Magnetic-field dependence of tunnel couplings in carbon nanotube quantum dots.

By means of sequential and cotunneling spectroscopy, we study the tunnel couplings between metallic leads and individual levels in a carbon nanotube quantum dot. The levels are ordered in shells consisting of two doublets with strong- and weak-tunnel couplings, leading to gate-dependent level renormalization. By comparison to a one- and two-shell model, this is shown to be a consequence of disorder-induced valley mixing in the nanotube. Moreover, a parallel magnetic field is shown to reduce this mixing and thus suppress the effects of tunnel renormalization.

[Modification of the genetic effect of radiation in mice exposed in the region of the Chernobyl Atomic Electric Power Station]. / Modifikatsiia geneticheskogo éffekta radiatsii u myshei, éksponirovannykh v raione Chernobyl'skoi AES.

A study was made of the protective effect of beta-carotine and ephasol against genetic damages in germ cells of male mice, exposed within the zone of Chernobyl NPP or ingested by 137Cs. The analysis of reproductive function, frequencies of dominant lethal mutations, abnormal sperm heads, reciprocal translocations and testis mass decrease show that both agents are more effective in protection against reproductive function damages than against genetic effects.

[The radioprotective action of efazol under different conditions of irradiation of the germ cells of male mice]. / Radiozashchitnoe deistvie éfazola pri raznykh usloviiakh oblucheniia polovykh samtsov myshei.

A study was made of the protective effect of ephasol against genetic damages induced in mice germ cells by single, fractionated and chronic gamma radiation. Study of male reproductive ability, frequency of induced dominant lethal mutations, abnormal sperm heads and reciprocal translocation show that the efficacy of ephasol was higher in condition of chronic exposure.