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Reffner, John A., and William T. Wihlborg. "Microanalysis of Asbestos Fibers by Ft-IR Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (1990): 298–99. http://dx.doi.org/10.1017/s0424820100135095.
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The identification of asbestos fibers in bulk or airborne samples can be made by Fourier transform infrared (FT-IR) microscopy. Since asbestos fibers have been shown to be a health hazard, it is important to identify their presence in environmental samples. Asbestos fibers require both chemical and morphological data for their identification. This FT-IR microscopical method uses light microscopy for morphological and infrared spectroscopy for chemical identity of microscopic fibers. For the six minerals defined by the EPA as asbestos, the infrared spectral analysis can be made on the same sample preparations that are used for polarized light microscopy(PLM) or phase contrast microscopy (PCM) counting. In this study, the detection limit for asbestos fibers in airborne samples was 2 × 20μm (˜˜240pg).The infrared spectra of microscopic fiber bundles of standard asbestos minerals were obtained using an IRμS™ infrared microspectrometer. Spectra were collected within the range of 4000 to 600 cm-1 (2.4 to 16.7 μm), at a spectral resolution of either 2 or 4 cm-1.
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Carlton, R. A. "Microscopy in Pharmaceutical Development." Microscopy and Microanalysis 4, S2 (1998): 478–79. http://dx.doi.org/10.1017/s1431927600022510.
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Many different microscopic techniques are utilized in the development of new pharmaceuticals. For that reason, pharmaceutical companies have supported microscopy and microscopists even in the face of retrenchments in many other industries. Microscopy has the following three major uses in pharmaceutical development: 1) solid-state characterization of drug substance; 2) particle size analysis; 3) contaminant identification. Microscopy is also an important component of the study of the biological activity of drugs but that subject will not be discussed here.The analysis of the solid-state properties of new drug candidates is probably the most important and challenging subject of study for pharmaceutical microscopists.1 The primary objective of these studies is identification of the most suitable solid-state form (i.e. polymorph, solvate, hydrate) of the drug substance for development. Polarized light microscopy (PLM), thermal microscopy (TM), infrared microspectroscopy (IR), and Raman microspectroscopy (RM) are all utilized in these studies. Both PLM and TM are used to discover new polymorphs and solvates of the chemical.
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Millette, J. R., P. Few, and T. J. Hopen. "Microscopical Examination of Indoor Dusts." Microscopy and Microanalysis 4, S2 (1998): 476–77. http://dx.doi.org/10.1017/s1431927600022509.
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Several case studies are shown as examples of the results of analyses using various microscopical instruments to characterize the particles in building dusts. Characterizing the particles and identifying possible sources of particles in dusts are often important parts of solving indoor indoor air quality (IAQ) and environmental problems. Samples of the dust particles can be collected by filtering the air with cassette air filters or by gathering the dust that has accumulated on surfaces. Depending on the size and types of particles in the dust either polarized light microscopy (PLM), scanning electron microscopy with x-ray analysis (SEM/EDS), analytical transmission electron microscopy (ATEM) or Fourier transform infrared microspectroscopy (FTIR) may be used solely or in combination. PLM can characterize most of the common dust particle in residential and commercial buildings. SEM/EDS is helpful in identifying metal particles and when used in the backscatter electron mode, a large number of particles can be surveyed and those containing heavy metals such as lead and cadmium can be identified quickly.
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Park, J. I. "Complementary Analysis Using Polarized Light and Scanning Electron Microscopy in the Determination of Sulfate Attack on Concrete." Microscopy and Microanalysis 3, S2 (1997): 759–60. http://dx.doi.org/10.1017/s1431927600010680.
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A high water to cement ratio in concrete produces excessive porosity in the paste, thereby increasing the concrete’s susceptibility to sulfate attack and subsequent premature deterioration. Widely used as a building material, concrete experiences physical and chemical deterioration whose extent and nature may be determined by polarized light microscopy (PLM) and scanning electron microscopy (SEM). New software innovations allow exact image relocation in PLM and SEM, thereby producing complementary information which aids in analyst recognition and increases the effectiveness of each analytical technique.Although overlapping information may be derived using both PLM and SEM, each technique has inherent advantages and disadvantages which complement the other. The advantages of PLM include a color image, good low magnification resolution providing a bridge between macro/micro analysis, and the ability to distinguish polymorphs and materials of nearly identical composition (e.g., solid-solution series components). Disadvantages of PLM include limited high magnification potential, mineralogical identification based on the analyst’s knowledge of optics, and the need for photographic attachments.
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Caamaño, J. N., M. Catalá, R. Romaguera, et al. "257 DETECTION OF MICROTUBULES BY POLARIZED LIGHT MICROSCOPY IN SHEEP AND GOAT OOCYTES." Reproduction, Fertility and Development 23, no. 1 (2011): 226. http://dx.doi.org/10.1071/rdv23n1ab257.
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The meiotic spindle in the oocyte is composed of microtubules and plays a key role in normal chromosome alignment and segregation during meiosis. In oocytes from farm animals, the meiotic spindle cannot be detected by conventional light microscopy due to the characteristic of their cytoplasm. Conventional methods to image the meiotic spindle rely on fixation of the oocytes. Polarized light microscopy (PLM) allows noninvasive evaluation of the meiotic spindle of metaphase oocytes. The aim of this study was to assess the efficiency of polarized light microscopy to detect microtubule-polymerized protein within in vitro matured prepubertal sheep and goat oocytes. We carried out 2 studies. In the first one, cumulus–oocyte complexes from slaughterhouse sheep ovaries were matured in vitro for 27 h. After in vitro maturation, oocytes (n = 77) were denuded of cumulus cells and placed individually in 10-μL drops of TCM-199-HEPES-BSA in a glass Petri dish. Polarized light microscopy was used to detect the presence of polymerized protein, which could be associated with the forming of a meiotic spindle. To confirm the presence of the polymerized protein and the meiotic spindle, each individual oocyte was subjected to immunostaining and chromatin detection as described by (Morató et al. 2008 Mol. Reprod. Dev. 75, 191–201). The experiment was replicated 4 times. The correlation analysis was performed using the Proc Corr procedure of SAS. There was a positive correlation (r = 0.87; P < 0.001) between the signal obtained by PLM and the presence of microtubule-polymerized protein as confirmed by immunostaining. A positive PLM signal was detected in 87.0% of the oocytes, and 69.0% of the oocytes reached the metaphase II (MII) stage after in vitro maturation. A barrel-shaped spindle was observed in 77.3% of the MII oocytes. In the second study, we performed a similar experiment but used goat oocytes. A total of 78 oocytes were used, and PLM and immunostaining were performed in each individual oocyte as it was described with sheep oocytes. There was also a positive correlation (r = 1; P < 0.001) between the signal obtained by PLM and the presence of microtubule-polymerized protein. A positive PLM signal was detected in 98.7% of the oocytes, and 80.7% of the oocytes reached the MII stage after in vitro maturation. A barrel-shaped spindle was observed in 92.0% of the MII oocytes. These results indicate that PLM is an efficient system to detect polymerized protein in in vitro matured sheep and goat oocytes. This work was supported by the following grant: INIA: RZ2007-00013-00-00. M. Muñoz and D. Martín are sponsored by RYC08-03454 and PTA2007-0268-I, respectively.
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Zhang, Su Feng, and Chun Lei Kang. "Crystal Structure Analysis on Aramid Fiber/Fibrids and Paper by Polarized Light Microscopy." Key Engineering Materials 531-532 (December 2012): 636–39. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.636.
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The crystal structure of aramid fibers is highly orientated. The structure of aramid fibers with various manufacturing processes and aramid paper sheets were analyzed and observed by using polarized light microscope (PLM). The change and its law of aramid fiber crystal structure in such processes as aramid fiber mamufaturing of aramid fiber/fibrids, forming of aramid paper sheets, and heat treatment were analysed. The relationship between the structural feature of aramid fibers and the performance of aramid paper was also discussed.
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Assis, S., A. Keenleyside, and A. L. Santos. "Beyond the visible world: the role of microscopy in the study of past human conditions." Microscopy and Microanalysis 19, S4 (2013): 41–42. http://dx.doi.org/10.1017/s1431927613000822.
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Paleopathology, summarily defined as the study of past diseases, has on the differential diagnosis a major challenge. Histological techniques offered the possibility to look inside the microstructure of both normal and abnormal body tissues to diagnose diseases that affected past populations, leading to the development of a new field of research - paleohistology or paleohistopathology. However, and contrary to paleopathology whose journey is well-established, in paleohistopathology there are many gaps that need to be filled. This occurrence is probably the result of a nonsystematic and non-standardized approach to the microscopic study of skeletal abnormalities, especially those of infectious origin involving periosteal new bone formation (PNBF). The aims of this work were: (1) to search for differences in the microstructure of PNBF with regard to the cause of death of the individual; (2) to infer differences between the macroscopic and microscopic proprieties of bone lesions, and (3) to ascertain the impact of diagenetic changes in the bone microstructure. For histological examination under transmitted and polarized light, a total of 34 dry bone specimens: 26 belonging to 23 individuals from the Human Identified Skeletal Collection from the Bocage Museum (Lisbon, Portugal), and eight from archaeological skeletons were prepared. The documented bone samples were collected from individuals who died from tuberculosis-TB (Group 1), non-TB infectious diseases (Group 2), and conditions other than those of TB and non-TB infectious origin (Group 3).With regard to the diagnosis of pathological conditions, differences in the microstructure of PNBF were seen between Group 1 and Group 2 of cause of death and within groups. Multiple layers of “appositional bone” enclosing numerous primary vascular canals were the pattern most commonly observed (n=4) in the samples from Group 1. This type of PNBF seems to mimic the appositional growth that characterizes the modeling process of the periosteal and endosteal membranes (PEM) during rapid growth periods. An abnormal stimulation of growth factors, especially of the vascular endothelial growth factor (VEGF) may eventually explain the extensive hypervascularization observed (Fig. 1 A-B). Periosteal lesions on ribs are normally associated with pulmonary infection (e.g. TB) disseminated from the lungs (via pleura) to the ribs. However, three samples (one from Group 1, two from Group 2) presented a microstructure compatible with subperiosteal hematomas (Fig. 1 C-D). Repetitive microtrauma (e.g. chest wall vibration) that causes detachment of the periosteum may have leaded to subperiosteal bleeding and hematoma formation. These observations suggest that beyond pulmonary diseases other mechanisms may stimulate PNBF on the visceral surface of ribs. Histological analysis was also fundamental in the description and characterization of bone changes. For example, of the five samples with “consolidated” fracture callus, only two presented a truly mature and remodeled microstructure. This means that the outer surface of a bone lesion may not give a complete picture of the tissues response (Fig. 2 A-B). In spite of the good preservation of some bone samples, massive diagenetic changes due to the action of bacteria and fungi were observed at microscopic level. This clearly suggests that gross inspection is not a good measure of the bone tissue quality. In contrast, microscopy is essential to differentiate between pseudopathology and physiological or pathological signs.Microscopy revealed surprising results that reinforce the pertinence of applying histological techniques in the description and diagnosis of bone changes in human remains.This research was supported by Fundação para a Ciência e Tecnologia, Portugal [SFRH/BD/36739/2007, Sandra Assis].
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Millette, James R. "Reference Methods For Analyzing For Asbestos In Various Media." Microscopy Today 3, no. 10 (1995): 10–11. http://dx.doi.org/10.1017/s1551929500065640.
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Microscopy remains the primary tool for the analysis and quantification of asbestos in occupational and environmental studies. The American Society for Testing and Materials (ASTM) has recently approved two new Standard Methods for the analysis of asbestos in settled dust. Both methods require the use of a transmission electron microscope (TEM) equipped with an energy dispersive x-ray analysis system. Other methods curently in use require the use of a polarized light microscope {PLM) or phase contrast microscope (PCM).
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Neilly, J. P., J. S. Deng, J. L. House, and J. A. Fagerland. "Morphological Characterization of a Sustained-Release Drug Implant by Scanning Electron Microscopy, Polarized Light Microscopy and Image Analysis." Microscopy and Microanalysis 4, S2 (1998): 932–33. http://dx.doi.org/10.1017/s1431927600024788.
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Septacin is a sustained-release antibiotic currently under development by the Hospital Products Division of Abbott Laboratories. The product is designed to be used as an anti-infective implant in orthopedic surgical procedures with a sustained drug release for up to six weeks in vivo. It consists of gentamicin sulfate formulated with a bioerodable polyanhydride copolymer. The polymer is biodegradable and has been approved by the FDA for human clinical trials. The final product is obtained by mixing 20% gentamicin sulfate with molten polymer and injection molding it to form cylindrical Septacin beads.The microstructure of drug particles and polymer matrix is critical to the performance of sustained release products, thus scanning electron microscopy (SEM) and polarized light microscopy (PLM) were utilized in this study. SEM has proven useful for evaluating the microstructure of drug formulations3 and was used to examine the drug-polymer matrix structure. Average drug particle size and distribution were determined, and the drug-polymer boundary was evaluated.
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Polzer, Stanislav, T. Christian Gasser, Caroline Forsell, et al. "Automatic Identification and Validation of Planar Collagen Organization in the Aorta Wall with Application to Abdominal Aortic Aneurysm." Microscopy and Microanalysis 19, no. 6 (2013): 1395–404. http://dx.doi.org/10.1017/s1431927613013251.
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AbstractArterial physiology relies on a delicate three-dimensional (3D) organization of cells and extracellular matrix, which is remarkably altered by vascular diseases like abdominal aortic aneurysms (AAA). The ability to explore the micro-histology of the aorta wall is important in the study of vascular pathologies and in the development of vascular constitutive models, i.e., mathematical descriptions of biomechanical properties of the wall. The present study reports and validates a fast image processing sequence capable of quantifying collagen fiber organization from histological stains. Powering and re-normalizing the histogram of the classical fast Fourier transformation (FFT) is a key step in the proposed analysis sequence. This modification introduces a powering parameterw, which was calibrated to best fit the reference data obtained using classical FFT and polarized light microscopy (PLM) of stained histological slices of AAA wall samples. The values ofw= 3 and 7 give the best correlation (Pearson's correlation coefficient larger than 0.7,R2about 0.7) with the classical FFT approach and PLM measurements. A fast and operator independent method to identify collagen organization in the arterial wall was developed and validated. This overcomes severe limitations of currently applied methods like PLM to identify collagen organization in the arterial wall.
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Tetschke, Florian, Jonas Golde, Tobias Rosenauer, et al. "Correlation between Lesion Progression and Depolarization Assessed by Polarization-Sensitive Optical Coherence Tomography." Applied Sciences 10, no. 8 (2020): 2971. http://dx.doi.org/10.3390/app10082971.
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The detection of early stages of caries is still one of the major challenges in preservative dentistry. Since it is known from polarized light microscopy (PLM) that intrinsic enamel birefringence is affected by demineralization, polarization-sensitive optical coherence tomography (PSOCT) could facilitate the noninvasive detection and assessment of early carious lesions. The present study aims to correlate enamel lesion progression and depolarization measurements based on PSOCT in an artificial demineralization model. A total of 18 enamel slabs were prepared from bovine incisor teeth and demineralized in an acetic buffer solution for up to 49 days. The degree of polarization (DOP)—indicating depolarization and thus, demineralization—was calculated from PSOCT measurements and compared to lesion depth which was measured from PLM images. Artificial lesions showed characteristic zones of natural enamel demineralization in PLM images. DOP representations showed no depolarization for sound, nondemineralized enamel, whereas significant changes were found after 15 days of acid-exposition. The linear regression analysis of the DOP and the measured lesion depth showed a substantial correlation ( R 2 = 0.71 ). The results indicate that PSOCT-based depolarization imaging provides an unambiguous contrast for initial enamel demineralization which is correlated to the lesion progression.
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Briso, André Luiz Fraga, Rafael Simões Gonçalves, Fernanda Bernardi da Costa, Marjorie de Oliveira Gallinari, Luciano Tavares Angelo Cintra, and Paulo Henrique dos Santos. "Demineralization and Hydrogen Peroxide Penetration in Teeth with Incipient Lesions." Brazilian Dental Journal 26, no. 2 (2015): 135–40. http://dx.doi.org/10.1590/0103-6440201300225.
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The aim of this study was to evaluate the demineralization and hydrogen peroxide (HP) penetration in teeth with incipient lesions submitted to bleaching treatment. For analysis of HP penetration, sound and demineralized enamel/dentin discs were placed in artificial pulp chambers containing acetate buffer solution. After bleaching treatment, this solution was subjected for analysis of optical density by spectrophotometry and the disc surfaces were analyzed with scanning electron microscopy (SEM) and polarized light microscopy (PLM). The remaining discs were subjected for cross-sectional hardness analysis at different depths. Data were analyzed by repeated measures ANOVA and PLSD Fisher test (a=0.05). It was observed that previously demineralized teeth showed greater HP penetration (p<0.05). The bleaching treatment caused changes to a depth of 20 µm in sound enamel and up to 90 µm in demineralized enamel. SEM and PLM images revealed that the bleaching treatment caused superficial changes that were considerably more accentuated in previously demineralized teeth. It may be concluded that the enamel mineralization level influences HP penetration and the bleaching agent contributed to increase the demineralization depth.
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Retamoso, Luciana Borges, Francisco Montagner, Elisa Souza Camargo, Roberto Willer Farinazzo Vitral, and Orlando Motohiro Tanaka. "Polarized Light Microscopic Analysis of Bone Formation After Inhibition of Cyclooxygenase 1 and 2." Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology 293, no. 2 (2009): 195–99. http://dx.doi.org/10.1002/ar.21035.
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Bernegossi, Jéssica, Carla Raquel Fontana, Karina Sampaio Caiaffa, Cristiane Duque, and Marlus Chorilli. "Inhibitory Effect of a KSL-W Peptide-Loaded Poloxamer 407-Based Microemulsions for Buccal Delivery on Fusobacterium nucleatum Biofilm." Journal of Biomedical Nanotechnology 16, no. 3 (2020): 390–97. http://dx.doi.org/10.1166/jbn.2020.2896.
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KSL-W peptide has demonstrated antibacterial and antifungal activity and inhibitory effects against oral biofilm. This study aimed to check out the effect of chlorhexidine (CLX) or KSL-W peptide-loaded poloxamer 407-based microemulsions for buccal delivery on Fusobacterium nucleatum (F. nucleatum) biofilm. The formulation (F) containing 10% copolymer poloxamer 407 dispersion (1%), 40% oleic acid and 50% PPG-5-CETETH-20 was characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheology, bioadhesive and syringeability; and in the treatment of a biofilm produced by F. nucleatum. The darkfield images obtained by PLM and the SAXS curves with an extended peak indicated that the system was characteristic of microemulsions. In a continuous analysis, microemulsions exhibited Newtonian behavior. In frequency, the oscillatory analysis profile presented predominantly viscous behavior. Bioadhesive force detected in the analysis of F (7.4 ± 1.81 mN˙ s) and syringeability (17.83± 5.97 N · mm) being adequate values for buccal administration. After 4 h, KSL-W-loaded F shown over 20% higher effectiveness than chlorhexidine-loaded microemulsions. In conclusion, the KSL-W-loaded microemulsions showed a considerable reduction in F. nucleatum biofilm formation and presented promising structural properties for buccal drug delivery.
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Ewing, D. J., Qamar-ul Wahab, Sergey P. Tumakha, et al. "A Study of Inhomogeneous Schottky Diodes on n-Type 4H-SiC." Materials Science Forum 527-529 (October 2006): 911–14. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.911.
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In this study, we performed a statistical analysis of 500 Ni Schottky diodes distributed across a 2-inch, n-type 4H-SiC wafer with an epilayer grown by chemical vapor deposition. A majority of the diodes displayed ideal thermionic emission when under forward bias, whereas some diodes showed ‘double-barrier’ characteristics with a ‘knee’ in the low-voltage log I vs. V plot. X-ray topography (XRT) and polarized light microscopy (PLM) revealed no correlations between screw dislocations and micropipes and the presence of double-barrier diodes. Depth resolved cathodoluminescence (DRCLS) indicated that certain deep-level states are associated with the observed electrical variations.
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Sabatini, R. L., Toshi Sugama, and Leonidas Petrakis. "Analysis of IN-SITU Converted Chrysotile Asbestos Fibers in Sprayed on Fireproofing." Microscopy and Microanalysis 4, S2 (1998): 480–81. http://dx.doi.org/10.1017/s1431927600022522.
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A BNL-Grace process has been developed to chemically convert in-situ, the chrysotile fibers of sprayed-on fireproofing products to an unregulated glassy material. The effectiveness of this process has been convincingly demonstrated using Analytical Electron Microscopy and X-Ray Diffraction techniques.Asbestos minerals were used in fireproofing materials because of their excellent physical properties including fire resistance, high tensile strength, heat and electrical insulation, and resistance to acids and alkali. But in 1975 the Environmental Protection Agency began regulating materials containing > 1% asbestos.The new in-situ BNL-Grace process, which uses a foamy solution sprayed directly onto asbestos-containing fireproofing chemically digests essentially all the asbestos fibers, transforming them into harmless materials. After treatment, the fireproofing is no longer a regulated material. The process produces essentially no waste.Our problem was to demonstrate that all of the asbestos was converted and that the remaining materials were no longer regulated. Typical analysis methods use conventional optical and Polarized Light Microscopy (PLM) to measure and observe fibers.
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Oliveira, Marcela B., Alice Haddad do Prado, Jéssica Bernegossi, et al. "Topical Application of Retinyl Palmitate-Loaded Nanotechnology-Based Drug Delivery Systems for the Treatment of Skin Aging." BioMed Research International 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/632570.
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The objective of this study was to perform a structural characterization and evaluate thein vitrosafety profile andin vitroantioxidant activity of liquid crystalline systems (LCS) with and without retinyl palmitate (RP). LCS containing polyether functional siloxane (PFS) as a surfactant, silicon glycol copolymer (SGC) as oil phase, and water in the ratios 30 : 25 : 45 and 40 : 50 : 10 with (OLSv= RP-loaded opaque liquid system andTLSv= RP-loaded transparent liquid system, respectively) and without (OLS and TLS, respectively) RP were studied. Samples were characterized using polarized light microscopy (PLM) and rheology analysis.In vitrosafety profile was evaluated using red cell hemolysis andin vitrocytotoxicity assays.In vitroantioxidant activity was performed by the DPPH method. PLM analysis showed the presence of lamellar LCS just to TLS. Regardless of the presence of RP, the rheological studies showed the pseudoplastic behavior of the formulations. The results showed that the incorporation of RP in LCS improved the safety profile of the drug.In vitroantioxidant activity suggests that LCS presented a higher capacity to maintain the antioxidant activity of RP. PFS-based systems may be a promising platform for RP topical application for the treatment of skin aging.
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Millette, James R. "Recent Activities in Environmental Microscopy." Microscopy Today 1, no. 8 (1993): 4. http://dx.doi.org/10.1017/s1551929500069030.
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The microscope has always played an important part in the field of environmental science. Initially it was involved mostly with those who analyzed for biological indicators of pollution or those who examined air pollution particles, but more recently it is being used by a large number of analysts of particulate samples following the concern over asbestos in schools. With the Asbestos Hazard Emergency Response Act (AHERA) of 1987, transmission electron microscopy (TEM) formally joined polarized light microscopy (PLM) and phase contrast microscopy (PCM) as a recognized regulation-required standard procedure for the analysis of asbestos. While asbestos remains a considerable activity in environmental microscopy, other areas including analysis of nan-asbestos fibers such as ceramic fibers, lead particle source determination, respirable silica measurement, and indoor air qualify particle examination have seen some interesting developments.
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Masuda, Allan Kenji, Mayra Fidelis Zamboni Quitero, Luciana Cardoso Espejo-Trung, and Maria Aparecida Alves Cerqueira Luz. "Histological and microhardness evaluation of early artificial carious lesions in human and bovine enamel: in vitro study." Brazilian Dental Science 16, no. 4 (2013): 49. http://dx.doi.org/10.14295/bds.2013.v16i4.929.
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<p><strong>Objective: </strong>Early carious lesions in bovine and humanenamel developed in vitro using a pH cycling regimenwere compared. <strong>Material and Methods: </strong>Fifteencentral bovine incisors and fifteen recently extractedhuman third molars were randomly divided into twogroups: ten for the cross-sectional microhardness test(MT) and five for polarized light microscopy (PLM)analysis. Enamel blocks measuring 5 x 5 mm weremade from the buccal face of the teeth. The blocksused for the MT were sliced into two halves: “A” and“B”. “A” slices were embedded in acrylic resin, withthe face of the dentin-enamel junction left exposedfor the MT prior to pH cycling. “B” slices and wholeblocks were coated with acid-resistant varnish,except a 3 x 3 mm central window, and submitted tothe pH cycling regimen (demineralizing solution for3 h and remineralizing solution for 21 h) over fiveconsecutive days. The “B” slices were then submittedto the MT and the whole blocks were processed forthe PLM study. <strong>Results: </strong>The PLM analysis revealedshallow, extensive lesions in the bovine enamel,hardly showing the superficial, dark and translucentzones, as well as deep cavity lesions in the humanenamel, with the body of the lesion and the darkzone evident. The MT revealed a significant decreasein microhardness in the superficial levels of thebovine enamel caries and at all depth levels of thehuman enamel caries. <strong>Conclusion: </strong>The pH cyclingregimen adopted led to the development of deeperand more demineralized carious lesions in humanenamel than bovine enamel</p><p>Keywords<br />Dental caries; Dental enamel; Microhardness tests; Polarization microscopy.</p>
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Chu, Xiao-qin, Yong Zhang, Jie Huang, et al. "The Effect of Prescription on the Framework of Lipid Matrix and In Vitro Properties." Current Drug Delivery 16, no. 8 (2019): 737–50. http://dx.doi.org/10.2174/1567201816666190620115403.
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Purpose: To clarify the inner framework and relative properties in vitro of Lyotropic liquid crystal (LLC) based on various prescriptions by using hydrophilic sinomenine hydrochloride (SH) and lipophilic cinnamaldehyde (CA) as model drugs. Methods: Phase structures were checked by polarized light microscopy (PLM) and small-angle X-ray scattering (SAXS). Rheological studies and Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) analysis were carried out to reveal their molecular interactions. In vitro release and skin permeation were conducted by Franz diffusion cell. Results: PLM and SAXS showed double diamond cubic crystal. All the samples displayed characteristics of non-Newtonian fluid, and the molecular interactions increased with the reducing water. ATRFTIR showed that the strongest strength of hydrogen bond emerged in the formulation with 32% water. Released SH of S2 and S3 arrived over 80%, while S1 only reached 45%, and that of CA was about 23%. Water-rich prescription gave higher percutaneous penetration for hydrophilic drugs, whereas no significant difference existed in CA permeation. Conclusion: Proportion of Phytantriol to water determined the LLC assembling and affected the dissolving status of hydrophilic substance, thereby impacting on the location sites of guest molecular interactions among the substances, rheology properties, and finally the release and penetration behavior in vitro. Adjusting the basic prescription was the key to obtain satisfactory percutaneous delivery and stability for LLC carrying multi-therapeutic agents.
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Gonçalves, Rafael Simões, Polliana Mendes Candia Scaffa, Marina Ciccone Giacomini, Cristina de Mattos Pimenta Vidal, Heitor Marques Honório, and Linda Wang. "Sodium Trimetaphosphate as a Novel Strategy for Matrix Metalloproteinase Inhibition and Dentin Remineralization." Caries Research 52, no. 3 (2018): 189–98. http://dx.doi.org/10.1159/000484486.
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The effect of sodium trimetaphosphate (STMP) as an antiproteolytic and remineralizing agent on demineralized dentin was evaluated in vitro. The inhibitory potential of STMP at 0.5, 1.5, 3.5, and 5% against recombinant matrix metalloproteinases (MMPs) MMPs-2 and -9 was assessed by zymography. To investigate its remineralization potential, 40 bovine root specimens were obtained and subjected to a demineralization protocol to produce caries-like dentin lesions. After that, dentin surfaces were divided into 3 areas: (1) mineralized (no treatment); (2) demineralized; and (3) demineralized/treated with STMP and submitted to a pH-cycling associated or not with STMP (1.5, 3.5, or 5% STMP, 10 min of treatment). After that, superficial hardness (SH) and cross-sectional hardness (CSH) were determined. Polarized light microscopy (PLM) was used to qualitatively evaluate mineralization within the caries-like lesions. The zymographic analysis showed that STMP solution is a potent inhibitor of the gelatinolytic activity of MMPs-2 and -9 depending on the dose, since the lowest concentration (0.5%) partially inhibited the enzyme activity, while the higher concentrations completely inhibited enzyme activity. Regarding remineralization effect, only 1.5% STMP solution enhanced both the SH and CSH. PLM showed that the area treated with 1.5% STMP presented similar birefringence as mineralized sound dentin. In conclusion, 1.5% STMP solution is effective as an antiproteolytic agent against MMPs and promotes dentin remineralization.
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Chow, Clara Ka Wai, Christine D. Wu, and Carla A. Evans. "In VitroProperties of Orthodontic Adhesives with Fluoride or Amorphous Calcium Phosphate." International Journal of Dentistry 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/583521.
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Thisin vitrostudy evaluated the efficacy of orthodontic adhesives with fluoride or amorphous calcium phosphate (ACP) in reducing bacterial adhesion and enamel demineralization. Forty human premolars each sectioned buccolingually into three parts were bracketed with control resin (Transbond XT) or adhesives containing ACP (Aegis Ortho) or fluoride (QuickCure). Artificial lesions induced by pH cycling were examined by X-ray photoelectron spectrophotometry (XPS) and polarized light microscopy (PLM). After 28 days, Aegis Ortho demonstrated the lowest calcium and phosphorous content by XPS analysis. After 42 days, reductions in lesion depth areas were 23.6% for Quick Cure and 20.3% for Aegis Ortho (P<0.05). In the presence of 1% sucrose, adhesion ofStreptococcus mutansto Aegis Ortho and Quick Cure was reduced by 41.8% and 37.7% (P<0.05) as compared to Transbond XT. Composites containing ACP or fluoride reduced bacterial adherence and lesion formation as compared to a composite without ACP or fluoride.
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Freire, Maria Teresa, António Santos Silva, Maria do Rosário Veiga, Jorge de Brito, and Frank Schlütter. "Natural or Artificial? Multi-Analytical Study of a Scagliola from Estoi Palace Simulating Imperial Red Porphyry." Microscopy and Microanalysis 22, no. 6 (2016): 1281–303. http://dx.doi.org/10.1017/s1431927616011909.
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AbstractIn this paper the characterization of a gypsum plaster sample from the end of the 19th century simulating imperial red porphyry using a multi-analytical approach is presented and discussed. The results of X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TGA-DTA), physical and mechanical properties are summarized. In order to have further insight into the microstructure, polarized light microscopy (PLM), scanning electron microscopy coupled with energy dispersive X-ray spectrometer (SEM-EDS), and micro Raman spectroscopy analyzes were also made. They helped to clarify the main issues raised by the other complementary analytical techniques and allowed the establishment of interrelations between the different properties, providing important information about the materials, the skills, and the technological development involved in the art of imitating noble stones with gypsum pastes. This study also contributes to our knowledge concerning the preservation of these types of elements that are important in the context of European decorative arts and rarely reported in the literature.
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Pauli, Chantal, Won C. Bae, Michael Lee, et al. "Ultrashort–Echo Time MR Imaging of the Patella with Bicomponent Analysis: Correlation with Histopathologic and Polarized Light Microscopic Findings." Radiology 264, no. 2 (2012): 484–93. http://dx.doi.org/10.1148/radiol.12111883.
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Longoria-Rodríguez, Francisco E., Lucy T. González, Yasmany Mancilla, et al. "Sequential SEM-EDS, PLM, and MRS Microanalysis of Individual Atmospheric Particles: A Useful Tool for Assigning Emission Sources." Toxics 9, no. 2 (2021): 37. http://dx.doi.org/10.3390/toxics9020037.
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In this work, the particulate matter (PM) from three different monitoring stations in the Monterrey Metropolitan Area in Mexico were investigated for their compositional, morphological, and optical properties. The main aim of the research was to decipher the different sources of the particles. The methodology involved the ex situ sequential analysis of individual particles by three analytical techniques: scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), polarized light microscopy (PLM), and micro-Raman spectroscopy (MRS). The microanalysis was performed on samples of total suspended particles. Different morphologies were observed for particles rich in the same element, including prismatic, spherical, spheroidal, and irregular morphologies. The sequential microanalysis by SEM-EDS/PLM/MRS revealed that Fe-rich particles with spherical and irregular morphologies were derived from anthopogenic sources, such as emissions from the metallurgical industry and the wear of automobile parts, respectively. In contrast, Fe-rich particles with prismatic morphologies were associated with natural sources. In relation to carbon (C), the methodology was able to distinguish between the C-rich particles that came from different anthopogenic sources—such as the burning of fossil fuels, biomass, or charcoal—and the metallurgical industry. The optical properties of the Si-rich particles depended, to a greater extent, on their chemical composition than on their morphology, which made it possible to quickly and accurately differentiate aluminosilicates from quartz. The methodology demonstrated in this study was useful for performing the speciation of the particles rich in different elements. This differentiation helped to assign their possible emission sources.
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Bély, M. "Histochemical Differential Diagnosis and Polarization Optical Analysis of Amyloid and Amyloidosis." Scientific World JOURNAL 6 (2006): 154–68. http://dx.doi.org/10.1100/tsw.2006.35.
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Amyloidosis is characterized by extracellular deposition of protein fibrils of chemically heterogeneous composition. Early recognition and identification of amyloid deposits allows an early start of therapy, which may entail a better prognosis. Congo red staining according to Romhányi (1971) is a highly specific and sensitive method for early microscopic recognition of amyloidosis. The main and most important types of amyloidosis may be distinguished by classic histochemical methods of performate pretreatment according to Romhányi (1979), or by KMnO4oxidation according to Wright (1977) followed by Congo red staining and viewed under polarized light. Differences in the speed of breakdown (disintegration) of amyloid deposits according to Bély and Apáthy allow a more precise distinction of various types of amyloid.
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Brumit, M. C., B. O. Buschmann, C. W. Boudreaux, F. McDonald, and J. A. C. King. "SEM Analysis of Urine Crystals Prepared with Cytorich Red." Microscopy and Microanalysis 6, S2 (2000): 476–77. http://dx.doi.org/10.1017/s1431927600034875.
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Microscopic evaluation of urine sediment by the cytology laboratory can provide valuable information to the clinician. While some crystal types are considered normal, others are abnormal and indicate disease. Traditional analysis within the cytology laboratory includes direct cytospin preparations and smears of the urine sample. Light microscopy with polarized light is then utilized to examine the slide preparations.Many cytology laboratories have recently incorporated liquid-based technology for gynecologic and non-gynecologic specimen preparation. Specimens placed in the proprietary fluid are processed according to the manufacturer's directions with the ultimate result of a thin, circular layer of cells on the slide. The advantages of liquidbased methods include concentration of the cells into a thin layer, localization to a small area of the slide, minimization of background debris, and ability to make additional specimens from the same sample. When the liquid-based slide preparations of urine made in our lab were compared to the conventional cytospin smears,
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Lv, Kui Long, Hai Wen Yuan, Xiang Cai Meng, and Xing Yi Li. "Remineralized Evaluation of Nano- Hydroxyapatite to Artificial Caries." Advanced Materials Research 105-106 (April 2010): 576–79. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.576.
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The aim of this study is to describe the remineralization effect of the nano-HA on artificial caries. The artificial dental caries are made by using sour solution, and constructing an artificial mouth' plaque culture system in vitro respectively. The scanning electron microscope (SEM) and the optical microscope are used to observe the surface of enamel specimens. The effect of remineralization is assessed with the polarized light microscopy (PLM) and the confocal laser scanning microscope (CLSM) by measuring three lesion parameters (area, total and average fluorescence). The SEM analysis shows that the cavities and defects of enamel surface are decreased and many mineral salts are sedimentated, which indicate that the nano-HA could promote remineralization for the demineralized enamel. The inhibitory effect of the spherical nano-HA on dental caries is detected in the artificial mouth test. The CLSM shows that demineralization of enamel is reduced by adding the spherical nano-HA in artificial mouth. The results show that the spherical nano HA have a remineralization effect on the artificial dental caries dramatically, and can prevent and decrease caries.
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Carvalho, Fernanda, Andreia Lopes, Antonella Curulli, et al. "The Case Study of the Medieval Town Walls of Gubbio in Italy: First Results on the Characterization of Mortars and Binders." Heritage 1, no. 2 (2018): 468–78. http://dx.doi.org/10.3390/heritage1020031.
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Good conservation and restoration practices of cultural heritage assets rely on the knowledge of original materials. In the framework of the HERACLES Project (HERACLES—HEritage Resilience Against CLimate Events on Site, H2020 Grant Agreement 700395), dealing with the effects of climatic actions and natural hazards on built heritage, a set of important heritage sites are currently under study to improve their resilience against climate events. Among these are the medieval Gubbio Town Walls in Italy. The present work focuses on the mortars and binders of this monument and collected samples related to different parts of the Walls, corresponding to various historical periods of construction and interventions. They were characterized to determine their minerochemical composition, thermal behavior, and morphology. For that purpose, ex-situ laboratory techniques, such as X-ray diffraction (XRD), wavelength dispersive X-ray fluorescence (WDXRF), optical microscopy (OM), polarized light microscopy (PLM), scanning electron microscopy (SEM), and simultaneous differential thermal analysis and thermogravimetry (TG-DTA) were used to discern trends in different sampling areas due to construction/reconstruction periods and building techniques.
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Milak, Spomenka, Angela Chemelli, Otto Glatter, and Andreas Zimmer. "Vancomycin Loaded Glycerol Monooleate Liquid Crystalline Phases Modified with Surfactants." Pharmaceutics 12, no. 6 (2020): 521. http://dx.doi.org/10.3390/pharmaceutics12060521.
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The influence of two tuning agents, polyglycerol ester (PE) and triblock copolymer (TC), on the properties of glycerol monooleate (MO) liquid crystalline phase (LCP) was investigated to achieve the therapeutic concentration of vancomycin hydrochloride (VHCl) into the eye, topically during 60 min (1 h) and intravitreally during 2880 min (48 h). Different techniques were used to elucidate the impact of surfactants on the structure of the LCP: polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), and in vitro release tests I and II (simulating local and intravitreal application in the eye). The structure analysis by SAXS depicts that the inclusion of PE into the MO LCP provided partial transition of a hexagonal phase into a lamellar phase, and TC induced a partial transition of a hexagonal phase into an LCP which identification was difficult. The LCP modulated with PE and TC demonstrated different VHCl’s release patterns and were evaluated by comparing our release data with the literature data. The comparison indicated that the LCP modulated with 30% w/w PE could be a promising VHCl delivery system intravitreally during 2880 min.
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Singh, A. P., and M. E. Hedley. "Electron microscopic and chemical study of degraded Pinus radiata wood from a marine pile." Canadian Journal of Botany 69, no. 12 (1991): 2762–71. http://dx.doi.org/10.1139/b91-347.
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During an inspection of marine piles, 12 years after installation, severe degradation was noted on one of them in the vicinity of a corroded eyebolt. The wood was dark brown in colour and tended to crumble easily. Wood fragments were examined by light microscopy and scanning and transmission electron microscopy and were also analyzed for carbohydrates and lignin. Light microscopy indicated numerous cracks in tracheid walls resulting in delamination at the middle lamella – S1 and S1–S2 boundaries and also in fractures across the tracheid wall. Chemical analysis showed extensive loss of both hemicellulose and cellulose. Observations with polarized light microscopy supported the data from chemical analysis on cellulose degradation, indicating a loss of crystallinity. Although presence of microbial flora in the lumen of wood cells was revealed by scanning electron microscopy, transmission electron microscopy showed only occasional soft rot decay zones in the S2 layer. The degradation of Pinus radiata wood from this sample appears to have been caused primarily by brown rot attack and (or) iron corrosion products, soft rot attack playing a minor role. Key words: Pinus radiata wood, marine pile, wood cell wall degradation, electron microscopy.
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Baker, K. W., L. King, R. Walker, I. Piscopo, and A. Smith. "A Simple Correlative Technique for Morphologic and Energy-Dispersive Analysis of Glass-Mounted Paraffin Sections." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 308–9. http://dx.doi.org/10.1017/s0424820100164003.
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Tissue sections, smears, and many other varied types of specimen are often mounted on glass slides for light microscopic (LM) evaluation and analysis. These same preparations’ using gold/palladiumcoated glass slides as specimen mounts, are also well suited to correlative scanning electron microscopy (SEM) and, energy dispersive X-ray analysis (SEM/EDX). The following short note describes a procedure for glass-mounted specimens that provides slides suitable for combined LM, SEM and SEM/EDX characterization. In addition, the method establishes a specimen-based reference point for the empirical determination of optimum electron probe depth and accelerating voltage for SEM/EDX analysis.For illustrative purposes we used sections of mammalian kidney cortex known to be heavily laden with crystalline deposits of unknown structure and composition.In each sample, birefringent crystalline material was initially observed in hematoxylin and eosinstained paraffin sections using bright field polarized light microscopy (Fig. 1).
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Crăciun, Antarinia, Ioana Bȃldea, Ana Ispas, et al. "Evaluation of Surface Characteristics and Cytotoxicity of Dental Composites." Coatings 10, no. 8 (2020): 749. http://dx.doi.org/10.3390/coatings10080749.
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The purpose of this study was to evaluate the surface and in vitro cytotoxicity on human dysplastic oral keratinocytes (DOK) of four commercial resins-based dental composites commonly used in prosthodontics dental therapies: two indirect composites for crown and bridges—SR Adoro (IvoclarVivadent GmbH) and Solidex (Shofu Dental GmbH); and two dual-curing luting resin cements—RelyxUnicem (3M ESPE Dental Products) and Variolink Esthetic DC (IvoclarVivadentGmbH). A complex assessment of surface characteristics of the four materials was conducted before and after the exposure to artificial saliva through various analyses, such as Scanning Electron Microscopy, Atomic Force Microscopy and Cross Polarized Light Microscopy (PLM). The results showed that DOK viability was not severely affected by exposure to any of these materials; however, Variolink expressed higher values but still above the toxicity level of the rest of the composites. The analysis of the surface structure between initial and artificial saliva exposed specimens returned a compact aspect in both categories and although Variolink and Relyx were subjected to increased roughness after saliva exposure, no damage of the internal compactness was recorded, demonstrating a fair behavior of the luting cements in contact with the saliva.
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Ahn, H., J. Hong, D. Kim, I. Rhyu, and Y. Kye. "217 The effect of dermal microscopic parameters on the optical skin properties: the analysis using crossed polarized light imaging on fresh cadavers." Journal of Investigative Dermatology 139, no. 9 (2019): S251. http://dx.doi.org/10.1016/j.jid.2019.07.218.
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Madrid, Cristhian C., Mariana de Pauli Paglioni, Sergio R. Line, et al. "Structural Analysis of Enamel in Teeth from Head-and-Neck Cancer Patients Who Underwent Radiotherapy." Caries Research 51, no. 2 (2017): 119–28. http://dx.doi.org/10.1159/000452866.
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Objective: To analyze macroscopic, microscopic, and ultrastructural aspects of enamel from head-and-neck cancer patients submitted to radiotherapy. Materials and Methods: Twenty sound extracted permanent molars were used and divided into 2 groups. The experimental group consisted of 10 molars from head-and-neck cancer patients submitted to radiotherapy with total doses that ranged from 50 to 70 Gy. Ten molars from patients who did not receive radiotherapy were matched with experimental-group samples by anatomic tooth group and comprised the control group. To perform a macroscopic analysis, standardized photos of different enamel faces were taken with a camera. Teeth were subjected to longitudinal cuts and hand polished to a final thickness of 0.1 mm. Enamel was analyzed under polarized light microscopy, and optical retardation values of birefringence were calculated in cervical, cusp, and occlusal pit areas. Subsequently, the same enamel areas were analyzed by scanning electron microscopy. Data from optical retardation values were statistically analyzed by 2-way ANOVA and Fisher's test (α < 0.05). Results: No macroscopic differences were observed between the irradiated and control groups. Polarized light microscopy analysis revealed that cervical enamel exhibited darker areas characterized by discrete birefringence patterns compared to the control enamel. Optical retardation values were only significantly different in the cervical enamel of the irradiated and control groups (p < 0.0001). Scanning electron microscopy analysis revealed more evident interprismatic spaces in the cervical and outer cusp enamel of irradiated samples. Conclusions: Head-and-neck radiotherapy reduced optical retardation values of birefringence in cervical enamel, and the interprismatic spaces became more evident.
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Chimello, Daniela T., Mônica C. Serra, Antonio L. Rodrigues, Jesus D. Pécora, and Silmara A. M. Corona. "Influence of cavity preparation with Er:YAG Laser on enamel adjacent to restorations submitted to cariogenic challenge in situ: A polarized light microscopic analysis." Lasers in Surgery and Medicine 40, no. 9 (2008): 634–43. http://dx.doi.org/10.1002/lsm.20684.
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Beaufort, Luc, Yves Gally, Baptiste Suchéras-Marx, Patrick Ferrand, and Julien Duboisset. "Technical note: A universal method for measuring the thickness of microscopic calcite crystals, based on bidirectional circular polarization." Biogeosciences 18, no. 3 (2021): 775–85. http://dx.doi.org/10.5194/bg-18-775-2021.
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Abstract. Coccoliths are major contributors to the particulate inorganic carbon in the ocean that is a key part of the carbon cycle. The coccoliths are a few micrometres in length and weigh a few picogrammes. Their birefringence characteristics in polarized optical microscopy have been used to estimate their mass. This method is rapid and precise because camera sensors produce excellent measurements of light. However, the current method is limited because it requires a precise and replicable set-up and calibration of the light in the optical equipment. More precisely, the light intensity, the diaphragm opening, the position of the condenser and the exposure time of the camera have to be strictly identical during the calibration and the analysis of calcite crystal. Here we present a new method that is universal in the sense that the thickness estimations are independent from a calibration but result from a simple equation. It can be used with different cameras and microscope brands. Moreover, the light intensity used in the microscope does not have to be strictly and precisely controlled. This method permits the measurement of crystal thickness up to 1.7 µm. It is based on the use of one left circular polarizer and one right circular polarizer with a monochromatic light source using the following equation: d=λπΔnarctanILRILL, where d is the thickness, λ the wavelength of the light used, Δn the birefringence, and ILR and ILL the light intensity measured with a right and a left circular polarizer. Because of the alternative and rotational motion of the quarter-wave plate of the circular polarizer, we coined the name of this method “bidirectional circular polarization” (BCP).
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Blobel, Swen, Karin Thielsch, Markus Kaestner, and Volker Ulbricht. "Application of Real-Time Photoelastic Analysis to Single Fibre Fragmentation Tests." Applied Mechanics and Materials 24-25 (June 2010): 239–44. http://dx.doi.org/10.4028/www.scientific.net/amm.24-25.239.
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One of our main research areas is the trans-scale modelling of damage in composite materials, which consist of a polymer matrix and carbon or glass fibres in different material combinations and geometrical arrangements. From the local stress redistribution in the fibre-matrix interphase and in the surrounding matrix material information on the parameters of microscopic damage models for composite materials can be obtained. Owing to the difficult interface characterisation based on the properties of the single material components, a photoelastic analysis of single fibre fragmentation tests is performed. In addition to the qualitative visual interpretation in polarized light, an enhanced quantitative analysis in combination with digital photoelasticity using a four image phase shifting method will be applied [1]. As the sequential capturing of images might cause incorrect results, these four pictures are grabbed simultaneously. This allows for continuous testing. Additionally, errors due to the relaxation behaviour of the matrix material can be avoided. To this, a modular optical system consisting of a variable long distance microscope and a beam dividing module proposed by [2] was developed. It allows for the simultaneous projection of four different filtered images of one microscopic scene to the four quadrants of a CCD chip. This special equipment gives the possibility to apply quantitative photoelasticity to tensile tests performed on standard testing machines. This paper explains the measurement hardware and discusses the main problems and realised solutions from picture capturing through image processing to real-time photoelastic analysis at the present state of development. Exemplary results for the qualitative analysis of selected material combinations and different manufacturing processes are shown.
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Tarani, Evangelia, Klementina Pušnik Črešnar, Lidija Fras Zemljič, et al. "Cold Crystallization Kinetics and Thermal Degradation of PLA Composites with Metal Oxide Nanofillers." Applied Sciences 11, no. 7 (2021): 3004. http://dx.doi.org/10.3390/app11073004.
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Poly(lactic acid) (PLA) nanocomposites with antimicrobial fillers have been increasingly explored as food packaging materials that are made of a biobased matrix and can minimize food loss due to spoilage. Some of the most commonly studied fillers are zinc oxide (ZnO), titanium dioxide (TiO2), and silver nanoparticles (AgNPs). In this work, nanocomposites with 1 wt.% of each filler were prepared by melt mixing. An extensive study of thermally stimulated processes such as crystallization, nucleation, degradation, and their kinetics was carried out using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). In detail, non-isothermal cold crystallization studies were performed with DSC and polarized light microscopy (PLM), and kinetics were analyzed with multiple equations. The activation energy of the non-isothermal cold crystallization was calculated with the methods of Kissinger and Friedman. The latter was used to also determine the Hoffman–Lauritzen parameters (Kg and U*) by applying the Vyazovkin method. Additionally, effective activation energy and kinetic parameters of the thermal decomposition process were determined by applying the isoconversional differential method and multivariate non-linear regression method. According to TGA results, metal oxide nanofillers affected the thermal stability of PLA and caused a decrease in the activation energy values. Moreover, the fillers acted as heterogenous nucleating agents, accelerating the non-isothermal crystallization of PLA, thus reducing its activation energy. It can be concluded that metal oxide nanofillers catalytically affect the thermal degradation and crystallization of PLA samples.
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Scatigno, Claudia, Maria Preite Martinez, Nagore Prieto-Taboada, Juan Manual Madariaga, and Aida Maria Conte. "Petrographic-Mineralogical Characterization of Archaeological Materials from “Casa di Diana” Mithraeum Sited in the Open Museum of Ostia Antica." Crystals 11, no. 7 (2021): 839. http://dx.doi.org/10.3390/cryst11070839.
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Mithraea, religious Roman buildings, are very common in Italian archeological sites. There are sixteen in Ostia Antica (Rome, Italy)The poor state of conservation, due to the intrinsic environmental conditions, characterized them: they consist of open-air museums and caves simultaneously. These places of worship are characterized by the presence of heterogeneous materials, such as wall building materials (bricks and mortars) and others used for furnishings and fittings. This increases the risk of accelerated damage because the materials ‘rheology is different. Here, a full petrographic-mineralogical characterization with polarized light microscopy (PLM), X-ray diffraction (XRD), scanning electron microscope with energy dispersive X-ray (SEM-EDS) and isotopic analysis (δ13C, δ18O) is carried out on materials like travertine, marble, pumice, ceramic, and wall-building materials in “Casa di Diana” Mithraeum (Ostia Antica). Their characterization gives provenance information as well as conservation and restoration purposes. The prevalence of siliciclastic or carbonate components discriminates between red and yellow bricks, as well as different textures and minerals in the aggregate of the red ones. The mortars are typically pozzolanic, and the aggregate is mostly made up of black and red pozzolanic clasts. In the altar, apse, and aedicule, which constitute the principal place of the Mithraeum, a variety of materials used for the ornamental purpose are represented by pumices, travertine, marble, and limestone. The altar material, catalogued as marble, resulted in being a limestone coated with a white pigment.
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Ali, Mona, Hanaa Shawki, and Hussein Marey Mahmoud. "Material characterization and restoration of mural paintings of El-Muzzawaka Tombs, Dakhla Oases, Egypt." Ge-conservacion 18, no. 1 (2020): 92–107. http://dx.doi.org/10.37558/gec.v18i1.773.
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The present study demonstrates scientific procedures applied to study mural paintings in two Graeco-Roman tombs of El-Muzzawaka, Dakhla Oases, Egypt. First, a series of analytical methods was applied to determine the chemical and mineralogical composition of pigment and plaster samples collected from the studied tombs. The analyses were performed by means of digitalized optical microscopy (OM), polarized light microscopy (PLM), scanning electron microscopy attached with X-ray microanalysis detector (SEM−EDS), X−ray diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FT−IR). Analyses of the pigment samples revealed Egyptian blue, Egyptian green, green earth, black magnetite, and red/yellow ochres. The paintings were applied on a coarse plaster layer made of gypsum, anhydrite, calcite, and quartz. The preparation layer was made of two phases of calcium sulphate (gypsum and anhydrite). Further, the detection of an organic binder, of gum Arabic, confirms the application of tempera technique. The results showed that the bed rock samples contain variable amounts of quartz, anhydrite, montmorillonite, kaolinite, gypsum, and sodium chloride (halite). In situ observations showed several deterioration forms on the studied mural paintings. The destructive climatic condition of the region and the defects of the rock structure have contributed seriously in the deterioration process. Based on experimental tests, multi restoration procedures were applied in form of cleaning, reattaching paint flakes, applying injection grouts to detached layers, reconstruction of missing parts in the plaster, repair of wide-open cracks, and final protective consolidation of the painted surfaces. Further, recommendations to minimize any future damage were discussed.
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Tariq, Muhammad, Thomas Thurn-Albrecht, and Oleksandr Dolynchuk. "Heterogeneous Crystal Nucleation from the Melt in Polyethylene Oxide Droplets on Graphite: Kinetics and Microscopic Structure." Crystals 11, no. 8 (2021): 924. http://dx.doi.org/10.3390/cryst11080924.
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It is well known that the crystallization of liquids often initiates at interfaces to foreign solid surfaces. In this study, using polarized light optical microscopy, atomic force microscopy (AFM), and wide-angle X-ray scattering (WAXS), we investigate the effect of substrate–material interactions on nucleation in an ensemble of polyethylene oxide (PEO) droplets on graphite and on amorphous polystyrene (PS). The optical microscopy measurements during cooling with a constant rate explicitly evidenced that the graphite substrate enhances the nucleation kinetics, as crystallization occurred at approximately an 11 °C higher temperature than on PS due to changes in the interactions at the solid interface. This observation allowed us to conclude that graphite induces heterogeneous nucleation in PEO. By employing the classical nucleation theory for analysis of the data with reference to the amorphous PS substrate, the obtained results indicated that the crystal nuclei with contact angles in the range of 100–117° were formed at the graphite interface. Furthermore, we show that heterogeneous nucleation led to a preferred orientation of PEO crystals on graphite, whereas PEO crystals on PS had isotropic orientation. The difference in crystal orientations on the two substrates was also confirmed with AFM, which showed only edge-on lamellae in PEO droplets on graphite compared to unoriented lamellae on PS.
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Acharya, Sanjit, Yang Hu, and Noureddine Abidi. "Cellulose Dissolution in Ionic Liquid under Mild Conditions: Effect of Hydrolysis and Temperature." Fibers 9, no. 1 (2021): 5. http://dx.doi.org/10.3390/fib9010005.
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This study investigated the effect of acid hydrolysis of cellulose on its dissolution under mild conditions in ionic liquid, 1-butyl-3-methylimidazolium acetate/N,N-dimethylacetamide (BMIMAc/DMAc). Acid hydrolysis of high molecular weight (MW) cotton cellulose (DP > 4000) was carried out to produce hydrolyzed cotton (HC) samples for dissolution. The HC samples were characterized using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), and the dissolution process was monitored using polarized light microscopy (PLM). It was found that the drastic decrease of the MW of cellulose did not result in improvement of its dissolution at room temperature. As compared to original cotton cellulose, the high amount of undissolved fibers in HC solutions led to unstable rheological behavior of HC solutions. Agglomeration and inhomogeneous dispersion of HC, and increased crystallinity, in this case, likely made the diffusion of BMIMAc/DMAc more difficult to the inside of the polymeric network of cellulose at ambient temperature, thereby hindering the dissolution. However, increasing the temperature from room temperature to 35 °C and 55 °C, led to a significant improvement in cellulose dissolution. This phenomenon implies that reducing the MW of cellulose might not be able to improve its dissolution under certain conditions. During the dissolution process, the physical properties of cellulose including fiber aggregation status, solvent diffusivity, and cellulose crystallinity may play a critical role compared to the MW, while the MW may not be an important factor. This finding may help further understand the mechanism of cellulose dissolution and seek better strategies to dissolve cellulose under mild conditions for industrial applications.
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Zhai, Shengcheng, Yoshiki Horikawa, Tomoya Imai, and Junji Sugiyama. "Cell wall ultrastructure of palm leaf fibers." IAWA Journal 35, no. 2 (2014): 127–37. http://dx.doi.org/10.1163/22941932-00000054.
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The cell wall organization of leaf sheath fibers in different palm species was studied with polarized light microscopy (PLM) and transmission electron microscopy (TEM). The secondary wall of the fibers consisted of only two layers, S1 and S2. The thickness of the S1 layer in leaf sheath fibers from the different palm species ranged from 0.31 to 0.90 μm, with a mean value of 0.57 μm, which was thicker than that of tracheids and fibers in secondary xylem of conifers and dicotyledons. The thickness of the S2 layer ranged from 0.44 to 3.43 μm, with a mean value of 1.86 μm. The ratio of S1 thickness to the whole cell wall thickness in palm fibers appears to be higher than in secondary xylem fibers and tracheids. The lignin in the fiber walls is very electron dense which makes it difficult to obtain high contrast of the different layers in the secondary wall. To clarify the cell wall layering with cellulose microfibrils in different orientations, the fibrovascular bundles of the windmill palm (Trachycarpus fortunei) were delignified with different reaction time intervals. The treated fibers were surveyed using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy analysis and TEM. The secondary fiber walls of windmill palm clearly showed only two layers at different reaction intervals with different lignin contents, even after almost all lignin was removed. We suggest that the two-layered structure in the secondary wall of palm leaf fibers, which presumably also applies to the homologous fibers in palm stems, is a specific character different from the fibers in other monocotyledons (such as bamboo and rattan) and dicot wood.
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Lessna, E., L. Bruning, C. Bolina, D. Lima, I. Watanabe, and A. Ciena. "Possible effects of the Agaricus brasiliensis extract on the cardiac morphology in mice." Journal of Morphological Sciences 32, no. 01 (2015): 016–21. http://dx.doi.org/10.4322/jms.069114.
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Abstract Introduction: Mushroom extracts are used, mainly due to immunomodulatory and antitumor proprierties. Among the general and species is the Agaricus brasiliensis or SunMushroom. However herbal remedies can cause changes in morphology and functionality of various organs. Therefore, these reporters need to be analyzed for applicability of this compound. The aim of the present study was to analyze the structural characteristics of the heart of Swiss mice employing light microscopy and scanning electron microscopy methods. Materials and methods: Swiss mice were used, divided into 2 groups: Control (n=6) and Agaricus brasiliensis (n=6), and the second group treated with the extract daily. After 60 days, under anesthesia withdrew from the samples, which were submitted to histological routine for obtaining serial sections. Results: Microscopic analysis revealed the aspects of the heart of Swiss mice: The formation of layers (epicardium, myocardium and endocardium) with partial view of the papillary muscles. Using the technique of Picro-Sirius: In yellow, the muscle fibers; in red, collagen fibers. Under polarized light, show the types of collagen fibers in red and green, significant collagen type I and III respectively. Conclusion: The arrangement of muscle fibers and collagen did not vary between the two groups.
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Smith, Z. D., M. J. Caplan, and J. D. Jamieson. "Immunocytochemical localization of plasmalemmal proteins in semi-thin sections of epithelial monolayers." Journal of Histochemistry & Cytochemistry 36, no. 3 (1988): 311–16. http://dx.doi.org/10.1177/36.3.2449492.
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We describe a technique for analysis by light microscopic immunocytochemistry of the distribution of plasmalemmal proteins in polarized epithelial cells. For this purpose, Madin Darby Canine Kidney (MDCK) cells were grown to confluency on Cytodex beads, the beads were fixed with formaldehyde, and semi-thin (0.5 micron) sections were cut at liquid nitrogen temperature on an ultracryomicrotome. The distribution of the basolaterally distributed plasmalemmal protein, Na,K-ATPase, was assessed by indirect immunofluorescence using a monospecific polyclonal antibody directed against the alpha-subunit of the Na pump. Such preparations enable epithelial monolayers to be evaluated in cross-section, thus permitting unambiguous topological assessment of apical and basolateral membrane proteins. Thus, the spatial uncertainties encountered in en face examination of membrane protein distribution in epithelia grown on solid supports are largely obviated. In addition, we describe a technique for removal of the bead matrix, which markedly reduces nonspecific background staining and improves access of reagents to the basal cell surface, thus permitting localization of basal lamina components.
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Thakkar, Rishi, Amit Raviraj Pillai, Jiaxiang Zhang, Yu Zhang, Vineet Kulkarni, and Mohammed Maniruzzaman. "Novel On-Demand 3-Dimensional (3-D) Printed Tablets Using Fill Density as an Effective Release-Controlling Tool." Polymers 12, no. 9 (2020): 1872. http://dx.doi.org/10.3390/polym12091872.
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This research demonstrates the use of fill density as an effective tool for controlling the drug release without changing the formulation composition. The merger of hot-melt extrusion (HME) with fused deposition modeling (FDM)-based 3-dimensional (3-D) printing processes over the last decade has directed pharmaceutical research towards the possibility of printing personalized medication. One key aspect of printing patient-specific dosage forms is controlling the release dynamics based on the patient’s needs. The purpose of this research was to understand the impact of fill density and interrelate it with the release of a poorly water-soluble, weakly acidic, active pharmaceutical ingredient (API) from a hydroxypropyl methylcellulose acetate succinate (HPMC-AS) matrix, both mathematically and experimentally. Amorphous solid dispersions (ASDs) of ibuprofen with three grades of AquaSolveTM HPMC-AS (HG, MG, and LG) were developed using an HME process and evaluated using solid-state characterization techniques. Differential scanning calorimetry (DSC), powder X-ray diffraction (pXRD), and polarized light microscopy (PLM) confirmed the amorphous state of the drug in both polymeric filaments and 3D printed tablets. The suitability of the manufactured filaments for FDM processes was investigated using texture analysis (TA) which showed robust mechanical properties of the developed filament compositions. Using FDM, tablets with different fill densities (20–80%) and identical dimensions were printed for each polymer. In vitro pH shift dissolution studies revealed that the fill density has a significant impact (F(11, 24) = 15,271.147, p < 0.0001) and a strong negative correlation (r > −0.99; p < 0.0001) with the release performance, where 20% infill demonstrated the fastest and most complete release, whereas 80% infill depicted a more controlled release. The results obtained from this research can be used to develop a robust formulation strategy to control the drug release from 3D printed dosage forms as a function of fill density.
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Piat, Romana, Siddharta Roy, and Alexander Wanner. "Material Parameter Identification of Interpenetrating Metal-Ceramic Composites." Key Engineering Materials 417-418 (October 2009): 53–56. http://dx.doi.org/10.4028/www.scientific.net/kem.417-418.53.
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A new class of metal/ceramic composites has recently been developed. A porous ceramic preform, the pore structure of which is created via a freeze-casting technique, is melt-infiltrated with metallic alloy via sqzeeze-casting. The microstructure of the composite has lamellar-like domains with geometrical characteristics which are dependent on the manufacturing parameters. The aim of our study is to find a good micromechanical model in order to deduce the mechanical properties of the single domains and of the whole material as a function of the microstructural geometry and the material parameters of the ceramics (alumina) and the alloy (Al-Si eutectic). Firstly, the statistical analysis of polarized light microscopic micrographs of the cross section of the specimen was performed. Domains with the same orientation of lamellae, so-called single domains were detected, selected and measured. The material modeling was performed by a two-step homogenisation procedure using a combination of different micromechanical models. Predicted material properties were compared with ultrasonic measurements for a single domain and for the whole microstructure.
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Pinheiro, J., D. O. Franco-Acuña, A. Oliveira-Menezes, et al. "Additional study of the morphology of eggs and miracidia of Eurytrema coelomaticum (Trematoda)." Helminthologia 52, no. 3 (2015): 244–51. http://dx.doi.org/10.1515/helmin-2015-0039.
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Abstract The morphology of the eggs and miracidia of Eurytrema coelomaticum was analyzed. The eggshell presented different composition according to the maturation stage of the egg, as seen by distinct birefringence after polarized light microscopic analysis. Detailed morphology of the brownish eggs, measuring 44.97±3.83 (38.67 - 51.40) μm in length and 30.71±2.54 (25.79 -34.47) μm in width, and the different electrondensities of the inner, middle and outer layers of the eggs were determined using light (bright field and DIC) and electronic microscopy (scanning and transmission). The morphometry of the eggs is in accordance to those measures presented in previous studies. The miracidia were observed using light microscopy, inside and outside the egg. It was possible to observe the terebratorium at the anterior end of the body, the ciliated epidermal plates, placed according the formula E=2E1 + 2E2, and the interepidermal ridge, but eyespots were not observed. The excretory vesicle was laterally placed in the posterior middle of the body and the germ balls were observed. The miracidium inside the egg was observed by routine techniques, but the miracidium was not well preserved. Thus, the eggs were processed using high pressure-freeze substitution technique and reasonable preservation was achieved. The cilia covering the larval body, with a typical ciliary organization, the terebratorium with folds and the junction of the epidermal ciliated cell with the larval body were seen. For the first time detailed information on the eggs and miracidia of E. coelomaticum is given, which can be the basis for new studies.
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Meyer, Arne, Karsten Dierks, and Christian Betzel. "Depolarized Dynamic Light Scattering a method to analyse Particle Shape and Size." Acta Crystallographica Section A Foundations and Advances 70, a1 (2014): C1749. http://dx.doi.org/10.1107/s2053273314082503.
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"Dynamic Light Scattering (DLS) is already a widely used method for small particle size distribution analysis [1]. The main purpose of this method is the determination of particle sizes, respectively the hydrodynamic radius in the sub-microscopic range, i.e. 1 nm up to few µm. It is based on the Brownian motion of those particles. Light scattering methods are non-invasive and therefore a great advantage in the field of particle analysis [2a]. The next generation of Dynamic Light Scattering devices will apply depolarized dynamic light scattering (DDLS) [2b]. This technique allows to obtain beside radius distributions also information about the particle shape. However, for some time technical drawbacks made it almost unfeasible to use it for biological samples. In cooperation with the University of Hamburg we developed the first experimental set-up of a DDLS system to be used in the laboratory to analyze and characterize protein solutions as well as suspensions of nano crystals, suitable for Free-Electron-Laser applications. The fundamental difference to so far known ""standard"" DLS is that the scattered light is separated into two signal pathways, a vertically and a horizontally polarized component, applying a special designed beam splitter. DDLS allows to measure the translational diffusion and the rotational constants simultaneously. Both constants are derived from the decay times of the autocorrelation functions. With the equations of Perrin the system is capable of calculating the axis ratio of the particles, approximating the real particle shape as a rotational ellipsoid. For calibration and tests gold rod particles of 575 nm in length and 25 nm diameter were applied. The first biological sample, which was analyzed by DDLS was hemocyanin from Limulus polyphemus hemolymph [3a], which occurrs predominantly as hexamers, dodecamers and traces of higher aggregates occur at high pH. In summary, together with additional advantages like viscosity independent measurements and ten times higher resolution compared to DLS, the DDLS-technique is optimal to characterize biological samples to be used for crystallization experiments and to score solutions and suspensions of nano-crystals to be used for Free-Electron Laser applications [3b]."