نتایج جستجو برای: propeller
تعداد نتایج: 3766 فیلتر نتایج به سال:
Quantitative abdominal T(2) measurements may be useful for lesion differentiation and functional tissue characterization. However, T(2) mapping of the abdomen with conventional spin-echo (SE) and turbo-spin-echo (TSE) approaches can be challenging due to physiologic motion artifacts. Multishot TSE-based PROPELLER (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction) can...
The form of a real AT-body fermion wave function when expanded in Slater determinants of natural orbitals is investigated using a computer. I t is found that in the case when the number of natural orbitals is N f 2 there is a considerable reduction in the number of Slater determinants required. This offers the possibility of calculating atomic wave functions which are significantly more accurat...
Periodically rotated overlapping parallel lines with enhanced reconstruction-echo-planar imaging (PROPELLER-EPI) is a multishot technique that samples k-space by acquisition of narrow blades, which are subsequently rotated until the entire k-space is filled. It has the unique advantage that the center of k-space, and thus the area containing the majority of functional MRI signal changes, is sam...
PROPELLER technique is widely used in MRI examinations for being motion insensitive, but it prolongs scan time and is restricted mainly to T2 contrast. Parallel imaging can accelerate PROPELLER and enable more flexible contrasts. Here, we propose a multi-step joint-blade (MJB) SENSE reconstruction to reduce the noise amplification in parallel imaging accelerated PROPELLER. MJB SENSE utilizes th...
In AE Aqr, magnetic fields transfer energy and angular momentum from a rapidly spinning white dwarf to material in the gas stream from the companion star, with the effect of spinning down the white dwarf while flinging the gas stream material out of the binary system. This magnetic propeller produces a host of observable signatures, chief among which are broad single-peaked flaring emission lin...
Polyethylene glycol binding alters human telomere G-quadruplex structure by conformational selection
Polyethylene glycols (PEGs) are widely used to perturb the conformations of nucleic acids, including G-quadruplexes. The mechanism by which PEG alters G-quadruplex conformation is poorly understood. We describe here studies designed to determine how PEG and other co-solutes affect the conformation of the human telomeric quadruplex. Osmotic stress studies using acetonitrile and ethylene glycol s...
Quiet PROPELLER MRI techniques match the quality of conventional PROPELLER brain imaging techniques.
BACKGROUND AND PURPOSE Switching of magnetic field gradients is the primary source of acoustic noise in MR imaging. Sound pressure levels can run as high as 120 dB, capable of producing physical discomfort and at least temporary hearing loss, mandating hearing protection. New technology has made quieter techniques feasible, which range from as low as 80 dB to nearly silent. The purpose of this ...
So far, only a few of the interactions between the ≈ 30 nucleoporins comprising the modular structure of the nuclear pore complex have been defined at atomic resolution. Here we report the crystal structure, at 2.6 Å resolution, of a heterotrimeric complex, composed of fragments of three cytoplasmically oriented nucleoporins of yeast: Nup82, Nup116, and Nup159. Our data show that the Nup82 frag...
The aM subunit of integrin Mac-1 contains several distinct regions in its extracellular segment. The N-terminal region has been predicted to fold into a b-propeller domain composed of seven b-sheets each about 60 amino acid residues long, with the I-domain inserted between b-sheets 2 and 3. The structure of the C-terminal region is unknown. We have used monoclonal antibodies (mAbs) as probes to...
Keap1 is a substrate adaptor of a Cullin 3-based E3 ubiquitin ligase complex that recognizes Nrf2, and also acts as a cellular sensor for xenobiotics and oxidative stresses. Nrf2 is a transcriptional factor regulating the expression of cytoprotective enzyme genes in response to such stresses. Under unstressed conditions Keap1 binds Nrf2 and results in rapid degradation of Nrf2 through the prote...
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