• Journal of Chest Surgery
• /
• v.31 no.5
• /
• pp.441-450
• /
• 1998

The medullospinal tract cells are known to play an important role in the control of the cardiovascular activities. To clarify the modes of action of the neurotransmitters on these cells, glutamate, GABA(${\gamma}$-aminobutyric acid) and bicuculline were applicated iontophoretically into the rostral ventrolateral medulla in adult cats anesthetised with ${\alpha}$-chloralose. Followings are the results obtained : 1. The spontaneous activities of the cardiac-related neurons in rostral ventrolateral medulla (RVLM) were increased by the glutamate and decreased by the GABA. 2. Bicuculline, an antagonist of GABA, alone didn't increase the frequency of the action potentials, but could reverse the cellular response to the GABA, simultaneously applicated. 3. GABA seemed to decrease the peak as well as the basal discharge of the neurons in RVLM, but hardly changed their periodicities. 4. The cellular responses of RVLM evoked by the peripheral nerve stimulation could be inhibited by the iontophoretically released GABA. In conclusion, GABA seemed to act as an inhibitory neurotransmitter on the cardiac- related neurons in RVLM of the cats anesthetized with ${\alpha}$-chloralose. But the maintenance of the periodicities of these cells after the application of bicuculline suggested that the afferent activity of the baroreceptor didn't play a key role in the spontaneous activities of the RVLM neurons.

• Journal of Food Hygiene and Safety
• /
• v.32 no.2
• /
• pp.89-95
• /
• 2017

A rapid, sensitive analytical method for glucuronolactone in beverages was developed and validated using hydrophilic interaction liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HILIC-ESI-MS/MS). To determine the optimum analytical conditions for glucuronolactone, three different kinds of HILIC columns and two mobile phases with different pH values were examined. An amide-bonded stationary phase with a pH 9 acetonitrile-rich mobile phase was the best condition in terms of column retention, ESI-MS/MS response area, and signal-to-noise ratio. After extraction, glucuronolactone was separated through the HILIC amide column and detected by negative ESI-MS/MS in selected reaction monitoring (SRM) mode. Nine energy drinks sold in Korea were spiked with glucuronolactone at a concentration of 5 ng/mL; the Monster $Energy^{TM}$ sample showed the smallest peak area and its signal-to-noise ratio was used for method validation. Good linearity was obtained in the concentration range from 20 to 1500 ng/mL with a correlation coefficient > 0.998. The developed method had a limit of detection (LOD) of 6 ng/mL and a limit of quantitation (LOQ) of 20 ng/mL. The recovery of this method at concentration of 20, 100, 500, and 1000 ng/mL was 96.3%-99.2% with relative standard deviations (RSD) of 1.6%-14.0%. A reproducibility precision assessment at concentration of 100 and 500 ng/mL was carried out among three laboratories. The recovery of that evaluation was 95.1%-102.3% with RSD of 2.7%-7.0%. An analysis of variance indicated that there was no difference between the recovery results of the three laboratories at the 5% significance level. The validated method is applicable to inspecting beverages adulterated with glucuronolactone in Korea.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.6 no.4
• /
• pp.65-73
• /
• 2002

It has been recognized that the damage control must become a more explicit design consideration. In an effort to develop design methods based on performance it is clear that the evaluation of the nonlinear response is required. The methods available to the design engineer today are nonlinear time history analyses, monotonic static nonlinear analyses, or equivalent static analyses with simulated nonlinear influences. Some building codes propose the capacity spectrum method based on the nonlinear static analysis(pushover analysis) to determine the earthquake-induced demand given by the structure pushover curve. These procedures are conceptually simple but iterative and time consuming with some errors. This paper presents a nonlinear direct spectrum method(NDSM) to evaluate seismic performance of structures, without iterative computations, given by the structural initial elastic period and yield strength from the pushover analysis, especially for MDF(multi degree of freedom) systems. The purpose of this paper is to investigate the accuracy and confidence of this method from a point of view of various earthquakes and unloading stiffness degradation parameters. The conclusions of this study are as follows; 1) NDSM is considered as practical method because the peak deformations of nonlinear system of MDF by NDSM are almost equal to the results of nonlinear time history analysis(NTHA) for various ground motions. 2) When the results of NDSM are compared with those of NTHA. mean of errors is the smallest in case of post-yielding stiffness factor 0.1, static force by MAD(modal adaptive distribution) and unloading stiffness degradation factor 0.2~0.3.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.4
• /
• pp.545-553
• /
• 2021

The frequency by water disaster in urban areas are increasing continuously due to climate change and urbanization. Countermeasures are being conducted to reduce the damage caused by water disasters. An analysis based on permeability, one of the parameters that affect runoff, is needed to predict quantitative runoff in urban watersheds and study runoff reduction. In this study, the SWAT model was simulated for the oncheon stream basin, a representative urban stream in Busan. The permeability map was prepared by calculating the CN values for each hydrologic response unit. Based on the permeability map prepared, EPA SWMM analyzed the effect of LID technology application on the water cycle in the basin for short-term rainfall events. The LID element technology applied to the oncheon stream basin was rooftop greening in the residential complex, and waterproof packaging was installed on the road. The land cover status of the land selected based on the permeability map and the application of LID technology reduced the outflow rate, peak flow rate, and outflow rate and increased the infiltration. Hence, LID technology has a positive effect on the water cycle in an urban basin.

• The Journal of the Korea Contents Association
• /
• v.19 no.1
• /
• pp.293-303
• /
• 2019

The purpose of this research is to investigate the psychological factors affecting job performance of public enterprise employee. Based on the literature review, three types of job performance are identified, which are behavioral responses to the demands from job environment. They are named as task performance, contextual performance, and adaptive performance. As independent variables, four factors were selected form positive psychological concepts, which are self-efficacy, hope, optimism, and resilience. These are the factors which compose of the concept of psychological capital. All the factors are hypothesized to positively affect job performances. From the regression analysis results, all the psychological factors in the model were turned out to have statistically significant impacts on the job performances. The importance of variable 'resilience' were dominant all three models, which might be interpreted as a behavioral response to the demands from uncertain organizational enviornments. From the marginal effect analysis, contextual performance decreases first five years, then reach peak at 20th. year. These results demonstrates that mid-level employees in the organizational hierarchy are more concerned with the overall performance of organization.

• Ecology and Resilient Infrastructure
• /
• v.6 no.1
• /
• pp.23-33
• /
• 2019

Naeseong Stream is a sand-bed river that flows through the northern area of Gyeongbuk province. It is characterized by dynamic sandy bedforms developed in response to the seasonal hydrological fluctuation and by its unique riverine landscape called "white river." However, changes including construction of Yeongju Dam from 2010 and the extensive vegetation establishment around 2015 occurred along the Naeseong Stream. This paper aims to analyze climate, hydrology, and water quality as factors and to examine the possibility of channel changes accordingly. The second least precipitation during the last 60 years happened in 2015, which led to the lowest peak discharge in 50 years. The sediment characteristics of Naeseong Stream were not significantly different along the upstream and downstream reaches, but it was confirmed that annual minimum water level of the stream decreased continuously regardless of the dam construction. This suggests that intermittent drought and change in water quality are likely to provide favorable conditions for riparian vegetation establishment and the resulting physical changes have affected riverbed degradation. Therefore, it is necessary to conduct diversified monitoring in connection with river vegetation change in order to analyze the causes of river changes.

• Science of Emotion and Sensibility
• /
• v.22 no.1
• /
• pp.45-54
• /
• 2019

Empathy has been observed to be pivotal in enhancing both social relations and the efficiency of task performance. Empathetic interaction has been shown to begin with individuals mirroring each other's facial expressions, vocal tone, actions, and so on. The internal responses of the cardiovascular activity of people engaged in empathetic interaction are also known to be synchronized. This study attempted to objectively and quantitatively define the rules of empathy with regard to the synchronization of cardiac rhythm between persons. Seventy-four subjects participated in the investigation and were paired to imitate the facial expressions of their partner. An electrocardiogram (ECG) measurement was taken as the participants conducted the task. Quantitative indicators were extracted from the heart rhythm pattern (HRP) and the heart rhythm coherence (HRC) to determine the difference of synchronization of heart rhythms between two individuals as they pertained to empathy. Statistical significance was confirmed by an independent sample t-test. The HRP and HRC correlation(r) between persons increased significantly with empathy in comparison to an interaction that was not empathetic. A difference of the standard deviation of NN intervals (SDNN) and the dominant peak frequency decreased. Therefore, significant parameters to evaluate empathy have been proposed through a step-wise discrimination analysis. Empathic interactions may thus be managed and monitored for high quality social interaction and communication.

• Animal Bioscience
• /
• v.35 no.2
• /
• pp.184-195
• /
• 2022

Objective: In this study we aimed to evaluate the effect of dietary live yeast supplementation on ruminal pH pattern, fermentation characteristics and associated bacteria in beef cattle. Methods: This work comprised of in vitro and in vivo experiments. In vitro fermentation was conducted by incubating 0%, 0.05%, 0.075%, 0.1%, 0.125%, and 0.15% active dried yeast (Saccharomyces cerevisiae, ADY) with total mixed ration substrate to determine its dose effect. According to in vitro results, 0.1% ADY inclusion level was assigned in in vivo study for continuously monitoring ruminal fermentation characteristics and microbes. Six ruminally cannulated steers were randomly assigned to 2 treatments (Control and ADY supplementation) as two-period crossover design (30-day). Blood samples were harvested before-feeding and rumen fluid was sampled at 0, 3, 6, 9, and 12 h post-feeding on 30 d. Results: After 24 h in vitro fermentation, pH and gas production were increased at 0.1% ADY where ammonia nitrogen and microbial crude protein also displayed lowest and peak values, respectively. Acetate, butyrate and total volatile fatty acids concentrations heightened with increasing ADY doses and plateaued at high levels, while acetate to propionate ratio was decreased accordingly. In in vivo study, ruminal pH was increased with ADY supplementation that also elevated acetate and propionate. Conversely, ADY reduced lactate level by dampening Streptococcus bovis and inducing greater Selenomonas ruminantium and Megasphaera elsdenii populations involved in lactate utilization. The serum urea nitrogen decreased, whereas glucose, albumin and total protein concentrations were increased with ADY supplementation. Conclusion: The results demonstrated dietary ADY improved ruminal fermentation dose-dependently. The ruminal lactate reduction through modification of lactate metabolic bacteria could be an important reason for rumen pH stabilization induced by ADY. ADY supplementation offered a complementary probiotics strategy in improving gluconeogenesis and nitrogen metabolism of beef cattle, potentially resulted from optimized rumen pH and fermentation.

• The Journal of Bigdata
• /
• v.8 no.1
• /
• pp.23-34
• /
• 2023

Nowadays, the Designated Driver Services employ dynamic pricing, which adapts in real-time based on nearby driver availability, service user volume, and current weather conditions during the user's request. The uncertain volatility is the main cause of price increases, leading to customer attrition and service refusal from driver. To make a good Designated Driver Services, development of a demand forecasting model is required. In this study, we propose developing a demand forecasting model using data from the Designated Driver Service by considering normal and peak periods, such as rush hour and rush day, as prior knowledge to enhance the model performance. We propose a new methodology called Time-Series with Conditional Probability(TSCP), which combines conditional probability and time-series models to enhance performance. Extensive experiments have been conducted with real Designated Driver Service data, and the result demonstrated that our method outperforms the existing time-series models such as SARIMA, Prophet. Therefore, our study can be considered for decision-making to facilitate proactive response in Designated Driver Services.

• Analytical Science and Technology
• /
• v.19 no.5
• /
• pp.383-388
• /
• 2006

Simple post-wash method by ion chromatography (IC) was established for the rapid and precise determination of fluoride ion in wastewater from mine in fluorite mineralized area. High sulfate in sample was retained in a pre-column and less strongly held fluoride ion was transferred to the principal separation system using modified conventional IC with switching technique. An analytical column with high capacity (AS 9 HC) was used as a pre-column to retain the amount of high sulfate. A guard column (AG 14) as a separation column was used to increase the response of fluoride and reduce the system pressure. According to the recovery of fluoride ion with one detector and the observation of sulfate peak with another conductivity detector, the optimum switching time of 10-port chromatographic injector was 4.3 min. The limit of detection (S/N = 3) of fluoride in synthetic solution containing $500mg\;L^{-1}$ sulfate was $2.4{\mu}g/L$, with $25{\mu}L$ sample volume.