Caveolin-1 and mitochondrial alterations in regenerating rat liver

The liver has a remarkable ability to regenerate after partial hepatectomy (PH), although the factors governing such ability are still poorly understood. During the prereplicative phase of the regeneration, ultrastructural alterations of periportal hepatocytes were seen, including mitochondrial swelling, abnormal accumulation of lipids, and myelin figures which could lead to the formation of lipid droplets. As it has been hypothesized that caveolin-1 is involved in lipidogenesis and in mitochondrial homeostasis, we aimed to study the subcellular distribution of caveolin-1 in hepatocytes at an early stage following PH. Liver samples were processed for light and electron microscopy at 0 h, 24 h, and 96 h after PH. The expression and subcellular distribution of caveolin-1 was assessed by immunohistochemical and immunocytochemical techniques. Following PH, at 24 h, membranes of altered mitochondria of periportal hepatocytes exhibited significant decrease of caveolin-1 expression compared with control. Myelin figures showing high expression of caveolin-1 were also seen. At 96 h, hepatocytes became ultrastructurally similar to the control liver, and the expression of caveolin-1 on mitochondria showed a moderate increase compared with 24 h after PH. Decrease of expression of caveolin-1 in the altered liver mitochondrial membranes at 24 h following PH, and the high expression of caveolin-1 observed on myelin figures, suggests involvement of caveolin-1 is in both mitochondrial homeostasis and lipidogenesis. Addressing the role played by caveolin-1 during liver regeneration might disclose additional features of mitochondrial homeostasis and lipidogenesis during frequent metabolic liver diseases.     

Quiescent and shear-induced non-isothermal crystallization of isotactic polypropylene-based nanocomposites

The paper reports a study of the effect of the addition of clay nanoparticles on melt rheology, phase structure, and non-isothermal crystallization process of isotactic polypropylene/hydrogenated oligocyclopentadiene (iPP/HOCP) system in quiescent conditions by DSC and under shear applied at different temperatures by SAXS. For both crystallization conditions, the addition of clay and/or HOCP shifts always the crystallization onset to lower values with respect to iPP. These results can be attributed to the diluent effect of HOCP that causes a decrease in the rate of nucleation and grow of the crystals, to the presence of segregated non-crystallizable phases/particles which hinder the transport of macromolecules chains toward the growing nuclei, and to the formation of beta iPP crystals and in the case of shear-induced crystallization to the presence of HPS which seems to reduce, mainly at low T _s, the amount of oriented polymer crystals, which are nuclei for the crystallization. At a given composition, the crystallization temperatures related at the crystallization under shear are always higher that those obtained by quiescent crystallization supporting the idea that the presence of extended chains in these samples act as nucleating agents favoring the crystallization process of iPP.     

A new rigorous model for high-resolution satellite imagery orientation: application to EROS A and QuickBird

The correct georeferencing of remote sensing imagery is a fundamental task for orthoimages, digital elevation models (DEMs)/digital surface models (DSMs) generation and 3D feature/object extraction. In this article we focus on the georeferencing of pushbroom sensors imagery, in particular single images collected by EROS A and QuickBird satellites, with a rigorous model that is based on the collinearity equations. The model, implemented in the software SISAR (Software per Immagini Satellitari ad Alta Risoluzione), reconstructs the orbital segment during image acquisition through the Keplerian orbital parameters, the sensor attitude, the internal orientation and additional self-calibration parameters. With respect to the estimation procedure, in order to avoid possible instabilities due to high correlations among some parameters leading to design matrix pseudo-singularity, singular value decomposition (SVD) and QR decomposition are used to select the estimable parameters and finally to solve the extended linearized collinearity equations system in the least square (LS) sense.

To test the effectiveness of the new model, SISAR results are compared with the rigorous model implemented in the well-known commercial software OrthoEngine 10.0 (PCI Geomatics, ON, Canada). In this article six images are concerned (two from EROS A and four from QuickBird), showing that SISAR performances are at the level of the OrthoEngine ones.     

Rational approximations of spectral densities based on the Alpha divergence

We approximate a given rational spectral density by one that is consistent with prescribed second-order statistics. Such an approximation is obtained by selecting the spectral density having minimum “distance” from under the constraint corresponding to imposing the given second-order statistics. We analyze the structure of the optimal solutions as the minimized “distance” varies in the Alpha divergence family. We show that the corresponding approximation problem leads to a family of rational solutions. Secondly, such a family contains the solution which generalizes the Kullback–Leibler solution proposed by Georgiou and Lindquist in 2003. Finally, numerical simulations suggest that this family contains solutions close to the non-rational solution given by the principle of minimum discrimination information.     

Synthesis and characterization of UV-curable nanocellulose/ZnO/AlN acrylic flexible films: Thermal,dynamic mechanical and piezoelectric response

This work is aimed at fabricating nanocomposites based on zinc oxide (ZnO) nanostructures and nanocellulose dispersed in a UV-cured acrylic matrix (EC) for application as functional coatings for self-powered applications. Morphological, thermal, and dynamic mechanical properties of the nanocomposites were characterized by X-Ray diffractometry (XRD), scanning electron microscopy, and differential scanning calorimetry. The piezoelectric behavior was evaluated in terms of root mean square (RMS) open circuit voltage, at different accelerations applied to cantilever beams. The generated voltage was correlated with ZnO nanostructures morphology, aluminum nitride film integration on the beam and proof mass insertion at the tip. Nitride layer increased the RMS voltage from 1 to 2.4 mV up to 3.9 mV (using ZnO nanoflowers). As confirmed by XRD analyses, the incorporation of ZnO nanostructures into the acrylic matrix favored an ordered structural arrangement of the deposited AlN layer, hence improving the piezoelectric response of the resulting nanocomposites. With proof mass insertion, the output voltage was further increased, reaching 4.5 mV for the AlN-coated system containing ZnO nanoflowers.     

Fully Transparent Nanocomposite Coating with an Amorphous Alumina Matrix and Exceptional Wear and Scratch Resistance

This study presents a method for high temperature stabilization of amorphous alumina. The strain‐induced stabilization is obtained by dispersion of rigid globular polycarbosilane macromolecules within an alumina matrix. The alumina matrix remains amorphous even at 1200 °C. This study confirms the chemical composition of the coating with an advanced chemical depth‐profile analysis and shows its nanostructure by transmission electron microscopy. Based on this amorphous nanocomposite, a new facile and inexpensive coating for mechanical protection of glass surfaces is further developed. The nanocomposite coating is characterized by a full optical transparency and exceptional tribological characteristics. The wear resistance exceeds that of the current advanced ion‐exchanged boroaluminosilicate glass by a factor of 25–35 whereas its scratch resistance is exceeded by more than an order of magnitude.     

Effects of Velocity Gradients and Secondary Flow on the Dispersion of Solutes in a Meandering Channel

Two contrasting mechanisms, created by channel curvature which strongly affect longitudinal dispersion of solutes in rivers are examined. In natural channels the large cross-sectional variability of the primary velocity component tends to increase longitudinal dispersion by providing a large difference between adjacent fast and slow moving zones of fluid. By contrast secondary circulation tends to decrease longitudinal dispersion by enhancing transverse mixing. A series of tests have been carried out in a very large flume containing a meandering water-formed sand bed channel to measure the longitudinal dispersion coefficient at various locations around a meander. These experimental observations are compared with experimental data obtained from meandering channels with smooth, fixed sides and regular cross-sectional shapes. All the data has been compared against predictions from two current modeling approaches. Finally, the significance of the two competing mechanisms in curved channels is discussed with regard to their relative influence on longitudinal mixing.