Role of Free Radicals/Reactive Oxygen Species in MeHg Photodegradation: Importance of Utilizing Appropriate Scavengers

2017 ◽  
Vol 51 (7) ◽  
pp. 3784-3793 ◽  
Author(s):  
Xiaoxiao Han ◽  
Yanbin Li ◽  
Dan Li ◽  
Chang Liu
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Oxygen Species

scholarly journals Environmentally persistent free radicals are ubiquitous in wildfire charcoals and remain stable for years

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Gabriel Sigmund ◽  
Cristina Santín ◽  
Marc Pignitter ◽  
Nathalie Tepe ◽  
Stefan H. Doerr ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Pyrogenic Carbon ◽  
Spin Resonance ◽  
Long Time ◽  
High Concentrations

AbstractGlobally landscape fires produce about 256 Tg of pyrogenic carbon or charcoal each year. The role of charcoal as a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species, is poorly constrained. Here, we analyse 60 charcoal samples collected from 10 wildfires, that include crown as well as surface fires in forest, shrubland and grassland spanning different boreal, temperate, subtropical and tropical climate. Using electron spin resonance spectroscopy, we measure high concentrations of environmentally persistent free radicals in charcoal samples, much higher than those found in soils. Concentrations increased with degree of carbonization and woody fuels favoured higher concentrations. Moreover, environmentally persistent free radicals remained stable for an unexpectedly long time of at least 5 years. We suggest that wildfire charcoal is an important global source of environmentally persistent free radicals, and therefore potentially of harmful reactive oxygen species.

Extremely enhanced contaminant decomposition catalyzed by hemin via the coupling of persistent free radicals and ascorbic acid

2015 ◽  
Vol 51 (89) ◽  
pp. 16139-16142 ◽  
Author(s):  
Yuyuan Yao ◽  
Bin Jiang ◽  
Yajun Mao ◽  
Juan Chen ◽  
Zhenfu Huang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Ascorbic Acid ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Environmental Pollutant ◽  
Ros Generation ◽  
Oxygen Species ◽  
Positive Role ◽  
Rate Enhancement

A positive role of PFRs in enhancing reactive oxygen species (ROS) generation for an extreme rate enhancement in environmental pollutant decomposition is reported.

Ovariectomy and its Antioxidative Effect on Bone

2010 ◽  
Author(s):  
Durg V. Rai ◽  
Harcharan Singh Ranu
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Bone Loss ◽  
Wistar Rats ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Female Wistar Rats ◽  
The Impact

Ovarian hormone deficiency increases the generation of reactive oxygen species. Oxidative stress due to reactive oxygen species (ROS) can cause oxidative damage to cells. Cells have a number of defense mechanisms to protect themselves from the toxicity of ROS. There is increasing evidence of the role of free radicals in bone resorption and bone loss. Ovariectomised female wistar rats had been used as the animal model for the study of osteoporosis. Even though, there are studies portraying the role of free radicals in bone loss, the defense mechanism adapted by bone in ovariectomised animals remains obscure. So, the impact of ovariectomy on the bone antioxidant system in rats was investigated. Twenty female wistar rats were taken and divided into two groups: ovariectomised and control. It had been found that a significant (p<0.001) decrease in the activity of various enzymes like CAT (catalase), SOD (superoxide dismutase) (p<0.001), GST (glutathione-s-transferase). However, an increase in the malondialdehyde levels was found to be 30% in the ovariectomised rats as compared to the controls. Thus the study elucidates the oxidative stress in bone under ovariectomy.

scholarly journals Role of Melatonin in Angiotensin and Aging

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4666
Author(s):  
Ahmet Ozer Sehirli ◽  
Serkan Sayıner ◽  
Ugochukwu Chukwunyere ◽  
Nedime Serakinci
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Angiotensin Ii ◽  
Reactive Oxygen ◽  
Mitochondrial Calcium ◽  
Oxygen Species ◽  
Age Related ◽  
Mitochondrial Calcium Uptake

The cellular utilization of oxygen leads to the generation of free radicals in organisms. The accumulation of these free radicals contributes significantly to aging and several age-related diseases. Angiotensin II can contribute to DNA damage through oxidative stress by activating the NAD(P)H oxidase pathway, which in turn results in the production of reactive oxygen species. This radical oxygen-containing molecule has been linked to aging and several age-related disorders, including renal damage. Considering the role of angiotensin in aging, melatonin might relieve angiotensin-II-induced stress by enhancing the mitochondrial calcium uptake 1 pathway, which is crucial in preventing the mitochondrial calcium overload that may trigger increased production of reactive oxygen species and oxidative stress. This review highlights the role and importance of melatonin together with angiotensin in aging and age-related diseases.

Effects of polyphenols in aging and neurodegeneration associated with oxidative stress

2021 ◽  
Vol 28 ◽  
Author(s):  
Francisca Rivas ◽  
Carlos Poblete-Aro ◽  
María Elsa Pando ◽  
María José Allel ◽  
Valentina Fernandez ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Nitrogen Species ◽  
Reactive Oxygen ◽  
Reactive Nitrogen ◽  
Oxygen Species ◽  
Nitrogen Species ◽  
Over Time

: Aging is defined as the functional loss of tissues and organs over time. This is a biological, irreversible, progressive, and universal process that results from genetic and environmental factors, such as diet, physical activity, smoking, harmful alcohol consumption, and exposure to toxins, among others. Aging is a consequence of molecular and cellular damage built up over time. This damage begins with a gradual decrease in physical and mental capacity, thus increasing the risk of neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. Neuronal, functional, and structural damage can be explained by an imbalance among free radicals, reactive oxygen species, reactive nitrogen species, and antioxidants, which finally lead to oxidative stress. Due to the key role of free radicals, reactive oxygen species, and reactive nitrogen species, antioxidant therapy may reduce the oxidative damage associated with neurodegeneration. Exogenous antioxidants are molecules that may help maintain the balance between the formation and elimination of free radicals, thus protecting the cell from their toxicity. Among them, polyphenols are a broad group of secondary plant metabolites with potent antioxidant properties. Here, we review several studies that show the potential role of polyphenol consumption to prevent, or slow down, harmful oxidative processes linked to neurodegenerative disorders.

Mechanism of Cr(VI) reduction by humin: Role of environmentally persistent free radicals and reactive oxygen species

2020 ◽  
Vol 725 ◽  
pp. 138413 ◽  
Author(s):  
Jun Xu ◽  
Yunchao Dai ◽  
Yafang Shi ◽  
Song Zhao ◽  
Haixia Tian ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Free Radicals ◽  
Reactive Oxygen ◽  
Oxygen Species
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