bluuebunny/crossref_metadata_2025 huggingface dataset:
Planet-induced spirals in the circumbinary disk of GG Tauri A
Authors: Phuong N. T. , Dutrey A. , Di Folco E. , Guilloteau S. , Pierens A. , Bary J. , Beck T. L. , Chapillon E. , Denis-Alpizar O. , Diep P. N. , Majumdar L. , Piétu V. , Tang Y.-W.
Published: March 2020

Context. ALMA high angular resolution observations of the dust and CO emission have already revealed signatures of protoplanets embedded in protoplanetary disks. These detections are around single T Tauri stars, while exoplanet surveys reveal that planets can also form in binary (or multiple) systems, either in circumstellar or circumbinary orbits.

Aims. We searched for indirect evidence for planet formation in the multiple system GG Tau A, which harbors the most massive circumbinary disk among T Tauri stars.

Methods. We performed CO(2–1) ALMA Cycle 6 observations of GG Tau A at 0.3″ resolution. The images confirm the “hot spot” detected at higher frequencies, but also reveal prominent spiral-like features. We modeled these features using the analytic prescription for the linear perturbation regime induced by low-mass planets.

Results. The brightest spiral is well reproduced by a density wave excited by a protoplanet (GG Tau Ac) at the hot-spot location (290 au), just outside the dust ring. The absence of a clear gap (in gas or dust) at the planet location implies that its mass is significantly lower than that of Jupiter, i.e., of about the mass of Neptune or lower. Furthermore, other prominent (trailing) spiral patterns can be represented by adding one (or more) planet(s) at larger orbital radii, with the most obvious candidate located near the 2:1 mean-motion resonance with GG Tau Ac.

Conclusions. The (proto-)planet GG Tau Ac appears to externally confine the ring in a stable configuration, explaining its high mass. Our results also suggest that planets similar in mass to Neptune may form in dense circumbinary disks orbiting (wide) binary stars. In the GG Tau case, orbital resonances appear to play an important role in shaping this multiple circumbinary planet system.
Analysis of a hybridizable discontinuous Galerkin scheme for the tangential control of the Stokes system
Authors: Gong Wei , Hu Weiwei , Mateos Mariano , Singler John R. , Zhang Yangwen
Published: March 2020

We consider an unconstrained tangential Dirichlet boundary control problem for the Stokes equations with anL2penalty on the boundary control. The contribution of this paper is twofold. First, we obtain well-posedness and regularity results for the tangential Dirichlet control problem on a convex polygonal domain. The analysis contains new features not found in similar Dirichlet control problems for the Poisson equation; an interesting result is that the optimal control has higher local regularity on the individual edges of the domain compared to the global regularity on the entire boundary. Second, we propose and analyze a hybridizable discontinuous Galerkin (HDG) method to approximate the solution. For convex polygonal domains, our theoretical convergence rate for the control is optimal with respect to the global regularity on the entire boundary. We present numerical experiments to demonstrate the performance of the HDG method.
A computational model of interaction between material and interface cracks
Authors: Vodička Roman
Published: March 2020

A quasi-static model for numerical solution of initiation and propagation of cracks along interfaces or inside materials is developed. The two types of cracks are modelled by the material damage theory with two independent damage parameters introduced. For cracks at the interface, in fact represented by contact of construction components, cohesive or adhesive contact is considered, for which several computational relationships based on energetic formulation exist. Accordingly, the appropriate modelling of bulk damage also includes energy consideration. In terms of cracks, it leads to so called diffuse cracks. The computational approach is referred to as phase field models. These will cause damage in a very narrow band representing the actual crack. The computational analysis provides stress-strain quantities and the damage variables to simulate both interface and material cracks. The proposed mathematical approach has a variational form based on an energetic formulation looking for a kind of weak solution. The solution is approximated by a time stepping procedure, a finite element code, and it utilizes quadratic programming algorithms.
Path-independent J-integral for cracks in decagonal quasicrystals
Authors: Sladek Jan , Sladek Vladimir , Repka Miroslav
Published: March 2020

The path-independent J-integral is derived for fracture mechanics analysis of decagonal quasicrystals (QCs). The gradient theory of quasicrystals is developed here to consider large strain gradients at the crack tip vicinity. The constitutive equations contain phonon and phason stresses, and the higher-order stress tensor. The higher-order elastic material parameters are proportional to the internal length material parameter and the conventional elastic coefficients. The FEM equations are derived to solve general boundary value problems for the strain gradient theory of the QCs.
Analysis of floor response spectra of an office building
Authors: Jendzelovsky Norbert , Grmanova Alzbeta
Published: March 2020

The paper deals with the analysis of an office building located in the outskirts of Bratislava, Slovakia. The building consists of one underground floor and five above ground floors that have been roofed by a steel roof structure. The steel structure represents a subtle roofing of areas with air condition units and other technological equipment. For proper design of the steel structure with respect to the seismic loading, it is necessary to prepare floor response spectra for the top floor. A computer model of reinforced concrete structure was created using the Finite Element Method - FEM. Based on the approved recommendations for dynamic loading, seismic load of the building was defined in the form of a synthetic three-component accelerogram at free field level. The calculations of seismic response spectra were made assuming a linearly elastic behavior of the building structure without considering the elasto-plastic effects during the earthquake. The calculation of transient analysis was performed for a three-component synthetic accelerometer in ANSYS software.

Acceleration time responses in three orthogonal directions (two horizontal and one vertical) were obtained for 6 selected points of the top floor. The obtained values of acceleration were compiled by additional software in order to obtain the resulting floor spectra. Subsequently, the envelope of the floor spectra was created, which has been taken into account in the design of a steel roof structure.
Stress analysis of the membrane structure in the shape of cone
Authors: Freiherrova Nela , Krejsa Martin , Hornakova Marie
Published: March 2020

The paper is focused on the static analysis of the cone, which is one of the basic shapes used for membrane structures. These structures are specific by their ability to transmit only tensile forces. Pressure forces in the membrane construction may cause unwanted wrinkling of the used textile materials. When designing membranes, one of the variable parameters can be the height of cone and the radius of the circular profile at the top of the cone, which affects the resulting stress and internal forces. This paper aims to analyze the reliability of the cone in terms of the extreme stress and internal forces while maintaining the same ground plan.
Probability analysis of an embedded water tank
Authors: Tvrdá Katarína
Published: March 2020

The design of building structures must fulfil specific regulations, in our case, different building standards, among them Eurocodes. In addition to deterministic procedures in structural design, these standards also allow probabilistic procedures. The embedded tank loaded with soil and liquid is solved by the probability analysis using ANSYS, which contains several probabilistic methods. The reinforced concrete tank is solved by the RSM probabilistic method, which uses the well-known Monte-Carlo method in the background. Input parameters (material properties of soil and reinforced concrete, load - pressure from water, geometric data - change of both wall and tank bottom thickness) are entered into the calculation with certain aberrances allowed by standards in the construction and loading of structures. The results are also sets of probabilistic variables with a certain variance, as opposed to a deterministic calculation, where only one value results. These procedures, which use statistical methods, have been at the forefront in recent decades. At the end of the paper, some results of the analysis of embedded reinforced concrete water tank (deterministic and probabilistic procedure) in state of tank failure on the second limit state are presented.
Base functions effect in stability finite element analysis of compressed plate
Authors: Veghova Ivana , Psotny Martin
Published: March 2020

Geometric nonlinear solution of a compressed plate is presented in this paper. Basic assumptions are specified and incremental conditional equations are derived from the variational principle of minimum of total potential energy. Full Newton-Raphson procedure, in which the stiffness matrix is updated at every equilibrium iteration, has been applied for solution. The importance of modifications of base functions for solving geometric nonlinear problems is analysed. The solved example is presented, the differences are compared and explained.
Mechanical fracture characterization of alkali-activated slag mortars with standardized and natural sand
Authors: Šimonová Hana , Kucharczyková Barbara , Bílek Vlastimil , Kocáb Dalibor
Published: March 2020

This paper is focused on the development of the physical, mechanical and fracture characteristics of alkali-activated slag (AAS) mortars during ageing. The two AAS mortars were selected for the purpose of the experiment. The difference was in a type of used sand: first mortar was made using the standardized siliceous sand with the maximum nominal grain size of 2 mm and the second mortar using the natural sand with a maximum grain size of 4 mm. The results of the elastic, fracture and strength parameters determined within the time interval of 3 to 330 days of ageing are summarized in the paper. All experimental results were evaluated for the prismatic specimens with dimensions of 40 × 40 × 160 mm and were expressed by the average value and sample standard deviation calculated from three independent measurements.
Built-up CFS column with lacings and battens
Authors: Baláž Ivan , Koleková Yvonna , Moroczová Lýdia
Published: March 2020

The built-up columns are generally used in industrial buildings, either as posts for cladding when their buckling length is very long, or as columns supporting a crane girder. The built-up columns are composed usually of two parallel chords interconnected by lacings or battens. In the paper the special type of built-up column will be analysed from Llentab Company. It consists from four parallel chords with cold-formed C cross-sections which are interconnected by lacing in one plane and by battens in four perpendicular planes. Such types of columns are especially convenient for the relatively high light steel halls. Analysis of the behaviour of such column will be performed: a) on the model with smeared equivalent bending and shear stiffness’s using analytical solution, b) on the discrete model using FEM and commercial program ANSYS. The theory of the second order taking into account the initial imperfections and the shear deformations will be employed.
Fatigue and fracture mechanical properties of selected concrete for subtle precast structural elements
Authors: Seitl Stanislav , Miarka Petr , Bílek Vlastimil
Published: March 2020

Precast concrete elements used as a civil structure are usually made of a cement-based matrix and natural aggregates (such as sand, gravel, crushed stone, etc.). These structures are usually exposed not only to a static load but also to a cyclic load if they load the bearing part of a bridge (traffic etc.). The knowledge of fatigue and fracture mechanical characteristics is important in designing and modelling new structures. This paper introduces and compares fracture mechanical properties obtained from static and fatigue tests for three kinds of concrete. The focus was set on the bulk density, flexural and compressive cube strength, fracture toughness and fatigue properties (S−N − Wöhler curve). All of these tests are important for a practical application in the design of precast concrete structures. The experimental results were statistically analysed and they showed that the fatigue and mechanical fracture properties improved with improved mechanical parameters of concrete.
The effect of openings on stress distribution in glass beams – Dependence on a hole to beam’s edge distance
Authors: Lavko Martin , Kvočák Vincent , Sokol Zdeněk
Published: March 2020

The paper defines the behaviour of simply supported monolithic glass beam consisting of only one layer glass pane with discontinuities created by four holes positioned symmetrically on the beam. Similar glass panes can be found in real constructions where they act as a beam supporting glazing, roofs or decks of nowadays very popular transparent pedestrian bridges. The main aim of this paper is to provide both experimental and numerical analysis of stress distribution alongside the beam with a focus on areas where peak stresses may occur. The areas of interest are specifically speaking around openings, around supports and in the areas where the forces are introduced to the beam. As Eurocode standards for structural glass are still in the process of codifying and most of the nowadays literature only provides suggested axial distance of holes and hole to pane edge distance based on the thickness of the glass pane. This paper will provide the future designers of glass load-bearing structures with a closer look at stress distribution around the mentioned area. It was essential to do parametric study in software using FEM to investigate as much as possible axial distances of openings without a significant increment in the total cost of the experiment.
Probabilistic modelling of prestressed concrete roof girders
Authors: Novák Drahomír , Novák Lukáš , Slowik Ondřej
Published: March 2020

The paper describes several parts of complex stochastic modelling of precast prestressed concrete girders failing in shear. Experimental studies have been performed on scaled elements as well as on full-scale girders. These tests serve as basis for developing the deterministic nonlinear model and subsequent probabilistic assessment of structural resistance. The combination of nonlinear finite element method and probabilistic analysis is a strong tool for the realistic modelling of structures, but it is extremely time consuming, especially when 3D nonlinear model with many input random parameters is analysed. Therefore, sensitivity analyses have been performed and a surrogate model has been developed. Safety formats are utilized and compared with fully probabilistic approach to determine design value of ultimate capacity of girders.
Rheological properties of rammed clay from illitic clay in relation to the amount of illite
Authors: Padevět Pavel , Bittnar Petr , Mužíková Barbora
Published: March 2020

The paper deals with the rheological properties of rammed unfired clay prepared from illitic clay. Rammed earth contains filler, binder and water. The materials were compared with the amount of filler 20 and 30% of the total weight of the mixture. The amount of water and clay affects the creep and shrinkage of the produced material. Creep properties are compared at the end of the article.
The crack formation of concrete slabs embedded along two sides with minimum area of steel reinforcement
Authors: Priganc Sergej
Published: March 2020

The article deals with crack formation of concrete slabs embedded along two sides, after monitoring the shrinking of concrete slabs under laboratory conditions. The paper presents result of laboratory test focused on monitoring the crack formation of concrete slabs. The concrete slabs were reinforced asymmetrically only on one side. The slabs were loaded by four-point bending. The formation and development of cracks was monitored during loading of concrete slabs. The deflections on the concrete slab were measured and the formation of cracks and the width of the cracks were monitored. The position of the cracks on the concrete slab was checked and compared with the position of the transverse reinforcement.
Load-bearing capacity of integrity reinforcement depending on change of the mechanical parameters of the steel
Authors: Wieczorek Barbara
Published: March 2020

The paper presents the results of numerical simulations performed on a simplified model of a slab-column connection. The aim of the investigations was to determine the value of the load at which the destruction of such a connection occurs due to a rupture of bars located above the column. In respective models, the column was situated axially or eccentrically with respect to span of bars. In each case the reinforcement passing above the column consisted of two bars. The analysis included a change in size, determining the most important parameters characterizing the properties of steel. The obtained results of calculations permitted to determine the relations between the exerted load and the displacement of the column. Based on the results, the load-bearing capacity of the reinforcing bars due to mechanical parameters of the steel was determined.
Les tests génétiques en libre accès
Authors: Jautrou Henri
Published: March 2020

Le marché des auto-tests génétiques se développe depuis une vingtaine d’années, non sans soulever des débats, voire des controverses. Qu’en est-il de la régulation de ces dispositifs dits « innovants », mais dont le statut médical est ambigu ? Un premier aspect régulatoire vient du marché lui-même, puisqu’il est en cours de forte structuration. Un second aspect régulatoire relève plus classiquement du juridique. Alors que le statut des auto-tests a longtemps manqué de clarté à l’échelle européenne, un nouveau texte (un Règlement, et non une Directive) change la situation. Il encourage une régulation « par le marché », plutôt que « par la profession médicale », ce qui n’implique pas que cette dernière n’aura aucun impact (indirect) sur le marché des auto-tests.
Un nouveau paradigme dans le traitement de l’ischémie
Authors: Tauc Michel
Published: March 2020

L’ischémie est une des préoccupations majeures des cliniciens qui y sont confrontés en permanence, que ce soit aussi bien d’un point de vue chirurgical que pathologique. Les conséquences des stress ischémiques sont dramatiques et peuvent conduire à des incapacités organiques, motrices ou cognitives. Actuellement il n’existe aucune cible moléculaire identifiée dont le ciblage pourrait être bénéfique dans ce domaine. La mouche Drosophila melanogaster, utilisée comme animal modèle, a conduit à une avancée majeure en permettant l’identification d’une toute nouvelle cible pharmacologique dont l’inhibition augmente de façon importante la tolérance à l’hypoxie. Appliqué à un modèle préclinique de transplantation rénale, cette nouvelle approche améliore nettement la reprise fonctionnelle du greffon à long terme. Cette revue retrace les étapes qui ont permis de transférer chez le mammifère supérieur une cible mise en évidence chez la drosophile, ce qui montre clairement, au-delà de la recherche fondamentale, l’apport que peut apporter un organisme modèle à la clinique.
TI-RADS und andere sonografische Klassifikationssysteme für Schilddrüsenknoten
Authors: Rogasch Julian M.M. , Wetz Christoph , Brenner Winfried
Published: March 2020

Mehrere Arbeitsgruppen und Fachgesellschaften haben in den letzten Jahren Klassifikationssysteme für die sonografische Dignitätsbeurteilung von Schilddrüsenknoten vorgeschlagen, häufig unter dem Überbegriff „TI-RADS“. Diese Systeme zielen auf eine vereinheitlichte und möglichst umfassende Beurteilung von Knoten anhand definierter sonographischer Kriterien ab. Für verschiedene Befundkonstellationen leitet sich so eine jeweilige Malignomwahrscheinlichkeit ab, und die Rate an unnötigen Feinnadelpunktionen kann nachweislich reduziert werden. Es soll zudem verhindert werden, dass wichtige Einzelaspekte der Malignitätsabschätzung im Befund nicht adressiert werden. Der Beitrag stellt eine Übersicht der relevanten Klassifikationssysteme dar, erläutert die Definitionen der einzelnen sonographischen Kriterien unterstützt durch Bildbeispiele und fasst die aktuelle Evidenz zu den genannten Systemen zusammen.
An analysis of patient’s and disease related factors predictive of the outcomes of surgery for carpal tunnel syndrome
Authors: Zyluk Andrzej , Zyluk-Gadowska Paulina , Kolodziej Lukasz , Szlosser Zbigniew
Published: March 2020

Purpose Outcomes of surgery for carpal tunnel syndrome may differ in relation to certain factors like age, duration of symptoms, clinical and electrophysiological severity. The objective of this study was an investigation into the hypothesis that several factors are predictive of results of surgical treatment of the condition.

Methods The pre- and postoperative records of 1,117 patients: 909 women (81 %) and 208 men (19 %) with a mean age of 63 years were analysed. Outcomes recorded in the sensory and functional severity scores of the Levine questionnaire were dichotomized into achieving or not-achieving a minimally clinically important difference. The effect of selected variables: sex, age, duration of symptoms, clinical and electrophysiological severity of and presence of comorbidities on outcomes of surgery at 6 months was investigated.

Results Univariate and multivariate analysis of covariates based on sex, age, duration of the disease and its clinical severity showed female gender and worse baseline symptom severity scores to be significant predictors for an improvement following carpal tunnel syndrome surgery. It showed also younger age, shorter duration of symptoms and higher baseline symptom severity scores to be predictive of a greater improvement of total grip strength, and younger age to be predictive of a greater pain cessation following surgery.

Conclusion Of all considered patient’s and disease related factors, the baseline clinical severity expressed in the Levine symptom severity scores had appeared to be the strongest predictor of better outcomes of surgery for carpal tunnel syndrome.
Wichtige Entscheidungshilfen für die Pflegepraxis
Authors: Zergiebel Dominik , Burckhardt Marion , Boche Ruth
Published: March 2020

Um in der täglichen Pflegepraxis die aktuell besten Entscheidungen zu treffen, sind Leitlinien und Standards eine wertvolle und unverzichtbare Hilfe. Der Schwerpunktbeitrag dieser Ausgabe informiert aus Sicht der Pflege umfassend über deren Aufbau, Entstehung und Entwicklung, klärt über Unterschiede und Gemeinsamkeiten auf und zeigt, was die Existenz dieser Schriftstücke für die Arbeit der Pflegekräfte bedeutet.
Lokal ablative Therapie bei Lebertumoren
Authors: Fischbach Frank , Ricke Jens , Fischbach Katharina
Published: March 2020

In den letzten Jahren stehen bei Patienten mit Lebertumoren interdisziplinäre Therapieansätze mit Betonung minimalinvasiver Verfahren zur Reduktion der Tumorlast zunehmend im Fokus. Lokal ablative Verfahren zur Behandlung des HCC und von Lebermetastasen kolorektaler Tumoren sind bereits in Behandlungsempfehlungen und Leitlinien integriert. Der folgende Beitrag stellt die häufigsten Verfahren vor und beschreibt ihre Relevanz für den klinischen Alltag.
Sprachstand 4-jähriger Kinder mit Migrationshintergrund in Hessen: quo vadis?
Authors: Zaretsky Eugen , Lange Benjamin P. , Hey Christiane
Published: March 2020

Die nachhaltige Integration von Personen mit Migrationshintergrund ist aktueller denn je. Dabei steht die Bedeutung der Sprache als zentraler Aspekt außer Diskussion. Im Jahr 2018 waren in Hessen ca. 1 091 000 Personen mit nicht deutscher Staatsangehörigkeit registriert. Insgesamt zeigt damit jeder dritte Hesse Migrationshintergrund, im Vorschulalter sogar jeder zweite. Die Tendenz ist angesichts der anhaltenden Einwanderung und der höheren Geburtenrate in nicht deutschen Familien steigend, und damit auch die Zahl der einschulungspflichtigen Kinder mit minimalen Deutschkenntnissen, aber auch mit klinisch abklärungsbedürftigen sprachbezogenen medizinischen Auffälligkeiten wie periphere Hörstörungen. Das Ziel der vorliegenden Studie ist die Bestandsaufnahme der Deutschkenntnisse bei 4-jährigen Kindergartenkindern mit Migrationshintergrund in Hessen, gemessen an Ergebnissen des validierten, normierten Tests „Kindersprachscreening“. Bei klinisch abklärungsbedürftigen Kindern wurde geprüft, inwiefern sie therapeutisch versorgt wurden, ob bereits diagnostizierte Störungen bzw. Krankheiten bei ihnen vorlagen und inwiefern der Therapiebedarf den Kindergarten-ErzieherInnen und Eltern bewusst war.
Qualitätsindikatoren im Notarzteinsatz
Authors: Ramadanov Nikolai , Klein Roman , Aguilar Valdez Abner Daniel , Behringer Wilhelm
Published: March 2020

Hintergrund Qualitätsindikatoren sind besonders im Notarzteinsatz, der häufig lebensrettenden Charakter hat, von großer Wichtigkeit.

Ziel der Studie Das Ziel war, die Übereinstimmung zwischen notärztlicher Verdachtsdiagnose und Krankenhausentlassungsdiagnose und die diagnosebezogene Behandlungsdauer zu ermitteln, um zu prüfen, ob diese als Qualitätsindikatoren herangezogen werden können.

Material und Methoden 708 Notarzteinsatzprotokolle des Notarztstandorts Bad Belzig im Zeitraum vom 01.07.2013 bis 30.06.2014 und 01.01.2015 bis 31.12.2015 wurden inkludiert. Die Ermittlung der dÜ (diagnostischen Übereinstimmung) erfolgte durch den Konsens dreier erfahrener Notfallmediziner. Die Behandlungsdauer wurde als Zeitintervall zwischen dem Zeitpunkt des Eintreffens des Notarztes und seiner Abfahrt vom Einsatzort berechnet. Die Behandlungsdauer wurde mittels des Mann-Whitney-U-Tests auf signifikante Unterschiede mit weiteren Variablen getestet. Aus der dÜ und der Behandlungszeit konnte die diagnostische Effizienz im Notarzteinsatz (dEffNA) ermittelt werden.

Ergebnisse Die dÜ lag in 69,4% der Fälle vor. Die durchschnittliche Behandlungsdauer alle Einsätze dauerte 21 min. Die dEffNA ergab einen Durchschnittswert für alle Diagnosen von 3,3/min. Der beste Wert für die dEffNA (dEffNA-kurz) unter den 5 untersuchten einsatzbezogenen Entlassungsdiagnosen betrug 13/min für Apoplex und der schlechteste (dEffNA-lang) 1,15/min für hypertensive Entgleisung/Krise. Die Korrektheit der Notarztdiagnose schien unabhängig von der Behandlungsdauer zu sein.

Diskussion Die dEffNA, berechnet aus dÜ und Behandlungszeit, kann als Qualitätsindikator in der präklinischen Notfallmedizin herangezogen werden. Mit dessen Hilfe können problematische Behandlungsfälle identifiziert werden.
Zertifizierung: Dermatochirurgie für Pflegekräfte und Fachangestellte (DDA, BVDD, DGDC)
Authors: Löser C. R. , Gauglitz G. , Dirschka T.
Published: March 2020

Pflegekräfte und medizinische Fachangestellte waren in der Weiterbildung auf dermatologischen Fachkongressen hinsichtlich der Dermatochirurgie lange unterrepräsentiert. Dabei spielen sie eine wichtige Rolle in der Verwirklichung einer patientenzentrierten und qualitätsgesicherten ambulanten Versorgung, gerade bei operativen Eingriffen. Deshalb wurden bereits seit 2011 in Zusammenarbeit mit der Deutschen Gesellschaft für Dermatochirurgie (DGDC) dermatochirurgische Weiterbildungsseminare für Pflegekräfte und Fachangestellte auf der jährlichen Fortbildungsveranstaltung in Frankenthal (heute „Derm“) angeboten. Diese Seminare waren nicht nur ausgezeichnet frequentiert, sondern erfreuten sich einer engagierten Mitarbeit der Teilnehmer und haben so zu einer Bedarfsanalyse beigetragen. Auf den gewonnenen Erfahrungen der Interaktion mit den Seminarteilnehmern basiert dieses Curriculum. Zunächst werden die Themen angelehnt an den Praxisablauf chronologisch aufgelistet und im zweiten Abschnitt inhaltlich präzisiert.
Is Catheter Ablation Better Than Antiarrhythmic Drugs for the Treatment of Atrial Fibrillation?
Authors: Natarajan Balaji , Nayak Srishti , Pai Ramdas G.
Published: March 2020

Long-standing atrial fibrillation is associated with significant morbidity including stroke and development of heart failure. Patients also report poor quality of life as a result of debilitating symptoms or treatment side effects from antiarrhythmic medications. Radio frequency or cryothermal mediated catheter ablation has a central role in the management of symptomatic patients with paroxysmal or persistent atrial fibrillation. Circumferential pulmonary vein isolation is vital to the success of this therapy and other ancillary techniques have been described, especially for persistent atrial fibrillation. Several randomized controlled studies have been reported over the last two decades studying important clinical outcomes in patients with atrial fibrillation. In this article, we aim to provide a review of the major studies that have helped define the role of catheter ablation in the management of symptomatic atrial fibrillation in patients with both diseased and structurally normal hearts.
Detecting Social and Behavioral Determinants of Health with Structured and Free-Text Clinical Data
Authors: Feller Daniel J. , Bear Don't Walk IV Oliver J. , Zucker Jason , Yin Michael T. , Gordon Peter , Elhadad Noémie
Published: March 2020

Background Social and behavioral determinants of health (SBDH) are environmental and behavioral factors that often impede disease management and result in sexually transmitted infections. Despite their importance, SBDH are inconsistently documented in electronic health records (EHRs) and typically collected only in an unstructured format. Evidence suggests that structured data elements present in EHRs can contribute further to identify SBDH in the patient record.

Objective Explore the automated inference of both the presence of SBDH documentation and individual SBDH risk factors in patient records. Compare the relative ability of clinical notes and structured EHR data, such as laboratory measurements and diagnoses, to support inference.

Methods We attempt to infer the presence of SBDH documentation in patient records, as well as patient status of 11 SBDH, including alcohol abuse, homelessness, and sexual orientation. We compare classification performance when considering clinical notes only, structured data only, and notes and structured data together. We perform an error analysis across several SBDH risk factors.

Results Classification models inferring the presence of SBDH documentation achieved good performance (F1 score: 92.7–78.7; F1 considered as the primary evaluation metric). Performance was variable for models inferring patient SBDH risk status; results ranged from F1 = 82.7 for LGBT (lesbian, gay, bisexual, and transgender) status to F1 = 28.5 for intravenous drug use. Error analysis demonstrated that lexical diversity and documentation of historical SBDH status challenge inference of patient SBDH status. Three of five classifiers inferring topic-specific SBDH documentation and 10 of 11 patient SBDH status classifiers achieved highest performance when trained using both clinical notes and structured data.

Conclusion Our findings suggest that combining clinical free-text notes and structured data provide the best approach in classifying patient SBDH status. Inferring patient SBDH status is most challenging among SBDH with low prevalence and high lexical diversity.
Unraveling the Influence of Common von Willebrand factor variants on von Willebrand Disease Phenotype: An Exploratory Study on the Molecular and Clinical Profile of von Willebrand Disease in Spain Cohort
Authors: Borràs Nina , Garcia-Martínez Iris , Batlle Javier , Pérez-Rodríguez Almudena , Parra Rafael , Altisent Carme , López-Fernández María Fernanda , Costa Pinto Joana , Batlle-López Fernando , Cid Ana Rosa , Bonanad Santiago , Cabrera Noelia , Moret Andrés , Mingot-Castellano María Eva , Navarro Nira , Pérez-Montes Rocío , Marcellini Shally , Moreto Ana , Herrero Sonia , Soto Inmaculada , Fernández-Mosteirín Núria , Jiménez-Yuste Víctor , Alonso Nieves , de Andrés-Jacob Aurora , Fontanes Emilia , Campos Rosa , Paloma María José , Bermejo Nuria , Berrueco Rubén , Mateo José , Arribalzaga Karmele , Marco Pascual , Palomo Ángeles , Castro Quismondo Nerea , Iñigo Belén , del Mar Nieto María , Vidal Rosa , Martínez María Paz , Aguinaco Reyes , Tenorio Maria , Ferreiro María , García-Frade Javier , Rodríguez-Huerta Ana María , Cuesta Jorge , Rodríguez-González Ramón , García-Candel Faustino , Dobón Manuela , Aguilar Carlos , Corrales Irene , Vidal Francisco
Published: March 2020

The clinical diagnosis of von Willebrand disease (VWD), particularly type 1, can be complex because several genetic and environmental factors affect von Willebrand factor (VWF) plasma levels. An estimated 60% of the phenotypic variation is attributable to hereditary factors, with the ABO blood group locus being the most influential. However, recent studies provide strong evidence that nonsynonymous single nucleotide variants (SNVs) contribute to VWF and factor VIII phenotypic variability in healthy individuals. This study aims to investigate the role of common VWF SNVs on VWD phenotype by analyzing data from 219 unrelated patients included in the “Molecular and Clinical Profile of von Willebrand Disease in Spain project.” To that end, generalized linear mixed-effects regression models were fitted, and additive and epistatic analyses, and haplotype studies were performed, considering five VWD-related measures (bleeding score, VWF:Ag, VWF:RCo, factor VIII:C, and VWF:CB). According to these analyses, homozygotes: for p.Thr789Ala(C) would be expected to show 39% higher VWF:Ag levels; p.Thr1381Ala(C), 27% lower VWF:Ag levels; and p.Gln852Arg(C), 52% lower VWF:RCo levels. Homozygotes for both p.Thr789Ala(C) and p.Gln852Arg(T) were predicted to show 185% higher VWF:CB activity, and carriers of two copies of the p.Thr1381Ala(T)/p.Gln852Arg(T) haplotype would present a 100% increase in VWF:RCo activity. These results indicate a substantial effect of common VWF variation on VWD phenotype. Although additional studies are needed to determine the true magnitude of the effects of SNVs on VWF, these findings provide new evidence regarding the contribution of common variants to VWD, which should be taken into account to enhance the accuracy of the diagnosis and classification of this condition. ClinicalTrials.gov identifier: NCT02869074.
Endothelial CD40 Mediates Microvascular von Willebrand Factor-Dependent Platelet Adhesion Inducing Inflammatory Venothrombosis in ADAMTS13 Knockout Mice
Authors: Tahir Sibgha , Wagner Andreas H. , Dietzel Steffen , Mannell Hanna , Pircher Joachim , Weckbach Ludwig T. , Hecker Markus , Pohl Ulrich
Published: March 2020

Background von Willebrand factor (vWF) plays an important role in platelet activation. CD40–CD40 ligand (CD40L) induced vWF release has been described in large vessels and cultured endothelium, but its role in the microcirculation is not known. Here, we studied whether CD40 is expressed in murine microvessels in vivo, whether CD40L induces platelet adhesion and leukocyte activation, and how deficiency of the vWF cleaving enzyme ADAMTS13 affects these processes.

Methods and Results The role of CD40L in the formation of beaded platelet strings reflecting their adhesion to ultralarge vWF fibers (ULVWF) was analyzed in the murine cremaster microcirculation in vivo. Expression of CD40 and vWF was studied by immunohistochemistry in isolated and fixed cremasters. Microvascular CD40 was only expressed under inflammatory conditions and exclusively in venous endothelium. We demonstrate that CD40L treatment augmented the number of platelet strings, reflecting ULVWF multimer formation exclusively in venules and small veins. In ADAMTS13 knockout mice, the number of platelet strings further increased to a significant extent. As a consequence extensive thrombus formation was induced in venules of ADAMTS13 knockout mice. In addition, circulating leukocytes showed primary and rapid adherence to these platelet strings followed by preferential extravasation in these areas.

Conclusion CD40L is an important stimulus of microvascular endothelial ULVWF release, subsequent platelet string formation and leukocyte extravasation but only in venous vessels under inflammatory conditions. Here, the lack of ADAMTS13 leads to severe thrombus formation. The results identify CD40 expression and ADAMTS13 activity as important targets to prevent microvascular inflammatory thrombosis.
Early Onset Severe Hypertensive Disease in Pregnancy and Screening for Antiphospholipid Syndrome
Authors: Sobhani Nasim C. , Shulman Rachel , Tran Erin E. , Gonzalez Juan M.
Published: March 2020

Objective Although preterm delivery (PTD) before 34 weeks for severe hypertensive disease is a diagnostic criterion for antiphospholipid syndrome (APS), there is no consensus regarding testing for antiphospholipid antibodies (aPL) in this setting. We aim to describe the frequency of and the characteristics associated with inpatient aPL testing in this population.

Study Design In this retrospective study of PTD before 34 weeks for severe hypertensive disease, charts were reviewed for aPL testing, gestational age at delivery, fetal complications, and severity of maternal disease. Wilcoxon rank-sum test, Fisher's exact, and chi-squared tests were used for analyses of continuous and categorical variables, and multivariate logistic regression for adjusted odds ratios.

Results Among 133 cases, 14.3% had APS screening via aPL testing. Screened patients delivered earlier than unscreened patients (28.9 vs. 31.7 weeks, p <0.001). Each additional week of gestation was associated with a 39% decrease in the odds of screening (95% confidence interval: 0.43–0.85). There were no other differences between the groups.

Conclusion APS screening after PTD for severe hypertensive disease is uncommon but more likely with earlier PTD. Despite conflicting recommendations from professional organizations, prior studies demonstrate contraceptive, obstetrical, and long-term risks associated with APS, suggesting that we should increase our screening efforts.
Persistence and Extent of Neonatal Brachial Plexus Palsy: Association with Number of Maneuvers and Duration of Shoulder Dystocia
Authors: Doty Morgen S. , Chauhan Suneet P. , Chang Kate W.-C. , Al-Hafez Leen , McGovern Connie , Yang Lynda J.-S. , Blackwell Sean C.
Published: March 2020

Objective The main objective of this article is to determine if persistence of neonatal brachial plexus palsy (NBPP) following shoulder dystocia was associated with maneuvers used or duration of impacted shoulder.

Study Design Retrospective review of children with NBPP and documented shoulder dystocia. Student t-tests and chi-squared tests were used to compare outcomes when shoulder dystocia resolved with > 3 versus ≤ 3 maneuvers or duration > versus ≤ 120 seconds. Relative risk (RR) with 95% confidence intervals (CI) was calculated.

Results Among 46 children with NBPP and shoulder dystocia, incidence of persistence was significantly higher at 2 years of age when > 3 versus ≤ 3 maneuvers were used (100 vs. 62%; RR: 1.6, 95% CI: 1.2–2.2). When resolution of impacted shoulder lasted >120 versus ≤ 120 seconds, NBPP at 2 years was significantly more likely (100 vs. 63%; RR: 1.6, 95% CI: 1.1–2.2). Injury to all five nerves of the brachial plexus was more likely if standard deviation lasted > 120 versus ≤ 120 seconds (RR: 2.2; 95% CI: 1.03–4.6).

Conclusion Though the number of maneuvers used and duration of shoulder dystocia are associated with persistence of NBPP, the retrospective nature of the study of a selective cohort precludes recommendations changing the current management of shoulder dystocia.
Hydrodynamics of a particle model in contact with stochastic reservoirs
Authors: Tkachov Pasha
Published: March 2020

We consider an exclusion process with finite-range interactions in the microscopic interval [0, N]. The process is coupled with the simple symmetric exclusion processes in the intervals [−N, −1] and [N + 1, 2N], which simulate reservoirs. We show that an average of the empirical densities of the processes speeded up by the factor N2 converge to solutions of parabolic partial differential equations inside [−N, −1], [0, N], and [N + 1, 2N], which correspond to the macroscopic intervals (−1, 0), (0, 1), and (1, 2). Since the total number of particles is preserved by the evolution, we obtain the Neumann boundary conditions on the external boundaries u = −1, u = 2 of the reservoirs. Finally, a system of Neumann and Dirichlet boundary conditions is derived at the interior boundaries u = 0, u = 1 of the reservoirs.
An electromagnetic separation system for the enrichment of 39Ar
Authors: Jia Z. H. , Tong Amin. L. , Sun L. T. , Liu Y. G. , Liu J. L. , Wu Q. , Fang X. , Yang W. S. , Guo Y. H. , Ritterbusch F. , Lu Z.-T. , Jiang W. , Yang G. M. , Chen Q. W.
Published: March 2020

An isotope enrichment system for 39Ar has been developed at the Institute of Modern Physics, which is designed to increase the abundance of 39Ar in the incident sample gas. With intense Ar+ beams produced by a 2.45 GHz electron cyclotron resonance ion source and a high mass resolution spectrometer system, Ar isotopes are evidently separated on the target plane and selectively collected by an Al target. The separated Ar isotopes have been identified on the target plane, which is consistent with the simulations. According to the recent cross-checked results with atom trap trace analysis, a high enrichment factor of 39Ar has been successfully achieved. This paper will present the design and test results of this system.
The effects of interstitial iodine in hybrid perovskite hot carrier cooling: A non-adiabatic molecular dynamics study
Authors: Banerjee Swastika , Kang Jun , Zhang Xiuwen , Wang Lin-Wang
Published: March 2020

Understanding the defect chemistry of lead-halide perovskites and its effects on the hot-carrier lifetime is of significance for both fundamental understanding and applications as solar cell light absorbing materials. In this study, the mechanistic details of hot carrier decay in hybrid perovskites are investigated using a newly developed non-adiabatic molecular dynamics method. In this approach, the nuclear trajectory is based on Born–Oppenheimer ground state molecular dynamics, which is then followed by the evolution of carrier wave function including the detailed balance and decoherence effects. We found the longer decay time for hot electrons due to the incorporation of interstitial iodine in the hybrid lead-halide perovskites (MAPbI3), while the hot hole decay time is not affected significantly by the interstitial iodine. The underlying mechanism for such modulation of hot carrier dynamics is attributed to the changes of carrier density of states and the electron–phonon coupling strength. Hence, iodine interstitial is the necessary condition to create long-lived hot electrons in perovskites, which is further demonstrated by the comparative analysis with the pure MAPbI3.
Consensus-based distribution of power packets and decentralized control for routing
Authors: Baek Seongcheol , Ando Hiroyasu , Hikihara Takashi
Published: March 2020

A power packet distribution network is expected to be one of the advanced power distribution systems, providing high controllability in both energy management and failure management. Regarding network operations, the power packet transmission is governed by switching operation within each of the routers. Here, the power distribution through power packets exhibits consensus-like dynamical behaviors. These features lead to the question of a consensus dynamics on switching topology and routing controls for appropriate power flows. Our approach to the above subjects is based on the dynamical modeling and the emulation of dynamics through the decentralized control of routers. The simulations on a ring-structure network, of the power distribution, reveal that the dynamical solution of the unbiased distribution is feasible via the decentralized control, while in the biased case, the result shows two behavioral fragments, which is quite different from the dynamical solution. In this discussion, we propose a decentralized algorithm that contains only fundamental functions for the packet transmission and is able to be redesigned or extended for further applications.
Novel freeze-casting device with high precision thermoelectric temperature control for dynamic freezing conditions
Authors: Christiansen Cathrine D. , Nielsen Kaspar K. , Bjørk Rasmus
Published: March 2020

A novel freeze-casting device utilizing a thermoelectric element for high precision temperature control allowing for dynamic freezing conditions of freeze-cast materials is presented. Freeze-casting is a processing route for producing materials of anisotropic porosity in the form of aligned and well-defined microchannels. In freeze-casting, particulates of a material are suspended in a fluid and a thermal gradient is applied across for directional freezing. Controlling the thermal gradient across the suspension amounts to controlling the kinetics and freezing direction in the suspension and thus the resulting structural features and dimensions of the microchannels. The performance of the device presented here was evaluated by directional freezing of both water and aqueous ceramic suspension samples using both linear and exponential freezing profiles. The freezing front was successfully tracked by continuously measuring the temperature gradient along the sample using thermocouples directly mounted on the freeze-casting mold. The current minimum operational temperature of the freeze-caster is ∼220 K, with freezing front velocities in the range of ∼5 μm/s to 30 μm/s for sample lengths of 5 mm–25 mm.
Microparticle cloud imaging and tracking for data-driven plasma science
Authors: Wang Zhehui , Xu Jiayi , Kovach Yao E. , Wolfe Bradley T. , Thomas Edward , Guo Hanqi , Foster John E. , Shen Han-Wei
Published: March 2020

Oceans of image and particle track data encountered in plasma interactions with microparticle clouds motivate development and applications of machine-learning (ML) algorithms. A local-constant-velocity tracker, a Kohonen neural network or self-organizing map, the feature tracking kit, and U-Net are described and compared with each other for microparticle cloud datasets generated from exploding wires, dusty plasmas, and atmospheric plasmas. Particle density and the signal-to-noise ratio have been identified as two important factors that affect the tracking accuracy. Fast Fourier transform is used to reveal how U-Net, a deep convolutional neural network developed for non-plasma applications, achieves the improvements for noisy scenes. Viscous effects are revealed in the ballistic motions of the particles from the exploding wires and atmospheric plasmas. Subdiffusion of microparticles satisfying Δr2∝tk (k=0.84±0.02) is obtained from the dusty plasma datasets. Microparticle cloud imaging and tracking, when enhanced with data and ML models, present new possibilities for plasma physics.