| 1. |
- Wu, Yanqing, et al.
(författare)
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Organo-Metal Halide Scintillator with Weak Thermal Quenching Up to 200 °C
- 2022
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Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 13:25, s. 5794-5800
-
Tidskriftsartikel (refereegranskat)abstract
- The prominent thermal quenching (TQ) effect of organic-inorganic metal halides limits their applications for lighting and imaging. Herein, we report an organo-metal halide scintillator (TTPhP)2MnCl4(TTPhP+= tetraphenylphosphonium cation), which exhibits a weak TQ effect up to 200 °C under ultraviolet-visible light (efficiency loss of 5.5%) and X-ray radiation (efficiency loss of 37%). The light yield of the (TTPhP)2MnCl4scintillator (37 »000 photons MeV-1at 200 °C) under X-ray radiation is >2 times that of the commercial scintillator LuAG:Ce (15 »000 photons MeV-1at 200 °C). The microscopic mechanism of the weak TQ effect is demonstrated to be the scintillator having the ability to compensate for the emission losses from trapped charges and the large Mn-Mn distance (10.233 Å) suppressing nonradiative recombination at high temperatures. We further demonstrate the applications of (TTPhP)2MnCl4as high-power white-light-emitting diodes operated at currents of ≤300 mA and X-ray imaging at 200 °C with a high spatial resolution.
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| 2. |
- Chen, Junsheng, et al.
(författare)
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Sensing Mechanism for Biothiols Chemosensor DCO: Roles of Excited-State Hydrogen-Bonding and Intramolecular Charge Transfer
- 2014
-
Ingår i: The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory. - : American Chemical Society (ACS). - 1520-5215. ; 118:39, s. 8986-8995
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Tidskriftsartikel (refereegranskat)abstract
- The biothiols sensing mechanism of (E)-7-(diethylamino)-3-(2-nitrovinyl)-2H-chromen-2-one (DCO) has been investigated using the density functional theory (DFT) and time-dependent DFT methods. The theoretical results indicate that the excited-state intermolecular hydrogen bonding (H-B) plays an important role for the biothiols sensing mechanism of the fluorescence sensor DCO. Multiple H-B interaction sites exist in DCO and in its Michael addition product DCOT, which then induce the formation of the H-B complexes with water molecules, DCOH2 and DCOTH4. In the first excited state, the intermolecular H-Bs between water molecule and DCO in DCOH2 are cooperatively and generally strengthened and thus induced the weak fluorescence emission of DCO, while the cooperative H-Bs between water molecule and DCOT in DCOTH4 are overall weakened and thus responsible for the enhanced fluorescence emission of DCOT. Moreover, the theoretical results suggest that the blue shift of the UV-Vis absorption spectrum of DCOT can be attributed to the relatively weak excited-state intramolecular charge transfer in DCOT compared to DCO.
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| 3. |
- Song, J., et al.
(författare)
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Essential Genetic Interactors of SIR2 Required for Spatial Sequestration and Asymmetrical Inheritance of Protein Aggregates
- 2014
-
Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Sir2 is a central regulator of yeast aging and its deficiency increases daughter cell inheritance of stress-and aging-induced misfolded proteins deposited in aggregates and inclusion bodies. Here, by quantifying traits predicted to affect aggregate inheritance in a passive manner, we found that a passive diffusion model cannot explain Sir2-dependent failures in mother-biased segregation of either the small aggregates formed by the misfolded Huntingtin, Htt103Q, disease protein or heat-induced Hsp104-associated aggregates. Instead, we found that the genetic interaction network of SIR2 comprises specific essential genes required for mother-biased segregation including those encoding components of the actin cytoskeleton, the actin-associated myosin V motor protein Myo2, and the actin organization protein calmodulin, Cmd1. Co-staining with Hsp104-GFP demonstrated that misfolded Htt103Q is sequestered into small aggregates, akin to stress foci formed upon heat stress, that fail to coalesce into inclusion bodies. Importantly, these Htt103Q foci, as well as the ATPase-defective Hsp104(Y662A)-associated structures previously shown to be stable stress foci, co-localized with Cmd1 and Myo2-enriched structures and super-resolution 3-D microscopy demonstrated that they are associated with actin cables. Moreover, we found that Hsp42 is required for formation of heat-induced Hsp104(Y662A) foci but not Htt103Q foci suggesting that the routes employed for foci formation are not identical. In addition to genes involved in actin-dependent processes, SIR2-interactors required for asymmetrical inheritance of Htt103Q and heat-induced aggregates encode essential sec genes involved in ER-to-Golgi trafficking/ER homeostasis.
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| 4. |
- Yang, B, et al.
(författare)
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Lead-Free, Air-Stable All-Inorganic Cesium Bismuth Halide Perovskite Nanocrystals
- 2017
-
Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 56:41, s. 12471-12475
-
Tidskriftsartikel (refereegranskat)abstract
- Lead-based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead-based and the other is the poor stability. Lead-free all-inorganic perovskite Cs3Bi2X9 (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560nm synthesized by a facile room temperature reaction. The ligand-free Cs3Bi2Br9 NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2%. The PLQE can be increased to 4.5% when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2-20ps). Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30days.
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| 5. |
- Yang, Bin, et al.
(författare)
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Lead-Free Silver-Bismuth Halide Double Perovskite Nanocrystals
- 2018
-
Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 57:19, s. 5359-5363
-
Tidskriftsartikel (refereegranskat)abstract
- Lead-free perovskite nanocrystals (NCs) were obtained mainly by substituting a Pb2+ cation with a divalent cation or substituting three Pb2+ cations with two trivalent cations. The substitution of two Pb2+ cations with one monovalent Ag+ and one trivalent Bi3+ cations was used to synthesize Cs2AgBiX6 (X=Cl, Br, I) double perovskite NCs. Using femtosecond transient absorption spectroscopy, the charge carrier relaxation mechanism was elucidated in the double perovskite NCs. The Cs2AgBiBr6 NCs exhibit ultrafast hot-carrier cooling (<1 ps), which competes with the carrier trapping processes (mainly originate from the surface defects). Notably, the photoluminescence can be increased by 100 times with surfactant (oleic acid) added to passivate the defects in Cs2AgBiCl6 NCs. These results suggest that the double perovskite NCs could be potential materials for optoelectronic applications by better controlling the surface defects.
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| 6. |
- Yang, B, et al.
(författare)
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Ultrasensitive and Fast All-Inorganic Perovskite-Based Photodetector via Fast Carrier Diffusion
- 2017
-
Ingår i: Advanced Materials. - : Wiley. - 0935-9648. ; 29:40, s. 1703758-1703758
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Tidskriftsartikel (refereegranskat)abstract
- Low trap-state density, high carrier mobility, and efficient charge carrier collection are key parameters for photodetectors with high sensitivity and fast response time. This study demonstrates a simple solution growth method to prepare CsPbBr3 microcrystals (MCs) with low trap-state density. Time-dependent photoluminescence study with one-photon excitation (OPE) and two-photon excitation (TPE) indicates that CsPbBr3 MCs exhibit fast carrier diffusion with carrier mobility over 100 cm2 V-1 S-1. Furthermore, CsPbBr3 MC-based photodetectors with high charge carriers' collection efficiency are fabricated. Such photodetectors show ultrahigh responsivity (R) up to 6 × 104 A W-1 with OPE and high R up to 6 A W-1 with TPE. The R for OPE is over one order of magnitude higher (the R for TPE is three orders of magnitude higher) than that of previously reported all-inorganic perovskite-based photodetectors. Moreover, the photodetectors exhibit fast response time of ≈1 ms, which corresponds to a gain ≈105 and a gain- bandwidth product of 108 Hz for OPE (a gain ≈103 and a gain-bandwidth product of 106 Hz for TPE).
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| 7. |
- Yin, Hang, et al.
(författare)
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Controlling Photoluminescence and Photocatalysis Activities in Lead-Free Cs2PtxSn1−xCl6 Perovskites via Ion Substitution
- 2021
-
Ingår i: Angewandte Chemie - International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 60:42, s. 22693-22699
-
Tidskriftsartikel (refereegranskat)abstract
- Lead-free halide perovskites have triggered interest in the field of optoelectronics and photocatalysis because of their low toxicity, and tunable optical and charge-carrier properties. From an application point of view, it is desirable to develop stable multifunctional lead-free halide perovskites. We have developed a series of Cs2PtxSn1−xCl6 perovskites (0≤x≤1) with high stability, which show switchable photoluminescence and photocatalytic functions by varying the amount of Pt4+ substitution. A Cs2PtxSn1−xCl6 solid solution with a dominant proportion of Pt4+ shows broadband photoluminescence with a lifetime on the microsecond timescale. A Cs2PtxSn1−xCl6 solid solution with a small amount of Pt4+ substitution exhibits photocatalytic hydrogen evolution activity. An optical spectroscopy study reveals that the switch between photoluminescence and photocatalysis functions is controlled by sub-band gap states. Our finding provides a new way to develop lead-free multifunctional halide perovskites with high stability.
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| 8. |
- Baumgartner, D., et al.
(författare)
-
INFLUENCE OF HEAD ROTATIONAL ACCELERATION PULSE SHAPE ON BRAIN TISSUE STRAINS
- 2014
-
Ingår i: Journal of Neurotrauma. - 0897-7151. ; 31:12
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Brain tolerance to rotational acceleration is relevant for understanding injury thresholds and development of injury mitigation techniques for automobiles and sporting events. This computational-modeling study outlined effects of head rotational acceleration pulse shape on strains within brain tissues. A detailed finite element model of the human skull and brain was developed and validated previously. The model was exercised using realistic rotational accelerations with different magnitude and duration characteristics, and the principal strain re- sponse was extracted for parietal cortex, hippocampus, thalamus, and hypothalamus. Rotational acceleration magnitude was varied to three levels: 3.6krad/s 2 (M1), 5.3krad/s 2 (M2), and 6.6krad/s 2 (M3). Duration was varied to 9msec (D1), 18msec (D2), and 27msec (D3). Hippocampus and hypothalamus sustained more strain than cortex and thalamus. With increasing acceleration magnitude from M1 to M2 and M2 to M3, strain in all brain regions was uniformly increased by 42% and 80%. However, strains demonstrated regionally dependent chan- ges with increasing duration (D1 to D3): 68%, 37%, 33% and 14% in parietal cortex, hippocampus, thalamus and hypothalamus, respec- tively. The trend was consistent for all acceleration magnitudes. This study demonstrated differing and independent effects of rotational acceleration magnitude and duration on strains within brain tissues during rotational acceleration. Magnitude has long been a correlate of injury severity and this study supports that finding in that increased acceleration magnitudes led to uniformly higher brain tissue strains (higher injury risk). However, rotational acceleration duration chan- ged the strain distribution within the brain, resulting in different injury risks in different brain regions. This finding is significant as changing strain distribution with different durations can manifest as different injury distributions within the brain and different neuropsychological outcomes following exposure to head rotational acceleration.
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| 9. |
- Chen, Junsheng, et al.
(författare)
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Photostability of the Oleic Acid-Encapsulated Water-Soluble CdxSeyZn1-xS1-y Gradient Core-Shell Quantum Dots
- 2017
-
Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 2:5, s. 1922-1929
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Tidskriftsartikel (refereegranskat)abstract
- Composite systems where quantum dots (QDs) are combined with other nanomaterials (e.g., gold nanorods) in aqueous solutions have attracted broad attention - both for their potential in applications and for studies of fundamental processes. However, high-quality QDs are typically prepared in organic solvents, and the transfer of QDs to an aqueous phase is needed to create the desired QD composites. Photostability of the transferred QDs - both the steady-state and photo-induced dynamic properties - is essential for studying the processes in the composites and for their applications. We present a detailed study of the photostability of aqueous CdxSeyZn1-xS1-y gradient core-shell QDs obtained by various approaches using linker exchange and surfactant encapsulation. Beside the steady-state photoluminescence (PL) emission stability, we also study changes in the PL decay. From the variety of the studied samples, the water-soluble QDs encapsulated by a double layer of oleic acid show superior properties, that is, stable PL emission and PL decay under continuous light or pulsed-laser light irradiation. We demonstrate that the double-layer encapsulation of QDs can be used to create QDs-metal nanoparticle composites.
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| 10. |
- Haidong, Shao, et al.
(författare)
-
Enhanced deep gated recurrent unit and complex wavelet packet energy moment entropy for early fault prognosis of bearing
- 2020
-
Ingår i: Knowledge-Based Systems. - : Elsevier. - 0950-7051 .- 1872-7409. ; 188
-
Tidskriftsartikel (refereegranskat)abstract
- Early fault prognosis of bearing is a very meaningful yet challenging task to improve the security of rotating machinery. For this purpose, a novel method based on enhanced deep gated recurrent unit and complex wavelet packet energy moment entropy is proposed in this paper. First, complex wavelet packet energy moment entropy is defined as a new monitoring index to characterize bearing performance degradation. Second, deep gated recurrent unit network is constructed to capture the nonlinear mapping relationship hidden in the defined monitoring index. Finally, a modified training algorithm based on learning rate decay strategy is developed to enhance the prognosis capability of the constructed deep model. The proposed method is applied to analyze the simulated and experimental signals of bearing. The results demonstrate that the proposed method is more superior in sensibility and accuracy to the existing methods.
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| 11. |
- Han, Songyu, et al.
(författare)
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End-to-end chiller fault diagnosis using fused attention mechanism and dynamic cross-entropy under imbalanced datasets
- 2022
-
Ingår i: Building and Environment. - : Elsevier. - 0360-1323 .- 1873-684X. ; 212
-
Tidskriftsartikel (refereegranskat)abstract
- Fault diagnosis techniques play an increasingly important role in the operation and maintenance of smart city systems. Artificial intelligence improves the efficiency of chiller system fault diagnosis, and greatly reduces the energy consumption of urban buildings. The existing intelligent fault diagnosis methods of chiller mostly rely on balanced training datasets; lacking fault samples makes these methods incompetent to extract reliable features to recognize abnormal machine conditions, resulting in the degraded performance. To overcome the deficiencies of reported studies, a new method, called end-to-end chiller fault diagnosis, is proposed using a fused attention mechanism and dynamic cross-entropy. Firstly, a one-dimensional convolution network (1D-CNN) and long-short term memory (LSTM) are combined to capture the spatial-temporal features from the original data directly. Afterwards, a fused attention mechanism is developed to further refine the extracted features to increase the contribution of crucial features and achieve high-quality diagnostic information mining. Finally, the dynamic cross-entropy (DCE) is designed for updating the imbalance factor in real-time, with more focus on the hard-classified types. The experimental analysis results demonstrate the feasibility and superiority of the proposed method in identifying chiller system faults with imbalanced datasets.
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| 12. |
- Hanzén, Sarah, et al.
(författare)
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Lifespan Control by Redox-Dependent Recruitment of Chaperones to Misfolded Proteins
- 2016
-
Ingår i: Cell. - : Elsevier BV. - 0092-8674. ; 166:1, s. 140-151
-
Tidskriftsartikel (refereegranskat)abstract
- Caloric restriction (CR) extends the lifespan of flies, worms, and yeast by counteracting age-related oxidation of H2O2-scavenging peroxiredoxins (Prxs). Here, we show that increased dosage of the major cytosolic Prx in yeast, Tsa1, extends lifespan in an Hsp70 chaperone-dependent and CR-independent manner without increasing H2O2 scavenging or genome stability. We found that Tsa1 and Hsp70 physically interact and that hyperoxidation of Tsa1 by H2O2 is required for the recruitment of the Hsp70 chaperones and the Hsp104 disaggregase to misfolded and aggregated proteins during aging, but not heat stress. Tsa1 counteracted the accumulation of ubiquitinated aggregates during aging and the reduction of hyperoxidized Tsa1 by sulfiredoxin facilitated clearance of H2O2-generated aggregates. The data reveal a conceptually new role for H2O2 signaling in proteostasis and lifespan control and shed new light on the selective benefits endowed to eukaryotic peroxiredoxins by their reversible hyperoxidation.
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| 13. |
- He, Yanmei, et al.
(författare)
-
Nature of Self-Trapped Exciton Emission in Zero-Dimensional Cs2ZrCl6 Perovskite Nanocrystals
- 2023
-
Ingår i: The Journal of Physical Chemistry Letters. - 1948-7185. ; 14:34, s. 7665-7671
-
Tidskriftsartikel (refereegranskat)abstract
- Low dimensional perovskite-inspired materials with self-tapped exciton (STE) emission have stimulated a surge of cutting-edge research in optoelectronics. Despite numerous efforts on developing versatile low-dimensional perovskite-inspired materials with efficient STE emissions, there is little emphasis on the intrinsic dynamics of STE-based broad emission in these materials. Here, we investigated the excited state dynamics in zero-dimensional (0D) Cs2ZrCl6 nanocrystals (NCs) with efficient blue STE emission. By using femtosecond transient absorption (fs-TA) spectroscopy, the ultrafast STE formation process within 400 fs is directly observed. Then, the formed STEs relax to an intermediate STE state with a lifetime of ∼180 ps before reaching the emissive STE state with a lifetime of ∼15 μs. Our work offers a comprehensive and precise dynamic picture of STE emission in low-dimensional metal halides and sheds light on extending their potential applications.
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| 14. |
- He, Zhiyi, et al.
(författare)
-
Deep transfer multi-wavelet auto-encoder for intelligent fault diagnosis of gearbox with few target training samples
- 2020
-
Ingår i: Knowledge-Based Systems. - : Elsevier. - 0950-7051 .- 1872-7409. ; 191
-
Tidskriftsartikel (refereegranskat)abstract
- Lack of typical fault samples remains a huge challenge for intelligent fault diagnosis of gearbox. In this paper, a novel approach named deep transfer multi-wavelet auto-encoder is presented for gearbox intelligent fault diagnosis with few training samples. Firstly, new-type deep multi-wavelet auto-encoder is designed for learning important features of the collected vibration signals of gearbox. Secondly, high-quality auxiliary samples are selected based on similarity measure to well pre-train a source model sharing similar characteristics with the target domain. Thirdly, parameter knowledge acquired from the source model is transferred to target model using very few target training samples. Transfer diagnosis cases for different fault severities and compound faults of gearbox confirm the feasibility of the proposed approach even if the working conditions have significant changes.
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| 15. |
- He, Zhiyi, et al.
(författare)
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Kernel flexible and displaceable convex hull based tensor machine for gearbox fault intelligent diagnosis with multi-source signals
- 2020
-
Ingår i: Measurement. - : Elsevier. - 0263-2241 .- 1873-412X. ; 163
-
Tidskriftsartikel (refereegranskat)abstract
- The methods based on traditional pattern recognition and deep learning have been successfully applied in gearbox intelligent diagnosis. However, traditional pattern recognition methods cannot directly classify feature tensors of multi-source signals, and deep learning networks hardly handle the classification of small samples. Therefore, for the gearbox intelligent diagnosis with multi-source signals, a novel tensor classifier called kernel flexible and displaceable convex hull based tensor machine (KFDCH-TM) is proposed. In KFDCH-TM, the kernel flexible and displaceable convex hull of tensor samples in tensor feature space is defined firstly. Then, an optimal separating hyper-plane between two kernel flexible and displaceable convex hulls is constructed. Meanwhile, feature tensors extracted from multi-source signals through wavelet packet transform (WPT) are used to diagnose gearbox fault by KFDCH-TM. The results of two cases demonstrate that KFDCH-TM can effectively identify gearbox fault with multi-source signals and has better robustness.
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| 16. |
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| 17. |
- Nyström, Thomas, 1960, et al.
(författare)
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Peroxiredoxins, gerontogenes linking aging to genome instability and cancer
- 2012
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Ingår i: Genes & Development. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 26:18, s. 2001-2008
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Tidskriftsartikel (refereegranskat)abstract
- Age is the highest risk factor known for a large number of maladies, including cancers. However, it is unclear how aging mechanistically predisposes the organism to such diseases and which gene products are the primary targets of the aging process. Recent studies suggest that peroxiredoxins, antioxidant enzymes preventing tumor development, are targets of age-related deterioration and that bolstering their activity (e.g., by caloric restriction) extends cellular life span. This review focuses on how the peroxiredoxin functions (i.e., as peroxidases, signal transducers, and molecular chaperones) fit with contemporary theories of aging and whether peroxiredoxins could be targeted therapeutically in the treatment of age-associated cancers.
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| 18. |
- Rodilla, Helena, 1982, et al.
(författare)
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Applying THz Technology in Life Science
- 2014
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Ingår i: Swedish Microwave Days. Gigahertz Symposium, March 11-12, 2014. Gothenburg, Sweden.
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Konferensbidrag (refereegranskat)abstract
- Bio-molecules, due to their structure and size, have vibrational and rotational resonances at THz frequencies (0.1 to 10 THz) [1]. This unique interaction promises a multitude of applications in life sciences, wherein the latest development of THz sources and detectors has enabled this field of research to grow. Although being at an early and mostly exploratory stage of development, this field is riddled with many challenges that should be overcome; measurements of inhomogeneous media, short interaction lengths with few molecules, strong water absorption, and also the cultural gap between medical and engineering communities. In this work we present our preliminary results for three experiments within this field.
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| 19. |
- Yang, Bin, et al.
(författare)
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High Resolution Mapping of Two-Photon Excited Photocurrent in Perovskite Microplate Photodetector
- 2018
-
Ingår i: Journal of Physical Chemistry Letters. - : American Chemical Society (ACS). - 1948-7185. ; 9:17, s. 5017-5022
-
Tidskriftsartikel (refereegranskat)abstract
- We fabricate photodetectors based on solution-processed single CH3NH3PbBr3 microcrystals (MCs) and map the two-photon absorption (TPA) excited photocurrent (PC) with spatial resolution of 1 μm. We find that the charge carrier transport length in the MCs depends on the applied electric field, and increases from 5.7 μm for 0.02 V bias (dominated by carrier diffusion) to 23.2 μm for 2 V bias (dominated by carrier drift). Furthermore, PC shows strong spatial variations. Combining the PC mapping results with time-resolved photoluminescence microscopy, we demonstrate that the spatial distribution of PC mainly originates from the inhomogeneous distribution of trap-states across perovskite MCs. This suggests that there is still large margin for improvement of perovskite single crystal devices by better controlling of the traps.
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| 20. |
- Yang, Jin, et al.
(författare)
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Climatic Forcing of Plio-Pleistocene Formation of the Modern Limpopo River, South Africa
- 2021
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Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 48:14
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the evolution of river systems in southern Africa is fundamental to constrain the evolution of landscape and sediment dispersal patterns. It is widely considered that the upper Zambezi River was connected with the Limpopo River during the Cretaceous, forming what was then the largest river in Africa. Crustal flexure during the Paleogene severed the upper Zambezi drainage from the Limpopo, setting the framework of the modern Zambezi and Limpopo River systems. We present first evidence-based on heavy-mineral assemblages from cores drilled offshore of the Limpopo River mouth and samples collected in different reaches of the modern Limpopo River, integrated with magnetic susceptibility, detrital-zircon geochronology, and geomorphological analysis-suggesting that the current Limpopo River formed recently in the Plio-Quaternary. Plio-Quaternary climate change is envisaged to have controlled the recent dynamics of river drainage and consequent distribution of sediment loads, as observed in many other transcontinental rivers worldwide.
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| 21. |
- Yang, Junsheng, et al.
(författare)
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Spatial sequestration and detoxification of Huntingtin by the ribosome quality control complex
- 2016
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Ingår i: Elife. - 2050-084X. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Huntington disease (HD) is a neurological disorder caused by polyglutamine expansions in mutated Huntingtin (mHtt) proteins, rendering them prone to form inclusion bodies (IB). We report that in yeast, such IB formation is a factor-dependent process subjected to age related decline. A genome-wide, high-content imaging approach, identified the E3 ubiquitin ligase, Ltn1 of the ribosome quality control complex (RQC) as a key factor required for IB formation, ubiquitination, and detoxification of model mHtt. The failure of Itn1 Delta cells to manage mHtt was traced to another RQC component, Tae2, and inappropriate control of heat shock transcription factor, Hsf1, activity. Moreover, super-resolution microscopy revealed that mHtt toxicity in RQC-deficient cells was accompanied by multiple mHtt aggregates altering actin cytoskeletal structures and retarding endocytosis. The data demonstrates that spatial sequestration of mHtt into IBs is policed by the RQC-Hsf1 regulatory system and that such compartmentalization, rather than ubiquitination, is key to mHtt detoxification.
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| 22. |
- Zheng, Ju, et al.
(författare)
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Role of the ribosomal quality control machinery in nucleocytoplasmic translocation of polyQ-expanded huntingtin exon-1
- 2017
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 0006-291X. ; 493:1, s. 708-717
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Tidskriftsartikel (refereegranskat)abstract
- The subcellular localization of polyQ-expanded huntingtin exon1 (Httex1) modulates polyQ toxicity in models of Huntington's disease. Using genome-wide screens in a yeast model system, we report that the ribosome quality control (RQC) machinery, recently implicated in neurodegeneration, is a key determinant for the nucleocytoplasmic distribution of Httex1-103Q, Deletion of the RQC genes, LTN1 or RQC1, caused the accumulation of Httex1-103Q in the nucleus through a process that required the CAT-tail tagging activity of Rqc2 and transport via the nuclear pore complex. We provide evidence that nuclear accumulation of Httex1-103Q enhances its cytotoxicity, suggesting that the RQC machinery plays an important role in protecting cells against the adverse effects of polyQ expansion proteins. (C) 2017 The Authors. Published by Elsevier Inc.
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| 23. |
- Zhiyi, He, et al.
(författare)
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Transfer fault diagnosis of bearing installed in different machines using enhanced deep auto-encoder
- 2020
-
Ingår i: Measurement. - : Elsevier. - 0263-2241 .- 1873-412X. ; 152
-
Tidskriftsartikel (refereegranskat)abstract
- The collected vibration data with labeled information from bearing is far insufficient in engineering practice, which is challenging for training an intelligent diagnosis model. For this purpose, enhanced deep transfer auto-encoder is proposed for fault diagnosis of bearing installed in different machines. First, scaled exponential linear unit is used to improve the quality of the mapped vibration data collected from bearing. Second, nonnegative constraint is adopted for modifying the loss function to improve reconstruction effect. Then, the parameter knowledge of the well-trained source model is transferred to the target model. Finally, target training samples with limited labeled information are adopted for fine-tuning the target model to match the characteristics of the target testing samples. The proposed approach is applied for analyzing the measured vibration signals of bearings installed in different machines. The analysis results show that the proposed approach holds better transfer diagnosis performance compared with the existing approaches.
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| 24. |
- Zhu, Xuefeng, et al.
(författare)
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Mediator tail subunits can form amyloid-like aggregates in vivo and affect stress response in yeast
- 2015
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 43:15, s. 7306-7314
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Tidskriftsartikel (refereegranskat)abstract
- The Med2, Med3 and Med15 proteins form a heterotrimeric subdomain in the budding yeast Mediator complex. This Med15 module is an important target for many gene specific transcription activators. A previous proteome wide screen in yeast identified Med3 as a protein with priogenic potential. In the present work, we have extended this observation and demonstrate that both Med3 and Med15 form amyloid-like protein aggregates under H2O2 stress conditions. Amyloid formation can also be stimulated by overexpression of Med3 or of a glutamine-rich domain present in Med15, which in turn leads to loss of the entire Med15 module from Mediator and a change in stress response. In combination with genome wide transcription analysis, our data demonstrate that amyloid formation can change the subunit composition of Mediator and thereby influence transcriptional output in budding yeast.
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