bluuebunny/crossref_metadata_2025 huggingface dataset:
COVID-19-Impfung: Motivations- und Belastungsfaktoren – Eine
Querschnittserhebung bei Ärzt*innen und Medizinischen
Fachangestellten in Deutschland
Authors: Schütte Ann-Kathrin , Wattenberg-Karapinar Ivonne , Hornberg Claudia , Lätzsch Rebecca
Published: October 2023

Ziel Ziel der Studie war die Bereitstellung von Ergebnissen zu
Motivations- und Belastungsfaktoren bezogen auf die COVID-19-Impfkampagne bei
ambulanten Ärzt*innen und Medizinischen Fachangestellten (MFA)
in Deutschland.

Methodik Im Rahmen einer quantitativen, nicht-repräsentativen
Online-Erhebung wurden insgesamt 514 Ärzt*innen und MFA aus
unterschiedlichen oder der selben Praxis zu Teilnahmegründen und
-hindernissen an der Impfkampagne, organisatorischen Rahmenbedingungen –
auch bezogen auf Impfstofflieferungen und -verfügbarkeit – sowie
die Arbeitsbelastung befragt.

Ergebnisse 70,3% der Befragten waren Ärzt*innen
und 28,8% waren MFA. In beiden Berufsgruppen kommt die Mehrzahl aus
Nordrhein-Westfalen (insgesamt 73,7%). Hauptmotivationsgründe
für die Teilnahme an der Impfkampagne waren der Beitrag zur
Bekämpfung der Pandemie (92,3%) und das Vorantreiben der
Impfkampagne (90,1%). Bei 94,6% der Befragten war die
Arbeitsbelastung seit Beginn der Impfkampagne im April 2021 gestiegen. Zentrale
Belastungsfaktoren waren der erhöhte bürokratische Aufwand
(92,5%), die Terminvergabe für die Impfungen (91%),
Patient*innenanfragen (90,3%) und der
Mehraufwand/Überstunden (83%). Als Grund für die
Nichtteilnahme an der Impfkampagne wurde ein zu hoher bürokratischer
Aufwand (69,6%) am häufigsten genannt.

Schlussfolgerung Eine Vielzahl der Praxen leistet mit der Teilnahme an der
COVID-19-Impfkampagne einen zentralen Beitrag zur Bekämpfung der
Pandemie, damit verbunden ist jedoch auch eine hohe Belastungssituation. Die
Dynamik des Infektionsgeschehens sowie häufig veränderte
Anforderungen und politische Vorgaben an die impfenden Praxen verstärken
dies noch. Der Wunsch nach einem einheitlichen und weniger
bürokratischen Vorgehen ist groß.
Combination Foley Catheter–Oxytocin versus Oxytocin Alone following Preterm Premature Rupture of Membranes
Authors: Gomez Slagle Helen B. , Hoffman Matthew K. , Sciscione Anthony C. , Ma'ayeh Marwan
Published: October 2023

Objective The benefit of mechanical ripening agents following preterm premature rupture of membranes (PPROM) has not been established. We sought to compare the time to delivery in women who received transcervical Foley catheter plus oxytocin infusion versus oxytocin infusion alone in patients with unfavorable cervices and PPROM.

Study Design This is a retrospective cohort study of patients presenting with PPROM of a live, singleton gestation between 240/7 and 366/7 weeks' gestation from January 2005 to October 2018 at a single, tertiary care institution. Patients with an unfavorable cervical examination (≤2-cm dilation), no contraindication to labor and undergoing labor induction were analyzed. Time to delivery was analyzed using multivariable linear regression adjusting for cervical dilation at induction and nulliparity. Bivariate and multivariate analyses were used where appropriate.

Results A total of 260 participants were included: 109 who received a Foley catheter and oxytocin (Foley/oxytocin) and 151 who had oxytocin alone. Demographic characteristics were similar between the two groups. Unadjusted time to delivery was significantly shorter in the oxytocin only group (Foley/oxytocin: 20.35 hours vs. oxytocin alone: 14.7 hours, p < 0.001). No differences in length of labor were detected after adjusting for cervical dilation at induction and nulliparity (p = 0.5). The unadjusted rate of cesarean delivery was higher in the combination Foley/oxytocin group (Foley/oxytocin: 16.5% vs. oxytocin alone: 7.3%, p = 0.03), but no differences were found in the adjusted analysis (p = 0.06). There were no differences in clinical chorioamnionitis rates between the two groups (Foley/oxytocin: 8.3% vs. oxytocin alone: 9.3%, p = 0.83). Furthermore, no significant differences were found in maternal and neonatal outcomes between the two groups.

Conclusion In patients with PROM, the use of a transcervical Foley catheter in addition to oxytocin is not associated with a shorter time to delivery compared with oxytocin alone.

Key Points
Delivery Outcomes and Postpartum Readmissions Associated with Ehlers–Danlos Syndrome
Authors: Wright Gillian L. , Wen Timothy , Engel David J. , Guglielminotti Jean , Andrikopoulou Maria , Booker Whitney A. , D'Alton Mary E. , Friedman Alexander M.
Published: October 2023

Objective Given that updated estimates of Ehlers–Danlos syndrome and risks for obstetric complications including postpartum readmission may be of public health significance, we sought to analyze associated obstetric trends and outcomes in a nationally representative population.

Study Design The 2016 to 2020 Nationwide Readmissions Database was used for this retrospective cohort study. Delivery hospitalizations to women aged 15 to 54 with and without Ehlers–Danlos syndrome were identified. Temporal trends in Ehlers–Danlos syndrome diagnoses during delivery hospitalizations were analyzed using joinpoint regression to estimate the average annual percent change with 95% confidence intervals (CIs). To determine whether adverse obstetric outcomes during the delivery were associated with Ehlers–Danlos syndrome, unadjusted and adjusted logistic regression models were fit with unadjusted (odds ratio [OR]) and adjusted ORs with 95% CIs as measures of association. In addition to analyzing adverse delivery outcomes, risk for 60-day postpartum readmission was analyzed.

Results An estimated 18,214,542 delivery hospitalizations were included of which 7,378 (4.1 per 10,000) had an associated diagnosis of Ehlers–Danlos syndrome. Ehlers–Danlos syndrome diagnosis increased from 2.7 to 5.2 per 10,000 delivery hospitalization from 2016 to 2020 (average annual percent change increase of 16.1%, 95% CI: 9.4%, 23.1%). Ehlers–Danlos syndrome was associated with increased odds of nontransfusion severe maternal morbidity (OR: 1.84, 95% CI: 1.38, 2.45), cervical insufficiency (OR: 2.14, 95% CI: 1.46, 3.13), postpartum hemorrhage (OR: 1.41, 95% CI: 1.17, 1.68), cesarean delivery (OR: 1.26, 95% CI: 1.17, 1.36), and preterm delivery (OR: 1.35, 95% CI: 1.16, 1.56). Estimates for transfusion, placental abruption, and placenta previa did not differ significantly. Risk for 60-day postpartum readmission was 3.0% among deliveries with Ehlers–Danlos (OR: 1.76, 95% CI: 1.37, 2.25).

Conclusion Ehlers–Danlos syndrome diagnoses approximately doubled over the 5-year study period and was associated with a range of adverse obstetric outcomes and complications during delivery hospitalizations as well as risk for postpartum readmission.

Key Points
Pilot study of an endoluminal-suturing device as a treatment for patients with gastroesophageal reflux disease
Authors: Louis Hubert , Van Ouytsel Pauline , Leclercq Loulia , Houinsou Hans Mélina , Devière Jacques , Rio-Tinto Ricardo , Huberty Vincent
Published: October 2023

Background and study aims Endoscopic therapy is a promising
option for patients with gastroesophageal reflux disease (GERD). The aim of this study was to
assess safety and feasibility of the Endomina suturing platform as a treatment for
GERD.

Patients and methods This was a two-center study of patients with
chronic GERD symptoms that responded at least partially to proton pump inhibitors (PPIs).
Primary endpoints were to assess the safety of the procedure and persistence of the sutures.
Secondary endpoints were to assess esophageal pH-impedance and manometry parameters changes at
6 months, as well as GERD symptoms and PPI use up to 12 months of follow-up.

Results Fourteen patients were treated (13 males, mean of 43±12
years), with a mean number of three plications per patient. Thirteen, 10, and nine patients
were analyzed at 3, 6, and 12 months of follow-up, respectively. One device-related adverse
event occurred (loss of needle tip requiring endoscopic retrieval 1 week later). A mean of two
plications persisted at 3 and 12 months. A decrease in median acid exposure time and reflux
episodes was observed after the procedure. Mean Reflux Symptom Index and GERD-Health-Related
Quality of Life scores decreased during follow-up visits and 90% of the patients discontinued
PPI use at 1 year.

Conclusions Endoscopic full-thickness suturing of the
esophagogastric junction with the Endomina suturing platform is feasible, allowing persistence
of two-thirds of the plications, with promising results for decreasing reflux and improving
GERD symptoms.
Point of Care Ultrasound in Pediatric Surgery across the European Region—European Pediatric Surgery Association Endorsed Survey
Authors: Lindert Judith , Rolle Udo , Naidoo Gerlin
Published: October 2023

Introduction Our purpose was to assess the state of training, clinical practice, and barriers to use point-of-care ultrasound (POCUS) in pediatric surgery in Europe.

Methods An electronic survey was disseminated among European pediatric surgeons utilizing the European Pediatric Surgery Association network and other existing networks.

Results There were 186 respondents from 27 European countries and 7 non-European countries. In most countries (86.6%; N = 161), the initial ultrasound for acute admissions is performed by radiologists, with 1 to 6 hours turnover in 62.9% (N = 117) of urgent cases. Ultrasound by pediatric surgeons (point-of-care ultrasound/POCUS) is performed by 48.4% (N = 90) of respondents, with 29% (N = 54) using it at least once per week. The most common indications for POCUS include abdominal focused abdominal sonography in trauma (53.8%; N = 100), diagnosis of appendicitis (41.9%; N = 78), and intussusception (44.6%; N = 84). In malrotation-volvulus, 28.5% (N = 53) used ultrasound for its diagnosis, while 27.5% (N = 51) would not see an indication here. Training in POCUS occurred informally for 55.4% (N = 103) of participants, while 31.2% (N = 58) attended formal training courses. Almost all respondents wanted to attain further POCUS training (89.3%; N = 166), only 7% (N = 13) did not think this would be useful. For 73.1% (N = 136), POCUS is not currently part of the pediatric surgery training curriculum in their country. Perceived barriers to POCUS use include a lack of training opportunities (26.3% [N = 49]) and a paucity of portable ultrasound machines (17.8% [N = 33]).

Conclusion There is a wide spectrum of POCUS use in pediatric surgery across Europe. For those surgeons who practice POCUS, it is most used for the diagnosis of abdominal conditions. There are differing views among clinicians concerning the most useful applications of POCUS. The extent to which ultrasound is taught during pediatric surgery training differs substantially across European curricula.
Practical Site-selective Oxidation of Glycosides with Pd(OAc)2/Neocuproine
Authors: Reintjens Niels , Bartels Imke , Marinus Nittert , Massmann Sarina , Bunt Daan , Walvoort Marthe , Witte Martin , Minnaard Adriaan
Published: October 2023

Palladium-catalyzed oxidation of the secondary C3 hydroxy group in glycopyranosides has set its mark in the selective modification of unprotected carbohydrates. The pre-formed catalyst [(neocuproine)PdOAc]2(OTf)2 oxidizes besides monosaccharides also di-, and oligosaccharides. Here, we provide a more convenient protocol for this reaction in which the Pd-catalyst is formed in situ from Pd(OAc)2 and neocuproine in methanol at 50 °C. Together with a simplified product isolation, this protocol is applied to a series of mono- and disaccharides and has been applied on 10-gram scale. The protocol is also valuable as a screening method to determine whether more extensive studies using the pre-formed catalyst are worthwhile.
Immunometabolic and Vascular Health Responses among High Endurance
Trained Subjects
Authors: Fonseca Henrique A.R. , Bittencourt Celia Regina , Monteiro Andrea Moreira , Fonseca Francisco Antonio , Sanches Lívia Rentas , Ferreira Carlos Eduardo dos Santos , Neto Antonio Martins Figueiredo , Gidlund Magnus , Izar Maria Cristina
Published: October 2023

In this study, we aimed to examine the impact of high endurance training on
vascular health parameters and immune-endocrine responses against modified
low-density lipoprotein (LDL) particles. This observational, cross-sectional
study included high endurance-trained and healthy non-trained subjects. Vascular
ultrasound was used to assess vascular health parameters based on carotid
intima-media thickness and endothelial function (flow-mediated dilation).
Enzyme-linked immunosorbent assays were used to measure interleukin (IL)-8 and
IL-10, autoantibody isotypes anti-oxidized LDL (oxLDL) and anti-apolipoprotein B
(ApoB-D) peptide. Plasma levels of the corticosterone and 17
α-hydroxyprogesterone hormones were analyzed by mass spectrometry. This
study enrolled 96 subjects, of whom 44 were high endurance trained and 52 were
healthy non-trained individuals. Smaller carotid intima-media thickness values
were observed in the high-endurance trained than in the healthy non-trained
males, while no differences were observed between female groups. Flow-mediated
dilation measurements did not differ by training or sex. The humoral immune
responses to IgG anti-oxLDL and IgM anti-ApoB-D autoantibodies showed an isotype
imbalance between the high-endurance trained and the non-trained groups.
Immunoendocrine parameters showed inverse correlations between 17
α-hydroxyprogesterone concentrations and carotid intima-media thickness
measurements. Direct correlations were found between IL-10 concentrations and
flow-mediated dilation measurements. Chronic high-endurance exercise modulates
immune-endocrine and vascular health parameters, in a sex-dependent manner.
An explorative qualitative study of cyberbullying and cyberstalking in a higher education community
Authors: Bussu Anna , Ashton Sally-Ann , Pulina Manuela , Mangiarulo Marta
Published: October 2023

The literature suggests an increased risk of cybervictimisation during the COVID-19 pandemic. This paper explores student and staff experiences in a higher education community as victims of cyberbullying and cyberstalking during the COVID-19 lockdowns. An online semi-structured questionnaire was administered to self-identified students and staff victims within a higher education context. By analysing victim responses, within a qualitative framework, this research identifies perceptions, impacts and support mechanisms. The findings offer insights for the development of effective practices and policies to mitigate risk factors and foster resilience. This research addresses the need for comprehensive understanding in the face of emerging digital challenges and future traumatic events.
Market orientation practices of Ethiopian seed producer cooperatives
Authors: Sisay Dawit Tsegaye , Verhees Frans J. H. M. , van Trijp Hans C. M.
Published: October 2023

The practices of market orientation are context-specific. This paper focuses on the concept and practices of market orientation in Ethiopian seed producer cooperatives (SPCs). Based on 44 semi-structured interviews with experts and practitioners (SPC leaders and member farmers), we identify key market orientation elements in the SPCs’ context. Market orientation criteria in the Ethiopian SPC context could meaningfully be grouped into five underlying dimensions: quality of produce, business organization, external orientation, value addition activities, and supplier access. The understanding of market orientation by practitioners, particularly by member farmers, is limited to quality seed production. There is considerable recognition among respondents of the importance of customer orientation in the SPC context. Information on produced seeds, market prices, and profits is considered important. Information on competitors, although recognized by experts as important, is not really gathered by SPCs. Experts believe that the SPC committees should be responsible for information dissemination, but in practice, there is also an important role for the SPC chairman personally. Market-oriented practices in SPCs contribute to increasing employment and productivity and ensuring food security. Policymakers should devise strategies to support SPCs in becoming more market-oriented and successful in their business ventures. Specific market orientation practices by SPCs are discussed in detail.
Digitalized grammatization and critical thinking: synthesizing Chinese Chan pedagogy and Bernard Stiegler’s negentropic knowledge
Authors: Wu Amiao
Published: October 2023

This paper attempts to initiate a dialogue between Bernard Stiegler’s theories and Chinese Chan philosophy for a new vision of critical thinking. Specifically, I argue that Chan way of teaching can be aligned with Stiegler’s emphasis on recovering negentropic potentials and maintaining a noetic awareness within the context of algorithmic life. First, I present Stiegler’s discussion of intergenerational relations in transmitting true knowledge and his concerns about the liquidation of cognitive capabilities among younger generations. Second, I show how Chan teaching via the koan system may open up a perspective for transmitting “noetic experiences” and accentuating young people’s critical faculties. Then, I examine “the ordinary mind” of Chan teaching and consider how it corresponds to Stiegler’s negentropic form of knowledge. Finally, I contend that fostering critical thinking is to encourage young people to engage in lived activities and liberate them from the entropic non-becoming of digitalized grammatization.
The influence of communication climate, organizational identification, and burnout on real estate agents’ turnover intention
Authors: Lee Chun-Chang , Zheng Yu-Ru , Yeh Wen-Chih , Yu Zheng
Published: October 2023

This study investigated the factors that affect the turnover intention of real estate agents by considering the impact of individual-level factors such as job stress, burnout, and salary level and team-level factors such as communication climate and organizational recognition. The parameters were evaluated using a hierarchical linear moderated mediation model. The survey subjects were real estate agents in Tainan City. A total of 870 questionnaires were distributed to 87 real estate agencies, and 615 questionnaires from 77 branches were collected. The questionnaires from four branches were excluded, as fewer than two questionnaires were collected, and an additional 57 questionnaires with missing responses were also excluded. A total of 558 questionnaires from 73 branches were included in the study. The overall response rate of questionnaires was 64.1%. The results indicated that the greater a real estate agent’s awareness of the communication climate, the higher the likelihood of the real estate agent receiving recognition from their organization, while a higher salary level indicated a lower level of turnover intention. A greater understanding of job stress indicated a higher risk of burnout. The communication climate had an impact on burnout and turnover intention, while organizational recognition mediated the impact of communication climate as it pertained to turnover intention. The results showed that the level of burnout mediated the impact of job stress and turnover intention.
Lead halide perovskites for radiation detectors: Perspectives
Authors: Wessels Bruce W.
Published: October 2023

Halide perovskite, Bridgman grown single crystals have shown excellent performance for high energy radiation detectors. CsPbBr3 perovskite detectors with 1.4% energy resolution have been demonstrated. These detectors demonstrate a wide range of operations from −2 to 70 °C. Semiconductor hard radiation detectors have been used for applications in defense, medicine, and bioelectronics. In most of these applications, there is a need for the detectors to operate at room temperature and above. Previous hard radiation detector devices have used the material cadmium zinc telluride for room temperature operation [Luke et al., IEEE Trans. Nucl. Sci. 48, 282 (2001)]. There are now other semiconductors that show considerable promise. These include the halide perovskite compound semiconductors with a formula CsPbX3, where X = Cl, Br, I [Liu et al., Proc. SPIE 8852, 88520A (2013); Peters et al., J. Lumin. 243, 118661 (2022)]. These materials are also being developed for other device applications, including light-emitting diodes, lasers, solar cells, and photodetectors. It is claimed that these semiconductors are defect-tolerant, although the reason for this behavior is not well understood. Thermally stimulated current spectroscopy was used to detect electron traps in these materials to improve their performance. The halide compound cesium lead bromide has a bandgap of 2.25 eV, which makes it suitable for room temperature operation and above. They also have high permittivity. These halide perovskite semiconductors have shown room temperature detector device performance. Recently, we demonstrated hard radiation detectors using CsPbBr3 as the device platform. The detectors had 1.4% energy resolution for high-energy γ rays [He et al., Nat. Photonics 15, 36 (2021)]. The detectors demonstrate a wide temperature region from −2 to 70 °C for stable operations.
Magnetic fluid flow rate and thermal characteristics of hydraulic turbine spindle magnetic fluid seals
Authors: Li Zhenggui , Wang Ziyue , Cheng Jie , Zhu Guoqing , Yan Shengnan , Chen Fang
Published: October 2023

The flow and temperature properties of the magnetic fluid are the primary elements impacting the seal stability in the main shaft magnetic fluid seal of the turbine. This study investigated the eddy current and heat field of the magnetic fluid at the seal gap using a mix of numerical computation and experiment and came to the following conclusions: Under the pole tooth groove and the permanent magnet, the magnetic fluid creates symmetrical vortices in the clearance of the magnetic fluid seal device. Below the pole tooth, the magnetic fluid velocity is minimal and essentially constant. The pole shoe and spindle next to the air side of the magnetic fluid seal device have the lowest temperature, and the device’s core has the greatest temperature.
Cryogenic cold energy recovery in liquid hydrogen refueling station with double-pipe heat exchanger
Authors: Hu Rongze , Yang Bin , Shi Cunyang , Xue Mingzhe , Zhu Shaowei
Published: October 2023

Recovering the cryogenic cold energy of liquid hydrogen (LH2) for precooling high-pressure hydrogen gas before refueling can significantly reduce the electricity and energy consumption of liquid hydrogen refueling stations. Existing methods, such as blending, require continuous cryogenic pump operation and are not suitable for various operating conditions. This work proposes a novel method to recover LH2 cryogenic cold energy using a double-pipe heat exchanger, which can decouple the compression and refueling process and meet the fluctuating demand for the cryogenic cold energy required by the hydrogen dispenser. The lumped parameter method and temperature partition method were adopted to design the heat exchanger structure. Numerical simulations of a 2D axisymmetric swirl model were done to verify the accuracy of the temperature partition method applied to high-pressure cryogenic hydrogen. Due to the low temperature of LH2, the secondary refrigerant dichloromethane (CH2Cl2) risks freezing. Comparing the outer wall surface temperature of the inner pipe with the CH2Cl2 freezing point temperature, the optimal anti-freezing condition is that the outer pipe nominal diameter should be selected as 0.032 m and CH2Cl2 mass flow rate should be at least 1.72 kg s−1. Recovery efficiency can reach over 75.39% without freezing.
Existence of infinitely many weak solutions to Kirchhoff–Schrödinger–Poisson systems and related models
Authors: Kim Jae-Myoung , Yang Soo-Oh , Bae Jung-Hyun
Published: October 2023

In this article we investigate the existence of infinitely many weak solutions for Kirchhoff–Schrödinger–Poisson systems via the critical point theory. We obtain infinitely many large energy solutions and negative energy solutions of the system with superlinear nonlinearities by using the fountain theorem and the dual fountain theorem, respectively. Moreover, we establish the existence of infinitely many weak solutions of the problem with sublinear nonlinearities by applying the genus theory introduced by Krasnolsel’skii [Topological Methods in the Theory of Nonlinear Integral Equations (The Macmillan Company, New York, 1964)]. In particular, we do not use the classical Ambrosetti–Rabinowitz condition.
On the circularly polarized luminescence of individual triplet sublevels
Authors: Climent Clàudia , Schelter Eric J. , Waldeck David H. , Vinogradov Sergei A. , Subotnik Joseph E.
Published: October 2023

We discuss the possibility of using circularly polarized luminescence (CPL) as a tool to probe individual triplet spin sublevels that are populated nonadiabatically following photoexcitation. This study is motivated by a mechanism proposed for chirality-induced spin selectivity in which coupled electronic-nuclear dynamics may lead to a non-statistical population of the three triplet sublevels in chiral systems. We find that low-temperature CPL should aid in quantifying the exact spin state/s populated through coupled electronic-nuclear motion in chiral molecules.
Stable high repetition-rate laser-driven proton beam production for multidisciplinary applications on the advanced laser light source ion beamline
Authors: Catrix Elias , Boivin Frédéric , Langlois Kassandra , Vallières Simon , Boynukara Canan Yağmur , Fourmaux Sylvain , Antici Patrizio
Published: October 2023

Laser-driven proton accelerators are relevant candidates for many applications such as material science or medicine. Today, there are multi-hundred-TW table-top laser systems that can generate relativistic peak intensities >1018 W/cm2 and routinely reach proton energies in the MeV range. However, for most desired applications, there is still a need to optimize the quality and stability of the laser-generated proton beam. In this work, we developed a 0.625 Hz high repetition-rate setup in which a laser with 2.5% RMS energy stability is irradiating a solid target with an intensity of 1019 to 1020 W/cm2 to explore proton energy and yield variations, both with high shot statistics (up to about 400 laser shots) and using different interaction targets. Investigating the above-mentioned parameters is important for applications that rely on specific parts of the proton spectrum or a high ion flux produced over quick multi-shot irradiation. We demonstrate that the use of a stable “multi-shot mode” allows improving applications, e.g., in the detection of trace elements using laser-driven particle-induced x-ray emission.
Reversal of the skyrmion topological deflection across ferrimagnetic angular momentum compensation
Authors: Berges L. , Weil R. , Mougin A. , Sampaio J.
Published: October 2023

Due to their non-trivial topology, skyrmions describe deflected trajectories, which hinders their straight propagation in nanotracks and can lead to their annihilation at the track edges. This deflection is caused by a gyrotropic force proportional to the topological charge and the angular momentum density of the host film. In this article, we present clear evidence of the reversal of the topological deflection angle of skyrmions with the sign of angular momentum density. We measured the skyrmion trajectories across the angular momentum compensation temperature (TAC) in GdCo thin films, a rare earth/transition metal ferrimagnetic alloy. The sample composition was used to engineer the skyrmion stability below and above the TAC. A refined comparison of their dynamical properties evidenced a reversal of the skyrmions deflection angle with the total angular momentum density. This reversal is a clear demonstration of the possibility of tuning the skyrmion deflection angle in ferrimagnetic materials and paves the way for deflection-free skyrmion devices.
Thermoelectric transport properties of Si, SiGe, and silicide CMOS-compatible thin films
Authors: Schwinge Caroline , Hoffmann Raik , Hertel Johannes , Wislicenus Marcus , Gerlich Lukas , Völklein Friedemann , Gerlach Gerald , Wagner-Reetz Maik
Published: October 2023

Characterization of thermoelectric transport properties for temperature sensing, cooling, and energy harvesting applications is necessary for a reliable device performance in progressively minimized computer chips. In this contribution, we present a fully automated thermovoltage and sheet resistance measurement setup, which is calibrated and tested for the production of silicon- and silicon-germanium-doped as well as silicide complementary metal–oxide–semiconductor-compatible thin films. A LabVIEW-programmed software application automatically controls the measurement and recording of thermovoltages at individually defined temperature set points. The setup maps average temperature and temperature differences simultaneously in the regime from 40 to 70 °C. The Seebeck coefficient calculated by means of the inversion method was used to eliminate the offset voltage influence. Finally, we present and discuss the Seebeck coefficient as well as the sheet resistance for application-specific different temperature set points of several doped poly-Si, poly-SiGe, and silicides.
Compact chirped fiber Bragg gratings for single-photon generation from quantum dots
Authors: Remesh Vikas , Krämer Ria G. , Schwarz René , Kappe Florian , Karli Yusuf , Siems Malte Per , Bracht Thomas K. , Covre da Silva Saimon Filipe , Rastelli Armando , Reiter Doris E. , Richter Daniel , Nolte Stefan , Weihs Gregor
Published: October 2023

A scalable source of single photons is a key constituent of an efficient quantum photonic architecture. To realize this, it is beneficial to have an ensemble of quantum emitters that can be collectively excited with high efficiency. Semiconductor quantum dots hold great potential in this context due to their excellent photophysical properties. Spectral variability of quantum dots is commonly regarded as a drawback introduced by the fabrication method. However, this is beneficial to realize a frequency-multiplexed single-photon platform. Chirped pulse excitation, relying on the so-called adiabatic rapid passage, is the most efficient scheme to excite a quantum dot ensemble due to its immunity to individual quantum dot parameters. Yet, the existing methods of generating chirped laser pulses to excite a quantum emitter are bulky, lossy, and mechanically unstable, which severely hampers the prospects of a quantum dot photon source. Here, we present a compact, robust, and high-efficiency alternative for chirped pulse excitation of solid-state quantum emitters. Our simple plug-and-play module consists of chirped fiber Bragg gratings, fabricated via femtosecond inscription, to provide high values of dispersion in the near-infrared spectral range, where the quantum dots emit. We characterize and benchmark the performance of our method via chirped excitation of a GaAs quantum dot, establishing high-fidelity single-photon generation. Our highly versatile chirping module coupled to a photon source is a significant milestone toward realizing practical quantum photonic devices.
Physical properties with high specific loss power of magnetite (Fe3O4) synthesized via thermal decomposition technique
Authors: Uddin Md Kamal , Deb Nandita , Rashid Rimi , Das Harinarayan , Syed Ishtiaque M. , Hoque Sheikh Manjura
Published: October 2023

Magnetic iron oxide nanoparticles have versatile applications in biomedical science that require control over shape and size distribution. Thermal decomposition is one of the best methods for controlling the size and shape of produced nanoparticles (NPs). The size distribution can be tuned (5–30 nm) by varying the reaction environment such as precursor concentration, amount of solvent used, temperature ramp, and reflux time. Iron oleate was used as a precursor solution and heated up to reflux temperature (310 °C) for 10 min within the oxygen-free environment by applying N2 gas flow. The XRD pattern confirmed the formation of NPs with a crystallite size of 17 ± 2.45 nm. Transmission electron microscope images showed moderately cubic shapes with a mean particle size of 28.67 ± 7.12 nm. Magnetic properties such as saturation magnetization, coercivity, and remanence were calculated at 23.48 emu/gm, 33 Oe, and 0.6 emu/gm, respectively, which indicated the ferromagnetic nature of the NPs. The Verwey transition was identified from the magnetization vs temperature (FC-ZFC) plot. The bondings of the oleic acid surfactant with the produced NPs were confirmed from Fourier transformation infrared spectroscopy (FTIR) data analysis. For the application of hyperthermia, the hydrophobic phase was transferred to the hydrophilic phase using cetyltrimethylammonium bromide, which was assured by the FTIR data analysis. The hyperthermia heating of NPs was measured for different concentrations of NPs (0.25, 0.5, 1, 2, and 4 mg/ml), from which specific loss power (SLP) was calculated. Among them, 0.25 mg/ml produced the most prominent SLP (2149 ± 309 w/g) that can be applied for targeted cancer treatment.
Memtransistor-like operation of devices made by graphene/h-BN/MoS2 van der Waals heterostructure
Authors: Chien Shih-Po , Liang Bor-Wei , Chang Wen-Hao , Wang Bo-Wen , Feng Yi-Jie , Chen Yi-Cheng , Lan Yann-Wen
Published: October 2023

We present the fabrication and characterization of a flash memory device based on a van der Waals (vdW) heterostructure comprising graphene (Gr), hexagonal boron nitride (h-BN), and molybdenum disulfide (MoS2). The device exhibits versatile functionalities and demonstrates memtransistor-like behavior, making it a promising candidate for synaptic devices and neuromorphic computing. The Gr/h-BN/MoS2 heterostructure allows for the manipulation of charge concentration in the floating gate (FG) through control gate voltage (VBG), resulting in conductance switching. Moreover, the overlap structure of the FG and source-drain electrodes enables memtransistor-like operations, where the writing processes rely on the source-drain voltage (VDS). By varying carrier storage concentrations in the Gr-FG, multiple memory states can be achieved, offering analog information processing capabilities. In addition, the combination of dual-input functionality allows for the identification of a substantial on/off ratio even when utilizing a lower reading VDS, consequently strengthening the dependability of the memory state. Our work showcases the great potential of the Gr/h-BN/MoS2 heterostructure for advanced nanoelectronics, providing a platform for the development of computing architectures and neuromorphic systems.
Effect of control domains of fractures and caves on reactive transport in porous media
Authors: Su Xuhang , Qi Ning , Li Xuesong , Chen Shengnan , He Long
Published: October 2023

It is often highly difficult to predict the main flow path of reactive fluids in porous media with complexly distributed fractures and/or caves. Based on Darcy's law, this research defines the control domain of fractures/caves that represents the interference range of fractures/caves. This control domain can be used to identify the connectivity possibility between fractures/caves and predict the flow paths of reactive fluids at the optimal flow rate. Furthermore, after simplifying the geometry of fractures/caves, a threshold geometric aspect ratio of 20 is set to distinguish fractures and caves, concerning the flow mechanisms, by clarifying the ranges of control domains. Moreover, the control domain theory is combined with the two-scale continuum model for acidizing carbonate rocks to estimate the flow paths of acid in fractured-vuggy carbonate rocks at an optimal flow rate, thereby validating the accuracy of the reactive fluid main flow path estimation based on the control domain theory. The primary criterion to determine the reactive transport in porous media with complex fracture/cave distribution is the overlap degrees of control domains of adjacent isobaric bodies along their width and length directions, while the directions of isobaric bodies offer supplementary material. If the control domains of two isobaric bodies overlap with each other perpendicular to the flow direction, these isobaric bodies have higher odds of connected fluid flow.
Fluid-based microbial processes modeling in Trichodesmium colony formation
Authors: Wei Heng , Hutchins David A. , Ronney Paul D. , Pahlevan Niema M.
Published: October 2023

In tropical and subtropical ocean gyres, Trichodesmium colonies account for up to half of the total N2 fixation in the ocean, making it one of the most ecologically significant N2-fixing cyanobacteria. The processes whereby Trichodesmium colonies and large-scale surface blooms form have not been investigated thoroughly. In particular, the effects of fluid motion have not been included in previous studies. As the first step toward understanding the mechanical processes associated with Trichodesmium colony synthesis, we propose a shear-related flow-based growth model to enlighten how fluid dynamics affect bacteria colony formation and growth. To investigate the possibility that early growth characteristics are strongly dependent on the shear rate, a two-way coupled fluid-colony interaction is developed using the lattice Boltzmann method for a porous colony. This model captures the exponential growth trend during the colony formation phase found in experiments. Our results show that the flow field significantly impacts both the colony growth rate and shape. In pure shear conditions, colonies grow in circular shapes, whereas in uniform flow, they take filament-like forms. Additionally, the Reynolds number (Re) plays a crucial role in shaping the colonies, especially in uniform flow conditions where its effect is more profound.
Electrostatic aid-free photo-floating gate two dimensional MoS2 synaptic transistors
Authors: Wang Rui , Jiang Yurong , Mou Dan , Zhang Suicai , Li Xueping , Yan Yong , Song Xiaohui , Xia Congxin
Published: October 2023

Synaptic transistors are important component of neuromorphic computing systems, which is promising to reduce data traffic, time delay, and energy cost. However, most of synaptic behaviors normally need the aid of electrostatic gate voltage, which induces considerable consumption. Here, we propose a structure of the electrostatic aid-free photo-floating gate transistor based on the MoS2/MoOx/WSe2 heterojunctions, in which the MoOx acts as a unipolarity barrier layer and WSe2 functions as a photo-floating gate layer. Compared with the traditional floating-gate transistors, the designed device exhibits the distinct characteristics of visual synapse behaviors without the electrostatic aid gate, including the multilevel storage property of 13 stages, paired-pulse facilitation, the transition of short time plasticity to long time plasticity, and learning-forgetting-learning. This work provides a feasible strategy to construct neuromorphic computing device with ultra-low energy consumption.
Heat flux from the surface in the process of the rupture of a thin liquid film by an electric field
Authors: Kupershtokh A. L. , Medvedev D. A. , Alyanov A. V.
Published: October 2023

In this article, the cooling of a solid surface by an evaporating film of a dielectric liquid and the influence of an electric field on this process are studied. The mesoscopic lattice Boltzmann method is applied to simulate the fluid flow with phase transitions and the heat transfer. The cases without electric field, with initially uniform electric displacement field, and with non-uniform electric field are considered. A uniform field enhances the cooling slightly. Non-uniform field leads to the rupture of the film. In this case, the local heat flux in local regions increases significantly when the film becomes thin and effectively evaporates. After the rupture of the film, the heat flux from a dry spot decreases abruptly. The formation of a dry spot can be prevented by switching off the electric field before the film rupture. Thus, we demonstrate the possibility of enhanced cooling of local regions at a surface using pulses of non-uniform electric field acting on a thin film of dielectric liquid placed at the surface. If the inflow of liquid to the film could be provided, it is in principle possible to realize a periodic process of application of voltage pulses to electrodes and to enhance the cooling of surface by the evaporation of a film of dielectric liquid.
X-ray induced photoconductivity and its correlation with structural and chemical defects in heteroepitaxial diamond
Authors: Grünwald T. , Bestele C. , Bosak M. , Zhao J. , Newton M. E. , Schreck M.
Published: October 2023

Three sets of heteroepitaxial diamond crystals grown under nominally identical process conditions on Ir/YSZ/Si(001) substrates have been studied with respect to structural defects, chemical purity, and x-ray induced photoconductivity (PC). The dislocation density that varied systematically between 107 and 109 cm−2 had a minor influence on dark conductivity and photoconductive gain G. In contrast, the substitutional nitrogen (NN) and substitutional boron (NB) defects, which are both present at very low concentrations (≤1 ppb), turned out to be the crucial factors controlling the electrical behavior. Small differences between both resulted in variations of the photocurrents by up to 5 orders of magnitude. The maximum in G of 0.75×104 was measured in the sample with highest dark conductivity. It could be explained conclusively within our model calculations on gain formation by NN≤NB. For low gain samples, we found NN>NB. However, the measured G values were far from theoretical predictions. This indicates a dominating role of additional traps. After x-ray switch-off, persistent photoconductivity (PPC) was observed in high gain samples. It was attributed to an energetic barrier hampering the recharging of nitrogen atoms by hole capture. As a possible source, strain fields generated by dislocations are suggested.
Multi-physical predictions in electro-osmotic micromixer by auto-encoder physics-informed neural networks
Authors: Chang Naiwen , Huai Ying , Liu Tingting , Chen Xi , Jin Yuqi
Published: October 2023

Electro-osmotic micromixers (EMMs) are used for manipulating microfluidics because of the advantages on electro-osmosis mechanisms. The intricate interdependence between various fields in the EMM model presents a challenge for traditional numerical methods. In this paper, the flow parameters and electric potential are predicted based on the solute concentration by utilizing the physics-informed neural networks (PINNs) method. The unknown spatiotemporal dependent fields are derived from a deep neural network trained by minimizing the loss function integrating data of scalar field and corresponding governing equations. Moreover, the auto-encoder structure is developed to improve the performance of PINNs in the EMM. The comparisons between the results of auto-encoder PINNs and previous PINNs show a reduction in relative errors for transverse and longitudinal velocities from 83.35% and 84.24% to 9.88% and 12.29%, respectively, in regions with large-gradient velocities. Furthermore, our results demonstrate that the proposed method is robust to noise in the scalar concentration.
Characterizing the origin band spectrum of isoquinoline with resonance enhanced multiphoton ionization and electronic structure calculations
Authors: Krogmeier Timothy J. , Pappas Emerson S. , Reardon Kylie A. , Rivera Marcos R. , Head-Marsden Kade , Parsons Bradley F. , Schlimgen Anthony W.
Published: October 2023

We report the experimental resonance enhanced multiphoton ionization spectrum of isoquinoline between 315 and 310 nm, along with correlated electronic structure calculations on the ground and excited states of this species. This spectral region spans the origin transitions to a π–π* excited state, which previous work has suggested to be vibronically coupled with a lower lying singlet n–π* state. Our computational results corroborate previous density functional theory calculations that predict the vertical excitation energy for the n–π* state to be higher than the π–π* state; however, we find an increase in the C–N–C angle brings the n–π* state below the energy of the π–π* state. The calculations find two out-of-plane vibrational modes of the n–π* state, which may be brought into near resonance with the π–π* state as the C–N–C bond angle increases. Therefore, the C–N–C bond angle may be important in activating vibronic coupling between the states. We fit the experimental rotational contour with a genetic algorithm to determine the excited state rotational constants and orientation of the transition dipole moment. The fits show a mostly in-plane polarized transition, and the projection of the transition dipole moment in the a-b plane is about 84° away from the a axis. These results are consistent with the prediction of our electronic structure calculations for the transition dipole moment of the π–π* excited state.
A comprehensive assessment on detached eddy simulation and delayed detached eddy simulation approaches in large-scale rotating separated flow in a centrifugal impeller under small flow rate
Authors: Pan Chaogang , Zhang Wei
Published: October 2023

This work performed a comprehensive comparative assessment on the capabilities and performances of detached-eddy simulation (DES) and delayed detached-eddy simulation (DDES) approaches in revealing the flow physics in a six-blade centrifugal impeller under a small flow rate. The numerical results are well validated by the experimental data of a similar configuration and are compared with the benchmark data generated by an additional large-eddy simulation investigation. The results are presented and analyzed in terms of the time-averaged flow field, the transient flow, and momentum transport characteristics. The capabilities of DES and DDES approaches in predicting the rotating turbulent flow are compared and assessed. The numerical results show that DES performs better in the pressure distribution, while DDES is superior in resolving the transient evolution of velocity field, especially the fluctuation quantities and turbulent statistical quantities. It is also emphasized that both approaches perform distinctly in quantifying the patterns of internal flow in different regions within the centrifugal impeller.
Species transport in a variable-density turbulent mixing layer considering stratified instability
Authors: Pei Binbin , Bai Bofeng
Published: October 2023

Mixing of miscible fluids with differing densities in turbulent mixing layers is of great importance in chemical engineering. In addition to the effect of density ratio R between two fluids, stratified instability will introduce additional complexity to turbulent mixing of species. We investigate this issue by performing direct numerical simulations of a stratified mixing layer involving two miscible fluids with R = 1, 3, and 6. We find the stronger decay of turbulence in the high-density stream in comparison with the low-density counterpart, which is attributed to the decrease in the shear rate and the increase in stratified instability. Moreover, it shows the dynamical connections between stably stratified mixing layers and wall-bounded turbulent flows, which can be supported by the hairpin vortical structures, the vertical profile of integral shear parameter S* in the low-density side (S* ≈ 10–30), and an inverse wave-number scaling for streamwise energy spectrum of velocity fluctuation. The statistical analysis of the budget of the mixture fraction variance shows that the turbulent mixing of species is significantly suppressed in the high-density side while enhanced in the low-density one, as a result of the larger reduction of turbulent production, turbulent flux, and a smaller reduction of dissipation in the high-density side. Finally, we find that the dissipation rate of the structure function of the mixture fraction variance is about four times larger than that of mixture fraction variance. These results can provide support for large eddy simulation of stratified turbulent mixing of miscible fluids with differing densities.