Biomedical subjects

P Rudolf

Publications and source records attributed to P Rudolf.

18 recordsLinked to original sources

PubMed2005

The effect of oxygen exposure on pentacene electronic structure.

We use ultraviolet photoelectron spectroscopy to investigate the effect of oxygen and air exposure on the electronic structure of pentacene single crystals and thin films. It is found that O(2) and water do not react noticeably with pentacene, whereas singlet oxygen/ozone readily oxidize the organic compound. Also, we obtain no evidence for considerable p-type doping of pentacene by O(2) at low pressure. However, oxygen exposure lowers the hole injection barrier at the interface between Au and pentacene by 0.25 eV, presumably due to a modification of the Au surface properties.

Electrochemistry↗

PubMed2002

[Clinical significance of expression of the smooth muscle actin-alpha and CD34 antigen in mesangial cells in glomerulonephritis].

AIM: To assess clinical implications of expression of alpha-smooth-muscle actin (ASMA) and CD34 as markers of activation and transformation of mesangial cells. MATERIAL AND METHODS: ASMA and CD34 expression was investigated with indirect enzyme immunoassay with addition of the complex alkaline phosphatase-antiphosphatase, mean number of stained (expressing) mesangial cells per 1 glomerulus were estimated in 47 renal tissue biopsies from patients with different morphological types of glomerulonephritis and 9 biopsies of the kidneys removed for different tumors (control). RESULTS: Mean expression of ASMA (11.0 +/- 3.5) was significantly higher in GN proliferative types than in non-proliferative ones and controls. In patients with proliferative nephritis ASMA expression correlated with clinical signs of nephritis activity. CD34 was expressed similarly in patients with proliferative and non-proliferative nephritis and in controls. CD34 was higher in biopsies with higher degree of sclerosis in the kidney than in the biopsies with moderate sclerosis. CONCLUSION: ASMA and CD34 expression by mesangial cells in renal biopsies from GN patients can be used for evaluation of the disease activity and prognosis.

Actins↗

PubMed2000

Study of C60/Au(110)-p(6x5) reconstruction from In-plane X-Ray diffraction data

Fullerene molecules absorbed on the highly anisotropic Au(110)-p(1x2) surface induce an ordered p(6x5) superstructure that has been solved by applying the 2D "direct methods" difference sum function to the surface x-ray diffraction data set. We found that the C (60)-gold interface is structurally much more complex than the one previously suggested by scanning tunneling microscopy data [J. K. Gimzewski, S. Modesti, and R. R. Schlittler, Phys. Rev. Lett. 72, 1036 (1994)]. Indeed a large fraction of Au surface atoms are displaced from their original positions producing microscopic pits that may accommodate the fullerene molecules.

Journal Article↗

PubMed1995