• KSBB Journal
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• v.21 no.6 s.101
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• pp.405-409
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• 2006

Bokbunja (Rubus coreanus Miquel) is a wild berry belonging to Rosaceae genus of which application areas have been expanded due to many health effects. Bokbunja berry contains carbohydrates, protein, fats and dietary fibers as major components and various flavonoids such as tannins, volatile components including organic acids, alcohols and hydrocarbons as minor ones. Those active compounds attribute to the following health effects: increase in immune function and antioxidant activity, rise in hormone secretion, suppression of the growth of type B hepatitis virus, and control of weight gain. To utilize the above activities, many products have been developed by using Bokbunja berry extracts in the area of foods, liquors, and cosmetics. Recently, pure compounds have been isolated from the extracts for the development of medicines. In this mini review, the state-of-the-art of Bokbunja researches and applications including papers and patents is summarized.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.5
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• pp.373-381
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• 2017

$RuO_2$ is a common active component of Dimensionally Stable Anodes (DSAs) for chlorine evolution that can be used in wastewater treatment systems. The recent improvement of chlorine evolution using nanostructures of $RuO_2$ electrodes to increase the treatment efficiency and reduce the energy consumption of this process has received much attention. In this study, $RuO_2$ nanorod and nanosheet electrodes were simply fabricated using the sol-gel method with organic surfactants as the templates. The obtained $RuO_2$ nanorod and nanosheet electrodes exhibit enhanced electrocatalytic activities for chlorine evolution possibly due to the active surface areas, especially the outer active surface areas, which are attributed to the increase in mass transfers compared with a conventional nanograin electrode. The electrocatalytic activities for chlorine evolution were increased up to 20 % in the case of the nanorod electrode and 35% in the case of the nanosheet electrode compared with the nanograin electrode. The $RuO_2$ nanorod 80 nm in length and 20-30 nm in width and the $RuO_2$ nanosheet 40-60 nm in length and 40 nm in width are formed on the surface of Ti substrates. These results support that the templated $RuO_2$ nanorod and nanosheet electrodes are promising anode materials for chlorine evolution in future applications.

• Applied Chemistry for Engineering
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• v.27 no.6
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• pp.555-564
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• 2016

In recent years, methanol has attracted much attention since it can be cleanly manufactured by the combined use of atmospheric $CO_2$ recycling and water splitting via renewable energy. For the concept of "methanol economy", an active methanol synthesis catalyst should be prepared in a sophisticated manner rather than by empirical optimization approach. Even though Cu/ZnO-based catalysts prepared by coprecipitation are well known and have been extensively investigated even for a century, fundamental understanding on the precipitation chemistry and catalyst nanostructure has recently been achieved due to complexity of the necessary preparation steps such as precipitation, ageing, filtering, washing, drying, calcination and reduction. Herein we review the recent reports regarding the effects of various synthesis variables in each step on the physicochemical properties of materials in precursor, calcined and reduced states. The relationship between these characteristics and the catalytic performance will also be discussed because many variables in each step strongly influence the final catalytic activity, called "chemical memory". All discussion focuses on how to prepare a highly active Cu/ZnO-based catalyst for methanol synthesis. Furthermore, the preparation strategy we deliver here would be utilized for designing other coprecipitation-derived supported metal or metal oxide catalysts.

• KSBB Journal
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• v.21 no.2
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• pp.118-122
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• 2006

In this report, we describe that the use of GroEL/GroES-enriched S30 extract remarkably enhances the solubility and enzymatic activity of cell-free synthesized rPA, which requires the correct formation of 9 disulfide bonds for its biological activity. We found that the stable maintenance of redox potential is necessary, but not sufficient for the optimal expression of active rPA. In a control reaction without using additional molecular chaperones, most of the rPA molecules were aggregated almost instantly after their expression and thus failed to exhibit the enzymatic activity. However, by the use of GroEL/GroES-enriched extract, combined with IAM-treatment, approximately $30{\mu}g/ml$ of active rPA was expressed in the cell-free synthesis reaction. This result not only demonstrates the efficient production of complex proteins, but also shows the control and flexibility offered by the cell-free protein synthesis system.

• Korean Journal of Chemical Engineering
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• v.35 no.12
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• pp.2442-2451
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• 2018

Novel highly active visible-light photocatalysts in the form of zinc bismuth oxide ($ZnBi_2O_4$) and graphite hybrid composites were prepared by coupling via a co-precipitation method followed by calcination at $450^{\circ}C$. The asprepared $ZnBi_2O_4$-graphite hybrid composites were tested for the degradation of rhodamine B (RhB) solutions under visible-light irradiation. The existence of strong electronic coupling between the two components within the $ZnBi_2O_4$-graphite heterostructure suppressed the photogenerated recombination of electrons and holes to a remarkable extent. The prepared composite exhibited excellent photocatalytic activity, leading to more than 93% of RhB degradation at an initial concentration of $50mg{\cdot}L^{-1}$ with 1.0 g catalyst per liter in 150 min. The excellent visible-light photocatalytic mineralization of $ZnBi_2O_4-1.0graphite$ in comparison with pristine $ZnBi_2O_4$ could be attributed to synergetic effects, charge transfer between $ZnBi_2O_4$ and graphite, and the separation efficiency of the photogenerated electrons and holes. The photo-induced $h^+$ and the superoxide anion were the major active species responsible for the photodegradation process. The results demonstrate the feasibility of $ZnBi_2O_4-1.0graphite$ as a potential heterogeneous photocatalyst for environmental remediation.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1117-1124
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• 2011

We present a brief review for theoretical/computational studies of proton transfer processes of some simple biomolecules promoted by microsolvating water molecules. Focus is given on the relative stability of the canonical vs. zwitterionic forms of amino acids, tautomeric forms of the DNA base adenine, and the biologically active vs. inactive forms of nicotine. The biochemical implications of these findings are also discussed.

• Journal of the Korean Chemical Society
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• v.55 no.6
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• pp.1000-1006
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• 2011

A systematic study of Knoevenagel reaction and Nazarov cyclization was made on variety of less reactive carbonyl compounds such as ${\beta}$-ketoesters, 1,3-diketones and cyclic active methylene compounds using $Yb(OTf)_3$ as the catalyst. Recycling study confirms reusability of the catalyst without much loss of activity.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.403-406
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• 1990

Two types of new silica catalysts modified with benzenesulfonic acid derivatives were prepared by esterification or phenylation followed by sulfonation. Both catalysts thus prepared were tested as acid catalysts for 2-propanol dehydration and cumene dealkylation reactions. B catalyst () were more active than A catalyst (). Highter catalytic activity for B catalyst may be accounted for by higher resistance to water, higher acid strength, more acidity, and better thermal stability as compared with A catalyst.

• Bulletin of the Korean Chemical Society
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• v.10 no.6
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• pp.559-563
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• 1989

Optically active (R)- and (S)-2-benzyloxy-1-butanol have been prepared by a previously described asymmetric synthesis based on a chiral oxathiane and have been converted into (R)-(+)-4-hexanolide, a component of the pheromone secreted by the female of the dermestid beetle, and its enantiomer.

• Korean Journal of Pharmacognosy
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• v.35 no.2 s.137
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• pp.134-138
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• 2004

A bioassay-guided fractionation of the whole extract of Viscum album var. coloratum Ohwi (Loranthaceae) led to the isolation of two triterpenoidal components; oleanolic acid (1) and ${\beta}-amyrin$ acetate (2), and a flavonoid, homoflavoyadorinin B (3) as well as large quantity of free fatty acid mixtures as active ingredients of the extract responsible for the antitumoral property. The EtOAc soluble fraction and BuOH soluble fraction of the extract demonstrated a significant inhibition on the proliferation of cultured human tumor cells such as A549 (non small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system), and HCT-15 (colon) in vitro, whereas the remaining water soluble fraction exhibited a poor inhibition. The intensive phytochemical investigation of the EtOAc soluble fraction and BuOH soluble fraction of the extract indicated that the oleanolic acid (1) and large amounts of free fatty acid mixtures might be attributed to the in vitro antitumoral property of the whole extract of Viscum album var. coloratum.