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AbstractA series of SnO2-Al2O3composite metal oxide supports with different Sn/Al atomic ratios were synthesized with co-precipitation method and used as supports for Pd to prepare catalysts for CO oxidation. The samples were characterized by N2adsorption-desorption, CO adsorption-desorption, X-ray Powder Diffraction (XRD), H2temperature programmed reduction (H2TPR), and X-ray photoelectron spectroscopy (XPS) techniques. It was found that Al3+can be introduced into the crystalline lattice of tetragonal rutile SnO2to effectively form solid solution structure. As a consequence, SnO2-Al2O3binary supports with significantly improved thermal stability, enlarged surface areas, enhanced texture structure and containing more active surface oxygen species can be obtained. SnAl73, a support with a Sn/Al atomic ratio of 7/3, was found to be the best support in this study due to its certain large surface area and the presence of suitable amount of reducible oxygen species. With this support, the two major reasons accounting for the activity, that is, Pd dispersion and strong metal support interaction (SMSI) between Pd and the support, is believed to be tuned optimally. Water vapor has reversible effect on the CO oxidation activity of Pd/SnAl73 catalyst, but which is mitigated evidently by the presence of SnO2. In addition, no any permanent deactivation occurs to Pd/SnAl73 catalyst during a 60 hours' test in the presence or absence of water vapor, indicating this optimized SnO2-Al2O3support has a strong potential to be applied in some practical processes for exhaust clean. In summary, SnO2-Al2O3composite metal oxides with suitable Sn/Al atomic ratios are better supports than individual Al2O3and SnO2, on which less amount of Pd could be used to achieve supported Pd catalysts with rival performance.

Magnetic resonance elastography (MRE) is a recently developed imaging technique that can directly visualize and quantitatively measure tissue elasticity.

BackgroundInflammatory myofibroblastic tumor (IMT) is a rare tumor of mesenchymal origin that commonly occurs in the lung. Because of its non-specific clinical and imaging features, IMT is often misdiagnosed as a malignant tumor. There have been few imaging reports on IMT of the head and neck.PurposeTo analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of inflammatory myofibroblastic tumors (IMTs) of the head and neck.Material and MethodsSix patients with IMTs of the head and neck confirmed by histopathologic examination were analyzed retrospectively.ResultsThe mean patient age was 40 years. The tumor locations in the six patients were as follows: left bridge of the nose (one), right infratemporal fossa (two), and left parotid gland (three). Three patients who underwent CT all had soft tissue masses or nodules and no calcification. Bridge of the nose tumor showed a homogeneous isodense nodule and mild homogeneous enhancement. Infratemporal fossa tumor showed a homogeneous low density mass and intermediate homogeneous enhancement. Left parotid gland tumor showed a heterogeneous, mostly low density mass, and intermediate heterogeneous enhancement. T1-weighted images of the parotid gland tumors were hypointense; the infratemporal fossa tumor was isointense. T2-weighted images were mildly hypointense and of mixed hypo- and isointensity in the two parotid gland tumors; the infratemporal fossa tumor was homogeneously mildly hypointense. Heterogeneous intermediate enhancement was demonstrated in one parotid gland and the infratemporal fossa patients and mild homogeneous enhancement in another parotid gland patient.ConclusionThe imaging features of IMTs of the head and neck are non-specific. An ill-defined, aggressive mass and variable enhancement on CT and MRI may suggest the diagnosis of IMT. IMT should be included in the differential diagnosis of regional tumors.

BackgroundPrevious studies have demonstrated that magnetic resonance imaging may be a method of choice to visualize transplanted pancreatic islets. However, contrast agents may interfere with microcirculation and affect graft function.PurposeTo evaluate the effects manganese-containing contrast media on regional blood flow and glucose tolerance.Material and MethodsAnesthetized rats were injected intravenously with MnCl2(10 µM/kg body weight) or Mn-DPDP (Teslascan™; 5 µM/kg body weight). Blood flow measurements were made with a microsphere technique 10 min later. In separate animals vascular arteriolar reactivity in isolated, perfused islets was examined. Furthermore, an intraperitoneal glucose tolerance test was performed in separate rats.ResultsGlucose tolerance was unaffected by both agents. No changes in regional blood flow were seen after administration of Mn-DPDP, except for an increase in arterial liver blood flow. MnCl2increased all blood flow values except that of the kidney. MnCl2, but not Mn-DPDP, caused a vasoconstriction in isolated rat islet arterioles but only at very high doses.ConclusionMn-DPDP administration does not affect glucose tolerance or regional blood flow, besides an increase in arterial hepatic blood flow, and may therefore be suitable for visualization of islets.