A Mechanistic Insight into the Oxygen Redox of Li-Rich Layered Cathodes and their Related Electronic/Atomic Behaviors Upon Cycling.

Li-rich cathodes are extensively investigated as their energy density is superior to Li stoichiometric cathode materials. In addition to the transition metal redox, this intriguing electrochemical performance originates from the redox reaction of the anionic sublattice. This new redox process, the so-called anionic redox or, more directly, oxygen redox in the case of oxides, almost doubles the energy density of Li-rich cathodes compared to conventional cathodes. Numerous theoretical and experimental investigations have thoroughly established the current understanding of the oxygen redox of Li-rich cathodes. However, different reports are occasionally contradictory, indicating that current knowledge remains incomplete. Moreover, several practical issues still hinder the real-world application of Li-rich cathodes. As these issues are related to phenomena resulting from the electronic to atomic evolution induced by unstable oxygen redox, a fundamental multiscale understanding is essential for solving the problem. In this review, the current mechanistic understanding of oxygen redox, the origin of the practical problems, and how current studies tackle the issues are summarized.

Detecting early-stage malignant melanoma using a calcium switch-enriched exosome subpopulation containing tumor markers as a sample.

An exosome species containing CD63 as a marker of melanoma was isolated from bulk exosome population and used as a sample for detecting malignant melanoma. A calcium binding protein (CBP) was produced and then used to raise monoclonal antibody. The antibody was sensitive to a conformational change of CBP caused by Ca2+ binding. Immuno-magnetic beads were prepared by immobilizing the conformation-sensitive binder and subsequent binding of CBP conjugated with the capture antibody specific to CD63. These immuno-beads were used to isolate CD63-positive exosome from a bulk exosome sample (normal or melanoma) based on the 'calcium switch-on/off' mechanism through magnetic separation. After recovery, the subpopulation sample was analyzed by immunoassays for cavelion1 (Cav1), CD81, and CD9 as sub-subpopulation markers. Normalized signals of Cav1 and/or CD81 over CD9 were higher in melanoma samples than in normal samples, depending on clinical stages (I, II, and IV) of patients. This was in contrast to assay results for the bulk exosome population that showed a completely mixed state of melanoma and normal samples. These results showed that an exosome subpopulation sample prepared using a 'Ca2+-dependent switch' technology might be useful for diagnosing malignant melanoma at an early stage to increase 5-year survival rates.

Treatment of refractory IgA vasculitis with dapsone: a systematic review.

IgA vasculitis, formerly known as Henoch-Schönlein purpura, is a systemic IgA-mediated vasculitis of the small vessels commonly seen in children. The natural history of IgA vasculitis is generally self-limiting; however, one-third of patients experience symptom recurrence and a refractory course. This systematic review examined the use of dapsone in refractory IgA vasculitis cases. A literature search of PubMed databases retrieved 13 articles published until June 14, 2018. The most common clinical feature was a palpable rash (100% of patients), followed by joint pain (69.2%). Treatment response within 1-2 days was observed in 6 of 26 patients (23.1%) versus within 3-7 days in 17 patients (65.4%). Relapse after treatment discontinuation was reported in 17 patients (65.4%) but not in 3 patients (11.5 %). Four of the 26 patients (15.4%) reported adverse effects of dapsone including arthralgia (7.7%), rash (7.7%), and dapsone hypersensitivity syndrome (3.8%). Our findings suggest that dapsone may affect refractory IgA vasculitis. Multicenter randomized placebo-controlled trials are necessary to determine the standard dosage of dapsone at initial or tapering of treatment in IgA vasculitis patients and evaluate whether dapsone has a significant benefit versus steroids or other medications.

Facile fabrication of porous ZnS nanostructures with a controlled amount of S vacancies for enhanced photocatalytic performances.

ZnS nanostructures of barbell-shaped porous and hollow nanoplates with a controlled amount of S vacancies have been facilely fabricated via the hydrothermal treatment of ZnS(en)0.5 (en = ethylenediamine) nanoplates. The amount of S vacancies as well as the morphologies of ZnS nanostructures have been controlled by adjusting the hydrolysis time; the layered structure of ZnS(en)0.5 nanoplates decomposes to yield discrete ZnS nanoparticles at two end facets of template nanoplates, producing barbell-shaped porous and hollow ZnS nanoplates with abundant S vacancies finally. The photocatalytic activity of ZnS nanostructures prepared via hydrolysis for 4 h is 8.2 times higher than that of commercial ZnS. The photocatalytic activity of ZnS nanostructures increases with the increase of emission at 390 nm arising from sulfur vacancies, suggesting that the high photocatalytic efficiency of ZnS nanostructures results mainly from the high amount of sulfur vacancies. Surface defects such as sulfur vacancies can trap photogenerated electrons to block the recombination of charges, enhancing the photocatalytic efficiency of the as-prepared ZnS nanostructures. It has also been found that both ˙OH and ˙O2- act as the major reactive species in the photocatalytic decomposition of rhodamine B via our prepared ZnS nanostructures. Barbell-shaped porous and hollow ZnS nanoplates are suggested to have great applicability to photocatalysts in waste-water treatment.

Impurity Location-Dependent Relaxation Dynamics of Cu:CdS Quantum Dots.

Various types of 2% Cu-incorporated CdS (Cu:CdS) quantum dots (QDs) with very similar sizes have been prepared via a water soluble colloidal method. The locations of Cu impurities in CdS host nanocrystals have been controlled by adopting three different synthetic ways of doping, exchange, and adsorption to understand the impurity location-dependent relaxation dynamics of charge carriers. The oxidation state of incorporated Cu impurities has been found to be +1 and the band-gap energy of Cu:CdS QDs decreases as Cu2S forms at the surfaces of CdS QDs. Broad and red-shifted emission with a large Stokes shift has been observed for Cu:CdS QDs as newly produced Cu-related defects become luminescent centers. The energetically favored hole trapping of thiol molecules, as well as the local environment, inhibits the radiative recombination processes of Cu:CdS QDs, thus resulting in low photoluminescence. Upon excitation, an electron is promoted to the conduction band, leaving a hole on the valence band. The hole is transferred to the Cu+ d-state, changing Cu+ into Cu2+, which then participates in radiative recombination with an electron. Electrons in the conduction band are ensnared into shallow-trap sites within 52 ns. The electrons can be further captured on the time scale of 260 ns into deep-trap sites, where electrons recombine with holes in 820 ns. Our in-depth analysis of carrier relaxation has shown that the possibilities of both nonradiative recombination and energy transfer to Cu impurities become high when Cu ions are located at the surface of CdS QDs.