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

Botta, Sergio B.; Ana, Patricia A.; Santos, Moises O.; Zezell, Denise M.; Matos, Adriana B.
Fonte: WILEY-BLACKWELL; MALDEN Publicador: WILEY-BLACKWELL; MALDEN
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
96.26%
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...

Avaliação da metodologia no infravermelho com Transformada de Fourier para análises do pH e ponto de congelamento em leite bovino; Evaluation of the methodology Fourier Transform Infrared for analysis of pH and freezing point in bovine milk

Araújo, Viviane Maia de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/10/2009 PT
Relevância na Pesquisa
96.33%
Objetivou-se com este trabalho avaliar a utilização da metodologia no infravermelho com Transformada de Fourier (ITF) na determinação do pH e ponto de congelamento (PC) no leite bovino. No primeiro estudo foram avaliados os efeitos das diferentes condições de conservação em amostras de leite para posterior análise do pH e do PC. Para tanto, foram coletadas, do tanque de 57 propriedades, amostras de três litros de leite. Cada amostra foi subdividida e transferida para 45 frascos de 40mL e distribuídas de acordo com a temperatura de armazenamento (-30C° - Congelado; 7°C - Resfriado; 25°C - Ambiente), idade da amostra (0, 3, 6 e 9dias) e níveis de adição de água (0, 2, 4 e 6%). Foram adicionadas pastilhas de bronopol (Microtabs®) aos 44 frascos, sendo que um foi mantido sem adição do conservante para tratamento controle. Os resultados obtidos, considerando as diferentes condições de conservação das amostras, e ainda, o efeito da adição do bronopol, foram avaliados por comparação de médias. As metodologias (referência e alternativa) foram correlacionadas em função da idade da amostra para o PC por análise de regressão linear. A sensibilidade e a especificidade foram calculadas para avaliação do desempenho do equipamento MilkoScanTM FT+ na detecção de água. A adição do bronopol não alterou as médias do pH...

Validação da metodologia de infravermelho com transformada de Fourier para identificação de adulteração em leite cru; Validation of the Fourier Transform Infrared spectroscopy to identify adulteration of raw milk

Cassoli, Laerte Dagher
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/10/2010 PT
Relevância na Pesquisa
96.33%
Objetivou-se avaliar a utilização da metodologia de infravermelho com transformada de Fourier (IVTF) na identificação de adulteração em leite cru. O objetivo no primeiro estudo foio de desenvolver calibração para identificação de adulteração através da comparação do espectro de leite adulterado com um espectro de referência para leite cru. Para construção do espectro referência foram coletadas 800 amostras de diferentes fazendas localizadas na região de estudo no período de agosto de 2009 a março de 2010. Através da análise de componentes principais, foram desenvolvidas oito calibrações com diferentes números de fatores (componentes principais). Para validação das diferentes calibrações, foram coletadas outras 100 amostras da mesma região de estudo. As amostras foram adulteradas com três diferentes adulterantes geralmente utilizados na adulteração do leite cru sendo eles: bicarbonato de sódio (BS), citrato de sódio (CS) e soro de queijo (SO). Para cada adulterante foram utilizadas três diferentes concentrações (BS: 0,05, 0,10 e 0,25 %; CS: 0,025, 0,050 e 0,075% e SO: 5, 10 e 20%). Para avaliação do desempenho das calibrações foram calculadas a especificidade e a sensibilidade para cada adulterante e respectivas concentrações. A especificidade foi de 92...

Caracterização bioquímica de lesões neoplásicas via espectroscopia de absorção no infravermelho por transformada de Fourier; Biochemical characterization of neoplastic lesions using Fourier transform Infrared spectroscopy

Lima, Cássio Aparecido
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/03/2015 PT
Relevância na Pesquisa
66.42%
Cânceres de pele não melanoma (CPNM) representam 95% das neoplasias cutâneas, dentre as quais o carcinoma espinocelular (CEC) é a forma mais agressiva devido a seu padrão de crescimento invasivo e possivelmente metastático. O padrão ouro para o diagnóstico é o exame clínico e avaliação histopatológica, que são subjetivos e dependem da experiência do médico e patologista envolvidos no procedimento. Considerando que o diagnóstico precoce é fundamental para alcançar um tratamento com resultados favoráveis, o presente trabalho utilizou a espectroscopia FTIR (Fourier transform infrared spectroscopy) para avaliar as alterações bioquímicas em pele normal causadas por lesões neoplásicas precursoras de carcinoma espinocelular. Para isto, as lesões foram induzidas quimicamente no dorso de camundongos Swiss via aplicação tópica de 9,10-dimetil-1,2-benzantraceno (DMBA) e 12-tetradecanoforbol-13-acetato (TPA) por um período de 28 semanas. Os espectros de absorção no infravermelho por transformada de Fourier foram coletados na região do infravermelho médio (4000-400 cm-1) no modo de reflexão total atenuada (ATR) e pré-processados para análise posterior. Considerou-se a amplitude da segunda derivada dos espectros de absorção como critério de comparação entre os grupos...

Fourier transform infrared spectroscopy (FTIR) and multivariative analysis for identification of defferent vegetable oils used in biodiesel production

Mueller, Daniela; Ferrao, Marco Flores; Marder, Luciano; Costa, Adilson Ben da; Schneider, Rosana de Cassia de Souza
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
76.21%
The main objective of this study was to use infrared spectroscopy to identify vegetable oils used as raw material for biodiesel production and apply multivariate analysis to the data. Six different vegetable oil sources—canola, cotton, corn, palm, sunflower and soybeans—were used to produce biodiesel batches. The spectra were acquired by Fourier transform infrared spectroscopy using a universal attenuated total reflectance sensor (FTIR-UATR). For the multivariate analysis principal component analysis (PCA), hierarchical cluster analysis (HCA), interval principal component analysis (iPCA) and soft independent modeling of class analogy (SIMCA) were used. The results indicate that is possible to develop a methodology to identify vegetable oils used as raw material in the production of biodiesel by FTIR-UATR applying multivariate analysis. It was also observed that the iPCA found the best spectral range for separation of biodiesel batches using FTIR-UATR data, and with this result, the SIMCA method classified 100% of the soybean biodiesel samples.

Prediction of cassava starch edible film properties by chemometric analysis of infrared spectra

Vicentini, N. M.; Dupuy, N.; Leitzelman, M.; Cereda, M. P.; Sobral, PJA
Fonte: Taylor & Francis Inc Publicador: Taylor & Francis Inc
Tipo: Artigo de Revista Científica Formato: 749-767
ENG
Relevância na Pesquisa
76.15%
Cassava starch has been shown to make transparent and colorless flexible films without any previous chemical treatment. The functional properties of edible films are influenced by starch properties, including chain conformation, molecular bonding, crystallinity, and water content. Fourier-transform infrared (FTIR) spectroscopy in combination with attenuated total reflectance (ATR) has been applied for the elucidation of the structure and conformation of carbohydrates. This technique associated with chemometric data processing could indicate the relationship between the structural parameters and the functional properties of cassava starch-based edible films. Successful prediction of the functional properties values of the starch-based films was achieved by partial least squares regression data. The results showed that presence of the hydroxyl group on carbon 6 of the cyclic part of glucose is directly correlated with the functional properties of cassava starch films.

Thermal degradation of both latex and latex cast films forming membranes : CCCombined TG/FTIR investigation

Agostini, D. L S; Constantino, C. J L; Job, A. E.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 703-707
ENG
Relevância na Pesquisa
66.32%
Latex collected from natural rubber trees forming membranes can be used as biomaterials in several fields being the temperature a key parameter. Thermogravimetry (TG) coupled to Fourier transform infrared spectroscopy (FTIR) is a useful technique to investigate the thermal degradation of both latex and cast films (membranes), wich were obtained from Hevea brasiliensis (RRIM 600 clone) and used without stabilization. The membranes were prepared by casting the latex onto a glass substrate at 65°C for 6 h. The thermal degradation was followed by FTIR spectra acquisition along the process, allowing the identification of the gaseous components evolved upon the thermal treatment. According to TG measurements, the main processes of thermal degradation of the latex and membranes occur at three temperature intervals for both. © 2008 Springer Science+Business Media, LLC.

Análise da saliva de pacientes com ardência bucal por espectroscopia de Fourier Transform Infrared (FT-IR)

Carvalho, Lais Morandini
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: 84 f. : il.
POR
Relevância na Pesquisa
66.42%
Pós-graduação em Biopatologia Bucal - ICT; The optical biopsy techniques consist in the analysis of tissues through its physical properties. Among these techniques, there is a Fourier Transform Infrared (FT-IR) spectroscopy, which has been used to identify patterns of molecular changes through vibrational modes. The aim of this study was to evaluate by FT-IR spectroscopy saliva samples from 14 patients complaining of burning mouth aiming to study global biochemical changes and compare the saliva of 14 patients without any complaint, matched for age and sex. To obtain results, the spectra acquired and stored by the control software of the spectrometer Fourier Transform Infrared (FT-IR) were converted to ASCII format for further processing and analysis be conducted in Minitab 16. The results revealed by the analysis performed by the graphics program Origin and Qytplot that there were differences in the intensities of the bands related to proteins and lipids, who presented with lower spectral intensity to the saliva of patients with burning complain. Therefore, it was concluded that the technique was effective for characterizing the presence of changes in the saliva of patients with burning compared saliva from normal patients; As técnicas de biópsia óptica consistem na análise de tecidos através das suas propriedades físicas. Dentre essas técnicas...

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

Souza, A. R. de; Cavassan, O.; Almeida, M. V. de; Legendre, A. O.; Bannach, G.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 187-189
ENG
Relevância na Pesquisa
76.15%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 12/21450-1; In this research, the bark powder of Anadenanthera peregrina var. falcata (angico) was characterized by means of simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC) and differential scanning calorimetry (DSC) in order to investigate the chemical features responsible for the flame retardant properties of this plant. The TG-DSC and DSC data evidenced that dehydration occurs between 40 and 140 degrees C and that the anhydrous solid is stable up to 195 degrees C, when thermal decomposition begins. Coupled thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) techniques were used to identify the volatile products evolved during the decomposition of the sample, showing that water and carbon dioxide are the majority products formed by its decomposition even at temperatures as low as 200 degrees C. The strong endothermic peak associated with the release of water provides a reasonable explanation for the fire retardant properties of angico. (C)2013 Elsevier B.V. All rights reserved.

Fourier Transform Infrared Spectroscopy (FTIR) for MUN analysis in normal and adulterated Milk

Oliveira,M.C.P.P.; Silva,N.M.A.; Bastos,L.P.F.; Fonseca,L.M.; Cerqueira,M.M.O.P.; Leite,M.O.; Conrrado,R.S.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2012 EN
Relevância na Pesquisa
76.15%
The objective of this study was to evaluate the CombiScope FTIR equipment based on Fourier Transform Infrared methodology (FTIR), to assess the content of milk urea nitrogen (MUN) in Brazil. Repeatability and reproducibility of CombiScopeTM FTIR (Delta Instruments), and comparison with an enzymatic automated method (Chemspec® 150; Bentley Instruments) were tested to measure raw milk urea nitrogen (MUN). Additionally, MUN levels stability after storage of raw milk samples at 4ºC, and 20ºC for up to 15 days, and capability and precision to detect extraneous urea added as an adulterant to the milk were evaluated by FTIR equipment. There was a high correlation coefficient for the analysis of MUN by FTIR equipment, when compared with the automated enzymatic method, with no significant difference between both. MUN concentration in raw milk remained stable at temperatures of 4ºC for up to 15 days of storage, but after 3 days of storage at 20ºC there was an increase in the MUN levels. The CombiScope FTIR equipment proved to be a reliable method for analysis of MUN content in raw milk. However, results for MUN were not linear with the amount of extraneous urea added to raw milk, having a significant difference for samples when 40mg/dL of urea was added to milk.

Multivariate quality control of lubricating oils using Fourier transform infrared spectroscopy

Borin,Alessandra; Poppi,Ronei Jesus
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2004 EN
Relevância na Pesquisa
96.26%
Multivariate quality control in conjunction with Fourier transform infrared Spectroscopy (FTIR) were used to qualitatively detect the class and the condition of lubricating oils. The multivariate approach was based on principal component analysis (PCA), first to classify the lubricating oil type (mineral, synthetic and semi-synthetic) and then to develop two control charts: a T² chart using the most significant principal components and a Q chart with the PC not used in the first chart. From these two charts it was possible to identify oil samples, based on a viscosity parameter, which were out of the pattern normally present in utilizable lubricating oils.

Fourier-Transform Raman and Fourier-Transform Infrared Spectroscopy (An Investigation of Five Higher Plant Cell Walls and Their Components).

Sene, CFB.; McCann, M. C.; Wilson, R. H.; Grinter, R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1994 EN
Relevância na Pesquisa
66.38%
Infrared and Raman spectra of sequentially extracted primary cell walls and their pectic polymers were obtained from five angiosperm plants. Fourier-transform Raman spectrometry was shown to be a powerful tool for the investigation of primary cell-wall architecture at a molecular level, providing complementary information to that obtained by Fourier-transform infrared microspectroscopy. The use of an extraction procedure using imidazole instead of cyclohexane trans-1,2-N,N,N[prime],N[prime]-diaminotetraacetate allows the extension of the infrared spectral window for data interpretation from 1300 to 800 cm-1, to 2000 to 800 cm-1, and allows us to obtain Raman spectra from extracted cell-wall material. Wall constituents such as pectins, proteins, aromatic phenolics, cellulose, and hemicellulose have characteristic spectral features that can be used to identify and/or fingerprint these polymers without, in most cases, the need for any physical separation. The Gramineae (rice [Oryza sativa], polypogon [Polypogon fugax steud], and sweet corn [Zea mays]) are spectroscopically very different from the nongraminaceous monocotyledon (onion [Allium cepa]) and the dicotyledon (carrot [Daucus carota]); this reflects differences in chemical composition and cross-linking of the walls. The possibility of a taxonomic classification of plant cell walls based on infrared and Raman spectroscopies and the use of spectral fingerprinting for authentication and detection of adulteration of products rich in cell-wall materials are discussed.

Identification of Early Biomarkers during Acetaminophen-Induced Hepatotoxicity by Fourier Transform Infrared Microspectroscopy

Gautam, Rekha; Chandrasekar, Bhagawat; Deobagkar-Lele, Mukta; Rakshit, Srabanti; Kumar B. N., Vinay; Umapathy, Siva; Nandi, Dipankar
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/09/2012 EN
Relevância na Pesquisa
66.38%
Acetaminophen is a widely prescribed drug used to relieve pain and fever; however, it is a leading cause of drug-induced liver injury and a burden on public healthcare. In this study, hepatotoxicity in mice post oral dosing of acetaminophen was investigated using liver and sera samples with Fourier Transform Infrared microspectroscopy. The infrared spectra of acetaminophen treated livers in BALB/c mice show decrease in glycogen, increase in amounts of cholesteryl esters and DNA respectively. Rescue experiments using L-methionine demonstrate that depletion in glycogen and increase in DNA are abrogated with pre-treatment, but not post-treatment, with L-methionine. This indicates that changes in glycogen and DNA are more sensitive to the rapid depletion of glutathione. Importantly, analysis of sera identified lowering of glycogen and increase in DNA and chlolesteryl esters earlier than increase in alanine aminotransferase, which is routinely used to diagnose liver damage. In addition, these changes are also observed in C57BL/6 and Nos2−/− mice. There is no difference in the kinetics of expression of these three molecules in both strains of mice, the extent of damage is similar and corroborated with ALT and histological analysis. Quantification of cytokines in sera showed increase upon APAP treatment. Although the levels of Tnfα and Ifnγ in sera are not significantly affected...

Combined Micro-Fourier Transform Infrared (FTIR) Spectroscopy and Micro-Raman Spectroscopy of Proterozoic Acritarchs: A New Approach to Palaeobiology

Walter, Malcolm R.; Knoll, Andrew; Javaux, Emmanuelle J.; Marshall, Craig P.
Fonte: Elsevier Publicador: Elsevier
EN_US
Relevância na Pesquisa
96.26%
Micro-scale analytical techniques permit correlation of chemistry with morphology of individual Proterozoic acritarchs (organic-walled microfossils), and thus provide new approaches for elucidating their biological affinities. A combination of micro-Fourier transform infrared (FTIR) spectroscopy and laser micro-Raman spectroscopy was used to investigate the organic structure and composition of individual acritarchs. Well preserved Neoproterozoic acritarchs from the Tanana Formation, Australia (ca. 590-565 Ma), and Mesoproterozoic acritarchs from the Roper Group (1.5-1.4 Ga), Australia, and Ruyang Group, China (1.4-1.3 Ga, age poorly resolved but certainly > 1000 Ma and < 1625 Ma) have thermal maturities that range from immature to oil window. FTIR spectra of Tanarium conoideum from the Tanana Formation contain intense aliphatic C-H stretching bands in the 2900 cm[super]-1 region relative to the C=C aromatic ring stretching band at 1600 cm[super]-1. This FTIR spectrum is consistent with the FTIR spectra obtained from algaenans isolated from extant chlorophyte and eustigmatophyte microalgae. FTIR spectra of Leiosphaeridia sp. from the Tanana Formation contain a less intense aliphatic C-H stretching band relative to the C=C aromatic ring stretching band. By comparison...

Analysis of saliva by Fourier transform infrared spectroscopy for diagnosis of physiological stress in athletes

Caetano Júnior,Paulo Cesar; Strixino,Juliana Ferreira; Raniero,Leandro
Fonte: Sociedade Brasileira de Engenharia Biomédica Publicador: Sociedade Brasileira de Engenharia Biomédica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
76.2%
Introduction Saliva is the most promising biofluid to monitor the physiological state of athletes, because this method is not invasive and has low contamination risks. The characterization of saliva by Fourier transform infrared spectroscopy (FT-IR) has been studied as an alternative technique to the standard clinical analysis. However, methodological procedures for saliva analysis are not completely clear, especially in terms of influence of storage conditions and sample preparations for infrared analysis. Thawed saliva includes a precipitate, which may influence the infrared spectral analysis. Thus, the purpose of this study was to show the spectral differences of the precipitate, supernatant, and a combo, as well as the best way to classify the physiological state of the athletes by FT-IR. Methods The saliva collection was performed before, immediately after, and two hours after a handball match. After the storage of samples at –20 ○C, it was possible to identify two phases (precipitate and supernatant) and to determine the biochemical differences between the spectra of each phase, which were distinctly analyzed by the second derivative and deconvolution bands. Results The precipitate and supernatant results showed characteristic bands...

Biochemical imaging of normal, adenoma, and colorectal adenocarcinoma tissues by Fourier transform infrared spectroscopy (FTIR) and morphological correlation by histopathological analysis: preliminary results

Piva,Juliana Aparecida de Almeida Chaves; Silva,João Lucas Rangel; Raniero,Leandro José; Lima,Carmen Silvia Passos; Arisawa,Emilia Angela Loschiavo; Oliveira,Cristiane de; Canevari,Renata de Azevedo; Ferreira,Juliana; Martin,Airton Abrahão
Fonte: Sociedade Brasileira de Engenharia Biomédica Publicador: Sociedade Brasileira de Engenharia Biomédica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
Relevância na Pesquisa
76.18%
Introduction The colorectal cancer is a major health problem worldwide. Histology is considered the gold standard for differential diagnosis. However, it depends on the observer's experience, which can lead to discrepancies and poor results. Spectroscopic imaging by Fourier transform infrared (FTIR) is a technique that may be able to improve the diagnosis, because it is based on biochemical differences of the structural constituents of tissue. Therefore, the main goal of this study was to explore the use of FTIR imaging technique in normal colon tissue, colorectal adenoma, and adenocarcinoma in order to correlate their morphological structures with their biochemical imaging. Methods Samples were collected from normal (n = 4), adenoma (n = 4), and adenocarcinoma human colorectal tissue (n = 4) from patients undergoing colonoscopy or surgical resection of colon lesions. The samples were sectioned with a cryostat in sequential sections; the first slice was placed on CaF2 slide and the second slice was placed on glass slide for histological analysis (HE staining). The cluster analyses were performed by the software Cytospec (1.4.02)®. Results In normal samples, biochemical analysis classified six different structures, namely the lamina propria of mucous glands (epithelial cells and goblet cells)...

Bicarbonate binding to the water-oxidizing complex in the photosystem II. A Fourier transform infrared spectroscopy study

Yruela Guerrero, Inmaculada; Allakhverdiev, Suleyman I.; Ibarra, José V.; Klimov, Vyacheslav V.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 3313625 bytes; application/pdf
ENG
Relevância na Pesquisa
96.26%
The definitive version is available at http://www.febsletters.org/article/S0014-5793(98)00271-3/; The light-induced Fourier transform infrared difference (FT-IR) spectrum originating from the donor side of O2-evolving photosystem (PS) II was obtained in non-depleted and CO2-depleted PSII membrane preparations. The observed spectrum free of contributions from the acceptor side signals was achieved by employing 2 mM/18 mM ferri-/ferrocyanide as a redox couple. This spectrum showed main positive bands at 1589 and 1365 cm−1 and negative bands at 1560, 1541, 1522 and 1507 cm−1. CO-depleted PSII preparations showed a quite different spectrum. The main positive and negative bands disappeared after depletion of bicarbonate. The addition of bicarbonate partially restored those bands again. Comparison between difference FT-IR spectra of untreated and bicarbonate-depleted PSII membranes indicated that the positive bands at 1589 and 1365 cm−1 can be assigned to COO− stretching modes from bicarbonate. The higher frequency corresponds to uas (COO−) and the lower frequency to us (COO−). 13C-Labeling FT-IR measurements confirmed these findings and also suggested that the negative band at 1560 cm−1 can be ascribed to uas (COO−). The data are discussed in the framework of the suggestion that bicarbonate can be a ligand to the Mn-containing water-oxidizing complex of PSII.; This work was supported by the Dirección General de Investigación Científica y Técnica (Grant PB 95-0219)...

Hardware and software optimization of fourier transform infrared spectrometry on hybrid-FPGAs

Bekker, Dmitriy
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
96.26%
With the increasing complexity of today’s spacecrafts, there exists a concern that the on-board flight computer may be overburdened with various processing tasks. Currently available processors used by NASA are struggling to meet the requirements of scientific experiments [1, 2]. A new computational platform will soon be needed to contend with the increasing demands of future space missions. Recently developed hybrid field-programmable gate arrays (FPGA) offer the versatility of running diverse software applications on embedded processors while at the same time taking advantage of reconfigurable hardware resources, all on the same chip package. These tightly coupled HW/SW systems consume less power than general-purpose singleboard computers (SBC) and promise breakthrough performance previously impossible with traditional processors and reconfigurable devices. This thesis takes an existing floating-point intensive data processing algorithm, used for on-board spacecraft Fourier transform infrared (FTIR) spectrometry, ports it into the embedded PowerPC 405 (PPC405) processor, and evaluates system performance after applying different hardware and software optimizations and architectural configurations of the hybrid-FPGA. The hardware optimizations include Xilinx’s floating-point unit (FPU) for efficient single-precision floating-point calculations and a dedicated single-precision dot-product co-processor assembled from basic floating-point operator cores. The software optimizations include utilizing a non-ANSI single-precision math library as well as IBM’s PowerPC performance libraries recompiled for double-precision arithmetic only. The outcome of this thesis is a fully functional...

A Systems level characterization and tradespace evaluation of a simulated airborne fourier transform infrared spectrometer for gas detection

Weiner, Aaron
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Dissertação
EN_US
Relevância na Pesquisa
86.26%
The remote sensing gas detection problem is one with no straightforward solution. While success has been achieved in detecting and identifying gases released from industrial stacks and other large plumes, the fugituve gas detection problem is far more complex. Fugitive gas represents a far smaller target and may be generated by leaking pipes, vents, or small scale chemical production. The nature of fugitive gas emission is such that one has no foreknowledge of the location, quantity, or transient rate of the targeted effluent which requires one to cover a broad area with high sensitivity. In such a scenario, a mobile airborne platform would be a likely candidate. Further, the spectrometer used for gas detection should be capable of rapid scan rates to prevent spatial and spectral smearing, while maintaining high resolution to aid in species identification. Often, insufficient signal to noise (SNR) prevents spectrometers from delivering useful results under such conditions. While common dispersive element spectrometers (DES) suffer from decreasing SNR with increasing spectral dispersion, Fourier Transform Spectrometers (FTS) generally do not and would seemingly be an ideal choice for such an application. FTS are ubiquitous in chemical laboratories and in use as ground based spectrometers...

A high-temperature Fourier transform infrared study of the interlayer and Si�O-stretching region in phengite-2 M 1

Mookherjee, Mainak; Redfern, Simon
Fonte: Mineralogical Society (UK) Publicador: Mineralogical Society (UK)
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
76.34%
A natural phengite-2M1 of composition (Kn95Na05)(AlnFen14Mg 10)2 (Si?25Al0 (OH196Fo04) [a 5.2173(1) A.b 9.0493(2) A, c 19.989 (1) A and B 95.734(4) ] was studied using in situ high-temperature FTIR. Correlations to structural changes were made using previously-reported neutron diffraction data from the same sample. Correlations have been made between the microscopic atomic displacements (arising from thermal effects) and analogous macroscopic properties, such as bond strain and ditrigonal distortions. Spectra were collected in the far-infrared region to study the behaviour of the interlayer (K ) cation and also in the mid-infrared region to distinguish the Si O stretching modes. We found anisotropic thermal expansion of the interlayer site. The K-O bond length is divided into K Oouter and K-Oinner and the K O bond length is correlated with the far-infrared spectra. The thermal dependence of the correlation between K O bond length and corresponding far-infrared stretching frequency is different from the effect of the chemical composition. We also found that the K O bond strain could be successfully resolved into the sum of inner strain and lattice strain. The Si O stretching mode. obtained from the mid-infrared measurements, showed only weak changes. However...