forthcoming articles

The following articles are a selection of those recently accepted for publication in IUCr journals.

IUCrJ
Accepted 24 July 2017

Single-particle cryo-EM using alignment by classification (ABC): the structure of Lumbricus terrestris hemoglobin

An efficient and fast pipeline is presented for obtaining near-atomic resolution structures from large single-particle cryo-EM datasets. The approach is virtually reference-free and therefore less prone to the perils of reference bias.

Accepted 19 July 2017

Charge Transport Properties of 4-(1,2,2-tri­phenyl­vinyl)­aniline salicylaldehyde hydrazone: Tight-Packing Induced Molecular `Hardening'

In our manuscript, taking 4-(1,2,2-triphenylvinyl)­aniline salicylaldehyde hydrazone (A) as an example, we computed and analyzed the relationship between molecular packing and charge-transport parameters, and furthermore, the conducting properties of A is also predicted in the framework of hopping models.

Accepted 18 July 2017

A closer look into close packing: pentacoordinated silicon in the high-pressure polymorph of danburite

High-pressure single-crystal X-ray diffraction study of danburite, CaB2Si2O8, has revealed that it is the first compound showing a step-wise transition of Si coordination from tetrahedral to octahedral through trigonal bipyramidal. Along the compression, Si2O7 groups of danburite first transform into chains of vertice-sharing SiO5 trigonal bipyramids (danburite-II) and later into chains of edge-sharing SiO6 octahedra (danburite-III).

Accepted 13 July 2017

Real-time powder diffraction studies of energy materials under non-equilibrium conditions

This topical review presents developments in the analysis of functional energy materials using real-time operando X-ray and neutron powder diffraction of non-equilibrium systems. Examples in the areas of porous framework materials and rechargeable battery electrodes are used to highlight improvements in structural detail gained for guest–host systems through advances in instrumentation and experimental approach.

Accepted 10 July 2017

Background modelling of diffraction data in the presence of ice rings

An algorithm for modelling the background of X-ray diffraction images in the presence of ice rings is presented.

Accepted 10 July 2017

Bond softness sensitive bond-valence parameters for crystal structure plausibility tests

Consistent sets of bond-valence parameters comprising 706 types of cation–anion pairs are derived and evaluated with respect to the impact of variable bond softness b, the first coordination shell convention and an unbiased determination of the cation coordination number.

Accepted 26 June 2017

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

The optimal XFEL pulse duration for single-particle imaging of small proteins is narrowed down to the 3–9 fs range, using start-to-end simulations of a single-particle imaging experiment at the European XFEL.

Accepted 12 June 2017

Progress in small-angle scattering from biological solutions at high-brilliance synchrotrons

Small-angle X-ray scattering (SAXS) is an established technique that provides low-resolution structural information on macromolecular solutions. This review illustrates the latest progress in the field, highlighting analytical methods for flexible and evolving systems, progress in time-resolved SAXS and developments in archiving and validation.

Accepted 8 June 2017

Experimental phase determination with selenome­thionine or mercury-derivatization in serial femtosecond crystallography

High-energy X-rays are essential for de novo structure determination with strong anomalous scattering from selenium or mercury. Single-wavelength anomalous diffraction phasing using selenomethionine-derivatization and mercury-soaking techniques has been successfully applied to serial femtosecond crystallography with 13.0 keV or 12.6 keV X-rays produced at SACLA.

Accepted 7 June 2017

A distance geometry-based description and validation of protein main-chain conformation

The conformation of the protein main chain is described in a novel three-dimensional space derived from the interatomic distances. This allows the local and overall validation of protein backbone geometry and the detection of residues that are strained for reasons of their function.

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Journal logoActa Crystallographica Section A
Acta Crystallographica
Section A
FOUNDATIONS AND ADVANCES

Accepted 19 June 2017

Accelerated scattering of convex polyhedra

The formulas for minn and maxn names in the classes of convex n-acra, as well as asymptotic relationships (as n → ∞) between them, are found. These explain the distribution of [minn, maxn] ranges on the real line.

Accepted 15 June 2017

Close-packed structure dynamics with finite-range interaction: computational mechanics with individual layer interaction

This is the second contribution in a series of papers dealing with dynamical models in equilibrium theories of polytypism. Instead of using an Ising model over spins defined by the Hägg coding, a Hamiltonian considering direct interaction between the close-packed layers is assumed. The results of the phase diagram and the appearance of disorder are compared with the previous analysis using the Ising model. Computational mechanics is the framework under which the analysis is performed.

Accepted 15 May 2017

Mathematical aspects of molecular replacement. IV. Measure-theoretic decompositions of motion spaces


Accepted 8 May 2017

The wavevector substar group in reciprocal-lattice space and its representation

This paper establishes a new conception of the wavevector substar group and its representation.
Journal logoActa Crystallographica Section B
Acta Crystallographica
Section B
STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS

Accepted 21 July 2017

Multidimensional structural variation in the cyano­trichite family of merotypes: camerolaite-3b-F-1

This is the first refined example of a cyano­trichite-group mineral in which long-range order of interlayer anions produces a superstructure.

Accepted 28 June 2017

Approaches to crystal structure landscape exploration

Three approaches to the exploration of the crystal structure landscape are outlined. These are crystal structure prediction, non-ambient crystallography and charge density analysis.

Accepted 27 June 2017

Crystal chemistry and the role of ionic radius in rare earth tetrasilicates: Ba2RE2Si4O12F2 (RE = Er3+-Lu3+) and Ba2RE2Si4O13 (RE = La3+-Ho3+)

Multiple structure types were found in a systematic study of barium rare earth tetrasilicates. The ionic radius of the rare earth element and the presence of fluorine in the crystal structures direct both the phase stability and the structural dimensionality.

Accepted 19 June 2017

A note to the Distortion theorem


Accepted 19 June 2017

The index of dispersion as a metric of quanta – unravelling the Fano factor

The need for high-quality assessments of data motivates appreciation of shot noise as a data resource. The index of dispersion is a critical but often overlooked metric in this regard. When properly understood and carefully used it reveals the energies of quanta, in both monochromatic and polychromatic situations. To accomplish this, and in due course its wider application, its conceptual origins and quantitative and physical bounds are identified. Situations are examined that involve large numbers of quanta, but in which individual quanta are below measurement noise threshold. Practical applications are extremely diverse, so relevant considerations and how to use the metric are shown in broad contexts.

Accepted 9 June 2017

Effect of cationic substitution on the double well hydrogen bond potential in (K1-x(NH4)x)3H(SO4)2 proton conductors: A Single Crystal Neutron Diffraction Study

Single crystal neutron diffraction was performed on (K1-x(NH4)x)3H(SO4)2 in order to get the exact hydrogen bonding network, a correlation between the kinetics of superprotonic phase transition in the crystals and hydrogen bond strength is described.

Accepted 9 June 2017

Experimental observation of charge-shift bond in fluorite CaF2

F⋯F interactions in fluorite have properties associated with the recently recognized type of interaction referred to as `charge-shift' bonding. This finding is supported by the topology of the electron localization function and the analysis of quantum theory of atoms in molecules and crystals. These interactions are attractive in character, which is additionally indicated by the topology of non-covalent interactions based on the reduced density gradient.

Accepted 7 June 2017

Nanoscale symmetry fluctuations in ferroelectric barium titanate, BaTiO3

The crystal symmetry of ferroelectric BaTiO3 is determined by scanning convergent-beam electron diffraction. The results show inhomogeneous symmetry with nanometre-sized regions of almost perfect symmetry interspersed in regions of lower symmetry.

Accepted 7 June 2017

Solvent exchange in a metal–organic framework single crystal monitored by dynamic in situ X-ray diffraction

Dynamic in situ single crystal X-ray diffraction revealed unique and important information about the structural reorganization that occurs upon guest exchange in a cobalt-based metal organic framework.

Accepted 6 June 2017

Exploring charge density analysis in crystals at high pressure: data collection, data analysis and advanced modelling

This paper reports on the determination of charge density distributions from crystals compressed at high pressure. Although much less accurate than traditional charge density analysis, these studies provide valuable information because the electronic states of molecules confined in highly condensed space are not easily predictable by theory and therefore experimental validation is a must.

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Journal logoActa Crystallographica Section C
Acta Crystallographica
Section C
STRUCTURAL CHEMISTRY

Accepted 24 July 2017

Syntheses, structures and characterization of two new isomorphous coordination polymers based on 2-[(1H-imidazol-1-yl)meth­yl]-6-methyl-1H-benz­imidazole and benzene-1,4-di­carboxyl­ate

Two new isostructural coordination polymers based on 2-[(1H-imidazol-1-yl)meth­yl]-6-methyl-1H-benzimidazole (immbb) and benzene-1,4-di­carboxyl­ate have been prepared and structurally characterized. In the polymers, CoII or NiII ions are linked by bridging benzene-1,4-di­carboxyl­ate ligands to generate a one-dimensional chain, with immb ligands pendant on opposite sides of the main chain.

Accepted 24 July 2017

A phase transition caught in mid-course: independent and concomitant analyses of the monoclinic and triclinic structures of (nBu4N)[Co(orotate)2(bipy)]·3H2O

Repeated cycling through a reversible order–disorder phase transition in a crystal of a cobalt orotate complex produces an arrested transformation, leaving the sample with both triclinic and monoclinic domains. Independent determinations of the two structures were carried out from single-phase samples and the partial transition permitted simultaneous structure determination of the two phases at a temperature at which one of them is not expected to exist independently.

Accepted 21 July 2017

Computational, 1H NMR, and X-ray structural studies on 1-aryl­urazole tetra­zane dimers

ortho-Substituted 1-aryl­urazole radicals favor the formation of tetra­zane dimers rather than existing predominantly as independent free radicals like many other urazole radicals. The X-ray crystal structure of one of these dimers agreed well with a computational model and readily explained unusual shielding effects observed for some signals in the 1H NMR spectrum.

Accepted 21 July 2017

Intricacies of ligand coordination in tri­carbonylchromium(0) complexes with ortho- and para-fluoro­biphenyls

Solid-state geometries of [(η6-C6H5)(2-F-C6H4)]Cr(CO)3 and [(η6-C6H5)(4-F-C6H4)]Cr(CO)3 indicate exclusive coordination of the metal center to the more electron-rich arene ring. Unlike the structures of the free ligands, the chromium complexes exhibit no crystallographic symmetry and no positional disorder.

Accepted 3 July 2017

Synthesis and structure of a single-stranded dihelicate of vanadium(IV) involving a multi-ring nitro­gen heterocyclic ligand

A vanadium complex of a new redox-active bis-bidentate nitro­genous heterocyclic ligand, viz. 3,3′-bis­(pyridin-2-yl)-[1,1′]bi[imidazo[1,5-a]pyridin­yl], adopts a single-stranded helical structure and the ligand twists and bends in response to the stereoelectronic demand of the central metal ion. The metal centres in the complex are non-equivalent, each having a distorted octa­hedral geometry, with a V⋯V separation of 5.827 (2) Å. The structure also displays anion–π noncovalent inter­actions and arene C—H⋯anion nonclassical hydrogen bonds that play dominant roles in shaping the extended structure of the mol­ecule in the solid state.

Accepted 19 June 2017

Synthesis and characterization of (cryptand-222)potassium (2-methyl­imidazolato)(meso-tetra­phenyl­porphinato)ferrate(II)–2-methyl­imidazole–tetra­hydro­furan (1/1/2)

A salt of a (cryptand)potassium cation and a complex anion is described in which the central FeII atom is five-coordinated by an imidazolyl-substituted porphyrin and an imidazolate ligand.
Journal logoActa Crystallographica Section D
Acta Crystallographica
Section D
STRUCTURAL BIOLOGY

Accepted 25 July 2017

Designing better diffracting crystals of biotin carboxyl carrier protein from Pyrococcus horikoshii by a mutation based on crystal-packing propensity of amino acids

For improving the efficiency of protein crystallization, we devised an alternative approach using a mutation of surface residues, based on the results of statistical analysis of the crystal-packing propensity of amino acids. A systematic crystallization experiment validated the results of statistical analysis.

Accepted 20 July 2017

Crystal structures of methyltransferase and helicase from the ZIKA 1947 MR766 Uganda strain

We report high-resolution structures of the ZIKA virus (strain MR766) methyltransferase and helicase proteins.

Accepted 18 July 2017

The structure of the Pfp1 protease from a hyperthermophilic archaeon, Thermococcus thioreducens, in two crystal forms

The structure of the Pfp1 intracellular protease from Thermococcus thioreducens was solved in two crystal forms, one showing it to be a hexamer, and the other a dodecamer. Subunits are disulfide-linked in pairs and the very closely juxtaposed catalytic triads are formed across an interface with amino acids contributed by two separate subunits.

Accepted 12 July 2017

Protein structure determination by electron diffraction using a single three-dimensional nanocrystal

A single three-dimensional protein nanocrystal was used for structure determination using electron diffraction. Data were acquired using the rotation method with a Timepix hybrid pixel detector for low-dose data acquisition.

Accepted 5 July 2017

Structural basis for the regulation of chemotaxis by MapZ in the presence of c-di-GMP

The structure of CheR1 in complex with c-di-GMP-bound MapZ is reported and the complex biochemical process which involves CheR1, MapZ, SAH/SAM and c-di-GMP is revealed.

Accepted 3 July 2017

Binding of hydroxycitrate to human ATP-citrate lyase

Hydroxycitrate was co-crystallized with the amino-terminal portion of human ATP-citrate lyase in order to learn how this competitive inhibitor binds. Crystals diffracting to high resolution were obtained by adding cleavage sites in the protein to remove a disordered linker. This strategy could be useful for other proteins that do not crystallize well.

Accepted 3 July 2017

Model validation: local diagnosis, correction, and when to quit

An overview of current crystallographic model validation of protein and RNA, both foundations and criteria, at all resolution ranges is provided, together with advice on how to correct specific types of problems, and on when you should not try so hard that you are overfitting.

Accepted 1 July 2017

AUSPEX: a graphical tool for X-ray diffraction data analysis

AUSPEX is a new software tool for the statistical analysis of single-crystal X-ray diffraction data. It can be used to identify problems in the data resulting from the experiment itself, image processing, data scaling or conversion.

Accepted 29 June 2017

Crystal structure of the PEG-bound SH3 domain of myosin IB from Entamoeba histolytica reveals its mode of ligand recognition

An in-depth analysis of the PEG-bound C-terminal SH3 domain of myosin IB from E. histolytica has been performed, which reveals the mode of ligand recognition and will be helpful in the identification of probable binding partners of E. histolytica myosin IB.

Accepted 14 June 2017

An overview of comparative modelling and resources dedicated to large-scale modelling of genome sequences

This paper reviews the recent advances in computational template-based structural modelling and proposes the subclustering of protein domain superfamilies to guide the template-selection process.

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Journal logoActa Crystallographica Section E
Acta Crystallographica
Section E
CRYSTALLOGRAPHIC COMMUNICATIONS

Accepted 24 July 2017

Crystal structure of a 1,1,2,2-tetra­chloro­ethane-solvated hydrazinecarbo­thio­amide compound

The crystal structure of the title compound, which contains azomethine groups, is reported; its keto and enol tautomeric forms are investigated.

Accepted 21 July 2017

Crystal structure of ethyl (E)-2-cyano-3-(thio­phen-2-yl)acrylate: two conformers forming a discrete disorder

The mol­ecular structure of the title compound is characterized by a planarity that allows the formation of (010) sheets. However, the existence of two different conformations of the ethyl fragment introduces the occurrence of discrete disorder due to a mol­ecular overlay.

Accepted 21 July 2017

Pseudosymmetry and high Z′ structures: the case of rac-(2R,2′R,5′S)-2-methyl-5′-[(1R,2R,5S,5′S)-1,4,4,5′-tetra­methyl­dihydro-3′H-3,8-dioxa­spiro­[bi­cyclo­[3.2.1]octane-2,2′-furan]-5′-yl]-3,4,1′,2′,3′,4′-hexa­hydro-[2,2′-bi­furan]-5(2H)-one

The title compound crystallizes in the P\overline{1} space group, with four crystallographically independent mol­ecules.

Accepted 21 July 2017

A new solvate of epalerstat, a drug for diabetic neuropathy

The title compound, epalerstat acetone monosolvate, is isotypic with the previously reported tetra­hydro­furan solvate.

Accepted 11 July 2017

Synthesis and crystal structures of [Ph3PCH2PPh3]I2 di­chloro­methane disolvate and [Ph3PCH2PPh3](BI4)2

Reaction of BI3 with carbodi­phospho­rane, C(PPh3)2, gives a mixture of the dicationic compounds, [Ph3PCH2PPh3]I2·2CH2Cl2 and [Ph3PCH2PPh3](BI4)2. Solvents are the source of the protons at the ylidic C atom.

Accepted 5 July 2017

Crystal structures of the 2:2 complex of 1,1′-(1,2-phenyl­ene)bis­(3-(m-tolyl­urea) and tetra­butyl­ammonium chloride or bromide

The title compounds both comprise a tetra­butyl­ammonium cation, a halide anion and an ortho-phenyl­ene bis-urea mol­ecule. Each halide ion shows four N—H⋯X (X = Cl or Br) inter­actions with two urea receptor sites of different bis-urea moieties. A crystallographic inversion centre leads to the formation of a 2:2 arrangement of two halide anions and two bis-urea mol­ecules.
Journal logoActa Crystallographica Section F
Acta Crystallographica
Section F
STRUCTURAL BIOLOGY COMMUNICATIONS

Accepted 24 July 2017

In crystallo activity tests with latent apple tyrosinase and two mutants reveal the importance of the mutated sites for polyphenol oxidase activity

M. domestica polyphenol oxidase 1 (MdPPO1) was recombinantly expressed in its latent form (Lys1–Ser504) and successfully mutated at four different positions around the active centre which have been proposed to be decisive for the activity of the enzyme. The wild-type MdPPO1 and two of the mutants were successfully crystallized. In crystallo activity tests demonstrated the importance of these amino acids for the activity of the enzyme.

Accepted 19 July 2017

Filament-like DREP4 CIDE domain: characterization and preliminary X-ray crystallographic studies

The dynamic, filament-formation features of the DREP4 CIDE domain were characterized. The filament-like DREP4 CIDE domain was purified and crystallized in space group P212121, with unit-cell parameters a = 53.08, b = 76.58, c = 174.59 Å; the crystals diffracted to a resolution of 1.9 Å.

Accepted 18 July 2017

The quorum-quenching lactonase from Ali­cyclobacter acidoterrestris: purification, kinetic characterization, crystallization and crystallographic analysis

A lactonase from A. acidoterrestris named AaL has been isolated, purified, characterized and crystallized. The structure of AaL is expected to provide insights regarding its catalytic mechanism of lactone hydrolysis.

Accepted 15 July 2017

Crystal structure of the putative cytoplasmic protein STM0279 (Hcp2) from Salmonella typhimurium

The crystal structure of Hcp2 from S. typhimurium and its oligomeric state in solution are reported.

Accepted 5 July 2017

High-resolution structure of a Kazal-type serine protease inhibitor from the dengue vector Aedes aegypti

Its haematophagic habits and urban habitat make the mosquito Aedes aegypti an important vector of a number of human viruses. Here, the high-resolution crystal structure of AaTI, a noncanonical Kazal inhibitor from the saliva of A. aegypti, is presented, providing a molecular explanation for its inhibitory profile.

Accepted 2 July 2017

Expression and crystallographic studies of the D1D2 domains of C4.4A, a homologous protein to the urokinase receptor

The two amino-terminal LU domains of C4.4A were excised by limited proteolysis and were crystallized using the sitting-drop vapour-diffusion method. The crystals diffracted to 2.7 Å resolution, giving good-quality data.

Accepted 30 June 2017

1.12 Å resolution crystal structure of the catalytic domain of the plasmid-mediated colistin resistance determinant MCR-2

The crystal structure of the plasmid-mediated colistin resistance determinant MCR-2 has been determined at 1.12 Å resolution. This high-resolution structure highlights the molecular diversity of clinically relevant MCR proteins and provides an accurate starting model for further mechanistic, and in particular computational, studies.

Accepted 27 June 2017

Methylation, crystallization and SAD phasing of the Csu pilus CsuC–CsuE chaperone–adhesin subunit pre-assembly complex from Acinetobacter baumannii

Archaic Csu pili mediate the formation of A. baumannii biofilms on abiotic surfaces. To determine the structural basis for biofilm formation, native and selenomethionine-substituted pilus tip adhesin subunit CsuE complexed with the chaperone CsuC was produced in E. coli, purified and crystallized. Methylation of lysine residues was essential for crystallization of the complex. Initial phases were derived from selenomethionine-based single-wavelength anomalous dispersion.

Accepted 23 June 2017

Production, biophysical characterization and crystallization of Pseudomonas putida GraA and its complexes with GraT and the graTA operator

The antitoxin GraA from P. putida and its complexes with the toxin GraT and with the 33 bp operator of the graTA operon were crystallized.
Journal logoJournal of Applied Crystallography Journal of Applied
Crystallography

Accepted 24 July 2017

A tool for automatic recognition of [110] tilt grain boundaries in zinc blende-type crystals


Accepted 14 July 2017

A simple device for transferring an oriented crystal from a X-ray Laue diffractometer to a cutting machine


Accepted 7 July 2017

Nanoparticle Size Distribution Qu­antification: Results of a SAXS Inter-Laboratory Comparison

An extensive Round Robin experiment between SAXS laboratories has delivered a global uncertainty estimate for the measurands of a nanoparticle dispersion. Irrespective of the instrument pedigree, the distribution mean, width and volume fraction could be determined with an accuracy of 1%, 10%, and 10%, respectively.

Accepted 7 July 2017

Applications of dynamical theory of X-ray diffraction by perfect crystals to reciprocal space mapping

Dynamical theory of X-ray diffraction has been developed for spatially restricted beams. This approach allows one to calculate rocking curves as well as Reciprocal Space Maps for both the transmitted and reflected coherent wavefields.

Accepted 6 July 2017

Ewald: an extended wide-angle Laue diffractometer for the second target station of the Spallation Neutron Source

The design of a macromolecular neutron diffractometer for the second target station of the Spallation Neutron Source is detailed.

Accepted 23 June 2017

Electron backscatter diffraction study of orientation gradients at the grain boundaries of a polycrystalline steel sheet deformed along different loading paths

A statistical analysis of grain boundaries (GBs) in a polycrystalline steel sheet shows that a non-negligible fraction of the analyzed GB profiles can be described by an orientation profile with a constant slope near the GB and a constant value into the grain interior. Two parameters, based on the local orientation gradient assessed by electron backscatter diffraction, are proposed: boundary effective thickness and gradient average severity.

Accepted 18 June 2017

Bent Bragg–Laue monochromator for high-energy X-rays

A double-crystal monochromator composed of a meridionally bent Bragg crystal and a sagittally bent Laue crystal is proposed for bi-directional focusing of high-energy X-ray beams.

Accepted 14 June 2017

Characterization of AIIIBV superlattices by means of synchrotron diffraction topography and high-resolution X-ray diffraction

New possibilities are presented for the characterization of superlattices by means of section diffraction topography and high-resolution diffraction.

Accepted 7 June 2017

Hybrid multiple diffraction in semipolar wurtzite materials: (\bf 01\overline{1}2)-oriented ZnMgO/ZnO heterostructures as an illustration

Hybrid multiple diffraction has been employed to analyze r-oriented heterostructures. The study has been applied to the Zn1−xMgxO/ZnO system.

Accepted 2 June 2017

Evaluation of grain-average stress tensor in a tensile-deformed Al–Mn polycrystal by high-energy X-ray diffraction

A method for accurate determination of grain-average strain/stress tensors in polycrystalline aggregates is presented and applied to characterize their evolution in a tensile-deformed Al–Mn polycrystal.

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Journal logoJournal of Synchrotron Radiation Journal of
Synchrotron Radiation

Accepted 10 July 2017

Mutual optical intensity propagation through non-ideal mirrors

A simulation method based on the mutual optical intensity model is developed for simulating the propagation of partially coherent radiation through non-ideal mirrors.

Accepted 7 July 2017

In operando qu­antitation of Li concentration for a commercial Li-ion rechargeable battery using high-energy X-ray Compton scattering

Line-shape analysis of a Compton-scattered X-ray energy spectrum has revealed the Li concentration in a battery under in operando conditions.

Accepted 3 July 2017

Investigation of nanoparticulate silicon as printed layers using scanning electron microscopy, transmission electron microscopy, X-ray absorption spectroscopy and X-ray photoelectron spectroscopy


Accepted 3 July 2017

Strategies for high-throughput focused-beam ptychography

X-ray ptychography is being utilized for a wide range of imaging experiments with a resolution beyond the limit of the X-ray optics used. Here. strategies for data sampling and for increasing imaging throughput when the specimen is at the focus of an X-ray beam are discussed, and the tradeoffs between large and small illumination spots are examined.

Accepted 29 June 2017

Observation of an optical vortex beam from a helical undulator in the XUV region

An optical vortex beam carrying an orbital angular momentum of l\hbar (l = ±1) per photon was produced as the second-harmonic radiation from a helical undulator. The helical wavefront of the optical vortex beam was verified though an interference experiment.

Accepted 27 June 2017

Characterization of individual stacking faults in a wurtzite GaAs nanowire by nanobeam X-ray diffraction


Accepted 27 June 2017

Flyscan opportunities in medicine: the case of quantum rattle based on gold quantum dots

A complete set of data is presented, acquired using the Flyscan method after injection of gold-cluster-enriched mesoporous silica nanospheres, used as potential theranostic vectors, into rats.

Accepted 20 June 2017

Estimating the absolute flux distribution for a synchrotron X-ray beam using ionization-chamber measurements with various filters

The absolute flux distribution for a polychromatic synchrotron X-ray beam is obtained from an extensive set of accurate filter-transmission measurements. The technique is also demonstrated for a monochromatic X-ray beam for which there is significant harmonic contamination.

Accepted 19 June 2017

Micro-beam Laue alignment of multi-reflection Bragg coherent diffraction imaging measurements

A new micro-beam Laue diffraction approach for the rapid, reliable alignment of multi-reflection Bragg coherent diffraction imaging measurements of arbitrarily oriented micro-crystals is presented. This approach is used to map out the full 3D-resolved lattice strain and stress tensors in a focused ion beam machined micro-crystal.

Accepted 19 June 2017

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Journal logoIUCrData
IUCrData

Accepted 24 July 2017

5-Nitro-1-(prop-2-en-1-yl)-1H-indazole

In the crystal, the title mol­ecule forms zigzag chains running parallel to the c axis through weak C—H⋯O hydrogen bonds. The chains pack to form layers approximately parallel to (100) aided by additional weak C—H⋯O hydrogen bonds.

Accepted 24 July 2017

(10R,13R)-17-(6-Hy­droxy-5-methyl­heptan-2-yl)-10,13-di­methyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetra­deca­hydro-1H-cyclo­penta­[a]phen­anthren-3-ol hemihydrate: a bioactive steroid isolated from the Indian herb Artemisia reticulata

The title tetra­cyclic steroidal compound was isolated from the Indian herb A. reticulata. It crystallizes with two independent mol­ecules in the asymmetric unit together with a single water mol­ecule that links the two mol­ecules via O—H⋯O hydrogen bonds.

Accepted 24 July 2017

5-Methyl­pyrazine-2-carboxamide

Hydrogen bonding is the key component in the crystallization of 5-methyl­pyrazine-2-carboxamide.

Accepted 24 July 2017

N-[4-(4-Fluoro­phen­yl)-1,3-thia­zol-2-yl]-3-(4-meth­oxy­phen­yl)-4-methyl­benzamide

Mol­ecules of the title thia­zole derivative are linked via strong N—H⋯O hydrogen bonds forming C(11) chains along [001].

Accepted 23 July 2017

[μ-1,4-Bis(di­phenyl­phosphan­yl)butane]­bis­{(4-benzyl-2-neo­pentyl-1,2,4-triazol-3-yl­idene)[(1,2,5,6-η)-cyclo­octa-1,5-diene]iridium(I)} bis­(tetra­fluoro­borate) di­chloro­methane disolvate

The title mol­ecule lies about an inversion center located at the mid-point of the butane chain of the phosphine ligand. The diphosphine ligand acts as a bridge between the two metal centers. This is the first structural report of a complex where the square-planar iridium centers are bridged by a phosphine ligand, and it is of inter­est with respect to catalysis in transfer hydrogenation reactions.


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