• Asian Pacific Journal of Cancer Prevention
• /
• 제15권5호
• /
• pp.2287-2290
• /
• 2014

Background: In the past few years, a considerable number of preclinical studies have been proposed metformin as a potential anticancer agent, but some of these studies suffer from a number of methodological limitations such as assessment of cytotoxicity in the presence of supraphysiological glucose concentrations or applying suprapharmacological levels of the drug. These objections have limited the translation of published preclinical data to the clinical setting. The present study aimed to investigate direct anticancer effects of metformin on different molecular subtypes of breast cancer with pharmacological concentrations and under normoglycemic conditions in vitro. Materials and Methods: Breast cancer cell lines from luminal A, luminal B, ErbB2 and triple-negative molecular subtypes were treated with a pharmacological concentration of metformin (2mM) at a glucose concentration of 5.5mM. Time-dependant cell viability was assessed by dye exclusion assay. MTTbased cytotoxicity assays were also performed with metformin alone or in combination with paclitaxel. Results: Metformin did not show any growth inhibitory effects or time-dependant cytotoxicity on breast cancer cell lines in the presence of normal glucose concentrations at the therapeutic plasma level. No augmentation of the antineoplastic properties of paclitaxel was apparent under the tested conditions. Conclusions: Metformin is probably unable to exert cytotoxic or cytostatic effects on breast cancer subtypes at pharmacological concentrations and normal plasma glucose levels. These results highlight the importance of establishing a higher steady-state plasma concentration of metformin in the clinical setting for assessment of anticancer effects in normoglycemic patients.

• 한국대기환경학회지
• /
• 제34권1호
• /
• pp.166-176
• /
• 2018

The n-alkanes which are stable compounds in the atmosphere are emitted by anthropogenic sources and biological sources. The goal of this study is to understand characteristics of n-alkane distributions in $PM_{2.5}$ of the Anmyeon Island which is one of background site in Korea. The concentration of n-alkanes in $PM_{2.5}$ was measured at Anmyeon Island for one year from June 2015 to May 2016. The average concentration of total n-alkanes (${\sum}$ n-alkanes) from C20 to C34 was $14.02{\pm}10.26ng\;m^{-3}$ and ranged from 1.77 to $47.65ng\;m^{-3}$. Various diagnostic parameters were used to identify the source. As a result, it is considered that Anmyeon Island had a large influence of biological sources during non-heating period, while the influence of anthropogenic emission during the heating period was significant. Principle Component Analysis (PCA) was performed and yielded three components that accounted for 93.6% of the total variance in n-alkanes. Factor 1, which accounted for 42.3% of the total variance, indicated anthropogenic source including fossil fuel and biomass combustion, while, Factor 3 was interpreted as the biological sources such as plant wax.

• 한국환경농학회지
• /
• 제39권3호
• /
• pp.197-203
• /
• 2020

BACKGROUND: Most lakes have increased concerns about water pollution due to the inflow of non-point sources caused by human activities. Therefore, the lake water quality survey was conducted in order to propose effective plans for water quality management by analyzing the characteristics of lakes and the change of water quality. METHODS AND RESULTS: In order to investigate the physicochemical water quality in Daedong lake, water quality analysis was undertaken from July 2018 to June 2019. Water temperature was ranged from 7.8 to 34.3℃ and pH varied from 6.9 to 10.2. The concentration of Dissolved oxygen, Suspended solid, Biochemical Oxygen Demand (BOD), and Chemical Oxygen Demand (COD) were 5.6 ~ 17.2 mg/L, 2.4 ~ 35.3 mg/L, and 4.5 ~ 15.1 mg/L, and 0.9 ~ 2.8 mg/L, respectively. The Total Nitrogen (T-N) concentration ranged from 0.974 ~ 2.126 mg/L, and Total Phosphorus (T-P) concentration ranged from 0.014 ~ 0.057 mg/L. The Chlorophyll-a (Chl-a) ranged from 2.7 ~ 37.9 mg/㎥. Through Carlson TSIm assessment using T-P and Chl-a results, evaluating trophic state, Daedong lake was evaluated as mesotrophic. CONCLUSION: Water pollution management plan needs such as nutrient removal technology and nonpoint source management for prevention of eutrophication in Daedong lake.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제15권6호
• /
• pp.81-90
• /
• 2010

In this study, primary investigation for evaluation of abandoned metal mine effect on watershed has been done. 64 abandoned mines have been selected for primary investigation through literature and field survey. 216 soil and 90 water samples were collected and metal pollution concentrations were analyzed. 24 mines have mine water in the pits and acid water below pH 5 was not observed. Soils from 35 mines were over the soil basis of concern and 16 mines were over the soil basis of action. Arsenic average concentration was 188 times of average concentration of the natural background. Drinking water samples from 3 mines were over the drinking water standard and surface water samples from 12 mines were over the river water standard. Integrated pollution index, which was resulted from the integration of field survey, soil and water pollution concentration, showed that, abandoned metal mines had affected on watershed greatly in the order of Samgeum, Daedeok, Cheongdalgeum, Heungsin, Yeongdae and Myeongbong mines.

• Journal of Ginseng Research
• /
• 제40권3호
• /
• pp.229-236
• /
• 2016

Background: Extraction conditions greatly affect composition, as well as biological activity. Therefore, optimization is essential for maximum efficacy. Methods: Korean Red Ginseng (KRG) was extracted under different conditions and antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content evaluated. Optimized extraction conditions were suggested using response surface methodology for maximum antioxidant activity and extraction yield. Results: Analysis of KRG extraction conditions using response surface methodology showed a good fit of experimental data as demonstrated by regression analysis. Among extraction factors, such as extraction solvent and extraction time and temperature, ethanol concentration greatly affected antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content. The optimal conditions for maximum antioxidant activity and extraction yield were an ethanol concentration of 48.8%, an extraction time 73.3 min, and an extraction temperature of $90^{\circ}C$. The antioxidant activity and extraction yield under optimal conditions were 43.7% and 23.2% of dried KRG, respectively. Conclusion: Ethanol concentration is an important extraction factor for KRG antioxidant activity and extraction yield. Optimized extraction conditions provide useful economic advantages in KRG development for functional products.

• 기술혁신학회지
• /
• 제13권2호
• /
• pp.282-309
• /
• 2010

최근 기술무역에 의한 기술도입은 글로벌 시대에서 핵심적인 기술혁신전략이라고 할 수 있으며, 기술도입의 현황분석을 통해 국가의 기술정책을 수립하는 것은 국가경쟁력 확보에 매우 중요한 요소라고 볼 수 있다. 그러나 기술무역에 대한 연구들의 대부분은 기술무역의 특성파악과 거시적인 현황 및 파급 효과분석에만 초점을 맞추고 있어, 실질적으로 국가의 정책을 수립하는 데에는 이론적/실무적 배경을 제시하지 못하고 있는 실정이다. 따라서 본 연구에서는 한국은행의 '기술도입대가 지급현황' 데이터를 활용하여 지식경제부의 통합기술청사진에서 사전에 정의된 31개 중점기술분야에 대해 기술집중도, 기업집중도, 국가집중도를 분석하고, 기술별 거래되는 기술유형과 기술도입거래대가 유형을 분석하였다. 이를 통해, 기술분야별로 기술거래가 특정 하위기술, 기업, 국가에 집중되는 정도를 분석하고, 기술거래유형의 특성을 분석하여 국내산업의 기술도입 특성을 도출하였다. 본 연구의 결과는 국가에서 기술의 수출 및 수입에 관련된 기술정책을 수립하는 영역에서 뿐만 아니라 국내산업의 기술혁신 특성을 분석하기 위한 중요한 자료로 활용될 수 있을 것이다.

• Journal of Ginseng Research
• /
• 제39권4호
• /
• pp.304-313
• /
• 2015

Background: Ginsenoside Rg3 is a promising anticancer agent. It is usually produced by heat treatment of ginseng, in which ginsenoside Rb1 is the major ginsenoside. A kinetic study was conducted to optimize ginsenoside Rg3 production by the heat treatment of ginsenoside Rb1. Methods: Ginsenoside Rb1 was heated using an isothermal machine at $80^{\circ}C$ and $100^{\circ}C$ and analyzed using HPLC. The kinetic parameters were calculated from the experimental results. The activation energy was estimated and used to simulate the process. The optimized parameters of ginsenoside Rg3 production are suggested based on the simulation. Results: The rate constants were $0.013h^{-1}$ and $0.073h^{-1}$ for the degradation of ginsenosides Rb1 and Rg3 at $80^{\circ}C$, respectively. The corresponding rate constants at $100^{\circ}C$ were $0.045h^{-1}$ and $0.155h^{-1}$. The estimated activation energies of degradation of ginsenosides Rb1 and Rg3 were 69.2 kJ/mol and 40.9 kJ/mol, respectively. The rate constants at different temperatures were evaluated using the estimated activation energies, and the kinetic profiles of ginsenosides Rb1 and Rg3 at each temperature were simulated based on the proposed kinetic model of consecutive reaction. The optimum strategies for producing ginsenoside Rg3 from ginsenoside Rb1 are suggested based on the simulation. With increased temperature, a high concentration of ginsenoside Rg3 is formed rapidly. However, the concentration decreases quickly after the reaching the maximal concentration value. Conclusion: The optimum temperature for producing ginsenoside Rg3 should be the highest temperature technically feasible below $180^{\circ}C$, in consideration of the cooling time. The optimum reaction time for heat treatment is 30 min.

• Journal of Dental Anesthesia and Pain Medicine
• /
• 제15권2호
• /
• pp.69-76
• /
• 2015

Background: There have been few studies on the effect of an elevated concentration of lidocaine hydrochloride in the surgical removal of an impacted lower third molar. This study aimed to examine the efficacy of 4% lidocaine along with 1:100,000 epinephrine compared to 2% lidocaine along with 1:100,000 epinephrine as inferior alveolar nerve block for the removal of an impacted lower third molar. Methods: This single-blind study involved 31 healthy patients (mean age: 23 y; range: 19-33 y) with symmetrically impacted lower third molars as observed on panoramic radiographs. Volunteers required 2 surgical interventions by the same surgeon with a 3-week washout period. The volunteers were assigned either 4% lidocaine with 1:100,000 epinephrine or 2% lidocaine with 1:100,000 epinephrine as local anesthetic during each operation. Results: We recorded the time of administration, need for additional anesthetic administration, total volume of anesthetic used. We found that the patient's preference for either of the 2 types of local anesthetic were significantly different (P < 0.05). However, the extent of pulpal anesthesia, surgical duration, and duration of soft tissue anesthesia were not significantly different. Conclusions: Our study suggested that inferior alveolar nerve block using 4% lidocaine HCl with 1:100,000 epinephrine as a local anesthetic was clinically more effective than that using 2% lidocaine HCl with 1:100,000 epinephrine; the surgical duration was not affected, and no clinically adverse effects were encountered.

• Journal of Dental Anesthesia and Pain Medicine
• /
• 제20권3호
• /
• pp.137-146
• /
• 2020

Background: Mandibular third molar removal is the most common surgical procedure encountered in oral and maxillofacial clinics. It also presents the greatest challenges and controversies for surgeons when surgical removal is considered. Furthermore, diverse anesthesia results and success rates are achieved after using the same concentrations of different solutions or the same amounts of local anesthetics. The purpose of this study was to examine the efficiency of using double-cartridge (3.4 ml) 4% lidocaine (high concentration) and 4% articaine with a 1:100000 epinephrine infiltration in the retromolar region for impacted lower third molar surgery. Methods: This double-blind study included 30 patients with symmetrically impacted lower third molars. The patients were randomly selected to receive 4% articaine on one side and 4% lidocaine on the other, as a local anesthetic for third molar surgery. The onset, duration of soft-tissue numbness, pulpal sensitivity, amount of additional local anesthetic needed, pain score during the surgical procedure, and duration of the operation were recorded. Results: The results of this research indicate that 86.7% of the operations in the 4% articaine group and 83.3% of those in the 4% lidocaine group were successful. Furthermore, the outcomes in both groups were not statistically significant (P > 0.05). Numbness onset occurred faster in the articaine group than it did in the lidocaine group. However, the duration of soft-tissue anesthesia and pain scores recorded immediately postoperatively were similar. Conclusion: It is concluded that 4% lidocaine and 4% articaine had a similar infiltration efficacy in the retromolar region and both local anesthetics are adequate for impacted lower third molar surgery. There were no statistically significant differences between the two local anesthetics regarding pain control and the duration of soft-tissue numbness during the procedure.

• Nutrition Research and Practice
• /
• 제13권2호
• /
• pp.115-125
• /
• 2019

BACKGROUND/OBJECTIVES: Vitamin D plays an important role in skeletal growth and maintenance and in the prevention of various diseases. We investigated the relationship between vitamin D intake and bone mineral density (BMD) in Korean adults aged ${\geq}50$ years using the 2009 Korea National Health and Nutrition Examination Survey data. SUBJECTS/METHODS: This study was conducted in 1,808 subjects aged ${\geq}50$ years with BMD data in Korea. Dietary vitamin D levels were assessed by the 24-hour recall method. BMD was measured using dual-energy X-ray absorptiometry. We investigated general characteristics and the association between these characteristics, vitamin D status, and BMD. RESULTS: Vitamin D intake was significantly lower in the osteoporosis group among women (P < 0.05). Among all subjects, the higher the serum 25(OH)D concentration, the higher the whole-body total BMD (WBT-BMD), femoral total hip BMD, and femoral neck BMD (P < 0.01). In the serum vitamin D-deficient group of both the total population and women, serum 25(OH)D concentration was associated with WBT-BMD (P < 0.05). Among women with a calcium intake < 537.74 mg/day, BMD of those with a vitamin D intake > $2.51{\mu}g/day$ (average intake of women) was higher than that of women with a vitamin D intake ${\leq}2.51{\mu}g/day$ (P < 0.001). CONCLUSIONS: Korean adults should increase their BMD by increasing serum 25(OH)D concentration. Furthermore, increasing vitamin D intake could improve BMD, especially in Korean women who consume less calcium than the estimated average requirement.