Efficient Mesh Interface Engineering: Insights from Bubble Dynamics in Electrocatalysis.

Electrochemical catalysis offers great potential in energy and mass conversion in academy and industry. However, bubble dynamics and its influence on gas-evolving electrode systems remain ambiguous. Detailed information on the local transport process between different phases and the underlying mechanism are required for the full understanding of two-phase flow evolution and distribution. Here, we construct a three-electrode water splitting reaction system to study the bubble dynamics and system efficiency of titanium electrodes with different morphologies. The dynamics of a gas bubble at an electrode with a plate and 100-mesh, 150-mesh, and 300-mesh structures is systematically investigated with respect to applied voltage conditions. Parameters and underlying mechanisms that influence the two-phase flow evolution and electrochemical reaction performance are carefully discussed. Finally, the underlying dynamic force balance on the gas bubble is analyzed to illustrate the mechanism and experimental observations. Our study provides insights in gas-evolving electrocatalysis and offers opportunities for the design and fabrication of high-performance electrocatalytic reactors.

Controllable Preparation of Ordered and Hierarchically Buckled Structures for Inflatable Tumor Ablation, Volumetric Strain Sensor, and Communication via Inflatable Antenna.

Inflatable conducting devices providing improved properties and functionalities are needed for diverse applications. However, the difficult part in making high-performance inflatable devices is the enabling of two-dimensional (2D) buckles with controlled structures on inflatable catheters. Here, we report the fabrication of highly inflatable devices with controllable structures by wrapping the super-aligned carbon nanotube sheet (SACNS) on the pre-inflated catheter. The resulting structure exhibits unique 2D buckled structures including quasi-parallel buckles, crisscrossed buckles, and hierarchically buckled structures, which enables reversible structural changes of 7470% volumetric strain. The 2D SACNS buckled structures show stable electrical conductance and surface wettability during large strain inflation/deflation cycles. Inflatable devices including inflatable tumor ablation, capacitive volumetric strain sensor, and communication via inflatable radio frequency antenna based on these structures are demonstrated.

Publisher Correction: Electric-field control of ferromagnetism through oxygen ion gating.

In the original version of this Article, Figs. 4c and 4d contained incorrectly sized error bars. This has now been corrected in both the PDF and HTML versions of the Article.

Electric-field control of ferromagnetism through oxygen ion gating.

Electric-field-driven oxygen ion evolution in the metal/oxide heterostructures emerges as an effective approach to achieve the electric-field control of ferromagnetism. However, the involved redox reaction of the metal layer typically requires extended operation time and elevated temperature condition, which greatly hinders its practical applications. Here, we achieve reversible sub-millisecond and room-temperature electric-field control of ferromagnetism in the Co layer of a Co/SrCoO2.5 system accompanied by bipolar resistance switching. In contrast to the previously reported redox reaction scenario, the oxygen ion evolution occurs only within the SrCoO2.5 layer, which serves as an oxygen ion gating layer, leading to modulation of the interfacial oxygen stoichiometry and magnetic state. This work identifies a simple and effective pathway to realize the electric-field control of ferromagnetism at room temperature, and may lead to applications that take advantage of both the resistance switching and magnetoelectric coupling.

(±)-Homocrepidine A, a Pair of Anti-inflammatory Enantiomeric Octahydroindolizine Alkaloid Dimers from Dendrobium crepidatum.

A pair of racemic indolizidine enantiomers, (±)-homocrepidine A (1), and a piperidine derivative, homocrepidine B (2), were isolated from Dendrobium crepidatum along with the known alkaloid crepidine (3). The racemic mixture of 1 was separated into a pair of enantiomers, (+)-1 and (-)-1, by HPLC using a chiral chromatographic substrate, which represents the first successful example of resolving indolizidine racemic mixtures. The absolute configurations of (+)-1 and (-)-1 were assigned from single-crystal X-ray diffraction data. The evaluation of anti-inflammatory activity with LPS-induced RAW 264.7 macrophages revealed that (+)-1 strongly inhibited the production of nitric oxide (IC50, 3.6 µM) and significantly decreased the expression of inducible nitric oxide synthase, while (-)-1 and (±)-1 only had moderate inhibitory effects (IC50, 22.8 and 14.7 µM). Compound 2 showed moderate anti-inflammatory activity (IC50, 27.6 µM).

A new triterpenoid bearing octacosanoate from the stems and roots of Clerodendrum philippinum var. simplex (Verbenaceae).

A new triterpenoid bearing octacosanoate, named taraxer-3ß-yl octacosanoate (1), together with 13 known compounds (2-14), was isolated from the ethanol extract of the stems and roots of Clerodendrum philippinum var. simplex. The structure of taraxer-3ß-yl octacosanoate (1) was elucidated by extensive spectroscopic analysis. Uncinatone (8) and clerodenone A (10) exhibited inhibition of lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophages with IC50 values of 12.50 and 3.18 µM, respectively.

Uncarilic acid and secouncarilic acid, two new triterpenoids from Uucaria sessilifructus.

Two new compounds, the 6-oxo oleanane-type triterpenoid uncarilic acid, and its 5,6-secotriterpenoid derivative, secouncarilic acid, were isolated from the hooks and stems of Uucaria sessilifructus together with seven known ursane-type triterpenoids. Uncarilic acid is the second 6-oxo oleanane-type triterpenoid ever reported, while secouncarilic acid is the first oleanane-type 5,6-secotriterpenoid. A plausible biosynthetic pathway from uncarilic acid to secouncarilic acid was also postulated. The inhibitory activities of all the nine compounds against LPS-induced nitric oxide production in RAW264.7 macrophages were evaluated.