• 한국정밀공학회지
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• 제18권7호
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• pp.143-148
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• 2001

In this study, a mechanistic model of cutting force components in up and down end milling process is presented. Using this cutting force model of 4-tooth endmills with various helix angles, cutting force variation of inconel 718 has been predicted. Predicted values of cutting force components are coincide well with the measured ones. As helix angle increases, overlapping effects of the active cutting edges increase. In up endmilling the magnitudes of radial and feed cutting force componts FX and FY are lowest when the helix angle is $40\{\circ}$, but in down endmilling the magnitudes of these values increase slightly as helix angle becomes large.

• 한국임상수의학회지
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• 제35권2호
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• pp.63-66
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• 2018

A 5-month-old castrated male Bichon $Fris{\acute{e}}$ was presented with a subcutaneous mass on the occipital region. Anisocytosis, anisokaryosis, and binucleation were observed on the cytology, and the suspected diagnosis was sarcoma. There were no metastatic lesions on radiography or computed tomography. Surgical resection was performed and fibrosarcoma was diagnosed by histopathology and immunohistochemistry. This is a very rare case of a spontaneously occurring subcutaneous fibrosarcoma in a small breed puppy.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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• pp.25-27
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• 2010

Helical steel piles are being widely used in foundation for the buildings in urban areas because of their high compressive and tensile capacities. Helical steel piles have many advantages; ease installation, a vibration-free and low level of noise process, and so on. However, the most researches are about the capacity of helical steel piles under uplift condition. Therefore, this paper focuses on the capacity under compressive loading according to the soil condition. The bearing capacity of helical steel piles varies with the diameter of the helix and shaft and the bearing area of helical steel piles is not always identical with the sum of helix and shaft area due to the difference of each bearing mechanism. Therefore, the experiment with the parameters of the ratio of helix and shaft diameter and soil condition will be carried out to survey the effective helix area under a given soil condition for the bearing capacity of helical steel piles.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3627-3631
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• 2014

In this study we examined two ester-containing cross-links, hex-2-enyl acetate and hex-2-enyl propionate, as new cross-linking systems for helix stabilization of short peptides. We demonstrated that these hexenyl ester cross-links can be readily installed via a ruthenium-mediated ring-closing metathesis reaction of L-aspartic acid 4-allyl ester or L-glutamic acid 5-allyl ester at position i and (S)-2-(4'-pentenyl)alanine at position i+4 using second generation Hoveyda-Grubbs catalyst at $60^{\circ}C$. Between these two cross-links, we found that the hex-2-enyl propionate significantly stabilizes the ${\alpha}$-helical conformations of short model peptides. The helix-stabilizing effects of the hex-2-enyl propionate tether appear to be as powerful as Verdine's i,i+4 all-hydrocarbon stapling system, which is one of the most widely used and the most potent helix-stabilizing cross-linking systems. Furthermore, the hex-2-enyl propionate bridge is reasonably robust against non-enzymatic hydrolytic cleavage at a physiological pH. While extended studies for probing its chemical scopes and biological applications are needed, we believe that this new helix-stabilizing system could serve as a useful chemical tool for understanding protein folding and designing conformationally-constrained peptide drugs.

• Journal of Applied Biological Chemistry
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• 제55권1호
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• pp.67-70
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• 2012

Plant MYB transcription factors regulate secondary metabolism, cellular morphogenesis, and plant hormone signaling pathway. MYB proteins in plants consist of two repeats of 50 amino acid residues, which are referred to as R2R3 and they interact with WD40 or basic helix loop helix (bHLH) proteins. Yeast two hybrid assay was determined whether rice MYB protein interacts with either OsTTG1, which contains a WD40 domain, or with OsGL3, which contains a bHLH domain. Among 30 OsMYB proteins, three interacted with OsTTG1 and five interacted with OsGL3. A series of MYB mutants were created to determine the MYB domain important for the interaction with OsTTG1 or OsGL3. By using the yeast two hybrid assay, we found that the R3 motif of OsMYB10 and the R2 motif of OsMYB16 were required for interaction with OsTTG1 and OsGL3 proteins, respectively.

• EDISON SW 활용 경진대회 논문집
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• 제5회(2016년)
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• pp.62-66
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• 2016

Tumor suppressor protein p53 loses its function upon binding with the HDM2 protein, and inhibiting the p53-HDM2 interaction is critical to suppress tumor cell growth. Recently, the cyclized helix-loop-helix peptide (cHLH) mimicking the ${\alpha}-helix$ part of the p53 protein has been designed and found to exhibit high binding affinity with HDM2. Here, we report the structural and thermodynamic characteristics of the bound complex of the cHLH peptide with the HDM2 protein. We performed molecular dynamics simulations to investigate the structural features of the cHLH peptide as well as its complex with the HDM2. The binding free energy calculation based on the integral equation theory was also executed to quantify the binding affinity for the cHLH/HDM2 complex and to understand the factors contributing to the binding affinity. We found a variety of factors for the helix stability of the cHLH peptide as well as in the complexation with the HDM2, which may provide an insight into the development of anti-cancer drug designs.

• Design & Manufacturing
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• 제17권1호
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• pp.33-39
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• 2023

The ball end mill is a type of cutting tool that is widely used to process complex mold shapes including aspheric surfaces. Unlike the flat end mill in which the cutting edge is formed on the cylindrical handle, the cutting edge is formed from the cylindrical handle to the hemispherical shape, which is advantageous for processing curved shapes. However, since the cutting speed continuously changes during machining due to the helix angle of the cutting edge or the machining inclination angle, it is difficult to obtain a precise machined surface. Therefore, in this paper, machining was performed while changing the helix angle of the ball end mill and the angle of the machining slope under the same cutting conditions for STD 11 material, which is widely used as a mold material. Through this, the effect of the two variables on the roughness of the machined surface was analyzed. As a result, if the helix angle was 0 degrees, it showed the best surface roughness of Ra. 0.16 ㎛. When the helix angle was 20 degrees, the best surface roughness of Ra. 0.18 ㎛ was occurred.

• 한국경제지리학회지
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• 제17권1호
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• pp.69-85
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• 2014

본 연구의 목적은 두 종류의 서로 다른 트리플 헬릭스 모델(대학주도형 vs. 제3섹터형)이 기업혁신에 미치는 영향을 밝히는 데 있다. 특히 사회적 자본으로서의 신뢰가 두 종류의 트리플 헬릭스 상호작용과 기업혁신 사이의 관계에 있어 조절효과를 보이는 지에 주안점을 두고 있다. 우리나라에서는 정부부처(교과부 vs. 지식경제부: <교육부 vs. 미래창조과학부>)를 중심으로 크게 두 가지 방식의 트리플 헬릭스 상호작용이 진행되어 왔다. 하나는 기업가적 대학이 중심적인 역할을 하는 대학주도형 전통적인 트리플 헬릭스 상호작용이며, 또 다른 하나는 테크노파크와 같은 제3섹터형 기관이 트리플 헬릭스 상호작용을 수행하는 제3섹터 주도형 방식이다. 본 연구는 대구 경북 지역에 위치한 231개 기업으로부터 수집한 자료를 바탕으로 하고 있다. 분석 결과, 첫째 제3섹터형 기관의 지원을 통한 트리플 헬릭스 상호작용은 기업혁신에 정(+)의 영향을 미치는 것으로 나타났다. 반면 대학주도형 트리플 헬릭스 상호작용은 기업혁신에 유의미한 영향을 미치지 못했다. 둘째, 제3섹터형 기관의 지원은 전통적인 트리플 헬릭스 상호작용보다 기업혁신에 더 큰 정(+)의 영향을 미치는 것으로 나타났다. 셋째, 신뢰는 두 종류의 트리플 헬릭스 상호작용에 있어서 기업혁신에 대한 정(+)의 조절효과를 보여주었다. 결론에서는 연구의 시사점과 연구의 한계점, 향후 연구방향 등이 제시되었다.

• 한국자기공명학회논문지
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• 제19권2호
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• pp.61-66
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• 2015

The plant hormone auxin is involved in all stages of plant development. Aux/IAAs are the transcriptional repressors that bind to the Auxin Response Factors (ARFs) to regulate the gene expression upon auxin release. Aux/IAA have highly conserved C-terminal domains (domains III-IV) that mediate both homotypic and heterotypic interactions between Aux/IAA and ARF family proteins. Recent studies revealed that the conserved domains III-IV share a common ${\beta}$-grasp fold that oligomerizes in a front-to-back manner. In particular, Aux/IAA contains a mobile insert helix in the domain III-IV, whereas ARFs do not. Here, we investigated the dynamics of the insert helix using paramagnetic NMR spectroscopy. The insert helix exhibited fast motions in the ps-ns time scale from $^{15}N$ relaxation data, but the amplitude of the motion is likely limited to the local neighborhood. Our result suggests that the motion of the helix may have functional implications in protein-protein interactions for transcriptional regulations.

• Molecules and Cells
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• 제42권10호
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• pp.729-738
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• 2019

Autophagy is an important process for protein recycling. Oligomerization of p62/SQSTM1 is an essential step in this process and is achieved in two steps. Phox and Bem1p (PB1) domains can oligomerize through both basic and acidic surfaces in each molecule. The ZZ-type zinc finger (ZZ) domain binds to target proteins and promotes higher-oligomerization of p62. This mechanism is an important step in routing target proteins to the autophagosome. Here, we determined the crystal structure of the PB1 homo-dimer and modeled the p62 PB1 oligomers. These oligomer models were represented by a cylindrical helix and were compared with the previously determined electron microscopic map of a PB1 oligomer. To accurately compare, we mathematically calculated the lead length and radius of the helical oligomers. Our PB1 oligomer model fits the electron microscopy map and is both bendable and stretchable as a flexible helical filament.