• Imaging Science in Dentistry
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• v.50 no.4
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• pp.323-330
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• 2020

Purpose: The mastoid region is ideal for studying sexual dimorphism due to its anatomical position at the base of the skull. This study aimed to determine sex in the Iranian population based on measurements of the mastoid process using different data mining algorithms. Materials and Methods: This retrospective study was conducted on 190 3-dimensional cone-beam computed tomographic (CBCT) images of 105 women and 85 men between the ages of 18 and 70 years. On each CBCT scan, the following 9 landmarks were measured: the distance between the porion and the mastoidale; the mastoid length, height, and width; the distance between the mastoidale and the mastoid incision; the intermastoid distance (IMD); the distance between the lowest point of the mastoid triangle and the most prominent convex surface of the mastoid (MF); the distance between the most prominent convex mastoid point (IMSLD); and the intersecting angle drawn from the most prominent right and left mastoid point (MMCA). Several predictive models were constructed and their accuracy was compared using cross-validation. Results: The results of the t-test revealed a statistically significant difference between the sexes in all variables except MF and MMCA. The random forest model, with an accuracy of 97.0%, had the best performance in predicting sex. The IMSLD and IMD made the largest contributions to predicting sex, while the MMCA variable had the least significant role. Conclusion: These results show the possibility of developing an accurate tool using data mining algorithms for sex determination in the forensic framework.

• The korean journal of orthodontics
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• v.53 no.3
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• pp.185-193
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• 2023

Objective: The growth and development of the mandible strongly depend on modeling changes occurring at its ramus. Here, we investigated covariance patterns between the morphology of the ramus and the rest of the face. Methods: Lateral cephalograms of 159 adults (55 males and 104 females) with no history of orthodontic treatment were collected. Geometric morphometrics with sliding semi-landmarks was used. The covariance between the ramus and face was investigated using a two-block partial least squares analysis (PLS). Sexual dimorphism and allometry were also assessed. Results: Differences in the divergence of the face and anteroposterior relationship of the jaws accounted for 24.1% and 21.6% of shape variation in the sample, respectively. Shape variation was greater in the sagittal plane for males than for females (30.7% vs. 17.4%), whereas variation in the vertical plane was similar for both sexes (23.7% for males and 25.4% for females). Size-related allometric differences between the sexes accounted for the shape variation to a maximum of 6% regarding the face. Regarding the covariation between the shapes of the ramus and the rest of the face, wider and shorter rami were associated with a decreased lower anterior facial height as well as a prognathic mandible and maxilla (PLS 1, 45.5% of the covariance). Additionally, a more posteriorly inclined ramus in the lower region was correlated with a Class II pattern and flat mandibular plane. Conclusions: The width, height, and inclination of the ramus were correlated with facial shape changes in the vertical and sagittal planes.

• Anatomy and Cell Biology
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• v.57 no.2
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• pp.221-228
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• 2024

Although studies of the sacral corridor dimension have been reported in the European population, little attention has been paid to this issue in the Asian population. The purpose of the study is to estimate the safe dimension of the corridor to avoid neurovascular damage during the fixation of the sacral fracture. The study aimed to examine the cephalocaudal (vertical) and the anteroposterior diameter of the bony passage in the upper three sacral segments. The study further examines the effect of age and sex on corridor dimensions at different sacral levels. Three-dimensionally reconstructed sacra from computed tomography of normal subjects were included in the study. Cephalocaudal and anteroposterior diameters were measured in coronal and axial sections using Geomagic Freeform Plus software. Anteroposterior diameter of the sacral corridor at the first, second, and third sacral segments are significantly higher in males (P=0.013, 0.0011, and <0.0001, respectively). The length of the sacrum also revealed sexual dimorphism (P<0.00016). The anteroposterior diameter of the second sacral segment (ap-S2c) correlated moderately with the first sacral anteroposterior diameter (ap-S1c) (R=0.519, P<0.001). The ap-S2c exhibited a moderate correlation to the third sacral segment (ap-S3c) (R=0.677, P<0.001). The sacral corridor at the level of S1 has the largest cephalocaudal (18.25 mm) and anteroposterior diameter (17.11 mm). Placement of the screw in the first sacral corridor may avoid damage to the neurovascular bundle during the fixation of the sacral fracture.

• Anatomy and Cell Biology
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• v.57 no.2
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• pp.213-220
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• 2024

The jugular foramen (JF) is located between the temporal and occipital bones. The JF is a primary pathway for venous outflow from the skull and passage of nerves. Variations are common in this region and may have clinical and surgical implications. To analyze the sexual dimorphism and JF morphology in skulls from Northeastern Brazil. 128 human skulls from the Anatomy Laboratory of the Federal University of Paraíba, 64 male and 64 female, were selected and the JFs analyzed for bone septation and the presence of a dome. Data analysis considered P<0.05 as significant. On at least one side, complete septation was observed in 26 skulls (20.3%), incomplete septation in 93 skulls (72.6%) and 61 skulls (47.6%) did not present septation. In 114 skulls (89%), 47.6% female and 41.4% male, have a unilateral presence of the dome and 71 (55.4%) have it bilaterally. Posterolateral compartment diameters and JF area had higher values on the right side in the total sample and separated by sex (P<0.05). Most morphometric variables of the anteromedial compartment were higher in male than in female (P<0.05), fact that was not observed in the posterolateral compartment (P>0.05). This study showed a higher prevalence of complete septation in males compared to females. Morphometric analysis presented a peculiar morphology of the JF in this study. These results suggests that the surgical approach to diseases that affect the JF may be peculiar to the studied population, confirming the importance of morphological analysis of the skull base.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.277-286
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• 2006

Population ecology of Cobitis tetralineata was examined at Churyeong Stream, Seomjin River, Korea. C. tetralineata inhabited on the sand bottoms with $10{\sim}20cm/see$ in current velocity, and $30{\sim}150cm$ in water depth. This species was active on the sand during the daylight hours from March to October, but they hibernated in the inside of the sand during the winter season. Sex ratio of female to male was 1:0.57, and female was $20{\sim}30mm$ (TL) larger than male. The age group of C. tetralineata (female) population showed that the $20{\sim}40mm$ group is 0+ years old, the $45{\sim}65mm$ group 1+ years old, the $65{\sim}90mm$ group 2+ years old, and the group longer than 90 mm over 3 years old. Males $13{\sim}14$ months old after hatching had lamina circularis at the base of its pectoral fin as a secondary sexual character. And in its spawning season, lateral color pattern of male was changed as a sexual dimorphism. The spawning season may be from late June to middle July, $22{\sim}26^{\circ}C$ water temperature. The average number of mature eggs in ovary was about $1,288{\pm}583(474{\sim}2,976)$, egg diameter was about $0.98{\pm}0.1mm$. C. tetralineata fed mainly on Chironomidae, Arcellidae, Branchioda and Algae. The feeding rate was the highest in April and September, but they did not fed in the winter.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.542-549
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• 2014

This study was conducted to investigate the body size, sexual size dimorphism (SSD), and related environmental factors between Red-tongued viper snakes (Gloydius ussuriensis) inhabiting two different places, i.e., Jeju Island and its islet Gapado, and to provide data required to maintain species diversity from May, 2006 until June, 2009. The snout-vent length of the Red-tongued viper snake population inhabiting Jeju Island was found to be 242-532 mm ($422.0{\pm}46.7mm$, n = 100) in females and 296-580 mm ($434.5{\pm}51.7mm$, n = 63) in males. In contrast, the snout-vent length was observed to be 205-395 mm ($335{\pm}43.6mm$, n = 55) in female and 215-430 mm ($328{\pm}39.4mm$, n = 73) in male Red-tongued viper snakes inhabiting Gapado. These data demonstrated the snout-vent length of both female and male Red-tongued viper snakes on Jeju Island to be larger than those on Gapado (Female t = 17.343, df = 115, P<0.001; Male = 19.128, df = 101, P<0.001). SSD was measured to be -0.03 in the Red-tongued viper snake population on Jeju Island, with more or less larger sizes in the males, while it was 0.02 in the Red-tongued viper snake population in the Gapado, with a little larger sizes in the females. The reason for this difference in the snake populations between Jeju Island and Gapado may be due to adaption to the different ecological environments. In addition, as SSD, the snout-vent length of the Red-tongued viper snake populations and in young vipers was somewhat higher in the males than in the females on Jeju Island (t = -2.011, df = 117, P<0.05). However, no significant differences were observed in the snout-vent length of the young and the general Red-tongued viper snake populations on Gapa Island. For the population on Jeju island, the head length (F = 6.318, $df_{1,2}$=1,117, P<0.05), head width (F=8.090, $df_{1,2}$=1,117, P<0.01), inter eye length (F=15.898, $df_{1,2}$=1,117, P<0.001), and tail length (F=238.488, $df_{1,2}$=1,111, P<0.001) were all larger in the males, while females showed higher body mass (F=64.111, $df_{1,2}$=1,114, P<0.001). In the case of the Gapa Island population, no significant differences in the head length, head width, and inter eye length between females and males were observed, while the males had a longer tail length (F=168.555, $df_{1,2}$=1,74, P<0.001) and the females were heavier (F=17.812, $df_{1,2}$=1,76, P<0.001). Though no significant differences were found in the head length, head width, and inter eye length, the tail length (F=67.793, $df_{1,2}$=1,72, P<0.001) and body mass (F=4.558, $df_{1,2}$=1,72, P<0.05) were higher in the young male Red-tongued viper snakes than in the females. The snout-vent length, head length, head width, and inter eye length, which did not display SSD in the young Red-tongued viper snake populations, were higher in the male Red-tongued viper snake populations than in the female population from Jeju Island, implying that SSD in the Red-tongued viper snake population on Jeju Island is expressed due to environmental effects during their growth.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.185-199
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• 1999

The purpose of the present study was to investigate craniofacial patterns in Korean male and female adults, and to compare morphologic differences between different facial types. In order to get configurational groupings, standardized lateral and P-A cephalograms of 174 Korean adults were measured and analyzed with seven angular, nineteen linear, four ratio, and two index measurements. Ward's minimum variance cluster analysis was employed to divide the sample into groups having similar craniofacial morphology, and thereafter, inductive statistics(t-test) was used to characterize morphologic differences of the divided groups. And also, Pearson correlation coefficients were calculated to assess correlation between the cranial dimensions and upper/lower anterior facial height(UAFH, LAFH) in each facial types for both male and female The results were as follows; 1. There existed sexual dimorphism in most of variables except SN-FH angle, palatal plane angle, facial axis angle, facial index, lower anterior facial height ratio and upper facial height ratio. 2. A brachycephalic headform ($0.84{\pm}0.05$) with leptoprosopic facial form ($0.92{\pm}0.05$) was appeared in male, and a mesocephalic headform ($0.86{\pm}0.06$) with leptoprosopic facial form ($0.92{\pm}0.04$) was exhibited in female. 3. Facial types in both male and female subjects were divided into two groups, Group A (mesoprosopic facial type) and Group B (leptoprosopic facial type). The morphologic differences between Group A and Group B were as follows: a. Cranial measurements including index, angular and linear measurements were not found to be different between Group A and Group B in both sexes. b. Increased UAFH, LAFH, and upper/lower anterior dental heights were exhibited in Group Bs of both male and female. c. In both male and female, ramus height and mandible length showed no difference between Group A and Group B. However, genial angle was found to be larger in Group B than Group A. Therefore, the morphologic differences between two groups in male and female were closely related to less favorable anatomic morphology of the mandible. 4. LAFH and UAFH showed no relationships with cranial dimensions in male and female.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.532-542
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• 2007

The purpose of study was to review the transition of dentition according to the evolution of man to know the background of the dental problems like hypodontia and malocclusion. Man is Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Primates, Suborder Haplorrhini, Superfamily Hominoidea, Family Hominidae, Genus Homo, Species Sapiens by taxonomy. The first hominid was Australopithecus which appeared c. 4 millions of years ago and showed bipedalism and distinct dentition. Homos began with H. habilis who appeared c. 2.5 millions of years ago and made stone tools, and then H. erectus and H. neanderthalensis appeared and disappeared until H. sapiens came. The dental formula of primitive mammalians which was I3 C1 P4 M3 changed to I2 C1 P4 M3 of primitive primates, to I2 C1 P3 M3 of Haplorrhini, and to I2 C1 P2 M3 of hominoids. That of H. sapiens is changing to I2 C1 P2 M2.The box type dentition of hominoids changed to the omega type dentition of Australopithecus, and to the parabolic type of H. sapiens. The size of teeth decreased continually, especially the canine and sexual dimorphism. The dentition moved backward and downward to the cranial crown according to the increase of the brain and decrease of the jaws. It was suggested that the change of diet to the starchy foods, food processing, and the development of cooking reduced the necessity of mastication and caused the change of dentition. The future of H. sapiens who is quite a new species in the earth histroy and is now causing the mass extinction of other species is hard to see. It seems that hypodontia and malocclusion are related to the dentition change according to the evolution of man and is likely to increase.

• Korean Journal of Biological Psychiatry
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• v.24 no.3
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• pp.142-148
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• 2017

Objectives The ratio of second to fourth digit length (2D : 4D) could be a potential epigenetic marker of sexual dimorphism reflecting prenatal testosterone exposure. Testosterone is known to affect the development of the brain through an epigenetic mechanism. The purpose of this study was to investigate the effects of exposure to fetal testosterone on the metabolic syndrome based on 2D : 4D of schizophrenia patients and the relationship with the age of onset of schizophrenia. Methods A total of 214 schizophrenia patients participated in this study. The participant's physical and blood tests were performed according to the American National Cholesterol Education Program's Third Amendment of the Metabolic Syndrome Diagnostic Criteria, and the 2D : 4D was measured by the method designed by McFadden. Data were statistically analyzed by t-test, Pearson's correlation analysis and multiple regression model analysis. Results 2D : 4D was significantly higher in female than male in both hands, and there was a statistically significant negative correlation between 2D : 4D and the age of onset of schizophrenia in male. However, 2D : 4D did not show statistically significant correlation with metabolic factors. Conclusions Fetal testosterone suggests the possibility of affecting the age of onset of schizophrenia through the epigenetic mechanism, but there is no clear relationship with metabolic factors.

• Applied Microscopy
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• v.39 no.2
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• pp.157-165
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• 2009

Here we demonstrate the fine structural characteristics of the spigots on the cribellum and its peculiar sieve-like structure at the aspects of the functional significance. The surface of the cribellum is covered by hundred of tiny spigots which producing numerous cribellate silk fibrils. It has been known that the cribellar silk is considered as a quite different sort of catching silk with dry-adhesive properties. By our fine structural observation using the field emission scanning electron microscopy (FESEM), the titanoecid spiders have a specialized sieve-like plate just in front of the anterior spinnerets. The other types of the silk spigots were identified as follows: ampullate, pyriform and aciniform glands. Two pairs of major ampullate glands send secretory ductules to the anterior spinnerets, and another 1~2 pairs of minor ampullate glands supply the median spinnerets. In addition, the pyriform glands send ductules to the anterior spinnerets, and the aciniform glands feed silk into the median and the posterior spinnerets, respectively. Characteristically, 2 distinct types (A & B types) of the aciniform spigots were identified in this spider, and the spigots of the aciniform B type are always detected at the posterior spinneret, however sexual dimorphism for spigot is unlikely to be exhibited in this species of spider.