• 대한수의학회지
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• 제38권3호
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• pp.652-658
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• 1998

The efficiency of nuclear transfer using donor embryos originated from ovum pickup(OPU) and activated recipient cytoplasts were examined for induction of twinning in Korean native cattle(KNC). After aspiration of follicle by OPU, regardless of the vacuum applied, we obtained same result in proportions of recovered cumulus-oocyte complex (COCs) with compact cumulus. Under electric stimulation(1.0kV/cm DC for $40{\mu}s$), most of activated oocytes proceed to anaphase II/telophase II within 3h(84.7%). In the treatment of oocyte activation, the preactivation which was performed before fusion had significant effect on the developmental rates to morula/blastocyst stage(9.4 vs 4.0%). In embryo transfer of nuclear transferred embryos, we obtained 2 twins from KNC recipients and 1 twin from a Holstein recipient. Our results showed that it is possible to obtain twins using nuclear transfer technique in KNC.

• 자원환경지질
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• 제29권1호
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• pp.11-21
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• 1996

The first Mg-skarn minerals are found from magnetite ore deposits of the Janggun mine, Korea. The skarn minerals are composed of mostly chondrodite, olivine， chlorite, serpentine, phlogophite, talc, apatite, magnesite， dolomite, siderite and trace amount of clinopyroxene, amphibole, garnet, wollastonite associated with magnetite, pyrrhotite and pyrite. The skarn zone is developed in the magnetite deposits at the contact of the Mg-rich Janggun Limestone Formation and the Chunyang granite. The chondrodites are columnar and radial shapes and some of them show twins. The chemical compositions of twinning-type chondrodites have high FeO (4.63 to 5.6 wt%), MnO (0.26 to 0.46 wt%) and low MgO (55.02 to 56.18 wt%) relative to the radial-type chondrodites. Twinning in chondrodite has been formed in close relation to substitution between Mg and Fe + Mn in humite solid solution. Temperature, $-logfo_2$ and $X_{CO2}$ during the skarn stage of magnetite deposits from the Janggun mine range from 395 to $430^{\circ}C$, from 30.5 to 31.2 atm and from 0.06 to 0.09, respectively.

• 한국재료학회지
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• 제25권5호
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• pp.221-225
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• 2015

In-situ neutron diffraction has been employed to examine the effect of strain path on lattice strain evolution during monotonic and cyclic tension in an extruded Mg-8.5wt.%Al alloy. In the cyclic tension test, the maximum applied stress increased with cycle number. Lattice strain data were acquired for three grain orientations, characterized by the plane normal to the stress axis. The lattice strain in the hard {10.0} orientation, which is unfavorably oriented for both basal slip and {10.2} extension twinning, evolved linearly throughout both tests during loading and unloading. The {00.2} orientation exhibited significant relaxation associated with {10.2} extension twinning. Coupled with a linear lattice strain unloading behavior, this relaxation led to increasingly compressive residual strains in the {00.2} orientation with increasing cycle number. The {10.1} orientation is favorably oriented for basal slip, and thus showed a soft grain behavior. Microyielding occurred in the monotonic tension test and in all cycles of the cyclic test at an applied stress of ~50 MPa, indicating that strain hardening in this orientation was not completely stable from one cycle to the next. The lattice strain unloading behavior was linear in the {10.1} orientation, leading to a compressive residual strain after every cycle, which, however, did not increase systematically from one cycle to the next as in the {00.2} orientation.

• Clinical and Experimental Reproductive Medicine
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• 제27권3호
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• pp.295-300
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• 2000

Objective: To report three cases of monozygotic twinning after IVF-ET transfer. Methods: Private practice in two different assisted reproductive technology clinics. Results: Three intrauterine monozygotic twin pregnancies occurred after IVF-ET. One of them was complicated by cord entanglement, another is progressing normal pregnancy without complication and the other was had a normal pregnancy without complication and delivered twin by cesarean section. Conclusion: The reported prevalence of multiple gestations in IVF-ET is a approximately 30%, and it is only 2.7% to be monozygotic twinning in IVF-ET. We report three cases of monozygotic twining after IVF-ET.

• Clinical and Experimental Pediatrics
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• 제48권7호
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• pp.685-690
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• 2005

Recently, twinning rate increases in Korea since the early 1990s by delayed marriage and prevailing of assisted reproductive technology. But twin and higher-order multiples are at increased risk for perinatal and neonatal mortality over 5 fold despite of dramatic improvement of perinatal and neonatal care. Because twins are born more prematurely and have lower birth weights than singleton. In addition, twins are at increased risk for cerebral palsy mainly in monochorionic twins due to co-twin fetal death, twin to twin transfusion and congenital anomaly. So, this article reviews the factors contributing to the mortality and morbidity of the twins and the efforts to decrease the neonatal mortality of twins.

• 한국수정란이식학회지
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• 제8권1호
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• pp.21-24
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• 1993

This study was carried out to investigate the effects of imported 0.25 ml straw frozen semen on fertilizing capacity after artificial insemination. A total of 57 ewes of Corriedale were inseminated at the Namwon Branch, National Anirnal Breeding Institute. Lambing percentage and twinning percentage were 12.3% and 114. 3%, resepectively. Average weight at birth and weaning of 120 days old were 4.5kg and 21.9 kg, respectively. Gestation period was 152.6 days.

• 대한수의사회지
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• 제39권11호
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• pp.1020-1028
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• 2003

We analyzed the records that distribution of the twinning rate, sex of calves and complications of other diseases with twin pregnancy from 10,012 dairy cows for 5-year period from 70 dairy farms in Paju and Goyang cities. Twining rate was increased for 5-

• 한국표면공학회지
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• 제14권3호
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• pp.137-141
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• 1981

니켈 도금의 표면 조직과 두께에 따른 조직의 변화를 투과 전자 현미경을 사용하여 관찰하였다. epitaxial deposit층의 두께는 도금 용액 속에 들어있는 외부 물질에 따라 변화하게 되며, substrate의 결정 방향에 따라 또한 변화한다. (110)면 보다는 (100)면에 도금했을 때 epitaxial deposit 층의 두께가 더 큰 것을 알 수 있었다. non-epitaxial 층으로 변화되는 과정은 hillock의 생성과 계속되는 Twinning에 의해 이루어졌다.

• Corrosion Science and Technology
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• 제18권6호
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• pp.300-311
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• 2019

The corrosion behaviors of twinning-induced plasticity (TWIP) steels with different alloying elements (Cu, Al, Si) in a neutral aqueous environment were investigated in terms of the characteristics of the corrosion products formed on the steel surface. The corrosion behavior was evaluated by measuring potentiodynamic polarization test and electrochemical impedance spectroscopy. For compositional analysis of the corrosion products formed on the steel surface, an electron probe x-ray micro analyzer was also utilized. This study showed that the addition of Cu to the steel contributed to the increase in corrosion resistance to a certain extent by the presence of metallic Cu in discontinuous form at the oxide/steel interface. Compared to the case of steel with Cu, the Al-bearing specimen exhibited much higher polarization resistance and lower corrosion current by the formation of a thin Al-enriched oxide layer. On the other hand, Si addition (3.0 wt%) to the steel led to an increase in grain size, which was twice as large as that of the other specimens, resulting in a deterioration of the corrosion resistance. This was closely associated with the localized corrosion attacks along the grain boundaries by the formation of a galvanic couple with a large cathode-small anode.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3363-3368
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• 2013

Background: The burden due to cancers is an emerging public health concern especially in resource-limited countries like Nigeria. The WHO estimates that cancer kills more people than tuberculosis, HIV/AIDS and malaria combined. As people in Nigeria and other developing countries are beginning to survive infectious diseases, there is an observed epidemiologic transition to chronic diseases, such as cancers. In 2008, 75 out of 1,000 Nigerians died of cancer. Despite the rising incidence and public health importance, Nigeria lacks an organized and comprehensive strategy to deal with cancers. Materials and Methods: This article reviewed 30 peer-reviewed manuscripts on cancer care in four countries. It highlights the limitations to cancer care in Nigeria; due to lack of awareness, low health literacy, absence of organized screening programs, inadequate manpower (in terms of quality and quantity) as well as limited treatment options. Results: This review led to the formulation of a proposal for Nigerian National Cancer Policy, mainly drawn from effective strategies used in Canada, Brazil and Kenya. This is a vertical cancer program that is patient-centered with an emphasis on tobacco control and cancer disease screening (similar to Canada and Brazil). Additionally, it emphasizes primary cancer prevention (similar to Kenya). Its horizontal integration with other disease programs like HIV/AIDS will improve affordability in a poor resourced country like Nigeria. Capacity building for health professionals, hub-and-spoke implementation of screening services, as well as investment in effective treatment options and increased research in cancer care are essential. International 'twinning collaborations' between institutions in richer countries and Nigeria will enhance effective knowledge translation and improve the quality of patient care. Conclusions: A national cancer policy must be developed and implemented in Nigeria in order to overcome the present limitations which help contribute to the observed increases in cancer morbidity and mortality rates. Cancer control is feasible in Nigeria if the nation was to consider and employ some of the cost-effective strategies proposed here.