Examination of organic coatings on metallic substrates by scanning electrochemical microscopy in feedback mode: Revealing the early stages of coating breakdown in corrosive environments

Scanning electrochemical microscopy in feedback mode was used to monitor changes in the surface state of a polymeric film applied on a metallic substrate when exposed to an aqueous electrolytic environment. The protected metal consisted of a carbon steel substrate coated with a polyurethane-based polymeric film. SECM measurements performed in the presence and absence of chloride anions permitted a specific effect caused by Cl⁻ anions at early exposures to be detected. Significant surface roughening is observed for immersion times shorter than 1 day when the electrolyte contains chloride ions. Additionally, the growth of an individual blister could also be investigated.     

A Hydrogel Platform that Incorporates Laminin Isoforms for Efficient Presentation of Growth Factors – Neural Growth and Osteogenesis

Laminins (LMs) are important structural proteins of the extracellular matrix (ECM). The abundance of every LM isoform is tissue-dependent, suggesting that LM has tissue-specific roles. LM binds growth factors (GFs), which are powerful cytokines widely used in tissue engineering due to their ability to control stem cell differentiation. Currently, the most commonly used ECM mimetic material in vitro is Matrigel, a matrix of undefined composition containing LM and various GFs, but subjected to batch variability and lacking control of physicochemical properties. Inspired by Matrigel, a new and completely defined hydrogel platform based on hybrid LM-poly(ethylene glycol) (PEG) hydrogels with controllable stiffness (1–25 kPa) and degradability is proposed. Different LM isoforms are used to bind and efficiently display GFs (here, bone morphogenetic protein (BMP-2) and beta-nerve growth factor (β-NGF)), enabling their solid-phase presentation at ultralow doses to specifically target a range of tissues. The potential of this platform to trigger stem cell differentiation toward osteogenic lineages and stimulate neural cells growth in 3D, is demonstrated. These hydrogels enable 3D, synthetic, defined composition, and reproducible cell culture microenvironments reflecting the complexity of the native ECM, where GFs in combination with LM isoforms yield the full diversity of cellular processes.     

Natural and hybrid bimanual interaction for virtual assembly tasks

This paper focuses on the simulation of bimanual assembly/disassembly operations for training or product design applications. Most assembly applications have been limited to simulate only unimanual tasks or bimanual tasks with one hand. However, recent research has introduced the use of two haptic devices for bimanual assembly. We propose a more natural and low-cost bimanual interaction than existing ones based on Markerless motion capture (Mocap) systems. Specifically, this paper presents two interactions based on a Markerless Mocap technology and one interaction based on combining Markerless Mocap technology with haptic technology. A set of experiments following a within-subjects design have been implemented to test the usability of the proposed interfaces. The Markerless Mocap-based interactions were validated with respect to two-haptic-based interactions, as the latter has been successfully integrated into bimanual assembly simulators. The pure Markerless Mocap interaction proved to be either the most or least efficient depending on the configuration (with 2D or 3D tracking, respectively). Usability results among the proposed interactions and the two-haptic based interaction showed no significant differences. These results suggest that Markerless Mocap or hybrid interactions are valid solutions for simulating bimanual assembly tasks when the precision of the motion is not critical. The decision on which technology to use should depend on the trade-off between the precision requested to simulate the task, the cost, and inner features of the technology.     

Scanning electrochemical microscopy for the investigation of localized degradation processes in coated metals: Effect of oxygen

The effect of oxygen content on the corrosion reactions inside a holiday in a polymer-coated metal substrate was studied by SECM without adding a redox mediator. The system was mild steel coated by polyurethane in KCl. By selecting different values for the potential applied to the ultramicroelectrode tip, local concentrations of species involved in the degradation process are monitored, namely Fe(II) ions, hydrogen peroxide and oxygen. The results show a variation in both the shape and the magnitude of the scan lines measured over the holiday. A critical oxygen concentration was found below which the corrosion reaction is not observed.     

Validation of a Loop-Mediated Amplification/ISO 6579-Based Method for Analysing Soya Meal for the Presence of <Emphasis Type="Italic">Salmonella enterica</Emphasis>

An alternative method for detection of Salmonella spp. in animal feed, based on the use of loop-mediated amplification (LAMP) in conjunction with a standard culturing procedure, was compared with the standard ISO 6579 as reference method, using soya meal as the test matrix. In the method comparison study, the sensitivities for both the alternative and reference methods were 100 %. The relative level of detection was 1.000. Tested against 100 Salmonella and 30 non-Salmonella strains, the LAMP-based method was 99 % inclusive and 100 % exclusive. The interlaboratory trial involved ten laboratories from eight European countries, testing eight samples at three contamination levels: 0 cfu/100 g, 1–5 cfu/100 g and 14–68 cfu/100 g. The trial specificity, or percentage correct identification of uncontaminated samples, was 96.3 % for both the reference methods and the LAMP/ISO 6579 alternative method, thus demonstrating its suitability for adoption as a procedure for rapid identification of Salmonella uncontaminated soya meal.     

PSA Depletion Induces the Differentiation of Immature Neurons in the Piriform Cortex of Adult Mice

Immature neurons are maintained in cortical regions of the adult mammalian brain. In rodents, many of these immature neurons can be identified in the piriform cortex based on their high expression of early neuronal markers, such as doublecortin (DCX) and the polysialylated form of the neural cell adhesion molecule (PSA-NCAM). This molecule plays critical roles in different neurodevelopmental events. Taking advantage of a DCX-CreERT2/Flox-EGFP reporter mice, we investigated the impact of targeted PSA enzymatic depletion in the piriform cortex on the fate of immature neurons. We report here that the removal of PSA accelerated the final development of immature neurons. This was revealed by a higher frequency of NeuN expression, an increase in the number of cells carrying an axon initial segment (AIS), and an increase in the number of dendrites and dendritic spines on the immature neurons. Taken together, our results demonstrated the crucial role of the PSA moiety in the protracted development of immature neurons residing outside of the neurogenic niches. More studies will be required to understand the intrinsic and extrinsic factors affecting PSA-NCAM expression to understand how the brain regulates the incorporation of these immature neurons to the established neuronal circuits of the adult brain.     

The Alterations of Mitochondrial Function during NAFLD Progression—An Independent Effect of Mitochondrial ROS Production

The progression of non-alcoholic fatty liver (NAFL) into non-alcoholic steatohepatitis implicates multiple mechanisms, chief of which is mitochondrial dysfunction. However, the sequence of events underlying mitochondrial failure are still poorly clarified. In this work, male C57BL/6J mice were fed with a high-fat plus high-sucrose diet for 16, 20, 22, and 24 weeks to induce NAFL. Up to the 20th week, an early mitochondrial remodeling with increased OXPHOS subunits levels and higher mitochondrial respiration occurred. Interestingly, a progressive loss of mitochondrial respiration along “Western diet” feeding was identified, accompanied by higher susceptibility to mitochondrial permeability transition pore opening. Importantly, our findings prove that mitochondrial alterations and subsequent impairment are independent of an excessive mitochondrial reactive oxygen species (ROS) generation, which was found to be progressively diminished along with disease progression. Instead, increased peroxisomal abundance and peroxisomal fatty acid oxidation-related pathway suggest that peroxisomes may contribute to hepatic ROS generation and oxidative damage, which may accelerate hepatic injury and disease progression. We show here for the first time the sequential events of mitochondrial alterations involved in non-alcoholic fatty liver disease (NAFLD) progression and demonstrate that mitochondrial ROS are not one of the first hits that cause NAFLD progression.     

Exploring the functionality of starches from corms and cormels of Xanthosoma sagittifolium

Xanthosoma sagittifolium, belonging to the araceas family, represents an attractive alternative as a starch source. Nevertheless, as a rhizome plant two differentiated parts could be distinguished named corms and cormels." by "However, the rhizome of Xanthosoma sagittifolium has two differentiate parts named corms and cormels of Xanthosoma. Granules morphology, composition, hydration properties, pasting/thermal behaviour, as well as gelling performance were assessed. Scanning Electron Microscopy (SEM) revealed different morphology, granules were organised as aggregates in starch isolated from corms. Corms starch displayed lower hydration properties, lower apparent viscosity during heating and cooling and higher gelatinisation temperatures than cormels starch. Gels from corms starch showed less syneresis than cormels starch, but no significant differences were observed regarding their hardness. Therefore, the part of the araceas plant from which the starch is extracted must be always defined, because significant differences in their functionality are ascribed to their morphological origin.     

On the use of mercury-coated tips in scanning electrochemical microscopy to investigate galvanic corrosion processes involving zinc and iron

The corrosion processes related to zinc dissolution that take place in an iron–zinc galvanic pair exposed to a chloride solution were investigated by scanning electrochemical microscopy (SECM) using a mercury-coated platinum microelectrode as SECM tip. Both the release of zinc ions and the consumption of dissolved oxygen that occur in separate sites at the iron–zinc galvanic pair were monitored. Zinc ion quantification could be performed by stripping the zinc metal collected at the Hg-coated tip using linear sweep voltammetry.