Evaluation of hexane and ethyl acetate extracts of the sponge Jaspis diastra collected from Mauritius Waters on HeLa cells

Objectives Based on previous screening results, the cytotoxic effect of the hexane (JDH) and ethyl acetate extracts (JDE) of the marine sponge Jaspis diastra were evaluated on HeLa cells and the present study aimed at determining their possible mechanism of cell death. Methods Nuclear staining, membrane potential change, flow cytometry analysis of cell cycle distribution and annexin V staining were undertaken to investigate the effects of JDE and JDH. Electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance were used to characterize an isolated bioactive molecule. Key findings JDE displayed an IC50 25 times more significant than the JDH. Flow cytometry analysis revealed JDE induced apoptosis in HeLa cells accompanied by the collapse of mitochondrial membrane potential. Fractionation of JDE resulted in the isolation of the known cytotoxic cyclodepsipeptide, Jaspamide. Conclusions Taking our results together suggest that JDE can be valuable for the development of anticancer drugs, especially for cervical cancer. Further investigations are currently in progress with the aim to determine and isolate other bioactive compounds from this extract.

Transverse Single Spin Asymmetries and Charmonium Production

We estimate transverse spin single spin asymmetry(TSSA) in the process e + p(up arrow) -> J/psi + X using color evaporation model of charmonium production. We take into account transverse momentum dependent(TMD) evolution of Sivers function and parton distribution function and show that the there is a reduction in the asymmetry as compared to our earlier estimates wherein the Q(2) - evolution was implemented only through DGLAP evolution of unpolarized gluon densities.

Effect of a mesh on boundary layer transitions induced by free-stream turbulence and an isolated roughness element

Streamwise streaks, their lift-up and streak instability are integral to the bypass transition process. An experimental study has been carried out to find the effect of a mesh placed normal to the flow and at different wall-normal locations in the late stages of two transitional flows induced by free-stream turbulence (FST) and an isolated roughness element. The mesh causes an approximately 30% reduction in the free-stream velocity, and mild acceleration, irrespective of its wall-normal location. Interestingly, when located near the wall, the mesh suppresses several transitional events leading to transition delay over a large downstream distance. The transition delay is found to be mainly caused by suppression of the lift-up of the high-shear layer and its distortion, along with modification of the spanwise streaky structure to an orderly one. However, with the mesh well away from the wall, the lifted-up shear layer remains largely unaffected, and the downstream boundary layer velocity profile develops an overshoot which is found to follow a plane mixing layer type profile up to the free stream. Reynolds stresses, and the size and strength of vortices increase in this mixing layer region. This high-intensity disturbance can possibly enhance transition of the accelerated flow far downstream, although a reduction in streamwise turbulence intensity occurs over a short distance downstream of the mesh. However, the shape of the large-scale streamwise structure in the wall-normal plane is found to be more or less the same as that without the mesh.

Prediction of electronically nonadiabatic decomposition mechanisms of isolated gas phase nitrogen-rich energetic salt: Guanidium-triazolate

Electronically nonadiabatic decomposition pathways of guanidium triazolate are explored theoretically. Nonadiabatically coupled potential energy surfaces are explored at the complete active space self-consistent field (CASSCF) level of theory. For better estimation of energies complete active space second order perturbation theories (CASPT2 and CASMP2) are also employed. Density functional theory (DFT) with B3LYP functional and MP2 level of theory are used to explore subsequent ground state decomposition pathways. In comparison with all possible stable decomposition products (such as, N-2, NH3, HNC, HCN, NH2CN and CH3NC), only NH3 (with NH2CN) and N-2 are predicted to be energetically most accessible initial decomposition products. Furthermore, different conical intersections between the S-1 and S-0 surfaces, which are computed at the CASSCF(14,10)/6-31G(d) level of theory, are found to play an essential role in the excited state deactivation process of guanidium triazolate. This is the first report on the electronically nonadiabatic decomposition mechanisms of isolated guanidium triazolate salt. (C) 2015 Elsevier B.V. All rights reserved.