125 research outputs found
High molecular weight polystyrene particles by cationic miniemulsion polymerization catalyzed by an iron-containing imidazolium-based ionic liquid
Cationic styrene polymerizations in aqueous media were conducted using the miniemulsion polymerization technique with the ionic liquid 1-N-butyl-3-N-methylimidazolium heptachloro diferrate (BMI.Fe2Cl7) as catalyst, hexadecyltrimethylammonium bromide (CTAB) as surfactant and hexadecane as costabilizer. The ionic liquid
was effective to initiate styrene miniemulsion polymerization at a BMI.Fe2Cl7:styrene molar ratios as low as 1:1000. Increasing the reaction temperature from 70 °C to 90 °C led to an increase in both, conversion and molecular weight. And polystyrene with much higher molecular weight (viscosity average molecular weights of up to 2231 kDa) than those usually obtained in cationic polymerizations was produced. Furthermore, while particle sizes remained almost constant around 150 nm during polymerizations, an almost linear increase of conversion with reaction time was observed. In addition, molecular weight increased steadily with conversion approaching the behavior of living cationic polymerization.
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Nerve Agent Hydrolysis Activity Designed into a Human Drug Metabolism Enzyme
Organophosphorus (OP) nerve agents are potent suicide inhibitors of the essential neurotransmitter-regulating enzyme acetylcholinesterase. Due to their acute toxicity, there is significant interest in developing effective countermeasures to OP poisoning. Here we impart nerve agent hydrolysis activity into the human drug metabolism enzyme carboxylesterase 1. Using crystal structures of the target enzyme in complex with nerve agent as a guide, a pair of histidine and glutamic acid residues were designed proximal to the enzyme's native catalytic triad. The resultant variant protein demonstrated significantly increased rates of reactivation following exposure to sarin, soman, and cyclosarin. Importantly, the addition of these residues did not alter the high affinity binding of nerve agents to this protein. Thus, using two amino acid substitutions, a novel enzyme was created that efficiently converted a group of hemisubstrates, compounds that can start but not complete a reaction cycle, into bona fide substrates. Such approaches may lead to novel countermeasures for nerve agent poisoning
Antiproliferative activity of synthetic fatty acid amides from renewable resources
AbstractIn the work, the in vitro antiproliferative activity of a series of synthetic fatty acid amides were investigated in seven cancer cell lines. The study revealed that most of the compounds showed antiproliferative activity against tested tumor cell lines, mainly on human glioma cells (U251) and human ovarian cancer cells with a multiple drug-resistant phenotype (NCI-ADR/RES). In addition, the fatty methyl benzylamide derived from ricinoleic acid (with the fatty acid obtained from castor oil, a renewable resource) showed a high selectivity with potent growth inhibition and cell death for the glioma cell lineâthe most aggressive CNS cancer
Physical training improves physical activity levels but is associated with amplification of sedentary behavior in older women
Physical activity level (PAL) and sedentary behavior (SB) are independent predictors of mortality. It is unclear how these predictors interact with each other and health variables. Investigate the bidirectional relationship between PAL and SB, and their impact and health variables of women aged 60 to 70 years. One hundred forty-two older adults women (66.3â±â2.9 years) considered insufficiently active were submitted to 14 weeks of multicomponent training (MT), multicomponent training with flexibility (TMF), or the control group (CG). PAL variables were analyzed by accelerometry and QBMI questionnaire, physical activity (PA) light, moderate, vigorous and CS by accelerometry, 6âmin walk (CAM), SBP, BMI, LDL, HDL, uric acid, triglycerides, glucose and cholesterol total. In linear regressions, CS was associated with glucose (B:12.80; CI:9.31/20.50; pâ<â0.001; R2:0.45), light PA (B:3.10; CI:2, 41/4.76; pâ<â0.001; R2:0.57), NAF by accelerometer (B:8.21; CI:6.74/10.02; pâ<â0.001; R2:0.62), vigorous PA (B:794.03; CI:682.11/908.2; pâ<â0.001; R2:0.70), LDL (B:13.28; CI:7.45/16.75; pâ<â0.002; R2:0.71) and 6âmin walk (B:3.39; CI:2.96/8.75; pâ<â0.004; R2:0.73). NAF was associated with mild PA (B:0.246; CI:0.130/0.275; pâ<â0.001; R2:0.624), moderate PA (B:0.763; CI:0.567/0.924; pâ<â0.001; R2:0.745), glucose (B:â0.437; CI:â0.789/â0.124; pâ<â0.001; R2:0.782), CAM (B:2.223; CI:1.872/4.985; pâ<â0.002; R2:0.989) and CS (B:0.253; CI: 0.189/0.512; pâ<â0.001; R2:1.94). The NAF can enhance CS. Build a new look at how these variables are independent but dependent simultaneously, being able to influence the quality of health when this dependence is denied
PolĂtica Nacional de SaĂșde Integral da População Negra: implementação, conhecimento e aspectos socioeconĂŽmicos sob a perspectiva desse segmento populacional
A PolĂtica Nacional de SaĂșde Integral da População Negra tem o objetivo de garantir a equidade na atenção Ă saĂșde para esse segmento populacional. Tal medida possui um carĂĄter compensatĂłrio em virtude das discriminaçÔes raciais existentes ao longo da histĂłria do Brasil. A população negra apresenta maior vulnerabilidade social e econĂŽmica, o que reflete uma menor expectativa de vida e maior susceptibilidade a agravos. O objetivo do estudo Ă© investigar o conhecimento da população negra acerca da polĂtica, seus potenciais benefĂcios e as dificuldades de acesso Ă saĂșde. Trata-se de uma pesquisa transversal, descritiva e quantitativa. Foram realizadas entrevistas estruturadas com 391 indivĂduos negros, usuĂĄrios do SUS, da cidade de Juiz de Fora. A amostra foi estratificada de acordo com raça (preto e pardo), renda e escolaridade. Cerca de 90% dos entrevistados relataram desconhecer a existĂȘncia de uma polĂtica de saĂșde para a população negra e 53% declararam uma possĂvel discriminação racial. Observou-se tambĂ©m associação positiva entre discriminação e menor escolaridade e renda. Apesar de desconhecerem a existĂȘncia da PNSIPN, a maioria dos entrevistados aprovou seus objetivos, mesmo relatando a possibilidade de discriminação dela advinda
Impact of renal impairment on atrial fibrillation: ESC-EHRA EORP-AF Long-Term General Registry
Background: Atrial fibrillation (AF) and renal impairment share a bidirectional relationship with important pathophysiological interactions. We evaluated the impact of renal impairment in a contemporary cohort of patients with AF. Methods: We utilised the ESC-EHRA EORP-AF Long-Term General Registry. Outcomes were analysed according to renal function by CKD-EPI equation. The primary endpoint was a composite of thromboembolism, major bleeding, acute coronary syndrome and all-cause death. Secondary endpoints were each of these separately including ischaemic stroke, haemorrhagic event, intracranial haemorrhage, cardiovascular death and hospital admission. Results: A total of 9306 patients were included. The distribution of patients with no, mild, moderate and severe renal impairment at baseline were 16.9%, 49.3%, 30% and 3.8%, respectively. AF patients with impaired renal function were older, more likely to be females, had worse cardiac imaging parameters and multiple comorbidities. Among patients with an indication for anticoagulation, prescription of these agents was reduced in those with severe renal impairment, p <.001. Over 24 months, impaired renal function was associated with significantly greater incidence of the primary composite outcome and all secondary outcomes. Multivariable Cox regression analysis demonstrated an inverse relationship between eGFR and the primary outcome (HR 1.07 [95% CI, 1.01â1.14] per 10 ml/min/1.73 m2 decrease), that was most notable in patients with eGFR <30 ml/min/1.73 m2 (HR 2.21 [95% CI, 1.23â3.99] compared to eGFR â„90 ml/min/1.73 m2). Conclusion: A significant proportion of patients with AF suffer from concomitant renal impairment which impacts their overall management. Furthermore, renal impairment is an independent predictor of major adverse events including thromboembolism, major bleeding, acute coronary syndrome and all-cause death in patients with AF
Clinical complexity and impact of the ABC (Atrial fibrillation Better Care) pathway in patients with atrial fibrillation: a report from the ESC-EHRA EURObservational Research Programme in AF General Long-Term Registry
Background: Clinical complexity is increasingly prevalent among patients with atrial fibrillation (AF). The âAtrial fibrillation Better Careâ (ABC) pathway approach has been proposed to streamline a more holistic and integrated approach to AF care; however, there are limited data on its usefulness among clinically complex patients. We aim to determine the impact of ABC pathway in a contemporary cohort of clinically complex AF patients. Methods: From the ESC-EHRA EORP-AF General Long-Term Registry, we analysed clinically complex AF patients, defined as the presence of frailty, multimorbidity and/or polypharmacy. A K-medoids cluster analysis was performed to identify different groups of clinical complexity. The impact of an ABC-adherent approach on major outcomes was analysed through Cox-regression analyses and delay of event (DoE) analyses. Results: Among 9966 AF patients included, 8289 (83.1%) were clinically complex. Adherence to the ABC pathway in the clinically complex group reduced the risk of all-cause death (adjusted HR [aHR]: 0.72, 95%CI 0.58â0.91), major adverse cardiovascular events (MACEs; aHR: 0.68, 95%CI 0.52â0.87) and composite outcome (aHR: 0.70, 95%CI: 0.58â0.85). Adherence to the ABC pathway was associated with a significant reduction in the risk of death (aHR: 0.74, 95%CI 0.56â0.98) and composite outcome (aHR: 0.76, 95%CI 0.60â0.96) also in the high-complexity cluster; similar trends were observed for MACEs. In DoE analyses, an ABC-adherent approach resulted in significant gains in event-free survival for all the outcomes investigated in clinically complex patients. Based on absolute risk reduction at 1 year of follow-up, the number needed to treat for ABC pathway adherence was 24 for all-cause death, 31 for MACEs and 20 for the composite outcome. Conclusions: An ABC-adherent approach reduces the risk of major outcomes in clinically complex AF patients. Ensuring adherence to the ABC pathway is essential to improve clinical outcomes among clinically complex AF patients
Identification and reconstruction of low-energy electrons in the ProtoDUNE-SP detector
Measurements of electrons from interactions are crucial for the Deep
Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as
searches for physics beyond the standard model, supernova neutrino detection,
and solar neutrino measurements. This article describes the selection and
reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector.
ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and
operated at CERN as a charged particle test beam experiment. A sample of
low-energy electrons produced by the decay of cosmic muons is selected with a
purity of 95%. This sample is used to calibrate the low-energy electron energy
scale with two techniques. An electron energy calibration based on a cosmic ray
muon sample uses calibration constants derived from measured and simulated
cosmic ray muon events. Another calibration technique makes use of the
theoretically well-understood Michel electron energy spectrum to convert
reconstructed charge to electron energy. In addition, the effects of detector
response to low-energy electron energy scale and its resolution including
readout electronics threshold effects are quantified. Finally, the relation
between the theoretical and reconstructed low-energy electron energy spectrum
is derived and the energy resolution is characterized. The low-energy electron
selection presented here accounts for about 75% of the total electron deposited
energy. After the addition of lost energy using a Monte Carlo simulation, the
energy resolution improves from about 40% to 25% at 50~MeV. These results are
used to validate the expected capabilities of the DUNE far detector to
reconstruct low-energy electrons.Comment: 19 pages, 10 figure
Impact of cross-section uncertainties on supernova neutrino spectral parameter fitting in the Deep Underground Neutrino Experiment
A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is
to measure the MeV neutrinos produced by a Galactic
core-collapse supernova if one should occur during the lifetime of the
experiment. The liquid-argon-based detectors planned for DUNE are expected to
be uniquely sensitive to the component of the supernova flux, enabling
a wide variety of physics and astrophysics measurements. A key requirement for
a correct interpretation of these measurements is a good understanding of the
energy-dependent total cross section for charged-current
absorption on argon. In the context of a simulated extraction of
supernova spectral parameters from a toy analysis, we investigate the
impact of modeling uncertainties on DUNE's supernova neutrino
physics sensitivity for the first time. We find that the currently large
theoretical uncertainties on must be substantially reduced
before the flux parameters can be extracted reliably: in the absence of
external constraints, a measurement of the integrated neutrino luminosity with
less than 10\% bias with DUNE requires to be known to about 5%.
The neutrino spectral shape parameters can be known to better than 10% for a
20% uncertainty on the cross-section scale, although they will be sensitive to
uncertainties on the shape of . A direct measurement of
low-energy -argon scattering would be invaluable for improving the
theoretical precision to the needed level.Comment: 25 pages, 21 figure
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