Effects of X-rays on vascular function in transplanted tumours and normal tissues in the mouse.

The effects of X-radiation on the Nembutal-induced redistribution of the cardiac output in two types of transplanted mouse tumours and some normal mouse tissues have been investigated, using rubidium-86 and 125I-human serum albumin. Irradiation causes an increase in 86Rb uptake (relative blood perfusion) by the tumours of anaesthetized mice, but has little or no effect in non-anaesthetized mice. The increase is dose- and time-dependent. Tumour plasma space is not significantly affected by radiation and Nembutal. Muscle blood perfusion is severely decreased in anaesthetized mice and is not affected by radiation, at least within the time limits of the experiments. This means that radiation-induced functional vascular changes in normal and neoplastic tissues follow different time courses. On the basis of the present results, and of the results of other authors, it is argued that irradiation damages the vasculature of tumours in such a way that it becomes more sensitive to changes in systemic blood pressure

The effect of anaesthetics on blood perfusion in transplanted mouse tumours.

Rubidium-86, 125I-human serum albumin and 51Cr-labelled red cells have been used to investigate the effects of the anaesthetics Nembutal (pentobarbitone sodium) and urethane on blood perfusion, blood volume and albumin leakage in 5 types of transplanted mouse tumour and in normal organs. Nembutal was found to increase the relative blood perfusion by a factor of 1-3 to 2-0 in tumours and by a factor of 1-7 to 3-0 in kidneys but muscle perfusion fell to 0-3-0-5 that of controls. The effects of urethane were found to be dose dependent, generally in the same direction as for Nembutal, and smaller. Both anaesthetics reduced the blood volume of tumours (except for the C3H mammary carcinoma) and of kidneys by factors of 0-2 to 0-8. The duration of anaesthesia had no effect on the plateau values of relative blood perfusion and blood volume in either tumours or normal organs, but Nembutal delayed slightly the 86Rb uptake and decreased the rate of albumin leakage

Analysis of Deterioration in a Plasma Focus Device

Indexación: Scopus.The Plasma Focus (PF) is a kind of dense transient plasmas in with high-pulsed voltage. To produce devices for eld application it is necessary to obtain PF equipment able to operate for a long period of time. Thus, a reliability analysis is indispensable. In this work a reliability analysis program for plasma focus devices is presented. The program considers a criticality analysis using Failure Modes and Effects Criticality Analysis (FMECA) to identify the most important failure modes of the system. Said failure modes are studied operating the Plasma Focus for many cycles, obtaining from them the characteristic curves of V(t) and İ(t). Feature Extraction (FE) techniques are applied to obtain a list of parameters that correlate to the degrading process. Furthermore, Machine Learning tools are used to learn from the obtained data, linking the changes in these parameters during its life cycle to the decay of the system in hope for future implementation of a predictive maintenance system and a reference for data analysis and prediction in PFs. The study was applied to a portable plasma focus device operated at 2 joules of stored energy. © Published under licence by IOP Publishing Ltd.The work is supported by IAEA CRP contract 20370 and by grant ACT-1115, CONICYT, Chile.https://iopscience.iop.org/article/10.1088/1742-6596/1043/1/01204

The Black Hole in Three Dimensional Space Time

The standard Einstein-Maxwell equations in 2+1 spacetime dimensions, with a negative cosmological constant, admit a black hole solution. The 2+1 black hole -characterized by mass, angular momentum and charge, defined by flux integrals at infinity- is quite similar to its 3+1 counterpart. Anti-de Sitter space appears as a negative energy state separated by a mass gap from the continuous black hole spectrum. Evaluation of the partition function yields that the entropy is equal to twice the perimeter length of the horizon.Comment: This version is the one that appeared in PRL (1992), and has important improvements with respect to the one previously submitted to the archive. 13 pages, latex, no figure

de Sitter black hole with a conformally coupled scalar field in four dimensions

A four-dimensional black hole solution of the Einstein equations with a positive cosmological constant, coupled to a conformal scalar field, is given. There is a curvature singularity at the origin, and scalar field diverges inside the event horizon. The electrically charged solution, which has a fixed charge-to-mass ratio is also found. The quartic self-interacting coupling becomes bounded in terms of Newton's and the cosmological constants.Comment: 5 pages, no figures, CECS style, energy conditions are discussed and some references were added. To appear in Phys. Rev.

Recycling of bottom ash from biomass combustion in porcelain stoneware tiles: Effects on technological properties, phase evolution and microstructure

This work aims to evaluate the use of bottom biomass ash as an alternative raw material in porcelain stoneware bodies. For this purpose, ash coming from a biomass thermoelectric power plant in Emilia-Romagna (Italy) was selected and its chemical, mineralogical and thermal properties determined. Data indicated its technological role as a flux, so it was introduced in a porcelain stoneware batch in partial replacement of feldspars and experimented at laboratory scale. A bottleneck, relative to the rheological behavior of the slips, was overcome by a slight deflocculant increase. The powder compacts were fired from 1000° to 1220 °C in order to follow the evolution of the technological properties, phase composition (XRPD-Rietveld) and microstructure (SEM). The introduction of ash allowed to lower the firing temperature by 20 °C, while keeping the technological properties comparable with those of the benchmark. Moreover, the mineralogical and microstructural data revealed different sintering kinetics

Thermodynamics of Black Holes in Schroedinger Space

A black hole and a black hyperboloid solutions in the space with the Schroedinger isometries are presented and their thermodynamics is examined. The on-shell action is obtained by the difference between the extremal and non-extremal ones with the unusual matching of the boundary metrics. This regularization method is first applied to the black brane solution in the space of the Schroedinger symmetry and shown to correctly reproduce the known thermodynamics. The actions of the black solutions all turn out to be the same as the AdS counterparts. The phase diagram of the black hole system is obtained in the parameter space of the temperature and chemical potential and the diagram contains the Hawking-Page phase transition and instability lines.Comment: 20 page

Back-reaction of a conformal field on a three-dimensional black hole

The first order corrections to the geometry of the (2+1)-dimensional black hole due to back-reaction of a massless conformal scalar field are computed. The renormalized stress energy tensor used as the source of Einstein equations is computed with the Green function for the black-hole background with transparent boundary conditions. This tensor has the same functional form as the one found in the nonperturbative case which can be exactly solved. Thus, a static, circularly symmetric and asymptotically anti-de Sitter black hole solution of the semiclassical equations is found. The corrections to the thermodynamic quantities are also computed.Comment: 12 pages, RevTeX, no figure