mo 11 Most Popular Sports in the World By entertainment.howstuffworks.com Published On :: Thu, 07 Nov 2024 10:25:02 -0500 Thrilling gameplay, dramatic storylines and top-notch talent are all important factors in ensuring a sport's popularity grows and fanbases thrive. The most popular sports in the world are all spectacles of athletic competition that attract large crowds in the stands and around the television. Full Article
mo Emotional Cancer Meets Free-Spirited Aquarius: Compatibility Breakdown By entertainment.howstuffworks.com Published On :: Fri, 08 Nov 2024 05:30:03 -0500 Discover the compatibility between Cancer and Aquarius in love, friendship, and relationships. Learn how their emotional and intellectual traits align or clash. Full Article
mo Aquarius Moon Traits: Understanding the Emotional Landscape By entertainment.howstuffworks.com Published On :: Sat, 09 Nov 2024 05:30:03 -0500 Explore the Aquarius Moon's traits, emotional depth, and how it influences relationships, creativity, and personal growth in astrology. Unlock its mysterious power. Full Article
mo S. Korea Posts Current Account Surplus in September for Fifth Straight Month By world.kbs.co.kr Published On :: Thu, 07 Nov 2024 08:29:44 +0900 [Economy] : The nation posted a current account surplus for the fifth consecutive month in September, on the back of robust exports of semiconductors and other IT products. According to tentative data from the Bank of Korea on Thursday, the current account surplus came to eleven-point-12 billion dollars in ...[more...] Full Article Economy
mo Foreign Investors Sell Stocks for Third Consecutive Month By world.kbs.co.kr Published On :: Fri, 08 Nov 2024 15:39:02 +0900 [Economy] : Foreign investors were net sellers in the South Korean stock market for the third month in October. According to data from the Bank of Korea(BOK) on Friday, foreigners sold a net four-point-17 billion U.S. dollars worth of stocks last month. But the latest figure is lower than September’s total of ...[more...] Full Article Economy
mo KOSPI Down 1.15% on Monday By world.kbs.co.kr Published On :: Mon, 11 Nov 2024 15:47:09 +0900 [Economy] : The benchmark Korea Composite Stock Price Index dipped 29-point-49 points, or one-point-15 percent, on Monday to close at two-thousand-531-point-66. The tech-heavy KOSDAQ slid 14-point-54 points, or one-point-96 percent, to close at 728-point-84.[more...] Full Article Economy
mo Won Weakens, Trading at more than 1,400 per Dollar By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 10:23:54 +0900 [Economy] : The South Korean won weakened past the psychological threshold of 14-hundred won against the U.S. dollar on Tuesday, after Donald Trump’s victory in the U.S. presidential election last week. The South Korean currency traded at 14-hundred-point-seven won per dollar as of 9:05 a.m. Tuesday, six won more ...[more...] Full Article Economy
mo S. Koreans View Marriage, Childrearing More Favorably than 2 Years Ago By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 15:26:49 +0900 [Economy] : South Koreans appear to hold more favorable views of marriage and childrearing than they did two years ago. According to Statistics Korea on Tuesday, 52-point-five percent of some 36-thousand people aged 13 and older polled in May said people should get married, up two-point-five percentage points from ...[more...] Full Article Economy
mo Won Weakens, Trading at More than 1,400 per Dollar By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 16:43:51 +0900 [Economy] : The South Korean won weakened past the psychological threshold of 14-hundred won against the U.S. dollar on Tuesday, after Donald Trump’s victory in the U.S. presidential election last week. The South Korean currency traded at 14-hundred-three-point-five won per dollar as of 3:30 p.m. Tuesday, ...[more...] Full Article Economy
mo KOSPI Slips below 2,500 Threshold for First Time since Black Monday in August By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 17:55:50 +0900 [Economy] : South Korea’s benchmark Korea Composite Stock Price Index(KOSPI) slipped below the two-thousand-500 threshold on Tuesday for the first time since August’s “Black Monday.” The KOSPI dipped 49-point-09 points, or one-point-94 percent, on Tuesday to close at two-thousand-482-point-57. In the ...[more...] Full Article Economy
mo 83,000 Jobs Added in October, Slowest Growth in 4 Months By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 08:29:45 +0900 [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 ...[more...] Full Article Economy
mo Import Prices Jump 2.2% in October, Largest Gain in 6 Months By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 09:13:48 +0900 [Economy] : The country’s import prices jumped more than two percent in October due to the won’s depreciation against the U.S. dollar and a rise in global oil prices. According to data from the Bank of Korea on Wednesday, the country’s import price index reached 137-point-61 in October, up two-point-two ...[more...] Full Article Economy
mo KOSDAQ Falls below 700 for First Time in 2 Months By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 11:20:48 +0900 [Economy] : South Korea’s tech-laden KOSDAQ fell below the 700 mark during trading for the first time in two months. As of 10:12 a.m. Wednesday, the secondary KOSDAQ market stood at 697-point-94, down 12-point-58 points or one-point-77 percent from the previous day. It marks the first time the KOSDAQ has ...[more...] Full Article Economy
mo Natural flood management: is geology more important than trees? - British Geological Survey By news.google.com Published On :: Thu, 23 Nov 2023 08:00:00 GMT Natural flood management: is geology more important than trees? British Geological Survey Full Article
mo Did you feel the earth move? Mini-earthquake recorded on Shropshire/Staffordshire border - Express & Star By news.google.com Published On :: Mon, 14 Oct 2024 07:00:00 GMT Did you feel the earth move? Mini-earthquake recorded on Shropshire/Staffordshire border Express & Star Full Article
mo Trailblazing seismologist named new editor-in-chief of GJI - The Royal Astronomical Society By news.google.com Published On :: Tue, 27 Feb 2024 08:00:00 GMT Trailblazing seismologist named new editor-in-chief of GJI The Royal Astronomical Society Full Article
mo Moving stones: faults, slopes and sediments - British Geological Survey By news.google.com Published On :: Fri, 12 Jan 2024 08:00:00 GMT Moving stones: faults, slopes and sediments British Geological Survey Full Article
mo Washington DC among US cities most vulnerable to space weather, scientists say - The Royal Astronomical Society By news.google.com Published On :: Thu, 18 Jul 2024 07:00:00 GMT Washington DC among US cities most vulnerable to space weather, scientists say The Royal Astronomical Society Full Article
mo BGS signs memorandum of understanding with Serviço Geológico do Brasil - British Geological Survey By news.google.com Published On :: Wed, 10 Apr 2024 07:00:00 GMT BGS signs memorandum of understanding with Serviço Geológico do Brasil British Geological Survey Full Article
mo First national-scale groundwater model in Great Britain developed - British Geological Survey By news.google.com Published On :: Tue, 14 May 2024 10:50:37 GMT First national-scale groundwater model in Great Britain developed British Geological Survey Full Article
mo The Common Ground project - British Geological Survey By news.google.com Published On :: Fri, 23 Feb 2024 14:43:19 GMT The Common Ground project British Geological Survey Full Article
mo Monitoring coastal change from space - British Geological Survey By news.google.com Published On :: Thu, 10 Oct 2024 14:36:15 GMT Monitoring coastal change from space British Geological Survey Full Article
mo Forty years and counting: new topsoil data provides most extensive snapshot of environmental pollution effects - British Geological Survey By news.google.com Published On :: Tue, 01 Oct 2024 07:00:00 GMT Forty years and counting: new topsoil data provides most extensive snapshot of environmental pollution effects British Geological Survey Full Article
mo BGS to update geological maps of Strathmore - British Geological Survey By news.google.com Published On :: Mon, 10 Jun 2024 07:00:00 GMT BGS to update geological maps of Strathmore British Geological Survey Full Article
mo Tracking anharmonic oscillations in the structure of β 1,3-diacetylpyrene By journals.iucr.org Published On :: A recently discovered β polymorph of 1,3-diacetylpyrene has turned out to be a prominent negative thermal expansion material. Its unique properties can be linked to anharmonic oscillations in the crystal structure. The onset and development of anharmonic behavior have been successfully tracked over a wide temperature range by single-crystal X-ray diffraction experiments. Sufficient diffraction data quality combined with modern quantum crystallography tools allowed a thorough analysis of the elusive anharmonic effects for a moderate-scattering purely organic compound. Full Article text
mo Crystal structure of the incommensurate modulated high-pressure phase of the potassium guaninate monohydrate By journals.iucr.org Published On :: Incommensurate phase of potassium guaninate monohydrate is the first example of a modulation in purine derivatives and of a high-pressure incommensurate crystal structure to be solved for an organic compound. Full Article text
mo From `crystallographic accuracy' to `thermodynamic accuracy': a redetermination of the crystal structure of calcium atorvastatin trihydrate (Lipitor®) By journals.iucr.org Published On :: The crystal structure of calcium atorvastatin trihydrate was redetermined from previously published synchrotron powder diffraction data to give a much-improved agreement with two independent density-functional theory calculations. Full Article text
mo Atypical phase transition, twinning and ferroelastic domain structure in bis(ethylenediammonium) tetrabromozincate(II) bromide, [NH3(CH2)2NH3]2[ZnBr4]Br2 By journals.iucr.org Published On :: A unique phase transition, twinning and ferroelastic domain structure in [NH3(CH2)2NH3]2[ZnBr4]Br2 is found. The new additional domain structure is observed at the phase transition on heating, which is preserved after cooling to room temperature. Full Article text
mo Morphological control for hollow rod crystals of a photochromic diarylethene on spherulites by surface properties of substrates By journals.iucr.org Published On :: 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. Full Article text
mo Structures of hexamethyl-[1,1'-biphenyl]-4,4'-diammonium salts By journals.iucr.org Published On :: The structures of nine hexamethyl-[1,1'-biphenyl]-4,4'-diammonium (HMB) salts are described Full Article text
mo Coordination geometry flexibility driving supramolecular isomerism of Cu/Mo pillared-layer hybrid networks By journals.iucr.org Published On :: The hydrothermal synthesis and structural characterization of four novel 3D pillared-layer metal–organic frameworks are studied, revealing how the malleability of copper coordination geometries drives diverse supramolecular isomerism. The findings provide new insights into designing advanced hybrid materials with tailored properties, emphasizing the significant role of reaction conditions and metal ion flexibility in determining network topologies. Full Article text
mo Polymorphism of Pb5(PO4)3OHδ within the LK-99 mixture By journals.iucr.org Published On :: A new orthorhombic crystal Pb5(PO4)3OHδ of space-group symmetry Pnma significantly differs differing from the hexagonal apatite phases of Pb10(PO4)6O and Pb5(PO4)3OH. Full Article text
mo Seed layer formation by deposition of micro-crystallites on a revolving substrate: modeling of the effective linear elastic, piezoelectric, and dielectric coefficients By journals.iucr.org Published On :: 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. Full Article text
mo Selective Acceleration and Inhibition of Crystal Growth of Glass Carbamazepine by Low-Concentration Poly(ethylene oxide):Effects of Drug Polymorph By journals.iucr.org Published On :: Low-concentration poly(ethylene oxide) exhibit the polymorph-dependent effects on both the surface and bulk crystal growth of carbamazepine polymorphs. These polymorph-dependent effects of PEO were mainly attributed to the polymer enrichment at the interface and different crystal surface-polymer interactions. Full Article text
mo Crystal structure predictions for molecules with soft degrees of freedom using intermonomer force fields derived from first principles By journals.iucr.org Published On :: Full Article text
mo Atypical phase transition, twinning and ferroelastic domain structure in bis(ethylenediammonium) tetrabromozincate(II) bromide, [NH3(CH2)2NH3]2[ZnBr4]Br2 By journals.iucr.org Published On :: 2024-11-04 Single-crystal growth, differential thermal analysis (DTA), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X-ray structural studies and polarized microscopy observations of bis(ethylenediammonium) tetrabromozincate(II) bromide [NH3(CH2)2NH3]2[ZnBr4]Br2 are presented. A reversible phase transition is described. At room temperature, the complex crystallizes in the monoclinic system. In some cases, the single crystals are twinned into two or more large domains of ferroelastic type with domain walls in the (100) crystallographic plane. DTA and DTG measurements show chemical stability of the crystal up to ∼538 K. In the DSC studies, a reversible isostructural phase transition was revealed at ∼526/522 K on heating/cooling run, respectively. Optical observation on the heating run reveals that at the phase transition the plane of twinning (domain wall) does not disappear and additionally the appearance of a new domain structure of ferroelastic type with domain walls in the planes (101), (101), (100) and (001) is observed. The domain structure pattern is preserved after cooling to the room-temperature phase and the symmetry of this phase is unchanged. Full Article text
mo Morphological control for hollow rod crystals of a photochromic diarylethene on spherulites by surface properties of substrates By journals.iucr.org Published On :: 2024-10-31 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. Full Article text
mo From `crystallographic accuracy' to `thermodynamic accuracy': a redetermination of the crystal structure of calcium atorvastatin trihydrate (Lipitor®) By journals.iucr.org Published On :: 2024-10-08 With ever-improving quantum-mechanical computational methods, the accuracy requirements for experimental crystal structures increase. The crystal structure of calcium atorvastatin trihydrate, which has 56 degrees of freedom when determined with a real-space algorithm, was determined from powder diffraction data by Hodge et al. [Powder Diffr. (2020), 35, 136–143]. The crystal structure was a good fit to the experimental data, indicating that the electron density had been captured essentially correctly, but two independent quantum-mechanical calculations disagreed with the experimental structure and with each other. Using the same experimental data, the crystal structure was redetermined from scratch and it was shown that it can be reproduced within a root-mean-square Cartesian displacement of 0.1 Å by two independent quantum-mechanical calculations. The consequences for the calculated energies and solubilities are described. Full Article text
mo Crystal structure of the incommensurate modulated high-pressure phase of the potassium guaninate monohydrate By journals.iucr.org Published On :: 2024-10-08 The crystal structure of the incommensurate modulated phase of potassium guaninate monohydrate has been solved on the basis of high-pressure single-crystal X-ray diffraction data. The modulated structure was described as a `mosaic' sequence of three different local configurations of two neighbouring guaninate rings. In contrast to known examples of incommensurate modulated organic compounds, the modulation functions of all atoms are discontinuous. This is the first example of the experimental detection of an incommensurate modulated crystal structure that can be modelled using the special `soliton mode' modulation function proposed by Aramburu et al. [(1995), J. Phys. Condens. Matter, 7, 6187–6196]. Full Article text
mo Contrasting conformational behaviors of molecules XXXI and XXXII in the seventh blind test of crystal structure prediction By journals.iucr.org Published On :: 2024-10-14 Accurate modeling of conformational energies is key to the crystal structure prediction of conformational polymorphs. Focusing on molecules XXXI and XXXII from the seventh blind test of crystal structure prediction, this study employs various electronic structure methods up to the level of domain-local pair natural orbital coupled cluster singles and doubles with perturbative triples [DLPNO-CCSD(T1)] to benchmark the conformational energies and to assess their impact on the crystal energy landscapes. Molecule XXXI proves to be a relatively straightforward case, with the conformational energies from generalized gradient approximation (GGA) functional B86bPBE-XDM changing only modestly when using more advanced density functionals such as PBE0-D4, ωB97M-V, and revDSD-PBEP86-D4, dispersion-corrected second-order Møller–Plesset perturbation theory (SCS-MP2D), or DLPNO-CCSD(T1). In contrast, the conformational energies of molecule XXXII prove difficult to determine reliably, and variations in the computed conformational energies appreciably impact the crystal energy landscape. Even high-level methods such as revDSD-PBEP86-D4 and SCS-MP2D exhibit significant disagreements with the DLPNO-CCSD(T1) benchmarks for molecule XXXII, highlighting the difficulty of predicting conformational energies for complex, drug-like molecules. The best-converged predicted crystal energy landscape obtained here for molecule XXXII disagrees significantly with what has been inferred about the solid-form landscape experimentally. The identified limitations of the calculations are probably insufficient to account for the discrepancies between theory and experiment on molecule XXXII, and further investigation of the experimental solid-form landscape would be valuable. Finally, assessment of several semi-empirical methods finds r2SCAN-3c to be the most promising, with conformational energy accuracy intermediate between the GGA and hybrid functionals and a low computational cost. Full Article text
mo Assessment of the exchange-hole dipole moment dispersion correction for the energy ranking stage of the seventh crystal structure prediction blind test By journals.iucr.org Published On :: 2024-10-15 The seventh blind test of crystal structure prediction (CSP) methods substantially increased the level of complexity of the target compounds relative to the previous tests organized by the Cambridge Crystallographic Data Centre. In this work, the performance of density-functional methods is assessed using numerical atomic orbitals and the exchange-hole dipole moment dispersion correction (XDM) for the energy-ranking phase of the seventh blind test. Overall, excellent performance was seen for the two rigid molecules (XXVII, XXVIII) and for the organic salt (XXXIII). However, for the agrochemical (XXXI) and pharmaceutical (XXXII) targets, the experimental polymorphs were ranked fairly high in energy amongst the provided candidate structures and inclusion of thermal free-energy corrections from the lattice vibrations was found to be essential for compound XXXI. Based on these results, it is proposed that the importance of vibrational free-energy corrections increases with the number of rotatable bonds. Full Article text
mo Polymorph sampling with coupling to extended variables: enhanced sampling of polymorph energy landscapes and free energy perturbation of polymorph ensembles By journals.iucr.org Published On :: 2024-10-15 A novel approach to computationally enhance the sampling of molecular crystal structures is proposed and tested. This method is based on the use of extended variables coupled to a Monte Carlo based crystal polymorph generator. Inspired by the established technique of quasi-random sampling of polymorphs using the rigid molecule constraint, this approach represents molecular clusters as extended variables within a thermal reservoir. Polymorph unit-cell variables are generated using pseudo-random sampling. Within this framework, a harmonic coupling between the extended variables and polymorph configurations is established. The extended variables remain fixed during the inner loop dedicated to polymorph sampling, enforcing a stepwise propagation of the extended variables to maintain system exploration. The final processing step results in a polymorph energy landscape, where the raw structures sampled to create the extended variable trajectory are re-optimized without the thermal coupling term. The foundational principles of this approach are described and its effectiveness using both a Metropolis Monte Carlo type algorithm and modifications that incorporate replica exchange is demonstrated. A comparison is provided with pseudo-random sampling of polymorphs for the molecule coumarin. The choice to test a design of this algorithm as relevant for enhanced sampling of crystal structures was due to the obvious relation between molecular structure variables and corresponding crystal polymorphs as representative of the inherent vapor to crystal transitions that exist in nature. Additionally, it is shown that the trajectories of extended variables can be harnessed to extract fluctuation properties that can lead to valuable insights. A novel thermodynamic variable is introduced: the free energy difference between ensembles of Z' = 1 and Z' = 2 crystal polymorphs. Full Article text
mo Analytical models representing X-ray form factors of ions By journals.iucr.org Published On :: 2024-01-01 Parameters in analytical models for X-ray form factors of ions f0(s), based on the inverse Mott–Bethe formula involving a variable number of Gaussians, are determined for a wide range of published data sets {s, f0(s)}. The models reproduce the calculated form-factor values close to what is expected from a uniform statistical distribution with limits determined by their precision. For different ions associated with the same atom, the number of Gaussians in the models decreases with increasing net positive charge. Full Article text
mo Modelling dynamical 3D electron diffraction intensities. I. A scattering cluster algorithm By journals.iucr.org Published On :: 2024-01-25 Three-dimensional electron diffraction (3D-ED) is a powerful technique for crystallographic characterization of nanometre-sized crystals that are too small for X-ray diffraction. For accurate crystal structure refinement, however, it is important that the Bragg diffracted intensities are treated dynamically. Bloch wave simulations are often used in 3D-ED, but can be computationally expensive for large unit cell crystals due to the large number of diffracted beams. Proposed here is an alternative method, the `scattering cluster algorithm' (SCA), that replaces the eigen-decomposition operation in Bloch waves with a simpler matrix multiplication. The underlying principle of SCA is that the intensity of a given Bragg reflection is largely determined by intensity transfer (i.e. `scattering') from a cluster of neighbouring diffracted beams. However, the penalty for using matrix multiplication is that the sample must be divided into a series of thin slices and the diffracted beams calculated iteratively, similar to the multislice approach. Therefore, SCA is more suitable for thin specimens. The accuracy and speed of SCA are demonstrated on tri-isopropyl silane (TIPS) pentacene and rubrene, two exemplar organic materials with large unit cells. Full Article text
mo Modelling dynamical 3D electron diffraction intensities. II. The role of inelastic scattering By journals.iucr.org Published On :: 2024-01-25 The strong interaction of high-energy electrons with a crystal results in both dynamical elastic scattering and inelastic events, particularly phonon and plasmon excitation, which have relatively large cross sections. For accurate crystal structure refinement it is therefore important to uncover the impact of inelastic scattering on the Bragg beam intensities. Here a combined Bloch wave–Monte Carlo method is used to simulate phonon and plasmon scattering in crystals. The simulated thermal and plasmon diffuse scattering are consistent with experimental results. The simulations also confirm the empirical observation of a weaker unscattered beam intensity with increasing energy loss in the low-loss regime, while the Bragg-diffracted beam intensities do not change significantly. The beam intensities include the diffuse scattered background and have been normalized to adjust for the inelastic scattering cross section. It is speculated that the random azimuthal scattering angle during inelastic events transfers part of the unscattered beam intensity to the inner Bragg reflections. Inelastic scattering should not significantly influence crystal structure refinement, provided there are no artefacts from any background subtraction, since the relative intensity of the diffracted beams (which includes the diffuse scattering) remains approximately constant in the low energy loss regime. Full Article text
mo Automated selection of nanoparticle models for small-angle X-ray scattering data analysis using machine learning By journals.iucr.org Published On :: 2024-02-29 Small-angle X-ray scattering (SAXS) is widely used to analyze the shape and size of nanoparticles in solution. A multitude of models, describing the SAXS intensity resulting from nanoparticles of various shapes, have been developed by the scientific community and are used for data analysis. Choosing the optimal model is a crucial step in data analysis, which can be difficult and time-consuming, especially for non-expert users. An algorithm is proposed, based on machine learning, representation learning and SAXS-specific preprocessing methods, which instantly selects the nanoparticle model best suited to describe SAXS data. The different algorithms compared are trained and evaluated on a simulated database. This database includes 75 000 scattering spectra from nine nanoparticle models, and realistically simulates two distinct device configurations. It will be made freely available to serve as a basis of comparison for future work. Deploying a universal solution for automatic nanoparticle model selection is a challenge made more difficult by the diversity of SAXS instruments and their flexible settings. The poor transferability of classification rules learned on one device configuration to another is highlighted. It is shown that training on several device configurations enables the algorithm to be generalized, without degrading performance compared with configuration-specific training. Finally, the classification algorithm is evaluated on a real data set obtained by performing SAXS experiments on nanoparticles for each of the instrumental configurations, which have been characterized by transmission electron microscopy. This data set, although very limited, allows estimation of the transferability of the classification rules learned on simulated data to real data. Full Article text
mo Permissible domain walls in monoclinic ferroelectrics. Part II. The case of MC phases By journals.iucr.org Published On :: 2024-04-29 Monoclinic ferroelectric phases are prevalent in various functional materials, most notably mixed-ion perovskite oxides. These phases can manifest as regularly ordered long-range crystallographic structures or as macroscopic averages of the self-assembled tetragonal/rhombohedral nanodomains. The structural and physical properties of monoclinic ferroelectric phases play a pivotal role when exploring the interplay between ferroelectricity, ferroelasticity, giant piezoelectricity and multiferroicity in crystals, ceramics and epitaxial thin films. However, the complex nature of this subject presents challenges, particularly in deciphering the microstructures of monoclinic domains. In Paper I [Biran & Gorfman (2024). Acta Cryst. A80, 112–128] the geometrical principles governing the connection of domain microstructures formed by pairing MAB type monoclinic domains were elucidated. Specifically, a catalog was established of `permissible domain walls', where `permissible', as originally introduced by Fousek & Janovec [J. Appl. Phys. (1969), 40, 135–142], denotes a mismatch-free connection between two monoclinic domains along the corresponding domain wall. The present article continues the prior work by elaborating on the formalisms of permissible domain walls to describe domain microstructures formed by pairing the MC type monoclinic domains. Similarly to Paper I, 84 permissible domain walls are presented for MC type domains. Each permissible domain wall is characterized by Miller indices, the transformation matrix between the crystallographic basis vectors of the domains and, crucially, the expected separation of Bragg peaks diffracted from the matched pair of domains. All these parameters are provided in an analytical form for easy and intuitive interpretation of the results. Additionally, 2D illustrations are provided for selected instances of permissible domain walls. The findings can prove valuable for various domain-related calculations, investigations involving X-ray diffraction for domain analysis and the description of domain-related physical properties. Full Article text
mo Structure of the outer membrane porin OmpW from the pervasive pathogen Klebsiella pneumoniae By journals.iucr.org Published On :: 2024-01-01 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. Full Article text
mo Crystal structure of the RNA-recognition motif of Drosophila melanogaster tRNA (uracil-5-)-methyltransferase homolog A By journals.iucr.org Published On :: 2024-01-25 Human tRNA (uracil-5-)-methyltransferase 2 homolog A (TRMT2A) is the dedicated enzyme for the methylation of uridine 54 in transfer RNA (tRNA). Human TRMT2A has also been described as a modifier of polyglutamine (polyQ)-derived neuronal toxicity. The corresponding human polyQ pathologies include Huntington's disease and constitute a family of devastating neurodegenerative diseases. A polyQ tract in the corresponding disease-linked protein causes neuronal death and symptoms such as impaired motor function, as well as cognitive impairment. In polyQ disease models, silencing of TRMT2A reduced polyQ-associated cell death and polyQ protein aggregation, suggesting this protein as a valid drug target against this class of disorders. In this paper, the 1.6 Å resolution crystal structure of the RNA-recognition motif (RRM) from Drosophila melanogaster, which is a homolog of human TRMT2A, is described and analysed. Full Article text
mo Expression, purification and crystallization of the photosensory module of phytochrome B (phyB) from Sorghum bicolor By journals.iucr.org Published On :: 2024-02-20 Sorghum, a short-day tropical plant, has been adapted for temperate grain production, in particular through the selection of variants at the MATURITY loci (Ma1–Ma6) that reduce photoperiod sensitivity. Ma3 encodes phytochrome B (phyB), a red/far-red photochromic biliprotein photoreceptor. The multi-domain gene product, comprising 1178 amino acids, autocatalytically binds the phytochromobilin chromophore to form the photoactive holophytochrome (Sb.phyB). This study describes the development of an efficient heterologous overproduction system which allows the production of large quantities of various holoprotein constructs, along with purification and crystallization procedures. Crystals of the Pr (red-light-absorbing) forms of NPGP, PGP and PG (residues 1–655, 114–655 and 114–458, respectively), each C-terminally tagged with His6, were successfully produced. While NPGP crystals did not diffract, those of PGP and PG diffracted to 6 and 2.1 Å resolution, respectively. Moving the tag to the N-terminus and replacing phytochromobilin with phycocyanobilin as the ligand produced PG crystals that diffracted to 1.8 Å resolution. These results demonstrate that the diffraction quality of challenging protein crystals can be improved by removing flexible regions, shifting fusion tags and altering small-molecule ligands. Full Article text