• Journal of Photoscience
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• 제9권2호
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• pp.55-58
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• 2002

The reaction center Dl protein of photosystem II is the target of photodamage by excess illumination. The Dl protein is damaged by reactive oxygen species generated by photochemical reactions and then degraded by specific proteolytic enzymes. We found that the Dl protein also cross-links with the surrounding polypeptides, such as D2 and CP43 in isolated thylakoids or photosystem II-enriched membranes from spinach under the illumination with strong visible light. The cross-linking was observed in spinach leaf discs as well when they were illuminated at higher temperature (40°C). It was also shown that the cross-linked products are digested efficiently by a protease(s) in the stroma. Thus the cross-linking/digestion processes of the Dl protein seem to comprise a new pathway in the turnover of the photodamaged Dl protein. It should be noted, however, that the cross-linked products of the Dl protein and CP43 induced by endogenous cationic radicals in the donor-side photoinhibition are resistant to proteolytic digestion. Accumulation of these cross-linked products in the thylakoids may lead to the decay of the function of chloroplasts and finally to the death of plant cells. Thus, we suggest that the quality control of photosystem II, especially removal of the cross-linked products of the Dl protein, is crucial for the survival of chloroplasts under the light stress.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2075-2088
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• 2017

Salmonella is one of the principal causes of foodborne outbreaks. As traditional control methods have shown less efficacy against emerging Salmonella serotypes or antimicrobial-resistant Salmonella, new approaches have been attempted. The use of lytic phages for the biocontrol of Salmonella in the food industry has become an attractive method owing to the many advantages offered by the use of phages as biocontrol agents. Phages are natural alternatives to traditional antimicrobial agents; they have proven effective in the control of bacterial pathogens in the food industry, which has led to the development of different phage products. The treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases, and ultimately promotes safe environments for animal and plant food production, processing, and handling. After an extensive investigation of the current literature, this review focuses predominantly on the efficacy of phages for the successful control of Salmonella spp. in foods. This review also addresses the current knowledge on the pathogenic characteristics of Salmonella, the prevalence of emerging Salmonella outbreaks, the isolation and characterization of Salmonella-specific phages, the effectiveness of Salmonella-specific phages as biocontrol agents, and the prospective use of Salmonella-specific phages in the food industry.

• Journal of the Korean Wood Science and Technology
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• 제20권3호
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• pp.55-60
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• 1992

Japanese red pine (Pinus densiflora S. et. Z.) decayed by brown-rot fungi Tyromyces palustris and Gloeophyllum trabeum were subjected to X-ray diffraction analysis and infrared spectral examinations. Pine woods decayed by T. palustris showed the increase of relative crystallinity in the initial stage of degradation. When the weight loss was above 30%, then the crystallinity went down slowly. In contrast, the wood samples degraded by G. trabeum showed the decrease of crystallinity from the beginning stage of decay. The changes of crystallinity in brown-rotted woods suggested that the degradation rate of crystalline cellulose was varied with the brown rot fungal species. X-ray diffraction analyses also indicated that crystalline cellulose was much more slowly broken down than the amorphous one. The most notable difference in the IR spectra of the brown-rotted wood samples was that the adsorption band centered at 1,730$cm^{-1}$ was significantly diminished in the decayed wood. indicating the degradation of hemicellulose by brown-rot fungi. However, no marked changes of intensities at 1,000, 1,060 and 1,040$cm^{-1}$ were observed in the brown rotted wood samples, suggesting that crystal line cellulose was resistant against the attack by brown rot fungi.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.510-517
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• 2019

Increasing proliferation resistance of plutonium by way of increased $^{238}Pu$ content is of interest to the nuclear nonproliferation and international safeguards community. Considering the high alpha decay heat of $^{238}Pu$, increasing the isotopic fraction leads to a noticeably higher amount of heat generation within the plutonium. High heat generation is especially unattractive in the scenario of weaponization. Upon weaponization of the plutonium, the plutonium may generate enough heat to elevate the temperature in the high explosives to above its self-explosion temperature, rendering the weapon useless. In addition, elevated temperatures will cause thermal expansion in the components of a nuclear explosive device that may produce thermal stresses high enough to produce failure in the materials, reducing the effectiveness of the weapon. Understanding the technical limit of $^{238}Pu$ required to reduce the possibility of weaponization is key to reducing the current limit on safeguarded plutonium (greater than 80 at. % $^{238}Pu$). The plutonium vector evaluated in this study was found by simulating public information on Lightbridge's fuel design for pressurized water reactors. This study explores the temperature profile and maximum stress within a simple (first generation design) hypothetical nuclear explosive device of four unique scenarios over time. Analyzing the transient development of both the temperature profile and maximum stress not only establishes a technical limit on the $^{238}Pu$ content, but also establishes a time limit for which each scenario would be useable.

• Journal of Forest and Environmental Science
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• 제25권1호
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• pp.1-24
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• 2009

Teak (Tectona grandis) is one of the most valuable timber yielding species in the world, with predominant distribution in tropical or sub-tropical countries. However, natural teak available only in few countries like India, Myanmar, Laos People's Democratic Republic and Thailand. Teak grows well in deep, well-drained alluvial soils, fairly moist, warm, tropical climate with pH ranges from 6.5-7.5. Teak is cultivated in many Asian, African and South American countries for timber production. The global teak plantations are estimated to be three million hectare with major share in India (44%) followed by Indonesia (33%). India is considered as richest genetic resources of teak with large areas of natural teak bearing forests (8.9 million ha), plantations (1.5 million ha), clonal seed orchards (1000 ha) and seed production areas (5000 ha). The studies on diversity of teak populations showed that teak is an out crossing species with major portion of diversity present within the populations. The productivity and quality of teak timber varies depending upon the site and environmental conditions. Teak wood is moderately heavy, strong and tough,straight grained, coarse textured and ring porous with specific gravity varies from 0.55 to 0.70. The sapwood is white to pale yellow in colour and clearly demarcated while heartwood is dark brown or dark golden yellow in colour. Teak is one of the most durable timbers in the world, practically, impervious to fungus and white ant attack and resistant to decay. Teak wood is used in ship and boat constructions, furnitures and aesthetic needs. Genetic improvement programmes have been undertaken in countries like Thailand, India, Malaysia and Indonesia. The programme includes provenance identification and testing, plus tree selection and clonal multiplication, establishment of seed orchards and controlled hybridization. Several aspects like phenology, reproductive biology, fruit characteristics, silvicultural practices for cultivation, pest and diseases problems, production of improved planting stock, harvesting and marketing, wood properties and future tree improvement strategy to enhance productivity have been discussed in this paper.

• Journal of the Korean Wood Science and Technology
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• 제28권3호
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• pp.52-61
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• 2000

아까시나무와 현사시나무를 채취, 건조하고 아세톤-물의 혼합용액으로 추출한 후 hexane, chloroform, ethylacetate 및 물 분획으로 분류하고 동결건조하여 갈색 분말로 조제하였다. 각각의 분획은 메탄올-물 및 에탄올-헥산의 혼합용액으로 Sephadex LH-20 칼럼상에서 크로마토그래피를 수행하였다. 아까시나무의 목질부 추출성분은 (+)-leucorobinetinidin과 같은 flavan 화합물과 robtin, dihydrorobinetin 및 robinetin 등의 flavanonol 화합물을 포함하며 현사시나무의 수피 추출성분은 (+)-catechin과 naringenin, eriodictyol, sakuranetin, aromadendrin 및 taxifolin 등의 후라보노이드 화합물, 그리고 살리신 유도체인 salireposide 및 소량의 aesculin과 쿠마린산 등 다양한 종류의 페놀성 화합물로 구성되어 있었으며 aesculin은 현사시나무의 수피 조성분에서는 아직 우리 나라에서 보고되지 않았다. 단리된 페놀성 성분의 구조 분석을 위하여 NMR 및 FAB-MS 분석을 수행하였다.

• 대한소아치과학회지
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• 제25권3호
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• pp.598-603
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• 1998

본병원 소아치과에 내원한 유치와 영구치 모두에 법랑질 형성 부전증을 가지고 있는 환자에 대해 교합면의 마모를 방지하여 교합고경을 유지하기 위해 유구치부 stainless steel crown 및 맹출 중인 제 1 대구치에 sealant, 전치아에 걸쳐서 주기적인 불소도포를 이용해 치료하여 양호한 결과를 얻었다.

• The Korean Journal of Physiology and Pharmacology
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• 제28권4호
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• pp.335-344
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• 2024

Diphenyleneiodonium (DPI) has been widely used as an inhibitor of NADPH oxidase (Nox) to discover its function in cardiac myocytes under various stimuli. However, the effects of DPI itself on Ca²⁺ signaling and contraction in cardiac myocytes under control conditions have not been understood. We investigated the effects of DPI on contraction and Ca²⁺ signaling and their underlying mechanisms using video edge detection, confocal imaging, and whole-cell patch clamp technique in isolated rat cardiac myocytes. Application of DPI suppressed cell shortenings in a concentration-dependent manner (IC₅₀ of ≅0.17 µM) with a maximal inhibition of ~70% at ~100 µM. DPI decreased the magnitude of Ca²⁺ transient and sarcoplasmic reticulum Ca²⁺ content by 20%-30% at 3 µM that is usually used to remove the Nox activity, with no effect on fractional release. There was no significant change in the half-decay time of Ca²⁺ transients by DPI. The L-type Ca²⁺ current (I_Ca) was decreased concentration-dependently by DPI (IC₅₀ of ≅40.3 µM) with ≅13.1%-inhibition at 3 µM. The frequency of Ca²⁺ sparks was reduced by 3 µM DPI (by ~25%), which was resistant to a brief removal of external Ca²⁺ and Na⁺. Mitochondrial superoxide level was reduced by DPI at 3-100 µM. Our data suggest that DPI may suppress L-type Ca²⁺ channel and RyR, thereby attenuating Ca²⁺-induced Ca²⁺ release and contractility in cardiac myocytes, and that such DPI effects may be related to mitochondrial metabolic suppression.

• 핵의학기술
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• 제20권1호
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• pp.28-31
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• 2016

전립선암은 세계적으로 남성에게 발생하는 가장 흔한 암이며, 암 관련 이환 및 사망의 주요 원인 중 하나이다. 전립선 암세포는 안드로겐에 의해 자극되며 안드로겐 수용체에 결합하여 활성화된다. 안드로겐 수용체는 전사인자로 작용하며 세포주기, 증식 및 분화를 조절한다. 안드로겐 수용체 신호 차단은 전립선암 치료의 특징이다. 전립선암에서 통증은 빈번하게 일어나는 관련 증상으로 환자의 삶의 질 악화의 주요 원인 중 하나이다. 주사용 $^{223}Ra-Dichloride$는 28 Mev 알파 방사선을 방출하여 골 전이가 있는 거세저항성 전립선암(Castration-Resistant Prostate Cancer)의 치료에 이용되고 있다. $^{223}Ra$은 체내 반감기가 11.4 일, 100 마이크로미터 이하 범위의 높은 선 에너지 전달(LET) 알파선을 방출하므로 매우 국소적인 방사선 영역을 생성시키는데 사용할 수 있다. 골격 전이와 같은 표적조직에 알파선을 위치하게 되면 베타선보다 더 국소적 용적으로 방사선을 전달하여 주위의 정상조직에 대한 노출을 줄인다. 하지만 $^{223}Ra-Dichloride$는 알파선 이외에 붕괴 과정에서 3.6%의 베타선과 1.1%의 감마선 (80, 156, 270 keV)을 방출한다. 본 연구는 $^{223}Ra-Dichloride$ 치료 시 사용되는 방사능양 3.5 MBq과 $^{99m}Tc-MDP$를 사용하여 Bone scan 검사 시 사용되는 방사능양 740 MBq을 사용하여 감마선에 대한 외부 방사선량을 평가해보고자 하였다. 최대 외부 방사선량은 $D({\infty})=34.6{\tau}Q_0Tp(0.25)$(${\tau}$:감마상수, $Q_0$:초기방사능양, Tp:물리적 반감기) 식을 이용하여 산출하였으며, 실제로 vial에서 방출되는 감마선을 1m의 거리에서 survey meter를 이용하여 15회 외부 방사선량률을 측정하였다. Health physics(2012)에서 제공하는 $^{223}Ra-Dichloride$과 $^{99m}Tc-MDP$의 1m 거리에서의 감마상수의 값은 각각 0.0469, 0.0215, 실제로 사용되는 방사능양 3.5 MBq, 740 MBq, 반감기 11.4일, 6시간을 기준으로 산출된 외부 방사선량은 $^{223}Ra-Dichloride$은 $16{\mu}Sy$, $^{99m}Tc-MDP$은 $34{\mu}Sy$의 값을 보였다. 실제로 vial에서 1 m 거리에서 방출되는 외부 방사선량율은 평균 $^{223}Ra-Dichloride$는 ${\mu}Sy/h$, $^{99m}Tc-MDP$은 $18{\mu}Sy/h$ 값이 측정값을 보였다. 감마상수 값은 $^{223}Ra-Dichloride$이 $^{99m}Tc-MDP$에 비해 높은 값을 나타내지만 실제로 사용되는 방사능의 양을 고려한 최대 외부 방사선량은 $^{223}Ra-Dichloride$이 $^{99m}Tc-MDP$보다 낮은 최대 외부 방사선량 값이 산출되었으며, 실제로 측정한 외부 방사선량율도 작은 값을 보여 $^{223}Ra-Dichloride$을 이용한 치료시 감마선에 대한 외부 방사선량은 매우 작음을 알 수 있었다. $^{223}Ra-Dichloride$은 골 전이가 있는 거세저항성 전립선암(Castration-Resistant Prostate Cancer) 환자들에게 유용한 치료제라고 사료된다.

• Applied Biological Chemistry
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• 제11권
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• pp.123-130
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• 1969

고구마의 장려품종(奬勵品種)인 충승 100호, 수원(水原) 118호(號), 수원(水原) 147호(號), 신미(千美), 신미(新美)의 오품종(五品種)에 대하여 저장성(貯藏性), 가공적성(加工適性) 및 새로운 가공식품(加工食品)으로서 고구마칩의 제조조건(製造條件)에 관한 실험을 하여 다음과 같은 결과(結果)를 얻었다. 1) 공시품종(供試品種) 중에서 냉해(冷害) 및 연부병(軟腐病)에 대한 저항성(抵抗性)을 보면, 천미(千美), 수원(水原) 147호(號)가 가장 컸고 기타 3품종(品種)은 비교적 적었다. 2) 고구마중의 수지함량(樹脂含量)과 polyphenol 함량(含量)은 품종(品種)에 따라 많은 차이(差異)가 있었다. 3) 고구마의 품종(品種)에 따라 색상(色相)이 다른 고구마칩을 제조(製造)할 수 있었고 튀김용 기름으로는 채종유(採種油)가 최적(最適)임 을 알았다. 4) 고구마칩 제조방법(製造方法)으로는 두께 $1{\sim}2mm$의 박편(薄片)을 $40^{\circ}C$의 0.25% 산성아황산(酸性亞黃酸) 소다 수용액에 $30{\circ}40$분 침지(浸漬)한 후 $150{\sim}160^{\circ}C$의 유용(油溶)에서 $2.5{\sim}3.5$분간(分間) deep frying 하는 것이 선명(鮮明)한 색과 적당한 texture의 고구마칩을 얻는데 최적조건(最適條件)임을 확인(確認)하였다. 5) 고구마칩의 포장재료(包裝材料)로서는 polyethylene-cellophane film 이 방습도(防濕度) 및 파열강도(破裂强度)에 있어서 가장 우수(優秀)함을 확인(確認)하였다.