Spontaneous R-Parity Violation, A4A_4 Flavor Symmetry and Tribimaximal Mixing

We explore the possibility of spontaneous R parity violation in the context of $A_4$ flavor symmetry. Our model contains $SU(3)_c \times SU(2)_L \times U(1)_Y$ singlet matter chiral superfields which are arranged as triplet of $A_4$ and as well as few additional Higgs chiral superfields which are singlet under MSSM gauge group and belong to triplet and singlet representation under the $A_4$ flavor symmetry. R parity is broken spontaneously by the vacuum expectation values of the different sneutrino fields and hence we have neutrino-neutralino as well as neutrino-MSSM gauge singlet higgsino mixings in our model, in addition to the standard model neutrino- gauge singlet neutrino, gaugino-higgsino and higgsino-higgsino mixings. Because all of these mixings we have an extended neutral fermion mass matrix. We explore the low energy neutrino mass matrix for our model and point out that with some specific constraints between the sneutrino vacuum expectation values as well as the MSSM gauge singlet Higgs vacuum expectation values, the low energy neutrino mass matrix will lead to a tribimaximal mixing matrix. We also analyze the potential minimization for our model and show that one can realize a higher vacuum expectation value of the $SU(3)_c \times SU(2)_L \times U(1)_Y$ singlet sneutrino fields even when the other sneutrino vacuum expectation values are extremely small or even zero.Comment: 18 page

Laser Photosensitization of Cells By Hypericin

Administering a light dose of 90 J/cm(2) at 599 nm during incubation with hypericin to a highly differentiated normal epithelial cell line (FRTL-5), derived from Fisher rat thyroid, and to a neoplastic cell line (MPTK-6), derived from the lung metastases of a thyroid carcinoma induced in Fisher rats, produces cell kill at drug doses 1000 times lower than those necessary to cause the same mortality in the dark. The photocytocidal activity of this polycyclic quinone drag on neoplastic cells is superior to that of antitumor anthraquinone drugs, such as daunomycin and mitoxanthrone, and to the photosensitized antiviral activity previously reported for hypericin