Controlling the Release of Hydrogen Peroxide from Catechol-Based Adhesive Using Silica Nanoparticle.

Catechol-based bioadhesives generate hydrogen peroxide (H2O2) as a byproduct during the curing process. H2O2 can have both beneficial and deleterious effects on biological systems depending on its concentration. To control the amount of H2O2 released from catechol-containing polyethylene glycol-based adhesive (PEG-DA), adhesive was formulated with silica nanoparticles (SiNP) prepared with increased porosity and acid treatment to increase Si-OH surface content. These SiNP demonstrated increased surface area, which promoted interaction with catechol and resulted in increased cure rate, bulk mechanical properties and adhesive properties of PEG-DA. Most importantly, SiNP demonstrated a 50% reduction in the released H2O2 while improving the cell viability and proliferation of three primary cell types, including rat dermal fibroblasts, human epidermal keratinocytes, and human tenocytes. Additionally, SiNP degraded into soluble Si, which also contributed to increased cell proliferation. Incorporation of porous and acid-treated SiNP can be a useful approach to simultaneously modulate the concentration of H2O2 while increasing the adhesive performance of catechol-based adhesives.

3D Channel-structured graphene as efficient electrodes for capacitive deionization.

Capacitive deionization (CDI), which is one of up-and-coming water treatment technologies, is based on ion electrostatic adsorption on electrode surface. Herein, three-dimensional channel-structured graphene (CSG), which was synthesized via exothermic reaction between liquid potassium and carbon monoxide gas, was demonstrated as an efficient electrode material for CDI. Namely, the CSG electrode exhibited a specific capacity of 207.4 F/g at 0.2 A/g in 1 M NaCl aqueous solution. In a batch-mode recycling system, the electrosorption capacity of CSG can achieve 5.70 and 9.60 mg/g at 1.5 V in 50 and 295 mg/l NaCl aqueous solutions, respectively. The excellent electrosorption capacity of CSG, especially under low saline concentration, can be attributed to the synergistic effect of its large surface area (711.9 m2/g), unique channel structure, and oxygen functional groups.

Investigation on H-containing shallow trap of hydrogenated TiO2 with in situ Fourier transform infrared diffuse reflection spectroscopy.

A novel technique, high temperature high pressure in situ Fourier transform infrared diffuse reflection spectroscopy, was successfully used to investigate the formation and stability of shallow trap states in P25 TiO2 nanoparticles. Two types of shallow traps (with and without H atoms) were identified. The H-containing shallow trap can be easily generated by heating in H2 atmosphere. However, the trap is unstable in vacuum at 600 °C. In contrast, the H-free shallow trap, which can be formed by heating in vacuum, is stable even at 600 °C. The energy gaps between shallow trap states and the conduction band are 0.09 eV for H-containing shallow trap and 0.13 eV for H-free shallow trap, indicating that the H-containing shallow trap state is closer to the conduction band than that without H.

Quantum chemical density-functional theory calculations of the structures of defect C60 with four vacancies.

Quantum chemical density-functional theory (DFT) calculations have been carried out for the six isomers obtained by removing four adjacent atoms from C60. The most stable isomer consists of twelve 5-member and eighteen 6-member rings, indicating that the removal of some atoms from C60, which contains twelve 5-member rings and twenty 6-member rings, does not always generate larger holes. Each of the other five isomers contains at least one 4-member ring and one larger ring (7-, 8-, 9-, or 10-member ring) besides the 5- and 6-member rings. All isomers have similar structures for singlet and triplet spin multiplicities but with different stabilities. The ground states for two of the isomers are triplets, whereas the ground states for the other isomers are singlets. Furthermore, a comparison between the various isomers allowed one to examine the effect of the structure on the stability of fullerene cages.