• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.409.1-409.1
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• 2002

For the development of a biocompatible nano-scale drug carrier. hydrophilic polysaccharide pullulan was hydrophobized by the conjugation with fatty acid. The synthesized polymers were characterized by the measurements of fourier transform infrared (FT -IR) spectroscopy and 1H -nuclear magnetic resonance (NMR) spectroscopy. In aqueous solution. hydrophobically modified puliulan was self-assembled and structured into the core-shell type nanoparticles. (omitted)

• Restorative Dentistry and Endodontics
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• 제32권5호
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• pp.445-458
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• 2007

단일과정 접착제를 이용함에 있어 복합레진과의 부적합성을 개선하고자 중간레진이 결합에 영향을 미칠 것으로 사료된다. Experimental single step system (Bisco Ltd., Schaumburg, IL)을 대조군으로 하고 6종의 중간레진을 접착제의 중합여부, 복합레진의 광중합-자가중합 여부로 분류하였다. 상아질에 대한 광중합 또는 자가중합형 복합레진의 결합강도를 측정하고 접착계면에 대한 투과전자현미경 관찰하여 다음과 같은 결론을 얻었다. 1. 중간레진의 적용은 광중합형 복합레진의 결합강도를 증가시키지 않았다. 2. 자가중합형 복합레진의 결합강도는 중간레진을 적용할 경우 증가하였다. 3. 중간레진의 적용 전 접착제의 중합여부는 결합강도의 변화에 영향을 미치지 않았다. 4. 중간레진이 친수성일 때 소수성 중간레진을 적용할 때 보다 높은 결합강도를 나타냈으나 통계적 유의차는 없었다. 광중합형 복합레진의 수복 시 단일과정 접착제를 사용하는 것은 초기 결합강도에 영향을 미치지 않으며, 자가중합형 복합레진을 단일과정 접착제와 사용할 때는 접착층의 투과도를 감소시키는 소수성의 중간레진을 적용하여 부적합성을 해소할 수 있을 것이다.

• 한국염색가공학회지
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• 제9권6호
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• pp.79-86
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• 1997

The microcapsule for thermochromism is based on the polymerization reaction between epoxy resin and amine curing agent. The preparation process of microcapsule is based on dissolving or dispersing a hydrophobic core materials[one-dye-black(OBD), bis-phenol A(BPA), cetyl alcohol] in an aqueous solution of gelatin, epoxy resin and isophorondiamine(IPDA) ; the gelatin and IPDA used as a dispersion stabilizer and an hardening agent, respectively. The structures of epoxy resin and microcapsule materials have been analyzed by FT-IR and UV/Vis spectra. The mean diameter and size distribution of microcapsule are 1.46~1.75${\mu}{\textrm}{m}$ and 1.42, respectively. The DSC thermograms of microcapsules indicated 2 kinds of endothermic peaks at 47 and 322$^{\circ}C$. This is possibly corresponding to the melting peak of core material and wall meterial. These microcapsules are applied to the fabric by printing. Complex finished fabric showed a good wear resistance on rubbing test and the print pattern to the cotton fabric showed a reversible thermochromism ; ${\mu}_{max}$ are 580 nm below 4$0^{\circ}C$ and 276.5nm above 4$0^{\circ}C$ in ethanol/water(2/8), respectively.

• 폴리머
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• 제28권2호
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• pp.154-161
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• 2004

폴리(4-비닐피리딘)의 질소 원자에 메틸기를 부착시켜 4차아민화시켜서 부분적으로 개질된 폴리(4-비닐피리딘)을 얻었고, 부분 개질된 폴리(4-비닐피리딘)의 구조를 수용액상에서 레이저 광산란 및 형광법 등을 이용하여 조사한 결과, 자기 응집현상에 의하여 핵-껍질 구조를 가지고 있는 것으로 나타났다. 즉 사슬의 소수성 부분은 상호작용에 의하여 중심부에 모여있고, 4차화된 아민의 양전하를 가진 친수성 부분은 바깥 껍질을 형성하고 있었다. 이 고분자 수용액에 음이온 계면활성제인, 도데실 황산 소듐을 첨가하면 이들 사이에 임계 응집 농도가 존재하며, 이 임계 응집 농도는 특히 NaCl 농도 0.1 M 이상에서는 급격히 감소하는 경향을 보여주었다. 또한 계면활성제의 첨가에 따라 생성된 고분자-계면활성제의 복합 응집체의 입자크기 변화 등을 동적 광산란으로 측정 분석하였다.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.200-206
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• 2007

Pharmacophore models for lymphocyte-specific protein tyrosine kinase (P56 LCK) were developed using CATALYST HypoGen with a training set comprising of 25 different P56 LCK inhibitors. The best quantitative pharmacophore hypothesis comprises of one hydrogen bond acceptor, one hydrogen bond donor, one hydrophobic aliphatic and one ring aromatic features with correlation coefficient of 0.941, root mean square deviation (RMSD) of 0.933 and cost difference (null cost-total cost) of 66.23. The pharmacophore model was validated by two methods and the validated model was further used to search databases for new compounds with good estimated LCK inhibitory activity. These compounds were evaluated for their binding properties at the active site by molecular docking studies using GOLD software. The compounds with good estimated activity and docking scores were evaluated for physiological properties based on Lipinski's rules. Finally 68 compounds satisfied all the properties required to be a successful inhibitor candidate.

• 한국안전학회지
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• 제34권3호
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• pp.28-35
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• 2019

Dry water is a core-shell structured powder which comprises a very fine water core covered with hydrophobic silica particles. Recently, the dry water has attracted attention as a new type of fire extinguishing agents. However, characteristics of the dry water as a fire extinguishing agent have not been revealed until now. To our best knowledge, this is the first work to uncover effects of particle size of the dry water on the fire extinguishing performance. Pristine dry water, which has heterogeneous particle size distribution, was carefully separated by sieving method into three fractions which were a small size (ca. $110{\mu}m$) fraction, a medium size (ca. $220{\mu}m$) fraction and a large size (ca. $400{\mu}m$) fraction. Microscopic observations confirmed the effective separation of dry water's particle size. In extinguishing tests of wood cribs fire, the medium size dry water showed most excellent fire extinguishing performance, as compared to other dry waters having small (ca. $110{\mu}m$) and large (ca. $400{\mu}m$) particle size. The good performance of the medium size (ca. $220{\mu}m$) dry water may be attributed to the balance between cooling effect of the water core and smothering effect of the silica particles. It is also revealed that small size dry water has poor flowability than large size dry water.

• Bulletin of the Korean Chemical Society
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• 제19권9호
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• pp.962-967
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• 1998

Block copolymers consisting of poly(rbenzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part were synthesized and characterized. Polymeric micelles of the block copolymers (abbreviated GEG) were prepared by a dialysis method. The GEG block copolymers were associated in water to form polymeric micelles, and the critical micelle concentration (CMC) values of the block copolymers decreased with increasing PBLG chain length in the block copolymers. Transmission electron microscopy (TEM) observations revealed polymeric micelles of spherical shapes. From dynamic light scattering (DLS) study, sizes of polymeric micelles of GEG-1, GEG-2, and GEG-3 copolymer were 106.5±59.2 nm, 79.4±46.0 nm, and 37.9±13.3 nm, respectively. The drug loading contents of GEG-1, GEG-2 and GEG-3 polymeric micelles were 12.6, 11.9, and 11.0 wt %, respectively. These results indicated that the drugloading contents were dependent on PBLG chain length in the copolymer; the longer the PBLG chain length, the more the drug-loading contents. Release of norfloxacin (NFX) from the nanoparticles was slower in higher loading contents of NFX than in lower loading contents due to the hydrophobic interaction between PBLG core and NFX.

• Macromolecular Research
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• 제12권6호
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• pp.573-580
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• 2004

To prepare chitosan-based polymeric amphiphiles that can form nanosized core-shell structures (nanopar­ticles) in aqueous milieu, chitosan oligosaccharides (COSs) were modified chemically with hydrophobic cholesterol groups. The physicochemical properties of the hydrophobized COSs (COSCs) were investigated by using dynamic light scattering and fluorescence spectroscopy. The feasibility of applying the COSCs to biomedical applications was investigated by introducing them into a gene delivery system. The COSCs formed nanosized self-aggregates in aqueous environments. Furthermore, the physicochemical properties of the COSC nanoparticles were closely related to the molecular weights of the COSs and the number of hydrophobic groups per COS chain. The critical aggregation concentration values decreased upon increasing the hydrophobicity of the COSCs. The COSCs effi­ciently condensed plasmid DNA into nanosized ion-complexes, in contrast to the effect of the unmodified COSs. An investigation of gene condensation, performed using a gel retardation assay, revealed that $COS6(M_n=6,040 Da)$ containing $5\%$ of cholesteryl chloroformate (COS6C5) formed a stable DNA complex at a COS6C5/DNA weight ratio of 2. In contrast, COS6, the unmodified COS, failed to form a stable COS/DNA complex even at an elevated weight ratio of 8. Furthermore, the COS6C5/DNA complex enhanced the in vitro transfection efficiency on Human embryonic kidney 293 cells by over 100 and 3 times those of COS6 and poly(L-lysine), respectively. Therefore, hydrophobized chitosan oligosaccharide can be considered as an efficient gene carrier for gene delivery systems.

• Journal of Microbiology and Biotechnology
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• 제13권4호
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• pp.564-570
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• 2003

The antibacterial mechanism of enterobacter Salmonella typhimurium was studied. The rfa (Waa) gene cluster of S. typhimurium encodes the core oligosaccharide biosynthesis of lipopolysaccharide (LPS). Among the rfa gene cluster, we recently cloned the rfaE gene, which is involved in ADP-L-glycero-D-manno-heptose biosynthesis. The rfaE mutant synthesizes heptose-deficient LPS, which consists of only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), thus making an incomplete LPS and a rough phenotype mutant. S. typhimurium deep-rough mutants with the heptose region of the inner core show a reduced growth rate, sensitivity to high temperature, and hypersensitivity to hydrophobic antibiotics such as baicalin isolated from the medicinal herb of Scutellaria baicalensis Georgi. Thus, in this study, the cloned rfaE gene was added to the S. typhimurium rfaE mutant strain SL1102 (rfaE543), which makes heptose-deficient LPS and has a deep-rough phenotype. The complementation created a smooth phenotype in the SL1102 strain. The sensitivity of SL1102 to bacteriophages was also recovered to that of wild-type strain, indicating that LPS is used as the receptor for bacteriophage infection. The permeability barrier of SL1102 to hydrophobic antibiotics such as novobiocin and baicalin was restored to that of the wild-type, suggesting that antibiotic resistance of the wild-type strain is highly correlated with their LPS. Through an agar diffusion assay, the growth-inhibition activity of baicalin was fully observed in the mutant SL1102 strain. However, only a half of the inhibitory activity was detected in the rfaE complemented SL1102 strain. Furthermore, the LPS produced by the rfaE-complemented SL1102 strain was indistinguishable from LPS biosynthesis of smooth strains.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3333-3340
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• 2010

A three dimensional pharmacophore model was generated for the molecules which are responsible for anti-inflammatory activities targeting Interleukin-2 inducible tyrosine kinase (Itk). 16 structurally diverse molecules were selected as training set to generate the hypotheses using Discovery Studio v2.1. The best hypothesis, Hypo1, comprises two hydrogen bond acceptor (HBA), one hydrophobic aromatic (HA), one ring aromatic (RA) and shows high cost difference (63.71), high correlation coefficient (0.97) as well as low RMS deviation (0.81). Hypo1 has been further validated toward a test set, decoy set and Fischer's randomization method. Furthermore, Hypo1 was used to screen NCI and Maybridge databases. Finally, 2 hit molecules were identified as potential leads against Itk, which may be useful for future drug development.