Sentences with phrase «of hydroxyl radicals»

The results suggest that vitamin A binds iron during the digestive process and forms a complex that acts as a chelating agent, thus blocking the effect of hydroxyl radicals present in phytates and polyphenols [4].

Specifically, the scientists measured the yields of hydroxyl radicals and nitrite ions produced by the so - called acoustic cavitation of the bubbles.

The researchers showed that quantum mechanical tunneling greatly enhances the production rate of hydroxyl radicals in alkene ozonolysis reactions, which sever multiple bonds under atmospheric conditions.

These hydrocarbons, together with olefinic minor LPG components, furnish substantial amounts of hydroxyl radical reactivity, a major precursor to formation of the ozone component of urban smog.

«For example, in the future methane levels could increase as a result of increased natural gas and energy use, climate change feedbacks and / or a decrease in the global abundance of the hydroxyl radical, which chemically removes methane from the atmosphere.»

Carbon monoxide has been the largest user of the hydroxyl radical, and so the main culprit in what Levine has calculated to be a possible 25 per cent decline of the radical in the atmosphere between 1950 and 1985.

A final possibility is that there has been increased formation of the hydroxyl radical in the atmosphere — perhaps caused by the thinning of the ozone layer, which allows more ultraviolet radiation to reach low levels.

But in recent years chemists have been increasingly concerned that the atmosphere's reservoir of the hydroxyl radical, and hence the efficiency of its «cleansing service», has been overstretched by the build - up of pollutants such as methane, carbon monoxide and sulphur dioxide.

«[D] ietary phytate, rather than fiber per se, might be the most important variable governing the frequency of colon [ic] cancer,» as we know phytate is «a powerful inhibitor of [the] iron - mediated production of hydroxyl radical [s], a particularly dangerous» type of free radical.

Model simulation of the hydroxyl radical concentration in the atmosphere.

Not exact matches

Red represents hydroxyl radicals, markers of flame.

The team described the results in a recently published paper titled «Selective deuteration illuminates the importance of tunneling in the unimolecular decay of Criegee intermediates to hydroxyl radical products.»

Hydroxyl radicals are important because of their role in breaking down many pollutants, although in large concentrations, they also contribute to the formation of smog.

Methane is normally held in check by the hydroxyl radical (OH), which scrubs nearly all of it out of the atmosphere within a decade.

«All three of these molecules are removed by the same process — reaction with hydroxyl,» a radical formed from water in the atmosphere, explains Nobel Prize - winning chemist F. Sherwood Rowland, who participated in the research.

In the current work, the team filled the chamber with sulfur dioxide and pinnanediol (an oxidation product of alpha - pinene) and then generated hydroxyl radicals (the dominant oxidant in Earth's atmosphere).

Since these processes require the presence of a certain chemical substance, the so called hydroxyl (= OH) radical, this part of the atmosphere is called the «OH shield.»

The reactions are performed by hydroxyl radicals (· OH) created by the decomposition of hydrogen peroxide, a powerful oxidizing agent that is used in both household and industrial settings.

Until now, scientists had focused much of their attention on the hydroxyl radical, which reacts very efficiently in the atmosphere.

Among biogenic volatile organic molecules is a class of compounds called monoterpenes, which react with ozone, hydroxyl radicals, nitrogen oxides, and other gases in the atmosphere.

Hydroxyl radicals and methanol gas can react to make methoxy radicals, but only if they have enough energy, which is impossible in the cold of space.

The hydroxyl radical consisting of one hydrogen and one oxygen atom, is one of the most common free radicals in the air and is therefore often referred as the detergent of the atmosphere.

This breakdown process results in the creation of more air pollutants, including hydroxyl and nitrate radicals, which further increase the breakdown rate of plant odors.

In addition to providing the air we breathe and the weather we experience, the troposphere is laced with a compound called the hydroxyl radical — abbreviated OH — which bonds to pollutants like bromines and droplets of sulfates called aerosols.

These experiments will first quantify the poorly - known production rates of a) nitric oxide (NO) and b) hydroxyl radicals (OH) by cosmic radiation.

Hydroxyl radicals are sometimes called «detergents of the atmosphere» since they trigger the degradation of pollutants.

However, up to 2 % of electrons which are transferred through the respiratory chain lead to the formation of reactive oxygen species (ROS) in the form of superoxide anion (O 2 −), hydrogen peroxide (H2O2), and hydroxyl radical (OH.)

Molecular hydrogen acts as a selective antioxidant, targeting only the worst of the free radicals, the hydroxyl free radical (also known as OH).

One theory is that a small amount of silver goes into solution by forming a compound of AgOH with the free hydroxyl radicals in the water.

The two most common ways of creating what is a false alkalinity are use of bicarbonates or drinking water from machines that make alkaline water by chemically splitting water into a retained hydroxyl radical that is alkaline and an acid proton that is flushed away.

In the case of alkaline water, hydroxyl radicals are so caustic that the body has multiple mechanisms for preventing such molecules from getting to the cells or systems of the body.

Use of iron chelators in preventing hydroxyl radical damage: Adult Respiratory Distress Syndrome as an experimental model for the pathophysiology and treatment of oxygen - radical - mediated tissue damage.

But when you have excessive iron, it catalyzes the formation of excessive hydroxyl free radicals from the peroxide, which decimate your mitochondrial DNA, mitochondrial electron transport proteins and cellular membranes.

While there are many types of free radicals that can be formed, the most common in aerobic (oxygen breathing) organisms are oxygen free radicals, often referred to as Reactive Oxygen Species (ROS), which include superoxides, hydroxyl anions, hydrogen peroxide and singlet oxygen.»

These free radicals (such as: superoxide, hydroxyl radical, and peroxynitrite) are controlled by antioxidant systems and when these systems can't cope with the amount of free radicals produced these free radicals scavenge for electrons from proteins, cell membranes, and DNA.

It has been tested under laboratory conditions for effectiveness against a variety of free radicals, including singlet oxygen, super-oxide, and hydroxyl radicals.

[3] In a recent in vitro study, researchers from the department of pathology at Okayama University Medical School in Japan found that Asian ginseng extract inhibited hydroxyl radical formation.

and 1998 snippets Methane now contributes about 20 % to the increased direct radiative forcing by greenhouse gases compared to preindustrial times [Shine et al., 1995] Oxidation of CH4 in the troposphere produces carbon monoxide (CO), can lead production of ozone (03), and involves atmospheric oxidant, the hydroxyl radical (OH).

Re: 121: Methane lifetime is a function of the oxidative capacity of the atmosphere (namely, hydroxyl radical abundance).

Hydroxyl radical (OH): An important chemical scavenger of many trace gases in the atmosphere that are greenhouse gases.

The gas - phase reaction of methane sulfonic acid with the hydroxyl radical without and with water vapor

Third, although many of the individual steps have been established experimentally (18), surprisingly, the mechanism of production of MSA from OSC gas phase oxidation by hydroxyl radicals (OH, daytime) and nitrate radicals (nighttime) remains unclear (31).

Specifically, he has examined hydroxyl radicals, which are water molecules stripped of one hydrogen atom.

Don't worry about that, methanol is going to be far worse and when large quantities of hydrogen gas are released into the upper atmosphere there is going to be all sorts of fun with ozone, hydroxyl radical and NOx levels.

Instead, the culprit may be the reduced availability of highly reactive «detergent» molecules called hydroxyl radicals (OH) that break methane down.

First, the main chemical that reacts with methane in the atmosphere is the hydroxyl radical (OH), thus more methane means that the concentration of OH goes down.

In the Supplementary Report (IPCC, 1992) to the FAR, the indirect chemical effects of CO, NOx and VOC were reaffirmed, and the feedback effect of CH4 on the tropospheric hydroxyl radical (OH) was noted, but the indirect RF values from the FAR were retracted and denoted in a table with «+», «0» or «--».