• Journal of Environmental Science International
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• v.1 no.2
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• pp.49-57
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• 1992

First, We classified man-made lakes in Korea as 4-type lakes, that is, there were River-run lakes, Dendritic lakes, Reservoir-lakes, River-mouth lakes, We studied on the environmental factors of 3-type lakes except River-mouth lakes, compared these lakes with natural lakes in foreign country. Environmental factors were watershed area, lake storage, mean depth, hydraulic retention time. As a results, 3-type lakes in Korea had remarkable differences one another according to above-mentioned environmental factors. First, We recognized that River-run lakes had higher nutrient loading according to having wider watershed area than natural lakes, and had lower algal growth rate according to shorter hydraulic retention time than natural lakes. Dendritic lake had higher nutrient loading than natural lakes, longer retention time than River-run lake. Reservoir-lakes had environmental factors between Dentritic lakes and River-run lakes. Therefore, If this studies had no quantitative results about various factors, We recognized that man-made lakes in korea had different environmental factors as compared with natural lakes, and had clear classification among 3-type lakes.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.1
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• pp.37-41
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• 2001

HPLC separation of ionic samples tends to be more complicated and difficult to understand than that of non-ionic compounds. On the other hand, band spacing is much more easily manipulated for ionic than for neutral samples. Ion-suppression RP-HPLC method was used with organic modifier and aqueous buffer solution. In this work, five mononucleotides of cytidine-5-monophosphate (5-CMP) disodium salt, uridine-5-monophosphate disodium salt (5-UMP), guanosine-5-monophosphate disodium salt (5-GMP), inosine-5-monophosphate disodium salt (5-IMP), and adenosine-5-monophosphate disodium salt (5-AMP) were examined. Acetic acid and sodium phosphate were used as buffers, and methanol as an organic modifier. A new relationship between the retention factor and the buffer concentration at a fixed modifier content (5% of methanol) could be expressed by following: K = (k(sub)-1 + k(sub)0 (k(sub)B/k(sub)S)/(1 + (k(sub)B/k(sub)S) C(sub)B(sup)a), where C(sub)B was the concentration of buffer. Using this relationship, the calculated values closely matched the experimental data. The derived relationship showed that as the buffer concentration increased, the retention factor approached a certain value, and this was buffer dependent.

• Korean Journal of Human Ecology
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• v.21 no.6
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• pp.1173-1184
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• 2012

This study estimates a structural model to examine the causal relationships among web browsing, switching cost, and site retention in the context of apparel shopping website. A total of 499 usable questionnaires were obtained from consumers aged from 20 to 49 years. For data analysis, exploratory factor analysis, confirmatory factor analysis and structural model were used. The result showed that consumer's perceived switching costs consisted of three factors: relationship cost, search cost and benefit loss cost. In estimated structural model, the relationship cost was influenced by leisure browsing; the search cost was influenced by informational browsing and leisure browsing; the benefit loss cost was influenced by leisure browsing. Especially, the leisure browsing was the most highly related to the benefit loss cost, and followed by relationship cost and search cost. However, hedonic browsing was not significantly related the factors of switching costs. The search costs significantly affected customer's intentions for site retention. A managerial implication was discussed for e-retailers in order to develop strategic switching costs in building long-term relationships with web browsers on the apparel shopping websites.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.10
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• pp.1393-1398
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• 2011

Four 4-month old Charolais${\times}$Dorset male sheep (initial liveweight $25.0{\pm}1.1\;kg$), fitted with rumen and abomasal fistulas and nourished by total intragastric infusions, were used to study the relationships between methionine (Met) supply, nitrogen (N) retention and plasma insulin-like growth factor-I (IGF-I). Four graded levels of Met, i.e. 0 g/16 g N, 1.76 g/16 g N, 3.52 g/16 g N and 7.04 g/16 g N, were infused into abomasums as experimental treatments. The sheep and treatments were allocated in a $4{\times}3$ incomplete Latin square design (Yudon square design). The experiment lasted 3 periods and each period was 10 days. Quadratic correlations were found between Met level (x, g/16 g N) and N retention (y, g/d): y = $-0.03x^2$+0.41x+2.62, $r^2$ = 0.66, n = 12, p = 0.008, and between methionine level (x, g/16 g N) and plasma IGF-I concentration (y, ng/ml): y = $0.80x^2$-4.53x+190.24, $r^2$ = 0.51, n = 12, p = 0.009. No significant correlation was found between plasma IGF-I (x, ng/ml) and N retention (y, g/d) (p>0.05). It was concluded that Met level had a significant influence on N retention and plasma IGF-I concentration whereas IGF-I might not be an important mediator in the regulation of N metabolism by Met in growing sheep nourished by total intragastric infusions.

• Journal of Korean society of Dental Hygiene
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• v.20 no.4
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• pp.505-514
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• 2020

Objectives: Although dental hygienists are professional workers, their job retention is short. Therefore, in order to improve job retention, the relationship between professional identity and professional self-concept was analyzed. Methods: From January 1 to April 30, 2020, 155 dental hygienists were examined. For data analysis, multiple regression analysis was conducted to confirm the effects of professional identity and professional self-concept on job retention. Results: The dental hygienist's professional self-concept was significantly higher in the team manager than in the staff, but the professional identity was not significantly different. Dental hygienists' professional identity, professional self-concept, and job retention were all positively correlated (p<0.05). As a factor influencing dental hygienist's job retention, the self-concept of the profession had a significant effect, but the identity of the profession did not. Conclusions: Since the professional self-concept has a positive effect on maintaining the profession of dental hygienists, it is necessary to make efforts to improve the professional self-concept in order to increase the job retention.

• Journal of Korean Clinical Nursing Research
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• v.27 no.1
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• pp.23-34
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• 2021

Purpose: The purpose of this study is to examine the mediating effect of professional quality of life among hospital nurses in the effects of workplace bullying, social support and resilience on retention intention. Methods: A descriptive and cross-sectional study was conducted on 414 hospital nurses who worked for at least two months at a general hospital in the Seoul metropolitan area. The data were analyzed using IBM SPSS 23.0/AMOS 22.0 programs and employed reliability verification, descriptive statistics include frequency analysis, confirmatory factor analysis, structural equation modeling, and bootstrapping. Results: As a result of the study's structural modeling verification, workplace bullying had a negative effect, social support had a positive effect, resilience had a positive effect on professional quality of life, and professional quality of life had a positive effect on retention intention. Also, workplace bullying, social support, and resilience did not directly impact on retention intention. However, the professional quality of life had a complete mediating effect in the relationships between workplace bullying, social support, resilience and retention intention. The study results verified the mediating effect of professional quality of life affecting the retention intention. Conclusion: In order to improve professional quality of life and retention intention, strategies to prevent workplace bullying and promote social support and resilience are needed.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.989-993
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• 2007

A lactose-hydrolyzed milk with low sweetness was developed using nanofiltration. Raw milk was treated with 0.03% ${\beta}$-galactosidase at $4^{\circ}C$ for 24 h to hydrolyze lactose partially. The resultant lactose-hydrolyzed milk containing 0.43% lactose was then concentrated using a nanofiltration membrane to reach concentration factor of 2.13. The concentration factors and coefficients of retention of milk components in nanofiltration were determined. The concentration factor of milk fat was 2.20 which was the highest of the milk components. The coefficient of retention of calcium and riboflavin was 0.96 and 0.76, respectively. However, the coefficient of retention of glucose, galactose, and sodium was 0.21, 0.15, and 0.22, respectively. Raw milk was treated with 0.1% ${\beta}$-galactosidase at $4^{\circ}C$ for 40 h to hydrolyze lactose fully and then concentrated to reach a concentration factor of 1.6 by using nanofiltration. The concentrated milk was reconstituted with water. The lactose-hydrolyzed milk had sweetness similar to milk. The compositional ratios of crude protein, calcium, sodium, and riboflavin of lactose-hydrolyzed nanofiltrated milk to those of raw milk were 99%, 97%, 77%, and 80%, respectively. This study showed that nanofiltration of lactose-hydrolyzed milk to remove galactose and glucose did not cause significant loss of calcium. The lactose-hydrolyzed nanofiltrated milk contained 0.06% lactose and had sweetness similar to milk.

• 대한공업교육학회지
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• v.40 no.1
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• pp.87-104
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• 2015

This study was carried out to evaluate on the job implementation of ITEC(Invention Teacher Education Center)'s in-service teacher training. To accomplish this purpose, teacher's perception on retention, usefulness, utilization, and enhancement were investigated after one year completing in-service teacher training. The populations of this study were 60 teachers completing in-service teacher training of the southeast ITEC. The methods of this study were survey research and qualitative content analysis. The subjects of survey research were 30 teachers and the case analysis objects were 12 epilogues of in-service teacher training. The mean of job implementation of southeast ITEC's in-service teacher training was 4.07 on a five-point scale. Teacher's perception on job implementation sub factors after one year completing in-service teacher training were as follows. The mean of enhancement factor was 4.39, usefulness factor was 4.11, utilization factor was 3.94, and retention factor was 3.82 on a five-point scale. The mean of enhancement factor and usefulness factor were relatively high level as compared with the mean of job implementation and the mean of utilization factor and retention factor were relatively low level as compared with the mean of job implementation. The results of qualitative content analysis about 12 epilogues of in-service teacher training, some significant instances were deducted that representable retention, usefulness, utilization, and enhancement factors directly and indirectly.

• Journal of Gastric Cancer
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• v.21 no.3
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• pp.298-307
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• 2021

Purpose: Delayed gastric emptying usually manifests as gastric food retention. This study aimed to evaluate the incidence of gastric food retention after distal gastrectomy with gastrojejunostomy in gastric cancer patients and identify the risk factors for its development. Materials and Methods: We retrospectively enrolled 245 patients who underwent distal gastrectomy with gastrojejunostomy for gastric cancer at Boramae Medical Center between March 2017 and December 2019. We analyzed the presence of gastric food residue via computed tomography (CT) scans at 3 and 12 months postoperatively and analyzed the risk factors that may influence the development of gastric food retention. Results: CT scans were performed on 235 patients at 3 months and on 217 patients at 12 months postoperatively. In the group that received closure of Petersen's space, the incidence of gastric food retention was significantly low as per the 3- and 12-month postoperative follow-up CT scans (P=0.028 and 0.003, respectively). In addition, hypertension was related to gastric food retention as per the 12-month postoperative follow-up CT scans (P=0.011). No other factors were related to the development of gastric food retention. In the multivariate analysis, non-closure of Petersen's space (hazard ratio [HR], 2.54; 95% confidence interval [CI], 1.20-5.38; P=0.010) was the only significant risk factor for gastric food retention at 3 months postoperatively, while non-closure of Petersen's space (HR, 2.81; 95% CI, 1.40-5.64; P=0.004) and hypertension (HR, 2.30; 95% CI, 1.14-4.63; P=0.020) were both significant risk factors for gastric food retention at 12 months postoperatively. Conclusions: Closure of Petersen's space has an effect on decrease the incidence of gastric food retention after distal gastrectomy with gastrojejunostomy in gastric cancer patients.

• Communications of Mathematical Education
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• v.21 no.2 s.30
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• pp.331-345
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• 2007

This research is aimed to inquiry retention types of middle school students about results of evaluation in school mathematics, For this purpose, we selected evaluation time, problem types, evaluation score, evaluation factors as important factors which influence to students' retention types. Then we classified students' retention types about results of evaluation in school mathematics. From this results, we selected two students as participants, and collected data through depth interviews of them. In depth interviews, we focused on 'what is the core factor influenced to students' evaluation', 'how the core factors reappear in the future'. Through this process, we analyzed middle school students' retention types about results of evaluation in school mathematics.