bluuebunny/crossref_metadata_2025_split huggingface dataset:
Models and Finite Elements for Thin‐Walled Structures
Authors: Bischoff Manfred , Ramm E. , Irslinger J. 
Published: December 2017

AbstractThis chapter is a revised, updated, and extended version of the chapter with the same title in the first issue of the “Encyclopedia of Computational Mechanics.” It provides an overview of modeling and discretization aspects in finite element analysis of thin‐walled structures. Shell formulations based on derivation from three‐dimensional continuum mechanics, the direct approach, and the degenerated solid concept are compared, highlighting conditions for their equivalence.Rather than individually describing the innumerable contributions to theories and finite element formulations for plates and shells, the essential assumptions in modeling and discretization, along with their consequences, are discussed. It is hoped that this approach comprises a good amount of the existing literature by including most concepts in a generic format.The contribution focuses on nonlinear finite element formulations for large displacements and rotations in the context of elastostatics, including some remarks on stability. Problems involving material nonlinearities and dynamics are other important topics, but these are outside the scope of the present chapter.
Buckling
Authors: Riks Eduard 
Published: December 2017

AbstractAlthough the first known solution of a buckling problem was given by the outstanding Swiss ‘natural philosopher’ Leonhard Euler (1744), buckling theory as an engineering subject is an outgrowth of a development that was established during the last century. The overview of the present knowledge regarding the computational analysis of buckling problems is here given in the context of the theory's most important historical developments.
Computational Structural Dynamics
Authors: Hulbert Gregory M. 
Published: December 2017

AbstractThis chapter presents an overview and a state‐of‐the art compilation of time integration methods for solving problems of dynamics, with a particular focus on developments that have occurred during the past 25 years. Various classifications of time integration algorithms are provided that assist the reader in understanding the many different types of numerical methods available for solving time‐dependent problems. Time integration algorithms for linear structural dynamics are reviewed thoroughly, from classical Newmark‐type schemes, to recent developments in time finite element‐based approaches. The distinction between linear and nonlinear dynamics is articulated and numerical methods developed for direct application towards solving nonlinear dynamics probems are presented. The chapter concludes with guidelines towards selecting an appropriate time integration method, along with guidelines towards choosing appropriate time step sizes.
Computational Modeling of Damage and Failures in Composite Laminates
Authors: Reddy J. N. , Robbins D. H. 
Published: December 2017

AbstractThis chapter is intended to provide an overview of issues that are important in the computational modeling of progressive damage and failure in fiber‐reinforced composite laminates. Owing to space limitations, the discussion mainly focuses on those models and methods that have been effectively used by the authors to address this particular class of problems, with references given to other viable models and methods. Topics covered in this chapter are as follows. An introduction and overview of fiber‐reinforced composite laminates, with emphasis on the multiscale nature of this class of materials, is presented in Section 1. Section 2 contains an overview of mathematical models that are commonly used to represent the mechanical behavior of composite laminates. These models constitute a natural hierarchy of models ranging from the simplest two‐dimensional plate model that only represents in‐plane behavior to a fully three‐dimensional layerwise model that includes discrete layer transverse shear and transverse normal effects. In Section 3, an overview of damage and failure models that have been used for composite laminates is presented. Discussion of the coupling between the macroscale and the microscale is presented in Section 4. This micro/macro coupling is achieved through the processes ofhomogenizationandlocalization. Homogenization is the process of determining homogeneous anisotropic material properties that effectively represent the average behavior of the heterogeneous fiber/matrix composite material. Localization is the process of determining the microscopic distribution of stress and strain based on a known macroscopic solution. These topics are discussed in the context of both infinitesimal and finite deformation. Finally, Section 5 is devoted to the description of possible approaches for the modeling of progressive damage. In particular, the discussion focuses on the application of continuum damage mechanics to the homogenized material description used for individual composite laminae. This particular methodology is chosen on the basis of its computational practicality coupled with its ability to describe stiffness reduction to a level of accuracy that is sufficient for a large class of problems. The last section, Section 6 (new with this volume), is concerned with the use of simultaneous, multiple laminate models in simulating progressive damage and global collapse of laminates subjected to combined bending and transverse shear deformation.
Dynamic Multilevel Methods and Turbulence
Authors: Dubois Thierry , Jauberteau Francois , Temam Roger M. 
Published: December 2017

AbstractIn this chapter, we describe numerical multilevel methods applied to the Navier–Stokes equations (homogeneous isotropic turbulence and channel flow problem), to the shallow water equations (geophysical problems), and to the renormalization of small eddies. The first difficulties with multilevel methods is to separate the scales. In this work, various cases are considered: the case of spectral methods, the case of finite difference methods, and the case of finite element methods. Then the numerical treatment is adapted to the size of the computed scales. The aim is to obtain new schemes, with better modeling properties and improved numerical stability. The spectral case is studied in detail, and the results of numerical simulations are reported in this case.Multilevel numerical methods are indispensable for the approximation of phenomena involving a large number of scales, such as turbulence. Although the methods described in this chapter are generally limited to two levels, they can, as explained in the text, be extended to a more important number of levels, thus extending significantly their performances.
Turbulence Direct Numerical Simulation and Large‐Eddy Simulation
Authors: Sagaut Pierre 
Published: December 2017

AbstractThis chapter deals with direct numerical simulation and large‐eddy simulation (LES) of turbulent flows, which are two techniques for the unsteady three‐dimensional simulation of turbulent motion. For the sake of clarity and brevity, the present framework is restricted to Newtonian, single‐phase, single‐species fluids. Both compressible and incompressible cases are considered. Numerical requirements for both these approaches are discussed, including grid resolution and control of numerical errors. The specific problem of compressible flows with shocks is detailed. The problem of the definition of the filtering procedure and subgrid models for the LES approach is presented, and the main theoretical and practical solutions are given. The difficult question of the definition of boundary conditions is also considered, with emphasis on turbulent inflow conditions and wall stress models. The last section is devoted to the presentation of the evolution of the application of these two techniques.
Retrograde interferon‐gamma signaling induces major histocompatibility class I expression in human‐induced pluripotent stem cell‐derived neurons
Authors: Clarkson Benjamin D. S. , Patel Misha S. , LaFrance‐Corey Reghann G. , Howe Charles L. 
Published: December 2017

AbstractObjectiveInjury‐associated axon‐intrinsic signals are thought to underlie pathogenesis and progression in many neuroinflammatory and neurodegenerative diseases, including multiple sclerosis (MS). Retrograde interferon gamma (IFNγ) signals are known to induce expression of major histocompatibility class I (MHC I) genes in murine axons, thereby increasing the susceptibility of these axons to attack by antigen‐specific CD8+ T cells. We sought to determine whether the same is true in human neurons.MethodsA novel microisolation chamber design was used to physically isolate and manipulate axons from human skin fibroblast‐derived induced pluripotent stem cell (iPSC)‐derived neuron‐enriched neural aggregates. Fluorescent retrobeads were used to assess the fraction of neurons with projections to the distal chamber. Axons were treated with IFNγ for 72 h and expression of MHC class I and antigen presentation genes were evaluated by RT‐PCR and immunofluorescence.ResultsHuman iPSC‐derived neural stem cells maintained as 3D aggregate cultures in the cell body chamber of polymer microisolation chambers extended dense axonal projections into the fluidically isolated distal chamber. Treatment of these axons with IFNγ resulted in upregulation of MHC class I and antigen processing genes in the neuron cell bodies. IFNγ‐induced MHC class I molecules were also anterogradely transported into the distal axon.InterpretationThese results provide conclusive evidence that human axons are competent to express MHC class I molecules, suggesting that inflammatory factors enriched in demyelinated lesions may render axons vulnerable to attack by autoreactive CD8+ T cells in patients with MS. Future work will be aimed at identifying pathogenic anti‐axonal T cells in these patients.
Enzymatically Produced miR34a Nanoparticles for Enhanced Antiproliferation Activity
Authors: Kim Hyejin , Lee Eunju , Kang Yoon Young , Song Jihyun , Mok Hyejung , Lee Jong Bum 
Published: December 2017

AbstractAmong a range of functional forms of RNA, microRNAs (miRNAs) have held a great promise for their natural ability to influence cellular behavior by regulating gene expression. In particular, it is revealed that miR34a has a function as a tumor suppressor by regulating silent information regulator 1 expression, causing antiproliferation of tumor. To utilize functional miR34a as an effective cancer therapeutics, an enzymatic approach to synthesize miR34a nanoparticles is adapted. The enzymatically self‐assembled miR34a nanoparticles have a high cargo capacity and a suitable size for cellular uptake. Indeed, the miR34a nanoparticles are delivered successfully to PC3 cells, human prostate cancer cells, and suppress proliferation and migration of those cells. These results suggest that the enzymatically produced miR34a nanoparticles can function as an effective tumor suppressor. Furthermore, it is expected that the enzymatic synthesis of miRNA nanoparticles can be adapted universally for delivery of other functional miRNAs as well.
Periosteum Extracellular‐Matrix‐Mediated Acellular Mineralization during Bone Formation
Authors: Lin Xianfeng , Zhao Chenchen , Zhu Peizhi , Chen Jiaxin , Yu Huaguang , Cai Yin , Zhang Qi , Qin An , Fan Shunwu 
Published: December 2017

AbstractCell‐mediated mineralization is essential for bone formation and regeneration. In this study, it is proven that extracellular matrix (ECM) of decellularized periosteum can play an initiative and independent role in bone‐like apatite formation. Using decellularized periosteum scaffold, it is revealed that ECM scaffold itself can promote critical bone defect regeneration and nude mouse ectopic ossification. The natural collagen matrix of decellularized periosteum can serve as a 3D structural template for Ca–P nuclei initiation, controlling the size and orientation of bone‐like mineral crystals. The naturally cross‐linked and highly ordered 3D fibrillar network of decellularized periosteum not only provides a model for mimicking mineralization in vitro and in vivo to elucidate the important functions of ECM in bone formation and regeneration, but also can be a promising biomaterial for bone tissue engineering and clinical application.
Cytokine Profiling of Primary Human Macrophages Exposed to Endotoxin‐Free Graphene Oxide: Size‐Independent NLRP3 Inflammasome Activation
Authors: Mukherjee Sourav P. , Kostarelos Kostas , Fadeel Bengt 
Published: December 2017

AbstractGraphene‐based materials including graphene oxide (GO) are envisioned for a variety of biomedical applications. However, there are conflicting results concerning the biocompatibility of these materials. Here, a question is raised whether GO with small or large lateral dimensions triggers cytotoxicity and/or cytokine responses in primary human monocyte‐derived macrophages. GO sheets produced under sterile conditions by a modified Hummers' method are found to be taken up by macrophages without signs of cytotoxicity. Then, multiplex arrays are used for profiling of proinflammatory and anti‐inflammatory responses. Notably, GO suppresses the lipopolysaccharide (LPS)‐triggered induction of several chemokines and cytokines, including the anti‐inflammatory cytokine, interleukin‐10 (IL‐10). No production of proinflammatory TNF‐αis observed. However, GO elicits caspase‐dependent IL‐1βexpression, a hallmark of inflammasome activation, in LPS‐primed macrophages. Furthermore, GO‐triggered IL‐1 βproduction requires NADPH oxidase‐generated reactive oxygen species and cellular uptake of GO and is accompanied by cathepsin B release and K+ efflux. Using THP‐1 knockdown cells, a role for the inflammasome sensor, NLRP3, the adaptor protein, ASC, and caspase‐1 for GO‐induced IL‐1βsecretion is demonstrated. Finally, these studies show that inflammasome activation is independent of the lateral dimensions of the GO sheets. These studies provide novel insights regarding the immunomodulatory properties of endotoxin‐free GO.
A Black Phosphorus Carbide Infrared Phototransistor
Authors: Tan Wee Chong , Huang Li , Ng Rui Jie , Wang Lin , Hasan Dihan Md. Nuruddin , Duffin Thorin Jake , Kumar Karuppannan Senthil , Nijhuis Christian A. , Lee Chengkuo , Ang Kah‐Wee 
Published: December 2017

AbstractPhotodetectors with broadband detection capability are desirable for sensing applications in the coming age of the internet‐of‐things. Although 2D layered materials (2DMs) have been actively pursued due to their unique optical properties, by far only graphene and black arsenic phosphorus have the wide absorption spectrum that covers most molecular vibrational fingerprints. However, their reported responsivity and response time are falling short of the requirements needed for enabling simultaneous weak‐signal and high‐speed detections. Here, a novel 2DM, black phosphorous carbide (b‐PC) with a wide absorption spectrum up to 8000 nm is synthesized and a b‐PC phototransistor with a tunable responsivity and response time at an excitation wavelength of 2004 nm is demonstrated. The b‐PC phototransistor achieves a peak responsivity of 2163 A W−1 and a shot noise equivalent power of 1.3 fW Hz−1/2 at 2004 nm. In addition, it is shown that a response time of 0.7 ns is tunable by the gating effect, which renders it versatile for high‐speed applications. Under the same signal strength (i.e., excitation power), its performance in responsivity and detectivity in room temperature condition is currently ahead of recent top‐performing photodetectors based on 2DMs that operate with a small bias voltage of 0.2 V.
Recent Progress in Porous Graphene and Reduced Graphene Oxide‐Based Nanomaterials for Electrochemical Energy Storage Devices
Authors: Hooch Antink Wytse , Choi Yejung , Seong Kwang‐dong , Kim Jong Min , Piao Yuanzhe 
Published: December 2017

AbstractGraphene‐based nanocomposites are characterized by high mechanical strength, excellent electrical conductivity, and outstanding thermal and chemical stability. Additionally, the combination of versatile functionalization chemistry and simplicity of large‐scale synthesis makes graphene ideal for electrode materials for energy storage devices. To improve the electrochemical performance even further, recent research has focused on the preparation of porous graphene structures, either by creating holes in the graphene sheets or by assembling them into a 3D porous framework. Porous graphene and reduced graphene oxide allow for rapid ion diffusion and display high real surface area. In this review paper, the conventional methods for the preparation of porous graphene are summarized and recent progress in porous graphene‐based nanomaterials for electrochemical energy storage devices is discussed.
The social cost of the Black Saturday bushfires
Authors: Ambrey Christopher L. , Fleming Christopher M. , Manning Matthew 
Published: December 2017

AbstractThe Intergovernmental Panel on Climate Change have predicted with high confidence that the risk of bushfires will increase in the future. As this risk increases, so too does the need for appropriate policy responses. In developing these responses, costs need to be weighed against benefits. To fully appreciate the benefits of bushfire risk mitigation policies and strengthen the development of social policies around such events, it is necessary to include the psychological cost of experiencing these events. In this study, we employ the ‘life satisfaction approach’ to place a monetary estimate on the cost of Australia's Black Saturday bushfires (Australia's worst bushfires on record). Results reveal that the bushfires significantly reduce self‐reported levels of life satisfaction, with an implied willingness‐to‐pay of AUD 2,991 in terms of annual household income, or AUD 1,039 per capita, to reduce by one percent the extent to which an individual's immediate local area was affected by the Black Saturday bushfires. In doing so, we identify an apparent gap between current levels of expenditure on bushfire response and mitigation, and that amount which (with the inclusion of associated social benefits) would be welfare maximising.
Synthesis of Difluoromethylthioesters from Aldehydes
Authors: Guo Shi‐Huan , Zhang Xing‐Long , Pan Gao‐Fei , Zhu Xue‐Qing , Gao Ya‐Ru , Wang Yong‐Qiang 
Published: December 2017

AbstractDifluoromethylthioester compounds are yet another important kind of organofluorine compound and are reported here for the first time. They can be efficiently synthesized from various aldehydes. The synthetic method features mild reaction conditions, good tolerance of functional groups, broad substrate scope, and importantly, no metal is involved in the reaction. The approach has the potential to become an important tool for the late‐stage functionalization of advanced synthetic intermediates, and should have many applications in medicinal chemistry.
Core–Shell Structuring of Pure Metallic Aerogels towards Highly Efficient Platinum Utilization for the Oxygen Reduction Reaction
Authors: Cai Bin , Hübner René , Sasaki Kotaro , Zhang Yuanzhe , Su Dong , Ziegler Christoph , Vukmirovic Miomir B. , Rellinghaus Bernd , Adzic Radoslav R. , Eychmüller Alexander 
Published: December 2017

AbstractThe development of core–shell structures remains a fundamental challenge for pure metallic aerogels. Here we report the synthesis of PdxAu‐Pt core–shell aerogels composed of an ultrathin Pt shell and a composition‐tunable PdxAu alloy core. The universality of this strategy ensures the extension of core compositions to Pd transition‐metal alloys. The core–shell aerogels exhibited largely improved Pt utilization efficiencies for the oxygen reduction reaction and their activities show a volcano‐type relationship as a function of the lattice parameter of the core substrate. The maximum mass and specific activities are 5.25 A mgPt−1 and 2.53 mA cm−2, which are 18.7 and 4.1 times higher than those of Pt/C, respectively, demonstrating the superiority of the core–shell metallic aerogels. The proposed core‐based activity descriptor provides a new possible strategy for the design of future core–shell electrocatalysts.
The Ego's Habitus: An Examination of the Role Culture Plays in Structuring the Ego
Authors: Dajani Karim G. 
Published: December 2017

AbstractThe cultural anthropologist Pierre Bourdieu developed a conception of culture or habitus that can greatly expand our understanding of how the collective and trans‐individual contributes to structuring the mind, conditioning the body and shaping experience from moment to moment. A synthesis of Pierre Bourdieu's conception of culture or habitus with Freud's conception of the ego clearly demonstrates that culture structures the ego's nucleus. Cultural propositions are inculcated into the ego in the form of dispositions that determine how things are perceived and understood within a large‐group. Mental structures derived from culture are located within the unconscious but not repressed ego in a “third” type of unconscious that Freud discovered but did not elaborate. Deepening our understanding of how culture connects the individual with the collective can help us reach previously overlooked areas of experience in our patients and, perhaps, develop methods for addressing pathogenic cultural attitudes.
Taurine, caffeine, and energy drinks: Reviewing the risks to the adolescent brain
Authors: Curran Christine Perdan , Marczinski Cecile A. 
Published: December 2017

AbstractEnergy drinks are emerging as a major component of the beverage market with sales projected to top $60 billion globally in the next five years. Energy drinks contain a variety of ingredients, but many of the top‐selling brands include high doses of caffeine and the amino acid taurine. Energy drink consumption by children has raised concerns, due to potential caffeine toxicity. An additional risk has been noted among college‐aged consumers of energy drinks who appear at higher risk of over‐consumption of alcohol when the two drinks are consumed together. The differential and combinatorial effects of caffeine and taurine on the developing brain are reviewed here with an emphasis on the adolescent brain, which is still maturing. Key data from animal studies are summarized to highlight both reported benefits and adverse effects reported following acute and chronic exposures. The data suggest that age is an important factor in both caffeine and taurine toxicity. Although the aged or diseased brain might benefit from taurine or caffeine supplementation, it appears that adolescents are not likely to benefit from supplementation and may, in fact, suffer ill effects from chronic ingestion of high doses. Additional work is needed though to address gaps in our understanding of how taurine affects females, since the majority of animal studies focused exclusively on male subjects.
Exercise, cognition, and the adolescent brain
Authors: Herting Megan M. , Chu Xiaofang 
Published: December 2017

AbstractBackgroundFew adolescents engage in the recommended levels of physical activity, and daily exercise levels tend to drastically decrease throughout adolescence. Beyond physical health benefits, regular exercise may also have important implications for the teenage brain and cognitive and academic capabilities.MethodsThis narrative review examines how physical activity and aerobic exercise relate to school performance, cognition, and brain structure and function.ResultsA number of studies have found that habitual exercise and physical activity are associated with academic performance, cognitive function, brain structure, and brain activity in adolescents. We also discuss how additional intervention studies that examine a wide range of neurological and cognitive outcomes are necessary, as well as characterizing the type, frequency, and dose of exercise and identifying individual differences that contribute to how exercise may benefit the teen brain.ConclusionsRoutine exercise relates to adolescent brain structure and function as well as cognitive performance. Together, these studies suggest that physical activity and aerobic exercise may be important factors for optimal adolescent brain development.