Chemically Modified Gold/Silver Superatoms as Artificial Elements at Nanoscale: Design Principles and Synthesis Challenges

2021 ◽  
Vol 143 (4) ◽  
pp. 1683-1698
Author(s):  
Shinjiro Takano ◽  
Tatsuya Tsukuda
2020 ◽  
Vol 15 (2) ◽  
pp. 53-56
Author(s):  
A.K. Trofimchuk ◽  
V.N. Losev ◽  
V.V. V.V. ◽  
E.V. Elsuf’ev ◽  
N.V. Gudymа

The synthesis of new complexing adsorbents with thiophenol (MPhS) and aminobenzthiazolpropyl (ABTS) groups grafted onto the surface of silica gels are considered. The extraction of precious metals (Au(III), Ag(I), Pd(II), Pt(II,IV), Rh(III), Ir(IV), Ru(IV), Os(IV)) from solutions of hydrochloric acid by MPhS and ABTS adsorbents. Contact time, acidity, temperature (25 – 95 °C), and the presence of a labilization agent tin(II) chloride is examined. It is shown that the adsorption properties of MPhS for precious metals are better than ABTS. It was proved by luminescence spectroscopy that gold, silver and platinum in the surface complexes with sulfur-containing groups are in lower oxidation states; and by the EPR method it was proved that ruthenium and osmium in surface complexes are in oxidation state +3. The formation of luminescent Ag(I), Au(I) and Pt(II) complexes on the surface of the MPhS, colored Ru(III) complexes on the surface of MPhS and ABTS, and mixed-ligand complexes of Pt(II) with surface aminobenzthiazole groups and Michler’s thioketone were used for developing methods of their adsorption luminescent, adsorption-photometric and test determinatio


2020 ◽  
Vol 48 (2) ◽  
pp. 399-409
Author(s):  
Baizhen Gao ◽  
Rushant Sabnis ◽  
Tommaso Costantini ◽  
Robert Jinkerson ◽  
Qing Sun

Microbial communities drive diverse processes that impact nearly everything on this planet, from global biogeochemical cycles to human health. Harnessing the power of these microorganisms could provide solutions to many of the challenges that face society. However, naturally occurring microbial communities are not optimized for anthropogenic use. An emerging area of research is focusing on engineering synthetic microbial communities to carry out predefined functions. Microbial community engineers are applying design principles like top-down and bottom-up approaches to create synthetic microbial communities having a myriad of real-life applications in health care, disease prevention, and environmental remediation. Multiple genetic engineering tools and delivery approaches can be used to ‘knock-in' new gene functions into microbial communities. A systematic study of the microbial interactions, community assembling principles, and engineering tools are necessary for us to understand the microbial community and to better utilize them. Continued analysis and effort are required to further the current and potential applications of synthetic microbial communities.


1989 ◽  
Vol 61 (01) ◽  
pp. 131-136 ◽  
Author(s):  
Richard A Harvey ◽  
Hugh C Kim ◽  
Jonathan Pincus ◽  
Stanley Z Trooskin ◽  
Josiah N Wilcox ◽  
...  

SummaryTissue plasminogen activator labeled with radioactive iodine (125I-tPA) was immobilized on vascular prostheses chemically modified with a thin coating of water-insoluble surfactant, tridodecylmethylammonium chloride (TDM AC). Surfactant- treated Dacron, polytetrafluoroethylene (PTFE), silastic, polyethylene and polyurethane bound appreciable amounts of 125I- tPA (5-30 μg 125I-tPA/cm2). Upon exposure to human plasma, the amount of 125I-tPA bound to the surface shows an initial drop during the first hour of incubation, followed by a slower, roughly exponential release with a t½ of appoximately 75 hours. Prostheses containing bound tPA show fibrinolytic activity as measured both by lysis of clots formed in vitro, and by hydrolysis of a synthetic polypeptide substrate. Prior to incubation in plasma, tPA bound to a polymer surface has an enzymic activity similar, if not identical to that of the native enzyme in buffered solution. However, exposure to plasma causes a decrease in the fibrinolytic activity of both bound tPA and enzyme released from the surface of the polymer. These data demonstrate that surfactant-treated prostheses can bind tPA, and that these chemically modified devices can act as a slow-release drug delivery system with the potential for reducing prosthesis-induced thromboembolism.


2012 ◽  
pp. 141208072802005
Author(s):  
Fabiano Ribeiro Cirano ◽  
ADRIANE TOGASHI ◽  
MARCIA MARQUES ◽  
FRANCISCO PUSTIGLIONI ◽  
LUIZ LIMA

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