E01-JEM ARM 200CF
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Emerson C.
Kohlrausch
,
Christopher
Leist
,
Gazi N.
Aliev
,
Mohsen
Danaie
,
Matthew
Young
,
Madasamy
Thangamuthu
,
Yifan
Chen
,
William J.
Cull
,
Wolfgang
Theis
,
Ute
Kaiser
,
Andrei N.
Khlobystov
,
Jesum
Alves Fernandes
Diamond Proposal Number(s):
[37379, 38763]
Abstract: Understanding how catalytically active sites emerge and evolve under working conditions is a fundamental challenge that limits the rational design of heterogeneous catalysts. Here, we directly visualize the transformation between alloyed PtNi and phase-separated Pt-NiO nanoclusters during hydrogen evolution. Using in situ low-voltage aberration-corrected electron microscopy, with the electron beam serving as both the stimulus and probe, we track the formation of active sites under low-water-vapor conditions. PtNi nanoclusters were assembled with controlled mixing of the atoms, resulting in two distinct configurational entropy states. Under reaction conditions, the transformation of bimetallic nanoclusters shifts from an entropically stabilized alloy to an enthalpically favored phase-separated configuration, controlled by oxygen availability and by a critical nucleus size. The atomic dynamics observed in real space correlate directly with catalytic performance, where the low-entropy Pt-NiO state achieves a record hydrogen evolution mass activity of 11.1 A/mgPt due to a high density of interfacial sites that promote water dissociation on NiO and efficient hydrogen adsorption on Pt atoms.
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Jun 2026
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Krios III-Titan Krios III at Diamond
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Ho Fong
Leong
,
Giovanni
Consoli
,
Geoffry A.
Davis
,
Ben
Hancox-Lachman
,
Kenta
Renard
,
Fiazall
Tufail
,
Lauren E.
Lee
,
Lucas
Gautier
,
James W.
Murray
,
Andrea
Fantuzzi
,
A. William
Rutherford
Diamond Proposal Number(s):
[33230]
Open Access
Abstract: Far-red light photoacclimation enables some cyanobacteria to survive in white-light-depleted environments by extending the red limit of photosynthesis. In far-red Photosystem II, paralogous subunits replace their canonical counterparts, allowing the incorporation of some chlorophyll f molecules and one chlorophyll d that are red-shifted and spectrally distinct from the chlorophyll a manifold, and from each other. Here, we present a comparative study of far-red Photosystem II from Chroococcidiopsis thermalis PCC 7203 and Calothrix sp. NIES-3974. In C. thermalis, the cryo-electron microscopy structure reveals the far-red-exclusive subunit, PsbH2’, which forms part of a chlorophyll f binding site. We also assign four chlorophyll f sites using sequence comparisons and electrostatic potential analyses. In Calothrix, psbH2’ is absent, and the same analyses show that only two of these chlorophyll f sites are present. Comparative phylogenetic, structural, and spectroscopic analyses allow the assignment of specific wavelengths to all the red-shifted chlorophylls. This provides the framework needed to model excitation energy transfer in far-red Photosystem II, and to understand the conserved features that allow survival under far-red light.
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Jun 2026
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Krios I-Titan Krios I at Diamond
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Diamond Proposal Number(s):
[37221]
Open Access
Abstract: Biocatalytic cascades offer a promising route for CO2-fixation into valuable chemicals, addressing the urgent need for efficient, sustainable technologies to reduce CO2 emissions. This paper describes an enzymatic route converting gaseous CO2 and acetaldehyde into enantiopure lactic acid, widely used in diverse industries. A newly characterized pyruvate decarboxylase from Neoasia chiangmaiensis (NcPDC) enabled acetaldehyde carboxylation to pyruvate. To suppress the competing carboligation to acetoin, acetaldehyde was reversibly trapped with Tris. Pyruvate was reduced to lactate by lactate dehydrogenase, coupled with glucose dehydrogenase for NADH regeneration via D-glucose oxidation to D-gluconic acid. Up to 65% lactate yield was achieved. Repeated acetaldehyde dosing resulted in a 27 mM titer, representing a >100-fold improvement over previous reports. At 0.5 L scale, using a gas mixture mimicking industrial-grade CO2, we obtained 21 mM D-(–)-lactic acid, 42% yield and >98% e.e., demonstrating scalability and robustness. Finally, replacing the D-(–)-selective lactate dehydrogenase with an L-(+)-selective variant at small scale enabled production of L-(+)-lactic acid at 41% yield and >93% e.e, allowing switchable access to either enantiomer. A volumetric productivity of 1.1 × 10−2 g L−1 h−1 ranks among the most efficient minimal enzymatic routes developed to date for CO2-to-lactate conversion.
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Jun 2026
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B16-Test Beamline
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Diamond Proposal Number(s):
[36299, 34545]
Open Access
Abstract: This study investigates the lattice strain induced by Ge:Sb alloy films on Ge substrates. Metastable films are formed by UV pulsed laser melting (PLM) of a Sb-coated Ge substrate. We fabricate thin Ge:Sb layers, systematically varying processing parameters and crystal orientation to study strain and strain-relaxation-induced defects. High-resolution X-Ray diffraction and electrical characterization revealed extremely high strain values as well as ultra-low resistivity induced by Sb. Maximum strain before the onset of strain relaxation was found to depend on crystal orientation with the Ge (1 1 1) orientation yielding the highest strain values. By combining structural as well as electrical information, we estimated Sb contribution to lattice expansion, separating electronically active from inactive fractions. Strain optimization was applied to an innovative application that is the production of bent crystals for high energy particle beam deflection and radiation production. Bending tests on thin Ge substrates confirmed the method, with controlled PLM processing allowing inducing quantifiable curvature with smallest achievable radii of 4.5 m. Exploiting non-equilibrium doping/alloying to exceed equilibrium Sb solubility is promising for applications ranging from ultra-low-resistivity layers in scaled nano-electronic devices to bent crystals for advanced systems like crystal-based undulators, enabling new approaches to high-energy photon production.
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Jun 2026
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Krios I-Titan Krios I at Diamond
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Carys
Williams
,
Laura M.
Nocka
,
George
Hedger
,
Pragya
Parashara
,
Els
Pardon
,
Naomi R.
Latorraca
,
Ganesh V.
Pusapati
,
Parijat
Sarkar
,
Dorothy
Lartey
,
Lei
Gao
,
Ljiljana
Milenkovic
,
Rod
Chalk
,
Jan
Steyaert
,
Susan
Marqusee
,
Loic
Carrique
,
J. Fernando
Bazan
,
Sarah L.
Rouse
,
Jennifer H.
Kong
,
Christian
Siebold
,
Rajat
Rohatgi
Diamond Proposal Number(s):
[28713]
Open Access
Abstract: Receptor-type E3 ubiquitin ligases enable extracellular signals to control ubiquitylation in the cytoplasm, playing widespread roles in development, metabolism, and immunity. Using cryoelectron microscopy, integrated with biophysical and functional studies, we visualized a human E3 complex composed of two transmembrane proteins, MEGF8 and MOSMO, and the intracellular RING-family protein MGRN1. This MEGF8-MOSMO-MGRN1 (MMM) complex attenuates Hedgehog signaling by ubiquitylating Smoothened (SMO), a G-protein-coupled receptor (GPCR) that transduces morphogen signals. A long helix in the MMM complex engages SMO using an intramembrane degron and extends into the cytoplasm to suspend an activated and precisely oriented RING domain below the plasma membrane. This architecture enables ubiquitylation of the cytoplasmic surface of SMO, reducing SMO abundance at primary cilia. Our structure provides insights into MEGF8 mutations, which cause multi-organ birth defects, and defines a paradigm for how transmembrane E3 ligases control the cell surface abundance of GPCRs and other signaling receptors.
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Jun 2026
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Krios IV-Titan Krios IV at Diamond
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Diamond Proposal Number(s):
[25452, 32707]
Open Access
Abstract: Antimicrobial resistance is driving the search for new antibiotics and a greater understanding of their mechanism of action. Doxycycline is amongst the most-prescribed antimicrobials. It demonstrates a particularly low minimum inhibitory concentration against the zoonotic pathogen Coxiella burnetii. Doxycycline canonically targets the bacterial ribosome by blocking tRNA binding at the decoding centre (A site) of the small subunit. Using cryo-electron microscopy, we analysed doxycycline binding to C. burnetii and Escherichia coli ribosomes. Both structures reveal doxycycline binding at the exit tunnel in the large subunit. In C. burnetii three doxycycline molecules stack to block the tunnel. In E. coli one doxycycline molecule triggers a major change in the conformation of the ribosome. This rearrangement of the peptidyl transferase centre blocks tRNA binding and nascent chain accommodation, abolishing interactions that are fundamental to ribosome function. We identify a distinct ribosomal protein in the C. burnetii large subunit and characterise an additional member of the prokaryotic ribosome hibernation-promoting factor family. These insights into ribosome function and antibiotic action may aid the development of new ribosome inhibitor antibiotics.
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Jun 2026
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E02-JEM ARM 300CF
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Christopher J. H.
Smalley
,
Colan E.
Hughes
,
Tom
Willhammar
,
Raj
Pandya
,
Semion K.
Saikin
,
Duncan N.
Johnstone
,
Jeffrey
Gorman
,
Jooyoung
Sung
,
Gianni
Jacucci
,
Paul A.
Midgley
,
Demie M.
Kepaptsoglou
,
Quentin M.
Ramasse
,
Akshay
Rao
,
Kenneth D. M.
Harris
,
Sean M.
Collins
Diamond Proposal Number(s):
[20527]
Open Access
Abstract: Organic semiconductors continue to make substantial performance gains from photovoltaics to electronics. However, understanding how differences in solid-state structure give rise to large differences in energy transport properties remains unresolved. We report that microcrystals of two perylene diimide (PDI) derivatives differing only in their terminal groups [cyclohexyl (CH) and 4-heptyl (ST)] have exciton diffusion coefficients differing by more than two orders of magnitude. Applying state-of-the-art techniques for microcrystal structure determination, we report the crystal structures of CH-PDI and two polymorphs of ST-PDI. Scanning electron diffraction reveals a range of crystallographic defects in ST-PDI microcrystals, attributed to polymorph intergrowths, while electron energy loss spectroscopy links these defects to nanoscale electronic structure changes. Computational modeling demonstrates that rotational disorder explains the difference in exciton diffusion coefficients. Our observations establish the importance of defect-induced orientational disorder as a source of extrinsic energetic disorder, highlighting the need for defect management in organic semiconductor technologies.
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May 2026
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E01-JEM ARM 200CF
I13-1-Coherence
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Diamond Proposal Number(s):
[39271]
Open Access
Abstract: Multi-material structures have shown great versatility in wide applications. However, additive manufacturing of multi-metal mechanical composite structures is challenging. Beyond this, a comprehensive and multi-scale understanding of the fracture mechanisms in such structures has not been sufficiently elucidated. In this study, we exploited synchrotron phase contrast X-ray computed tomography and synchrotron X-ray ptychographic tomography to achieve in situ, continuous observation of the fracturing process in large-scale brick-and-mortar multi-metal composite structures, resolving phenomena spanning from the micro- to nano- scale. Findings suggest that nano-pores prevailingly exist in additively manufactured metals, and interfacial porosity as a transitional geometry between different materials can retard the crack growth and improve fracture toughness. This multi-scale study directly informs the designing, manufacturing, and testing of multi-metal composite structures.
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May 2026
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Krios III-Titan Krios III at Diamond
Krios IV-Titan Krios IV at Diamond
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Douglas S. M.
Ferreira
,
Katie
Mclennan
,
Calum
Diamond
,
Melanie
Vollmar
,
Wasim
Kiyani
,
D. Sean
Froese
,
Jola
Kopec
,
Henry J.
Bailey
,
Rod
Chalk
,
Arnaud
Basle
,
Jonathan M.
Elkins
,
Jesse
Coker
,
Wyatt W.
Yue
,
Thomas J.
Mccorvie
Diamond Proposal Number(s):
[34172]
Open Access
Abstract: Human methionine synthase (MTR) is an essential enzyme of one carbon metabolism. Consisting of a catalytic N-half and a cobalamin binding C-half, MTR utilises this intricate organometallic cofactor in the methyl transfer from methyltetrahydrofolate to homocysteine producing methionine. Cobalamin loading into MTR, and its subsequent activation, requires methylmalonic aciduria and homocystinuria Type D (MMADHC) protein and methionine synthase reductase (MTRR), respectively. However, the molecular basis of cobalamin binding and activation of human MTR aided by MMADHC and MTRR remains unknown. Here, using cryo-electron microscopy, we determine structures of human MTR in its apo, and cobalamin bound states. Apo MTR adopts a conformation where the two halves of the enzyme act independently with the C-half posed to bind cobalamin. Binding of cobalamin and its activation causes conformational changes in MTR that result in a flexible catalytically active state. AlphaFold predictions, validated by interaction studies, show that MMADHC interacts with the C-half of apo MTR to facilitate cobalamin loading. Unexpectedly we found that MTRR interacts at two distinct sites within the C-half of MTR which may aid in activation. Collectively these findings lay the groundwork to uncover the mechanisms through how MMADHC and MTRR coordinate cobalamin loading and activation of human MTR.
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May 2026
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I06-Nanoscience (XPEEM)
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Diamond Proposal Number(s):
[6230, 1771]
Open Access
Abstract: Epitaxial films of the ferromagnetic manganite La0.7Sr0.3MnO3 on substrates of the ferroelectric perovskite BaTiO3 are known to display sharp magnetic changes and large magnetoelectric effects when the film is strained by the substrate undergoing thermally driven structural transitions and ferroelectric domain switching, respectively. However, only a single component of the in-plane magnetization has been hitherto imaged. Here we present magnetic vector maps—obtained from photoemission electron microscopy images with magnetic contrast from x-ray magnetic circular dichroism—to show that the electrically and thermally driven changes of local and global magnetization are deterministically influenced by the state of the substrate while also being complex and sample dependent. Our findings, supported by ferromagnetic resonance data and vibrating sample magnetometry, reveal that the behavior of La0.7Sr0.3MnO3 films on BaTiO3 substrates is not well predicted from knowledge of each system, probably due to long-range strain between BaTiO3 domains. In the future, it would be interesting to reduce complexity by patterning the film into regions between which magnetic communication is negligible.
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May 2026
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