• 한국잡초학회지
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• 제17권4호
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• pp.345-361
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• 1997

Photoassimilates translocate from regions of carbohydrate synthensis(source) to regions of carbohydrate utilization or storage(sink). In the source, assimilate loads into the phloem for long-distance transport. Current evidence suggests that there are twig loading mechanisms : one involves assimilate transfer via the apoplasm and then load into the phloem by carrier-mediated proton-sucrose cotransport, while the other involves movement through the continuous symplastic connections between the mesophyll cells and the phloem. Inspite of problems associated with the interpretation of experiments, the evidence for apoplastic loading remains convincing because the apoplastic loading systems explains well the observed accumulation capacity arid the selectivity of assimilate uptake by tile phloem.

• 한국환경보건학회지
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• 제36권3호
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• pp.171-181
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• 2010

Semivolatile aerosols exist as vapor and particles at the same time in room temperature and each phase has different intake and uptake mechanisms. This characteristic requires substantial consideration during exposure assessment of semivolatile aerosol. Some sampling methods for solid particles pose high possibility of evaporative loss during sampling. Therefore, when establishing sampling strategy for them, the factors affecting the phase distribution of semivolatile aerosol should be counted including semivolatile aerosol of interest and sampling methods used. Evaluation for phase distributions of semivolatile aerosols is also recommended. Metalworking fluids, pesticides, asphalt fumes, diesel exhaust, and environmental tobacco smoke are common health-related semivolatile aerosols in workplaces.

• Asian Journal of Atmospheric Environment
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• 제6권3호
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• pp.137-146
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• 2012

Poor indoor air quality is now worldwide concern due to its adverse impacts on our health and environment. Moreover, these impacts carry a significant burden to the economy. Various technical approaches (e.g., biological, activated carbon fiber (ACF), photocatlytic oxidation (PCO), etc.) have gained popularity in controlling indoor volatile organic compounds (VOCs). This is because removing indoor VOC sources or increasing ventilation rates is often not feasible or economical. This review provides an overview of the various air purification technologies used widely to improve indoor air quality. Although most of these technologies are very useful to remove indoor VOCs, there is no single fully satisfactory method due to their diversity and presence at the low concentration. To achieve technical innovations and the development of specific testing protocols, one should possess a better knowledge on the mechanisms of substrate uptake at VOC concentrations.

• Mycobiology
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• 제43권3호
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• pp.179-183
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• 2015

Zinc is an essential micronutrient required for many enzymes that play essential roles in a cell. It was estimated that approximately 3% of the total cellular proteins are required for zinc for their functions. Zinc has long been considered as one of the key players in host-pathogen interactions. The host sequesters intracellular zinc by utilizing multiple cellular zinc importers and exporters as a means of nutritional immunity. To overcome extreme zinc limitation within the host environment, pathogenic microbes have successfully evolved a number of mechanisms to secure sufficient concentrations of zinc for their survival and pathogenesis. In this review, we briefly discuss the zinc uptake systems and their regulation in the model fungus Saccharomyces cerevisiae and in major human pathogenic fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus gattii.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.728-744
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• 2024

The presence of hydrogen absorbed by zirconium-based cladding materials during reactor operation can trigger degradation mechanisms and endanger the rod integrity. Ensuring the durability of the rods in extended time-frames like dry storage requires anticipating hydrogen behavior using numerical modeling. In this context, the present paper describes a hydrogen post-processing tool for Falcon - HYPE, a PSI's in-house tool able to calculate hydrogen uptake, transport, thermochemistry, reorientation of hydrides and hydrogen-related failure criteria. The tool extracts all necessary data from a Falcon output file; therefore, it can be considered loosely coupled to Falcon. HYPE has been successfully validated against experimental data and applied to reactor operation and interim storage scenarios to present its capabilities.

• 대한핵의학회지
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• 제34권4호
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• pp.294-302
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• 2000

목적: 종양세포에서 F-18-FDG 섭취 기전을 규명하기 위하여 F-18-FDG 섭취와 포도당운반체-1 (Glut-1), hexokinase의 발현과의 상관관계를 조사하였다. 대상 및 방법: 사람의 대장암(SNU-C2A, SNU-C4, SNU-C5), 간암(SNU-387, SNU-423, SNU-449), 폐암(NCI-H522, NCI-H358, NCI-H1299), 자궁경부암(HeLa, HeLa 229, HeLa S3), 그리고 뇌암(A172, Hs 683)에서 기원한 암 세포주 $5{\times}10^5$ 세포를 24 well plate에 24시간 배양하였다. 여기에 37 kBq의 F-18-FDG를 첨가한 후 각 세포의 섭취 정도를 감마 카운터를 사용하여 측정하였다. Hexokinase의 활성은 분광광도계를 사용하여 측정하였다. 디토콘드리아에서의 hexokinase 활성은 고속원심분리기를 이용하여 미토콘드리아 분획을 분리하여 조사하였다. Glut-1의 발현은 면역조직염색법으로 측정하였다. 결과: 종양세포의 종류에 따라 F-18-FDG 섭취, 전체 그리고 미토콘드리아 hexokinase 활성, 그리고 Glut-1의 발현 정도에 차이가 있었다. 종양세포주에서 F-18-FDG 섭취와 세포전체, 세포내 미토콘드리아 hexokinase 활성과의 상관관계(각각 r=0.27, r=0.26)는 낮게 나타났으며, Glut-1의 발현은 F-18-FDG의 섭취와 상관관계(p=0.81, p=0.0015)가 높았다. 대장암 세포주에서 F-18-FDG 섭취와 hexokinase 활성의 상관관계가 없다는 보고를 토대로 대장암 세포주 결과를 제외했을 경우에 F-18-FDG의 섭취와 세포전체 그리고 세포내 미토콘드리아에서의 hexokinase 활성과는 높은 상관관계(각각 r=0.81, p=0.0027, 그리고 r=0.81, p=0.0049)를 보였다. 결론: Glut-1이나 hexokinase 활성이 사람 종양 세포주에서 F-18-FDG의 섭취를 결정하는 주 요인이며, 종양세포의 종류에 따라 이들의 기여도는 서로 다름을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.88-95
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• 2003

The objective of the present study was to determine the effect of exogenous bovine somatotropin on the mammary function in late lactating crossbred Holstein cows. Twelve 87.5% late lactating Holstein cows, approximately 30 weeks postpartum, were divided into two groups of 6 animals each. Animals in the control group were given sodium bicarbonate buffer by subcutaneous injection, while animals in the treated group were given recombinant bovine somatotropin (bST) by subcutaneous injection with 500 mg of bST (14 day prolonged-release bST). After bST injection, milk yield significantly increased from the control level on day 8 to day 20 (p<0.05) with a concomitant increase in mammary blood flow (p<0.01). An increase in mammary blood flow in response to bST treatment was greater than an increase in milk production. An increased plasma concentration of IGF-I coincided with an increase in mammary blood flow in animals treated with bST. There were no significant changes in the concentration of arterial plasma glucose concentration, the arteriovenous concentration difference (A-V difference) and mammary extraction ratio while the mammary glucose uptake increased when compared to the control group. The concentration of arterial plasma triglyceride decreased throughout the experimental period in animals give bST. The plasma concentration of acetate, and the mammary uptake for acetate significantly increased (p<0.05) after bST treatment. The action of bST did not affect the plasma concentration, A-V difference and extraction ratio across the mammary gland for $\beta$-hydroxybutyrate. The concentrations of milk fat and lactose tended to increase during bST treatment. Milk protein concentration initially increased in the first few days and decreased after bST injection when compared to the pretreated period. The present results indicated that bST could affect the mammary function in late lactating cows by increase in milk yield involving changes in both extra-mammary and intra-mammary mechanisms. The exogenous bST exerted its galactopoietic action through an increase in circulating IGF-I of the late lactating Crossbred Holstein cattle.

• 한국염색가공학회지
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• 제17권2호
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• pp.10-18
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• 2005

Silk fabrics mordanted with $Fe^{2+},\;Ni^{2+},\;and\;Cu^{2+}$ were dyed with the aqueous extract of Cassia tora L. seed which was known to include water soluble colorant kaempferol, one of flavonol compounds. Kaempferol can react with free radicals and chelate transition metal ions, which is thought to catalyze processes leading to the appearance of free radicals and have antioxidant activity. In relation to the coordinating and chelating mechanism of the ions with the silk protein and kaempferol, reasonable conclusions should be made on the colorant uptake and the water fastness of the fabric. The amount of the colorant on the fabric was in the order of $Fe^{2+}>Ni^{2+}>Cu^{2+}$. In case of dyeing through coordinaiton bonds between transition metal ions and silk protein and colorants, it was thought that the ions with the smaller secondary hydration shell, the higher preference to the atoms of the ligand coordinated, and the suitable bonding stability for the substitution of primarily hydrated water molecules for colorants led to the higher colorant uptake. The water fastnsess of the fabric was in the order of $Fe^{2+}>Cu^{2+}>Ni^{2+}$. It should be reasonable to choose transition metal ions with weak and strong tendency to the ionic and the coordination bond, respectively, to the carboxylate anion of the silk protein. Although further research needs to be done, the conclusions above may be generally applied to the natural dyeing through the coordination bond mechanism between transition metal ions and colorants and substrates.

• 동의생리병리학회지
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• 제22권2호
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• pp.340-345
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• 2008

Extract of Acanthopanax senticosus has recently been demonstrated to possess significant antidiabetic potential, in accordance with the traditional use of this plant as an antidiabetic natural health product. The present study evaluated the effects of fermented extract (FE) of this plant on glucose-stimulated insulin secretion, glucose uptake, and streptozotocin-induced type 1 diabetes model. A 3 h pretreatment with FE prevented $IL-1{\beta}$ and $IFN-{\gamma}$ toxicity in isolated rat islets. However, it did not affect insulin-stimulated glucose uptake in C2C12 myotubes. In addition, pretreatment of mice with FE blocked the destruction of streptozotocin-induced islets and the development of type 1 diabetes. FE reduced blood glucose level, increased insulin secretion, and improved glucose tolerance in streptozotocin-treated mice, whereas nonfermented extract (NFE) had moderate effects. Immunohistochemical staining for insulin clearly showed that pretreatment with FE blocked the STZ-induced islets destruction and restored the number of islet cells that secreted insulin to the level of the control. Although the active principles and their mechanisms of action remain to be identified, FE may nevertheless represent a novel complementary therapy and a source of novel therapeutic agents against type 1 diabetes mellitus.

• Journal of Veterinary Science
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• 제23권1호
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• pp.4.1-4.15
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• 2022

Background: Flavonoids are natural polyphenols found widely in citrus fruit and peel that possess anti-adipogenic effects. On the other hand, the detailed mechanisms for the antiadipogenic effects of flavonoids are unclear. Objectives: The present study observed the anti-adipogenic effects of five major citrus flavonoids, including hesperidin (HES), narirutin (NAR), nobiletin (NOB), sinensetin (SIN), and tangeretin (TAN), on AMP-activated protein kinase (AMPK) activation in palmitate (PA)-treated HepG2 cells. Methods: The intracellular lipid accumulation and triglyceride (TG) contents were quantified by Oil-red O staining and TG assay, respectively. The glucose uptake was assessed using 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose (2-NBDG) assay. The levels of AMPK, acetyl-CoA carboxylase (ACC), and glycogen synthase kinase 3 beta (GSK3β) phosphorylation, and levels of sterol regulatory element-binding protein 2 (SREBP-2) and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) expression were analyzed by Western blot analysis. The potential interaction between the flavonoids and the γ-subunit of AMPK was investigated by molecular docking analysis. Results: The flavonoid treatment reduced both intracellular lipid accumulation and TG content in PA-treated HepG2 cells significantly. In addition, the flavonoids showed increased 2-NBDG uptake in an insulin-independent manner in PA-treated HepG2 cells. The flavonoids increased the AMPK, ACC, and GSK3β phosphorylation levels and decreased the SREBP-2 and HMGCR expression levels in PA-treated HepG2 cells. Molecular docking analysis showed that the flavonoids bind to the CBS domains in the regulatory γ-subunit of AMPK with high binding affinities and could serve as potential AMPK activators. Conclusion: The overall results suggest that the anti-adipogenic effect of flavonoids on PA-treated HepG2 cells results from the activation of AMPK by flavonoids.