• Journal of Microbiology and Biotechnology
• /
• v.19 no.1
• /
• pp.51-54
• /
• 2009

Myxobacteria, Gram-negative soil bacteria, are a well-known producer of bioactive secondary metabolites. Therefore, this study presents a methodological approach for the high-throughput screening of secondary metabolites from 4 wild-type Myxococcus xanthus strains. First, electrospray ionization mass spectrometry (ESI-MS) was performed using extracellular crude extracts. As a result, 22 metabolite peaks were detected, and the metabolite profiling was then conducted using the m/z value, retention time, and MS/MS fragmentation pattern analyses. Among the peaks, one unknown compound peak was identified as analogous to the myxalamid A, B, and C series. An analysis of the tandem mass spectrometric fragmentation patterns and HR-MS identified myxalamid K as a new compound derived from M. xanthus. In conclusion, LC-MS/MS-based chemical screening of diverse secondary metabolites would appear to be an effective approach for discovering unknown microbial secondary metabolites.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.156-156
• /
• 2017

In this work, analysis of biocompatible TiO2 oxide multilayer by the XPS depth profiling was researched. the manufacture of the TiO2 barrier-type multilayer was accurately performed in a mixed electrolyte containing HAp, Pd, and Ag nanoparticles. The temperature of the solution was kept at approximatively $32^{\circ}C$ and was regularly rotated by a magnetic stirring rod in order to increase the ionic diffusion rate. The manufactured specimens were carefully analyzed by XPS depth profile to investigate the result of chemical bonding behaviors. From the analysis of chemical states of the TiO2 oxide multilayer using XPS, the peaks are showed with the typical signal of Ti oxide at 459.1 eV and 464.8 eV, due to Ti 2p(3/2) and Ti 2p(1/2), respectively. The Pd-3d peak was split into Pd-3d(5/2) and Pd-3d(3/2)peaks, and shows two bands at 334.7 and 339.9 eV for Pd-3d3 and Pd-3d5, respectively. Also, the peaks of Ag-3d have been investigated. The chemical states consisted of the O-1s, P-2p, and Ti-2p were identified in the forms of PO42- and PO43-. Based on the results of the chemical states, the chemical elements into the TiO2 oxide multilayer were also inferred to be penetrated from the electrolyte during anodic process.The structure characterization of the modified surface were performed by using FE-SEM, and from the result of biological evaluation in simulated body fluid(SBF), the biocompatibility of TiO2 oxide multilayer was effective for bioactive property.

• Journal of Korean Ophthalmic Optics Society
• /
• v.4 no.1
• /
• pp.21-25
• /
• 1999

The TiN, thin films were prepared on glass substrate by RF(radio-frequency) magnetron sputtering apparatus from a Ti target in a gaseous mixture of argon and nitrogen. In deposition, a RF power supply was used as a power source with a constant power of 240W, and the substrate was heated to $200^{\circ}C$. The films were obtained at nitogen flow rates in the range 3-9 sccm with a constant argon flow rate of 20 secm. For the films obtained, the sheet resistance and the chemical binding energy of the films was observed by four-point-probe method and x-ray photoelectron spectroscopy(XPS) depth profiling respectively. In addition, we investigated the relationship between the surface resistance and the chemical nature of the films.

• Journal of the Korean Magnetic Resonance Society
• /
• v.14 no.1
• /
• pp.28-37
• /
• 2010

Metabolites of urine samples from 6 colorectal cancer patients were analyzed by two-dimensional NMR spectroscopy, where the samples were collected before and after the surgical treatments per patient. NMR data were analyzed with the help of the metabolome database and the statistics software. Urine samples before and after the treatments showed significantly different metabolic profiles from each other. We were able to compare 10 different metabolites. Most of the assigned metabolites of every patient showed a tendency of increase after the surgery except for a few cases. The amount of changes in individual metabolites varied significantly from patient to patient, but the combination of such changes could be used to distinguish the condition before the surgery from after, which could be done by PCA analysis. The analysis via $^{1}H-^{13}C$ HSQC spectra proved to be applicable in assessing and classifying global metabolic profiles of the urines from colorectal cancer patients.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.3
• /
• pp.765-769
• /
• 2014

An analytical methodology was developed for qualitative and quantitative impurity profiling of the coloring agent Sudan III by high-performance liquid chromatography (HPLC)-diode array detection (DAD). The impurities in commercial Sudan III were characterized by comparison of their retention times and UV spectra with those of authentic standards. Four impurities regulated by International Committees in Sudan III were quantified by HPLC-selective UV detection. The impurities in Sudan dye were successfully separated on a reversed phase C18-column within 25 min and sensitively detected by UV spectrometry at two selective wavelengths. Method validation was conducted to determine linearity, precision, accuracy, and limit of quantification (LOQ). The linear dynamic range extended from 0.002 to 4.0%, with a correlation coefficient (R2) greater than 0.995. The LOQs of the impurities ranged from 8.04 to $54.29{\mu}g/mg$. Based on the established method, the levels of regulated impurities in five commercial Sudan III dyes were determined.

• Journal of the Korean Chemical Society
• /
• v.34 no.4
• /
• pp.352-359
• /
• 1990

An effecient gas chromatographic method is described to be used routinely for the rapid profiling and identification of biochemically important organic acids. It involves the solid-phase extraction of organic acids from aqueous samples using Chromosorb P as the solid sorbent and diethyl ether as the eluting solvent, with subsequent triethylamine treatment. The resulting triethylammonium salts of acids were directly converted to volatile tert-butyldimethylsiyl derivatives, which were simultaneously analyzed by two capillary columns of different polarity, DB-5 and DB-1701, under the identical temperature programming condition. The retention index (RI) and area ratio (AR) values of each peak measured on DB-5 and DB-1701 enabled rapid identification of acids by computer RI library search and AR comparison. The application of the present method to the organic acid profiling of various complex samples is demonstrated.

• Journal of the Korean Vacuum Society
• /
• v.8 no.3B
• /
• pp.283-289
• /
• 1999

Multilayer thin film reference materials for the sputter depth profiling analysis are used to calibrate the sputter depth scale by measuring the sputtering rate and to optimize the sputtering conditions for the best depth resolution. Surface analysis group of Korea Research Institute of Standards and science (KRISS) have developed various types of multilayer thin films by using an ion beam sputter deposition and in-situ surface analysis system. The chemical states of the thin films reference materials were certified by in-situ XPS and the thicknesses were certified by transmission electron microscopy (TEM).

• Journal of Korean Ophthalmic Optics Society
• /
• v.6 no.2
• /
• pp.31-35
• /
• 2001

The anti-reflective anti-static(ARAS) optical film Was designed using conducting layer $TiN_x$ by Essential Macleod program. From this results, [air ${TiN_x{\mid}SiO_2{\mid}$ glass] two layer shows wide-band AR coating in the wavelength range of 450~700 nm. The $TiN_x$ thin films were prepared on the glass substrate by RF(radio-freqency) magnetron sputtering apparatus from a Ti target in agaseous mixture of argon and nitrogen with the thickness of 7~10 nm. For the films obtained, the chemical binding energy of the films was investigated by x-ray photoelectron spectroscopy(XPS) in order to analyze the chemical nature and composition of the films. In addition, we investigated the relationship between the surface resistance and the chemical nature the sheet resistance and XPS depth profiling the chemical binding of the films.

• Proceedings of the Korea Environmental Mutagen Society Conference
• /
• 2003.05a
• /
• pp.36-37
• /
• 2003

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2003.05a
• /
• pp.36-37
• /
• 2003

The potential application of toxicogenomics to predictive toxicology has been discussed widely, but the utility of the approach remains largely unproven. Using cDNA microarrays, we have compared the gene expression profiles produced in mouse lymphoma cells by three genotoxic compounds, hydroxyurea (a carcino- gen), p-anisidine (a noncarcinogen) and paclitaxel (carcinogenicity unknown). (omitted)