• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.1-8
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• 2007

This study compared the microshear bond strength (${\mu}SBS$) of light-cured and dual-cured composites to enamel bonded with three self-etching adhesives. Crown segments of extracted human molars were cut mesiodistally, and 1 mm thickness of specimen was made. They were assigned to three groups by used adhesives: Xeno group (Xeno III), Adper group (Adper Prompt L-Pop), and AQ group (AQ Bond). Each adhesive was applied to cut enamel surface as per manufacturer's instruction. Light-cured (Filtek Z 250) or dual-cured composite (Luxacore) was bonded to enamel of each specimen using Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to ${\mu}SBS$ testing with a crosshead speed of 1 mm/minute. The mean ${\mu}SBS$ (n = 20 for each group) was statistically compared using two-way ANOVA, Tukey HSD, and t test at the 0.05 probability level, The results of this study were as follows ; 1. The ${\mu}SBS$ of light-cured composite was significantly higher than that of dual-cured composite when same adhesive was applied to enamel. 2. For Z 250, the ${\mu}SBS$ of AQ group ($9.95{\pm}2.51 MPa$) to enamel was significantly higher than that of Adper soup ($6.74{\pm}1.80 MPa$), but not significantly different with Xeno group ($7.73{\pm}2.01 MPa$). 3. For Luxacore, the ${\mu}SBS$ of Xeno group ($5.19{\pm}1.32\;MPa$) to enamel was significantly higher than that of Adper group ($3.41{\pm}1.19\;MPa$), but not significantly different with AQ group ($4.50{\pm}0.96\;MPa$).

• Journal of Intelligence and Information Systems
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• v.22 no.2
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• pp.127-142
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• 2016

Deep learning model is a kind of neural networks that allows multiple hidden layers. There are various deep learning architectures such as convolutional neural networks, deep belief networks and recurrent neural networks. Those have been applied to fields like computer vision, automatic speech recognition, natural language processing, audio recognition and bioinformatics where they have been shown to produce state-of-the-art results on various tasks. Among those architectures, convolutional neural networks and recurrent neural networks are classified as the supervised learning model. And in recent years, those supervised learning models have gained more popularity than unsupervised learning models such as deep belief networks, because supervised learning models have shown fashionable applications in such fields mentioned above. Deep learning models can be trained with backpropagation algorithm. Backpropagation is an abbreviation for "backward propagation of errors" and a common method of training artificial neural networks used in conjunction with an optimization method such as gradient descent. The method calculates the gradient of an error function with respect to all the weights in the network. The gradient is fed to the optimization method which in turn uses it to update the weights, in an attempt to minimize the error function. Convolutional neural networks use a special architecture which is particularly well-adapted to classify images. Using this architecture makes convolutional networks fast to train. This, in turn, helps us train deep, muti-layer networks, which are very good at classifying images. These days, deep convolutional networks are used in most neural networks for image recognition. Convolutional neural networks use three basic ideas: local receptive fields, shared weights, and pooling. By local receptive fields, we mean that each neuron in the first(or any) hidden layer will be connected to a small region of the input(or previous layer's) neurons. Shared weights mean that we're going to use the same weights and bias for each of the local receptive field. This means that all the neurons in the hidden layer detect exactly the same feature, just at different locations in the input image. In addition to the convolutional layers just described, convolutional neural networks also contain pooling layers. Pooling layers are usually used immediately after convolutional layers. What the pooling layers do is to simplify the information in the output from the convolutional layer. Recent convolutional network architectures have 10 to 20 hidden layers and billions of connections between units. Training deep learning networks has taken weeks several years ago, but thanks to progress in GPU and algorithm enhancement, training time has reduced to several hours. Neural networks with time-varying behavior are known as recurrent neural networks or RNNs. A recurrent neural network is a class of artificial neural network where connections between units form a directed cycle. This creates an internal state of the network which allows it to exhibit dynamic temporal behavior. Unlike feedforward neural networks, RNNs can use their internal memory to process arbitrary sequences of inputs. Early RNN models turned out to be very difficult to train, harder even than deep feedforward networks. The reason is the unstable gradient problem such as vanishing gradient and exploding gradient. The gradient can get smaller and smaller as it is propagated back through layers. This makes learning in early layers extremely slow. The problem actually gets worse in RNNs, since gradients aren't just propagated backward through layers, they're propagated backward through time. If the network runs for a long time, that can make the gradient extremely unstable and hard to learn from. It has been possible to incorporate an idea known as long short-term memory units (LSTMs) into RNNs. LSTMs make it much easier to get good results when training RNNs, and many recent papers make use of LSTMs or related ideas.

• Journal of Oral Medicine and Pain
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• v.31 no.1
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• pp.79-89
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• 2006

The aim of this study is to know how the rat submandibular gland changes under various emotional stress condition, using molecular biological methods. Restraint and chronic unpredictable mild stress (CUMS) experiment is conducted on fifty one 7-week old Sprague-Dawley rats (restraint stress experiment: 21, CUMS: 30). The rats were sacrificed, the submandibular glands were excised immediately at certain time, and examined by the use of immunohistochemistry and western blotting. In CUMS experiment, sucrose preference test, water intake change, weight change were implemented at 1 week interval for the experimental period The results are as follows: 1. The number of clusterin-secreting cells of restraint stress group compared to control group showed significantly decreasing tendency in all experimental groups except for the 1st hour group (p<0.001 in the 9th, 24th, 72nd, 120th, and 168th hour group). 2. The number of clusterin-secreting cells of CUMS group compared to control group showed significantly increasing tendency in the 2nd week group (p<0.01), and significantly decreasing tendency in the 4th and 5th week group (p<0.001). 3. Sucrose preference test in CUMS experiment showed significant difference between the 5th week experimental group and control group (p<0.01). 4. Weight change in CUMS experiment showed significant difference between the 5th week experimental group and control group (p<0.01), but water intake change didn't show significant difference compared to control group. 5. In western blot analysis, clusterin expression was decreased on a gradual basis in due time compared to the control group in the restraint stress group. As for CUMS group (chronic unpredictable mild stress group), it was increased till the 2nd week and decreased till the 5th week after that, which is similar to immunohistochemical analysis result and the decreasing tendency of sucrose preference and weigh changes. Through the test, it was proved that expression of clusterin in saliva glands decreases after receiving either acute or chronic stress, indicating relation with depression caused by chronic stress. Unlike other data, however, apoptotic tendency was hardly found in tissues. Diverse possibilities could be suggested on that: first, the stress was not enough to expedite apoptosis; second, apoptosis-related protein was already being secreted though not detected with microscope; third, clusterin, a major secretion molecule of saliva, decreased with saliva's malfunction due to stress. In the respect, it will be necessary to examine proteins expressed in case of cell death or other heat-shock proteins at the same time, in order to see whether any cellular change or death is caused by decreasing clusterin under high stress, and whether the original state is restored as time goes by under mild stress, through longer-term tests using even higher acute stress.

• FLOWER RESEARCH JOURNAL
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• v.17 no.4
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• pp.279-284
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• 2009

In order to recover fertility from sterile interspecific OA-1 $F_1$ hybrid (Oriental hybrid 'Mero Star' ${\times}$ Asiatic hybrid 'Connecticut King'), various concentrations (0.1, 0.3 and 0.5%) of caffeine were injected directly into flower buds and then confirmed the viability of OA-1 $F_1$ hybrid at the flowering time. After the caffeine treatment, fertilized $F_1$ hybrids were crossed as female with Asiatic hybrid 'Lanzarote' as male. Five plantlets were obtained from seven embryos of 16 pollinated flowers at 0.3% treatment of caffeine while 0.5% treatment of caffeine obtained one plant let and 0.1 % treatment of caffeine plantlet did not produce at all. Thus 0.3% of caffeine treatment was considered as optimum concentration to produce subsequent progenies and the OA-l $F_1$ hybrid treated with caffeine produced 51% of putative 2n gametes. Pollen germination of OA-2 ('Romero Star' ${\times}$ 'Lady Rosa') and OA-3 ('Expression' ${\times}$ 'Lady Rosa') was not differ between temperature treatment alone and in combination with caffeine and temperature treatment. In the reciprocal crosses of OA-1 and Asiatic hybrid 'Lanzarote' or Oriental hybrid 'Sorbonne', A ('Lanzarote') ${\times}$ OA-1 or OA-1 ${\times}$ A crosses showed better results than O ('Sorbonne') ${\times}$ OA-1 or OA-1 ${\times}$ a crosses in plant obtaining. All progenies obtained from A ${\times}$ OA-1 or OA-1 ${\times}$ A crosses were confirmed as triploids by GISH analysis.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.179-190
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• 2012

This study was performed to obtain a heat saving effect and enhance the efficiency of a greenhouse by using a hot water piping in order to minimize the operating costs of a greenhouse as oil prices continue to rise. This method also reduces the likelihood of accidents caused by snowdrifts in regions with heavy snowfall. In general, the experimental plot was $2.0{\sim}6.0^{\circ}C$ higher than the control plot. When the skylight felt was opened, the minimum temperature was in the range of $3.0{\sim}12.0^{\circ}C$. Therefore, we judged that damage caused by snowdrifts may be prevented partly by active heating. The temperature difference inside of the greenhouse by height was insignificant. The maximum heating load of the greenhouse according to crop was respectively about $37,000kcal{\cdot}h^{-1}$ and $41,700kcal{\cdot}h^{-1}$. During the experiment, the heat value of each designed temperature in the range of the minimum ambient temperature $-11.9{\sim}4.0^{\circ}C$ was about 95,000~322,000 kcal and it was in the range of $6,050{\sim}20,900kcal{\cdot}h^{-1}$. If it is compared with the maximum heating load, it can be shown that about 15~56% of the heating energy can be supplied. The total heat value and the amount of power consumption were 2,629,025 kcal and 677.3 kWh respectively during the experiment. If it is heated with diesel, a fossil fuel, the consumption during the experiment was 291 L and the cost was 331,700won. Total cost of using electric power was about 24,400 won and it is shown that it is about 7.5% of the cost of diesel consumption. Also, if the total amount of power consumption is converted into energy, it is approximately 582,200 kcal and the energy was just about 22% of the total heat value.

• Korean Journal of Legislative Studies
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• v.22 no.2
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• pp.113-156
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• 2016

Media scholars take a lion stake in power circle. Not only do they take a part in media policies but seize prestigious positions like board members in Korea Communication Commission(KCC). Unfortunately, though, little has been known about who they are, what qualifications they have, and whether they meet public interests. This paper attempts to unveil the mechanism of those politicized intellectuals who are specialized on the media. Two categories divided into 'representative' and 'expertise' are employed for this purpose. On the one hand, the representative means the degree of committment into such public services as participation in conferences or non-profit organizations. On the other hand, the number of research articles, books and projects belong to the expertise. Evaluation levels consist of 'excellence, good and average' were allocated to those scholars who are(were) in 'Power Hole,' where decision makings come into being. Some interesting observations were made though this study. First of all, such criteria as representative and expertise vaguely suggested by the laws were hardly fit into those intellectuals, Rarely did they commit into public service let alone showing vigilance in academic activities. Secondly, both ideological loyalty and political activities in line with the government had much to do with taking such positions. Thirdly, not surprisingly, it showed that to graduate from Seoul National University and have Ph.D. degree from U.S.A. was one of the most essential factors. In final, most of them were very good at taking advantage of the press in way of boosting their publicity. To attend at policy making processes either in form of board members or advisers is inevitable for media experts. However, as shown in this study, such qualification of public service and academic eagerness shouldn't be underestimated. Academic integrity not selling intelligence solely for private interests needs to be protected as well. The authors hope this study to provide a valuable opportunity to establish a kind of ethical standards in participating into politics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.149-162
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• 2000

Coenzyme Q10 is found in all tissues including skin and it is the well-known coenzyme for mitochondrial enzymes. The electron and proton transfer functions of the quinone ring are of fundamental importance for the oxidative phosphorylation pathway to generate energy in the cells. Coenzyme Q10 has been studied as a potent antioxidant molecule in the skin. It is involved in the skin's response to UVR irradiation. The concentration of this antioxidant in UVR exposed skin is higher than in non-exposed skin. However, recent studies have also shown that coenzyme Q10 is one of the first antioxidants to be depleted when skin is UVR-irradiated. This indicates that coenzyme Q10 is primarily involved in defense mechanisms of the skin. Therefore, we questioned whether coenzyme Q10 shows reulatory effect of melanogenesis. Here we report that coenzyme Q10 inhibits melanin neosynthesis of normal human melanocytes grown in culture, and lightens UVB-induced hyperpigmentation of the guinea pig skin in vivo. We treated human melanocytes with 0.05mM to 0.5mM of coenzyme Q10 for a total of two days. This inhibited melanin neosynthesis of cultured human melanocytes dose-dependently. The inhibitory effect of coenzyme Q10 was as effective as kojic acid or vitamin C on cultured human melanocytes. CoQ10 didn't have direct inhibitory effect on tyrosinase activity in in vitro tyrosine hydroxylase activity To further clarify the effect of coenzyme Q10 on the melanogenesis, we established UVB-induced hyperpigmentation on the shaved backs of brownish guinea pigs. The UVB intensity was 500mJ/$\textrm{cm}^2$ and the total energy dose was 1,500 mJ/$\textrm{cm}^2$. The animals were exposed to UVB radiation one times a week for three consecutive weeks. Coenzyme Q10, kojic acid, Arbutin, vitamin C(1% in vehicle) or vehicle alone as a control were then topically applied daily to the hyperpigmented areas twelve times per week far four successive weeks. The lightening effect was evaluated by visual scoring, chromameter and immunohistochemistry. Coenzyme Q10 had lightening effect on the UVB-induced hyperpigmentation without any other side effects, whereas another compounds showed weak lightening efficacies. Therefore, these results suggest that coenzyme Q10 may be useful for solving physiological hyperpigmenting problems for cosmetic purposes.

• The Journal of the Petrological Society of Korea
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• v.23 no.3
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• pp.239-247
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• 2014

The (U-Th)/He dating utilizes the production of alpha particles ($^4He$ atoms) during natural radioactive decays of $^{238}U$, $^{235}U$ and $^{232}Th$. (U-Th)/He age can be determined from the abundances of the parent nuclides $^{238}U$, $^{235}U$ and $^{232}Th$ and the radiogenic $^4He$. Because helium is one of the noble gases (non-reactive) with a relatively small radius, it diffuses rapidly in many geological materials, even at low temperatures. Therefore, ingrowth of $^4He$ during radioactive decay competes with diffusive loss at elevated temperatures during the geologic time scale, determining the amount of $^4He$ existing today in natural samples. For example, He diffusion in apatite is known to be very rapid compared to that in most other minerals, causing a significant diffusive loss at ${\sim}80^{\circ}C$ or higher. At ${\sim}40^{\circ}C$, He diffusion in apatite becomes slow enough to preserve most $^4He$ in the sample. Thus, an apatite's (U-Th)/He age represents the timing when the sample passed through the temperature range of $80-40^{\circ}C$. The crustal depth corresponding to this temperature range is called a "partial retention zone." Normal closure temperatures for a typical grain size and cooling rate are ${\sim}60-70^{\circ}C$ for apatite and ${\sim}200^{\circ}C$ for zircon and titanite. Because the apatite He closure temperature is lower than that of most other thermochronometers, it can provide critical constraints on relatively recent or shallow-crustal exhumation histories.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.383-397
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• 1999

For sites to be investigated, the results of such an investigation can be used in determining foals for cleanup, quantifying risks, determining acceptable and unacceptable risk, and developing cleanup plans t hat do not cause unnecessary delays in the redevelopment and reuse of the property. To do this, it is essential that an appropriately detailed study of the site be performed to identify the cause, nature, and extent of contamination and the possible threats to the environment or to any people living or working nearby through the analysis of samples of soil and soil gas, groundwater, surface water, and sediment. The migration pathways of contaminants also are examined during this phase. Key aspects of cost-effective site assessment to help standardize and accelerate the evaluation of contaminated soils at sites are to provide a simple step-by-step methodology for environmental science/engineering professionals to calculate risk-based, site-specific soil levels for contaminants in soil. Its use may significantly reduce the time it takes to complete soil investigations and cleanup actions at some sites, as well as improve the consistency of these actions across the nation. To achieve the effective site assessment, it requires the criteria for choosing the type of standard and setting the magnitude of the standard come from different sources, depending on many factors including the nature of the contamination. A general scheme for site-specific assessment consists of sequential Phase I, II, and III, which is defined by workplan and soil screening levels. Phase I are conducted to identify and confirm a site's recognized environmental conditions resulting from past actions. If a Phase 1 identifies potential hazardous substances, a Phase II is usually conducted to confirm the absence, or presence and extent, of contamination. Phase II involve the collection and analysis of samples. And Phase III is to remediate the contaminated soils determined by Phase I and Phase II. However, important factors in determining whether a assessment standard is site-specific and suitable are (1) the spatial extent of the sampling and the size of the sample area; (2) the number of samples taken: (3) the strategy of taking samples: and (4) the way the data are analyzed. Although selected methods are recommended, application of quantitative methods is directed by users having prior training or experience for the dynamic site investigation process.

• Journal of Sericultural and Entomological Science
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• v.22 no.1
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• pp.7-25
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• 1980

Some substances and freezing tolerance in the mulberry (Morus species) branch have been studied on the basis of varietal differences and harvesting times along with harvesting methods in autumn. The results obtained are summarized as follows; 1. The highest freezing tolerance was shown in the varieties of Yongcheon-chou, Jasan, Kang-weon No. 3 and Ichihei, the medium in Roso. Kairyonezumigaeshi, Yanagida and Kokuso No. 28, and the lowest in Ichinose, Mokuso, Kokuso No. 21 and Suweousang No. 3. 2. There was a signifiant negative correlation (r= -0.59＊) between death atop percentage in the field and the temperature required to kill 50% of the mulberry buds (T$_{50}$) with the harvesting times and methods in autumn. Cold hardening occurred in the early through the end of September with the peak at the mid-september. During this period, leaf harvest decreased freezing tolerance with remarkable decrease due to picking all the leaves and leaving several leaves at the base of branch. Greater cold hardening was induced by leaving several leaves after topping. 3. Negative correlations were observed between freezing tolerance and the contents of soluble (r =-0.70＊) and crude (r= -0.70＊) protein. However, positive correlations were shown between freezing tolerance and total carbohydrate contents per crude (r=0.31＊) and per soluble (r=0.71＊) protein . There were also positive correlations between freezing tolerance and total sugar (r=0.67＊) and RNA content (r=0.99＊＊). No relationships of dry matter. fat. total carbohydrate and DNA contents were observed to the freezing tolerance. 4. Such sugars as raffinose. lactose, sucrose, glucose, fructose. arabinose. xylose. ribose (assumed) and rhamnose were detected in winter mulberry branch. Major sugars such as sucrose, glucose, and fructose were supposed to have higher relationship to the freezing tolerance than the other sugars. 5. Late harvesting increased RNA content except in the case of total leaf picking at mid-September. Leaf picking decreased RNA content. Some amount of RNA was, however, maintained by leaving several leaves after topping Leaving upper-middle leaves of a branch showed high RNA content. Leaving young leaves at the top and the overmatured leaves at the base showed low content. A positive correlation (r=0.51＊) was noted between RNA content and freezing tolerance in the different harvesting methods.s.