• YAKHAK HOEJI
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• v.57 no.4
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• pp.250-257
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• 2013

Biosimilars are important drugs in medicine and contain many glycosylated proteins. Thorough analysis of the glycosylated protein is a prerequisite for evaluation of biosimilar glycan drugs. A method to assess the diversity of N-glycosylation sites and N-glycans from biosimilar glycan drugs has been developed using two separate methods, LC-MS/MS and MALDI-TOF MS, respectively. Development of sensitive, accurate, and efficient methods for evaluation of glycoproteins is still needed. In this study, analysis of both N-glycosylation sites and N-glycans of glycoprotein was performed using the same LC-MS/MS with two different nano-LC columns, nano-C18 and nano-porous graphitized carbon (nano-PGC) columns. N-glycosylated proteins, including RNAse B (one N-glycosylation site), Fetuin (three sites), and ${\alpha}$-1 acid glycoprotein (four sites), were used, and small amounts of each protein were used for identification of N-glycosylation sites. In addition, high mannose N-glycans (one type of typical glycan structure), Mannose 5 and 9, eluted from RNAse B, were successfully identified using nano-PGC-LC MS/MS analysis, and the abundance of each glycan from the glycoprotein was calculated. This study demonstrated an accurate and efficient method for determination of N-glycosylation sites and N-glycans of glycoproteins based on high sensitive LC-MS/MS using two different nano-columns; this method could be applied for evaluation of the quality of various biosimilar drugs containing N-glycosylation groups.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.3943-3949
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• 2012

A series of aromatic hydrazides 3a-j were prepared by refluxing esters 2a-j with hydrazine hydrate in methanol, which were prepared by the esterification of 1a-j. Acetohydrazides 3a-j upon treatment with carbon disulfide and methanolic potassium hydroxide yielded potassium dithiocarbazate salts 4a-j, which on refluxing with hydrazine hydrate yielded substituted 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones 5a-j. The target compounds 6a-j were synthesized by condensing furan-3-carboxylic acid in the presence of polyphosphoric acid under reflux. The structures of newly synthesized compounds were characterized by IR, $^1H$ NMR, $^{13}C$ NMR, elemental analysis and mass spectrometric studies. All the synthesized compounds were screened for their urease, acetylcholine esterase inhibition, antioxidant and alkaline phosphatase inhibition activity. Almost all of the compounds 6a-j showed good to excellent activities against urease and acetylcholine esterase more than the reference drugs. Compounds 6f and 6g were more potent scavenger of free radicals than the reference n-propyl gallate. Compound 6b and 6h showed excellent activities of alkaline phosphatase as compare to the reference $KH_2PO_4$.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4161-4164
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• 2012

Density functional MO calculations for the methylsilole anion of $[C_4H_4SiMe]^-$ and methylgermole anion of $[C_4H_4SiMe]^-$ at the B3LYP (full)/6-311+$G^*$ level (GAUSSIAN 94) were carried out and characterized by frequency analysis. The ground state structure for the methylsilole anion and methylgermole anion is that the methyl group is pyramidalized with highly localized structure. The difference between the calculated $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are 9.4 and 11.5 pm, respectively. The E-Me vector forms an angle of $67.9^{\circ}$ and $78.2^{\circ}$ with the $C_4E$ plane, respectively. The optimized structures of the saddle point state for the methylsilole anion and methylgermole anion have been also found as a planar with highly delocalized structure. The optimized $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are nearly equal for both cases. The methyl group is located in the plane of $C_4E$ ring and the angle between the E-Me vector and the $C_4E$ plane for the methylsilole anion and methylgermole anion is $2.0^{\circ}$ and $2.3^{\circ}$, respectively. The energy difference between the ground state structure and the transition state structure is only 5.1 kcal $mol^{-1}$ for the methylsilole anion. However, the energy difference of the methylgermole anion is 14.9 kcal $mol^{-1}$, which is much higher than that for the corresponding methylsilole monoanion by 9.8 kcal $mol^{-1}$. Based on MO calculations, we suggest that the head-to-tail dimer compound, 4, result from [2+2] cycloaddition of silicon-carbon double bond character in the highly delocalized transition state of 1. However, the inversion barrier for the methylgermole anion is too high to dimerize.

• Steel and Composite Structures
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• v.18 no.3
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• pp.583-601
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• 2015

In the present study, the combined effects of thermal and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated beams are numerically analyzed. The finite element modelling of laminated composite beams and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the finite element analysis (FEA) is demonstrated by comparing the experimental test results obtained due to mechanical loadings under the influence of thermal environment with those derived using the present FEA. Various parametric studies are also performed to investigate the effect of thermal loading on interlaminar stresses generated in symmetric, anti-symmetric, asymmetric, unidirectional, cross-ply, and balanced composite laminated beams of different stacking sequences with identical mechanical loadings and various boundary conditions. It is shown that the elevated thermal environment lead to higher interlaminar shear stresses varying with the stacking sequence, length to thickness ratio, ply orientations under identical mechanical loading and boundary conditions of the composite laminated beams. It is realized that the magnitude of the interlaminar stresses along xz plane is always much higher than those of along yz plane irrespective of the ply-orientation, length to thickness ratios and boundary conditions of the composite laminated beams. It is also observed that the effect of thermal environment on the interlaminar shear stresses in carbon-epoxy fiber reinforced composite laminated beams are increasing in the order of symmetric cross-ply laminate, unidirectional laminate, asymmetric cross-ply laminate and anti-symmetric laminate. The interlaminar shear stresses are higher in thinner composite laminated beams compared to that in thicker composite laminated beams under all environmental temperatures irrespective of the laminate stacking sequence, ply-orientation and boundary conditions.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.211-217
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• 2017

In this study, we investigated to the heat transfer performance of coating nano-structure with various shapes and patterns on the heat transfer surface. As a result of the measurement of the 3D nano shape, it was confirmed that the roughness generally increases when the adhesive is sprayed on the coating surface and finished durability experiment. In the case of TEOS adhesive, the roughness increased by $0.074{\mu}m$, $0.012{\mu}m$ and $0.015{\mu}m$, and the contact angle decreased $12.64^{\circ}$, $1.31^{\circ}$, $9.84^{\circ}$ at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of PVA adhesive, the roughness increased by $0.069{\mu}m$, $0.056{\mu}m$ and $0.03{\mu}m$, and the contact angle decreased $2.85^{\circ}$, $4.82^{\circ}$, $6.96^{\circ}$ at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of DGEBF adhesive, the roughness increased by $0.042{\mu}m$, $0.053{\mu}m$ and $0{\mu}m$, and the contact angle decreased $0.81^{\circ}$ at the coating time of 120 seconds, increased $4.82^{\circ}$, $6.96^{\circ}$ at the coating time of 180 seconds and 240 seconds, respectively. As a result, the durability tends to decrease as more nano-structures are deposited, and 3D nano shapes, contact angles and SEM photographs showed that the performance of the PVA adhesive was superior among the three adhesives.

• Journal of the Korea Institute of Building Construction
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• v.17 no.3
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• pp.235-243
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• 2017

Carbonation of concrete is being occurred due to interaction of atmospheric carbon dioxide with hydroxides. Reinforce concrete (RC) structure is getting collapse or accident due to corrosion of embedded steel rebar. The maintenance of reinforced concrete structure recently has the attention of researchers regarding durability of structure and its importance day by day is increasing. In order to study the carbonation progress of pre-repaired concrete, present study was carried out to measure the carbonation velocity for different repair materials up to 100% of carbonation. The obtained results have predicted the carbonation progress of repair materials in service condition. These results have been verified by FEM and FDM analysis. As a result, the carbonation depth can be predicted by using the carbonation prediction formula after the repair, and the analytical and the experimental values are almost similar when the initial $Ca(OH)_2$ concentration is assumed to be 40%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.511-515
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• 2002

Paeoniae radix has been considered as one of the most important crude drugs used in traditional oriental medicine and has been employed as a circulatory tonic in care of weakness, night sweats, and lumbar pain, etc. Platelet activation plays an important role in thrombosis and haemostasis. Active compounds for the inhibition of platelet activation from Paeoniae radix were extracted and fractionated into five fractions. Its fraction two and three of ethyl acetate extract inhibited the aggregation of washed rabbit platelets induced by collagen. Two active compounds, bezoyloxypaeoniflorin and paeoniflorin, were isolated from fraction two and three by silica gel column and high performance liquid chromatography. The chemical structures were determined by comparison of their proton and carbon nuclear magnetic resonance spectra. Benzoyloxypaeoniflorin showed strong inhibition at the concentration of 100 ug/mL against collagen-induced washed rabbit platelets aggregation. It is suggested that Paeoniae radix has become food material to prevent a cardiovascular disease.

• Tribology and Lubricants
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• v.30 no.6
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• pp.323-329
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• 2014

The friction-reducing properties of lubricants containing ionic liquids based on ammonium dithiocarbamate are studied. The ionic liquids are produced through the following two steps: the synthesis of sodium alkyl dithiocarbamates via the substitution reaction of dialkylamine and carbon disulfide and their subsequent conversion into ammonium dithiocarbamate-based ionic liquids through an ion-exchange reaction with a quaternary alkyl ammonium halide salt. The structures of the ionic liquids are characterized by NMR spectroscopy and Fourier transform infrared spectroscopy. The isolated yields of the ionic liquids, which are viscous and pale yellow, are approximately 92%. The Brookfield viscosities and pour points of the ionic liquids are determined. Further, their wear resistances are measured through the four-ball wear test and the Schwingung Reibung Ver-schleiss (oscillation, friction, wear) test. The wear scar diameter of the lubricants containing 1 wt of the quaternary alkyl ammonium dithiocarbamate-based ionic liquids (0.475-0.631 mm) is significantly lower than that of the base oil (0.825 mm), proving that the ammonium dithiocarbamate-based ionic liquids have good friction-reducing characteristics. However, these friction-reducing characteristics fade significantly after long-term storage, owing to the degradation of the ionic liquids.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.448-448
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• 2010

Magnetic random access memory (MRAM) has made a prominent progress in memory performance and has brought a bright prospect for the next generation nonvolatile memory technologies due to its excellent advantages. Dry etching process of magnetic thin films is one of the important issues for the magnetic devices such as magnetic tunneling junctions (MTJs) based MRAM. CoFeB is a well-known soft ferromagnetic material, of particular interest for magnetic tunnel junctions (MTJs) and other devices based on tunneling magneto-resistance (TMR), such as spin-transfer-torque MRAM. One particular example is the CoFeB - MgO - CoFeB system, which has already been integrated in MRAM. In all of these applications, knowledge of control over the etching properties of CoFeB is crucial. Recently, transferring the pattern by using milling is a commonly used, although the redeposition of back-sputtered etch products on the sidewalls and the low etch rate of this method are main disadvantages. So the other method which has reported about much higher etch rates of >$50{\AA}/s$ for magnetic multi-layer structures using $Cl_2$/Ar plasmas is proposed. However, the chlorinated etch residues on the sidewalls of the etched features tend to severely corrode the magnetic material. Besides avoiding corrosion, during etching facets format the sidewalls of the mask due to physical sputtering of the mask material. Therefore, in this work, magnetic material such as CoFeB was etched in an ICP etching system using the gases which can be expected to form volatile metallo-organic compounds. As the gases, carbon monoxide (CO) and ammonia ($NH_3$) were used as etching gases to form carbonyl volatiles, and the etched features of CoFeB thin films under by Ta masking material were observed with electron microscopy to confirm etched resolution. And the etch conditions such as bias power, gas combination flow, process pressure, and source power were varied to find out and control the properties of magnetic layer during the process.

• Journal of Korean Society on Water Environment
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• v.23 no.4
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• pp.482-489
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• 2007

Fluorescence properties and carbohydrate content were investigated using ultrafiltrated size fractions of dissolved organic matters (DOM) originated from different sources. The materials included a treated sewage, an algal organic matter, and a soil leachate, all of which are major constituents of dissolved organic matter in a typical urban river. Four different size fractions were separated from the three sources of each DOM. The size distribution demonstrated that a higher molecular weight fraction was more present in soil leachate compared to two other source DOMs. A higher content of carbohydrates was observed in the following order - algal DOM > treated sewage > soil leachate. A wide range of specific UV absorbance was observed from size fractions of a single source DOM, indicating that aromatic carbon structures are heterogeneously distributed within one source of DOM. The structural heterogeneity was the most pronounced for the soil leachate. The fluorescence index ($F_{450}/F_{500}$) of the treated sewage was similar to that (2.0) typically obtained from autochthonous DOM, suggesting that the treated sewage exhibited autochthonous organic matter-like properties. No protein-like fluorescence intensities were observed for all of the soil leachate size fractions whereas they were observed with two other source DOMs. Based upon the fluorescence peak ratios from fluorescence excitation-emission matrix (EEM), two discrimination indices could be suggested to distinguish three different source DOMs. It is expected that the suggested discrimination indices will be useful to predict the sources of DOM in a typical urban river affected by treated sewage.