Mining Circumgalactic Baryons in the Low-Redshift Universe

(Abridged) This paper presents an absorption-line study of the multiphase circumgalactic medium (CGM) based on observations of Lya, CII, CIV, SiII, SiIII, and SiIV absorption transitions in the vicinities of 195 galaxies at redshift z<0.176. The galaxy sample is established based on a cross-comparison between public galaxy and QSO survey data and is characterized by a median redshift of =0.041, a median projected distance of =362 kpc to the sightline of the background QSO, and a median stellar mass of log(M_star/M_sun) = 9.7 \pm 1.1. Comparing the absorber features identified in the QSO apectra with known galaxy properties has led to strong constraints for the CGM absorption properties at z<~0.176. First, abundant hydrogen gas is observed out to d~500 kpc, well beyond the dark matter halo radius Rh of individual galaxies, with a mean covering fraction of ~60%. In contrast, no heavy elements are detected at d>~0.7 Rh from either low-mass dwarfs or high-mass galaxies. The lack of detected heavy elements in low- and high-ionization states suggests that either there exists a chemical enrichment edge at d~0.7 Rh or gaseous clumps giving rise to the observed absorption lines cannot survive at these large distances. Considering all galaxies at d>Rh leads to a strict upper limit for the covering fraction of heavy elements of ~3% (at a 95% confidence level) over d=(1-9) Rh. At d<Rh, differential covering fraction between low- and high-ionization gas is observed, suggesting that the CGM becomes progressively more ionized from d<0.3 Rh to larger distances. Comparing CGM absorption observations at low and high redshifts shows that at a fixed-fraction of Rh the CGM exhibits stronger mean absorption at z=2.2 than at z~0. We discuss possible pseudo-evolution of the CGM as a result of misrepresentation of halo radius.Comment: 25 pages, 13 figures; accepted for publication in MNRA

Modulation of Dendritic Cells with the Interleukin-10 Gene on Polycation-Modified Polymeric Particles

Gene therapy has emerged as a field to modulate cell functions by introducing genes of interest to target cells. An emerging focus in this field is to employ non-viral vectors to deliver immunosuppressive cytokines to dendritic cells (DCs) to attenuate damaging immune responses. DCs serve as potential targets for suppression of T cell responses. In this work, we investigated the ability of polycation-modified polymeric particles complexed with interleukin-10 (IL-10) gene to modulate DCs. The delivery systems (designated as PSO10H6 and PLGAO10H6) were formed by coating cationic peptide O10H6 (O: ornithine; H: histidine) on the polystyrene (PS) and poly (lactic-co-glycolic acid) (PLGA) particulates. A mouse IL-10 encoding plasmid (pIL-10) was loaded on the surface of PSO10H6 and PLGAO10H6 via ionic interactions. Physical characterization of these particles revealed stable colloidal dispersions (diameters: 297.2±14nm in PLGAO10H6-pIL-10 and 126.0±8nm in PSO10H6-pIL-10). DNA molecules carried by PSO10H6 and PLGAO10H6 were protected from serum digestion. Results from in vitro gene transfection studies showed two-fold enhancement of IL-10 expression in bone marrow-derived DCs transfected with PSO10H6-pIL-10 and PLGAO10H6-pIL-10 compared to untransfected DCs. Their suppressive functions were evaluated in an in vitro mixed lymphocyte model. Results indicated that PSO10H6-pIL-10 and PLGAO10H6-pIL-10 modified DCs elicited weakest proliferation of allogeneic bulk T cells as well as CD4 and CD8 T cells among all the delivery modes. Using cell-embedded Matrigel as a surrogate graft, we showed that IL-10 gene-modified DCs suppressed host cell infiltration in vivo. These data suggested PSO10H6-pIL-10 and PLGAO10H6-pIL-10 deliver an overriding suppressive signal to T cells. Further studies revealed T cells stimulated by the IL-10 gene-modified DCs exhibited characteristics of regulatory T (Treg) cells, as evident by up-regulation of a Treg cell marker forkhead-type transcription factor 3 (Foxp3). This result was concomitant with an increase in of transforming growth factor beta (TGF-beta) production. Taken together, this work demonstrated that PSO10H6 and PLGAO10H6 are effective in delivering pIL-10 to modulate DCs to suppress T cell responses. Collectively, the results raise the prospects of using PSO10H6 and PLGAO10H6 as vectors to deliver immunosuppressive genes to modulate T cell responses in vivo

ADAPTIVE VOLTAGE CONVERSION FOR ENERGY EFFICIENT COMPUTING

A server rack may require DC voltages at various levels such as 12 volts, 1.8 volts, 1.2 volts, etc. that are suitable for different computing devices. In operation, a supply voltage is converted to the voltage required by corresponding computing devices. The voltage-level conversion is done in stages. A first stage converts from the supply voltage, e.g., 48 volts, to an intermediate voltage, e.g., in the range 7 to 15 volts. A second stage converts from the intermediate voltage to the appropriate output voltage. Efficiency of power conversion system varies with load, and depends on the intermediate voltage. This document describes techniques to measure conversion efficiency and adapt the intermediate voltage to optimize efficiency of power conversion system

Machine Learning for Accurate Battery Run Time Prediction

Generally, the present disclosure is directed to using machine learning to manage state of charge of a battery. In particular, in some implementations, the systems and methods of the present disclosure can include or otherwise leverage one or more machine-learned models to predict future energy consumption and optimal charging rate of a battery based on battery characteristics and expected user routine