scholarly journals Synthesis of Peroxyapatite by Hydrothermal Processing

2014 ◽  
Vol 631 ◽  
pp. 88-92 ◽  
Author(s):  
Kārlis Gross ◽  
Anastasija Jersova ◽  
Arturs Viksna
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrothermal Process ◽  
Antibacterial Properties ◽  
Hydrothermal Processing ◽  
Ammonium Persulphate ◽  
Oxygen Generation ◽  
New Process ◽  
High Temperature Processing ◽  
Apatite Lattice ◽  
Low Temperature Process

Peroxide ions in apatite provides an additional resource for imparting an antibacterial capability in apatite. A hydrothermal process has been developed for including peroxide ions into the apatite lattice. Three oxygen generation compounds, hydrogen peroxide, ammonium persulphate and paracetic acid were investigated for peroxyapatite generation. Hydrogen peroxide provides the highest peroxide containing apatite. Both the oxygen generation and the apatite lattice formation represented the two critical factors for producing peroxyapatite. Unlike with high temperature processing, the cooling rate did not influence the retained peroxide content. This new process provides a building block for investigating antibacterial properties of peroxyapatite in a low temperature process.

scholarly journals Novel Antioxidant Properties of Doxycycline

2018 ◽  
Vol 19 (12) ◽  
pp. 4078 ◽  
Author(s):  
Dahn Clemens ◽  
Michael Duryee ◽  
Cleofes Sarmiento ◽  
Andrew Chiou ◽  
Jacob McGowan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Chronic Inflammation ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Reactive Oxygen ◽  
Protein Adducts ◽  
Oxygen Species ◽  
Free System

Doxycycline (DOX), a derivative of tetracycline, is a broad-spectrum antibiotic that exhibits a number of therapeutic activities in addition to its antibacterial properties. For example, DOX has been used in the management of a number of diseases characterized by chronic inflammation. One potential mechanism by which DOX inhibits the progression of these diseases is by reducing oxidative stress, thereby inhibiting subsequent lipid peroxidation and inflammatory responses. Herein, we tested the hypothesis that DOX directly scavenges reactive oxygen species (ROS) and inhibits the formation of redox-mediated malondialdehyde-acetaldehyde (MAA) protein adducts. Using a cell-free system, we demonstrated that DOX scavenged reactive oxygen species (ROS) produced during the formation of MAA-adducts and inhibits the formation of MAA-protein adducts. To determine whether DOX scavenges specific ROS, we examined the ability of DOX to directly scavenge superoxide and hydrogen peroxide. Using electron paramagnetic resonance (EPR) spectroscopy, we found that DOX directly scavenged superoxide, but not hydrogen peroxide. Additionally, we found that DOX inhibits MAA-induced activation of Nrf2, a redox-sensitive transcription factor. Together, these findings demonstrate the under-recognized direct antioxidant property of DOX that may help to explain its therapeutic potential in the treatment of conditions characterized by chronic inflammation and increased oxidative stress.

scholarly journals Evaluation of Antioxidant and Antibacterial Properties of Magnolia champaca L (Magnoliaceae) Stem Bark Extract

2020 ◽  
Vol 23 (2) ◽  
pp. 96-102
Author(s):  
Md Mahadi Hasan ◽  
Masuma Akter ◽  
Md Ekramul Islam ◽  
Md Aziz Abdur Rahman ◽  
Mst Shahnaj Parvin
Keyword(s):  
Hydrogen Peroxide ◽  
Antioxidant Activity ◽  
Antibacterial Activity ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Antibacterial Properties ◽  
Reducing Power ◽  
Stem Bark ◽  
Total Antioxidant ◽  
Pharmacologically Active

The current study was designated to explore the antioxidant and antibacterial properties of the methanolic extract of Magnolia champaca stem bark and its different fractions. Antioxidant activity was assessed using total antioxidant capacity, ferric reducing power, DPPH, hydroxyl and hydrogen peroxide scavenging assay. Antibacterial activity was evaluated against five gram positive and five gram negative bacteria using disc diffusion assay method. Among the different fractions, chloroform fraction (CHF) and ethyl acetate fraction (EAF) showed the highest antioxidant activity whereas aqueous fraction (AQF) showed lowest activity in DPPH radical scavenging assay with IC50 of 12.12, 22.41 and 55.16 μg/ml, respectively. Both of the extracts CHF and EAF also exhibited highest total antioxidant capacity, ferric reducing power and hydrogen peroxide scavenging activity with concentration dependent manner when compared to standard BHT. Moderate to potent antibacterial activity was observed against all tested organisms compared to standard azithromycin. The results from the present study revealed that the different fractions of stem bark of M. champaca specially CHF and EAF possess antioxidant and antibacterial property which support its use in traditional medicine and suggesting that the plant may be further investigated to discover its pharmacologically active natural products. Bangladesh Pharmaceutical Journal 23(2): 96-102, 2020

Fabrication and Characterization of Cu Doped CeO2 by Hydrothermal Process for Antimicrobial Activity

2019 ◽  
Vol 391 ◽  
pp. 114-119 ◽  
Author(s):  
Yeon Bin Choi ◽  
Jeong Hun Son ◽  
Dong Sik Bae
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Hydrothermal Process ◽  
Antibacterial Properties ◽  
Reaction Times ◽  
X Ray Diffraction ◽  
Spherical Type ◽  
Average Size

Cu doped CeO2 nanopowder was synthesized by hydrothermal process at 180°C for 2~10h. The average size and distribution of the synthesized Cu doped CeO2 nanopowder was controlled by reaction times. The crystallinity of the synthesized Cu doped CeO2 nanoparticles was investigated by X-ray diffraction (XRD). The morphology of the synthesized Cu doped CeO2 nanoparticles was observed by FE-SEM. The specific surface area of the synthesized Cu doped CeO2 nanoparticles was measured by BET. The crystal size of the synthesized Cu doped CeO2 nanoparticles decreased with decreasing reaction times. The average size of the synthesized Cu doped CeO2 nanoparticles was below 10nm and narrow, respectively. The shape of the synthesized Cu doped CeO2 nanoparticles was spherical type. The specific surface area of the synthesized Cu doped CeO2 nanoparticles increased with decreasing reaction times. Antibacterial properties of Cu doped CeO2 were analyzed by MIC method. The synthesized Cu doped CeO2 nanopowders showed antibacterial properties against E.coli and B.sub bacteria.

scholarly journals A Comparison of Tissue Engineering Scaffolds Incorporated with Manuka Honey of Varying UMF

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Katherine R. Hixon ◽  
Tracy Lu ◽  
Sarah H. McBride-Gagyi ◽  
Blythe E. Janowiak ◽  
Scott A. Sell
Keyword(s):  
Hydrogen Peroxide ◽  
Tissue Engineering ◽  
Antibacterial Agent ◽  
Antibacterial Properties ◽  
Cell Number ◽  
Bacterial Clearance ◽  
Manuka Honey ◽  
Tissue Engineering Scaffolds ◽  
E Coli ◽  
Electrospun Scaffolds

Purpose. Manuka honey (MH) is an antibacterial agent specific to the islands of New Zealand containing both hydrogen peroxide and a Unique Manuka Factor (UMF). Although the antibacterial properties of MH have been studied, the effect of varying UMF of MH incorporated into tissue engineered scaffolds have not. Therefore, this study was designed to compare silk fibroin cryogels and electrospun scaffolds incorporated with a 5% MH concentration of various UMF.Methods. Characteristics such as porosity, bacterial clearance and adhesion, and cytotoxicity were compared.Results. Pore diameters for all cryogels were between 51 and 60 µm, while electrospun scaffolds were 10 µm. Cryogels of varying UMF displayed clearance of approximately 0.16 cm forE. coliandS. aureus. In comparison, the electrospun scaffolds clearance ranged between 0.5 and 1 cm. A glucose release of 0.5 mg/mL was observed for the first 24 hours by all scaffolds, regardless of UMF. With respect to cytotoxicity, neither scaffold caused the cell number to drop below 20,000.Conclusions. Overall, when comparing the effects of the various UMF within the two scaffolds, no significant differences were observed. This suggests that the fabricated scaffolds in this study displayed similar bacterial effects regardless of the UMF value.

Glycol-modified molybdate catalysts for efficient singlet oxygen generation from hydrogen peroxide

2007 ◽  
pp. 2333 ◽  
Author(s):  
Joos Wahlen ◽  
Dirk De Vos ◽  
Walther Jary ◽  
Paul Alsters ◽  
Pierre Jacobs
Keyword(s):  
Hydrogen Peroxide ◽  
Singlet Oxygen ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation

scholarly journals Exposure of Chlorpromazine to 266 nm Laser Beam Generates New Species with Antibacterial Properties: Contributions to Development of a New Process for Drug Discovery

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e55767 ◽  
Author(s):  
Mihail Lucian Pascu ◽  
Balazs Danko ◽  
Ana Martins ◽  
Nikoletta Jedlinszki ◽  
Tatiana Alexandru ◽  
...  
Keyword(s):  
New Species ◽  
Drug Discovery ◽  
Laser Beam ◽  
Antibacterial Properties ◽  
New Process

Synthesis of ZnO2 Nanocrystals Produced by Hydrothermal Process

2009 ◽  
Vol 1242 ◽  
Author(s):  
R. Esparza ◽  
A. Aguilar ◽  
A. Escobedo-Morales ◽  
C. Patiño-Carachure ◽  
U. Pal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Transmission Electron Microscopy ◽  
Hydrothermal Process ◽  
High Resolution Electron Microscopy ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Zinc Peroxide ◽  
20 Nm

ABSTRACTZinc peroxide (ZnO2) nanocrystals were directly produced by hydrothermal process. The nanocrystals were synthesized using zinc acetate as precursor and hydrogen peroxide as oxidant agent. The ZnO2 powders were characterized by X-ray powder diffraction and transmission electron microscopy. The results of transmission electron microscopy indicated that the ZnO2powders consisted of nanocrystals with diameters below to 20 nm and a faceted morphology. High resolution electron microscopy observations have been used in order to the structural characterization. ZnO2 nanocrystals exhibit a well-crystallized structure.

scholarly journals Singlet Oxygen Generation in Classical Fenton Chemistry

2019 ◽  
Author(s):  
Andrew Carrier ◽  
Saher Hamid ◽  
David Oakley ◽  
Ken Oakes ◽  
Xu Zhang
Keyword(s):  
Hydrogen Peroxide ◽  
Singlet Oxygen ◽  
Fenton Reaction ◽  
Organic Molecules ◽  
Oxygen Species ◽  
Fenton Chemistry ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Fenton Reagents ◽  
High Valent

<div><div><div><p>The Fenton reaction, the Fe-catalyzed conversion of hydrogen peroxide to reactive oxygen species (ROS) was discovered more than a century ago. It occurs widely in nature because of the ubiquity of Fenton reagents, i.e., Fe and H2O2, and ROS in environmental and biological systems; however, its mechanisms and the identity of the ROS generated under varying conditions have remained controversial. The widely accepted mechanism is that of successive oxidation and reduction of Fe2+ and Fe3+ by hydrogen peroxide to form ·OH and O2-·, respectively, where ·OH is implicated as the primary oxidant. However, the formation of high-valent Fe4+=O species has also been implicated. Herein, by systematically dissecting the contributions of various ROS species generated in the classical Fenton reaction by using specific ROS traps and scavengers, we identified that singlet oxygen (1O2) is the main ROS from pH 4–7. In contrast, although ·OH is produced in measurable quantities, it was not a major contributor to the oxidation of organic molecules.</p></div></div></div>

scholarly journals One-Step Preparation of Nitrogen-Doped Graphene Quantum Dots With Anodic Electrochemiluminescence for Sensitive Detection of Hydrogen Peroxide and Glucose

2021 ◽  
Vol 9 ◽  
Author(s):  
Zheng Yanyan ◽  
Jing Lin ◽  
Liuhong Xie ◽  
Hongliang Tang ◽  
Kailong Wang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Quantum Dots ◽  
Limit Of Detection ◽  
Hydrothermal Process ◽  
Graphene Quantum Dots ◽  
Sensitive Detection ◽  
Uniform Size ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
One Step

Simple and efficient synthesis of graphene quantum dots (GQDs) with anodic electrochemiluminescence (ECL) remains a great challenge. Herein, we present an anodic ECL-sensing platform based on nitrogen-doped GQDs (N-GQDs), which enables sensitive detection of hydrogen peroxide (H2O2) and glucose. N-GQDs are easily prepared using one-step molecular fusion between carbon precursor and a dopant in an alkaline hydrothermal process. The synthesis is simple, green, and has high production yield. The as-prepared N-GQDs exhibit a single graphene-layered structure, uniform size, and good crystalline. In the presence of H2O2, N-GQDs possess high anodic ECL activity owing to the functional hydrazide groups. With N-GQDs being ECL probes, sensitive detection of H2O2 in the range of 0.3–100.0 μM with a limit of detection or LOD of 63 nM is achieved. As the oxidation of glucose catalyzed by glucose oxidase (GOx) produces H2O2, sensitive detection of glucose is also realized in the range of 0.7–90.0 μM (LOD of 96 nM).

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