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41.
Effects of Aluminium Contamination on the Nervous System of Freshwater Aquatic Vertebrates: A Review
Marie Closset Katia Cailliau Sylvain Slaby Matthieu Marin 《International journal of molecular sciences》2022,23(1)
Aluminium (Al) is the most common natural metallic element in the Earth’s crust. It is released into the environment through natural processes and human activities and accumulates in aquatic environments. This review compiles scientific data on the neurotoxicity of aluminium contamination on the nervous system of aquatic organisms. More precisely, it helps identify biomarkers of aluminium exposure for aquatic environment biomonitoring in freshwater aquatic vertebrates. Al is neurotoxic and accumulates in the nervous system of aquatic vertebrates, which is why it could be responsible for oxidative stress. In addition, it activates and inhibits antioxidant enzymes and leads to changes in acetylcholinesterase activity, neurotransmitter levels, and in the expression of several neural genes and nerve cell components. It also causes histological changes in nerve tissue, modifications of organism behaviour, and cognitive deficit. However, impacts of aluminium exposure on the early stages of aquatic vertebrate development are poorly described. Lastly, this review also poses the question of how accurate aquatic vertebrates (fishes and amphibians) could be used as model organisms to complement biological data relating to the developmental aspect. This “challenge” is very relevant since freshwater pollution with heavy metals has increased in the last few decades. 相似文献
42.
Lauralie Mangeot-Peter Sylvain Legay Jean-Francois Hausman Sergio Esposito Gea Guerriero 《International journal of molecular sciences》2016,17(9)
Gene expression profiling via quantitative real-time PCR is a robust technique widely used in the life sciences to compare gene expression patterns in, e.g., different tissues, growth conditions, or after specific treatments. In the field of plant science, real-time PCR is the gold standard to study the dynamics of gene expression and is used to validate the results generated with high throughput techniques, e.g., RNA-Seq. An accurate relative quantification of gene expression relies on the identification of appropriate reference genes, that need to be determined for each experimental set-up used and plant tissue studied. Here, we identify suitable reference genes for expression profiling in stems of textile hemp (Cannabis sativa L.), whose tissues (isolated bast fibres and core) are characterized by remarkable differences in cell wall composition. We additionally validate the reference genes by analysing the expression of putative candidates involved in the non-oxidative phase of the pentose phosphate pathway and in the first step of the shikimate pathway. The goal is to describe the possible regulation pattern of some genes involved in the provision of the precursors needed for lignin biosynthesis in the different hemp stem tissues. The results here shown are useful to design future studies focused on gene expression analyses in hemp. 相似文献
43.
The character of the chemical bond between stabilizers and isocyanates used to cure the HTPB binder was determined. The aim was to explain, why it is not possible to extract some stabilizers from the binder of rocket motors. Investigations were performed by 1H‐NMR‐spectroscopy on various combinations of stabilizers and isocyanates used to cure HTPB. It was demonstrated that stabilizes of some type can be attached to the polymeric network via a reaction with the di‐isocyanate. Criteria to evaluate the possibility of bonding the stabilizer to the network are derived. Finally the implication of the chemical bonding on the stabilizing effect is discussed. 相似文献
44.
Nitrogen-doped carbon nanotubes (CNx-NTs) were prepared using a floating catalyst chemical vapor deposition method. Melamine precursor was employed to effectively control nitrogen content within the CNx-NTs and modulate their structure. X-ray photoelectron spectroscopy (XPS) analysis of the nitrogen bonding demonstrates the nitrogen-incorporation profile according to the precursor amount, which indicates the correlation between the nitrogen concentration and morphology of nanotubes. With the increase of melamine amount, the growth rate of nanotubes increases significantly, and the inner structure of CNx-NTs displayed a regular morphology transition from straight and smooth walls (0 at.% nitrogen) to cone-stacked shapes or bamboo-like structure (1.5%), then to corrugated structures (3.1% and above). Both XPS and CHN group results indicate that the nitrogen concentration of CNx-NTs remained almost constant even after exposing them to air for 5 months, revealing superior nitrogen stability in CNTs. Raman analysis shows that the intensity ratio of D to G bands (ID/IG) of nanotubes increases with the melamine amount and position of G-band undergoes a down-shift due to increasing nitrogen doping. The aligned CNx-NTs with modulated morphology, controlled nitrogen concentration and superior stability may find potential applications in developing various nanodevices such as fuel cells and nanoenergetic functional components. 相似文献
45.
46.
We present a manufacturing method based on the dynamic use of phase plates to photowrite Bragg gratings. This process allows for control of the local value of the index modulation envelope in the grating. The application to apodized fiber Bragg gratings is discussed. 相似文献
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48.
Sylvain Paris François X. Sillion Long Quan 《International Journal of Computer Vision》2006,66(2):141-161
Surface reconstruction from multiple calibrated images has been mainly approached using local methods, either as a continuous
optimization problem driven by level sets, or by discrete volumetric methods such as space carving. We propose a direct surface
reconstruction approach which starts from a continuous geometric functional that is minimized up to a discretization by a
global graph-cut algorithm operating on a 3D embedded graph. The method is related to the stereo disparity computation based
on graph-cut formulation, but fundamentally different in two aspects. First, existing stereo disparity methods are only interested
in obtaining layers of constant disparity, while we focus on high resolution surface geometry. Second, most of the existing
graph-cut algorithms only reach approximate solutions, while we guarantee a global minimum. The whole procedure is consistently
incorporated into a voxel representation that handles both occlusions and discontinuities. We demonstrate our algorithm on
real sequences, yielding remarkably detailed surface geometry up to 1/10th of a pixel.
Author has worked on this project during his Ph. D. at ARTIS 相似文献
49.
Sylvain Pradalier Catuscia Palamidessi 《Electronic Notes in Theoretical Computer Science》2006,164(3):119
In this work we propose a probabilistic extension of the π-calculus. The main novelty is a probabilistic mixed choice operator, that is, a choice construct with a probability distribution on the branches, and where input and output actions can both occur as guards. We develop the operational semantics of this calculus, and then we investigate its expressiveness. In particular, we compare it with the sublanguage with the two separate choices, where input and output guards are not allowed together in the same choice construct. Our main result is that the separate choices can encode the mixed one. Further, we show that input-guarded choice can encode output-guarded choice and viceversa. In contrast, we conjecture that neither of them can encode the pair of the two separate choices. 相似文献
50.
Roger Moret Pascale Launois Sylvain Ravy 《Fullerenes, Nanotubes and Carbon Nanostructures》1996,4(6):1287-1298
Single-crystal X-ray diffraction studies of the orientational ordering in solid C60 are reviewed. The temperature dependence of selected Bragg reflections was carefully examined, allowing to obtain original information on the first-order orientational ordering transition at To = 259K, the unusual behavior of both fundamental and superstructure reflections below To and the freezing in of the C60 reorientations at Tg ≈ 85K. The diffuse intensity due to orientational disorder of the C60 molecules at room temperature is found to be strongly modulated, both radially and azimuthally. showing that the molecular orientations are indeed correlated. The corresponding intensity distribution has been calculated within a mean-field theory for different microscopic models of inter molecular interactions. It should allow a better understanding of these interactions. 相似文献