Green-and-Red Photoluminescence from Si-Si and Ge-Ge Bonded Network Homopolymers and Copolymers

Recently, we found pure green photoluminescence (PL) at 540 nm (2.34 eV) in a vacuum, which is characteristic of a Si-Si bonded network polymer bearing n-butyl groups (organopolysilyne, SNP). SNP was carefully isolated as an orange-yellow solid by avoidance of contact with air and water in the polymer synthesis and PL measurement. This was in contrast with previous reports that SNPs carrying alkyl groups have a blue PL band around 450-480 nm. By applying the modified technique to a soluble Ge-Ge bonded network polymer carrying n-butyl groups (organopolygermyne, GNP), with much care in synthesising the polymer and measuring the PL, we found that GNP reveals a very brilliant red-coloured PL band at 690 nm (1.80 eV) in a vacuum at 77 K. This was in contrast with a previous report that GNP carrying n-hexyl groups has a green PL band at 560 nm (2.21 eV). On the other hand, soluble Si-Ge network copolymers (SGNPs) prepared in a similar way to SNP and GNP syntheses showed green-and-red dual PL bands at 540 nm and 690 nm. Based on analyses with IR, Raman, HR-TEM, XPS, EELS, UV-Vis and PL data, the dual emission was assumed to originate from the coexistence of Si and Ge domains (1-2 nm in diameter), possibly, in the same skeleton of SGNP

Survey of the stray dog population and the health education program on the prevention of dog bites and dog-acquired infections: a comparative study in Nepal and Okayama Prefecture, Japan.

We estimated the number of stray dogs in Kathmandu, Nepal, where human rabies cases still occur, and in Shimotsui, Okayama Prefecture, Japan. In Kathmandu, the stray dog density was 2,930 stray dogs/km2, and the ratio of stray dogs to humans was 1:4.7. In Shimotsui, the density was 225 stray dogs/km2, and the ratio was 1:5.2. Since the stray dog population in Nepal is very large, one of the measures used to prevent dog bites and dog-acquired infections such as rabies is an effort to capture stray dogs. Another such measure is an effort to decrease the availability of food for stray dogs. We also organized health education programs in both Nepal and Okayama Prefecture, Japan, which involved a course on the prevention of dog bites and subsequent infections. After each course, a questionnaire survey was conducted. The results suggest that the course participants understood these important preventive methods. In addition to the measures mentioned above and the routine vaccination of dogs, this health education course is recommended as a long-term preventive program</p