Neutron star properties with relativistic equations of state

We study the properties of neutron stars adopting relativistic equations of state of neutron star matter, calculated in the framework of the relativistic Brueckner-Hartree-Fock approximation for electrically charge neutral neutron star matter in beta-equilibrium. For higher densities more baryons (hyperons etc.) are included by means of the relativistic Hartree- or Hartree-Fock approximation. The special features of the different approximations and compositions are discussed in detail. Besides standard neutron star properties special emphasis is put on the limiting periods of neutron stars, for which the Kepler criterion and gravitation-reaction instabilities are considered. Furthermore the cooling behaviour of neutron stars is investigated, too. For comparison we give also the outcome for some nonrelativistic equations of state.Comment: 43 pages, 22 ps-figures, to be published in the International Journal of Modern Physics

Magnesium-impregnated biochar for the removal of total phosphorous from artificial human urine

Biochar has an alkaline and porous structure that could be a potential material for recycling phosphorous (P) from urine. Sawdust (SD) was pyrolyzed to produce sawdust biochar (SDB), and then impregnated with magnesium (Mg) to produce Mg-impregnated biochar (SDBM). Artificial human urine (AHU) solution was used for a batch sorption study, and various sorption parameters (i.e., sorbent/solution ratio, pH of AHU, and initial total P concentration of AHU) were optimized. The concentration of total P was measured using an inductively coupled plasma-optical emission spectroscopy (ICP-OES). The surface morphology and elemental analysis for SDB, SDBM and the struvite-loaded SDBM (SMSDB) were investigated using scanning electron spectroscopy-energy dispersive x-ray spectroscopy (SEM-EDX). The total P sorption capacity for SDBM (32755 mg/g) was higher than that of SDB (7782 mg/g) and SD (10682 mg/g). The optimum total P removal for SDBM (21.2%) was achieved at a sorbent/solution ratio of 0.06g/L at pH 9. Sorption of total P may have occurred on the heterogeneous surface of SDBM. The presence of struvite crystals indicates that phosphate was adsorbed and then precipitated on the surface of SDBM

Expedient synthesis and luminescence sensing of the inositol pyrophosphate cellular messenger 5-PP-InsP₅

Inositol pyrophosphates are important biomolecules associated with apoptosis, cell growth and kinase regulation, yet their exact biological roles are still emerging and probes do not exist for their selective detection. We report the first molecular probe for the selective and sensitive detection of the most abundant cellular inositol pyrophosphate 5-PP-InsP5, as well as an efficient new synthesis. The probe is based on a macrocyclic Eu(III) complex bearing two quinoline arms providing a free coordination site at the Eu(III) metal centre. Bidentate binding of the pyrophosphate group of 5-PP-InsP5 to the Eu(III) ion is proposed, supported by DFT calculations, giving rise to a selective enhancement in Eu(III) emission intensity and lifetime. We demonstrate the use of time-resolved luminescence as a bioassay tool for monitoring enzymatic processes in which 5-PP-InsP5 is consumed. Our probe offers a potential screening methodology to identify drug-like compounds that modulate the activity of enzymes of inositol pyrophosphate metabolism.</p