[en] Here in this paper we report an IR-IR double resonance study of the structural landscape present in the Na⁺(glucose) complex. Our experimental approach involves minimal modifications to a typical IR predissociation setup, and can be carried out via ion-dip or isomer-burning methods, providing additional flexibility to suit different experimental needs. In the current study, the single-laser IR predissociation spectrum of Na⁺(glucose), which clearly indicates contributions from multiple structures, was experimentally disentangled to reveal the presence of three α-conformers and five β-conformers. Comparisons with calculations show that these eight conformations correspond to the lowest energy gas-phase structures with distinctive Na+ coordination.

No abstract available

[en] A series of naturally occurring cardenolides that exhibit potent anti-transmissible gastroenteritis virus (TGEV) activity in swine testicular (ST) cells has been identified. In an immunofluorescence assay, these cardenolides were found to diminish the expressions of TGEV nucleocapsid and spike protein, which was used as an indication for viral replication; block TGEV infection induced apoptosis and cytopathic effects; and impart the same trend of inhibitory activity against Na⁺/K⁺-ATPase as for anti-TGEV activity. The viral titer inhibition was found to take place in a dose-dependent manner. Knocking down expression of Na⁺/K⁺-ATPase, the cellular receptor of cardenolides, in ST cells was found to significantly impair the susceptibility of ST cells to TGEV infectivity. Thus, we have identified Na⁺/K⁺-ATPase as an anti-viral drug target and its antagonists, cardenolides, a novel class of anti- TGEV agents. - Highlights: • Cardenolides were identified as a novel class of anti-TGEV agents. • Cardenolides diminished TGEV replication/viral titers in a dose dependent manner. • Cardenolides blocked TGEV infection induced apoptosis and cytopathic effect. • These cardenolides imparted the same trend of inhibitory activity for Na⁺/K⁺-ATPase. • Na⁺/K⁺-ATPase was identified as an anti-viral drug target.

[en] Highlights: • Seven Sleeping Beauties were identified in Paul Hagenmuller's work. • Sleeping Beauties are papers with delayed recognition in terms of citations. • The Sleeping Beauties relate to work on silicon clathrate, sodium cobaltate, and sodium-ion battery research. • The occurrence of Sleeping Beauties challenges the use of short-term citation-based metrics for the evaluation of scientific impact. - Abstract: Paul Hagenmuller (1921−2017) is an important figure of French solid-state chemistry, who enjoyed scientific and institutional recognition. He published 796 papers and has been cited more than 16,000 times. This paper explores Hagenmuller's work using scientometric analysis to reveal the impact of his work, his main research topics and his collaborations. Although Hagenmuller was a recognized scientist, a subset of his work, now highly cited, attracted little attention at the time of publication. To understand this phenomenon, we detect and study papers with delayed recognition, also called 'Sleeping Beauties' (SBs). In scientometrics, SBs are publications that go unnoticed, or 'sleep' for a long time before suddenly attracting a lot of attention in terms of citations. We identify 7 SBs published between 1965 and 1985, and awakened between 1993 and 2010. The first SB reports the discovery of the clathrate structure of silicon. The second reports the isolation of four new phases with the formula Na_xCoO₂ (x < =1). The five other SBs investigate the electrochemical intercalation and deintercalation of sodium, and the structure and properties of layered oxides. Through interviews with his coworkers, we attempt to identify the reasons for the delayed recognition and the context of the renewed interest in those papers.

[en] Rice classified as susceptible to salinity, especially at the seedling stage. To improve the salinity tolerance, one of the methods used is through seed priming. This study aims to figure out the effect of seed priming with NaCl on the seedling of Banyuasin and IR 64 varieties growth under salinity stress (1.2 m/s). The research was conducted in the Laboratory of Plant Science, Faculty of Agriculture, Ehime University, Japan using an experiment with clustered randomized design pattern. There were eight package of treatment, including V1H0M0, V1H0M1, V1H1M0, V1H1M1, V2H0M0, V2H0M1, V2H1M0, and V2H1M1 (V1: IR 64 variety, V2: Banyuasin variety, H0: Seeds without priming, H1: Seeds with priming, M0: non-saline media. M1: saline media of 1.2 m/s). Each treatment was replicated three times resulting in 24 units of the experiment. The results showed that salinity suppressed seedling growth. Even though primed Banyuasin seeds showed the best results for the variables mean of plant height, root length, shoot biomass, root biomass, and plant biomass, (34.27 cm, 19.03 cm, 0.81 g, 0.18g, and 0.99 g) under salinity stress, these results were not statistically different from any other treatment under the same growth condition. We suspected that the salinity level of the media was too high so that even primed seeds are unable to overcome the stress. This study also showed that primed Banyuasin seeds growth under salinity stress can maintain the lowest Na⁺ ions accumulation in the shoot (2.33 mg g^-1), and these results were significantly different with any other treatment under the same condition. This data indicated that seed priming enhances plant ability to maintain lower Na⁺ accumulation in a shoot, that is crucial to overcome salinity and to improve tolerance to salinity stress. (paper)

[en] Fundamental characterization of battery electrolyte is crucial for rechargeable batteries. This work reports the chemical stability of sodium hexafluorophosphate (NaPF6)-based non-aqueous electrolytes containing different solvent mixtures (e.g., cyclic and acyclic carbonates) in the presence of water for Na-ion batteries. A degradation study is conducted using NaPF₆-based electrolytes, highlighting the effect of two electrolyte additives, 2,2,2-trifluoroethoxy-2,2,2-ethoxy phosphazene (FM2) and fluoroethylene carbonate (FEC), on degradation and cell performance of full-cell Na-ion batteries. Hydrolysis of this salt in acidic condition is particularly prone to form hydrofluoric acid (HF), and can be observed in electrolytes made with battery grade carbonate solvents (<20 ppm of water). Here, degradation mechanisms of NaPF₆-based electrolytes are studied using liquid nuclear magnetic resonance (NMR). Noticeable degradation takes place in high purity electrolytes with the presence of moisture to form HF and organophosphates in timeframes below the current shelf-life of the Na electrolytes. FEC is not efficient to protect the electrodes from being exposed to HF. On the other hand, FM2 is revealed as a “scavenger” of HF, which helps stabilize the shelf life of electrolytes that might contain or become exposed to water. Our study underscores the importance to understanding the degradation of electrolyte and improving stability toward better shelf life for sodium ion batteries.

No abstract available

[en] Highlights: • With sodium ions insertion, MoS₂ will first experience layer expansion and then phase transformation and finally fragmentation after triggering conversion reaction. • With sodium ions insertion, the HER activity of MoS₂ will gradually increase at the intercalation stage and further increase at the early stage of conversion reaction and finally slightly decrease at the end of discharging. • The possible structure-performance relationship is established. -- Abstract: Though enormous attention has been paid to MoS₂ in the field of electrocatalytic hydrogen evolution reaction (HER), the conventional 2H MoS₂ is hardly regarded as an alternative to noble Pt due to the limited number of active sites and semiconducting character. Herein, sodium ions were intentionally introduced into the MoS₂ to regulate its structure and thus HER activity. We found that the HER activity of MoS₂ would gradually increase at the intercalation stage and further increase at the early stage of conversion reaction. Based on various characterization techniques, the possible structure-performance relationship was established. The first increase in activity was ascribed to interlayer expansion and phase transformation, and the second increase in activity was mainly ascribed to increase of active sites due to the fragmentation of MoS₂ after triggering conversion reaction. Even though deep discharging MoS₂ to 0.01 V (vs. Na⁺/Na) would slightly impair HER activity, such an activity was still much better than that of pristine MoS₂, which might be originated from the doping of S into molybdenum oxide according to the DFT calculation.

[en] A sodium ion- selective electrode based on dibenzopyridino-18-crown-6 as membrane carrier was successfully prepared. The electrode exhibits a Nernstian response for Na"+ ions within the concentration range of 1.0 x 10"-"4-1.0 x 10"-"1 M. The response time of the sensor is 20 s. The sodium ion-selective electrode exhibited comparatively good selectivities with respect to alkali, alkaline earth and some transition metal ions

[en] As a novel Na-ion battery anode, we studied electrochemical reactions of a LaSn₃ electrode, and evaluated its cycling performance by comparison with that of a SmSn₃ electrode. The LaSn₃ electrode showed a reversible capacity of 580 mA h cm⁻³ at the first cycle, and a gradual increase in the capacity with cycling number. The LaSn₃ electrode exhibited a high capacity of 1470 mA h cm⁻³ even at the 400th cycle, which is three times higher than that of a hard carbon electrode. The electrode reactions of elemental Sn were observed in a cyclic voltammetry profile of the LaSn₃ electrode, indicating that a phase separation of LaSn₃ gradually occurs to form Sn. We suggested that the phase separation provides a Na-inactive La₃Sn₅ matrix, which can suppress the aggregation of Sn particles and can improve the cyclability. On the other hand, the SmSn₃ electrode showed a higher initial capacity of 970 mA h cm⁻³ and an earlier capacity decay by the 200th cycle. It is suggested that the phase separation of SmSn₃ progresses more rapidly while that of LaSn₃ slowly occurs because of a higher thermodynamic stability for LaSn₃ than SmSn₃.