CuO Nanoparticles and Microaggregates: An Experimental and Computational Study of Structure and Electronic Properties.

The link between morphology and properties is well-established in the nanoparticle literature. In this report, we show that different approaches in the synthesis of copper oxide can lead to nanoparticles (NPs) of different size and morphology. The structure and properties of the synthesized NPs are investigated with powder X-ray diffraction, scanning electron microscopy (SEM), and diffuse reflectance spectroscopy (DRS).

Observation of terahertz transition from Fano resonances to bound states in the continuum.

Bound states in the continuum (BIC) in metamaterials have recently attracted attention for their promising applications in photonics. Here, we investigate the transition from Fano resonances to BIC, at terahertz (THz) frequencies, of a one-dimensional photonic crystal slab made of rectangular dielectric rods. Simulations performed by an analytical exact solution of the Maxwell equations showed that symmetry-protected, high-quality factor (Q), BIC emerge at normal incidence.

Molecular origin of the two-step mechanism of gellan aggregation.

Among hydrocolloids, gellan is one of the most studied polysaccharides due to its ability to form mechanically stable gels. Despite its long-standing use, the gellan aggregation mechanism is still not understood because of the lack of atomistic information. Here, we fill this gap by developing a new gellan force field.

Terahertz waves dynamic diffusion in 3D printed structures.

Applications of metamaterials in the realization of efficient devices in the terahertz band have recently been considered to achieve wave deflection, focusing, amplitude manipulation and dynamical modulation. Terahertz metamaterials offer practical advantages since their structures have typical sizes of hundreds microns and are within the reach of current three-dimensional (3D) printing technologies. Here, we propose terahertz photonic structures composed of dielectric rods layers made of acrylonitrile styrene acrylate realized by low-cost, rapid, and versatile fused deposition modeling 3D-printing.

Gellan Gum Microgels as Effective Agents for a Rapid Cleaning of Paper.

Microgel particles have emerged in the past few years as a favorite model system for fundamental science and for innovative applications ranging from the industrial to biomedical fields. Despite their potentialities, no works so far have focused on the application of microgels for cultural heritage preservation. Here we show their first use for this purpose, focusing on wet paper cleaning.

Short- and Long-Term Effects of X-ray Synchrotron Radiation on Cotton Paper.

X-ray analytical techniques are increasingly being used to study manuscripts and works of art on paper, whether with laboratory equipment or synchrotron sources. However, it is difficult to anticipate the impact of X-ray photons on paper- and cellulose-based artifacts, particularly due to the large variety of their constituents and degradation levels, and the subsequent material multiscale heterogeneity. In this context, this work aims at developing an analytical approach to study the modifications in paper upon synchrotron radiation (SR) X-ray radiation using analytical techniques, which are fully complementary and highly sensitive, yet not frequently used together.

High-resolution multiparametric MRI of contemporary and waterlogged archaeological wood.

High-resolution NMR images on three different present-day wood samples and an archaeological wood specimen were presented and discussed. Although the spatial resolution is still low to perform dendrology for the exact identification of the wooden species, the T -spin-density weighted images exhibit contrasts that are in excellent agreement with optical histological images. On the other hand, T * and T -weighted images provide physiological information that is not obtainable by the usual light microscopic investigations.

NiO Pseudocapacitance and Optical Properties: Does The Shape Win?

In the present paper, we investigate the effects of alkali and operational temperature on NiO capacitive and optical properties. The NiO samples were prepared by a straightforward, surfactant-free hydrothermal synthesis, employing Ni(NO) and either urea or moderately sterically hindered triethylamine (TEA). The syntheses were followed by calcinations at either 400 or 600 °C.

Polarization-maintaining reflection-mode THz time-domain spectroscopy of a polyimide based ultra-thin narrow-band metamaterial absorber.

This paper reports the design, the microfabrication and the experimental characterization of an ultra-thin narrow-band metamaterial absorber at terahertz frequencies. The metamaterial device is composed of a highly flexible polyimide spacer included between a top electric ring resonator with a four-fold rotational symmetry and a bottom ground plane that avoids misalignment problems. Its performance has been experimentally demonstrated by a custom polarization-maintaining reflection-mode terahertz time-domain spectroscopy system properly designed in order to reach a collimated configuration of the terahertz beam.

The role of water in the degradation process of paper using H HR-MAS NMR spectroscopy.

The thermodynamic properties of water are essential for determining the corresponding properties of every biosystem it interacts with. Indeed, the comprehension of hydration mechanisms is fundamental for the understanding and the control of paper degradation pathways induced by natural or artificial aging. In fact, the interactions between water and cellulose at the accessible sites within the fibres' complex structure are responsible for the rupture of hydrogen bonds and the consequent swelling of the cellulose fibres and consumption of the amorphous regions.

Nanoscale analysis of degradation processes of cellulose fibers.

Mapping the morphological and nano-mechanical properties of cellulose fibers within paper sheets or textile products at the nano-scale level by using atomic force microscopy is a challenging task due to the huge surface level variation of these materials. However this task is fundamental for applications in forensic or cultural heritage sciences and for the industrial characterization of materials. In order to correlate between nano-mechanical properties and local nanometer scale morphology of different layers of cellulose fibers, a new strategy to prepare samples of isolated cellulose fibers was designed.

Molecular degradation of ancient documents revealed by 1H HR-MAS NMR spectroscopy.

For centuries mankind has stored its knowledge on paper, a remarkable biomaterial made of natural cellulose fibers. However, spontaneous cellulose degradation phenomena weaken and discolorate paper over time. The detailed knowledge of products arising from cellulose degradation is essential in understanding deterioration pathways and in improving durability of cultural heritage.

Docosahexaenoic acid reverts resistance to UV-induced apoptosis in human keratinocytes: involvement of COX-2 and HuR.

The dramatic increase in the incidence of nonmelanoma skin cancer over the last decades has been related to the augmented exposure to ultraviolet (UV) radiation (UVR). It is known that apoptosis is induced as a protective mechanism after the acute irradiation of keratinocytes, whereas apoptotic resistance and carcinogenesis may follow the chronic exposure to UVR. We found that not all the human keratinocytes lines studied underwent apoptosis following acute exposure to UVR (10-60 mJ/cm(2)).

Ristocetin-induced self-aggregation of von Willebrand factor.

Von Willebrand factor (VWF) is a large multimeric adhesive glycoprotein, with complex roles in thrombosis and hemostasis, present in circulating blood and in secretory granules of endothelial cells and platelets. High shear stress triggers conformational changes responsible for both binding to the platelet receptor glycoprotein GpIb and its self-association, thus supporting the formation of platelet plug under flow. Ristocetin also promotes the interaction of VWF with GpIb and is able to induce platelet aggregation, and thus is largely used to mimic this effect in vitro.

Mechanical properties of zona pellucida hardening.

We have investigated the changes in the mechanical properties of the zona pellucida (ZP), a multilayer glycoprotein coat that surrounds mammalian eggs, that occur after the maturation and fertilization process of the bovine oocyte by using atomic force spectroscopy. The response of the ZP to mechanical stress has been recovered according to a modified Hertz model. ZP of immature oocytes shows a pure elastic behavior.

Modifications in solvent clusters embedded along the fibers of a cellulose polymer network cause paper degradation.

Plants, algae, and their derivatives (paper, textiles, etc.) are complex systems that are chiefly composed of a web of cellulose fibers. The arrangement of solvents within the polymeric structure is of great importance since cellulose degradation is strongly influenced by water accessibility and external agents.

Growth, viability, adhesion potential, and fibronectin expression in fibroblasts cultured on zirconia or feldspatic ceramics in vitro.

Zirconia, a biomaterial widely used in dentistry, has recently attracted much attention for its mechanical strength and toughness. Previously, its lack of mutagenic and carcinogenic power was reported. We describe here other essential aspects to be taken into account to define in vitro the biocompatibility of a material: the growth rate, viability, and adhesion capacity of normal stabilized cells growing on it.

Modifications of the mesoscopic structure of cellulose in paper degradation.

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose's supramolecular structure, which allows access to degradation agents, in ancient and modern samples.