Systems containing hydrogen peroxide at high concentration. Communication 8. Thermal characteristics and stabilities of solid phases of the system. NaOh - h2O2 - H4O

1955 ◽  
Vol 4 (2) ◽  
pp. 187-191
Author(s):  
S. Z. Makarov ◽  
N. K. Grigoryeva
Keyword(s):  
Hydrogen Peroxide ◽  
Thermal Characteristics ◽  
High Concentration ◽  
Solid Phases

scholarly journals Effects of Millimolar Steady-State Hydrogen Peroxide Exposure on Inflammatory and Redox Gene Expression in Immune Cells from Humans with Metabolic Syndrome

Nutrients ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1920 ◽  
Author(s):  
Carla Busquets-Cortés ◽  
Xavier Capó ◽  
Emma Argelich ◽  
Miguel Ferrer ◽  
David Mateos ◽  
...  
Keyword(s):  
Gene Expression ◽  
Metabolic Syndrome ◽  
Hydrogen Peroxide ◽  
Immune Cells ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Mitochondrial Dynamics ◽  
High Concentration ◽  
Anti Inflammatory ◽  
Related Proteins

Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) can exert opposed effects depending on the dosage: low levels can be involved in signalling and adaptive processes, while higher levels can exert deleterious effects in cells and tissues. Our aim was to emulate a chronic ex vivo oxidative stress situation through a 2 h exposure of immune cells to sustained H2O2 produced by glucose oxidase (GOX), at high or low production rate, in order to determine dissimilar responses of peripheral blood mononuclear cells (PBMCs) and neutrophils on ROS and cytokine production, and mitochondrial dynamics-related proteins, pro/anti-inflammatory and anti-oxidant gene expression. Immune cells were obtained from subjects with metabolic syndrome. H2O2 at low concentrations can trigger a transient anti-inflammatory adiponectin secretion and reduced gene expression of toll-like receptors (TLRs) in PBMCs but may act as a stimulator of proinflammatory genes (IL6, IL8) and mitochondrial dynamics-related proteins (Mtf2, NRF2, Tfam). H2O2 at a high concentration enhances the expression of pro-inflammatory genes (TLR2 and IL1β) and diminishes the expression of mitochondrial dynamics-related proteins (Mtf1, Tfam) and antioxidant enzymes (Cu/Zn SOD) in PBMCs. The GOX treatments produce dissimilar changes in immune cells: Neutrophils were more resistant to H2O2 effects and exhibited a more constant response in terms of gene expression than PBMCs. We observe emerging roles of H2O2 in mitochondrial dynamics and redox and inflammation processes in immune cells.

scholarly journals Influence of Fluoride Concentration and pH Value of 35% Hydrogen Peroxide on the Hardness, Roughness and Morphology of Bovine Enamel

2014 ◽  
Vol 15 (4) ◽  
pp. 392-398 ◽  
Author(s):  
Wilcilene Costa Nascimento ◽  
Yasmin do Socorro Batista de Lima Gomes ◽  
Larissa Dias Alexandrino ◽  
Hilton Tulio Costi ◽  
José Otávio Carrera Silva ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Ph Value ◽  
Morphological Changes ◽  
Fluoride Concentration ◽  
Knoop Hardness ◽  
Scanning Electron Micrographs ◽  
High Concentration ◽  
Acidic Group ◽  
Bovine Enamel

ABSTRACT Aim The aim of this in vitro study was to evaluate the effects of different sodium fluoride (NaF) concentrations and pH values on the Knoop hardness (KHN), surface roughness (SR), and morphology of bovine incisors bleached with 35% hydrogen peroxide (HP). Materials and methods Sixty-five bovine incisors were fragmented (5 mm2 × 2 mm) and distributed in 5 groups: Control (unbleached), Low NaF/Acidic (35% HP + 1.3% NaF, pH 5.5), Low NaF/Neutral (35% HP + 1.3% NaF, pH 7.0), High NaF/ Acidic (35% HP + 2% NaF, pH 5.5), and High NaF/Neutral (35% HP + 2% NaF, pH 7.0). KHN analysis was performed with a microhardness tester under a load of 25 gf for 5 seconds. The average SR was obtained with a rugosimeter. KHN and SR were analyzed before and after treatments. For morphological analysis, specimens were dehydrated and gold-sputtered, and scanning electron micrographs were obtained and analyzed by 3 examiners with a double-blinded technique. KHN and SR results were analyzed by one-way ANOVA and Tukey's test (p < 0.05). Results Only the Low NaF/Acidic and Low NaF/Neutral groups showed significant differences between the initial and final KHN values. All bleached groups presented significant differences between the initial and final SR values. Among the bleached groups, the least and most morphological changes were shown by the High NaF/Neutral and the Low NaF/Acidic group, respectively. Conclusion Treatment with 35% HP and 2% NaF at pH 7.0 promoted the least changes in morphology, hardness and roughness among the bleached groups. Clinical significance In-office bleaching with high-concentration HP and 2% NaF at neutral pH promoted the least changes in enamel hardness, SR, and morphology compared to other treatments. How to cite this article Nascimento WC, Gomes YSBL, Alexandrino LD, Costi HT, Silva JOC Jr, Silva CM. Influence of Fluoride Concentration and pH Value of 35% Hydrogen Peroxide on the Hardness, Roughness and Morphology of Bovine Enamel. J Contemp Dent Pract 2014;15(4):392-398.

Efficient hydrogen peroxide synthesis by metal-free polyterthiophene via photoelectrocatalytic dioxygen reduction

2020 ◽  
Vol 13 (1) ◽  
pp. 238-245 ◽  
Author(s):  
Wenjun Fan ◽  
Bingqing Zhang ◽  
Xiaoyu Wang ◽  
Weiguang Ma ◽  
Deng Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oxygen Reduction ◽  
Cost Effective ◽  
High Concentration ◽  
Metal Free ◽  
Dioxygen Reduction ◽  
Polymeric Semiconductor ◽  
Hydrogen Peroxide Synthesis

We demonstrate the metal-free polymeric semiconductor pTTh as a selective and efficient photocathode for photoelectrochemical oxygen reduction to a high concentration of H2O2 in a cost-effective way.

A-101, a Proprietary Topical Formulation of High-Concentration Hydrogen Peroxide Solution

2018 ◽  
Vol 44 (3) ◽  
pp. 330-340 ◽  
Author(s):  
Janet C. DuBois ◽  
Michael Jarratt ◽  
Brian B. Beger ◽  
Mark Bradshaw ◽  
Christopher V. Powala ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Peroxide Solution ◽  
Topical Formulation ◽  
High Concentration

scholarly journals Effect of Metronidazole on the Growth of Vaginal Lactobacilliin vitro

2001 ◽  
Vol 9 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Jose A. Simoes ◽  
Alla A. Aroutcheva ◽  
Susan Shott ◽  
Sebastian Faro
Keyword(s):  
Adverse Effect ◽  
Hydrogen Peroxide ◽  
Antimicrobial Agent ◽  
Clinical Laboratory ◽  
National Committee ◽  
Broth Microdilution ◽  
High Concentration ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
The Ideal

Objective:To determine whether metronidazole has an adverse effect on the growth ofLactobacillus.Methods:Hydrogen peroxide- and bacteriocin-producing strains ofLactobacilluswere used as test strains. Concentrations of metronidazole used ranged from 128 to 7000 μg/ml. Susceptibility to metronidazole was conducted by the broth microdilution method recommended by the National Committee for Clinical Laboratory Standards.Results:Growth ofLactobacilluswas partially inhibited at concentrations between 1000 and 4000 μg/ml (p= 0.014). Concentrations ≥ 5000 μg/ml completely inhibited growth ofLactobacillus. Concentrations between 128 and 256 μg/ml stimulated growth ofLactobacillus(p= 0.025 and 0.005, respectively). Concentrations of metronidazole between 64 and 128 μg/ml or ≥ 512 μg/ml did not have an inhibitory or a stimulatory effect on the growth ofLactobacilluscompared to the control.Conclusions:High concentration of metronidazole, i.e. between 1000 and 4000 μg/ml, partially inhibited the growth ofLactobacillus. Concentrations ≥ 5000 μg/ml completely suppressed the growth ofLactobacillus. Concentrations between ≥ 128 and ≤ 256 μg/ml stimulated the growth ofLactobacillus. Further investigation to determine the ideal concentration of metronidazole is needed in order to use the antimicrobial agent effectively in the treatment of bacterial vaginosis.

Seminal plasma has limited counteracting effects following induction of oxidative stress in donkey spermatozoa

2020 ◽  
Vol 32 (6) ◽  
pp. 619
Author(s):  
Marion Papas ◽  
Jaime Catalan ◽  
Sebastián Bonilla-Correal ◽  
Sabrina Gacem ◽  
Jordi Miró ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Sperm Motility ◽  
Seminal Plasma ◽  
Mitochondrial Membrane ◽  
Skim Milk ◽  
Sperm Parameters ◽  
High Concentration

The aim of this study was to evaluate the response of donkey spermatozoa to oxidative stress induced by hydrogen peroxide, and to determine whether the presence of seminal plasma modulates the sperm response to that stress. Nine ejaculates were collected, extended in skim milk extender and split into two aliquots. Seminal plasma was removed from the first but not second aliquot. Samples were subsequently split into four aliquots supplemented with different concentrations of commercial hydrogen peroxide (0, 100 and 250µM and 50mM). Aliquots were incubated at 37°C under aerobic conditions and several sperm parameters, namely motility, viability, intracellular levels of peroxides and superoxides and mitochondrial membrane potential, were evaluated at 0, 1 and 3h. Exposure to hydrogen peroxide markedly decreased sperm motility but had much less of an effect on sperm viability, mitochondrial membrane potential and intracellular reactive oxygen species levels. A protective effect of seminal plasma against the loss of sperm motility was not apparent, but some kinetic parameters and relative levels of superoxides were better maintained when seminal plasma was present together with high concentration of hydrogen peroxide. In conclusion, oxidative stress induced by hydrogen peroxide reduces donkey sperm motility and has a less apparent effect on other sperm parameters. Finally, seminal plasma is only able to partially ameliorate the detrimental effect of this induced stress.

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