• Bulletin of the Korean Chemical Society
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• 제30권10호
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• pp.2309-2317
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• 2009

Depurination, the release of purine bases from nucleic acids by hydrolysis of the N-glycosidic bond, gives rise to alterations of the cell genome. Though cells have evolved mechanisms to repair these lesions, unrepaired apurinic sites have been shown to have two biological consequences: lethality and base substitution errors. 2-Bromopropane (2-BP) is used as an intermediate in the synthesis of pharmaceuticals, dyes, and other organics. In addition, 2-BP has been used as a replacement for chloroflurocarbons and 1,1,1-trichloroethane as a cleaning solvent in electronics industry. However, 2-BP was found to cause reproductive and hematopoietic disorders in local workers exposed to it. Owing to the toxicity of 2-BP, there has been a tendency to use 1-BP as an alternative cleaning solvent to 2-BP. However, 1-BP has also been reported to be neurotoxic in rats. Though $N^7$-guanine adduct of 2-BP has been reported previously, massive depurination of the nucleosides and calf thymus DNA was observed in this study. We incubated the nucleosides (ddG, dG, guanosine, ddA, dA and adenosine) with excess amount 2-BP at the physiological condition (pH 7.4, $37\;{^{\circ}C}$), which were analyzed by HPLC and LC-MS/MS. In addition, the time and dose response relationship of depurination in nucleosides induced by 2-bromopropane at the physiological condition was investigated. Similarly, incubation of calf-thymus DNA with the excess amount 2-BP at the physiological condition was also performed. In addition, the time and dose response relationship of depurination in calf-thymus DNA induced by 2-BP at the physiological condition was investigated. Those results suggest that the toxic effect of 2-BP could be both from the depurination of nucleosides and DNA adduct formation.

• Advances in environmental research
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• 제3권3호
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• pp.231-251
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• 2014

The present study examines the phosphate adsorption potential and behavior of mixture of Ground Burnt Patties (GBP), a solid waste generated from cooking fuel used in earthen stoves and Red Soil (RS), a natural substance in fixed bed column mode operation. The characterization of adsorbent was done by Proton Induced X-ray Emission (PIXE), and Proton Induced ${\gamma}$-ray Emission (PIGE) methods. The FTIR spectroscopy of spent adsorbent reveals the presence of absorbance peak at $1127cm^{-1}$ which appears due to P = O stretching, thus confirming phosphate adsorption. The effects of bed height (10, 15 and 20 cm), flow rate (2.5, 5 and 7.5 mL/min) and initial phosphate concentration (5 and 15 mg/L) on breakthrough curves were explored. Both the breakthrough and exhaustion time increased with increase in bed depth, decrease in flow rate and influent concentration. Thomas model, Yoon-Nelson model and Modified Dose Response model were used to fit the column adsorption data using nonlinear regression analysis while Bed Depth Service Time model followed linear regression analysis under different experimental condition to evaluate model parameters that are useful in scale up of the process. The values of correlation coefficient ($R^2$) and the Sum of Square Error (SSE) revealed the Modified Dose Response model as the best fitted model to the experimental data. The adsorbent mixture responded effectively to the desorption and reusability experiment. The results of this finding advocated that mixture of GBP and RS can be used as a low cost, highly efficient adsorbent for phosphate removal from aqueous solution.

• Archives of Pharmacal Research
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• 제15권2호
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• pp.169-175
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• 1992

Anti-inflammatory glucocorticoid (GC) derivatives have been clinically used in immune-malfunctional diseases for their immunosuppressive activity. However, there is still a lack of knowledge on the relationship between anti-inflammatory and immunosuppressive activities. In order to compare immunosuppressive activities with the known anti-inflammatory activities of the GC derivatives, eight clinically used GC derivatives including hydrocortisone, prednislone, 6$\alpha$-methyl prednisolone, triamcinolone, dexamethasone, betamethasone, triamcinolone acetonide and fluocinolone acetonide were selected, and lymphoblastosis inhibition and plaque-forming cell (PFC) response in mice were studied as immunological parameters. In Con A-induced lymphoblatosis inhibition invitro, all derivatives showed potent inhibition $IC_{50}$ values of the derivaties except methyl prednisolone and triamcinolone were less than $10^{-7}$M and good dose dependency was obtained. This result was well correlated with that of their anti-inflammatory potencies obtained. This result was well correlated with that of their anti-inflammatory potencies and their receptor binding affinities. However, in PFC response, consistent result were not obtained. Total numbers of PFCs per spleen were decreased by some derivatives, but numbers of PFCs per $10^6$ cells were not decreased by systemic administration of but numbers of PFCs per $10^6$ cells were not decreased by systemic administration of GC at the dose of 0.05 mg/mouse. Furthermore, at the dose of 0.1 mg/mouse, numbers of PFCs per $10^6$ cells were found to be increased, although total PFCs per spleen were decreased.

• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.533-538
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• 2018

As the use of digital radiographic system has been expanded, there are some concerns an increase about in patient of radiation dose. Therefore, International Electro-technical Commission (IEC) has been proposed a standard foe exposure index (EI). In this study, the EI was measured on human chest model using computed radiography (CR). Radiation quality used RQA5 of IEC62494-1. After acquiring the chest anterior posterior image (Chest AP) by using the phantom, the EI was obtained by applying the system response. In this study, we have analyzed the images with the detector size (Full filed ROI) and the optimized image (Fit filed ROI). The EI increased proportionally with radiation dose increase. Due to the discrete increase in pixel value, the EI showed an exponential increase. The discrete increase in noise equivalent quanta (NEQ) resulted in a discrete increase in the EI. The EI of the two images used in this study increased with increasing NEQ but showed different increments. For the measurement of the EI, IEC standards must be followed. The EI should be used as an index to evaluate the image quality for quality control of X-ray image rather than as an indicator of exposure dose. When calculating the EI, the system response should be applied depending on whether or not the grid is used. The size of the field should be obtained by including only the necessary parts.

• Asian-Australasian Journal of Animal Sciences
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• 제32권2호
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• pp.274-281
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• 2019

Objective: The objective of this study was to estimate the risk of Campylobacter jejuni (C. jejuni) infection from various jerky products in Korea. Methods: For the exposure assessment, the prevalence and predictive models of C. jejuni in the jerky and the temperature and time of the distribution and storage were investigated. In addition, the consumption amounts and frequencies of the products were also investigated. The data for C. jejuni for the prevalence, distribution temperature, distribution time, consumption amount, and consumption frequency were fitted with the @RISK fitting program to obtain appropriate probabilistic distributions. Subsequently, the dose-response models for Campylobacter were researched in the literature. Eventually, the distributions, predictive model, and dose-response model were used to make a simulation model with @RISK to estimate the risk of C. jejuni foodborne illness from the intake of jerky. Results: Among 275 jerky samples, there were no C. jejuni positive samples, and thus, the initial contamination level was statistically predicted with the RiskUniform distribution [RiskUniform (-2, 0.48)]. To describe the changes in the C. jejuni cell counts during distribution and storage, the developed predictive models with the Weibull model (primary model) and polynomial model (secondary model) were utilized. The appropriate probabilistic distribution was the BetaGeneral distribution, and it showed that the average jerky consumption was 51.83 g/d with a frequency of 0.61%. The developed simulation model from this data series and the dose-response model (Beta Poisson model) showed that the risk of C. jejuni foodborne illness per day per person from jerky consumption was $1.56{\times}10^{-12}$. Conclusion: This result suggests that the risk of C. jejuni in jerky could be considered low in Korea.

• Nutrition Research and Practice
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• 제15권1호
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• pp.80-94
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• 2021

BACKGROUND/OBJECTIVES: Recent studies have reported chocolate consumption has beneficial effects on blood pressure, obesity, and dyslipidemia, which are components of metabolic syndrome (MetS). However, evidence regarding these relationships in Asia is limited. The aim of this study was to investigate relations between chocolate consumption and MetS in Korea. SUBJECTS/METHODS: Study subjects were 6,982 adults aged 19-64 years free of major chronic diseases that participated in the 2014-2016 Korea National Health and Nutrition Examination Survey. Information on chocolate consumption was obtained using food frequency questionnaires. For primary analysis, subjects were divided into two groups: non-consumer (n = 3,741, 53.6%); consumer (n = 3,241, 46.4%). In order to investigate dose-response effects on MetS, chocolate consumers were divided into quartiles based on amounts consumed: Q1 (n = 789, 24.3%); Q2 (n = 837, 25.8%); Q3 (n = 863, 26.6%); Q4 (n = 752, 23.2%) in second analysis. RESULTS: Chocolate consumers; 1) were more physically active(P < 0.0001); 2) less likely to smoke(P < 0.0001); 3) paid more attention to food nutrition labels (P < 0.0001), and 4) had healthier dietary patterns, that is, they consumed vegetables, fruits, and dairy products more frequently(P < 0.0001) than non-consumers. Furthermore, chocolate consumers had a 30% lower risk of MetS (odds ratio, 0.70; 95% confidence interval, 0.58-0.86; P = 0.0005). However, dose-response effects between chocolate intake and MetS was not found by secondary analysis after excluding non-consumers. CONCLUSIONS: In conclusion, chocolate consumers had healthier lifestyles and dietary patterns and a lower prevalence of MetS than non-consumers, as determined by our primary analysis. Although dose-response effects were not found to be significant among chocolate consumers during secondary analysis, the patterns were partially similar. This cross-sectional finding shows chocolate consumption does not increase the risk of MetS. The prospective studies and intervention trials in Korea are needed to confirm this cross-sectional finding.

• Journal of Preventive Medicine and Public Health
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• 제26권2호
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• pp.251-267
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• 1993

연폭로의 정도와 자각증상과의 관계를 알아보기 위하여 435명의 연폭로 남자 근로자와 212명의 일반 사무직 남자 근로자를 대상으로 연폭로 지표가 되는 혈중 연, 혈중 Zinc Protoporphyrin(ZPP), 요중 Delta-aminolevulinic acid(DALA), 혈색소, 혈구 용적 측정을 위한 혈액 시료 및 소변 시료를 채취하여 분석하였고, 연관련 자각증상 조사는 14개의 증상 조사 항목을(표 3 및 별첨 1) 피검자가 응답 하도록하여 상담 의사의 면접을 통한 확인을 거쳐 수집 하였다. 수집된 각 항목은 인체 조직계 증상군별로 1) 위장관계 증상 2) 신경과 근육 및 관절계 증상 3) 일반 체질적 증상 4) 정신과적 증상으로 구분하여 연폭로 지표 수준과 연폭로 작업 여부에 따른 자각증상 호소율을 비교 조사하여 얻은 결론은 다음과 같다. 1. 연폭로군에서 대조군보다 유의하게 높은 자각증상 호소율을 보인 증상군은 신경과 근육 및 관절계 증상으로 "손이나 발이 저리거나 쥐가 잘난다", "관절이 아프거나 쑤신다", "손가락, 손, 발 등에 힘이 없다", "근육통을 느낀다" 순 이었다. 2. 연폭로군과 대조군의 자각증상 호소율에 가장 큰 차이를 보인 증상 항목은 "손이나 발이 저리거나 쥐가 잘 난다"였으며, 전체 조사 대상에서 가장 높은 증상 호소율을 보인 증상 항목은 일반 체질적 자각 증상군의 "전보다 피곤감을 느낀다"였다. 3. 전체 조사 대상의 혈중 연과 혈중 ZPP 수준에 따른 연폭로량의 증가와 자각증상 호소율의 증가를 보인 증상 항목은 신경과 근육 및 관절계 증상군의 "손이나 발이 저리거나 쥐가 잘난다", "관절이 아프거나 쑤신다", "손가락. 손 발 등에 힘이 없다", "근육통을 느낀다"와 위장관계 증상군의 "아랫배가 아파서 고생한 적이 있다"였다. 4 연폭로군에서 혈중 연과 혈중 ZPP 수준에 따른 연폭로량의 증가와 자각증상 호소율의 증가를 보인 증상 항목은 신경과 근육 및 관절계 증상으로 혈중 연의 증가에 따라 증상 호소율이 증가하였다. 5. 연폭로군에서 39세 이하 와 40세 이상 연령군으로 나누어 비교시 39세 이하 군의 증상 호소율이 40세 이상 군보다 높게 나왔으며. 신경과 근육 및 관절계 증상이 39세이하 군에서 혈중 연의 증가와 함께, 40세 이상 군에서 혈중 ZPP의 증가와 함께 자각증상 호소율의 증가를 나타냈다. 6. 연폭로 지표에 따른 폭로수준과 증상 호소율과의 관계를 알아보기 위하여 대조군에 대한 폭로군, 연폭로군의 저농도 폭로군에 대한 고농도 폭로군의 교차비를 산출한 결과 신경과 근육 및 관절계 증상군의 "손이나 발이 저리거나 쥐가 잘난다", "관절이 아프거나 쑤신다", "손가락, 손, 발 등에 힘이 없다", "근육통을 느낀다"와 위장관계 증상군의 "아랫배가 아파서 고생한 적이 있다"가 연폭로량의 증가에 따른 교차비의 증가를 보여 양-반응의 관계를 추정할 수 있었다.

• 대한두경부종양학회지
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• 제15권1호
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• pp.22-28
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• 1999

Purpose: We performed this study retrospectively to evaluate local control, survival, prognostic factors, and failure patterns in patients with non-Hodgkin's lymphoma of Waldeyer's ring. Materials and Methods: From April 1984 to November 1996,41 patients with non-Hodgkin's lymphoma of Waldeyer's ring were treated with combined chemotherapy and radiation therapy. Age was ranged from 19 to 73 years old with a median age of 55 years, and there were 26 male and 15 female patients. Primary site was tonsil in 26 and base of the tongue in 7 and nasopharynx in 8, and stage distribution showed stage I in 12 and stage II in 29 patients. Pathologic classification was done according to Working Formulation. There were 1 with follicular mixed small cleaved and large cell, 8 with diffuse small cleaved cell, 7 with diffuse mixed small and large cell, and 25 cases with diffuse large cell. All patients were treated with combination of chemotherapy and radiation therapy. Chemotherapy regimen consisted of either CHOP-Bleo(cyclophosphamide, adriamycin, vincristine, prednisolone, bleomycin) or COP-BLAM III(cyclophosphamide, vincristine, prednisolone, bleomycin, adriamycin, procarbazine). Radiation dose ranged from 3600cGy to 6620cGy with a median dose of 5040cGy. Follow-up time was ranged from 15 months to 159 months(median 55 months). Results: The complete response was achieved in 98%(40/41) and partial response in 2%(1/41). The complete response rate were the followings: 66.7% for stage I and 51.7% for stage II after chemotherapy, 100% for stage I and 96.6% for stage II after overall treatment respectively. The overall survival rate and disease-tree survival rates at 5 years were 82.6% and 79.5%, respectively. Prognostic factors for overall survival were age(p=0.007), stage(p=0.03), nodal status(p=0.006) and radiation dose(p=0.003). The factors associated with disease-tree survival were stage(p=0.04), nodal status(p=0.004) and radiation dose(p=0.009). The failure patterns were analized in evaluable 35 patients with complete response. Locoregional failure was noted in 2 patients and distant metastasis in 5 patients. Conclusion: Our results suggest that combined modality therapy is the appropriate treatment for stage I-II intermediate grade non-hodgkin's lymphoma of the Waldeyer's ring. However, our material is small and the analysis is retrospective. Randomized prospective studies for combined therapy, radiation therapy alone and chemotherapy alone are needed.

• Journal of Radiation Protection and Research
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• 제24권3호
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• pp.143-154
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• 1999

Panasonic UD-809P 알비도 중성자 열형광선량계를 팬텀에 장착시켜 원자력발전소에서 중성자 개인선량당량을 측정하였다. 측정된 판독값으로부터 Panasonic 사의 사용자 매뉴얼에 제시되어 있는 방법을 이용하여 열중성자와 초열중성자 및 속중성자로 인한 개인선량당량을 평가하였다. 그 결과 열중성자 성분의 비율이 높은 원자력발전소에서는 속중성자로 인한 개인선량당량을 적절하게 평가할 수 없는 것으로 확인되었는데, 이는 열중성자로 인한 알비도 성분이 열형광선량계로 재입사 되는 양이 이론적인 값과 상당한 차이가 나기 때문인 것으로 추정되었다. 따라서 원자력발전소와 같이 열중성자 성분의 비율이 높은 조건에서 속중성자로 인한 중성자 개인선량당량을 평가하기 위하여 중성자 성분을 열중성자와 속중성자로 구분한 새로운 중성자 선량계산 알고리즘을 제안하였으며, 각각의 성분에 대한 개인선량당량과 교정인자, 민감도 인자 평가공식을 유도하였다.

• 한국의학물리학회지:의학물리
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• 제31권4호
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• pp.135-144
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• 2020

Purpose: Gafchromic films for proton dosimetry are dependent on linear energy transfers (LETs), resulting in dose underestimation for high LETs. Despite efforts to resolve this problem for single-energy beams, there remains a need to do so for multi-energy beams. Here, a bimolecular reaction model was applied to correct the under-response of spread-out Bragg peaks (SOBPs). Methods: For depth-dose measurements, a Gafchromic EBT3 film was positioned in water perpendicular to the ground. The gantry was rotated at 15° to avoid disturbances in the beam path. A set of films was exposed to a uniformly scanned 112-MeV pristine proton beam with six different dose intensities, ranging from 0.373 to 4.865 Gy, at a 2-cm depth. Another set of films was irradiated with SOBPs with maximum energies of 110, 150, and 190 MeV having modulation widths of 5.39, 4.27, and 5.34 cm, respectively. The correction function was obtained using 150.8-MeV SOBP data. The LET of the SOBP was then analytically calculated. Finally, the model was validated for a uniform cubic dose distribution and compared with multilayered ionization chamber data. Results: The dose error in the plateau region was within 4% when normalized with the maximum dose. The discrepancy of the range was <1 mm for all measured energies. The highest errors occurred at 70 MeV owing to the steep gradient with the narrowest Bragg peak. Conclusions: With bimolecular model-based correction, an EBT3 film can be used to accurately verify the depth dose of scanned proton beams and could potentially be used to evaluate the depth-dose distribution for patient plans.