• Phonetics and Speech Sciences
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• v.13 no.3
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• pp.53-64
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• 2021

It is known that the voicing contrast for Japanese word-initial stops is primarily realized as differences in the voice onset time (VOT). However, recent studies have reported that voiced stops are more often produced with a positive VOT than with a negative VOT among the younger generation nationwide. It is also known that post-stop F0 is associated with the stop contrast, but the degree of F0 use differs from region to region. This study explores whether the difference in post-stop F0 functions as a perceptual cue to the stop contrast along with VOT. Fifty-five college students who are native listeners from four different regions participated in two or three perception tests. The results show that VOT is a primary cue to the voiced-voiceless distinction of word-initial stops, but that the effect of post-stop F0 on the stop contrast is marginal. The post-stop F0 is involved in perception only when VOT is ambiguous, such that a sound with high F0 is more often perceived as a voiceless stop, but not vice versa. The results of this study indicate that the acoustic parameters associated with the stop contrast are not the same in production and perception, and suggest that other factors such as context, which is not an acoustic characteristic, may also be involved in the stop contrast.

• The Korean Journal of Oral and Maxillofacial Pathology
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• v.42 no.5
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• pp.111-118
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• 2018

Nicotine of tobacco component has a controversial impact in the clinical outcome of dental implants. Although numerous nicotine effects on bone healing around implants have been presented, it is rarely reported in vitro study about normal human osteoblast(NHost) from oral and maxillofacial area at the surface of implants. The purpose of the present study was to evaluate the effect of nicotine on the proliferation and differentiation response of NHost to plasmatic and salivary levels of nicotine reported in smokers at the surface of screw-type plasma-sprayed titanium implants. NHosts were seeded on the surface of titanium implants and cultured for 21 days in ${\alpha}-MEM$ supplemented with 10% FBS, 50mg/ml ascorbic acid, 5mM ${\beta}$-glycerophosphate and 100nM dexamethasone. Seeded implants were exposed to various nicotine concentration(0.05-0.5mg/ml) from 1 to 21 days, and characterized for cell morphology, proliferation, differentiation, alkaline phosphatase(ALP) activity and ionized calcium concentration(Cai) of medium. Continuous exposure to higher nicotine concentration(above 0.3mg/ml) induced a dose- and time-dependent vacuolation of the cytoplasm, and a tendency to detach from the implant surface. 0.05mg/ml(lower nicotine concentration) did not cause significant effects in the cell proliferation and ALP activity. 0.1-0.2mg/ml caused evident dose-dependent effects in increased cell proliferation, ALP activity and earlier onset of matrix mineralization at levels up to 0.2mg/ml, while a dose-dependent inhibitory effect at 0.3-0.5mg/ml. Cai concentration of control group was decreased at 14 days. Increased Cai concentration at 0.1-0.2mg/ml, decreased Cai concentration at 0.3mg/ml and no change at 0.5mg/ml during the culture period were seen. It suggested that nicotine concentration could paly an role in modulating NHost activity as a contributing factor associated with proliferation and differentiation of NHost at the surface of implants.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.855-865
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• 2018

Sound event detection is one of the research areas to model human auditory cognitive characteristics by recognizing events in an environment with multiple acoustic events and determining the onset and offset time for each event. DCASE, a research group on acoustic scene classification and sound event detection, is proceeding challenges to encourage participation of researchers and to activate sound event detection research. However, the size of the dataset provided by the DCASE Challenge is relatively small compared to ImageNet, which is a representative dataset for visual object recognition, and there are not many open sources for the acoustic dataset. In this study, the sound events that can occur in indoor and outdoor are collected on a larger scale and annotated for dataset construction. Furthermore, to improve the performance of the sound event detection task, we developed a dual CNN structured sound event detection system by adding a supplementary neural network to a convolutional neural network to determine the presence of sound events. Finally, we conducted a comparative experiment with both baseline systems of the DCASE 2016 and 2017.

• Korean Journal of Biological Psychiatry
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• v.28 no.2
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• pp.50-57
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• 2021

Objectives Clozapine is the most effective atypical antipsychotic agent for the treatment-resistant schizophrenia (TRS), however, only 40%-70% of TRS patients respond to clozapine. Moreover, TRS encompasses various symptom dimensions. Therefore, augmentation with other medications for clozapine is frequently applied. However, the prescription pattern of clozapine and combined medications in Korea is yet to be examined. This study aims to investigate the maintenance treatment pattern of clozapine and augmentation agents in one Korean tertiary hospital. Methods The patients with schizophrenia spectrum disorders under clozapine maintenance, defined as one-year clozapine continuation, were subjected for analysis. Medication data at one-year time-point after clozapine initiation was extracted and analyzed. Results Among total 2897 patients having clozapine prescription experience from January 2000 to December 2018, 1011 patients were on clozapine maintenance. The mean age of clozapine initiation was 30.2 ± 11.3 years, and the maintenance dose of clozapine was 217.8 ± 124.3 mg/day. Combination rate of antipsychotics, mood stabilizers, and antidepressants were 43.5%, 25.3%, 38.6%, respectively. Most frequently prescribed drugs in each category were aripiprazole, valproate, and sertraline. Olanzapine equivalent dose of combined antipsychotics was 10.4 ± 7.7 mg/day. Male patients were prescribed higher dose of combined antipsychotics and higher rate of antidepressants. Female patients had later onset of clozapine prescription. Patients with two or more combined antipsychotics were prescribed higher dose of clozapine and higher rate of antidepressants compared to patients with one combined antipsychotic. Conclusions Taken together, among the patients taking clozapine, a substantial rate of patients were under polypharmacy. The present findings based on the real-world prescription pattern could provide the valuable clinical information on the treatment of TRS-related conditions.

• Korean Journal of Cognitive Science
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• v.32 no.3
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• pp.117-139
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• 2021

The way of change detection in which presence of a different item is determined between memory and test arrays with a brief in-between time interval resembles how visual search is done considering that the different item is searched upon the onset of a test array being compared against the items in memory. According to the resemblance, the present study examined whether varying the probability of change occurrence in a visual short-term memory-based change detection task can influence the aspect of response-decision making (i.e., change prevalence effect). The simple-feature change detection task in the study consisted of a set of four colored boxes followed by another set of four colored boxes between which the participants determined presence or absence of a color change from one box to the other. The change prevalence was varied to 20, 50, or 80% in terms of change occurrences in total trials, and their change detection errors, detection sensitivity, and their subsequent RTs were analyzed. The analyses revealed that as the change prevalence increased, false alarms became more frequent while misses became less frequent, along with delayed correct-rejection responses. The observed change prevalence effect looks very similar to the target prevalence effect varying according to probability of target occurrence in visual search tasks, indicating that the background principles deriving these two effects may resemble each other.

• (The)Study of the Eastern Classic
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• no.41
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• pp.477-516
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• 2010

The Korean art history academia has lately been carrying out active research on the Korean art market and art collectors. This area of research is significant in that it attempts to overcome the limitations of previous research trends focused on tracing back and analyzing preeminent masters, their schools and their influence, and approach new subject matters such as art and society, circulation and consumption of art works, which were unapproachable with previous research methods. This paper examines the life, artwork and art collection activities of Songeun(松隱) Yi Byeong-jik(李秉直: 1896-1973), an outstanding painter, calligrapher and art collector during the Japanese colonial period. The primary purpose of this paper is to advance the research project the author has recently initiated on modern Korean art collectors by reconstructing parts of this major art collector's individual lifestyle and to generally identify the art collection activities and the art works that he kept. Yi Byeong-jik, one of the preeminent art collectors during the colonial period, disposed his voluminous collection through two auctions in 1937 and 1941, and then held another auction two weeks before the onset of the Korean War on June 25, 1950 to sell off the remaining works. It seems that the reason why Yi had auctioned off his collections was for the purpose of investing in education. The tale that Yi safely kept 'Sam-guk-yu-sa(三國遺事),' which is considered a national treasure, even through the time of turbulence is evidence of his exemplary behavior as a model art collector. He may be one of the best examples of what an art collector should be in terms of giving back to the society and preserving things of beauty and value. However, one factor that limited and defined Yi's life was that he was a eunuch. This aspect of his life could be pointed out as the biggest factor that stopped him from becoming a mainstream participant in the art world despite his influence as a great painter, calligrapher, significant art collector, and discerning connoisseur.

• Food Science and Industry
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• v.55 no.2
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• pp.154-165
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• 2022

Humans have been breeding the mulberry silkworm for the long period of time to obtain silk fabric and nutrient-rich pupae. Currently, silkworm larvae, pupae, and silk-Fibroin hydrolysates are registered as food raw materials, while silkworm feces and Bombyx batryticatus are registered as Korean traditional medicines. Among sericulture products, individually recognized health functional food ingredients include silk-protein acid-hydrolysates for immunity enhancement, Fibroin-hydrolysates for memory improvement, and freeze-dried 5^th instar and 3^rd-day-silkworm powder for lowering-blood sugar. Recently, HongJam produced by steaming and freeze-drying mature silkworms were reported to have various health-promoting effects such as preventing the onset of Alzheimer's disease and Parkinson's disease, enhancing gastro-intestinal functions, improving skin-whitening and hair growth, and extending healthspan. By consuming silkworm products with various health-promoting effects, it is possible to increase the healthspan of human beings, thereby reducing personal and national medical expenses, resulting in increasing the individual's happiness.

• Animal Bioscience
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• v.35 no.8
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• pp.1223-1234
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• 2022

Objective: The objectives of this study were to evaluate the effects of daily feed intake during the laying period on embryonic myogenic differentiation 1 (MYOD1), myogenic factor 5 (MYF5), and myogenic factor 6 (MYF6) gene expression in genetically fat and lean lines of chickens. Methods: An experiment in a 2×2 factorial design was conducted with two dietary intake levels (100% and 75% of nutrition recommendation) and two broiler chicken lines (fat and lean). Two lines of hens (n = 384 for each line) at 23th week of age were randomly divided into 4 treatments with 12 replicates of 16 birds. The experiment started at 27th week of age (5% egg rate) and ended at 54th week of age. Hatched eggs from the medium laying period were collected. Real time polymerase chain reaction analysis was used to analyse the MYOD1, MYF5, and MYF6 mRNA levels of E7, E9, E11, E13, and E15 body tissues and E17, E19, and E21 chest and thigh muscle samples. Results: The results indicated that there were significant effects of line, dietary intake, and interactions between them on MYOD1, MYF5, and MYF6 gene mRNA expression levels in embryonic tissues. Low daily feed intake did not change the expression trend of MYOD1 mRNA in either line, but changed the peak values, especially in lean line. Low daily feed intake altered the trend in MYF5 mRNA expression level in both lines and apparently delayed its onset. There was no apparent effect of low daily feed intake on the trends of MYF6 mRNA expression levels in either line, but it significantly changed the values on many embryonic days. Conclusion: Maternal nutrient restriction affects myogenesis and is manifested in the expression of embryonic MYOD1, MYF5, and MYF6 genes. Long term selection for fat deposition in broiler chickens changes the pattern and intensity of myogenesis.

• The Journal of the Society of Stroke on Korean Medicine
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• v.18 no.1
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• pp.67-75
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• 2017

■ Objective This is a case report about monocular abducens nerve palsy in a patient with pontine infarction. ■ Method At the time of onset, the patient had eye movement impairment in right eye and diplopia. Brain MRI image showed that there was an infarction in the right pons where the nucleus of abducens nerve is located. There was no obvious improvement in the eye movement before he received Korean medicine treatment. He recieved Korean medicine including acupuncture, electroacupuncture, pharmacoacupuncture and herb medicines for fifty three days. ■ Result After treatment, the movement of right eye was improved to a normal range. The difference in distance from 'center of the pupil' to 'external canthus of the eye' at maximum abducent in both eye changed 0.9cm to 0.1cm at the discharge. In addition, Diplopia was improved at the discharge. ■ Conclusion This case report demonstrated that the Korean medicine treatment is effective to diplopia and eye movement impairment from abducens nerve palsy caused by pontine infarction.

• Tunnel and Underground Space
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• v.33 no.3
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• pp.189-207
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• 2023

In the present study, the thermoshearing experiment on a rough rock fracture were modeled using a three-dimensional grain-based distinct element model (GBDEM). The experiment was conducted by the Korea Institute of Construction Technology to investigate the progressive shear failure of fracture under the influence of thermal stress in a critical stress state. The numerical model employs an assembly of multiple polyhedral grains and their interfaces to represent the rock sample, and calculates the coupled thermo-mechanical behavior of the grains (blocks) and the interfaces (contacts) using 3DEC, a DEM code. The primary focus was on simulating the temperature evolution, generation of thermal stress, and shear and normal displacements of the fracture. Two fracture models, namely the mated fracture model and the unmated fracture model, were constructed based on the degree of surface matedness, and their respective behaviors were compared and analyzed. By leveraging the advantage of the DEM, the contact area between the fracture surfaces was continuously monitored during the simulation, enabling an examination of its influence on shear behavior. The numerical results demonstrated distinct differences depending on the degree of the surface matedness at the initial stage. In the mated fracture model, where the surfaces were in almost full contact, the characteristic stages of peak stress and residual stress commonly observed in shear behavior of natural rock joints were reasonably replicated, despite exhibiting discrepancies with the experimental results. The analysis of contact area variation over time confirmed that our numerical model effectively simulated the abrupt normal dilation and shear slip, stress softening phenomenon, and transition to the residual state that occur during the peak stress stage. The unmated fracture model, which closely resembled the experimental specimen, showed qualitative agreement with the experimental observations, including heat transfer characteristics, the progressive shear failure process induced by heating, and the increase in thermal stress. However, there were some mismatches between the numerical and experimental results regarding the onset of fracture slip and the magnitudes of fracture stress and displacement. This research was conducted as part of DECOVALEX-2023 Task G, and we expect the numerical model to be enhanced through continued collaboration with other research teams and validated in further studies.