bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron doping of SmNiO3 via interfacial charge transfer: A first-principles study
Authors: Weng Yakui , Long Fei , Chen Yinan , Miao Fengyu , Li Jie , Cheng Jie , Li Xing’ao
Published: June 2023

SmNiO3 is a representative quantum material exhibiting the antidoping behavior, where the conductivity of the material is reduced rather than increased by electron doping. Recent experimental and theoretical works have demonstrated a phase transition of SmNiO3 with large conductance changes via chemical methods. However, the effect of electron doping via interfacial charge transfer in SmNiO3 is much less studied. In this work, the first-principles density functional theory (DFT)+U method is employed to investigate the SmNiO3/YTiO3 superlattice, in which the YTiO3 layer acts as the electron donor. Compared with the chemical doping in SmNiO3, several interesting physical phenomena have been predicted in SmNiO3/YTiO3 superlattices due to the lattice and electronic reconstructions. First, at a doping concentration of 1e− per Ni, i.e., (SmNiO3)1/(YTiO3)1 superlattice, all Ni3+ are converted to Ni2+, resulting in a Mott-insulating phase, similar to the chemical doping in the pristine material. Interestingly, such a Mott gap can be efficiently modulated by tuning the stacking orientation. Second, at a doping concentration of 12e− per Ni, i.e., [001]-orientated (SmNiO3)2/(YTiO3)1 superlattice, the electronic structure associated with charge ordering depends on the concrete magnetic order, giving rise to magnetism-dependent electronic behavior. In addition, as the doping concentration further decreases (i.e., a doping concentration of 13e−/Ni), a metallic state is predicted in a [001]-orientated (SmNiO3)3/(YTiO3)1 superlattice, which is quite different from the case of chemical doping.
Control of mush complex viscosity on mid-ocean ridge topography: A fluid–structure model analysis
Authors: Sen Joyjeet , Sarkar Shamik , Mandal Nibir
Published: June 2023

This article exploits the interaction dynamics of the elastic oceanic crust with the underlying mush complexes (MC) to constrain the axial topography of mid-ocean ridges (MORs). The effective viscosity (μeff) of MC beneath MORs is recognized as the crucial factor in modulating their axial high vs flat topography. Based on a two-step viscosity calculation (suspension and solid-melt mixture rheology), we provide a theoretical estimate of μeff as a function of melt suspension characteristics (crystal content, polymodality, polydispersity, and strain rate) and its volume fraction in the MC region. We then develop a numerical model to show the control of μeff on the axial topography. Using an enthalpy-porosity-based fluid formulation of uppermost mantle, the model implements a one-way fluid–structure interaction that transmits viscous forces of the MC region to the overlying upper crust. The limiting non-rifted topographic elevations (−0.06–1.27 km) of model MORs are found to occur in the viscosity range of μeff = 1012–1014 Pa s. The higher end (1013–1014) Pa s of this spectrum produces axial highs, which are replaced by flat or slightly negative topography as μeff≤5×1012 Pa s. We discuss a number of major natural MORs to validate the model findings.
Analysis of plasma-elastic component of time-domain photoacoustic response
Authors: Stanimirović Ivanka , Markushev Dragana , Stanimirović Zdravko , Galović Slobodanka , Djordjević Katarina
Published: June 2023

The plasma-elastic component of the photoacoustic response in the time-domain of thin semiconductor samples excited by long electromagnetic radiation pulses is analyzed in detail. The plasma-elastic component model assumes that ambipolar diffusion can be approximated by the minority carrier diffusion. The results obtained show that the plasma-elastic component in thin semiconductor samples affects photoacoustic measurements in the time domain, which is important for the photoacoustic determination of semiconductor electronic properties.
Ice breakloose friction
Authors: Persson B. N. J. , Tyrode E. C.
Published: June 2023

We discuss the origin of the breakloose (or static) friction force when an ice block is slid on a hard randomly rough substrate surface. If the substrate has roughness with small enough amplitude (of order a 1 nm or less), the breakloose force may be due to interfacial slip and is determined by the elastic energy per unit area, Uel/A0, stored at the interface after the block has been displaced a short distance from its original position. The theory assumes complete contact between the solids at the interface and that there is no elastic deformation energy at the interface in the original state before the application of the tangential force. The breakloose force depends on the surface roughness power spectrum of the substrate and is found to be in good agreement with experimental observations. We show that as the temperature decreases, there is a transition from interfacial sliding (mode II crack propagation, where the crack propagation energy GII = Uel/A0) to opening crack propagation (mode I crack propagation with GI the energy per unit area to break the ice–substrate bonds in the normal direction).
Modulation of electromagnetic waves in a relativistic degenerate plasma at finite temperature
Authors: Roy Sima , Misra A. P. , Abdikian A.
Published: June 2023

We study the modulational instability (MI) of a linearly polarized electromagnetic (EM) wave envelope in an intermediate regime of relativistic degenerate plasmas at a finite temperature (T≠0) where the thermal energy (KBT) and the rest-mass energy (mec2) of electrons do not differ significantly, i.e., βe≡KBT/mec2≲ (or ≳) 1, but the Fermi energy (KBTF) and the chemical potential energy (μe) of electrons are still a bit higher than the thermal energy, i.e., TF>T and ξe=μe/KBT≳1. Starting from a set of relativistic fluid equations for degenerate electrons at finite temperature, coupled to the EM wave equation and using the multiple scale perturbation expansion scheme, a one-dimensional nonlinear Schödinger (NLS) equation is derived, which describes the evolution of slowly varying amplitudes of EM wave envelopes. Then, we study the MI of the latter in two different regimes, namely, βe<1 and βe>1. Like unmagnetized classical cold plasmas, the modulated EM envelope is always unstable in the region βe>4. However, for βe≲1 and 1<βe<4, the wave can be stable or unstable depending on the values of the EM wave frequency, ω, and the parameter ξe. We also obtain the instability growth rate for the modulated wave and find a significant reduction by increasing the values of either βe or ξe. Finally, we present the profiles of the traveling EM waves in the form of bright (envelope pulses) and dark (voids) solitons, as well as the profiles (other than traveling waves) of the Kuznetsov–Ma breather, the Akhmediev breather, and the Peregrine solitons as EM rogue (freak) waves, and discuss their characteristics in the regimes of βe≲1 and βe>1.
Robust formulation of Wick’s theorem for computing matrix elements between Hartree–Fock–Bogoliubov wavefunctions
Authors: Chen Guo P. , Scuseria Gustavo E.
Published: June 2023

Numerical difficulties associated with computing matrix elements of operators between Hartree–Fock–Bogoliubov (HFB) wavefunctions have plagued the development of HFB-based many-body theories for decades. The problem arises from divisions by zero in the standard formulation of the nonorthogonal Wick’s theorem in the limit of vanishing HFB overlap. In this Communication, we present a robust formulation of Wick’s theorem that stays well-behaved regardless of whether the HFB states are orthogonal or not. This new formulation ensures cancellation between the zeros of the overlap and the poles of the Pfaffian, which appears naturally in fermionic systems. Our formula explicitly eliminates self-interaction, which otherwise causes additional numerical challenges. A computationally efficient version of our formalism enables robust symmetry-projected HFB calculations with the same computational cost as mean-field theories. Moreover, we avoid potentially diverging normalization factors by introducing a robust normalization procedure. The resulting formalism treats even and odd number of particles on equal footing and reduces to Hartree–Fock as a natural limit. As proof of concept, we present a numerically stable and accurate solution to a Jordan–Wigner-transformed Hamiltonian, whose singularities motivated the present work. Our robust formulation of Wick’s theorem is a most promising development for methods using quasiparticle vacuum states.
Effect of tannins and kafirins on the nitrogen and energy balance and performance of pigs
Authors: Reis De Souza Tércia Cesária , Ávila Árres Iris Elisa , Gómez-Soto José Guadalupe , Escobar García Konisgmar , Ramírez Rodríguez Ericka , Mariscal-Landín Gerardo
Published: June 2023

Context Tannins are blamed for negatively affecting nutritive value of sorghum. Kafirins are sorghum storage proteins and may be associated with lower animal performance. They have been tested in poultry diets; however, information for pig diets is scarce. Aims Our aim was to determine the role of kafirins and tannins in sorghum nutritive value for swine. Methods Two experiments evaluated effects of sorghum tannin and kafirin levels on (1) nitrogen (N) and energy balance, and (2) performance of pigs. Two sorghum hybrids with low (LT) and high (HT) tannins were grown at two rates of N fertiliser to achieve low (LK) and high (HK) kafirins (i.e. four sorghum treatments: LTLK, LTHK, HTLK and HTHK) and added to soybean meal based diets. A fifth diet included maize instead of sorghum. Five pigs (48.8 ± 0.4 kg) were used in a 5 × 5 Latin square design to measure N and energy balance, with 5 days of diet adaptation and 4 days of urine and faeces collection. The performance experiment included 60 pigs (54.0 ± 12.4 kg, 30 barrows and 30 gilts, six of each per treatment) placed in individual pens with free access to water and feed. Key results Energy balance showed a tannin × kafirin interaction (P < 0.05) for dry matter feed intake, which diminished with the LTHK diet and was unaffected with the HTHK diet. Dry matter digestibility was higher (P < 0.001) with maize, intermediate with LT, and lower with HT diets. Pigs fed maize retained more N (P < 0.05) and had higher energy digestibility (P < 0.001) than pigs fed sorghum. HT diets had lower (P < 0.01) energy digestibility than LT diets. In the finishing phase, average daily feed intake showed a tannin × kafirin interaction (P < 0.05); pigs fed the HTHK diet had lower average daily feed intake than other pigs. This lowered average daily liveweight gain and consequently final weight. Conclusions Tannins negatively affected sorghum nutritive value; high kafirins worsened average daily feed intake and liveweight gain, and hence final weight. Implications Management of kafirin content should be considered to avoid adverse performance effects in pigs fed sorghum.
How temperature, substrate, and stratification periods influence Ilex paraguariensis embryonic development
Authors: Duarte Manoela Mendes , Walter Letícia Siqueira , Gabira Mônica Moreno , Porath Cléberson , Vieira Elisa Serra Negra , Nogueira Antonio Carlos , Wendling Ivar , Kratz Dagma
Published: June 2023

Aiming to develop a new stratification protocol for yerba mate seeds, we evaluated how different combinations of temperature, substrate, and period influence the embryonic development of the species, compared to fresh seeds and conventionally stratified seeds. We measured the seeds’ moisture content and performed a tetrazolium test to evaluate embryo viability and embryonic development. Seeds’ initial moisture content was 10.1% and reached 40.6% after stratification. We observed more embryos in advanced development stages after stratification in all treatments, indicating that the protocols used were adequate for the species and have a great potential to be explored for yerba mate seedling.
Agronomic soil tests can be used to estimate dissolved reactive phosphorus loss
Authors: Weaver David , Summers Robert , Neuhaus Andreas
Published: June 2023

Context Phosphorus (P) use in agriculture can lead to eutrophication. Agronomic soil tests such as Colwell P and P buffering index (PBI) define critical soil P levels for pasture production. These tests have potential for re-use as environmental risk indicators of dissolved reactive P (DRP) loss from paddocks but are constrained because a 0–10 cm sample does not necessarily align with the dominant hydrological loss pathways of runoff or leaching. Aims To identify influences on the benchmark environmental measure of DRP (CaCl2-extractable P or CaCl2-P) by agronomic-based measures such as PBI, Colwell P and depth, and Colwell P to PBI ratio (P environmental risk index; PERI). To estimate CaCl2-P at any depth from a 0–10 cm sample, and the potential for change in DRP loss risk through the adoption of evidence-based fertiliser management based on soil testing. Methods Archives of 692 0–10-cm soil samples, along with 88 sites sampled at 0–10 cm and 0–1, 1–2, 2–5, 5–10, 10–20, and 20–30 cm were analysed for Colwell P, PBI, CaCl2-P, PERI, and P fertility index (PFI). Derived relationships between CaCl2-P and Colwell P for different PBI were applied to 30 981 0–10-cm samples to estimate the potential for DRP reduction resulting from the adoption of evidence-based fertiliser management. Key results CaCl2-P, Colwell P, PERI, and PFI decreased with depth, with an associated increase in DRP loss risk from surface soil. The CaCl2-P decreased with increasing PBI. The CaCl2-P, Colwell P, PERI, and PFI could be estimated at any depth from a 0–10 cm sample, with r2 > 0.77. The CaCl2-P was estimable from PERI, and soils with low PBI or with high PFI had high DRP loss risk. The CaCl2-P was positively correlated with Colwell P, with the slope decreasing with increasing PBI and becoming invariant when PBI > 100. When applied to the current soil Colwell P and estimated current CaCl2-P and compared to CaCl2-P at the critical Colwell P for different relative yields (RYs), DRP loss risk could be reduced by 24% for a RY target of 95%, and 59% for a RY target of 80%. Conclusions Because current Colwell P levels in soils exceed critical values, DRP loss risk can be substantially reduced by adopting evidence-based fertiliser management with little or no loss of utilised pasture. Implications Fertiliser management based on evidence of P requirements determined from soil testing has a significant role in reducing DRP loss risk.
Membrane shapers from two distinct superfamilies cooperate in the development of neuronal morphology
Authors: Izadi Maryam , Wolf David , Seemann Eric , Ori Alessandro , Schwintzer Lukas , Steiniger Frank , Kessels Michael Manfred , Qualmann Britta
Published: June 2023

Membrane-shaping proteins are driving forces behind establishment of proper cell morphology and function. Yet, their reported structural and in vitro properties are noticeably inconsistent with many physiological membrane topology requirements. We demonstrate that dendritic arborization of neurons is powered by physically coordinated shaping mechanisms elicited by members of two distinct classes of membrane shapers: the F-BAR protein syndapin I and the N-Ank superfamily protein ankycorbin. Strikingly, membrane-tubulating activities by syndapin I, which would be detrimental during dendritic branching, were suppressed by ankycorbin. Ankycorbin’s integration into syndapin I–decorated membrane surfaces instead promoted curvatures and topologies reflecting those observed physiologically. In line with the functional importance of this mechanism, ankycorbin- and syndapin I–mediated functions in dendritic arborization mutually depend on each other and on a surprisingly specific interface mediating complex formation of the two membrane shapers. These striking results uncovered cooperative and interdependent functions of members of two fundamentally different membrane shaper superfamilies as a previously unknown, pivotal principle in neuronal shape development.
RTN3 and RTN4: Architects of SARS-CoV-2 replication organelles
Authors: Kratzel Annika , Thiel Volker
Published: June 2023

SARS-CoV-2 depends on host proteins for successful replication. In this issue, Williams et al. (2023. J. Cell Biol.https://doi.org/10.1083/jcb.202203060) report that the ER membrane-modulating proteins RTN3 and RTN4 are required for the formation of SARS-CoV-2 replication organelles via direct interaction with viral proteins NSP3 and NSP4.
Interactions between selectivity filter and pore helix control filter gating in the MthK channel
Authors: Kopec Wojciech , Thomson Andrew S. , de Groot Bert L. , Rothberg Brad S.
Published: June 2023

K+ channel activity can be limited by C-type inactivation, which is likely initiated in part by dissociation of K+ ions from the selectivity filter and modulated by the side chains that surround it. While crystallographic and computational studies have linked inactivation to a “collapsed” selectivity filter conformation in the KcsA channel, the structural basis for selectivity filter gating in other K+ channels is less clear. Here, we combined electrophysiological recordings with molecular dynamics simulations, to study selectivity filter gating in the model potassium channel MthK and its V55E mutant (analogous to KcsA E71) in the pore-helix. We found that MthK V55E has a lower open probability than the WT channel, due to decreased stability of the open state, as well as a lower unitary conductance. Simulations account for both of these variables on the atomistic scale, showing that ion permeation in V55E is altered by two distinct orientations of the E55 side chain. In the “vertical” orientation, in which E55 forms a hydrogen bond with D64 (as in KcsA WT channels), the filter displays reduced conductance compared to MthK WT. In contrast, in the “horizontal” orientation, K+ conductance is closer to that of MthK WT; although selectivity filter stability is lowered, resulting in more frequent inactivation. Surprisingly, inactivation in MthK WT and V55E is associated with a widening of the selectivity filter, unlike what is observed for KcsA and reminisces recent structures of inactivated channels, suggesting a conserved inactivation pathway across the potassium channel family.
Large valley polarization and high Curie temperature in single layer XI2 (X = Sc, Y)
Authors: Lan Mengxian , Li Ying , Qiao Shiqian , Huang Tian , Ma Sai , Ding Feng , Wu Hong , Li Feng , Pu Yong
Published: June 2023

Ferrovalley materials with spontaneous valley polarization are the key to valleytronics applications. Therefore, it is important to find materials with relatively large valley polarization. In this work, we theoretically designed two novel two-dimensional ferrovalley materials namely XI2 (X = Sc, Y), which have both high Curie temperature and large valley polarization. The Curie temperature of monolayer ScI2 and YI2 are 138 K and 58 K, the large valley polarization of 97 meV and 108 meV are also predicted in monolayer ScI2 and YI2. The anomalous valley Hall effect is also proposed based on the valley contrasting Berry curvature. In addition, strain engineering can effectively modulate the valley polarization and Curie temperature of monolayer XI2 (X = Sc, Y). The Curie temperature of ScI2 increases with increasing strain, and the valley polarization of YI2 increases with increasing strain. Our findings suggest that monolayer XI2 (X = Sc, Y) is a promising material for valleytronics.
Structural and mechanical properties of NiTiAg shape memory alloys: ab-initio study
Authors: Priyanga G Sudha , Santosh S , Mattur Manoj N
Published: June 2023

The austenite phase of Ni50−x
Ti50Ag
x
for different concentrations (x = 1, 1.5, 2, 3, 5, 7, 8, 10) has been analyzed in this work. The ground state, structural, and mechanical characteristics of Ni50−x
Ti50Ag
x
for various concentrations are examined under ambient conditions. From total energy as well as formation energy calculations, it is found that the stability of Ni50−x
Ti50Ag
x
austenite phase is increased up to x = 5 and after that it becomes unstable in nature. These results are in good agreement with our experimental results. The experimental and other theoretical results agree with the estimated lattice parameter values. The x-ray diffraction and differential scanning calorimetry reveal the phases formed and transformation characteristics of NiTiAg alloys. The elastic constants, bulk modulus, shear modulus, Poisson’s ratio, and elastic anisotropy factor of Ni50−x
Ti50Ag
x
are examined at ambient conditions for different concentrations. From elastic constant calculations, it is also found that the austenite phase of Ni50−x
Ti50Ag
x
is mechanically stable up to x = 5 and after that it does not obey Born–Huang criteria and becomes unstable. The Ni45Ti50Ag5 composition is found to be the stiffest and hardest material. According to Poisson’s ratio calculations, Ni50−x
Ti50Ag
x
shows that the Ti–Ag, Ni–Ag bonding is more directed in nature. The austenite phase of Ni50−x
Ti50Ag
x
is more incompressible because the Poisson’s ratio is nearly equal to the optimum value (0.5).
Fully-integrated photonic tensor core for image convolutions
Authors: Marquez Bicky A , Singh Jagmeet , Morison Hugh , Guo Zhimu , Chrostowski Lukas , Shekhar Sudip , Prucnal Paul , Shastri Bhavin J
Published: June 2023

Convolutions are one of the most critical signal and image processing operations. From spectral analysis to computer vision, convolutional filtering is often related to spatial information processing involving neighbourhood operations. As convolution operations are based around the product of two functions, vectors or matrices, dot products play a key role in the performance of such operations; for example, advanced image processing techniques require fast, dense matrix multiplications that typically take more than 90% of the computational capacity dedicated to solving convolutional neural networks. Silicon photonics has been demonstrated to be an ideal candidate to accelerate information processing involving parallel matrix multiplications. In this work, we experimentally demonstrate a multiwavelength approach with fully integrated modulators, tunable filters as microring resonator weight banks, and a balanced detector to perform matrix multiplications for image convolution operations. We develop a scattering matrix model that matches the experiment to simulate large-scale versions of these photonic systems with which we predict performance and physical constraints, including inter-channel cross-talk and bit resolution.
Boundedness in a logistic chemotaxis system with weakly singular sensitivity in dimension two
Authors: Zhao Xiangdong
Published: June 2023

This paper deals with the parabolic-elliptic Keller–Segel system with weakly singular sensitivity and logistic source under the homogeneous Neumann boundary:

u
t

=
Δ
u
−
χ
∇
⋅
(

u

v
α

∇
v
)
+
r
u
−
μ

u
2

,

0
=
Δ
v
−
v
+
u

in a smooth bounded domain

Ω
⊂

R

2

, with

χ
,
α
,
μ
>
0

,

r
∈

R

. It is proved that the system possesses a globally bounded classical solution for

α
∈
(
0
,
1
)

with µ > 0 suitably large, without establishing the uniformly positive bound for v from below. In addition, we give the explicit expression of the upper bound for solution u with respect to the parameters

χ
,
α
,
r
,
μ

via a recursive argument on α. This concludes that weakly singular sensitivity benefits to obtain the global boundedness of classical solution in dimension two.
HyperTDP-Net: A Hyper-densely Connected Compression-and-Decomposition Network Based on Trident Dilated Perception for PET and MRI Image Fusion
Authors: Li Bicao , Du Yifan , Wang Bei , Shao Zhuhong , Huang Jie , Wei Miaomiao , Lu Jiaxi
Published: June 2023

Objective. Since medical images generated by medical devices have low spatial resolution and quality, fusion approaches on medical images can generate a fused image containing a more comprehensive range of different modal features to help physicians accurately diagnose diseases. Conventional methods based on deep learning for medical image fusion usually extract only local features without considering their global features, which often leads to the problem of unclear detail information in the final fused image. Therefore, medical image fusion is a challenging task of great relevance. Approach. This paper proposes a novel end-to-end medical image fusion model for PET and MRI images to achieve information interaction between different pathways, termed as hyper-densely connected compression-and-decomposition network based on trident dilated perception for PET and MRI image fusion (HyperTDP-Net). In particular, in the compression network, a dual residual hyper densely module is constructed to take full advantage of middle layer information. Moreover, we establish the trident dilated perception module to precisely determine the location information of features, and improve the feature representation capability of the network. In addition, we abandon the ordinary mean square error as the content loss function and propose a new content-aware loss consisting of structural similarity loss and gradient loss, so that the fused image not only contains rich texture details but also maintains sufficient structural similarity with the source images.Main results. The experimental dataset used in this paper is derived from multimodal medical images published by Harvard Medical School. Extensive experiments illustrate that our model contains more edge information and texture detail information in the fusion result than the 12 state-of-the-art fusion models and ablation study results demonstrate the effectiveness of three technical innovations.Significance. As medical images continue to be used in clinical diagnosis, our method is expected to be a tool that can effectively improve the accuracy of physician diagnosis and automatic machine detection.
Virtual 4DCT generated from 4DMRI in gated particle therapy: phantom validation and application to lung cancer patients
Authors: Annunziata S , Rabe M , Vai A , Molinelli S , Nakas A , Meschini G , Pella A , Vitolo V , Barcellini A , Imparato S , Ciocca M , Orlandi E , Landry G , Kamp F , Kurz C , Baroni G , Riboldi M , Paganelli C
Published: June 2023

Objective. Respiration negatively affects the outcome of a radiation therapy treatment, with potentially severe effects especially in particle therapy (PT). If compensation strategies are not applied, accuracy cannot be achieved. To support the clinical practice based on 4D computed tomography (CT), 4D magnetic resonance imaging (MRI) acquisitions can be exploited. The purpose of this study was to validate a method for virtual 4DCT generation from 4DMRI data for lung cancers on a porcine lung phantom, and to apply it to lung cancer patients in PT. Approach. Deformable image registration was used to register each respiratory phase of the 4DMRI to a reference phase. Then, a static 3DCT was registered to this reference MR image set, and the virtual 4DCT was generated by warping the registered CT according to previously obtained deformation fields. The method was validated on a physical phantom for which a ground truth 4DCT was available and tested on lung tumor patients, treated with gated PT at end-exhale, by comparing the virtual 4DCT with a re-evaluation 4DCT. The geometric and dosimetric evaluation was performed for both proton and carbon ion treatment plans. Main results. The phantom validation exhibited a geometrical accuracy within the maximum resolution of the MRI and mean dose deviations, with respect to the prescription dose, up to 3.2% for target D
95%, with a mean gamma pass rate of 98%. For patients, the virtual and re-evaluation 4DCTs showed good correspondence, with errors on target D
95% up to 2% within the gating window. For one patient, dose variations up to 10% at end-exhale were observed due to relevant inter-fraction anatomo-pathological changes that occurred between the planning and re-evaluation CTs. Significance. Results obtained on phantom data showed that the virtual 4DCT method was accurate, allowing its application on patient data for testing within a clinical scenario.
Theory of Josephson current on a lattice model of grain boundary in d-wave superconductors
Authors: Sakamori Takashi , Kashiwaya Satoshi , Yano Rikizo , Tanaka Yukio , Hatano Takafumi , Yada Keiji
Published: June 2023

Identifying the origins of suppression of the critical current at grain boundaries of high-critical-temperature superconductors, such as cuprates and iron-based superconductors, is a crucial issue to be solved for future applications with polycrystalline materials. Although the dominant factor of current suppression might arise during material fabrication and/or processing, investigating it due to an internal phase change of the pair potential is an important issue in understanding the threshold of the critical current. In this paper, we study the Josephson current on a symmetric [001]-tilt grain boundary (GB) of a d-wave superconductor on a lattice model. In addition to the suppression of the maximum Josephson current associated with the internal phase change of the d-wave pair potential which has been predicted in continuum models, we find a unique phase interference effect due to folding of the Fermi surface in the lattice model. In particular, the resultant maximum Josephson current at low-tilting-angle regions tends to be suppressed more than that in preexisting theories. Because similar suppressions of the critical current at GBs have been reported in several experimental works, the present model can serve as a guide to clarify the complicated transport mechanism in GBs.
Memristive chaotic system-based hybrid image encryption application with AES and RSA algorithms
Authors: Sahin M Emin
Published: June 2023

The widespread use of information and communication tools today facilitates information access and highlights the significance of information and data security. In recent years, chaos-based encryption systems have emerged as a promising approach for protecting the confidentiality of transmitted images. In particular, memristor-based hyperchaotic systems have attracted significant attention because of their robustness and complexity. In this paper, we propose an image encryption model that employs a two-stage encryption method using various chaotic systems, including the logistic map, Lorenz chaotic system, and memristor-based hyperchaotic system, with AES and RSA encryption algorithms. The proposed hybrid scheme applies bit-based pixel diffusion and confusion techniques to improve the security of encrypted images. Statistical and security tests are conducted to compare the performance of the different encryption systems and algorithms and to present the measurement values obtained from the analysis. Our experimental results demonstrate the effectiveness of the proposed image encryption scheme in terms of security, speed, and reliability and provide valuable insights for the development of future chaos-based encryption systems.
Solitons, breathers and periodic rogue waves for the variable-coefficient seventh-order nonlinear Schrödinger equation
Authors: Jiang Dongzhu , Zhaqilao
Published: June 2023

Through Darboux transformation (DT) method, Several nonlinear wave solutions of seventh-order variable-coefficient nonlinear Schrödinger (vcNLS) equation are obtained, including solitons, breathers and rogue periodic waves. When the coefficients are linear, parabolic and periodic functions, the parabolic, cubic and quasi-periodic solitons and breathers can be constructed. Then we investigate their effects on the solutions, the variation of the coefficients affects the shape of the solutions. On this basis, the interactions between two solitons are studied and the interactions between two types of breathers are constructed. Next, through the approaches of the nonlinearization of spectral problem and DT method, rogue waves on the background of the Jacobi elliptic functions dn and cn for a seventh-order vcNLS equation are constructed. When the coefficients are selected as linear, exponential and periodic functions, the nonlinear dynamics of two kinds of rogue periodic waves are analysed.
Asymmetric dark matter abundance including non-thermal production
Authors: Qingshan Ma , Iminniyaz Hoernisa
Published: June 2023

We investigate the relic abundance of asymmetric dark matter where the asymmetric dark matter is non–thermally produced from the decay of heavier particles in addition to the usual thermal production. We discuss the relic density of asymmetric dark matter including the decay of heavy particles in low-temperature scenarios. Here, we still assume that the Universe is radiation-dominated and there is asymmetry before the decay of heavy particles. We obtain an increased abundance of asymmetric dark matter when there is an additional contribution from the decay of heavier particles. Finally, we find the constraints on the asymmetry factor and annihilation cross-section using Planck data.
Small intestine submucosa as a growth factor attractor promotes peripheral nerve regeneration by enhancing syndecan-3/glial cell line-derived neurotrophic factor (GDNF) signalling: in vivo study
*
Authors: Liu Chiung-Hui , Chu Yin-Hung , Chen Yin Hsiu , Chiang Yu Hsin , Chen Yu Hsuan , Ku Chung Yao , Hsu Min-Yen , Lee Yi-Ju , Yang Mao-Yi , Liao Wen-Chieh
Published: June 2023

Peripheral nerve regeneration (PNR) following trauma requires the reconstruction of the extracellular matrix (ECM) and the proper stimulation of growth factors. Decellularised small intestine submucosa (SIS) has been extensively used as an ECM scaffold for tissue repair, but its potential to enhance the effects of exogenous growth factors on PNR is not well understood. In this study, we evaluated the effects of SIS implantation combined with glial cell-derived growth factor (GDNF) treatment on PNR in a rat neurorrhaphy model. We found that both SIS and regenerating nerve tissue expressed syndecan-3 (SDC3), one of major heparan sulphate proteoglycans in nerve tissue, and that SDC3 interacted with GDNF in the regenerating nerve tissue. Importantly, the SIS-GDNF combined treatment enhanced the recovery of neuromuscular function and β3-tubulin-positive axonal outgrowth, indicating an increase in the number of functioning motor axons connecting to the muscle after neurorrhaphy. Our findings suggest that the SIS membrane offers a new microenvironment for neural tissue and promotes neural regeneration based on SDC3-GDNF signalling, providing a potential therapeutic approach for PNR.
Roles of chemistry modification for surface wettability of Polyether-Ether-Ketone (PEEK) by ultraviolet laser ablation
Authors: Xu Peiyun , Zhu Fengjin , Wang Xiaohui , Zhang Junjie , Sun Tao
Published: June 2023

Tailoring the functionality of Polyether-ether-ketone (PEEK) is critical for enhancing its application, which can be accomplished by the modification of surface morphology and chemistry. In the present work, we experimentally demonstrate the correlation of modified chemical composition of textured PEEK surface by 355 nm UV nanosecond pulsed laser ablation with enhanced surface wettability. Specifically, the impact of UV laser processing parameters on microgroove morphology and ablated surface quality of PEEK surface is evaluated, with which high precision grid surface textures with uniform ablation quality are fabricated. The modification of chemical elements and functional groups of textured PEEK surface by the laser ablation is further analyzed by XPS spectra characterization, which demonstrates the substantial change of C=O and O–C=O bonds, as well as freshly generated polar carboxylic acid groups. Experimental results indicate that the surface composition modification greatly increases surface polarity and surface free energy of textured PEEK surface accompanied by enhanced surface wettability.
A novel approach for recycling agricultural wastes in the synthesis of nanomaterials and their composites
Authors: Jeet Kiran , Kaur Ramandeep
Published: June 2023

In this study, main focus has been drawn on the utilization of agricultural waste sources to synthesize nanomaterials. Graphene oxide and nanocellulose were prepared using rice husk ash and sugarcane bagasse, respectively. Further, their nanocomposites were also prepared in (1:1) ratio of graphene oxide and nanocellulose. The synthesized nanomaterials from agricultural waste were compared with those prepared from conventional sources through varied characterizations. Scanning electron microscopy, transmission electron microscopy, fourier transform infrared spectroscopy and N2 adsorption-desorption analysis was performed to examine the structural, functional and surface properties of the prepared nanomaterials from different precursors. High resolution imaging revealed better structural characteristics of the nanomaterials fabricated from agri-waste precursors. SEM images showed well exfoliated structure of GO and porous nature of NC. The folded layers of GO represent the presence of hydroxyl groups in the TEM images of GO @ graphite powder. TEM images of nanocellulose showed circular shaped nanoparticles of NC @ cellulose powder. Fourier transform infrared spectroscopy confirmed the presence of all the essential functional groups in the structure of prepared nanomaterials. The nanocomposites prepared using agricultural waste sources and conventional sources were inspected by N2 adsorption-desorption analysis, which demonstrated that the nanocomposites prepared from agri-waste sources exhibits much higher specific surface area than that of prepared from conventional precursors. R2 possess specific surface area of 82.832 m2 g−1 while, R1 possess only 6.721 m2 g−1. N2 adsorption-desorption analysis revealed the pore volume, pore diameter, micropore volume, micropore area and surface area of the prepared nanocomposites. The nanomaterials prepared using agricultural waste products shows desirable characteristics in all aspects which makes them equally applicable in energy storage devices, food packaging, drug delivery systems, nanosensors and water filtration systems.
Revamp of masonry structures using bio-additive infused air lime mortar as an applicator
Authors: Manoharan Abirami , Umarani C , Renuka S M
Published: June 2023

Lime masonry walls have been the initial type of masonry wall construction in the construction era. The minimally processed limestone extracted from the lime quarries gives a lesser carbon footprint than any other present-day construction material, making it superior to other construction materials in the construction industry and is the need of the hour. In this study, naturally fermented Bio-Additives, Jaggery and kadukkai were used to make lime mortar for the masonry prisms and walls, and the strength performance was investigated. The bio-additive and the lime powder combination were studied using a pH meter and pH strips to confirm their acidic/basic nature. The lime mortar was experimented with for its flexural strength using a beam specimen. The masonry prism study was initially made with stacked prisms and wall panels (English bond and Flemish bond) for testing compressive strength. The lime mortar thicknesses were varied into two for all the specimens of 10 mm and 15 mm for both the head and bed joints of the masonry. The experimental analysis revealed that a mortar thickness of 10 mm masonry increased the wall’s strength more than mortar of 15 mm thickness in the masonry, disproving the myth that higher mortar thickness in masonry increases the strength of the masonry. The mineralogical characterization of the mortar was carried out by SEM-EDAX to know the internal composition and morphological reactions, FTIR for the changes in the organic composition, and DSC-TGA to know the thermal properties of the mortar matrix. This study justifies the use of bio-additives-infused lime mortar for contemporary masonry projects.
EEG motor imagery classification using deep learning approaches in naïve BCI users
Authors: Guerrero-Mendez Cristian D , Blanco-Diaz Cristian F , Ruiz-Olaya Andres F , López-Delis Alberto , Jaramillo-Isaza Sebastian , Milanezi Andrade Rafhael , Ferreira De Souza Alberto , Delisle-Rodriguez Denis , Frizera-Neto Anselmo , Bastos-Filho Teodiano F
Published: June 2023

Motor Imagery (MI)-Brain Computer-Interfaces (BCI) illiteracy defines that not all subjects can achieve a good performance in MI-BCI systems due to different factors related to the fatigue, substance consumption, concentration, and experience in the use. To reduce the effects of lack of experience in the use of BCI systems (naïve users), this paper presents the implementation of three Deep Learning (DL) methods with the hypothesis that the performance of BCI systems could be improved compared with baseline methods in the evaluation of naïve BCI users. The methods proposed here are based on Convolutional Neural Network (CNN), Long Short-Term Memory (LSTM)/Bidirectional Long Short-Term Memory (BiLSTM), and a combination of CNN and LSTM used for upper limb MI signal discrimination on a dataset of 25 naïve BCI users. The results were compared with three widely used baseline methods based on the Common Spatial Pattern (CSP), Filter Bank Common Spatial Pattern (FBCSP), and Filter Bank Common Spatial-Spectral Pattern (FBCSSP), in different temporal window configurations. As results, the LSTM-BiLSTM-based approach presented the best performance, according to the evaluation metrics of Accuracy, F-score, Recall, Specificity, Precision, and ITR, with a mean performance of 80% (maximum 95%) and ITR of 10 bits/min using a temporal window of 1.5 s. The DL Methods represent a significant increase of 32% compared with the baseline methods (p < 0.05). Thus, with the outcomes of this study, it is expected to increase the controllability, usability, and reliability of the use of robotic devices in naïve BCI users.
Using google street view panoramas to investigate the influence of urban coastal street environment on visual walkability
Authors: Huang Gonghu , Yu Yiqing , Lyu Mei , Sun Dong , Zeng Qian , Bart Dewancker
Published: June 2023

Urban street walkability can effectively promote public health and the construction of livable cities. In addition, the coastal streets play a positive role in showing urban vitality and image. Due to the growing leisure needs of residents, measuring the visual walkability perception (VIWP) in urban streets and exploring the influence mechanisms of urban coastal street environments on VIWP have theoretical and practical significance. However, the methods of the previous walkability studies have limitations in terms of cost, time and measurement scale. Based on Google Street View Panoramic (GSVP) image data, this study used the semantic difference (SD) method with virtual reality (VR) technology to evaluate the VIWP of Fukuoka coastal streets. Meanwhile, the proportion of streetscape elements was extracted from GSVP images by semantic segmentation. The correlation and regression analyses were performed between the VIWP evaluation values and streetscape elements. Then, the regression model of the VIWP and the streetscape elements was established. The results showed that the natural features had a positive influence on VIWP in coastal streets. Correspondingly, trees were the strongest contribution rate for the VIWP, followed by shrubs, grasses and water, however, buildings and cars had a negative influence on VIWP. The method extends previous studies for measuring walkability, and optimization strategies were proposed to improve the visual quality of the coastal streets. It can be applied in the construction and management of walkable coastal street environments.
Wear factors and mechanisms of L-80 steel casings
Authors: Osman Omer Alnoor , Merah Necar , Samad Mohammed Abdul , Baig Mirza Murtuza Ali , Samuel Robello , Alshalan Meshari , Alshaarawi Amjad
Published: June 2023

Casing wear in directional drilling is inevitable and may result in catastrophic failure of the casing column. It is thus essential to understand its mechanisms and quantify its extent by estimating the casing wear factor. In this research, actual field casing samples, drilling pipe joints and muds were considered. An in-house built testing facility was used to test several L-80 casing samples by considering three rotational speeds of the drill pipe tool joint (DP-TJ) (115, 154, and 207 rpm) and three side loads (1000 N, 1200 N and 1400 N). The influence of the water- and oil-based muds on the coefficient of friction, wear volume, wear factor and wear mechanisms were investigated. The results revealed that under water-based mud (WBM) lubrication casing wear volume and wear factors were more than twice that of oil-based mud (OBM) lubrication. Moreover, it was observed that as the side load increased under both OBM and WBM lubrication at a constant rpm, both wear volume and wear factor increased. However, increasing the rotational speed while maintaining the side load constant decreased the wear factor, owing to the localized softening effect caused by the high heat generation at the contact area and the possible hydrodynamic lubrication regime change at higher speeds. The analysis of the digital microscopic images taken at the wear region shows that abrasive mechanism was dominant in the case of OBM lubrication. On the other hand, both abrasive and adhesive wear mechanisms were present under WBM lubrication.
Habits and Reflective Processes in COVID-19 Transmission-reducing Behaviors: Examining Theoretical Predictions in a Representative Sample of the Population of Scotland
Authors: den Daas Chantal , Dixon Diane , Hubbard Gill , Allan Julia , Johnston Marie
Published: June 2023

Background

Based on theory, COVID-19 transmission-reducing behaviors (TRBs) should become habitual because of their frequent performance. Habits have been hypothesized to develop through reflective processes and, to act in conjunction with them.

Purpose

We investigated the existence, development, and consequences of TRB habits, for physical distancing, handwashing, and wearing face coverings.

Methods

A representative sample of the Scottish population (N = 1,003) was interviewed by a commercial polling company in August–October 2020 and half were re-interviewed later. Measures included adherence, habit, personal routine tendency, reflective processes, and action control for three TRBs. Data were analyzed using general linear modeling, regression, and mediation analyses.

Results

Handwashing was most habitual; only face covering became more habitual over time. Routine tendencies predicted TRB habits, and adherence to handwashing and physical distancing. Those reporting greater habits reported better adherence, for physical distancing and handwashing, and this remained true after controlling for previous adherence. Reflective and habit processes independently predicted adherence for physical distancing and handwashing; only reflective processes were independently predictive for face covering. The relationship between planning and forgetting and adherence was partly direct, and partly mediated by habit.

Conclusions

The results confirm hypotheses from habit theory including the role of repetition and of personal routine tendency in developing habits. They are consistent with dual processing theory in finding that both reflective and habit processes predict adherence to TRBs. Action planning partly mediated the relation between reflective processes and adherence. The COVID-19 pandemic has enabled the testing and confirmation of several theoretical hypotheses about habit processes in the enactment of TRBs.