• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1305-1310
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• 2012

Breast cancer cells undergo transformation when they spread into surrounding tissues. Studies have shown that cancer cells undergo surface alterations and interact with the surrounding microenvironment during the invasion process. The aim of the present study was to analyse these cancer cell surface alterations and interactions of cancer cells and stroma. Twenty 1-methyl-1-nitrosourea-induced breast cancer samples taken from five rats were fixed in McDowell-Trump fixative and then washed in 0.1 M phosphate buffer. The samples were then treated with osmium tetroxide before being washed in distilled water and subsequently dehydrated through graded ethanols. The dehydrated samples were immersed in hexamethyldisilazane (HMDS), then following removal of excess HMDS, the samples were air dried at room temperature in a dessicator. The dried samples were mounted onto specimen stubs and coated with gold coater before being viewed under a scanning electron microscope. We detected the presence of membrane ruffles on the surface of cancer cells and the formation of unique surface membrane protrusions to enhance movement and adhesion to the surrounding stroma during the process of invasion. Advancing cancer cells demonstrated formation of lamellipodia and invadopodia. The stroma at the advancing edge was desmoplastic with many collagen fibres laid down near the cancer cells. Our data suggest that all of these abnormalities could act as hallmarks of invasiveness for breast cancer.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.157-163
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• 2020

Recently, fine dust has been known to cause cardiovascular diseases here, raising interest in ways to reduce emissions by efficiently using fuel from cars that cause air pollution. Accordingly, a driving assistance system was developed to save fuel by eco-driving and improve the driver's bad driving habits. The system was developed using raspberry pi, arduino and Android. Using RPM, speed, fuel injection information obtained from OBD-II, and gyro-sensor values, Fuel-Cut is induced to create an optimal inertial driving environment. It also provides various information system such as weather, driving environment, and preventing drowsy driving through GUI and voice recognition functions. It is possible to check driving records and vehicle fault information using Android application and has low overhead for message transmission using MQTT protocol optimized for IoT environment.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.4
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• pp.290-299
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• 2016

The most powerful energy resource in nature is solar energy which becomes directly converted to electric power in worldwide. Most of the photovoltaic power plants are commonly installed on sunny side of the ground. Thus the installation of photovoltaic power plant could produce an unexpected adverse effect by sacrificing the productivity from green field or forest. To avoid these adverse effect floating photovoltaic plant has been devised and installed on inland reservoir. The photovoltaic plant could utilize ignored water surface without sacrificing the productivity of the ground. Additionally the photovoltaic efficiency has been reenforced by the cooling effect induced by the circulating air flow from water surface. The floating photovoltaic plant could be furnished solar tracking ability by tilting the system operated with the aid of the ballast system. This report is provided to introduce the design of the floating structure with solar panel which furnished solar tracking ability with the aid of ballast system.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.1
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• pp.1-12
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• 2001

Objective: The present study was done to clarify the effects of nicotine and nicotine tartrate on the mouse oocyte maturation in vitro. Methods: GV (germinal vesicle) oocytes were isolated from Graafian follicle of ovaries with sharp needles under a stereomicroscope from female mouse of ICR strain (4 weeks old). Collected oocytes were cultured for 17 hours at $37^{\circ}C$, 5% $CO_2$ in air and 100% humidified condition in incubator. New MHBS was the basic medium used in which nicotine, nicotine tartrate, and mecamylamine (antagonist of nicotinic acetylcholine receptor) were added depending on the experimental group. GV oocytes were cultured in one of these media. Results: Nicotine ($300{\mu}M{\sim}5mM$) had no effects on GVBD (germinal vesicle breakdown) compared to the control, but increasing concentration of nicotine led to an decrease in the first polar body formation. However, nicotine ($10{\sim}500{\mu}M$) induced GVBD in a dose-dependent manner of GV oocytes in a medium containing dbcAMP. Nicotine tartrate ($50{\mu}M{\sim}5mM$) had no effects on GVBD compared to the control but, increasing concentration of nicotine tartrate led to an decrease in the first polar body formation. Mecamylamine $10{\mu}M$ added to the medium containing nicotine ($300{\mu}M{\sim}5mM$) showed higher percentage of the first polar body formation compared to the nicotine ($300{\mu}M{\sim}5mM$) treatment group. Mecamylamine $10{\mu}M$ added to the medium containing nicotine tartrate ($50{\mu}M{\sim}5mM$) showed higher percentage of the first polar body formation compared to the nicotine tartrate ($50{\mu}M{\sim}5mM$) treatment group. Conclusion: The present study suggest that nicotine and nicotine tartrate have the harmful effects on the meiotic maturation of the mouse oocytes in vitro. However, mecamylamine block harmful effects of nicotine and nictine tartrate.

• Hwankyungkyoyuk
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• v.20 no.3
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• pp.63-75
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• 2007

This paper focused on examining the middle school students' perceptions of characteristics(personal knowledge, human responsibility, impact on personal life, and predicted trend, behavior will) of 10 global and 8 local environmental issues. Subjects(N=516) demonstrated by completing a survey that they perceived the characteristics of issues differently on global and local scales, and to a degree those characteristics are related. First, middle school students' perceptions of global and local environmental issues were above mid-point mainly, and perceptions of local environmental issues were higher than those of global environmental issues. At perceptions of characteristics, They perceived that the personal knowledge of global environmental issues were higher than those of local issues, that the human responsibility effects on global environmental issues more than local environmental issues, that global environmental issues in the future, will be more serious. For each environmental issues, the perception of global warming among the global issues was highest, the perception of yellow dust and air pollution among the local issues was highest. For perceptions of characteristics, behavior will to solve the environmental issues was lower than that of 4 characteristics(personal knowledge, human responsibility, impact on personal life, and predicted trend). Second, there was significant difference of the perceptions of two scale environmental issues for area and sex. It showed that Seoul students' perceptions were higher than Kong-ju students' perceptions according to area, and that girl students' perceptions were higher than boy students' perceptions according to sex. Third, correlations among issues were significant. Especially, it was positive relationship between knowledge and human responsibility, human responsibility and impact on personal human responsibility and predicted trend. Educators and communicators should take into account the perceived characteristics of environmental issues and choose effective information sources and teaching methods to improve students' understanding of human-induced environmental changes.

• Toxicological Research
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• v.22 no.1
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• pp.9-13
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• 2006

Diesel exhausted particles (DEP), a kind of fine particles with aerodynamic diameters less than $2.5{\mu}m$ (PM2.5), is of great concern to human health because they remain in atmosphere for long periods, invade an indoor air environment, and can be breathed most deeply into lung and reached the alveoli because of their small size ($0.1{\sim}0.4\;{\mu}m$ in diameter). Epidemiological and experimental studies suggested that DEP may play an active role in the increased respiratory mortality and morbidity. In addition to their physical characteristics, the chemical components including polyaromatic hydrocarbon (PAH) are regarded as a carcinogen causing pulmonary tumors. PLD plays an important role in cell proliferation with various physiological phenomena and affects other enzymes by activating signal transduction pathway. We investigated the cytotoxic mechanism of DEP on RAW 264.7 cells focusing on the role in activation of PLD. Our results suggested DEP induced PLD activity through a specific signaling pathway involving phospholipase $A_2$, PLC, PKC and $Ca^{2+}$ mobilization.

• Journal of the Korean earth science society
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• v.30 no.5
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• pp.660-670
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• 2009

This study examines the changes of an interdecadal circulation over the Asian continent to find cause of the surface warming in Siberia from 1958 to 2004. According to our study, there is a coherency between a long-term change of sea surface temperature in the Indian Ocean and the rapid increase of air temperature in Siberia since 1976/1977. In this study, we suggest that mean wind field changes induced by the positive sea surface temperature anomalies of the Indian Ocean since 1976/1977 are caused of inter-decadal variations in a large-scale circulation over the Asian continent. It also indicates that the inter-decadal circulation over the Asian continent is accompanied with warm southerly winds near surface, which have significantly contributed to the increase of surface temperature in Siberia. These southerly winds have been one of the most dominant interdecadal variations over the Asian continent since 1976/1977. In addition, we investigated the long-term trend mode of 850 hPa geopotential height data over the Asian continent from the Empirical Orthogonal Function (EOF) analysis for 1958-2004. In result, we found that there was an anomalously high pressure pattern over the Asian continent, it is called 'the Asian High mode'. It is thus suggested that the Asian High mode is another response of interdecadal changes of large-scale circulations over the Asian continent.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5253-5257
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• 2014

Formaldehyde (FA) is an economically important chemical, and has been found to cause various types of toxic damage to the body. Formaldehyde-induced toxic damage involves reactive oxygen species (ROS) that trigger subsequent toxic effects and inflammatory responses, which may increase risk of cancer. Therefore, in the present study, we aimed to investigate the possible toxic mechanism in bone marrow caused by formaldehyde. In accordance with the principle of randomization, the mice were divided into four groups of 6 mice per group. One group was exposed to ambient air and the other three groups were exposed to different concentrations of formaldehyde (20, 40, $80mg/m^3$) for 15 days in the respective inhalation chambers, 2h a day. At the end of the 15-day experimental period, all mice were killed. Bone marrow cells were obtained. Some of those were used for the determination of blood cell numbers, bone marrow karyote numbers, CFU-F, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content; others were used for the determination of mitochondrial membrane potential (MMP), cell cycle and Bcl-2, Bax, CytC protein expression. WBC and PLT numbers in median and high dose groups were obvious reduced, but there was no change on RBC numbers. There was also reduced numbers of bone marrow karyotes and CFU-F in the high dose group. SOD activity was decreased, but MDA content was increased. MMP and Bcl-2 expression were decreased with increasing formaldehyde concentration, while expression of Bax and Cyt C was increased. We also observed change in cell cycling, and found that there was S phase arrest in the high dose group. Our study suggested that a certain concentration of formaldehyde could have toxic effects on the hematopoietic system, with oxidative stress as a critical effect.

• 한국전산유체공학회:학술대회논문집
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• 1996.05a
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• pp.58-67
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• 1996

This paper describes some computational results of various energy and environmental systems using Patankar's SIMPLE method. The specific topics handled in this study are jet bubbling reactor for flue gas desulfurization, cyclone-type afterburner for incineration, 200m tall stack for 500 MW electric power generation, double skin and heat storage systems of building energy saving for the utilization of solar heating, finally turbulent combustion systems with liquid droplet or pulverized coal particle. A control-volume based finite-difference method with the power-law scheme is employed for discretization. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, that is, SIMPLEC. Reynolds stresses are closed using the standard $k-{\varepsilon}$ and RNG $k-{\varepsilon}$ models. Two-phase turbulent combustion of liquid drop or pulverized coal particle is modeled using locally-homogeneous, gas-phase, eddy breakup model. However simple approximate models are incorporated for the modeling of the second phase slip and retardation of ignition without consideration of any detailed particle behavior. Some important results are presented and discussed in a brief note. Especially, in order to make uniform exit flow for the jet bubbling reactor, a well-designed structure of distributor is needed. Further, the aspect ratio in the double skin system appears to be one of important factors to give rise to the visible change of the induced air flow rate. The computational tool employed in this study, in general, appears as a viable method for the design of various engineering system of interest.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.695-701
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• 2013

The suppression of a thermocapillary flow (Marangoni flow) by a nonionic surfactant is experimentally investigated for evaporating pure water droplets on hydrophobic substrates. The experiment shows that as the initial concentration of the surfactant increases, the velocity and lifetime of the flow monotonically decrease. The result confirms the no-slip boundary condition at a liquid-air interface, which is explained on the basis of the previous model regarding the effect of surfactants on the no-slip condition. Interestingly, at an initial concentration much less than a critical value, it is found that depinning of the contact line occurs during the early stage of evaporation, which is ascribed to a reduction in the contact angle hysteresis owing to the presence of the Marangoni flow.