Cerebellar tumour-like aggregate of glycosaminoglycans in a MPS IIIB patient: a case report.

INTRODUCTION: Mucopolysaccharidosis (MPS) IIIB is a lysosomal disorder in which a deficiency in α-N-acetylglucosaminidase impairs the degradation of heparan sulphate, which accumulates in tissues causing multiple organs dysfunction. This disease is associated with significant central nervous system (CNS) abnormalities, but a presentation with a tumour-like lesion has never been reported so far. CLINICAL PRESENTATION: The present report describes the case of a 5-year-old girl suffering from MPS IIIB who developed a cerebellar lesion with evident mass effect. She underwent surgery with a subsequent notable improvement of her clinical picture. Surprisingly, the pathological analysis revealed the lesion to have the typical MPS features. CONCLUSION: This case would describe a neglected possible presentation of MPS IIIB with a lesion mimicking a neoplasm, which could even be successfully treated with surgery.

In Silico Shear and Intramural Stresses are Linked to Aortic Valve Morphology in Dilated Ascending Aorta.

OBJECTIVE/BACKGROUND: The development of ascending aortic dilatation in patients with bicuspid aortic valve (BAV) is highly variable, and this makes surgical decision strategies particularly challenging. The purpose of this study was to identify new predictors, other than the well established aortic size, that may help to stratify the risk of aortic dilatation in BAV patients. METHODS: Using fluid-structure interaction analysis, both haemodynamic and structural parameters exerted on the ascending aortic wall of patients with either BAV (n = 21) or tricuspid aortic valve (TAV; n = 13) with comparable age and aortic diameter (42.7 ± 5.3 mm for BAV and 45.4 ± 10.0 mm for TAV) were compared. BAV phenotypes were stratified according to the leaflet fusion pattern and aortic shape. RESULTS: Systolic wall shear stress (WSS) of BAV patients was higher than TAV patients at the sinotubular junction (6.8 ± 3.3 N/m2 for BAV and 3.9 ± 1.3 N/m2 for TAV; p = .006) and mid-ascending aorta (9.8 ± 3.3 N/m2 for BAV and 7.1 ± 2.3 N/m2 for TAV; p = .040). A statistically significant difference in BAV versus TAV was also observed for the intramural stress along the ascending aorta (e.g., 2.54 × 105 ± 0.32 × 105 N/m2 for BAV and 2.04 × 105 ± 0.34 × 105 N/m2 for TAV; p < .001) and pressure index (0.329 ± 0.107 for BAV and 0.223 ± 0.139 for TAV; p = .030). Differences in the BAV phenotypes (i.e., BAV type 1 vs. BAV type 2) and aortopathy (i.e., isolated tubular vs. aortic root dilatations) were associated with asymmetric WSS distributions in the right anterior aortic wall and right posterior aortic wall, respectively. CONCLUSION: These findings suggest that valve mediated haemodynamic and structural parameters may be used to identify which regions of aortic wall are at greater stress and enable the development of a personalised approach for the diagnosis and management of aortic dilatation beyond traditional guidelines.

Interplay of Surface and Dirac Plasmons in Topological Insulators: The Case of Bi_{2}Se_{3}.

We have investigated plasmonic excitations at the surface of Bi_{2}Se_{3}(0001) via high-resolution electron energy loss spectroscopy. For low parallel momentum transfer q_{∥}, the loss spectrum shows a distinctive feature peaked at 104 meV. This mode varies weakly with q_{∥}. The behavior of its intensity as a function of primary energy and scattering angle indicates that it is a surface plasmon. At larger momenta (q_{∥}~0.04 Å^{-1}), an additional peak, attributed to the Dirac plasmon, becomes clearly defined in the loss spectrum. Momentum-resolved loss spectra provide evidence of the mutual interaction between the surface plasmon and the Dirac plasmon of Bi_{2}Se_{3}. The proposed theoretical model accounting for the coexistence of three-dimensional doping electrons and two-dimensional Dirac fermions accurately represents the experimental observations. The results reveal novel routes for engineering plasmonic devices based on topological insulators.

Alkali-induced hydrogenation of epitaxial graphene by water splitting at 100 K.

The coadsorption of potassium with water at 100 K on graphene/Pt(111) has been studied by high-resolution electron energy loss spectroscopy. The adsorption of alkali metals induces water splitting and the formation of C-H and C-OH groups. Such finding is of great interest for tailoring graphene-Pt electro-catalysts. Furthermore, the alkali-promoted dissociation of water molecules offers the possibility to attain a partial hydrogenation of the graphene sheet even at low temperature.

The adsorption and co-adsorption of oxygen and carbon monoxide on Pt3Ni(111): a vibrational study.

High-resolution electron energy loss spectroscopy has been used to investigate the adsorption and co-adsorption of oxygen and CO on the Pt(3)Ni(111) surface. For the sake of comparison, similar measurements have also been performed on the Pt(111) surface. We find that CO adsorbs at the same manner on both surfaces. By contrast, significant differences between the two surfaces exist concerning the adsorption of O and the co-adsorption of O with CO.

A photogrammetric method for target monitoring inside the MEG II detector.

An automatic target monitoring method based on photographs taken by a CMOS photo-camera has been developed for the MEG II detector. The technique could be adapted for other fixed-target experiments requiring good knowledge of their target position to avoid biases and systematic errors in measuring the trajectories of the outcoming particles. A CMOS-based, high resolution, high radiation tolerant, and high magnetic field resistant photo-camera was mounted inside the MEG II detector at the Paul Scherrer Institute (Switzerland). MEG II is used to search for lepton flavor violation in muon decays. The photogrammetric method's challenges, affecting measurements of low momentum particles' tracks, are the high magnetic field of the spectrometer, high radiation levels, tight space constraints, and the need to limit the material budget in the tracking volume. The camera is focused on the dot pattern drawn on the thin MEG II target, about 1 m away from the detector endcaps where the photo-camera is placed. Target movements and deformations are monitored by comparing images of the dots taken at various times during the measurement. The images are acquired with a Raspberry board and analyzed using custom software. Global alignment to the spectrometer is guaranteed by corner cubes placed on the target support. As a result, the target monitoring fulfills the needs of the experiment.

CO-promoted formation of the alkali-oxygen bond on Ni(111).

High-resolution electron energy loss spectroscopy was used to study the coadsorption of alkali metals (Na, K) and oxygen on clean and CO-modified Ni(111) surfaces. We unambiguously show that on an alkali-precovered surface, the alkali-O bond was not formed upon O(2) exposure. On the contrary, the alkali-O bond was readily observed by exposing to O(2) the Ni(111) surface precovered with an alkali+CO phase. This enhanced oxidation rate of alkali metals in the presence of CO molecules was ascribed to the short-range CO-induced modification of the electronic charge of alkali-metal adatoms.

Plasmonic modes confined in nanoscale thin silver films deposited onto metallic substrates.

Collective electronic excitations in nanoscale thin Ag layers adsorbed on Cu(111) and Ni(111) at room temperature have been investigated by high-resolution electron energy loss spectroscopy. Surface plasmon was found to be confined within grains on Ag thin films on Cu(111) nanostructured in islands. Annealing removed surface plasmon confinement and induced a negative linear term of the dispersion relation. On the other hand, on flat thin films on Ni(111) the dispersion of Ag surface plasmon is fully quadratic. Landau damping processes of the plasmonic excitation were found to be dependent on the growth mode. Ag multipole surface plasmon at 7.7 eV was observed only under stringent kinematic conditions enhancing surface sensitivity.

Collective excitations in nanoscale thin alkali films: Na/Cu(111).

The relationship between electron quantum confinement and the energy dispersion of the surface plasmon in nanoscale thin Na layers adsorbed on Cu(111) at room temperature have been studied by high resolution electron energy loss spectroscopy. Screening effects due to electron quantum confinement occurring in this system cause the lowering of the surface plasmon frequency and, moreover, make the energy range of its dispersion curve larger than in thick alkali films. Landau damping of the plasma excitation was unexpectedly very efficient at small momenta. The dispersion curve of the Na surface plasmon was found to depend on the primary electron beam energy. Multipole surface plasmon at 4.70 eV was observed only for higher impinging energies.

Comparative vibrational study on alkali coadsorption with CO and O on Ni(111) and Cu(111).

High-resolution electron energy loss spectroscopy was used to investigate alkali (Na, K) coadsorption with CO and O on Cu(111) and Ni(111). Measurements provided new insights in these systems. A CO-induced weakening of the alkali-substrate bond was revealed on both substrates. The effect is more pronounced for the Na+CO/Ni(111) system. Submonolayers of alkalis were found to promote the preferential population of the subsurface site for O/Cu(111) but not for O/Ni(111).

Alkali-promoted CO dissociation on Cu(111) and Ni(111) at room temperature.

The coadsorption of alkalis (K, Na) and CO on Cu(111) was investigated by high-resolution electron energy loss spectroscopy. Measurements performed at room temperature showed that CO adsorption is partially dissociative on a potassium-precovered Cu(111) surface and fully dissociative for Na/Cu(111). Carbon monoxide molecules occupy adsorption sites directly adjacent to those of alkali adatoms, as suggested by the absence of a threshold alkali precoverage for CO dissociation. On the contrary, for alkali+CO/Ni(111) a threshold alkali precoverage for CO dissociation was found to exist.

When plasmonics meets membrane technology.

In this review, we present the applications of thermoplasmonics in membrane processes. We discuss the influence of the heat capacity of the solvent, the amount of plasmonic nanoparticles in the membrane, the intensity of the light source and the transmembrane flow rate on the increase of permeability. Remarkably, thermoplasmonic effects do not involve any noticeable loss of membrane rejection. Herein, we consider application feasibilities, including application fields, requirements of feed, alternatives of light sources, promising thermoplasmonic nanoparticles and scaling up issues.

The influence of chemical reactivity of surface defects on ambient-stable InSe-based nanodevices.

We demonstrate that, in contrast to most two-dimensional materials, ultrathin flakes of InSe are stable under ambient conditions. Despite their ambient stability, InSe-based nanodevices show an environmental p-type doping, suppressed by capping InSe with hexagonal boron nitride. By means of transport experiments, density functional theory and vibrational spectroscopy, we attribute the p-type doping assumed by uncapped InSe under an ambient atmosphere to the decomposition of water at Se vacancies. We have estimated the site-dependent adsorption energy of O2, N2, H2O, CO and CO2 on InSe. A stable adsorption is found only for the case of H2O, with a charge transfer of only 0.01 electrons per water molecule.

[Acute pericarditis in pregnancy. Report of a case]. / Pericardite acuta in gravidanza. Descrizione di un caso.

In this study the authors describe a case of acute pericarditis occurring at 26 weeks' gestation in a woman affected by Wolff-Parkinson-White Syndrome and with a history of Hodgkin's Lymphoma and autoimmune hypothyroidism. The patient was first admitted to the 4th Medical Pathology Unit of the University of Florence, where moderate pericardic effusion with no evidence of heart tamponade was documented by ultrasound scan. Subsequently the patient was cared for on outpatient basis at the Centre of Perinatal Medicine of the Department of Obstetrics and Gynaecology of the University of Florence. Since all examinations and tests aimed at defining the etiology of pericardial effusion were negative, an idiopathic acute pericarditis was diagnosed. The patient was given prednisone at a dose of 75 mg per day; owing to episodes of paroxystic atrial fibrillation, propaphenon was also administered intravenously to treat acute episodes and orally as prophylaxis. The patient underwent close control of both heart function (by means of ultrasound scans of the heart and dynamic EKG) and pregnancy (blood tests, ultrasound scans and Doppler velocimetry). At 36.5 weeks' gestation a healthy fetus was spontaneously delivered. Three months after delivery, the patient underwent an ultrasound scan that demonstrated the complete reabsorption of the effusion.

[The problem of lymph nodes in malignant epithelial tumors of the parotid gland]. / Il problema linfonodale nei tumori epiteliali maligni della parotide.

Cervical lymph-node treatment in parotid gland epithelial malignancies is still debated. According to Literature, three different strategies (surgery, radiotherapy, "wait and see") have all been proposed theoretically, particularly when dealing with N0 cases. The present study was designed to evaluate the results of different lymphonode treatment strategies in 57 parotid gland carcinomas followed at the ENT Clinic of the University of Ferrara. The most frequent hystological patterns appeared to be the adenoidcystic carcinoma (33.3%) and the mucoepidermoid tumor (21.1%). Total parotidectomy was the treatment of choice in all cases. Ipsilateral neck dissection was performed in 14 cases (24.5%), 5 cases being N0. In 27 patients (47.4%) postsurgical radiotherapy was applied: in 7 cases on T and in 20 on both T and N.T recurrences were 7, while those of N and of both T and N were respectively 2 and 2. No occult metastases were found in N0 dissected patients. The results obtained led the Authors to the following conclusions: -neck dissection is fundamental in treatment of clinical adenopathies in any parotid gland malignancy: -postsurgical radiotherapy on the neck is the treatment of choice in all N0 carcinomas except in cases of acinic cell and mucoepidermoid carcinomas, where a "wait and see" policy seems to be more suitable.

[Dentinal lesions caused by the use of endodontic posts]. / Lesioni dentinali causate dall'impiego di alcuni endoposts.

An endodontic treatment has been effected on 36 extracted teeth, using drills; certain endodontic posts presently on the market have been successively inserted inside 18 teeth: Flexipost (Essential Dental System); Parapost Plus (Whaledent); dentatus (Dentatus). The teeth have been sectionized and watched through a photomicroscope to check an eventual presence of dentinal damages.

Evidence of composite plasmon­phonon modes in the electronic response of epitaxial graphene.

The electronic response of quasi-freestanding graphene on Pt(111) has been measured by high-resolution electron energy loss spectroscopy. Loss spectra reveal the existence of three distinct excitations: a dispersing feature due to the ordinary sheet plasmon and two dispersionless modes at 0.2 and 0.5­0.6 eV. The latter two features are assigned to the coupled plasmon­phonon excitation and to an interface plasmon, respectively. The complex interactions of plasmons with other particles have significant fundamental and practical implications on the electronic response of graphene and their knowledge is essential for tailoring upcoming graphene-based plasmonic devices.

Interplay between single-particle and plasmonic excitations in the electronic response of thin Ag films.

High-resolution electron energy loss spectroscopy is used to study the electronic properties of thin Ag layers on Ni(111). In addition to the ordinary surface plasmon at 3.8 eV, we observe a broad feature at 7-8 eV, whose nature is investigated as a function of scattering geometry and primary electron beam energy. Loss measurements unambiguously indicate that this mode has spectral components from both free-electron Ag plasmonic excitations (free-electron surface plasmons and multipole plasmons) and single-particle transitions.