Double-hybrid density functional theory for g-tensor calculations using gauge including atomic orbitals.

An efficient implementation for calculations of the electronic g-tensor at the level of second-order Møller-Plesset perturbation theory (MP2) is presented. The resolution of identity (RI) approximation is applied for the efficient treatment of two-electron integrals, and gauge including atomic orbitals are used to circumvent the gauge problem present in all magnetic property calculations. Furthermore, given that MP2 is an ingredient in double-hybrid density functional theory (DHDFT), the latter is also featured in the implementation. Calculated g-shifts with RI-MP2 and DHDFT using the double-hybrid density functionals B2PLYP and DSD-PBEP86 are compared to experimental data and published data from other methods including coupled cluster singles doubles. Additionally, the computational performance for medium to large size molecular systems was studied using the RIJK and RIJCOSX approximations for the two-electron integral treatment in the formation of Fock and Fock-like matrices necessary for the calculation of analytic second derivatives.

Radioprotectant Activity of Dicopper(II) Tetrakis(3,5- Diisopropylsalicylate) and Manganese(II) bis(3,5- Diisopropylsalicylate) Alone and in Combination.

Dicopper(ll) tetrakis(3,5-diisopropylsalicylate), (Cu(II)(2)(3,5-DIPS)(4), manganese(II) bis(3,5-diisopropylsalicylate), Mn(II)3,5-DIPS)(2) or combinations of them were used to treat gamma-irradIated mice in examining the possibility that combination treatments might be more effective in increasing survival than treatment with either complex alone. Doses of 0, 10, 20, or 40 mumol of each complex per kilogram of body mass were administered subcutaneously in a factorial design before 9 Gy gamna irradiation, an LD(90) dose of irradiation. Doses of 0, 10, 20, or 40 mumol Cu(II)(2)(3, 5-DIPS)(4) per kg of body mass produced 12, 28, 28, or 36 % survival, respectively, while doses of 0, 10, 20, or 40 mumol (II)(3), 5-DIPS)(2) per kg of body mass prduced 12, 36, 20, or 24 % survival, respectively. However, the combination of 20 mumol Cu(II)(2)(3, 5-DIPS)(4) and 10 mumol Mn(II)(3, 5-DIPS)(2) produced the greatest survival, 48 %, which was 300 % greater than vehicle-treated mice (P=0.01). It is concluded that specific combination treatments can be used to maximize survival of lethally irradiated mice.

Radioprotectant Activity of 5-Diethylsulfonamoylsalicylatocopper(II) in Gamma Irradiated Mice.

Survival and changes in mean body mass of whole-body irradiated mice were determined to examine the radioprotectant activity of 5-diethylsulfonamoylsalicylatocopper(II) [Cu(II) (5-DESS)]. One of four groups of 25 female C57BL/6 mice were treated subcutaneously (sc)with 0, 10, 20, 40, 60, 80, 100, or 120 mumol Cu(II)(5- DESS)/kg of body mass 3 hours before exposure to 8.0 Gy, gamma irradiation. In this paradigm, doses of Cu(II)(5- DESS) increased survival up to 92% above vehicle-treated control mice (P = 0.008). Mean body mass determinations revealed that mice treated with 80 to 120 mumol Cu(II)(5-DESS)/kg of body mass exhibited a smaller decrease in body mass than other complex-treated groups. These results support the hypothesis that Cu(II)(5-DESS) is an effective radioprotectant.