• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.1
• /
• pp.53-57
• /
• 2009

Heavy metal pollution may be one of the most serious challenges confront crop production and human health. Therefore, the selection of heavy metal tolerance cultivars which adapted to the contaminated fields will introduced a suitable solution for management this critical environmental risk. The objectives of this research is to assess human health risk using geochemical analyses and exposure assessment of heavy metals in rice cultivars. Risk for inhabitants in the closed mine area was comparatively assessed for As, Cd, Cu and Pb in 10 rice varieties as a major exposure pathway. The average daily dose (ADD) of each heavy metal was estimated by analyzing the exposure pathways to rice and soil. For the non-carcinogenic risk characterization, Hazard Quotient (HQ) and Hazard Index (HI) were calculated using toxicity indices provided by US-EPA IRIS. The different rice varieties revealed a wide range of HI values from 23.6 to 34.3, indicating that all rice varieties have a high potential toxic risk. The DA rice variety showed the lowest HI value while the TB rice variety the highest. The probabilities of cancer risk for As via rice consumption were varied with rice varieties ranging from 2.0E-03 to 3.5E-03 which exceeded the regulatory acceptable risk of 1 in 10,000 set by US-EPA. The DA rice variety also showed the lowest value while the TB rice variety gave the highest value. Our results indicate that risk assessment can be contribute to screen the pollution safe rice cultivars in paddy fields affected by the mining activity.

• Journal of Bio-Environment Control
• /
• v.31 no.3
• /
• pp.194-203
• /
• 2022

Cultivation of tomatoes in Korea grown in soil covers 89% of the total area for tomato cultivation. Tomatoes grown in soil often encounter various environment stresses including not only salt stress and soil-borne diseases but also cold stress in the winter season. This study was conducted to comparatively analyze the performance of rootstocks with cold stress by measuring the growth, yield, and photosynthetic efficiency in tomatoes grown in soil. The rootstocks were used 'Powerguard', 'IT173773', and '20LM' for the domestic rootstock cultivars and 'B-blocking' for a control cultivar. The tomato cultivar 'Red250' was used as the scion and the non-grafted tomatoes. Stem diameter, flowering position, leaf length, and leaf width were investigated for the growth parameters. The stem diameter of the non-grafted tomatoes decreased by 15% compared to the grafted tomatoes at 80 days after transplanting when exposed to low temperatures of 9-14℃ for 14 days. The leaf length and width of the non-grafted tomatoes were the lowest with 42.4 cm and 41.8 cm at 80 days after transplanting. The total yield per plant was the highest in tomato plants grafted on 'Powerguard' with 1,615 g and lowest in non-grafted tomatoes with 1,299 g. As the result of measuring the chlorophyll fluorescence parameters, PI_ABS and DI₀/RC, which mean the performance index and dissipated energy flux, 'Powerguard' was the highest with 3.73 in PI_ABS and the lowest with 0.34 in DI₀/RC, whereas non-grafted tomatoes was the lowest with 2.62 in PI_ABS and the highest with 0.41 in DI₀/RC at 80 days after transplanting. The stem diameter has positive correlation with PI_ABS, while it has negative correlation with DI₀/RC. The results indicate that can be analyzed by chlorophyll fluorescence parameters can be used for analyzing the differences in the growth of tomato plants grafted on different rootstocks when exposed to cold stress.

• Journal of Korean Society of Forest Science
• /
• v.112 no.4
• /
• pp.417-425
• /
• 2023

The aim of this study was to derive stem taper equations for Quercus acuta, one of main evergreen broad-leaved tree species found in warm temperate regions, and to prepare a stem volume table using those stem taper equations. A total of 688 individual trees were used in the analysis, which were collected from Jeonnam-do, Gyeongnam-do, and Jeju-do. The stem taper models applied to derive the stem curve pattern were the Max and Burkhart, Kozak, and Lee models. Among the three stem taper models, the best explanation of the stem curve shape of Q. acuta was found to be given by the Kozak model, which showed a fitness index of 0.9583, bias of 0.0352, percentage of estimated standard error of 1.1439, and mean absolute deviation of 0.6751. Thus, the stem taper of Q. acuta was estimated using the Kozak model. Moreover,thestemvolumecalculationwasperforme d by applying the Smalian formula to the diameter and height of each stem interval. In addition, an analysis of variance (ANOVA) was conducted to compare the two existing Q. acuta stem volume tables (2007 and 2010) and the newly created stem volume table (2023). This analysis revealed that the stem volume table constructed in the Wando region in 2007 included about twice as much as the stem volume tables constructed in 2010 and 2023. The stem volume table (2023) developed in this study is not only based on the regional collection range and number of utilized trees but also on a sound scientific basis. Therefore, it can be used at the national level as an official stem volume table for Q. acuta.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.30 no.2
• /
• pp.165-173
• /
• 1985

The objectives of the study were to investigate the effects of foliage clipping on photosynthesis and grain filling for branch and non branch types under the polyethylene film mulch and non mulch conditions in mono cropping and second cropping after barley in sesame (Sesamum indicum L.), and to improve poor grain filling at later flowering time utilizing these data. One thousand grain weight was more decreased in branch type than in non branch type, in polyethylene film mulch condition than in non mulch condition, and in second cropping after barley than in mono cropping by clipping lower part foliage. Twentyfive percent clipping of lower part foliage showed a little increase than no clipping. Matured grain rate also showed same tendency between branch and non branch type and between mono cropping and second cropping after barley as well as 1,000 grain weight except for polyethylene film mulch. Matured grain rate of 25% foliage clipping at 30 days after flowering in non branch type presented a little increase but decreased in branch type. Clipping of higher part leaves were so serious decrease of matured grain rate that higher part leaves at late maturing time have a major role in photosynthesis. Matured grain rate of foliage clipping at 10 days after flowering was decreased in all treatments. Chlorophyll content of higher part leaves at 50% lower part foliage clipping presented 39% increase compared to same positioned leaves of non treatment, and 66% increase by 50% higher part foliage clipping in lower part leaves. Photosynthetic activity was 58% more increased in 50% lower part foliage clipping than no clipping, but seriously decreased in 50% higher part foliage clipping. Therfore, photosynthates of remained lower part leaves could not only support their own demands, but also any contribution to translocation of photosynthates from source to sink at late maturing time. Harvest index was 28% increased in 25% lower part foliage clipping and 13% decreased in 50% higher part foliage clipping compared to no clipping. Leaf area was 48% increased in 50% lower part foliage clipping compared to the same positioned leaves of no clipping, and only 5% increased in higher part foliage clipping. Productivity by foliage clipping compared to non treatment, was highly decreased in branch type than in non branch type, in second cropping after barley than in mono cropping. Little difference was detected between polyethylene film mulch and non mulch conditions. Twenty five percentage of lower part foliage clipping on mono cropping of non branch type appeared 5% and 8% yield increase in each of polyethylene film mulch and non mulch conditions compared to no clipping, and all decreased in other treatments. Mean loss of productivity by foliage clipping at 10 days after flowering was serious than clipping at 30 days after flowering. As the result, contribution to photosynthesis of source at 10 days after flowering are larger than that at 30 days after flowering in sesame. Fifty percent lower part foliage clipping at 10 days after flowering showed so the most serious yield decrease that lower part leaves at that time were considered as the main role leaves for photosynthesis.

• Korean Journal of Psychosomatic Medicine
• /
• v.28 no.1
• /
• pp.42-52
• /
• 2020

Objectives : Firefighters are always under stress due to their job environment, and they are likely to become psychologically vulnerable due to continuous exposure to traumatic events, which is a stressful situation that requires emergency standby at all times. The aims of this study were to examine mental health factors for each division of firefighters and to see the relationship between sleep and somatization symptoms among them. Methods : General characteristics and related inspections were conducted through self-reporting questionnaires for 1,264 firefighters working at Chungbuk fire stations. Several mental health factors were investigated by the Insomnia Severity Index, Severity of somatic symptoms, Impact of Event Scale, Perceived Stress Scale, Resilience Scale, Alcohol Dependent Screening Scale, and the Center for Epidemiologic Studies Depression Scale Depression Scale and Mini-International Neuropsychiatric Interview. Results : Among the mental health variables, the relationship between insomnia and somatization varies significantly depending on types of work. It was reported that the first aid team was significantly higher than the fire suppression and rescue team. Post-traumatic stress, depression and drinking also differ significantly depending on types of work. The first aid team reported more posttraumatic stress than the fire suppression team and more depressed mood than the rescue team. The administration part had more alcohol consumption than the fire suppression or first aid team. Resilience was significantly higher in the rescue team than the first aid team. No significant differences between the types of work about stress and suicide risks. Insomnia, stress, and post-traumatic stress were significant predictors of somatization among firefighters. Above all, insomnia was significant mental health variable affecting somatization. Conclusions : Various mental health factors were different according to the types of work in firefighters. The First aid team was more vulnerable to mental health variables such as insomnia and somatization than other divisions. Insomnia is the most important cause of somatization in firefighters, so it is recommended that they be treated for insomnia and to prepare institutional policies.

• Journal of Preventive Medicine and Public Health
• /
• v.32 no.3
• /
• pp.383-394
• /
• 1999

Objectives: This study was conducted to identify the factors influencing the mortality of Koreans over the age of 40 by a nested case-control study. Methods: The cohort consisted of the beneficiaries of Korea Medical Insurance Corporation for Government Employees & Private School Teachers and Staff(KMIC) who received health examinations of KMIC in 1992 and 1993 retrospectively. At that time, they were more than 40 years old. The cases were 19,258 cohort members who had died until December 31, 1997. The controls were 19,258 cohort members who were alive until December 31, 1997. Controls were matched with age and sex distribution of the cases. The data used in this study were the funeral expenses requesting files, and the files of health examinations and health questionnaires gathered in 1992 and 1993. To assess the putative risk factors of death, student t-test, chi-square test, multiple logistic regression analysis were used. Results : In multiple logistic regression analysis, independent risk factors of death were as follows; systolic blood pressure, diastolic blood pressure, blood glucose, AST, urine glucose, urine protein, alcohol drinking(frequency), cigarette smoking and perceived health status, intake of restoratives and blood transfusion showed positive associations with death; coffee consumption showed negative associations with death; and body mass index and serum total cholesterol showed J-shaped association with death. Conclusions: Regarding the direction of association, the result of analysis on the data restricted to '96-'97 was same as that of '93-'97. But in some variables such as obesity, serum cholesterol, the odds ratios of death in the data of '96-'97 were higer than those of '93-'94, which suggested that the data of '93-'94 was bearing effect-cause relationship. We concluded that it suggested further researches using long-term follow-up data to be needed in this area.

• Journal of Food Hygiene and Safety
• /
• v.26 no.1
• /
• pp.49-56
• /
• 2011

To investigate the toxicological effects of ${\beta}$-glucan, we performed basic studying on ${\beta}$-glucan in Sprague-Dawley (SD) rats. Standard endpoints in this study included mortality, clinical observations, changes of body weights, analysis on food consumption, ophthalmoscopic examination, hematologic examination, serum biochemistry, analysis of organ weights, gross anatomic pathology and histopathology. No clinical signs and mortality were observed in animals treated with beta-glucan throughout the experimental period. The average body weight of each treatment groups showed similar levels at end of experiment. There were no treatment-related changes in mortality, body weights changes, food consumption, ophthalmoscopic examination. Although there were statistically significant differences between the control and treated groups in some relative and absolute organ weights, and hematological and biochemical analysis, the data were in biologically normal ranges and did not show a dose-dependent manner. In the morphological change, hepatic tissue were not showed ballooning degeneration and irregular arrangement of hepatic cell in ${\beta}$-glucan treatment groups with control group. Also, organs weights (liver, heart, kidney and stomach) and hematological indices (WBC, RBC, Hb, Hct and Platelet) did not show statistically significant differences among the experimental groups. In summary of these results, there were no changes in mortality, mean body weight, clinical signs, food consumption. There were no changes in ophthalmological examination, hematology, blood chemistry, necropsy and histopathology. In conclusion, although further investigation of glucan should be performed in the functions registered in many ancient literatures, ${\beta}$-glucan is physiologically safe and may have potential as candidate food for human health.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2005.09a
• /
• pp.125-153
• /
• 2005

It has been widely known that the seismic piezo-cone penetration test (SCPTU) is one of the most useful techniques for investigating the geotechnical characteristics including dynamic soil properties. As the practical applications in Korea, SCPTU was carried out at two sites in Busan and four sites in Incheon, which are mainly composed of alluvial or marine soil deposits. From the SCPTU waveform data obtained from the testing sites, the first arrival times of shear waves were and the corresponding time differences with depth were determined using the cross-over method, and the shear wave velocity profiles (VS) were derived based on the refracted ray path method based on Snell's law and similar to the trend of cone tip resistance (qt) profiles. In Incheon area, the testing depths of SCPTU were deeper than those of conventional down-hole seismic tests. Moreover, for the application of the conventional CPTU to earthquake engineering practices, the correlations between VS and CPTU data were deduced based on the SCPTU results. For the empirical evaluation of VS for all soils together with clays and sands which are classified unambiguously in this study by the soil behavior type classification Index (IC), the authors suggested the VS-CPTU data correlations expressed as a function of four parameters, qt, fs, $\sigma$, v0 and Bq, determined by multiple statistical regression modeling. Despite the incompatible strain levels of the down-hole seismic test during SCPTU and the conventional CPTU, it is shown that the VS-CPTU data correlations for all soils clays and sands suggested in this study is applicable to the preliminary estimation of VS for the Korean deposits and is more reliable than the previous correlations proposed by other researchers.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.1 no.1
• /
• pp.21-32
• /
• 1981

Recent trends in design standards development in some European countries and U.S.A. have encouraged the use of probabilistic limit sate design concepts. Reliability based design criteria such as LSD, LRFD, PBLSD, adopted in those advanced countries have the potentials that they afford for symplifying the design process and placing it on a consistent reliability bases for various construction materials. A reliability based design criteria for RC flexural members are proposed in this study. Lind-Hasofer's invariant second-moment reliability theory is used in the derivation of an algorithmic reliability analysis method as well as an iterative determination of load and resistance factors. In addition, Cornell's Mean First-Order Second Moment Method is employed as a practical tool for the approximate reliability analysis and the derivation of design criteria. Uncertainty measures for flexural resistance and load effects are based on the Ellingwood's approach for the evaluation of uncertainties of loads and resistances. The implied relative safety levels of RC flexural members designed by the strength design provisions of the current standard code were evaluated using the second moment reliability analysis method proposed in this study. And then, resistance and load factors corresponding to the target reliability index(${\beta}=4$) which is considered to be appropriate level of reliability considering our practices are calculated by using the proposed methods. These reliability based factors were compared to those specified by our current ultimate strength design provisions. It was found that the reliability levels of flexural members designed by current code are not appropriate, and the code specified resistance and load factors were considerably different from the reliability based resistance and load factors proposed in this study.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.39 no.4
• /
• pp.227-234
• /
• 2019

This study was performed to investigate the effect of heat-stressed environment on rumen microbial diversity in Holstein cows. Rectal temperature and respiration rate were measured and rumen fluid was collected under normal environment (NE; Temperature humidity index (THI)=64.6) and heat-stressed environment (HE; THI=87.2) from 10 Holstein cows (60±17.7 months, 717±64.4 kg) fed on the basis of dairy feeding management in National Institute of Animal Science. The rumen bacteria diversity was analyzed by using the Illumina HiSeq^TM 4000 platform. The rectal temperature and respiratory rate were increased by 1.5℃ and 53 breaths/min in HE compared to that in NE, respectively. In this study, HE exposure induced significant changes of ruminal microbe. At phylum level, Fibrobacteres were increased in HE. At genus level, Ruminococcaceae bacterium P7 and YAD3003, Butyrivibrio sp. AE2032, Erysipelotrichaceae bacterium NK3D112, Bifidobacterium pseudolongum, Lachnospiraceae bacterium FE2018, XBB2008, and AC2029, Eubacterium celulosolvens, Clostridium hathewayi, and Butyrivibrio hungatei were decreased in HE, while Choristoneura murinana nucleopolyhedrovirus, Calothrix parasitica, Nostoc sp. KVJ20, Anabaena sp. ATCC 33047, Fibrobacter sp. UWB13 and sp. UWB5, Lachnospiraceae bacterium G41, and Xanthomonas arboricola were increased in HE. In conclusion, HE might have an effect to change the rumen microbial community in Holstein cows.