• 제목/요약/키워드: juvenile period

검색결과 237건 처리시간 0.02초

Zebrafish 발생기에서 $TiO_2(P-25)$ 나노 입자의 생물 독성 (Bio-toxicity of Titanium Dioxide Nano Particles (P-25) in Zebrafish Development Stage)

  • 여민경;조윤희
    • Environmental Analysis Health and Toxicology
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    • 제22권3호
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    • pp.189-196
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    • 2007
  • [ $TiO_2$ ] is widely used because it is non-toxic. Recently, however, nanometer size $TiO_2$ particles (P-25) have been produced and used to increase the photo catalysis efficiency. Nanometer-sized $TiO_2$ is efficient, but due to its small size ($20{\sim}30\;nm$), it can flow into ecosystems and into cells. Thus, it may affect human health. Additionally, $TiO_2$ can produce a second contaminant, OH-radical, which is a health risk for all living organisms during photo degradation reaction. Hence, when nanometer-sized $TiO_2$ flows into natural streams and attaches to living organisms, it will create health risks. We investigated the biological toxicity of this condition in zebrafish embryos. We observed abnormal morphology, hatching rate, and measured the catalase activity to determine anti-oxidation at 100 post fertilization hours. Zebrafish were somewhat affected by $TiO_2$ nanometer sized particles under UV-A (a condition similar to sunlight). Powdered $TiO_2$ is toxic to the zebrafish fly. Even without light, $TiO_2$ particles attached to embryos and flies, having an effect on both.

Analysis of Polymeric Immunoglobulin Receptor Expression in Olive Flounder (Paralichthys olivaceus) against Viral Hemorrhagic Septicemia Virus

  • Kyung-Hee Kim;Sulhye Park;Jong-Won Park;Minhwan Jeong;Julan Kim;Hyejin Kim;Jeong-Ho Lee;Dain Lee
    • 한국발생생물학회지:발생과생식
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    • 제27권2호
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    • pp.67-75
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    • 2023
  • Polymeric immunoglobulin receptor (pIgR) mediates the transfer of polymeric immunoglobulin to protect organisms and is one of the most important mucosal effectors. In this study, the developmental stage- and tissue-specific expression of pIgR were observed before virus inoculation in olive flounder. pIgR was gradually expressed until the formation of immune tissue, exhibiting high expression in the late juvenile period; thereafter, pIgR expression gradually decreased and exhibited high expression in the spleen and skin. Moreover, pIgR expression after viral hemorrhagic septicemia virus infection was high in the kidney and spleen tissues at high density and low at low density. The results of this study can provide a basis for future studies on breeding density, virus expression, and immune system studies in fish.

낙동강 수계 위천에 서식하는 큰납지리(Acheilognathus macropterus) (Pisces : Cyprinidae)의 초기생활사 (Early Life History of Acheilognathus macropterus (Pisces:Cyprinidae) in the Wicheon Stream of Nakdonggang River)

  • 박재민;한경호
    • 한국수산과학회지
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    • 제56권5호
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    • pp.676-683
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    • 2023
  • The development of the egg, larvae, and juveniles of Acheilognathus macropterus from the Wicheon stream of Nakdonggang River was investigated for early life history characteristics. The fish used in the study were collected from Wicheon stream located in Bian-myeon, Uiseong-gun, Gyeongsangbuk-do. The fertilized egg was 1.88±0.09 mm (n=30) in long diameter and 1.34±0.06 mm (n=30) in short diameter. After fertilization at a water temperature of 20℃, the egg took 31 h and 40 min to hatch. Newly hatched larvae had an average total length of 3.92±0.13 mm (n=30) and possessed a yolk sac the mouth and anus were not developed. Twenty days after hatching, the postflexion larvae had an average total length of 8.08±0.29 mm (n=30), with the tail tip fully bent at 45° and began feeding. Thirty-three days after hatching, the number of fin stems reached an integer with an average total length of 15.0±1.08 mm (n=30). In this study, differences in the egg size, hatching time, melanophore development period, and distribution location were confirmed between A. macropterus and allied species.

과수육종에 있어 생명공학의 이용 전망 (The Prospectss and Utilization of Biotechnology for the Improvement of Fruit Breeding)

  • 이돈균;김휘천;신용억;강상조;예병우
    • 한국식물학회:학술대회논문집
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    • 한국식물학회 1995년도 제9회 식물생명공학 심포지움 식물육종과 분자생물학의 만남 The 9th Plant Biotechnology Symposium -Breeding and Molecular Biology-
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    • pp.133-170
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    • 1995
  • The major objectives of fruit breeding lie in improvement of cultivar, easy to be cultivated and of high quality, in order to produce unexpensive, delicious fruit both for fresh fruit market and processing. Recently, fruit breeding in Korea has contributed to breeding of several superior cultivars in major fruit crops, resulting in appreciable improvement in qualities such as skin color, taste and fruit-bearing habit concerned with productivity. In spite of accomplishments mentioned above, the need for both highly disease-resistant cultivars and long-keeping, physiological disorder-resistant cultivars to meet long distance transsportation in the temperate fruit crops of apples, oriental pears, stone fruits such as peaches, and grapes grown in Korea is rapidly pressing more than ever, as cultivars of today susceptible to pests and diseases and vulnerable to physiological disorders are very expensive and time-consuming in post-harvest handling and management. Thus, imporvements made in the above problems through breeding level will lead to the really enhanced productivity in fruit industry. The major impediments of tree size, the long length of juvenile period and the highly heterogeneous genetic composition to the improvement of fruit crops are responsible for the lower amount and rate of improvements of fruit crops as compared to annuals. Considering the expected limitations of the above problems to be solved through conventional breeding methods and strategy, a turning point of breeding a near perfect cultivar would be laid down if innovative breakthroughs in biological technology will be realized in applying some of the techniques of genetic manipulation at the molecular level to the cultivar improvement of fruit crops, such as the selective insertion of DNA carrying genes that govern desirable characteristics. More than anything else, those traits such as fruiting habit deciding productivity, elements of fruit qualities conditioned by monogene, and disease-and pest-resistance of vital importance for successful fruit growing are urgently desired to be improved by advancement of biotechnology for they are more than difficult and need long period to be attained through conventional breeding method.

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넙치 전 암컷 집단의 생산을 위한 연구 IV. 성분화 기간 중 수온에 의한 성 결정 (Studies on the Production of All-Female Populations of Olive Flounder, Paralichthys olivaceus IV. Sex Determination by Water Temperature During Sex Differentation Period)

  • 김경길;방인철;김윤
    • 한국양식학회지
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    • 제9권4호
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    • pp.429-435
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    • 1996
  • 사육 수온이 넙치의 성비에 미치는 영향을 조사하기 위해 일반 넙치 및 자성발생성 2배체 넘치 자어를 대상으로 부화 후 35일(전장 1.2 cm)부터 100일(전장 12 cm)까지 사육 수온 18, 21, 24 및 $27^{\circ}C$로 나누어 2회 반복하여 실험하였다. 사육 수온이 높을수록 암컷의 비율은 낮게 나타나 사육 수온과 암컷 비율에 있어 역상관관계를 보였다. 자성발생성 2배체 실험군의 경우 $18^{\circ}C$에서 $94.4\%$의 암컷을 보인 반면 $27^{\circ}C$에서는 $57.6\%$로 나타나 암수비가 1 : 1이었다(P<0.01). 사육 수온에 따른 생존율은 일반 넙치 및 자성발생성 2배체 넙치 모두 18, 21, 24 및 $27^{\circ}C$ 순으로 높았으나 $27^{\circ}C$를 제외한 나머지 실험군은 유의차가 없었으며 $18^{\circ}C$를 제외한 나머지 실험군의 체중 성장은 유의차가 없었다(P>0.05).

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여성건강 간호연구의 최근 동향 (Recent Trends in the Nursing Research on the Woman's Health)

  • 고효정;정금희;박경민;김혜영
    • 여성건강간호학회지
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    • 제3권2호
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    • pp.238-249
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    • 1997
  • For the purpose of improving the nursing research on the woman's health the nursing papers form Korea were analyzed by subject and content. This work was anticipated to suggest the direction of the research on the filed of woman's health. A total of 420 papers form journals, TaeHan KanHo, Journal of Academy of Nursing, and Journal of Korean Woman's Health Nursing Academic Society published from 1992 to 1996 were analyzed by Dubar and Patterson's criteria. The Number of papers on the woman's health was 66(15.7%), and those of mother's role and other clinical studies were 36(8.6%) and 318(75.7%) each. Special fields of the 66 papers on the woman's health and its number were health management 27(40.9%), psychiatric health 15(22.7%), postmenopausal period 5(7.6%), sex 5(7.6%), menstruation 4(6.1%), abortion 3(4.5%), nursing need 2(3.0%), violence 1(1.5%) respectively. Considering the subjects according to the life cycle, the subject on pregnant and middle aged period were more frequent than that on juvenile, peripartum, married or aged periods. According to above results, the proposals for promoting the nursing research were followings : Woman should be included as a subjects more frequently in general nursing research. The methodology for comparison study on the sex difference should be developed to understand the multifaced phenomena of woman's health. The factor analysis affecting the woman's health inadequately should be done.

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Prognostic factors for survival of dogs infected with canine parvovirus

  • Pak, Son-il;Hwang, Cheol-young;Han, Hong-ryul
    • 대한수의학회지
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    • 제39권4호
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    • pp.838-845
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    • 1999
  • To determine the prognostic factors for survival of dogs infected with canine parvovirus, clinical and laboratory data of 35 dogs with clinical signs compatible with canine parvoviral enteritis admitted to the Veterinary Medical Teaching Hospital, Seoul National University during the period 1997-1998 were collected. Dogs were grouped by some major covariates, which can be considered as guides to the relative prognosis of dogs in the different subgroups. The Kaplan-Meier survival analysis and Weibull proportional hazard model were used to estimate overall survival, evaluate the comparability between groups, and identify potential prognostic factors. The overall survival rate for all dogs was 45.7% over the study period, and the Kaplan-Meier estimate of one week survival was 0.4989. Gender was the most favorable prognosis ; male dog (median, 6 days) had significantly higher risk of dying than female dog (median, 17 days ; p = 0.0023). In addition to gender, age was significantly associated with survival, with juvenile dogs less than 6-month-old having higher risk (p = 0.0359). Dogs that vaccinated with complete protocol (p = 0.0374) and those of having higher value of mean corpuscular volume (p = 0.0346) were found to be of prognostic importance. The 7 dogs in which white blood cell count of less than 2000 had shorter median survival time (3 days) than the remaining 28 dogs (8 days), but no statistical significance was found between leukopenic and survival. The distribution of packed cell volume and hemoglobin measurement was such that the overall risk of dying in the two groups was comparable. Further studies are needed to more accurately assess these results.

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Antijuvenoid Action of Terpenoid Imidazole Compound on Larval - Pupal - Adult Development of Silkworm, Bombyx mori L.

  • Saha, Atul Kumar;Datta (Biswas), Tapati;Das, Salil Kumar;Kar, Niharendu Bikash
    • International Journal of Industrial Entomology and Biomaterials
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    • 제14권2호
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    • pp.127-135
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    • 2007
  • Precocious metamorphosis was induced in two popular bivoltine breeds i.e. YB and $NB_4D_2$ by an imidazole compound having anti-juvenile hormone activity. The chemical was administered by feeding treatment with mulberry leaf to freshly moulted (0-6 hrs) IV instar larvae. The dose of the chemical was found to be breed specific being 650 ppm for YB and 500 ppm for $NB_4D_2$. The chemical caused complete skipping up of the fifth instar larvae which is most susceptible to diseases. But IV instar was somewhat prolonged. As a result the total larval period was reduced by 4-5 days. However, some of the rearing and reeling parameters like cocoon yield, cocoon weight, shell weight, shell %, filament length and fecundity were reduced for that particular generation only. The effective rate of rearing (ERR %) was significantly increased in trimoulters during the most unfavourable August - September seed crop season. Number of cocoons / kg and number of male moth were significantly higher in trimoulters. These may be useful for preparation of $multi{\times}bi$ hybrid seed. Fine denier was also found in trimoulter cocoon which is the cause of getting fine silk filament from trimoulter cocoons. Normal mating behaviour and emergence pattern was recorded in trimoulters. Bivoltine trimoulter males also showed competence for mating with multivoltine females. These results suggest the possibility of getting trimoulter males during hot and humid seasons when rearing of bivoltine is almost impossible particularly in Eastern and North Eastern India.

A Study on the Actual Conditions of Brassiere Wearing for Girl Students

  • Sohn, Hee-Soon;Cha, Su-Joung
    • 패션비즈니스
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    • 제9권6호
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    • pp.12-28
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    • 2005
  • The purpose of this study is to help develop high quality brassieres with functionality and comfort, fitting adolescents' physical features during their growth period. This study conducts a comparative analysis of juvenile brassiere and adult brassiere to identify the problems of brassieres in the market. The raw data for this study was processed by SPSS 10.1. The results of this study are summarized as follows: 1. The results of this survey show that the girls' satisfaction of their breasts has correlations between breast protrusion degree and volume. The girls think that if they have protrusive breasts their breast volume is big, and their breast satisfaction level shows high. 2. The results show that the objective of brassiere wearing is to prevent breasts sag and rupture, make good breast shape, balance their entire body shape, and make beautiful outer garment line. Brassiere functions are to prevent jiggle of breasts, make a good body line, and cover the nipples. For the grader school students, they are wearing brassiere to make a good balanced body and as their breasts developed, they are wearing brassiere for beautiful body shape not just to cover up their breasts. 3. In regard to brassiere cup size recognition, as students have higher grade at school, they have better recognition abouxt their cup size. As they are better aware of their cup size, they have better satisfaction with their cup size. Therefore, choosing the right size of brassiere for their bust is very important. 4. Girl students' brassiere preference shows that 317 students (56.9%) prefer white for brassiere colors, following pink and flesh color. Their most preferred brassiere material is cotton (354 people, 63.6%) because cotton is not sensitive even for weak skin. For brassiere style, 273 students (49%) prefer round style, following spots and mold. Their most preferred brassiere style is stake. In addition, brassiere should not press their breasts because their breasts are developing during puberty period.

한강 수계 보통천에 서식하는 좀구굴치 Micropercops swinhonis의 난발생 및 자치어 형태발달 (Morphological of Development Eggs, Larvae and Juveniles Micropercops swinhonis in Botongcheon Stream Hangang River)

  • 박재민;한경호
    • 한국어류학회지
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    • 제35권3호
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    • pp.151-159
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    • 2023
  • 이 연구는 한강 수계 보통천에 서식하는 좀구굴치의 초기생활사를 규명하고 근연종과 유연관계를 비교하였다. 좀구굴치의 수정란은 타원형으로 평균 난경은 장경 1.23 mm, 단경 0.85 mm 였다. 수온 20.6℃에서 부화 시간은 179시간이 소요되었다. 부화자어의 크기는 전장 3.82~4.08 mm로 입과 항문이 완전히 발달하지 않았다. 후기자어기는 부화 후 18일째 전장 7.97~8.43 mm로 척색말단 끝부분이 45°로 완전히 휘어졌다. 치어기는 부화 후 29일째 전장 9.83~10.8 mm로 지느러미 줄기 수는 정수에 달하였다. 연구 결과 좀구굴치는 난 크기, 부화자어 크기, 유영형태에서 근연종과 차이를 보였다. 후기자어 이행시기와 제1등지느러미 발달 시기는 비교한 근연종 중 가장 느렸고, 크기는 큰 특징을 보여 초기생활사에서 근연종과의 차이점을 확인할 수 있었다.