Relazione PRIN Anno 2007 - Miglioramento delle prestazioni nanomeccaniche e della funzionalizzazione di superficie di cantilever, per una nuova classe di sensori di massa chimico-specifici

The functionalization of the cantilevers can be exploited to realize chemical-specific mass sensors. Silicon substrates have been functionalized with porphyrin and biphenyl molecules, and their properties have been investigated.I cantilever funzionalizzati possono essere utilizzati come sensori di massa chimico-specifici. Sono state studiate le propriet? di strati di porfirine e di bifenili su silicio

On the formation of blisters in annealed hydrogenated a-Si layers

Differently hydrogenated radio frequency-sputtered a-Si layers have been studied by infrared (IR) spectroscopy as a function of the annealing time at 350 Celsius with the aim to get a deeper understanding of the origin of blisters previously observed by us in a-Si/a-Ge multilayers prepared under the same conditions as the ones applied to the present a-Si layers. The H content varied between 10.8 and 17.6 at.% as measured by elastic recoil detection analysis. IR spectroscopy showed that the concentration of the clustered (Si-H)n groups and of the (Si-H2)n (n ≥ 1) polymers increased at the expense of the Si-H mono-hydrides with increasing annealing time, suggesting that there is a corresponding increase of the volume of micro-voids whose walls are assumed from literature to be decorated by the clustered mono-hydride groups and polymers. At the same time, an increase in the size of surface blisters was observed. Also, with increasing annealing time, the total concentration of bonded H of any type decreases, indicating that H is partially released from its bonds to Si. It is argued that the H released from the (Si-H)n complexes and polymers at the microvoid surfaces form molecular H2 inside the voids, whose size increases upon annealing because of the thermal expansion of the H2 gas, eventually producing plastic surface deformation in the shape of blisters

Exploiting magnetic properties of Fe doping in zirconia

In this study we explore, both from theoretical and experimental side, the effect of Fe doping in ZrO2 (ZrO2:Fe). By means of first principles simulation we study the magnetization density and the magnetic interaction between Fe atoms. We also consider how this is affected by the presence of oxygen vacancies and compare our findings with models based on impurity band and carrier mediated magnetic interaction. Experimentally thin films (~ 20 nm) of ZrO2:Fe at high doping concentration are grown by atomic layer deposition. We provide experimental evidence that Fe is uniformly distributed in the ZrO2 by transmission electron microscopy and energy dispersive X-ray mapping, while X-ray diffraction evidences the presence of the fluorite crystal structure. Alternating gradient force magnetometer measurements show magnetic signal at room temperature, however with low magnetic moment per atom. Results from experimental measures and theoretical simulations are compared.Comment: 8 pages, 9 figures. JEMS 201

Influence of hydrogen on the structural stability of annealed ultrathin Si/Ge amorphous layers

Semiconductor structures based on Si and Ge are generally submitted to hydrogenation because H passivates the dangling bonds of Si and Ge. By this way the devices prepared from those semiconductors, e.g., solar cells, have much better electrical properties. However, H stability is still a critical issue. In fact, there is wide evidence that H is very unstable against illumination as well as heat treatment. It has been seen that H out effuses from the samples under such treatments. As this causes unsaturation of the dangling bonds the electrical properties worsen significantly. In this work we will show that in the case of ultrathin Si/Ge amorphous layers the H thermal instability also affects the structural stability even up to the micrometric scale depending on the H content. Such type of structure can also be used to prepare SiGe alloys by mixing the layers with heat treatments. The samples were amorphous multilayers (MLs) of alternating ultrathin (3 nm) layers of Si and Ge deposited by sputtering on (100) oriented Si substrate. The total thickness of the MLs was 300 nm. The samples were hydrogenated by introducing H in the sputter chamber with flow rates varying from 0.8 to 6 ml/min. The MLs underwent different heat treatments, from the one at 350 ?C for 1 h up to the one at 250 ?C for 0.5 h + 450 ?C for 5 h. The samples were analysed by AFM, TEM, energy filtering TEM and Small-Angle X-Ray Diffraction (SAXRD). AFM showed that upon annealing the structure of the samples degrades with formation of surface bumps whose size increases by increasing the annealing temperature and/or time, for the same H content, or by increasing the H content for the same annealing conditions. For high H content and/or annealing conditions AFM showed that the bumps have blown up giving rise to craters. This suggests that H was released from its dangling bonds to Si and Ge and formed H bubbles in the MLs because of the energy supplied by the annealing. Additional energy for the break of the Si-H and Ge-H bonds could be the one supplied by the recombination of thermally generated carriers associated with the band gap fluctuations caused by the not uniform distribution of H in the MLs. The first sites of H accumulation are very likely nanocavities certainly present in the amorphous MLs. By TEM it has been seen that layer intermixing occurred which could be the first step of H bubbles formation. SAXRD measurements as well as TEM energy filtering maps for Si and Ge showed that Si and Ge interdiffusion took place in an asymmetric way as Si was seen to diffuse to the Ge layers whereas Ge did not diffuse to the Si layers. This might be due to the higher density of free dangling bonds in the Ge layers created by annealing because the binding energy of the Ge-H bond is smaller than the one of the Si-H bond

PRÁTICAS DE SAÚDE MENTAL NA ATENÇÃO BÁSICA SOB A ÓTICA DOS PROFISSIONAIS GESTORES

Objective: To describe mental health practices in primary care from the perspective of professionals. Method: Descriptive, qualitative research, from February to May 2019, through the application of a semi-structured questionnaire sent to professionals who directly serve mental health users in 24 municipalities and interview with a technician from a health region from Paraná. Data were analyzed according to Bardin's content analysis technique. Results: The following categories were identified: risk stratification as a practice in mental health care services; the work of professionals from the family health support center; networking and; therapeutic follow-up. Final considerations: The perceptions of professionals are heterogeneous, however there is consensus on the fragility of the PHC role in constituting an efficient and resolute gateway and risk stratification is often not performed.Objetivo: Describir las prácticas de salud mental en la atención primaria desde la perspectiva de los profesionales. Método: Investigación descriptiva, cualitativa, de febrero a mayo de 2019, mediante la aplicación de un cuestionario semiestructurado enviado a profesionales que atienden directamente a usuarios de salud mental en 24 municipios y entrevista con técnico de una región de salud de Paraná. Los datos se analizaron según la técnica de análisis de contenido de Bardin. Resultados: Se identificaron las siguientes categorías: estratificación de riesgo como práctica en los servicios de atención a la salud mental; el trabajo de los profesionales del centro de apoyo a la salud de la familia; trabajo en red y; seguimiento terapéutico. Consideraciones finales: Las percepciones de los profesionales son heterogéneas, sin embargo existe consenso sobre la fragilidad del rol de la APS para constituir una puerta de entrada eficiente y resolutiva y muchas veces no se realiza la estratificación del riesgo.Objetivo: descrever as práticas de saúde mental na atenção básica sob a ótica dos profissionais gestores. Método: pesquisa descritiva, qualitativa, realizada no período de fevereiro a maio de 2019, mediante aplicação de questionário semiestruturado enviado aos profissionais que atendem diretamente os usuários de saúde mental em 24 municípios e entrevista com um técnico de uma região de saúde do Paraná. Os dados foram analisados de acordo com a técnica de análise de conteúdo de Bardin. Resultados: foram identificadas as seguintes categorias: estratificação de risco como prática nos serviços de atenção em saúde mental; o trabalho dos profissionais do núcleo de apoio à saúde da família; o trabalho em rede; o acompanhamento terapêutico. Considerações finais: as percepções dos profissionais são heterogêneas, contudo há consenso sobre a fragilidade no papel da atenção primária em constituir uma porta de entrada eficiente e resolutiva e a estratificação de risco, muitas vezes, não é realizada. Descritores: Planejamento em Saúde. Pessoal de Saúde. Saúde Mental. Serviços de Saúde Mental. Assistência à Saúde Mental

Sixth Cranial Nerve Palsy and Craniocervical Junction Instability due to Metastatic Urothelial Bladder Carcinoma

Metastases involving the clivus and craniocervical junction (CCJ) are extremely rare. Skull base involvement can result in cranial nerve palsies, while an extensive CCJ involvement can lead to spinal instability. We describe an unusual case of clival and CCJ metastases presenting with VI cranial nerve palsy and neck pain secondary to CCJ instability from metastatic bladder urothelial carcinoma. The patient was first treated with an endoscopic endonasal approach to the clivus for decompression of the VI cranial nerve and then with occipitocervical fixation and fusion to treat CCJ instability. At the 6-month follow-up, the patient experienced complete recovery of VI cranial nerve palsy. To the best of our knowledge, the simultaneous involvement of the clivus and the CCJ due to metastatic bladder carcinoma has never been reported in the literature. Another peculiarity of this case was the presence of both VI cranial nerve deficit and spinal instability. For this reason, the choice of treatment and timing were challenging. In fact, in case of no neurological deficit and spinal stability, palliative chemo- and radiotherapy are usually indicated. In our patient, the presence of progressive diplopia due to VI cranial nerve palsy required an emergent surgical decompression. In this scenario, the extended endoscopic endonasal approach was chosen as a minimally invasive approach to decompress the VI cranial nerve. Posterior occipitocervical stabilization is highly effective in avoiding patient’s neck pain and spinal instability, representing the approach of choice

Role of interface and morphology in the magnetic behaviour of perpendicular thin films based on L10 FePt

FePt L10 ordered alloy is a promising material for high-density magnetic recording, since it allows the ferromagnetic stability in particles of few nanometers. Here we present our recent studies on the correlation between magnetic and morphological/interfacial properties of FePt -based thin films, nanostructures, and nano-composite bilayers. L10 FePt (001) epitaxial thin films with high structural quality were grown on (100) MgO by sputtering r.f., using the alternate-layer deposition method. By playing with growth temperature on the one hand and post-annealing temperature and time on the other, we have been able to finely control epitaxy, structural order, and morphology from 3D laterally confined structures to continuous film, with desired grain size. In particular we have been able to decrease grain size and to optimise magnetic properties (increase of anisotropy/coercivity ratio) at the same time, by post-annealing in situ [1]. Laterally confined magnetic structures were also obtained by focused ion beam (FIB). We have shown that for suitable Ga+ doses (1?1014 ion/cm2), it is possible to transform the L10 ordered phase to the A1 disordered one, without affecting morphology, giving rise to substantial modifications of magnetic properties from hard to soft. Perpendicular 2D magnetic patterns (dots, stripes) in a soft easy-plane matrix were realized in films of continuous morphology [2]. FePt L10 has also been exploited as the hard layer of nanostructured hard-soft nanocomposite bilayers. The exploitation of the exchange-coupling between hard and soft layers in exchange-coupled media represents a possible approach to overcome the so-called "recording trilemma" [3]. The samples were prepared by growing a magnetically soft Fe layer (2 and 3.5 nm) over a hard FePt(001) layer (10 nm). Three bilayers series have been grown based on FePt epitaxial layers with high degree of chemical order (S≥0.76) and different morphologies, corresponding to different interface characteristics. The resulting hard layer anisotropy is high (K>1?107 erg/cm3), and the coercivity is increased by the grains separation (from 1.7 to 3 T). In the Fe/FePt bilayers the coercivity HC is strongly reduced compared to the hard layer value (HC/HChard down to 0.37), indicating that high anisotropy perpendicular systems with moderate coercivity can be obtained [4]. Moreover, the control of the interface morphology allows to modify the magnetic regime at fixed Fe thickness (Rigid Magnet to Exchange-Spring), due to the nanoscale structure effect on the hard/soft coupling, and to tailor the hysteresis loop characteristics

High‐Density Sb2Te3 Nanopillars Arrays by Templated, Bottom‐Up MOCVD Growth

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