• Journal of Plant Biology
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• v.24 no.1
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• pp.13-19
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• 1981

In order to investigate the effects of ammonium citrate and ammonium succinate on the growth and absorption of nitrogen compounds supplied in the medium, Korean ginseng (Panax ginseng C. A. Meyer) calli were suspension cultured in MS medium with various concentrations of ammonium citrate and ammonium succinate. When Korean ginseng calli were cultured with 10 mM ammonium citrate, 10 mM ammonium succinate, and 10 mM ammonium nitrate (control) in MS media as the nitrogen sources, the growth, $NO_3$-N absorption and total nitrogen content of the Korean ginseng cells were greatest in the ammonium citrate and ammonium succinate concentrations. When Korean ginseng calli were cultured with 5 mM ammonium citrate and 5 mM ammonium succinate, the growth and nitrogen content were superior to those of the control: however, $NO_3$-N and $NH_4$-N absorptions were similar to those of the control. In conclusion, the 10 mM ammonium citrate and 10 mM ammonium succinate may be better able to facilitate the growth and $NO_3$

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.53-63
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• 2009

This work proposes a 10b 100MS/s 27.2mW $0.8mm^2$ 0.18um CMOS ADC for WLAN such as an IEEE 802.11n standard. The proposed ADC employs a three-stage pipeline architecture and minimizes power consumption and chip area by sharing as many circuits as possible. Two multiplying DACs share a single amplifier without MOS switches connected in series while the shared amplifier does not show a conventional memory effect. All three flash ADCs use only one resistor ladder while the second and third flash ADCs share all pre-amps to further reduce power consumption and chip area. The interpolation circuit employed in the flash ADCs halves the required number of pre-amps and an input-output isolated dynamic latch reduces the increased kickback noise caused by the pre-amp sharing. The prototype ADC implemented in a 0.18um n-well 1P6M CMOS process shows the DNL and INL within 0.83LSB and 1.52LSB at 10b, respectively. The ADC measures an SNDR of 52.1dB and an SFDR of 67.6dB at a sampling rate of 100MS/s. The ADC with an active die area of $0.8mm^2$ consumes 27.2mW at 1.8V and 100MS/s.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.154-159
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• 2004

In this study, in order to perform more efficiently reliability design and integrity assessment of structural members, the relational database management program on the engineering plastics was constructed. This program contained 476 grades for 14 kinds of the engineering plastics and was developed using MS-access and MS-visualbasic. This program consists of 3 modules; search condition, probabilistic characteristics of material property, evaluation of P-S-N curve. We perform fatigue test for probabilistic durability analysis and this results input the database program to estimate P-S-N.

• Journal of Life Science
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• v.26 no.10
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• pp.1196-1201
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• 2016

The ovary parts of Nelumbo nucifera were extracted in 80% methanol (MeOH), and the concentrated extract was then partitioned using n-hexane, ethyl acetate (EtOAc), n-butanol (n-BuOH), and H₂O, successively. Using an octadecyl silica gel (ODS) column, silica gel (SiO₂) column chromatography, and a HPLC purification system, five compounds were isolated from the n-hexane fraction obtained from the extract of N. nucifera ovary. The chemical structures of the metabolites were determined using several spectroscopic methods, including NMR and GC/MS and MS of 1-eicosanol (1), cycloartenol (2), trans-squalene (3), pentadecanoic acid (4), and β-sitosterol (5). This study is a first attempt to isolate and identify secondary metabolites from the ovary of N. nucifera. The results indicated that the extract of N. nucifera ovary has biological effects, such as antibacterial and -tumor activity. Therefore, it could decrease the risk of HIV transmission through breastfeeding.

• Mass Spectrometry Letters
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• v.6 no.2
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• pp.31-37
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• 2015

Phosphorylation upon protein is well known to a key regulator that implicates in modulating many cellular processes like growth, migration, and differentiation. Up to date, grafting of multidimensional separation techniques onto advanced mass spectrometry (MS) has emerged as a promising tool for figuring out the biological functions of phosphorylation in a cell. However, advanced MS-based phosphoproteomics is still challenging, due to its intrinsic issues, i.e., low stoichiometry, less susceptibility in positive ion mode, and low abundance in biological sample. To overcome these bottlenecks, diverse techniques (e.g., SCX, HILIC, ERLIC, IMAC, TiO₂, etc.) are continuously developed for on-/off-line enrichment of phosphorylated protein (or peptide) from biological samples, thereby helping qualitative/quantitative determination of phosphorylated protein and its phosphorylated sites. In this review, we introduce to the overall views of enrichment tools that are universally used to selectively isolate targeted phosphorylated protein (or peptide) from ordinary ones before MS-based phospoproteomic analysis.

• Journal of Korean Neurosurgical Society
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• v.42 no.6
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• pp.470-474
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• 2007

Objective : The brain is dependent on glucose as an energy source. Intricate homeostatic mechanisms have been implicated in maintaining the blood glucose concentration in the brain. The aim of this study is to find the way to identify the metabolic proteins regulating the glucose in rat hypothalamus. Methods : In this study, we analysed the secretome from rat hypothalamus in vivo. We introduced 500 nM of insulin into the rat hypothalamus. The chromatographic patterns of the secretome were identified, after which Mass Spectrometry-Mass Spectrometry (MS-MS) analysis was performed. Results : In Liquid Chromatography-Mass Spectrometry (LC-MS) analysis, 60 proteins were identified in the secretome. Among them, 8 novel proteins were unveiled and were associated with the energy metabolism of insulin signaling in mitochondria of rat hypothalamic neuron. Nineteen other proteins have unknown functions. These ligands were confirmed to be secreting from the rat hypothalmus on insulin signaling by western blotting. Conclusion : The hypothalamus is the master endocrine gland responsible for the regulation of various physiological and metabolic processes. Proteomics using LC-MS analysis offer a efficient means for generating a comprehensive analysis of hypothalamic protein expression by insulin signaling.

• Mass Spectrometry Letters
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• v.14 no.4
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• pp.173-177
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• 2023

Kendrick plots offer an alternative visualization of mass spectral data which reveals ion series and patterning by turning a mass spectrum into a map, plotting the fractional mass (wrongly called mass defect) as a function of mass-to-charge ratios and ion abundances. Although routinely used for polymer mass spectrometry, two unreported applications of these Kendrick plots are proposed using the program "kendo2": the graphical recalibration of a mass spectrum via the simulation of a theoretical fractional mass and a multi-segment fit; and the rapid evaluation of scan-to-scan variation of accurate mass measurements used as tolerances for the blank subtraction of UPLC-MS data files. Both applications are compatible with any type of high-resolution MS data including LC/GC-MS(/MS).

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.397-403
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• 2018

The leaves of Spiraea prunifolia were extracted with 80% aqueous MeOH and the concentrates were partitioned into EtOAc, n-BuOH, and $H_2O$ fractions. The repeated $SiO_2$ or ODS column, and medium pressure liquid chromatographies for the n-BuOH fraction led to isolation of two phenolic glucosides. The chemical structures of these compounds were determined as isosalicin (1) and crenatin (2) based on spectroscopic analyses including Nuclear magnetic resonance and MS. Extracts were analyzed using UPLC-MS/MS providing a short analysis time within 5 min using MRM technique. The concentration of crenatin was higher as 9.53 mg/g and isosalicin was lower as 0.65 mg/g. Neuroprotective effects of these compounds against hydrogen peroxide ($H_2O_2$)-induced neurotoxicity were evaluated. The results showed that exposure to $H_2O_2$ induced morphological changes, cell death and neurotoxicity in SK-N-MC cells. However, pretreatment with crenatin resulted in inhibition of morphological change, reduction of loss of cell viability and attenuation of neuronal damage. These results suggested that neuroprotective effect of crenatin isolated from S. prunifolia can be a good candidate for the development of health beneficial foods which can ameliorate the degenerative neuronal disease caused by oxidative stress.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.2
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• pp.39-47
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• 2017

Purpose: A sensitive gas chromatography mass spectrometry (GC-MS) method was developed for screening of fatty acid oxidation disorders. Methods: The assay utilized a simple protein precipitation with sulfosalicylic acid followed by tert-butyl dimethylsilyl (TBDMS) derivatization of hydroxyl functional group by N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA). Results: Calibration curves of spiked pooled plasma showed a linear relationship in the range of 0.01 ng -2 mg with correlation coefficient value greater than 0.98. Limits of detection (LOD) and limits of quantification (LOQ) were found in the range of 0.9-8.8 ng and 9-88 ng, respectively. Conclusion: The new developed method might be useful for a rapid, sensitive screening of inherited fatty acid oxidation disorders. In addition, the method expected to be one of the alternative method for screening newborns of metabolic disorders in the laboratories where expensive MS/MS is unavailable.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.5
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• pp.352-355
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• 2002

Mature embryos of five oat genotypes were cultured to develop an efficient method of callus induction and plant regeneration. Murashige and Skoog(MS) and N6 media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin were used for callus induction. Percentage of callus induction showed significant among the combinations of plant growth regulators. Callus induction showed high efficiency in medium containing 3 mg/$\ell$ of 2,4-D. The high frequency of callus induction was obtained in Gwiri37. For plant regeneration, calli induced from mature embryos were transferred onto MS and N6 media supplemented with combinations of 6-benzyladenine (BA) and naphthaleneacetic acid (NAA) for 5 weeks. Percentage of plant regeneration showed high in MS medium containing 0.2 mg/$\ell$ of NAA and 1 mg/$\ell$ of BA. The callus initiation medium affected the subsequent plant regeneration. Treatment with 3 mg/$\ell$ of 2,4-D, and 3 mg/$\ell$ of 2,4-D and 3 mg/$\ell$ of kinetin in callus induction media showed high frequency for plant regeneration. Plant regeneration frequency among the genotypes showed significant. Especially, Gwiri37 showed high regeneration frequency. Regenerated shoots were treated with 200, 350 and 500 mg/$\ell$ of indole-3-butyric acid (IBA) transferred onto half-strength MS medium without plant growth regulators. Treatment of shoots with IBA induced root formation rapidly.