نتایج جستجو برای: diffusion length

تعداد نتایج: 465368  

Journal: :Magnetic resonance imaging 2001
R W Mair M D Hürlimann P N Sen L M Schwartz S Patz R L Walsworth

We have extended the utility of NMR as a technique to probe porous media structure over length scales of approximately 100-2000 microm by using the spin 1/2 noble gas 129Xe imbibed into the system's pore space. Such length scales are much greater than can be probed with NMR diffusion studies of water-saturated porous media. We utilized Pulsed Gradient Spin Echo NMR measurements of the time-depe...

Journal: :iranian journal of public health 0
sa alemohammad dd farhud m hooshmand m sanati p derakhshandeh-peykar sj imam

a 9 bp deletion between cytochrome oxidase subunit ii and trna lys genes in mitochondrial dna, has proven to be an extremely informative marker for tracing population history. using the pcr-page and pcr-sscp techniques in this study, 152 dna samples collected from iranian populations were screened for the 9 bp deletion. no deletion was observed. a length polymorphism, most probably a 9 bp tripl...

Journal: :Journal of neurotrauma 2013
Michael B Jirjis Shekar N Kurpad Brian D Schmit

The aim of this study was to characterize magnetic resonance diffusion tensor imaging (DTI) in proximal regions of the spinal cord following a thoracic spinal cord injury (SCI). Sprague-Dawley rats (n=40) were administered a control, mild, moderate, or severe contusion injury at the T8 vertebral level. Six direction diffusion weighted images (DWIs) were collected ex vivo along the length of the...

Journal: :Technology and innovation 2016
Laurie M Baker Ryan P Cabeen Sarah Cooley David H Laidlaw Robert H Paul

This paper reviews basic methods and recent applications of length-based fiber bundle analysis of cerebral white matter using diffusion magnetic resonance imaging (dMRI). Diffusion weighted imaging (DWI) is a dMRI technique that uses the random motion of water to probe tissue microstructure in the brain. Diffusion tensor imaging (DTI) is an extension of DWI that measures the magnitude and direc...

Journal: :JCP 2010
Zhihong Li Zhu Tao Wendi Lai

Communities of practices (Cops) can improve organizational performance by effectively promoting knowledge diffusion, and recently they were receiving increasing attention from organizations in abroad. The aim of our study was to further explore how to cultivate and support Communities of practice. According to some literatures, we first studied what is the most important influencing factor of k...

2010
Sang Il Choi Joon-Won Kang Eun Ju Chun Seong Hoon Choi Tae-Hwan Lim

OBJECTIVE We wanted to evaluate the effect of the number of diffusion-sensitizing gradient directions on the image quality for evaluating myocardial anisotropy and fiber tracking by using in vitro diffusion tensor MR imaging (DT-MRI). MATERIALS AND METHODS The DT-MR images, using a SENSE-based echoplanar imaging technique, were acquired from ten excised porcine hearts by using a 3T MR scanner...

2008
Sebastian Meier Adrian Muntean

We investigate a reaction–diffusion process in a two-phase medium with microscopic length scale ε. The diffusion coefficients in the two phases are highly different (d1/D = ε2) and the reaction constant k is large. First, the homogenisation limit ε → 0 is taken, which leads to a two-scale model. Afterwards, we pass to the fast-reaction limit k →∞ and obtain a two-scale reaction-diffusion system...

1997
Woei Wu Pai Anna K. Swan Zhenyu Zhang J. F. Wendelken

The diffusion and coarsening of two-dimensional homoepitaxial islands on Cu(100) and Ag(100) surfaces have been studied at room temperature with time-sequenced scanning tunneling microscopy. Quantitative analyses of the dependence of island diffusion coefficient D vs the island side length L, D ~ L , yield noninteger scaling exponents which are consistent with island coalescence. Moreover, the ...

Journal: :Physical review letters 2007
M Paul Lettinga Eric Grelet

We report the direct visualization at the scale of single particles of mass transport between smectic layers, also called permeation, in a suspension of rodlike viruses. Self-diffusion takes place preferentially in the direction normal to the smectic layers, and occurs by quasiquantized steps of one rod length. The diffusion rate corresponds with the rate calculated from the diffusion in the ne...

2016
Sato Eida Marc Van Cauteren Yuka Hotokezaka Ikuo Katayama Miho Sasaki Makoto Obara Tomoyuki Okuaki Misa Sumi Takashi Nakamura

Corrigendum: Length of intact plasma membrane determines the diffusion properties of cellular water Sato Eida, Marc Van Cauteren, Yuka Hotokezaka, Ikuo Katayama, Miho Sasaki, Makoto Obara, Tomoyuki Okuaki, Misa Sumi & Takashi Nakamura Scientific Reports 6:19051; doi: 10.1038/srep19051; published online 11 January 2016; updated on 20 May 2016 This Article contains errors. In Figure 1j, the x-axi...

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