Surface treatment of a polypropylene film with a nitrogen DBD at medium pressure

Surface treatment of polymer films is usually necessary to improve surface wetting and adhesion characteristics. Traditional liquid chemical processes have several disadvantages in contrast to dry finishing processes, like plasma technology. Dielectric barrier discharges at atmospheric pressure are extensively studied for surface treatment, however, almost no research has been done on surface treatment with a dielectric barrier discharge at medium pressure. Therefore, in this paper, a polypropylene (PP) film is plasma-treated with a dielectric barrier discharge (DBD) in nitrogen at medium pressure (5.0 kPa). The surface properties of the plasma-treated samples are examined using contact angle measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Results show that the surface wettability is significantly enhanced after plasma treatment. The incorporation of nitrogen on the surface is significant (10 at%), demonstrating the ability of the used DBD set-up to generate nitrogen-containing functional groups on the PP surface. Nevertheless, a considerable amount of oxygen (10 at%) is incorporated onto the PP surface underlining the extreme reactivity of oxygen active species and the difficulty in overcoming the air contamination problem. Moreover, AFM analysis reveals that the nitrogen plasma creates large changes in the surface morphology of the PP film due to the selective etching of the amorphous regions of the polymer film

Magnetoelastic polarons in the hole-doped quasi-one dimensional model system Y2-xCaxBaNiO5

October 4th, 2004Charge transport in the hole-doped quasi-1D model system Y$_{2-x}$Ca$_x$BaNiO$_5$ (x $\\leq$ 0.15) is investigated in the 50-300 K temperature range. The resistivity temperature dependence is characterized by a constant activation energy $E_{a}/k_{B}\\sim$ 1830 K at room temperature while $E_{a}$ decreases upon cooling. We suggest that $E_{a}$ measures the binding energy of the doped holes which form magneto-acoustic polarons when polarizing the neighboring Ni spins. A semi-classical model is proposed which allows to relate the electrical measurements and the bulk magnetic susceptibility. This model gives a picture of the spin-charge-lattice relation in this inhomogeneously doped quasi-1D system and explains its unusual one-particle charge excitation spectrum close to the Fermi level

Magnetoelastic polarons in the hole-doped quasi-one dimensional model system Y2-xCaxBaNiO5

Charge transport in the hole-doped quasi-1D model system Y$_{2-x}$Ca$_x$BaNiO$_5$ (x $leq$ 0.15) is investigated in the 50-300 K temperature range. The resistivity temperature dependence is characterized by a constant activation energy $E_{a}/k_{B} sim$ 1830 K at room temperature while $E_{a}$ decreases upon cooling. We suggest that $E_{a}$ measures the binding energy of the doped holes which form magneto-acoustic polarons when polarizing the neighboring Ni spins. A semi-classical model is proposed which allows to relate the electrical measurements and the bulk magnetic susceptibility. This model gives a picture of the spin-charge-lattice relation in this inhomogeneously doped quasi-1D system and explains its unusual one-particle charge excitation spectrum close to the Fermi level.Comment: October 4th, 200

Magnetic structure and ferroelectric polarization of MnWO4 investigated by density functional calculations and classical spin analysis

The ordered magnetic states of MnWO4 at low temperatures were examined by evaluating the spin exchange interactions between the Mn2+ ions of MnWO4 on the basis of first principles density functional calculations and by performing classical spin analysis with the resulting spin exchange parameters. Our work shows that the spin exchange interactions are frustrated within each zigzag chain of Mn2+ ions along the c-direction and between such chains of Mn2+ ions along the a-direction. This explains the occurrence of a spiral-spin order along the c- and a-directions in the incommensurate magnetic state AF2, and that of a uudd spin order along the c- and a-directions in the commensurate magnetic state AF1. The ferroelectric polarization of MnWO4 in the spiral-spin state AF2 was examined by performing Berry phase calculations for a model superstructure to find that the ferroelectric polarization occurs along the b-direction, in agreement with experiment.Comment: 30 pages, 10 figures, 4 figure

Cardiac troponin and skeletal muscle oxygenation in severe post-partum haemorrhage

International audienceIntroductionCardiac troponin has been shown to be elevated in one-half of the parturients admitted for post-partum haemorrhage. The purpose of the study was to assess whether increased cardiac troponin was associated with a simultaneous alteration in haemoglobin tissue oxygen saturation in peripheral muscles in post-partum haemorrhage.MethodsTissue haemoglobin oxygen saturation of thenar eminence muscle (StO2) was measured via near-infrared spectroscopy technology. Two sets of StO2 parameters (both isolated baseline and during forearm ischaemia-reperfusion tests) were collected at two time points: upon intensive care unit admission and prior to intensive care unit discharge. Comparisons were performed using Wilcoxon paired tests, and univariate associations were assessed using logistic regression model and Wald tests.ResultsThe 42 studied parturients, admitted for post-partum haemorrhage, had clinical and biological signs of severe blood loss. Initial cardiac troponin I was increased in 24/42 parturients (0.43 ± 0.60 μrg/l). All measured parameters of muscular haemoglobin oxygen saturation, including Srecovery, were also altered at admission and improved together with improved haemodynamics, when bleeding was controlled. Multivariate analysis showed that muscular Srecovery ConclusionsOur study confirmed the high incidence of increased cardiac troponin, and demonstrated the simultaneous impairment in the reserve of oxygen delivery to peripheral muscles in parturients admitted for severe post-partum haemorrhage

Human Septic Myopathy: Induction of Cyclooxygenase, Heme Oxygenase and Activation of the Ubiquitin Proteolytic Pathway

Background: Skeletal muscle failure and wasting are manifestations of sepsis in humans that leads to serious and prolonged complications. The authors investigated the role of the major proinflammatory and antiinflammatory pathways, namely the inducible isoforms cyclooxygenase (COX-2) and heme oxygenase (HO-1), and the ubiquitin proteolytic pathway in skeletal muscle of septic patients. Methods: Protein expression was detected by Western blot techniques. Muscle biopsies were taken from two muscle groups, rectus abdominis and vastus lateralis, of septic and control patients. Results: The study showed an increase in COX-2 and HO-1 proteins expression and an activation of the proteolytic ubiquitin pathway with a parallel increase in free ubiquitin and ubiquitinated proteins in skeletal muscle of septic but not of control patients. In addition, those patients who would die from septic shock expressed more COX-2 and HO-1 proteins in muscle biopsies than did those patients who would survive. Conclusions: This study showed a marked involvement of local proinflammatory and antiinflammatory pathways and, more importantly, demonstrated the existence of an active ubiquitin proteolytic pathway in skeletal muscle of septic patients. Activation of ubiquitin pathway could be involved in sepsis-related muscle catabolism and wasting

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Comportements de la chaine antiferromagnetique: etude du systeme AgCrP_2S_6(S=1)-AgCrP_2S_6(S)3/2)

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 82729 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc