• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.501-519
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• 2003

Silk Sericin(SS) is a natural protein extracted from cocoon of bombix mori and shows moisturizing effect to the skin due to a number of hydroxyl groups in the structure. But its application to cosmetics is limited due to its poor solubility in water. In order to solve this drawback and expand its application to cosmetics, polyethyleneglycol(PEG) was conjugated with sericin by reacting activated polyethyleneglycol(ActPEG). Reaction site of sericin is tyrosine residue, which was determined by using $^1$H-NMR. Random coil structure of sericin was transformed to beta-sheet structure by conjugating polyethyleneglycol. It was confirmed that melting point of sericin-PEG conjugate was lowered compared to that of each sericin and PEG due to the interaction between sericin and PEG in crystalline structure. Self-assembled sericin-PEG nanoparticle was obtained by dialyzing with alcohol solution of sericin-PEG conjugate against water. The particle is spherical and has 200-400nm of size. The moisturizing ability of sericin-PEG nanoparticle was much higher than that of sericin itself. Incorporation of vitamin A into sericin-PEG nanoparticle was carried out by diafiltration method. The content of incorporated Vitamin A in sericin-PEG nanoparticle was 8.9 wt％. Releasing behaviour of vitamin A incorporated into nanoparticle was tested in phosphate buffer, pH 7.4 at 37$^{\circ}C$. and half-life of Vitamin A release was 43hrs. Sericin-PEG nanoparticle exhibited higher moisturing effect than sericin itself and distilled water, respectively. No toxicity and irritation were observed in animal tests. It can be expected that the self-assembled sericin-PEG nanoparticle can be developed for cosmetics.

• Analytical Science and Technology
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• v.36 no.4
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• pp.180-190
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• 2023

The presence of process related impurities in any drug or the drug product was associated with its safety, stability and efficacy. The overall literature survey proved that there is no method published on the assessment of process related impurities in brigatinib. In this study, a simple, reliable and stable HPLC qualitative method was reported for quantification of process related impurities with easy and quick extraction procedure. The impurities along with standard brigatinib was resolved on Lichrospher^® C18 (250 mm × 4.6 mm; 5 ㎛ particle size) column in room temperature using methanol, acetonitrile, pH 4.5 phosphate buffer in 55:25:20 (v/v) at 1.0 mL/min as mobile phase and UV detection at 261 nm. The method produces well resolved peaks at retention time of 4.60 min, 12.28 min, 3.37 min, 7.34 min and 8.39 min respectively for brigatinib, impurity A, B, C and D. The method produces a very sensitive detection limit of 0.0065 ㎍/mL, 0.0068 ㎍/mL, 0.0053 ㎍/mL and 0.0058 ㎍/mL for impurity A, B, C and D respectively with calibration curve linear in the concentration range of 22.5-135 ㎍/mL for brigatinib and 0.0225-0.135 ㎍/mL for impurities. The method produces all the validation parameters under the acceptable level and doesn't produces any considerable changes in peak area response while minor changes in the developed method conditions. The method can effectively resolve the unknown stress degradation products along with known impurities with less % degradation. The method can efficiently resolve and quantify the impurities in formulation and hence can suitable for the routine quality analysis of brigatinib in raw material and formulation.

• Journal of Biomedical Engineering Research
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• v.45 no.1
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• pp.20-25
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• 2024

Extracellular vesicles (EVs) are nano-sized lipid bilayer vesicles released by cells. EVs act as messengers for cell-to-cell communication. Inside, it contains various substances that show biological activity, such as proteins, lipids, nucleic acids, and metabolites. The study of EVs extracted from terrestrial organisms and stem cells on inflammatory environments and tissue regeneration have been actively conducted. However, marine organisms-derived EVs are limited. Therefore, we have extracted EVs from sea urchins belonging to the Echinoderm group with their excellent regenerative ability. First, we extracted extracellular matrix (ECM) from sea urchin gonads treated with hypotonic buffer, followed by collagenase treatment, and filtration to collect ECM-bounded EVs. The size of sea urchin gonad-derived EVs (UGEVs) is about 20-100 nm and has a round shape. The protein content was higher after EVs burst than before, which is evidence that proteins are contained inside. In addition, proteins of various sizes are distributed inside. PKH-26 was combined with UGEVs, which means that UGEVs have a lipid membrane. PHK-26-labeled UGEVs were successfully uptaken by cells. UGEVs can be confirmed to have the same characteristics as traditional EVs. Finally, it was confirmed that Schwann cells were not toxic by increasing proliferation after treatment.

• The Journal of Dong Guk Oriental Medicine
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• v.7 no.2
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• pp.97-105
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• 1999

Hepatic tissues of ICR mouse were intraperitoneally injeced with Colpomenia bullosa(CB) Extract after Triton WR-1339(TX) injection were observed to investigate the antihyperlipermic effect of CB extract for hyperlipidemic hepatic tissue caused by destruction of lipid metabolism. The hepatic tissues were obtained at hour-24, 48, and 72 after TX injection with CB extract treatment. And then these specimen were fixed in 10% neutral buffer solution and were cryocut. The tissue stained by H&E for general morphology and sudan black B for lipid distribution. The increase of hepatocyte havinig meshlike cytoplasm were shown in all hepatic lobules after TX injection and the hepatic plates were disappeared in the region of meshlike hepatocyte aggregation. But the hepatocyte having meshlike cytoplasm were disappeared and hapatic plate were rearranged in CB extract injected mouse. The number of blue black colored lipid drop in hepatic cytoplasm of mouse injected with TX were increased and the size of lipid drop were enlarged. But the number of lipid drop in hepatic cytoplasm of mouse treated CB extract were decreased and the size of lipid drop were diminished. As results indicated that the accumulation of lipid drop caused by TX injection were mitigated by the antihyperlipidermic effect of CB extract.

• Journal of Pharmaceutical Investigation
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• v.27 no.4
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• pp.303-311
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• 1997

Proliposomal patch of clenbuterol, ${\beta}_2-agonist$ bronchodilator, was prepared and its feasibility as a novel transdermal drug delivery system was examined. Proliposomal granules containing clenbuterol was prepared by a standard method using sorbitol and lecithin with (Rx 2) or without cholesterol (Rx 1). The porous structure of sorbitol in the proliposomes was maintained allowing tree flowability of the granules. Following contact with water, the granules were converted probably to liposomes almost completely within several minutes. It indicates that proliposomes may be hydrated, when they are applied on the skin under occlusive condition in vivo, by the sweat to form liposomes. Clenbuterol release from Rx 1 and Rx 2 proliposomes to pH 7.4 isotonic phospate buffer (PBS) across cellulose membrane (mol. wt. cut-off of 12000-14000) was retarded significantly compared with that from the mixture of clenbuterol powder and blank proliposomes. Interestingly, proliposomes prepared with lecithin and cholesterol (i.e., Rx 2 proliposomes) showed much more retarded release of clenbuterol than proliposomes prepared only with lecithin (i.e.. Rx 1 proliposomes), indicating that clenbuterol release from proliposomes can be controlled by the addition of cholesterol to the proliposomes. Proliposomal patches were prepared using PVC film as an occlusive backing sheet, two sides adhesive tape (urethane, 1.45 mm thickness) as a reservoir for proliposome granules and Millipore MF-membrane (0.45 mm pore size) as a drug release-controlling membrane. Rx 1 or Rx 2 proliposomes containing 4.6 mg of clenbuterol were loaded into the reservoir of the patch. Clenbuterol release from the patches to pH 7.4 PBS was determined using USP paddle (50 rpm)-over-disc release method. Clenbuterol release from the proliposomal patches was much more retarded even than from a matrix type clenbuterol patch (Boehringer Ingelheim ltd). Being consistent with clenbuterol release from the proliposomal granules, the release from the patches was highly dependent on the presence of cholesterol in the proliposomes : Patches containing Rx 2 proliposomes showed several fold slower drug release than patches containing Rx 1 proliposomes. When the patch containing Rx 1 proliposomes was applied on to the back of a hair-removed rat, clenbuterol concentration in the rat blood was maintained during 6-72 hrs. Transdermal absorption of clenbuterol from the patch was accelerated when the patch was prehydrated with 50 ml of pH 7.4 PBS before topical application. Above results indicate that sustained transdermal delivery of clenbuterol is feasible using proliposomal patches if the cholesterol content and pore size of the release rate-controlling membrane of patches, for example, are appropriately controlled.

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1386-1392
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• 2008

A gene (sll0158) putatively encoding a glycogen branching enzyme (GBE, E.C. 2.4.1.18) was cloned from Synechocystis sp. PCC6803, and the recombinant protein expressed and characterized. The PCR-amplified putative GBE gene was ligated into a pET-21a plasmid vector harboring a T7 promoter, and the recombinant DNA transformed into a host cell, E. coli BL21(DE3). The IPTG-induced enzymes were then extracted and purified using Ni-NTA affinity chromatography. The putative GBE gene was found to be composed of 2,310 nucleotides and encoded 770 amino acids, corresponding to approx. 90.7 kDa, as confirmed by SDS-PAGE and MALDI-TOF-MS analyses. The optimal conditions for GBE activity were investigated by measuring the absorbance change in iodine affinity, and shown to be pH 8.0 and $30^{\circ}C$ in a 50 mM glycine-NaOH buffer. The action pattern of the GBE on amylose, an $\alpha$-(1,4)-linked linear glucan, was analyzed using high-performance anion-exchange chromatography (HPAEC) after isoamylolysis. As a result, the GBE displayed $\alpha$-glucosyl transferring activity by cleaving the $\alpha$-(1,4)-linkages and transferring the cleaved maltoglycosyl moiety to form new $\alpha$-(1,6)-branch linkages. A time-course study of the GBE reaction was carried out with biosynthetic amylose (BSAM; $M_p{\cong}$8,000), and the changes in the branch-chain length distribution were evaluated. When increasing the reaction time up to 48 h, the weight- and number-average DP ($DP_w$ and $DP_n$) decreased from 19.6 to 8.7 and from 17.6 to 7.8, respectively. The molecular size ($M_p$, peak $M_w{\cong}2.45-2.75{\times}10^5$) of the GBE-reacted product from BSAM reached the size of amylose (AM) in botanical starch, yet the product was highly soluble and stable in water, unlike AM molecules. Thus, GBE-generated products can provide new food and non-food applications, owing to their unique physical properties.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.239-247
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• 2005

In this study, an experimental study on the sorption properties of uranium(VI) onto bentonite colloids generated from a domestic calcium bentonite (called as Gyeongju bentonite). Gyeongju bentonite has been considered as a potential candidate buffer material in the Korean disposal concept for high-level radioactive wastes. The size and concentration of the bentonite colloids used in the sorption experiment were measured by a filtration method. The result showed that the concentration of the synthesized bentonite colloid suspension was 5100ppm and the size of the most of bentonite colloids(over $98\%$) was in the range of 200-450nm in diameter. The amount of uranium lost by the sorption onto bottle walls, by precipitation, and by ultrafiltration or colloid formation was analyzed by carrying out some blank tests. The loss of uranium by the ultrafiltration was significant in the lower ionic strength(i.e., in the case of 0.001M $NaClO_4$) due to the cationic sorption effect onto the ultrafilter by a surface charge reversion. The distribution coefficient (or pseudo-colloid formation constant) for the sorption of uranium(VI) onto bentonite colloids was $10^4^{\sim}10^6$ mL/g depending upon pH and the distribution coefficient was highest in the neutral pH around 6.5.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.1
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• pp.50-55
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• 2008

In this paper, New LC VCO with $8{\sim}10.9$ GHz Band has been designed using commercial $0.35-{\mu}m$ CMOS technology. This proposed circuit is consisted of the parallel construction of the typical NMOS and PMOS cross-coupled pair which is based on the LC tank, MOS cross-coupled pair which has same tail current of complementary NMOS and PMOS, and output buffer. The designed LC VCO, which is according to proposed structure in this paper, takes a 29% improvement of the wide tuning range as 8 GHz to 10.9 GHz, and a 6.48mW of low power dissipation. Its core size is $270{\mu}m{\times}340{\mu}m$ and its phase noise is as -117dBc Hz and -137dBc Hz at 1-MHz and 10-MHz offset, respectively. FOM of the new proposed LC VCO gets -189dBc/Hz at a 1-MHz offset from a 10GHz center frequency. This design is very useful for the 10Gb/s clock generator and data recovery integrated circuit(IC) and SONET communication applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7A
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• pp.683-694
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• 2002

In this paper, a digital image compression codec using 2D DWT(Discrete Wavelet Transform) is designed using the FPGA technology for real time operation The implemented image compression codec using wavelet decomposition consists of a wavelet kernel part for wavelet filtering process, a quantizer/huffman coder for quantization and huffman encoding of wavelet coefficients, a memory controller for interface with external memories, a input interface to process image pixels from A/D converter, a output interface for reconstructing huffman codes, which has irregular bit size, into 32-bit data having regular size data, a memory-kernel buffer to arrage data for real time process, a PCI interface part, and some modules for setting timing between each modules. Since the memory mapping method which converts read process of column-direction into read process of the row-direction is used, the read process in the vertical-direction wavelet decomposition is very efficiently processed. Global operation of wavelet codec is synchronized with the field signal of A/D converter. The global hardware process pipeline operation as the unit of field and each field and each field operation is classified as decomposition levels of wavelet transform. The implemented hardware used FPGA hardware resource of 11119(45%) LAB and 28352(9％) ESB in FPGA device of APEX20KC EP20k600CB652-7 and mapped into one FPGA without additional external logic. Also it can process 33 frames(66 fields) per second, so real-time image compression is possible.

• Clean Technology
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• v.22 no.4
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• pp.308-315
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• 2016

$SiO_x/ZnO$ composites were prepared from sol-gel method for excellent cycle life characteristics. The composites were coated by PVC as a carbon precursor. ZnO removal to create a void space therein was able to buffer the volume change during charge and discharge. To determine the crystal structure and the shape of the synthesized composite, XRD, SEM, TEM analysis was performed. The carbon contents in the composites were confirmed by TGA. The pore structure and pore size distribution of the composite was measured with the BET specific surface area analysis and BJH pore size distribution. Enhanced electric conductivity by carbon addition was determined from powder resistance measurement. Electrochemical properties were measured with the AC impedance and the charge and discharge cycle life characteristics. When carbon was coated on the $SiO_x/ZnO$ sample, the electrical conductivity and the discharge capacity were increased. After removal of ZnO with HCl the surface area of the sample was increased, but the discharge capacity was decreased. $SiO_x/ZnO$ sample without acarbon coating showed very low discharge capacity, and after carbon coating the sample showed high discharge capacity. For cycle life characteristics, $C-SiO_x/ZnO$ composite (Zn : Si : C = 1 : 1 : 8) with a capacity of $815mAh\;g^{-1}$ at 50 cycle and 0.2 C has higher capacity than existing graphite-based anode materials.