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Haoran
Ma
,
J. Pedro F.
Nunes
,
Ambar
Banerjee
,
Martin
Centurion
,
Kareem
Hegazy
,
Renkai
Li
,
Yusong
Liu
,
Xiaozhe
Shen
,
Xijie
Wang
,
Stephen
Weathersby
,
Philippe
Wernet
,
Thomas J. A.
Wolf
,
Michael
Odelius
,
Jie
Yang
Open Access
Abstract: The structural dynamics of metal carbonyls are central to processes ranging from catalysis to organometallic synthesis. Here we investigate the photodissociation of a prototypical transition metal carbonyl, Fe(CO)5, using mega-electron-volt ultrafast electron diffraction. By separately tracking structural evolution along the axial and equatorial directions, we provide an atomistic, angle-resolved view of the nuclear motions preceding CO dissociation and infer key features of the excited-state potential energy surface from the experimental observations. We further show that vibrational coupling before reaching the conical intersection facilitates the loss of a random carbonyl ligand via the Berry pseudorotation mechanism.
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Jun 2026
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I21-Resonant Inelastic X-ray Scattering (RIXS)
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Xin
Zhang
,
Qiyun
Wang
,
Qi
Zhang
,
Haoyin
Zhong
,
Chao
Wu
,
Baorui
Jia
,
Junchen
Yu
,
Ke-Jin
Zhou
,
Yuanjie
Li
,
Yong-Wei
Zhang
,
Zhi Gen
Yu
,
Shibo
Xi
,
Xiaopeng
Wang
,
Junmin
Xue
Diamond Proposal Number(s):
[35048]
Open Access
Abstract: Introducing oxygen redox chemistry into cobalt oxyhydroxide effectively enhances catalytic activity by enabling direct O-O coupling, thereby bypassing the rate-limiting *OOH step in the conventional adsorbate evolution mechanism. However, the key challenge is to preserve the accessibility of non-bonding oxygen states while maintaining cobalt-oxygen covalency. Here we show that light irradiation triggers ligand-to-metal charge transfer in sulfur-treated cobalt oxyhydroxide (S-CoOOH), generating non-bonding oxygen states. These states then couple with adjacent ones to form direct O-O bonds. Through this way, the sulfur-treated sample performs enhanced OER activity under light, achieving an overpotential of 194 ± 3 mV at 10 mA cm−2, which is 41 mV lower than in the dark. Further analysis reveals that light-induced oxygen redox activity is confined to the edge of catalyst. This activity originates from electron transitions from (M-O) to non-overlapping regions of Co 3 d and 4p orbitals, driven by high-spin Co3+ at the edge. This work highlights the critical role of light in inducing non-bonding oxygen states in transition metal-based catalysts and guides the development of oxygen-redox electrocatalysts.
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Jun 2026
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I12-JEEP: Joint Engineering, Environmental and Processing
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Barbara
Bonechi
,
Fabio
Arzilli
,
Margherita
Polacci
,
Alessandro
Fabbrizio
,
Giuseppe
La Spina
,
Eleni
Michailidou
,
Elisa
Biagioli
,
Richard A.
Brooker
,
Jean-Louis
Hazemann
,
Robert C.
Atwood
,
Danilo
Di Genova
,
Sumith
Abeykoon
,
David A.
Neave
,
Renat R.
Almeev
,
Mike
Burton
Diamond Proposal Number(s):
[31529]
Open Access
Abstract: Crystallisation kinetics play a fundamental role in controlling conduit dynamics and eruptive style. The degree of superheating is critical in controlling crystallisation kinetics; however, its effect is still debated and has an unclear impact on eruption dynamics. Here, we investigate how superheating influences clinopyroxene nucleation in tephritic magmas from the 2021 Tajogaite eruption (La Palma, Spain) through both in situ and ex situ view experiments. Our findings show that superheating delays nucleation by dissolving pre-existing nuclei, thereby inhibiting crystallisation upon return to subliquidus conditions. Using a numerical model, we investigate how different nucleation delays resulting from different degrees of superheating affect magma ascent dynamics. Depending on the initial thermodynamic conditions and on the pre-eruptive history of magma, an increased nucleation delay can significantly reduce crystal content during ascent, lowering magma viscosity and affecting eruptive style. These findings highlight the critical role of pre-eruptive thermal histories in controlling eruptive style, and provide constraints for refining experimental protocols and numerical models, with direct implications for improving volcanic hazard assessment and eruption forecasting.
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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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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Julian M.
Ludäscher
,
Emma
Scaletti Hutchinson
,
Guillem
Vila-Julià
,
Ann-Sofie
Jemth
,
Saher
Shahid
,
Elisee
Wiita
,
Israel
Cabeza De Vaca
,
Szymon
Pach
,
Lukas
Gajdos
,
Swati
Aggarwal
,
Ellen
Walse
,
Oliver
Mortusewicz
,
Thomas
Helleday
,
Jens
Carlsson
,
Pal
Stenmark
Diamond Proposal Number(s):
[29948]
Open Access
Abstract: Human single-strand-selective monofunctional uracil DNA glycosylase 1 (hSMUG1) removes uracil, 5-hydroxymethyluracil (5hmU) and 5-fluorouracil (5FU) from DNA, thereby initiating the base excision repair (BER) process. hSMUG1 is important for maintaining genomic integrity and plays a significant role in cancer biology. Here, we present the structures of hSMUG1, including complexes with products (uracil and 5FU) and an enzyme-product complex of hSMUG1 with double-stranded DNA (dsDNA). Analysis of our hSMUG1-dsDNA complex reveals how uracil is flipped out of the dsDNA for excision and identifies key residues that we confirm to be critical for both DNA binding and enzymatic activity. Furthermore, our hSMUG1 substrate complexes, molecular dynamics simulations and neutron diffraction data suggest a mechanism by which the substrate uracil rotates following base excision. The structural and functional information presented here will be highly useful for the future development of inhibitors and/or activators targeting hSMUG1.
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Jun 2026
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I05-ARPES
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Junhyeok
Jeong
,
Yamato
Enomoto
,
Yoshimitsu
Kohama
,
Tomotaka
Nakayama
,
Kotaro
Ando
,
Kifu
Kurokawa
,
Soonsang
Huh
,
Zhuo
Yang
,
Toshihiro
Nomura
,
Matthew D.
Watson
,
Timur K.
Kim
,
Cephise
Cacho
,
Chun
Lin
,
Makoto
Hashimoto
,
Donghui
Lu
,
Shiro
Sakai
,
Takami
Tohyama
,
Kazuyasu
Tokiwa
,
Takeshi
Kondo
Diamond Proposal Number(s):
[36822, 30646, 28930, 25416]
Open Access
Abstract: Fermi arcs observed in underdoped cuprates have sparked debate over whether they represent segments of a large Fermi surface or small Fermi pockets. This ambiguity has long hindered their classification as either the conventional Bardeen-Cooper-Schrieffer (BCS) regime or the strongly coupled Bose-Einstein condensation (BEC) crossover limit. Here, using angle-resolved photoemission spectroscopy and quantum oscillations, we demonstrate the coexistence of a small Fermi pocket and a large superconducting gap in the clean inner CuO2 layers of the four-layer cuprate Ba2Ca3Cu4O8(F,O)2. This coexistence constitutes a hallmark of the BCS-BEC crossover and has remained elusive for decades. Despite the presence of antiferromagnetic (AF) order, the superconducting gap in the small pocket is remarkably large, yielding a gap-to-Fermi energy ratio (Δpocket/εF ~ 0.6) and a critical-to-Fermi temperature ratio (Tc/TF ~ 0.13) that reach the theoretical upper bound for two-dimensional superconductivity. Unexpectedly, this BCS-BEC crossover emerges not as the carrier density decreases but as it increases, abruptly within a narrow doping range of less than 1%. These results provide a long-sought microscopic foundation for the d-wave pairing mechanism in doped AF-Mott insulators.
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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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I03-Macromolecular Crystallography
|
Benjamin T. W.
Schwabe
,
Isabelle M.
Angstman
,
Katharina
Vollheyde
,
Zoe
Ingold
,
Jiacheng
Li
,
Ksenia S.
Stankevich
,
Christopher D.
Spicer
,
Martin A.
Fascione
,
Gideon
Grogan
,
Fernando
Geu-Flores
,
Benjamin R.
Lichman
Diamond Proposal Number(s):
[24948]
Open Access
Abstract: Nicotine is a neuroactive alkaloid produced by tobacco (Nicotiana tabacum) as a defence against herbivory, and an addictive stimulant that has been used by humans for millennia. Despite its significance, the core steps of its biosynthesis have remained elusive. Here, we demonstrate the in vitro reconstruction of a four-enzyme stereoselective biocatalytic cascade that forms (S)-nicotine from nicotinic acid and N-methylpyrrolinium. This cascade includes two glucose-processing enzymes that participate in a cryptic activating glucosylation step. We also reconstruct this pathway in planta and present high resolution X-ray structures of the key carbon-carbon bond forming reductase-oxidase pair bound to their substrate and product, respectively. This work establishes the complete biosynthetic pathway to nicotine, providing new gene targets for controlling alkaloid production in Nicotiana and unlocking enzymatic routes to pyridine alkaloids.
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May 2026
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B23-Circular Dichroism
|
Diamond Proposal Number(s):
[35790, 40009]
Open Access
Abstract: The formation of chiral structures from achiral building blocks, and the propagation of chirality across length-scales in soft matter are still poorly understood phenomena. Here, we have studied a system revealing an exceptional diversity of spontaneously chiral phases formed by achiral mesogenic dimers linked by spacers with an odd number of atoms. Depending on terminal chain length and temperature, these compounds form a well-known heliconical nematic (NTB) phase and distinct helical smectic phases - ranging from the nanoscale-pitch SmCTB–SH, through the SmCTB–DH phase with ~ 50 nm periodicity, to the newly identified SmCTB–C phase featuring a micron-scale helix. In the SmCTB–C phase heliconical order is preserved even though the interlayer molecular intercalations strongly suppress the azimuthal rotation of the director. Resonant soft X-ray scattering (RSoXS) measurements were performed for the first time across an entire homologous series. Results confirmed the double-helical structure of the SmCTB–DH phase in which a longer helix is superimposed on the short one. The intensity of the resonant signals revealed an anomaly: the non-monotonic temperature evolution is due to the transient passage of the structure from a four-layer helix, through a nearly perfect three-layer clock-like helix, before decoupling of the short and long helices at lower temperatures.
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May 2026
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I21-Resonant Inelastic X-ray Scattering (RIXS)
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Yujie
Yan
,
Ying
Chan
,
Xunyang
Hong
,
S. Lin Er
Chow
,
Zhaoyang
Luo
,
Yuehong
Li
,
Tianren
Wang
,
Yuetong
Wu
,
Izabela
Bialo
,
Nurul
Fitriyah
,
Saurav
Prakash
,
Xing
Gao
,
King Yau
Yip
,
Qiang
Gao
,
Xiaolin
Ren
,
Jaewon
Choi
,
Ganesha
Channagowdra
,
Jun
Okamoto
,
Xingjiang
Zhou
,
Zhihai
Zhu
,
Liang
Si
,
Mirian
Garcia-Fernandez
,
Ke-Jin
Zhou
,
Hsiao-Yu
Huang
,
Di-Jing
Huang
,
Johan
Chang
,
Ariando
Ariando
,
Qisi
Wang
Diamond Proposal Number(s):
[30189]
Open Access
Abstract: The recent discovery of high-temperature superconductivity in hole-doped SmNiO2, exhibiting the record-high transition temperature Tc among infinite-layer (IL) nickelates, has opened a new avenue for exploring design principles of superconductivity. Experimentally determining the electronic structure and magnetic interactions in this new system is crucial to elucidating the mechanism behind the enhanced superconductivity. Here, we report a Ni L-edge resonant inelastic x-ray scattering (RIXS) study of superconducting Sm-based IL nickelate thin films Sm1−x−yEuxCayNiO2 (SECNO). Dispersive paramagnonic excitations are observed in both optimally and overdoped SECNO samples, supporting a spin-fluctuation-mediated pairing scenario. However, despite the two-fold enhancement of Tc in the Sm-based nickelates compared to their Pr-based counterparts, the effective exchange coupling strength is reduced by approximately 20%. This behavior contrasts with hole-doped cuprates, where magnetic interactions correlate positively with Tc, highlighting essential differences in their superconducting mechanisms.
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May 2026
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