[Culture] :
To strengthen the global competitiveness of K-contents, eleven organizations will pool their resources to create a strategic fund worth approximately 600 billion won, or over 454 million U.S. dollars.
The Ministry of Culture, Sports and Tourism and the Ministry of Science and ICT announced Wednesday that ...
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[Culture] :
KBS hit drama "Winter Sonata" which led the Korean Wave in the 2000s will be released as a theatrical film in Japan next year.
Pan Entertainment, which produced the show, announced Monday that it had decided to release a film version after receiving continuous requests from Japanese distributors and ...
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[Culture] :
South Korea's first Nobel laureate in literature, Han Kang, said she is surprised and absolutely honored to have won the prestigious prize.
In a phone interview with the Swedish Academy, which awards the Nobel prizes, Han expressed appreciation for all the support she’s received.
Asked for a comment ...
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If you've had a grocery store California roll or mixed seafood salad, you've probably eaten imitation crab meat. But what is imitation crab, exactly?
Start your week off right with NVee and DJ Hyerim in another exciting episode of I Feel You! Today, they’re spilling stories about everything from their school days and being the coolest aunts...
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[Economy] :
Global investment banks have slashed their growth outlook for South Korea for this year.
According to the Korea Center for International Finance on Friday, the growth forecast by eight foreign investment banks averaged two-point-three percent at the end of October, representing a zero-point-two percentage ...
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[Economy] :
The nation added 83-thousand jobs in October, with job growth falling below 100-thousand for the first time in four months.
According to Statistics Korea on Wednesday, the number of employed people stood at 28-point-eight million last month, up 83-thousand from the same month last year.
Job growth fell ...
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1,2-Bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene formed its own spherulites by sublimation onto the hydrophilic surfaces of the (0001) planes of α-quartz and sapphire substrates. The formation of different morphologies of these spherulites was attributed to the surface properties of each substrate. Depending on the morphology of the spherulites, hollow rod crystals with cross sections of different sizes and shapes and branching structures were generated on the surfaces of the spherulites.
The rotating substrate method of crystallite deposition is modeled, allowing computation of effective material coefficients of the layers resulting from the averaging. A worked numerical example particularized to 6mm ZnO is provided.
Sublimation methods utilizing the surface properties of substrates can address the challenge of controlling hollow morphologies in rod crystals. Spherulites were formed on the hydrophilic surface of the (0001) planes of α-quartz and sapphire substrates by sublimation of 1,2-bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene (1a). Various types of hollow morphologies, distinguished by the size and shape of their cross sections and by the presence or absence of branching structures, were formed separately on α-quartz and sapphire substrates. Such precise control of the hollow morphologies was attributed to the wettability of each substrate, leading to the formation of spherulites of 1a. In addition, it was indicated that the formation process of the surface morphologies of spherulites was associated with the hollow morphologies of rod crystals of 1a.
In electron diffraction, thermal atomic motion produces incoherent scattering over a relatively wide angular range, which appears as a diffuse background that is usually subtracted from measurements of Bragg spot intensities in structure solution methods. The transfer of electron flux from Bragg spots to diffuse scatter is modelled using complex scattering factors f + if' in the Bloch wave methodology. In a two-beam Einstein model the imaginary `absorptive' scattering factor f' can be obtained by the evaluation of an integral containing f over all possible scattering angles. While more sophisticated models of diffuse scatter are widely used in the electron microscopy community, it is argued in this paper that this simple model is appropriate for current structure solution and refinement methods. The two-beam model is a straightforward numerical calculation, but even this simplistic approach can become time consuming for simulations of materials with large numbers of atoms in the unit cell and/or many incident beam orientations. Here, a parameterized form of f' is provided for 103 elements as neutral, spherical atoms that reduces calculation time considerably.
Analytical calculations of absorption corrections for X-ray powder diffraction experiments on non-ideal samples with surface roughness, porosity or absorption contrasts from multiple phases require complex mathematical models to represent their material distribution. In a computational approach to this problem, a practicable ray-tracing algorithm is formulated which is capable of simulating angle-dependent absorption corrections in reflection geometry for any given rasterized sample model. Single or multiphase systems with arbitrary surface roughness, porosity and spatial distribution of the phases in any combination can be modeled on a voxel grid by assigning respective values to each voxel. The absorption corrections are calculated by tracing the attenuation of X-rays along their individual paths via a modified shear-warp algorithm. The algorithm is presented in detail and the results of simulated absorption corrections on samples with various surface modulations are discussed in the context of published experimental results.
Conjugation is the process by which plasmids, including those that carry antibiotic-resistance genes, are mobilized from one bacterium (the donor) to another (the recipient). The conjugation efficiency of IncF-like plasmids relies on the formation of mating-pair stabilization via intimate interactions between outer membrane proteins on the donor (a plasmid-encoded TraN isoform) and recipient bacteria. Conjugation of the R100-1 plasmid into Escherichia coli and Klebsiella pneumoniae (KP) recipients relies on pairing between the plasmid-encoded TraNα in the donor and OmpW in the recipient. Here, the crystal structure of K. pneumoniae OmpW (OmpWKP) is reported at 3.2 Å resolution. OmpWKP forms an eight-stranded β-barrel flanked by extracellular loops. The structures of E. coli OmpW (OmpWEC) and OmpWKP show high conservation despite sequence variability in the extracellular loops.
AnACor2.0 significantly accelerates the calculation of analytical absorption corrections in long-wavelength crystallography, achieving up to 175× speed improvements. This enhancement is achieved through innovative sampling techniques, bisection and gridding methods, and optimized CUDA implementations, ensuring efficient and accurate results.
Analytical absorption corrections are employed in scaling diffraction data for highly absorbing samples, such as those used in long-wavelength crystallography, where empirical corrections pose a challenge. AnACor2.0 is an accelerated software package developed to calculate analytical absorption corrections. It accomplishes this by ray-tracing the paths of diffracted X-rays through a voxelized 3D model of the sample. Due to the computationally intensive nature of ray-tracing, the calculation of analytical absorption corrections for a given sample can be time consuming. Three experimental datasets (insulin at λ = 3.10 Å, thermolysin at λ = 3.53 Å and thaumatin at λ = 4.13 Å) were processed to investigate the effectiveness of the accelerated methods in AnACor2.0. These methods demonstrated a maximum reduction in execution time of up to 175× compared with previous methods. As a result, the absorption factor calculation for the insulin dataset can now be completed in less than 10 s. These acceleration methods combine sampling, which evaluates subsets of crystal voxels, with modifications to standard ray-tracing. The bisection method is used to find path lengths, reducing the complexity from O(n) to O(log2 n). The gridding method involves calculating a regular grid of diffraction paths and using interpolation to find an absorption correction for a specific reflection. Additionally, optimized and specifically designed CUDA implementations for NVIDIA GPUs are utilized to enhance performance. Evaluation of these methods using simulated and real datasets demonstrates that systematic sampling of the 3D model provides consistently accurate results with minimal variance across different sampling ratios. The mean difference of absorption factors from the full calculation (without sampling) is at most 2%. Additionally, the anomalous peak heights of sulfur atoms in the Fourier map show a mean difference of only 1% compared with the full calculation. This research refines and accelerates the process of analytical absorption corrections, introducing innovative sampling and computational techniques that significantly enhance efficiency while maintaining accurate results.
X-ray spectroscopy is a valuable technique for the study of many materials systems. Characterizing reactions in situ and operando can reveal complex reaction kinetics, which is crucial to understanding active site composition and reaction mechanisms. In this project, the design, fabrication and testing of an open-source and easy-to-fabricate electrochemical cell for in situ electrochemistry compatible with X-ray absorption spectroscopy in both transmission and fluorescence modes are accomplished via windows with large opening angles on both the upstream and downstream sides of the cell. Using a hobbyist computer numerical control machine and free 3D CAD software, anyone can make a reliable electrochemical cell using this design. Onion-like carbon nanoparticles, with a 1:3 iron-to-cobalt ratio, were drop-coated onto carbon paper for testing in situ X-ray absorption spectroscopy. Cyclic voltammetry of the carbon paper showed the expected behavior, with no increased ohmic drop, even in sandwiched cells. Chronoamperometry was used to apply 0.4 V versus reversible hydrogen electrode, with and without 15 min of oxygen purging to ensure that the electrochemical cell does not provide any artefacts due to gas purging. The XANES and EXAFS spectra showed no differences with and without oxygen, as expected at 0.4 V, without any artefacts due to gas purging. The development of this open-source electrochemical cell design allows for improved collection of in situ X-ray absorption spectroscopy data and enables researchers to perform both transmission and fluorescence simultaneously. It additionally addresses key practical considerations including gas purging, reduced ionic resistance and leak prevention.
Experimental characterization of the structural, electronic and dynamic properties of dilute systems in aqueous solvents, such as nanoparticles, molecules and proteins, are nowadays an open challenge. X-ray absorption spectroscopy (XAS) is probably one of the most established approaches to this aim as it is element-specific. However, typical dilute systems of interest are often composed of light elements that require extreme-ultraviolet to soft X-ray photons. In this spectral regime, water and other solvents are rather opaque, thus demanding radical reduction of the solvent volume and removal of the liquid to minimize background absorption. Here, we present an experimental endstation designed to operate a liquid flat jet of sub-micrometre thickness in a vacuum environment compatible with extreme ultraviolet/soft XAS measurements in transmission geometry. The apparatus developed can be easily connected to synchrotron and free-electron-laser user-facility beamlines dedicated to XAS experiments. The conditions for stable generation and control of the liquid flat jet are analyzed and discussed. Preliminary soft XAS measurements on some test solutions are shown.
This study introduces a novel iterative Bragg peak removal with automatic intensity correction (IBR-AIC) methodology for X-ray absorption spectroscopy (XAS), specifically addressing the challenge of Bragg peak interference in the analysis of crystalline materials. The approach integrates experimental adjustments and sophisticated post-processing, including an iterative algorithm for robust calculation of the scaling factor of the absorption coefficients and efficient elimination of the Bragg peaks, a common obstacle in accurately interpreting XAS data, particularly in crystalline samples. The method was thoroughly evaluated on dilute catalysts and thin films, with fluorescence mode and large-angle rotation. The results underscore the technique's effectiveness, adaptability and substantial potential in improving the precision of XAS data analysis. While demonstrating significant promise, the method does have limitations related to signal-to-noise ratio sensitivity and the necessity for meticulous angle selection during experimentation. Overall, IBR-AIC represents a significant advancement in XAS, offering a pragmatic solution to Bragg peak contamination challenges, thereby expanding the applications of XAS in understanding complex materials under diverse experimental conditions.
High energy resolution fluorescence detected X-ray absorption spectroscopy is a powerful method for probing the electronic structure of functional materials. The X-ray penetration depth and photon-in/photon-out nature of the method allow operando experiments to be performed, in particular in electrochemical cells. Here, operando high-resolution X-ray absorption measurements of a BiVO4 photoanode are reported, simultaneously probing the local electronic states of both cations. Small but significant variations of the spectral lineshapes induced by the applied potential were observed and an explanation in terms of the occupation of electronic states at or near the band edges is proposed.
The New Advanced Telescope for High ENergy Astrophysics (NewAthena) will be the largest space-based X-ray observatory ever built. It will have an effective area above 1.1 m2 at 1 keV, which corresponds to a polished mirror surface of about 300 m2 due to the grazing incidence. As such a mirror area is not achievable with an acceptable mass even with nested shells, silicon pore optics (SPO) technology will be utilized. In the PTB laboratory at BESSY II, two dedicated beamlines are in use for their characterization with monochromatic radiation at 1 keV and a low divergence well below 2 arcsec: the X-ray Pencil Beam Facility (XPBF 1) and the X-ray Parallel Beam Facility (XPBF 2.0), where beam sizes up to 8 mm × 8 mm are available while maintaining low beam divergence. This beamline is used for characterizing mirror stacks and controlling the focusing properties of mirror modules (MMs) – consisting of four mirror stacks – during their assembly at the beamline. A movable CCD based camera system 12 m from the MM registers the direct and the reflected beams. The positioning of the detector is verified by a laser tracker. The energy-dependent reflectance in double reflection through the pores of an MM with an Ir coating was measured at the PTB four-crystal monochromator beamline in the photon energy range 1.75 keV to 10 keV, revealing the effects of the Ir M edges. The measured reflectance properties are in agreement with the design values to achieve the envisaged effective area.
The differentially pumped rare-gas filter at the end of the VUV beamline of the Swiss Light Source has been adapted to house a windowless absorption cell for gases. Absorption spectra can be recorded from 7 eV to up to 21 eV photon energies routinely, as shown by a new water and nitrous oxide absorption spectrum. By and large, the spectra agree with previously published ones both in terms of resonance energies and absorption cross sections, but that of N2O exhibits a small shift in the { ilde{f D}} band and tentative fine structures that have not yet been fully described. This setup will facilitate the measurement of absorption spectra in the VUV above the absorption edge of LiF and MgF2 windows. It will also allow us to carry out condensed-phase measurements on thin liquid sheets and solid films. Further development options are discussed, including the recording of temperature-dependent absorption spectra, a stationary gas cell for calibration measurements, and the improvement of the photon energy resolution.
Accurate analysis of the rich information contained within X-ray spectra usually calls for detailed electronic structure theory simulations. However, density functional theory (DFT), time-dependent DFT and many-body perturbation theory calculations increasingly require the use of advanced codes running on high-performance computing (HPC) facilities. Consequently, many researchers who would like to augment their experimental work with such simulations are hampered by the compounding of nontrivial knowledge requirements, specialist training and significant time investment. To this end, we present Web-CONEXS, an intuitive graphical web application for democratizing electronic structure theory simulations. Web-CONEXS generates and submits simulation workflows for theoretical X-ray absorption and X-ray emission spectroscopy to a remote computing cluster. In the present form, Web-CONEXS interfaces with three software packages: ORCA, FDMNES and Quantum ESPRESSO, and an extensive materials database courtesy of the Materials Project API. These software packages have been selected to model diverse materials and properties. Web-CONEXS has been conceived with the novice user in mind; job submission is limited to a subset of simulation parameters. This ensures that much of the simulation complexity is lifted and preliminary theoretical results are generated faster. Web-CONEXS can be leveraged to support beam time proposals and serve as a platform for preliminary analysis of experimental data.
The paper considers the possibility of using the diamond-silicon carbide composite Skeleton® with a technological coating of polycrystalline silicon as a substrate for X-ray mirrors used with powerful synchrotron radiation sources (third+ and fourth generation). Samples were studied after polishing to provide the following surface parameters: root-mean-square flatness ≃ 50 nm, micro-roughness on the frame 2 µm × 2 µm σ ≃ 0.15 nm. The heat capacity, thermal conductivity and coefficient of linear thermal expansion were investigated. For comparison, a monocrystalline silicon sample was studied under the same conditions using the same methods. The value of the coefficient of linear thermal expansion turned out to be higher than that of monocrystalline silicon and amounted to 4.3 × 10−6 K−1, and the values of thermal conductivity (5.0 W cm−1 K−1) and heat capacity (1.2 J K−1 g−1) also exceeded the values for Si. Thermally induced deformations of both Skeleton® and monocrystalline silicon samples under irradiation with a CO2 laser beam have also been experimentally studied. Taking into account the obtained thermophysical constants, the calculation of thermally induced deformation under irradiation with hard (20 keV) X-rays showed almost three times less deformation of the Skeleton® sample than of the monocrystalline silicon sample.
Under DAPHNE4NFDI, the X-ray absorption spectroscopy (XAS) reference database, RefXAS, has been set up. For this purpose, we developed a method to enable users to submit a raw dataset, with its associated metadata, via a dedicated website for inclusion in the database. Implementation of the database includes an upload of metadata to the scientific catalogue and an upload of files via object storage, with automated query capabilities through a web server and visualization of the data and files. Based on the mode of measurements, quality criteria have been formulated for the automated check of any uploaded data. In the present work, the significant metadata fields for reusability, as well as reproducibility of results (FAIR data principles), are discussed. Quality criteria for the data uploaded to the database have been formulated and assessed. Moreover, the usability and interoperability of available XAS data/file formats have been explored. The first version of the RefXAS database prototype is presented, which features a human verification procedure, currently being tested with a new user interface designed specifically for curators; a user-friendly landing page; a full list of datasets; advanced search capabilities; a streamlined upload process; and, finally, a server-side automatic authentication and (meta-) data storage via MongoDB, PostgreSQL and (data-) files via relevant APIs.
Beauveriolides, including the main beauveriolide I {systematic name: (3R,6S,9S,13S)-9-benzyl-13-[(2S)-hexan-2-yl]-6-methyl-3-(2-methylpropyl)-1-oxa-4,7,10-triazacyclotridecane-2,5,8,11-tetrone, C27H41N3O5}, are a series of cyclodepsipeptides that have shown promising results in the treatment of Alzheimer's disease and in the prevention of foam cell formation in atherosclerosis. Their crystal structure studies have been difficult due to their tiny crystal size and fibre-like morphology, until now. Recent developments in 3D electron diffraction methodology have made it possible to accurately study the crystal structures of submicron crystals by overcoming the problems of beam sensitivity and dynamical scattering. In this study, the absolute structure of beauveriolide I was determined by 3D electron diffraction. The cyclodepsipeptide crystallizes in the space group I2 with lattice parameters a = 40.2744 (4), b = 5.0976 (5), c = 27.698 (4) Å and β = 105.729 (6)°. After dynamical refinement, its absolute structure was determined by comparing the R factors and calculating the z-scores of the two possible enantiomorphs of beauveriolide I.
X-ray and electron diffraction methods independently identify the S-enantiomer of Berkecoumarin [systematic name: (S)-8-hydroxy-3-(2-hydroxypropyl)-6-methoxy-2H-chromen-2-one]. Isolated from Berkeley Pit Lake Penicillium sp., Berkecoumarin is a natural product with a light-atom composition (C13H14O5) that challenges in-house absolute structure determination by anomalous scattering. This study further demonstrates the utility of dynamical refinement of electron-diffraction data for absolute structure determination.
The technique of time-resolved macromolecular crystallography (TR-MX) has recently been rejuvenated at synchrotrons, resulting in the design of dedicated beamlines. Using pump–probe schemes, this should make the mechanistic study of photoactive proteins and other suitable systems possible with time resolutions down to microseconds. In order to identify relevant time delays, time-resolved spectroscopic experiments directly performed on protein crystals are often desirable. To this end, an instrument has been built at the icOS Lab (in crystallo Optical Spectroscopy Laboratory) at the European Synchrotron Radiation Facility using reflective focusing objectives with a tuneable nanosecond laser as a pump and a microsecond xenon flash lamp as a probe, called the TR-icOS (time-resolved icOS) setup. Using this instrument, pump–probe spectra can rapidly be recorded from single crystals with time delays ranging from a few microseconds to seconds and beyond. This can be repeated at various laser pulse energies to track the potential presence of artefacts arising from two-photon absorption, which amounts to a power titration of a photoreaction. This approach has been applied to monitor the rise and decay of the M state in the photocycle of crystallized bacteriorhodopsin and showed that the photocycle is increasingly altered with laser pulses of peak fluence greater than 100 mJ cm−2, providing experimental laser and delay parameters for a successful TR-MX experiment.
The Mycobacterium tuberculosis trifunctional enzyme (MtTFE) is an α2β2 tetrameric enzyme in which the α-chain harbors the 2E-enoyl-CoA hydratase (ECH) and 3S-hydroxyacyl-CoA dehydrogenase (HAD) active sites, and the β-chain provides the 3-ketoacyl-CoA thiolase (KAT) active site. Linear, medium-chain and long-chain 2E-enoyl-CoA molecules are the preferred substrates of MtTFE. Previous crystallographic binding and modeling studies identified binding sites for the acyl-CoA substrates at the three active sites, as well as the NAD binding pocket at the HAD active site. These studies also identified three additional CoA binding sites on the surface of MtTFE that are different from the active sites. It has been proposed that one of these additional sites could be of functional relevance for the substrate channeling (by surface crawling) of reaction intermediates between the three active sites. Here, 226 fragments were screened in a crystallographic fragment-binding study of MtTFE crystals, resulting in the structures of 16 MtTFE–fragment complexes. Analysis of the 121 fragment-binding events shows that the ECH active site is the `binding hotspot' for the tested fragments, with 41 binding events. The mode of binding of the fragments bound at the active sites provides additional insight into how the long-chain acyl moiety of the substrates can be accommodated at their proposed binding pockets. In addition, the 20 fragment-binding events between the active sites identify potential transient binding sites of reaction intermediates relevant to the possible channeling of substrates between these active sites. These results provide a basis for further studies to understand the functional relevance of the latter binding sites and to identify substrates for which channeling is crucial.
An X-ray absorption spectroscopy (XAS) electrochemical cell was used to collect high-quality XAS measurements of N-truncated Cu:amyloid-β (Cu:Aβ) samples under near-physiological conditions. N-truncated Cu:Aβ peptide complexes contribute to oxidative stress and neurotoxicity in Alzheimer's patients' brains. However, the redox properties of copper in different Aβ peptide sequences are inconsistent. Therefore, the geometry of binding sites for the copper binding in Aβ4–8/12/16 was determined using novel advanced extended X-ray absorption fine structure (EXAFS) analysis. This enables these peptides to perform redox cycles in a manner that might produce toxicity in human brains. Fluorescence XAS measurements were corrected for systematic errors including defective-pixel data, monochromator glitches and dispersion of pixel spectra. Experimental uncertainties at each data point were measured explicitly from the point-wise variance of corrected pixel measurements. The copper-binding environments of Aβ4–8/12/16 were precisely determined by fitting XAS measurements with propagated experimental uncertainties, advanced analysis and hypothesis testing, providing a mechanism to pursue many similarly complex questions in bioscience. The low-temperature XAS measurements here determine that CuII is bound to the first amino acids in the high-affinity amino-terminal copper and nickel (ATCUN) binding motif with an oxygen in a tetragonal pyramid geometry in the Aβ4–8/12/16 peptides. Room-temperature XAS electrochemical-cell measurements observe metal reduction in the Aβ4–16 peptide. Robust investigations of XAS provide structural details of CuII binding with a very different bis-His motif and a water oxygen in a quasi-tetrahedral geometry. Oxidized XAS measurements of Aβ4–12/16 imply that both CuII and CuIII are accommodated in an ATCUN-like binding site. Hypotheses for these CuI, CuII and CuIII geometries were proven and disproven using the novel data and statistical analysis including F tests. Structural parameters were determined with an accuracy some tenfold better than literature claims of past work. A new protocol was also developed using EXAFS data analysis for monitoring radiation damage. This gives a template for advanced analysis of complex biosystems.
MltG, a membrane-bound lytic transglycosylase, has roles in terminating glycan polymerization in peptidoglycan and incorporating glycan chains into the cell wall, making it significant in bacterial cell-wall biosynthesis and remodeling. This study provides the first reported MltG structure from Mycobacterium abscessus (maMltG), a superbug that has high antibiotic resistance. Our structural and biochemical analyses revealed that MltG has a flexible peptidoglycan-binding domain and exists as a monomer in solution. Further, the putative active site of maMltG was disclosed using structural analysis and sequence comparison. Overall, this study contributes to our understanding of the transglycosylation reaction of the MltG family, aiding the design of next-generation antibiotics targeting M. abscessus.
A significant part of the present and future of optoelectronic devices lies on thin multilayer heterostructures. Their optical properties depend strongly on strain, being essential to the knowledge of the stress level to optimize the growth process. Here the structural and microstructural characteristics of sub-micron a-ZnO epilayers (12 to 770 nm) grown on r-sapphire by metal–organic chemical vapour deposition are studied. Morphological and structural studies have been made using scanning electron microscopy and high-resolution X-ray diffraction. Plastic unit-cell distortion and corresponding strain have been determined as a function of film thickness. A critical thickness has been observed as separating the non-elastic/elastic states with an experimental value of 150–200 nm. This behaviour has been confirmed from ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy measurements. An equation that gives the balance of strains is proposed as an interesting method to experimentally determine this critical thickness. It is concluded that in the thinnest films an elongation of the Zn—O bond takes place and that the plastic strained ZnO films relax through nucleation of misfit dislocations, which is a consequence of three-dimensional surface morphology.
Three new 1H-indole derivatives, namely, 2-(bromomethyl)-3-methyl-1-(phenylsulfonyl)-1H-indole, C16H14BrNO2S, (I), 2-[(E)-2-(2-bromo-5-methoxyphenyl)ethenyl]-3-methyl-1-(phenylsulfonyl)-1H-indole, C24H20BrNO3S, (II), and 2-[(E)-2-(2-bromophenyl)ethenyl]-3-methyl-1-(phenylsulfonyl)-1H-indole, C23H18BrNO2S, (III), exhibit nearly orthogonal orientations of their indole ring systems and sulfonyl-bound phenyl rings. Such conformations are favourable for intermolecular bonding involving sets of slipped π–π interactions between the indole systems and mutual C—H⋯π hydrogen bonds, with the generation of two-dimensional monoperiodic patterns. The latter are found in all three structures, in the form of supramolecular columns with every pair of successive molecules related by inversion. The crystal packing of the compounds is additionally stabilized by weaker slipped π–π interactions between the outer phenyl rings (in II and III) and by weak C—H⋯O, C—H⋯Br and C—H⋯π hydrogen bonds. The structural significance of the different kinds of interactions agree with the results of a Hirshfeld surface analysis and the calculated interaction energies. In particular, the largest interaction energies (up to −60.8 kJ mol−1) are associated with pairing of antiparallel indole systems, while the energetics of weak hydrogen bonds and phenyl π–π interactions are comparable and account for 13–34 kJ mol−1.
Bis(2-methylpyridine)gold(I) dibromidoaurate(I), [Au(C6H7N)2][AuBr2], (1), crystallizes in space group C2/c with Z = 4. Both gold atoms lie on twofold axes and are connected by an aurophilic contact. A second aurophilic contact leads to infinite chains of alternating cations and anions parallel to the b axis, and the residues are further connected by a short H⋯Au contact and a borderline Br⋯Br contact. Bis(3-methylpyridine)gold(I) dibromidoaurate(I), [Au(C6H7N)2][AuBr2], (2), crystallizes in space group C2/m with Z = 2. Both gold atoms lie on special positions with symmetry 2/m and are connected by an aurophilic contact; all other atoms except for one methyl hydrogen lie in mirror planes. The extended structure is closely analogous to that of 1, although the structures are formally not isotypic. Bis(3,5-dimethylpyridine)gold(I) dichloridoaurate(I), [Au(C7H9N)2][AuCl2], (3) crystallizes in space group Poverline{1} with Z = 2. The cation lies on a general position, and there are two independent anions in which the gold atoms lie on inversion centres. The cation and one anion associate via three short H⋯Cl contacts to form a ribbon structure parallel to the b axis; aurophilic contacts link adjacent ribbons. Bis(3,5-dimethylpyridine)gold(I) dibromidoaurate(I), [Au(C7H9N)2][AuBr2], (4) is isotypic to 3. Attempts to make similar compounds involving 2-bromopyridine led instead to 2-bromopyridinium dibromidoaurate(I)–2-bromopyridine (1/1), (C5H5BrN)[AuBr2]·C5H4BrN, (5), which crystallizes in space group Poverline{1} with Z = 2; all atoms lie on general positions. The 2-bromopyridinium cation is linked to the 2-bromopyridine molecule by an N—H⋯N hydrogen bond. Two formula units aggregate to form inversion-symmetric dimers involving Br⋯Br, Au⋯Br and H⋯Br contacts.
The structures of seven gold(III) halide derivatives of general formula LAuX3 (L = methylpyridines or dimethylpyridines, X = Cl or Br) are presented: trichlorido(2-methylpyridine)gold(III), [AuCl3(C6H7N)], 1 (as two polymorphs 1a and 1b); tribromido(2-methylpyridine)gold(III), [AuBr3(C6H7N)], 2; tribromido(3-methylpyridine)gold(III), [AuBr3(C6H7N)], 3; tribromido(2,4-dimethylpyridine)gold(III), [AuBr3(C7H9N)], 4; trichlorido(3,5-dimethylpyridine)gold(III), [AuCl3(C7H9N)], 5; tribromido(3,5-dimethylpyridine)gold(III), [AuBr3(C7H9N)], 6, and trichlorido(2,6-dimethylpyridine)gold(III), [AuCl3(C7H9N)], 7. Additionally, the structure of 8, the 1:1 adduct of 2 and 6, [AuBr3(C6H7N)]·[AuBr3(C7H9N)], is included. All the structures crystallize solvent-free, and all have Z' = 1 except for 5 and 7, which display crystallographic twofold rotation symmetry, and 4, which has Z' = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals (1a, 1b, 2 and 8) were non-merohedral twins, and these structures were refined using the ‘HKLF 5’ method. The largest interplanar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the pyridine ring. The Au—N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au—X)2, with antiparallel Au—X bonds linked by Au⋯X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary interactions (Au⋯X or X⋯X contacts, `weak' C—H⋯X hydrogen bonds) to form chain, double chain (`ladder') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C—H⋯Cl hydrogen bonds combined with Cl⋯Cl contacts (1b) or Cl⋯π contacts (7). The packing patterns of seven further complexes LAuX3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1–8.
The absolute configuration of the title compound, C13H16O4, determined as 1S,2R,3S,4R based on the synthetic pathway, was confirmed by single-crystal X-ray diffraction. The molecule is a relevant intermediary for the synthesis of speciosins, epoxyquinoides or their analogues. The molecule contains fused five- and six-membered rings with two free hydroxyl groups and two protected as an isopropylidenedioxo ring. The packing is directed by hydrogen bonds that define double planes of molecules laying along the ab plane and van der Waals interactions between aliphatic chains that point outwards of the planes.
This work presents observations of symmetry breakages in the intensity distributions of near-zone-axis convergent-beam electron diffraction (CBED) patterns that can only be explained by the symmetry of the specimen and not the symmetry of the unit cell describing the atomic structure of the material. The specimen is an aluminium–copper–tin alloy containing voids many tens of nanometres in size within continuous single crystals of the aluminium host matrix. Several CBED patterns where the incident beam enters and exits parallel void facets without the incident beam being perpendicular to these facets are examined. The symmetries in their intensity distributions are explained by the specimen morphology alone using a geometric argument based on the multislice theory. This work shows that it is possible to deduce nanoscale morphological information about the specimen in the direction of the electron beam – the elusive third dimension in transmission electron microscopy – from the inspection of CBED patterns.
Processing of single-crystal X-ray diffraction data from area detectors can be separated into two steps. First, raw intensities are obtained by integration of the diffraction images, and then data correction and reduction are performed to determine structure-factor amplitudes and their uncertainties. The second step considers the diffraction geometry, sample illumination, decay, absorption and other effects. While absorption is only a minor effect in standard macromolecular crystallography (MX), it can become the largest source of uncertainty for experiments performed at long wavelengths. Current software packages for MX typically employ empirical models to correct for the effects of absorption, with the corrections determined through the procedure of minimizing the differences in intensities between symmetry-equivalent reflections; these models are well suited to capturing smoothly varying experimental effects. However, for very long wavelengths, empirical methods become an unreliable approach to model strong absorption effects with high fidelity. This problem is particularly acute when data multiplicity is low. This paper presents an analytical absorption correction strategy (implemented in new software AnACor) based on a volumetric model of the sample derived from X-ray tomography. Individual path lengths through the different sample materials for all reflections are determined by a ray-tracing method. Several approaches for absorption corrections (spherical harmonics correction, analytical absorption correction and a combination of the two) are compared for two samples, the membrane protein OmpK36 GD, measured at a wavelength of λ = 3.54 Å, and chlorite dismutase, measured at λ = 4.13 Å. Data set statistics, the peak heights in the anomalous difference Fourier maps and the success of experimental phasing are used to compare the results from the different absorption correction approaches. The strategies using the new analytical absorption correction are shown to be superior to the standard spherical harmonics corrections. While the improvements are modest in the 3.54 Å data, the analytical absorption correction outperforms spherical harmonics in the longer-wavelength data (λ = 4.13 Å), which is also reflected in the reduced amount of data being required for successful experimental phasing.
Macromolecular crystallography contributes significantly to understanding diseases and, more importantly, how to treat them by providing atomic resolution 3D structures of proteins. This is achieved by collecting X-ray diffraction images of protein crystals from important biological pathways. Spotfinders are used to detect the presence of crystals with usable data, and the spots from such crystals are the primary data used to solve the relevant structures. Having fast and accurate spot finding is essential, but recent advances in synchrotron beamlines used to generate X-ray diffraction images have brought us to the limits of what the best existing spotfinders can do. This bottleneck must be removed so spotfinder software can keep pace with the X-ray beamline hardware improvements and be able to see the weak or diffuse spots required to solve the most challenging problems encountered when working with diffraction images. In this paper, we first present Bragg Spot Detection (BSD), a large benchmark Bragg spot image dataset that contains 304 images with more than 66 000 spots. We then discuss the open source extensible U-Net-based spotfinder Bragg Spot Finder (BSF), with image pre-processing, a U-Net segmentation backbone, and post-processing that includes artifact removal and watershed segmentation. Finally, we perform experiments on the BSD benchmark and obtain results that are (in terms of accuracy) comparable to or better than those obtained with two popular spotfinder software packages (Dozor and DIALS), demonstrating that this is an appropriate framework to support future extensions and improvements.
Understanding the structure–property relationship in electrocatalysts under working conditions is crucial for the rational design of novel and improved catalytic materials. This paper presents the Aarhus University reactor for electrochemical studies using X-rays (AUREX) operando electrocatalytic flow cell, designed as an easy-to-use versatile setup with a minimal background contribution and a uniform flow field to limit concentration polarization and handle gas formation. The cell has been employed to measure operando total scattering, diffraction and absorption spectroscopy as well as simultaneous combinations thereof on a commercial silver electrocatalyst for proof of concept. This combination of operando techniques allows for monitoring of the short-, medium- and long-range structure under working conditions, including an applied potential, liquid electrolyte and local reaction environment. The structural transformations of the Ag electrocatalyst are monitored with non-negative matrix factorization, linear combination analysis, the Pearson correlation coefficient matrix, and refinements in both real and reciprocal space. Upon application of an oxidative potential in an Ar-saturated aqueous 0.1 M KHCO3/K2CO3 electrolyte, the face-centered cubic (f.c.c.) Ag gradually transforms first to a trigonal Ag2CO3 phase, followed by the formation of a monoclinic Ag2CO3 phase. A reducing potential immediately reverts the structure to the Ag (f.c.c.) phase. Following the electrochemical-reaction-induced phase transitions is of fundamental interest and necessary for understanding and improving the stability of electrocatalysts, and the operando cell proves a versatile setup for probing this. In addition, it is demonstrated that, when studying electrochemical reactions, a high energy or short exposure time is needed to circumvent beam-induced effects.
The lineup from the "Justice League" animated series.; Credit: Warner Bros.
Bruce Timm's DC Comics animated universe, beginning with "Batman: The Animated Series" and continuing with "Superman," "Batman Beyond," "Justice League," "Justice League Unlimited" and more, remains one of the most beloved and critically acclaimed animated runs in existence. The run was so idenified with the producer that it was sometimes called the Timmverse, but the last show in that continuity ended in 2006 and Timm officially stepped down from working with DC animation in 2013.
Now Timm is back. He's providing a darker take than the optimistic world he became known for in "Justice League: Gods and Monsters," a three-part digital series launching spring 2015 that will be tied in with a full-length animated film that comes out later that year, according to a press release.
Timm's also re-teaming with Alan Burnett, who worked with Timm on "Batman: The Animated Series." It's part of DC Comics' efforts to set up their new film "Batman v Superman: Dawn of Justice," which hits in 2016, with the full Justice League film set for 2018.
DC Comics as a whole has been moving in a darker direction with Christopher Nolan's Batman trilogy, the "Man of Steel" reboot of Superman and a more serious direction in many of its comic books. The company has followed in its tradition of epic storytelling, passing on the quips Marvel has popularized in films from "Iron Man" to "Guardians of the Galaxy."
It's yet to be seen if Timm can recapture any of the magic from his classic cartoons, but there's reason to be optimistic for the creator of the series that introduced fan favorite Joker sidekick Harley Quinn, created a new origin for Mr. Freeze that cemented the character in the Batman mythos and led the team reimagining numerous characters in an iconic, broadly appealing way.
If you want to catch up on Timm's legacy, his previous two Justice League series are available on Netflix and Amazon Prime, along with "Batman Beyond," while the Batman and Superman animated series are available on Amazon Prime.
Timm also recently produced a short for the 75th anniversary of Batman called "Strange Days," setting the character in the retro world of the serialized pulp storytelling from the time Batman was originally created. You can watch that below:
Watch the classic opening to "Batman: The Animated Series":
Batman: The Animated Series opening
And, a personal favorite joke from when Lex Luthor and the Flash trade bodies on "Justice League Unlimited":
Liam Neeson stars as Matthew Scudder in "A Walk Among the Tombstones." ; Credit: Universal Pictures
Screenwriter and director Scott Frank has been trying to make “A Walk Among the Tombstones” for more than a decade, but it wasn't until Liam Neeson signed on that his efforts finally came into view.
Based on the Lawrence Block novel, “Tombstones” stars Liam Neeson as Matthew Scudder, an ex-cop working as an unlicensed private investigator. He agrees to help a well-to-do drug trafficker hunt down the kidnappers who have brutally murdered his wife.
Frank wrote the screenplay and, after the departures of other attached directors, Frank decided to step behind the cameras himself.
When he came by The Frame studio, Frank spoke with host John Horn about Neeson's great strengths as an action hero and how he convinced Neeson to sign on to the project.
John Horn: Liam Neeson has evolved in a fascinating way as an action hero. When did you start having conversations with him about this movie, and what was it about him as an actor that made it feel like the right fit?
"Well, what's interesting is that Larry Block, the novelist, had always said, going way back to 2003 or something, that the perfect actor for this, after [he saw] 'Michael Collins'...would be Liam Neeson. Chris Andrews, who is Liam's agent, always loved the script and was always trying to find a way to put it together, and he's the one who gave it to Liam back when D.J. [Caruso] was going to direct. So the first time I met Liam to talk about the movie, I was talking to him as the writer, not as the director of the movie. And then when D.J. fell out to go do a different movie at Sony...we had a conversation about directing the movie.
JH: Was this before or after the first "Taken" had come out?
This was well after the first 'Taken,' this was right before the second 'Taken.'
JH: So Liam is...succeeding as a version of that character, and I wonder if that success cuts both ways, that maybe there's a reluctance on his part to not do something that's quite as similar? Or is that part of your conversation that you have with him?
It absolutely cuts both ways, and that was a huge part of the conversation because there's a kidnapping in this story, and there he is on the telephone for a few minutes at the end of the movie talking to kidnappers, and there are similarities [to 'Taken']. And he knew that was the way to sell the movie, and so he was very reluctant. And I talked to him and I had him watch 'Klute,' and I said, "That's the movie we're gonna make. We're not going to make 'Taken,' we're going to make a movie that's like 'Klute,' or a little bit like 'Dirty Harry,' or one of those old-school '70s films. It's going to feel more like that than an action movie."
JH: Liam Neeson's not physically imposing, but there's something about him that really kind of makes the hair on the back of your neck stand up. What is it about him as an actor in this kind of part?
Well, there's a couple things. One: you believe him. No matter what he's talking about, it seems authentic and true...he has this thing about him that, whatever he's doing, you believe him. Two: he's one of those actors like Gene Hackman where he can convey exposition and make it feel like character. He can talk pages of exposition and make it all feel like it's character and drama — it's a great thing. The other thing about him is that he has this real gravitas, and it almost borders on sadness sometimes; it's interesting when you watch him and you feel like there's all this other life going on behind him.
JH: That he has nothing to lose, in other words.
Nothing to lose, and he says that at one point in the film, but I think it's those things that are all at work at the same time.
The general equation of the δ direct methods is established and applied in its difference form to the definition of one of the two residuals that constitute the SMAR phasing algorithm. These two residuals use the absolute value of ρ and/or the zero conversion of negative Fourier ripples (≥50% of the unit-cell volume). Alternatively, when solved for ρ, the general equation provides a simple derivation of the already known δM tangent formula.
The Pathfinding Partnerships Award from CO-LABS recognizes impactful, collaborative research projects organized by four or more research entities, including federal labs, in Colorado. This year, the Wildfire Research (WiRē) team received this award for their support of evidence-based community wildfire education to help communities live with wildfire.
A waitress wears a face mask while serving at Langer's Delicatessen-Restaurant in Los Angeles on June 15.; Credit: Frederic J. Brown/AFP via Getty Images
Domenico Montanaro | NPRNormal is not easily defined.
The past 15 months, though, have certainly been anything but.
Americans are starting to believe a "sense of normal" is approaching fairly soon, however, according to a new NPR/PBS NewsHour/Marist survey. The poll also found that with the coronavirus receding in this country, mask-wearing is declining and Americans are going out more. But they remain cautious about being in large crowds.
As the country continues to open up, more focus turns to the economy, which cratered during the beginning of the pandemic last year. And Americans are split by race, gender and politics on whether President Biden's ambitious policies are helping or not.
Three months ago, in a similar survey, 49% of adults said the president's policies were strengthening the economy, while 44% said they were weakening it.
Now, that's declined a net of 6 points, as 44% of respondents in the new poll say Biden's policies have strengthened the economy and 45% say the opposite. The percentage who were unsure also jumped 4 points. It's all a little bit of a warning sign for Biden, as he pushes for two large — and expensive — spending packages.
There are significant splits by race and gender:
A quarter of Americans rank inflation as the U.S. economy's top concern. That's followed by wages, unemployment, housing costs, labor shortages, gas prices and interest rates.
But there's a sharp political divide on the question. Republicans and independents rank inflation as their top concern, while for Democrats, it was wages. Just 4% of Republicans said wages were their top concern.
Americans are growing increasingly optimistic about when life will return to a "sense of normal," as the survey labels it.
In April, three-quarters of Americans said they believe it will take six months or more. Now, it's just half. About a quarter (27%) say it will be less than six months, up from 15% two months ago.
People are also growing more comfortable doing certain things, saying they're:
But they are not as comfortable doing others:
While half say they are concerned about another coronavirus surge, almost 9-in-10 U.S. adults with jobs say they are at least somewhat comfortable returning to work.
Notably, a majority (57%) of those with jobs do not believe employers should require COVID-19 vaccines as a condition to return to in-person work.
More than a quarter of Americans say they will not get vaccinated. The most resistant to getting vaccinated continue to be supporters of former President Donald Trump. Half of them say they won't get the shot, the highest of any group surveyed. Trump has touted the vaccine and got it himself.
Since Centers for Disease Control and Prevention guidelines came out, noting that Americans who have been vaccinated can largely set masks aside, there's been a double-digit decline in those saying they wear a mask even when it's not required.
There's also been a double-digit increase in those saying they generally do not wear a mask. In May, 49% said they wore masks even when it was not required. Now, that's just 36%.
One-in-five said they generally do not wear masks. Two months ago, it was less than one-in-10.
Speaking of getting back to normal, a majority of Americans say they plan to take a vacation this summer.
But of the significant minority (45%) who say they aren't taking one, almost three times as many cited affordability (35%) as the main reason for not going, as opposed to concerns about COVID-19 (12%).
Methodology: The poll of 1,115 U.S. adults was conducted using live telephone interviewers from June 22 through June 29. Survey questions were available in English or Spanish. The full sample has a margin of error of plus or minus 3.7 percentage points, with larger margins of error for smaller group subsets.
Copyright 2021 NPR. To see more, visit https://www.npr.org.This content is from Southern California Public Radio. View the original story at SCPR.org.
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A new study shows that the West Antarctic Peninsula is experiencing some of the most rapid climate change on Earth, featuring dramatic increases in temperatures, retreats in glaciers and declines in sea ice. The Southern Ocean absorbs nearly half of the carbon dioxide -- the key greenhouse gas linked to climate change -- that is absorbed by all the world's oceans. The study tapped an unprecedented 25 years of oceanographic measurements in the Southern Ocean and highlights the need for more monitoring in the region. The research revealed that carbon dioxide absorption by surface waters off the West Antarctic Peninsula is linked to the stability of the upper ocean, along with the amount and type of algae present. A stable upper ocean provides algae with ideal growing conditions. During photosynthesis, algae remove carbon dioxide from the surface ocean, which in turn draws carbon dioxide out of the atmosphere. From 1993 to 2017, changes in sea ice dynamics off the West Antarctic Peninsula stabilized the upper ocean, resulting in greater algal concentrations and a shift in the mix of algal species. That's led to a nearly five-fold increase in carbon dioxide absorption during the summertime. The research also found a strong north-south difference in the trend of carbon dioxide absorption. The southern portion of the peninsula, which to date has been less impacted by climate change, experienced the most dramatic increase in carbon dioxide absorption, demonstrating the poleward progression of climate change in the region.
Image credit: Drew Spacht/The Ohio State University
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The company will locate a manufacturing operation in the Catawba Industrial Commons, creating 110 new jobs with an average wage of over $50,000 and investing $15 million over the next five years. It will provide specialized services for parts used in gas turbine engines produced by Siemens, GE, Alstom and Rolls-Royce.
Furniture manufacturer Lee Industries, Inc. plans to expand their manufacturing capabilities in Catawba County by extensively redeveloping and renovating the former Conover Chair facility in Conover, N.C. and adding 75 new employees beginning in late 2011. The company will be hiring cutters, sewers, spring-up associates, inside and outside upholsterers, shipping personnel, support staff and more. The average employee wage is expected to be $41,045, nearly $7,000 more than the average pay for workers living in Catawba County.