Present-day ultrahigh-pressure conditions of coesite inclusions in zircon and garnet: Evidence from laser Raman microspectroscopy

The Rhodope Metamorphic Province represents an area of continental collision between the Balkan domain to the north and the Pangaeon domain to the south. Today, exposed astride the suture zone are Palaeozoic and Mesozoic protoliths of both continental and oceanic provenance that underwent Alpine deformation and metamorphism in a subduction zone setting. From petrostructural studies the picture that emerged is one of a central, structurally lower, marble-dominated terrain (i.e. a metamorphic core complex), and a surrounding, structurally higher, gneiss-dominated terrain. Here, for the first time, we report the presence of ultrahigh-pressure metamorphic indicator minerals such as coesite, diamond and Si-Ti-Na-P-rich (i.e. majoritic) garnet in amphibolitized eclogites and garnet-biotitekyanite gneisses from localities scattered throughout the structurally higher terrain. These findings, corroborated by optical microscopy, electron microprobe analyses and in situ laser Raman microspectroscopy, suggest that the protoliths of these rocks were dragged down to mantle depths exceeding 200 km. The individual pressure-temperature paths published before for various subunits of the structurally higher terrain should henceforth be regarded as peculiarities of the exhumation path followed by the subunits.

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Multimolecular Salivary Mucin Complex Is Altered in Saliva of Cigarette Smokers: Detection of Disulfide Bridges by Raman Spectroscopy

BioMed Research International ◽

10.1155/2013/168765 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Motoe Taniguchi ◽

Junko Iizuka ◽

Yukari Murata ◽

Yumi Ito ◽

Mariko Iwamiya ◽

...

Keyword(s):

Disulfide Bonds ◽

Raman Microspectroscopy ◽

Confocal Laser ◽

Oral Epithelium ◽

Amino Acid Residues ◽

Disulfide Bridges ◽

Cigarette Smokers ◽

Laser Raman ◽

Salivary Mucin ◽

Premenopausal Female

Saliva contains mucins, which protect epithelial cells. We showed a smaller amount of salivary mucin, both MG1 and MG2, in the premenopausal female smokers than in their nonsmoking counterparts. Smokers' MG1, which contains almost 2% cysteine/half cystine in its amino acid residues, turned out to be chemically altered in the nonsmoker’s saliva. The smaller acidic glycoprotein bands were detectable only in smoker’s saliva in the range of 20–25 kDa and at 45 kDa, suggesting that degradation, at least in part, caused the reduction of MG1 mucin. This is in agreement with the previous finding that free radicals in cigarette smoke modify mucins in both sugar and protein moieties. Moreover, proteins such as amylase and albumin are bound to other proteins through disulfide bonds and are identifiable only after reduction with DTT. Confocal laser Raman microspectroscopy identified a disulfide stretch band of significantly stronger intensity per protein in the stimulated saliva of smokers alone. We conclude that the saliva of smokers, especially stimulated saliva, contains significantly more oxidized form of proteins with increased disulfide bridges, that reduces protection for oral epithelium. Raman microspectroscopy can be used for an easy detection of the damaged salivary proteins.

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