Epigenetic regulation of high light-induced anthocyanin biosynthesis by histone demethylase IBM1 in Arabidopsis.

In plant species, anthocyanin accumulation is specifically regulated by light signaling. Although the CONSTITUTIVELY PHOTOMORPHOGENIC1/SUPPRESSOR OF PHYA-105 (COP1/SPA) complex is known to control anthocyanin biosynthesis in response to light, the precise mechanism underlying this process remains largely unknown. Here, we report that Increase in BONSAI Methylation 1 (IBM1), a JmjC domain-containing histone demethylase, participates in the regulation of light-induced anthocyanin biosynthesis in Arabidopsis. The expression of IBM1 was induced by high light (HL) stress, and loss-of-function mutations in IBM1 led to accelerated anthocyanin accumulation under HL conditions. We further identified that IBM1 is directly associated with SPA1/3/4 chromatin in vivo to establish a hypomethylation status on H3K9 and DNA non-CG at these loci under HL, thereby releasing their expression. Genetic analysis showed that quadruple mutants of IBM1 and SPA1/3/4 resemble spa134 mutants. Overexpression of SPA1 in ibm1 mutants complements the mutant phenotype. Our results elucidate the significance and mechanism of IBM1 histone demethylase in the epigenetic regulation of anthocyanin biosynthesis in Arabidopsis under HL conditions.

Capillary-Bridge Controlled Patterning of BTR:PC71 BM Bulk Heterojunction Micro Arrays towards High-Performance Photodetector.

The patterning strategy of organic semiconductors is a crucial issue for integrated circuit. However, due to the uncontrollable liquid dewetting, most of the research is mainly focused on the patterning of single component, few works have been done on the patterning of multi-component or heterojunction, which play an important role in optoelectronic devices. Therefore, a capillary-bridge strategy was introduced for patterning of bulk heterojunction (BHJ) micro-arrays, with liquid crystalline BTR and PC71 BM utilized as donor and acceptor, respectively. The BTR:PC71 BM arrays presented hierarchical morphology with suitable phase separation, which contributes to the efficient charge generation and transport. Moreover, the photodetector exhibited excellent performance with the light on/off ratio greater than 2000, the responsivity of 40.57 A W-1 , and specific detectivity of 2.15×1012  Jones. Such progress demonstrates that the capillary-bridge strategy is a promising approach for the fabrication of high-quality BHJ micropatterns arrays.

Asymmetric Wettability Mediated Patterning of Single Crystalline Nematic Liquid Crystal and P-N Heterojunction Toward a Broadband Photodetector.

The well aligned and precise patterning of liquid crystals (LCs) are considered as two key challenges for large-scale and high-efficiency integrated optoelectronic devices. However, owing to the uncontrollable liquid flow and dewetting process in the conventional techniques, most of the reported research is mainly focused on simple sematic LCs, which are composed of terthiophenes or benzothieno[3, 2-b][1] benzothiophene backbone; only a few works are carried out on the complicated LCs. Herein, an efficient strategy was introduced to control the liquid flow and alignment of LCs and realized precise and high-quality patterning of A-π-D-π-A BTR, based on the asymmetric wettability interface. Through this strategy, the large-area and well-aligned BTR microwires array was fabricated, which exhibited highly ordered molecular packing and improved charge transport performance. Furthermore, the integration of BTR and PC71BM was achieved to manufacture uniform P-N heterojunction arrays, which still possessed highly ordered alignment of BTR. On the basis of these aligned heterojunction arrays, the high-performance photodetector exhibited an excellent responsivity of 27.56 A W-1 and a specific detectivity of 2.07 × 1012 Jones. This research not only provides an efficient strategy for the fabrication of aligned micropatterns of LCs but also gives a novel insight for the fabrication of high-quality micropatterns of the P-N heterojunction toward integrated optoelectronics.

All-Polymer Solar Cells with 17% Efficiency Enabled by the "End-Capped" Ternary Strategy.

Recently, all-polymer solar cells (all-PSCs) have received increasing attention and made tremendous progress. However, the power conversion efficiency (PCE) of all-PSCs still lags behind the polymer-donor-small-molecule-acceptor based organic solar cells, owing to the excessive phase separation with poor miscibility between polymer donor and acceptor. In this research, an "end-capped" ternary strategy is proposed by introducing PM6TPO as a third component to fabricate highly efficient all-PSCs. The PM6:PM6TPO:PY-IT based ternary devices exhibit impressive PCE of 17.0% with enhanced light absorption and optimal morphology, and the introduction of PM6TPO significantly reduces the phase separation. The ternary devices also exhibit improved stability, outstanding tolerance of active layer thickness, and high performance of 1 cm2 unit cells. More importantly, the "end-capped" ternary strategy enables efficient and facile improvement of all-PSCs performance without additional selection and complicated synthesis for the third component.

MicroRNA828 negatively regulates lignin biosynthesis in stem of Populus tomentosa through MYB targets.

Lignin biosynthesis in the sclerenchyma cells is strictly controlled by a complex network of genetic and environmental signals. In the last decades, the transcriptional regulation of lignin synthesis in woody species has been established. However, the role of microRNA-mediated post-transcriptional modulation in secondary cell wall biosynthesis remains poorly understood. Here, we identified a microRNA, miR828, involved in the regulation specific to lignin biosynthesis during stem development in Populus tomentosa Carr. miR828 is preferentially expressed in the secondary vascular tissues during stem development. Two MYB genes (MYB171 and MYB011) were validated as direct targets of miR828 by degradome analysis and green fluorescent protein signal detection. Overexpression of miR828 in poplar downregulated genes for lignin biosynthesis, resulting in reduced lignin content in cell walls. Conversely, suppression of miR828 in plants by the short tandem target mimics elevated the expression of lignin biosynthetic genes and increased lignin deposition. We further revealed that poplar MYB171, as the most abundant miR828 target in the stem, is a positive regulator for lignin biosynthesis. Transient expression assays showed that both MYB171 and MYB011 activated PAL1 and CCR2 transcription, whereas the introduction of miR828 significantly suppressed their expression that was induced by MYB171 or MYB011. Collectively, our results demonstrate that the miR828-MYBs module precisely regulates lignin biosynthesis during the stem development in P. tomentosa through transcriptional and post-transcriptional manners.

Conjugated Mesopolymer Achieving 15% Efficiency Single-Junction Organic Solar Cells.

The high-performance organic solar cells (OSCs) tend to choose the polymers with high molecular weight as donors, which easily produce good crystallinity to facilitate intermolecular charge transfer. However, these polymers usually accompanied by the low solubility and synthetic difficulty, increasing batch-to-batch variations. The proposal of conjugated mesopolymers (molar mass (Mn ) in 1-10 kDa) can overcome these problems. Herein, a new mesopolymer, MePBDFClH as donor material is designed and synthesized, and firstly applied in OSCs. As a comparison, other lower molecular weight mesopolymer of MePBDFClL and higher molecular weight polymer of PBDFCl with same structure are also prepared and investigated. Because of its appropriate phase separation and miscibility in the blend film, the MePBDFClH exhibits the highest power conversion efficiency (PCE) of 15.06% among the three materials. Meanwhile, the champion PCE is a new record for benzo[1,2-b:4,5-b']difuran-based photovoltaic materials. Importantly, comparing to the pronounced PCE decrease of polymer PBDFCl by about 12%, a slightly PCE difference for mespolymer MePBDFClL is only less than 5%, reducing the batch-to-batch variation. This work not only suggests that the benzo[1,2-b:4,5-b']difuran unit is a promising electron-donating core but also shows that the mesopolymers have great potentials to produce the low-differentiated and high-performance organic photovoltaic materials.

Meniscus-Assisted Coating with Optimized Active-Layer Morphology toward Highly Efficient All-Polymer Solar Cells.

Morphology control is the key to engineering highly efficient solution-processed solar cells. Focusing on the most promising application-oriented photovoltaic all-polymer solar cells (all-PSCs), herein a facile and effective meniscus-assisted-coating (MAC) strategy is reported for preparing high-quality blend films with enhanced crystallinity and an interpenetrating nanofiber network morphology. The all-PSCs based on MAC exhibit excellent optoelectronic properties with efficiencies exceeding 15%, which is the best performance of solution-printing-based all-PSCs, as well as better stability. The crystallization kinetics of the polymer blend film is investigated by in situ UV-vis absorption spectroscopy, and the result explains the linear relationship between the meniscus advance speed and the crystallinity (crystallization rate) of the polymer. To verify the compatibility and universality of this strategy, the MAC strategy is applied to the other three binary systems. By precisely controlling the meniscus advancing speed, 1 cm2 all-PSC devices whose efficiencies exceed 12% are fabricated. Such progress demonstrates that the application of the MAC strategy is a promising approach for the fabrication of high-efficiency all-PSCs.

Sociodemographic, occupational, and personal factors associated with sleep quality among Chinese medical staff: A web-based cross-sectional study.

Background: Sleep quality among medical staff affects not only their own health but also the health of their patients. This study aimed to investigate the sociodemographic, occupational, and personal factors associated with sleep quality among medical staff in mainland China. Methods: An online survey was conducted from January 10 to February 5, 2019, involving 3,684 medical staff (female: 84.9%; mean age: 31.6 ± 7.7; age range: 18-72). Sleep quality was measured by the Chinese version of the Pittsburgh Sleep Quality Index (C-PSQI). Sociodemographic, occupational characteristics, and personal lifestyle factors were measured by standard questions. Binary logistic regression analyses were used to determine the factors associated with sleep quality. Results: 57.9% (95% CI: 56.3-59.5%) of the study population experienced poor sleep quality (C-PSQI > 5). Binary logistic regression showed that poor sleep quality were associated with lower level of education, higher level of hospital care, longer weekly working hours, more than 30 min of cell phone use at bedtime, shift work (OR 1.33, 95% CI[1.12-1.58], P = 0.001), lack of regular naps (OR 1.46, 95% CI[1.26-1.69], P < 0.001) and lack of routine exercise (OR 1.69, 95% CI[1.46-1.97], P < 0.001). Conclusions: Poor sleep quality is highly prevalent among medical staff in mainland China. The findings indicate that appropriate strategies, such as implementing regular breaks, regulating overtime work and vacation interruptions, as well as developing exercise programs, relaxation training, and stress-management programs could help improve the sleep quality of medical staff.

Self-Harm History, Anxiety-Depression, Severity of Disease, and Insight Are Significantly Associated With Suicide Risk in Forensic Psychiatric Inpatients of China.

Background: Forensic psychiatric patients have higher suicide risk than the general population. This study aimed to evaluate the extent of suicide risk and to explore the associated factors in forensic psychiatric inpatients in China. Methods: We conducted a cross-sectional study from 1st November, 2018 to 30th January, 2019 in the Forensic Psychiatric Hospital of Hunan Province, China. Patient's information on socio-demographic, clinical, and criminological characteristics was collected. The suicidality subscale of the MINI-International Neuropsychiatric Interview (M.I.N.I.), the Brief Psychiatric Rating Scale (BPRS), and the Severity of Illness of Clinical Global Impressions Scale (CGI-SI) were used to measure present suicide risks, psychiatric symptoms, and the severity of the patient's disease, respectively. Binary logistic regression models were used to examine factors associated with suicide risk. Results: Twenty-one percent (84/408) of the forensic psychiatric inpatients reported suicide risk. Logistic regression analysis suggested that self-harm history (OR:3.47, 95% confidence interval CI: 1.45-8.33), symptoms of anxiety-depression (OR:1.15, 95% CI:1.04-1.27), and more severe mental disorder (OR:1.42, 95% CI:1.08-1.87) were associated with elevated suicide risk, while insight disorder (OR:0.81, 95% CI:0.65-0.99) was related to decreasing suicide risk. Conclusion: The study supplied useful clinical information to recognize high suicide risk in forensic psychiatric inpatients and may aid the development of valuable strategies for preventing and reducing suicide events.

Mental health service use and its associated factors among nurses in China: a cross-sectional survey.

BACKGROUND: To facilitate mental health service planning for nurses, data on the patterns of mental health service use (MHSU) among nurses are needed. However, MHSU among Chinese nurses has seldom been studied. Our study aimed to explore the rate of MHSU among Chinese nurses and to identify the factors associated with MHSU. METHODS: A self-designed anonymous questionnaire was used in this study. MHSU was assessed by the question, "Have you ever used any kind of mental health services, such as mental health outpatient services or psychotherapies, when you felt that your health was suffering due to stress, insomnia, or other reasons?" The answer to the question was binary (yes or no). Sleep quality, burnout, and depressive symptoms were assessed using the Chinese version of the Pittsburgh Sleep Quality Index , the Chinese version of the Maslach Burnout Inventory-General Survey and the two-item Patient Health Questionnaire, respectively. Chi-square tests and binary logistic regression were used for univariate and multivariate analyses. RESULTS: A total of 10.94% (301/2750) of the nurses reported MHSU. 10.25% (282/2750) of the nurses had poor sleep quality, burnout and depressive symptoms, and only 26.95% of these nurses reported MHSU. Very poor sleep quality (OR 9.36, 95% CI [5.38-16.29]), mid-level professional title (OR 1.48, 95% CI [1.13-1.93]) and depressive symptoms (OR 1.66, 95% CI [1.28-2.13]) were independent factors associated with MHSU. CONCLUSIONS: Most of the nurses have experienced burnout, poor sleep quality or depressive symptoms and the MHSU rate among them was low. Interventions to improve the mental health of nurses and to promote the use of mental health services are needed.

Workplace violence against hospital healthcare workers in China: a national WeChat-based survey.

BACKGROUND: Workplace violence (WPV) is a serious issue for healthcare workers and leads to many negative consequences. Several studies have reported on the prevalence of WPV in China, which ranges from 42.2 to 83.3%. However, little information is available regarding the correlates of WPV among healthcare workers and the differences across the different levels of hospitals in China. This study aimed to explore the correlates of WPV and career satisfaction among healthcare workers in China. METHODS: A self-designed WeChat-based questionnaire was used that included demographic and occupational factors. The Chinese version of the Workplace Violence Scale was used to measure WPV. Career satisfaction was assessed using two questions about career choices. Descriptive analyses, chi-square tests and multivariate logistic regressions were used. RESULTS: A total of 3706 participants (2750 nurses and 956 doctors) responded to the survey. Among the 3684 valid questionnaires, 2078 (56.4%) reported at least one type of WPV in the last year. Multivariate logistic regressions revealed that male sex, shift work, bachelor's degree education, a senior professional title, working more than 50 h per week and working in secondary-level hospitals were risk factors associated with WPV. Healthcare workers who had experienced higher levels of WPV were less likely to be satisfied with their careers. CONCLUSIONS: WPV remains a special concern for the Chinese healthcare system. Interventions to reduce WPV should be implemented by health authorities to create a zero-violence practice environment.

Spatial Coherence of Spin-Orbit-Coupled Bose Gases.

Spin-orbit-coupled Bose-Einstein condensates (SOBECs) exhibit two new phases of matter, now known as the stripe and plane-wave phases. When two interacting spin components of a SOBEC spatially overlap, density modulations with periodicity given by the spin-orbit coupling strength appear. In equilibrium, these components fully overlap in the miscible stripe phase and overlap only in a domain wall in the immiscible plane-wave phase. Here we probe the density modulation present in any overlapping region with optical Bragg scattering and observe the sudden drop of Bragg scattering as the overlapping region shrinks. Using an atomic analog of the Talbot effect, we demonstrate the existence of long-range coherence between the different spin components in the stripe phase and surprisingly even in the phase-separated plane-wave phase.

Two-Dimensional High-Quality Monolayered Triangular WS2 Flakes for Field-Effect Transistors.

Large-area uniform of single-crystal tungsten disulfide (WS2) is important for advanced optoelectronics based on two-dimensional (2D) atomic crystals. However, difficulties in controlling the interrelated growth parameters restrict its development in devices. Herein, we present the synthesis of triangular monolayered WS2 flakes with good uniformity and single crystal by adjusting the introduction time of sulfur precursor and the distances between the sources and substrates to control the nucleation density. Investigation of the morphology and structure by transmission electron microscopy and Raman spectroscopy indicates that a series of triangular (side length of 233 µm) monolayered WS2 flakes shows high-quality structure and homogenous crystallinity. Field-effect transistors based on the fabricated triangular monolayered WS2 with single crystal demonstrate environmentally stable charge transport with a field-effect mobility of 50.5 cm2/V s and current modulation Ion/ Ioff of ∼107. The results of this study pave the way for the application of monolayered WS2 in a multitude of 2D-material-based devices.

Second Chern number of a quantum-simulated non-Abelian Yang monopole.

Topological order is often quantified in terms of Chern numbers, each of which classifies a topological singularity. Here, inspired by concepts from high-energy physics, we use quantum simulation based on the spin degrees of freedom of atomic Bose-Einstein condensates to characterize a singularity present in five-dimensional non-Abelian gauge theories-a Yang monopole. We quantify the monopole in terms of Chern numbers measured on enclosing manifolds: Whereas the well-known first Chern number vanishes, the second Chern number does not. By displacing the manifold, we induce and observe a topological transition, where the topology of the manifold changes to a trivial state.

Sonication-assisted liquid-phase exfoliated α-GeTe: a two-dimensional material with high Fe3+ sensitivity.

We describe sonication-assisted liquid-phase exfoliation of rhombohedral germanium telluride (α-GeTe) to obtain a good dispersion of α-GeTe nanosheets in ethanol. The thickness of the α-GeTe nanosheets is dependent on the exfoliation conditions, and few-layer α-GeTe nanosheets of 2-4 layers and even monolayer α-GeTe were obtained. We use first-principles calculations to investigate the structural, electronic, and optical properties of monolayer and bulk α-GeTe and compare the optical band gap of centrifugally fractionated α-GeTe nanosheet dispersions with the computational predictions. We demonstrate that few layer α-GeTe nanosheets are purified selectively through centrifugation, and they exhibit high sensitivity to Fe3+. The scalable production of two-dimensional α-GeTe nanosheets can be used in the future optoelectronic industry.

Contact Engineering of Molybdenum Ditelluride Field Effect Transistors through Rapid Thermal Annealing.

Understanding and engineering the interface between metal and two-dimensional materials are of great importance to the research and development of nanoelectronics. In many cases the interface of metal and 2D materials can dominate the transport behavior of the devices. In this study, we focus on the metal contacts of MoTe2 (molybdenum ditelluride) FETs (field effect transistors) and demonstrate how to use post-annealing treatment to modulate their transport behaviors in a controlled manner. We have also carried out low temperature and transmission electron microscopy studies to understand the mechanisms behind the prominent effect of the annealing process. Changes in transport properties are presumably due to anti-site defects formed at the metal-MoTe2 interface under elevated temperature. The study provides more insights into MoTe2 field effect devices and suggests guidelines for future optimizations.

Large-Scale Synthesis of a Uniform Film of Bilayer MoS2 on Graphene for 2D Heterostructure Phototransistors.

The large-scale synthesis of atomically thin, layered MoS2/graphene heterostructures is of great interest in optoelectronic devices because of their unique properties. Herein, we present a scalable synthesis method to prepare centimeter-scale, continuous, and uniform films of bilayer MoS2 using low-pressure chemical vapor deposition. This growth process was utilized to assemble a heterostructure by growing large-scale uniform films of bilayer MoS2 on graphene (G-MoS2/graphene). Atomic force microscopy, Raman spectra, and transmission electron microscopy characterization demonstrated that the large-scale bilayer MoS2 film on graphene exhibited good thickness uniformity and a polycrystalline nature. A centimeter-scale phototransistor prepared using the G-MoS2/graphene heterostructure exhibited a high responsivity of 32 mA/W with good cycling stability; this value is 1 order of magnitude higher than that of transferred MoS2 on graphene (2.5 mA/W). This feature results from efficient charge transfer at the interface enabled by intimate contact between the grown bilayer MoS2 (G-MoS2) and graphene. The ability to integrate multilayer materials into atomically thin heterostructures paves the way for fabricating multifunctional devices by controlling their layer structure.