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

Behaviour of a Geogrid Reinforced Embankment over Waste Material

The paper deals with the monitoring of a geogrid reinforced embankment, 5.0 m high and 600 m long, built to contain additional waste material in the municipal landfill in Modena (Northern Italy). The embankment was founded directly over the waste already placed in the landfill, consisting of\u27 compressible and dishomogeneus material, varying from solid urban waste to muddy industrial material. The geotechnical parameters assumed to characterize the fill soil and the waste material of the foundation soil are described. The settlements of the embankment and the forces and strains in the geogrids were monitored from the beginning of the construction until some months later. The instrumentation used in order to perform this control is described. The actual results are compared with those obtained from the design model and with other field tests concerning geogrid reinforced structures

Microstructure evolution and mechanical properties of hot deformed Mg9Al1Zn samples containing a friction stir processed zone

During the last decade, FSP of magnesium alloys has become more popular due to the potential microstructure refinement of their eutectic phases, and interest has increased around the AZ1 that is one of the most commercially used magnesium alloys. In this work, high pressure die cast AZ91 plates were tensile tested at high temperatures after friction stir processing (FSP), with the stirred region in the middle of the gauge length. Samples deformed at 350 °C revealed an increment of ductility that was doubled as compared to those deformed at 300 °C and a strengthening of the nugget was measured by Vickers microhardness (HV). The correlation of HV average values to local grain size confirmed the validity of the Hall–Petch type equation where stress is replaced by hardness. X-rays diffraction and electrical conductivity highlighted the potential increment of solute atoms in solid solution during FSP. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) investigations performed on as-FSPed and hot deformed samples determined MgAlZn and AlMn particles type evolution through statistical analysis that supported mechanical properties and the strengthening mechanisms. Keywords: AZ91, Friction stir processing, Mechanical properties, Microstructure, SEM, TE

Nanosensors for cancer detection.

Cancer is a major burden in today's society and one of the leading causes of death in industrialised countries. Various avenues for the detection of cancer exist, most of which rely on standard methods, such as histology, ELISA, and PCR. Here we put the focus on nanomechanical biosensors derived from atomic force microscopy cantilevers. The versatility of this novel technology has been demonstrated in different applications and in some ways surpasses current technologies, such as microarray, quartz crystal microbalance and surface plasmon resonance. The technology enables label free biomarker detection without the necessity of target amplification in a total cellular background, such as BRAF mutation analysis in malignant melanoma. A unique application of the cantilever array format is the analysis of conformational dynamics of membrane proteins associated to surface stress changes. Another development is characterisation of exhaled breath which allows assessment of a patient's condition in a non-invasive manner

Some triviality results for quasi-Einstein manifolds and Einstein warped products

In this paper we prove a number of triviality results for Einstein warped products and quasi-Einstein manifolds using different techniques and under assumptions of various nature. In particular we obtain and exploit gradient estimates for solutions of weighted Poisson-type equations and adaptations to the weighted setting of some Liouville-type theorems.Comment: 15 pages, fixed minor mistakes in Section

Efficient methodology to produce a duloxetine precursor using whole cells of Rhodotorula rubra

Different types of yeasts were employed as biocatalysts in the reduction of \u3b2-ketonitriles. The red microorganism, Rhodotorula rubra, was selected as the best performing catalyst in the reduction of different substituted ketonitriles giving total stereoselectivity in most cases (90-99% ee). In particular, its use as fresh and lyophilised cells was expanded to a semi-preparative scale for the production of the duloxetine precursor 1a. R. rubra was screened in the reduction of alkylation products in comparison with Pichia henricii for assignment of configuration of products 2a and 11a after derivatisation with S-MPA

Operative Treatment and Clinical Outcomes in Peripheral Vascular Trauma: The Combined Experience of Two Centers in the Endovascular Era

Background: Arterial traumas of the extremities are quite rare in civilian records; nevertheless, patients with trauma of limbs are admitted daily in emergency departments worldwide. The upto-date information about epidemiology and treatment (open vs. endovascular surgery) comes from war records and it is not always easy getting data on mortality and morbidity in these patients. The aim of this study is to analyze the approach (open or endovascular) and the outcome of patients with vascular trauma of upper limbs (from the subclavian artery) and/or lower limbs (distal to the inguinal ligament), in the greater Milan area. Methods: A retrospective analysis was conducted on data recorded by the emergency departments of two hospitals of the greater Milan between 2009 and 2017. We collected all patients with arterial injuries of the limbs in terms of demography, injury patterns, clinical status at admission, therapy (open or endovascular approach), and outcomes in terms of limb salvage and survival. Results: We studied 52 patients with vascular trauma of extremities. The main mechanism of trauma was road accident (48.1%), followed by criminal acts (32.7%), self-endangering behavior (13.5%), work (3.8%), and sport accidents (1.9%). Associated lesions (orthopedic, neurological, and/or venous lesions of the limbs) were present in 39 patients (75%). All patients underwent emergency surgery, forty-six patients (88.5%) by open repair (polytetrafluoroethylene or greater saphenous vein bypass grafts, arterial suture or ligation), whereas endovascular approach was used only in 6 patients (11.5%), all treated with embolization. The overall postoperative mortality rate was 5.7% (3 patients). Among survivors, we report 5 major amputations of the lower limbs, 3 of them after bypass graft infection, and 2 after graft failure. The rate of limb salvage was 90.4%. Conclusions: Isolated arterial trauma of the extremities are rare, usually they occur in the setting of multiple trauma patients. Despite progresses in surgical techniques, there are still controversies in diagnosis and treatment of these patients. We treated most cases with open surgery (n = 46), choosing endovascular approach (embolization performed mainly by interventional radiologists) in difficult anatomic districts. We believe that, during decision-making of the surgical strategy, it is important to consider the anatomical site of lesions and the general condition of the patients. Moreover, in case of multiple trauma, we suggest a multidisciplinary approach to provide the best medical care to the victims

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

Blackbody emission from light interacting with an effective moving dispersive medium

Intense laser pulses excite a nonlinear polarisation response that may create an effective flowing medium and, under appropriate conditions, a blocking horizon for light. Here we analyse in detail the interaction of light with such laser-induced flowing media, fully accounting for the medium dispersion properties. An analytical model based on a first Born-approximation is found to be in excellent agreement with numerical simulations based on Maxwell's equations and shows that when a blocking horizon is formed, the stimulated medium scatters light with a blackbody emission spectrum. Based on these results, diamond is proposed as a promising candidate medium for future studies of Hawking emission from artificial, dispersive horizons

The ATLAS Simulation: an LHC Challenge

The simulation program for the ATLAS experiment at CERN is currently in a full operational mode and integrated into the ATLAS common analysis framework, Athena. The OO approach, based on GEANT4, and in use during the DC2 data challenge has been interfaced within Athena and to GEANT4 using the LCG dictionaries and Python scripting. The robustness of the application was proved during the DC2 data challenge. The Python interface has added the flexibility, modularity and interactivity that the simulation tool requires in order to be able to provide a common implementation of different full ATLAS simulation setups, test beams and cosmic ray applications. Generation, simulation and digitization steps were exercised for performance and robustness tests. The comparison with real data has been possible in the context of the ATLAS Combined Test Beam (2004) and ongoing cosmic ray studies