Search

Out-of-equilibrium electrochemical reaction mechanisms are notoriously difficult to characterize. However, such reactions are critical for a range of technological applications. For instance, in metal-ion batteries, spontaneous electrolyte degradation controls electrode passivation and battery cycle life. Here, to improve our ability to elucidate electrochemical reactivity, we for the first time combine computational chemical reaction network (CRN) analysis based on density functional theory (DFT) and differential electrochemical mass spectroscopy (DEMS) to study gas evolution from a model Mg-ion battery electrolyte─magnesium bistriflimide (Mg(TFSI)2) dissolved in diglyme (G2). Automated CRN analysis allows for the facile interpretation of DEMS data, revealing H2O, C2H4, and CH3OH as major products of G2 decomposition. These findings are further explained by identifying elementary mechanisms using DFT. While TFSI- is reactive at Mg electrodes, we find that it does not meaningfully contribute to gas evolution. The combined theoretical-experimental approach developed here provides a means to effectively predict electrolyte decomposition products and pathways when initially unknown.

The rational design of electrolytes has been a long-standing challenge in chemistry and materials science. In this work, we demonstrate a computational rationale for improving the performance of weakly coordinating electrolytes in currently challenging multivalent-ion battery applications, based on enhanced thermodynamic and kinetic stability against reductive decomposition. A series of fluorinated alkoxyborate and alkoxyaluminate salts are systematically examined based on their reduction and oxidation potentials and, motivated by NMR spectroscopy, detailed reductive decomposition pathways involving the breaking of Al/B-O, C-O, or C-F bonds are obtained. Based on the decomposition kinetics, the hexafluoro-tert-isopropoxy (hfip) ligand for borates and the trifluoro-tert-butoxy (tftb) ligand for aluminates are identified as promising ligands for constructing the salt anions. This borate prediction corroborates previous experimental work on Mg[B(hfip)4]2and Ca[B(hfip)4]2, in which excellent electrochemical properties were reported. We find that steric factors govern the B-O bond-breaking decomposition kinetics while electronic factors are more important for aluminate salts. There is more charge transfer character in the aluminate transition states compared with borates for Al/B-O bond-breaking decomposition and thus electron-withdrawing ligands tend to stabilize the aluminate transition states. Such molecular-level understandings allow for better design principles for developing new electrolytes with improved stability and performance.

With the development of high-frequency carriers and high-capacity communications, ultrahigh-speed spectrum analyzer based on all-optical methods has been demonstrated in many fields. Limited by current data processing algorithms, ultrahigh-speed spectrum analyzers based on time-lens, such as frequency-domain light intensity spectrum analyzer (f-LISA) and parametric spectro-temporal analyzer (PASTA), are not yet to automatically process acquired data, which hinders their practicality. In this paper, a frame segmentation algorithm based on time-domain waveform analysis is proposed to achieve the automatic data processing of these analyzers, which can directly generate the spectro-temporal image of the signal under test. In a single-soliton test based on the f-LISA platform, the algorithm achieves an accuracy of 93.28% when the soliton changes and 90.04% when the soliton is stable. And in this test, the single-frame processing time of the algorithm is 419us. We believe the proposed algorithm will facilitate the practical application of spectrum analyzers like f-LISA and PASTA and provide a reference for other real-time measurement schemes.

Abstract Background Chiloschista (Orchidaceae, Aeridinae) is an epiphytic leafless orchid that is mainly distributed in tropical or subtropical forest canopies. This rare and threatened orchid lacks molecular resources for phylogenetic and barcoding analysis. Therefore, we sequenced and assembled seven complete plastomes of Chiloschista to analyse the plastome characteristics and phylogenetic relationships and conduct a barcoding investigation. Results We are the first to publish seven Chiloschista plastomes, which possessed the typical quadripartite structure and ranged from 143,233 bp to 145,463 bp in size. The plastomes all contained 120 genes, consisting of 74 protein-coding genes, 38 tRNA genes and eight rRNA genes. The ndh genes were pseudogenes or lost in the genus, and the genes petG and psbF were under positive selection. The seven Chiloschista plastomes displayed stable plastome structures with no large inversions or rearrangements. A total of 14 small inversions (SIs) were identified in the seven Chiloschista plastomes but were all similar within the genus. Six noncoding mutational hotspots (trnN GUU –rpl32 > rpoB–trnC GCA > psbK–psbI > psaC–rps15 > trnE UUC –trnT GGU > accD–psaI) and five coding sequences (ycf1 > rps15 > matK > psbK > ccsA) were selected as potential barcodes based on nucleotide diversity and species discrimination analysis, which suggested that the potential barcode ycf1 was most suitable for species discrimination. A total of 47–56 SSRs and 11–14 long repeats (> 20 bp) were identified in Chiloschista plastomes, and they were mostly located in the large single copy intergenic region. Phylogenetic analysis indicated that Chiloschista was monophyletic. It was clustered with Phalaenopsis and formed the basic clade of the subtribe Aeridinae with a moderate support value. The results also showed that seven Chiloschista species were divided into three major clades with full support. Conclusion This study was the first to analyse the plastome characteristics of the genus Chiloschista in Orchidaceae, and the results showed that Chiloschista plastomes have conserved plastome structures. Based on the plastome hotspots of nucleotide diversity, several genes and noncoding regions are suitable for phylogenetic and population studies. Chiloschista may provide an ideal system to investigate the dynamics of plastome evolution and DNA barcoding investigation for orchid studies.

Synotis jinpingensis (Asteraceae, Senecioneae), a new species from Jinping county in southeastern Yunnan province, China, is described and illustrated. This species is distinguished by having white ray florets in the genus Synotis, in which only species with yellow ray florets have been hitherto known. In habit and leaf shape S. jinpingensis is most closely similar to S. duclouxii, a species occurring in southwestern Guizhou, southern Sichuan and northeastern Yunnan, China, but differs, in addition to the color of ray florets, by having fewer lateral veins of leaves, obviously longer bracts of calyculus, and larger phyllaries. The membership of the new species within Synotis is strongly corroborated by evidence from floral micromorphology and phylogenetic analyses based on ITS sequence data. Color photographs of living plants, a distribution map, and provisional IUCN status of S. jinpingensis are provided.

Public participation in architectural heritage protection is a crucial part of promoting the development of heritage conservation. However, even in the same country, different regions protect heritage at different levels. This study, taking national wooden arch corridor bridges as the research object, analyzes the public participation level in wooden arch corridor bridge protection in the last 5 years, studying the factors that influence public participation and the change in rules of public participation caused by geography, providing a theoretical reference for the sustainable development of the protection of wooden arch corridor bridges. The results indicate (1) public participation in the protection of wooden arch corridor bridges has been increasing annually under government guidance; (2) there is a positive correlation between the concentration of wooden arch corridor bridges and the level of public participation; (3) the better the planning is regarding wooden arch corridor bridges and their surrounding areas, the higher the level of public participation, while the lower the level of residents’ participation and willing; (4) the higher the development and better the transportation in the areas where wooden arch corridor bridges are located, the higher the level of public participation; and (5) increasing the popularity of wooden arch corridor bridges, as well as the areas they are located in, can enhance public participation. These conclusions and research methods also provide methodological guidance and theoretical support for other public participation in the study of architectural heritage.

Mathematical models have many applications in infectious diseases: epidemiologists use them to forecast outbreaks and design containment strategies; systems biologists use them to study complex processes sustaining pathogens, from the metabolic networks empowering microbial cells to ecological networks in the microbiome that protects its host. Here, we (1) review important models relevant to infectious diseases, (2) draw parallels among models ranging widely in scale. We end by discussing a minimal set of information for a model to promote its use by others and to enable predictions that help us better fight pathogens and the diseases they cause.

Synthetic cathinones have gained increasing popularity in the illicit drug market, yet their abuse potential remains poorly understood. In this study, zebrafish were used to compare the addictive potential of three cathinone analogs, namely pentylone, eutylone, and N-ethylpentylone (NEP). The zebrafish received various doses (0 to 60 mg/kg) of the cathinone analogs by oral gavage over two sessions per day for two consecutive days to induce conditioned place preference (CPP). Pentylone, eutylone, and NEP dose-dependently induced CPP, with NEP showing significantly higher CPP than pentylone and eutylone at the dose of 20 mg/kg. The fish that received 60 mg/kg of cathinones underwent extinction, followed by reinstatement triggered by drug priming. NEP required six sessions to meet the criteria of extinction, followed by eutylone, which required four sessions, and pentylone, which required three sessions. Furthermore, NEP and eutylone at a dose of 40 mg/kg could reinstate the extinguished CPP, while 60 mg/kg of pentylone was necessary for CPP reinstatement. The persistence of susceptibility to reinstatement was also assessed at 7 and 14 days after the initial reinstatement. The CPP induced by all three cathinone analogs could be reinstated 7 days after the initial reinstatement, whereas only CPP induced by NEP, but not pentylone and eutylone, could be reinstated again after 14 days. Considering the potency to induce CPP, resistance to extinction, and the propensity for reinstatement, the abuse liability rank order of the cathinone analogs might be as follows: NEP > eutylone > pentylone. These findings suggest that the zebrafish CPP paradigm can serve as a viable model for assessing the relative abuse liability of substances.

The splicing design of the existing road and the new road in the expansion project is an important part of the design work. Based on the analysis of the characteristics and the load effect of pavement structure on splicing, this paper points out that tensile crack or shear failure may occur at the splicing under the repeated action of the traffic load on the new/old pavement. According to the current structure design code of asphalt pavement in China, it is proposed that the horizontal tensile stress at the bottom of the splicing layer and the vertical shear stress at other layers of the splicing line should be controlled by adjusting the position and size of the excavated steps in addition to the conventional design index, and put forward the corresponding technical requirements and design process. It can be used for reference in the design of asphalt pavement reconstruction and expansion projects.

A promising high-voltage spinel oxide cathode material MgCrMnO4 with 18% Mg/Mn inversion was synthesized successfully. A new custom operando battery device was designed to study the cation migration mechanisms of the MgCrMnO4 cathode using 0.1 M Mg(TPFA)2 electrolyte dissolved in triglyme and activated carbon as the anode. For the first time in multivalent batteries, high-quality operando diffraction data enabled the accurate quantification of cation contents in the host structure. Besides the exceptional reversibility of 12% Mg2+ insertion in Mg1-xCrMnO4 (x ≤ 1), a partially reversible insertion of excess Mg2+ during overdischarging was also observed. Moreover, the insertion/extraction reaction was experimentally shown to be accompanied by a series of cation redistributions in the spinel framework, which were further supported by density functional theory calculations. The inverted Mn is believed to be directly involved in the cation migrations, which would cause voltage hysteresis and irreversible structural evolution after overdischarging. Tuning the Mg/Mn inversion rate could provide a direct path to further optimize spinel oxide cathodes for Mg-ion batteries, and more generally, the operando techniques developed in this work should play a key role in understanding the complex mechanisms involved in multivalent ion insertion systems.