Five Dimensional Cosmological Models in General Relativity

A Five dimensional Kaluza-Klein space-time is considered in the presence of a perfect fluid source with variable G and $\Lambda$. An expanding universe is found by using a relation between the metric potential and an equation of state. The gravitational constant is found to decrease with time as $G \sim t^{-(1-\omega)}$ whereas the variation for the cosmological constant follows as $\Lambda \sim t^{-2}$, $\Lambda \sim (\dot R/R)^2$ and $\Lambda \sim \ddot R/R$ where $\omega$ is the equation of state parameter and $R$ is the scale factor.Comment: 13 pages, 4 figures, accepted in Int. J. Theor. Phy

Changes in ferrous iron and glutathione promote ferroptosis and frailty in aging<em> Caenorhabditis elegans.</em>

All eukaryotes require iron. Replication, detoxification, and a cancer-protective form of regulated cell death termed ferroptosis, all depend on iron metabolism. Ferrous iron accumulates over adult lifetime in Caenorhabditis elegans. Here, we show that glutathione depletion is coupled to ferrous iron elevation in these animals, and that both occur in late life to prime cells for ferroptosis. We demonstrate that blocking ferroptosis, either by inhibition of lipid peroxidation or by limiting iron retention, mitigates age-related cell death and markedly increases lifespan and healthspan. Temporal scaling of lifespan is not evident when ferroptosis is inhibited, consistent with this cell death process acting at specific life phases to induce organismal frailty, rather than contributing to a constant aging rate. Because excess age-related iron elevation in somatic tissue, particularly in brain, is thought to contribute to degenerative disease, post-developmental interventions to limit ferroptosis may promote healthy aging

Physical, optical and thermoluminescence properties of lithium aluminum borate glass co-doped with Dy2O3

The present study aimed to evaluate the physical, optical, and thermoluminescence (TL) properties of Li2O–Al2O3–B2O3 as a function of adding Dy2O3 dopant concentrations varying from 0.0 to 0.8 mol%. The glasses were produced through the melt-quenching technique. The optimal concentration of Dy3+ ions for the 4F9/2 → 6H11/2 and 4F9/2 → 6H15/2 transition was found to be at 0.8 mol%. The glassy nature of the quenched samples was confirmed by the XRD pattern. All samples have been subjected to measurements of various physical properties, including density, molar volume, Polaron radius, inter-nuclear distance, ion concentration, and field strength. The most optimal sample exhibited exceptional linearity within the dose range of 0.5–5.0 Gy during gamma irradiation. The un-doped and Dy3+ doped glasses exhibited a linear correlation coefficient of 0.446 and 0.995, respectively, while their tissue-equivalent effective atomic numbers were 7.4 and 10.5. Over the course of a month, the glasses exhibited a fading rate of only 15%. After being exposed to 3.0 Gy of gamma rays, the samples for minimum detectable dose and reproducibility were examined. The kinetic parameters of the glasses under investigation, such as activation energies and kinetics orders, were determined using the peak shape method. According to the findings, the sample that contained 0.8 mol% of Dy2O3 exhibited exceptional thermoluminescence characteristics, indicating its potential as a dosimeter for measuring exposure to ionizing radiation