• Journal of Radiation Protection and Research
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• 제42권1호
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• pp.33-41
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• 2017

Background: Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., $^{238}U$ and $^{226}Ra$), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, $^{238}U$, $^{232}Th$, $^{226}Ra$, and $^{40}K$ levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Materials and Methods: Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of $^{238}U$, $^{232}Th$, $^{226}Ra$, and $^{40}K$. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. Results and Discussion: The concentration ratios of $^{226}Ra$ and $^{238}U$ in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was $^{40}K$, and the median $^{40}K$ activity was $8.972Bq{\cdot}g^{-1}$ and $1.496Bq{\cdot}g^{-1}$, respectively. For the $^{238}U$ series, the activity of $^{238}U$ and $^{226}Ra$ was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Conclusion: Although the activity of $^{40}K$ in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of $^{226}Ra$ and $^{238}U$ in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing.

• 해양환경안전학회지
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• 제2권1호
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• pp.137-150
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• 1996

Safety is built in to the activities of the prudent ship operator. Ant investment made towards this end is likely to have a measurable payback in positive terms. That there must be an investment is inevitable, because the industry at large has let things slip too far too long. Those who have not allowed it to slip too far and who are the first to recognize that safety, far from costing money, in the long term actually preserves it, will be wieners. Too many seem to have lost sight of the fact that every one hundred pennies saved is a full one hundred pennies profit. Every hundred pennies of additional revenue contributes no more then fifteen pence to profit. Environmental protection is not so simple, nor so financially attractive. Man needs the minerals of the Earth as well as the products of the soil and sea survive. We(the human race) are still not in the position, politically or financially to manage the Earth's assets without causing damage. The evidence of our damage is evident in many different parts of the Glove and will in some cases haunt several generations still to come. We have learned a lot, and continue to learn, but despite the best intentions some Government needs for their people will be at the expense of people in another region for the foreseeable future. We sailors ply the seas with the raw materials of commerce as well as the finished and part finished goods. It does not always sit well to consider too deeply what effect the ship and the cargo it carries is having, or may have, on some communities, or on the sea through which sail. None my generation can hold up his head and claim to be without blame in the pollution of the seas. Times are changing though, and Governments are turning their attention more to the protection of our planet and its precious resources. This will not be without cost. The investment will have to be made not for our benefit, but for the benefit of generations yet to come, however the cost will have to be borne by society as a whole, not by the shipping community alone. The debate surrounding the choice between engineering our way to a better tomorrow, or adapting our working practices will continue. Each method has the same goal as its target and as long as we attain the goal does it really matter how we get there?

• 생명과학회지
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• 제27권9호
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• pp.1003-1010
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• 2017

Paenibacillus woosongensis의 유전체 부분 염기서열로부터 mannanase를 코드하는 것으로 유추되는 open reading frame을 중합효소연쇄반응으로 증폭하여 대장균에 클로닝하고 염기서열을 결정하였다. Mannanase 유전자는 man26AT로 명명하였으며 1,053 아미노산으로 구성된 단백질을 코드하는 3,159 뉴클레오티드로 이루어졌다. 아미노산 잔기배열을 분석한 결과 Man26AT는 glycosyl hydrolase family 26의 mannanase와 상동성이 높은 활성영역, 탄수화물 결합영역 CBM27과 CBM11로 구성되어 있었다. Man26AT의 아미노산 배열은 P. ihumii의 유추된 mannanase와 상동성이 81%이고 다른 Paenibacillus 속 균주의 여러 mannanases와 57% 이하의 상동성을 보였다. man26AT 유전자를 함유한 재조합 대장균의 균체 파쇄상등액은 $55^{\circ}C$와 pH 5.5에서 최대의 mannanase 활성을 보였고, $50^{\circ}C$에서 1시간 열처리한 후에 80% 이상의 잔존활성을 보였다. Man26AT는 locust bean gum (LBG) galactomannan과 konjac glucomannan에 대한 분해활성이 유사하였으며, carboxymethylcellulose, xylan과 para-nitrophenyl-${\beta}$-mannopyranoside는 분해하지 못하였다. Man26AT에 의해 mannotriose, mannotetraose, mannopentaose와 mannohexaose 등의 만노올리고당이나 LBG로부터 공통의 최종 가수분해 산물로 mannose, mannobiose와 mannotriose가 생성되었다. 또한 mannotriose 보다 큰 만노올리고당이 LBG와 guar gum의 분해산물로 각각 생성되었다. 그러나 Man26AT는 mannobiose를 분해하지는 못하였다. 활성염색을 통해 Man26AT는 균체 내에서 3개 이상의 크기가 다른 활성 단백질로 분해된 것이 확인되었다.

• 한국환경과학회지
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• 제1권1호
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• pp.51-59
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• 1992

Two comparative poplar clones (I-214: Populus euramerinm, Peace: P koreana x p. trihocarpa) were exposed to two $CO_2$ concentrations (350 or 2, 000 ${\mu}L L^{-1} CO_2$) for 21 days. When both poplar clones were compared at growth conditions, the net photosynthetic rate ($P_N$) in $CO_2$-enriched ($2, 000{\mu}L L^{-1} CO_2 = C_{2, 000}$) plants become about 50-60% higher than that of 350 ${\mu}L L^{-1} CO_2 (=C_{350}$ Plants on 7 days treatment. But the enhancement of PN by high $CO_2$ was not maintained throughout all the experimental period. At 21 days, there was no difference of photosynthetic rates between $C_{350}$ and $C_{2000}$ plants. In contrast with photosynthesis, the response of leaf conductance to the elevated $CO_2$ concentration was very different between I-214 and Peace. During all experimental period, leaf conductance ($g_{s}$) of $C_{2000}$ plants is 50% lower than that of the $C_{350}$ plants for I-214, while there is no difference of gs between the plants of $C_{350}$ and $C_{2, 000}$ for Peace. The results of gs in Peace indicate that decreased photosynthetic rate after 21 days in $C_{2, 000}$ Plants for two poplar clones is possibly due to non-stomatal factors. To investigate the non-stomatal factors, starch accumulation and ribulose-1, 6-bisphosphate carboxylase (RuBPCase) were measured. We found significant accumulation of starch in two poplar clones exposed to high $CO_2$, especially starch of I-214 in $C_{2, 000}$ become 3.5 times higher than in $C_{350}$ plants at 21 days. This suggests that high proportion of photosynthates was directed into starch. After 21 days, the activity of ribulose-1, 6-bisphosphate carboxylase of $C_{2, 000}$ plants become decreased in 40-50% compared with that of the $C_{350}$ plants. Two poplar clones show the same trend to RuBPCase declines under high $CO_2$ concentration, although the decline is more significant for I-214. The results reported here suggest that starch accumulation and decreased RuBPCase activity in $C_{2, 000}$ plants can be partly ascribed to the loss of photosynthetic efficiency of high $CO_2$-grown poplar plants.

• 한국산림과학회지
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• 제96권2호
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• pp.170-177
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• 2007

The objectives of this study were to select early, late, and abundant flowering trees of black locust from domesticated and introduced cultivars, and prediction of flowering period by calculation of accumulated temperature in spring. Four cultivars (Debreceni-2, Pusztavacs, Jaszkiseri, and Rozsaszin AC) from Hungary and a cultivar from Beijing, China, were introduced, propagated by seed and planted in a seed orchard. For domesticated black locust, 63 cultivars from 10 locations throughout the country were selected and propagated by root cutting. Criteria for selection of domesticated cultivars were abundant flowering, long flowering period, or abundant nectar production with, if possible, straight stems. Accumulated temperature was calculated from data of a nearby weather station by accumulating daily maximum temperature minus 5 degree Celsius from January 1 up to the date reaching 880 degrees. Daily mean temperature was also used to calculate accumulated temperature up to the date reaching 450 degrees. The percentages of two-year and three-year-old flowering trees propagated by root cutting were higher than that of trees propagated by seeds, while four-year-old trees all flowered regardless of propagation methods. Among the domesticated cultivars, all the cultivars from Ganghwa showed abundant flowering with highest nectar production of 6.5 ul per flower, which was 100% more than other domesticated cultivars and 50% more than Debreceni-2 cultivar with highest nectar production among the introduced cultivars from Hungary. At the end of the eight years of observations, two trees of Debreceni-2 cultivars and a tree from Beijing, China were selected for early flowering trees which flowered 2 to 3 days earlier than average trees, while a tree of Debeceni-2 and three trees from Bejing were selected for late flowering trees which flowered 2 to 3 days later than average trees. It is possible to extend the flowering period of black locust by 4 to 6 days by planting early and late flowering cultivars together. Abundant flowering trees were unable to be selected due to severe damages by leaf gall midges which killed many trees and reduced the crown size of the remaining trees in the seed orchard, and which were first found in Korea in 2001 and now damaging most of the black locust forests in Korea. The prediction of flowering period by accumulated temperature indicated that black locust flowered to a peak when accumulated daily maximum temperature reached 880 degrees Celsius, and when daily mean temperature reached 450 degrees.

• 대한예방한의학회지
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• 제12권2호
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• pp.13-25
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• 2008

The purpose of this study was to investigate extract from mixed culture with Trichloloma matsutake mycelium in oriental medicine and cereal medium(OCM) to develop new material for pharmaceutical products and medicinal food for diabetes mellitus. To evaluate of hypoglycemic activity of OCM extracts, we examined the inhibitory activity of ${\alpha}$-glucosidasein OCM, blood glucose level and liver function of streptozotocin(STZ) induced diabetic rat. Experimental group was divided into 6 groups: first, it was divided into normal control group(hereafter NC group) and diabetes-induced group, and diabetes-induced group was subdivided into diabetic control group(DC group), treated by hot water extracts group(HE), ultra sonic waves, micro waves, and micro bubble extracts g roup(UE), crude polysaccharide of HE group (HEE) and crude polysaccharide of UE group(UEE) at a dose of 300mg/kg/body weight, respectively. In diabetic-induced groups, after streptozotocin was melted in 0.01M citrate buffer at 50mg/kg/body weight, when the non-fasting blood glucose levelwas 300 mg/dl or more in blood collected from the tail vein, it was regarded as diabetic induction and then such diabetic-induced experimental animals were used in this experiment. At the end of the experiment, blood glucose level increased by 4.19% in DC group but significantly decreased by 32.34%, 19.19%, 17.81% and 17.64%, respectively in UEEE, UE, HE, and HEE groups. In the cases of AST, ALT, and ALP, the experiment group treated with extracts showed significantly lowerblood glucose level than DC group. The levels of BUN and uric acid were found to be lower in the UMPM extract group(UE) than HW extract group(HE), which implies that herb medicine medium extracts in which Tricholoma matsutake mycelia were cultured are effective in reducing impaired liver function as well as high blood glucose level caused by diabetes. In addition, the administration of low temperature UMPM extracts was found to produce better results than that of high temperature hot water extracts. In this regard, it is expected that extracts from herb medicine obtained by cultivating Tricholoma matsutake mycelia will be widely used as new ingredients for foods and medicines for prevention and treatment of diabetes.

• 한국가스학회지
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• 제7권1호
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• pp.19-23
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• 2003

최근 국내에서도 정량적 위험성 평가 기법을 위험시설물에 도입하여 위험도를 관리하면서 LPG 저장탱크에 대한 사고후 피해영향평가에 대한 연구는 다각적으로 이루어지고 있으나 BLEVE(Boiling Liquid Expanding Vapor Explosion, BLEVE)의 조건 및 메커니즘 규명에 대한 연구는 별로 이루어지고 있지 않다. 따라서, 본 고에서는 상대적으로 위험성이 큰 지상식 LPG 저장탱크의 BLEVE 가능성에 대해 외국의 Pilot 탱크 시험 결과 및 BLEVE 발생을 위한 소요입열량 계산값을 이용한 연역적 계산방법을 통해 BLEVE 조건 및 가능성을 정량화하여 규명코자 하였다. 또한, 산출된 탱크의 파열압력(burst pressure)과 충전량에 의해 보정된 액 온도를 사용해서 그려진 BLEVE map을 이용하여 BLEVE 조건에서 액위($\%$)가 BLEVE에 어떤 영향을 미칠 것인가를 규명하였다. 계산결과, 탱크 plate 온도가 $600^{\circ}C$이고, 탱크내부 액온도가 $53^{\circ}C$ 일 때 액충전량은 $43.68\%$ 이상일 경우에 BLEVE의 발생이 가능하다는 결과를 얻었다. 또한, 부천 대성에너지 LPG 충전소와 동일한 사양인 15톤 프로판 탱크를 모델로 하여 BLEVE가 발생하기 위한 외부 누출 및 외부화재 조건을 PHAST(Version 6.00) 및 EFFECTS(Version 2.1) 프로그램을 이용해 계산한 결과 액상 누출시 누출상당직경은 7.2mm, 이상 누출시 누출상당직경은 17.6mm 이상일 경우에 BLEVE가 발생 가능한 최소한의 풀화재 생성조건이 되었고, 풀화재의 크기는 최소 직경 3.3m, 높이 10.4m 이상의 풀화재가 전제되어야 한다는 결과를 얻을 수 있었다.

• Applied Microscopy
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• 제23권2호
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• pp.53-77
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• 1993

In this study, an attempt was made to investigate the probable organelles participating in the secretion of biligrafin. The animals (ICR male mice, 25-30gm) were divided into normal control and 6 biligrafin injected groups to which 30% biligrafin (0.006ml/gm b.w.) were injected at 10, 20, 40, 80, 160 and 320 min prior to the sampling. The mice of each group were perfused through the heart with ice-cold 2.5% glutaraldehyde buffered with 0.1M Na-cacodylate (pH. 7.4) under the Na-pentobarbital (Nembtal 0.0015mg/gm b.w.) anesthesia and liver tissues were taken from each group. Some specimens were immersed 1 hr in the same solution used in the perfusion. After an overnight rinse in 0.1M Na-cacodylate buffer containing 10% DMSO and 7.6% sucrose, $75{\mu}m$ fronzen sections were made for cytochemical study. The sections were incubated in thiamin pyrophosphatase (TPPase) and inosine diphosphatase (ID Pase) media for 70 min at $37^{\circ}C$ respectively and acid phosphatase (AcPase) medium for 40 min at $37^{\circ}C$. They were postfixed in 1 % $OsO_4$ for 1 hr. The other specimens were immersed for 8 hrs in the fixative consisting of 2.5% glutaraldehyde and 3.0% paraformaldehyde buffered with Na-cacodylate (pH. 7.4). All of the osmificated specimens were processed for electron microscopy. In both normal and biligrafin injected groups, endoplasmic reticulum (ER), vacuoles, Golgi apparatus and lysosomes were seen in the vicinity of bile canaliculus. In the biligrafin injected groups, however, the Golgi apparatus appeared to be decreased and ER and vacuoles were dilated and increased. The rough endoplasmic reticulum (RER) having a few attached ribosomes appeared to be the round saccule, especially at 20 min after biligrafin injection. Smooth endoplasmic reticulum (SER) seemed to be formed by the detachment of ribosomes at the cisternal end of RER. The cistern of SER showed saccules which probably budded off to form the vacuole. The vacuoles were devoid of visible centents. This finding seemed to be in agreement with the biochemical property of the bile constituents. The fusion between the vacuoles and bile canaliculus were frequently seen in the groups injected with biligrafin. The lysosome did not show any changes in the biligrafin injected groups. Accumulation of some material and lipid droplets were seen at the 40 and 80 min after biligrafin injection, especially at the latter. At 160 and 320 min after biligrafin injections, however, they were decreased successively while the RER stack, free ribosomes and polysomes were increased. Although the reactive products of TPPase and IDPase were observed in the ER saccules and vesicles of the normal control and biligrafin injected groups, the fusion between the bile canaliculus and saccules or vesicles could easily be seen in the latter. The AcPase activity, however, was observed in the cistern at the maturing face of Golgi apparatus and lysosomes in both normal and biligrafin groups. The results suggest that the biligrafin is excreted via the vesicles, vacuoles or sacoules probably derived from the SER without the participation of Golgi apparatus and lysosomes, and the excess amount of material is stored as inclusions during the repairing of the organelles being overactive.

• 한국식생활문화학회지
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• 제3권4호
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• pp.391-396
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• 1988

약식의 유통기간을 결정하는 중요한 품질요소인 조직감의 경화현상을 측정하는 방법을 수집하고 제조방법과 저장조건에 의한 경화속도의 변화를 조사하였다. 전통적으로 사용되는 표준 제조방법으로 만든 약식은 실온 $(20{\circ}C)$에서 3일간 저장할 수 있었으며 유통 상한점에서의 경도는 multipuncture시험의 700g 하중 수준이었다. 냉장저장$(5^{\circ}C)$에 의하여 약식의 굳는 속도는 급격히 증가하였으며 Avrami식으로 산출한 속도상수비는 $1.3{\sim}3.3$배 증가하였으며 수분함량이 높은 압력솥 처리구가 가장 큰 차이를 나타내었다. 물엿첨가는 약식의 경화속도를 다소 낮추는 효과를 나타내었다. 압력솥 처리에 의하여 약식은 너무 무르게 되어 기호도가 다소 떨어지나 냉장보관시에는 저장기간을 연장할 수 있는 방법으로 사료된다. 전자렌지로 조리한 약식은 대단히 높은 경도를 나타내었다. 약식의 종합적인 기호도는 조직감 기호도와 높은 정의 상관관계를 나타내며, 조직감 기호도는 multipuncture 시험의 최대 하중과 높은 부의 상관관계를 나타내어 multipuncture 시험이 약식의 품질평가 방법으로 사용될 수 있음을 확인하였다.

• Current Research on Agriculture and Life Sciences
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• 제14권
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• pp.111-122
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• 1996

Streptomyces chibaensis J-59 xylanase는 CSL 배지(1% corn steep liquor, 0.15% glucose, 0.1% $MgSO_4{\cdot}7H_2O$, pH 7.0)에서 1% xylan을 효소생산 유도물질로 첨가하였을 경우에 생산(0.83 unit/ml) 되었으나, xylose를 비롯한 각 종 탄소원을 포함하는 배지에서는 효소가 생산되지 않았다. S. chibaensis로 부터 생산된 세포외 xylanase를 $(NH_4)_2SO_4$ 분획침전, DEAE-Sephadex A-50 column chromatography, Sephadex G-200 gel filtration 과정으로 약 29%의 수율로 20배 정제하였다. 정제한 xylanase는 SDS-PAGE 및 Sephadex G-200 gel filtraion에서 분자량이 모두 25,000 Da으로 나타나 monomenc enzyme으로 확인되었다. 금속이온에 대한 영향은 $Fe^{3+}$, $Hg^{2+}$, $Cu^{2+}$, sodium dodecyl sulfate, N-bromosuccinide 등에서는 아주 강한 저해를 받았고, $Mn^{2+}$, $Zn^{2+}$에서는 약간의 저해를 받았다. 반면에 $Mg^{2+}$는 효소활성을 증가시켰다. Xylanase에 의한 xylooligo 당의 생산양상을 TLC로 조사한 결과 xylobiose, xylotriose 및 xylotetrose가 주 생산물이었으며, 반응 1시간 이후부터 소량의 xylose가 생성되었다. 따라서 본 효소는 전형적인 endotype xylanase로 확인되었으며 새로운 기능성식품인 자일로 올리고당(xylooligo-saccharides)의 제조에 이용할 수 있을 것이다.