bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular basis for receptor recognition and broad host tropism for merbecovirus MjHKU4r-CoV-1
Authors: Zhao Zhennan , Li Xin , Chai Yan , Liu Zhifeng , Wang Qihui , Gao George F
Published: June 2024

A novel pangolin-origin MERS-like coronavirus (CoV), MjHKU4r-CoV-1, was recently identified. It is closely related to bat HKU4-CoV, and is infectious in human organs and transgenic mice. MjHKU4r-CoV-1 uses the dipeptidyl peptidase 4 (DPP4 or CD26) receptor for virus entry and has a broad host tropism. However, the molecular mechanism of its receptor binding and determinants of host range are not yet clear. Herein, we determine the structure of the MjHKU4r-CoV-1 spike (S) protein receptor-binding domain (RBD) complexed with human CD26 (hCD26) to reveal the basis for its receptor binding. Measuring binding capacity toward multiple animal receptors for MjHKU4r-CoV-1, mutagenesis analyses, and homology modeling highlight that residue sites 291, 292, 294, 295, 336, and 344 of CD26 are the crucial host range determinants for MjHKU4r-CoV-1. These results broaden our understanding of this potentially high-risk virus and will help us prepare for possible outbreaks in the future.
In vivo biodistribution and tumor uptake of [64Cu]-FAU nanozeolite via positron emission tomography Imaging
Authors: Hélaine Charly , Amedlous Abdallah , Toutain Jérôme , Brunaud Carole , Lebedev Oleg , Marie Charlotte , Alliot Cyrille , Bernaudin Myriam , Haddad Ferid , Mintova Svetlana , Valable Samuel
Published: June 2024

Nanoparticles have emerged as promising theranostic tools for biomedical applications, notably in the treatment of cancers.
A LIBSVM quality assessment model for apple spoilage during storage based on hyperspectral data
Authors: Wang Zhihao , Yin Yong , Yu Huichun , Yuan Yunxia
Published: June 2024

To assess the quality of apple samples during storage, a quality assessment model was developed utilizing LIB Support Vector Machine (LIBSVM).
Vapochromic separation of toluene and pyridine azeotropes using adaptive macrocycle co-crystals
Authors: Li Bin , Wang Yun , Wang Yuan , Liu Yue , Wang Lu , Zhang Zhi-Yuan , Li Chunju
Published: June 2024

The separation of toluene (Tol) and pyridine (Py) azeotropes is significant in the chemical industry.
Cationic ligands – from monodentate to pincer systems
Authors: Zafar Mohammad , Subramaniyan Vasudevan , Tibika Françoise , Tulchinsky Yuri
Published: June 2024

Incorporation of cationic ligands within pincer frameworks allowed to develop them from obscure peculiarities into a diverse class of ancillary ligands.
Catalyst-free contact-electro-catalytic H2O2 synthesis via simple combination of a poly(tetrafluoroethylene) stir bar and ultrasound
Authors: Wang Yao , Wang Yanfeng , Hu Baowei , Qiu Muqing , Gao Guandao , Wei Peiyun
Published: June 2024

A catalyst-free contact-electro-catalytic method for H2O2 production was developed by combining continuous agitation with a poly(tetrafluoroethylene) stir bar and ultrasonication.
Efficient carbene transfer reactivity mediated by Fe(ii) complexes supported by bulky alkoxides
Authors: Kulathungage Lakshani W. , Kurup Sudheer S. , Browne Edison A. , Spalink Gabriel H. , Ward Cassandra L. , Lord Richard L. , Groysman Stanislav
Published: June 2024

The reaction of Fe(OR)2(THF)2 (OR = bulky alkoxide ligand) with PhIC(CO2Me)2 results in the formation of reactive remote carbene/vinyl radical intermediate that undergoes facile cyclopropanation or dimerization.
Systematic Raman spectroscopic study of the complexation of uranyl with fluoride
Authors: Yang Yating , Liu Qian , Lan Youshi , Zhang Qianci , Zhu Liyang , Yang Suliang , Tian Guoxin , Cao Xiaoyan , Dolg Michael
Published: June 2024

A combined Raman spectroscopic and quantum chemical investigation provides thermodynamic and structural information of UO2F+, UO2F2(aq), UO2F3−, UO2F42−, and UO2F53− in aqueous solution.
Edible bird's nest regulates glucose and lipid metabolic disorders via the gut–liver axis in obese mice
Authors: Zhang Wei , Zhu Meizhen , Liu Xuncai , Que Maoyao , Dekyi Kelsang , Zheng Linxi , Zhang Yichen , Lv Youping , Fan Qunyan , Wang Xinyue , Li Hongwei
Published: June 2024

Edible bird's nest improves the imbalance of glycolipid homeostasis in obese mice by enhancing the gut microbiota and intestinal immunity, and promoting bile acid metabolism, and decreasing lipid absorption and synthesis via the gut–liver axis.
N,S-codoped carbon microporous structures derived from dead ginkgo leaves as efficient oxygen reduction reaction catalysts for Al–air batteries
Authors: Liu Kun , Zhang Angli , Liu Xiaowu , Liang Ting , Li Xin , Hu Ke , Ji Fanqing , Li Haoyi , Chen Xin , Fu Xucheng
Published: June 2024

The exploration and development of efficient and cost-effective oxygen reduction reaction (ORR) catalysts for non-metallic biomass have emerged as a crucial avenue for synthesizing diverse carbon nanomaterials.
Design, synthesis and antitumor study of novel NO-type porphyrin–ferulic acid derivatives for chemotherapy and photodynamic therapy
Authors: Liu Zhenhua , Yang Lingyan , Tian Zejie , Li Hui , Shi Lei , Tang Chen , Guo Yu , He Jun , Liu Yunmei
Published: June 2024

NO-type porphyrin-ferulic acid derivatives were obtained by combining NO donor, ferulic acid, and porphyrin. It can realize the combined treatment of phototherapy and chemotherapy and effectively kill cancer cells.
Anomalous intense emission of the 5D0/7F4 transition for reddish-orange light-emitting and fluorescent probe for multiple lattice sites in β-PbF2:Eu3+/K+ oxyfluoride glass ceramics
Authors: Xu Kejie , Zhao Lijuan , Guo Yuao , Fu Yuting
Published: June 2024

K+ ions as charge compensating ions doped into the fluorite lattice, vigorously regulating the lattice symmetry around rare earth ions, achieving luminescence efficiency enhancement and spectral broadening of rare earth ions.
Calix[4]arene with a stiff upper rim bridge: spontaneous macrocyclization, structure, and dynamic behaviour
Authors: Azov Vladimir A. , Warneke Jonas , Warneke Ziyan , Zeller Matthias , Twigge Linette
Published: June 2024

Macrocyclization of the upper rim disubstituted calix[4]arene is facilitated by the proximity of the reaction centers, imposed by the calixarene scaffold, affording the calix[4]arene with a short upper rim bridge and distorted backbone.
A topological nodal line semi-metal with a negative Poisson's ratio in a three-dimensional carbon network with sp2 hybridization
Authors: Jiang Wen , Jiang Jun , Zhang Zhixun , Wu Wenjie , Zhang Li-Chuan , Xie Yuee , Chen Yuanping
Published: June 2024

WZGN, a new 3D sp2 carbon network with a nodal ring and a negative Poisson's ratio (NPR).
A natural food-grade supramolecular self-assembly system for creation of hierarchically structured hydrogels
Authors: Yu Xinke , Cai Jiyang , Xu Mengyue , Li Qing , Yang Yunyi , Wan Zhili , Yang Xiaoquan
Published: June 2024

We develop a hierarchically structured hydrogel by supramolecular self-assembly of all-natural building blocks, glycyrrhizic acid and carrageenan, which can serve as responsive active cargo delivery platforms for food and biomedical applications.
Kinetic Monte Carlo simulations on electroforming in nanomanipulated conductive bridge random access memory devices
Authors: Li Yu-Chen , Xu Ping , Lv Yang-Yang , Fa Wei , Chen Shuang
Published: June 2024

Kinetic Monte Carlo simulations prove that the nano-manipulated dielectric layer plus the nanopore-containing ion-blocking layer leads to the formation of size-controlled and uniform filaments in conductive bridge random access memories.
Detecting Hearing Loss Through Targeted Surveillance: Risk Registry and Surveillance Timeframe Recommendations
Authors: Fitzgibbons E. Jane , Driscoll Carlie , Traves Lia , Beswick Rachael
Published: June 2024

Purpose:

The purpose of this study was to inform the revision of a targeted surveillance risk registry by identifying which risk factors predict postnatally identified hearing loss (PNIHL) in children who pass newborn hearing screening and to determine whether hearing surveillance beyond the age of 1 year is warranted.

Method:

We used retrospective analysis of the audiological outcomes of children born in the state of Queensland, Australia, between January 1, 2010, and December 31, 2019, who passed the newborn hearing screen with risk factors.

Results:

Approximately one third of children were lost to follow-up and could not be included in the analysis. Risk factors that predicted PNIHL in the analyzed cohort were as follows: syndromes associated with hearing loss, craniofacial anomalies, perinatal infections, and family history of permanent childhood hearing loss. Severe asphyxia did not predict PNIHL but yielded some cases of significant bilateral hearing loss. Hearing loss in children with a history of prolonged ventilation was mild and/or unilateral in nature (except in cases where the hearing loss was due to an unrelated etiology). There were no cases of PNIHL in children with hyperbilirubinemia or neonatal bacterial meningitis. For the risk factors that predicted PNIHL, nearly all hearing losses were detected by 1 year of age, except for children with family history where one quarter of hearing losses had a later onset.

Conclusions:

The four risk factors recommended for efficient postnatal identification of hearing loss are as follows: syndromes associated with hearing loss, craniofacial anomalies, perinatal infection, and family history of permanent childhood hearing loss. Hearing surveillance through to 1 year old is sufficient except for children with a family history, where a second phase assessment is indicated. Alternative targeted surveillance protocols and models of care are required to minimize loss to follow-up.
Influence of Coulomb scattering on the proton radiography of electric and magnetic fields in plasmas
Authors: Deng Luan , Du Bao , Cai Hongbo , Zheng Jian , Zhu Shaoping
Published: June 2024

Proton radiography is a widely used experimental method to diagnose the electric and magnetic (EM) fields in high-energy-density plasmas. In proton radiography, the probe protons are typically assumed to be deflected only by the EM fields, whereas the Coulomb scattering caused by the charged particles in the target plasmas is generally ignored. However, at high plasma densities, the presence of Coulomb scattering could reduce the proton flux perturbations recorded on the detector and influence the inversion of the EM fields from experiments. In this paper, a theoretical model is developed for the first time to describe the proton flux distribution on the detector when the EM field deflections and Coulomb scattering coexist in deflecting the probe proton trajectories. Our theory indicates that the Coulomb scattering could decrease the signal contrast of the probed EM fields, which is determined not only by the strengths of the EM field deflections and Coulomb scattering but also by the spatial gradient of the EM fields. Monte Carlo simulations are also conducted to validate our theoretical model. It would be helpful to interpret the proton radiography experiments quantitatively.
Learning mappings of thermal updraft fields under unknown operating conditions using a deep operator network
Authors: Wang Danxiang , Xie Fangfang , Ji Tingwei , Meng Xuhui , Zheng Yao
Published: June 2024

Precise estimation of the thermal updraft environment is important for the effective exploration of wind resources in long-endurance drones. Nevertheless, previous regression algorithms exhibit limitations in accurately evaluating updrafts under new operating conditions, and traditional airborne wind measurement methods are constrained by narrow ranges and sparse spatial sampling. This study addresses these challenges by harnessing continuous temperature data acquired via infrared sensors. The proposed methodology employs a data-driven deep operator network (DeepONet) to map the temperature field to the velocity field. Numerical simulations of two-dimensional Rayleigh–Bénard convection are conducted to simulate sensing measurements under various Rayleigh number Ra, used as both training and testing datasets. For the DeepONet framework, a convolutional neural network (CNN) structure is employed as the branch network to extract features from the temperature field. Simultaneously, a fully connected neural network (FNN) is adopted as the trunk network, encoding input functions from fixed sensors. In order to assess the estimation performance in new environments, the training data are under operating conditions within the range of Ra=3×107–6×107, and the testing data are under other unknown operating conditions. By compared to the conventional FNN network and the standard DeepONet framework, the DeepONet(CNN) in this study manifests a significant enhancement in estimation performance, demonstrating improvements ranging from 20% to 40% under unknown operating conditions.
Reconstruction of magnetic island electron temperature in mixed second and third harmonic electron cyclotron emission conditions
Authors: Jung E. , Bardóczi L. , Austin M. E. , Son S. H. , Reiman A. H.
Published: June 2024

We develop a method to use the mixed third and second harmonic electron cyclotron emission (ECE) signal in the DIII-D tokamak to reconstruct the electron temperature profile of a rotating magnetic island. The third harmonic ECE is removed by extracting the rotating-island-associated fluctuations in the mixed signal, and the extracted fluctuation is combined with the equilibrium temperature obtained from other diagnostics after correcting for the third harmonic reabsorption. The accuracy of the reconstruction is studied by considering a DIII-D shot where an unmixed signal from an island is available on the low field side of the plasma and a mixed signal from the same island is available from the high field side. It is found that the reconstruction method successfully reproduces the island shape and temperature perturbation magnitude without the distortion caused by third harmonic ECE mixing. However, the radial location of the reconstructed island is somewhat displaced relative to the location of the q = 2 surface in the axisymmetric equilibrium reconstruction, resulting in a corresponding inaccuracy in the absolute temperature of the island. It is conjectured that this may arise from an inaccuracy of the reconstructed axisymmetric equilibrium in this region.
Numerical simulation of evolution pattern of vortices in Taylor–Couette flow with three-lobe multiwedge clearance
Authors: Luo Bi-tai , Zhang Jing-yang , Cheng Feng-na , Lyu Yuan-wei
Published: June 2024

Gas foil bearings have been utilized in high-speed rotational machinery due to their superiority of load capacity and stability, which are closely associated with the shearing flow induced by variable sections in multiwedge clearance. This study focuses on the evolution pattern of vortices in Taylor–Couette flow with three-lobe multiwedge clearance using large-eddy simulation. As the Taylor number (Ta) increases, the shearing flow transitions from separation flow to Taylor vortex flow, followed by secondary transitions leading to wavy vortex flow. Separation vortices occur around the joint between two lobes, significantly delaying the first transition. Subsequently, Taylor vortices emerge and interact with the separation vortices, resulting in a complex evolution pattern of vortex series with increasing Ta. The presence of separation vortices promotes the formation of angular periodicity in Taylor vortices, accelerating the occurrence of angular periodicity stall and enhancing energy exchange between adjacent Taylor vortices. Taylor vortices are prone to breaking and merging. Additionally, Taylor vortices disrupt the shear layer of separation vortices between the stall region and the mid-radius separation region, leading to the migration of the shear layer and the singularity toward the mid-radius. Consequently, separation vortices move toward the mid-radius and transform from a one main vortex structure to two main vortex structures. Furthermore, spectral analysis of turbulent kinetic energy (TKE) reveals an inverse energy cascade characteristic with a slope of −7/3 at high frequencies, attributed to the TKE transmission between Taylor vortices and separation vortices. Both types of vortices exhibit intermittent and periodic behavior.
Interplay of roughness and wettability in microchannel fluid flows—Elucidating hydrodynamic details assisted by deep learning
Authors: Mondal Nilanjan , Arya Vinay , Sarangi Paritosh , Bakli Chirodeep
Published: June 2024

Under microconfinement, the complex interaction between surface roughness and fluid slippage yields unexpected variations in friction factor and drag reduction. These variations arise from the combined effects of roughness and hydrophobic interactions of the surface with the hydrodynamic field. Our study investigates alterations in frictional characteristics within long microchannels, considering fluid slippage, hydraulic diameter, and roughness. This exploration holds promise for precise drag reduction control applications for lab-on-a-chip and small-scale devices. To address computational limitations in analyzing diverse hydrodynamic conditions, we employ an artificial neural network prediction model, validated with experimental and numerical results. Contrary to the macroscopic conclusions obtained from the Moody chart, our findings indicate that fluid slippage, apart from surface roughness, significantly influences the friction factor. The interdependencies of friction factor on the flow and fluid parameters are thoroughly studied toward the proposition of a new slip-modified constricted flow friction factor formula, predicting friction in microchannels with combined roughness and hydrophobicity effects. This combined numerical and machine-learning approach presents a noteworthy counterpart to the moody chart at microscales offering the potential for a unified continuum-based description to include interfacial effects.
Charge trapping layer enabled high-performance E-mode GaN HEMTs and monolithic integration GaN inverters
Authors: Jiang Yang , Du FangZhou , Wen KangYao , He JiaQi , Wang PeiRan , Li MuJun , Tang ChuYing , Zhang Yi , Wang ZhongRui , Wang Qing , Yu HongYu
Published: June 2024

In this work, high threshold voltage and breakdown voltage E-mode GaN HEMTs using an Al:HfOx-based charge trapping layer (CTL) are presented. The developed GaN HEMTs exhibit a wide threshold modulation range of ΔVTH ∼ 17.8 V, which enables the achievement of enhancement-mode (E-mode) operation after initialization process owing to the high charge storage capacity of the Al:HfOx layer. The E-mode GaN HEMTs exhibit a high positive VTH of 8.4 V, a high IDS,max of 466 mA/mm, a low RON of 10.49 Ω mm, and a high on/off ratio of ∼109. Moreover, the off-state breakdown voltage reaches up to 1100 V, which is primarily attributed to in situ O3 pretreatment effectively suppressing and blocking leakage current. Furthermore, thanks to the VTH of GaN HEMTs being tunable by initialization voltage using the proposed CTL scheme, we prove that the direct-coupled FET logic-integrated GaN inverters can operate under a variety of conditions (β = 10–40 and VDD = 3–15 V) with commendable output swing and noise margins. These results present a promising approach toward realizing the monolithic integration of GaN devices for power IC applications.
Numerical analysis of flash-boiling spray characteristics with liquid ammonia
Authors: Wang Jieming , Wang Hu , Zheng Zunqing , Yao Mingfa
Published: June 2024

Liquid ammonia is a promising clean fuel, but it has a greater tendency to flash-boil than conventional fuels. This study confirms the reliability of utilizing the Eulerian framework and homogeneous relaxation model for simulating flash-boiling liquid ammonia sprays by comparing the simulation results with experimental data. The characteristics of single-hole superheated liquid ammonia sprays are analyzed for different orifice aspect ratios and superheat degrees. The results indicate that superheat degree and orifice aspect ratio affect the external spray morphology by affecting the two-phase flow inside the orifice. The strong phase transition due to flash-boiling drives the spray expansion process and increases the velocity. Moreover, the extensive bubble breakup in flash-boiling sprays promotes faster atomization. However, flash-boiling also results in a more pronounced temperature drop in the spray zone. This research can provide valuable insights for future simulations and engineering practices involving flash-boiling ammonia sprays.
Predictability of decaying stratified turbulence
Authors: Diaz Martin F. , Waite Michael L.
Published: June 2024

Predictability of geophysical fluid dynamics at various scales remains a crucial challenge for accurate weather and climate forecasting. Following the pioneering framework established by Lorenz, numerous studies on homogeneous and isotropic turbulence have demonstrated that flows characterized by diverse scales may exhibit limited predictability. This limitation arises from the inevitable amplification of errors in the initial conditions from small scales to larger scales, even if the initial error is confined to small scales. This research investigates the predictability of freely decaying homogeneous stratified turbulence, which serves as a representative model for small-scale geophysical turbulence where rotational effects are negligible. Direct numerical simulations are employed to assess predictability by analyzing the growth of errors introduced in pairs of simulations with near-identical initial conditions; errors are modeled as the difference field of the pair. Previous studies have established a connection between the finite range of predictability and the slope of the kinetic energy spectrum. In the context of stratified turbulence, the shape of the energy spectrum exhibits a dependence on the buoyancy Reynolds number (Reb), particularly at lower values of Reb. This work conducts a comparative analysis of both the energy spectra and the error growth behavior across different regimes of stratified turbulence, encompassing a range of Reb values from O(1) to O(10). The sensitivity of the obtained results to the introduced error is investigated. Modifying the geometrical shape of the error (spherical vs cylindrical complement) and the cutoff wavenumber while maintaining the initial error kinetic energy did not significantly alter the error dynamics. The results are robust to variations in the method of error introduction.
Asymptotic expansions and scaling of turbulent boundary layers in adverse pressure gradients
Authors: Ma Mingze , Bai Ruijie , Song Hanqi , Zhang Jinrong , Yan Chao
Published: June 2024

This paper presents an outer velocity scale and an inner scaling law of Reynolds shear stresses that are valid for the entire adverse pressure gradient (APG) region before separation, based on asymptotic expansions in turbulent boundary layers (TBLs). By reexamining the velocity defect and Reynolds shear stress in the outer region of TBLs, it is demonstrated that the pressure gradient effect can be included in asymptotic expansions. The mathematical requirements to be satisfied by the outer velocity scale are given. On this basis, we define a new outer velocity scale Uo, which is used in the mean momentum balance analysis over the entire APG region. The results show that there is a slowly evolving region of the Reynolds shear stress gradient in APG TBLs. We obtain a logarithmic decay law for the Reynolds stress gradient by asymptotic matching in this region, thus providing functional expressions for the total shear stress and total shear stress gradient in the inner region of TBLs. These expressions are valid for the entire APG region. Furthermore, we use the new velocity scale to determine three self-similar parameters in the momentum equation to discuss the conditions for approximate equilibrium. The changes in parameters point to changes in two physical properties of APG TBLs, the inertial force and turbulence production.
Origin of self-induced unsteadiness in axial compressors
Authors: Xie Hong , Xiao Zuling , Wang Libo , Wang Chunrong , Lin Zhihong
Published: June 2024

This study investigated the instability mechanisms within the blade-tip region of a transonic compressor. The variations in these mechanisms were explored under different operating conditions using methods such as spectral analysis and vortex identification. The results and analysis enhance the comprehension of self-excited unsteadiness in axial compressors, identifying its initiation characteristics and prevalence under different operational conditions. The regular occurrence of self-excited pulsations in transonic rotors was confirmed, especially when the flow rates fall blow specific levels, causing spontaneous pulsations within the tip region that are notably different from the blade-passing frequency. The findings highlight the crucial influence of interactions between separation flow, leakage flow, and shock waves in generating these pulsations. The effects of clearance size on flow structure intensity were also categorized, revealing three distinct self-excited unsteadiness mechanisms. These range from pulsations caused by shock–boundary-layer separation at small clearance sizes to those induced by interactions between leakage flow and shock waves at larger clearances, and finally to pulsations initiated directly by the clearance vortices at significantly larger clearances. This detailed analysis provides valuable insights into the dynamics of self-excited unsteadiness, supporting the advancement of the design and performance optimization of compressors.
Rapidly strained metals strengthen when heated
Authors: Lopatka Alex
Published: June 2024

In high-temperature microballistic experiments, rapidly strained copper is about as strong as steel.
Maternal care leads to the evolution of long, slow lives
Authors: Zipple Matthew N. , Reeve H. Kern , Peniston Orca Jimmy
Published: June 2024

Animals, and mammals in particular, vary widely in their “pace of life,” with some species living long lives and reproducing infrequently (slow life histories) and others living short lives and reproducing often (fast life histories). These species also vary in the importance of maternal care in offspring fitness: In some species, offspring are fully independent of their mothers following a brief period of nutritional input, while others display a long period of continued dependence on mothers well after nutritional dependence. Here, we hypothesize that these two axes of variation are causally related to each other, such that extended dependence of offspring on maternal presence leads to the evolution of longer lives at the expense of reproduction. We use a combination of deterministic modeling and stochastic agent-based modeling to explore how empirically observed links between maternal survival and offspring fitness are likely to shape the evolution of mortality and fertility. Each of our modeling approaches leads to the same conclusion: When maternal survival has a strong impact on the survival of offspring and grandoffspring, populations evolve longer lives with less frequent reproduction. Our results suggest that the slow life histories of humans and other primates as well as other long-lived, highly social animals such as hyenas, whales, and elephants are partially the result of the strong maternal care that these animals display. We have designed our models to be readily parameterized with demographic data that are routinely collected by long-term researchers, which will facilitate more thorough testing of our hypothesis.
Signaling proteins in HSC fate determination are unequally segregated during asymmetric cell division
Authors: Ugale Amol , Shunmugam Dhanlakshmi , Pimpale Lokesh G. , Rebhan Elisabeth , Baccarini Manuela
Published: June 2024

Hematopoietic stem cells (HSCs) continuously replenish mature blood cells with limited lifespans. To maintain the HSC compartment while ensuring output of differentiated cells, HSCs undergo asymmetric cell division (ACD), generating two daughter cells with different fates: one will proliferate and give rise to the differentiated cells’ progeny, and one will return to quiescence to maintain the HSC compartment. A balance between MEK/ERK and mTORC1 pathways is needed to ensure HSC homeostasis. Here, we show that activation of these pathways is spatially segregated in premitotic HSCs and unequally inherited during ACD. A combination of genetic and chemical perturbations shows that an ERK-dependent mechanism determines the balance between pathways affecting polarity, proliferation, and metabolism, and thus determines the frequency of asymmetrically dividing HSCs. Our data identify druggable targets that modulate HSC fate determination at the level of asymmetric division.
Casimir wormholes in Brans–Dicke theory
Authors: Hadi Ziaie Amir , Reza Mehdizadeh Mohammad
Published: June 2024

In recent years there has been a growing interest in the field of wormhole physics in the presence of Casimir effect. As this effect provides negative energy density, it can be utilized as an ideal candidate for the exotic matter required for creating a traversable wormhole. In the context of modified theories of gravity such as Brans–Dicke (BD) theory (Brans and Dicke 1961 Phys. Rev.
124 925), wormhole geometries have been vastly investigated. However, the scientific literature is silent on the issue of BD wormholes in the presence of Casimir energy. Our aim in the present study is to seek for static spherically symmetric solutions representing wormhole configurations in BD theory with Casimir energy as the supporting matter. The Casimir setup we assume comprises two electrically neutral, infinitely large parallel planes placed in a vacuum. We then consider the Casimir vacuum energy density of a scalar field in such a configuration with Dirichlet and mixed boundary conditions. In the former case the corresponding Casimir force is attractive and in the latter this force is repulsive. We present exact zero tidal force wormhole solutions as well as those with non vanishing redshift function for both types of Casimir energies. The conditions on wormhole solutions along with the weak (WEC) and null (NEC) energy conditions put constraints on the values of BD coupling parameter. These constraints are also subject to the value of BD scalar field at the throat and the throat radius. We therefore find that BD wormholes in the presence of Casimir energy can exist without violating NEC and WEC (for the repulsive Casimir force). Finally, we examine the equilibrium condition for stability of the obtained solutions using Tolman–Oppenheimer–Volkoff equation.
High energy neutral atom emission from rear side of foils
Authors: Tata Sheroy , Sabui Ratul , Mondal Angana , Sarkar Soubhik , Lad Amit D , Krishnamurthy M
Published: June 2024

Intense laser pulses focused onto a solid micron foil target are best known for generation of large electrostatic sheath fields at the target rear and acceleration of protons to MeV energies. The fact that such acceleration schemes also generate fast neutral atoms has received comparatively less attention. A quantitative assessment of the neutralization fraction reveals novel and often unexpected aspects of electron-ion interaction in regions far from dense plasmas. At the rear side of laser irradiated foil, a few hundred keV accelerated neutral Hydrogen atoms are observed. Neutralisation fraction is much larger than that anticipated from the collisional charge transfer and is about 300% larger for ions of

⩽

100 keV energy. Corroborated by particle-in-cell simulations, the larger neutralisation fraction is attributed to electron-recombination as the protons co-propagate with the low energy electrons.
NiO thin films fabricated using spray-pyrolysis technique: structural and optical characterization and ultrafast charge dynamics studies
Authors: Das Lakshmi , Canto-Aguilar Esdras J , Tapani Tlek , Lin Haifeng , Bhuvanendran Hinduja , Boulanger Nicolas , Salh Roushdey , Gracia-Espino Eduardo , Maccaferri Nicolò
Published: June 2024

Nickel (II) oxide, NiO, is a wide band gap Mott insulator characterized by strong Coulomb repulsion between d-electrons and displays antiferromagnetic order at room temperature. NiO has gained attention in recent years as a very promising candidate for applications in a broad set of areas, including chemistry and metallurgy to spintronics and energy harvesting. Here, we report on the fabrication of polycrystalline NiO using spray-pyrolysis technique, which is a deposition technique able to produce quite uniform films of pure and crystalline materials without the need of high vacuum or inert atmospheres. The composition and structure of the NiO thin films were then studied using x-ray diffraction, and atomic force and scanning electron microscopies (SEM). The phononic and magnonic properties of the NiO thin films were also studied via Raman spectroscopy, and the ultrafast electron dynamics by using optical pump probe spectroscopy. We found that the NiO samples display the same phonon and magnon excitations expected for single crystal NiO at room temperature, and that electron dynamics in our system is like those of previously reported NiO mono- and polycrystalline systems synthesized using different techniques. These results prove that spray-pyrolysis can be used as affordable and large-scale fabrication technique to synthesize strongly correlated materials for a large set of applications.
Solute segregation in a moving grain boundary: a phase-field approach
Authors: Guin Sandip , Verma Miral , Bandyopadhyay Soumya , Lo Yu-Chieh , Mukherjee Rajdip
Published: June 2024

We present a phase-field approach for investigating monolayer and multilayer type solute segregation in a moving Grain boundary (GB). In this model, we introduce an expression for the GB solute interaction potential which allows for easy modification of the shape of the solute segregation profile at the GB. As a consequence, our phase-field simulations capture various segregation profiles in both stationary and migrating GB that agree with Cahn’s solute drag theory. Furthermore, we explore how different segregation profiles evolve at varying GB velocities owing to the inequality of the atomic flux of solute between the front and back faces of the moving GB. At a low-velocity regime, we observe that multilayer segregation results in significantly increased drag force compared to monolayer segregation. At a high-velocity regime, the opposite holds. Our simulation results also provide valuable insights for predicting grain growth in polycrystalline materials in the presence of solute segregation.
Corrigendum: A new look at orbits (2024 Phys. Educ.
59 023002)
Authors: Hughes Stephen
Published: June 2024

Figure 2 is updated.
A high-throughput focused collimator for OAR-sparing preclinical proton FLASH studies: commissioning and validation
Authors: Mossahebi Sina , Byrne Kevin , Jiang Kai , Gerry Andrew , Deng Wei , Repetto Carlo , Jackson Isabel L , Sawant Amit , Poirier Yannick
Published: June 2024

Objective. To fabricate and validate a novel focused collimator designed to spare normal tissue in a murine hemithoracic irradiation model using 250 MeV protons delivered at ultra-high dose rates (UHDRs) for preclinical FLASH radiation therapy (FLASH-RT) studies. Approach. A brass collimator was developed to shape 250 MeV UHDR protons from our Varian ProBeam. Six 13 mm apertures, of equivalent size to kV x-ray fields historically used to perform hemithorax irradiations, were precisely machined to match beam divergence, allowing concurrent hemithoracic irradiation of six mice while sparing the contralateral lung and abdominal organs. The collimated field profiles were characterized by film dosimetry, and a radiation survey of neutron activation was performed to ensure the safety of staff positioning animals. Main results. The brass collimator produced 1.2 mm penumbrae radiation fields comparable to kV x-rays used in preclinical studies. The penumbrae in the six apertures are similar, with full-width half-maxima of 13.3 mm and 13.5 mm for the central and peripheral apertures, respectively. The collimator delivered a similar dose at an average rate of 52 Gy s−1 for all apertures. While neutron activation produces a high (0.2 mSv h−1) initial ambient equivalent dose rate, a parallel work-flow in which imaging and setup are performed without the collimator ensures safety to staff. Significance. Scanned protons have the greatest potential for future translation of FLASH-RT in clinical treatments due to their ability to treat deep-seated tumors with high conformality. However, the Gaussian distribution of dose in proton spots produces wider lateral penumbrae compared to other modalities. This presents a challenge in small animal pre-clinical studies, where millimeter-scale penumbrae are required to precisely target the intended volume. Offering high-throughput irradiation of mice with sharp penumbrae, our novel collimator-based platform serves as an important benchmark for enabling large-scale, cost-effective radiobiological studies of the FLASH effect in murine models.
Feasibility of identifying proliferative active bone marrow with fat fraction MRI and multi-energy CT
Authors: Lawless M , Byrns K , Bednarz B P , Meudt J , Shanmuganayagam D , Shah J , McMillan A , Li K , Pirasteh A , Miller J
Published: June 2024

Objective. Active bone marrow (ABM) can serve as both an organ at risk and a target in external beam radiotherapy. 18F-fluorothymidine (FLT) PET is the current gold standard for identifying proliferative ABM but it is not approved for human use, and PET scanners are not always available to radiotherapy clinics. Identifying ABM through other, more accessible imaging modalities will allow more patients to receive treatment specific to their ABM distribution. Multi-energy CT (MECT) and fat-fraction MRI (FFMRI) show promise in their ability to characterize bone marrow adiposity, but these methods require validation for identifying proliferative ABM. Approach. Six swine subjects were imaged using FFMRI, fast-kVp switching (FKS) MECT and sequential-scanning (SS) MECT to identify ABM volumes relative to FLT PET-derived ABM volumes. ABM was contoured on FLT PET images as the region within the bone marrow with a SUV above the mean. Bone marrow was then contoured on the FFMRI and MECT images, and thresholds were applied within these contours to determine which threshold produced the best agreement with the FLT PET determined ABM contour. Agreement between contours was measured using the Dice similarity coefficient (DSC). Main results. FFMRI produced the best estimate of the PET ABM contour. Compared to FLT PET ABM volumes, the FFMRI, SS MECT and FKS MECT ABM contours produced average peak DSC of 0.722 ± 0.080, 0.619 ± 0.070, and 0.464 ± 0.080, respectively. The ABM volume was overestimated by 40.51%, 97.63%, and 140.13% by FFMRI, SS MECT and FKS MECT, respectively. Significance. This study explored the ability of FFMRI and MECT to identify the proliferative relative to ABM defined by FLT PET. Of the methods investigated, FFMRI emerged as the most accurate approximation to FLT PET-derived active marrow contour, demonstrating superior performance by both DSC and volume comparison metrics. Both FFMRI and SS MECT show promise for providing patient-specific ABM treatments.
Implementation of tunable frequency-dependent stiffness elements via integrated shunted piezoelectric stacks
Authors: Van Damme B , Weber R , Schmied J U , Spierings A , Bergamini A
Published: June 2024

Piezoelectric transducers applied on or integrated in structures, combined with appropriate circuits have been extensively investigated as a smart approach to the mitigation of resonant vibrations with high relative amplitudes. A resonant shunt circuit consisting of the capacitive piezoelectric transducer and an inductance can be configured to target specific eigenmodes of a structure, if appropriately placed and tuned. Their effect is expressed in terms of mechanical impedance of the host structure, allowing for the exchange of energy between the mechanical and electrical domain, to dramatically affect the dynamic response of the structure. By re-framing the function of resonant shunted piezoelectric transducers as frequency dependent variable stiffness elements, this paper investigates their capability to realize a frequency dependent structural mechanical connectivity, where the load path within a lattice structure can be interrupted at will for specific frequencies by tunable null-stiffness components. Here, we offer the numerical and experimental verification of this idea, by demonstrating the ability to significantly affect the dynamic response of a unit cell of an adaptive lattice metamaterial, even away from a structural resonance. In the latter case, the null-stiffness shunt leads to an additional resonance peak in the truss’ dynamic response. Its realization as additively manufactured component points to the feasibility of such structures in real life.
An improved dynamic Prandtl–Ishlinskii hysteresis model and a PID-type adaptive sliding mode controller for piezoelectric micro-motion platform
Authors: Yang Silong , Wang Wen , Wang Ruijin , Bao Lei , Wang Dengjun , Lu Keqing , Chen Zhanfeng , Wang Chuanyong
Published: June 2024

Piezoelectric actuators are widely used in the field of micro-nano driving due to their advantages of fast frequency response, high displacement resolution, large stiffness, small size, and low heat generation. However, the hysteresis non-linearity of piezoelectric actuators severely affects their positioning accuracy during operation. Therefore, the study of hysteresis model and compensation control for piezoelectric actuators has always been a hot topic in the field of micro-nano driving. However, existing hysteresis models and control methods cannot well describe the dynamic hysteresis curve of piezoelectric actuators and track the desired trajectory. To address this issue, this paper proposes an improved dynamic Prandtl–Ishlinskii (IDPI) model and a finite-time trajectory tracking adaptive sliding mode control method based on PID-type. Firstly, this paper introduces the construction and parameter identification method of the IDPI model. Secondly, the accuracy of the IDPI model in describing hysteresis curves under different input signals is verified through experiments, and the effectiveness of the feedforward controller based on the IDPI model is validated experimentally. Then, considering the modeling uncertainty, unmodeled internal dynamics, and external environmental disturbances of the piezoelectric micro-motion platform, a finite-time trajectory tracking adaptive sliding mode controller based on PID-type is designed to suppress the non-linear characteristics of the piezoelectric micro-motion platform. Finally, the performance of the compensator is verified through simulation experiments.
Unveiling highly sensitive Dy3+ doped BaMgAl10O17 phosphor’s thermoluminescence trap features and temperature dependent luminescence for solid state lighting applications
Authors: A Vidya Saraswathi , Chennappa Tejas , Naregundi Karunakara , Princy A , Kennedy S Masilla Moses , Altowyan Abeer S , Sayyed M I , Kamath Sudha D
Published: June 2024

This article explores the structural, morphological, thermoluminescence, and temperature-dependent emission properties of novel Dy3+ doped BaMgAl10O17(BAM-Dy) phosphors. Structural studies reveal that the phosphor has a similar structure to β-alumina. Rod-shaped interlinked surface morphology is a notable characteristic of the BAM-Dy samples. Incorporation of Dy3+ ions lead to the formation of distinct emission peaks (485 nm, 577 nm, and 635 nm) in the PL emission spectra. The effect of dopant concentration on the light output is crucial, and the highest PL intensity is observed for 1.5 mol% of Dy3+ concentration. The potential use of BAM-Dy phosphors for Gamma radiation detection and measurement is tested through thermoluminescence studies, which reveal high sensitivity, low threshold dose values, and exceptional response to low gamma doses, making them suitable for dosimetry applications. The investigation of trap parameters provides useful information about the number of traps, trapping mechanism, and trap energies, which is essential for in-depth study of synthesized phosphors for γ dosimetry application. The study of the effect of temperature on the luminescence behaviour is crucial for the application of phosphors in the light-emitting field. The BAM-Dy samples exhibit excellent thermal stability even at 210 °C, making them suitable for use in the field of White LEDs.
Core-excited states in 105Cd
Authors: Ivanova D , Lalkovski S , Atanasova L , Kisyov S , Vasilev I , Mihai C , Turturica A , Blazhev A , Borcea R , Boromiza M , Calinescu S , Clisu Stan C , Costache C , Gandhi A , Grigorova D , Lica R , Marginean N , Marginean R , Müller-Gatermann C , Olacel A , Petrov N L , Stan L , Stefanova E A , Stiru I , Stoev G , Toma S , Turturica G , Ujeniuc S , Yordanov O
Published: June 2024

105Cd was produced in the 96Mo+12C fusion/evaporation reaction, performed at NIPNE, Bucharest-Magurele, Romania. Various excited states of positive- and negative-parities were populated. Picosecond half-lives were measured by using the Differential Decay Curve Method (DDCM) method, allowing to control the side feeding of the states of interest. New data were obtained for the half-lives of the 11/2+, 15/2− and 19/2−
105Cd states. Reduced electric quadrupole transition strengths were calculated and compared to the neighboring odd-A and even-A cadmium nuclei. The particle-core weak coupling approach was used to interpret excited states of 105Cd in the light of the new data.
Urine glucose concentration detection biosensor using one-dimensional photonic crystals with periodical and Fibonacci sequences based on Tamm plasmon resonance
Authors: Huang Xing , Zhang Liwei , Chen Xiaolin , Shi Rui
Published: June 2024

This paper presents the design of biosensors utilizing one-dimensional photonic crystals with periodical and Fibonacci sequences for measuring glucose concentration in urine, aimed at facilitating continuous blood glucose monitoring for diabetic patients. Exploiting Tamm plasmon resonance within a photonic band gap in the medium wave infrared band, the biosensor comprises a configuration with a one-dimensional photonic crystal and an Ag layer deposited on an infrared prism, with a urine sample layer in between. Utilizing the transfer matrix method, the reflection spectra for electromagnetic waves are calculated. The wavelength position of the Tamm plasmon resonant dip is influenced by variations in glucose concentration within the urine sample. This is attributed to the distinct refractive indices exhibited by urine samples with different glucose concentrations. Optimizing biosensor performance under various incident angles involves adjusting the Ag layer and urine sample thicknesses while maintaining excellent linear characteristics. The optimal performance of the biosensor with Fibonacci sequence one-dimensional photonic crystal is significantly superior, with a sensitivity of 113,000 nm RIU−1, a figure of merit of 2.05 × 105 RIU−1, and a detection limit of 4.84 × 10−7 RIU. The combination of high performance and a straightforward structure makes the proposed biosensors for detecting urine glucose concentrations promising in biomedical diagnostics.
Stable dynamic helix state in the nonintegrable XXZ Heisenberg model
Authors: Zhang G , Song Z
Published: June 2024

We investigate the influence of external fields on the stability of spin helix states in an XXZ Heisenberg model. Exact diagonalization on a finite system shows that random transverse fields in the x and y directions drive the transition from integrability to nonintegrability. In such a system, the helix state can be regarded as a quantum scar. Simultaneously, the presence of uniform z field enables the helix state to better maintain its dynamical nature, allowing for a clearer understanding of its evolutionary behavior. However, the entanglement entropy reveals that irrespective of the presence of a uniform z field, as long as the system remains chaotic, the scar extent of the helix state shows no significant variation.