Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylation Consortium, which encompass 59 tissue types across 185 mammalian species. These predictive models estimate mammalian tissue age with high accuracy (r > 0.96). Age deviations correlate with human mortality risk, mouse somatotropic axis mutations and caloric restriction. We identified specific cytosines with methylation levels that change with age across numerous species. These sites, highly enriched in polycomb repressive complex 2-binding locations, are near genes implicated in mammalian development, cancer, obesity and longevity. Our findings offer new evidence suggesting that aging is evolutionarily conserved and intertwined with developmental processes across all mammals.

The transport and thermodynamic properties of gas under contaminated conditions with Cu and PTFE vapours have been determined taking into account the new introduction of molecular particles, produced by chemical interactions between gas and impurities like CuF, , and , making in total 25 species. The main concern of this work is to predict, from the obtained material properties data, the transient behaviour of gas wall-stabilized arcs with these types of contamination that inevitably happen in gas circuit breakers during arc interruption. The results indicate that the electron density and the electrical conductivity increase with Cu vapour contamination, especially below 9000 K, due to the lower ionization potential of Cu atoms, but are almost invariant with PTFE contamination. The thermal conductivity changes only at higher admixture ratios above around 10% for both impurities. Typical increases in due to molecular dissociation have been found at temperatures around 4000 K for Cu vapour and at 3000 - 8000 K for PTFE vapour contamination. The transient behaviours of contaminated gas arcs have been analysed for step-current modulation in the wall-stabilized arcs under the condition of no gas flow. The greater value of arc conductance with Cu vapour contamination broadens the arc current channel, exposing possible disturbance of the current interruption function in gas circuit breakers. PTFE vapour contamination does not affect the arc decay process in wall-stabilized arcs significantly.

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Thermodynamic and transport properties such as mass density, enthalpy, specific heat, electrical and thermal conductivities and radiation power of N2/02 mixture plasmas at different admixture ratios were calculated in pressure range from 0.1 to 2 MPa on the assumption of thermal equilibrium condition. The first order approximation of Chapman-Enskog method was adopted to derive the transport properties. The thermodynamic and the transport properties thus derived were used to predict the temperature distributions and electric field strength of wall-stabilized N2/02 arcs in steady state at a current of 20 Ad, in order to investigate fundamental feature of N2/02 mixture arcs before current zero. The calculation revealed that the temperature at the center of the arcs had a local minimum value of 8800 K at an admixture ratio around 80% N2-20% O2 and whilst the conductance of the arc has a minimum at an admixture ratio of 100% N2 for pressure of 0.5 MPa in steady state.

A two-dimensional, axisymmetric model was developed to study the response of a radio-frequency inductively coupled plasma to a sudden change in its active power. The time-dependent equations for the conservation of mass, momentum, and energy, along with Maxwell’s equations were solved numerically. Results were obtained for a pressure range of 200–760 Torr, a frequency range of 1–3 MHz; torch diameters between 40 and 75 mm; and, argon/hydrogen flow rates of 40–75 slpm. Initially, the plasma was assumed to be under steady-state condition at 20 kW. The plasma power was then reduced to 10 kW for 35 ms and, the response of the plasma fields and the coil current were predicted numerically. When power was reduced, the coil current reduced significantly in 2 ms. It then increased to a maximum before smoothly decreasing to its new steady-state value. The response of the plasma depended, to different degrees, on all the parameters considered here. Depending on the position within the torch, it could vary from 2 ms to several tens of millisecond. The plasma response was fastest within the skin-depth region where power was dissipated. The response time was most strongly affected by the changes in discharge pressure; and was least affected by the induction frequency. The response time increased with pressure and/or torch diameter, and decreased with frequency and/or flow rate. We also found that, depending on the magnitude of induction frequency, an increase in plasma power may cause an oscillatory plasma behavior.