• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.1
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• pp.38-45
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• 2017

Objectives: Radon may be second only to smoking as a cause of lung cancer. Radon is a colorless, tasteless radioactive gas that is formed via the radioactive decay of radium. Therefore, radon levels can build up based on the amount of radium contained in construction materials such as phospho-gypsum board or when ventilation rates are low. This study provides our findings from evaluation of radon gas at facilities and offices in an industrial complex. Methods: We evaluated the office rooms and processes of 12 manufacturing factories from May 14, 2014 to September 23, 2014. Short-term data were measured by using real-time monitoring detectors(Model 1030, Sun Nuclear Co., USA) indoors in the office buildings. The radon measurements were recorded at 30-minute intervals over approximately 48 hours. The limit of detection of this instrument is $3.7Bq/m^3$. Also, long-term data were measured by using ${\alpha}-track$ radon detectors(${\alpha}-track$, Rn-tech Co., Korea) in the office and factory buildings. Our detectors were exposed for over 90 days, resulting in a minimum detectable concentration of $7.4Bq/m^3$. Detectors were placed 150-220 cm above the floor. Results: Radon concentrations averaged $20.6{\pm}17.0Bq/m^3$($3.7-115.8Bq/m^3$) in the overall area. The monthly mean concentration of radon by building materials were in the order of gypsum>concrete>cement. Radon concentrations were measured using ${\alpha}-track$ in parallel with direct-reading radon detectors and the two metric methods for radon monitoring were compared. A t-test for the two sampling methods showed that there is no difference between the average radon concentrations(p<0.05). Most of the office buildings did not have central air-conditioning, but several rooms had window- or ceiling-mounted units. Employees could also open windows. The first, second and third floors were used mainly for office work. Conclusions: Radon levels measured during this assessment in the office rooms of buildings and processes in factories were well below the ICRP reference level of $1,000Bq/m^3$ for workplaces and also below the lower USEPA residential guideline of $148Bq/m^3$. The range of indoor annual effective dose due to radon exposure for workers working in the office and factory buildings was 0.01 to 1.45 mSv/yr. Construction materials such as phospho-gypsum board, concrete and cement were the main emission sources for workers' exposure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.1
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• pp.108-116
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• 2018

Objectives: This study investigated to the analytical work environment, analyst's expert and status of analytical instrument in the designated organization's laboratory for measuring work environment, and carried out to ensure reliability of analytical results. Methods: This study was conducted by 114 analysts who work in designated organization's laboratory for measuring work environment. Information on the working environment and personal characteristics of the analysts were collected using a self-reported questionnaire and were analyzed using the SPSS program through analysis of frequency and t-test. Results: The speciality of subjects was occupational health(57.0%), environmental health(38.6%) and environmental engineering(4.4%), and they had a higher level of academic ability than workers in other industries. Analysts had to handle a large number of sample analysis and many tasks other than analytical work. The analysts answered that it was difficult to analyze organic substances than inorganic substances, and the difficult parts were the analytical methods setting of new substances(55.3%), instrument analysis(24.6%) and principle of analysis(23.7%). Analytical instruments mainly have legally required instruments. The difficulty of the analysis is solved from the senior analyst in the laboratory and analytical information is mainly exchanged through seminar organized by the Association of Occupational Health Analysts. The analysts who are planning to move or considering the company were 48.2%, and the reasons for moving the company were difficult to work(14.0%), low salary(9.6%), employment type(8.8%) and job stress(7.0%). Conclusions: The conclusions of our study were that it was possible to secure reliability by solving the problems such as implementing professional education to improve expertise of analysts, strengthening analytical instruments through institutional improvement and improving work environment.

• Journal of Chitin and Chitosan
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• v.22 no.4
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• pp.254-263
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• 2017

In order to improve the utilization of seaweeds, two kinds of mixed seasoning concentrates (KMS, MKS) were prepared with Kjellmaniella crassifolia and Mytilus coruscus as main ingredients. Fermentation experiments were carried out at $4^{\circ}C$ for 70 days with Kimchi. As a result, SK-A showed a decrease in pH and an increase in acidity. Salinity was not significantly different after 70th day. Reducing sugar content was higher in mixed seasoning group. Lactic acid bacteria Leuconostoc sp. and Lactobacillus sp. Increased in the control group after 20 days of fermentation. The lightness was higher in the control group from the early stage of dipping to 30 days, and the degree of yellowing was higher than that of SK-B group from 20 days. The hardness of the SK-A group was high at the early stage of immersion and at 10th day. The content of aspartic acid and glutamic acid in free amino acid SK-A group was significantly higher (p<0.05). The content of sweet amino acids was significantly higher in the SK-A group on the 0th, 10th, and 30th days of fermentation than the other groups (p<0.05). The sensory test results showed that SK-A showed the most favorable taste. As a result of reviewing the above results, it is expected that SK-A group immersed in 100 g of seasoning liquid KMS made from Kjellmaniella crassifolia and Mytilus coruscus as a subordinate material will provide taste and nutrition to consumers.

• Journal of Life Science
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• v.28 no.11
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• pp.1290-1300
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• 2018

The glucosinolate content, antioxidant activity, and antihypertensive and antidiabetic activities were measured in a crude extract of Dolsan leaf mustard kimchi (DLMK). The glucosinolate content was low at 6.41 and 7.92 mg/g in leaves and stems of DLMK after 21 days of fermentation. The total polyphenol and total flavonoid contents were more than 2 times higher in the leaves (211.7 mg GAE/g, 158.8 mg QE/g) than in the stem (53.7 mg GAE/g, 85.2 mg QE/g) during the fermentation period. The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and electron donating ability (EDA) were similar to those of the control group after 14 days of fermentation, while the ferric reducing antioxidant power (FRAP) was higher in the leaves after 14 days of fermentation when compared to the control group. The angiotensin converting enzyme (ACE) inhibitory activity showed similar or higher inhibitory activity in the leaves when compared to the control group (0.01% captopril), and the ${\alpha}$-glucosidase inhibitory activity was higher in the leaves and stems when compared to the control group (0.05% acarbose). The glucosinolate content and the ABTS, ACE, and ${\alpha}$-glucosidase inhibitory activity were correlated, as determined by the observed straight line plot with a positive grade. During the fermentation period, the detected glucosinolates were sinigrin, glucobrasicin, glucotropeolin, and progoitrin. The DLMK extract is therefore expected to be valuable as a functional food because of its effective antioxidant, antihypertensive, and antidiabetic activities.

• The Korean Journal of Applied Statistics
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• v.36 no.1
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• pp.33-48
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• 2023

In this paper we consider automatic speech recognition (ASR) for Korean speech data in which elderly persons randomly speak a sequence of words such as animals and vegetables for one minute. Most of the speakers are over 60 years old and some of them are dementia patients. The goal is to compare deep-learning based ASR models for such data and to find models with good performance. ASR is a technology that can recognize spoken words and convert them into written text by computers. Recently, many deep-learning models with good performance have been developed for ASR. Training data for such models are mostly composed of the form of sentences. Furthermore, the speakers in the data should be able to pronounce accurately in most cases. However, in our data, most of the speakers are over the age of 60 and often have incorrect pronunciation. Also, it is Korean speech data in which speakers randomly say series of words, not sentences, for one minute. Therefore, pre-trained models based on typical training data may not be suitable for our data, and hence we train deep-learning based ASR models from scratch using our data. We also apply some data augmentation methods due to small data size.

• Journal of Korean Gerontological Nursing
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• v.21 no.2
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• pp.125-134
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• 2019

Purpose: The purpose of this study was to investigate factors related to use of restraints for older adults with dementia in long-term care settings. Methods: This study analyzed secondary data from the Nationwide Survey on Dementia Care in Korea (NaSDeCK). Demographic characteristics, disease characteristics, and functional characteristics were analyzed. Data were analyzed with χ² test, t-test, ANOVA, and logistic regression analysis. Results: Among participants, 8.2% experienced use of restraints. 'Strap' (78.3%) was the most commonly used restraint and 'Behavioral problem' (51.3%) was a major reason for the restraint. Persons who have low levels of daily activity and cognition deficits, higher levels of dependence, histories of falls within the past 3 months, and living in long-term hospitals have greater probability of restraint experience. Conclusion: Developing interventions for older adults who have a high risk of being restrained is essential to minimize unnecessary restraint use among older adults with dementia in long-term care settings. Further study exploring the interacting roles of organizational and staff factors related to use of physical restraints would provide more comprehensive perspectives in understanding this phenomenon.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.25-29
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• 2013

This study was conducted to evaluate the antimicrobial and antioxidant effects of ripened medicinal herb extracts from wood vinegar. The wood vinegar was collected from heated oaks. The Allium sativum (AS), Atractylodes ovate (AO), Cin-namomum zeylanicum (CZ), Coptidis rhizome (CR), Houttuynia cordata (HC), Phellodendron chinense (PC) and Syzygium aromaticum (SA) extracts were collected using wood vinegar, and they were ripened under room temperature for 50 days. All ripened medicinal herb extracts were used to test the antimicrobial and antioxidant activities. For the Lactobacillus, clear zone of 6 different medicinal herb except for CR ranged from 1.28 to 1.63 mm. 3.30 and 3.48 mm of clear zone were determined when CZ and SA were applied to Salmonella and E. coli, respectively (p<0.05), and they showed the largest clear zone as compared to other herbs. The clear zones of CR for Salmonella and E. coli were 2.21 and 3.34 mm, and each clear zone of CR was smaller than that of CZ (p<0.05) but was similar to that of SA (p>0.05). The amount of polyphenol and flavonoid was the highest in SA and CR, and they were 4.28 and 0.38 mg/mL, respectively (p<0.05). The CR shown 0.38 mg/mL flavonoid, had the highest DPPH, and it was 0.41 mM. The DPPH of HZ was significantly lowered in accordance with high amount of polyphenol and flavonoid, 2.56 and 0.20 mg/mL (p<0.05). In conclusion, CZ, SA, and CR showed high antimicrobial and antioxidant potentials, and therefore, may be used as alternatives to antibiotics for poultry diets.

• Sleep Medicine and Psychophysiology
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• v.20 no.1
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• pp.15-21
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• 2013

Objectives: Cognitive impairment in restless legs syndrome (RLS) patients can be affected by sleep deprivation, anxiety and depression, which are common in RLS. The objective of this study is to investigate relationship between cognitive impairment and RLS in the non-medicated Korean elderly with controlling for psychiatric conditions. Method: The study sample for this study comprised 25 non-medicated Korean elderly RLS patients and 50 age-, sex-, and education- matched controls. All subjects were evaluated with comprehensive cognitive function assessment tools- including the Korean version of Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD-K), severe cognitive impairment rating scale (SCIRS), frontal assessment battery (FAB), and clock drawing test (CLOX). Sleep quality and depression were also assessed with Pittsburgh sleep quality index (PSQI) and geriatric depression scale (GDS). Results: PSQI and GDS score showed no difference between RLS and control group. There was no significant difference between two groups in nearly all the cognitive function except in constructional recognition test, in which subjects with RLS showed lower performance than control group (t=-2.384, p=0.02). Subjects with depression ($GDS{\geq}10$) showed significant cognitive impairment compared to control in verbal fluency, Korean version of Mini Mental Status Examination in the CERAD-K (MMSE-KC), word list memory, trail making test, and frontal assessment battery (FAB). In contrast, no difference was observed between subjects who have low sleep quality (PSQI>5) and control group. Conclusions: At the exclusion of the impact of insomnia and depression, cognitive function was found to be relatively preserved in RLS patients compared to control. Impairment of visual recognition in RLS patients can be explained in terms of dopaminergic dysfunction in RLS.

• Journal of Preventive Medicine and Public Health
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• v.32 no.1
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• pp.88-94
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• 1999

Objectives. In order to gain a better understanding of the mechanism of DMF toxicity, recent studies have focused on hepatic drug metabolizing enzymes. In this study, we investigated the effects of DMF on the induction of P450 and the activities of other related enzymes in rat liver microsomes. Methods. DMF was administered to male Sprague Daweley rats by intraperitoneal injection at 0(control), 450(D1), 900(D2), 1,800(D3) mg DMF/kg body weight in olive oil once a day for three days. Hepatic P450 was measured by method of Omura and Sato. We evaluated selective assays for the three drug metabolizing cytochrome P450 isoenzymes 1A1, 2B1 and 2E1. Results. The content of microsomal protein, P450 and b5 were tended to be decreased in DMF treated group, but they were not statistically significant. The activity of NADPH-cytochrome P450 reductase was significantly increased dose dependently(p<0.01), but the activity of NADH-b5 reductase was decreased in the treated group(p<0.01). The activities of PROD and EROD were not significant between control and treated group. The activities of pNPH in the DMF treated groups were higher than that of the control group(p<0.01). When Western immunoblottings were carried out utilizing three monoclonal antibodies which were specific against P4501A1/1, P4502B1/2 and P4502E1, the strong density band corresponding to P4502E1 was observed with the microsomes obtained from the rats treated with DMF. But there were no significant increased in the P4501A1/2 and P4502B1/2 band densities in immunoblotting. Conclusions. These result suggested that P4502E1 was inducible by DMF and P4502E1 isozyme might be responsible for the hydroxylation of DMF to HMMF.

• Korean Journal of Psychosomatic Medicine
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• v.25 no.2
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• pp.210-217
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• 2017

Objectives : Although the Attention Network Test(ANT) has been widely used to assess selective attention including alerting, orienting, and conflict processing, data on its test-retest reliability are lacking for clinical population. The objective of the current study was to investigate test-retest reliability of the ANT in healthy controls and patients with schizophrenia. Methods : Fourteen patients with schizophrenia and 23 healthy controls participated in the study. They are tested with ANT twice with 1 week interval. Test-retest reliability was analyzed with Pearson and Intra-class correlations. Results : Patients with schizophrenia showed high test-retest correlations for mean reaction time, orienting effect, and conflict effect. Also, they showed moderate to high test-retest correlations for mean accuracy and moderate test-retest correlations for alerting effect and conflict error rate. On the other hand, healthy controls revealed high test-retest correlations for mean reaction time and moderate to high test-retest correlations for conflict error rate. In addition, they revealed moderate test-retest correlations for alert effect, orienting effect, and conflict effect. Conclusions : The mean reaction time, alerting effect, orienting effect, conflict effect, and conflict error rate of ANT showed acceptable test-retest reliabilities in healthy controls as well as patient with schizophrenia. Therefore, the analyses of these reliable measures of ANT are recommended for case-control studies in patients with schizophrenia.