• Kyungpook Mathematical Journal
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• v.56 no.3
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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.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2000.11a
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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.

• Communications of the Korean Mathematical Society
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• v.20 no.4
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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.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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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.

• Journal of Veterinary Clinics
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• v.37 no.1
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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.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.3
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• pp.335-353
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• 2010

Following the emergence of a knowledge-based economy, the triple helix model has been recognized as a new - regional and national - innovation model. This model seeks to understand the innovation process that is centered upon the university-industry-government interactions. The governance of the triple helix innovation system can be divided into three models according to the structure and depth of university-industry-government interactions. In the context of evolution, the triple helix can be established through the following three processes of development; i) internal transformation of each helix, ii) impacts of one helix on another helix, and iii) horizontal interactions among three helices. In theory, the triple helix model can be covered as part of the innovation system perspective. Compared to the innovation system perspective, the triple helix model tends to pay, however, more attention to the incompleteness of innovation system and the role of university in the process of knowledge creation. In view of regional innovation, the triple helix can be sustained when the triple helix spaces, including knowledge space, consensus space and innovation space, are created and the three triple helix spaces interact with one another. The existing literature on the triple helix model tends to make selectively use of only a single method between the qualitative method and the quantitative method, although both have shortcomings to reveal the dynamic characteristics of university-industry-government relations. Therefore, research on the triple helix is required to reconcile with two research methods, which are distinct but complementary in nature.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.471-475
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• 1987

Fe(II)-poly(D-glutamic acid) (PGA) complex in aqueous solution has been investigated as functions of pH and concentration of Fe(II) by using absorption and circular dichroism spectroscopies. The helix-breaking interaction occurred at pH 4.3 while the helix-directing one occurred at pH 5.7 after forming complex between PGA and Fe(II). The relationship between conformation change of PGA by forming complex with Fe(II) and complex constants for the above system was studied. As a result, stability constants in random coil structure of PGA are larger than those in ${\alpha}$-helix structure. This result indicates that the random coil structure of PGA-Fe(II) complex shows more stable complex than ${\alpha}$-helix one.

• Biomolecules & Therapeutics
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• v.27 no.6
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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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.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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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.