Sodium ion batteries (SIBs) are emerging as one of the most promising candidates for large-scale energy storage due to the abundance of sodium. Layered manganese-based oxides, owing to relatively high capacity and low cost, exhibit great potential as SIBs cathode materials, but the cycling life remains a big challenge towards practical applications. Herein, unprecedented electrochemical performance is achieved in P2-type layered Na 2/3 Ni 1/3 Mn 2/3 O 2 cathode, and new insights into understanding the structure-performance correlation are gained. Na 2/3 Ni 1/3 Mn 2/3 O 2 delivers outstanding cycling stability (~ 80% capacity retention for 2000 cycles, 0.01% capacity loss per cycle),excellent rate capability (70.21% capacity retention at 20 C compared to 0.1 C), and a useable reversible capacity of about 84 mAh g -1 through tailoring its operating voltage range of 2.0–4.0 V. Moreover, the crystal structure of Na 2/3 Ni 1/3 Mn 2/3 O 2 is investigated in depth at atomic resolution, and sodium atoms located at 2d Wyckoff sites in different layers are clearly observed and directly distinguished for the first time. Both in-situ X-ray diffraction (XRD) and ex-situ high-resolution transmission electron microscopy (HRTEM) results reveal that the exceptional electrochemical performance is mainly attributed to the superior structural stability of Na 2/3 Ni 1/3 Mn 2/3 O 2 during the Na + insertion/extraction process. The present results suggest that P2-type Na 2/3 Ni 1/3 Mn 2/3 O 2 is an extremely promising cathode material for advanced long-life SIBs towards grid storage application.
As one promising candidate for next-generation energy storage systems, K-ion batteries (KIBs) attract increasing research attention due to the element abundance, low cost, and competent energy density as compared to Li-ion batteries. However, developing practical electrode materials in particular cathodes for KIBs is still in its infancy, and the related reaction mechanisms of the electrode materials are far from completely understood. In this work, TiSe2 was, for the first time, investigated as an intercalated-type electrode for potassium storage due to its large interlayer space. The potassiation/depotassiation reaction mechanism was unraveled based on the analysis of in-situ X-ray diffraction (XRD), ex-situ X-ray photoelectron spectroscopy (XPS), and ex-situ transmission electron microscope (TEM) results. Meanwhile, the lithium storage behaviour and the relevant lithiation/delithiation reaction mechanism were also studied in detail. The results reveal that K+ show lower diffusion coefficient and hence more sluggish intercalation reaction kinetics as compared with Li+. In addition, the intercalation reaction of K+ would cause irreversible structure changes, while the intercalation reaction is fully reversible for Li+ counterpart.
Numerical simulation is carried out to study the phenomenon of vortexbreakdown in an enclosed cylinder. The energy gradient theory is used toexplain the vortex breakdown in the cylinder with consideration of centrifugalforce, Coriolis force, angular momentum and azimuthal vorticity. The researchresults show that the large value of energy gradient function K is mainlylocated at the centerline and the region between the circulation vortices onboth sides of the cylinder and the vortex breakdown bubbles at the centerline.It is found that the position of the local peak value of the energy gradientfunction K at the centerline corresponds to the location of vortex breakdownfirst occurrence. The position of the local peak value of K function inhorizontal direction corresponds to the velocity inflection points except forthe centerline. The vortex breakdown is mainly determined by the high K valueat the centerline for low aspect ratio. The influence of the region of high Kvalue between the circulation vortices on both sides of the cylinder and thevortex breakdown bubbles at the centerline becomes larger with the increase ofthe aspect ratio. The occurrence and development of the vortex breakdown bubblemay be affected by the region of high K value between the circulation vorticeson both sides of the cylinder and the vortex breakdown bubbles at thecenterline for high aspect ratio.
Hematopoietic stem cells (HSCs) are multipotent cells responsible for the maintenance of the hematopoietic system throughout life. Dysregulation of the balance in HSC self-renewal, death, and differentiation can have serious consequences such as myelodysplastic syndromes or leukemia. All-trans retinoic acid (ATRA), the biologically active metabolite of vitamin A/RA, has been shown to have pleiotropic effects on hematopoietic cells, enhancing HSC self-renewal while also increasing differentiation of more mature progenitors. Furthermore, ATRA has been shown to have key roles in regulating the specification and formation of hematopoietic cells from pluripotent stem cells including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). Here, we summarize the known roles of vitamin A and RA receptors in the regulation of hematopoiesis from HSCs, ES, and iPSCs.
H2S and HCl are common impurities in raw syngas produced during gasification of biomass and municipal solid waste. The purpose of this study was to investigate the poisoning effect of H2S and HCl on synthesized and commercial catalysts during steam reforming of naphthalene. Four synthesized catalysts with different loadings of Ni and Fe on alumina support and two commercial catalysts were selected and evaluated in a fixed bed reactor at 790, 850 and 900 °C. The obtained results revealed that reforming and water-gas shift (WGS) activities of catalysts did not benefit from the Fe addition. The activities were influenced differently by H2S and HCl indicating that the reactions were catalyzed by different active sites on the nickel surface. In the presence of H2S and HCl, the poisoning of naphthalene reforming activity was caused by H2S and was not affected by HCl when both compounds were present in the gas. H2S chemisorbs on nickel surface forming NiS and decreasing the accessibility of active sites to hydrocarbons. The poisoning effect was only partially reversible. On the contrary, the poisoning of WGS activity could be caused by both H2S and HCl, and the activity could be completely restored when H2S and HCl were removed from the gas. Unlike naphthalene reforming activity, which was comparable for catalysts with similar Ni loadings, WGS activity depended on the catalyst structure and was less susceptible to poisoning by H2S and HCl in case of the catalyst with strong NiO-support interactions.
Cannabinoid receptor 2 (CB2R) is a therapeutic target in inflammatory diseases; its activation by agonists provides important clinical information, but there are currently no methods to quantify CB2R activation in humans. Chinese hamster ovary (CHO)-K1 cells and mouse and human whole blood cells were used for experiments. CB2R was activated in cells by treatment with the agonist CP55,940. Cells were also pretreated with proprietary Compound A and B (experimental agonists). We developed our method based on the finding that CB2R ligand binding and activation stimulates acute-phase extracellular signal-regulated kinase (ERK) phosphorylation in human and rodent immune cells, after which CB2R becomes unresponsive to stimulation by a second CB2R agonist CP55940 for a certain time period. We detected ERK phosphorylation as a measure of target engagement in mouse and human whole blood cells by flow cytometry. In cells overexpressing human or mouse CB2R, pretreatment with Compound A dose-dependently inhibited ERK phosphorylation for 2 h, prolonging the time window for measuring ERK phosphorylation. Our method enables measurement of CB2R activation by its agonists in human blood cells based on detection of ERK phosphorylation, which is useful for therapeutic drug monitoring and other clinical applications.