Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

SFPQ promotes RAS-mutant cancer cell growth by modulating 5 '-UTR mediated translational control of CK1 alpha

10.1093/narcan/zcac027NAR CANCER4

MEK Inhibition Overcomes Cisplatin Resistance Conferred by SOS/MAPK Pathway Activation in Squamous Cell Carcinoma

10.1158/1535-7163.MCT-15-0062MOLECULAR CANCER THERAPEUTICS1471750-1760United State

The impact of the COVID-19 pandemic on irritable bowel syndrome

Background: Gastrointestinal manifestations of the COVID-19 pandemic may mimic Irritable Bowel Syndrome (IBS), and social distancing measures may affect IBS patients negatively. We aimed to study the impact of COVID-19 on respondents with IBS. Methods: We conducted an anonymised survey using MySurvey platform from May to June 2020 in 35 countries. The general public's knowledge, attitudes and practices regarding personal hygiene and social distancing during this COVID-19 pandemic and the psychological impact of COVID-19 were assessed. Statistical analysis was performed to determine the differences in well-being and compliance to social distancing measures between IBS and non-IBS respondents. Factors associated with worsening of IBS symptoms were evaluated. For newly developed IBS-like symptoms, subjects must fulfill ROME IV criteria. Results: Out of 2704 respondents, 2024 (74.9%) did not have IBS, 305 (11.3%) had IBS and 374 (13.8%) did not know what IBS was. Respondents with IBS reported significantly worse emotional, social and psychological well-being compared to non-IBS respondents and were less compliant to social distancing (28.2% vs 35.3%, p=0.029, table 1). Of the non-IBS respondents, 96 (4.7%) developed new IBS-like symptoms. Among IBS respondents, the majority reported no change in symptom severity (61.6%), while 26.6% reported improvement and 11.8% reported worsening in IBS symptoms. A higher proportion of respondents with no change in the severity of IBS symptoms was willing to practice social distancing indefinitely compared to those who deteriorated (74.9% vs 51.4%, p=0.016, table 2). In multivariate analysis (table 3), willingness to continue social distancing for only another 2–3 weeks was significantly associated with higher odds of worsening IBS while better emotional well-being was associated with lower odds. Conclusions: Our study showed differences in well-being and compliance to social distancing between IBS and non-IBS respondents, and these factors influence the worsening in severity of IBS. Further research will focus on how occupational stress and dietary changes may influence IBS symptoms

Factors associated with high compliance behaviour against COVID-19 in the early phase of pandemic: a cross-sectional study in 12 Asian countries

10.1136/bmjopen-2020-046310BMJ OPEN11