bluuebunny/crossref_metadata_2025 huggingface dataset:
Computational Multi‐Scale Stability Analysis of Periodic Electroactive Polymer Composites at Finite Strains
Authors: Polukhov Elten , Vallicotti Daniel , Keip Marc‐André
Published: March 2018

This work is dedicated to multi‐scale stability analysis, especially macroscopic and microscopic stability analysis of periodic electroactive polymer (EAP) composites with embedded fibers. Computational homogenization is considered to determine the response of materials at macro‐scale depending on the selected representative volume element (RVE) at micro‐scale [4, 5]. The quasi‐incompressibility condition is considered by implementing a four‐field variational formulation on the RVE, see [7]. Based on the works [1–3, 6, 8] the macroscopic instabilities are determined by the loss of strong ellipticity of homogenized moduli. On the other hand, the bifurcation type microscopic instabilities are treated exploiting the Bloch‐Floquet wave analysis in context of finite element discretization, which allows to detect the changed critical size of periodicity of the microstructure and critical macroscopic loading points. Finally, representative numerical examples are given which demonstrate the onset of instability surfaces, the stable macroscopic loading ranges, and further a periodic buckling mode at a microscopic instability point is presented. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Derivation of an n‐layered composite sphere model for thermo‐chemo‐mechanical effective properties
Authors: Dammann Christian , Mahnken Rolf , Lenz Peter
Published: March 2018

Our work presents extensions of multi layered composite sphere models known from the literature to temperature‐dependent elastic effects accompanied by curing. In particular, volumetric effective properties are obtained by homogenization for a representative unit cell (micro‐RVE) on the heterogeneous microscale for thermo‐chemo‐mechanical coupling within linear elasticity. To this end, an analytical solution for an n‐layered composite sphere model is derived. In a numerical study for a (3)‐phase matrix it is demonstrated that the effective elastic and thermal properties lie within Voigt and Reuss bounds, whilst for the chemical part of the model an analogous result is obtained for the effective strains. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Homogenization of periodic micro‐structures with FFT‐based higher order schemes
Authors: Dietrich Felix , Merkert Dennis
Published: March 2018

A matrix‐free homogenization method making use of the fast Fourier transform (FFT) to work on structured grids was introduced by Moulinec and Suquet in 1994. Due to its simplicity and computational advantages, this so‐called Basic Scheme has provided the basis for many works in the past two decades. An extension presented by Tran, Monchiet and Bonnet allows for the quasi‐static equations of linear elasticity to include effects from higher‐order derivatives by expanding the strain and the displacement as asymptotic series. To compute the solution hierarchically, we derive generalized Lippmann Schwinger‐type equations. Furthermore, we show how existing algorithms have to be adapted for these problems. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐Scale Simulation of a Disc With a Crack by X‐FEM and Cell Model
Authors: Donhauser Michael , Schmerbauch Mario , Matzenmiller Anton
Published: March 2018

The two‐scale simulation of a linear‐elastic orthotropic disc with a central crack under mode‐I loading may be used to verify the extended finite element method implementation of orthotropic enrichment functions into finite element codes such as FEAP. The stress distribution on the finer scale is simultaneously resolved by the high fidelity generalized method of cells called at each integration point of the macro elements. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient Simulation of Short Fibre Reinforced Composites
Authors: Springer Rolf , Meyer Arnd
Published: March 2018

In this paper we present a way how short fibre reinforced composites, produced by injection moulding, can be simulated in a linear thermoelastic setting, with an stationary heat equation. The main problem is the unknown stochastic fibre orientation. The only information known about this orientation field are the first moments of its distribution. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stochastic Modeling of Turbulent Scalar Transport at Very High Schmidt Numbers
Authors: Klein Marten , Schmidt Heiko
Published: March 2018

A stochastic modeling approach, the so‐called One‐Dimensional Turbulence (ODT), is used to study passive scalar transport in incompressible, fully‐developed, turbulent channel flows up to very high Schmidt numbers Sc = ν/Γ ∼ 104 (kinematic viscosity ν, scalar diffusivity Γ). Good agreement is obtained between ODT and Direct Numerical Simulation (DNS) results with respect to the mean, the fluctuation statistics, and the dimensionless mass transfer coefficient K+. ODT yields the mass transfer coefficient to become independent of the Reynolds number at high Schmidt numbers, which is similar to reference laboratory measurements and DNS. The present ODT results exhibit the power law K+ ∝ Sc−0.65 with a scaling exponent that is only slightly larger than in the reference laboratory measurements and DNS. The results obtained suggests that ODT can be a versatile tool for turbulent transport modeling in a wide range of physical parameters. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of ODT to constant volume autoignition problems
Authors: Medina Méndez Juan A. , Schmidt Heiko
Published: March 2018

The One‐Dimensional Turbulence (ODT) model is applied to a constant volume configuration by means of a periodic, one‐dimensional domain subject to randomized ensemble members with initial inhomogeneous temperature fields and homogeneous mass fraction profiles. The multidimensional turbulent interactions in the flow are modeled by the separate implementation of turbulent advection and the diffusion‐reaction processes, neglecting the mean advection of the system. On one hand, turbulent advection is modeled by means of the eddy events defined within the framework of ODT; on the other hand, the diffusion‐reaction system is solved by means of the Zero‐Mach limit conservation equations discretized with a 1D Finite Volume Method (FVM). The treatment is specialized in this work to constant volume systems. Due to the inherent stiffness of the diffusion‐reaction system, an operator splitting approach is also included in the formulation. Results for n‐Heptane chemistry comprising the temporal evolution of the heat release rate, pressure and normalized density‐weighted displacement speed are shown and compared to DNS results from Yoo et al. [Combust. Flame 158 (2011) 1727‐1741], in terms of individual ensemble members and mean ensemble behavior. The results show that it is possible to obtain reasonably good results in comparison to the DNS if an appropriate set of initial conditions is used. Furthermore, it is shown that the model uncertainty is negligible in comparison to the ensemble standard deviation introduced by randomized initial conditions. Overall, this work introduces the framework for constant volume autoignition in ODT and shows its efficiency for complex chemistry simulations. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laws of the wall for velocity and temperature in supersonic turbulent boundary layers
Authors: Vigdorovich Igor
Published: March 2018

Scaling laws for velocity and temperature profiles in the near‐wall region of sub‐ and supersonic turbulent boundary layers have been developed, which allow us to represent velocity and temperature profiles in compressible gas stream in terms of those in an incompressible boundary layer. They are obtained as asymptotic expansions of the solutions to the Reynolds equations in a small parameter — the Mach number based on the friction velocity and gas enthalpy on the wall. The leading term of the expansion for velocity corresponds to known Van Driest's formula. However, the obtained solution contains additional terms of order unity, which explains the contradiction between Van Driest's formula and experimental data. The law of the wall for temperature, which has been formulated for the first time, has an analogous structure. Besides the von Kármán constant and the turbulent Prandtl number in the logarithmic region, known for incompressible flow, the obtained relations contain three new universal constants, which do not depend on gas molecular properties and the specific heat ratio. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Modelling the filling process of lithium‐ion batteries
Authors: Neumann Tim , Boettcher Konrad , Ehrhard Peter
Published: March 2018

Lithium‐ion batteries are composed of several single cells, each consisting of conductive, impermeable electrodes made of aluminum and copper. Both are coated with a thin, porous layer on both sides (collectors) and a thin, non‐conductive and permeable layer is separating them. As the layers are stacked, the liquid enters the battery at all front edges, while the gas is trapped inside. To estimate the filling process of these batteries with the viscous suspensions containing the electrolyte, a model for the flow of a well‐wetting liquid displacing a gas in a single cell is established. This can be modeled as a stack of three porous layers with heterogeneous characteristics (cf. figure 2). The porous structure of the electrode coatings is approximated as a packed bed of spheres. Considering the small ratio of layer thickness to particle diameter, the influence of the wall effect onto the relevant forces has to be taken into account. These models according to the hydrodynamics of this multi‐phase flow are implemented into the commercial CFD‐software Ansys CFX. Derived from the numerical results, a 1D description is developed to specify the whole filling process. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Application of the Stochastic Field Method to two phase flow
Authors: Raquet Martin , Class Andreas , Edelbauer Wilfried
Published: March 2018

The Stochastic Field Method was introduced in the field of combustion and represents a Eulerian Monte‐Carlo technique. It was first transfered to the field of multiphase flow in [1] facing a problem in nuclear technology. Within this work it is applied to cavitating flows in the automotive sector. Both phases, the continuous and the dispersed phase, are observed using a Eulerian perspective which fits the architecture of CFD solvers resulting in efficient computations. Instead of solving the behaviour of individual bubbles, as in Lagrangian Particle Methods, variations of volume fractions of the dispersed phase in each computational mesh cell are considered. A stochastic term is introduced into the transport equations for the volume fractions of the dispersed phase via a Wiener process. Thus sampling over several time steps provides the probability density function of volume fraction in each mesh cell. The implementation is carried out by compiling user‐functions to a commercial CFD code. A test case representing an injection system in an automotive application is presented. Moreover strategies to implement the effect of coalescence are shown. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Linear forced sloshing for a baffled rectangular fuel tank
Authors: Buck Fabian , Hetzler Hartmut , Fruend Eckhard , Oexl Stefan
Published: March 2018

Sloshing in a fuel tank of a commercial vehicle, which is subdivided by a perforated plate as baffle, is investigated to predict occuring forces. Using linear potential theory and a two‐dimensional modal description, the eigenmodes and eigenfrequencies are determined for the baffled tank and compared to experimental results. Damping due to viscous boundary layers and the pressure drop at the baffle is examined and discussed with regard to experimental findings. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experimental investigation of the effect of aircraft trailing vortices on roofs
Authors: Uhl Anna , Braun Sebastian , Hille Sebastian , Hörnschemeyer Ralf , Stumpf Eike
Published: March 2018

Roofs of buildings in the vicinity of airports can be damaged by trailing vortices of aircraft during take‐off and landing. Preliminary experimental investigations have been conducted in a water towing tank in order to examine a discrepancy between damage probability assumptions and actual roof damage frequency. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparison of parametric and non‐parametric methods for bladed disks with random geometric mistuning
Authors: Koebele Maxime , Proppe Carsten
Published: March 2018

This paper presents different strategies to quantify the influence of random geometric mistuning on the dynamic behavior of bladed disk. These strategies are compared for different correlation lengths of the random field describing the blade geometry. The results allow to determine the kind of random geometric mistuning for which these strategies are appropriate. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optimal Expansion Planning for an Electric Distribution Network with the NLP Solver WORHP
Authors: Berger Arne , Jung Francesca , Echim Mitja , Büskens Christof , Schollmeyer Michael
Published: March 2018

This paper shows how an electrical distribution network can be modeled as constraints of a continuous nonlinear optimization problem. The objective is to minimize the deviation from a given nominal voltage. We explain how this setup can be used to optimize wire diameters within the network. Thus we find the optimal expansion of the network by identifying wires which should be enforced. The results are shown by applying the functionality to a real world example. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Localized and efficient estimators for obstacle problems in the context of standard residual estimators
Authors: Walloth Mirjam
Published: March 2018

In order to localize the estimator contributions with respect to the active set of constraints special error measures and residual‐type estimators have been derived for different variational inequalities [2–4]. Considering the classical obstacle problem, we summarize the basic ideas and draw a relation to estimators for linear elliptic problems without constraints. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Implementing an image based control algorithm for an optomechanical image derotator
Authors: Altmann Bettina , Pape Christian , Reithmeier Eduard
Published: March 2018

In this paper an image‐based control for an optomechanical image derotator is implemented. A derotator is an optical system to support measurements on rotating components by tracking their rotational movement. As a consequence, the position and rotational velocity of the measurement object has to be known continuously. In general this would be accomplished by measuring these variables using a rotary encoder. However, not all measuring objects are equipped for this task. As a solution universally applicable to a wide range of measuring objects, an image‐based approach is developed in the scope of this work. The object is captured with a high‐speed camera to determine its position and velocity by image processing algorithms. To proof the applicability of this concept, a controller using the data acquired with the camera and a controller using data of the rotary encoder are compared. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Approximation and implementation of transformation based feedback laws for distributed parameter systems
Authors: Ecklebe Stefan , Riesmeier Marcus , Woittennek Frank
Published: March 2018

A novel approach to the efficient numerical approximation and implementation of transformation based state feedback originating from backstepping or flatness based approaches is applied to a flatness based feedback law for the so called heavy rope system. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Efficient and accurate two‐scale simulation of non‐linear heterogeneous microstructures
Authors: Kochmann Julian , Wulfinghoff Stephan , Svendsen Bob , Reese Stefanie
Published: March 2018

This work is concerned with the development of an efficient two‐scale numerical scheme for the prediction of the local and effective mechanical response of heterogeneous materials with non‐linear constitutive behavior. In order to ensure both, accurate micromechanical fields and feasible overall CPU‐times, an efficient but rather simple solution scheme is proposed. Its capabilities are demonstrated using the FE‐FFT method [2,3] for the solution of simple two‐scale problems. As an example, two‐dimensional polycrystalline microstructures with an elasto‐viscoplastic constitutive law are considered. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Active Impedance Matching in Slender Continua via a Special PID Controller
Authors: Krumm Ludwig , Kreuzer Edwin
Published: March 2018

The concept of impedance matching is well known in electrical engineering and can be applied in mechanical engineering as well. Slender systems, which have a relatively low stiffness and should not be treated as a rigid body are typical candidates for the application of impedance matching.

Impedance matching imposes a special boundary condition. In general, at the boundary of a slender mechanical system, waves are partially reflected. The goal of impedance matching is to minimize those wave reflections and to transmit the wave motion to the vicinity. In this paper, it is shown that the impedance matching approach has a great potential of damping vibrations and that a simple PID controller can be used to implement an active version. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Screw Theory – A forgotten Tool in Multibody Dynamics
Authors: Müller Andreas
Published: March 2018

Mechanism theory, synthesis and control of robots, rigid body dynamics, geometrically exact formulations of the kinematics of continua, structure preserving numerical integration methods, and in part geometric mechanics – they all have a common denominator, namely the theory of screws, for which Lie group theory forms the mathematical foundation. This paper is an attempt to provide a short survey identifying several scientific areas where screw theory is already (sometimes implicitly) used and such where its systematic application could lead to new formulations and computational algorithms. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On quadratic stage costs for mobile robots in model predictive control
Authors: Müller Matthias A. , Worthmann Karl
Published: March 2018

We consider nonholonomic mobile robots. Since the system is finite time controllable, it is stabilizable by a receding horizon control scheme with purely quadratic stage costs if an infinite optimization horizon is employed. However, due to the so called short‐sightedness of model predictive control, these stability properties are not preserved if the control problem is only optimized on a truncated and, thus, finite prediction horizon — even if an arbitrarily large terminal weight is added. Hence, it is necessary to either incorporate structurally different terminal costs or use non‐quadratic stage costs to appropriately penalize the deviation from the desired set point. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An Efficient Thermo‐Kinematic (ETK) Model for Long‐Time Simulation of High Speed Railway Brake Dynamics
Authors: Srisupattarawanit T. , Ostermeyer G.‐P. , Schiefer F.
Published: March 2018

High speed railway brakes transfer a large amount of kinetic energy into heat during the brake operation. Due to its design one major problem is tapered wear, which could significantly reduce brake performance and safety as well as increase aftermarket costs. Modeling and simulation of these brake systems is rather complicated with respect to the coupled multiphysics, multiscaled phenomena, friction and wear, especially on long time scale. Here, we present the so‐called Efficient Thermo‐Kinematic (ETK) model, which include the complexities of the multiphysics of the brake process in the efficient way. Using this model, we are able to proceed the simulation of the brake dynamics in long‐time scale. The partial differential equations are derived based on the coupled manner. The simulation with ETK model shows reasonable results with very fast computational time. The ratio of computing time to real time can reach 1:2000 (with a standard personal computer). Thus, investigations on tapered wear can be performed not only in one brake operation but in many times of brake operations. The simulation results will support the development process of railway brakes in order to mitigate tapered wear of the brake pads. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Constitutive model error and uncertainty quantification
Authors: Franck Isabell M. , Koutsourelakis P.S.
Published: March 2018

This paper proposes a novel Bayesian strategy for high‐dimensional inverse problems in the context of elastostatics. Apart from parametric uncertainties, model inadequacies and, particularly, constitutive model errors, are also addressed. This is especially important in biomedical settings when the inferred material properties will be used to make decisions/diagnoses. Traditional approaches use an additional regression model (e.g., Gaussian process), added to the model output or within a submodel to account, for an underlying model error. This can violate physical constraints and becomes impractical in high dimensions.

In this work we unfold conservation and constitutive laws to estimate model discrepancies. In addition, efficient Bayesian strategies are employed. In elastography, the accurate identification of the unknown mechanical properties of a tissue as well as the associated uncertainty, can greatly assist noninvasive, medical diagnosis. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stochastic upscaling of random microstructures
Authors: Rosić Bojana , Sarfaraz Muhammad Sadiq , Matthies Hermann G. , Ibrahimbegović Adnan
Published: March 2018

In this work we present an upscaling technique for multi‐scale computations based on random microstructures modelled as realisations of lognormally distributed random fields, or described by randomly distributed inclusions in a homogeneous matrix. Their corresponding coarse‐scale model parameters are considered as uncertain, and are approximated by random variables, the distributions of which are obtained via polynomial chaos based Bayesian procedures in which the fine‐scale energy is used as an observation. (© 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The advanced glycation end‐product Nϵ‐carboxymethyllysine promotes progression of pancreatic cancer: implications for diabetes‐associated risk and its prevention
Authors: Menini Stefano , Iacobini Carla , de Latouliere Luisa , Manni Isabella , Ionta Vittoria , Blasetti Fantauzzi Claudia , Pesce Carlo , Cappello Paola , Novelli Francesco , Piaggio Giulia , Pugliese Giuseppe
Published: March 2018

Diabetes is an established risk factor for pancreatic cancer (PaC), together with obesity, a Western diet, and tobacco smoking. The common mechanistic link might be the accumulation of advanced glycation end‐products (AGEs), which characterizes all of the above disease conditions and unhealthy habits. Surprisingly, however, the role of AGEs in PaC has not been examined yet, despite the evidence of a tumour‐promoting role of receptor for advanced glycation end‐products (RAGE), the receptor for AGEs. Here, we tested the hypothesis that AGEs promote PaC through RAGE activation. To this end, we investigated the effects of the AGE Nϵ‐carboxymethyllysine (CML) in human pancreatic ductal adenocarcinoma (PDA) cell lines and in a mouse model of Kras‐driven PaC interbred with a bioluminescent model of proliferation. Tumour growth was monitored in vivo by bioluminescence imaging and confirmed by histology. CML promoted PDA cell growth and RAGE expression, in a concentration‐dependent and time‐dependent manner, and activated downstream tumourigenic signalling pathways. These effects were counteracted by RAGE antagonist peptide (RAP). Exogenous AGE administration to PaC‐prone mice induced RAGE upregulation in pancreatic intraepithelial neoplasias (PanINs) and markedly accelerated progression to invasive PaC. At 11 weeks of age (6 weeks of CML treatment), PaC was observed in eight of 11 (72.7%) CML‐treated versus one of 11 (9.1%) vehicle‐treated [control (Ctr)] mice. RAP delayed PanIN development in Ctr mice but failed to prevent PaC promotion in CML‐treated mice, probably because of competition with soluble RAGE for binding to AGEs and/or compensatory upregulation of the RAGE homologue CD166/ activated leukocyte cell adhesion molecule, which also favoured tumour spread. These findings indicate that AGEs modulate the development and progression of PaC through receptor‐mediated mechanisms, and might be responsible for the additional risk conferred by diabetes and other conditions characterized by increased AGE accumulation. Finally, our data suggest that an AGE reduction strategy, instead of RAGE inhibition, might be suitable for the risk management and prevention of PaC. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Polydrug epidemiology: Benzodiazepine prescribing and the drug overdose epidemic in the United States
Authors: Zoorob Michael James
Published: March 2018

Background

Although polydrug incidents comprise a substantial proportion of overdose deaths, scholarly and popular focus has centered on prescription opiates. This study examines the role of benzodiazepine and opioid prescriptions on overdose—both individually and synergistically—using data from Medicare Part D, a source of prescription drug claims for about 35 million Americans.

Methods

Prescribing data from the Medicare Part D Public Use Files for 2013, 2014, and 2015 (approximately 3.5 billion prescription drug claims) are geolocated using the prescriber's national provider identifier to calculate the proportion of claims for opioids and benzodiazepines in each county. These rates are matched with overdose data and controls to compile an analytic dataset of 9105 county‐years. Multinomial logistic regression is used to estimate the probability that a county experiences higher rates of overdose fatalities.

Results

A 1% increase in the benzodiazepine proportion of claims is associated with 1.2 odds of high, versus low, overdose (P < .1) and 1.4 odds of very high overdose (P < .05). Moreover, there was a substantial interaction between opioids and benzodiazepines (P < .001). A county with 6% benzodiazepine prescriptions and 12% opioid prescriptions has a .58 predicted probability of very high overdose, significantly higher (P < .001) than the .33 probability for a county with 12% opioid prescriptions but 3% benzodiazepine prescriptions.

Conclusion

These findings shed light on the polydrug epidemiology of the overdose epidemic. Overdose deaths are highest where elevated opioid and benzodiazepine claims coexist. Overdose levels may reflect polydrug use and misuse, requiring clinical and policy responses beyond reducing opioid prescriptions.
Functional dendrimer–gold nanoparticle hybrids for biomedical applications
Authors: Li Xiaojie , Kono Kenji
Published: March 2018

Dendrimers are a class of nano‐sized synthetic polymers with a well‐defined composition and regularly branched tree‐like structure produced by stepwise growth. The uniform size, globular shape and tunable surface chemistry make dendrimers versatile nanoscaffolds to encapsulate or stabilize various inorganic (metal, metal oxide, semiconductor) nanoparticles. In the past decade, research interest in dendrimer–inorganic nanoparticle hybrids has evolved from the development of interesting properties to the exploitation of advanced and useful functions. In particular, because gold nanoparticles with controlled morphology and optical properties have been demonstrated to be promising and versatile candidates for a diverse field of biomedical applications including sensing, in vitro and in vivo imaging, drug delivery, diagnostics and therapies, dendrimer–gold nanoparticle hybrids with biocompatibility have recently been intensively investigated for promising biomedical applications due to their controllable structures and dimensions, as well as their desirable internal and/or external functionalities. In this review, we discuss the recent progress regarding the development of functional dendrimer–gold nanoparticle hybrids for biomedical applications. The strategies for the fabrication of various structures of dendrimer–gold nanoparticle hybrids will first be summarized, followed by their biomedical applications in drug and gene delivery, photothermal therapy and combined therapies. © 2018 Society of Chemical Industry
Anionic ring‐opening polymerization of N‐glycidylphthalimide: Combination of phosphazene base and activated monomer mechanism
Authors: Rassou Somasoudrame , Illy Nicolas , Tezgel Ozgul , Guégan Philippe
Published: March 2018

Anionic ring‐opening polymerization of glycidyl phthalimide, initiated with alcohol–phosphazene base systems and based on monomer activation with a Lewis acid (iBu3Al), has been studied. No propagation occurred for initiator: iBu3Al ratios less or equal to 1:3. For larger Lewis acid amounts, the first anionic ring‐opening polymerizations of glycidyl phthalimide were observed. Polymers were carefully characterized by NMR, MALDI‐TOF mass spectrometry, and size exclusion chromatography and particular attention was given to the detection of eventual transfer or side‐reactions. However, polymer precipitation and transfer reaction to aluminum derivative were detrimental to monomer conversion, polymerization control, and limited polymer chain molar masses. The influence of reaction temperature and solvent on polymer precipitation and transfer reactions was studied and reaction conditions have been optimized leading to afford end‐capped poly(glycidyl phthalimide) with narrow molar mass distributions. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1091–1099
Sustainable, fire‐resistant phthalonitrile‐based glass fiber composites
Authors: Laskoski Matthew , Shepherd Arica R. , Mahzabeen Wadia , Clarke Jadah S. , Keller Teddy M. , Sorathia Usman
Published: March 2018

The sustainable resveratrol‐based phthalonitrile was used in the preparation of E‐glass fiber‐reinforced phthalonitrile composite panels fabricated by hot pressed prepreg consolidation with bis[4‐(3‐aminophenoxy)phenyl]sulfone (m‐BAPS) as the curing additive. This amorphous monomer exhibited excellent viscosities at temperatures below 200 °C, which is applicable to standard processing conditions. Rheometric measurements were used to evaluate the cure of the composite as a function of the postcure conditions. The composite retains >95% of its room temperature storage modulus up to 450 °C based on these postcuring parameters. More importantly, flammability performance of the composite—which was determined in terms of ignitability, heat release, and mass loss rate—excels over other state‐of‐the‐art polymer/glass composites. Even under the most extreme heat fluxes (e.g., 100 kW⋅m−2), the composite performs exceptionally well suggesting that resveratrol‐based phthalonitrile composites can be used in fire‐resistant applications. Published 2018.† J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1128–1132
D‐π‐a‐type oxime sulfonate photoacid generators for cationic polymerization under UV–visible LED irradiation
Authors: Jin Ming , Zhou Ruchun , Yu Man , Pan Haiyan , Wan Decheng
Published: March 2018

Four D‐π‐A‐type nonionic oxime sulfonate photoacid generators (PAGs) have been designed and synthesized for use in light‐emitting diode (LED) excitable cationic photoinitiators, in which N,N‐diphenylamino was used as electron donor with trifluoroacetophenone‐based oxime sulfonates (trifluoromethanoesulfonate and p‐toluenesulfonate) as electron acceptor and substituted fluorene and biphenyl groups as the π‐conjugated systems. PAG‐Ben‐Tol (with biphenyl and p‐toluenesulfonate) and PAG‐Flu‐Tol (with fluorene and p‐toluenesulfonate) showed high quantum yields of photoacid generation (0.33–0.50) and very good thermal stability (over 250 °C). The absorbance spectra of these PAGs were consistent with the emission spectra of commercially gained UV–visible LED light sources. The potential of these PAGs for cationic photoinitiators was tested in two cationic monomer systems. These PAGs needed low light intensity and low concentration for photopolymerization with high conversions of monomer, for example, over 80%, gained at 3.0 mW cm−2 from 365 to 470 nm LEDs. The photochemical mechanisms of these PAGs are comprehensively investigated and discussed in detail. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1146–1154
Ozone disinfection of home nebulizers effectively kills common cystic fibrosis bacterial pathogens
Authors: Towle Dana , Baker Vanisha , Schramm Craig , O'Brien Matthew , Collins Melanie S. , Feinn Richard , Murray Thomas S.
Published: March 2018

Objective

The Cystic Fibrosis Foundation (CFF) recommends routine nebulizer disinfection for patients but compliance is challenging due to the heavy burden of home care. SoClean® is a user friendly ozone based home disinfection device currently for home respiratory equipment. The objective of this study was to determine whether SoClean® has potential as a disinfection device for families with CF by killing CF associated bacteria without altering nebulizer output.

Hypothesis

Ozone based disinfection effectively kills bacterial pathogens inoculated to home nebulizer equipment without gross changes in nebulizer function.

Study Design

Common bacterial pathogens associated with CF were inoculated onto the PariLC® jet nebulizer and bacterial recovery compared with or without varied ozone exposure. In separate experiments, nebulizer output was estimated after repeated ozone exposure by weighing the nebulizer.

Results

Ozone disinfection was time dependent with a 5 min infusion time and 120 min dwell time effectively killing >99.99% bacteria tested including Pseudomonas aeruginosa and Staphylococcus aureus. Over 250 h of repeat ozone exposure did not alter nebulizer output. This suggests SoClean® has potential as a user‐friendly disinfection technique for home respiratory equipment.
MiR‐206 inhibits proliferation and migration of prostate cancer cells by targeting CXCL11
Authors: Wang Yao , Xu Haitao , Si Lihui , Li Qiuju , Zhu Xiujie , Yu Tong , Gang Xiaokun
Published: March 2018

Background

Our study was aimed at detecting the expression levels of miR‐206 in prostate cancer (PCa) tissues and PCa cell lines, and exploring the potential functions of miR‐206 by targeting chemokine ligand 11 (CXCL11).

Methods

RT‐qPCR was applied to detect the expressions of miR‐206 and CXCL11 in PCa tissues and in PCa cell lines. Expression of the CXCL11 protein was detected using Western blot. After manipulating the expression of miR‐206 and CXCL11 in PC‐3 and DU‐145 cells, the changes of cell proliferation and cell cycle were observed through cell counting kit‐8 (CCK‐8) and flow cytometry. Wound healing and transwell assay were conducted for cell migration and invasion examination in vitro. The luciferase reporter assay was applied to validate the association between miR‐206 and CXCL11.

Results

MiR‐206 was significantly under‐expressed in PCa tissues and in PCa cell lines. Up‐regulation of miR‐206 could inhibit proliferation, migration, invasion and induced G1/G0 arrest of PCa cells, and vice versa. MiR‐206 bound to the 3′‐UTR of CXCL11 and significantly repressed the luciferase activity. Overexpression of miR‐206 decreased the expression level of CXCL11 significantly. CXCL11 mRNA and protein levels were significantly decreased in PCa cells. Downregulation of CXCL11 presented tumor‐suppressing effects on PCa cells as miR‐206 mimics did. And co‐transfection miR‐206 attenuated the tumor‐promoting effects induced by CXCL11 overexpression.

Conclusion

Our current finding demonstrated that miR‐206 negatively regulated PCa cell proliferation and migration, and arrested cell cycle by targeting CXCL11 as a tumor suppressor in prostate cancer.
Risk assessment of class 3 (PG II & III) hazardous materials in transportation
Authors: Quddus Noor , Yu Mengxi , Tamim Nafiz , Rahmani Samina , Mannan M. Sam
Published: March 2018

Risks associated with transportation of Class 3 packing group II & III hazardous materials in transport by motor carriers were investigated. Incident data of transportation of Class 3 materials was collected from the Pipeline and Hazardous Materials Safety Administration (PHMSA) database for a period of 10 years (2005–2014). The collected incident data was screened later for small quantities (≤ 8 gallons) and for single component (32,455 incidents). Root causes of the incidents (31,307 incidents) were categorized according to different transportation phases and corresponding frequencies were determined. Using the available consequence data (fatality/injury, financial damage, and quantity released) incident pyramids were prepared and later risk matrices were developed for fatality/injury, financial damage, and quantity released. Analysis found the risk of Class 3 (PG II & III) material in transportation a low consequence‐high frequency phenomenon and also revealed some key issues such as almost two‐third of the total incidents occurred during “unloading” phase of the transportation. Procedural deviation and human error were found as the two most frequently cited categories, and there was no incident resulting in fatality in these ten years. © 2018 American Institute of Chemical Engineers Process Process Saf Prog 37:376–381, 2018
Spray droplet size and carrier volume effect on dicamba and glufosinate efficacy
Authors: Butts Thomas R , Samples Chase A , Franca Lucas X , Dodds Darrin M , Reynolds Daniel B , Adams Jason W , Zollinger Richard K , Howatt Kirk A , Fritz Bradley K , Clint Hoffmann Wesley , Kruger Greg R
Published: March 2018

BACKGROUND

Pesticide applications using a specific droplet size and carrier volume could maximize herbicide efficacy while mitigating particle drift in a precise and efficient manner. The objectives of this study were to investigate the influence of spray droplet size and carrier volume on dicamba and glufosinate efficacy, and to determine the plausibility of droplet‐size based site‐specific weed management strategies.

RESULTS

Generally, across herbicides and carrier volumes, as droplet size increased, weed control decreased. Increased carrier volume (187 L ha−1) buffered this droplet size effect, thus greater droplet sizes could be used to mitigate drift potential while maintaining sufficient levels of weed control. To mitigate drift potential and achieve satisfactory weed control (≥ 90% of maximum observed control), a 900 µm (Ultra Coarse) droplet size paired with 187 L ha−1 carrier volume is recommended for dicamba applications and a 605 µm (Extremely Coarse) droplet size across carrier volumes is recommended for glufosinate applications. Although general droplet size recommendations were created, optimum droplet sizes for weed control varied significantly across site‐years.

CONCLUSION

Convoluted interactions occur between droplet size, carrier volume, and other application parameters. Recommendations for optimizing herbicide applications based on droplet size should be based on a site‐specific management approach to better account for these interactions. © 2018 Society of Chemical Industry
Induction of keratinocyte migration by ECa 233 is mediated through FAK/Akt, ERK, and p38 MAPK signaling
Authors: Singkhorn Sawana , Tantisira Mayuree H. , Tanasawet Supita , Hutamekalin Pilaiwanwadee , Wongtawatchai Tulaporn , Sukketsiri Wanida
Published: March 2018

Centella asiatica is widely considered the most important medicinal plant for treating and relieving skin diseases. Recently developed standardized extract of Centella asiatica ECa 233 has demonstrated positive effects on wound healing of incision and burn wound in rats. However, knowledge associated with wound healing mechanism of ECa 233 was scare. Therefore, this study aimed to investigate the effect and underlying molecular mechanisms of ECa 233 on the migration of a human keratinocyte cell line (HaCaT) using scratch wound healing assay. Formation of filopodia, a key protein in cell migration as well as signaling pathways possibly involved were subsequently assessed. It was found that HaCaT cell migration was significantly enhanced by ECa 233 in a concentration‐ and time‐dependent manner. The filopodia formations were accordingly increased in exposure to ECa 233 at concentrations of 0.1–100 μg/ml. Furthermore, ECa 233 was found to significantly upregulate the expression of Rac1 and RhoA and to induce phosphorylation of FAK and Akt as well as ERK and p38 MAPK. Taken all together, it is suggestive that ECa 233 induces cell migration and subsequently promotes wound healing activity, through the activation of FAK, Akt, and MAPK signaling pathways thereby supporting the role of ECa 233 to be further developed for the clinical treatment of wound.
A note on preconditioning weighted linear least‐squares, with consequences for weakly constrained variational data assimilation
Authors: Gratton Serge , Gürol Selime , Simon Ehouarn , Toint Philippe L.
Published: March 2018

The effect of preconditioning linear weighted least‐squares using an approximation of the model matrix is analyzed. The aim is to investigate from a theoretical point of view the inefficiencies of this approach as observed in the application of the weakly constrained 4D‐Var algorithm in geosciences. Bounds on the eigenvalues of the preconditioned system matrix are provided. It highlights the interplay of the eigenstructures of both the model and weighting matrices: maintaining a low bound on the eigenvalues of the preconditioned system matrix requires an approximation error of the model matrix which compensates for the condition number of the weighting matrix. A low‐dimension analytical example is given illustrating the resulting potential inefficiency of such preconditioners. The consequences of these results in the context of the state formulation of the weakly constrained 4D‐Var data assimilation problem are discussed. It is shown that the common approximations of the tangent linear model which maintain parallelization‐in‐time properties (identity or null matrix) can result in large bounds on the eigenvalues of the preconditioned matrix system.
Composite hierarchical antidisturbance control for a class of discrete‐time stochastic systems
Authors: Wei Xinjiang , Zhang Huifeng , Sun Shixiang , Karimi Hamid Reza
Published: March 2018

In this paper, antidisturbance control and estimation problem are discussed for a class of discrete‐time stochastic systems with nonlinearity and multiple disturbances, which include the disturbance with partially known information and a sequence of random vectors. A disturbance observer is constructed to estimate the disturbance with partially known information. A composite hierarchical antidisturbance control scheme is proposed by combining disturbance observer and H∞ control. It is proved that the 2 different disturbances can be rejected and attenuated, and the corresponding desired performances can be guaranteed for discrete‐time stochastic systems with known and unknown nonlinear dynamics, respectively. Simulation examples are given to demonstrate the effectiveness of the proposed scheme.
Reaction Tailoring for Synthesis of Phase‐Pure Nanocrystals of AgInSe2, Cu3SbSe3 and CuSbSe2
Authors: Kshirsagar Anuraj S. , Khanna Pawan. K.
Published: March 2018

Present article highlights synthesis of phase pure I, III, VI2 and I, V, VI2 ternary selenides nanocrystals (NCs) using oleic acid and oleyl amine capping agents. The synthesis of AgInSe2 (AISe), Cu3SbSe3 and CuSbSe2 (CSSe) NCs was executed by employing cyclohexeno‐1,2,3‐selenadiazole (SDZ) as Se precursor. The current study is the first report describing use of thermally labile organoselenium compound for the synthesis of such technologically important ternary selenide NCs. Systematic study of the formation of AISe and CSSe NCs at different reaction time is carried out in order to confirm phase purity and stoichiometry. The spherical, stoichiometric and NIR active semiconductors showed formation of orthorhombic crystal structure as confirmed from XRD analysis. It was observed that formation of phase pure AISe NCs requires 5 hours (h) of constant heating at about 220οC irrespective of the capping agents however, CuSbSe2 was obtained within an hour in presence of oleyl amine at same reaction temperature. Nanocrystals were characterized by different analytical tools such as UV‐Visible spectroscopy, FTIR, XRD, SEM/EDS, TEM, particle size and XPS analysis. Based on the results, possible chemical reaction pathway for ternary chalcogenide is presented.
Multicomponent‐Reaction‐ (MCR‐) Assisted Synthesis of a Coumarin‐Based Deep Blue Emitter for OLEDs and Related Applications
Authors: Puthumana Shyam Shankar Eramangalam , Damodaran Bahulayan
Published: March 2018

The lighting and display solutions of the future are Organic Light Emitting Diodes (OLEDs). For the electron transportation, hole transportation and light emission, sequential layers of specially designed organic molecules and materials are used in OLEDs. The perfect blue‐emitters showing CIE (Commission Internationale de l′Eclairage) coordinates with a y‐component smaller than 0.1 are highly desired for OLED technology. Herein we report an efficient step economic protocol for the synthesis of a deep blue emitting fluorescent molecule named as “Ugi EML BLUE” (λems 443 nm; C.I.E. X=0.162, Y=0.012; HOMO/LUMO=‐5.94 eV/‐1.60 eV) suitable for the emissive layers (EML) of OLEDs and related applications.
Evaluation of Anticancer Activity of Water‐Soluble Curcumin through the Induction of Apoptosis by p53 and p21 Modulation
Authors: Banuppriya Govindharasu , Shakambari Ganeshan , Sribalan Rajendran , Varalakshmi Perumal , Padmini Vediappen
Published: March 2018

Amide containing water soluble curcumin derivatives were synthesized and studied for their anti‐cancer activity. The synthesized water soluble compounds were cytotoxic when tested in vitro on HeLa cell and induced a p53 mediated apoptosis as evidenced by immunoblot analysis. Further DNA binding studies were also carried out to investigate the interaction between these synthesized curcumin compounds and HS‐DNA. The binding constant values (0.8167X104 M−1of 5a, 0.5443 X103 M−1 of 5b) suggested a good binding propensity to DNA. Physical properties such as stability, solubility, and log p values were investigated for the synthesized compounds.
Selective Synthesis of Ni(II) and Pd(II) Complexes with either ‘Normal’ or ‘Abnormal’ N‐Heterocyclic Carbene Coordination Modes
Authors: Tan Kel Vin , Li Zili , Karmis Rebecca E. , Barnard Peter J.
Published: March 2018

A family of Ni(II) and Pd(II) complexes of one bidentate and three tetradentate, N‐heterocyclic carbene (NHC) / amidate ligands have been prepared. The imidazolium salt pro‐ligands used in the synthesis of these complexes were designed to facilitate the ‘abnormal’ NHC coordination mode, through the introduction of either (1) methyl blocking group at the C2 position of the imidazolium units or (2) sterically demanding tert‐butyl imidazolium wingtip substituents or (3) the ligand was macrocyclic in nature. In all cases, the desired complexes were uncharged, with square‐planar coordination geometries about the metal centres. These studies showed that in the case of Ni(II), abnormal NHC complexes could be formed for the C2‐blocked tetradentate ligands only. In contrast for Pd(II), ‘abnormal’ NHC complexes could be prepared from C2‐blocked bidentate and tetradentate ligands with sterically demanding tert‐butyl NHC wingtip substituents. For the macrocyclic tetradentate ligand, Ni(II) and Pd(II) complexes displaying the ‘normal’ NHC coordination mode were obtained.