Phase-Separated Structure of NBR/PVC Blends with Different Acrylonitrile Contents Investigated Using STEM-EDS Mapping Analysis.

We investigated the phase-separated structure of nitrile butadiene rubber (NBR)/polyvinyl chloride (PVC) blends with different acrylonitrile (AN) contents in the NBR, using dynamic mechanical analysis measurements and scanning-transmission-electron-microscopy (STEM)-energy-dispersive-X-ray-spectroscopy (EDS) elemental analysis. Two separate sharp tan δ peaks were observed in the blend at the lower AN content of 18.0%, whereas a broad peak was observed in the blends with the higher AN contents of 29.0 and 33.5%, due to the increase in miscibility, as expected from the decrease in the solubility parameter difference with the increasing AN content. The STEM-EDS elemental analysis for the concentration distribution showed that the NBR was mixed in the large PVC domains with a diameter of several micrometers, and the excluded PVC existed around the interface of the domain-matrix phases in the blend with the lower AN content, whereas small domains with a diameter of several tens of nanometers were dispersed in the blend with the higher AN content. The concentration difference in PVC between the PVC domain and the NBR matrix became smaller with increasing miscibility as the AN content increased although the blends contained the same PVC content of 40 wt%.

Partial Miscibility and Concentration Distribution of Two-Phase Blends of Crosslinked NBR and PVC.

We found that the blends of nitrile butadiene rubber (NBR) and polyvinyl chloride (PVC) exhibited lower critical solution temperature (LCST)-type phase behavior in which a single-phase blend tends to phase separate at elevated temperatures when the acrylonitrile content of NBR was 29.0%. The tan δ peaks, which originated from the glass transitions of the component polymers measured by dynamic mechanical analysis (DMA), were largely shifted and broader in the blends when the blends were melted in the two-phase region of the LCST-type phase diagram, suggesting that NBR and PVC are partially miscible in the two-phase structure. The TEM-EDS elemental mapping analysis using a dual silicon drift detector revealed that each component polymer existed in the partner polymer-rich phase, and the PVC-rich domains consisted of aggregated small PVC particles the size of several ten nanometers. The partial miscibility of the blends was explained by the lever rule for the concentration distribution in the two-phase region of the LCST-type phase diagram.

Dickkopf-related protein 3 promotes cell adhesion and invasion during progression of lung adenocarcinoma.

Dickkopf-related protein 3 (DKK3) is one of the DKK family (DKK1-4), an evolutionally conserved group of secreted glycoproteins characterized by two distinct cysteine-rich domains. DKK3 is considered to be a tumor suppressor gene. However, it has been shown that 30-50% of various cancers are DKK3-positive, suggesting that DKK3 may have an additional function other than tumor suppression. In this study, we focused on lung adenocarcinoma, which is the major histological type of lung cancer. We analyzed the relationship between DKK3 expression and clinicopathological features by immunohistochemistry, using 200 lung adenocarcinoma specimens. We found that 40.5% and 59.5% of cases were DKK3-positive and -negative, respectively, and that positive cases had a greater tendency for progression than negative cases (P < 0.05). Furthermore, in vitro analyses demonstrated that DKK3 suppression affected cell adhesion in three DKK3-expressing lung adenocarcinoma cell lines and that DKK3-knockdown cells were less invasive in comparison to control cells. These results suggest that DKK3 plays a role in the progression of lung adenocarcinoma by promoting cell adhesion and invasion. DKK3 might be a new extracellular cancer therapeutic target, and it seems important to clarify molecular mechanisms underlying the DKK3 functions depending on cell context.

Prominent efficiency in skin delivery of resveratrol by novel sucrose oleate microemulsion.

OBJECTIVES: To achieve an efficient skin delivery of resveratrol using sucrose fatty acid ester microemulsions and to clarify the mechanism of enhanced penetration. METHODS: Skin delivery of resveratrol using different sucrose fatty acid ester microemulsions was examined in vitro. Vehicle-skin interaction was assessed by applying blank microemulsions to skin. Skin incorporation of microemulsion components was also assessed. KEY FINDINGS: The microemulsion consisting of sucrose oleate (SO), ethanol, isopropyl myristate (IPM) and water (MESO-E) showed a prominent increase in the amount of skin incorporation of resveratrol, which was more than 5-fold higher than those of all microemulsions we previously examined. Using MESO-E, resveratrol was rapidly incorporated into skin and mainly located in the dermis. When applied in the concentration range of 5-55 mm, the amount of skin incorporation of resveratrol increased with the applied concentration up to 30 mm, whereas skin incorporation efficiency was inversely proportional to the concentration. The microemulsion-skin interaction seemed to be involved in the enhanced skin delivery process of resveratrol by MESO-E. Stratum corneum modification due to the penetration of IPM, ethanol and SO is also involved in this interaction. CONCLUSIONS: MESO-E would be a promising vehicle for the efficient skin delivery of resveratrol, especially when applied at a low concentration.