The Acute Toxicity of Mineral Fibres: A Systematic In Vitro Study Using Different THP-1 Macrophage Phenotypes

Alveolar macrophages are the first line of defence against detrimental inhaled stimuli. To date, no comparative data have been obtained on the inflammatory response induced by different carcinogenic mineral fibres in the three main macrophage phenotypes: M0 (non-activated), M1 (pro-inflammatory) and M2 (alternatively activated). To gain new insights into the different toxicity mechanisms of carcinogenic mineral fibres, the acute effects of fibrous erionite, crocidolite and chrysotile in the three phenotypes obtained by THP-1 monocyte differentiation were investigated. The three mineral fibres apparently act by different toxicity mechanisms. Crocidolite seems to exert its toxic effects mostly as a result of its biodurability, ROS and cytokine production and DNA damage. Chrysotile, due to its low biodurability, displays toxic effects related to the release of toxic metals and the production of ROS and cytokines. Other mechanisms are involved in explaining the toxicity of biodurable fibrous erionite, which induces lower ROS and toxic metal release but exhibits a cation-exchange capacity able to alter the intracellular homeostasis of important cations. Concerning the differences among the three macrophage phenotypes, similar behaviour in the production of pro-inflammatory mediators was observed. The M2 phenotype, although known as a cell type recruited to mitigate the inflammatory state, in the case of asbestos fibres and erionite, serves to support the process by supplying pro-inflammatory mediators.     

Measurements of monomer partitioning in emulsion copolymerization systems

A new apparatus to measure the equilibrium solvent activity in a multiphase system containing a particulated polymer is presented. An experimental procedure to determine the monomer partitioning in typical emulsion copolymerization systems is developed; the method is devised in a way that no phase separation between water and swollen polymer particles is required in order to determine the monomer content in each phase. The analytical technique used is quantitative gas chromatography, either of the vapor or of the liquid phases. Different monomers (styrene, methyl methacrylate, and vinyl acetate) and polymeric matrices (polystyrene and methyl methacrylate–vinyl acetate copolymer) are examined both above and below saturation conditions (corresponding to intervals II and III of an emulsion polymerization process). The experimental results are compared with predictions of a literature model. © 1996 John Wiley & Sons, Inc.     

Carbon NanoTubes as suitable platform to signals recording of cardiac cells interfaced to metal microelectrodes: a modeling approach

Monitoring the electrophysiology of living cells by micro/nano devices is a well-established technique in a large area of biomedical applications. The main fascination is the ability of these devices to perform, in real-time, non-invasive investigations of the physiological state of a cell population. In this work, we present a hybrid microsystem model to detect extracellular signals induced by cardiac cells (CDs). In particular, the bio-electronic junction established by interfacing cardiac cells to Carbon NanoTubes (CNTs) vertically grown on the surface of a metal microelectrode (MIC) was modeled to analyze the induced extracellular cell electrical activity. The simulation results strengthened the assumptions that CNTs, as electrical interfaces, enhance the amplitude and act on the shape of the recorded extracellular signals, compared to other microelectrode substrates.     

Cyclodextrin Insulation Prevents Static Quenching of Conjugated Polymer Fluorescence at the Single Molecule Level

Conjugated polymers (CPs) are promising materials for fluorescence imaging application. However, a significant problem in this field is the unexplained abnormally low fluorescence brightness (or number of fluorescence photons detected per one excitation photon) exhibited by most of CP single chains in solid polymer hosts. Here it is shown that this detrimental effect can be fully avoided for short chains of polyfluorene‐bis‐vinylphenylene (PFBV) embedded in a host polymer matrix of PMMA, if the conjugated backbone is insulated by cyclodextrin rings to form a polyrotaxane (PFBV‐Rtx). Fluorescence kinetics and quantum yields are measured for the polymers in liquid solutions, pristine films, and solid PMMA blends. The fluorescence brightness of PFBV‐Rtx single chains dispersed in a solid PMMA is very close to that expected for a chain with 100% fluorescence quantum yield, while the unprotected PFBV chains of the same length possess 4 times lower brightness. Despite this, the fluorescence decay kinetics are the same for both polymers, suggesting the presence of static or ultrafast fluorescence quenching in the unprotected polymer. About 80% of an unprotected PFBV chain is estimated to be completely quenched. The hypothesis is that the cyclodextrin rings prevent the quenching by working as ‘bumpers’ reducing the mechanical forces applied by the host polymer to the conjugated backbone and help retaining its conformational freedom. While providing a recipe for making CP fluorescence bright at the single‐molecule level, these results identify a lack of fundamental understanding in the community of the influence of the environment on excited states in conjugated materials.     

A general framework for modeling long-term behavior of earth and concrete dams

Many problems are linked with the long-term behavior of both earthdams and concrete dams. They range from hydraulic fracturing to alkali-silica reaction (ASR) and to repair work in concrete dams, from seismic behavior to secondary consolidation in earthdams. A common framework for the simulation of such systems is shown, based on the mechanics of multiphase porous media. The general model is particularized to specific situations and several examples are shown.     

Rapid HPLC/DAD/MS method to determine phenolic acids,glycoalkaloids and anthocyanins in pigmented potatoes (Solanum tuberosum L.) and correlations with variety and geographical origin

In the present study a single procedure to simultaneously determine phenolic acids, anthocyanins and glycoalkaloids was applied in 13 cultivars all with pigmented peel. A single exhaustive extraction for the three classes of compounds and a single analytical HPLC method were proposed. From a quantitative point of view, the RSD values from intra and inter-day assays were <5.7% for the three classes of metabolites. Concerning the influence of different growing areas, the highest anthocyanin concentrations and the lower glycolkaloid content in the pulp were found in tubers from the geographical area at 1000 m a.s.l in southern Italy. Principal Component Analysis (PCA) did not allow the discrimination of different clusters when applied to phenolic acids, while the scatterplot obtained with regard to the anthocyanin profiles clustered the cultivars into five distinct groups. These pigments can be proposed as “fingerprints” of the cultivar.     

Energy retrofit of historical buildings: theoretical and experimental investigations for the modelling of reliable performance scenarios

The paper suggests a multi-criteria approach for the energy refurbishment of historical buildings, proposing methodologies for the performance analysis, coupling several experimental and numerical studies. The target consisted in a rigorous evaluation procedure, in order to guarantee the necessary reliability of a numerical model of the system “building envelope/technical plants”, on which testing the technical and economical convenience of energy retrofit solutions.The paper collects the long work carried out by several Institutions during the last years, on Building “Palazzo dell’Aquila Bosco-Lucarelli”, a historical building located in Benevento (Southern Italy), currently analyzed in order to define the technical adoption of possible improving actions.The carried out studies, beyond the proposition of an operational methodology, are aimed to evidence a best-practice specified for the Italian territorial context, which has several historical buildings needing restoration.Carefully applied investigations, based on various methodologies and through several instrumentations, allowed the definition of a numerical model correspondent to the real building, defined also comparing the results with the historical requests of gas and electricity. Moreover, dynamic energy simulations tested the effectiveness, singularly and coupled, of several solutions for the building energy optimization. A significant potentiality of energy and economic optimization has been demonstrated.     

Fabrication of miniaturized Si-based electrocatalytic membranes

The increasing interest for lightweight and portable electronic systems, cellphones and small digital devices is driving technological research towards integrated regenerating power sources with small dimensions and great autonomy. Conventional batteries are already unable to deliver power in ever smaller volumes while maintaining the requirements of long duration and light weight. A possible solution to overcome these limits is the use of miniaturized fuel cells. The fuel cell offers a greater gravimetric energy density compared to conventional batteries. The micromachining technology of silicon is an important tool to reduce the fuel cell structure to micron sizes. The use of silicon also gives the opportunity to integrate the power source and the electronic circuits controlling the fuel cell on the same structure. This article reports preliminary results concerning the micromachining process for fabricating a silicon-based electrocatalytic membrane for miniaturized Si-based proton-exchange membrane (PEM) fuel cells.