Solid state electrochemistry and spectroelectrochemistry of poly(arylene bisimide–alt-oligoether)s

Two electroactive polymeric arylene bisimides, namely poly[(4,7,10-trioxatrideca-1,13-diyl)-(1,4,5,8-naphthalenetetracarboxylic bisimide-N,N′-diyl)] and its perylene analogue – poly[(4,7,10-trioxatrideca-1,13-diyl)-(3,4,9,10-perylenetetracarboxylic bisimide-N,N′-diyl)] have been synthesized and studied by cyclic voltammetry, UV–vis-NIR as well as Raman spectroeletrochemistry. Contrary to low molecular weight arylene bisimides, which show a clear two electron, double-step electrochemical reduction (neutral form to radical anion and from radical anion to dianion), in the synthesized polymers multielectron transfers are observed, accompanied with a strong electrochromic effect. However, as probed by cyclic voltammetry, their first reduction step is retarded and covers a wider potential range. We attribute this effect to macromolecular nature of the compounds being reduced and their structural inhomogeneity caused by π-stacking induced nanoaggregation of bisimide segments of the polymer chains. The second redox step seems unaffected by the polymeric nature of the electroactive compounds and yields a reduction peak similar to that registered for low molecular weight bisimides. Raman spectroelectrochemical data, combined with the established vibrational model of the perylene derivative – (poly[(4,7,10-trioxatrideca-1,13-diyl)-(3,4,9,10-perylenetetracarboxylic bisimide-N,N′-diyl)]) – enabled us to determine the mechanism of the first step of the electrochemical reduction process. The electrochemically induced shifts of the Raman bands unequivocally show that the reduction process results in the transformation of the carbonyl group into a radical anion. The surplus negative charge is delocalized on the six-member imide ring with the aromatic core very little affected.     

EVs from BALF—Mediators of Inflammation and Potential Biomarkers in Lung Diseases

Extracellular vesicles (EVs) have been identified as key messengers of intracellular communication in health and disease, including the lung. EVs that can be found in bronchoalveolar lavage fluid (BALF) are released by multiple cells of the airways including bronchial epithelial cells, endothelial cells, alveolar macrophages, and other immune cells, and they have been shown to mediate proinflammatory signals in many inflammatory lung diseases. They transfer complex molecular cargo, including proteins, cytokines, lipids, and nucleic acids such as microRNA, between structural cells such as pulmonary epithelial cells and innate immune cells such as alveolar macrophages, shaping mutually their functions and affecting the alveolar microenvironment homeostasis. Here, we discuss this distinct molecular cargo of BALF-EVs in the context of inducing and propagating inflammatory responses in particular acute and chronic lung disorders. We present different identified cellular interactions in the inflammatory lung via EVs and their role in lung pathogenesis. We also summarize the latest studies on the potential use of BALF-EVs as diagnostic and prognostic biomarkers of lung diseases, especially of lung cancer.     

The Role of Eph Receptors and Ephrins in Corneal Physiology and Diseases

The cornea, while appearing to be simple tissue, is actually an extremely complex structure. In order for it to retain its biomechanical and optical properties, perfect organization of its cells is essential. Proper regeneration is especially important after injuries and in the course of various diseases. Eph receptors and ephrin are mainly responsible for the proper organization of tissues as well as cell migration and communication. In this review, we present the current state of knowledge on the role of Eph and ephrins in corneal physiology and diseases, in particular, we focused on the functions of the epithelium and endothelium. Since the role of Eph and ephrins in the angiogenesis process has been well established, we also analyzed their influence on conditions with corneal neovascularization.     

The G-Protein-Coupled Membrane Estrogen Receptor Is Present in Horse Cryptorchid Testes and Mediates Downstream Pathways

Cryptorchidism in horses is a commonly occurring malformation. The molecular basis of this pathology is not fully known. In addition, the origins of high intratesticular estrogen levels in horses remain obscure. In order to investigate the role of the G-protein-coupled membrane estrogen receptor (GPER) and establish histological and biochemical cryptorchid testis status, healthy and cryptorchid horse testes were subjected to scanning electron microscopy analysis, histochemical staining for total protein (with naphthol blue black; NBB), acid content (with toluidine blue O; TBO), and polysaccharide content (with periodic acid–Schiff; PAS). The expression of GPER was analyzed by immunohistochemistry and Western blot. GPER-mediated intracellular cAMP and calcium (Ca2+) signaling were measured immunoenzymatically or colorimetrically. Our data revealed changes in the distribution of polysaccharide content but not the protein and acid content in the cryptorchid testis. Polysaccharides seemed to be partially translocated from the interstitial compartment to the seminiferous tubule compartment. Moreover, the markedly decreased expression of GPER and GPER downstream molecules, cAMP and Ca2+, suggests their potential role in testis pathology. Increased estrogen levels in cryptorchid conditions may be linked to disturbed GPER signaling. We postulate that GPER is a prominent key player in testis development and function and may be used as a new biomarker of horse testis in health and disease.     

Innovationen durch PACVD Duplex Schichtsysteme im Leichtmetall‐Druckguss

Innovative PACVD Duplex Layer Systems applied for the Light Metal Die Casting Process Duplex‐PACVD hard coatings are well‐known for increasing the tool performance in terms of adhesion, wear, fatigue, and corrosion resistance of the steel. The developments made in synthesizing duplex nanostructure and nanocomposite, mono and gradient layers based on borides are described. The aim of the investigation is to optimize the surface capability by plasma process combinations: duplex process, gradient‐layer. Within this work different types of duplex hard coatings produced by PACVD were investigated in terms of their tribological behavior and were tested in aluminum and magnesium die casting applications. Practical tests have been carried out by automobile producers and part suppliers. All coatings tested on die casting tools showed a significant increase of lifetime and a reduced metal adhesion tendency. The economic efficiency of coated die casting tools could be proved.     

Near-infrared probe for in situ characterization of nafion thin films

A near-infrared (NIR)-absorbing cyanine dye was used as a probe for in situ characterization of Nafion thin films. This NIR dye was very sensitive to changes in the hydrophobicity of the environment and proved to be very suitable for probing the Nafion coatings, which involve a two-Phase structure of hydrophobic and hydrophilic zones. Sorption phenomena of water and aqueous alkali salt solutions by Nafion were investigated. For our study systems of thin-coating films prepared from 5% wt alcoholic solution of Nafion 117, the absorption spectrum was dominated by higher-order aggregates when in dry form. In pure water, the absorption maximum of the monomer dye appears at 773 nm and can be used as an indication of the swelling process of the film. The water uptake reaches saturation in only a few seconds. After the swelling process, an additional absorption band with a maximum at 555 nm appears primarily at the expense of the NIR monomer dye absorption band. The peak transition process, which is a very slow process and is a strong function of the water content inside the matrix, can be used as an indication of the establishment of equilibrium between the two-phase structure due to the water uptake. Since the absorption maximum of the study system is around 800 nm, semiconductor lasers can be used. This technique shows high potential in other applications where polymers are used as support material, e.g., in situ thin-film thickness measurements. In the study, the feasibility of this approach was illustrated.     

Mixing fuel particles for space combustion research using acoustics

Part of the microgravity science to be conducted aboard the Shuttle (STS) involves combustion using solids, particles, and liquid droplets. The central experimental facts needed for characterization of premixed quiescent particle cloud flames cannot be adequately established by normal gravity studies alone. This paper describes the experimental results to date of acoustically mixing a prototypical particulate, lycopodium, in a 5 cm diameter by 75 cm long flame tube aboard a Learjet aircraft flying a 20-sec low-gravity trajectory. Photographic and light detector instrumentation combine to measure and characterize particle cloud uniformity. This paper is based on a presentation made in the symposium “Experimental Methods for Microgravity Materials Science Research” presented at the 1988 TMS-AIME Annual Meeting in Phoenix, Arizona, January 25-29, 1988, under the auspices of the ASM/MSD Thermo-dynamic Data Committee and the Material Processing Committee.