Publications by authors named "Alexander Bjorling"

Pleomorphic adenoma (PA) most commonly manifests in the parotid gland, though it occasionally emerges in atypical locations. We present a case involving an 87-year-old female who exhibited chronic left-sided nasal symptoms, leading to the diagnosis of PA in the nasal cavity. This diagnosis was confirmed through rhinoscopy and subsequent pathological examination following the surgical excision of an 8x8 mm mass.

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Bragg coherent X-ray diffraction imaging (BCDI) has emerged as a powerful technique for strain imaging and morphology reconstruction of nanometre-scale crystals. However, BCDI often suffers from angular distortions that appear during data acquisition, caused by radiation pressure, heating or imperfect scanning stages. This limits the applicability of BCDI, in particular for small crystals and high-flux X-ray beams.

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In this case report, we detail a rare instance of sialadenitis secondary to bilateral hypertrophic torus mandibularis (TM) in a 70-year-old Caucasian male who presented with neck swelling, dysphagia, and weight loss. Radiographic evaluations revealed enlarged TM obstructing Wharton's duct, further complicated by a sialolith. The patient's treatment regimen included antibiotics, oral steroids, and sialogogues, accompanied by surgical removal of the hypertrophic TM and sialoendoscopy, which resulted in significant symptomatic relief and the resolution of sialadenitis.

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Fishbone foreign body (FFB) can lodge in the upper respiratory or gastrointestinal tracts and frequently cause discomfort. While FFBs are common, variations in the hyoid may present radiographically similarly. The authors present a case in which a 32-year-old woman presented with pain in the right neck with a globus sensation after eating fish.

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Developing semiconductor devices requires a fast and reliable source of strain information with high spatial resolution and strain sensitivity. This work investigates the strain in an axially heterostructured 180 nm-diameter GaInP nanowire with InP segments of varying lengths down to 9 nm, simultaneously probing both materials. Scanning X-ray diffraction (XRD) is compared with Bragg projection ptychography (BPP), a fast single-projection method.

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Metal halide perovskites (MHPs) have garnered significant interest as promising candidates for nanoscale optoelectronic applications due to their excellent optical properties. Axially heterostructured CsPbBr-CsPb(BrCl) nanowires can be produced by localized anion exchange of pregrown CsPbBr nanowires. However, characterizing such heterostructures with sufficient strain and real space resolution is challenging.

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Bacterial colonization is mediated by fimbriae, which are thin hair-like appendages dispersed from the bacterial surface. The aggregative adherence fimbriae from enteroaggregative E. coli are secreted through the outer membrane and consist of polymerized minor and major pilin subunits.

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Resolving the structural dynamics of bond breaking, bond formation, and solvation is required for a deeper understanding of solution-phase chemical reactions. In this work, we investigate the photodissociation of triiodide in four solvents using femtosecond time-resolved X-ray solution scattering following 400 nm photoexcitation. Structural analysis of the scattering data resolves the solvent-dependent structural evolution during the bond cleavage, internal rearrangements, solvent-cage escape, and bond reformation in real time.

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Serial femtosecond crystallography was initially developed for room-temperature X-ray diffraction studies of macromolecules at X-ray free electron lasers. When combined with tools that initiate biological reactions within microcrystals, time-resolved serial crystallography allows the study of structural changes that occur during an enzyme catalytic reaction. Serial synchrotron X-ray crystallography (SSX), which extends serial crystallography methods to synchrotron radiation sources, is expanding the scientific community using serial diffraction methods.

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We demonstrate how the individual mirrors of a high-quality Kirkpatrick-Baez (KB) mirror system can be aligned to each other to create an optimally focused beam, through minimizing aberrations in the phase of the ptychographically reconstructed pupil function. Different sources of misalignment and the distinctive phase artifacts they create are presented via experimental results from the alignment of the KB mirrors at the NanoMAX diffraction endstation. The catalog of aberration artifacts can be used to easily identify which parameter requires further tuning in the alignment of any KB mirror system.

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The diffraction endstation of the NanoMAX beamline is designed to provide high-flux coherent X-ray nano-beams for experiments requiring many degrees of freedom for sample and detector. The endstation is equipped with high-efficiency Kirkpatrick-Baez mirror focusing optics and a two-circle goniometer supporting a positioning and scanning device, designed to carry a compact sample environment. A robot is used as a detector arm.

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Correction for 'Strain mapping inside an individual processed vertical nanowire transistor using scanning X-ray nanodiffraction' by Dmitry Dzhigaev , , 2020, , 14487-14493, DOI: 10.1039/D0NR02260H.

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Efficient manipulation of antiferromagnetic (AF) domains and domain walls has opened up new avenues of research towards ultrafast, high-density spintronic devices. AF domain structures are known to be sensitive to magnetoelastic effects, but the microscopic interplay of crystalline defects, strain and magnetic ordering remains largely unknown. Here, we reveal, using photoemission electron microscopy combined with scanning X-ray diffraction imaging and micromagnetic simulations, that the AF domain structure in CuMnAs thin films is dominated by nanoscale structural twin defects.

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The combination of strain and electrostatic engineering in epitaxial heterostructures of ferroelectric oxides offers many possibilities for inducing new phases, complex polar topologies, and enhanced electrical properties. However, the dominant effect of substrate clamping can also limit the electromechanical response and often leaves electrostatics to play a secondary role. Releasing the mechanical constraint imposed by the substrate can not only dramatically alter the balance between elastic and electrostatic forces, enabling them to compete on par with each other, but also activates new mechanical degrees of freedom, such as the macroscopic curvature of the heterostructure.

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The CoSAXS beamline at the MAX IV Laboratory is a modern multi-purpose (coherent) small-angle X-ray scattering (CoSAXS) instrument, designed to provide intense and optionally coherent illumination at the sample position, enabling coherent imaging and speckle contrast techniques. X-ray tracing simulations used to design the beamline optics have predicted a total photon flux of 10-10 photons s and a degree of coherence of up to 10% at 7.1 keV.

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NanoMAX is the first hard X-ray nanoprobe beamline at the MAX IV laboratory. It utilizes the unique properties of the world's first operational multi-bend achromat storage ring to provide an intense and coherent focused beam for experiments with several methods. In this paper we present the beamline optics design in detail, show the performance figures, and give an overview of the surrounding infrastructure and the operational diffraction endstation.

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The emergence of fourth-generation synchrotrons is prompting the development of new systems for experimental control and data acquisition. However, as general control systems are designed to cover a wide set of instruments and techniques, they tend to become large and complicated, at the cost of experimental flexibility. Here we present Contrast, a simple Python framework for interacting with beamline components, orchestrating experiments and managing data acquisition.

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Unconventional ferroelectricity exhibited by hafnia-based thin films-robust at nanoscale sizes-presents tremendous opportunities in nanoelectronics. However, the exact nature of polarization switching remains controversial. We investigated a LaSrMnO/HfZrO capacitor interfaced with various top electrodes while performing in situ electrical biasing using atomic-resolution microscopy with direct oxygen imaging as well as with synchrotron nanobeam diffraction.

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Bragg coherent diffraction imaging is a powerful strain imaging tool, often limited by beam-induced sample instability for small particles and high power densities. Here, we devise and validate an adapted diffraction volume assembly algorithm, capable of recovering three-dimensional datasets from particles undergoing uncontrolled and unknown rotations. We apply the method to gold nanoparticles which rotate under the influence of a focused coherent x-ray beam, retrieving their three-dimensional shapes and strain fields.

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Ptychographic X-ray computed tomography is a quantitative three-dimensional imaging technique offered to users of multiple synchrotron radiation sources. Its dependence on the coherent fraction of the available X-ray beam makes it perfectly suited to diffraction-limited storage rings. Although MAX IV is the first, and so far only, operating fourth-generation synchrotron light source, none of its experimental stations is currently set up to offer this technique to its users.

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Nanoscale X-ray detectors could allow higher resolution in imaging and diffraction experiments than established systems but are difficult to design due to the long absorption length of X-rays. Here, we demonstrate X-ray detection in a single nanowire in which the nanowire axis is parallel to the optical axis. In this geometry, X-ray absorption can occur along the nanowire length, while the spatial resolution is limited by the diameter.

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The interest in metal halide perovskites has grown as impressive results have been shown in solar cells, light emitting devices, and scintillators, but this class of materials have a complex crystal structure that is only partially understood. In particular, the dynamics of the nanoscale ferroelastic domains in metal halide perovskites remains difficult to study. An ideal imaging method for ferroelastic domains requires a challenging combination of high spatial resolution and long penetration depth.

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Semiconductor nanowires in wrapped, gate-all-around transistor geometry are highly favorable for future electronics. The advanced nanodevice processing results in strain due to the deposited dielectric and metal layers surrounding the nanowires, significantly affecting their performance. Therefore, non-destructive nanoscale characterization of complete devices is of utmost importance due to the small feature sizes and three-dimensional buried structure.

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The NanoMAX hard X-ray nanoprobe is the first beamline to take full advantage of the diffraction-limited storage ring at the MAX IV synchrotron and delivers a high coherent photon flux for applications in diffraction and imaging. Here, we characterize its coherent and focused beam using ptychographic analysis. We derive beam profiles in the energy range 6-22 keV and estimate the coherent flux based on a probe mode decomposition approach.

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Article Synopsis
  • Nanoparticles are crucial in various fields like chemical production and energy conversion, but developing effective catalysts depends on understanding their structure and reactivity.
  • Recent advancements in Bragg coherent diffraction imaging offer a way to visualize three-dimensional lattice strain fields, which can help create surface reactivity maps for nanoparticles.
  • New research at the MAX IV facility demonstrated the imaging of 60 nm gold nanoparticles, showing that their capabilities are sufficient for studying smaller particles essential for catalysis, marking a significant advancement in coherent X-ray diffraction techniques.
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