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Infrared Imaging (infrared + imaging)
Selected AbstractsRaman and Infrared Imaging of Dynamic Polymer SystemsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2007Jack L. Koenig Abstract This work reviews principles of Raman and infrared imaging, as well as applications of the art to understand physiochemical phenomena in polymer systems. Image sequences may be assessed in terms of spatial or spectral changes that occur over time, either within a specific region or across the field of view. As such, the methods have enabled the analysis of diffusion and dissolution processes at polymer interfaces, drug release from polymer matrices, and structural transitions among others. Despite analytical limitations imposed by resolution (spectral or spatial) and sample preparation, Raman and infrared imaging are powerful tools for relating performance attributes to molecular-level characteristics. [source] Effect of Hormone Replacement Therapy on Bone Quality in Early Postmenopausal WomenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2003Ep Paschalis PhD Abstract HRT is an effective prophylaxis against postmenopausal bone loss. Infrared imaging of paired iliac crest biopsies obtained at baseline and after 2 years of HRT therapy demonstrate an effect on the mineral crystallinity and collagen cross-links that may affect bone quality. Several studies have demonstrated that hormonal replacement therapy (HRT) is an effective prophylaxis against postmenopausal bone loss, although the underlying mechanisms are still debated. Infrared spectroscopy has been used previously for analyzing bone mineral crystallinity and three-dimensional structures of collagen and other proteins. In the present study, the technique of Fourier transform infrared microscopic imaging (FTIRI) was used to investigate the effect of estrogen on bone quality (arbitrarily defined as mineral/matrix ratio, mineral crystallinity/maturity, and relative ratio of collagen cross-links [pyridinoline/deH-DHLNL]) at the ultrastructural level, in mineralized, thin tissue sections from double (before and after administration of HRT regimen; cyclic estrogen and progestogen [norethisterone acetate]) iliac crest biopsy specimens from 10 healthy, early postmenopausal women who were not on any medication with known influence on calcium metabolism. FTIRI allows the analysis of undemineralized thin tissue sections (each image analyzes a 400 × 400 ,m2 area with a spatial resolution of ,6.3 mm). For each bone quality variable considered, the after-treatment data exhibited an increase in the mean value, signifying definite changes in bone properties at the molecular level after HRT treatment. Furthermore, these findings are consistent with suppressed osteoclastic activity. [source] Infrared imaging with InAs/GaSb type-II superlatticesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 14 2006M. Walther Abstract InAs/GaSb short period superlattices (SLs) with broken gap typ-II band alignment are very well suited for the fabrication of high performance infrared camera systems for the second atmospheric window (3,5 µm). High resolution focal plane arrays for single- and dual-colour applications based on InAs/GaSb SLs have been fabricated. Those camera systems reveal excellent performance data which are comparable and even superior to state of the art thermal imaging systems. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] One-sided flame spread phenomena of a thermally thin composite cotton/fiberglass fabricFIRE AND MATERIALS, Issue 1 2005Julie Kleinhenz Abstract As an experimental necessity, past flame spread studies have relied on fast burning cellulosic papers. For the longer duration tests planned for the International Space Station a 50% fiberglass, 50% cotton composite fabric is better suited for the novel fuel feeding system in the compact hardware design of a current microgravity combustion experiment. The fabric's combustion characteristics in normal gravity include unexpected cases where a flame can be sustained on one side of the fuel. One-sided flames are smaller in size than their two-sided counterparts, and propagate at half the speed. Surface temperature distributions were measured using infrared imaging and indicated a high temperature region caused by the non-flammable fiberglass. Breaching the fiberglass matrix made it possible for the flame to transfer to the other side of the fuel, suggesting that the fiberglass matrix acts as a flame arrester. Copyright © 2004 John Wiley & Sons, Ltd. [source] Ecological Consequences of Ground Water Discharge to Delaware Bay, United StatesGROUND WATER, Issue 7 2004Douglas C. Miller Submarine ground water discharge to the ocean has the potential to create estuarine conditions near the point of discharge, thereby dramatically altering local benthic habitats and ecology. Aerial thermal infrared imaging along the southwestern margin of Delaware Bay indicated abundant discharge at Cape Henlopen, Delaware, adjacent to the Atlantic Ocean. On the sandflat there, we have documented low salinity in sedimentary pore waters within 20 m of the beachface that are associated with dense assemblages (in thousands per square meter) of a deep, burrow-dwelling polychaete worm, Marenzelleria viridis, otherwise regarded as a species characteristic of fresher, oligohaline conditions. Where present, M. viridis is a numerical and biomass dominant in a benthic community strikingly different from that in nearby nonseep locations. At Cape Henlopen, the ecological role of the ground water discharge appears to be a multifaceted one. Seeps are localized regions of significantly reduced salinity, stabilized temperature, increased nutrient flux, high microalgal abundance, and enhanced sediment stability. M. viridis feeds on sediment diatoms and may provide an important trophic linkage between microalgal growth fueled by nutrients associated with the discharging ground water and worm-feeding predators such as bottom fish or shorebirds common on the Cape Henlopen sandflat. Calculations based on our sampling suggest that nutrients supplied by the ground water substantially exceed what is needed to support benthic biomass and productivity estimated for this site. [source] The integration of thermal infrared imaging, discharge measurements and numerical simulation to quantify the relative contributions of freshwater inflows to small estuaries in Atlantic CanadaHYDROLOGICAL PROCESSES, Issue 20 2009Serban Danielescu Abstract Nutrient fluxes from developed catchments are often a significant factor in the declining water quality and ecological functioning in estuaries. Determining the relative contributions of surface water and groundwater discharge to nutrient-sensitive estuaries is required because these two pathways may be characterized by different nutrient concentrations and temporal variability, and may thus require different remedial actions. Quantifying the volumetric discharge of groundwater, which may occur via diffuse seepage or springs, remains a significant challenge. In this contribution, the total discharge of freshwater, including groundwater, to two small nutrient-sensitive estuaries in Prince Edward Island (Canada) is assessed using a unique combination of airborne thermal infrared imaging, direct discharge measurements in streams and shoreline springs, and numerical simulation of groundwater flow. The results of the thermal infrared surveys indicate that groundwater discharge occurs at discrete locations (springs) along the shoreline of both estuaries, which can be attributed to the fractured sandstone bedrock aquifer. The discharge measured at a sub-set of the springs correlates well with the area of the thermal signal attributed to each discharge location and this information was used to determine the total spring discharge to each estuary. Stream discharge is shown to be the largest volumetric contribution of freshwater to both estuaries (83% for Trout River estuary and 78% for McIntyre Creek estuary); however, groundwater discharge is significant at between 13% and 18% of the total discharge. Comparison of the results from catchment-scale groundwater flow models and the analysis of spring discharge suggest that diffuse seepage to both estuaries comprises only about 25% of the total groundwater discharge. The methods employed in this research provide a useful framework for determining the relative volumetric contributions of surface water and groundwater to small estuaries and the findings are expected to be relevant to other fractured sandstone coastal catchments in Atlantic Canada. Copyright © 2009 John Wiley & Sons, Ltd. [source] Bone material quality in transiliac bone biopsies of postmenopausal osteoporotic women after 3 years of strontium ranelate treatmentJOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2010Paul Roschger Abstract Strontium ranelate (SrR) is a relatively new treatment for osteoporosis. In this study we investigated its potential impact on human bone material quality in transiliac bone biopsies from postmenopausal osteoporotic women treated 3 years with calcium and vitamin D plus either 2,g SrR per day or placebo. Bone mineralization density distribution (BMDD), strontium (Sr) concentration, collagen cross-link ratio, and indentation modulus were analyzed by quantitative backscattered electron imaging, electron-induced X-ray fluorescence analysis, synchrotron radiation induced micro X-ray fluorescence elemental mapping, Fourier transform infrared imaging, and nanoindentation, respectively. The BMDD of SrR-treated patients was shifted to higher atomic numbers (Zmean +1.5%, p,<,.05 versus placebo). We observed Sr being preferentially incorporated in bone packets formed during SrR treatment up to 6% atom fraction [Sr/(Sr,+,Ca)] depending on the SrR serum levels of the individuals (correlation r,=,0.84, p,=,.018). Collagen cross-link ratio was preserved in SR-treated bone. The indentation modulus was significantly decreased in younger versus older bone packets for both placebo- (,20.5%, p,<,.0001) and SrR-treated individuals (,24.3%, p,<,.001), whereas no differences were found between the treatment groups. In conclusion, our findings indicate that after SrR treatment, Sr is heterogeneously distributed in bone and preferentially present in bone packets formed during treatment. The effect of SrR on BMDD seems to be due mainly to the uptake of Sr and not to changes in bone calcium content. Taken together, these data provide evidence that the investigated bone quality determinants at tissue level were preserved in postmenopausal osteoporotic women after 3-year treatment with 2,g SrR per day plus calcium and vitamin D. © 2010 American Society for Bone and Mineral Research [source] Bone Material Properties in Trabecular Bone From Human Iliac Crest Biopsies After 3- and 5-Year Treatment With Risedronate,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2006Erich Durchschlag Abstract Long-term effects of risedronate on bone mineral maturity/crystallinity and collagen cross-link ratio in triple iliac crest biopsies of osteoporotic women were evaluated. In this double-blinded study, 3- and 5-year treatment with risedronate arrested the tissue aging encountered in untreated osteoporosis and in osteoporosis treated with other antiresorptives. This effect may be contributing to risedronate's antifracture efficacy. Introduction: Risedronate is widely used in the treatment of osteoporosis. It reduces bone turnover, increases BMD, and decreases fracture risk. To date, there are no data available on the long-term effects of risedronate on bone material properties in humans. Materials and Methods: Osteoporotic women enrolled in the VERT-NA trial received either risedronate (5 mg/day, orally) or placebo for up to 5 years. All subjects received calcium. They also received vitamin D supplementation if deficient at baseline. Triple iliac crest biopsies were collected from a subset of these subjects at baseline, 3 years, and 5 years. Mineral maturity/crystallinity and collagen cross-link ratio was measured in these biopsies using Fourier transform infrared imaging. Results: Patients that received placebo exhibited increased mineral maturity/crystallinity and collagen cross-link ratio after 3 and 5 years compared with baseline values. On the contrary, patients that received risedronate retained baseline values in both bone material indices throughout. A more spatially detailed analysis revealed that this was achieved mainly through beneficial effects on active bone-forming areas. Surprisingly, patients that received risedronate achieved premenopausal values at bone-forming areas in both indices after 5 years of treatment. Conclusion: Long-term treatment with risedronate affects bone material properties (mineral maturity/crystallinity and collagen cross-link ratio) and arrests the tissue aging apparent in untreated osteoporosis. These changes at the material level of the bone matrix may contribute to risedronate's rapid and sustained antifracture efficacy in osteoporotic patients. [source] Bone Fragility and Collagen Cross-Links,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2004Eleftherios P Paschalis Abstract Infrared imaging analysis of iliac crest biopsy specimens from patients with osteoporotic and multiple spontaneous fractures shows significant differences in the spatial variation of the nonreducible:reducible collagen cross-links at bone-forming trabecular surfaces compared with normal bone. Introduction: Although the role of BMC and bone mineral quality in determining fracture risk has been extensively studied, considerably less attention has been paid to the quality of collagen in fragile bone. Materials and Methods: In this study, the technique of Fourier transform infrared imaging (FTIRI) was used to determine the ratio of nonreducible:reducible cross-links, in 2- to 4-,m-thick sections, from human iliac crest biopsy specimens (N = 27) at bone-forming trabecular surfaces. The biopsy specimens were obtained from patients that had been diagnosed as high- or low-turnover osteoporosis, as well as premenopausal women <40 years of age, with normal BMD and biochemistry, who suffered multiple spontaneous fractures. The obtained values were compared with previously published analyses of trabecular bone from normal non-osteoporotic subjects (N = 14, 6 males and 8 females; age range, 51,70 years). Results and Conclusions: Collagen cross-links distribution within the first 50 ,m at forming trabecular surfaces in patients with fragile bone was markedly different compared with normal bone. [source] Bone Mineral and Collagen Quality in Humeri of Ovariectomized Cynomolgus Monkeys Given rhPTH(1,34) for 18 MonthsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2003Eleftherios P Paschalis Abstract A recent study of ovariectomized monkeys, treated with recombinant human parathyroid hormone (rhPTH)(1,34) at 1 or 5 mg/kg/day for 18 months or for 12 months followed by 6 months withdrawal from treatment, showed significant differences in the geometry and histomorphometry of cortical bone of the midshaft humerus. To determine the extent to which the rapid bone turnover and cortical porosity induced by rhPTH(1,34) in ovariectomized monkeys modified mineral content, mineral crystal maturity and collagen maturity (cross-link distribution) in the cortical periosteal and endosteal regions, cross-sections of the cortical bone of the mid-humerus, were examined using Fourier transform infrared imaging (FTIRI). FTIRI analyses demonstrated that rhPTH(1,34) altered bone mineral and collagen properties in a dose-dependent manner. Mineral crystal maturity and collagen cross-link ratio (pyridinoline/dehydro-dihydroxylysinonorleucine) on both endosteal and periosteal surfaces decreased relative to ovariectomized animals, consistent with new bone formation. These changes were partially sustained after withdrawal of the higher dose of rhPTH(1,34), suggesting a prolonged after-effect on bone properties for at least two bone remodeling cycles. In conclusion, treatment of ovariectomized monkeys with rhPTH(1,34) had significant effects on cortical bone mineral-to-matrix ratio, mineral crystal maturity, and collagen cross-link ratio. These were fully reversible when the 1-,g rhPTH(1,34) treatment was withdrawn, but only partially reversed when the 5-,g rhPTH(1,34) dose was withdrawn. [source] Raman and Infrared Imaging of Dynamic Polymer SystemsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2007Jack L. Koenig Abstract This work reviews principles of Raman and infrared imaging, as well as applications of the art to understand physiochemical phenomena in polymer systems. Image sequences may be assessed in terms of spatial or spectral changes that occur over time, either within a specific region or across the field of view. As such, the methods have enabled the analysis of diffusion and dissolution processes at polymer interfaces, drug release from polymer matrices, and structural transitions among others. Despite analytical limitations imposed by resolution (spectral or spatial) and sample preparation, Raman and infrared imaging are powerful tools for relating performance attributes to molecular-level characteristics. [source] GaN HEMT thermal behavior and implications for reliability testing and analysisPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008Daniel S. Green Abstract GaN HEMT reliability evaluation in a typical Arrhenius manner requires establishing peak junction temperature for a particular stress condition. Several new techniques have yielded promising results toward establishing peak temperature for these devices in combination with detailed physical modeling, particularly micro-Raman imaging. This paper compares results from finite element modeling to measurements by infrared imaging and micro-Raman imaging. The limitations of IR imaging were confirmed similar to earlier reports. Two techniques for establishing temperature from micro-Raman measurements were used to reveal excellent correlation to the model, and also provide insight into the relationship between temperature and structural change in the device. Temperature modeling data is reported for base plate temperature from 85°C to 250°C for practical GaN HEMT devices. Implications of the measurements for GaN HEMT reliability stress testing and analysis will be discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Detecting sub-surface cracking in laminated membranes using infrared imagingPOLYMER COMPOSITES, Issue 6 2001Thomas J. Mackin This paper presents a new experimental method that utilizes the thermoelastic effect to detect sub-surface cracks in a laminated polymer membrane. A highly accurate infrared camera is used to measure the thermoelastic and dissipational heat signatures associated with bi-axial fatigue loading of membranes. Changes in these thermal signatures arise whenever cracks form in any layer of the laminate, including fully embedded layers, thereby providing a novel method for experimentally measuring the initiation and growth of damage in sub-surface layers. The proposed method is illustrated using a model 3-layer system of EVOH sandwiched between two polyurethane layers. Bi-axial fatigue loading was used to initiate cracking in the central EVOH layer without damaging the outer polyurethane layers. Cracking in the central layer resulted in a distinct thermal signature that was plainly visible using the proposed method. [source] The FIRST radio survey: Panchromatic properties of FIRST radio sources identified in the Boötes and Cetus fieldsASTRONOMISCHE NACHRICHTEN, Issue 1 2009K. El Bouchefry Abstract In this paper the availability of multi-wavelength optical/infrared information of FIRST (Faint Images of the Radio Sky at 20 cm) radio sources counterparts over ,9.2 deg2 in the Boötes field and ,2.4 deg2 in the Cetus field is exploited to infer the physical properties of the faint radio population. The radio sources optically identified have been divided into resolved galaxies and stellar-like objects finding that the faint radio population is mainly composed of early-type galaxies with very red colour (Bw , R , 4.6). A total number of 57 counterparts of FIRST radio sources have extremely red colour (R , K , 5). Photometric redshift from Hyperz implies that the Extremely Red Objects (EROs) counterparts to FIRST radio sources are mostly located in the range z = 0.7,2, with the bulk of the population at z , 1. Taking advantage of the near infrared imaging with FLAMEX (FLAMINGOS Extragalactic Infrared Survey), the EROs counterparts to FIRST radio sources are separated into passively-evolving and dusty star-forming galaxies using their RJK colours; the relatively blue J , K of these galaxies suggest that most are old elliptical galaxies (18/25) rather than dusty starburst galaxies (7/25). A total of 15 Distant Red Galaxy (DRGs) have been identified as counterparts to FIRST radio sources in the Cetus field and 3 DRGs in the Boötes field with J , K > 2.3 (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Differential effects of ageing on foveal and peripheral colour visionACTA OPHTHALMOLOGICA, Issue 2009F RAUSCHER Purpose Colour sensitivity was assessed to establish aging effects both at the fovea and 6 deg away from fixation, in each of the four quadrants. Methods 65 normal healthy subjects (from 20 to 80 years of age) took part in the study. All subjects had Visual Acuity (VA) of 6/6 or better. Fixation accuracy was monitored using infrared imaging of the pupil and the tests were carried out on the P_SCAN system. Target size was adjusted for parafoveal locations to account for retinal and cortical magnification. Yellow-blue (YB) and red-green (RG) colour discrimination was assessed using the CAD (colour assessment and diagnosis) test (http://www.caa.co.uk/docs/33/200904.pdf). Results RG and YB colour thresholds were analysed separately for all five locations tested and showed no significant effect with ageing below the age of 60 years. Two age bands were formed based on statistical analysis (20-59.9 and 60-79.9). The decline in performance with age was more rapid at the fovea and exhibited a steeper gradient when compared with results in the periphery for both RG and YB discrimination. Foveal YB discrimination showed the largest ageing effect. No significant difference was found between the four parafoveal locations. YB discrimination at the fovea also exhibited the largest inter-subject variability. Conclusion These findings may have clinical significance in the very early detection of disease processes that remain subclinical in many subjects. Differences between foveal and peripheral locations help to differentiate between the normal effects of ageing and disease. For example, higher foveal and normal peripheral YB thresholds in normal subjects from high peripheral thresholds in early glaucomatous subjects. [source] | |||||||||||||||||||