• Atmosphere
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• v.21 no.3
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• pp.301-309
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• 2011

In this study, we compared light-absorption properties of aerosols observed in East and South Asia from black carbon (BC) mass concentration, aerosol scattering (${\sigma}_s$) and absorption (${\sigma}_a$) coefficients measurements at four sites: Korea Climate Observatory-Gosan (KCO-G), Korea Climate Observatory-Anmyeon (KCO-A), Maldives Climate Observatory-Hanimaadhoo (MCO-H) and Nepal Climate Observatory-Pyramid (NCO-P). No significant seasonal variations of BC mass concentration, ${\sigma}_s$ and ${\sigma}_a$, despite of wet removal of aerosols by precipitation in summer, were observed in East Asia, whereas dramatic changes of light-absorbing aerosol properties were observed in South Asia between dry and wet monsoon periods. Although BC mass concentration in East Asia is generally higher than that observed in South Asia, BC mass concentration at MCO-H during winter dry monsoon is similar to that of East Asia. The observed solar absorption efficiency (${\alpha}$) at 550 nm, where ${\alpha}={\sigma}_a/({\sigma}_s+{\sigma}_a)$, at KCO-G and KCO-A is higher than that in MCO-H due to large portions of BC emission from fossil fuel combustion. Interestingly, ${\alpha}$ at NCO-P is 0.14, which is two times great than that in MCO-H and is about 40% higher than that in East Asia, though BC mass concentration at NCO-P is the lowest among four sites. Consistently, the highest elemental carbon to sulphate ratio is found at NCO-P.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.211-221
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• 2010

Proteoglycan is highly hydrophilic and negatively charged which enable them attract the water. The objective of study was to investigate the effects of Proteoglycan on microtensile bond strength of dentin adhesives and on architecture of dentin collagen matrix of acid etched dentin by removing the chondroitin sulphate attached on Proteoglycan. A flat dentin surface in mid-coronal portion of tooth was prepared. After acid etching, half of the specimens were immersed in 0.1 U/mL chondroitinase ABC (C-ABC) for 48 h at $37^{\circ}C$, while the other half were stored in distilled water. Specimens were bonded with the dentin adhesive using three different bonding techniques (wet, dry and re-wet) followed by microtensile bond strength test. SEM examination was done with debonded specimen, resin-dentin interface and acid-etched dentin surface with/without C-ABC treatment. For the subgroups using wet-bonding or dry-bonding technique, microtensile bond strength showed no significant difference after C-ABC treatment (p > 0.05). Nevertheless, the subgroup using rewetting technique after air dry in the Single Bond 2 group demonstrated a significant decrease of microtensile bond strength after C-ABC treatment. Collagen architecture is loosely packed and some fibrils are aggregated together and relatively collapsed compared with normal acid-etched wet dentin after C-ABC treatment. Further studies are necessary for the contribution to the collagen architecture of noncollagenous protein under the various clinical situations and several dentin conditioners and are also needed about long-term effect on bond strength of dentin adhesive.