FTIR analysis of water in supercritical carbon dioxide microemulsions using monofunctional perfluoropolyether surfactants

We describe perfluoropolyether (PFPE) surfactants which are capable of stabilising the water/CO2 interface and present FTIR spectroscopic evidence for the formation of water in supercritical carbon dioxide microemulsions. A wide variety of single chain surfactants of differing chain lengths but similar structure has been screened and the effect of the surfactant chain length on the water uptake was studied. The ammonium carboxylate of the PFPE surfactant Krytox FSL(TM) with an average molecular weight of 2500 g mol(-1) was demonstrated to be the surfactant capable of dissolving the most water out of all the tested surfactants and hence to have the optimum chain length. (C) 2002 Elsevier Science B.V. All rights reserved.

Peak Separation by Derivative Spectroscopy Applied to FTIR Analysis of Hydrolized Silica

Reliable spectral analysis is only achieved if the spectrum is thoroughly investigated in regard to all hidden and overlapped peaks. This paper describes the steps undertaken to find and separate such peaks in the range of 3000 to 4000 cm(-1) in the case of three different infrared absorption spectra of the glass surface of hydrolyzed silica optical fibers. Peak finding was done by the analysis of the second and fourth derivatives of the digital data, coupled with the available knowledge of infrared spectroscopy of silica-water interaction in the investigated range. Peak separation was accomplished by curve fitting with four different models. The model with the best fit was described by a sum of pure Gaussian peaks. Shoulder limit and detection limit maps were used to validate the revealed spectral features.

Degree of conversion of polymer-matrix composite assessed by FTIR analysis

Aims and objectives: The behavior of polymer-matrix composite is dependent on the degree of conversion. The aim of this study was to evaluate the degree of conversion of two resin cements following storage at 37°C immediately, 24 and 48 hours, and 7 days after light-curing by FTIR analysis. Materials and methods: The specimens were made in a metallic mold and cured with blue LED with power density of 500 mW/cm2 for 30 seconds. The specimens were pulverized, pressed with KBr and analyzed with FTIR following storage times. Statistical analysis used: ANOVA (two-way) and Tukey's post hoc. Results: To the polymer-matrix composites between 24 and 48 hours does not show a significant increase (p > 0.05), however, the highest values were found after 7 days. Conclusion: The polymer-matrix composites used in this study showed similarity on the degree of conversion and increased of according to the time of storage.

Comparative Analysis of Azo Dye Biodegradation by Aspergillus oryzae and Phanerochaete chrysosporium

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparative Study of Four Portuguese 16th Century Illuminated Manueline Charters based on Spectroscopy and Chemometrics Analysis

The comparative study based on spectroscopic analysis of the materials used to produce four sixteenth-century Manueline Charters (the Charters of Alcochete, Terena, Alandroal and Evora) was performed following a systematic analytical approach. SEM–EDS, l-Raman and l-FTIR analysis highlighted interesting features between them, namely the use of different pigments and colourants (such as different green and yellow pigments), the presence of pigments alterations and the use of a non-expected extemporaneous material (with the presence of titanium white in the Charter of Alcochete). Principal component analysis restricted to the C–H absorption region (3000–2840 cm-1) was applied to 36 infrared spectra of blue historical samples from the Charters of Alcochete,Terena, Alandroal and Évora, suggesting the use of a mixture of a triglyceride and polysaccharide as binder.

High performance additive manufactured scaffolds for bone tissue engineering application

This study demonstrates the feasibility of additive manufactured poly(3-caprolactone)/silanized tricalcium phosphate (PCL/TCP(Si)) scaffolds coated with carbonated hydroxyapatite (CHA)-gelatin composite for bone tissue engineering. In order to reinforce PCL/TCP scaffolds to match the mechanical properties of cancellous bone, TCP has been modified with 3-glycidoxypropyl trimethoxysilane (GPTMS) and incorporated into PCL to synthesize a PCL/TCP(Si) composite. The successful modification is confirmed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis. Additive manufactured PCL/TCP(Si) scaffolds have been fabricated using a screw extrusion system (SES). Compression testing demonstrates that both the compressive modulus and compressive yield strength of the developed PCL/TCP(Si) scaffolds fall within the lower ranges of mechanical properties for cancellous bone, with a compressive modulus and compressive yield strength of 6.0 times and 2.3 times of those of PCL/TCP scaffolds, respectively. To enhance the osteoconductive property of the developed PCL/TCP(Si) scaffolds, a CHA-gelatin composite has been coated onto the scaffolds via a biomimetic co-precipitation process, which is verified by using scanning electron microscopy (SEM) and XPS. Confocal laser microscopy and SEM images reveal a most uniform distribution of porcine bone marrow stromal cells (BMSCs) and cellsheet accumulation on the CHA-gelatin composite coated PCL/TCP(Si) scaffolds. The proliferation rate of BMSCs on the CHA-gelatin composite coated PCL/TCP(Si) scaffolds is 2.0 and 1.4 times higher compared to PCL/TCP(Si) and CHA coated PCL/TCP(Si) scaffolds, respectively, by day 10. Furthermore, the reverse transcription polymerase chain reaction (RT-PCR) and western blot analyses reveal that CHA-gelatin composite coated PCL/TCP(Si) scaffolds stimulate osteogenic differentiation of BMSCs the most compared to the other scaffolds. In vitro results of SEM, confocal microscopy and proliferation rate also show that there is no detrimental effect of GPTMS modification on biocompatibility of the scaffolds.

The undesirable acetylation of cellulose by the acetate ion of 1-ethyl-3-methylimidazolium acetate

The ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim]OAc) is considered to be an inert solvent of cellulose and lignocellulosic biomass. Acetylation (1.7 % mol, or DS 0.017) of cellulose after dissolution in [C2mim]OAc (150 °C for 20 min), is demonstrated by compositional analysis, FTIR analysis and 13C NMR spectroscopy (in [C2min]OAc with 13C enriched acetate). This acetylation, in the absence of added acylating agents, has not been reported before and may limit [C2mim]OAc utility in industrial scale biomass processing, even at this low extent. For example, cellulose acetylation may contribute to IL loss in processes where the IL is recovered and reused and inhibit enzyme saccharification of cellulose in lignocellulosic biofuel production processes based on saccharification and fermentation.

Fabrication and characterization of RF plasma polymerized thin films from 3,7-dimethyl-1,6-octadien-3-ol for electronic and biomaterial applications

Poly(linalool) thin films were fabricated using RF plasma polymerisation. All films were found to be smooth, defect-free surfaces with average roughness of 0.44 nm. The FTIR analysis of the polymer showed a notable reduction in –OH moiety and complete dissociation of C=C unsaturation compared to the monomer, and presence of a ketone band absent from the spectrum of the monomer. Poly(linalool) were characterised by chain branching and a large quantity of short polymer chains. Films were optically transparent, with refractive index and extinction coefficient of 1.55 and 0.001 (at 500 nm) respectively, indicating a potential application as an encapsulating (protective) coating for circuit boards. The optical band gap was calculated to be 2.82 eV, which is in the semiconducting energy gap region.

Development of salinity tolerance in rice by constitutive-overexpression of genes involved in the regulation of programmed cell death

Environmental factors contribute to over 70% of crop yield losses worldwide. Of these drought and salinity are the most significant causes of crop yield reduction. Rice is an important staple crop that feeds more than half of the world’s population. However among the agronomically important cereals rice is the most sensitive to salinity. In the present study we show that exogenous expression of anti-apoptotic genes from diverse origins, AtBAG4 (Arabidopsis), Hsp70 (Citrus tristeza virus) and p35 (Baculovirus), significantly improves salinity tolerance in rice at the whole plant level. Physiological, biochemical and agronomical analyses of transgenic rice expressing each of the anti-apoptotic genes subjected to salinity treatment demonstrated traits associated with tolerant varieties including, improved photosynthesis, membrane integrity, ion and ROS maintenance systems, growth rate, and yield components. Moreover, FTIR analysis showed that the chemical composition of salinity-treated transgenic plants is reminiscent of non-treated, unstressed controls. In contrast, wild type and vector control plants displayed hallmark features of stress, including pectin degradation upon subjection to salinity treatment. Interestingly, despite their diverse origins, transgenic plants expressing the anti-apoptotic genes assessed in this study displayed similar physiological and biochemical characteristics during salinity treatment thus providing further evidence that cell death pathways are conserved across broad evolutionary kingdoms. Our results reveal that anti-apoptotic genes facilitate maintenance of metabolic activity at the whole plant level to create favorable conditions for cellular survival. It is these conditions that are crucial and conducive to the plants ability to tolerate/adapt to extreme environments.

Synthesis, growth, and characterization of a new NLO material 3-(2,3-dimethoxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one

3-(2,3-Dimethoxyphenyl)-1-(pyridin-2-yl)prop-2-en-1-one (DMPP) a potential second harmonic generating (SHG) has been synthesized and grown as a single crystal by the slow evaporation technique at ambient temperature. The structure determination of the grown crystal was done by single crystal X-ray diffraction study. DMPP crystallizes with orthorhombic system with cell parameters a = 20.3106(8)angstrom, b = 4.9574(2)angstrom, c = 13.4863(5)angstrom, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees and space group Pca2(1). The crystals were characterized by FT-IR, thermal analysis, UV-vis-NIR spectroscopy and SHG measurements. Various functional groups present in DMPP were ascertained by FTIR analysis. DMPP is thermally stable up to 80 degrees C and optically transparent in the visible region. The crystal exhibits SHG efficiency comparable to that of KDP. (C) 2011 Elsevier B.V. All rights reserved.

Tailoring the Magnetic and Optical Characteristics of Nanocrystalline BiFeO3 by Ce Doping

The Ce-doped BiFeO3 (BFO) nanoparticles (NPs) were synthesized using a facile solgel route with varying Ce concentrations in the range of 15 mol%. Ferroelectric transition temperature was found to shift from 723 degrees C +/- 5 degrees C for pristine BFO NPs to 534 degrees C +/- 3 degrees C for 5 mol% Ce-doped BFO NPs. UVVis absorption spectra of BFO NPs showed a significant blue shift of similar to 100 nm on Ce doping. The Fourier transformed infrared (FTIR) spectrum centered similar to 550 cm(-1) becomes considerably broadened on Ce doping which is due to additional closely spaced vibrational peaks as revealed by the second derivative FTIR analysis. High-frequency EPR measurements indicated that clustering occurs at high dopant levels, and that Fe is present as Fe(3+)corroborating Mossbauer measurements. The values of saturation and remanent magnetization for 3% Ce-doped BFO NPs are 3.03 and 0.49 emu/g, respectively, which are quite significant at room temperature, making it more suitable for technological applications.

Structural, electrical and dielectric properties of sputtered TiO2 films for Al/TiO2/Si capacitors

Metal-oxide semiconductor capacitors based on titanium dioxide (TiO2) gate dielectrics were prepared by RF magnetron sputtering technique. The deposited films were post-annealed at temperatures in the range 773-1173 K in air for 1 hour. The effect of annealing temperature on the structural properties of TiO2 films was investigated by X-ray diffraction and Raman spectroscopy, the surface morphology was studied by atomic force microscopy (AFM) and the electrical properties of Al/TiO2/p-Si structure were measured recording capacitance-voltage and current-voltage characteristics. The as-deposited films and the films annealed at temperatures lower than 773 K formed in the anatase phase, while those annealed at temperatures higher than 973 K were made of mixtures of the rutile and anatase phases. FTIR analysis revealed that, in the case of films annealed at 1173 K, an interfacial layer had formed, thereby reducing the dielectric constant. The dielectric constant of the as-deposited films was 14 and increased from 25 to 50 with increases in the annealing temperature from 773 to 973 K. The leakage current density of as-deposited films was 1.7 x 10(-5) and decreased from 4.7 X 10(-6) to 3.5 x 10(-9) A/cm(2) with increases in the annealing temperature from 773 to 1173 K. The electrical conduction in the Al/TiO2/p-Si structures was studied on the basis of the plots of Schottky emission, Poole-Frenkel emission and Fowler-Nordheim tunnelling. The effect of structural changes on the current-voltage and capacitance-voltage characteristics of Al/TiO2/p-Si capacitors was also discussed.

Molecular profiling of sepsis in mice using Fourier Transform Infrared Microspectroscopy

Sepsis is a life threatening condition resulting from a high burden of infection. It is a major health care problem and associated with inflammation, organ dysfunction and significant mortality. However, proper understanding and delineating the changes that occur during this complex condition remains a challenge. A comparative study involving intra-peritoneal injection of BALB/c mice with Salmonella Typhimurium (infection), lipopolysaccharide (endotoxic shock) or thioglycollate (sterile peritonitis) was performed. The changes in organs and sera were profiled using immunological assays and Fourier Transform Infrared (FTIR) micro-spectroscopy. There is a rapid rise in inflammatory cytokines accompanied with lowering of temperature, respiratory rate and glucose amounts in mice injected with S. Typhimurium or lipopolysaccharide. FTIR identifies distinct changes in liver and sera: decrease in glycogen and protein/lipid ratio and increase in DNA and cholesteryl esters. These changes were distinct from the pattern observed in mice treated with thioglycollate and the differences in the data obtained between the three models are discussed. The combination of FTIR spectroscopy and other biomarkers will be valuable in monitoring molecular changes during sepsis. GRAPHICS] Intra-peritoneal infection with high dose of Salmonella Typhimurium leads to rapid increase in inflammatory cytokines, e.g. Tnf alpha (A). FTIR analysis of liver (B) and sera (C) identifies several metabolic changes: glycogen, protein/lipid, cholesteryl esters and DNA.

Obtenção do copolímero de acrilonitrila e vinil-imidazol a partir da modificação química da poliacrilonitrila

Polímeros contendo anéis heterocíclicos, como o imidazol, possuem um grande interesse comercial e científico devido ao seu emprego em diversas áreas. Esses polímeros podem ser obtidos pela modificação química de polímeros comerciais como a poliacrilonitrila. Geralmente, esse tipo de reação é realizada por aquecimento convencional (térmico). Entretanto, mais recentemente, a irradiação por micro-ondas também começou a ser utilizada como fonte de energia para esse fim. Nesta Dissertação foi estudada, comparativamente, a modificação química da poliacrilonitrila comercial com etilenodiamina sob ativação de P2S5, empregando como fonte de aquecimento: o método convencional (térmico) e irradiação de micro-ondas, geradas em forno de micro-ondas doméstico e em reator de micro-ondas (Discover CEM), para produzir o copolímero de poliacrilonitrila e 2-vinil-imidazol. As reações foram efetuadas em diferentes tempos reacionais, em diferentes temperaturas no reator de micro-ondas e em diferentes potências do forno doméstico. Os copolímeros produzidos foram caracterizados por espectroscopia na região do infravermelho (FTIR) e por ressonância magnética de núcleo de hidrogênio (NMR-1H). A poliacrilonitrila foi modificada quimicamente com sucesso em todos os métodos empregados, como foi verificado pela sua análise de FTIR. Os melhores resultados obtidos foram: em 48 h de aquecimento térmico, 20 min de irradiação de micro-ondas em forno doméstico e 20 min a 80C em reator de micro-ondas, no entanto todas as análises indicaram uma derivatização abaixo de 10 %