Standard Scanning Electron Microscopy Research Articles

#2281 SEM for the diagnosis of glomerular diseases (amyloidosis, minimal change, thin membrane, IgA, membranoproliferative and diabetic nephropathy)

Abstract Background and Aims Treating renal diseases often requires ultrastructural details to establish or confirm diagnosis. Ultrastructural information that is not evidenced by optical microscopy includes, e.g., the podocyte foot processes effacement, thinning or alteration of basement membrane, presence of fibrils, Fabri's intracellular inclusions and subepithelial vs. subendothelial of deposits. Unfortunately, transmission electron microscopy (TEM), required to achieve the required resolution, has high costs, and is time-consuming. Here, we report our experience with scanning electron microscopy (SEM) on paraffin sections from standard pathology sections. Method We have retrospectively reanalyzed paraffin sections from renal biopsies of 50 patients with a diagnosis of IgAN, minimal change, diabetes, and amyloidosis. The paraffin sections were available and processed according to standard procedures (fixation, paraffin embedding), with a thickness of 3-4 µm. Sections were deparaffinized, stained with PASM (periodic acid Shiff + methenamine), mounted in aqueous mounting medium and imaged with 40x and 60x objectives. Sections were then unmounted, washed to remove glycerol, dehydrated in absolute alcohol, and air-dried. Finally, they were gold coated (“sputtering”) and analyzed in a scanning electron microscope (Zeiss). Results For the interpretation of SEM images, correlative analysis has been used, imaging precisely the same region of the section using standard optical microscopy and SEM. SEM can quickly identify the typical morphology of podocyte foot processes (Fig. 1A) and the podocyte effacement in minimal change disease (Fig. 1B). SEM can also easily allow the measurement of the thickness of the basement membrane of glomerular capillary walls (Fig. 1C-E) and its thinning in case of thin membrane disease (Fig. 1D) or its increased thickness in the case of diabetes (Fig. 1E). Amyloid fibrils (Fig. 1F) can also be identified in the capillary walls, confirming the diagnosis of amyloidosis Congo-red positive (Fig. 1G). The high resolution of the technique allows us to identify with high reliability the small ruptures of the capillary walls in IgA and membranoproliferative nephritis, with extravasation of erythrocytes and fibrin cloths (Fig. 1H). Mitochondria are well-demarcated, particularly in proximal tubule cells, and often, mitochondrial cristae are visible in samples with adequate fixation (Fig. 1I). Interstitial edema and fibrosis are evident in SEM microscopy (Fig. 1L). At very high magnification, in histological preparations with exceptional fixation, the filtration pores of endothelial cells could be observed (partially visible in Fig. 1E), as well as details such as the brush border of the tubular epithelial cells. The interpretation of the images is not always straightforward as it also requires knowledge of the artifacts induced by the fixation, processing, and inclusion of paraffin, such as, for example, the intracytoplasmic cellular structures containing lipids of the intratubular “foam cells” appear empty. For a correct interpretation of the SEM images, however, the recognition of the nuclei is essential because the chromatin is condensed into clods, especially around the periphery, and inside, some areas appear empty. Conclusion Scanning electron microscopy (SEM) is a powerful tool for the study of nephrological diseases, as it allows you to examine microscopic details at the nanometric scale (not detectable in optical microscopy), providing valuable information for diagnosis, understanding, and management of the disease, the possibility of carrying out Correlative Microscopy. Given the relatively simple and fast preparation of the samples to be examined, the low costs of execution, and the possibility of archiving the preparation in the histotheque for a possible revision of the case, this leads us to think that this method could be considered a valid alternative to transmission electron microscopy (TEM).

Scanning Electron Microscopy.

Scanning electron microscopy (SEM) remains distinct in its ability to allow topographical visualization of structures. Key elements to consider for successful examination of biological specimens include appropriate preparative and imaging techniques. Chemical processing induces structural artifacts during specimen preparation, and several factors need to be considered when selecting fixation protocols to reduce these effects while retaining structures of interest. Particular care for proper dehydration of specimens is essential to minimize shrinkage and is necessary for placement under the high-vacuum environment required for routine operation of standard SEMs. Choice of substrate for mounting and coating specimens can reduce artifacts known as charging, and a basic understanding of microscope settings can optimize parameters to achieve desired results. This article describes fundamental techniques and tips for routine specimen preparation for a variety of biological specimens, preservation of labile or fragile structures, immune-labeling strategies, and microscope imaging parameters for optimal examination by SEM. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Chemical preparative techniques for preservation of biological specimens for examination by SEM Alternate Protocol 1: Practical considerations for the preparation of soft tissues Alternate Protocol 2: Removal of debris from the exoskeleton of invertebrates Alternate Protocol 3: Fixation of colonies grown on agar plates Alternate Protocol 4: Stabilization of polysaccharide structures with alcian blue and lysine Alternate Protocol 5: Preparation of non-adherent particulates in solution for SEM Support Protocol 1: Application of thin layer of adhesive on substrate to improve adherence Support Protocol 2: Poly-L-lysine coating specimen substrates for improved adherence Support Protocol 3: Microwave processing of biological specimens for examination by SEM Basic Protocol 2: Critical point drying of specimens Alternate Protocol 6: Chemical alternative to critical point drying Basic Protocol 3: Sputter coating Alternate Protocol 7: Improved bulk conductivity through "OTOTO" Basic Protocol 4: Immune-labeling strategies Alternate Protocol 8: Immune-labeling internal antigens with small gold probes Alternate protocol 9: Quantum dot or fluoronanogold preparations for correlative techniques Basic Protocol 5: Exposure of internal structures by mechanical fracturing Basic Protocol 6: Exposure of internal structures of tissues by fracturing with liquid nitrogen Basic Protocol 7: Anaglyph production from stereo pairs to produce 3D images.

A piezoelectric-driven nanoindentation system for scanning electron microscope with improved analog compensation method.

This paper presents a novel piezoelectric-driven nanoindentation system for a scanning electron microscope (SEM) with an improved analog compensation (IAC) method. This system mainly consists of a piezoelectric-driven indenter head, a rectangle-shaped transducer, and a nanopositioner module. Compared with the state-of-the-art piezoelectric-driven nanoindentation system with a circle-shaped transducer, the proposed nanoindentation system is capable of multi-direction operation inside a SEM with a rectangle-shaped transducer. Self-matched semiconductor strain gauges are selected as the position sensor for the piezoelectric-actuator. The Wheatstone bridge output voltage cannot achieve a zero temperature coefficient because the temperature coefficients of self-matched semiconductor strain gauge pairs become significantly different from each other after installation in practice. An IAC method is proposed to compensate the temperature coefficients further. Compared with the existing analog compensation method, the IAC method solves the problem of amplifier saturation and improves the sensitivity of the self-matched semiconductor strain gauge pairs position sensor by 27%. The multi-direction operation results inside a standard SEM HITACHI SU5000 validate the advantage of the developed nanoindentation system.

Fracture Patterns of Rocks Observed under Cryogenic Conditions Using Cryo-Scanning Electron Microscopy

Cryogenic fracturing, which uses liquid nitrogen (LN2) as a fracturing fluid, is a waterless fracturing method. However, previous attempts to investigate the fracture morphology of rocks after LN2 quenching have been mainly based on standard scanning electron microscopy (SEM) analysis at room temperature. This can be problematic since thermally-induced fractures created by temperature difference tend to close as a sample warms and thermal stress relaxes. To address this issue, we established a novel approach employing Cryo-scanning electron microscopy (Cryo-SEM) to investigate the fracture patterns induced by liquid nitrogen quenching under cryogenic conditions. This method can achieve in-situ visualization of fractures and pores with a nano-scale resolution at −190 °C. X-ray computed tomography (CT) is also employed to illustrate the fracture distribution inside samples. Cryo-SEM and standard SEM are compared, and statistical assessments are conducted to quantify fracture aperture size and closure scale. The results demonstrate that Cryo-SEM can more accurately preserve native fracture morphology and provide a more accurate means of evaluating fracture scales generated during LN2 quenching, particularly at higher temperature differences between rock and liquid nitrogen. Distinct fracture patterns and fracture width are observed for various rock types (i.e., coal, sandstone, shale, granite) by using these methods. More prominently, the maximum fracture width of coal, sandstone, shale and granite were 89.17 µm, 1.29 µm, 0.028 µm and 2.12 µm when the temperature difference between LN2 and rock samples were 296 °C. LN2 is shown to exhibit superior fracturing efficiency on coal and granite, characterized by complex fracture networks with branched fractures. This research contributes to our understanding of liquid nitrogen fracturing mechanisms and may offer effective approaches for unconventional reservoirs stimulation.

Computer Vision Applied to In-Situ Specimen Orientation Adjustment for Quantitative SEM Analysis

Abstract Quantitative analysis methods based on the usage of a scanning electron microscope (SEM), such as energy-dispersive X-ray spectroscopy, often require specimens to have a flat surface oriented normal to the electron beam. In-situ procedures for putting microscopic flat surfaces into this orientation generally rely on stereoscopic methods that measure the change in surface vector projections when the surface is tilted by some known angle. Although these methods have been used in the past, there is no detailed statistical analysis of the uncertainties involved in such methods, which leaves an uncertainty in how precisely a specimen can be oriented. Here, we present a first principles derivation of a specimen orientation method and apply our method to a flat sample to demonstrate it. Unlike previous works, we develop a computer vision program using the scale-invariant feature transform to automate and expedite the process of making measurements on our SEM images, thus enabling a detailed statistical analysis of the method with a large sample size. We find that our specimen orientation method is able to orient flat surfaces with high precision and can further provide insight into errors involved in the standard SEM rotation and tilt operations.

Study on the temperature effect on line-scan profile of nanorods under electron irradiation

Scanning electron microscope (SEM) is widely used in imaging rather than for thermometry. In this work, the temperature-dependent line-scan profiles for two systems (one gold (Au) nanorod (Au-NR) and one silicon (Si) nanorod (Si-NR) on Si substrate, respectively) were investigated by a simulation approach. Various electron signals (secondary electron (SE) and backscattering electron (BSE)) were recorded with different values of temperature at various primary electron (PE) energies. It is found that the SE line-scan profile varies with the temperature and the size of the NR. However, the BSE line-scan profile is almost unchanged with temperature for the Au/Si system, but remarkably varied for the Si/Si system. The deposited energies contributed by full electrons, PEs and cascaded electrons as functions of depth and radial direction at different temperatures for these two systems were also investigated. It was concluded that the influences of the temperature of a solid on the scattering processes of PEs and cascaded electrons are different. Possible mechanisms were systematically analyzed based on the theory of electron-solid interaction. Finally, the temperature effect on the size measurement based on a line-scan profile was also investigated through the regression to baseline method. It was found that the broaden value slightly increases with temperature. This work poses a potential possibility of measuring the temperature of nanostructures by acquiring the temperature-dependent line-scan profile by a standard SEM.

Highly Sensitive and Quantitative Diagnosis of SARS-CoV-2 Using a Gold/Platinum Particle-Based Lateral Flow Assay and a Desktop Scanning Electron Microscope.

The gold standard test for identifying SARS-CoV-2, the causative agent of COVID-19, is polymerase chain reaction (PCR). Despite their limited sensitivity, SARS-CoV-2 antigen rapid diagnostic tests are vital tools in the fight against viral spread. Owing to its simplicity and low cost, the lateral flow assay (LFA) is the most extensively used point-of-care diagnostic test. Here, we report a newly designed LFA-NanoSuit method (LNSM) that works in conjunction with desktop scanning electron microscopy (SEM) to detect SARS-CoV-2. LNSM requires no standard SEM treatment, avoids cellulose and residual buffer deformation, and enables the capture of high-resolution images of antibody-labeled gold/platinum particles reacting with SARS-CoV-2 antigens. To assess its applicability, we compared clinical SARS-CoV-2 samples via visual detection of LFA, LSNM detection of LFA, and real-time reverse transcription-PCR (qRT-PCR). Compared to qRT-PCR, LNSM showed 86.7% sensitivity (26/30; 95% confidence interval (CI): 69.28–96.24%) and 93.3% specificity (14/15; 95% CI: 68.05–99.83%) for SARS-CoV-2. In samples with a relatively low SARS-CoV-2 RNA copy number (30 < Ct ≤ 40), the sensitivity of LNSM was greater (73.3%) than that of visual detection (0%). A simple, sensitive, and quantitative LNSM can be used to diagnose SARS-CoV-2.

Small grains as recombination hot spots in perovskite solar cells

Summary Non-radiative recombination in the perovskite bulk and at its interfaces prohibits the photovoltaic performance from reaching the Shockley-Queisser limit. While interfacial recombination has been widely discussed and demonstrated, bulk recombination and especially the influence of grain boundaries remain under debate. Most studies explore the role of grain boundaries on perovskite films rather than devices, making it difficult to link the film properties with those of the devices. Here, we systematically investigate the effects of grain boundaries on the performance of perovskite solar cells by two different methods. By combining experimental characterization with theoretical device simulations, we find that the recombination at grain boundaries is diffusion limited and hence is inversely proportional to the grain area to the power of 3/2. Consequently, the prevalence of small grains—which act as recombination hot spots—across the perovskite active layer dictates the photovoltaic performance of the perovskite solar cells.

Retrieving dissolved H2O content from micro-Raman spectroscopy on nanolitized silicic glasses: Application to volcanic products of the Paraná Magmatic Province, Brazil

Determining volatile content in silicate glasses has critical importance to evaluate the original water content of magmas and its evolution from storage to eruption. Here we present a Raman spectroscopic study devoted to defining an optimized analytical procedure for the determination of dissolved water content of nano-crystallized ancient silicic glasses, belonging to the Paraná Magmatic Province (PMP) volcanism in South Brazil (131 to 134 Ma). A set of anhydrous glasses was prepared under atmospheric pressure by melting and quenching of natural rocks. These glasses were later hydrated under high pressure in an Internally Heated Pressure Vessel (IHPV). Even after rapid quenching, most of the dry and hydrous glasses showed prominent Raman peaks at ca. 670–690 cm−1, which are associated with the presence of Ti-magnetite nanolites. Although large Raman peaks are observed, the nanolites are invisible to standard Scanning Electron Microscopy (SEM) due to their small size and not quantifiable by X-ray diffraction (XRD) because of their low abundance. Available models and procedures to estimate water content in glasses are calibrated with crystal-free glasses and were proved inadequate for water measurement in nanolite-bearing glasses. Here we provide new calibration strategies to determine the water content in nanolite-bearing glasses. These strategies are based on the normalization of the intensity and area of the water band (3550 cm−1) to the individual vibrational bands of the silicate framework of the glass, at 350–500 cm−1 and 860–1240 cm−1. Our new calibrations were used to estimate the dissolved water content of glass matrixes of natural dacitic vitrophyres from the Caxias do Sul volcanic suite, whose Raman spectra show nanolite peaks of variable intensity. Our work constitutes a further step ahead toward the definition of strategies to determine the volatile content in natural multicomponent and multiphase glasses.

Tracking endocytosis and intracellular distribution of spherical nucleic acids with correlative single-cell imaging.

A comprehensive understanding of interactions between nanoparticles (NPs) and biological components is critical to the clinical application of NPs and nanomedicine. Here we provide a step-by-step correlative imaging approach to investigate plasmonic NPs of different aggregation states at the single-cell level. Traceable spherical nucleic acids (SNAs) are fabricated by decorating 50-nm spherical gold NPs with fluorophore-labeled DNA, serving as dually emissive (fluorescent and plasmonic) NPs. The in situ correlative imaging with dark-field microscopy (DFM) and fluorescence microscopy (FM) reveals intracellular distribution of SNAs, whereas DFM combined with scanning electron microscopy (SEM) allows semi-quantification of SNA clustering states in solution. The imaging data are analyzed by ImageJ and a colorimetry-based algorithm written in Python. The clustering states of SNAs in a single cell can be efficiently distinguished within 20 s. This method can be readily installed to monitor real-time endocytosis and cellular distribution of plasmonic NPs of different aggregation states and to quantitatively image targets of interest (e.g., specific DNA, messenger RNA, peptides or proteins) in living cells. The entire procedure can be completed in 3-5 d and requires standard DFM, FM and SEM imaging and data analysis skills and equipment.

Silica bodies of Selaginella erythropus: Detection, morphology and development

Selaginellaceae (Lycopodiophyta), an early divergent group of vascular plants, are a species-rich and taxonomically challenging family. Here we study silica bodies on the leaves of a prominently studied Selaginella, S. erythropus, with various methods of microscopy and energy disperse X-ray analysis (EDX) to characterize their properties in mature and emerging leaves.To detect silica bodies, a light microscope or a fluorescence microscope can be used to reveal colorless silica body protrusions in the epidermal cell walls. Silica bodies show as light spots with scanning electron microscopy (SEM). However, the recent tabletop SEM featured with low accelerating voltage and backscattered electron detectors provides a better contrast than standard SEM. EDX shows that these protrusions on leaf surfaces are silica bodies and that trichome apices and some stomata also have silica deposits. Atomic force microscopy provides three-dimensional images and quantitative measurements, but with an upper limit on silica body size. Under transmission electron microscopy silica bodies are characterized as compact electron-dense particles, gradually thinning and mingling with the cell wall.These analyses recognized two major forms of silica bodies, conical (small and large subforms) and sinuate-carinate. Distinct forms are found on different types of epidermal cells. Patterns on a leaf surface differ between the four types of leaf surface, dorsal and ventral surfaces of dorsal and ventral leaves, and may have taxonomic value.The silicification process on a young leaf begins from the central part. Large conical silica bodies appear first, along leaf margins and trichomes. Then, small conical silica bodies develop. Sinuate-carinate forms arise from the merger of large conical forms.A full understanding of the functional significance of silica bodies in Selaginella has yet to be developed, but we hope this report can help researchers detect silica bodies, and inspire more studies.

GaN nanowires as probes for high resolution atomic force and scanning tunneling microscopy

GaN nanowires are potential candidates for use in scanning probe microscopy due to their well-defined, reproducible, geometric shapes, their hardness, and their light guiding properties. We have developed and investigated probes for high resolution atomic force microscopy and scanning tunneling microscopy utilizing GaN nanowires as probes. The nanowires are n-doped and the morphology of the nanowires has been tailored for scanning probe microscopy by growing them with a sharp tip for measurements and high thickness for robustness. The individual GaN nanowires were removed from their growth substrate and attached onto commercial atomic force microscopy cantilevers or etched tungsten wires for scanning tunneling microscopy. A standard scanning electron microscope equipped with a nanoprobe, a focused ion beam column and a gas injection system was used to locate, transfer, and attach the nanowires. We evaluated the properties of the GaN probes on different substrates including HOPG, Au, SiO2, InAs, and GaAs. We demonstrate both atomic force microscopy and scanning tunneling microscopy measurements with single atomic layer resolution and evaluate the robustness of the tips by monitoring them before and after scanning. Finally, we explore the use of the tips for scanning tunneling spectroscopy demonstrating that reliable results, which can reveal information on the electronic properties of the surface-tip system, are obtainable. The fundamental properties of these probes, which are demonstrated in this work, show promise for future use of the probes in exploring semiconductor-semiconductor tunneling junctions at the nanoscale as well as for other scanning probe techniques where high resolution is required.

Correction of parasitic aberrations of hexapole corrector using differential algebra method

We demonstrate an application of the differential algebraic method in optimization of a hexapole corrector of spherical aberration for the transmission regime of the standard scanning electron microscope. We introduce the method by visualization of the effect of all correcting elements to illustrate the principle of the corrector. Special interest is given to parasitic aberrations and their correction using additional deflectors before and inside the corrector. They can alter the off-axial position and tilt of the beam in the hexapoles. The critical values of the parasitic aberration coefficients are calculated using a wave-optical method, which determines the stability of the deflection system, the lens doublet, and the hexapoles. The derived properties of the parasitic aberrations are used in an alignment procedure of the system with the corrector.

Fabrication of Polyimide Optical Waveguide on Silicon Dioxide Layer Stacked Silicon Substrate

Optical waveguides are important for guiding lightwave from a place to other places. Propagation and insertion losses of the optical waveguides should be considered to be in low values. Recently, optical waveguides with circular structures, which are optical fibers, are used widely for guiding lightwave in long-distance optical communication with very low propagation and insertion losses. Simultaneously, optical waveguides with planar structure are also developed for short distance communication in optical devices. We have reported design and analysis of the planar optical waveguides. In this paper, fabrication of planar optical waveguides using a polyimide material on thin silicon dioxide combined with the silicon substrate is reported. The polyimide material is used for the core of the optical waveguides. The silicon dioxide located on the silicon substrate and the air is used for cladding of the optical waveguides. Fabrication of the optical waveguides such as oxidation, photoresist coating, masking, ultra-violet exposure, and etching was done. The fabricated optical waveguides were characterized physically using a standard microscope and scanning electron microscope (SEM). The fabrication processes and characterization results are reported and discussed in detail.

Binder and SEI Distribution on the Negative Electrode of Lithium-Ion Batteries

The structure and distribution of the polymeric binders in lithium-ion battery (LIB) electrodes as well as those of the solid-electrolyte-interface (SEI) play an important role for the performance and lifetime of a LIB. While in particular the SEI has been intensively studied by spectroscopic methods, first and foremost by x-ray photoelectron spectroscopy (XPS), little is known about its local distribution and potential structural inhomogeneities due to the lack of spatial resolution of these methods. Both the binder as well as the SEI form structures which are typically just a few nanometer in thickness and are therefore not accessible to light microscopy or even standard scanning electron microscopy (SEM). While high resolution SEM (HR-SEM) or transmission electron microscopy may in principle be able to resolve SEI or binder structures, their investigation by electron microscopy is far from straight forward. This is to one part due to their composition. As electrode binders typically polymers like PVDF or CMC/SBR are used while the SEI consists of a mixture of inorganic salts of low z-elements like LiF, LiCO3 or LiOH and organic lithium salts. The low electron density of these materials in combination with a mostly amorphous structure makes detection and distinction highly challenging. This is even further complicated on the negative electrode side, because it mainly consists of carbonaceous materials, and therefore posses a very similar scattering contrast. Further, spectroscopic methods available to electron microscopy cannot easily detect lithium and carbon and oxygen are part of the carbonaceous host matrix and therefore not suitable for distinction. Another issue when studying the SEI by electron microcopy is its high sensitivity to beam induced radiation damage. While the energy dispersive x-ray (EDX) signal of fluorine may be used to detect gradients in the binder distribution for polyvinylendifluoride (PVDF) of a fresh electrode it falls short in resolving local binder structures due to the large scattering volume contributing to the EDX signal which limits resolution. For the SEI, which also contains fluorine in form of LiF, EDX is even less applicable, since the fluorine signal of LiF cannot be discriminated from that of the PVDF binder. Therefore, despite a rather similar initial problem, different approaches need to be followed to investigate binder and SEI structures by electron microscopy. In order to study the SEI layer we used the reactivity of some of its components towards osmium tetroxide fumes (OsO4). OsO4 is a strong oxidising agent and may therefore react with parts of the SEI layer. The osmium compounds formed significantly increase the local scattering contrast. The contrasting and fixation properties of OsO4 has beneficially been used for preparing biological tissues for electron microscopy. However, its application in material science is scarce. In this contribution we demonstrate how OsO4 can beneficially be used to study the SEI layer by electron microscopy. Further, we will shed some light on how OsO4 reacts with parts of the SEI and how the selective reaction of OsO4 may be used to improve our understanding of its structure. For the binder distribution a different approach was chosen. Energy selective imaging of backscattered electrons (ESB) is a rather new electron microscopy technique. Under certain conditions it may help to increase the contrast in samples with weak elemental contrast at a certain combination of acceleration voltage and filter grid voltage. Further, the low energy of the ESB electrons make it a very local probe with high lateral resolution. We were able to identify appropriate imaging conditions to clearly distinguish PVDF binder structures on carbon electrodes. The technique was applied to study the influence of the drying process on the binder distribution and new insights in how the drying process influences the distribution of binder and carbon black inside the electrode layer could be obtained.

Manufacturing and characterization of molybdenum pellets used as targets for 99mTc production in cyclotron

The method of 100Mo metallic target preparation for production of 99mTc by proton irradiation in 100Mo(p,2n)99mTc reaction was demonstrated. For this purpose, pressing of molybdenum powder into pellets and their subsequent sintering in reductive atmosphere were applied. The influence of parameters such as molybdenum mass and time of both pressing and sintering on the 100Mo target durability was investigated. Under the optimized conditions, 100Mo metallic pellet targets with density of 9.95±0.06g/cm3 were obtained. Morphology and structure of pressed pellets before and after sintering were studied by using standard optical microscope and Scanning Electron Microscope (SEM). Nanoindentation technique was used to investigate the mechanical properties such as nanohardness and Young modulus. Prepared 100Mo pellets were successfully irradiated with protons and 99mTc was efficiently isolated.

Natural Pineapple Leaf Fibre Extraction On Josapine And Morris

The pineapple’s leaf plant contains approximately 2.5% to 3.5% of strong white silky fibres. These fibres are useful and can be extracted from the leaves. There are a few ways to extract the fibre such as hand scrapping and by extraction machine. The objective of this research is to study the quality of fibre extraction by using different age of pineapple leaf. Next, the study aims to compare the quality of Josapine and Morris pineapple leaf with tensile test. Fibre yield percentage are calculated to determine which type of pineapple leaf produce high production of dry fibre. The mechanical properties of the fibres are analysed by Tensile Test under American Standard Testing Methods (ASTM C1577-03) and Scanning Electron Microscope (SEM). The result of the fibre yield percentage show the Josapine type on 12 month ages are the highest value fibre yield percentage which is 7.89%. Based on fibre yield percentages, it showed the Josapine type produce better dry fibre production compare to Morris type. Based on mechanical test, it showed Josapine type on 12 months ages are the strongest fibre compare to Morris type since it can withstand on 67.6 N of load.

AxonSeg: Open Source Software for Axon and Myelin Segmentation and Morphometric Analysis.

Segmenting axon and myelin from microscopic images is relevant for studying the peripheral and central nervous system and for validating new MRI techniques that aim at quantifying tissue microstructure. While several software packages have been proposed, their interface is sometimes limited and/or they are designed to work with a specific modality (e.g., scanning electron microscopy (SEM) only). Here we introduce AxonSeg, which allows to perform automatic axon and myelin segmentation on histology images, and to extract relevant morphometric information, such as axon diameter distribution, axon density and the myelin g-ratio. AxonSeg includes a simple and intuitive MATLAB-based graphical user interface (GUI) and can easily be adapted to a variety of imaging modalities. The main steps of AxonSeg consist of: (i) image pre-processing; (ii) pre-segmentation of axons over a cropped image and discriminant analysis (DA) to select the best parameters based on axon shape and intensity information; (iii) automatic axon and myelin segmentation over the full image; and (iv) atlas-based statistics to extract morphometric information. Segmentation results from standard optical microscopy (OM), SEM and coherent anti-Stokes Raman scattering (CARS) microscopy are presented, along with validation against manual segmentations. Being fully-automatic after a quick manual intervention on a cropped image, we believe AxonSeg will be useful to researchers interested in large throughput histology. AxonSeg is open source and freely available at: https://github.com/neuropoly/axonseg.

Lock-in thermography, penetrant inspection, and scanning electron microscopy for quantitative evaluation of open micro-cracks at the tooth–restoration interface

The evaluation of a dental restoration in a non-invasive way is of paramount importance in clinical practice. The aim of this study was to assess the minimum detectable open crack at the cavity–restorative material interface by the lock-in thermography technique, at laser intensities which are safe for living teeth. For the analysis of the interface, 18 box-type class V standardized cavities were prepared on the facial and oral surfaces of each tooth, with coronal margins in enamel and apical margins in dentine. The preparations were restored with the Giomer Beautifil (Shofu) in combination with three different adhesive systems. Three specimens were randomly selected from each experimental group and each slice has been analysed by visible, infrared (IR), and scanning electron microscopy (SEM). Lock-in thermography showed the most promising results in detecting both marginal and internal defects. The proposed procedure leads to a diagnosis of micro-leakages having openings of 1 µm, which is close to the diffraction limit of the IR camera. Clinical use of a thermographic camera in assessing the marginal integrity of a restoration becomes possible. The method overcomes some drawbacks of standard SEM or dye penetration testing. The results support the use of an IR camera in dentistry, for the diagnosis of micro-gaps at bio-interfaces.

An optimized methodology to analyze biopolymer capsules by environmental scanning electron microscopy.

The aim of this paper is to describe an optimized methodology to study the surface characteristics and internal structure of biopolymer capsules using scanning electron microscopy (SEM) in environmental mode. The main advantage of this methodology is that no preparation is required and, significantly, no metallic coverage is deposited on the surface of the specimen, thus preserving the original capsule shape and its surface morphology. This avoids introducing preparation artefacts which could modify the capsule surface and mask information concerning important feature like porosities or roughness. Using this method gelatin and mainly fatty coatings, difficult to be analyzed by standard SEM technique, unambiguously show fine details of their surface morphology without damage. Furthermore, chemical contrast is preserved in backscattered electron images of unprepared samples, allowing visualizing the internal organization of the capsule, the quality of the envelope, etc... This study provides pointers on how to obtain optimal conditions for the analysis of biological or sensitive material, as this is not always studied using appropriate techniques. A reliable evaluation of the parameters used in capsule elaboration for research and industrial applications, as well as that of capsule functionality is provided by this methodology, which is essential for the technological progress in this domain.