bluuebunny/crossref_metadata_2025 huggingface dataset:
Navigating the magnetic contribution of the commonly used single-crystal substrates SrTiO3(100) and LaAlO3(100) in weak magnetic thin films
Authors: Mandal Arup Kumar , Sarkar Sumit , Chandra M , Mandal Snehal , Chowdhury Sourav , Jana Anupam , Bagri Anita , Bera Anup Kumar , Kumar Dileep , Das Indranil , Rajhunathan Rajamani , Phase D M , Choudhary R J
Published: March 2024

In recent years, thin films of weak ferromagnetic materials have been in huge demand; however, probing their magnetic characteristics has been difficult due to contributions from underlying substrates. In the present study, we have analyzed the magnetic properties of the commonly used single-crystal SrTiO3(100) and LaAlO3(100) substrates and performed a time-dependent annealing protocol in vacuum and ambient oxygen pressure to mitigate the intrinsic weak ferromagnetic contributions from these substrates arising due to the presence of disorder or defects such as vacancies in the pristine substrates. It is shown that after proper air annealing, the substrate magnetic background becomes diamagnetic. When such air-annealed diamagnetic substrates are used for the deposition of low-thickness films carrying low magnetic moments such as SrRuO3and SrMnO3thin films, their magnetic transitions are explicitly observed. The proposed annealing protocols help to improve the signal from weak magnetic samples. This allows us to analyze the film’s magnetic properties without worrying about the contribution from the substrate.
New aspects of femtosecond laser ablation of Si in water: a material perspective
Authors: Kumar Kanaka Ravi , Banerjee Dipanjan , Akkanaboina Mangababu , Goud R Sai Prasad , Anjum Arshiya , Prakash A P Gnana , Pathak Anand P , Soma Venugopal Rao , Rao S V S Nageswara
Published: March 2024

We report a study of the role of material’s conductivity in determining the morphology of nanoparticles and nanostructures produced by ultrafast laser ablation of solids. Nanoparticles and textured surfaces formed by laser ablation display a wide variation in size and morphology depending on the material. In general, these qualities can be grouped as to material type, insulator, semiconductor, or metal; although each has many other different material properties that make it difficult to identify the critical material factor. In this report, we study these nanoparticle/surface structural characteristics as a function of silicon (Si) resistivity, thus honing-in on this critical parameter and its effects. The results show variations in morphology, optical, and nonlinear properties of Si nanoparticles. The yield of colloidal Si nanoparticles increased with an increase in the conductivity of Si. Laser-induced periodic surface structures formed on ablated substrates are also found to be sensitive to the initial conductivity of the material. Further, the laser ablation of Gamma-irradiated Si has been investigated to verify the influence of altered conductivity on the formation of Si nanoparticles. These observations are interpreted using the basic mechanisms of the laser ablation process in a liquid and its intricate relation with the initial density of states and thermal conductivities of the target material.
Hole subband dispersions in a cylindrical Ge nanowire: exact results based on the axial Luttinger–Kohn Hamiltonian
Authors: Li (李 睿) Rui
Published: March 2024

Based on the Luttinger–Kohn Hamiltonian in the axial approximation, the transcendental equations determining the hole subband dispersions in a cylindrical Ge nanowire are analytically derived. These equations are more general than that derived using the spherical approximation, and are suitable to study the growth direction dependence of the subband dispersions. The axial approximation almost gives rise to the accurate low-energy subband dispersions for high-symmetry nanowire growth directions [001] and [111]. The perturbation correction from the non-axial term is negligible for these two directions. The lowest two subband dispersions can be regarded as two shifted parabolic curves with an energy gap at

k

z

=
0

for both growth directions [001] and [111]. At the position of the energy gap, the eigenstates for growth direction [111] are inverted in comparison with the normal eigenstates for growth direction [001]. A nanowire growth direction where the energy gap closes at

k

z

=
0

is predicted to exist between directions [001] and [111].
Bearing fault diagnosis under variable speed conditions on adaptive time frequency extraction mode decomposition
Authors: Huo Jiyuan , Yang Jianwei , Yao Dechen , Sun Runtao , Hu Zhongshuo , Chen Zhiheng , Gao Cheng
Published: March 2024

Improvements in measurement technology have made it possible to detect problems with rolling bearings more accurately, which is important to ensure that they work properly in mechanical systems under different variable speed conditions. Time–frequency distribution (TFD) methods are widely used in variable-speed rolling bearing fault diagnosis, we construct a new method: adaptive time frequency extraction mode decomposition (ATFEMD) by capturing the distinctive time–frequency information within the TFD through ridge extraction, subsequently, the reconstruction components are further refined into adaptive modes through the harmonic detection and noise testing process. This method is a time–frequency post-processing method that effectively solves the problems of time–frequency energy lack of concentration, poor robustness of instantaneous frequency extraction, and mode aliasing in signal decomposition. This article analyzes the simulated bearing vibration and test bench bearing vibration signals to demonstrate the performance of ATFEMD. Results indicated that the proposed method is characterized by strong robustness, and good feature extraction results compared to other methods.
Broadband light absorption by a hemispherical concentric nanoshell array
Authors: Jiang Xiaoyun , Fan Fei , Su Feng , Mu Tianrui , Huang Chan , Zhou Leiming , Hu Jigang
Published: March 2024

Achieving highly efficient broadband absorption is an important research area in nanophotonics. In this paper, a novel method is proposed to design broadband near-perfect absorbers, consisting of a four-layer hemispherical concentric nanoshell array. The proposed nanostructure supports absorptivity exceeding 95% in the entire visible region, and the absorption bandwidth is determined by the interaction or ‘hybridization’ of the plasmons of the inner and outer metal-based nanoshells. Moreover, the designed absorber has wide-angle capability and is insensitive to polarization. The simple structure, as well as the stable absorption properties, suggests that such core–shell nanostructures can serve as a potential candidate for many applications such as solar energy harvesting, photo-detection, and emissivity control.
Maximum a posteriori detection of heartbeats from a chest-worn accelerometer
Authors: Schipper Fons , van Sloun Ruud J G , Grassi Angela , Brouwer Jan , van Meulen Fokke , Overeem Sebastiaan , Fonseca Pedro
Published: March 2024

Objective. Unobtrusive long-term monitoring of cardiac parameters is important in a wide variety of clinical applications, such as the assesment of acute illness severity and unobtrusive sleep monitoring. Here we determined the accuracy and robustness of heartbeat detection by an accelerometer worn on the chest. Approach. We performed overnight recordings in 147 individuals (69 female, 78 male) referred to two sleep centers. Two methods for heartbeat detection in the acceleration signal were compared: one previously described approach, based on local periodicity, and a novel extended method incorporating maximum a
posteriori estimation and a Markov decision process to approach an optimal solution. Main results. The maximum a
posteriori estimation significantly improved performance, with a mean absolute error for the estimation of inter-beat intervals of only 3.5 ms, and 95% limits of agreement of −1.7 to +1.0 beats per minute for heartrate measurement. Performance held during posture changes and was only weakly affected by the presence of sleep disorders and demographic factors. Significance. The new method may enable the use of a chest-worn accelerometer in a variety of applications such as ambulatory sleep staging and in-patient monitoring.
Electrical, optical and mechanical properties of monolayer MoTe2 for applications in wearable optoelectronic devices
Authors: Zhang Zhekai , Zhao Tian-Long , Ma Xiangchao , Zhao Zihan , Jian Chaochao , Dai Xianying , Song Jianjun
Published: March 2024

Transition metal dichalcogenides (TMDs) have excellent optical and mechanical properties and have potential application value in wearable optoelectronic response devices. MoTe2, a representative material of TMDs, is studied by first-principles calculation in this paper. The results show that the MoTe2 monolayer has a direct band gap of 1.110eV, which has a strong light absorption capacity and can produce a high concentration of photogenerated charge carriers after light absorption. The material is soft and exhibits the unique mechanical properties of layered materials. The effects of biaxial strain and defects on the properties of the materials were analyzed. The results show that the biaxial compression strain can enhance the light absorption curve of the material, enhance the light absorption of the photogenerated carrier, and expand the range of its energy distribution. The tensile strain decreases the value of the photon absorption curve and decreases the range of energy distribution of photogenerated carriers. The Mo vacancy defect increases the absorption curve value in the low energy region and broadens the optical response range of the material. The two types of vacancy defects both induce a ‘discrete’ distribution of photogenerated carriers. The Mo vacancy significantly affects the elastic modulus and anisotropy properties of the material, resulting in the material changing from ductile to brittle. When Mo vacancy is added, the spatial distribution of the elastic modulus of the material also changes greatly. Therefore, MoTe2 has potential application in flexible optoelectronic devices, and its performance can be controlled by strains and defects.
Generating superposition of squeezed states and photon-added squeezed states
Authors: Bohloul M , Dehghani A , Fakhri H
Published: March 2024

The scheme of an arrangement is considered for the preparation of some non-classical superposed states from squeezed states by using the optical parametric amplifier (OPA) apparatus, which is based on an idea recently proposed to generate photon-added states from the coherent states of light. This technique allows one to obtain linear combinations of squeezed vacuum states (SVSs) and n-photon-added squeezed vacuum states (n-PASVSs), that can enrich the non-classicality of the SVSs and n-PASVSs and improve their performances in quantum information protocols. Their characteristics are greatly affected by the gain of the OPA and the coherent field amplitude (or, mean number of photons). For this purpose, a comprehensive analysis of the non-classical features of these states has been presented in four different behavioral regimes, i.e. low- and high-gain regimes in the presence of weak and strong coherent fields. Finally, the role of the gain parameter of the light state from OPA as one of the input states of the Mach–Zehnder interferometer (MZI) apparatus in phase sensitivity optimization is discussed.
Exact Green’s function for 2D dirac oscillator in constant magnetic field within curved snyder space, and its thermal properties
Authors: Benzair Thouiba , Chohra Thouraia , Boudjedaa Tahar , Merad Mahmoud
Published: March 2024

Following the path integral approach, and in the context of curved Snyder space, we formulate the Green function for a (1+1)-dimensional Dirac oscillator system subject to a homogeneous magnetic field. Using the radial coordinates transformation the Green function and the electron propagator are calculated. Consequently, the exact bound states and their corresponding spectral energies are extracted. Our analysis has revealed that, under specific conditions when

m

ω

¯

→
m

ω

c

/

2

and c → V

F
, the behavior of the Dirac oscillator system in the presence of a uniform magnetic field within the SdS algebra closely resembles the dynamics of the monolayer graphene problem in the same algebraic framework. At high temperatures, the thermodynamic properties of the electron gas in the four cases of deformation parameters were extracted. The effect of the deformation parameters on these properties are tested, and also the limit cases for small parameters were inferred.
Superdeformation and dynamical symmetry
Authors: Riczu G , Darai J , Cseh J
Published: March 2024

Superdeformed bands are determined from symmetry-considerations, and their in-band E2 transition strengths are predicted. Those light nuclei are studied which were investigated from the experimental side, and comparison can be made with observed data. The SU(3) symmetry seems to organize the experimental finding to a good approximation.
Ion-acoustic solitary waves in Mars’ lower ionosphere
Authors: Elgohary Hala E , Farag Omar F , Moslem Waleed M
Published: March 2024

This study suggests that ionic species dynamics generate electrostatic ion-acoustic solitary waves (IASWs) in Mars’ lower ionosphere. It has been determined through observations that the lower ionosphere of Mars, specifically between 200 and 350 km above the surface, is mostly made up of ions like

O

2

+

, O
+, and

CO

2

+

, along with superthermal electrons. This study investigates the occurrence, propagation, and properties of IASWs. The derivation of the evolution equation is conducted for waves with a small-but-finite-amplitude. In order to analyze IASWs with large amplitude, the Sagdeev pseudo-potential is obtained. The model predicts the propagation of electrostatic IASWs within an electric field range of 1 to 6 mV/m and a pulse duration period of 0.5 to 4 ms. Fast Fourier analysis of the electric field pulse reveals pulses from 0.8 to 4 kHz.
Effects of caudal fin stiffness on optimized forward swimming and turning maneuver in a robotic swimmer
Authors: Deng Hankun , Li Donghao , Panta Kundan , Wertz Andrew , Priya Shashank , Cheng Bo
Published: March 2024

In animal and robot swimmers of body and caudal fin (BCF) form, hydrodynamic thrust is mainly produced by their caudal fins, the stiffness of which has profound effects on both thrust and efficiency of swimming. Caudal fin stiffness also affects the motor control and resulting swimming gaits that correspond to optimal swimming performance; however, their relationship remains scarcely explored. Here using magnetic, modular, undulatory robots (μBots), we tested the effects of caudal fin stiffness on both forward swimming and turning maneuver. We developed six caudal fins with stiffness of more than three orders of difference. For a μBot equipped with each caudal fin (and μBot absent of caudal fin), we applied reinforcement learning in experiments to optimize the motor control for maximizing forward swimming speed or final heading change. The motor control of μBot was generated by a central pattern generator for forward swimming or by a series of parameterized square waves for turning maneuver. In forward swimming, the variations in caudal fin stiffness gave rise to three modes of optimized motor frequencies and swimming gaits including no caudal fin (4.6 Hz), stiffness <10−4 Pa m4 (∼10.6 Hz) and stiffness >10−4 Pa m4 (∼8.4 Hz). Swimming speed, however, varied independently with the modes of swimming gaits, and reached maximal at stiffness of 0.23 × 10−4 Pa m4, with the μBot without caudal fin achieving the lowest speed. In turning maneuver, caudal fin stiffness had considerable effects on the amplitudes of both initial head steering and subsequent recoil, as well as the final heading change. It had relatively minor effect on the turning motor program except for the μBots without caudal fin. Optimized forward swimming and turning maneuver shared an identical caudal fin stiffness and similar patterns of peduncle and caudal fin motion, suggesting simplicity in the form and function relationship in μBot swimming.
Long-term observation of polycaprolactone small-diameter vascular grafts with thickened outer layer and heparinized inner layer in rabbit carotid arteries
Authors: Xiao Yonghao , Jin Xin , Jia Liujun , Li Jubo , Zhang Baojie , Geng Xue , Ye Lin , Zhang Ai-ying , Gu Yongquan , Feng Zeng-guo
Published: March 2024

In our previous study, the pristine bilayer small-diameter in situ tissue engineered vascular grafts (pTEVGs) were electrospun from a heparinized polycaprolactone (PCL45k) as an inner layer and a non-heparinized PCL80k as an outer layer in the thickness of about 131 μm and 202 μm, respectively. However, the hydrophilic enhancement of inner layer stemmed from the heparinization accelerated the degradation of grafts leading to the early formation of arterial aneurysms in a period of 3 months, severely hindering the perennial observation of the neo-tissue regeneration, host cell infiltration and graft remodeling in those implanted pTEVGs. Herein to address this drawback, the thickness of the outer layers was increased with PCL80k to around 268 μm, while the inner layer remained unchangeable. The thickened TEVGs named as tTEVGs were evaluated in six rabbits via a carotid artery interpositional model for a period of 9 months. All the animals kept alive and the grafts remained patent until explantation except for one whose one side of arterial blood vessels was occluded after an aneurysm occurred at 6 months. Although a significant degradation was observed in the implanted grafts at 9 month, the occurrence of aneurysms was obviously delayed compared to pTEVGs. The tissue stainings indicated that the endothelial cell remodeling was substantially completed by 3 months, while the regeneration of elastin and collagen remained smaller and unevenly distributed in comparison to autologous vessels. Additionally, the proliferation of macrophages and smooth muscle cells reached the maximum by 3 months. These tTEVGs possessing a heparinized inner layer and a thickened outer layer exhibited good patency and significantly delayed onset time of aneurysms.
The impact of tropical sea surface temperature on extreme precipitation in Pakistan during the summer of 2022
Authors: Luo Yulan , Liu Lin , Zhang Yun , Mehmood Shahbaz , Yang Yang , Yang Guang , Duan Yongliang , Li Qiuchi , Zeng Ai , Yu Weidong
Published: March 2024

In August 2022, Pakistan experienced an unprecedented precipitation event that caused significant damage. Analysis of the observations reveals that this extreme rainfall is primarily driven by anomalous atmospheric zonal advection, resulting in an anomalous water vapor concentration in Pakistan. The climatological meridional advection also contributes to this flooding. Anomalous easterly winds and low-level vertical convection combine to be critical factors contributing to the moisture concentration over the country. Further investigation identifies the air-sea interaction over the tropical Indian Ocean and abnormal warming over the Arabian Sea are crucial factors influencing this extreme flooding event. The concurrent occurrence of a negative Indian Ocean Dipole event and the warming sea surface temperature anomalies in the northern Arabian Sea intensifies the easterly winds over Pakistan, helping to transfer the anomalous water vapor from the remote region into Pakistan, ultimately contributing to the extreme flooding in 2022.
Wide-angle and Fano-shape contrast between emission and absorption in hybrid polariton-involved planar structure
Authors: Qian Liming , Xu Sicheng , Ye Jingfei , Pei Shixin , Zheng Gaige
Published: March 2024

Nonreciprocal light propagation in planar structure has become a hot topic because of the pattern-free fabrication process and the potentials for exploring heat transfer and energy management. An effective strategy incorporated with natural van der Waals material (α-phase molybdenum trioxide, α-MoO3), ultra-thin polar crystal (silicon carbide, SiC) thin film and a Weyl semimetal interlayer sitting on a metal (silver, Ag) substrate is proposed. The emission and absorption of the suggested device is explored with electromagnetic simulations that utilize the

4
×
4

transfer matrix method. Angular-resolved emission shows that the Fano-shape of nonreciprocity can be maintained within wide angle range. Tunable Fano resonances with different line shapes are demonstrated by varying the structural parameters. Moreover, the enhanced nonreciprocal radiation effect can be observed for both s- and p-polarized incidence waves. The proposal allows simultaneous control of spectral distribution and polarization of radiation, which will facilitate the active design and application of mid-infrared emitters.
Probing electron–phonon coupling in magnetic van der Waals material NiPS3: A non-magnetic site-dilution study
Authors: Pistawala Nashra , Kumar Ankit , Negi Devesh , Rout Dibyata , Harnagea Luminita , Saha Surajit , Singh Surjeet
Published: March 2024

NiPS3 is a van der Waals antiferromagnet which has been shown to exhibit spin-phonon and spin-charge coupling in the antiferromagnetically ordered state below TN = 155 K. It is also a rare Ni-based negative charge-transfer-type insulator with Ni valence in a linear superposition state

ψ
=

 

α

d
8

+

 

β

d
9

L

−

+

 

γ

 

d

10

L

−

2

, where

L

−

is the ligand hole. Here, we study high-quality single-crystals of Ni1−x
Zn
x
PS3 (0 < x < 0.2) using temperature-dependent specific heat and Raman spectroscopy probes. We show that in pristine NiPS3, the phonon mode at 176 cm−1 (P2), associated with the vibrations of Ni ions, exhibits a distinct Fano asymmetry. The Fano resonance is particularly pronounced in the paramagnetic phase above TN, which was further confirmed by temperature dependent Raman data on the Zn-doped crystals. In the Zn-doped crystals, while the magnetism weakens following the mean-field prediction for site-dilution in a honeycomb lattice, the Fano coupling

|

1

/

q

|

strengthens, increasing monotonically with increasing Zn-doping. The x-ray photoemission spectra suggest an increase in the weight of the

d
9

 

and

d

10

components in the Zn-doped crystals. These observations indicate the presence of strong electron–phonon coupling in Ni1−x
Zn
x
PS3, in addition to the spin-phonon, and spin-charge coupling previously reported.
Effect of Ni element on microstructure and properties of cold-rolled 316 L austenitic stainless steel
Authors: Zhang Xin , Xiao Yao , Cai Yangchuan
Published: March 2024

In this current investigation, the impact of Nickel (Ni) on the microstructural attributes and properties of a cold-rolled 316 L sheet was examined. The microstructure and phase configuration of austenitic stainless steels, specifically 316 L and 316LNi, were meticulously characterized through the utilization of metallography, X-ray Diffraction (XRD), and Electron Backscatter Diffraction (EBSD) techniques. Subsequent assessments were conducted to evaluate magnetic characteristics, microhardness, and tensile properties. The phase structure of both austenitic stainless steels conforms to a Face-Centered Cubic (FCC) crystal lattice, whereby the grain content oriented along the (110) plane progressively escalates with augmenting degrees of cold rolling. The magnetic conductivity of these austenitic stainless steels satisfactorily adheres to established standards. The incorporation of Nickel (Ni) into the alloy composition enhances the cold deformation capacity of 316 L stainless steel. However, substantial plastic deformation yields heightened dislocation density, thereby promoting enlarged grain dimensions upon solution treatment. Throughout subsequent cold rolling deformation sequences, the augmented grain size observed in 316LNi stainless steel leads to a reduction in dislocation density within the equivalently ordered cold-rolled plate. Simultaneously, this augmented grain size engenders a decline in grain boundary content coupled with an augmentation in twin content. Consequently, the interplay of grain coarsening, diminished dislocation density, and twin-induced softening collectively bestows upon 316LNi stainless steel a lower tensile strength compared to 316 L stainless steel, albeit accompanied by heightened plasticity.
Microstructure and mechanical behaviors of Gasar porous Cu/G4335V steel joint brazed by Ag-28Cu-0.75Ni alloy
Authors: Zhang Haiyan , Xia Chenping , Wang Dong , Yao Yangwu , Li Zaijiu , Xia Fengling
Published: March 2024

Cu/steel composites have the advantages of low cost and high heat dissipation performance, which make them ideal materials for applications in the industrial heat dissipation field. Because of the unique pore structure, the Gasar porous Cu is more excellent in heat transfer performance. However, systematic research still needs to be done on the joining technologies of Gasar porous Cu/steel. In this paper, Gasar porous Cu was joined to G4335V steel using Ag-28Cu-0.75Ni. The microstructure, shear strength, and fracture behavior of the Gasar porous Cu/G4335V steel joint were investigated. The results show that a clear interface of the brazed joint and no brazing defects were found. The joint microstructure mainly comprises α-Cu (ss.), β-Ag (ss.), and Ag-Cu eutectic phase. As the pore diameter of Gasar porous Cu increased, the joining area of the Gasar porous Cu/G4335V steel joint became larger, thereby improving the shear strength of the joint. For the same pore diameter, the shear strength of the mode 1 joint (The load direction and the pore direction are parallel to each other. The pore direction refers to the growth direction of the pore.) was higher than that of the mode 2 joint (The pore direction and the load direction are perpendicular to each other). The fracture analysis indicated that the joint crack was initiated in α-Cu (ss.) and propagated along the banded α-Cu (ss.). The joint fracture was a mixed fracture mechanism that combined ductile-brittle fractures.
Experimental optimization of machining GH4145 by atomizing discharge ablation milling
Authors: Tian Changliu , Li Yanan , Zhuo Xianghua
Published: March 2024

Atomizing discharge ablation milling (ADAM) technology is an efficient discharge machining technology derived from the traditional electrical discharge machining (EDM) method, which can be used to efficiently machine hard-to-machine materials such as nickel-based superalloy. In this present, the performance of machining nickel-based superalloy GH4145 by ADAM and Air near-dry EDM were compared, and the experimental results showed that the material removal rate (MRR) obtained by ADAM was nearly double that of the latter. A single-factor experiment were conducted to investigate the effect of electrode rotation speed on ADAM’s processing performance. Subsequently, an orthogonal experimental method was used to design the experiment. The signal-to-noise ratio analysis method was used to systematically study the performance characteristics of ADAM, including the influence of atomization amount, oxygen pressure, discharge current, duty ratio on MRR and tool electrode relative wear rate (TWR). The results showed that discharge current was the most influential processing parameter on MRR and TWR. Finally, the optimal combination of processing process parameters that met the requirements of various processing effect evaluation indicators were obtained and the correctness of the single objective optimization results was verified through experiments.
Effect of fibre treatment and moisture content on the vibration and acoustic properties of the basalt/hemp hybrid composites
Authors: Chakraborty Samanway , Padmaraj N H , I V Thara Reshma , Hegde Sriharsha
Published: March 2024

The hybridization reinforcements of composites allow design engineers to enhance the structural and acoustic properties of synthetic fibre-reinforced materials. Natural fibres are considered to have higher potential for replacing synthetic fibres in the composite industry. The present study aims to develop hybrid composite materials for sound insulation applications in the automotive industry. The hybrid composites were developed by reinforcing Basalt and Hemp fibres with Epoxy using vacuum bagging technique and cured under ambient conditions. Vibration and acoustic experiments were carried out on pristine and aged BHU (Basalt-Hemp-Untreated) and BHT (Basalt-Hemp-Treated) specimens. The fibre treatment and moisture gain influenced the natural frequency and stiffness of the hybrid composites. With the fibre treatment, the natural frequency of the specimens was enhanced by 12.8%. With ageing of both BHU and BHT, specimens showed a reduction in the natural frequency by 16.4% and 23% respectively. Moisture ingression into the composites reduced the stiffness and improved the damping factor of the structure. The aged BHU and BHT showed better acoustic performance compared to the pristine specimens.
Design of experiment approach to identify the dominant geometrical feature of left coronary artery influencing atherosclerosis
Authors: Ashrafee Adiba , Yashfe Syed Muiz Sadat , Khan Nusrat S , Islam Md Tariqul , Azam M G , Arafat M Tarik
Published: March 2024

Background and Objective. Coronary artery geometry heavily influences local hemodynamics, potentially leading to atherosclerosis. Consequently, the unique geometrical configuration of an individual by birth can be associated with future risk of atherosclerosis. Although current researches focus on exploring the relationship between local hemodynamics and coronary artery geometry, this study aims to identify the order of influence of the geometrical features through systematic experiments, which can reveal the dominant geometrical feature for future risk assessment. Methods. According to Taguchi’s method of design of experiment (DoE), the left main stem (LMS) length (l
LMS), curvature (k
LMS), diameter (d
LMS) and the bifurcation angle between left anterior descending (LAD) and left circumflex (LCx) artery (α
LAD-LCx) of two reconstructed patient-specific left coronary arteries (LCA) were varied in three levels to create L9 orthogonal array. Computational fluid dynamic (CFD) simulations with physiological boundary conditions were performed on the resulting eighteen LCA models. Average helicity intensity (h
2) and relative atheroprone area (RAA) of near-wall hemodynamic descriptors were analyzed. Results. The proximal LAD (LAD
proximal) was identified to be the most atheroprone region of the left coronary artery due to higher h
2, large RAA of time averaged wall shear stress (TAWSS < 0.4 Pa), oscillatory shear index (OSI ∼ 0.5) and relative residence time (RRT > 4.17 Pa−1). In both patient-specific cases, based on h
2 and TAWSS, d
lms is the dominant geometric parameter while based on OSI and RRT, α
LAD-LCx is the dominant one influencing hemodynamic condition in proximal LAD (p < 0.05). Based on RRT, the rank of the geometrical factors is: α
LAD-LCx > d
LMS > l
LMS > k
LMS, indicating that α
LAD-LCx is the most dominant geometrical factor affecting hemodynamics at proximal LAD which may influence atherosclerosis. Conclusion. The proposed identification of the rank of geometrical features of LCA and the dominant feature may assist clinicians in predicting the possibility of atherosclerosis, of an individual, long before it will occur. This study can further be translated to be used to rank the influence of several arterial geometrical features at different arterial locations to explore detailed relationships between the arterial geometrical features and local hemodynamics.
Marine-cloud brightening: an airborne concept
Authors: Claudel Christian , Lockley Andrew , Hoffmann Fabian , Xia Younan
Published: March 2024

Marine Cloud Brightening (MCB) is a proposed Solar Radiation Modification (SRM) geoengineering technique to enhance Marine Boundary Layer (MBL) cloud albedo. Extant proposals consider 104 − 105 autonomous ships spraying seawater, generating and dispersing sea salt nanoparticles. Alternatively, this paper proposes industrially manufacturing NaCl nanoparticles using ethanol anti-solvent brine precipitation. With desiccation, size optimization and narrowed size distribution, aerosol mass flux reduces by ∼500× (17× for dry mass flux). This facilitates Unmanned Aerial Vehicle delivery (e.g. MQ-9 Reaper Unmanned Aerial Vehicle). Increased speed and wake turbulence improves areal coverage per vehicle versus ships—reducing fleet size. Utilizing extant airframe designs improves vehicle Technology Readiness Level (TRL)—potentially improving system operational cost (est. $40B · yr
−1) and lead time. This approach further reduces energy requirements (5× less), technical risk and system complexity. Increased readiness amplifies proliferation risk—particularly for inexpensive regional heatwave and hurricane suppression—making governance more urgent.
Sodium-based di-chalcogenide: a promising material for tandem solar cells
Authors: Gómez-Ríos Danilo , Pérez-Walton S , López-Giraldo F E , Peralta J , Espinosa-García W F
Published: March 2024

Compounds based on chalcogen elements are widely studied currently due to their many interesting applications for electronic devices. The sodium-based dichalcogenide (NaNbS2) is a fascinating material with storage and conversion energy applications. In this paper, we conduct a first-principles investigation of the structural and thermodynamic stability and electronic properties of this material. We analyze a total of four structures to find the ground state using a fourth-order Birch–Murnaghan equation of state: the α and η related to the A-phase and the ζ
1 and ζ
2 related to the B-phase. We carefully address the exchange-correlation effects using the semi- local GGA-PBEsol targeted for solids. To analyze the electronic structure with higher accuracy, we implement the quasi-particle G

o

W

o

approximation. Our results for the fourth-order Birch–Murnaghan equation show that the most thermodynamically stable phase at zero temperature is α. To provide experimentalists insights about the possible routes to grow these materials, we calculated the convex hull of the α-model and ζ
1-model, finding that both are energetically stable. Finally, the calculated band gap with quasiparticle corrections for the α-model is 1.03 eV, which suggests possible applications of this material as a bottom cell in modern solar cells.
Design and parametric optimization of lead free perovskite based tandem solar cell for higher efficiency
Authors: Hussain Shahraan , Raj Balwinder , Sharma Divya
Published: March 2024

A critical concern is the creation of effective and eco-friendly photovoltaic materials. The non-toxic perovskite substance methyl ammonium germanium tri-iodide (MAGeI3) has several applications in tandem solar cells. In this research, the efficiency of a multi-junction tandem solar cell with MAGeI3 as the absorbent layer in the top cell and FeSi2 as the absorbent layer in the bottom cell was examined by a thorough simulation utilising SCAPS-1D software. The simulation took into account several variables, including the thickness, energy level, bandgap, and carrier concentration of the various layers. According to the simulation’s findings, the efficiency is 27.25% and the fill factor (FF) is around 80%. MAGeI3 is a safe and effective substitute material compared to other lead-containing perovskite materials. This work emphasises the potential of (MAGeI3) as a productive and eco-friendly component for tandem solar cells.
On the expressivity of embedding quantum kernels
Authors: Gil-Fuster Elies , Eisert Jens , Dunjko Vedran
Published: March 2024

One of the most natural connections between quantum and classical machine learning has been established in the context of kernel methods. Kernel methods rely on kernels, which are inner products of feature vectors living in large feature spaces. Quantum kernels are typically evaluated by explicitly constructing quantum feature states and then taking their inner product, here called embedding quantum kernels. Since classical kernels are usually evaluated without using the feature vectors explicitly, we wonder how expressive embedding quantum kernels are. In this work, we raise the fundamental question: can all quantum kernels be expressed as the inner product of quantum feature states? Our first result is positive: Invoking computational universality, we find that for any kernel function there always exists a corresponding quantum feature map and an embedding quantum kernel. The more operational reading of the question is concerned with efficient constructions, however. In a second part, we formalize the question of universality of efficient embedding quantum kernels. For shift-invariant kernels, we use the technique of random Fourier features to show that they are universal within the broad class of all kernels which allow a variant of efficient Fourier sampling. We then extend this result to a new class of so-called composition kernels, which we show also contains projected quantum kernels introduced in recent works. After proving the universality of embedding quantum kernels for both shift-invariant and composition kernels, we identify the directions towards new, more exotic, and unexplored quantum kernel families, for which it still remains open whether they correspond to efficient embedding quantum kernels.
Interdecadal variability of the pre-monsoon cyclone characteristics over the Bay of Bengal
Authors: Jena Biswajit , Pattnaik Sandeep
Published: March 2024

The low-pressure systems intensified to cyclones prior to the onset of the Indian summer monsoon season over the North Indian Ocean are referred to as pre-monsoon season (PMS) cyclones. Climate change is amplifying the pre-monsoon cyclone landscape, fostering more frequent and intense storms with altered tracks, resulting in heightened risks for coastal communities and economies. This study investigates the interdecadal variations in tropical cyclone and key large-scale atmospheric parameters that influence the characteristics of cyclones, including track, frequency over the Bay of Bengal (BoB) during the pre-monsoon season from 60 years of data. The large-scale atmospheric parameters are analyzed by calculating climatological anomalies. It is noted that the frequency of cyclones making landfall over the eastern Indian coastal landmass has increased in the recent decade compared to the past five decades. Compared to the past fifty years, the percentage frequency has increased in the recent ten years by 50%. At the low level, stronger easterlies are dominant and upper-level jet streams shift to lower latitudes, indicating that the path of cyclones has shifted from the north (N)-northeast (NE) to the northwest (NW), i.e. towards the east Indian coastal landmass, over the recent decade. In contrast to the previous five decades, an unusual low-pressure region has emerged over the NW India and Pakistan regions, creating a favorable path for cyclones moving towards the Indian region in recent decade. Cyclones have been more intense in the recent decade than they were in the previous five decades, according to the rise in low- and mid-level specific humidity and temperature over the BoB.
Highly stretchable kirigami-patterned nanofiber-based nanogenerators for harvesting human motion energy to power wearable electronics
Authors: Ning Chuan , Xiang Shengxin , Sun Xiupeng , Zhao Xinya , Wei Chuanhui , Li Lele , Zheng Guoqiang , Dong Kai
Published: March 2024

Wearable electronics are advancing towards miniaturization and flexibility. However, traditional energy supply methods have largely hindered their development. An effective solution to this problem is to convert human mechanical energy into electricity to power wearable electronic devices. Therefore, it is greatly attractive to design flexible, foldable and even stretchable energy harvesting devices. Herein, we use the electrospinning and kirigami approach to develop a type of highly stretchable kirigami-patterned nanofiber-based triboelectric nanogenerator (K-TENG). Due to its innovative structural design, the K-TENG can achieve a tensile strain of 220%, independent of the tensile properties of the material itself. When a person swings their arms, the K-TENG fixed to the clothing can convert mechanical energy from human movement into electrical energy. The produced electricity can directly drive 50 LED lights and a digital watch, or be stored in a lithium battery to charge the smartwatch and smartphone, respectively. This study employs a new method to fabricate a stretchable triboelectric nanogenerator and demonstrates its promising applications in wearable power technology.
Cardio-Ankle Vascular Index as a Marker of Left Ventricular Hypertrophy in Treated Hypertensives: Findings From the Pamela Study
Authors: Cuspidi Cesare , Facchetti Rita , Quarti-Trevano Fosca , Dell’Oro Raffaella , Mancia Giuseppe , Grassi Guido
Published: March 2024

BACKGROUND

Findings regarding the association between Cardio-Ankle Vascular Index (CAVI) and cardiac hypertension-mediated organ damage (HMOD), such as left ventricular hypertrophy (LVH) assessed by echocardiography, in elderly hypertensive patients are scanty. We sought to investigate this issue in the hypertensive fraction of the general population treated with anti-hypertensive drugs enrolled in the Pressioni Monitorate E Loro Associazioni (PAMELA) study.

METHODS

The study included 239 out of 562 participants who attended the second and third surveys of the PAMELA study performed after 10 and 25 years from the initial evaluation. Data collection included medical history, anthropometric parameters, office, home, ambulatory blood pressure (BP), blood examinations, echocardiography, and CAVI measurements.

RESULTS

In the whole study sample (age 69 ± 9 years, 54% males), CAVI was positively correlated with age, office, home, ambulatory systolic BP, LV mass (LVM) index, and negatively associated with body mass index (BMI). In multivariate analysis, CAVI was associated with the LVM index (P < 0.05) independently of major confounders. The participants with LVH exhibited significantly higher CAVI (10.6 ± 2.8 vs. 9.2 ± 1.8 m/s P < 0.001), larger left atrial diameter, and lower LV ejection fraction values than their counterparts without it. The CAVI value of 9.4 m/s was the best cut-off for prediction of LVH in the whole sample.

CONCLUSIONS

Our study provides new evidence of an independent association between CAVI and LVH in treated elderly hypertensive patients and suggests that the use of this metric of arterial stiffness could not only be used to evaluate vascular damage but also to stratify the risk of LVH.
MERITS: a web-based integrated Mycobacterial PE/PPE protein database
Authors: He Zhijie , Wang Cong , Guo Xudong , Sun Heyun , Bi Yue , Pitt Miranda E , Li Chen , Song Jiangning , Coin Lachlan J M , Li Fuyi
Published: March 2024

Motivation

PE/PPE proteins, highly abundant in the Mycobacterium genome, play a vital role in virulence and immune modulation. Understanding their functions is key to comprehending the internal mechanisms of Mycobacterium. However, a lack of dedicated resources has limited research into PE/PPE proteins.

Results

Addressing this gap, we introduce MycobactERIal PE/PPE proTeinS (MERITS), a comprehensive 3D structure database specifically designed for PE/PPE proteins. MERITS hosts 22 353 non-redundant PE/PPE proteins, encompassing details like physicochemical properties, subcellular localization, post-translational modification sites, protein functions, and measures of antigenicity, toxicity, and allergenicity. MERITS also includes data on their secondary and tertiary structure, along with other relevant biological information. MERITS is designed to be user-friendly, offering interactive search and data browsing features to aid researchers in exploring the potential functions of PE/PPE proteins. MERITS is expected to become a crucial resource in the field, aiding in developing new diagnostics and vaccines by elucidating the sequence-structure-functional relationships of PE/PPE proteins.

Availability and implementation

MERITS is freely accessible at http://merits.unimelb-biotools.cloud.edu.au/.
GPro: generative AI-empowered toolkit for promoter design
Authors: Wang Haochen , Du Qixiu , Wang Ye , Xu Hanwen , Wei Zheng , Wang Xiaowo
Published: March 2024

Motivation

Promoters with desirable properties are crucial in biotechnological applications. Generative AI (GenAI) has demonstrated potential in creating novel synthetic promoters with significantly enhanced functionality. However, these methods' reliance on various programming frameworks and specific task-oriented contexts limits their flexibilities. Overcoming these limitations is essential for researchers to fully leverage the power of GenAI to design promoters for their tasks.

Results

Here, we introduce GPro (Generative AI-empowered toolkit for promoter design), a user-friendly toolkit that integrates a collection of cutting-edge GenAI-empowered approaches for promoter design. This toolkit provides a standardized pipeline covering essential promoter design processes, including training, optimization, and evaluation. Several detailed demos are provided to reproduce state-of-the-art promoter design pipelines. GPro's user-friendly interface makes it accessible to a wide range of users including non-AI experts. It also offers a variety of optional algorithms for each design process, and gives users the flexibility to compare methods and create customized pipelines.

Availability and implementation

GPro is released as an open-source software under the MIT license. The source code for GPro is available on GitHub for Linux, macOS, and Windows: https://github.com/WangLabTHU/GPro, and is available for download via Zenodo repository at https://zenodo.org/doi/10.5281/zenodo.10681733.
Information-incorporated gene network construction with FDR control
Authors: Wang Hao , Qiu Yumou , Guo Hongqing , Yin Yanhai , Liu Peng
Published: March 2024

Motivation

Large-scale gene expression studies allow gene network construction to uncover associations among genes. To study direct associations among genes, partial correlation-based networks are preferred over marginal correlations. However, FDR control for partial correlation-based network construction is not well-studied. In addition, currently available partial correlation-based methods cannot take existing biological knowledge to help network construction while controlling FDR.

Results

In this paper, we propose a method called Partial Correlation Graph with Information Incorporation (PCGII). PCGII estimates partial correlations between each pair of genes by regularized node-wise regression that can incorporate prior knowledge while controlling the effects of all other genes. It handles high-dimensional data where the number of genes can be much larger than the sample size and controls FDR at the same time. We compare PCGII with several existing approaches through extensive simulation studies and demonstrate that PCGII has better FDR control and higher power. We apply PCGII to a plant gene expression dataset where it recovers confirmed regulatory relationships and a hub node, as well as several direct associations that shed light on potential functional relationships in the system. We also introduce a method to supplement observed data with a pseudogene to apply PCGII when no prior information is available, which also allows checking FDR control and power for real data analysis.

Availability and implementation

R package is freely available for download at https://cran.r-project.org/package=PCGII.