• Journal of Oriental Neuropsychiatry
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• v.29 no.2
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• pp.69-77
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• 2018

Objectives: To determine the relationship between 2D:4D ratio and Minnesota Multiphasic Personality Inventory-2 Questionnaire (MMPI-2 scales). Methods: The 2D:4D ratio in 101 Korean medical students was measured. MMPI-2 test was performed. Results: In the unisex group, there were significantly positive correlations between the 2D:4D ratio and MMPI-2 scales of Hs, D, Pt, Sc, Si, RC1, RC2, RC8, INTR, ANX, OBS, HEA, BIZ, LSE, WRK, TRT, A, R, Mt, PK, and AAS while there were significantly negative correlations between the 2D:4D ratio and MMPI-2 scales of Es and Do. In the male group, there were significantly positive correlations between the 2D:4D ratio and MMPI-2 scales of Hs, RC1, RC8, HEA, and AAS while there were significantly negative correlations between the 2D:4D ratio and MMPI-2 scale of AGGR. In the female group, the 2D:4D ratio showed significantly positive correlations with MMPI-2 scales of Pt, Sc, Si, RC1, RC2, RC6, INTR, DEP, BIZ, LSE, WRK, A, Mt, PK, and Ho while it showed significantly negative correlations with MMPI-2 scale of Do. Conclusions: MMPI-2 scales are correlated with the 2D: 4D ratio. Therefore, 2D: 4D ratio could be used as an indicator to reflect multiphasic personality of individuals.

• Korean Journal of Biological Psychiatry
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• v.17 no.3
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• pp.136-144
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• 2010

Objectives : The $2^{nd}$ to $4^{th}$ digit length(2D : 4D) ratio reflects the amount of exposure and sensitivity to the prenatal sex hormone and it is considered to be the most convenient and useful way to understand the influence of sex hormone in the determination of human behavioral traits. This study was carried out to find the correlation between the 2D : 4D ratio and characteristics of temperament and character in Korean university students. We assumed that 2D : 4D ratio would show a strong correlation with temperament which is defined to be an inclination of an automatical emotional response to a stimulus. Methods : Participants were 104 university students who completed 2 self-report measures : Temperament and Character Inventory(TCI), Temperament Test. We examined the 2D : 4D ratio of each subject by measuring the lengths of the $2^{nd}$ and $4^{th}$ fingers using a photocopy measurement. We performed statistical analyses using correlation test and t-test to examine the relationship between 2D : 4D ratio and psychological characteristics. Results : We found out the typical sex difference in 2D : 4D ratio. Women had significantly higher 2D : 4D ratio than men. TCI-Character factor(TCI-C) didn't show any significant correlation with the 2D : 4D ratio. TCI-Tempterament factor(TCI-T) and the item of Temperament Test showed a significant correlation with the 2D : 4D ratio. In correlation analysis of the total group including all women and men, the 2D : 4D ratio showed a significant positive correlation in a subscale(shyness with stranger) of harm avoidance scales in TCI-T. In correlation analysis of women's group, the 2D : 4D ratio showed a significant positive correlation in two subscales( fear of uncertainty) and[shyness to stranger] of harm avoidance scales in TCI-T. In correlation analysis of men's group, the 2D : 4D ratio showed a significant negative correlation with a sanguine temperament item of the Temperament Test. Conclusion : The results suggest that the amount of exposure to sex hormone in the prenatal period seems to have an impact on the determination of temperament and characteristics.

• Journal of Korean Medicine for Obesity Research
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• v.10 no.1
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• pp.41-48
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• 2010

Background The length of the second digit (the index finger) relative to the length of the fourth digit (the ring finger) is sexually dimorphic as males have a lower second to fourth digit ratio (2D:4D). There is evidence that sex differences in 2D:4D arise from in utero concentrations of sex steroids, with a low 2D:4D (male typical ratio) being positively related to prenatal testosterone, while a high 2D:4D (female typical ratio) is positively associated with prenatal oestrogen Objective To investigate possible associations between 2D:4D ratio and sexually dimorphic body composition Methods 2D:4D ratio, body mass index (BMI), waist circumference, waist-hip ratio (WHR), weight, and body fat percentage was measured from 46 men and 20 women Results Digit ratio was found to be significantly lower in men than in women. No significant correlation between 2D:4D ratio and body compositions was found for both men and women while digit ratio in obese men was significantly higher than normal weight men. Conclusion This finding dose not support the significant correlation between digit ratio and sexually dimorphic body composition. However digit ratio in obese men was significantly higher than normal weight men.

• Korean Journal of Biological Psychiatry
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• v.18 no.1
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• pp.25-35
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• 2011

Objectives : Cerebral laterality is thought to be an important marker for neurodevelopment. Prenatal testosterone could influence both cerebral laterality and 2nd to 4th finger length ratio(2D : 4D). EEG coherence and 2D : 4D were examined to investigate the relationship between prenatal testosterone level and cerebral laterality. Methods : EEG was recorded in 24 healthy subjects in the eyes closed resting state. Differences in 2D : 4D finger ratio were used to discriminate "masculine finger type" and "feminine finger type" groups. The 2D : 4D ratio was lower and greater than one for the "masculine finger type" group and "feminine finger type" group, respectively. We used coherence analysis to estimate the cortical functional connectivity. Results : There were statistically meaningful relationships among cerebral functional connectivity, sex and finger ratio. Man and masculine finger type group showed higher intra-hemispheric coherence than those of woman and feminine finger type group. Woman and feminine finger type group showed higher inter-hemispheric coherence than those of man and masculine finger type group. Conclusions : These results imply that prenatal testosterone might act as important determinants of cerebral laterality. Further examination of the relationship between 2D : 4D and EEG coherence in schizophrenia could give some clues for the neurodevelopmental hypothesis of schizophrenia genesis.

• Journal of Oriental Neuropsychiatry
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• v.28 no.3
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• pp.157-164
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• 2017

Objectives: The purpose of this study is the research of the 2D:4D ratio and its correlation with the Sasang constitution and the MBTI preference types. Methods: A measurement of the 2D:4D ratios of 101 South Korean medical students was performed, the QSCC-II and PSSC-2004 were used to diagnose the Sasang constitution, and MBTI testing was performed to classify the preference types. Results: In the relationship between the Sasang constitution and the 2D:4D ratios, a statistically significant difference is absent in the 2D:4D ratios of the group comprising both sexes in the order of Taeumin, Soyangin, and Soeumin. A statistically significant difference is also lacking in the 2D:4D ratios of the male-only group in the order of Taeumin, Soyangin, and Soeumin. The 2D:4D ratios are higher in the female group only, but again a statistically significant difference is absent. In the 2D:4D ratios according to the MBTI preference type, the 2D:4D ratios of the I, S, F, and P types are higher in the unisex group, but a significant difference is not evident. The 2D:4D ratios of the E, N, F, and P types are higher in the male-only group, but again a significant difference is not evident. In the female-only group, the mean of the 2D:4D ratios of the I, S, F, and P types is higher, but a significant difference is not identifiable. Conclusions: The Sasang constitution and the MBTI preference types did not show statistically significant differences regarding the 2D:4D ratios of the male, female, and unisex groups.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2170-2177
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• 2012

The ratio of index finger length to ring finger length(2D:4D) is an index of prenatal testosterone and/or estrogen exposure. The aim of this study is to investigate digit ratio and the type of gender-role orientation, to identify the correlation between 2D:4D and gender-role orientation in health and medical students. Participants were 120 male and 146 female university students majoring in health or medicine. After filling in KSRI(Korean Sex Role Inventory), 2nd and 4th finger lengths were measured on both hands using vernier callipers with photocopy. This study showed 2D:4D in the males was 0.95, and that in the females was 0.96 (p<0.01). 38.3% male students revealed androgyny, on the other hand, 35.6% female students revealed undifferentiated type from KSRI. And also, there was a significant difference in masculinity score between male and female but not in feminity score. There was no significant difference in 2D:4D according gender role orientation. The KSRI masculinity score was negatively related to 2D:4D of left hand in male (p<0.05). The results of this study suggest that a more masculine gender role orientation in males is associated with low 2D:4D revealing higher testosterone and/or lower estrogen level in utero. However, more research in 2D:4D ratio to Korean is needed for support of this result.

• Journal of the Korean Data and Information Science Society
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• v.23 no.6
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• pp.1145-1154
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• 2012

Recent research has been mostly focused on the differences of prenatal sex hormone could affect the ratio of the lengths of the second to fourth digits (2D:4D) as well as the rate of several physiological characteristics. It has been suggested that digit ratios are thought to be associated with either higher prenatal testosterone levels or greater sensitivity to androgens, or both. However, a study of person with disabilities are rare in Korea. The purpose of this study was to compare patterns of the ratio (2D:4D) of the lengths of the second and fourth digits in persons with disabilities and students without disabilities. Also, we empirically analyze the characteristics of persons with disabilities. We found that finger length ratio (2D:4D) of men with disabilities and student without disabilities were lower than women with disabilities and student without disabilities. Therefore, it could be confirmed that finger length ratio (2D:4D) is sexually dimorphic trait. There were no correlations between finger length ratio (2D:4D) and age group in persons with disabilities. Therefore, as with person without disabilities, the 2D:4D ratio was negatively associated with a growth process of persons with disabilities. Finally, There was no difference correlations between finger length ratio (2D:4D) and level of disability in persons with intellectual disabilities. From this, one possible explanation for this is that if finger length ratio (2D:4D) is related to person with disability then current classification of the level of disability deserves further investigation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3983-3990
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• 2012

The hazardous effects of heavy alcohol intake and smoking to body systems have been identified by numerous studies, and there is many influencing factors on alcohol intake and smoking choices. The aim of this study is to identify the correlation between alcohol intake and digit ratio (2D:4D), as well as smoking and digit ratio (2D:4D) in university students. Participants were 121 male and 314 female university students. After filling in questionnaire related alcohol and smoking history, 2nd and 4th finger lengths were measured on both hands using vernier callipers with photocopy. This study showed 2D:4D of the males was 0.95, and that of the females was 0.96. There was a significant difference between male and female in digit ratio. The digit ratio according alcohol intake level significantly differed in only women's left hand. The digit ratio according smoking level significantly differed in only men's left hand. Moreover, The digit ratio was negatively associated with alcohol intake and smoking. The results of this study suggest that the digit ratio (2D:4D) affected with fetal testosterone concentration is negatively related to alcohol intake and smoking. Therefore, the digit ratio would be used in preventive program of alcohol intake and smoking of adolescent, or in antialcoholism /smoking cessation program as a biological basic data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1245-1251
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• 2013

The aim of this study is to identify characteristics of 2D:4D according to type of handedness. Data was collected from October, 4th, 2010 to April, 30th, 2012. After handedness assessment, 2nd and 4th finger length were measured by vernier calipers. This study showed remarkable gender difference of 2D:4D in left hand for left handers and right hand for right handers, However, there was no significant difference according to type of handedness in each gender. The correlation between left and right 2D:4D in males right handedness was higher than that of male left handedness, otherwise, in case of female, that of left handedness was higher than that of right handedness. The results of this study suggest that the 2D:4D of left handedness does not differ from that of right handedness, however, gender difference and correlation between left and right 2D:4D show different characteristics according to handedness.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.2
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• pp.154-159
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• 2015

This paper deals with the effect of concrete target size on penetration of projectiles. We investigated the penetration depth and residual velocity of projectiles using the 2-D axial symmetric model. Most analysis were conducted with 13 kg projectile (striking velocity: 456.4 m/s) and concrete target with compressive strength of 39 MPa. This paper provided penetration depth (or residual velocity) versus ratio D/d (target diameter, D and projectile diameter, d). When the bottom of concrete cylinder was constrained, penetration depth converged to limit depth more than the ratio D/d of 36. The residual velocity of projectile with thin concrete target were investigated. The residual velocity was converged to specific velocity more than the ratio D/d of 16.