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Background Although plastic pollution is increasing worldwide, very little is known about the microbial processes that take place once plastic debris is incorporated into the soil matrix. In this study, we conducted the first metatranscriptome analysis of polyethylene (PE)-associated biofilm communities in highly polluted landfill soil and compared their gene expression to that of a forest soil community within a 53-day period. Results Our findings indicate that the microbial population present in soil contaminated with plastic debris is predisposed to both inhabit and degrade plastic surfaces. Surprisingly, the microbial community from undisturbed forest soil contained a diverse array of plastic-associated genes ( PETase , alkB , etc.), indicating the presence of an enzymatic machinery capable of plastic degradation. Plastic-degrading taxa were upregulated in the early stages of biofilm formation. During the maturation of the biofilm, the alkB1/alkM transcripts, which encode PE-degrading enzymes, and transporters such as fadL, livG, livF, livH, and livM were upregulated, along with transcripts associated with the fatty acid β-oxidation pathway. Conclusions In this study, we address the underlying patterns of gene expression during biofilm development in a PE-associated plastisphere in soil and address the pressing question of whether natural microbial communities have the potential to biodegrade petrochemical-based plastic in the soil environment.

Liquid‐Phase Transmission Electron Microscopy (LP‐TEM) enables in situ observations of the dynamic behavior of materials in liquids at high spatial and temporal resolution. During LP‐TEM, incident electrons decompose water molecules into highly reactive species. Consequently, the chemistry of the irradiated aqueous solution is strongly altered, impacting the reactions to be observed. However, the short lifetime of these reactive species prevent their direct study. Here, the morphological changes of goethite during its dissolution are used as a marker system to evaluate the influence of radiation on the changes in solution chemistry. At low electron flux density, the morphological changes are equivalent to those observed under bulk acidic conditions, but the rate of dissolution is higher. On the contrary, at higher electron fluxes, the morphological evolution does not correspond to a unique acidic dissolution process. Combined with kinetic simulations of the steady state concentrations of generated reactive species in the aqueous medium, the results provide a unique insight into the redox and acidity interplay during radiation induced chemical changes in LP‐TEM. The results not only reveal beam‐induced radiation chemistry via a nanoparticle indicator, but also open up new perspectives in the study of the dissolution process in industrial or natural settings. In situ Liquid‐Phase Transmission Electron Microscopy observations of the morphological changes of goethite nanoparticles during its dissolution are used to evaluate the influence of radiation on changes in solution chemistry. The results not only reveal beam‐induced radiation chemistry via a nanoparticulate indicator, but also open up new perspectives in the study of dissolution processes in industrial and natural settings.

With comprehensive crystal growth experiments of β‐(AlxGa1‐x)2O3 by the Czochralski method this work concludes a maximum [Al] = 40 mol% (35 mol% in the melt) that can be incorporated into β‐Ga2O3 crystal lattice while keeping single crystalline and monoclinic phase, resulting in the formula of β‐(Al0.4Ga0.6)2O3. Transmission Electron Microscopy (TEM) analysis reveals random distribution of Al across both octahedral and tetrahedral sites. This work has shown, that incorporation of only [Ga] ≥ 5 mol% into α‐Al2O3 crystals leads to a phase separation of (α + θ)‐Al2O3. With electrical measurements this work proves an increase of the electrical resistivity of β‐(AlxGa1‐x)2O3:Mg as compared to β‐Ga2O3:Mg. The static dielectric constant and refractive index both decrease with [Al]. Raman spectra shows a continuous shift and broadening of the peaks, with the low energy optical phonons Ag(3) having a large contribution to a decrease in the electron mobility. Further, Ir incorporation into the crystals decreases with [Al], wherein Ir4+ Raman peak disappears already at [Al] ≥ 15 mol%. Finally, thermal conductivity measurements on β‐(AlxGa1‐x)2O3 crystals show a drastic decrease of its values with [Al], to about 1/3 of the β‐Ga2O3 value at [Al] = 30 mol%. Bulk β‐(AlxGa1‐x)2O3 crystals are grown by the Czochralski method, with a maximum [Al] = 40 mol% that can be incorporated into β‐Ga2O3 crystal lattice while keeping single crystalline and monoclinic phase. From obtained crystals physical properties (optical, electrical, thermal) are revealed as a function of [Al]. Also, even small Ga incorporation into α‐Al2O3 crystals leads to a phase separation.

Meteorites contain a record of their thermal and magnetic history, written in the intergrowths of iron-rich and nickel-rich phases that formed during slow cooling. Of intense interest from a magnetic perspective is the “cloudy zone,” a nanoscale intergrowth containing tetrataenite—a naturally occurring hard ferromagnetic mineral that has potential applications as a sustainable alternative to rare-earth permanent magnets. Here we use a combination of high-resolution electron diffraction, electron tomography, atom probe tomography (APT), and micromagnetic simulations to reveal the 3D architecture of the cloudy zone with subnanometer spatial resolution and model the mechanism of remanence acquisition during slow cooling on the meteorite parent body. Isolated islands of tetrataenite are embedded in a matrix of an ordered superstructure. The islands are arranged in clusters of three crystallographic variants, which control how magnetic information is encoded into the nanostructure. The cloudy zone acquires paleomagnetic remanence via a sequence of magnetic domain state transformations (vortex to two domain to single domain), driven by Fe–Ni ordering at 320 °C. Rather than remanence being recorded at different times at different positions throughout the cloudy zone, each subregion of the cloudy zone records a coherent snapshot of the magnetic field that was present at 320 °C. Only the coarse and intermediate regions of the cloudy zone are found to be suitable for paleomagnetic applications. The fine regions, on the other hand, have properties similar to those of rare-earth permanent magnets, providing potential routes to synthetic tetrataenite-based magnetic materials.

Advanced in situ techniques based on electrons and X-rays are increasingly used to gain insights into fundamental materials dynamics in liquid media. Yet, ionizing radiation changes the solution chemistry. In this work, we show that ionizing radiation decouples the acidity from autoprotolysis. Consequently, pH is insufficient to capture the acidity of water-based systems under irradiation. Via radiolysis simulations, we provide a more conclusive description of the acid-base interplay. Finally, we demonstrate that acidity can be tailored by adjusting the dose rate and adding pH-irrelevant species. This opens up a huge parameter landscape for studies involving ionizing radiation.

Czochralski Method High‐angle annular dark‐field scanning transmission electron microscopy image of a β‐(Al0.2Ga0.8)2O3 crystal along the [010] projection grown by the Czochralski method. More details can be found in article 2400122 by Zbigniew Galazka and co‐workers.