• Applied Microscopy
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• 제31권4호
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• pp.367-374
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• 2001

Salsoloid Kranz구조를 지닌 다육질성의 Salsola komaravii의 두 단계 잎의 광합성 엽육조직에 대하여 LM 및 TEM에 의한 구조적 분화발달 양상을 연구하였다. 수분저장조직을 둘러싸는 내부 유관속세포층 및 외부 엽육세포층으로 구성된 두 층의 광합성조직은 어린 잎에서는 연결되어 발달하나 성숙한 잎에서는 불연속적으로 발달하였다. 중앙의 유관속 외 다수의 미세맥들은 대개 내부 유관속세포층과 접하여 형성되며 발달초기에는 이 두 세포층의 구조적 차이는 뚜렷하지 많았다. 이들 엽육조직이 신장 발달하면 franz구조 내 내부 유관속 세포층과 외부 엽육세포층은 세포형태, 세포소기관의 분포, 엽록체의 내부 특성, 세포벽의 비후, 원형질연락사의 발달양상 등에서 현저한 차이를 보이며 구조적으로 분화하였다. 특히 이들이 지닌 엽록체의 미세구조 및 원형질 연락사 등의 특성은 생화학적으로 알려진 NADP-ME 유형과 거의 일치하였다. 이들은 세포특이성을 나타내는 C-4 광합성 효소의 발현양상을 조사하는 세포 면역화학법과 접목되어 연구될 것이다.

• 한국어류학회지
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• 제12권3호
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• pp.186-191
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• 2000

충청북도 청원군 가덕면의 무심천 수역에 서식하는 Abbottina springeri를 대상으로 1995년 3월에서 11월에 걸쳐 생태학적 연구가 수행되었다. 물이 정체되고 하상이 뻘과 모래로 이루어진 곳에 주로 서식하였으며 전장 60 mm 이상의 개체는 유속이 완만한 여울에서도 상당수 채집되었다. 6월 개체군의 전장 분포를 보면 30~50 mm 군은 만 1년생, 50~65 mm군은 만 2년생, 65 mm 이상의 군은 만 3년생으로 추정되었다. 이차 성징은 추성, 혼인색, 생식공돌기에서 나타났으며 전장 55 mm 이상의 개체에서 5~6월에 가장 뚜렷하였다. 산란성기는 수온이 $20\sim25^{\circ}C$가 되는 6월이었으며 산란은 만 2년생부터 시작되었다. 암컷과 수컷의 성비는 1:0.93이 었으며 평균 포란수는 652개, 알의 직경은 $0.43{\pm}0.06mm$이였다. 소화관 내용물에는 조류가 가장 많은 비율을 차지하였으며 원생동물은 여름철에 많이 나타나고 전장 60 mm 이상의 큰 개체는 수서곤충도 섭식하고 있었다.

• Animal cells and systems
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• 제6권1호
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• pp.45-51
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• 2002

We compared the complete mitochondrial cytochrome b gene sequences of Korean and European cobitids to provide independent evidence for assessment of systematic and biogeographic relationships of species in the genus Cobitis. The data suggested monophyly of the genus Cobitis and the inclusion of Korean Cobitis species within the group having one lamina circularis, a primitive condition. Also, all the phylogenetic analyses using maximum parsimony, maximum likelihood, and neighbor joining methods showed a monophyletic relationship among Cobitis. The basal position of the Caspian C. cf. sibirica reported here reflects the eastern Asiatic origin cf. the European Cobitis and establishes C. cf. sibirica as an independent lineage. The Korean C. pacifica diverged next to C. cf. sibirica in basal group from the genus Cobitis. This result is in agreement with the hypothesized Asiatic origin of some European freshwater fish lineages. The phylogenetic relationships in this study showed a close affinity between C. zanadreai and C. sinensis. Two new species, C. tetralineata and C. pacifica in Korea also are closely related to monophyletic group clustering the type species of the Acanestrinia subgenus (C. elongata) with all the endemic Italian species (C. bilineata and C. zanandreai). This may suggest that the affinity between the Korean and Danubian-Italian imply genetic convergence or genetic plesiomorphic state between allopatric species that are separated for the Miocene. The mtDNA-based phylogeny for the species of the genus Cobitis from Kores and Europe permits phylogenetic assessment of the morphological transitions of Iamina circularis.

• Asian-Australasian Journal of Animal Sciences
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• 제20권12호
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• pp.1832-1842
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• 2007

Cytochrome P450 aromatase is responsible for the biosynthesis of estrogen. It is also responsible for the endogenous production of 19-nortestosterone (nandrolone), an anabolic androgen unique to pigs. Plasma concentrations of 19-nortestosterone are highest between two and four weeks after birth in male pigs. In the present study, the physiology of 19-nortestosterone was investigated by measuring the mRNA levels of steroidogenic enzymes, estrogen receptors and androgen receptor in the tissues of growing pigs. The expression of aromatase, 17${\alpha}$-hydroxylase and 3${\beta}$-hydroxysteroid dehydrogenase in the testes of male piglets increased between birth and two weeks of age, and then decreased progressively. Similar developmental expressional patterns were observed for 17${\alpha}$-hydroxylase and 3${\beta}$-hydroxysteroid dehydrogenase in the ovaries of female piglets, but without significant aromatase expression. The major form of aromatase expressed in the testes of piglets was identified as type I. Expression of estrogen receptor-${\alpha}$ and -${\beta}$and androgen receptor genes was also detected in both testes and ovaries. A transient elevation of androgen receptor mRNA in male piglets at two weeks of age was also observed in testes. Significant expression of the androgen receptor gene, but not of estrogen receptor-${\alpha}$ and -${\beta}$ genes, was also demonstrated in adipose tissue and muscle. We conclude that the observed increase in the testicular expression of aromatase in male pigs could account for the production of large amounts of 19-nortestosterone at between two and four weeks of age in males. Androgen receptor and 19-nortestosterone appeared to be important for testicular development and might contribute to sexual dimorphism in body composition and muscle development in juvenile pigs.

• 대한치과기공학회지
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• 제42권3호
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• pp.220-227
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• 2020

Purpose: This study aims to investigate the cusp variation pattern of the Korean mandibular second premolar and to determine the difference in tooth diameter and surface area using a virtual three-dimensional model. Methods: Dental casts from 69 students were scanned as a virtual dental models with a three-dimensional dental model scanner. Tooth diameter, absolute and relative individual areas, total crown area, the number of lingual cusps and central groove pattern were analyzed using RapidForm 2004. The Mann-Whitney U-test and the Kruskal-Wallis test were performed to verify sexual dimorphism, the difference in tooth diameter and surface according to the cusp variation pattern (α=0.05). Results: There was no significant difference except in buccolingual diameter (p<0.05) and buccolingual diameter at the cervix (p<0.05). The relative surface area of the total clinical crown was 65.76% for the buccal half and 34.24% for the lingual half, with a ratio of 2:1. In the case of the presence of two lingual cusps, the ratio was 21.47% for the mesiolingual half and 14.12% for the distaolingual half, with a ratio of 3:2. The dominant central groove patterns of the second premolar were the H-pattern (42.0%), followed by the Y-pattern (37.7%), then the U-pattern (20.3%). The relative buccal half was largest in the U-pattern central groove and the relative lingual half was largest in the Y-pattern central groove (p<0.05). Conclusion: This study is significant in that it measured quantitative surface areas and the findings could be a meaningful reference to comprehend dental anatomy in Koreans.

• Animal cells and systems
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• 제14권4호
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• pp.315-322
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• 2010

We studied and compared the age structure, body size, and growth rates of field populations of two Korean salamander species (Hynobius yangi and Hynobius quelpaertensis) to elucidate important aspects of basic population dynamics of these two endemic Hynobius species. In both populations, females were sexually mature at three years of age, while H. yangi and H. quelpaertensis males matured at two and three years of age, respectively. Both males and females of H. yangi and H. quelpaertensis attained a maximum age of 11 years and 10 years, respectively. In both species, the snout-vent length (SVL) and body weight (BW) of the females were greater than those of the males. The SVL, BW, and asymptotic SVL of both male and female H. yangi were smaller than those of H. quelpaertensis. The adult growth rates after sexual maturation of male and female H. yangi were lower than those of H. quelpaertensis, possibly resulting in the smaller body size of the former, although overall growth coefficients were not significantly different between the two species. We also compared the age structure and growth rates of three Korean and three Japanese species of Hynobius.

• 한국동물학회지
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• 제22권4호
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• pp.153-164
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• 1979

A total of 352 specimens of congeneric species of Agkistrodon was collected and morphometric analysis and starch-gel electrophoresis were carried out in order to investigate the taxonomic status of this genus. The results obtained in this study are as follows: Morphometric analysis 1. Three species are recognized based on Gloyd's criteria. There was no specimen that was doubtful to classify correctly. Therefore, it seems that Gloyd's morphological characters are good criteria to identify each species. 2. All three species are sympatric at two localities (Mt. Seolag, Gangwon-do, and Mt. Deogyu, Jeonra-bugdo) and A. caligino년 and A. b. brevicaudus are sympatric at Gwangneung and Mt. Yongmun, Gyonggi-do. No hybrids were found in these sympatric localities. 3. Notable sexual dimorphism was found in meristic characters. 4. A. saxatilis has signicantly more number of ventrals and shorter tail ratio than other two species. 5. There were no significant meristic character differences between A. caligino년 and A. b. brevicaudus. Genetic analysis 1. Among 26 loci investigated, 12 loci (46.1%) were identical in their mobility, 4 loci (15.4%) were nearly identical with minor frequency differences, and 10 loci (38.5%) showed interspecific mobility difference. 2. The average proportion of polymorphic loci was 9.03%. This is considerably less than that of other vertebrates. 3. The average S and D values between species are .695 and .342 respectively. These values indicate that three taxa are distinct species. 4. A. caliginosus is genetically more related to A. saxatilis than to Agkistrodon, namely A. b. brevicaudus, A. caligino년 and A. saxatilis, as proposed by Gloyd. Far from being mere morphological variants, as suggested by Kang and Yoon (1975), they are highly distinctive evolutionary units.

• Imaging Science in Dentistry
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• 제50권4호
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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.

• 대한치과교정학회지
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• 제53권3호
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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.

• 한국환경생태학회지
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• 제28권5호
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• pp.542-549
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• 2014

이 연구는 2006년 5월부터 2009년 6월까지 제주도와 작은 부속섬인 가파도 두 지역에 서식하는 쇠살모사 개체군간 몸의 크기와 성적크기이형 및 이에 따른 환경요인을 밝히고, 종 다양성 유지에 필요한 자료를 제공하기 위하여 이루어졌다. 연구결과, 제주도 개체군의 몸길이는 암컷 242-532mm ($422.0{\pm}46.7mm$, n = 100), 수컷 296-580mm ($434.5{\pm}51.7mm$, n = 63)이었고, 가파도 개체군의 몸길이는 암컷 205-395mm ($335{\pm}43.6mm$, n = 55), 수컷 215-430mm ($328{\pm}39.4mm$, n = 73)으로 암수 모두 제주도 개체군이 가파도 개체군에 비해 큰 것으로 나타났다(암컷 t = 17.343, df = 115, P<0.001; 수컷 t = 19.128, df = 101, P<0.001). 성적크기이형 지수(SSD)는 제주도 개체군이 -0.03으로 수컷이 다소 크고, 가파도 개체군은 0.02로 암컷이 다소 컸다. 이처럼 제주도 개체군과 가파도 개체군이 몸의 크기에 있어 차이가 나타나는 것은 서로 다른 환경에 적응된 결과라 판단된다. 또한 두 지역 개체군 및 새끼의 성적크기이형은 제주도 개체군의 몸길이는 수컷이 암컷보다 다소 컸으나(t = -2.011, df = 117, P<0.05), 가파도 개체군과 새끼에서는 유의한 차이가 없었다. 제주도 개체군에서 머리 길이(F = 6.318, $df_{1,2}$ = 1,117, P<0.05), 머리 폭(F = 8.090, $df_{1,2}$ = 1,117, P<0.01), 눈 사이 거리(F = 15.898, $df_{1,2}$ = 1,117, P<0.001) 및 꼬리 길이(F = 238.488, $df_{1,2}$ = 1,111, P<0.001)에서 수컷이 암컷보다 컸으며, 체중은 암컷이 수컷보다 무거운 것으로 나타났다(F = 64.111, $df_{1,2}$ = 1,114, P<0.001). 가파도 개체군에서는 머리 길이, 머리 폭, 눈 사이 거리에서는 암컷과 수컷 간에 유의한 차이는 없었고, 꼬리 길이에서 수컷이 암컷보다 길었으며(F = 168.555, $df_{1,2}$ = 1,74, P<0.001), 체중은 암컷이 수컷보다 무거운 것으로 나타났다(F = 17.812, $df_{1,2}$ = 1,76, P<0.001). 새끼에서는 머리길이, 머리 폭, 눈 사이 거리에서 유의한 차이가 없었으나, 꼬리 길이(F = 67.793, $df_{1,2}$ = 1,72, P<0.001)와 체중(F = 4.558, $df_{1,2}$ = 1,72, P<0.05)에서 수컷이 암컷보다 크게 나타났다. 새끼에서 성적크기이형 현상이 나타나지 않았던 몸길이, 머리길이, 머리 폭 및 눈 사이 거리가 제주도 개체군에서는 모두 수컷이 암컷보다 큰 것으로 나타나 제주도 개체군에서의 성적크기이형 현상은 성장과정에서 생기는 것이라 판단된다.