Nanoscopic analysis of oxygen segregation at tilt boundaries in silicon ingots using atom probe tomography combined with TEM and ab initio calculations.

We have developed an analytical method to determine the segregation levels on the same tilt boundaries (TBs) at the same nanoscopic location by a joint use of atom probe tomography and scanning transmission electron microscopy, and discussed the mechanism of oxygen segregation at TBs in silicon ingots in terms of bond distortions around the TBs. The three-dimensional distribution of oxygen atoms was determined at the typical small- and large-angle TBs by atom probe tomography with a low impurity detection limit (0.01 at.% on a TB plane) simultaneously with high spatial resolution (about 0.4 nm). The three-dimensional distribution was correlated with the atomic stress around the TBs; the stress at large-angle TBs was estimated by ab initio calculations based on atomic resolution scanning transmission electron microscopy data and that at small-angle TBs were calculated with the elastic theory based on dark-field transmission electron microscopy data. Oxygen atoms would segregate at bond-centred sites under tensile stress above about 2 GPa, so as to attain a more stable bonding network by reducing the local stress. The number of oxygen atoms segregating in a unit TB area NGB (in atoms nm-2 ) was determined to be proportional to both the number of the atomic sites under tensile stress in a unit TB area nbc and the average concentration of oxygen atoms around the TB [Oi ] (in at.%) with NGB ∼ 50 nbc [Oi ].

(-)-Semivioxanthin, a new abscisic active compound against Hinoki cypress leaves isolated from Cryptosporiopsis abietina.

The new naphthopyrone, (-)-semivioxanthin (1) was isolated from Cryptosporiopsis abietina. The structure of 1 was determined as the reversed optical isomer of semivioxanthin by comparing its spectroscopic data with those of semivioxanthin. Compound 1 exhibited abscisic activity against Hinoki cypress leaves and antifungal activity against Cladosporium herbarum.

[Clinical evaluation of CA 19-9, TPA, IAP and 5'-NPD-V as tumor markers of hepatocellular, bile duct and pancreas carcinoma].

The serum level of CA 19-9 elevated exponentially in gastrointestinal carcinoma and the specificity of CA 19-9 was extraordinarily high. The sensitivity of CA 19-9 to pancreas, bile duct, hepatocellular and metastatic liver carcinoma was 75%, 79%, 22%, and 82% each. TPA seems to be useful as a screening tumor maker of gastrointestinal carcinoma, because the sensitivity was very high (84%) in every gastrointestinal carcinoma. IAP increased in pancreas and bile duct carcinoma and reflected immunological status of tumor bearing host. 5'-NPD-V was useful tumor marker not only of hepatocellular carcinoma but also pancreas and bile duct carcinoma.