• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.320-329
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• 2023

Cadmium (Cd), a heavy metal found in the aquatic environment, accumulates in organisms through the food chain. In the study, we investigated the survival rates, measurement of body Cd levels, and expression analysis of the stress response genes (Heat shock protein 70: HSP70 and Heat shock protein 60: HSP60) and antioxidant enzyme Glutathione S-Transferases (GST) on benthic oligochaete worm Tubifex tubifex exposed three concentrations of Cd, to analyze the bioaccumulation and changes of stress gene expressions to exposure toxicity of the Cd-spiked sediment. Survival rates of T. tubifex exposed to the Cdspiked sediment were 93% at 0.4 mg kg^-1 Cd, 96% at 1.87 mg kg^-1 Cd, and 93% at 6.09 mg kg^-1 Cd for 10 days. Cd concentration in the body of T. tubifex was higher than that in the sediment. After Cd exposures for 10 days, the body Cd levels were 18.4 mg kg^-1, 13.06 mg kg^-1, and 79.11 mg kg^-1 at exposed three concentrations of Cd, respectively. Upregulation of HSP70 gene expression was observed at all concentrations of exposed Cd as a time-dependent manner, whereas transcriptional expression of the HSP60 gene increased as a timedependent manner in T. tubifex exposed to the relative high concentration (6.09 mg kg^-1) of Cd. However, GST gene expression increased on day 1 at all concentrations after Cd exposures, and then downregulated until 10 days. These results indicate to ecotoxicological and molecular effects in benthic oligochaete worm T. tubifex to Cd-spiked sediment and provide the basic information for the utilization of environmental toxicity assessment using the T. tubifex as a aquatic pollution indicator species.

• Journal of Korean Dental Hygiene Science
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• v.1 no.1
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• pp.23-36
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• 2018

This research has been conducted from June 1, 2017 to August 25, 2017 for the dental hygienists working in Busan and Gyeongnam area, to provide necessary basic data for the purpose of revision of the relating laws from the analysis of their understanding and perspective on such laws through 262 subjects' questionnaire. Its analysis of their perspectives are as follows. 1. The common characteristics of the subjects are that 40.1% of them are under 25, and their working period was under three years with the 38.9%, and as for their marital status, 70.2% were single, the final education of 80.2% were associated degrees. Their working areas are centered in Gyeongsangnam-do province with 91.2%, the workplace type is for the dental clinic with 80.2%. 2. The comparison of the view point of the medical(technician) law according to the characteristics of the research subjects differed only whether or not the completion of the education, and as a result of the comparison according to the characteristics of those subjects understanding the details of the medical(technician) law, there was a significant difference saying "the current law has clear job description" depending on the working area or "the job duty is definite" depending on the job experience and job details. As for those saying "the job duty is definite", there was also significant difference depending upon marital status, final education and work details. There was no significant difference in all characteristics from findings of the necessity of legal system according to the subjects not understanding the medical(technician) law. 3. As a result of comparing the necessity of the medical(technician) law according to the characteristics of the research subjects, it was found that all the subjects accepted the necessity of the medical law revision including the dental hygienist in the medical person. The "necessity of the professional dental hygienist system" showed a significant difference depending upon the final education and medical institution type. Among the triggering factors in its amendment, there showed significant difference in the "cooperation of other organizations" and "solution of medical law problems" only in the final education. 4. As a result of comparison of the needs of the medical(technician) law revision according to the characteristics of the research subjects, it was found that the significant traits related to the age and job details showed "Legal responsibility would be increased" when the medical law is revised, in case that "it will help broaden the job extension", there showed a significant difference in career, final education, and working institution, and job details. "Legal protection is possible" showed significant difference except the age group and working area, and "it help the system settlement" showed in the final education. There was a significant difference in career, final education, and job details that "I can regulate the education and field practice", and the same in "my status will be improved" depending upon the final education, work area, and job details. Accordingly, in this research, for the establishment of more professional and comprehensive dental health service as suggested from the demand and necessity toward the medical(technician) Law by the dental hygienists.

• Journal of the Korean Society of Radiology
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• v.82 no.1
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• pp.128-138
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• 2021

Purpose We evaluated the risk factors for progression to chronic complicated bronchopleural fistula (BPF) after pulmonary resection using follow-up CT. Materials and Methods We retrospectively reviewed 45 cases with BPF that had undergone pulmonary resection during 2010-2018. We compared the clinical and radiological characteristics of those with complicated BPF (n = 24) and those without complicated (sterilized) BPF (n = 21). The clinical and radiological risk factors for progression to chronic complicated BPF were examined by logistic regression analysis. Results The thickness of the pleural cavity wall (p = 0.022), the size of the pleural cavity (p = 0.029), and the size increase of BPF on follow-up (p = 0.012) were significantly different between the two groups. The risk factors for progression to chronic complicated BPF were age > 70 years (odds ratio, 6.43; 95% confidence interval, 1.2-33.7), the thickness of the cavity wall > 5 mm (odds ratio, 52.5; 95% confidence interval, 5.1-545.4), and an increase in the size of the pleural cavity on follow-up CT (odds ratio, 12.5; 95% confidence interval, 2.1-73.5), only in the univariate analysis. Conclusion The risk factors for progression to chronic complicated BPF can be evaluated using follow-up CT.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.34 no.4
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• pp.109-116
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• 2024

β-Ga₂O₃ is a representative ultra-wide bandgap (UWBG) semiconductor that has attracted much attention for power device applications due to its wide-bandgap of 4.9 eV and high-breakdown voltage of 8 MV/cm. In addition, because solution growth is possible, it has advantages such as fast growth rate and lower production cost compared to SiC and GaN [1-2]. In this study, we have successfully grown Si-doped 10 mm thick Si-doped β-Ga₂O₃ single crystals by the EFG (Edge-defined Film-fed Growth) method. The growth direction and growth principal plane were set to [010] / (010), respectively, and the growth speed was 7~20 mm/h. The as-grown β-Ga₂O₃ single crystal was cut into various crystal planes (001, 100, ${\bar{2}}01$) and off-angles (1^o, 3^o, 4^o), and then surface processed. After processed, the homoepitaxial layer was grown on the epi-ready substrate using the HVPE (Halide vapor phase epitaxy) method. The processed samples and the epi-layer grown samples were analyzed by XRD, AFM, OM, and Etching to compare the surface properties according to the crystal plane and off-angle.

• Childhood Kidney Diseases
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• v.4 no.1
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• pp.77-83
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• 2000

Purpose: Pregnancy in transplanted mother is considered as a high-risk pregnancy, and significant incidences of prematurity and low-birthweight(LBW) infants have been reported. The objective of this study is to examine the outcome of pregnancy in transplanted mothers and to evaluate the current growth status in their children. Patients and Methods: We retrospectively reviewed 54 pregnancies in 40 kidney recipients until June 1999. Outcomes of pregnancy were reviewed and assessment of the current growth status in children was performed. Results: 54 pregnancies in 40 recipients were identified; 22 ended in termination of pregnancy because of unwanted pregnancy or therapeutic purposes. And of the other 32, 29 livebirths resulted in 28 recipients. The mean age of conception was $30.3{\pm}3.8$ years, with a mean interval from transplantation to conception of $35.9{\pm}23.2$ months. All patients were maintained on immunosuppressive regimens. Incidence of drug-treated hypertension(HTN) prior to pregancy was $52\%$, HTN during pregnancy, $48\%$; preeclampsia, $41\%$; urinary tract infection, $48\%$; oligohydramnios $4\%$; and no rejection during pregnancy and up to 3month post delivery. Of the 29 liveborn infants, prematurity(<37wk) occurred in $52\%$, LBW(<2500g) in $62\%$, VLBW(<1500g) in $7\%$ and $48\%$ born intrauterine growth retardation(IUGR). Mean gestational age was $36.3{\pm}3.0\;wk$; a mean birthweight, $2.23{\pm}0.6\;kg$; a mean birth-height, $45.1{\pm}3.6cm$. Current mean height standard deviation score (height SDS) was $0.29{\pm}0.91$ and mean weight SDS was $0.62{\pm}1.34$. Only one child($4\%$) under 1 year of age was below 10 percentile in height. Most of children had no medical problems except for 4 children; cleft palate(1), tuberous sclerosis(1), essential hematuria(1), and one child expired due to sepsis. Conclusion: This study showed similar incidence of premaure birth($57\%$) and low birth weight infants($62\%$), but lower incidence of spontaneous abortion($5.6\%$) was observed and compared to other studies. Postnatal growth in majority of children($96\%$) achieved catch-up growth before 1 year. Present study supports a more optimistic view of pregnancy in renal transplant mother and normal growth in their children.

• Pediatric Infection and Vaccine
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• v.12 no.2
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• pp.166-177
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• 2005

Purpose : The purpose of this study was to examine the molecular epidemiology and genetic variability of adenovirus(Ad) serotypes Ad1, Ad2, and Ad5 over 14 years in Korea. Methods : A total of 382 adenoviral strains isolated from the nasopharyngeal aspirates of children with lower respiratory tract infections in Seoul, Korea from November 1990 to February 2003 were serotyped by neutralization assay with type-specific antisera. Viral DNAs were extracted from infected cell lysates by the modified Hirt procedure. Genome type(GT) was determined by DNA restriction analysis with 12 restriction enzymess(BamHI, BclI, BglI, BglII, BstEII, EcoRI, HindIII, HpaI, SalI, SmaI, XbaI, and XhoI). To evaluate the genetic relatedness, pairwise comigrating restriction fragments(PCRF) analysis was performed. Results : Of 382 strains, 33 strains(9%) were Ad1, 45 strains(12%) were Ad2, and 24 strains(6%) were Ad5. Eighteen GTs(Ad1p1-Ad1p7, Ad1a, Ad1b, Ad1b1-Ad1b3, Ad1c, Ad1d, Ad1e, Ad1e1, Ad1e2, Ad1f) among Ad1, 24(Ad2p1-Ad2p11, Ad2a, Ad2a1-Ad2a6, Ad2b, Ad2c, Ad2d, Ad2e, Ad2e1-Ad2e3) among Ad2, and 10(Ad5p1, Ad5p2, Ad5a, Ad5a1-Ad5a7) among Ad5 strains were identified. One or two strains of the vast majority of GTs were isolated during the study period while a few GTs were identified sporadically with more than 2 strains. It is notable that some GTs such as Ad1p5 and Ad5a1 appeared in cluster during a short period. In analysis of genetic relatedness, the degree of PCRFs(pairwise comigrating restriction fragments) for Ad1 varied from 79 to 99%, for Ad2, 82 to 99%, and for Ad5, 85 to 99%. Conclusion : This study established the comprehensive nomenclature systems of Ad1, Ad2, and Ad5. Diverse GTs identified in this study have crucial implications in the genomic diversity and epidemiological characteristics of Ad1, Ad2, and Ad5.

• Clinical and Experimental Pediatrics
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• v.52 no.10
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• pp.1090-1102
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• 2009

Purpose:To evaluate current feeding practices and maternal nutritional knowledge on complementary feeding. Methods:Mothers of babies aged 9-15 months who visited pediatric clinics of 14 general hospitals between September and December 2008 were asked to fill questionnaires. Data from 1,078 questionnaires were analyzed. Results:Complementary food was introduced at 4-7 months in 89% of babies. Home-made rice gruel was the first complementary food in 93% cases. Spoons were used for initial feeding in 97% cases. At 6-7 months, <50% of babies were fed meat (beef, 43%). Less than 12-month-old babies were fed salty foods such as salted laver (35%) or bean-paste soup (51%) and cow's milk (11%). The following were the maternal sources of information on complementary feeding: books/magazines (58%), friends (30%), internet web sites (29%), relatives (14%), and hospitals (4%). Compared to the 1993 survey, the incidence of complementary food introduction before 4 months (0.4% vs. 21%) and initial use of commercial food (7% vs. 39%) had decreased. Moreover, spoons were increasingly used for initial feeding (97% vs. 57%). The average maternal nutritional knowledge score was 7.5/10. Less percentage of mothers agreed with the following suggestions: bottle formula weaning before 15-18 months (68%), no commercial baby drinks as complementary food (67%), considering formula (or cow's milk) better than soy milk (65%), and feeding minced meat from 6-7 months (57%). Conclusion:Complementary feeding practices have considerably improved since the last decade. Pediatricians should advise timely introduction of appropriate complementary foods and monitor diverse information sources on complementary feeding.

• Journal of Chest Surgery
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• v.38 no.7 s.252
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• pp.483-488
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• 2005

Aortic valve-sparing procedures could reduce valve-related morbidity, but may increase operative risks; therefore, these procedures could not be performed routinely. We attempted to find out the early results while focusing on the operative risks associated with these procedures in our hospital. Material and Method: From May 1996 to July 2003, 26 patients underwent these procedures including 15 patients with Marfan syndrome and 1 patient with Behcet disease. There were 17 men and 9 women with mean age of $37.9\pm19.2$ years (range: 6 months-74 years). Ten patients had ascending aortic dissection, 18 patients had more than moderate degree of aortic valve insufficiency (AI). Two types of valve-sparing procedures were performed: valve reimplantation in 14 and root remodeling in 12 patients. Associated procedures were performed as follows: aortic valve plasty in 6, mitral valve plasty in 5, hemi-arch replacement in 4, total arch replacement in 2, coronary artery bypass surgery in 1 and Maze procedure in 1 patient(s). Result: In four patients, valve-sparing procedures were converted to Bentall procedures during operation. Including these patients, there was no operative deaths, 3 patients underwent re-operation due to bleeding, 1 patient had permanent pacemaker. The median duration of ICU stay was 45.5 hours, the median duration of hospital stay was 10.5 days. In 22 patients excluding 4 converted patients, intraoperative transesophageal echocardiogram (TEE) showed less than mild degree of AI in all except one who had not received intra-operative TEE in the beginning and showed moderate degree of AI at discharge. The mean duration of follow-up was $21.2\pm27.4$ months. All patients were alive except one who died during other departmental surgery. In 3 patients, more than moderate degree of AI was recurred, but there were no reoperation. Conclusion: Aortic valve-sparing procedures could be performed relatively safely in selected patients who had annuloaortic ectasia.

• Journal of Korean Neurosurgical Society
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• v.30 no.10
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• pp.1210-1219
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• 2001

Introduction : The purpose of this study was to analyze the safety, pullout strength and radiographic characteristics of unicortical and bicortical screws of cervical facet within cadaveric specimens and evaluate the influence of level of training on the positioning of these screws. Methods : Twenty-one cadavers, mean 78.9 years of age, underwent bilateral placement of 3.5mm AO lateral mass screw from C3-C6(n=168) using a slight variation of the Magerl technique. Intraoperative imaging was not used. The right side(unicortical) utilized only 14mm screws(effective length of 11mm) while on the left side to determine the length of the screw after the ventral cortex had been drilled. Three spine surgeons(attending, fellow, chief resident) with varying levels of spine training performed the procedure on seven cadavers each. All spines were harvested and lateral radiographs were taken. Individual cervical vertebrae were carefully dissected and then axial radiographs were taken. The screws were evaluated clinically and radiographically for their safety. Screws were graded clinically for their safety with respect to the spinal cord, facet joint, nerve root and vertebral artery. The grades consisted of the following categories : "satisfactory", "at risk" and "direct injury". Each screw was also graded according to its zone placement. Screw position was quantified by measuring a sagittal angle from the lateral radiograph and an axial angle from the axial radiograph. Pull-out force was determined for all screws using a material testing machine. Results : Dissection revealed that fifteen screws on the left side actually had only unicortical and not bicortical purchase as intended. The majority of screws(92.8%) were satisfactory in terms of safety. There were no injuries to the spinal cord. On the right side(unicortical), 98.9% of the screws were "satisfactory" and on the left side(bicortical) 68.1% were "satisfactory". There was a 5.8% incidence of direct arterial injury and a 17.4% incidence of direct nerve root injury with the bicortical screws. There were no "direct injuries" with the unicortical screws for the nerve root or vertebral artery. The unicortical screws had a 21.4% incidence of direct injury of the facet joint, while the bicortical screws had a 21.7% incidence. The majority of "direct injury" of bicortical screws were placed by the surgeon with the least experience. The performance of the resident surgeon was significantly different from the attending or fellow(p<0.05) in terms of safety of the nerve root and vertebral artery. The attending's performance was significantly better than the resident or fellow(p<0.05) in terms of safety of the facet joint. There was no relationship between the safety of a screw and its zone placement. The axial deviation angle measured $23.5{\pm}6.6$ degrees and $19.8{\pm}7.9$ degrees for the unicortical and bicortical screws, respectively. The resident surgeon had a significantly lower angle than the attending or fellow(p<0.05). The sagittal angle measured $66.3{\pm}7.0$ degrees and $62.3{\pm}7.9$ degrees for the unicortical and bicortical screws, respectively. The attending had a significantly lower sagittal angle than the fellow or resident(p<0.05). Thirty-three screws that entered the facet joint were tested for pull-out strength but excluded from the data because they were not lateral mass screws per-se and had deviated substantially from the intended final trajectory. The mean pull-out force for all screws was $542.9{\pm}296.6N$. There was no statistically significant difference between the pull-out force for unicortical($519.9{\pm}286.9N$) and bicortical($565.2{\pm}306N$) screws. There was no significant difference in pull-out strengths with respect to zone placement. Conclusion : It is our belief that the risk associated with bicortical purchase mandates formal spine training if it is to be done safely and accurately. Unicortical screws are safer regardless of level of training. It is apparent that 14mm lateral mass screws placed in a supero-lateral trajectory in the adult cervical spine provide an equivalent strength with a much lower risk of injury than the longer bicortical screws placed in a similar orientation.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.1094-1104
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• 1997

Background : Spontaneous pneumothoraces(SP) are divided into primary spontaneous pneumothoraces (PSP) which develop in healthy individuals without underlying pulmonary disorders and secondary spontaneous pneumothoraces(SSP) which occur in those who have underlying disorders such as tuberculosis or chronic obstructive lung diseases. Yet there is no established standard therapeutic approach to this disorder, i.e., from the spectrum of noninvasive treatment such as clinical observation with or without oxygen therapy, to aggressively invasive thoracoscopic bullectomy or open thoracotomy. Although chest tube thoracostomy has been most widely used, the patients should overcome pain in the initiation of tube insertion or during indwelling it potential infection and subcutaneous emphysema. Thus smaller-caliber tube has been challenged for the treatment of pneumothorax. Previously, we studied the therapeutic efficacy of 8 French catheter for spontaneous pneumothorax. But there has been few data for effectiveness of small-caliber catheterization in comparison with that of chest tube. In this study, we intended to observe the long-term effectiveness of 8 French catheter for the treatment of spontaneous pneumothoraces in comparison with that of chest tube thoracostomy. Method : From January, 1990 to January, 1996, sixty two patients with spontaneous pneumothoraces treated at Chung-Ang University Hospital were reviewed retrospectively. The patients were sub-divided into a group treated with 8 French catheter(n=23) and the other one with chest tube insertion(n=39). The clinical data were reviewed(age, sex, underlying pulmonary disorders, past history of pneumothorax, size of pneumothorax, follow-up period). And therapeutic effect of two groups was compared by treatment duration(duration of indwelling catheter or tube), treatment-associated complications and recurrence rate. Results : The follow-up period(median) of 8 French catheter group and chest tube group was 28 and 22 months, which had no statistical significance. Ther was no statistically significant difference of clinical characteristics between two groups with SP, PSP, SSP. The indwelling time of 8 French catheter group was $6.2{\pm}3.8$ days, which was significantly shorter than that of chest tube group in SP, $9.1{\pm}7.5$ days(p=0.047). In comparison of treatment-related complication in PSP, 8 French catheter group as 6.25% of complication showed lower tendency than the other group as 23.8% (p=0.041 ; one-tailed, p=0.053; two-tailed). The recurrence rate in each group of SP was 17.4%, 10.3%, which did not show any statistically significant difference. Conclusion : Treatment with 8 French catheter resulted in shorter indwelling time in sponteous pneumothorax, and lower incidence of treatment-related complication in primary spontaneous pneumothorax. And the recurrence rate in each of treatment group showed no statistically significant difference. So, we can recommend the 8 French small-caliber catheter for the initial therapy for spontaneous pneumothorax for the replacement of conventional chest tube thoracostomy. But further prospective study with more subjects of spontaneous pneumothorax will be needed for the evaluation of effectiveness of 8 French cateter.