• 인간식물환경학회지
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• 제23권2호
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• pp.171-178
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• 2020

The present study was conducted to determine the effects of electron beam irradiation on the postharvest quality of cut flowers. Cut flowers were irradiated with electron beam at 100, 200, 400, 600, 800, 1,000, and 2,000 Gy with a 10 MeV linear electron beam accelerator to evaluate their irradiation tolerance. Postharvest quality was determined by monitoring fresh weight loss, flower longevity, flower diameter, flowering rate, visual quality of flowers and leaves, and chlorophyll content. Cut flowers showed a radiation-induced damage with increasing the irradiation dose. Flower longevity and fresh weight of cut flowers decreased when the irradiation dose was increased. Flower bud opening was also inhibited in a dose-dependent manner. The effective irradiation doses for 10% reduction of postharvest quality (ED₁₀) values were 144.4, 451.6, and 841.2 Gy in the 'Medusa' lily, 'Montezuma' carnation, and 'Rosina White' eustoma, respectively. Although tolerance of cut flowers to electron beam irradiation vary according to species, cultivars, or maturity stage conditions, it is conceivable that 'Montezuma' carnation and 'Rosina White' eustoma could be tolerated and maintained overall postharvest quality up to 400 Gy, the generic irradiation dose approved by the Animal and Plant Health Inspection Service (APHIS) and the International Plant Protection Convention (IPPC) for postharvest phytosanitary treatments.

• 한국동물학회지
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• 제14권4호
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• pp.199-204
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• 1971

放射線照射에 의해서 尿 및 血液內에 다량의 deoxycytidine (CdR)이 流出하는 것을 볼수가 있는데, 이것이 DNA의 合成이나 分解와 어떤 관련성이 있으며, 아울러 어느 臟器의 DNA가 放射線感受性이 큰지의 여부를 밝히기 위해서 400R의 X 線을 흰쥐에 全身照射시켜, 간, 지라 및 흉선을 切除하여 均質化시킨 후, CdR-2-$^14 C$을 써서 DNA의 合成率 및 分解率을 測定하였다. DNA의 合成率은 흉선의 경우, 照射후 1 $\\sim$ 3日에 가장 심한 抑制現象이 나타났으며 5日후 부터는 점차 回復됨을 볼 수 있었고, 한편 간과 지라의 경우는 抑制의 정도가 흉선에 비해서 적었으며 回復도 훨씬 빨리 이루어졌다. DNA의 分解率은 지라와 흉선의 경우 비슷하여서 照射후 1日에 영향이 極大로 나타냈으며 回復도 아주 늦게 일어남을 볼 수 있었는데 반해서, 간의 경우는 分解도 덜 일어났으며 回復도 아주 빨리 일어남을 알 수 있었다. 이와 같은 결과는 각종 臟器의 放射線感受性의 차와 再生能의 차에 의해서 나타나는 현상임을 알 수 있고 CdR의 流出量의 增加는 放射線에 의한 DNA合成의 抑制와 DNA分解의 促進의 두가지 요인에 기인하는 것으로 추정되었으며, 전자의 경우는 흉선이, 후자의 경우는 지라와 흉선이 같은 정도의 重要性을 지니고 있음을 알 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6433-6438
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• 2013

In hepatocellular cancer (HCC), lack of response to chemotherapy and radiation treatment can be caused by a loss of epigenetic modifications of cancer cells. Methionine adenosyltransferase 1A is inactivated in HCC and may be stimulated by an epigenetic change involving promoter hypermethylation. Therefore, drugs releasing epigenetic repression have been proposed to reverse this process. We studied the effect of the demethylating reagent 5-aza-2'-deoxycitidine (5-Aza-CdR) on MAT1A gene expression, DNA methylation and S-adenosylmethionine (SAMe) production in the HCC cell line Huh7. We found that MAT1A mRNA and protein expression were activated in Huh7 cells with the treatment of 5-Aza-CdR; the status of promoter hypermethylation was reversed. At the same time, MAT2A mRNA and protein expression was significantly reduced in Huh7 cells treated with 5-Aza-CdR, while SAMe production was significantly induced. However, 5-Aza-CdR showed no effects on MAT2A methylation. Furthermore, 5-Aza-CdR inhibited the growth of Huh7 cells and induced apoptosis and through down-regulation of Bcl-2, up-regulation of Bax and caspase-3. Our observations suggest that 5-Aza-CdR exerts its anti-tumor effects in Huh7 cells through an epigenetic change involving increased expression of the methionine adenosyltransferase 1A gene and induction of S-adenosylmethionine production.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1349-1360
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• 2019

Chronic exposure to ultraviolet (UV) radiation, regarded as a major cause of extrinsic aging or photoaging characterized by wrinkle formation and skin dehydration, exerts adverse effects on skin by causing the overproduction of reactive oxygen species. Agastache rugosa Kuntze, known as Korean mint, possesses a wide spectrum of biological properties including anti-oxidation, anti-inflammation, and anti-atherosclerosis. Previous studies have reported that A. rugosa protected human keratinocytes against UVB irradiation by restoring the anti-oxidant defense system. However, the anti-photoaging effect of A. rugosa extract (ARE) in animal models has not yet been evaluated. ARE was orally administered to hairless mice at doses of 100 or 250 mg/kg/day along with UVB exposure for 12 weeks. ARE histologically improved UVB-induced wrinkle formation, epidermal thickening, erythema, and hyperpigmentation. In addition, ARE recovered skin moisture by improving skin hydration and transepidermal water loss (TEWL). Along with this, ARE increased hyaluronic acid levels by upregulating HA synthase genes. ARE markedly increased the density of collagen and the amounts of hydroxypoline via two pathways. First, ARE significantly downregulated the mRNA expression of matrix metalloproteinases responsible for collagen degradation by inactivating the mitogen-activated protein kinase/activator protein 1 pathway. Second, ARE stimulated the transforming growth factor beta/Smad signaling, consequently raising the mRNA levels of collagen-related genes. In addition, ARE not only increased the mRNA expression of anti-oxidant enzymes but also decreased inflammatory cytokines by blocking the protein expression of nuclear factor kappa B. Collectively, our findings suggest that A. rugosa may be a potential preventive and therapeutic agent for photoaging.

• Radiation Oncology Journal
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• 제9권2호
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• pp.303-310
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• 1991

1990년 1월 22일부터 1991년 7월 31일까지 계명대학교 동산의료원 치료방사선과에 내원한 자궁경부의 편평상피암 환자 19명을 대상으로 방사선치료에 수반되는 조직병리학적 및 초미형태학적 변화를 보기 위해 체외방사선 치료전 후(방사선조사량 900cGy, 1800cGy, 2700cGy, 3600cGy, 4500 cGy)에 조직생검을 시행하여 방사선 치료가 암조직에 미치는 효과, 즉 암세포의 퇴행성 변화에 따른 추이를 관찰하였다. 본 실험을 통하여 방사선 조사가 종양세포에 심한 상해를 미침을 알 수 있었다. 이는 종양세포에 퇴행성 변화를 초래할뿐 아니라 각질의 형태에도 변화를 가져왔다. 방사선에 의한 핵의 퇴행성 변화는 현저하였고 종양의 침윤형태는 변화 없었으나 핵분열수와 종양세포수는 감소하였다. 염증세포의 침윤과 다핵거대세포의 수와 핵용해된 세포의 수는 방사선량이 증가될수록 증가하였다. 전자현미경적으로는 조직에 장세사의 양이 방사선 조사 후 증가하였으나 교소체 수는 감소하였다. 섬유아세포가 2700 cGy 이상에서 나타나기 시작하였고 3600 cGy 이상에서는 종양세포는 급격히 그 수가 감소되고 진행된 섬유화 조직에 의해 대치되었다. 방사선량이 증가함에 따라 활성화된 섬유아세포의 수가 늘어나는 반면 염증세포는 줄어 들었고 간질조직내 교원질이 증가되었다. 미토콘드리아와 내형질 세망의 종창, 세포간교의 소실 및 2차 리소좀의 수는 방사선량이 증가함에 따라 증가되었다.

• Journal of Astronomy and Space Sciences
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• 제36권1호
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• pp.21-33
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• 2019

This paper focuses on the interpretation of radiation fluxes from active galactic nuclei. The advantage of positron annihilation spectroscopy over other methods of spectral diagnostics of active galactic nuclei (therefore AGN) is demonstrated. A relationship between regular and random components in both bolometric and spectral composition of fluxes of quanta and particles generated in AGN is found. We consider their diffuse component separately and also detect radiative feedback after the passage of high-velocity cosmic rays and hard quanta through gas-and-dust aggregates surrounding massive black holes in AGN. The motion of relativistic positrons and electrons in such complex systems produces secondary radiation throughout the whole investigated region of active galactic nuclei in form of cylinder with radius R= 400-1000 pc and height H=200-400 pc, thus causing their visible luminescence across all spectral bands. We obtain radiation and electron energy distribution functions depending on the spatial distribution of the investigated bulk of matter in AGN. Radiation luminescence of the non-central part of AGN is a response to the effects of particles and quanta falling from its center created by atoms, molecules and dust of its diffuse component. The cross-sections for the single-photon annihilation of positrons of different energies with atoms in these active galactic nuclei are determined. For the first time we use the data on the change in chemical composition due to spallation reactions induced by high-energy particles. We establish or define more accurately how the energies of the incident positron, emitted ${\gamma}-quantum$ and recoiling nucleus correlate with the atomic number and weight of the target nucleus. For light elements, we provide detailed tables of all indicated parameters. A new criterion is proposed, based on the use of the ratio of the fluxes of ${\gamma}-quanta$ formed in one- and two-photon annihilation of positrons in a diffuse medium. It is concluded that, as is the case in young supernova remnants, the two-photon annihilation tends to occur in solid-state grains as a result of active loss of kinetic energy of positrons due to ionisation down to thermal energy of free electrons. The single-photon annihilation of positrons manifests itself in the gas component of active galactic nuclei. Such annihilation occurs as interaction between positrons and K-shell electrons; hence, it is suitable for identification of the chemical state of substances comprising the gas component of the investigated media. Specific physical media producing high fluxes of positrons are discussed; it allowed a significant reduction in the number of reaction channels generating positrons. We estimate the brightness distribution in the ${\gamma}-ray$ spectra of the gas-and-dust media through which positron fluxes travel with the energy range similar to that recorded by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) research module. Based on the results of our calculations, we analyse the reasons for such a high power of positrons to penetrate through gas-and-dust aggregates. The energy loss of positrons by ionisation is compared to the production of secondary positrons by high-energy cosmic rays in order to determine the depth of their penetration into gas-and-dust aggregations clustered in active galactic nuclei. The relationship between the energy of ${\gamma}-quanta$ emitted upon the single-photon annihilation and the energy of incident electrons is established. The obtained cross sections for positron interactions with bound electrons of the diffuse component of the non-central, peripheral AGN regions allowed us to obtain new spectroscopic characteristics of the atoms involved in single-photon annihilation.

• The Korean Journal of Physiology and Pharmacology
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• 제14권3호
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• pp.157-161
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• 2010

Heat shock proteins (HSPs) are specifically induced by various forms of stress. Hsp70.1, a member of the hsp70 family is known to play an important role in cytoprotection from stressful insults. However, the functional role of Hsp70 in motor function after spinal cord injury (SCI) is still unclear. To study the role of hsp70.1 in motor recovery following SCI, we assessed locomotor function in hsp70.1 knockout (KO) mice and their wild-type (WT) mice via the Basso, Beattie and Bresnahan (BBB) locomotor rating scale, before and after spinal hemisection at T13 level. We also examined lesion size in the spinal cord using Luxol fast blue/cresyl violet staining. One day after injury, KO and WT mice showed no significant difference in the motor function due to complete paralysis following spinal hemisection. However, when it compared to WT mice, KO mice had significantly delayed and decreased functional outcomes from 4 days up to 21 days after SCI. KO mice also showed significantly greater lesion size in the spinal cord than WT mice showed at 21 days after spinal hemisection. These results suggest that Hsp70 has a protective effect against traumatic SCI and the manipulation of the hsp70.1 gene may help improve the recovery of motor function, thereby enhancing neuroprotection after SCI.

• 한국전자파학회논문지
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• 제20권3호
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• pp.230-239
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• 2009

본 논문에서는 FM 라디오 수신을 위한 RV 차량용 글래스 안테나를 개발하였다. 형상이 간단하면서도 주어진 유리 면적을 효율적으로 이용하여 광대역 정합에 유리하고 높은 수직 편파 이득을 보이는 다중 루프 구조를 사용하였다. 또한, 상용 RV 차량에 장착 시 시야 확보 비율을 높이기 위해서 선로에 유기되는 전류 분포를 기반으로 선로 두께를 조절하여 안테나의 투명도를 향상시켰다. 제안된 안테나는 상용 RV 차량 쿼터 유리에 인쇄하였으며, 반사 손실과 이득 등의 안테나 성능을 반무반사실에서 측정하였다. 제안된 글래스 안테나는 FM 라디오 주파수 대역(80$\sim$110 MHz)에서 안테나 전방향(bore-sight direction: $\theta=90^{\circ}$, $\phi=270^{\circ}$) 평균 이득이 -9.67 dBi로 상용 모노폴 글래스 안테나의 평균 이득 -12.49 dBi와 천장 부착용 마이크로 안테나의 평균 복사 이득 -19.24 dBi 보다 높은 이득을 보였다.

• 한국작물학회지
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• 제63권2호
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• pp.120-130
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• 2018

Improvement in rice grain yield has been approached by means of genetic amendment, cultural management, and environmental adaptation. Subjecting the plant during the grain filling period to an appropriate environment plays a key role in achieving a high grain yield in temperate rice. Field experiments were conducted for two consecutive years with two planting times to assess the relations among grain filling traits, loss of leaf activity during the ripening period, and the grain yield of temperate japonica rice with wide environmental variation. Higher grain yields were attained in 2017 than in 2016 and with late planting than with early planting. The high grain yield accompanied a comparatively lesser increase in grain weight at the early filling stage but more gain in grain weight occurred during the late filling stage. Final grain weight correlated positively with grain filling duration but negatively with grain filling rate. Extended grain filling duration was associated with higher cumulative temperature and cumulative solar radiation for an effective grain filling period. The reduction in SPAD value ${\times}$ leaf dry weight from heading to harvest significantly correlated with final grain dry weight in a positive manner. No significant relation was found between grain filling duration and the decrease in SPAD value ${\times}$ leaf dry weight during the grain filling period. The results suggest that grain filling duration and loss of leaf activity during ripening independently contribute to environmentally induced yield improvement in temperate japonica rice.

• 대한화장품학회지
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• 제18권1호
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• pp.81-98
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• 1992

Hairless mouse에 자외선-B를 일회 조사한 후 시간에 따른 피부보호기능과 표면구조변화의 정도를 TEWL과 주름살밀도로 측정하였다. 자외선-B의 조사 량은 0.5, 1과 3 MED 였으며, 측정 및 관찰은 조사전과 조사 후 1, 3, 5, 7 및 14일에 수행하였다. TEWL은 Evaporimiter로, 주름살밀도는 silicone replica와 image-analyzer를 이용하여 측정하였다. 조사전과 0.5MED 그룹들의 TEWL값은 변화가 없었으나, 1과 3MED그룹들의 TEWL값은 현저한 변화를 보여 3일째에 극대 값을 보였고, 이후 감소하기 시작하여 14일째에는 거의 정상 값에 도달하였다. 반면 주름살밀도는 자외선-B의 조사량에 비례하는 경향을 보여 모든 조사 그룹에서 3-5일째까지 감소한 후 서서히 증가하였다. 결과로부터, 1) 자외선 조사 후 시간에 따른 TEWL과 주름살밀도의 최대, 소 값은 3일째에 나타났으며, 2) 주름살밀도의 회복정도가 조사량에 상관없이 시간에 따라 일정한 기울기를 보였으며, 3) 주름살밀도측정만이 Sub-erythemal 손상의 정도차를 유의하게 보여주었다.