Articoli di riviste: "Electron microscopy Methodology"

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Iha, Luiz Cesar Nakao, Andre Aguillera, Flavio Faria, Cristiane Akemi Kasse, Oswaldo Laercio Mendonça Cruz e Edna Frey Muller. "R147: Scanning Electron Microscopy: Alternatives in Methodology". Otolaryngology–Head and Neck Surgery 135, n. 2_suppl (agosto 2006): P156. http://dx.doi.org/10.1016/j.otohns.2006.06.901.

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Downing, Kenneth H. "Instrumentation and methodology for electron crystallography". Proceedings, annual meeting, Electron Microscopy Society of America 49 (agosto 1991): 420–21. http://dx.doi.org/10.1017/s0424820100086404.

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The determination of three-dimensional structures of macromolecules at atomic resolution remains one oμf the great promises of electron microscopy. Instrumental problems which had to be overcome in order to achieve single-atom resolution have long been recognized and to a large extent overcome. It is interesting to note that most of the instrumental developments were already incorporated in a microscope under construction over 20 years ago. However, the application of techniques to circumvent limitations imposed by the sensitivity of organic specimen to radiation damage are still developing. Electron crystallography, which takes advantage of the ability to obtain useful information from images taken at very low exposure, is close to realizing the potential. The state of electron crystallography has advanced rapidly during the last few years. The structure of one protein, bacteriorhodopsin, has been determined from EM data, and several other structures are advanced to the point of fitting the peptide chain to a high-resolution density map.

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Liang, Alice F., Chris Petzold, Kristen Dancel-Manning, Yan Deng e Michael Cammer. "Methodology Development at NYULMC Microscopy Core - Correlative Light and Electron Microscopy Applications". Microscopy and Microanalysis 21, S3 (agosto 2015): 879–80. http://dx.doi.org/10.1017/s143192761500519x.

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Leppard, GG, A. Heissenberger e GJ Herndl. "Ultrastructure of marine snow. I. Transmission electron microscopy methodology". Marine Ecology Progress Series 135 (1996): 289–98. http://dx.doi.org/10.3354/meps135289.

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Danev, Radostin, Haruaki Yanagisawa e Masahide Kikkawa. "Cryo-Electron Microscopy Methodology: Current Aspects and Future Directions". Trends in Biochemical Sciences 44, n. 10 (ottobre 2019): 837–48. http://dx.doi.org/10.1016/j.tibs.2019.04.008.

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Sicignano, A., e M. Vaez Iravani. "Methodology and practice of in situ differential scanning electron microscopy". Scanning 12, n. 2 (1990): 61–68. http://dx.doi.org/10.1002/sca.4950120203.

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Asher, Lucas, e Jessica Hata. "Platelet Electron Microscopy: Utilizing LEAN Methodology to Optimize Laboratory Workflow". Pediatric and Developmental Pathology 23, n. 5 (19 maggio 2020): 356–61. http://dx.doi.org/10.1177/1093526620915361.

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Background Platelet electron microscopy (PEM) is the gold standard methodology for diagnosing storage pool disorder, defined as a paucity of delta granules, alpha granules, or both. PEM literature is limited with few published resources and without well-developed interlaboratory standardization for the preparation and examination of platelet samples. Methods Whole mount (WM) dense body (DB) counts for 300 pediatric cases were reviewed to determine whether counting fewer platelets could yield the same results. For 6 cases, DB average was determined on the day of WM preparation and on 2 consecutive days. Both WM and thin section (TS) preparations were examined for all cases. Results Employing LEAN methodology, an algorithm was developed to markedly decrease the number of platelets counted and still ensure accurate results. WMs decay with time; a statistically significant difference in DB counts was noted between day 0 and day 1 ( p < .1). Twelve of 300 cases required both WM and TS preparations for a complete diagnosis. Conclusion It is possible to maintain accuracy and decrease 100 platelet DB counts by >75%. WMs must be counted on the day they are prepared to avoid false paucity of DB secondary to sample decay. An accurate evaluation of platelet morphology requires both the WM and TS techniques.

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Kammers, A. D., e S. Daly. "Digital Image Correlation under Scanning Electron Microscopy: Methodology and Validation". Experimental Mechanics 53, n. 9 (11 luglio 2013): 1743–61. http://dx.doi.org/10.1007/s11340-013-9782-x.

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Menteş, T. O., G. Zamborlini, A. Sala e A. Locatelli. "Cathode lens spectromicroscopy: methodology and applications". Beilstein Journal of Nanotechnology 5 (27 ottobre 2014): 1873–86. http://dx.doi.org/10.3762/bjnano.5.198.

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The implementation of imaging techniques with low-energy electrons at synchrotron laboratories allowed for significant advancement in the field of spectromicroscopy. The spectroscopic photoemission and low energy electron microscope, SPELEEM, is a notable example. We summarize the multitechnique capabilities of the SPELEEM instrument, reporting on the instrumental aspects and the latest developments on the technical side. We briefly review applications, which are grouped into two main scientific fields. The first one covers different aspects of graphene physics. In particular, we highlight the recent work on graphene/Ir(100). Here, SPELEEM was employed to monitor the changes in the electronic structure that occur for different film morphologies and during the intercalation of Au. The Au monolayer, which creeps under graphene from the film edges, efficiently decouples the graphene from the substrate lowering the Dirac energy from 0.42 eV to 0.1 eV. The second field combines magnetism studies at the mesoscopic length scale with self-organized systems featuring ordered nanostructures. This example highlights the possibility to monitor growth processes in real time and combine chemical characterization with X-ray magnetic circular dichroism–photoemission electron microscopy (XMCD–PEEM) magnetic imaging by using the variable photon polarization and energy available at the synchrotron source.

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Yang, Jinfeng, e Yoichi Yoshida. "Relativistic Ultrafast Electron Microscopy: Single-Shot Diffraction Imaging with Femtosecond Electron Pulses". Advances in Condensed Matter Physics 2019 (2 maggio 2019): 1–6. http://dx.doi.org/10.1155/2019/9739241.

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We report on a single-shot diffraction imaging methodology using relativistic femtosecond electron pulses generated by a radio-frequency acceleration-based photoemission gun. The electron pulses exhibit excellent characteristics, including a root-mean-square (rms) illumination convergence of 31 ± 2 μrad, a spatial coherence length of 5.6 ± 0.4 nm, and a pulse duration of approximately 100 fs with (6.3 ± 0.6) × 106 electrons per pulse at 3.1 MeV energy. These pulses facilitate high-quality diffraction images of gold single crystals with a single shot. The rms spot width of the diffracted beams was obtained as 0.018 ± 0.001 Å−1, indicating excellent spatial resolution.

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Chudnovsky, A., K. Sehanobish e S. Wu. "Methodology for Durability Analysis of HDPE Pipe". Journal of Pressure Vessel Technology 122, n. 2 (15 dicembre 1999): 152–55. http://dx.doi.org/10.1115/1.556165.

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Toughness evaluation and durability analysis are two of the critical steps to design a toughened HDPE resin for durability in pipe applications. Durability analysis involves defect characterization, crack initiation and propagation mechanism, and long-term performance prediction. The methodology for durability analysis of high-density polyethylene (HDPE) pipe will be discussed in this paper. Various analytical techniques, such as fractography, hot-stage microscopy, energy-dispersive X-ray (EDX), microtransmittance infrared spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), have been used to characterize the defect properties and size distribution. Crack initiation and propagation mechanisms in HDPE have been analyzed by some accelerated tests and compared with that observed in the long-term hydrostatic pressure test. A new procedure for lifetime prediction of HDPE under creep is discussed based on the crack layer theory (Chudnovsky, A., 1984, NASA Contractor Report 174634). [S0094-9930(00)00802-7]

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Kaushik, Madhu, Wei C. Chen, Theo G. M. van de Ven e Audrey Moores. "An improved methodology for imaging cellulose nanocrystals by transmission electron microscopy". Nordic Pulp & Paper Research Journal 29, n. 1 (1 gennaio 2014): 77–84. http://dx.doi.org/10.3183/npprj-2014-29-01-p077-084.

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Smith, Paul, John Gannon e Frank Eggert. "A New Methodology for Element Imaging in the Scanning Electron Microscope". Microscopy and Microanalysis 7, S2 (agosto 2001): 1054–55. http://dx.doi.org/10.1017/s1431927600031342.

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The analysis of samples with a scanning electron microscope often requires element distribution images. Until recently, element mapping was strongly limited by the count rate that could be processed with conventional EDS systems using Si(Li) or Ge crystal diode detectors. The enhancement of secondary and backscattered SEM images can now be achieved through the addition of rapid color imaging. Using a new methodology for color enhancement, features as small as 1 micrometer can be colored and easily distinguished. The addition of color to SEM images enables easy visualization of element distributions and allows the microstructural features and compositional variations of different materials to be more readily identified. Persons unfamiliar with electron microscopy can more readily interpret color images than black and white or gray scale images. This new technology for imaging elements has great potential to revolutionize electron microscopy.The detector technology behind this new methodology is the silicon drift diode (SDD).

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Conforto, Egle, Nicolas Joguet, Pierre Buisson, Jean-Eudes Vendeville, Carine Chaigneau e Thierry Maugard. "An optimized methodology to analyze biopolymer capsules by environmental scanning electron microscopy". Materials Science and Engineering: C 47 (febbraio 2015): 357–66. http://dx.doi.org/10.1016/j.msec.2014.11.054.

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Login, G. R., W. B. Stavinoha e A. M. Dvorak. "Ultrafast microwave energy fixation for electron microscopy." Journal of Histochemistry & Cytochemistry 34, n. 3 (marzo 1986): 381–87. http://dx.doi.org/10.1177/34.3.3950387.

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We demonstrate that microwave (MW) energy can be used in conjunction with chemical cross-linking agents to fix tissue blocks rapidly for electron microscopy in as brief a time as 26 msec. The optimal ultrafast MW fixation methodology involved immersing tissue blocks up to 2 mm3 in dilute aldehyde fixative and immediately irradiating the specimens in a 7.3 kW MW oven for 26-90 msec, reaching a fixation temperature range of 32-42 degrees C. Ultrastructural preservation of samples irradiated by MW energy was comparable to that of the control samples immersed in aldehyde fixative for 2 hr at 25 degrees C. Potential applications for this new fixation technology include investigation of rapid intracellular processes (e.g., vesicular transport) and preservation of proteins that are difficult to demonstrate with routine fixation methods (e.g., antigens and enzymes).

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Drab, Marek, Janusz Krajniak e Krzysztof P. Grzelakowski. "The New Methodology and Chemical Contrast Observation by Use of the Energy-Selective Back-Scattered Electron Detector". Microscopy and Microanalysis 22, n. 6 (dicembre 2016): 1369–73. http://dx.doi.org/10.1017/s1431927616012514.

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AbstractWe report on a robust method for chemical element-sensitive imaging by scanning electron microscopy (SEM). The commercial Auriga FE-SEM microscope (Carl Zeiss, Oberkochen, Germany), equipped with an energy-selective grid detector (EsB) as a part of the experimental setup, was applied for generation of chemical contrast at low accelerating voltages, which is gentle for sensitive samples. The EsB-grid detector, conceptually adapted by us as an energy retarding field analyzer (RFA), was used to detect the two-dimensional (2D) energy spectrum for the first time. The electron energy spectrum measured by sweeping the retarding grid potential revealed thresholds corresponding to electronic transitions in the specimen, followed by 2D-derivation treatment applied just at the observed thresholds. This allowed chemical mapping by SEM. In this report the 273 eV Auger transition in carbon deposited onto the Si(100) sample was chosen as a source for chemical contrast in the SEM image. In addition to Auger electrons, we expect analogous energy-selective contrast enhancement for inelastically scattered electrons, for example, in plasmonic contrast and elastically scattered electrons, for example in phase contrast, our method, proved for carbon, is expected to apply to a broader list of elements as a general capability of chemical mapping, at several-fold better lateral resolution when compared with energy dispersive spectroscopy (EDS).

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Baumann, Frieder, Pradip Sairam Pichumani e Christopher Torcedo. "Innovative Grounding Methodology for Epoxy Impregnated Semiconductor Cross Sections for Electron Microscopy Inspection". Microscopy and Microanalysis 26, S2 (30 luglio 2020): 370–72. http://dx.doi.org/10.1017/s1431927620014415.

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Tufvesson, Bertil, e Torsten Johnsson. "IMMUNOELECTROOSMOPHORESIS FOR DETECTION OF REO-LIKE VIRUS: METHODOLOGY AND COMPARISON WITH ELECTRON MICROSCOPY". Acta Pathologica Microbiologica Scandinavica Section B Microbiology 84B, n. 4 (15 agosto 2009): 225–28. http://dx.doi.org/10.1111/j.1699-0463.1976.tb01929.x.

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Yurtsever, Aycan, Renske M. van der Veen e Ahmed H. Zewail. "Subparticle Ultrafast Spectrum Imaging in 4D Electron Microscopy". Science 335, n. 6064 (5 gennaio 2012): 59–64. http://dx.doi.org/10.1126/science.1213504.

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Single-particle imaging of structures has become a powerful methodology in nanoscience and molecular and cell biology. We report the development of subparticle imaging with space, time, and energy resolutions of nanometers, femtoseconds, and millielectron volts, respectively. By using scanning electron probes across optically excited nanoparticles and interfaces, we simultaneously constructed energy-time and space-time maps. Spectrum images were then obtained for the nanoscale dielectric fields, with the energy resolution set by the photon rather than the electron, as demonstrated here with two examples (silver nanoparticles and the metallic copper–vacuum interface). This development thus combines the high spatial resolution of electron microscopy with the high energy resolution of optical techniques and ultrafast temporal response, opening the door to various applications in elemental analysis as well as mapping of interfaces and plasmonics.

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Zehbe, Rolf, Astrid Haibel, Heinrich Riesemeier, Ulrich Gross, C. James Kirkpatrick, Helmut Schubert e Christoph Brochhausen. "Going beyond histology. Synchrotron micro-computed tomography as a methodology for biological tissue characterization: from tissue morphology to individual cells". Journal of The Royal Society Interface 7, n. 42 (25 marzo 2009): 49–59. http://dx.doi.org/10.1098/rsif.2008.0539.

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Current light microscopic methods such as serial sectioning, confocal microscopy or multiphoton microscopy are severely limited in their ability to analyse rather opaque biological structures in three dimensions, while electron optical methods offer either a good three-dimensional topographic visualization (scanning electron microscopy) or high-resolution imaging of very thin samples (transmission electron microscopy). However, sample preparation commonly results in a significant alteration and the destruction of the three-dimensional integrity of the specimen. Depending on the selected photon energy, the interaction between X-rays and biological matter provides semi-transparency of the specimen, allowing penetration of even large specimens. Based on the projection-slice theorem, angular projections can be used for tomographic imaging. This method is well developed in medical and materials science for structure sizes down to several micrometres and is considered as being non-destructive. Achieving a spatial and structural resolution that is sufficient for the imaging of cells inside biological tissues is difficult due to several experimental conditions. A major problem that cannot be resolved with conventional X-ray sources are the low differences in density and absorption contrast of cells and the surrounding tissue. Therefore, X-ray monochromatization coupled with a sufficiently high photon flux and coherent beam properties are key requirements and currently only possible with synchrotron-produced X-rays. In this study, we report on the three-dimensional morphological characterization of articular cartilage using synchrotron-generated X-rays demonstrating the spatial distribution of single cells inside the tissue and their quantification, while comparing our findings to conventional histological techniques.

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Takizawa, Toshihiro, e John M. Robinson. "FluoroNanogold Is a Bifunctional Immunoprobe for Correlative Fluorescence and Electron Microscopy". Journal of Histochemistry & Cytochemistry 48, n. 4 (aprile 2000): 481–85. http://dx.doi.org/10.1177/002215540004800405.

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We applied a fluorescent ultrasmall immunogold probe, FluoroNanogold (FNG), to immunocytochemistry on ultrathin cryosections. FNG has the properties of both a fluorescent dye-conjugated antibody for fluorescence microscopy and a gold particle-conjugated antibody for electron microscopy. Therefore, this bifunctional immunoprobe permits correlative microscopic observation of the same cell profiles labeled in a single labeling procedure by these two imaging methods. We demonstrate the utility of FNG as a secondary antibody for immunocytochemical labeling of myeloperoxidase (a marker protein for azurophilic granules) in ultrathin cryosectioned human neutrophils. Its detection requires high spatial resolution because neutrophils contain many cytoplasmic granules. There was a one-to-one relationship between fluorescent structures labeled with FNG and organelle profiles labeled with the same silver-enhanced FNG in ultrathin cryosections. Use of FNG immunocytochemistry on ultrathin cryosections is an ideal methodology for highresolution correlative fluorescence and electron microscopy and can provide unique information that may be difficult to obtain with a single imaging regimen.

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Castroviejo, R., E. Berrezueta e R. Lastra. "Microscopic digital image analysis of gold ores: a critical test of methodology, comparing reflected light and electron microscopy". Mining, Metallurgy & Exploration 19, n. 2 (maggio 2002): 102–9. http://dx.doi.org/10.1007/bf03403263.

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Dejgaard, Selma Yilmaz, Ayesha Murshid, Kristina M. Dee e John F. Presley. "Confocal Microscopy-based Linescan Methodologies for Intra-Golgi Localization of Proteins". Journal of Histochemistry & Cytochemistry 55, n. 7 (19 marzo 2007): 709–19. http://dx.doi.org/10.1369/jhc.6a7090.2007.

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Localization of resident Golgi proteins to earlier ( cis) or later ( trans) Golgi compartments has traditionally required quantitative immunocytochemistry and electron microscopy, which are inaccessible to many researchers. For this reason, light microscopy has often been used, initially for localization of Golgi glycotransferases and, more recently, for other Golgi proteins (e.g., Arf1, GBF1, Rab6). Quantitation of light microscopic intra-Golgi localization can be problematic. We describe here a novel quantitative light microscopic methodology using linescans crossing the Golgi ribbon. Our method determines a localization for the unknown protein in a one-dimensional coordinate system in which 0.0 corresponds to localization of a cis marker and 1.0 to localization of a trans marker. We also describe a variant of this methodology in which Golgi morphology is simplified by nocodazole-induced dispersal into ministacks, allowing a fully automated analysis. In our assay, β1,4-galactosyltransferase-YFP and Golgin97 localize similarly to trans markers, whereas p115, GBF1, and p58-YFP are similarly near other cis markers. The medial Golgi protein α1,3–1,6-mannosidase II gives an intermediate localization in this assay. These methodologies may prove useful in instances where electron microscopy is technically difficult as well as when rapid analysis of large numbers of samples is required.

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Sakamoto, Hirotaka, e Mitsuhiro Kawata. "Ultrahigh Voltage Electron Microscopy Links Neuroanatomy and Neuroscience/Neuroendocrinology". Anatomy Research International 2012 (8 dicembre 2012): 1–5. http://dx.doi.org/10.1155/2012/948704.

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The three-dimensional (3D) analysis of anatomical ultrastructures is extremely important in most fields of biological research. Although it is very difficult to perform 3D image analysis on exact serial sets of ultrathin sections, 3D reconstruction from serial ultrathin sections can generally be used to obtain 3D information. However, this technique can only be applied to small areas of a specimen because of technical and physical difficulties. We used ultrahigh voltage electron microscopy (UHVEM) to overcome these difficulties and to study the chemical neuroanatomy of 3D ultrastructures. This methodology, which links UHVEM and light microscopy, is a useful and powerful tool for studying molecular and/or chemical neuroanatomy at the ultrastructural level.

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Goheen, Michael P., Marilyn S. Bartlett e James W. Smith. "Immunogold labeling of Pneumocystis carinii for Electron microscopy". Proceedings, annual meeting, Electron Microscopy Society of America 49 (agosto 1991): 270–71. http://dx.doi.org/10.1017/s0424820100085654.

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Studies of the biology of Pneumocystis carinii (PC) are of increasing importance because this extracellular pathogen is a frequent source of severe pneumonia in patients with acquired immunodeficiency syndrome (AIDS) and is a leading cause of mortality in these patients. Immunoelectron microscopic localization of antigenic sites on the surface of PC would improve the understanding of these sites and their role in pathenogenisis of the disease and response to chemotherapy. The purpose of this study was to develop a methodology for visualizing immunoreactive sites on PC with transmission electron microscopy (TEM) using immunogold labeled probes.Trophozoites of PC were added to spinner flask cultures and allowed to grow for 7 days, then aliquots of tissue culture fluid were centrifuged at 12,000 RPM for 30 sec. Pellets of organisims were fixed in either 1% glutaraldehyde, 0.1% glutaraldehyde-4% paraformaldehyde, or 4% paraformaldehyde for 4h. All fixatives were buffered with 0.1M Na cacodylate and the pH adjusted to 7.1. After fixation the pellets were rinsed in 0.1M Na cacodylate (3X), dehydrated with ethanol, and immersed in a 1:1 mixture of 95% ethanol and LR White resin.

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Hayakawa, Eri H., e Hiroyuki Matsuoka. "Detailed methodology for high resolution scanning electron microscopy (SEM) of murine malaria parasitized-erythrocytes". Parasitology International 65, n. 5 (ottobre 2016): 539–44. http://dx.doi.org/10.1016/j.parint.2016.03.006.

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Stoeck, Thorsten, William H. Fowle e Slava S. Epstein. "Methodology of Protistan Discovery: from rRNA Detection to Quality Scanning Electron Microscope Images". Applied and Environmental Microbiology 69, n. 11 (novembre 2003): 6856–63. http://dx.doi.org/10.1128/aem.69.11.6856-6863.2003.

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ABSTRACT Each year, thousands of new protistan 18S rRNA sequences are detected in environmental samples. Many of these sequences are molecular signatures of new protistan species, classes, and/or kingdoms that have never been seen before. The main goal of this study was to enable visualization of these novel organisms and to conduct quality ultrastructural examination. We achieved this goal by modifying standard procedures for cell fixation, fluorescence in situ hybridization, and scanning electron microscopy (SEM) and by making these methodologies work in concert. As a result, the same individual cell can now be detected by 18S rRNA-targeted fluorochrome-labeled probes and then viewed by SEM to reveal its diagnostic morphological characteristics. The method was successfully tested on a wide range of protists (alveolates, stramenopiles, kinetoplastids, and cryptomonads). The new methodology thus opens a way for fine microscopy studies of many organisms previously known exclusively by their 18S rRNA sequences.

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Bykov, Yury S., Nir Cohen, Natalia Gabrielli, Hetty Manenschijn, Sonja Welsch, Petr Chlanda, Wanda Kukulski, Kiran R. Patil, Maya Schuldiner e John A. G. Briggs. "High-throughput ultrastructure screening using electron microscopy and fluorescent barcoding". Journal of Cell Biology 218, n. 8 (9 luglio 2019): 2797–811. http://dx.doi.org/10.1083/jcb.201812081.

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Genetic screens using high-throughput fluorescent microscopes have generated large datasets, contributing many cell biological insights. Such approaches cannot tackle questions requiring knowledge of ultrastructure below the resolution limit of fluorescent microscopy. Electron microscopy (EM) reveals detailed cellular ultrastructure but requires time-consuming sample preparation, limiting throughput. Here we describe a robust method for screening by high-throughput EM. Our approach uses combinations of fluorophores as barcodes to uniquely mark each cell type in mixed populations and correlative light and EM (CLEM) to read the barcode of each cell before it is imaged by EM. Coupled with an easy-to-use software workflow for correlation, segmentation, and computer image analysis, our method, called “MultiCLEM,” allows us to extract and analyze multiple cell populations from each EM sample preparation. We demonstrate several uses for MultiCLEM with 15 different yeast variants. The methodology is not restricted to yeast, can be scaled to higher throughput, and can be used in multiple ways to enable EM to become a powerful screening technique.

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Kang, J., M. Jain, D. S. Wilkinson e J. D. Embury. "Microscopic Strain Mapping Using Scanning Electron Microscopy Topography Image Correlation at Large Strain". Journal of Strain Analysis for Engineering Design 40, n. 6 (1 agosto 2005): 559–70. http://dx.doi.org/10.1243/030932405x16151.

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Measuring the distribution of local strain at the microscopic level is a challenging problem, especially for materials subjected to large overall strain. In the present study, a novel microscopic strain mapping technique has been developed based on the analysis of surface topography using digital image correlation (DIC) software. The input is a series of scanning electron microscopy (SEM) images. The method uses topographic features (such as surface slip traces) found in these images as the input. A commercially available optical strain measurement system (ARAMIS®, which is a trade name of the equipment from GOM mbH, Braunschweig, Germany) that utilizes the DIC methodology is used for this purpose. It was found that the best results were obtained using an incremental approach in which DIC is used to map the local strain increments following a modest amount of macroscopic deformation. This is essential when using topographic features such as slip traces that are not static. The accuracy and scale of the measurements are affected by image and facet size. The method has been validated, based on in situ deformation of an aluminium alloy within an SEM, using strains measured independently by means of surface indents. The results clearly reveal the details of the local shear on a sub-grain-size scale and the evolution of shear bands within the necking area, leading to local strains that exceed the average strain by a factor of 2.3.

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Arnold, Christopher, Christoph Pobel, Fuad Osmanlic e Carolin Körner. "Layerwise monitoring of electron beam melting via backscatter electron detection". Rapid Prototyping Journal 24, n. 8 (12 novembre 2018): 1401–6. http://dx.doi.org/10.1108/rpj-02-2018-0034.

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Purpose The purpose of this study is the introduction and validation of a new technique for process monitoring during electron beam melting (EBM). Design/methodology/approach In this study, a backscatter electron detector inside the building chamber is used for image acquisition during EBM process. By systematic variation of process parameters, the ability of displaying different topographies, especially pores, is investigated. The results are evaluated in terms of porosity and compared with optical microscopy and X-ray computed tomography. Findings The method is capable of detecting major flaws (e.g. pores) and gives information about the quality of the resulting component. Originality/value Image acquisition by evaluating backscatter electrons during EBM process is a new approach in process monitoring which avoids disadvantages restricting previously investigated techniques.

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Taheri, Shima, Martin Ams, Heriberto Bustamante, Louisa Vorreiter, Michael Withford e Simon Martin Clark. "A practical methodology to assess corrosion in concrete sewer pipes". MATEC Web of Conferences 199 (2018): 06010. http://dx.doi.org/10.1051/matecconf/201819906010.

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The combination of Neutron Tomography (NT), Scanning Electron Microscopy (SEM, with and without elemental analysis), pH profiling and Microindentation Mapping techniques was used to develop a methodology for the assessment of concrete sewer pipe deterioration. We demonstrate a viable method for health monitoring of concrete sewer pipes and the evaluation of competing mitigation strategies.

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Duan, Heng-Zhi, Hong-Yan Zeng, Hua-Miao Xiao, Chao-Rong Chen, Gao-Fei Xiao e Quan Zhao. "Optimization of ammonia nitrogen removal by SO42− intercalated hydrotalcite using response surface methodology". RSC Advances 6, n. 54 (2016): 48329–35. http://dx.doi.org/10.1039/c6ra08321h.

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SO₄²⁻ intercalated Mg–Al hydrotalcite (S-LDH) was prepared under microwave irradiation and characterized by powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM).

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Rzepiejewska-Malyska, K. A., W. M. Mook, M. Parlinska-Wojtan, J. Hejduk e J. Michler. "In situ scanning electron microscopy indentation studies on multilayer nitride films: Methodology and deformation mechanisms". Journal of Materials Research 24, n. 3 (marzo 2009): 1208–21. http://dx.doi.org/10.1557/jmr.2009.0139.

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Systematic studies of the deformation mechanisms of multilayer transition metal nitride coatings TiN/CrN, TiN/NbN, and NbN/CrN, and corresponding reference coatings of TiN, NbN, and CrN deposited by a direct current (dc) magnetron sputtering process onto silicon 〈100〉 have been performed. Mechanical characterization was conducted using a combination of microindentation and nanoindentation in the load range 30 to 150 mN and 0.5 to 3.5 mN, respectively. For both load ranges, scanning electron microscopy (SEM) in situ indentation was used to observe the indentation process including any pileup, sink-in, and fracture mechanisms specific to each coating. The coatings’ microstructure, both before and after indentation, was analyzed using transmission electron microscopy (TEM). It was possible to both correlate the indentation load–displacement response to surface roughness effects and fracture modes (substrate and film cracking) and observe deformation mechanisms within the coatings.

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Stanley, Shena M., Amartya Chakrabarti, Joshua J. DeMuth, Vanessa E. Tempel e Narayan S. Hosmane. "Catalyst-Free Bottom-Up Synthesis of Few-Layer Hexagonal Boron Nitride Nanosheets". Journal of Nanomaterials 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/304295.

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A novel catalyst-free methodology has been developed to prepare few-layer hexagonal boron nitride nanosheets using a bottom-up process. Scanning electron microscopy and transmission electron microscopy (both high and low resolution) exhibit evidence of less than ten layers of nanosheets with uniform dimension. X-ray diffraction pattern and other additional characterization techniques prove crystallinity and purity of the product.

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da Silva, Marcelo A., José Claudio G. Teixeira, Ari Sauer Guimarães, Ivani S. Bott e Hector R. M. Costa. "A Methodology for Evaluation of Life Fraction Using Cr-Mo Steel under Creep Conditions". Materials Science Forum 758 (giugno 2013): 57–63. http://dx.doi.org/10.4028/www.scientific.net/msf.758.57.

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The quantification methodology used to predict the residual life of Cr-Mo steel was microstructure/life fraction correlation under creep conditions. Microstructural evolution has been correlated with accelerated creep testing progress during testing at constant load and a temperature of 600°C, as well as with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. Experimental results from TEM revealed six distinct stages, which were directly related to the life fraction values obtained. However, in the case of MEV, five stages were found. This difference is likely due to the better analysis possible via TEM of both microstructural evolution and types of carbides formed during the creep process. In addition, an evolution map is proposed to allow for easy interpretation of the relationship between microstructural characteristics and life fraction.

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Wang, Haifeng, Jason Fang, Jason Arjavac e Rudy Kellner. "Scanning Transmission Electron Microscopy for Critical Dimension Monitoring in Wafer Manufacturing". Microscopy Today 16, n. 1 (gennaio 2008): 24–27. http://dx.doi.org/10.1017/s1551929500054298.

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Automated scanning transmission electron microscopy (STEM) metrology provides critical dimension (CD) measurements an order of magnitude more precise than comparable scanning electron microscopy (SEM) measurements. New developments in automation now also provide throughput and response time sufficient to support high volume microelectronic manufacturing processes. The newly developed methodology includes automated, focused ion beam (FIB) based sample preparation; innovative, ex-situ sample extraction; and automated metrology. Although originally developed to control the production of thin film magnetic heads for data storage, the technique is fully applicable to any wafer-based manufacturing process.

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Baker, T. S., e D. A. Winkelmann. "Methodology for determining the three-dimensional crystal structure of myosin Sl from electron microscopy of orthogonal thin sections". Proceedings, annual meeting, Electron Microscopy Society of America 44 (agosto 1986): 26–29. http://dx.doi.org/10.1017/s0424820100141895.

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Detailed knowledge of the structure of myosin is essential for understanding the mechanism of muscle contraction. The discovery of conditions for crystallizing the head of myosin (Sl = subfragment 1) has led to systematic studies of the SI structure by x-ray crystallography and electron microscopy. We describe the method used to determine the structure of the myosin Sl molecule by electron microscopy (Fig. 3). This method involved independently reconstructing the three-dimensional density of several thin sections obtained from oriented crystals and then combining these reconstructions to produce a final, averaged density map of a single unit cell.

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Cone, Kim A., Richard F. Wendlandt, Katharina Pfaff e Omero F. Orlandini. "Texture constraints on crystal size distribution methodology: An application to the Laki fissure eruption". American Mineralogist 105, n. 5 (1 maggio 2020): 585–98. http://dx.doi.org/10.2138/am-2020-7007.

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Abstract Modeling crystal size distributions often requires the extraction of 2D discrete crystal lengths to calculate 3D volumetric equivalences. These apparent lengths are obtained from digital images that exploit different physical and chemical characteristics of samples, and the choice of image type can affect the interpretation of crystal length measurements, thus affecting crystal size distribution modeling. To examine method- and texture-based effects on extracting crystal size distributions, we obtained plagioclase length measurements from two texturally opposing basaltic lava samples from the well-documented Laki fissure eruptions of 1783–1784. Using approaches that consider inherent texture-based limitations of 2D image types, we employed manual tracing and imaging software to extract plagioclase crystal lengths from three types of images: (1) photomicrographs from polarized-light microscopy, (2) backscatter electron images from scanning electron microscopy, and (3) energy-dispersive X-ray maps from automated mineralogy. Our results demonstrate that (1) phenocrysts (L ≥ 150 μm) and groundmass plagioclase (L < 150 μm) in our basalt samples appear with multiple aspect ratios, while the latter also display greater nucleation densities as crystal size population are continuously refined over increasingly smaller crystal lengths; (2) complex crystal clusters must be manually dissected into their discrete crystal components to produce meaningful crystal size distributions; (3) localized electron backscatter diffraction analysis reveals mild preferred orientation in complex clusters and groundmass, the latter confirmed by variations in crystal size distributions between orthogonal backscatter electron images; and (4) method-induced variations in both aspect ratio and crystal length determination can produce a wide range of kinetic interpretations that pose challenges for cross-research comparisons. For phenocrysts, compensating for clustering and fracturing through manual tracing remains the most effective method, while groundmass populations can be addressed with high-resolution (micrometer-scale) automated scanning electron microscopy for deciphering late-stage eruptive behavior. A texture-focused protocol should be established, as any kinetic information derived from crystal size distribution analyses across multiple studies employing multiple approaches cannot otherwise be directly compared.

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Yi, Hong, Rahmat Peijper e Jan LM Leunissen. "Methodology Advancements in Electron Microscopy Immunolabeling of Hydrated Brain Tissue Using Subnanometer Colloidal Gold Conjugates". Microscopy and Microanalysis 8, S02 (agosto 2002): 126–27. http://dx.doi.org/10.1017/s1431927602101644.

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Ebrahimi, Shamsi, Coswald Stephen Sipaut@ Mohd Nasri e Sazmal Effendi Bin Arshad. "Hydrothermal synthesis of hydroxyapatite powders using Response Surface Methodology (RSM)". PLOS ONE 16, n. 5 (20 maggio 2021): e0251009. http://dx.doi.org/10.1371/journal.pone.0251009.

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Hydroxyapatite (HAp)—[Ca10 (PO4)6(OH) 2] has a similar chemical composition to bone material, making it the main mineral supplement in bone-making. Due to its high biocompatibility, hydroxyapatite is widely used in the repair of bone deficiencies and in the production of dental or orthopedic implants. In this research, hydroxyapatite nanopowder was synthesized using a hydrothermal technique. Fourier Transform Infrared Spectroscopy (FTIR) and transmission electron microscopy (TEM) were used to investigate the chemical structure and morphology of the synthesized hydroxyapatite powder. X-ray diffraction (XRD) was used to evaluate the phase analysis of HAp nanopowder. In addition, bioactivity HAp assessment was conducted by scanning electron microscopy (SEM) attached with Energy Dispersive X-Ray Spectroscopy (EDX) analysis. Response Surface Methodology (RSM) with central composite design (CCD) was used in order to determine the optimal conditions for yield, size, and crystallinity. Three independent variables (pH, temperature, and hydrothermal treatment time) were investigated. The yield was observed to increase in alkaline conditions; pH showed the greatest influence on the yield, size, and crystallinity of the synthesized hydroxyapatite, based on Analysis of Variance. The results of bioactivity evaluation are showed high bioactivity due to the formation of apatite on the surface of the synthesized nanopowder.

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Honary, Soheila, Hamed Barabadi, Pouneh Ebrahimi, Farzaneh Naghibi e Ahad Alizadeh. "Development and Optimization of Biometal Nanoparticles by Using Mathematical Methodology: A Microbial Approach". Journal of Nano Research 30 (marzo 2015): 106–15. http://dx.doi.org/10.4028/www.scientific.net/jnanor.30.106.

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This study aimed to biosynthesize and optimize the process of iron oxide nanoparticles producing by Penicilliumwaksmanii isolated from soil by employing mathematical methodology. The synthesized nanoparticles were formed with fairly well-defined dimensions with good monodispersity determined by SEM (Scanning Electron Microscopy), AFM (Atomic Force Microscopy), DLS (Dynamic Light Scattering), UV-Visible spectroscopy, zeta potential, polydispersity index (PDI) and correlogram of nanoparticles. The effects of different factors such as pH, temperature and concentration of FeCl3 on the particle size were investigated by Box-Behnken experimental design. The R2 value was calculated to be 0.9992 indicating the accuracy and ability of the polynomial model.

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Steven, Alasdair C. "Breakthroughs and breakdowns: the portrayal of biological macromolecules in computer-processed images of negatively stained specimens". Proceedings, annual meeting, Electron Microscopy Society of America 44 (agosto 1986): 62–65. http://dx.doi.org/10.1017/s0424820100142025.

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Negative staining - the contrast enhancement technique of applying solutions of heavy metal salts to macromolecular particles whose structures are ultimately inferred from the distribution of electron-opaque material that envelopes them - was introduced almost thirty years ago. Since then, the technique has undergone many modifications and refinements, but remains perhaps the most widely used method of preparing isolated biological macromolecules for electron microscopic observation. The advent of image processing, with its potentialities for noise reduction and three-dimensional reconstruction, greatly expanded the scope of negative staining electron microscopy for quantitative reproducible structural analyses. Here we survey the development of this combined methodology and consider its capabilities and limitations as currently practised.

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Faas, Frank G. A., M. Cristina Avramut, Bernard M. van den Berg, A. Mieke Mommaas, Abraham J. Koster e Raimond B. G. Ravelli. "Virtual nanoscopy: Generation of ultra-large high resolution electron microscopy maps". Journal of Cell Biology 198, n. 3 (6 agosto 2012): 457–69. http://dx.doi.org/10.1083/jcb.201201140.

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A key obstacle in uncovering the orchestration between molecular and cellular events is the vastly different length scales on which they occur. We describe here a methodology for ultrastructurally mapping regions of cells and tissue as large as 1 mm2 at nanometer resolution. Our approach employs standard transmission electron microscopy, rapid automated data collection, and stitching to create large virtual slides. It greatly facilitates correlative light-electron microscopy studies to relate structure and function and provides a genuine representation of ultrastructural events. The method is scalable as illustrated by slides up to 281 gigapixels in size. Here, we applied virtual nanoscopy in a correlative light-electron microscopy study to address the role of the endothelial glycocalyx in protein leakage over the glomerular filtration barrier, in an immunogold labeling study of internalization of oncolytic reovirus in human dendritic cells, in a cryo-electron microscopy study of intact vitrified mouse embryonic cells, and in an ultrastructural mapping of a complete zebrafish embryo slice.

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Wen, Haiming, Yaojun Lin, David N. Seidman, Julie M. Schoenung, Isabella J. van Rooyen e Enrique J. Lavernia. "An Efficient and Cost-Effective Method for Preparing Transmission Electron Microscopy Samples from Powders". Microscopy and Microanalysis 21, n. 5 (9 settembre 2015): 1184–94. http://dx.doi.org/10.1017/s1431927615014695.

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AbstractThe preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpled discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.

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Paterson, Gary W., Gavin M. Macauley, Stephen McVitie e Yoshihiko Togawa. "Parallel Mode Differential Phase Contrast in Transmission Electron Microscopy, I: Theory and Analysis". Microscopy and Microanalysis 27, n. 5 (20 settembre 2021): 1113–22. http://dx.doi.org/10.1017/s1431927621012551.

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In Part I of this diptych, we outline the parallel mode of differential phase contrast (TEM-DPC), which uses real-space distortion of Fresnel images arising from electrostatic or magnetostatic fields to quantify the phase gradient of samples with some degree of structural contrast. We present an analysis methodology and the associated software tools for the TEM-DPC method and, using them together with numerical simulations, compare the technique to the widely used method of phase recovery based on the transport-of-intensity equation (TIE), thereby highlighting the relative advantages and limitations of each. The TEM-DPC technique is particularly suitable for in situ studies of samples with significant structural contrast and, as such, complements the TIE method since structural contrast usually hinders the latter, but is an essential feature that enables the former. In Part II of this work, we apply the theory and methodology presented to the analysis of experimental data to gain insight into two-dimensional magnetic phase transitions.

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Huh, PilHo, e Seong-Cheol Kim. "Nanostructured ZnO Arrays with Self-ZnO Layer Created Using Simple Electrostatic Layer-by-Layer Assembly". Journal of Nanomaterials 2012 (2012): 1–6. http://dx.doi.org/10.1155/2012/131672.

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Formation of unique ZnO nanoarrays utilizing photodynamic polymer, surface-relief grating structures, and unique electrostatic layer-by-layer assembly as a simple and economical methodology was demonstrated. Atomic force microscope (AFM), scanning electron microscopy (SEM), and energy-dispersive X-ray (EDAX) analysis were employed to characterize elemental composition and morphology of the resulting ZnO nanostructures with self-ZnO layer. Optical behavior of the final product was studied by UV-vis-NIR absorption and photoluminescence (PL) spectra.

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Karimi Sabet, Javad, Cyrus Ghotbi e Farid Dorkoosh. "Application of Response Surface Methodology for Optimization of Paracetamol Particles Formation by RESS Method". Journal of Nanomaterials 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/340379.

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Ultrafine particles of paracetamol were produced by Rapid Expansion of Supercritical Solution (RESS). The experiments were conducted to investigate the effects of extraction temperature (313–353 K), extraction pressure (10–18 MPa), preexpansion temperature (363–403 K), and postexpansion temperature (273–323 K) on particles size and morphology of paracetamol particles. The characterization of the particles was determined by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Liquid Chromatography/Mass Spectrometry (LC-MS) analysis. The average particle size of the original paracetamol was 20.8 μm, while the average particle size of paracetamol after nanonization via the RESS process was 0.46 μm depending on the experimental conditions used. Moreover, the morphology of the processed particles changed to spherical and regular while the virgin particles of paracetamol were needle-shape and irregular. Response surface methodology (RSM) was used to optimize the process parameters. The extraction temperature, 347 K; extraction pressure, 12 MPa; preexpansion temperature, 403 K; and postexpansion temperature, 322 K was found to be the optimum conditions to achieve the minimum average particle size of paracetamol.

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Batuk, Dmitry, Maria Batuk, Artem M. Abakumov e Joke Hadermann. "Synergy between transmission electron microscopy and powder diffraction: application to modulated structures". Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 71, n. 2 (31 marzo 2015): 127–43. http://dx.doi.org/10.1107/s2052520615005466.

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The crystal structure solution of modulated compounds is often very challenging, even using the well established methodology of single-crystal X-ray crystallography. This task becomes even more difficult for materials that cannot be prepared in a single-crystal form, so that only polycrystalline powders are available. This paper illustrates that the combined application of transmission electron microscopy (TEM) and powder diffraction is a possible solution to the problem. Using examples of anion-deficient perovskites modulated by periodic crystallographic shear planes, it is demonstrated what kind of local structural information can be obtained using various TEM techniques and how this information can be implemented in the crystal structure refinement against the powder diffraction data. The following TEM methods are discussed: electron diffraction (selected area electron diffraction, precession electron diffraction), imaging (conventional high-resolution TEM imaging, high-angle annular dark-field and annular bright-field scanning transmission electron microscopy) and state-of-the-art spectroscopic techniques (atomic resolution mapping using energy-dispersive X-ray analysis and electron energy loss spectroscopy).

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GAJDARDZISKA-JOSIFOVSKA, M., M. H. MALAY e DAVID J. SMITH. "REFLECTION ELECTRON MICROSCOPY METHODOLOGY FOR QUANTIFICATION OF CLUSTER GROWTH: INDIUM CLUSTERS ON THE InP(110) SURFACE". Surface Review and Letters 04, n. 04 (agosto 1997): 655–69. http://dx.doi.org/10.1142/s0218625x97000651.

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Dynamical reflection electron microscopy (REM) can provide a wealth of time-resolved data pertinent to the initial and intermediate stages of cluster growth. REM allows one to follow and quantify the size and shape evolution of individual clusters. Average cluster size and cluster density data can be obtained as a function of time due to the large field of view produced by REM image foreshortening. We describe here a methodology for extracting these data from dynamical REM experiments, based on a geometrical model for the interpretation of REM images from two- and three-dimensional clusters. This methodology has been applied to studies of In cluster growth on InP (110) surfaces at 650°C. The average In cluster height and length initially increased as a fourth root of time, with a constant contact angle with the surface, consistent with surface-diffusion-limited growth of 3D clusters. The same behavior was found in the later stage of cluster growth, but the intermediate stage showed anomalous power laws for the cluster height and base length, accompanied by a decrease in the contact angle between the In clusters and the InP (110) surface. This anomalous regime can be explained by growth of In clusters into the InP substrate, when the true contact angle is no longer defined with respect to the InP(110) surface.

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Lin, Wan-Hsien, Uwe Jahn, Hanno Küpers, Esperanza Luna, Ryan B. Lewis, Lutz Geelhaar e Oliver Brandt. "Efficient methodology to correlate structural with optical properties of GaAs nanowires based on scanning electron microscopy". Nanotechnology 28, n. 41 (13 settembre 2017): 415703. http://dx.doi.org/10.1088/1361-6528/aa8394.

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