Journal of Applied Crystallography最新文献

{"title":"Electronic angle focusing for neutron time-of-flight powder diffractometers.","authors":"Robert B Von Dreele","doi":"10.1107/S1600576724008756","DOIUrl":"10.1107/S1600576724008756","url":null,"abstract":"<p><p>A neutron time-of-flight (TOF) powder diffractometer with a continuous wide-angle array of detectors can be electronically focused to make a single pseudo-constant wavelength diffraction pattern, thus facilitating angle-dependent intensity corrections. The resulting powder diffraction peak profiles are affected by the neutron source emission profile and resemble the function currently used for TOF diffraction.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460386/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Link between b.c.c.-f.c.c. orientation relationship and austenite morphology in CF8M stainless steel.","authors":"Maxime Mollens, Adrien Guery, Dominique Loisnard, François Hild, Stéphane Roux","doi":"10.1107/S1600576724008392","DOIUrl":"10.1107/S1600576724008392","url":null,"abstract":"<p><p>Slow-cooled CF8M duplex stainless steel is used for critical parts of the primary coolant pipes of nuclear reactors. This steel can endure severe service conditions, but it tends to become more brittle upon very long-term aging (tens of years). Therefore, it is essential to understand its specific microstructure and temporal evolution. As revealed by electron backscatter diffraction (EBSD) analyses, the microstructure consists of millimetre-scale ferritic grains within which austenite lath packets have grown with preferred crystallographic orientations concerning the parent ferritic phase far from the ferrite grain boundaries. In these lath packets where the austenite phase is nucleated, the lath morphology and crystal orientation accommodate the two ferrite orientations. Globally, the Pitsch orientation relationship appears to display the best agreement with the experimental data compared with other classical relationships. The austenite lath packets are parallel plate-shaped laths, characterized by their normal <b>n</b>. A novel methodology is introduced to elucidate the expected relationship between <b>n</b> and the crystallographic orientation given the coarse interfaces, even though <b>n</b> is only partly known from the observation surface, in contrast to the 3D crystal orientations measured by EBSD. The distribution of retrieved normals <b>n</b> is shown to be concentrated over a set of discrete orientations. Assuming that the ferrite and austenite obey the Pitsch orientation relationship, the determined lath normals are close to an invariant direction of the parent phase given by the same orientation relationship.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460382/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of sub-micrometre-sized voids in fixed human brain tissue using scanning X-ray microdiffraction.","authors":"Prakash Nepal, Abdullah A Bashit, Lee Makowski","doi":"10.1107/S1600576724008987","DOIUrl":"10.1107/S1600576724008987","url":null,"abstract":"<p><p>Using a 5 µm-diameter X-ray beam, we collected scanning X-ray microdiffraction in both the small-angle (SAXS) and the wide-angle (WAXS) regimes from thin sections of fixed human brain tissue from Alzheimer's subjects. The intensity of scattering in the SAXS regime of these patterns exhibits essentially no correlation with the observed intensity in the WAXS regime, indicating that the structures responsible for these two portions of the diffraction patterns, which reflect different length scales, are distinct. SAXS scattering exhibits a power-law behavior in which the log of intensity decreases linearly with the log of the scattering angle. The slope of the log-log curve is roughly proportional to the intensity in the SAXS regime and, surprisingly, inversely proportional to the intensity in the WAXS regime. We interpret these observations as being due to the presence of sub-micrometre-sized voids formed during dehydration of the fixed tissue. The SAXS intensity is due largely to scattering from these voids, while the WAXS intensity derives from the secondary structures of macromolecular material surrounding the voids. The ability to detect and map the presence of voids within thin sections of fixed tissue has the potential to provide novel information on the degradation of human brain tissue in neurodegenerative diseases.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460389/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>SUBGROUPS</i>: a computer tool at the Bilbao Crystallographic Server for the study of pseudo-symmetric or distorted structures.","authors":"Emre S Tasci, Luis Elcoro, J Manuel Perez-Mato, Gemma de la Flor, Mois I Aroyo","doi":"10.1107/S1600576724008070","DOIUrl":"10.1107/S1600576724008070","url":null,"abstract":"<p><p><i>SUBGROUPS</i> is a free online program at the Bilbao Crystallographic Server (https://www.cryst.ehu.es/). It permits the exploration of all possible symmetries resulting from the distortion of a higher-symmetry parent structure, provided that the relation between the lattices of the distorted and parent structures is known. The program calculates all the subgroups of the parent space group which comply with this relation. The required minimal input is the space-group information of the parent structure and the relation of the unit cell of the distorted or pseudo-symmetric structure with that of the parent structure. Alternatively, the wavevector(s) observed in the diffraction data characterizing the distortion can be introduced. Additional conditions can be added, including filters related to space-group representations. The program provides very detailed information on all the subgroups, including group-subgroup hierarchy graphs. If a Crystallographic Information Framework (CIF) file of the parent high-symmetry structure is uploaded, the program generates CIF files of the parent structure described under each of the chosen lower symmetries. These CIF files may then be used as starting points for the refinement of the distorted structure under these possible symmetries. They can also be used for density functional theory calculations or for any other type of analysis. The power and efficiency of the program are illustrated with a few examples.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460388/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>In situ</i> counter-diffusion crystallization and long-term crystal preservation in microfluidic fixed targets for serial crystallography.","authors":"Zhongrui Liu, Kevin Gu, Megan Shelby, Debdyuti Roy, Srinivasan Muniyappan, Marius Schmidt, Sankar Raju Narayanasamy, Matthew Coleman, Matthias Frank, Tonya L Kuhl","doi":"10.1107/S1600576724007544","DOIUrl":"10.1107/S1600576724007544","url":null,"abstract":"<p><p>Compared with batch and vapor diffusion methods, counter diffusion can generate larger and higher-quality protein crystals yielding improved diffraction data and higher-resolution structures. Typically, counter-diffusion experiments are conducted in elongated chambers, such as glass capillaries, and the crystals are either directly measured in the capillary or extracted and mounted at the X-ray beamline. Despite the advantages of counter-diffusion protein crystallization, there are few fixed-target devices that utilize counter diffusion for crystallization. In this article, different designs of user-friendly counter-diffusion chambers are presented which can be used to grow large protein crystals in a 2D polymer microfluidic fixed-target chip. Methods for rapid chip fabrication using commercially available thin-film materials such as Mylar, propyl-ene and Kapton are also detailed. Rules of thumb are provided to tune the nucleation and crystal growth to meet users' needs while minimizing sample consumption. These designs provide a reliable approach to forming large crystals and maintaining their hydration for weeks and even months. This allows ample time to grow, select and preserve the best crystal batches before X-ray beam time. Importantly, the fixed-target microfluidic chip has a low background scatter and can be directly used at beamlines without any crystal handling, enabling crystal quality to be preserved. The approach is demonstrated with serial diffraction of photoactive yellow protein, yielding 1.32 Å resolution at room temperature. Fabrication of this standard microfluidic chip with commercially available thin films greatly simplifies fabrication and provides enhanced stability under vacuum. These advances will further broaden microfluidic fixed-target utilization by crystallographers.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460377/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurable structure factors of dense dispersions containing polydisperse optically inhomogeneous particles.","authors":"Joel Diaz Maier, Katharina Gaus, Joachim Wagner","doi":"10.1107/S1600576724007957","DOIUrl":"10.1107/S1600576724007957","url":null,"abstract":"<p><p>Here, it is investigated how optical properties of single scatterers in interacting multi-particle systems influence measurable structure factors. Both particles with linear gradients of their scattering length density and core-shell structures evoke characteristic deviations between the weighted sum 〈<i>S</i>(<i>Q</i>)〉 of partial structure factors in a multi-component system and experimentally accessible measurable structure factors <i>S</i> _M(<i>Q</i>). While 〈<i>S</i>(<i>Q</i>)〉 contains only the structural information of self-organizing systems, <i>S</i> _M(<i>Q</i>) is additionally influenced by the optical properties of their constituents, resulting in features such as changing amplitudes, additional peaks in the low-wavevector region or splitting of higher-order maxima, which are not related to structural reasons. It is shown that these effects can be systematically categorized according to the qualitative behaviour of the form factor in the Guinier region, which enables assessing the suitability of experimentally obtained structure factors to genuinely represent the microstructure of complex systems free from any particular model assumption. Hence, a careful data analysis regarding size distribution and optical properties of single scatterers is mandatory to avoid a misinterpretation of measurable structure factors.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460387/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pinhole small-angle neutron scattering based approach for desmearing slit ultra-small-angle neutron scattering data.","authors":"Vasyl Ryukhtin, Adél Len, László Almásy, Ewa Juszyńska-Gałązka, Wojciech Zając, Oleksandr Tomchuk","doi":"10.1107/S1600576724008380","DOIUrl":"10.1107/S1600576724008380","url":null,"abstract":"<p><p>Presented here is an effective approach to desmearing slit ultra-small-angle neutron scattering (USANS) data, based on complementary small-angle neutron scattering (SANS) measurements, leading to a seamless merging of these data sets. The study focuses on the methodological aspects of desmearing USANS data, which can then be presented in the conventional manner of SANS, enabling a broader pool of data analysis methods. The key innovation lies in the use of smeared SANS data for extrapolating slit USANS, offering a self-consistent integrand function for desmearing with Lake's iterative method. The proposed approach is validated through experimental data on porous anodized aluminium oxide membranes, showcasing its applicability and benefits. The findings emphasize the importance of accurate desmearing for merging USANS and SANS data in the crossover <i>q</i> region, which is particularly crucial for complex scattering patterns.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460380/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deconstructing 3D growth rates from transmission microscopy images of facetted crystals as captured <i>in situ</i> within supersaturated aqueous solutions.","authors":"Cai Y Ma, Chen Jiang, Thomas P Ilett, Thomas A Hazlehurst, David C Hogg, Kevin J Roberts","doi":"10.1107/S1600576724008173","DOIUrl":"10.1107/S1600576724008173","url":null,"abstract":"<p><p>Here, a morphologically based approach is used for the <i>in situ</i> characterization of 3D growth rates of facetted crystals from the solution phase. Crystal images of single crystals of the β-form of l-glutamic acid are captured <i>in situ</i> during their growth at a relative supersaturation of 1.05 using transmission optical microscopy. The crystal growth rates estimated for both the {101} capping and {021} prismatic faces through image processing are consistent with those determined using reflection light mode [Jiang, Ma, Hazlehurst, Ilett, Jackson, Hogg & Roberts (2024 ▸). <i>Cryst. Growth Des.</i> <b>24</b>, 3277-3288]. The growth rate in the {010} face is, for the first time, estimated from the shadow widths of the {021} prismatic faces and found to be typically about half that of the {021} prismatic faces. Analysis of the 3D shape during growth reveals that the initial needle-like crystal morphology develops during the growth process to become more tabular, associated with the Zingg factor evolving from 2.9 to 1.7 (>1). The change in relative solution supersaturation during the growth process is estimated from calculations of the crystal volume, offering an alternative approach to determine this dynamically from visual observations.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460390/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy-dispersive Laue diffraction analysis of the influence of statherin and histatin on the crystallographic texture during human dental enamel demineralization.","authors":"Charbel Sakr, Mohammed Al-Mosawi, Tilman A Grünewald, Philip Cook, Pieter Tack, Laszlo Vincze, Jean-Sebastien Micha, Paul Anderson, Maisoon Al-Jawad, Helga C Lichtenegger","doi":"10.1107/S1600576724007180","DOIUrl":"10.1107/S1600576724007180","url":null,"abstract":"<p><p>Energy-dispersive Laue diffraction (EDLD) is a powerful method to obtain position-resolved texture information in inhomogeneous biological samples without the need for sample rotation. This study employs EDLD texture scanning to investigate the impact of two salivary peptides, statherin (STN) and histatin-1 (HTN) 21 <i>N</i>-terminal peptides (STN21 and HTN21), on the crystallographic structure of dental enamel. These proteins are known to play crucial roles in dental caries progression. Three healthy incisors were randomly assigned to three groups: artificially demineralized, demineralized after HTN21 peptide pre-treatment and demineralized after STN21 peptide pre-treatment. To understand the micro-scale structure of the enamel, each specimen was scanned from the enamel surface to a depth of 250 µm using microbeam EDLD. Via the use of a white beam and a pixelated detector, where each pixel functions as a spectrometer, pole figures were obtained in a single exposure at each measurement point. The results revealed distinct orientations of hydroxyapatite crystallites and notable texture variation in the peptide-treated demineralized samples compared with the demineralized control. Specifically, the peptide-treated demineralized samples exhibited up to three orientation populations, in contrast to the demineralized control which displayed only a single orientation population. The texture index of the demineralized control (2.00 ± 0.21) was found to be lower than that of either the STN21 (2.32 ± 0.20) or the HTN21 (2.90 ± 0.46) treated samples. Hence, texture scanning with EDLD gives new insights into dental enamel crystallite orientation and links the present understanding of enamel demineralization to the underlying crystalline texture. For the first time, the feasibility of EDLD texture measurements for quantitative texture evaluation in demineralized dental enamel samples is demonstrated.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460385/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The AUREX cell: a versatile <i>operando</i> electrochemical cell for studying catalytic materials using X-ray diffraction, total scattering and X-ray absorption spectroscopy under working conditions.","authors":"Sara Frank, Marcel Ceccato, Henrik S Jeppesen, Melissa J Marks, Mads L N Nielsen, Ronghui Lu, Jens Jakob Gammelgaard, Jonathan Quinson, Ruchi Sharma, Julie S Jensen, Sara Hjelme, Cecilie Friberg Klysner, Simon J L Billinge, Justus Just, Frederik H Gjørup, Jacopo Catalano, Nina Lock","doi":"10.1107/S1600576724007817","DOIUrl":"10.1107/S1600576724007817","url":null,"abstract":"<p><p>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) <i>operando</i> 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 <i>operando</i> total scattering, diffraction and absorption spectroscopy as well as simultaneous combinations thereof on a commercial silver electrocatalyst for proof of concept. This combination of <i>operando</i> 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 <i>M</i> 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 <i>operando</i> 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.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11460379/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142390736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}