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Wollastonite-poly( n-butyl-2-cyanoacrylate) composite (W-BCA) has been proposed to immobilize anatomically bone fragments in order to achieve an optimal healing process. The present study evaluated the in vitro and in vivo behavior of three types of fillers: powdered natural wollastonite (Wn), synthetic pseudowollastonite powder (Ws), and synthetic pseudowollastonite powder coated with 5% acetyl tributyl citrate (Wst). The Wst-BCA composite underwent a higher degradability in the real-time degradation test and a superior cytotoxic effect; whereas the Wn-BCA composite showed a higher degradability in the accelerated test with no cytotoxicity. The formation of an extracellular collagenous matrix deposit on its surface and the most favorable new bone formation on Wn-BCA indicate its potential for bone adhesive use in unstable orthopedic traumas. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1121-1129, 2014. [ABSTRACT FROM AUTHOR]

In this work, a porous and homogeneous titanium dioxide layer was grown on commercially pure titanium substrate using a micro-arc oxidation (MAO) process and Ca-P-based electrolyte. The structure and morphology of the TiO coatings were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, and profilometry. The chemical properties were studied using electron dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy. The wettability of the coating was evaluated using contact angle measurements. During the MAO process, Ca and P ions were incorporated into the oxide layer. The TiO coating was composed of a mixture of crystalline and amorphous structures. The crystalline part of the sample consisted of a major anatase phase and a minor rutile phase. A cross-sectional image of the coating-substrate interface reveals the presence of voids elongated along the interface. An osteoblast culture was performed to verify the cytocompatibility of the anodized surface. The results of the cytotoxicity tests show satisfactory cell viability of the titanium dioxide films produced in this study. [ABSTRACT FROM AUTHOR]

A combination of first-principles calculations based on density-functional theory, pseudopotentials, and x-ray photoelectron spectroscopy (XPS) measurements is used in order to study Au segregation in Cu3Au(111) surfaces. Our theoretical results suggest Au compositions from 50% to 75% in the topmost layer, depending on the chemical potentials of the atomic species. This strong Au segregation is restricted to the topmost surface plane and it is supported by the XPS measurements in a semiquantitative manner. [ABSTRACT FROM AUTHOR]

Quality control of fuel-related properties of biodiesel, such as thermal stability, is needed to obtain consistent engine performance by fuel users, since biodiesel is susceptible to auto-oxidation when exposed to air, light, and temperature during storage. In this work two pure standard reference materials of biodiesels produced from soy oil and animal feedstocks were studied. Differential scanning calorimetry and thermogravimetry measurements were performed and the analysis of the results revealed small temperature variations in the thermal events among the two standards, these differences are due mainly to their chemical composition, been highly influenced by the amounts of unsaturated esters. [ABSTRACT FROM AUTHOR]

Simultaneous crystal structure, microstructure, and morphology modeling with convolution-based profile fitting of angle-dispersive synchrotron x-ray diffraction data was applied to retrieve the size-dependent lattice changes in nanocrystalline rutile TiO2. The dominant prismatic crystallite morphology was adequately modeled using the parallelepiped geometry. As with anatase TiO2, opposing trends of decreasing c and increasing a parameter, as well as lattice expansion with decreasing average crystallite size were observed. A correlation between Ti vacancy abundance and lattice volume increase suggests a possible causative link. [ABSTRACT FROM AUTHOR]

Abstract: We construct a model to obtain the density of point defects in N-layer graphene by combining Raman spectroscopy and the TRIM (Transport Range of Ions in Matter) simulation package. The model relates the intensity (or area) ratio of graphene’s D and G bands to the defect density on each layer due to Ar+ bombardment. Our method is effective for ion fluences ranging from 1011 to ∼1014 Ar+/cm−2 and it should be in principle extendable to any kind of ion and energy. [Copyright &y& Elsevier]

Highlights: [•] Experimental spectra of biodiesel are fit based on theoretical calculations. [•] The biodiesel ester composition can be determined using Raman spectroscopy. [•] We derived a protocol to be used for determining the bio-origin of biodiesels. [ABSTRACT FROM AUTHOR]

Quick setting cements may be a promising alternative to metallic devices for immobilization of bone fragments in several maxillofacial surgical procedures. The aim of this study was the evaluation of bioactivity and degradation of wollastonite-poly(n-butyl-2-cyanoacrylate) composite biomaterials, just to be used as surgical cements. Three formulations were prepared by mixing n-butyl-2-cyanoacrylate with natural wollastonite W, silanized wollastonite-Ws and wollastonite, coated with 5 % acetyl tributyl citrate-Wa. Raw materials and composites were characterized by means of X-ray diffraction, Fourier transform-infrared spectroscopy, thermal gravimetric analysis and scanning electron microscopy, coupled to energy dispersive X-ray analysis. Bioactivity was tested by immersion of the material into simulated body fluid (SBF) for 21. Hydrolytic degradation was studied in distilled water at 70 °C for 2, 7 and 30. The morphological and compositional analysis of material surfaces after SBF immersion tests showed a time dependent apatite nucleation and growth, typical of bioactive materials. The apatite layer formed on Wa-BCA after 21 of soaking in SBF was denser than those on W-BCA and Ws-BCA composites. The greater degradation observed for the Wa-BCA composite and the subsequent exposition of bioactive ceramics to the environment seems to be the reason for the increased bioactivity, in comparison to the other formulations tested behavior makes these biomateriales attractive to be used as bone cements. [ABSTRACT FROM AUTHOR]

Abstract: Bovine serum albumin (BSA) may have an inhibitory or promoter effect on hydroxyapatite (HA) nucleation when apatite is precipitated in a medium containing the protein. In this study we evaluated the influence of BSA on the precipitation of calcium phosphate phases (CP) from simulated body fluid (SBF) when the protein was previously bounded to HA surface. The kinetics of BSA immobilization onto hydroxyapatite surface was performed in different buffers and protein concentrations in order to adjust experimental conditions in which BSA was tightly linked to HA surface for long periods in SBF solution. It was shown that for BSA concentration higher than 0.1mg/mL the adsorption to HA surface followed Langmuir–Freundlich mechanisms, which confirmed the existence of cooperative protein–protein interactions on HA surface. Fourier Transformed Infrared Attenuated Total Reflectance Microscopy (FTIRM-ATR) evidenced changes in BSA conformational state in favor of less-ordered structure. Analyses from high resolution grazing incident X-ray diffraction using synchrotron radiation (GIXRD), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) showed that a poorly crystalline calcium phosphate was precipitated on the surface of HA discs coated with BSA, after the immersion in SBF for 4 days. The new bioactive layer had morphological characteristics similar to the one formed on the HA surface without protein. It was identified as a carbonated apatite with preferential crystal growth along apatite 002 direction. The GIXRD results also revealed that BSA layer bound to the surface inhibited the HA dissolution leading to a reduction on the formation of new calcium phosphate phase. [Copyright &y& Elsevier]

Abstract: We investigate the stability of tris-(8-hydroxyquinolinato) aluminum (Alq3) under UV photo degradation using a combination of experimental and theoretical techniques. Alq3 thin films were irradiated with He–Xe lamp discharges, as a function of the exposition time, at a wavelength λ =307nm. The irradiated and non-irradiated films were analyzed by Fourier transform infrared (FTIR) spectroscopy. The experimental FTIR spectrum of the exposed sample exhibits a band at 1697cm−1, attributed to a carbonyl group. Theoretical calculations of Gibbs free energy and molecular vibrational properties for a variety of possible degradation products allow us to determine the most likely products and produce insight into the degradation mechanisms. [Copyright &y& Elsevier]

Abstract: The goal of this work is to prepare well-ordered molybdenum oxide films using oxygen implanted Cu3Au(100) substrate (CAOS, Cu3Au–Oxygen Substrate) and identify the structure of the different oxide phases. Those films were grown on an UHV chamber (2×10−10 mbar background pressure) and prepared by electron beam deposition. The structure of the films was studied using low energy electron diffraction (LEED), scanning tunnelling microscopy (STM), and X-ray photoelectron spectroscopy (XPS). The ultra thin molybdenum film shows the formation of an oxide layer with hexagonal symmetry plus a square lattice. The hexagonal mesh units are rotated by 90° (or 30°) with respect to one another. Based on XPS data, the Mo cations are in an oxidation state that ranges from 4+ to 6+. STM results show the presence of hexagonal islands formed over a square symmetry phase. [Copyright &y& Elsevier]

Non-planar Fin Field Effect Transistors (FinFET) are already present in modern devices. The evolution from the well-established 2D planar technology to the design of 3D nanostructures rose new fabrication processes, but a technique capable of full characterization, particularly their dopant distribution, in a representative (high statistics) way is still lacking. Here we propose a methodology based on Medium Energy Ion Scattering (MEIS) to address this query, allowing structural and compositional quantification of advanced 3D FinFET devices with nanometer spatial resolution. When ions are backscattered, their energy losses unfold the chemistry of the different 3D compounds present in the structure. The FinFET periodicity generates oscillatory features as a function of backscattered ion energy and, in fact, these features allow a complete description of the device dimensions. Additionally, each measurement is performed over more than thousand structures, being highly representative in a statistical meaning. Finally, independent measurements using electron microscopy corroborate the proposed methodology. [ABSTRACT FROM AUTHOR]

Squeezing optical fields into nanometer scale is the key step to perform spatially resolved near‐field optics. In scattering‐type near‐field optical microscopy, this task is accomplished by nanoantennas that convert propagating radiation to local near‐fields and vice versa. The usual nanoantenna is composed by an elongated metal structure whose longitudinal dimension is scaled to support dipole modes of localized surface plasmon resonances. However, monopole modes can also be explored if the elongated metal nanoparticle is electrically grounded on a flat metallic plateau that acts like a mirror providing the monopole's image that closes the dipole system. Here, a method for batch production of monopole nanoantennas for scattering‐type near‐field scanning optical microscopy is presented. The nanoantennas are composed of a micropyramidal body with a nanopyramidal end whose lateral dimension can be scaled to fine‐tune localized surface plasmon resonance modes. The monopole character of the nanoantennas is revealed by electron energy loss spectroscopy, and their efficiency and reproducibility are tested in tip‐enhanced Raman spectroscopy experiments performed on single‐layer graphene and single‐walled carbon nanotubes. Monopole nanoantennas composed of micropyramidal bodies with nanopyramidal ends are used as probes for scattering‐type near‐field scanning optical microscopy (NSOM). The monopole character of the nanoantennas is revealed by highly‐resolved electron energy and the length of the nanopyramid tip can be scaled to fine‐tune localized surface plasmon resonances, giving rise to extremely high local field enhancement factors. [ABSTRACT FROM AUTHOR]

Plasmon-tunable tip pyramids (PTTPs) are reproducible and efficient nanoantennas for tip-enhanced Raman spectroscopy (TERS). Their fabrication method is based on template stripping of a segmented gold pyramid with a size-adjustable nanopyramid end, which is capable of supporting monopole localized surface plasmon resonance (LSPR) modes leading to high spectral enhancement when its resonance energy is matched with the excitation laser energy. Here, we describe in detail the PTTP fabrication method and report a statistical analysis based on 530 PTTPs' and 185 ordinary gold micropyramids' templates. Our results indicate that the PTTP method generates probes with an apex diameter smaller than 30 nm on 92.4% of the batch, which is a parameter directly related to the achievable TERS spatial resolution. Moreover, the PTTPs' nanopyramid edge size L, a critical parameter for LSPR spectral tuning, shows variability typically smaller than 12.5%. The PTTP's performance was tested in TERS experiments performed on graphene, and the results show a spectral enhancement of up to 72-fold, which is at least one order of magnitude higher than that typically achieved with gold micropyramids. Imaging resolution is in the order of 20 nm.