The pesticides have different adverse impacts on different life stages of fish species with attempts to
use dietary antioxidants to counteract their effects. So, the present study investigated the potential
protective effects of vitamin E (50 mg/kg BW), tomato paste (in terms of 9 mg lycopene/kg BW) and their
combination versus atrazine-induced changes in Clarias gariepinus. This species were exposed to
sublethal doses of atrazine of 1.7 and 3.4 mg/L for 15 and 30 days. Atrazine significantly (P<0.05)
induced free radicals in serum constituents. It caused a significant (P<0.05) increase in serum glucose,
mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and lipid peroxidation in liver.
Addition of vitamin E and/or tomato paste to the diet of atrazine-treated fish improved the serum
glucose, MCV, MCH and LPO levels in comparison to control fish. On the other hand, atrazine
significantly (P<0.05) led to decline in serum total protein, total lipid, blood hemoglobin, total
erythrocytes count, packed cell volume, and mean corpuscular hemoglobin concentration.These
atrazine-induced parameters were improved with the dietary supplemented tomato paste and/or vitamin
E.

The reaction mechanisms for the reactions of cobaltacyclopentadiene with isocyanate and isothiocyanate
exclusively in singlet or triplet states, or involving transition between states, were studied by means of
hybrid density functional theory (B3LYP) calculations. The results clearly showed that a two-state
mechanism involving both singlet and triplet states is more favorable than the corresponding singlestate
mechanism for all the reactions. We also found that the reactions of isocyanate and isothiocyanate
to give pyridin-2(1H)-one and pyridine-2(1H)-thione complexes, respectively, are more favorable
than those that give 2H-pyran-2-imine and 2H-thiopyran-2-imine complexes. This is mainly due to the
greater stabilities of pyridin-2(1H)-one and pyridine-2(1H)-thione compared with 2H-pyran-2-imine
and 2H-thiopyran-2-imine. A change in spin state plays a crucial role in the two-state mechanism;
first, the C]N bond of the isocyanate or isothiocyanate inserts into the CoeCa bond of cobaltacyclopentadiene
in the singlet state to give azacobaltacycloheptadienone or azacobaltacycloheptadienethione
intermediates, and subsequent reductive elimination in the triplet state gives the pyridin-2(1H)-one or
pyridine-2(1H)-thione complex, respectively.