Search results for "DOTS"
showing 10 items of 181 documents
Pārdabiskais Hērodota “Vēsturē” kā vēsturisko procesu skaidrošanas līdzeklis
2017
Pārdabiskais Hērodota “Vēsturē” kā vēsturisko procesu skaidrošanas līdzeklis. Vītoliņš R.R., zinātniskais vadītājs dr. hist. Tumans H. Bakalaura darbs, 57. lpp. Latviešu valodā. Darbā pētīts kā dievu vara un tās izpausmes tiek saprastas Hērodota darbā un izmantotas, lai skaidrotu vēstures procesu virzību. Šeit īpaši vērts minēt skaidrojumus, kas nodoti caur sapņiem un orākuliem, kā arī vispārējus līdzsvara principus, kuru pārkāpšana ļauj skaidrot notikumu attīstības gaitu un reaģēt uz laikmetīgajām norisēm Hērodota dzīves laikā.
Persijas impērija un kultūrainavas Hērodota "Vēsturē"
2019
Persijas impērija un kultūrainavas Hērodota "Vēsturē", Vītoliņš, R. R. zinātniskais vadītājs dr. hist. Tumans, H. Maģistra darbs, 97. lpp. Latviešu valodā. Maģistra darbā pētīts kā tiek veidotas atšķirības starp Persiju un zemēm, kuras tā mēģina iekarot Hērodota “Vēstures” naratīvā. Kultūrainava pētīta kā elements, kurā integrētas simboliskas nozīmes, kas to padara par būtisku naratīva sastāvdaļu.
Bio serves nano: biological light-harvesting complex as energy donor for semiconductor quantum dots.
2012
Light-harvesting complex (LHCII) of the photosynthetic apparatus in plants is attached to type-II core-shell CdTe/CdSe/ZnS nanocrystals (quantum dots, QD) exhibiting an absorption band at 710 nm and carrying a dihydrolipoic acid coating for water solubility. LHCII stays functional upon binding to the QD surface and enhances the light utilization of the QDs significantly, similar to its light-harvesting function in photosynthesis. Electronic excitation energy transfer of about 50% efficiency is shown by donor (LHCII) fluorescence quenching as well as sensitized acceptor (QD) emission and corroborated by time-resolved fluorescence measurements. The energy transfer efficiency is commensurable …
Dual Cherenkov Radiation-Induced Near-Infrared Luminescence Imaging and Photodynamic Therapy toward Tumor Resection
2020
International audience; Cherenkov radiation (CR), the blue light seen in nuclear reactors, is emitted by some radiopharmaceuticals. This study showed that (1) a portion of CR could be transferred in the region of the optical spectrum, where biological tissues are most transparent: as a result, upon radiance amplification in the near-infrared window, the detection of light could occur twice deeper in tissues than during classical Cherenkov luminescence imaging and (2) Cherenkov-photodynamic therapy (CR-PDT) on cells could be achieved under conditions mimicking unlimited depth using the CR-embarked light source, which is unlike standard PDT, where light penetration depth is limited in biologi…
The effect of high-In content capping layers on low-density bimodal-sized InAs quantum dots
2013
[EN] The structural and morphological features of bimodal-sized InAs/(In) GaAs quantum dots with density in the low 10(9) cm(-2) range were analyzed with transmission electron microscopy and atomic force microscopy and were related to their optical properties, investigated with photoluminescence and time-resolved photoluminescence. We show that only the family of small quantum dots (QDs) is able to emit narrow photoluminescence peaks characteristic of single-QD spectra; while the behavior of large QDs is attributed to large strain fields that may induce defects affecting their optical properties, decreasing the optical intensity and broadening the homogeneous linewidth. Then, by using a rat…
Tunable light emission by exciplex state formation between hybrid halide perovskite and core/shell quantum dots: Implications in advanced LEDs and ph…
2016
A perovskite–quantum dot exciplex has been detected, opening a broad range of possibilities for advanced optoelectronic devices.
Skolēnu caurviju kompetenču veidošanās matemātikā 1.klasē
2021
Ievadā ir raksturota problēma un pētījuma aktualitāte. Ir izstrādātas zinātniskās kategorijas. Šī pētījuma mērķis bija pamatot skolēnu caurviju kompetenču veidošanos matemātikā 1. klasē. Mērķa sasniegšanai tika izvirzīta hipotēze, uzdevumi, metodes un pētījuma bāze. Darba pirmajā nodaļā tika analizēta literatūra par caurviju kompetencēm matemātikā, matemātikas saturu un mācību procesa organizēšanu, kā arī aplūkotas dažādu autoru taksonomijas, kā mācīšanās veida izvēle, lai veicinātu caurviju kompetenču veidošanos. Pamatojoties uz analizēto literatūru, darba autore izstrādāja kritērijus un rādītājus, lai veiktu pētījumu un varētu novērtēt skolēnu caurviju prasmes matemātikā. Darba otrajā nod…
The effect of surface charge on nonspecific uptake and cytotoxicity of CdSe/ZnS core/shell quantum dots
2015
In this work, cytotoxicity and cellular impedance response was compared for CdSe/ZnS core/shell quantum dots (QDs) with positively charged cysteamine–QDs, negatively charged dihydrolipoic acid–QDs and zwitterionic D-penicillamine–QDs exposed to canine kidney MDCKII cells. Pretreatment of cells with pharmacological inhibitors suggested that the uptake of nanoparticles was largely due to receptor-independent pathways or spontaneous entry for carboxylated and zwitterionic QDs, while for amine-functionalized particles involvement of cholesterol-enriched membrane domains is conceivable. Cysteamine–QDs were found to be the least cytotoxic, while D-penicillamine–QDs reduced the mitochondrial activ…
Comparative evaluation of the impact on endothelial cells induced by different nanoparticle structures and functionalization
2015
In the research field of nanoparticles, many studies demonstrated a high impact of the shape, size and surface charge, which is determined by the functionalization, of nanoparticles on cell viability and internalization into cells. This work focused on the comparison of three different nanoparticle types to give a better insight into general rules determining the biocompatibility of gold, Janus and semiconductor (quantum dot) nanoparticles. Endothelial cells were subject of this study, since blood is the first barrier after intravenous nanoparticle application. In particular, stronger effects on the viability of endothelial cells were found for nanoparticles with an elongated shape in compa…
Water-dispersed semiconductor nanoplatelets with high fluorescence brightness, chemical and colloidal stability
2019
Quasi-two dimensional semiconductor nanoplatelets (NPLs) exhibit high spectral brightness and large absorption cross sections, making them promising for various applications including bioimaging. However, the synthesis of NPLs takes place in organic solvents, therefore they require phase transfer in order to use them in aqueous environments. The phase transfer of NPLs has so far been challenging with few examples in literature. This is likely due to the facile agglomeration of materials with plate-like geometries during the coating procedure. Here we demonstrate how to overcome agglomeration and transfer NPLs, individually coated with amphiphilic polymer chains, to aqueous phase. Upon one a…