• 한국의학물리학회지:의학물리
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• 제31권3호
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• pp.71-80
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• 2020

This paper provides a brief review of the advanced technologies for carbon ion radiotherapy (CIRT), with a focus on current developments. Compared to photon beam therapy, treatment using heavy ions, especially a carbon beam, has potential advantages due to its physical and biological properties. Carbon ion beams with high linear energy transfer demonstrate high relative biological effectiveness in cell killing, particularly at the Bragg peak. With these unique properties, CIRT allows for accurate targeting and dose escalation for tumors with better sparing of adjacent normal tissues. Recently, the available CIRT technologies included fast pencil beam scanning, superconducting rotating gantry, respiratory motion management, and accurate beam modeling for the treatment planning system. These techniques provide precise treatment, operational efficiency, and patient comfort. Currently, there are 12 CIRT facilities worldwide; with technological improvements, they continue to grow in number. Ongoing technological developments include the use of multiple ion beams, effective beam delivery, accurate biological modeling, and downsizing the facility.

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.1003-1010
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• 2005

A study consisting of 3 trials was designed to assess the relative biological efficacy of DL-methionine (DL-Met) in comparison to liquid methionine hydroxy analogue (MHA-FA) in growing pigs. In trial I a basal diet was supplemented with three graded levels of DL-methionine (0.25, 0.50 and 0.75 g/kg) or liquid MHA-FA (0.0285, 0.0570 and 0.0855 g/kg) on equimolar basis. The basal diet contained 18.3% CP, 0.22% Met and 0.51% Met+Cys, which is below the methionine requirement for weaned pigs between 10 and 20 kg BW according to NRC (1998) but adequate in all other essential nutrients and energy. Using an exponential model, the efficacy of the two methionine sources was estimated from nitrogen retention data obtained in 42 piglets with an initial BW between 11.0 kg (Exp. 1) and 11.7 kg (Exp. 2). In trials II and III, with a total of 192 and 96 pigs, and with an initial BW of 10.6 and 21 kg, respectively, growth response criteria were assessed to determine if in agreement with previous studies in pigs and poultry a biological effectiveness of about 65% on average could be confirmed for liquid MHA-FA in comparison to DL-met. Based on N-retention (trial I) the biological efficacy of liquid MHA-FA on a weight-to-weight basis was calculated to be 62% relative to DL-met. Basically, these results were confirmed using growth response criteria as measures; the results of trial II and III revealed no significant differences in growth performance and feed conversion between treatments indicating that 100 parts of liquid MHA-FA can be replaced by 65 parts of DL-met.

• Journal of the Korean Data and Information Science Society
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• 제17권4호
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• pp.1349-1364
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• 2006

An analytic approach that provides explicit estimates of risk on cataract and epilation data is evaluated by reasonableness of conceivable relative risk models regarding a simple, odds, logistic or Gompertz regression method, assuming a binomial distribution. In these analyses, we apply relative risk models with two thresholds between epilators and nonepilators from a highly characteristic lesion of which radiation cataract does not occur around 2 gray for a single acute exposure. The risk models are fitted to the data assuming 10 as a constant relative biological effectiveness of neutron. The likelihood of observing the entire data set in these models fitted is evaluated by an individual binary-response array. Estimation of a threshold with or without severe epilation and the 100 ($1-\alpha$)% confidence limits are derived from the maximum likelihood approach. The relative risk model with two thresholds can be expressed as a formula with structure of Background $\times$ RR, where RR includes threshold models with or without epilation. The radiosensitivity of ionizing radiation to cataracts has been examined for the relationship between epilators and nonepilators.

• 한국환경성돌연변이발암원학회지
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• 제7권2호
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• pp.103-111
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• 1987

The effects of LET (linear energy transfer) of radiation on the induction of somatic chromosome mutations or gene mutations of Drosophila melanogaster were studied. For detecting somatic chromosome mutations and gene mutations, Drosophila wing spot system and eye-color spot system were used, respectively. The frequencies of somatic chromosome mutations or gene mutations induced after third instar larval treatment with 23 MeV neutrons, thermal neutrons, X-rays were examined. From these data, the RBE(relative biological effectiveness) values of 23 MeV neutrons relative to X-rays for induction of somatic chromosome mutations or gene mutations were calculated. The present results suggest that high LET radiations are efficient than X-ray in producing not only somatic chromosome mutations but also gene mutations.

• Journal of Korean Biological Nursing Science
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• 제1권1호
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• pp.71-85
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• 1999

The purpose of this study was to determine the effect of periodic low-intensity exercise during hindlimb suspension on the mass, relative weight, myofibrillar protein content in soleus, plantaris and gastrocnemius muscles. To examine the effectiveness of periodic low-intensity exercise on mass, and myofibrillar protein content of hindlimb muscles, adult female Wistar rats were suspended(HS) and half of these rats walked on a treadmill for 45min/day(15 min every 4h) at 5m/min and a $15^{\circ}$ grade(HS-EX). Soleus wet weight was 33.51% significantly smaller(p<0.005) and relative soleus weight of hindlimb suspended rats was 31.96% smaller(p<0.005) compared with those of control rats following seven days of hindlimb suspension. Plantaris wet weight was 7.5% smaller(p<0.01) and relative plantaris weight was 11.83% smaller(p<0.05) compared with those of control rats following seven days of hindlimb suspension. Gastrocnemius wet weight was 11.31% significantly smaller(p<0.005) and relative gastrocnemius weight was 17.13% significantly smaller(p<0.005) compared with those of control rats following seven days of hindlimb suspension. Soleus wet weight while increased by relative soleus weight increased by 25.13%, 27.59% each through periodic low intensity exercise during hindlimb suspension(p<0.05, p<0.05). Plantaris wet weight and relative plantaris weight increased by 1.04%, 10.98%(p<0.05) each, and gastrocnemius wet weight and relative gastrocnemius weight increased by 1.98%, 12.02%(p<0.05) each through periodic low intensity exercise during hindlimb suspension. Wet weight of soleus, plantaris and gastrocnemius in HS-EX rats did not recover to control level. Myofibrillar protein content of soleus, plantaris and gastrocnemius was 48.24%, 40.85% and 37.33% significantly smaller(p<0.005) respectively compared with those of control rats following seven days of hindlimb suspension. Myofibrillar protein content of soleus, plantaris and gastrocnemius increased by 40.68%, 25.07% and 17.93%(p<0.005) each through periodic low intensity exercise during hindlimb suspension. Myofibrillar protein content of soleus, plantaris, and gastrocnemius in HS-EX rats did not recover to control level. The results suggest that periodic low intensity exercise can attenuate hindlimb muscle atrophy induced by hindlimb suspension.

• Radiation Oncology Journal
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• 제11권1호
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• pp.35-42
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• 1993

원자력 시설 이용 증대에 따른 불의의 방사선 사고에 대비하여 방사선 작업종사자의 피폭시 진단을 위한 검사방법이 필요하다. 이 방법은 검사를 위한 검체의 채취가 용이하고, 짧은 시간내에 간편하게 많은 Sample을 처리하여야 한다는 조건을 만족시켜야 한다. 인체의 다양한 조직 및 세포 중에서 위의 조건을 만족시킬 수 있는 말초 혈액의 림파구는 비교적 방사선에 대한 감수성이 높다고 알려져 있으며, 채집 또한 용이하여 생물학적 선량 측정의 도구로써 이용가치가 높아 방사선 작업 종자사나 피폭 가능성이 있는 사람의 screening test에 사용될수 있다. 정상인에 있어서의 림파구내 미세핵 존재 여부와 방사선 피폭량에 따른 미세핵 발생빈도를 시험관내 실험을 통하여 표준화시켜 향후 방사선 피폭시 피폭선량을 역으로 산출해 낼 수 있는 방사선 장해의 평가 기술 개발의 기초자료를 마련하기 위하여 본 실험을 시행하였다. 정상인으로 부터 혈액을 채취하여 림파구만을 Ficoll-Hypaque gradient 방법으로 추출하여 배양한 다음, 본 치료방사선과의 중성자 치료기 (MC-50, scanditronix)와 Co-60 teletherapy unit(Theratron-780, AECL)를 이용하여 방사선 조사를 시행하였다. Cytokinesis-block method를 이용하여 첫번째 분열을 한 림파구에서 미세핵(Micronucleus)을 현미경을 통하여 계수한 다음, 이의 선량-반응 관계식을 linear-quadratic model을 사용하여 구하고, 이를 근거로 하여 gamma-ray에 대한 중성자의 Relative biological effectiveness (RBE)를 산출하였다. 방사선에 피폭되지 않은 림파구의 미세핵 발생빈도는 binucieated cell한 개당 $0.013{\pm}0.0002$로써 사람에 따라 통계학적으로 큰 차이를 보이지 않았다. 그림 2와 3에서 보는 바와 같이 개개인으로부터 얻은 data는 감마선과 중성자선 모두에서 선량-반응 곡선의 linear-quadratic equation에 잘 일치하였다. 감마선과 중성자선 모두에서 선량에 따른 미세핵의 발생빈도는 선량이 높을수록 비례하여 증가하였는데, 감마선의 경우에는 $r^2=1.000,\;x^2=0.7074$, p=0.95였으며, 중성자선인 경우에는 $r^2=0.996,\;x^2=7.6834$, p=0.11 였다. 이를 linear-quadratic model로 분석하면, 가장 적합한 선은 감마선인 경우에는 y= ($0.31{\pm}0.049)\;D+(0.0022{\pm}0.0002)\;D^2+(13.19{\pm}1.854$) 였으며, 중성자선인 경우에는 y=($0.99{\pm}0.528)\;D+(0.0093{\pm}0.0047)\;D^2+(13.31{\pm}7.309$) 였었다. 감마선에 대한 중성자선의 상대적 생물학적 효과비 (RBE)는 y=aD+$bD^2$+c를 다음과 같은 식으로 변형시켜 계산하였다. $$\frac{[-a{pm}\sqrt{a^2-4b\;(c-y}}]}{2{\times}6}$$ 미세핵 발생빈도가 세포당 0.05와 0.8사이에서의 중성자선의 상대적 생물학적 효과비는 $2.37{\pm}0.17$ 이었다. 이상의 결과를 종합하여 볼 때 선량에 따른 미세핵 발생빈도는 기존의 방사선 감수성 test의 결과와 대동소이하여, 앞으로 방사선 감수성을 측정하는 방법으로 이용할 수 있으며, 또한 실험방법이 비교적 간단하며 짧은 시간에 결과를 도출할 수 있어 생물학적 선량측정 도구로써 널리 이용될 수 있을 것으로 생각되어 진다.

• 대한방사선치료학회지
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• 제35권
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• pp.33-39
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• 2023

목 적: 환자 체표면과 고정기구 사이에 발생하는 공기층 두께에 따른 선량 변화를 치료 계획을 통해 알아보고자 한다. 대상 및 방법: 팬텀과 열가소성 고정기구 사이에 5 mm 두께의 Bolus를 0, 1, 2, 3장을 놓아 공기층의 두께를 조절하였고 고정기구를 씌워 총 4가지 조건으로 전산화 모의단층촬영을 시행하였다. 430 cGy (Relative Biological Effectiveness,RBE)씩 6번이 조사 되도록 계획하였으며, 임상표적체적의 95% 부피에 전달된 선량이 2580 cGy (RBE)가 되도록 치료 계획을 수립하였다. 임상표적체적의 선량은 Lateral dose profile의 반치폭값으로 평가하였고 피부 선량은 선량 체적 곡선으로 평가하였다. 결 과: 임상표적체적에서 Lateral dose profile 반치폭 값은 4.89, 4.86, 5.10, 5.10 cm로 나타났다. 피부에서 4가지 조건의 선량의 평균값은 D_95%3.25±1.7 cGy (RBE), D_30%1193.5±10.2 cGy (RBE)의 차이를 보였으며 처방 선량 1%에서의 피부 부피 값 평균은 83.22±4.8% 이내의 차이를 확인하였다. 공기층 두께 변화에 따른 임상표적체적과 피부에서의 선량 모두 큰 변화를 보이지는 않았다. 결론 : 탄소입자 치료를 위해 Solid 형태의 고정기구 제작 시 약간의 공기층은 CTV의 선량 적용 범위를 벗어나지 않는다.

• 농업과학연구
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• 제47권4호
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• pp.903-920
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• 2020

Since its first demonstration as a practical genome editing tool in the early 2010s, the use of clustered regularly interspaced short palindromic repeat (CRISPR) along with the endonuclease Cas9 (CRISPR/Cas9) has become an essential choice for generating targeted mutations. Due to its relative simplicity and cost-effectiveness compared to other molecular scissors, i.e., zinc finger nuclease (ZFN) and transcription activator-like effector nuclease (TALEN), the CRISPR/Cas9 system has been shown to have a massive influence on genetic studies regardless of the biological kingdom. Although the system is in the process of being established, numerous protocols have already been released for the system and there have been various topics of CRISPR related papers published each year in ever-increasing manner. Here, we will briefly introduce CRISPR/Cas9 system and discuss the variants of the CRISPR system. Also, their applications to crop improvement will be dealt with mainly ornamental crops among horticultural crops other than Arabidopsis as a model plant. Finally, some issues on the barriers restraining the use of CRISPR system on floricultural crops, the prospect of CRISPR system as a DNA-free genome editing tool with efficient facilitators and finally, the future perspectives on the CRISPR system will be described.

• Asian-Australasian Journal of Animal Sciences
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• 제21권10호
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• pp.1506-1515
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• 2008

Two feeding trials were conducted to assess the relative bioavailability (RBV) of methionine hydroxy analogue calcium salt (MHA-Ca) in comparison to DL-methionine (DL-Met). Male Ross 308 (1-38 days) and Cobb 500 chickens (1-42 days) were used in studies 1 and 2, respectively. Experimental diets based on wheat and soybean meal or sorghum and soybean meal were fed during three phases. In both experiments graded levels of DL-Met and MHA-Ca were supplemented to Met+Cys deficient basal diets. Additionally, in experiment 1, increasing levels of a DL-Met preparation diluted with corn starch to 65% purity (DL-Met65) were supplemented. Birds were kept in floor pens and feed and water were available ad libitum. Body weights and feed consumption were recorded at the beginning and end of the experimental periods and weight gain and feed efficacy were computed subsequently. At the end of the experiments, a number of birds were slaughtered for carcass evaluation (dressing percentage, breast meat yield). Dose response data were analysed by both ANOVA and nonlinear common plateau asymptotic regression. In both experiments birds responded significantly to increasing levels of either methionine source. However, RBV of MHA-Ca compared to DL-Met was markedly (in many cases significantly) below 84%, the value which would have been expected from MHA-Ca's chemical characteristics. Excluding some extremely low RBV figures of trial 2, RBV of MHA-Ca averaged to about 63% in relation to DL-Met. In addition, supplementation of DL-Met65 allowed confirmation of nonlinear common plateau asymptotic regression to be suitable to determine RBV.

• Journal of Periodontal and Implant Science
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• 제47권5호
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• pp.273-291
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• 2017

Purpose: Although static magnetic fields (SMFs) have been used in dental prostheses and osseointegrated implants, their biological effects on osteoblastic and cementoblastic differentiation in cells involved in periodontal regeneration remain unknown. This study was undertaken to investigate the effects of SMFs (15 mT) on the osteoblastic and cementoblastic differentiation of human osteoblasts, periodontal ligament cells (PDLCs), and cementoblasts, and to explore the possible mechanisms underlying these effects. Methods: Differentiation was evaluated by measuring alkaline phosphatase (ALP) activity, mineralized nodule formation based on Alizarin red staining, calcium content, and the expression of marker mRNAs assessed by reverse transcription polymerase chain reaction (RT-PCR). Signaling pathways were analyzed by western blotting and immunocytochemistry. Results: The activities of the early marker ALP and the late markers matrix mineralization and calcium content, as well as osteoblast- and cementoblast-specific gene expression in osteoblasts, PDLCs, and cementoblasts were enhanced. SMFs upregulated the expression of Wnt proteins, and increased the phosphorylation of glycogen synthase $kinase-3{\beta}$ ($GSK-3{\beta}$) and total ${\beta}-catenin$ protein expression. Furthermore, p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK), and nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) pathways were activated. Conclusions: SMF treatment enhanced osteoblastic and/or cementoblastic differentiation in osteoblasts, cementoblasts, and PDLCs. These findings provide a molecular basis for the beneficial osteogenic and/or cementogenic effect of SMFs, which could have potential in stimulating bone or cementum formation during bone regeneration and in patients with periodontal disease.