Search results for "vanA"
showing 10 items of 345 documents
Role of magnesium in insulin action, diabetes and cardio-metabolic syndrome X
2003
Magnesium (Mg) is one of the most abundant ions present in living cells and its plasma concentration is remarkably constant in healthy subjects. Plasma and intracellular Mg concentrations are tightly regulated by several factors. Among them, insulin seems to be one of the most important. In vitro and in vivo studies have demonstrated that insulin may modulate the shift of Mg from extracellular to intracellular space. Intracellular Mg concentration has also been shown to be effective in modulating insulin action (mainly oxidative glucose metabolism), offset calcium-related excitation-contraction coupling, and decrease smooth cell responsiveness to depolarizing stimuli. A poor intracellular M…
Correction: One-pot synthesis of a new generation of hybrid bisphosphonate polyoxometalate gold nanoparticles as antibiofilm agents
2019
A reduced polyoxovanadate functionalized with bisphosphonate molecules was synthesized and used to prepare in one step hybrid organic–inorganic polyoxometalate decorated gold nanoparticles. These new composites were shown to strongly inhibit P. aeruginosa and S. epidermidis biofilm growth, with the three components constituting the nanoparticles (Au0 core, vanadium and alendronate) acting synergistically.
Fundamental limits for transmission modulation in VO2 metasurfaces
2022
The interest in dynamic modulation of light by ultra-thin materials exhibiting insulator–metal phase transition, such as VO 2 , has rapidly grown due to the myriad industrial applications, including smart windows and optical limiters. However, for applications in the telecommunication spectral band, the light modulation through a thin VO 2 film is low due to the presence of strong material loss. Here, we demonstrate tailored nanostructuring of VO 2 to dramatically enhance its transmission modulation, reaching a value as high as 0.73, which is 2 times larger than the previous modulation achieved. The resulting designs, including free-topology optimization, demonstrate the fundamental limit i…
Vistu vanaga (Accipiter gentilis L.) konstatēšanas iespējamība Latvijā: divu metožu salīdzinājums un atsevišķu ietekmējošo faktoru analīze
2016
Darba mērķis ir noskaidrot vistu vanaga teritoriālo saucienu atskaņošanas ietekmi uz sugas ligzdošanas iecirkņu konstatēšanu, to salīdzinot ar Eiropā pieņemto vizuālo uzskaišu metodi un skaidrot konstatējamības izmaiņas saistībā ar attālumu no ligzdas, ligzdošanas stadijām, kalendāro un diennakts laiku. Noskaidrots, ka vistu vanaga konstatēšanas iespējamību ievērojami palielina akustiskā stimulēšana, izmantojot tēviņa teritoriālo saucienu ierakstu. Visās fenoloģiskajās fāzēs, izņemot ligzdu atstājušus mazuļus, konstatēšanas iespējamība ir augstāka izmantojot provocēšanu. Augstākā vistu vanaga konstatēšanas iespējamība ir līdz 200 m attālumam no ligzdas laikā līdz 100 dienai kopš gada sākuma…
Copolymerization of ethylene with higher 1-olefins over vanadium catalyst supported on Al(i-Bu)3 modified magnesium carrier
2008
Badano proces kopolimeryzacji etylenu z wyższymi 1-olefinami (C6-C12) wobec katalizatora wanadowego (VOCl3) immobilizowanego na nośniku magnezowym MgCl2 (THF) 2 modyfikowanym z zastosowaniem Al(i-Bu) 3. W charakterze aktywatora nośnikowego prekatalizatora wanadowego zastosowano Et2AlCl. Stwierdzono, że aktywność takiego układu katalitycznego jest porównywalna z aktywnością katalizatora z prekursorem wanadowym osadzonym na niemodyfikowanym nośniku magnezowym. Zaobserwowano także, że wprowadzenie komonomeru do środowiska reakcji powoduje niewielkie zmniejszenie wydajności procesu w porównaniu z homopolimeryzacją etylenu, postępującą w miarę wzrostu stężenia komonomeru w środowisku reakcji. Do…
Gustava Vanaga darba galds
2021
Par godu ķīmiķa organiķa Gustava Vanaga (1891-1965) 130. dzimšanas gada dienai izveidota virtuālā izstāde "Gustava Vanaga darba galds", kurā attēlots profesora Vanaga memoriālais darba galds Latvijas Ķīmijas vēstures muzejā Rīgā, Kronvalda bulvārī 4 un uz tā izvietotie objekti - piemiņas albumi, darbinieka un studenta apliecības, laboratorijas žurnāls, sekmju grāmatiņa, piezīmju lapiņas, jubilejās saņemtās dāvanas no studentiem un kolēģiem u.c. piemiņas lietas.
Structural and electronic elucidation of a N-heterocyclic silylene vanadocene adduct
2017
The solid and solution state structure of the vanadium(II) N‐ heterocyclic silylene (NHSi) complex, [(SiIPr)V(Cp)2] (1) is reported ( SiIPr: 1,3‐bis(2,6‐diisopropylphenyl)‐1,3‐diaza‐2‐silacyclopent‐4‐ en‐2‐ylidene). The electronic structure of 1 is probed using combination of magnetic measurements, EPR spectroscopy and computational studies. The V–Si bond strength and complex forming mechanism between vanadocene and NHSi ligand is elucidated using computational methods. peerReviewed
Naturally Occurring Oxazole Structural Units as Ligands of Vanadium Catalysts for Ethylene-Norbornene (Co)polymerization
2021
1,3-Oxazole and 4,5-dihydro-1,3-oxazole are common structural motifs in naturally occurring peptides. A series of vanadium complexes were synthesized using VCl3(THF)3 and methyl substituted (4,5-dihydro-1,3-oxazol-2-yl)-1,3-oxazoles as ligands and analyzed using NMR and MS methods. The complexes were found to be active catalysts both in ethylene polymerization and ethylene-norbornene copolymerization. The position of methyl substituent in the ligand has considerable impact on the performance of (co)polymerization reaction, as well as on the microstructure, and thus physical properties of the obtained copolymers.
Titanium and Vanadium Catalysts with 2-Hydroxyphenyloxazoline and Oxazine Ligands for Ethylene-Norbornene (co)Polymerization
2019
A series of titanium and vanadium complexes with oxazoline 2-(4,5-dihydro-1,3-oxazol-2-yl)phenol (L1), 2-(4-methyl-4,5-dihydro-1,3-oxazol-2-yl)phenol (L2), and oxazine 2-(5,6-dihydro-4H-1,3-oxazin-2-yl)phenol (L3) ligands were synthesized, and their structures were determined by NMR and MS methods as (L)2MtCl2. The vanadium complexes were found to be highly active in ethylene (7300 kgPE/(molV·
Transition metal complexes of tetradentate and bidentate Schiff bases as catalysts for ethylene polymerization: Effect of transition metal and cocata…
2009
This article compares catalytic performance of ethylene polymerization in similar polymerization conditions of transition metal complexes having two ligands [O,N] (phenoxy-imine) and having one tetradentate ligand [O,N,N,O] (salphen or salen). It is shown that the activity of both complex types as well as the product properties depend in the same way on the type of central metal in the complex and on the cocatalyst used. Although the type of ligand has some effect on the catalyst activity, yet it does not control the properties of the obtained products. The vanadium and zirconium complexes, irrespective of the cocatalyst used, yield linear polyethylene with high molecular weight (a few hund…