scholarly journals A modified ‘NanoSuit®’ preserves wet samples in high vacuum: direct observations on cells and tissues in field-emission scanning electron microscopy

2017 ◽  
Vol 4 (3) ◽  
pp. 160887 ◽  
Author(s):  
Yasuharu Takaku ◽  
Hiroshi Suzuki ◽  
Hideya Kawasaki ◽  
Isao Ohta ◽  
Daisuke Ishii ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Structural Changes ◽  
Cultured Cells ◽  
High Vacuum ◽  
Insect Larvae ◽  
Direct Observations ◽  
High Vacuum Environment ◽  
Scanning Electron

Although field-emission scanning electron microscopy (FE-SEM) has proven very useful in biomedical research, the high vacuum required (10 −3 to 10 −7  Pa) precludes direct observations of living cells and tissues at high resolution and often produces unwanted structural changes. We have previously described a method that allows the investigator to keep a variety of insect larvae alive in the high vacuum environment of the electron microscope by encasing the organisms in a thin, vacuum-proof suit, the ‘NanoSuit®'. However, it was impossible to protect wet tissues freshly excised from intact organisms or cultured cells. Here we describe an improved ‘NanoSuit' technique to overcome this limitation. We protected the specimens with a surface shield enhancer (SSE) solution that consists of glycerine and electrolytes and found that the fine structure of the SSE-treated specimens is superior to that of conventionally prepared specimens. The SSE-based NanoSuit affords a much stronger barrier to gas and/or liquid loss than the previous NanoSuit did and, since it allows more detailed images, it could significantly help to elucidate the ‘real' organization of cells and their functions.

The Performance of a Thermal Field Emission Gun

1975 ◽  
Vol 33 ◽  
pp. 146-147
Author(s):  
Dennis M. Maher ◽  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Thermal Field ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Magnetic Alignment ◽  
Stable Operation ◽  
Alignment System ◽  
Scanning Electron

Although the "cold" field emission gun has been used successfully for both transmission and scanning electron microscopy it requires ultra-high vacuum which is not obtained easily when such a gun is interfaced to a conventional microscope system. Recently, the "thermal" field emission gun (TFEG) in which the emitting tip is held at around 1700°K has been proposed as an alternative electron source for such applications. Under this condition the tip is cleaned continuously, and surface asperities are smoothed, therefore stable operation is possible in a high vacuum. In this paper we report on the build-up characteristics, current stability and brightness of a TFEG which has been interfaced to a JEOL JEM 100B microscope equipped with a scanning attachment. The gun consists of a (111) tungsten emitter set on a rhenium filament, three anodes and a two stage magnetic alignment system. The gun chamber is ion pumped to a pressure in the range 6xl0-8 to 2xl0-9 torr.

A New Image Processing Technique for STEM

1974 ◽  
Vol 32 ◽  
pp. 432-433
Author(s):  
Yasushi Kokubo ◽  
Hirotami Koike ◽  
Teruo Someya
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Scanning Electron Microscopy ◽  
Elastic Scattering ◽  
Field Emission ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Energy Analyzer ◽  
Scanning Microscope ◽  
Scanning Electron

One of the advantages of scanning electron microscopy is the capability for processing the image contrast, i.e., the image processing technique. Crewe et al were the first to apply this technique to a field emission scanning microscope and show images of individual atoms. They obtained a contrast which depended exclusively on the atomic numbers of specimen elements (Zcontrast), by displaying the images treated with the intensity ratio of elastically scattered to inelastically scattered electrons. The elastic scattering electrons were extracted by a solid detector and inelastic scattering electrons by an energy analyzer. We noted, however, that there is a possibility of the same contrast being obtained only by using an annular-type solid detector consisting of multiple concentric detector elements.

scholarly journals A Review on Enhancing the Antibacterial Activity of ZnO: Mechanisms and Microscopic Investigation

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Buzuayehu Abebe ◽  
Enyew Amare Zereffa ◽  
Aschalew Tadesse ◽  
H. C. Ananda Murthy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Antibacterial Activity ◽  
Field Emission ◽  
Volume Ratio ◽  
Electronic Configuration ◽  
Microscopic Investigation ◽  
Electron Microscopic ◽  
Active Materials ◽  
Scanning Electron

Abstract Metal oxide nanomaterials are one of the preferences as antibacterial active materials. Due to its distinctive electronic configuration and suitable properties, ZnO is one of the novel antibacterial active materials. Nowadays, researchers are making a serious effort to improve the antibacterial activities of ZnO by forming a composite with the same/different bandgap semiconductor materials and doping of ions. Applying capping agents such as polymers and plant extract that control the morphology and size of the nanomaterials and optimizing different conditions also enhance the antibacterial activity. Forming a nanocomposite and doping reduces the electron/hole recombination, increases the surface area to volume ratio, and also improves the stability towards dissolution and corrosion. The release of antimicrobial ions, electrostatic interaction, reactive oxygen species (ROS) generations are the crucial antibacterial activity mechanism. This review also presents a detailed discussion of the antibacterial activity improvement of ZnO by forming a composite, doping, and optimizing different conditions. The morphological analysis using scanning electron microscopy, field emission-scanning electron microscopy, field-emission transmission electron microscopy, fluorescence microscopy, and confocal microscopy can confirm the antibacterial activity and also supports for developing a satisfactory mechanism. Graphical abstract Graphical abstract showing the metal oxides antibacterial mechanism and the fluorescence and scanning electron microscopic images.

scholarly journals Redox Mechanism of Azathioprine and Its Interaction with DNA

2021 ◽  
Vol 22 (13) ◽  
pp. 6805
Author(s):  
Mihaela-Cristina Bunea ◽  
Victor-Constantin Diculescu ◽  
Monica Enculescu ◽  
Horia Iovu ◽  
Teodor Adrian Enache
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Scanning Electron Microscopy ◽  
Structural Changes ◽  
Differential Pulse ◽  
Immunosuppressive Drug ◽  
Redox Mechanism ◽  
Before And After ◽  
Dna Film ◽  
Scanning Electron

The electrochemical behavior and the interaction of the immunosuppressive drug azathioprine (AZA) with deoxyribonucleic acid (DNA) were investigated using voltammetric techniques, mass spectrometry (MS), and scanning electron microscopy (SEM). The redox mechanism of AZA on glassy carbon (GC) was investigated using cyclic and differential pulse (DP) voltammetry. It was proven that the electroactive center of AZA is the nitro group and its reduction mechanism is a diffusion-controlled process, which occurs in consecutive steps with formation of electroactive products and involves the transfer of electrons and protons. A redox mechanism was proposed and the interaction of AZA with DNA was also investigated. Morphological characterization of the DNA film on the electrode surface before and after interaction with AZA was performed using scanning electron microscopy. An electrochemical DNA biosensor was employed to study the interactions between AZA and DNA with different concentrations, incubation times, and applied potential values. It was shown that the reduction of AZA molecules bound to the DNA layer induces structural changes of the DNA double strands and oxidative damage, which were recognized through the occurrence of the 8-oxo-deoxyguanosine oxidation peak. Mass spectrometry investigation of the DNA film before and after interaction with AZA also demonstrated the formation of AZA adducts with purine bases.

Ultrastructural Features of Mammalian Sperm: Applications of Cold Field-Emission Scanning Electron Microscopy

2006 ◽  
Vol 12 (S02) ◽  
pp. 232-233
Author(s):  
A Klaus ◽  
G Hunnicutt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Mammalian Sperm ◽  
Scanning Electron

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2005

Study on the Element Composition of Southern Celadon Porcelain and Coloring Mechanism

2014 ◽  
Vol 484-485 ◽  
pp. 96-99
Author(s):  
Xue Wen Gao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Emission ◽  
Element Composition ◽  
Molar Ratio ◽  
Experimental Sample ◽  
Fe Content ◽  
Firing System ◽  
Pink Coloration ◽  
Scanning Electron

This paper mainly discusses the Si/Al molar ratio, RO/R2O molar ratio, Fe content, glazing and firing system on the thickness of Longquan Celadon pink coloring effects, and using a colorimeter, field emission scanning electron microscopy were used to analyze better experimental sample microstructure and color and so on. We explored the Longquan Celadon of pink coloration mechanism.

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