• Journal of the Korean Chemical Society
• /
• v.47 no.6
• /
• pp.675-678
• /
• 2003

• Journal of the Korean Chemical Society
• /
• v.48 no.6
• /
• pp.659-662
• /
• 2004

• Bulletin of the Korean Chemical Society
• /
• v.25 no.11
• /
• pp.1671-1675
• /
• 2004

A simple method for simultaneous recovery and reuse of $OsO_4$ and alkaloid ligand in the asymmetric dihydroxylation of olefins has been developed by using macroporous alkaloid resins bearing residual vinyl groups.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.1
• /
• pp.130-132
• /
• 2006

• Journal of Electrochemical Science and Technology
• /
• v.12 no.1
• /
• pp.33-37
• /
• 2021

In electrochemical glucose sensing, the enhancement of the sensitivity and the response time is essential in developing stable and reliable sensors, especially for continuous glucose monitoring. We developed a method to increase the sensitivity and to shorten the response time for the sensing upon the appropriate addition of single wall carbon nanotube onto the osmium polymer-based hydrogel electrode. Also, the background stabilization is dramatically enhanced.

• Applied Microscopy
• /
• v.50
• /
• pp.10.1-10.6
• /
• 2020

Plant specimens for scanning electron microscopy (SEM) are commonly treated using standard protocols. Conventional fixatives consist of toxic chemicals such as glutaraldehyde, paraformaldehyde, and osmium tetroxide. In 1996, methanol fixation was reported as a rapid alternative to the standard protocols. If specimens are immersed in methanol for 30 s or longer and critical-point dried, they appear to be comparable in preservation quality to those treated with the chemical fixatives. A modified version that consists of methanol fixation and ethanol dehydration was effective at preserving the tissue morphology and dimensions. These solvent-based fixation and dehydration protocols are regarded as rapid and simple alternatives to standard protocols for SEM of plants.

• Applied Microscopy
• /
• v.47 no.2
• /
• pp.63-69
• /
• 2017

Golgi staining has been modified and developed since Camillo Golgi introduced the black reaction in 1873. This study focuses on the commonly used Golgi staining methods and presents comprehensive data regarding three Golgi staining methods along with their strong and weak points. The Golgi-Cox method uses mercuric chloride for brain tissue impregnation and is a reliable technique for analyzing the complete dendritic tree of cortical neurons. However, specimens tend to shrink during the staining steps. Recent combination of the Golgi-Cox method and immunofluorescence provides additional options for neuroscientists. Rapid Golgi staining requires osmium tetroxide for the post-fixation process. It homogenously stains whole structures of neurons and provides their detailed anatomical morphology. This staining is influenced by the age of the specimen, temperature of the laboratory, and duration of each procedure. The Golgi-Kopsch method uses formaldehyde and glutaraldehyde instead of osmium tetroxide and can be used regardless of the age of the specimen and the duration after fixation. This method is suitable for research using human brain fixed for a long time or for specimens obtained from old-aged animals. Selecting a Golgi staining protocol that is appropriate for the specimen type and research purpose is important to achieve best results.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.4
• /
• pp.934-940
• /
• 2010

The reduction of [$Os_3(CO)_{11}P(OMe)_3$] and subsequent ionic coupling of the reduced species with $[Ru({\eta}^5-C_5H_5)(CH_3CN)_3]^+$ resulted in the formation of [$Os_3(CO)_{11}P(OMe)_3(Ru({\eta}^5-C_5H_5))_2$] which can be converted to spiked tetrahedral cluster, [$HOs_3(CO)_{11}P(OMe)_3Ru_2({\eta}^5-C_5H_5)(C_5H_4)$] via the intramolecular hydrogen transfer. Due to the unavailability of a suitable single crystal, the PW91/SDD and LDA/SDD density functional methods were used to predict possible structures and the available spectroscopic information (IR, NMR) of [$Os_3(CO)_{11}P(OMe)_3(Ru({\eta}^5-C_5H_5))_2$]. The most probable geometry found by constrained search is the isomer (a2) in which the phosphite, $P(OMe)_3$, occupies an axial position on one of the two osmium atoms that is edge bridged by the $Ru(CO)_2({\eta}^5-C_5H_5)$ unit. By using the most probably geometry, the predicted infrared frequencies and $^1H$, $^{13}C$ and $^{31}P$ NMR chemical shifts of the compound are in the same range as the experimental values. For this type of complex, the LDA/SDD method is appropriate for IR predictions whereas the OPBE/IGLO-II method is appropriate for NMR predictions. The activation energy and reaction energy of the intramolecular hydrogen transfer coupled with the structural change of the transition metal framework were estimated at the PW91/SDD level to be 110.32 and -0.14 kcal/mol respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.44 no.4
• /
• pp.16-24
• /
• 2012

To characterize the coating structure, diverse methods such as mercury intrusion, nitrogen adsorption and oil absorption methods have been developed and widely employed. These indirect techniques, however, have some limitation to explain the actual coating structure. Recently microscopic observation methods have been tried for analyzing structural characteristics of coating layers. Preparation of the undamaged cross section of a coating layer is essential for obtaining high quality image for analysis. In this study, distortion-free cross-section of the coating layer was prepared using a grinding and polishing technique. The coated paper was embedded in epoxy resin and cured. After curing the resin block it was ground with abrasive papers and then polished with diamond particle suspension and nylon cloth. Polished coating layer was sufficient enough to obtain undamaged cross sectional images with scanning electron microscope under backscattered electron image mode. In addition, the SEM images allowed distinction of the coating layer components. Also S/B latex film formed between pigment particles was visualized by osmium tetroxide staining. Pore size distribution and pore orientation were evaluated by image analysis from SEM cross-sectional images.

• Applied Chemistry for Engineering
• /
• v.25 no.5
• /
• pp.437-446
• /
• 2014

The dihydroxylation reaction of allylic amines is a facile and useful synthetic method to obtain amino diol structures that are widely found in lots of biologically important natural products. This review will focus on the recent methods of both substrate-controlled and ligand-controlled dihydroxylation reactions of acyclic allylic amines. In addition, several applications of the diastereoselective dihydroxylation methods to asymmetric syntheses of natural products are presented.