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Nickel, cadmium, cobalt, and arsenic compounds are well-known carcinogens to humans and experimental animals. Even though their DNA-damaging potentials are rather weak, they interfere with the nucleotide and base excision repair at low, noncytotoxic concentrations. For example, both water-soluble Ni(II) and particulate black NiO greatly reduced the repair of DNA adducts induced by benzo[a]pyrene, an important environmental pollutant. Furthermore, Ni(II), As(III), and Co(II) interfered with cell cycle progression and cell cycle control in response to ultraviolet C radiation. As potential molecular targets, interactions with so-called zinc finger proteins involved in DNA repair and/or DNA damage signaling were investigated. We observed an inactivation of the bacterial formamidopyrimidine-DNA glycosylase (Fpg), the mammalian xeroderma pigmentosum group A protein (XPA), and the poly(adenosine diphosphate-ribose)polymerase (PARP). Although all proteins were inhibited by Cd(II) and Cu(II), XPA and PARP but not Fpg were inhibited by Co(II) and Ni(II). As(III) deserves special attention, as it inactivated only PARP, but did so at very low concentrations starting from 10 nM. Because DNA is permanently damaged by endogenous and environmental factors, functioning processing of DNA lesions is an important prerequisite for maintaining genomic integrity; its inactivation by metal compounds may therefore constitute an important mechanism of metal-related carcinogenicity.

The need for accurate, non-invasive methods to monitor reactor kinetics motivated SANDcaStLE (Simultaneous Analysis of Noise Detectors and Spectroscopy of a Low-power Experiment) at the CROCUS zero-power reactor. This study compares various neutron and gamma-ray detection systems, including fission chambers, a novel 3D neutron detection array called SAFFRON, and inorganic scintillators, to estimate the prompt neutron decay constant ( α ) from the fission “noise” at 8.92 mW critical. Our results show that gamma-ray measurements are highly effective, achieving a relative uncertainty of less than 15% in just one minute, an improvement over the three minutes required by ex-core fission chambers. Additionally, the SAFFRON array could detect fission noise despite its low total efficiency. The SAFFRON array was distributed through the radius and height of the core, suggesting the importance of detector spatial distribution in noise analysis. The fission chamber and inorganic scintillator systems agreed with the Serpent 2 IFP simulation α within 10 minutes of measurement time.