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Distribution of hazardous heavy metals in commercial herbal medicines classified by plant parts used in seoul (서울지역 유통한약재의 약용부위에 따른 유해중금속 분포)

  • Kim, Donggyu;Kim, Bogsoon;Han, Eunjung;Han, Changho;Kim, Oukhee;Choi, Byunghyun;Hwang, Insook;Chae, Youngzoo;Kim, Minyoung;Park, Seungkook
    • Analytical Science and Technology
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    • v.22 no.6
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    • pp.504-513
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    • 2009
  • In this study, the safety of commercial herbal medicines was evaluated by determining concentration of hazardous heavy metals. 3,152 samples (244 types) purchased by individual packing unit from market in Seoul, were analyzed using ICP-MS and mercury analyzer. As a result, the content (mg $kg^{-1}$) of Pb was higher in the above-ground part (0.92) than underground part (0.43). But in case of As and Cd contents, there is slightly higher in the underground-parts (0.26, 0.13) than the above-ground parts (0.18, 0.08). There were many herbal medicines exceeding regulatory limits of Cd comparing with other metals. The levels of Hg seemed to be different between above-ground part(0.009) and underground part (0.008) but there was no sample exceeding tolerance limits. In the comparison of imported samples with domestic herbal medicines, it was shown that Pb, As, and Hg were measured highly in the imported ones, Cd was not significantly different (t-test, p<0.05). The significant correlation was observed between Pb and As (r=0.386, p<0.01) but there was no difference in other parts. The heavy metal contamination of herbal medicines measured in total amount of respective heavy metals (mg $kg^{-1}$) was high in Flos (6.241) and Caulis (2.238), and decreased in the order of Cortex (1.634), Herba (1.154), Perithecium (0.861), Rhizoma (0.828), Radix (0.825), Fructus (0.475), and was low in Semen (0.422) (ANOVA-test, p<0.05).

Concurrent Validity of the Self-Report and Proxy-Report Versions of a Health-Related Quality of Life Measure: A Focus Group Study (초등학교 아동과 보호자에게 적용한 삶의 질 평가도구의 동시타당도 연구: 표적집단 파일럿연구)

  • Choi, Bongsam
    • The Journal of Korean Academy of Sensory Integration
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    • v.21 no.2
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    • pp.45-57
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    • 2023
  • Objective : The purpose of this study was to investigate the concurrent validity of the self- and proxy-report versions of the KIDSCREEN-10 quality of life questionnaire. Methods : A total of nine children and nine parents were selected to represent a cohort registered for a school-based wellness program. Two versions of the KIDSCREEN-10 questionnaire (self- and proxy reports) were administered to the children and their parents. The Rasch rating scale model was applied to determine the dimensionality and item difficulty of the two versions of the questionnaire. Moreover, the item-person matching map and Spearman's rho were compared to confirm the concurrent validity of the two versions. Results : All items, except four items (i.e., autonomy, home life, concentration/learning, and peers/social support), fit the Rasch rating scale model of the children's self-report version of the questionnaire. With regard to the parent's proxy-report version, two items misfit the model. While the items of the self- and proxy-report versions showed similar item difficulties, the parents had a tendency to be more severe in their ratings than the children. The correlation between the two versions was relatively low (Spearman's rho = .533, p > .05). The scatterplots between the two versions showed differences in the item difficulties of the physical and psychological well-being and self-perception items. Conclusion : These findings suggest that the three identified items should be taken into consideration when measuring children's health-related quality of life using the KIDSCREEN-10 questionnaire.

Influence of Spring Warming in the Arctic-East Asia Region on the Arctic Oscillation and Dust Days in Korea Attributed to Dust Storms (북극-동아시아 지역의 봄철 온난화가 북극 진동-한국의 황사 사례일의 종관 기상에 미치는 영향 분석)

  • Ji-Sun Kim;Jae-Hee Cho;Hak-Sung Kim
    • Journal of the Korean earth science society
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    • v.45 no.2
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    • pp.121-135
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    • 2024
  • This study examined the influence of near-surface atmospheric warming in the Arctic-East Asia region during spring (March-May) from 1991 to 2020 on the synoptic-scale meteorology of dust storm-induced dust days in Seoul, Korea, in response to the Arctic Oscillation. Increased springtime warming in the Arctic-East Asia region correlated with a reduction of six days in the occurrence of dust storm-induced dust days in Seoul, Korea, along with a decline in the intensity of these days by -1.6 ㎍ m-3yr-1 in PM10 mass concentration. The declining number of dust storm-induced dust days in Korea during the 2010s was the result of synoptic-scale meteorological analysis, which showed increased high-pressure activity as indicated by the negative potential vorticity unit. Moreover, a distinct pattern emerged in the distribution of dust storm-induced dust days in Korea based on the Arctic Oscillation Index (AOI), showing an increase in negative AOI and a decrease in positive AOI. Although the northward shift of the polar jet weakened the southerly low-pressure system activity over Mongolia and northern China, a reinforced high-pressure system formed over the Chinese continent during dust-storm-induced dust days with a negative AOI. This resulted in both a decrease in the frequency of dust-storm-induced dust days and reduction in wind speeds, facilitating their transport from source regions to Korea. Conversely, on days with positive AOIs, an extensive warm and stagnant high-pressure system dominated mainland China, accompanied by further cooling of the northern segment of the polar jet. A notable decline in wind speed in the lower troposphere across the Mongolia-northern China-Korea region diminished the occurrence of dust storm-induced dust days and also weakened their long-range transport.

Characteristics of Leuconostoc spp. isolated from radish kimchi and its immune enhancement effect (무김치에서 분리한 Leuconostoc 속의 특성과 면역증강 효과)

  • Seoyeon Kwak;Seongeui Yoo;Jieon Park;Woosoo Jeong;Hee-Min Gwon;Soo-Hwan Yeo;So-Young Kim
    • Food Science and Preservation
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    • v.30 no.6
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    • pp.1082-1094
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    • 2023
  • The purpose of this study was to examine the characteristics of Leuconostoc spp. isolated from radish kimchi and to investigate the potential for the use of functional ingredients by evaluating enzymatic characteristics, safety, and immune-enhancing effects among the isolates, including Lactobacillus rhamnosus ATCC53103 (LGG) as a control strain. All test strains exhibited β-glucosidase enzyme activity that releases β-1,4 sugar chain bonds. In addition, as a result of antibiotic resistance assay among the isolates, MIC values on 8 antibiotics were below compared to the EFSA standard, and hemolytic experiments confirmed that all showed gamma hemolysis without hemolytic ability. As a result of the antibacterial activity experiment, the Leu. mesenteroides K2-4 strain showed a higher activity than LGG against Bacillus cereus and Staphylococcus aureus. Additionally, the activity of the NF-kB/AP-1 transcription factor increased when the isolates were treated in macrophage RAW cells. These results were related to increasing the high mRNA expression levels on TNF-α and IL-6 by Leu. mesenteroides K2-4 strain to be treated at low concentration. Consequently, we suggest that it will be useful as a candidate for functional food ingredients.

Analysis of the Reduction Effect of Combined Treatment with UV-C and Organic Acid to Reduce Aspergillus ochraceus and Rhodotorula mucilaginosa Contamination (Aspergillus ochraceus와 Rhodotorula mucilaginosa 저감을 위한 자외선과 유기산 복합처리 효과 분석)

  • Eun-Seon Lee;Jong-Hui Kim;Bu-Min Kim;Mi-Hwa Oh
    • Journal of Food Hygiene and Safety
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    • v.39 no.1
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    • pp.54-60
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    • 2024
  • This study investigated the effectiveness of using pathogens and aqueous acids to reduce the Aspergillus ochraceus and Rhodotorula mucilaginosa contamination in livestock production environments. For this study, 1 mL of each bacterial suspension (107-108 spores/mL) was inoculated on a knife surface, dried at 37℃, and used under each treatment condition. First, to investigate the effect of organic acids, acetic, lactic, and citric acids were used. Subsequently, to select the appropriate concentration, they were prepared at concentrations of 0.5, 1, 2, 3, 4, and 5%, respectively. Accordingly, to further maximize the effect of organic acid treatment, we combined the treatment with ultraviolet light. The two strains showed a significant difference (P<0.05) compared to the initial strain, with a greater than 90% decrease in the concentrations of all organic acids. Consequently, acetic and lactic acids decreased by approximately 5 and 2 log colony forming unit (CFU)/cm2, respectively, when treated with ultraviolet light (360 mJ/cm2); however, citric acid decreased by less than 1 log CFU/cm2. However, when manufactured with 4% acetic acid, a severe malodor was emitted, making it difficult for workers to use it in a production environment. Accordingly, the optimal treatment conditions for organic acid and ultraviolet light for application were selected as follows: immersion in a 4% lactic acid solution for 1 minute and then, sterilization with ultraviolet light at 360 mJ/cm2. Finally, when a pork meat sample was cut with a knife that was finally washed with lactic acid and treated with ultraviolet light, the low level of inoculum transferred from the cleaned knife to the surface of the sample was not detected. In conclusion, using this established method can prevent cross-contamination of the surface of the meat during processing.

Purification of antigenic proteins of Paragonimus westermani and their applicability to experimental cat paragonimiasis (폐(肺)디스토마(Paragonimus westermani) 감염(感染) 고양이 혈청(血淸)에 대(對)한 ELISA 항체가(抗體價)의 의의(意義))

  • Choi, Won-Young;Yoo, Jae-Eul;Nam, Ho-Woo;Choi, Hyung-Rak
    • Parasites, Hosts and Diseases
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    • v.24 no.2
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    • pp.177-186
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    • 1986
  • This study was designed to evaluate the partially purified antigens which were fractionated from crude extract of Paragonimus westermani and to monitor the enzyme-linked immunosorbent assay (ELISA) in experimental cat paragonimiasis during the course of infection as well as before and after chemotherapy. Crude extract of 6-month-old adult P. westermani was fractionated to 5 antigens by successive applications of ammonium sulfate precipitation, ion exchange chromatography and gel filtration. And the cats, 10 in each group, were infected with 60, 30, 15, and 5 metacercariae, then the half of each group was treated with praziquantel 2 times in one day of 100mg per kilogram of weight on 150 days after the infection. Sera were collected every 10 days. ELISA was performed with the concentration of $2{\mu}g/ml$ antigen, 100 times diluted sera and 1,000 times diluted alkaline phosphatase conjugated anti-cat IgG. The results were as follows: 1. Absorbance by ELISA with proteins precipitated by differential concentration of ammonium sulfate was the highest at $51{\sim}65%$ precipitate (PA2), followed by $0{\sim}50%$ precipitate (PAl), $66{\sim}80%$ precipitate (PA3), and $81{\sim}90%$ precipitate (PA4). Unprecipitated protein over 90% ammonium sulfate (PA5) showed the lowest antigenicity. 2. Fractionation of PA1, PA2, and PA3 through the DEAE-cellulose column did not differentiate the antigenic proteins. 3. By passing through the Sephadex G-200 column, PA1 and PA2 were fractionated to high molecular weight proteins and those of low molecular weight which showed high absorbance by ELISA (PA1-I, II and PA2-I, II). But PA3 was shown to have a fraction of high molecular weight proteins (PA3-I) which showed high antigenicity. 4. SDS-polyacrylamide gel electrophoresis of PA1-I, P A1-II, PA2-I, PA2-II, PA3-I, and crude extract was performed. Fraction PA1-I was composed of proteins which had the molecular weight of 270 kilodaltons(KD) to 196 KD; of them 220KD protein was major band. Fraction PA2-I was composed of $255{\sim}225\;KD$, and PA3-I, $255{\sim}240\;KD$, respectively. Fraction PA1-II and fraction PA2-II consisted of 30 KD proteins. 5. Absorbance by ELISA began to increase within $10{\sim}20$ days after the infection and reached the highest on $140{\sim}180$ days, then made plateau thereafter. 6. Absorbance by ELISA decreased after praziquantel treatment. In 60 metacercariae infection group, the absorbance had been decreasing, but remained within the positive range during observation period, while those of 30, 15, and 5 metacercariae infection groups turned to negative range. 7. Fraction PA1-II showed the highest antigenicity in ELISA, then fraction PA2-I, fraction PA1-I, fraction PA2-II, fraction PA3-I and crude extract followed. In early phase of infection, the absorbance of fraction PA1-II showed more rapid increase than those of the other fractions and it came to positive range at $20{\sim}30$ days after infection.

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Effects of Total Mixed Fermentation Feeds Based on Rice-straw and Six Forage Crops on the Productivity of Holstein Cows (청예사료작물과 볏짚 위주의 완전배합발효사료 급여가 Holstein 착유우의 생산성에 미치는 영향)

  • Lee, H. J.;Kim, H. S.;Ki, K. S.;Jeong, H. Y.;Baek, K. S.;Kim, J. S.;Cho, K. K.;Cho, J. S.;Lee, H. G.;Woo, J. H.;Choi, Y. J.
    • Journal of Animal Science and Technology
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    • v.45 no.1
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    • pp.69-78
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    • 2003
  • This experiment was carried out to evaluate the value of total mixed fermentation feeds(TMFF) as completely mixed ration and to observe the effect of various kinds of TMFF on the palatability, feed intake, and milk performance in Holstein cows. The dry matter (DM) content of TMFF used in the experiment was 23.98-28.42% range, and CP, TDN, ADF and NDF were 16.2${\sim}$19.2%, 58.3-65.1%, 34.4-39.6% and 46.9${\sim}$49.9% levels, respectively. The relative feed value (RFV) in rape-, alfalfa-, grass-, oat-, corn-TMFF groups were 138.6, 133.9, 116.5, 111.8, 111.4 and 108.1, respectively. Among these groups, RFV of rye-TMFF group was lowest. Dry matter disappearance(DMD) showed 0.8${\sim}$.9% to the all kinds of TMFF groups. The pH was 3.89${\sim}$.87 and $NH_3$-N concentration was 6.93-8.66 mg/$d\ell$. The acetic acid concentration in the raw material of TMFF showed low level of 0.19${\sim}$0.57%, lactic acid showed high level of 1.17${\sim}$3.21% and butyric acid was very high as 0.03${\sim}$0.32%. Therefore, these results provide evidence that the quality of TMFF was not so bad. In the daily fresh matter intake on the alfalfa-, grass-, rape-, corn-, oats- and rye-TMFF were showed 62.85, 60.48, 58.04, 57.11, 54.61 and 45.74 kg respectively. All TMFF showed high palatability as daily dry matter intake of 1.95 to 2.90% by body weight of experimental cows. Body condition score(BCS) was gradually increased in during 60 days of the experiment term. Average daily gain(ADG) showed about 140.0${\sim}$326.7g. In alfalfa-TMFF group, the ADG was higher than in the other groups (p<0.05). Also, the increase in BCS was observed in grass-TMFF group (3.07 to 3.34) and rye-TMFF group was decreased in 3.07 to 3.34 (p<0.05). The milk yield appropriately showed a range of 16.16${\sim}$18.95 kg in all groups. Among these groups, alfalfa-TMFF group was highest(P<0.05). Average milk fat contents showed high levels of 4.06${\sim}$4.79% and the level was high in order of rape-, grass-, corn-, alfalfa-, rye- and oats-TMFF. Milk protein was highest in forage-TMFF and level of lactose in milk was approximately 4.56% in overall groups. Solid non fat(SNF) and total solid(TS) contents were 8.75% and 12.8%, respectively. However, milk composition was not significantly affected by TMFF.

Comparison of Single-Breath and Intra-Breath Method in Measuring Diffusing Capacity for Carbon Monoxide of the Lung (일산화탄소 폐확산능검사에서 단회호흡법과 호흡내검사법의 비교)

  • Lee, Jae-Ho;Chung, Hee-Soon;Shim, Young-Soo
    • Tuberculosis and Respiratory Diseases
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    • v.42 no.4
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    • pp.555-568
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    • 1995
  • Background: It is most physiologic to measure the diffusing capacity of the lung by using oxygen, but it is so difficult to measure partial pressure of oxygen in the capillary blood of the lung that in clinical practice it is measured by using carbon monoxide, and single-breath diffusing capacity method is used most widely. However, since the process of withholding the breath for 10 seconds after inspiration to the total lung capacity is very hard to practice for patients who suffer from cough, dyspnea, etc, the intra-breath lung diffusing capacity method which requires a single exhalation of low-flow rate without such process was devised. In this study, we want to know whether or not there is any significant difference in the diffusing capacity of the lung measured by the single-breath and intra-breath methods, and if any, which factors have any influence. Methods: We chose randomly 73 persons without regarding specific disease, and after conducting 3 times the flow-volume curve test, we selected forced vital capacity(FVC), percent of predicted forced vital capacity, forced expiratory volume within 1 second($FEV_1$), percent of forced expiratory volume within 1 second, the ratio of forced expiratory volume within 1 second against forced vital capacity($FEV_1$/FVC) in test which the sum of FVC and $FEV_1$ is biggest. We measured the diffusing capacity of the lung 3 times in each of the single-breath and intra-breath methods at intervals of 5 minutes, and we evaluated which factors have any influence on the difference of the diffusing capacity of the lung between two methods[the mean values(ml/min/mmHg) of difference between two diffusing capacity measured by two methods] by means of the linear regression method, and obtained the following results: Results: 1) Intra-test reproducibility in the single-breath and intra-breath methods was excellent. 2) There was in general a good correlation between the diffusing capacity of the lung measured by a single-breath method and that measured by the intra-breath method, but there was a significant difference between values measured by both methods($1.01{\pm}0.35ml/min/mmHg$, p<0.01) 3) The difference between the diffusing capacity of the lung measured by both methods was not correlated to FVC, but was correlated to $FEV_1$, percent of $FEV_1$, $FEV_1$/FVC and the gradient of methane concentration which is an indicator of distribution of ventilation, and it was found as a result of the multiple regression test, that the effect of $FEV_1$/FVC was most strong(r=-0.4725, p<0.01) 4) In a graphic view of the difference of diffusing capacity measured by single-breath and intra-breath method and $FEV_1$/FVC, it was found that the former was divided into two groups in section where $FEV_1$/FVC is 50~60%, and that there was no significant difference between two methods in the section where $FEV_1$/FVC is equal or more than 60% ($0.05{\pm}0.24ml/min/mmHg$, p>0.1), but there was significant difference in the section, less than 60%($-4.5{\pm}0.34ml/min/mmHg$, p<0.01). 5. The diffusing capacity of the lung measured by the single-breath and intra-breath method was the same in value($24.3{\pm}0.68ml/min/mmHg$) within the normal range(2%/L) of the methane gas gradient, and there was no difference depending on the measuring method, but if the methane concentration gradients exceed 2%/L, the diffusing capacity of the lung measured by single-breath method became $15.0{\pm}0.44ml/min/mmHg$, and that measured by intra-breath method, $11.9{\pm}0.51ml/min/mmHg$, and there was a significant difference between them(p<0.01). Conclusion: Therefore, in case where $FEV_1$/FVC was less than 60%, the diffusing capacity of the lung measured by intra-breath method represented significantly lower value than that by single-breath method, and it was presumed to be caused largely by a defect of ventilation-distribution, but the possibility could not be excluded that the diffusing capacity of the lung might be overestimated in the single-breath method, or the actual reduction of the diffusing capacity of the lung appeared more sensitively in the intra-breath method.

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Studies on Neck Blast Infection of Rice Plant (벼 이삭목도열병(病)의 감염(感染)에 관(關)한 연구(硏究))

  • Kim, Hong Gi;Park, Jong Seong
    • Korean Journal of Agricultural Science
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    • v.12 no.2
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    • pp.206-241
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    • 1985
  • Attempts to search infection period, infection speed in the tissue of neck blast of rice plant, location of inoculum source and effects of several conditions about the leaf sheath of rice plants for neck blast incidence have been made. 1. The most infectious period for neck blast incidence was the booting stage just before heading date, and most of necks have been infected during the booting stage and on heading date. But $Indica{\times}Japonica$ hybrid varieties had shown always high possibility for infection after booting stage. 2. Incubation period for neck blast of rice plants under natural conditions had rather a long period ranging from 10 to 22 days. Under artificial inoculation condition incubation period in the young panicle was shorter than in the old panicle. Panicles that emerged from the sheath of flag leaf had long incubation period, with a low infection rate and they also shown slow infection speed in the tissue. 3. Considering the incubation period of neck blast of rice plant, we assumed that the most effective application periods of chemicals are 5-10 days for immediate effective chemicals and 10-15 days for slow effective chemicals before heading. 4. Infiltration of conidia into the leaf sheath of rice plant carried out by saturation effect with water through the suture of the upper three leaves. The number of conidia observed in the leaf sheath during the booting stage were higher than those in the leaf sheath during other stages. Ligule had protected to infiltrate of conidia into the leaf sheath. 5. When conidia were infiltrated into the leaf sheath, the highest number of attached conidia was observed on the panicle base and panicle axis with hairs and degenerated panicle, which seemed to promote the infection of neck blast. 6. The lowest spore concentration for neck blast incidence was variable with rice varietal groups. $Indica{\times}Japonica$ hybrid varieties were infected easily compared to the Japonica type varieties, especially. The number of spores for neck blast incidence in $Indica{\times}Japonica$ hybrid varieties was less than 100 and disease index was higher also in $Indica{\times}Japonica$ hybrid than in Japonica type varieties. 7. Nitrogen content and silicate content were related with blast incidence in necks of rice plants in the different growing stage changed during growing period. Nitrogen content increased from booting stage to heading date and then decreased gradually as time passes. Silicate content increased from booting stage after heading with time. Change of these content promoted to increase neck blast infection. 8. Conidia moved to rice plant by ascending and desending dispersal and then attached on the rice plant. Conidia transfered horizontally was found very negligible. So we presumed that infection rate of neck blast was very low after emergence of panicle base from the leaf sheath. Also ascending air current by temperature difference between upper and lower side of rice plant seemed to increase the liberation of spores. 9. Conidial number of the blast fungus collected just before and after heading date was closely related with neck blast incidence. Lesions on three leaves from the top were closely related with neck blast incidence, because they had high potential for conidia formation of rice blast fungus and they were direct inoculum sources for neck blast. 10. The condition inside the leaf sheath was very favorable for the incidence of neck blast and the neck blast incidence in the leaf sheath increased as the level of fertilizer applied increased. Therefore, the infection rate of neck blast on the all panicle parts such as panicle base, panicle branches, spikelets, nodes, and internodes inside the leaf sheath didn't show differences due to varietal resistance or fertilizers applied. 11. Except for others among dominant species of fungi in the leaf sheath, only Gerlachia oryzae appeared to promote incidence of neck blast. It was assumed that days for heading of varieties were related with neck blast incidence.

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The Evaluation of Difference according to Image Scan Duration in PET Scan using Short Half-Lived Radionuclide (단 반감기 핵종을 이용한 PET 검사 시 영상 획득 시간에 따른 정량성 평가)

  • Hong, Gun-Chul;Cha, Eun-Sun;Kwak, In-Suk;Lee, Hyuk;Park, Hoon;Choi, Choon-Ki;Seok, Jae-Dong
    • The Korean Journal of Nuclear Medicine Technology
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    • v.16 no.1
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    • pp.102-107
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    • 2012
  • Purpose : Because of the rapid physical decay of the short half-lived radionuclide, counting of event for image is very limited. In this reason, long scan duration is applied for more accurate quantitative analysis in the relatively low sensitive examination. The aim of this study was to evaluate the difference according to scan duration and investigate the resonable scan duration using the radionuclide of 11C and 18F in PET scan. Materials and Methods : 1994-NEMA Phantom was filled with 11C of $30.08{\pm}4.22MBq$ and 18F of $40.08{\pm}8.29MBq$ diluted with distilled water. Dynamic images were acquired 20frames/1minute and static image was acquired for 20minutes with 11C. And dynamic images were acquired 20frames/2.5minutes and static image was acquired for 50minutes with 18F. All of data were applied with same reconstruction method and time decay correction. Region of interest (ROI) was set on the image, maximum radioactivity concentration (maxRC, kBq/mL) was compared. We compared maxRC with acquired dynamic image which was summed one bye one to increase the total scan duration. Results : maxRC over time of 11C was $3.85{\pm}0.45{\sim}5.15{\pm}0.50kBq/mL$ in dynamic image, and static image was $2.15{\pm}0.26kBq/mL$. In case of 18F, the maxRC was $9.09{\pm}0.42{\sim}9.48{\pm}0.31kBq/mL$ in dynamic image and $7.24{\pm}0.14kBq/mL$ in static. In summed image of 11C, as total scan duration was increased to 5, 10, 15, 20minutes, the maxRC were $2.47{\pm}0.4$, $2.22{\pm}0.37$, $2.08{\pm}0.42$, $1.95{\pm}0.55kBq/mL$ respectively. In case of 18F, the total scan duration was increased to 12.5, 25, 37.5, and 50minutes, the maxRC were $7.89{\pm}0.27$, $7.61{\pm}0.23$, $7.36{\pm}0.21$, $7.31{\pm}0.23kBq/mL$. Conclusion : As elapsed time was increased after completion of injection, the maxRC was increased by 33% and 4% in dynamic study of 11C and 18F respectively. Also the total scan duration was increased, the maxRC was reduced by 50% and 20% in summed image of 11C and 18F respectively. The percentage difference of each result is more larger in study using relatively shorter half-lived radionuclide. It appears that the accuracy of decay correction declined not only increment of scan duration but also increment of elapsed time from a starting point of acquisition. In study using 18F, there was no big difference so it's not necessary to consider error of quantitative evaluation according to elapsed time. It's recommended to apply additional decay correction method considering decay correction the error concerning elapsed time or to set the scan duration of static image less than 5minutes corresponding 25% of half life in study using shorter half-lived radionuclide as 11C.

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