A photomask blank for producing a photomask to which an ArF excimer laser light is applied. The mixed metal borohydrides are synthesized through solution synthesis using multiple metal borohydrides. The connection may splice together two individual cables, or a cable to an electrical element. The open end is adapted to receive the dental implant. , to get the porous noble metal oxide nanoparticles; porous noble metal oxide nanoparticles obtained thereby and their use.