Biomedical subjects

YJ Kim

Publications and source records attributed to YJ Kim.

14 recordsLinked to original sources

PubMed2000

Effect of solvent on aggregation and reactivity of two lithium enolates(1)

Studies with two lithium enolates show that aggregation varies from comparable to lower in dimethoxyethane (DME) compared to tetrahydrofuran (THF) but that aggregation is much higher in methyl tert-butyl ether (MTBE). Alkylation reactions, which occur dominantly with the enolate monomers, are exceptionally slow in MTBE, but even acylation reactions that can occur with aggregates are orders of magnitude slower in MTBE. These reactions apparently require additional solvation of the lithium cation, and MTBE is ineffective at such solvation.

Journal Article↗

PubMed2000

Pepper gene encoding a basic class II chitinase is inducible by pathogen and ethephon.

A chitinase cDNA clone (designated CAChi2) was isolated from the cDNA library of pepper leaves infected with Xanthomonas campestris pv. vesicatoria. The 1004-bp full-length CAChi2 cDNA encodes a basic chitinase with an N-terminal 24 amino acid signal peptide followed by a catalytic region. An analysis of its sequence indicates that CAChi2 is a class II chitinase, because it does not have chitin-binding domain and C-terminal extension sequences. The deduced amino acid sequence of CAChi2 has a high level of identity with class II chitinases from potato, tomato, tobacco and petunia. Southern analysis demonstrated that the CAChi2 chitinase is encoded by a single or two copy genes in the pepper genome. Following X. campestris pv. vesicatoria or Phytophthora capsici infection, the CAChi2 chitinase mRNA was more highly expressed in the incompatible interaction, compared to expression in the compatible interaction. Treatment with ethylene-releasing ethephon resulted in a strong accumulation of the transcripts in the leaves. In contrast, DL-beta-amino-n-butyric acid, salicylic acid and methyl jasmonate were not effective in inducing CAChi2 transcripts in pepper leaves.

Journal Article↗

PubMed2000

Behavior of the cholesteric liquid-crystal fabry-perot cavity in the bragg reflection band

In this Letter, we investigate the behavior of the cholesteric liquid-crystal Fabry-Perot cavity in the spectral range of the Bragg reflection band. We show that in this region the 2x2-Jones-matrix calculation gives a false predication. However, by the use of the 4x4-matrix method, interesting features are revealed in the resonance spectra. The resonance spectra split when lambda approximately &nmacr;P. Our experiments confirm this phenomenon. The experimental results show that the splitting occurs in a steplike fashion. This can be explained by the quantization of the pitch that occurs due to the fixed boundary conditions.

Journal Article↗

PubMed1996