• Journal of Korean Society of Forest Science
• /
• v.31 no.1
• /
• pp.48-52
• /
• 1976

In order to investigate the effects of seed weight, size (length and thickness), and maturation period (early maturing seed or late maturing seed) on growth of first-year seedlings in Pinus koraiensis, pot cultivation experiment with seeds collected from Gangweon University Forest was carried out under relatively controlled environment condition. At the end of one growing season, not only fresh weight, length, diameter (at underside of cotyledon) and root length of seedlings, but also number and length of cotyledon were measured. Results are as follows; 1. Germination percentage is independent of weight and size of seeds, but it was influenced by maturation period, that is, late maturing seeds surpass early maturing one in germination percentage. 2. Germination percentage is affected by maturation period of seeds in 18.3% of contribution rate. 3. Each growth of first-year seedlings is influenced considerably by the differences of weight, length and thickness of seeds, that is, heavy and large seeds produce larger seedlings than do light and small seeds. Particularly, fresh weight, diameter, length of cotyledon are significantly affected by differences of seed weight and size (length and thickness) in 50-90% of contribution rate. 4. Differences of seed weight and thickness have a tendency to affect more on growth of first-year seedlings than do differences of seed length. 5. Seedlings from late maturing seeds are superior than those from early maturing one in fresh weight, diameter of seedlings and length of cotyledon, but it's influence is a little.

• Korean Journal of Environmental Biology
• /
• v.27 no.4
• /
• pp.369-374
• /
• 2009

The stumpy bullhead (Pseudobagrus brevicorpus) endemic to Korea is one of critically endangered freshwater fish species. To provide baseline data for its captive breeding and reintroduction we investigated basal characteristics on its growth and sexual maturation in an artificial rearing environment. After 698-day rearing the stumpy bullhead grew up to $89.22{\pm}10.29\;mm$ in total length (TL) and $70.93{\pm}7.68\;g$ in total body weight (BW)($BW=5\times10^{-5}\;TL^{2.678}$; $R^2=0.995$), and showed survival rate of 74.2%. The sex ratio was 1 (471 females) : 1 (473 males), and males ($TL=87.44{\pm}1.07mm$; $BW=8.43{\pm}0.31\;g$) showed significantly faster growth than females ($TL=78.38{\pm}0.92mm$; $BW=6.38{\pm}0.20\;g$) after 663-day rearing. However, condition factor of females was significantly higher than that of males (P<0.05). The number of eggs per female ranged from 508 to 867 (average 734), and their diameters ranged from 0.04 to 1.65 mm. The females which reared about two years in the laboratory condition was able to spawn in the early June after 1~2 days of human chorionic gonadotropin (HCG) injection. The number of hatched fries ranged from 113 to 338 (average 216).

• Korean Journal of Animal Reproduction
• /
• v.23 no.1
• /
• pp.53-61
• /
• 1999

The present study was designed to investigate the effects of gonadotrophins on in vitro growth and maturation in mouse preantral follicles. Ovaries were removed from 12-day-old ICR mice. Follicles were dissociated enzymetically in Leibovitz L-15 medium containing 1 mg/$m\ell$ collagenase and 0.2 mg/$m\ell$ DNase I. The follicles were cultured on Transwell-COL membrane inserts in six well cluster dishes for 10 days. The culture medium was $\alpha$MEM medium supplemented with 5% fetal bovine serum and FSH or HMG. After 10 days of growth in vitro, follicles were allowed to mature for 18~20 hr in medium supplemented with 1.5 IU/$m\ell$ hCG. The oocytes were then denuded of their cumulus cells and assessed maturation status. Concentrations of oestradiol and progesterone were measured with a radioimmunoassay. Oocyte diameter was determined with an ocular micrometer. The survival and Metaphase II rates of oocytes were significantly higher in FSH treatment groups than in control group (P＜0.001), but there were no differences among the groups of treated FSH concentration. The survival and Metaphase II rates of oocytes in HMG treatment group (60.9 and 40.6%) were higher than in FSH treatment group (76.6 and 48.2%) and control group (49.2 and 7.1%). The survival and Metaphase II rates of oocytes on both FSH and LH treatment groups were no differences among the ratios of FSH and LH. Diameter of oocyte was no differences among the treatment groups, but smaller than compared to in vivo grown oocyte. Through the entire culture period, secretions of oestradiol and progesterone were significantly less in control group than in HMG and FSH treatment groups. These results suggest that gonadotrophins playa key role in in vitro culture of mouse preantral follicles. Especially, addition of FSH and LH should be more effective than FSH alone.

• The Journal of the Korean dental association
• /
• v.22 no.12 s.187
• /
• pp.1067-1073
• /
• 1984

In the treatment of functional orthodontic problems, timing is not an issue. All orthodontists start as soon as the condition is recognized. However, there is an active dialogue concerning treatment timing for structure problems. The major points in contention center around the operator's ability is to control the growth of the facial bones and to maintain post-treatment tooth position through the maturation period (especially when this position was gained by techniques involving arch expansion or distal driving of posterior segments). Factors taken into account to determine the best time of orthodontic treatment include diagnosis, interception, growth rate, patient cooperation, eruptive state and treatment period. With those exceptions of all functional problems, mild dental discrepancies and skeletal deficiencies with a predictably excellent growth potential (early treatment), the period immediately following the eruption of the permanent second molars is the period during which most orthodontic treatment should be initiated. At this time the full volume of tooth substances is present, the individual growth pattern in well established, there are sufficient teeth to receive nearly any type of appliances and the patient can easily tolerate the wearing of appliances.

• Fisheries and Aquatic Sciences
• /
• v.26 no.7
• /
• pp.447-454
• /
• 2023

Fast somatic growth is important considerations for successful and competitive aquaculture industry. In rainbow trout reared in South Korea, triploid induction was used to suppress negative influence of reproductive maturation to body growth. However, the effects of triploidy are visible in both mature fish and developing juvenile fish. Thus, it is also important to explicate the effect of triploid induction on growth during the early-life stages of rainbow trout-alevins and fry. Rainbow trout fertilized eggs were subjected to triploid induction and polyploidy was checked by flow cytometry. Diploid and triploid alevins and fry were reared separately in tanks with constant flow of freshwater through flow-through water system and growth measurements were done from zero days after hatching (DAH 0) until DAH 134. The egg-yolk morphometrics of alevins-yolk length, yolk height, yolk volume and yolk weight-were statistically similar (p > 0.05) in both genotypes from DAH 0 to DAH 22. The total length, body height, and body weight of alevins and fry were statistically better (p > 0.05) in both genotypes until DAH 92 but thereafter, triploid had a significantly better growth performance (p < 0.05) over diploid fish until the completion of study at DAH 134. With that, triploid induction did not influence alevin yolk regions and body growth and fry somatic growth until around 3 months after hatching, but considerable growth enhancement was subsequently apparent.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.1
• /
• pp.46-52
• /
• 2009

The purpose of this study was to compare the skeletal maturation of cervical vertebrae according to vertical skeletal patterns in the adolescents. Lateral cephalograms of 198 subjects(10 years old), 216 subjects(12 years old), and 138 subjects(14 years old) were reviewed, and subjects were classified according to vertical skeletal patterns. The 30 subjects were selected with the greatest predominance of vertical growth, and the other 30 subjects, with the greatest predominance of horizontal growth; these subjects comprised the vertical and horizontal groups, respectively. For evaluating of skeletal maturation, the concavity of inferior border and verticohorizontal ratio of cervical vertebrae were observed and measured according to age. The measurements were analyzed statistically by SPSS computerized program. The results were as follows : In general, the concavity of the inferior border of the cervical vertebrae was greater in the horizontal group than the vertical group in all of the 10, 12, 14 year olds, but was not statistically significant. The vertico-horizontal ratio of the 3rd and 4th vertebra of the horizontal groups was a significantly larger than the vertical groups in 12 year olds but did not show any statistical significance in 10 and 14 year olds. There were a weak negative correlations between SUM, FMA and the vertico-horizontal ratio for each groups at 12 ages.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.38 no.3
• /
• pp.237-243
• /
• 2011

The purpose of study is for the certified correlations of hand-wrist radiograph with cervical vertebrae for skeletal maturation in children. Normal evaluation devices of growth stage is sexual feature, biological age, tooth development stage, height and weight. Evaluation of growth potential is very important for childhood and puberty. The skeletal developmental stages were evaluated by using the hand-wrist radiograph and cephalometric radiograph that obtained from 6 to 18 years old children. 1. Chronologic age was not more suitable indicator of skeletal development compared to Skeletal Maturity Indicators(SMI) and Cervical Vertebrae Maturation(CVM) stages. 2. SMI and CVM stages for females occurred earlier than that for male. 3. SMI 1 and 2 stages were corresponded to CVM 1; SMI 3,4 = CVM 2; SMI 5,6 = CVM 3. 4. Reproducibility and reliability of observer for SMI and CVM were excellent. This results suggest CVM stage is comparable to SMI stage in terms of evaluating the skeletal development.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.40 no.1
• /
• pp.21-27
• /
• 2013

In growing children it is frequently found that dental maturation is strongly influenced by the growth rate of maxilla or mandible. If there is evidence to prove this, it might be utilized as a criterion in the early diagnosis of skeletal malocclusion, even before the object's real skeletal features are yet revealed. The purpose of this study was to find out if the difference of dental maturation in over-grown mandible in children with skeletal Class III has any relationship with some skeletal features of mandible. 50 patients in Hellman dental age IIIA with normal occlusion and Class III malocclusion of mandibular over-growth type respectively were selected as study objects. The age estimation was performed on maxillary and mandibular teeth, eruption rate of the 2nd molars of each group have been measured on panoramic radiography, and the differences in dental age of the upper and lower jaw were analyzed under Demirijian's method. The results were as follows: The difference of dental age of maxillary and mandibular teeth between the two groups was 0.66 and 1.20 years respectively, with a higher difference in the experimental group (p < 0.05). The difference of eruption rate of the maxillary and mandibular second molar was not found between two group (p >0.05).

• The Korean Journal of Malacology
• /
• v.20 no.1
• /
• pp.75-84
• /
• 2004

Reproductive cycle, the condition index, sex ratio of the Pacific oysters, Crassostrea gigas were investigated by histological and morphometric data. The specimens were collected in the two oyster farms of Geoje and Namhae, Gyeongsangnam-do, Korea, from November 1995 to October 1996. Growth of shell length in two regions was similar, but growth of total weight of the oyster in Namhae was faster than that in Geoje oyster farm. The spawning periods in female and male clams were from July to October in Geoje and from June to October in Namhae oyster farm. Ripe oocytes were approximately 50 m in diameter. The reproductive cycle of in females and males in Geoje and Namhae oyster farms can be divided into five successive stages: early developing, late developing, ripe, partially spawned and spent/inactive. Monthly changes in gonad developmental phases showed somewhat different patterns between female and male clams except for the spawning period. On the whole, however, monthly changes in the gonad developmental phases showed a similar pattern in the same sex. The sex ratios of females to males in Geoje and Namhae oyster farms were not significantly different from a 1:1 sex ratio ($x^2$ = 0.55 (p > 0.05) in Geoje and $x^2$ = 0.27 ( p > 0.05) in Namhae). Artificial induction of maturation by heating of adult oysters (two-year-old) was investigated from 17 January to 18 March in 1996. Maturity at the fixed water temperature group of $20^{\circ}C$ was 80%, it showed the highest maturity of experimental groups cultured for five weeks. The survival (%) of Crassostrea gigas in the raised water temperature experimental groups (15, 20, $25^{\circ}C$) were over 98.5%, as similar to the control group (100%). But, the survival of C. gigas in the fixed water temperature experimental groups (15, 20, 25, $30^{\circ}C$) were decreased with the increase of the water temperatures. In the fixed water temperature experimental group of $30^{\circ}C$, the survival was 51.1%. Base on these results, the fixed water temperature of $20^{\circ}C$ was the best condition for artificial induction of sexual maturation.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.48 no.3
• /
• pp.255-268
• /
• 2021

The aim of this study was to investigate the relationships between the stages of calcification of various teeth and skeletal maturity stages among Korean subjects. The samples were derived from hand-wrist, panoramic radiographs, and lateral cephalograms of 743 subjects (359 males and 384 females) with ages ranging from 6 to 14 years. Calcification of seven permanent mandibular teeth on the left side were rated according to the system of Demirjian. To evaluate the stage of skeletal maturation, hand-wrist radiographs were analyzed by skeletal maturity indicators (SMI) system of Fishman and lateral cephalograms by cervical vertebral maturation (CVM) method of Baccetti. Statistically significant relationships were found between dental calcification and skeletal maturity stages according to Spearman rank-order correlation coefficients (r = 0.40-0.84, p < 0.001). The second molar showed the highest correlation and central incisor showed the lowest correlation for female and male subjects. For both sexes, canine stage G and second molar stage F were related to SMI 6 and CS 3. Because of the high correlation coefficients, this study suggests that tooth calcification stages from panoramic radiographs might be clinically useful as a maturity indicator of the pubertal growth period in Korean patients.