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Results for “Spectrum Analysis, Raman”
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Resonance Raman spectroscopy of the photoreceptor-like pigment of Halobacterium halobium.
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[Raman spectroscopic investigations for dental materials. 2].
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[Resonance Raman scattering of metal-containing proteins].
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Vibrational frequencies and structural determination of Al(8)S(12).
The normal mode frequencies and corresponding vibrational assignments of Al(8)S(12) in T(h) symmetry are examined theoretically using the Gaussian98 set of quantum chemistry codes. All normal modes were successfully assigned to one of four types of motion (Al-S stretch, Al-S-Al bend, S-Al-S bend, and Al-S-Al wag) predicted by a group theoretical analysis. Normal mode frequencies are predicted and calculated infrared intensities and Raman activities are presented. The thermodynamics of the reaction 2Al(4)S(6)-->Al(8)S(12) are examined.
Hydrogen bonding and molecular vibrations of 3,5-diamino-1,2,4-triazole.
This work deals with the analysis of hydrogen bonding and the vibrational spectroscopy of 3,5-diamino-1,2,4-triazole by means of quantum chemical calculations. The mid and far FTIR and FT-Raman spectra were measured in the condensed state. The fundamental vibrational frequencies were calculated under different possible symmetries by applying the density functional theory with the B3LYP functional and the 6-31G* basis set. The results of the calculations obtained under C(2) symmetry produces the global minimum on the potential energy surface. The vibrational spectra were interpreted with the aid of normal coordinate analysis based on scaled density functional force field. The infrared and Raman spectra were also predicted from the calculated intensities.
[Raman spectra of Cu/Zn superoxide dismutase and L-cysteine used as an electron transfer promoter].
In author's laboratory, it has been demonstrated with electrochemical techniques that L-cysteine can be used as an effective electron transfer promoter to accelerate the electron transfer process of Cu/Zn superoxide dismutase on gold electrode. In order to reveal the mechanism of this promotion, confocal microscopic Raman spectroscopic technique is employed here to obtain Raman spectra of solid state SOD and L-cysteine modified gold electrode. Moreover, Raman spectra of L-cysteine modified gold electrode with two different approaches are also obtained. Analysis and discussion for these Raman spectra are reported.
[Bone destruction in cholesteatoma--Raman spectroscopic analysis on the bone destruction].
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Fourier transform-Raman spectroscopy for the qualitative and quantitative characterization of sulfasalazine-containing polymeric microspheres.
FT-Raman spectroscopy (FTRS) has been used to characterize microspheres produced from the pharmaceutical polymer Eudragit RS containing a range of concentrations of the drug sulfasalazine. While pure sulfasalazine produced an intense and complex Raman spectrum, the spectrum of drug-free Eudragit RS microspheres was considerably weaker in intensity and contained only a few prominent Raman scattering peaks. In spectra of the drug-polymer microspheres, peaks arising from the individual components could be identified. This enabled a quantitative analysis to be undertaken by calculating the ratio between the area of a sulfasalazine peak and the area of a Eudragit RS peak for each microsphere spectrum. A correlation was shown between the peak area ratio and the microsphere sulfasalazine content. FTRS was then applied to a series of microsphere samples which had been dissoluted into pH 7 buffer for 1, 3, 6, 9, 12, or 24 hr. For each spectrum, the drug-polymer peak area ratio was determined and this in turn enabled calculation of the residual drug content of the microsphere sample. FTRS-calculated data showed good agreement with microsphere drug content values determined spectrophotometrically.
[Self-assembly of nano-structured silver particle and its surface-enhanced Raman spectroscopic application].
Planar arrays of nano-structured silver particle were self-assembled on poly-lysine modified glass surfaces. SEM characterization indicates that silver particles were assembled as a sub-monolayer. A comparison of the UV/Vis spectra of silver colloid and the arrays demonstrates that the poly-lysine layer showed size selectivity for the self-assembling silver particles. Surface-enhanced FT-Raman spectrum of methylviolegen on the array reveals that Raman scattering in near IR region was mainly enhanced via a chemical enhancement mechanism.
Quantitative NIR Raman analysis in liquid mixtures.
The capability to obtain quantitative information of a simple way from Raman spectra is a subject of considerable interest. In this work, this is demonstrated for mixtures of ethanol with water and rhodamine-6G (R-6G) with methanol, which were analyzed directly in glass vessel. The Raman intensities and a simple mathematical model have been used and applied for the analysis of liquid samples. It is starting point to generate a general expression, from the experimental spectra, as the sum of the particular expression for each pure compound allow us to obtain an expression for the mixtures which can be used for determining concentrations, from the Raman spectrum, of the mixture.
Steric disposition of O2 in oxyhemoglobin as revealed by its resonance Raman spectrum.
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Raman spectroscopy-based creatinine measurement in urine samples from a multipatient population.
Spectroscopic methods of urinalysis offer several advantages over chemical methods, including less sample contact and higher information content. In particular, urine creatinine has been the subject of several spectroscopic studies. We report the first use of Raman spectroscopy to measure creatinine concentrations in unaltered urine samples from a multipatient population. Using near-infrared excitation and a hybrid linear analysis calibration method, a root mean squared error of cross-validation (RMSECV) of 4.9 mg/dL was obtained. The error in the reference chemical method was 1.1 mg/dL. This result shows that the Raman spectroscopy can measure creatinine at clinical levels even in the presence of patient-to-patient variations. Because most assays in urine require creatinine concentration in order to correct for fluctuations in water content, measurement of creatinine is the first step towards more extensive Raman-based urinalysis.
[Confocal Raman microspectroscopic study of human breast morphological elements].
Breast tissue sections were examined by means of confocal Raman spectroscopy with an excitation wavelength of 633 nm. Acquired using a microscopic mapping approach with the sample volume of -2 microm3, these spectra were compared with the ones of the commercially available actin, DNA, collagen (type I), triolein etc. Some spectra were distinguished and identified and characterize the morphological elements like cell cytoplasm, extracellular matrix etc. The cell nucleus spectrum was also obtained by K-means cluster analysis. The correlation analysis showed that the spectrum from a morphological element is highly correlated with that from the corresponding purified chemical. The spectroscopic characterization of these morphological elements was then investigated. This study is helpful to understanding the chemical/morphological basis of the Raman spectrum and designing the Raman microspectroscopic model of human breast tissue.
Vibrational frequencies and structural determination of trichloroboroxine.
The normal mode frequencies and corresponding vibrational assignments of trichloroboroxine (B3O3Cl3) in D3h symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of five types of motion (B-Cl stretch, B-O stretch, B-Cl bend, O-B-O bend, and B(OOCl) umbrella motion) predicted by a group theoretical analysis. By comparing the vibrational frequencies with IR and Raman spectra available in the literature, a set of scaling factors is derived. Molecular orbitals and bonding are examined.
Metabolic fingerprinting in disease diagnosis: biomedical applications of infrared and Raman spectroscopy.
The ability to diagnose the early onset of disease, rapidly, non-invasively and unequivocally has multiple benefits. These include the early intervention of therapeutic strategies leading to a reduction in morbidity and mortality, and the releasing of economic resources within overburdened health care systems. Some of the routine clinical tests currently in use are known to be unsuitable or unreliable. In addition, these often rely on single disease markers which are inappropriate when multiple factors are involved. Many diseases are a result of metabolic disorders, therefore it is logical to measure metabolism directly. One of the strategies employed by the emergent science of metabolomics is metabolic fingerprinting; which involves rapid, high-throughput global analysis to discriminate between samples of different biological status or origin. This review focuses on a selective number of recent studies where metabolic fingerprinting has been forwarded as a potential tool for disease diagnosis using infrared and Raman spectroscopies.
Raman spectroscopy investigation of biological materials by use of etched and silver coated glass fiber tips.
The results for surface enhanced Raman scattering (SERS) studies on biological samples are reported. Etched and silver coated glass fiber tips were used as a SERS substrate. This method enabled the recording of spectra of biological samples, such as plant tissue or microbiological cells, with a high spatial resolution. Because of the low laser power used with the fiber tips, it was even possible to investigate tissues that are very sensitive toward laser power as it is used in a common micro-Raman setup.
Vibrational characterization of the tertiary amide and thioamide group.
Force field calculations and vibrational spectra of (CH(3))(2)NCOCON(CH(3))(2) (TMO), (CH(3))(2)NCOCSN(CH(3))(2) (TMMTO) and (CH(3))(2)NCSCSN(CH(3))(2) (TMDTO) are discussed. The amide and thioamide fundamentals and those of other simple tertiary amides are compared. A characteristic pattern in infrared and Raman is proposed.