Search results for " Stab"

Corrigendum to “Polysorbate 80 controls Morphology, structure and stability of human insulin Amyloid-Like spherulites” [J. Colloid Interface Sci. 606…

2023

o-Phthalaldehyde–N-acetylcysteine polyamine derivatives: formation and stability in solution and in C18 supports

2001

A comparative study of different derivatization procedures has been performed in order to improve the stability of the reaction products o-phthalaldehyde-N-acetylcysteine (OPA-NAC) polyamines. Procedures such as solution derivatization, solution derivatization followed by retention on a packing support, derivatization on different packing supports and on-column derivatization, have been optimized and compared. The degradation rate constant (k) of the derivative was dependent on the procedure used and on the analyte. For the spermine (the most unstable isoindol tested) k was 8 +/- 2 x 10(-2) min(-1) in solution versus 7.7 +/- 1.1 x 10(-4) min(-1) on the (C18) solid support. The results obtai…

An investigation of the stability of free and glucuronidated 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid in authentic urine samples.

2004

Preanalytical stability of a drug and its major metabolites is an important consideration in pharmacokinetic studies or whenever the analyte pattern is used to estimate drug habits. Firstly, the stability of free and glucuronidated 11-nor-delta9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH, THCCOOglu) in authentic urine samples was investigated. Random urine samples of cannabis users (n = 38) were stored at -20, 4, and 20 degrees C up to 15 days and up to 5 days at 40 degrees C, and alterations of the analyte pattern during storage were followed by liquid chromatography-tandem mass spectrometry. Secondly, the influence of pH (range 5.0-8.0) on the stability of the analytes was studied us…

Understanding the role of Ti-rich domains in the stabilization of gold nanoparticles on mesoporous silica-based catalysts

2018

3 Tablae, 14 Figures.-- Supplementary material.-- © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

Informatīvā paneļa "InfoDesk" izstrāde

2015

Darbā ir aprakstīts slīdrādes rīka „InfoDesk” funkcionalitātes paplašināšana, atkļūdojot un papildinot to. „InfoDesk” nodrošina slaidu veidošanu, konfigurējamību un slīdrādi uz Android ierīcēm ar API līmeni 14 vai augstāk. Pirms kvalifikācijas darbā aprakstītajām izmaiņām „InfoDesk” spēja izveidot slaidus, tos atskaņot, kā arī konfigurēt tos, bet katrā no šīm darbībām programma varēja pātraukt darboties. „InfoDesk” klāt pievienotā funkcionalitātē ietilpst plašāka slaidā pievienoto elementu kontrole, saglabāšana uz ārējas atmiņas ierīces, labāka atmiņas lietošana, vispārēja programmatūras stabilitāte. Sistēma realizēta Java programmēšanas valodā, izstrādes vidēs Eclipse un Android Studio.

Ag5 nanoclusters with dual catalytic antiradical activities

2022

Silver nanoclusters of five atoms (Ag5) display outstanding catalytic activities for the deactivation of radicals. Using 2,2-diphenyl-1‑picrylhydrazyl (DPPH) radical as a model system, we observed a fast radical reduction to DPPH anions using only [Ag5] 3 to 4 orders of magnitude less than [DPPH]. Moreover, nanoclusters remain stable at the end of the reaction, and can deactivate again DPPH radicals at the same rate, indicating that they act as anti-radical catalysts. The radical scavenger catalytic activity of Ag5 proceeds selectively through the oxidation of methanol (used to dissolve the radical) to formaldehyde, which is supported by DFT calculations. The obtained catalytic rate constan…

Role of the Non-Canonical RNAi Pathway in the Antifungal Resistance and Virulence of Mucorales

2021

Mucorales are the causal agents for the lethal disease known as mucormycosis. Mortality rates of mucormycosis can reach up to 90%, due to the mucoralean antifungal drug resistance and the lack of effective therapies. A concerning urgency among the medical and scientific community claims to find targets for the development of new treatments. Here, we reviewed different studies describing the role and machinery of a novel non-canonical RNAi pathway (NCRIP) only conserved in Mucorales. Its non-canonical features are the independence of Dicer and Argonaute proteins. Conversely, NCRIP relies on RNA-dependent RNA Polymerases (RdRP) and an atypical ribonuclease III (RNase III). NCRIP regulates the…

Unveiling the oxidation behavior of liquid-phase exfoliated antimony nanosheets

2020

Abstract Antimonene, a monolayer of β-antimony, is increasingly attracting considerable attention, more than that of other monoelemental two-dimensional materials, due to its intriguing physical and chemical properties. Under ambient conditions, antimonene exhibits a high thermodynamic stability and good structural integrity. Some theoretical calculations predicted that antimonene would have a high oxidation tendency. However, it remains poorly investigated from the experimental point of view. In this work, we study the oxidation behavior of antimonene nanosheets (ANS) prepared by ultrasonication-assisted liquid-phase exfoliation. Using a set of forefront analytical techniques, a clear effe…

Oxidative stability of virgin olive oils

2001

An investigation was carried out on virgin olive oils of the Gentile (Larino), Gentile (Colletorto), Coratina, and Leccino varieties, harvested at different times, to assess their oxidation stability. The olive oils were analyzed by means of peroxide, K-232, and K 270 values at 1, 6, 12, and 18 mon of storage in green bottles, in the dark, at temperatures ranging from a mean of 6degreesC in winter to 12degreesC in summer. A subsample was also oven-tested at 75degreesC and then analyzed on a weekly basis using the same oxidative parameters. The less ripe the olives (harvested in the same area, during 1 mon), the more resistant the olive oils were to forced oxidation. The amount of total phen…

Delivery of liquorice extract by liposomes and hyalurosomes to protect the skin against oxidative stress injuries.

2015

Liquorice extract, obtained by percolation in ethanol of Glycyrrhiza glabra L. roots, was incorporated in liposomes and hyalurosomes, new phospholipid-sodium hyaluronate vesicles, and their protective effect against oxidative stress skin damages was probed. As a comparison, raw glycyrrhizin was also tested. All the vesicles were small in size (≤ 100 nm), with a highly negative zeta potential ensuring long-term stability, and able to incorporate a high amount of the extract. In vitro tests showed that the liquorice extract loaded in vesicles was able to scavenge DPPH free radical (80% inhibition) and to protect 3T3 fibroblasts against H2O2-induced oxidative stress, restoring the normal condi…