• Title/Summary/Keyword: metabolic reconstruction

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Representation Techniques for 4-Dimensional MR Images

  • Homma, Kazuhiro;Takenaka, Kenji;Nakai, Yoshihiko;Hirose, Takeshi
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.429-431
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    • 2002
  • Metabolic analysis of biological tissues, the interventional radiology in MRT (Magnetic Resonance Treatment) and for clinical diagnoses, representation of 4-Dimensional (4D) structural information (x,y,z,t) of biological tissues is required. This paper discusses image representation techniques for those 4D MR Images. We have proposed an image reconstruction method for ultra-fast 3D MRI. It is based on image interpolation and prediction of un-acquired pictorial data in both of the real and the k-space (the acquisition domain in MRI). A 4D MR image is reconstructed from only two 3D MR images and acquired a few echo signals that are optimized by prediction of the tissue motion. This prediction can be done by the phase of acquired echo signal is proportioned to the tissue motion. On the other hand, reconstructed 4D MR images are represented as a 3D-movie by using computer graphics techniques. Rendered tissue surfaces and/or ROIs are displayed on a CRT monitor. It is represented in an arbitrary plane and/or rendered surface with their motion. As examples of the proposed representation techniques, the finger and the lung motion of healthy volunteers are demonstrated.

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Flavonoid Metabolic Engineering for Modification of Flower Color in Chrysanthemum (국화 꽃색 변경을 위한 플라보노이드 대사공학)

  • Kim, Da-Hye;Park, Sangkyu;Park, Bo-Ra;Lee, Jong-Yeol;Lim, Sun-Hyung
    • Korean Journal of Breeding Science
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    • v.50 no.4
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    • pp.351-363
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    • 2018
  • In ornamental crops, the color and shape of flowers are one of the important traits. Generally, flower colors are determined by accumulating pigments such as carotenoids, flavonoids, and betalains. Among them, flavonoids are responsible for broad ranges of colors. Chrysanthemums are one of the most popular ornamental crops in the world, and there have been many efforts to change their flower color. In chrysanthemum flowers, cyanidin-based anthocyanin confers pink or red color, whereas terpenoid-based carotenoids are mainly responsible for yellow and green colors. However, blue colored chrysanthemums do not occur in nature. To date, there have been attempts to obtain blue or violet-colored chrysanthemum flowers through the introduction of a novel gene for accumulating delphinidin-based anthocyanins, while other studies have reported changing endogenous metabolites through the reconstruction of flavonoid biosynthesis. Since various transcription factors are involved in the regulation of flavonoid biosynthesis, it is important to understand not only the structural genes, but also the transcription factors required for the modification of flavonoid-based flower color. Therefore, in this paper, we describe the flavonoid biosynthetic pathway and its regulation, and review previous studies on the change in flower color through modification of flavonoid biosynthesis. This effort could be an important milestone in successfully achieving the modification of chrysanthemum flower color by means of plant biotechnology.

Recent Advances in Nuclear Medicine Imaging Instrumentation (핵의학 영상기기의 최근 진보)

  • Jung, Jin-Ho;Choi, Yong;Hong, Key-Jo;Min, Byung-Jun;Hu, Wei;Kang, Ji-Hoon
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.2
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    • pp.98-111
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    • 2008
  • This review introduces advances in clinical and pre-clinical single photon emission computed tomography (SPECT) and positron emission tomography (PET) providing noninvasive functional images of biological processes. Development of new collimation techniques such as multi-pinhole and slit-slat collimators permits the improvement of system spatial resolution and sensitivity of SPECT. Application specific SPECT systems using smaller and compact solid-state detector have been customized for myocardial perfusion imaging with higher performance. Combined SPECT/CT providing improved diagnostic and functional capabilities has been introduced. Advances in PET and CT instrumentation have been incorporated in the PET/CT design that provide the metabolic information from PET superimposed on the anatomic information from CT. Improvements in the sensitivity of PET have achieved by the fully 3D acquisition with no septa and the extension of axial field-of-view. With the development of faster scintillation crystals and electronics, time-of-flight (TOF) PET is now commercially available allowing the increase in the signal-to-noise ratio by incorporation of TOF information into the PET reconstruction process. Hybrid PET/SPECT/CT systems has become commercially available for molecular imaging in small animal models. The pre-clinical systems have improved spatial resolution using depth-of-interaction measurement and new collimators. The recent works on solid state detector and dual modality nuclear medicine instrumentations incorporating MRI and optical imagers will also be discussed.

A Case Report of Holoprosencephaly (전전뇌증(Holoprosencephaly)의 증례보고)

  • Song, Seung Han;Kang, Nak Heon
    • Archives of Plastic Surgery
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    • v.34 no.4
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    • pp.528-530
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    • 2007
  • Purpose: Holoprosencephaly(HPE) is a rare developmental defect due to incomplete cleavages of the prosencephalon during the third week of fetal development. Chromosomal anomalies, genetic syndrome, teratogen, or genetic disorder of non-syndromic HPE are usually accepted as etiology. The consequences of prechordal mesoderm defect are varying degrees of deficit of midline facial development, especially the median nasal process(premaxilla), and incomplete morphogenesis of the forebrain. We experienced a case of lobar HPE with complete cleft lip and palate. Methods: A female newborn infant was born at $38^{+6}$ weeks' gestational age via NSVD. The infant's birth weight was 3.6 kg, height 52 cm, and head circumference 32.5 cm, showing microcephaly, flat nose, median complete cleft lip & palate, and hypotelorism, along with defects of midfacial development including losses of premaxilla, philtrum, nasal septum, and columella. Results: There were no specific findings noted from the head and neck X-ray and tests for endocrine and metabolic disorders, but clinical characteristics of midface and dysgenesis corpus callosum on brain MRI were seen, so that this case was diagnosed with HPE. Conclusion: HPE is divided into three categories of alobar, semilobar, and lobar prosencephaly according to the degree of cerebral hemisphere separation. Assesment of patient's brain abnormality and malformation is essential in determining the extent and benefit of surgical intervention. This case was included in the lobar type HPE which shows relatively good prognosis compared with other types and reconstruction of median complete cleft lip & palate and midfacial defects will be performed.

Short Bowel Syndrome as the Leading Cause of Intestinal Failure in Early Life: Some Insights into the Management

  • Goulet, Olivier;Nader, Elie Abi;Pigneur, Benedicte;Lambe, Cecile
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.22 no.4
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    • pp.303-329
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    • 2019
  • Intestinal failure (IF) is the critical reduction of the gut mass or its function below the minimum needed to absorb nutrients and fluids required for adequate growth in children. Severe IF requires parenteral nutrition (PN). Pediatric IF is most commonly due to congenital or neonatal intestinal diseases or malformations divided into 3 groups: 1) reduced intestinal length and consequently reduced absorptive surface, such as in short bowel syndrome (SBS) or extensive aganglionosis; 2) abnormal development of the intestinal mucosa such as congenital diseases of enterocyte development; 3) extensive motility dysfunction such as chronic intestinal pseudo-obstruction syndromes. The leading cause of IF in childhood is the SBS. In clinical practice the degree of IF may be indirectly measured by the level of PN required for normal or catch up growth. Other indicators such as serum citrulline have not proven to be highly reliable prognostic factors in children. The last decades have allowed the development of highly sophisticated nutrient solutions consisting of optimal combinations of macronutrients and micronutrients as well as guidelines, promoting PN as a safe and efficient feeding technique. However, IF that requires long-term PN may be associated with various complications including infections, growth failure, metabolic disorders, and bone disease. IF Associated Liver Disease may be a limiting factor. However, changes in the global management of IF pediatric patients, especially since the setup of intestinal rehabilitation centres did change the prognosis thus limiting "nutritional failure" which is considered as a major indication for intestinal transplantation (ITx) or combined liver-ITx.