Effect of the liquid fragility on flash sintering behavior of oxide nanoparticles

2020 ◽  
Vol 178 ◽  
pp. 261-263 ◽  
Author(s):  
Rachman Chaim
Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1218 ◽  
Author(s):  
Luca Spiridigliozzi ◽  
Lorenzo Pinter ◽  
Mattia Biesuz ◽  
Gianfranco Dell’Agli ◽  
Grazia Accardo ◽  
...  

In this work, ceria-based ceramics with the composition Gd0.14Pr0.06Ce0.8O2-δ and Sm0.14Pr0.06Ce0.8O2-δ, were synthesized by a simple co-precipitation process using either ammonium carbonate or ammonia solution as a precipitating agent. After the calcination, all of the produced samples were constituted by fluorite-structured ceria only, thus showing that both dopant and co-dopant cations were dissolved in the fluorite lattice. The ceria-based nanopowders were uniaxially compacted and consequently flash-sintered using different electrical cycles (including current-ramps). Different results were obtained as a function of both the adopted precipitating agent and the applied electrical cycle. In particular, highly densified products were obtained using current-ramps instead of “traditional” flash treatments (with the power source switching from voltage to current control at the flash event). Moreover, the powders that were synthesized using ammonia solution exhibited a low tendency to hotspot formation, whereas the materials obtained using carbonates as the precipitating agent were highly inhomogeneous. This points out for the first time the unexpected relevance of the precipitating agent (and of the powder shape/degree of agglomeration) for the flash sintering behavior.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1031
Author(s):  
Mattia Biesuz ◽  
Andrea Ometto ◽  
Vincenzo Maria Sglavo

The flash sintering behavior of yttria-stabilized zirconia/alumina composites was investigated to understand the role of the fundamental processing and testing parameters (electric field intensity, electric current limit, thermal insulation, homogeneity and dispersion of the two phases) on densification. A strong relation between the composite compositions and the electric parameters needed to promote flash sintering is revealed. Interestingly, the composite preparation method, which affects the two-phases dispersion homogeneity, was shown to have a relevant effect on the flash onset conditions, where the more homogeneous material is more difficult to be flashed. Moreover, the use of a simple thermal insulation system around the green body allowed to improve the final density of the composites under constant electric current.


2018 ◽  
Vol 6 (10) ◽  
Author(s):  
Hosam Zaghloul ◽  
Doaa A. Shahin ◽  
Ibrahim El- Dosoky ◽  
Mahmoud E. El-awady ◽  
Fardous F. El-Senduny ◽  
...  

Antisense oligonucleotides (ASO) represent an attractive trend as specific targeting molecules but sustain poor cellular uptake meanwhile superparamagnetic iron oxide nanoparticles (SPIONs) offer stability of ASO and improved cellular uptake. In the present work we aimed to functionalize SPIONs with ASO targeting the mRNA of Cyclin B1 which represents a potential cancer target and to explore its anticancer activity. For that purpose, four different SPIONs-ASO conjugates, S-M (1–4), were designated depending on the sequence of ASO and constructed by crosslinking carboxylated SPIONs to amino labeled ASO. The impact of S-M (1–4) on the level of Cyclin B1, cell cycle, ROS and viability of the cells were assessed by flowcytometry. The results showed that S-M3 and S-M4 reduced the level of Cyclin B1 by 35 and 36%, respectively. As a consequence to downregulation of Cyclin B1, MCF7 cells were shown to be arrested at G2/M phase (60.7%). S-M (1–4) led to the induction of ROS formation in comparison to the untreated control cells. Furthermore, S-M (1–4) resulted in an increase in dead cells compared to the untreated cells and SPIONs-treated cells. In conclusion, targeting Cyclin B1 with ASO-coated SPIONs may represent a specific biocompatible anticancer strategy.


2011 ◽  
Vol 4 (6) ◽  
pp. 53-56 ◽  
Author(s):  
Vennila Raj ◽  
◽  
P. Kamaraj P. Kamaraj ◽  
M. Arthanareeswari M. Arthanareeswari ◽  
J. Deepika J. Deepika

2014 ◽  
Vol 29 (10) ◽  
pp. 1039
Author(s):  
TAN Man-Lin ◽  
WANG Yan-Tao ◽  
ZHANG Wei-Li ◽  
FU Dong-Ju ◽  
LI Dong-Shuang ◽  
...  

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