Effect of substrate polishing on the growth of graphene on 3C-SiC(111)/Si(111) by high temperature annealing.

We analyse the effects of substrate polishing and of the epilayer thickness on the quality of graphene layers grown by high temperature annealing on 3C-SiC(111)/Si(111) by scanning tunnelling microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, low energy electron diffraction and high resolution angle resolved photoemission spectroscopy. The results provide a comprehensive set of data confirming the superior quality of the graphene layers obtained on polished substrates, and the limitations of the growth obtained on unpolished surfaces.

99mTc-MIBI scintimammography using a dedicated nuclear mammograph.

UNLABELLED: This study reports on a prototype single-photon emission mammograph (SPEM) dedicated to 99mTc-hexakis-2-methoxyisobutile isonitrile (MIBI) scintimammography. Main technical features are reported together with physical performance. Preliminary patient data are also reported. METHODS: The SPEM detector head is composed of a CsI(T1) scintillating array coupled to a Hamamatsu R3292 position-sensitive photomultiplier tube with crossed-wire anode. The high-resolution collimator is 35-mm thick with a 1.7-mm hole diameter and a 0.2-mm septal thickness. The electronic acquisition system is composed of five integrated cards with computation based on high-speed programmable microprocessors. The readout electronics include correction maps for on-line energy correction and spatial uniformity. The small size of the detector head allows the use of mechanical breast compression to minimize detection distance and tissue scatter. After physical SPEM performance evaluation in vivo scintimammography was performed in 29 patients and was compared with a state-of-the-art Anger camera. RESULTS: The SPEM showed an intrinsic spatial resolution of 2 mm, an energy resolution of 23% FWHM at 122 keV and spatial uniformities of 18% (integral) and 13.5% (differential). The SPEM imaged one 0.4-cm carcinoma missed by the Anger camera and resolved as separate lumps an irregular focal uptake on the Anger camera image. The remaining cases yielded concordant results. CONCLUSION: The SPEM prototype presented in this study shows adequate physical characteristics for 99mTc-MIBI scintimammography.

[Cardiac involvement in HIV infection: a prospective, multicenter clinical and echocardiographic study]. / Interessamento cardiaco in corso di infezione da HIV: studio prospettico policentrico, clinico ed ecocardiografico.

Cardiac abnormalities are frequently reported in patients with acquired immunodeficiency syndrome (AIDS). Much less is known about the true prevalence of cardiac involvement in patients with human immunodeficiency virus (HIV) infection. We prospectively examined 138 consecutive patients with HIV infection including 41 with AIDS, 49 with AIDS-related complex (ARC), 32 with chronic lymphoadenopathy syndrome (LAS) and 16 with asymptomatic HIV infection. Sixty-one patients had opportunistic infection. The prevalence of cardiac involvement progressively increased from patients with HIV infections or LAS (4%) to ARC (14%) to AIDS (37%). "Major" echocardiographic abnormalities (dilated cardiomyopathy and/or infective endocarditis and/or severe pericardial effusion) were identified in 3 patients (2%), "minor" abnormalities (mild pericardial effusion, hypokinesis of the interventricular septum, mild dilatation of the left ventricle in 21 (15%). Electrocardiographic abnormalities unassociated with echo abnormalities or clinical problems were seen in other 11 patients. End diastolic left ventricular dimension (normalized for body surface area) was higher among AIDS respect to pre-AIDS patients (30.1 +/- 7.1 vs 27.6 +/- 7.5; p less than 0.01) and among patients with respect to patients without opportunistic infections (29.5 +/- 6.5 vs 27.5 +/- 2.4; p less than 0.05). Left ventricular shortening fraction was lower in the subgroup with and absolute CD4 lymphocyte count less than 100/mm3 (31 +/- 7 vs 34 +/- 5; p less than 0.055). In conclusion, in a large, unselected group of patients with HIV infection, echocardiogram discloses cardiac abnormalities in 17% of the cases; their clinical relevance is generally low but in selected patients cardiac tamponade and/or dilated cardiomyopathy (secondary to viral myocarditis) may cause death.(ABSTRACT TRUNCATED AT 250 WORDS)