• Macromolecular Research
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• v.17 no.9
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• pp.638-645
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• 2009

We report the effect of the amount of the mesoporous material, SBA-15, on the basic traits of fully aliphatic polyimides (API). For this purpose, water soluble, fully aliphatic poly(amic acid) triethyl amine salts ($PAA_{(s)}$) were prepared and mixed with various amounts of SBA-15. Fully aliphatic polyimide hybrid composites containing the SBA 15-type mesoporous silica were synthesized successfully from bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and alicyclic diamine, 4,4'-methylene bis(2-methylcyclohexylamine). The structure of the hybrid composites was confirmed by IR spectroscopic analysis. Scanning electron microscopy revealed the morphology of the compounds. The hybrid composites exhibited good thermal stability, reasonable transparency, and a low dielectric constant.

• Archives of Pharmacal Research
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• v.26 no.2
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• pp.173-181
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• 2003

A polymeric micelle drug delivery system was developed to enhance the solubility of poorly-water soluble drug, biphenyl dimethyl dicarboxylate, DDB. The block copolymers consisting of poly(D,L-lactide) (PLA) as the hydrophobic segment and methoxy poly(ethylene glycol) (mPEG) as the hydrophilic segment were synthesized and characterized by NMR, DSC and MALDI-TOF mass spectroscopy. The size of the polymeric micelles measured by dynamic light scattering showed a narrow monodisperse size distribution with the average diameter less than 50 nm. The MW of mPEG-PLA, 3000 (MW of mPEG, 2 K; MW of PLA, 1K), and the presence of hydrophilic and hydrophobic segments on the polymeric micelles were confirmed by MALDI-TOF mass spectroscopy and NMR, respectively. Polymeric micelle solutions of DDB were prepared by three different methods, i.e. the matrix method, emulsion method and dialysis method. In the matrix method, DDB solubility was reached to 13.29 mg/mL. The mPEG-PLA 2K-1K micelle system was compared with the poloxamer 407 micelle system for their critical micelle concentration, micelle size, solubilizing capacity, stability in dilution and physical state. DDB loaded-polymeric micelles prepared by the matrix method showed a significantly increased aqueous solubility (＞5000 fold over intrinsic solubility) and were found to be superior to the poloxamer 407 micelles as a drug carrier.

• Journal of Ginseng Research
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• v.22 no.2
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• pp.82-90
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• 1998

In order to stabilize the price of fresh ginseng by extension of seasonal variation and marketing structure, and to reduce the cost of production by works of intensive and short term, studies were carried out. As fresh ginseng of 4 years old by the MA and CA was stored for 12 week at 4$^{\circ}C$, samples were collected after every 1, 2, 3, 4, 6, 8, 12 weeks for processing red ginseng. Color and Sensual characteristics on ginseng steamed red for the quality evaluation are summarized as follows. For the time course of storage with red ginseng, which was processed from fresh one after various treatments, L and b values were decreased, however a value was increased. In particular, absorbance was step-wisely increased. Turbidity was somewhat increased, and non-treatment of preservative were shown 2 times higher of absorbance. Extraction ratio of ethanol-soluble extractives slightly increased by the preservation methods, and as storage period was passed. CA storage and preservative treat merit versus MA and non-preservative treatment gave much stability in ginseng quality. In the sensual characters, sour taste and sweet taste were increased, but fresh taste and rice scorched taste were decreased. Bitter taste was not much changed until end of storage. CA was shown smaller differences than MA in the pH change. Addition of preservative extended the storage time.

• Journal of Microbiology
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• v.43 no.6
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• pp.561-568
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• 2005

A newly-isolated thermophilic strain of the zygomycete fungus Rhizomucor pusillus 13.36 produced highly active dextrinogenic and saccharogenic enzymes. Cassava pulp was a good alternative substrate for amylase production. Dextrinogenic and saccharogenic amylases exhibited optimum activities at a pH of 4.0-4.5 and 5.0 respectively and at a temperature of $75^{\circ}C$. The enzymes were highly thermostable, with no detectable loss of saccharogenic or dextrinogenic activity after 1 hand 6 h at $60^{\circ}C$, respectively. The saccharogenic activity was inhibited by $Ca^{2+}$ while the dextrinogenic was indifferent to this ion. Both activities were inhibited by $Fe^{2+}\;and\;Cu^{2+}$ Hydrolysis of soluble starch by the crude enzyme yielded $66\%$ glucose, $19.5\%$ maltose, $7.7\%$ maltotriose and $6.6\%$ oligosaccharides.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.4
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• pp.609-617
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• 1998

A microorganism capable of producing high level of extracellular cyclodextrin glucanotransferase(EC 2.4.1.19 ; CGTase) was isolated from Kimchi. 2-O-$\alpha$-D-glucopyranosyl L-ascorbic acid(AA-2G) was synthesized by transglycosylation reaction of CGTase using starch as a donor and L-ascorbic acid as an acceptor. The isolated strain S-6 was identified as Bacillus sp. S-6. The maximal CGTase production was observed in a medium containing 0.5% soluble starch, 1% yeast extract, 1% NaCO3, 0.1% K2HPO4, and 0.02% MgSO4 with initial pH 8.0. The strain was cultured at 37$^{\circ}C$ for 40 hr with reciprocal shaking. Using the culture supernatant as crude enzyme, the optimal pH and temperature of the CGTase activity of this strain were 7.0 and 4$0^{\circ}C$. In the effects of pH and temperature on the stability of the enzyme, the enzyme was stable in the range of pH 6.0~10.0 and up to 45$^{\circ}C$, respectively.

• YAKHAK HOEJI
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• v.46 no.2
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• pp.102-107
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• 2002

The particle size of medicinal materials is an important physical property which affects the pharmaceutical behaviors such as dissolution, chemical stability, compressibility and bioavailability of solid dosage forms. The size reduction of raw pharmaceutical powder is needed to formulize insoluble drugs or slightly soluble drugs and to improve the pharmaceutical properties such as the solubility, the pharmaceutical mixing and the dispersion. The objective of the present study is to evaluate the grinding characteristics of ursodeoxycholic acid(UDCA) as a model of insoluble drugs. The effects of the grinding time and the amount of additive on particle size distribution of ground UDCA were investigated. Grinding of insoluble drug, UDCA and a series of dry co-grinding experiments of UDCA with sodium lauryl sulfate(SLS) as an additive were carried out using a planetary ball mill. It was measured that the median diameter and the particle size distribution of ground products with grinding UDCA and additive SLS by Mastersizer. As a result of co-grinding of UDCA and SLS, the particle size of co-grinding products was decreased more than single grinding one. However, it was observed that co-grinding products were reaggregated to larger particles after 120 min.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.162-167
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• 2015

To investigate the effect of fluoro groups substitution on poly(p-phenylenevinylene) derivatives, poly(2,3,5,6- tetrafluoro-p-phenylenevinylene-alt-N-ethylhexyl-3,6-carbazolevinylene), PCTF-PPV, and poly[2,3,5,6-tetrafluoro-p-phenylenevinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene], PMTF-PPV, were synthesized by the well-known Wittig condensation polymerization process. To compare the influences of fluoro groups, no fluoro groups containing model polymers, poly(p-phenylenevinylene-alt-N-ethylhexyl-3,6-carbazolevinylene), PCPPPV and poly[p-phenylenevinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene], p-PMEH-PPV, were also synthesized. The resulting polymers were completely soluble in common organic solvents and exhibited good thermal stability up to 300℃. The polymers showed UV-visible absorbance and photoluminescence (PL) in the ranges of 259~452 nm and 500~580 nm, respectively. The tetrafluorophenyl containing PCTF-PPV and PMTF-PPV showed relatively red-shifted PL peaks at 521 nm and 580 nm, respectively, compared to that of non-fluoro groups containing polymers (PCP-PPV: 500 nm and p-PMEH-PPV: 539 nm). The single-layer light-emitting diode was fabricated in a configuration of ITO/polymer/Al. Electroluminescene (EL) emissions of PCP-PPV, PCTF-PPV, p-PMEH-PPV and PMTF-PPV were shown at 507, 524, 556, and 616 nm, respectively.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.2031-2036
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• 2012

Melt copolymerization reactions of several bis(diethylamino)silane derivatives, bis(diethylamino)methylphenylsilane, bis(diethylamino)methyloctylsilane, 1,2-bis(diethylamino)tetramethyldisilane, and 1,3-bis(diethylamino) tetramethyldisiloxane, with 2,7-dihydroxyfluoren-9-one were carried out to yield poly[oxy(2,7-fluoren- 9-onenylene)oxy(diorganosilylene)]s bearing the fluoren-9-one fluorescent aromatic group in the polymer main chain: poly[oxy(2,7-fluoren-9-onenylene)oxy(methylphenylsilylene)], poly[oxy(2,7-fluoren-9-onenylene) oxy(methyloctylsilylene)], poly[oxy(2,7-fluoren-9-onenylene)oxy(tetramethyldisilylene)], and poly[oxy- (2,7-fluoren-9-onenylene)oxy(tetramethyldisiloxanylene)]. These polymeric materials are soluble in common organic solvents such as $CHCl_3$ and THF. FTIR spectra of all the materials reveal characteristic Si-O-C stretching frequencies at 1012-1018 $cm^{-1}$. In the THF solution, the prepared materials show strong maximum absorption peaks at 258-270 nm, strong maximum excitation peaks at 260-280 nm, and strong maximum fluorescence emission bands at 310-420 nm. TGA thermograms suggest that most of the polymers are essentially stable to $200^{\circ}C$ without any weight loss and up to $300^{\circ}C$ with only a weight loss of less than 5% in nitrogen.

• Journal of the Korean Chemical Society
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• v.57 no.5
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• pp.574-590
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• 2013

A new solid complexes of Ti(IV), Y(III) and Ce(IV) have been synthesized with ofloxacin. The formulae and structure of the complexes have been proposed in the light of analytical, spectral ($^1H$ NMR, IR and UV-Visible), magnetic, molar conductivities and thermal studies. The complexes are soluble in DMSO-$d_6$ and DMF. The measured molar conductance values indicate that, the three complexes are electrolyte in nature. The results support the formation of the complexes and indicated that ofloxacin reacts as a bidentate ligand chelate to the metal ion through the pyridone oxygen and one carboxylato oxygen. The kinetic parameters of thermogravimetric and its differential have been evaluated by using Coats Redfern (CR) and Horowitz-Metzeger (HM) methods. The thermodynamic data reflect the thermal stability for all complexes. The metal- ligand binding of the Ti(IV), Y(III) and Ce(IV) complexes is predicted using density funcational theory at the B3LYP-CEP-31G level of theory and total energy, dipole moment estimation of different Ti(IV), Y(III) and Ce(IV) ofloxacin structures. The biological activities of the ofloxacin, inorganic salts and their metal complexes were assayed against different bacterial species.

• Journal of Information Display
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• v.6 no.4
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• pp.1-5
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• 2005

Perylene-based pyrrolopyrone derivative (PPD) was synthesized via condensation reaction with perylenetetracarboxylic dianhydride and 1,2-phenylenediarnine as n-type channel material. The structure of PPD was characterized by spectroscopic methods such FT-IR and $^1H$-NMR. PPD exhibited high thermal stability ($T_{d5wt%}: 560^{\circ}C$) and was found to be soluble only in protonic solvents with high acidity such as methane sulfonic acid and trifluoroacetic acid. The PPD solution showed maximum absorption and emission at 601 and 628 nm, respectively. Thin film transistors were fabricated by vacuum deposition and solution casting method. The electron mobilities of the devices were achieved as high as $0.17{\times}10^{-6}cm^2/Vs$ for vacuum deposited device and $0.4{\times}10^{-6}cm^2/Vs$ for spin coated device, respectively.