3,072 research outputs found
Picosecond electric-field-induced threshold switching in phase-change materials
Full text linkMany chalcogenide glasses undergo a breakdown in electronic resistance above
a critical field strength. Known as threshold switching, this mechanism enables
field-induced crystallization in emerging phase-change memory. Purely
electronic as well as crystal nucleation assisted models have been employed to
explain the electronic breakdown. Here, picosecond electric pulses are used to
excite amorphous AgInSbTe. Field-dependent reversible
changes in conductivity and pulse-driven crystallization are observed. The
present results show that threshold switching can take place within the
electric pulse on sub-picosecond time-scales - faster than crystals can
nucleate. This supports purely electronic models of threshold switching and
reveals potential applications as an ultrafast electronic switch.Comment: 6 pages manuscript with 3 figures and 8 pages supplementary materia
Randomized Phase III Trial of Pegfilgrastim versus Filgrastim after Autologus Peripheral Blood Stem Cell Transplantation
Get PDFNonrandomized trials suggest that pegfilgrastim, a pegylated granulocyte colony-stimulating factor, could be used in lieu of filgrastim after autologus peripheral blood stem cell transplantation. This phase III, randomized, double-blinded, placebo-controlled trial compared the efficacy, costs, and safety of single-dose pegfilgrastim (single 6mg dose) versus daily filgrastim (5μg/kg/day) for this indication. Seventy-eight patients, matched for age, sex, underlying disease, stage, and CD34/kg transplant dose were enrolled. Cytokines were started on day +1 posttransplant and continued to an absolute neutrophil count (ANC) of 5×109/L for 3 days or 10×109/L for 1 day. The median time to neutrophil engraftment (ANC >1.5×109/L for 3 days or 5×109/L for 1 day) was the same in both groups (12 days). No differences in platelet engraftment (11 versus 13 days), number of platelet transfusions (5 versus 4), percent with positive cultures for bacterial pathogens (23% versus 15%), days of fever (1 versus 2), deaths prior to engraftment (1 versus 1), or duration of hospital stay (19 versus 19 days) were seen between the pegfilgrastim and filgrastim groups, respectively. Using the average wholesale price for doses used in this trial, there was a per-patient savings of $961 for the pegfilgrastim group (P < .001). This phase III study failed to demonstrate a difference in time to neutrophil engraftment or any clinical sequelae between pegfilgrastim and filgrastim when given post-APBSCT, with pegfilgrastim achieving a cost savings over filgrastim
The cost of a single concussion in American high school football: A retrospective cohort study
Get PDFAim: The potential financial burden of American football-related concussions (FRC) is unknown. Our objective was to describe the healthcare costs associated with an FRC and determine factors associated with increased costs.
Methodology/results: A retrospective cohort study of concussed high school football players presenting between November 2017 and March 2020 was undertaken; 144 male high school football players were included. Total costs were about 800.10/concussion. Visiting the emergency department (β = 502.29, 95% CI: 105.79-898.61; p = 0.01), the initial post-concussion symptom scale score (β = 0.39, 95% CI: 0.11-0.66; p = 0.01) and a post-concussion syndrome diagnosis (β = 670.37, 95% CI: 98.96-1241.79; p = 0.02) were each independently associated with total costs.
Conclusion: A granular understanding of cost-driving factors associated with FRC is the first step in understanding the cost-effectiveness of prevention and treatment methods
AhrC and Eep are biofilm infection-associated virulence factors in enterococcus faecalis
Get PDFEnterococcus faecalis is part of the human intestinal microbiome and is a prominent cause of health care-associated infections. The pathogenesis of many E. faecalis infections, including endocarditis and catheter-associated urinary tract infection (CAUTI), is related to the ability of clinical isolates to form biofilms. To identify chromosomal genetic determinants responsible for E. faecalis biofilm-mediated infection, we used a rabbit model of endocarditis to test strains with transposon insertions or in-frame deletions in biofilm-associated loci: ahrC, argR, atlA, opuBC, pyrC, recN, and sepF. Only the ahrC mutant was significantly attenuated in endocarditis. We demonstrate that the transcriptional regulator AhrC and the protease Eep, which we showed previously to be an endocarditis virulence factor, are also required for full virulence in murine CAUTI. Therefore, AhrC and Eep can be classified as enterococcal biofilm-associated virulence factors. Loss of ahrC caused defects in early attachment and accumulation of biofilm biomass. Characterization of ahrC transcription revealed that the temporal expression of this locus observed in wild-type cells promotes initiation of early biofilm formation and the establishment of endocarditis. This is the first report of AhrC serving as a virulence factor in any bacterial species
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