Filamentous cable bacteria display unrivalled long-range electron transport, generating electrical currents over centimeter distances through a highly ordered network of fibers embedded in their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a biological material, but their chemical structure and underlying electron transport mechanism remain unresolved. Here, we combine high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate that the periplasmic wires consist of a conductive protein core surrounded by an insulating shell layer. The core proteins contain a sulfur-ligated nickel cofactor, and conductivity decreases when nickel is oxidized or selectively removed. The involvement of nickel as the active metal in biological conduction is remarkable, and suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures.

Filamentous cable bacteria display long-range electron transport, generating electrical currents over centimeter distances through a highly ordered network of fibers embedded in their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a biological material, but their chemical structure and underlying electron transport mechanism remain unresolved. Here, we combine high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate that the periplasmic wires consist of a conductive protein core surrounded by an insulating protein shell layer. The core proteins contain a sulfur-ligated nickel cofactor, and conductivity decreases when nickel is oxidized or selectively removed. The involvement of nickel as the active metal in biological conduction is remarkable, and suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures.

The introduction of adhesive bonding in the automotive industry is one of the key enabling technologies for the production of aluminium closures and all-aluminium car body structures. One of the main concerns limiting the use of adhesive joints is the durability of these system when exposed to service conditions. The present article primarily focuses on the different research works carried out for studying the effect of water, corrosive ions and external stresses on the performances of adhesively bonded joint structures. Water or moisture can affect the system by both modifying the adhesive properties or, more importantly, by causing failure at the substrate/adhesive interface. Ionic species can lead to the initiation and propagation of filiform corrosion and applied stresses can accelerate the detrimental effect of water or corrosion. Moreover, in this review the steps which the metal undergoes before being joined are described. It is shown how the metal preparation has an important role in the durability of the system, as it modifies the chemistry of the substrate’s top layer. In fact, from the adhesion theories discussed, it is seen how physical and chemical bonding, and in particular acid-base interactions, are fundamental in assuring a good substrate/adhesive adhesion.

Obtaining chemical information from the buried interface of an organic coating is not straightforward. In this paper, for the first time, atomic force microscopybased infrared spectroscopy (AFM-IR) is used to probe the chemical interactions at the metal oxide/polymer interface. AFM-IR is a novel technique that provides chemical spectra with spatial resolution below the optical diffraction limits. Poly(acrylic acid) (PAA) on aluminum oxide was chosen as a model system. Two different approaches were used: a thin-layer approach and a cross-section approach. The thin layer confirmed the validity of the AFM-IR to look at the buried interface by comparison with results from the literature. Additionally, with a line scan, the exposed interfaces obtained from cross sections of thick coatings on aluminum substrates were analyzed. A semiquantitative analysis of the spectra from the line scan allowed to identify the chemical contribution coming from the polymer/metal oxide interfaces.

De‐icing salts are commonly used on European roads during winter and are usually based on chlorides of sodium, magnesium, or calcium. The salt selection depends on the local climate and legislation. Therefore, the chemical composition of the de‐icing mixture can be very different within Europe. This represents an important challenge for the automotive industry as the corrosion behavior of automotive parts is intricately linked to the chemistry of the road environment. Furthermore, the use of aluminium alloys in the automotive industry increases due to a constant search for weight reduction. Till now, most of the corrosion studies on aluminium alloys in chloride based solutions have only been focused on sodium chloride. In this study, the effect of different chloride based salts on the corrosion of AA6016 was investigated. For that purpose, potentiodynamic polarization measurements were combined with surface analysis by SEM‐EDS and depth profiling using GDOES. Salts based on sodium and calcium showed similar effects on the corrosion behavior of AA6016 while the magnesium based salt reduced the corrosion rate. Mixture of sodium and magnesium based salts increased the corrosive attack.