264 research outputs found
A search for 21 cm HI absorption in AT20G compact radio galaxies
We present results from a search for 21 cm associated HI absorption in a
sample of 29 radio sources selected from the Australia Telescope 20 GHz survey.
Observations were conducted using the Australia Telescope Compact Array
Broadband Backend, with which we can simultaneously look for 21 cm absorption
in a redshift range of 0.04 < z < 0.08, with a velocity resolution of 7 km/s .
In preparation for future large-scale H I absorption surveys we test a
spectral-line finding method based on Bayesian inference. We use this to assign
significance to our detections and to determine the best-fitting number of
spectral-line components. We find that the automated spectral-line search is
limited by residuals in the continuum, both from the band-pass calibration and
spectral-ripple subtraction, at spectral-line widths of \Deltav_FWHM > 103 km/s
. Using this technique we detect two new absorbers and a third, previously
known, yielding a 10 per cent detection rate. Of the detections, the
spectral-line profiles are consistent with the theory that we are seeing
different orientations of the absorbing gas, in both the host galaxy and
circumnuclear disc, with respect to our line-of-sight to the source. In order
to spatially resolve the spectral-line components in the two new detections,
and so verify this conclusion, we require further high-resolution 21 cm
observations (~0.01 arcsec) using very long baseline interferometry.Comment: 16 pages, 8 figures and 5 tables; accepted for publication in MNRAS
(version 2 based on proof corrections
Reliability and Repeatability of Cone Density Measurements in Patients With Stargardt Disease and RPGR-Associated Retinopathy
PURPOSE: To assess reliability and repeatability of cone density measurements by using confocal and (nonconfocal) split-detector adaptive optics scanning light ophthalmoscopy (AOSLO) imaging. It will be determined whether cone density values are significantly different between modalities in Stargardt disease (STGD) and retinitis pigmentosa GTPase regulator (RPGR)–associated retinopathy.
METHODS: Twelve patients with STGD (aged 9–52 years) and eight with RPGR-associated retinopathy (aged 11–31 years) were imaged using both confocal and split-detector AOSLO simultaneously. Four graders manually identified cone locations in each image that were used to calculate local densities. Each imaging modality was evaluated independently. The data set consisted of 1584 assessments of 99 STGD images (each image in two modalities and four graders who graded each image twice) and 928 RPGR assessments of 58 images (each image in two modalities and four graders who graded each image twice).
RESULTS: For STGD assessments the reliability for confocal and split-detector AOSLO was 67.9% and 95.9%, respectively, and the repeatability was 71.2% and 97.3%, respectively. The differences in the measured cone density values between modalities were statistically significant for one grader. For RPGR assessments the reliability for confocal and split-detector AOSLO was 22.1% and 88.5%, respectively, and repeatability was 63.2% and 94.5%, respectively. The differences in cone density between modalities were statistically significant for all graders.
CONCLUSIONS: Split-detector AOSLO greatly improved the reliability and repeatability of cone density measurements in both disorders and will be valuable for natural history studies and clinical trials using AOSLO. However, it appears that these indices may be disease dependent, implying the need for similar investigations in other conditions
Infrared spectral studies of Zn-substituted CuFeCrO4 spinel ferrite system
The spinel solid solution series Znx Cu1–x FeCrO4 with x = 0.0,0.2,0.4 and 0.6 has been studied by infrared absorption spectroscopy. The IR-spectrum showed two main absorption bands ν1 and ν2 in the range 400-600 cm-1 arising from tetrahedral (A) and octahedral (B) interstitial sites in the spinel lattice. The absence of ν4 band suggests that lattice vibrations are insignificant. No shoulder or splitting is observed around ν1 and ν2 bands confirming absence of Fe+2 ions in the system. The sharpening of band with Zn- content (x) is due to the fact that the system changes from inverse to normal spinel structure. The structural and optical properties are correlated and the bulk modulus, compressional and shear velocity values determined through IR spectral analysis are in good agreement to those obtained through ultrasonic pulse transmission technique.Author Affiliation: M C Chhantbar, U N Trivedi, P V Tanna, H J Shah, R P Vara, H H Joshi and K B Modi
Department of Physics, Saurashtra University,
Rajkot-360 005, Gujarat, India
E-mail : [email protected] of Physics, Saurashtra University,
Rajkot-360 005, Gujarat, Indi
Balanced Crystalloids versus Saline in Critically Ill Adults — A Systematic Review with Meta-Analysis
BACKGROUND: The comparative efficacy and safety of balanced crystalloid solutions and saline for fluid therapy in critically ill adults remain uncertain. METHODS: We systematically reviewed randomized clinical trials (RCTs) comparing the use of balanced crystalloids with saline in critically ill adults. The primary outcome was 90-day mortality after pooling data from low-risk-of-bias trials using a random-effects model. We also performed a Bayesian meta-analysis to describe the primary treatment effect in probability terms. Secondary outcomes included the incidence of acute kidney injury (AKI), new treatment with renal replacement therapy (RRT), and ventilator-free and vasopressor-free days to day 28. RESULTS: We identified 13 RCTs, comprising 35,884 participants. From six trials (34,450 participants) with a low risk of bias, the risk ratio (RR) for 90-day mortality with balanced crystalloids versus saline was 0.96 (95% confidence interval [CI], 0.91 to 1.01; I2 = 12.1%); using vague priors, the posterior probability that balanced crystalloids reduce mortality was 89.5%. The RRs of developing AKI and of being treated with RRT with balanced crystalloids versus saline were 0.96 (95% CI, 0.89 to 1.02) and 0.95 (95% CI, 0.81 to 1.11), respectively. Ventilator-free days (mean difference, 0.18 days; 95% CI, −0.45 to 0.81) and vasopressor-free days (mean difference, 0.19 days; 95% CI, −0.14 to 0.51) were similar between groups. CONCLUSIONS: The estimated effect of using balanced crystalloids versus saline in critically ill adults ranges from a 9% relative reduction to a 1% relative increase in the risk of death, with a high probability that the average effect of using balanced crystalloids is to reduce mortality
Cardiorenal protective effects of canagliflozin in CREDENCE according to glucose lowering
Introduction Relationships between glycemic-lowering effects of sodium glucose co-transporter 2 inhibitors and impact on kidney and cardiovascular outcomes are uncertain. Research design and methods We analyzed 4395 individuals with prebaseline and postbaseline hemoglobin A1c (HbA1c) randomized to canagliflozin (n=2193) or placebo (n=2202) in The Canagliflozin and Renal Events in Diabetes with Established Nephropathy Clinical Evaluation trial. Effects on HbA1c were assessed using mixed models. Mediation of treatment effects by achieved glycemic control was analyzed using proportional hazards regression with and without adjustment for achieved HbA1c. End points included combined kidney or cardiovascular death, end-stage kidney disease or doubling of serum creatinine (primary trial outcome), and individual end point components. Results HbA1c lowering was modified by baseline estimated glomerular filtration rate (eGFR). For baseline eGFR 60-90, 45-59, and 30-44 mL/min/1.73 m 2, overall HbA1c (canagliflozin vs placebo) decreased by -0.24%, -0.14%, and -0.08% respectively and likelihood of >0.5% decrease in HbA1c decreased with ORs of 1.47 (95% CI 1.27 to 1.67), 1.12 (0.94 to 1.33) and 0.99 (0.83 to 1.18), respectively. Adjustment for postbaseline HbA1c marginally attenuated canagliflozin effects on primary and kidney composite outcomes: unadjusted HR 0.67 (95% CI 0.57 to 0.80) and 0.66 (95% CI 0.53 to 0.81); adjusted for week 13 HbA1c, HR 0.71 (95% CI 0.060 to 0.84) and 0.68 (95% CI 0.55 to 0.83). Results adjusted for time-varying HbA1c or HbA1c as a cubic spline were similar and consistent with preserved clinical benefits across a range of excellent and poor glycemic control. Conclusions The glycemic effects of canagliflozin are attenuated at lower eGFR but effects on kidney and cardiac end points are preserved. Non-glycemic effects may be primarily responsible for the kidney and cardioprotective benefits of canagliflozin.2
Cost-Effectiveness of a Household Salt Substitution Intervention: Findings From 20 995 Participants of the Salt Substitute and Stroke Study
Background: SSaSS (Salt Substitute and Stroke Study), a 5-year cluster randomized controlled trial, demonstrated that replacing regular salt with a reduced-sodium, added-potassium salt substitute reduced the risks of stroke, major adverse cardiovascular events, and premature death among individuals with previous stroke or uncontrolled high blood pressure living in rural China. This study assessed the cost-effectiveness profile of the intervention. Methods: A within-trial economic evaluation of SSaSS was conducted from the perspective of the health care system and consumers. The primary health outcome assessed was stroke. We also quantified the effect on quality-adjusted life-years (QALYs). Health care costs were identified from participant health insurance records and the literature. All costs (in Chinese yuan [¥]) and QALYs were discounted at 5% per annum. Incremental costs, stroke events averted, and QALYs gained were estimated using bivariate multilevel models. Results: Mean follow-up of the 20 995 participants was 4.7 years. Over this period, replacing regular salt with salt substitute reduced the risk of stroke by 14% (rate ratio, 0.86 [95% CI, 0.77-0.96]; P=0.006), and the salt substitute group had on average 0.054 more QALYs per person. The average costs (¥1538 for the intervention group and ¥1649 for the control group) were lower in the salt substitute group (¥110 less). The intervention was dominant (better outcomes at lower cost) for prevention of stroke as well as for QALYs gained. Sensitivity analyses showed that these conclusions were robust, except when the price of salt substitute was increased to the median and highest market prices identified in China. The salt substitute intervention had a 95.0% probability of being cost-saving and a >99.9% probability of being cost-effective. Conclusions: Replacing regular salt with salt substitute was a cost-saving intervention for the prevention of stroke and improvement of quality of life among SSaSS participants
Ready-to-use food supplement, with or without arginine and citrulline, with daily chloroquine in Tanzanian children with sickle-cell disease: a double-blind, random order crossover trial
Background: Sickle cell disease increases malnutrition risk. Low arginine and nitric oxide [NO] bioavailability are implicated in sickle-related morbidity. Simple interventions are required, especially in low-income settings. We aimed to test the hypotheses: (1) supplementary arginine, citrulline and daily chloroquine increases bioavailable arginine and flow-mediated-dilatation (FMDmax%; a measure of NO-dependent endothelial function), and (2); protein energy supplementation in the form of ready-to-use supplementary-food (RUSF) improves nutritional status in children with sickle cell disease.
Methods: A random-order, double-blind, cross-over trial with two four-month intervention periods (each followed by four-months wash-out) was conducted in Dar-es-Salaam, Tanzania. 119 children aged 8-12 years, naïve to hydroxyurea, were enrolled from the Muhimbili National Hospital Sickle Cohort. The random order sequence and allocation codes were generated centrally. Two formulations of RUSF (500kcal/day) were tested: ‘basic’ with weekly chloroquine (150/225mg base, depending on weight) (RUSF-b) and ‘vascular’ (RUSF-v) fortified with arginine, citrulline designed to achieve mean intakes of 0.2g/0.1g/kg/day and daily chloroquine (max 3mg base/kg/day). The primary outcomes of the comparison of the 2 RUSF formulations were mean FMDmax%, mean plasma arginine to ornithine ratio and mean plasma arginine to asymmetric-di-methylated-arginine (ADMA) ratio. The primary outcomes of the combined effect of both RUSF interventions were mean height and body mass index for age z-scores with analysis by intention to treat. Trial registration: ISRCTN74331412
Findings: 114/119 children had complete data for all reported endpoints. There was no treatment effect of RUSF-v compared to RUSF-b on the ratio of arginine to ornithine (mean within individual difference -0.09, 95% CI -0.03/0.2, p=0.12), or on FMDmax% (-1.00 95% CI -2.47/0.47, p=0.18) but the arginine:ADMA ratio was significantly increased (-0.56, 95% CI -0.81/-0.31, P<0.001). In planned analyses using random effects models to estimate the effect of each intervention compared to baseline/washout, the arginine:ADMA ratio increased following both RUSF-v or RUSF-b (+86%, p<0.001; +41%, p<0.001). Similarly, FMDmax% was higher after
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RUSF-v (+0.92, p<0.001) but not after RUSF-b intervention (+0.39, p=0.22). Adjusted for covariates, effect estimates for FMDmax% increased: RUSF-v (+1.19, p<0.001) and RUSF-b (+0.93, p=0.008). Following either intervention (RUSF-b and RUSF-v pooled) compared to baseline/wash-outs, body-mass-index-z-score (+0.091, P=0.001) and height-for-age-z-score (+0.013, P=0.081) increased. There were 71 and 81 adverse events of which 21 and 26 were serious during intervention and washout (P=0.31) in 83 participants, 1 of whom died in the 2nd washout period.
Interpretation: RUSF providing 500kcal/day results in small weight gains in children with sickle cell disease. However, RUSF even without arginine and citrulline fortification improves arginine dysregulation and may improve endothelial function. Long-term studies are required to assess if these physiological effects translate to improved clinical outcomes and better growth and development in sickle cell disease
Association between retinal vein occlusion, axial length and vitreous chamber depth measured by optical low coherence reflectometry.
BACKGROUND: Results of ocular biometric measurements in retinal vein occlusion (RVO) eyes are still inconclusive and controversial. The aim of this study was to evaluate the association between ocular axial length (AL), vitreous chamber depth (VCD) and both central (CRVO) and branch retinal vein occlusions (BRVO) using optical low coherence reflectometry (OLCR). METHODS: Both eyes of 37 patients with unilateral CRVO (mean age: 66 +/- 14 years, male:female - 21:16) and 46 patients with unilateral BRVO (mean age: 63 +/- 12 years, male:female - 24:22) were enrolled in this study. The control group consisted of randomly selected single eyes of 67 age and gender matched volunteers without the presence or history of RVO (mean age: 64 +/- 14 years, male:female - 34:33). Optical biometry was performed by OLCR biometer (LenStar LS 900). Average keratometry readings, central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), AL and VCD of eyes with RVO were compared with those of fellow eyes using paired t-tests and with those of control eyes using independent t-tests. RESULTS: Mean CCT, ACD and LT, average keratometry readings of affected RVO eyes, unaffected fellow eyes and control eyes was not statistically different in either groups. In eyes with CRVO mean AL and VCD of affected eyes were significantly shorter than those of control eyes (p < 0.001, p < 0.05), mean difference in AL and VCD between the affected and control eyes was 0.56 +/- 0.15 mm and 0.45 +/- 0.19 mm, respectively. In eyes with BRVO, mean AL of the affected eyes was significantly shorter with a mean difference of 0.57 +/- 0.15 mm (p < 0.001) and the VCD was significantly shorter with a mean difference of 0.61 +/- 0.15 mm (p < 0.001) comparing with the control eyes. CONCLUSION: Shorter AL and VCD might be a potential anatomical predisposing factor for development either of CRVO or BRVO
Stepped-wedge randomised trial of laparoscopic ventral mesh rectopexy in adults with chronic constipation: Study protocol for a randomized controlled trial
BACKGROUND: Laparoscopic ventral mesh rectopexy (LVMR) is an established treatment for external full-thickness rectal prolapse. However, its clinical efficacy in patients with internal prolapse is uncertain due to the lack of high-quality evidence. METHODS: An individual level, stepped-wedge randomised trial has been designed to allow observer-blinded data comparisons between patients awaiting LVMR with those who have undergone surgery. Adults with symptomatic internal rectal prolapse, unresponsive to prior conservative management, will be eligible to participate. They will be randomised to three arms with different delays before surgery (0, 12 and 24 weeks). Efficacy outcome data will be collected at equally stepped time points (12, 24, 36 and 48 weeks). The primary objective is to determine clinical efficacy of LVMR compared to controls with reduction in the Patient Assessment of Constipation Quality of Life (PAC-QOL) at 24 weeks serving as the primary outcome. Secondary objectives are to determine: (1) the clinical effectiveness of LVMR to 48 weeks to a maximum of 72 weeks; (2) pre-operative determinants of outcome; (3) relevant health economics for LVMR; (4) qualitative evaluation of patient and health professional experience of LVMR and (5) 30-day morbidity and mortality rates. DISCUSSION: An individual-level, stepped-wedge, randomised trial serves the purpose of providing an untreated comparison for the active treatment group, while at the same time allowing the waiting-listed participants an opportunity to obtain the intervention at a later date. In keeping with the basic ethical tenets of this design, the average waiting time for LVMR (12 weeks) will be shorter than that for routine services (24 weeks)
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