• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.4
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• pp.29-37
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• 1974

Theoretical analysis is carried out for the curtoff wavelength characteristics of rectangular waveguide containing a step-ridge. In order to obtain the cutoff wavelength of step-rigde waveguide, an transmission matriz is formulated by the method of equivalent transverse resonance. The characteristic equation, in which the wavelength is obtainable by the numerical method, is derived from the equation. An approximate determination of the dominant mode fields in step-ridge waveguides at all frequencies has been made. Using these fields, the characteristic impedance equation is derived from power considerations. Analyzing the results of the calculations, the following characteristics are noted. The values of λ /a of TE10 mode increase with decreasing gap lengths and with increasing step width S or S , or both. Experimental results of cutoff characteristics are in good agreement with the theoretical analusis. It is shown that a waveguide within which a step-ridge is placed has a lower cutoff frequency and impedance than empty guide without it. Therefore, the role of a step-ridge guide is to broadening the bandwidth 2 to 3 times more than that of an empty guide of the same demension.

• The Journal of Pediatrics of Korean Medicine
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• v.38 no.2
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• pp.1-10
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• 2024

Objectives This study aimed to assess the reliability and validity of the Five-Visceral Weak Children Questionnaire (FWCQ) in childhood anorexia and to propose optimal cutoff values. Methods We conducted two surveys, spaced one month apart, targeting the parents of 366 children aged 2-9 years who had been diagnosed with anorexia for at least one month. To evaluate the reliability of the FWCQ, we calculated Cronbach's alpha coefficient and employed the test-retest method. Additionally, correlation analysis was performed between the FWCQ and each visceral question, and discriminant validity was assessed by comparing responses from the anorexic and normal groups. Furthermore, we determined the cutoff value of the spleen weak score, which is closely associated with appetite, for the anorexic group. Results The first survey yielded responses from 336 participants, followed by 171 responses in the second survey conducted one month later. The FWCQ demonstrated high internal consistency (Cronbach's alpha = 0.776), and test-retest results were consistent. The correlation coefficients between the FWCQ and each visceral question were all statistically significant. Moreover, significant discriminant validity was observed between the anorexic and normal groups in the FWCQ score and the heart, spleen, and kidney weak scores. The optimal cutoff value for the spleen weak score in the anorexic group was found to be 5.5 points (with a sensitivity of 73.44% and specificity of 66.47%). Conclusions The FWCQ exhibited strong reliability and validity in children with anorexia.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.173-177
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• 2003

Purpose : Recently, different results about factors affecting accurate quantitation of 24-hr urinary protein(24UP) amount using spot urine protein/creatinine ratio(PCR) have been reported. The current study was designed to evaluate correlation between 24UP amounts and PCR in children, and the effect of 24UP amounts, age, sex, and glomerular filtration rate(GFR) on this correlation. Methods : Among 94 patients who visited the department of pediatrics in Busan Paik Hospital from March 2002 to August 2002, 68 patients whose urinary creatinine excretion was ${\geq}15mg/kg/day$ were included in this study. All the patients were divided into I, II/A, B group(I : 24UP<500 mg/day, II : $24UP{\geq}500mg/day$, A : <10 years of age, B : ${\geq}10years$ of age). Pearson correlation analysis was performed between 24UP and PCR to evaluate the relationship. We defined fractional difference between 24UP and PCR, and then performed multiple regression analysis with 24UP amount, age, GFR and fractional difference. Results : There was a strong positive linear correlation between 24UP and PCR(R=0.936, P<0.0001) in all patients, and the correlation was also good in each group. Using PCR cutoff values of 0.5, the PCR provided high sensitivity, specificity, positive and negative predictive value in predicting 24UP amount ${\geq}500mg$. The factors affecting accurate quantitation of proteinuria using spot urine PCR was age, not 24UP amount, GFR or sex. Conclusion : Spot urine PCR is a useful test but has limitations in predicting 24UP amount. Therefore, it should be used only as screening method. Age-adjusted PCR cutoff values may be necessary to predict 24UP amount in children with proteinuria.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.16 no.1
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• pp.14-20
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• 2009

Purpose: The purpose of this study was to identify how accurately body mass index (BMI) and waist circumference (WC) detect obesity in young adult women. Method: Measurements of height, weight, WC, and percent body fat (% BF) were obtained and bioelectrical impedance analysis was used to estimate body fat in 329 female college students. The sensitivity and specificity to screen obesity by BMI and WC were determined using SPSS. Received operating characteristic (ROC) curve analysis was used to assess the appropriate BMI and WC predicting % BF. Results: % BF-defined obesity $(\geq30%)$ had higher prevalence than BMI-defined obesity $(\geq25kg/m^2)$ and WC-defined obesity $(\geq80cm)$. BMI $\geq25kg/m^2$ and WC $\geq80cm$ had high specificity (both, 100%), but low sensitivity (respectively, 13.5% and 22.9%) in detecting % BF-defined obesity. The BMI and WC cutoff values corresponding to % BF-defined obesity were 21.2kg/$m^2$ and 73cm, which were lower than recommended reference values for Korean women. These values decreased specificity but increased sensitivity to detect obesity. The areas under the ROC curve were good (0.84, 0.86) for BMI and WC. Conclusion: BMI and WC have good specificity but miss more than $77\sim86%$ of people with excess fat. Therefore, BMI and WC cutoff values need to be revised and body fat should be considered when screening for obesity in young adult women.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.2
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• pp.218-229
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• 2021

Purpose: Serological tests of tissue transglutaminase (TTG) and deamidated gliadin (DGP) antibodies for celiac disease diagnosis show conflicting correlation with histology in young children and in type 1 diabetes mellitus (T1DM). Tests' ability to predict histology and cutoff values based on age and T1DM was evaluated. Methods: A retrospective study of children who had celiac serological tests between 6/1/2002 and 12/31/2014 at a pediatric hospital. Results: TTG IgA displayed similar results in predicting histology between <4.0 and ≥4.0 years age groups with sensitivity 98% and 93%, and specificity 88% and 86%, respectively. In children <4.0 years old, sensitivity for DGP antibodies was 100% and specificity 94%; in ≥4.0 years age groups, sensitivity was 60%, 88% for DGP IgA and IgG and specificity 95%, 96%, respectively. TTG IgA had low specificity in patients with T1DM compared with non-T1DM, 42% vs. 91%. Positive TTG IgA with normal histology was associated with higher T1DM prevalence at 36% compared with negative tests at 4%. Finally, the TTG IgA cutoff value was higher in T1DM at 36 vs. 16.3 units in non-T1DM. DGP IgG cutoff showed similar values between age groups; TTG IgA and DGP IgA cutoffs were lower in <4.0 years at 8.3 and 11.9 units than ≥4.0 years at 23.4 and 19.9, respectively. Conclusion: TTG IgA is sufficient for the <4.0 years age group and DGP antibodies had no advantage over TTG IgA in older children. The cutoff value to determine a positive TTG IgA should be higher for children with T1DM.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.151-156
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• 2010

Purpose: The liver is the second most common organ injured by blunt abdominal trauma. The purpose of this study was to determine the utility of liver transaminase in screening blunt abdominal trauma patients for traumatic liver injury. Methods: We retrospectively reviewed the medical records of 231 patients who sustained blunt trauma and were at risk for traumatic liver injury between June 2009 and August 2010. All of them underwent a focused assessment with sonography for trauma (FAST) and abdominal computed tomography (CT). Based on the diagnosis of abdominal CT, patients were divided into two groups: group I with liver injury and group II without liver injury. We compared the two groups and calculated the sensitivity, the specificity and the predictive values of serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) by using multiple cutoff values. Results: Of 231 patients with no abdominal free fluid in the FAST, 33 had traumatic liver injury on abdominal CT. The mean AST and ALT levels in group I (311.6 IU/L and 228.1 IU/L, respectively) were significantly higher than the values in group II (48.4 IU/L and 35.6 IU/L, respectively). The cutoff to distinguish liver injury is 60 IU/L for AST and 58 IU/L for ALT, with 93.8% sensitivity and 79.8% specificity for AST, and 90.6% sensitivity and 87.4% specificity for ALT. Conclusion: We recommend that all patient with suspected blunt abdominal trauma be evaluated using serum liver transaminase as a screening test for liver injury even though no abdominal free fluid is shown on the FAST. If AST > 60 IU/L and/or ALT > 58 IU/L, abdominal CT was useful to confirm liver injury in this study.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.1
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• pp.61-68
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• 2021

Objective: This study was conducted to investigate the relationship of semen parameters in samples used for intracytoplasmic sperm injection (ICSI) with fertilization and pregnancy rates in infertile couples. Methods: In this prospective study of Infertile couples with male factor infertility that had undergone ICSI, fractions of the same semen samples obtained for microinjection (to ensure the best predictability) were evaluated to determine the semen parameters and sperm DNA fragmentation index (DFI) on the day of oocyte recovery. Results: In total, 120 couples completed the study and were subdivided into fertilized (n=87) and non-fertilized couples (n=33). The fertilized couples were further classified into pregnant (n=48) and non-pregnant (n=39) couples. Compared to non-fertilized and non-pregnant couples, fertilized and pregnant couples showed statistically significantly higher sperm viability and percentage of normal sperm morphology, as well as significantly lower sperm DFI values. A receiver operating characteristic curve analysis of data from the 120 ICSI cycles showed that sperm viability, normal sperm morphology percentages, and sperm DFI were significant prognostic indicators of fertilization at cutoff values of 40%, 7%, and 46%, respectively. A sperm DFI of 46% showed sensitivity and specificity of 95% and 90%, respectively, for predicting fertilization, and no clinical pregnancies occurred in couples with a sperm DFI above 46%. Conclusion: Semen parameters from the ICSI day sample, especially sperm viability, normal morphology, and DFI, had an impact on fertilization and pregnancy outcomes in ICSI cycles.

• Journal of Veterinary Science
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• v.25 no.3
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• pp.37.1-37.10
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• 2024

Importance: The portal vein to aorta (PV/Ao) ratio is used to assess the clinical significance of extrahepatic portosystemic shunt (EHPSS). Previous studies using computed tomography (CT) were conducted in dogs but not in cats. Objective: This study aimed to establish normal reference values for PV indices (PV/Ao ratio and PV diameter) in cats and determine the usefulness of these for predicting symptomatic EHPSS. Methods: This study included 95 dogs and 114 cats that underwent abdominal CT. The canine normal (CN) group included dogs without EHPSS. The cats were classified into feline normal (FN, 88/114), feline asymptomatic (FA, 16/114), and feline symptomatic (FS, 10/114) groups. The PV and Ao diameters were measured in axial cross-sections. Results: The group FN had a higher PV/Ao ratio than the group CN (p < 0.001). Within the feline groups, the PV indices were in the order FN > FA > FS (both p < 0.001). The mean PV diameter and PV/Ao ratio for group FN were 5.23±0.77 mm and 1.46±0.19, respectively. The cutoff values between groups FN and FS were 4.115 mm for PV diameter (sensitivity, 100%; specificity, 97.7%) and 1.170 for PV/Ao ratio (90%, 92.1%). The cutoff values between group FA and FS were 3.835 mm (90%, 93.8%) and 1.010 (70%, 100%), respectively. Conclusions and Relevance: The results demonstrated significant differences in PV indices between dogs and cats. In cats, the PV/Ao ratio demonstrated high diagnostic performance for symptomatic EHPSS. The PV diameter also performed well, in contrast to dogs.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4933-4938
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• 2014

Background: Although various tumor markers have been utilized in management of stomach cancer (SC), only a few reports have described relevance of examples such as CYFRA 21-1 and neuron-specific enolase (NSE). The purpose of this study was to evaluate the potential diagnostic performance of carcinoembryonic antigen (CEA), CA 19-9, CA72-4, CYFRA 21-1 and NSE in patients with SC. Materials and Methods: Ninety-six SC patients with pathologic confirmation between 2012 and 2013 were enrolled. Serum levels of five tumor markers were analyzed using a solid-phase immunoradiometric assay. Receiver operating characteristic (ROC) curves were plotted for the five tumor markers to investigate their diagnostic powers and adjusted cutoff values derived from analysis of ROC curves were evaluated to calculate the sensitivity of each for SC with recommended cutoff values. Results: Based on two different cutoff values (recommended and adjusted), CYFRA 21-1 (${\geq}2.0$ and 1.2 ng/ml) had a respective sensitivity of 50% and 78.1%, compared with 8.3% and 18.8% for CEA (${\geq}7.0$ and 3.9 ng/ml), 15.6% and 18.8% for CA 19-9 (${\geq}37$ and 26.7 ng/ml), 28.1% and 9.6% for CA 72-4 (${\geq}4.0$ and 13 ng/ml) and 7.3% and 7.3% for NSE (${\geq}14.7$ and 15.0 ng/ml) in the initial staging of primary SC. The area under the curve (AUC) for CYFRA 21-1, with a value of 0.978 (95% confidence interval, 0.964-0.991) was comparatively the highest. Univariate analysis revealed significant relationships between tumor marker level and lymph node involvement, metastasis and staging with CYFRA 21-1, CA 72-4 and NSE. Conclusions: CYFRA 21-1 was the most sensitive tumor marker and showed the most powerful diagnostic performance among the five SC tumor markers. NSE and CA 72-4 are significantly related to lymph node involvement, metastasis or stage. Further evaluations are warranted to clarify the clinical usefulness and prognostic prediction of these markers in SC.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.3
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• pp.283-292
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• 1996

Objective: To determine the cutoff value of clomiphene citrate challenge test(CCCT) that can predict the normal and abnormal(diminished) ovarian response group and to assess the usefulness of CCCT as a predictor of ovarian reserve. Materials and Methods: From March 1994 to Februry 1996, CCCT was performed to 129 infertile patients and among them, 20 patients whose basal FSH on the third day of menstrual cycle was more than 20 mIU/ml were excluded. At the same time, the same CCCT was performed to the fifteen healthy volunteers with proven fertility to determine the cutoff value of CCCT. Results; 1) A FSH value higher than 23.4 mIU/ml, measured on the 10th day of menstrual cycle, was defined as a abnormal ovarian response. The cutoff value of 23.4 mIU/ml is more than 2 standard deviations(SD) above the mean value of 15 healthy women after CCCT. 2) The abnormal CCCT group, the subpopulation with a FSH value of 23.4 mIU/ml or more, was 7.3%(8/109) and their mean age was higher than the normal CCCT group($36.5{\pm}4.5$ vs. $32.9{\pm}4.8$, P = 0.059). And the percentage of the patients older than 35 years of the abnormal CCCT group was significantly higher than that of the normal CCCT group(62.5% vs. 38.6%, p <0.05). 3) There was no correlation between the hormone values of the third day and the 10th day of menstrual cycle before and after CCCT except between FSH of the third day and the 10th day. Conclusion: The CCCT is a good method to predict the individual ovarian response to COH for ART, especially in the patients who has no other abnormal findings that predict poor prognosis. And it is neccessary to determine the cutoff value of CCCT by the large numbers of randomized study, and combining the previously proven prognostic factors, it can be applicated in many individual centers for evaluate the ovarian response before ART program.