• Journal of Oral Medicine and Pain
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• v.31 no.3
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• pp.211-221
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• 2006

Purpose The aims of this study were to evaluate micro-tensile bond strength of composite resin bonded to dentin following high-speed rotary handpiece preparation or Er:YAG laser preparation with two different adhesive systems and to assess the influence of different Er:YAG laser energies on the micro-tensile bond strength. Materials and Methods In this study, 40 third morlars were used. Flat dentin specimans were obtained and randomly assigned to eight groups. Dentin surfaces were prepared with one of four cutting types: carbide bur, Er:YAG laser (2 W, 3 W and 4 W) and conditioned with two bonding systems, Scotchbond Multipurpose Plus (SM), Clearfil SE bond (SE) and composite resin-build ups were created. After storage for 24 hours, each specimen was serially sectioned perpendicular to the bonded surface to produce more than thirty slabs in each group. Micro-tensile bond strength test was performed at a crosshead speed of 1.0 mm/min. Micro-tensile bond strengths (${\mu}TBS$) were expressed as means$\pm$SD. Data were submitted to statistical analysis using two-way ANOVA, one-way ANOVA, Student-Newman-Keuls' multiple comparison test and t-test. Results and Conclusion 1. Regardless of bonding systems, the ${\mu}TBS$ according to cutting types were from highest to lowest : 3 W, 2 W, Bur, and 4 W. In addition, there was no significant difference between Bur and 4 W (p<0.001). 2. Regardless of cutting types, SM showed significantly higher ${\mu}TBS$ than SE (p<0.001). 3. Bonding to dentin conditioned with SM resulted in higher ${\mu}TBS$ for 3 W compared to Bur, 2 W, and 4 W. There was no significant difference between 2 W and Bur (p<0.001). 4. Bonding to dentin conditioned with SE resulted in higher ${\mu}TBS$ for 3 W compared to 2 W, 4 W, and Bur. Bur exhibited significant lower ${\mu}TBS$ than all other cutting types. There were no significant differences between 3 W, 2 W and between 4 W and Bur (p<0.001). 5. The ${\mu}TBS$ of laser cutting groups were shown in order from highest to lowest: 3 W, 2 W and 4 W in two bonding systems. There was no significant difference between 2 W and 3 W in SE (p<0.001). : The ${\mu}TBS$ of composite resin bonded dentin was significantly affected by interaction between the cutting type and bonding system. In the range of 2 W-3 W, cavity preparation of the Er:YAG laser seems to supply good adhesion of composite resin restoration no less than bur preparation. In particular, if you want to use the self-etching system, including Clearfil SE bond for the purpose of a simplification of the bonding procedures and prevention of adverse effects by excessive etching, an Er:YAG laser may offer better adhesion than a bur.

• Clinical and Experimental Reproductive Medicine
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• v.34 no.4
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• pp.285-291
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• 2007

Objective: To evaluate the outcomes of in vitro fertilization and embryo transfer (IVF-ET) in women over 40 years of age. Methods: A total of 170 patients (271 cycles) over 40 years of age who underwent IVF-ET at Seoul Women's Hospital (Incheon, Korea) were analyzed in this study retrospectively. The patients were grouped into the women <44 years old group and the women $\geq$44 years old group. Statistical analysis was performed using Student's t-test and Fisher's exact test as appropriate. Results: An overall clinical pregnancy rate per retrieval was 11% (30/271). Of these, clinical miscarriage rate were 33% (10/30) and the overall delivery rate was 7.4% (20/271) per retrieval, respectively. The women $\geq$44 years old group had significantly higher cancellation rate (13% vs. 25%), lower number of retrieved oocytes (6.17$\times$4.62 vs. 4.13$\times$4.07), decreased number of 2PN (4.83$\times$3.61 vs. 3.46$\times$3.12), and reduced embryos for transfer (3.52$\times$1.72 vs. 2.81$\times$1.83) than the women <44 years old group. We found significantly lower clinical pregnancy rate (13.0% vs. 2.1%) and live birth rate (9.0% vs. 0.0%) in the women $\geq$44 years old group than the women <44 years old group. Conclusion: The present study has shown that IVF outcome is seriously impaired in the women $\geq$44 years old.

• Journal of Preventive Medicine and Public Health
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• v.9 no.1
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• pp.1-10
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• 1976

This study was conducted in order to observe some descriptive epidemiological findings and causes of life-long labour force loss in the rural population of Korea, and to consider, on the basis of these observations, some principles of the necessary control measures. The total number of subjects in the study was 27,172, all family members of 4,174 households. The study population was located in the 81 counties, out of a total of 138 counties, where the college students conducted service activities during the summer of 1974. In each village area where these service activities were conducted, one household per student interviewer was randomly selected. Student interviewers were instructed on the contents of the questionnaire prior to the survey. The main contents of the questionnaire form included address, name, sex and age of each family members, and present life-long labour force loss, if any, of each family member. In cases of current labour force loss, the age of onset and causes were recorded. Of the total households surveyed, 8.9% had family members (1-4 in number) with life-long labour force loss. Of the total persons surveyed, the crude prevalence rate for life-long labour force loss was 15.1 per 1,000; and the age-standardized prevalence rates for male and female were 16.3 per 1,000 and 13.4 per 1,000, respectively. The rates, in both sexes, were gradually increased as the ages were increased. The prevalence rates per 1,000, in order, for life-long labour force loss by the causes were 10.2 for senility, 2.4 for impairment of extremities, 1.2 for chronic diseases of internal organs, 0.5 for other conditions of muosculoskeletal system, 0.4 for blindness in both eyes, 0.2 for impairment of spine, 0.2 for psychoses, and 0.1 for epilepsy. Among them the causes of impairment of extremities were stroke, poliomyelitis, accidents, arthritis and injury due to war operation, in that order of higher relative frequency. The frequency ratios by age of onset were also observed by the causes and sex.

• Childhood Kidney Diseases
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• v.3 no.2
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• pp.203-208
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• 1999

Purpose: The information on the change of the relative renal function after operation is essential to set the initial treatment plan in unilateral hydronephrosis. So we analyzed the preoperative and postoperative relative renal function, and observed the functional changes by operation and reliability of the various factors in those changes. Materials and Methods: A retrospective trial was done of 81 patients, 35 ureteropelvic junction(UPJ) obstruction and 46 vesicoureteral reflux(VUR), among 393 patients undergoing operations at our institution from March. 1992 to February. 1997. The patients who had infravesical abnormalities, abnormal contralateral kidney and insufficient research data were excluded. We determined the relative renal functions using DTPA and MAG3 scan in UPJ obstruction and DMSA scan in VUR. The mean observation period after operation was 2.01(0.25-4) years. Results: A. UPJ Obstruction 1. The relative renal function was improved significantly after operation(P=0.0007). 2. The kidneys which have preoperative functions between 20% and 40% improved significantly in relative renal function comparing to the kidneys of the other functions(P=0.0046). B. VUR 1. The renal functions didn't improve significantly after operation(P>0.05). 2. There was no significant factor affecting the prognosis in renal functions. Conclusions: 1. The kidneys with UPJ Obstruction show the difference in functional improvement after operation according to the degree of the preoperative renal function, but more investigations about the exact value are needed. 2. In VUR there was no difference between preoperative and postoperative functions, the theoretical basis on objectives of the operation could be the symptoms or factors except the operation.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.465-473
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• 1995

Background: The prevalence of pulmonary tuberculosis has decreased progressively after the control of the tuberculosis began as national control. But as diabetes, malignancy, immunodeficiency disease recently tend to be increased, the tuberculosis become to the important national health problem. So, this study was designed to observe the state and the change of the prevalence and the clinical status of pulmonary tuberculosis for recent 10 years at one women's university. Method: We retrospectively investigated the epidemiology and the clinical status of 612 patients who were registered at the Ewha Womans University Health Center by analyzing records from 1983 to 1992. Results: 1) The prevalence rate had been steadily decreased from 0.63% in 1983 to 0.11 % in 1992. The prevalence of freshman and the incidence rate according to the entrance year while in the university significantly decreased since 1989. 2) In classifying by registered source, 45.6% of students were detected by annual periodical health examination, 34.5% by entrance physical examination, 12.0% by hospital, 5.4% by health center clinic, 2.5% by reentrance physical examination, sequentially. 3) The students with past history of tuberculosis were 70(11.4%) and 61(10%) suffered from pulmonary tuberculosis. The patients with family history of tuberculosis were 142(23.3%). 4) There were 530(86.6%) with minimal disease, 79(12.9%) with moderate and only 3(0.5%) with far advanced, when classified by the severity of disease. 5) The initial symptoms were mild breathing difficulty in 30.1%, sweating in 14.9%, fatigue in 14.3%, febrile sense in 11.7%, hemoptysis in 8.2%, sequentially. 6) The duration of treatment was $10.6{\pm}3.6$ months in mild group, $14.9{\pm}5.2$ months in the moderate group(P<0.05). 7) The side reactions of the drug were GI trouble in 7.2%, hepatitis in 1.8%, skin rash in 0.8% and streptomycin side in used patients in 9.1%. Conclusion: The prevalence of pulmonary tuberculosis among the students in one women's university was significantly lower than that of university students and 20-24 year-old age group announced in tuberculosis survey on a national scale, and significantly decreased since 1989. The treatment effect was desirable in student's group managed by university health center.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.9 no.2
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• pp.174-179
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• 1998

Objective：Present study investigated the relationship between mothers' self-perception and perception of children's problems. Method：Subjects were 63 children, mothers, who visited child & adolescent psychiatric clinic. Their mothers completed Minnesota Mulpiphasic Personality Inventory(MMPI) & Korean Personality Inventory for Children(KPI-C). Correlation between validity scales of mothers' MMPI and validity scales of KPI-C was analysed, and then we divided subjects into two group(High & Low Group) according to the MMPI validity scales, and compared KPI-C's validity scales by student t-test. Result：There were significant positive correlation(r=.30) between K scale of MMPI and L scale of KPI-C, significant negative correlation(r=-.32) F scale of MMPI and L scale of KPI-C. The Means of T scores did show significant difference according to MMPI F, K scales in KPI-C L scale, to MMPI L scale in KPI-C F scale. Conclusion：These results indicated that defensive mothers tend to perceive her child's problems more defensively. However mothers who exaggerate their problem more severely, do not exaggerate their children's problem. Therefore, these result suggested that we should be careful not to underestimate children's problem whose mother elevated in K scale of MMPI.

• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.2
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• pp.95-103
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• 2020

Purpose: The purpose of this study was to compare the axial displacement of the hexagonal and conical abutment in internal conical connection implant after screw tightening and cyclic loading. Materials and Methods: Internal conical connection implants were divided into two groups (n = 10): group HEX, hexagonal abutment; and group CON, conical 2-piece abutments. The axial displacement and removal torque values were measured after 30 Ncm torque tightening and 250N loading test of 100,000 cycles. The Student t test with 5% significance level was used to evaluate the data. Results: HEX group demonstrated significantly higher axial displacement values after 30 Ncm tightening in comparison to the CON group (P < 0.05). No significant difference was found in axial displacement after cyclic loading (P = 0.052). Removal torque loss before and after the cyclic loading both revealed no significant difference between groups (P = 0.057 and P = 0.138). Removal torque value decreased after cyclic loading in both groups (P < 0.05). Conclusion: Overall, both abutment with or without hexagon index presented similar biomechanical performance except HEX group demonstrated significantly more axial displacement after applying tightening torque.

• Journal of Veterinary Clinics
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• v.27 no.2
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• pp.170-174
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• 2010

With the ease availability of statistical software and powerful computers the application of statistical methods in domestic veterinary journals is on the increase. In parallel with this benefit, statistical errors are not uncommon even in renowned scientific and medical journals. These errors may lead to misinterpretation of the data, thereby, subjected to faulty conclusions. A systematic review of articles published in 8 issues of the Journal of Veterinary Clinics during 2006-2007 was performed to assess the statistical methodology and reporting. Ninety-four (72.9%) articles of the 129 original articles screened included any inferential statistical analysis in the article, including comparison of 3 or more groups (53 or 56.4%), comparison of independent 2 groups (40 or 42.6%), and paired t-test (9 or 9.6%) in order. Of the 94 articles in which statistical analysis was done 62 (or 66.0%) had at least 1 statistical error. Errors included failure to apply or incorrectly applying independent Student's t-test for paired data or vice versa, inappropriate use of t-test for more than 3 groups and failure in chi-square test to consider continuity-correction for small expected frequencies. The common errors in ANOVA were failure to validate assumption of the test, inappropriate post-hoc multiple-comparison and incorrect assumption of independence of data in repeated measures design. Reporting errors included failure to state statistical methods and failure to state specific test if more than 1 test was done. It is suggested that an editorial effort would be necessary to achieve the improvement of appropriate statistical procedures through the publication of statistical guidelines to author(s).

• Clinical and Experimental Reproductive Medicine
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• v.28 no.2
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• pp.79-86
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• 2001

Objective: Mouse pre-antral follicles require the addition of gonadotropins (Gns) to complete maturation and ovulation of oocyte and antrum formation in vitro. However, we tried examination of in vitro growth of mouse pre-antral follicles in medium without Gns and/or phygiological factors. And also, pre-antral follicles were isolated from ovaries by mechanical method. Our present studies were conducted to evaluate on the growth of follicles and intra-follicular oocytes and antrum formation in vitro of mouse pre-antral follicles in two different media. Methods: Pre-antral follicles ($91{\sim}120{\mu}m$) were isolated mechanically by fine 30G needles not using enzymes from ovaries of 3-6 week-old female ICR mice. Isolated pre-antral follicles were cultured in $20{\mu}l$ droplets of TCM (n=17; follicles: $107.8{\pm}1.58{\mu}m$; oocytes: $57.9{\pm}1.2{\mu}m$) or MEM (n=12; follicles: $109.3{\pm}2.53{\mu}m$; oocytes: $55.4{\pm}1.6{\mu}m$) under mineral oil on the 60 mm culture dish. All experimental media was supplemented with 10% FBS without Gns and/or physiological factors. Pre antral follicles were individually cultured for 8 days. Antram formation and growth of pre-antral follicles and intra-follicular oocytes were evaluated using precalibrated ocular micrometer at X200 magnifications during in vitro culture. Results were analyzed using combination of Student's t-test and Chi-square, and considered statistically significant when p<0.05. Results: Antrum formation had started in two culture media on day 2. On day 8, antrum formation had occurred in 58.3% of pre-antral follicles cultured in DMEM, but only in 23.5% of those cultured in TCM (p=0.0364). Growth of pre-antral follicles and intra-follicular oocytes were observed on day 4 and 8. On day 4, follicular diameter was similar (p=0.1338) in TCM ($119.4{\pm}2.58{\mu}m$) and MEM ($125.4{\pm}4.52{\mu}m$). However, on day 8, diameters of pre-antral follicles cultured in MEM ($168.9{\pm}17.29{\mu}m$) were significantly bigger (p=0.0248) than that in TCM ($126.7{\pm}4.28{\mu}m$). On day 4 and 8, diameters of intra-follicular oocytes were similar in TCM ($67.1{\pm}1.3$ and $72.4{\pm}0.9{\mu}m$) and MEM ($65.2{\pm}1.7$ and $73.3{\pm}1.5{\mu}m$), respectively. Conclusion: We can conform that medium without Gns and/or physiological factors can be used for in vitro antrum formation and growth of pre-antral follicles and intra-follicular oocytes in mouse. In conclusion, MEM supplemented with FBS can be used for growth in vitro of mouse pre-antral follicles isolated mechanically.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.3
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• pp.223-227
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• 2002

연구목적: 전반적인 자궁내막증이 체외수정시술에 미치는 영향을 알아보고, 특히 stage III-IV 자궁내막증을 갖는 불임환자 체외수정시술 결과에 대하여 알아보고자 본 연구를 시행하였다. 연구재료 및 방법: 1998년 9월부터 2001년 9월까지 진단복강경을 통해 자궁내막증으로 진단된 환자 중 체외수정시술을 시행 받은 91명 131주기를 대상으로 하였으며 이중 stage III-IV의 자궁내막증을 갖는 환자는 27명 34주기였다. 비교군은 이시기에 진단된 순수 난관원인으로 체외수정시술을 시행한 40명 56주기를 대상으로 하였다. 통계학적 검사는 Student's t-test와 Chi-square test를 시행하였고, p<0.05를 유의성이 있는 것으로 판정하였다. 결 과: 전체 자궁내막증 환자와 난관인자의 체외수정시술에서 두 군간의 나이는 $31.6{\pm}3.3$, $32.6{\pm}3.6$세로 비슷하였다. 채취된 난자의 수 ($10.3{\pm}6.6$ vs $11.7{\pm}5.1$), 성숙난자 수 ($7.4{\pm}4.7$ vs $7.7{\pm}4.9$), 수정율 ($70.2{\pm}32.4%$ vs $73.7{\pm}20.0%$), Good embryo quality rate (8세포 (G1+G2)를 2PN의 개수로 나눈 값) (32.6% vs 32.4%) 및 배아이식 수 ($4.6{\pm}1.4$ vs $4.8{\pm}1.1$)로 두 군간에 차이는 없었다. 또한 임상적 임신율의 경우도 각각 30.7%, 42.8%로 비슷하였다. 중등도 및 중증의 자궁내막증과 난관인자의 비교에서 성숙난자 및 채취된 난자의 개수는 각각 $8.8{\pm}4.9$, $7.7{\pm}3.9$, $11.3{\pm}7.0$, $11.7{\pm}5.1$개로 두 군간에 차이는 없었다. 수정율은 stage III와 IV 군에서 감소되는 경향을 보였으나 통계학적인 유의성은 없었다 ($66.2{\pm}30.0%$ vs $73.7{\pm}20.0%$). Good qulity embryo rate (GQER)는 stage III-IV 자궁내막증 환자군에서 22.0%로 순수 난관인자의 32.4%에 비하여 감소하는 경향을 보였으나 통계학적인 유의성은 없었다 (p=0.15, Chi-square test). 배아이식 수의 경우는 각각 $4.7{\pm}1.5$, $4.8{\pm}1.1$개로 차이가 없었다. 배아이식 주기당 임상적 임신율의 경우는 stage III-IV군에서 25.0% (8/32), 난관인자 군의 42.8% (24/56)로 통계학적인 유의성은 없었으나 (p=0.06, Chi-square test), 중등도 및 중증의 자궁내막증을 갖는 환자에서 임신율이 감소하는 경향을 보였다. 결 론: 체외수정시술시 자궁내막증이 임신율에 나쁜 영향을 미치지 않지만, 중등도 및 중증의 자궁 내막증을 갖는 불임환자의 체외수정시술에서는 임신율에 나쁜 영향을 끼칠 가능성이 있을 것으로 사료된다.