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Vernalization is a pivotal stage for some plants involving many epigenetic changes during cold exposure. In Arabidopsis , an essential step in vernalization for further flowering is successful silence the potent floral repressor Flowering Locus C (FLC) by repressing histone mark. At Val1 is a multi-function protein containing five domains that participate into many recognition processes and is validated to recruit the repress histone modifier PHD-PRC2 complex and interact with components of the ASAP complex target to the FLC nucleation region through recognizing a cis element known as CME (cold memory element) by its plant-specific B3 domain. Here, we determine the crystal structure of the B3 domain in complex with Sph/RY motif in CME. Our structural analysis reveals the specific DNA recognition by B3 domain, combined with our in vitro experiments, we provide the structural insight into the important implication of At VAL1-B3 domain in flowering process. [ABSTRACT FROM AUTHOR]

Meiosis is one of the most dramatic differentiation programs accompanied by a striking change in gene expression profiles in fission yeast Schizosaccharomyces pombe . Whereas a number of meiosis-specific transcripts are expressed untimely in mitotic cells, and the entry of meiosis will be blocked as the accumulation of meiosis-specific mRNAs in the mitotic cells. A YTH domain containing protein Mmi1 was identified as a pivotal effector in a post-transcriptional event termed selective elimination of meiosis-specific mRNAs. Mmi1 can recognize and bind a class of meiosis-specific transcripts expressed inappropriately in mitotic cells, which all contain a conservative region called DSR, as a mark to remove them in cooperation with nuclear exosomes. Here we report the 1.6 Å resolution crystal structure of the Mmi1-YTH domain in complex with a high consensus hexanucleotide motif, which is multiple copied in the DSR region. Our structure observations, supported by site-directed mutations of key residues illustrate the mechanism for specific recognition of DSR-RNA by Mmi1. Moreover, different from other YTH domain family proteins, Mmi1-YTH domain has a distinctive RNA-binding properties although it has a similar fold as other ones. [ABSTRACT FROM AUTHOR]

Sb-doped ZnO films were fabricated on c-plane sapphire using the pulsed laser deposition method and characterized by Hall effect measurement, X-ray photoelectron spectroscopy, X-ray diffraction, photoluminescence, and positron annihilation spectroscopy. Systematic studies on the growth conditions with different Sb composition, oxygen pressure, and post-growth annealing were conducted. If the Sb doping concentration is lower than the threshold ∼8 × 1020 cm−3, the as-grown films grown with an appropriate oxygen pressure could be n∼4 × 1020 cm−3. The shallow donor was attributed to the SbZn related defect. Annealing these samples led to the formation of the SbZn-2VZn shallow acceptor which subsequently compensated for the free carrier. For samples with Sb concentration exceeding the threshold, the yielded as-grown samples were highly resistive. X-ray diffraction results showed that the Sb dopant occupied the O site rather than the Zn site as the Sb doping exceeded the threshold, whereas the SbO related deep acceptor was responsible for the high resistivity of the samples. [ABSTRACT FROM AUTHOR]

In the progress of nonlinear optics, multiphoton absorption (MPA) upconversion lasing enables many vital applications in bioimaging, three-dimensional optical data storage, and photodynamic therapy. Here, efficient four-photon absorption upconversion lasing from the ZnO/ZnMgO multiple quantum wells (MQWs) at room temperature is realized. Moreover, the MPA upconversion lasing and third-harmonic generation peak generated in the MQWs under the excitation of a femtosecond (fs) laser pulse were observed concurrently, and the essential differences between each other were studied comprehensively. Compared with the ZnO film, the upconversion lasing peak of the ZnO/ZnMgO MQWs exhibits a clear blue shift. In addition, the four-photon absorption upconversion photoluminescence (PL) intensity was enhanced in the MQWs/Au nanoparticles (NPs) by the metal-localized surface plasmons (LSPs). The work paves the way for short-wavelength lasers by taking advantage of the high stability and large exciton binding energy of the MQWs' structures. [ABSTRACT FROM AUTHOR]

Two novel benzothiadiazole derivatives were prepared. Clear color changes from orange‐red to blue (DPCN) and pink to green (DPTPE) were observed after the addition of fluoride ions (F−). DPCN and DPTPE displayed ratiometric fluorescence changes in the presence of F−. 1H‐NMR titration and DFT calculations confirmed deprotonation in the presence of F−. Compared with DPTPE, the hydrogen proton of the imine group in DPCN had higher activity due to the influence of the strong electron‐withdrawing cyano group, such that it was more easily deprotonated and the detection limit for F− was much lower. This work provided guidance for the further design and preparation benzothiadiazole based colorimetric and ratiometric fluorescence sensor for F−. [ABSTRACT FROM AUTHOR]

Trace detection of nitroaromatic explosives in aqueous solution is important for environmental pollution evaluation and terrorist prevention. Here, a new pyrenyl‐based aggregation‐induced emission (AIE) fluorochrome (CPPyV) with desirable fluorescent performance was synthesized and applied to detect 2,4,6‐trinitrotoluene (TNT) in water. The fluorescence of CPPyV can be selectivity and efficiently quenched by TNT. The Stern‐Volmer constant (KSV) of CPPyV for TNT was determined to be 6.2×105 M−1, with a low detection limit of 4 nM. Notably, CPPyV could be used for TNT determinations in real water samples and also developed as a fluorescent paper sensor which could efficiently detect TNT by naked‐eye when the TNT concentration was 1.0×10−8 M. The quenching process was dynamic quenching mechanism and the theoretical calculations revealed that photoin‐duced electron transfer (PET) from excited CPPyV to electron deficient TNT was the main reason for fluorescence quenching. The excellent detection performance of CPPyV yielded it a promising sensor material for actual field applications. [ABSTRACT FROM AUTHOR]

An effect of rapid thermal annealing (RTA) on emission properties of InGaAsSb/AlGaAsSb multiple quantum wells (MQWs) grown by molecular‐beam epitaxy is systematically investigated by photoluminescence (PL) spectra. The emission from free‐exciton and localized carriers is confirmed in as‐grown InGaAsSb/AlGaAsSb MQWs using temperature and excitation power‐dependent PL spectra. The results of RTA for different times at a fixed temperature of 350 °C are analyzed. The PL intensity of InGaAsSb/AlGaAsSb MQWs is increased after an RTA process, and the peak position is slightly blueshifted at 300 K. Low‐temperature PL spectra show improved emission of free‐exciton and deteriorated localized carriers recombination at an annealing time of 60 s. Double crystal X‐ray diffraction (DCXRD) measurements are also carried out to study the crystalline quality before and after annealing. These results indicate that a suitable RTA treatment is effective in reducing the densities of nonradiative recombination centers, which implies an improved optical property and crystalline quality of quantum well structures. This study provides valuable understanding of recombination processes and improvement of optical properties by RTA treatment in InGaAsSb/AlGaAsSb MQWs. [ABSTRACT FROM AUTHOR]

MgtE is a Mg2+ channel conserved in organisms ranging from prokaryotes to eukaryotes, including humans, and plays an important role in Mg2+ homeostasis. The previously determined MgtE structures in the Mg2+-bound, closed-state, and structure-based functional analyses of MgtE revealed that the binding of Mg2+ ions to the MgtE cytoplasmic domain induces channel inactivation to maintain Mg2+ homeostasis. There are no structures of the transmembrane (TM) domain for MgtE in Mg2+-free conditions, and the pore-opening mechanism has thus remained unclear. Here, we determined the cryo-electron microscopy (cryo-EM) structure of the MgtE-Fab complex in the absence of Mg2+ ions. The Mg2+-free MgtE TM domain structure and its comparison with the Mg2+-bound, closed-state structure, together with functional analyses, showed the Mg2+-dependent pore opening of MgtE on the cytoplasmic side and revealed the kink motions of the TM2 and TM5 helices at the glycine residues, which are important for channel activity. Overall, our work provides structure-based mechanistic insights into the channel gating of MgtE. MgtE is a magnesium-selective ion channel whose gating is regulated by cytoplasmic magnesium concentration; this cryo-EM study reveals how MgtE undergoes magnesium-dependent structural changes to open the pore on the cytoplasmic side. [ABSTRACT FROM AUTHOR]

Robust polariton in the strong‐coupling regime plays a central role in understanding Bose–Einstein condensation (BEC), which is also an ideal platform for the simulation of bosonization processes and novel engineering polariton devices that are related to quantum phase transitions. A two‐dimensional ZnO nanoplate is firstly utilized to construct microcavity polaritons, and a robust polariton BEC laser is successfully realized at room temperature (RT). High stability of the exciton state and the enhanced coupling strength in the nanoplate cavity are effective for polaritons. The giant Rabi splitting of 120 meV is extracted from the RT dispersion pattern. The evolution of polariton BEC exhibits a typical blue‐shift, and its saturation behavior shows that the interaction strength of the polaritons is deduced from the energy renormalization. Remarkably, the value of the interaction strength is two orders of magnitude higher than reported values, which implies that many‐body correlation may be dominant in the polariton strongly interacting polariton systems. The results open up the prospect of realizing robust polariton BEC lasers at high temperature. [ABSTRACT FROM AUTHOR]

• A hybrid consisting of Zn 2 GeO 4 (ZGO) rods grown within CNT framework is synthesized. • The hybrid is grown by one-step hydrothermal method. • Crosslinked ZGO/CNTs-O hybrid has a large contact surface area and many active sites. • Flexible CNTs act as superior connective bridges and improve structural stability. • ZGO/CNTs-O hybrid shows potential for use as supercapacitor electrode material. Currently, there are three primary obstacles to the development of high-performance supercapacitors: low electron conductivity of the electrode materials used, their poor ion-transport efficiency, and the unstable structure. Herein, to overcome these obstacles, one-dimensional Zn 2 GeO 4 (ZGO) rods were grown within a carbon nanotube (CNT) framework using a simple one-step hydrothermal strategy for use as a supercapacitor electrode material. The crosslinked ZGO/CNT-O hybrid exhibits a large contact surface area with respect to electrolytes, contains abundant electrochemical active sites, and has short ion-diffusion paths. Further, the flexible CNTs act as superior connective bridges, promoting electron transmission and resulting in a stable structure. The ZGO/CNT-O hybrid showed a specific capacitance of 164.25 F/g at a current density of 1 A/g. It also displayed superior cycling durability, exhibiting a specific capacity of 120 F/g at a current density of 10 A/g, even after 200,000 cycles. A simple crosslinking strategy and prolonged cycle durability are demonstrated, which endow ZGO/CNT-O with potential for use in supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

Advances in polymeric matrices with ultralong and color-tunable phosphorescence were recently made, but their luminescence mechanism was not yet thoroughly understood. The current experimental and theoretical studies show that the red-shift of phosphorescence spectrum is caused by increasing the C–N and C=O of carbon dots in the polymeric matrix. In addition, theoretical calculations explain the charge transfer and spin orbit coupling of carbon dots in a system containing different covalent bonds. The phosphorescence emission color and lifetime can be modulated, which is applied into triple anti-counterfeiting of photo-stimulated-dependent color, time-dependent color, and time-dependent phosphorescence lifetime. In the application, the phosphorescence color of carbon dots in the polymeric matrix can be varied from deep blue (431 nm) to red (620 nm) with a maximal lifetime of 2.02 s and a maximum phosphorescence quantum yield of 20.1%. This work provides a new direction for the development of carbon dots with efficient and color-tunable ultra-long phosphorescence. [Display omitted] • The phosphorescence color of carbon dots can be varied from deep blue (431 nm) to red (620 nm) with a maximal lifetime of 2.02 s and a maximum phosphorescence quantum yield of 20.1%. • Theoretical calculations explain the charge transfer and spin orbit coupling of carbon dots in a system containing different covalent bonds. • The phosphorescence emission color and lifetime can be modulated, which is applied into triple anti-counterfeiting. [ABSTRACT FROM AUTHOR]

The 1D bundle-like NiCo 2 O 4 @TiO 2 hybrid was synthesized by a general and effective microemulsion strategy. It is found that after cycles the primitive 1D shape has been translated into broccoli-like fashion accompanied with abundant pores, enough active sites and convenient diffusion path, which endows the hybrid with high lithium storage capability and excellent cyclability. As anodes for LIBs, a reversible discharge capacity of 749.74 mA h g −1 is achieved after 800 long-term cycles at a current density of 2000 mA g −1 compared to 447.35 mAh g −1 of pure NiCo 2 O 4 . The hybrid also delivers superior rate performance such as 561.09 mAh g −1 even at a large current density of 5000 mA g −1 . Specifically, when the current density gradually returns to 2000 mA g −1 , the capacity still recovers to 696.69 mAh g −1 . [ABSTRACT FROM AUTHOR]

Because of the difficulties in populating and stabilizing the high energy triplet excited states, achieving violet organic afterglow at ambient conditions is still a formidable challenge. In this work, we propose an efficient strategy to activate violet and deep-blue afterglow of high energy triplet excited state by in situ embedding of carbon dots (CDs) into cyanuric acid crystals (CA) (named CDs@CA). The formation of covalent bonds in CDs@CA were found crucial in activating the afterglow with lifetime and phosphorescence quantum yields up to 1.80 s and 39%, respectively. Furthermore, the relationship between luminescence and copolymerization (covalent bonding) of CDs@CA were explored, which provides evidence for the regularity of multiple luminescent centers. A light-stimulated response of CDs@CA was found useful for applications in advanced anti-counterfeiting. These results provide a foundation for designing highly efficient violet and deep-blue organic afterglow materials with potential applications in the fields of bioimaging, anticounterfeiting, and optoelectronic devices. [Display omitted] • The formation of covalent bonds in CDs@CA were found crucial in activating the afterglow with lifetime and phosphorescence quantum yields up to 1.80 s and 39%, respectively. • The relationships between luminescence and copolymerization in CDs@CA were explored. • CDs-based materials can display various violet and deep-blue afterglow by further modifying and replacing the matrices with sub-fluorophores, such as P O, C O, B O, or C N. • The light-stimulated response of CDs@CA is proposed for applications in advanced anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Abstract: Using the first-principles method based on the density functional theory, we have studied magnetic and optical properties of V-doped GaN. For 12.5% V-doped GaN, total energy calculations show that the ferromagnetic state is 255meV lower than the antiferromagnetic state and is thus predicted to be the ground state with a Curie temperature above room temperature. The magnetic moments are localized at the V atoms and ferromagnetic exchange interaction is short ranged. The analysis of optical properties shows that V-doped GaN is a promising dielectric material and has potential applications in optoelectronic devices. [Copyright &y& Elsevier]

Single component white emitting materials are highly desired for lighting due to the negligible reabsorption, low energy transfer loss, and stable emission spectra. Carbon-based materials attracted much attention for their tunable luminescent properties and low toxicity nature. In this work, single-component white light emission solid-state carbon microspheres (CMSs) with photoluminescence quantum yield (PLQY) of 22.5% are synthesized by a simple one-step hydrothermal process. Beneficial from the large size of CMSs and Si and N related functional groups onto CMSs, the PL spectrum of the CMSs shows a broad and nearly Gaussian spectrum covering almost the entire visible spectrum. The cold white light-emitting diode (WLED), fabricated by putting the CMSs over a 365 nm ultraviolet (UV) LED chip, shows a color coordinate of (0.28, 0.34), correlated color temperature (CCT) of 8250 K and high color rendering index (CRI) of 82. Meanwhile, only little changes in CCT and CRI of the WLEDs were found at different operation voltages and times, attesting to the good color stability of the WLEDs based on single-component white phosphor of CMSs. These results reveal the potential of carbon-based white phosphor to be used in the field of white lighting. • Carbon microspheres were synthesized by using a facile one-step hydrothermal process. • Single-component white light emission was obtained from carbon microspheres. • White light-emitting diode with good color stability was achieved based on carbon microspheres. [ABSTRACT FROM AUTHOR]

The counter electrode (CE) plays an important role in determining the overall performance of quantum dots (QDs) sensitized solar cells (QDSCs) by collecting the electrons from the external circuit and catalyzing the reduction of oxidized electrolyte. Metal sulfides/selenides have been commonly used as CE in QDSCs. Among these CEs, the copper selenides are considered to be a superior CE for realizing highly efficient QDSCs due to its excellent catalytic activity. However, there has always been a trade-off between catalytic activity and conductivity in copper selenides CEs, such as the CE based on copper selenide nanoparticles has highest specific surface areas, leading to best catalytic activity compared with the CEs based on other copper selenide nanostructures (nanowires, nanorods, nanosheets etc.). But it also faces the worst conductivity due to a large number of grain boundaries existed in the copper selenide film based on nanoparticles. In this work, graphene (GR)/Cu 2-x Se composite material has been prepared via a facile hot injection method, and their photovoltaic and electrochemical properties are studied in detail. Through optimizing the ratio of GR: Cu 2-x Se and sintering temperature, the QDSCs based on the optimized GR/Cu 2-x Se composite CE shows an obvious improvement in cell performances and yield a PCE of 6.66% compared with that of the cells based on bare Cu 2-x Se (5.95%), bare Graphene (2.82%) and bare Cu x S (4.85%) CEs. The improved performance of the composite CE was attributed to the combining effect of high catalytic activity of Cu 2-x Se nanoparticles and good conductivity of graphene. This work demonstrates that GR/Cu 2-x Se composite CE could be potential candidate for realizing high efficiency QDSCs. • Graphene (GR)/Cu 2-x Se composite material has been prepared via a facile hot injection method. • The photovoltaic and electrochemical properties of the composite material were studied in detail. • The QDSSCs based on the composite CE shows an obvious improvement in cell performances and yield a PCE of 6.66%. [ABSTRACT FROM AUTHOR]

1D porous ZnCo 2 O 4 cuboids tailored by green natural soybean oil (SZCO) were harvested by a facile micro-emulsion strategy and were used as anodes for lithium ion batteries (LIBs). The as-prepared ZnCo 2 O 4 particles in a length range of 20–50 μm are characterized by 1D porous cuboid architecture and large specific surface area, exhibiting a high initial coulombic efficiency of 80.6%, good cycling durability and considerable specific capacity of 1029.3 mA h g−1 at 1000 mA g−1 even after 400 cycles. Furthermore, the electrode owns superior rate capability such as 1309.8, 1190.5, 954.9 and 724.4 mA h g−1 at current densities of 500, 1000, 2000, and 4000 mA g−1, respectively. The achieved electrochemical properties are ascribed to the favourable morphology, which increases the number of electrochemical active sites, contains effective diffusion channels, and inhibits drastic volume variations during repetitive Li-incorporation and removal. Image 1 • A simple micro-emulsion strategy tailored by soybean oil is proposed. • The initial columbic efficiency of SZCO reaches up to 84%. • A capacity of 1024 mA h g−1 is retained at a current density of 1000 mA g−1. • A rate capability of 724 mA h g−1 is achieved at a current density of 4000 mA g−1. [ABSTRACT FROM AUTHOR]

It is known that polychromatic carbon quantum dots (CQDs) can be obtained by doping and surface modification. The layer-wise synthesis of blue and green emitting CQDs (with typical sizes between 3 and 6 nm) is described here by adding oxalic acid and by introducing polycarboxy groups. By changing the external environment, the emission of CQDs can be adjusted in the blue-green spectral region (469–527 nm) under photoexcitation at 405 nm. The findings presented here provide new directions for the reversible regulatory transformation of polychromatic CQDs. The luminescence also is affected by a variety of conditions such as surface defects, degree of polymerization, polarity of external solutions, and hydrogen bonding which is studied in some detail. [ABSTRACT FROM AUTHOR]

Undoped and Ga-doped ZnO films were grown on c-sapphire using pulsed laser deposition (PLD) at the substrate temperature of 600 °C. Positron annihilation spectroscopy study (PAS) shows that the dominant VZn-related defect in the as-grown undoped ZnO grown with relative low oxygen pressure P(O2) is a vacancy cluster (most likely a VZn-nVO complex with n = 2, 3) rather than the isolated VZn which has a lower formation energy. Annealing these samples at 900 °C induces out-diffusion of Zn from the ZnO film into the sapphire creating the VZn at the film/sapphire interface, which favors the formation of vacancy cluster containing relatively more VZn. Increasing the P(O2) during growth also lead to the formation of the vacancy cluster with relatively more VZn. For Ga-doped ZnO films, the oxygen pressure during growth has significant influence on the electron concentration and the microstructure of the VZn-related defect. Green luminescence (GL) and yellow luminescence (YL) were identified in the cathodoluminescence study (CL) study, and both emission bands were quenched after hydrogen plasma treatment. The origin of the GL is discussed. [ABSTRACT FROM AUTHOR]