathogenic
Acinetobacter nosocomialis
, we quantified the rates at which these natural transformation events occur between individuals. When integrated into a model of population dynamics, they lead to the swift removal of AbaRs from the population, contrasting with the high prevalence of AbaRs in genomes. Yet, genomic analyses show that nearly all AbaRs specifically disrupt
comM
, a gene encoding a helicase critical for natural transformation. We found that such disruption impedes gene acquisition, and deletion, while moderately impacting acquisition of single nucleotide polymorphism. A mathematical evolutionary model demonstrates that AbaRs inserted into
comM
gain a selective advantage over AbaRs inserted in sites that do not inhibit or completely inhibit transformation, in line with the genomic observations. The persistence of AbaRs can be ascribed to their integration into a specific gene, diminishing the likelihood of their removal from the bacterial genome. This integration preserves the acquisition and elimination of alleles, enabling the host bacterium—and thus its AbaR—to adapt to unpredictable environments and persist over the long term. This work underscores how manipulation of natural transformation by mobile genetic elements can drive the prevalence of multidrug resistance.
Synaptotagmin-1 in phase: Condensate biology reveals new insights into the synaptic calcium sensor
Authors: Tromm Johannes Vincent , Milovanovic Dragomir
Published: September 2024

Two recent papers by Mehta et al. and Zhu et al. in this issue (https://doi.org/10.1083/jcb.202311191) discover that synaptotagmin-1, the primary calcium sensor at the synapse, forms biomolecular condensates, identifying a new layer of regulation in calcium-triggered synaptic vesicle exocytosis.
Using neural networks for image analysis in general physiology
Authors: Rios Eduardo
Published: September 2024

An article with three goals, namely, to (1) provide the set of ideas and information needed to understand, at a basic level, the application of convolutional neural networks (CNNs) to analyze images in biology; (2) trace a path to adopting and adapting, at code level, the applications of machine learning (ML) that are freely available and potentially applicable in biology research; (3) by using as examples the networks described in the recent article by Ríos et al. (2024. https://doi.org/10.1085/jgp.202413595), add logic and clarity to their description.
Quantum and classical properties of the Universe according to unimodular quantum cosmology
Authors: Riahi Natascha
Published: September 2024

We investigate the dynamical behavior of wavepacket solutions due to unimodular quantum cosmology. We find early and late time quantum eras of the Universe. An Ehrenfest theorem ensures quasi-classical behavior for the late time Universe if the quantum uncertainties are small. The surprising prediction of late time quantum effects for a flat, homogeneous and isotropic Universe with a scalar field with an exponential potential is obtained by the analysis of the uncertainty dynamics using the results of the corresponding classical dynamical system. Furthermore quantum correction terms to the Hubble parameter and the matter density are derived. A positive matter expectation value for the de-Sitter Universe raises the question if correction terms due to quantum gravity could contribute to solve the dark matter problem.
Toroidal mode trapping in a magnetic meta-molecule
Authors: Wu Tong , Evlyukhin Andrey B , Tuz Vladimir R
Published: September 2024

In this paper, we establish the relationship between the eigenmodes and the scattering characteristics of a meta-molecule made of magnetic disks from the point of view of the manifestation of its toroidal response. In particular, we examine the electric and magnetic dipole contributions to the scattering cross-sections obtained in the framework of the multipole decomposition method while accounting for the polarizability and magnetization induced in the structure by the field of incoming radiation. We find out that with increasing permeability, the toroidal mode is trapped in the meta-molecule due to the presence of its magnetization part, which may have a practical perspective in gyrotropy, permittivity, and permeability sensing.
A collaborative fault diagnosis model based on an attention-weighted multiscale convolutional neural network and an improved multi-grained cascade forest
Authors: Liu Xiuyan , Wang Xiaofeng , Pang Chunqiu , Deng Zhaopeng , Guo Tingting
Published: September 2024

The health of rolling bearings is of great significance to ensure the smooth operation of rotating machinery. Failure of rolling bearings will lead to severe accidents, prolonged downtime or substantial economic losses. Therefore, timely monitoring and diagnosing the health status of rolling bearings is essential to ensure the reliable operation of industrial systems. Deep learning methods have widely applied in industry due to their powerful feature extraction capabilities. However, the fault signals of rolling bearings with complex and variable working conditions exhibit high nonlinearity. To extract the nonlinear features of the fault signal, the traditional deep models often have complex structures and large parameter matrices. It is challenging to train models, obtain high efficiency, and achieve satisfactory results. Therefore, a novel collaborative diagnostic model (MsCNN-IgcForest) based on an attention-weighted multiscale convolutional neural network (MsCNN) and an improved multi-grained cascade forest (IgcForest) is proposed to process bearing fault signals. First, inspired by Xception, we design a lightweight attention-weighted MsCNN feature extraction model that uses attention mechanisms to suppress scattered features and improve the running speed by reducing the number of network training parameters. Second, the improved deep forest employs an attention-weighted MsCNN structure as a classifier instead of multi-grained scanning to reduce memory consumption and achieve fault recognition. Finally, the MsCNN-IgcForest model is verified by two cases of bearing diagnosis and the contrastive results show high fault diagnosis accuracy and strong robustness. In conclusion, the improved model shows good fault diagnosis performance and has a potential reference value for industrial fault diagnosis.
Long-term tracking for high-frequency surface wave radar based on heading constraint filtering combined ELM
Authors: Wang Jiaqi , Liu Aijun , Yu Changjun
Published: September 2024

Aiming at the problem of low measurement resolution and poor tracking accuracy in high-frequency surface wave radar (HFSWR) tracking field, a tracking method that combines the heading constraint filter and extreme learning machine (ELM) is proposed. Compared with the existing research, the innovation of this study lies in proposing a two-stage tracking method based on the short-term stable state of the target, and similarity of long-term trajectory. Firstly, the heading constraint information is introduced into the estimator and improve the estimation accuracy. In multi-target tracking scenarios, many tracklets can be obtained. Then, the ELM learns robust features of tracklets to achieve the trajectory segment classification from the same target. This method can be widely applied to long-term tracking of cargo or passenger ships with fixed destinations, significantly improving tracking performance by utilizing implicit domain knowledge without additional information. The actual data of this paper comes from HFSWR on Bohai Bay. Both the simulation and actual measurement experiments show that the proposed cascaded tracking method achieves long-term continuous tracking, and generates more complete trajectories. Moreover, the proposed Extended Kalman filter based on pseudo-measurement and intercept parameters exhibits better tracking stability and accuracy in limited scan steps. This study provides new ideas and methods for improving the tracking performance of special targets in the HFSWR field by utilizing motion features.
A hybrid mesoscale-continuum approach to understand and predict melting kinetics of Al powders during laser processing
Authors: Chen Ching , Galitskiy Sergey , Ivanov D S , Dongare Avinash M
Published: September 2024

Laser interaction with metallic powders during additive manufacturing (AM) leads to fast heating and cooling rates that can affect the quality of the final products due to the formation of defects. One of the first steps towards predicting microstructures generated during AM, therefore, requires an accurate understanding of the laser energy deposition mechanisms that determine the melting kinetics at the level of individual powders. The critical challenge, however, is the availability of computational methods that can model the laser energy absorption, heat transfer, and the related microstructure evolution in individual metal powders at the length and time scales of AM. This manuscript demonstrates the capability of a novel scale-bridging methodology that combines the mesoscale quasi-coarse-grained dynamics (QCGD) simulations with a continuum two-temperature model (TTM) to account for the atomistic mechanisms of laser energy deposition and microstructure evolution and predict the kinetics of melting of individual powders at the experimental time and length scales. The scale-bridging capability of the hybrid QCGD-TTM simulations is demonstrated here by investigating the laser-induced microstructure evolution in aluminum powders with various sizes ranging from 200 nm to 20 µm. The analysis of the evolution of temperature, pressure, phase fraction, and melt fronts suggests the melting mechanism is heterogeneous due to the interaction with a laser, and the melting time is observed to decrease exponentially as the laser intensity increases. The solid–liquid interface velocity can be quantified to identify correlations with interface temperatures, and the predicted values satisfy the theoretically reported limits of crystal stability of metals against homogeneous melting. In addition, the pre-melting is found at the grain boundaries of 20 µm polycrystalline aluminum powder, while a minute contribution to melting is observed. This manuscript demonstrates the capability of the QCGD-TTM method to capture laser-powder interaction and allow the investigation of the kinetics of laser melting.
Cellular automaton simulation of solid-phase grain growth under conditions involving scanning heat sources and temperature gradients
Authors: Murata Kenji , Chen Ta-Te , Sun Fei , Adachi Yoshitaka
Published: September 2024

A cellular automaton simulation of grain growth in a solid phase was conducted, considering the temperature gradient, heat source movement, and conditions favoring prioritized grain growth. The results reveal that, under optimal conditions, cellular grains elongated in the direction of the heat source movement. Detailed simulations illustrate the dynamics of grain growth and effect of mobility and driving forces on the dynamics, providing valuable insights into cellular grain growth in a solid phase.
Genetic algorithm optimization of langevin thermostat and thermal properties of graphene-aluminum nanocomposites: a molecular dynamics
Authors: Toprak Kasim
Published: September 2024

The thermal properties of a laminated structure of graphene-coated aluminum composite nanomaterial were investigated through non-equilibrium molecular dynamics (NEMD) simulations to address the problem of temperature deviation in the thermostat volume applied. This paper presents a new insight into the best values of timestep and Langevin thermostat damping parameters for each atom in the nanomaterial with different size configurations using the genetic algorithm (GA) method by considering the timestep and thermostat damping parameters for each atom type, as well as the thickness of the nanomaterial, the thermostat, buffer, and heat flow lengths. The initial population results indicate that the thermostat temperature deviation increases with higher thermostat damping coefficients and timestep. However, the deviation decreases significantly with increased heat flow and thermostat lengths. Variations in buffer length and aluminum thickness do not have a significant effect on temperature. The application of a GA for optimization leads to a decrease in thermostat temperature deviation. The optimized parameters resulted in better thermostat temperature deviations when analyzing the temperature, aluminum thickness, and both buffer and thermostat lengths. Additionally, the thermal conductivity of aluminum-graphene nanomaterial decreases with increasing temperature, buffer length, and aluminum thickness, but increases by up to 9.85% with increasing thermostat length.
4D printing of polylactic acid (PLA)/PLA-thermoplastic polyurethane (TPU)-based metastructure: examining the mechanical, thermal, and shape memory properties
Authors: Ladakhan Saiyadali H , Sreesha Rakshith B , Makireddypalli Adinarayanappa Somashekara
Published: September 2024

In the present day and age, increasing demand concerning the enhancement of the mechanical performance of shape memory polymer (SMP) based structures has paved the way for developing newer metastructures of enhanced load-bearing, damping capacity, and durability. The present study focuses on developing SMP-based metastructures made of commercially available polylactic acid (PLA) and 30% by wt. of thermoplastic polyurethane (TPU) blended PLA. The designed metastructures are initially analyzed using numerical modeling to prevent lateral deformation, acute stress concentration zones, and row-wise collapse. Mechanical tests reveal that blending TPU with PLA enhances the material’s flexibility and ductility, further improving the toughness and fracture resistance of the built metastructures. Loading-unloading and shape recovery tests (under compression mode) of the s-shape metastructure reveal that the PLA/TPU metastructure withstands ≅ 170 N load, less than neat PLA’s ≅ 223 N due to TPU’s flexibility. PLA/TPU endures 30 cycles, while PLA fails after the 9th cycle. In shape recovery plots, PLA/TPU metastructures exhibit a lower standard deviation (∼0.32%) than PLA (∼1.4%), attributed to the entropy decrease and cross-linkage disentanglements of PLA. Furthermore, a dynamic mechanical analyzer (DMA) assesses glass transition temperature, energy storage capability, and dissipation in variation with the temperature. The nephograms of ABAQUS result divulge accurate fracture initiation locations of the metastructure unit cells, which involves implementing ductile damage behavior modeling by employing damage initiation and evolution parameters. Finally, assessing compression tests and shape recovery behavior results elucidates that these SMP-based metastructures are promising for load-bearing pallets in the transporting and packaging industries, providing superior damping and self-repairing capabilities during significant plastic deformations.
A multi attribute decision making framework based on partitioned dual Maclaurin symmetric mean operators under Fermatean fuzzy environment
Authors: Roy Susmita
Published: September 2024

In information aggregation, the Maclaurin symmetric mean (MSM) operator has drawn a lot of interest to the researchers. And, partitioned dual MSM (PDMSM) has a precondition that all attributes are grouped into several partitions and the attributes in the same partition are relevant to other attributes in the same group, while the attributes located in different groups have no relation. The Fermatean fuzzy set (FFS), on the other hand, is a potent mathematical model that effectively manages uncertain data. The existing FFS-based multi attribute decision making (MADM) techniques fail to evaluate the partitions of the relative attributes, the interdependencies between various criteria, and the ability to mitigate the detrimental impacts of irrelevant criteria. Motivated by these issues, this paper proposes novel operators named FFPDMSM and weighted FFPDMSM to handle the scenarios where criteria are divided into distinct parts and there are interconnections among multiple criteria within the same part. The proposed operators deal not only with interrelationships between criteria but also with partitioned relationships among criteria. Some properties of the proposed operators are discussed in detail. Further, an MADM approach is developed based on the proposed operators in the FF environment. A realistic numerical illustration with sensitivity analysis is demonstrated to validate the proposed approach. Finally, the method is compared with different existing techniques to demonstrate the proposed method’s applicability and feasibility.