bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive Exponential Finite Elements for a Phase Field Fracture Model
Authors: Olesch Darius , Kuhn Charlotte , Schlülter Alexander , Müller Ralf
Published: December 2021

Fracture phenomena can be described by a phase field model in which an independent scalar field variable in addition to the mechanical displacement is considered [3]. This field approximates crack surfaces as a continuous transition zone from a value that indicates intact material to another value that represents the crack. For an accurate approximation of cracks, narrow transition zones resulting in steep gradients of the fracture field are required. This necessitates a high mesh density in finite element simulations, which leads to an increased computational effort. In order to circumvent this problem without forfeiting accuracy, exponential shape functions were introduced in the discretization of the phase field variable, see [4]. These special shape functions allow for a better approximation of steep gradients of the phase field with less elements as compared to standard Lagrange elements. Unfortunately, the orientation of the exponential shape functions is not uniquely determined and needs to be set up in the correct way in order to improve the approximation of smooth cracks. This work solves the issue by adaptively reorientating the exponential shape functions according to the nodal values of the phase field gradient in each element. Furthermore, a local approach is pursued that uses exponential shape function only in the vicinity of the crack, whereas standard bilinear shape function are used away from the crack.
Rational Functions for the Reconstruction of Exponential Sums from their Fourier Coefficients
Authors: Petz Markus , Plonka Gerlind , Derevianko Nadiia
Published: December 2021

We look closer at the type of rational functions involved in reconstructing exponential sums from their Fourier coefficients.
Coarse‐graining via EDP‐convergence for linear fast‐slow reaction‐diffusion systems
Authors: Stephan Artur
Published: December 2021

In [7] a fast‐reaction limit for a linear reaction‐diffusion system consisting of two diffusion equations coupled by a linear reaction is performed. The linear reaction‐diffusion system is understood as a gradient flow of the free energy in the space of probability measures equipped with a geometric structure, which contains the Wasserstein metric for the diffusion part and cosh‐type functions for the reaction part. The fast‐reaction limit is done on the level of the gradient system by proving EDP‐convergence with tilting. The limit gradient system induces a diffusion system with Lagrange multipliers on the linear slow‐manifold. Moreover, the limit gradient system can be equivalently described by a coarse‐grained gradient system, which induces a scalar diffusion equation with a mixed diffusion constant for the coarse‐grained slow variable.
Phase field modeling of crack nucleation and propagation in martensitic micro–structures
Authors: Borzabadi Farahani Ehsan , Juhre Daniel
Published: December 2021

In this paper, a combined phase‐field (PF) approach has been considered to model fracture behavior under martensitic transformation effects. The effect of temperature as another degree of freedom has been studied, which has not been taken into account in previous studies. The concept of thermodynamic driving force, the elastic energy, interfacial energy, heat transfer and the kinetics of phase field equations are introduced to obtain the fracture domain, the martensitic evaluation, the temperature field and displacements [1]. Due to the high amount of stress at the crack tip, the martensitic transformation can start and propagate through the austenitic structure. The internal stresses between martensitic and austenitic layers deviate the crack path, leading to changes in the martensitic formation [2]. In addition, temperature plays an important role in this phenomenon in two aspects; first of all a change in temperature can produce thermal stress; and secondly, it affects the conditions for martensitic transformation. An increase in temperature requires more energy for the phase transformation [3], and changes in martensitic formation induce a new driving force for crack growth [2,4].
Prediction of the anisotropic crack resistance of heterogeneous microstructures using a crack phase‐field model
Authors: Hansen-Dörr Arne Claus , Kästner Markus
Published: December 2021

In this contribution, a variational crack phase‐field model for heterogeneous materials is used to study periodic microstructures. The discontinuity at material interfaces is taken into account by an additional static order parameter. A partial rank‐I relaxation ensures the pointwise fulfillment of the Hadamard jump condition and static equilibrium within the diffuse interface. Crack propagation is investigated for different orientations of hexagonal microstructures and various phenomena like toughening‐by‐weakening and an orientation‐dependent fracture toughness are observed.
Nonlocal damage modelling for finite element simulations of ductile steel sheets under multiaxial loading
Authors: Nahrmann Marvin , Matzenmiller Anton
Published: December 2021

The finite element simulation of forming processes or vehicle crash scenarios involves multiaxial loading conditions in general. Thereby, damage and failure in ductile steel sheets is triggered by void growth under hydrostatic tensile loading or by void elongation within a narrow band under shear dominated loading. These different damage mechanisms are considered by a stress state dependent continuum damage model. The damage initiation and failure are represented by a critical and a failure strain. Both are HOSFORD‐COULOMB type functions of the stress triaxiality and the LODE parameter and, thus, incorporate the stress state dependence of the damage mechanisms. Due to the pathological mesh sensitivity for continuum damage models, an enhancement towards nonlocal damage evolution is carried out. Thereby, two options are investigated and compared: the integral nonlocal formulation and the gradient enhanced approach. Finally, the proposed nonlocal ductile damage model is verified for a wide range of stress states by test data of various tensile and shear specimens.
Forward dynamics simulation of a human leg model with a geometrically exact beam model as prosthetic foot.
Authors: Scheiterer Eduard S. , Leyendecker Sigrid
Published: December 2021

In this work, we present a model for a human leg with a prosthetic foot, consisting of rigid bodies for the thigh and shank and a geometrically exact beam model for the prosthesis. The prosthesis is modelled after the Össur Vari‐Flex® carbon spring prosthetic foot. The individual bodies are connected by joints imposing constraints, mimicking the motions of human joints. A structure preserving variational integrator is used to calculate the forward dynamic simulation of the model and to analyse the energy exchange between potential, kinetic and deformation energy. Due to the variational integrator, there is no artificial energy loss introduced by the numerical integration over the simulation time [3].
Dynamic simulation of the Wilberforce pendulum using constrained spatial nonlinear beam finite elements
Authors: Harsch Jonas , Capobianco Giuseppe , Eugster Simon R.
Published: December 2021

More than 100 years ago, Lionel Robert Wilberforce did investigations On the Vibrations of a Loaded Spiral Spring [1]. The spring was clamped at its upper side and on the other side, perpendicular to the spring axis, a steel cylinder was attached. Four screws with adjustable nuts were symmetrically attached around the cylinder in order to change its moment of inertia (Fig. 1). In this paper the Wilberforce pendulum is modeled by a rigid body attached to a constrained spatial nonlinear Timoshenko beam, discretized with B‐spline shape functions. As shown by a numerical experiment, the presented model is capable of reproducing the characteristic pendulum motion.
Simulation of ductile crack propagation in metal matrix composites ‐ Comparison with cyclic experiments
Authors: Wingender Dennis , Brackmann Lukas , Röttger Arne , Balzani Daniel
Published: December 2021

The efficient operation of mechanized tunnel drilling machines is strongly determined by the wear resistance of the applied mining tools. Especially in chisels, but also partly in cutting disks, metal matrix composites are used. Their wear mechanism is dominated by surface spalling, i.e. subcritical crack propagation through the material's microstructure, mainly consisting of a ductile metal matrix and carbide inclusions. Since this process is primarily governed by the morphology of the microstructure and the mechanical behavior of the individual phases, simulations at the microscale enable the design of improved materials. In this contribution, a method for the modeling of this process is presented. The approach is based on the eigenerosion framework introduced in [1] and an algorithmic scheme for large strains is given, which extends the small strain implementation in [2]. For the phases at the microscale, the finite strain plasticity formulation [3] is applied. Examples according to [4] are shown in order to demonstrate the mesh independence of the framework for ductile crack propagation. Furthermore, simulations are carried out on the microscale by applying the Finite Cell Method [5] on metal matrix composite microstructures. Here, a specific cell arrangement is constructed which minimizes the required number of cells for a given microstructure morphology. Additionally, an experimental setup for the validation of the eigenerosion framework on the microscale is presented. By evaluating the results of these simulations, failure of the material can be investigated on a microscopic level and improvements of the material morphology regarding wear can be realized.
Multiscale modeling of calcified hydrogel networks
Authors: Aygün Serhat , Klinge Sandra
Published: December 2021

The model proposed simulates the effective material behavior of calcified hydrogels using the multiscale finite element method (FEM). To this end, representative volume elements (RVEs) are generated to depict the biphasic material microstructure consisting of the organic hydrogel and inorganic calcium phosphate. The choice of the hydrogel matrix influences the type of agglomeration of the inorganic phase and thus dictates the geometry of the RVE. Most commonly, the inorganic phase appears in the form of spherical inclusions or honeycomb grids where the characteristic size of a typical unit may vary. The approach proposed treats the calcified regions as Neo‐Hookean material and assumes the Ogden model for the hydrogel. The contribution closes with the numerical results on the effective material behavior and their validation with respect to experimental findings.
Simulation of the dynamic properties of open cell foams by means of a macroscopic stochastic model
Authors: Kirchhof Stephan , Ams Alfons
Published: December 2021

Open cell foams are widely used in engineering which includes an application in areas, where vibration excitations can act on the structures. Therefore dynamical properties as eigenfrequencies and eigenmodes are of particular interest, which show a dispersion due to the stochastic characteristic of the microstructure. To avoid time consuming measurements a simulation algorithm will be presented which enables to estimate the distribution of the eigenfrequencies. In order to do this the microstructure has to be addressed as well as different weights of several specimen, which have an influence on the computed and measured eigenfrequencies.
Plate theories: A‐priori fulfillment of the local conditions by the consistent‐approximation approach
Authors: Meyer-Coors Michael , Kienzler Reinhold , Schneider Patrick
Published: December 2021

Classical plates theories, like Kirchhoff's plate theory [1], are based on kinematical a‐priori assumptions. Avoiding these assumptions, we derive from the three‐dimensional theory of linear elasticity by means of Taylor‐series expansions the quasi two‐dimensional problem. This problem consists of infinitely many partial‐differential equations (PDEs) written in infinitely many displacement coefficients. With the consistent approximation approach we arrive at solvable hierarchical plate theories. By using the modular structure of the displacements coefficients (modularity), we obtain from these generic‐plate theories the complete‐plate theories, whose results fulfill the strong form of the local equilibrium conditions and the Neumann boundary conditions on the upper and lower face of the plate (local conditions) a‐priori. Furthermore, we show that every variable of the complete‐plate theories can be calculated.
Curvature sensing of a soft robot based on conductive foam
Authors: Grube Malte , Seifried Robert
Published: December 2021

Soft material robots are an emerging and fast‐growing field of research [1] with potential application in various technical fields. These applications include, but are not limited to medical applications and all sorts of human‐machine‐interaction. Due to the soft structure, conventional components and design methodologies are not applicable. For reliable control and positioning of soft robots in 3D space especially accurate knowledge about their current position and orientation is essential.

In this contribution, a resistive curvature sensor for a soft robot is presented. It is based on electrically conductive foam attached to the soft robot. Deformations of the foam lead to a change in electrical resistance [2] which can be measured and used to determine the curvature of a soft robot. Since the sensor behavior is nonlinear and hysteretic, a neural network is used to determine the curvature of the soft robot from the measured foam resistances.
A Mixed Acoustic Fluid Finite Element in Boundary Representation for Fluid‐Structure Interaction
Authors: Sauren Bjorn , Klarmann Simon , Klinkel Sven
Published: December 2021

This contribution focuses on a mixed finite element formulation for an acoustic fluid in boundary representation to model fluid‐structure interaction problems. In fact, acoustic fluids are characterized by their lack of dynamic viscosity and undergo displacements through a pure pressure wave propagation. Since many fluids, for instance water, show nearly‐incompressible behavior, volumetric locking occurs in the classical finite element formulation. This drawback is herein evaded by a two‐field, or mixed, finite element formulation. To facilitate the contact condition at the fluid‐structure interface, the acoustic fluid is expressed by structural field variables, which are nodal displacements and internal pressures. Both the displacements and internal pressures are parameterized by a Scaled‐Boundary (SB) approach, in which an interpolation in the scaling direction is employed. From this parametrization, the element mass and stiffness matrices of the fluid can be formulated. Due to the special parametrization of the element boundary, pressure continuity is required between scaled sections in the element interior, although pressure continuity may be interrupted between neighboring Scaled‐Boundary elements. Since the lack of shear viscosity leads to unwanted zero‐energy modes concerned with the fluid's vorticity, this vorticity is penalized on a sectional level. As a result, these modes do not show up in the frequency spectrum of the dynamic eigenvalue problem any longer. The natural frequencies and mode shapes in this spectrum deliver accurate results, even for very coarse meshes.
Configurational Forces in Bond Order Potentials
Authors: Birang O. S. Elmira , Smith Ana-Suncana , Steinmann Paul
Published: December 2021

In this contribution, a configurational mechanics framework is elaborated to assess the applicability of atomistic configurational forces in fracture of crystalline lattices. To this end, an analytical interatomic potential is reformulated in terms of the material positions occupied by the atoms participating in two‐ and three‐body interactions. It is demonstrated that such a potential satisfies the requirements of invariances i.e., translational, rotational and parity. The focus of this work is developing the configurational setting for the bond order Tersoff potential. Two‐dimensional pre‐cracked mono‐layer graphene modelled with the Tersoff potential is chosen to study the configurational force approach in determining energy release during crack propagation into the lattice.
Coupling conditions and stability of transport networks
Authors: Borsche Raul , Eimer Matthias
Published: December 2021

In transport networks the choice of coupling conditions has a large impact on the smoothness of the solution. This work illustrates an alternative to the algebraic instant mixing, which is used in most applications. The ODE formulation of the coupling enables the stability of solutions and Lipschitz continuous dependence on the velocity.
Frequency analysis of transversal vibrations of belt drives with time‐varying belt lengths
Authors: Schnürer Dominik , Holl Helmut J.
Published: December 2021

The dynamic positioning accuracy and the smoothness are key aspects of linear belt drives where vibrations have a negative impact. A FE‐Model, based on a one‐dimensional analytical model of the belt, is derived to study the respective effects for different parameters. The model considers the dominant transverse deflection and a quasi‐static assumption for the longitudinal deformation. The possibility to consider various time‐varying belt lengths, the belt mass, stiffness and tension force is an essential part of the modeling. The non‐linear cable effect is demonstrated by comparison with the linearized solution. Vibrations for the cases of constant and variable belt length are investigated and compared to common in literature used approximation formulas for the resonance frequencies of such systems. The influence on positioning deviations and the use of vibration reduction techniques considering the different belt sections of the linear drive can be derived from the computed results and are topics for future research.
Application of a continuum‐mechanical tumour model to brain tissue
Authors: Suditsch M. , Lambers L. , Ricken T. , Wagner A.
Published: December 2021

Brain tumours are among the most serious diseases of our time. A continuum‐mechanical model is proposed to represent the basic processes of growth and regression. The physical multi‐constituent approach is derived in the framework of the Theory of Porous Media (TPM). This modelling approach can be expressed mathematically via strongly coupled partial differential equations (PDEs), that are solved using the well‐known Finite Element Method with the software toolkit FEniCS. A realistic initial‐boundary‐value problem is used to demonstrate the workflow with the used software and the capabilities of the model.
Simulation of fatigue crack growth in residual‐stress‐afflicted specimen with a phase‐field model
Authors: Seiler Martha , Keller Sören , Kashaev Nikolai , Klusemann Benjamin , Kästner Markus
Published: December 2021

Laser shock peening (LSP) is a promising technique to systematically introduce local compressive residual stresses in metal sheets, inhibiting fatigue cracks in these areas. We model fatigue crack growth in these specimen with the help of a phase‐field model for fatigue fracture [1]. First, we parametrise the model using untreated aluminium specimens. In a second step, we use the determined parameters to simulate residual‐stress‐afflicted specimens, qualitatively reproducing the crack inhibition due to LSP.
Phase field method for quasi‐static brittle fracture: an adaptive algorithm based on the dual variable
Authors: Bertrand Fleurianne
Published: December 2021

An adaptive phase field method for quasi‐static brittle fracture is developed. The adaptive refinement of the meshes is based on the error between two stresses: the discontinuous post‐processed stresses computed with the displacement approximation and a H(div) conforming dual approximation of the stresses. The algorithm is validated by solving a benchmark problem considering a plate with an edge crack subjected to tension load.
Towards the application of the One‐Dimensional Turbulence model for the evaluation of collection efficiencies in wire‐tube electrostatic precipitators
Authors: Medina Méndez Juan A. , Schmidt Heiko
Published: December 2021

The One‐Dimensional Turbulence (ODT) model framework for the simulation of particle‐laden wire‐tube electrostatic precipitators is detailed in this work by specifying initial conditions, governing equations, and the mechanism for two‐way coupling between the electrostatic fields and the hydrodynamic flow. Unlike in a previous investigation [1], a two‐way coupling is required due to the low electrical mobility of aerosol particles, making flow motion responsible for the appearance of electrical convective currents. The ultimate goal of this framework is to develop a method which is able to investigate the precipitation phenomenon in wire‐tube precipitators, e.g., the collection efficiency, while relying on highly resolved physics.
Deformations of a piezo‐actuated bearing ring in journal bearings
Authors: Bitner Alexander , Seemann Wolfgang
Published: December 2021

An elastically deformable bearing ring is investigated. The piezo‐actuated shaping of the elastic bearing ring as well as the journal motion are coupled and determine the height of the lubrication gap which takes a crucial part in the theory of hydrodynamic lubrication. The influence of the active‐dynamic shaping of the bearing ring on the rotor dynamic behaviour has been investigated in [1], especially for a two‐lobe journal bearing. The present investigations are aiming at the active‐static shaping of a bearing ring, i.e. a finite number of piezo actuators is used to cause deformations of the bearing ring. Moreover, the realisation of different shapes by the introduced piezo actuators is examined, whereas the desired shapes are not necessarily limited to two‐lobe geometries.
Greedy algorithms for image approximation from scattered Radon data
Authors: Albrecht Kristof , Iske Armin
Published: December 2021

Positive definite kernels are powerful tools for multivariate approximation from scattered data. This contribution discusses kernel‐based image approximation from scattered Radon data. To this end, we use weighted kernels for the reconstruction. Moreover, we propose greedy algorithms, which are used to adaptively select suitable approximation spaces. This reduces the complexity of the resulting image reconstruction method and, moreover, it improves the numerical stability quite significantly.
Data‐Driven Stress Prediction for Thermoplastic Materials
Authors: Pi Savall Berta , Mielke André , Ricken Tim
Published: December 2021

The present study applies two different machine learning (ML) algorithms to predict the stress‐strain mapping for the non‐linear behaviour of thermoplastic materials: a Long Short‐Term Memory (LSTM) algorithm and a Feed‐Forward Neural Network (FFNN). The approach of this work requires the generation of the stress‐strain curve for specific material parameters. The training data are obtained from the von Mises material law and the Ramberg‐Osgood equation. The four combinations of ML algorithms with constitutive laws are evaluated and show a good agreement with numerical data.
Action Principle and Ritz Method for Yarn Dynamics in Ring Spinning
Authors: Lenz Michael , Beitelschmidt Michael
Published: December 2021

Ring spinning is the most relevant method of producing high quality staple yarns. The rotating yarn forms one or multiple balloon shapes governed by inertial, eyelet friction and drag forces. Traditionally, the stationary yarn path has been computed by direct integration of an equation of motion, and stability and natural oscillations have been assessed by application of Galerkin's method to these ([1], [4], and others). Recent technological advances by using frictionless superconducting magnetic bearings allow for increased process speeds and thus motivate a renewed interest in the dynamics of ring spinning.

An integral formulation of the yarn dynamics problem is presented using Hamilton's principle for the one‐dimensional continuum and the magnetic bearing. While therefrom the known equations of motions can be deduced elegantly, here Ritz's method is employed to achieve direct discretization of the problem, with cases to be made for both local and global shape functions.

While applicable to the classical study of stationary balloon shapes and their stability, the resulting models in particular enable the study of the instationary yarn path and natural and driven yarn oscillations, which both have received limited attention in literature, but are known to affect yarn tension and thus the process viability.
On Adaptive Patankar Runge–Kutta methods
Authors: Kopecz Stefan , Meister Andreas , Podhaisky Helmut
Published: December 2021

We apply Patankar Runge–Kutta methods to y′ = M(y)y and focus on the case where M(y) is a graph Laplacian as the resulting scheme will preserve positivity and total mass. The second order Patankar Heun method is tested using four test problems (stiff and non‐stiff) cast into this form. The local error is estimated and the step size is chosen adaptively. Concerning accuracy and efficiency, the results are comparable to those obtained with a traditional L‐stable, second order Rosenbrock method.
A non‐incremental solution procedure for elastoplastic problems in structural mechanics
Authors: Bamer Franz , Shirafkan Nima , Cao Xiaodan , Oueslati Abdelbacet , Stoffel Marcus , De Saxcé Géry , Markert Bernd
Published: December 2021

In this contribution, we present a non‐incremental solution procedure for the efficient treatment of elastoplastic problems. To this end, all time history data are decoupled into space and time, and the solution is obtained using the fixed‐point algorithm.
Gaussian approximation for rooted edges in a random minimal directed spanning tree
Authors: Bhattacharjee Chinmoy
Published: December 2021

We study the total ‐powered length of the rooted edges in a random minimal directed spanning tree — first introduced in Bhatt and Roy (2004) — on a Poisson process with intensity on the unit cube for . While a Dickman limit was proved in Penrose and Wade (2004) in the case of , in dimensions three and higher, Bai, Lee and Penrose (2006) showed a Gaussian central limit theorem when , with a rate of convergence of the order . In this article, we extend these results and prove a central limit theorem in any dimension for any . Moreover, making use of recent results in Stein's method for region‐stabilizing functionals, we provide presumably optimal non‐asymptotic bounds of the order on the Wasserstein and the Kolmogorov distances between the distribution of the total ‐powered length of rooted edges, suitably normalized, and that of a standard Gaussian random variable.
Advances in Structural Modification and Pharmacological Activity of Catalpol and its Derivatives
Authors: Liu Shuanglin , Kong Yuanfang , Cai Juntao , Dong Chunhong
Published: December 2021

Catalpol and its derivatives were found in a variety of Chinese medicinal plants and possess various biological activities, such as anti‐inflammatory, anti‐oxidant, neuroprotective, cardiovascular protective, anti‐tumor and hypoglycemic and so on. The extensive pharmacological activities of catalpol have been attracted much attention to researchers, but the clinical applications are limited by poor lipid solubility, low bioavailability and short half‐life, so pharmacologists have made various structural modifications to catalpol, such as increasing lipid solubility to enhance its biological activities in the hope that it can be widely used in clinical applications. In this paper, using “Catalpol” and “Catalpol derivatives” as the keywords, more than 200 articles from 1965 to 2021 were obtained from databases, such as CNKI, PubMed, Scifinder and so on. Finally, 93 articles were selected to systematically analyze the structure and efficacy of catalpol and its derivatives according to pharmacological activity, which will provide ideas for the development of new catalpol drugs in the future.
Graphene Oxide (GO) as Sustainable Heterogeneous Carbocatalyst for Synthesis of Organic Carbamates Using Urea and Alcohols under Mild Reaction Conditions
Authors: Wabaidur Saikh Mohammad , Siddiqui Masoom Raza , Seikh Asiful H.
Published: December 2021

A 2‐Dimensional sp2‐hybridised carbon based material graphene oxide (GO) was synthesized and characterized by various instrumental techniques viz. FTIR, PXRD, Raman, FESEM and HRTEM. The metal free environmentally benign carbocatalyst was fruitfully used as catalyst for the synthesis of primary carbamates from alcohols in presence of non hazardous cheap carbonyl source urea. Both aromatic (bezylic as well as phenolic) and aliphatic alcohols produced moderate to very high yield (53–95 %) of corresponding carbamates through this catalytic reaction. The used GO catalyst is very straightforward to recover from reaction mixture via centrifugation method. The heterogeneous and reusability nature of the catalyst exists several cycles of catalytic reaction. We check six cycles of the catalytic reaction and the activity of the catalyst after 6th cycle does not alter very significantly.
Palladium‐Catalyzed Selective o‐Bromination of Mesoionic 1,3‐Diphenyltetrazolium‐5‐olate: Switching the Directing Group from Nitrogen to Oxygen
Authors: Hirashita Tsunehisa , Watanabe Harue , Harada Yuki , Kurabayashi Hideaki , Yukinobu  , Yamashita  , Oizumi Shiyogo , Araki Shuki
Published: December 2021

Pd‐catalyzed bromination of mesoionic 1,3‐diphenyltetrazolium‐5‐olate (1) was developed. In the presence of palladium acetate (5 mol%), N‐bromosuccinimide (110 mol%), and p‐toluenesulfonic acid (50 mol%) in 1,2‐dichloroethane under reflux, olate 1 underwent bromination to give 1‐(2‐bromophenyl)‐3‐phenyltetrazolium‐5‐olate in a moderate yield as the major product, indicating that the 4‐nitrogen atom acts as a directing group rather than the negatively charged oxygen atom. The X‐ray‐suitable crystals of the corresponding palladacycle were isolated from 1‐mesityl‐3‐phentytetrazolium‐5‐olate and fully characterized. When both the o‐positions of the 3‐phenyl group were occupied by bromine atoms, o‐bromination then occurred at the 1‐phenyl group with the aid of the olate oxygen.
Elucidating the resistance repertoire, biofilm production, and phylogenetic characteristics of multidrug‐resistant Escherichia coli isolated from community ponds: A study from West Bengal, India
Authors: Bhattacharyya Debaraj , Banerjee Jaydeep , Habib Md , Thapa Geetanjali , Samanta Indranil , Nanda Pramod Kumar , Dutt Triveni , Sarkar Keka , Bandyopadhyay Samiran
Published: December 2021

This study details about the phenotypic and molecular characteristics of multidrug‐resistant (MDR) Escherichia coli in the fresh community pond water (n = 257) collected from three districts of West Bengal, India. In total, 57 isolates were MDR of which 38 emerged as extended spectrum and 7 as AmpC‐type β‐lactamase producers in phenotypic assay. Among β‐lactamase genes, blaCTXM‐1was predominant (87.71%) followed by blaAmpC (77.2%) and blaTEM‐1 (22.8%). Six MDR strains carried metallo‐β‐lactamase (MBL, blaNDM‐1) gene. Tissue culture plate assay confirmed strong biofilm (SP) production in four MDR and one non‐MDR isolates. In PCR‐based replicon typing (PBRT), multiple plasmids of diverse replicon types (Frep, FIB, I1, FIA, K/B, HI1, and Y) were identified. The enterobacterial repetitive intergenic consensus–polymerase chain reaction (ERIC‐PCR)‐based phylogenetic analysis revealed a high degree of genetic divergence among the MDR isolates. Multiplex PCR‐based phylogrouping categorized 11 isolates as virulent (B2/D/F), which carried blaCTXM‐1 gene and three had blaNDM‐1 gene. Relative transcriptional activity of AcrAB efflux pump was significantly elevated among the SP and MBL producers. The presence of MDR E. coli isolates, particularly those resistant to carbapenem, in pond water used for daily domestic and household work, is a cause of concern as these pathogens may sneak into human food chain causing life‐threatening infections.

Practitioner Points

Multidrug‐resistant biofilm producing E. coli isolated from community pond water.

A few of them were carbapenem‐resistant and belonged to virulent (B2/D) types.

Expression of AcrAB efflux pumps was found significantly elevated among biofilm producers and carbapenem‐resistant population.
Dispersal of aquatic invertebrates by lesser black-backed gulls and white storks within and between inland habitats
Authors: Martín-Vélez Víctor , Sánchez Marta I. , Lovas-Kiss Ádam , Hortas Francisco , Green Andy J.
Published: December 2021

Waterbirds can transport aquatic invertebrates internally, contributing to metapopulation dynamics between aquatic habitats in a terrestrial matrix. However, research into this dispersal process to date has focused on individual field sites or laboratory studies. We investigated the invertebrates dispersed by endozoochory by the lesser black-backed gull Larus fuscus wintering in Andalusia, south-west Spain in 2016–2017, comparing seven sites interconnected by their movements, with different degrees of anthropogenization [three landfills, two saltpan complexes, a natural lake, and a large (370 km2) ricefield area]. In the ricefields, we also compared invertebrates dispersed by gulls with those dispersed by the larger white stork Ciconia ciconia. A total of 642 intact invertebrates and their propagules (mainly plumatellid bryozoans, cladocerans, and other branchiopods) were recorded in excreta (faeces and pellets) from gulls and storks. A greater diversity and abundance of invertebrates were recorded in ricefields, notably 43 individuals of the alien snail Physella acuta. One snail was still alive in a gull pellet 3 weeks after being stored in a fridge. This represents the first record of snail dispersal within waterbird pellets. Viability was also confirmed for the cladoceran Macrothrix rosea recorded in ricefields, and the alien brine shrimp Artemia franciscana recorded mainly in saltpans. In ricefields, gulls and pellets had significantly fewer propagules and fewer taxa per gram of excreta than storks and faeces, respectively. Through their high mobility, gulls and storks can disperse invertebrates between different natural and artificial habitats, and even to landfills. They can promote metapopulation dynamics for native bryozoans and branchiopods, but also the spread of invasive snails and brine shrimp.
Optimization of an autonomous robotic drilling system for the machining of aluminum aerospace alloys
Authors: Pereira Benjamin , Griffiths Christian Andrew , Birch Benjamin , Rees Andrew
Published: December 2021

This paper aims to identify the capability of a highly flexible industrial robot modified with a high-speed machine spindle for drilling of aluminum 6061-T6. With a focus on drilling feed rate, spindle speed, and pecking cycle, the hole surface roughness and exit burr heights were investigated using the Taguchi design methodology. A state of the art condition monitoring system was used to identify the vibrations experienced during drilling operation and to establish which robot pose had increased stiffness, and thus the optimum workspace for drilling. When benchmarked against a CNC machine the results show that the CNC was capable of producing the best surface finish and the lowest burr heights. However, the robot system matched and outperformed the CNC in several experiments and there is much scope for further optimization of the process. By identifying the optimum pose for drilling together with the idealized settings, the proposed drilling system is shown to be far more flexible than a CNC milling machine and when considering the optimized drilling of aerospace aluminum this robotic solution has the potential to drastically improve productivity.
Rickets guidance: part I—diagnostic workup
Authors: Haffner Dieter , Leifheit-Nestler Maren , Grund Andrea , Schnabel Dirk
Published: December 2021

Rickets is a disease of the growing child arising from alterations in calcium and phosphate homeostasis resulting in impaired apoptosis of hypertrophic chondrocytes in the growth plate. Its symptoms depend on the patients’ age, duration of disease, and underlying disorder. Common features include thickened wrists and ankles due to widened metaphyses, growth failure, bone pain, muscle weakness, waddling gait, and leg bowing. Affected infants often show delayed closure of the fontanelles, frontal bossing, and craniotabes. The diagnosis of rickets is based on the presence of these typical clinical symptoms and radiological findings on X-rays of the wrist or knee, showing metaphyseal fraying and widening of growth plates, in conjunction with elevated serum levels of alkaline phosphatase. Nutritional rickets due to vitamin D deficiency and/or dietary calcium deficiency is the most common cause of rickets. Currently, more than 20 acquired or hereditary causes of rickets are known. The latter are due to mutations in genes involved in vitamin D metabolism or action, renal phosphate reabsorption, or synthesis, or degradation of the phosphaturic hormone fibroblast growth factor 23 (FGF23). There is a substantial overlap in the clinical features between the various entities, requiring a thorough workup using biochemical analyses and, if necessary, genetic tests. Part I of this review focuses on the etiology, pathophysiology and clinical findings of rickets followed by the presentation of a diagnostic approach for correct diagnosis. Part II focuses on the management of rickets, including new therapeutic approaches based on recent clinical practice guidelines.
Influence of cold atmospheric plasma on dental implant materials — an in vitro analysis
Authors: Wagner Gunar , Eggers Benedikt , Duddeck Dirk , Kramer Franz-Josef , Bourauel Christoph , Jepsen Søren , Deschner James , Nokhbehsaim Marjan
Published: December 2021

Background and objectives

Alterations in the microenvironment of implant surfaces could influence the cellular crosstalk and adhesion patterns of dental implant materials. Cold plasma has been described to have an influence on cells, tissues, and biomaterials. Hence, the mechanisms of osseointegration may be altered by non-thermal plasma treatment depending on different chemical compositions and surface coatings of the biomaterial. The aim of the present study is to investigate the influence of cold atmospheric plasma (CAP) treatment on implant surfaces and its biological and physicochemical side effects.

Materials and methods

Dental implant discs from titanium and zirconia with different surface modifications were treated with CAP at various durations. Cell behavior and adhesion patterns of human gingival fibroblast (HGF-1) and osteoblast-like cells (MG-63) were examined using scanning electron microscopy and fluorescence microscopy. Surface chemical characterization was analyzed using energy-dispersive X-ray spectroscopy (EDS). Quantitative analysis of cell adhesion, proliferation, and extracellular matrix formation was conducted including real-time PCR.

Results

CAP did not affect the elemental composition of different dental implant materials. Additionally, markers for cell proliferation, extracellular matrix formation, and cell adhesion were differently regulated depending on the application time of CAP treatment in MG-63 cells and gingival fibroblasts.

Conclusions

CAP application is beneficial for dental implant materials to allow for faster proliferation and adhesion of cells from the surrounding tissue on both titanium and zirconia implant surfaces with different surface properties.

Clinical relevance

The healing capacity provided through CAP treatment could enhance osseointegration of dental implants and has the potential to serve as an effective treatment option in periimplantitis therapy.
On density of compactly supported smooth functions in fractional Sobolev spaces
Authors: Dyda Bartłomiej , Kijaczko Michał
Published: December 2021

We describe some sufficient conditions, under which smooth and compactly supported functions are or are not dense in the fractional Sobolev space $$W^{s,p}(\Omega )$$

W

s
,
p

(
Ω
)

for an open, bounded set $$\Omega \subset \mathbb {R}^{d}$$

Ω
⊂

R

d

. The density property is closely related to the lower and upper Assouad codimension of the boundary of $$\Omega$$
Ω
. We also describe explicitly the closure of $$C_{c}^{\infty }(\Omega )$$

C

c

∞

(
Ω
)

in $$W^{s,p}(\Omega )$$

W

s
,
p

(
Ω
)

under some mild assumptions about the geometry of $$\Omega$$
Ω
. Finally, we prove a variant of a fractional order Hardy inequality.
Introducing the Dapivirine Vaginal Ring in Sub-Saharan Africa: What Can We Learn from Oral PrEP?
Authors: Bhavaraju Neeraja , Shears Kathleen , Schwartz Katie , Mullick Saiqa , Jeckonia Patriciah , Murungu Joseph , Persaud Udita , Vij Ashley , Torjesen Kristine
Published: December 2021

Purpose of review

Clinical trials have found that the dapivirine vaginal ring (DVR) is safe to use and effective at reducing women’s risk of acquiring HIV infection. As countries prepare for the introduction of this novel long-acting, woman-controlled prevention method, an examination of key learnings from oral pre-exposure prophylaxis (PrEP) delivery will help programs leverage successful innovations and approaches to support DVR scale-up and expand the method mix for HIV prevention.

Recent findings

Intensive efforts over the past 5 years have yielded lessons on how to facilitate access to oral PrEP; expand service delivery for PrEP; address the knowledge, attitudes, and skills providers need to support PrEP initiation and effective use; develop messaging that builds community and partner support and combats stigma; and understand the cyclical nature of PrEP use.

Evidence from oral PrEP introduction and scale-up can help inform and expedite DVR introduction.
Truncated Local Uniformization of Formal Integrable Differential Forms
Authors: Cano F. , Fernández-Duque M.
Published: December 2021

We prove the existence of Local Uniformization for rational codimension one foliations along rational rank one valuations, in any ambient dimension. This result is consequence of the Truncated Local Uniformization of integrable formal differential 1-forms, that we also state and prove in the paper. Thanks to the truncated approach, we perform a classical inductive procedure, based both in the control of the Newton Polygon and in the possibility of avoiding accumulations of values, given by the existence of suitable Tschirnhausen transformations.
Psychosexual Morbidity in Women With Ovarian Cancer: Evaluation by Germline BRCA Gene Mutational Status
Authors: Logue Chloe A. , Pugh Julia , Foden Philip , Mahmood Reem D. , Morgan Robert D. , Mitchell Claire , Hasan Jurjees , Clamp Andrew R. , Jayson Gordon C.
Published: December 2021

Introduction

Up to 75% of women with ovarian cancer experience psychosexual morbidity and approximately 15–20% of women with ovarian cancer have a germline BRCA1/2 mutation (gBRCAm). However, psychosexual morbidity remains unexplored in women with gBRCAm ovarian cancer.

Aim

Given their younger age, genetic diagnosis, breast cancer risk, and increased prevalence of surgically-induced menopause, we aim to assess whether women with gBRCAm ovarian cancer experience distinct psychosexual morbidity.

Methods

Psychosexual morbidity was investigated in 2 cohorts of women with ovarian cancer: women with gBRCAm ovarian cancer vs women with gBRCA wildtype (gBRCAwt) ovarian cancer. Between August 2019 and March 2020, women with high-grade serous carcinoma of the ovary, Fallopian tube or primary peritoneum were approached in clinic or telephoned and invited to take part. Exclusion criteria included: women with alternative histology; women admitted from clinic; and women who lacked capacity to independently complete the questionnaire. The Female Sexual Function Index (FSFI) and background information were collected at a single time-point per patient. Scores below 26.55 were interpreted to suggest psychosexual dysfunction.

Main Outcome Measure

Responses including total and domain FSFI scores, self-reported psychosexual problems and interest in psychosexual support were compared.

Results

Of 103 women approached, 53% returned questionnaires. In this exploratory analysis, women with gBRCAm ovarian cancer were significantly younger (51–60 years vs 61–70 years, gBRCAwt, P = .010). There was a trend towards increased prevalence of surgical menopause (57% vs 27%, P = .097) and breast surgery (53% vs 22%, P = .132, gBRCAm vs gBRCAwt, respectively). Women with gBRCAm ovarian cancer scored higher in the FSFI questionnaire, particularly women under 60 years (15.1 vs 2.7, P = .070), approaching significance. Women with gBRCAm ovarian cancer expressed more interest for face-to-face services (P = .018), especially psychosexual therapy (65% vs 30%) and more often felt the service was insufficient, approaching significance (71% vs 44%, gBRCAm vs gBRCAwt, respectively, P = .076).

Conclusion

Women with gBRCAm ovarian cancer are younger, express more interest for specialist psychosexual support and potentially different psychosexual problems, warranting further exploration.
Sources of exposure identified through structured interviews of healthcare workers who test positive for severe acute respiratory coronavirus virus 2 (SARS-CoV-2): A prospective analysis at two teaching hospitals
Authors: Rhee Chanu , Baker Meghan A. , Tucker Robert , Griesbach Diane , McDonald Dinah , Williams Sarah A. , Fiumara Karen , Resnick Andrew , Klompas Michael ,   for the CDC Prevention Epicenters Program
Published: December 2021

We interviewed 1,208 healthcare workers with positive SARS-CoV-2 tests between October 2020 and June 2021 to determine likely exposure sources. Overall, 689 (57.0%) had community exposures (479 from household members), 76 (6.3%) had hospital exposures (64 from other employees including 49 despite masking), 11 (0.9%) had community and hospital exposures, and 432 (35.8%) had no identifiable source of exposure.
Gennaeocrinus tariatensis, a new Emsian (Devonian) monobathrid crinoid from the Tarvagatay Terrane of Mongolia
Authors: Waters Johnny A. , Ausich William I.
Published: December 2021

Gennaeocrinus tariatensis new species is an Emsian (Devonian) monobathrid crinoid described from the Tarvagatay Terrane of Mongolia and part of the Central Asian Orogenic Belt. The Tarvagatay Terrane is an arc terrane that accreted to the southern margin of the Siberian Craton. Gennaeocrinus tariatensis was collected from the Emsian Tariat Formation, a terrigenous sequence of conglomerates, sandstones, and siltstones. Associated faunas include brachiopods, molluscs, and rare tabulate corals. Although Gennaeocrinus is well known from the Emsian–Givetian of North America, this is the first occurrence of the genus outside Laurussia. Mongolia is a large country with many terranes having varied paleogeographic, sedimentological, and tectonic histories; but reports of Paleozoic echinoderms are rare. The crinoid occurrence from the Tariat Formation is from the same age as previously described Emsian crinoids from the Chuluum Formation but differs significantly in sedimentology, paleogeography, and paleolatitude.

UUID: http://zoobank.org/d87cb083-4360-41e5-ac90-1b8ef625a31d
TROPISMS – A PERSONAL HISTORY OF THE GENESIS OF A COMPOSITION, STRING QUARTET NO. 5, DANCERS ON A PLANE
Authors: Volans Kevin
Published: December 2021

This article considers the nature of the relationship between composers and musicologists and explores the aesthetic roots and ideas of my 5th String Quartet, Dancers on a Plane, which has recently been the subject of a musicological study.
Numerosities are not ersatz numbers
Authors: Dutilh Novaes Catarina , dos Santos César Frederico
Published: December 2021

In describing numerosity as “a kind of ersatz number,” Clarke and Beck fail to consider a familiar and compelling definition of numerosity, which conceptualizes numerosity as the cognitive counterpart of the mathematical concept of cardinality; numerosity is the magnitude, whereas number is a scale through which numerosity/cardinality is measured. We argue that these distinctions should be considered.