• Asian Pacific Journal of Cancer Prevention
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• v.15 no.14
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• pp.5607-5609
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• 2014

Introduction: Although continuing education is necessary for practicing nurses, it is very difficult to organize traditional classes because of large numbers of nurses and working shifts. Considering the increasing development of mobile electronic learning, we carried out a study to compare effects of the traditional face to face method with mobile learning delivered as text messages by cell phone. Materials and Methods: Sixty female nurses working in our hospital were randomly divided into class and short message service (SMS) groups. Lessons concerning breast cancer screening were prepared as 54 messages and sent in 17 days for the SMS group, while the class group participated in a class held by a university lecturer of breast and cancer surgery. Pre- and post-tests were undertaken for both groups at the same time; a retention test also was performed one month later. For statistical analysis, the paired T test and the independent sample T test were used with SPSS software version 16; p<0.05 was considered significant. Results: Mean age and mean work experience of participants in class and SMS groups was $35.8{\pm}7.2$, $9.8{\pm}6.7$, $35.4{\pm}7.3$, and $11.5{\pm}8.5$, respectively. There was a significant increase in mean score post-tests (compared with pretests) in both groups (p<0.05). Although a better improvement in scores of retention tests was demonstrated in the SMS group, the mean subtraction value of the post- and pretests as well as retention- and pretests showed no significant difference between the 2 groups (p=0.3 and p =0.2, respectively). Conclusions: Our study shows that teaching via SMS may probably replace traditional face to face teaching for continuing education in working nurses. Larger studies are suggested to confirm this.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.6
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• pp.732-738
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• 1998

Three crossbred gilts weighing $61{\pm}2kg$ ($mean{\pm}SD$) and three gilts weighing $52{\pm}3kg $ on the day before the first treatment began (d -1) were used for each of two experiments (Exp. 1 and Exp. 2), respectively. In Exp. 1, all pigs were fed the experimental diet (CP 19%) from d -7 to the end of study (d 21) to verify that nitrogen retention is constant during the 21 -d period. In Exp. 2, pigs were fed the control diet (CP 15.5 %) from d -7 to d 8 and then the low-lysine diet from d 9 to d 16 in order to determine how rapidly dietary changes in amino acid composition results in a new equilibrium for nitrogen metabolism. The amount of urine nitrogen loss was not different over 21 days (p > 0.10). Rates of nitrogen retention were not different among pigs (p > 0.10) nor over time (p > 0.10). Average nitrogen retention during the period was 1.00 g/kg $BW^{0.75}$ per day. The apparent biological value was 41%, which did not change over the 3-week period (p > 0.10). The overall efficiency of nitrogen use for nitrogen retention was 35% (Exp. 1). The amount of nitrogen loss in urine and the efficiency of nitrogen utilization for nitrogen gain reached a new equilibrium within 2 to 3 d after the diet was changed. The low-lysine diet resulted in a 20% increase of nitrogen loss in urine (p < 0.001) and a 9% decline in efficiency of nitrogen use for nitrogen retention (p < 0.001). Nitrogen retention while the pigs were fed the control diet was also higher than the retention when pigs were fed the low lysine diet (p < 0.001). The efficiency of nitrogen use for nitrogen retention in pigs fed the control diet was 57% (Exp. 2), which was higher (p < 0.001) than that from pigs fed the low-lysine diets (52%).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.458-462
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• 2003

This study was to survey proper condition of nitrate removal by hydraulic retention time (HRT) and measured growth of black rockfish (Sebastes schlegeli) and giant croaker (Nibea japonica) in the seawater recirculating culture system designed for nitrate removal. Nitrate conversion to nitrogen at 8 hr-HRT was higher than 16 hr-HRT, amounting to $32.2\;g/m^3/day$ in the seawater recirculating culture system. The removal efficiency of nitrate improved when dissolved oxygen was situated less than 0.5 mg/L. Daily growth rate (DGR) and feed efficiency (FE) of S. schlegeli with mean body weight of 108 g in 8 hr-HRT were significantly higher values than those in 4 hr-HRT (P<0.05). The DGR and FE of N. japonica with mean body weight of 12 g in added carbon system showed not differing in the values from N. japonica in control system (P>0.05).

• The korean journal of orthodontics
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• v.52 no.3
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• pp.201-209
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• 2022

Objective: To compare the removal torque of microimplants upon post-use removal and post-retention removal and to assess the influencing factors. Methods: The sample group included 241 patients (age, 30.25 ± 12.2 years) with 568 microimplants. They were divided into the post-use (microimplants removed immediately after use or treatment) and post-retention (microimplants removed during the retention period) removal groups. The removal torque in both groups was assessed according to sex, age, placement site and method, and microimplant size. Pearson correlation and multiple linear regression analyses were performed for evaluating variables influencing the removal torque. Results: The mean period of total in-bone stay of microimplants in the post-retention removal group (1,237 days) was approximately two times longer than that in the post-use removal group (656.28 days). The removal torques in the post-retention removal group (range, 4-5 N cm) were also higher than those in the post-use removal group. The mandible and pre-drilling groups demonstrated higher placement and removal torques than did the maxilla and no-drilling groups, respectively. In the no-drilling post-use removal group, the placement torque and microimplant length positively correlated with the removal torque. In the post-retention removal group, unloading in-bone stay period and microimplant diameter positively correlated with the removal torque in the no-drilling and pre-drilling methods, respectively. Conclusions: The removal torques differed according to the orthodontic loading and removal time of microimplants. With prolonged retention of microimplants inserted using the no-drilling method, the removal torque was clinically acceptable and positively correlated with the unloading in-bone stay period.

• Korean Journal of Occupational Health Nursing
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• v.6 no.1
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• pp.53-71
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• 1997

Across sectional study was performed to evaluate the chronic effects on central nerve system(CNS) of cumulative exposure of complex organic solvents, using neurobehavioral test. Subjects were 66 (male) dock yard painters of some large ship industry which is located in Ulsan. The neurobehavioral test battery used in this study was NCTB (Neurabehavioral Core Test Battery recommended by WHO(World Health Organization), which consisted of 7 items-Profile of mood states (POMS), Simple reaction time, Santa Ana dexterity test. Digit span, Digit symbol, Benton visual retention test and Pursuit aiming. The subjects were classified by 3 groups according to duration of employment(group 1 ; less than 9 years, group 2 ; 10-14 years, group 3 ; more than 15 years). The results of performance were analyzed considering of work duration, age, educational level, alcohol drinking, smoking and testing time as confounding factors. Benton visual retention test, pursuit aiming correct dot and sum of dot showed significant differences among the groups, and decreased with increasing work duration. It indicated that the mean scores of performance ability were lowering according to work duration. Besides, the tests that didn't show statistical significances but showed linear trends were depression-dejection, vigor, fatigue of POMS, slowest time of simple reaction time and digit span forward. Most of the neurobehavioral test items were correlated with age and educational level. After controlling of confounding factors-age and educational level, the results followed ; digit span backward was different significantly. Tension-anxiety, depression-dejection, anger-hostility of POMS, SD and slowest time of simple reaction time, Santa Ana dexterity test non-preferred hand, digit span forward, Benton visual retention test and pursuit aiming correct dot decreased with increasing of work duration. The correlation analysis was done in order to find out the relationship between subjective symptom and the scores of neurobehavioral core test battery. According to the results of analysis there were no items that had statistical significant relationship(p<0.05).

• The korean journal of orthodontics
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• v.27 no.1
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• pp.55-63
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• 1997

The purpose of thus study was to measure the changes of arch and dentition of maxillary posterior teeth before and after treatment and postretentios in patients treated with Quad-helix. Measurements and analysis were performed on study model with carlipers. Seventeen cases, eight boys and nine girls, were selected with average ages of 12.7 years. Mean retention period was 4 months, and mean wearing time was. 127 days. The result were as follows 1. The interpremolar widths and intermolar width were significantly increased in maxillary first piennolar and molar when compared between before and after treatment and postretention. The maxillary second premolar resulted in significant increase in interpremolar between after tretment and post retention. 2. The long axis of maxillary first premolar and first molar accompaning buccal tipping was significant increased before and after Tx and post retention. Significant increase of the lingual inclination of maxillary second premolar was obsered both in before and after Tx, and before Tx and post retention. 3. The distance between the height of tooth contour was significantly increased in the first and second premolar before and after Tx, and was significant increased in the first molar before and after Tx and post retention. 4. Intermolar width at the palatal groove was increased in before and after Tx. and post retention. The palatal depth was significant increased in before and after Tx. In conclusion expansion of maxillary dental arch showed no relapse and results were stable retention

• The Korean Journal of Emergency Medical Services
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• v.5 no.1
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• pp.63-71
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• 2001

Retention of CPR knowledge was assessed in a group of 86 police officers who participated in first aid and emergency rescue program on February, 2001 and 3 months later. Police officers were taken written test about CPR knowledge by American Heart Association Guidelines 2000 and competence level. Data were analyzed by Frequency, Percentage, Mean, paired t-test using SPSS program. The results for this study were as follows ; 1. In the post-test, the highest question was a rechecking time of circulation sign(98.8%), the lowest was a check for signs of circulation(17.4%), in 3months later, the highest question was a chest compression(94.2%), the lowest was a check for signs of circulation(1.2%), and a retention of CPR knowledge was a 71.7%. In 3months later, knowledge level was decreased compared to that of post-test(t=-9.09, p=.000). 2. In 3months later, the competence level was decreased compared to that of post-test(t=3.09, p=.003).

• Environmental Engineering Research
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• v.25 no.3
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• pp.400-408
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• 2020

Hydrodynamic study of Activated Sludge Process (ASP) is important to optimize the reactor performance and detect anomalies in the system. Residence time distribution (RTD) study has been performed using LiCl as tracer on a pilot scale aeration tank (AT) and ASP, treating the pulp and paper mill effluent. The hydraulic performance and treatment efficiency of the AT and ASP at different operating parameters like residence time, recycle rate was investigated. Flow anomalies were identified and based on the experimental data empirical models was suggested to interpret the hydrodynamics of the reactors using compartment modelling technique. The analysis of the RTD curves and the compartment models indicated increase in back-mixing ratio as the mean hydraulic retention time (MHRT) of the tank was increased. Bypassing stream was observed at lower MHRT. The fraction of dead zone in the tank increased by approximate 20-25% with increase in recycle rate. The fraction of the stagnant zone was found well below 5% for all performed experiments, which was under experimental error. The substrate removal of 91% for Chemical oxygen demand and 96% for Biochemical oxygen demand were observed for the ASP working at a hydraulic mean residence time 39 h MRT with a 20% recycling of activated sludge.

• The korean journal of orthodontics
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• v.41 no.3
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• pp.200-210
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• 2011

Objective: This study aimed at evaluating the changes in mandibular arch widths and buccolingual inclinations of mandibular posterior teeth after rapid maxillary expansion (RME). Methods: Baseline and post-expansion cone-beam computed tomographic (CBCT) images of patients who initially had bilateral posterior cross-bite and underwent RME with a banded-type expander were assessed in this study. The patients included 9 boys (mean age: $13.97{\pm}1.17$ years) and 11 girls (mean age: $13.53{\pm}2.12$ years). Images obtained 6 months after retention were available for 10 of these patients. Eighteen angular and 43 linear measurements were performed for the maxilla and mandible. The measurements were performed on frontally clipped images at the following time points; before expansion (T1), after expansion (T2), and after retention (T3). Statistical significance was assessed with paired sample $t$-test at $p$ < 0.05. Results: T1-T2 comparisons showed statistically significant post-RME increases for all measurements; similarly, T2-T1 and T3-T1 comparisons showed statistically significant changes. The maxillary linear and angular measurements showed decreases after expansion, and mandibular linear and angular measurements increased after retention. Conclusion: All mandibular arch widths increased and mandibular posterior teeth were uprighted after RME procedure.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.153-158
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• 1999

Uptakes of N and P by Phragmites japonica Steudel. are determined in continuous flow tanks as a function of hydraulic retention time (HRT, days) and nutrient concentration (NC). Results show that the uptake was higher at shorter HRT and higher nutrient concentration, and the regression equations were estimated. Mean above ground biomass of Phragmites japonica in the middle reaches of Sagimak stream was 335.92 g/$m^2$, and estimated uptake by this vegetation were 7.31~20.15 NH$_4$-N, 31.15~95.84 NO$_3$-N, and 4.09~11.48 PO$_4$-P mg/$m^2$/day in Sagimak stream, respectively when HRT was 1~5 days. According to this study, it is concluded that Phragmites japonica Steudel. are suitable for water quality improvement of stream through nutrient uptake at short HRT and high concentration.