40 research outputs found
Boson and neutron stars with increased density
We discuss boson stars and neutron stars, respectively, in a scalar-tensor
gravity model with an explicitly time-dependent real scalar field. While the
boson stars in our model -- in contrast to the neutron stars -- do not possess
a hard core, we find that the qualitative effects of the formation of scalar
hair are similar in both cases : the presence of the gravity scalar allows both
type of stars to exist for larger central density as well as larger mass at
given radius than their General Relativity counterparts. In particular, we find
new types of neutron stars with scalar hair which have radii very close to the
corresponding Schwarzschild radius and hence are comparable in density to black
holes. This new branch of solutions is stable with respect to the decay into
individual baryons.Comment: Matches version published in Phys. Lett.
Behaviour of a biocompatible titanium alloy during orthogonal micro-cutting employing green machining techniques
The sustainability of a process is the objective of modern industries aiming to reduce waste in production, since consumers require high quality and efficiency with fair price. Thus, a good understanding of the process should be its starting point. The manufacture of dental implants is an example in which waste reduction is important for the reduction of prices due to the demand for great quality and accuracy. This study observed the behaviour of sustainable micro-cutting applied to the Ti-6Al-7Nb titanium alloy, considering the ploughing effect on minimum quantity lubrication (MQL) and high-speed machining (HSM) conditions. When compared with dry condition and low-speed cutting in orthogonal micro-cutting, the use of HSM in dry cutting was more efficient than using MQL. The dry condition presented lower surface roughness, whilst the cooled/lubricated condition presented lower burr formation.publishe
Place of fibrates for the treatment of patients with atherogenic dyslipidemia
peer reviewedThe demography of dyslipidemia has changed towards a more complex atherogenic dyslipidemia involving increased levels of LDL cholesterol, in particular highly atherogenic small dense particles, hypertriglyceridemia and low HDL cholesterol, together with increased levels of markers of inflammation, thrombogenesis and endothelial dysfunction. Statins were shown to significantly lower cardiovascular morbidity and mortality, but treated patients are still left with a high residual risk, in particular for those with metabolic syndrome, type 2 diabetes, or low HDL cholesterol levels. Fibrates have been shown to reduce plasma triglycerides and increase HDL cholesterol, while improving inflammation, thrombogenesis and endothelial dysfunction. Clinical trials with fibrates have demonstrated their potential to reduce cardiovascular morbidity and mortality too, often through other mechanisms than those of statins. Combination trials of statins with fibrates have shown a more complete improvement of lipid profile and risk markers than each class separately. In contrast with gemfibrozil, fenofibrate does not interact significantly with the pharmacokinetics of statins, and its combination with statins has been shown to have a low risk of muscular side-effects or liver toxicity. The ACCORD outcome trial is exploring possible benefits of the combination of fenofibrate with statins on morbidity and mortality of patients with type 2 diabetes