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Applied Spectroscopy

Shun Muroga, Yuta Hikima, Masahiro Ohshima
During melt processing, the moisture inside polylactide (PLA) easily induces hydrolysis, which deteriorates the mechanical and thermal properties of the product. The state of dryness of resin pellets must be monitored to prevent PLA hydrolysis. In this study, near-infrared (NIR) spectroscopy was applied to measure water content in PLA. In addition, the shape of the NIR spectrum is also affected by crystallization, which could lead to a reduction in the accuracy of evaluating the water content. The objective of this research is to construct a robust model for estimating the water content with varying dispersive extents of crystallization...
December 12, 2016: Applied Spectroscopy
Letícia Bonfante Sicchieri, Andrea Moreira Monteiro, Antônio Martins Figueiredo Neto, Laércio Gomes, Lilia Coronato Courrol
Standard lipoprotein measurements of triglycerides, total cholesterol, low-density lipoproteins (LDL), and high-density lipoproteins (HDL) fail to identify many lipoprotein abnormalities that contribute to cardiovascular heart diseases (CHD). Studies suggested that the presence of CHD is more strongly associated with the HDL subspecies than with total HDL cholesterol levels. The HDL particles can be collected in at least three subfractions, the HDL2b, HDL2a, and HDL3. More specifically, atherosclerosis is associated with low levels of HDL2...
December 12, 2016: Applied Spectroscopy
Patrick D Barnett, K Alicia Strange, S Michael Angel
This work describes a method of applying the Fourier transform to the two-dimensional Fizeau fringe patterns generated by the spatial heterodyne Raman spectrometer (SHRS), a dispersive interferometer, to correct the effects of certain types of optical alignment errors. In the SHRS, certain types of optical misalignments result in wavelength-dependent and wavelength-independent rotations of the fringe pattern on the detector. We describe here a simple correction technique that can be used in post-processing, by applying the Fourier transform in a row-by-row manner...
December 12, 2016: Applied Spectroscopy
Daouda K Diop, Lionel Simonot, Juan Martínez-García, Mathieu Hébert, Yaya Lefkir, Grégory Abadias, Philippe Guérin, David Babonneau, Nathalie Destouches
Giving paper and polymer photochromic properties under laser irradiation is challenging due to the low resistance of these materials to heat, their flexibility, and their possibly irregular structure. However, we could successfully deposit TiO2/Ag/TiO2 layers stacking on flexible white glossy paper and transparent polyethylene terephalate (PET) substrates using a reactive magnetron sputtering technique, and tailor coloration changes after laser irradiation, alternating visible and ultraviolet (UV) wavelengths...
December 12, 2016: Applied Spectroscopy
Carlton Farley, Aschalew Kassu, Nayana Bose, Armitra Jackson-Davis, Judith Boateng, Paul Ruffin, Anup Sharma
A short distance standoff Raman technique is demonstrated for detecting economically motivated adulteration (EMA) in extra virgin olive oil (EVOO). Using a portable Raman spectrometer operating with a 785 nm laser and a 2-in. refracting telescope, adulteration of olive oil with grapeseed oil and canola oil is detected between 1% and 100% at a minimum concentration of 2.5% from a distance of 15 cm and at a minimum concentration of 5% from a distance of 1 m. The technique involves correlating the intensity ratios of prominent Raman bands of edible oils at 1254, 1657, and 1441 cm(-1) to the degree of adulteration...
December 12, 2016: Applied Spectroscopy
Verena Wiedemair, Sophia Mayr, Daniel S Wimmer, Eva Maria Köck, Simon Penner, Andreas Kerstan, Patricia-Anca Steinmassl, Herbert Dumfahrt, Christian W Huck
Water absorbed to poly(methyl methacrylate) (PMMA)-based CAD/CAM (computer-assisted design/computer-assisted manufacturing) prosthodontics can alter their properties including hardness and stability. In the present contribution, water absorption and desorption kinetics under defined experimental conditions were monitored employing several supplementary and advanced Fourier transform infrared (FT-IR) spectroscopic techniques in combination with multivariate analysis (MVA). In this synergistic vibrational spectroscopic multimethod approach, first a novel near-infrared (NIR) diffuse fiber optic probe reflection spectroscopic method was established for time-resolved analysis of water uptake within seven days under controlled conditions...
December 12, 2016: Applied Spectroscopy
Rui-Qiong Luo, Fang Wei, Shu-Shi Huang, Yue-Ming Jiang, Shan-Lei Zhang, Wen-Qing Mo, Hong Liu, Xi Rong
The examination of insulin (Ins) exocytosis at the single-cell level by conventional methods, such as electrophysiological approaches, total internal reflection imaging, and two-photon imaging technology, often requires an invasive microelectrode puncture or label. In this study, high concentrations of glucose and potassium chloride were used to stimulate β cell Ins exocytosis, while low concentrations of glucose and calcium channel blockers served as the blank and negative control, respectively. Laser tweezers Raman spectroscopy (LTRS) was used to capture the possible Raman scattering signal from a local zone outside of the cell edge...
December 9, 2016: Applied Spectroscopy
Peter B Skou, Thilo A Berg, Stina D Aunsbjerg, Dorrit Thaysen, Morten A Rasmussen, Frans van den Berg
Reuse of process water in dairy ingredient production-and food processing in general-opens the possibility for sustainable water regimes. Membrane filtration processes are an attractive source of process-water recovery since the technology is already utilized in the dairy industry and its use is expected to grow considerably. At Arla Foods Ingredients (AFI), permeate from a reverse osmosis polisher filtration unit is sought to be reused as process water, replacing the intake of potable water. However, as for all dairy and food producers, the process-water quality must be monitored continuously to ensure food safety...
November 29, 2016: Applied Spectroscopy
Kyle T Hufziger, Sergei V Bykov, Sanford A Asher
We constructed the first deep ultraviolet (UV) Raman standoff wide-field imaging spectrometer. Our novel deep UV imaging spectrometer utilizes a photonic crystal to select Raman spectral regions for detection. The photonic crystal is composed of highly charged, monodisperse 35.5 ± 2.9 nm silica nanoparticles that self-assemble in solution to produce a face centered cubic crystalline colloidal array that Bragg diffracts a narrow ∼1.0 nm full width at half-maximum (FWHM) UV spectral region. We utilize this photonic crystal to select and image two different spectral regions containing resonance Raman bands of pentaerythritol tetranitrate (PETN) and NH4NO3 (AN)...
November 28, 2016: Applied Spectroscopy
Cynthia Hanson, Michael Sieverts, Elizabeth Vargis
Raman spectroscopy has been used for decades to detect and identify biological substances as it provides specific molecular information. Spectra collected from biological samples are often complex, requiring the aid of data truncation techniques such as principal component analysis (PCA) and multivariate classification methods. Classification results depend on the proper selection of principal components (PCs) and how PCA is performed (scaling and/or centering). There are also guidelines for choosing the optimal number of PCs such as a scree plot, Kaiser criterion, or cumulative percent variance...
November 25, 2016: Applied Spectroscopy
Jianhua Gao, Zhongzhu Liang, Jingqiu Liang, Weibiao Wang, Jinguang Lü, Yuxin Qin
Based on the basic configuration and interference principle of a static step-mirror-based Fourier transform spectrometer, an image segmentation method is proposed to obtain a one-dimensional interferogram. The direct current component of the interferogram is fit using the least squares (LS) method and is subsequently removed. An empirical-mode decomposition-method-based high-pass filter is constructed to denoise the spectrum and enhance the spectral resolution simultaneously. Several experiments were performed and the spectrum is reconstructed based on these methods...
November 23, 2016: Applied Spectroscopy
Weiwei Zhang, Guoyao Wang, Greg W Baxter, Stephen F Collins
A systematic study was performed on the temperature-dependent fluorescence of (Ba,Sr)2SiO4:Eu(2+) The barycenter and extended intensity ratio techniques were proposed to characterize the broadband fluorescence spectra. These techniques and other known methods (listed below) were employed and compared in the fluorescent temperature sensing experiment. Multiple sensing functions were obtained using the behaviors of: (1) the barycenter location of the emission band; (2) the emission bandwidth; and (3) the ratio of intensities at different wavelengths in the emission band, respectively...
November 22, 2016: Applied Spectroscopy
Nirmal Lamsal, S Michael Angel
In earlier works, we demonstrated a high-resolution spatial heterodyne Raman spectrometer (SHRS) for deep-ultraviolet (UV) Raman measurements, and showed its ability to measure UV light-sensitive compounds using a large laser spot size. We recently modified the SHRS by replacing the cube beam splitter (BS) with a custom plate beam splitter with higher light transmission, an optimized reflectance/transmission ratio, higher surface flatness, and better refractive index homogeneity than the cube beam splitter...
November 22, 2016: Applied Spectroscopy
Taixia Wu, Guanghua Li, Zehua Yang, Hongming Zhang, Yong Lei, Nan Wang, Lifu Zhang
Spectral analysis is one of the main non-destructive techniques used to examine cultural relics. Hyperspectral imaging technology, especially on the shortwave infrared (SWIR) band, can clearly extract information from paintings, such as color, pigment composition, damage characteristics, and painting techniques. All of these characteristics have significant scientific and practical value in the study of ancient paintings and other relics and in their protection and restoration. In this study, an ancient painting, numbered Gu-6541, which had been found in the Forbidden City, served as a sample...
November 21, 2016: Applied Spectroscopy
Andrew P Storey, Steven J Ray, Volker Hoffmann, Maxim Voronov, Carsten Engelhard, Wolfgang Buscher, Gary M Hieftje
Glow discharges have long been used for depth profiling and bulk analysis of solid samples. In addition, over the past decade, several methods of obtaining lateral surface elemental distributions have been introduced, each with its own strengths and weaknesses. Challenges for each of these techniques are acceptable optical throughput and added instrumental complexity. Here, these problems are addressed with a tilting-filter instrument. A pulsed glow discharge is coupled to an optical system comprising an adjustable-angle tilting filter, collimating and imaging lenses, and a gated, intensified charge-coupled device (CCD) camera, which together provide surface elemental mapping of solid samples...
November 21, 2016: Applied Spectroscopy
Mihaela Antonina Calin, Sorin Viorel Parasca, Marian Romeo Calin, Emil Petrescu
Skin texture has become an important issue in recent research with applications in the cosmetic industry and medicine. In this paper, we analyzed the dependence of skin texture features on wavelength as well as on different parameters (age and gender) of human participants using grey-level co-occurrence matrix and hyperspectral imaging technique for a more accurate quantitative assessment of the aging process. A total of 42 healthy participants (men and women; age range, 20-70 years) was enrolled in this study...
November 21, 2016: Applied Spectroscopy
Vitor S Zanuto, Otávio A Capeloto, Marcelo Sandrini, Luis C Malacarne, Nelson G C Astrath, Stephen E Bialkowski
Recent improvements in the modeling of photo-induced thermo-optical-mechanical effects have broadened the application of photothermal techniques to a large class of solids and fluids. During laser excitation, changes in optical reflectivity due to temperature variation may affect the photothermal signal. In this study, the influence of the reflectivity change due to heating is analyzed for two pump-probe photothermal techniques, thermal lens and thermal mirror. A linear equation for the temperature dependence of the reflectivity is derived, and the solution is tested using optical properties of semi-transparent and opaque materials...
November 18, 2016: Applied Spectroscopy
Zheming Li, Joakim Rosell, Marcus Aldén, Mattias Richter
Spatially and temporally resolved measurements are of great importance in turbulent premixed flame studies, especially when investigating rapid processes such as when flame local extinction, re-ignition, or flashback occur in a reacting flow. Here, an experimental approach for simultaneously probing two different species at high frame rates (50 kHz) is presented by employing a multi-YAG laser system. The laser radiation at 355 nm generated by a multi-YAG laser system was split into two beam paths: one beam for exciting formaldehyde and the other for pumping an optical parametric oscillator (OPO)...
November 18, 2016: Applied Spectroscopy
Marta B Lopes, Cecília R C Calado, Mário A T Figueiredo, José M Bioucas-Dias
The monitoring of biopharmaceutical products using Fourier transform infrared (FT-IR) spectroscopy relies on calibration techniques involving the acquisition of spectra of bioprocess samples along the process. The most commonly used method for that purpose is partial least squares (PLS) regression, under the assumption that a linear model is valid. Despite being successful in the presence of small nonlinearities, linear methods may fail in the presence of strong nonlinearities. This paper studies the potential usefulness of nonlinear regression methods for predicting, from in situ near-infrared (NIR) and mid-infrared (MIR) spectra acquired in high-throughput mode, biomass and plasmid concentrations in Escherichia coli DH5-α cultures producing the plasmid model pVAX-LacZ...
November 16, 2016: Applied Spectroscopy
Mika Ishigaki, Akihito Nakanishi, Tomohisa Hasunuma, Akihiko Kondo, Tetsu Morishima, Toshiaki Okuno, Yukihiro Ozaki
In the present study, the high-speed quantitative evaluation of glycogen concentration accumulated in bioethanol feedstock Synechocystis sp. PCC6803 was performed using a near-infrared (NIR) imaging system with a hyperspectral NIR spectral camera named Compovision. The NIR imaging system has a feature for high-speed and wide area monitoring and the two-dimensional scanning speed is almost 100 times faster than the general NIR imaging systems for the same pixel size. For the quantitative analysis of glycogen concentration, partial least squares regression (PLSR) and moving window PLSR (MWPLSR) were performed with the information of glycogen concentration measured by high performance liquid chromatography (HPLC) and the calibration curves for the concentration within the Synechocystis sp...
November 16, 2016: Applied Spectroscopy
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