Abstract：
:The photoprocesses of berberine, palmatine, coralyne, sanguinarine, flavopereirine and ellipticine were studied in several solvents. The quantum yields Φ(Δ) of singlet molecular oxygen formation of berberine, palmatine and sanguinarine are moderate in dichloromethane (0.2-0.6) and much smaller in acetonitrile or trifluoroethanol. For the other alkaloids examined, Φ(Δ) is rather independent of solvent polarity. The direct and ketone-sensitized photolysis, using steady-state irradiation at 313 nm or 248/308 nm laser pulses, was studied by absorption and fluorescence spectroscopy. Thereby, radicals were observed yielding eventually dihydro derivatives as major products, which are thermally back-converted on admission of oxygen. The quantum yield of conversion of alkaloids to dihydroalkaloids is enhanced in the presence of triethylamine. The reaction in the presence of ketones and electron or H-atom donors has a quantum yield of close to unity.
journal_name
Photochem Photobioljournal_title
Photochemistry and photobiologyauthors
Görner H,Miskolczy Z,Megyesi M,Biczók Ldoi
10.1111/j.1751-1097.2010.00880.xsubject
Has Abstractpub_date
2011-03-01 00:00:00pages
284-91issue
2eissn
0031-8655issn
1751-1097journal_volume
87pub_type
杂志文章abstract：:The seminal discovery by James Cleaver of defective DNA repair in xeroderma pigmentosum (XP) opened up an ever-expanding field of DNA repair-related disorders. In addition, it put XP on the map and has led to improved diagnosis, care and management of affected patients. In the United Kingdom, we recently established a...
journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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doi：10.1111/j.1751-1097.1989.tb04136.x
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abstract：:A 2-year field study on the effect of different light environments, obtained by using cladding materials (polyethylene films and shade net) able to cut off specific regions of the photosynthetically active radiation and ultraviolet wavebands, on the growth and phenylpropanoids content of Achillea collina grown in the ...
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章,评审
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更新日期：1996-01-01 00:00:00
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章,评审
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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更新日期：2015-09-01 00:00:00
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章,评审
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更新日期：2011-01-01 00:00:00
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/2005-11-23-RA-739
更新日期：2006-05-01 00:00:00
abstract：:Eumelanin (brown/black melanin) and pheomelanin (red/yellow melanin) in human hair can be quantified using chemical methods or approximated using spectrophotometric methods. Chemical methods consume greater resources, making them less attractive for epidemiological studies. This investigation sought to identify the sp...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.2007.00237.x
更新日期：2008-05-01 00:00:00
abstract：:Excessive sun exposure can cause sunburn, suntan, skin photoaging, and even skin cancer. Skin photoaging conflicts with the human pursuit of a young and beautiful appearance. Some research data indicate that the incidence of skin cancer in the Chinese has been increasing, although it remains lower than in whites. To e...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/php.12623
更新日期：2016-09-01 00:00:00
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1562/0031-8655(2001)073<0164:aameto>2.0.co;2
更新日期：2001-02-01 00:00:00
