The development of new materials/structures for efficient electrocatalytic water oxidation, which is a key reaction in realizing artificial photosynthesis, is an ongoing challenge. Herein, a Co(OH)F material as a new electrocatalyst for the oxygen evolution reaction (OER) is reported. The as-prepared 3D Co(OH)F microspheres are built by 2D nanoflake building blocks, which are further woven by 1D nanorod foundations. Weaving and building the substructures (1D nanorods and 2D nanoflakes) provides high structural void porosity with sufficient interior space in the resulting 3D material. The hierarchical structure of this Co(OH)F material combines the merits of all material dimensions in heterogeneous catalysis. The anisotropic low-dimensional (1D and 2D) substructures possess the advantages of a high surface-to-volume ratio and fast charge transport. The interconnectivity of the nanorods is also beneficial for charge transport. The high-dimensional (3D) architecture results in sufficient active sites per the projected electrode surface area and is favorable for efficient mass diffusion during catalysis. A low overpotential of 313 mV is required to drive an OER current density of 10 mA cm on a simple glassy carbon (GC) working electrode in a 1.0 m KOH aqueous solution.

Lithium niobate (LN) microdisk resonators on a LN-silica-LN chip were fabricated using only conventional semiconductor fabrication processes. The quality factor of the LN resonator with a 39.6-μm radius and a 0.5-μm thickness is up to 1.19 × 10(6), which doubles the record of the quality factor 4.84 × 10(5) of LN resonators produced by microfabrication methods allowing batch production. Electro-optic modulation with an effective resonance-frequency tuning rate of 3.0 GHz/V was demonstrated in the fabricated LN microdisk resonator.

Polyphosphate inorganic polymer is evaluated as a high‐performance lubricant for steel/steel contacts at 600, 700, and 800 °C. In situ thermal tests of this lubricant indicate that liquid lubrication at the rubbing interface is occurring. Tribological testing indicates the molten polyphosphate is effective as a lubricant and, reduces friction and wear of the sliding steel/steel tribo pair substantially. The lubricated steel/steel pair shows desirable tribological performance that correlates closely with the temperature‐dependent hierarchical structure of the tribo‐interface under the combination of pressure, shear, and temperature. Morphological observation of worn surfaces and interfaces of steel discs is achieved using scanning electron microscopy and transmission electron microscopy (TEM). Compositional analysis and elemental distribution are performed using X‐ray photoelectron spectroscopy and energy dispersive X‐ray on a scanning TEM. These enable the tribochemical reactions at the rubbing surface and the formation mechanism of the hierarchical tribo‐interface to be understood.

The protein kinase Chk1 is essential for the DNA damage checkpoint. Cells lacking Chk1 are hypersensitive to DNA-damaging agents such as UV light and gamma-irradiation because they fail to arrest the cell cycle when DNA damage is generated. Phosphorylation of Chk1 occurs after DNA damage and is dependent on the integrity of the DNA damage checkpoint pathway. We have tested whether a topoisomerase I inhibitor, camptothecin (CPT), generates DNA damage in the fission yeast Schizosaccharomyces pombe that results in Chk1 phosphorylation. We demonstrate that Chk1 is phosphorylated in response to CPT treatment in a time- and dose-dependent manner and that phosphorylation is dependent on an intact DNA damage checkpoint pathway. Furthermore, we show that cells must be actively dividing in order for CPT to generate a Chk1-responsive DNA damage signal. This observation is consistent with a model whereby the cytotoxic event caused by CPT treatment is the production of a DNA double-strand break resulting from the collision of a DNA replication fork with a trapped CPT-topoisomerase I cleavable complex. Cells lacking Chk1 are hypersensitive to CPT treatment, suggesting that the DNA damage checkpoint pathway can be an important determinant for CPT sensitivity or resistance. Finally, as a well-characterized, soluble agent that specifically causes DNA damage, CPT will allow a biochemical analysis of the checkpoint pathway that responds to DNA damage.

No abstract