3.Pumpless individual sampling gas chromatography for determination of dichloromethane in air of working places.
Jian-guo LI ; Hao LI ; Tong LIU
Chinese Journal of Industrial Hygiene and Occupational Diseases 2008;26(2):108-109
Air
;
analysis
;
Chromatography, Gas
;
methods
;
Methylene Chloride
;
analysis
;
Workplace
4.Effect of denture base surface pretreatments on the tensile bond strength between a resilient liner and a processed denture base resin.
Min Chul YOON ; Chang Mo JEONG ; Young Chan JEON
The Journal of Korean Academy of Prosthodontics 2007;45(5):621-632
STATEMENT OF PROBLEM: The failure of adhesion between the resilient denture liner and the denture base is a serious problem in clinic. PURPOSE: The PURPOSE of this study was to evaluate the effect of denture base resin surface pretreatments (mechanical and/or chemical) on the tensile bond strength between a resilient liner and processed denture resin. MATERIAL AND METHOD: Acrylic-based resilient liners (Soft liner; GC co., Japan & Coe-Soft; GC America Inc. USA) and silicone-based resilient liners (Mucosoft; Parkell Inc., USA & Dentusil; Bosworth co., USA) were used. Specimens in each soft lining material were divided two groups with or without mechanical pretreatment. Each denture base specimen received 1 of 4 chemical pretreatments including: (1) no treatment, (2) 30-s acetone treatment, (3) 15-s methylene chloride treatment, (4) 180-s methyl methacrylate treatment. All specimens were thermocycled and placed under tension until failure in a universal testing machine. RESULTS: 1. Silicone-based resilient liners exhibited significantly higher tensile bond strengths than acrylicbased resilient liners (P<.05). 2. Grinding the denture base resin improved tensile bond strengths of silicone-based resilient liners, but reduced tensile bond strengths of acrylic-based resilient liners (P<.05). 3. In acrylic-based resilient liners, treating with acetone significantly increased the bond strength of Soft liner and treating with methyl methacrylate significantly increased the bond strength of Coe-Soft (P<.05). However they were not effective compared to silicone-based resilient liner. 4. In silicone-based resilient liners, treating with all chemical etchants significantly increased the bond strength of Mucosoft to denture base, and treating with methylene chloride and methyl methacrylate increased the bond strength of Dentusil to denture base (P<.05). CONCLUSION: Although chemical and mechanical pretreatments were not effective on tensile bond strength of acrylic-based resilent liner to denture base, treating the denture base resin surface with appropriate chemical etchants after mechanical pretreatment significantly increased the tensile bond strength of silicone-based resilient liner to denture base.
Acetone
;
Americas
;
Denture Bases*
;
Denture Liners
;
Dentures*
;
Japan
;
Methylene Chloride
5.Cultural Characteristics of Vibrio vulnificus on Various Media.
Korean Journal of Dermatology 1987;25(2):193-198
Using the 15 strains of Vibrio eulnificus isolated from the blood and tissue fluid of the patients with primary septicemia, cultural characteristics were studied on various media. The media to be used in culturing Vibrio vulnificus should contain sodium chloride, because it could not survive on the media without NaCl. The organism grew poorly or not at all on the media with eosin-y, methylene blue, crystal violet, or azide, because these substances suppress its growth. Vibrio vulnificus grew well in the enrichment media such as brain heart infusion, tryptic soy broth, and nutrient broth with 0. 5% NaCl.
Brain
;
Cultural Characteristics*
;
Gentian Violet
;
Heart
;
Humans
;
Methylene Blue
;
Sepsis
;
Sodium Chloride
;
Vibrio vulnificus*
;
Vibrio*
7.Determination of oxide, furan, dichloromethane by portable gas chromatography.
Zheng RUAN ; Hong-fang TANG ; Dan-hua LIU ; Hai-bao ZHU ; Han WANG ; Ya-ling QIAN
Chinese Journal of Industrial Hygiene and Occupational Diseases 2013;31(11):868-870
Air
;
analysis
;
Chromatography, Gas
;
methods
;
Ethylene Oxide
;
analysis
;
Furans
;
analysis
;
Methylene Chloride
;
analysis
;
Workplace
8.Bioassay-Guided Isolation and Identification of Compounds from Arecae Pericarpium with Anti-inflammatory, Anti-oxidative, and Melanogenesis Inhibition Activities.
Amelia INDRIANA ; Kyoung Jin LEE ; Yeong Shik KIM
Natural Product Sciences 2016;22(3):193-200
This study describes the anti-inflammatory, anti-oxidant, and melanogenesis inhibition activities of methanol extract and various organic solvent fractions of Arecae Pericarpium. We examined the inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 cells, 1,1-diphenyl-2-picrylhydrazine (DPPH) scavenging activity, mushroom tyrosinase inhibition activity and melanin contents. The study showed that, among all tested fractions, methylene chloride fraction showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells (IC₅₀ value 8.89 µg/mL) and DPPH radical scavenging activity (EC₅₀ value 21.39 µg/mL). Methylene chloride and ethyl acetate fractions similarly inhibited mushroom tyrosinase activity. Methanol extract exhibited strongest reduction of melanin content in B16F10 melanoma cells. Based on the bioactivity assay results, methylene chloride and ethyl acetate fractions were further separated. Eight phenolic compounds were isolated, which are dimeric syringol (1), catechol (2), 4-hydroxybenzaldehyde (3), vanillin (4), 4-hydroxyacetophenone (5), apocynin (6), protocatechuic acid (7) and 4-hydroxybenzoic acid (8). Among the isolated compounds tested, catechol showed the strongest inhibition of LPS-induced NO production in RAW 264.7 cells. Catechol also showed the concentration-dependent NF-κB inhibition activity. Arecae Pericarpium might have potentials to be developed as anti-inflammatory agent or dermatological product for skin-whitening agent.
Agaricales
;
Areca*
;
Melanins
;
Melanoma
;
Methanol
;
Methylene Chloride
;
Monophenol Monooxygenase
;
Nitric Oxide
;
Phenol
;
RAW 264.7 Cells
9.Effects of Dichloromethane Fraction of Phlomidis Radix on Bone Formation in Human Fetal Osteoblasts.
Young Joon LEE ; Hee In CHOI ; Yun Chul KIM ; Hyung Keun YOU ; Hyung Shik SHIN
The Journal of the Korean Academy of Periodontology 2003;33(2):259-269
The ideal goal of periodontal therapy is the regeneration of periodontal tissue and repair of function. Although it is very difficult to attain this goal, recent advances in periodontal wound healing concepts encourage hope reaching it. Recently many efforts are concentrated on the regeneration potential of material used in traditional Korean medicine. Phlomidis Radix has been used for the treatment of blood stasis, bone fracture and osteoporosis in traditional Korean medicine. The purpose of this study is to examine effects of dichloromethane fraction Phlomidis Radix on Bone Formation in Human Fetal Osteoblasts. Human fetal osteoblastic cell line(hFOB1 1.19 ; American Type Culture Collection, Manassas, VA) were used and cells were cultured containing DMEM and dichloromethane fraction Phlomidis Radix(100 ng/ml, 1 microgram/ml, 10 microgram/ml) at 34degrees C with 5% CO2 in 100% humidity. MTT was performed to examine the viability of the cell, and alkaline phosphatase activity was analyzed to examnine the mineralization. Also bone calcification nodules were evaluated. The cellular activity of hFOB1 was increased in 100 ng/ml, 1 microgram/ml, 10 microgram/ml of dichloromethane fraction of Phlomidis Radix and especially significant increation was showed in 100 ng/ml of dichloromethane fraction of Phlomidis Radix at 6days (p<0.05). ALP level of hFOB1 was significantly increased in 100 ng/ml, 1 microgram/ml, 10 microgram/ml of dichloromethane fraction of Phlomidis Radix and especially more increation was showed in 10 microgram/ml of dichloromethane fraction of Phlomidis Radix (p<0.05). Calcification nodules of hFOB1 significantly increased in 10 microgram/ml of dichloromethane fraction of Phlomidis Radix at 21days of incubation (p<0.05). These results indicate that dichloromethane fraction of Phlomidis Radix has excellent effects on mineralization of hFOB1.
Alkaline Phosphatase
;
Fractures, Bone
;
Hope
;
Humans*
;
Humidity
;
Methylene Chloride*
;
Osteoblasts*
;
Osteogenesis*
;
Osteoporosis
;
Regeneration
;
Wound Healing
10.A Study on Worker Exposure to Methylene Chloride in Aircraft Paint Stripping Operation.
Seung Won KIM ; Chae Young LEE ; Tae Hyung MIN
Korean Journal of Aerospace and Environmental Medicine 2001;11(1):20-23
BACKGROUND: Workers who are related with paint stripping process of aircraft parts can be exposed methylene chloride, phenol, chromium hexavalent in using paint remover. Especially, methylene chloride is more important hazard because of chemical asphyxia. METHOD: NIOSH(National Institute of Occupational Safety and Health) Manual of Analytical Methods(NMAM) #1005 was used in sampling and analysis of methylene chloride. 4 air bases were surveyed. RESULT: Airborne concentrations of methylene chloride distributed lognomally. In aircraft paint stripping operation of 4 air bases, geometric mean(GM) of methylene chloride concentrations was 30.40+/-3.39 ppm (n=14) in personal samples and GM of area samples was 2.24 ppm (n=2). 5 of 8 samples showed breakthrough phenomenon. Breakthrough rate([back section]/[front section]) significantly correlated with airborne concentrations (p<0.01) and with detected amounts of methylene chloride(p<0.01). CONCLUSION: Airborne concentrations of methylene chloride in paint stripping process exceed the criteria level in many case(43%). Seriesed charcoal tubes must be used in methylene chloride sampling in compliance with NMAM.
Aircraft*
;
Asphyxia
;
Charcoal
;
Chromium
;
Compliance
;
Humans
;
Methylene Chloride*
;
Occupational Health
;
Paint*
;
Phenol