171 research outputs found
Stratigraphy, age, and provenance of the Eocene Chumstick basin, Washington Cascades; implications for paleogeography, regional tectonics, and development of strike-slip basins: Reply
We welcome the comment by Evans (2022) and the opportunity to further discuss our study of the Chumstick Formation. The correlation of fault-bound nonmarine sedimentary units in central and western Washington has been a topic of interest, and debate, for many years (Frizzell, 1979; Taylor et al., 1988; Gresens et al., 1981; Gresens, 1983; Evans and Johnson, 1989; Evans, 1994; Cheney and Hayman, 2009). However, many questions about the regional correlation of these units were resolved with the publication of a suite of internally consistent high-precision 206Pb/238U zircon dates from volcanic interbeds throughout the early to middle Eocene stratigraphy (Eddy et al., 2016). This data set confirmed the timing of sediment deposition of the different members within the Chumstick Formation. Donaghy et al. (2021) provides a detailed study of the Chumstick Formation, which builds on earlier research by Gresens et al. (1981, 1983), McClincy (1986), and Evans (1994) by incorporating new geochronologic information and additional clast counts, detrital zircon geochronology, and facies mapping. We interpret large parts of the Chumstick Formation to represent a spatially and temporally distinct sedimentary system between the Leavenworth and Entiat fault zones that likely formed as a pull-apart basin. Evans (2022) objects to several of the interpretations presented in Donaghy et al. (2021) regarding the relationship between different members of the Chumstick Formation and surrounding sedimentary units, the timing of strike-slip faulting, and the regional tectonic setting of these rocks. We discuss each of these points in the following sections
Cellular SNF2H Chromatin-Remodeling Factor Promotes Herpes Simplex Virus 1 Immediate-Early Gene Expression and Replication
Like other DNA viruses that replicate in the nucleus, herpes simplex virus 1 (HSV-1) regulates the association of histones with its genome to promote viral replication and gene expression. We previously demonstrated that SNF2H, a member of the ISWI family of chromatin-remodeling factors, is concentrated in HSV-1 replication compartments in the nuclei of infected cells, suggesting that this cellular enzyme plays a role in viral replication. We show here that small interfering RNA (siRNA)-mediated knockdown of SNF2H in HEp-2 cells resulted in an approximately 20-fold decrease in HSV-1 replication, arguing that SNF2H promotes efficient HSV-1 replication. Decreases in HSV-1 replication were observed with multiple SNF2H-specific siRNAs, and the extent of the replication decrease correlated with the amount of SNF2H knockdown, indicating that the phenotype resulted from decreased SNF2H levels rather than off-target effects of the siRNAs. We also observed a decrease in the accumulation of immediate-early (IE) gene products in HSV-1-infected cells in which SNF2H was knocked down. Histone H3 occupancy on viral promoters was increased in HSV-1-infected cells that were transfected with SNF2H-specific siRNAs, suggesting that SNF2H promotes removal of histones from viral promoters during infection. Furthermore, chromatin immunoprecipitation (ChIP) studies showed that SNF2H associated with the HSV-1 genome during infection, which suggests that SNF2H may directly remodel viral chromatin. We hypothesize that SNF2H is recruited to viral promoters during HSV-1 infection, where it can remodel the chromatin state of the viral genome, facilitate the transcription of immediate-early genes, and enhance viral replication
No Expanding Fireball: Resolving the Recurrent Nova RS Ophiuchi with Infrared Interferometry
Following the recent outburst of the recurrent nova RS Oph on 2006 Feb 12, we
measured its near-infrared size using the IOTA, Keck, and PTI Interferometers
at multiple epochs. The characteristic size of ~3 milliarcseconds hardly
changed over the first 60 days of the outburst, ruling out currently-popular
models whereby the near-infrared emission arises from hot gas in the expanding
shock. The emission was also found to be significantly asymmetric, evidenced by
non-zero closure phases detected by IOTA. The physical interpretation of these
data depend strongly on the adopted distance to RS Oph. Our data can be
interpreted as the first direct detection of the underlying RS Oph binary,
lending support to the recent ``reborn red giant'' models of Hachisu & Kato.
However, this result hinges on an RS Oph distance of ~< 540 pc, in strong
disagreement with the widely-adopted distance of ~1.6 kpc. At the farther
distance, our observations imply instead the existence of a non-expanding,
dense and ionized circumbinary gaseous disk or reservoir responsible for the
bulk of the near-infrared emission. Longer-baseline infrared interferometry is
uniquely suited to distinguish between these models and to ultimately determine
the distance, binary orbit, and component masses for RS Oph, one of the
closest-known (candidate) SNIa progenitor systems.Comment: Accepted by Astrophysical Journal Letter
Entropic, electrostatic, and interfacial regimes in concentrated disordered ionic emulsions
Acute tryptophan depletion evokes negative mood in healthy females who have previously experienced concurrent negative mood and tryptophan depletion
The Intrinsic Antiviral Defense to Incoming HSV-1 Genomes Includes Specific DNA Repair Proteins and Is Counteracted by the Viral Protein ICP0
Cellular restriction factors responding to herpesvirus infection include the ND10 components PML, Sp100 and hDaxx. During the initial stages of HSV-1 infection, novel sub-nuclear structures containing these ND10 proteins form in association with incoming viral genomes. We report that several cellular DNA damage response proteins also relocate to sites associated with incoming viral genomes where they contribute to the cellular front line defense. We show that recruitment of DNA repair proteins to these sites is independent of ND10 components, and instead is coordinated by the cellular ubiquitin ligases RNF8 and RNF168. The viral protein ICP0 targets RNF8 and RNF168 for degradation, thereby preventing the deposition of repressive ubiquitin marks and counteracting this repair protein recruitment. This study highlights important parallels between recognition of cellular DNA damage and recognition of viral genomes, and adds RNF8 and RNF168 to the list of factors contributing to the intrinsic antiviral defense against herpesvirus infection
Early mobilisation in intensive care units in Australia and Scotland:A prospective, observational cohort study examining mobilisation practises and barriers
Introduction: Mobilisation of patients in the intensive care unit (ICU) is an area of growing research. Currently, there is\ud
little data on baseline mobilisation practises and the barriers to them for patients of all admission diagnoses.\ud
Methods: The objectives of the study were to (1) quantify and benchmark baseline levels of mobilisation in Australian\ud
and Scottish ICUs, (2) compare mobilisation practises between Australian and Scottish ICUs and (3) identify barriers to\ud
mobilisation in Australian and Scottish ICUs. We conducted a prospective, observational, cohort study with a 4-week\ud
inception period. Patients were censored for follow-up upon ICU discharge or after 28 days, whichever occurred first.\ud
Patients were included if they were >18 years of age, admitted to an ICU and received mechanical ventilation in the ICU.\ud
Results: Ten tertiary ICUs in Australia and nine in Scotland participated in the study. The Australian cohort had a large\ud
proportion of patients admitted for cardiothoracic surgery (43.3 %), whereas the Scottish cohort had none. Therefore,\ud
comparison analysis was done after exclusion of patients admitted for cardiothoracic surgery. In total, 60.2 % of the 347\ud
patients across 10 Australian ICUs and 40.1 % of the 167 patients across 9 Scottish ICUs mobilised during their ICU stay\ud
(p < 0.001). Patients in the Australian cohort were more likely to mobilise than patients in the Scottish cohort (hazard\ud
ratio 1.83, 95 % confidence interval 1.38–2.42). However, the percentage of episodes of mobilisation where patients\ud
were receiving mechanical ventilation was higher in the Scottish cohort (41.1 % vs 16.3 %, p < 0.001). Sedation was the\ud
most commonly reported barrier to mobilisation in both the Australian and Scottish cohorts. Physiological instability\ud
and the presence of an endotracheal tube were also frequently reported barriers.\ud
Conclusions: This is the first study to benchmark baseline practise of early mobilisation internationally, and it\ud
demonstrates variation in early mobilisation practises between Australia and Scotland
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