Topological two-body bound states in the interacting Haldane model

We study the topological properties of the two-body bound states in an interacting Haldane model as a function of interparticle interactions. In particular, we identify topological phases where the two-body edge states have either the same or the opposite chirality as compared to single-particle edge states. We highlight that in the moderately interacting regime, which is relevant for the experimental realization with ultracold atoms, the topological transition is affected by the internal structure of the bound state, and the phase boundaries are consequently deformed

Dentistry on the bridge to Nanoscience and Nanotechnology

Dentistry is the area of medical sciences that is most resistant to the introduction of the novel methods arisen from the development of nanoscience and nanotechnology in the last 20 years. Without moving on to science fiction like views pointing to times far ahead in the future, we show that the available nanoscale devices and processes of current science and technology, partly inherited from the areas of microscopy and microelectronics, have already proven to be useful for research and development in different fields of dental research. To this goal, we review some results obtained in the last few years at our Institute in the area of dental materials and their characterization, which showed successful application of our background in microscopy and nanoengineering

Twisted graphene in graphite: Impact on surface potential and chemical stability

Abstract Highly-oriented pyrolytic graphite (HOPG), i.e., the 3D stack of sp2-hybridized carbon sheets, is an attractive material thanks to its high electrical conductivity, chemical inertness, thermal stability, atomic-scale flatness, and ease of exfoliation. Despite an apparently ideal and uniform material, freshly cleaved HOPG shows domains in Kelvin probe force microscopy (KPFM) with surface potential contrast over 30 mV. We systematically investigated these domains using an integrated approach, including time-dependent KPFM and hyperspectral Raman imaging. The observed time-evolving domains are attributed to locally different hydrocarbon adsorption from the environment, driven by structural defects likely related to rotational mismatch, i.e., twisted layers. These defects affect the interlayer coupling between topmost graphene and the underlying layers. Our hypothesis was supported by Raman spectroscopy results, showing domains with G peak shifts and 2D line shape compatible with bilayer graphene. We attribute the selective sensitivity of our Raman spectroscopy results to the top graphene layers as resonances due to van Hove singularities. Our results show that the chemical and electrical properties of HOPG are far more complex than what is generally believed due to the broken symmetry at the top surface, giving rise to graphene bilayer-like behavior

Advances in Electrospun Nanofibers

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Increased growth rate of anodic porous alumina by use of ionic liquid as electrolyte additive

The use of ionic liquids 1-Butyl-3-methylimidazolium 2-(2-methoxyethoxy) ethyl sulfate and 1-Butyl-3-methylimidazolium tetrafluoborate has been tested in the fabrication of anodic porous alumina. The anodizations of the aluminium substrate have been carried out in oxalic acid in galvanostatic mode. During anodization with 1-Butyl-3-methylimidazolium tetrafluoborate added electrolyte, proper tuning of the current density and of the additive concentration resulted in a three-fold increase of the growth rate as compared to the bare acidic solution with the same acid concentration. This did not cause cracks in the film during growth, and did not affect the regular structure of the pores at the interface with the substrate

Serum Cystatin C for the diagnosis of acute Kidney Injury in Patients Admitted in the Emergency Department

BACKGROUND: Early diagnosis of acute kidney injury (AKI) at emergency department (ED) is a challenging issue. Current diagnostic criteria for AKI poorly recognize early renal dysfunction and may cause delayed diagnosis. We evaluated the use of serum cystatin C (CysC) for the early and accurate diagnosis of AKI in patients hospitalized from the ED. METHODS: In a total of 198 patients (105 males and 93 females), serum CysC, serum creatinine (sCr), and estimated glomerular filtration rate (eGFR) were calculated at 0, 6, 12, 24, 48, and 72 hours after presentation to the ED. We compared two groups according to the presence or absence of AKI. RESULTS: Serial assessment of CysC, sCr, and eGFR was not a strong, reliable tool to distinguish AKI from non-AKI. CysC > 1.44 mg/L at admission, both alone (Odds Ratio = 5.04; 95%CI 2.20-11.52; P < 0.0002) and in combination with sCr and eGFR (Odds Ratio = 5.71; 95%CI 1.86-17.55; P < 0.002), was a strong predictor for the risk of AKI. CONCLUSIONS: Serial assessment of CysC is not superior to sCr and eGFR in distinguishing AKI from non-AKI. Admission CysC, both alone and in combination with sCr and eGFR, could be considered a powerful tool for the prediction of AKI in ED patients

Near-field spectroscopy of phase segregation in white-light-emitting blends based on low-mass molecules

We report on the direct observation of phase segregation occurring in thin-film blends of a thiophene monomer and an ammino compound, used in the fabrication of organic white-light-emitting diodes. In the homogeneous and uniform regions of the films, the interaction between the two molecular components gives rise to exciplex states responsible for a broad redshifted photoluminescence emission band, which disappears in the film zones where segregation occurs. This effect has been observed with submicrometer spatial resolution by means of local spectroscopic measurements performed in a scanning near-field optical microscope

Adhesion of sea-urchin living cells on nano-patterned anodic porous alumina

In this work we investigated the possibility of using living cells as stress sensing material in biosensors, in the light of the three Rs principle \u2013 Replacement, Reduction and Refinement . This approach requires the necessity to cultivate them on biocompatible electrical conducting substrate and to insert the circuit into a culture chamber that must assure both the transport of oxygen and the diffusion of the medium containing the potential stressor to the cells, without modifying their response and the structure of the culture. To this aim we fabricated nano-patterned substrates of anodic porous alumina to be used for enhancing cell adhesion, and culture chambers made in polylactic acid. Sea-urchin cells (coelomocytes) were cultured on these substrates at different times of 1, 3 and 5 days in vitro. Since these cells are progenitors of immune cells in vertebrate systems (blood cells), they carry out similar functions. For this reason, although they can differ considerably from vertebrates, they have been proved to be very promising sentinels of environmental water qualit

Cobalt-based nanoparticles synthesis in organic solvents with environmentally sound processes

A process for the synthesis of cobalt-based nanoparticles is proposed, where standard reducing agent like hydrazine, alkali metal borohydrides, hypophosphites or other toxic reducing agents have not been employed. The solvothermal reaction is carried out in organic solvents and the dimension of the nanoparticles thus obtained have been analyzed by dynamic light scattering. Cobalt nitrate proved to be an efficient precursor, in agreement with previous literature works where its suitability for analogous processes has been tested and compared with the efficiency typical of other precursors routinely used. The soundness of this method, in terms of process safety, has been checked by analyzing the formation of toxic by-products that could be formed by side-reactions between the precursor and the solvent. This work may add some more details to a discussion pertaining to the accidental formation of N-nitroso derivatives of aliphatic compounds in the presence of alkanolamines and oxides of nitrogen

Low-pressure plasma treatment of CFRP substrates for epoxy-adhesive bonding: an investigation of the effect of various process gases

This work reports a systematic and quantitative evaluation of the effects induced on the adhesive properties of carbon fiber reinforced polymer (CFRP) substrates by various vacuum cold-plasma treatments. In particular, surface activation of the CFRP substrates was performed using several combinations of exposure time, plasma power, and processing gas (air, O 2 , Ar and N 2 ). By comparing these plasma treatments with conventional techniques of abrasion and peel ply, it was possible to substantially increase the performance of the adhesively bonded joints made by overlapping the CFRP substrates with a structural epoxy resin. On each differently treated surface, measurements of roughness and of wettability were performed, allowing the evaluation of the increase in surface energy after the plasma treatment. XPS analyses allowed the identification of the chemical state of the substrates and showed an in-depth functionalization of the outer layer of the CFRP material. The experimental results show that an engineered plasma treatment of the CFRP substrates allows one to modify the surface morphology and both wetting and chemical activation properties of the treated surfaces, resulting in an increased mechanical shear strength of the joints