• Bulletin of the Korean Chemical Society
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• 제18권5호
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• pp.463-464
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• 1997

• 대한화학회지
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• 제42권2호
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• pp.161-171
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• 1998

알켄-오존 반응에서 생성된 중간 생성물로써 primary ozonide (POZ),secondary ozonide (SOZ)그리고 carbonyl oxide의 분자구조, vibrational frequencies그리고 infrared(IR)스펙트럼의 세기 등에 대한 이론적 연구를 high level ab initio 양자역학적 방법(CISD,CCSD)을 사용하여 수행하였다. 일반적으로, polarization function은 결합각과 결합길이를 감소시키는 경향을 보였고 반면, electron correlation effect는 결합길이와 결합각을 약간 증가시키는 경향을 보이고 있다. Carbonyl oxide의 분자구조는 zwitterionic form이 diradical form보다 더 안정한 것으로 예측되었으며, 두 형태의 에너지는 차이는 TZ2P CISD level에서 약 22.4 kcal/mol인 것으로 계산되었다. 또한, POZ과 SOZ의 분자구조 및 harmonic vibrational frequencies들을 실험결과와 비교 분석하였으며 IR세기에 근거하여 각 vibrational mode를 assign 하였다.

• Journal of Microbiology and Biotechnology
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• 제25권5호
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• pp.704-708
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• 2015

For the analysis of multiple-reaction intermediates for long-chain dicarboxylic acid biotransformation, simple and reproducible methods of extraction and derivatization were developed on the basis of gas chromatography with flame ionization detector (GC-FID) instead of mass spectrometry. In the derivatization step, change of the ratio of pyridine to MSTFA from 1:3 to 9:1 resulted in higher peak intensity (p = 0.021) and reproducibility (0.6%CV) when analyzing 32 g/l ricinoleic acid (RA). Extraction of RA and ω-hydroxyundec-9-enoic acid with water containing 100 mM Tween 80 showed 90.4-99.9% relative extraction efficiency and 2-7%CV compared with those with hydrophobic ethyl acetate. In conclusion, reduction of the pyridine content and change of the extraction solvent to water with Tween 80 provided compatible derivatization and extraction methods to GC-FID-based analysis of longchain carboxylic acids.

• 동의신경정신과학회지
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• 제8권2호
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• pp.13-24
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• 1997

This study was done to know the effects of the water extracts of Gyogamdan(GGD) on the function of macrophages, the most important cells of the innate immune system, and the rosette forming ability of splenocytes in the mouse under stress. The effects of GGD on the immunosuppression induced by noise stress are as follows. 1. Administration of GGD water extracts normalized the bo요 weight which might be decreased by noise stress. 2. Administration of GGD water extracts increased the production of the such reactive oxygen intermediates as superoxide and hydrogen peroxide from macrophsges in vivo & in vitro which were decreased by noise stress. 3. Administration of GGS water extracts did not affect the production of reactive nitrogen intermediates. 4. Administration of GGD water extracts increased the rosette forming ability of splenocytes which was decreased by noise stress. The above effects of GGD might be useful for the treatment of stress-induced infections diseases which could be caused by the suppression of immune responeses which are initiated by the functions of macrophages of the innate immune system.

• BMB Reports
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• 제32권6호
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• pp.521-528
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• 1999

The folding of recombinant hepatitis B virus X-protein (rHBx) solubilized from Escherichia coli inclusion bodies was investigated. By sequential dialysis of urea, rHBx was folded into its native structure, which was demonstrated by the efficacy of its transcriptional activation of the adenovirus major late promoter (MLP), fluorescence spectroscopy, and circular dichroism (CD) analysis. The decrease in CD values at 220 nm and a corresponding blue shift of the intrinsic fluorescence emission confirmed the ability of rHBx to refold in lower concentrations of urea, yielding the active protein. Equilibrium and kinetic studies of the refolding of rHBx were carried out by tryptophan fluorescence measurements. From the biphasic nature of the fluorescence curves, the existence of stable intermediate states in the renaturation process was inferred. Reverse phase-high performance liquid chromatography (RP-HPLC) analysis further demonstrated the existence of these intermediates and their apparent compactness.

• 대한예방한의학회지
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• 제19권2호
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• pp.123-133
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• 2015

The new formular for herbal medicine-safety classification in terms of evidence-based medicine was developed and applied to evaluate various herbal medicines in the previous study. This study is aimed to evaluate the frequently-used herbal medicines inducing toxic metabolites or reactive intermediates(RI), such as Ligusticum wallichii Franch, Angelica sinensis, Glycyrrhizae Radix, Rehmanniae Radix, based on 6 safety grades calculated from human equivalent dose(HED)-based MOS(margin of safety). HED-based MOS can be explained as the ratio of theoretical ALD(approximate lethal dose) of human as $LD_1$(lethal dose of 1%)/ clinical maximum dose as $ED_{99}$(Effective dose of 99%). The herbal medicine showing the ratio less than 1 belongs to Class 1, but the herbal medicine showing the ratio more than 500 belongs to Class 6 with the lowest toxicity. As a result, they were evaluated as class 2 for Angelica sinensis and Glycyrrhizae Radix, class 3 for Ligusticum wallichii Franch and Rehmanniae Radix. These resultant grades for 4 herbal medicines were lower than the grade expected under consideration that these herbal medicines are used very frequently in oriental clinics. These low grades would be due to their ingredients which is biotransformed to toxic metabolites.

• Journal of Microbiology and Biotechnology
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• 제16권7호
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• pp.1158-1162
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• 2006

The glyoxylate cycle can conserve carbons and adequately supply tricarboxylic acid (TCA) cycle intermediates for biosynthesis when microorganisms grow on $C_{2}$ carbon sources. It has been reported that isocitrate lyase (ICL1), a key enzyme of the glyoxylate cycle, is highly induced when Magnaporthe grisea, the causal agent of rice blast, infects its host. Therefore, the glyoxylate cycle is considered as a new target for antifungal agents. A 1.6-kb DNA fragment encoding the ICL1 from M. grisea KJ201 was amplified by PCR, cloned into a vector providing His-tag at the N-terminus, expressed in Escherichia coli, and purified using Ni-NTA affinity chromatography. The molecular mass of the purified ICL1 was approximately 60 kDa, as determined by SDS-PAGE. The ICL1 inhibitory effects of TCA cycle intermediates and their analogs were investigated. Among them, 3-nitropropionate was found to be the strongest inhibitor with an $IC_{50}$ value of $11.0{\mu}g/ml$. 3-Nitropropionate inhibited the appressorium development in M. grisea at the ${\mu}M$ level, whereas conidia germination remained unaffected. This compound also inhibited the mycelial growth of the fungus on minimal medium containing acetate as a $C_{2}$ carbon source. These results suggest that ICL1 plays a crucial role in appressorium formation of M. grisea and is a new target for the control of phytopathogenic fungal infection.

• 농약과학회지
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• 제5권1호
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• pp.24-29
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• 2001

은행잎함유 살충성분인 bilobalide의 활성부위를 조사하기 위해 bilobalide를 가수분해 및 산화를 시킨 후 구조를 확인하고 살충활성을 검정하였다. 분해물의 분석 결과, 염기에 의한 가수분해물은 cyclopentenone 계열의 화합물로 밝혀졌고, 산화물은 trilactone 형태를 유지한 sesquiterpene 구조로써 dehydration된 형태로 추정되었다. 분해물의 살충활성을 검정한 결과, 살충력의 크기는 bilobalide, monoacetyl 유도체, ginkgolide C, 산화분해물, diacetyl 유도체, 가수분해물의 순으로 감소하여 bilobalide의 살충력을 나타내는데에는 trilactone의 구조를 유지하는 것이 중요한 것으로 나타났다.

• 한국응용과학기술학회지
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• 제23권2호
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• pp.99-109
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• 2006

In order to obtain the maximum flame retardancy as well as the minimum deterioration of physical properties of PU flame-retardant coatings, chlorine and phosphorus functional groups were introduced into the pre-polymer of modified polyesters. In the first step, the tetramethylene bis(orthophosphate) (TBOP) and neohexanediol dichloroacetate (DCA-adduct) intermediates were synthesized. In the second step, 1,4-butanediol and adipic acid monomers were polymerized with the two kinds of intermediates to obtain copolymers. The modified polyesters containing chlorine and phosphorus (ATBA-10C, -20C, and -30C) were synthesized by adjusting that the content of phosphorus compound was fixed as 2wt% and the contents of chlorine compound (dichloroacetic acid) were varied as 10, 20, and 30wt%. Average molecular weight and polydispersity index of the preparation of ATBAs were decreased with increasing DCA content because of the increase in hydroxyl group that retards reaction.

• 한국환경과학회지
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• 제16권4호
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• pp.433-440
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• 2007

The photodegradation and by-products of the gaseous toluene with $TiO_2$ (P25) and short-wavelength UV ($UV_{254+185nm}$) radiation were studied. The toluene was decomposed and mineralized efficiently owed to the synergistic effect of photochemical oxidation in the gas phase and photocatalytic oxidation on the $TiO_2$ surface. The toluene by the $UV_{254+185nm}$ photoirradiated $TiO_2$ were mainly mineralized $CO_2$ and CO, but some water-soluble organic intermediates were also formed under severe reaction conditions. The ozone and secondary organic aerosol were produced as undesirable by-products. It was found that wet scrubber was useful as post-treatment to remove water-soluble organic intermediates. Excess ozone could be easily removed by means of a $MnO_2$ ozone-decomposition catalyst. It was also observed that the $MnO_2$ catalyst could decompose organic compounds by using oxygen reactive species formed in process of ozone decomposition.