269 research outputs found
MRI and CT features of a malignant myoepithelioma of the scrotum : A case report and literature review
Malignant myoepithelioma of the scrotum is extremely rare. We report the case of a 51-year-old man with malignant myoepithelioma of the scrotum, wherein computed tomography and magnetic resonance imaging revealed a lobulated soft tissue mass with calcification, cystic component, and solid component with gradual contrast enhancement on dynamic contrast-enhanced scans. The patient presented with scrotal induration, and there was no elevation of tumor markers and no evidence of a metastatic lesion on computed tomography and magnetic resonance imaging. Histopathological examination of the resected scrotal specimen confirmed a well-circumscribed solid tumor with septa, a small area of hemorrhage, and necrosis. The subsequent diagnosis was malignant myoepithelioma of the scrotum. This case shows that scrotal malignant myoepithelioma might appear as a well-defined lobulated mass with cystic regions. We conjecture that the enhancement pattern and apparent diffusion coefficient values can be potential markers for scrotal myoepithelial tumors
NMR Line Shape Analysis of a Multi-state Ligand Binding Mechanism in Chitosanase
Chitosan interaction with chitosanase was examined through analysis of spectral line shapes in the NMR HSQC titration experiments. We established that the substrate, chitosan hexamer, binds to the enzyme through the three-state induced-fit mechanism with fast formation of the encounter complex followed by slow isomerization of the bound-state into the final conformation. Mapping of the chemical shift perturbations in two sequential steps of the mechanism highlighted involvement of the substrate-binding subsites and the hinge region in the binding reaction. Equilibrium parameters of the three-state model agreed with the overall thermodynamic dissociation constant determined by ITC. This study presented the first kinetic evidence of the induced-fit mechanism in the glycoside hydrolases
Measuring effective orifice area of bileaflet mechanical valves in patients after aortic valve replacement using phase-contrast cine MR imaging
POSTER PRESENTATION2011 SCMR/Euro CMR Joint Scientific Sessions / Nice, France / 3-6 February 201
Bis(1H-imidazole-κN 3){2,2′-[propane-1,2-diylbis(nitrilomethylidyne)]diphenolato-κ4 O,N,N′,O′}iron(III) perchlorate
The title compound, [Fe(C17H16N2O2)(C3H4N2)2]ClO4, consists of monomeric [Fe(salmen)(HIm)2]+ cations {salmen is the 2,2′-[propane-1,2-diylbis(nitrilomethylidyne)]diphenolate dianion and HIm is 1H-imiazole} and perchlorate anions. In the cation, the Fe3+ ion is octahedrally coordinated by two N atoms and two O atoms from a tetradentate salmen anion and two N atoms from two Him molecules. These ligands are coordinated to the iron ion in a direction perpendicular to the [Fe(salmen)]+ coordination plane. The benzene ring planes in the salmen ligands are oriented nearly parallel to one another intermolecularly [dihedral angle = 6.36 (3)°]. The dihedral angle between the mean planes through the imidazole rings in the cation is 76.9 (2)°. In the crystal, N—H⋯O interactions link the molecules into a one-dimensional double chain running along [101] and C—H⋯O interactions link the double chains into a two-dimensional network, running parallel to the ac plane
Raman scattering study of ca-modified lead titanate
The paraelectric to ferroelectricphase transitionswere studied by Raman scattering in Ca-doped leadtitanate ceramics. The soft optic modes responsible for theferroelectricphase transitions were clearly observed. TheAi(lTO) mode, which softens toward Tc, contains four subpeaks.The frequencies of these subpeaks depend to a greatextent on the Ca content and the temperature. These behaviorsare discussed on the basis of the anharmonicity oflatticevibrations
Preoperative Graft Volume Assessment with 3D-CT Volumetry in Living-Donor Lobar Lung Transplantations
To determine the effectiveness of living-donor lobar lung transplantation (LDLLT), it is necessary to predict the recipient's postoperative lung function. Traditionally, Date's formula, also called the segmental ratio, has used the number of lung segments to estimate the forced vital capacity (FVC) of grafts in LDLLT. To provide a more precise estimate of graft FVC, we calculated the volumes of the lower lobe and total lung using three-dimensional computed tomography (3D-CT) and the volume ratio between them. We calculated the volume ratio in 52 donors and tested the difference between the segmental volume ratios with a one-tailed t-test. We also calculated the predicted graft FVC in 21 LDLLTs using the segmental ratio pFVC(c) and the volume ratio pFVC(v), and then found the Pearson's correlation coefficients for both pFVC(c) and pFVC(v) with the recipients' actual FVC (rFVC) measured spirometrically 6 months after surgery. Significant differences were found between the segmental ratio and the average volume ratio for both sides (right, p=0.03;left, p=0.0003). Both pFVC(c) and pFVC(v) correlated significantly with rFVC at 6 months after surgery (p=0.007 and 0.006). Both the conventional and the volumetric methods provided FVC predictions that correlated significantly with measured postoperative FVC
Relation between Fractal Inhomogeneity and In/Nb-Arrangement in Pb(In1/2Nb1/2)O3
Relaxor ferroelectrics show substantial responses to electric fields. The key difference from normal ferroelectrics is a temperature-dependent inhomogeneous structure and its dynamics. The lead-based complex perovskite Pb(In1/2Nb1/2)O3 is an intriguing system in which the inhomogeneous structure can be controlled by thermal treatment. Herein, we report investigations of the phase transitions in single crystals of Pb(In1/2Nb1/2)O3 via changing the degree of randomness in which In and Nb occupy the B site of the ABO3 perovskite structure. We studied the dynamic properties of the structure using inelastic light scattering and the static properties using diffuse X-ray scattering. These properties depend on the degree of randomness with which the B site is occupied. When the distribution of occupied In/Nb sites is regular, the antiferroelectric phase is stabilised by a change in the collective transverse-acoustic wave, which suppresses long-range ferroelectric order and the growth of the inhomogeneous structure. However, when the B site is occupied randomly, a fractal structure grows as the temperature decreases below T*~475 K, and nanosized ferroelectric domains are produced by the percolation of self-similar and static polar nanoregions
Broadband inelastic light scattering of a relaxor ferroelectric 0.71Pb(Ni1/3Nb2/3)O3-0.29PbTiO3
Brillouin and Raman scatterings of a 0.71Pb(Ni1/3Nb2/3)O3-0.29PbTiO3 single crystal have been measured to investigate broadband inelastic spectra. The two different central peaks related to fast and slow relaxation processes have been observed separately. These two processes are attributed to the thermally activated switching of polarization in polar nanoregions. By the analysis of modified superparaelectric model, the activation energies of fast and slow relaxation processes are determined to be 3.66×103 and 4.31×102 K, respectively. The fast process with the lower activation energy probably originated from 180° switching, whereas the slow one with the higher energy from non-180° switching
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