• Economic and Environmental Geology
• /
• v.36 no.5
• /
• pp.357-363
• /
• 2003

The objective of this study is to investigate background levels of As and heavy metals (Cd, Cu, Pb and Zn) and their dietary intakes from white rice produced at various provinces in Korea during 2000. Except Jeju-do, sixty-three rice grain samples were taken at 8 provinces and analyzed for the elements using ICP-AES after acid digestion. The average contents of hi, Cd, Cu, Pb and Zn in the samples were 0.126, 0.040, 1.96, 0.361 and 16.6 mg/kg(DW), respectively. These levels are within the ranges of worldwide average concentrations in rice grains reported by various research. Assuming the rice consumption of 256 g/day by overall households in Korea, the amount of daily intake of As, Cd, Cu, Pb and Zn by the rice were estimated to be 32.3, 10.2, 502, 92.4 and 4,250 ${\mu}g$/day, respectively. Those amount of daily intakes of the elements by the rice are within the WHO's guide for trace elements, however, rice consumption is one of the most important sources of dietary intake of As and some heavy metals in Korean population.

• Journal of Soil and Groundwater Environment
• /
• v.18 no.3
• /
• pp.23-32
• /
• 2013

Korean groundwater quality standards were established in 1994, and revised in 2003 and 2010. The substances for which standards have been developed are classified into two groups, general pollutants, 4, and specific pollutants, 15. The standards have been applied to household water use, agriculture, aquaculture, and industrial use. However, there is no systematic methodology for either selecting candidate substances or establishing groundwater standards. We investigated various derivation methodologies for groundwater standards used by the European Commission and 27 member states and compared their methods for determining threshold values. The European Commission presented to their member states groundwater standards for two substances and a list of required substances for derivation of threshold values along with the member states. Interestingly, they first considered national background levels and then considered other criteria for water protection, such as drinking water standards, environmental quality standards, and irrigation standards. We suggest that Korean background levels in groundwater should be included in the methodology for establishing groundwater quality standards. These results may be useful in developing a systematic methodology for establishing Korean groundwater quality standards.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.1 no.2
• /
• pp.102-109
• /
• 2006

In this paper, we improve the performance of bidirectional TCP connection over end-to-end network that uses transfer rate-based flow and congestion control. The sharing of a common buffer by TCP packets and acknowledgement has been known to result in an effect called ack compression, where acks of a connection arrive at the source bunched together, resulting in unfairness and degraded throughput. The degradation in throughput due to bidirectional traffic can be significant. For example, even in the simple case of symmetrical connections with adequate window size, the connection efficiency is improved about 20% for three levels of background traffic 2.5Mbps, 5.0Mbps and 7.5Mbps. Otherwise, the throughput of jitter is reduced about 50% because round trip delay time is smaller between source node and destination node. Also, we show that throughput curve is improved with connection rate algorithm which is proposed for TCP congestion avoidance as a function of aggressiveness threshold for three levels of background traffic 2.5Mbps, 5Mbps and 7.5Mbps.

• Atmosphere
• /
• v.28 no.4
• /
• pp.357-367
• /
• 2018

In this study, the temperature bias of aircraft observation was estimated through comparison with sonde observation prior to developing the temperature bias correction method at the Korea Institute of Atmospheric Prediction Systems (KIAPS). First, we tried to compare aircraft temperature with collocated sonde observations at 0000 UTC on June 22, 2012. However, it was difficult to estimate the temperature bias due to the lack of samples and the uncertainty of the sonde position at high altitudes. Second, we attempted a background innovation comparison for sonde and aircraft using KIAPS Package for Observation Processing (KPOP). The one month averaged background innovation shows the aircraft temperature have a warm bias against sonde for all levels. In particular, there is a globally distinct warm bias about 0.4 K between 200 hPa and 300 hPa corresponding to flight level. Spatially, most of the areas showed the warm bias except for below 300 hPa in some part of China at 0000 and 1200 UTC and below 850 hPa in Australia at 0000 UTC. In general, the temperature bias was larger at 1200 UTC than 0000 UTC. Based on the estimated temperature bias, we have applied the static bias correction method to the aircraft temperature observation. As a result, the warm bias of the aircraft temperature has decreased at most levels, but a slight cold bias has occurred in some areas.

• IMMUNE NETWORK
• /
• v.2 no.4
• /
• pp.223-226
• /
• 2002

Background: The type 2 deviated immunological state is predominant in lepromatous leprosy. Erythema nodosum leprosum (ENL) is an immune-complex mediated reaction that typically occurs in lepromatous leprosy. To date, the serum levels of tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-2 receptor, IL-10, IL-$1{\beta}$, IL-1 receptor antagonist and monocyte chemoattractant protein-1 (MCP-1) were reported to be higher in lepromatous leprosy. TNF-${\alpha}$ is also known to be higher in ENL, which is reduced after thalidomide treatment. However the serum type 2 chemokine levels in lepromatous leprosy patients have not been reported. Methods: The serum levels of the type 2 chemokines such as thymus and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC) and eotaxin together with IL-12 and IL-10 in the sera from leprosy patients were detected using an enzyme-linked solvent assay (ELISA) method. Results: The Serum TARC, MDC, eotaxin, IL-10 and IL-12 levels in lepromatous leprosy patients were not significantly different from the normal control levels. The serum levels were not significantly different between the paucibacillary group and multibacillary group. The serum TARC or MDC levels in the ENL patients were more reduced after a treatment containing thalidomide. Conclusion: The type 2 chemokines are not related to the severity of lepromatous leprosy. The larger reducing effect of the TARC or MDC levels in ENL patients by a treatment containing thalidomide suggests the potential role of these chemokines in the development of ENL and the therapeutic mechanism of thalidomide.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.4
• /
• pp.1617-1620
• /
• 2014

Background: Evidence shows direct link of HER2 to increased glycolysis and over production of lactate dehydrogenase (LDH). HER2 overexpression, high LDH and low glucose pleural levels are associated with poor prognosis in lung cancer. Here, their relationships were investigated. Materials and Methods: HER2 positivity was studied using immunohistochemistry in non-small cell lung cancer. Glucose and LDH levels were measured using commercial colorimetric kits. Results: Of 42 patients (29 adenocarcinoma and 13 squamous cell carcinoma), 28 (66.7%) were HER2-negative, 14 (33.3%) were HER2- positive, including 9 (21.4%) weakly stained (1+) and 5 (11.9%) moderately stained (2+) samples. The relationship between HER2 and glucose and LDH levels were tested in 20 newly diagnosed lung cancer patients who had simultaneous pleural and serum samples. Pleural and serum LDH levels were increased, and pleural glucose levels were decreased with the scale of HER2 positivity, and that the difference in glucose levels between HER2-negative group and HER2-positive patients scored at 2+ reached statistical significance (p=0.02). This latter group all had pleural glucose levels below 40 mg/dl. Conclusions: For the first time, we showed a significant association between low pleural glucose level and overexpression of HER2 in lung cancer. Further investigations are warranted to disclose the association of HER2 with low pleural glucose levels in other populations, with a larger sample size, in malignant pleural effusions caused by other types of cancer, and finally to assess employment as a screening tool for finding HER2-positive cases of lung cancer.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.7
• /
• pp.2965-2970
• /
• 2014

Background: To evaluate association of lung cancer with arsenic and cadmium levels measured in tumor tissue. Materials and Methods: Ninety-five patients with lung cancer tumor tissue obtained surgically were included in this study. Arsenic and cadmium levels were measured and levels of metals were compared among types of lung cancer and with reference to patient data. Results: The histopathologic diagnoses of the 95 cases were SCC, 49, adenocarcinoma, 28, large cell, 11 and SCLC, 1. Mean tumor arsenic and cadmium levels were $149.3{\pm}129.1{\mu}g/kg$ and $276.3{\pm}219.3{\mu}g/kg$, respectively. Cadmium levels were significantly associated with smoking (p=0.02), histopathologic type (p=0.005), and TNM staging (r=0.325; p=0.001), although arsenic was not related to any parameter (p>0.05). There was no relation between metal levels and mortality (p>0.05). Conclusions: We found a significant association between tumor cadmium levels of patients with lung cancer and smoking, histopathologic type and staging, although there was no relation with arsenic levels.

• Nutrition Research and Practice
• /
• v.11 no.4
• /
• pp.327-333
• /
• 2017

BACKGROUND/OBJECTIVES: Complications of diabetes, such as cardiovascular disease, are associated with increased mortality among type 2 diabetes mellitus patients. Homocysteine has been recently identified as a predictor of cardiovascular disease-related complications in diabetes. We investigated whether or not supplementation with folic acid tablets can lower homocysteine levels and improve parameters related with vascular complications. SUBJECTS/METHODS: We conducted a non-randomized 8-week trial involving postmenopausal diabetic women (n = 25) supplemented with $800{\mu}g$ of folic acid ($400{\mu}g$ twice a day) daily. Subjects' serum levels of folate, homocysteine, and vitamin $B_{12}$ were measured, along with vascular function and brachial-ankle pulse wave velocity. RESULTS: Folic acid supplementation significantly increased serum folate levels (P < 0.0001), reduced homocysteine levels (P < 0.0001), and increased vitamin $B_{12}$ levels (P = 0.0063). There were significant decreases in low-density lipoprotein cholesterol levels as well as the ratios of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol and total cholesterol to high-density lipoprotein cholesterol. Brachial-ankle pulse wave velocities were not altered by supplementation. Changes in serum vitamin $B_{12}$ after folic acid supplementation were negatively correlated with changes in brachial-ankle pulse wave velocity. CONCLUSIONS: In this study on postmenopausal Korean women with type 2 diabetes mellitus, folic acid supplementation reduced serum homocysteine levels, increased serum folate and vitamin $B_{12}$ levels, and lowered lipid parameters.

• Safety and Health at Work
• /
• v.5 no.4
• /
• pp.227-233
• /
• 2014

Background: The aims of this study were to determine hippuric acid levels in urine samples, airborne toluene levels, acute and chronic neurological symptoms, and to describe any correlation between urinary hippuric acid and airborne toluene. Methods: The hippuric acid concentration in the urine of 87 paint workers exposed to toluene at work (exposed group), and 87 nonexposed people (control group) was studied. Study participants were selected from similar factories in the same region. Urine samples were collected at the end of a shift and analyzed for hippuric acid by high performance liquid chromatography. Air samples for the estimation of toluene exposure were collected with diffusive personal samplers and the toluene quantified using gas-liquid chromatography. The two groups were also interviewed and observed about their work practices and health. Results: The median of the 87 airborne toluene levels was 55 ppm (range, 12-198 ppm). The median urinary hippuric acid level was 800 mg/g creatinine (range, 90-2547 mg/g creatinine). A statistically significant positive correlation was found between airborne toluene exposure and urine hippuric acid levels (r = 0.548, p < 0.01). Workers with acute symptoms had significantly higher hippuric acid levels than those who did not (p < 0.05). It was concluded that there was a significant correlation between toluene exposure, hippuric acid levels, and health (p < 0.001). Conclusion: There appears to be a significant correlation between workers exposure to toluene at work, their urine hippuric acid levels, and resulting symptoms of poor health. Improvements in working conditions and occupational health education are required at these workplaces. There was good correlation between urinary hippuric acid and airborne toluene levels.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.2
• /
• pp.301-308
• /
• 2002

As part of perfluorocarbon (PFC) tracer release experiment conducted at the western coastal area of Korea in February 2001, the background concentration level of perfluorocarbons (PFCs) in the atmosphere was determined by gas chromatography with electron capture detector. Prior to the PFC tracer release experiment in the field, air samples were collected using active samplers and the background concentrations of PFCs were determined. The concentrations of perfluoromethylcyclohexane ($C_7F_{14}$, PMCH) in the western coastal area of Korea were in the range of 5.8-8.7 fL/L. The mean concentration of the PMCH in the region exhibited no significant spatial and temporal variations. This concentration level is somewhat higher and has larger standard deviation than those of studies previously conducted in USA and Europe on the background concentration levels of PFCs. Because the background concentration of PMCH in Korea is still very low and consistent temporally and spatially, the PMCH tracer can be used suitably for the studies of long-range atmospheric transport.