bluuebunny/crossref_metadata_2025 huggingface dataset:
Active dynamics of linear chains and rings in porous media
Authors: Theeyancheri Ligesh , Chaki Subhasish , Bhattacharjee Tapomoy , Chakrabarti Rajarshi
Published: July 2023

To understand the dynamical and conformational properties of deformable active agents in porous media, we computationally investigate the dynamics of linear chains and rings made of active Brownian monomers. In porous media, flexible linear chains and rings always migrate smoothly and undergo activity-induced swelling. However, semiflexible linear chains though navigate smoothly, shrink at lower activities, followed by swelling at higher activities, while semiflexible rings exhibit a contrasting behavior. Semiflexible rings shrink, get trapped at lower activities, and escape at higher activities. This demonstrates how activity and topology interplay and control the structure and dynamics of linear chains and rings in porous media. We envision that our study will shed light on understanding the mode of transport of shape-changing active agents in porous media.
In situ cathode-electrolyte interphase enables high cycling stability of Co-free Li-rich layered cathodes
Authors: Vahdatkhah Parisa , Sadrnezhaad Sayed Khatiboleslam , Voznyy Oleksandr
Published: July 2023

Despite the extensive research in Li-rich layered oxides (LLOs), which are promising candidates for high-energy density cathodes, their cycle life still cannot meet the real-world application requirements. The poor cycle performance arises from the electrolyte decomposition at high voltage, resulting in damage and subsequent surface-initiated conversion of the cathode from layered to spinel phase. This problem is even more challenging for Co-free LLO cathodes. Here, we report a one-pot synthesis of in situ carbonate-coated nanostructured Co-free LLO (Li2CO3@LLO) through a polyol-assisted method. This inorganic coating suppresses oxygen release, provides good Li–ion transport, and protects the cathode from adverse reactions with the electrolyte. The obtained material exhibits excellent long-term stability, with 76% capacity retention after 1000 cycles at a 0.2 C rate without any Co addition, demonstrating a path forward for using LLOs as a next-generation Li–ion battery cathode.
Electrostatic hindrance to diffusion in flexible crosslinked gels: A coarse-grained simulation study
Authors: Pérez-Mas Luis , Ramos-Tejada María del Mar , Martín-Molina Alberto , Maroto-Centeno José-Alberto , Quesada-Pérez Manuel
Published: July 2023

In this work, we study how electrostatic forces slow down the diffusion of solute in flexible gels through coarse-grained simulations. The model used explicitly considers the movement of solute particles and polyelectrolyte chains. These movements are performed by following a Brownian dynamics algorithm. The effect of three electrostatic parameters characterizing the system (solute charge, polyelectrolyte chain charge, and ionic strength) is analyzed. Our results show that the behavior of both the diffusion coefficient and the anomalous diffusion exponent changes upon the reversal of the electric charge of one of the species. In addition, the diffusion coefficient in flexible gels differs significantly from that in rigid gels if the ionic strength is low enough. However, the effect of chain flexibility on the exponent of anomalous diffusion is significant even at high ionic strength (100 mM). Our simulations also prove that varying the polyelectrolyte chain charge does not have exactly the same effect as varying the solute particle charge.
Fast ion effects on zonal flow generation: A simple model
Authors: Hahm T. S. , Choi G. J. , Park S. J. , Na Y.-S.
Published: July 2023

Fast ions' effects on turbulence-driven zonal flow generation are investigated in the context of a simple reduced model based on the Hasegawa–Mima equation. Fast ions' much higher characteristic frequency of parallel motion in comparison with the drift wave's phase velocity along the magnetic field facilitates a derivation of the reduced model equations. Nonlinear mode coupling analyses show that the threshold amplitude of drift wave required for the zonal flow modulational instability is significantly reduced, making its generation easier. This occurs as both a down-shift of the drift wave's frequency and a reduction of dispersion in the presence of the fast ions cause a decrease in the mismatch between the primary drift wave frequency and the zonal flow modulated sideband drift wave's characteristic frequency. This finding could be a common nonlinear physics mechanism behind numerous recent results on tokamak plasma confinement enhancement caused by the fast ions.
Two-dimensional 4f magnetic EuSn2X2 (X = P, As) monolayers: A first-principles study
Authors: Bai Yihang , Wu Yaxuan , Jia Chaobin , Hou Lipeng , Wang Bing
Published: July 2023

Two-dimensional (2D) ferromagnetic semiconductors (FMSs) hold exciting and promising potential for application in spintronic devices at the nanoscale. Currently, most 2D FMSs are based on 3d electrons; 4f electrons can provide nontrivial magnetism but have been much less studied to date. This paper presents a theoretical study, via first-principles calculations, of EuSn2X2 (X = P, As) monolayers based on rare-earth cations with f-electrons. The results show that EuSn2X2 monolayers possess a large magnetization (7 μB/Eu), a controllable magnetic anisotropy energy, and a unique d-electron-mediated f–f exchange mechanism. Both types of EuSn2X2 (X = P, As) monolayers are FMSs with indirect bandgaps of 1.00 and 0.99 eV, respectively, based on the Heyd–Scuseria–Ernzerhof (HSE06) method, which can be transform to direct bandgap semiconductors under biaxial strain. Interestingly, under the latter, spin–orbit coupling interaction gradually replaces the dipole–dipole interaction in the dominant position of magnetic anisotropy, resulting in the magnetic easy axis changing from in-plane to the more desirable out-of-plane. Considering their excellent dynamic, thermal, and mechanical stabilities and small cleavage energy, these EuSn2X2 monolayers can be exfoliated from their synthesized bulk. Our study not only helps to understand the properties of 2D 4f rare-earth magnets but also signposts a route toward improving the performance of EuSn2X2 monolayers in nano-electronic devices.
Modified Fermi’s golden rule rate expressions
Authors: Jang Seogjoo J. , Rhee Young Min
Published: July 2023

Fermi’s golden rule (FGR) serves as the basis for many expressions of spectroscopic observables and quantum transition rates. The utility of FGR has been demonstrated through decades of experimental confirmation. However, there still remain important cases where the evaluation of a FGR rate is ambiguous or ill-defined. Examples are cases where the rate has divergent terms due to the sparsity in the density of final states or time dependent fluctuations of system Hamiltonians. Strictly speaking, assumptions of FGR are no longer valid for such cases. However, it is still possible to define modified FGR rate expressions that are useful as effective rates. The resulting modified FGR rate expressions resolve a long standing ambiguity often encountered in using FGR and offer more reliable ways to model general rate processes. Simple model calculations illustrate the utility and implications of new rate expressions.
Development of a compactAnsatzvia operator commutativity screening: Digital quantum simulation of molecular systems
Authors: Mondal Dibyendu , Halder Dipanjali , Halder Sonaldeep , Maitra Rahul
Published: July 2023

Recent advancements in quantum information and quantum technology have stimulated a good deal of interest in the development of quantum algorithms toward the determination of the energetics and properties of many-fermionic systems. While the variational quantum eigensolver is the most optimal algorithm in the noisy intermediate scale quantum era, it is imperative to develop compact Ansätze with low-depth quantum circuits that are physically realizable in quantum devices. Within the unitary coupled cluster framework, we develop a disentangled Ansatz construction protocol that can dynamically tailor an optimal Ansatz using the one- and two-body cluster operators and a selection of rank-two scatterers. The construction of the Ansatz may potentially be performed in parallel over multiple quantum processors through energy sorting and operator commutativity prescreening. With a significant reduction in the circuit depth toward the simulation of molecular strong correlation, our dynamic Ansatz construction protocol is shown to be highly accurate and resilient to the noisy circumstances of the near-term quantum hardware.
Anisotropic proton conduction in double-perovskite GdBaCo2O5.5
Authors: Katayama Tsukasa , Magara Kento , Chikamatsu Akira , Hasegawa Tetsuya
Published: July 2023

The proton-conductive properties of perovskite oxides have attracted attention for applications in sensors and neuromorphic devices. Recently, a unique two-dimensional proton conduction was theoretically predicted in the double-perovskite GdBaCo2O5.5 with a Gd/Ba order along the c-axis. To experimentally confirm the anisotropic proton conductivity, we prepared two types of GdBaCo2O5.5 epitaxial films with different crystal orientations: the films on NdGaO3(110) and SrTiO3(001) substrates had a Gd/Ba order along the in-plane and out-of-plane directions, respectively. Both the GdBaCo2O5.5 films were doped with protons via an electrochemical method under the same conditions at room temperature. From the reaction time dependence of the change in the lattice constants and proton depth profiles of the films, we found that the proton conductivity along the Gd/Ba order was slower than across it, which agreed well with theoretical calculations. The anisotropy of proton conductivity in GdBaCo2O5.5 probably originates from the BaO planes with large Ba2+ ions that hinder proton diffusion.
Study on the mechanical mechanism of dynamic wetting of sodium dodecyl sulfonate solutions containing inorganic salt additives
Authors: Zhang Junfeng , Liu Song , Feng He , Chen Liuyang , Tan Yuanhang , Xie Atian , Xue Changguo
Published: July 2023

Wettability is an important factor that influences surfactant oil displacement efficiency, where surfactant solutions wet rock surfaces better and have lower interfacial tensions with crude oil, thus enhancing the oil recovery rate. Therefore, understanding the wetting of rock surfaces and selecting suitable surfactant solutions are essential for enhanced oil recovery. In this paper, a self-built system to measure the lateral friction at solid and liquid interfaces was established, and the effects of different types and concentrations of inorganic salt additives on the dynamic wettability of the surfactant solution on the solid surface were studied. A rough silica surface was used to simulate the reservoir environment, and methylene chloride was used as the simulation oil. The experimental results show that when the concentration of sodium dodecyl sulfonate is lower than the critical micelle concentration, the inorganic salt additives (NaCl, Na2SO4, and KCl) affect the surface tension, contact angle, and lateral friction of the solution. As the concentration of the inorganic salt additives increased, the surface tension and contact angle of the solution continuously decreased, the lateral friction of the solution on the simulated silica surface increased, and the wettability of the surfactant solution on the solid surface improved.
The acoustic signature of a propeller–hydrofoil system in the far field
Authors: Posa A. , Broglia R. , Balaras E. , Felli M.
Published: July 2023

Data from Large-Eddy Simulations on a grid consisting of 3.8 billion points are utilized to reconstruct the acoustic far field of a propeller–hydrofoil system, using the Ffowcs-Williams and Hawkings acoustic analogy. Results demonstrate that the lowest frequencies, around the shaft frequency, are dominated by the sound coming from the surface of the downstream hydrofoil, especially in its normal direction. In contrast, at the blade frequency and higher frequencies, the acoustic signature of the upstream propeller gains the lead, especially in the upstream and downstream directions. Minima of the sound pressure levels correlate in all cases with the spanwise direction of the hydrofoil. Despite the dramatic change of the flow conditions for growing incidence angles of the hydrofoil, characterized by a substantial rise of the turbulent fluctuations on its suction side, no similar increase in the acoustic pressure in the far field occurs at large incidence angles, even at the onset of separation phenomena, which are able to affect the highest frequencies only.
Topology optimization design of broadband elastic wave coding metasurfaces
Authors: Liu Fei-Yu , Zhang Na-Li , Dong Hao-Wen , Wang Fa-Jie , Zhao Sheng-Dong
Published: July 2023

In this paper, a kind of broadband elastic wave coding metasurfaces is proposed. The metastructure unit designed by topology optimization is used as logical unit “1,” and the pure plate is set as logical unit “0.” The phase difference of the transmitted longitudinal wave between two units is introduced as the objective function in optimization. The transmittance of the designed unit is kept above 60%, and the transmitted phase difference between the two coding units is approximately π in the broadband frequency range. In addition, a set of achromatic focusing coding units is designed topologically to achieve customized dispersion. By coding the logical units, the designed metasurface can control the elastic wave between frequencies of 20.4 and 23.6 kHz, and wave performances, such as beam focusing and splitting, are achieved. The experimental results of the designed metasurface are in good agreement with numerical simulations. Therefore, our design has potential applications in the fields of engineering such as nondestructive testing.
Breakup of thin liquid films with viscous interfaces
Authors: Cunha Vitor Heitor C. , Ribeiro Sergio S. , Carvalho Marcio S.
Published: July 2023

Thin liquid films are ubiquitous in nature and have many practical applications. From biological films to the curtain coating process, thin films are present in both large and small scales. Despite their importance, understanding the stability of these films remains a significant challenge due to the fluid–fluid interface that is free to deform, affected by interfacial tension and complex rheological behavior. Instabilities in thin films are often caused by van der Waals attractions, which can lead to the rupture of the layer. To investigate the rupture dynamics, numerical methods are commonly used, such as asymptotic derivations of the lubrication theory or interface tracking methods. In this paper, we present a computational study of the breakup dynamics of a stationary thin liquid sheet bounded by a passive gas with a viscous interface, using the arbitrary Lagrangian–Eulerian method and the Boussinesq–Scriven constitutive law to model the rheological behavior. Our results demonstrate that the stability of thin liquid films is influenced by both surface rheology and disjoining effects and that the viscous character of the interface can delay sheet breakup, leading to more stable films.
Integrating planar circuits with superconducting 3D microwave cavities using tunable low-loss couplers
Authors: Zhao Ziyi , Gurra Eva , Rosenthal Eric I. , Vale Leila R. , Hilton Gene C. , Lehnert K. W.
Published: July 2023

We design and test a low-loss interface between superconducting three-dimensional microwave cavities and two-dimensional circuits, where the coupling rate is highly tunable. This interface seamlessly integrates a loop antenna and a Josephson junction-based coupling element. We demonstrate that the loss added by connecting this interface to the cavity is 1.28 kHz, corresponding to an inverse quality factor of 1/(4.5×106). Furthermore, we show that the cavity's external coupling rate to a 50 Ω transmission line can be tuned from negligibly small to over 3 orders of magnitude larger than its internal loss rate in a characteristic time of 3.2 ns. This switching speed does not impose additional limits on the coupling rate because it is much faster than the coupling rate. Moreover, the coupler can be controlled by low frequency signals to avoid interference with microwave signals near the cavity or qubit frequencies. Finally, the coupling element introduces a 0.04 Hz/photon self-Kerr nonlinearity to the cavity, remaining linear in high photon number operations.
Space-charge limited and ultrafast dynamics in graphene-based nano-gaps
Authors: Gröbmeyer J. , Zimmermann P. , Huet B. , Robinson J. A. , Holleitner A. W.
Published: July 2023

We show that nano-gaps formed in graphene by utilizing a focused helium ion beam can act as ultrafast photoswitches. By temperature-dependent, time-integrated, and ultrafast photocurrent measurements, we demonstrate that the optoelectronic dynamics across such nano-gaps are dominated by a space-charge limited current in combination with the ultrafast dynamics of hot electrons. The demonstrated methodology allows the creation of ultrafast photoswitches with an amplification gain exceeding the ones as formed by pristine graphene.
Predicting the electronic density response of condensed-phase systems to electric field perturbations
Authors: Lewis Alan M. , Lazzaroni Paolo , Rossi Mariana
Published: July 2023

We present a local and transferable machine-learning approach capable of predicting the real-space density response of both molecules and periodic systems to homogeneous electric fields. The new method, Symmetry-Adapted Learning of Three-dimensional Electron Responses (SALTER), builds on the symmetry-adapted Gaussian process regression symmetry-adapted learning of three-dimensional electron densities framework. SALTER requires only a small, but necessary, modification to the descriptors used to represent the atomic environments. We present the performance of the method on isolated water molecules, bulk water, and a naphthalene crystal. Root mean square errors of the predicted density response lie at or below 10% with barely more than 100 training structures. Derived polarizability tensors and even Raman spectra further derived from these tensors show good agreement with those calculated directly from quantum mechanical methods. Therefore, SALTER shows excellent performance when predicting derived quantities, while retaining all of the information contained in the full electronic response. Thus, this method is capable of predicting vector fields in a chemical context and serves as a landmark for further developments.
High-temperature phonon-assisted upconversion photoluminescence of monolayer WSe2
Authors: Meng Fengkai , Yang Xiaodong , Gao Jie
Published: July 2023

Phonon-assisted upconversion photoluminescence (UPL) is an anti-Stokes process emitting photons of energy higher than the excitation photons, with upconversion energy gain provided by optical phonons. Atomically thin transition metal dichalcogenides provide a promising platform for exploring the phonon-assisted UPL process due to their strong phonon–exciton interactions. Here, high-temperature phonon-assisted UPL process in monolayer WSe2 is investigated, aiming to understand the role of phonon population and the number of phonons involved in the UPL process at elevated temperatures. It is demonstrated that the integrated intensity of UPL emission significantly increases by two orders of magnitude as the temperature rises from room temperature of 295 to 476 K, which is distinguished from the photoluminescence emission usually suffering from thermal quenching. The observed growth of UPL emission intensity is attributed to both the increased phonon population and the reduced number of phonons required at elevated temperatures. Our study paves the way toward near-infrared light detection, anti-Stokes energy harvesting, optical refrigeration, and temperature sensing.
Evolution of surface recombination property of silicon wafers during laser irradiation by differential photocarrier radiometry
Authors: Chen Jing , Wang Qian , Tian Ailing , Wu Lingling
Published: July 2023

Understanding the surface recombination property of semiconductor materials is beneficial for improving the performance of optoelectronic devices. In this paper, differential photocarrier radiometry (PCR) is carried out to investigate the evolution of the surface recombination velocities of silicon wafers induced by laser irradiation. The PCR signal and the surface recombination velocities were found to be strongly dependent on the quality of the wafer surface and the duration of laser irradiation. The native oxide surface was more susceptible to laser irradiation than the Al2O3 passivated surface due to more surface defects being annealed. A surface-defect annealing model was used to explain the transient behavior of the PCR signal and the surface recombination velocity.
Origin of biased noise in one-time readout temporal single pixel imaging
Authors: Keyaki Ryota , Fukatsu Susumu
Published: July 2023

One-time readout temporal ghost imaging is a viable time-analog of single pixel imaging using a sluggish light receiver haunted by memory effects, which can be utilized to eliminate the need for steady watch and as such save computer clocks for data capturing and processing. Although the as-retrieved ghost image of a temporal object is modulated in proportion to the time-reversed impulse response function of the light receiver, it can be easily corrected by division. Nevertheless, inhomogeneously distributed noise plagues the images wildly, depending on the transmittance profile of an intensity-only object, which puzzles us. A coherent explanation is attempted for such apparently inconsistent behavior of the biased noise that develops even in simulation.
Thermodynamic Properties of Chlorine Dioxides and Chlorite Ions
Authors: Schmitz G.
Published: July 2023

An analysis of experimental measurements of the properties of chlorine dioxide gives ΔfG°(OClO·, g) = 116.3 ± 2.0, ΔfH°(OClO·, g) = 98.5 ± 2.0 kJ mol−1, ΔfG°(ClOO·, g) = 112.5 ± 1.5, and ΔfH°(ClOO·, g) = 98.3 ± 1.5 kJ mol−1. An analysis of OClO· solubility measurements gives Ksol = 1.01 ± 0.15 mol l−1 atm−1, ΔsolH = −28.9 ± 1.5 kJ mol−1, and ΔsolS = −96.9 ± 4 J mol−1 K−1. The uncertainties provided in this paper are expanded uncertainties U or 2 σ (95% confidence internal). These results and the redox potential E°(OClO·, aq/ClO2−, aq) = 0.935 ± 0.02 V give ΔfG°(ClO2−, aq) = 26.1 ± 4.0 kJ mol−1, value significantly larger than the value in the NBS Tables of Chemical Thermodynamic Properties.
Reprogrammable multistable ribbon kirigami with a wide cut
Authors: Yu Yang , Yin Yanqi , Bai Ruiyu , Hu Yunzhou , Li Bo , Wang Michael Yu , Chen Guimin
Published: July 2023

Upon stretching, a ribbon kirigami with parallel major cuts exhibits multistable behaviors that can maintain at multiple stable configurations. This work investigates the phenomena of a ribbon kirigami with one of the major cuts replaced by a wide cut, of which the multistable behaviors of the wide-cut located cell, the stable configurations, and the energy barriers between the stable configurations are explored. It is observed that the introduction of the wide cut results in local symmetry breaking, enabling bidirectional transition of the stable configurations in such a kirigami. The results also reveal that the geometries of major cuts and the stretch level enable reprogramable dynamic behaviors, such as the number of transitions once triggered. A kirigami-Morse code system is hereby presented, utilizing dynamic reconfiguration and showing a refreshable mechanical readout utilizing reprogrammability. The kirigami has potential for developing metamaterials with unique dynamic features.
Theoretical background of electron tunneling in electrochemical double layer
Authors: He Yitao , Shen Xiaoxiang
Published: July 2023

The electron tunneling or overflow in the electrochemical double layer has been mentioned in many previous reports, but its detailed influence mechanism is often neglected. In this work, we combined quantum chemistry and electrochemical double layer theory mathematically to investigate the reason for the nonlinear distribution of potential. By analyzing the electron transfer theory, we determined the condition and criterion for electron tunneling. We derived a formula for the relation between diffusion layer potential and electrode potential and compared it with the traditional model. The resulting curve exhibits a widened, sloped platform near the zero potential point. In addition, we analyzed the effects of the electrochemical double layer on input system signals using signal simulation. These results provide a foundation for further research in this area.
Antiferromagnetic fourfold anisotropy induced exchange bias and magnetization reversal behaviors in CoFeB/IrMn bilayers
Authors: Zhang Chenyu , Zhan Qingfeng , Hu Yong
Published: July 2023

Bilayers of an amorphous CoFeB ferromagnet coupled to an epitaxially grown IrMn antiferromagnet, whose anisotropy is fourfold symmetric, are modeled to study the angular (φ) dependence of magnetization reversal mechanism and exchange bias behavior, based on a modified Monte Carlo method. It is found that positive and negative exchange-bias field (HE) maximum values appear in the antiferromagnetic easy-axis directions, and the HE zero-value transition/return points exist in the antiferromagnetic hard-axis directions. Furthermore, the value of HE(φ) is well fitted by considering cos3φ/sin3φ terms with larger or comparable coefficients as compared to the first-order terms in the Fourier expansion. Finally, the microscopic spin configuration results evidence these phenomena originating from the tailoring of antiferromagnetic spins by simply rotating the field-cooling direction between antiferromagnetic easy- and hard-axis directions. We open an exchange-bias mode governed by antiferromagnetic fourfold anisotropy and propose a method to precisely detect antiferromagnetic higher-order anisotropies on an exchange-bias support.
Lipopolysaccharide-induced sepsis impairs M2R-GIRK signaling in the mouse sinoatrial node
Authors: Shrestha Niroj , Zorn-Pauly Klaus , Mesirca Pietro , Koyani Chintan N. , Wölkart Gerald , Di Biase Valentina , Torre Eleonora , Lang Petra , Gorischek Astrid , Schreibmayer Wolfgang , Arnold Robert , Maechler Heinrich , Mayer Bernd , von Lewinski Dirk , Torrente Angelo G. , Mangoni Matteo E. , Pelzmann Brigitte , Scheruebel Susanne
Published: July 2023

Sepsis has emerged as a global health burden associated with multiple organ dysfunction and 20% mortality rate in patients. Numerous clinical studies over the past two decades have correlated the disease severity and mortality in septic patients with impaired heart rate variability (HRV), as a consequence of impaired chronotropic response of sinoatrial node (SAN) pacemaker activity to vagal/parasympathetic stimulation. However, the molecular mechanism(s) downstream to parasympathetic inputs have not been investigated yet in sepsis, particularly in the SAN. Based on electrocardiography, fluorescence Ca
2+
imaging, electrophysiology, and protein assays from organ to subcellular level, we report that impaired muscarinic receptor subtype 2-G protein-activated inwardly-rectifying potassium channel (M2R-GIRK) signaling in a lipopolysaccharide-induced proxy septic mouse model plays a critical role in SAN pacemaking and HRV. The parasympathetic responses to a muscarinic agonist, namely
I
KACh
activation in SAN cells, reduction in Ca
2+
mobilization of SAN tissues, lowering of heart rate and increase in HRV, were profoundly attenuated upon lipopolysaccharide-induced sepsis. These functional alterations manifested as a direct consequence of reduced expression of key ion-channel components (GIRK1, GIRK4, and M2R) in the mouse SAN tissues and cells, which was further evident in the human right atrial appendages of septic patients and likely not mediated by the common proinflammatory cytokines elevated in sepsis.
EP300 facilitates human trophoblast stem cell differentiation
Authors: van Voorden A. Jantine , Keijser Remco , Veenboer Geertruda J. M. , Lopes Cardozo Solange A. , Diek Dina , Vlaardingerbroek Jennifer A. , van Dijk Marie , Ris-Stalpers Carrie , van Pelt Ans M. M. , Afink Gijs B.
Published: July 2023

Early placenta development involves cytotrophoblast differentiation into extravillous trophoblast (EVT) and syncytiotrophoblast (STB). Defective trophoblast development and function may result in severe pregnancy complications, including fetal growth restriction and pre-eclampsia. The incidence of these complications is increased in pregnancies of fetuses affected by Rubinstein–Taybi syndrome, a developmental disorder predominantly caused by heterozygous mutations in CREB-binding protein (
CREBBP
) or E1A-binding protein p300 (
EP300
). Although the acetyltransferases CREBBP and EP300 are paralogs with many overlapping functions, the increased incidence of pregnancy complications is specific for
EP300
mutations. We hypothesized that these complications have their origin in early placentation and that EP300 is involved in that process. Therefore, we investigated the role of EP300 and CREBBP in trophoblast differentiation, using human trophoblast stem cells (TSCs) and trophoblast organoids. We found that pharmacological CREBBP/EP300 inhibition blocks differentiation of TSCs into both EVT and STB lineages, and results in an expansion of TSC-like cells under differentiation-inducing conditions. Specific targeting by RNA interference or CRISPR/Cas9-mediated mutagenesis demonstrated that knockdown of
EP300
but not
CREBBP,
inhibits trophoblast differentiation, consistent with the complications seen in Rubinstein–Taybi syndrome pregnancies. By transcriptome sequencing, we identified transforming growth factor alpha (TGFA, encoding TGF-α) as being strongly upregulated upon
EP300
knockdown. Moreover, supplementing differentiation medium with TGF-α, which is a ligand for the epidermal growth factor receptor (EGFR), likewise affected trophoblast differentiation and resulted in increased TSC-like cell proliferation. These findings suggest that EP300 facilitates trophoblast differentiation by interfering with at least EGFR signaling, pointing towards a crucial role for EP300 in early human placentation.
Naturally mutagenic sequence diversity in a human type II topoisomerase
Authors: Bandak Afif F. , Blower Tim R. , Nitiss Karin C. , Gupta Raveena , Lau Albert Y. , Guha Ria , Nitiss John L. , Berger James M.
Published: July 2023

Type II topoisomerases transiently cleave duplex DNA as part of a strand passage mechanism that helps control chromosomal organization and superstructure. Aberrant DNA cleavage can result in genomic instability, and how topoisomerase activity is controlled to prevent unwanted breaks is poorly understood. Using a genetic screen, we identified mutations in the beta isoform of human topoisomerase II (hTOP2β) that render the enzyme hypersensitive to the chemotherapeutic agent etoposide. Several of these variants were unexpectedly found to display hypercleavage behavior in vitro and to be capable of inducing cell lethality in a DNA repair–deficient background; surprisingly, a subset of these mutations were also observed in
TOP2B
sequences from cancer genome databases. Using molecular dynamics simulations and computational network analyses, we found that many of the mutations obtained from the screen map to interfacial points between structurally coupled elements, and that dynamical modeling could be used to identify other damage-inducing
TOP2B
alleles present in cancer genome databases. This work establishes that there is an innate link between DNA cleavage predisposition and sensitivity to topoisomerase II poisons, and that certain sequence variants of human type II topoisomerases found in cancer cells can act as DNA-damaging agents. Our findings underscore the potential for hTOP2β to function as a clastogen capable of generating DNA damage that may promote or support cellular transformation.
Enhanced corrosion resistance of the as-cast AZ91 magnesium alloy by micro-addition of the strontium and rare earth elements
Authors: Afsharnaderi Aria , Lotfpour Mehrab , Bahmani Ahmad , Mirzadeh Hamed , Malekan Mehdi , Emamy Massoud , Fatehi Mollayousef Mojtaba , Bornay Zonoozi Soraya
Published: July 2023

The synergetic effect of strontium (Sr) and rare earth elements (RE) on the corrosion properties of as-cast Mg–9Al–1Zn alloy were studied. Via the addition of 0.5 wt-% RE and 0.5 wt-% Sr (RE/Sr ratio of 1), a remarkable reduction in the corrosion rate of AZ91 was observed. The reason was found to be related to the decrement of the micro-galvanic corrosion by the modification of the β-Mg17Al12 phase (changing its morphology from semi-continuous to a more spheroid shape) and formation of proper amounts of Al11RE3 and Al4Sr intermetallics. However, the excess RE/Sr ratio impaired the corrosion resistance, which can be related to the micro-galvanic effect by excess amounts of Al11RE3 and Al4Sr intermetallics.
Efficient cooling of high-angular-momentum atoms
Authors: Hillberry Logan E , Budker Dmitry , Rochester Simon M , Raizen Mark G
Published: July 2023

We propose a highly efficient and fast method of translational cooling for high-angular-momentum atoms. Optical pumping and stimulated transitions, combined with magnetic forces, can be used to compress phase-space density, and the efficiency of each compression step increases with the angular momentum. Entropy is removed by spontaneously emitted photons, and particle number is conserved. This method may be an attractive alternative to evaporative cooling of atoms and possibly molecules in order to produce quantum degenerate gases.
Band-structure based electrostatics model for ultra-thin-body double-gate silicon-on-insulator MOS devices
Authors: Mishra Nalin Vilochan , Kansal Harshit , Solanki Ravi , Medury Aditya Sankar
Published: July 2023

The effect of quantum confinement has become significant in terms of its impact on the scalability and electrostatics of ultra-thin-body double-gate MOSFETs. In this paper, we present a simplified model to account for the effect of quantum confinement, considering the contribution of the ground-state and the first excited state of the conduction band, on the electron carrier concentration, which when incorporated into the 1-D Poisson’s equation, enables the determination of the electrostatic potential. We establish the accuracy of the proposed model, over a wide range of process and electrical parameters, through aggressively benchmarking the electrostatics parameters obtained from the proposed model with results from the sp
3
d
5

s

∗

tight-binding method (TBM), over a wide range of device temperatures. Furthermore, a simplified model for the integrated channel charge density is shown in the form of a diffusion layer charge where the thickness and potential of this layer, while being gate voltage dependent, enables the channel charge density obtained from the model to agree well with results from TBM. Through this physics based and accurate model for the integrated charge, a simplified understanding of the gate capacitance is shown as a series combination of the diffusion layer capacitance, strong-inversion capacitance and oxide capacitance, which includes the effects of structural confinement as well as charge confinement at low and high gate voltages, respectively.
Gap electroacoustic waves in PT-symmetric piezoelectric heterostructure near the exceptional point
Authors: Vilkov E A , Byshevski-Konopko O A , Kalyabin D V , Nikitov S A
Published: July 2023

The spectral properties of gap electroacoustic waves in a PT-symmetric structure of piezoelectrics of symmetry class 6 mm separated by a gap are theoretically investigated. The spectra were calculated for lead germanate (non-zero transverse piezoactivity) and barium titanate (symmetry class 4 mm—zero transverse piezoactivity). It has been established that at a certain level of losses and gain in piezoelectrics, the symmetric and antisymmetric modes intersect. The intersection point determines the singular point of the PT-symmetric structure. Beyond this point, there is a violation of the symmetric and antisymmetric distribution of electric fields in the gap of the slotted structure of two identical piezoelectrics, which is confirmed by the calculation of the electric field profiles. It is shown that the dependence of the amplitude on the frequency at an exceptional point has an extremely narrow resonance peak, which opens up the possibility of creating supersensitive sensors based on PT-symmetric physical structures.
Adaptive scale chirplet transform and its application to bearing fault analysis
Authors: Hou Yating , Han Xingcheng , Bai Jiansheng , Wang Liming
Published: July 2023

In response to the problems of biased estimation of instantaneous frequency (If) and poor noise immunity in current time–frequency (Tf) analysis methods, the adaptive scale chirplet transform (ASCT) is proposed in this paper. The core idea of the proposed algorithm is to use a frequency-dependent quadratic polynomial kernel function to approximate the IF of the signal and to use the time-varying window length to overcome the frequency resolution problem due to the change in signal modulation. This method can dynamically select suitable parameters and overcome the disadvantage of unfocused energy of TF distribution. The experimental results show that the ASCT algorithm has high TF aggregation and can suppress noise interference well. In practical signal processing, the advantage of the ASCT algorithm is that it can accurately depict the characteristic frequency of the signal and detect the fault in the bearing signal. Both simulation and experimental results prove the strong realistic relevance of this algorithm.
Adaptive image enhancement and particle size identification method based on coal and gangue
Authors: Luo Qisheng , Wang Shuang , Guo Yongcun , He Lei , Li Xin
Published: July 2023

To reduce the influence of material particle size on coal gangue identification, a particle size identification method, and an adaptive image enhancement method are proposed, which can accurately identify the particle size of poorly segmented and mutually blocked materials, effectively reduce the reflection and blur of the image surface and enhance the texture details. Through the research of coal gangue images with different particle sizes, it is found that the image quality and feature curve distribution of small particle size are different from those of large particle size, and the gradient features are worse. In this paper, the accurate identification of particle size is realized using the difference in image quality and texture, and the identification rate is 99.25%. Through the image enhancement method in this paper, 33.41% of the reflection on the image surface is removed, and the average gradient is improved by 74.01%, which effectively improves the image quality and the ability to express texture information. This algorithm has high environmental adaptability, and the identification rate can reach 99.16% in moderate illumination, 98.33% in dim illumination, and 96.33% in strong illumination. This research provides a valuable idea for image processing and identification technology based on machine vision.
Nanostructural evolution of hydrothermally grown SrTiO3 perovskite and its implementation in gaseous phase detection of ethanol
Authors: Bhardwaj Radha , Jena Sushri Soumya , Srikar Valiveru Sai , Ghosh Sarbani , Hazra Arnab
Published: July 2023

A group of SrTiO3 nanostructures with unique nano-architecture have been synthesized in the current study. Sol–gel derived TiO2 nanoparticles along with Sr(OH)2 solution was processed with facial hydrothermal reaction at 180 °C and highly stable and distinct morphologies of SrTiO3 were developed after different reaction time. Nanobush, nanograss, nanorod and nanosphere morphologies were created after 10, 14, 18 and 24 h of hydrothermal reaction. SrTiO3 nanosphere was transformed into nano-hollow sphere morphology after thermal annealing at 600 °C. Detailed morphological, structural and chemical characterizations were carried out for all the distinct nanoforms of SrTiO3 where they exhibited high crystallinity, and chemical stability along with excellent surface properties like high porosity, roughness, and large effective surface area. Due to having rich surface properties, all the SrTiO3 morphologies were then implemented for gaseous phase detection of multiple volatile organic compounds (VOCs). However, all the SrTiO3 nanoforms showed ethanol selective behavior among all the VOCs. Nanograss and nano-hollow spheres exhibited excellent ethanol sensing with 69 and 78 response values (R
v/R
a) in 50 ppm ethanol at 150 °C with appreciably fast response/recovery times of 36 s/34 s and 150 s/ 58 s, respectively. Additionally, all the SrTiO3 nanostructures exhibited anti-humidity characteristics and potential sensing in humid ambient (up to 80% RH). Later, the ethanol selective behavior of SrTiO3 was established by density functional theory simulations which envisaged the highest negative adsorption energy and smallest distance (r) for ethanol molecule, implying stable adsorption with SrTiO3 (110) system.
Evaluation of mechanical properties of triple-junction-free polycrystalline graphene
Authors: Heo Jeonghyeon , Han Jihoon
Published: July 2023

Although chemical vapor deposition (CVD) has emerged as an important method for producing large-scale and relatively high-quality graphene, CVD-grown graphene inherently contains grain boundaries (GBs), which degrade its mechanical properties. To compensate for these characteristics, various studies have been conducted to maintain the mechanically superior properties by controlling the density of defects and GBs. In this study, the mechanical properties of triple junction (TJ)-free polycrystalline graphene, which is expected to exhibit excellent properties, were investigated through molecular dynamics simulations because TJ is well-known as a crack nucleation site due to stress concentration. We adopted the phase-field crystal method to model CVD-grown graphene-containing TJ-free polycrystalline materials. From a series of numerical simulations, we found that the fracture strength increases as the density of the GB increases. This trend is consistent with that presented in a previous experimental study measured by nanoindentation. It was determined that the variation in the fracture strength is related to the discontinuous density of 5–7 pairs, which act as stress-concentration sites. Additionally, we observed that the fracture strength was higher than that of polycrystalline graphene with TJ. We believe that these results have a higher mechanical advantage compared to the low strength of TJs shown in previous studies and will be important for future structural reliability-based graphene applications.
Magnetocardiography using optically pumped magnetometers array to detect acute myocardial infarction and premature ventricular contractions in dogs
Authors: Han Xiaole , Xue Xiaoyan , Yang Yanfei , Liang Xiaoyu , Gao Yang , Xiang Min , Sun Jinji , Ning Xiaolin
Published: July 2023

Objective. Optically pumped magnetometers (OPMs) are recently developed magnetocardiography (MCG) sensors that can detect cardiac diseases. This is of great clinical significance for detecting acute myocardial infarction (AMI) and premature ventricular contractions (PVC). This study investigates the use of an array of OPMs to detect heart disease in animals. Approach. An array of OPMs was used to detect the MCG of AMI and PVC in dogs. We used four dogs in this study, and models of AMI with different degrees of severity were established by ligating the middle and proximal segments of the left anterior descending coronary artery. The dogs had PVC at the time of AMI. Continuous MCG time series with corresponding electrocardiograms (ECGs) and average MCG for each dog in different states are presented. The MCG features were extracted from the MCG butterfly diagram, magnetic field map, and pseudo current density map. The MCG features were used to quantify and compare with the gold-standard ECG measures. Main results. The results show that MCG features can accurately distinguish different states of dogs. That is, an array of OPMs can effectively detect AMI and PVC in dogs. Significance. We conclude that the array of OPMs can detect heart diseases in animals. Moreover, OPMs can complement or even replace superconducting quantum interference devices for MCG measurement in animals and diagnosis of human heart diseases in the future.
Commissioning dose computation model for proton source in pencil beam scanning therapy by convolution neural networks
Authors: Liu Yaoying , Shang Xuying , Zhao Wei , Li Nan , Qu Baolin , Zou Yue , Le Xiaoyun , Zhang Gaolong , Xu Shouping
Published: July 2023

Objective. Proton source model commissioning (PSMC) is critical for ensuring accurate dose calculation in pencil beam scanning (PBS) proton therapy using Monte Carlo (MC) simulations. PSMC aims to match the calculated dose to the delivered dose. However, commissioning the ‘nominal energy’ and ‘energy spread’ parameters in PSMC can be challenging, as these parameters cannot be directly obtained from solving equations. To efficiently and accurately commission the nominal energy and energy spread in a proton source model, we developed a convolution neural network (CNN) named ‘PSMC-Net.’ Methods. The PSMC-Net was trained separately for 33 energies (E, 70–225 MeV with a step of 5 MeV plus 226.09 MeV). For each E, a dataset was generated consisting of 150 source model parameters (15 nominal energies ∈ [E, E + 1.5 MeV], ten spreads ∈ [0, 1]) and the corresponding 150 MC integrated depth doses (IDDs). Of these 150 data pairs, 130 were used for training the network, 10 for validation, and 10 for testing. Results. The source model, built by 33 measured IDDs and 33 PSMC-Nets (cost 0.01 s), was used to compute the MC IDDs. The gamma passing rate (GPRs, 1 mm/1%) between MC and measured IDDs was 99.91 ± 0.12%. However, when no commissioning was made, the corresponding GPR was reduced to 54.11 ± 22.36%, highlighting the tremendous significance of our CNN commissioning method. Furthermore, the MC doses of a spread-out Bragg peak and 20 patient PBS plans were also calculated, and average 3D GPRs (2 mm/2% with a 10% threshold) were 99.89% and 99.96 ± 0.06%, respectively. Significance. We proposed a nova commissioning method of the proton source model using CNNs, which made the PSMC process easy, efficient, and accurate.