Optical and electrical characterization of a gold nanoparticle dispersion in a chiral liquid crystal matrix

We report on the effect of gold nanoparticle (Au NP) dispersion in a chiral nematic liquid crystal (LC). Polarized optical microscopy and X-ray diffraction measurements evidence the insurgence of an order change in the LC host. Moreover, a comparative analysis based on dielectric and voltammetric spectroscopies performed on pure LC and on Au NP-doped LC shows that Au NP’s presence besides affecting LC order influences its electric properties: ion conductivity results importantly reduced, and beyond a threshold value of the applied field electrophoresis phenomena are induced.     

Detection of glyphosate and its metabolites in food of animal origin based on ion-chromatography-high resolution mass spectrometry (IC-HRMS)

Glyphosate and glufosinate are broad spectrum herbicides, widely used in agriculture and in inhabited or industrialised areas, and aminomethylphosphonic acid is a degradation product of glyphosate. In 2015, the International Agency for Research on Cancer reported that glyphosate is a probable carcinogenic. In 2017, however, a scientific opinion of the European Chemicals Agency concluded that glyphosate is not proven to be carcinogenic, mutagenic or to have negative effects on reproduction. Nevertheless, aminomethylphosphonic acid was not considered. Due to their chemical-physical characteristics, these molecules present difficulties that have not yet allowed routine monitoring to be carried out. For these reasons, we developed and validated a simple and versatile liquid extraction, before IC-HRMS analysis, of three different complex matrices: honey, bass fish and bovine muscle. Among the satisfactory validation parameters, the LOQs in the range of 4.30–9.26 ng g^?1 demonstrated high method sensitivity, compared to the few works present in literature. Finally, the method was applied to real commercial samples, which showed no traces of the selected pesticides.     

Sensitivity Analysis and Model Validation of a 2-DoF Mini Spherical Robot

This paper is focused on the development and validation of an error kinematic model of a mini spherical robot, aimed at its kinematic calibration. The robot is actually a spatial five-bar linkage, provided with two rotational degrees of freedom. A non-overconstrained kinematics is assumed for the robot in order to provide a simple mathematical model and allow a sensitivity analysis of all the involved geometric parameters. A simplified version of the model is proposed. It differs only for the degree of approximation. A comparison between full and reduced models is presented by means of numerical simulations, analyzing their behavior in a significant region of the robot workspace. In order to validate both of them a robot calibration is carried out on a physical prototype of the robot using a vision system, namely a fixed camera in a eye-to-hand configuration. An iterative algorithm aimed at the experimental identification of the geometric data of the robot is used. Some experimental results show the effectiveness of the study.     

Characterization, modeling and assessment of Roll-N-Cage isolator using the cable-stayed bridge benchmark

This paper presents the results of an extensive series of simulation tests to identify the mechanical characteristics of an innovative isolation device known as the Roll-N-Cage (RNC) isolator. The seismic performance of an RNC passive control scheme is subsequently investigated on a model of the cable-stayed bridge benchmark. Starting from different configurations studied in the laboratory for a 1/10 reduced-scale prototype, the RNC isolator stiffness and damping properties are investigated in terms of cyclic tests with different parameters. Tests at the ultimate level state consisting of monotonic shear and axial loading have been also carried out as a part of the qualification process. The goal of this study is twofold: first, to examine the main integrated mechanisms of the RNC isolator through sophisticated 3D finite element simulation models using a multi-purpose finite element code. The main result of this step is to attempt modeling the force–displacement relationship using the standard Bouc–Wen model of smooth hysteresis. The second aim of this study is the numerical assessment of the device efficiency through its implementation into a bridge model considering several ground motions as external excitations. Based on these extensive studies, it was found that the RNC isolator is promising as a reliable isotropic horizontal isolation device for bridge structures.     

Parametric cost analysis for web-based e-commerce of layer manufactured objects

Web-based e-commerce of rapid prototyping services is going to be a widely diffused methodology used to compete in a global market. A competitive market imposes a very accurate estimation of prototyping price. Prototype costs depend on many factors, some of which may be easily deduced, while some others consist in a complex function of the geometric model properties and of the specific technology employed to build a physical model. Build time, which affects some components of the prototype's build cost, is a critical factor to deduce. Build time depends not only on the prototype dimensions but also on the complexity of the shape that, in turn, affects the movement of the tool to form the object. A parametric approach to build cost estimation, suited for web-based e-commerce, is presented in this paper. Significant cost driving factors of layer manufactured objects are identified and instruments to evaluate them are proposed. Special attention has been paid to define a parametric approach to build time estimation. The proposed parametric approach analyses the geometrical features, which typically affect the build time of the main layer manufacturing technologies. The method is verified in some test cases related to FDM technology.     

A Phenylacetamide Resveratrol Derivative Exerts Inhibitory Effects on Breast Cancer Cell Growth

Resveratrol (RSV) is a natural compound that displays several pharmacological properties, including anti-cancer actions. However, its clinical application is limited because of its low solubility and bioavailability. Here, the antiproliferative and anti-inflammatory activity of a series of phenylacetamide RSV derivatives has been evaluated in several cancer cell lines. These derivatives contain a monosubstituted aromatic ring that could mimic the RSV phenolic nucleus and a longer flexible chain that could confer a better stability and bioavailability than RSV. Using MTT assay, we demonstrated that most derivatives exerted antiproliferative effects in almost all of the cancer cell lines tested. Among them, derivative 2, that showed greater bioavailability than RSV, was the most active, particularly against estrogen receptor positive (ER+) MCF7 and estrogen receptor negative (ER-) MDA-MB231 breast cancer cell lines. Moreover, we demonstrated that these derivatives, particularly derivative 2, were able to inhibit NO and ROS synthesis and PGE2 secretion in lipopolysaccharide (LPS)-activated U937 human monocytic cells (derived from a histiocytoma). In order to define the molecular mechanisms underlying the antiproliferative effects of derivative 2, we found that it determined cell cycle arrest at the G1 phase, modified the expression of cell cycle regulatory proteins, and ultimately triggered apoptotic cell death in both breast cancer cell lines. Taken together, these results highlight the studied RSV derivatives, particularly derivative 2, as promising tools for the development of new and more bioavailable derivatives useful in the treatment of breast cancer.     

Evaluation of 4-(4-Fluorobenzyl)piperazin-1-yl]-Based Compounds as Competitive Tyrosinase Inhibitors Endowed with Antimelanogenic Effects

There is a considerable attention for the development of inhibitors of tyrosinase (TYR) as therapeutic strategy for the treatment of hyperpigmentation disorders in humans. Continuing in our efforts to identify TYR inhibitors, we describe the design, synthesis and pharmacophore exploration of new small molecules structurally characterized by the presence of the 4-fluorobenzylpiperazine moiety as key pharmacophoric feature for the inhibition of TYR from Agaricus bisporus (AbTYR). Our investigations resulted in the discovery of the competitive inhibitor [4-(4-fluorobenzyl)piperazin-1-yl]-(3-chloro-2-nitro-phenyl)methanone 26 (IC₅₀=0.18 μM) that proved to be ∼100-fold more active than reference compound kojic acid (IC₅₀=17.76 μM). Notably, compound 26 exerted antimelanogenic effect on B16F10 cells in absence of cytotoxicity. Docking analysis suggested its binding mode into AbTYR and into modelled human TYR.     

The Interplay between HGF/c-met Axis and Nox4 in BRAF Mutated Melanoma

Background: Melanoma is the leading cause of death due to cutaneous malignancy and its incidence is on the rise. Several signaling pathways, including receptor tyrosine kinases, have a role in the development and progression of melanocytic lesions and malignant melanoma. Among those, the hepatocyte growth factor (HGF)/c-met axis is emerging as a critical player because it can play a role in drug resistance. Indeed, 50% of melanoma patients present BRAF mutations, however, all responders develop resistance to the inhibitors typically within one year of treatment. Interestingly, BRAF inhibitors induce reactive oxygen species (ROS) in melanoma cells, therefore, the aim of this study was to investigate a possible interplay between HGF/c-met and ROS sources, such as NADPH oxidases (Nox). Methods: The expression of c-met and Nox were quantified in 60 patients with primary cutaneous melanoma. In vitro experiments on melanoma primary cells and the cell line were performed to dissect the underpinned molecular mechanism. Results: The outcome of interest was the correlation between the high positivity for both Nox4 and c-met and metastasis occurring at least 1 year later than melanoma diagnosis in BRAF mutated patients, in contrast to nonmutated. In vitro experiments demonstrated that the axis HGF/c-met/Nox4/ROS triggers the epithelial-mesenchymal transition. Conclusions: The observed correlation suggests an interplay between c-met and Nox4 in promoting the onset of metastasis. This study suggests that Nox4 inhibitors could be associated to the current therapy used to treat melanoma patients with BRAF mutations.     

The Metabolic Role of Gut Microbiota in the Development of Nonalcoholic Fatty Liver Disease and Cardiovascular Disease

The prevalence of metabolic disorders, such as type 2 diabetes (T2D), obesity, and non-alcoholic fatty liver disease (NAFLD), which are common risk factors for cardiovascular disease (CVD), has dramatically increased worldwide over the last decades. Although dietary habit is the main etiologic factor, there is an imperfect correlation between dietary habits and the development of metabolic disease. Recently, research has focused on the role of the microbiome in the development of these disorders. Indeed, gut microbiota is implicated in many metabolic functions and an altered gut microbiota is reported in metabolic disorders. Here we provide evidence linking gut microbiota and metabolic diseases, focusing on the pathogenetic mechanisms underlying this association.