Sung-Suk Lee

Preparation of a Thermoplastic Lignin-Based Biomaterial through Atom Transfer Radical Polymerization

Graft copolymerization of styrene onto kraft lignin (KL) was achieved by atom transfer radical polymerization (ATRP) using a fully substituted lignin-based macroinitiator (KLM). The number average of molecular mass (Mn) of polystyrene copolymer graft side-chains was achieved by varying the ratio of the DMF: water solvent system from 5:0 to 1:4. A Mn of up to ∼206,000 was obtained using a DMF/water ratio of 3:2 (v/v). However, as the Mn increased, the overall ATRP became less controlled. In addition, the thermal properties of the lignin-g-polystyrene copolymers improved significantly with increasing Mn of polystyrene copolymer side-chains.

Degradation of endocrine disrupting chemicals by genetic transformants with two lignin degrading enzymes in Phlebia tremellosa.

A white rot fungus Phlebia tremellosa produced lignin degrading enzymes, which showed degrading activity against various recalcitrant compounds. However, manganese peroxidase (MnP) activity, one of lignin degrading enzymes, was very low in this fungus under various culture conditions. An expression vector that carried both the laccase and MnP genes was constructed using laccase genomic DNA of P. tremellosa and MnP cDNA from Polyporus brumalis. P. tremellosa was genetically transformed using the expression vector to obtain fungal transformants showing increased laccase and MnP activity. Many transformants showed highly increased laccase and MnP activity at the same time in liquid medium, and three of them were used to degrade endocrine disrupting chemicals. The transformant not only degraded bisphenol A and nonylphenol more rapidly but also removed the estrogenic activities of the chemicals faster than the wild type strain.

Elemol from Chamaecyparis obtusa ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis

Chamaecyparis obtusa has been traditionally used as an antibiotic agent and in cosmetics for the prevention of microorganism infection and skin troubles. Atopic dermatitis (AD) is a chronic inflammatory skin disease that encompasses immunologic responses, susceptibility factors and compromised skin-barrier function. Use of plant medicines in therapeutic treatment of AD has recently been suggested as an alternative therapeutic option. The present study examined the effect of elemol, an active component of Chamaecyparis obtusa, on AD using in vivo and in vitro models. RBL-2H3 cells were stimulated with concanavalin A and dinitrophenyl human serum albumin, and atopic dermatitis was induced in BALB/c mice by topical application of 2,4-dinitrochlorobenzene (DNCB) prior to elemol treatment. The mRNA expression was evaluated by reverse transcription quantitative polymerase chain reaction, and the levels of β-hexosaminidase and serum immunoglobulin E (IgE) were examined by ELISA. Histological changes were also performed by microscopy. Elemol attenuated the onset of AD-like skin lesions, reduced serum IgE levels and decreased mast cell infiltration into the dermis and hypodermis. In addition, elemol downregulated the transcriptional expression of several pro-inflammatory cytokines, including TNF-α, IL-1β, IL-6 and IκBα, in the skin of the DNCB-induced animal models of AD. In the RBL-2H3 mast cell line, elemol significantly inhibited the mRNA expression of IL-4 and IL-13, and further attenuated the release of β-hexosaminidase from mast cells. Histological examination revealed that elemol significantly ameliorated the DNCB-induced dermal destruction in mice. The results of the present study suggested that elemol may have therapeutic potential in the treatment of AD due to its immunosuppressive effects.

Cyproconazole impregnation into wood using sub- and supercritical carbon dioxide

Supercritical fluid (SCF) impregnation is a promising preservative treatment method for wood. In order to commercialize the sub- and supercritical CO2 biocide treatment, better understanding of the fluid phase and its effect on treatment results have to be demonstrated and developed. Preservative treatability under super- and subcritical fluid conditions was evaluated using radiata pine sapwood, and treating characteristics in relation to different fluid phases and treatability were discussed. Various treatment conditions resulted in varying biocide retentions and distributions. Higher pressure conditions enhanced biocide retentions resulting from increasing biocide input in the applied saturation method. Subcritical CO2 condition produced higher biocide retentions and little retention gradients from face to core. Subcritical CO2 treatment has a couple of benefits such as investment costs and energy consumption compared with supercritical CO2.

Control of Diatrype stigma Occurred on the Bed-log of Shiitake Using Wood Vinegar, Plant Extracts and Fungicides

목초액, 잣나무추출물, 후추열매추출물 및 살균제를 이용해서 표고 골목에 발생하는 주홍꼬리버섯을 방제하고자 하였다. 식물추출물 선발시험결과, 목초액 35,000 ppm에서 균사생장이 완전히 억제되었고 25,000 ppm에서 자낭포자의 발아가 관찰되지 않았다. 그리고 잣나무추출물 200 ppm과 후추열매추출물 1,000 ppm에서 각각 98.9%와 95.9%의 자낭포자발아억제율을 보였다. 살균제 선발시험 결과, benomyl, carbendazim, thiabendazole 등의 최소억제농도(MIC)는

Comparative Study on The Composition of Essential Oil by Supercritical Carbon Dioxide Extraction and Hydro-distillation from Chamaecyparis obtusa Leaves

0{\sim}0.4\;{\mu}g\;a.i./m{\ell}

Structure Analysis of Water-soluble Polysaccharides Extracted from The Unripe Fruit of Cudrania tricuspidata

였다. Difenoconazole은

Inhibitory Effect of Extracts from Rhododendron Brachycarpum and Abies Koreana E.H. Wilson on Degranulation and Cytokine Expression in RBL-2H3 Cells

0.08%\;{\mu}g/m{\ell}

Alleviation effects of natural volatile organic compounds from Pinus densiflora and Chamaecyparis obtusa on systemic and pulmonary inflammation

농도에서 자낭포자 발아를 98.9% 억제했다. 살균제에 의한 표고균사생장억제율 조사 결과, 저온성, 중온성, 고온성균주 간에 차이가 거의 없는 것으로 나타났다. Benomyl, carbendazim, thiabendazole, thiophanate-methyl 등은 높은 농도에서도 비교적 낮은 억제율을 보였으나, tebuconazole은

Phanerochaete chrysosporium Multienzyme Catabolic System for in Vivo Modification of Synthetic Lignin to Succinic Acid

0.4\;{\mu}g\;a.i./m{\ell}