Wetting Modification by Photocatalysis: A Hands-on Activity To Demonstrate Photoactivated Reactions at Semiconductor Surfaces

We present a hands-on activity designed for advanced physical chemistry courses for Master\u2019s students on the application of photocatalysis to the modification of the surface properties of a semiconductor (titanium dioxide). The wetting properties of TiO2 films, deposited from commercial powders, are studied before and after UV irradiation. Irradiation-induced superhydrophilicity is exploited to provide antifogging properties. The TiO2 films are then functionalized with a perfluorinated alkylsilane to impart superhydrophobicity and subsequently lithographed by irradiation through a photomask: the photocatalytic degradation of the organic chains in the irradiated areas leads to a wetting contrast that can be revealed using dye solutions. This experience can be easily adapted to be suited for undergraduates or high-school students as well as to demonstrations for science festivals

Implementation of the Hierarchical Reference Theory for simple one-component fluids

Combining renormalization group theoretical ideas with the integral equation approach to fluid structure and thermodynamics, the Hierarchical Reference Theory is known to be successful even in the vicinity of the critical point and for sub-critical temperatures. We here present a software package independent of earlier programs for the application of this theory to simple fluids composed of particles interacting via spherically symmetrical pair potentials, restricting ourselves to hard sphere reference systems. Using the hard-core Yukawa potential with z=1.8/sigma for illustration, we discuss our implementation and the results it yields, paying special attention to the core condition and emphasizing the decoupling assumption's role.Comment: RevTeX, 16 pages, 2 figures. Minor changes, published versio

Mesoporous silica networks with improved diffusion and interference-rejecting properties for electroanalytical sensing

Mesoporous silica materials characterized by well-ordered microstructure and size- and shape-controlled pores have attracted much attention in the last years. These systems can be used for the development of functional thin films for advanced applications in catalysis and electrocatalysis, sensors and actuators, separation techniques, micro- and nano-electronic engineering [1-2]. In this work, \u201cinsulating\u201d and mesoporous silica films were prepared by spin coating a home-made silica sol on a cleaned ITO glass support. The mesoporosity was controlled by the use of Polystyrene (PS) latex beads with different dimensions (30-60-100 nm) as template. The number of successive multi-layer depositions was varied (1-2-3-5 layers) and after the template removal, stable, homogeneous and reproducible transparent films were obtained, characterized by an interconnected porous structure. The morphological features and the physicochemical and optical properties of the films and/or sol-precursors were studied by DLS, FE-SEM, AFM, UV-vis transmittance spectroscopy and wettability analyses. Moreover, a deep electrochemical characterization was also performed by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). In particular, the use of two redox mediator probes [(K4Fe(CN)6) and (Ru(NH3)6Cl3)], presenting opposite charge and different diffusional behaviour, allowed the comprehension of the mass transport and charge transfer phenomena, evidencing the effects of spatial confinement and charge selection. In the case of \u201cinsulating\u201d films prepared without the use of PS latexes, we proved an experimental evidence for theoretical models [3] concerning electroinactive layer-modified electrodes, with a scan-rate-dependent variation of the CV shape due to a progressive increase in the diffusion coefficient inside the insulating layer. A complex balance between diverging effects (higher hydrophilicity and insulating behavior effects of silica) when increasing the numbers of layers was also observed [4]. In the case of mesoporous layers, a better electrochemical response of smaller pores and of thicker layers was found, due to two main cooperative phenomena: i) a diffusion modification from fully planar to radial-convergent at the pore-silica interface due to surface porosity; ii) the presence of pores in a hydrophilic matrix which leads to a capillary pull effects, stronger in the case of smaller hydrophilic pores. The easiness of preparation and the interesting properties of these devices pave the way towards their use in many fields, particularly trace electroanalysis in real matrices. In fact, for example, the porous and properly charged network is able to exclude interfering macromolecules (mucin in our case), preventing electrode biofouling and enhancing the performances of the sensor towards dopamine detection. References [1] M. Ogawa, Chem. Rec. 17 (2017) 217-232. [2] A. Walcarius, Chem. Soc. Rev. 42 (2013) 4098-4140. [3] D. Menshykau, R.G. Compton, Langmuir 25 (2009) 2519\u20132529. [4] V. Pifferi, L. Rimoldi, D. Meroni, F. Segrado, G. Soliveri, S. Ardizzone, L. Falciola, Electrochem. Commun. 81 (2017) 102-105

Infinite compressibility states in the Hierarchical Reference Theory of fluids. II. Numerical evidence

Continuing our investigation into the Hierarchical Reference Theory of fluids for thermodynamic states of infinite isothermal compressibility kappa[T] we now turn to the available numerical evidence to elucidate the character of the partial differential equation: Of the three scenarios identified previously, only the assumption of the equations turning stiff when building up the divergence of kappa[T] allows for a satisfactory interpretation of the data. In addition to the asymptotic regime where the arguments of part I (cond-mat/0308467) directly apply, a similar mechanism is identified that gives rise to transient stiffness at intermediate cutoff for low enough temperature. Heuristic arguments point to a connection between the form of the Fourier transform of the perturbational part of the interaction potential and the cutoff where finite difference approximations of the differential equation cease to be applicable, and they highlight the rather special standing of the hard-core Yukawa potential as regards the severity of the computational difficulties.Comment: J. Stat. Phys., in press. Minor changes to match published versio

Integrated smart system for energy audit: methodology and application

Abstract The article describes the design and the application stage of a smart energy audit system, integrated within building, and the methodologies adopted for the detection of malfunctions of the plant. The system is set up as a "black box" consisting of a hardware aimed at logging both energy and environmental parameters and a software for the assessment of building behavior and the management of energy flows. The Energy Signature was chosen as the reference method for the evaluation of the energy performance of building. The system was tested in an existing public office building

High sensitivity double beta decay study of 116-Cd and 100-Mo with the BOREXINO Counting Test Facility (CAMEO project)

The unique features (super-low background and large sensitive volume) of the CTF and BOREXINO set ups are used in the CAMEO project for a high sensitivity study of 100-Mo and 116-Cd neutrinoless double beta decay. Pilot measurements with 116-Cd and Monte Carlo simulations show that the sensitivity of the CAMEO experiment (in terms of the half-life limit for neutrinoless double beta decay) is (3-5) 10^24 yr with a 1 kg source of 100-Mo (116-Cd, 82-Se, and 150-Nd) and about 10^26 yr with 65 kg of enriched 116-CdWO_4 crystals placed in the liquid scintillator of the CTF. The last value corresponds to a limit on the neutrino mass of less than 0.06 eV. Similarly with 1000 kg of 116-CdWO_4 crystals located in the BOREXINO apparatus the neutrino mass limit can be pushed down to m_nu<0.02 eV.Comment: 29 pages, LaTex, 9 eps figure

Anti-fibroblast antibodies detected by cell-based ELISA in systemic sclerosis enhance the collagenolytic activity and matrix metalloproteinase-1 production in dermal fibroblasts

Objectives. Antibodies binding to the surface of fibroblasts (anti-fibroblast antibodies: AFA) have been described in systemic sclerosis (SSc). We aimed to assess the effect of AFA on extracellular matrix (ECM) turnover and whether AFA were associated with anti-topoisomerase-I antibody. Methods. IgG were purified from AFA-positive and AFA-negative sera selected within 20 SSc and 20 healthy individuals, and tested on normal dermal fibroblasts, at protein and mRNA level, for their capacity to induce collagen deposition or degradation. Results. Fibroblasts stimulated with AFA-positive but not with AFA-negative and control IgG showed an increased capacity to digest collagen matrix and produce metalloproteinase-1 (MMP-1) while their production of total collagen, type I collagen and tissue inhibitor of metalloproteinase-1 (TIMP-1) was unaffected. The steady-state mRNA levels of MMP-1, COL1A1 and TIMP-1 paralleled the protein levels. AFA-positive IgG did not induce Smad 2/3 phosphorylation, indicating that this transforming growth factor-β signalling pathway was not involved. IL-1 and tumour necrosis factor (TNF) neutralization did not reverse the enhanced production of MMP-1, suggesting a direct effect of AFA on fibroblasts. Finally, anti-topoisomerase-I antibodies were present in 11 of 12 AFA-negative IgG, and an anti-topoisomerase-I monoclonal antibody failed to enhance MMP-1 production, thus indicating a lack of correlation between AFA and anti-topoisomerase-I antibody. Conclusions. These results indicate that SSc antibodies binding to fibroblasts enhance matrix degradation and MMP production events that may favour inflammation but do not directly impact on fibrosis developmen

Mir-101-3p downregulation promotes fibrogenesis by facilitating hepatic stellate cell transdifferentiation during insulin resistance

Insulin resistance (IR) and microRNAs (miRNAs), which regulate cell-to-cell communication between hepatocytes and hepatic stellate cells (HSCs), may intertwine in nonalcoholic fatty liver disease (NAFLD) pathogenesis. The aim of this study was to evaluate whether epigenetics and environmental factors interact to promote progressive NAFLD during IR. We examined the miRNA signature in insulin receptor haploinsufficient (InsR+/ 12) and wild-type (wt) HSCs by RNAseq (n = 4 per group). Then, we evaluated their impact in an IR-NASH (nonalcoholic steatohepatitis) model (InsR+/ 12 mice fed standard or methionine choline deficient (MCD) diet, n = 10 per group) and in vitro. InsR+/ 12 HSCs displayed 36 differentially expressed miRNAs (p &lt; 0.05 vs. wt), whose expression was then analyzed in the liver of InsR+/ 12 mice fed an MCD diet. We found that miR-101-3p negatively associated with both InsR+/ 12 genotype and MCD (p &lt; 0.05) and the histological spectrum of liver damage (p &lt; 0.01). miR-101-3p was reduced in InsR+/ 12 hepatocytes and HSCs and even more in InsR+/ 12 cells exposed to insulin (0.33 \ub5M) and fatty acids (0.25 mM), resembling the IR-NASH model. Conversely, insulin induced miR-101-3p expression in wt cells but not in InsR+/ 12 ones (p &lt; 0.05). In conclusion, IR combined with diet-induced liver injury favors miR-101-3p downregulation, which may promote progressive NAFLD through HSC and hepatocyte transdifferentiation and proliferation

Grammatical and contextual factors affecting the interpretation of superordinate collectives in child and adult Mandarin

The semantics of superordinate collectives (superordinates hereafter) such as English furniture are argued to be count or mass, or to allow both count and mass readings. When tested experimentally, however, it has repeatedly been reported that superordinates denote individuals in a wide range of typologically distinct languages, including Mandarin. A close examination of the experimental method and design commonly used in previous research suggests, however, that the attested individual-denoting reading might only be the preferred reading in neutral contexts rather than the only reading that superordinates allow. In the present study, using a Truth Value Judgment Task we investigate the interpretation of Mandarin superordinates by Mandarin-speaking adults and 4–6-year-old children. We found that bare superordinates can convey both individual-denoting and non-individual-denoting readings depending on specific contexts provided, but such contextual manipulation cannot override morphosyntax (the presence of an individual classifier that selects an individual-denoting reading only). Taken together, our experimental data indicate that both contextual and morphosyntactic information play an important role in the interpretation of Mandarin superordinates, but that they function in different ways. In a word, the present study contributes new data and opens new perspectives for further investigation in the interpretation of superordinates in Mandarin as well as in other languages