Search results for "actions"

Antibacterial Activity of Positively and Negatively Charged Hematite (α-Fe2O3) Nanoparticles to Escherichia coli, Staphylococcus aureus and Vibrio fi…

2021

This research and work has been supported by the European Regional Development Fund within the Activity 1.1.1.2 “Post-doctoral Research Aid” of the Specific Aid Objective 1.1.1 (i.e., “to increase the research and innovative capacity of scientific institutions of Latvia and the ability to attract external financing, investing in human resources and infrastructure”) of the Operational Programme “Growth and Employment” (No. 1.1.1.2/VIAA/2/18/331).

UV-VISIBLE LUMINESCENCE OF SILICA NANOPARTICLES

Thiophene based imino-pyridyl palladium(II) complexes : Synthesis, molecular structures and Heck coupling reactions

2017

The new compounds (5-methyl-2-thiophene-2-pyridyl(R))imine [R = methyl (L1); R = ethyl (L2)] and (5-bromo-2-thiophene-2-pyridyl(R)imine [R = methyl (L3); R = ethyl (L4)] were successfully synthesized via Schiff base condensation reaction and obtained in good yields. These potential ligands were reacted with [PdCl2(COD)] and [PdClMe(COD)] to give the corresponding complexes [PdCl2(L)] (L = L1-L4; 1–4) and [PdClMe(L)] (L = L1-L4; 5–8). All compounds were characterized by IR, 1H and 13C NMR spectroscopy, elemental analysis and mass spectrometry. The molecular structures of 1, 2, 6 and 8 were confirmed by X-ray crystallography. The complexes were evaluated as catalyst precursors for standard He…

Organocatalytic Oxa-Michael/Michael/Michael/Aldol Condensation Quadruple Domino Sequence : Asymmetric Synthesis of Tricyclic Chromanes

2018

An efficient and highly stereoselective one-pot, four-component synthesis of functionalized tricyclic chromanes has been achieved through an organocatalyzed quadruple domino reaction. The reaction sequence involves an oxa-Michael/Michael/Michael/aldol condensation between alcohols, 2 equiv of acrolein, and nitrochromenes to generate the pharmaceutically important tricyclic chromanes bearing three contiguous stereogenic centers including a chiral tetrasubstituted carbon center in good domino yields (30–70%) and excellent diastereo- and enantioselectivities (>20:1 dr and >99% ee). peerReviewed

Synthesis and Structure-Affinity Relationships of Spirocyclic Benzopyrans with Exocyclic Amino Moiety

2019

σ1 and/or σ2 receptors play a crucial role in pathological conditions such as pain, neurodegenerative disorders, and cancer. A set of spirocyclic cyclohexanes with diverse O-heterocycles and amino moieties (general structure III) was prepared and pharmacologically evaluated. In structure-activity relationships studies, the σ1 receptor affinity and σ1:σ2 selectivity were correlated with the stereochemistry, the kind and substitution pattern of the O-heterocycle, and the substituents at the exocyclic amino moiety. cis-configured 2-benzopyran cis-11b bearing a methoxy group and a tertiary cyclohexylmethylamino moiety showed the highest σ1 affinity ( Ki = 1.9 nM) of this series of compounds. In…

Adsorption and Activation of Water on Cuboctahedral Rhodium and Platinum Nanoparticles

2017

Rh and Pt are widely used as the components in heterogeneous catalysts for multiple industrial applications. Because the metals are typically in the form of nanoparticles in real catalysts, it is important to carefully select models for the computational prediction of the catalytic properties. Here we report a first-principles study on the water activation, an important step in numerous catalytic reactions, using the finite-size Rh and Pt nanoparticle models and compare them to the extended surface models. We show that regardless of the model, adsorption and activation of water is practically identical for both metals, whereas the dissociation is energetically more favorable on Rh. The expe…

The challenges of GxE research: A rejoinder

2017

The question of Organic Unity in Flavour: The whole is not equal to the sum of the parts

2021

International audience

Branching Ratios and Spectral Functions of $\tau$ Decays: final ALEPH measurements and physics implications

2005

The full LEP-1 data set collected with the ALEPH detector at the $Z$ pole during 1991-1995 is analysed in order to measure the $\tau$ decay branching fractions. Extensive systematic studies are performed, in order to match the large statistics of the data sample corresponding to over 300 000 measured and identified $\tau$ decays. Branching fractions are obtained for the two leptonic channels and eleven hadronic channels defined by their respective numbers of charged particles and $\pi^0$'s. Using previously published ALEPH results on final states with charged and neutral kaons, corrections are applied to the hadronic channels to derive branching ratios for exclusive final states without kao…

Ultraviolet B radiation induced alterations in immune function of fish : in relation to habitat preference and disease resistance

2009

Runsas altistuminen auringolle on tunnetusti haitallista ihmisten ja eläinten hyvinvoinnille. Eveliina Markkula tutki väitöskirjatyössään, miten ultravioletti B (UVB) -säteilylle altistuminen vaikuttaa kalojen vastustuskykyyn ja tautialttiuteen.- Ilmakehän otsonikerroksen oheneminen viime vuosikymmenten aikana on johtanut UVB-säteilyn lisääntymiseen maan pinnalla. UVB-säteily tunkeutuu myös kirkkaisiin järvi- ja merivesiin ja voi näin aiheuttaa haittaa kaloille, Markkula kertoo.UVB-säteilyn on jo aiemmin todettu lisäävän kalojen varhaisten elinvaiheiden epämuodostumia ja kuolleisuutta. Kertaluonteinenkin altistuminen lampuilla tuotetulle UVB-säteilylle aiheuttaa muutoksia kalan immuunijärje…