• Title/Summary/Keyword: Harvard University

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Fluorescence Molecular Imaging

  • Choi, Heung-Kook;Ntziachristos, Vasilis;Weissleder, Ralph
    • Proceedings of the KSMRM Conference
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    • 2004.09a
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    • pp.23-32
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    • 2004
  • The chemotherapy sensitive Lewis lung carcinoma (LLC) and chemotherapy resistant Lewis lung carcinoma (CR-LLC) tumors concurrently implanted in mice, and compare these findings with histological macroscopic observations against 3D reconstruction of Fluorescence Molecular Tomography (FMT) preformed in vivo on the same animals. For the 3D image reconstruction we used 32 laser source images, a flat image and 3D surface rendering that confused for 3D Fluorescence Molecular Imaging (FMI). A minimum of ten tissue sections were analyzed per tumor for quantification of the TUNEL-positive cells, cell-associated Cy5.5-Annexin and vessel-associated Alexa Fluor-Lectin. These are useful apoptosis and angiogenesis markers, and they serve as validation experiments to data obtained in vivousing a Cy5.5-Annexin V conjugate injected intravenously in chemotherapy-treated animals carrying the tumors studied histologically. We detected higher levels of apoptosis and corresponding higher levels of Cy5.5 fluorescence in the LLC vs. the CR-LLC tumors according to tissue depth and these findings confirm that in vivo staining with the Cy5.5-Annexing conjugate correlates well with in vitro TUNEL staining and is consistent with the higher apoptotic index expected from the LLC line. There appeared to be 1.38% more apoptosis for LLC than CR-LLC. Consequently there is good correlation between the histology results and in vivo fluorescence-mediated optical imaging. In conclusion the apoptotic images of 3D FMI were validated by microscopic histological image analysis. This is a significant result for the continuous progress of fluorescence 3D imaging research.

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Altered expression of norepinephrine transporter and norepinephrine in human placenta cause pre-eclampsia through regulated trophoblast invasion

  • Na, Kyu-Hwan;Choi, Jong Ho;Kim, Chun-Hyung;Kim, Kwang-Soo;Kim, Gi Jin
    • Clinical and Experimental Reproductive Medicine
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    • v.40 no.1
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    • pp.12-22
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    • 2013
  • Objective: We investigated the norepinephrine transporter (NET) expression in normal and pre-eclamptic placentas and analyzed the invasion activity of trophoblastic cells based on norepinephrine (NE)-NET regulation. Methods: NET and NE expression levels were examined by western blot and enzyme-linked immunosorbent assay, respectively. Trophoblast invasion activity, depending on NE-NET regulation, was determined by NET-small interfering RNA (siRNA) and NET transfection into the human extravillous trophoblast cells with or without NE treatment and invasion rates were analyzed by zymography and an invasion assay. Results: NET mRNA was expressed at a low level in pre-eclamptic placentas compared with normal placentas and NE concentration in maternal plasma increased significantly in pre-eclamptic women compared to normal pregnant women (p<0.05). NET gene upregulation and NE treatment stimulated trophoblast cell invasion up to 2.5-fold (p<0.05) by stimulating matrix metalloproteinase-9 activity via the phosphoinositol-3-kinase/AKT signaling pathway, whereas NET-siRNA with NE treatment reduced invasion rates. Conclusion: NET expression is reduced by inadequate regulation of NE levels during placental development. This suggests that a complementary balance between NET and NE regulates trophoblast cell invasion activities during placental development.

Mass constraint and temperature estimation of eruptive plasma in X-ray

  • Lee, Jin-Yi;Raymond, John C.;Reeves, Katharine K.;Moon, Yong-Jae;Kim, Kap-Sung
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.60.2-60.2
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    • 2013
  • We investigate several eruptive hot plasma observations by Hinode/XRT. Their corresponding EUV and/or white light CME features are visible in some events. Using those observations, we determine the mass constraints of eruptive plasma by assuming simplified geometrical structures of the plasma. In some events, their associated prominence eruptions and eruptive plasma were observed in EUV observations as absorption or emission features. The absorption feature provides the lower limit to the cold mass while the emission feature provides the upper limit to the mass of observed eruptive plasma in X-ray and EUV passbands. We compare the mass constraints for each temperature responses and find that the mass in EUV and XRT are smaller in their upper or lower limit than total mass in coronagraph. About half eruptive events in XRT have no corresponding CME, which may be due to failed eruptions or low plasma density. In addition, some events were observed by a few passbands in X-ray, which allows the determination of the eruptive plasma temperature using a filter ratio method. We present the isothermal plasma temperatures by the filter ratio method. These are possibly an average temperature for higher temperature plasma because the XRT is more sensitive in higher temperature.

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A Study on Sama Pangmok in Harvard-Yenching Library (하버드옌칭도서관 소장 사마방목(司馬榜目)에 관한 고찰)

  • Han, Mejing
    • Journal of Korean Society of Archives and Records Management
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    • v.2 no.2
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    • pp.107-135
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    • 2002
  • This study concerns Sama Pangmok which is in the possession of Harvard-Yenching Library, Harvard University, USA. Sama Pangmok is the archive of Saengwon Chinsa Examination(the licentiate examination) which is the preliminary test for main civil service examination. And it is the list of the names of the applicants who passed this examination. This examination were conducted from the days of lauching of Chosun as a new nation to the days of Kabo Kyungjang(the 1894 reform). While this examination was conducted 230 times, not all but 186 of the resultant lists are available. Of these 186 lists, this library posses 47 titles. My study of the existing dissertation on the possession of titles by Harvard-Yenching Library, 7 titles where in possession of the same library in 1968 and 5 ones in 190. It is the main objective of this study to clarify the possession of this library and correct the past errors in indication of possession of titles by this library. For this purpose, I conducted a study on Saengwon Chinsa Examination and Sama Pangmok, which could be the historical background of this study. This was followed by research on the bibliographical aspect of Sama Pangmok and the research on the situation concerning this Library's possession of the same lists. Lastly, the analysis of the special feature of Sama Pangmok possessed by this Library was conducted. It is expected that the result of this research will be applied to the practical research of the history of civil service examinations and the old and rare books overseas in the future.

An inventory of Korean living collections in the Arnold Arboretum of Harvard University, USA

  • Lee, Sang Jun;Kim, Jung-Hyun;Nam, Gi-Heum;Kim, Min-Ha;Lim, Chae Eun
    • Journal of Species Research
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    • v.3 no.2
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    • pp.183-194
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    • 2014
  • As part of a study to understand the current status of Korean plant species propagated in foreign countries, we conducted extensive surveys on Korean living collections in the Arnold Arboretum of Harvard University, the oldest public arboretum in North America. Specifically, we collected and identified the voucher specimens of the living collections and further examined the collection databases to understand the history of how Korean plants were introduced to the Arboretum. We found that a total of 154 Korean taxa (belonging to 49 families and 81 genera) have been planted in the arboretum. Most plants originated from seeds that were directly collected in Korea or obtained via seed exchanges with botanical gardens in Asia, Europe, and U.S.A. Of the 154 taxa, 16 are Korean endemic species, and three are listed as endangered species. In addition, 62 taxa are as floristic regional indicator species of Korea used by the Ministry of Environment.

Advances in the design of macroporous polymer scaffolds for potential applications in dentistry

  • Bencherif, Sidi A.;Braschler, Thomas M.;Renaud, Philippe
    • Journal of Periodontal and Implant Science
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    • v.43 no.6
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    • pp.251-261
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    • 2013
  • A paradigm shift is taking place in medicine and dentistry from using synthetic implants and tissue grafts to a tissue engineering approach that uses degradable porous three-dimensional (3D) material hydrogels integrated with cells and bioactive factors to regenerate tissues such as dental bone and other oral tissues. Hydrogels have been established as a biomaterial of choice for many years, as they offer diverse properties that make them ideal in regenerative medicine, including dental applications. Being highly biocompatible and similar to native extracellular matrix, hydrogels have emerged as ideal candidates in the design of 3D scaffolds for tissue regeneration and drug delivery applications. However, precise control over hydrogel properties, such as porosity, pore size, and pore interconnectivity, remains a challenge. Traditional techniques for creating conventional crosslinked polymers have demonstrated limited success in the formation of hydrogels with large pore size, thus limiting cellular infiltration, tissue ingrowth, vascularization, and matrix mineralization (in the case of bone) of tissue-engineered constructs. Emerging technologies have demonstrated the ability to control microarchitectural features in hydrogels such as the creation of large pore size, porosity, and pore interconnectivity, thus allowing the creation of engineered hydrogel scaffolds with a structure and function closely mimicking native tissues. In this review, we explore the various technologies available for the preparation of macroporous scaffolds and their potential applications.