bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic evidence of cool plasma in quiet Sun small-scale brightenings detected by HRIEUV on board Solar Orbiter
Authors: Dolliou A. , Parenti S. , Bocchialini K.
Published: May 2024

Context. A large number of small and short-lived EUV brightenings have been detected in the quiet Sun (QS) over the past three years by the High Resolution Imager of the Extreme Ultraviolet Imager (HRIEUV) on board Solar Orbiter. It remains uncertain whether these events reach coronal temperatures and, thus, whether they directly contribute to coronal heating.

Aims. In this work, we evaluate the maximum temperature of 11 EUV brightenings in the QS through plasma diagnostics with UV/EUV spectroscopy and imaging.

Methods. We used three QS observations coordinated alongside those of HRIEUV: Spectral Imaging of the Coronal Environment (SPICE/Solar Orbiter), EUV Imaging Spectrometer (EIS/Hinode), and Atmospheric Imaging Assembly (AIA/SDO). We detected events in HRIEUV, ranging from 0.8 to 6.2 Mm in length. We then identified nine of them in SPICE and AIA, as well as three in EIS. We investigated their temporal evolution using their light curves and applied temperature diagnostics, such as the LOCI emission measure (EM) and the differential EM (DEM). We also estimated the electron density of one event identified in EIS.

Results. These events are dominated by emission of plasma at chromospheric and TR temperatures and they barely reach temperatures above 1 MK. As such, we concluded that their contribution to coronal heating is not dominant. The estimated density of one of the event is ne = (1.8 ± 1.3)×1010 cm−3.
Complexity analysis of quasi continuous level Monte Carlo
Authors: Beschle Cedric Aaron , Barth Andrea
Published: May 2024

Continuous level Monte Carlo is an unbiased, continuous version of the celebrated multilevel Monte Carlo method. The approximation level is assumed to be continuous resulting in a stochastic process describing the quantity of interest. Continuous level Monte Carlo methods allow naturally for samplewise adaptive mesh refinements, which are indicated by (goal-oriented) error estimators. The samplewise refinement levels are drawn in the estimator from an exponentially-distributed random variable. Unfortunately in practical examples this results in higher costs due to high variance in the samples. In this paper we propose a variant of continuous level Monte Carlo, where a quasi Monte Carlo sequence is utilized to “sample” the exponential random variable. We provide a complexity theorem for this novel estimator and show that this theoretically and practically results in a variance reduction of the whole estimator.
Optimization of the three-component Al-Fe-Si system composition
Authors: Andreyachshenko Violetta A. , Ibatov Marat K.
Published: May 2024

Three-component Al-Fe-Si systems with an equiatomic composition are high-strength alloys that are poorly resistant to plastic deformation. To increase the material ductility, a phase diagram of the Al-Fe-Si ternary system was constructed using ThermoCalc software. The conditions for the formation of the AL8FE2SI phase, which is an α-phase and has a hexagonal lattice, have been identified. At solidus temperatures, α-AL8FE2SI and β-AL9FE2SI2 are competitive. The conditions for the developing a single-phase region consisting of 97% α-AL8FE2SI have been identified. α-AL8FE2SI is a high-temperature phase; the system will perceive plastic deformation in the temperature range of 675–612 °C, with further phase conversion upon cooling.
Interventionelle Therapie der Lungenembolie – aktueller Stand
Authors: Ito Wulf D.
Published: May 2024

Was ist neu?

Evidenz der systemischen Lysetherapie als Standardverfahren zur Rekanalisation Die Evidenz der systemischen Lysetherapie in High- und Intermediate-High-Lungenembolien ist niedrig. Ohne rekanalisierende Maßnahmen führt die Rechtsherz-Dekompensation in High- und Intermediate-High-Risk-Lungenembolien oft zum Tod.

Kathetergestützte Techniken In den letzten Jahren wurden mehrere Systeme zur interventionellen Rekanalisation bei Lungenembolie etabliert. Wie in anderen Feldern der vaskulären Medizin sind interventionelle Rekanalisationsmethoden auch bei der Lungenembolie potenziell effektiver als die systemische Lysetherapie, unter Umgehung erhöhter Blutungsrisiken. Auch wenn bisher Ergebnisse laufender randomisierter kontrollierter Endpunktstudien noch ausstehen, sind die bisherigen Daten vielversprechend.

Die Rolle des PERT-Teams Die zunehmend komplexere Behandlung der Lungenembolie erfordert spezialisierte interdisziplinäre Behandlungsteams, sog. Pulmonary-Artery-Response-Teams (PERT-Teams) und strukturierte Behandlungsabläufe.
Selbstwirksamkeit – der Weg zur Abstinenz
Authors: Kautz Saskia
Published: May 2024

Menschen mit einer schweren Alkoholabhängigkeit weisen häufig eine mangelnde Selbstwirksamkeit auf. Sie haben sich und ihre Ziele aufgegeben, im Fokus steht nur noch der Suchtmittelkonsum. Mithilfe der pflegerisch gestützten Heavy-User-Therapie können Betroffene ihre individuellen Stärken (wieder)finden und im stationären Setting umsetzen. Dies stärkt ihre Selbstwirksamkeit und kann Rückfällen vorbeugen.
Psychosen im Kindesalter
Authors: Dißmann Steffen
Published: May 2024

Psychosen im Kindes- und Jugendalter treten häufiger auf, als allgemein angenommen wird. Beispielsweise ist hinlänglich belegt, dass die Schizophrenie meist im Jugend- und jungen Erwachsenenalter beginnt. Wir stellen die Symptome und Störungsbilder von Psychosen vor und erläutern, warum ein authentischer und komplementärer Umgang für Betroffene hilfreich ist.
Ultraschall in der Sporttraumatologie
Authors: Lerchbaumer Markus Herbert , Perschk Maximilian , Gwinner Clemens
Published: May 2024

Die Ultraschalldiagnostik umfasst zahlreiche Anwendungsmöglichkeiten in der Sporttraumatologie. Der technische Fortschritt mobiler Geräte führt zu einer zunehmenden Nutzung der Sonografie als fokussierte Erstdiagnostik. Neue Verfahren wie die Elastografie und 3D-Vaskularisation umfassen vorrangig die spezialisierte Sonografie in wenigen Fragestellungen.

Die vorliegende Übersicht soll den aktuellen Stellenwert der Sonografie in der Sporttraumatologie, ihre etablierten Anwendungsgebiete und neuen technischen Fortschritte vorstellen. Dabei wird der Ultraschall sowohl in seiner Stellung zu anderen bildgebenden Verfahren als auch als alleiniges Diagnostikum bewertet.

Ultraschall kann sowohl zur Initialdiagnostik als auch als Verlaufsbildgebung angewendet werden. Hauptanwendungsgebiete sind aktuell die Diagnostik von akuten Muskel- und Sehnenverletzungen sowie Überlastungsschäden. Insbesondere der Ausschluss struktureller Muskelverletzungen ist mit dem US an ausgewählten anatomischen Regionen suffizient zu gewährleisten. Durch die kürzlich neu publizierte Leitlinie zur Fraktursonografie wurde die klinische Evidenz in diesem Bereich gestärkt, vor allem im Vergleich zum konventionellen Röntgen sowie in der Entwicklung von Algorithmen und Standards. Der zunehmende Einsatz mobiler Ultraschallgeräte mit adäquater Bildqualität machen die Sonografie zu einer ortsunabhängigen Modalität, die auch in Trainingsstätten als bildgebende Erweiterung der klinischen Untersuchung genutzt werden kann.
Wie geht es weiter?
Authors: Lukuc Sarah
Published: May 2024

Wir brauchen eine zielgerichtete Reform. Um dies zu erreichen, sind bestimmte Maßnahmen unumgänglich –
vor allem muss die Profession Pflege einbezogen werden.
Vergleich von Trastuzumab-Biosimilar ABP 980 mit Referenz-Trastuzumab bei der neoadjuvanten Therapie von HER2-positivem Brustkrebs – Analyse eines großen universitären Brustkrebszentrums
Authors: Matovina Sabine , Engler Tobias , Volmer Lea Louise , Müller Heike , Grischke Eva-Maria , Staebler Annette , Hahn Markus , Brucker Sara Yvonne , Hartkopf Andreas Daniel
Published: May 2024

Hintergrund ABP 980 ist ein biosimilarer Antikörper von Referenz-Trastuzumab (RTZ). Ziel dieser Studie war es, die Ähnlichkeit von ABP 980 mit RTZ zu bestätigen in Bezug auf die klinische Wirksamkeit und Sicherheit in Patientinnen mit HER2-positivem Brustkrebs im Frühstadium, die sich einer neoadjuvanten Chemotherapie mit Trastuzumab unterziehen. Die Studie sollte reale klinische Bedingungen abbilden und schloss somit auch Patientinnen ein, die Pertuzumab erhielten.

Methoden Patientinnen mit HER2-positivem Brustkrebs im Frühstadium, die zwischen 12/2010 und 03/2020 in der Frauenklinik des Universitätsklinikums Tübingen, Deutschland, mindestens 4 Zyklen einer neoadjuvanten Chemotherapie (+/− Pertuzumab) in Kombination mit ABP 980 oder RTZ erhielten, wurden in diese retrospektive Analyse aufgenommen. Für die Wirksamkeitsanalyse wurden Patientinnen mit pathologischer Komplettremission (pCR = kein invasiver Tumor in der Brust und negativer Lymphknotenstatus) verglichen. Zur Beurteilung der Sicherheit von ABP 980 wurde die Anzahl an Patientinnen, die eine Minderung ihrer linksventrikulären Funktion (LVEF) von mehr als 10% aufwiesen, verglichen.

Ergebnisse Insgesamt wurden 124 Patientinnen in die Studie aufgenommen. Davon erhielten 46 (37,1 %) Frauen ABP 980, und 77 (62,9 %) Patientinnen wurden mit RTZ behandelt. Eine pCR stellte sich bei 77 (62,1 %) Patientinnen ein. Es gab keinen signifikanten Unterschied bezüglich der klinischen Wirksamkeit zwischen mit ABP 980 behandelten Patientinnen und den mit RTZ behandelten Patientinnen (die jeweiligen pCR-Raten betrugen 60,9% bzw. 62,8 %, p = 0,829), auch nicht in Bezug auf die kardiologische Sicherheit (eine LVEF-Minderung wurde bei 6,5% bzw. 2,6% der Fälle vermerkt, p = 0,274).

Schlussfolgerung Die Ähnlichkeit von ABP 980 und RTZ in einer realen klinischen Situation, die auch eine große Anzahl an mit Pertuzumab behandelten Patientinnen einschloss, konnte bestätigt werden.
Alles unter Kontrolle?
Authors: Eggeling Johanna , Kalsdorf Barbara , Schaub Dagmar , Schierholz Stefanie , Hammerl Peter , Nowak Dennis , Lange Christoph
Published: May 2024

Ein 43-jähriger Steinbrucharbeiter steht nach 16-jähriger Exposition gegenüber Quarzfeinstaub in einem deutschen Steinbruch auf der Warteliste für eine Lungentransplantation: Die Inhalation des Feinstaubs schädigte die Lunge irreversibel und begünstigte das Auftreten fulminanter mykobakterieller und mykotischer Infektionen, die bereits zur einseitigen Pneumektomie und zunehmenden respiratorischen Insuffizienz führten. Trotz regelmäßiger Überwachungen durch die Berufsgenossenschaft konnte diese dramatische Entwicklung der Silikose nicht verhindert werden.
Digitalisierung in der Migränetherapie
Authors: Lindner Diana , Holle-Lee Dagny , Scheffler Armin
Published: May 2024

Digitalisierung ist ein viel verwendetes Schlagwort in der Medizin und hat auch
die Migräne und ihre Therapie erreicht. Digitalisierung soll allerdings kein
Selbstzweck sein, sondern die Behandlung von Patienten verbessern und die Arbeit
von Behandlern erleichtern. Dieser Artikel beschäftigt sich mit den Bereichen
der Migränemedizin, wo dies heute schon so ist bzw. zukünftig so sein kann.
The Impact of Intraoperative Vasopressor Use and Fluid Status on Flap Survival in Traumatic Lower Extremity Reconstruction
Authors: Roohani Idean , Moshal Tayla , Boudiab Elizabeth M. , Stanton Eloise W. , Zachary Paige , Lo Jessica , Carey Joseph N. , Daar David A.
Published: May 2024

Background Historically, the use of intraoperative vasopressors during free flap lower extremity (LE) reconstruction has been proposed to adversely affect flap survival due to concerns about compromising flap perfusion. This study aims to analyze the impact of intraoperative vasopressor use and fluid administration on postoperative outcomes in patients undergoing traumatic LE reconstruction.

Methods Patients who underwent LE free flap reconstruction between 2015 and 2023 at a Level I Trauma Center were retrospectively reviewed. Statistical analysis was conducted to evaluate the association between vasopressor use and intraoperative fluids with partial/complete flap necrosis, as well as the differential effect of vasopressor use on flap outcomes based on varying fluid levels.

Results A total of 105 LE flaps were performed over 8 years. Vasopressors were administered intraoperatively to 19 (18.0%) cases. Overall flap survival and limb salvage rates were 97.1 and 93.3%, respectively. Intraoperative vasopressor use decreased the overall risk of postoperative flap necrosis (OR 0.00005, 95% CI [9.11 × 10−9–0.285], p = 0.025), while a lower net fluid balance increased the risk of this outcome (OR 0.9985, 95% CI [0.9975–0.9996], p = 0.007). Further interaction analysis revealed that vasopressor use increased the risk of flap necrosis in settings with a higher net fluid balance (OR 1.0032, 95% CI [1.0008–1.0056], p-interaction =0.010).

Conclusion This study demonstrated that intraoperative vasopressor use and adequate fluid status may be beneficial in improving flap outcomes in LE reconstruction. Vasopressor use with adequate fluid management can optimize hemodynamic stability when necessary during traumatic LE microvascular reconstruction without concern for increased risk of flap ischemia.
Upper Extremity Diaphyseal Osseous Gap Reconstruction with Free Vascularized Bone Flaps: A Scoping Review
Authors: Naga Hani I. , Kim Joshua , Dunworth Kristina , Oleck Nicholas , Emovon Emmanuel , Graton Margaret , Mithani Suhail K.
Published: May 2024

Background Reconstruction of upper extremity osseous diaphyseal defects often requires complex reconstructions. In this study, we characterized and summarized the available literature on free vascularized bone flap (VBF) reconstruction for upper extremity diaphyseal defects.

Methods A scoping review using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews was conducted. A literature search of major electronic databases was conducted to identify journal articles relating to the management of VBF reconstruction of upper limb long bone defects. Articles with patient-level data were included. Descriptive statistics were performed using Python.

Results Overall, 364 patients were included in this study. The most common indications for VBFs included atrophic nonunion (125, 34.3%), postoncologic resection (125, 34.3%), septic nonunion (56, 15.4%), and trauma (36, 9.9%). Mean defect size was 8.53 ± 5.14 cm. A total of 67 (18.4%) cases had defects < 6 cm, and 166 cases (45.6%) had defects > 6 cm. The fibula was the most utilized VBF (272, 74.73%), followed by the medial femoral condyle flap (69, 18.96%). Overall, primary union rate was 87.1%. Subsequent flap fracture rate was 3.3%. There were only two (0.6%) VBF losses reported in the included cases, and donor-site complications were similarly rare (17, 4.7%).

Conclusion VBF reconstruction is often utilized for postoncologic defects and recalcitrant nonunions. The fibula is the most utilized VBF, but the medial femoral condyle flap is used frequently for smaller defects. VBF reconstruction demonstrates high union rates and low flap fracture rate across indications.
Perceptions of Surgical Drains among Breast Reconstruction Patients and Health Care Staff: A Qualitative Survey Study
Authors: Tian William M. , Rames Jess D. , Schroeder Brooke E. , Dunworth Kristina , Yi Victoria N. , Tran Melissa , Gallagher Jennifer , Bachelder Robin , Hollenbeck Scott T.
Published: May 2024

Background Surgical drains are a key component for recovery in breast reconstruction procedures. However, they are often cumbersome and carry a risk of infection with prolonged use. We aimed to develop a more thorough understanding of patient and health care provider perspectives on surgical drains, to inform future efforts in improving the breast reconstruction patient experience.

Methods Twenty-nine breast reconstruction patients and eight plastic surgery providers were recruited to complete surveys focused on surgical drains. Likert scales ranging from 1 to 5 were developed to gauge how bothersome drains felt, as well as concern for infection. Ordinal variable and categorical multiple-choice analyses were applied as appropriate.

Results Fifteen (51.7%) patients underwent implant-based breast reconstruction, and 14 (48.3%) patients underwent autologous breast reconstruction. The most common duration of drain placement was 2 weeks (N = 13). The surgical site infection (SSI) rate requiring antibiotics was 28% (N = 8). On a scale of 1 to 5, both patients (median = 3) and providers (median = 2.5) viewed drains as bothersome. Patients were “frequently” concerned about infection risk (median = 3). Other high-frequency patient concerns included general pain and discomfort.

Conclusion Surgical drains are a common component of breast reconstruction procedures and are viewed as cumbersome by both patients and providers. Patients expressed concerns about drain site pain, discomfort, and tugging on clothing. Patients and providers both believed that drains could contribute to SSI. Overall, these data provide insight to drive future improvements in the patient drain experience.
Radical Allylation of Aldehydes with Allenes by Photoredox Cobalt and Chromium Dual Catalysis
Authors: Shi Lei , Li Haoyu , Wang Xin , Cao Renxu , Qi Xuehan , Hao Erjun
Published: May 2024

A dual cobalt and chromium photoredox-catalyzed allylation of aldehydes with allenes through a photo metal-hydride atom transfer (MHAT) process has been developed to yield homoallylic alcohols with exceptional diastereoselective control. This sustainable and efficient method holds significant promise for applications in the synthesis of valuable organic compounds.
Medialização do feixe neurovascular poplíteo e rotação axial do retalho para evitar o impacto ósseo na plastia de inversão tibial: Relato de caso
Authors: Medellin Rincon Manuel Ricardo , Gomez-Ricaurte Oscar Fernando , Riveros-Riveros Hermann Alfredo , Sambri Andrea
Published: May 2024

Um paciente do sexo masculino, de 33 anos, apresentou osteomielite crônica do fêmur distal com perda óssea maciça após fratura exposta de grau 3b. Após vários tratamentos ineficazes para erradicar a infecção, foi realizado um procedimento de aumento da tíbia para proporcionar um coto estável e funcional. Para evitar problemas neurovasculares, os vasos poplíteos e o nervo ciático foram movidos em sentido medial e o retalho foi rotacionado externamente para diminuição do colapso. A evolução após a cirurgia foi satisfatória; não houve claudicação vascular ou neurológica, e o paciente pôde usar prótese externa após a cicatrização do retalho. A plastia tibial é uma técnica reconstrutiva raramente descrita, que pode aumentar o comprimento dos cotos. A liberação e medialização dos vasos poplíteos, com rotação axial do retalho, pode prevenir o desenvolvimento de impacto neurovascular.
Design, Synthesis, and Evaluation of Novel Cryptotanshinone Derivatives for Activity against Triple-Negative Breast Cancer
Authors: Liu Siyu , Zhang Panpan , Sun Qingyan
Published: May 2024

Triple-negative breast cancer (TNBC) can be difficult to treat because of resistance to existing therapeutic agents. Our prior studies revealed the inhibitory effect of the natural product cryptotanshinone (CTS) on the proliferation of TNBC cells; however, its clinical application was prevented due to its low water solubility and activity. This study aimed to synthesize derivatives of CTS with enhanced potency and water solubility. The structure of CTS was modified by adding amino acid side chains, which were derived into phosphonium salts. The derivatives were immersed in phosphate-buffered saline (PBS) to assess their water solubility. The antitumor effects of the derivatives against MDA-MB-231 breast cancer cells were assessed by evaluating their roles in regulating cell proliferation, cell apoptosis, and cell-cycle arrest using cell counting kit-8 (CCK-8), flow cytometry, and calcein-AM/propidium iodide assay, respectively. In this work, a total of 29 derivatives of CTS were synthesized, of which the tricyclohexylphosphine derivatives C4-2 and C5-2 were highly soluble in PBS, with 790- and 450-fold higher than that of CTS, respectively, and at the same time, the antitumor activities of C4-2 and C5-2 were also enhanced, with two- and fourfold higher than that of CTS, respectively. Further studies revealed that the compounds may inhibit the proliferation of MDA-MB-231 by inducing cellular arrest in the G2/M phase. These findings provided preliminary data for the mechanisms of CTS and its derivatives in blocking TNBC and suggested C4-2 and C5-2 as potential agents for the treatment of the disease in the future.
The Role of Anti-Müllerian Hormone in Ovarian Function
Authors: Yildiz Sena , Moolhuijsen Loes M.E. , Visser Jenny A.
Published: May 2024

Anti-Müllerian hormone (AMH) is a member of the transforming growth factor β (TGFβ) superfamily, whose actions are restricted to the endocrine-reproductive system. Initially known for its role in male sex differentiation, AMH plays a role in the ovary, acting as a gatekeeper in folliculogenesis by regulating the rate of recruitment and growth of follicles. In the ovary, AMH is predominantly expressed by granulosa cells of preantral and antral follicles (i.e., post primordial follicle recruitment and prior to follicle-stimulating hormone (FSH) selection). AMH signals through a BMP-like signaling pathway in a manner distinct from other TGFβ family members. In this review, the latest insights in AMH processing, signaling, its regulation of spatial and temporal expression pattern, and functioning in folliculogenesis are summarized. In addition, effects of AMH variants on ovarian function are reviewed.
Delayed-Interval Delivery in Multiple Pregnancy: A Single-Center Experience of Five Cases
Authors: Gadeer Roaa Hassan , Alhinai Ahlam , Fung-Kee-Fung Karen , Werlang Ana
Published: May 2024

Objectives To describe the obstetric management and perinatal outcomes in multiple pregnancies with delayed-interval delivery (DID) of the cotwin in a tertiary hospital.

Methods This is a retrospective chart review of all cases of DID between December 2021 and 2022 at The Ottawa Hospital. Five cases of DID were identified and reviewed to obtain information on obstetric management and maternal–neonatal outcomes. We included eligible twins and triplets. No multiples were excluded. We obtained ethics approval for this case series.

Results Four sets of dichorionic diamniotic twins and one trichorionic triamniotic triplet were included. Our patients were admitted between 173/7 and 215/7 weeks of gestation. We achieved an interval delivery range between 1 and 36 days. Four out of six multiples did not survive in DID. The two surviving newborns were born at 230/7 and 232/7, stayed in the neonatal intensive care unit (NICU) for 111 and 131 days, discharged with a weight of 3,594 and 2,743 g, respectively. All DID cases were delivered spontaneously except for two patients that required augmentation due to maternal sepsis.

Conclusion Despite the high risk of maternal, fetal, and neonatal morbidity and mortality, if delivery of the first twin occurs before 20 gestational weeks, DID could be considered in selected cases to improve outcomes for the cotwin.
Family communication patterns, self-efficacy, and adolescent online prosocial behavior: a moderated mediation model
Authors: Zhan Weizhen , You Zhenwu
Published: May 2024

As technology has been developing by leaps and bounds, concerns regarding adolescent online behavioral patterns have garnered significant attention. Nevertheless, current research exhibits limitations in both perspective and depth. Consequently, this study introduces a moderated mediation model to investigate whether the mediating effect of self-efficacy and the moderating effect of emotional regulation strategies are valid in the relationship between family communication patterns and adolescent online prosocial behavior. A questionnaire survey encompassing 1183 adolescents across 12 schools in three cities of mainland China was conducted. The findings reveal that conversation orientation contributes to the augmentation of adolescents’ self-efficacy and online prosocial behavior, whereas conformity orientation follows a reversed trend. Furthermore, self-efficacy serves as a mediator in the relationship between conversation orientation and conformity orientation, influencing adolescent online prosocial behavior in both positive and negative manners. Additionally, this study underscores the significance of emotion regulation strategies; cognitive reappraisal not only reinforces the positive effects of conversation orientation, but also mitigates the adverse effects of conformity orientation, while expressive suppression demonstrates the inverse effect. This research yields a comprehensive and insightful understanding of adolescent online prosocial behavior, furnishing a valuable theoretical foundation for future research and practice in family education.
A high resolution dilatometer using optical fiber interferometer
Authors: Qin Xin , Cao Guoxin , Geng Mengqiao , Liu Shengchun , Liu Yang
Published: May 2024

We introduce a high-performance differential dilatometer based on an all-fiber Michelson interferometer at cryogenic temperature with 10−10 resolution in δL/L. It resolves the linear thermal expansion coefficient by measuring the oscillating changes of sample thickness and sample temperature with the interferometer and in situ thermometer, respectively. By measuring the linear thermal expansion coefficient α near the antiferromagnetic transition region of BaFe2As2 as a demonstration, we show that our dilatometer is able to measure thin samples with sub-pm-level length change resolution and mK-level temperature resolution. Despite the residual background thermal expansion of a few nm/K in the measurement results, our new dilatometer is still a powerful tool for the study of phase transition in condensed matter physics, especially has significant advantages in fragile materials with sub-100 μm thickness and being integrated with multiple synchronous measurements and tuning thanks to its extremely high resolution and contactless nature. The prototype design of this setup can be further improved in many aspects for specific applications.
Revised Parameters for the IAPWS Formulation for the Ionization Constant of Water Over a Wide Range of Temperatures and Densities, Including Near-Critical Conditions
Authors: Arcis Hugues , Bachet Martin , Dickinson Shirley , Duncanson Iain , Eaker Richard W. , Jarvis Jennifer , Johnson Ken , Lee Christopher A. , Lord Fred , Marks Chuck , Tremaine Peter R.
Published: May 2024

The literature database for the ionization constant of water, pKw, has been critically reevaluated to include new accurate flow conductivity data recently reported at near-critical and supercritical conditions. Recently published equations to express the limiting conductivity of fully ionized water were used to correct the conductivity data and yield more accurate pKw values at water densities below 0.6 g cm−3. The ability of the functional forms adopted by the 1980 and 2006 International Association for the Properties of Water and Steam releases to fit the near-critical and supercritical data was tested. Revised parameters for the 2006 “simple” function were derived to improve the accuracy of the model under these conditions. The data fitting procedure made use of estimated standard uncertainties as well as a weighting parameter for each dataset to minimize potential bias due to the very large amount of flow conductivity data now available. Calculations based on the revised formulation were found to be consistent with independent high-temperature data measured using calorimetry and density methods. The revised equation is accurate to within the estimated standard uncertainty limits over the range 0–1000 °C, p = 0–1000 MPa.
Experimental investigation on gap resonance between two floating vessels
Authors: Vineesh P. , Sriram V.
Published: May 2024

This paper explains the influence of gap resonance phenomena in floating vessels having unequal draughts. Two separate model configurations are considered here: one is a vessel having a shallow draught at the weather side (SW), and the other is a deep draught vessel that comes at the weather side. An experimental investigation was carried out in beam sea conditions, where the vessel could only move freely in the heave and roll directions. By beam sea, we mean the incident waves come at a right angle to the broadside of the vessels. Regular wave tests reveal that even though only a slight difference in the gap resonance frequency is observed for the two configurations, the wave amplification at resonance is 57% higher for SW. The reason for this behavior is explained using the instantaneous velocity and vorticity obtained from the particle image velocimetry analysis for a selected test case. Furthermore, the turbulent characteristics of the flow inside the gap for the configurations are compared at different time instances. The horizontal force acting on the vessels and motions (heave and roll) of the vessels in the beam sea condition are also reported in the study.
The investigation on the flow characteristics during the continuous development of the tip leakage vortex cavitation in an axial pump-jet propulsion
Authors: Xu Shun , Xiong Yongliang , Tang Fangping , Li Guibin , Long Xinping , Ji Bin , Huang Renfang
Published: May 2024

The continuous deterioration and development of tip leakage vortex (TLV) cavitation in the pump-jet propulsion significantly affect propulsion performance and operational stability. Larger eddy simulation and cavitation tunnel experiment are utilized to investigate the temporal and spatial evolution characteristics of TLV cavitation under varying cavitation conditions. The results reveal that the continuous development of TLV cavitation prompts the TLV to gradually move away from the blade suction surface due to increasing pressure difference at the blade tip surface. Furthermore, the development of TLV cavitation amplifies the effect of the radial outward Coriolis force and makes the TLV even more unstable. Under the influence of the tip leakage flow, primary generation of turbulent kinetic energy (TKE) persistently migrates to the TLV core center and subsequently travels downstream. Despite the large magnitude of TKE that occurs at the TLV core center, the TKE generation remains low. With the inception of TLV cavitation, the transport of TKE between the TLV core center and the surrounding flow gradually intensifies, followed by a subsequent weakening of this transport effect. It increases again as the breakdown of TLV becomes more severe.
Inferring bifurcation diagrams with transformers
Authors: Zhornyak Lyra , Hsieh M. Ani , Forgoston Eric
Published: May 2024

The construction of bifurcation diagrams is an essential component of understanding nonlinear dynamical systems. The task can be challenging when one knows the equations of the dynamical system and becomes much more difficult if only the underlying data associated with the system are available. In this work, we present a transformer-based method to directly estimate the bifurcation diagram using only noisy data associated with an arbitrary dynamical system. By splitting a bifurcation diagram into segments at bifurcation points, the transformer is trained to simultaneously predict how many segments are present and to minimize the loss with respect to the predicted position, shape, and asymptotic stability of each predicted segment. The trained model is shown, both quantitatively and qualitatively, to reliably estimate the structure of the bifurcation diagram for arbitrarily generated one- and two-dimensional systems experiencing a codimension-one bifurcation with as few as 30 trajectories. We show that the method is robust to noise in both the state variable and the system parameter.
A numerical study of electron-magnetohydrodynamics tearing modes in parameter ranges of experimental interest
Authors: Betar H. , Del Sarto D. , Ghizzo A. , Brochard F. , Zarzoso D.
Published: May 2024

We perform a numerical study of the linear dynamics of tearing modes in slab incompressible electron-magnetohydrodynamics (EMHD) by considering some parameter ranges, which can be of interest for laboratory plasmas (e.g., helicon devices) or for astrophysics (e.g., solar-wind turbulence). To this purpose, several non-ideal effects are simultaneously retained (finite electron inertia, resistivity, and electron viscosity), and we make distinction between the dissipation coefficients in the direction parallel and perpendicular to the guide field. We thus identify some new reconnection regimes, characterized by a departure from the customary monotonic power-law scalings of the growth rates with respect to the non-ideal parameters. The results here presented can provide a useful indication for future studies of EMHD regimes relevant to experiments and for extensions of the EMHD tearing mode modeling to more complete regimes including kinetic effects (e.g., “electron-only” reconnection in kinetic regimes).
Vibration-triggered spreading of nanofluid drops
Authors: Fusco Schon , Liu Lingyue , Cabrerizo-Vílchez Miguel Ángel , Koos Erin , Rodríguez-Valverde Miguel Ángel
Published: May 2024

This study explores the effects of nanoparticles on the dynamics of drop spreading under external vibration, presenting an advance in the understanding of nanofluid behavior on vibrating substrates. This work introduces insights into nanoparticle-mediated drop spreading, offering implications for improving particulate coatings, mini-mixers, and particle segregation technologies. By employing a twofold approach that combines oscillating drop dynamics with internal flow pattern analysis, we find how even small concentrations of hydrophilic or hydrophobized silica nanoparticles inside water sessile droplets significantly alter the spreading process on silanized glass surfaces. Our study allows distinct drop spreading regimes to be identified based on nanoparticle concentration and vibration amplitude, for both hydrophilic and hydrophobized nanoparticles. Through a comprehensive analysis, we demonstrate that the vibration-triggered spreading of nanofluids can lead to a stable and controlled manipulation of complex liquids.
In-plane thermal conductivity of hexagonal boron nitride from 2D to 3D
Authors: Tang Jialin , Zheng Jiongzhi , Song Xiaohan , Cheng Lin , Guo Ruiqiang
Published: May 2024

The in-plane thermal conductivity of hexagonal boron nitride (h-BN) with varying thicknesses is a key property that affects the performance of various applications from electronics to optoelectronics. However, the transition of the thermal conductivity from two-dimensional (2D) to three-dimensional (3D) h-BN remains elusive. To answer this question, we have developed a machine learning interatomic potential within the neuroevolution potential (NEP) framework for h-BN, achieving a high accuracy akin to ab initio calculations in predicting its thermal conductivity and phonon transport from monolayer to multilayers and bulk. Utilizing molecular dynamics simulations based on the NEP, we predict the thermal conductivity of h-BN with a thickness up to ∼100 nm, demonstrating that its thermal conductivity quickly decreases from the monolayer and saturates to the bulk value above four layers. The saturation of its thermal conductivity is attributed to the little change in phonon group velocity and lifetime as the thickness increases beyond four layers. In particular, the weak thickness dependence of phonon lifetime in h-BN with a nanoscale thickness results from its extremely high phonon focusing along the in-plane direction. This research bridges the knowledge gap of phonon transport between 2D and 3D h-BN and will benefit the thermal design and performance optimization of relevant applications.
Inverse design of the radiation temperature for indirect laser-driven equation-of-state measurement
Authors: Liao Lingrui , Shen Jingxiang , Sun Liang , Mo Chongjie , Kang Wei
Published: May 2024

The theoretical design for the time profile of radiation temperature plays an important role in indirect laser-driven equation-of-state measurement, which severely relies on a large number of radiation hydrodynamic simulations. In this work, we provide a concise data-driven method for optimizing the radiation temperature profile, which combines a time-varying Volterra model with an improvement achieved by data generation via radiation hydrodynamic simulations utilizing random perturbations in a skew normal distribution as inputs. We find that the time-varying Volterra model can be used to investigate the time-dependent relationship between the radiation temperature and the key physical quantities of interest, such as shock-wave velocity and ablation drive pressure. With this method, we realize the inverse designs of the radiation temperature profiles for planar dynamic shock and ramp compressions according to the desired shock-wave velocity and drive pressure, respectively, which shows the advantage of practical application in experiments.
Tip-leakage-flow excited unsteadiness and associated control
Authors: Liu Yabin , Wang Zhong-Nan , Tan Lei , Tucker Paul Gary , Möller Felix M.
Published: May 2024

Tip leakage flow in turbomachinery inherently generates intense unsteady features, named self-excited unsteadiness, which significantly affects the operating stability, aerodynamic efficiency, and noise but has not been well understood. A zonalized large eddy simulation is employed for a linear cascade, with wall-modeled large eddy simulation active only in the tip region. The simulation is well validated with advantages demonstrated for effectively reducing the computational cost while maintaining an equivalent prediction accuracy in the region of interest. The time-averaged and spatial-spectral characteristics of tip leakage vortex (TLV) structures are systematically discussed. The self-excited unsteady processes of TLV include the tip gap separation, the tip leakage and jet-mainstream interaction, the primary tip leakage vortex (PTLV) wandering motion, and the induced separation near end wall. The Spectral Proper Orthogonal Decomposition (SPOD) is used to examine the dominant frequencies and their coherent structures. It is found that these unsteady features change from a single high frequency to multiple lower frequencies due to the PTLV breakdown. The SPOD and correlation analyses reveal that the self-excited unsteadiness originates initially from unsteady vortex separation in the tip gap and is then fed by the interactions between the tip leakage jet and mainstream. The associated unsteady fluctuations are convected along the tip leakage jet trajectory, causing the wandering motion of PTLV core. Based on the revealed unsteadiness sources, a micro-offset tip design is proposed and shown to be an effective solution to reducing the tip flow unsteadiness. This work improves the understanding of tip-leakage-flow dynamics and informs the control of the associated unsteady fluid oscillation and noise.
High electron mobility in heavily sulfur-doped 4H-SiC
Authors: Kaneko Mitsuaki , Matsuoka Taiga , Kimoto Tsunenobu
Published: May 2024

The Hall electron mobility in sulfur-doped 4H-SiC over a wide range of S concentration was investigated. Sulfur (S) works as a double donor in SiC. The electron concentration in the S+-implanted layers saturates when the S concentration exceeds 1×1018 cm−3 and the net donor concentration of the S+-implanted layer with S concentration of 1×1019 cm−3 is 4×1018 cm−3, indicating that the solubility or activation limit of S+-implanted SiC is about 2×1018 cm−3. The S+-implanted SiC with a S concentration of 1×1018 cm−3 exhibits an electron mobility of 598 cm2/V s, which is more than twice as high as that in N-doped SiC with the same doping concentration (268 cm2/V s). The temperature dependence of the electron mobility in S+-implanted SiC is reproduced in the wide temperature range by the calculation of the electron mobility adopting the helium atom model for neutral-impurity scattering.
Vibrationally driven particle formations in fluid systems with bimodal thermal inhomogeneities
Authors: Santhosh Balagopal Manayil , Lappa Marcello
Published: May 2024

This study builds on and extends an earlier investigation [Santhosh and Lappa, “On the relationship between solid particle attractors and thermal inhomogeneities in vibrationally-driven fluid-particle systems,” Phys. Fluids 35(10), 103316 (2023)]. As the predecessor work, it can be placed in a wider theoretical context, that is, a line of inquiry started a decade ago [Lappa, “The patterning behavior and accumulation of spherical particles in a vibrated non-isothermal liquid,” Phys. Fluids 26(9), 093301 (2014)] about the surprising ability of high-frequency vibrations imposed on a non-isothermal fluid containing dispersed solid particles to support the self-emergence of ordered particle structures. Here, the non-trivial relationship between the number and shape of the particle formations and the nature of the thermal conditions along the boundary of the fluid container is further explored by probing in detail the role of thermal spot multiplicity. The problem is approached in the framework of a hybrid Eulerian–Lagrangian numerical approach. The results indicate that completely new morphologies become accessible, which are not possible when only two walls are thermally active. Moreover, on increasing the angle ϕ formed by vibrations with the direction perpendicular to the adiabatic walls of the cavity, the compact surfaces formed by particles for ϕ = 0° are taken over by more complex formations, which give the observer the illusion of a flexible fabric formed by the intersection of many independent filamentary structures.
Adaptive detached eddy simulation of turbulent combustion with the subgrid dissipation concept
Authors: Liu Haochen , Yin Zifei , Liu Hong
Published: May 2024

Detached eddy simulation has become a widely used method in eddy simulations due to its balance between cost and accuracy. The recently developed subgrid dissipation concept (SDC) combustion model [Liu et al., “On the subgrid dissipation concept for large eddy simulation of turbulent combustion,” Combust. Flame 258, 113099 (2023)] is found to be more reasonable and accurate than the conventional eddy dissipation concept model in large eddy simulation (LES). In this paper, the SDC model is adapted to the ℓ2-ω adaptive detached eddy simulation framework, named DES-SDC. The required key quantities, including the fine structure mass fraction and dissipation rate, are appropriately blended across Reynolds-averaged Navier–Stokes and LES regions. The DES-SDC approach is validated using premixed bluff body stabilized flame, non-premixed swirl flame, and premixed swirl flame with complex geometry. It is much more tolerant to coarse mesh resolution than pure LES, yet it preserves the capability of resolving the key unsteady feature critical for the combustion process, as it is designed to be. The DES-SDC approach is relatively insensitive to the grid resolution. The present research provides a promising approach for accurately simulating practical unsteady turbulent combustion problems at an affordable computational cost.
On the power-law exponent of multimode Richtmyer–Meshkov turbulent mixing width
Authors: Li Qi-xiang , Zhang You-sheng , Ruan Yu-cang
Published: May 2024

Turbulent mixing induced by the Richtmyer–Meshkov (RM) instability occurs extensively in natural phenomena and engineering applications. Among the physical quantities characterizing the RM turbulent mixing, the mixing width has prominent importance. The total mixing width h can be divided into the spike mixing zone width hs and the bubble mixing zone width hb. For multimode perturbed RM problems that commonly occur in engineering practice, early instability develops rapidly into the self-similar regime. In this regime, it is widely accepted that hs,bt∼tθs,b, where t is the time and θs,b is the power-law exponent. However, this scaling law is associated with two open questions. (1) How should a reasonable reference interface be selected to segment h into hs and hb? (2) Are the resulting θs and θb equal to each other or not? To answer these two questions, in this study, we propose a general definition of reference interface based on the position corresponding to any fixed value of either the mass fraction, volume fraction, or density. Under this definition, the invariance of fraction and density profiles by self-similar transformation leads to hs,bt∼tθs,b with θs=θb. The general definition covers those provided in linear electronic motor experiment [Dimonte and Schneider, “Density ratio dependence of Rayleigh–Taylor mixing for sustained and impulsive acceleration histories,” Phys. Fluids 12, 304–312 (2000)] and shock tube experiment [Krivets et al., “Turbulent mixing induced by Richtmyer-Meshkov instability,” AIP Conf. Proc. 1793, 150003 (2017)]. Moreover, these two definitions are proved to be, respectively, special cases of newly proposed general definition. Finally, it is deduced that θs≠θb observed in high-density ratio experiments is possibly because the turbulent mixing has not entered a self-similar regime. Compared to the low-density ratio cases, mixing of high-density ratio is much more difficult to enter the self-similar regime.
Channel width-dependent viscosity and slip length in nanoslits and effect of surface wettability
Authors: Tsao Yu-Hao , Liao Ying-Chih , Tsao Heng-Kwong
Published: May 2024

The channel width-dependent behaviors of viscosity (μ) and slip length (ls) in nanoslits are investigated using many-body dissipative particle dynamics simulation in both Poiseuille and Couette flow systems. In both systems, the viscosity and slip length increase as the channel width (w) grows in smaller channels, while they reach bulk values in larger channels. Moreover, as the surface wettability decreases, the slip length is found to increase, while the viscosity remains the same. The channel width-dependent behavior in nanoslits can be explained by the unique structure of the confined fluid. As the channel width narrows, the uniform density profile in the central region diminishes, and an oscillation pattern appears throughout the system. The change in the microstructure with the channel width alters friction between layers of fluid in laminar flow and fluid-solid friction, leading to a w-dependent μ and ls. Nonetheless, the alteration of surface wettability influences only fluid–solid interactions but not the friction between layers of fluid.
Probabilistic microkinetic modeling: Species balance equations for a catalyst surface containing multiple short-range order parameters to capture spatial correlations
Authors: Kumar Aditya , Chatterjee Abhijit
Published: May 2024

Adsorbed molecules on a catalyst almost always arrange themselves in a manner that is far from perfectly random, which gives rise to spatial correlations. These correlations are a result of the interactions between the adsorbed species (adspecies) as well as elementary processes such as diffusion and reaction events that shape the adspecies arrangements. Despite their importance, spatial correlations are usually ignored while writing species balance equations for the modeling of heterogeneous catalytic systems. Recently, we have introduced a probabilistic microkinetic modeling (p-MKM) framework that aims at incorporating spatial correlations in the form of a short-ranged order (SRO) parameter into species balance equations. Here, we extend the approach to catalytic systems of higher complexity, namely, longer interactions and multiple species. This is made possible by including multiple pair probabilities in the p-MKM model for the first time. The interplay between different SRO parameters is probed. An important consideration is how many pair probabilities should be included to capture the underlying complexity with sufficient accuracy.