• Kyungpook Mathematical Journal
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• 제56권3호
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• pp.939-949
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• 2016

In this paper, we give an algorithm to construct a space curve in Euclidean 3-space ${\mathbb{E}}^3$ from a plane curve which is called PDP-helix of order d. The notion of the PDP-helices is a generalization of a general helix and a slant helix in ${\mathbb{E}}^3$. It is naturally shown that the PDP-helix of order 1 and order 2 are the same as the general helix and the slant helix, respectively. We give a characterization of the PDP-helix of order d. Moreover, we study some geometric properties of that of order 3.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2000년도 International Symposium on Bioinformatics
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• pp.86-87
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• 2000

Protein folding is a fundamental problem in structural bioinformatics and so numerous studies have been devoted to the subject. As the most common regular secondary conformation in proteins, helix has been an important ingredient of the protein folding problem. In particular, alanine based polypeptides are widely studied to identify the helix folding process in that the aianine amino acid is known to have one of the highest helix propensities. In principle, intrinsic helix propensities can be obtained from gas-phase measurements where solvent effect is absent. Hudgins et al. studied alanine-based peptides in vacuo using high-resolution ion mobility measurement technique. It was reported that introduction of a single Iysine at the C terminus resulted in the formation of very stable, monomeric polyalanine helices. We also have investigated helix formation in vacuo with different terminal charge conditions; we have found a new type of helix motif, To the best of our knowledge, this type of helix conformation has not been characterized before and we name it as I-helix.

• 대한수학회논문집
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• 제20권4호
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• pp.861-873
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• 2005

In this paper we approximate a cylindrical helix by bi-conic and bi-quadratic Bezier curves. Each approximation method is $G^1$ end-points interpolation of the helix. We present a sharp upper bound of the Hausdorff distance between the helix and each approximation curve. We also show that the error bound has the approximation order three and monotone increases as the length of the helix increases. As an illustration we give some numerical examples.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.58-58
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• 2003

The envelope glycoprotein of HIV, gp41, mediates the membrane fusion with human cells. The extracellular domain of gp41 has two helical regions. The N-terminus helical region (N-helix) forms trimeric coiled coil, interacts with the C-terminus helical region (C-helix) of gp41 to form a stable helical bundle structure. In this study, we have shown that the N-helix of gp41 has membrane interacting and disrupting abilities. It was localized into the interface of the lipidic phase and head group of the membrane. In contrast, the N-helix region with membrane fusion defective mutations could not bind to membrane. In addition, the N-helix bound on the membrane was released from the membrane by the C-helix, and the complex of the N- and C-helix did not interact with membrane. These results suggested that the membrane binding ability of the N-helix is necessary for the fusion activity of gp41, and such property is possibly controlled by the C-helm.

• 한국임상수의학회지
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• 제37권1호
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• pp.42-45
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• 2020

Surgical ligation is the treatment of the choice in patients with patent ductus arteriosus (PDA). This case series presents two cases of PDA, one with and one without persistent left cranial vena cava (PLCVC), treated with surgical ligation through the descending aortic approach with mini-thoracotomy. There were no specific complications during the surgical procedures. The descending aortic approach would be an alternative method for dissection of the PDA.

• 한국경제지리학회지
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• 제13권3호
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• pp.335-353
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• 2010

지식기반경제의 도래와 함께 지역혁신을 분석하는 모형으로서 트리플 힐릭스에 대한 관심이 높아지고 있다. 트리플힐릭스 모형은 혁신과정에서 나타나는 산 학 관 네트워크를 삼중나선형의 움직임으로 파악한다. 트리플 힐릭스 혁신체제는 산 학 관의 관계적 구조에 따라 크게 3가지 거버넌스 형태를 가지고 있으며, 지식의 창출 및 이전 과정에서 나타나는 산 학 관의 경계중첩과 상호작용 특성에 따라 크게 3가지 발전단계를 나타낸다. 트리플 힐릭스 모형은 국가 및 지역 혁신체제론과 이론적 연계성이 큼에도 불구하고 혁신체제의 불완전성, 지식창출 메커니즘, 대학의 역할 등에 대해 상대적으로 크게 강조하고 있다는 점에서 차별성이 있다. 트리플 힐릭스는 주로 지역 단위에서 구현되는데, 이를 위해서는 지식공간, 합의공간, 혁신공간으로 구성된 3층위의 트리플 힐릭스 공간체계가 형성되고 개별적인 트리플 힐릭스 공간들이 상호작용하는 체계가 형성될 때 비로소 지역혁신이 효과적으로 일어날 수 있다. 연구방법 측면에서 트리플 힐릭스 모형을 적용한 기존의 연구들은 주로 양적 연구방법과 질적 연구방법을 선택적으로 활용하고 있으나, 향후에는 두 가지 연구방법을 적절하게 연계하여 각 연구방법의 한계를 보완하여 진행될 필요성이 있다.

• 대한화학회지
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• 제31권5호
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• pp.471-475
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• 1987

수용액에서 Fe(II)-poly(D-glutamic acid) (PGA) 복합물 형성이 pH와 농도에 따라서 흡수와 원이색성 분광 광도계로 확인되었으며, 철 이온과 복합물 형성에 의한 PGA의 구조 변화와 안정도 상수도 검토되었다. PGA와 Fe(II)사이에 형성된 후 pH4.3에서는 ${\alpha}$-helix를 파괴(${\alpha}$-helix 파괴 효과)하고 pH5.7에서는 ${\alpha}$-helix를 유도(${\alpha}$-helix유도 효과)하는 것을 알 수 있었다. ${\alpha}$-helix의 PGA구조가 random coil의 PGA구조 보다 전 안정도 상수 값이 큰 것으로 보아 random coil의 PGA구조에서 더욱 안정된 복합물을 형성하고 있음을 알 수 있었다.

• Biomolecules & Therapeutics
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• 제27권6호
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• pp.514-521
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• 2019

G protein-coupled receptors (GPCRs) are membrane receptors whose agonist-induced dynamic conformational changes trigger heterotrimeric G protein activation, followed by GRK-mediated phosphorylation and arrestin-mediated desensitization. Cytosolic regions of GPCRs have been studied extensively because they are direct contact sites with G proteins, GRKs, and arrestins. Among various cytosolic regions, the role of helix 8 is least understood, although a few studies have suggested that it is involved in G protein activation, receptor localization, and/or internalization. In the present study, we investigated the role of helix 8 in dopamine receptor signaling focusing on dopamine D1 receptor (D1R) and dopamine D2 receptor (D2R). D1R couples exclusively to Gs, whereas D2R couples exclusively to Gi. Bioinformatic analysis implied that the sequences of helix 8 may affect GPCR-G protein coupling selectivity; therefore, we evaluated if swapping helix 8 between D1R and D2R changed G protein selectivity. Our results suggest that helix 8 is not involved in D1R-Gs or D2R-Gi coupling selectivity. Instead, we observed that D1R with D2R helix 8 or D1R with an increased number of hydrophobic residues in helix 8 relative to wild-type showed diminished ${\beta}$-arrestin-mediated desensitization, resulting in increased Gs signaling.

• 한국기계가공학회지
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• 제1권1호
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• pp.15-22
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• 2002

This study shows how the change of helix angle of different helix angle end mill affects machining accurracy. It was verified that cutting force are remarkably low when endmill has helix angle of different helix angle 250, 310, 370 and AE signal have less reationshap with the change of helix angle. Moreover, as the number of rotations are increases, the AE signal increased with the proportion to the number but cutting force are inversely proportional to the rotation.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.239-244
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• 2002

This study shows how the change of helix angle for different helix angle end mill affects machining accuracy. It was verified that cutting forces are remarkably low when endmill has helix angle of different helix angle $25^{\circ}\;, \; 31^{\circ}\; , \; 37^{\circ}$and AE signals have less relationship with the chance of helix angle Moreover, as the number of rotations are increased, the AE signals are increased with the proportion to the number but cutting forces are inversely proportional to the rotation.