Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part II: Effect on biofilm formation and microbially influenced corrosion processes

Biofilm formation and microbially influenced corrosion of the iron-reducing microorganism Shewanella putrefaciens were investigated on stainless steel surfaces preconditioned in the absence and presence of flavin molecules by means of XANES (X-ray absorption near-edge structure) analysis and electrochemical methods. The results indicate that biofilm formation was promoted on samples preconditioned in electrolytes containing minute amounts of flavins. On the basis of the XANES results, the corrosion processes are controlled by the iron-rich outer layer of the passive film. Biofilm formation resulted in a cathodic shift of the open circuit potential and a protective effect in terms of pitting corrosion. The samples preconditioned in the absence of flavins have shown delayed pitting and the samples preconditioned in the presence of flavins did not show any pitting in a window of −0.3- to +0.0-V overpotential in the bacterial medium. The results indicate that changes in the passive film chemistry induced by the presence of minute amounts of flavins during a mild anodic polarization can change the susceptibility of stainless steel surfaces to microbially influenced corrosion.     

(Metal yolk)/(porous ceria shell) nanostructures for high-performance plasmonic photocatalysis under visible light

We describe a route to the preparation of (metal yolk)/(porous ceria shell) nanostructures through the heterogeneous growth of ceria on porous metal nanoparticles followed by the calcination-induced shrinkage of the nanoparticles. The approach allows for the control of the ceria shell thickness, the metal yolk composition and size, which is difficult to realize through common templating approaches. The yolk/shell nanostructures with monometallic Pt and bimetallic PtAg yolks featuring plasmon-induced broadband light absorption in the visible region are rationally designed and constructed. The superior photocatalytic activities of the obtained nanostructures are demonstrated by the selective oxidation of benzyl alcohol under visible light. The excellent activities are ascribed to the synergistic effects of the metal yolk and the ceria shell on the light absorption, electron-hole separation and efficient mass transfer. Our synthesis of the (metal yolk)/(porous ceria shell) nanostructures points out a way to the creation of sophisticated heteronanostructures for high-performance photocatalysis.

     

Lipids and Antiplatelet Therapy: Important Considerations and Future Perspectives

Lipids play an essential role in platelet functions. It is known that polyunsaturated fatty acids play a role in increasing platelet reactivity and that the prothrombotic phenotype plays a crucial role in the occurrence of major adverse cardiovascular events. The ongoing increase in cardiovascular diseases’ incidence emphasizes the importance of research linking lipids and platelet function. In particular, the rebound phenomenon that accompanies discontinuation of clopidogrel in patients receiving dual antiplatelet therapy has been associated with changes in the lipid profile. Our many years of research underline the importance of reduced HDL values for the risk of such a rebound effect and the occurrence of thromboembolic events. Lipids are otherwise a heterogeneous group of molecules, and their signaling molecules are not deposited but formed “on-demand” in the cell. On the other hand, exosomes transmit lipid signals between cells, and the profile of such changes can be monitored by lipidomics. Changes in the lipid profile are organ-specific and may indicate new drug action targets.     

Stationary and Progressive Phenotypes Caused by the p.G90D Mutation in Rhodopsin Gene

Mutations in rhodopsin gene (RHO) are a frequent cause of retinitis pigmentosa (RP) and less often, congenital stationary night blindness (CSNB). Mutation p.G90D has previously been associated with CSNB based on the examination of one family. This study screened 60 patients. Out of these 60 patients, 32 were affected and a full characterization was conducted in 15 patients. We described the clinical characteristics of these 15 patients (12 male, median age 42 years, range 8–71) from three families including visual field (Campus Goldmann), fundus autofluorescence (FAF), optical coherence tomography (OCT) and electrophysiology. Phenotypes were classified into four categories: CSNB (N = 3, 20%) sector RP (N = 3, 20%), pericentral RP (N = 1, 6.7%) and classic RP (N = 8, 53.3% (8/15)). The phenotypes were not associated with family, sex or age (Kruskal–Wallis, p > 0.05), however, cystoid macular edema (CME) was observed only in one family. Among the subjects reporting nyctalopia, 69% (22/32) were male. The clinical characteristics of the largest p.G90D cohort so far showed a large frequency of progressive retinal degeneration with 53.3% developing RP, contrary to the previous report.     

Correction to: Digitalization in knowledge work: the dream of enhanced performance

According to decision by the rector of University of Tampere, a version of the paper was submitted and published due to negligence.     

Can’t bibliometric analysts do better? How quality assessment without field expertise does not work

Scientometrics - The article is an invited comment on Guy Madison and Therese Söderlund (M&S): Comparisons of content and scientific quality indicators across peer-reviewed journal...     

Bi3+ as an enhancer for down- and upconversion luminescence in ternary vanadate structures

A series of dual-mode nanomaterials based on Ba₂LaV₃O₁₁:Yb³⁺, Er³⁺, Bi³⁺, with different bismuth content were synthesized using the hydrothermal method. Various analytical methods, such as x-ray diffraction (XRD) with additional detailed Rietveld analysis, transmission electron microscopy (TEM), inductively coupled plasma mass spectroscopy (ICP-MS) and laser spectroscopy have confirmed that with increasing Bi³⁺ content, phase purity, optical absorption and luminescence intensity significantly increased. Moreover, a slight luminescence color tunability was observed along with the gradual introduction of bismuth into the host structure since, among the others, the local crystal field around emitting Er³⁺ ions was changing. The use of ultraviolet and near-infrared excitation wavelengths allowed to obtain a dual mode luminescence, which extended the emission range and demonstrated the possibility of using the studied materials, e.g. in solar cells.     

Influence of Macromolecular Brushes with Polyimide Backbones and Poly(methyl methacrylate) Side Chains on Structure,Physical, and Transport Properties of Polyphthalamide

Composite films based on polyamide (poly(m-phenylene-iso-phthalamide)) (PA) and a brush-like polymer with polyimide (PI) backbone and side poly(methyl methacrylate) chains (PI-PMMA) were prepared by mixing individual solutions of PA and PI-PMMA and subsequent film casting. Macromolecular brushes with the same backbone length and density of side chains but with various lengths of side PMMA chains were synthesized via activator generated by electron transfer atom transfer radical polymerization. Interactions between PA and PI-PMMA, as well as distribution of PI-PMMA filler inside the PA matrix, were studied by viscometry, dynamic light scattering, differential scanning calorimetry, scanning electron microscopy, and IR spectroscopy. The mechanical properties of polymer samples were also investigated. Microphase separation was revealed in PA/PI-PMMA films. The length of side chains influences interactions between PA and PI-PMMA. At the same time, the degree of reduction in the rigidity parameters and in the elasticity parameter depends on the side chain length. Diffusion membranes were prepared on the basis of compositions with the best mechanical properties; these membranes proved to be highly efficient in pervaporation of methanol–hexane mixture. It was established that the fluxes and separation factors of the studied membranes are several times higher as compared to the corresponding characteristics of known commercial membranes. POLYM. ENG. SCI., 60:481–490, 2020. © 2019 Society of Plastics Engineers