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1,918 results on '"Zou , Xiaodong"'

3. Tautomerism unveils a self-inhibition mechanism of crystallization

Author

Tang, Weiwei, Yang, Taimin, Morales-Rivera, Cristian A, Geng, Xi, Srirambhatla, Vijay K, Kang, Xiang, Chauhan, Vraj P, Hong, Sungil, Tu, Qing, Florence, Alastair J, Mo, Huaping, Calderon, Hector A, Kisielowski, Christian, Hernandez, Francisco C Robles, Zou, Xiaodong, Mpourmpakis, Giannis, and Rimer, Jeffrey D

Subjects
Biochemistry and Cell Biology, Chemical Sciences, Biological Sciences
Abstract

Modifiers are commonly used in natural, biological, and synthetic crystallization to tailor the growth of diverse materials. Here, we identify tautomers as a new class of modifiers where the dynamic interconversion between solute and its corresponding tautomer(s) produces native crystal growth inhibitors. The macroscopic and microscopic effects imposed by inhibitor-crystal interactions reveal dual mechanisms of inhibition where tautomer occlusion within crystals that leads to natural bending, tunes elastic modulus, and selectively alters the rate of crystal dissolution. Our study focuses on ammonium urate crystallization and shows that the keto-enol form of urate, which exists as a minor tautomer, is a potent inhibitor that nearly suppresses crystal growth at select solution alkalinity and supersaturation. The generalizability of this phenomenon is demonstrated for two additional tautomers with relevance to biological systems and pharmaceuticals. These findings offer potential routes in crystal engineering to strategically control the mechanical or physicochemical properties of tautomeric materials.

Published
2023

9. Improving data quality for 3D electron diffraction (3D ED) by Gatan Image Filter and a new crystal tracking method

Author

Yang, Taimin, Xu, Hongyi, and Zou, Xiaodong

Subjects
Physics - Chemical Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

3D ED is an effective technique to determine the structures of submicron- or nano-sized crystals. In this paper, we implemented energy-filtered 3D ED using a Gatan Energy Filter (GIF) in both selected area electron diffraction mode and micro/nanoprobe mode. We explained the setup in detail, which improves the accessibility of energy-filtered 3D ED experiments as more electron microscopes are equipped with a GIF than an in-column filter. We also proposed a crystal tracking method in STEM mode using live HAADF image stream. This method enables us to collect energy-filtered 3D ED datasets in STEM mode with a larger tilt range without foregoing any frames. In order to compare the differences between energy-filtered 3D ED and normal 3D ED data, three crystalline samples have been studied in detail. We observed that the final R1 will improve 20% to 30% for energy-filtered datasets compared with unfiltered datasets and the structure became more reasonable. We also discussed the possible reasons that lead to the improvement.

Published
2021
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11. Advanced materials provide solutions towards a sustainable world

Author

Hultman, Lars, Mazur, Sara, Ankarcrona, Caroline, Palmqvist, Anders, Abrahamsson, Maria, Antti, Marta-Lena, Baltzar, Malin, Bergström, Lennart, de Laval, Pontus, Edman, Ludvig, Erhart, Paul, Kloo, Lars, Lundberg, Mats W., Mikkelsen, Anders, Moons, Ellen, Persson, Cecilia, Rensmo, Håkan, Rosén, Johanna, Rudén, Christina, Selleby, Malin, Sundgren, Jan-Eric, Dick Thelander, Kimberly, Tybrandt, Klas, Weihed, Pär, Zou, Xiaodong, Åstrand, Maria, Björkman, Charlotte Platzer, Schneider, Jochen M., Eriksson, Olle, and Berggren, Magnus

Published
2024
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16. InsteaDMatic: Towards cross-platform automated continuous rotation electron diffraction

Author

Roslova, Maria, Smeets, Stef, Wang, Bin, Thersleff, Thomas, Xu, Hongyi, and Zou, Xiaodong

Subjects
Condensed Matter - Materials Science
Abstract

A DigitalMicrograph script InsteaDMatic has been developed to facilitate rapid automated continuous rotation electron diffraction (cRED) data acquisition. The script coordinates microscope functions, such as stage rotation, camera functions relevant for data collection, and stores the experiment metadata. The script is compatible with any microscope that can be controlled by DigitalMicrograph and has been tested on both JEOL and Thermo Fisher Scientific microscopes. A proof-of-concept has been performed through employing InsteaDMatic for data collection and structure determination of a ZSM-5 zeolite. The influence of illumination settings and electron dose rate on the quality of diffraction data, unit cell determination and structure solution has been investigated in order to optimize the data acquisition procedure.

Published
2019

34. Phase identification and discovery of an elusive polymorph of drug-polymer inclusion complex using automated 3D electron diffraction

Author

Lightowler, Molly, Li, Shuting, Ou, Xiao, Cho, Jung, Liu, Binbin, Li, Ao, Hofer, Gerhard, Xu, Jiaoyan, Yang, Taimin, Zou, Xiaodong, Lu, Ming, Xu, Hongyi, Lightowler, Molly, Li, Shuting, Ou, Xiao, Cho, Jung, Liu, Binbin, Li, Ao, Hofer, Gerhard, Xu, Jiaoyan, Yang, Taimin, Zou, Xiaodong, Lu, Ming, and Xu, Hongyi

Abstract

3D electron diffraction (3D ED) has shown great potential in crystal structure determination in materials, small organic molecules, and macromolecules. In this work, an automated, low-dose and low-bias 3D ED protocol has been implemented to identify six phases from a multiple-phase melt-crystallisation product of an active pharmaceutical ingredient, griseofulvin (GSF). Batch data collection under low-dose conditions using a widely available commercial software was combined with automated data analysis to collect and process over 230 datasets in three days. Accurate unit cell parameters obtained from 3D ED data allowed direct phase identification of GSF Forms III, I and the known GSF inclusion complex (IC) with polyethylene glycol (PEG) (GSF-PEG IC-I), as well as three minor phases, namely GSF Forms II, V and an elusive new phase, GSF-PEG IC-II. Their structures were then directly determined by 3D ED. Furthermore, we reveal how the stabilities of the two GSF-PEG IC polymorphs are closely related to their crystal structures. These results demonstrate the power of automated 3D ED for accurate phase identification and direct structure determination of complex, beam-sensitive crystallisation products, which is significant for drug development where solid form screening is crucial for the overall efficacy of the drug product.

Published
2024
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35. STEM SerialED : achieving high-resolution data for ab initio structure determination of beam-sensitive nanocrystalline materials

Author

Hogan-Lamarre, Pascal, Luo, Yi, Bücker, Robert, Miller, R. J. Dwayne, Zou, Xiaodong, Hogan-Lamarre, Pascal, Luo, Yi, Bücker, Robert, Miller, R. J. Dwayne, and Zou, Xiaodong

Abstract

Serial electron diffraction (SerialED), which applies a snapshot data acquisition strategy for each crystal, was introduced to tackle the problem of radiation damage in the structure determination of beam-sensitive materials by three-dimensional electron diffraction (3DED). The snapshot data acquisition in SerialED can be realized using both transmission and scanning transmission electron microscopes (TEM/STEM). However, the current SerialED workflow based on STEM setups requires special external devices and software, which limits broader adoption. Here, we present a simplified experimental implementation of STEM-based SerialED on Thermo Fisher Scientific STEMs using common proprietary software interfaced through Python scripts to automate data collection. Specifically, we utilize TEM Imaging and Analysis (TIA) scripting and TEM scripting to access the STEM functionalities of the microscope, and DigitalMicrograph scripting to control the camera for snapshot data acquisition. Data analysis adapts the existing workflow using the software CrystFEL, which was developed for serial X-ray crystallography. Our workflow for STEM SerialED can be used on any Gatan or Thermo Fisher Scientific camera. We apply this workflow to collect high-resolution STEM SerialED data from two aluminosilicate zeolites, zeolite Y and ZSM-25. We demonstrate, for the first time, ab initio structure determination through direct methods using STEM SerialED data. Zeolite Yis relatively stable under the electron beam, and STEM SerialED data extend to 0.60 angstrom. We show that the structural model obtained using STEM SerialED data merged from 358 crystals is nearly identical to that using continuous rotation electron diffraction data from one crystal. This demonstrates that accurate structures can be obtained from STEM SerialED. Zeolite ZSM-25 is very beam-sensitive and has a complex structure. We show that STEM SerialED greatly improves the data resolution of ZSM-25, compared with serial rotation el

Published
2024
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37. Understanding Element Transfer Behaviors of CaF2–TiO2 Flux-Cored Wires Under High Heat Input Electro-Gas Welding.

Author

Xie, Xu, Zou, Xiaodong, Zhong, Ming, Basu, Somnath, and Wang, Cong

Subjects
WELDING, SHIPBUILDING, STEEL, WIRE
Abstract

CaF2–TiO2 fluxes are designed and applied into flux-cored wires suitable for high heat input electro-gas welding of EH36 shipbuilding steel. It has been demonstrated that decomposing CO2 and TiO2 caused by arc synergistically contributes O and Ti gains in the weld pool, while more SiO2 and MnO formation at the slag-metal interface induces the loss of Si (from − 0.012 to − 0.046 wt pct) and Mn (from − 0.138 to − 0.404 wt pct) with increasing TiO2 addition. [ABSTRACT FROM AUTHOR]

Published
2024
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44. Finned zeolite catalysts

Author

Dai, Heng, Shen, Yufeng, Yang, Taimin, Lee, Choongsze, Fu, Donglong, Agarwal, Ankur, Le, Thuy Thanh, Tsapatsis, Michael, Palmer, Jeremy C., Weckhuysen, Bert M., Dauenhauer, Paul J., Zou, Xiaodong, and Rimer, Jeffrey D.

Published
2020
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