http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Sessile Serrated Adenomas: How to Detect, Characterize and Resect
( Michael X. Ma ),( Michael J. Bourke ) 대한간학회 2017 Gut and Liver Vol.11 No.6
Serrated polyps are important contributors to the burden of colorectal cancers (CRC). These lesions were once consid-ered to have no malignant potential, but currently up to 30% of all CRC are recognized to arise from the serrated neopla-sia pathway. The primary premalignant lesions are sessile serrated adenomas/polyps (SSA/Ps), although traditional serrated adenomas are relatively uncommon. Compared to conventional adenomas, SSA/Ps are morphologically subtle with indistinct borders, may be difficult to detect endoscopi-cally, are more prevalent than previously thought, are as-sociated with synchronous and metachronous advanced neoplasia, and have a higher risk of incomplete resection. Al-though many lesions remain “dormant,” progressive disease is associated with the development of dysplasia and more rapid progression to CRC. As a result, SSA/Ps are strongly implicated in the development of interval cancers. These fac-tors represent unique challenges that require a meticulous approach to their management. In this review, we sum-marize the contemporary literature on the characterization, detection and resection of SSA/Ps. (Gut Liver 2017;11:747-760)
Kim, Hyo Jeong,Evans II, Neal J.,Dunham, Michael M.,Chen, Jo-Hsin,Lee, Jeong-Eun,Bourke, Tyler L.,Huard, Tracy L.,Shirley, Yancy L.,De Vries, Christopher IOP Publishing 2011 The Astrophysical journal Vol.729 No.2
<P>We present new observations of the CB130 region composed of three separate cores. Using the Spitzer Space Telescope, we detected a Class 0 and a Class II object in one of these, CB130-1. The observed photometric data from Spitzer and ground-based telescopes are used to establish the physical parameters of the Class 0 object. Spectral energy distribution fitting with a radiative transfer model shows that the luminosity of the Class 0 object is 0.14-0.16 L-circle dot, which is low for a protostellar object. In order to constrain the chemical characteristics of the core having the low-luminosity object, we compare our molecular line observations to models of lines including abundance variations. We tested both ad hoc step function abundance models and a series of self-consistent chemical evolution models. In the chemical evolution models, we consider a continuous accretion model and an episodic accretion model to explore how variable luminosity affects the chemistry. The step function abundance models can match observed lines reasonably well. The best-fitting chemical evolution model requires episodic accretion and the formation of CO2 ice from CO ice during the low-luminosity periods. This process removes C from the gas phase, providing a much improved fit to the observed gas-phase molecular lines and the CO2 ice absorption feature. Based on the chemical model result, the low luminosity of CB130-1 is explained better as a quiescent stage between episodic accretion bursts rather than being at the first hydrostatic core stage.</P>
Lee, Jeong-Eun,Lee, Ho-Gyu,Shinn, Jong-Ho,Dunham, Michael M.,Kim, Il-Suk,Kim, Chang Hee,Bourke, Tyler L.,Evans, Neal J.,Choi, Yunhee IOP Publishing 2010 ASTROPHYSICAL JOURNAL LETTERS - Vol.709 No.1
<P>A long infrared jet has been discovered by the Spitzer c2d Legacy Program in core A of L1251. It is associated with a very embedded Class 0 object with an accretion luminosity of about 0.9 L(circle dot) derived by radiative transfer model fitting to the observed spectral energy distribution. Comparing the observed Infrared Array Camera colors along the infrared jet with those calculated from a model of an admixture of gas with a power-law temperature distribution indicates that the jet is possibly created by a paraboloidal bow shock propagating into the ambient medium of n(H(2)) = 10(5) cm(-3). In addition, the variation of the power-law index along the jet suggests that the portion of hot gas decreases with distance from the jet engine. The molecular outflow in this region has been mapped for the first time using CO data. From the calculated outflow momentum flux, a very strong lower limit to the average accretion luminosity is 3.6 sin i/cos(3) i L(circle dot), indicative of a decrease in the accretion rate with time.</P>