Effect of B 2 O 3 content on crack resistance was investigated by indentation tests of glass samples with various compositions of B 2 O 3 . The ternary SiO 2 B 2 O 3 Na 2 O glass system (SBN series) and non-alkaline aluminoborosilicate glass system (SAB series). When B 2 O 3 is substituted with SiO 2 in the SBN system ("SBN1" series), crack resistance has a relationship with density. In a series of the SBN system where density did not change with B 2 O 3 content ("SBN2" series), crack resistance decreased with increasing B 2 O 3 content. On the other hand, crack resistance increased with increasing B 2 O 3 content in the SAB series, where density did not change. According to the results of NMR measurement, boron in 4-cordination state ([4] B) increased in the SBN2 series while boron in 3-cordination state ([3] B) increased in the SAB series with increasing B 2 O 3 content. Therefore, crack resistance increases with increasing [3] B and decreases with increasing[4] B. The difference in structure between [3] B and [4] B containing glasses leads to different effect on residual stress around the indentation, resulting in difference in crack resistance.

The shootin1–cortactin interaction participates in netrin-1–induced F-actin–adhesion coupling and in the promotion of traction forces for axon outgrowth.

No abstract

Recently, a cDNA from the hepatitis C virus (HCV) RNA genome has been isolated in the USA from a chronically infected chimpanzee. In order to isolate HCV cDNA derived from human material, RNA was extracted from plasma of a Japanese blood donor implicated in post-transfusion non-A, non-B hepatitis and HCV cDNA was synthesized and amplified by the PCR method using HCV-specific oligonucleotide primers. The cDNA fragment, 583 nucleotides long, showed 79.8% homology at the nucleotide level and 92.2% homology at the amino acid level compared with the prototype HCV cDNA. These results provides further evidence to show that HCV is closely associated with the development of post transfusion non-A, non-B hepatitis.

A sulfated polysaccharide named naviculan was isolated from a diatom, Navicula directa (W. SMITH) RALFS, collected in deep sea water from Toyama Bay. The polysaccharide consisted of fucose, xylose, galactose, mannose, rhamnose and sulfate with an apparent molecular weight of 220000. It showed antiviral activities against herpes simplex viruses type 1 and 2, and influenza A virus with selectivity indices (CC 50 /IC 50 ) of 270, 510 and 32, respectively. Naviculan also showed an inhibitory effect on cell-cell fusion between CD4-expressing and human immunodeficiency virus (HIV) gp160-expressing cells that was used as a model system of infection with HIV.