The intensity of mitogenetic radiation was estimated from data given by Gurwitsch. The sensitivity of the biological method and of the physical methods were compared. With onion-base pulp and onion roots as mitogenetic inductors, the photographic method gave no perceptible blackening for exposures up to 184 hours. A photoelectric counter tube was described with cadmium as photoelectric metal. Its sensitivity was such that a radiation intensity of 10 to 15 quanta per cm.(2) per second of the Hg line 2536 A was detectable. Spurious effects produced by the counter tube were described and means for their avoidance given. A number of different biological materials, all supposed to be excellent mitogenetic radiators, were investigated by means of the counter tube. No mitogenetic radiation could be detected.

Freezing-thawing cycles often occurs in the regions of mid-high latitude and high altitude. This process can affect soil physical and biological properties, e.g., soil water status, aggregate stability, and microbial biomass and community structure. Under its effects, the bio-indicators of soil microbes, i.e., the kinds and quantities of some specific amino sugars varied, and the course and intensity of soil nitrogen transformation changed, which resulted in an increase of nitrous oxide (N2O) production and emission, and made the soil be a major source of N2O emission. This paper summarized the research progress on the aspects mentioned above, with the further research directions on the theoretical problems of soil N2O production and emission under effects of freezing-thawing suggested.

Atomic emission multichannel special device involves sensitive methods to determine levels of cadmium, copper, lead and zinc in human serum, of cobalt, manganese, copper and nickel in human urine. Those methods could be applied in laboratories providing toxicologic and hygienic research.

The iron-chelator desferrioxamine (DFO) and the transition metal cobalt induce hypoxia-inducible factor-1alpha (HIF-1alpha) in normoxia. DFO stabilizes HIF-1alpha from proteolysis by inhibiting the activity of iron-dependent prolyl hydroxylases, but the mechanism of action of cobalt is not fully elucidated. The purpose of this study was to examine the regulation of HIF-1alpha induction and HeLa cell proliferation by cobalt and the role of iron in these processes. Our results show that, unlike DFO, induction of transcriptionally active HIF-1alpha by CoCl2 cannot be abrogated by the addition of excess Fe3+, but involves the production of reactive oxygen species (ROS) and the operation of the phosphatidylinositol-3 kinase (PI-3K) and MAPK pathways. CoCl2, as well as DFO, decreased HeLa cell proliferation, but these effects were reversed by the addition of Fe3+. We conclude that the effect of cobalt on cell proliferation is iron-dependent, while its effects on HIF-1alpha induction are ROS- and signaling pathways-dependent, but iron-independent.

Since in nuclear power plants, risks of skin contact contamination by radiocobalt are significant, we focused on the impact of cobalt on a human cutaneous cell line, i.e. HaCaT keratinocytes. The present paper reports an interdisciplinary approach aimed at clarifying the biochemical mechanisms of metabolism and toxicity of cobalt in HaCaT cells. Firstly, a brief overview of the used instrumental techniques is reported. The following parts present description and discussion of results concerning:(i) toxicological studies concerning cobalt impact towards HaCaT cells (ii) structural and speciation fundamental studies of cobalt-bioligand systems, through X-ray absorption spectroscopy (XAS), ab initio and thermodynamic modelling (iii) preliminary results regarding intracellular cobalt speciation in HaCaT cells using size exclusion chromatography/inductively coupled plasma-atomic emission spectroscopy (SEC/ICP-AES) and direct in situ analysis by ion beam micropobe analytical techniques.