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- Thomsson, Kristina A, 1969, et al.
(författare)
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The salivary mucin MG1 (MUC5B) carries a repertoire of unique oligosaccharides that is large and diverse.
- 2002
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Ingår i: Glycobiology. - 0959-6658 .- 1460-2423. ; 12:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- The high-molecular-mass salivary mucin MG1, one of two major mucins produced by human salivary glands, plays an important role in oral health by coating the tooth surface and by acting as a bacterial receptor. Here this mucin was purified from the submandibular/sublingual saliva of a blood group O individual. The presence of MUC5B as the major mucin in this preparation was confirmed by amino acid analysis and its reactivity with the monoclonal antibody PAN H2. To structurally characterize MG1 carbohydrates the O-glycans were released by reductive beta-elimination. Nuclear magnetic resonance spectroscopy of the nonfractionated mixture showed that (1) fucose was present in blood group H, Le(a), Le(x), Le(b), and Le(y) epitopes; (2) NeuAc was mainly linked alpha 2-3 to Gal or alpha 2-6 to GalNAcol; and (3) the major internal structures were core 1 and core 2 sequences. After this preliminary analysis the released oligosaccharides were separated into neutral (56%), sialylated (26%), and sulfated (19%) fractions, with an average length of 13, 17, and 41 sugar residues, respectively. Gas chromatography-mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of mixtures of neutral and sialylated oligosaccharides revealed at least 62 neutral and 25 sialylated oligosaccharides consisting of up to 20 monosaccharide residues. These results showed that the MG1-derived oligosaccharides were much longer than those of MG2, and only a few species were found on both molecules. Thus, these two mucins create an enormous repertoire of potential binding sites for microorganisms at one of the major portals where infectious organisms enter the body.
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| 2. |
- Reddy, S. S., et al.
(författare)
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Evaluation of microstructural and dry sliding wear characteristics of pulsed Nd:YAG laser surface melted Al-Si alloys
- 2004
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Ingår i: Proceedings of the International Conference on Advances in Surface Treatment: Research and Applications, ASTRA. ; , s. 568-574
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Konferensbidrag (refereegranskat)abstract
- Aluminium-Silicon alloys are being increasingly considered for manufacture of wear prone components in automobile and aircraft industries owing to their light weight, superior corrosion resistance and high thermal conductivity, besides their amenability to processing methods such as casting. However, poor tribological characteristics have hampered industrial adoption of the above class of alloys. In principle, the tribological properties of these alloys can be improved by refining the microstructure by laser remelting techniques. Recently, Nd:YAG lasers have been used for processing of reflective materials such as Aluminium, as these lasers have better absorptivity compared to the CO2 lasers. The present study investigates the microstructural characteristics and improvements in sliding wear resistance that can result from surface melting of Al-Si alloys using a 400 W pursed Nd:YAG laser. Three different Al-Si alloys with varying Si content 5%, 12.5% and 20% have been investigated in the present study. The microstructures of the transverse cross sections of the treated samples were examined in detail and X-ray diffraction (XRD) studies carried out to ascertain changes in phase constitution. The surface melting and subsequent rapid solidification was found to cause considerable refinement of the microstructure, which in turn increased the hardness in the treated layer compared with that of bulk. The effect of laser beam scan speed on microhardness of the treated samples was evaluated. Dry sliding wear tests were conducted on treated and untreated samples of Al-12Si using a pin-on disc tribometer. The volume wear rates determined in case of the treated and untreated samples are discussed in the paper. The results have also been correlated with the morphological and microstructural characteristics noted in the laser treated specimens. Copyright © 2004 by Society for Advancement of Heat Treatment & Surface Engineering (SAHTSE).
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