| 1. |
- Geng, Huifang, et al.
(författare)
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Controlled synthesis of highly stable lead-free bismuth halide perovskite nanocrystals : tructures and photophysics
- 2023
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Ingår i: SCIENCE CHINA Materials. - : Springer Science and Business Media LLC. - 2095-8226 .- 2199-4501. ; 66:5, s. 2079-2089
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Tidskriftsartikel (refereegranskat)abstract
- Recently, cesium bismuth halide perovskites have emerged as potential substitutes to their counterparts, cesium lead halide perovskites, owing to their low toxicity. However, the photophysics of cesium-bismuth halides nanocrystals (NCs) have not yet been fully rationalized because their structures remain highly debated. The ultraviolet-visible (UV-vis) absorption along with other photophysical properties such as the nature and lifetime of the excited states vary considerably across the previous reports. Here, we successfully synthesize pure Cs3BiBr6 and Cs3Bi2Br9 NCs via a modified hot-injection method, where the structure can be easily controlled by tuning the reaction temperature. The UV-vis absorption spectrum of the pure Cs3Bi2Br9 NCs features two characteristic peaks originating from the absorption of the first exciton and second exciton, respectively, which ultimately clarifies the debate in the previous reports. Using femtosecond transient absorption spectroscopy, we systematically investigate the excited state dynamics of the Cs3Bi2Br9 NCs and reveal that the photoexcited carriers undergo a self-trapping process within 3 ps after excitation. More intriguingly, the Cs3Bi2Br9 NCs prepared by this method show much better photostability than those prepared by the ligand-assisted reprecipitation process. Photodetectors based on these Cs3Bi2Br9 NCs show a sensitive light response, demonstrating the definite potential for breakthrough optoelectronic applications. [Figure not available: see fulltext.].
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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
- Liu, Siyu, et al.
(författare)
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Probing the Multiexcitonic Dynamics in CsPbI3 Nanocrystals across the Temperature-Induced Reversible Phase Transitions
- 2023
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Ingår i: Advanced Energy Materials. - 1614-6832. ; 13:30
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Tidskriftsartikel (refereegranskat)abstract
- CsPbI3 nanocrystals (CPI NCs) have become a trending research topic due to their impressive potential in functional optoelectronic devices and optical gain applications. Their optical responses are governed by carrier dynamics, which is greatly influenced by temperature and corresponding phase structure due to the effects of inherently electron-phonon coupling. Notably, CPI NCs have been identified to adopt an unexpectedly stable cubic phase from room temperature to liquid helium temperature. Here, using in situ cryogenic electron diffraction measurements, it is unambiguously demonstrated that CPI NCs undergo consecutive cubic-tetragonal-orthorhombic phase transitions from 298 to 100 K. The corresponding temperature-dependent multiexcitonic dynamics are investigated in each phase by combining time-resolved photoluminescence and transient absorption spectroscopy. In addition to the temperature dependency, the lifetime of both excitons and biexcitons evidently depends on the phase structures of the CPI NCs, highlighting the crucial effect of crystal structure on the carrier dynamics. Moreover, the biexciton binding energy increases with higher crystal symmetry due to the decrease of the dielectric constant. The findings shed light on the structural phase transition and its relationship to the carrier dynamics in all-inorganic perovskite NCs, which provides critical insight into the structure-performance relationship in CPI NCs for promising applications in optoelectronic devices.
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| 4. |
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| 5. |
- Kong, Depeng, et al.
(författare)
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Bioinspired Co-Design of Tactile Sensor and Deep Learning Algorithm for Human-Robot Interaction
- 2022
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Ingår i: ADVANCED INTELLIGENT SYSTEMS. - : Wiley. - 2640-4567. ; 4:6
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Tidskriftsartikel (refereegranskat)abstract
- Robots equipped with bionic skins for enhancing the robot perception capability are increasingly deployed in wide applications ranging from healthcare to industry. Artificial intelligence algorithms that can provide bionic skins with efficient signal processing functions further accelerate the development of this trend. Inspired by the somatosensory processing hierarchy of humans, the bioinspired co-design of a tactile sensor and a deep learning-based algorithm is proposed herein, simplifying the sensor structure while providing computation-enhanced tactile sensing performance. The soft piezoresistive sensor, based on the carbon black-coated polyurethane sponge, offers a continuous sensing area. By utilizing a customized deep neural network (DNN), it can detect external tactile stimulus spatially continuously. Besides, a novel data augmentation method is developed based on the sensor's hexagonal structure that has a sixfold rotation symmetry. It can significantly enhance the generalization ability of the DNN model by enriching the collected training data with generated pseudo-data. The functionality of the sensor and the robustness of the proposed data augmentation strategy are verified by precisely recognizing five touch modalities, illustrating a well-generalized performance, and providing a promising application prospect in human-robot interaction.
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| 6. |
- Tang, Weiwei, et al.
(författare)
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Tautomerism unveils a self-inhibition mechanism of crystallization
- 2023
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)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.
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| 7. |
- Zhou, Huiying, et al.
(författare)
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An attention-based deep learning approach for inertial motion recognition and estimation in human-robot collaboration
- 2023
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Ingår i: Journal of manufacturing systems. - : Elsevier BV. - 0278-6125 .- 1878-6642. ; 67, s. 97-110
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Tidskriftsartikel (refereegranskat)abstract
- In line with a human-centric smart manufacturing vision, human-robot collaboration is striving to combine robots' high efficiency and quality with humans' rapid adaptability and high flexibility. In particular, perception, recognition and estimation of human motion determine when and what robot to collaborate with humans. This work presents an attention-based deep learning approach for inertial motion recognition and estimation in order to infer when robotic assistance will be requested by the human and to allow the robot to perform partial human tasks. First, in the stage of motion perception and recognition, quaternion-based calibration and forward kinematic analysis methods enable the reconstruction of human motion based on data streaming from an inertial motion capture device. Then, in the stage of motion estimation, residual module and Bidirectional Long ShortTerm Memory module are integrated with proposed attention mechanism for estimating arm motion trajectories further. Experimental results show the effectiveness of the proposed approach in achieving better recognition and estimation in comparison with traditional approaches and existing deep learning approaches. It is experimentally verified in a laboratory environment involving a collaborative robot employed in a small part assembly task.
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