Polyoxometalates (POMs), anionic metal‐oxygen nanoclusters that possess various composition‐dependent properties, are widely used to modify the existing properties of metal nanoparticles and to endow ...them with new ones. Herein, we present an overview of recent advances in hybrid materials that consist of metal nanoparticles and POMs. Following a brief introduction on the inception of this area and its development, representative properties and applications of these materials in various fields such as electrochemistry, photochemistry, and catalysis are introduced. We discuss how the combination of two classic inorganic materials facilitates cooperative and synergistic behavior, and we also give personal perspectives on the future development of this field.
Hybrid materials that consist of metal nanoparticles and polyoxometalates have enormous potential in a multitude of applications, including electrochemistry, photochemistry, catalysis, biochemistry, and surface‐enhanced Raman scattering (SERS). This Minireview highlights recent advances in this area, covering synthesis and applications as well as highlighting current limitations and future research opportunities.
A classic problem in microbiology is that bacteria display two types of growth behavior when cultured on a mixture of two carbon sources: the two sources are sequentially consumed one after another ...(diauxie) or they are simultaneously consumed (co-utilization). The search for the molecular mechanism of diauxie led to the discovery of the lac operon. However, questions remain as why microbes would bother to have different strategies of taking up nutrients. Here we show that diauxie versus co-utilization can be understood from the topological features of the metabolic network. A model of optimal allocation of protein resources quantitatively explains why and how the cell makes the choice. In case of co-utilization, the model predicts the percentage of each carbon source in supplying the amino acid pools, which is quantitatively verified by experiments. Our work solves a long-standing puzzle and provides a quantitative framework for the carbon source utilization of microbes.
To respond to the increasing demands for practical applications, stabilization and property modulation of metal nanoparticles have emerged as a key research subject. Herein, we present a viable ...protocol for preparing small metal nanoparticles (<5 nm; Ag, Pd, Pt, and Ru)
via
multidentate polyoxometalate (POM, SiW
9
O
34
10−
) modification. In addition to enhancing stability, the POMs can modulate the electronic states of metal nanoparticles. Moreover, immobilization of the POM-modified metal nanoparticles on solid supports enables further tuning of the electronic states
via
a cooperative effect between the POMs and the supports without altering the particle size. Notably, POM-modified Pd nanoparticles on carbon support exhibited superior catalytic activity and selectivity in hydrogenation reactions in comparison with the catalyst without the POM modification.
We present a protocol for preparing metal nanoparticles (<5 nm; Ag, Pd, Pt, and Ru)
via
multidentate polyoxometalate (POM) modification with enhanced stability and catalytic activity. The electronic states can be modulated by POMs and supports.
Motivated by the positive psychology movement in the English as Foreign Language (EFL), existing studies have demonstrated that subject-related enjoyment has a positive correlation with academic ...achievement. However, quite a few studieshave examined why academic enjoyment can predict positive academic achievement. This study aimed to investigate whether behavioral engagement, self-concept, and organizational strategy mediated relations between academic enjoyment and achievement in EFL setting. 528 Chinese secondary school students (Male: N = 280; Female: N = 248) participated in the survey and completed the questionnaires on EFL-related enjoyment, behavioral engagement, self-concept, organizational strategy, and academic performance. Structural equation model (SEM) analyses showed that students' academic enjoyment positively predicted their English achievement. Academic engagement, self-concept, and organizational strategy had parallel multiple mediating effects between academic enjoyment and English achievement. Multi-group SEM analysis demonstrated that the model had invariance across genders, indicating that the model is applicable to both male and female students. Limitations and implications are discussed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Monazite is a naturally occurring lanthanide (Ln) phosphate mineral Ln
x(PO4)
y and is the main industrial source of the rare earth elements (REE), cerium and lanthanum. Endeavours to ensure ...the security of supply of elements critical to modern technologies view bioprocessing as a promising alternative or adjunct to new methods of element recovery. However, relatively little is known about microbial interactions with REE. Fungi are important geoactive agents in the terrestrial environment and well known for properties of mineral transformations, particularly phosphate solubilization. Accordingly, this research examined the capability of a ubiquitous geoactive soil fungus, Aspergillus niger, to affect the mobility of REE in monazite and identify possible mechanisms for biorecovery. It was found that A. niger could grow in the presence of monazite and mediated the formation of secondary Ce and La‐containing biominerals with distinct morphologies including thin sheets, orthorhombic tablets, acicular needles, and rosette aggregates which were identified as cerium oxalate decahydrate (Ce2(C2O4)3·10H2O) and lanthanum oxalate decahydrate (La2(C2O4)3·10H2O). In order to identify a means for biorecovery of REE via oxalate precipitation the bioleaching and bioprecipitation potential of biomass‐free spent culture supernatants was investigated. Although such indirect bioleaching of REE was low from the monazite with maximal lanthanide release reaching >40 mg L−1, leached REE were efficiently precipitated as Ce and La oxalates of high purity, and did not contain Nd, Pr and Ba, present in the original monazite. Geochemical modelling of the speciation of oxalates and phosphates in the reaction system confirmed that pure Ln oxalates can be formed under a wide range of chemical conditions. These findings provide fundamental knowledge about the interactions with and biotransformation of REE present in a natural mineral resource and indicate the potential of oxalate bioprecipitation as a means for efficient biorecovery of REE from solution.
This paper presents the results of experimental investigations on the permeability of basalt fibre engineered cementitious composite (BF-ECC) in terms of water absorption and chloride resistance. ...Cylindrical specimens with five fibre volume fractions (0.0, 0.5, 1.0, 1.5 and 2.0%) were prepared and cured for 28 or 56 days. The water absorption, charge passed, chloride diffusion coefficient, microstructure and pore structure were determined. Macro-test results showed that BF could enhance the ability of ECC to resist water and chloride ions penetration, and this positive effect was weakened as fibre volume climbed. Microstructure indicated that the presence of BF restricted the progradation of microcracks in the matrix, nonetheless, the debonding and entangling of fibres at fibre fractions of 1.5% and 2.0% were captured, accompanied by visible cracks and voids. Also, the addition of BF decreased the number of pores in the range of 10 nm to 100 nm, and the most critical pore was decreased. Incorporating 1.0% BF decreased the porosity of ECC, while the addition of 2.0% BF increased. Herein the paper, BF-ECC with a 1.0% fibre volume fraction is preferred.
Accurate remaining useful life prediction is meaningful for cutting tool usability evaluation. Over the years, experience-based models, data-driven models, and physics-based models have been used ...individually to predict cutting tool remaining useful lives. In order to improve prediction performances, different prognostics models can be combined to leverage their advantages. In this paper, a hybrid cutting tool remaining useful life prediction approach is proposed by combining a data-driven model and a physics-based model. By using force, vibration and acoustic emission signals, the data-driven model monitors cutting tool wear conditions based on empirical mode decomposition and back propagation neural network. On the basis of the Wiener process, the physics-based model builds a cutting tool condition degradation model to predict cutting tool remaining useful lives. Experimental study verifies the approach's effectiveness, accuracy, and robustness. Then, cutting tool remaining useful lives can be predicted more accurately during the machining process.
The spread of antibiotic resistance is a growing public health concern. While numerous studies have highlighted the importance of environmental sources and pathways of the spread of antibiotic ...resistance, a systematic means of comparing and prioritizing risks represented by various environmental compartments is lacking. Here, we introduce MetaCompare, a publicly available tool for ranking 'resistome risk', which we define as the potential for antibiotic resistance genes (ARGs) to be associated with mobile genetic elements (MGEs) and mobilize to pathogens based on metagenomic data. A computational pipeline was developed in which each ARG is evaluated based on relative abundance, mobility, and presence within a pathogen. This is determined through the assembly of shotgun sequencing data and analysis of contigs containing ARGs to determine if they contain sequence similarity to MGEs or human pathogens. Based on the assembled metagenomes, samples are projected into a 3-dimensionalhazard space and assigned resistome risk scores. To validate, we tested previously published metagenomic data derived from distinct aquatic environments. Based on unsupervised machine learning, the test samples clustered in the hazard space in a manner consistent with their origin. The derived scores produced a well-resolved ascending resistome risk ranking of: wastewater treatment plant effluent, dairy lagoon, and hospital sewage.
Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS) is a common and serious disease with unclear pathogenesis and recurrent symptoms. Hedyotis diffusa Willd (HDW) has been recognized for its ...potential in managing various chronic inflammatory diseases. This research aimed to interrogate the mechanism of HDW in treating CP/CPPS. Complete Freund Adjuvant (CFA) and LPS were utilized to establish the rat and cell models of CP/CPPS. Results showed that HDW decreased levels of inflammation‐related factors in CP rat prostate tissue and LPS‐elicited RWPE‐1 cell injury model. Moreover, HDW administration impaired oxidative stress in the prostate and RWPE‐1 cells. In addition, HDW treatment activated the NRF2/ARE signaling in rat prostate tissue and cell models. Interestingly, NRF2/ARE pathway inhibitor ML385 reversed the inhibition effects of cell apoptosis, inflammation, and oxidative stress triggered by HDW. In summary, HDW alleviated inflammation and oxidative stress by activating NRF2/ARE signaling in CP/CPPS rat model and human prostate epithelial cell injury model.
Although supported anionic gold nanoparticle catalysts have been theoretically investigated for their efficacy in activating O2 in aerobic oxidation reactions, limited studies have been reported due ...to the difficulty of designing these catalysts. Herein, we developed a feasible method for preparing supported anionic gold nanoparticle catalysts using multivacant lacunary polyoxometalates with high negative charges. We confirmed the strong and robust electronic interaction between gold nanoparticles and multivacant lacunary polyoxometalates, and the electronic states of the supported gold nanoparticle catalysts can be sequentially modulated. Particularly, the catalyst prepared using SiW9O3410− acted as an efficient reusable heterogeneous catalyst, showing superior catalytic performance for the oxidative dehydrogenation of piperidone derivatives to the corresponding enaminones and remarkably higher stability than supported gold nanoparticle catalysts without this modification.
A method is reported for the design of supported anionic gold nanoparticle catalysts modified using highly negatively charged multivacant lacunary polyoxometalates. Enhanced catalytic activity and stability of supported anionic gold nanoparticle catalysts was accessed in the aerobic oxidative dehydrogenation of piperidone derivatives to the corresponding enaminones.
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