We introduce the concept of orbit-homogeneity of permutation groups: a group G is orbit thomogeneous if two sets of cardinality t lie in the same orbit of G whenever their intersections with each G-orbit have the same cardinality. For transitive groups, this coincides with the usual notion of t-homogeneity. This concept is also compatible with the idea of partition transitivity introduced by Ma...

Introduction: Double Inversion Recovery (DIR) [1] is a valuable tool for the diagnosis of cortical and/or sub cortical lesions [2]. By introducing non-selective 3D acquisitions the problem of inherent CSF-inflow artifacts and partial volume effects in DIR images have been reduced, substantially improving the sensitivity and specificity of detecting sub-millimeter lesions . Successful implementa...

Introduction Myelin water imaging has been successfully used to assess myelin content in human and animal CNS tissue [1,2]. It has been shown that myelin water fraction (MWF) [3] correlates well with the amount of myelin in a rat model of spinal cord injury (SCI) [2] and can therefore be an important marker of the cord pathology. Quantitative T2 measurements used in myelin water imaging require...

total igm, iga, and igm-rheumatoid factor (rf) and iga-rf were quantitated in the serum and synovial fluid of 35 seropositive and 8 seronegative rheumatoid arthritis (ra) patients, using a sensitive enzyme-linked immunosorbent assay (elisa). mononuclear cells isolated from peripheral blood and synovial fluid of three seropositive patients were also stimulated in vitro with phorbol myristate ace...

Introduction Micro-scale inductively coupled rf resonators enable wireless investigation of small sample volumes in a conventional NMR spectrometer. The inductively coupled approach has the advantage of focussing the sensitivity and rf power on the small sample volume, without the need for any connections to the spectrometer. Preceding research demonstrated that inductively coupled coils can in...

Fully polarimetric synthetic aperture radar (PolSAR) has the advantage for working at all time and all weather compared with optical remote sensing. It can provide four channel data, including HH, HV, VH, and VV, which is usually called sinclair matrix. The sinclair matrix can be used to describe the relative pure targets. Concerning to the distributed targets, it is necessary to use coherence ...

Introduction Whole body MRI at 3T may be impeded by B1 transmit field inhomogeneities caused by the dielectric shortening of the RF wavelength [1]. RF shimming techniques based on parallel transmission [2,3] can strongly improve the image quality in clinical whole body applications [4]. In this context, it is an important question, how the RF shimming performance depends on the chosen coil topo...