• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2623-2628
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• 2013

Three di-acyl chlolide reagents, adipoyl chloride, terephthaloyl chloride and isophthaloyl chloride, were used as spacer reagents to prepare bonded type of three cellulose (3,5-dimethylphenyl)carbamate (CDMPC) chiral stationary phases (CSPs). The CDMPC CSPs were prepared using these three acid chlorides as spacer agents at the 6-position of the primary hydroxyl group on the glucose unit of cellulose regioselectively. The chiral recognition ability of the prepared CSPs for five racemates was evaluated by normal-phase high-performance liquid chromatography (HPLC) with the following mobile phases: hexane/isopropanol (IPA), hexane/IPA/tetrahydrofuran (THF) and hexane/IPA/chloroform. The result showed that these prepared CSPs can be used in THF and chloroform solutions and the chiral recognition abilities of the CSPs were improved depending on the eluents and chiral samples.

• Journal of Magnetics
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• 제16권4호
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• pp.391-397
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• 2011

An inductance measurement method for interior permanent magnet synchronous machine (IPMSM) is proposed in this paper. In this method, the motor is measured at standstill condition, and only a 3-phase voltage source, an oscilloscope and a DC voltage source are required. Depending on the deductive dq-axis voltage equations in the stationary frame of reference, the dq-axis inductances at different current magnitude and vector angle can be calculated by the measured 3-phase voltages and currents. And hence, the saturation and cross-magnetizing effect of the inductances are measurable. This paper introduces the principle equations, experiment setup, data processing, and results comparison on the concentrated-winding and distributed-winding IPMSMs.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1153-1163
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• 2005

Crown ether-based HPLC chiral stationary phases (CSPs) have been successfully utilized in the resolution of various racemic compounds containing a primary amino group. Especially, CSPs based on chiral crown ethers incorporating chiral binaphthyl unit or tartaric acid unit and based on phenolic pseudo chiral crown ethers have shown high chiral recognition efficiency. In this account paper, a review on the development of crown etherbased HPLC CSPs, their structural characteristics and applications to the resolution of racemic compounds including chiral drugs containing a primary or secondary amino group with the variation of the type and the content of mobile phase components and with the variation of the column temperature is presented.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.911-915
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• 2003

Two liquid chromatographic chiral stationary phases (CSPs) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid were successfully applied in the resolution of racemic tocainide and its analogues. In the resolution of tocainide, especially, the CSP containing N-CH₃ amide tethering groups was quite effective, showing clear baseline resolution (RS: 2.66) with reasonable enantioselectivity ( a: 1.25). Consequently, the CSP containing N-CH₃ amide tethering groups is expected to be useful to monitor the enantiomeric composition of tocainide in clinical samples. In addition, the chromatographic behaviors for the resolution of tocainide and its analogues on the two CSPs were found controllable by varying the content and the type of organic and acidic modifiers in aqueous mobile phase.

• Journal of Microbiology
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• 제45권6호
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• pp.558-565
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• 2007

Using microarray analysis, we determined those Salmonella genes induced at the entry of stationary phase, and subsequently discovered that uncharacterized yliH was induced most dramatically. We set out to establish the molecular mechanism underlying the stationary phase induction of yliH under the standard culture condition, LB with vigorous aeration, by analyzing its promoter activity in various mutant backgrounds, lacking stationary phase ${\sigma}$, $RpoS^-$, or stringent signal molecules ppGpp, ${\Delta}relA$ ${\Delta}spoT$. It was found that the stationary phase induction of yliHp was partially dependent on rpoS but entirely dependent on ppGpp. DNA sequence analysis revealed that the Salmonella yliH gene is composed of 381 base-pair nucleotides, with overall amino acid sequence revealing 76.38% amino acid identity and 88.98% similarity with Escherichia coli yliH, although no motif from data base was noted for its possible role. Recently however, it has been reported that yliH in E. coli was implicated in biofilm formation and motility by repressing these activities (Domka et al., 2006). We have constructed a mutant Salmonella deleting yliH gene by allele replacement and examined its phenotype, and found that the yliH in Salmonella more or less affects motility and adherence by enhancing these activities. The effect on biofilm formation in Salmonella was uncertain. Moreover, addition of cloned yliH of E. coli into Salmonella did not reduce motility or adherence. Taken together, it appears that the pathways implicating yliH for biofilm formation and motility in E. coli and in Salmonella are somewhat different.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.804-807
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• 2006

Bacterial serine proteases, especially those from Bacillus, have been extensively studied. Intracellular serine protease 1 (Isp1) is responsible for most of the proteolytic activity in B. subtilis. To identify Isp1 substrates and study its physiological functions, a mutant of Isp1, which has lost the enzymatic activity, was constructed. Through a GST affinity chromatographic method, several Bacillus proteins that specifically interacted with S246A mutant Isp1 protein were isolated and then identified by MALDI-TOF analysis. ClpC and elongation factor Tu (EF-Tu) were among those proteins specifically bound to mutant Isp1. In addition, several proteins involved in stationary phase adaptive response (such as RNA polymerase sigma factor, spoIIIE) were also identified. These findings led us to suggest that the major function of this serine protease, whose expression is greatly increased during the stationary phase, is to mediate transition of the cell into the stationary phase in a proper and timely manner.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1769-1774
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• 2006

A new liquid chromatographic chiral stationary phase based on (2S,3S)-O,O'-bis-(10-undecenoyl)-N,N'-bis-(3,5-dinitrobenzoyl)-2,3-diamino-1,4-butandiol was prepared starting from (2R,3R)-1,4-bis(benzyloxy)-2,3-butanediol. The new chiral stationary phase was applied to the resolution of racemic anilide derivatives of N-acetyl-a-amino acids, 1,1'-bi-2-naphthol and 3,3'-diaryl-1,1'-bi-2-naphthols. The CSP was also applied to the resolution of some chiral drugs including a diuretic, bendroflumethiazide, and non-steroidal anti-inflammatory agents such naproxen and alminoprofen. In every case, the chiral recognition efficiency of the new CSP was quite excellent.

• Bulletin of the Korean Chemical Society
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• 제26권7호
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• pp.1132-1134
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• 2005

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1809-1813
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• 2013

Sulfated ${\beta}$-cyclodextrin (SCD)-coated zirconia monolith was used as the chiral stationary phase in capillary electrochromatography for enantiomeric separation of basic chiral compounds. SCD adsorbed on the zirconia surface provided a stable chiral stationary phase in reversed-phase eluents. Retention, chiral selectivity and resolution of a set of six basic chiral compounds were measured in eluents of varying pH, composition of methanol and buffer. Optimum mobile phase condition for the separation of the compounds was found to be methanol content of 30%, buffer concentration of 30 mM and pH of 4.0.

• 생명과학회지
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• 제17권2호통권82호
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• pp.298-304
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• 2007

Salmoenella는 대표적인 intracellular pathogen으로 숙주의 면역 세포인 macrophage 내에서 살아남아 이들을 매개로 숙주의 몸 전체를 이동해 가면서 전신성 감염을 일으킨다. 살모넬라는 숙주 세포 내부의 이러한 극한 환경을 극복하기 위해서 다양한 방어 기작을 가진다. 본 연구에서는 복합적인 스트레스가 작용하는 정지기 Salmonella에서 특이적으로 발현되는 단백질에 주목하였다. 정지기 상태의 Salmonella에서 약 20 kDa의 단백질이 특이적으로 많이 발현되었으며, 세포질 분획을 통해 이 단백질이 세포질 부분에 존재함을 알 수 있었다. MALDI-TOF 분석을 통해 이 단백질이 $\b{D}NA$ binding $\b{p}rotein$ in $\b{s}tationary$ phase (Dps) 단백질임을 확인하였다. Dps 단백질은 스트레스가 주어진 상황에서 DNA에 비특이적으로 결합하여 DNA가 안정한 형태를 유지하도록 하여 스트레스로부터 염색체를 보호하는 역할을 하는 것으로 알려져 있다. 이후의 연구를 위하여 과발현하여 정제한 Dps 단백질을 토끼에 주사하여 Dps 특이적인 항체를 제조하였다. dps 발현에 영향을 미치는 조절자 단백질을 알기 위하여 다양한 S. typhimrium 돌연변이주들 내에서의 Dps 단백질양을 조사하였다.