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Polyamines are important polycations that play critical roles in mammalian cells. ATP13A2 belongs to the orphan P5B adenosine triphosphatases (ATPase) family and has been established as a lysosomal polyamine exporter to maintain the normal function of lysosomes and mitochondria. Previous studies have reported that several human neurodegenerative disorders are related to mutations in the ATP13A2 gene. However, the transport mechanism of ATP13A2 in the lysosome remains unclear. Here, we report the cryo-electron microscopy (cryo-EM) structures of three distinct intermediates of the human ATP13A2, revealing key insights into the spermine (SPM) transport cycle in the lysosome. The transmembrane domain serves as a substrate binding site and the C-terminal domain is essential for protein stability and may play a regulatory role. These findings advance our understanding of the polyamine transport mechanism, the lipid-associated regulation, and the disease-associated mutants of ATP13A2.

Computer simulations were performed on the spontaneous solidification and artificial intervention solidification processes of liquid gallium (Ga) by using molecular dynamics. The formation and evolution mechanism of the microstructure of liquid Ga under different solidification conditions were systematically studied using a combination of microstructural methods including the pair distribution function, bond-type index, and cluster-type index. The simulation results revealed that spontaneous homogeneous nucleation started from icosahedrons and defective icosahedrons. Artificial intervention can effectively control the thermostatic crystallization processes of liquid Ga, favoring crystal formation with large grains. The simulation results explain important experimental phenomena and the solidification theory of Ga smelting by the crystallization method from the microscopical point of view. We tested experimentally the process conditions for high-purity Ga smelting by the crystallization method as obtained from our simulations, resulting in successful preparation of metallic Ga with purity of 99.99999%.

In this study, poly-toluene isomers, such as poly(o-toluidine), poly(m-toluidine), and poly(p-toluidine), (abbreviated as POT, PMT, and PPT, respectively), were investigated for the corrosion protection of mild steel in 3.5% NaCl. The polymers were prepared by chemical oxidation and characterized by Fourier-transform infrared spectroscopy, UV–visible spectroscopy, x-ray diffraction, cyclic voltammetry, and scanning electron microscopy. The corrosion inhibition abilities of these coatings were evaluated by polarization and electrochemical impedance spectroscopy in aqueous NaCl solution. The results of this study showed that the inhibition efficiency of PMT reached 82.1%, which was greater than those of POT and PPT with 74.5% and 69.2%, respectively. In addition, the corresponding corrosion rates of PMT, POT, and PPT are 1.3 × 10−4 mm/year, 1.0 × 10−3 mm/year, and 4.1 × 10−2 mm/year, respectively. All these data reveal excellent properties of PMT in terms of corrosion protection.

Anatase TiO2 nanospheres (ATNSs) were successfully prepared through a facile solvothermal method followed by a thermal treatment. The sample was characterized by scanning electrons microscopy, transmission electron microscopy, x-ray diffraction, Raman spectrum and nitrogen adsorption techniques. When tested as an anode material for sodium-ion batteries, the electrode of ATNSs delivered a large discharge capacity of 208 mAh g−1 after 100 cycles at a current density of 50 mA g−1, indicating excellent cycling performance. This could be attributed to the uniform structure of the nanospheres with large surface area and porous nature, providing more active sites, buffering volume change, and facilitating the sodium ion intercalation as well as rapid diffusion during the charge/discharge process. Cyclic voltammetry demonstrated that the sodium storage mechanism is mainly controlled by pseudocapacitive behavior, resulting in a large capacity and outstanding cycling stability.

Porous hard carbon with large interlayer distance was fabricated from walnut shells through a facile high-temperature pyrolysis process and investigated as an anode material for sodium-ion batteries (SIBs). The results show that the electrochemical performance is mainly dependent on the pyrolysis temperature. The porous hard carbon, which was carbonized at 1300°C, displays the highest reversible capacity of 230 mAh g−1 at 20 mA g−1 and an excellent cycling stability (96% capacity retained over 200 cycles). The promising electrochemical performances are attributed to the porous structure reducing distances for sodium ion diffusion and expanded interlayer spacing, which is beneficial for sodium reversible insertion/extraction. The excellent electrochemical performance as well as the low-cost and environmental friendliness demonstrates that walnut shell-derived porous hard carbon is a promising anode material candidate for SIBs.