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Biomedical subjects

SY Lee

Publications and source records attributed to SY Lee.

At least 19 recordsLinked to original sources
PubMed2000

Preparation of alkyl (R)-(-)-3-hydroxybutyrate by acidic alcoholysis of poly-(R)-(-)-3-hydroxybutyrate.

An efficient method for the preparation of optically active alkyl (R)-(-)-3-hydroxybutyrates by chemical depolymerization of biopolymer, poly-(R)-(-)-(3-hydroxybutyrate), was established. This method consists of simple recovery of poly-(R)-(-)-(3-hydroxybutyrate) from bacterial cells followed by acidic alcoholysis. When poly-(R)-(-)-(3-hydroxybutyrate) was purified by a simple digestion method that used 0.2 N sodium hydroxide, alkyl (R)-(-)-hydroxybutyrates were most efficiently produced by alcoholysis with anhydrous hydrochloric acid.

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PubMed2000

Efficient approach to 4-oxo-2-alkenylphosphonates via regiospecific friedel-crafts acylation

Treatment of allylic and vinylic phosphonates with excess LiHMDS, followed by addition of chlorotrimethylsilane, afforded alpha- and gamma- silylated allylic phosphonate mixtures. Without separation, these mixtures underwent the Friedel-Crafts reaction and base-promoted isomerization to give 4-oxo-2-alkenylphosphonates, which can serve as building blocks for the construction of polyethylenic chains.

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PubMed2000

Molecular cloning of a soybean class III beta-1,3-glucanase gene that is regulated both developmentally and in response to pathogen infection.

We isolated and characterized a soybean gene (SGN1) encoding a basic beta-1,3-glucanase that is a plant class III isoform of beta-1,3-glucanase. The deduced amino acid sequence of the SGN1 gene is similar to that of the PR-Q'b gene, the basic class III beta-1,3-glucanase of tomato. Based on RNA blot hybridization, SGN1 gene expression was detected in all tissues of 4-day old seedlings, but it was present only in root tissue of 30-day old plants. GUS expression analysis carried out in transgenic tobacco plants harboring a SGN1::GUS reporter gene revealed the same expression pattern. Furthermore, the expression of SGN1 was strongly induced by a variety of defense-related signals, such as treatment with H(2)O(2), wounding, or treatment with fungal elicitor prepared from Phytophthora spp as well as inoculation with Pseudomonas syringae. However, the expression level of SGN1 was hardly induced with jasmonate, ethephon and salicylate. Overall the results suggest that the SGN1 may play a role in both plant development and plant defense against pathogen attack.

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PubMed2000

Observation of a hybrid spin resonance

A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchrotron (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This "hybrid" spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors.

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PubMed1999

Optical CDMA system using bacteriorhodopsin for optical data storage

An optical CDMA (code division multiple access) system for the optical data storage using bacteriorhodopsin (BR) is reported as an application of the BR materials. The desired signal of multiple input can be recorded and reconstructed by use of orthogonal codes. An experimental setup is proposed and demonstrated.

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