• 제목/요약/키워드: Natural radiation

검색결과 844건 처리시간 0.027초

민들레 추출물의 방사선 방호효과 (Radioprotective Effects of Dandelion(Taraxacum officinale))

  • 최준혁;지태정;민병인
    • 한국콘텐츠학회논문지
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    • 제13권1호
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    • pp.287-293
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    • 2013
  • 민들레는 한방에서 산화방지, 위장 점막 보호 및 담즙 등에 탁월한 효과가 있다고 알려져 있다. 민들레 잎과 뿌리에서 추출한 물질을 SD Rat에 투여한 후 10Gy 방사선 조사 후에 생존율, 혈액변화, 소장조직변화 및 간 조직 변화를 관찰하였다. 관찰결과 민들레 추출물을 투여한 실험군에서 생존율이 4배 이상 높았으며 백혈구, 혈소판 등의 혈액변화에서도 뚜렷한 차이가 보였다. 또한 소장 조직 관찰결과 소장점막세포 소멸 억제 및 소장 점막근판 조직의 염증과 공포가 감소되었다. 따라서 민들레 추출물이 방사선 조사에 따른 혈액구성세포와 소장 조직 손상에 대한 방사선 방호효과를 확인하였다.

Corrosion Charateristics of PEO-treated Ti-6Al-4V Alloy in Solution Containing Si and Mg Ions

  • Park, Seon-Yeong;Choe, Han-Cheol
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2017년도 춘계학술대회 논문집
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    • pp.153-153
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    • 2017
  • The application of the coating supports the mechanical characteristics of the implant, and various materials and coatings are currently being used in the implant in a way to accelerate adhesion. Especially, plasma electrolytic oxidation (PEO) coating has been proposed continually with good surface treatment of titanium alloys. Also, the PEO process can incorporate Ca and P ions on the titanium surface through variables varied factor. PEO process for bioactive surface has carried out in electrolytes containing Ca and P ions. Natural bone is composed of mineral elements such as Mg, Si, Zn, Sr, and Mn, etc. Especially, Mg and Si of these elements play role in bone formation and growth after clinical implantation of bio-implants. In this study, corrosion charateristics of PEO-treated Ti-6Al-4V alloy in solution containing Si and Mg ions has been investigated using several experimental techniques. The PEO-treated surfaces were identified by X-ray diffraction, using a diffractometer (XRD, Philips X' pert PRO, Netherlands) with Cu $K{\alpha}$ radiation. The morphology was observed by field-emission scanning electron microscopy (FE-SEM, Hitachi 4800, Japan) and energy-dispersive X-ray spectroscopy (EDX, Oxford ISIS 310, England). The potentiodynamic polarization and AC impedance tests for electrochemical degradations were carried out in 0.9% NaCl solution at similar body temperature using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV.

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광나무 열매 추출물을 이용한 견직물의 염색성 (Dyeability of Silk Fabrics Using Extracts of Ligustrum Japonicum Thunb Fruit)

  • 이혜선;고성미
    • 한국염색가공학회지
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    • 제22권1호
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    • pp.71-76
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    • 2010
  • In this study the optimum dyeing conditions and blocking effect of UV deodorization efficiency of Ligustrum japonicum Thunb were investigated. Colorants were water-extracted from Ligustrum japonicum Thunb fruit and freeze-drided to obtain colorants powder. The effects of dye concentration, dyeing temperature, dyeing time, and the number of dipping count were studied. Fastness to dry cleaning, rubbing, perspiration, and light were measured according to KS K 0644, KS K 0650, KS K 0715 and KS K 0700, respectively. In order to examine the dyeability according to dyeing conditions, reflectance of fabrics were measured by using UV/VIS spectrophotometer. The bath ratio was 1:20. Dyeing concentration was 100, 200, 300, 400 and 500% on the weight of fiber. Dyeing time was 20, 40, 60, and 80 minutes. Dyeing temperature was 20, 40, 60, 80, and $100^{\circ}C$. The infrared high pressure dying machine was used. As dyeing concentration increased, dye adsorption increased up to 400% and it slowed down. Dye uptake was increased with raising themperature up to $80^{\circ}C$ and it slowed down. Dye adsorption occurred rapidly at first 20 minutes and then it slowed down and reached almost maximum dye uptake at 60 min. Dye uptake increased by repeated dyeing. Therefore, it is considered that optimum dyeing condition is 400%(o.w.f.), $80^{\circ}C$, 60 min. And repeated dyeing improves dye uptake. Color fastness to dry cleaning and rubbing was good, but light fastness and perspiration fastness was not good. Blocking effect of ultraviolet radiation and deodorization efficiency was good.

골괴사를 동반한 만성 방사선 궤양의 치료를 위한 피판술 (Various Flap for Treatment of Radiation Ulcer and Osteoradionecrosis)

  • 윤인식;이원재;정희선;유대현;탁관철
    • Archives of Plastic Surgery
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    • 제35권2호
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    • pp.174-180
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    • 2008
  • Purpose: While radiotherapy remains an essential part of the multidisciplinary treatment of cancers, it may cause unwanted consequences such as tissue break down and chronic non-healing wounds as a result of hypoxia, hypovascularity, and hypocellularity. The conservative treatment of osteoradionecrosis was effective only in the early stages or has a limited result. The surgical treatment of osteoradionecrosis includes various local fasciocutaneous flaps, local myocutaneous flaps and different kinds of free flaps with cancellous bone graft or alloplastic material after removal of all devitalized tissue. This study reviews recent cases of osteoradionecrosis in Severance hospital and investigates the use of various flaps for reconstruction of osteoradionecrosis. Methods: From 2000 to 2006, a total of 29 patients, nine men and twenty women with a mean age of 60.4 years were identified and included in the study. Fasciocutaneous flaps were used on 7 patients and myocutaneous flaps were used on the remaining patients. Mean follow-up period was 10.4 months. Results: In the fasciocutaneous flap group, we noted two complications including total flap failure and a partial flap necrosis. In the myocutaneous flap group, four complications were noted including a partial flap necrosis and 3 cases of wound dehiscence. Considering the complications noted in this study, the natural history of progression to flap necrosis appeared to follow the following sequence of events: marginal flap necrosis, infection, wound dehiscence, flap floating and partial flap necrosis, serially. Conclusion: Successful surgical treatment of osteoradionecrosis includes wide radical debridement and reconstruction with a well vascularized flap like myocutaneous flap or fasciocutaneous flap.

OSL 연대측정을 통한 제주 고산리 유적의 형성과 점유시기 결정 (Evaluation of the formation and occupation of Gosan-ri archaeological site in Jeju Island using OSL dating)

  • 김명진
    • 분석과학
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    • 제29권6호
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    • pp.269-276
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    • 2016
  • 고산리 유적은 우리나라 최초 토기로 알려진 고산리식 토기가 출토된 초기 신석기시대 유적이다. 이 연구에서는 고산리 유적의 형성 및 점유에 대한 절대연대 편년을 위하여 유적 내 표준 퇴적층에서 채취된 시료를 대상으로 OSL 연대측정을 수행하였다. 각 퇴적층의 고고선량은 $220^{\circ}C$ 열전처리 온도의 단일시료재현법을 적용하여 산출되었으며, 최종적으로 유적의 퇴적환경을 고려하여 maximum age model을 적용하여 결정하였다. 산출된 고고선량을 연간선량율로 나누어 고산리 유적 퇴적층의 OSL 연대를 결정하였다. 각 퇴적층의 OSL 연대와 14C 연대를 종합한 결과, 고산리 유적은 신석기인들에 의해 기원전 9천년 이후에 형성된 이후 고산리식 토기를 포함하는 신석기시대 초기 유적에서부터 다양한 시기의 다양한 유구가 존재해 오다가 기원전 4천년 중반에 폐기되어 현재에 이르렀다고 추론된다.

AN ANALYSIS OF INFRARED IMAGES OF JUPITER IMPACTED BY P/SHOEMAKER-LEVY 9

  • KIM YONG HA;SUNG KIYUN;KIM SANG JOON;COCHRAN W. D.;LESTER D. F.;TRAFTON L.;CLARK B. E.
    • 천문학회지
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    • 제29권2호
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    • pp.245-253
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    • 1996
  • We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the $1.5{\mu}m\;NH_3\; band,\;the\;2.3{\mu}m\;CH_4\;band,\;the\;2.12{\mu}m\;H_2\;S(0)$ pressure-induced absorption, and the continua at $1.58{\mu}m\;and\;2.0{\mu}m$ (short K-band). All images except those with the $1.58{\mu}m$ continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about $45^{\circ}$ S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric $CH_4,\;NH_3 \;or\;H_2$. The impact sites observed with the $2.3{\mu}m$ filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and $2.12{\mu}m$ filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about $1\%$. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.

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THE SWINGS EFFECTS OF THE A-X SYSTEM AND v''= 1-0 BAND OF CO

  • KIM SANG-JOON
    • 천문학회지
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    • 제29권2호
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    • pp.223-243
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    • 1996
  • We have constructed a line-by-line model of the A-X system of CO in order to analyze the CO bands appearing in the UV spectra of comets. The model includes electronic, rotational, vibrational transitions, excitations by solar UV radiation, and effects of neutral and electron collisions. The major bands of the A-X system occur in the $1200 - 1800{\AA}$ range where the temporal variation of solar irradiation is significant. The solar spectrum in this spectral range shows many emission lines, which cause a significant Swings effect. We derived fluorescence efficiencies of the bands as functions of heliocentric velocity and cometocentric distance using a high resolution spectrum of the sun. We compared our model with a spectrum of comet P/Halley obtained with the IUE, and estimated that the UV Swings effects are less than 20 fluorescence efficiencies for the most bands of the A-X system. We discuss the temporal variation of solar UV irradiation and its effects on the fluorescence efficiencies. The study of the A-X system also requites knowledge of vibrational and rotational fluorescent processes in the infrared and radio regions because the majority of CO molecules in the coma is in the ground rotational states. The solar infrared spectrum near 5 microns, where the fundamental band of CO occurs, contains strong absorption lines of the fundamental band and hot bands of CO and its isotopes. We derived fluorescence efficiencies of the infrared band as functions of heliocentric velocity and cometrocentric distance. The solar absorption lines near 5 microns cause a 20 reduction of the g-factor of the fundamental band at heliocentric velocities close to 0 km/sec. We discuss the effects of neutral and electron collisions on the fluorescence efficiencies of the infrared and UV bands.

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대두 갈색무늬병에 의한 수량감소의 평가 (Assessment of the Soybean Yield Reduction due to Infection of Septoria Brown Spot, Septoria glycines Hemmi)

  • 오정행;권신한
    • 한국응용곤충학회지
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    • 제22권1호
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    • pp.7-14
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    • 1983
  • 2년간에 걸쳐 조사한 대두의 수량감소는 갈색무늬병을 접종한 경우 농약 살포구에 비해 $15.7-16.4\%$ 감소 차였으며 자연감염의 경우에는 $8.2-9.2\%$의 감소를 나타냈다. 갈색무늬병의 감염은 초장, 주당절수(株當節數), 주당분지수(分枝數)에는 큰 영향이 없었으나 주당협수(狹數)와 종실중(種實重)에는 현저한 감소 현상을 보였다. 대두의 수량감소율을 갈색무늬병의 이병율과 정(正)의 상관을 보였으며 그 상관도는 Van der Plank's infection rate (0.156) 보다는 병 진전국선면적(AUBC) 과의 상관도가 높았다$(r=0.388^*)$. 병진전곡선 면적으로 표시된 갈색무늬병의 감염율과 대두수량 감소율과의 관계는 y=4.38+0.5X $(r=0.686^{**},\;df=25)$으로 나타났다.

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히아루론산을 이용한 조직공학용 Scaffold의 제조와 약물 방출 거동에 관한 연구 (Synthesis of Hyaluronic Acid Scaffold for Tissue Engineering and Evaluation of Its Drug Release Behaviors)

  • 남혜성;김지흥;안정호;정동준
    • 폴리머
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    • 제25권4호
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    • pp.476-485
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    • 2001
  • 본 연구에서는 고분자 지지체를 만든 후 약물을 흡수시켜 방출 특성을 검토하는 기존의 방법에서 나타나는 초기 과다 방출이라는 단점을 보완하고 장기간에 걸친 약물방출이 가능한 고분자 지지체를 구축하기 위해 광반응 관능기를 갖는 히아루론산과 sodium alginate 유도체로 세포의 성장을 촉진하는 약물을 함입한 미립자를 만들고 이를 성형가공한 고분자 지지체를 제작하여 약물 방출 특성을 검토하였다. 이러한 방법으로 만들어진 지지체는 초기 방출이 억제되고 오랜 기간 동안 지속적으로 약물을 서서히 방출하였으며, 뿐만 아니라 천연고분자가 갖는 생체내 분해 특성으로 인하여 일정한 기간 동안 형태를 유지하며 지지체로 기능을 한 이후 분해되어 재생된 조직이 손상조직과 대체 가능하므로, 세포의 성장과 분화를 유도하는 손상조직 대체용 고분자 지지체 본연의 목적을 달성할 수 있을 것으로 기대된다.

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Characteristics of Weather and Climate over the Okhotsk Sea

  • KIM Young Seup;HAN Young Ho;CHEONG Hyeong Bin;DASHKO Nina A.;PESTEREVA Nina M.;VARLAMOV Sergey M.
    • 한국수산과학회지
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    • 제30권6호
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    • pp.974-983
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    • 1997
  • The Okhotsk Sea is unique natural object with climatic peculiarities. The climate of the Okhotsk Sea results from the general distribution of solar radiation during a year, and the characteristics of the atmospheric circulation that varies through a year: In cold half year the main pressure formations are Siberian high and Aleutian low. Asian low centered on Afghanistan dominates over the Asian continent in summer. The North-Pacific sea surface is under effect of permanent North Pacific high. The changes in their position from year to year are very significant. The anticyclonic activity over the Far Eastern Seas is one of the main factors for the formation of weather anomalies over the adjacent territories. The analysis of summer weather characteristics over the coast of Okhotsk and East Sea using the data obtained from Hydrometeorological stations during $1949\~1990$ showed that, to a great extent, distribution of the air temperature depends on thermal state of the Okhotsk Sea and atmospheric circulation over it. We show some relations between weather characteristics and the intensity of atmospheric action center for the North Pacific high in summer when its ridge propagates to Okhotsk Sea. Correlation coefficients between air pressure over the Okhotsk Sea and air temperature for the coastal areas reach up to 0.7. Analysis of the spatial-temporal distribution of main meteorological values over the Okhotsk Sea such as air pressure, and air temperature are also performed.

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