• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3113-3116
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• 2011

• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.370-376
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• 2013

A back propagation artificial neural network model with one hidden layer is established to correlate the liquid-liquid equilibrium data of hydrocarbon-water systems. The model has four inputs and two outputs. The network is systematically trained with 48 data points in the range of 283.15 to 405.37K. Statistical analyses show that the optimised neural network model can yield excellent agreement with experimental data(the average absolute deviations equal to 0.037% and 0.0012% for the correlated mole fractions of hydrocarbon in two coexisting liquid phases respectively). The comparison in terms of average absolute deviation between the correlated mole fractions for each binary system and literature results indicates that the artificial neural network model gives far better results. This study also shows that artificial neural network model could be developed for the phase equilibria for a family of hydrocarbon-water binaries.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.137-144
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• 1994

Spherical multicellular aggregates of adult rat hepatocytes (spheroid) which have tissue like structure, were formed and immobilized in the pores of polyurethane foam (PUF) which was used as a culture substratum. These hepatocyte/spheroids, about 100 $\mu\textrm{m}$ in diameter, have maintained higher differentiated functions than those of hepatocyte/monolayer for about 3 weeks in serum-free medium. Then, we designed a prototype module of an artificial liver support system using a PUF/spheroid packed-bed, in which hepatocyte/spheroids were immobilized at high density. The urea synthesis activity of the artificial liver was maintained at least 10 days in 100% rat blood plasma. We start examining the performance of hybrid artificial liver in an ex vivo extracorporeal experiment with an acute hepatic failure rat.

• Computers and Concrete
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• v.8 no.6
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• pp.617-629
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• 2011

In this investigation, reservoir sediment and municipal sewage sludge were sintered to form the artificial lightweight aggregates. The sintered aggregates were compared with the commercialized lightweight aggregates to in terms of potential alkali-silica reactivity and chemical stability based on analyses of their physical and chemical properties, leaching of heavy metal, alkali-silica reactivity, crystal phase species and microstructure. Experimental results demonstrated that the degree of sintering of an aggregate affected the chemical resistance more strongly than did its chemical composition. According to ASTM C289-94, all potential alkali-silica reactivity of artificial lightweight aggregates were in the harmless zone, while the potential reactivity of artificial lightweight aggregates made from reservoir sediment and municipal sewage sludge were much lower than those of traditional lightweight aggregates.

• Membrane Journal
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• v.33 no.2
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• pp.61-69
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• 2023

The technical importance of membrane-based artificial lung technology has been re-emphasized after the recent breakout of COVID-19 to treat acute lung-failure patients. The world population, particularly in Korea, is aging at an unprecedented rate, which can increase the demand for better artificial organs (AO) in the near future. Membrane technology plays a key role in artificial organ markets. Among them, membrane-based artificial lung (AL) technology has improved significantly in the past 50 years, but the survival rate of lung-failure patients is still very low. Most AL works focus on the clinical application of the AL device, not on the development of the AL membrane itself. This review summarizes the challenges and recent progress of membrane-based AL technology.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2104-2111
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• 2017

A new series comprising phenylacetyl-homoserine lactones (HSLs), caffeoyl-HSL and feruloyl-HSL, was biologically synthesized using an artificial de novo biosynthetic pathway. We developed an Escherichia coli system containing artificial biosynthetic pathways that yield phenylacetyl-HSLs from simple carbon sources. These artificial biosynthetic pathways contained the LuxI-type synthase gene (rpaI) in addition to caffeoyl-CoA and feruloyl-CoA biosynthetic genes, respectively. Finally, the yields for caffeoyl-HSL and feruloyl-HSL were $97.1{\pm}10.3$ and $65.2{\pm}5.7mg/l$, respectively, by tyrosine-overproducing E. coli with a $\text\tiny{L}$-methionine feeding strategy. In a quorum sensing (QS) competition assay, feruloyl-HSL and p-coumaroyl-HSL antagonized the QS receptor TraR in Agrobacterium tumefaciens NT1, whereas caffeoyl-HSL did not.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.614-618
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• 2014

Resveratrol, which is a polyphenolic antioxidant, is dose-dependent when used to provide health benefits, to enhance stress resistance, and to extend lifespans. However, even though resveratrol has therapeutic benefits, its clinical therapeutic effect is limited owing to its low oral bioavailability. An Escherichia coli system was developed that contains an artificial biosynthetic pathway that produces resveratrol glucoside derivatives, such as resveratrol-3-Oglucoside (piceid) and resveratrol-4'-O-glucoside (resveratroloside), from simple carbon sources. This artificial biosynthetic pathway contains a glycosyltransferase addition (YjiC from Bacillus) with resveratrol biosynthetic genes. The produced glucoside compounds were verified through the presence of a product peak(s) and also through LC/MS analyses. The strategy used in this research demonstrates the first harnessing of E. coli for de novo synthesis of resveratrol glucoside derivatives from a simple sugar medium.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1917-1923
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• 2004

Although the proteolytic activity of the Cu(II) complex of cyclen (Cyc) is greatly enhanced upon attachment to a cross-linked polystyrene (PS), the Cu(II)Cyc-containing PS derivatives reported previously hydrolyzed only a very limited number of proteins. The PS-based artificial metalloproteases can overcome thermal, mechanical, and chemical instabilities of natural proteases, but the narrow substrate selectivity of the artificial metalloproteases limits their industrial application. In the present study, artificial metalloproteases exhibiting broad substrate selectivity were synthesized by attaching Cu(II)Cyc to a PS derivative using linkers with various structures in an attempt to facilitate the interaction of various protein substrates with the PS surface. The new artificial metalloproteases hydrolyzed all of the four protein substrates (albumin, myoglobin, ${\gamma}$-globulin, and lysozyme) examined, manifesting $k_{cat}/K_m$ values of 28-1500 $h_{-1}M_{-1}$ at 50 $^{\circ}C$. The improvement in substrate selectivity is attributed to steric and/or polar interaction between the bound protein and the PS surface as well as the hydrophobicity of the microenvironment of the catalytic centers.

• Bulletin of the Korean Chemical Society
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• v.26 no.12
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• pp.1911-1920
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• 2005

Effective artificial metalloproteases have been designed by using cross-linked polystyrene as the backbone. Artificial active sites comprising Cu(II) complexes as the catalytic site and other metal centers or organic functionalities as binding sites were synthesized. The activity of Cu(II) centers for peptide hydrolysis was greatly enhanced on attachment to polystyrene. By placing binding sites in proximity to the catalytic centers, the ability to hydrolyze a variety of protein substrates at selected cleavage sites was improved. Thus far, the most advanced immobile artificial proteases have been obtained by attaching the aldehyde group in proximity to the Cu(II) complex of cyclen.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.567-573
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• 2012

Compared with the natural marble, the artificial marble has the advantages of excellent appearance, high degree of finish, even color, fine pressure and wear resistance, bear erosion and weathering, etc. It can be widely used in kitchen countertops, bath vanity tops, table tops, furniture, reception desks, etc. However, large amounts of artificial marble waste such as scraps or dust have been generated from sawing and polishing processes in artificial marble industry. Waste from artificial marble industry is increasing according to demand magnification of luxurious interior material. Artificial marble wastes can be recycled as aluminum oxide used as raw materials in electronic materials, ceramics production, etc., and methyl methacrylate(MMA) which become a raw material of artificial marble by pulverization, pyrolysis and distillation processes. The characteristics of artificial marble wastes was analyzed by using TGA/DSC and element analysis. Crude aluminum oxide was obtained from artificial marble waste by pulverization and thermal decomposition under nitrogen atmosphere. In this work, Box-Behnken design was used to optimize the pyrolysis process. The characteristics of crude aluminum oxide was evaluated by chromaticity analysis, element analysis, and surface area.