• Journal of Radiation Industry
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• v.4 no.3
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• pp.209-213
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• 2010

Bacterial blight is one of the most serious diseases of rice (Oryza sativa L.), and it has been known that Xanthomonas oryzae pv. oryzae (Xoo) causes this disease symptom. To develop resistance rice cultivars against Xoo, 3,000 lines of $M_3$ mutants, which were irradiated with gamma ray, were tested by 'scissor-dip method' primarily, and 191 putative resistant lines were selected. In $M_4$ generation, these lines were screened again with various ways such as measuring of symptom of bacterial blight in leaf, number of tiller, fresh weight, and phenotypic segregation ratio in next generation. Finally, six resistance lines were selected. RT-PCR analysis revealed that these lines displayed high level of R-genes such as Xa21, Pi36, and Pi-ta. These results indicate that mutations by gamma ray cause disruptions of regulatory signal transduction systems of these R-genes. Furthermore, these selected mutants could be useful for the development of rice cultivar resistant to Xoo.

• Journal of Korean Academy of Oral Health
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• v.42 no.4
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• pp.224-228
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• 2018

Objectives: As a first step to study the anticaries effect of ethanol alone, we investigated the effects of ethanol on the expression levels of the atpB gene and proton permeability of Streptococcus mutans in suspension cultures. Methods: S. mutans UA159 was grown in brain heart infusion medium at either pH 4.8 or 6.8. The total extracted RNA was reverse-transcribed into cDNA using a $Superscript^{TM}$ First-Strand Synthesis System. The resulting cDNA and negative controls were amplified by ABI PRISM 7700 real-time PCR system with SYBR Green PCR Master Mix. For proton flux assay, bacterial suspensions were titrated to pH 4.6 with 0.5 M HCl, and then additional 0.5 M HCl was added to decrease the pH values by approximately 0.4 units. The subsequent increase in pH was monitored using a glass electrode. Ten percent (v/v) butanol was added to the suspensions at 80 min to disrupt the cell membrane. Results: In a concentration-dependent manner, ethanol alone not only decreased the growth rate of S. mutans and the expression of the atpB gene but also increased the proton permeability at both pH 4.8 and 6.8. Conclusions: These findings suggest that ethanol has the potential for an anticaries ingredient. We believe that ethanol may be used together with fluoride and/or other cariostatic agents in order to develop better anticaries toothpastes and/or mouthrinses.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.502-502
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• 2023

지난 140여년(1880~2022)간 지구의 연평균 기온은 약 1.5℃ 상승하였다. 이에 따라 폭염, 홍수, 가뭄 등 이상기후 발생이 급증하고 있으며, 생태계가 급격히 변화하여 담수호의 산소량 또한 급속히 감소하고 있다. 소양호는 총길이 60 km, 유역면적 2.703 km², 최대저수량 29억톤으로, 유역면적은 북한강 유역의 25%에 달하며 북한강 상류에 위치하고 있는 국내 최대의 인공호이다. 따라서 소양호 유역의 관리는 북한강 유역의 수질 관리와 수도권 수자원 공급의 핵심 중 하나라고 볼 수 있다. 그러나 기후변화에 따라 소양호의 성층현상에도 변동이 생겼을 것으로 판단되고 있다. 호소의 성층현상은 수심에 따른 온도의 변화로 발생하는 현상으로, 성층현상이 심하면 유체는 연직운동이 제한되고 상대적으로 수평방향 운동이 활발해진다. 소양호는 수심이 매우 깊으며, 열용량이 크기 때문에 여름에 성층이 형성되는 온대일순환호(warm monomictic lake)로 분리된다. 성층현상이 심하면 호소 하부의 저층에서는 용존산소가 거의 없어 혐기성 상태가 되고, 침전된 유기물이 혐기성 미생물에 의해 분해되기 때문에 수질은 크게 악화된다. 따라서 본 연구는 30년간의 소양호의 수온과 DO의 변동을 분석하여 성층현상의 변동성을 파악하고자 하였다. 이에 따라 약 30년간(1993년 1월~2022년 12월) 0~90 m까지 측정한 수온, DO 데이터를 이용하였다. 데이터는 매달 최소 1회~최대 5회 측정된 자료 중 가장 수심이 깊게 측정된 날의 자료를 이용하였다. 1월과 2월의 데이터는 동절기로 인해 소양호 조사를 실시할 수 없어 제외하였다. 수온의 경우 30년간 서서히 증가하는 경향을 보였으며 0~90m 전반에 걸쳐서도 대체로 증가하는 경향을 보였다. 또한 6월에 성층현상이 더 심해지고, 겨울에는 연직운동이 감소하는 모습을 보였다. DO의 경우 용존산소가 중층에서 최저를 보이는 Metalimnetic oxygen minimum을 보였으며, 2008년까지는 거의 매년 농도 2.0mg/L 이하인 달이 있었으나 그 이후에는 회복되어 대부분 2.0 mg/L 이상을 보였다. 그러나 심층의 경우에는 2014년부터 DO 농도 3 미만으로 떨어지는 경우가 증가하였다.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.655-668
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• 2023

In radiography, an antiscatter grid is a well-known device for eliminating unexpected x-ray scatter. We investigate a new stationary grid artifact suppression method based on a nonsubsampled contourlet transform (NSCT) incorporated with Gaussian band-pass filtering. The proposed method has an advantage that extracts the Moiré components while minimizing the loss of image information and apply the prior information of Moiré component positions in multi-decomposition sub-band images. We implemented the proposed algorithm and performed a simulation and an experiment to demonstrate its viability. We did this experiment using an x-ray tube (M-113T, Varian, focal spot size: 0.1 mm), a flat-panel detector (ROSE-M Sensor, Aspenstate, pixel dimension: 3032 × 3800 pixels, pixel size: 0.076 mm), and carbon graphite-interspaced grids (JPI Healthcare, 18 cm × 24 cm, line density: 103 LP/inch and 150 LP/inch, ratio: 5:1, focal distance: 65 cm). Our results indicate that the proposed method successfully suppressed grid artifacts by reducing them without either reducing the spatial resolution or causing negative side effects. Consequently, we anticipate that the proposed method can improve image acquisition in a stationary grid x-ray system as well as in extended x-ray imaging.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.295-303
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• 2000

The water clarification efficiency was examined in a shallow wetland where dense vegetation was formed naturally in an abandoned paddy field. And, also two enclosure experiments were carried out to measure the effects of materials exchange between sediment and the overlying water with the existence of vegetation and accumulated litter. The hydraulic retention time of wetland was regulated in 1.2 day. The removal rates of SS (56%) and $NO_3-N$ (61%) were high, considering its short retention time. However, removal efficiencies of VSS (28%), COD (14%), DOC (1%),and TP (0.2%) were relatively lower. This low removal efficiencies were thought to be due to the release of dissolved form of organic matter and phosphorus from the sediment. Most of constituents except nitrate were higher in the enclosure at the beginning of enclosure installation than that of the outflowing water from wetland. And then, it has fluctuated and decreased with time. The wetland was in equilibrium state of settling, accumulation of organic debris, and regeneration of dissolved material from sediment. So ultimately high primary production by dense vegetation in the wetland may be the reason of unfavorable or low treatment efficiency of wetland after many years of operation for wastewater treatment. However, the water quality of effluent from the wetland showed smaller variation and better condition than that of inflow, especially during storm events. It can be concluded that this wetland is suitable for the improvement of water quality from nonpoint sources.

• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.206-214
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• 2001

Water quality and Pollution state of Lake Chungcho were evaluated during three years from 1998 to 2000. We surveyed physicochemical parameters, and TSI (trophic state index) was calculated using TP, Chl. a, and SD (secchi disc transparency) data of growing season average. Water samples were collected bimonthly except freezing season. During the study period, total annual precipitation in 1998, 1999 and 2000 year was 1,797,1,722 and 1,345 mm, respectively. Salinity and conductivity were high($29.3{\pm}5.5\;ppt$, and $45,105{\pm}7,585\;{\mu}S/cm$) then other lagoons in the Eastern Coast of Korea. Chemocline was formed by salinity at $0.5{\sim}1.5\;m$ water depth. As a result of this, DO concentration of hypolimnion was below $3.0\;mgO_2/L$. Especially, when intense chemocline was formed, temperature of hypolimnion was higher than epilimnion. Secchi disc transparency, chlorophyll a, and COD were $1.8{\pm}0.3\;m$, $15.7{\pm}20.7\;mg/m^3$, and $3.1{\pm}0.8\;mgO_2/L$, respectively. Most of TN/TP ratios below 20, but concentration of TN and TP was high. Values of TSI ranged between 59 and 77, indicating a eutrophic condition in this system.

• Korean Journal of Ecology and Environment
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• v.34 no.3 s.95
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• pp.175-184
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• 2001

The temporal and diel changes of cyanobacterial cell density, species composition, and cyanobacterial toxins (microcystin-RR, -YR, -LR) were examined for the outflow water of Lake Suwa in Japan from May to October, 1998. The highest total cell densities of Microcystis were observed in July and September, when the dominant phytoplankton was Microcystis ichthyoblabe and M. viridis, respectively. Both the species composition and total cell density of Microcystis affected the variation of the concentration of three microcystin variants. Only microcystin-RR(MC-RR) and -LR (MC-LR) were detected in July when Microcystis ichthyoblabe dominated, while microcystin-RR, -YR (MC-YR) and -LR were detected in August and October when Microcystis viridis dominated. The microcystin concentration and the cell density of Microcystis in the outflow water showed diel variations; the ratio of maximum to minimum value was $3{\sim}20$ fold far microcystin concentration, and $5{\sim}31$ fold for cell density. The diel variations of toxin concentration as well as Microcystis cell density was closely related to the diel variation of wind. During the windy period, when higher speeds occurred in the afternoon hours than morning hours, both the cell density of Microcystis and microcystin concentration tended to increase in the morning and decrease in the afternoon. The results of this study suggest that controlling the timing of lake discharge at the floodgate or intake tower can be useful for water resource management with respect to decreasing cyanobacteria biomass within intake water.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.256-260
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• 1993

Thirteen patients received a coralline hydroxyapatite sphere as a buried integrated ocular implant after enucleation surgery. The implant was modified by multiple drillings, 1 mm in diameter, to the center of the sphere to allow more rapid host tissue ingrowth. $^{99m}Tc$-MDP planar and tomographic bone scintigraphies were performed at various intervals after implantation (from 100 to 742 days after operation) to assess vascularization of the implant. All patients showed hot uptakes in the implants. These patients underwent a secondary drilling for the final motility peg application. The confirmation of vascular ingrowth was done by inspection of bleeding at the time of bleeding at the time of drilling from the center of the implant. Bleeding from the drilled implant was noted in all patients. In cnclusion, hot uptake in the implanted ocular hydroxyapatite implant accurately reflect vascular ingrowth into the implant.

• Korean Journal of Veterinary Pathology
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• v.3 no.1
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• pp.15-25
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• 1999

To elucidate the mechanism of age-related development in FGS/NgaKIST mice with spontaneous glomerulosclerotic lesion, we examined expression and localization of various cytokine mRNA in the kidney in the progression of diseases. This mouse model is the first to develop spontanously occuring glomerosclerotic lesion in the kidney. In this study, we detected the up-regulation of local cytokine genes such as IL-1$\beta$, IL-2, IL-6, IL-10, TNF-$\alpha$, TGF-$\beta$, and IFN- $\gamma$ in the kidneys. In RT-PCR and Southern blot analysis, we detected gradual expressions of cytokine mRNA of IL-1$\beta$, IL-2, IL-6, IFN- $\gamma$, and TNF $\alpha$ mRNA during the course of disease. Other cytokines including IL -10 and TGF -$\beta$ were found to be appeared the slightly expressed level at 3 to 12 weeks before onset of inflammatory lesion but they are highly expressed at the end-stage of the disease accompaning high proteinurea and wasting. In situ RT-PCR, each cytokine mRNA were specifically localized in a variety of cells including mesangial, endothelial, parietal epithelial, tubular epithelial, arterial muscle cell, and infiltrated inflammatory cells. In addition, TNF - $\alpha$was detected moderately in the visceral and parietal epithelial cell, but weakly in endothelial and mesangial cells, whereas IL-1 $\beta$ and IL -6 were strong in mesangial regions. IL-6 and TNF- $\alpha$ was highly localized in the damaged proximal and collecting tubules. Especially, TGF -$\beta$ mRNA was highly found in mesangial cells within glomerulus and interstitium during the end-stage of this disease.. These results indicate that pro inflammatory cytokines such as IL-1 $\beta$, IL-2, IL-6, and TNF- $\alpha$ were gradually expressed from the early stage of this disease to the end-stage, and that IL-10 and TGF-$\beta$ may be important in the accumulation of extracellular matrix(ECM) within glomerulus and periglomerular fibrosis in the progression of this disease as well as tissue destruction in end-stage of this disease.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.495-495
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• 2017

도시화는 불투수면의 증가를 야기 시켜 물순환 왜곡, 다양한 오염 물질의 유입으로 인한 비점오염물질 유출, 인공 배출열의 증가로 인한 도시열섬효과 등 다양한 문제를 유발한다. 이러한 수리수문학적 및 환경생태학적 문제를 저감하기 위하여 도시지역과 같은 개발 사업에서는 수환경을 가능한 자연 상태로 복원하는 저영향개발(Low Impact Development, LID)기법이 중요한 대안으로 제시되고 있다. LID기법 중 하나인 옥상녹화는 에너지 이용을 최소한으로 한 자연 녹음의 효과적인 이용을 도모하여 환경공생도시 조성과 식물을 매개로한 자연 순환 과정을 도시구조에 도입하여 순환 시스템 재생이 가능 하도록한다. 노지녹화는 두꺼운 자연 토양을 이용하는 반면 옥상녹화는 적재하중의 제약(옥상의 적재하중 조건은 $150{\sim}180kgf/m^2$이다. 비중이 1.6~1.8인 토양을 20cm 객토한 경우, 약 $320kgf/m^2 $이상의 적재하중이 되기에 식재기반의 경량화는 중요한 사안이다.)으로 인해 용적밀도가 작은 인공경량토양 또는 개량토양을 이용하며, 토양 두께도 얇게 설정된다. 또한 토양의 두께는 식물의 크기와 종류 및 토양의 조성에 따라 다르기에 적재하중 조건을 고려한 적절한 토양과 식재 식물의 크기와 종류 결정은 중요하다. 이에 본 연구에서는 옥상녹화식생에 대한 평가와 이에 대한 시험 프로세스가 가능한 실험 장치를 개발하였다. 옥상녹화 효율성 검증실험장비는 1m*1m*0.6m 아크릴 재질의 녹화셀로 경사조절이 가능하도록 설계하여 경사변화에 따른 유출, 침투, 증발산량의 탄성도 모의 평가를 할 수 있다. 또한 4점식 형태의 로드셀을 이용하여 녹화셀에서 발생하는 증발산량을 측정하고 관측된 증발산량은 RS-232c 이상의 통신프로토콜을 사용하여 주기적인 관측치의 송수신이 가능하며 주기적 자료송수신 외에도 옥상 녹화셀의 측면에 하중 표시기를 설치하여 관측이 가능하다. 또한 저면에 바퀴설치를 통하여 이동 실험이 용이하며 현재 부산대학교 양산캠퍼스 한국 GI&LID 실증단지 연구센터 내 옥상녹화 실험장에 옥상녹화 효율성 검증 실험 장비를 설치하여 자연 혹은 인공강우를 통한 유출, 침투, 증발산량의 시험계측을 실시중이다. 이러한 옥상녹화 효율성 검증실험장비는 최대 하중 2,000kg, 측정해상도 0.02kg 이상을 허용하는 로드셀과 녹화셀을 이용하여 하중을 고려한 식생의 종류에 따른 평가가 가능하므로 최적 식재기반 단면구조 개발에 이용될 수 있을 것이다. 또한 토양 함수량 변화 측정으로 옥상녹화에 이용되는 다양한 종류의 식물의 염분에 대한 저항성과 식물의 성장능력을 평가하여 녹화공간에 따른 옥상녹화에 사용할 식생을 결정할 수 있다.