Cartan F(R)F(R) Gravity and Equivalent Scalar-Tensor Theory

We investigate the Cartan formalism in $F(R)$ gravity. $F(R)$ gravity has been introduced as a theory to explain cosmological accelerated expansion by replacing the Ricci scalar $R$ in the Einstein-Hilbert action with a function of $R$. As is well-known, $F(R)$ gravity is rewritten as a scalar-tensor theory by using the conformal transformation. Cartan $F(R)$ gravity is described based on the Riemann-Cartan geometry formulated by the vierbein. In the Cartan formalism, the Ricci scalar $R$ is divided into two parts, one derived from the Levi-Civita connection and the other from the torsion. A kinetic term for a scalar field is constructed from the torsion part. It is shown that a class of the Cartan $F(R)$ gravity can be rewritten as an equivalent scalar-tensor theory without any conformal transformations. As a simple case, we apply the result to the Starobinsky model.Comment: 6 page

Quintessential Inflation in Logarithmic Cartan F(R)F(R) Gravity

We investigate the quintessential inflation in the logarithmic Cartan $F(R)$ gravity. A small logarithmic modification of the general relativity has the potential to introduce both inflation and dark energy. We evaluate the time evolution of the Universe such as inflation, reheating, and dark energy. The parameters in the model are fixed to introduce the inflation and the dark energy scales. We show that the CMB fluctuations induced by the inflation are consistent with the current observations. In the reheating process, it is possible to achieve the reheating temperature required for nucleosynthesis in Big Bang scenario. It can be seen that by choosing an appropriate value for the scalaron field after reheating, the scalaron field again dominates the energy of the Universe and causes the current accelerating expansion as dark energy.Comment: 16pages, 13figure

Scalar Mode Quadrupole Radiation from Astronomical Sources in F(R)F(R) Modified Gravity

We investigate the scalar mode quadrupole radiation of gravitational waves in $F(R)$ modified gravity. In $F(R)$ gravity a massive scalar mode appears in the gravitational waves. We find explicit expressions for the quadrupole radiation and the energy current of the scalar mode in general $F(R)$ gravity models. We consider a binary star and a bouncing star as astronomical sources of the gravitational waves and calculate the quadrupole radiation of the scalar and tensor modes. The scalar mode radiates under spherically symmetric conditions, but the tensor modes do not. The scalar mode mass is estimated for some typical energy scales. We show a possibility to detect the scalar mode in the future gravitational waves observation.Comment: 16pages, 2figure

The functions of Semaphorins in the neural development

During embryogenesis, axons reach their specific targets correctly to form the complex neural network found in the mature functional nervous system. Several groups of axon guidance molecules such as semaphorins, ephrins, netrins, and its have been reported to repel or attract the growing axons that express their cognate receptors. Semaphorins are secreted or transmembrane proteins, and found in both vertebrates and invertebrates. Semaphorins are initially identified as pulsive axon guidance molecules. However, recent many studies suggest that semaphorin family genes perform a variety of important biological functions besides the axon guidance

Antineoplastic activity of the combination of nilvadipine and 5'-deoxy-5-fluorouridine

An experiment was designed to study the efficacy of the combined administration of the nilvadipine as a calcium channel blocker which was estimated less toxic for heart. As for SCC-25 cells, KB cells and Hela cells, the effect of the combination of nilvadipine and 5'-DFUR was tested in vitro. Furthermore, each cell was stained immunohistochemically by ABC method and efficacy brought about by the combined administration of nilvadipine as a chemosensitizer was investigated. At the same time, each cell was studied from the view point of correlation with P-glycoprotein. As for SCC-25 cells, having incubated 48 hours, significantly additive effects in combination of 0.1μ gml-1 of nilvadipine and 16μ gml-1 of 5'-DFUR were recognized statistically (examination-I). KB cells showed the additive effect, but were not significant statistically. On the other hand, the immunohistochemical stain by ABC method was performed on SCC-25 and KB cells and it turned out that P-glycoprotein was positive. For further additive effects for 5'-DFUR by nilvadipine, it was indicated that the mechanism had been correlated with P-glycoprotein