First principles based proximity effect of superconductor–normal metal heterostructures

In this paper we study the proximity effect in superconductor-normal metal heterostructures based on first principles calculations with treating the pairing potential as an adjustable parameter. The superconducting order parameter (anomalous density) is obtained from the Green-function by solving the Kohn-Sham-Bogoliubov-de Gennes equations with the Screened Korringa-Kohn-Rostoker method. The results are interpreted for an Au/Nb(0 0 1) system. The layer resolved anomalous spectral function is also obtained which is closely related to the superconducting order parameter. We find that the anomalous spectral function has the fingerprint of the Andreev scattering process and it is connected to the electron-hole ratio of the quasiparticle states. We also show that the proximity effect can be understood via the anomalous spectral function.</p

Endotoxins do not influence transplacental transmission of lymphotropic human herpesviruses and human papillomaviruses into amniotic fluid taken from healthy mothers before parturition in Hungary

Pregnant women were examined following healthy pregnancies at term. Amniotic fluids were sampled before arteficial rupture of membranes using closed vacutainer system. Blood samples were also taken from the pregnants simultaneously. Endotoxin concentrations of amniotic fluids were tested by the semiquantitative Limulus amebocyte lysate. Both amniotic fluids and blood samples were tested for the presence of DNA of lymphotropic human herpesviruses. The DNA of human papillomaviruses were tested only in the amniotic fluid samples. One-third of the amniotic fluids tested were found to contain measurable amounts of endotoxin. Lymphotropic herpesvirus DNA was deteced in every fourth amniotic fluid sample and in every 8th blood sample. The prevalence of papillomaviruses was 7 of 96 samples. No significant correlation was found between the presence of endotoxin and viruses in the amniotic fluids. Epstein-Barr virus, human cytomegalovirus and human herpesvirus type 7 were found more frequently in the amniotic fluids than in blood samples (7 to 1). The prevalence of human herpesvirus 6 and 8 was higher in the blood samples than that in the amniotic fluids. The mean weight of the neonates were not impaired significantly by the presence of either viruses or endotoxin. Possible post partum consequences, i.e. partial immunotolerance to viruses is discussed