• Radiation Oncology Journal
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• v.6 no.1
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• pp.1-11
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• 1988

Recovery from potentially lethal damage (PLDR) after irradiation was studied in plateau-phase culture of Vero cells in vitro. Unfed plateau-phase cells were irradiated with dose of 1 to 9Gy using Cs-137 irradiator. Cells then were incubated again and left in situ for 0, 1, 2, 3, 4, 5, 6, and 24 hours and then were trypsinized explanted, and subcultured in fresh RPMI-1640 media containing $0.33\%$ agar. Cell survival was measured by colony forming ability. An adequate number of heavily irradiated Vero cells were added as feeder cells to make the total cell number constant in every culture dish. As the postirradiation in situ incubation time increased, surviving fraction increased by PLDR. The rate of PLDR was so rapid that increased surviving fraction reached saturation level at 2 to 4 hours after in situ incubation. As the radiation dose increased, the rate of PLDR fastened and the magnitude of increased surviving fraction at saturation level by PLOR also increased. In analysis of cell survival curve fitted to the linear-quadratic model, the linear inactivation coefficient $(\alpha)$ decreased largely and reached nearly to zero but the quadratic inactivation coefficient $(\beta)$ increased minimally by increment of postirradiation in situ incubation time. So PLDR mainly affected the damage expressed as $\alpha$, In the multitarget model, significant change was not obtained in $D_0\;but\;in D_q$. Therefore, shoulder region in cell survival curve was mainly affected by PLDR and terminal slope was not influenced at all. And dose-modifying factor by PLDR was relatively higher in shoulder region, that is, in low dose area below 3 Gy.

• Korean Journal of Veterinary Service
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• v.21 no.3
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• pp.285-300
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• 1998

1. The number of average milking cows, clinical forms of mastitis, mastitis-developing cows, and cows killed by mastitis a year were 25.7, 1.8(7%), 6.3(26%), and 2.7(10.1%)heads, respectively. The annual grade changes of standard plate counts(SPC) and somatic cell counts(SCC) showed the grade 1A of SPC diminished sharply from April to August, we think it was due to the lack of proper management in farming season and the grade 3 of SCC indirectly influenced increased in huge during August. 2. The average number of parturitions of farms was 2.3, but 50% of below 1 parturition were 22 farms(31%), 50% of above 3 parturitions were 16(23%) out of 71 farms. According to grades of the number of parturitions of milking cows per each farm, the farms' grades recording 3 parturitions and 50% were little bit excellent. 3. The actual situation research of foremilking CMT revealed 35 out of 74 farmer didn't do CMT Among them(35 out of 74 farmers), 80% did not test thanks to the troublesome process of the CMT. SCC grade 3, among farms who did foremilking CMT once or twice a month and who did not were 29% and 40% respectively and SPC grade 1A were 55% and 9%, respectively. 4. The research of actual situation on milking management let us know 29 farms(39%) did not do lastmilking, 37 farms(49%) usually did overmilking, and 34 farms(46%) did milking for 4 or 5 minutes. Grades according to average requiring times of milking showed SCC grade 1 of farms milking within 7 minutes was 11% and SPC grade 1A was 34%, on the other side, farms milking more than 7 minutes were 0% in SCC grade 1 and 13% in SPC grade 1A. Grades according to the starting time of milking after rubbing teats showed SPC grade 1A of farms starting milking at about 1 minute and over 2 minutes were 50% and 20%, respectively. 5. The research of actual situation on hygienic milking management uncovered 65 farms(88%) were using one towel which was used in washing teats and udders to wash more than 3 to 4 cows, and 53 farms(72%) were using one dried towel to dry udders not for each cow but for more than 3 to 4 cows after washing. Also, on milking turns disclosed 30 farms(40%) were milking cows in the order of incoming without isolation of a dominant group. According to grades of towels used in washing teats and udders, farms using a towel for each cow were 56% and a towel for over 3 cows were 31% in SPC grade 1A. According to using-or-not grades of dried towels after washing udders, farms using a towel for each cow were 79% and a towel for over 3 cows were 21% in SPC grade 1A. 6. Farms doing teat-dipping before milking were 7(10%), not doing teat-dipping after milking, or doing sometimes were 9(12%), and doing right after milking were 57(77%). And farms doing teat-dipping after dry cows and before delivery were 21(28a ). Farms using bethadine as an antiseptic solution were 70(95%), 40 farms(59%) diluted it with water as weak as 5 to 10 times, and on drying cows 64 farms(87%) slowly did it more than 2 days. Grade 1A of SPC of farms doing teat-dipping at every milking was 38%, farms doing occasionally or not was 33%, and farms doing it right after milking was 37% and doing after milking more than 5 cows was 20%. Grade 1A of SPC among farms diluting bethadine 5 times and diluting 5 to 10 times with water were 36% and 33%, respectively, and Grade 3 of SCC were 35% and 32%, respectively. 7. Studies on nonlactating period medical treatment, as the cows were on dry, 54 farms treated with their own hands.73 farms(98%) had bovine mastitis treated for themselves. And on applying medicines against mastitis, 55 farmers chose them on the basis of their own experience, 42 farms(57%) were treated more than 3 days. 41 farms(55%) dumped away the mastitis infected milk separately, 24 farms(32%) were feeding and milking at the same time. 8. Fifty-six farms(76%) always washed and disinfected milking machines after milking. Farms using the milking machines at low, or variable vacuum pressures, or at the vacuum pressure, set at the moment of its installation were 31(42%), and farms that did not know pulsation ratio were 27(37%). Farms changing liners when they were torn 8(11%), 58 farms(78%) said they checked milking system when there were wrong with them, 31 farms(42%) changed milking hoses when they found out problems, and 42 farms(57%) cleaned vacuum and milking systems when they felt dirty. The SPC grade 1A of farms washing and sterilizing milking machines was 38% and farms only washing was 28%.

• Korean Journal of Ichthyology
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• v.19 no.2
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• pp.107-111
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• 2007

Sex differentiation of the brown croaker Miichthys miiuy (Basilewsky) is described from hatching to the 120th day post-hatching (dph) (water temperature $24^{\circ}C$). Primordial germ cells (PGCs) were observed on the 20th dph (10.4 mm total length (TL), 0.14 g body weight (BW), and began to protrude into the peritoneal cavity from the 40th dph (19.4 mm TL, 0.39 g BW). On the 65th dph (31.3 mm TL, 0.93 g BW, $1,560D^{\circ}$ (degree-days)), initial ovarian differentiation was identified by the PGCs with condensed chromatin, and their transformation into meiotic oocytes. By the 120th dph (4.60 mm TL, 1.38 g BW, $2,880D^{\circ}$), the oocytes were in the perinucleolus stage and had increased from 20 to $40{\mu}m$ in diameter. While ovaries gradually grew after sex was differentiated, testes continued to multiply from the 65th dph. On the 80th dph (37.9 mm TL, 1.39 g BW, $1,920D^{\circ}$), the beginning of testis lobule formation was indicated by the occurrence of spermatogonial cysts enveloped by somatic cells in some of the testes. On the 120th dph, the testis lobules of some of the fish contained all germ cell stages through to the spermatocytes. Therefore, the sex differentiation type of the brown croaker is identified as gonochoristic.

• Journal of Mushroom
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• v.2 no.3
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• pp.115-126
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• 2004

Somatic hybrids of inter-compatible and inter-incompatible strains were obtained by protoplast fusion. The fusion products between compatible strains, Pleurotus ostreatus and P. florida, formed heterokaryons, while fusants between incompatible strains such as P. cornucopiae + P. florida, P. ostreatus + Ganoderma applanatum, P. florida + Ganoderma lucidum, and P. ostreatus + Flammulina velutipes formed synkaryons that retained genes from both parents. The heterokaryons showed the same level of basidioma development. In contrast, the synkaryons showed unique characteristics including clamp connection formation at mitosis, either partner basidioma development, and abnormal segregation and recombination compared with inter-compatible strains. Synkaryons can be classified into homokaryoyic and heterokaryotic type. A comparison of somatic hybrids with compatible and incompatible strains was made using random amplified polymorphic DNA (RAPD) analysis. The heterokaryons between compatible species showed the same level of variability and contained both parental RAPD bands. In contrast, most of the synkaryons between incompatible species showed similarity to those of either parental bands and non-parental RAPD bands. Synkaryons can be classified into microgenome insertion type and macrogenome insertion type. A tetrapolar mating system was found among monospore isolates in somatic hybrids and wild type P. ostreatus. Homokaryons from each somatic hybrid combination were paired with tester homokaryons of the initial wild type of P. ostreatus. The changed mating types were identified in progenies. The pattern of mating type switching in somatic hybrids depends on compatibility of fusion partner. There are several factors related to the mechanism of clamp connection formation and fruiting body development of synkaryons. Of these,the major factor may be associated with self-fertility and mating type switching such as homokaryotic fruiting of wild type P. ostreatus. This review will discuss these aspects.

• Journal of Korean Society of Forest Science
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• v.17 no.1
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• pp.1-15
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• 1973

In an effort to improve the major tree species in Korea, the seed of Robinia pseudoacacia, Pinus rigida, Pinus densiflora, Pinus thunbergii and Larix leptolepis were treated with X-ray and thermal neutron at the Brookhaven National Laboratory, and germination rate of the seed and some characteristics of the seedlings from irradiated seed were investigated and the results were summarized as follows. 1. The germination rate of the irradiated seed of Robinia pseudoacacia, Pinus densiflora, Pinus thunbergii and Pinus rigida was decreased, when the irradiation time of thermal neutron increased from 3 hours to 9 hours. The seed of Larix leptolepis was completely died out in all range of irradiation time. 2. The seed of Pinus densiflora, Robinia pseudoacacia and Pinus rigida showed low germination rate, when the dosage of radiation increased in the range of 10,000r-30,000r X-ray. This dosage of radiation was almost lethal to the seed of Pinus thunbergii and Larix leptolepis. 3. The growth rate of radiated Robinia pseudoacacia has been decreased when the dosage of X-ray and thermal neutron increased. However, the trees treated with thermal neutron for 3 hours showed 14.9 percent-increase in seedling height and some thornless individuals appeared in this treatment. 4. Individuals with variegated leaf, rugose leaf and albino were appeared in X-ray and thermal neutron treatment. 5. Abnormal mitosis of somatic cell, cell with two nucleoli, cell with two nuclei and chromosome clump in mitosis of somatic cell were observed in Robinia pseudoacacia irradiated with thermal neutron. 6. Resistanty against pawdery mildew was decreased in Robinia pseudoacacia radiated with X-ray and thermal neutron. 7. Length of stomata did not show any difference however number of stomata per unit area decreased in Robinia pseudoacacia radiated with thermal neutron. The leaves of Robinia pseudoacacia radiated with thermal neutron were thicker than those of non-treated one, but width of palisade tissue was decreased. The most sensitive one among those species to the thermal neutron treatment was Larix leptolepis, followed by Pinus densiflora, Robinia pseudoacacia, Pinus thunbergii and Pinus rigida in the order. In X-ray treatment, the most sensitive one was Larix leptolepis, followed by Pinus densiflora, Pinus thunbergii, Pinus rigida and Robinia pseudoacacia in the order. Morphological, cytological variation of the radiated Robinia pseudoacacia seemed to indicate some possibility to be used for tree improvement.

• Journal of Korean Society of Forest Science
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• v.62 no.1
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• pp.60-67
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• 1983

Karyotype analysis of somatic chromosome was attempted to find out the relationship among the 3 species of Abies growing in Korea, and A firma introduced from Japan The results were summarized as follows: 1) The number of somatic chromosome was equal for all species, 2n=24. 2) When somatic chromosome was arranged by descending order of the short arm length, the long arm of number 9 chromosome of A. holophylla was much larger than that of the other species. A. koreana and A. nephrolepis had a similarity in b/a value and A. holophylla and A. firma were also similar. 3) When it was arranged by descending order of the short arm length, eight chromosomes of A. koreana and A. nephrolepis showed a similar in b/a value, and two chromosomes of A. holophylla and A. firma did in its value. 4) When it was arranged by descending order of total length, chromosome numbers 7 and 8 in A. koreana were particularly similar to those in A. nephrolepis. 5) When it was arranged by descending order of total length, six somatic chromosomes of A. koreana and A. nephrolepis were similar in b/a value, and two somatic chromosomes of A. holophylla and A. firma similar in its value. 6) When it was arranged by descending order of long arm length, in the of b/a value of chromosome number one in A. koreana and A. nephrolepis was much larger, and that in A. holophylla and A. firma was much smaller than that in the others.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.35-43
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• 1996

The appearance of the primordial germ cells (PGC's), early gonadogenesis, sex differentiation and sex ratio of the embryo in the viviparous teleost, Ditrema temmincki were investigated by using photomicroscopy. The PGC's were first observed in the fibrous mesenchymal tissue located between the early alimentary tract and the dorsal body wall in the late embryonic development stage. During the period from the hatching to the individual total length (TL) of 4.0 mm the PGC's were evenly distributed in the fibrous mesenchymal tissue between alimentary tract and body wall. But the period of TL 5.0 mm mesenchymal tissue separated from the dorsal body wall, the PGC's moved to the posterior mesenchymal tissue and formed the primitive gonad. During the early gonadogenesis, differentiation of the testis and ovary were distinguished from the arrangement of the germ cells and somatic cells. Gonad of embryo in TL 10.0 mm can be separated into the ovary and testis by external morphology. The testis had a separated form which was consisted with two lobes, and the ovary had a fused form in half-posterior part. In the testicular differentiation of the embryo, histological pattern of the seminiferous tubule appeared when TL of the embryo was to be 25.0 mm, for the seminal vesicle was formed In the individual TL of 30.0mm. The testis of the embryo with TL of 45.0 mm was similar to that of the adult fish in the external and internal structures. In the ovarian differentiation, formation of the ovigerous folds and the ovarian cavity were clearly observed when the TL reached to 30.0 mm. The ovary from the individual with TL of 60.0 mm was differentiated into a similar ovary as seen in the adult fish in the external and internal structure. Right before parturition the total length of the individual was approximately 63.0 mm of which the individual embryo has an ovary containing the oocytes in the chromatin nucleolus stage, or a testis containing the spermatogonia, respectively. And the embryonic sex ratio of female to male was 1.65 : 1. Ditrema temmincki is dioecism and the pattern of sex differentiation is belonged to a differentiation type.

• Reproductive and Developmental Biology
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• v.32 no.1
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• pp.51-58
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• 2008

This study was performed to investigate the relation between birth weight and survivability on the production of cloned Hanwoo calves. The 580 cloned embryos were transferred into the 293 recipients. The pregnancy rate of the cloned embryos was 72.3% at 50 days after embryo transfer, and then the rate was dramatically decreased. The mean gestation lengths were 287 days in both clone (range of$279{\sim}295$ days) and artificial insemination (AI, range of $255{\sim}293$ days) calves, respectively. The mean birth weight of cloned calves (30.3kg) was significantly higher compared to that of AI calves (23.7kg) (p<0.05). Among the cloned calves, the birth weight was not different in both normal delivery (n=17, 29.9kg) and caesarean section (n=14, 32.3kg). The weight, however, was significantly higher in the clones (n=18, 32.8kg) dead within 175 days than that of the clones (n=11, 28.3kg) alive more than 175 days after birth (p<0.05). Interestingly, all cloned calves weighed <15kg (n=5) or >35kg (n=9) at birth have been dead within 175 days from the date of birth. The causes of death in the cloned calves were premature birth (n=2, 10.0%), abnormal function of lung and liver (n=2, 10.0%), abnormal function of lung (n=4, 20.0%), malformation (n=4, 20.0%), unknown (n=4, 20.0%), and sudden death syndrome (n=4, 20.0%), respectively. Our findings suggest that normal birth weight is one of the most important factors to survive more than 6 months in cloned calves.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.359-366
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• 2016

Tradescantia is a perennial plant in the family of Commelinaceae. It is known to be sensitive to radiation. In this study, Tradescantia BNL 4430 was irradiated with gamma radiation at doses of 50 to 1,000 mGy in a phytotron equipped with a $^{60}Co$ radiation source at Korea Atomic Energy Research Institute, Korea. At 13 days after irradiation, we extracted RNA from irradiated floral tissues for RNA-seq. Transcriptome assembly produced a total of 77, 326 unique transcripts. In plantlets exposed to 50, 250, 500, and 1000 mGy, the numbers of up-regulated genes with more than 2-fold of expression compared that in the control were 116, 222, 246, and 308, respectively. Most of the up-regulated genes induced by 50 mGy were heat shock proteins (HSPs) such as HSP 70, indicating that protein misfolding, aggregation, and translocation might have occurred during radiation stress. Similarly, highly up-regulated transcripts of the IQ-domain 6 were induced by 250 mGy, KAR-UP oxidoreductase 1 was induced by 500 mGy, and zinc transporter 1 precursor was induced by 1000 mGy. Reverse transcriptase (RT) PCR and quantitative real time PCR (qRT-PCR) further validated the increased mRNA expression levels of selected genes, consistent with DEG analysis results. However, 2.3 to 97- fold higher expression activities were induced by different doses of radiation based on qRT-PCR results. Results on the transcriptome of Tradescantia in response to radiation might provide unique identifiers to develop in situ monitoring kit for measuring radiation exposure around radiation facilities.

• Korean Journal of Poultry Science
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• v.31 no.1
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• pp.9-15
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• 2004

This study was conducted to evaluate the effects of dietary herbal plant mixture on the performance in laying hens under heat stress. One hundred ninety two 54-weeks-old ISA Brown commercial layers, were used in 56 d experimental assay. Dietary treatments included CON (control; basal diet), HPM0.05 (basal diet ＋ 0.05% herbal plant mixture), HPM0.1 (basal diet ＋ 0.1% herbal plant mixture), and HPM0.2 (basal diet ＋ 0.2% herbal plant mixture). For overall period, the hens fed with HPM0.1 and HPM0.2 diets showed lower in the hen day egg production than the hens fed with CON diet(P＜0.05). At the end of the experimental period, egg weight was heavier in HPM 0.1 treatment than in CON (P＜0.05). There were no significant differences among the treatments in egg shell breaking strength, egg shell thickness, Haugh unit, and yolk color unit. Total cholesterol concentration of yolk tended to decrease as the level of herbal plant mixture in the diet increased. Total protein of blood was higher in the hens fed with herbal plant mixture than in the hens fed with CON diet (P＜0.05). Albumin concentration of blood was increased in HPM0.05 and HPM0.1 treatments compared with CON(P＜0.05). Red blood cell (RBC) and white blood cell (WBC) concentrations in serum were increased in HPM0.1 and HPM0.2 treatments compared with CON treatment (P＜0.05). In conclusion, dietary herbal plant mixture in laying hens under heat stress adversely affected egg production but increased total protein, albumin, RBC and WBC in blood.