• Imaging Science in Dentistry
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• 제50권3호
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• pp.209-216
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• 2020

Purpose: In India, the age of 14 years is the legal age threshold for child labour. Therefore, in suspected instances of child labour, age assessment plays a crucial role in determining whether a violation of the law on the employment of children has occurred. The aim of this retrospective cross-sectional study was to assess the discriminatory ability of stages of cervical vertebral maturation (CVM) in predicting the legal age threshold of 14 years. Materials and Methods: Routinely taken lateral cephalograms from 408 subjects aged 10 to 18 years were evaluated retrospectively using the CVM stages described by Baccetti et al. Descriptive statistics, accuracy, sensitivity, specificity, positive and negative predictive values, and likelihood ratios were calculated for stages 2, 3, and 4 of CVM. Results: Real age increased as the CVM stage gradually increased. The results of 2×2 contingency tables showed that CVM stage 4 produced an accuracy of 71% and 73%, a false positive rate of 7% and 18%, and a post-test probability of 59% and 68% for boys and girls, respectively. Conclusion: Based on these findings, it can be concluded that the stages of CVM are of limited use for predicting the attainment of the legal age threshold of 14 years. Future studies should investigate whether combinations of skeletal and dental methods could achieve better accuracy and post-test probability.

• 한국가축번식학회지
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• 제8권2호
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• pp.70-78
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• 1984

In order to investigate the spermiogenesis of Korean cattle spermatozoa, the tissue obtained from the testis and the epididymis of six matured bull were conventionary prepared as thin sections and these sections were observed under a transmission electron microscope. Based on the development of the various permanent organelles and certain transient structures, the spermiogenesis of the Korean cattle could be divided into four main phases: Golgi, cap, acrosome and maturation, and these phases had been further subdivided into a total of nine stages. In the maturation phase, the condensation of the nuclear karyoplasm had progressed from the u, pp.r side to the lower side of the nucleus as the movement of the nuclear ring which would be disa, pp.ared after maturation.

• 한국가축번식학회지
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• 제9권1호
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• pp.46-55
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• 1985

In order to investigate the spermiogenesis of the Korean goat, the tissue obtained from the testis and the epididymis of eight matured bucks were conventionary prepared as thin sections and these sections were observed under a transmission electron microscope. Based on the development of the varous permanent organelles and certain transient structures, the spermiogenesis of the Korean goat could be divided into four main phases: Golgi, cap, acrosome and maturation; and these phases had been further subdivided into a total of nine stages. There was abundance of the contents of acrosomal vesicle contained ring-shaped material surrounding the acrosome in the early cap stage. The mitochondria made the mitochondrial sheath started from the annulus towarding the neck and formed helical arrangement in the mid maturation stage, The postacrosomal denselamina was a, pp.ared to be wave-shape in the late maturation stage. The spermiogenesis of the Korean goat was found to be basically similar to that of the Korean cattle.

• 대한의생명과학회지
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• 제11권4호
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• pp.545-553
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• 2005

The present study provides descriptions of the cellular associations of the seminiferous epithelium cycle in the Crocidura shantungensis. The cycle of the seminiferous epithelium was divided into 14 stages, and developing spermatids were subdivided into 15 steps. The Golgi phase occurs the first two steps, and the cap phase had the next four consecutive steps. The acrosomal and maturation phases were consisted of steps $7\~14$, and the remaining one step consisted the spermiation phase. The Ad type of spermatogonia was observed whole stages, and Ap, In and B spermatogonia were observed from stage II to stage VI. The preleptotene, leptotene and zygotene of primary spermatocytes were observed from VII to XIV stages, and pachytene spermatocyte was observed from I to XII stages. The diplotene spermatocyte was observed XIII stages, and meiotic figures and secondary spermatocytes were observed stage XIV. Our results provide the foundation for a variety of future studies of the spermiogenesis of C. shantungensis.

• 한국가축번식학회지
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• 제13권2호
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• pp.70-78
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• 1989

Mouse eggs recovered from oviducts at one hourly intervals between 10 and 20 hours after administration of hCG were fixed, stained and then investigated the rate of in vitro fertilization and nuclear maturation. In case of out- bred ICR mice, ovulations were occured between 11 and 13 hours after hCG injection. The stages of in vitro maturation of eggs recovered from female mice at various times after hCG injection were metaphase I, anaphase I, telophase I and metaphase II. However the majority was metaphase I(17.6 to 44.4%) and metaphase II(42.9 to 80.0%) stage. When the eggs were inseminated with epididymal spermatozoa, the fertilization rate was declined as the egg recovery time after hCG administration was delayed. That is, the proportion of eggs undergoing fertilization became higher(68.1 to 77.4%) in the eggs at 12 to 15hr after injection of hCG than those(17.5 to 56.4) at 16 to 20 hr after injection of hCG. Also, when nuclear maturation of the unfertilized eggs were observed at 8 hours after insemination, the majority was in metaphase I and metaphase II and no anaphase I and telophase I were observed.

• 한국양식학회지
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• 제16권4호
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• pp.245-251
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• 2003

2000년 1월부터 12월까지 남해안 한산만 해역에서 채집한 홍합의 생식소 발달과 생식주기에 관하여 조직학적 방법을 이용하여 조사하였다. 홍합은 자웅이체이며, 생식소는 암 수 모두 다수의 배우자형성소낭으로 이루어져 있었다. 생식소지수(GI)는 2월(3.40)에 가장 높았으며, 8월(1.18)에 가장 낮았다. 비만도(CI)는 생식소지수(GI)와 유사하게 변화하였다. 홍합의 주 산란기는 2∼3월이며, 생식주기는 휴지기(8∼11월), 분열증식기(11∼12월), 성장기(12∼1월), 성숙기(1∼2월), 부분방출기(2∼4월), 완전방출 및 퇴화흡수기(4∼7월)로 구분할 수 있었다. 성비(암:수)는 1:0.96으로 조사되었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제34권2호
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• pp.23-31
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• 2017

Bumblebees, more efficient than honeybees, provide important services for pollination especially in tomato, pepper, cucumber, strawberries and other crops grown under tunnel farming or glasshouse conditions to yield maximization. These bees require pollen and nectar to meet their dietary needs and maintain their colony structure, development and reproduction. Keeping in view their economic importance, the effect of five concentrations of sugar and honey solutions (1:1, 1:1.5, 1:2, 2:1,1.5:1) each as alternative to nectar were used to observe their effect on life history parameters of Bombus terrestris. The 1:1 ratio of sugar solution was found most effective followed by 1.5:1, 1:1.5, 1:2 and 2:1 and also more effective of all five concentrations of honey solutions on all three stages of colony development i.e., at colony initiation, colony development and colony maturation stages. At colony initiation stage, early pre-oviposition period ($6.40{\pm}0.97$ days), early emergence of first worker in the first batch ($25.40{\pm}1.21$ days) and maximum numbers of workers ($6.20{\pm}0.24$) emergence in the first batch were observed at 1:1 ratio of sugar solution. Colonies reared on 1:1 ratio of sugar solution reached earlier ($52.13{\pm}1.28$ days) at colony foundation stage with minimum mortality ($3.27{\pm}0.54$ workers). At colony maturation stage, maximum numbers of workers, sexual (males, queens) and maximum mother queen longevity was observed at the same 1:1 ratio of sugar solution. It can be suggested from present study that sugar solution as alternative of nectar at 1:1 ratio was better than other sugar concentration levels and also from those of honey solution.

• 대한치과교정학회지
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• 제52권5호
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• pp.345-353
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• 2022

Objective: To investigate airway volumes using cone-beam computed tomography (CBCT) by skeletal patterns, sex, and cervical vertebral maturation (CVM) stages in Korean adolescents. Methods: The sample consisted of pretreatment CBCT and cephalograms of 95 adolescents (aged 12-19) obtained out of 1,611 patients examined for orthodontic treatment from 2018 to 2020 in Kyungpook National University Dental Hospital. The samples were classified into two sex groups; three skeletal pattern groups, four chronological age groups and four CVM stages. Nasopharyngeal volumes (NPV), oropharyngeal volumes (OPV), total pharyngeal airway volume (TAV) and minimum cross-sectional area (MCA) measurements were taken from the CBCT. Multiple linear regression analyses to find out which one of the independent variables are good predictors for airway variables. Significant factors were analyzed by two-way multivariate analysis of variance (MANOVA) then multiple comparisons were analyzed using a t-test, and Fisher least significant difference. Results: Age, sex, CVM, and Sella-Nasion-B point have significant influence on airway variable. Males and females showed similar patterns of change in chronological age groups 1-3; however, males had larger NPV, OPV, and MCA at CVM in group 4. According to CVM stages, males had larger OPV, TAV, and MCA at CVM stage 6 (p-value: 0.019, 0.021, 0.015, respectively) and no sex differences at CVM stages 3, 4, and 5. Conclusions: Skeletal patterns have an effect on airway volume. Sex differences were found in CVM 6.

• 대한치과교정학회지
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• 제48권1호
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• pp.39-47
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• 2018

Objective: The aim of this study was to establish the normative data of dentofacial transverse dimensions according to the skeletal maturation stage in Korean adolescents with good occlusion, assess gender differences and determine correlations between transverse variables. Methods: A total of 577 Korean subjects between ages 7 to 19 years and exhibiting skeletal Class I occlusion were categorized by skeletal maturation index (SMI) of Fishman using hand-wrist radiographs. Dentofacial transverse dimensions were assessed using posteroanterior cephalograms. Independent two-sample t-tests were used to analyze differences between genders. Pearson correlation coefficient was used to determine the correlation between transverse measurements. Results: Dentofacial transverse norms relevant to skeletal maturation stages were established. The average maxillomandibular width difference and ratio at growth completion was 22.16 mm and 77.01% for males; 23.70 mm and 74.06% for females, respectively. Males had greater facial, maxillary and mandibular widths compared to females at every SMI stage. The maxillary and mandibular intermolar widths showed the strongest correlation for both sexes (r = 0.826 for males, r = 0.725 for females). Conclusions: Dentofacial transverse norms of Korean adolescents were established according to developmental stage. All dentofacial widths were greater in males at growth completion. Maxillary and mandibular intermolar widths were strongly correlated. This study may serve as a guideline for the assessment of dentofacial transverse growth according to skeletal maturation stage in Korean adolescents with good occlusion.

• Parasites, Hosts and Diseases
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• 제30권4호
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• pp.355-358
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• 1992

Oxygen radical은 생물체의 산소대사 과정의 부산물로 생성되어 세포내 여러 성분을 불환성화시키거나 미생물에 대한 방어기전으로 작용한다. 기생충에 존재하는 antioxidant enzyme은 숙주의 방어기전에서 유리하는 oxygen radical의 독성을 제거하므로 이 효소의 활성도는 기생충의 생존에 영향을 미친다고 생각하고 있다. 폐흡충은 피낭유충이 종숙주에 침입한 다음 숙주내 조직이행 시기를 거쳐서 폐에 도달하여 성충이 되므로 이 과정에서 각 시기별 산소독성과 이에 대항하는 효소의 환성이 다를 것으로 추정하였다. 폐흡충의 피낭유충과 감염후 4주, 8주, 12주에 얻은 충체의 추출물을 조효소(조효소)로 하여 SOD, catalase, peroxidase, glutathione peroxidase의 활성도를 측정하였다. 각 효소의 비환성도(specific activity) 중 catalase는 피낭유충에서 최고치였으며, SOD 와 peroxidase는 4주 충체에서 가장 높았고, glutathione peroxidase는 8주 충체에서 높았다. 이들 4가지 antioxidant효소의 비환성도는 감염 12주인 성충에서 모두 낮게 측정되어 조직 이행시기의 충체에서 더 높은 효 소 활성도를 지니고 있음을 알 수 있었다.