Regulating the solid product growth is critical for achieving high capacities in rechargeable batteries based upon multiphase and multielectron dissolution–precipitation chemistries (e.g., ...lithium–sulfur chemistry). The intrinsic redox mediators, polysulfides, are insufficient for effective regulation due to the dynamically changed species and concentration. Herein cobaltocene (CoCp2) is introduced as a persistent extrinsic redox mediator to dictate an alternative growing pathway toward three‐dimensional lithium sulfide growth, which enables at most 8.1 times enhancement in discharge capacities at harsh conditions of high‐rate (>1 C) or electrolyte‐lean operation (electrolyte/sulfur ratio of 4.7 µL mgS−1). The faster kinetics and higher diffusivity of CoCp2 play an essential role in regulating lithium sulfide growth and increasing discharge capacities. This work not only illustrates an effective strategy to increase the capacity of high‐rate or electrolyte‐lean lithium–sulfur batteries but also paves a way toward the rational design of novel redox mediators for dissolution–precipitation energy chemistries.
The cobaltocene redox mediator is found to dictate an alternative growing pathway toward three‐dimensional lithium sulfide growth, which enabled at most 8.1 times enhancement in discharge capacities at harsh conditions of high‐rate or electrolyte‐lean operation. This work also paves a way toward the rational design of novel redox mediators for dissolution–precipitation energy chemistries.
Fast radio bursts (FRBs) are short-duration (∼millisecond) radio transients with cosmological origin. The simple sharp features of the FRB signal have been utilized to probe two fundamental laws of ...physics, namely, testing Einstein's weak equivalence principle and constraining the rest mass of the photon. Recently, Hessels et al. found that after correcting for dispersive delay, some of the bursts in FRB 121102 have complex time-frequency structures that include subpulses with a time-frequency downward drifting property. Using the delay time between subpulses in FRB 121102, here we show that the parameterized post-Newtonian parameter γ is the same for photons with different energies to the level of , which is 1000 times better than previous constraints from FRBs using similar methods. We also obtain a stringent constraint on the photon mass, mγ < 5.1 × 10−48 g, which is 10 times smaller than previous best limits on the photon mass derived through the velocity dispersion method.
The low permittivity of the polypropylene (PP) film has become a barrier for the further development of film capacitors with high energy storage density. An advanced strategy of the high-permittivity ...filler/polymer nanocomposite turns out to be a promising way of solving this problem. In this work, we coated ethylene propylene diene monomer (EPDM) as the shell on the surfaces of BaTiO3 successfully to fabricate core-shell structural nanoparticles. The addition of surface rubberized BaTiO3 into PP matrix promotes the permittivity to about 5.8, while the dielectric loss is barely changed as compared with PP itself. In addition, the elongation at break is as high as 364%, which is over 4 times higher than that of PP. The influences of shell thickness (3 nm, 5 nm and 7 nm) for the nanoparticles and hot-stretching process for the nanocomposite films were also carefully investigated, both of which greatly affected the properties of nanocomposites. Finally, the optimum breakdown strength as high as 370 MV/m is obtained, leading to a maximum energy density of 3.06 J/cm3, which can be attributed to both high breakdown strength and high permittivity of the core-shell structural BaTiO3/PP nanocomposites.
Display omitted
•Surface rubberized BaTiO3 was firstly added in PP to improve dielectric properties.•The influence of shell thickness for nanocomposites was investigated.•A hot-stretching process of films was carried out for practical applications.
Cobalt hydroxide nano-flakes are successfully synthesized by a facile chemical precipitation method. Electrochemical characterization is performed using cyclic voltammetry, chronopotentiometry and ...impedance spectroscopy, respectively. These cobalt hydroxide nano-flakes maintain high utilization at high rates of discharge. A maximum specific capacitance of 735
F
g
−1 can be achieved in 2
M aqueous KOH with the potential range from −0.2 to 0.4
V (vs. SCE) in a half-cell setup configuration for the nano-flakes Co(OH)
2 electrode, suggesting its potential application in electrochemical capacitors. Furthermore, the effect of annealing temperatures on the electrochemical capacitance characteristics is also been systematically explored.
Understanding the Type II Corrosion Mechanism Zhang, Wei-Jun; Sharghi-Moshtaghin, Reza
Metallurgical and materials transactions. A, Physical metallurgy and materials science,
04/2021, Volume:
52, Issue:
4
Journal Article
Peer reviewed
In a previous paper, the corrosion fronts of typical Type II corrosion pits observed on field parts were examined using the high-resolution transmission electron microscopy technique. A mixture of ...nanosized sulfides and oxides was observed in the pits, which suggests a solid-phase corrosion propagation process. In the present work, the corrosion products atop of the original alloy surface were characterized with an aim to understand the corrosion initiation process. A typical layered oxide structure was revealed comprising alternated NiO-rich and alumina-rich layers. Importantly, aluminum sulfate Al
2
(SO
4
)
3
was found to be present in the alumina-rich layers by chemistry and diffraction analyses. The co-existence of aluminum sulfate with alumina suggests that the original protective alumina-rich layer was likely attacked by a solid reaction under the unique aeroengine operation environment. No indication of molten NiSO
4
-Na
2
SO
4
mixture was identified in the corrosion pits or at the original metal/gas surface. The potential causes of lack of molten sulfate formation were discussed.
Summary
Objective
Thyroid cancer is the most common endocrine malignancy, and its incidence has been increasing over the last 30 years. Several studies have suggested that miRNAs may play a ...significant role in the differential diagnosis of indeterminate thyroid nodules. To systematically evaluate the utility of miRNAs in discriminating malignant thyroid nodules from benign ones on fine‐needle aspiration biopsy (FNAB) samples, a systematic review and meta‐analysis of the published literatures were carried out.
Patients and Design
Three hundred and sixty‐one samples, obtained from 341 patients, were included in the research, and summary sensitivities (SEN), specificities (SPE), positive likelihood ratios, negative likelihood ratios and diagnostic odds ratio were calculated. Then, summary receiver operating characteristic curves (SROCs) and areas under the SROC curves (AUCs) were calculated to further estimate the overall diagnostic value of miRNAs in thyroid cancer.
Results
The overall pooled SEN, SPE and AUC are 0·75, 0·81 and 0·89, respectively. For multiple miRNAs assays, the pooled SEN, SPE and AUC are 0·87, 0·75 and 0·68, respectively. For single miRNA assays, the corresponding results are 0·71, 0·84 and 0·87, respectively. The corresponding statistical results for differentiating indeterminate FNAB samples are 0·92, 0·68 and 0·86, respectively.
Conclusion
Our current meta‐analysis suggests that miRNAs may serve as a novel diagnostic tool in distinguishing malignant thyroid nodules from benign ones on FNAB specimens. In addition, subgroup analysis suggests that a panel of miRNAs may have a higher sensitivity but a relatively lower specificity than that of single miRNA in distinguishing thyroid nodules.
Objectives
Visceral leishmaniasis (VL) represents the most severe form of Leishmaniasis infection, often resulting in fatality without timely treatment. Previous studies have found that ...immunosuppression increases the risk of VL disease progression and mortality, and the total immunoglobulin G (IgG) levels in peripheral blood vary before and after treatment. However, the distinct levels and roles of IgG subclasses in VL have not been documented yet. This study aims to elucidate the characteristics and clinical significance of IgG subclasses in VL.
Methods
A total of 43 cases newly‐diagnosed with VL were enrolled in the cohort. We measured the levels of IgG subclasses before and after standard treatment and conducted assessments of bone marrow features. In addition, we analysed other haematological indices and examined the variations in IgG subclasses, as well as their correlation with clinical and laboratory factors.
Results
The levels of total IgG, IgG1, and the ratios of both IgG1/IgG and IgG1/IgG2 decreased significantly after treatment, whereas the ratios of IgG2/ IgG showed an obvious increase. The VL patients without hyperglobulinemia displayed significant lower IgG1/IgG2 ratios, but higher IgG2/IgG ratios compared with those with hyperglobulinemia. In addition, VL patients with positive bone marrow amastigotes had significant higher IgG1/IgG and IgG1/IgG2 ratios, but lower IgG2/IgG ratios. IgG subclasses were correlated with abnormal blood test results, particularly immunological elements including IgM and Complement 4 (C4).
Conclusions
IgG1 and IgG2 exhibited contrasting changes after treatment in VL patients. The features of bone marrow and laboratory tests indicated that IgG1 and IgG2 serve different roles in the progression of VL. The ratios of IgG subclasses may be more precise indicators to evaluate immune reaction in VL than traditional total IgG.
The co-existence of organic contaminants and heavy metals including 4-chlorophenol (4-CP) and Cr(VI) in aquatic system have become a challenging task in the wastewater treatment. Herein, the ...synchronous photocatalytic decomposition of 4-CP and Cr(VI) over new Z-scheme CoFe2O4/P–BiOBr heterojunction nanocomposites were revealed. In this work, the nanocomposites were successfully developed via a surfactant-free hydrothermal method. The heterojunction interface was created by decorating magnetic CoFe2O4 nanoparticles onto P–BiOBr nanosheets. The as-fabricated CoFe2O4/P–BiOBr nanocomposites substantially improved the synchronous decomposition of 4-CP and Cr(VI) compared to the single-phase component samples under visible light irradiation. Particularly, the 30-CoFe2O4/P–BiOBr nanocomposite displayed the best photocatalytic performance, which decomposed 95.6% 4-CP and 100% Cr(VI) within 75 min. The photocatalytic improvement was assigned to the Z-scheme heterojunction assisted charge migration between CoFe2O4 and P–BiOBr, and the acceleration of charge carrier separation was validated by the findings of charge dynamics measurements. The harmful 4-CP was photodegraded into smaller organics whereas the Cr(VI) was photoreduced into Cr(III) after 30-CoFe2O4/P–BiOBr photocatalysis, and the good recyclability of fabricated nanocomposite in photocatalytic reaction also showed promising potential for practical applications in environmental remediation. Finally, the radical quenching tests confirmed that there existed the Z-scheme path of charge migration in CoFe2O4/P–BiOBr nanocomposite, which was the mechanism responsible for its high photoactivity.
•Surfactant-free hydrothermal fabrication of novel Z-scheme CoFe2O4/P–BiOBr.•Effective 4-CP degradation and Cr(VI) reduction were synchronously obtained.•As-fabricated nanocomposite showed good reusability and easy magnetic separation.•Z-scheme ecb− migration improved charge separation and granted high redox ability.OH dominated 4-CP degradation while ecb− mainly responsible in Cr(VI) reduction.
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