Non-relativistic radiation mediated shock breakouts: II. Bolometric properties of SN shock breakout

Exact bolometric light curves of supernova shock breakouts are derived based on the universal, non relativistic, planar breakout solutions (Sapir et al. 2011), assuming spherical symmetry, constant Thomson scattering opacity, \kappa, and angular intensity corresponding to the steady state planar limit. These approximations are accurate for progenitors with a scale height much smaller than the radius. The light curves are insensitive to the density profile and are determined by the progenitor radius R, and the breakout velocity and density, v_0 and \rho_0 respectively, and \kappa. The total breakout energy, E_BO, and the maximal ejecta velocity, v_max, are shown to be E_BO=8.0\pi R^2\kappa^-1cv_0 and v_max=2.0v_0 respectively, to an accuracy of about 10%. The calculated light curves are valid up to the time of transition to spherical expansion, t_sph\approx R/4v_0. Approximate analytic expressions for the light curves are provided for breakouts in which the shock crossing time at breakout, t_0=c/\kappa\rho_0v_0^2, is << R/c (valid for R<10^14 cm). Modifications of the flux angular intensity distribution and differences in shock arrival times to the surface, \Delta t_asym, due to moderately asymmetric explosions, affect the early light curve but do not affect v_max and E_BO. For 4v_0<<c, valid for large (RSG) progenitors, L\propto t^{-4/3} at max(\Delta t_asym,R/c)< t<t_sph and R may be accurately estimated from R\approx 2*10^13 (L/10^43 erg s^-1)^{2/5}(t/1 hr)^{8/15}

Non-relativistic radiation mediated shock breakouts: I. Exact bolometric planar breakout solutions

The problem of a non-steady planar radiation mediated shock (RMS) breaking out from a surface with a power-law density profile, \rho\propto x^n, is numerically solved in the approximation of diffusion with constant opacity. For an appropriate choice of time, length and energy scales, determined by the breakout opacity, velocity and density, the solution is universal, i.e. depends only on the density power law index n. The resulting luminosity depends weakly on the value of n. An approximate analytic solution, based on the self-similar hydrodynamic solutions and on the steady RMS solutions, is constructed and shown to agree with the numerical solutions as long as the shock is far from the surface, \tau>> c/v_{sh}. Approximate analytic expressions, calibrated based on the exact solutions, are provided, that describe the escaping luminosity as a function of time. These results can be used to calculate the bolometric properties of the bursts of radiation produced during supernova (SN) shock breakouts. For completeness, we also use the exact breakout solutions to provide an analytic approximation for the maximum surface temperature for fast (v_{sh}>~0.1) non-thermal breakouts, and show that it is few times smaller than inferred based on steady-state RMS solutions

Late life depression and concepts of aging: an emerging paradigm

Late life depression (LLD) is an emerging challenge, and recognized as a significant barrier to long-term healthy aging. Viewed within the context of the medical/biological model, advances in brain sciences over the last several decades have led to a deeper understanding of the biology of LLD. These advances in current knowledge include the description of aging brain pathophysiology; the biology and biochemistry of neurotransmitters; the correspondence between changes in neurological structure, function, and neural network; the description of neural, hormonal and inflammatory biomarkers; and identification of typical phenotypic subtypes of LLD. Despite these advances, current treatment of LLD, which remains largely pharmacological with accompanying cognitive and behavioral interventions, has poor success rate for long-term remission among older people. A wider perspective, in keeping with several emerging aging concepts, is suggested as an alternative framework within which to view LLD. A growing body of research supports the important role in LLD of frailty, resilience, intrinsic capacity, and functional integrity. Similarly, important social determinants need to be addressed in the etiology of LLD, rooted largely in negative stereotypes of aging, with consequent repercussions of reduced participation and inclusion, growing social isolation, with loss of identity, meaning and hope. This perspective suggests the importance of a wider integrative conceptualization of depression, set against a background of emerging aging concepts

Chemo-Radiotherapy of Oligometastases of Colorectal Cancer With Pegylated Liposomal Mitomycin-C Prodrug (Promitil): Mechanistic Basis and Preliminary Clinical Experience

Hypo-fractionated radiotherapy and stereotactic body radiotherapy are viable options for treatment of oligometastases. A prodrug of mitomycin-C is under clinical testing as a pegylated liposomal formulation (Promitil) with an improved safety profile over mitomycin-C. Promitil was offered to two patients with oligometastases from colorectal cancer as radiosensitizer. Each derived durable clinical benefit from Promitil administered immediately prior to and following irradiation. Transient toxicity to normal tissues of moderate to severe degree was observed. Promitil appears to have potential clinical value in this setting.HIGHLIGHTS- Delivery of radio-sensitizing drugs with pegylated (long-circulating) liposomes is a pharmacologically rational approach which remains largely clinically untested.- A mitomycin-c prodrug delivered by pegylated liposomes (Promitil) is activated by thiol groups, which are produced in excess by radiation-damaged cells, thus potentiating the radio-sensitizing effect of Promitil.- Two durable clinical responses in patient with colorectal oligometastases to Promitil and radiotherapy suggest that this approach may be of value in cancer chemo-radiotherapy