Magnetochrome-catalyzed oxidation of ferrous iron by MamP enables magnetite crystal growth in the magnetotactic bacterium AMB-1.

Magnetotactic bacteria have evolved the remarkable capacity to biomineralize chains of magnetite [Fe(II)Fe(III)O] nanoparticles that align along the geomagnetic field and optimize their navigation in the environment. Mechanisms enabling magnetite formation require the complex action of numerous proteins for iron acquisition, sequestration in dedicated magnetosome organelles, and precipitation into magnetite. The MamP protein contains c-type cytochromes called magnetochrome domains that are found exclusively in magnetotactic bacteria.

Hard carbon from a sugar derivative for next-generation sodium-ion batteries.

Sodium-ion batteries have emerged as a promising secondary battery system due to the abundance of sodium resources. One of the boosters for accelerating the practical application of sodium-ion batteries is the innovation in anode materials. This study focuses on developing a high-performance hard carbon anode material derived from hydroxymethylfurfural, produced from carbohydrates, using a straightforward thermal condensation method.

Bone strength and residual compressive stress in apatite crystals.

Residual stresses are omnipresent in composite materials, often arising during the fabrication process. Residual compressive stresses were recently observed to develop in collagen fibrils during the process of mineralization. They have in fact been reported in a range of bony materials spanning tooth dentin to mammalian and fish bones.

Enhancing deep visible-light photoelectrocatalysis with a single solid-state synthesis: Carbon nitride/TiO heterointerface.

Visible-light responsive, stable, and abundant absorbers are required for the rapid integration of green, clean, and renewable technologies in a circular economy. Photoactive solid-solid heterojunctions enable multiple charge pathways, inhibiting recombination through efficient charge transfer across the interface. This study spotlights the physico-chemical synergy between titanium dioxide (TiO) anatase and carbon nitride (CN) to form a hybrid material.

Solvent Cavitation during Ambient Pressure Drying of Silica Aerogels.

Ambient-pressure drying of silica gels stands out as an economical and accessible process for producing monolithic silica aerogels. Gels experience significant deformations during drying due to the capillary pressure generated at the liquid-vapor interface in submicron pores. Proper control of the gel properties and the drying rate is essential to enable reversible drying shrinkage without mechanical failure.

Microporous Sulfur-Carbon Materials with Extended Sodium Storage Window.

Developing high-performance carbonaceous anode materials for sodium-ion batteries (SIBs) is still a grand quest for a more sustainable future of energy storage. Introducing sulfur within a carbon framework is one of the most promising attempts toward the development of highly efficient anode materials. Herein, a microporous sulfur-rich carbon anode obtained from a liquid sulfur-containing oligomer is introduced.

Springback effect of ambient-pressure-dried silica aerogels: nanoscopic effects of silylation revealed by synchrotron X-ray scattering.

Ambient pressure drying (APD) allows for synthesizing aerogels without expensive and sophisticated equipment for achieving supercritical conditions. Since APD does not eliminate the capillary stress that is induced by the liquid/vapour phase boundary, the shrinkage during drying needs to be prevented or reversed. The re-expansion of the silylated silica gels during drying is commonly referred to as the springback effect (SBE).

Invasive mussels fashion silk-like byssus via mechanical processing of massive horizontally acquired coiled coils.

Zebra and quagga mussels () are invasive freshwater biofoulers that perpetrate devastating economic and ecological impact. Their success depends on their ability to anchor onto substrates with protein-based fibers known as byssal threads. Yet, compared to other mussel lineages, little is understood about the proteins comprising their fibers or their evolutionary history.

Evidence for liquid-liquid phase separation during the early stages of Mg-struvite formation.

The precipitation of struvite, a magnesium ammonium phosphate hexahydrate (MgNH4PO4 · 6H2O) mineral, from wastewater is a promising method for recovering phosphorous. While this process is commonly used in engineered environments, our understanding of the underlying mechanisms responsible for the formation of struvite crystals remains limited. Specifically, indirect evidence suggests the involvement of an amorphous precursor and the occurrence of multi-step processes in struvite formation, which would indicate non-classical paths of nucleation and crystallization.

Origin of the Springback Effect in Ambient-Pressure-Dried Silica Aerogels: The Effect of Surface Silylation.

Ambient pressure drying (APD) can prospectively reduce the costs of aerogel fabrication and processing. APD relies solely on preventing shrinkage or making it reversible. The latter, i.

The complex structure of represents an architectural design for high-performance ultralightweight materials.

High strength, hardness, and fracture toughness are mechanical properties that are not commonly associated with the fleshy body of a fungus. Here, we show with detailed structural, chemical, and mechanical characterization that is an exception, and its architectural design is a source of inspiration for an emerging class of ultralightweight high-performance materials. Our findings reveal that .

Crystal-Chemical and Biological Controls of Elemental Incorporation into Magnetite Nanocrystals.

Magnetite nanoparticles possess numerous fundamental, biomedical, and industrial applications, many of which depend on tuning the magnetic properties. This is often achieved by the incorporation of trace and minor elements into the magnetite lattice. Such incorporation was shown to depend strongly on the magnetite formation pathway (i.

Primary radiation damage in bone evolves via collagen destruction by photoelectrons and secondary emission self-absorption.

X-rays are invaluable for imaging and sterilization of bones, yet the resulting ionization and primary radiation damage mechanisms are poorly understood. Here we monitor in-situ collagen backbone degradation in dry bones using second-harmonic-generation and X-ray diffraction. Collagen breaks down by cascades of photon-electron excitations, enhanced by the presence of mineral nanoparticles.

Gradients of Orientation, Composition, and Hydration of Proteins for Efficient Light Collection by the Cornea of the Horseshoe Crab.

The lateral eyes of the horseshoe crab, Limulus polyphemus, are the largest compound eyes within recent Arthropoda. The cornea of these eyes contains hundreds of inward projecting elongated cuticular cones and concentrate light onto proximal photoreceptor cells. Although this visual system has been extensively studied before, the precise mechanism allowing vision has remained controversial.

Characterization of lipid bilayers adsorbed to functionalized air/water interfaces.

Lipid bilayers immobilized in planar geometries, such as solid-supported or "floating" bilayers, have enabled detailed studies of biological membranes with numerous experimental techniques, notably X-ray and neutron reflectometry. However, the presence of a solid support also has disadvantages as it complicates the use of spectroscopic techniques as well as surface rheological measurements that would require surface deformations. Here, in order to overcome these limitations, we investigate lipid bilayers adsorbed to inherently soft and experimentally well accessible air/water interfaces that are functionalized with Langmuir monolayers of amphiphiles.

Cellulose lattice strains and stress transfer in native and delignified wood.

Small specimens of spruce wood with different degrees of delignification were studied using in-situ tensile tests and simultaneous synchrotron X-ray diffraction to reveal the effect of delignification and densification on their tensile properties at relative humidities of 70-80 %. In addition to mechanical properties, these analyses yield the ratio of strains in the cellulose crystals and in the bulk, which reflects the stress-transfer to crystalline cellulose. While the specific modulus of elasticity slightly increases from native wood by partial or complete delignification, the lattice strain ratio does not show a significant change.

Order vs. Disorder: Cholesterol and Omega-3 Phospholipids Determine Biomembrane Organization.

Lipid structural diversity strongly affects biomembrane chemico-physical and structural properties in addition to membrane-associated events. At high concentrations, cholesterol increases membrane order and rigidity, while polyunsaturated lipids are reported to increase disorder and flexibility. How these different tendencies balance in composite bilayers is still controversial.

Springback effect and structural features during the drying of silica aerogels tracked by in-situ synchrotron X-ray scattering.

The springback effect during ambient pressure drying of aerogels is an interesting structural phenomenon, consisting of a severe shrinkage followed by almost complete re-expansion. The drying of gels causes shrinkage, whereas re-expansion is believed to be linked to repelling forces on the nanoscale. A multi-scale structural characterization of this significant volume change is key in controlling aerogel processing and properties.

Mineralization generates megapascal contractile stresses in collagen fibrils.

During bone formation, collagen fibrils mineralize with carbonated hydroxyapatite, leading to a hybrid material with excellent properties. Other minerals are also known to nucleate within collagen in vitro. For a series of strontium- and calcium-based minerals, we observed that their precipitation leads to a contraction of collagen fibrils, reaching stresses as large as several megapascals.

Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate.

A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO ] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium.

Multiscale X-ray study of biofilms reveals interlinked structural hierarchy and elemental heterogeneity.

Biofilms are multicellular microbial communities that encase themselves in an extracellular matrix (ECM) of secreted biopolymers and attach to surfaces and interfaces. Bacterial biofilms are detrimental in hospital and industrial settings, but they can be beneficial, for example, in agricultural as well as in food technology contexts. An essential property of biofilms that grants them with increased survival relative to planktonic cells is phenotypic heterogeneity, the division of the biofilm population into functionally distinct subgroups of cells.

Seeds of imperfection rule the mesocrystalline disorder in natural anhydrite single crystals.

In recent years, we have come to appreciate the astounding intricacies associated with the formation of minerals from ions in aqueous solutions. In this context, a number of studies have revealed that the nucleation of calcium sulfate systems occurs nonclassically, involving the aggregation and reorganization of nanosized prenucleation species. In recent work, we have shown that this particle-mediated nucleation pathway is actually imprinted in the resultant micrometer-sized CaSO crystals.

Investigating the Conformation of Surface-Adsorbed Proteins with Standing-Wave X-ray Fluorescence.

Protein adsorption to surfaces is at the heart of numerous technological and bioanalytical applications, but sometimes, it is also associated with medical risks. To deepen our insights into processes involving layers of surface-adsorbed proteins, high-resolution structural information is essential. Here, we use standing-wave X-ray fluorescence (SWXF) in combination with an optimized liquid-cell setup to investigate the underwater conformation of the random-coiled phosphoprotein β-casein adsorbed to hydrophilic and hydrophobized solid surfaces.

Not just a fluidifying effect: omega-3 phospholipids induce formation of non-lamellar structures in biomembranes.

Polyunsaturated omega-3 fatty acid docosahexaenoic acid (DHA) is found in very high concentrations in a few peculiar tissues, suggesting that it must have a specialized role. DHA was proposed to affect the function of the cell membrane and related proteins through an indirect mechanism of action, based on the DHA-phospholipid effects on the lipid bilayer structure. In this respect, most studies have focused on its influence on lipid-rafts, somehow neglecting the analysis of effects on liquid disordered phases that constitute most of the cell membranes, by reporting in these cases only a general fluidifying effect.

Reflectometry Reveals Accumulation of Surfactant Impurities at Bare Oil/Water Interfaces.

Bare interfaces between water and hydrophobic media like air or oil are of fundamental scientific interest and of great relevance for numerous applications. A number of observations involving water/hydrophobic interfaces have, however, eluded a consensus mechanistic interpretation so far. Recent theoretical studies ascribe these phenomena to an interfacial accumulation of charged surfactant impurities in water.