Structural Evolution and Dynamics of an InO Catalyst for CO Hydrogenation to Methanol: An Operando XAS-XRD and In Situ TEM Study.

We report an operando examination of a model nanocrystalline InO catalyst for methanol synthesis via CO hydrogenation (300 °C, 20 bar) by combining X-ray absorption spectroscopy (XAS), X-ray powder diffraction (XRD), and in situ transmission electron microscopy (TEM). Three distinct catalytic regimes are identified during CO hydrogenation: activation, stable performance, and deactivation. The structural evolution of InO nanoparticles (NPs) with time on stream (TOS) followed by XANES-EXAFS-XRD associates the activation stage with a minor decrease of the In-O coordination number and a partial reduction of InO due to the formation of oxygen vacancy sites (i.

Mechanical stress impairs pheromone signaling via Pkc1-mediated regulation of the MAPK scaffold Ste5.

Cells continuously adapt cellular processes by integrating external and internal signals. In yeast, multiple stress signals regulate pheromone signaling to prevent mating under unfavorable conditions. However, the underlying crosstalk mechanisms remain poorly understood.

Normal stress difference-driven particle focusing in nanoparticle colloidal dispersion.

Colloidal dispersion has elastic properties due to Brownian relaxation process. However, experimental evidence for the elastic properties, characterized with normal stress differences, is elusive in shearing colloidal dispersion, particularly at low Péclet numbers ( < 1). Here, we report that single micrometer-sized polystyrene (PS) beads, suspended in silica nanoparticle dispersion (8 nm radius; 22%, v/v), laterally migrate and form a tightly focused stream by the normal stress differences, generated in pressure-driven microtube flow at low .

Design guidelines for an electron diffractometer for structural chemistry and structural biology.

3D electron diffraction has reached a stage where the structures of chemical compounds can be solved productively. Instrumentation is lagging behind this development, and to date dedicated electron diffractometers for data collection based on the rotation method do not exist. Current studies use transmission electron microscopes as a workaround.

Photoregulated fluxional fluorophores for live-cell super-resolution microscopy with no apparent photobleaching.

Photoswitchable molecules have multiple applications in the physical and life sciences because their properties can be modulated with light. Fluxional molecules, which undergo rapid degenerate rearrangements in the electronic ground state, also exhibit switching behavior. The stochastic nature of fluxional switching, however, has hampered its application in the development of functional molecules and materials.

Bidirectional Propagation of Signals and Nutrients in Fungal Networks via Specialized Hyphae.

Intercellular distribution of nutrients and coordination of responses to internal and external cues via endogenous signaling molecules are hallmarks of multicellular organisms. Vegetative mycelia of multicellular fungi are syncytial networks of interconnected hyphae resulting from hyphal tip growth, branching, and fusion. Such mycelia can reach considerable dimensions and, thus, different parts can be exposed to quite different environmental conditions.

Mechanisms of Tumor-Induced Lymphovascular Niche Formation in Draining Lymph Nodes.

Enlargement of the lymphatic vascular network in tumor-draining lymph nodes (LNs) often precedes LN metastasis, likely providing a lymphovascular niche for tumor cells. We investigated morphological and molecular changes associated with the lymphatic remodeling process, using the 4T1 breast cancer and B16F10 melanoma models. Lymphatic expansion in tumor-draining LNs is mediated by sprouting and proliferation of lymphatic endothelial cells (LECs) as early as 4 days after tumor implantation.

AutoTube: a novel software for the automated morphometric analysis of vascular networks in tissues.

Due to their involvement in many physiologic and pathologic processes, there is a great interest in identifying new molecular pathways that mediate the formation and function of blood and lymphatic vessels. Vascular research increasingly involves the image-based analysis and quantification of vessel networks in tissue whole-mounts or of tube-like structures formed by cultured endothelial cells in vitro. While both types of experiments deliver important mechanistic insights into (lymph)angiogenic processes, the manual analysis and quantification of such experiments are typically labour-intensive and affected by inter-experimenter variability.

Rapid Structure Determination of Microcrystalline Molecular Compounds Using Electron Diffraction.

Chemists of all fields currently publish about 50 000 crystal structures per year, the vast majority of which are X-ray structures. We determined two molecular structures by employing electron rather than X-ray diffraction. For this purpose, an EIGER hybrid pixel detector was fitted to a transmission electron microscope, yielding an electron diffractometer.

Three-dimensional scanning transmission electron microscopy of dislocation loops in tungsten.

Scanning transmission electron microscopy (STEM) imaging using diffraction contrast is a powerful technique to assess crystal defects. In this work it is used to assess the spatial distribution of radiation induced defect in tungsten. In effect, its irradiation leads to the formation of nanometric dislocation loops that under certain conditions may form intriguing 3-D rafts.

In Situ Atomic-Scale Observation of Surface-Tension-Induced Structural Transformation of Ag-NiP Core-Shell Nanocrystals.

The properties of nanocrystals are highly dependent on their morphology, composition, and structure. Tailored synthesis over these parameters is successfully applied for the production of nanocrystals with desired properties for specific applications. However, in order to obtain full control over the properties, the behavior of nanocrystals under external stimuli and application conditions needs to be understood.

Optimization of the structural characteristics of CaO and its effective stabilization yield high-capacity CO sorbents.

Calcium looping, a CO capture technique, may offer a mid-term if not near-term solution to mitigate climate change, triggered by the yet increasing anthropogenic CO emissions. A key requirement for the economic operation of calcium looping is the availability of highly effective CaO-based CO sorbents. Here we report a facile synthesis route that yields hollow, MgO-stabilized, CaO microspheres featuring highly porous multishelled morphologies.

OMNY-A tOMography Nano crYo stage.

For many scientific questions gaining three-dimensional insight into a specimen can provide valuable information. We here present an instrument called "tOMography Nano crYo (OMNY)," dedicated to high resolution 3D scanning x-ray microscopy at cryogenic conditions via hard X-ray ptychography. Ptychography is a lens-less imaging method requiring accurate sample positioning.

Robust workflow and instrumentation for cryo-focused ion beam milling of samples for electron cryotomography.

Electron cryotomography is able to visualize macromolecular complexes in their cellular context, in a frozen-hydrated state, and in three dimensions. The method, however, is limited to relatively thin samples. Cryo-focused ion beam (FIB) milling is emerging as a powerful technique for sample thinning prior to cryotomography imaging.

Apoptosis and eryptosis: Striking differences on biomembrane level.

The cell plasma membrane plays an essential role in programmed cell death of nucleated cells (apoptosis) and erythrocytes (eryptosis), and its changes due to loss of transmembrane asymmetry are quite similar. However, nucleated cells possess the network of intracellular membranes, which are missing in erythrocytes. Providing comparative studies with series of molecular probes, we observe dramatic differences in membrane lipid order in the course of apoptosis and eryptosis.

C-terminal calcium binding of α-synuclein modulates synaptic vesicle interaction.

Alpha-synuclein is known to bind to small unilamellar vesicles (SUVs) via its N terminus, which forms an amphipathic alpha-helix upon membrane interaction. Here we show that calcium binds to the C terminus of alpha-synuclein, therewith increasing its lipid-binding capacity. Using CEST-NMR, we reveal that alpha-synuclein interacts with isolated synaptic vesicles with two regions, the N terminus, already known from studies on SUVs, and additionally via its C terminus, which is regulated by the binding of calcium.

Microfluidic platform for single cell analysis under dynamic spatial and temporal stimulation.

Recent research on cellular responses is shifting from static observations recorded under static stimuli to real-time monitoring in a dynamic environment. Since cells sense and interact with their surrounding microenvironment, an experimental platform where dynamically changing cellular microenvironments should be recreated in vitro. There has been a lack of microfluidic devices to support spatial and temporal stimulations in a simple and robust manner.

Protein kinase C and calcineurin cooperatively mediate cell survival under compressive mechanical stress.

Cells experience compressive stress while growing in limited space or migrating through narrow constrictions. To survive such stress, cells reprogram their intracellular organization to acquire appropriate mechanical properties. However, the mechanosensors and downstream signaling networks mediating these changes remain largely unknown.

OMNY PIN-A versatile sample holder for tomographic measurements at room and cryogenic temperatures.

Nowadays ptychographic tomography in the hard x-ray regime, i.e., at energies above about 2 keV, is a well-established measurement technique.

A triaxial supramolecular weave.

Despite recent advances in the synthesis of increasingly complex topologies at the molecular level, nano- and microscopic weaves have remained difficult to achieve. Only a few diaxial molecular weaves exist-these were achieved by templation with metals. Here, we present an extended triaxial supramolecular weave that consists of self-assembled organic threads.

Architecture of crossed-lamellar bivalve shells: the southern giant clam (, Röding, 1798).

shells show a crossed lamellar microstructure consisting of three hierarchical lamellar structural orders. The mineral part is intimately intergrown with 0.9 wt% organics, namely polysaccharides, glycosylated and unglycosylated proteins and lipids, identified by Fourier transform infrared spectrometry.

A Photoactivatable Probe for Super-Resolution Imaging of Enzymatic Activity in Live Cells.

A dual-activatable, fluorogenic probe was developed to sense esterase activity with single-molecule resolution. Without enzymatic pre-activation, the diazoindanone-based probe has an electron-poor core and, upon irradiation, undergoes Wolff rearrangement to give a ring-expanded xanthene core that is nonemissive. If the probe is pre-activated by carboxylesterases, the tricyclic core becomes electron-rich, and the photoinduced Wolff rearrangement produces a highly emissive rhodol dye.

Dynamic surface self-reconstruction is the key of highly active perovskite nano-electrocatalysts for water splitting.

The growing need to store increasing amounts of renewable energy has recently triggered substantial R&D efforts towards efficient and stable water electrolysis technologies. The oxygen evolution reaction (OER) occurring at the electrolyser anode is central to the development of a clean, reliable and emission-free hydrogen economy. The development of robust and highly active anode materials for OER is therefore a great challenge and has been the main focus of research.

An environmental transfer hub for multimodal atom probe tomography.

Environmental control during transfer between instruments is required for samples sensitive to air or thermal exposure to prevent morphological or chemical changes prior to analysis. Atom probe tomography is a rapidly expanding technique for three-dimensional structural and chemical analysis, but commercial instruments remain limited to loading specimens under ambient conditions. In this study, we describe a multifunctional environmental transfer hub allowing controlled cryogenic or room-temperature transfer of specimens under atmospheric or vacuum pressure conditions between an atom probe and other instruments or reaction chambers.

VEGF-A Regulates Cellular Localization of SR-BI as Well as Transendothelial Transport of HDL but Not LDL.

Objective: Low- and high-density lipoproteins (LDL and HDL) must pass the endothelial layer to exert pro- and antiatherogenic activities, respectively, within the vascular wall. However, the rate-limiting factors that mediate transendothelial transport of lipoproteins are yet little known. Therefore, we performed a high-throughput screen with kinase drug inhibitors to identify modulators of transendothelial LDL and HDL transport.