• Journal of Korean Society of Environmental Engineers
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• v.34 no.4
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• pp.223-231
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• 2012

The purpose of this study is to investigate basically the mechanism of heat transfer by the resolution of complex fluid flow inside a sophisticated designed screw dryer for the treatment of sewage sludge by using numerical analysis and experimental study. By doing this, the result was quite helpful to obtain the design criteria for enhancing drying efficiency, thereby achieving the optimal design of a multiple screw type dryer for treating inorganic and organic sludge wastes. One notable design feature of the dryer was to bypass a certain of fraction of the hot combustion gases into the bottom of the screw cylinder, by the fluid flow induction, across the delicately designed holes on the screw surface to agitate internally the sticky sludges. This offers many benefits not only in the enhancement of thermal efficiency even for the high viscosity material but also greater flexibility in the application of system design and operation. However, one careful precaution was made in operation in that when distributing the hot flue gas over the lump of sludge for internal agitation not to make any pore blocking and to avoid too much pressure drop caused by inertial resistance across the lump of sludge. The optimal retention time for rotating the screw at 1 rpm in order to treat 200 kg/hr of sewage sludge was determined empirically about 100 minutes. The corresponding optimal heat source was found to be 150,000 kcal/hr. A series of numerical calculation is performed to resolve flow characteristics in order to assist in the system design as function of important system and operational variables. The numerical calculation is successfully evaluated against experimental temperature profile and flow field characteristics. In general, the calculation results are physically reasonable and consistent in parametric study. In further studies, more quantitative data analyses such as pressure drop across the type and loading of drying sludge will be made for the system evaluation in experiment and calculation.

• Korean Journal of Psychosomatic Medicine
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• v.18 no.2
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• pp.62-71
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• 2010

Objectives : The aim of the study was to investigate the prevalence by gender and to evaluate associations of depression, anxiety and sleep disturbances in a large sample of adolescents from the general population. Methods : 1422 subjects, aged 14 years students were recruited in the seven middle-school of the local community. The self-report questionnaire(Children's Depression Inventory : CDI, Beck Anxiety Inventory : BAI and Pittsburgh Sleep Quality Index : PSQI) was used for screening depression, anxiety and sleep disturbances in adolescent. CDI, BAI, and PSQI score was categorized into the following quartiles : $\leq$21, 22-25, 26-28, and $\geq$29 ; $\leq$21, 22-26, 27-31, and $\geq$32 ; $\geq$5, <5. The cut-off score is that CDI is 22, BAI is 22 and PSQI is 5. The result was analyzed using the independent t-test, the chi-square test and logistic regression analyses. Results : The mean CDI score($12.52{\pm}8.32$ vs. $10.39{\pm}7.52$ ; p=0.003), BAI($7.77{\pm}7.93$ vs. $9.84{\pm}9.04$ ; p<0.001) and PSQI($4.57{\pm}2.67$ vs. $3.64{\pm}2.30$ ; p=0.013) of girls were significantly higher than for boys. But, boys in the fourth quartile of CDI(CDI$\geq$29) and BAI(BAI$\geq$32) were at significantly elevated risk for sleep disturbances more than for girls after adjustment for sex, history of psychiatric treatment(CDI odd ratio, 14.66 ; 95% CI, 4.17-51.53, BAI odd ratio, 32.99 ; 95% CI, 4.26-255.39). Conclusion : The results suggest that high CDI, BAI score appears to increase the risk for developing sleep disturbances in boys more than girls.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.123-134
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• 2002

An experiment was conducted to establish the most suitable ventilation system for the enclosed nursery pig house in Korea, comparing four different ventilation systems ; i) air enters through perforated ceiling and exhausts through chimney (NA), ii) air enters through perforated ceiling and exhausts through side walls (NB), iii) air enters through perforated ducts and exhausts through side walls (NC) and iv) air enters through perforated ducts and exhausts through chimney(ND). The experiment was carried out during winter and summer separately. The experimental pigs were weaned at fourteen days old in winter (December-February) and at twenty one days old in summer (June-August). The main results of the experiment are as follows : A preliminary experiment showed that in the NC system during summer, air can reach all the pig rooms in the house and the air flow rates of the upper, middle (1.2 m height of the room) and low (at the height of pig stature) parts of the room were measured at 7.0-8.08, over 0.5 and over 0.2 m/s, respectively, which flow rates were much higher(p$<$0.05) than those in other system. At the minimum ventilation efficiency during winter, air flow rates of upper, middle and low parts of the room equipped with the NC system were detected at over 1, less than 0.5 and around 0.07 m/s, respectively. It is concluded that the separated ventilation system air-entering through ducts is the most suitable for the ventilation system of the enclosed nursery pig house and the exhausting system through side walls is more efficient for ventilation than the system through roof. Furthermore, to sustain proper temperature and reduce energy waste as well as heat consumption, a future research should be carried out to develop the environmental control system in relation to developing a heat regulator.

• Korean Journal of Psychosomatic Medicine
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• v.21 no.1
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• pp.3-10
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• 2013

Objectives : Many patients diagnosed with cancer suffer from various psychiatric symptoms such as depression, anxiety and insomnia as well as cancer itself. Patients with cancer are more vulnerable to possible adverse events of psychotropic medications. Although antidepressants are widely used among cancer patients, there is little information about tolerability of antidepressants. This study was conducted to compare tolerability of antidepressants in cancer patients referred for psychiatric consultation. Methods : The participants were cancer patients who had been referred to psychiatrist for their psychiatric symptoms. We retrospectively analyzed the data of patients diagnosed with cancer from 9 general hospitals in Korea. The discontinuation rate for a 6 months period after treatment initiation for three antidepressants(Escitalopram, Mirtazapine, Paroxetine) were compared. Results : Antidepressants were prescribed for 96.3% of subjects and Escitalopram 150(47.2%), Mirtazapine 92(28.9%) and Paroxetine 76(23.9%) were prescribed frequently in order There were no significant differences in discontinuation rates among the three antidepressants during the 6 month period after initiation of pharmacotherapy. But there was a difference in discontinuation rates between inpatients versus outpatients(p<0.0001). Conclusions : In a naturalistic setting for the antidepressant treatment for cancer patients, it seems that there are no differences in discontinuation rates among these three antidepressants. It is therefore essential that such interactions are carefully considered when treating patients of antidepressants who already have cancer.

• Clinical and Experimental Pediatrics
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• v.46 no.3
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• pp.277-283
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• 2003

Purpose : Craniopharyngiomas are often accompanied by severe endocrine disorders. Although there is universal growth hormone deficiency(GHD), the resulting growth pattern is very heterogeneous. We report the growth and endocrine outcome of 44 children with craniopharyngioma, with emphasis on initial symptoms, growth before and during growth hormone(GH) treatment and spontaneous growth in spite of GHD. Methods : We performed a retrospective study of 44 children treated at our centre between 1984 and 2002. Results : About 30% of patients had symptoms suggesting endocrine disorder at diagnosis. After surgery, multiple endocrinopathies were almost universal. Before GH therapy, height velocity was $8.00{\pm}2.71cm/yr$ in the normal growth group(n=11) and $1.79{\pm}1.10cm/yr$ in the subnormal growth group(n=7) during the first year and during the second year, $6.76{\pm}2.49cm/yr$ and $2.29{\pm}1.33cm/yr$, respectively. There was no difference of body mass index(BMI) change between before and after surgery in the two groups. Height standard deviation score(SDS) was $-1.46{\pm}0.74$ in the normal growth group and $-0.43{\pm}0.97$ in the subnormal growth group. Before GH treatment height SDS was $-1.31{\pm}1.25$ and BMI was $20.46{\pm}3.60$. During GH treatment, height SDS increased to $-0.60{\pm}1.37$ in the first, and to $-0.41{\pm}1.54$ in the second year(P<0.05), but BMI did not change significantly. Conclusion : The endocrine morbidity could develop in most children with craniopharyngioma before and after the operation and should be managed properly. Although all treated patients benefit from GH therapy, further studies are necessary to find out the possible mechanism of growth regulation in normally growing children, despite GH deficient.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.220-226
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• 2009

Purpose : Macrovascular complications are the main cause of mortality in type 1 diabetes mellitus (T1DM). The purpose of this study was to clarify the presence of early vascular changes and to assess the risk factors of macrovascular complications in young adults with T1DM diagnosed in childhood and adolescence. Methods : Seventy-two patients ($23.9{\pm}2.4$ years) with T1DM diagnosed before 18 years of age and twenty normal controls were included. The incidence of hypertension, dyslipidemia, and other risk factors of macrovascular complication were reviewed. Flow-mediated vasodilation (FMD) and mean intima-media thickness (IMT) measured by ultrasound were compared between patients and control subjects, and their correlations with macrovascular risk factors were analyzed. Results : Of the 72 patients, 32 (44.4%) had hypertension. The proportions of maleness (P=0.03) and mean body mass index (P=0.04) were higher in the hypertensive patients than in normotensive patients. Thirty-one (N=69, 44.9%) patients had dyslipidemia and LDL-cholesterol was positively correlated with mean HbA1c (r=0.32, P=0.008) and total daily insulin dose (r=0.27, P=0.02). The mean IMT was significantly higher in patients than in control subjects ($0.43{\pm}0.06$ mm vs $0.39{\pm}0.06$ mm, P=0.03). There was no difference in the value of FMD between patients and controls, but the duration of the disease after pubertal onset was negatively correlated with FMD (r=-0.34, P=0.01). Conclusion : Hypertension, dyslipidemia and atherosclerotic vascular change were observed in young adults with T1DM diagnosed during childhood and adolescence; this strongly suggests that meticulous screening of macrovascular complications and control of their risk factors should be conducted.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.227-233
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• 2009

Purpose : Growth hormone (GH) replacement after retesting is necessary because impairment of body composition and cardiovascular health has been more severe in adult patients with persistent GH deficiency (GHD) from childhood to adulthood. This study aimed to investigate the factors for persistent GHD and define a highly probable group of persistent GHD in young adults with childhood-onset GHD. Methods : GHD was reassessed by insulin tolerance test (ITT) in 55 adult patients (39 males, 16 females) with childhood-onset GHD. Twelve patients presented with idiopathic GHD and 43 patients presented with organic GHD caused by tumors involving the hypothalamus-pituitary (H-P) region (n=33), other brain tumors (n=3), meningitis (n=3), leukemia (n=2) and others (n=2). Results : Forty-nine (89.1%) of 55 patients had persistent GHD. IGF-I was positively correlated with log of peak GH (r=0.57, P<0.001). There was no difference in the proportion of persistent GHD between idiopathic and organic GHD. The percentage of patients with persistent GHD was 40%, 80%, and 95.6% for patients with zero, one, two or more additional pituitary hormone deficiencies (PHDs), respectively (P=0.002). The probability of persistent GHD was higher in patients with diseases involving the H-P region (P=0.003). GHD persisted in 15 of 18 patients treated with cranial irradiation. Conclusion : We suggest that the probability of persistent GHD in adulthood was high in patients with 2 or more additional PHDs, and diseases involving the H-P region.

• Journal of Gastric Cancer
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• v.9 no.3
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• pp.110-116
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• 2009

Purpose: The aim of this study was to examine the usefulness of positron emission tomography (PET)-computed tomography (CT) in the pre-operative staging of gastric cancer. Materials and Methods: Between February 2006 and August 2008, PET-CT and CT were performed on 70 patients diagnosed with gastric cancer by gastrofiberscopic biopsy. The sensitivities, specificities, Positive predictive value (PPV), and negative predictive value (NPV) of PET-CT and CT imaging for the detection of gastric cancer TNM staging were compared. Results: The detection rates for the primary tumor were as follows: PET-CT, 81.4% (57/70); and CT, 42.9% (30/70). For both early gastric cancer (EGC) and advanced gastric cancer (AGC), PET-CT was more accurate than CT in detecting the lesions. As the size of the tumor exceeded 3 cm, the detection rate increased. The sensitivities, specificities, PPV, and NPV of PET-CT for lymph node staging were 55.6%, 81%, 86.2%, and 45.9%, while the sensitivities, specificities, PPV, and NPV of CT were 40.0%, 85.7%, 85.7% and 40%, respectively. One case of multiple liver metastasis and two cases of dual primary cancer (rectal and pancreatic cancers) were detected by PET-CT. PET-CT also had a higher detection rate for all histologic types of primary tumors. PET-CT was more accurate than CT in detecting primary gastric cancer lesions. The detection of nodal metastasis by PET-CT was similar to CT; small-sized tumors or EGC detection rates were not high. However, PET-CT provided additional information to detect distant metastases and dual primary cancers and reduced unnecessary laparotomies to detect peritoneal seeding or carcinomatosis. Conclusion: It would be useful to make a pre-operative diagnosis of gastric cancer and determine treatment if PET-CT were added to other routine pre-operative studies.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1002-1007
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• 2012

The considerable portion of energy demand has been satisfied by the combustion of fossil fuel and the consequent $CO_2$ emission was considered as a main cause of global warming. As a technology option for $CO_2$ emission mitigation, absorption process has been used in $CO_2$ capture from large scale emission sources. To set up optimal operating parameters in $CO_2$ absorption and solvent regeneration units are important for the better performance of the whole $CO_2$ absorption plant. Optimal operating parameters are usually selected through a lot of actual operation data. However theoretical approach are also useful because the arbitrary change of process parameters often limited for the stability of process operation. In this paper, a theoretical approach based on vapor-liquid equilibrium was proposed to estimate optimal operating conditions of $CO_2$ absorption process. Two $CO_2$ absorption processes using 12 wt% aqueous $NH_3$ solution and 20 wt% aqueous MEA solution were investigated in this theoretical estimation of optimal operating conditions. The results showed that $CO_2$ loading of rich absorbent should be kept below 0.4 in case of 12 wt% aqueous $NH_3$ solution for $CO_2$ absorption but there was no limitation of $CO_2$ loading in case of 20 wt% aqueous MEA solution for $CO_2$ absorption. The optimal regeneration temperature was determined by theoretical approach based on $CO_2$ loadings of rich and lean absorbent, which determined to satisfy the amount of absorbed $CO_2$. The amount of heating medium at optimal regeneration temperature is also determined to meet the difference of $CO_2$ loading between rich and lean absorbent. It could be confirmed that the theoretical approach, which accurately estimate the optimal regeneration conditions of lab scale $CO_2$ absorption using 12 wt% aqueous $NH_3$ solution could estimate those of 20 wt% aqueous MEA solution and could be used for the design and operation of $CO_2$ absorption process using chemical absorbent.

• Journal of Aquaculture
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• v.8 no.3
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• pp.171-181
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• 1995

Gonadosomatic index (GSI) of the crucian carp (Carassius auratus) was investigated to clarify annual reproductive cycle from February in 1992 to October in 1994. The values of GSI were high with individual variation from April to July which period was coincided with the breeding season of fish. The GSI was very low in August and September, when follicular atresia developed in the ovaries. GSI value began to increase in October and reached a peak around the following March, which indicated that ovarian follicles may grow during this period. Human chorionic gonadotropin (HCG 10 IU), $17\alpha$, 20\beta-dihydroxyprogesterone\;(1-100{\mu}g/ml)$ and phorbol 12-myristate-13-acetate (TPA, protein kinase C activator, 0.1-10${\mu}M$) induced germinal vesicle breakdown (GVBD), but $4\alpha-phorbol$ 12, 13- didicanoate ($4\alpha-PDD,\;phorbol\; ester\;analogue,\;25{\mu}M$) did not induce germinal vesicle breakdown in the follicular oocytes. Prostaglandin $F_{2\alpha}$ $(0.1-10 {\mu}g/ml)$ and TPA $(0.1-10 {\mu}M$ induced ovulation of the oocytes, but $4\alpha-PDD$ $(25{\mu}M)$ did not induce ovulation of the follicles. $17\alpha-hydroxyprogesterone$ production was examined from the isolated follicles to investigate the steroid production ability in the crucian carp ovaries. HCG (1 lU, 10 lU) and forskolin (adenylate cyclase activator, 0.1-10 ${\mu}M$) stimulated $17\alpha-hydroxyprogesterone$ production. The time course of HCG (10 lU) and forskolin $(10\;{\mu}M)$ stimulated $17\alpha-hydroxyprogesterone$ production within 3 hours, the elevated levels were maintained during the rest of the culture period. The data indicates that cyclic AMP and protein kinase C may play important roles in the oocyte maturation and ovulation in crucian carp.