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In most legumes, two typical features found in leaves are diverse compound forms and the pulvinus-driven nyctinastic movement. Many genes have been identified for leaf-shape determination, but the underlying nature of leaf movement as well as its association with the compound form remains largely unknown. Using forward-genetic screening and whole-genome resequencing, we found that two allelic mutants of Medicago truncatula with unclosed leaflets at night were impaired in MtDWFARF4A (MtDWF4A), a gene encoding a cytochrome P450 protein orthologous to Arabidopsis DWARF4. The mtdwf4a mutant also had a mild brassinosteroid (BR)-deficient phenotype bearing pulvini without significant deficiency in organ identity. Both mtdwf4a and dwf4 could be fully rescued by MtDWF4A, and mtdwf4a could close their leaflets at night after the application of exogenous 24-epi-BL. Surgical experiments and genetic analysis of double mutants revealed that the failure to exhibit leaf movement in mtdwf4a is a consequence of the physical obstruction of the overlapping leaflet laminae, suggesting a proper geometry of leaflets is important for their movement in M. truncatula. These observations provide a novel insight into the nyctinastic movement of compound leaves, shedding light on the importance of open space for organ movements in plants.

The LAM1 transcription factor regulates expansion of primary leaflets in the compound leaves of tomato, and also affects floral organ development, fruit size, and initiation of secondary leaflets., Plant-specific WOX family transcription factors play important roles ranging from embryogenesis to lateral organ development. The WOX1 transcription factors, which belong to the modern clade of the WOX family, are known to regulate outgrowth of the leaf blade specifically in the mediolateral axis; however, the role of WOX1 in compound leaf development remains unknown. Phylogenetic analysis of the whole WOX family in tomato (Solanum lycopersicum) indicates that there are 10 members that represent the modern, intermediate, and ancient clades. Using phylogenetic analysis and a reverse genetic approach, in this study we identified SlLAM1 in the modern clade and examined its function and tissue-specific expression pattern. We found that knocking out SlLAM1 via CRISPR/Cas9-mediated genome editing led to narrow leaves and a reduced number of secondary leaflets. Overexpression of tomato SlLAM1 could rescue the defects of the tobacco lam1 mutant. Anatomical and transcriptomic analyses demonstrated that floral organ development, fruit size, secondary leaflet initiation, and leaf complexity were altered due to loss-of-function of SlLAM1. These findings demonstrate that tomato SlLAM1 plays an important role in the regulation of secondary leaflet initiation, in addition to its conserved function in blade expansion.

Optimizing plant architecture is an efficient approach for breeders to increase crop yields, and phytohormones such as gibberellins (GAs) play an important role in controlling growth. Medicago truncatula is a model legume species, but the molecular mechanisms underlying its architecture are largely unknown. In this study, we examined a tobacco retrotransposon Tnt1-tagged mutant collection of M. truncatula and identified dwarf and increased branching 1 (dib1), which exhibited extreme dwarfism and increased numbers of lateral branches. By analysis of the flanking sequences of Tnt1 insertions in different alleles of the tagged lines, we were able to clone DIB1. Linkage analysis and reverse screening of the flanking-sequence tags identified Medtr2g102570 as the gene corresponding to the DIB1 locus in the dib1 loss-of-function mutants. Phylogenetic analysis indicated that DIB1 was the ortholog of PsGA3ox1/Le in Pisum sativum. Expression analysis using a GUS-staining reporter line showed that DIB1 was expressed in the root apex, pods, and immature seeds. Endogenous GA4 concentrations were markedly decreased whilst some of representative GA biosynthetic enzymes were up-regulated in the dib1 mutant. In addition, exogenous application of GA3 rescued the dib1 mutant phenotypes. Overall, our results suggest that DIB1 controls plant height and axillary bud outgrowth via an influence on the biosynthesis of bioactive GAs. DIB1 could therefore be a good candidate gene for breeders to optimize plant architecture for crop improvement.

Nyctinastic leaf movement of Fabaceae is driven by the tiny motor organ pulvinus located at the base of the leaf or leaflet. Despite the increased understanding of the essential role of ELONGATED PETIOLULE1 (ELP1)/PETIOLE LIKE PULVINUS (PLP) orthologs in determining pulvinus identity in legumes, key regulatory components and molecular mechanisms underlying this movement remain largely unclear. Here, we used WT pulvinus and the equivalent tissue in the elp1 mutant to carry out transcriptome and proteome experiments. The omics data indicated that there are multiple cell biological processes altered at the gene expression and protein abundance level during the pulvinus development. In addition, comparative analysis of different leaf tissues provided clues to illuminate the possible common primordium between pulvinus and petiole, as well as the function of ELP1. Furthermore, the auxin pathway, cell wall composition and chloroplast distribution were altered in elp1 mutants, verifying their important roles in pulvinus development. This study provides a comprehensive insight into the motor organ of the model legume Medicago truncatula and further supplies a rich dataset to facilitate the identification of novel players involved in nyctinastic movement.

BackgroundDespite efforts to promote professionalism among physicians, many studies have confirmed the ongoing prevalence of unprofessional behaviours in medicine and alluded to the challenges to professionalism that physicians may encounter. Physicians may regularly witness unprofessional events and may even participate in unprofessional practices. Therefore, the current study aims to identify common challenges to professionalism and physicians’ priorities when coping with such challenges，in hopes of shedding light on the East Asian environment with respect to physician professionalism. MethodsFive focus groups were conducted with a total of 49 clinical physicians from two tertiary hospitals in Shenyang, the largest city in northern China. Socio-demographic data were obtained through a brief questionnaire, and participants were de-identified after being linked to verbal data from the focus groups. Focus group interviews were audio-recorded and later transcribed and subjected to an inductive thematic analysis.ResultsA content analysis of the focus groups demonstrated that common professionalism challenges could be classified into five categories, namely: patients and their families (38%), society (22%), peers or teams (21%), institutions (13%), and education (n = 6%). Physicians failed to find current remediation measures, such as, discussing with supervisors, or reporting challenges to hospital or health authorities very effective.ConclusionsThe current study suggests that challenges from patients and their families contributed the most to professionalism challenges in the hospitals in northern China. In terms of the systematic reform of medical education and the healthcare delivery system, health authorities and hospital administrators should aim at addressing challenges to physician professionalism by building up a protective atmosphere.

Exploring advanced electrocatalysts for the sluggish oxygen reduction reaction is extremely important for fuel cell commercialization but still remains a great challenge, especially the durability issue that gains increasing attention. Herein, we demonstrate an extremely durable catalyst prototype that combines structurally ordered intermetallic nanoparticles (NPs) with mesoporous carbon. With ZIF-8 derived mesoporous carbon supported Pt3Co intermetallic NPs (Pt3Co/DMC-F) as an example, we illustrate its synthetic details, electrocatalytic performance and durability enhancement mechanism. The Pt3Co/DMC-F catalyst exhibited significant enhancement in activity and durability. More importantly, its extraordinary performance was observed/verified in a H2/air PEM single cell test. The confinement of mesoporous carbon not only efficiently controls the particle size of Pt3Co and hampers their aggregation during thermal annealing and electrochemical reactions, but also significantly suppresses detachment. Beyond offering an advanced electrocatalyst, this study provides a solution to the durability issue of cathodes that has prevented practical application of proton exchange membrane fuel cells.

Highlights All the important single-atom catalysts (SACs) synthetic strategies, such as wet-chemistry method, atomic layer deposition, metal–organic framework-derived method, electrodeposition, high-temperature atom trapping from bulk particles, and vacancies/defects immobilized strategy, have been summarized and discussed in detail.Various metal-based (especially Pt, Pd, Ru, Fe, Co, Ni, Mo, W, V) SACs in electrocatalytic hydrogen evolution reaction (HER) have been systematically reviewed.The current key challenges in SACs for electrochemical HER are pointed out, and some potential strategies/perspectives are proposed., Hydrogen, a renewable and outstanding energy carrier with zero carbon dioxide emission, is regarded as the best alternative to fossil fuels. The most preferred route to large-scale production of hydrogen is by water electrolysis from the intermittent sources (e.g., wind, solar, hydro, and tidal energy). However, the efficiency of water electrolysis is very much dependent on the activity of electrocatalysts. Thus, designing high-effective, stable, and cheap materials for hydrogen evolution reaction (HER) could have a substantial impact on renewable energy technologies. Recently, single-atom catalysts (SACs) have emerged as a new frontier in catalysis science, because SACs have maximum atom-utilization efficiency and excellent catalytic reaction activity. Various synthesis methods and analytical techniques have been adopted to prepare and characterize these SACs. In this review, we discuss recent progress on SACs synthesis, characterization methods, and their catalytic applications. Particularly, we highlight their unique electrochemical characteristics toward HER. Finally, the current key challenges in SACs for HER are pointed out and some potential directions are proposed as well.

In this work, a glucose-derived carbon supported CrN composite is prepared by using a hydrothermal method and followed by a nitridating process. It is found that CrN nanoparticles in the composite are well-dispersed and separated by the carbon support. More importantly, the composite exhibits significantly enhanced oxygen reduction reaction activity than free-standing aggregated CrN nanoparticles, especially in acidic medium. The onset potential of the composite reaches 0.81 V in acidic medium, which is one of the highest values among the reported metal nitrides. The rotating ring disk electrode results indicate that the composite is more beneficial to O2 dissociation than free-standing CrN nanoparticles. Results of X-ray photoelectron spectroscopy, O2 temperature-programmed desorption and electrochemical impedance spectroscopy indicate that the significantly enhanced oxygen reduction reaction activity of the composite over free-standing CrN is derived not from the new formed active sites or enhanced oxygen adsorption but from the much enhanced electron transfer rate. This observation helps to understand the role of electron transfer rate playing in the oxygen reduction reaction activity of metal nitrides.

Plant height is a vital agronomic trait that greatly determines crop yields because of the close relationship between plant height and lodging resistance. Legumes play a unique role in the worldwide agriculture, however, little attention has been given to the molecular basis of their height. Here, we characterized the first dwarf mutant mini plant 1 (mnp1) of the model legume plant Medicago truncatula. Our study found that both cell length and the cell number of internodes were reduced in a mnp1 mutant. Using the forward genetic screening and subsequent whole-genome resequencing approach, we cloned the MNP1 gene and found that it encodes a putative copalyl diphosphate synthase (CPS) implicated in the first step of gibberellin (GA) biosynthesis. MNP1 was highly homologous to Pisum sativum LS. The subcellular localization showed that MNP1 was located in the chloroplast. Further analysis indicated that GA3 could significantly restore the plant height of mnp1-1, and expression of MNP1 in a cps1 mutant of Arabidopsis partially rescued its mini-plant phenotype, indicating the conservation function of MNP1 in GA biosynthesis. Our results provide valuable information for understanding the genetic regulation of plant height in M. truncatula.

Highly active catalyst for the hydrogen oxidation/evolution reactions (HOR and HER) plays an essential role for the water-to-hydrogen reversible conversion. Currently, increasing attention has been concentrated on developing low-cost, high-activity, and long-life catalytic materials, especially for acid media due to the promise of proton exchange membrane (PEM)-based electrolyzers and polymer electrolyte fuel cells. Although non-precious-metal phosphide (NPMP) catalysts have been widely researched, their electrocatalytic activity toward HER is still not satisfactory compared to that of Pt catalysts. Herein, a series of precious-metal phosphides (PMPs) supported on graphene (rGO), including IrP2-rGO, Rh2P-rGO, RuP-rGO, and Pd3P-rGO, are prepared by a simple, facile, eco-friendly, and scalable approach. As an example, the resultant IrP2-rGO displays better HER electrocatalytic performance and longer durability than the benchmark materials of commercial Pt/C under acidic, neutral, and basic electrolytes. To attain a current density of 10 mA cm-2, IrP2-rGO shows overpotentials of 8, 51, and 13 mV in 0.5 M dilute sulfuric acid, 1.0 M phosphate-buffered saline (PBS), and 1.0 M potassium hydroxide solutions, respectively. Additionally, IrP2-rGO also exhibits exceptional HOR performance in the 0.1 M HClO4 medium. Therefore, this work offers a vital addition to the development of a number of PMPs with excellent activity toward HOR and HER.

Preparing Pt–based one-dimensional (1D) ultrafine nanowires with abundant structural defects/grain boundaries and exploring their novel applications have attracted great interest in real-world applications. Here we introduce an environmentally friendly, facile aqueous solution approach to directly prepare a series of sub-3.0 nm PtRu ultrafine wavy nanowires. Characterizations show that the PtRu nanowires are alloy polycrystalline structures with abundant structural defects/grain boundaries. We first introduce the as-synthesized PtRu nanowires into electrochemical biosensors for the detection of DA and find that the Pt7Ru3 nanowires exhibit excellent electrocatalytic activity to DA with fast response, ultralow limit of detection, and excellent selectivity at a potential of 0.3 V in 0.1 M phosphate buffered solution (pH 7.2). This study shows an effective approach to the development of ultrafine PtRu nanowires as electrocatalysts for electrochemical nonenzymatic dopamine biosensors.

Background: Medical residents usually suffer from work overload and experience both personal and professional distress, which affects their level of the empathy to patients. Psychological capital (PsyCap) is a psychological resource that is negatively associated with indicators of distress. Objective: This study explored the potential mediating effect of PsyCap on the relationship between distress and empathy, which may help healthcare professionals in their defense of empathy erosion due to distress. Design: A total of 620 first-year residents were recruited for this cross-sectional survey. Empathy and PsyCap of residents were assessed by the Chinese version of the Jefferson Scale of Physician Empathy and the Psychological Capital Questionnaire, respectively. In this study, both personal and professional aspects contributing to resident distress were investigated by the Satisfaction with Life Scale and an occupational distress scale. T-tests and one-way ANOVA were used to test differences in empathy of residents. Pearson’s correlation was used to examine correlations between distress, PsyCap, and empathy. Structured equation modeling was used to conduct the pathway analysis to test the mediating effect of PsyCap on the association between distress and empathy. Results: 537 residents (86.6%) completed the survey. Distress, empathy, and PsyCap were significantly correlated (P

Recently, the synthesis of ultrathin nanostructures has attracted increasing interest because of their unique structure and properties. In this work, we report the synthesis of sub-2.0-nm Ru and composition-tunable RuPt nanowire networks using an environmentally friendly aqueous method. The structures were characterized using transmission electron microscopy (TEM), high-resolution TEM, X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) spectroscopy. Moreover, the combined utilization of sodium n-dodecyl sulfate and potassium fluoride was determined to play a key role in the formation of these ultrathin nanostructures. The electrocatalytic properties of the sub-2.0-nm RuPt nanowire networks were investigated for methanol oxidation in an acidic medium. The nanostructures displayed composition-dependent properties, and compared with commercial Ru50Pt50/C, the as-synthesized Ru56Pt44 ultrathin nanowire network exhibited enhanced stability.

Application of smart grid produces massive data. Unfortunately, the traditional analysis of power systems can not process such a huge volume of data in an efficient manner. Distributed computing like Map-Reduce framework in cloud environment can provide a promising solution to this problem by processing the data in parallel on a large amount of computing nodes. In this paper, we parallelize power flow calculation based on Map-Reduce programming framework and evaluate the efficiency. The classic Newton-Raphson method commonly used in power flow calculation is totally parallelized. To solve sparse linear equations in Map-Reduce framework, the factorization tree is carefully partitioned and in turn, all the variables in subtrees which are independent with each other can be calculated in parallel. Moreover, to map the proposed algorithm into Map-Reduce jobs, we also define the appropriate formats for the input, intermediate and output data. Experimental results demonstrate that the effectiveness of the proposed scheme.

The main challenges to the direct methanol fuel cells are the activity and durability of electrocatalysts. To alleviate such issues, a recently proposed strategy introduces an exotic element to form Pt-based alloy nanostructures. This study reports a green route to prepare porous flowerlike Pt72Ru28 nanoalloys assembled with sub-4.0 nm particles. The peak current density and mass activity on these as-synthesized porous flowerlike Pt72Ru28 nanoalloys can be increased to 10.98 mA cm−2 and 1.70 A mg−1 Pt for methanol oxidation in acidic medium. They are respectively 4.19/3.54, 4.27/5.0, and 5.74/1.73 times those on the commercial Pt black, Pt50Ru50 black, and Ru50Pt50/C. These porous flowerlike Pt72Ru28 nanoalloys have a much higher long-term durability than commercial Pt black, Pt50Ru50 black, and Ru50Pt50/C. More significantly, the porous Pt72Ru28 bimetallic nanoalloys have long-term solvent durability after immersion in water for 16 months. The peak current density and mass activity on porous Pt72Ru28 nanoalloys are still 7.76 mA cm−2 and 1.2 A mg−1 Pt. These experimental results show an effective approach to the development of PtRu nanoalloys as electrocatalysts with substantially enhanced activity and durability for direct methanol fuel cells.