Search results for "Kulta"
showing 7 items of 67 documents
Photodynamics studies of ligand-protected gold nanoclusters by using ultrafast transient infrared spectroscopy
2015
Highly monodisperse samples of three ligand-protected gold nanoclusters Au102(pMBA)44, Au144(SC2H4Ph)60, and a cluster tentatively identified as Au130(pMBA)50, were characterized by UV/vis and infrared spectroscopy, and their photodynamics was studied by transient absorption spectroscopy. The dynamics study for each cluster was performed by electronically exciting the cluster with a pump pulse in the visible or near infrared region and by monitoring the transient absorption of vibrational modes of the ligands with a mid-IR probe pulse. The photodynamics studies were used to determine the molecular or metallic behavior of the cluster, and also to gain important size dependent information abo…
Towards Controlled Synthesis of Water-Soluble Gold Nanoclusters : Synthesis and Analysis
2019
Water-soluble gold nanoclusters with well-defined molecular structures and stability possess particular biophysical properties making them excellent candidates for biological applications as well as for fundamental spectroscopic studies. The currently existing synthetic protocols for atomically monodisperse thiolate-protected gold nanoclusters (AuMPCs) have been widely expanded with organothiolates, yet the direct synthesis reports for water-soluble AuMPCs are still deficient. Here, we demonstrate a wet-chemistry pH-controlled synthesis of two large water-soluble nanoclusters utilizing p-mercaptobenzoic acid (pMBA), affording different sizes of plasmonic AuMPCs on the preparative scale (∼7 …
Recombinant nanocapsid for targeted theranostic delivery
2017
Developments in diagnostic and therapeutic delivery are trending towards molecular level targeting with nano-platforms. Targeted delivery reduces generalized distribution by localizing diagnostic and/or therapeutic (theranostic) molecules to an intended target site. The first section of this thesis proposes Hepatitis E Virus (HEV) nanocapsids as a vector to stabilize and target theranostic delivery. Derived from the capsid protein of HEV, a feco-orally transmitted virus, HEV-like particles self-assemble in to non-infectious, nanocapsids that can withstand harsh protease and pH conditions in the mucosal system. The flexible nanocapsid surface protrusion domain is amenable to substantial modi…
Support work function as a descriptor and predictor for the charge and morphology of deposited Au nanoparticles
2020
We show, using density functional theory calculations, that the charge, magnetic moment, and morphology of deposited Au nanoclusters can be tuned widely by doping the oxide support with aliovalent cations and anions. As model systems, we have considered Aun (n = 1, 2, or 20) deposited on doped MgO and MgO/Mo supports. The supports have been substitutionally doped with varying concentrations θ of F, Al, N, Na, or Li. At θ = 2.78%, by varying the dopant species, we are able to tune the charge of the Au monomer between −0.84e and +0.21e, the Au dimer between −0.87e and −0.16e, and, most interestingly, Au20 between −3.97e and +0.49e. These ranges can be further extended by varying θ. These chan…
Removal of alkylthiols from gold surface : molecular dynamics simulations in density functional theory
2015
Self-assembled monolayers (SAMs) are systems of organic compounds adsorbed onto metal or silicon, forming a dense cover on top of the substrate; the most studied system of SAMs consists of alkylthiols on gold surface. In 2012, Liao et al. found out, as a side-product of their chemical lift-off lithography research, that when the thiol cover was pulled off the gold surface, a layer of gold was also removed from the substrate. In our study, this process was simulated using density functional theory (DFT) within projector augmented-wave (PAW) method to examine the dynamics at the interface of gold and the thiol cover. According to our results, acquired using the linear combination of atomic or…
Starppriekšmetu saiknes īstenošana vizuālās mākslas fakultatīvo nodarbību programmā “Bizantijas māksla” sākumskolā
2020
Skolotāja pieredzes darbā „Starppriekšmetu saiknes īstenošana vizuālās mākslas fakultatīvo nodarbību programmā „Bizantijas māksla” sākumskolā” ir apkopota un izvērtēta pieredze, kuru darba autore ir ieguvusi organizējot un vadot vizuālās mākslas fakultatīvās nodarbības „Bizantijas māksla” vienā no Rīgas mazākumtautību vidusskolām (1. – 4.klasei). Darba autores – skolotājas uzdevums ir organizēt mācību procesu tādā veidā, lai skolēni uztvertu fakultatīvo nodarbību kā daļu no kopīgā mācību procesa, sasaistot nodarbību jauno saturu ar citiem mācību priekšmetiem. Skolotāja pieredzes darba mērķis ir izpētīt starppriekšmetu saiknes īstenošanas iespējas sākumskolā fakultatīvo nodarbību programmu “…
Itsejärjestäytyvä DNA-kultananopartikkeli-rakenne yhden elektronin transistorina
2012
Tässä tutkielmassa selvitettiin kultananopartikkelien ja itsejärjestäytyvän DNA-järjestelmän soveltuvuutta nanoteknologian komponenttina. Työssä yhdistetään funktionalisoituja kultapartikkeleita jo valmiiksi tutkittuun itsejärjestäytyvään DNA-rakenteeseen työnimeltään BAB. Se muodostuu kolmen TX-tiilen ketjusta, johon suunnittelin kandidaatin tutkinnossani kiinnityskohdat kultapartikkeleille. Yhdistämällä kultapartikkelit ja BAB-rakenne saadaan muodostettua kolmen partikkelin ketju, ja tällä rakenteella pyritään muodostamaan yhden elektronin transistori: Toiminta yhden elektronin transistorina pyrittiin havainnoimaan Coulombin saarron avulla mittaamalla differentiaalista konduktanssia sekä …