375 results match your criteria: "Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons[Affiliation]"

Microfluidic investigation of pore-size dependency of barite nucleation.

Commun Chem

November 2023

Laboratory for Waste Management, Paul Scherrer Institut, CH-5232, Villigen PSI, Switzerland.

The understanding and prediction of mineral precipitation processes in porous media are relevant for various energy-related subsurface applications. While it is well known that thermodynamic effects can inhibit crystallization in pores with sizes <0.1 µm, the retarded observation of mineral precipitation as function of pore size is less explored.

View Article and Find Full Text PDF

Polymorphism (and its extended form - pseudopolymorphism) in solids is ubiquitous in mineralogy, crystallography, chemistry/biochemistry, materials science, and the pharmaceutical industries. Despite the difficulty of controlling (pseudo-)polymorphism, the realization of specific (pseudo-)polymorphic phases and associated boundary structures is an efficient route to enhance material performance for energy conversion and electromechanical applications. Here, this work applies the pseudopolymorphic phase (PP) concept to a thermoelectric copper sulfide, Cu S (x ≤ 0.

View Article and Find Full Text PDF
Article Synopsis
  • Researchers created ultrasmall silver-platinum nanoparticles (Ag:Pt ratio of 50:50) and compared them to pure silver, platinum, and gold nanoparticles, all measuring 2 nm in diameter, stabilized with a glutathione (GSH) layer.* -
  • Various characterization techniques (HRTEM, ED, XRD, SAXS, DCS, UV spectroscopy, and NMR) established the size and composition of the nanoparticles, revealing around 200 GSH ligands per particle and different binding positions on gold nanoparticle surfaces.* -
  • Analysis showed that the alloyed silver-platinum nanoparticles were mostly amorphous, unlike the crystalline nature of pure platinum and gold, and indicated partial oxidation in silver
View Article and Find Full Text PDF

When using the unit cell average of first moment data from four-dimensional scanning transmission electron microscopy (4D-STEM) to characterize ferroelectric materials, a variety of sources of systematic errors needs to be taken into account. In particular, these are the magnitude of the acceleration voltage, STEM probe semi-convergence angle, sample thickness, and sample tilt out of zone axis. Simulations show that a systematic error of calculated electric fields using the unit cell averaged momentum transfer originates from violation of point symmetry within the unit cells.

View Article and Find Full Text PDF

We propose a modification of Wigner distribution deconvolution (WDD) to support live processing ptychography. Live processing allows to reconstruct and display the specimen transmission function gradually while diffraction patterns are acquired. For this purpose, we reformulate WDD and apply a dimensionality reduction technique that reduces memory consumption and increases processing speed.

View Article and Find Full Text PDF

This work investigates the effect of copper substitution on the magnetic properties of SmCo thin films synthesized by molecular beam epitaxy. A series of thin films with varying concentrations of Cu were grown under otherwise identical conditions to disentangle structural and compositional effects on the magnetic behavior. The combined experimental and theoretical studies show that Cu substitution at the Co sites not only stabilizes the formation of the SmCo structure but also enhances magnetic anisotropy and coercivity.

View Article and Find Full Text PDF

Conserved structures of ESCRT-III superfamily members across domains of life.

Trends Biochem Sci

November 2023

Department of Chemistry, Biochemistry, Johannes Gutenberg University Mainz, Germany; Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Mainz, Germany. Electronic address:

Structural and evolutionary studies of cyanobacterial phage shock protein A (PspA) and inner membrane-associated protein of 30 kDa (IM30) have revealed that these proteins belong to the endosomal sorting complex required for transport-III (ESCRT-III) superfamily, which is conserved across all three domains of life. PspA and IM30 share secondary and tertiary structures with eukaryotic ESCRT-III proteins, whilst also oligomerizing via conserved interactions. Here, we examine the structures of bacterial ESCRT-III-like proteins and compare the monomeric and oligomerized forms with their eukaryotic counterparts.

View Article and Find Full Text PDF
Article Synopsis
  • - The novel Fe-Pt-YbO core-shell nanoparticles, measuring 10 nm, can effectively diffuse through neuronal tissue and can be controlled with magnetic fields for enhanced biomedical applications, including cancer treatment.
  • - These nanoparticles exhibit superparamagnetic properties initially and become ferromagnetic after annealing, which improves NMRI contrast and allows for hyperthermia treatment purposes.
  • - Neutron-activation of the shell leads to the incorporation of low-energy β-radiation isotopes (Yb, Lu) that, combined with their capability for optical visualization, successfully killed over 98% of human glioblastoma cells in tests, showcasing their potential in cancer therapies.
View Article and Find Full Text PDF

Dirac materials are characterized by the emergence of massless quasiparticles in their low-energy excitation spectrum that obey the Dirac Hamiltonian. Known examples of Dirac materials are topological insulators, d-wave superconductors, graphene, and Weyl and Dirac semimetals, representing a striking range of fundamental properties with potential disruptive applications. However, none of the Dirac materials identified so far shows metallic character.

View Article and Find Full Text PDF

The bactericidal effects of silver nanoparticles (Ag NPs) against infectious strains of multiresistant bacteria is a well-studied phenomenon, highly relevant for many researchers and clinicians battling bacterial infections. However, little is known about the uptake of the Ag NPs into the bacteria, the related uptake mechanisms, and how they are connected to antimicrobial activity. Even less information is available on AgAu alloy NPs uptake.

View Article and Find Full Text PDF

An interactive simulation of a transmission electron microscope (TEM) called is developed here, which enables users to understand how to operate and control an electron beam without the need to access an instrument. allows users to familiarize themselves with alignment procedures offline, reducing the time and money required to become a proficient TEM operator. In addition to teaching the basics of electron beam alignments, the software enables users to create bespoke microscope configurations and develop an understanding of how to operate the configurations without sitting at a microscope.

View Article and Find Full Text PDF

Cryogenic electron microscopy can provide high-resolution reconstructions of macromolecules embedded in a thin layer of ice from which atomic models can be built . However, the interaction between the ionizing electron beam and the sample results in beam-induced motion and image distortion, which limit the attainable resolutions. Sample charging is one contributing factor of beam-induced motions and image distortions, which is normally alleviated by including part of the supporting conducting film within the beam-exposed region.

View Article and Find Full Text PDF

The hallmark of spintronics has been the ability of spin-orbit interactions to convert a charge current into a spin current and vice versa, mainly in the bulk of heavy metal thin films. Here, we demonstrate how a light metal interface profoundly affects both the nature of spin-orbit torques and its efficiency in terms of damping-like () and field-like () effective fields in ultrathin Co films. We measure unexpectedly / ratios much larger than 1 by inserting a nanometer-thin Al metallic layer in Pt|Co|Al|Pt as compared to a similar stacking, including Cu as a reference.

View Article and Find Full Text PDF

Functional materials feature hierarchical microstructures that define their unique set of properties. The prediction and tailoring of these require a multiscale knowledge of the mechanistic interaction of microstructure and property. An important material in this respect is biodegradable magnesium alloys used for implant applications.

View Article and Find Full Text PDF

Quantitative electric field mapping between electrically biased needles by scanning transmission electron microscopy and electron holography.

Ultramicroscopy

November 2023

Department of Chemistry and Centre for NanoScience, Ludwig-Maximilians-Universität München, Butenandtstrasse 11, 81377 Munich, Germany; Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, 52425 Jülich, Germany. Electronic address:

Stray electric fields in free space generated by two biased gold needles have been quantified in comprehensive finite-element (FE) simulations, accompanied by first moment (FM) scanning TEM (STEM) and electron holography (EH) experiments. The projected electrostatic potential and electric field have been derived numerically under geometrical variations of the needle setup. In contrast to the FE simulation, application of an analytical model based on line charges yields a qualitative understanding.

View Article and Find Full Text PDF

Pseudomonas species have become promising cell factories for the production of natural products due to their inherent robustness. Although these bacteria have naturally evolved strategies to cope with different kinds of stress, many biotechnological applications benefit from engineering of optimised chassis strains with specially adapted tolerance traits. Here, we explored the formation of outer membrane vesicles (OMV) of Pseudomonas putida KT2440.

View Article and Find Full Text PDF

Magnetoelasticity is the bond between magnetism and mechanics, but the intricate mechanisms via which magnetic states change due to mechanical strain remain poorly understood. Here, we provide direct nanoscale observations of how tensile strain modifies magnetic domains in a ferromagnetic Ni thin plate using in situ Fresnel defocus imaging, off-axis electron holography and a bimetallic deformation device. We present quantitative measurements of magnetic domain wall structure and its transformations as a function of strain.

View Article and Find Full Text PDF

Structure determination of biological macromolecules using cryogenic electron microscopy is based on applying the phase object (PO) assumption and the weak phase object (WPO) approximation to reconstruct the 3D potential density of the molecule. To enhance the understanding of image formation of protein complexes embedded in glass-like ice in a transmission electron microscope, this study addresses multiple scattering in tobacco mosaic virus (TMV) specimens. This includes the propagation inside the molecule while also accounting for the effect of structural noise.

View Article and Find Full Text PDF

We have investigated magnetism of the AlCoCrFeNi single-crystalline high-entropy alloy. The material is nanostructured, composed of a B2 matrix with dispersed spherical-like A2 nanoparticles of average diameter 64 nm. The magnetism was studied from 2 to 400 K via direct-current magnetization, hysteresis curves, alternating-current magnetic susceptibility, and thermoremanent magnetization time decay, to determine the magnetic state that develops in this highly structurally and chemically inhomogeneous material.

View Article and Find Full Text PDF

Dual-phase membranes are increasingly attracting attention as a solution for developing stable oxygen permeation membranes. CeGdO-FeCoO (CGO-F(3-x)CxO) composites are one group of promising candidates. This study aims to understand the effect of the Fe/Co-ratio, i.

View Article and Find Full Text PDF

The essential ATPase MsbA is a lipid flippase that serves as a prototype for multi drug resistant ABC transporters. Its physiological function is the transport of lipopolisaccharides to build up the outer membranes of Gram-negative bacteria. Although several structural and biochemical studies of MsbA have been conducted previously, a detailed picture of the dynamic processes that link ATP hydrolysis to allocrit transport remains elusive.

View Article and Find Full Text PDF

Poly(ethylene oxide) block copolymers (PEO BCP) have been demonstrated to exhibit remarkably high lithium ion (Li) conductivity for Li batteries applications. For linear poly(isoprene)--poly(styrene)--poly(ethylene oxide) triblock copolymers (PIPSPEO), a pronounced maximum ion conductivity was reported for short PEO molecular weights around 2 kg mol. To later enable a systematic exploration of the influence of the PI and PS block lengths and related morphologies on the ion conductivity, a synthetic method is needed where the short PEO block length can be kept constant, while the PI and PS block lengths could be systematically and independently varied.

View Article and Find Full Text PDF

Liquid-phase transmission electron microscopy (LPTEM) technique has been used to perform a wide range of in situ and operando studies. While most studies are based on the sample contrast change in the liquid, acquiring high qualitative results in the native liquid environment still poses a challenge. Herein, we present a novel and facile method to perform high-resolution and analytical electron microscopy studies in a liquid flow cell.

View Article and Find Full Text PDF

TEMGYM Advanced: Software for electron lens aberrations and parallelised electron ray tracing.

Ultramicroscopy

August 2023

Department of Chemistry, University College London, 20 Gordon St, London, WC1H 0AJ, United Kingdom. Electronic address:

Characterisation of the electron beams trajectory in an electron microscope is possible in a few select commercial software packages, but these tools and their source code are not available in a free and accessible manner. This paper introduces the free and open-source software TEMGYM Advanced, which implements ray tracing methods that calculate the path of electrons through a magnetic or electrostatic lens and allow evaluation of the first-order properties and third-order geometric aberrations. Validation of the aberration coefficient calculations is performed by implementing two independent methods - the aberration integral and differential algebra (DA) methods and by comparing the results of each.

View Article and Find Full Text PDF

Dynamin-like proteins are membrane remodeling GTPases with well-understood functions in eukaryotic cells. However, bacterial dynamin-like proteins are still poorly investigated. SynDLP, the dynamin-like protein of the cyanobacterium Synechocystis sp.

View Article and Find Full Text PDF