scholarly journals Directed evolution of artificial repeat proteins as habit modifiers for the morphosynthesis of (111)-terminated gold nanocrystals

Nanoscale ◽  
2019 ◽  
Vol 11 (37) ◽  
pp. 17485-17497 ◽  
Author(s):  
Janak Prasad ◽  
Sébastien Viollet ◽  
Kargal L. Gurunatha ◽  
Agathe Urvoas ◽  
Agathe C. Fournier ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Chemical Affinity ◽  
High Chemical ◽  
Gold Nanocrystals ◽  
Repeat Proteins ◽  
Structural Selectivity

Artificial repeat proteins are selected by directed evolution for their high chemical affinity for gold and structural selectivity for (111) facets. The proteins chaperone the growth of (111)-terminated nanocrystals and form a functional shell.

Stress Enhanced Arsenic Diffusion In Titanium Salicided Junctions By Implantation Into C49 TiSi2 and Rapid Thermal Annealing

1999 ◽  
Vol 564 ◽  
Author(s):  
Dong Kyun Sohn ◽  
Ji-Soo Park ◽  
Jong-Uk Bae ◽  
Yun-Jun Hub ◽  
Jin Won Park
Keyword(s):  
Tensile Stress ◽  
Leakage Current ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Chemical Affinity ◽  
Si Substrate ◽  
High Chemical ◽  
Reverse Leakage Current ◽  
Shallow Junctions ◽  
Diffusion Source

AbstractWe studied reverse leakage current in n+/p titanium-salicided shallow junctions using C49 Ti-silicide as a diffusion source. After Ti deposition, rapid thermal annealing (RTA) was performed to form the C49 Ti-silicide. Subsequently, arsenic ions were implanted and a 2nd RTA was carried out at 850 °C to form the low resistivity C54 Ti-silicide. In spite of no drive-in process following the 2nd annealing, the implanted As diffused well into Si substrate and the reverse leakage current of the n+/p junctions was reduced to two orders of magnitude lower. Since the high chemical affinity of As to Ti-silicide trapped the dopant in the silicide, it has been known that Ti or Ti-silicide cannot be used as a diffusion source. However, in this work, we found that the C49 Ti-silicide acted as a diffusion source of As ions. The reason of fast diffusivity is attributed to the generation of high tensile stress induced by As implantation.

Thoughts on Chemical Affinity

1882 ◽  
Vol 14 (347supp) ◽  
pp. 5538-5539
Author(s):  
Charles Morris
Keyword(s):  
Chemical Affinity

Chemical Affinity

1905 ◽  
Vol 60 (1547supp) ◽  
pp. 24792-24794 ◽  
Author(s):  
Oliver J. Lodge
Keyword(s):  
Chemical Affinity

Directed Evolution of P450 Fatty Acid Decarboxylases via High-Throughput Screening Towards Improved Catalytic Activity

2019 ◽  
Author(s):  
Huifang Xu ◽  
Weinan Liang ◽  
Linlin Ning ◽  
Yuanyuan Jiang ◽  
Wenxia Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fatty Acid ◽  
Directed Evolution ◽  
High Throughput ◽  
High Throughput Screening ◽  
Colorimetric Detection ◽  
Screening Method ◽  
Random Mutagenesis ◽  
Direct Production ◽  
Consumption Activity

P450 fatty acid decarboxylases (FADCs) have recently been attracting considerable attention owing to their one-step direct production of industrially important 1-alkenes from biologically abundant feedstock free fatty acids under mild conditions. However, attempts to improve the catalytic activity of FADCs have met with little success. Protein engineering has been limited to selected residues and small mutant libraries due to lack of an effective high-throughput screening (HTS) method. Here, we devise a catalase-deficient <i>Escherichia coli</i> host strain and report an HTS approach based on colorimetric detection of H<sub>2</sub>O<sub>2</sub>-consumption activity of FADCs. Directed evolution enabled by this method has led to effective identification for the first time of improved FADC variants for medium-chain 1-alkene production from both DNA shuffling and random mutagenesis libraries. Advantageously, this screening method can be extended to other enzymes that stoichiometrically utilize H<sub>2</sub>O<sub>2</sub> as co-substrate.

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