Pub Date : 2024-08-27DOI: 10.1107/S1600576724006903
Yu-Hang Wang, Ming Li, Le Kang, Quan-Jie Jia
A numerical framework based on the integral solution of the Takagi–Taupin equations has been developed for cylindrically bent Laue crystals. On the basis of this framework, diffraction geometries that satisfy the `magic condition' have been studied from the perspective of dynamical theory. The numerical findings indicate that, in certain diffraction geometries, the focusing behaviour of cylindrically bent Laue crystals will be notably influenced by dynamical effects and the foci of different energies will not converge as predicted by the `magic condition', which is derived from geometric optics theory. These dynamical effects are further explained through a direct numerical analysis of the influence function.
{"title":"Revisiting the ‘magic condition’ on the basis of the Takagi–Taupin theory","authors":"Yu-Hang Wang, Ming Li, Le Kang, Quan-Jie Jia","doi":"10.1107/S1600576724006903","DOIUrl":"https://doi.org/10.1107/S1600576724006903","url":null,"abstract":"<p>A numerical framework based on the integral solution of the Takagi–Taupin equations has been developed for cylindrically bent Laue crystals. On the basis of this framework, diffraction geometries that satisfy the `magic condition' have been studied from the perspective of dynamical theory. The numerical findings indicate that, in certain diffraction geometries, the focusing behaviour of cylindrically bent Laue crystals will be notably influenced by dynamical effects and the foci of different energies will not converge as predicted by the `magic condition', which is derived from geometric optics theory. These dynamical effects are further explained through a direct numerical analysis of the influence function.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 5","pages":"1344-1357"},"PeriodicalIF":5.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1107/S1600576724006460
M. Gateshki, Th. Dortmann, Th. Degen, M. Sadki, N. Norberg
The effect of specimen displacement in X-ray powder diffraction experiments with laboratory diffractometers has been revisited and new expressions have been derived for several commonly used experimental configurations, including Bragg–Brentano parafocusing geometry and flat-plate transmission geometry. The results presented in this work allow the analysis of data from samples with relatively large displacements. This may open the possibility to study samples with dimensions that are difficult to accommodate with the sample-handling capabilities of standard laboratory diffractometers.
我们重新审视了实验室衍射仪在 X 射线粉末衍射实验中试样位移的影响，并针对几种常用的实验配置（包括布拉格-布伦塔诺准聚焦几何和平板透射几何）推导出了新的表达式。这项研究的结果允许对具有相对较大位移的样品数据进行分析。这为研究标准实验室衍射仪的样品处理能力难以适应的样品尺寸提供了可能。
{"title":"Effect of specimen displacement in X-ray powder diffraction measurements with laboratory diffractometers","authors":"M. Gateshki, Th. Dortmann, Th. Degen, M. Sadki, N. Norberg","doi":"10.1107/S1600576724006460","DOIUrl":"https://doi.org/10.1107/S1600576724006460","url":null,"abstract":"<p>The effect of specimen displacement in X-ray powder diffraction experiments with laboratory diffractometers has been revisited and new expressions have been derived for several commonly used experimental configurations, including Bragg–Brentano parafocusing geometry and flat-plate transmission geometry. The results presented in this work allow the analysis of data from samples with relatively large displacements. This may open the possibility to study samples with dimensions that are difficult to accommodate with the sample-handling capabilities of standard laboratory diffractometers.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 5","pages":"1336-1343"},"PeriodicalIF":5.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although many studies have addressed the significance of interactions in the dimeric structures of proteins, there is no dedicated database of these interactions. To this end, the Molecular Interactions in Protein Dimer Structure (MIPDS) database has been developed; it is an open-access repository containing 60 298 3D structures of dimeric proteins sourced from the Protein Data Bank. This helps researchers comprehend the types of interaction, which include those mediated by water, small molecules or ligands and direct interactions, in 3D structures at the molecular level. The database is accessible through a user-friendly interface, where users can conduct searches based on PDB accession number, interaction type and geometric parameters. It can be viewed in textual and graphical formats using the plug-in JSmol. MIPDS is updated weekly using programmed scripts to incorporate newly released dimeric structures and analyses of their interaction types. The database is intended for the scientific community working in structural biology, structural bioinformatics, drug discovery and development. MIPDS is freely accessible to users worldwide at http://dicsoft1.physics.iisc.ac.in/mipds.
{"title":"MIPDS: a comprehensive database on the molecular interactions in protein dimer structures","authors":"Madhumathi Sanjeevi, Santhosh Rajendran, Jeyakanthan Jeyaraman, Kanagaraj Sekar","doi":"10.1107/S1600576724007131","DOIUrl":"https://doi.org/10.1107/S1600576724007131","url":null,"abstract":"<p>Although many studies have addressed the significance of interactions in the dimeric structures of proteins, there is no dedicated database of these interactions. To this end, the Molecular Interactions in Protein Dimer Structure (MIPDS) database has been developed; it is an open-access repository containing 60 298 3D structures of dimeric proteins sourced from the Protein Data Bank. This helps researchers comprehend the types of interaction, which include those mediated by water, small molecules or ligands and direct interactions, in 3D structures at the molecular level. The database is accessible through a user-friendly interface, where users can conduct searches based on PDB accession number, interaction type and geometric parameters. It can be viewed in textual and graphical formats using the plug-in <i>JSmol</i>. MIPDS is updated weekly using programmed scripts to incorporate newly released dimeric structures and analyses of their interaction types. The database is intended for the scientific community working in structural biology, structural bioinformatics, drug discovery and development. MIPDS is freely accessible to users worldwide at http://dicsoft1.physics.iisc.ac.in/mipds.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"57 5","pages":"1667-1675"},"PeriodicalIF":5.2,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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