In this paper, the ability of chitosan film to remove dyestuff from wastewater was evaluated for environmental applications, using three commercial direct azo dyes. Two chitosan films were adopted: the standard one prepared following a well-known procedure to form it, and a novel one, with a weakly acidic character. Moreover, to improve the adsorption process, the hydrophobic character of the films was investigated. The pH of the dye solutions was also changed, showing an excellent ability in dye removal at pH 12. The films were characterized by means of spectroscopic and morphologic methods to better understand the nature of interactions between dyes and chitosan chains. Swelling ratio measurements were also performed. All analyses suggest that all dyes showed a strong affinity to chitosan polymer chains, with the presence of extended hydrogen bonds and Van der Waals forces perturbing the chitosan network. Interestingly, very good results were obtained in recycling experiments related to the dyeing capacities of chitosan blended films in the presence of textiles. An ecofriendly application is thus presented in this paper.

The paper reveals a dual-band electrochromic device capable of selectively controlling the transmitted sunlight in the visible and near-infrared regions. It exploits the peculiar spectro-electrochemical features of vanadium-modified titanium oxide colloidal nanocrystals, which exhibit a distinctive electrochromic response at visible wavelengths upon the application of a small cathodic potential. They have been used as an active electrode in a sandwich cell in combination with a nanocrystalline tungsten oxide layer, which indeed allows selective control over the incoming near-infrared radiation at low applied potentials, until turning into a deep blue colored coating at higher potentials. These two coatings have been conveniently combined to realize an electrochromic device capable of separately operating over four different optical regimes, namely, fully transparent, VIS blocking, NIR blocking, and VIS + NIR blocking. Great benefits are anticipated in the field of glazing elements for buildings and transportation, where the solution proposed here may pave the way for the implementation of a novel class of "zero-energy" smart windows that self-adapt to both external climatic conditions and interior visual and thermal comfort requirements.

N-functionalization of 5,6-dihydroxyindole with a hydrophilic triethyleneglycol (TEG) chain provides access to a new class of water-soluble eumelanin-like materials with relatively high dielectric constant and polyelectrolyte behaviour, reflecting enhanced charge transport by in-depth incorporation of hydration networks.

Nucleophosmin (NPM1) is the most frequently mutated gene in Acute Myeloid Leukemia (AML) patients and mutations lead to its aberrant cytoplasmatic accumulation in leukemic cells. Its C-terminal domain (CTD) is endowed with a globular structure consisting of a three-helix bundle in the wild type form that is disrupted by AML mutations. Our recent results demonstrate, unexpectedly and unequivocally, that regions of the CTD of NPM1 are prone to aggregate to amyloid states. Here we present novel studies, at solution as well as fibrillar states of a nonapeptide covering the 264-272 region of NPM1: this small fragment is the most amyloidogenic stretch of the entire protein and its conformational and aggregation properties were investigated through Circular Dichroism, Fluorescence spectroscopies, amyloid seeding assay (ASA), isothermal titration calorimetry (ITC) and electrospray ionization (ESI) mass analyses. Structural features of fibrils were investigated by means of Scanning Electron Microscopy (SEM) and Wide-Angle X-ray Scattering (WAXS). This study deepens the amyloid fibrillization process of a short stretch of the CTD likely involved in the propagative mechanism for NPMc+ cytoplasmatic accumulation in leukemogenesis.

Phenylalanine-based nanostructures have attracted the attention of the material science community for their functional properties. These properties strongly depend on the hierarchic organization of the nanostructure that in turn can be finely tuned by punctual chemical modifications of the building blocks. Herein, we investigate how the partial or the complete replacement of the Phe residues in PEG(8)-(Phe)(6) (PEG(8)-F-6) with tyrosines to generate PEG(8)-(Phe-Tyr)(3) (PEG(8)-(FY)3) or PEG(8)-(Tyr)(6) (PEG(8)-Y6) affects the structural/functional properties of the nanomaterial formed by the parental compound. Moreover, the effect of the PEG derivatization was evaluated through the characterization of the peptides without the PEG moiety (Tyr)(6) (Y6) and (Phe-Tyr)(3) ((FY)3). Both PEG(8)-Y6 and PEG(8)-(FY)3 can self-assemble in water at micromolar concentrations in beta-sheet-rich nano structures. However, WAXS diffraction patterns of these compounds present significant differences. PEG(8)-(FY)3 shows a 2D WAXS oriented fiber diffraction profile characterized by the concomitant presence of a 4.7 angstrom meridional and a 12.5 angstrom equatorial reflection that are generally associated with cross-beta structure. On the other hand, the pattern of PEG(8)-Y6 is characterized by the presence of circles typically observed in the presence of PEG crystallization. Molecular modeling and dynamics provide an atomic structural model of the peptide spine of these compounds that is in good agreement with WAXS experimental data. Gelation phenomenon was only detected for PEG(8)-(FY)3 above a concentration of 1.0 wt% as confirmed by storage (G' approximate to 100 Pa) and loss (G '' approximate to 28 Pa) moduli in rheological studies. The cell viability on CHO cells of this soft hydrogel was certified to be 90% after 24 hours of incubation.

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

A new type of nanomaterial has been developed as antibacterial additive for food packaging applications.This nanocomposite is composed of copper nanoparticles embedded in polylactic acid, combining the antibacterial properties of copper nanoparticles with the biodegradability of the polymer matrix. Metal nanoparticles have been synthesised by means of laser ablation, a rising and easy route to prepare nanostructures without any capping agent in a liquid environment. As prepared, nanoparticle suspensions have been easily mixed to a polymer solution. The resulting hybrid solutions have been deposited by drop casting, thus obtaining self-standing antibacterial packages. All samples have been characterized by UV-Vis spectroscopy, X-ray photoelectron spectroscopy and electro-thermal atomic absorption spectroscopy. Ion release data have been matched with bioactivity tests performed by Japanese Industrial Standard (JIS) method (JIS Z 2801:2000) against Pseudomonas spp., a very common Gram-negative microbial group able to proliferate in processed food.

The ability of peptides to self-assemble represents a valuable tool for the development of biomaterialsof biotechnological and/or biomedical interest. Diphenylalanine homodimer (FF) and its analogues areamong the most promising systems in this field. The longest Phe-based building block hithertocharacterized is pentaphenylalanine (F5). We studied the aggregation propensity and the structural/morphological features of assemblies of zwitterionic hexaphenylalanine H+-F6-O and of three variantscharacterized by different charged states of the terminal ends (Ac-F6-Amide, H+-F6-Amide and Ac-F6-O).As previously observed for PEGylated hexaphenylalanine (PEG8-F6), all F6 variants show a strong tendencyto form b-rich assemblies in which the structural motif is constituted by antiparallel b-strands in thecross-b framework. Extensive replica exchange molecular dynamics simulations carried out on a pairs ofF6 peptides indicate that the antiparallel b-structure of the final assemblies is likely dictated by thepreferred association modes of the individual chains in the very early stages of the aggregation process.Our data suggest that even very small F6 peptides are properly pre-organized and prone to the build-upof the final assembly.

In this chapter, we will focus on a specific X-ray-based technique among those employed in surface science and which is especially suitable for the study of self-assembled nanocrystals: Grazing Incidence Small Angle X-ray Scattering (GISAXS). We will first introduce the main field of investigation considered herein, with basic notions of X-ray scattering from surfaces, and then address basic concepts about GISAXS. Finally, we will describe a few relevant examples of studies, of nanostructured architectures, through ex situ and in situ experiments of grazing incidence X-ray scattering. This manuscript is focused on the former, showing that they can be performed by using laboratory instruments. In situ investigations still need synchrotron radiation sources in most cases; therefore, only a few examples selected from the literature are reported here, for the sake of completeness. The experiments described are mainly performed in the small angle range, providing information on the size and shape of nanocrystals, together with their spatial arrangement. Both 2D and 3D architectures are considered. In particular, GISAXS measurements of 2D superlattices of nano-octapods, performed both at a third generation synchrotron beamline and with a table-top set-up, are compared; the employed table-top set-up is described in a dedicated paragraph. Further examples of grazing incidence studies as performed by the authors with a table-top set-up are reported: a GISAXS study of 3D iron oxide nanocrystal superlattices, showing the importance of modelling in order to obtain structural information from data; a combined small/wide angle scattering (GISAXS/GIWAXS) study of 3D PbS nanocrystal superlattices; and a GIWAXS study of P3HT nanofibres, showing how the ordering at the molecular and atomic length scales can be obtained by exploring different angular ranges in the same grazing incidence geometry. Finally, selected examples of in situ GISAXS studies, performed with synchrotron radiation sources, are described.

Inorganic nanocrystals (NCs) based nanovectors offer the potential for new and innovative drug delivery systems for a targeted transport of drugs towards tissues affected by most aggressive disease including cancer. Diagnostic and therapeutic applications require, for both in-vitro and in-vivo investigation, the determination of the maximum cellular dose of these nanovectors [1] that is also mandatory for any regulatory approval [2]. Accurate determination of the nanovector concentration is not a trivial issue and currently there is a lack of experimental methods recognized as general and reliable [3]. In this work, we propose an approach for the determination of the concentration of a solid lipid nanoparticle (SLN) nanovector encapsulating photoactive copper sulfide (Cu2-xS) NCs characterized by a tunable localized surface plasmon resonance (LSPR) in the biological transparent near-infrared (NIR) spectral region for photothermal therapy. Here, Cu2-xS NCs with a narrow size distribution and an intense LSPR in the second biological window have been synthesized by hot injection method and they have been encapsulated into SLN prepared by a hot homogenization technique using a mixture of lipids, triglycerides and phospholipids. A calculation method based on Mie-Drude theory using as input data resulting from spectroscopic and dimensional investigation for the Cu2-xS NCs and NCs containing SLNs has been successfully implemented and applied for the determination of the nanovector concentration. The results are in agreement with experimental data and the proposed approach hold a great potential for determining the concentration of plasmonic NCs based nanovectors.

The development of green and scalable syntheses for the preparation of size- A nd shape-controlled metal nanocrystals is of high interest in many areas, including catalysis, electrocatalysis, nanomedicine, and electronics. In this work, a new synthetic approach based on the synergistic action of physical parameters and reagents produces size-tunable octahedral Pt nanocrystals, without the use of catalyst-poisoning reagents and/or difficult-to-remove coatings. The synthesis requires sodium citrate, ascorbic acid, and fine control of the reduction rate in aqueous environment. Pt octahedral nanocrystals with particle size as low as 7 nm and highly developed {111} facets have been achieved, as demonstrated by transmission electron microscopy, X-ray diffraction, and electrochemical methods. The absence of sticky molecules together with the high quality of the surface makes these nanocrystals ideal candidates in electrocatalysis. Notably, 7 nm bismuth-decorated octahedral nanocrystals exhibit superior performance for the electrooxidation of formic acid in terms of both specific and mass activities.

Recent developments in laser joining show the applicability of spectral analysis of the plasma plume emission to monitor and control the quality of weld. The analysis of the complete spectra makes it possible to measure specific emission lines which reveal information about the welding process. The subsequent estimation of the electron temperature can be correlated with the quality of the corresponding weld seam. A typical quality parameter, for laser welds of stainless steel, is the achieved penetration depth of the weld. Furthermore adequate gas shielding of the welds has to be provided to avoid seam oxidation . In this paper monitoring and real-time control of the penetration depth during laser welding is demonstrated. Optical emissions in the range of 400nm and 560nm are collected by a fast spectrometer. The sensor data are used to determine the weld quality of overlap welds in AISI 304 stainless steel sheets performed both with CW Nd:YAG and CO2 lasers. A PI-controller adjusts the laser power aiming at a constant penetration. Optical inspection of the weld surface and microscopic analysis of weld cross sections were used to verify the results obtained with the proposed closed-loop system of spectroscopic sensor and controller.

In this paper we describe a novel spectroscopic closed loop control system capable of stabilizing the penetration depth during laser welding processes by controlling the laser power. Our novel approach is to analyze the optical emission from the laser generated plasma plume above the keyhole, to calculate its electron temperature as a process-monitoring signal. Laser power has been controlled by using a quantitative relationship between the penetration depth and the plasma electron temperature. The sensor is able to correlate in real time the difference between the measured electron temperature and its reference value for the requested penetration depth. Accordingly the closed loop system adjusts the power, thus maintaining the penetration depth.

In this study we evaluated an efficient microwave-solvothermal method to synthesize effective visible-light photocatalists based on the use of anatase TiO2 nanorods. The nanocrystals were obtained by hydrolysis of titanium tetraisopropoxide (TTIP) in the presence of benzyl alcohol at 210 C. The method was effective and produced TiO2 nanocrystals in the anatase phase with a rapid kinetics of crystallization. A significant size control was obtained tuning the TTIP to oleic acid molar ratio. High volumetric yield and reduced energy costs were achieved. All synthesized TiO2 nanocrystals showed a high photoactivity in comparison with commercial P25 titania, as they could degrade faster and completely Rhodamine B dye in solution under visible-light irradiation. The nanocrystals were characterized in detail by X-ray diffraction, low- and high-resolution transmission electron microscopy, microRaman and FT-IR spectroscopy. A distorted anatase structure due to oxygen vacancies was identified as being at the origin of the introduction of new energy levels into the anatase band gap, which probably promoted the visible-light photoactivity.

Very recently we proposed novel di- and tetra-phenylalanine peptides derivatized with gadolinium complexes as potentials supramolecular diagnostic agents for applications in MRI (Magnetic Resonance Imaging). It was observed that in very short FF dipeptide building blocks, the propensity to aggregate decreases significantly after modification with bulky moiety such as Gd-complexes, thus limiting their potential as CAs. We hypothesized that the replacement of the Phe side chain with more extended aromatic groups could improve the self-assembling. Here we describe the synthesis, structural and relaxometric behavior of a novel water soluble self-assembled peptide CA based on 2-naphthylalanine (2Nal). The peptide conjugate Gd-DOTA-L-6-(2Nal)(2) is able to self-assemble in long fibrillary nanostructures in water solution (up to 1.0 mg/mL). CD and FTIR spectroscopies indicate a beta sheet secondary structure with an antiparallel orientation of single strands. All data are in good agreement with WAXS and SAXS characterizations that show the typical "cross-beta pattern" for fibrils at the solid state. Molecular modeling indicates the three-dimensional structure of the peptide spine of aggregates is essentially constituted by extended beta-sheet motifs stabilized by hydrogen bonds and hydrophobic interactions. The high relaxivity of nanoaggregates (12.3 mM(-1) s(-1) at 20 MHz) and their capability to encapsulate doxorubicin suggest their potential application as supramolecular theranostic agents.

We report a very effective synthetic approach to achieve the in situ growth, directly at the surface of single walled carbon nanotubes, of shape controlled anatase TiO2 nanocrystals, either as nanorods or nanospheres, by simply tuning the ratio between reactants. Remarkably, the obtained SWCNTs/TiO2 heterostructures result dispersible in organic solvents, leading to optically clear dispersions. The photocatalytic activity of the SWCNTs/TiO2 heterostructures, compared with bare TiO2 nanorods or nanospheres demonstrates a significant enhancement. In particular, SWCNTs/TiO2 heterostructures demonstrates an enhancement of reaction rate up to 3 times with respect to the commercially available standard TiO2 powder (TiO2 P25) under UV light and up to 2 times under visible light.

We demonstrate that a non-invasive sensing technique based on optical feedback interferometry is capable to instantaneously measure the ablation front displacement and the removal rate during ultrafast laser percussion drilling of metallic plates. The sawtooth-like modulation of the interferometric signal out of the detecting sensor has been analyzed to reveal the time dependence of the removal depth with sub-micrometric resolution. Various dynamic factors related to the influence of laser pulse duration and peak energy have been assessed by in-situ spatial- and time-dependent characterization all through the ablation process. The importance of realtime measurement of the ablation rate is crucial to improve the basic understanding of ultrafast lasermaterial interactions. Moreover, the detection system results high-sensitive, compact, and easily integrable in most industrial workstations, enabling the development of on-line control to improve the ablation efficiency and the quality of laser micromachining processes.

The recent development of ultrafast laser ablation technology in precision micromachining has dramatically increased the demand for reliable and real-time detection systems to characterize the material removal process. In particular, the laser percussion drilling of metals is lacking of non-invasive techniques able to monitor into the depth the spatial- and time-dependent evolution all through the ablation process. To understand the physical interaction between bulk material and high-energy light beam, accurate in-situ measurements of process parameters such as the penetration depth and the removal rate are crucial. We report on direct real time measurements of the ablation front displacement and the removal rate during ultrafast laser percussion drilling of metals by implementing a contactless sensing technique based on optical feedback interferometry. High aspect ratio micro-holes were drilled onto steel plates with different thermal properties (AISI 1095 and AISI 301) and Aluminum samples using 120-ps/110-kHz pulses delivered by a microchip laser fiber amplifier. Percussion drilling experiments have been performed by coaxially aligning the diode laser probe beam with the ablating laser. The displacement of the penetration front was instantaneously measured during the process with a resolution of 0.41 ?m by analyzing the sawtooth-like induced modulation of the interferometric signal out of the detector system.

The aim of this work was to investigate the structural features of type I collagen isoforms and collagen-based films at atomic and molecular scales, in order to evaluate whether and to what extent different protocols of slurry synthesis may change the protein structure and the final properties of the developed scaffolds. Wide Angle X-ray Scattering data on raw materials demonstrated the preferential orientation of collagen molecules in equine tendon-derived collagens, while randomly oriented molecules were found in bovine skin collagens, together with a lower crystalline degree, analyzed by the assessment of FWHM (Full Width at Half Maximum), and a certain degree of salt contamination. WAXS and FT-IR (Fourier Transform Infrared) analyses on bovine collagen-based films, showed that mechanical homogenization of slurry in acidic solution was the treatment ensuring a high content of super-organization of collagen into triple helices and a high crystalline domain into the material. In vitro tests on rat Schwannoma cells showed that Schwann cell differentiation into myelinating cells was dependent on the specific collagen film being used, and was found to be stimulated in case of homogenization-treated samples. Finally DHT/EDC crosslinking treatment was shown to affect mechanical stiffness of films depending on collagen source and processing conditions.

The increasing demand of piezoelectric energyharvesters for wearable and implantable applications requiresbiocompatible materials and careful structural device design, payingspecial attention to the conformability characteristics, properlytailored to scavenge continuously electrical energy even from thetiniest body movements. This paper provides a comprehensive studyon a flexible and biocompatible aluminum nitride (AlN) energyharvester based on a new alternative fabrication approach, exploiting athin polyimide (PI) substrate, prepared by spin coating of precursorssolution. This strategy allows manufacturing substrates with adjustablethickness to meet conformability requirements. The device isbased on a piezoelectric AlN thin film, sputtered directly onto the softPI substrate, without poling/annealing processes and patterned bysimple and low cost microfabrication technologies. AlN active layer,grown on soft substrate, exhibits good morphological and structural properties with roughness root mean squared (Rrms) of 6.35nm, columnar texture and (002) c-axis orientation. Additionally, piezoelectric characterization has been performed and theextracted piezoelectric coefficient value of AlN thin film resulted to be 4.93 ± 0.09 pm/V. The fabricated flexible AlN energyharvester generates an output peak-to-peak voltage of ~1.4 V and a peak-to-peak current up to 1.6 ?A, under periodicaldeformation, corresponding to a current density of 2.1 ?A/cm2, and providing a maximum generated power of 1.57 ?W underoptimal resistive load. Furthermore, the AlN energy harvester exhibits high elasticity and resistance to mechanical fatigue. Highquality AlN piezoelectric layers on elastic substrates with tunable thicknesses pave the way for the development of astraightforward technological platform for wearable/implantable energy harvesters and biomechanical sensors.

Short peptides or single amino acids are interesting building blocks for hydrogels fabrication, frequently used as extracellular matrix-mimicking scaffolds for cell growth in tissue engineering. The combination of two or more peptide hydrogelators could allow the obtaining of different materials exhibiting new architectures, tunable mechanical properties, high stability and improved biofunctionality. Here we report on the synthesis, formulation and multi-scale characterization of peptidebased mixed hydrogels formed by the low molecular weight Fmoc-FF (N?-fluorenylmethyloxycarbonyl diphenylalanine) hydrogelator and of the PEG8-(FY)3 hexapeptide, containing three repetitions of Phe-Tyr motif and a PEG moiety at its Nterminus. Mixed hydrogels were also prepared replacing PEG8-(FY)3 with its analogue (FY)3, without the PEG moiety. Rheology analysis confirmed the improved mechanical features of the multicomponent gels prepared at two different ratios (2/1 or 1/1, v/v). However, the presence of the hydrophilic PEG polymeric moiety causes a slowing down of the gel kineticformation (from 42 to 18 minutes) and a decrease of the gel rigidity (G' from 9 to 6 kPa). Preliminary in vitro biocompatibility and cell adhesion assays performed on Chinese Hamster Ovarian (CHO) suggest a potential employ of these multicomponent hydrogels as exogenous scaffold materials for tissue engineering.

The engineering of electrochemically active films based on structurally and geometrically controlled transitionmetaloxide nanocrystals holds promise for the development of a new generation of energy-efficient dynamicwindows that may enable a spectrally selective control of sunlight transmission over the near-infrared regime.Herein, the different spectro-electrochemical signatures of two sets of engineered nanotextured electrodes madeof distinct anisotropic-shaped tungsten oxide building blocks are comparatively investigated. The electrodeswere fabricated starting from corresponding one-dimensional colloidal nanocrystals, namely solid and longitudinallycarved nanorods, respectively, which featured identical crystal phase and lattice orientation, butexposed two distinct space-filled volume structures with subtly different lattice parameters and nonequivalenttypes of accessible surfaces. The shape of nanocrystalline building blocks greatly impacted on the fundamentalelectrochemical charge-storage mechanisms and, hence on the electrochromic response of these electrodes, dueto concomitant bulk and surface-structure effects that could not be entirely traced to mere differences in surfaceto-volume ratio. Electrodes made of carved nanorods accommodated more than 80% of the total charge throughsurface-capacitance mechanisms. This unique prerogative was ultimately demonstrated to enable an outstandingspectral selectivity as well as an extremely efficient dynamic modulation of the optical transmittance at nearinfraredfrequencies (~ 80% in the range 700-1600 nm).

Organic capped Au nanoparticles (NPs) and PbS quantum dots (QDs), synthesized with high control on size and size distribution, were used as building blocks for fabricating solid crystals by solvent evaporation. The superlattice formation process for the two types of nano-objects was investigated as a function of concentration by means of electron microscopy and X-ray techniques. The effect of building block composition, size, geometry, and concentration and the role of the organic coordinating molecules was related to the degree of order in the superlattices. A convenient combination of different complementary X-ray techniques, namely in situ and ex situ GISAXS and GIWAXS, allowed elucidating the most reliable signatures of the superlattices at various stages of the self-assembly process, since their early stage of formation and up to few months of aging. Significantly different assembly behaviour was assessed for the two types of NPs, clearly explained on the basis of their chemical composition, ultimately reflecting on the assembling process and on the final structure characteristics.

Semiconductor/metal nanocomposites based on anatase TiO2 nanoparticles and Au nanorods (TiO2/AuNRs) were prepared by means of a co-precipitation method and subsequently calcinated at increasing temperature (from 250° to 650°C) obtaining up to 20 grams of catalysts. The structure and the morphology of the obtained nanocomposite material were comprehensively characterized by means of electron microscopy (SEM and TEM) and X-ray diffraction techniques. The photocatalytic performance of the TiO2/AuNRs nanocomposites was investigated as a function of the calcination temperature in experiment of degradation of water pollutants under both UV and UV-Vis irradiation, Photocatalytic experiments under UV irradiation were performed by monitoring spectrophotometrically the decolouration of a target compound (methylene blue, MB) in aqueous solution. UV-Visible light irradiation was, instead, used for testing the photocatalytic removal of an antibiotic molecule, Nalidixic acid, by monitoring the degradation process by HPLC-MS analysis. Interestingly, TiO2/AuNRs calcined at 450°C was up to 2.5 and 3.2 times faster than TiO2P25 Evonik, that is a commercially available reference material, in the photocatalytic degradation of the Methylene Blue and the Nalidixic Acid, under UV and visible light, respectively. The same nanocomposite material showed a photocatalytic degradation rate for the two target compounds up to 13 times faster than the bare TiO2-based catalysts.The obtained results are explained on the basis of the structure and morphology of the nanocomposites, that could be tuned according to the preparative conditions. The role played by the plasmonic domain in the heterostructured materials, either under UV and UV-Visible illumination, is also highlighted and discussed.The overall results indicate that the high photoactivity of TiO2/AuNRs in the visible range can be profitably exploited in photocatalytic applications, thanks also to the scalability of the proposed synthetic route, thus ultimately envisaging potential innovative solution for environmental remediation.

Despite the growing literature about diphenylalanine-based peptide materials, it still remains a challenge to delineate the theoretical insight into peptide nanostructureformation and the structural features that could permit materials with enhanced properties to be engineered. Herein, we report the synthesis of a novel peptide building blockcomposed of six phenylalanine residues and eight PEG units, PEG8-F6. This aromatic peptide self-assembles in water in stable and well-ordered nanostructures with optoelectronic properties. A variety of techniques, such as fluorescence, FTIR, CD, DLS, SEM, SAXS, and WAXS allowed us to correlate the photoluminescence properties of the self-assembled nanostructures with the structural organization of the peptide building block at the micro- and nanoscale. Finally, a model of hexaphenylalanine in aqueous solution by molecular dynamics simulations is presented to suggest structural and energetic factors controlling the formation of nanostructures.

The replacement of diseased tissues with biological substitutes with suitablebiomechanical properties is one of the most important goal in tissue engineering. Collagenrepresents a satisfactory choice for scaffolds. Unfortunately, the lack of elasticity represents arestriction to a wide use of collagen for several applications. In this work, we studied theeffect of human elastin-like polypeptide (HELP) as hybrid collagen-elastin matrices. Inparticular, we studied the biomechanical properties of collagen/HELP scaffolds ...

We report on an experimental study of the incubation effect during laser ablation of stainless steel with fs- and ps-pulses at high repetition rates. Ablation thresholds for multiple pulses N have been estimated. As expected, the ablation threshold decreases with N due to damage accumulation. The related incubation coefficient has been determined at different repetition rates, from 50-kHz to 1-MHz and two pulse durations: 650-fs and 10-ps. Results show that the incubation effect is lower for fs-pulses below 600 kHz. At higher repetition rates incubation is more pronounced regardless of the pulse duration, probably due to heat accumulation. © 2013 The Authors.

Nucleophosmin (NPM1) is a multifunctional protein involved in a variety of biological processes including the pathogenesis of several human malignancies and is the most frequently mutated gene in Acute Myeloid Leukemia (AML). To deepen the role of protein regions in its biological activities, lately we reported on the structural behavior of dissected C-terminal domain (CTD) helical fragments. Unexpectedly the H2 (residues 264-277) and H3 AML-mutated regions showed a remarkable tendency to form amyloid-like assemblies with fibrillar morphology and beta-sheet structure that resulted toxic when exposed to human neuroblastoma cells. More recently NPM1 was found to be highly expressed and toxic in neurons of mouse models of Huntington's disease (HD). Here we investigate the role of each residue in the beta-strand aggregation process of H2 region of NPM1 by performing a systematic alanine scan of its sequence and structural and kinetic analyses of aggregation of derived peptides by means of Circular Dichorism (CD) and Thioflavin T (Th-T) assay. These solution state investigations pointed out the crucial role exerted by the basic amyloidogenic stretch of H2 (264-271) and to shed light on the initial and main interactions involved in fibril formation we performed studies on fibrils deriving from the related Ala peptides through the analysis of fibrils with birefringence of polarized optical microscopy and wide-angle X-ray scattering (WAXS). This analysis suggested that the presence of branched Ile(269) conferred preferential packing patterns that, instead, appeared geometrically hampered by the aromatic side-chain of Phe(268). Present investigations could be useful to deepen the knowledge of AML molecular mechanisms and the role of cytoplasmatic aggregates of NPM1c+.

Bovine cornea was studied with scanning small-angle X-ray scattering (SAXS) microscopy, by using both synchrotron radiation and a microfocus laboratory source. A combination of statistical (adaptive binning and canonical correlation analysis) and crystallographic (pair distribution function analysis) approaches allowed inspection of the collagen lateral packing of the supramolecular structure. Results reveal (i) a decrease of the interfibrillar distance and of the shell thickness around the fibrils from the periphery to the center of the cornea, (ii) a uniform fibril diameter across the explored area, and (iii) a distorted quasi-hexagonal arrangement of the collagen fibrils. The results are in agreement with existing literature. The overlap between laboratory and synchrotron-radiation data opens new perspectives for further studies on collagen-based/engineered tissues by the SAXS microscopy technique at laboratory-scale facilities.Bovine cornea was studied with scanning small-angle X-ray scattering microscopy, by using both synchrotron radiation and a microfocus laboratory source. The supramolecular structure of the collagen fibers is explored thanks to the combination of statistical (adaptive binning and canonical correlation analysis) and crystallographic (pair distribution function analysis) approaches.

For both fundamental study of biological processes and early diagnosis of diseases, information about nanoscale changes in tissue and cell structure is crucial. Nowadays, almost all currently known nanoscopy methods rely upon the contrast created by fluorescent stains attached to the object or molecule of interest. This causes limitations due to the impact of the label on the object and its environment, as well as its applicability in vivo, particularly in humans. In this paper, a new label-free approach to visualize small structure with nano-sensitivity to structural alterations is introduced. Numerically synthesized profiles of the axial spatial frequencies are used to probe the structure within areas whose size can be beyond the diffraction resolution limit. Thereafter, nanoscale structural alterations within such areas can be visualized and objects, including biological ones, can be investigated with sub-wavelength resolution, in vivo, in their natural environment. Some preliminary results, including numerical simulations and experiments, which demonstrate the nano-sensitivity and super-resolution ability of our approach, are presented.

We studied the laser ablation dynamics of steel in the thermal regime both experimentally and theoretically. The real-time monitoring of the process shows that the ablation rate depends on laser energy density and ambient pressure during the exposure time. We demonstrated that the ablation efficiency can be enhanced when the pressure is reduced with respect to the atmospheric pressure for a given laser fluence, reaching an upper limit despite of high-vacuum conditions. An analytical model based on the Hertz-Knudsen law reproduces all the experimental results.

Direct real-time measurements of the penetration depth during laser micromachining has been demonstrated by developing a novel ablation sensor based on laser diode feedback interferometry. Percussion drilling experiments have been performed by focusing a 120-ps pulsed fiber laser onto metallic targets with different thermal conductivity. In-situ monitoring of the material removal rate was achieved by coaxially aligning the beam probe with the ablating laser. The displacement of the ablation front was revealed with sub-micrometric resolution by analyzing the sawtooth-like induced modulation of the interferometric signal out of the detector system.

An efficient microwave-assisted synthesis of TiO2:(B) nanorods, using titanium tetraisopropoxide (TTIP), benzyl alcohol as the solvent, together with boric acid and oleic acid as the additive reagents, has been developed. Chemical modification of TTIP by oleic acid was demonstrated as a rational strategy to tune the shape of TiO2 nanocrystals toward nanorod formation. The differently-shaped TiO2:(B) nanocrystals were characterized in detail by transmission electron microscopy (TEM), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and nitrogen absorption-desorption. Oleic acid coordinated on the nanocrystal surface was removed by the reduction of its carboxyl group, and the photocatalytic activity of bare TiO2 nanocrystals, under visible light irradiation, was also evaluated. The synthesized TiO2 anatase nanorods exhibited a good photoactivity and completely degraded Rhodamine B solution within three hours.

Novel photosensitizing film based on the natural hybrid polymer Chitosan/2-hydroxy-propyl-b-Cyclodextrin(CH/CD) is synthesized introducing Chlorophyll a (CH/CD/Chla) as a photoactive agent forpossible application in antimicrobial photodynamic therapy (PDT). The polymer absorbs visible light, inturn able to generate reactive oxygen species (ROS) and, therefore it can be used as environmentalfriendly and biodegradable polymeric photosensitizer (PS). The modified film is characterized by meansof different spectroscopic, calorimetric, diffraction techniques and microscopic imaging methodsincluding time-resolved absorption spectroscopy. UVeVis, FTIR-ATR and X-ray Photoelectron Spectroscopy(XPS) analyses suggest that Chla shows a strong affinity toward Chitosan introducing interactionswith amino groups present on the polymer chains. Nanosecond laser flash photolysis technique providesevidence for the population of the excited triplet state of Chla. Photogeneration of singlet oxygen isdemonstrated by both direct detection by using infrared luminescence spectroscopy and chemicalmethods based on the use of suitable traps. Scanning Electron Microscopy (SEM), Atomic Force Microscopy(AFM) and Differential Scanning Calorimetry (DSC) analyses confirm also the occurrence ofstructural changes both on the film surface and within the film layer induced by the insertion of thepigment. Moreover, X-ray Diffraction data (XRD) shows the existence of an amorphous phase for thechitosan films in all the compared conditions.

The photocatalytic degradation of pollutants is a key technological application for nanomaterials. Ourwork aims at developing a multifunctional nanocrystalline heterostructure based on TiO2nanorods,FexOyand Ag nanoparticles (NPs), TiO2NRs/FexOy/Ag, integrating in one nanostructure a visible lightphotoactive moiety (TiO2NRs/Ag) and a magnetic domain (FexOy), in order to address the photoactivityunder visible light and the possibility of recovery and reuse the photocatalyst. The synthesis was carriedby preparing first the TiO2NRs/FexOybased heterostructure and then growing Ag NPs with control on size.The resulting multidomain structures were characterized by FTIR and absorption spectroscopy, TEM andSEM microscopy, EDS and XRD analysis. The influence of the Ag NP domain and of its size on the photoac-tivity of the TiO2NRs/FexOy/Ag nanostructures under visible light were investigated in the photocatalyticdegradation of the Nalidixic Acid, an antibiotic used as a model compound representative of recalci-trant pollutants. In the presence of the Ag domain a significant increase of the photoactivity with respectto TiO2NRs/FexOyheterostructures and to the commercially available TiO2P25 was observed. Such anenhanced photocatalytic efficiency was found dependent on the size of the Ag domain and explainedtaking into account the plasmonic properties and the different possible photoactivation mechanisms.

Recent developments in the exploitation of transparent conductive oxide nanocrystals paved the way to the realization of a new class of electrochemical systems capable of selectively shielding the infrared heat loads carried by sunlight and prospected the blooming of a key enabling technology to be implemented in the next generation of "zero-energy" building envelopes. Here we report the fabrication of a set of electrochromic devices embodying an engineered nanostructured electrode made by high aspect-ratio tungsten oxide nanorods, which allow for selectively and dynamically controlling sunlight transmission over the near-infrared to visible range. Varying the intensity of applied voltage makes the spectral response of the device change across three different optical regimes, namely fully transparent, near-infrared only blocking and both visible and near-infrared blocking. It is demonstrated that the degree of reversible modulation of the thermal radiation entering the glazing element can approach a remarkable 85%, accompanied by only a modest reduction in the luminous transmittance.

Two different nanosized TiO2-based catalysts supported onto glass with tailored photocatalytic propertiesupon irradiation by UV light were successfully employed for the degradation of nalidixid acid, awidely diffused antibacterial agent of environmental relevance known to be non-biodegradable. Anataserod-like TiO2 nanocrystals (TiO2NRs) and a semiconductor oxide-noble metal nanocomposite TiO2 NRs/Ag nanoparticles (NPs), synthesized by colloidal chemistry routes, were cast onto glass slide andemployed as photocatalysts. A commercially available catalyst (TiO2 P25), also immobilized onto a glassslide, was used as a reference material. It was found that both TiO2 NRs/Ag NPs composite and TiO2 NRsdemonstrated a photocatalytic efficiency significantly higher than the reference TiO2 P25. Specifically,TiO2 NRs/Ag NPs showed a photoactivity in nalidixic acid degradation 14 times higher than TiO2 P25and 4 times higher than bare TiO2 NRs in the first 60 min of reaction. Several by-products were identifiedby HPLC-MS along the nalidixic acid degradation, thus getting useful insight on the degradation pathway.All the identified by-products resulted completely removed after 6 h of reaction

A great interest has been recently generated by the discovery that peptide-based nanostructures (NSs) endowed with cross-beta structure may show interesting photoluminescent (PL) properties. It was shown that NSs formed by PEGylated hexaphenylalanine (PEG(8)-F6, PEG=polyethylene glycol) are able to emit at 460 nm when excited at 370 or 410 nm. Here, the possibility to transfer the fluorescence of these PEG(8)-F6-based NSs by foster resonance electron transfer (FRET) phenomenon to a fluorescent dye was explored. To achieve this aim, the 4-chloro-7-nitrobenzofurazan (NBD) dye was encapsulated in these NSs. Structural data in solution and in solid state, obtained by a variety of techniques (circular dichroism, Fourier-transform infrared spectroscopy, wide-angle X-ray scattering, and small-angle X-ray scattering), indicated that the organization of the peptide spine of PEG(8)-F6 NS, which consists of anti-parallel beta-sheets separated by a dry interface made of interacting phenylalanine side chains, was maintained upon NBD encapsulation. The spectroscopic characterization of these NSs clearly showed a redshift of the emission fluorescence peak both in solution and in solid state. This shift from 460 to 530 nm indicated that a FRET phenomenon from the peptide-based to the fluorophore-encapsulated NS occurred. FRET could also be detected in the PEG(8)-F6 conjugate, in which the NBD was covalently bound to the amine of the compound. On the basis of these results, it is suggested that the red-shift of the intrinsic PL of NSs may be exploited in the bio-imaging field.

The plasma optical radiation emitted during CO2 laser welding of stainless steel samples has been detected with a Si-PIN photodiode and analyzed under different process conditions. The discrete wavelet transform (DWT) has been used to decompose the optical signal into various discrete series of sequences over different frequency bands. The results show that changes of the process settings may yield different signal features in the range of frequencies between 200 Hz and 30 kHz. Potential applications of this method to monitor in real time the laser welding processes are also discussed.

In the last few years, new drug delivery systems have been as one of the fewest responses for the treatment of the most aggressive diseases, including cancer. In this perspective, inorganic nanocrystals (NCs) offer the potential for a new and innovative approach for the targeted transport of drugs towards tissues affected by disease. A very important aspect is represented by the determination of the maximum cellular dose of these nanovectors, that is relevant for diagnostic and therapeutic applications both in-vitro and in-vivo tests [1]. Furthermore, the concentration of the nanovector is mandatory for the thorough characterization of the product required for any regulatory approval [2]. Accurate determination of the concentration is not a trivial issue and currently there is a lack of experimental methods recognized as general and reliable [3]. In this work, we propose an approach for the determination of the concentration of a solid lipid nanoparticle (SLN) nanovector encapsulating photoactive copper sulfide (Cu2-xS) NCs characterized by a tunable localized surface plasmon resonance (LSPR) in the near-infrared (NIR) spectral region, that is highly transparent for tissue, blood, and water [4]. Here, Cu2-xS NCs, synthesized by hot injection method, carefully tuning reaction conditions in order to achieve NCs with a narrow size distribution and an intense LSPR in the second biological window, have been encapsulated into SLN prepared by a hot homogenization technique using a mixture of cholesterol and triglycerides and phospholipids. A calculation method based on Mie-Drude theory using as input data resulting from spectroscopic characterization and transmission electron microscopy (TEM) and dynamic light scattering (DLS) investigation for the Cu2-xS NCs and NCs containing SLNs successfully provide the determination of the nanovector concentration (Figure 1). The results are in agreement with experimental data and such an approach represent a powerful tool for determining the concentration of plasmonic NCs based nanovectors regardless of their degree of complexity.

The in-process monitoring and real-time control of the penetration depth during laser welding is evaluated. An optical collimator collects the optical emission for measurement with a fast spectrometer. The sensor data are used to calculate the electron temperature and subsequently to determine the weld quality of overlap welds in AISI 304 stainless steel sheets performed both with CW Nd:YAG and CO2 lasers. A PI-controller adjusts the laser power aiming at a constant penetration depth and has been tested for Nd:YAG laser welding. Optical inspection of the weld verifies the results obtained with the proposed closed-loop system of spectroscopic sensor and controller.

An efficient microwave supported synthesis, with a reaction time of only one and a half minute, to prepare boron-modified titania nanocrystals TiO2:(B), was developed. The nanocrystals were obtained by hydrolysis of titanium tetraisopropoxide (TTIP) together with benzyl alcohol and boric acid, and the approach did not need surfactants use and a final calcination step. The produced TiO2:(B) nanocrystals were characterized in detail by low magnification Transmission Electron Microscopy (TEM), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), X-Ray Diffractometry (XRD), and a Micro Raman Spectroscopy. One of the obtained samples was then tested as an additive in various amounts in a typical aluminosilicate refractory composition. The effects of these additions in bricks were evaluated, according to UNI EN 196/2005, in terms of thermo-physical and mechanical properties: diffusivity, bulk density, apparent density, open and apparent porosity and cold crushing strength. Bricks' microstructure was analysed by Scanning Electron Microscopy (SEM) and energy dispersion spectroscopy (EDS). The bricks obtained with nanoadditives presented improved mechanical characteristics with respect to the typical aluminosilicates, presumably because of a better compaction during the raw materials' mixing stage.

Research on composite materials is facing, among others, the challenging task of incorporating nanocrystals, and their superstructures, in polymer matrices. Electron microscopy can typically image nanometre-scale structures embedded in thin polymer films, but not in films that are micron size thick. Here, X-ray Ptychography was used to visualize, with a resolution of a few tens of nanometers, how CdSe/CdS octapod-shaped nanocrystals self-assemble in polystyrene films of 24 ± 4 ?m, providing a unique means for non-destructive investigation of nanoparticles distribution and organization in thick polymer films.

The nanoscale structural order of air-dried rat-tail tendon is investigated using small-angle X-ray scattering (SAXS). SAXS fiber diffraction patterns were collected with a superbright laboratory microsource at XMI-LAB [Altamura, Lassandro, Vittoria, De Caro, Siliqi, Ladisa & Giannini (2012). J. Appl. Cryst. 45, 869-873] for increasing integration times (up to 10 h) and a novel algorithm was used to estimate and subtract background, and to deconvolve the beam-divergence effects. Once the algorithm is applied, the peak visibility improves considerably and reciprocal space information up to the 22nd diffraction order is retrieved (q = 0.21 angstrom(-1), d = 29 angstrom) for an 8-10 h integration time. The gain in the visibility is already significant for patterns collected for 0.5 h, at least on the more intense peaks. This demonstrates the viability of detecting structural changes on a molecular/nanoscale level in tissues with state-of-the-art laboratory sources and also the technical feasibility to adopt SAXS fiber diffraction as a future potential clinical indicator for disease.

We report on the instantaneous detection of the ablation rate as a function of depth during ultrafast microdrilling of metal targets. The displacement of the ablation front has been measured with a sub-wavelength resolution using an all-optical sensor based on the laser diode self-mixing interferometry. The time dependence of the laser ablation process within the depth of aluminum and stainless steel targets has been investigated to study the evolution of the material removal rate in high aspect-ratio micromachined holes.

High-energy ultra-short pulse laser ablation is a fast-growing technology in precision laser micromachining of transparent as well as opaque materials. Accurate in-situ measurements of physical parameters such as the penetration depth and the removal rate are crucial to fully characterize the ultrafast laser-material interactions [1-5]. Nonetheless, the laser drilling is still lacking of a real-time technique able to monitor and control the spatial- and time-dependent evolution of the hole-depth in metallic plates.

We study the incubation effect during laser ablation of stainless steel with ultrashort pulses to boost the material removal efficiency at high repetition rates. The multi-shot ablation threshold fluence has been estimated for two pulse durations, 650-fs and 10-ps, in a range of repetition rates from 50kHz to 1 MHz. Our results show that the threshold fluence decreases with the number of laser pulses N due to damage accumulation mechanisms, as expected. Moreover, approaching the MHz regime, the onset of heat accumulation enhances the incubation effect, which is in turn lower for shorter pulses at repetition rates below 600 kHz. A saturation of the threshold fluence value is shown to occur for a significantly high number of pulses, and well fitted by a modified incubation model. (C) 2014 Optical Society of America

Thanks to their high stability, good optoelectronic and extraordinary electrochromic properties, tungsten oxides are among the most valuable yet underexploited materials for energy conversion applications. Herein, colloidal one-dimensional carved nanocrystals of reduced tungsten trioxide (WO3-x) are successfully integrated, for the first time, as a hole-transporting layer (HTL) into CH3NH3PbI3 perovskite solar cells with a planar inverted device architecture. Importantly, the use of such preformed nanocrystals guarantees the facile solution-cast-only deposition of a homogeneous WO3-x thin film at room temperature, allowing achievement of the highest power conversion efficiency ever reported for perovskite solar cells incorporating raw and un-doped tungsten oxide based HTL.

Osteoarthritis (OA), among other bone pathologies, is expected to determine supramolecular changes at the level of the mineralized collagen fiber. In a proof-of-principle study, bone biopsies were collected from six coxarthritis-affected patients, aged 62-87 years, during hip prosthesis implant surgery, sliced down to 100 mm-thick tissues, and investigated using scanning small-angle and wide-angle X-ray scattering (SAXS and WAXS) transmission microscopy. A multimodal imaging evaluation of the SAXS and WAXS data, combined with principal component and canonical correlation analyses, allowed the transformation of the raw data into microscopy images and inspection of the nanoscale structure of the mineralized collagen fibers across mm 2 tissue areas. The combined scanning SAXS and WAXS microscopy is shown to be a suitable choice for characterizing and quantifying the nanostructural properties of collagen over extended areas. The results suggest the existence of a correlation between age and cross-linking-induced rigidity of collagen fibers.

Water soluble fibers of PEGylated tetra-phenylalanine (F4), chemically modified at the N-terminus with the DOTA chelating agent, have been proposed as innovative contrast agent (CA) in Magnetic Resonance Imaging (MRI) upon complexation of the gadolinium ion. An in-depth structural characterization of PEGylated F4-fibers, in presence (DOTA-L-6-F4) and in absence of DOTA (L-6-F4), is reported in solution and at the solid state, by a multiplicity of techniques including CD, FTIR, NMR, DLS, WAXS and SAXS. This study aims to better understand how the aggregation process influences the performance of nanostructures as MRI CAs. Critical aggregation concentrations for L-6-F4 (43 mu M) and DOTA-L-6-F4 (75 mu M) indicate that self-aggregation process occurs in the same concentration range, independently of the presence of the CA. The driving force for the aggregation is the pi-stacking between the side chains of the aromatic framework. CD, FTIR and WAXS measurements indicate an antiparallel beta-sheet organization of the monomers in the resulting fibers. Moreover, WAXS and FTIR experiments point out that in solution the nanomaterials retain the same morphology and monomer organizations of the solid state, although the addition of the DOTA chelating agent affects the size and the degree of order of the fibers.

All biomaterials initiate a tissue response when implanted in living tissues. Ultimately this reaction causes fibrous encapsulation and hence isolation of the material, leading to failure of the intended therapeutic effect of the implant. There has been extensive bioengineering research aimed at overcoming or delaying the onset of encapsulation. Nanotechnology has the potential to address this problem by virtue of the ability of some nanomaterials to modulate interactions with cells, thereby inducing specific biological responses to implanted foreign materials. To this effect in the present study, we have characterised the growth of fibroblasts on nano-structured sheets constituted by BaTiO3, a material extensively used in biomedical applications. We found that sheets of vertically aligned BaTiO3 nanotubes inhibit cell cycle progression - without impairing cell viability - of NIH-3T3 fibroblast cells. We postulate that the 3D organization of the material surface acts by increasing the availability of adhesion sites, promoting cell attachment and inhibition of cell proliferation. This finding could be of relevance for biomedical applications designed to prevent or minimize fibrous encasement by uncontrolled proliferation of fibroblastic cells with loss of material-tissue interface underpinning long-term function of implants.

In-process monitoring and feedback control are fundamental actions for stable and good quality laser welding process. In particular, penetration depth is one of the most critical features to be monitored. In this research, overlap welding of stainless steel is investigated to stably reproduce a fixed penetration depth using both CO 2 and Nd:YAG lasers. Plasma electron temperatures of Fe(I) and Cr(I) are evaluated as in process monitoring using the measurement of intensities of emission lines with fast spectrometers. The sensor system is calibrated using a quantitative relationship between electron temperature and penetration depth in different welding conditions. Finally closed loop control of the weld penetration depth is implemented by acquiring the electron temperature value and by adjusting the laser power to maintain a pre-set penetration depth. A PI controller is successfully used to stabilize the electron temperature around the set point corresponding to the right penetration depth starting from a wrong value of any initial laser power different than the set point. Optical inspection of the weld surface and macroscopic analyses of cross sections verify the results obtained with the proposed closed-loop system based on a spectroscopic controller and confirms the reliability of our system.

We have developed a general X-ray powder diffraction (XPD) methodology for the simultaneous structural and compositional characterization of inorganic nanomaterials. The approach is validated on colloidal tungsten oxide nanocrystals (WO3-x NCs), as a model polymorphic nanoscale material system. Rod-shaped WO3-x NCs with different crystal structure and stoichiometry are comparatively investigated under an inert atmosphere and after prolonged air exposure. An initial structural model for the as-synthesized NCs is preliminarily identified by means of Rietveld analysis against several reference crystal phases, followed by atomic pair distribution function (PDF) refinement of the best-matching candidates (static analysis). Subtle stoichiometry deviations from the corresponding bulk standards are revealed. NCs exposed to air at room temperature are monitored by XPD measurements at scheduled time intervals. The static PDF analysis is complemented with an investigation into the evolution of the WO3-x NC structure, performed by applying the modulation enhanced diffraction technique to the whole time series of XPD profiles (dynamical analysis). Prolonged contact with ambient air is found to cause an appreciable increase in the static disorder of the O atoms in the WO3-x NC lattice, rather than a variation in stoichiometry. The time behavior of such structural change is identified on the basis of multivariate analysis.

Peptides containing aromatic residues are known to give spontaneous phenomena of supramolecular organization into ordered nanostructures (NSs). Here we studied the structural behavior and the optoelectronic properties of new biocompatible materials obtained by self-assembling of a series of hexaphenylalanines (F6) modified at the N-terminus with a PEG chain of different length. PEG12-F6, PEG18-F6 and PEG24-F6 peptides were synthesized by coupling sequentially two, three or four units of amino-carboxy PEG6 blocks, each one containing six ethoxylic repetitions. Changes in length and composition of the PEG chain were found able to modulate the structural organization of phenylalanine based nanostructures. An increase in the self-aggregation tendency with longer PEG is observed; while, independently from PEG length, the peptide NSs display cross-beta like secondary structure with an antiparallel beta-strand arrangement. WAXS/GIWAXS diffraction patterns indicate a progressive decrease of the fiber order along the series. All the PEG-F6 derivatives present blue photoluminescent (PL) emission at 460 nm, while the adduct with longest PEG (PEG24-F6) shows an additional green emission at 530 nm.

Over the years, a large number of multidisciplinary investigations has unveiled that the self-assembly of short peptides and even of individual amino acids can generate a variety of different biomaterials. In this framework, we have recently reported that polyethylene glycol (PEG) conjugates of short homopeptides, containing aromatic amino acids such as phenylalanine (Phe, F) and naphthylalanine (Nal), are able to form elongated fibrillary aggregates having interesting chemical and physical properties. We here extend these analyses characterizing the self-assembling propensity of PEG(6)-W4, a PEG adduct of the tetra-tryptophan (W4) sequence. A comprehensive structural characterization of PEG(6)-W4 was obtained, both in solution and at the solid state, through the combination of spectroscopic, microscopic, X-ray scattering and computational techniques. Collectively, these studies demonstrate that this peptide is able to self-assemble in fibrillary networks characterized by a cross -structure spine. The present findings clearly demonstrate that aromatic residues display a general propensity to induce self-aggregation phenomenon, despite the significant differences in the physicochemical properties of their side chains.

Ribosome biogenesis is closely linked to the cell growth and proliferation. Dysregulation of this process causes several diseases collectively known as ribosomopathies. One of them is the Shwachman-Diamond Syndrome, and the SBDS protein mutated in this disease participates with EFL1 in the cytoplasmic maturation of the 60S subunit. Recently, we have shown that the interaction of EFL1 with SBDS resulted in a decrease of the Michaelis-Menten constant (KM) for GTP and thus SBDS acts as a GEF for EFL1 (1). Subsequent studies demonstrated that SBDS greatly debilitates the interaction of EFL1 with GDP without altering that for GTP. The interaction of EFL1 alone or in complex with SBDS to guanine nucleotides is followed by a conformational rearrangement. Understanding the molecular strategy used by SBDS to disrupt the binding of EFL1 for GDP and the associated conformational changes will be key to understand their mode of action and alterations occurring in the disease. The structure of the GTPase EFL1 is not known and its crystallization has been unsuccessful at least in our hands. In this study, we aim to show the conformational changes resulting from the interactions between EFL1 and its binding partners, the SBDS protein and the guanine nucleotides using SAXS technique (2, 3). SAXS will provide structural information of the proteins and their conformational changes (4). For the SAXS data analysis we have built models of EFL1 using by EF-2 as homology template and of SBDS using the crystal structures of the archaea orthologues.

The plasma electron temperature has been estimated starting from the spectroscopic analysis of the optical emission of the laser-generated plasma plume during quite diverse stainless steel welding procedures (c.w. CO 2 and pulsed Nd:YAG). Although the optical emissions present different spectral features, a discrete contribution of several iron lines can be highlighted in both types of welding. We have found that the electron temperature decreases as the laser power is enhanced, in static as well as dynamic conditions. Such a result could be useful to develop a closed loop control system of the weld penetration depth.

SUNBIM (Supramolecular & SUbmolecular Nano & Bio Materials X-ray IMaging Project) is a suite of integrated programs developed, in collaboration with Rigaku Innovative Technologies, to treat Small and Wide Angle X-ray Scattering data, collected either in transmission geometry (SAXS/WAXS) or in reflection geometry (GISAXS/GIWAXS). In addition, a specific routine to collect and analyze data in SAXS scanning transmission microscopy has been developed as additional tool to investigate tissues or material science samples through a focused X-ray beam which is used to raster scan a specimen while acquiring SAXS scattering patterns with a 2D detector. Indeed, a first-generation-synchrotron-class FrE+ SuperBright Rigaku microsource, coupled to a three pinhole S-MAX3000 camera, was recently installed at the X-ray MicroImaging Laboratory (XMI-L@b) and used with success in SAXS/WAXS/GISAXS/GIWAXS experiments (De Caro et al, 2012; 2013)and for SAXS scanning microscopy (Altamura et al, 2012; Giannini et al, 2013).

SUNBIM (supramolecular and submolecular nano- and biomaterials X-rayimaging) is a suite of integrated programs which, through a user-friendlygraphical user interface, are optimized to perform the following: (i) q-scalecalibration and two-dimensional ! one-dimensional folding on small- andwide-angle X-ray scattering (SAXS/WAXS) and grazing-incidence SAXS/WAXS (GISAXS/GIWAXS) data, also including possible eccentricity correctionsfor WAXS/GIWAXS data; (ii) background evaluation and subtraction,denoising, and deconvolution of the primary beam angular divergence onSAXS/GISAXS profiles; (iii) indexing of two-dimensional GISAXS frames andextraction of one-dimensional GISAXS profiles along specific cuts; (iv) scanningmicroscopy in absorption and SAXS contrast. The latter includes collection oftransmission and SAXS data, respectively, in a mesh across a mm2 area,organization of the as-collected data into a single composite image oftransmission values or two-dimensional SAXS frames, analysis of the composeddata to derive the absorption map and/or the spatial distribution, andorientation of nanoscale structures over the scanned area.

Drops of exosome dispersions from healthy epithelial colon cell line and colorectal cancer cells were dried on a superhydrophobic PMMA substrate. The residues were studied by small- and wide-angle X-ray scattering using both a synchrotron radiation micrometric beam and a high-flux table-top X-ray source. Structural differences between healthy and cancerous cells were detected in the lamellar lattices of the exosome macro-aggregates.

Ultrafast laser ablation in liquids is an easy, fast and versatile method to generate nanoparticles. Metal nanoparticles have been demonstrated to possess excellent antimicrobial properties thanks to their very high surface area to volume ratios which provide better contact with microorganisms [1]. For this reason, they are attracting growing interest as a base to develop novel nanocomposites preventing biocontamination in several application fields. In particular, copper nanoparticles (CuNPs) can be used, under controlled ionic release conditions [2], to inhibit bacteria proliferation in food packaging [3] as well as in other applications in medicine, agriculture or pharmaceuticals. In order to prevent human toxicity, CuNPs need to be carefully embedded into polymer matrices acting as immobilizing component and potentially bringing additional properties to the final nanocomposite [4]. Among the possible dispersing polymers, chitosan (CS) is a well-known antimicrobial material, widely exploited for its biodegradability and nontoxicity [5]. © 2013 IEEE.

Phase separation of a polymer solution exhibits a peculiar behavior when induced in a nanoconfinement. The energetic constraints introduce additional interactions between the polymer segments that reduce the number of available configurations. In our work, this effect is exploited in a one-step strategy called nanoconfined-Thermally Induced Phase Separation (nc-TIPS) to promote the crystallization of polymer chains into nanocapsular structures of controlled size and shell thickness. This is accomplished by performing a quench step of a low-concentrated PLLA-dioxane-water solution included in emulsions of mean droplet size < 500 nm acting as nanodomains. The control of nanoconfinement conditions enables not only the production of nanocapsules with a minimum mean particle diameter of 70 nm but also the tunability of shell thickness and its crystallinity degree. The specific properties of the developed nanocapsular architectures have important implications on release mechanism and loading capability of hydrophilic and lipophilic payload compounds.

The present investigation reported the synthesis of ultrafine anatase titanium dioxide (TiO2) nanocrystals using titanium isopropoxide (TTIP) as precursor in presence of benzyl alcohol as solvent and glucose as capping agent via a microwave-solvothermal method. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption, micro Raman and Fourier transform infrared spectroscopies (FT-IR). From this preparation method it was demonstrated that the obtainable TiO2 nanocrystals were less than 10 nm in mean size, mainly in anatase phase, presenting also a mesoporous structure. The use of glucose as capping agent added in the reaction system played a role in the anisotropic growth of the TiO2 nanocrystals, as evidenced by XRD domain size analysis and promoted an increase of the specific surface area.

Colloidal semiconductor nanocrystals, with intense and sharp-line emission between red andnear-infrared spectral regions, are of great interest for optoelectronic and bio-imagingapplications. The growth of an inorganic passivation layer on nanocrystal surfaces is a commonstrategy to improve their chemical and optical stability and their photoluminescence quantumyield. In particular, cation exchange is a suitable approach for shell growth at the expense of thenanocrystal core size. Here, the cation exchange process is used to promote the formation of aCdS passivation layer on the surface of very small PbS nanocrystals (2.3 nm in diameter), blueshifting their optical spectra and yielding luminescent and stable nanostructures emitting in therange of 700-850 nm. Structural, morphological and compositional investigation confirms thenanocrystal size contraction after the cation-exchange process, while the PbS rock-salt crystallinephase is retained. Absorption and photoluminescence spectroscopy demonstrate the growth of apassivation layer with a decrease of the PbS core size, as inferred by the blue-shift of theexcitonic peaks. The surface passivation strongly increases the photoluminescence intensity andthe excited state lifetime. In addition, the nanocrystals reveal increased stability against oxidationover time. Thanks to their absorption and emission spectral range and the slow recombinationdynamics, such highly luminescent nano-objects can find interesting applications in sensitizedphotovoltaic cells and light-emitting devices.

The peculiar architecture of a novel class of anisotropic TiO2(B) nanocrystals, which were synthesized by an surfactant-assisted nonaqueous sol-gel route, was profitably exploited to fabricate highly efficient mesoporous electrodes for Li storage. These electrodes are composed of a continuous spongy network of interconnected nanoscale units with a rod-shaped profile that terminates into one or two bulgelike or branch-shaped apexes spanning areas of about 5 x 10 nm(2). This architecture transcribes into a superior cycling performance (a charge capacitance of 222 mAh g(-1) was achieved by a carbon-free TiO2(B)-nanorods-based electrode vs 110 mAh g(-1) exhibited by a comparable TiO2-anatase electrode) and good chemical stability (more than 90% of the initial capacity remains after 100 charging/discharging cycles). Their outstanding lithiation/delithiation capabilities were also exploited to fabricate electrochromic devices that revealed an excellent coloration efficiency (130 cm(2) C-1 at 800 nm) upon the application of 1.5 V as well as an extremely fast electrochromic switching (coloration time similar to 5 s).

During recent decades innovative nanomaterials have been extensively studied, aiming at both investigating the structure-property relationship and discovering new properties, in order to achieve relevant improvements in current state-of-the art materials. Lately, controlled growth and/or assembly of nanostructures into hierarchical and complex architectures have played a key role in engineering novel functionalized materials. Since the structural characterization of such materials is a fundamental step, here we discuss X-ray scattering/diffraction techniques to analyze inorganic nanomaterials under different conditions: dispersed in solutions, dried in powders, embedded in matrix, and deposited onto surfaces or underneath them.