scholarly journals Optimization of negative stage bias potential for faster imaging in large-scale electron microscopy

2021 ◽  
Vol 5 ◽  
pp. 100046
Author(s):  
Ryan Lane ◽  
Yoram Vos ◽  
Anouk H.G. Wolters ◽  
Luc van Kessel ◽  
S. Elisa Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Bias Potential

scholarly journals Optimization of negative stage bias potential for faster imaging in large-scale electron microscopy

2020 ◽  
Author(s):  
Ryan Lane ◽  
Yoram Vos ◽  
Anouk H. G. Wolters ◽  
Luc van Kessel ◽  
Ben N.G. Giepmans ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Image Quality ◽  
Large Scale ◽  
Signal To Noise Ratio ◽  
Negative Bias ◽  
Acquisition Rate ◽  
Bias Potential ◽  
Signal Collection ◽  
Block Face ◽  
Imaging Conditions

AbstractLarge-scale electron microscopy (EM) allows analysis of both tissues and macromolecules in a semi-automated manner, but acquisition rate forms a bottleneck. We reasoned that a negative bias potential may be used to enhance signal collection, allowing shorter dwell times and thus increasing imaging speed. Negative bias potential has previously been used to tune penetration depth in block-face imaging. However, optimization of negative bias potential for application in thin section imaging will be needed prior to routine use and application in large-scale EM. Here, we present negative bias potential optimized through a combination of simulations and empirical measurements. We find that the use of a negative bias potential generally results in improvement of image quality and signal-to-noise ratio (SNR). The extent of these improvements depends on the presence and strength of a magnetic immersion field. Maintaining other imaging conditions and aiming for the same image quality and SNR, the use of a negative stage bias can allow for a 20-fold decrease in dwell time, thus reducing the time for a week long acquisition to less than 8 hours. We further show that negative bias potential can be applied in an integrated correlative light electron microscopy (CLEM) application, allowing fast acquisition of a high precision overlaid LM-EM dataset. Application of negative stage bias potential will thus help to solve the current bottleneck of image acquisition of large fields of view at high resolution in large-scale microscopy.

Phyto-fabrication of Iron Nanoparticles: Characterization and Antibacterial Capacity

2020 ◽  
Vol 16 ◽  
Author(s):  
Asma S. Algebaly ◽  
Afrah E. Mohammed ◽  
Mudawi M. Elobeid
Keyword(s):  
Electron Microscopy ◽  
Plant Extracts ◽  
Large Scale ◽  
Iron Nanoparticles ◽  
Ethanolic Extract ◽  
Green Technology ◽  
Resistant Bacteria ◽  
Scale Production ◽  
Bacterial Strains ◽  
Plant Sources

Introduction: Fabrication of iron nanoparticles (FeNPs) has recently gained a great concern for their varied applications in remediation technologies of the environment. Objective: The current study aimed to fabricate iron nanoparticles by green technology approach using different plant sources, Azadirachta indica leaf and Calligonum comosum root following two extraction methods. Methods: Currently, a mixture of FeCl2 and FeCl3 was used to react with the plant extracts which are considered as reducing and stabilizing agents for the generation of FeNPs in one step. Different techniques were used for FeNPs identification. Results: Immediately after mixing of the two reaction components, the color changed to dark brown as an indication of safe conversion of Fe ions to FeNPs, that later confirmed by zeta sizer, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). FeNPs fabricated by C. comosum showed smaller size when compared by those fabricated by A. indica. Using both plant sources, FeNPs fabricated by the aqueous extract had smaller size in relation to those fabricated by ethanolic extract. Furthermore, antibacterial ability against two bacterial strains was approved. Conclusion: The current results indicated that, at room temperature plant extracts fabricated Fe ion to Fe nanoparticles, suggesting its probable usage for large scale production as well as its suitability against bacteria. It could also be recommended for antibiotic resistant bacteria.

scholarly journals Label-free fluorescence predictions from large-scale correlative light and electron microscopy data

2021 ◽  
Vol 27 (S1) ◽  
pp. 94-95
Author(s):  
Ryan Lane ◽  
Luuk Balkenende ◽  
Simon van Staalduine ◽  
Anouk Wolters ◽  
Ben Giepmans ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Light And Electron Microscopy ◽  
Label Free ◽  
Electron Microscopy Data ◽  
Microscopy Data

Low Temperature Large Scale CVD Synthesis of Nano Onion-Like Fullerenes

2012 ◽  
Vol 490-495 ◽  
pp. 3211-3214 ◽  
Author(s):  
Lei Shan Chen ◽  
Cun Jing Wang
Keyword(s):  
Electron Microscopy ◽  
Low Temperature ◽  
Aluminum Hydroxide ◽  
Large Scale ◽  
Iron Catalyst ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Naoh Solution ◽  
Synthesis Reactions

Synthesis reactions were carried out by chemical vapor deposition using iron catalyst supported on aluminum hydroxide at 400 °C and 420 °C, in the presence of argon as carrier gas and acetylene as carbon source. The aluminum hydroxide support was separated by refluxing the samples in 40% NaOH solution for 2 h and 36% HCl solution for 24 h, respectively. The samples were characterized by field-emission scanning electron microscopy, energy dispersive spectroscopy, high-resolution transmission electron microscopy and X-ray diffraction. The results show that carbon nanotubes were the main products at 420 °C, while large scale high purity nano onion-like fullerenes encapsulating Fe3C, with almost uniform sizes ranging from 10-50 nm, were obtained at the low temperature of 400 °C.

Control of Morphology and Growth Direction of Gallium Nitride Nanostructures

2003 ◽  
Vol 789 ◽  
Author(s):  
Seung Yong Bae ◽  
Hee Won Seo ◽  
Jeunghee Park
Keyword(s):  
Electron Microscopy ◽  
Gallium Nitride ◽  
Large Scale ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Chemical Vapor Deposition Method ◽  
X Ray Diffraction ◽  
Oxide Mixture ◽  
Temperature Range ◽  
Transmission Electron

ABSTRACTVarious shaped single-crystalline gallium nitride (GaN) nanostructures were produced by chemical vapor deposition method in the temperature range of 900–1200 °C. Scanning electron microscopy, transmission electron microscopy, electron diffraction, x-ray diffraction, electron energy loss spectroscopy, Raman spectroscopy, and photoluminescence were used to investigate the structural and optical properties of the GaN nanostructures. We controlled the GaN nanostructures by the catalyst and temperature. The cylindrical and triangular shaped nanowires were synthesized using iron and gold nanoparticles as catalysts, respectively, in the temperature range of 900 – 1000 °C. We synthesized the nanobelts, nanosaws, and porous nanowires using gallium source/ boron oxide mixture. When the temperature of source was 1100 °C, the nanobelts having a triangle tip were grown. At the temperature higher up to 1200 °C the nanosaws and porous nanowires were formed with a large scale. The cylindrical nanowires have random growth direction, while the triangular nanowires have uniform growth direction [010]. The growth direction of the nanobelts is perpendicular to the [010]. Interestingly, the nanosaws and porous nanowires exhibit the same growth direction [011]. The shift of Raman, XRD, and PL bands from those of bulk was correlated with the strains of the GaN nanostructures.

scholarly journals Automatic instance segmentation of mitochondria in electron microscopy data

2021 ◽  
Author(s):  
Luke Nightingale ◽  
Joost de Folter ◽  
Helen Spiers ◽  
Amy Strange ◽  
Lucy M Collinson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Machine Learning Algorithms ◽  
Public Repository ◽  
Post Processing ◽  
Human Cortex ◽  
Electron Microscopy Data ◽  
Processing Procedure ◽  
Microscopy Data ◽  
Instance Segmentation

We present a new method for rapid, automated, large-scale 3D mitochondria instance segmentation, developed in response to the ISBI 2021 MitoEM Challenge. In brief, we trained separate machine learning algorithms to predict (1) mitochondria areas and (2) mitochondria boundaries in image volumes acquired from both rat and human cortex with multi-beam scanning electron microscopy. The predictions from these algorithms were combined in a multi-step post-processing procedure, that resulted in high semantic and instance segmentation performance. All code is provided via a public repository.

AQUEOUS SYNTHESIS OF HIGH QUANTUM YIELD AND MONODISPERSED THIOL-CAPPED CdxZn1-xTe QUANTUM DOTS BASED ON ELECTROCHEMICAL METHOD

NANO ◽  
2012 ◽  
Vol 07 (02) ◽  
pp. 1250011 ◽  
Author(s):  
JUNWEI LI ◽  
YANG JIANG ◽  
YUGANG ZHANG ◽  
DI WU ◽  
ANQI LUO ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Electrochemical Method ◽  
Large Scale ◽  
Ostwald Ripening ◽  
Visible Absorption ◽  
Aqueous Synthesis ◽  
Transmission Electron

A facile green approach has been developed to control the growth regime in the aqueous synthesis of CdxZn1-xTe semiconductor quantum dots (QDs) based on the electrochemistry method. The Low growth temperature and slow injection of Te precursor are used to prolong the diffusion controlled stage and thus suppress Ostwald ripening during the nanocrystal growth. The experimental results showed that a low concentration of Te precursor will definitely influence the growth procedure. The UV–visible absorption spectra, as well as transmission electron microscopy (TEM) shows the QDs a good monodispersity at any interval of the reaction procedure. The high-resolution transmission electron microscopy (HRTEM) images and powder X-ray diffraction (XRD) pattern suggested that the as-prepared QDs have high crystallinity and cubic structure. The size and composition-dependent fluorescent emission wavelength of the resultant CdxZn1-xTe alloyed QDs can be tuned from 460 to 610 nm, and their photoluminescent quantum yield can reach up to 70%. Especially in the wavelength range of 510–578 nm, the overall PL QYs of the as-prepared CdxZn1-xTe QDs were above 50%. The current work suggests that electrochemical method is an attractive approach to the synthesis of high-quality II-VI ternary alloyed semiconductor QDs at large-scale with a prominent cost advantage.

Abstract WP313: Liposomes With Anti-Fibrin Protein Binders to Target Clot in Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Robert Mikulik ◽  
Hana Petroková ◽  
Josef Mašek ◽  
Milan Kuchar ◽  
Andrea Vítecková Wünschová ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Targeted Delivery ◽  
Animal Studies ◽  
Large Scale ◽  
Small Diameter ◽  
Titration Calorimetry ◽  
Ribosome Display ◽  
Main Challenge ◽  
Protein Binders

Introduction: Direct clot targeting represents attractive concept for clot imaging as well as targeted delivery of drugs, e.g. thrombolytics. Small protein binders attached to nanoliposomes may target thrombi and deliver drugs although selective affinity to fibrin and not fibrinogen is the main challenge. Methods: For identification and preparation of fibrin-specific artificial protein binders derived from scaffolds of albumin-binding domain (ABD) of streptococcal protein G, a highly complex ABD-derived combinatorial library in combination with ribosome display selection was used. In vitro models were used to document delivery of nanoliposomes to human thrombi. Results: A recombinant target as a stretch of three identical fibrin fragments of 16 amino acid peptides of the Bβ chain fused to TolA protein carrying polyhistidylated tag and Avitag was constructed. Ribosome display was followed by large-scale ELISA screening of protein binders. Only four protein variants had selective affinity to human fibrin - see figure 1A. The most selective, variant D7, was modified by C-terminal FLAG/His 6 or His 6 /His 6 tag in order to be attached onto the surface of nanoliposomes. The electron microscopy then confirmed the structure of nanoliposome-binder particles. Isothermal titration calorimetry provided dissociation constant for liposome-binder metallochelating bond in the range 10 -7 to 10 -9 for mono- and double-HisTag forms. In vitro, in silicone replica of small diameter artery, the confocal and scanning electron microscopy confirmed a successful binding of D7-attached- to-nanoliposomes to fibrin fibres, see figure 1B. Conclusions: We developed binders relatively selective to fibrin, attached them to nanoliposomes, and documented targeting of fibrin in vitro. As the next step, selectivity needs to be now documented in animal studies.

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