Abstract
Chemical fixation of carbon dioxide (CO
2
) may be a pathway to retard the current trend of rapid global warming. However, the current economic cost of chemical fixation remains high because ...the chemical fixation of CO
2
usually requires high temperature or high pressure. The rational design of an efficient catalyst that works at ambient conditions might substantially reduce the economic cost of fixation. Here, we report the rational design of covalent organic frameworks (COFs) as efficient CO
2
fixation catalysts under ambient conditions based on the finding of “pore enrichment”, which is concluded by a detailed investigation of the 10994 COFs. The best predicted COF, Zn-Salen-COF-SDU113, is synthesized, and its efficient catalytic performance for CO
2
cycloaddition to terminal epoxide is confirmed with a yield of 98.2% and turnover number (TON) of 3068.9 under ambient conditions, which is comparable to the reported leading catalysts. Moreover, this COF achieves the cycloaddition of CO
2
to 2,3-epoxybutane under ambient conditions among all porous materials. This work provides a strategy for designing porous catalysts in the economic fixation of carbon dioxide.
The novel coronavirus infection that initially found at the end of 2019 has attracted great attention. So far, the number of infectious cases has increased globally to more than 100 thousand and the ...outbreak has been defined as a pandemic situation, but there are still no “specific drug” available. Relevant reports have pointed out the novel coronavirus has 80% homology with SARS. In the difficulty where new synthesized drug cannot be applied immediately to patients, “conventional drug in new use” becomes a feasible solution. The first medication experience of the recovered patients in the US has led remdesivir to be the “specific drug”. China has also taken immediate action to put remdesivir into clinical trials with the purpose of applying it into clinical therapeutics for Corona Virus Disease 2019 (COVID-19). We started from the structure, immunogenicity, and pathogenesis of coronavirus infections of the novel coronavirus. Further, we analyzed the pharmacological actions and previous trials of remdesivir to identify the feasibility of conducting experiments on COVID-19.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Integrating a molecular catalyst with a light harvester into a photocatalyst is an effective strategy for solar light conversion. However, it is challenging to establish a crystallized framework with ...well‐organized connections that favour charge separation and transfer. Herein, we report the heterogenization of a Salen metal complex molecular catalyst into a rigid covalent organic framework (COF) through covalent linkage with the light‐harvesting unit of pyrene for photocatalytic hydrogen evolution. The chemically conjugated bonds between the two units contribute to fast photogenerated electron transfer and thereby promote the proton reduction reaction. The Salen cobalt‐based COF showed the best hydrogen evolution activity (1378 μmol g−1 h−1), which is superior to the previously reported nonnoble metal based COF photocatalysts. This work provides a strategy to construct atom‐efficient photocatalysts by the heterogenization of molecular catalysts into covalent organic frameworks.
The heterogenization of a Salen metal complex molecular catalyst into a rigid covalent organic framework (COF) through covalent linkage with the light‐harvesting unit of pyrene for photocatalytic hydrogen evolution is reported. Co/Zn‐Salen‐COF showed the best hydrogen evolution activity (1378 μmol g−1 h−1), which is superior to the previously reported non‐noble metal‐based COF photocatalysts
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
is a Chinese endemic genus comprising two species,
and
. In this study, we sequenced the complete chloroplast (cp) genomes of these two species and of their relative
. Illumina sequencing technology ...was used to compare sequences, elucidate the intra- and interspecies variations, and infer the phylogeny relationship with other Ranunculaceae family species. A typical quadripartite structure was detected, with a genome size from 158,473 to 158,512 bp, consisting of a pair of inverted repeats separated by a small single-copy region and a large single-copy region. We analyzed the nucleotide diversity and repeated sequences components and conducted a positive selection analysis by the codon-based substitution on single-copy coding sequence (CDS). Seven regions were found to possess relatively high nucleotide diversity, and numerous variable repeats and simple sequence repeats (SSR) markers were detected. Six single-copy genes (
,
,
,
,
, and
) resulted to have high posterior probabilities of codon sites in the positive selection analysis, which means that the six genes may be under a great selection pressure. The visualization results of the six genes showed that the amino acid properties across each column of all species are variable in different genera. All these regions with high nucleotide diversity, abundant repeats, and under positive selection will provide potential plastid markers for further taxonomic, phylogenetic, and population genetics studies in
and its relatives. Phylogenetic analyses based on the 79 single-copy genes, the whole complete genome sequences, and all CDS sequences showed same topologies with high support, and
was closely clustered with
within the
genus, with
as their closest relative. Therefore, the complete cp genomes in
species provide interesting insights and valuable information that can be used to identify related species and reconstruct their phylogeny.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Roots are the interfaces between biochar particles and growing plants. Biochar application may alter root growth and traits and thereby affect plant performance. However, a comprehensive ...understanding of the effects of biochar on root traits is lacking. We conducted a meta‐analysis with 2108 paired observations from 136 articles to evaluate the responses of root traits associated with 13 variables under biochar application. Overall, biochar application increased root biomass (+32%), root volume (+29%) and surface area (39%). The biochar‐induced increases in root length (+52%) and number of root tips (+17%) were much larger than the increase in root diameter (+9.9%); this result suggests that biochar application benefits root morphological development to alleviate plant nutrient and water deficiency rather than to maximize biomass accumulation. Biochar application did not change root N concentration but significantly increased root P concentration (+22%), particularly when combined with N fertilization. Biochar application also affected root‐associated microbes and significantly increased the number of root nodules (+25%). The responses of root traits to biochar application were generally greater in annual plants than in perennial plants and were affected by soil texture and pH values. Moreover, it appears that biochar production process (pyrolysis temperature and time) plays a more important role in regulating root growth than does biochar source. Together, findings obtained from this meta‐analysis may have significant implications for the future sustainable development of biochar management to improve plant growth and functioning.
To future sustainable biochar management, a comprehensive meta‐analysis with 2108 paired observations from 136 articles was conducted to evaluate responses of root traits associated with 13 variables under biochar application. Overall, biochar application significantly improved root growth and morphology, in particular, with overall stronger stimulation on root length than root diameter, which would benefit root morphological development to alleviate plant nutrient and water deficiency rather than to maximize biomass accumulation. Moreover, the responses of root traits to biochar application were affected by fertilizer input, plant species, soil pH and texture, and biochar production process.
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BFBNIB, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
This paper discusses the results of a corpus-based study on the usage and functions of the western loanword sutoppu and its synonymous Sino-Japanese, teishi. Our analyses focus on the following four ...perspectives: (1) frequency, (2) conjugation types, (3) characteristics of genres used, and (4) collocations. The results show that sutoppu is used mostly in a causative form, implying something compulsory or intentional, whereas teishi is mostly used in its passive form to imply inevitability. In addition, sutoppu emphasizes instantaneity and has the meaning of intentionally stopping something with great resistance. Whereas teishi permits a certain duration of time and describes the state of being stopped.
•Elite particles in the population are selected based on the target value of the particles and the mutual distance between the particles.•Based on a unique small group of particles and the nearest ...three particles, all particles are close to the local elite particles to find multiple global peaks. The final solution has very high accuracy.
Niching is an important technique for multimodal optimization. Most existing niching methods require specification of certain niching parameters in order to perform well. But these parameters are usually difficult to set because they depend on the problem. The particle swarm optimization algorithm using the ring neighborhood topology does not require any niche parameters, but the determination of the particle neighborhood in this method is based on the subscript of the particle, and the result fails to achieve the best performance. For better performance, in this paper, a particle swarm optimization algorithm based on the ring neighborhood topology of Euclidean distance between particles is proposed, which is called the close neighbor mobility optimization algorithm. The algorithm mainly includes the following three strategies: elite selection mechanism, close neighbor mobility strategy and modified DE strategy. It mainly uses the Euclidean distance between particles. Each particle forms its own unique niche, evolves in a local scope, and finally locates multiple global optimal solutions with high precision. The algorithm greatly improves the accuracy of the particle. The experimental results show that the close neighbor mobility optimization algorithm has better performance than most single-objective multi-modal algorithms.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Exploring high‐performance electrocatalysts, especially non‐noble metal electrocatalysts, for the oxygen evolution reaction (OER) is critical to energy storage and conversion. Herein, we report for ...the first time that conjugated microporous polymers (CMPs) incorporating salen can be used as OER electrocatalysts with outstanding performances. The best OER electrocatalyst (salen‐CMP‐Fe‐3) exhibits a low Tafel slope of 63 mV dec−1 and an overpotential of 238 mV at 10 mA cm−2. DFT and Grand Canonical Monte Carlo calculations confirmed that the significantly improved electrocatalytic properties can be attributed to the intrinsic catalytic activity of the salen moiety and the enrichment effect of the pore structures. This work demonstrates that salen‐based conjugated polymers are a type of metal‐coordinated porous polymer that show excellent catalyst performance.
What a performance! Conjugated microporous polymer (CMP) frameworks incorporating metal–salen units have proven to be excellent candidates as high‐performance catalysts for the oxygen evolution reaction (see figure). Both DFT calculations and experimental studies have shown that the catalytic activity of the metal sites in the salen–CMP system declines in the order Fe > Co > Ni > Mn > V > Sc > Cu > Zn > Ti.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
For a class of Sierpinski-type self-affine measures on R2, a characterization for all maximal orthogonal sets of exponentials is given. By this characterization, a sufficient condition for a maximal ...orthogonal set to be a basis of L2(μ) is given.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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