• Polymer(Korea)
• /
• 제37권5호
• /
• pp.625-631
• /
• 2013

Mucoadhesive property is the major function as an adhesive for medical devices, and therefore, these days many researches have conducted to develop polymers having this property. Recently, biomimetic technology has been used for developing mucoadhesive polymers. Among many technologies, mussel-inspired approaches have received noticeable attention because of its thread's strong adhesive characteristics. In this study, we synthesized mucoadhesive biomimetic polymers employing catechol structures which are abundant in mussel adhesive proteins, and their structures and molecular weights were characterized by using nuclear magnetic resonance spectroscopy and gel permeation chromatography. To evaluate in vitro mucoadhesive strength, the sheet type of the small intestinal porcine submucosa was prepared. Compared to commercial fibrin glue adhesives, catechol-containing mucoadhesive polymers showed enhanced adhesive strength. The study of adhesive strength with considering diverse factors, such as temperature, pressure, and oxidant amount indicated that mussel-inspired mucoadhesive polymer could be a promising candidate for an adhesive in various biomedical applications.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• 제18권7호
• /
• pp.1619-1627
• /
• 2014

Wearable computer systems can use the wireless universal serial bus (WUSB) that refers to USB technology that is merged with WiMedia PHY/MAC technical specifications. In this paper, we focus on an integrated system of the wireless USB over the IEEE 802.15.6 wireless body area networks (WBAN) for wireless wearable computer systems supporting U-health services. And a communication structure that performs the time-synchronization is proposed for WUSB over IEEE 802.15.6 hierarchical protocol. Proposed time-synchronization mechanisms adopt the WBAN Polling Access and combine it with a time-synchronization middleware using time stamps. In our performance evaluations, time-synchronization performances with only WBAN Polling Access scheme are analyzed first. After that, performances combined with the time-synchronization middleware are analyzed to evaluate the effectiveness of proposed time-synchronization structure in WUSB over IEEE 802.15.6.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• 제33권6호
• /
• pp.276-281
• /
• 2023

With the high design freedom of the additive manufacturing process, there is a growing interest in multi-dimensional lattice structures among researchers, who are studying intricate structural modeling that is challenging to produce using conventional manufacturing processes. In the case of titanium alloy implants for human insertion, a multi-dimensional lattice structure is employed to ensure compatibility with bones, adjusting strength and elastic modulus to levels similar to those of bones. Therefore, securing a database on the mechanical properties based on lattice structure design variables and the development of related simulation techniques are believed to efficiently facilitate the customization of implants. In this study, lattice structures were additively manufactured using Ti-6Al-4V alloy, and the elastic modulus was measured based on design parameters. The results were compared with simulations, and an approach to finite element analysis for accurate prediction of the elastic modulus was proposed.

• Journal of the Korean Society of Food Science and Nutrition
• /
• 제41권3호
• /
• pp.310-319
• /
• 2012

In order to investigate the biological effects of conformational changes in the folding state of bovine ${\alpha}$-lactalbumin (${\alpha}$-La), the protein was prepared and classified as apo form, microbial transglutaminase (MTGase) added form, or bovine ${\alpha}$-La made lethal to tumor cell (BAMLET) form. Apo ${\alpha}$-La form showed weaker cancer cell inhibitory activity (apoptosis) than native ${\alpha}$-La, which suggests that the metal ion-like $Ca^{2+}$ had a positive effect, whereas BAMLET form showed strong cancer cell apoptotic activity. The BAMLET form seemed to be a molten globule structure that increased hydrophobicity. MTGase added to apo ${\alpha}$-La polymer showed similar anti-cancer activity as native ${\alpha}$-La, and it was well hydrolyzed by digestive enzymes. NMR results showed that BAMLET interacted with oleic acid and produced a complex.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• 제36권12호
• /
• pp.1497-1502
• /
• 2012

To manufacture a robot hand that essentially mimics the functions of a human hand, it is necessary to develop flexible actuators and sensors. In this study, we propose the design, manufacture, and performance verification of flexible actuators and sensors based on Electro Active Polymer (EAP). EAP is fabricated as a type of film, and it moves with changes in the voltage because of contraction and expansion in the polymer film. Furthermore, if a force is applied to an EAP film, its thickness and effective area change, and therefore, the capacitance also changes. By using this mechanism, we produce capacitive actuators and sensors. In this study, we propose an EAP-based capacitive sensor and evaluate its use as a robot hand sensor.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 한국의학물리학회 2003년도 제27회 추계학술대회
• /
• pp.48-48
• /
• 2003

Abstract: 현대 질병의 최종진단은 세포수준의 해부형태학적 연구가 일반적이며 광학현미경이나 전자현미경을 이용한 병리조직학적 소견을 바탕으로 진단되어지고 있다. 이러한 진단에는 In vivo 검사가 거의 불가능하여 주로 생검을 통한 연구만 수행되고 있어 진단함에 있어 단계적인 불편이 초래될 뿐만 아니라 악성 종양의 전이를 유발시킬 수 있고 또한 생리 및 생화학적 분석이 어렵다. 이러한 문제점을 해결하기 위해 고분해능의 RF Surface Coil을 개발하여 In vivo 및 비침습적인 방법인 MR Technology를 이용하고자 한다. Introduction: 피부조직과 같은 미세 인체구조 연구를 위해 고해상도 3T MRI 시스템에 적합한 고분해능의 RF surface coil을 개발하고 있다. In vivo 연구를 위한 여러 parameter를 최적화하여 기능영상에도 부합된다. 비침습적인 In vivo 검사에 의한 세포수준의 극 미세구조의 연구가 가능해짐으로써 과거 시행하던 침습적인 생검없이 각종질환의 진단적 접근이 병리학적 수준으로 향상되어 질병의 정확한 진단이 가능해지게 될 것이다. Method: 고분해능의 RF Surface Coil을 제작하여 3T MR 장비에서 피부 미세구조연구에 보다 적합하도록 In vivo 및 In vitro 실험을 수행하였다. In vitro 실험은 In vivo 연구를 위한 여러 parameter들을 최적화하기 위한 기초 실험을 하였고 다양한 팬톰들을 이용하여 Tl 강조영상, T2 강조영상을 획득하였으며, SNR을 높이기 위한 개선에 대한 연구를 수행하였다. In vivo 실험은 정상피부에서 다양한 부위에 대한 피부영상의 예비 연구를 수행하였다. Result and Discussion: 비침습적인 In vivo 검사에 의한 세포수준의 극 미세구조의 연구가 가능해짐으로써 과거 시행하던 침습적인 생검없이 각종질환의 진단적 접근이 병리학적 수준에서 가능해짐으로써 질병의 정확한 진단이 가능해지게 될 것이다. Acknowledgement: 본 연구는 2002 년도 한국과학재단 목적기초연구사업 (과제번호 : R0l-2002-000-00294-0 (2002)) 지원아래 수행되었다.

• Journal of the Korea Concrete Institute
• /
• 제26권4호
• /
• pp.465-474
• /
• 2014

This is a comparative study that shows the overall environmental impacts from concrete structures when different compressive strength of concrete applied to structural systems having the same reference flow with different durability. A total of 24 MPa, 40 MPa and 60 MPa cases is analyzed to define the characteristic using end-point perspective LCA methodology including the stages of production, construction, maintenance and disposal. As results, global warming, non-renewable energy and respiratory inorganics problems are the major issues for assessing environmental impacts of concrete products.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• 제50권2호
• /
• pp.119-129
• /
• 2024

The cutaneous lymphatic system in humans plays a crucial role in draining interstitial fluid and activating the immune system. Environmental factors, such as ultraviolet light and natural aging, often affect structural changes of such lymphatic vessels, causing skin dysfunction. However, some limitations still exist because of no alternatives to animal testing. To better understand the skin lymphatic system, a biomimetic microfluidic platform, skin-lymph-on-a-chip, was fabricated to develop a novel in vitro skin lymphatic model of humans and to investigate the molecular and physiological changes involved in lymphangiogenesis, the formation of lymphatic vessels. Briefly, the platform involved co-culturing differentiated primary normal human epidermal keratinocytes (NHEKs) and dermal lymphatic endothelial cells (HDLECs) in vitro. Based on our system, Lymphanax^TM, which is a condensed Panax ginseng root extract obtained through thermal conversion for 21 days, was applied to evaluate the lymphangiogenic effect, and the changes in molecular factors were analyzed using a deep-learning-based algorithm. Lymphanax^TM promoted healthy lymphangiogenesis in skin-lymphon-a-chip and indirectly affected HDELCs as its components rarely penetrated differentiated NHEKs in the chip. Overall, this study provides a new perspective on Lymphanax^TM and its effects using an innovative in vitro system.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• 제2권
• /
• pp.139-182
• /
• 1994

조종사들은 비행시에 일상 생활 환경에서는 경험하지 못하는 여러가지 적대환경에 폭로된다. 이러한 환경에서는 인체의 평형기관은 실제와 일치하지 않는 정보를 제공해 주는 경우가 허다하다. 예를들면, 내이의 미로 전정기관이나 피하압력기관기 등은 항공기의 기동으로 발생하는 중력과 지구의 중력을 구별 하지 못하는 기능의 한계성때문에 계기비행하에서는 대개의 경우 공간정위상실, 즉 비행착각을 유발한다. 이 착각으로 인한 항공기 사고는 통계상에서 상당 부분이 치명사고로 나타나고 있는데, 이러한 사실은 비행착각현상이 비행안전에 극히 위험한 요소가 되고 있다는 것을 실증한다고 할 수 있다. 그러므로 조종사들은 비행시 공간정위 유지를 위한 철저한 대비가 있어야 한다. 공간정위 상실현상이 잘 발생하는 경우는 야간이나 기타 계기비행 환경에서 주위시각이 제약을 받을 때이다. 즉, 계기비행 환경에서의 편대비행시나 고기동시, 그리고 대조물이 모호한 야간의 활주로에서 이착륙할때 등을 들 수 있다. 비행시 공간정위 상실현상을 예방하기 위해서는 첫째로 이러한 유형의 사고분석자료를 토대로 하여 항공기의 설계단계에서부터 제작에 이르기까지 착각을 유발할 수 있는 구조적 요인을 제거해야 한다. 둘째로는 이러한 착각을 유발하지 않는 운항이나 기동방식을 택하여 비행임무를 수행토록 해야한다. 세째로 조종사들은 이러한 착각을 정상적인 인체의 반응에 의한 것이므로 자신에게도 당연히 일어난다는 사실을 용인해야 한다. 네째로 조종사들은 계기비행에 대한 구체적이고 실제적인 훈련을 통하여 계기비행 경험을 쌓아야 한다. 다음은 조종사들의 실제비행시 공간정위 상실현상에 봉착했을때의 처리요령이다. 첫째로 계기비행상황에서 자신의 감각과 계기가 일치하지 않을 때는 즉시 계기를 Cross Check하여 항공기의 자세나 기동형태를 정확하게 파악해야 한다. 둘째로 계기가 조종사의 의도대로 나타나도록 조작하고 이를 철저하게 의지하고 믿어야 한다. 세째로 자신의 감각과 계기가 일치할때까지 수평비행을 유지해야 한다. 그리고 마지막으로, 고성능 항공기가 계기비행중 저공에서 비행착각에 봉착하게 될때의 행동절차를 철저하게 숙지하고 있어야 한다.

• Journal of Mushroom
• /
• 제19권3호
• /
• pp.115-125
• /
• 2021

Mushroom consumption causes changes in the immune system and gut microbiota via the actions of mushroom probiotic components. β-Glucan structure-related substances suppress secretion of inflammatory mediators, and induce macrophage activation, enhancing immunity and immune function. Substances other than directly useful components can be metabolized into short-chain fatty acids by gut microbiota. These short-chain fatty acids can then induce immunity, alleviating various diseases. Substances used to stimulate growth of health-promoting gut bacteria, thereby changing the gut microbiota community are defined to be probiotics. Probiotic altered intestinal microflora can prevent various types of bacterial infection from external sources, and can help to maintain immune system balance, thus preventing diseases. Research into beneficial components of Pleurotus eryngii, Lentinula edodes, Pleurotus ostreatus, Flammulina velutipes, Auricularia auricula-judae, and Agaricus bisporus, which are frequently consumed in Korea, changes in microbiota, changes in short-chain fatty acids, and correlations between consumption and health contribute to our understanding of the effects of dietary mushrooms on disease prevention and mitigation.