• 대한의용생체공학회:의공학회지
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• 제38권2호
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• pp.57-61
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• 2017

The purpose of this study was to investigate the effect of direction (pitch and roll) on the perception of support surface rotation while standing. Thirty young healthy subjects participated in this study. Support surface was rotated at an unexpected instant in a very slow speed (0.2 deg/s). The direction of support surface rotation was randomly chosen among pitch (forward and backward) and roll (right and left) directions. The experiment was performed with eyes open and closed. Perception performance was evaluated by the perception threshold, defined as the rotation angle of the surface at the instant when a subject recognized that the support surface was moving. Results showed that the perception threshold was smaller for roll directions than pitch directions irrespective of vision and gender (p < 0.01). This indicates that the perception of support surface rotation is more sensitive in roll direction than in pitch direction. Among three sensory functions related to postural perception, the effect of vestibular and visual functions on the direction difference of the perception should be little because of the very slow surface rotation and independence on visual conditions. Therefore, the direction dependence of perception would have been affected mainly by the somatosensory function.

• 한국어류학회지
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• 제24권4호
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• pp.247-252
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• 2012

한국산 송사리속 2종에 대한 섭이기관의 구조적 차이를 알아보기 위하여 악골 및 이빨 구조를 조사하였다. 악골에서 송사리 Oryzias latipes는 전상악골 중앙부의 등 쪽 가장자리에 움푹 들어가는 홈이 존재하였으나 대륙송사리 O. sinensis는 일직선이었다. 후반부의 위치에서 송사리는 중앙부와 일직선상에 존재하였으나 대륙송사리는 배 쪽에 존재하였다. 또한 송사리는 하악골의 구상돌기 아래로 이어지는 치골 뒷가장자리에 움푹 들어가는 홈이 존재한 반면에 대륙 송사리에서는 뒷가장자리가 일직선 모양을 하였다. 송사리는 성적이형으로서 수컷에서만 나타나는 큰 이빨이 하악골의 측면 방향으로 발달하였고, 대륙송사리는 등 쪽 방향으로 발달하였다. 한편 송사리의 이빨형태는 원뿔모양과 화살촉모양 2 types이 나타난 반면에 대륙송사리에서는 원뿔 모양 1 type만 나타나는 특징을 보였다. 이상과 같이 한국에 분포하는 2종의 송사리는 섭이기관에서 뚜렷한 종간의 특징을 잘 보여 주었다.

• ALGAE
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• 제30권2호
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• pp.89-101
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• 2015

Ecklonia cava Kjellman is a common kelp found in shallow subtidal in warm-temperate waters in the northwest Pacific Ocean. This species has shown substantial morphological variation along with subsistence in different locations and local environments. We quantified the magnitude of morphological variation of E. cava from six populations along ~700 km of coastline from Jeju Island to Dokdo in Korea. In addition, we examined genetic distance among the populations using random amplified polymorphic DNA (RAPD) analysis. Most morphological characteristics investigated were significantly different among locations. Multivariate analyses indicated two phenetically distinct groups (nearshore, sheltered vs. offshore, exposed), indicating wave exposure with turbidity are presumably major factors for the separation. With RAPD data, results of Nei's diversity (H) and AMOVA showed considerable variations in within- and between-populations. Pairwise ${\Phi}_{ST}$ and $N_m$ values indicated moderate gene flow between the six locations. Results of Nei's analysis revealed three genetically distinct groups, not consistent with the morphological groupings, indicating that a time gap may exist between morphological and genetic variations. This study also suggests dispersal distance of this kelp may be longer than what is commonly thought and genetic similarity in the populations was largely reflected by the direction of ocean current rather than just geographical distance.

• Journal of Korean Biological Nursing Science
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• 제19권4호
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• pp.227-240
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• 2017

Purpose: The purpose of this review was to identify the current status of nursing studies on heart failure (HF) patients in South Korea and to suggest future study direction. Methods: A literature review of databases such as KoreaMed, KERIS and nursing and allied health journal were searched with key terms 'heart failure' and 'nursing' for the period from January 2000 to February 2017. A total of 35 studies including 28 articles and 7 theses met the inclusion criteria. Results: Twenty-seven out of 35 studies were observational studies on outpatients and most of the studies did not mention the ejection fraction and New York Heart Association functional classification class (NYHA class) in the inclusion criteria. Self-care and health-related quality of life as psychological factors, and physical activity as a biological factor, were used as main variables. However, we found it difficult to understand how much score indicates better quality of life because of an inconsistent and wide score. In quality assessment, 8 intervention studies had no serious flaws. Conclusion: Further studies should consider more biological and social factors influencing HF. The quality assessment with respect to nursing intervention studies in HF showed that randomized and double-blind trials are needed.

• Reproductive and Developmental Biology
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• 제38권1호
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• pp.9-19
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• 2014

For successful embryo implantation, the communication of the maternal endometrium with the conceptus trophectoderm is required essentially. In pigs, conceptuses undergo morphological change in length to enlarge the physical contact area with the maternal endometrium and secrete estrogen to induce the maternal recognition of pregnancy during the peri-implantation period. Conceptus-derived estrogen prevents luteolysis by conversion in direction of $PGF_{2{\alpha}}$ secretion from the uterine vasculature to the uterine lumen as well as it affects on expression of the uterine endometrial genes. In addition to estrogen, conceptuses release various signaling molecules, including cytokines, growth factors, and proteases, and, in response to these signaling molecules, the maternal uterine endometrium also synthesizes many signaling molecules, including hormones, cytokines, growth factors, lipid molecules, and utilizes ions such as calcium ion by calcium regulatory molecules. These reciprocal interactions of the conceptus trophectoderm with the maternal uterine endometrium make development and successful implantation of embryos possible. Thus, signaling molecules at the maternal-conceptus interface may play an important role in the implantation process. This review summarized syntheses and functions of signaling molecules at the maternal-conceptus interface to further understand mechanisms of the embryo implantation process in pigs.

• 대한의용생체공학회:의공학회지
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• 제16권3호
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• pp.289-300
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• 1995

지금까지는 혈관의 중심선을 구해서 혈관의 직경을 측정해 왔다. 혈관의 중심선을 구하는 방법은 2가지가 보고되어 있는데 그중 하나는 maunal로 중심선을 찾는 observer-defined 방법이다. 이 방법을 사용자에 따라 변화할 가능성이 잠재한다, 또 다른 방법은 자동으로 혈관의 중심을 찾아내는 것인데 대단히 복잡하다. 이 논문에서, 중심선을 찾지 않고 방향코드와 위치정보를 이용하여 직경을 구하는 새로운 방법을 제안한다. 이 방법은 경계선과 방향코드를 동시에 검출하기 때문에 절차가 간단해지고 처리속도도 빨라진다. 중앙선을 이용하여 자동으로 혈관직경을 구하는 방법과 비교해보면, 가지가 있거나 장애가 있는 혈관 이미지에 있어서 정확도가 개선된다. 또한 방향 코드는 3비트로 코드화되기 때문에 혈관정보를 압축 저장하는데 용이하다. 이 방법은 실험을 통하여 유용성이 있음을 확인하였다.

• 대한의용생체공학회:의공학회지
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• 제18권3호
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• pp.253-259
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• 1997

Von Mises stress and compliance distribution was evaluated using a finite element analysis on the anastomosis of an artery with length of 20mm(z direction, along the horizental artery), inner diameter of 4mm, thickness fo 0.5mm and a PTFE graft with length of 5.7mm, inner diameter of 2mm, thickness of 0.2mm when anastomotic angle was $45^{\circ}$ and inner pressure of 1330 dyne/mm2 was applied inside the 2 conduits. From the analysis results were obtained as follows. (1) Artery diameter increased in both horizontal x(along the length of artery) and vertical y(perpendicular to the length of artery)directions and the magnitude of that in x direction was bigger than that in y direction. (2) The compliance was maximum on the anastomosis, especially on that with acute angle. The reduction of compliance was observed from the anastomosis area to the either right or left end. (3) The equivalent stress was maximum on top in the y direction and minimum on the nodes apart $110^{\circ}$ in circumferential direction from the top. (4) The equivalent stress was maximum in t도 vicinity of anastomosis with acute angle along the longitudinal direction of the artery. This trend was also observed along the PTFE graft.

• Journal of Applied Biological Chemistry
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• 제58권2호
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• pp.157-174
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• 2015

토양 중금속 안정화를 위해 농축수산 부산물, 산업부산물 등과 같은 다양한 폐자원이 활용되고 있다. 일례로 석회, 패각류, 난각류, 산업부산물 등의 알칼리물질, 동물의 뼈 및 인산용액, 인광석 등의 인 함유물질, 퇴비(compost), 가축분(manure), 바이오차(biochar) 등의 유기성물질과 이 외에도 영가철, 제오라이트(zeolite) 등의 다양한 물질들을 토양 내 중금속 안정화의 소재로 활용하기 위한 효율성, 적용성 연구가 진행되고 있다. 이들 물질에 대한 토양 적용 후 중금속 안정화 기작은 일부 보고된 바 있으나 장기적 안정성과 현장 적용성을 평가한 연구는 여전히 부족한 실정이다. 본 연구에서는 여러 가지 폐자원을 활용한 선행 연구들에서 제시된 토양 중금속 안정화 관련 내용을 요약하였다.

• Korea-Australia Rheology Journal
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• 제19권4호
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• pp.227-232
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• 2007

The use of various shearing apparatuses to study the phase behavior of poly(styrene-b-isoprene) diblock copolymer micelles is described. A DMTA rheometer was modified so that one can apply oscillatory shear and obtain the scattering pattern along the shear gradient direction. A cone and plate shear cell was designed to access scattering along the shear vorticity direction, and both oscillatory and steady shear can be applied. The most popular way to employ steady shear on relatively low viscosity fluids is to use a Couette cell, because a high shear rate can be readily achieved without disturbing the sample by overflow. In this work, oscillatory shear was used to obtain a single crystal-like scattering pattern, and thereby to examine the mechanism of the thermotropic transition between face-centered cubic (fcc) and body-centered cubic (bcc) lattices. By applying the steady shear, the response of the fcc lattices to various shear rates is discussed.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.9-16
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• 1993

For efficient storage and transmission of medical images, the requirement of image com pression is increasing. Because differences between reconstructed images and original images are related with errors In the diagnosis, lossless compression is generally preferred in mod- ical images. in Run Length Coding which is one of the lossless compression method, we have applied modified scanning direction based on the Hilbert curve, which is a kind of space fill ins curve. We have substituted the traditional raster scanning by Hilbert curve direction scanning. Using this method, we have studied enhancement of compression efficiency for medical images.