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Micron

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https://read.qxmd.com/read/30953869/inhibition-of-autophagy-impairs-acrosome-and-mitochondrial-crista-formation-during-spermiogenesis-in-turtle-ultrastructural-evidence
#1
Abdul Haseeb, Imran Tarique, Xuebing Bai, Ping Yang, Waseem Ali Vistro, Yufei Huang, Sarfaraz Ali Fazllani, Zulfqur Ahmed, Qiusheng Chen
Autophagy is a subcellular process that is extensively involved in spermiogenesis. In this study, we observed ultrastructural malformation of acrosome and mitochondrial cristae during the spermiogenesis of Chinese soft-shelled turtle due to the inhibition of autophagy. Autophagy was blocked with 3-MA, and the inhibition of autophagy was confirmed through western blot analysis. The morphological abnormalities of acrosomes and mitochondria were observed under transmission electron microscopy (TEM). In the early spermiogenesis (Golgi and cap phases), damaged macrovesicle was observed, and its proper expansion over the nucleus failed to be form a normal acrosomal cap...
April 1, 2019: Micron
https://read.qxmd.com/read/30981155/an-imagej-tool-for-simplified-post-treatment-of-tem-phase-contrast-images-spci
#2
Verguet Amandine, Messaoudi Cédric, Marco Sergio, Donnadieu Patricia
Tools for taking advantage of phase-contrast in transmission electron microscopy are of great interest for both biological and material sciences studies as shown by the recent use of phase plates and the development of holography. Nevertheless, these tools most often require highly qualified experts and access to advanced equipment that can only be considered after preliminary investigations. Here we propose to address this issue by the development of an ImageJ plugin that allow the retrieval of a phase image by simple numerical treatment applied to two defocused images...
March 28, 2019: Micron
https://read.qxmd.com/read/30951928/monitoring-bioturbation-by-a-small-marine-polychaete-using-microcomputed-tomography
#3
Simone Pennafirme, Alessandra S Machado, Alessandra C Machado, Ricardo T Lopes, Inaya C B Lima, Mirian A C Crapez
Bioturbation is one of the principle biological processes involved in transporting particles and solutes within sediments, which contributes to the maintenance of biodiversity. In muddy polluted environments, bioturbation may increase pollutant flux at the water-sediment interface, thereby enhancing contaminant bioavailability. The behavior of organisms dictates bioturbation, and gallery shape influences the magnitude of solute transport. Thus, quantitative investigations of gallery shape are fundamental to understanding how pollutant and solute transport is enhanced by bioturbators in muddy sediments...
March 26, 2019: Micron
https://read.qxmd.com/read/30947035/fluctuations-in-cell-cycle-morphology-and-metabolism-of-anemia-phyllitidis-gametophytes-are-the-most-important-hallmarks-of-ga-3-induced-antheridiogenesis
#4
Andrzej Kaźmierczak
The research object concerns partially explained mechanisms of plant hormone participation in male sex determination in plants, among them in A. phyllitidis gametophytes during GA3 -induced antheridiogenesis. To provide an explanation of the mechanisms of fluorescence and white-light microscopy, cytophotometric, autoradiographic and spectrophotometic methods were used to study cell cycle, the number of nucleoli, the amount of DiOC6 -stained IMN/ER, in which endoplasmic reticulum (ER) constitutes the main part, and its distribution as well as the amounts of proteins and chlorophylls and activities of acidic (Ac) and basic (Ba) phosphatases (Phases)...
March 25, 2019: Micron
https://read.qxmd.com/read/30939359/evidence-for-spinodal-decomposition-in-ti-15mo-quenched-alloy-using-transmission-electron-microscopy
#5
Alphy George, Divakar R
Electron diffraction effect associated with nano-scale periodic modulations observed in a quenched Ti-15 wt%Mo alloy within ω phase forming regime has been investigated in this study by analyzing selected area diffraction patterns and high-resolution phase contrast images. Crystallographic direction of the side bands in electron diffraction associated with the periodic modulation of wavelength 1.3 nm is established as [001]β which is an elastically soft direction for the body-centered cubic lattice. Characteristics of the side bands in the diffraction patterns, such as the correlation of spacing of satellite spots with real-space modulation wavelength and the constancy in the direction of satellites and modulations are interpreted as the proof of phase separation by spinodal decomposition...
March 22, 2019: Micron
https://read.qxmd.com/read/30947034/imaging-photoinduced-surface-potentials-on-hybrid-perovskites-by-real-time-scanning-electron-microscopy
#6
Gabriele Irde, Silvia Maria Pietralunga, Vittorio Sala, Maurizio Zani, James M Ball, Alex J Barker, Annamaria Petrozza, Guglielmo Lanzani, Alberto Tagliaferri
We introduce laser-assisted Time-Resolved SEM (TR-SEM), joining Scanning Electron Microscopy and laser light excitation, to probe the long-term temporal evolution of optically excited charge distributions at the surface of Metal Ammonium Lead Triiodide (MAPbI3 ) hybrid perovskite thin films. Laser-assisted TR-SEM relies on the optically induced local modification of Secondary Electron (SE) detection yield to provide mapping of photoexcited potentials and charge dynamics at surfaces, and qualifies as a complementary approach to near-field probe microscopies and nonlinear photoemission spectroscopies for photovoltage measurements...
March 20, 2019: Micron
https://read.qxmd.com/read/30877951/unravelling-the-nature-of-the-spongy-dark-material-in-aged-turkevich-gold-nanoparticles-colloidal-solutions-by-cytoviva%C3%A2-dark-field-imaging-and-hrtem-analysis
#7
Fernando Menegatti de Melo, Mayara Klimuk Uchiyama, Marcelo Nakamura, Rodrigo Ken Kawassaki, Carlos Pelleschi Taborda, Henrique Eisi Toma
Turkevich gold nanoparticles colloidal solutions undergo further changes after ageing for several weeks or months, and in most cases a spongy dark material can be observed suspended in the red solution. CytoViva® dark-field microscopy images and high resolution transmission electron micrographys (HRTEM) of the strange body played a central role and revealed a fibrous structure, consistent with cellulose, as commonly found in the cell-walls of many fungi. Surprisingly, the interior of the fibers are filled with gold nanoparticles, responsible for the high contrasting images obtained in this work...
March 7, 2019: Micron
https://read.qxmd.com/read/30875488/electron-beam-damage-of-perfluorosulfonic-acid-studied-by-soft-x-ray-spectromicroscopy
#8
Lis G A Melo, Adam P Hitchcock
Scanning transmission X-ray microscopy (STXM) was used to study chemical changes to perfluorosulfonic acid (PFSA) spun cast thin films as a function of dose imparted by exposure of a 200 kV electron beam in a Transmission Electron Microscope (TEM). The relationship between electron beam fluence and absorbed dose was calibrated using a modified version of a protocol based on the positive to negative lithography transition in PMMA [Leontowich et al, J. Synchrotron Rad. 19 (2012) 976]. STXM was used to characterize and quantify the chemical changes caused by electron irradiation of PFSA under several different conditions...
March 7, 2019: Micron
https://read.qxmd.com/read/30878876/strain-measurement-of-particle-reinforced-composites-at-the-microscale-an-approach-towards-concurrent-characterization-of-strain-and-microstructure
#9
Fengguo Zhang, Zhe Chen, Shengyi Zhong, Han Chen, Jun Liu, Qing Yang, Haowei Wang
The mechanical behavior of particle-reinforced composites is largely determined by the interaction between the reinforcing particles and matrix. Although conventional digital image correlation (DIC) allows accurate measurements of strain at microscale, it usually requires preparation of synthetic pattern on the sample surface, which would affect the observation of reinforcing particles. An approach is proposed in this work that relies solely on the reinforcing particles as DIC pattern, thereby enabling concurrent microstructure observation and strain measurement...
March 1, 2019: Micron
https://read.qxmd.com/read/30878875/acquisition-of-3d-models-with-submillimeter-sized-features-from-sem-images-by-use-of-photogrammetry-a-dimensional-comparison-to-microtomography
#10
Gabriel Barbieri, Fabio Pinto da Silva
The use of three-dimensional models for analysis has been increasing in various fields. This study aimed to analyze the process of acquiring 3D meshes by photogrammetry using scanning electron microscopy (SEM) images. 3D models were reconstructed from different numbers of SEM images using a free photogrammetry software. The 3D models obtained were aligned and compared quantitatively to a model obtained by microtomography (microCT). The results suggest that it is possible to reconstruct 3D photogrammetric models with micrometric precision using SEM...
March 1, 2019: Micron
https://read.qxmd.com/read/30861471/a-novel-approach-for-computing-3d-mice-distal-femur-properties-using-high-resolution-micro-computed-tomography-scanning
#11
Brahim Mehadji, Yoseph Ahmed, Jean-Philippe Berteau
One of the most-scanned joints in preclinical animal models dealing with musculoskeletal pathologies is the mouse knee. While three-dimensional (3D) characterization of bone tissue porosity have previously been performed on cortical bone, it has not yet been comprehensively performed for the subchondral bone (SB) and the calcified cartilage (CC), which compose the subchondral mineralized zone (SMZ). Thus, it remains challenging to assess changes that occur in the SMZ of the mouse knee during pathologies such as osteoarthritis...
March 1, 2019: Micron
https://read.qxmd.com/read/30844638/automatic-detection-localization-and-segmentation-of-nano-particles-with-deep-learning-in-microscopy-images
#12
Ayse Betul Oktay, Anıl Gurses
With the growing amount of high resolution microscopy images automatic nano-particle detection, shape analysis and size determination have gained importance for providing quantitative support that gives important information for the evaluation of the material. In this paper, we present a new method for detection of nano-particles and determination of their shapes and sizes simultaneously with deep learning. The proposed method employs multiple output convolutional neural networks (MO-CNN) and has two outputs: first is the detection output that gives the locations of the particles and the other one is the segmentation output for providing the boundaries of the nano-particles...
February 22, 2019: Micron
https://read.qxmd.com/read/30818248/the-effects-of-encapsulation-on-damage-to-molecules-by-electron-radiation
#13
Stephen T Skowron, Sarah L Roberts, Andrei N Khlobystov, Elena Besley
Encapsulation of materials imaged by high resolution transmission electron microscopy presents a promising route to the reduction of sample degradation, both independently and in combination with other traditional solutions to controlling radiation damage. In bulk crystals, the main effect of encapsulation (or coating) is the elimination of diffusion routes of beam-induced radical species, enhancing recombination rates and acting to limit overall damage. Moving from bulk to low dimensional materials has significant effects on the nature of damage under the electron beam...
February 21, 2019: Micron
https://read.qxmd.com/read/30831277/new-approach-to-electron-microscopy-imaging-of-gel-nanocomposites-in-situ
#14
Alejandra Londono-Calderon, Srikanth Nayak, Curtis L Mosher, Surya K Mallapragada, Tanya Prozorov
Characterization of Au-nanocomposites is routinely done with scattering techniques where the structure and ordering of nanoparticles can be analyzed. Imaging of Poloxamer gel-based Au-nanocomposites is usually limited to cryo-TEM imaging of cryo-microtomed thin sections of the specimen. While this approach is applicable for imaging of the individual nanoparticles and gauging their size distribution, it requires altering the state of the specimen and is prone to artifacts associated with preparation protocols...
February 20, 2019: Micron
https://read.qxmd.com/read/30807984/toward-3d-imaging-of-corrosion-at-the-nanoscale-cross-sectional-analysis-of-in-situ-oxidized-tem-samples
#15
Wayne Harlow, Mitra L Taheri
Understanding the effect of microstructural features on corrosion behavior will allow for significant improvements to alloy design for harsh environments. Recently, in-situ TEM has been recognized to offer significant data on corrosion behavior at the nanoscale, but in order for the best information to be acquired, a three dimensional view of the oxidation process is needed so that oxide structure and phase can be identified. Described herein is a new method of sample preparation for transmission electron microscopy (TEM) using a focused ion beam (FIB) to cross-section a previously FIB prepared sample...
February 20, 2019: Micron
https://read.qxmd.com/read/30979573/beam-induced-oxidation-of-mixed-valent-fe-oxyhydr-oxides-green-rust-monitored-by-stem-eels
#16
H M Freeman, J P H Perez, N Hondow, L G Benning, A P Brown
Analytical transmission electron microscopy (TEM) is often used to investigate morphologies, crystal structures, chemical compositions and oxidation states of highly reactive mixed-valent mineral phases. Of prime interest, due to its potential role in toxic metal remediation, is green rust sulphate (GRSO4 ) an FeII -FeIII layered double hydroxide. In this study, we quantified the effects that TEM analysis has on GRSO4 in order to ensure the measured material properties are a result of synthesis and reaction kinetics, and not due to sample preparation and analysis technique...
February 10, 2019: Micron
https://read.qxmd.com/read/30772642/microstructural-evolution-of-a-dual-hardening-steel-during-heat-treatment
#17
Matthias Hofinger, Maximilian Staudacher, Miloslav Ognianov, Christoph Turk, Harald Leitner, Ronald Schnitzer
Dual hardening steels combine precipitation of both secondary hardening carbides and intermetallic phases in a martensitic matrix. Due to this combination, the carbon content necessary to achieve high hardness levels can be reduced, resulting in a decreased amount of large and embrittling carbides. In this study, the influence of different heat treatments on microstructure evolution and secondary hardness is investigated. Different metallographic preparation methods were tested in order to visualize the microstructure...
February 10, 2019: Micron
https://read.qxmd.com/read/30776683/surface-tracked-scanning-ion-conductance-microscopy-a-novel-imaging-technique-for-measuring-topography-correlated-transmembrane-ion-transport-through-porous-substrates
#18
Vijay Venkatesh, Christian Heinemann, Vishnu Baba Sundaresan
Ion transport through porous substrates is ubiquitous in biological and synthetic materials, and fundamental for chemical separation, drug delivery and bio-sensing. Contemporary imaging techniques for simultaneously characterizing topography and ion transport through porous substrates are limited in range and resolution. In this paper, we demonstrate 'surface-tracked scanning ion conductance microscopy' as a technique to image topography of a porous substrate and simultaneously measure voltage-driven transmembrane ion transport...
February 8, 2019: Micron
https://read.qxmd.com/read/30802756/electron-beam-damage-of-epoxy-resin-films-studied-by-scanning-transmission-x-ray-spectromicroscopy
#19
Weiwei Zhang, Lis G de A Melo, Adam P Hitchcock, Nabil Bassim
Focused ion beam coupled with scanning electron microscopy (FIB-SEM) is a popular technique for advanced electron microscopy with applications such as, high-precision site-specific lamella sample preparation for transmission electron microscopy (TEM) and slice-and-view FIB 3-dimensional tomography. Damage caused by the electron imaging component of FIB-SEM may be compounded with damage from the ions during the ion milling process. There are known strategies for mitigating damage from ions and electrons (cryo-SEM, dose-control, voltage control), but the electron damage on common embedding resins for EM has not been explored in detail beyond their resistance to shape-change...
February 7, 2019: Micron
https://read.qxmd.com/read/30742968/description-of-the-third-instar-larva-of-the-stag-beetle-prismognathus-dauricus-motschulsky-1860-coleoptera-scarabaeoidea-lucanidae-using-electron-microscopy
#20
Zong-Fei Qu, Zhi-Chao Jia, Lu Jiang
Lucanidae have long received great attention for their adults. However, differentiating between the larvae of stag beetles is difficult and remains unsatisfactorily resolved due to the microscopic features separating groups. In the current study, the larvae of Prismognathus dauricus Motschulsky, 1860 were investigated using light and scanning electron microscopy. The larvae of P. dauricus are atypical for the following characters: i) the epipharynx possesses anteriorly eleven protophoba arranged in a semi-round line; ii) the par stridens consists of 31 ± 0...
February 4, 2019: Micron
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