Explore the vast range of titles available.

Using the Tsallis generalized entropy, holographic hypothesis and also considering the Hubble horizon as the IR cutoff, we build a holographic model for dark energy and study its cosmological consequences in the Brans–Dicke framework. At first, we focus on a non-interacting universe, and thereinafter, we study the results of considering a sign-changeable interaction between the dark sectors of the cosmos. Our investigations show that, compared with the flat case, the power and freedom of the model in describing the cosmic evolution is significantly increased in the presence of the curvature. The stability analysis also indicates that, independent of the universe curvature, both the interacting and non-interacting cases are classically unstable. In fact, both the classical stability criterion and an acceptable behavior for the cosmos quantities, including the deceleration and density parameters as well as the equation of state, are not simultaneously obtainable.

Using the first law of thermodynamics, we propose a relation between the system entropy (S) and its IR (L) and UV (\\[ \\]) cutoffs. In addition, applying this relation to the apparent horizon of flat FRW universe, whose entropy meets the Rényi entropy, a new holographic dark energy model is addressed. Thereinafter, the evolution of the flat FRW universe, filled by a pressureless source and the obtained dark energy candidate, is studied. In our model, there is no mutual interaction between the cosmos sectors. We find out that the obtained model is theoretically powerful to explain the current accelerated phase of the universe. This result emphasizes that the generalized entropy formalism is suitable for describing systems including the long-range interactions such as gravity.

We study some properties of the extended phase space of a quantum-corrected Schwarzschild black hole surrounded by a perfect fluid. In particular we demonstrate that, due to the quantum correction, there exist first and second order phase transitions for a certain range of the state parameter of the perfect fluid, and we explicitly analyze some cases. Besides that, we describe the efficiency of this system as a heat engine and the effect of quantum corrections for different surrounding fluids.

We extend one of the Hawking–Penrose singularity theorems in general relativity to the case of some scalar-tensor gravity theories in which the scalar field has a geometrical character and space-time has the mathematical structure of a Weyl integrable space-time. We adopt an invariant formalism, so that the extended version of the theorem does not depend on a particular frame.

Accepting the Komar mass definition of a source with energy-momentum tensor Tμν and using the thermodynamic pressure definition, we find a relaxed energy-momentum conservation law. Thereinafter, we study some cosmological consequences of the obtained energy-momentum conservation law. It has been found out that the dark sectors of cosmos are unifiable into one cosmic fluid in our setup. While this cosmic fluid impels the universe to enter an accelerated expansion phase, it may even show a baryonic behavior by itself during the cosmos evolution. Indeed, in this manner, while Tμν behaves baryonically, a part of it, namely, Tμν(e) which is satisfying the ordinary energy-momentum conservation law, is responsible for the current accelerated expansion.

We obtain new exact solutions for the gravitational field equations in the context of f ( R ,  T ) gravity, thereby obtaining different classes of black holes surrounded by fluids, taking into account some specific values of the parameter of the equations of state, w . In order to obtain these solutions in the context of f ( R ,  T ) gravity, we consider viable particular choices of the f ( R ,  T ). Considering an anisotropic energy-momentum tensor, we write the field equations with the required symmetries for this type of solution. Then, we analyze the conditions of energy in a general way and also for particular values of the parameter w of the equation of state. In addition, thermodynamic quantities, such as Hawking temperature and mass associated to the horizons of solutions, are taken into account in our analysis.

We analyze the extended phase space thermodynamics of Kiselev black hole introducing a central charge and allowing the gravitational constant to vary. We also discuss the relation between the chemical potential and the size of the black hole, besides the new description of phase transitions. We obtain as a conclusion that the universality of the central charge does not remain valid in general.

Chemokines and their receptors such as CCR2 and CX3CR1 mediate leukocyte adhesion and migration into injured tissue. To further define mechanisms of monocyte trafficking during kidney injury we identified two groups of F4/80-positive cells (F4/80low and F4/80high) in the normal mouse kidney that phenotypically correspond to macrophages and dendritic cells, respectively. Following ischemia and 3h of reperfusion, there was a large influx of F4/80low inflamed monocytes, but not dendritic cells, into the kidney. These monocytes produced TNF-α, IL-6, IL-1α and IL-12. Ischemic injury induced in CCR2−/− mice or in CCR2+/+ mice, made chimeric with CCR2−/− bone marrow, resulted in lower plasma creatinine levels and their kidneys had fewer infiltrated F4/80low macrophages compared to control mice. CX3CR1 expression contributed to monocyte recruitment into inflamed kidneys, as ischemic injury in CX3CR1−/− mice was reduced, with fewer F4/80low macrophages than controls. Monocytes transferred from CCR2+/+ or CX3CR1+/− mice migrated into reperfused kidneys better than monocytes from either CCR2−/− or CX3CR1−/− mice. Adoptive transfer of monocytes from CCR2+/+ mice, but not CCR2−/− mice, reversed the protective effect in CCR2−/− mice following ischemia-reperfusion. Egress of CD11b+Ly6Chigh monocytes from blood into inflamed kidneys was CCR2- and CX3CR1-dependent. Our study shows that inflamed monocyte migration, through CCR2- and CX3CR1-dependent mechanisms, plays a critical role in kidney injury following ischemia reperfusion.

We analyze the extended phase space thermodynamics of Kiselev black hole introducing a central charge and allowing the gravitational constant to vary. We also discuss the relation between the chemical potential and the size of the black hole, besides the new description of phase transitions. We obtain as a conclusion that the universality of the central charge does not remain valid in general.

We analyze how a quantum-gravity-induced change in the number of thermal dimensions (through a modified dispersion relation) affects the geometry and the thermodynamics of a charged black hole. To that end we resort to Kiselev's solution as the impact such modifications have on the evaporation rate of the black hole becomes more clear. As an application, we study the case for which the thermal dimension is reduced to two.