X-ray photoelectron spectroscopy investigation of nanoporous NiO electrodes sensitized with Erythrosine B

Nanoporous NiO thin films were prepared onto FTO glass substrates by means of screen-printing and were sensitized with Erythrosine B (EryB) dye. The obtained material was electrochemically treated and characterized with ex-situ X-ray photoelectron spectroscopy in order to gain information beneficial to the application of sensitized NiO as photocathodes of p-type dye-sensitized solar cells (p-DSCs). In particular, EryB-sensitized NiO films underwent a series of electrochemical treatments in LiClO4/Acetonitrile (ACN) electrolyte devised so as to simulate possible conditions the electrode might encounter during operation in the photoelectrochemical cell. Upon potential-cycling in a range where the two NiO faradic events Ni(II)→Ni(III) and Ni(III)→Ni(IV) occur, X-ray photoelectron spectroscopy revealed that Erythrosine B dye experiences a partial detachment from the NiO surface. This detachment seems to be paralleled by the formation of stable (Ni)+(ClO4)- couples. Overall, the EryB dye displayed an acceptable electrochemical stability onto the surface of NiO electrode up to 50 cyclic voltammetries in the range -0.27÷+1.13V vs. Ag/AgCl. These results are useful for the evaluation of electrochemical stability of the dye when this is immobilized onto an electrode surface and are beneficial for a better comprehension of the degradation phenomena operating in real photoconversion device. © 2017 Elsevier B.V

Effect of sodium hydroxide pretreatment of NiOx cathodes on the performance of squaraine-sensitized p-type dye-sensitized solar cells

Squaraines are full-organic dyes employed as sensitizers in ptype dye-sensitized solar cells (p-DSSC). Their absorption spectrum shows a wide tunability that ranges from visible to NIR. Sensitization in the NIR region is crucial for exploiting a particularly intense portion of the solar spectrum. In this work three squaraines will be presented and tested as sensitizers in NiO-based p-type DSSC O4_C2, O4_C4 and O4_C12). The structures of the dyes differ for the length of the alkyl side chain (C2, C4 and C12). Alkyl side chains improve the solubility of the dye, influence the extent of dye loading on the electrode and affect the overall efficiency of devices. The generally low stability of squaraines represents a critical issue in view of their employment as sensitizers of p-DSSC. Such a problem becomes even more evident when this class of molecules is bound onto an acidic surface like the one of the photocathode here employed: non-stoichiometric nickel oxide (NiOx). NiOx possesses a quite acidic character because of the high surface concentration of Ni(III) sites. To buffer the surface acidity of NiOx due to the presence of high-valence states of nickel, we considered the electrode pretreatment with sodium hydroxide (NaOH) prior to sensitization. This assures a major stability of the solar cell. At the same time the chemisorbed hydroxyl moieties act as passivating agents of the Ni(III) sites thus diminishing the surface concentration of sites for dye anchoring. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

mixed mode crack propagation during needle penetration for surgical interventions

Abstract An accurate description of the penetration mechanics of flexible needles into target soft tissues is a complex task, including friction at the needle-tissue interface, large strains, non-predetermined penetration trajectories, fracture under mixed-mode loading and so on. In the present work, a finite element algorithm is employed to simulate the two-dimensional deep penetration of a flexible needle in a soft elastic material. The fracture process of the target material during penetration is described by means of a cohesive zone model, with a suitable mixed-mode criterion for determining the propagation direction of the crack. To illustrate the potential of the numerical algorithm, we have performed some simulations of the insertion of a flexible needle with an asymmetric tip, and the results are presented in terms of force-penetration curves as well as of the obtained penetration paths in the target tissue

Reverse telescoping in a distal skarn system (Campiglia Marittima, Italy)

The Campiglia Marittima Fe-Cu-Zn-Pb(-Ag) skarn deposit has long been regarded as a reference example of an exoskarn showing a symmetric outward mineralogical zoning of both skarn and ore minerals with respect to an axial mafic porphyry dike. Detailed field and underground mapping, along with three-dimensional reconstruction of the geometries of skarn and magmatic bodies, integrated with new petrographic, mineralogical and geochemical data, argue against this model. The shapes of the skarn bodies and the growth versors of skarn minerals in particular, are ascribed to the focusing of metasomatic fluids in sigmoid-shaped volumes of fractured host marble. After skarn formation, a mafic magma was emplaced, forming dikelets and filling residual pockets in the skarn. Field evidence and geochemical data show that the "hot" mafic magma interacted with the previously formed Zn-Pb(-Ag) skarn, triggering textural reworking and chemical redistribution of Zn-Pb sulfides as well as contributing to a late Fe-Cu mineralization. Campiglia Marittima skarn-ore system behaved at odd: a telescoping process is recorded, yet in a reverse way

Validation of a rapid test to dose SO2 in vinegar

Sulfur dioxide is generally used in wine and vinegar production. It is employed to decrease the bacteria' growth, improve the wines' aroma (since it supports the extraction of polyphenols during maceration), protect the wines from chemical oxidation and the musts from chemical and enzymatic oxidation (blocking free radicals and oxidase enzymes such as tyrosinase and laccase). The composition and storage conditions (i.e., pH, temperature, and alcohol levels) affect oenological results. In various countries, competent authorities have imposed legal limits since it can have toxic effects on humans. It is crucial to dose SO2 levels to allow vinegar production and compliance with legal limits. The iodometric titration named "Ripper test" is the legal method used to dose it in vinegar. In this work, an automatized colorimetric test was validated using the international guidelines ISO/IEC (2017) to allow its use instead of the Ripper test. The test reliability was verified on white, red, and balsamic vinegar with low or high SO2 content. The automatized test showed linearity, precision, and reproducibility similar to the Ripper test, but the accuracy parameter was not respected for the vinegar with a low concentration of SO2. Therefore, the automatized colorimetric test can be helpful to dose SO2 in vinegar with high concentrations of SO2

MADAM: Effective and Efficient Behavior-based Android Malware Detection and Prevention

Android users are constantly threatened by an increasing number of malicious applications (apps), generically called malware. Malware constitutes a serious threat to user privacy, money, device and file integrity. In this paper we note that, by studying their actions, we can classify malware into a small number of behavioral classes, each of which performs a limited set of misbehaviors that characterize them. These misbehaviors can be defined by monitoring features belonging to different Android levels. In this paper we present MADAM, a novel host-based malware detection system for Android devices which simultaneously analyzes and correlates features at four levels: kernel, application, user and package, to detect and stop malicious behaviors. MADAM has been designed to take into account those behaviors characteristics of almost every real malware which can be found in the wild. MADAM detects and effectively blocks more than 96% of malicious apps, which come from three large datasets with about 2,800 apps, by exploiting the cooperation of two parallel classifiers and a behavioral signature-based detector. Extensive experiments, which also includes the analysis of a testbed of 9,804 genuine apps, have been conducted to show the low false alarm rate, the negligible performance overhead and limited battery consumption

Fluorescent Light Energy in the Management of Multi Drug Resistant Canine Pyoderma: A Prospective Exploratory Study

The increase in prevalence of staphylococcal antimicrobial resistance has been also associated with pyoderma in dogs, and prolonged antibiotic treatment, as often needed in severe cases of pyoderma, has been related to influencing possible development of multidrug resistance (MDR). Fluorescent light energy (FLE) has been indicated to improve pyoderma lesions as adjunct therapy to systemic antibiotics. In the present study, we evaluated the effect of FLE on clinical signs of MDR canine deep pyoderma (CDP) and interdigital furunculosis (CIF) when administered as solely management. Sixteen client-owned dogs affected by CIF (five dogs) and CDP (eleven dogs) were scored using a dedicated scoring system and received a single FLE applications twice weekly, until clinical resolution was achieved. Mean time to achieve complete resolution was 5.20 3.56 weeks (median 3 weeks) for CIF cases and 4.18 1.47 weeks (median 4 weeks) for CDP ones. FLE shows promise as an aid to managing clinical signs while reducing reliance on antibiotics for MDR CDP and CIF. In this study, FLE was responsible for the decrease in lesion scores and resolution of MDR pyoderma infection without any adjunct therapy, having a potential useful role to play in antibiotic stewardship programs, efficiently promoting complete clinical resolution of MDR lesions while optimizing the use of antibiotics

Mobile underwater sensor networks for protection and security: field experience at the UAN11 experiment

An underwater acoustic network (UAN) represents a communication infrastructure that canoffer the necessary flexibility for continuous monitoring and surveillance of critical infras-tructures located by the sea. Given the current limitation of acoustic-based communicationmethods, a robust implementation of UANs is still an open research field. The FP7 UANproject addressed such a problem, and it reached the integration of a mobile underwatersensor network within a wide-area network, which included above water and underwatersensors, for protection and security. This paper describes some of the main results achievedduring the project. In particular, this work addresses solutions for the upper-layers of theUAN, with focus on the integration of autonomous underwater vehicles (AUVs) as mobilenodes of the network, and on the inclusion of network security mechanisms. The recent at-sea successes that have been demonstrated within the UAN framework are detailed. Resultsare given of the final UAN project demonstration, UAN11, held in the May of 2011, whenan underwater acoustic network composed by four fixed nodes, two autonomous underwa-ter vehicles (AUVs), and one mobile node mounted on the supporting research vessel, wascontinuously operated for one week, and integrated into a global protection system

Laser machining of glass microreactors: a first experimental study

The use of microreactors is one of the latest innovations in the chemical and pharmaceutical industry. One of the main issues in the fabrication of microreactors is the use of a proper technique to obtain the micro channels, in order to give them the desired shape and section so that reactants flowing inside are correctly fed through inlet branches and mixed. This paper proposes an experimental study on glass machining for the fabrication of microreactor channels through the use of a CO2 laser source. The aim of the experiments is to analyse the effects of a CO2 laser beam on glass and to study the influence of process parameters, such as laser power, focal distance and scanning speed, on the shape of the channel section and on the surface finish