Photon surfaces are timelike, totally umbilic hypersurfaces of Lorentzian spacetimes. In the first part this paper, we locally characterize all possible photon in a class static, spherically symmetric spacetimes that includes Schwarzschild, Reissner--Nordstr\"om, Schwarzschild-anti de Sitter, etc., $n+1$ dimensions. second part, prove any vacuum, "asymptotically isotropic" $n+1$-dimensional spa...

objective: potato is the fourth important food crop after wheat, rice and maize. shrinkage  of  food  materials  has  a negative  consequence  on  the  quality  of  the dehydrated product. the main objective pursued in this paper is to investigate the shrinkage amount of potato slices during drying process using vacuum-infrared method. methods: in this work, the effect of the infrared radiation...

The behavior of intracellular potassium has been examined in ra t liver slices and in slices of dimethylaminoazobcnzcne-produccd hcpatomas. I t was found tha t both liver and hepatoma slices lost potassium during the first 15 minutes of incubation but then regained a portion of this during the ensuing 50-60 minutes. Hepa toma slices did not lose as much potassium as did liver slices, and the st...

1. The effect of spermidine on the mescaline-induced changes of brain-cortex ribosomes was studied by adding spermidine during the treatment of goat braincortex slices with mescaline. 2. Mescaline treatment of brain-cortex slices removed a portion of the endogenous spermidine from ribosomes and this removal was significantly prevented when spermidine was present during mescaline treatment. 3. S...

The effect of different concentrations of sugar solution (hypertonic) (30%, 45% and 60% w/v) and carboxyl methyl cellulose (CMC) (0%, 1% and 2% w/v) coating on freeze drying of apple slices was studied. In total, nine treatments with respect to concentrations of hypertonic solution and coating layer were prepared to analyze their influence on the physical and chemical properties of freeze dried...