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

The impact of residual renal function and total body water volume on achieving adequate dialysis in CAPD

Aims: The objective is to evaluate the impact of residual renal function (RRF) and total body water (TBW) on achieving adequate dialysis. Methods: Sixty three CAPD patients performing four 2 liter exchanges daily were evaluated for RRF, total weekly Kt/V (TWKt/V), total weekly creatinine clearance (TWCC) and TBW. Results: In patients with residual renal function (N = 41), TWKt/V and TWCC were 2.2 ± 0.8 and 77.4 ± 24.5 L, respectively. In patients without RRF (N = 22), TWKt/V was 1.6 ± 0.4 and TWCC 42.6 ± 9.2 L. TBW correlated negatively with TWKt/V in the group without RRF (r = -0.75, P\u3c0.001). Conclusion: It is not possible for larger patients without RRF treated with CAPD (2L x 4 exchanges) to achieve the acceptable targets for TWKt/V and TWCC due to TBW

Equal levels of blood pressure control in ESRD patients receiving high- efficiency hemodialysis and conventional hemodialysis

The present study compared the status of hypertension and adequacy of blood pressure control in 73 end-stage renal disease (ESRD) patients treated with four different modalities of hemodialysis, namely, conventional hemodialysis (CHD) with cuprophan 1.1m2 at a blood flow rate of 300 mL/min, high-efficiency hemodialysis (HED) with cuprophan 1.6 m2 at a blood flow rate of 450 to 500 mL/min, high-flux hemodialysis (HFD) with F80 polysulfone 1.8 m2 at a blood flow rate 500 mL/min, and high-flux hemodiafiltration (HDF) with F80 2 x 1.8 m2 in series at a blood flow rate of 600 to 650 mL/min. Thirty of the 73 patients (41/%) were receiving one or more antihypertensive agents to control their hypertension. The percentage of patients taking antihypertensive medication was less in the groups treated with HED, HFD, and HDF compared with the CHD group; 38%, 39%, and 39%, respectively, in the HED, HFD, and HDF groups versue 56% in the CHD group. Control of systolic hypertension was achieved in a higher percentage of patients treated with HED, HFD, and HDF compared with patients treated with CHD. Sixty-two percent of HED, 58% of HFD, and 61% of HDF patients compared with 44% of CHD patients had systolic blood pressure less than 150 mm Hg, whereas 77% of HED, 76% of HFD, and 78% of HDF patients compared 56% of CHD patients had diastolic blood pressure less than 90 mm Hg. However, the differences in the use of antihypertensive medication and control rates of hypertension did not reach statistical significance. The average blood pressure of all patients was 144/89 mm Hg; this did not differ significantly between the four groups. There also were no significant differences is etilogy of ESRD, hematocrit, biochemical data, as well as use and dose of recombinant human erythropoletin between the four groups. Compare with the CHD patients, the average treatment times with high-efficiency treatments were shorter, with HDF patients showing the shortest mean treatment time of 157 ± 41 minutes per hemodialysis session. The mean Kt/V was higher in the groups treated with HED, HFD, or HDF (1.31 ± 03, 1.30 ± 0.4, and 1.43 ± 0.3, respectively) then in the CHD group (1.12 ± 0.3; P \u3c 0.05). Interdialytic weight gain also did not differ among the four groups. There was no correlation between predialysis mean arterial pressure and either treatment time (r=0.04, P=NS), Kt/V (r = 0.03, P=NS), ultrafiltration rate (r=0.06, P=NS), or interdialytio weight gain (r= 0.08, P=NS). There also was no significant association between Kt/V and use of antihypertensive medications (chi-square = 1.76, P = NS). There was, however, a significant positive correlation between interdialytic weight gain and treatment time (r = 0.33, P \u3c 0.01). We conclude that the use of short dialysis sessions with efficient hemodialysis treatments, namely, HFD and HDF, was associated with similar levels of blood pressure control in ESRD patients

Biocompatibility of hemodialysis membranes: Interrelations between plasma complement and cytokine levels

Hemodialysis (HD) membrane biocompatibility is defined as absence of complement activation. We have recently shown that circulating levels of interleukin (IL) 1 and IL-2 predict death and survival, respectively, of HD patients. Studies have assessed IL-1 in treatments with biocompatible and less biocompatible dialysis membranes, but no study has correlated circulating levels of all these immunoreactants. We assessed these immunoreactants, and temperature as an outcome, during HD in patients treated with different membranes. Twelve stable patients, receiving thrice-weekly chronic bicarbonate HD, were randomly dialyzed with three different types of membranes, composed of: Cuprophan, cuprammonium rayon modified cellulose, and Hemophan. Blood was drawn from the arterial line port before (Pre) and 15, 30, and 60 min during and after (Post) HD. Patients\u27 temperatures were measured before and after each treatment. The plasma concentrations of IL-1 and IL-2 and factors C3a and C5a were assessed by ELISA. There were no differences between baseline levels of any of the immunoreactants in patients treated with different dialyzers. C3a, C5a, and IL-1 levels increased significantly during HD treatments with all three different membranes. C3a, C5a, and IL-1 levels during Cuprophan and Hemophan treatments were significantly higher than the levels during modified cellulose treatment at 30 and 60 min and Post (p \u3c 0.01). For all the immunoreactants, however, the Post levels were higher than the Pre levels. In contrast to IL-1, there were no differences in mean IL-2 levels during treatments when different membranes were compared. There were few correlations of plasma C3a and C5a levels with plasma IL-1 levels, but there was only one treatment time in one dialyzer group during which IL-2 and any of the other factors were correlated. Pre and Post temperature values and percent change in temperature were not correlated with any of the immunoreactants measured. These data show that C3a, C5a, and IL-1 responses are similar, but not identical, during treatments with different membranes. The response of circulating IL-2 levels to treatments is quite different from that of plasma C3a, C5a and IL-1 levels and suggests that these changes are not solely due to treatment factors. Treatment with modified cellulose membranes is associated with a different immunoreactive profile as compared with patients dialyzed using other cellulose membranes. We suggest that circulating IL-1 levels are good biocompatibility markers. Copyright © 2001 S. Karger AG, Basel

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