Thermal Stability of Ge<Subscript>2</Subscript>Sb<Subscript>2</Subscript>Te<Subscript>5</Subscript> in Contact with Ti and TiN

The thermal stability of a Ge₂Sb₂Te₅ chalcogenide layer in contact with titanium and titanium nitride metallic thin films has been investigated mainly using x-ray diffraction and elastic nuclear backscattering techniques. Without breaking vacuum, Ti and TiN have been deposited on Ge₂Sb₂Te₅ material using magnetron sputtering. Thermal treatments have been performed in a 10⁻⁷ mbar vacuum furnace. On annealing up to 450°C, the TiN metallic film does not interact with the chalcogenide film, but at the same time adhesion problems and instabilities in contact resistance arise. To improve the adhesion and eventually stabilize the contact resistance, an interfacial Ti layer has been considered. At 300°C, a TiTe₂ compound is formed by interacting with Te segregated from the Ge₂Sb₂Te₅ layer. At higher temperatures, the Ti layer decomposes the chalcogenide film, forming several compounds tentatively identified as GeTe, Ge₃Ti₅, Ge₅Ti₆, TiTe_2,, and Sb₂Te₃. It has been found that the properties of the Ge₂Sb₂Te₅ film can be retained by controlling the decomposition rate of the chalcogenide layer, which is achieved by providing a limited supply of Ti and/or by depositing a Te-rich Ge₂Sb₂Te₅ film.     

Advances in Infrared Spectroscopy of Catalytic Solid–Liquid Interfaces: The Case of Selective Alcohol Oxidation

Progress in the use of ATR-IR spectroscopy to improve the understanding of liquid-phase heterogeneous catalytic reactions is illustrated using the example of the oxidation of benzyl alcohol over Pd/Al₂O₃ and Bi–Pd/Al₂O₃. The in situ studies performed in both batch and continuous reactor cells provide rich information on the reaction pathway and important facets of the mechanism, such as the nature of active Pd sites and the effect of the Bi-promoter. The combination of CO site blocking prior to reaction and isotopic labeling suggests that alcohol dehydrogenation occurs uniformly over Pd nanoparticles, but only selected sites may allow desorption of the product benzaldehyde thus providing the required selectivity. Promotion of Pd/Al₂O₃ using bismuth produces infrared spectra free of adsorbed CO. This information demonstrates that Bi is deposited on selected adsorption sites (terraces rather than defects) and simultaneously confirms that open terraces favor product decomposition. Experiments performed in the continuous reactor cell using different catalyst film thickness show that reactions can be studied under kinetic or mass transfer limited conditions depending on catalyst film thickness. This allowed to study the alcohol oxidation under conditions of oxygen diffusion limitation, which are preferably applied in praxis in order to prevent catalyst deactivation by over-oxidation.     

Lipid Metabolism Is Dysregulated before,during and after Pregnancy in a Mouse Model of Gestational Diabetes

The aim of the current study was to test the hypothesis that maternal lipid metabolism was modulated during normal pregnancy and that these modulations are altered in gestational diabetes mellitus (GDM). We tested this hypothesis using an established mouse model of diet-induced obesity with pregnancy-associated loss of glucose tolerance and a novel lipid analysis tool, Lipid Traffic Analysis, that uses the temporal distribution of lipids to identify differences in the control of lipid metabolism through a time course. Our results suggest that the start of pregnancy is associated with several changes in lipid metabolism, including fewer variables associated with de novo lipogenesis and fewer PUFA-containing lipids in the circulation. Several of the changes in lipid metabolism in healthy pregnancies were less apparent or occurred later in dams who developed GDM. Some changes in maternal lipid metabolism in the obese-GDM group were so late as to only occur as the control dams’ systems began to switch back towards the non-pregnant state. These results demonstrate that lipid metabolism is modulated in healthy pregnancy and the timing of these changes is altered in GDM pregnancies. These findings raise important questions about how lipid metabolism contributes to changes in metabolism during healthy pregnancies. Furthermore, as alterations in the lipidome are present before the loss of glucose tolerance, they could contribute to the development of GDM mechanistically.     

Robot training of upper limb in multiple sclerosis: comparing protocols with or without manipulative task components

In this pilot study, we compared two protocols for robot-based rehabilitation of upper limb in multiple sclerosis (MS): a protocol involving reaching tasks (RT) requiring arm transport only and a protocol requiring both objects' reaching and manipulation (RMT). Twenty-two MS subjects were assigned to RT or RMT group. Both protocols consisted of eight sessions. During RT training, subjects moved the handle of a planar robotic manipulandum toward circular targets displayed on a screen. RMT protocol required patients to reach and manipulate real objects, by moving the robotic arm equipped with a handle which left the hand free for distal tasks. In both trainings, the robot generated resistive and perturbing forces. Subjects were evaluated with clinical and instrumental tests. The results confirmed that MS patients maintained the ability to adapt to the robot-generated forces and that the rate of motor learning increased across sessions. Robot-therapy significantly reduced arm tremor and improved arm kinematics and functional ability. Compared to RT, RMT protocol induced a significantly larger improvement in movements involving grasp (improvement in Grasp ARAT sub-score: RMT 77.4%, RT 29.5%, p=0.035) but not precision grip. Future studies are needed to evaluate if longer trainings and the use of robotic handles would significantly improve also fine manipulation.     

Preliminary Investigation on the Involvement of Cytoskeleton-Related Proteins,DAAM1 and PREP,in Human Testicular Disorders

Herein, for the first time, the potential relationships between the cytoskeleton-associated proteins DAAM1 and PREP with different testicular disorders, such as classic seminoma (CS), Leydig cell tumor (LCT), and Sertoli cell-only syndrome (SOS), were evaluated. Six CS, two LCT, and two SOS tissue samples were obtained during inguinal exploration in patients with a suspect testis tumor based on clinical examination and ultrasonography. DAAM1 and PREP protein levels and immunofluorescent localization were analyzed. An increased DAAM1 protein level in CS and SOS as compared to non-pathological (NP) tissue was observed, while LCT showed no significant differences. Conversely, PREP protein level increased in LCT, while it decreased in CS and SOS compared to NP tissue. These results were strongly supported by the immunofluorescence staining, revealing an altered localization and signal intensity of DAAM1 and PREP in the analyzed samples, highlighting a perturbed cytoarchitecture. Interestingly, in LCT spermatogonia, a specific DAAM1 nuclear localization was found, probably due to an enhanced testosterone production, as confirmed by the increased protein levels of steroidogenic enzymes. Finally, although further studies are needed to verify the involvement of other formins and microtubule-associated proteins, this report raised the opportunity to indicate DAAM1 and PREP as new potential markers, supporting the cytoskeleton dynamics changes occurring during normal and/or pathological cell differentiation.     

CFD model for tubular SOFC directly fed by biomass

The coupling between biomass gasification and Solid Oxide Fuel Cells can represent a sustainable and efficient system for electricity production. This work aims to develop a preliminary model for the operation of a tubular, electrolyte-supported fuel cell (SOFC) fed by a syngas mixture. The fuel required by the SOFC system is produced inside the energy generator box from an integrated biomass gasification system. This study stems from the European DB-SOFC project, that proposed the exploitation of the abundant biomasses deriving from agricultural residues for energetic purposes (as from olive oil and wine production). In this study, the main processes have been simulated to find a possible configuration to obtain a power value of 200 W. 25 cells were used in the model to produce the required power. The results showed that at 0.7 V it is possible to achieve 12.3 W, when the biomass gasification was integrated into the SOFC box, while it was possible to achieve 9.6 W when the system was fed by externally produced syngas.     

Submicron laser-textured vents for self-cleaning injection molds

Clogging of venting slots in injection molds is a common maintenance problem caused by the degradation and the accumulation of gaseous and volatiles by-products of polymer melting. In this work, the effect of laser-induced periodic surface structures on the self-cleaning properties of venting slots is investigated. The degradation of poly(ethylene terephthalate) (PET) over different surfaces is characterized by reproducing the mechanisms that occurs in mold cavities when the air is pushed through the venting channel. An imaging technique is developed for the quantification of the sediment that deposits on sample surfaces due to condensation of by-products of PET melting. The experimental results indicate that the use of a multiscale texture minimizes the deposition of residues on the vent surface reducing it from 17.2 to 3.1%. A linear dependency between contact angle and clogging ratio indicates the efficacy of the model that explains vent self-cleaning properties considering their wetting properties.     

Controlled Individual Skyrmion Nucleation at Artificial Defects Formed by Ion Irradiation

Magnetic skyrmions are particle‐like deformations in a magnetic texture. They have great potential as information carriers in spintronic devices because of their interesting topological properties and favorable motion under spin currents. A new method of nucleating skyrmions at nanoscale defect sites, created in a controlled manner with focused ion beam irradiation, in polycrystalline magnetic multilayer samples with an interfacial Dzyaloshinskii–Moriya interaction, is reported. This new method has three notable advantages: 1) localization of nucleation; 2) stability over a larger range of external field strengths, including stability at zero field; and 3) existence of skyrmions in material systems where, prior to defect fabrication, skyrmions were not previously obtained by field cycling. Additionally, it is observed that the size of defect nucleated skyrmions is uninfluenced by the defect itself—provided that the artificial defects are controlled to be smaller than the inherent skyrmion size. All of these characteristics are expected to be useful toward the goal of realizing a skyrmion‐based spintronic device. This phenomenon is studied with a range of transmission electron microscopy techniques to probe quantitatively the magnetic behavior at the defects with applied field and correlate this with the structural impact of the defects.