bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization algorithm of UAV‐assisted federated learning resources based on wireless energy harvesting
Authors: Yuan Youhan , Zhu Qi
Published: November 2024

Federated learning (FL) enhances data privacy and security by enabling multiple terminals to collaboratively train a global model without transferring data to a central location. To tackle the challenges of limited terrestrial communication resources and device energy in FL, a UAV‐assisted federated learning and energy collection resource optimization algorithm is proposed. This algorithm harvests the working energy of FL terminals from radio frequency signals transmitted by the UAV via wireless energy collection. Considering energy causality and limited resources, we formulate a problem aimed at minimizing the completion time of FL training tasks. As this problem is NP‐hard, we initially employ a greedy algorithm to optimize the UAV's position, then decompose it into three sub‐problems: computing resources, power control, and bandwidth allocation. We derive and establish the optimization objective function for computing resources as convex, obtaining the expression for optimal computing resources. The Brent algorithm, based on golden section interpolation, iteratively solves the power distribution sub‐problem, while the Lagrange‐quasi‐Newton algorithm optimizes bandwidth allocation for each user. Simulation results demonstrate that the proposed algorithm effectively reduces training completion time while maintaining training quality.
A lightweight MMC topology with recombined half‐bridge submodules for DC fault ride‐through
Authors: Xu Yutao , Tan Zhukui , Li Jikai , Feng Qihui , Wu Zhuang
Published: November 2024

The lightweight of modular multilevel converter (MMC) and the DC faults ride‐through ability are main challenges for MMC‐high voltage direct current (HVDC) transmission systems. By introducing the concept of time‐division multiplexing, an arm multiplexing MMC (AM‐MMC) topology with high utilization of submodules is presented to reduce the weight and volume of MMC. In order to block the DC side fault current, this paper proposes a novel submodule in AM‐MMC, instead of using full‐bridge submodules. The proposed recombined half‐bridge submodules of AM‐MMC (RHAM‐MMC) contains four half‐bridge submodules and an IGBT with reverse parallel diodes. The topology and operating principle of RHAM‐MMC are introduced in detail. The time‐division multiplexing of middle arms between upper and lower arms is achieved by introducing arm selection switches. Thus, a new type of arm switch and switching method is designed based on the switch state. The DC faults ride‐through strategy is carried out based on its DC fault characteristic analysis. In addition, the economy analysis is conducted on the switching loss and operating loss of RHAM‐MMC. Compared with the fault ride‐through capability of other sub‐modules (SMs), RHAM‐MMC performs better in terms of investment cost and device losses. The simulation results based on MATLAB/Simulink reveal that RHAM‐MMC can achieve the DC side fault ride‐through and show effectiveness of the DC fault ride‐through control strategy.
The ANTARESS workflow
Authors: Bourrier V. , Delisle J.-B. , Lovis C. , Cegla H. M. , Cretignier M. , Allart R. , Al Moulla K. , Tavella S. , Attia M. , Mounzer D. , Vaulato V. , Steiner M. , Vrignaud T. , Mercier S. , Dumusque X. , Ehrenreich D. , Seidel J. V. , Wyttenbach A. , Dethier W. , Pepe F.
Published: November 2024

High-resolution spectrographs open a detailed window onto the atmospheres of stars and planets. As the number of systems observed with different instruments grows, it is crucial to develop a standard in analyzing spectral time series of exoplanet transits and occultations, for the benefit of reproducibility. Here, we introduce the ANTARESS workflow, a set of methods aimed at processing high-resolution spectroscopy datasets in a robust way and extracting accurate exoplanetary and stellar spectra. While a fast preliminary analysis can be run on order-merged 1D spectra and cross-correlation functions (CCFs), the workflow was optimally designed for extracted 2D echelle spectra to remain close to the original detector counts, limit the spectral resampling, and propagate the correlated noise. Input data from multiple instruments and epochs were corrected for relevant environmental and instrumental effects, processed homogeneously, and analyzed independently or jointly. In this first paper, we show how planet-occulted stellar spectra extracted along the transit chord and cleaned from planetary contamination provide a direct comparison with theoretical stellar models and enable a spectral and spatial mapping of the photosphere. We illustrate this application of the workflow to archival ESPRESSO data, using the Rossiter-McLaughlin effect Revolutions (RMR) technique to confirm the spin-orbit alignment of HD 209458b and unveil biases in WASP-76b’s published orbital architecture. Because the workflow is modular and its concepts are general, it can support new methods and be extended to additional spectrographs to find a range of applications beyond the proposed scope. In a companion paper, we will present how planet-occulted spectra can be processed further to extract and analyze planetary spectra decontaminated from the star, providing clean and direct measurements of atmospheric properties.
Impact of solar-wind turbulence on a planetary bow shock
Authors: Behar E. , Pucci F. , Simon Wedlund C. , Henri P. , Ballerini G. , Preisser L. , Califano F.
Published: November 2024

Context. The interaction of the solar-wind plasma with a magnetized planet generates a bow-shaped shock ahead of the wind. Over recent decades, near-Earth spacecraft observations have provided insights into the physics of the bow shock, and the findings suggest that solar-wind intrinsic turbulence influences the bow shock dynamics. On the other hand, theoretical studies, primarily based on global numerical simulations, have not yet investigated the global three-dimensional (3D) interaction between a turbulent solar wind and a planetary magnetosphere. This paper addresses this gap for the first time by presenting an investigation of the global dynamics of this interaction that provides new perspectives on the underlying physical processes.

Aims. We use the newly developed numerical code MENURA to examine how the turbulent nature of the solar wind influences the 3D structure and dynamics of magnetized planetary environments, such as those of Mercury, Earth, and magnetized Earth-like exoplanets.

Methods. We used the hybrid particle-in-cell code MENURA to conduct 3D simulations of the turbulent solar wind and its interaction with an Earth-like magnetized planet through global numerical simulations of the magnetosphere and its surroundings. MENURA runs in parallel on graphics processing units, enabling efficient and self-consistent modeling of turbulence.

Results. By comparison with a case in which the solar wind is laminar, we show that solar-wind turbulence globally influences the shape and dynamics of the bow shock, the magnetosheath structures, and the ion foreshock dynamics. Also, a turbulent solar wind disrupts the coherence of foreshock fluctuations, induces large fluctuations on the quasi-perpendicular surface of the bow shock, facilitates the formation of bubble-like structures near the nose of the bow shock, and modifies the properties of the magnetosheath region.

Conclusions. The turbulent nature of the solar wind impacts the 3D shape and dynamics of the bow shock, magnetosheath, and ion foreshock region. This influence should be taken into account when studying solar-wind-planet interactions in both observations and simulations. We discuss the relevance of our findings for current and future missions launched into the heliosphere.
Nested active regions anchor the heliospheric current sheet and stall the reversal of the coronal magnetic field
Authors: Finley A. J.
Published: November 2024

Context. During the solar cycle, the Sun’s magnetic field polarity reverses due to the emergence, cancellation, and advection of magnetic flux towards the rotational poles. Flux emergence events occasionally cluster together, although it is unclear if this is due to the underlying solar dynamo or simply by chance.

Aims. Regardless of the cause, we aim to characterise how the reversal of the Sun’s magnetic field and the structure of the solar corona are influenced by nested flux emergence.

Methods. From the spherical harmonic decomposition of the Sun’s photospheric magnetic field, we identified times when the reversal of the dipole component stalls for several solar rotations. Using observations from sunspot cycle 23 to present, we located the nested active regions responsible for each stalling and explored their impact on the coronal magnetic field using potential field source surface extrapolations.

Results. Nested flux emergence has a more significant impact on the topology of the coronal magnetic field than isolated emergences as it produces a coherent (low spherical harmonic order) contribution to the photospheric magnetic field. The heliospheric current sheet, which separates oppositely directed coronal magnetic fields, can become anchored above nested active regions due to the formation of strong opposing magnetic fluxes. Further flux emergence, cancellation, differential rotation, and diffusion, then effectively advects the heliospheric current sheet and shifts the dipole axis.

Conclusions. Nested flux emergence can restrict the evolution of the heliospheric current sheet and impede the reversal of the coronal magnetic field. The sources of the solar wind can be more consistently identified around nested active regions because the magnetic field topology remains self-similar for multiple solar rotations. This highlights the importance of identifying and tracking nested active regions to guide the remote-sensing observations of modern heliophysics missions.
High-resolution HI mapping of nearby extremely metal-poor blue compact dwarf galaxies
Authors: Scott Tom C. , Brinks Elias , Sengupta Chandreyee , Lagos Patricio
Published: November 2024

Aims. Optical observations of blue compact dwarf galaxies (BCDs) show they typically have high specific star formation rates (sSFRs) and low metallicites. A subset of these galaxies (those with the lowest gas phase metallicities) display cometary optical morphologies similar to those found at high redshift. Whether this combination of properties predominantly arises from interactions with neighbours or via accretion from the cosmic web, or is indeed due to something else, remains unclear. Our aim is to use high-resolution H I mapping to gain insights into the processes driving the observed properties of a sample of extremely metal-poor (XMP) BCDs.

Methods. We present Very Large Array B– and C–configuration H I mapping of the four BCDs of our sample. For three of the targeted BCDs, we also detected and mapped the H I in their nearby companions.

Results. In these three cases, there is H I morphological and kinematic evidence of a recent flyby interaction between the BCD and a nearby companion galaxy. The H I evidence for recent interactions for these three BCDs is corroborated by our analysis of the tidal forces exerted on the BCDs by companions with available spectroscopic redshifts. In one of these cases, J0204–1009, we obtain sufficient spatial resolution to determine that the BCD is dominated by dark matter (DM) and estimate its DM halo mass to be in the range of 1.2 × 1011 to 5.2 × 1011 M⊙. However, it is the most isolated BCD in our small sample, J0301–0052, that shows one of the most asymmetric H I morphologies. J0301–0052 has a similar cometary H I morphology to its optical morphology, although the H I column density maximum is projected at the end of the optical tail.

Conclusion. Our H I observations suggest that J0301–0052 may be undergoing a merger, while the other members of our BCD sample show evidence of a recent tidal interaction with a near neighbour. While our selection criteria favour BCDs with companions, our results are consistent with previous literature showing that most BCDs are associated with either mild tidal interactions or mergers.
Determinants for the viticultural systems sustainability
Authors: Marta-Costa Ana , Rodríguez Xosé A. , Santos Micael
Published: November 2024

The adoption of a sustainable approach has been recognized as a competitive and resilience factor for the vine and wine sector. This research aimed to address the variables that explain the sustainability of the viticultural systems practiced in the Douro Demarcated Region, in a dimensional and global perspective of sustainability. In total 110 vineyard farms were randomly selected and a matrix of sustainability indicators grouped by economic, environmental and social dimension was used. In order to analyse the main determinants of the different dimensions of sustainability, an econometric analysis was carried out considering different typologies or groups of determinants: efficiency; training system; vineyard landscaping; geographical determinants; destination of the grapes; type of work used; other determinants. Based on the estimations of eight models, an important divergence in the results was found, especially between the estimates of the models developed through the global sustainability index than the estimates of the indices disaggregated by dimension. This disparity in results indicates that the analysis of the determinants of sustainability should be carried out in a disaggregated manner (at the level of sustainability dimensions). Divergent results were also deduced depending on the dimension of sustainability. For instance, the model with the highest explanatory power concerned the economic dimension, while the efficiency determinant was not significant in the social and environmental dimensions. In light of these findings, policy measures are proposed.
Overview of the new capabilities in the Monte-Carlo particle-transport code NECP-MCX V2.0
Authors: He Qingming , Zheng Qi , Li Jie , Huang Zhanpeng , Huang Jinlong , Qin Shuai , Shu Hanlin , Peng Heyu , Yang Xuran , Shen Jingwen , Guo Jiandi , Cao Liangzhi , Wu Hongchun
Published: November 2024

NECP-MCX is a Monte-Carlo particle-transport code developed by the Nuclear Engineering Computational Physics (NECP) Lab. of Xi’an Jiaotong University in 2018. The first version of NECP-MCX is focused on addressing the challenge of deep-penetration radiation-shielding problems. In recent years, new capabilities of unstructured-mesh geometries, dose engine for Boron Neutron Capture Therapy (BNCT), neutron noise analysis, sensitivity analysis, depletion and activation calculation, simulation of randomly dispersed media, homogenization and gamma dose calculation based on point-kernel integral method are implemented in NECP-MCX V2.0. A user interface of NECP-MCX V2.0 is also under active development. This paper will introduce these new capabilities.
Effect of laser beam energy density distribution on the main properties of laser additive forming of metal parts
Authors: Hu Jing
Published: November 2024

Compared to traditional processing techniques, laser additive manufacturing technology has advantages such as short processing cycles, no molds, and is not limited by complex structures. However, the forming quality of GH3625 nickel-base alloy metal parts is affected by various process parameters, in which the distribution characteristics of laser beam energy density, microstructure and mechanical properties play a key role. In order to investigate the influence of beam energy density distribution on the main properties of GH3625 nickel-based alloy metal parts, the beam energy density distribution was changed by controlling the defocusing amount. Then it sets 5 different defocusing parameters to obtain the corresponding energy density distribution characteristics. Observing and analyzing the various properties of alloy powder from the perspectives of different scanning speeds, laser power, and energy density distribution characteristics. The results show that when the laser power is 600 W, the scanning speed is 700 mm/min, and the energy density distribution is characteristic 4, the metal parts have the best performance. Its density is 99.90%, microhardness is 350.44 HV, tensile strength is 1328 Mpa, friction coefficient is about 0.51, and wear rate is 0.55%. This indicates that the laser additive forming method proposed in this study can effectively improve the hardness, density and other properties of GH3625 nickel-based alloy metal parts to achieve the best state, which provides an important reference for the further optimization of the material preparation process.
Improve the sustainability of supply chain: the role of carbon abatement and blockchain technology
Authors: Yao Yunfei , Liu Tingting , Tian Guixian
Published: November 2024

This paper analytically explores a supply chain where a manufacturer sells products through a retail platform that can operate under either a reselling or agency selling model, corresponding to Scenarios R and A. The model incorporates consumer valuation discounts based on the platform’s retail channel and sensitivity to carbon emissions. The paper first examines the manufacturer’s investment decision in green technology to reduce carbon emissions and then analyzes the platform’s adoption of blockchain technology to disclose information about the manufacturer’s actions. The analysis shows that the manufacturer consistently prefers to invest in green technology over taking no action in both scenarios. However, the platform’s decision to adopt blockchain depends on consumer acceptance of the product: blockchain is deployed when consumer acceptance is high, and not when it is low. The study further identifies two key factors – consumer acceptance and environmental sensitivity – that critically influence the supply chain members’ choice of operational model. Specifically, as consumer acceptance of the product increases, both the manufacturer’s and platform’s preferences shift from Mode RN/RT (Reselling, No blockchain/Retail, No blockchain) to Mode RB (Reselling, Blockchain) and Mode RT (Agency, Blockchain) to Mode AB (Agency, Blockchain). Conversely, as consumer environmental sensitivity increases, preferences shift in the opposite direction, from Mode RB (Reselling, Blockchain) and Mode AB (Agency, Blockchain) to Mode RN/RT (Reselling, No blockchain) and Mode AN/AT (Agency, No blockchain). These findings highlight the interconnectedness of consumer attitudes toward sustainability and the operational decisions of supply chain members.
Wie sieht eine ideale Tagesstätte aus? Die Nutzenden-Perspektive auf
tagesstrukturierende Angebote für Menschen mit psychischen
Erkrankungen
Authors: Mötteli Sonja , Adamus Christine , Sutor Kim , Schärer Daniel , Richter Dirk
Published: November 2024

Ziel Tagesstätten für Menschen mit psychischen Beeinträchtigungen sind
weit verbreitet. Dennoch gibt es nur wenige Studien über ihre Nutzung und
Wirksamkeit. Diese Arbeit untersucht, wie eine ideale Tagesstätte aus Sicht der
Nutzenden aussehen sollte.

Methodik Es wurden 6 leitfadengestützte Fokusgruppen mit 4–8 Nutzenden
durchgeführt. Die Diskussionen wurden wörtlich transkribiert und mittels
qualitativer Inhaltsanalyse ausgewertet.

Ergebnisse Es nahmen 36 Personen teil (67% Frauen, 20–62 Jahre). Die
Tagesstätten erfüllten 5 Funktionen: Psychische Gesundheit verbessern,
Gemeinschaft erleben, Tagesstruktur erhalten, sinnvolle Beschäftigung und Aufbau
der Arbeitsfähigkeit. Die Ergebnisse zeigten wichtige Aspekte der Organisation,
der aktuellen und gewünschten Aktivitäten und der Unterstützung.

Schlussfolgerung Tagesstätten werden als elementarer Bestandteil der
intermediären psychiatrischen Versorgung betrachtet. Die Nutzenden haben klare
Vorstellungen davon, wie Tagesstätten ihre soziale und berufliche Rehabilitation
unterstützen können.
Unexpected Findings of Duchenne Muscular Dystrophy in Prenatal Screening of Chromosome Abnormality Based on Cell-Free Fetal DNA
Authors: Zhao Ganye , Liu Lina , Shi Panlai , Gu Mingxin , Yang Shaozhe , Kong Xiangdong
Published: November 2024

Objective This study aims to assess the feasibility of detecting and diagnosing Duchenne muscular dystrophy (DMD) during prenatal screening for chromosome abnormalities using cell-free fetal DNA extracted from peripheral blood samples of pregnant women.

Study Design Two pregnant women identified as high risk through noninvasive prenatal testing (NIPT) underwent amniocentesis to obtain fetal cells. Subsequent fetal chromosomal karyotyping was conducted, and genomic DNA from fetal cells was extracted for copy number variation sequencing (CNV-Seq) analysis, complemented by multiplex ligation-dependent probe amplification (MLPA) to detect deletions or duplications within the DMD gene.

Results NIPT results for the two samples indicated potential abnormalities involving chromosomes 21 and 18. However, karyotype analysis of the fetuses revealed no abnormalities. CNV-Seq identified deletions of 0.28 and 0.18 Mb within chromosome Xp21.1, encompassing the DMD gene, in each fetus. In family 1, MLPA results indicated a maternal heterozygous deletion spanning exons 12 to 41 in the DMD gene, while the fetus exhibited deletions in exons 12 to 41. In family 2, MLPA results confirmed normal DMD gene status in the pregnant woman's peripheral blood genomic DNA but revealed a fetal deletion spanning exons 48 to 52. Both fetuses were diagnosed with DMD and subsequently underwent termination.

Conclusion Abnormalities identified through NIPT necessitate further invasive prenatal diagnostic procedures. For cases involving chromosomal microdeletions or microduplications, a combination of karyotyping and CNV-Seq testing is essential for comprehensive diagnosis. NIPT followed by CNV-Seq may offer insights into large exon deletions within the DMD gene in specific instances.

Key Points
Effects of Neoadjuvant Radiation and Recipient Vessel Characteristics on Microvascular Complication Rates in Reconstruction of Lower Extremity Soft Tissue Sarcoma Defects
Authors: Farmer Rebecca L. , Easton Justin , Sanchez Ruston , Emanuelli Elisa , Mah Eldon
Published: November 2024

Background The treatment approach for soft tissue sarcomas (STS) of the lower extremity has shifted toward the use of neoadjuvant radiation combined with limb-sparing surgery (LSS). The resulting defects often require reconstruction with free tissue transfer for adequate outcomes. Data have demonstrated a potentially increased risk of microvascular complications for free flaps performed using irradiated recipient vessels. Similarly, certain anatomic areas of the lower extremity have a high proportion of unnamed perforators that are available as recipient vessels, increasing the technical difficulty. We aimed to determine if the characteristics of recipient vessels that were used for the reconstruction of STS defects influenced rates of microvascular complications in our patients.

Methods A retrospective chart review of all patients who underwent reconstruction of lower extremity STS defects with free tissue transfer from 2009 to 2020 was conducted. Data regarding recipient vessel type (axial vessel vs. unnamed perforator), radiation status of the recipient vessels (irradiated vs. non-irradiated), and microvascular complications were compared across groups.

Results A total of 204 free flaps were included. The overall microvascular complication rate was 13.7% (28 cases). Most microvascular complications were detected postoperatively (82.1%) rather than intraoperatively, with the majority involving venous congestion/thrombosis (20 cases, 71.4%). While there was a trend toward increased microvascular complications with the use of irradiated recipient vessels (27 cases, 96.4%), this did not reach statistical significance (OR = 1.98, p = 0.52). The use of perforating branches as recipient vessels did not confer an increased risk of microvascular complications (OR = 0.87, p = 0.75).

Conclusion The reconstruction of irradiated lower-extremity STS defects represents a particularly challenging issue. This analysis demonstrates that free tissue transfer can be safely performed using irradiated vessels without a significantly increased risk of microvascular complications. Furthermore, unnamed perforating branches can be successfully used for reconstruction in anatomically challenging areas of the lower extremity.
Coexistence of obesity and unhealthy cardiorespiratory fitness in a
cohort of boys
Authors: Nassis George P. , Figueiredo Pedro
Published: November 2024

The aim of the present study was to examine: 1) the coexistence of excessive body
weight and low cardiorespiratory fitness (CRF), at a level to be considered
unhealthy, and 2) the stability (tracking) of this profile. 1754 European boys,
aged 8- to 14-years old, were tested for CRF and based on international cut
points were classified as having healthy (H) or unhealthy (UN) CRF. Based on BMI
they were classified as having normal weight (N), or overweight or obesity (OO).
Chi-square was performed with four groups (i.e. N/H, N/UN, OO/H and OO/UN) and
the odds ratios were calculated (cross-sectional analysis). A sub-group of 353
boys were followed for an average of 3.79±0.83 years (range: 2.97− 6.06;
longitudinal analysis). The odds that a boy was with OO/UN profile compared to
the normal body weight category ranged from 2.67 (13-years old) to 6.74 (9-years
old). 56.6% of the participants remained in the same category, whereas 28.0% of
them had ≥1 change in category to worst in the second assessment (Cohen Kappa=
0.557, p<0.001; substantial agreement). The odds ratios of having boys with
unhealthy profile of combined excessive body weight and low CRF ranged from
medium to large. The stability of unhealthy profile was substantial.
Extracts of Drynariae Rhizoma Promote Bone Formation in OVX Rats through Modulating the Gut Microbiota
Authors: Lin Qing , Ouyang Xinchen , Pan Qi , Huang Jiajia , Zhang Zhifen , Yang Yumei , Wang Haoyu , Yang Li , Zhu Xiaofeng , Li Xiaoyun , Zhang Ronghua
Published: November 2024

Drynariae Rhizoma has been commonly used as a preventive and therapeutic agent for bone diseases. However, its pharmacological mechanisms have not been fully elucidated. Here, we aimed to investigate the effects of Drynariae Rhizoma in a bilateral ovariectomized rat model and explore the correlation with gut microbiome. We established an ovariectomized rat model, which we treated with different doses of Drynariae Rhizoma (Drynariae Rhizoma-Low, 0.27 g/kg/day; Drynariae Rhizoma-Middle, 0.81 g/kg/day; Drynariae Rhizoma-High, 2.43 g/kg/day) through intragastric administration for 12 weeks. Results showed that Drynariae Rhizoma alleviated body weight, moderated bone microstructure, and promoted the expression of bone formation-related factors in ovariectomized rats, in which Drynariae Rhizoma-High showed the most significant effects among the three doses. Furthermore, the effects of Drynariae Rhizoma on promoting bone formation were correlated to the changes in microbial
richness and the restorations of several genera, among which Ruminiclostridium and Ruminococcaceae_UCG_007 were positively correlated with the bone formation-related factors, and both were enriched in the Drynariae Rhizoma-High group as biomarkers. Moreover, CMP-legionaminate biosynthesis I might be a crucial pathway of Drynariae Rhizoma to regulate gut microbiota. The content of serum short-chain fatty acids in the ovariectomized rats were regulated by Drynariae Rhizoma. Our results demonstrate that Drynariae Rhizoma promotes bone formation in ovariectomized rats, and is related to the regulation of the gut microbiota structure.
Mohs Micrographic Surgery: A Brief Overview
Authors: Gamret A. Caresse , Roberts Jared E. , Srivastava Divya , Nijhawan Rajiv I.
Published: November 2024

Mohs micrographic surgery (MMS) is a tissue-sparing skin cancer resection technique that involves 100% margin analysis. This procedure is performed in the outpatient setting under local anesthesia by dermatologic surgeons who act as both the surgeon and the pathologist. The technique allows for prompt reconstruction immediately after cancer clearance and offers the highest cure rate for many skin malignancies, including basal and squamous cell carcinoma, as well as more rare tumors. Mohs surgery effectively ensures cancer clearance while minimizing defect size and optimizing cosmetic and functional outcomes for patients. Herein we will discuss the evolution, procedure, and indications of MMS.
Facial Reconstruction: The Nuances of Managing Undesirable Results
Authors: McAllister Lauren , Thornton James F.
Published: November 2024

Given the visibility of the face and the importance of its cosmesis, undesirable results following facial reconstruction present significant challenges for both the patient and the surgeon. Intraoperative measures and postoperative management can ameliorate some unfavorable outcomes, but others may require more extensive intervention. Approaching undesirable results with a frank assessment followed by shared decision-making not only improves outcomes but is also essential for patient satisfaction.
Impact craters reveal granular behavior of regoliths
Authors: Johnson-Groh Mara
Published: November 2024

Impacts were found to be more substantial on lunar and Martian soils compared to terrestrial ones.
A refined method for characterizing afterpulse probability in single-photon avalanche diodes
Authors: Dejen B. , Vaquero-Stainer A. , Santana T. S. , Arabskyj L. , Dolan P. R. , Chunnilall C. J.
Published: November 2024

Single-photon avalanche diodes (SPADs) are critical components in low-light-level sensing and photonic quantum information applications. For these, it is often necessary that a full characterization of the SPAD is performed, for which a key metric is the afterpulse probability. This study provides a detailed comparison of the common synchronized and non-synchronized methods used to measure afterpulse probability. Measurements on a single SPAD reveal inconsistencies between the afterpulse probabilities obtained by the two methods. By re-deriving the equations from first principles, the discrepancy is traced to the analysis approach for the non-synchronized experiment. An improved analysis approach is presented, leading to better agreement between the non-synchronized and synchronized methods. The study also provides guidance on the experimental conditions required for the valid application of both methods, along with a detailed analysis of the limitations of the non-synchronized method under high photon flux. These findings offer a more accurate approach for characterizing afterpulse probability and for reconciling the results of two methods, which enables better quantification of SPAD performance.
Coarse-grained polarizable soft solvent models, with applications in dissipative particle dynamics
Authors: Chiacchiera Silvia , Warren Patrick B. , Masters Andrew J. , Seaton Michael A.
Published: November 2024

We critically examine a broad class of explicitly polarizable soft solvent models aimed at applications in dissipative particle dynamics. We obtain the dielectric permittivity using the fluctuating box dipole method in linear response theory and verify the models in relation to several test cases, including demonstrating ion desorption from an oil–water interface due to image charge effects. We additionally compute the Kirkwood factor and find that it uniformly lies in the range gK≃0.7–0.8, indicating that dipole–dipole correlations are not negligible in these models. This is supported by the measurements of dipole–dipole correlation functions. As a consequence, Onsager theory over-predicts the dielectric permittivity by 20%–30%. The mean square molecular dipole moment can be accurately estimated with a first-order Wertheim perturbation theory.
Realizable seismic cloak via polar metamaterials
Authors: Zhang Yuexin , Tan Jingmei , Shen Yawen , Yang Hongwu , Peng Pai , Liu Fengming , Du Qiujiao
Published: November 2024

Transformation elastodynamics can be used to redirect incident waves to mitigate harmful vibrations in the target region. Under the specific Brun–Guenneau–Movchan gauge, the elastic tensor of the transformed domain lacks minor symmetry. Here, we propose a physically realizable seismic cloak composed of lattice-based polar metamaterials capable of exhibiting asymmetric stresses. Both static and dynamic simulations validate the cloaking performance. A metric is calculated to quantify the protective effects, and results demonstrate satisfactory cloaking and aseismic protection across a wide frequency band.
Dynamic instabilities and turbulence of merged rotating Bose–Einstein condensates
Authors: Sivakumar Anirudh , Mishra Pankaj Kumar , Hujeirat Ahmad A. , Muruganandam Paulsamy
Published: November 2024

We present the simulation results of merging harmonically confined rotating Bose–Einstein condensates in two dimensions. Merging of the condensate is triggered by positioning the rotation axis at the trap minima and moving both condensates toward each other while slowly ramping their rotation frequency. We analyze the dynamics of the merged condensate by letting them evolve under a single harmonic trap. We systematically investigate the formation of solitonic and vortex structures in the final, unified condensate, considering both nonrotating and rotating initial states. In both cases, merging leads to the formation of solitons that decay into vortex pairs through snake instability, and subsequently, these pairs annihilate. Soliton formation and decay-induced phase excitations generate sound waves, more pronounced when the merging time is short. We witness no sound wave generation at sufficiently longer merging times that finally leads to the condensate reaching its ground state. With rotation, we notice off-axis merging (where the rotation axes are not aligned), leading to the distortion and weakening of soliton formation. The incompressible kinetic energy spectrum exhibits a Kolmogorov-like cascade [E(k)∼k−5/3] in the initial stage for merging condensates rotating above a critical frequency and a Vinen-like cascade [E(k)∼k−1] at a later time for all cases. Our findings hold potential significance for atomic interferometry, continuous atomic lasers, and quantum sensing applications.
A mathematical model for predicting liquid release and spraying characteristics of fixed-wing airtankers
Authors: Sun Haoran , Wu Chengyun , Wu Yang , Hu Renyu , Wang Yanmeng , Sun Jingnan , Duan Zhongdi
Published: November 2024

Airtankers are one of the most effective methods for combating forest fires. To investigate the firefighting performance of fixed-wing airtankers, a mathematical model for predicting the liquid release and spraying characteristics of aerial firefighting aircraft is proposed in this study. The present model utilizes nozzle flow equations to describe liquid discharge and integrates equations for Kelvin–Helmholtz and Rayleigh–Taylor instabilities for primary breakup, along with a simplified diffusion sub-model for droplet spreading. A tailor-made decoupled algorithm is developed to solve the model. The model is validated through drop tests with the DC-10 aircraft and experiments in the low-speed wind tunnel, demonstrating its accuracy in capturing primary spray pattern features. The influences of dropping conditions on firefighting efficiency are further investigated, including drop height, ground speed, discharge mass flow rate, and crosswind velocity. The computation results indicate that increasing drop height decreases core coverage level with minimal impact on effective pattern width, while higher ground speeds reduce coverage level and pattern width; increased discharge mass flow rate enhances coverage level and effective width but shortens retardant line length; crosswind effects introduce asymmetry in the pattern profile and affect coverage thickness.
Geometric flow control in lateral flow assays: Macroscopic two-phase modeling
Authors: Jamshidi Farshid , Bayat Siamak , Ernst Andrea , Nestler Britta
Published: November 2024

Lateral flow assays (LFAs) are widely employed in a diverse range of applications, including clinical diagnostics, pharmaceutical research, forensics, biotechnology, agriculture, food safety, and environmental analysis. A pivotal component of LFAs is the porous polymeric membrane, which facilitates the capillary-driven movement of fluids, known as “imbibition,” in which a wetting fluid displaces a non-wetting fluid within the pore space of the membrane. This study presents a multi-scale modeling framework designed to investigate the imbibition process within LFAs. The framework integrates microscopic membrane characteristics into a macroscopic two-phase flow model, allowing the simulation of imbibition in membranes with different micro-scale properties and macro-scale profiles. The validity of the model was established through comparative analysis with documented case studies, a macro-scale single-phase flow model, and experimental observations, demonstrating its accuracy in simulating the imbibition process. The study also examines imbibition in various geometric configurations, including bifurcated (Y-shaped) and multi-branch geometries commonly found in multiplexed LFAs. The influence of geometric features such as length ratio, width ratio, branching angle, bifurcation point location, and asymmetry on fluid transport is investigated. Results indicate that membranes with larger branching angles exhibit slower imbibition. In addition, the influence of membrane type on macroscopic flow patterns is evaluated, showing that membranes with lower permeability require longer imbibition times. The insights gained from this research support a data-driven strategy for manipulating wetting behavior within LFAs. This approach can be leveraged to optimize the performance of LFAs and increase their effectiveness in various applications.
Characterization of droplet clusters in a turbulent multiphase gas cloud using a model cough simulator
Authors: Vishwakarma Ashish Kumar , Sahu Srikrishna
Published: November 2024

This study aims to investigate the transport of droplets ejected from an artificial cough simulator, which releases a turbulent puff of droplets into the surrounding air, closely resembling the human coughing process. The focus is on understanding droplet clustering within the multiphase gas cloud across various operating conditions that emulate the wide variation in the spray characteristics in actual human subjects owing to infection severity, age, and gender. Time-resolved particle image velocimetry (PIV) technique was employed to measure the velocity of both droplet and gas phases. It also facilitates the identification and characterization of droplet clusters through Voronoi analysis of the PIV images. The area and length scale of individual droplet clusters were measured, and the degree of droplet clustering was quantified using the clustering index and relative droplet number density within the clusters. Additionally, the interferometric laser imaging for droplet sizing technique was utilized for planar measurement of individual droplet sizes. The range of Stokes number indicated partial to poor response of the droplets to the turbulent eddies. The results reported, for the first time, the presence of droplet clusters in the simulated coughing process. The wide spectrum of cluster size and self-similar evolution of droplet clusters unveil a multi-scale clustering phenomenon, shedding light on the intricate dynamics of the respiratory droplet dispersion process. The study comprehensively investigates the role of injection pressure on droplet clustering and the spatial development of the clusters, revealing some interesting findings, which are discussed.
Analytical study of rotating detonation and engine operating conditions
Authors: Kanda Takeshi , Inagaki Hidetaka
Published: November 2024

In this paper, the mechanism of rotating detonation is analytically discussed using a two-dimensional sheet model. Two ratios are employed in this discussion: the ratio of the sonic point width to the detonation front width, and the ratio of the effective mixture injection area to the injection area. In the rotating detonation, the unconfined boundary can increase the width at the sonic point and decrease the detonation wave speed. Although the high detonation pressure hinders mixture injection, effectively preventing some injectors from functioning, the high pressure acting on the injection end wall produces thrust. Mass, momentum, energy, and angular momentum conservations are used to determine these ratios. The calculated results are in reasonable agreement with past experimental and numerical findings. The present model succeeds to clarify the features, parameter relationships, and overall mechanism of the rotating detonation analytically and to specify flow field of the rotating detonation under given boundary conditions, e.g., the velocity deficit and the effective injection area ratio. The specific impulse of a rotating detonation engine was lower than that of an ordinary rocket engine due to the lower combustion gas pressure when the combustion gas expanded to 1 atm. The thrust coefficient and the specific impulse of an air-breathing rotating detonation engine were shown to be lower than those of a ramjet engine, respectively, primarily because of the smaller airflow rate into the engine.
Acoustic non-Hermitian Dirac states tuned by flexible designed gain and loss
Authors: Peng Mian , Wu Chaohua , Cui Zhenxing , Zhang Xuewei , Wei Qiang , Yan Mou , Chen Gang
Published: November 2024

Non-Hermitian Dirac point plays an important role in topological transition as their Hermitian counterpart and connect non-Hermitian physics with band topology. Instead of being exceptional point or exceptional ring, we here reveal that the Dirac points can be survived in the presence of gain and loss obeying anti-parity-time symmetry based on the two-dimensional inclined Su–Schrieffer–Heeger model. Particularly, such non-Hermitian parameters enable the engineering of non-Hermitian Dirac states, including shift of the Dirac points and topological transition from Dirac semimetal to weak topological insulator. We experimentally demonstrate these non-Hermitian Dirac states in acoustic crystal, where the gain and loss are, respectively, controlled by the active acoustic components and absorbing materials. Through varying the strength of gain and loss, the shifting and opening of the Dirac points, together with topological edge states, are observed. Our system serves as an ideal and highly tunable platform for exploring the non-Hermitian topological physics and has potential applications in designing acoustic devices.
Impact of continuously extending/retracting wall on Mack-mode evolution in hypersonic boundary layers
Authors: Jiang Genrui , Dong Ming , Zhao Lei
Published: November 2024

Structural morphing is regarded as a potential solution for future space transportation systems, necessitating aircraft capable of extensive altitude ranges, wide speed ranges, and multi-regime operations. The investigation of laminar-turbulent transition incorporating morphing effects aims to compensate for the lack of physical mechanisms in aircraft designs. This paper particularly focuses on the impact of a continuously extending or retracting wall in the chordwise direction on the evolution of inviscid Mack modes in a Mach 5.92 hypersonic boundary layer. Using the high-Reynolds-number asymptotic technique, a model is developed to quantify the morphing effect by an amplification factor, which includes both the scattering effect at the rigid-morphing junction and the successive modification of the Mack growth rate by the morphing velocity in the downstream region. Such a model enables us to conduct a comprehensive investigation across a wide parameter space defined by morphing speed and flow parameters. A critical frequency is identified near the most unstable second-mode frequency. For an extending wall, the oncoming Mack modes are suppressed for frequencies above this critical frequency and enhanced for frequencies below it. Conversely, the retracting-wall effect exhibits an inverse impact on the Mack modes. To validate the accuracy of the asymptotic predictions, the harmonic linearized Navier–Stokes calculations are performed, resulting in favorable agreements. This research sheds light on the complex interplay between wall morphing and the Mack-mode evolution, offering informative contributions to the understanding of the aerodynamic behaviors in hypersonic boundary layers.
Formylation facilitates the reduction of oxidized initiator methionines
Authors: Tan Ruiyue , Hoare Margaret , Bellomio Philip , Broas Sarah , Camacho Konttessa , Swovick Kyle , Welle Kevin A. , Hryhorenko Jennifer R. , Ghaemmaghami Sina
Published: November 2024

Within a cell, protein-bound methionines can be chemically or enzymatically oxidized, and subsequently reduced by methionine sulfoxide reductases (Msrs). Methionine oxidation can result in structural damage or be the basis of functional regulation of enzymes. In addition to participating in redox reactions, methionines play an important role as the initiator residue of translated proteins where they are commonly modified at their α-amine group by formylation or acetylation. Here, we investigated how formylation and acetylation of initiator methionines impact their propensity for oxidation and reduction. We show that in vitro, N-terminal methionine residues are particularly prone to chemical oxidation and that their modification by formylation or acetylation greatly enhances their subsequent enzymatic reduction by MsrA and MsrB. Concordantly, in vivo ablation of methionyl-tRNA formyltransferase (MTF) in

Escherichia coli

increases the prevalence of oxidized methionines within synthesized proteins. We show that oxidation of formylated initiator methionines is detrimental in part because it obstructs their ensuing deformylation by peptide deformylase (PDF) and hydrolysis by methionyl aminopeptidase (MAP). Thus, by facilitating their reduction, formylation mitigates the misprocessing of oxidized initiator methionines.
Deciphering the RNA-binding protein network during endosomal mRNA transport
Authors: Devan Senthil-Kumar , Shanmugasundaram Sainath , Müntjes Kira , Postma Johannes , Smits Sander H. J. , Altegoer Florian , Feldbrügge Michael
Published: November 2024

Microtubule-dependent endosomal transport is crucial for polar growth, ensuring the precise distribution of cellular cargos such as proteins and mRNAs. However, the molecular mechanism linking mRNAs to the endosomal surface remains poorly understood. Here, we present a structural analysis of the key RNA-binding protein Rrm4 from
Ustilago maydis
. Our findings reveal a different type of MademoiseLLE domain (MLLE) featuring a seven-helical bundle that provides a distinct binding interface. A comparative analysis with the canonical MademoiseLLE domain of the poly(A)-binding protein Pab1 disclosed unique characteristics of both domains. Deciphering the MLLE binding code enabled prediction and verification of previously unknown Rrm4 interactors containing short linear motifs. Importantly, we demonstrated that the human MLLE domains, such as those of PABPC1 and UBR5, employed a similar principle to distinguish among interaction partners. Thus, our study provides detailed mechanistic insights into how structural variations in the widely distributed MLLE domain facilitate mRNA attachment during endosomal transport.