Search results for "NATAS"
showing 10 items of 159 documents
Surface Chemistry Directs the Tunable Assembly of TiO 2 Anatase Nanocubes into Three‐Dimensional Mesocrystals
2019
Sabiedrību uzvedība pieaugot saimnieciska darbības veicēju nodokļu noslodzei
2022
Pēc nodokļu slodzes pieauguma saimnieciskās darbības veicējiem sabiedrība ir neapmierināta ar situāciju, jo uzskata ka notiek neefektīva nodokļu palielināšana, lielāka daļa pašnodarbināto personu pārtrauc oficiālo saimniecisko darbību un palielina ēnu ekonomikas līmeni. Šīs darbs ar aptaujas palīdzību un valsts ekonomisko radītāju analīzi noskaidro patiesus apstākļus Latvijā. Tā pat tika noskaidrots, ka pašnodarbinātas personas apzinās, lieto un novērtē valsts pakalpojumus, kas tiek finansēti no nodokļiem. Pētījuma rezultāts noved pie secinājuma, ka palielinot efektīvi nodokļus un piedāvājot sabiedrībai sociālo aprūpi, brīvību un iespēju attīstīties palielinās sabiedrības laimes līmenis. Sa…
Photocatalytic Degradation of 4-Nitrophenol in Aqueous Suspension by Using Polycrystalline TiO2 Impregnated with Lanthanide Double-Decker Phthalocyan…
2007
The photocatalytic activity of polycrystalline TiO2 samples impregnated with rare-earth-metal diphthalocyanines was investigated. The 4-nitrophenol (4-NP) photocatalytic degradation in aqueous suspension was used as a probe reaction. Commercial anatase TiO2 was impregnated with home-prepared double-decker phthalocyanine complexes of the lanthanide metals, such as Ce, Pr, Nd, Sm, Ho, and Gd. In particular, the impregnation with Ho, Sm, and Nd complexes, acting as sensitizers, proved beneficial for the photoactivity of the studied systems. Significant improvements of the TiO2-based catalytic system appeared possible in terms of lower impregnation loading, enhanced photoreactivity under solar …
Photocatalytic activity of nano and microcrystalline TiO2 hybrid systems involving phthalocyanine or porphyrin sensitizers
2011
Hybrid photocatalysts based on TiO(2)-anatase matrix, representing the both micro- and nano-structures, impregnated with selected lanthanide diphthalocyanine and metalloporphyrin sensitizers, were compared to evaluate their activity and effectiveness in a water suspension catalytic system designed to degrade 4-nitrophenol (4-NP) in a UV-stimulated reaction. Either type of the anatase catalyst was proved to be effective in mineralizing of 4-NP. However, kinetic studies confirmed that the composite's efficiency basically depends on the nature of the macromolecular sensitizer and to a minor extent on the dimensions (micro/nano) of the TiO(2) particles. The apparent higher activity observed for…
Influence of sol counter-ions on the visible light induced photocatalytic behaviour of TiO2 nanoparticles
2014
Titanium dioxide (TiO2) nanoparticles are attracting increasing interest because of their superior photocatalytic and antibacterial properties. Here, aqueous titanium oxy-hydroxide sols were made, using a green synthesis method, from the controlled hydrolysis/peptisation of titanium isopropoxide. Three different mineral acids were used to peptise the sol (HNO3, HBr and HCl), and provide counter-ions. The influence of nitrate or halide sol counter-ions on size distributions of the starting sols were measured via photon correlation spectroscopy (PCS). Semi-quantitative phase composition analysis (QPA), on the gels thermally treated at 450 and 600 degrees C, was carried out via Rietveld refine…
Heterogeneous Photocatalysis and Photoelectrocatalysis: From Unselective Abatement of Noxious Species to Selective Production of High-Value Chemicals
2015
Heterogeneous photocatalysis and photoelectrocatalysis have been considered as oxidation technologies to abate unselectively noxious species. This article focuses instead on the utilization of these methods for selective syntheses of organic molecules. Some promising reactions have been reported in the presence of various TiO2 samples and the important role played by the amorphous phase has been discussed. The low solubility of most of the organic compounds in water limits the utilization of photocatalysis. Dimethyl carbonate has been proposed as an alternative green organic solvent. The recovery of the products by coupling photocatalysis with pervaporation membrane technology seems to be a…
The role of water in the photocatalytic degradation of acetonitrile and toluene in gas-solid and liquid-solid regimes
2006
Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercialTiO2samples (Merck and Degussa P25). The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and degradation rate of two probe molecules. In gas-solid regime, the reacting mixture consisted of toluene or acetonitrile, oxygen, nitrogen, and water vapour. The main degradation product of toluene wasCO2with small amounts of benzaldehyde. In the presence of water vapour, the activity ofTiO2Merck remained stable but greatly decreased if water was absent.TiO2Degussa P25 continuously deactivated, even …
Influence of platinum on catalytic activity of polycrystalline WO3 employed for phenol photodegradation in aqueous suspension
1998
Abstract A series of polycrystalline WO3 solids loaded with platinum (0.5; 1.0; 2.0 and 3.0 wt%) were prepared and characterised by X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, specific surface areas determination, X-ray photoelectron spectroscopy. XPS and X-ray results indicate that the samples loaded with Pt up to 1 wt% contained on the surface mainly Pt(2+) species, while those loaded with higher amounts contained Pt(0). Moreover, the samples were employed for a probe reaction, i.e. phenol photooxidation in aqueous suspension, and their photoactivity was compared with that of two TiO2 commercial samples, mainly in the anatase phase. All the Pt–WO3 sa…
Identification of molecular pathophysiological mechanisms of non-alcoholic fatty liver disease (NAFLD)
2018
Alkohola neizraisītā taukaino aknu slimība (NATAS) ietver plaša spektra izmaiņas aknās: no pārmērīgas tauku uzkrāšanās līdz pat cirozei. NATAS ģenētiskās komponentes noteikšanai tika veikta visa genoma asociāciju pētījumus (GWAS). Polimorfismi Pnpla3 (I148M; rs738409) un Tm6sf2 (E167K; rs58542926) gēnos ir asociēti ar paaugstinātu lipīdu uzkrāšanos aknās. PNPLA3 I148M varianta proteīns pastiprināti uzkrājas uz šūnu tauku lodīšu virsmas, kas traucē tauku lodīšu normālu funkciju. Proteīna TM6SF2 167K variants izraisa proteīna nestabilitāti un ātrāku tā degradāciju. Tālākie pētījumi parāda, ka TM6SF2 ir saistīts ar aknu ļoti zema blīvuma lipoproteīnu (VLDL) veidošanu vai ekskrēciju. Izpratne p…
Time-Dependent Density Functional Theory Calculations of N- and S-Doped TiO2 Nanotube for Water-Splitting Applications
2021
This research was funded by the Latvian Council of Science grant LZP-2018/2-0083. Institute of Solid State Physics, University of Latvia, as the Center of Excellence, has received funding from the European Union?s Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under Grant Agreement No. 739508, project CAMART2.