bluuebunny/crossref_metadata_2025 huggingface dataset:
Neue Aspekte zur Therapie des Dravet-Syndroms
Authors: Schubert-Bast Susanne , Strzelczyk Adam
Published: November 2022

Das Dravet-Syndrom ist gekennzeichnet durch eine schwer behandelbare Epilepsie und assoziierte Komorbiditäten. Nun stehen neben Stiripentol mit Cannabidiol und Fenfluramin zwei neue und spezifische Therapieoptionen zur Verfügung. In diesem Beitrag erfolgt ein Überblick über die gebräuchlichsten und neuen Antikonvulsiva, deren Wirkung, Sicherheitsprofil sowie die potenziellen Interaktionen.
Genetische Aspekte kindlicher Epilepsiesyndrome
Authors: Syrbe Steffen
Published: November 2022

Kindliche Epilepsiesyndrome sind Erkrankungen mit früh beginnenden epileptischen Anfällen und assoziierten Störungen der motorischen und kognitiven Entwicklung. Die Klassifikation der Epilepsiesyndrome nach elektroklinischen Kriterien bildet die Grundlage für die Therapie und die prognostische Einschätzung. Zunehmend kann eine steigende Zahl monogenen Ursachen zugeordnet werden. Die Kenntnis des genetischen Hintergrundes erlaubt so eine Einteilung nach pathophysiologischen zellulären Ursachen, kann den diagnostischen Prozess erleichtern und die Therapieentscheidung zukünftig unterstützen.
Kognition bei Epilepsien im Kindes- und Jugendalter
Authors: Borggraefe Ingo , Sorg Anna Lisa , Cornell Sonia
Published: November 2022

Kognitive Einschränkungen sind bei etwa jedem fünften Kind mit einer Epilepsie vorhanden. Ein besonders hohes Risiko besteht bei früher Epilepsiemanifestation. Die Ursache der Epilepsie beeinflusst neben anderen Faktoren das Ausmaß der kognitiven Einschränkungen am stärksten. Die Erkennung von kognitiven Einschränkungen bei Kindern mit Epilepsie kann Auswirkungen auf entsprechende Förderkonzepte und Lebenswege für die betroffenen Kinder haben. Ferner muss erkannt werden, ob die medikamentöse Behandlung der Anfälle zu einer eingeschränkten kognitiven Leistungsfähigkeit beiträgt. In einigen Fällen können frühzeitige epilepsiechirurgische Eingriffe, sofern der Patient dafür infrage kommt, einen kognitiven Abbau aufhalten.
Severe Maternal Morbidity in Twins
Authors: Binstock Anna , Bodnar Lisa M. , Himes Katherine P.
Published: November 2022

Objective While twin gestations are at increased risk of severe maternal morbidity (SMM), there is limited information about timing and causes of SMM in twins. Furthermore, existing data rely on screening definitions of SMM because a gold standard approach requires chart review. We sought to determine the timing and cause of SMM in twins using a gold standard definition outlined by the American College of Obstetricians and Gynecologists (ACOG).

Study Design We used a perinatal database to identify all twin deliveries from 1998 to 2013 at a single academic medical center (n = 2,367). Deliveries were classified as screen positive for SMM if they met any of the following criteria: (1) one of the Centers for Disease Control and Prevention (CDC) International Classification of Diseases Ninth Revision diagnosis and procedure codes for SMM; (2) a prolonged postpartum length of stay (>3 standard deviations beyond mean length of stay by mode of delivery); or (3) maternal intensive care unit admission. We identified true cases of SMM through medical record review of all screen-positive deliveries using the definition of SMM outlined in the ACOG Obstetric Care Consensus. We also determined cause and timing of SMM.

Results A total of 165 (7%) of twin deliveries screened positive for SMM. After chart review of all screen-positive cases, 2.4% (n = 56) were classified as a true case of SMM using the ACOG definition for a positive predictive value of 34%. The majority of SMM occurred postpartum (65%). Hemorrhage was the most common cause of SMM, followed by hypertensive and pulmonary etiologies.

Conclusion Commonly used approaches to screen for SMM perform poorly in twins. This has important implications for quality initiatives and epidemiologic studies that rely on screening definitions of maternal morbidity. Our study demonstrates that the immediate postpartum period is a critical time for maternal health among women with twin pregnancies.

Key Points
Understanding the Factors that Determine a Fellow's Choice in Neonatal–Perinatal Medicine and How They Establish Their Rank List
Authors: Kane Sara K. , Palmer Megan M. , Slaven James E. , Niehaus Jason Z.
Published: November 2022

Objective Little is known about why neonatology fellows pick the fellowship program they do. Understanding why fellows choose neonatology and rank their programs would be of benefit to program leadership and to other applicants.

Study Design This was a survey study sent to current neonatology fellows in the United States between September 2020 and October 2020, and were asked to rank their choices on a Likert scale. Respondents were also able to give free text responses to open-ended questions.

Results The most important factor fellows state for choosing their program was location, with multiple reasons given. There were significant differences in how certain subgroups ranked programs.

Conclusion Location of the fellowship program is the most important factor for fellows. There are differences within subgroups of fellows on how they rank their fellowship program. Fellowship directors can use this information to better inform selections on who to interview and how to rank fellows.

Key Points
Histological Investigation of the Cleaning Effectiveness of Different Biomechanic Processes of Isthmus in Lower Molars
Authors: Aydın Rabia N. , Gençoğlu Nimet
Published: November 2022

Objectives This study aimed to evaluate the efficacy of different instruments (Hyflex, ROTATE, and hand files) and irrigation methods (EndoUltra, EndoActivator, and side-perforated syringe) in the mesial root canal of a mandibular first molar with isthmuses.

Materials and Methods Sixty-three mandibular molar teeth with isthmus were selected using cone beam computed tomography (CBCT) images. The root canals were instrumented with Hyflex, ROTATE, or hand files (21 of each) and three of each as control group and the specimens were embedded in silicone blocks. Final irrigation was performed with the perforated syringe or ultrasonic (EndoUltra) or sonic irrigation (EndoActivator). All canals were irrigated using 5.25% NaOCl solution (15 mL). Then, the roots were stained with hematoxylin–eosin, and specimens were sliced for histologic evaluation. The isthmus regions (2.7, 3, 4.7, and 5 mm from the apex) were analyzed, and the percentage of debris was calculated.

Statistical Analysis All data were statistically analyzed using one-way analysis of variance and Tukey's tests.

Results Both Hyflex and ROTATE groups showed less debris compared with the hand instrument group (P < 0.05). When irrigation methods were compared, EndoUltra showed the least, followed by EndoActivator and perforated needle irrigation having the maximum debris (p < 0.05). When sections were compared, the maximum debris was found in the apical section and the least in the coronal section (p < 0.05).

Conclusion Although none of the methods cleaned the isthmus completely, nickel–titanium (NiTi) systems and ultrasonic and sonic systems removed more debris than the side-perforated needle syringe irrigation.
Characterization of persistent headache attributed to past stroke
Authors: Rêgo André , Pinheiro Rita , Delgado Sofia , Bernardo Francisco , Parreira Elsa
Published: November 2022

Background Persistent headache attributed to past stroke (PHAPS) is a controversial entity, recently included in the third edition of the International Classification of Headache Disorders (ICHD-3) despite being described only in retrospective studies.

Objective To determine the frequency and characteristics of PHAPS in patients admitted with acute stroke.

Methods We selected all patients with headache associated with acute stroke (HAAS) from a prospective, single-center registry of patients with acute stroke admitted to a Neurology ward between November 2018 and December 2019. We analyzed demographic, clinical, and neuroimaging data. We assessed the follow-up with a phone call questionnaire at 6 to 12 months.

Results Among 121 patients with acute stroke, only 29 (24.0%) had HAAS. From these, 6 (5.0%) were lost to follow-up. In total, 23 (20.0%) patients answered the 6- to 12-month follow-up questionnaire and were included in this study. The median age of the sample was 53 years (interquartile range [IQR]: 38–78 years), and there was no sex predominance. Of the 10 patients (8,3%) that had persistent headache, 8 (6.6%) suffered from previous chronic headaches; however, they all mentioned a different kind of headache, and 1 (0,8%) probably had headache secondary to medication.

Conclusions In the present study, only 10 out of 121 stroke patients (8.3%) referred persistent headache at the 6- to 12-month follow-up, but the majority already suffered from previous chronic headache, which raises the question that the actual prevalence of PHAPS may be lower than previously reported.
Evaluation of electrocardiographic P wave parameters in predicting long-term atrial fibrillation in patients with acute ischemic stroke
Authors: Çinar Tufan , Hayiroğlu Mert İlker , Selçuk Murat , Cinier Göksel , Çiçek Vedat , Doğan Selami , Kiliç Şahhan , Asal Süha , Atmaca Murat Mert , Orhan Ahmet Lütfullah
Published: November 2022

Background Electrocardiographic parameters, such as P wave peak time (PWPT), P wave duration (PWD), and P wave amplitude in lead DI, have been utilized to assess left atrial anomalies linked to the development of atrial fibrillation (AF) in different cohort settings.

Objective To compare electrocardiographic parameters, such as P waves, in predicting long-term AF risk in acute ischemic stroke cases.

Methods The data of 231 consecutive acute ischemic stroke cases were retrospectively collected. Two independent cardiologists interpreted the electrocardiography recordings for PWPT, PWD, and P wave amplitude in lead DI. The median follow-up study period was 16 (interquartile range [IQR]: 11–24) months.

Results In total, AF was detected in 43 (18.6%) cases. All studied P wave parameters were found to be statistically significant in cases with AF. Based on multivariable logistic regression analysis, dementia, left atrium volume index, PWD (razão de chances [RC]: 1.11; 95% confidence interval [CI]: 1.058–1.184; p = 0.003), PWPT in lead DII (RC: 1.030; 95%CI: 1.010–1.050; p = 0.003), and advanced interatrial block morphology were independent predictors of long-term AF. P wave duration had the highest area under the curve value, sensitivity, and specificity for long-term AF in such cases compared with the other P wave parameters.

Conclusions Our head-to-head comparison of well-known P wave parameters demonstrated that PWD might be the most useful P wave parameter for long-term AF in acute ischemic stroke cases.
Early Radiographic Outcomes of Vascularized Pedicle Bone Grafting in Foot: A Case Series
Authors: Coxe Francesca R. , Bogner Eric A. , Cooke Margaret E. , O'Malley Martin J. , Ellis Scott J. , Fufa Duretti T.
Published: November 2022

Background Navicular nonunion and talar avascular necrosis may result from limited blood supply predisposing to injury and impaired healing. Vascularized pedicled bone grafting is a promising adjunct to treat these challenging conditions, offering the susceptible diseased site structural and vascular support. We report the early radiographic and clinical outcomes of vascularized pedicled bone grafting in patients with navicular nonunion, talonavicular fusion nonunion, and talar avascular necrosis.

Methods Patients with navicular nonunion, talonavicular fusion nonunion, or talar avascular necrosis who underwent vascularized pedicled bone grafting at our institution from January 2014 to February 2019 were retrospectively identified. Radiographic evidence of healing was monitored postoperatively as defined by: progression toward union on CT for nonunion and absence of disease progression on MRI or CT for avascular necrosis. Surgical complications and need for additional surgeries were documented.

Results Eight patients were included who underwent vascularized pedicled bone grafting for navicular nonunion (N = 5), talonavicular fusion nonunion (N = 1), and talar avascular necrosis (N = 2). Average clinical follow-up was 10.8 months (range 4–37). All patients had 4 or more months postoperative radiographic follow-up with MRI or CT. Seven of eight patients demonstrated evidence of radiographic healing. One patient required additional surgery due to external fixator pin site infection. No other complications were reported.

Conclusion Our results corroborate prior case series suggesting vascularized pedicled bone grafting is a safe and reliable procedure for treating navicular nonunion, talonavicular fusion nonunion, or talar avascular necrosis with potential to spare or delay need for salvage procedures in the younger patient population.

Level of Evidence The evidence level is Level V.
Does Surgeon Level of Expertise Correlate with Patient Outcomes?
Authors: Geller Joseph S. , Cohen Lara L. , Massel Dustin H. , Donato Zachary J. , Chen David , Dodds Seth D.
Published: November 2022

Background It is difficult to evaluate the results of surgical techniques as there is inherent variability between surgeons in regard to experience, skill level, and knowledge. Tang suggested a classification system in 2009 in an attempt to standardize surgeon level of expertise, with categories ranging from nonspecialist (Level I) to expert (Level V). This epidemiological analysis of all articles citing Tang's original paper examines if a surgeon's self-reported level of expertise correlates with outcomes and evaluates whether the current definition of Tang level is sufficient to account for expertise bias.

Methods In May 2021, all articles citing Tang level of expertise were identified (N = 222). Articles were included if they described a novel technique and provided author(s)' levels (n = 205). Statistical analysis was conducted, and p-values less than 0.05 were considered significant.

Results The most common specialties reporting Tang level of expertise were orthopaedic surgery (82.9%) and plastic surgery (15.5%). The most common subspecialty was hand surgery. 2020 was the year with the most studies reporting level of expertise (31.7%), followed by 2021 (20.0%) and 2019 (17.1%). The majority of studies (80.5%) reported positive results with their technique, and of these, 63.3% were statistically significant. Level of expertise was not significantly associated with a doctoral degree, type of residency completed, fellowship completion, hand fellowship, author sex, study type, or result significance.

Discussion The current Tang classification is both underreported and incomplete in its present state. To account for expertise bias, we recommend all authors report Tang level when describing surgical techniques. Studies with multiple authors should explicitly state the level of each author, as well as a weighted average accounting for the total contribution of each individual.
Long-term Outcomes following Operative Management of Pediatric Scapholunate Ligament Injuries
Authors: van Kampen Robert J. , Fox Paige M. , Baltzer Heather L. , Moran Steven L.
Published: November 2022

Background Scapholunate (SL) ligament injuries are rarely diagnosed in children. This study reports the outcomes of surgically treated SL ligament injuries in patients younger than 18 years.

Methods A retrospective review was performed on 20 pediatric patients with SL ligament injuries. Records were reviewed for preoperative and postoperative radiographic data, intraoperative findings, classifications of interosseous ligament injury, and postoperative course.

Results Thirteen girls and seven boys sustained SL injuries requiring operative intervention and were followed for an average of 26 months. Magnetic resonance imaging (MRI) was performed in 15 patients, which revealed an SL tear in 7 patients. Arthroscopically, SL injuries were classified as Geissler grade III in 12 patients and grade IV in 5 patients. Based on the Mayo Wrist Score, nine patients had excellent or good results, while six demonstrated fair results. The mean wrist flexion–extension arc was 109 degrees, while the mean grip strength was 82% of the unaffected side. Patients treated >1 year following injury had significantly decreased grip strength and Mayo Wrist Score.

Conclusion In this study, worse results were seen in children with a protracted course prior to treatment of an SL injury. A high index of suspicion is necessary to detect an SL injury in the younger age group and should be in the differential for those with persistent dorsal wrist pain, tenderness over the dorsal SL joint, and/or positive Watson's test. MRI may assist in diagnosis but is not definitive to rule out injury. Arthroscopy is valuable to determine the extent of injury.
Van der waals equation of state
Authors: Gorenstein Mark
Published: November 2022

Van der Waals (vdW) invented his equation of state about 150 year ago. This equation described the liquidgas phase transition and predicted an existence of the critical point. The vdW equation of state remains today the most familiar and one of the most successful model in molecular physics. It is presented in all text books on statistical physics. However, several important questions concerning the vdW model had no answers. Only very recently these questions were discussed in the literature, and several important extensions of the vdW equation of state were developed. These new results presented in this article correspond to the grand canonical ensemble formulation, the effects of quantum statistics, and applications of the vdW model to nuclear matter taking into account Fermi statistics for interacting protons and neutrons. A special attention is also paid to the particle number fluctuations in a vicinity of the vdW critical point.
Geometrical presentation of elementary particle wave function
Authors: Lev Bohdan
Published: November 2022

This article presents a short review of a geometric approach to the theory of elementary particles which was proposed early. The wave function of particle, instead of the spinor representation, is given by the Clifford number, whose transfer rules have the structure of the Dirac equation for any manifold. The solution to this equation is obtained in terms of geometric characteristics. New experiments are proposed to show the geometric nature of the wave function of an elementary particle.
Finite element analysis of pitting pit on residual strength of magnesium alloy welded joint
Authors: Gong Xiaoyuan , Liu Jinming , Li Junqi , Xiao Fengqing
Published: November 2022

This work analyzes the Tungsten Inert Gas (TIG)welded joint of AZ31 magnesium alloy and the pitting corrosion stress field at different depths under tensile load via the ANSYS finite element method. The strengths of the stress and strain fields inside the corrosion pit were substantially higher than the average strength level of the matrix. Therefore, under the influence of the applied load, the corrosion pit will fail first. Based on the study of pitting corrosion, a model was developed to explain how pitting corrosion cracks propagate in magnesium alloy welded joints. Finally, the variation of residual strength was revealed to study the corrosion dynamic mechanism of the joints.
FPGA: Field programmable gate array-based four-channel embedded system for ultrasonic imaging of under-water concrete structures
Authors: Jain Harshit , Patankar V. H.
Published: November 2022

Non-destructive testing is needed for the evaluation of quality and safety of concrete structures in the field of civil engineering. The imaging of concrete/reinforced cement concrete structures (RCC) is a challenging task due to the non-homogeneous properties of the concrete material. To address this challenge, a novel real-time, re-configurable, four-channel embedded system has been designed and developed to image the internal details of the concrete samples using the water immersion pulse-echo (PE) mode under automation, which needs access from one side of the structure. The system performs data acquisition (DAQ) of the amplified echo signals under the control of the computer via a universal serial bus interface. A graphical user interface (GUI) has been developed using C# in a Visual environment, for image acquisition and control of the DAQ parameters. The performance of the system has been evaluated by acquiring B-Scan images of three types of concrete test blocks having side drilled holes (SDHs) and simulated inclusions embedded in concrete blocks of M20 grade using a linear array of 92 kHz water immersion transducers operating in under-water PE mode. The acquired B-Scan images revealed the internal details of the concrete test blocks with sizing of the SDHs and inclusions. Therefore, the developed four-channel ultrasonic imaging system can visualize the internal details of under-water concrete structures, such as bridges and sea links, with the help of corresponding 2-D cross-sectional images, acquired using the developed system.
Design of a Multi-Monochromatic X-ray Imager (MMI) for Kr K-shell line emission
Authors: Gallardo-Diaz E. , Mancini R. C. , Cliche D. T. , Tommasini R.
Published: November 2022

The Multi-Monochromatic X-ray Imager (MMI) is a time-gated spectrometer used in implosion experiments at the OMEGA laser facility. From the data, electron temperature and density spatial distributions can be obtained at different implosion times. Previous MMI designs used Ar K-shell emission (3–6 keV) as a spectroscopic tracer and provided a spectral resolution of around 20 eV. However, Ar K-shell line emission becomes less useful at electron temperatures above 2 keV due to over-ionization. Kr K-shell (12–16 keV) has been shown to be an attractive alternative to diagnose hot implosion cores in recent publications. The purpose of this paper is to show a new point design that allows the MMI to detect this higher photon energy range with suitable spectral resolution. The algorithm used to find the optimal design couples a ray-tracing code and an exhaustive parameter space search. This algorithm may be useful as a tool to find optimal MMI designs for other purposes, i.e., other spectral regions for other spectroscopic tracers. The main change between the two designs is the replacement of the multi-layer mirror with a flat Bragg Ge (220) crystal. The final Kr K-shell MMI design has a photon energy range from 12 to 16.1 keV.
The three-dimensional generalized Hénon map: Bifurcations and attractors
Authors: Hampton Amanda E. , Meiss James D.
Published: November 2022

We study dynamics of a generic quadratic diffeomorphism, a 3D generalization of the planar Hénon map. Focusing on the dissipative, orientation preserving case, we give a comprehensive parameter study of codimension-one and two bifurcations. Periodic orbits, born at resonant, Neimark–Sacker bifurcations, give rise to Arnold tongues in parameter space. Aperiodic attractors include invariant circles and chaotic orbits; these are distinguished by rotation number and Lyapunov exponents. Chaotic orbits include Hénon-like and Lorenz-like attractors, which can arise from period-doubling cascades, and those born from the destruction of invariant circles. The latter lie on paraboloids near the local unstable manifold of a fixed point.
Molecular dynamics study of the growth of ZnOx films
Authors: Hantova Kamila , Houska Jiri
Published: November 2022

Crystalline zinc oxide thin films are important due to a combination of optical transparency, electrical conductivity, and piezoelectric and pyroelectric properties. These functional properties are improved with increasing perfection of the crystalline structure. In this paper, classical molecular dynamics with a reactive force field was used to simulate the atom-by-atom growth of ZnOx films on a crystalline template. Contrary to previous modeling studies, the effect of a wide range of process parameters (elemental ratio x, kinetic energy of arriving atoms, and fraction of fast atoms in the particle flux) on the film crystallinity was investigated. All the parameters were found to have a significant impact. Counterintuitively, the highest crystal quality was obtained for slightly overstoichiometric films with x > 1. The results provide a quantitative insight into the role of individual deposition parameters, and the identification of their optimum values facilitates a further improvement of the film properties.
Rotational dynamics of water associated with interfacial dielectric oscillation and its role in crystal growth of ice
Authors: Guo Chenchen , Qin Hairong , Zhu Yong , Chen Min , Lü Yongjun
Published: November 2022

The rotational dynamics of water near the ice/water interface and its relation with the crystal growth of ice are investigated by using molecular dynamics simulations. We find that the dipole-moment profiles of water adjacent to interfaces display an oscillation behavior, which is in contrast to the monotonic decay near the free surface for water films. This dielectric oscillation phenomenon is associated with the strong response to hard solid/water interface. It significantly suppresses the dielectric relaxation and slows down the rotational diffusion near the interface compared to bulk water. We propose that the rotational diffusion determines the active degree of growth sites on interfaces, and its slowdown due to the interfacial dielectric oscillation contributes to reducing the growth rate of ice. With this idea, we predict the crystal growth rate of ice based on the modified Wilson–Frenkel model involving rotational dynamics. The theoretical result agrees well with the simulation.
Simultaneous measurements of axial motion and azimuthal rotation of non-uniformities (“spokes”) in a Hall thruster
Authors: Guglielmi A. , Gaboriau F. , Boeuf J. P.
Published: November 2022

Low-frequency instabilities are often present in Hall thrusters and are associated with axial and/or azimuthal oscillations of plasma non-uniformities. The axial oscillations are related to the so-called breathing mode (periodic depletion of the neutral atom density due to ionization) and are associated with large amplitude current oscillations. The low-frequency azimuthal instabilities are characterized by local non-uniformities of the light emission rotating in the azimuthal direction and are generally called “rotating spokes.” The possibility of coexistence of these two modes has been discussed in the literature but without clear experimental evidence of their correlation. In this paper, we present for the first time simultaneous measurements of the axial and azimuthal positions of the spoke. These measurements have been obtained with a high-speed camera using a triangulation method based on parallax. This method has proven to be sufficiently sensitive to track the 3D position (r–θ–z) of local non-uniformities of the light emission. The optical method has been synchronized with measurements of the current on a segmented anode. The results show that under some conditions, breathing oscillations and spoke rotation in the E×B direction are coupled. During the current rise, the spoke moves from the anode region toward the channel exhaust region while rotating in the E×B direction and seems to follow the movement of the front of neutral atoms progressively filling the channel. About 60% ± 20% of the total anode current is carried by the spoke.
Bimolecular reactivity of 3d metal-centered excited states (Cr, Mn, Fe, Co)
Authors: Förster Christoph , Heinze Katja
Published: November 2022

Metal-centered (MC) excited states (ESs) of 3d transition metal complexes (TMCs) often possess rather low energies so that these represent the lowest energy ESs. Additionally, MC states are often strongly distorted, hence they efficiently decay non-radiatively to the ground state. As bimolecular photoinduced electron transfer (PET) and energy transfer (EnT) processes require contact to the substrate, the metal confinement of the ES wavefunction of MC states makes these processes challenging. Consequently, MC states are considered less useful as compared to long-lived charge transfer states of higher energy with wavefunctions extending onto the ligands. Despite these supposed drawbacks, some classes of TMCs can successfully engage in bimolecular PET and EnT processes with MC states being the photoactive states. We discuss these initial examples of MC ES reactivity covering chromium, manganese, iron, and cobalt complexes with the aim to gain a deeper understanding of these processes and to identify the decisive key parameters. Finally, we present catalytic photoredox and energy transfer processes using photosensitizers with suitable MC ESs.
Scaling of reconnection parameters in magnetic island coalescence: Role of in-plane shear flow
Authors: Mahapatra Jagannath , Ganesh Rajaraman , Sen Abhijit
Published: November 2022

A 2D incompressible viscoresistive-MHD model [Mahapatra et al., Phys. Plasmas 28, 072103 (2021)] is used to study the scaling of reconnection parameters in the magnetic island coalescence problem under two interesting scenarios. First, the effect of changing island half-width at a fixed system size is investigated. As the island half-width increases, the total magnetic flux content of the islands increases, resulting in an increase in upstream magnetic field, upstream velocity field, and unnormalized reconnection rate. However, the downstream magnetic field, current sheet length and normalized reconnection rate (normalized to the upstream magnetic field and upstream Alfvénic velocity) remain independent of it. Interestingly, the reconnection rate is found to be different from the upstream to downstream velocity ratio as well as from the aspect ratio of the current sheet, as opposed to the findings of the Sweet–Parker model. Second, the in-plane shear flow effects are studied, keeping the island width and system size fixed. Here, thickness and length of the current sheet, the upstream magnetic and velocity field components, reconnection rate and time, current sheet inclination angle with shear flow length scale, and amplitude are calculated. Interestingly, the inclination angle of the current sheet and the diffusion region are found to be different, and the differences are more in stronger shear flows. These results are significantly different from the Harris sheet setup with shear flow.
Turbulence structure under the free-surface wave around an advancing surface-piercing cylindrical body
Authors: Park Jongyeol , Seo Jeonghwa , Lee Sang Bong , Rhee Shin Hyung
Published: November 2022

Free-surface wave effects on the turbulent boundary layer and wake of a surface-piercing slender body are investigated by measuring the flow and free-surface elevation around the model in three different Froude number (Fr) conditions—0.126, 0.282, and 0.400. The flow is measured by a towed underwater stereoscopic particle image velocimetry system. At the lowest Fr of 0.126, there appears no significant wave pattern, but the flow retards under the free-surface. The free-surface hinders the flow underneath, as the solid surface does. The steady and smooth free-surface wave generated at the intermediate Fr of 0.282 affects the pressure gradient on the turbulent boundary layer. The momentum thickness increases due to the adverse pressure gradient from the wave trough to the wave crest. At the highest Fr of 0.400, a strong adverse pressure gradient results in flow separation and violent wave breaking. The wave-induced separation at the high Froude number condition stimulates momentum transfer and turbulence dissipation, resulting in isotropic turbulence.
A versatile chemical vapor synthesis reactor for in situ x-ray scattering and spectroscopy
Authors: Schroer Martin A. , Levish Alexander , Yildizlar Yasin , Stepponat Maximilian , Winterer Markus
Published: November 2022

We describe a versatile reactor system for chemical vapor synthesis of nanoparticles, which enables in situ investigations of high temperature gas phase particle formation and transformation processes by x-ray scattering and x-ray absorption spectroscopy. The system employs an inductively heated hot wall reactor as the energy source to start nanoparticle formation from a mixture of precursor vapor and oxygen. By use of a modular set of susceptor segments, it is especially possible to change solely the residence time of the gas mixture while keeping all other process parameters (temperature, gas flow, pressure) constant. Corresponding time–temperature profiles are supported by computational fluid dynamics simulations. The operation of the system is demonstrated for two example studies: tin oxide nanoparticle formation studied by small angle x-ray scattering and iron oxide nanoparticle formation by x-ray absorption spectroscopy.
Lagrangian analysis of the flow induced by a dielectric barrier discharge plasma actuator array under burst mode actuation
Authors: Wang Yu-Shuai , Wu Bin , Gao Chao , Yuan Xian-Shi , Zhang Yi-Xing , Wang Na , Xu Ze-Yang , Li Yue-Qiang , Wang Yu-Ling , Hao Dong-Dong
Published: November 2022

The dynamic properties of the flow induced by a dielectric barrier discharge (DBD) plasma actuator array are investigated from the Lagrangian perspective. First, numerical simulations based on a body force model are performed to obtain the flow field induced by unsteady plasma actuation in the burst mode. The numerical simulations capture the flow characteristics of plasma actuation well. Subsequently, the ridges of the finite-time Lyapunov exponent field are employed to identify the Lagrangian coherent structures (LCSs). Both the attracting and repelling LCSs organize the plasma-induced flow’s dynamic behaviors. The attracting LCSs visualize the plasma-induced vortices. The vortex formation, development, and merging processes in the unsteady plasma actuation are resolved well by the LCSs. The material transport in the plasma-induced flow is analyzed by tracing the fluid particle motions. Then, the influences of the actuation parameters, duty cycle, and burst frequency on the flow structures are explored via the attracting LCSs. The presented results enhance the understanding of plasma actuation flow physics and promote the optimal use of DBD plasma actuator arrays.
Reduction of noise induced by power supply lines using phase-locked loop
Authors: Abe M. , Yamashita H. , Jinno S. , Custance O. , Toki H.
Published: November 2022

An experimental implementation for the reduction of power-line noise in delicate signal detection is presented. This implementation improves the signal-to-noise ratio without limiting the bandwidth of the measurement. A sinusoidal wave and its harmonics, both synchronized with the frequency of the power line, are used to cancel out the power supply noise induced in the measurement signal. The wave and the harmonics are generated via a phase-locked loop implementation. Their amplitude and phase are adjusted, and then they are added to the measurement signal using a series of operational amplifiers to compensate for the noise. Although we applied this method to the particular case of scanning tunneling microscopy measurements, considerably improving the image quality, our implementation can be applied to other measurement systems for which noise from the power lines can compromise the signal detection.
Measures of the yield stress fluids oriented for dysphagia management using steady-state shear, transient shear, and large-amplitude oscillatory shear (LAOS)
Authors: Wei Yuanyuan , Li Ruiqi , Zhang Hongbin
Published: November 2022

Dysphagia has become a highly prevalent and ever-growing disease among the elderly in today's society. Polysaccharide-thickened food with yielding features oriented toward dysphagia management has been recognized as a suitable diet capable of alleviating the swallowing risk by allowing the swallow-related muscles to coordinate this activity with appropriate timing. However, the divergence of different measures and the resultant discrepancy between yield stress values remains that experimentally and theoretically impedes the understanding of yielding features of food on the efficiency of dysphagia management. Herein, we compared the typical rheological approaches to yielding measurement, including steady-state shear, transient shear rate ramp, and large-amplitude oscillatory shear (LAOS), based on three polysaccharide-thickened solutions and nutrition emulsions. As a hallmark of thixotropy properties, the hysteresis loop was quantitatively illustrated for the three polysaccharide emulsions to distinguish them as simple or complex yield stress fluids. The Herschel–Bulkley model was employed to obtain the dynamic yield stress in steady-state shear mode. Yield stress estimated by transient shear and small oscillatory shear methods is comparable. Importantly, different from the common approaches that acquire only one critical yield stress value, the stress bifurcation method from LAOS employed in this work enabled us to estimate the yielding onset and end in the solid–liquid transition process of the fluids, which may bring new insight and motivate innovative idea in the diet design in dysphagia management.
Change point detection in multi-agent systems based on higher-order features
Authors: Gu Kongjing , Yan Liang , Li Xiang , Duan Xiaojun , Liang Jingjie
Published: November 2022

Change point detection (CPD) for multi-agent systems helps one to evaluate the state and better control the system. Multivariate CPD methods solve the d×T time series well; however, the multi-agent systems often produce the N×d×T dimensional data, where d is the dimension of multivariate observations, T is the total observation time, and N is the number of agents. In this paper, we propose two valid approaches based on higher-order features, namely, the Betti number feature extraction and the Persistence feature extraction, to compress the d-dimensional features into one dimension so that general CPD methods can be applied to higher-dimensional data. First, a topological structure based on the Vietoris–Rips complex is constructed on each time-slice snapshot. Then, the Betti number and persistence of the topological structures are obtained to separately constitute two feature matrices for change point estimates. Higher-order features primarily describe the data distribution on each snapshot and are, therefore, independent of the node correspondence cross snapshots, which gives our methods unique advantages in processing missing data. Experiments in multi-agent systems demonstrate the significant performance of our methods. We believe that our methods not only provide a new tool for dimensionality reduction and missing data in multi-agent systems but also have the potential to be applied to a wider range of fields, such as complex networks.
Acoustic reflected wavefront modulation based on Helmholtz resonator array
Authors: Wang Rui , Yang Fengbao
Published: November 2022

In this work, a Helmholtz resonator (HR) with a subwavelength scale is proposed to modulate the acoustic wavefront in multiple manners. The phase response of the reflection wave can be continuously adjusted by altering the height of the cavity. Several HR arrays with gradient phase shifts are constructed to achieve various beam shaping phenomena, including beam deflection and beam focusing. Both the reflection angle and the focal length can be controlled by changing the phase gradients along the structure. Meanwhile, the binary design with only two kinds of HR is utilized to achieve multifunctional acoustic wavefront modulations, which extremely simplify the design philosophy. Moreover, by taking advantage of the resonance mechanism of the HR, an integrated structure composed of two HRs with different cavity volumes is adopted to achieve bifunctional acoustic wavefront modulations, making it convenient to customize the switchable device on demand. Our work offers a solution for multifunctional reflected acoustic wavefront modulations, which may have potential applications in acoustic communication, detection, and holography.
Development of gas signatures of smouldering peat wildfire from emission factors
Authors: Hu Yuqi , Rein Guillermo
Published: November 2022

Smouldering peat fires are responsible for regional haze episodes and cause environmental, social and health crises. Owing to the unique burning characteristics of smouldering peat, identifying and detecting this kind of fire remains a challenge. This work explores smouldering peat gas signatures using emission factor (EF) data from literature. Systematic comparisons and statistical analyses were carried out to investigate 28 forms of EF combinations created from the four most abundant gas species: carbon dioxide (CO2), methane (CH4), carbon monoxide (CO) and ammonia, from smouldering peat, flaming savanna and grassland, agricultural residue and forest fires. Among the candidate gas signatures, the ratio of EF(CO2) to EF(CH4) for smouldering peat showed a significant improvement with statistically different ranges of values (134.6) compared to those from flaming savanna and grassland fire (940.2), agricultural residue fire (434.4 ), forest fire (368.8) and mixed burning peat fires (207.7). Additionally, we found that EF(CO2)/EF(CH4) is independent from fuel composition and could differentiate early ignition from the subsequent spread, making it the best gas signature among those analysed, including CO/CO2 ratio and the Modified Combustion Efficiency. This work presents the first scientific endeavour developing smouldering gas signatures, contributing to the scientific understanding and remote sensing and early detection of smouldering peat wildfires.
Recovering information in an asymptotically flat spacetime in quantum gravity
Authors: Chowdhury Chandramouli , Papadoulaki Olga
Published: November 2022

As an extension of Chowdhury et al (2021 SciPost Phys.
10 106) and Laddha et al (2021 SciPost Phys.
10 041) we present a physical protocol that a set of observers can use to detect a pure state in the bulk when they are spread across a small cut near

in flat spacetime. The protocol involves the modification of a bulk state using simple unitary operators and measurements of the energy of the state. The states that we study are constructed by acting with low energy operators on a vacuum state such that a perturbative analysis is valid. We restrict ourselves to

3
+
1

dimensional spacetimes and only consider massless excitations. From this analysis, the principle of holography of information becomes manifest in the case of asymptotically flat spacetime.
Resonant jumps induced by stationary tidal perturbation: a two-for-one deal
Authors: Gupta Priti , Kakehi Takafumi , Tanaka Takahiro
Published: November 2022

Extreme-mass-ratio inspirals (EMRIs) are promising target sources for space-based interferometers such as LISA, Taiji, and Tianqin. Depending on the astrophysical environment, such as close perturbers or an accretion disk, EMRI orbital evolution may deviate from the predictions of general relativity in vacuum. In particular, we focus on the resonance jumps, i.e. the changes of the conserved quantities induced by a stationary perturbation to the background Kerr geometry. Using Hamiltonian formulation, we provide a closed relation between the jump in Carter constant and that in the axial component of angular momentum. It is also shown that the obtained relation is consistent with the fitting formulae computed for the tidal resonance in previous works.
Neutron phase contrast imaging of PbWO4 crystals for G experiment test masses using a Talbot-Lau neutron interferometer
Authors: Assumin-Gyimah K T A , Dutta D , Hussey D S , Snow W M , Langlois C , Lee V
Published: November 2022

The use of transparent test/source masses can benefit future measurements of Newton’s gravitational constant G. Such transparent test mass materials can enable nondestructive, quantitative internal density gradient measurements using optical interferometry and allow in-situ optical metrology methods to be realized for the critical distance measurements often needed in a G apparatus. To confirm the sensitivity of such optical interferometry measurements to internal density gradients it is desirable to conduct a check with a totally independent technique. We present an upper bound on possible internal density gradients in lead tungstate (PbWO4) crystals using a Talbot-Lau neutron interferometer on the Cold Neutron Imaging Facility at NIST. We placed an upper bound on a fractional atomic density gradient in two PbWO4 test crystals of

1
N

d
N

d
x

<
0.5
×

10

−
6

 cm−1. This value is about two orders of magnitude smaller than required for G measurements. We discuss the implications of this result and of other nondestructive methods for characterization of internal density inhomogeneties which can be applied to test masses in G experiments.
Exploring the subtle factors that control the structural preferences in Cu7Te4
Authors: Koch Peter , Steinberg Simon
Published: November 2022

In the quest for materials suited as components in future technologies, the copper-rich regions of the binary Cu–Te system have been of great interest. In this context, several explorative efforts were also focused on Cu7Te4 which was reported to crystallize with different types of structure. To explore the structural preferences for two Cu7Te4 structure models, both experimental as well as quantum-chemical means were employed. The crystal structures of both Cu7Te4 types are composed of hexagonal closest packed layers of tellurium atoms, and differ in the respective distributions of the copper atoms between these layers. The analysis of the electronic structures was accomplished based on the densities-of-states, Mulliken charges, projected crystal orbital Hamilton populations, and electron localization functions of both structure models, and its outcome indicates that the factors that control the formation of a respective type of structure are rather subtle.
Cross-domain fault diagnosis of rotating machinery based on graph feature extraction
Authors: Wang Pei , Liu Jie , Zhou Jianzhong , Duan Ran , Jiang Wei
Published: November 2022

Transfer learning can realize cross-domain fault diagnosis of rotating machinery, where the model trained on many labeled samples collected in one working condition can be transferred to insufficient samples collected in the target working condition. Currently, the data features cannot be completely extracted by existing methods when the data distribution gap of the samples collected in different working conditions is quite large. In order to fully extract the data features of rotating machinery to achieve cross-domain fault diagnosis, this paper investigated a cross-domain fault diagnosis model of rotating machinery based on graph feature extraction. The proposed method can realize unsupervised fault diagnosis on rotating machinery running under different working conditions by extracting the numerical and structural features of source and target domains. First of all, data features with large data distribution gaps need to be fully extracted, so a convolutional network based on a deformable convolutional network (De-conv) is designed to extract the features with large differences in data distribution under various working conditions. Secondly, features are extracted based on a convolutional neural network for data values in existing domain adaptation (DA) methods while the structure features of machine monitoring data are ignored. Therefore, a composite spectral-based graph convolutional network is designed to extract structural features of data. Thirdly, fully extracted features are input into a universal DA network to achieve cross-domain fault diagnosis of unknown faults in rotating machinery under changing working conditions. Finally, a benchmarking data set and a data set collected from a practical experimental platform are used to verify the effectiveness of the proposed model, and the results show that it is more suitable for cross-domain fault diagnosis of rotating machinery than other comparison models.