• Title/Summary/Keyword: Small Bodies

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Determination of the Synthetic Time and the Transport Pattern of Vicilin and Legumin in Ginseng Endosperm Cell Using Double Immunogold Labeling (이중 면역금입자 표지법을 이용한 인삼 배유세포내 Vicilin과 Legumin의 합성시기 및 수송방식)

  • Lee, Chang-Seob;Yu, Seong-Cheol;Kim, Woo-Kap
    • Journal of Ginseng Research
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    • v.19 no.3
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    • pp.267-274
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    • 1995
  • Vicilin and legumin, the storage Proteins of seed, were Purified from ginseng (Panax ginseng C.A. Meyer) endosperm cells. They were immunized in rabbits, and antibodies were raised respectively. Using these two antibodies, double immunogold labeling of vicilin and legumin was carried out to determine the gap of synthetic time and the transport pattern of vicilin and legumin in the ginseng endosperm cells. Vicilin and legumin were synthesized at the same time at early embryo developmental stage. They were secreted from the Golgi bodies and accumulated into the small vacuoles. As the endosperm cells developed, vicilin and legumin localized in the small vacuoles were gradually transported toward the large central vacuole where they were stored. Protein bodies were derived from the vacuoles filled with proteins and distributed in the endosperm cells of mature red seed. Protein bodies were various in size from 1 to 8 ${\mu}{\textrm}{m}$ in which vicilin and legumin were mixed each other. The number of small particles labeled on the vicilin was greater than that of large particles labeled on the legumin in the protein bodies indicating that the amount of vicilin is higher than that of legumin in the protein bodies.

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Autonomous Landing on Small Bodies based on Discrete Sliding Mode Control (이산 슬라이딩 모드 제어를 이용한 소천체 자율 착륙 기법)

  • Lee, Juyoung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.8
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    • pp.647-661
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    • 2017
  • This paper presents a robust method for autonomously landing on small bodies. Autonomous landing is accomplished by generating and following reference position and attitude profiles. The position and attitude tracking controllers are based on discrete sliding mode control, which explicitly treats the discrete and impulsive natures of thruster operation. Vision-based inertial navigation is used for autonomous navigation for landing. Numerical simulation is carried out to evaluate the performance of the proposed method in a realistic situation with environmental uncertainties.

Survey of Solar System Objects using KMTNet

  • Yang, Hongu;Ishiguro, Masateru;Lee, Hee-Jae;JeongAhn, Youngmin;Moon, Hong-Kyu;Choi, Young-Jun
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.63.1-63.1
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    • 2019
  • Solar system small bodies are unusual objects in astronomical survey data in that they are moving on the celestial sphere. In addition, even in a normal status, their magnitudes are changing over time, firstly because their relative positions with respect to the Sun and Earth are continually changing, secondly because they are rotating bodies with non-spherical shapes. Furthermore, some of them might exhibit unexpected activities, which could be caused by mass ejection or disintegration. Detections and observations of such activities are challenging due to their abrupt nature. Therefore, continuous monitoring observations of large number of Solar system small bodies are required to systematically obtain detailed/transient information about them. Since 2018/2019 winter, we have launched a new project using Korea Microlensing Telescope Network (KMTNet) for detecting such transient phenomena of Solar system objects. Our main goal is to monitor the magnitudes and detect sudden brightness changes. We also plan to discover interesting new objects, and monitor rotational brightness oscillations of asteroids. We intend to monitor the magnitudes of ~ 20,000 known Solar system small bodies per night, and acquire lightcurves of ~ 1,000 asteroids.

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Ultrastructural Changes of Oocytes Related to the Yolk Formadon dudng Oogenesis of Pseudopotamilla occelata Moore (안점의꽃갯지렁이(Pseudopotamilla occelata Moore)의 난모세포의 난황립형성에 따른 미세구조의 변화)

  • 강화선;이양림
    • The Korean Journal of Zoology
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    • v.34 no.2
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    • pp.217-227
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    • 1991
  • Ultrastmctura changes of multivesicular bodies and mitochondria of oocytes of PseudopotamU- Ia occelata Moore were examined with transmission electron microscope in order to follow the process of yolk formation. Yolk granules begin to form at the previtellogenic stages of 50 $\mu$m diameter from multivesicular bodies. Small vesicles and membranous structures within the multivesicular bodies are fused to form the precursors of core bodies of yolk granules. Some vesicles from cytoplasm are also coalesced into the multivesicular bodies. Mature yolk granules are composed of electron-dense core bodies which are seperated from each other by electronopaque small vesicle-like structures. Structural changes of cristae into vesicular shapes and increase in electron density of matrix in mitochondria strongly suggested that mitochondria are in the process of transformation. The transformed mitochondria appear to be basic structures which later become multivesicular bodies.

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Research on Solar System Small Bodies using the Korean Small Telescopes Network

  • Ishiguro, Masateru
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.2
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    • pp.60.4-60.4
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    • 2019
  • Small bodies in the solar system are pristine leftovers of planetesimals since the formation epoch (~4.6 Gyr ago). After the formation, icy planetesimals have been preserved in the distant cold place beyond 30 au (i.e., Trans-Neptunian region) until recently without any catastrophic processes but have just been injected into inner region (<~5 au from the Sun) to be observed as comets. On the contrary, asteroids are rocky primitive objects (although some of them contains icy volatiles) distributing in the mainbelt between Mars and Jupiter orbits. Because of frequent encounters in the mainbelt, asteroids have experienced a number of repeated impacts until the present day. Namely, it is important to investigate thermal alternation process of cometary volatiles and refractories in the solar radiation field, whereas collisional and subsequence phenomena of asteroidal bodies. Although recent spacecraft observations revealed the physical natures on the surfaces of comets and asteroids, their interiors still remain largely unexplored. It is likely that a sudden brightening of a comet is associated with rapid sublimation of internal CO and CO2 or phase transition of amorphous H2O. An episodic dust ejection from an asteroid is causally related to an impact among asteroids, sudden sublimation of remaining subsurficial volatiles, etc. Because these transient phenomena provide rare opportunities to investigate their interiors, immediate observations using any optical instruments are particular important. In my presentation, I will review some examples of such transient phenomena in the solar system and propose possible collaborative research using the Korean Small Telescope Network.

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Methodology for the Observations of Stellar Occultations by Small Bodies of the Solar System

  • Salazar-Manzano, Luis E.;Quintero, Edwin A.
    • Journal of Astronomy and Space Sciences
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    • v.38 no.1
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    • pp.1-21
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    • 2021
  • The observation of stellar occultations constitutes one of the most important techniques for determining the dimensions and establishing the physical parameters of small Solar System bodies. The most substantial calculations are obtained from multiple observations of the same event, which turns the observation of stellar occultations into highly collaborative work and groups teams of observers through international networks. The above situation also requires the participation of both professional and amateur observers in these collaborative networks. With the aim of promoting the participation of professional and amateur groups in the collaborative observation of stellar occultations, we present the methodology developed by the Astronomical Observatory of the Technological University of Pereira (OAUTP) for the observations of occultations due small Solar System bodies. We expose the three fundamental phases of the process: the plan to make observations, the capture of the events, and the treatment of the data. We apply our methodology using a fixed station and a mobile station to observe stellar occultations due to MBAs (354) Eleonora (61) Danae (15112) Arlenewolfe (3915) Fukushima (61788) 2000 QP181 (425) Cornelia (257) Silesia (386) Siegena and (41) Daphne, and due to TNOs 1998BU48 and (529823) 2010 PP81. The positive detections for the objects (257) Silesia (386) Siegena and (41) Daphne allow us to derive lower limits in the diameter of the MBAs of 63.1 km, 166.2 km and 158.7 km and offsets in the astrometric position (Δαc cos��c, Δ��c) of 622.30 ± 0.83, 15.23 ± 9.88 mas, 586.06 ± 1.68, 43.03 ± 13.88 mas and -413.44 ± 9.42, 234.05 ± 19.12 mas, respectively.

CT in Penetrating Wooden Foreign Bodies of Head and Neck (공기음영으로 오인될 수 있는 두경부 영역의 관통성 나무이물에 대한 컴퓨터 전산화 단층촬영의 의의)

  • 오승철;김찬우;박병훈;강인봉;김선태;장일환;차흥억;이선규
    • Korean Journal of Bronchoesophagology
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    • v.4 no.1
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    • pp.142-147
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    • 1998
  • Retained wooden foreign bodies following penetrating trauma are a difficult diagnostic problem. However, penetrating wooden foreign bodies of head and neck have the potential for misinterpretation or failure to detect such foreign bodies on CT. Given the likelihood that such a miss will result in an abscess or neurovascular injury, we present the method with higher window settings, they had a higher attenuation with a unique striated internal architecture and different Hounsfield numbers readily differentiate air and non-air hypodense material such as fat, or possibly wood. Being aware of the potential appearance of wood, we may also find CT useful in excluding small retained fragments in postoperative patients with persistent symptoms. This article presents two cases in which wooden foreign bodies of head and neck were present with CT evaluation.

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Retrospective Study of 143 Dogs with Alimentary Foreign Bodies (개에서 발생한 소화기계 이물에 대한 회고분석 - 143 증례)

  • Choi, Jihye;Keh, Seoyeon;Kim, Hyunwook
    • Journal of Veterinary Clinics
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    • v.32 no.1
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    • pp.49-55
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    • 2015
  • This study was retrospectively investigated the clinical features, diagnostic imaging, treatment, and prognosis of foreign bodies according to alimentary site and type of foreign body, in 143 dogs. Among 28 breeds, Maltese, Shih Tzu, and terriers including the Yorkshire terrier were presented with high prevalence. Bone was the most commonly identified (33%) foreign body regardless of alimentary site. Approximately 76% of foreign bodies were in the stomach and small intestine. All esophageal foreign bodies were diagnosed on survey radiography, with the most common location being the caudal thoracic esophageal segment. Further diagnostic examinations including ultrasonography or contrast studies were additionally performed to detect radiolucent foreign bodies and perforation or leakage in the stomach and intestine. However, most seeds could be identified based on the characteristic features such as hyperdense thin double lines and inner gas on survey radiography. In conclusion, complications such as peritonitis and intestinal perforation were mainly observed in cases with seeds and linear foreign bodies. Especially, fabric foreign bodies could be induce peritonitis and re-perforation with high prevalence after surgical correction.

Dynamics of Extra-Vehicular Activities in Low-Gravity Surface Environments

  • Spencer, David A.;Gast, Matthew A.
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.1
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    • pp.11-18
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    • 2013
  • Human spaceflight experience in extra-vehicular activity (EVA) is limited to two regimes: the micro-gravity environment of Earth orbit, and the lunar surface environment at one-sixth of Earth's gravity. Future human missions to low-gravity bodies, including asteroids, comets, and the moons of Mars, will require EVA techniques that are beyond the current experience base. In order to develop robust approaches for exploring these small bodies, the dynamics associated with human exploration on low-gravity surface must be characterized. This paper examines the translational and rotational motion of an astronaut on the surface of a small body, and it is shown that the low-gravity environment will pose challenges to the surface mobility of an astronaut, unless new tools and EVA techniques are developed. Possibilities for addressing these challenges are explored, and utilization of the International Space Station to test operational concepts and hardware in preparation for a low-gravity surface EVA is discussed.

Development Plan for the Sanhakyeon Consortium (중소기업 발전을 위한 산학연 컨소시엄 공동기술 개발)

  • Park Roh Gook
    • Proceedings of the Korean Society for Quality Management Conference
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    • 2004.04a
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    • pp.556-563
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    • 2004
  • For the activation of the Sanhakyeon Consortium, the role of local universities is critical. It is necessary for the university professionals to bring forth detailed alternative plans to upgrade the technological power of the inferior local small & medium enterprises. This means that the local self-governing bodies must database local universities and professional personnel. As a result, the professionals that are needed by enterprises must be designated to those businesses. Also, the regional small and medium enterprises must develop research personnel to enhance their power of technology. To make this possible, the participating companies of Sanhakyeon Consortium should support the students who are participating in the Consortium with research funds, and also should consider how these students can work for those companies after graduation. Finally, the local self-governing bodies must support Sanhak's cooperative research on locally specialized Industries, by forming a technology-human power network between local universities and small Sl medium enterprises.

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