Morphology and reactivity of size-selected titanium oxide nanoclusters on Au(111).

The morphology and reactivity of mass-selected titania clusters, Ti3O6 and Ti3O5, deposited onto Au(111) were studied by scanning tunneling microscopy and temperature programmed desorption. Despite differing by only one oxygen atom, the stoichiometric Ti3O6 and the sub-stoichiometric ("reduced") Ti3O5 clusters exhibit very different structures and preferred binding sites. The Ti3O6 clusters bind at step edges and form small assemblies (2-4 clusters) on Au terraces, while the "reduced" Ti3O5 clusters form much larger fractal-like assemblies that can extend across step boundaries. Annealing the Ti3O5,6/Au(111) systems to higher temperatures causes changes in the size-distributions of cluster assemblies, but does not lead to the formation of TiOx nanoislands for temperatures ≤700 K. Reactivity studies show that the reduced Ti3O5 cluster has higher activity than Ti3O6 for 2-propanol dehydration, although both clusters exhibit substantial activity for dehydrogenation to acetone. Calculations using DFT+U suggest that the differences in aggregate morphology and reactivity are associated with the number of undercoordinated Ti3c sites in the supported clusters

Communication-Efficient Cluster Federated Learning in Large-scale Peer-to-Peer Networks

A traditional federated learning (FL) allows clients to collaboratively train a global model under the coordination of a central server, which sparks great interests in exploiting the private data distributed on clients. However, once the central server suffers from a single point of failure, it will lead to system crash. In addition, FL usually involves a large number of clients, which requires expensive communication costs. These challenges inspire a communication-efficient design of decentralized FL. In this paper, we propose an efficient and privacy-preserving global model training protocol in the context of FL in large-scale peer-to-peer networks, CFL. The proposed CFL protocol aggregates local contributions hierarchically by a cluster-based aggregation mode, as well as a leverged authenticated encryption scheme to ensure the security communication, whose key is distributed by a modified secure communication key establishment protocol. Theoretical analyses show that CFL guarantees the privacy of local model update parameters, as well as integrity and authenticity under the widespread internal semi-honest and external malicious threat models. In particular, the proposed key revocation based on public voting can effectively defense against external adversaries hijacking honest participants to ensure the confidentiality of the communication keys. Moreover, the modified secure communication key establishment protocol indeed achieves high network connectivity probability to ensure transmission security of the system

Petrogenesis of arc-related peridotite hosted chromitite deposits in Sikhoran-Soghan mantle section, South Iran: evidence for proto-forearc spreading to boninitic stages

The Soghan-Sikhoran ophiolite in southeast Iran (Outer Zagros Ophiolite Belt) is a remnant of a series of Upper Triassic–Cretaceous supra-subduction zone (SSZ) ophiolites that formed along the Zagros suture zone, which is considered as the southern border of the Neo-Tethyan sea. These SSZ ophiolites are older than the Late Cretaceous Zagros ophiolites. The main part of the Soghan-Sikhoran ophiolite comprises layered ultramafic cumulates including dunites, wehrlites, and pyroxenites, and a tectonized mantle section including residual lherzolites, and depleted harzburgites with foliated/discordant dunite lenses. Podiform chromitites are common and are typically surrounded by thin dunitic haloes. Spinels in lherzolite–harzburgite are geochemically characterized by a low Cr# (42.0 to 52.6), and plot in an abyssal peridotite field on geochemical discrimination diagrams, whereas spinel in dunites and high-Cr chromitite spinels (Cr# = 52.4 to 76.4) show geochemical affinities to boninites. Lherzolites and harzburgites have low REE contents and experienced >17 vol% partial melting. The Soghan-Sikhoran ophiolite contains both high Cr# and low Cr# podiform chromitite types. Trace and REE element patterns of Soghan-Sikhoran rocks are similar to those in SSZ peridotites. The studied ophiolites show relatively moderate to high oxygen fugacities (ƒO2), with log units ranging from −0.4 to +0.4 for harzburgites, +0.2 for lherzolites, from − 0.7 to + 2.5 for pyroxenites, from +0.8 to +2.2 for dunites, and from + 0.6 to + 0.8 for chromitites. The moderate to high oxidation state of the studied upper-mantle ophiolitic complexes also suggests a boninitic source in the mantle wedge of the arc setting. The two-pyroxene thermometer yields mean equilibrium temperatures of 879 °C, 895 °C, 912 °C and 912 °C for harzburgites, lherzolites, dunites and pyroxenites, respectively. We therefore interpret that the spinels in the lherzolite-harzburgite crystallized from tholeiitic melt generated due to proto-forearc spreading and formation of the infant arc, whereas high-Cr# spinel in dunites and high-Cr# chromitite crystallized from boninitic melts during the mature arc stage, with an increasing contribution of slab-derived fluids at high ƒO2

Topologically Variable and Volumetric Morphing of 3D Architected Materials with Shape Locking

The morphing of 3D structures is suitable for i) future tunable material design for customizing material properties and ii) advanced manufacturing tools for fabricating 3D structures on a 2D plane. However, there is no inverse design method for topologically variable and volumetric morphing or morphing with shape locking, which limits practical engineering applications. In this study, we construct a general inverse design method for 3D architected materials for topologically variable and volumetric morphing, whose shapes are lockable in the morphed states, which can contribute to future tunable materials, design, and advanced manufacturing. Volumetric mapping of bistable unit cells onto any 3D morphing target geometry with kinematic and kinetic modifications can produce flat-foldable and volumetric morphing structures with shape-locking. This study presents a generalized inverse design method for 3D metamaterial morphing that can be used for structural applications with shape locking. Topologically variable morphing enables the manufacture of volumetric structures on a 2D plane, saving tremendous energy and materials compared with conventional 3D printing. Volumetric morphing can significantly expand the design space with tunable physical properties without limiting the selection of base materials

Authentic Leadership and Proactive Behavior: The Role of Psychological Capital and Compassion at Work

This study, which is based on survey data provided by 445 employees from a Chinese enterprise, examines the impact of authentic leadership on the proactive behavior of subordinates, in particular the mediating effect of subordinate psychological capital and the moderating effect of compassion at work. The results of our structural equation model reveal that: (1) There is a significant positive correlation between authentic leadership and the proactive behavior of subordinates; (2) psychological capital plays a full mediating role between authentic leadership and subordinate proactive behavior; (3) Compassion at work has a moderating effect on the positive relationship between authentic leadership and subordinate psychological capital and proactive behavior

Authentic Leadership and Proactive Behavior: The Role of Psychological Capital and Compassion at Work

This study, which is based on survey data provided by 445 employees from a Chinese enterprise, examines the impact of authentic leadership on the proactive behavior of subordinates, in particular the mediating effect of subordinate psychological capital and the moderating effect of compassion at work. The results of our structural equation model reveal that: (1) There is a significant positive correlation between authentic leadership and the proactive behavior of subordinates; (2) psychological capital plays a full mediating role between authentic leadership and subordinate proactive behavior; (3) Compassion at work has a moderating effect on the positive relationship between authentic leadership and subordinate psychological capital and proactive behavior

Risk Factors for Mortality Among Critical Acute Pancreatitis Patients with Carbapenem-Resistant Organism Infections and Drug Resistance of Causative Pathogens

IntroductionCarbapenem-resistant organisms (CRO) have emerged as a major global public health threat, but their role in critical acute pancreatitis (CAP) is still not defined. Our study aims to investigate risk factors associated with mortality and drug resistance among CAP patients with CRO infection.MethodsThe clinical characteristics of CAP patients with CRO infection and drug resistance of causative pathogens from January 1, 2016, to October 1, 2021, were reviewed retrospectively. Independent risk factors for mortality were determined via univariate and multivariate analyses.ResultEighty-two CAP patients suffered from CRO infection, with mortality of 60.0%. The independent risk factors for mortality were procalcitonin > 5 ng/L (hazard ratio = 2.300, 95% confidence interval = 1.180-4.484, P = 0.014) and lactic acid > 2 mmol/L (hazard ratio = 2.101, 95% confidence interval = 1.151-3.836, P = 0.016). The pancreas was the main site of infection, followed by lung, bloodstream and urinary tract. Klebsiella pneumoniae and Acinetobacter baumannii were the main pathogenic bacteria of CRO strains with extensive antibiotic resistance (> 60%) to 6 of 8 common antibiotics, except sulfamethoxazole (56.3%) and tigecycline (33.2%).ConclusionCRO infection has become a serious threat for CAP patients, with high rates of mortality. Procalcitonin and lactic acid represent two independent risk factors for mortality in CAP patients with CRO infection. Klebsiella pneumoniae and Acinetobacter baumannii are the primary categories of CRO pathogens. Greater efforts are needed for early prevention and prompt treatment of CRO infections in CAP patients