Effect of dental tissue conditioners and matrix metalloproteinase inhibitors on type I collagen microstructure analyzed by Fourier transform infrared spectroscopy

This study aimed to evaluate the chemical interaction of collagen with some substances usually applied in dental treatments to increase the durability of adhesive restorations to dentin. Initially, the similarity between human dentin collagen and type I collagen obtained from commercial bovine membranes of Achilles deep tendon was compared by the Attenuated Total Reflectance technique of Fourier Transform Infrared (ATR-FTIR) spectroscopy. Finally, the effects of application of 35% phosphoric acid, 0.1M ethylenediaminetetraacetic acid (EDTA), 2% chlorhexidine, and 6.5% proanthocyanidin solution on microstructure of collagen and in the integrity of its triple helix were also evaluated by ATR-FTIR. It was observed that the commercial type I collagen can be used as an efficient substitute for demineralized human dentin in studies that use spectroscopy analysis. The 35% phosphoric acid significantly altered the organic content of amides, proline and hydroxyproline of type I collagen. The surface treatment with 0.1M EDTA, 2% chlorhexidine, or 6.5% proanthocyanidin did not promote deleterious structural changes to the collagen triple helix. The application of 6.5% proanthocyanidin on collagen promoted hydrogen bond formation. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.

Near-infrared quantum cutting through a three-step energy transfer process in Nd3+-Yb3+ co-doped fluoroindogallate glasses

The Nd3+-Yb3+ couple was investigated in fluoroindogallate glasses using optical spectroscopy to elucidate the energy transfer mechanisms involved in the downconversion (DC) process. Upon excitation of a Nd3+ ion by an ultraviolet photon, DC through a three-step energy transfer process occurs, in which the energy of the ultraviolet photon absorbed by the Nd3+ ion is converted into three infrared photons emitted by Yb3+ ions, i.e. quantum cutting (QC). In addition, with excitation in the visible, our results confirm that the DC process occurs through a one-step energy transfer process, in which the energy of a visible photon absorbed by the Nd3+ ion is converted into only one infrared photon emitted by an Yb3+ ion. Time-resolved measurements enabled the estimation of the efficiencies of the cross-relaxation processes between Nd3+ and Yb3+ ions.

Isolation and characterization of sodium 2-fluoroacetate from Mascagnia rigida using chromatography and infrared spectroscopy

Sodium monofluoroacetate was first identified in Dichapetalum cymosum, a South African plant that can cause livestock poisoning and death. After, several other plants also showed to contain this toxin, which leads to the "sudden death". Mascagnia rigida, a well identified poisonous plant, commonly found in northeast of Brazil also cause sudden death in cattle, which shows clinical signs similar to those produced by the ingestion of plants that contain monofluoroacetate. Our aim was to identify the toxic compound present in the aqueous extract of M. rigida. For this purpose, the dried and milled plant was extracted; the extract was lyophilized and submitted to successive chromatographic process, until the desired purity of the active compound was achieved. The study of this material by planar chromatography and by infrared spectrometry indicated that the toxin can be a mixture of mono, di and trifluoroacetate. (C) 2012 Elsevier Ltd. All rights reserved.

VVV DR1: The first data release of the Milky Way bulge and southern plane from the near-infrared ESO public survey VISTA variables in the Via Lactea

Context. The ESO public survey VISTA variables in the Via Lactea (VVV) started in 2010. VVV targets 562 sq. deg in the Galactic bulge and an adjacent plane region and is expected to run for about five years. Aims. We describe the progress of the survey observations in the first observing season, the observing strategy, and quality of the data obtained. Methods. The observations are carried out on the 4-m VISTA telescope in the ZYJHK(s) filters. In addition to the multi-band imaging the variability monitoring campaign in the K-s filter has started. Data reduction is carried out using the pipeline at the Cambridge Astronomical Survey Unit. The photometric and astrometric calibration is performed via the numerous 2MASS sources observed in each pointing. Results. The first data release contains the aperture photometry and astrometric catalogues for 348 individual pointings in the ZYJHK(s) filters taken in the 2010 observing season. The typical image quality is similar to 0 ''.9-1 ''.0. The stringent photometric and image quality requirements of the survey are satisfied in 100% of the JHK(s) images in the disk area and 90% of the JHK(s) images in the bulge area. The completeness in the Z and Y images is 84% in the disk, and 40% in the bulge. The first season catalogues contain 1.28 x 10(8) stellar sources in the bulge and 1.68 x 10(8) in the disk area detected in at least one of the photometric bands. The combined, multi-band catalogues contain more than 1.63 x 10(8) stellar sources. About 10% of these are double detections because of overlapping adjacent pointings. These overlapping multiple detections are used to characterise the quality of the data. The images in the JHK(s) bands extend typically similar to 4 mag deeper than 2MASS. The magnitude limit and photometric quality depend strongly on crowding in the inner Galactic regions. The astrometry for K-s = 15-18 mag has rms similar to 35-175 mas. Conclusions. The VVV Survey data products offer a unique dataset to map the stellar populations in the Galactic bulge and the adjacent plane and provide an exciting new tool for the study of the structure, content, and star-formation history of our Galaxy, as well as for investigations of the newly discovered star clusters, star-forming regions in the disk, high proper motion stars, asteroids, planetary nebulae, and other interesting objects.

A Novel Method of Evaluating Ureteropelvic Junction Obstruction: Dynamic Near Infrared Fluorescence Imaging Compared to Standard Modalities to Assess Urinary Obstruction in a Swine Model

Purpose: Dynamic near infrared fluorescence imaging of the urinary tract provides a promising way to diagnose ureteropelvic junction obstruction. Initial studies demonstrated the ability to visualize urine flow and peristalsis in great detail. We analyzed the efficacy of near infrared imaging in evaluating ureteropelvic junction obstruction, renal involvement and the anatomical detail provided compared to conventional imaging modalities. Materials and Methods: Ten swine underwent partial or complete unilateral ureteral obstruction. Groups were survived for the short or the long term. Imaging was performed with mercaptoacetyltriglycine diuretic renogram, magnetic resonance urogram, excretory urogram, ultrasound and near infrared imaging. Scoring systems for ureteropelvic junction obstruction were developed for magnetic resonance urogram and near infrared imaging. Physicians and medical students graded ureteropelvic junction obstruction based on magnetic resonance urogram and near infrared imaging results. Results: Markers of vascular and urinary dynamics were quantitatively consistent among control renal units. The same markers were abnormal in obstructed renal units with significantly different times of renal phase peak, start of pelvic phase and start of renal uptake. Such parameters were consistent with those obtained with mercaptoacetyltriglycine diuretic renography. Near infrared imaging provided live imaging of urinary flow, which was helpful in identifying the area of obstruction for surgical planning. Physicians and medical students categorized the degree of obstruction appropriately for fluorescence imaging and magnetic resonance urogram. Conclusions: Near infrared imaging offers a feasible way to obtain live, dynamic images of urine flow and ureteral peristalsis. Qualitative and quantitative parameters were comparable to those of conventional imaging. Findings support fluorescence imaging as an accurate, easy to use method of diagnosing ureteropelvic junction obstruction.

Direct Determination of Sugar Cane Quality Parameters by X-ray Spectrometry and Multivariate Analysis

Current methods for quality control of sugar cane are performed in extracted juice using several methodologies, often requiring appreciable time and chemicals (eventually toxic), making the methods not green and expensive. The present study proposes the use of X-ray spectrometry together with chemometric methods as an innovative and alternative technique for determining sugar cane quality parameters, specifically sucrose concentration, POL, and fiber content. Measurements in stem, leaf, and juice were performed, and those applied directly in stem provided the best results. Prediction models for sugar cane stem determinations with a single 60 s irradiation using portable X-ray fluorescence equipment allows estimating the % sucrose, % fiber, and POL simultaneously. Average relative deviations in the prediction step of around 8% are acceptable if considering that field measurements were done. These results may indicate the best period to cut a particular crop as well as for evaluating the quality of sugar cane for the sugar and alcohol industries.

Single-wall carbon nanotube interactions with copper-oxamato building block of molecule-based magnets probed by resonance Raman spectroscopy

The electronic interactions between the [Cu(opba)]2- anions (where opba is orthophenylenebis (oxamato)) and single-wall carbon nanotubes (SWCNTs) were investigated by resonance Raman spectroscopy. The opba can form molecular magnets, and the interactions of opba with SWCNTs can produce materials with very different magnetic/electronic properties. It is observed that the electronic interaction shows a dependence on the SWCNT diameter independent of whether they are metallic or semiconducting, although the interaction is stronger for metallic tubes. The interaction also is dependent on the amount of complex that is probably adsorbed on the carbon surface of the SWCNTs. Some charge transfer can be also occurring between the metallic complex and the SWCNTs. Copyright (c) 2012 John Wiley & Sons, Ltd.

Solid electrolytes for electrochromic devices based on reversible metal electrodeposition

Air conditioning and lighting costs can be reduced substantially by changing the optical properties of "intelligent windows." The electrochromic devices studied to date have used copper as an additive. Copper, used here as an electrochromic material, was dissolved in an aqueous animal protein-derived gel electrolyte. This combination constitutes the electrochromic system for reversible electrodeposition. Cyclic voltammetry, chronoamperometric and chromogenic analyses indicated that were obtained good conditions of transparency (initial transmittance of 70%), optical reversibility, small potential window (2.1 V), variation of transmittance in visible light (63.6%) and near infrared (20%) spectral regions. Permanence in the darkened state was achieved by maintaining a lower pulse potential (-0.16 V) than the deposition potential (-1.0 V). Increasing the number of deposition and dissolution cycles favored the transmittance and photoelectrochemical reversibility of the device. The conductivity of the electrolyte (10(-3) S/cm) at several concentrations of CuCl2 was determined by electrochemical impedance spectroscopy. A thermogravimetric analysis confirmed the good thermal stability of the electrolyte, since the mass loss detected up to 100 degrees C corresponded to water evaporation and decomposition of the gel started only at 200 degrees C. Micrographic and small angle X-ray scattering analyses indicated the formation of a persistent deposit of copper particles on the ITO. (C) 2012 Elsevier B.V. All rights reserved.

Biosynthesis and uptake of copper nanoparticles by dead biomass of Hypocrea lixii isolated from the metal mine in the Brazilian Amazon Region

A biological system for the biosynthesis of nanoparticles (NPs) and uptake of copper from wastewater, using dead biomass of Hypocrea lixii was analyzed and described for the first time. The equilibrium and kinetics investigation of the biosorption of copper onto dead, dried and live biomass of fungus were performed as a function of initial metal concentration, pH, temperature, agitation and inoculum volume. The high biosorption capacity was observed for dead biomass, completed within 60 min of contact, at pH 5.0, temperature of 40 °C and agitation speed of 150 rpm with a maximum copper biosorption of 19.0 mg g(-1). The equilibrium data were better described using the Langmuir isotherm and kinetic analysis indicated that copper biosorption follows a pseudo-second-order model. The average size, morphology and location of NPs biosynthesized by the fungus were determined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). NPs were mainly spherical, with an average size of 24.5 nm, and were synthesized extracellularly. The X-ray diffraction (XRD) analysis confirms the presence of metallic copper particles. Infrared spectroscopy (FTIR) study revealed that the amide groups interact with the particles, which was accountable for the stability of NPs. This method further confirmed the presence of proteins as stabilizing and capping agents surrounding the copper NPs. These studies demonstrate that dead biomass of Hypocrea lixii provides an economic and technically feasible option for bioremediation of wastewater and is a potential candidate for industrial-scale production of copper NPs.

Interionic Interactions in Imidazolic Ionic Liquids Probed by Soft X-ray Absorption Spectroscopy

This work investigates pure ionic liquids (ILs) derived from an imidazolium ring with different carbonic chains and halides or bis(trifluoromethanesulfonilimide) (TFSI-) as anions, using X-ray absorption near edge spectroscopy (XANES) at different energies (N, S, O, F, and Cl edges) to probe the interionic interactions. XANES data show that the interaction with the anion is weaker when the cation is an imidazolium than when the salt is formed by smaller cations, as lithium, independently of the length of the carbonic chain attached to the imidazolium cation. The results also show that, for all studied as, it is not observed any influence of the anion on the XANES spectra of the cation, nor the opposite. 1-Methylimidazolium with Cl-, a small and strongly coordinating anion, presents in the N K XANES spectrum a splitting of the band corresponding to nitrogen in the imidazolic ring, indicating two different chemical environments. For this cation with TFSI-, on the contrary, this splitting was not observed, showing that the anion has a weaker interaction with the imidazolic ring, even without a lateral carbonic chain.

Interaction of chitosan and mucin in a biomembrane model environment

Chitosans have been widely exploited in biological applications, including drug delivery and tissue engineering, especially owing to their mucoadhesive properties, but the molecular-level mechanisms for the chitosan action are not known in detail. It is believed that chitosan could affect the mucus by interacting with the proteins mucins, in a process mediated by the cell membrane. In this study we used Langmuir monolayers of dimyristoylphosphatidic acid (DMPA) as simplified membrane models to investigate the interplay between the activity of mucins and chitosan. Surface pressure and surface potential measurements were performed with DMPA monolayers onto which chitosan and/or mucin was adsorbed. We found that the expanding effect from mucin was considerably reduced when chitosan was injected after mucin had been adsorbed on the DMPA monolayer. The results were consistent with the formation of complexes between mucin and chitosan, thus highlighting the importance of electrostatic interactions. Furthermore, chitosan could remove mucin that was co-deposited along with DMPA in Langmuir-Blodgett (LB) films, which could be ascribed to molecular-level interactions between chitosan and mucin inferred from the FTIR spectra of the LB films. In conclusion, the results with Langmuir and LB films suggest that electrostatic interactions are crucial for the mucoadhesive mechanism, which is affected by the complexation between chitosan and mucin. (C) 2012 Elsevier Inc. All rights reserved.

On the nu SiO infrared absorption of polysiloxane films

The infrared absorption of polysiloxanes involves a strong band at around 1050 cm(-1), attributed to the antisymmetric vibration of siloxane bridges. The splitting of this band into two components is generally attributed to coupling between next-neighbor siloxane groups along the polysiloxane chain. From a quantitative analysis of the spectra of these materials, we find that this splitting is larger when the material is in thin-film form, and that the relative intensity of the two components is polarization dependent. We show that these effects are fully understandable in the theoretical framework of infrared absorption by thin films, and are related to long-range dipolar interactions responsible for the longitudinal-transverse splitting effect in crystalline materials. As a consequence, the polarization dependence of the infrared absorption observed for thin films does not appear to be associated with an orientational ordering in the film. (c) 2012 Elsevier B.V. All rights reserved.

Femtosecond laser induced synthesis of Au nanoparticles mediated by chitosan

This paper reports the synthesis of Au nanoparticles by 30-fs pulses irradiation of a sample containing HAuCl4 and chitosan, a biopolymer used as reducing agent and stabilizer. We observed that it is a multi-photon induced process, with a threshold irradiance of 3.8 x 10(11) W/cm(2) at 790 nm. By transmission electron microscopy we observed nanoparticles from 8 to 50 nm with distinct shapes. Infrared spectroscopy indicated that the reduction of gold and consequent production of nanoparticles is related to the fs-pulse induced oxidation of hydroxyl to carbonyl groups in chitosan. (C) 2011 Optical Society of America

The young stellar cluster [DBS2003] 157 associated with the H ii region GAL 331.31-00.34

We report a study of the stellar content of the near-infrared (NIR) cluster [DBS2003] 157 embedded in the extended H ii region GAL 331.31-00.34, which is associated with the IRAS source 16085-5138. JHK photometry was carried out in order to identify potential ionizing candidates, and the follow-up NIR spectroscopy allowed the spectral classification of some sources, including two O-type stars. A combination of NIR photometry and spectroscopy data was used to obtain the distance of these two stars, with the method of spectroscopic parallax: IRS 298 (O6 V, 3.35 +/- 0.61 kpc) and IRS 339 (O9 V, 3.24 +/- 0.56 kpc). Adopting the average distance of 3.29 +/- 0.58 kpc and comparing the Lyman continuum luminosity of these stars with that required to account for the radio continuum flux of the H ii region, we conclude that these two stars are the ionizing sources of GAL 331.31-00.34. Young stellar objects (YSOs) were searched by using our NIR photometry and mid-infrared (MIR) data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) survey. The analysis of NIR and MIR colourcolour diagrams resulted in 47 YSO candidates. The GLIMPSE counterpart of IRAS 16085-5138, which presents IRAS colour indices compatible with an ultracompact H ii region, has been identified. The analysis of its spectral energy distribution between 2 and m revealed that this source shows a spectral index a= 3.6 between 2 and m, which is typical of a YSO immersed in a protostellar envelope. Lower limits to the bolometric luminosity and the mass of the embedded protostar have been estimated as L= 7.7 x 10(3) L? and M= 10 M?, respectively, which correspond to a B0B1 V zero-age main sequence star.

Characterisation of young stellar clusters

Aims. Several embedded clusters are found in the Galaxy. Depending on the formation scenario, most of them can evolve to unbounded groups that are dissolved within 10 Myr to 20 Myr. A systematic study of young stellar clusters that show distinct characteristics provides interesting information on the evolutionary phases during the pre-main sequence. To identify and to understand these phases we performed a comparative study of 21 young stellar clusters. Methods. Near-infrared data from 2MASS were used to determine the structural and fundamental parameters based on surface stellar density maps, radial density profile, and colour-magnitude diagrams. The cluster members were selected according to their membership probability, which is based on the statistical comparison with the cluster proper motion. Additional members were selected on the basis of a decontamination procedure that was adopted to distinguish field stars found in the direction of the cluster area. Results. We obtained age and mass distributions by comparing pre-main sequence models with the position of cluster members in the colour-magnitude diagram. The mean age of our sample is similar to 5 Myr, where 57% of the objects is found in the 4-10 Myr range of age, while 43% is <4 Myr old. Their low E(B - V) indicate that the members are not suffering high extinction (AV <1 mag), which means they are more likely young stellar groups than embedded clusters. Relations between structural and fundamental parameters were used to verify differences and similarities that could be found among the clusters. The parameters of most of the objects show the same trends or correlations. Comparisons with other young clusters show similar relations among mass, radius, and density. Our sample tends to have larger radius and lower volumetric density than embedded clusters. These differences are compatible with the mean age of our sample, which we consider intermediate between the embedded and the exposed phases of the stellar clusters evolution.