Liquid electrolyte positioning along the device channel influences the operation of Organic Electro-Chemical Transistors

In this work, we show the influence of the liquid electrolyte adsorption by porous films made of poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate), PEDOT:PSS, on the operation of an Organic Electro-Chemical Transistor with an active channel based on these polymeric films. In particular, the effect of film hydration on device performance is evaluated by studying its electrical response as a function of the spatial position between the electrolyte and the channel electrodes. This is done by depositing a PEDOT:PSS film on a super-hydrophobic surface aimed at controlling the electrolyte confinement next to the electrodes. The device response shows that the confinement of ionic liquids near to the drain electrode results in a worsening of the current modulation. This result has been interpreted in the light of studies dealing with the transport of ions in semiconducting polymers, indicating that the electrolyte adsorption by the polymeric film implies the formation of liquid pathways inside its bulk. These pathways, in particular, affect the device response because they are able to assist the drift of ionic species in the electrolyte towards the drain electrode. The effect of electrolyte adsorption on the device operation is confirmed by means of moving-front measurements, and is related to the reproducibility of the device operation curves by measuring repeatedly its electrical response.     

Advanced microstructural characterization of plasma-sprayed zirconia coatings over extended length scales

Achieving control of the microstructure of plasma-sprayed thermal barrier coating (TBC) systems offers an opportunity to tailor coating properties to demanding applications. Accomplishing this requires a fundamental understanding of the correlations among processing, microstructure development, and related TBC properties. This article describes the quantitative characterization of the microstructure of plasma-sprayed partially stabilized zirconia (PSZ) coatings by means of x-ray and neutron-scattering imaging techniques. Small-angle neutron scattering, ultra-small-angle x-ray scattering, and x-ray microtomography were used to characterize and visualize the nature and structure of the features in these material systems. In addition, the influence of processing parameters on microstructure development is discussed along with thermal cycling effects on the pore morphology, and their resultant influence of the porosity on the thermal conductivity and elastic modulus of plasma-sprayed PSZ TBCs.     

A Case Study in Embedded Systems Design: An Engine Control Unit

A number of techniques and software toolsfor embedded system design have been recently proposed. However,the current practice in the designer community is heavily basedon manual techniques and on past experience rather than on arigorous approach to design. To advance the state of the artit is important to address a number of relevant design problemsand solve them to demonstrate the power of the new approaches.We chose an industrial example in automotive electronics to validateour design methodology: an existing commercially available EngineControl Unit. We discuss in detail the specification, the implementationphilosophy, and the architectural trade-off analysis. We analyzethe results obtained with our approach and compare them withthe existing design underlining the advantages offered by a systematicapproach to embedded system design in terms of performance anddesign time.     

Effects of free fatty acids on the oxidative processes in purified olive oil

Several studies have investigated the interaction of free fatty acids with the oxidative phenomena involving oils during processing and storage. Nevertheless, the available information is insufficient and, in some cases, contradictory.The aim of this work was to throw light upon this matter, by evaluating – by means of different analytical approaches – the effect of adding increasing amounts of free fatty acids (0.25%, 0.5%, 1%, 3%) on the oxidative processes occurring in purified olive oil during oxidation at 60 °C.The results obtained showed that oxidized forms of triglycerides and polar oligopolymers of triglycerides increased during oxidation. Low amounts of added FFA caused a further increase of the levels of oxidized triglycerides and triglyceride oligopolymers – pointing out a pro-oxidant activity – while higher doses of added free fatty acids lead to lower amounts of oxidized forms of triglycerides respect to the purified oil. This could be due to an increase in peroxide decomposition exerted by free fatty acids when present in higher amounts.     

Skeletal System Biology and Smoke Damage: From Basic Science to Medical Clinic

Cigarette smoking has a negative impact on the skeletal system, as it reduces bone mass and increases fracture risk through its direct or indirect effects on bone remodeling. Recent evidence demonstrates that smoking causes an imbalance in bone turnover, making bone vulnerable to osteoporosis and fragility fractures. Moreover, cigarette smoking is known to have deleterious effects on fracture healing, as a positive correlation between the daily number of cigarettes smoked and years of exposure has been shown, even though the underlying mechanisms are not fully understood. It is also well known that smoking causes several medical/surgical complications responsible for longer hospital stays and a consequent increase in the consumption of resources. Smoking cessation is, therefore, highly advisable to prevent the onset of bone metabolic disease. However, even with cessation, some of the consequences appear to continue for decades afterwards. Based on this evidence, the aim of our review was to evaluate the impact of smoking on the skeletal system, especially on bone fractures, and to identify the pathophysiological mechanisms responsible for the impairment of fracture healing. Since smoking is a major public health concern, understanding the association between cigarette smoking and the occurrence of bone disease is necessary in order to identify potential new targets for intervention.     

A comparison between olive oil and extra-virgin olive oil used as covering liquids in canned dried tomatoes: hydrolytic and oxidative degradation during storage

The hydrolytic and oxidative degradation of olive oil and extra‐virgin olive oil, used as covering liquids in canned dried tomatoes, was studied during storage by means of conventional (acidity, peroxide value, p‐anisidine value) and non conventional (polar compounds) analyses. The effects of the addition of spices were also considered. The hydrolysis and oxidation of olive oil increased faster and was higher than that of extra‐virgin olive oil in terms of absolute values but some other indices, such as percentage of oligopolymers and percentage of oxidized triglycerides, increased faster in extra‐virgin olive oil than in olive oil. The antioxidant effect given by a higher concentration of polyphenols in the extra‐virgin olive oil was shown by a reduced amount of secondary oxidation. However, olive oil and extra‐virgin olive oils showed similar behaviour in terms of peroxide formation.     

Full experimental modelling of a liver tissue mimicking phantom for medical ultrasound studies employing different hydrogels

Tissue mimicking phantoms have been widely reported to be an important tool for development, optimisation and performance testing of ultrasound-based diagnostic techniques. In particular, modern applications of tissue mimicking phantoms often include characterisation of the nonlinear behaviour of experimental ultrasound contrast agents. In such cases, the tissue-mimicking materials should be chosen not only based on the values of their density, speed of sound and attenuation coefficient, but also considering their effect on the appearance of “native harmonics” due to nonlinear distortion of ultrasound signal during propagation. In a previous paper it was demonstrated that a cellulose-based hydrogel is suitable to simulate nonlinear acoustical behaviour of liver tissue for thicknesses up to 8 cm. In this paper we present the experimental characterisation of the nonlinear acoustical behaviour of a different polyethylene glycol diacrylate (PEGDA)-based hydrogel, in order to assess whether and how it can improve the performances and overcome some limitations of the cellulose-based hydrogel as liver tissue-mimicking material. Samples of pig liver tissue, cellulose-based hydrogel and PEGDA-based hydrogel were insonified in a through-transmission set-up, employing 2.25-MHz pulses with different mechanical index (MI) values. Second harmonic and first harmonic amplitudes were extracted from the spectra of received signals and their difference was then used to compare sample behaviours. Obtained results show how a new more accurate and combined experimental model of linear and nonlinear acoustical behaviour of liver tissue is feasible. In fact, a further confirmation of the cellulose-based hydrogel effectiveness to precisely simulate the liver tissue for penetration depths up to 8 cm was provided, and it was also shown that the employment of the PEGDA-based hydrogel can extend the range of useful tissue-mimicking material thicknesses up to 11 cm, moreover allowing a considerable improvement of the time stability and behaviour reliability of the corresponding manufactured phantoms.