Synthesis, Infrared Spectroscopy and Crystal Structure Determination of a New Decavanadate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Solution infrared spectroscopy investigation of copper (II) azide-complexes.

The structure of the two azide-complexes, [Cu(N-3)(2)(N,N-diEten)](2) and [Cu(N-3)(2)(tmeen)](2), N,N-diEten=N,N-diethylethylenediamine; tmeen=N,N,N',N'-tetramethyethylenediamine in solutions of acetonitrile, acetone, tetrahydrofuran, chloroform and dichloromethane, were investigated by infrared spectroscopy. The data show that the complex [Cu(N-3)(2)(N,N-diEten)](2) mantains its structure in solution, while that for [Cu(N-3)(2)(tmeen)](2) is modified.

Morphology of alumina: a comparison between infrared spectroscopy and X-ray diffractometry

Morphology of three samples of alumina are investigated. Infrared spectra are analysed by use of their morphology through the theory of average dielectric constant. Crystal shape is obtained from X-ray diffraction patterns by reflection intensity ratio. In the case of electron scanning microscopy, shape factor was obtained by an average axial ratio of the particles. Comparison of results show that there is agreement among these techniques and infrared spectra can be used to determine the morphology of alumina particles from 2.7 to 10 mu m, even for heterogeneous samples. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Effects of a single near-infrared laser treatment on cutaneous wound healing: Biometrical and histological study in rats

Background: Low intensity laser therapy has been recommended to support the cutaneous repair; however, so far studies do not have evaluated the tissue response following a single laser treatment. This study investigated the effect of a single laser irradiation on the healing of full-thickness skin lesions in rats.Methods: Forty-eight male rats were randomly divided into three groups. One surgical lesion was created on the back of rats using a punch of 8 mm in diameter. One group was not submitted to any treatment after surgery and it was used as control. Two energy doses from an 830-nm near-infrared diode laser were used immediately post-wounding: 1.3 J cm(-2) and 3 J cm(-2). The laser intensity 53 mW cm(-2) was kept for both groups. Biometrical and histological analyses were accomplished at days 3, 7 and 14 post-wounding.Results: Irradiated lesions presented a more advanced healing process than control group. The dose of 1.3 J cm(-2) leaded to better results. Lesions of the group irradiated with 1.3 J cm(-2) presented faster lesion contraction showing quicker re-epithelization and reformed connective tissue with more organized collagen fibers.Conclusions: Low-intensity laser therapy may accelerate cutaneous wound healing in a rat model even if a single laser treatment is performed. This finding might broaden current treatment regimens. (c) 2007 Elsevier B.V. All rights reserved.

Infrared and far-infrared spectroscopy of (CH3OH)-C-13: TeraHertz laser lines and assignments

We use a (CO2)-C-13 laser as optical pumping source to search for new THz laser lines generated from (CH3OH)-C-13. Nineteen new THz laser lines (also identified as far-infrared, FIR) ranging from 42.3 mu m (7.1 THz) to 717.7 mu m (0.42 THz) are reported. They are characterized in wavelength, offset, relative polarization, relative intensity, and optimum working pressure. We have assigned eight laser lines to specific rotational energy levels in the excited state associated with the C-O stretching mode. (c) 2006 Elsevier B.V. All rights reserved.

Local structure and near-infrared emission features of neodymium-based amine functionalized organic/inorganic hybrids

Nd3+-based organic/inorganic hybrids have potential application in the field of integrated optics. Attractive sol-gel derived di-urea and di-urethane cross-linked poly (oxyethylene) (POE)/siloxane hybrids (di-ureasils and di-urethanesils, respectively) doped with neodymium triflate (Nd(CF3SO3)(3)) were examined by Fourier transform mid-infrared (FT-IR), Raman (FT-Raman), Si-29 magic-angle spinning (MAS) nuclear magnetic resonance (NMR) and photoluminescence spectroscopies, and small-angle X-ray scattering (SAXS). The goals of this work were to determine which cation coordinating site of the host matrix (ether oxygen atoms or carbonyl oxygen atoms) is active in each of the materials analyzed, its influence on the nanostructure of the samples and its relation with the photoluminescence properties. The main conclusion derived from this study is that the hydrogen-bonded associations formed throughout the materials play a major role in the hybrids nanostructure and photoluminescence properties.

Near-infrared Kerr nonlinearity of Pb(PO3)(2)-WO3 glasses

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Nonresonant third-order nonlinear properties of NaPO3-WO3-Bi2O3 glasses in the near infrared

nonlinear (NL) refractive index, n(2), of NaPO3-WO3-Bi2O3 glass with different relative amounts of the constituents was measured at 1064 and 800 nm using the Z-scan and the thermally managed eclipse Z-scan techniques, respectively. The values of n(2) >= 10(-15) cm(2)/W and negligible NL absorption coefficient were determined. The large values of the NL refractive index and the very small NL absorption indicate that these materials have large potential for all-optical switching applications. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3212972]

Near-infrared third-order nonlinearity of PbO-GeO(2) films containing Cu and Cu(2)O nanoparticles

We report measurements of the nonlinear (NL) refractive index n(2) of lead-germanium films (LGFs) containing Cu and Cu(2)O nanoparticles (NPs). The thermally managed eclipse Z-scan technique with 150 fs pulses from a laser operating at 800 nm was used. The NL refractive index measured, n(2)=6.3x10(-12) cm(2)/W has electronic origin and the NL absorption coefficient alpha(2) is smaller than 660 cm/GW. The figure of merit n(2)/lambda alpha(2) is enhanced by more than two orders of magnitude in comparison with the result for the LGFs without the copper based NPs. (C) 2008 American Institute of Physics.

Upconversion luminescence in Er3+ doped Ga10Ge 25S65 glass and glass-ceramic excited in the near-infrared

The infrared-to-visible frequency upconversion was investigated in Er 3+-doped Ga10Ge25S65 glass and in the transparent glass-ceramic obtained by heat-treatment of the glass above its glass-transition temperature. Continuous-wave and pulsed lasers operating at 980 nm and 1480 nm were used as excitation sources. The green (2H 11/2 → 4I15/2; 4S3/2 → 4I15/2) and red (4F9/2 → 4I15/2) photoluminescence (PL) signals due to the Er3+ ions were characterized. The PL decay times were influenced by energy transfer among Er3+ ions, by cross-relaxation processes and by energy transfer from the Er3+ ions to the host material. The PL from the Er3+ ions hosted in the crystalline phase was distinguished only when the glass-ceramic was excited by the 1480 nm pulsed laser. The excitation pathways responsible for the green and red PL bands are discussed to explain the differences between the spectra observed under continuous-wave and pulsed excitation. © 2013 American Institute of Physics.

Infrared to visible up-conversion emission in Er3+/Yb 3+ codoped fluoro-phosphate glass-ceramics

Erbium Er3+ and ytterbium Yb3+ codoped fluoro-phosphate glasses belonging to the system NaPO3-YF 3-BaF2-CaF2 have been prepared by the classical melt-quenching technique. Glasses containing up to 10 wt% of erbium and ytterbium fluorides have been obtained and characterized using differential scanning calorimetry (DSC) and UV-visible and near-infrared spectroscopy. Transparent and homogeneous glass-ceramics have been then reproducibly synthetized by appropriate heat treatment above glass transition temperature of a selected parent glass. Structural investigations of the crystallization performed through X-ray diffractometry (XRD) and scanning electron microscopy (SEM) have evidenced the formation of fluorite-type cubic crystals based during the devitrification process. Finally, infrared to visible up-conversion emission upon excitation at 975 nm has been studied on the Er3+ and Yb 3+ codoped glass-ceramics as a function of thermal treatment time. A large enhancement of intensity of the up-conversion emissions-about 150 times- has been observed in the glass-ceramics if compared to the parent glass one, suggesting an incorporation of the rare-earth ions (REI) into the crystalline phase. © 2012 The American Ceramic Society.

Near-infrared nonlinearity of a multicomponent tellurium oxide glass at 800 and 1,064 nm

We report on the nonlinear (NL) optical properties of glassy TeO2-GeO2-K2O-Bi2O3 at lambda = 800 nm and lambda = 1,064 nm. Using the Kerr gate technique with a laser delivering 150 fs pulses at 800 nm, we demonstrated the fast NL response of the samples. The modulus of the NL refractive index, n (2), at 800 nm was similar to 10(-15) cm(2)/W. The Z-scan technique was used to determine n (2) a parts per thousand +10(-15) cm(2)/W, at 1,064 nm with pulses of 17 ps. The two-photon absorption coefficient, alpha (2), was smaller than the minimum that we can measure (< 0.003 cm/GW). The figure of merit n (2)/alpha (2) lambda was calculated and indicates that this glass composition has large potential to be used for all-optical switching.

Flame retardant properties of the bark powder of Anadenanthera peregrina var. falcata (Benth.) Altschul (angico) studied by coupled thermogravimetry-Fourier transform infrared spectroscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Encapsulation of paclitaxel into a bio-nanocomposite. a study combining inelastic neutron scattering to thermal analysis and infrared spectroscopy

The anticancer drug paclitaxel was encapsulated into a bio-nanocomposite formed by magnetic nanoparticles, chitosan and apatite. The aim of this drug carrier is to provide a new perspective against breast cancer. The dynamics of the pure and encapsulated drug were investigated in order to verify possible molecular changes caused by the encapsulation, as well as to follow which interactions may occur between paclitaxel and the composite. Fourier transformed infrared spectroscopy, thermal analysis, inelastic and quasi-elastic neutron scattering experiments were performed. These very preliminary results suggest the successful encapsulation of the drug.