E02-JEM ARM 300CF
|
Jichao
Zhang
,
Jiexin
Zhu
,
Liqun
Kang
,
Qing
Zhang
,
Longxiang
Liu
,
Fei
Guo
,
Kaiqi
Li
,
Jianrui
Feng
,
Lixue
Xia
,
Lei
Lv
,
Wei
Zong
,
Paul R.
Shearing
,
Dan J. L.
Brett
,
Ivan P.
Parkin
,
Xuedan
Song
,
Liqiang
Mai
,
Guanjie
He
Diamond Proposal Number(s):
[32058, 33118]
Open Access
Abstract: Electrochemical urea splitting provides a sustainable and environmentally benign route for facilitating energy conversion. Nonetheless, the sustained efficiency of urea splitting is impeded by a scarcity of active sites during extended operational periods. Herein, an atomic heterostructure engineering strategy is proposed to promote the generation of active species via synthesizing unique Ru–O4 coordinated single atom catalysts anchored on Ni hydroxide (Ru1–Ni(OH)2), with ultralow Ru loading mass of 40.6 μg cm−2 on the nickel foam for commercial feasibility. Leveraging in situ spectroscopic characterizations, the structure-performance relationship in low and high urea concentrations was investigated and exhibited extensive universality. The boosted generation of dynamic Ni3+ active sites ensures outstanding activity and prominent long-term durability tests in various practical scenarios, including 100 h Zn–urea–air battery operation, 100 h alkaline urine electrolysis, and over 400 h stable hydrogen production in membrane electrode assembly (MEA) system under industrial-level current density.
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Nov 2023
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I04-Macromolecular Crystallography
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George H.
Hutchins
,
Sebastian
Kiehstaller
,
Pascal
Poc
,
Abigail H.
Lewis
,
Jisun
Oh
,
Raya
Sadighi
,
Nicholas M.
Pearce
,
Mohamed
Ibrahim
,
Ivana
Drienovská
,
Anouk M.
Rijs
,
Saskia
Neubacher
,
Sven
Hennig
,
Tom N.
Grossmann
Diamond Proposal Number(s):
[25413]
Open Access
Abstract: Proteins are essential biomolecules and central to biotechnological applications. In many cases, assembly into higher-order structures is a prerequisite for protein function. Under conditions relevant for applications, protein integrity is often challenged, resulting in disassembly, aggregation, and loss of function. The stabilization of quaternary structure has proven challenging, particularly for trimeric and higher-order complexes, given the complexity of involved inter- and intramolecular interaction networks. Here, we describe the chemical bicyclization of homotrimeric protein complexes, thereby increasing protein resistance toward thermal and chemical stress. This approach involves the structure-based selection of cross-linking sites, their variation to cysteine, and a subsequent reaction with a triselectrophilic agent to form a protein assembly with bicyclic topology. Besides overall increased stability, we observe resistance toward aggregation and greatly prolonged shelf life. This bicyclization strategy gives rise to unprecedented protein chain topologies and can enable new biotechnological and biomedical applications.
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Nov 2023
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B18-Core EXAFS
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Diamond Proposal Number(s):
[15859]
Abstract: Metabolisms that evolved in the Archaean era (4.0–2.5 billion years ago) preferentially selected iron, manganese and molybdenum to form metalloproteins, whereas the majority of zinc-, copper- and vanadium-binding proteins emerged much later. The initial preference for these elements is commonly interpreted to reflect their availability in anoxic seawater, with free sulfide proposed as a key influence. While sulfidic waters reduce the availability of zinc and copper, they also remove molybdenum and leave behind vanadium. Furthermore, current geochemical data reflect predominantly ferruginous (Fe2+-rich), rather than sulfidic, conditions. Consistent with this, recent sedimentological work has uncovered abundant iron silicate minerals in Archaean rocks. Here we quantify metal partitioning during the formation and subsequent diagenesis of an Fe(II) silicate mineral, a precursor to crystalline greenalite, in both seawater and hot hydrothermal fluids. Our data show that Fe(II) silicates could have precipitated rapidly in Archaean hydrothermal plumes, severely attenuating hydrothermal delivery of key nutrients, in particular copper, zinc and vanadium. These results provide a mechanistic explanation for metal availability patterns in Archaean oceans that is consistent with temporal patterns of metal utilization predicted from protein structures and comparative genomics. Further, our data suggest natural greenalite may provide an archive of metal availability in deep time.
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Nov 2023
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[29072]
Open Access
Abstract: Synthetic cells, like their biological counterparts, require internal compartments with distinct chemical and physical properties where different functionalities can be localized. Inspired by membrane-less compartmentalization in biological cells, here, we demonstrate how microphase separation can be used to engineer heterogeneous cell-like architectures with programmable morphology and compartment-targeted activity. The synthetic cells self-assemble from amphiphilic DNA nanostructures, producing core-shell condensates due to size-induced de-mixing. Lipid deposition and phase-selective etching are then used to generate a porous pseudo-membrane, a cytoplasm analog, and membrane-less organelles. The synthetic cells can sustain RNA synthesis via in vitro transcription, leading to cytoplasm and pseudo-membrane expansion caused by an accumulation of the transcript. Our approach exemplifies how architectural and functional complexity can emerge from a limited number of distinct building blocks, if molecular-scale programmability, emergent biophysical phenomena, and biochemical activity are coupled to mimic those observed in live cells.
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Nov 2023
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I04-1-Macromolecular Crystallography (fixed wavelength)
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Diamond Proposal Number(s):
[24948, 18598]
Open Access
Abstract: Bacteria and yeasts grow on biomass polysaccharides by expressing and excreting a complex array of glycoside hydrolase (GH) enzymes. Identification and annotation of such GH pools, which are valuable commodities for sustainable energy and chemistries, by conventional means (genomics, proteomics) are complicated, as primary sequence or secondary structure alignment with known active enzymes is not always predictive for new ones. Here we report a “low-tech”, easy-to-use, and sensitive multiplexing activity-based protein-profiling platform to characterize the xyloglucan-degrading GH system excreted by the soil saprophyte, Cellvibrio japonicus, when grown on xyloglucan. A suite of activity-based probes bearing orthogonal fluorophores allows for the visualization of accessory exo-acting glycosidases, which are then identified using biotin-bearing probes. Substrate specificity of xyloglucanases is directly revealed by imbuing xyloglucan structural elements into bespoke activity-based probes. Our ABPP platform provides a highly useful tool to dissect xyloglucan-degrading systems from various sources and to rapidly select potentially useful ones. The observed specificity of the probes moreover bodes well for the study of other biomass polysaccharide-degrading systems, by modeling probe structures to those of desired substrates.
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Nov 2023
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I16-Materials and Magnetism
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L.
Shen
,
V.
Esposito
,
N. G.
Burdet
,
M.
Zhu
,
A. N.
Petsch
,
T. P.
Croft
,
S. P.
Collins
,
Z.
Ren
,
F.
Westermeier
,
M.
Sprung
,
S. M.
Hayden
,
J. J.
Turner
,
E.
Blackburn
Diamond Proposal Number(s):
[11098]
Open Access
Abstract: In the cuprate superconductors, the spatial coherence of the charge density wave (CDW) state grows below a temperature
T
CDW
, the origin of which is debated. Using x-ray photon correlation spectroscopy, we have studied the temporal atomic relaxation dynamics in
La
1.88
Sr
0.12
CuO
4
to shed light on this question. Cooling within an emergent structurally distorted phase, which favors the CDW modulation in symmetry and develops in two stages between 180 and 120 K, we observe a crossover from cooperativelike to incoherentlike relaxation dynamics at
T
CDW
=
75
(
10
)
K
. We argue that, if the CDW is hosted by this distortion, the concomitant relaxational crossover and enhancement of CDW spatial coherence supports the interplay between relaxational atomic fluctuations and CDWs in materials of this class on quasistatic times cales.
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Nov 2023
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B21-High Throughput SAXS
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Diamond Proposal Number(s):
[20221]
Open Access
Abstract: Small-angle X-ray and neutron scattering (SAXS/SANS) provide valuable insights into the structure and dynamics of biomolecules in solution, complementing a wide range of structural techniques, including molecular dynamics simulations. As contrast-based methods, they are sensitive not only to structural properties but also to solvent–solute interactions. Their use in molecular dynamics simulations requires a forward model that should be as fast and accurate as possible. In this work, we demonstrate the feasibility of calculating SAXS and SANS intensities using a coarse-grained representation consisting of one bead per amino acid and three beads per nucleic acid, with form factors that can be corrected on the fly to account for solvation effects at no additional computational cost. By coupling this forward model with molecular dynamics simulations restrained with SAS data, it is possible to determine conformational ensembles or refine the structure and dynamics of proteins and nucleic acids in agreement with the experimental results. To assess the robustness of this approach, we applied it to gelsolin, for which we acquired SAXS data on its closed state, and to a UP1-microRNA complex, for which we used previously collected measurements. Our hybrid-resolution small-angle scattering (hySAS) implementation, being distributed in PLUMED, can be used with atomistic and coarse-grained simulations using diverse restraining strategies.
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Nov 2023
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I05-ARPES
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Masafumi
Horio
,
Filomena
Forte
,
Denys
Sutter
,
Minjae
Kim
,
Claudia G.
Fatuzzo
,
Christian E.
Matt
,
Simon
Moser
,
Tetsuya
Wada
,
Veronica
Granata
,
Rosalba
Fittipaldi
,
Yasmine
Sassa
,
Gianmarco
Gatti
,
Henrik M.
Ronnow
,
Moritz
Hoesch
,
Timur K.
Kim
,
Chris
Jozwiak
,
Aaron
Bostwick
,
Eli
Rotenberg
,
Iwao
Matsuda
,
Antoine
Georges
,
Giorgio
Sangiovanni
,
Antonio
Vecchione
,
Mario
Cuoco
,
Johan
Chang
Diamond Proposal Number(s):
[10550]
Open Access
Abstract: Doped Mott insulators are the starting point for interesting physics such as high temperature superconductivity and quantum spin liquids. For multi-band Mott insulators, orbital selective ground states have been envisioned. However, orbital selective metals and Mott insulators have been difficult to realize experimentally. Here we demonstrate by photoemission spectroscopy how Ca2RuO4, upon alkali-metal surface doping, develops a single-band metal skin. Our dynamical mean field theory calculations reveal that homogeneous electron doping of Ca2RuO4 results in a multi-band metal. All together, our results provide evidence for an orbital-selective Mott insulator breakdown, which is unachievable via simple electron doping. Supported by a cluster model and cluster perturbation theory calculations, we demonstrate a type of skin metal-insulator transition induced by surface dopants that orbital-selectively hybridize with the bulk Mott state and in turn produce coherent in-gap states.
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Nov 2023
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[14892, 15525, 24680]
Abstract: The kinetics of heterogeneous polymerization is determined directly using small-angle X-ray scattering (SAXS). This important advance is exemplified for the synthesis of sterically-stabilized diblock copolymer nanoparticles by reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of benzyl methacrylate (BzMA) in mineral oil at 90 °C. The principle of mass balance is invoked to derive a series of equations for the analysis of the resulting time-resolved SAXS patterns. Importantly, there is a continuous change in the X-ray scattering length density for the various components within the reaction mixture. This enables the volume fraction of unreacted BzMA monomer to be calculated at any given time point, which enables the polymerization kinetics to be monitored in situ directly without relying on supplementary characterization techniques. Moreover, SAXS enables the local concentration of both monomer and solvent within the growing swollen nanoparticles to be determined during the polymerization. The analysis reveals that the instantaneous rate of BzMA polymerization is proportional to the local monomer concentration within the nanoparticles. In principle, this powerful new time-resolved SAXS approach should be applicable to other heterogeneous polymerization formulations.
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Nov 2023
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B16-Test Beamline
Optics
|
Diamond Proposal Number(s):
[26501, 31201]
Open Access
Abstract: For advanced X-ray sources such as synchrotron radiation facilities and X-ray free electron lasers, a smooth, structure-free beam on the far-field plane is usually strongly desired. The formation of the fine structures in far-field images downstream from imperfect optics must be understood. Although numerous studies have discussed the impacts on focused beams, there are still few quantitative theories for the impacts on beams in the far field. This article is an advance on our previous work, which discussed the uniformity of the intensity distribution in the far field. Here, a new theoretical approach is presented. It not only eases the assumptions needed to relate the fine structures to the wavefront curvature, but it also provides a quantitative estimation of the impacts of optical errors. The theoretical result is also verified by X-ray experiments.
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Nov 2023
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