Effect of particle size on pigments colour

The historical pigments, contrary to modern ones, are not constituted by particles having all the same size and this influences the colour of the paint layers. The hiding power and colouring power of a pigment depends, in fact, on its particle size. The aim of this study was to evaluate the influence of particle size on optical characterization of paintings in terms of reflection of light and related colour specification. Starting from the qualitative observation, we have attempted to quantify the pigments colour variations induced by grinding and then attributable to granularity. Powdered pigments of principal colours have been selected in specific particle size range by mechanical sieving. The measurements were performed both on pigment pellets and on paintings realized with binder casein. All samples were characterized by an optical and colorimetric point of view through spectrophotometric analysis and for the surface morphological observation through scanning electron microscopy. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 236–243, 2017     

Immunohistochemical study on the prognostic value of the expression of laminin and Ki-67 receptors in advanced gastric cancer

The expression of 67-KDa laminin receptor (LR) was investigated in a group of 75 patients who underwent curative gastrectomy for advanced gastric cancer, with special reference to the possible role in the tumor progression and in the overall survival. In 56 out of these 75 patients also the prognostic significance of proliferative activity was investigated using the monoclonal antibody Ki-67. The tumor LR expression and the Ki-67 labeling index (Ki-67 LI) were immunohistochemically determined in paraffin-embedded sections using the avidin-biotin immunoperoxidase method. The cumulative 5-years survival rate was 75.1% for patients without expression of LR, 52.6% for those with positive LR expression. Significant association between LR expression and depth of tumor invasion (p = 0.022) was found. By univariate analysis the presence of laminin receptor seemed to be associated with an higher risk of death (RR1.73-95% C.I. 0.71-4.20), but this effect disappeared after controlling for depth of tumor invasion. There was no significant relationship between the Ki-67 LI and wall invasion (p = 0.80) or nodal status (p = 0.73). The cumulative 5-year survival rates (95% CI) were 61.0% (35.3-79.2) in patients with Ki-67 index < 10%, 52.4% (29.7-70.9) with Ki-67 index = 10%-40%, 52.9% (27.6-73.0) with Ki-67 index > 40% and the differences were not statistically significant (p = 0.93). Also in multivariate analysis the proliferative activity did not independently affect survival (p = 0.98). An interaction between Ki-67 index and age was found and Ki-67 index > 40% was significantly associated with a poor prognosis in patients over 70 years old old (p = 0.002). In conclusion, tumor expression of laminin receptor could be correlated with gastric cancer aggressiveness, however its prognostic significance is already provided by depth of tumor invasion. The proliferative activity, determined with the monoclonal antibody Ki-67, does not seems to influence the survival except in elderly patients (> or = 70 years old).     

A probabilistic framework for multidisciplinary design: Application to the hydrostructural optimization of supercavitating hydrofoils

The analysis and optimization of complex multiphysics systems presents a series of challenges that limit the practical use of computational tools. Specifically, the optimization of such systems involves multiple interconnected components with competing quantities of interest and high‐dimensional spaces and necessitates the use of costly high‐fidelity solvers to accurately simulate the coupled multiphysics. In this paper, we put forth a data‐driven framework to address these challenges leveraging recent advances in machine learning. We combine multifidelity Gaussian process regression and Bayesian optimization to construct probabilistic surrogate models for given quantities of interest and explore high‐dimensional design spaces in a cost‐effective manner. The synergistic use of these computational tools gives rise to a tractable and general framework for tackling realistic multidisciplinary optimization problems. To demonstrate the specific merits of our approach, we have chosen a challenging large‐scale application involving the hydrostructural optimization of three‐dimensional supercavitating hydrofoils. To this end, we have developed an automated workflow for performing multiresolution simulations of turbulent multiphase flows and multifidelity structural mechanics (combining three‐dimensional and one‐dimensional finite element results), the results of which drive our machine learning analysis in pursuit of the optimal hydrofoil shape.     

Multicentre survey of the comparative in-vitro activity of piperacillin/tazobactam against bacteria from hospitalized patients in the British Isles

In five experiments, in which subjects were to identify a target word as it was gradually clarified, we manipulated the target's frequency of occurrence in the language and its neighborhood size--the number of words that can be constructed from a target word by changing one letter, while preserving letter position. In Experiments 1-4, visual identification performance to screen-fragmented words was measured. In Experiments 1 and 2, we used the ascending method of limits, whereas Experiments 3 and 4 presented a fixed-level fragment. In Experiment 1, there was no relation between overall accuracy and neighborhood size for words between three and six letters in length. However, more errors of commission (guesses) were made for high-neighborhood words and more errors of omission (blanks) were made for low-neighborhood words. Letter errors within guesses occurred at serial positions having many neighbors, and these positions were also likely to contain consonants rather than vowels. In Experiment 2, a small facilitatory effect of neighborhood size on both high- and low-frequency words was found. In contrast, in Experiments 3 and 4, using the same set of words, inhibitory effects of neighborhood size, but only for low-frequency words, were found. Experiment 5, using a speeded identification task, showed results parallel to those of Experiments 3 and 4. We suggest that whether neighborhood effects are facilitatory or inhibitory depends on whether feedback allows subjects to disconfirm initial hypotheses that the target is a high-frequency neighbor.     

The Paradox Effect of Calcification in Carotid Atherosclerosis: Microcalcification Is Correlated with Plaque Instability

Background: this study aims to investigate the possible association among the histopathologic features of carotid plaque instability, the presence of micro- or macrocalcifications, the expression of in situ inflammatory biomarkers, and the occurrence of the major risk factors in this process in a large series of carotid plaques. Methods: a total of 687 carotid plaques from symptomatic and asymptomatic patients were collected. Histological evaluation was performed to classify the calcium deposits in micro or macrocalcifications according to their morphological features (location and size). Immunohistochemistry was performed to study the expression of the main inflammatory biomarkers. Results: results here reported demonstrated that calcifications are very frequent in carotid plaques, with a significant difference between the presence of micro- and macrocalcifications. Specifically, microcalcifications were significantly associated to high inflamed unstable plaques. Paradoxically, macrocalcifications seem to stabilize the plaque and are associated to a M2 macrophage polarization instead. Discussion: the characterization of mechanisms involved in the formation of carotid calcifications can lay the foundation for developing new strategies for the management of patients affected by carotid atherosclerosis. Data of this study could provide key elements for an exhaustive evaluation of carotid plaque calcifications allowing to establish the risk of associated clinical events.     

Inkjet printing of transparent, flexible, organic transistors

Two different types of all-organic, transparent transistors, namely Organic Thin Film Transistors (OTFTs) and Organic Electrochemical Transistors (OECTs), were fabricated on transparent, flexible plastic substrates by means of inkjet printing. In OTFTs the source, drain and gate electrodes were inkjet printed using a poly(3,4ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS ) solution, while a thermally sublimated layer of Parylene C acted as gate dielectric. Two kinds of organic semiconductors were used as active layers: 6,13-bis(triisopropylsilylethynyl) pentacene for p-type and N1400 for n-type OTFTs. For OECTs, all electrodes were also realized by inkjet printing deposition of a PEDOT:PSS solution. Electrical output characteristics of both kinds of devices are reported, demonstrating that the performances of our devices may be compared to those of transistors fabricated employing different realization techniques.     

A different approach to the analysis of data in life-tests of laser diodes

A different reading of the available I–V curves is proposed for laser diodes whose characteristics display some degradation. In particular, the usual monitoring of the optical power P and of the threshold current I_th is complemented by the inspection of two more parameters, which separately or jointly contribute to the general variation of I_th. These two parameters are related to the simplest laser model, made of an ideal diode that is voltage-clamped under operating conditions, and are completely defined by those same standard measurements that lead to evaluate I_th. A different definition of the failure modes, and a deeper insight in the possible failure mechanisms are derived. Combined voltage and optical power monitoring during constant-current life-tests is also proposed as a more discriminating measurement than usually considered.     

Organic field effect transistors for textile applications.

In this paper, several issues concerning the development of textiles endowed with electronic functions will be discussed. In particular, issues concerning materials, structures, electronic models, and the mechanical constraints due to textile technologies will be detailed. The idea starts from an already developed organic field-effect transistor that is realized on a flexible film that can be applied, after the assembly, on whatever kind of substrate, in particular, on textiles. This could pave the way to a variety of applications aimed to conjugate the favorable mechanical properties of textiles with the electronic functions of transistors. Furthermore, a possible perspective for the developments of organic sensors based on this structure are described.     

High performance,foldable, organic memories based on ultra-low voltage,thin film transistors

We report on the fabrication of highly flexible OTFT-based memory elements with excellent mechanical stability and high retention time. The devices have been fabricated using a combination of two ultrathin AlOx and Parylene C as dielectric, and TIPS-Pentacene as the semiconductor, obtaining high performing low voltage transistors with mobility up to 0.4 cm²/V s, and I_on/I_off ratio of 10⁵. Charge trapping in the Parylene C electret layer is the mechanism that allows employing these devices as non volatile memory elements, with retention time as high as 4 × 10⁵ s. The electromechanical characterization demonstrated that such memory elements can be cyclically bent around a cylinder with a radius of 150 μm without losing the stored data.