Chlorophyllase is transcriptionally regulated by CsMYB308/CsDOF3 in young leaves of tea plant

Chlorophyll contributes to tea coloration, which is an important factor in tea quality. Chlorophyll metabolism is induced by light, but the transcriptional regulation responsible for light-induced chlorophyll metabolism is largely unknown in tea leaves. Here, we characterized a chlorophyllase1 gene CsCLH1 from young tea leaves and showed it is essential for chlorophyll metabolism, using transient overexpression and silencing in tea leaves and ectopic overexpression in Arabidopsis. CsCLH1 was significantly induced by high light. The DOF protein CsDOF3, an upstream direct regulator of CsCLH1, was also identified. Acting as a nuclear-localized transcriptional factor, CsDOF3 responded for light and repressed CsCLH1 transcription and increased chlorophyll content by directly binding to the AAAG cis-element in the CsCLH1 promoter. CsDOF3was able to physically interact with the R2R3-MYB transcription factor CsMYB308 and interfere with transcriptional activity of CsCLH1. In addition, CsMYB308 binds to the CsCLH1 promoter to enhance CsCLH1 expression and decrease chlorophyll content. CsMYB308 and CsDOF3 act as an antagonistic complex to regulate CsCLH1 transcription and chlorophyll in young leaves. Collectively, the study adds to the understanding of the transcriptional regulation of chlorophyll in tea leaves in response to light and provides a basis for improving the appearance of tea.

Reconstructing proton channels via Zr-MOFs realizes highly ion-selective and proton-conductive SPEEK-based hybrid membrane for vanadium flow battery

There is an urgent need to break through the trade-off between proton conductivity and ion selectivity of proton exchange membrane(PEM)in vanadium flow battery(VFB).Proton channels in PEM are the key to controlling the ion sieving and proton conductivity in VFB.Herein,two types of proton channels are reconstructed in the hybrid membrane via introducing modified Zr-MOFs(IM-UIO-66-AS)into SPEEK matrix.Internal proton channels in IM-UIO-66-AS and interfacial proton channels between grafted imidazole groups on Zr-MOFs and SPEEK greatly improve the conductivity of the IM-UIO-66-AS/SPEEK hybrid membrane.More importantly,both reconstructed proton channels block the vanadium-ion permeation to realize enhanced ion selectivity according to the size sieving and Donnan exclusion effects,respectively.Moreover,the hybrid membrane exhibits good mechanical property and dimensional stability.Benefiting from such rational design,a VFB loading with the optimized membrane exhibits enhanced voltage efficiency of 79.9%and outstanding energy efficiency of 79.6%at 200 m A cm^(-2),and keeps a notable cycle stability for 300 cycles in the long-term cycling test.Therefore,this study provides inspiration for preparing next-generation PEMs with high ion selectivity and proton conductivity for VFB application.

AZD1775 and anti-PD-1 antibody synergistically sensitize hepatoma to radiotherapy

Background:Radiation(IR)-induced DNA damage triggers cell cycle arrest and has a suppressive effect on the tumor microenvironment(TME).Wee1,a cell cycle regulator,can eliminate G2/M arrest by phosphorylating cyclin-dependent kinase 1(CDK1).Meanwhile,programed death-1/programed death ligand-1(PD-1/PDL-1)blockade is closely related to TME.This study aims to investigate the effects and mechanisms of Wee1 inhibitor AZD1775 and anti-PD-1 antibody(anti-PD-1 Ab)on radiosensitization of hepatoma.Methods:The anti-tumor activity of AZD1775 and IR was determined by 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide(MTT)assay on human and mouse hepatoma cells HepG2,Hepa1-6,and H22.The anti-hepatoma mechanism of AZD1775 and IR revealed by flow cytometry and Western blot in vitro.A hepatoma subcutaneous xenograft mice model was constructed on Balb/c mice,which were divided into control group,IR group,AZD1775 group,IR+AZD1775 group,IR+anti-PD-1 Ab group,and the IR+AZD1775+anti-PD-1 Ab group.Cytotoxic CD8^(+)T cells in TME were analyzed by flow cytometry.Results:Combining IR with AZD1775 synergistically reduced the viability of hepatoma cells in vitro.AZD1775 exhibited antitumor effects by decreasing CDK1 phosphorylation to reverse the IR-induced G2/M arrest and increasing IR-induced DNA damage.AZD1775 treatment also reduced the proportion of PD-1^(+)/CD8^(+)T cells in the spleen of hepatoma subcutaneous xenograft mice.Further studies revealed that AZD1775 and anti-PD-1 Ab could enhance the radiosensitivity of hepatoma by enhancing the levels of interferonγ(IFNγ)^(+)or Ki67^(+)CD8 T cells and decreasing the levels of CD8^(+)Tregs cells in the tumor and spleen of the hepatoma mice model,indicating that the improvement of TME was manifested by increasing the cytotoxic factor IFNγexpression,enhancing CD8^(+)T cells proliferation,and weakening CD8^(+)T cells depletion.Conclusions:This work suggests that AZD1775 and anti-PD-1 Ab synergistically sensitize hepatoma to radiotherapy by enhancing IR-induced DNA damage and improving cytotoxic CD8^(+)T cells in TME.

Primary cilia restrict autoinflammation by mediating PD-L1 expression

Ciliopathies are multisystem disorders characterized by the dysfunction of motile and/or non-motile cilia,which are microtubule-based structures protruding from the cell surface and function in cell motility and signaling.Common clinical manifestations of ciliopathies include retinal degeneration,mental retardation,renal abnormality,obesity,and skeletal dysplasia[1,2].Fibrosis of vital organs,characterized by the extensive deposition of extracellular matrix components,represents another complication frequently observed in patients and animal models of ciliopathies[3].

Embryonic stem cell-derived extracellular vesicles rejuvenate senescent cells and antagonize aging in mice

Aging is a degenerative process that leads to tissue dysfunction and death.Embryonic stem cells(ESCs)have great therapeutic potential for age-related diseases due to their capacity for self-renewal and plasticity.However,the use of ESCs in clinical treatment is limited by immune rejection,tumourigenicity and ethical issues.ESC-derived extracellular vesicles(EVs)may provide therapeutic effects that are comparable to those of ESCs while avoiding unwanted effects.Here,we fully evaluate the role of ESC-EVs in rejuvenation in vitro and in vivo.Using RNA sequencing(RNA-Seq)and microRNA sequencing(miRNA-Seq)screening,we found that miR-15b-5p and miR-290a-5p were highly enriched in ESC-EVs,and induced rejuvenation by silencing the Ccn2-mediated AKT/mTOR pathway.These results demonstrate that miR-15b-5p and miR-290a-5p function as potent activators of rejuvenation mediated by ESC-EVs.The rejuvenating effect of ESC-EVs was further investigated in vivo by injection into aged mice.The results showed that ESC-EVs successfully ameliorated the pathological age-related phenotypes and rescued the transcriptome profile of aged mice.Our findings demonstrate that ESC-EVs treatment can rejuvenate senescence both in vitro and in vivo and suggest the therapeutic potential of ESC-EVs as a novel cell-free alternative to ESCs for age-related diseases.

Ce-doped MIL-125-NH_(2)coupled Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators for thermo-enhanced photocatalytic oxidative desulfurization

Photocatalytic oxidative desulfurization(PODS)over efficient earth-abundant catalysts to obtain clean fuel oil is of great importance for the environmental protection.In this work,a series of Ce-doped MIL-125-NH_(2)photocatalysts were successfully prepared via a simple in-situ doping method and exhibited superior PODS performance of dibenzothiophene(DBT)under mild reaction conditions.The 1.0 mol%Ce/MIL-125-NH_(2)catalyst achieved 100%sulfur removal within 22 min at 30℃ under visible light illumination,which is mainly attributed to the high surface area and the formation of Ce-Ti-oxo clusters due to electronic coupling.The valence transformation of Ce^(4+)/Ce^(3+)and Ti^(4+)/Ti^(3+)redox mediators could not only expose abundant Lewis acid sites,but also promote the separation and transfer of photogenerated charges.In addition,increasing the reaction temperature has been demonstrated to be effective in promoting the PODS performance.Additionally,a thermo-enhanced PODS mechanism was proposed over Ce/MIL-125-NH_(2),demonstrating the great potential of thermal energy to promote the desulfurization activity.

Study on the Influencing Factors of“Internet+”Recycling of Waste Mobile Phone Dominated by Retailers

The popularization of smartphones and the acceleration of their replacement lead to a surge in mobile phone disposal.How to recycle waste mobile phones efficiently becomes a major problem in today’s society.The“Internet+”recycling mode is an effective way to solve this problem.The recycling process of waste mobile phones involves retailers,manufacturers,third parties and other recycling parts.Retailers have natural advantages compared with other parts because of their perfect sales network and logistics system.The system dynamics model for“Internet+”recycling of waste mobile phones dominated by retailers is constructed,and the Vensim software is used to simulate the influence of changes in two key factors in“Internet+”recycling environment:Annual operating cost of online platform and offline unit logistics cost on retailers’recycling volume and recycling profit.The results show that the investment of online platform operation cost is conducive to the increase of retailers’online waste mobile phone recycling volume and recycling profit,while the investment of offline logistics cost increases retailers’online waste mobile phone recycling volume,but reduces the recycling profit.

PdAg bimetallic electrocatalyst for highly selective reduction of CO2 with low COOH^* formation energy and facile CO desorption

For electrocatalytic reduction of CO2 to CO,the stabilization of intermediate COOH^* and the desorption of CO^* are two key steps.Pd can easily stabilize COOH^*,whereas the strong CO^* binding to Pd surface results in severe poisoning,thus lowering catalytic activity and stability for CO2 reduction.On Ag surface,CO^* desorbs readily,while COOH^* requires a relatively high formation energy,leading to a high overpotential.In light of the above issues,we successfully designed the PdAg bimetallic catalyst to circumvent the drawbacks of sole Pd and Ag.The PdAg catalyst with Ag-terminated surface not only shows a much lower overpotential(-0.55 V with CO current density of 1 mA/cm^2)than Ag(−0.76 V),but also delivers a CO/H2 ratio 18 times as high as that for Pd at the potential of-0.75 V vs.RHE.The issue of CO poisoning is significantly alleviated on Ag-terminated PdAg surface,with the stability well retained after 4h electrolysis at-0.75 V vs.RHE.Density functional theory(DFT)calculations reveal that the Ag-terminated PdAg surface features a lowered formation energy for COOH^* and weakened adsorption for CO^*,which both contribute to the enhanced performance for CO2 reduction.

Challenges and future directions of secure federated learning:a survey

Federated learning came into being with the increasing concern of privacy security,as people’s sensitive information is being exposed under the era of big data.It is an algorithm that does not collect users’raw data,but aggregates model parameters from each client and therefore protects user’s privacy.Nonetheless,due to the inherent distributed nature of federated learning,it is more vulnerable under attacks since users may upload malicious data to break down the federated learning server.In addition,some recent studies have shown that attackers can recover information merely from parameters.Hence,there is still lots of room to improve the current federated learning frameworks.In this survey,we give a brief review of the state-of-the-art federated learning techniques and detailedly discuss the improvement of federated learning.Several open issues and existing solutions in federated learning are discussed.We also point out the future research directions of federated learning.

Highly dispersed Pt clusters encapsulated in MIL-125-NH_(2) via in situ auto-reduction method for photocatalytic H_(2) production under visible light

Efficient hydrogen production via photocatalysis with high utilization efficiency of Pt cocatalyst is of great importance for sustainable development. In this work, we report an in situ auto-reduction strategy to encapsulate highly dispersed Pt clusters inside the cages of MIL-125-NH_(2). The amino groups in MIL-125-NH_(2) first react with formaldehyde to form reducing groups (i.e.,–NH-CH_(2)OH), which can in situ auto-reduce the confined Pt^(2+) ions to ultrasmall Pt clusters within the cavities. With optimized Pt content, photocatalytic H_(2) production over the obtained Pt(1.5)/MIL-125-NH-CH_(2)OH catalyst with 1.43 wt.% Pt loading achieved as high as 4,496.4 µmol·g^(-1)·h^(-1) under visible light (λ > 420 nm) due to the facilitated transfer and separation of the photo-induced charger carriers arising from the synergetic effects between highly dispersed Pt clusters and MIL-125-NH-CH_(2)OH framework. This in situ auto-reduction strategy may be extended to encapsulate various kinds of metal or alloy clusters/nanoparticles within amino-functioned metal-organic frameworks (MOFs) with superior properties and excellent performance.

Dppa3 is critical for Lin28a-regulated ES cells na?ve–primed state conversion

Lin28a is a pluripotent factor that promotes somatic cell reprogramming. Unlike other pluripotent factors, Lin28a expression is transient and accumulated in primed embryonic stem (ES) cells, but its exact function and mechanism in the conversion of ES cells from naive to primed state remain unclear. Here, we present evidence for Dppa3, a protein originally known for its role in germ cell development, as a downstream target of Lin28a in naive–primed conversion. Using rescue experiment, we demonstrate that Dppa3 functions predominantly downstream of Lin28a during naive–primed state conversion. Higher level of Lin28a prevents let-7 maturation and results in Dnmt3a/b (target of let-7) upregulation, which in turn induces hypermethylation of the Dppa3 promoter. Dppa3 demarcates naive versus primed pluripotency states. These results emphasize that Lin28a plays an important role during the naive–primed state conversion of ES cells, which is partially mediated by a Lin28a–let-7–Dnmt3a/b–Dppa3 axis.

Covalent organic framework stabilized CdS nanoparticles as efficient visible-light-driven photocatalysts for selective oxidation of aromatic alcohols

Noble-metal-free photocatalysts with high and stable performance provide an environmentally-friendly and cost-efficient route for green organic synthesis.In this work,CdS nanoparticles with small particle size and different amount were successfully deposited on the surface of covalent organic frameworks(COFs).The deposition of suitable content of CdS on COFs could not only modify the light adsorption ability and the intrinsic electronic properties,but also enhance the photocatalytic activity and cycling performance of CdS for the selective oxidation of aromatic alcohols under visible light.Especially,COF/CdS-3 exhibited the highest yield(97.1%)of benzalde hyde which is approximately 2.5 and 15.9 times as that of parental CdS and COF,respectively.The results show that the combination of CdS and COF can improve the utilization of visible light and the separation of photo-generated charge carriers,and COF with theπ-conjugated system as supports for CdS nanoparticles could provide efficient electron transport channels and improve the photocatalytic performance.Therefore,this kind of COF-supported photocatalysts with accelerated photo-induced electrons and charge-carrier separation between semiconductors possesses great potentials in future green organic synthesis.

Multi-functional 3D N-doped TiO2 microspheres used as scattering layers for dye-sensitized solar cells

Three-dimensional TiO2 microspheres doped with N were synthesized by a simple single-step solvothermal method and the sample treated for 15 h （hereafter called TMF） was then used as scattering layers in the photoanodes of dye-sensitized solar cells （DSSCs）. The TMF was characterized using scanning electron micro- scopy, high resolution transmission electron microscopy, Brunauer-Emmett-Teller measurements, X-ray diffraction, and X-ray photoelectron spectroscopy. The TMF had a high surface area of 93.2 m2. g-~ which was beneficial for more dye-loading. Five photoanode films with different internal structures were fabricated by printing different numbers of TMF scattering layers on fluorine-doped tin oxide glass. UV-vis diffuse reflection spectra, incident photon-to-current efficiencies, photocurrent-voltage curves and electrochemical impedance spectroscopy were used to investigate the optical and electrochemical proper- ties of these photoanodes in DSSCs. The presence of nitrogen in the TMF changed the TMF microstructure, which led to a higher open circuit voltage and a longer electron lifetime. In addition, the presence of the nitrogen significantly improved the light utilization and photocur- rent. The highest photoelectric conversion efficiency achieved was 8.08%, which is much higher than that derived from typical P25 nanoparticles （6.52%）.

MicroRNAs transcriptionally regulate promoter activity in Arabidopsis thaliana

Micro RNAs(mi RNAs) are vital regulators that repress gene expression in the cytoplasm in two main ways: m RNA degradation and translational inhibition. Several animal studies have shown that mi RNAs also target promoters, thereby activating expression.Whether this mi RNA action also occurs in plants is unknown. In this study, we demonstrated that several mi RNAs regulate target promoters in Arabidopsis thaliana. For example, mi R5658 was predominantly present in the nucleus and activated the expression of AT3 G25290 directly by binding to its promoter. Our observations suggest that this mode of action may be a general feature of plant mi RNAs, and thus provide insight into the vital roles of plant mi RNAs in the nucleus.

A self-assembling prodrug nanosystem to enhance metabolic stability and anticancer activity of gemcitabine

Self-assembly is a powerful approach in molecular engineering for biomedical applications,in particu-lar for creating self-assembling prodrugs.Here,we report a self-assembling prodrug of the anticancer drug gemcitabine(Gem)based on amphiphilic dendrimer approach.The prodrug reported in this study demonstrates high drug loading(40%)and robust ability to self-assemble into small nanomicelles,which increase the metabolic stability of Gem and enable entry into cells via endocytosis,hence bypassing transport-mediated uptake.In addition,this prodrug nanosystem exhibited an effective pH-and enzyme-responsive release of Gem,resulting in enhanced anticancer activity and reduced toxicity.Harboring ad-vantageous features of both prodrug-and nanotechnology-based drug delivery,this self-assembling Gem prodrug nanosystem constitutes a promising anticancer candidate.This study also offers new perspectives of the amphiphilic dendrimer nanoplatforms for the development of self-assembling prodrugs.