bluuebunny/crossref_metadata_2025 huggingface dataset:
Erhebung der Versorgungsstrukturen an Transplantationszentren
für Patient*innen mit äthyltoxischer Leberzirrhose vor
einer Lebertransplantation. Eine qualitative Befragung von
Behandler*innen.
Authors: Binder Annette , Fenchel Julia , Lang Immanuel , Batra Anil
Published: July 2023

Ziel der Studie Ziel dieser Untersuchung war es, die derzeitigen
Versorgungs- und Kontrollstrukturen für Patient*innen mit
äthyltoxischer Leberzirrhose in der Vorbereitung auf eine
Lebertransplantation (LTX) an deutschen Transplantationszentren zu erfassen. Es
sollten zudem die damit einhergehenden Barrieren sowie die Sicht der
Behandler*innen auf Verbesserungsmöglichkeiten für die
Versorgung der Patient*innengruppe analysiert werden.

Methodik In einem explorativen, deskriptiven, qualitativen Design wurden
11 Interviews mit Behandler*innen aus 10 der 22 deutschen LTX-Zentren
geführt und inhaltsanalytisch ausgewertet.

Ergebnisse Es zeigten sich deutliche Unterschiede in den Versorgungs- und
Kontrollstrukturen der einzelnen Zentren. In das Behandlungskonzept integrierte
suchttherapeutische Angebote gab es nicht an allen Zentren. Strukturelle
Barrieren entstanden durch eine unzureichende Finanzierung und personelle
Ausstattung. Behandler*innen wünschten sich erweiterte
Behandlungsangebote sowie vereinheitlichte Behandlungskonzepte.

Schlussfolgerungen Es zeigte sich Handlungsbedarf sowohl im Bereich der
Strukturen der einzelnen LTX-Zentren als auch übergreifend auf
Systemebene. Diese Ergebnisse könnten unter Berücksichtigung
aktueller suchtmedizinischer Erkenntnisse als Grundlage zur Entwicklung von
Behandlungskonzepten und -empfehlungen zur Optimierung der Versorgung vor LTX
dienen.
Arbeitszeit von Ärztinnen und Ärzten in Deutschland:
Ergebnisse des Mikrozensus mit Fokus auf Niedergelassene
Authors: Kögel Andreas , Lauerer Michael , Zank Daniel
Published: July 2023

Ärzt:innen in eigener Praxis gelten als Berufsgruppe mit hoher
Arbeitsbelastung. Da Befunde zur Arbeitszeit lückenhaft sind, wurden
Angaben im Mikrozensus 2017 zur „normalen“ Arbeitszeit und zu
Präferenzen ausgewertet. Freiberufliche Ärzt:innen berichten bei
Vollzeittätigkeit im Schnitt eine Arbeitszeit von 48,8 h pro
Woche, abhängig Beschäftigte 46,2 h. Bei
Teilzeittätigkeit geben abhängig Beschäftigte ca. 4
Stunden mehr an als Freiberufler. Männer berichten bei
Vollzeittätigkeit etwa 4 Stunden mehr als Frauen, bei Teilzeit 5 Stunden
weniger. Der Teilzeitanteil ist bei Ärztinnen höher als bei
Ärzten (28% vs. 10%). Die spezifische Analyse
für freiberuflich Tätige zeigt ebenfalls eine umgekehrte
Diskrepanz: Bei Teilzeit arbeiten Ärztinnen 4 h mehr als
Ärzte, bei Vollzeit arbeiten Ärzte 4 h mehr als
Ärztinnen. Niedergelassene/Freiberufliche arbeiten in Teilzeit
weniger als Angestellte. Auch hier liegt die Quote bei Ärztinnen
höher (19,5% vs. 10,6%). Insgesamt arbeiten 14%
in Teilzeit (knapp 20 h pro Woche), 86% Vollzeit (knapp
49 h). Zahnärzt:innen berichten etwas niedrigere Arbeitszeiten,
Allgemein- und Fachärzt:innen liegen mit 45 Stunden ca. gleichauf.
Dieser Unterschied geht auf Differenzen bei der Vollzeitarbeit zurück,
die bei Allgemein- und Fachärzt:innen etwa 50, bei
Zahnärzt:innen 46 Stunden beträgt. Demgegenüber arbeiten
Zahnärzt:innen in Teilzeit länger (24 vs. 18 Stunden). Nur
wenige, insb. in Teilzeit arbeitende Ärzt:innen (ca. 6,5%) geben
an, mehr arbeiten zu wollen. Als Grund für Teilzeitarbeit nennen Frauen
mehrheitlich familiäre Verpflichtungen (68%), Männer
meist „sonstige“ Gründe (76%) und seltener
Kinderbetreuung oder persönliche/familiäre
Verpflichtungen (15%). Insgesamt 13% der Vollzeitarbeitenden
wünschen weniger Arbeitsstunden – Frauen etwas häufiger.
Die vorliegende Analyse ergänzt Quellen wie das Zi-Praxis-Panel. Auf der
Gesamtebene liegt der Durchschnitt im Mikrozensus 5 Stunden unter dem des ZiPP
(50 h/Woche). Den aus der Methodenlehre bekannten
Einschränkungen für Befragungsdaten steht die hohe
Stichprobenqualität gegenüber.
Primary Anterior Cruciate Ligament Reconstruction with Suture Tape Augmentation: A Case Series of 252 Patients
Authors: Daniel Adam V. , Sheth Chirag D. , Shubert Daniel J. , Smith Patrick A.
Published: July 2023

Anterior cruciate ligament reconstruction (ACLR) using suture tape augmentation to internally brace is a relatively new technique. The primary goal of this study was to prospectively collect patient-reported outcomes (PROs) and surgical history from patients who underwent primary ACLR with internal bracing to determine if internal bracing resulted in a low graft failure rate while maintaining acceptable PROs. A total of 252 patients with a mean age of 23.6 years (95% confidence interval [CI]: 22.1–25.1) and a mean follow-up of 37.9 months (95% CI: 35.8–40.0) were included in this study. Patients who underwent primary ACLR with internal brace augmentation between July 12, 2016 and July 31, 2021 were eligible. A total of 222 patients were contacted via telephone and administered the visual analog scale (VAS), the single assessment numeric evaluation (SANE), the Lysholm knee score scale, and, if applicable, the short version ACL return to sport after injury (SV-ACL-RSI) survey. Additionally, patients were asked to give an updated orthopaedic history. Thirty additional patients were included from either our institution's registry or by completing their surveys in-office or by e-mail. The minimal clinically important difference (MCID) and patient-acceptable symptom states (PASS) were calculated based on our patient population and applied to each individual patient. The patients' electronic health record (EHR) was searched for pre- and postoperative clinical data including KT-1000 arthrometer measurements. Two patients (0.8%) had subsequent graft failures and one patient (0.4%) required a revision surgery. MCID was achieved in 242 patients (96.0%) for the Lysholm, 227 patients (90.1%) for the SANE, and 146 patients (57.9%) for the VAS. PASS was achieved in 214 patients (84.9%) for the Lysholm, 198 patients (78.6%) for the SANE, and 199 (80.0%) patients for the VAS, postoperatively. Of note, 65 patients (25.8%) exceeded the PASS threshold for the VAS preoperatively. A total of 127 patients (84.4%) met the cutoff of ≥60/100 for the SV-ACL-RSI survey postoperatively. Postoperative KT-1000 measurements showed near-identical side-to-side differences at both the 13.6-kg pull and manual maximum pull. When stratifying patients based on age at the time of surgery, it was noted that patients younger than 25 years had significantly higher SANE scores (91.6 [95% CI: 90.2–92.9] vs. 82.6 [95% CI: 79.0–86.2]; p < 0.0001) and lower VAS pain scores (0.7 [95% CI: 0.5–0.8] vs. 1.2 [95% CI: 0.8–1.5]; p = 0.004). Primary ACLR with internal bracing led to acceptable patient outcomes and a graft failure rate of less than 1%.

Level of Evidence: case series, IV
Basic Concepts and Insights into Aortopulmonary Collateral Arteries in Congenital Heart Diseases
Authors: Sharma Arun , Vadher Akash , Shaw Manish , Malhi Amarinder S. , Kumar Sanjeev , Singhal Manphool
Published: July 2023

Aortopulmonary collateral arteries are persistent embryological vessels supplying lung parenchyma in various cardiopulmonary diseases with underlying pulmonary hypoperfusion. Their identification and mapping are important because of associated clinical implications and tendency to affect the surgical outcome. This article describes the embryological development and clinical relevance of aortopulmonary collaterals in various congenital cardiopulmonary conditions, along with the significance for treatment planning. Roles, strength, and shortcomings of the various imaging options and image-guided interventions are discussed, with a focus on presurgical planning and preparation, as well as postsurgical management.
Modification of transformer coupled permeameter for frequency extension
Authors: Tamaru S.
Published: July 2023

A broadband and high-sensitivity permeability measurement system that covers 10 MHz–20 GHz was previously developed and named the transformer coupled permeameter (TC-Perm). This paper describes the modifications of the TC-Perm system to further extend the operation frequency range on both the high and low frequency sides. In the previous system, the high frequency limit was set by a large notch appearing at around 22 GHz, which was considered to be caused by the excitation of two unwanted modes. In the new system, the jig design was modified to have a back ground plane and vias to suppress these unwanted modes, which resulted in a clean transmission characteristic over the entire frequency range up to 44 GHz. The low frequency limit is determined by the noise figure (NF) of the vector network analyzer input, which was measured to be ∼35 dB in the previous system configuration. The new system employed a low noise amplifier and analog switches to improve the NF to be 2.7 dB below 100 MHz. As a result of these modifications, the operation frequency range of the new TC-Perm system was extended to cover 1 MHz–44 GHz, which is sufficient for characterizing magnetic materials used in noise suppression sheets targeting fifth-generation millimeter-wave (5G mmWave) wireless communication.
Inkjet printing on hydrophobic surfaces: Controlled pattern formation using sequential drying
Authors: Naderi Paria , Sheuten Benjamin Raskin , Amirfazli Alidad , Grau Gerd
Published: July 2023

Inkjet-printed micro-patterns on hydrophobic surfaces have promising applications in the fabrication of microscale devices such as organic thin-film transistors. The low wettability of the surface prevents the inkjet-printed droplets from spreading, connecting to each other, and forming a pattern. Consequently, it is challenging to form micro-patterns on surfaces with low wettability. Here, we propose a sequential printing and drying method to form micro-patterns and control their shape. The first set of droplets is inkjet-printed at a certain spacing and dried. The second set of droplets is printed between these dry anchors on the surface with low wettability. As a result, a stable bridge on the surface with low wettability forms. This printing method is extended to more complicated shapes such as triangles. By implementing an energy minimization technique, a simple model was devised to predict the shape of the inkjet-printed micro-patterns while confirming that their equilibrium shape is mainly governed by surface tension forces. The gradient descent method was utilized with parametric boundaries to emulate droplet pinning and wettability of the anchors and to prevent convergence issues from occurring in the simulations. Finally, the energy minimization based simulations were used to predict the required ink to produce dry lines and triangles with smooth edges.
Non-local dielectric effects in nanoscience
Authors: Raja Archana , Brus Louis E.
Published: July 2023

The physical properties of charges and excitations in nanoscale materials are influenced both by the dielectric properties of the material itself and the surrounding environment. This non-local dielectric effect was first discussed in the context of molecules in solvents over a century ago. In this perspective, we discuss non-local dielectric effects in zero-dimensional, one-dimensional, and two-dimensional nanoscale systems.
Dual-polarization quantum-enhanced stimulated Raman scattering microscopy
Authors: Xu Zicong , Oguchi Kenichi , Nitanai Sho , Taguchi Yoshitaka , Sano Yuki , Ozeki Yasuyuki
Published: July 2023

In this paper, we propose an approach for implementing quantum-enhanced stimulated Raman scattering (QESRS) microscopy using a dual-polarization scheme. This approach has advantages for high-power operation and enables ultrasensitive Raman detection of molecular vibrational mode symmetry. To demonstrate the feasibility and effectiveness of our technique, we present both the theoretical framework and experimental results of dual-polarization QESRS. Our technique resulted in a noticeable reduction of noise on both parallel and orthogonal QESRS spectra as well as on the depolarization ratio spectra. These results validate the potential of our approach for achieving high-speed QESRS imaging with sub-shot-noise sensitivity.
Intercomparison of hydrostatic and nonhydrostatic modeling for tsunami inundation mapping
Authors: Bai Yefei , Yamazaki Yoshiki , Cheung Kwok Fai
Published: July 2023

Nonhydrostatic modeling has emerged as an effective tool for seismological and tsunami research for over a decade, but its general application in hazard mapping and engineering design remains a topic of discussion. The approach incorporates the depth-averaged vertical velocity and nonhydrostatic pressure in the nonlinear shallow-water equations that provide a Poisson-type equation via the conservation of mass for quasi-three-dimensional flows. After the 2011 Tohoku tsunami, the State of Hawaii augmented the existing inundation maps to account for probable maximum tsunamis from Mw 9.3 and 9.6 Aleutian earthquakes. The use of both hydrostatic and nonhydrostatic modeling with a common set of telescopic computational grids covering 1330 km of shorelines facilitates a thorough intercomparison under distinct extreme events over a range of tropical island terrain and bathymetry. Including vertical flow dynamics can enhance the formation of a slowly attenuating trough behind the leading crest across the ocean as well as drawdown of receding water over steep nearshore slopes. The nonhydrostatic approach consistently gives lower predictions of the offshore tsunami amplitude due to frequency dispersion but can produce more severe coastal surges from resonance of the leading crest and trough over insular slopes as well as trapping of tsunami waves by wide shelves. Despite the potential for underestimating coastal surges, the lack of vertical inertia in hydrostatic models can result in substantially larger runup over steep terrain. The tsunami processes leading to inundation are complex with a strong dependence on the waveform and topography that can be well elucidated by the nonhydrostatic approach.
Temperature effects in plasma-based positron acceleration schemes using electron filaments
Authors: Diederichs S. , Benedetti C. , Esarey E. , Thévenet M. , Sinn A. , Osterhoff J. , Schroeder C. B.
Published: July 2023

Preserving the quality of a positron beam in a plasma-based accelerator, where a wakefield suitable for positron transport and acceleration is generated by means of an electron filament, is challenging. This is due to the nature of the wakefields, characterized by focusing fields that vary nonlinearly in the transverse direction, and by accelerating fields that are non-uniform. These fields also change slice-by-slice along the beam. Maintaining a high beam quality is pivotal for application of positron beams in a plasma-based collider. In this paper, we show that an initial background plasma temperature can help mitigate the positron beam quality degradation in plasma-based accelerators that rely on electron filaments. We show that temperature effects broaden the electron filament and smooth radially both the non-linear transverse and the non-uniform longitudinal wakefields. Using warm plasmas opens up new possibilities to improve beam quality in several plasma-based positron acceleration concepts.
Asymmetric branch selection and splitting of droplets in T-junction microchannels
Authors: Pang Yan , Jiao Shaojie , Lu Yao , Yang Qingshan , Wang Xiang , Liu Zhaomiao
Published: July 2023

The droplet motion in the T-junction is the basis for the design of droplet microfluidic chip. This paper investigates droplet motion in T-junction microchannels based on experiments and simulations to analyze the droplet motion mode and its effect on the downstream flow of the channel. The droplet motion can be divided into three modes, including flowing into the downstream main channel, flowing into the side branch, and splitting, whose transitions depend on the inlet flow ratio and droplet length. The critical droplet length, to determine whether the droplet is complete through the junction, follows a non-linear relationship of capillary number with the coefficient of 0.3–0.5, which is influenced by the liquid viscosity ratio. It was found that the droplets can be divided into two kinds according to its length by l0 = 0.8wm, which have significantly different interfacial deformations and cause various fluctuations of the branch flow even under the same flow conditions.
Spin-phonon coupling in a double-stranded model of DNA
Authors: Peralta Mayra , Feijoo Steven , Varela Solmar , Gutierrez Rafael , Cuniberti Gianaurelio , Mujica Vladimiro , Medina Ernesto
Published: July 2023

We address the electron-spin-phonon coupling in an effective model Hamiltonian for DNA to assess its role in spin transfer involved in the Chiral-Induced Spin Selectivity (CISS) effect. The envelope function approach is used to describe semiclassical electron transfer in a tight-binding model of DNA at half filling in the presence of intrinsic spin–orbit coupling. Spin-phonon coupling arises from the orbital-configuration dependence of the spin–orbit interaction. We find spin-phonon coupling only for the acoustic modes, while the optical modes exhibit electron–phonon interaction without coupling to spin. We derive an effective Hamiltonian whose eigenstates carry spin currents that are protected by spin-inactive stretching optical modes. As optical phonons interact more strongly than acoustic phonons, side buckling and tilting optical base modes will be more strongly associated with decoherence, which allows for the two terminal spin filtering effects found in CISS.
Broadband directional thermal radiator with flexible intensity–directivity tunability in the whole visible spectrum
Authors: Wang Cun-Hai , Liu Ming-Xiang , Pan Chong-Chao , Jiang Ze-Yi
Published: July 2023

Controlling spectral and directional distributions of thermal radiation plays an important role in designing functional structures for thermal management. As a wideband phenomenon, thermal radiation is supposed to be manipulated within broad wave ranges for the case of practical thermal applications. However, currently, it is still challenging to constrain broadband radiation into wanted directions in a controllable manner. In this work, based on light-trapping effects mediated by periodic germanium strips on a silver substrate, we design a thermal radiator with broadband directional (BBD) emissivity in the whole visible spectrum. The radiator is free from intricate nanofabrication and can achieve low-dispersive directional emissivity within a continuous wave range of 0.4–0.8 μm. In addition, the proposed radiator exhibits flexible tunability on the BBD performance and emission intensity, making it an outstanding candidate for functional surfaces in thermal energy management.
Mid-infrared vortex array generation with a tunable singularity in an Er:YAP laser
Authors: Liu Jun , Gu Jie , Huang Lu , Zhang Chun Xiang , Bai Zhi Yong , Fan Dian Yuan
Published: July 2023

Optical vortex arrays are structured light fields with multiple phase singularities that have attracted considerable attention in recent years. Here, we demonstrate the direct generation of an optical vortex array with tunable singularity from a mid-infrared Er: yttrium aluminum perovskite laser under the annular-pumping regime. An axicon combined with a plano–convex lens is used to reshape the pumping beam into an annular one to match the different orders of the Laguerre–Gaussian mode. By adjusting the pump power and the lateral displacement of the gain medium, a tunable vortex array with one to four singularities is obtained in the ∼3-μm mid-infrared wavelength region. The lasing characteristics of the mid-infrared vortex arrays are evaluated and discussed. The experimental results can shed some light on the generation of mid-infrared optical vortex laser arrays and their applications.
Effects of hydroxyapatite nanoparticles on the vitrification of bovine metaphase II oocytes
Authors: Liu Yi-Heng , Wang Xiao-Jing , Liu Jia-Qi , Zhao Shi-Yu , Xu Zhi-Qian , Li Xiao-Xia , Li Ying-Hua , Yu Xue-Li
Published: July 2023

Context Although vitrification is commonly used for oocyte cryopreservation, the cryogenic damage results in poor developmental capacity of oocytes after freezing. Nano-cryopreservation is one of the new methods of vitrification developed in recent years. However, the effect of nano-cryopreservation on mature bovine oocytes remains to be elucidated. Aims This study aimed to verify the effect of using hydroxyapatite (HA) nanoparticles (NPs) on the vitrification of bovine metaphase II (MII)-stage oocytes. Methods Bovine MII-stage oocytes were exposed to different HA concentrations (0.01%, 0.05%, and 0.10%) in vitrification solution (VS). After IVF (in vitro fertilisation) and IVC (in vitro culture), the toxicity of HA was assessed by cleavage and blastocyst rates. A suitable concentration of HA nanoparticles was selected according to the results of the first experiment. and then vitrification-thawing was measured. The effect of HA on the developmental capacity of oocytes was assessed by oocyte cleavage rate and blastocyst rate. The mitochondrial membrane potential (MMP) and the intracellular reactive oxygen levels (ROS) of oocytes were measured by staining with a fluorescence probe (JC-1) and an ROS kit after nano-cryopreservation. Key results The addition of 0.05% HA to the VS did not affect the oocyte morphology; the proportion of oocytes developing with normal morphology was 96.72%. In contrast, this proportion it significantly decreased at a concentration of 0.1% HA in VS (91.69%; P < 0.05). The cleavage rates (56.95% vs 51.20%, 50.67%; P < 0.05) of bovine oocytes exposed to 0.05% HA were significantly higher than in the VS group and VS + 0.1% HA group. After the vitrification-thawing, the oocyte cleavage rates (41.07% vs 33.97%; P < 0.05) and blastocyst rates (12.35% vs 7.38%; P < 0.05) were significantly higher in the VS + 0.05% HA group compared to the VS group. At the 0.05% HA concentration, nano-cryopreserved oocytes had significantly higher MMP (1.35 ± 0.24) and significantly lower ROS (1.43 ± 0.05) than the VS group (P < 0.05, mean ± s.e.m.). Conclusions The addition of 0.05% HA-NPs in VS could promote bovine MII-stage oocytes’ developmental ability after vitrification. This effect may be caused partly by increased mitochondrial membrane activity and decreased ROS. Implications HA-NPs may be a new class of cryoprotective agent suitable as components for oocyte vitrification.
Fabrication of nickel-titanium-iron shape memory alloys by powder metallurgy route and analyses of their physical and mechanical behaviour
Authors: Parida Jagadish , Mishra Subash Chandra , Marupalli Bharat C. G. , Behera Ajit
Published: July 2023

In this research work, the effect of Fe additions on the phase evolution, microstructure, chemical composition, transformation behaviour and properties of Ni(50−X)Ti50FeX shape memory alloys has been investigated. The elemental Ti, Ni and Fe mixed powders are compacted at 600 MPa, followed by sintering at 1100°C for 4hr in an Ar atmosphere. Phase analysis and microstructural studies confirmed the presence of the NiTi phase besides other Ni-rich and Ti-rich phases. The 8at.-% Fe sample shows higher relative density, lower porosity, higher hardness, higher elastic modulus and higher wear resistance owing to the presence of a higher amount of secondary intermetallic phases compared to other composition samples. Interestingly, the 4at.-% Fe sample has a higher percentage of NiTi (B19’) phase and shows a better shape memory effect and elastic recovery than other composition samples. FESEM morphology of worn surface explained various wear mechanisms with respect to shape memory behaviour.
Evaluation of aging and degradation for silicone rubber composite insulator based on machine learning
Authors: Liu Yushun , Cheng Yang , Lv Li , Zeng Xin , Xia Lingzhi , Li Senlin , Liu Jing , Kong Fei , Shao Tao
Published: July 2023

Silicone rubbers (SIRs), as the main material of composite insulator sheds, have aging phenomenon for the long-term operation in the outdoor, which has an important impact on the performance degradation of composite insulator. Periodic examine and replacement of severely aged composite insulator is of great significance for the safe operation of power system. However, there is no clear standard to estimate the aging degree. In order to evaluate the degree of aging and degradation more accurately, the experimental test and analysis of the SIR sheds were carried out from three aspects: physical characteristics, chemical composition and electrical properties. The physical characteristic results show that the surface of the aging SIR will appear obvious holes and cracks, as well as hardening. Chemical composition results show that the internal composition of the continuous decomposition, while a large number of heavy metal elements accumulate in the pollution. The change of physical characteristics and chemical composition of SIR sheds may lead to the deterioration of electrical properties. According to the above results, the influence rule of measurement parameters and aging degree was obtained, and the key characteristic parameters of aging were summarized and extracted. Based on the characteristic parameters, a decision tree aging evaluation model is established for state evaluation. The accuracy of machine learning is 100% and 93.2% respectively. For the on-site application, early warning of moderately aged insulators and replacement of severely aged insulators are proposed in the on-site maintenance of SIR composite insulators.
Pseudo hard-sphere viscosities from equilibrium Molecular Dynamics
Authors: Nicasio-Collazo Luz Adriana , Ramírez-Medina Carlos Alberto , Torres-Carbajal Alexis
Published: July 2023

Transport coefficients like shear, bulk and longitudinal viscosities are sensitive to the intermolecular interaction potential and finite size effects when are numerically determined. For the hard-sphere (HS) fluid, such transport properties are determined almost exclusively with computer simulations. However, their systematic determination and analysis throughout shear stress correlation functions and the Green-Kubo formalism can not be done due to discontinuous nature of the interaction potential. Here, we use the pseudo hard-sphere (PHS) potential to determine pressure correlation functions as a function of volume fraction in order to compute mentioned viscosities. Simulation results are compared to available event-driven molecular dynamics of the HS fluid and also used to propose empirical corrections for the Chapman–Enskog zero density limit of shear viscosity. Moreover, we show that PHS potential is a reliable representation of the HS fluid and can be used to compute transport coefficients. The molecular simulation results of the present work are valuable for further exploration of HS-type fluids or extend the approach to compute transport properties of hard-colloid suspensions.
Combining kernel principal component analysis and spatial group-wise enhance convolutional neural network for fault recognition of rolling element bearings
Authors: Pan Huilin , Jiao Weidong , Yan Tianyu , Rehman Attiq Ur , Wan Anping , Yang Shixi
Published: July 2023

Data-driven deep learning methods have been widely used in the fault diagnosis of rolling bearings, while general network structures are complex with numerous parameters and computationally intensive calculations, leading to limited real-time performance and delayed fault detection. To address these challenges, this paper presents a novel hybrid framework, termed FKP-SGECNN, for efficient and accurate bearing fault identification. The proposed framework combines the strengths of kernel principal component analysis (KPCA), Fisher criterion, spatial group-wise enhance network (SGENet), and convolutional neural network. In the proposed framework, FKP incorporates Fisher criterion to optimize the kernel functions in KPCA, effectively reducing information redundancy in the input data. Furthermore, SGENet is integrated to streamline the network structure and enhance the model’s generalization capability, while maintaining high diagnostic accuracy. The performance of the hybrid framework implies a great potential, which was evaluated by several case studies using multi-class data of bearing faults.
A formalism for traceable dosimetry in superficial electronic brachytherapy (eBT)
Authors: de Prez Leon , Avilés Lucas Paz , Kok Elfried
Published: July 2023

Objective. Despite the number of treatments performed with electronic brachytherapy (eBT) there is no uniform methodology for reference dosimetry for international traceability to primary dosimetry standards in different eBT systems. The objective of this study is to propose a formalism for traceability reference dosimetry in superficial eBT, that is easy to apply in the clinic. This method was investigated for an Elekta Esteya with one applicator. Approach. The calibration x-ray spectrum at the primary standards dosimetry laboratory was matched to the measured eBT photon spectrum. Subsequently, two ionization chambers of different types were calibrated at the primary standard dosimetry laboratory (PSDL) in terms of air kerma against a primary standard. The chambers were used to measure ionization chamber reading ratios in-air at different distances from the applicator. Monte Carlo based air kerma ratios were calculated at different positions from the eBT applicator as well as backscatter factors in water and average mass energy absorption ratios in water and in air. Relative measurements with radiochromic films were performed in a water phantom to determine the ratio of absorbed dose to water, D

w
, at the surface to D

w
at 1 cm depth in water. These were compared with Monte Carlo calculations. Main results. Calculations and measurements were combined to estimate the D

w
at the surface and at 1 cm depth in water. Ionization chamber agreement of the surface dose was 1.7%, within an uncertainty of 6.8% (k = 2). They agreed with the manufacturer dosimetry within 1.8%, with an uncertainty of 5.0% (k = 2). The feasibility of the formalism and methodology for the Esteya system was demonstrated. Significance. This study proposes a method for harmonization of traceable reference dosimetry for eBT contact treatments which does not involve a detailed simulation of the ionization chamber. The method demonstrated feasibility for one eBT system using one surface applicator. In the future the method could be applied for different eBT systems.
Commissioning of a solid tank design for fan-beam optical CT based 3D radiation dosimetry
Authors: Ogilvy A , Collins S , Hilts M , Hare W , Jirasek A
Published: July 2023

Objective. Optical computed tomography (CT) is one of the leading modalities for imaging gel dosimeters used in the verification of complex radiotherapy treatments. In previous work, a novel fan-beam optical CT scanner design was proposed that could significantly reduce the volume of the refractive index baths that are commonly found in optical CT systems. Here, the proposed scanner has been manufactured and commissioned. Approach. Image reconstruction is performed through algebraic reconstruction technique and iterated using the fast iterative shrinkage-thresholding algorithm (FISTA) algorithm. Ray tracing for algebraic reconstruction was performed using an in-house developed ray tracing simulator. A set of Sylgard® 184 phantoms were created to commission spatial resolution, geometric deformity, contrast-to-noise ratio (CNR), and scan settings. Main Results. The scanner is capable of a 0.929 mm−1 spatial resolution, observed at 200 iterations, although the spatial resolution is highly dependent on the number of iterations. The geometric distortion, measured by scanning a needle phantom with the prototype scanner as well as a conventional x-ray CT was found to be within <0.25 mm. The CNR was found to peak between 65 and 190 occurring between 50 and 100 iterations and was highly dependent on the region chosen for background noise calculation. The proposed scanner is capable of scanning and reading out slices in less than 1 min per slice. Significance. This work displays the viability of a fan-beam optical CT scanner with minimal index matching using ray-traced algebraic reconstruction.
Multiscale self-calibrated pulmonary nodule detection network fusing dual attention mechanism
Authors: Zhu Yong , Xu LiXin , Liu Yusi , Guo PeiRen , Zhang JiYao
Published: July 2023

Objective. In this study, we propose a model called DEPMSCNet (a multiscale self-calibration network) that has a high sensitivity and low false positive rate for detecting pulmonary nodules. Approach. First, at the feature extraction stage, we propose to use the REPSA-MSC module instead of the traditional convolutional neural network. The module extracts multiscale information from the feature map based on the image pyramid strategy while introducing adaptive convolutional branches to detect contextual information at each position of the multiscale, thereby expanding the receptive field and improving sensitivity. At the same time, multiple branches are adaptively weighted by channel attention, and the weights of different branches are adjusted to better generate pixel-level attention. Secondly, the proposed DSAM (dual-path spatial attention module) operates at the information fusion stage. This module fully exploits the rich spatial information of CT scans, obtains receptive field information from two branches, combines low-level feature map information with high-level semantic information, and enhances location-related information to effectively improve specificity. Thirdly, the focal loss function is used to solve the problem of positive and negative sample imbalance. Main
results. The proposed model has been evaluated on the public lung nodule analysis (LUNA16) challenge dataset. The technique outperforms the most recent state-of-the-art detection algorithms in terms of sensitivity and specificity, obtaining a sensitivity of 0.988 and a competitive performance metric (CPM) of 0.963. Significance. Ablation experiments show that the two modules proposed in this paper effectively reduce false positives and improve sensitivity. This model effectively reduces the number of false positive nodules that doctors see on CT scans.
Analysing the effects of heating and gas puffing in Proto-MPEX helicon and auxiliary heated plasmas
*
Authors: Islam M S , Lore J D , Lau C , Rapp J
Published: July 2023

The Material Plasma Exposure Experiment (MPEX) is being constructed at Oak Ridge National Laboratory to investigate critical fusion reactor issues, such as plasma–material interactions (PMIs) under reactor-relevant conditions and time scales. The linear device Proto-MPEX was used as a test bed to address anticipated research and development issues associated with heating scenarios and establish the physics basis for MPEX. The SOLPS-ITER code suite has been applied to understand plasma and neutral transport in Proto-MPEX and to increase confidence in predictive simulations for MPEX. Coupling between COMSOL and SOLPS is performed to implement a 2D electron heating profile of the helicon source. The simulations show reasonable agreement with the experimental data for plasma with helicon and auxiliary electron cyclotron heating (ECH). Both Bohm and constant diffusion (D

⊥

: 0.5 m2 s−1 and

χ
⊥

: 1 m2 s−1) simulations show similar levels of agreement with respect to the sparse experimental data available, assuming a few per cent impurity concentration. ECH significantly increases the target electron temperature, however, the target electron density is reduced compared to helicon-only heated plasmas due to an increase in flow velocity and radial losses. The simulations show that further increasing the ECH power results in an increase in the target electron density due to increased recycling flux and ionization. The results indicate that ECH significantly enhances the target heat flux, with ECH power of 50 kW increasing the target heat flux from 0.4 to 17 MW m−2. It is found that a small amount of gas puffing (GP) near the target plate can further increase the target heat fluxes at the higher ECH power cases, but the target heat flux is reduced at higher GP conditions due to a significant reduction in electron temperature via radiation. ECH and GP scenarios can generate a higher target flux, facilitating improved PMI studies with more reactor-relevant plasma conditions.
Validity of Brink-Axel Hypothesis for calculations of allowed stellar weak rates of heavy nuclei
Authors: Farooq Fakeha , Nabi Jameel-Un , Shehzadi Ramoona
Published: July 2023

The knowledge of beta-decay transitional probabilities and Gamow-Teller (GT) strength functions from highly excited states of nuclides is of particular importance for applications to astrophysical network calculations of nucleosynthesis in explosive stellar events. These quantities are challenging to achieve from measurements or computations using various nuclear models. Due to unavailability of feasible alternatives, many theoretical studies often rely on the Brink-Axel (BA) hypothesis, that is, the response of strength functions depends merely on the transition energy of the parent nuclear ground state and is independent of the underlying details of the parent state, for the calculation of stellar rates. BA hypothesis has been used in many applications from nuclear structure determination to nucleosynthesis yield in the astrophysical matter. We explore here the the validity of BA hypothesis in the calculation of stellar beta-decay (BD) and electron capture (EC) weak rates of fp- and fpg-shell nuclides for GT transitions. Strength functions have been computed employing the fully microscopic proton-neutron QRPA (quasi-particle random-phase approximation) within a broad density, ρY
e
= (10-1011) [g cm−3], and temperature, T = (1−30) [GK], grid relevant to the pre-collapse astrophysical environment. Our work provides evidence that the use of the approximation based on the BA hypothesis does not lead to reliable calculations of excited states strength functions under extreme temperature-density conditions characteristic of presupernova and supernova evolution of massive stars. Weak rates obtained by incorporating the BA hypothesis in the calculation of strength functions substantially deviate from the rates based on the state-by-state microscopically calculated strength functions. Deviation in the two calculations becomes significant as early as neon burning phases of massive stars. The deviation in the calculation of BD rates is even more pronounced, reaching up to three orders of magnitude.
Switching motion analysis and synchronization control of a locally active memristive neuron model
Authors: Ren Yanlan , Zhang Li , An Xinlei , Zhang Jiangang
Published: July 2023

In this paper, a new four-dimensional HR neuron model is developed by means of injecting external alternating current and introducing a locally active memristor to simulate the induced current in the synapse. Firstly, the stableness of the equilibrium points under alternating current injection is analyzed by using Matlab software, and it is found that the addition of alternating current makes the stableness distribution of equilibrium points vary between time intervals. Secondly, with the help of bifurcation diagrams and corresponding time response diagrams, the effect of induced current on the boundary dynamic behavior is investigated in detail, meanwhile, the conditions for switching motions on separated boundaries are revealed. Finally, the multi-neuron coupling synchronization is explored by setting the corresponding coupling model. The results are beneficial to understand the boundary dynamic mechanism of neurons.
Signatures of quantized magnetic field on the nonlinear Landau damping of transverse electromagnetic waves
Authors: Rozina Ch , Asma A , Poedts S , Ali S , Shah H A
Published: July 2023

A quantum kinetic approach alongwith the Landau theory of quantization (LQ) is utilized to study the impact of the magnetic field on the nonlinear Landau damping (NLD) of transverse electromagnetic (EM) waves in a degenerate electron-ion plasma. The gyratory motion of fermions around the magnetic field (H) lines gets quantized into the Landau levels and consequently the associated Fermi–Dirac distribution function becomes modified with the fermion cyclotron frequency under the limit l
ℏ
ω

ce
− ε

Fe
≫ k

B

T

e
, where l is the orbital quantum number with all other standard notations. In this context, the density oscillations due to electrons are calculated in the presence of the LQ parameter η( = ℏ
ω

ce
/ε

Fe
< 1) and ion density perturbations are computed using the framework of Maxwell distribution. A new type of kinetic nonlinear Shrödinger equation is derived in the presence of η, which involves nonlocal nonlinear term responsible for the NLD of EM waves. Furthermore, longitudinal wave modes are investigated to account for quantization parameter η. The LQ is also shown to absorb oscillation spectra of the linear ion-acoustic mode. The present findings might be helpful to understand the impact of the H field on the nonlinear interaction of EM waves with astrophysical plasmas, e.g., in the atmosphere of neutron star the presence of quantized magnetic field is more common.
Optimal performance of the stochastic thermodynamic engine with a periodic heat bath
Authors: Fu Rui , Wang Qingyun
Published: July 2023

Stochastic thermodynamics provides a conceptual framework for describing the fluctuating behavior of small systems like colloids or biomolecules far from thermodynamic equilibriums but still contacted with a heat bath. In contrast to most literature focusing on the classical paradigm of Carnot engines, we herein study the optimal performance of the thermodynamic heat engine with a heat bath that periodically changes temperature, which is outside controllable by a time-dependent harmonic potential. Under reasonable assumptions on the control actuation, we derive the achievable upper bound for the maximal power and also the optimal control protocol. In addition, we also obtain the corresponding efficiency at maximal power, which only depends on the ratio of the minimal and maximal value of the temperature profile.
Magnetic field optimization of hall thruster with large height-radius ratio for high specific impulse operation
Authors: Fan Haotian , Wang Shangmin , Li Pei , Wei Liqiu , Li Hong , Guo Ning , Ding Yongjie
Published: July 2023

Hall thrusters with large height-radius ratio not only have incalculable application values in reducing the volume and weight of thrusters, but also have the potential advantages of higher discharge performance and longer service life. However, the lower propellant density in the main ionization zone and the higher electron temperature in the channel aggravate the loss of propellant and current under high voltage, and significantly reduce the discharge efficiency under high specific impulse mode. To improve the discharge performance of Hall thrusters with large height-radius ratio under high voltage, an optimization scheme of internally loaded magnetic field was proposed in this work. The simulation results show that under the internally loaded magnetic field, both the ionization zone and the acceleration zone move toward the inside of the channel. Although the ion loss on the walls increases, the higher propellant density at the channel upstream greatly promotes the increase of ionization rate and significantly improves the propellant utilization efficiency. The second zone crossed by magnetic field lines in the channel can be established by the internally loaded magnetic field, which enhances the magnetic field intensity on the inner and outer walls, and reduces the electron temperature near the channel outlet significantly. So that the axial conduction of electrons is effectively restrained and the current utilization efficiency is greatly improved. With the introduction of internally loaded magnetic field, the total efficiency of HEP-1350PM can be increased by 7.2% at 400 V. Moreover, the performance optimization effect brought by the internally loaded magnetic field will be gradually amplified with the increase of discharge voltage, which makes the Hall thruster with large height-radius ratio expected to achieve high-efficiency discharge under higher specific impulse.
The impact of anisotropic redshift distributions on angular clustering
Authors: Baleato Lizancos Antón , White Martin
Published: July 2023

A leading way to constrain physical theories from cosmological observations is to test their predictions for the angular clustering statistics of matter tracers, a technique that is set to become ever more central with the next generation of large imaging surveys. Interpretation of this clustering requires knowledge of the projection kernel, or the redshift distribution of the sources, and the typical assumption is an isotropic redshift distribution for the objects. However, variations in the kernel are expected across the survey footprint due to photometric variations and residual observational systematic effects. We develop the formalism for anisotropic projection and present several limiting cases that elucidate the key aspects. We quantify the impact of anisotropies in the redshift distribution on a general class of angular two-point statistics. In particular, we identify a mode-coupling effect that can add power to auto-correlations, including galaxy clustering and cosmic shear, and remove it from certain cross-correlations. If the projection anisotropy is primarily at large scales, the mode-coupling depends upon its variance as a function of redshift; furthermore, it is often of similar shape to the signal. In contrast, the cross-correlation of a field whose selection function is anisotropic with another one featuring no such variations — such as CMB lensing — is immune to these effects. We discuss explicitly several special cases of the general formalism including galaxy clustering, galaxy-galaxy lensing, cosmic shear and cross-correlations with CMB lensing, and publicly release a code to compute the biases.
Vector method of strain estimation in OCT-elastography with adaptive choice of scale for estimating interframe phase-variation gradients
Authors: Zykov Alexey A , Matveyev Alexander L , Sovetsky Alexander A , Matveev Lev A , Zaitsev Vladimir Y
Published: July 2023

In this paper we present a method which significantly improves strain-estimation quality in phase-sensitive optical coherence elastography (OCE). Specifically, we consider the realization of phase-sensitive OCE termed ‘vector method’, among main advantages of which are its high computational efficiency and high robustness with respect to measurement noises. The method does not require any search operations, but the quality of local strain estimation heavily depends on the quality of numerical spatial differentiation of inter-frame phase variations. This differentiation does not require phase unwrapping even for supra-wavelength displacements of scatterers, but the differentiation results depend on the chosen scale for phase-gradient estimation. Either too small or too large scale may strongly degrade the results of elastographic visualization, especially in the presence of pronounced spatio-temporal strain inhomogeneity. The proposed adaptive automatic choice of the differentiation scale complements earlier proposed vector averaging and significantly improves strain-mapping quality in OCE. The method efficiency is demonstrated using both numerically simulated and real OCT scans.