A redox-mediator-free solar-driven Z-scheme water-splitting system consisting of modified Ta3N5 as an oxygen-evolution photocatalyst.

Tantalum nitride (Ta3N5) modified with various O2-evolution cocatalysts was employed as a photocatalyst for water oxidation under visible light (λ>420 nm) in an attempt to construct a redox-mediator-free Z-scheme water-splitting system. Ta3N5 was prepared by nitriding Ta2O5 powder under a flow of NH3 at 1023-1223 K. The activity of Ta3N5 for water oxidation from an aqueous AgNO3 solution as an electron acceptor without cocatalyst was dependent on the generation of a well-crystallized Ta3N5 phase with a low density of anionic defects.

Modified Ta3N5 powder as a photocatalyst for O2 evolution in a two-step water splitting system with an iodate/iodide shuttle redox mediator under visible light.

Modification of tantalum nitride (Ta(3)N(5)), which has a band gap of 2.1 eV, with nanoparticulate iridium (Ir) and rutile titania (R-TiO(2)) achieved functionality as an O(2) evolution photocatalyst in a two-step water-splitting system with an IO(3)(-)/I(-) shuttle redox mediator under visible light (lambda > 420 nm) in combination with a Pt/ZrO(2)/TaON H(2) evolution photocatalyst. The loaded Ir nanoparticles acted as active sites to reduce IO(3)(-) to I(-), while the R-TiO(2) modifier suppressed the adsorption of I(-) on Ta(3)N(5), allowing Ta(3)N(5) to evolve O(2) in the two-step water-splitting system.

Hydroxyapatite formed on/in agarose gel induces activation of blood coagulation and platelets aggregation.

We reported earlier that hydroxyapatite (HA) formed on/in agarose gels (HA/agarose) produced by alternate soaking process is a bone-filling material possessing osteoconductive and hemostatic effects. This process could allow us to make bone-like apatite that was formed on/in organic polymer hydrogel matrices. Here, we investigated the mechanism of hemostasis induced by HA/agarose and found that HA/agarose, but not agarose or HA powder, significantly shortened activated partial thromboplastin time (APTT).

Apatite formed on/in agarose gel as a bone-grafting material in the treatment of periodontal infrabony defect.

The present study was designed to evaluate the effects of a hydroxyapatite/agarose (HA/agarose) composite gel formed by a novel alternate soaking process for the treatment of periodontal infrabony defects in three dogs. After creating two-wall infrabony periodontal defects on the medial aspect of the maxillary and mandibular second and forth premolars, the defects were implanted with temporary dental filling material (stopping) to induce inflammatory periodontal disease. Two months later, the mucoperiosteal flaps were raised, and after debridement, the infrabony defects were filled with one of the following three materials: (a) HA/agarose, (b) Bone ject (True-Bone Ceramic-collagen combined bone graft material, Koken, Japan), or (c) no material implantation (negative control).

Osteoconductive and hemostatic properties of apatite formed on/in agarose gel as a bone-grafting material.

The biologic behavior of hydroxyapatite formed on/in agarose (HA/agarose) gels with the use of a novel alternate soaking process was compared with commercially available Bone Ject (True-Bone ceramic-collagen combined bone-graft material, Koken, Japan) as a filler for the tooth-extraction sockets of six adult monkeys (Macasa fascicularis). After the monkeys' first premolars were extracted, the defects created were replaced with one of the following materials: (a). HA/agarose created by 12 soaking cycles, (b).