• 제목/요약/키워드: Early Stage

검색결과 7,542건 처리시간 0.038초

카드뮴이 양서류의 체축 형성에 미치는 독성 효과 (Toxic Effect of Cadmium on the Amphibian Axis Formation)

  • 김윤경;정해문
    • Toxicological Research
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    • 제11권1호
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    • pp.37-42
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    • 1995
  • Effect of cadmium on the early amphibian development was analyzed through FETAX (Frog Embryo Teratogenesis Assay: Xenopus). Embryos manifested concentration-dependent mortality and realformations; shortage of anterior-posterior axis gut realformation, ocular anomalies, bent notochord, misshapen dorsal fin, and derreal blisters. The treatment with 1.5ppm cadmium solution caused 100% mortality and concentration of lppm did not kill the embryos that caused 100% anomaly. The teratogenic index (TI = LC50 /EC50) was 2.8 indicating that $CdCl_2$ is teratogenic for Xenopus laevis. Embryos that were pulsetreated with at early to late blastula stage (St. 3-9) and mid to late blastula stage (St. 6-10) showed relatively strong resistance to cadmium, but the embryos treated at gastrula stage (St. 10-13) showed high mortality. And the embryos treated at tailbud stage (after St. 25) showed highest mortality of any other early stages. Effects of temperature were studied through pulse- treatment during gastrula stage at $20^{\circ}C$ and $30^{\circ}C$. The embryos treated with 7.5ppm at $30^{\circ}C$ and 15ppm at $20^{\circ}C$ caused 100% mortality respectively, indicating that higher temperature had more severe toxic effect. One of the most peculiar effect of cadmium at gastrulation was distortion of the tail. The probable cause of toxic effect of Cd was discussed.

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설계 초기 단계에서 BIM 모델과 물리적 모델의 상호작용 방안 (Interaction between BIM Model and Physical Model During Conceptual Design Stage)

  • 이인근;김성아
    • 한국통신학회논문지
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    • 제38C권4호
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    • pp.344-350
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    • 2013
  • 초기 디자인 단계에서 효율적인 디자인 의사결정을 위해서는 지오메트리에 대한 고려가 필수적이다. 하지만 중요한 의사결정은 지오메트리에 대한 효율적 분석이 가능한 BIM모델 보다는 여전히 대화나 물리적 모델, 제스처를 통해 이루어진다. 본 논문은 실시간 BIM분석을 위한 BIM 모델과 물리적 모델의 연동을 제안한다. 두 모델이 실시간으로 연결되는 시스템 프레임워크를 통해 건축가는 디자인 초기 단계에서 부터 BIM 모델을 효율적으로 활용할 수 있다. 이 프레임워크는 건축가들이 설계 초기 단계에서부터 마지막 단계까지 컴퓨터의 기술을 활용한 동적인 의사결정을 가능하게 한다.

3차원 선박형상정보를 활용한 설계초기단계 용접물량 산출 (Estimation of Welding Material Quantity for Shipbuilding at Early Design Stage based on Three-dimensional Geometric Information)

  • 이정훈;변석호;남종호;강태원
    • 대한조선학회논문집
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    • 제54권1호
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    • pp.57-62
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    • 2017
  • These days, shipbuilding companies are making an effort to adopt the IT technology in order to improve the production efficiency. One such effort is to utilize a planning and scheduling system to predict the production cost in advance. In this system, assessing the welding material quantity is an important factor. Unfortunately, obtaining the welding material quantity in the early design stage is extremely difficult because the detailed production information, which is essential in deriving the cost associated with welding, is normally available at a later stage. This paper aims at developing a computerized program that produces an index to estimate the welding material quantity in the early design stage. By using only three-dimensional geometric information, the program analyzes the production process and estimates the welding material quantity at any design or production stage when no production information is available. The results can be used for the planning and scheduling system.

Influence of Cooling Rate, Developmental Stage and Addition of Sugar on Cryopreservation of Pearl Oyster (Pinctada Fucata Martensii) Larvae

  • Park, Youn-Hee;Chang, Young-Jin
    • 한국수정란이식학회:학술대회논문집
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    • 한국수정란이식학회 2002년도 국제심포지엄
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    • pp.103-103
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    • 2002
  • This study was conducted to investigate cryopreservation of pearl oyster, Pinctada fucata martensii larvae. Four cooling rates (-0.25, -0.5, -0.75 and -1.0$^{\circ}C$/min.) were used to examine a proper cooling rate during cryopreservation of trochophores before seeding temperature (-12$^{\circ}C$). Seven developmental stages (early and late trochophores, early and late D-shaped larvae and early, middle and late umbo stage larvae) and different sugars (fructose, glucose and sucrose) were used to investigate optimal larval stage and effective sugar in cryopreservation of larvae. The survival rates of frozen-thawed trochophores increased at cooling rate of -1.0$^{\circ}C$/min. As larval developing, survival rate of frozen-thawed larvae increased, except umbo stage larvae, and especially late D-shaped larvae highly survived as 91%. Addition of sugar revealed positive effect on cryopreservation in this experiment and 0.2 M glucose and sucrose mixed with 2.0 M dimethyl sulfoxide significantly enhanced survival rate of larvae (P<0.05). The results of our study indicate that desirable cooling rate, developmental stages of larvae and effective sugar far cryopreservation of pearl oyster, P. fucata martensii larvae are -1$^{\circ}C$/min, late D-shaped larvae and 0.2 M glucose and sucrose, respectively.

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멸치를 첨가한 김치의 물리화학적 및 관능적 특성 (Physicochemical and Sensory Characteristics of Anchovy Added Kimchi)

  • 문갑순;류복미;전영수;송영선
    • 한국식품영양과학회지
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    • 제25권3호
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    • pp.460-469
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    • 1996
  • This study was intended to observe the physicochemical and sensory characteristics of anchovy added kimchi during fermentation at 4$^{\circ}C$ for 4 weeks. Salting of Chinese cabbage for 10 hours at 10% brine solution was turned out to be appropriate organoleptically for kimchi preparation. Salt content of all kimchies prepared in this study was below 2%. The changes of pH and acidity during fermentation was slow in raw anchovy added kimchi compared to other kimchies. The content of vitamin C was not changed significantly through the fermentation period, whereas the content of reducing sugar was increased at the early stage of fermentation and subsequently decreased as fermentation proceeded. The number of lactic acid bacteria was the highest in raw anchovy added kimchi. The content of calcium and phosphorus were higher in anchovy powder added kimchi and raw anchovy added kimchi than control. In the early stage of fermentation, the major pigments of kimchi were the chlorophyll and carotenoid, but in the later stage of fermentation, the color of Chinese cabbage became greenish brown as chlorophyll was converted to pheophytin. In sensory evaluation test, raw anchovy added kimchi received high score at the early stage of fermentation and anchovy powder added kimchi at the late stage of fermentation, respectively.

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Mature and Bi-Sexual Phase Gonad Occurrence in Cultured Red Spotted Grouper, Epinephelus akaara

  • Hwang, In Joon;Min, Byung Hwa;Baek, Hea Ja
    • 한국발생생물학회지:발생과생식
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    • 제24권3호
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    • pp.225-230
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    • 2020
  • This study reports the presence of mature and bi-sexual phase gonads in red spotted grouper, Epinephelus akaara after less than a year of cultivation in a commercial indoor tank and a net cage. In December 2018, juveniles were placed in an indoor tank and cultured for five months. In June 2019, the fish were transferred to a net cage and cultured until September. The rearing temperatures ranged from 19.86℃-24.65℃ in the indoor tank and 21.86℃-27.65℃ in the net cage. During the net cage culture period, specimens were randomly selected for histological gonad examination. The highest gonadosomatic index (GSI) value was measured in July (3.38±2.53), and dramatically decreased in August (0.44±0.21) and September (0.42±0.30). In July, some mature fish showed signs of vitellogenic stage oocyte development (vitellogenic and oil droplet stage oocytes), but immature fish were in an early developmental stage containing peri-nucleolus stage (PNS) oocytes. Bi-sexual phase gonads containing spermatocytes and spermatids were observed in the lumen and several PNS oocytes. By August and September, most specimens showed early-stage ovary development. However, mature testis (in August) and bi-sexual phase gonads (in September) were also observed. These results provide evidence for early puberty and hermaphroditism in the red spotted grouper.

코먼레일 직접분사식 디젤 엔진의 조기 분사가 연소 및 배기특성에 미치는 영향 (Effect of Early Injection Strategy on the Combustion and Emission Characteristics of the Common-rail DI Diesel Engine)

  • 윤승현;김명윤;김대식;이제형;이창식
    • 한국자동차공학회논문집
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    • 제14권4호
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    • pp.26-31
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    • 2006
  • An experimental investigation of an early injection strategy was conducted on a small single cylinder common-rail DI diesel engine to reduce the oxides of nitrogen($NO_x$) emission. The main objectives of this study were to investigate the emissions, performance and combustion characteristics in a diesel engine with early and two-stage injections. The two- stage injection was conducted to reduce the wall-wetting of early injected fuels on the cylinder wall or to promote the ignition of premixed charge. The engine test was performed at conditions of 1500rpm, injection timing ranging from TDC to BTDC $80^{\circ}$. The experimental results show that $NO_x$ emissions were decreased in both cases of early injection and two stage injection compared to the conventional diesel combustion by the near TDC injection. However, soot and products of incomplete products (i.e. HC and CO) are slightly increased. Also, the second injection near TDC promoted the ignition of premixed fuel, therefore, IMEP was increased.

Adaptive Transition of Aquaporin 5 Expression and Localization during Preimplantation Embryo Development by In Vitro Culture

  • Park, Jae-Won;Shin, Yun Kyung;Choen, Yong-Pil
    • 한국발생생물학회지:발생과생식
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    • 제18권3호
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    • pp.153-160
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    • 2014
  • Adaptive development of early stage embryo is well established and recently it is explored that the mammalian embryos also have adaptive ability to the stressful environment. However, the mechanisms are largely unknown. In this study, to evaluate the possible role of aquaporin in early embryo developmental adaptation, the expression of aquaporin (AQP) 5 gene which is detected during early development were examined by the environmental condition. To compare expression patterns between in vivo and in vitro, we conducted quantitative RT-PCR and analyzed localization of the AQP5 by whole mount immunofluorescence. At in vivo condition, Aqp5 expressed in oocyte and in all the stages of preimplantation embryo. It showed peak at 2-cell stage and decreased continuously until morula stage. At in vitro condition, Aqp5 expression pattern was similar with in vivo embryos. It expressed both at embryonic genome activation phase and second mid-preimplantation gene activation phase, but the fold changes were modified between in vivo embryos and in vitro embryos. During in vivo development, AQP5 was mainly localized in apical membrane of blastomeres of 4-cell and 8-cell stage embryos, and then it was localized in cytoplasm. However, the main localization area of AQP5 was dramatically shifted after 8-cell stage from cytoplasm to nucleus by in vitro development. Those results explore the modification of Aqp5 expression levels and location of its final products by in vitro culture. It suggests that expression of Aqp5 and the roles of AQP5 in homeostasis can be modulated by in vitro culture, and that early stage embryos can develop successfully by themselves adapting to their condition through modulation of the specific gene expression and localization.

중령에 따른 측두하악관절내 탄력섬유의 분포에 관한 연구 (A Histological Study on Age Changes of the Elastic Fibers of Temporomandibular Joint in Icr Mouse)

  • Jin-Pyo Lee;Jung-Pyo Hong
    • Journal of Oral Medicine and Pain
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    • 제19권1호
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    • pp.125-136
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    • 1994
  • Observation of elastic fiber's change of mouse TMJ due to several round factor, principally external stimulations, their influence on the TMJ structure's change and the analize of the consecutive evolution of the disease in most important. So, the author believe that the factor of TMJ feature is the elastic feature's change and it's the principal factor of the TMJ disease. For observation of the increase and disposition of elastic fiber that to regulate the elastic feature of tissue and allow it existence. For this propose, observation with histologic methods on 20mouse ICR of 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. The results were as follow : 1. In the early stage, the condyle of TMJ is originated from cartilage mass, and it's calcification is endochondral. 2. In the early stage, the disc is relatively thin and immature, but in the later stage the fiber is dense and the disposition is most functional. 3. Observation of the early stage, the elastic fiber is a thin fiber that to across antero- posterior direction, but in the later stage elastic fiber are developed, the disposition that in the early stage was perpendicular to articular surface, now in parallel. 4. The elastic fiber was observated most clearly in the retrodiscal tissue. 5. In conclusion, the elastic fiber is observed like a thin fiber 1 week from born, but the fiber to increase the weight and it dispose functionally, and 4 week from born, it can realize the normal function.

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The Optical and IR Properties of Peculiar early-type galaxies from Stripe82 and WISE Data

  • 홍주은;임명신
    • 천문학회보
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    • 제37권2호
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    • pp.90.2-90.2
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    • 2012
  • Galaxy merging plays a important role to the formation and evolution of galaxy. Early-type galaxies are believed to be formed by galaxy merging. We combined 3 color images in g,r,i band using Stripe82 image of which the surface brightness is 2 mag deeper than that of SDSS image. We classified early-type galaxies which have the merging features, the evidence of galaxy mergers through careful visual inspection. We investigated the IR properties of early-type galaxies with the merging feature using WISE data. We analyzed the star formation according to the type of galaxy. Early-type galaxies with the merging feature show the higher star formation than non-merging galaxies, but the difference is not significant. This results implies that quite a few early-type galaxies might be formed by dry merger, not wet merger. Meanwhile, the most of ULIRGs show tidal tail, on the other hand, early-type galaxies show tidal tail including shell structure. It suggests that ULIRGs have more gas and it might be in early stage of galaxy merging, early-type galaxies might be in the late stage of galaxy merging.

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