• Development and Reproduction
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• v.16 no.2
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• pp.107-112
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• 2012

Early growth, the rate of yolk sac absorption, and nucleus size in liver parenchymal cells were correlated with the nutritional status of first feeding larval haddock, Melanogrammus aeglefinus. Larvae that successfully began exogenous feeding maintained high growth rates, delayed yolk sac resorption, and had larger hepatocyte nuclear sizes than starved larvae. At 10 days post hatch (DPH) the cumulative mortality in the starved larval haddock group was 100%. The area of the hepatocyte nuclei in starved larvae gradually decreased, reaching its lowest value by 9 DPH. Our results support the current practice of providing the first food supply at 3 DPH. Hepatocyte nuclear size can be used to assess larval haddock nutrition status, and may be a good criterion for assessing the success of transition from endogenous to exogenous feeding.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.43-44
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• 1998

Effect of somatic cell coculture on hatching of mouse blastocyst was examined. Mid-blastocysts were cocultured with granulosa cell primary culture or Sertoli cell line ($TM_{4}$) derived from mouse testis for 48 hr. Blastocysts cultured in medium (10% FBS) started to hatch more faster than cocultured embryos during 12 hr of coculture. After then blastocysts cocultured with somatic cell hatched faster than control. Degeneration of embryos was also greately reduced by coculture. This result suggested the potentiation of hatching as well as embryonic viability by coculture with somatic cell and Sertoli cell line can be used for embryo coculture.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.5
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• pp.41-48
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• 1987

The aerodynamic critical phenomenon of notch-back type automobile-like bodies was investigated experimentally. The aerodynamic forces were measured for the various bodies of different back-light rake angle at R$_{e}$0.8*10$^{5}$ , 1.0*10$^{6}$ and 1.4*10$^{6}$ . Also, surface flow visualization was effected by the oil mixture. It was found that the critical phenomenon for the notch-back type bodies was milder than for the hatch-back type bodies; the drag vs. slant angle curve for the notch-back type bodies exhibiting local maximum was much smoother. Surface oil flow visualization revealed that the flow pattern associated with the critical phenomenon was characterized by the reattachment of the separated flow on the boot. The effect of the forebody on the critical phenomenon was seen to be negligible.e.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1179-1184
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• 2008

Commercial nanometer sized silver is widely used for its antibacterial effect; however, nanoparticles may also have ecotoxicological effects after being discharged into water. Nanometer sized silver can flow into aquatic environments, where it can exert a variety of physiologically effects in living organisms, including fish. The present study aimed to investigate the effect of nanometer sized silver on the development of zebrafish embryos, analyze the properties of commercial nanometer sized silver and define the toxicity relationship between embryogenesis and hatched flies. The commercial nanometer sized silver was analyzed in the $Ag^+$ ion form. The hatch rate decreased in the nano-silver exposed groups (10 and 20 ppt); furthermore, the hatched flies had an abnormal notochord, weak heart beat, damaged eyes and curved tail. The expression of the Sel N1 gene decreased in the nano-silver exposed groups, and the catalase activities of the exposed groups increased relative to those in the control group. Therefore, the $Ag^+$ ions in commercial nanometer sized silver could accumulate in aquatic environments and seriously damage the development of zebrafish embryos.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.45-52
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• 2010

The purpose of this study is application to flame retardant powder coating(FRPC) material consisting of ammonium polyphosphate(APP) and magnesium hydroxide($Mg(OH)_2$) as a halogen free flame retardant into thermoplastic resin(LDPE-g-MAH). For improvement of adhesion, LDPE-g-MAH was synthesized from low density polyethylene(LDPE) and maleic anhydride(MAH). The mechanical properties as melt flow index, pencil hardness, cross-hatch adhesion and impact resistance of FRPC were measured. Also, the limited oxygen index(LOI) values were measured 17.3vol%, 31.1vol% and 33.7vol% for LDPE-g-MAH, FRPC-3(APP 15wt%, $Mg(OH)_2$ 15wt%) and FRPC-5(APP 30 wt%), respectively. The thermo gravimetry/differential thermal analysis(TG/DTA) of FPRC-3 was observed endothermic peak at $340^{\circ}C$ and $450^{\circ}C$, it was confirmed predominant thermal stability though the wide temperature range by APP and $Mg(OH)_2$. It was showed V-0 grade for FRPC-3 and FRPC-4(APP 20wt%, $Mg(OH)_2$ 10wt%) that a char formation and drip suppressing effect, and combustion time reduced by UL94(vertical burning test). It was confirmed that flame retardancy was improved with the synergy effect because of char formation by APP and $Mg(OH)_2$.

• Journal of Embryo Transfer
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• v.23 no.1
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• pp.1-4
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• 2008

This study was performed to investigate the effect of laser-assisted hole in the zona pellucida (ZP) of frozen-thawed ICR mouse embryos on the process of hatching that is critical for expanded blastocysts to implant into endometrium, Vitrification medium, composed of ethylene glycol and sucrose supplemented with 7.5% (w/v) PVP, was used to freeze $2{\sim}4$ cell stage embryos recovered from oviducts of superovulated and mated female mice before storing them in $LN_2$. Right after thawing them, a laser beam was shot to make a hole in ZP followed by culturing in KSOM for $96{\sim}120\;hr$ and examining development to blastocyst and hatching every 12 hr. Laser-treated embryos showed significantly higher hatching rate compared to control (92.9% vs. 22.1%, p<0.05). From around Day 4, blastocysts developed from laser-treated embryos started hatching while the blastocysts of control group failed to hatch showing a lot of shrinkage. This study shows that a laser-assisted hole in ZP improves the hatching rate of blastocysts developed from frozen-thawed, in vitro cultured ICR mouse embryos.

• Journal of Life Science
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• v.13 no.2
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• pp.150-153
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• 2003

To determine the effect of newly developed insecticide on two spotted spider mite, Tetranychus Urticae, populations, ten leaf discs were sprayed with three different concentrations (0.5%, 1.0%, and 1.5%) of the tested insecticide solution, and with a water-sprayed control. The tested insecticide solution was toxic to adult female and immature of two spotted spider mite, but was relatively non-toxic to eggs. For equivalent concentrations, more adult females were killed than immature stages. There was no marked difference between the hatch of treated and untreated eggs, although a weak trend between the numbers of unhatched eggs and the insecticide concentration after 7 days is shown.

• International Journal of Industrial Entomology and Biomaterials
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• v.37 no.2
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• pp.90-94
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• 2018

In the present study, we investigated the effects of temperature and photoperiod on oviposition of Protaetia brevitarsis. The effects of long- and short-day cycles on oviposition and egg hatching of P. brevitarsis were investigated at different temperatures. Three male-female pairs were confined to oviposition chambers maintained at $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, and $35^{\circ}C$, with 16L:8D and 8L:16D photoperiod. Oviposition was observed at all temperatures. The total number of eggs laid per female was between 46.8 and 110.8, and the optimal temperature for oviposition and fertility was between $20^{\circ}C$ and $30^{\circ}C$. Furthermore, it was difficult for the eggs to hatch at $35^{\circ}C$. Fewer eggs were laid under short photoperiod than under long photoperiod at all temperatures. Hatching success was 93.5% at $20^{\circ}C$, 90.9% at $25^{\circ}C$, 71.5% at $30^{\circ}C$ and 37.3% at $35^{\circ}C$ under long-day(16L:8D) condition and Temperature had a strong effect on the time to hatching. Neither oviposition nor subsequent egg hatching was influenced by photoperiod and temperature. The information obtained will be useful for mass rearing P. brevitarsis.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.257-263
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• 2002

This study was carried out not only to investigate the toxicities of 12 registered insecticides on different developmental stages, but also to determine the sublethal effects on longevity and reproduction of newly emerged adult female and development of the next generation in the rice skipper, Parnara guttata. Fenitrothion, fenthion, cartap hydrochloride, ethofenprox highly suppressed egg-hatch. All insecticides treated showed high larvicidal activity on the 1st to 2nd instar larva. The insecticides showed higher larvicidal activities on the 5th instar larva were fenitrothion, fenthion, ethofenprox, fipronil, methoxyfenozide, tebufenozide and Bt. var. kurstaki. The sublethal doses of fenthion, tebufenozide, cartap hydrochloride, methoxyfenozide, ethofenprox, imidacloprid and fipronil shortened the longevities of newly emerged adult female from the treated larva ($3{\sim}4$ instar). BPMC, imidacloprid, ethofenprox, fipronil and methoxyfenozide delayed the preoviposition periods of adult females and decreased the number of eggs laid when they were treated at the larval stages of the previous generation. Ethofenprox caused severe sublethal effects on P. guttata offspring, completely blocking the production. All insecticides except fenitrothion affected the egg viability, and all eggs from the adult females emerged from the survivors treated larvae with imidacloprid or fipronil fail to hatch. IGRs, methoxyfenozide and tebufenozide showed an adverse effect on the development of next generation larva.

• Korean journal of applied entomology
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• v.49 no.2
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• pp.129-137
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• 2010

Four major agricultural insect pests, Bemisia tabaci, Myzus persicae, Plutella xylostella and Tetranychus urticae, were irradiated with 30, 50, 70, or 100 Gy electron-beam. Longevity, egg hatching, emergence, and fecundity of the test insects were measured. Hatchability of B. tabaci, P. xylostella and T. urticae declined with increasing irradiation doses, and all B. tabaci and T. urticae eggs were dead at 100 Gy. When eggs of B. tabaci, P. xylostella and T. urticae were irradiated, hatch was inhibited. B. tabaci adults grown from 70 Gy irradiated eggs did not lay eggs. Fecundity of P. xylostella from the 100 Gy irradiated eggs decreased. When B. tabaci, P. xylostella, M. persicae and T. urticae nymphs/larvae were irradiated, the results were similar as those of the hatched eggs. When P. xylostella pupae were irradiated with 100 Gy, fecundity of emerged adults decreased and no eggs hatched. When B. tabaci, P. xylostella, M. persicae and T. urticae adults were irradiated with 70 and 100 Gy, fecundity decreased and egg hatch of B. tabaci was inhibited. However, the longevity of adults did not change and electron-beam irradiation of all developmental stages had no effect on the longevity of adults.