Search results for "IOLs"

Stereoselective synthesis and application of tridentate aminodiols derived from (+)-pulegone

2016

Abstract A library of tridentate aminodiols, derived from naturally occurring (R)-(+)-pulegone, was synthesized and applied as chiral catalysts in the addition of diethylzinc to benzaldehyde. The reduction of pulegone furnished pulegol, which was transformed into allylic trichloroacetamide via Overman rearrangement of the corresponding trichloroacetimidate. The protected enamine was subjected to dihydroxylation with OsO4/NMO system resulting in a 1:1 mixture of (1R,2R,4R)- and (1S,2S,4R)-aminodiol diastereomers. After the removal of the trichloroacetyl protecting groups, the obtained primary aminodiols were transformed into secondary ones. The regioselectivity of the ring closure of the N-b…

Dažādu katalizatoru ietekme uz tallu eļļas poliolu sintēzi

2016

Dažādu katalizatoru ietekme uz tallu eļļas poliolu sintēzi. Seržāne L., darba vadītāji Dr.Chem.Prof. Actiņš A., Dr.Sc.Ing. Cābulis U., Maģistra darbs, 74 lappuses, 53 attēli, 7 tabulas, 47 literatūras avoti. Latviešu valodā. Darba literatūras daļā ir dots informācijas ieskats poliuretānu ķīmijā. Veikts apskats par polioliem, kas iegūti gan no naftas pārstrādes produktiem, gan no atjaunojamām izejvielām un aprakstīti poliolus raksturojošie lielumi. Teorētisks apskats veikts par tallu eļļu, tās iegūšanu un sastāvu, aprakstīta poliolu sintēze no tallu eļļas un to galveno parametru – skābes skaitļa un hidroksilskaitļa – noteikšanas metodes. Literatūras apskatā aprakstīta katalīze un darbā izman…

Full inhibition of enzymatic browning in the presence of thiol-functionalised silica nanomaterial

2018

[EN] Darkening processed fruits and vegetables is caused mainly by enzymatic browning through polyphenol oxidase (PPO) action. Accordingly, we explored the potential of four silica-based materials (MCM-41 nanometric size, MCM-41 micrometric size, UVM-7 and aerosil), non-functionalised and functionalised with thiol groups, to inhibit PPO activity in the model system and apple juice. All materials showed relevant performance when immobilising and inhibiting PPO in model systems, and support topology is a main factor for enzyme immobilisation and inhibition. Thiol-containing silica UVM7-SH showed the greatest inactivation, and similar browning values to those obtained by acidification. The enz…

Nanoencapsulation in Lipid-Core Nanocapsules Controls Mometasone Furoate Skin Permeability Rate and Its Penetration to the Deeper Skin Layers

2013

<b><i>Aims:</i></b> The influence of nanoencapsulation of mometasone furoate (MF) in poly(ε-caprolactone) lipid-core nanocapsules (LNC) on its in vitro human skin permeation and penetration was evaluated. <b><i>Methods:</i></b> Semisolid formulations were prepared by increasing the viscosity of LNC using a carbomer (Carbopol® Ultrez at 0.5% w/v). Two complementary techniques (the static Franz diffusion cell model and the Saarbrücken penetration model) were used to evaluate skin permeation/penetration. <b><i>Results:</i></b> The drug release rate was decreased by nanoencapsulation. The skin permeability of MF was control…

Evaluation of the performance of multifocal intraocular lenses image quality: analysis of the standard methods

2007

Purpose: To analyze the standard methods used to describe intraocular lenses (IOL) and to suggest some improvements to make them applicable for multifocal IOLs. Methods: The EN-ISO standards and the standards of the American National Standards Institute (ANSI) for the evaluation of the performance of IOLs are tested for multifocal IOLs. The MTF of the one refractive multifocal IOL and two hybrid refractive-diffractive multifocal IOLs is measured for both distance focus and near focus and using different pupil sizes. Results: The average modulation (AM) from 0 to 100 c/mm of multifocal IOLs (for the distance focus) is about 40-50% lower than the AM of monofocal IOLs, for all pupil sizes stud…

PEG-based Multifunctional Polyethers with Highly Reactive Vinyl-Ether Side Chains for Click-Type Functionalization

2011

Introduction of highly reactive vinyl ether moieties along a poly(ethylene-glycol) (PEG) backbone has been realized by copolymerization of the novel epoxide monomer ethoxy vinyl glycidyl ether (EVGE) with ethylene oxide (EO). A series of copolymers with varying structure (block and random) as well as EVGE comonomer content (5-100%) with molecular weights in the range of 3,900-13,200 g/mol and narrow molecular weight distributions (M-w/M-n = 1.06-1.20) has been synthesized and characterized with respect to their microstructure and thermal properties. The facile transformation of the vinyl ether side chains in click type reactions was verified by two different post polymerization modification…

Lenti intraoculari filtranti

2015

Relazione e stato dell'arte sulle lenti intraoculari filtranti

ACUITA’ VISIVA, PERFORMANCE DI LETTURA, QUALITA’ DELLA VITA E SENSIBILITA’ AL CONTRASTO SOGGETTIVA ED ELETTROFUNZIONALE IN PAZIENTI AFFETTI DA CATARA…

Perceived minerality in sauvignon blanc wine: chemical reality or cultural construct?

2016

International audience; The study aimed to determine the relationship between perceived mineral character in wine and wine chemical composition. We investigated the sensory properties and chemical composition of sauvignon blanc wines from two major sauvignon-producing countries, New Zealand and France. Sensory experiments employing 16 wines (8 French, 8 New Zealand) were conducted in Marlborough, New Zealand and in three regions of France, namely Bordeaux, Burgundy, and the Sancerre/Loire region. Wine professionals (31 New Zealanders and 32 French professionals) sensorially characterised the 16 wines under three conditions, bouquet only (ortho-nasal olfaction), palate only (nose clip condit…

Selection of probiotic strains and improving the survival and functionality of an academic strain, Bifidobacterium bifidum, by changing the redox pot…

2012

The aim of this work was to select rationally a probiotic strain by setting up a screening method as well as study and understand the impact of the redox potential (Eh) and gas bubbling on the survival of Bifidobacterium bifidum in a fermented dairy product. In a first time, we have developed selection techniques of probiotic bacteria on the criteria of viability / vitality (flow cytometry analysis) and on the criteria of functionality (antioxidant). We were able to select strains of industrial interest as well as an academic strain, Bifidobacterium bifidum.Secondly, we have studied effect of modifying redox potential by gas bubbling on the survival of B. bifidum in a fermented dairy produc…