• Journal of Korean society of Dental Hygiene
• /
• v.15 no.1
• /
• pp.91-99
• /
• 2015

Objectives: The purpose of the study was to investigate the relationship between internet addiction and health in dental hygiene students. Methods: A self-reported questionnaire was completed by 216 dental hygiene students in Daegu from June 9 to 13, 2014. Data were analyzed by descriptive statistics, t-test, and ANOVA using SAS 9.2 program. The instruments included Korean internet addiction scale(K scale) and Korean version of the general health questionnaire. General characteristics consisted of grade, religion, residential types, economic condition, place of internet use, duration, purpose, and time of use. Physical characteristics consisted of subjective physical condition, smoking, alcohol drinking, exercise above twice per week, musculoskeletal disease, and location of physical symptoms. Psychiatric scale and 6 questions of physical characteristics were consulted by the statistician of preventive medicine department. Results: Internet users over 4 hours manifested the poor mental health, while those who uses internet under 2 hours showed good mental health(F = 1.41, p < 0.01). The students having good physical condition showed better mental health than those with poor physical condition(t = -2.81, p < 0.01). The students exercising at least twice a week showed better mental health than those who do not exercise(t = -3.10, p < 0.01). Those who having musculoskeletal symptoms showed higher index of internet addiction score than those who do not(t = 4.21, p < 0.01). Those who have no musculoskeletal symptoms tended to have better mental health than those who have musculoskeletal symptoms(t = 2.28, p < 0.05). The variables correlated to mental health were internet addiction, subjective physical condition, and exercise at least twice a week. The severity level of internet addiction leads to poor mental health(r = 0.26, p < 0.001). Conclusions: Internet addiction is closely related to mental health. So the students must know the danger of internet addiction. Proper health education is necessary for the prevention of addiction symptoms.

• 한국태양에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.259-264
• /
• 2009

Most of the fossil power plants firing lower grade coals are challenged with maintaining good combustion conditions while maximizing generation and minimizing emissions. In many cases significant derate, availability losses and increase in unburned carbon levels can be attributed to poor combustion conditions as a result of poorly controlled local fuel and air distribution within the boiler furnace. The poor combustion conditions are directly related to the gas flow deviation in upper furnace and convection tube-bank but a less reported issue related to in large-scale oppose wall fired boilers. In order to develop a on-line combustion monitoring system and suggest an alternative heat flux estimation method at tube bank, which is very useful information for boiler design tool and blower optimizing system, field test was conducted at operating power boiler. During the field test the exhaust gases' temperature and tube metal temperature were monitored by using a spatially distributed sensors grid which located in the boiler's high temperature vestibule region. At these locations. the flue gas flow is still significantly stratified, and air in-leakage is minimal which enables tracing of poor combustion zones to specific burners and over-fire air ports. Test results showed that the flue gas monitoring method is more proper than metal temperature distribution monitoring for real time combustion monitoring because tube metal temp. distribution monitoring method is related to so many variables such as flue gas, internal flow unbalance, spray etc., Heat flux estimation at the tube bank with flue gas temp. and metal temp. data can be alternative method when tube drilling type sensor can't able to use.

• Journal of Chest Surgery
• /
• v.46 no.6
• /
• pp.449-456
• /
• 2013

Background: Tumor recurrence is the most common cause of treatment failure, even after complete resection of early-stage non-small cell lung cancer (NSCLC). In this study, we investigated the prognosis of patients with early recurrence in order to identify independent risk factors related to early recurrence. Methods: Between February 1995 and December 2012, 242 patients who underwent surgical resection for stage I NSCLC at Dong-A University Hospital were reviewed. The factors predicting overall survival (OS) and early recurrence were investigated. We also investigated the relationship between the patterns and period of recurrence and clinicopathological factors. Results: For patients with stage IA and IB NSCLC, the 5-year OS rate was 75.7% and 57.3% (p=0.006), respectively. A multivariate Cox proportional hazards model demonstrated that gender (p=0.004), comorbidity number (p=0.038), resection type (p=0.002), and tumor size (p=0.022) were the statistically significant predictors of OS. Moreover, the multivariate analysis revealed that smoking history (p=0.023) and histologic grade (p=0.012) were the independent predictors of early recurrence. Additionally, only histologic grade (poor differentiation) was found to be significantly associated with a higher frequency of distant metastasis; there was no relationship between the patterns and period of recurrence and clinicopathological factors. Conclusion: The present study demonstrated that smoking history and histologic grade were independent prognostic factors for early recurrence within two years in patients with early-stage NSCLC. Patients with these predictive factors may be good candidates for adjuvant therapy.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.4
• /
• pp.409-418
• /
• 2017

This work attempted to manufacture glued-laminated timber (Glulam) bonded with melamine-urea-formaldehyde (MUF) resin adhesives at various melamine contents from 20% to 50% under high frequency (HF) heating for a very short time. Two preparation methods were employed to prepare MUF resin adhesives with different melamine contents: one-batch method of synthesizing MUF resins in a single batch, and two-batch method of mixing urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized separately. As the melamine content increased, the gelation time and peak temperature of MUF resins decreased. The adhesion performance of plywood showed that the one-batch MUF resin adhesive with 50% melamine content only satisfied the standard requirement of water resistance. Thus, the one-batch MUF resin adhesive with 50% melamine content was applied for bonding wood lamina from four softwood species such as Japanese larch, Korean red pine, Korean pine and Japanese cedar to manufacture Glulam under HF heating. All Glulam samples bonded with the one-batch MUF resin adhesives with 50% melamine content except those from Korean Red Pine satisfied the requirement in water soaking or boiling water delamination test as an exterior grade Glulam. The presence of rosin in Korean Red Pine was believed to be responsible for its poor adhesion. These results showed that the one-batch MUF resin adhesives with 50% melamine content provided acceptable water resistance with exterior grade Glulam manufactured under HF heating.

• Journal of The Korean Association For Science Education
• /
• v.20 no.1
• /
• pp.1-11
• /
• 2000

This study investigated both elementary and middle school students' abilities of reading scales and students' conceptions of measuring instruments and units. Seventy two students with 5th grade, sixty nine students with 7th grade, and eighty students with 9th grade were participated. Performance tests and written questionnaires were used. To assess their scale reading abilities, individual performance test was used. Every student should measure length of an envelope, temperature of water, volume of water, etc. And to find out students' conceptions related with measuring instruments and units, written questionnaires with pictures and photographs were used. Some of the students' abilities of reading scales were considerably poor. The results of a two-plate-balance and measuring-cylinder were worse than those of a ruler, a spring-balance, and a thermometer. Many of the students had misconceptions related with measuring instruments. Some of them did not know exactly the meaning of volume, or mass, or force. So they did not know what to measure with the measuring instruments. Also students were confused with several units of volume, force, weight and mass.

• Journal of Educational Research in Mathematics
• /
• v.18 no.3
• /
• pp.283-308
• /
• 2008

A poor achievement of basic competency leads to obstacles of the same subject and other subjects from a series of accumulative losses and social life. The Grade 3 National Diagnostic Assessment of Basic Competency (NDAHC) dated from 2002, Teaching Plan Responsible to Basic Competency and compensational education materials for students of the below-basic level has marked a line in the chain of policy to realize educational welfare. The goal of NDABC is to collect information of the reason with regard to learning deficiency and individual student's information, and ultimately teach them on the basis of those informations. This study analyzed the characteristics of below-basic students in the basic mathematics with data from NDABC from 2003 to 2007. Students of the below-basic level were affected in achievement by numerical distinction, regrouping, arrangement and descriptive form of item, information-providing way, typical example, familiarity, frequency in use in daily life etc. This study provides a basic important information with regard to teaching below-basic students and suggestions with compensational education materials for them.

• Journal of Korean Neurosurgical Society
• /
• v.29 no.7
• /
• pp.918-922
• /
• 2000

Objective : The authors analyzed the results of management outcomes for basilar bifurcation aneurysms treated with transcranial surgery and endovascular surgery. Methods : At the authors' institution between May 1989 and December 1998, 47 aneurysms with 45 patients were treated with transcranial surgery including surgical clipping/wrapping and endovascular surgery for basilar bifurcation aneurysms. The medical records and neuroimaging studies of the patients were reviewed retrospectively. Results : Of the 45 patients, 87 percent of the aneurysms were ruptured and 13% unruptured. Forty six percent of the patients had multiple aneurysms including basilar bifurcation aneurysm. Of the 39 patients with subarachnoid hemorrahge, 77% were in good neurological status(Hunt Hess grade I-III), 23% were in poor grade(H-H grade IV-V). Thirty two patients were treated with transcranial surgery and 15 patients were treated with endovascular surgery. Two patients who had treated with wrapping surgery later bled during follow-up period and treated with endovascular surgery. The management outcome of the transcranial surgery was : Glasgow outcome scale(GOS) I 66%, GOS II 12.5%, GOS III 6.3%, GOS IV 6.3% and GOS V(death) 9.4%. The major causes of morbidity related to transcranial surgery were perforator occlusion, vasospasm and retraction injury. The management outcome of the endovascular surgery was : GOS I 66.7%, GOS II 6.7%, and GOS V 26.7%. The major causes of mortality related to endovascular surgery were related to intraoperative aneurysmal bleeding. Conclusion : This report documents that more than 75% of patients undergoing treatment either transcranial or endovascular surgery can expect good clinical outcomes. Treatment modality in management of basilar bifurcation aneurysm must be carefully selected based on various considering factors.

• Journal of Korean Neurosurgical Society
• /
• v.40 no.3
• /
• pp.148-153
• /
• 2006

Objective : The authors conducted this study to present the long-term treatment outcomes [minimum 2 years] of Gamma knife radiosurgery[GKS] for trigeminal neuralgia[TN] and to demonstrate the correlation of treatment outcomes and the anatomical characteristics of TN. Methods : From 1997 to 2003, 44 consecutive patients suffering from medically intractable pain underwent GKS for TN. A single 4mm collimator was used with a median maximum dose of 80Gy [range $75{\sim}80Gy$] prescribed to the root entry zone of the trigeminal nerve. Median follow up duration was 30 months [range $24{\sim}78\;months$]. Anatomical measurements of trigeminal nerve in magnetic resonance images during GKS planning were correlated with clinical outcome. Results : Twenty-two patients [50%] achieved an excellent outcome [BNI grade I & II], 20 patients [45.5%] a good outcome [grade IIIa & IIIb], and only 2 patients [4.5%] a poor outcome [grade IV & V]. Eleven patients [25.0%] experienced pain recurrence after initial pain relief. Smaller volume of trigeminal nerve area irradiated more than 40Gy was significantly correlated with excellent outcome in both univariate and multivariate analyses respectively [P=0.033 and 0.040]. Conclusion : Anatomical considerations during the planning of GKS would be helpful for predicting clinical outcome in TN.

• Nutrition Research and Practice
• /
• v.6 no.4
• /
• pp.328-333
• /
• 2012

This study was performed to investigate the differences in food choice, nutrition labeling perceptions, and prevalence of obesity due to meal skipping in Korean elementary school children. A national survey was performed in 2010 to collect data on food intake frequency, understanding of nutrition labeling, and body mass index from 2,335 fifth grade students in 118 elementary schools selected from 16 metropolitan local governments by stratified cluster sampling. The data were analyzed using the SAS 9.1 and SUDAAN 10.0 packages. Students who consumed three meals for 6-7 days during the past week were classified into the regular meal eating (RM) group (n = 1,476) and those who did not were placed into the meal skipping (MS) group (n = 859). The daily intake frequency of fruits, vegetables, kimchi, and milk was significantly lower in the MS group compared to that in the RM group (P < 0.001), whereas the daily intake frequency of soft drinks and instant noodles (ramyeon) was significantly higher in the MS group than that in the RM group (P < 0.05). The MS group demonstrated a significantly lower degree of understanding with regard to nutrition labeling and high calorie foods containing low nutritional value than that in the RM group. The distribution of obesity based on the percentile criteria using the Korean growth chart was different between the MS and RM groups. The MS group (8.97%) had a higher percentage of obese subjects than that in the RM group (5.38%). In conclusion, meal skipping was related to poor food choice, low perception of nutrition labeling, and a high prevalence of obesity in Korean fifth grade children.

• Journal of Animal Science and Technology
• /
• v.53 no.6
• /
• pp.525-532
• /
• 2011

Insufficient pre-slaughter fasting leaves serious amount of feed-like contents (designated here as un-fasted stomach spent feed, USSF) in the eviscerated pig stomach. This study was intended to evoke economical and environmental seriousness of USSF discharge by estimating its value as pig feed. For finishing pigs feeding trial, three levels (0, 5, and 10%) of USSF were blended with pig feed to prepare control and two treatment diets, respectively. A total of 42 (21 males, 21 females) crossbred (Landrace ${\times}$ Yorkshire ${\times}$ Duroc) finishing pigs weighing $81.5{\pm}8.0$ kg were employed to 28d feeding trial and in vivo digestibility trial by $Cr_2O_3$ indicator method with 7 males and 7 female pigs per treatment. In vitro total tract digestion of USSF showed 70.5% and 57.6% of DM and OM digestibilities, respectively which were poorer (p<0.05) than those of pig diet. There were no differences in body weight gain, daily feed intake and feed conversion ratio among treatments although 10% USSF substitution exerted relatively poor performance. In vivo apparent digestibilities of diets containing USSF 5% and 10% were lower (p<0.05) than that of 100% pig feed. There were no differences (p>0.05) in dressing percentage and carcass grade among treatments. Results of this study showed that 5% USSF substitution in finishing pigs diet did not exert any disadvantage in terms of production performance and carcass grade. This study implied that un-fasted slaughter causing excessive excretion of USSF should be avoided. If not avoidable, the USSF should not be wasted in abattoir but could be recycled as pig feed.