• 농업과학연구
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• 제43권1호
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• pp.72-79
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• 2016

It has long been known that nutritional and environmental influences during the early developmental period affect the biological mechanisms which determine animal metabolism. This phenomenon, termed 'metabolic imprinting', can cause subtle but long-lasting responses to prenatal and postnatal nutrition and even be passed onto the next generation. A large amount of research data shows that nutrient availability, in terms of quantity as well as quality, during the early developing stages can decrease the number of newborn piglets and their body weight and increase their susceptibility to death before weaning. However, investigation of potential mechanisms of 'the metabolic imprinting' effect have been scant. Therefore, it remains unknown which factors are responsible for embryonic and early postnatal nutrition and which factors are major determinants of body weight and number of new born piglets. Intrauterine undernutrition, for example, was studied using a rat model providing dams 50% restricted nutrients during pregnancy and the results showed significant decreases in birth weight of newborns. This response may be a characteristic of a subset of modulations in embryonic development which is caused by the metabolic imprinting. Underlying mechanisms of intrauterine undernutrition and growth retardation can be explained in part by epigenetics. Epigenetics modulate animal phenotypes without changes in DNA sequences. Epigenetic modifications include DNA methylation, chromatin modification and small non-coding RNA-associated gene silencing. Precise mechanisms must be identified at the morphologic, cellular, and molecular levels by using interdisciplinary nutrigenomics approaches to increase pig production. Experimental approaches for explaining these potential mechanisms will be discussed in this review.

• Macromolecular Research
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• 제10권2호
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• pp.122-126
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• 2002

A molecularly imprinted polymer (MIP) having both amidine and imidazole functional groups in the active site has been prepared using p-nitrophenyl phosphate as a transition state analogue (TSA). The imprinted polymer MIP with amidine and imidazole found to have the highest hydrolysis activity compared with other MIPs with either amidine or imidazole groups only. It is postulated a cooperative effect between amidine and imidazole in the hydrolysis of p-nitrophenyl methyl carbonate (NPMC) as a substrate when both groups were arranged in proximity by molecular imprinting. The rate enhancement of the hydrolysis by MIP was 60 folds over the uncatalyzed solution reaction and two folds compared with the control non-imprinted polymer CPI having both functional groups. The enzyme-mimetic catalytic hydrolysis of p-nitrophenyl acetate by MIP was evaluated in buffer at pH 7.0 with $K_{m}$ of 1.06 mM and $k_{cat}$ of 0.137 $h^{-1}$ . . .

• Macromolecular Research
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• 제17권7호
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• pp.522-527
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• 2009

A photocrosslinkable polyphosphazene was used for molecular imprinting. We synthesized polyphosphazene (3) having urea groups for complexation with N-carbobenzyloxyglycin (Z-Gly-OH, template) and chalcone groups for cross-linking reaction. As substituents, 4-hydroxycha1cone (1) and N-(4-hydroxyphenyl)-N'-ethylurea (2) were prepared. Choloro groups of poly(dichlorophosphazene) were replaced by the sequential treatment with sodium salts of compounds 1 and 2, and trifluoroethanol. The template molecule was complexed with the urea groups on the polymer chains via hydrogen bonding. A thin polymer film was prepared by casting a solution of the complex of polymer 3 and the template in dimethylformamide on a quartz cell and irradiated with 365 nm UV light to yield a cross-linked film with a thickness of about $16{\mu}m$. The template molecules in the film were removed by Soxhlet extraction with methanol/acetic acid. The control polymer film was prepared in the same manner for the preparation of the imprinted polymer film, except that the template and triethylamine were omitted. In the rebinding test, the imprinted film exhibited much higher recognition ability for the template than the control polymer. We also investigated the specific recognition ability of the imprinted polymer for the template and its structural analogues. The rebinding tests were conducted using Z-Glu-OH, Z-Asp($O^tBu$)-OH, and Z-Glu-OMe. The imprinted film showed higher specific recognition ability for the template and the lowest response for Z-Asp($O^tBu$)-OH.

• 한국발생생물학회지:발생과생식
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• 제14권4호
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• pp.253-259
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• 2010

DNA 메틸화 (DNA methylation)는 유전자의 발현을 조절하는 대표적인 후생학적 조절기작 (epigenetic regulation) 중에 하나이다. DNA 메틸화 양상은 생식세포 형성과정 및 배 발생단계에서 탈메틸화 (demethylation)와 de novo 메틸화의 드라마틱한 변화가 일어난다. 또한 이러한 DNA 메틸화는 배아줄기세포 (embryonic stem cells, ESCs)에서 특징적인 양상을 보이는 것으로 알려져 있다. 본 연구에서는 생쥐 수정란 유래 배아줄기세포와 체세포핵이식 배아줄기세포 (nuclear transplanted ESCs)를 이용해서 대표적 각인유전자 (imprinting genes)로 알려진 Snrpn, Igf2r, H19 유전자들에 대한 메틸화 양상을 알아보고자 하였다. 연구 결과 H19 유전자에 대해서는 DNA 메틸화 양상은 수정란 유래 배아줄기세포와 체세포핵이식 배아줄기세포에서 비슷한 경향을 보였으나, Snrpn과 Igf2r의 경우에는 체세포핵이식 배아줄기세포에서 과메틸화 (hypermethylation) 경향을 보였다.

• KSBB Journal
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• 제20권3호
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• pp.133-141
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• 2005

This review presents the preparation, transport mechanism and application of molecularly imprinted membranes (MIM). Molecular imprinting has now been established as a technique which allows the creation of tailor-made binding sites for many classes of compounds. MIM have some advantages; a high capacity due to a large surface area, faster transport of substrate molecules and faster equilibrium of binding cavities compared to molecularly imprinted particles. MIM were prepared by covalent and non-covalent chemical bonding systems, by interactions between functional monomer and template. MIM can be prepared by in-situ polymerization, wet phase inversion, dry phase inversion, and surface imprinting method. MIM can continuously separate mixtures based on facilitated or retarded diffusion of the template. MIM can change their permeability in the presence of templates. MIM have a potential to be used to separate chiral compounds and materials with similar structures. However the application of MIM by the chemical industries is still in its infancy stages.

• KSBB Journal
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• 제16권2호
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• pp.115-122
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• 2001

Molecular imprinting has now been established as a technique which allows the creation of tailor-made binding sites for many classes of compounds. MIPs were prepared by covalent and non-covalent chemical bonding systems, by interactions between functional monomer and template. The shape of MIP is divided to particle and membrane. MIP membranes can be prepared by surface imprinting, in-situ polymerization, wet phase inversion and the dry phase inversion method. MIPs have been mainly used for analytical separation and biosensor systems to separate and detect chiral compounds and materials with similar structures. However the application of MIP by the chemical industries is still in its infancy stages. This review summarizes the preparative characteristics and applications of MIP with respect to chiral separations and biosensors.

• 생명과학회지
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• 제21권4호
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• pp.549-553
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• 2011

본 연구는 선행연구에서 molecular imprinting 방법을 이용하여 개발한 1-OHP 인식 $TiO_2$-Bead가 실제 소변중의 1-OHP를 효율적으로 검출할 수 있는지 평가하기 위해서 시행되었다. 본 연구에서 개발한 분석 방법은 within-day 변이계수가 4.97%, between-day 변이계수가 4.43%로 나타나 본 측정방법이 매우 안정적인 방법임을 확인할 수 있었다. 1-OHP와 유사한 물질들이 혼합된 용액으로부터 $TiO_2$-Bead-HPLC 측정방법의 회수율을 평가한 결과, 평균 105.6%의 회수율을 나타내었다. 실제 소변시료를 대상으로 기존의 효소-HPLC 측정방법과 본 측정방법 간의 상관성을 평가한 결과, 두 방법 간에는 높은 상관관계(r=0.74, p<0.01)를 보여 bead를 이용한 요중 1-OHP의 새로운 측정 방법의 유용성을 확인할 수 있었다. 본 연구에서 개발한 새로운 측정방법은 기존의 측정방법에 비해 요중 1-OHP 농도를 보다 간편하고 저렴한 가격으로 측정할 수 있다는 장점이 있다. 본 연구의 결과는 $TiO_2$ 코팅 bead를 응용한 요중 1-OHP 센서의 개발에 응용할 수 있을 것으로 생각되며, 분자주형을 이용한 bead의 개발은 1-OHP 이외의 다른 화학물질의 분석에도 다양하게 응용할 수 있을 것으로 기대된다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.337-342
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• 2007

In this study, molecular dynamics simulation of nano imprint lithography in which patterned stamp is pressed onto amorphous polyethylene(PE) surface are performed to study the behaviour of polymer. Force fields including bond, angle, torsion, and Lennard Jones potential are used to describe the inter-molecular and intra-molecular force of PE molecules and stamp, substrate. Periodic boundary condition is used in horizontal direction and canonical NVT ensemble is used to control the system temperature. As the simulation results, the behaviour of polymer is investigated during the imprinting process. The mechanism of polymer deformation is studied by means of inspecting the surface shape, volume, density, atom distribution. Deformation of the polymer resist was found for various of the stamp geometry and the alignment state of the polymer molecules.

• KSBB Journal
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• 제18권1호
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• pp.65-69
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• 2003

Pentoxifylline MIPs에서 시료와 기능성 단위체 사이에는 수소결합이 형성되었다. 수소결합의 능력은 분자구조상 질소원자의 위치에 의해 결정되어졌다. Pentoxifylline과 caffeine theophylline MIPs 모두는 구조상 유사한 시료들과 affinity가 증가하는 결과를 얻어냈다. 특히 caffiene-theophylline MIPs에서 높은 수치의 체류인자와 IF를 얻었다. 이러한 결과로 적합한 복합 주형분자를 사용할 때 우리가 원하는 목적시료만을 선택적으로 분리 할 수 있고 그러므로 solid phase extraction에 사용되기에 적합하다는 결과를 얻어냈다.

• 대한화학회지
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• 제48권1호
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• pp.7-11
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• 2004