• Mass Spectrometry Letters
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• v.4 no.3
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• pp.47-50
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• 2013

An ultra-fast generic LC-MS/MS method was developed for high-throughput quantification of discovery pharmacokinetic (PK) samples and its reliability was verified. The method involves a simple protein precipitation for sample preparation and the analysis by ultra-fast generic LC-MS/MS with the ballistic gradient program and selected reaction monitoring (SRM) mode. Approximately 290 new chemical entities (NCEs) (over 10,000 samples) from 5 therapeutic programs were analyzed. The calibration curves showed good linearity in the concentration range of 1, 2 or 5 to 2000 ng/mL. No significant ion suppression was observed in the elution region of all the NCEs. When approximately 300 plasma samples were continuously analyzed, the peak area of internal standard was constant and reproducible. In the repeated analysis of samples, the plasma concentrations and the area under the curve (AUC) were consistent with the results from the first analysis. These results showed that the present ultra-fast generic LC-MS/MS method is reliable in terms of selectivity, sensitivity, and reproducibility and could be useful for high-throughput quantification and other bioanalysis in drug discovery.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.7-7
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• 2011

Quantum beam technology has been expected to develop breakthroughs for nanotechnology during the third basic plan of science and technology (2006~2010). Recently, Green- or Life Innovations has taken over the national interests in the fourth basic science and technology plan (2011~2015). The NIMS (National Institute for Materials Science) has been conducting the corresponding mid-term research plans, as well as other national projects, such as nano-Green project (Global Research for Environment and Energy based on Nanomaterials science). In this lecture, the research trends in Japan and NIMS are firstly reviewed, and the typical achievements are highlighted over key nanotechnology fields. As one of the key nanotechnologies, the quantum beam research in NIMS focused on synchrotron radiation, neutron beams and ion/atom beams, having complementary attributes. The facilities used are SPring-8, nuclear reactor JRR-3, pulsed neutron source J-PARC and ion-laser-combined beams as well as excited atomic beams. Materials studied are typically fuel cell materials, superconducting/magnetic/multi-ferroic materials, quasicrystals, thermoelectric materials, precipitation-hardened steels, nanoparticle-dispersed materials. Here, we introduce a few topics of neutron scattering and ion beam nanofabrication. For neutron powder diffraction, the NIMS has developed multi-purpose pattern fitting software, post RIETAN2000. An ionic conductor, doped Pr2NiO4, which is a candidate for fuel-cell material, was analyzed by neutron powder diffraction with the software developed. The nuclear-density distribution derived revealed the two-dimensional network of the diffusion paths of oxygen ions at high temperatures. Using the high sensitivity of neutron beams for light elements, hydrogen states in a precipitation-strengthened steel were successfully evaluated. The small-angle neutron scattering (SANS) demonstrated the sensitive detection of hydrogen atoms trapped at the interfaces of nano-sized NbC. This result provides evidence for hydrogen embrittlement due to trapped hydrogen at precipitates. The ion beam technology can give novel functionality on a nano-scale and is targeting applications in plasmonics, ultra-fast optical communications, high-density recording and bio-patterning. The technologies developed are an ion-and-laser combined irradiation method for spatial control of nanoparticles, and a nano-masked ion irradiation method for patterning. Furthermore, we succeeded in implanting a wide-area nanopattern using nano-masks of anodic porous alumina. The patterning of ion implantation will be further applied for controlling protein adhesivity of biopolymers. It has thus been demonstrated that the quantum beam-based nanotechnology will lead the innovations both for nano-characterization and nano-fabrication.

• Korean Journal of Materials Research
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• v.14 no.3
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• pp.229-234
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• 2004

All the applications of natural zeolites make use of one or more of their physical and chemical properties: adsorption, ion-exchange and related molecular sieve properties, dehydration and rehydration, and siliceous composition. Accordingly, the applications of zeolite have been carried out in the various aspects because of its large cation exchange capacity and adsorption properties. In this paper, the adsorption effect of heavy metal ions in wastewater on zeolite mineral by batch adsorption process is studied. The amounts of adsorbed ions were variable by original pH and ionic concentration, especially original pH of solution had an important effect on the adsorption. In case of low pH solution, e.g. below 3.0, clinoptilolite adsorbed $Pb^{2+}$ ,$ Cd ^{2+ }$ , $Cu^{2+}$ and $Zn^{ 2+}$ , but mordenite almost did not adsorb except $Pb^{2+}$ . Under the same conditions, these ions were more adsorbed on clinoptilolite than on mordenite mineral. The velocity of adsorption was relatively fast and it was confirmed by shaking test that the equilibrium of adsorption could be attained in about one hour. The species of exchangeable cation of zeolite had an effect on its removing ability and zeolite of the sodium-exchanged type was the best.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.482-486
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• 2009

The aim of this study was to optimize a simple, fast, and economical analysis procedure for the determination of 16 different pesticides in raw milk via GC/MSD. Analyses were performed via gas chromatography with electron impact mass spectrometric detection in the selected ion monitoring mode (GC/MSD-SIM) using Pentachloronitrobenzene as the internal standard. The modified sample preparation methodology was based on the Pesticide Analytical Manual (PAM) of the FDA concerning fat extraction, ACN-ether partitioning, and clean-up of the Sep-Pak florisil cartridge. The modified methodology for the determination of the 16 pesticides was validated. The range of LOQs of the 16 pesticides was likely three times lower than their Maximum Residence Levels (MRLs). The recoveries of most of the pesticides were acceptable at the fortification levels of 0.5 and 1.0 ${\mu}g/mL$ and their RSD (%) level was less than 20%. None of the 16 pesticides were detected in the selected raw milk samples.

• Journal of Electrochemical Science and Technology
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• v.5 no.4
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• pp.109-114
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• 2014

The $Li_3V_2(PO_4)_3$/graphene nano-particles composite was successfully synthesized by a facile sol-gel method. The addition of a graphene in $Li_3V_2(PO_4)_3(LVP)$(LVP) showed the high crystallinity and influenced the morphology of the $Li_3V_2(PO_4)_3$ particles observed in X-ray diffraction (XRD) and scanning electron microscopy (SEM). The LVP/graphene samples were well connected, resulting in fast charge transfer. The effect of the addition graphene nano-particles on electrochemical performance of the materials was investigated. Compared with the pristine LVP, the LVP/graphene composite delivered a higher discharge capacity of $122mAh\;g^{-1}$ at 0.1 C-rate, better rate capability and cyclability in the potential range of 3.0-4.3 V. The electrochemical impedance spectra (EIS) measurement showed the improved electronic conductivity for the LVP/graphene composite, which can ensure the high specific capacity and rate capability.

• Rapid Communication in Photoscience
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• v.2 no.2
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• pp.60-63
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• 2013

Rhodopsins belong to a family of membrane-embedded photoactive retinylidene proteins. One opsin gene was isolated from ${\beta}$-proteobacterium (IMCC9480) which had been collected at the North Pole. It is very similar to Xanthorhodopin (XR) of HTCC2181. In this study, we carried out basic characterization of the rhodopsin. It has ${\lambda}max$ of 536, 554, and 546 nm at pH 4.0, 7.0, and 10.0, respectively. Since the pKa of its proton acceptor is around 6.27, we measured its proton pumping activity and photocycling rate at pH 8.0. It has a typical proton acceptor (D99) and donor (E110) which mediate proton translocation from intracellular to extracellular region when deduced from the sequence alignments. On the basis of in vitro proton pumping activity, it was proposed to have fast photocycling rate with M and O intermediates, indicating that it is a typical ion-pumping rhodopsin. Since the XR has not yet been expressed in any other heterologous expression system, we tried to get much more information about the XR through the XR-homologue rhodopsin.

• Journal of the Korean Vacuum Society
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• v.11 no.2
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• pp.108-112
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• 2002

We investigated the secondary electron emission characteristics of MgO layer used as the protecting material in a.c. plasma display panel(a.c.-PDPs) using a pulsed ion beam technique, where the surface charging can be effectively suppressed during the measurement. The measurement of the secondary electron emission coefficients ($\gamma$) on the surface of $SiO_2$ was carried out and then, it was found that the yields were dependent on incident ion energies. In addition, it was clearly demonstrated that the sputtering on MgO surface leads to lower yields, which suggests that the surface plays a key role on the operating conditions, such as life time, fast response, and etc.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.587-587
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• 2012

Supercapacitors, which can deliver significant energy with high power density, have attracted a lot of attention due to their potential application in energy storage. Among various oxide materials, sodium vanadate has been recognized as one of the most promising electrode materials because of high electrical conductivity. In addition, larger layer spacing of ${\beta}$-Na0.33V2O5 compared to V2O5 makes easier Li+ insertion. Moreover, ${\beta}$-Na0.33V2O5 has a tunnel like structure along b axis with 3 kinds of V site allowing it to enhance the ion intercalation by introducing three different intercalation sites along the tunnel. The tunnel can act as a fast diffusion path for ion diffusion, which can improve the overall charge storage kinetics. In this study, high quality single crystalline sodium vanadate (${\beta}$-Na0.33V2O5) nanowires were grown directly on Pt coated $SiO_2$ substrate by a facile chemical solution deposition method without employing catalyst, surfactant or carrier gas. The results show that great enhancement in capacitance was observed compared with previous reports.

• Mass Spectrometry Letters
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• v.10 no.4
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• pp.103-107
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• 2019

Low-temperature plasma (LTP) ionization is one of the ambient ionization methods typically used in mass spectrometry (MS) for fast screening of chemicals with minimal or no sample preparation. In spite of various advantages of LTP ionization method, including simple instrumentation and in-situ analysis, more general applications of the method are limited due to poor desorption of analytes with low volatilities and low ionization efficiencies in the negative ion mode. In order to overcome these limitations, an ultrasonic vibrator of a commercial hand-held humidifier was interfaced with an LTP ionization source, which generated microdroplets from sample solutions and assisted with LTP ionization. Ionization behaviors of various chemicals in microdroplet-assisted LTP (MA LTP) were tested and compared with typical LTP ionization from dried samples applied on a surface. MA LTP efficiently ionized small organic, amino, and fatty acids with low volatilities and high polarities, which were hardly ionized using the standard LTP method. Facile interaction of LTP with ultrafine droplets generated by ultrasonic resonator allows efficient ionization of relatively non-volatile and polar analytes both in the positive and negative ion modes.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.601-604
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• 2014

Two classes of morpholino-substitued thioacetate have been successfully synthesized and their electrochemical properties of self-assembled monolayers (SAMs) on Au electrode are measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The barrier property of the SAMs-modified surfaces is evaluated by using potassium ferro/ferri cyanide. The results suggest that the arenethioacetate forms higher-quality close-packed blocking monolayers in comparison with alkanethioacetate. Furthermore, it has shown that the barrier properties of these monolayers can be significantly improved by mixed SAMs formation with decanethiol. From our experimental results we find that the electron transfer reaction of $[Fe(CN)_6]^{3/4-}$ redox couple occurs predominantly through the pinholes and defects present in the SAM and both SAMs show a good and fast capacity in recognition for $Ag^+$. The morphological and elementary composition have also been examined by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS).