Electron Microscopy
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2022 ◽  
Vol 321 ◽  
pp. 126326
Author(s):  
Gladis Aparecida Galindo Reisemberger de Souza ◽  
Ramón Sigifredo Cortés Paredes ◽  
Frieda Saicla Barros ◽  
Gustavo Bavaresco Sucharski ◽  
Sebastião Ribeiro Junior ◽  
...  

Scanning ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-12
Author(s):  
Meng Du ◽  
Haifeng Mei ◽  
Ya Liu

Phase equilibria of the Fe-Al-Ni-O system at 750°C were determined by scanning electron microscopy coupled with energy-dispersive X-ray spectrometer and X-ray power diffraction. 54 alloys were prepared with weighted metal and Ni2O3 powder and were annealed at 750°C for 45 days. Two four-phase equilibrium regions and three three-phase equilibrium regions were confirmed, and the boundary between spinel and corundum was obtained. Comparing with the Fe-Al-Ni-O oxidation diagram at 750°C calculated with FSstel and FToxid databases, the phase boundary of the spinel and corundum oxides from experiments was inclined to the Ni-Al side. The determined relationship between primary oxides and alloy composition in this work can be used as a reference for the preparation of the oxide film by selective oxidation.


PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0261928
Author(s):  
Takuya Aikawa ◽  
Noritoshi Maehara ◽  
Yu Ichihara ◽  
Hayato Masuya ◽  
Katsunori Nakamura ◽  
...  

Wolbachia are obligatory endosymbiotic α-proteobacteria found in many arthropods. They are maternally inherited, and can induce reproductive alterations in the hosts. Despite considerable recent progress in studies on the associations between Wolbachia and various taxonomic groups of insects, none of the researches have revealed the effects of Wolbachia on longicorn beetles as the host insect. Acalolepta fraudatrix is a forest longicorn beetle that is distributed in East Asia. In this study, the relationship between Wolbachia and A. fraudatrix was investigated. Out of two populations of A. fraudatrix screened for Wolbachia using the genes ftsZ, wsp, and 16S rRNA, only one of the populations showed detection of all three genes indicating the presence of Wolbachia. Electron microscopy and fluorescent in situ hybridization also confirmed that the A. fraudatrix population was infected with Wolbachia. Sequencing the wsp genes derived from single insects revealed that two strains of Wolbachia coexisted in the insects based on the detection of two different sequences of the wsp gene. We designated these strains as wFra1 and wFra2. The bacterial titers of wFra1 were nearly 2-fold and 3-fold higher than wFra2 in the testes and ovaries, respectively. The two strains of Wolbachia in the insects were completely eliminated by rearing the insects on artificial diets containing 1% concentration of tetracycline for 1 generation. Reciprocal crosses between Wolbachia-infected and Wolbachia-uninfected A. fraudatrix demonstrated that only eggs produced by the crosses between Wolbachia-infected males and Wolbachia-uninfected females did not hatch, indicating that Wolbachia infecting A. fraudatrix causes cytoplasmic incompatibility in the host insect. This is the first report showing the effect of Wolbachia on reproductive function in a longicorn beetle, A. fraudatrix.


2022 ◽  
Vol 12 ◽  
Author(s):  
Sarangapani Sreelatha ◽  
Nadimuthu Kumar ◽  
Tan Si Yin ◽  
Sarojam Rajani

The bacterium Xanthomonas campestris pv. campestris (Xcc) causes black rot disease in cruciferous crops, resulting in severe yield loss worldwide. The excessive use of chemical pesticides in agriculture to control diseases has raised significant concern about the impact on the environment and human health. Nanoparticles have recently gained significant attention in agriculture owing to their promising application in plant disease control, increasing soil fertility and nutrient availability. In the current study, we synthesized thymol-loaded chitosan nanoparticles (TCNPs) and assessed their antibacterial activity against Xcc. The synthesis of TCNPs was confirmed by using ultraviolet–visible spectroscopy. Fourier-transform infrared spectroscopy, transmission electron microscopy, and scanning electron microscopy analysis revealed the functional groups, size, and shape of TCNPs, with sizes ranging from 54 to 250 nm, respectively. The antibacterial activity of TCNPs against Xcc was investigated in vitro by liquid broth, cell viability, and live dead staining assay, and all of them demonstrated the antibacterial activity of TCNPs. Furthermore, TCNPs were found to directly inhibit the growth of Xcc by suppressing the growth of biofilm formation and the production of exopolysaccharides and xanthomonadin. The ultrastructure studies revealed membrane damage in TCNP-treated Xcc cells, causing a release of intracellular contents. Headspace/gas chromatography (GC)–mass spectrometry (MS) analysis showed changes in the volatile profile of Xcc cells treated with TCNPs. Increased amounts of carbonyl components (mainly ketones) and production of new volatile metabolites were observed in Xcc cells incubated with TCNPs. Overall, this study reveals TCNPs as a promising antibacterial candidate against Xcc.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 603
Author(s):  
Natalia Rońda ◽  
Krzysztof Grzelak ◽  
Marek Polański ◽  
Julita Dworecka-Wójcik

This work investigates the effect of layer thickness on the microstructure and mechanical properties of M300 maraging steel produced by Laser Engineered Net Shaping (LENS®) technique. The microstructure was characterized using light microscopy (LM) and scanning electron microscopy (SEM). The mechanical properties were characterized by tensile tests and microhardness measurements. The porosity and mechanical properties were found to be highly dependent on the layer thickness. Increasing the layer thickness increased the porosity of the manufactured parts while degrading their mechanical properties. Moreover, etched samples revealed a fine cellular dendritic microstructure; decreasing the layer thickness caused the microstructure to become fine-grained. Tests showed that for samples manufactured with the chosen laser power, a layer thickness of more than 0.75 mm is too high to maintain the structural integrity of the deposited material.


Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
George Pchelarov ◽  
Dzhamal Uzun ◽  
Sasho Vassilev ◽  
Elena Razkazova-Velkova ◽  
Ognian Dimitrov ◽  
...  

Described herewith is an electrochemical method to decontaminate sulphur compounds. Studies were carried out of sulphites (SO32−) oxidation on a range of anode catalysts. The electrocatalysts were characterized by scanning electron microscopy, XRD, XPS and BET. Polarization curves were recorded of electrodes incorporating lyophilized higher fullerenes and manganese oxides. The experiments showed that lyophilized higher fullerenes and C60/C70 fullerene catalysts in conjunction with manganese oxides electrochemically convert sulphites (SO32−) to sulphates (SO42−). The oxidation products do not poison the electrodes. The XPS analysis shows that the catalysts incorporating DWCNTs, MWCNTs and higher fullerenes have a higher concentration of sp3C carbon bonding leading to higher catalytic activity. It is ascertained that higher fullerenes play a major role in the synthesis of more effective catalysts. The electrodes built by incorporating lyophilized catalysts containing higher fullerenes and manganese oxides are shown as most promising in the effective electrochemical decontamination of industrial and natural wastewaters.


Author(s):  
Osamu Ueda ◽  
Makoto Kasu ◽  
Hirotaka Yamaguchi

Abstract This paper reviews the status of characterization of defects in β-Ga2O3 crystals grown by edge-defined film-fed growth and hydride vapor phase epitaxy using chemical etching, scanning electron microscopy, focused ion beam scanning ion microscopy, X-ray topography (XRT), and transmission electron microscopy (TEM). The observed defects are classified into four types: dislocations, stacking faults (SFs), twins, and plate-like nanovoids (PNVs). First, we present the detailed characterization of dislocations in the crystal by chemical etching, XRT, and TEM, and discuss possible slip systems. Next, we describe XRT analyses of two types of SFs: SFs 1 lying on the (2 ̅01) plane and SFs 2 on the (111) and (11 ̅1) planes. We describe the results for twins found in crystals via high-resolution TEM and electron diffraction analysis, and PNVs corresponding to etch pits on the (010) plane. Finally, we discuss possible generation mechanisms of the defects and their influence on device characteristics.


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