late Kyodo: S. Korea, US, Japan Coordinating Trilateral Summit during APEC By world.kbs.co.kr Published On :: Tue, 12 Nov 2024 10:32:36 +0900 [International] : South Korea, the United States and Japan are reportedly coordinating plans for a trilateral summit on the sidelines of the Asia-Pacific Economic Cooperation(APEC) summit, set for this week in Peru. Quoting a Japanese government official, Japan’s Kyodo News said Monday that coordination is underway to hold ...[more...] Full Article International
late S. Korea, US, Japan to Hold Second Trilateral Freedom Edge Exercise This Week By world.kbs.co.kr Published On :: Wed, 13 Nov 2024 10:01:47 +0900 [International] : South Korea, the United States and Japan are set to hold their trilateral multidomain Freedom Edge exercise this week. According to South Korea’s Joint Chiefs of Staff(JCS), this year’s second Freedom Edge exercise runs Wednesday to Friday in international waters south of Jeju Island. The three ...[more...] Full Article International
late 8 Most Densely Populated Cities in the World By history.howstuffworks.com Published On :: Fri, 08 Nov 2024 10:15:03 -0500 Statistically, over half of the people reading this article live in a city, with a higher population density than rural or suburban areas. For instance, New York City has nearly 27,000 people crammed into each square mile (2.6 square km) of land. Full Article
late 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
late 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
late X-ray phase-contrast tomography of cells manipulated with an optical stretcher By journals.iucr.org Published On :: 2024-06-11 X-rays can penetrate deeply into biological cells and thus allow for examination of their internal structures with high spatial resolution. In this study, X-ray phase-contrast imaging and tomography is combined with an X-ray-compatible optical stretcher and microfluidic sample delivery. Using this setup, individual cells can be kept in suspension while they are examined with the X-ray beam at a synchrotron. From the recorded holograms, 2D phase shift images that are proportional to the projected local electron density of the investigated cell can be calculated. From the tomographic reconstruction of multiple such projections the 3D electron density can be obtained. The cells can thus be studied in a hydrated or even living state, thus avoiding artifacts from freezing, drying or embedding, and can in principle also be subjected to different sample environments or mechanical strains. This combination of techniques is applied to living as well as fixed and stained NIH3T3 mouse fibroblasts and the effect of the beam energy on the phase shifts is investigated. Furthermore, a 3D algebraic reconstruction scheme and a dedicated mathematical description is used to follow the motion of the trapped cells in the optical stretcher for multiple rotations. Full Article text
late Structure and absolute configuration of natural fungal product beauveriolide I, isolated from Cordyceps javanica, determined by 3D electron diffraction By journals.iucr.org Published On :: 2024-02-27 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. Full Article text
late Formation of extended polyiodides at large cation templates By journals.iucr.org Published On :: 2024-05-13 By studying the structures of (μ-1,4,10,13-tetrathia-7,16-diazacyclooctadecane)bis[iodidopalladium(II)] diiodide penta(diiodine), [Pd2I2(C12H26N2S4)](I)2·5I2 or [Pd2I2([18]aneN2S4)](I)2·(I2)5, and 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane triiodide iodide hemipenta(diiodine) dichloromethane monosolvate, C18H38N2O62+·I3−·I−·2.5I2·CH2Cl2 or [H2([2.2.2]cryptand)](I3)(I)(I2)2.5·CH2Cl2, we confirm the structural variety of extended polyiodides achievable upon changing the shape, charge and dimensions of the cation template, by altering the synthetic strategy adopted and/or the experimental conditions. Although it is still often difficult to characterize discrete [I2m+n]n− polyiodides higher than I3− on the basis of structural parameters, such as I—I bond distances, FT–Raman spectroscopy appears to identify them as aggregates of I2, I− and (symmetric or slightly asymmetric) I3− building blocks linked by I⋯I interactions of varying strengths. However, because FT–Raman spectroscopy carries no information about the topological features of extended polyiodides, the two techniques should therefore be applied in combination to enhance the analysis of this kind of compounds. Full Article text
late TAAM refinement on high-resolution experimental and simulated 3D ED/MicroED data for organic molecules By journals.iucr.org Published On :: 2024-06-27 3D electron diffraction (3D ED), or microcrystal electron diffraction (MicroED), has become an alternative technique for determining the high-resolution crystal structures of compounds from sub-micron-sized crystals. Here, we considered l-alanine, α-glycine and urea, which are known to form good-quality crystals, and collected high-resolution 3D ED data on our in-house TEM instrument. In this study, we present a comparison of independent atom model (IAM) and transferable aspherical atom model (TAAM) kinematical refinement against experimental and simulated data. TAAM refinement on both experimental and simulated data clearly improves the model fitting statistics (R factors and residual electrostatic potential) compared to IAM refinement. This shows that TAAM better represents the experimental electrostatic potential of organic crystals than IAM. Furthermore, we compared the geometrical parameters and atomic displacement parameters (ADPs) resulting from the experimental refinements with the simulated refinements, with the periodic density functional theory (DFT) calculations and with published X-ray and neutron crystal structures. The TAAM refinements on the 3D ED data did not improve the accuracy of the bond lengths between the non-H atoms. The experimental 3D ED data provided more accurate H-atom positions than the IAM refinements on the X-ray diffraction data. The IAM refinements against 3D ED data had a tendency to lead to slightly longer X—H bond lengths than TAAM, but the difference was statistically insignificant. Atomic displacement parameters were too large by tens of percent for l-alanine and α-glycine. Most probably, other unmodelled effects were causing this behaviour, such as radiation damage or dynamical scattering. Full Article text
late Efficient in situ screening of and data collection from microcrystals in crystallization plates By journals.iucr.org Published On :: 2024-03-15 A considerable bottleneck in serial crystallography at XFEL and synchrotron sources is the efficient production of large quantities of homogenous, well diffracting microcrystals. Efficient high-throughput screening of batch-grown microcrystals and the determination of ground-state structures from different conditions is thus of considerable value in the early stages of a project. Here, a highly sample-efficient methodology to measure serial crystallography data from microcrystals by raster scanning within standard in situ 96-well crystallization plates is described. Structures were determined from very small quantities of microcrystal suspension and the results were compared with those from other sample-delivery methods. The analysis of a two-dimensional batch crystallization screen using this method is also described as a useful guide for further optimization and the selection of appropriate conditions for scaling up microcrystallization. Full Article text
late STOPGAP: an open-source package for template matching, subtomogram alignment and classification By journals.iucr.org Published On :: 2024-04-12 Cryo-electron tomography (cryo-ET) enables molecular-resolution 3D imaging of complex biological specimens such as viral particles, cellular sections and, in some cases, whole cells. This enables the structural characterization of molecules in their near-native environments, without the need for purification or separation, thereby preserving biological information such as conformational states and spatial relationships between different molecular species. Subtomogram averaging is an image-processing workflow that allows users to leverage cryo-ET data to identify and localize target molecules, determine high-resolution structures of repeating molecular species and classify different conformational states. Here, STOPGAP, an open-source package for subtomogram averaging that is designed to provide users with fine control over each of these steps, is described. In providing detailed descriptions of the image-processing algorithms that STOPGAP uses, this manuscript is also intended to serve as a technical resource to users as well as for further community-driven software development. Full Article text
late What shapes template-matching performance in cryogenic electron tomography in situ? By journals.iucr.org Published On :: 2024-05-28 The detection of specific biological macromolecules in cryogenic electron tomography data is frequently approached by applying cross-correlation-based 3D template matching. To reduce computational cost and noise, high binning is used to aggregate voxels before template matching. This remains a prevalent practice in both practical applications and methods development. Here, the relation between template size, shape and angular sampling is systematically evaluated to identify ribosomes in a ground-truth annotated data set. It is shown that at the commonly used binning, a detailed subtomogram average, a sphere and a heart emoji result in near-identical performance. These findings indicate that with current template-matching practices macromolecules can only be detected with high precision if their shape and size are sufficiently different from the background. Using theoretical considerations, the experimental results are rationalized and it is discussed why primarily low-frequency information remains at high binning and that template matching fails to be accurate because similarly shaped and sized macromolecules have similar low-frequency spectra. These challenges are discussed and potential enhancements for future template-matching methodologies are proposed. Full Article text
late Structural analysis of a ligand-triggered intermolecular disulfide switch in a major latex protein from opium poppy By journals.iucr.org Published On :: 2024-08-29 Several proteins from plant pathogenesis-related family 10 (PR10) are highly abundant in the latex of opium poppy and have recently been shown to play diverse and important roles in the biosynthesis of benzylisoquinoline alkaloids (BIAs). The recent determination of the first crystal structures of PR10-10 showed how large conformational changes in a surface loop and adjacent β-strand are coupled to the binding of BIA compounds to the central hydrophobic binding pocket. A more detailed analysis of these conformational changes is now reported to further clarify how ligand binding is coupled to the formation and cleavage of an intermolecular disulfide bond that is only sterically allowed when the BIA binding pocket is empty. To decouple ligand binding from disulfide-bond formation, each of the two highly conserved cysteine residues (Cys59 and Cys155) in PR10-10 was replaced with serine using site-directed mutagenesis. Crystal structures of the Cys59Ser mutant were determined in the presence of papaverine and in the absence of exogenous BIA compounds. A crystal structure of the Cys155Ser mutant was also determined in the absence of exogenous BIA compounds. All three of these crystal structures reveal conformations similar to that of wild-type PR10-10 with bound BIA compounds. In the absence of exogenous BIA compounds, the Cys59Ser and Cys155Ser mutants appear to bind an unidentified ligand or mixture of ligands that was presumably introduced during expression of the proteins in Escherichia coli. The analysis of conformational changes triggered by the binding of BIA compounds suggests a molecular mechanism coupling ligand binding to the disruption of an intermolecular disulfide bond. This mechanism may be involved in the regulation of biosynthetic reactions in plants and possibly other organisms. Full Article text
late In situ serial crystallography facilitates 96-well plate structural analysis at low symmetry By journals.iucr.org Published On :: 2024-07-15 The advent of serial crystallography has rejuvenated and popularized room-temperature X-ray crystal structure determination. Structures determined at physiological temperature reveal protein flexibility and dynamics. In addition, challenging samples (e.g. large complexes, membrane proteins and viruses) form fragile crystals that are often difficult to harvest for cryo-crystallography. Moreover, a typical serial crystallography experiment requires a large number of microcrystals, mainly achievable through batch crystallization. Many medically relevant samples are expressed in mammalian cell lines, producing a meager quantity of protein that is incompatible with batch crystallization. This can limit the scope of serial crystallography approaches. Direct in situ data collection from a 96-well crystallization plate enables not only the identification of the best diffracting crystallization condition but also the possibility for structure determination under ambient conditions. Here, we describe an in situ serial crystallography (iSX) approach, facilitating direct measurement from crystallization plates mounted on a rapidly exchangeable universal plate holder deployed at a microfocus beamline, ID23-2, at the European Synchrotron Radiation Facility. We applied our iSX approach on a challenging project, autotaxin, a therapeutic target expressed in a stable human cell line, to determine the structure in the lowest-symmetry P1 space group at 3.0 Å resolution. Our in situ data collection strategy provided a complete dataset for structure determination while screening various crystallization conditions. Our data analysis reveals that the iSX approach is highly efficient at a microfocus beamline, improving throughput and demonstrating how crystallization plates can be routinely used as an alternative method of presenting samples for serial crystallography experiments at synchrotrons. Full Article text
late Crystal structure of a bacterial photoactivated adenylate cyclase determined by serial femtosecond and serial synchrotron crystallography By journals.iucr.org Published On :: 2024-10-29 OaPAC is a recently discovered blue-light-using flavin adenosine dinucleotide (BLUF) photoactivated adenylate cyclase from the cyanobacterium Oscillatoria acuminata that uses adenosine triphosphate and translates the light signal into the production of cyclic adenosine monophosphate. Here, we report crystal structures of the enzyme in the absence of its natural substrate determined from room-temperature serial crystallography data collected at both an X-ray free-electron laser and a synchrotron, and we compare these structures with cryo-macromolecular crystallography structures obtained at a synchrotron by us and others. These results reveal slight differences in the structure of the enzyme due to data collection at different temperatures and X-ray sources. We further investigate the effect of the Y6W mutation in the BLUF domain, a mutation which results in a rearrangement of the hydrogen-bond network around the flavin and a notable rotation of the side chain of the critical Gln48 residue. These studies pave the way for picosecond–millisecond time-resolved serial crystallography experiments at X-ray free-electron lasers and synchrotrons in order to determine the early structural intermediates and correlate them with the well studied picosecond–millisecond spectroscopic intermediates. Full Article text
late Three-dimensional electron diffraction on clinkers: the belite α'H incommensurate modulated structure By journals.iucr.org Published On :: 2024-03-06 Traditional X-ray methods are extensively applied to commercial cement samples in order to determine their physical and chemical properties. Powder patterns are routinely used to quantify the composition of these phase mixtures, but structure determination becomes difficult because of reflection overlapping caused by the high number of different crystal structures. The fast-growing 3D electron diffraction technique and its related automated acquisition protocols arise as a potentially very interesting tool for the cement industry, since they enable the fast and systematic acquisition of diffraction data from individual particles. In this context, electron diffraction has been used in the investigation of the different crystalline phases present in various commercial clinkers for cement. Automated data collection procedures and subsequent data processing have enabled the structural characterization of the different crystal structures from which the α'H polymorph of Ca2SiO4 (belite) exhibited satellite reflections. Its average crystal structure has been known since 1971 and satellite reflections have been reported previously, yet the modulation was never fully described by means of the superspace formalism. Here, the incommensurately modulated structure is solved and refined using harmonic and crenel functions in the superspace group Pnma(α00)0ss, showing the potential of 3D electron diffraction for systematic crystallographic characterizations of cement. A full description of the different belite polymorphs is provided considering this modulated structure. Full Article text
late Crystal structure of S-n-octyl 3-(1-phenylethylidene)dithiocarbazate and of its bis-chelated nickel(II) complex By journals.iucr.org Published On :: 2023-11-14 The nitrogen–sulfur Schiff base proligand S-n-octyl 3-(1-phenylethylidene)dithiocarbazate, C17H26N2S2 (HL), was prepared by reaction of S-octyl dithiocarbamate with acetophenone. Treatment of HL with nickel acetate yielded the complex bis[S-n-octyl 3-(1-phenylethylidene)dithiocarbazato]nickel(II), [Ni(C17H25N2S2)2] (NiL2), which was shown to adopt a tetrahedrally distorted cis-square-planar coordination geometry, with the NiSN planes of the two ligands forming a dihedral angle of 21.66 (6)°. Changes in the geometry of the L ligand upon chelation of Ni2+ are described, involving a ca 180° rotation around the N(azomethine)—C(thiolate) bond. Full Article text
late Synthesis and crystal structures of two related Co and Mn complexes: a celebration of collaboration between the universities of Dakar and Southampton By journals.iucr.org Published On :: 2023-11-16 We report the synthesis and structures of two transition-metal complexes involving 2-(2-hydroxyphenyl)benzimidazole (2hpbi – a ligand of interest for its photoluminescent applications), with cobalt, namely, bis[μ-2-(1H-1,3-benzodiazol-2-yl)phenolato]bis[ethanol(thiocyanato)cobalt(II)], [Co2(C13H9N2O)2(NCS)2(C2H6O)2], (1), and manganese, namely, bis[μ-2-(1H-1,3-benzodiazol-2-yl)phenolato]bis{[2-(1H-1,3-benzodiazol-2-yl)phenolato](thiocyanato)manganese(III)} dihydrate, [Mn2(C13H9N2O)4(NCS)2]·2H2O, (2). These structures are two recent examples of a fruitful collaboration between researchers at the Laboratoire de Chimie de Coordination Organique/Organic Coordination Chemistry Laboratory (LCCO), University of Dakar, Senegal and the National Crystallography Service (NCS), School of Chemistry, University Southampton, UK. This productive partnership was forged through meeting at Pan-African Conferences on Crystallography and quickly grew as the plans for the AfCA (African Crystallographic Association) developed. This article therefore also showcases this productive partnership, in celebration of the IUCr's 75 year anniversary and the recent inclusion of AfCA as a Regional Associate of the IUCr. Full Article text
late An octanuclear nickel(II) pyrazolate cluster with a cubic Ni8 core and its methyl- and n-octyl-functionalized derivatives By journals.iucr.org Published On :: 2023-11-30 The molecular and crystal structure of a discrete [Ni8(μ4-OH)6(μ-4-Rpz)12]2− (R = H; pz = pyrazolate anion, C3H3N2−) cluster with an unprecedented, perfectly cubic arrangement of its eight Ni centers is reported, along with its lower-symmetry alkyl-functionalized (R = methyl and n-octyl) derivatives. Crystals of the latter two were obtained with two identical counter-ions (Bu4N+), whereas the crystal of the complex with the parent pyrazole ligand has one Me4N+ and one Bu4N+ counter-ion. The methyl derivative incorporates 1,2-dichloroethane solvent molecules in its crystal structure, whereas the other two are solvent-free. The compounds are tetrabutylazanium tetramethylazanium hexa-μ4-hydroxido-dodeca-μ2-pyrazolato-hexahedro-octanickel, (C16H36N)(C4H12N)[Ni8(C3H3N2)12(OH)6] or (Bu4N)(Me4N)[Ni8(μ4-OH)6(μ-pz)12] (1), bis(tetrabutylazanium) hexa-μ4-hydroxido-dodeca-μ2-(4-methylpyrazolato)-hexahedro-octanickel 1,2-dichloroethane 7.196-solvate, (C16H36N)2[Ni8(C4H5N2)12(OH)6]·7.196C2H4Cl2 or (Bu4N)2[Ni8(μ4-OH)6(μ-4-Mepz)12]·7.196(ClCH2CH2Cl) (2), and bis(tetrabutylazanium) hexa-μ4-hydroxido-dodeca-μ2-(4-octylpyrazolato)-hexahedro-octanickel, (C16H36N)2[Ni8(C11H19N2)12(OH)6] or (Bu4N)2[Ni8(μ4-OH)6(μ-4-nOctpz)12] (3). All counter-ions are disordered (with the exception of one Bu4N+ in 3). Some of the octyl chains of 3 (the crystal is twinned by non-merohedry) are also disordered. Various structural features are discussed and contrasted with those of other known [Ni8(μ4-OH)6(μ-4-Rpz)12]2− complexes, including extended three-dimensional metal–organic frameworks. In all three structures, the Ni8 units are lined up in columns. Full Article text
late Crystal structure of a water oxidation catalyst solvate with composition (NH4)2[FeIV(L-6H)]·3CH3COOH (L = clathrochelate ligand) By journals.iucr.org Published On :: 2024-01-01 The synthetic availability of molecular water oxidation catalysts containing high-valent ions of 3d metals in the active site is a prerequisite to enabling photo- and electrochemical water splitting on a large scale. Herein, the synthesis and crystal structure of diammonium {μ-1,3,4,7,8,10,12,13,16,17,19,22-dodecaazatetracyclo[8.8.4.13,17.18,12]tetracosane-5,6,14,15,20,21-hexaonato}ferrate(IV) acetic acid trisolvate, (NH4)2[FeIV(C12H12N12O6)]·3CH3COOH or (NH4)2[FeIV(L–6H)]·3CH3COOH is reported. The FeIV ion is encapsulated by the macropolycyclic ligand, which can be described as a dodeca-aza-quadricyclic cage with two capping triazacyclohexane fragments making three five- and six six-membered alternating chelate rings with the central FeIV ion. The local coordination environment of FeIV is formed by six deprotonated hydrazide nitrogen atoms, which stabilize the unusual oxidation state. The FeIV ion lies on a twofold rotation axis (multiplicity 4, Wyckoff letter e) of the space group C2/c. Its coordination geometry is intermediate between a trigonal prism (distortion angle φ = 0°) and an antiprism (φ = 60°) with φ = 31.1°. The Fe—N bond lengths lie in the range 1.9376 (13)–1.9617 (13) Å, as expected for tetravalent iron. Structure analysis revealed that three acetic acid molecules additionally co-crystallize per one iron(IV) complex, and one of them is positionally disordered over four positions. In the crystal structure, the ammonium cations, complex dianions and acetic acid molecules are interconnected by an intricate system of hydrogen bonds, mainly via the oxamide oxygen atoms acting as acceptors. Full Article text
late Crystal structure of hexachlorothallate within a caesium chloride–phosphotungstate lattice Cs9(TlCl6)(PW12O40)2·9CsCl By journals.iucr.org Published On :: 2024-06-14 Crystal formation of caesium thallium chloride phosphotungstates, Cs9(TlCl6)(PW12O40)2·9CsCl showcases the ability to capture and crystallize octahedral complexes via the use of polyoxometalates (POMs). The large number of caesium chlorides allows for the POM [α-PW12O40]3− to arrange itself in a cubic close-packing lattice extended framework, in which the voids created enable the capture of the [TlCl6]3− complex. Full Article text
late POMFinder: identifying polyoxometallate cluster structures from pair distribution function data using explainable machine learning By journals.iucr.org Published On :: 2024-02-01 Characterization of a material structure with pair distribution function (PDF) analysis typically involves refining a structure model against an experimental data set, but finding or constructing a suitable atomic model for PDF modelling can be an extremely labour-intensive task, requiring carefully browsing through large numbers of possible models. Presented here is POMFinder, a machine learning (ML) classifier that rapidly screens a database of structures, here polyoxometallate (POM) clusters, to identify candidate structures for PDF data modelling. The approach is shown to identify suitable POMs from experimental data, including in situ data collected with fast acquisition times. This automated approach has significant potential for identifying suitable models for structure refinement to extract quantitative structural parameters in materials chemistry research. POMFinder is open source and user friendly, making it accessible to those without prior ML knowledge. It is also demonstrated that POMFinder offers a promising modelling framework for combined modelling of multiple scattering techniques. Full Article text
late Refinement of X-ray and electron diffraction crystal structures using analytical Fourier transforms of Slater-type atomic wavefunctions in Olex2 By journals.iucr.org Published On :: 2024-02-01 An implementation of Slater-type spherical scattering factors for X-ray and electron diffraction for elements in the range Z = 1–103 is presented within the software Olex2. Both high- and low-angle Fourier behaviour of atomic electron density and electrostatic potential can thus be addressed, in contrast to the limited flexibility of the four Gaussian plus constant descriptions which are currently the most widely used method for calculating atomic scattering factors during refinement. The implementation presented here accommodates the increasing complexity of the electronic structure of heavier elements by using complete atomic wavefunctions without any interpolation between precalculated tables or intermediate fitting functions. Atomic wavefunctions for singly charged ions are implemented and made accessible, and these show drastic changes in electron diffraction scattering factors compared with the neutral atom. A comparison between the two different spherical models of neutral atoms is presented as an example for four different kinds of X-ray and two electron diffraction structures, and comparisons of refinement results using the existing diffraction data are discussed. A systematic but slight improvement in R values and residual densities can be observed when using the new scattering factors, and this is discussed relative to effects on the atomic displacement parameters and atomic positions, which are prominent near the heavier elements in a structure. Full Article text
late Design and fabrication of 3D-printed in situ crystallization plates for probing microcrystals in an external electric field By journals.iucr.org Published On :: 2024-04-15 X-ray crystallography is an established tool to probe the structure of macromolecules with atomic resolution. Compared with alternative techniques such as single-particle cryo-electron microscopy and micro-electron diffraction, X-ray crystallography is uniquely suited to room-temperature studies and for obtaining a detailed picture of macromolecules subjected to an external electric field (EEF). The impact of an EEF on proteins has been extensively explored through single-crystal X-ray crystallography, which works well with larger high-quality protein crystals. This article introduces a novel design for a 3D-printed in situ crystallization plate that serves a dual purpose: fostering crystal growth and allowing the concurrent examination of the effects of an EEF on crystals of varying sizes. The plate's compatibility with established X-ray crystallography techniques is evaluated. Full Article text
late Towards dynamically configured databases for CIFs: the new modulated structures open database at the Bilbao Crystallographic Server By journals.iucr.org Published On :: 2024-09-17 This article presents a web-based framework to build a database without in-depth programming knowledge given a set of CIF dictionaries and a collection of CIFs. The framework consists of two main elements: the public site that displays the information contained in the CIFs in an ordered manner, and the restricted administrative site which defines how that information is stored, processed and, eventually, displayed. Thus, the web application allows users to easily explore, filter and access the data, download the original CIFs, and visualize the structures via JSmol. The modulated structures open database B-IncStrDB, the official International Union of Crystallography repository for this type of material and available through the Bilbao Crystallographic Server, has been re-implemented following the proposed framework. Full Article text
late A study of structural effects on the focusing and imaging performance of hard X-rays with 20–30 nm zone plates By journals.iucr.org Published On :: 2024-10-28 Hard X-ray microscopes with 20–30 nm spatial resolution ranges are an advanced tool for the inspection of materials at the nanoscale. However, the limited efficiency of the focusing optics, for example, a Fresnel zone plate (ZP) lens, can significantly reduce the power of a nanoprobe. Despite several reports on ZP lenses that focus hard X-rays with 20 nm resolution – mainly constructed by zone-doubling techniques – a systematic investigation into the limiting factors has not been reported. We report the structural effects on the focusing and imaging efficiency of 20–30 nm-resolution ZPs, employing a modified beam-propagation method. The zone width and the duty cycle (zone width/ring pitch) were optimized to achieve maximum efficiency, and a comparative analysis of the zone materials was conducted. The optimized zone structures were used in the fabrication of Pt-hydrogen silsesquioxane (HSQ) ZPs. The highest focusing efficiency of the Pt-HSQ-ZP with a resolution of 30 nm was 10% at 7 keV and >5% in the range 6–10 keV, whereas the highest efficiency of the Pt-HSQ-ZP with a resolution of 20 nm was realized at 7 keV with an efficiency of 7.6%. Optical characterization conducted at X-ray beamlines demonstrated significant enhancement of the focusing and imaging efficiency in a broader range of hard X-rays from 5 keV to 10 keV, demonstrating the potential application in hard X-ray focusing and imaging. Full Article text
late Periodic graphs with coincident edges: folding-ladder and related graphs By journals.iucr.org Published On :: We explore a special class of periodic graphs, ladder graphs, whose edges can coincide when embedded vertices are moved. Many of these exhibit additional non-crystallographic graph symmetries. Full Article text
late EPA announces Catawba County to again be "in attainment for particulate matter (PM 2.5) By www.catawbacountync.gov Published On :: Mon, 21 Nov 2011 17:55:00 EST The United States Environmental Planning Agency (USEPA) has announced that Catawba County will be classified as �attainment� from its current �nonattainment� designation for Particulate Matter 2.5 (PM 2.5) on December 19, 2011. PM 2.5 (fine particle pollution) refers to tiny particles of droplets in the air that are two and one half microns or less in width. Two and one half microns is about thirty times smaller than the width of a human hair. Full Article News Release FYI Public Notice
late Adults Need to Increase Intake of Folate - Some Women Should Take More By Published On :: Tue, 07 Apr 1998 05:00:00 GMT Women who might become pregnant need 400 micrograms of folic acid per day to reduce their risk of having a child with neural tube defects, according to the latest report on Dietary Reference Intakes (DRIs) from the Institute of Medicine. Full Article
late Medication Errors Injure 1.5 Million People and Cost Billions of Dollars Annually - Report Offers Comprehensive Strategies for Reducing Drug-Related Mistakes By Published On :: Thu, 20 Jul 2006 05:00:00 GMT Medication errors are among the most common medical errors, harming at least 1.5 million people every year, says a new report from the Institute of Medicine of the National Academies. Full Article
late Daniel Kahnemans Thinking, Fast and Slow Wins Best Book Award From Academies - Milwaukee Journal Sentinel, Slate Magazine, and WGBH/NOVA Also Take Top Prizes in Awards 10th Year By Published On :: Thu, 13 Sep 2012 05:00:00 GMT Recipients of the 10th annual Communication Awards were announced today by the National Academy of Sciences, National Academy of Engineering, and Institute of Medicine. Full Article
late Latest and Final Biennial Review of Health Problems That May Be Linked to Agent Orange Exposure During Vietnam War By Published On :: Thu, 10 Mar 2016 06:00:00 GMT The latest and final in a series of congressionally mandated biennial reviews of the evidence of health problems that may be linked to exposure to Agent Orange and other herbicides used during the Vietnam War changed the categorization of health outcomes for bladder cancer, hypothyroidism, and spina bifida and clarified the breadth of the previous finding for Parkinson’s disease. Full Article
late General Support for Science Does Not Always Correlate With Attitudes Toward Specific Science Issues, Says New Report By Published On :: Tue, 09 Aug 2016 05:00:00 GMT U.S. adults perform comparably to adults in other economically developed countries on most measures of science knowledge and support science in general, says a new report from the National Academies of Sciences, Engineering, and Medicine. Full Article
late Policies Governing Dual-Use Research in the Life Sciences Are Fragmented - Most Scientists Have Little Awareness of Issues Related to Biosecurity By Published On :: Thu, 14 Sep 2017 05:00:00 GMT A new report from the National Academies of Sciences, Engineering, and Medicine examines policies and practices governing dual-use research in the life sciences – research that could potentially be misused to cause harm – and its findings identify multiple shortcomings. Full Article
late Assessment of Work-Related Functional Abilities Is Important In Disability Determination By Published On :: Thu, 09 May 2019 04:00:00 GMT Assessments of a person’s ability to function at work provide important information for disability determinations, and many validated tests are available to assess work-related physical and mental functions. Full Article
late Federal Agencies Should Adopt Uniform Framework for Quantifying Disaster-Related Deaths, Illness, Says New Report By Published On :: Wed, 09 Sep 2020 04:00:00 GMT To more accurately quantify disaster-related deaths, injuries, and illnesses, the Federal Emergency Management Agency and other agencies supporting disaster response should adopt a uniform national framework of data collection approaches and methods for distinguishing direct from indirect disaster deaths, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine. Full Article
late Can Manipulating the Gut Microbiome Slow Age-Related Inflammation? By Published On :: Wed, 04 Nov 2020 05:00:00 GMT There are the telltale signs of aging — a few more wrinkles, graying hair, and changes in posture. Other changes are less obvious. Aging-related changes also occur within the gut microbiome — a collection of bacteria, viruses, and fungi that live in your digestive tract. Full Article
late Although Childhood Cancer Survival Rates Have Improved, Survivors Face Disability-Related Challenges Throughout Adulthood By Published On :: Wed, 09 Dec 2020 05:00:00 GMT Survivors of childhood cancer have an increased risk of experiencing disabling conditions, both from the cancer itself and from the effects of treatment, says a new report from the National Academies of Sciences, Engineering, and Medicine. Full Article
late NAS, NAE, and NAM Presidents Congratulate President Biden and Vice President Harris on Their Inauguration By Published On :: Wed, 20 Jan 2021 05:00:00 GMT We congratulate President Joe Biden and Vice President Kamala Harris on this historic day, and we are grateful for their lifelong dedication to serving the American people. Full Article
late What Does a Changing Climate Mean for the Fish on Your Plate? By Published On :: Mon, 01 Feb 2021 05:00:00 GMT Research by Gulf Research Program Early-Career Research Fellow Amina Schartup Explores How Mercury Levels in Fish May Rise with Climate Change Full Article
late Latest IPCC Report Says Impacts of Climate Change Are Irreversible and Widespread - Urges Efforts to Cut Emissions and Adapt By Published On :: Mon, 28 Feb 2022 05:00:00 GMT A new report from the Intergovernmental Panel on Climate Change (IPCC) warns the increasingly numerous and widespread impacts of climate change may soon overcome our ability to adapt, unless action is taken to reduce emissions. Full Article
late Gulf Research Program Awards $3.4 Million To Reduce the Burden of Disaster-Related Mental Health Consequences By Published On :: Fri, 14 Oct 2022 04:00:00 GMT The Gulf Research Program (GRP) of the National Academies of Sciences, Engineering, and Medicine today announced awards totaling $3.4 million to support four projects that reduce the burden of disaster-related mental health consequences with a focus on acute disasters. Full Article
late National Academies’ Roundtable on Macroeconomics and Climate-Related Risks and Opportunities to Hold First Public Meeting on Jan. 23 By Published On :: Fri, 20 Jan 2023 05:00:00 GMT A new roundtable will hold its first public meeting on Jan. 23 to discuss challenges associated with incorporating climate change into the macroeconomic analyses used for federal policymaking. The roundtable’s activities will inform a new White House interagency working group. Full Article
late More Investment and Attention Needed to Address Pandemic-Related Harms on Children and Families in Marginalized Communities By Published On :: Thu, 16 Mar 2023 04:00:00 GMT Strengthening and expanding critical safety net programs is necessary to address the COVID-19 pandemic’s effects on children and families, says a new report that examines the substantial toll the pandemic has taken on their health and well-being, especially those in marginalized communities. Full Article
late Simulate Home Battery Management System By blogs.mathworks.com Published On :: Tue, 15 Aug 2023 09:15:23 +0000 Jiro's Pick this week is Home Battery Energy Management System by Rodney Tan.I met Dr. Rodney Tan at a virtual educator workshop we held last year, and there I learned that he is very active in the... read more >> Full Article Picks
late Internet Archive's digital book lending violates copyrights, US judge rules By cio.economictimes.indiatimes.com Published On :: Mon, 27 Mar 2023 07:48:00 +0530 The ruling by U.S. District Judge John Koeltl in Manhattan on Friday came in a closely watched lawsuit that tested the ability of Internet Archive to lend out the works of writers and publishers protected by U.S. copyright laws. Full Article
late Scientists expect to calculate amount of fuel inside Earth by 2025 By esciencenews.com Published On :: Sun, 11 Sep 2016 10:07:17 +0000 Earth requires fuel to drive plate tectonics, volcanoes and its magnetic field. Like a hybrid car, Earth taps two sources of energy to run its engine: primordial energy from assembling the planet and nuclear energy from the heat produced during natural radioactive decay. Scientists have developed numerous models to predict how much fuel remains inside Earth to drive its engines -- and estimates vary widely -- but the true amount remains unknown. read more Full Article Physics & Chemistry
late Centre to develop tech for highspeed, ultra-low latency 5G services By cio.economictimes.indiatimes.com Published On :: Sat, 09 Nov 2024 12:11:01 +0530 To further ensure high-speed and ultra-low latency services required in 5G, the Department of Telecommunications (DoT) on Saturday said it has signed an agreement with Linearized Amplifier Technology Services and Vedang Radio Tech. Full Article
late Echo templates aid mental mapping in bats By esciencenews.com Published On :: Tue, 02 Aug 2016 18:04:57 +0000 A study published in eLife provides new insights on how bats recognise their surroundings to help them build mental maps. read more Full Article Mathematics & Economics
late 158: Is AI Still Doom? (Humans Need Not Apply – 10 Years Later) By relay.fm Published On :: Fri, 23 Aug 2024 18:15:00 GMT Full Article