| 1. |
- Li, Shuting, et al.
(författare)
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Direct structure determination of vemurafenib polymorphism from compact spherulites using 3D electron diffraction
- 2023
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Ingår i: Communications Chemistry. - : Springer Science and Business Media LLC. - 2399-3669. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The spherulitic morphology is considered to be the most common morphology of crystalline materials and is particularly apparent in melt-crystallized products. Yet, historically, the polycrystalline nature of spherulites has hindered successful crystal structure determination. Here, we report the direct structure determination of a clinical drug, vemurafenib (VMN), in compact spherulite form using 3D electron diffraction (3D ED). VMN has four known polymorphs. We first solved the crystal structures of α-, β-, and γ-VMN from compact spherulites using 3D ED, and the resulting structures were highly consistent with those obtained by single-crystal X-ray diffraction. We then determined the crystal structure of δ-VMN—the least stable polymorph which cannot be cultivated as a single crystal—directly from the compact spherulite sample. We unexpectedly discovered a new polymorph during our studies, denoted as ε-VMN. Single crystals of ε-VMN are extremely thin and not suitable for study by X-ray diffraction. Again, we determined the structure of ε-VMN in a compact spherulite form. This successful structure elucidation of all five VMN polymorphs demonstrates the possibility of directly determining structures from melt-grown compact spherulite samples. Thereby, this discovery will improve the efficiency and broaden the scope of polymorphism research, especially within the field of melt crystallization.
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| 2. |
- Lightowler, Molly, et al.
(författare)
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Phase identification and discovery of an elusive polymorph of drug-polymer inclusion complex using automated 3D electron diffraction
- 2024
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Ingår i: Angewandte Chemie International Edition. - 1433-7851 .- 1521-3773. ; 63:16
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Tidskriftsartikel (refereegranskat)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.
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| 3. |
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| 4. |
- Lightowler, Molly, et al.
(författare)
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Indomethacin Polymorph δ Revealed To Be Two Plastically Bendable Crystal Forms by 3D Electron Diffraction : Correcting a 47-Year-Old Misunderstanding
- 2022
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 61:7
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Tidskriftsartikel (refereegranskat)abstract
- Indomethacin is a clinically classical non-steroidal anti-inflammatory drug that has been marketed since 1965. The third polymorph, Form δ, was discovered by both melt and solution crystallization in 1974. δ-indomethacin cannot be cultivated as large single crystals suitable for X-ray crystallography and, therefore, its crystal structure has not yet been determined. Here, we report the structure elucidation of δ-indomethacin by 3D electron diffraction and reveal the truth that melt-crystallized and solution-crystallized δ-indomethacin are in fact two polymorphs with different crystal structures. We propose to keep the solution-crystallized polymorph as Form δ and name the melt-crystallized polymorph as Form θ. Intriguingly, both structures display plastic flexibility based on a slippage mechanism, making indomethacin the first drug to have two plastic polymorphs. This discovery and correction of a 47-year-old misunderstanding signify that 3D electron diffraction has become a powerful tool for polymorphic structural studies.
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| 5. |
- Lin, Hongyi, et al.
(författare)
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How generative adversarial networks promote the development of intelligent transportation systems: A survey
- 2023
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Ingår i: IEEE/CAA Journal of Automatica Sinica. - 2329-9274 .- 2329-9266. ; 10:9, s. 1781-1796
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Tidskriftsartikel (refereegranskat)abstract
- In current years, the improvement of deep learning has brought about tremendous changes: As a type of unsupervised deep learning algorithm, generative adversarial networks (GANs) have been widely employed in various fields including transportation. This paper reviews the development of GANs and their applications in the transportation domain. Specifically, many adopted GAN variants for autonomous driving are classified and demonstrated according to data generation, video trajectory prediction, and security of detection. To introduce GANs to traffic research, this review summarizes the related techniques for spatio-temporal, sparse data completion, and time-series data evaluation. GAN-based traffic anomaly inspections such as infrastructure detection and status monitoring are also assessed. Moreover, to promote further development of GANs in intelligent transportation systems (ITSs), challenges and noteworthy research directions on this topic are provided. In general, this survey summarizes 130 GAN-related references and provides comprehensive knowledge for scholars who desire to adopt GANs in their scientific works, especially transportation-related tasks.
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| 6. |
- Lin, Hongyi, et al.
(författare)
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Insights into Travel Pattern Analysis and Demand Prediction: A Data-Driven Approach in Bike-Sharing Systems
- 2024
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Ingår i: Journal of Transportation Engineering Part A: Systems. - 2473-2893 .- 2473-2907. ; 150:2
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Tidskriftsartikel (refereegranskat)abstract
- With the advent of the Internet of Things, bike-sharing systems have seen widespread adoption globally, whereas they often grapple with an uneven spatiotemporal distribution of vehicles. This issue is particularly acute in the wake of electronic fences, with some areas often faced with the predicament of inadequate supply. To tackle this challenge, accurate prediction of borrowing and returning demands at different parking spots and varying times is necessary. In this study, we used a comprehensive data set from Yancheng, Jiangsu, China, covering shared bicycle usage across 394 parking spots. These data enabled us to delve deep into urban travel patterns and discern the various factors influencing these behaviors. To enhance the prediction accuracy, we propose the time-series weighted regression (TSWR) model, a long-term multistep forecasting method, which adeptly addresses issues associated with sparse statistical data and long-term prediction inaccuracies, outperforming other machine learning models in our experiments. Further recognizing the considerable impact of geographical location and weather conditions on shared bicycle demand, we incorporated the rule-based adjustment optimization (RAO) method into our approach, which refines nonlinear components by accounting for various factors. The implementation of RAO resulted in a 10.34% increase in accuracy compared to TSWR alone and an improvement of over 35% in comparison to other approaches. Overall, this study illuminates the underlying influences on urban travel patterns and offers valuable suggestions for bike dispatching to those enterprises, contributing significantly to the research in this field.
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| 7. |
- McMillan, Hilary, et al.
(författare)
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Panta Rhei 2013-2015 : global perspectives on hydrology, society and change
- 2016
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Ingår i: Hydrological Sciences Journal. - : Taylor & Francis Group. - 0262-6667 .- 2150-3435. ; 61:7, s. 1174-1191
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Tidskriftsartikel (refereegranskat)abstract
- In 2013, the International Association of Hydrological Sciences (IAHS) launched the hydrological decade 2013-2022 with the theme "Panta Rhei: Change in Hydrology and Society". The decade recognizes the urgency of hydrological research to understand and predict the interactions of society and water, to support sustainable water resource use under changing climatic and environmental conditions. This paper reports on the first Panta Rhei biennium 2013-2015, providing a comprehensive resource that describes the scope and direction of Panta Rhei. We bring together the knowledge of all the Panta Rhei working groups, to summarize the most pressing research questions and how the hydrological community is progressing towards those goals. We draw out interconnections between different strands of research, and reflect on the need to take a global view on hydrology in the current era of human impacts and environmental change. Finally, we look back to the six driving science questions identified at the outset of Panta Rhei, to quantify progress towards those aims.
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| 8. |
- Sun, Pengliang, et al.
(författare)
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Round-the-clock bifunctional honeycomb-like nitrogen-doped carbon-decorated Co2P/Mo2C-heterojunction electrocatalyst for direct water splitting with 18.1% STH efficiency
- 2022
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Ingår i: Applied Catalysis B. - : Elsevier. - 0926-3373 .- 1873-3883. ; 310
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen production via solar and electrochemical water splitting is a promising approach for storing solar energy and achieving a carbon-neutral economy. However, hydrogen production by photoelectric coupling remains a challenge. Here, by the cooperative coupling of heteroatoms and a heterojunction interface engineering strategy in a limited space, a honeycomb porous Co2P/Mo2C@NC catalyst was obtained for the first time. In contrast most traditional chemical syntheses, this method maintains excellent electrical interconnections among the nanoparticles and results in large surface areas and many catalytically active sites. Theoretical calculations reveal that the construction of a heterostructure can effectively lower the hydrogen evolution reaction and oxygen evolution reaction barriers as well as improve the electrical conductivity, consequently enhancing the electrochemical performance. Significantly, the overall water-splitting hydrolytic tank assembled using AsGa solar cells enabled the system to achieve a stable solar hydrogen conversion efficiency of 18.1%, which provides a new approach for facilitating large-scale hydrogen production via portable water hydrolysis driven by solar cells.
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| 9. |
- Tan, Fang, et al.
(författare)
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Improving the hydrogen evolution reaction activity of molybdenum-based heterojunction nanocluster capsules via electronic modulation by erbium–nitrogen–phosphorus ternary doping
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 454:Part 1
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Tidskriftsartikel (refereegranskat)abstract
- The realization of a hydrogen-based economy with robust hydrogen evolution reaction catalysts remains a challenge. In this study, we prepared MoO2/Mo2N3 heterostructure nanoclusters co-doped with nitrogen, phosphorus, and erbium for the first time. The introduction of the nitrogen and phosphorus atoms into the transition metal increases the d-electron density and contracts the d-band, which leads to a rearranged electronic structure of the MoO2/Mo2N3 heterojunction. The coupling of the rare earth erbium dopant with the valence band of the heterojunction leads to the redistribution of the electron density in the catalyst and promotes covalent interaction with the adsorbed intermediates, thereby optimizing the Gibbs free energy of intermediate adsorption and improving the catalytic activity for the hydrogen evolution reaction. Not only is an efficient and economical catalyst for electrolytic aquatic hydrogen production provided in this work, but a new synthesis scheme is also proposed for the rational synthesis of homologous core–shell polymetallic nanostructures with broad application prospects.
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| 10. |
- Xiong, Ailun, et al.
(författare)
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Determinants of Social Networks in Rural China : Does Transportation Have a Role to Play?
- 2019
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Ingår i: Social Science Quarterly. - : Wiley. - 0038-4941 .- 1540-6237. ; 100:5, s. 1709-1725
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: In recent years, the origins and sources of social networks and social capital have been extensively studied. Previous studies have primarily focused on social demographic factors. To enrich our understanding of the determinants of social networks, this article explores the role of mobility in rural China. Methods: Drawing upon a data set from the Chinese General Social Survey, this article first uses clustered effect logit models and then adopts a propensity score matching (PSM) model for a robustness check. Results: The results demonstrate that citizens who have access to more advanced transportation modes and spend less time on traveling are more likely to establish weak ties, especially with nonagricultural citizens in prestigious job positions. The results also indicate that strong family ties are not the consequence of mobility. By disaggregating the full sample, this article further reveals that the young, rich, and female citizens reap more benefit from mobility. Conclusions: Given the great importance of automobiles for strengthening social networks, this article suggests that car sharing/pooling/lifting programs might be a viable solution to social network deficits in rural areas.
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