• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.237-245
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• 2011

Asphalt Plug Joint(APJ) is a new type of expansion joint that it's application are increased in USA as well as several European countries. APJ's' advantages are cheap construction and maintenance costs, and simple construction and securing of excellent flatness. However, APJ's usability is hindered because it showed a problem of premature failure. Research for solving this problem has been progressed, and FEM analysis among existing researches was peformed. However, the behavior of APJ was insufficiently analyzed and the reliability of the analysis was much low, since the material showing complicated behavior was oversimplified, Therefore, a material model was proposed and its effectiveness was confirmed by comparing it with actual behavior in order to improve the reliability of FEM analysis in this paper. ABAQUS program was used for FEM analysis, and an elasto-plastic model and a viscous-plastic model as the material model of APJ were suggested on the base of experiment results of APJ material performed by Bramel et al. The elasto-plastic model was defined by time-independent analysis since it didn't consider time and strain rate, and the viscous-plastic model was defined by time-dependent analysis since it considered. Influence of various elements affecting the behavior of APJ was investigated, and it was confirmed that the time-dependent analysis showed better result closed to actual behavior than the time-independent analysis.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.43-50
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• 1998

This study was performed to determine the effects of nitric oxide on human sperm cell function. Semen samples were obtained from normal healthy volunteers. Motile spermatozoas collected by swim-up method were incubated up to 24 hours in Ham's F-10 medium supplemented with a various concentration of sodium nitroprusside (nitric oxide releasing agent). Sperm motility, hyperactivation, acrosome reaction rate, and acrosin activity were determined. The results are as follows; 1. 1mM of SNP resulted in a significant decrease in sperm motility ($44.8%{\pm}8.9%:78.1%{\pm}6.3%$, and hyperactivation $(10.4%{\pm}6.4%:47.7%:{\pm}9.5%)$ after incubation for 3 hours compared with the control group (Ham's F-10 alone), but had no effect on acrosome reaction. 2. At $100{\mu}M$ SNP, sperm motility was reduced after incubation for 6 hours $(54.8%{\pm}3.2%)$ compared with that of the control group $(82.7%{\pm}8.9%)$, but hyperactivation and acrosome reaction were not affected. 3. However, a lower concentration (less than $10{\mu}M$) of SNP had no effect on sperm motility and hyperactivation for 8 hours of incubation but significantly decreased them when incubation periods were increased up to 24 hours compared with the control group. On the other hand, $1{\mu}M$ and $10{\mu}M$ SNP significantly increased the acrosome reaction rate in both acrosomal status ($17.3%{\pm}5.2%$, $23.5%{\pm}4.7%$, respectively) and acrosin activity ($34.3{\mu}IU{\pm}10.5{\mu}IU,\;45.6{\mu}IU{\pm}5.6{\mu}IU$, respectively) as compared with the control group $(7.0%{\pm}4.0%,\;9.5{\mu}IU{\pm}3.4{\mu}IU)$. These results indicate that SNP, NO releasing agent, has a dose-dependent effects on the sperm cell function. Therefore it may positively affect the fertilization by promoting acrosomal reaction at a lower concentration (less than $10{\mu}M$).

• Korean journal of communication and information
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• v.25
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• pp.41-64
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• 2004

This study examined the impact of newspaper scale on the use of local government's news releases by local newspapers. Thus, to see the impact, the four local newspapers and the local government's news releases were content-analyzed. Further, through a depth interview, this study tried to understand local journalists' thoughts on using the news releases published by local government. This study hypothesized a negative relationship between the newspaper scale and the degree of the use of news release, between the scale and the dependent rate on the news releases, and proposed a positive relationship between the scale and the writing styles(neutral, negative, neutral, positive). The research results supported the first two hypotheses, and the third partially. Thus, the greater the newspaper scale, the higher the degree of the use of news release by local newspaper. And the greater the scale, the higher the dependent rate on the news releases. In addition, the smaller newspaper in the scale showed more positive and negative writing styles than the larger did. On the other hand, the larger newspaper tend to have more neutral writing style than the smaller did. The interviewee also indicated, in terms of newspaper scale, there was diverse perspectives on the use of news release.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.91-108
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• 2000

Most of cervical abrasion and erosion lesions show gingival margin where the cavosurface angle is on cementum or dentin. Composite resin restoration of cervical lesion shrink toward enamel margin due to polymerization contraction. This shrinkage has clinical problem such as microleakage and secondary caries. Several methods to diminish contraction stress of composite resin restoration, such as modifying cavity form and building up restorations in several increments have been attempted. The purpose of this study was to compare polymerization contraction stress of composite resin in Class V cavity subjected to cavity forms and placement methods. In this study, finite element model of 5 types of Class V cavity was developed on computer tomogram of maxillary central incisor. The types are : 1) Box cavity 2) Box cavity with incisal bevel 3) V shape cavity 4) V shape cavity with incisal bevel 5) Saucer shape cavity. The placement methods are 1) Incisal first oblique incremental curing 2) Bulk curing. An FEM based program for light activated polymerization is not available. For simulation of curing dynamics, time dependent transient thermal conduction analysis was conducted on each cavity and each placement method. For simulation of polymerization shrinkage, thermal stress analysis was performed with each cavity and each placement method. The time-temperature dependent volume shrinkage rate, elastic modulus, and Poisson's ratio were determined in thermal conduction data. The results were as follows : 1. With all five Class V cavifies, the highest Von Mises stress at the composite-tooth interface occurred at gingival margin. 2. With box cavity, V shape cavity and saucer cavity, Von Mises stress at gingival margin of V shape cavity was lower than the others. And that of box cavity was lower than that of saucer cavity. 3. Preparing bevel at incisal cavosurface margin decreased the rate of stress development in early polymerization stage. 4. Preparing bevel at incisal cavosurface margin of V shape cavity increased the Von Mises stress at gingival margin, but decreased at incisal margin. 5. At incisal margin, stress development by bulk curing method was rapid at early stage. Stress development by first increment of incremental curing method was also rapid but lower than that by bulk curing method, however after second increment curing final stress was the same for two placement methods. 6. At gingival margin, stress development by incremental curing method was suddenly rapid at early stage of second increment curing, but final stress was the same for two placement methods.

• Korean Journal of Remote Sensing
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• v.38 no.6_4
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• pp.1879-1887
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• 2022

In this study, a method of estimating the velocity and altitude of aircrafts photographed in a KOMPSAT-3 satellite was proposed. In the proposed method, parallax effect, which is a time offset between bands due to the photographing method of the KOMPSAT-3 satellite, the structure of the sensor, and the movement of the satellite's orbit, was calculated, and in this process, trucks running on the highway were used. In addition, the actual direction and the direction by parallax effect of the aircraft were calculated using the coordinates of the aircraft in the image, and the attitude information of the KOMPSAT-3 satellite was calculated using metadata to estimate the velocity and altitude of the aircraft. The estimated value through the proposed method was compared with the actual value, automatic dependent surveillance-broadcast (ADS-B), and the error rate was calculated here. As a result, it was confirmed that the velocity and altitude error rate of large aircraft (I1, I3, S2) were lower than that of light aircraft (I2, S2), and the estimated velocity and altitude were relatively high in large aircraft using the proposed method.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.577-582
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• 2022

Credit transactions are used as a means of price discrimination from competitors in order for suppliers to increase customer demand. In particular, in the case of a two-stage supply chain consisting of a supplier, a retailer, and a customer, the deferral of payment for goods allowed by the supplier is a means of reducing the inventory investment cost of the retailer. Retailers have the opportunity to discount the selling price while anticipating an increase in end-customer demand through the reduction of the inventory investment cost. In view of the fact that such trade credit is provided for the purpose of increasing demand as a means of discrimination from competitors, it may be more general that the credit transaction period is allowed flexibly according to the transaction volume. In particular, in the case of deteriorating products, the credit transaction period given according to the order volume is a factor that increases the order volume of the retailer, but product deterioration can be a limiting factor in the increase in the order volume. The deterioration rate actually plays an important role in determining the inventory policy of the retailer. Therefore, in this paper, the effect of such deterioration rate on the inventory policy of retailer is analyzed.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.5
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• pp.313-323
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• 2022

Atrial fibrillation (AF) is the most common supraventricular arrhythmia, and it corresponds highly with exercise intensity. Here, we induced AF in mice using acetylcholine (ACh)-CaCl₂ for 7 days and aimed to determine the appropriate exercise intensity (no, low, moderate, high) to protect against AF by running the mice at different intensities for 4 weeks before the AF induction by ACh-CaCl₂. We examined the AF-induced atrial remodeling using electrocardiogram, patch-clamp, and immunohistochemistry. After the AF induction, heart rate, % increase of heart rate, and heart weight/body weight ratio were significantly higher in all the four AF groups than in the normal control; highest in the high-ex AF and lowest in the low-ex (lower than the no-ex AF), which indicates that low-ex treated the AF. Consistent with these changes, G protein-gated inwardly rectifying K⁺ currents, which were induced by ACh, increased in an exercise intensity-dependent manner and were lower in the low-ex AF than the no-ex AF. The peak level of Ca²⁺ current (at 0 mV) increased also in an exercise intensity-dependent manner and the inactivation time constants were shorter in all AF groups except for the low-ex AF group, in which the time constant was similar to that of the control. Finally, action potential duration was shorter in all the four AF groups than in the normal control; shortest in the high-ex AF and longest in the low-ex AF. Taken together, we conclude that low-intensity exercise protects the heart from AF, whereas high-intensity exercise might exacerbate AF.

• Korean journal of applied entomology
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• v.62 no.4
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• pp.385-388
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• 2023

Gypsy moth (Lymantria dispar), a polyphagous insect pest belonging to the family Lymantriidae, is widely distributed in Korea, Japan, Siberia, Europe, and North America. They pose a threat to various host plants including pear trees, apple trees, and blueberries. Traditionally considered a forest pest, the increasing incursion of gypsy moths into agricultural land near forested areas has intensified damage to crops lacking effective control methods. This study aimed to investigate the temperature-dependent development of gypsy moths to enhance outbreak prediction and advance technology development. The effects of temperature on development of each life stage were investigated under constant temperature conditions of 18, 21, 24, 27, 30, and 33℃ (14L:10D, RH 60±5%) utilizing egg masses collected in Jeollanam-do Jangheung-gun in 2021. The results revealed that higher temperatures accelerated the development rate of the gypsy moth larvae with optimal development occurring at 30℃. However, the survival rate was lowest at 33℃. At the favorable temperature of 30℃, the total development period was 43.8 days for females and 42.5 days for males. The developmental threshold temperature were 13.1℃ for females and 12.5℃ for males, with effective accumulated temperature of 641.1 DD and 657.8 DD, respectively.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.77-83
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• 1996

Effects of insecticide carbofuran and Phenobarbital sodium(PB) or 3-methylcholanthrene(3-MC) on activities of several enzymes in israeli carps were investigated. Survival number of Israeli carp was the same as that of control when PB and 3-MC only was treated, individually and that was low compared to control when carbofuran only was treated. But survival rate of Israeli carp was high compared to individual treatment of carbofuran when combination treatment of carbofuran and PB or 3-MC was carried out. These results indicate that PB and 3-MC can intervene to detoxify carbofuran exposed to israeli carp. In in vivo test for the effect of this chemicals on activity of enzyme in israeli carp, activities of acetylcholinesterase(AChE) and glutathione S-transferase(GST) were inhibited in carbofuran treatment, but did not in combination treatment of carbofuran and P3 or 3-MC. Activities of UDP-glucuronosyltransfe-rase (UDPGT) and cytochrome P-450-dependent monooxygenase increased in individual or combined treatments of carbofuran and PB or 3-MC. These results suggest that a simultaneous application of carbofuran and PB or 3-MC is critical for the enhancement of activity of AChE, GST, UDPGT and monooxygenase and the protection of Israeli carp from carbofuran toxicity.

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.7-20
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• 1995

Taurine, a ${\beta}-amino$ acid, plays an important role as a neuromodulator and is necessary for the normal development of the brain. Since de novo synthesis of taurine in the brain is minimal and in vivo studies suggest that taurine dose not cross the blood-brain barrier, we examined whether the choroid plexus, the blood-cerebrospinal fluid (CSF) barrier, plays a role in taurine transport in the central nervous system. The uptake of $[^3H]-taurine$ into ATP depleted choroid plexus from rabbit was substantially greater in the presence of an inwardly directed $Na^+$ gradient taurine accumulation was negligible. A transient in side-negative potential gradient enhanced the $Na^+-driven$ uptake of taurine into the tissue slices, suggesting that the transport process is electrogenic, $Na^+-driven$ taurine uptake was saturable with an estimated $V_{max}$ of $111\;{\pm}\;20.2\;nmole/g/15\;min$ and a $K_M\;of\;99.8{\pm}29.9\;{\mu}M$. The estimated coupling ratio of $Na^+$ and taurine was $1.80\;{\pm}\;0.122.$ $Na^+-dependent$ taurine uptake was significantly inhibited by ${\beta}-amino$ acids, but not by ${\alpha}-amino$ acids, indicating that the transporter is selective for ${\beta}-amino$ acids. Since it is known that the physiological concentration of taurine in the CSF is lower than that in the plasma, the active transport system we characterized may face the brush border (i.e., CSF facing) side of the choroid plexus and actively transport taurine out of the CSF. Therefore, we examined in vivo elimination of taurine from the CSF in the rat to determine whether elimination kinetics of taurine from the CSF is consistent with the in vitro study. Using a stereotaxic device, cannulaes were placed into the lateral ventricle and the cisterna magna of the rat. Radio-labelled taurine and inulin (a marker of CSF flow) were injected into the lateral ventricle, and the concentrations of the labelled compounds in the CSF were monitored for upto 3 hrs in the cisterna magna. The apparent clearance of taurine from CSF was greater than the estimated CSF flow (p<0.005) indicating that there is a clearance process in addition to the CSF flow. Taurine distribution into the choroid plexus was at least 10 fold higher than that found in other brain areas (e. g., cerebellum, olfactory bulb and cortex). When unlabelled taurine was co-administered with radio-labelled taurine, the apparent clearance of taurine was reduced (p<0.0l), suggesting a saturable disposition of taurine from CSF. Distribution of taurine into the choroid plexus, cerebellum, olfactory bulb and cortex was similarly diminished, indicating that the saturable uptake of taurine into these tissues is responsible for the non-linear disposition. A pharmacokinetic model involving first order elimination and saturable distribution described these data adequately. The Michaelis-Menten rate constant estimated from in vivo elimination study is similar to that obtained in the in vitro uptake experiment. Collectively, our results demonstrate that taurine is transported in the choroid plexus via a $Na^+-dependent,saturable$ and apparently ${\beta}-amino$ acid selective mechanism. This process may be functionally relevant to taurine homeostasis in the brain.