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호앙구엔 ( Dung H. Nguyen ),민은엔 ( Duc T. M. Nguyen ),라련화 ( Lyun Hwa La ),이향복 ( Hyang Bok Lee ),신정현 ( Jung Hyun Shin ),김은기 ( Eun Ki Kim ) 대한화장품학회 2008 대한화장품학회지 Vol.34 No.3
미백제를 선발하기 위해 주로 사용하는 현재의 방법은 in vitro 타이로시네이즈 활성 및 항산화능을 측정하는 것이다. 이 결과에 기초하여 다음 단계인 멜라노사이트에서의 멜라닌 생성량을 측정한다. 세포 내의 멜라닌 생성량 측정법은 시간, 인력 및 숙련도가 요구된다. 따라서 초기 선발 방법의 신뢰성이 중요하다. 200개 중국시료 중 측정범위 내에서 세포독성이 없는 34개를 대상으로 세포 내 멜라닌량, 타이로시네이즈 활성, 항산화능의 상관관계를 조사하였다. 조사결과 직선의 상관관계를 확인할 수 없었다. 이 결과는 현재 선발방법의 한계 및 새로운 방법이 필요함을 보여주었다. Initial screening assay for depigmenting agents includes in vitro mushroom tyrosinase assay and antioxidant assay. Based on this screening result, melanin synthesis in melanocyte, in screened samples, is further measured. Measuring cellular melanin needs time, human resource, and skills. Therefore initial screening method should be reliable. We examined 34 Chinese herbs, correlated the screening assay methods with cellular melanin. No reliable relationship was observed between factors, indicating the limitation in the use of these assays, probably due to the complexicity of melanogenesis.
Sumathy Babitha,Dung H. Nguyen,Sang-Joo Park,Eun-Ki Kim,신정현,Gaudelia A. Reyes,Adeltrudes Caburian 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.6
In vitiligo, active melanocytes in the epidermis are not present, whereas melanoblast cells in the outer root sheath of hair follicles are not affected. The existence of these inactive melanocytes provides a source for repigmentation of vitiligo. To evaluate the potential of herbal candidates in treatment of vitiligo, we studied the effect of Cassia alata leaf extract on the differentiation, proliferation and migration of melanoblast cells. Melanin content increased in melb-a melanoblast cells in response to this herb extract in a dose-dependent manner compared to control cells. In addition, it induced tyrosinase activity and altered melb-a cell morphology. A transwell migration assay showed the potential of this herbal candidate to induce direct migration of treated cells. To our knowledge, this is the first report on activity of this kind in Cassia alata. The findings of the present study are significant in the direction of developing safer strategies for vitiligo treatment.
Youna K. Choi,Danielle H. Rochlin,Dung H. Nguyen 대한성형외과학회 2020 Archives of Plastic Surgery Vol.47 No.5
Background This study evaluated the Blossom system, an innovative self-filling, rate-controlled, pressure-responsive saline tissue expander (TE) system. We investigated the feasibility of utilizing this technology to facilitate implant-based and combined flap with implant-based breast reconstruction in comparison to conventional tissue expansion. Methods In this prospective, single-center, single-surgeon pilot study, participants underwent either implant-based breast reconstruction or a combination of autologous flap and implantbased breast reconstruction. Outcome measures included time to full expansion, complications, total expansion volume, and pain scores. Results Fourteen patients (TEs; n=22), were included in this study. The mean time to full expansion was 13.4 days (standard error of the mean [SEM], 1.3 days) in the combination group and 11.7 days (SEM, 1.4 days) in the implant group (P=0.78). The overall major complication rate was 4.5% (n=1). No statistically significant differences were found in the complication rate between the combination group and the implant group. The maximum patient-reported pain scores during the expansion process were low, but were significantly higher in the combination group (mean, 2.00±0.09) than in the implant group (mean, 0.29±0.25; P=0.005). Conclusions The reported average duration for conventional subcutaneous TE expansion is 79.4 days, but this pilot study using the Blossom system achieved an average expansion duration of less than 14 days in both groups. The Blossom system may accommodate single-stage breast reconstruction. The overall complication rate of this study was 4.5%, which is promising compared to the reported complication rates of two-stage breast reconstruction with TEs (20%–45%).
Effects of di-(2-ethylhexyl) phthalate (DEHP) released from laboratory equipments
Eun-Ki Kim,Dung H. Nguyen,Duc T. M. Nguyen 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.5
Di-(2-ethylhexyl) phthalate (DEHP) is a plasticizer used in polyvinyl chloride (PVC) manufacturing and is an endocrine disrupter. DEHP was released from laboratory tubing and resins during solvent extraction of natural plants to isolate skin depigmenting compounds. Contamination of DEHP significantly interfered with the purification of depigmenting compounds, since DEHP showed high depigmenting activity (IC50=24 μM) and did not show cell toxicity up to 20 μM. Release of DEHP depended on the composition of tubing materials and solvents used in the extraction process. This result provides practical information for the proper selection of laboratory materials and solvents especially in the extraction and isolation of skin depigmenting compounds for cosmetic ingredients.