• Nuclear Medicine and Molecular Imaging
• /
• v.40 no.1
• /
• pp.40-47
• /
• 2006

Purpose: The aim of this study was to examine the effects of attenuation correction (AC) and scatter correction (SC) on the quantification of PET count rates. Materials and Methods: To assess the effects of AC and SC $^{18}F$-FDG PET images of phantom and cat brain were acquired using microPET R4 scanner. Thirty-minute transmission images using $^{68}Ge$ source and emission images after injection of FDG were acquired. PET images were reconstructed using 2D OSEM. AC and SC were applied. Regional count rates were measured using ROIs drawn on cerebral cortex including frontal, parietal, and latral temporal lobes and deep gray matter including head of caudate nucleus, putamen and thalamus for pre- and post-AC and SC images. The count rates were then normalized with the injected dose per body weight. To assess the effects of AC, count ratio of "deep gray matter/cerebral cortex" was calculated. To assess the effects of SC, ROIs were also drawn on the gray matter (GM) and white matter (WM), and contrast between them ((GM-WM)/GM was measured. Results: After the AC, count ratio of "deep gray matter/cerebral cortex" was increased by $17{\pm}7%$. After the SC, contrast was also increased by $12{\pm}3%$. Conclusion: Relative count of deep gray matter and contrast between gray and white matters were increased after AC and SC, suggesting that the AC would be critical for the quantitative analysis of cat brain PET data.

• Korean Journal of Environmental Agriculture
• /
• v.19 no.4
• /
• pp.358-363
• /
• 2000

This study was carried out to obtain the basic data for selecting the applicable crops in reclaimed land during desalinization period. A pot experiment was conducted with 5 different electrical conductivities of the saturated extracts $(ECe\;1,\;3,\;9,\;14,\;and\;16\;dS{\cdot}m^{-1})$ of soils taken from the Dae-Ho reclaimed tidal lands. Eight crops (Chinese cabbage, radish, tomato, red pepper, buckwheat, soybean, sesame, and green perilla) were grown for 37days. Plant height and number of leaves were surveyed on 2 and 4 weeks after seeding, and on harvest time (5 weeks). After harvest, dry weights of harvested crops were measured and soil chemical properties were analyzed. Emergence rates of crops were comparatively high except sesame. For sesame, there was no emergence at ECe over $3\;dS{\cdot}m^{-1}$. Growth and dry weight decreased significantly as increasing ECe. The ECe which decreased 50% of dry weight index were $14.2\;dS{\cdot}m^{-1}$ for radish, $11.4\;dS{\cdot}m^{-1}$ for Chinese cabbage, $10.2\;dS{\cdot}m^{-1}$ for red pepper, $8.9\;dS{\cdot}m^{-1}$ for buckwheat and green perilla, $8.6\;dS{\cdot}m^{-1}$ for soybean, and $8.9\;dS{\cdot}m^{-1}$ for tomato. At higher ECe that start the growth inhibition, increasing $1\;dS{\cdot}m^{-1}$ in ECe, 7.7, 6.5, 5.9, 5.6, 5.2, and 4.9% of dry weight decreased for buckwheat, green perilla, Chinese cabbage, radish, soybean, and tomato (red pepper), respectively. The critical value of ECe for crop survival except sesame was $15.4\;{\sim}\;23.1\;dS{\cdot}m^{-1}$.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.27 no.4
• /
• pp.398-410
• /
• 1982

Summer crops grown in uplands are greatly diversified and show a large variation in difference with year and location in Korea. The principal factor for the variation is weather, in which precipitation and temperature play a leading role and such a weather factors as wind, sun lights also influence production of the summer crops. Since artificial control of weather conditions as a main stress factor for crop production is almost impossible, it must be minimized only by an improvement of cultivation techniques and crop improvement. Precipitation plays a role as one of the most important factor for production of the summer crops and it is considered in two aspects, drought and excess moisture. This country, which belongs to monsoon territory, necessarily encounter one of this stress almost every year, even though the level is different. Therefore, the facilities for both drought and excess moisture are required, but actually it is not easy to complete for them. On this account, crops tolerant to drought, excess moisture and pests should be considered for establishing summer crops. For the districts damaged habitually every season, adequate crops should be cultured and appropriate method of planting, drainage and weed control should be applied diversely. Injuries by temperature is mainly attributed to lower temperature particularly in late fall and early spring, although higher temperature often causes some damages depending upon the kind of crops. Sometimes, lower temperature in summer season playa critical role for yield reduction in the summer crops. However, certain crops are prevented to some extent from this kind of stress by improving varieties tolerant to cold, hot weather or early maturing varieties. As is often the case, control of planting time or harvesting is able to be a good management for escaping the stress. Lodging, plant diseases and pests are considered as a direct or indirect damage due to weather stress, but these are characters able to be overcome by means of crop improvement and also controlled by other suitable methods. In addition, polytical supports capable of improving constitution of agriculture into modern industry is urgently required by programming of data for the damages, establishment of damage forecasting and compensation system.

• Economic and Environmental Geology
• /
• v.53 no.5
• /
• pp.619-629
• /
• 2020

The National Groundwater Monitoring Network (NGMN) in South Korea has been implemented in alluvial/ bedrock aquifers for efficient management of groundwater resources. In this study, aquifer types were reclassified with unconfined and confined aquifers based on water-level fluctuation and water quality characteristics. Principal component analysis (PCA) of water-level data from paired monitoring wells of alluvial/bedrock aquifers results in the principal components of both aquifers showing similar water-level fluctuation pattern. There was no significant difference in the rate of water-level rises responding to precipitations and in the NO₃-N concentrations between the alluvial and bedrock aquifers. In contrast, in the results classified with the hydrogeological type, the principal components of water level were different between unconfined and confined conditions. The water-level rises to precipitation events were estimated to be 4.6 (R²=0.8) in the unconfined and 2.1 (R²=0.4) in the confined aquifers, respectively, indicating less impact of precipitation recharge to the confined aquifer. The confined aquifers have the average NO₃-N concentration below 3 mg/L, implying the natural background level protected from the sources at surface. In summary, reclassification of aquifers into hydrogeological types clearly shows the differences between unconfined and confined aquifers in the water-level fluctuation pattern and NO₃-N concentrations. The hydrogeologic condition of aquifer could improve groundwater resource management by providing critical information on groundwater quantity through recharge estimation and quality for protection from potential contamination sources.

• Journal of Life Science
• /
• v.26 no.3
• /
• pp.376-386
• /
• 2016

Apoptosis induction has been proposed as an efficient mechanism by which malignant tumor cells can be removed following chemotherapy. The intrinsic mitochondria-dependent apoptotic pathway is frequently implicated in chemotherapy-induced tumor cell apoptosis. Since DNA-damaging agent (DDA)-induced apoptosis is mainly regulated by the tumor suppressor protein p53, and since more than half of clinical cancers possess inactive p53 mutants, microtubule-damaging agents (MDAs), of which apoptotic effect is mainly exerted via p53-independent routes, can be promising choice for cancer chemotherapy. Recently, we found that the apoptotic signaling pathway induced by MDAs (nocodazole, 17α-estradiol, or 2-methoxyestradiol) commonly proceeded through mitotic spindle defect-mediated prometaphase arrest, prolonged Cdk1 activation, and subsequent phosphorylation of Bcl-2, Mcl-1, and Bim in human acute leukemia Jurkat T cells. These microtubule damage-mediated alterations could render the cellular context susceptible to the onset of mitochondria-dependent apoptosis by triggering Bak activation, Δψm loss, and resultant caspase cascade activation. In contrast, when the MDA-induced Bak activation was inhibited by overexpression of anti-apoptotic Bcl-2 family proteins (Bcl-2 or Bcl-xL), the cells in prometaphase arrest failed to induce apoptosis, and instead underwent mitotic slippage and endoreduplication cycle, leading to formation of populations with 8N and 16N DNA content. These data indicate that cellular apoptogenic mechanism is critical for preventing polyploid formation following MDA treatment. Since the formation of polyploid cells, which are genetically unstable, may cause acquisition of therapy resistance and disease relapse, there is a growing interest in developing new combination chemotherapies to prevent polyploidization in tumors after MDA treatment.

• Journal of Life Science
• /
• v.24 no.5
• /
• pp.505-514
• /
• 2014

To examine the anti-obese activity of miscellaneous cereal grains, 80% ethanol extracts from eight selected miscellaneous cereal grains were compared for their cytotoxic effects on 3T3-L1 murine preadipocytes. The ethanol extract of proso millet exhibited the highest cytotoxicity. Further fractionation of the ethanol extract with methylene chloride, ethyl acetate, and n-butanol showed that the cytotoxicity of the ethanol extract was mainly partitioned into the butanol fraction. As compared with differentiated mature adipocytes, 3T3-L1 preadipocytes were more susceptible to the cyctotoxicity of the butanol fraction. When each organic solvent fraction (25 ${\mu}g/ml$) was added during the differentiation period for 6 days, the cell viability was not affected significantly except for the butanol fraction, but the intracellular lipid accumulation declined to a level of 81.5%~50.3% of the control. The Oil Red O staining data also demonstrated that the ethanol extract as well as the butanol fraction could inhibit the differentiation of 3T3-L1 preadipocytes into mature adipocytes. The presence of the butanol extract during the induced adipocytic differentiation also resulted in a significant reduction in the expression levels of critical adipogenesis mediators $(C/EBP{\alpha}$, $PPAR{\gamma}$, aP2, and LPL) to a barely detectable or undetectable level and the cells retained the fibroblast-like morphology of 3T3-L1. In 3T3-L1 cells, the cytotoxicity of the butanol fraction (50-100 ${\mu}g/ml$) was accompanied by mitochondrial membrane potential (${\Delta}{\psi}m$) loss, caspase-3 activation, and PARP degradation. Taken together, these results indicate that proso millet grains possess pro-apoptotic and anti-adipocytic activities toward adipocytes, which can be applicable to prevention of obesity.

• Korean Journal of Food Science and Technology
• /
• v.37 no.3
• /
• pp.484-491
• /
• 2005

Quantitative microbial risk assessment (QMRA) analyzes potential hazard of microorganisms on public health and offers structured approach to assess risks associated with microorganisms in foods. This paper addresses specific risk management questions associated with Staphylococcus aureus in kimbab and improvement and dissemination of QMRA methodology, QMRA model was developed by constructing four nodes from retail to table pathway. Predictive microbial growth model and survey data were combined with probabilistic modeling to simulate levels of S. aureus in kimbab at time of consumption, Due to lack of dose-response models, final level of S. aureus in kimbeb was used as proxy for potential hazard level, based on which possibility of contamination over this level and consumption level of S. aureus through kimbab were estimated as 30.7% and 3.67 log cfu/g, respectively. Regression sensitivity results showed time-temperature during storage at selling was the most significant factor. These results suggested temperature control under $10^{\circ}C$ was critical control point for kimbab production to prevent growth of S. aureus and showed QMRA was useful for evaluation of factors influencing potential risk and could be applied directly to risk management.

• Women's Health Nursing
• /
• v.2 no.1
• /
• pp.53-67
• /
• 1996

A total health state evaluation of Korean female elderlies was made by using the questionary scheme measuring the physical, mental and social functions of the elderlies, in order to investigate the critical factors for the health maintenance of female elderlies and to develop their preventive nursing program. A total of 280 subjects over 65 years old living in Seoul and the suburban area were selected and interviewed during the period of September and October in 1995. The materials collected were analyzed statistically by using SAS data processing program, and the results and recommendations are summarized as follows. 1. The physical health state of Korean elderly women was evaluated to be satisfactory by showing an average score of 3.722 in 5.0 full-score scale. But this score was lower than those evaluated for the elderlies combined both sexes(4.054). The mental health state of the subjects was also evaluated as high scoring 3.484, possibly due to the fact that 78% of the subjects lived together with their children's family. On the other hand, the social health state of the subjects was relatively low scoring 2.585, mainly due to that 80% of them was widows which was resulted by the 6-7 years longer life-expectancy of Korean women. 2. A significant differences in the physical health state scores between different age groups was observed, indicating the rapid ageing process occurring in this age group. The family structure was appeared to be an important factor influencing the physical health state of the female elderlies ; the physical health score of the women with her husband only was higher than that of those living with children's families, and the lowest score was obtained from those living alone. 3. The age was the most important factor determining the mental health state of the subjects, while the religion, educational status, marriage state and family structure did not significantly influenced the mental health state of the aged women. 4. The social health state of the subject was deeply influenced by the marriage state and family structure, showing significantly lower scores with widowers compared to the married couples. Those living with their married spouse only obtained the highest social health score, while those living along showed the lowest score. The parent and grandparentship of those living with their children and the religion, especially Catholic and Protestant, had positive influence on the social health state of the aged women. 5. The mental health state of aged women showed significant correlation with the factors determining the physical health, except for digestive system related ability and sexual ability and the highest extra home ability. 6. The mental health state of aged women showed significant correlation with the factors determining social health, especially with the parent and grandparentship and the family relative's role. From these results, the following recommendations are made. 1. Since the physical, mental and social health states of aged people are deeply influenced by the sex and the average values of the both sex can create misleading figures, the health evaluation of the elderlies should be made separately by sex. 2. Since the health state of aged women is highly influenced by their family structure, the spouse's role and living with married couple only should be emphasized in respect of preventive health care. 3. The social activity programs and grandparentship teaching programs should be prepared in the nursing care program for aged people.

• Journal of Chest Surgery
• /
• v.35 no.1
• /
• pp.20-26
• /
• 2002

Background: Due to the concern of flow competition or retrograde steal, it has been generally suggested that the right gastroepiploic artery(RGEA) pedicled graft should be used in critical coronary stenosis lesion. The study was designed to evaluate the potential of retrograde flow competition in the RGEA pedicled graft by measuring the native pressure differences(PD) between the normal coronary artery and celiac arterial pressure, which would be compared with trans-stenosis pressure gradients(TSPG) in coronary artery occlusive disease. Material and Method: Between July, 1998 and February, 1999, pressures of the right coronary artery and the right gastroepiploic artery(or the celiac artery) were measured in patients with the patent right coronary artery(n=12). The PD between the arteries was compared with the TSPG in the occlusive coronary arteries(n=32). Result: The pressures of the normal right coronary artery and celiac artery were 143$\pm$23 vs. 134$\pm$17mmHg in systole(p<0.005), 74$\pm$13 vs. 73$\pm$14mmHg in diastole(p=NS), and 100$\pm$16 vs. 97$\pm$15mmHg in mean (p<0.05). The PD between the arteries were -8~25mmHg in systole, -4~7mmHg in diastole, and -1~10mmHg in mean. The TSPG measured in the occlusive coronary arteries were -4~19(7$\pm$5.8)mmHg in the lesion less than 75% stenosis vs. 7~74(27$\pm$18.3)mmHg in the 75% or over stenosis lesion(p<0.005). The normally existing pressure difference between the coronary arteries and RGEA(15~20mmHg) was significantlyless than the TSPG in .the occlusive coronary artery with 75% or over stenosis(p<0.001). Conclusion: If the pressure gradient between the RGEA and the coronary artery distal to the stenosis is the main determinant of development of retrograde flow competiton in the RGEA pedicled graft, the above data suggests that there will be little chance of competition when It is used in the coronary lesion with 75% or over stenosis.

• Asia pacific journal of information systems
• /
• v.17 no.4
• /
• pp.61-95
• /
• 2007

Small-and-medium sized enterprises(SMEs) represent quite a large proportion of the industry as a whole in terms of the number of enterprises or employees. However researches on information system so far have focused on large companies, probably because SMEs were not so active in introducing information systems as larger enterprises. SMEs are now increasingly bringing in information systems such as ERP(Enterprise Resource Planning Systems) and some of the companies already entered the stage of ongoing use. Accordingly, researches should deal with the use of information systems by SME s operating under different conditions from large companies. This study examined factors and mechanism inducing faithful appropriation of information systems, in particular integrative systems such as ERP, in view of individuals` active feedback-seeking behavior. There are three factors expected to affect end users` feedback-seeking behavior for faithful appropriation of information systems. They are management support, peer IT champ support, and IT staff support. The main focus of the study is on how these factors affect feedback-seeking behavior and whether the feedback-seeking behavior plays the role of mediator for realizing faithful appropriation of information systems by end users. To examine the research model and the hypotheses, this study employed an empirical method based on a field survey. The survey used measurements mostly employed and verified by previous researches, while some of the measurements had gone through minor modifications for the purpose of the study. The survey respondents are individual employees of SMEs that have been using ERP for one year or longer. To prevent common method bias, Task-Technology Fit items used as the control variable were made to be answered by different respondents. In total, 127 pairs of valid questionnaires were collected and used for the analysis. The PLS(Partial Least Squares) approach to structural equation modeling(PLS-Graph v.3.0) was used as our data analysis strategy because of its ability to model both formative and reflective latent constructs under small-and medium-size samples. The analysis shows Reliability, Construct Validity and Discriminant Validity are appropriate. The path analysis results are as follows; first, the more there is peer IT champ support, the more the end user is likely to show feedback-seeking behavior(path-coefficient=0.230, t=2.28, p<0.05). In other words, if colleagues proficient in information system use recognize the importance of their help, pass on what they have found to be an effective way of using the system or correct others' misuse, ordinary end users will be able to seek feedback on the faithfulness of their appropriation of information system without hesitation, because they know the convenience of getting help. Second, management support encourages ordinary end users to seek more feedback(path-coefficient=0.271, t=3.06, p<0.01) by affecting the end users' perceived value of feedback(path-coefficient=0.401, t=6.01, p<0.01). Management support is far more influential than other factors that when the management of an SME well understands the benefit of ERP, promotes its faithful appropriation and pays attention to employees' satisfaction with the system, employees will make deliberate efforts for faithful appropriation of the system. However, the third factor, IT staff support was found not to be conducive to feedback-seeking behavior from end users(path-coefficient=0.174, t=1.83). This is partly attributable to the fundamental reason that there is little support for end users from IT staff in SMEs. Even when IT staff provides support, end users may find it less important than that from coworkers more familiar with the end users' job. Meanwhile, the more end users seek feedback and attempt to find ways of faithful appropriation of information systems, the more likely the users will be able to deploy the system according to the purpose the system was originally meant for(path-coefficient=0.35, t=2.88, p<0.01). Finally, the mediation effect analysis confirmed the mediation effect of feedback-seeking behavior. By confirming the mediation effect of feedback-seeking behavior, this study draws attention to the importance of feedback-seeking behavior that has long been overlooked in research about information system use. This study also explores the factors that promote feedback-seeking behavior which in result could affect end user`s faithful appropriation of information systems. In addition, this study provides insight about which inducements or resources SMEs should offer to promote individual users' feedback-seeking behavior when formal and sufficient support from IT staff or an outside information system provider is hardly expected. As the study results show, under the business environment of SMEs, help from skilled colleagues and the management plays a critical role. Therefore, SMEs should seriously consider how to utilize skilled peer information system users, while the management should pay keen attention to end users and support them to make the most of information systems.