Rational Engineering of p-n Heterogeneous ZnS/SnO2 Quantum Dots with Fast Ion Kinetics for Superior Li/Na-Ion Battery.

Constructing heterogeneous nanostructures is an efficient strategy to improve the electrical and ionic conductivity of metal chalcogenide-based anodes. Herein, ZnS/SnO2 quantum dots (QDs) as p-n heterojunctions that are uniformly anchored to reduced graphene oxides (ZnS-SnO2 @rGO) are designed and engineered. Combining the merits of fast electron transport via the internal electric field and a greatly shortened Li/Na ion diffusion pathway in the ZnS/SnO2 QDs (3-5 nm), along with the excellent electrical conductivity and good structural stability provided by the rGO matrix, the ZnS-SnO2 @rGO anode exhibits enhanced electronic and ionic conductivity, which can be proved by both experiments and theoretical calculations. Consequently, the ZnS-SnO2 @rGO anode shows a significantly improved rate performance that simple counterpart composite anodes cannot achieve. Specifically, high reversible specific capacities are achieved for both lithium-ion battery (551 mA h g-1 at 5.0 A g-1 , 670 mA h g-1 at 3.0 A g-1 after 1400 cycles) and sodium-ion battery (334 mA h g-1 at 5.0 A g-1 , 313 mA h g-1 at 1.0 A g-1 after 400 cycles). Thus, this strategy to build semiconductor metal sulfides/metal oxide heterostructures at the atomic scale may inspire the rational design of metal compounds for high-performance battery applications.

Embedding Lanthanide Organic Polyhedra into Mesoporous Silica Nanoparticles for the Photocatalytic Degradation of Organic Dyes.

Organic pollutants cause severe environmental problems because of their damage to human health and ecological systems. Photocatalytic degradation of persistent organic pollutants is of great importance to address these hazards. Herein, we report a lanthanide organic polyhedra-based hybrid material Gd8 L12 ⊂MSN with the capability of photocatalytic dye degradation. Gd8 L12 ⊂MSN was prepared by embedding the Gd8 L12 complex into mesoporous silica nanoparticles (MSNs) using a "ship-in-a-bottle" strategy. Photocurrent response tests revealed that this hybrid material is a potential semiconductor and could generate a rapid and steady photocurrent upon irradiation. Further dye degradation experiments indicated that it could photocatalyze the degradation of familiar organic dyes. Thereinto, compared with the critical Gd8 L12 complex, the hybrid material exhibited an acceleration of 2.4 times and realized reusability. This not only offers a potential advanced photocatalyst for degrading persistent organic pollutants, but also provides a strategy for the application of supramolecular materials in environmental science.

Preparation of ZnS@N-doped-carbon composites via a ZnS-amine precursor vacuum pyrolysis route.

ZnS/carbon nanocomposites have potential electrochemical applications due to their improved conductivity and more active sites through modification of the carbon materials. Herein, we report a facile method to synthesize the nanocomposites comprising ZnS nanoparticles and nitrogen-doped carbon (ZnS@NC). The inorganic-organic hybrid ZnS-amine material ZnS(ba) (ba = n-butylamine) is synthesized on a large scale by a reflux method, which effectively shortens the reaction time while maintaining the high yield compared with the solvothermal method. Then ZnS(ba) is used as precursor for obtaining ZnS@NC nanocomposites via a vacuum pyrolysis route, in which the content of carbon and nitrogen can be controlled by adjusting the pyrolysis temperature. Further, a series of ZnS-amine hybrid materials ZnS(ha), ZnS(en)0.5 and ZnS(pda)0.5 (ha = n-hexylamine; en = ethylenediamine; pda = 1,3-propanediamine) are synthesized and used as precursors for the preparation of ZnS@NC materials, indicating the universality of this method. Moreover, the as-synthesized ZnS@NC materials exhibit remarkable lithium storage performance with outstanding cycling stability, high-rate capability and remarkable pseudo-capacitance characteristics.

Impact of Resistance Training in Subjects With COPD: A Systematic Review and Meta-Analysis.

BACKGROUND: The goal of this study was to evaluate the effects of resistance training on subjects with COPD. METHODS: We performed a systematic search in MEDLINE, PubMed, Embase, CINAHL, Elsevier ScienceDirect, EBM Reviews, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov and also of leading respiratory journals for randomized controlled trials on COPD treatment for ≥ 4 weeks with resistance training compared with non-exercise control or with combined resistance and endurance training compared with endurance training alone. Data from these studies were pooled to calculate odds ratio and weighted mean differences (WMDs) with 95% CI. RESULTS: Eighteen trials with 750 subjects with advanced COPD met the inclusion criteria. There were 2 primary and 5 secondary outcomes. Compared with non-exercise control, resistance training led to significant improvements in the dyspnea domain of the Chronic Respiratory Disease Questionnaire (WMD of 0.59, 95% CI 0.26-0.93, I2 = 0%, P < .001), skeletal muscle strength, and percent-of-predicted FEV1 (WMD of 6.88%, 95% CI 0.41-13.35%, I2 = 0%, P = .04). The combination of resistance and endurance training significantly improved the St George Respiratory Questionnaire total score (WMD of -7.44, 95% CI -12.62 to -2.25, I2 = 0%, P = .005), each domain score, and skeletal muscle strength. There were no significant differences in 6-min walk distance, 6-min pegboard and ring test, maximum exercise work load, and maximum oxygen consumption between the 2 groups. There were no reports of adverse events related to resistance-training intervention. CONCLUSIONS: Resistance training can be successfully performed alone or in conjunction with endurance training without increased adverse events during pulmonary rehabilitation in COPD.