Search results for "hydrogen peroxide"

Oxidative stress-driven expression of myeloperoxidase in endothelial cells results in accumulation of markers of oxidative and nitrosative stress in …

2009

Endothelial cells (ECs), are able to manage with higher concentrations of ROS as well as reactive nitrogen species, respect to the other cell types. The unbalance between oxidizing species and antioxidant cellular defences has been implicated in the pathogenesis of cardiovascular diseases. While the role of MPO in the oxidative burst is well established, the effects of this enzyme on endothelial biology have only recently come to light. MPO can interact with endothelial –derived NO causing its depletion and favouring its conversion to nitrogen dioxide radical, a compound responsible of protein nitration generating 3-nitrotyrosine. Moreover, MPO is the only enzyme capable to form hypoclorous…

Wearable sensor for real-time monitoring of oxidative stress

Tonometers and infectious risk: myth or reality? Efficacy of different disinfection regimens on tonometer tips

2006

Purpose To evaluate the adequacy of common disinfection regimens for disposable tonometer tips and assess if disinfection of reusable prisms or the use of disposable tips is preferable. Methods We used disposable tonometer tips, using the same material and tip diameter of standard Goldmann tonometer prism. Strains of Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Candida albicans were tested according to the European standard guidelines for disinfectants test. Antimicrobial effectiveness of the following disinfection practices has been assessed: dry wipe, Minuten wipes (Alpros), soaking in 3% hydrogen peroxide, 0.5% benzalkonium chloride, and 0.5% Pantasepts for 1, 5, …

Effect of antioxidants on the shear bond strength of composite resin to enamel following extra-coronal bleaching

2019

Background Recently patients need faster treatments, and delaying restoration is not possible following bleaching treatment. The purpose of this study was to determine the effect of antioxidants, namely 10% sodium ascorbate, 10% alpha-tocopherol, 10% green tea and 10% Aloe vera extract on the shear bond strength of composite resin to enamel following extra-coronal bleaching using 40% hydrogen peroxide. Material and Methods Seventy premolars were randomly assigned into 7 groups of 10 each. Group 1: bleaching treatment and no antioxidants application. Group 2: composite was built-up immediately after bleaching. Group 3: bleached specimens received composite build-up delayed by 2 weeks. Group …

ChemInform Abstract: Epoxidation of Olefins with a Silica-Supported Peracid in Supercritical Carbon Dioxide under Flow Conditions.

2012

Anhydrous 2-percarboxyethyl-functionalized silica (2b), a recyclable supported peracid, is a suitable reagent to perform the epoxidation of alkenes 1 in supercritical carbon dioxide at 250 bar and 40 °C under flow conditions. This procedure simplifies the isolation of the reaction products and uses only carbon dioxide as a solvent under mild conditions. The solid reagent 2b can be easily recycled by a reaction with 30% hydrogen peroxide in an acid medium.

Epoxidation of Olefins with a Silica-Supported Peracid in Supercritical Carbon Dioxide under Flow Conditions

2012

Anhydrous 2-percarboxyethyl-functionalized silica (2b), a recyclable supported peracid, is a suitable reagent to perform the epoxidation of alkenes 1 in supercritical carbon dioxide at 250 bar and 40 °C under flow conditions. This procedure simplifies the isolation of the reaction products and uses only carbon dioxide as a solvent under mild conditions. The solid reagent 2b can be easily recycled by a reaction with 30% hydrogen peroxide in an acid medium.

Crystal structure of [Cu(N-quinolin-8-yl-p-toluenesulfonamidate)2]: study of its interaction with DNA and hydrogen peroxide

2001

A new copper complex with N-quinolin-8-yl-p-toulenesulfonamide has been prepared and characterised. The compound crystallises in the triclinic system, space group P1, with a=13.457(3), b=15.067(5), c=18.589(3) A; α=112.05(2), β=93.92(2), γ=108.30(2)° and Z=4. The geometry of the Cu(II) ion is distorted square planar. The N-quinolin-8-yl-p-toulenesulfonamidate anion behaves as a bidentate ligand through the N s u l f o n a m i d a t e and N q u i n o l i n e atoms. The complex does not cleave DNA in the presence of hydrogen peroxide.

Evidence that steric factors modulate reactivity of tautomeric iron-oxo species in stereospecific alkane C-H hydroxylation

2014

A new iron complex mediates stereospecific hydroxylation of alkyl C-H bonds with hydrogen peroxide, exhibiting excellent efficiency. Isotope labelling studies provide evidence that the relative reactivity of tautomerically related oxo-iron species responsible for the C-H hydroxylation reaction is dominated by steric factors This work has been supported by the European Union (the Erasmus Mundus program), the International Research Training Group Metal Sites in Biomolecules: Structures, Regulation and Mechanisms (www.biometals.eu), and COST Action CM1003. M.C. acknowledges ERC-29910, MINECO of Spain for CTQ2012- 37420-C02-01/BQU and CSD2010-00065, catalan DIUE (2009SGR637) and an ICREA academ…

Bleaching in vital teeth : combined treatment vs in-office treatment

2019

Background The aim of this study was to verify that there will be greater whitening in teeth treated with combined bleaching than in those that have been applied a clinical one and to evaluate the efficiency of the clinical treatment, those cases in which it is not able, or it is not wanted, to carry out the home phase. Material and Methods They were used 66 extracted anterior human teeth, which were divided into two study groups. On the one hand, the clinical group (ClG) consisted of 33 teeth, which were treated with a clinical guideline using 37.5% hydrogen peroxide in a single session of 4 applications of 8 minutes. On the other hand, the combinate group (CoG) consisted of 33 teeth, whic…

Baeyer–Villiger oxidation of ketones with a silica-supported peracid in supercritical carbon dioxide under flow conditions

2009

[2-Percarboxyethyl]-functionalized silica reacts with ketones in supercritical carbon dioxide at 250 bar and 40 °C under flow conditions to yield the corresponding esters and lactones. The solid reagent can be easily recycled through treatment with 70% hydrogen peroxide in the presence of an acid at 0 °C. This procedure not only simplifies the isolation of the reaction products, but has the advantage of using only water and carbon dioxide as solvents under mild conditions.