bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Laser Sintering of Polycaprolactone Bone Tissue Engineering Scaffolds
Authors: Partee Brock , Hollister Scott J. , Das Suman 
Published: April 2011

ABSTRACTPresent tissue engineering practice requires porous, bioresorbable scaffolds to serve as temporary 3D templates to guide cell attachment, differentiation, and proliferation. Recent research suggests that scaffold material and internal architecture significantly influence regenerate tissue structure and function. However, lack of versatile biomaterials processing methods have slowed progress towards fully testing these findings. Our research investigates using selective laser sintering (SLS) to fabricate bone tissue engineering scaffolds. Using SLS, we have fabricated polycaprolactone (PCL) and polycaprolactone/tri-calcium phosphate composite scaffolds. We report on scaffold design and fabrication, mechanical property measurements, and structural characterization via optical microscopy and micro-computed tomography.
Formation of Intermetallic-Ceramic Composites from Nanoreactants in a Self-Sustaining Reaction Regime
Authors: Dargar Shivanee R. , Groven Lori J. , Swiatkiewicz Jacek J. , Puszynski Jan A. 
Published: April 2011

ABSTRACTProcessing of nanoreactant energetic system, Al-TiO2, in the thermal explosion mode of combustion synthesis was investigated. Simultaneous combustion synthesis and densification experiments were carried out in a uniaxial press to obtain homogeneous as well as functionally graded products of the above reactant system. It was demonstrated that TiAl3-Al2O3 composite product synthesized from Al-TiO2 reactant system retained its sub-microstructure despite a short term exposure to higher temperatures. Composite materials with densities of 96–98% of the theoretical densities were obtained. The effect of several key processing parameters such as initial composition of reactants and temperature-pressure conditions on morphology of combustion synthesized product, their phase composition, and residual porosity were investigated. DSC, XRD, SEM, and LIBS analyses were used to characterize both reactants and products.
Sol-gel synthesis of silica–based mesoporous powders
Authors: Armelao Lidia , Bottaro Gregorio , Campostrini Renzo , Gialanella Stefano , Ischia Marco , Poli Fabrizia , Tondello Eugenio 
Published: April 2011

ABSTRACTMesoporous silica powders have been synthesized starting from aqueous solutions of Si(OCH2CH3)4 (TEOS) under acidic conditions, using non-ionic alkyl poly(ethylene oxide) oligomer (Brij76) as a structure-directing agent. Template removal was performed by thermal treatment in air as well as by ethanol extraction. The annealing process (400 - 600°C) resulted in more efficient elimination of the organic molecules, thus yielding hexagonal (p6mm) mesopor-ous materials with pore volume and specific surface area ranging between 0.58 – 0.41 cm3/g and 900 – 700 m2/g, respectively. The systems were characterized by X-Ray Diffraction (XRD), N2 BET adsorption, Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Particular attention was focused on the evolution of the system mesostructural and porous features as a function of the template removal procedure. The obtained mesoporous networks are suitable as matrices for the development of nanocomposite systems in which the dispersion or the growth of various guest species (clusters, molecules…) can be addressed into the host mesopores.
Dielectric Constant of Barium Titanate Synthesized by Containerless Processing
Authors: Yu Jianding , Paradis Paul-François , Ishikawa Takehiko , Yoda Shinichi 
Published: April 2011

ABSTRACTContainerless processing is an attractive synthesis technique that permits deep undercooling and provides the possibility to solidify the undercooled liquid into a selected phase, and to synthesize materials with novel properties. Spheroidal BaTiO3samples with a diameter of approximately 2mm were solidified by containerless processing, using an electrostatic levitation apparatus. Single crystal hexagonal BaTiO3and polycrystalline perovskite BaTiO3were successfully synthesized at different undercoolings levels. An oxygen-deficient single crystal of hexagonal BaTiO3obtained with this method, exhibited a giant permittivity higher than 100000, with a loss component tanδof about 0.1 at room temperature. The permittivity showed weak temperature dependence in the 70 K to 300 K range, and a dramatic drop by 2 orders of magnitude below 70 K. In comparison, the polycrystalline perovskite BaTiO3showed a permittivity of 4000 at room temperature.
Ag–B Thin Films Prepared by Magnetron Sputtering
Authors: Metz Oren , Pelleg Joshua , Sinder Misha , Shneck Roni , Sokolovsky Vladimir 
Published: April 2011

ABSTRACTThe discovery of the new superconductor MgB2 with critical temperature of Tc = 39 K stimulated great activity in search for materials with higher Tc. Theoretical works predicted the possibility of obtaining such superconducting materials in other borides also, in particular in AgB2. It was predicted in these works that diborides of metals having the AlB2 type structure, among them AgB2 may have superconductivity with a Tc higher than 39 K. In an early very short report the lattice parameters of AgB2 were evaluated in a synthesized specimen. However, no other indication exists that AgB2 was ever produced. We report the preliminary results of our attempts to prepare AgB2 films.Thin films of Ag-B were produced by magnetron cosputtering in Ar ambient from two separate targets that of B and Ag on Si (100) substrates. The specimens were subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photo spectroscopy (XPS), Auger analysis and optical microscope (OM) investigations. Resistivity measurements in a wide temperature range were measured. No superconductivity was yet observed in the range ∼10 – 200. K on the basis of resistivity measurements. Preliminary results indicate that AgB2 might be an unstable phase.
Barium Strontium Titanate Ceramics Prepared by a Reaction-Sintering Process
Authors: Liou Yi-Cheng , Chen Jen-Hsien , Wu Chi-Ting 
Published: April 2011

ABSTRACTBarium strontium titanate (Ba0.7Sr0.3TiO3, BST) ceramics prepared by a reaction-sintering process were investigated. The mixture of raw materials of stoichiometric Ba0.7Sr0.3TiO3 was pressed and sintered into ceramics without any calcination stage involved. Perovskite BST ceramics were obtained after sintered at 1330–1370°C for 2–6 h. For 6 h soak time, a density value 5.68g/cm3 (99.8% of the theoretic value) was obtained at 1350°C sintering. Grains of sizes between 2μm and 15μm were formed after 1330–1370°C sintering for 2–6 h. A diffused ferroelectric-paraelectric transition was observed in pellets sintered at 1330°C for 2 h and disappeared at a longer soak time or a higher sintering temperature.
Preferential Crystallization of β-FeSi2 from Micro-droplets Generated by Laser Ablation.
Authors: Narazaki Aiko , Sato Tadatake , Kawaguchi Yoshizo , Niino Hiroyuki 
Published: April 2011

ABSTRACTβ-FeSi2 was successfully fabricated at room temperature via the deposition of molten micro-droplets generated by the KrF excimer laser ablation. Only the molten droplets precipitated as the β-FeSi2 crystalline phase on a silicon substrate kept even at room temperature, whereas the rest of film was amorphous. The crystallization behavior of micro-droplets has been discussed in the light of non-equilibrium process due to rapid cooling on the substrate. After the deposition, pulsed laser annealing was also performed in order to improve the crystallinity of the β-FeSi2 microprecipitates-containing film.
Structure-Property Relationships in Tb4PtGa12 and Y4PtGa12
Authors: Williams Willa M. , Lee Han-Oh , Moldovan Monica , Fisk Zachary , Young David P. , Chan Julia Y. 
Published: April 2011

AbstractSingle crystals of Y4PtGa12 have been synthesized and characterized by X-ray diffraction. The compound crystallizes in the cubic Im3m space group with lattice parameters a = 8.530(5) Å. Magnetic property measurements show that Y4PtGa12 does not order magnetically. Structure-property relationships with the isostructural antiferromagnet Tb4PtGa12 are discussed.
Pressure Tuning of Crystalline As2Te3
Authors: Scheidemantel T. J. , Meng J. F. , Badding J. V. 
Published: April 2011

ABSTRACTWe report the pressure dependence of the thermoelectric power of As2Te3. Pressures up to 10 GPa were induced using a Mao-Bell diamond anvil cell. The absolute value of the thermoelectric power dropped from S ≈ 230μV/K at ambient pressure to S ≈ 75 GPa near 5 GPa. At 6 GPa it then increased rapidly to S ≈ 220βV/K. This behavior is indicative of a structural phase transition as suggested by previously published high pressure phase diagrams.
On the Factors Governing the Refractive Indices of Inorganic Materials
Authors: Rocquefelte Xavier , Goubin Fabrice , Jobic Stéphane , Whangbo Myung-Hwan 
Published: April 2011

ABSTRACTThree key factors influencing the refractive indices of inorganic solid state materials were discussed on the basis of the concept of optical channels and the dielectric functions calculated for two series of closely related oxides. Implications of our observation concerning efficient UV blockers were discussed.
CHEMICAL AND PHYSICAL HARDNESS OF SOLIDS
Authors: Gilman John J. 
Published: April 2011

ABSTRACTThe concept of chemical hardness was originally developed as a measure of the stability of molecules. Its relationship to physical hardness and to solids is demonstrated here. Also, it is shown that shear moduli, and polarizabilitites, as well as band gaps are related to chemical hardness. Finally, evidence is presented that indentation hardness numbers are better measures of critical phase transition compressions than “pressure-cell” data.
Direct Femtosecond Inscription of Fiber Bragg Gratings.
Authors: Martinez Amós , Dubov Michael , Khrushchev Igor Y. , Bennion Ian 
Published: April 2011

ABSTRACTDirect, point-by-point inscription of fiber Bragg gratings by infrared femtosecond laser is reported. Using this technique, highly reflective gratings can be rapidly inscribed in standard, untreated fiber. Thermal studies demonstrate increased thermal stability compared to the UV-inscribed gratings.
Modifications and Color Markings in Glasses by UV Laser Radiation
Authors: Talkenberg M. , Falkenberg G. , Krauss M. , Kreutz E. W. 
Published: April 2011

ABSTRACTRare earth-, transition metal- and metal doped soda lime-, BK7- and photosensitive lithium aluminosilicate glass are irradiated by pulsed UV laser radiation (wavelength λL = 355nm, pulse length tp = 10 to 80 ns) as a function of repetition rate, pulse energy and overlap between successive pulses. The solid state laser radiation is focused into the volume to fluences below the removal-threshold. Depending on the chemical composition, the laser parameters, and the processing variables the laser radiation is absorbed by optically- and photochemically active polyvalent ions with conversion of the optical energy into fluorescence stimulation and ionization as well as color center formation resulting in modifications and/or color markings in the VIS. The absorption and concentration changes of the polyvalent ions are probed by optical spectroscopy and transient absorption spectroscopy. The photochemical and -physical processes such as oxidation and reduction of polyvalent ions and/or color center generation underlying the modifications and color markings are discussed.
Adsorption of DNA onto Charged Spheres
Authors: Hodrien Alison J. , Voice Alison M. , Waigh Thomas A. 
Published: April 2011

ABSTRACTThe complexation behaviour of linear DNA (negatively charged) with surface functionalised sub-micron latex spheres is studied by dynamic light scattering (DLS), small-angle neutron scattering (SANS), small-angle x-ray scattering (SAXS), and micro rheology. The complexes are measured in solution as a function of component concentration (CDNA, CSPH) and added salt concentration (Cs). In the absence of salt, measured radius increases with CDNA (CSPH held constant) up to a plateau value. The presence of salt causes a decrease in the measured complex radius, which may be due either to increased flexibility of the chains allowing them to form a more compact layer on the sphere surface, or dissociation of the two components due to screened electrostatics. More detailed experiments to determine this are underway.
Characterizations of enriched metallic single-walled carbon nanotubes in polymer composite
Authors: Chen Bin , Li Jing , Lu Yijiang , Cinke Martin , Au Dyng , Harmon Julie P. , Muisener Patrici Anne O. , Clayton LaNetra 
Published: April 2011

ABSTRACTWe characterize the electric properties of single-walled carbon nanotube (SWNT) dispersed in the polymethyl methacrylate (PMMA) composites. In the melt-blended sample, the SWNTs – originally semiconducting – became predominantly metallic. The interaction of the PMMA and SWNT is investigated by the polarized Raman studies. The structure changes in the PMMA and SWNT shows that the anisotropic interactions play important role in SWNT electronic density of states (DOS) changes. The increased metallic SWNT percentage is confirmed by the conductivity and dielectric constant measurements of composite and neat PMMA.
Perceptions of Nuclear Wastes across Extreme Time Perspectives
Authors: Drottz‐Sjöberg Britt‐Marie 
Published: April 2011

AbstractAn empirical study, financed by the Swedish Radiation Authority (SSI), on perception of time, time periods, and responsibilities related to the final repository for spent nuclear fuel was conducted in 2002. Citizens of the Oskarshamn and Östhammar municipalities (N=1,501) responded to a postal questionnaire regarding their participation in site‐specific investigations for the building of the Swedish repository, administered by the Swedish Nuclear Fuel and Waste Management Co (SKB). Approximately 41% of the sampled citizens responded to an eight‐page questionnaire, which included tasks of time estimates of specified historic events (e.g., when the first human landed on the moon, the development of Homo sapiens) and possible future events (e.g., a new glacial ice period, a radiation leakage from canisters in the repository). Some questions asked for risk estimations in relation to the repository, i.e., for oneself and for others in the community. Other questions inquired about perceptions of risks and responsibilities related to future generations. SSI was especially interested in the respondents' ratings of the importance of the authority's reviews of SKB's research programs for specified time periods, i.e., during operation, in a thousand years, ten thousand years, hundred thousand years, and up to a million years. The overall results showed rather restricted time horizons among the respondents. Risk estimations relating to nuclear wastes were not extremely high, and as usual the risk to others rated higher than the risk to oneself. Regarding the importance of SSI's review of SKB's research programs, people emphasized the importance of such reviews in the near future in contrast to the distant future, i.e., while under operation and up to 1,000 years, rather than for the longer time periods of relevance for the reviews. People also perceived the consequences to be much more severe in the shorter time perspectives than in the longer ones, given a leakage from the canisters in the repository. The importance of future generations' life situations was reported as high, and perceived to be of greater importance to oneself than to others. The construction of a safe final repository for spent nuclear fuel ranked the highest on a list of topics when respondents indicated the responsibilities of current generations. Ranked second and third were the items “to fight criminality” and “to give children and youth a good education.” The responsibility for depositing spent nuclear fuel in a reassuring manner was mainly attached to the entrepreneur, SKB, closely followed by the authorities (SSI and the Swedish Nuclear Safety Authority, SKI). The discussion focuses on the apparent paradox involving participants rather short time horizons, especially into the future, decreasing risk estimates across long time perspectives, and very high ratings regarding current generations' responsibilities for the life situations of future generations.
Public Involvement Designed to Circumvent Public Concern? The “Participatory Turn” in European Nuclear Activities
Authors: Sundqvist Göran , Elam Mark 
Published: April 2011

AbstractIn this paper we critically evaluate contemporary processes of public involvement in nuclear activities in Europe. Our focus is two collaborative “technology platforms” at the European level, one for implementing the geological disposal of nuclear waste, the other for rendering nuclear energy sustainable. In key documents and statements connected with the launching of these two platforms, public participation is assigned a vital role in their construction. While participation is presented in both cases as important for heightening the legitimacy of national nuclear industry programs and creating more room for public influence, the nature of this participation tends to remain obscure. From our analysis of the European Union documents and statements, informed by recent discussions in science and technology studies (STS), we conclude that “the participatory turn” in the nuclear sector focuses too strongly on procedural matters—on public involvement as a good in itself—while deflecting attention away from the possibilities of using participation as a more genuine means of enabling public issues and concerns to reach a higher level of articulation. Attempting to resolve legitimacy problems by conceiving of public participation as a way of maneuvering around public concerns is problematic since the latter must be more properly conceived as remaining the foundation for the former. If the issues calling for enlarged public participation in nuclear activities in Europe were awarded greater attention, then the legitimacy of these activities might indeed be improved. It can be imagined, for example, that the connections between the disposal of legacy wastes and the authorization of new build would be rendered more transparent.
Effects of the size and filler loading on the properties of copper‐ and silver‐nanoparticle‐filled epoxy composites
Authors: Chan K. L. , Mariatti M. , Lockman Z. , Sim L. C. 
Published: April 2011

AbstractCopper‐nanoparticle (CuNP)‐filled nanocomposites were prepared with various particle sizes and loadings. The nanocomposites incorporating 20‐nm CuNPs with 5 vol % loading displayed optimum properties as determined by electrical, mechanical, and thermal characterization. Silver nanoparticles (AgNPs) with a size of 20 nm were loaded into the epoxy resin to allow a comparison of the properties. Interestingly, at the percolation threshold, a 5 vol % loading of CuNP and AgNP nanocomposites resulted in slightly similar electrical conductivities of 0.01 and 0.02 S/cm, respectively. The CuNP and AgNP nanocomposites were also subjected to thermal aging at 150°C, and we observed that the electrical conductivity of both nanocomposites dropped only by about one order of magnitude after 8 weeks of exposure. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Improved properties of highly oriented graphene/polymer nanocomposites
Authors: Ren Peng‐Gang , Yan Ding‐Xiang , Chen Tao , Zeng Bao‐Qing , Li Zhong‐Ming 
Published: April 2011

AbstractA kind of molecular‐level dispersed and highly oriented graphene monolayer nanocomposite film was successfully obtained by in situ reduction of phenyl isocyanate functionalized graphite oxide (RPIGO) in N,N‐dimethylformamide in the presence of polystyrene (PS). Atomic force microscopy and transmission electron microscopy results show that the RPIGO monolayers were not only homogeneously intercalated into the PS matrix but also arranged parallel to the surface of the nanocomposite films. Because of the efficient interaction between the graphene monolayers and PS matrix, the mechanical properties of the graphene‐based nanocomposite films improved significantly. Compared with the pure PS film, a 28.4% increase in the Young's modulus and a 27.8% improvement in the tensile strength of the RPIGO–PS nanocomposites films were obtained with the addition of only 0.5 wt % graphite oxide. The glass‐transition temperature and onset degradation temperature of PS also increased from 96.6 and 427°C to 103.2 and 439°C, respectively. The improvement of the properties was mainly due to the large lateral thickness ratio and the high orientation of graphene monolayers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Electropolymerization of polypyrrole and polypyrrole‐ZnO nanocomposites on mild steel and its corrosion protection performance
Authors: Hosseini M. G. , Bagheri R. , Najjar R. 
Published: April 2011

AbstractPolypyrrole (PPy) and Polypyrrole‐ZnO (PPy‐ZnO) nanocomposites were electrodeposited on mild steel and its corrosion protection ability was studied by Tafel and Impedance techniques in 3.5% NaCl solution. Pure Polypyrrole film was not found to protect the mild steel perfectly but the coating with nano‐sized ZnO (PPy‐ZnO) has dramatically increased the corrosion resistance of mild steel. Electrochemical Impedance Spectroscopy (EIS) measurements indicated that the coating resistance (Rcoat) and corrosion resistance (Rcorr) values for the PPy‐ZnO nanocomposite coating was much higher than that of pure PPy coated electrode. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Relation of G1359A polymorphism of the cannabinoid receptor (CB1) gene with metabolic syndrome by ATP III classification
Authors: de Luis D. A. , Sagrado M. González , Aller R. , Izaola O. , Conde R. 
Published: April 2011

AbstractBackgroundA polymorphism (1359 G/A) of the cannabinoid type‐1 receptor gene was reported as a common polymorphism in Caucasian populations. Some metabolic disorders are related to this polymorphism.ObjectiveThe aim of our study was to investigate the association between metabolic syndrome and this polymorphism.DesignA population of 917 obese patients was analysed in a cross‐sectional survey. Bioimpedance, blood pressure, an assessment of nutritional intake and biochemical analysis were recorded.ResultsFive hundred and twelve patients (55.8%) had the genotype G1359G (wild‐type group), whereas 344 (37.5%) had genotype G1359A and 61 (6.7%) patients had A1359A. (G1359A and A1359A were included in the mutant‐type group; 44.2% total). In wild type patients, metabolic syndrome prevalence was higher (54.9% versus 45.1%; p < 0.05) than no metabolic syndrome prevalence. In patients with mutant genotypes, metabolic syndrome prevalence was lower (43.7% versus 56.3%; p < 0.05). Glucose, insulin and homeostasis model assessment levels were higher in patients with the wild genotype than in those with the mutant type. Adiponectin levels were lower in patients with the wild genotype than in those with the mutant type.ConclusionThe novel finding of this study is the association of the G1359A and A1359A cannabinoid type‐1 genotypes with a lower prevalence of metabolic syndrome than the G1359G genotype. Copyright © 2011 John Wiley & Sons, Ltd.