The demand for skin models as alternatives to animal testing has grown due to ethical concerns and the need for accurate substance evaluation. These alternatives, known as New Approach Methodologies (NAMs), are increasingly used for regulatory decisions. Current skin models from primary human cells often rely on bovine collagen, raising ethical issues.
View Article and Find Full Text PDFAtomic Fe in N-doped C (Fe-N-C) catalysts provide the most promising non-precious metal O reduction activity at the cathodes of proton exchange membrane fuel cells. However, one of the biggest remaining challenges to address towards their implementation in fuel cells is their limited durability. Fe demetallation has been suggested as the primary initial degradation mechanism.
View Article and Find Full Text PDFOrthop Traumatol Surg Res
December 2024
Introduction: Wide Awake Local Anesthesia No Tourniquet (WALANT) technique has been widely used in hand surgery, but there are few prospective data on its use in forefoot surgery.
Hypothesis: The WALANT technique reduces pain compared to general anesthesia for bone surgery on the first ray of forefoot.
Methods: This was a prospective, longitudinal, comparative, non-randomized cohort study in adult patients undergoing bone surgery on the first ray of forefoot.
High theoretical energy density and low cost make lithium-sulfur (LSB) batteries a promising system for next-generation energy storage. LSB performance largely depends on efficient reversible conversion of elemental sulfur to LiS. Here, well-designed sulfur host materials including Fe or Co single atoms embedded on N-doped reduced graphene oxide (MNC/G with M = Fe or Co) are proposed to tackle the LSB challenges and enhance the electrochemical performance.
View Article and Find Full Text PDFOne bottleneck hampering the widespread use of fuel cell vehicles, in particular of proton exchange membrane fuel cells (PEMFCs), is the high cost of the cathode where the oxygen reduction reaction (ORR) occurs, due to the current need of precious metals to catalyze this reaction. Electrochemists tackle this issue in the short/medium term by developing catalysts with improved utilization or efficiency of platinum, and in the longer term, by developing catalysts based on Earth-abundant elements. Considerable progress has been achieved in the initial performance of Metal-nitrogen-carbon (Metal-N-C) catalysts for the ORR, especially with Fe-N-C materials.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
February 2020
Fe-N-C catalysts containing atomic FeN sites are promising candidates as precious-metal-free catalysts for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells. The durability of Fe-N-C catalysts in fuel cells has been extensively studied using accelerated stress tests (AST). Herein we reveal stronger degradation of the Fe-N-C structure and four-times higher ORR activity loss when performing load cycling AST in O - vs.
View Article and Find Full Text PDFThe carbon oxidation reaction (COR) is a critical issue in proton-exchange membrane fuel cells (PEMFCs), as carbon in various forms is the most used electrocatalyst support material. The COR is thermodynamically possible above the C/CO standard potential, but its rate becomes significantly important only at high overpotential (e. g.
View Article and Find Full Text PDFThe oxygen reduction reaction (ORR) is of great interest for future sustainable energy conversion and storage, especially concerning fuel cell applications. The preparation of active, affordable, and scalable electrocatalysts and their application in fuel cell engines of hydrogen cars is a prominent step toward the reduction of air pollution, especially in urban areas. Alloying nanostructured Pt with lanthanides is a promising approach to enhance its catalytic ORR activity, whereby the development of a simple synthetic route turned out to be a nontrivial endeavor.
View Article and Find Full Text PDFThe co-occurrence in the same individual of two numerical chromosomal abnormalities (double aneuploidy) is a very rare condition, especially for autosomes. Clinical presentations are variable depending on the predominating aneuploidy. The authors present a rare case of a male infant with multiple congenital anomalies: craniofacial dysmorphism, short neck, agenesis of the corpus callosum, ventricular septal defect, bilateral broad hallux, large first interdigital space of the toes, plantar furrows, prominent calcaneus and right kidney agenesis.
View Article and Find Full Text PDFTuning the surface structure at the atomic level is of primary importance to simultaneously meet the electrocatalytic performance and stability criteria required for the development of low-temperature proton-exchange membrane fuel cells (PEMFCs). However, transposing the knowledge acquired on extended, model surfaces to practical nanomaterials remains highly challenging. Here, we propose 'surface distortion' as a novel structural descriptor, which is able to reconciliate and unify seemingly opposing notions and contradictory experimental observations in regards to the electrocatalytic oxygen reduction reaction (ORR) reactivity.
View Article and Find Full Text PDFPurpose: To describe the neuromuscular and perceptual responses to incline, decline or level treadmill exercise.
Methods: Fifteen healthy subjects performed on separate days 45 min treadmill exercise at 75% heart rate reserve in a level (+ 1% slope), incline (+ 15%) or decline condition (- 15%). Neuromuscular function of the knee extensors (KE) was assessed before and after exercise.
Due to their interesting electrocatalytic properties for the oxygen reduction reaction (ORR), hollow Pt-alloy nanoparticles (NPs) supported on high-surface-area carbon attract growing interest. However, the suitable synthesis methods and associated mechanisms of formation, the reasons for their enhanced specific activity for the ORR, and the nature of adequate alloying elements and carbon supports for this type of nanocatalysts remain open questions. This Review aims at shedding light on these topics with a special emphasis on hollow PtNi NPs supported onto Vulcan C (PtNi/C).
View Article and Find Full Text PDFThe oxygen reduction reaction (ORR) activity of Pt-alloy electrocatalysts depends on (i) the strain/ligand effects induced by the non-noble metal (3d-transition metal or a rare-earth element) alloyed to Pt, (ii) the orientation of the catalytic surfaces, and (iii) the density of structural defects (SDs) (e.g., vacancies, voids, interconnections).
View Article and Find Full Text PDFDetermining the formation and growth mechanism of bimetallic nanoparticles (NPs) with atomic detail is fundamental to synthesize efficient "catalysts by design". However, an understanding of the elementary steps which take place during their synthesis remains elusive. Herein, we have exploited scanning transmission electron microscopy coupled to energy-dispersive X-ray spectroscopy, operando wide angle and small-angle X-ray scattering, and electrochemistry to unveil the formation and growth mechanism of hollow PtNi/C NPs.
View Article and Find Full Text PDFIntroduction: Knowledge about hypertension might influence blood pressure (BP) control and adherence to treatment.
Aim: This study was conducted in collaboration with 11 pharmacies to assess the level of knowledge about hypertension and BP targets among the hypertensive population in the French region of Alsace.
Methods: Study participants (N = 380) were hypertensive adult patients visiting a pharmacy spontaneously from June to October, 2013, to get their regular prescribed medications including at least one antihypertensive agent.
Following a well-defined series of acid and heat treatments on a benchmark Pt3Co/C sample, three different nanostructures of interest for the electrocatalysis of the oxygen reduction reaction were tailored. These nanostructures could be sorted into the "Pt-skin" structure, made of one pure Pt overlayer, and the "Pt-skeleton" structure, made of 2-3 Pt overlayers surrounding the Pt-Co alloy core. Using a unique combination of high-resolution aberration-corrected STEM-EELS, XRD, EXAFS, and XANES measurements, we provide atomically resolved pictures of these different nanostructures, including measurement of the Pt-shell thickness forming in acidic media and the resulting changes of the bulk and core chemical composition.
View Article and Find Full Text PDFThe study focuses on preparation of thin cerium oxide films with a porous structure prepared by rf magnetron sputtering on a silicon wafer substrate using amorphous carbon (a-C) and nitrogenated amorphous carbon films (CNx) as an interlayer. We show that the structure and morphology of the deposited layers depend on the oxygen concentration in working gas used for cerium oxide deposition. Considerable erosion of the carbonaceous interlayer accompanied by the formation of highly porous carbon/cerium oxide bilayer systems is reported.
View Article and Find Full Text PDFModels of the human respiratory tract developed in the past were based on measurements made on human tracheobronchial airways of healthy subjects. With the exception of a few morphometric characteristics such as the bronchial wall thickness (WT), very little has been published concerning the effects of disease on the tree structure and geometrical features. In this study, a commercial software package was used to segment the airway tree of seven healthy and six moderately persistent asthmatic patients from high resolution computed tomography images.
View Article and Find Full Text PDFThe Maxwell-Bloch code COLAX has been upgraded to use detailed hydrodynamical and collisional-radiative simulations of a soft x-ray laser plasma with traveling-wave pumping. The seeding of short pulses of high-order harmonics of the pump laser into the x-ray laser medium has been simulated. The amplification is shown to be a dynamic, two-stage process: the atomic dipoles of the lasing ions are first coherently excited by the short pulse, and subsequently generate a radiation wake which is amplified along its path through the plasma, with consequences on the experimentally recorded spectra.
View Article and Find Full Text PDFWe present the first direct measurement of the time evolution of the gain of a soft x-ray laser amplifier. The measurement is based on the injection of a seed pulse, obtained by high-order harmonic generation, into an x-ray laser medium. Strong amplification occurs when the seed pulse is synchronized with the gain period.
View Article and Find Full Text PDFPhys Rev E Stat Nonlin Soft Matter Phys
May 2004
We present a modeling study of x-ray line polarization in plasmas driven by high-intensity, ultrashort duration pulsed lasers. Electron kinetics simulations of these transient and nonequilibrium plasmas predict non-Maxwellian and anisotropic electron distribution functions. Under these conditions, the magnetic sublevels within fine structure levels can be unequally populated which leads to the emission of polarized lines.
View Article and Find Full Text PDFA predictive parameter of beta-lactam therapeutic efficacy is the time (T > MIC) while antibiotic serum concentrations are above the MIC of suspected bacteriological agents. This led us to carry out a randomised open study to compare the usually used intermittent administration of Tazocin (three injections of 4 g/0.5 g a day) and continuous perfusion of 12 g/1.
View Article and Find Full Text PDFIn a retrospective study, 2,238 mycologic samples obtained in 1999 from 89 patients hospitalised in an intensive care unit dedicated to digestive diseases were analysed. Feasibility of monitoring fungal colonisation and implications for workload and costs were assessed. From this experience, we confirmed the ability of the Pittet index to identify patients at high risk for Candida infection.
View Article and Find Full Text PDFAnn Fr Anesth Reanim
January 2001
We report the case of a patient who experienced a postoperative Wernicke encephalopathy 8 days after a left hepatectomy performed for metastasis related to a rectal cancer. During the six months before surgery the patient lost 10 kg of weight (15%). Moreover, in the postoperative period the patient received exclusively 5% dextrose solution intravenously.
View Article and Find Full Text PDFGastroenterol Clin Biol
December 1998
We report the unusual case of a patient with chronic carriage of Salmonella typhi who presented with partially calcified splenic abscess linked to colic fistula and ascitis. The colic fistula could be secondary to ischemic necrosis by left colon compression due to spleen large abscess. Fistula was evidenced by abdominal computed tomography scan and confirmed by barium enema.
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