• Macromolecular Research
• /
• v.9 no.2
• /
• pp.107-115
• /
• 2001

Poly(L-lactide-co-glycolide)(PLGA) was blended with poly[$\omega$-methacryloyloxyethyl phospho-rylcholine-co-ethylhexylmethacrylate (PMEH)] (PLGA/PMEH) to endow with new functionality i.e., to improve the cell-, tissue- and blood-compatibility. The characteristics of surface properties were investigated by measurement of contact angle goniometer, Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and electron spectroscopy for chemical analysis (ESCA). NIH/3T3 fibroblast and bovine aortic endothelial cell were cultured on control and PLGA/PMEH surfaces for the evaluation of ceil attachment and proliferation in terms of surface functionality such as the concentration of phosphoryl-choline. Also, the behavior of platelet adhesion on PLGA/PMEH was observed in terms of the surface functionality. The contact angles on control and PLGA/PMEH surfaces decreased with increasing PMEH content from 75$^{\circ}$ to about 43$^{\circ}$. It was observed from the FTIR-ATR spectra that phosphorylcholine groups are gradually increased with increasing blended amount of MPC. The experimental P percent values from ESCA analysis were more 3.28∼7.4 times than that of the theoretical P percent for each blend films. These results clearly indicated that the MPC units were concentrated on the surface of PLGA/PMEH blend. The control and PLGA/PMEH films with 0.5 to 10.0 wt% concentration of PMEH were used to evaluate cell adhesion and growth in terms of phosphorylcholine functionality and wettability. Cell adhesion and growth on PLGA/PMEH surfaces were less active than those of control and both cell number decreased with increasing PMEH contents without the effect of surface wettability. It can be explained that the fibronectin adsorption decreased with an increase in the surface density of phosphorylcholine functional group. One can conclude the amount of the protein adsorption and the adhesion number of cells can be controlled and nonspecifically reduced by the introduction with phosphorylcholine group. Morphology of the adhered platelets on the PLGA/PMEH surface showed lower activating than control and the number of adhered platelets on the PLGA/PMEH sample decreased with increasing the phosphorylcholine contents. The amount of fibrinogen adsorbed on the PLGA/PMEH surface demonstrated that the phospholipid polar group played an important role in reducing protein adsorption on the surface. In conclusion, this surface modification technique might be effectively used PLGA film and scaffolds for controlling the adhesion and growth of cell and tissue, furthermore, blood compatibility of the PLGA was improved by blending of the MPC polymer for the application of tissue engineering fields.

• Korean journal of applied entomology
• /
• v.59 no.3
• /
• pp.265-275
• /
• 2020

In this study, we analyzed the nutritional ingredients of drone pupae (16^th to 20^th instar old) to evaluate the value of bee products and provide basic data for product diversification, and the extracts prepared using these pupae were tested for physiological activity. According to the analysis of the general ingredients of the freeze-dried powder of these bee pupae, the moisture, crude protein, crude fat, and crude ash was 1.69 ± 0.07%, 48.52 ± 0.20%, 23.41 ± 0.14%, and 4.05 ± 0.02%, respectively. Vitamin C and vitamin E were 14.92 ± 0.52 mg/100 g and 6.06 ± 0.11 mg α-TE/100 g, respectively. Regarding minerals, the highest content of K (1349.13 ± 34.57 mg/100 g) and P (1323.55 ± 43.85 mg/100 g) was observed and Ca and Fe were 55.43 ± 1.51 mg/100 g and 5.49 ± 0.19 mg/100 g, respectively. The fatty acids of the water extracted freeze-dried pupae powder accounted for approximately 59.62 of saturated fatty acids and 40.38 of unsaturated fatty acids, and high-quality fatty acids such as palmitic acid (C16:0) was 35.49 ± 0.08 and oleic acid (C18:1, n-9) was 35.91 ± 0.22 (g/100 g total fatty acids). The total amino acid content was 38.99 ± 2.63 g/100 g and the free amino acid was a total of 5129.04 mg/100 g, of which 1257.68 mg/100 g was proline and 759.12 mg/100 g glutamic acid. The DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity of the drone pupae extract showed values of 0.8 for distilled water extract, 3.2 for 50% EtOH extract, 6.4 for 70% EtOH extract, and approximately 90% for 32 ㎍/mL for 100% EtOH extract. These results suggest that the main compound contributing to the antioxidant activity is a polar compound, and it is highly likely to be a low-molecular protein or a free amino acid. In conclusion, the honey bee drone pupa is excellent as a food resource and can be utilized as a new functional material for food and functional food.

• Journal of the Korean earth science society
• /
• v.39 no.1
• /
• pp.53-66
• /
• 2018

The information of surface reflectance ($R_{sfc}$) is important for the heat balance and the environmental/climate monitoring. The $R_{sfc}$ sensitivity to error-induced variables for the Geostationary Environment Monitoring Spectrometer (GEMS) retrieval from geostationary-orbit satellite observations at 300-500 nm was investigated, utilizing polar-orbit satellite data of the MODerate resolution Imaging Spectroradiometer (MODIS) and Ozone Mapping Instrument (OMI), and the radiative transfer model (RTM) experiment. The variables in this study can be cloud, Rayleigh-scattering, aerosol, ozone and surface type. The cloud detection in high-resolution MODIS pixels ($1km{\times}1km$) was compared with that in GEMS-scale pixels ($8km{\times}7km$). The GEMS detection was consistent (~79%) with the MODIS result. However, the detection probability in partially-cloudy (${\leq}40%$) GEMS pixels decreased due to other effects (i.e., aerosol and surface type). The Rayleigh-scattering effect in RGB images was noticeable over ocean, based on the RTM calculation. The reflectance at top of atmosphere ($R_{toa}$) increased with aerosol amounts in case of $R_{sfc}$<0.2, but decreased in $R_{sfc}{\geq}0.2$. The $R_{sfc}$ errors due to the aerosol increased with wavelength in the UV, but were constant or slightly decreased in the visible. The ozone absorption was most sensitive at 328 nm in the UV region (328-354 nm). The $R_{sfc}$ error was +0.1 because of negative total ozone anomaly (-100 DU) under the condition of $R_{sfc}=0.15$. This study can be useful to estimate $R_{sfc}$ uncertainties in the GEMS retrieval.