The Monitoring and Cell Imaging of Fe3+ Using a Chromone-Based Fluorescence Probe.

A new structurally simple fluorescent CP probe based on chromone was designed and synthesized, and its structure was fully characterized using various analytical techniques. The CP probe displays a high selectivity and sensitivity for sensing Fe3+ with a "turn-off" fluorescence response over other metal ions in a DMSO/H2O (4:1, v/v) solution. The experiment results show that the CP probe is stable over a wide pH range of 2.0-12.0. The detection limit for Fe3+ was calculated to be 0.044 µmol•L-1. The molar ratio method indicated that the binding mode between the CP probe and Fe3+ is a 1:1 complex formation. HR-MS and density functional theory (DFT) calculations were also performed to further confirm the recognition mechanism. Both fluorescence imaging experiments and the MTT assay demonstrated that the CP probe was suitable for detecting intracellular Fe3+ and no significant cytotoxicity in living cells.

Affective Shifts Outside Work: Effects on Task Performance, Emotional Exhaustion, and Counterproductive Work Behavior.

Affective shifts have been linked to work attitudes and behaviors recently, but previous researches only focused on affective shift during work, with little attention to affective shifts outside work. Conservation of resources and personality system interaction theories are used to design a 2-week daily dairy study. Participants report how affective shifts outside work affect their subsequent-day task performance, emotional exhaustion, and CWB. As expected, findings indicate that shifts in affect outside work meaningfully impact job performance and work attitudes. That is, when both positive and negative affect upshift outside work, employees perform their tasks better but also experience increased emotional exhaustion. Practical implications and limitations are discussed.

Gastric floating tablet improves the bioavailability and reduces the hypokalemia effect of gossypol in vivo.

Gossypol (Gos) is a natural polyphenolic compound that has shown a number of valuable biological properties such as antifertility, antioxidation, and antitumor activities. However, the clinical application of Gos has been hindered by its notable adverse effects such as hypokalemia, hemolytic anemia, and so on. Using sustained-release dosage form provides a hopeful solution to this problem. In this study, a gastric floating tablet for sustained-release of Gos (Gos-GFT) was developed using polyvinylpyrrolidone, hydroxypropyl methyl cellulose, ethyl cellulose, lactose, sodium bicarbonate, and magnesium stearate. Gos-GFT had an average weight of around 200 mg with a drug content percentage of around 13.66%. The physicochemical properties of Gos-GFT satisfied the pharmacopoeial requirements for tablets. Gos-GFT was able to float in an acidic medium and had a sustained drug release for over 12 h. In vivo studies showed that the relative bioavailability of Gos-GFT, as compared with Gos powders, was larger than that of a non-gastric floating tablet which was a dosage form used for comparison with Gos-GFT. Furthermore, compared with the Gos powders and the non-gastric floating Gos tablets, Gos-GFT could prolong the in vivo action time of Gos, and significantly relieve hypokalemia which is a major adverse effect of Gos. These properties made Gos-GFT a promising Gos preparation that warrants further investigation for more extensive clinical applications of this natural compound.

Synthesis and Mechanism of High Structural Stability of Nickel-Rich Cathode Materials by Adjusting Li-Excess.

It has been a long-term challenge to improve the phase stability of Ni-rich LiNixMnyCo1-x-yO2 (x ≥ 0.6) transition metal (TM) oxides for large-scale applications. Herein, a new structure engineering strategy is utilized to optimize the structural arrangement of Li1+x(Ni0.88Mn0.06Co0.06)1-xO2 (NMC88) with a different Li-excess content. It was found that structure stability and particle sizes can be tuned with suitable Li-excess contents. NMC88 with an actual Li-excess of 2.7% (x = 0.027, Li/TM = 1.055) exhibits a high discharge capacity (209.1 mAh g-1 at 3.0-4.3 V, 0.1 C) and maintains 91.7% after the 100th cycle at 1 C compared with the NMC88 sample free of Li-excess. It also performs a delayed voltage decay and a good rate capacity, delivering 145.8 mAh g-1 at a high rate of 10 C. Multiscale characterization technologies including ex/in situ X-ray diffraction (XRD), focused ion beam (FIB) cutting-scanning electronic microscopy (SEM), and transmission electron microscopy (TEM) results show that a proper Li-excess (2.7%) content contributes to the formation of a broader Li slab, optimized cation mixing ratio, and even particle sizes. Therefore, NMC88 with a proper Li-excess is a good choice for next-generation cathode materials.

A sensitive BODIPY-based fluorescent probe for detecting endogenous hydroxyl radicals in living cells.

The hydroxyl radical (˙OH) has been suggested to play very vital roles in many physiological and pathological processes. However, selective detection of ˙OH is highly challenging owing to its extremely high reactivity and short lifetime. Herein, we designed and synthesized a sensitive "turn on" fluorescent probe for detecting endogenous ˙OH based on a BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) platform. The probe had shown good properties including high sensitively, ideal selectively and low cytotoxicity, and was successfully employed to image endogenous hydroxyl radical in living cells.

Synthesis and Redox Mechanism of Cation-Disordered, Rock-Salt Cathode-Material Li-Ni-Ti-Nb-O Compounds for a Li-Ion Battery.

Cation-disordered oxide materials working as cathodes for Li-ion batteries have been at a standstill because of their structurally limited specific capacities (below 175 mAh g-1 in most cases). In this work, we have introduced 4d0 Nb5+ into host material LiNi0.5Ti0.5O2 to synthesize Ni-based cation-disordered Fm3̅m Li-Ni-Ti-Nb-O compounds of Li1+x/100Ni1/2-x/100Ti1/2-x/100Nbx/100O2 (x = 0, 5, 10, 15, 20) through a sol-gel method, showing particle sizes of less than 200 nm. Taking Li1.2Ni0.3Ti0.3Nb0.2O2 with the best performance (an average voltage of ∼2.7 V and high discharge capacity of 221.5 mAh g-1) among oxides as a model, we study the relationship between the structure, morphology, redox mechanism, and electrochemical performance of cation-disordered oxides through a combination of X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption near-edge spectroscopy tests and in situ XRD with electrochemistry. The obtained results indicate that the improved capacity is mainly ascribed to Nb5+, which optimizes the Ni2+/Ni4+ practical capacity and effectively stabilizes the O2-/O- redox reaction. The results emphasize that Li-Ni-Ti-Nb-O compounds are promising members in the family of cation-disordered transition-metal oxide materials.

A Highly Selective NIR Fluorescent Turn-on Probe for Hydroxyl Radical and Its Application in Living Cell Images.

A highly selective NIR fluorescent turn-on probe for hydroxyl radical (·OH) has been built up using triphenylphosphine as a reactive-site for ·OH in an energy transfer cassette 2b consisting of 8-2'-(thiophen-2-yl) quinoline (TQ) as a donor and 3,5-diphenylphosphinostyryl-substituted BODIPY as an acceptor, which exhibits ca. 317 nm pseudo Stokes' shift due to efficient through-bond energy transfer (up to 169%). The triphenylphosphine substituent of 2b selectively oxidized by ·OH over the other reactive oxygen species (ROS) and the reactive nitrogen species (RNS) resulting in fluorescence enhancement in aqueous solution and in living cells.

A red fluorescent BODIPY probe for iridium (III) ion and its application in living cells.

A new red fluorescent probe 1 based on BODIPY skeleton has been successfully synthesized through introduction of 2-(thiophen-2-yl) quinoline moiety at meso- and 3-position, which exhibits excellent optical performance, including high fluorescence quantum yield, large pseudo Stokes' shift as well as high selectivity and sensitivity towards iridium (III) ion in aqueous solution and in living cells.

K2S2O8-Promoted Aryl Thioamides Synthesis from Aryl Aldehydes Using Thiourea as the Sulfur Source.

Thiourea as a sulfur atom transfer reagent was applied for the synthesis of aryl thioamides through a three-component coupling reaction with aryl aldehydes and N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMAC). The reaction could tolerate various functional groups and gave moderate to good yields of desired products under the transition-metal-free condition.

K2CO3-promoted formation of aryl esters from primary aryl amides by the acyl-acyl exchange process.

A new acyl-acyl exchange reaction has been developed for the formation of aryl esters from primary aryl amides. The reaction could occur under mild reaction conditions with catalytic quantities of K2CO3, and could afford moderate to good yields of the desired products.

A red fluorescent turn-on probe for hydrogen sulfide and its application in living cells.

A novel selective fluorescent chemosensor has been synthesized with a phenanthrene-fused dipyrromethene structure. Selective binding of Cu(2+) by results in a complex that displays high selectivity and sensitivity for H2S. The signal transduction occurs via reversible formation-separation of the complex and CuS. Its potential utility for biological applications was confirmed by fluorescence imaging of H2S in live cells.

Enhancing the Stokes' shift of BODIPY dyes via through-bond energy transfer and its application for Fe(3+)-detection in live cell imaging.

Two energy transfer cassettes that exhibit a large pseudo Stokes' shift (up to 400 nm) due to efficient through-bond energy transfer (up to 99%) have been constructed. Selective binding of Fe(III) with the donor entity significantly suppresses the excitation energy transfer resulting in fluorescence quenching in aqueous solution and in living cells.