A fundamental understanding of hot-carrier dynamics in photo-excited metal nanostructures is needed to unlock their potential for photodetection and photocatalysis. Despite numerous studies on the ...ultrafast dynamics of hot electrons, so far, the temporal evolution of hot holes in metal-semiconductor heterostructures remains unknown. Here, we report ultrafast (t < 200 fs) hot-hole injection from Au nanoparticles into the valence band of p-type GaN. The removal of hot holes from below the Au Fermi level is observed to substantially alter the thermalization dynamics of hot electrons, reducing the peak electronic temperature and the electron-phonon coupling time of the Au nanoparticles. First-principles calculations reveal that hot-hole injection modifies the relaxation dynamics of hot electrons in Au nanoparticles by modulating the electronic structure of the metal on timescales commensurate with electron-electron scattering. These results advance our understanding of hot-hole dynamics in metal-semiconductor heterostructures and offer additional strategies for manipulating the dynamics of hot carriers on ultrafast timescales.
Understanding ecological niches of major tick species and prevalent tick-borne pathogens is crucial for efficient surveillance and control of tick-borne diseases. Here we provide an up-to-date review ...on the spatial distributions of ticks and tick-borne pathogens in China. We map at the county level 124 tick species, 103 tick-borne agents, and human cases infected with 29 species (subspecies) of tick-borne pathogens that were reported in China during 1950-2018. Haemaphysalis longicornis is found to harbor the highest variety of tick-borne agents, followed by Ixodes persulcatus, Dermacentor nutalli and Rhipicephalus microplus. Using a machine learning algorithm, we assess ecoclimatic and socioenvironmental drivers for the distributions of 19 predominant vector ticks and two tick-borne pathogens associated with the highest disease burden. The model-predicted suitable habitats for the 19 tick species are 14‒476% larger in size than the geographic areas where these species were detected, indicating severe under-detection. Tick species harboring pathogens of imminent threats to public health should be prioritized for more active field surveillance.
Tree shrews have a close relationship to primates and have many advantages over rodents in biomedical research. However, the laek of gene manipulation methods has hindered the wider use of this ...animal. Spermatogonial stem cells （SSCs） have been successfully expanded in culture to permit sophisticated gene editing in the mouse and rat. Here, we describe a culture system for the long-term expansion of tree shrew SSCs without the loss of stem cell properties. In our study, thymus cell antigen 1 was used to enrich tree shrew SSCs. RNA-sequencing analysis revealed that the Wnt/β-catenin signaling pathway was active in undifferentiated SSCs, but was downregulated upon the initiation of SSC differentiation. Exposure of tree shrew primary SSCs to recombinant Wnt3a protein during the initial passages of culture enhanced the survival of SSCs. Use of tree shrew Sertoli cells, but not mouse embryonic fibroblasts, as feeder was found to be necessary for tree shrew SSC proliferation, leading to a robust cell expansion and long-term culture. The expanded tree shrew SSCs were transfected with enhanced green fluorescent protein （EGFP）-expressing lentiviral vectors. After transplantation into sterilized adult male tree shrew＇s testes, the EGFP-tagged SSCs were able to restore spermatogenesis and successfully generate transgenic offspring. Moreover, these SSCs were suitable for the CRISPR/Cas9-mediated gene modification. The development of a culture system to expand tree shrew SSCs in combination with a gene editing approach paves the way for precise genome manipulation using the tree shrew.
Although the substitution of Cu by Ag to suppress CuZn defects offers several advantages in overcoming the large open-circuit voltage (Voc) deficit for Cu2ZnSn(S,Se)4 (CZTSSe) solar cells, an ...excellent performance has not been achieved to date primarily due to the Fermi level pinning at the CdS/absorber interface and large recombination at the absorber/Mo interface. Herein, we developed a composition grading strategy to achieve a V-shaped Ag-graded structure with a higher Ag content on both the back and front surfaces of the (Cu,Ag)2ZnSn(S,Se)4 (CAZTSSe) layer. The key advantages of this Ag-graded structure are as follows: the higher content towards the CdS/absorber interface can create weak n-type donor defects and retard Fermi level pinning, whereas the lower content at the interlayer maintains the conductivity and light absorption; moreover, the other higher content towards Mo back contact can effectively suppress the recombination and improve the utilization of long-wave incident light. By appropriately adjusting the Ag gradient, we demonstrated a significant increase in Voc, and an unexpected conversion efficiency of 11.2% was achieved. This is the highest efficiency achieved to date for Ag-substituted CZTSSe solar cells, and the result supports a new aspect that synthesis of a composition-graded CAZTSSe absorber has great potential for future research.
•A coprecipitation method was applied to fabricate BiOBr/MIL-53(Fe) novel photocatalyst.•The MIL-53(Fe) doping endowed BiOBr with the stronger adsorption ability and higher utilization efficiency of ...visible light.•The heterojunction can be formed between MIL-53(Fe) and BiOBr to enhance the photocatalytic degradation performance.•The degradation pathway of carbamazepine was put forward based on the experimental results.
In this work, a series of BiOBr/MIL-53(Fe) hybrid photocatalysts have prepared by a facile co-precipitation method. Rhodamine B (RhB) and carbamazepine (CBZ) were selected as the targets to evaluate the visible-light photocatalytic activity of the prepared samples. All of the hybrids exhibited better catalytic performance compared to the pristine BiOBr, and the performance of BiOBr/MIL-53 (with 20 wt% of MIL-53) was the most efficient. The excellent performance can be contributed to the incorporation of MIL-53(Fe) which not only form the heterojunction with BiOBr to inhibit the recombination of the photoinduced electron-hole pairs, but also utilize the visible light more effectively. The photocatalytic mechanism was studied, it shows that OH and h+ were both the main active species for the degradation of contaminants. Moreover, the degradation pathways of CBZ via the photocatalysis over BiOBr/MIL-53(Fe) hybrid were presented based on the determination of LC–MS/MS and the results of catalytic mechanisms. With the recent increase in reported MOFs materials, we believe a new class of hybrid catalytic materials is possible. This result is conceptually interesting as it opens the door to various MOF-based BiOBr materials for environmental purification and restoration.
Introduction
Daytime napping is frequently seen in older adults. The longitudinal relationship between daytime napping and cognitive aging is unknown.
Methods
Using data from 1401 participants of the ...Rush Memory and Aging Project, we examined the longitudinal change of daytime napping inferred objectively by actigraphy, and the association with incident Alzheimer's dementia during up to 14‐year follow‐up.
Results
Older adults tended to nap longer and more frequently with aging, while the progression of Alzheimer's dementia accelerates this change by more than doubling the annual increases in nap duration/frequency. Longer and more frequent daytime naps were associated with higher risk of Alzheimer's dementia. Interestingly, more excessive (longer or more frequent) daytime napping was correlated with worse cognition a year later, and conversely, worse cognition was correlated with more excessive naps a year later.
Discussion
Excessive daytime napping and Alzheimer's dementia may possess a bidirectional relationship or share common pathophysiological mechanisms.
As a key immune cell in the brain, microglia are essential for protecting the central nervous system (CNS) from viral infections, including HIV. Microglia possess functional Toll‐like receptor 3 ...(TLR3), a key viral sensor for activating interferon (IFN) signaling pathway‐mediated antiviral immunity. We, therefore, studied the effect of poly (I:C), a synthetic ligand of TLR3, on the activation of the intracellular innate immunity against HIV in human iPSC‐derived microglia (iMg). We found that poly (I:C) treatment of iMg effectively inhibits HIV infection/replication at both mRNA and protein levels. Investigations of the mechanisms revealed that TLR3 activation of iMg by poly (I:C) induced the expression of both type I and type III IFNs. Compared with untreated cells, the poly (I:C)‐treated iMg expressed significantly higher levels of IFN‐stimulated genes (ISGs) with known anti‐HIV activities (ISG15, MxB, Viperin, MxA, and OAS‐1). In addition, TLR3 activation elicited the expression of the HIV entry coreceptor CCR5 ligands (CC chemokines) in iMg. Furthermore, the transcriptional profile analysis showed that poly (I:C)‐treated cells had the upregulated IFN signaling genes (ISG15, ISG20, IFITM1, IFITM2, IFITM3, IFITM10, APOBEC3A, OAS‐2, MxA, and MxB) and the increased CC chemokine signaling genes (CCL1, CCL2, CCL3, CCL4, and CCL15). These observations indicate that TLR3 is a potential therapy target for activating the intracellular innate immunity against HIV infection/replication in human microglial cells. Therefore, further studies with animal models and clinical specimens are necessary to determine the role of TLR3 activation‐driven antiviral response in the control and elimination of HIV in infected host cells.
Summary
Rice grain filling rate contributes largely to grain productivity and accumulation of nutrients. MicroRNAs (miRNAs) are key regulators of development and physiology in plants and become a ...novel key target for engineering grain size and crop yield. However, there is little studies, so far, showing the miRNA regulation of grain filling and rice yield, in consequence. Here, we show that suppressed expression of rice miR1432 (STTM1432) significantly improves grain weight by enhancing grain filling rate and leads to an increase in overall grain yield up to 17.14% in a field trial. Molecular analysis identified rice Acyl‐CoA thioesterase (OsACOT), which is conserved with ACOT13 in other species, as a major target of miR1432 by cleavage. Moreover, overexpression of miR1432‐resistant form of OsACOT (OXmACOT) resembled the STTM1432 plants, that is, a large margin of an increase in grain weight up to 46.69% through improving the grain filling rate. Further study indicated that OsACOT was involved in biosynthesis of medium‐chain fatty acids. In addition, RNA‐seq based transcriptomic analyses of transgenic plants with altered expression of miR1432 demonstrated that downstream genes of miR1432‐regulated network are involved in fatty acid metabolism and phytohormones biosynthesis and also overlap with the enrichment analysis of co‐expressed genes of OsACOT, which is consistent with the increased levels of auxin and abscisic acid in STTM1432 and OXmACOT plants. Overall, miR1432‐OsACOT module plays an important role in grain filling in rice, illustrating its capacity for engineering yield improvement in crops.
Hair follicle stem cells (HFSCs) regenerate hair in response to Wnt signalling. Here, we unfold genome-wide transcriptional and chromatin landscapes of β-catenin-TCF3/4-TLE circuitry, and genetically ...dissect their biological roles within the native HFSC niche. We show that during HFSC quiescence, TCF3, TCF4 and TLE (Groucho) bind coordinately and transcriptionally repress Wnt target genes. We also show that β-catenin is dispensable for HFSC viability, and if TCF3/4 levels are sufficiently reduced, it is dispensable for proliferation. However, β-catenin is essential to activate genes that launch hair follicle fate and suppress sebocyte fate determination. TCF3/4 deficiency mimics Wnt-β-catenin-dependent activation of these hair follicle fate targets; TCF3 overexpression parallels their TLE4-dependent suppression. Our studies unveil TCF3/4-TLE histone deacetylases as a repressive rheostat, whose action can be relieved by Wnt-β-catenin signalling. When TCF3/4 and TLE levels are high, HFSCs can maintain stemness, but remain quiescent. When these levels drop or when Wnt-β-catenin levels rise, this balance is shifted and hair regeneration initiates.
Dysregulation of non-coding RNAs, including miRNAs and lncRNAs has been reported to play vital roles in gastric cancer (GC) carcinogenesis, but the mechanism involved is largely unknown. Using the ...cancer genome atlas (TCGA) data set and bioinformatics analyses, we identified miR-532-5p as a potential tumor suppressor in GC, and found that lncRNA LINC01410 might be a negative regulator of miR-532-5p. We then conducted a series of in vivo and in vitro assays to explore the effect of LINC01410 on miR-532-5p-mediated GC malignancy and the underlying mechanism involved. MiR-532-5p overexpression inhibited GC metastasis and angiogenesis in vitro and in vivo, whereas miR-532-5p silencing had the opposite effect. Further study showed that miR-532-5p attenuated NF-κB signaling by directly inhibiting NCF2 expression, while miR-532-5p silencing in GC enhanced NF-κB activity. Furthermore, we demonstrated miR-532-5p down-regulation was caused by aberrantly high expression of LINC01410 in GC. Mechanistically, overexpression of LINC01410 promoted GC angiogenesis and metastasis by binding to and suppressing miR-532-5p, which resulted in up-regulation of NCF2 and sustained NF-κB pathway activation. Interestingly, NCF2 could in turn increase the promoter activity and expression of LINC01410 via NF-κB, thus forming a positive feedback loop that drives the malignant behavior of GC. Finally, high expression of LINC01410, along with low expression of miR-532-5p, was associated with poor survival outcome in GC patients. Our studies uncover a mechanism for constitutive LINC1410-miR-532-5p-NCF2-NF-κB feedback loop activation in GC, and consequently, as a potential therapeutic target in GC treatment.
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