bluuebunny/crossref_metadata_2025 huggingface dataset:
Compact strontium atom source using fiber-based pulsed laser ablation
Authors: Osada A. , Tamaki R. , Lin W. , Nakamura I. , Noguchi A.
Published: May 2023

We designed, demonstrated, and characterized a strontium atom source based on fiber-based pulsed laser ablation. By using a commercially available miniature lens system for focusing nanosecond pulsed laser of up to 225 μ J delivered through a multimode fiber of 105 μm core, we ablate a SrTiO3 target and generate a jet of neutral strontium atoms, though our method can be applied to other transparent ablation targets containing materials under concern. Our device endures 6000 cycles of pulse delivery and irradiation without noticeable damage on the fiber facets and lenses. The generated strontium beam is characterized with a spectroscopic method and is revealed to exhibit the transverse temperature of 800 K and a longitudinal velocity of 2300 m/s, which are typical for a pulsed-laser-ablation-based atom source. The number of atoms generated by a single ablation pulse is estimated to be 2×105. Our device provides a compact, cryo-compatible fiber-pigtailed atom source with minimized device footprints and reduced complexity of vacuum systems to further promote development of cold-atom experiments. It may also find interesting applications in atomic and molecular sciences.
Semiclassical treatment of Feshbach resonances by transfer matrices
Authors: Kay Kenneth G.
Published: May 2023

A semiclassical method is presented for the calculation of Feshbach resonance positions and widths. This approach, based on semiclassical transfer matrices, relies only on relatively short trajectory fragments, thus avoiding problems associated with the long trajectories needed in more straightforward semiclassical techniques. Complex resonance energies are obtained from an implicit equation that is developed to compensate for the inaccuracy of the stationary phase approximation underlying the semiclassical transfer matrix applications. Although this treatment requires calculation of transfer matrices for complex energies, an initial value representation method makes it possible to extract such quantities from ordinary real-valued classical trajectories. This treatment is applied to obtain positions and widths for resonances in a model two-dimensional system, and the results are compared to those obtained from accurate quantum mechanical calculations. The semiclassical method successfully captures the irregular energy dependence of resonance widths that vary over a range of more than two orders of magnitude. An explicit semiclassical expression for the width of narrow resonances is also presented and serves as a simpler, useful approximation for many cases.
Dielectric relaxation and dielectric decrement in ionic acetamide deep eutectic solvents: Spectral decomposition and comparison with experiments
Authors: Maji Dhrubajyoti , Biswas Ranjit
Published: May 2023

Frequency-dependent dielectric relaxation in three deep eutectic solvents (DESs), (acetamide+LiClO4/NO3/Br), was investigated in the temperature range, 329 ≤ T/K ≤ 358, via molecular dynamics simulations. Subsequently, decomposition of the real and the imaginary components of the simulated dielectric spectra was carried out to separate the rotational (dipole–dipole), translational (ion–ion), and ro-translational (dipole–ion) contributions. The dipolar contribution, as expected, was found to dominate all the frequency-dependent dielectric spectra over the entire frequency regime, while the other two components together made tiny contributions only. The translational (ion–ion) and the cross ro-translational contributions appeared in the THz regime in contrast to the viscosity-dependent dipolar relaxations that dominated the MHz–GHz frequency window. Our simulations predicted, in agreement with experiments, anion-dependent decrement of the static dielectric constant (ɛs ∼ 20 to 30) for acetamide (ɛs ∼ 66) in these ionic DESs. Simulated dipole-correlations (Kirkwood g factor) indicated significant orientational frustrations. The frustrated orientational structure was found to be associated with the anion-dependent damage of the acetamide H-bond network. Single dipole reorientation time distributions suggested slowed down acetamide rotations but did not indicate presence of any “rotationally frozen” molecule. The dielectric decrement is, therefore, largely static in origin. This provides a new insight into the ion dependence of the dielectric behavior of these ionic DESs. A good agreement between the simulated and the experimental timescales was also noticed.
Hybrid bilayer plasmonic metasurfaces with intrinsic chiral optical responses
Authors: Li Zhancheng , Jiang Yifan , Liu Wenwei , Zhang Yuebian , Cheng Hua , Li Junjie , Tian Jianguo , Chen Shuqi
Published: May 2023

Plasmonic metasurfaces with giant chiral optical responses are good candidates for chirality study and application, which are usually composed of few-layer or three-dimensional nanostructures. Here, we demonstrate that hybrid bilayer plasmonic metasurfaces simply fabricated via a facile one-step nanofabrication process are good candidates for the realization of intrinsic chiral optical responses and spin-selective transmission. We prove that the intrinsic chiral optical response of the proposed metasurface, which can be easily manipulated, is attributed to the spin-selective collective interference of locally enhanced electric fields caused by the strong interlayer coupling. We further experimentally prove the advantages of fabricated hybrid bilayer plasmonic metasurfaces for optical encryption. With the advantages of compact design, chiral optical response easy to control and lower fabrication demand, the proposed metasurfaces can further expand the applications of chiral plasmonic nanostructures in the area of spin nanophotonics, nonlinear optics, and optical sensing.
The structure and electronic properties of tetrahedrally bonded hydrogenated amorphous carbon
Authors: Salek A. G. , Le P. Y. , Partridge J. G. , Raeber T. J. , Haberl B. , Boehler R. , Murdoch B. J. , Bradby J. E. , Ratcliff T. , Elliman R. G. , McKenzie D. R. , McCulloch D. G.
Published: May 2023

We have synthesized hydrogenated and deuterated amorphous carbon materials that have a density, 2.7 ± 0.1 g/cm3, consistent with almost entirely tetrahedral bonding. In hydrogen-free tetrahedral amorphous carbon, the presence of a minority of sp2 bonded atoms leads to localized states that could be passivated with hydrogen by analogy with hydrogenated amorphous silicon. Neutron diffraction analysis demonstrated that the local bonding environment is consistent with ab initio models of high density hydrogenated tetrahedral amorphous carbon and with the related tetrahedral molecular structure neopentane. The optical bandgap of our material, 4.5 eV, is close to the bandgap in the density of states determined by scanning tunneling spectroscopy (4.3 eV). This bandgap is considerably larger than that of hydrogen-free tetrahedral amorphous carbon, confirming that passivation of sp2 associated tail-states has occurred. Both the structural and electronic measurements are consistent with a model in which the tetrahedrally bonded carbon regions are terminated by hydrogen, causing hopping conductivity to dominate.
Holographic fluids: A thermodynamic road to quantum physics
Authors: Ván P.
Published: May 2023

Quantum mechanics, superfluids, and capillary fluids are closely related: It is thermodynamics that links them. In this paper, the Liu procedure is used to analyze the thermodynamic requirements. A comparison with the traditional method of divergence separation highlights the role of spacetime. It is shown that perfect Korteweg fluids are holographic. The conditions under which a complex field can represent the density and velocity fields of the fluid, and where the complex scalar field becomes a wave function of quantum mechanics, are explored. The bridge between the field and particle representations of a physical system is holography, and the key to holography is the Second Law of Thermodynamics.
Integrated sensing–memory–computing artificial tactile system based on force sensors and memristors
Authors: Xia Sheng-Yuan , Guo Liang-Yan , Long Yunfeng , Chen Weigen , Li Jian
Published: May 2023

Recently, numerous artificial tactile systems have been developed to mimic human tactile, employing force sensors in combination with external memory and computing units. However, the separated architecture of force sensing, memory, and computing results in high power consumption and significant delays, which pose a significant challenge for the development of efficient artificial tactile systems. In this study, we propose an integrated sensing–memory–computing artificial tactile system (smcATS) consisting of a graphene–polystyrene microparticle (G-PsMp) force sensor and an Ag-Fe3O4-ITO memristor. The design of the Ag-Fe3O4-ITO memristor with cross-shaped electrodes addresses the issue of micrometer-scale electrodes in conventional memristors that cannot be directly connected to force sensors. Furthermore, the smcATS demonstrates excellent properties of switching, endurance, and resistance–retention. Based on this, we have developed a visualized smcATS with a resistance state visualization circuit, which can better mimic skin bruising caused by strong external forces. Most importantly, the smcATS can avoid the need for analog-to-digital conversion and data transfer between separate memory and computing units, providing an alternative perspective for developing more efficient artificial tactile systems.
On the propagation and interaction of ion-acoustic solitary, periodic, shock, and breather waves in a non-Maxwellian electron–positron–ion magnetoplasma
Authors: Raut Santanu , Sarkar Tanay , Mali Prakash Chandra , Alotaibi Badriah M. , Ismaeel Sherif. M. E. , El-Tantawy S. A.
Published: May 2023

This investigation analyzes the propagation of nonlinear ion-acoustic waves (IAWs) in an unmagnetized, collisionless plasma composed of inertial positive ions and inertialess Maxwellian positrons as well as the inertialess non-Maxwellian electrons that obey (r, q)-distribution. To observe the impact of particle trapping on the nonlinear IAWs in an electron–positron–ion plasma, the Korteweg–De Vries (KdV) and modified KdV (mKdV) equations are derived using a reductive perturbation method. In the distribution function, the spectral parameters (r, q) put up their contribution to the flatness and high-energy tails, respectively. An important aspect of this investigation is the determination of well-known quasi-periodic solutions, multi-soliton solutions, breathers, and shocks under the variation of different physical parameters, especially spectral indices (r, q). Finally, the interaction of solitons is also presented for discussion of the complete profile. In addition, a detailed comparison, especially in a periodic wave, is made between the generalized (r, q)-distribution and the limiting cases of Kappa and Maxwellian distributions. The results presented in this study contribute to a better understanding of the characteristics of both high- and low-energy parts of the electron distribution function as well as the formation of periodic, soliton, multi-soliton, breathers, and shocks in space and astrophysical plasmas.
Do Australian state and territory cancer plans include survivorship-related objectives and propose quality survivorship outcomes and measures?
Authors: Petrie Megan , Kelly Helana , Jefford Michael
Published: May 2023

Objective This study reviewed Australian jurisdictional cancer plans to: (i) assess alignment of survivorship-related objectives with recommendations from the 2006 US Institute of Medicine (IOM) survivorship report, and (ii) identify objectives in assessing survivorship outcomes. Methods Current government cancer plans were identified and reviewed for inclusion of survivorship-related objectives, which were coded based on alignment with the 10 IOM recommendations, as well as content relating to outcome assessment and measurement. Results Twelve policy documents were identified from seven Australian states and territories. There was variability in the number of IOM recommendations addressed (between 3 and 8 of 10), the number of survivorship-related objectives (between 4 and 37 per jurisdiction) and the number of survivorship-related outcomes (between 1 and 25 per jurisdiction). Recommendations for raising awareness of survivorship, quality measures and models of survivorship care were more consistently addressed in jurisdictional plans. Recently updated plans appeared to have more survivorship-focused objectives. The importance of measuring survivorship outcomes was highlighted in all 12 cancer plans. Quality of life, other patient reported outcomes, and 5-year survival rates were the most commonly suggested outcomes. There was no consensus on metrics to assess survivorship outcomes, and little detail regarding how to measure proposed outcomes. Conclusion Almost all jurisdictions included survivorship-focused objectives within cancer plans. There was considerable variation in (i) alignment with IOM recommendations, and (ii) focus on survivorship-related objectives, outcomes and outcome measures. Opportunity exists for collaboration and harmonisation of work to develop national guidelines and standards of quality survivorship care.
A systematic assessment of the metallome of selected plant families in the Queensland (Australia) flora by using X-ray fluorescence spectroscopy
Authors: Purwadi Imam , Abubakari Farida , Brown Gillian K. , Erskine Peter D. , van der Ent Antony
Published: May 2023

Context Fewer than 10 plant species from Australia were known to hyperaccumulate metal(loid)s, despite metal-rich soils being widespread in Australia. By measuring herbarium specimens with non-destructive portable X-ray fluorescence spectroscopy (XRF) instrumentation their metal(loid)s concentrations can be determined, providing information that could be used to probe the evolution, biogeography, ecology, and physiology of plant species. Aims This study aimed to systematically measure herbarium specimens to obtain information on the prevailing concentrations of metal(loid)s in nearly 7000 plant specimens across seven plant families, and to link this data to an assessment of their spatial distribution. Methods The raw XRF spectrum of each herbarium specimen was processed using a new data-analysis pipeline recently validated for XRF data of herbarium specimens, to determine the concentrations of the first-row metal transition elements, and other detected elements. The collection localities of each of the herbarium specimens were plotted against rainfall and soil types to assess possible distributional patterns. Key results The results showed several newly discovered hyperaccumulator plant species, including 15 for manganese, two for nickel, three for cobalt, three for zinc, two for rare earth elements and one for selenium. Conclusions and implications Australia has more hyperaccumulator plant species than previously known and the XRF analysis of herbarium specimens is a powerful tool for their discovery. This research presents a new value proposition for the continued funding of herbarium collections in Australia and could initiate a range of research opportunities to use these data for future studies of plant evolution and adaptation.
Photocycloadditions of benzene derivatives and their systematic application to organic synthesis
Authors: Desvals Arthur , Hoffmann Norbert
Published: May 2023

Photocycloadditions of benzene derivatives with alkenes play an important role as key steps in organic synthesis. Intramolecular reactions have been most frequently studied in this context. Often, meta or [2 + 3] photocycloadditions take place in competition with ortho or [2 + 2] additions. The influence of the substitution pattern and the spin multiplicity of the excited state on the outcome of these reactions is discussed. A topological analysis permitting a systematic application of the [2 + 3] photocycloadditions to the total synthesis of natural products is presented and a selection of corresponding syntheses is discussed. More recently the [2 + 2] photocycloaddition and consecutive rearrangements on organic synthesis have been published. Some approaches in the context of asymmetric synthesis have also been reported.
Regional estimation of dead fuel moisture content in southwest China based on a practical process-based model
Authors: Fan Chunquan , He Binbin , Yin Jianpeng , Chen Rui
Published: May 2023

Background Dead fuel moisture content (DFMC) is crucial for quantifying fire danger, fire behaviour, fuel consumption, and smoke production. Several previous studies estimating DFMC employed robust process-based models. However, these models can involve extensive computational time to process long time-series data with multiple iterations, and are not always practical at larger spatial scales. Aims Our aim was to provide a more time-efficient method to run a previously established process-based model and apply it to Pinus yunnanensis forests in southwest China. Methods We first determined the minimum processing time the process-based model required to estimate DFMC with a range of initial DFMC values. Then a long time series process was divided into parallel tasks. Finally, we estimated 1-h DFMC (verified with field-based observations) at regional scales using minimum required meteorological time-series data. Key results The results show that the calibration time and validation time of the model-in-parallel are 1.3 and 0.3% of the original model, respectively. The model-in-parallel can be generalised on regional scales, and its estimated 1-h DFMC agreed well with field-based measurements. Conclusions Our findings indicate that our model-in-parallel is time-efficient and its application in regional areas is promising. Implications Our practical model-in-parallel may contribute to improving wildfire risk assessment.
Calibrating recipiency through pronominal reference
Authors: Dahmen Josua , Blythe Joe
Published: May 2023

Participants in conversation have a range of options for referring to co-conversationalists – lexical, grammatical, embodied – regardless of their language. Personal pronouns have been described as the most unmarked way of achieving reference, where little else is accomplished other than the action of referring. We demonstrate that speakers in a multi-party conversation whose language distinguishes between second and third-person pronouns, or between inclusive and exclusive pronouns, are constantly attributing and managing participation roles when referring to co-participants, even when using the default reference forms. Grammatical contrasts within pronoun inventories are recruited, often in conjunction with points and gaze, to indicate which co-participants are being addressed and which are being referred to. Address is constantly recalibrated through practices of reference. Speakers also draw on more marked referential expressions in order to emphasise the attribution of participation roles more explicitly. This study is based on a corpus of casual multi-party conversations in Jaru, an endangered Australian language with a dual pronominal system which encodes three grammatical numbers (singular, dual, and plural) and specifies whether the referents of first-person dual and plural pronouns exclude or include the addressee(s).
Positional identities negotiated within a collective identity
Authors: Shibata Miki
Published: May 2023

This qualitative study explores Japanese students’ positional identities in EMI contexts. Their positioning act is operated by the sociocultural norms of a program shared among community members. Individual semi-structured interviews were conducted with a total of 13 first-year students enrolled in an undergraduate English-taught program (ETP) at a Japanese national university. A thematic analysis of the interview data produced four main themes: (a) acting self-identification as a peripheral position, (b) hierarchy in a Japanese cohort, (c) an identity gap between the ideal self and reality, and (d) the ETP-A collective identity for membership negotiation. The study shows how participants position themselves and others based on English proficiency and academic culture, whereby students force themselves to acculturate for legitimate full participation. Such traits reflect collective identities and function as forms of sociocultural norms that determine legitimate membership. Furthermore, such norms lead to stratification between students: Japanese students identify themselves as inactive members of the ETP group with limited second-language (L2) English. Conversely, the collective identity helps them reclaim their ETP membership in Japanese-medium instruction classes with Japanese students from outside of the ETP. Japanese students’ positional identities are discussed in terms of L2 English competence and classroom culture.
Study on brazing WC-6Co/In718 with in-situ synthesis of Ni/Cu/AgCuNiMn solder
Authors: Liu Pan , Zhong Sujuan , Pei Yinyin , Zhang Guanxing , Mo Guidong , Wang Guoxin
Published: May 2023

Based on AgCuNiMn alloy, Ni/Cu/AgCuNiMn high-Ni solder was designed by in-situ synthesis. The WC-6Co/In718 joint was prepared by vacuum brazing at 950 °C for 10 min. The effect of metal foil on the filler metal filling ability, microstructure and mechanical properties of the joint was studied. The microstructure evolution and strengthening mechanism of the joint brazed with Ni/Cu/AgCuNiMn solder were analysed. The results showed that Ni element mainly plays a solution-strengthening role on the joint, and improve the interface bonding strength and the strength of Ag (s, s) distributed in the centre of the brazed joint, which increased the average tensile strength by 32.4% (from 426.5 to 564.7 MPa).
Intracellular trafficking of HLA-E and its regulation
Authors: He Wanlin , Gea-Mallorquí Ester , Colin-York Huw , Fritzsche Marco , Gillespie Geraldine M. , Brackenridge Simon , Borrow Persephone , McMichael Andrew J.
Published: May 2023

Interest in MHC-E–restricted CD8+ T cell responses has been aroused by the discovery of their efficacy in controlling simian immunodeficiency virus (SIV) infection in a vaccine model. The development of vaccines and immunotherapies utilizing human MHC-E (HLA-E)–restricted CD8+ T cell response requires an understanding of the pathway(s) of HLA-E transport and antigen presentation, which have not been clearly defined previously. We show here that, unlike classical HLA class I, which rapidly exits the endoplasmic reticulum (ER) after synthesis, HLA-E is largely retained because of a limited supply of high-affinity peptides, with further fine-tuning by its cytoplasmic tail. Once at the cell surface, HLA-E is unstable and is rapidly internalized. The cytoplasmic tail plays a crucial role in facilitating HLA-E internalization, which results in its enrichment in late and recycling endosomes. Our data reveal distinctive transport patterns and delicate regulatory mechanisms of HLA-E, which help to explain its unusual immunological functions.
Hydrodynamics of a Multi-Component Bosonic Superfluid
Authors: Zhang Fan , Yin Lan
Published: May 2023

We obtain the superfluid hydrodynamic equations of a multi-component Bose gas with short-ranged interactions at zero temperature under the local equilibrium assumption and show that the quantum pressure is generally present in the nonuniform case. Our approach can be extended to systems with long-range interactions such as dipole-dipole interactions by treating the Hartree energy properly. For a highly symmetric superfluid, we obtain the excitation spectrum and show that except for the density phonon, all other excitations are all degenerate. The implication of our results is discussed.
A note on the initial motion of a hanging string with an initial velocity at its free end
Authors: Rosales-Vera Marco
Published: May 2023

The initial movement of a hanging string is revisited through an integral transformation, the analysis of the integral solution allows to obtain some exact solutions for the string profile and to understand the physical meaning of the solutions. Finally, approximate solutions to the integral formula are found and compared with the numerical solution of the problem.
On a numerical construction of doubly stochastic matrices with prescribed eigenvalues
Authors: Rammal Kassem , Mourad Bassam , Abbas Hassane , Issa Hassan
Published: May 2023

We study the inverse eigenvalue problem for finding doubly stochastic matrices with specified eigenvalues. By making use of a combination of Dykstra’s algorithm and an alternating projection process onto a non-convex set, we derive hybrid algorithms for finding doubly stochastic matrices and symmetric doubly stochastic matrices with prescribed eigenvalues. Furthermore, we prove that the proposed algorithms converge, and linear convergence is also proved. Numerical examples are presented to demonstrate the efficiency of our method.
Rapid prototyping of microfluidics devices using novel thermoset polydicyclopentadiene
Authors: Song Guo , Weicheng Yang , Yong Luo
Published: May 2023

This study demonstrates the facile fabrication of microfluidic devices using novel thermoset polydicyclopentadiene (PDCPD). The fabrication process was accomplished using a strategy similar to soft lithography using polydimethylsiloxane (PDMS). The semi-cured PDCPD gel prepared from the thermal latent system of dicyclopentadiene retained the advantage of rapid and easy assembly via conformal contact, which is commonly achieved for devices fabricated from PDMS. Two methods were developed to form permanent bonding between PDCPD and PDMS, glass, and PDCPD, based on the polymerization of the semi-cured gel. The solvent compatibility of PDCPD was tested using various solvents over a period of 24 h, revealing excellent tolerance to acids, bases, alcohols, acetonitrile, ethyl acetate, and aliphatic hydrocarbons. However, PDCPD exhibited a low tolerance toward aromatic hydrocarbons, tetrahydrofuran, and chlorinated solvents. PDCPD devices demonstrated approximately 90% and 86% transmittance for 1 and 4 mm thick samples, respectively, in the visible-light region (400–800 nm). To further demonstrate the versatility of the material, droplets were generated on a PDCPD microfluidic device. This study confirmed the feasibility of using PDCPD as a routine material for the rapid prototyping of new designs.
Design and development of a piezoelectric driven micropump integrated with hollow microneedles for precise insulin delivery
Authors: Datta Arkaprava , Biswas Shatavisha , Dhar Riddhiman , Kanti Bhattacharyya Tarun
Published: May 2023

A significant rise in diabetes has spurred researchers to develop more painless, patient-friendly, precise therapeutic products for insulin delivery. There is extensive use of valveless micropumps in numerous medical devices since they constitute the key component in the microsystem for fluid control and precision delivery. This study reports a novel integrated insulin delivery device consisting of a valveless piezoelectric-driven micropump, a hollow microneedle array, and a fluid reservoir. At first, a simple, low-cost micropump driven by a piezoelectric disc is fabricated using 3D printing technology. Nozzle/diffuser elements are used instead of any active valves in order to avoid leakage and other complexities. To investigate the viability of the micropump, an analysis of the vibrational performance of the piezoelectric actuator is performed. COMSOL Multiphysics is used to perform the transient analysis of the piezoelectric actuator of the micropump. Further, simulation-based flow analyses are carried out to verify the outcomes of the experimental studies. The experimental results indicate that the maximum flow rate of the micropump is achieved at 400 Hz for insulin. To realize the final aim of this work, an array of hollow SU-8 microneedles is fabricated and then finally integrated with the piezoelectric-driven valveless micropump and fluid reservoir. This integrated insulin delivery device is tuneable and can achieve a maximum flow rate of 120.5 µl min−1 for insulin at 60Vpp, 400 Hz sine wave.
Dynamic long-period fiber grating through all-optical control based on MXene’s photothermal effect
Authors: Li Xiaokang , Liu Chi , Chong Yizhuo , Liao Xinya , Zhang Jiwei , Jiang Yajun , Du Bobo , Yang Dexing
Published: May 2023

Recently, two-dimensional (2D) transition metal carbide/nitride (MXene) materials have been found to have an outstanding photothermal conversion efficiency by virtue of excellent electromagnetic wave absorption capacity and a localized surface plasmon resonance effect. Integrated photonics and optoelectronic devices based on 2D materials such as MXene are the core of future industrial developments. Here, we report an attractive all-optical control of long-period fiber grating (LPFG) by taking advantage of MXene’s excellent photothermal conversion property. MXene is utilized as the photothermal tuning agent coated onto a bare section of LPFG. Experimental results reveal that the MXene-LPFG (MLPFG) is dynamic and the wavelength is tunable with external optical stimuli. The linear tuning sensitivity of wavelength is up to 72.6 pm mW−1. This all-optical controlled MLPFG is highly potential in optical filters, active devices, and optical modulators.
Influence of native defects on magneto-optoelectronic properties of α-MoO3
Authors: Sharma Poonam , Mishra Vikash , Shukla Alok
Published: May 2023

Semiconducting oxides possess a variety of intriguing electronic, optical, and magnetic properties, and native defects play a crucial role in these systems. In this study, we study the influence of native defects on these properties of α-MoO3 using the first-principles density functional theory calculations. From the formation energy calculations, it is concluded that Mo vacancies are difficult to form in the system, while O and Mo–O co-vacancies are energetically quite favorable. We further find that vacancies give rise to mid-gap states (trap states) that remarkably affect the magneto-optoelectronic properties of the material. Our calculations indicate that a single Mo vacancy leads to half-metallic behavior, and also induces a large magnetic moment of 5.98

μ

B

. On the other hand, for the single O vacancy case, the band gap disappears completely, but the system remains in a non-magnetic state. For Mo–O co-vacancies of two types considered in this work, a reduced band gap is found, along with an induced magnetic moment of 2.0

μ

B

. Furthermore, a few finite peaks below the main band edge are observed in the absorption spectra of configurations with Mo and O vacancies, while they are absent in the Mo–O co-vacancies of both types, just like in the pristine state. From the ab-initio molecular dynamics simulations, stability and sustainability of induced magnetic moment at room temperate is verified. Our findings will enable the development of defect strategies that maximize the functionality of the system and further help in designing highly efficient magneto-optoelectronic and spintronic devices.
A new rapid positioning strategy for the impact-point using dynamic mode decomposition and time difference of arrival
*
Authors: Bi Shengfan , Huang Yong , Wang Hao , Zhao Jinyu
Published: May 2023

In outdoor shooting range experiments, locating the projectile impact point is typically done through manual search, which can be time-consuming and costly. To improve experimental efficiency and reduce costs, this paper proposes a new approach for localizing the impact point using the dynamic mode decomposition (DMD) extension method and time difference of arrival (TDOA) based on seismic waves. The DMD extension method is applied to one-dimensional seismic signals. Additionally, diagonal averaging is applied to recover the reconstructed matrix, which could achieve better noise reduction than conventional singular value decomposition and empirical mode decomposition methods. Numerical simulations are then conducted to analyze the impact point positioning model, resulting in an absolute location error within 20 m in a 1000 m square area. The work demonstrates that the joint positioning algorithm combining on DMD and TDOA achieves high positioning accuracy, making it a promising tool for future experiments on outdoor shooting ranges.
Cellulose membrane coated Mo-doped TiO2 nanotube sheets for sustained oxidation of biomolecules
Authors: Shojai Sajjad , Meftahi Mohammad , Yousefi Reza , Moosavi-Movahedi Ali A , Haeri-Rohani Ali , Habibi-Rezaei Mehran
Published: May 2023

Titanium dioxide nanotubes (TNT) are widely researched materials for the photocatalytic generation of free radicals, which are useful in wastewater treatment. We aimed to prepare Mo-doped TNT sheets, covered with a cellulose membrane to avoid TNT surface inactivation by protein adsorption. We studied the susceptibility of serum albumin (SA) bound to different molar ratios of palmitic acid (PA) to denaturation and fibrillation by this system, which is meant to mimic oxidative stress conditions such as non-alcoholic fatty liver disease. The results demonstrated that cellulose membrane-covered TNT successfully oxidized the SA, identified by structural changes to the protein. Increasing the molar ratio of PA to protein-enhanced thiol group oxidation while protecting the protein against structural changes. Finally, we propose that in this photocatalyzed oxidation system, the protein is oxidized by a non-adsorptive mechanism mediated by H2O2. Therefore, we suggest that this system could be used as a sustained oxidation system to oxidize biomolecules as well as potentially in wastewater treatment.
SGReg: segmentation guided 3D/2D rigid registration for orthogonal X-ray and CT images in spine surgery navigation
Authors: Mi Jia , Yin Wenhao , Zhao Lei , Chen Yangfan , Zhou Yujia , Feng Qianjin
Published: May 2023

Objective. One of the essential technologies in various image-guided spine surgeries is the rigid registration of 3D pre-operative CT and 2D intra-operative X-ray images. The 3D/2D registration is patterned as two essential tasks, that is, dimensional correspondence establishment and estimation of the 3D pose. 3D data is projected to 2D for dimensional correspondence by most of the existing methods, which makes pose parameters difficult to estimate caused by the loss of spatial information. This work aims to develop a reconstruction based 3D/2D registration method for spine surgery navigation. Approach. A novel segmentation-guided 3D/2D registration (SGReg) method for orthogonal X-ray and CT images was proposed based on reconstruction. SGReg consists of a bi-path segmentation network and an inter-path multi-scale pose estimation module. The X-ray segmentation path in the bi-path segmentation network reconstructs 3D spatial information from 2D orthogonal X-ray images to segmentation masks; meanwhile, the CT segmentation path predicts segmentation masks from 3D CT images, thereby bringing the 3D/2D data into dimensional correspondence. In the inter-path multi-scale pose estimation module, the features from the two segmentation paths are integrated, and the pose parameters are directly regressed under the guidance of the coordinate information. Main result. We evaluated SGReg using a public dataset CTSpine1k and compared the registration performance with other methods. SGReg achieved considerable improvement over other methods with great robustness. Significance We have proposed an end-to-end 3D/2D registration framework named SGReg. Based on the idea of reconstruction, SGReg performs a unified framework between dimensional correspondence establishment and direct pose estimation in 3D space, showing significant potential in spine surgery navigation.
Optimized Monte Carlo simulations for voxel-based internal dosimetry
Authors: Cordeiro Leanderson P , de Sá Lidia V , Kitamikado Rafael A , Sapienza Marcelo T , B Bonifacio Daniel A
Published: May 2023

Objective. The scientific community has considered internal dosimetry by the Monte Carlo method the gold standard. However, there is a trade-off between simulation processing time and the statistical quality of the results that makes it a challenge to obtain accurate absorbed dose values in some situations, such as dose estimation in organs affected by cross-irradiation or limited computing power. Variance reduction techniques are used to reduce computational processing time without impairing the statistical quality of the results, such as tracking energy cutoff, secondary particle production threshold, and parallelism of different types of emissions from radionuclides. Approach. In this work, GATE Monte Carlo code and its variance reduction techniques were evaluated to calculate S values of organs from the international commission on radiological protection (ICRP) report 110 male phantom for the lutetium-177, iodine-131, yttrium-90, and radium-223 radionuclides. The results are compared with the data from the OpenDose collaboration. Main results. A cutoff of 5 MeV for local electron deposition and 2.0 mm of secondary particle production range resulted in a computational efficiency increase of 7.9 and 1.05 times, respectively. Simulation of ICRP 107 spectra-based source proved to be about 5 times more efficient when compared to a decay simulation using G4RadioactiveDecay (Geant4-based radioactive decay processes). Track length estimator (TLE) and split exponential track length estimator (seTLE) techniques were used to calculate the absorbed dose of photon emissions, resulting in computational efficiency up to 29.4 and 62.5 times higher when compared to traditional simulations, respectively. In particular, the seTLE technique accelerates the simulation time by up to 1426 times, achieving a statistical uncertainty of 10% in volumes affected by cross-irradiation. Significance. The variance reduction techniques used in this work drastically reduced the simulation time and maintained the statistical quality of the calculated absorbed dose values, proving the feasibility of the use of the Monte Carlo method in internal dosimetry under challenging situations and making it viable for clinical routine or web applications.
Fermi arc surface state and topological switch in the gyromagnetic metamaterials
Authors: Li Mingzhu , Han Ning , Qi Lu , Lin Zhuhong , Cui Songya , Chen Guang , Peng Liang
Published: May 2023

A landmark feature of the Weyl system is that it possesses the Fermi arc surface states. In this work, we demonstrate that the Fermi arc surface states connect the vacuum state and the Weyl points of gyromagnetic metamaterials (GMs). The nonzero Chern numbers and Berry phases show the nontrivial topological property of the GMs in momentum space. Full-wave simulations demonstrate that the chiral surface waves on the boundary between the GMs and vacuum state can achieve robustness against sharp corners of step-type configurations. Remarkably, the topological switch can be realized by adopting the Fermi arc surface states between two different GMs. We theoretically prove that the physical mechanism of realizing topological switch is caused by different gap Chern numbers of the material system. Moreover, the direction of the topological switch can be operated by manipulating the gyromagnetic parameters of the GMs in the ‘button’ region. Our work may provide more flexibility for the flexible and robust topological devices.
A microstructural slip analysis of radiative thermophoretic flow of ternary nanofluid flowing through porous medium
Authors: Madhukesh J K , Ramesh G K , Shehzad S A , Rauf A , Omar M
Published: May 2023

Slip flows play a vital role in the microsystems, such as micro-valves, micro-pumps, hard disc drives, and nozzles. As a result, this study aims to examine the micro-structural slip behavior of ternary nanoliquid flow past a stretchable surface. Linear radiation is included in the law of energy, whereas the law of mass treats thermophoretic particle decomposition. The nonlinear partial differential system is reduced to an ordinary differential system by executing the appropriate transformations. Using a shooting approach with the help of Maple software, the flow, heat mass transportation, and micro-rotation profiles are estimated numerically. The effect of varying parameters on the physical quantities distributions is discussed via graphical demonstrations. The presence of microstructural slip reduces the velocity and micro-rotation profiles, whereas the nanoparticle concentration and temperature increase. The incrementing thermal radiation values augmented the temperature distribution. The concentration field narrows due to thermophoretic constraints.
Enhancement of UV detection properties of ZnO thin films via Ni doping
Authors: Aboud Ahmed A , Bukhari Zahid , Al-Ahmadi Ameenah N
Published: May 2023

In this work, pure and Ni-doped ZnO thin films have been deposited onto glass substrates using the spray pyrolysis technique. All films were deposited at constant deposition parameters but the Ni content was changed from 0 to 7 weight (wt) %. XRD results revealed the formation of a hexagonal ZnO phase whilst no other phases were detected. The crystallite size was determined using Scherrer’s equation and found to be 45.9 nm for the pure film. Scanning electron microscope images show the formation of irregular grains with a broad size distribution. The existence of Ni in the deposited films was confirmed using energy dispersive spectroscopy (EDX), where the Ni content in the film increases as the weight % increases in the starting solution. The optical band gap was determined and found to be 3.3 eV for the pure ZnO films, which was reduced with Ni doping. The performance of the deposited films for UV radiation has been examined for the 365 nm wavelength and at different applied potentials and constant power. The rise and decay times for doped films were observed to exhibit faster rise/recovery as compared to pure films. The minimum response time was found to be 0.09 s for Ni-7 wt% film and the minimum decay time is 0.07 s for Ni-1 wt%.
Patient-specific quality assurance failure prediction with deep tabular models
Authors: Levin R , Aravkin A Y , Kim M
Published: May 2023

Purpose. Patient-specific quality assurance (PSQA) failures in radiotherapy can cause a delay in patient care and increase the workload and stress of staff. We developed a tabular transformer model based directly on the multi-leaf collimator (MLC) leaf positions (without any feature engineering) to predict IMRT PSQA failure in advance. This neural model provides an end-to-end differentiable map from MLC leaf positions to the probability of PSQA plan failure, which could be useful for regularizing gradient-based leaf sequencing optimization algorithms and generating a plan that is more likely to pass PSQA. Method. We retrospectively collected DICOM RT PLAN files of 968 patient plans treated with volumetric arc therapy. We constructed a beam-level tabular dataset with 1873 beams as samples and MLC leaf positions as features. We trained an attention-based neural network FT-Transformer to predict the ArcCheck-based PSQA gamma pass rates. In addition to the regression task, we evaluated the model in the binary classification context predicting the pass or fail of PSQA. The performance was compared to the results of the two leading tree ensemble methods (CatBoost and XGBoost) and a non-learned method based on mean-MLC-gap. Results. The FT-Transformer model achieves 1.44% Mean Absolute Error (MAE) in the regression task of the gamma pass rate prediction and performs on par with XGBoost (1.53 % MAE) and CatBoost (1.40 % MAE). In the binary classification task of PSQA failure prediction, FT-Transformer achieves 0.85 ROC AUC (compared to the mean-MLC-gap complexity metric achieving 0.72 ROC AUC). Moreover, FT-Transformer, CatBoost, and XGBoost all achieve 80% true positive rate while keeping the false positive rate under 20%. Conclusions. We demonstrated that reliable PSQA failure predictors can be successfully developed based solely on MLC leaf positions. FT-Transformer offers an unprecedented benefit of providing an end-to-end differentiable map from MLC leaf positions to the probability of PSQA failure.
Mitigation of adversarial attacks on voter model dynamics by network heterogeneity
Authors: Chiyomaru Katsumi , Takemoto Kazuhiro
Published: May 2023

Voter model dynamics in complex networks are vulnerable to adversarial attacks. In particular, the voting outcome can be inverted by adding extremely small perturbations that are strategically generated in social networks, even when one opinion is dominant over the other. However, the mitigation of adversarial attacks on the voter model dynamics in complex networks has not been thoroughly investigated. Thus, we examined network structures that could mitigate adversarial attacks using model networks and real-world networks, considering that the network structure affects the voter model dynamics. Numerical simulations demonstrated that the heterogeneity of node degrees in the networks (degree heterogeneity) significantly mitigates adversarial attacks. In particular, for complex networks with a power-law degree distribution

P
(
k
)
∼

k

−
γ

, the mitigation effect is significant for

γ
⩽
3

. However, the mitigation effect of the degree heterogeneity was relatively weak for large and dense networks. The degree correlation and clustering in the networks exhibited almost no mitigation effect. The results enhance our understanding of how opinion dynamics and collective decision-making are distorted in social networks and may be useful for considering defense strategies against adversarial attacks.
CX-Net: an efficient ensemble semantic deep neural network for ROI identification from chest-x-ray images for COPD diagnosis
Authors: Victor Ikechukwu Agughasi , S Murali
Published: May 2023

Automatic identification of salient features in large medical datasets, particularly in chest x-ray (CXR) images, is a crucial research area. Accurately detecting critical findings such as emphysema, pneumothorax, and chronic bronchitis can aid radiologists in prioritizing time-sensitive cases and screening for abnormalities. However, traditional deep neural network approaches often require bounding box annotations, which can be time-consuming and challenging to obtain. This study proposes an explainable ensemble learning approach, CX-Net, for lung segmentation and diagnosing lung disorders using CXR images. We compare four state-of-the-art convolutional neural network models, including feature pyramid network, U-Net, LinkNet, and a customized U-Net model with ImageNet feature extraction, data augmentation, and dropout regularizations. All models are trained on the Montgomery and VinDR-CXR datasets with and without segmented ground-truth masks. To achieve model explainability, we integrate SHapley Additive exPlanations (SHAP) and gradient-weighted class activation mapping (Grad-CAM) techniques, which enable a better understanding of the decision-making process and provide visual explanations of critical regions within the CXR images. By employing ensembling, our outlier-resistant CX-Net achieves superior performance in lung segmentation, with Jaccard overlap similarity of 0.992, Dice coefficients of 0.994, precision of 0.993, recall of 0.980, and accuracy of 0.976. The proposed approach demonstrates strong generalization capabilities on the VinDr-CXR dataset and is the first study to use these datasets for semantic lung segmentation with semi-supervised localization. In conclusion, this paper presents an explainable ensemble learning approach for lung segmentation and diagnosing lung disorders using CXR images. Extensive experimental results show that our method efficiently and accurately extracts regions of interest in CXR images from publicly available datasets, indicating its potential for integration into clinical decision support systems. Furthermore, incorporating SHAP and Grad-CAM techniques further enhances the interpretability and trustworthiness of the AI-driven diagnostic system.