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Biomedical subjects

H Brune

Publications and source records attributed to H Brune.

At least 19 recordsLinked to original sources
PubMed2000

Nature, strength, and consequences of indirect adsorbate interactions on metals

Atoms and molecules adsorbed on metals affect each other indirectly even over considerable distances. Via systematic density-functional calculations, we establish the nature and strength of such interactions, and explain for what adsorbate systems they critically affect important materials properties. This is verified in kinetic Monte Carlo simulations of epitaxial growth, which help rationalize a number of recent experimental reports on anomalously low diffusion prefactors.

Journal Article↗
PubMed1996

Controlled Deposition of Size-Selected Silver Nanoclusters

Variable-temperature scanning tunneling microscopy was used to study the effect of kinetic cluster energy and rare-gas buffer layers on the deposition process of size-selected silver nanoclusters on a platinum(111) surface. Clusters with impact energies of </=1 electron volt per atom could be landed nondestructively on the bare substrate, whereas at higher kinetic energies fragmentation and substrate damage were observed. Clusters with elevated impact energy could be soft-landed via an argon buffer layer on the platinum substrate, which efficiently dissipated the kinetic energy. Nondestructive cluster deposition represents a promising method to produce monodispersed nanostructures at surfaces.

Journal Article↗
PubMed1990

Evaluation of the carcinogenic potency of 4 environmental polycyclic aromatic compounds following intrapulmonary application in rats.

The carcinogenic potential of 4 highly purified polycyclic aromatic compounds (PAC) was studied in the respiratory tract of rats. Using a beeswax/trioctanoin mixture as vehicle, 10, 3 and 1 mg phenanthrene (PHE), 3 and 1 mg chrysene (CHR), 0.1 mg dibenz(a,h)anthracene (DBahA) and 6, 3 and 1 mg benzo(b)naphto(2,1-d)thiophene (BNT) were injected into the lungs of 35 female Osborne-Mendel rats per group. Benzo(a)pyrene (BaP, 0.3, 0.1 and 0.03 mg) was used as the reference substance. Whereas only one squamous cell carcinoma developed at the highest PHE dose, a dose-dependent tumor incidence was found for CHR. BNT showed a carcinogenic effect similar to CHR, but an increasing incidence of neoplasms was not seen between the median and high dose. DBahA induced carcinomas in even more than half of the animals at the dose level of 0.1 mg and, therefore, has to be classified as the most potent PAC under investigation. BaP resulted in a clear dose-response relationship. According to probit analysis of the results, the carcinogenic potencies of the PAC relative to BaP (1.00) rank as follows: DBahA, 1.91; CHR, 0.03; BNT, 0.02; and PHE, 0.001. The estimated ED10- values were 0.031 mg for BaP, 0.016 mg for DBahA, 1.02 mg for CHR, 1.65 mg for BNT and 22.84 mg for PHE.

Animals↗
PubMed1989

Urinary and faecal excretion of pyrene and hydroxypyrene by rats after oral, intraperitoneal, intratracheal or intrapulmonary application.

The urinary and faecal excretion of pyrene and 1-hydroxypyrene after oral (53.4%), intraperitoneal (3.1%), intratracheal (30-37%) and intrapulmonary application (0.003%) to rats has been determined by means of gas chromatography/mass spectrometry and the excretion rates were found to depend on the mode of application. With regard to the low urinary excretion rates, 1-hydroxypyrene seems not to be very suitable as a biological marker for PAH exposure to man.

Animals↗
PubMed1989

Dermal oncogenicity study of 2-ethylhexyl acrylate by epicutaneous application in male C3H/HeJ mice.

A carcinogenicity bioassay of 2-ethylhexyl acrylate (2-EHA) was conducted by applying 25 microliters 86.5%, 21%, or 2.5% 2-EHA in acetone three times a week to the clipped dorsal skin of male C3H/HeJ mice (80 per group) over their lifetime. Another group was treated with a 43% 2-EHA solution for 24 weeks and thereafter observed for lifetime (stop-test). An untreated group and a group that received only the diluent acetone served as controls. Treatment-related changes in the skin indicative of irritation (scaling, scabbing, hyperkeratosis, hyperplasia) were found in all 2-EHA-treated groups. These lesions were reversible in the 43% group immediately after treatment was stopped, and in the 2.5% group after the 11th week of treatment. Only in the 86.5% and 21% test groups showing chronic irritative skin damage was there a high incidence of nepolastic skin lesions (papillomas, carcinomas, and melanomas) with no dose dependency. In contrast, no skin tumors were found in the control groups, in the group treated with 2.5% 2-EHA for lifetime or in the group treated with 43% 2-EHA for about 6 months and observed for lifetime.

Acrylates↗