| 1. |
- Aguer, P, et al.
(författare)
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Skin morphology and layer identification using different STIM geometries
- 2005
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 231:1-4, s. 292-299
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Tidskriftsartikel (refereegranskat)abstract
- The use of on-axis geometry in scanning transmission ion microscopy (STIM) has been widely used for thin biological sample structure identification. In this configuration, the lateral resolution is optimised so that micron or submicron beam spots are easily achieved even for classic microbeam lines. Off-axis STIM was more particularly employed for rapid imaging, and also (when associated to a scattering set-up) for normalising elemental contents obtained by other ion beam analysis techniques in organic thin samples. Due to the very small beam current required, on-axis STIM is a stand-alone technique. Off-axis STIM can be advantageous as it enables the simultaneous utilisation of PIXE and RBS techniques. In this paper, the STIM images obtained with an on-axis geometry, a standard off-axis geometry and a recently developed on-off geometry are presented and discussed. Data from skin samples are used for comparison purposes aiming at studying skin permeability to sunscreens. Skin is a stratified tissue and the precise identification of skin layers is needed to ascertain the penetration depth of the physical filter from the formulation. In addition to the intrinsic difference in image quality due to the beam resolution, the influence of the detector type, implanted silicon detector versus Si pin diode, is discussed on the basis of their energy resolution.. their resistance to beam damage as well as the effect
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| 2. |
- Dussault, C., et al.
(författare)
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Hyperoxia and hypergravity are independent risk factors of atelectasis in healthy sitting humans : a pulmonary ultrasound and SPECT/CT study
- 2016
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Ingår i: Journal of applied physiology. - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 121:1, s. 66-77
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Tidskriftsartikel (refereegranskat)abstract
- Aeroatelectasis has developed in aircrew flying routine peacetime flights on the latest generation high-performance aircraft, when undergoing excessive oxygen supply. To single out the effects of hyperoxia and hypergravity on lung tissue compression, and on ventilation and perfusion, eight subjects were studied before and after 1 h 15 min exposure to +1 to +3.5 G(z) in a human centrifuge. They performed the protocol three times, breathing air, 44.5% O-2, or 100% O-2 and underwent functional and topographical imaging of the whole lung by ultrasound and single-photon emission computed tomography combined with computed tomography (SPECT/CT). Ultrasound lung comets (ULC) and atelectasis both increased after exposure. The number of ULC was <1 pre protocol (i.e., normal lung) and larger post 100% O-2 (22 +/- 3, mean +/- SD) than in all other conditions (P < 0.001). Post 44.5% O-2 differed from air (P < 0.05). Seven subjects showed low-to medium-grade atelectasis post 100% O-2. There was an effect on grade of gas mixture and hypergravity, with interaction (P < 0.001, respectively); 100% O-2, 44.5% O-2, and air differed from each other (P < 0.05). SPECT ventilation and perfusion were always normal. Ultrasound concurred with CT in showing normal lung in the upper third and ULC/atelectasis in posterior and inferior areas, not for other localizations. In conclusion, hyperoxia and hypergravity are independent risk factors of reversible atelectasis formation. Ultrasound is a useful screening tool. Together with electrical impedance tomography measurements (reported separately), these findings show that zones with decreased ventilation prone to transient airway closure are present above atelectatic areas.
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| 3. |
- Lehours, P., et al.
(författare)
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Genome sequencing reveals a phage in Helicobacter pylori
- 2011
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Ingår i: mBio. - 2161-2129 .- 2150-7511. ; 2:6, s. e00239-
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Tidskriftsartikel (refereegranskat)abstract
- Helicobacter pylori chronically infects the gastric mucosa in more than half of the human population; in a subset of this population, its presence is associated with development of severe disease, such as gastric cancer. Genomic analysis of several strains has revealed an extensive H pylori pan-genome, likely to grow as more genomes are sampled. Here we describe the draft genome sequence (63 contigs; 26× mean coverage) of H pylori strain B45, isolated from a patient with gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The major finding was a 24.6-kb prophage integrated in the bacterial genome. The prophage shares most of its genes (22/27) with prophage region II of Helicobacter acinonychis strain Sheeba. After UV treatment of liquid cultures, circular DNA carrying the prophage integrase gene could be detected, and intracellular tailed phage-like particles were observed in H pylori cells by transmission electron microscopy, indicating that phage production can be induced from the prophage. PCR amplification and sequencing of the integrase gene from 341 H pylori strains from different geographic regions revealed a high prevalence of the prophage (21.4%). Phylogenetic reconstruction showed four distinct clusters in the integrase gene, three of which tended to be specific for geographic regions. Our study implies that phages may play important roles in the ecology and evolution of H pylori.
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| 4. |
- Lekki, J., et al.
(författare)
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On the follicular pathway of percutaneous uptake of nanoparticles: Ion microscopy and autoradiography studies
- 2007
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - : Elsevier BV. - 0168-583X. ; 260:1, s. 174-177
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Tidskriftsartikel (refereegranskat)abstract
- We report on the visualization of the penetration of sunscreen formulations containing TiO2 nanoparticles (about 20 nm primary particle size) into hair follicles of both human and porcine skin using the complementary methods of ion microscopy (PIXE, RBS, STIM) and autoradiography. Particles were found as deep as approx. 400 pin in the follicle, obviously introduced mechanically rather than by a diffusive process. No particles were observed in vital tissue nor in sebaceous glands. (c) 2007 Elsevier B.V. All rights reserved.
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| 5. |
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