bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced Structural Materials and Cladding
Authors: Allen T. , Burlet H. , Nanstad R.K. , Samaras M. , Ukai S. 
Published: February 2011

AbstractAdvanced nuclear energy systems, both fission- and fusion-based, aim to operate at higher temperatures and greater radiation exposure levels than experienced in current light water reactors. Additionally, they are envisioned to operate in coolants such as helium and sodium that allow for higher operating temperatures. Because of these unique environments, different requirements and challenges are presented for both structural materials and fuel cladding. For core and cladding applications in intermediate-temperature reactors (400–650°C), the primary candidates are 9–12Cr ferritic–martensitic steels (where the numbers represent the weight percentage of Cr in the material, i.e., 9–12 wt%) and advanced austenitic steels, adapted to maximize high-temperature strength without compromising lower temperature toughness. For very high temperature reactors (>650°C), strength and oxidation resistance are more critical. In such conditions, high-temperature metals as well as ceramics and ceramic composites are candidates. For all advanced systems operating at high pressures, performance of the pressure boundary materials (i.e., those components responsible for containing the high-pressure liquids or gases that cool the reactor) is critical to reactor safety. For some reactors, pressure vessels are anticipated to be significantly larger and thicker than those used in light water reactors. The properties through the entire thickness of these components, including the effects of radiation damage as a function of damage rate, are important. For all of these advanced systems, optimizing the microstructures of candidate materials will allow for improved radiation and high-temperature performance in nuclear applications, and advanced modeling tools provide a basis for developing optimized microstructures.
Graphite, Ceramics, and Ceramic Composites for High-Temperature Nuclear Power Systems
Authors: Bonal Jean-Pierre , Kohyama Akira , van der Laan Jaap , Snead Lance L. 
Published: February 2011

AbstractThe age of nuclear power originated with the gas-cooled, graphite-moderated reactor in the 1940s. Although this reactor design had intrinsic safety features and enjoyed initial widespread use, gas-cooled reactor technology was supplanted by higher power density water-cooled systems in the 1960s. However, the next-generation reactors seek enhanced power conversion efficiency and the ability to produce hydrogen, best accomplished with high-temperature gas-cooled systems. Thus, international interest in gas-cooled reactor systems is reemerging. Although the materials systems of these reactors are fairly simple, the reactor environment, particularly its high temperatures and intense irradiation, present extreme challenges in terms of material selection and survivability. This article provides a brief review of materials issues and recent progress related to graphite and ceramic materials for application in gas-cooled nuclear reactor environments. Of particular interest are the drastic, irradiation-induced microstructural evolution and thermophysical property changes occurring as a result of energetic neutron irradiation, which significantly impact the performance and lifetime of much of the reactor core. For “nuclear” graphite, the performance and lifetime not only are closely related to the irradiation environment but also are dramatically affected by the specifics of the particular graphite: manufacturing process, graphitization temperature, composition (amount of coke, filler, etc., depending on where it was mined), and so on. Moreover, the extreme environmental challenges set down by this next generation of fission nuclear plants have driven the development and application of ceramic composites for critical components, pushing beyond upper temperature limits set by metallic alloys used in previous generations of nuclear reactors. The composite material systems of particular interest are continuous carbon-fiber composites and newly developed radiation-resistant silicon carbide fiber composites.
Mechanical Regulation of Cells by Materials and Tissues
Authors: Thomas Wendy E. , Discher Dennis E. , Prasad Shastri V. 
Published: February 2011

AbstractOver the last dozen years, studies at the cell and tissue level have demonstrated that the function and fate of all cells, stem cells in particular, are affected by the collective physical properties of their microenvironments. Meanwhile, biophysical studies at the single molecule level have taught us a great deal about how mechanical forces affect the structure and function of proteins involved in the assembly of cells into tissues. Together, these molecular, cellular, and tissue studies provide insight into the process and importance of mechanotransduction, which is the process by which mechanical forces are transduced into biological signals. This insight should motivate biomimetic approaches to better control cell fate and tissue function.
Functional Tissue Engineering Through Biofunctional Macromolecules and Surface Design
Authors: Moroni Lorenzo , Habibovic Pamela , Mooney David J. , van Blitterswijk Clemens A. 
Published: February 2011

AbstractTissue engineering is a rapidly developing discipline that has already entered the clinics and will tremendously change patient management in the near future. The aim of classical tissue engineering is to heal damaged or diseased tissues and organs through the combination of cells, biological factors, and porous biomaterials. The resulting, engineered tissue must possess appropriate functional properties to replace or supplement the targeted tissue. This is still a challenge to overcome before tissue-engineered products can be considered a complete success. Classical tissue engineering approaches rely on the use of mature cells expandedin vitroand transplanted alone or seeded in passive 3D scaffolds, which can lead to the loss of cellular phenotype and production of nonfunctional extracellular matrix. An emerging strategy involves the design of bioactive 3D scaffolds with instructive properties able to recruit cellsin situand direct tissue formation. Here, we present and discuss recent efforts to achieve smart scaffolds encompassing macromolecular biofunctionalization and surface design.
Polymer Behavior at the Air-Water Interface
Authors: Gargallo Ligia 
Published: February 2011

AbstractThis article reviews polymer behavior at the air-water interface with a focus on the Langmuir technique and spreading processes to gain insight into this interface. The influence of the solvent and the water subphase on some polymer monolayers is discussed. The surface pressure–area isotherms (π–A) are described in terms of the chemical structure and the hydrophilic-hydrophobic balance of selected polymeric systems, with an emphasis on the behavior of the specific diblock copolymer films at the air-water interface. In some cases, molecular dynamic simulation studies can be used to visualize the organization and orientation of polymers at the air-water interface and to identify the main molecular interactions involved in such processes.
Shape and Biomechanical Characteristics of Human Red Blood Cells in Health and Disease
Authors: Diez-Silva Monica , Dao Ming , Han Jongyoon , Lim Chwee-Teck , Suresh Subra 
Published: February 2011

AbstractThe biconcave shape and corresponding deformability of the human red blood cell (RBC) is an essential feature of its biological function. This feature of RBCs can be critically affected by genetic or acquired pathological conditions. In this review, we highlight new dynamicin vitroassays that explore various hereditary blood disorders and parasitic infectious diseases that cause disruption of RBC morphology and mechanics. In particular, recent advances in high-throughput microfluidic devices make it possible to sort/identify healthy and pathological human RBCs with different mechanobiological characteristics.
Electronic Properties of Organic-Based Interfaces
Authors: Kronik Leeor , Koch Norbert 
Published: February 2011

AbstractOrganic-based interfaces can possess a range of surprising electronic properties that are of intense interest from both the basic science and the applied research points of view. In this issue of MRS Bulletin, we provide state-of-the-art overviews of selected topics involving three complementary aspects of the electronic properties of organic-based interfaces: the nascent electronics technologies that would gain from improved understanding and control of such interfaces; the novel properties that organic-based interfaces may possess; and the experimental and theoretical challenges afforded by such studies.
Van der Waals Interactions Between Organic Adsorbates and at Organic/Inorganic Interfaces
Authors: Tkatchenko Alexandre , Romaner Lorenz , Hofmann Oliver T. , Zojer Egbert , Ambrosch-Draxl Claudia , Scheffler Matthias 
Published: February 2011

AbstractVan der Waals (vdW) interactions play a prominent role in the structure and function of organic/organic and organic/inorganic interfaces. Their accurate determination from first principles, however, is a notoriously difficult task. Recently, a surge of interest in modeling vdW interactions has led to promising theoretical developments. This article reviews the state-of-the-art of describing vdW interactions by density-functional theory with respect to accuracy and practicability. The performance of the different methods is demonstrated for simple systems, such as rare-gas dimers and small organic molecules. The nature of binding at organic/inorganic interfaces is then exemplified for the perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) molecule at surfaces of coinage metals. This fundamental system is the best-characterized organic molecule/metal interface in experiment and theory. We emphasize the crucial importance of a balanced description of both geometry and electronic structure in order to understand and model the properties of such systems. Finally, the relevance of vdW interactions to the function of actual devices based on interfaces is discussed.
Organic Electronics at the Interface with Biology
Authors: Owens Róisín M. , Malliaras George G. 
Published: February 2011

AbstractThe emergence of organic electronics represents one of the most dramatic technological developments of the past two decades. Perhaps the most important frontier of this field involves the interface with biology. The “soft” nature of organics offers better mechanical compatibility with tissue than traditional electronic materials, while their natural compatibility with mechanically flexible substrates suits the nonplanar form factors often required for implants. More importantly, the ability of organics to conduct ions in addition to electrons and holes opens up a new communication channel with biology. In this article, we consider a few examples that illustrate the coupling between organic electronics and biology and highlight new directions of research.
Phase Transitions in Thin Block Copolymer Films
Authors: Kramer Edward J. 
Published: February 2011

AbstractDavid Turnbull's experiments and theoretical insights paved the way for much of our modern understanding of phase transitions in materials. In recognition of his contributions, this lecture will concentrate on phase transitions in a material system not considered by Turnbull, thin diblock copolymer films. Well-ordered block copolymer films are attracting increasing interest as we attempt to extend photolithography to smaller dimensions. In the case of diblock copolymer spheres, an ordered monolayer is hexagonal, but the ordered bulk is body-centered cubic (bcc). There is no hexagonal plane in the bcc structure, so a phase transition must occur as n, the number of layers of spheres in the film, increases. How this phase transition occurs with nand how it can be manipulated is the subject of the first part of my presentation. In the second part of the talk, I show that monolayers of diblock copolymer spheres and cylinders undergo order-to-disorder transitions that differ greatly from those of the bulk. These ordered 2D monolayers are susceptible to phonon-generated disorder as well as to thermal generation of defects, such as dislocations, which, while they are line defects in 3D, are point defects in 2D. The results are compared to the theories of melting of 2D crystals (spheres) and of 2D smectic liquid crystals (cylinders), a comparison that will allow us to understand most, but not all, of the features of these order-disorder transitions that occur as the temperature is increased.
Overview of the Natural Space Environment and ESA, JAXA, and NASA Materials Flight Experiments
Authors: Edwards David L. , Tighe Adrian P. , Eesbeek Marc Van , Kimoto Yugo , de Groh Kim K. 
Published: February 2011

AbstractSpace environmental effects on materials are very severe and complex because of the synergistic interaction of orbital environments such as high-energy radiation particles, atomic oxygen, micrometeoroids, orbital debris, and ultraviolet irradiation interacting synergistically, along with thermal exposure. In addition, surface degradation associated with contamination can negatively impact optics performance. Materials flight experiments are critical to understanding the engineering performance of materials exposed to specific space environments. Likewise, the spacecraft designer must have an understanding of the specific environment in which a spacecraft will operate, enabling appropriate selection of materials to maximize engineering performance, increase mission lifetimes, and reduce risk. This article will present a methodology for assessing the engineering performance of materials baselined for a specific spacecraft or mission. In addition, an overview of the space environment, from low Earth orbit to interplanetary space, will be provided along with an overview on the effects of the space environment on materials performance. The majority of this article is devoted to materials flight experiments from the European Space Agency (ESA), the Japan Aerospace Exploration Agency (JAXA), and from the National Aeronautics and Space Administration (NASA). Some of the experiments reviewed include ESA's Materials Exposure and Degradation Experiment on the International Space Station (ISS), JAXA's Micro-Particles Capturer and Space Environment Exposure Device experiments on the ISS Service Module and on the ISS Japanese Experiment Module Exposed Facility, and NASA's Long Duration Exposure Facility satellite and the Materials International Space Station Experiment series flown on the exterior of ISS.
Mechanistic Studies of Atomic Oxygen Reactions with Polymers and Combined Effects with Vacuum Ultraviolet Light
Authors: Tagawa Masahito , Minton Timothy K. 
Published: February 2011

AbstractThis article focuses on mechanistic aspects of hyperthermal atomic oxygen reactions with polymers, which are the major contributor to material degradation in low Earth orbit. Due to the importance of well-controlled experiments in the understanding of the reaction mechanisms, ground-based experimental results obtained by a hyperthermal atomic oxygen beam generated by laser detonation facilities are mainly surveyed. Combined effects of atomic oxygen and vacuum ultraviolet (VUV) light on fluorinated polymers are also described. Such combined effects of hyperthermal atomic oxygen and VUV light are important not only from a fundamental point of view but also for engineering purposes (i.e., methodology for ground-based space environmental simulation). The VUV-sensitive polymers, poly(methyl methacrylate), and Teflon fluorinated ethylene-propylene do not show significant synergistic effects. Instead, the effect of combining atomic oxygen and VUV light produces erosion of the polymer that is the sum of the erosion caused by atomic oxygen and UV light acting individually. The experimental results suggest that material erosion in a complicated space environment may be quantitatively predicted if the erosion yields caused by the individual action of atomic oxygen and VUV light are known.
From Diatom Biomolecules to Bioinspired Syntheses of Silica- and Titania-Based Materials
Authors: Kröger Nils , Sandhage Kenneth H. 
Published: February 2011

AbstractAmorphous silica is (next to CaCO3) the second most abundant biologically produced inorganic material. A certain group of photosynthetic microalgae, called diatoms, forms complex 3D silica architectures (frustules) containing regularly arranged nanoscale features (pores, channels, protuberances). Recently, biomolecules involved in diatom silica formation have been characterized, and first insights into their structure-function correlations have been obtained. This has spurred the development of synthetic (bio)polymers capable of directing thein vitroformation of silica and other inorganic materials from aqueous precursor solutions under mild conditions. Here we present a summary of current insight into the mechanism of silica formation by diatom biomolecules and provide examples of synthetic (bio)polymers for the formation of silica and titania materials with complex structures.
Cellulose Biocomposites—From Bulk Moldings to Nanostructured Systems
Authors: Berglund Lars A. , Peijs Ton 
Published: February 2011

AbstractCellulose biocomposites are widely used in industry as a low-cost engineering material with plant fiber reinforcement. However, chemical and microstructural heterogeneity causes low strength, low strain-to-failure, high moisture sensitivity, and odor and discoloration problems. Efforts toward improved performance through fiber orientation control, increased fiber lengths, and biopolymer use are reviewed. Interfacial strength control and moisture sensitivity are remaining challenges. As an attractive alternative reinforcement, high-quality cellulose nanofibers obtained by wood pulp fiber disintegration can be prepared at low cost. These nanofibers have high length/diameter ratios, diameters in the 5–15 nm range, and intrinsically superior physical properties. Wood cellulose nanofibers are interesting as an alternative reinforcement to more expensive nanoparticles, such as carbon nanotubes. Nanopaper and polymer matrix nanocomposites based on cellulose nanofiber networks show high strength, high work-of-fracture, low moisture adsorption, low thermal expansion, high thermal stability, high thermal conductivity, exceptional barrier properties, and high optical transparency. The favorable mechanical performance of bioinspired foams and low-density aerogels is reviewed. Future applications of cellulose biocomposites will be extended from the high-volume/low-cost end toward high-tech applications, where cellulose properties are fully exploited in nanostructured materials.
Physics of Oxides for Future Devices
Authors: Scott James F. 
Published: February 2011

AbstractFerroelectric oxides underwent a renaissance in the 1980s and 1990s, driven by the success in commercializing thin-film ferroelectric random-access memory devices (FRAMs) for applications such as the SONY PlayStation 2 memory board. Materials scientists gravitated into this new field from magnetic oxides and from high-Tcsuperconductivity. But as the FRAM prospects wane and neither dynamic random-access memory devices nor FLASH memory has been replaced, we now require new directions for materials research on oxides. In this article, I outline briefly four new directions for ferroelectric oxide research: something old—ferroelectrically induced ferromagnetism and multiferroic switching; something new—THz emission from oxide ferroelectrics; something borrowed—Heisenberg-like switching of domains in nanoferroelectrics; and something blue—ZnO light-emitting devices. Magnetoelectricity—the linear coupling of polarization and magnetization—was theoretically predicted by Igor Dzyaloshinskii in 1957 and measured experimentally by Astrov two years later. It did not produce commercial devices. Although a flurry of new work occurred in the 1970s, emphasizing boracites—mostly by Hans Schmid in Geneva, no materials were found that exhibited large effects at room temperature. In the past decade, the search has been renewed, emphasizing rare earth systems such as Tb manganites.
Oral Impact on Daily Performance, Personality Traits, and Compliance in Periodontal Maintenance Therapy
Authors: Costa Fernando Oliveira , Miranda Cota Luís Otávio , Pereira Lages Eugênio José , Vilela Câmara Gislene Clemente , Cortelli Sheila Cavalca , Cortelli José Roberto , Costa José Eustáquio , Medeiros Lorentz Telma Campos 
Published: February 2011

Background: To our knowledge, the association between personality traits and oral health impacts on daily activities among patients under periodontal maintenance was not previously evaluated. The present study aims to determine the oral health impacts among regular‐ and erratic‐complier patients and their correlations with personality traits by means of the oral impacts on daily performance (OIDP) and the neuroticism extraversion openness five‐factor inventory (NEO FFI‐R) instruments.Methods: A total of 58 regular and 58 erratic compliers matched by sex, diabetes, and smoking were recruited from a cohort of 238 participants under periodontal maintenance. Periodontal examinations and questionnaire applications were performed in recalls during a 3‐year interval. The influence of variables of interest on the OIDP was evaluated through univariate and multivariate linear regression analyses.Results: The periodontal status of regular compliers was significantly better than that of erratic compliers. Erratic compliers presented higher OIDP scores (36.34 ± 6.64) compared to regular compliers (30.45 ± 7.72). Higher scores of neuroticism and conscientiousness (R2 = 68%; P <0.001) were associated with higher OIDP scores among regular compliers, whereas among erratic compliers, lower scores of neuroticism, higher openness, and extraversion (R2 = 77%; P = 0.001) were associated with higher OIDP scores.Conclusion: Personality traits, mainly neuroticism, showed significant influences on OIDP among patients under periodontal maintenance.
Cytokines and Bone‐Related Factors in Systemically Healthy Patients With Chronic Periodontitis and Patients With Type 2 Diabetes and Chronic Periodontitis
Authors: Vieira Ribeiro Fernanda , de Mendonça Adriana Cutrim , Santos Vanessa Renata , Bastos Marta Ferreira , Figueiredo Luciene Cristina , Duarte Poliana Mendes 
Published: February 2011

Background: This study compares the levels of cytokines and bone‐related factors in the gingival crevicular fluid (GCF) of systemically healthy patients with chronic periodontitis (CP); and better‐controlled, and poorly controlled patients with type 2 diabetes and CP.Methods: Thirty‐seven patients with type 2 diabetes and CP and 20 systemically healthy patients with CP were enrolled in this study. The patients with diabetes mellitus were categorized as better‐controlled (n = 17; HbA1c levels ≤8%) or poorly controlled (n = 20; glycated hemoglobin values >8%). Levels of tumor necrosis factor‐α, interleukin (IL)‐4, interferon (IFN)‐γ, IL‐23, IL‐17, soluble receptor activator of nuclear factor‐kappa B ligand (sRANKL), and osteoprotegerin (OPG) in GCF of diseased sites were analyzed by enzyme‐linked immunosorbent assay.Results: Type 2 diabetes mellitus, as a whole, upregulates the levels of OPG, sRANKL, IFN‐γ, IL‐17, and IL‐23 and downregulates the production of IL‐4 in sites with CP (P <0.05). Better‐controlled individuals exhibited the highest levels of IFN‐γ, whereas poorly controlled patients presented the highest levels of IL‐17 (P <0.05). There were no differences in the levels of tumor necrosis factor‐α, OPG, and IL‐23 among systemically healthy, better‐controlled, and poorly controlled patients with diabetes (P >0.05).Conclusions: Increased levels of proinflammatory cytokines and RANKL were observed in the GCF of patients with type 2 diabetes with CP, compared to patients without diabetes. In addition, poor or good glycemic status seems to modulate osteo‐immunoinflammatory mediators in a different manner.