Synthesis of copper nanoparticles mediated by photogenerated free radicals: catalytic role of chloride anions

2010 ◽  
Vol 9 (6) ◽  
pp. 766 ◽  
Author(s):  
Natalia L. Pacioni ◽  
Andrea Pardoe ◽  
Katherine L. McGilvray ◽  
Michelle N. Chrétien ◽  
Juan C. Scaiano
Keyword(s):  
Free Radicals ◽  
Copper Nanoparticles ◽  
Catalytic Role

The Role of free radicals in female unexplained subfertility

2020 ◽  
Vol 23 (01) ◽  
pp. 01-08
Author(s):  
Ban Jaber Edan ◽  
Huda Mahmood Shakir ◽  
Naseer Jwaad Almukhtar
Keyword(s):  
Free Radicals

Study of antioxidant potential in leaves, stems, nuts of Juglans regia L.

2012 ◽  
Vol 1 (10) ◽  
pp. 79 ◽  
Author(s):  
G. Raja* ◽  
Ivvala Anand Shaker ◽  
Inampudi Sailaja ◽  
R. Swaminathan ◽  
S. Saleem Basha ◽  
...  
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Juglans Regia ◽  
Radical Scavenging ◽  
Antioxidant Compounds ◽  
Free Radical Damage ◽  
Radical Damage

Natural antioxidants can protect the human body from free radicals and retard the progress of many chronic diseases as well as lipid oxidative rancidity in foods. The role of antioxidants has protected effect against free radical damage that may cause many diseases including cancer. Primary sources of naturally occurring antioxidants are known as whole grains, fruits, and vegetables. Several studies suggest that regular consumption of nuts, mostly walnuts, may have beneficial effects against oxidative stress mediated diseases such as cardiovascular disease and cancer. The role of antioxidants has attracted much interest with respect to their protective effect against free radical damage that may cause many diseases including cancer. Juglans regia L. (walnut) contains antioxidant compounds, which are thought to contribute to their biological properties. Polyphenols, flavonoids and flavonols concentrations and antioxidant activity of Leaves, Stems and Nuts extract of Juglans regia L. as evaluated using DPPH, ABTS, Nitric acid, hydroxyl and superoxide radical scavenging activity, lipid peroxidation and total oxidation activity were determined. The antioxidant activities of Leaves, Stems and Nuts extract of Juglans regia L. were concentration dependent in different experimental models and it was observed that free radicals were scavenged by the test compounds in all the models.

scholarly journals Oxidized LDLs as Signaling Molecules

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1184
Author(s):  
Jean-Marc Zingg ◽  
Adelina Vlad ◽  
Roberta Ricciarelli
Keyword(s):  
Free Radicals ◽  
Cellular Response ◽  
Vascular System ◽  
Signaling Molecules ◽  
Scavenger Receptors ◽  
Physiological Relevance ◽  
Reactive Radicals ◽  
Accumulation Of Lipids

Levels of oxidized low-density lipoproteins (oxLDLs) are usually low in vivo but can increase whenever the balance between formation and scavenging of free radicals is impaired. Under normal conditions, uptake and degradation represent the physiological cellular response to oxLDL exposure. The uptake of oxLDLs is mediated by cell surface scavenger receptors that may also act as signaling molecules. Under conditions of atherosclerosis, monocytes/macrophages and vascular smooth muscle cells highly exposed to oxLDLs tend to convert to foam cells due to the intracellular accumulation of lipids. Moreover, the atherogenic process is accelerated by the increased expression of the scavenger receptors CD36, SR-BI, LOX-1, and SRA in response to high levels of oxLDL and oxidized lipids. In some respects, the effects of oxLDLs, involving cell proliferation, inflammation, apoptosis, adhesion, migration, senescence, and gene expression, can be seen as an adaptive response to the rise of free radicals in the vascular system. Unlike highly reactive radicals, circulating oxLDLs may signal to cells at more distant sites and possibly trigger a systemic antioxidant defense, thus elevating the role of oxLDLs to that of signaling molecules with physiological relevance.

The role of copper nanoparticles decorating polydopamine/graphene film as catalyst in the enhancement of uric acid sensing

2021 ◽  
pp. 115322
Author(s):  
Do Phuc Quan ◽  
Bui Thi Phuong Thao ◽  
Nguyen Van Trang ◽  
Nguyen Le Huy ◽  
Nguyen Quoc Dung ◽  
...  
Keyword(s):  
Uric Acid ◽  
Copper Nanoparticles ◽  
Graphene Film

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.

scholarly journals Flammable gases produced by TiO2 nanoparticles under magnetic stirring in water

Friction ◽  
2021 ◽  
Author(s):  
Pengcheng Li ◽  
Chongyang Tang ◽  
Xiangheng Xiao ◽  
Yanmin Jia ◽  
Wanping Chen
Keyword(s):  
Tio2 Nanoparticles ◽  
Quartz Glass ◽  
Dye Degradation ◽  
Mechanical Energy ◽  
Chemical Energy ◽  
Magnetic Stirring ◽  
Catalytic Role ◽  
Nanostructured Semiconductors

AbstractThe friction between nanomaterials and Teflon magnetic stirring rods has recently drawn much attention for its role in dye degradation by magnetic stirring in dark. Presently the friction between TiO2 nanoparticles and magnetic stirring rods in water has been deliberately enhanced and explored. As much as 1.00 g TiO2 nanoparticles were dispersed in 50 mL water in 100 mL quartz glass reactor, which got gas-closed with about 50 mL air and a Teflon magnetic stirring rod in it. The suspension in the reactor was magnetically stirred in dark. Flammable gases of 22.00 ppm CO, 2.45 ppm CH4, and 0.75 ppm H2 were surprisingly observed after 50 h of magnetic stirring. For reference, only 1.78 ppm CO, 2.17 ppm CH4, and 0.33 ppm H2 were obtained after the same time of magnetic stirring without TiO2 nanoparticles. Four magnetic stirring rods were simultaneously employed to further enhance the stirring, and as much as 30.04 ppm CO, 2.61 ppm CH4, and 8.98 ppm H2 were produced after 50 h of magnetic stirring. A mechanism for the catalytic role of TiO2 nanoparticles in producing the flammable gases is established, in which mechanical energy is absorbed through friction by TiO2 nanoparticles and converted into chemical energy for the reduction of CO2 and H2O. This finding clearly demonstrates a great potential for nanostructured semiconductors to utilize mechanical energy through friction for the production of flammable gases.

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