Spectroscopy - Volume 24, issue 6

Authors: Wang, Shuang | Zhao, Jianhua | Lui, Harvey | He, Qingli | Zeng, Haishan

Article Type: Research Article

Abstract: Raman spectroscopy has been used as a sensitive tool for studying biological tissue and evaluating disease. In many applications, microscopic level resolution spectral analysis is desirable. And this has been performed mostly by expensive commercial confocal micro-Raman systems. In this research, we present a simple method for building an economical and modular Raman microspectroscopy system that combines a microscope with a Raman spectrometer using an optical fiber bundle. The bundle with a circular collection end is positioned at an image plane of the microscope to collect Raman signals from the interested micro-location on the sample. The light delivery end is …specially configured so that its 37 fibers are arranged along a straight line to fit into the spectrometer entrance slit. This configuration improves light collection efficiency and maintains high spectral resolution. To battle the great background autofluorescence and Raman signals that could originate from the microscope slides and optics due to the non-confocal set-up of our simplified system, conventional normal-incident illumination is replaced by oblique illumination at 45° degrees and the microscope slides are coated with gold. We demonstrated the usefulness of the system by measuring micro-Raman spectra from different skin layers on vertical sections of normal skin tissue samples. Show more

Keywords: Microscopy Raman, near infrared fluorescence imaging, gold-coated slide, oblique illumination, tissue Raman spectroscopy, skin

DOI: 10.3233/SPE-2010-0487

Citation: Spectroscopy, vol. 24, no. 6, pp. 577-583, 2010

Authors: Knoll, W. | Natali, F. | Peters, J. | Nanekar, R. | Wang, C. | Kursula, P.

Article Type: Research Article

Abstract: Myelin is a multilamellar membrane which, wrapping the nerve axons, increases the efficiency of nervous signal transmission. Indeed, the molecular components of the myelin sheath interact tightly with each other and molecules on the axonal surface to drive myelination, to keep both myelin and the axon intact, and to transduce signals from myelin to the axon and vice versa. Myelin is strongly affected in human demyelinating diseases in both the central and peripheral nervous system (CNS and PNS, respectively). Despite the presence of a well-defined set of myelin-specific proteins, little is known about the structure and the dynamics of these …proteins, their interactions with the membrane and their influence on myelin stability. We present here the first neutron scattering results on the dynamics of the myelin sheath in PNS and of the interaction between its constituents. Specifically, the human P2 protein is shown to stabilize the lipid membrane upon binding to it. Show more

Keywords: Membrane dynamics, neutron scattering, myelin

DOI: 10.3233/SPE-2010-0479

Citation: Spectroscopy, vol. 24, no. 6, pp. 585-592, 2010

Authors: Oshtrakh, M.I. | Semionkin, V.A. | Milder, O.B. | Alenkina, I.V. | Novikov, E.G.

Article Type: Research Article

Abstract: Application of Mössbauer spectroscopy with a high velocity resolution for study different hemoglobins, ferritin, its models and chicken liver and spleen as well as normal and lymphoid chicken spleen demonstrated revealing of small variations of hyperfine parameters related to small variations of iron stereochemistry in biomolecules. These data demonstrate that Mössbauer spectroscopy with a high velocity resolution may be useful in biomedical research to distinguish small variations of iron-containing proteins in normal and pathological cases.

Keywords: Mössbauer spectroscopy with a high velocity resolution, biomedical applications, small variations

DOI: 10.3233/SPE-2010-0489

Citation: Spectroscopy, vol. 24, no. 6, pp. 593-599, 2010

Authors: Khalique Ahmed, M. | McLeod, Michael P. | Nézivar, Jean | Giuliani, Allison W.

Article Type: Research Article

Abstract: Recently there have been reports of the contamination of cough syrups with Diethylene Glycol (DEG). The consumption of such cough syrups has devastating effects on the health. In this paper we report evidence that Fourier transform infrared (FT-IR) and near-infrared (NIR) spectroscopic techniques are viable, simple, cost effective, rapid and fool proof methods for the identification and quantification of DEG in glycerin based cough syrups. The FT-IR and NIR spectra of the glycerin based cough syrup and up to 50:50 mixtures of DEG in cough syrup are recorded. The major peaks in the FT-IR spectrum of the cough syrup are …assigned to the OH stretching (~3300 cm−1 ), CH stretching (~2900 cm−1 ), CH bending (1500–1200 cm−1 ) and C–O stretching (1200–900 cm−1 ) vibrational modes. In the FT-IR spectra of the mixtures, DEG contribute distinct peaks due to the vibrations of the C–O (920 cm−1 ) and OC2 H4 (892 cm−1 ) moieties of its backbone and form the basis of the DEG detection and quantification. The prominent peaks of the NIR spectra of cough syrup and DEG are assigned to the first overtones of OH and CH, and to the combination of OH and CH fundamental vibrations. Both FT-IR and NIR Partial Least Square (PLS) calibrations produced correlation coefficients of 0.98. Show more

Keywords: Infrared spectroscopy, near-infrared spectroscopy, cough syrup, diethylene glycol, contaminant, detection

DOI: 10.3233/SPE-2010-0482

Citation: Spectroscopy, vol. 24, no. 6, pp. 601-608, 2010

Authors: Erukhimovitch, V. | Tsror (Lahkim), L. | Hazanovsky, M. | Huleihel, M.

Article Type: Research Article

Abstract: Fungi are considered as serious pathogens to many plants and can cause a severe economic damage. The available methods for identification of fungi are time consuming and not always very specific. In the present study we examined the potential of FTIR microscopy for direct detection and identification of different fungal potato pathogens on the surface of potato tubers. Unique spectral bands for each of the examined fungal pathogens appeared in the spectra of naturally infected potatoes. These results strongly support the potential of FTIR microscopy for successful detection and probably discrimination between different fungal pathogens directly from the infected tissue.

Keywords: Fungal detection, fungi, FTIR microscopy, spectral peaks, potato

DOI: 10.3233/SPE-2010-0483

Citation: Spectroscopy, vol. 24, no. 6, pp. 609-619, 2010

Authors: Moreira, Leonardo M. | Lyon, Juliana P. | Tursi, Suellen M.S. | Trajano, Isis | Felipe, Monalisa P. | Costa, Maricília S. | Rodrigues, Máira R. | Codognoto, Lúcia | de Oliveira, Hueder P.M.

Article Type: Research Article

Abstract: Infections caused by Candida albicans are of increasing concern, especially considering immunodepressed patients. The toxicity of most antifungal agents, the great number of cases with recidives, as well as the emergence of resistant samples has provoked the evaluation of new forms of therapy. In this context, the photodynamic therapy (PDT) presents auspicious antimicrobial properties, stimulating the development of trials employing several kinds of photosensitizers. In the present work, the application of different kind of Azure dyes as photosensitizer in PDT against C. albicans was evaluated through instrumental measurements of electronic spectroscopy. In fact, the values of optical density were a …precise indicator of the growth inhibition of the microorganisms. Indeed, Azures are phenothiazinium derivatives that constitute a very relevant class of compounds with several biomedical applications, such as photoantimicrobial therapy against local bacterial infection, tuberculosis, trypanosomiasis, malaria, Rickettsia, yeasts, viral infection n and cancer. Azure A, Azure B, Azure A thiocyanate, Azure B BF4 , Azure A eosinate are the dyes tested against C. albicans. The results denoted completely distinct behaviors to the different types of Azure compound evaluated in this work. In fact, Azure A and Azure A eosinate presented significant results when irradiated with 56 J/cm2 , since the growth inhibition of C. albicans reached approximately 60%. This Azure compounds have significant potential to be employed as photosensitizer (PS) in PDT, especially in cases of mucocutaneous candidosis. The spectroscopic evaluation was very effective to the detection of slight alterations in the growth of the microorganisms, denoting that this kind of analysis is an excellent alternative to determine growth inhibition of Candida albicans. The experimental data are discussed in details in agreement with recent results from literature. Show more

Keywords: Photodynamic therapy (PDT), photosensitizer (PS), Azures, Candida albicans

DOI: 10.3233/SPE-2010-0484

Citation: Spectroscopy, vol. 24, no. 6, pp. 621-628, 2010

Authors: Lam, Simon C.H. | Chung, Joanne W.Y. | Fan, K.L. | Wong, Thomas K.S.

Article Type: Research Article

Abstract: The aim of this paper is to evaluate development of the non-invasive blood glucose measurement of near infrared (NIR) spectroscopy. The results showed that NIR spectroscopy might obtain glucose concentration of up to 200% difference under a same environmental condition with two months apart due to time and machine drifts. These effects can restrict the development of the non-invasive blood glucose measurement. Partial least square (PLS) regression was used, which showed advantage over using simple absorbance for glucose concentration. Non-invasive blood glucose measurement of health subjects (non-diabetics) was also investigated. The results showed that R correlation coefficient of prediction (Rp …) was 0.48 and root mean square of prediction (rmsep) was 1.34 mmol/l. The error was mainly due to the physiological effect of different subjects. Show more

Keywords: Spectroscopy, machine drift, time drift, physiological effect, PLS, PDS, Beer's law

DOI: 10.3233/SPE-2010-0485

Citation: Spectroscopy, vol. 24, no. 6, pp. 629-639, 2010

Authors: Saini, Balraj | Kaushal, Manjula | Bansal, Gulshan

Article Type: Research Article

Abstract: A spectrofluorimetric method for estimation of mirtazapine in human whole blood was developed and validated. The recovery efficiency of the processing method was 95–98%. The analytical method was linear over drug concentration of 10–200 ng/ml. The limit of quantification was 10 ng/ml. The method was precise with %RSD for intra-day and inter-day precision being <3.0 and 1.5, respectively. Excellent recoveries (97.87–99.69%) were achieved during accuracy studies. The method was robust to small changes in processing method and instrumental parameters. The present method can be employed for direct fluorimetric determination of mirtazapine in human whole blood during clinical studies.

Keywords: Mirtazapine, spectrofluorimetry, protein precipitation, human blood, validated

DOI: 10.3233/SPE-2010-0488

Citation: Spectroscopy, vol. 24, no. 6, pp. 641-649, 2010

Authors: Polyhach, Yevhen | Jeschke, Gunnar

Article Type: Research Article

Abstract: Electron paramagnetic resonance studies on diamagnetic proteins are based on site-directed spin labelling and require relatively much effort for engineering cystein point mutations as well as expressing and labelling the protein. Therefore, it is advantageous to predict those sites and pairs of sites that can provide the most precise and most reliable information on accessibility and distances. Systematic site scans based on a rotamer library approach for spin label side groups allow for such predictions. Figures of merit are defined that can be used to rank sites according to their potential suitability in studies of structure and structural changes. Such …site scans can still provide useful results if only a backbone model and the amino acid sequence of the protein are known. Show more

Keywords: EPR spectroscopy, site-directed spin labelling, membrane proteins, molecular modelling, distance measurements

DOI: 10.3233/SPE-2010-0490

Citation: Spectroscopy, vol. 24, no. 6, pp. 651-659, 2010

Article Type: Other

Citation: Spectroscopy, vol. 24, no. 6, pp. 661-671, 2010