Transmission electron microscopy of aluminum implanted and annealed (100) Si: Direct evidence of aluminum precipitate formation

1986 ◽  
Vol 49 (18) ◽  
pp. 1169-1171 ◽  
Author(s):  
D. K. Sadana ◽  
M. H. Norcott ◽  
R. G. Wilson ◽  
U. Dahmen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Direct Evidence ◽  
Precipitate Formation ◽  
Transmission Electron

Detection of Amorphous Silica in Air-Oxidized Ti3SiC2 at 500–1000°C by NMR and SIMS

2010 ◽  
Vol 434-435 ◽  
pp. 169-172 ◽  
Author(s):  
Wei Kong Pang ◽  
It Meng Low ◽  
J.V. Hanna
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Transmission Electron Microscopy ◽  
Amorphous Silica ◽  
Direct Evidence ◽  
Secondary Ion Mass Spectrometry ◽  
Amorphous Sio2 ◽  
Transmission Electron ◽  
First Time ◽  
Secondary Ion

The use of secondary-ion mass spectrometry (SIMS), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti3SiC2 oxidised at 500–1000°C is described. The formation of an amorphous SiO2 layer and its growth in thickness with temperature was monitored using dynamic SIMS. Results of NMR and TEM verify for the first time the direct evidence of amorphous silica formation during the oxidation of Ti3SiC2 at 1000°C.

scholarly journals Clostridium perfringens produces an adhesive pilus required for the pathogenesis of necrotic enteritis in poultry

2021 ◽  
Author(s):  
D. Lepp ◽  
Y. Zhou ◽  
S. Ojha ◽  
I. Mehdizadeh Gohari ◽  
J. Carere ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Surface ◽  
Clostridium Perfringens ◽  
Direct Evidence ◽  
Necrotic Enteritis ◽  
Null Mutant ◽  
Transmission Electron ◽  
Mutant Strains ◽  
Important Disease

Clostridium perfringens Type G strains cause necrotic enteritis (NE) in poultry, an economically important disease that is a major target of in-feed antibiotics. NE is a multifactorial disease, involving not only the critically-important NetB toxin, but also additional virulence and virulence-associated factors. We previously identified a C. perfringens chromosomal locus (VR-10B) associated with disease-causing strains that is predicted to encode a sortase-dependant pilus. In the current study, we sought to provide direct evidence for the production of a pilus by C. perfringens and establish its role in NE pathogenesis. Pilus structures in virulent C. perfringens strain CP1 were visualized by transmission electron microscopy (TEM) of immuno-gold labelled cells. Filamentous structures were observed extending from the cell surface in wild-type CP1, but not from isogenic pilin-null mutant strains. In addition, immuno-blotting of cell surface proteins demonstrated that CP1, but not the null mutant strains, produced a high molecular weight ladder-like pattern characteristic of a pilus polymer. Binding to collagen types I, II and IV was significantly reduced (Tukey’s; p<0.01) in all three pilin mutants compared to CP1, and could be specifically blocked by CnaA and FimA antisera, indicating that these pilins participate in adherence. Furthermore, both fimA and fimB null mutants were both severely attenuated in their ability to cause disease in an in vivo chicken NE challenge model. Together, these results provide the first direct evidence for the production of a sortase-dependant pilus by C. perfringens, and confirm its critical role in NE pathogenesis and collagen-binding. Importance In necrotic enteritis (NE), an intestinal disease of chickens, Clostridium perfringens cells adhere tightly to damaged intestinal tissue, but the factors involved are not known. We previously discovered a cluster of C. perfringens genes predicted to encode a pilus, a hair-like bacterial surface structure commonly involved in adherence. In the current study, we have directly imaged this pilus using transmission electron microscopy (TEM). We also show that inactivation of the pilus genes stops pilus production, significantly reducing the bacterium's ability to bind collagen and cause disease. Importantly, this is the first direct evidence for the production of a sortase-dependant pilus by C. perfringens, revealing a promising new target for developing therapeutics to combat this economically important disease.

Different routes to the formation of C54 TiSi2 in the presence of surface and interface molybdenum: A transmission electron microscopy study

2002 ◽  
Vol 17 (4) ◽  
pp. 784-789 ◽  
Author(s):  
Z-B. Zhang ◽  
S-L. Zhang ◽  
D-Z. Zhu ◽  
H-J. Xu ◽  
Y. Chen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Direct Evidence ◽  
Sample Surface ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Cross Sectional ◽  
Surface And Interface ◽  
Si Substrates ◽  
Transmission Electron

Direct evidence revealing fundamental differences in sequence of phase formation during the growth of TiSi2 in the presence of an ultrathin surface or interface Mo layer is presented. Results of cross-sectional transmission electron microscopy showed that when the Mo layer was present at the interface between Ti films and Si substrates, C40 (Mo,Ti)Si2 formed at the interface, and Ti5Si3 grew on top after annealing at 550 °C. Additionally, both C54 and C40 TiSi2 were found in the close vicinity of the C40 (Mo,Ti)Si2 grains. No C49 grains were detected. Raising the annealing temperature to 600 °C led to the formation of C54 TiSi2 at the expense of Ti5Si3, and the interfacial C40 (Mo,Ti)Si2 also began to transform into C54 (Mo,Ti)Si2 at 600 °C. When the Mo was deposited on top of Ti, the silicide film was almost solely composed of C49 TiSi2 at 600 °C. However, a small amount of (Mo,Ti)5Si3 was still present in the vicinity of the sample surface. Upon annealing at 650 °C, only the C54 phase was found throughout the entire TiSi2 layer with a surface (Mo,Ti)Si2 on top of TiSi2. Hence, it was unambiguously shown that in the presence of surface versus interface Mo, different routes were taken to the formation of C54 TiSi2.

scholarly journals Transmission electron microscopy enables the reconstruction of the catenane and ring forms of CS2 hydrolase

2014 ◽  
Vol 50 (71) ◽  
pp. 10281-10283 ◽  
Author(s):  
Joseph Che-Yen Wang ◽  
Adam Zlotnick ◽  
Jasmin Mecinović
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Direct Evidence ◽  
Protein Assemblies ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Microscopic Studies ◽  
Good Agreement

Transmission electron microscopic studies on CS2 hydrolase provide direct evidence for the existence of the hexadecameric catenane and octameric ring topologies. Reconstructions of both protein assemblies are in good agreement with crystallographic analyses.

scholarly journals Direct evidence for uptake of intact liposomes encapsulating silver sulfadiazine by cultured human keratinocytes based on combined transmission electron microscopy and X-ray microanalysis.

1997 ◽  
Vol 41 (3) ◽  
pp. 717-719 ◽  
Author(s):  
M Schaller ◽  
R Wurm ◽  
H C Korting
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Direct Evidence ◽  
Human Keratinocytes ◽  
Silver Sulfadiazine ◽  
Active Part ◽  
X Ray ◽  
Transmission Electron ◽  
Dense Marker

Cultured human keratinocytes were exposed to liposomally encapsulated silver sulfadiazine, free silver sulfadiazine, silver sulfadiazine cream, and a corresponding vehicle for 5 min to 24 h. Phagocytosis of intact liposomes by keratinocytes was demonstrated in vitro by combined X-ray microanalysis and electron microscopy. Silver as an active part of the antimicrobial served as an electron-dense marker.

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