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Optical Analysis (optical + analysis)
Selected AbstractsIn Vivo Optical Analysis of Quantitative Changes in Collagen and Elastin During Arterial Remodeling,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2005Alexander Christov ABSTRACT Altered collagen and elastin content correlates closely with remodeling of the arterial wall after injury. Optical analytical approaches have been shown to detect qualitative changes in plaque composition, but the capacity for detection of quantitative changes in arterial collagen and elastin content in vivo is not known. We have assessed fluorescence spectroscopy for detection of quantitative changes in arterial composition in situ, in rabbit models of angioplasty and stent implant. Fluorescence emission intensity (FEI) recorded at sites remote from the primary implant site was correlated with immunohistochemical (IH) analysis and extracted elastin and collagen. FEI was significantly decreased (P < 0.05) after treatment with anti-inflammatory agents, and plaque area decreased on comparison with saline-treated rabbits after stent implant or angioplasty (P, 0.013). Excellent correlations for FEI with elastin and collagen I, III and IV content measured by IH (R2, 0.961) analysis were detected by multiple regression (MR) analysis. Good correlations also were found for FEI with elastin and collagen measured by high-performance liquid chromatography; MR analysis provided highly predictive values for collagen and elastin (R2, 0.994). Fluorescence spectroscopic analysis detects quantitative compositional changes in arterial connective tissue in vivo, demonstrating changes at sites remote from primary angioplasty and stent implant sites. [source] Novel mechanism for hair shine with special optical enhancement effect on blonde hairINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2010S. Iwai J. Cosmet. Sci., 60, 323,336 (May/June 2009) Accepted for publication October 21, 2008. Synopsis Compared with dark or brunette hair, blonde hair has different characteristic features of appearance such as bright shine with a soft tonal color. In this report, novel optical mechanisms of the characteristic blonde hair appearance are reported. Optical analyses of goniophotometric measurements were carried out to elucidate the mechanisms of strong reflections observed in blonde hairs. As a result, reflections with much higher intensity than those from the front surface of a fiber were confirmed to play important roles in the case of blonde hair fibers, and the intensities were found to vary with the cross-sectional shape of a fiber, the ellipticity (=minor axis/major axis). From light path simulation analyses, these strong reflections were verified to result from total reflection from the back surface of a fiber. Furthermore, since each hair fiber acts as a lens and/or a reflector, intricate reflection behaviors are suggested to occur as a consequence of the combination of light condensation and total reflection. [source] Synthesis of soluble poly(para -phenylene) with a long polymer chain: Characteristics of regioregular poly(1,4-phenylene)JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2008Itaru Natori Abstract Soluble poly(para -phenylene) having a long polymer chain (more than six repeat units) was synthesized with a tert -butyl end-group (t -PPP) and was found to have improved solubility and excellent optical properties. Poly(1,3-cyclohexadiene) (PCHD) consisting of only 1,4-cyclohexadiene (1,4-CHD) units was synthesized with a tert -butyl end-group (t -PCHD), and completely dehydrogenated to obtain t -PPP. This end-group effectively prevented the crystallization of t -PPP, and polymers containing up to 16 repeat units were soluble in tetrahydrofuran. Soluble t -PPP obtained had an ability to form a tough thin film prepared by spin-coating method. Optical analyses of t -PPP provided strong evidence for a linear polymer chain structure. A block copolymer of t -PPP and a soluble polyphenylene (PPH) was then synthesized, and the excellent optical properties were retained by this block copolymer along with its solubility. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5223,5231, 2008 [source] Polyvinyl-Locked versus Free Quaterthiophene: Effect of Spatial Constraints on the Electronic Properties of n -HexylquaterthiopheneCHEMPHYSCHEM, Issue 18 2007Manuela Melucci Dr. Abstract A soluble, low-weight fraction of poly(,-vinyl,,- n -hexyl-quaterthiophene), PT4Hex, having n -hexylquaterthiophenes as side-chain groups, is prepared by free-radical polymerization of ,-vinyl,,-n-hexyl-quaterthiophene and the corresponding properties compared to those of free di- n -hexylquaterthiophene (T4Hex). Optical analysis (absorption and emission) and X-ray diffraction data indicate that in the polyvinyl-locked architecture the quaterthiophene pendants adopt a cofacial arrangement with a mutual distance close enough for ,,, orbitals to overlap (,4 Å). As a consequence of the close chain packing, a shift of the reduction potential of about 0.5 V toward less negative values with respect to free T4Hex, is found for PT4Hex films. Due to its enhanced electron affinity, PT4Hex displays an electron-acceptor behavior when blended with alkylated and silylated quaterthiophenes acting as donors. [source] Techniques to measure the dry aeolian deposition of dust in arid and semi-arid landscapes: a comparative study in West NigerEARTH SURFACE PROCESSES AND LANDFORMS, Issue 2 2008Dirk Goossens Abstract Seven techniques designed to measure the dry aeolian deposition of dust on a desert surface were tested during field experiments in Niger, central-west Africa. Deposition fluxes were measured during eight periods of 3,4 days each. Experimental techniques tested were the MDCO (marble dust collector) method, the Frisbee method, the glass plate method (optical analysis of dust deposited on glass surfaces using particle imaging software), the soil surface method (deposition on a simulated desert floor) and the CAPYR (capteur pyramidal) method. Theoretical techniques tested were the inferential method and the combination method (gradient method extended with a deposition term for coarse dust particles). The results obtained by the MDCO, Frisbee, inferential and combination methods could be directly compared by converting the data to identical standard conditions (deposition on a water surface producing no resuspension). The results obtained by the other methods (glass plate, soil surface, CAPYR) were compared relatively. The study shows that the crude (unconverted) deposition fluxes of the five experimental techniques were similar, while the crude deposition fluxes calculated by the two theoretical techniques were substantially higher, of the order of four to five times as high as for the experimental techniques. Recalculation of the data to identical environmental conditions (the standard water surface) resulted in nearly identical deposition fluxes for the MDCO, Frisbee, inferential and combination techniques, although the latter two still had slightly higher values (but the differences remained small). The measurements illustrate the need to include a grain shape factor in theoretical dust deposition models. Without such a factor, theoretical models overestimate the deposition. The paper also discusses the advantages and disadvantages of the techniques tested. Copyright © 2007 John Wiley & Sons, Ltd. [source] Effect of the substrate temperature on the properties of the RF sputtered TiO2 thin filmsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 9 2010I. Ben Mbarek Abstract Titanium dioxide (TiO2) thin films were deposited by RF magnetron sputtering on glass and silicon substrates at different substrate temperatures (20, 100, 200 and 300 °C). The structural and morphological characteristics of the films were investigated by X ray Diffractometry (XRD) and Atomic Force Microscopy (AFM) while the optical properties of the films were studied by optical spectroscopy. It was shown that at room temperature, TiO2 films grown on glass were amorphous following the substrate structure. At higher temperatures, XRD detected only a nanocrystalline rutile TiO2 structure. This indicated that the transition temperature toward the most stable TiO2 phase was obtained from 100 °C and the crystallinity was enhanced at higher growth temperature. For TiO2 films grown on Si substrates, only a nanocrystalline anatase TiO2 structure was obtained at room temperature. At higher temperatures, we noticed the appearance of other secondary phases related to rutile, anatase and brookite structures. From AFM images, we noticed that at room temperature, the films were porous. With increasing the temperature, the structure of the films became crystallized showing a columnar structure. Film growth and structural properties were discussed in terms of the Thornton model. From optical analysis, the films were transparent with an indirect band gap and a refraction index which reached 3.09 eV and 2.7, respectively. The reflectance and transmittance spectra showed, not only that there was a little translation from UVB to UVA and near-visible range, but also a decrease of reflection with a temperature increase indicating that the films could be used as anti-reflection coatings. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Recent observations of AB Dor and interpretationASTRONOMISCHE NACHRICHTEN, Issue 4 2009E. Budding Abstract We use minimal empirical modelling techniques to interpret recent (2006,2007) photometry and spectroscopy of AB Dor. We compare, in particular, broadband (B and V) maculation effects with emission features in high-resolution Ca II K-line spectroscopy. We also compare emission effects in the Ca II Kand H, lines observed at different rotational phases. We refer to a broader multiwavelength campaign, of which these optical data were a part, involving X-ray and microwave observations to be published later. The broadband light curves are characterized by one outstanding macula, whereas the emission lines suggest 4 possible main chromospheric activity sites (,faculae'). These appear at a similar latitude and with comparable size to the main umbra, but there are significant displacements in longitude. However, one strong facular concentration near phase zero may have a physical relationship to the main macula. The derived longitudes of these features would have been affected by differential rotation operating over the several months between the spectroscopic and photometric observations, but the difference of at least ,30° between facula and umbra appears too great to allow their coincidence. The possibility of a large bipolar surface structure is considered, keeping in mind the bipolar character of solar activity centres: the activity of rapidly rotating cool stars being generally compared with that of the Sun, scaled up by a few orders of magnitude. Observed microwave activity may link to this same main photospheric and chromospheric centre picked up by the optical analysis. Characterization of macular and facular contributions in stellar activity sites would be improved with a closer timing of observations and higher signal to noise ratios in emission line data (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Continuous perfusion microfluidic cell culture array for high-throughput cell-based assaysBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2005Paul J. Hung Abstract We present for the first time a microfluidic cell culture array for long-term cellular monitoring. The 10 × 10 array could potentially assay 100 different cell-based experiments in parallel. The device was designed to integrate the processes used in typical cell culture experiments on a single self-contained microfluidic system. Major functions include repeated cell growth/passage cycles, reagent introduction, and real-time optical analysis. The single unit of the array consists of a circular microfluidic chamber, multiple narrow perfusion channels surrounding the main chamber, and four ports for fluidic access. Human carcinoma (HeLa) cells were cultured inside the device with continuous perfusion of medium at 37°C. The observed doubling time was 1.4 ± 0.1 days with a peak cell density of ,2.5*105 cells/cm2. Cell assay was demonstrated by monitoring the fluorescence localization of calcein AM from 1 min to 10 days after reagent introduction. Confluent cell cultures were passaged within the microfluidic chambers using trypsin and successfully regrown, suggesting a stable culture environment suitable for continuous operation. The cell culture array could offer a platform for a wide range of assays with applications in drug screening, bioinformatics, and quantitative cell biology. © 2004 Wiley Periodicals, Inc. [source] On the Tacticity of Polynorbornenes with 5,6- endo Pendant Groups That Contain Substituted Aryl ChromophoresCHEMISTRY - AN ASIAN JOURNAL, Issue 6 2007Wei-Yu Lin Abstract Two dimers and a series of polymers with 5,6- endo pendant aryl groups that contain different substituents at the para positions were synthesized. The conformation and stereochemistry of the dimers and polymers were determined by nonlinear optical analysis (EFISH) as well as UV/Vis and 13C,NMR spectroscopy. The chemical shifts of C7 for the polymers appeared as two peaks in the 13C,NMR spectra when the substituents are electron-withdrawing groups. The percentage decrease in the relative extinction coefficient of the polymers, ,d, was linearly related to the Hammett constant ,. Polynorbornenes with electron-withdrawing substituents may adopt isotactic stereochemistry with all pendant groups aligned in one direction. The nature of the interactions between neighboring chromophores may be one of the most important factors in directing the stereoregularity and conformation of these polymers. The corresponding polymers derived from the exo isomers appeared to be less stereoregular. [source] | ||||||||||||||||