ORGANIC-CARBON DISTRIBUTION IN THE SURFACE SEDIMENTS OF THE SEA-OF-MARMARA AND ITS CONTROL BY THE INFLOWS FROM ADJACENT WATER MASSES

The organic carbon contents and textural composition of a total of 166 surficial sediment samples (from 10 to 1226 m water depths) together with data on primary productivity rates and dissolved oxygen concentrations have been studied to investigate the main controls on the distribution of organic carbon buried within the modern sediments across the Sea of Marmara

Quantification of polydimethylsiloxane concentration in turbid samples using raman spectroscopy and the method of partial least squares

This paper presents a preliminary application of Raman spectroscopy in conjunction with the chemometric method of partial least squares to predict silicone concentrations in homogenous turbid samples. The chemometric technique is applied to Raman spectra to develop an empirical, linear model relating sample spectra to polydimethylsiloxane (silicone) concentration. This is done using a training set of samples having optical properties and known concentrations representative of those unknown samples to be predicted. Partial least squares, performed via cross-validation, was able to predict silicone concentrations in good agreement with true values. The detection limit obtained for this preliminary investigation is similar to that reported in the magnetic resonance spectroscopy literature. The data acquisition time for this Raman-based method is 200 s which compares favourably with the 17 h acquisition required for magnetic resonance spectroscopy to obtain a similar sensitivity. The combination of Raman spectroscopy and chemometrics shows promise as a tool for quantification of silicone concentrations from turbid samples

Quantification of polydimethylsiloxane concentration in turbid samples using raman spectroscopy and the method of partial least squares

This paper presents a preliminary application of Raman spectroscopy in conjunction with the chemometric method of partial least squares to predict silicone concentrations in homogenous turbid samples. The chemometric technique is applied to Raman spectra to develop an empirical, linear model relating sample spectra to polydimethylsiloxane (silicone) concentration. This is done using a training set of samples having optical properties and known concentrations representative of those unknown samples to be predicted. Partial least squares, performed via cross-validation, was able to predict silicone concentrations in good agreement with true values. The detection limit obtained for this preliminary investigation is similar to that reported in the magnetic resonance spectroscopy literature. The data acquisition time for this Raman-based method is 200 s which compares favourably with the 17 h acquisition required for magnetic resonance spectroscopy to obtain a similar sensitivity. The combination of Raman spectroscopy and chemometrics shows promise as a tool for quantification of silicone concentrations from turbid samples

DISTRIBUTION OF SURFICIAL SHELF SEDIMENTS IN THE NORTHEASTERN AND SOUTHWESTERN PARTS OF THE SEA OF MARMARA - STRAIT AND CANYON REGIMES OF THE DARDANELLES AND BOSPORUS

Surficial sediment samples collected from the northeastern and southwestern shelf regions of the Sea of Marmara, together with data available from other sources, indicate marked variations in sediment compositions resulting from differences in topographical, hydrological and biological conditions. In the strait channels of the Dardanelles and Bosporus, where strong undercurrents prevail, the floor was covered mostly by coarse-grained sediments (rich in sand and gravel). However, in areas of relatively low energy conditions, sediments contained appreciable amounts of mud, with a tendency towards an increase in the amount of clay towards the open sea. The effects of the strong undercurrents on the bedforms was also apparent in the southern Strait of Bosporus where sidescan sonar surveys revealed the presence of asymmetrical sand ripples. Although terrigenous mud is the principal sediment type in the two canyons (Dardanelles and South Bosporus), the sediments, in particular on the floor of South Bosporus Canyon, show a distinct contrast between the inner N-S and outer E-W trending parts: along its axis, where depths are greatest, the outer part of the canyon appears to contain much more coarse sediment (in part derived from the benthic communities) than the inner canyon. In general, both the topography-related current regimes and the biological activities in the study areas mostly determine the types and modes of sediment distribution. Among the biogenic components, the calcareous corraline algae Rhodophycae (chiefly Lithothamnium calcareum and L.fruticolusum) and the molusc families Galeommatacae and Cerithiospidae are associated with the prevailing Mediterranean undercurrents, especially in the shallower waters of the junction of the Sea of Marmara and Strait of Bosporus. The relatively abundant mollusc species Mytilus galloprovincialis and Modiolus barbatus and the Trochidae in the Strait of Bosporus are largely affected by Black Sea waters. The wide range of carbonate concentrations in the sediments generally reflects the relative abundances of biogenic admixtures in the samples. High carbonate percentages in the sediments are usually associated with low mud contents, and vice versa. Interestingly, the organic carbon contents of the sediments generally increase with proximity to the Black Sea, suggesting influxes of appreciable amounts of organic matter from the Black Sea

Raman spectroscopy for quanitification of polydimethylsiloxane concentration in turbid samples

This paper presents a preliminary application of Raman spectroscopy in conjunction with the chemometric method of Partial Least Squares to predict silicone concentrations in homogeneous turbid samples. The chemometric technique is applied to Raman spectra to develop an empirical, linear model relating sample spectra to polydimethysiloxane (silicone) concentration. This is done using a training set of samples having optical properties and known concentrations representative of those unknown samples to be predicted. Partial Least Squares, performed via cross- validation, was able to predict silicone concentrations in good agreement with true values. The detection limit obtained for this preliminary investigation is on par with that of magnetic resonance spectroscopy. The data acquisition time for this Raman based method is 200 seconds, which compares favorably with the 17 hour acquisition required for magnetic resonance spectroscopy to obtain a similar sensitivity. The combination of Raman spectroscopy and chemometrices shows promise as a tool for quantification of silicone concentrations from turbid samples. ©2005 Copyright SPIE - The International Society for Optical Engineering

Raman spectroscopy for quanitification of polydimethylsiloxane concentration in turbid samples

This paper presents a preliminary application of Raman spectroscopy in conjunction with the chemometric method of Partial Least Squares to predict silicone concentrations in homogeneous turbid samples. The chemometric technique is applied to Raman spectra to develop an empirical, linear model relating sample spectra to polydimethysiloxane (silicone) concentration. This is done using a training set of samples having optical properties and known concentrations representative of those unknown samples to be predicted. Partial Least Squares, performed via cross- validation, was able to predict silicone concentrations in good agreement with true values. The detection limit obtained for this preliminary investigation is on par with that of magnetic resonance spectroscopy. The data acquisition time for this Raman based method is 200 seconds, which compares favorably with the 17 hour acquisition required for magnetic resonance spectroscopy to obtain a similar sensitivity. The combination of Raman spectroscopy and chemometrices shows promise as a tool for quantification of silicone concentrations from turbid samples. ©2005 Copyright SPIE - The International Society for Optical Engineering

Determination of optical properties in highly attenuating media with an endoscope-compatible reflectance approach

Accurate in vivo optical property data in the ultraviolet to visible range are scarce for many endoscope-accessible organs, yet such information is essential for understanding light propagation and identifying dosimetry standards for biomedical optical spectroscopy. We have performed a preliminary study towards the development of a reflectance-based system for endoscopic measurement of tissue optical properties relevant to fluorescence spectroscopy. To address the constraint of instrument channel diameter and strong attenuation of light in the spectral region of interest, maximum fiber separation distance was limited to 2.5 mm. Measurements were performed on tissue phantoms for a range of optical properties relevant to gastrointestinal mucosal tissues in the ultraviolet to visible range: absorption coefficients from 1 to 256 cm-1 and reduced scattering coefficients from 5 to 25 cm-1. Neural network and partial least squares algorithms were trained on radial reflectance profiles generated by a Monte Carlo model as well as by experimental data. These routines were then used to estimate absorption and reduced scattering coefficients from reflectance data. Results are discussed in terms of the optimization of models for optical property determination

Determination of optical properties in highly attenuating media with an endoscope-compatible reflectance approach

Accurate in vivo optical property data in the ultraviolet to visible range are scarce for many endoscope-accessible organs, yet such information is essential for understanding light propagation and identifying dosimetry standards for biomedical optical spectroscopy. We have performed a preliminary study towards the development of a reflectance-based system for endoscopic measurement of tissue optical properties relevant to fluorescence spectroscopy. To address the constraint of instrument channel diameter and strong attenuation of light in the spectral region of interest, maximum fiber separation distance was limited to 2.5 mm. Measurements were performed on tissue phantoms for a range of optical properties relevant to gastrointestinal mucosal tissues in the ultraviolet to visible range: absorption coefficients from 1 to 256 cm-1 and reduced scattering coefficients from 5 to 25 cm-1. Neural network and partial least squares algorithms were trained on radial reflectance profiles generated by a Monte Carlo model as well as by experimental data. These routines were then used to estimate absorption and reduced scattering coefficients from reflectance data. Results are discussed in terms of the optimization of models for optical property determination

<title>Determination of optical properties in highly attenuating media with an endoscope-compatible reflectance approach</title>

Accurate in vivo optical property data in the ultraviolet to visible range are scarce for many endoscope-accessible organs, yet such information is essential for understanding light propagation and identifying dosimetry standards for biomedical optical spectroscopy. We have performed a preliminary study towards the development of a reflectance-based system for endoscopic measurement of tissue optical properties relevant to fluorescence spectroscopy. To address the constraint of instrument channel diameter and strong attenuation of light in the spectral region of interest, maximum fiber separation distance was limited to 2.5 mm. Measurements were performed on tissue phantoms for a range of optical properties relevant to gastrointestinal mucosal tissues in the ultraviolet to visible range: absorption coefficients from 1 to 256 cm-1 and reduced scattering coefficients from 5 to 25 cm-1. Neural network and partial least squares algorithms were trained on radial reflectance profiles generated by a Monte Carlo model as well as by experimental data. These routines were then used to estimate absorption and reduced scattering coefficients from reflectance data. Results are discussed in terms of the optimization of models for optical property determination