I07-Surface & interface diffraction
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Diamond Proposal Number(s):
[26630]
Open Access
Abstract: Organic solar cells (OSCs), also known as organic photovoltaics (OPVs), are an emerging solar cell technology composed of carbon-based, organic molecules, which convert energy from the sun into electricity. Key for their performance is the microstructure of the light-absorbing organic bulk heterojunction. To study this, organic solar films composed of both fullerene C60 as electron acceptor and different mole percentages of di-[4-(N,N-di-p-tolyl-amino)-phenyl]-cyclohexane (TAPC) as electron donor were evaporated in vacuum in different mixing ratios (5, 50 and 95 mol%) on an ITO-coated glass substrate held at room temperature and at 110 °C. The microstructure of the C60: TAPC heterojunction was studied by grazing incidence wide angle X-ray scattering to understand the effect of substrate heating. By increasing the substrate temperature from ambient to 110 °C, it was found that no significant change was observed in the crystal size for the C60: TAPC concentrations investigated in this study. In addition to the variation done in the substrate temperature, the variation of the mole percent of the donor (TAPC) was studied to conclude the effect of both the substrate temperature and the donor concentration on the microstructure of the OSC films. Bragg peaks were attributed to C60 in the pure C60 sample and in the blend with low donor mole percentage (5%), but the C60 peaks became nondiscernible when the donor mole percentage was increased to 50% and above, showing that TAPC interrupted the formation of C60 crystals.
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Apr 2021
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Krios II-Titan Krios II at Diamond
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Yasunori
Watanabe
,
Luiza
Mendonca
,
Elizabeth R.
Allen
,
Andrew
Howe
,
Mercede
Lee
,
Joel D.
Allen
,
Himanshi
Chawla
,
David
Pulido
,
Francesca
Donnellan
,
Hannah
Davies
,
Marta
Ulaszewska
,
Sandra
Belij-Rammerstorfer
,
Susan
Morris
,
Anna-Sophia
Krebs
,
Wanwisa
Dejnirattisai
,
Juthathip
Mongkolsapaya
,
Piyada
Supasa
,
Gavin R.
Screaton
,
Catherine M.
Green
,
Teresa
Lambe
,
Peijun
Zhang
,
Sarah C.
Gilbert
,
Max
Crispin
Diamond Proposal Number(s):
[18477, 21005, 21004]
Abstract: Vaccine development against the SARS-CoV-2 virus focuses on the principal target of the neutralizing immune response, the spike (S) glycoprotein. Adenovirus-vectored vaccines offer an effective platform for the delivery of viral antigen, but it is important for the generation of neutralizing antibodies that they produce appropriately processed and assembled viral antigen that mimics that observed on the SARS-CoV-2 virus. Here, we describe the structure, conformation, and glycosylation of the S protein derived from the adenovirus-vectored ChAdOx1 nCoV-19/AZD1222 vaccine. We demonstrate native-like post-translational processing and assembly, and reveal the expression of S proteins on the surface of cells adopting the trimeric prefusion conformation. The data presented here confirm the use of ChAdOx1 adenovirus vectors as a leading platform technology for SARS-CoV-2 vaccines.
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Apr 2021
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Abstract: Despite their ubiquitous usage and increasing societal dependence on Li-ion batteries, there remains a lack of detailed empirical evidence of Li intercalation/deintercalation into graphite even though this process dictates the performance, longevity, and safety of the system. Here, we report direct detection and dissociation of specific crystallographic phases in the lithiated graphite, which form through a stepwise staging process. Using operando measurements, LiC18, LiC12, and LiC6 phases are observed via distinct low-frequency Raman features, which are the result of displacement of the graphite lattice by induced local strain. Density functional theory calculations confirm the nature of the Raman-active vibrational modes, to the layer breathing modes (LBMs) of the lithiated graphite. The new findings indicate graphene-like characteristics in the lithiated graphite under the deep charged condition due to the imposed strain by the inserted Li. Moreover, our approach also provides a simple experimental tool to measure induced strain in the graphite structure under full intercalation conditions.
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Apr 2021
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Theoretical Physics
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Frank M. F.
De Groot
,
Hebatalla
Elnaggar
,
Federica
Frati
,
Ru-Pan
Wang
,
Mario U.
Delgado-Jaime
,
Michel
Van Veenendaal
,
Javier
Fernandez-Rodriguez
,
Maurits W.
Haverkort
,
Robert J.
Green
,
Gerrit
Van Der Laan
,
Yaroslav
Kvashnin
,
Atsushi
Hariki
,
Hidekazu
Ikeno
,
Harry
Ramanantoanina
,
Claude
Daul
,
Bernard
Delley
,
Michael
Odelius
,
Marcus
Lundberg
,
Oliver
Kuhn
,
Sergey I.
Bokarev
,
Eric
Shirley
,
John
Vinson
,
Keith
Gilmore
,
Mauro
Stener
,
Giovanna
Fronzoni
,
Piero
Decleva
,
Peter
Kruger
,
Marius
Retegan
,
Yves
Joly
,
Christian
Vorwerk
,
Claudia
Draxl
,
John
Rehr
,
Arata
Tanaka
Open Access
Abstract: This review provides an overview of the different methods and computer codes that are used to interpret 2p x-ray absorption spectra of 3d transition metal ions. We first introduce the basic parameters and give an overview of the methods used. We start with the semi-empirical multiplet codes and compare the different codes that are available. A special chapter is devoted to the user friendly interfaces that have been written on the basis of these codes. Next we discuss the first principle codes based on band structure, including a chapter on Density Functional theory based approaches. We also give an overview of the first-principle multiplet codes that start from a cluster calculation and we discuss the wavefunction based methods, including multi-reference methods. We end the review with a discussion of the link between theory and experiment and discuss the open issues in the spectral analysis.
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Apr 2021
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I05-ARPES
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X.
Lou
,
T. l.
Yu
,
Y. h.
Song
,
C. h. P.
Wen
,
W. z.
Wei
,
A.
Leithe-Jasper
,
Z. f.
Ding
,
L.
Shu
,
S.
Kirchner
,
H. C.
Xu
,
R.
Peng
,
D. L.
Feng
Diamond Proposal Number(s):
[22518]
Abstract: CeOs
4
Sb
12
(COS) and
PrOs
4
Sb
12
(POS) are two representative compounds that provide the ideal vantage point to systematically study the physics of multi-
f
-electron systems. COS with Ce
4
f
1
, and POS with Pr
4
f
2
configurations show distinct properties of Kondo insulating and heavy fermion superconductivity, respectively. We unveiled the underlying microscopic origin by angle-resolved photoemission spectroscopy studies. Their eV-scale band structure matches well, representing the common characters of conduction electrons in
R
Os
4
Sb
12
systems (
R
=
rare
earth
). However,
f
electrons interact differently with conduction electrons in COS and POS. Strong hybridization between conduction electrons and
f
electrons is observed in COS with band dependent hybridization gaps, and the development of a Kondo insulating state is directly revealed. Although the ground state of POS is a singlet, finite but incoherent hybridization exists, which can be explained by the Kondo scattering with the thermally excited triplet crystalline electric field state. Our results help us to understand the intriguing properties in COS and POS, and provide a clean demonstration of the microscopic differences in heavy fermion systems with
4
f
1
and
4
f
2
configurations.
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Apr 2021
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B18-Core EXAFS
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Diamond Proposal Number(s):
[15151]
Abstract: Hydrothermal degreening and ageing procedures were applied to a tri-metal (Pt-Pd-Rh) fully formulated lean NOX Trap catalyst to evaluate the effects of thermal stress on the performances and structural properties. X-ray absorption fine structure (XAFS) analysis revealed that the average size of the platinum particles was the same after degreening and ageing treatments. The formation of a new phase of alloyed Pt-Pd was observed to increase with the thermal load. The size of the ceria particles also increased after the ageing treatment. NOX storage capacity experiments revealed a substantial decrease of the concentration of active NOX storage sites which correlated with both ageing and degreening protocols. The performances of the treated catalyst were evaluated through spatially resolved (SpaciMS) lean-rich cycles. During the lean phase, the impact of the decrease in storage sites was significant on the aged sample, where an enlargement of the area required to achieve full storage was observed. On the other hand, the regeneration functionalities did not appear to be particularly affected by ageing. Rather, the aged sample showed a decrease of oxygen storage capacity (OSC), which promoted a lower reductant consumption and therefore a quicker and more efficient reduction process. On the other hand, the different distributions of adsorbed species by the end of the lean phase produced greater spread presence of NH3 and NOX slip along the channels of the aged sample during the reduction.
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Apr 2021
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Zahraa S.
Al-Taie
,
Joseph M.
Anderson
,
Laura
Bischoff
,
Jeppe
Christensen
,
Simon J.
Coles
,
Richard
Froom
,
Mari E.
Gibbard
,
Leigh F.
Jones
,
F. F. J.
De Kleijne
,
Patrick J.
Murphy
,
Emma C.
Thompson
Abstract: We report the preparation of a range of N-protected amino acid derived guanidine organocatalysts and their application to the Michael addition of 2-hydroxy-1,4-napthoquinone to β-nitrostyrene, achieving a maximum ee of 26%. Whilst these catalysts gave poor ees, the structural variation together with the X-ray crystallographic study of the intra- and intermolecular hydrogen bonding reported suggest that the C2-symmetric catalyst are lead compounds for the further development of this methodology.
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Apr 2021
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[19880]
Open Access
Abstract: ADAMTS13 is a plasma metalloprotease that is essential for the regulation of von Willebrand factor (VWF) function, mediator of platelet recruitment to sites of blood vessel damage. ADAMTS13 function is dynamically regulated by structural changes induced by VWF binding that convert it from a latent to active conformation. ADAMTS13 global latency is manifest by the interaction of its C-terminal CUB1-2 domains with its central Spacer domain. We resolved the crystal structure of the ADAMTS13 CUB1-2 domains revealing a previously unreported configuration for the tandem CUB domains. Docking simulations between the CUB1-2 domains with the Spacer domain in combination with enzyme kinetic functional characterization of ADAMTS13 CUB domain mutants enabled the mapping of the CUB1-2 domain site that binds the Spacer domain. Together, these data reveal the molecular basis of the ADAMTS13 Spacer-CUB interaction and the control of ADAMTS13 global latency.
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Apr 2021
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Sebastian
Gunther
,
Patrick Y. A.
Reinke
,
Yaiza
Fernández-García
,
Julia
Lieske
,
Thomas J.
Lane
,
Helen M.
Ginn
,
Faisal H. M.
Koua
,
Christiane
Ehrt
,
Wiebke
Ewert
,
Dominik
Oberthuer
,
Oleksandr
Yefanov
,
Susanne
Meier
,
Kristina
Lorenzen
,
Boris
Krichel
,
Janine-Denise
Kopicki
,
Luca
Gelisio
,
Wolfgang
Brehm
,
Ilona
Dunkel
,
Brandon
Seychell
,
Henry
Gieseler
,
Brenna
Norton-Baker
,
Beatriz
Escudero-Pérez
,
Martin
Domaracky
,
Sofiane
Saouane
,
Alexandra
Tolstikova
,
Thomas A.
White
,
Anna
Hänle
,
Michael
Groessler
,
Holger
Fleckenstein
,
Fabian
Trost
,
Marina
Galchenkova
,
Yaroslav
Gevorkov
,
Chufeng
Li
,
Salah
Awel
,
Ariana
Peck
,
Miriam
Barthelmess
,
Frank
Schluenzen
,
Paulraj
Lourdu Xavier
,
Nadine
Werner
,
Hina
Andaleeb
,
Najeeb
Ullah
,
Sven
Falke
,
Vasundara
Srinivasan
,
Bruno Alves
França
,
Martin
Schwinzer
,
Hévila
Brognaro
,
Cromarte
Rogers
,
Diogo
Melo
,
Joanna J.
Zaitseva-Doyle
,
Juraj
Knoska
,
Gisel E.
Peña-Murillo
,
Aida Rahmani
Mashhour
,
Vincent
Hennicke
,
Pontus
Fischer
,
Johanna
Hakanpää
,
Jan
Meyer
,
Philip
Gribbon
,
Bernhard
Ellinger
,
Maria
Kuzikov
,
Markus
Wolf
,
Andrea R.
Beccari
,
Gleb
Bourenkov
,
David
Von Stetten
,
Guillaume
Pompidor
,
Isabel
Bento
,
Saravanan
Panneerselvam
,
Ivars
Karpics
,
Thomas R.
Schneider
,
Maria Marta
Garcia-Alai
,
Stephan
Niebling
,
Christian
Günther
,
Christina
Schmidt
,
Robin
Schubert
,
Huijong
Han
,
Juliane
Boger
,
Diana C. F.
Monteiro
,
Linlin
Zhang
,
Xinyuanyuan
Sun
,
Jonathan
Pletzer-Zelgert
,
Jan
Wollenhaupt
,
Christian G.
Feiler
,
Manfred S.
Weiss
,
Eike-Christian
Schulz
,
Pedram
Mehrabi
,
Katarina
Karničar
,
Aleksandra
Usenik
,
Jure
Loboda
,
Henning
Tidow
,
Ashwin
Chari
,
Rolf
Hilgenfeld
,
Charlotte
Uetrecht
,
Russell
Cox
,
Andrea
Zaliani
,
Tobias
Beck
,
Matthias
Rarey
,
Stephan
Günther
,
Dusan
Turk
,
Winfried
Hinrichs
,
Henry N.
Chapman
,
Arwen R.
Pearson
,
Christian
Betzel
,
Alke
Meents
Open Access
Abstract: The coronavirus disease (COVID-19) caused by SARS-CoV-2 is creating tremendous human suffering. To date, no effective drug is available to directly treat the disease. In a search for a drug against COVID-19, we have performed a high-throughput X-ray crystallographic screen of two repurposing drug libraries against the SARS-CoV-2 main protease (Mpro), which is essential for viral replication. In contrast to commonly applied X-ray fragment screening experiments with molecules of low complexity, our screen tested already approved drugs and drugs in clinical trials. From the three-dimensional protein structures, we identified 37 compounds that bind to Mpro. In subsequent cell-based viral reduction assays, one peptidomimetic and six non-peptidic compounds showed antiviral activity at non-toxic concentrations. We identified two allosteric binding sites representing attractive targets for drug development against SARS-CoV-2.
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Apr 2021
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B18-Core EXAFS
I20-Scanning-X-ray spectroscopy (XAS/XES)
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Abstract: Mixed metal oxides are important catalysts in industrial processes that transform bulk hydrocarbons into useful intermediates and products. The oxygen lattice is uniquely able to facilitate redox reactions by rapidly transporting reactive species between active sites. The bulk structure of the lattice governs the availability of electrons, the reactivity of oxygen, and hence the efficiency of catalytic processes. An in-depth understanding of catalyst structure and formation mechanisms is therefore key to the development of effective catalysts. The study of relatively simple oxides gives fundamental knowledge that cannot always be applied to the more complex mixed metal oxide systems that are patented and put into use industrially. The goal of this research is to apply fundamental techniques to complex, commercial catalysts, under industrially relevant conditions, and systematically make sense of the complexity. A range of characterisation techniques that probe different aspects of catalyst structure are used in this thesis during catalyst synthesis to follow (re)organisation pathways of mixed metal oxides and identify the different structures that form. Two mixed metal oxide systems were chosen for investigation: a Cu-spinel based hydrogenation catalyst and a Mo oxide selective oxidation catalyst. The structural transformations during different synthesis steps were analysed using X-ray Absorption Spectroscopy (XAS), X-ray Diffraction (XRD), Infrared (IR), and Raman spectroscopy. New insights into both catalyst systems are discussed and several approaches to catalyst characterisation on different length scales are demonstrated to deliver a holistic understanding of catalyst synthesis.
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Apr 2021
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