Preheating constraints in α\alpha-attractor inflation and Gravitational Waves production

We propose a scenario where preheating occurs for a specific duration that is parametrized by an e-folds number $N_{pre}$, our results suggest a direct correlation between the preheating duration and the density of gravitational waves (GWs) produced during this phase. Moreover, we investigate the consequences of the inflationary parameters on the $\alpha$-attractor E model in the small $\alpha$ limits. In this framework, we perform investigations on the preheating parameters involving the number of e-folds $N_{pre}$, and the temperature of reheating $T_{re}$, then we show that the parameter $n$ associated with the E model of $\alpha$-attractor inflation has a negligible effect on the preheating duration, and we demonstrate that gravitational wave generation during preheating satisfies the restrictions from Planck's recent data.Comment: arXiv admin note: text overlap with arXiv:2209.0858

Quintessence like behavior of symmetric teleparallel dark energy: Linear and nonlinear model

In Einstein's General Relativity (GR), the gravitational interactions are described by the spacetime curvature. Recently, other alternative geometric formulations and representations of GR have emerged in which the gravitational interactions are described by the so-called torsion or non-metricity. Here, we consider the recently proposed modified symmetric teleparallel theory of gravity or $f\left( Q\right)$ gravity, where $Q$ represents the non-metricity scalar. In this paper, motivated by several papers in the literature, we assume the power-law form of the function $$ as $f\left( Q\right) =\alpha Q^{n+1}+\beta$ (where $$, $\beta$, and $n$ are free model parameters) that contains two models: Linear ($n=0$) and nonlinear ($n\neq 0$). Further, to add constraints to the field equations we assume the deceleration parameter form as a divergence-free parametrization. Then, we discuss the behavior of various cosmographic and cosmological parameters such as the jerk, snap, lerk, $Om$ diagnostic, cosmic energy density, isotropic pressure, and equation of state (EoS) parameter with a check of the violation of the strong energy condition (SEC) to obtain the acceleration phase of the Universe. Hence, we conclude that our cosmological $f(Q)$ models behave like quintessence dark energy (DE).Comment: Submitted to IJGMM

Dark matter via Baryogenesis: Affleck-Dine Mechanism in the Minimal Supersymmetric Standard Model

We conducted an investigation into Affleck-Dine baryogenesis within the context of D-term inflation, specifically focusing on its relationship with a recent reheating formalism. It was found that by considering a specific reheating temperature, the observed baryon asymmetry can be accounted through Affleck-Dine baryogenesis. Additionally, the majority of gravitinos are inferred to be generated from the decay of the next-to-lightest supersymmetric particle, with Q-balls potentially serving as a source of gravitinos via NSP decay. The temperature at which decay occurs depends on the charge of the Q-balls, which is determined by the fragmentation of the Affleck-Dine condensate. Remarkably, the gravitino mass required for dark matter aligns naturally with the theoretical gravitino mass.Comment: 11 pages, 4 figure

Gravitational Waves from Preheating in Gauss-Bonnet Inflation

We study gravitational wave production in an expanding Universe during the first stages following inflation, and investigate the consequences of the Gauss-Bonnet term on the inflationary parameters for a power-law inflation model with a GB coupling term. Moreover, we perform the analyses on the preheating parameters involving the number of e-folds $N_{pre}$, and the temperature of thermalization $T_{th},$ and show that it's sensitive to the parameters $n$, and $\gamma$, the parameter $\gamma$ is proposed to connect the density energy at the end of inflation to the preheating energy density. We set a correlation of gravitational wave energy density spectrum with the spectral index $n_{s}$ detected by the cosmic microwave background experiments$.$ The density spectrum $\Omega_{gw}$ shows good consistency with observation for $\gamma = 10^{3}$ and $10^{6}$. Our findings suggest that the generation of gravitational waves (GWs) during preheating can satisfy the constraints from Planck's data

Pre-radiotherapy plasma carotenoids and markers of oxidative stress are associated with survival in head and neck squamous cell carcinoma patients: a prospective study

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to compare plasma levels of antioxidants and oxidative stress biomarkers in head and neck squamous cell carcinoma (HNSCC) patients with healthy controls. Furthermore, the effect of radiotherapy on these biomarkers and their association with survival in HNSCC patients were investigated.</p> <p>Methods</p> <p>Seventy-eight HNSCC patients and 100 healthy controls were included in this study. Follow-up samples at the end of radiotherapy were obtained in 60 patients. Fifteen antioxidant biomarkers (6 carotenoids, 4 tocopherols, ascorbic acid, total antioxidant capacity, glutathione redox potential, total glutathione and total cysteine) and four oxidative stress biomarkers (total hydroperoxides, γ-glutamyl transpeptidase, 8-isoprostagladin F_2αand ratio of oxidized/total ascorbic acid) were measured in plasma samples. Analysis of Covariance was used to compare biomarkers between patients and healthy controls. Kaplan-Meier plots and Cox' proportional hazards models were used to study survival among patients.</p> <p>Results</p> <p>Dietary antioxidants (carotenoids, tocopherols and ascorbic acid), ferric reducing antioxidant power (FRAP) and modified FRAP were lower in HNSCC patients compared to controls and dietary antioxidants decreased during radiotherapy. Total hydroperoxides (d-ROMs), a marker for oxidative stress, were higher in HNSCC patients compared to controls and increased during radiotherapy. Among the biomarkers analyzed, high levels of plasma carotenoids before radiotherapy are associated with a prolonged progression-free survival (hazard rate ratio: 0.42, 95% CI: 0.20-0.91, p = 0.03). Additionally, high relative increase in plasma levels of d-ROMs (hazard rate ratio: 0.31, 95% CI: 0.13-0.76, p = 0.01) and high relative decrease in FRAP (hazard rate ratio: 0.42, 95% CI: 0.17-0.998, p = 0.05) during radiotherapy are also positively associated with survival.</p> <p>Conclusions</p> <p>Biomarkers of antioxidants and oxidative stress are unfavourable in HNSCC patients compared to healthy controls, and radiotherapy affects many of these biomarkers. Increasing levels of antioxidant biomarkers before radiotherapy and increasing oxidative stress during radiotherapy may improve survival indicating that different factors/mechanisms may be important for survival before and during radiotherapy in HNSCC patients. Thus, the therapeutic potential of optimizing antioxidant status and oxidative stress should be explored further in these patients.</p

Transcriptome Analysis of the Hippocampal CA1 Pyramidal Cell Region after Kainic Acid-Induced Status Epilepticus in Juvenile Rats

Molecular mechanisms involved in epileptogenesis in the developing brain remain poorly understood. The gene array approach could reveal some of the factors involved by allowing the identification of a broad scale of genes altered by seizures. In this study we used microarray analysis to reveal the gene expression profile of the laser microdissected hippocampal CA1 subregion one week after kainic acid (KA)-induced status epilepticus (SE) in 21-day-old rats, which are developmentally roughly comparable to juvenile children. The gene expression analysis with the Chipster software generated a total of 1592 differently expressed genes in the CA1 subregion of KA-treated rats compared to control rats. The KEGG database revealed that the identified genes were involved in pathways such as oxidative phosporylation (26 genes changed), and long-term potentiation (LTP; 18 genes changed). Also genes involved in Ca2+ homeostasis, gliosis, inflammation, and GABAergic transmission were altered. To validate the microarray results we further examined the protein expression for a subset of selected genes, glial fibrillary protein (GFAP), apolipoprotein E (apo E), cannabinoid type 1 receptor (CB1), Purkinje cell protein 4 (PEP-19), and interleukin 8 receptor (CXCR1), with immunohistochemistry, which confirmed the transcriptome results. Our results showed that SE resulted in no obvious CA1 neuronal loss, and alterations in the expression pattern of several genes during the early epileptogenic phase were comparable to previous gene expression studies of the adult hippocampus of both experimental epileptic animals and patients with temporal lobe epilepsy (TLE). However, some changes seem to occur after SE specifically in the juvenile rat hippocampus. Insight of the SE-induced alterations in gene expression and their related pathways could give us hints for the development of new target-specific antiepileptic drugs that interfere with the progression of the disease in the juvenile age group

Effect of the Diamagnetic term in the ultra-strong coupling regime

We consider a set of two level atoms interacting with a single quantized bosonic mode governed by the Dicke model. In this model it is well known that under a critical value of the light-matter coupling a spontaneous radiation process takes place. In the present work, we investigate the dynamics of the system and we study the Wigner distribution function to visualize the effect of the minimal coupling on the ground state wavefunction from the normal phase to the superradiant one. We show also that the entanglement of Bi-partite model is limited by the presence of the diamagnetic term

Primordial black holes and gravitational waves in teleparallel Gravity

In this paper, we consider the possible effect of the teleparallel gravity on the production of the primordial black holes (PBH) and on the gravitational waves (GWs). We investigate the relationship between the slow roll, the e-folds number and the teleparallel parameters. We show that in the case of the teleparallel parameter $$\delta =3$$, the e-folds number reaches the values 50 and 60 in consistency with the contour plot of the $$(r,n_{s})$$ plane obtained by Planck data at $$1\sigma$$ and $$2\sigma$$ C.L. Furthermore, we use the fraction of the energy density and the variance of the density perturbations approach to study the abundance of the production PBH. We find that the PBH overproduction can be satisfied for specific values of parameters of the non-adiabatic curvature power spectrum at some narrow parametric resonance. Moreover, to explain the GWs expected by observations, the duration of preheating should be bounded by values less or equal to 2. This bound is in agreement with values of the tensor-to-scalar ratio and the spectral index constrained by Planck data