88 research outputs found
Genotoxicity of DrinkingWater Disinfectants in Plant Bioassays
The genotoxicity of two widely used drinking
water disinfectants, sodium hypochlorite (NaClO)
and chlorine dioxide (ClO2), and a new disinfectant,
peracetic acid (PAA, CH3-CO-COOH), was
evaluated in three short-term plant tests: (1) induction
of anaphase chromosome aberrations in the
root cells of Allium cepa, (2) micronucleus induction
in the root cells of Vicia faba, and (3) micronucleus
induction in Tradescantia pollen cells. The
study was carried out in the laboratory by directly
exposing the plants to several concentrations of
the disinfectants in redistilled water at unadjusted
(acid) and adjusted (neutral) pHs. Both 0.1 and
0.2 mg/l NaClO induced chromosome aberrations
in the Allium cepa test at acid pH, but concentrations
up to 0.5 mg/l of all the disinfectants
were negative at neutral pH. Concentrations ranging
from 0.1 to 0.5 mg/l NaClO, ClO2, and PAA
induced micronuclei in Vicia faba at acid pH,
while 1â2 mg/l NaClO and ClO2 and 0.5â2
mg/l PAA gave positive responses at neutral pH.
Most of concentrations of ClO2 produced positive
responses in the Tradescantia micronucleus test. In
general, the highest levels of genotoxicity were
observed under acid conditions; at acid pH,
significant effects were induced by low concentrations
of ClO2 and PAA. Since the test concentrations
of disinfectants are typical of those
encountered in the biocidal treatment of tap
water and similar concentrations are consumed
daily by a large number of people, the genotoxicity
of these compounds may constitute a significant
public health concern
A 1-D PLANAR SOLID OXIDE FUEL CELL MODEL FOR SIMULATION OF SOFC-BASED ENERGY SYSTEMS
ABSTRACT A one-dimensional steady-state model for planar solid oxide fuel cells (SOFCs) is presented. Appropriately simplified, the model includes sufficient detail for supporting ongoing investigations involving the simulation of SOFC-based advanced energy systems. The presentation focuses on a set of nonlinear equations accounting for conservation of mass and energy along a single SOFC in a co-flow configuration. Electrochemical models also are employed, including one previously used for a zero dimensional approach. The equations are described through a phenomenological approach based on the best recent work in the field and model validation is carried out in two distinct phases using previously published information. Potential areas of application for the model presented are noted. INTRODUCTION The objective of this paper is to report on work in progress aimed at simulating advanced energy systems having a solid oxide fuel cell as a principal component. For such work it is sufficient to employ a simplified SOFC model that captures the salient physical/chemical effects. Accordingly, efforts thus far have centered on the development of a one-dimensional SOFC model resting solidly on the best recent work in the field, while being convenient and effective for achieving the larger goal of simulating SOFC-based advanced energy systems. The intent of this modeling effort is to be able to handle both the hydrogen and internal reforming cases, while representing the electrochemistry using either a grey box approach or black box approach. Specifically in this paper, a 1-D model has been developed that captures the dominant physical and electrochemical phenomena taking place in a co-flow planar SOFC, accounting for internal reforming while retaining computational simplicity and good accuracy. The objective of the model is to simulat
Quantitative value of aldosterone-renin ratio for detection of aldosterone-producing adenoma: The Aldosterone-Renin Ratio for Primary Aldosteronism (AQUARR) study
Background Current guidelines recommend use of the aldosterone\u2010renin ratio (ARR) for the case detection of primary aldosteronism followed by confirmatory tests to exclude false\u2010positive results from further diagnostic workup. We investigated the hypothesis that this could be unnecessary in patients with a high ARR value if the quantitative information carried by the ARR is taken into due consideration.
Methods and Results We interrogated 2 large data sets of prospectively collected patients studied with the same predefined protocol, which included the captopril challenge test. We used an unambiguous diagnosis of aldosterone\u2010producing adenoma as reference index. We also assessed whether the post\u2010captopril ARR and plasma aldosterone concentration fall furnished a diagnostic gain over baseline ARR values. We found that the false\u2010positive rate fell exponentially, and, conversely, the specificity increased with rising ARR values. At receiver operating characteristics curves and diagnostic odds ratio analysis, the high baseline ARR values implied very high positive likelihood ratio and diagnostic odds ratio values. The baseline and post\u2010captopril ARR showed similar diagnostic accuracy (area under the receiver operating characteristics curve) in both the exploratory and validation cohorts, indicating lack of diagnostic gain with this confirmatory test (between\u2010area under the curve difference, 0.005; 95% CI, 120.031 to 0.040; P=0.7 for comparison, and 0.05; 95% CI, 120.061 to 0.064; P=0.051 for comparison, respectively).
Conclusions These results indicate that the ARR conveys key quantitative information that, if properly used, can simplify the diagnostic workup, resulting in saving of money and resources. This can offer the chance of diagnosis and ensuing adrenalectomy to a larger number of hypertensive patients, ultimately resulting in better control of blood pressure
Adherence to antibiotic treatment guidelines and outcomes in the hospitalized elderly with different types of pneumonia
Background: Few studies evaluated the clinical outcomes of Community Acquired Pneumonia (CAP), Hospital-Acquired Pneumonia (HAP) and Health Care-Associated Pneumonia (HCAP) in relation to the adherence of antibiotic treatment to the guidelines of the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) in hospitalized elderly people (65 years or older). Methods: Data were obtained from REPOSI, a prospective registry held in 87 Italian internal medicine and geriatric wards. Patients with a diagnosis of pneumonia (ICD-9 480-487) or prescribed with an antibiotic for pneumonia as indication were selected. The empirical antibiotic regimen was defined to be adherent to guidelines if concordant with the treatment regimens recommended by IDSA/ATS for CAP, HAP, and HCAP. Outcomes were assessed by logistic regression models. Results: A diagnosis of pneumonia was made in 317 patients. Only 38.8% of them received an empirical antibiotic regimen that was adherent to guidelines. However, no significant association was found between adherence to guidelines and outcomes. Having HAP, older age, and higher CIRS severity index were the main factors associated with in-hospital mortality. Conclusions: The adherence to antibiotic treatment guidelines was poor, particularly for HAP and HCAP, suggesting the need for more adherence to the optimal management of antibiotics in the elderly with pneumonia
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
Non disjunction rates of mouse chromosomes involved in heterozygous Rb rearrangements measured by chromosome painting of spermatocytes. II. The effects of trivalent combinations and genetic background
Chromosome specific nondisjunction rates were quantified by dual-colour FISH in spermatocytes II of Robertsonian heterozygous mice with different trivalent combinations or, alternatively, with different genetic backgrounds. We found that such factors do not influence the proneness to nondisjunction of specific chromosomes
New Methods to Study the Microcirculation
Essential hypertension is associated with structural alterations in the microvessels; in particular, an increase in the media thickness to internal lumen ratio of small resistance arteries (MLR) and a reduction in capillary density have been observed. The evaluation of the morphological characteristics of small resistance arteries in humans is challenging. The gold-standard method is generally considered to be the measurement by wire or pressure micromyography of MLR of subcutaneous small vessels obtained by local biopsies. However, noninvasive techniques for the evaluation of retinal arterioles were recently proposed; in particular, 2 approaches, scanning laser Doppler flowmetry (SLDF) and adaptive optics (AO), seem to provide useful information. Both of them provide an estimation of the wall to lumen ratio (WLR) of retinal arterioles. Moreover, a noninvasive measurement of basal and total capillary density may be obtained by videomicroscopy/capillaroscopy. It has been recently demonstrated that AO has a substantial advantage over SLDF in terms of evaluation of microvascular morphology, since WLR measured with AO is more closely correlated with the M/L of subcutaneous small arteries. The possibility to noninvasively assess in a reliable way, microvascular morphology in a clinical setting may represent a major advancement, since micromyography has substantial limitations in its application due to the local invasiveness of the procedure
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