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Topic: Singlet oxygen

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	OXYGEN CAPS - Oxygen Supplement
		It is normally produced by healthy white blood cells to literally kill invading bacteria as the singlet oxygen stimulates the oxidation-reduction cycle, which includes detoxification functions in the body, as well as the destruction of anaerobic pathogens.
		The singlet oxygen they produce literally kills invading bacteria as it stimulates the oxidation reduction cycle, which includes detoxification functions in the body as well as the destruction of anaerobic pathogens.
		Oxy•Gen Caps is packaged in bottles of 64 capsules and are recommended to be taken two capsules at one time with water from one to three times per day as desired.
	pages.prodigy.com /bvds83a/ak8119.htm (1331 words)

	Oxygen Analysis Testing Resources - Midwest Microlabs
		Oxygen is a major component of air, produced by plants during photosynthesis, and is necessary for aerobic respiration in animals.
		Singlet oxygen, a name given to several higher energy species of molecular oxygen in which all the electron spins are paired, is much more reactive towards common organic molecules.
		Liquid oxygen is attracted to a magnet to a sufficient extent that a bridge of liquid oxygen may be supported against its own weight between the poles of a powerful magnet, in laboratory demonstrations.
	www.midwestlab.com /resources/oxygen_testing/oxygen-testing.asp (561 words)

	The significance of oxygen utilisation (Site not responding. Last check: 2007-09-10)
		Oxygen radicals or ROS are formed physiologically from two to five per cent of the oxygen used in cells.
		Oxygen is normally relatively slow to react but in both the human body and in plant organisms a highly reactive form of oxygen is formed continually in order to improve oxygen permeation.
		Singlet oxygen is not, as claimed elsewhere in the literature, an "oxygen radical".
	www.i-c-m.org.uk /journal/2004/feb/003.htm (1631 words)

	Singlet oxygen - Wikipedia, the free encyclopedia
		The energy difference between ground state and singlet oxygen is 94.2 kJ/mol and corresponds to a transition in the near-infrared at ~1270 nm.
		The chemistry of singlet oxygen is different from that of ground state oxygen.
		However, at high singlet oxygen concentrations, the fluorescence of the so-called singlet oxygen dimol (simultaneous emission from two singlet oxygen molecules upon collision) can be observed as a red glow at 634 nm.
	en.wikipedia.org /wiki/Singlet_oxygen (535 words)

	Mechanisms of Carotenoid Antioxidant Behavior
		Carotenoids "quench" singlet oxygen primarily by a physical mechanism, in which the excess energy of singlet oxygen is transferred to the carotenoid's electron-rich structure.
		Singlet oxygen was generated chemically in homogenous chloroform-ethanol solution; a known amount of the quenching compound was added and the quenching rate constant calculated from the decrease in singlet oxygen-generated infrared chemiluminescence.
		Singlet oxygen was generated by photoirradiation with methylene blue (water-soluble) or 12-(1-pyrene)dodecanoic acid ("P-12", lipid-soluble) as photosensitizing agents.
	www.astaxanthin.org /carot-antiox.htm (7168 words)

	Oxygen - Wikipedia, the free encyclopedia
		In the 19th century, oxygen was often mixed with nitrous oxide to promote an analgesic effect; a stable 50% gaseous mixture (Entonox) is commonly used in medicine today as an analgesic, and 30% oxygen with 70% nitrous oxide is the common basic anaesthetic mixture.
		In the case of spacesuits, oxygen partial pressure in the breathing gas is typically about 0.30 bar (1.4 times normal), and oxygen partial pressure in the astronaut's blood (due to downward adjustments due to water vapor and CO in the alveoli) is close to sea-level normal of 0.14 bar.
		Hypoxia (environmental) for oxygen depletion in aquatic ecology
	en.wikipedia.org /wiki/Oxygen (2713 words)

	Oxy-Oxc (Magnesium Peroxide -180 CP
		Probably, the most common effect of OXYGEN is a feeling of increased energy. In today's environment, oxygen** levels in our atmosphere are reduced by about 50% from what they used to be.
		In addition, all living matter contains oxygen, which is combined with other elements, not only as water in all cellular and circulatory fluids, but also as a component of all organic compounds such as carbohydrates (sugars, starches, cellulose, and fiber), glycogen, fats and proteins.
		The singlet oxygen they produce literally kills invading bacteria as the singlet oxygen stimulates the oxidation-reduction cycle, which includes detoxification functions in the body as well as the destruction of anaerobic pathogens.
	www.healingedge.net /store/more_oxyoxc.html (982 words)

	Supersonic singlet delta oxygen aerosol generator - Patent 4668498
		The method of claim 5 wherein said separation step includes diverting said major amount of said gaseous singlet delta oxygen through a series of oblique shock waves, a major portion of said liquid droplets being unable to be diverted because of their inertia.
		Singlet delta oxygen is generated on contact of Cl.sub.2 gas with an aqueous solution of basic H.sub.2 O.sub.2 (hypochlorite H.sub.2 O.sub.2 reaction) in accordance with the equation
		Still another object of the present invention is to reduce the pressure and temperature ordinarily present during the chemical reaction for forming singlet delta oxygen to minimize the evolution of water vapor.
	www.freepatentsonline.com /4668498.html (3123 words)

	Connections March 1998 Issue - Photosensitization (Site not responding. Last check: 2007-09-10)
		Singlet oxygen (1O2) is an excited form of molecular oxygen we breathe.
		Behind this singlet oxygen photosensitization example, there is the lab instrumentation, data acquisition, and computers, all of which is the necessary but even more boring matter.
		Routinely, the quantum yield of singlet oxygen formation can be calculated relative to the standard by comparing the integrated steady state intensities of phosphorescence that are normalized to the same number of absorbed photons and corrected for self-quenching.
	www.niehs.nih.gov /Connections/1998/march/photo.htm (558 words)

	The Role of Melatonin in the Biological Effects of Magnetic Fields - Research Information on the EMFRAPID Program (1994 ...
		Singlet oxygen, a particularly reactive form of molecular oxygen, is responsible for phototoxic responses in humans subjected to the simultaneous action of light and photoactive compounds such as non-steroidal anti-inflammatory drugs, PDT agents, or some natural pigments.
		Singlet oxygen was photogenerated by a single laser pulse excitation (exc = 335 nm) of perinaphthalene in acetonitrile.
		The interaction between singlet oxygen and quenchers (melatonin, 6-hydroxy melatonin, etc.,) was measured by monitoring singlet oxygen radiative lifetime at 1270 nm at various quencher concentrations.
	www.niehs.nih.gov /emfrapid/intrmurabs/chignell.html (546 words)

	Photodynamic Therapy (Site not responding. Last check: 2007-09-10)
		The concentration of singlet oxygen in cells has been shown to be directly proportional to the rate of cell death.
		This singlet state of oxygen has a lifetime of 15-45 minutes, and is the destructive agent causing apoptosis in photodynamic therapy.
		The singlet and the triplet state of oxygen are separated by 92 kJ/ mol, thus the light that is needed to excite the molecule must provide this much energy per mol.
	www.unc.edu /~eagreer8/Photodynamic_Therapy.html (1556 words)

	Part II: Pro-oxidants and Singlet Oxygen
		Singlet oxygen is not a free radical, but is a reactive oxygen specie.
		Singlet oxygen is an excited electronic state of oxygen which means that it contains more energy than the "ground" state or normal molecular oxygen.
		In the human, the action of some enzymes produces singlet oxygen in the dark regions of the body such as myeloperoxidase of macrophages.
	www.drpasswater.com /nutrition_library/packer_interview2.html (3422 words)

	Research - What is Singlet Oxygen?
		Singlet oxygen is the lowest excited state of the dioxygen molecule.
		In solution, the singlet oxygen is often prepared by a process called photosensitization.
		A photosensitizer is irradiated to its singlet excited state, followed by conversion (called intersystem crossing) to its triplet excited state.
	www.calstatela.edu /dept/chem/selke/r-1.htm (255 words)

	NIR Applications
		Singlet oxygen (i.e., the lowest excited electronic state of molecular oxygen) is an important intermediate in a broad range of oxygenation reactions.
		To optically monitor singlet oxygen's role in photo-oxygenation reactions, researchers measure its weak phosphorescence in the near-infrared portion of the spectrum.
		The vertical lines in the singlet oxygen images derive from inhomogeneities in the intensity profile of the Xe lamp as well as from differences in the gain of respective elements in the detector array (i.e., "hot" pixels).
	www.roperscientific.com /nir/NIRapps.html (878 words)

	Chemistry of Oxidation
		Oxygen in the air we breathe is in its "ground" (not energetically excited) state and is symbolized by the abbreviation
		Singlet oxygen is produced as a result of natural biological reactions and by photosensitization by the absorption of light energy.
		According to rules of physical chemistry, the "relaxation" (excess energy loss) of singlet oxygen back to the triplet state is "spin forbidden" and thus singlet oxygen has a long lifetime for an energetically excited molecule, and must transfer its excess energy to another molecule in order to relax to the triplet state.
	www.astaxanthin.org /oxidation.htm (1572 words)

	Invitrogen - Molecular Probes - Section 18.2 - Generating and Detecting Reactive Oxygen Species
		Singlet oxygen is responsible for much of the physiological damage caused by reactive oxygen species, including nucleic acid modification through selective reaction with deoxyguanosine.
		Before reaction with singlet oxygen, this probe initially exhibits weak blue fluorescence with excitation peaks at 372 and 393 nm and emission peaks at 395 and 416 nm.
		In the presence of singlet oxygen, however, it emits a green fluorescence similar to that of fluorescein (excitation/emission maxima ~504/525 nm).
	probes.invitrogen.com /handbook/sections/1802.html (7322 words)

	Singlet Oxygen: Generation and Properties
		Oxygen comprises 21% of the atmosphere, 89 % of seawater by weight, and at least 47% of the Earth's crust..
		Kautsky found that the presence of oxygen extinguishes or quenches the fluorescence of the trypaflavine, and in the same system, the colorless form of the dye malachite green (the leuco dye), also adsorbed on silica gel, was converted to the normal bright green form.
		Interestingly, oxygen is required for the initial photochemical reaction and its depletion initiates the clinical response.
	www.photobiology.com /educational/len2/singox.html (4056 words)

	Professor Christopher S. Foote
		Singlet oxygen is very toxic to organisms because it reacts with important biological molecules such as unsaturated lipids, oxidizable amino acids, and nucleic acids, particularly guanosine derivatives.
		Singlet oxygen also reacts with many organic compounds to give adducts which have utility in synthesis or are biological intermediates.
		A mechanistic example is the use of primary and secondary isotope effect studies to demonstrate the intermediacy of a perepoxide in the ene reaction of singlet oxygen with alkenes.18 A particularly interesting case involves trans-cyclooctene.
	www.chem.ucla.edu /dept/Organic/CSF_Brochure.html (1185 words)

	Vitamin C derivatives as antioxidant agents
		Cellular protection against singlet oxygen damage may be provided by a number of compounds capable of acting as quenchers.
		Ascorbate behaves as a weak singlet oxygen quencher, it is in fact a better one-electron reductant than tocopherol (E°'=+0.23 V), and is supposed to recycle the tocopheroxyl radical in vivo.
		Vitamin C and its derivatives readily react with oxygen in aqueous solutions, and the reaction can be easily monitored by measuring the concentration of oxygen with an electrode.
	www.netsci-journal.com /97v4/97014/vitc5.html (2387 words)

	Singlet Oxygen Demonstration Sheet (Site not responding. Last check: 2007-09-10)
		Singlet oxygen is an excited form of oxygen.
		Oxygen normally has two unpaired electrons in its outermost orbital.
		Two singlet oxygens go to the ground state by a two molecule, one photon transition.
	chemed.chem.purdue.edu /genchem/demosheets/6.4.html (101 words)

	Singlet Oxygen and Peroxyl Radicals Regulate Carotenoid Biosynthesis in Phaffia rhodozyma -- Schroeder and Johnson 270 ...
		These active oxygen species primarily derive from spillover of oxidative metabolism and also from the activities of alternative pathways of oxygen metabolism mediated by P-450 cytochromes, flavin oxygenases, and peroxisomal metabolism(18).
		Carotenoids, particularly the oxygenated xanthophylls, are synthesized at the maximum rate during the stationary phase (19) or when respiration is blocked by antimycin(10, 20).
		Singlet oxygen is detoxified by carotenoids through changes in energy state but without disruption of covalent structure of the carotenoids.
	www.jbc.org /cgi/content/full/270/31/18374 (4420 words)

	Advances in Chemical Oxygen-Iodine Laser Technology
		However, singlet-delta oxygen is not capable of acting as a lasing species because of this stability.
		The gas temperature in a typical COIL is approximately 180°K. The singlet-delta oxygen energy transfer reaction occurs with the iodine atoms and the stimulated emission reaction occurs in the laser cavity.
		The singlet-delta oxygen flows to the nozzle bank from a jet type SOG and enters the cavity-mixing chamber at approximately Mach 1.
	www.afrlhorizons.com /Briefs/Dec01/DE0104.html (1353 words)

	Scientists discover how plants disarm the toxic effects of excessive sunlight
		Donohue and his group studied a photosynthetic microbe and identified the cellular pathways it used to sense the presence of singlet oxygen and defend itself from this toxic substance.
		And by making cells more resistant to singlet oxygen, scientists may be better able to design bioenergy systems that use sunlight as an alternative to traditional fossil fuels.
		Reactive oxygen also plays an important role in human, animal and plant health, because it is often used as a host defense to inhibit the growth of unwanted microbial pathogens.
	www.eurekalert.org /pub_releases/2005-04/uow-sdh042505.php (593 words)

	Electro-Optical Device for Monitoring Instantaneous Singlet Oxygen Concentration Produced During the Treatment of Cancer
		A method and apparatus are disclosed for optically monitoring the concentration of singlet oxygen produced during photoradiation.
		A composite optical emission in the 1.27 micron frequency band is detected and electrically processed to separate a first component due to the decay of singlet oxygen from a second unwanted component due to the fluorescence of the photosensitizing dye.
		A chopped CW excitation source is used to excite the photosensitizing dye, and a signal-processing means such as a lock-in amplifier is used to separate the singlet oxygen emission component, which appears out of phase from the chopped excitation signal and the in-phase photosensitizer fluorescence.
	www.jhuapl.edu /ott/technologies/technology/Articles/P00031.asp (329 words)

	The development of efficient two-photon singlet oxygen sensitizers (Site not responding. Last check: 2007-09-10)
		Charge-transfer in the excited state of the prepared molecules was shown to play a pivotal role in the generation of singlet oxygen.
		The design principles obtained from the studies in lipophilic solvents were applied to synthesize water-soluble twophoton singlet oxygen sensitizers with the potential applicability for biological studies.
		The synthesis of porphyrins with donor-acceptor architecture was investigated and it was shown that these biologically friendly molecules could not be brought to generate singlet oxygen in a two-photon irradiation scheme.
	www.risoe.dk /rispubl/POL/ris-phd-10.htm (252 words)

	Oxy-Gen Caps for Optimum Athletic Performance
		We think of the oxygen in the air we breathe but it is everywhere.
		The most well known and most common form of oxygen is when two atoms of oxygen combine to make molecular oxygen known as 02.
		The singlet oxygen they produce literally kills invading bacteria as the singlet oxygen stimulates the oxidation- reduction cycle, which includes de oxification functions in the body, as well as the destruction of anaerobic pathogens.
	members.aol.com /lpluby/oxygen.htm (745 words)

	Singlet Oxygen Reaction Rates
		Rate constants for the chemical reaction and physical deactivation of singlet oxygen available through 1994 have been compiled.
		Second-order rate constants for interaction of singlet oxygen with more than 1900 compounds, more than 5100 measured values, are reported.
		It may be known from other studies that a particular substrate interacts with singlet oxygen totally by chemical reaction or totally by physical quenching; an example of the latter is azide ion.
	allen.rad.nd.edu /compilations/SingOx/SingOx.htm (789 words)

	Quantum Yields for Singlet Oxygen
		The fractions of singlet and triplet states quenched which produce singlet oxygen and the quantum yields of formation of singlet oxygen in fluid solutions have been critically compiled.
		Other materials which have been investigated for singlet oxygen production, such as dyes and drugs, are collected in Table 3 along with heterogeneous systems such as polymer-bound photosensitizers.
		Quantitative data for photosensitized singlet oxygen production are given in three tables containing 1,600 separate entries for 750 chemical species.
	www.rcdc.nd.edu /compilations/Qy/IntroQY.htm (801 words)

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