Moderate exercise effects on orthostatic intolerance while wearing protective clothing

INTRODUCTION: Wearing protective clothing can have deleterious effects on operational capacities and can cause non-compensable thermal stress. We studied the effects of moderate exercise on orthostatic tolerance while wearing protective clothing in eight healthy subjects tolerant to orthostatism. METHODS: Subjects performed a 60-min moderate exercise on a treadmill followed by a 45-min head-up tilt test. Subjects performed the moderate exercise either in a comfortable condition (control, CON) or wearing protective clothing (PRO) in a random order. RESULTS: Compared with the CON trial, exercise in the PRO trial induced higher body dehydration, heart rate, and rectal temperature and a decrease in plasma volume. Orthostatic tolerance was significantly reduced in the PRO trial (23.7 +/- 0.2 min) compared with the CON trial (40.7 +/- 1.0 min). Transition from supine to head-up position caused a significant decrease in blood pressure in the PRO compared with the CON. RR interval was smaller in the PRO trial compared with CON in both the supine and head-up positions. Spontaneous baroreflex sensitivity was decreased in the PRO, either supine or standing, compared to CON (4.6 +/- 0.5 ms x mmHg(-1) and 14.5 +/- 4.2 ms x mmHg(-1) in supine, and 3.3 +/- 0.6 ms x mmHg(-1) and 7.0 +/- 0.6 ms x mmHg(-1) in standing, for PRO and CON, respectively). DISCUSSION: These results suggest that the large decrease in the tolerance to orthostatism after exercise while wearing protective clothing was due to the impossibility of maintaining an adapted blood pressure induced by a conflict between the needs of peripherical vasoconstriction linked to the standing posture, the needs of vasodilatation linked to thermoregulation, and a drop in the sensibility of the spontaneous baroreflex

The Genome of the Toluene-Degrading Pseudomonas veronii Strain 1YdBTEX2 and Its Differential Gene Expression in Contaminated Sand.

The natural restoration of soils polluted by aromatic hydrocarbons such as benzene, toluene, ethylbenzene and m- and p-xylene (BTEX) may be accelerated by inoculation of specific biodegraders (bioaugmentation). Bioaugmentation mainly involves introducing bacteria that deploy their metabolic properties and adaptation potential to survive and propagate in the contaminated environment by degrading the pollutant. In order to better understand the adaptive response of cells during a transition to contaminated material, we analyzed here the genome and short-term (1 h) changes in genome-wide gene expression of the BTEX-degrading bacterium Pseudomonas veronii 1YdBTEX2 in non-sterile soil and liquid medium, both in presence or absence of toluene. We obtained a gapless genome sequence of P. veronii 1YdBTEX2 covering three individual replicons with a total size of 8 Mb, two of which are largely unrelated to current known bacterial replicons. One-hour exposure to toluene, both in soil and liquid, triggered massive transcription (up to 208-fold induction) of multiple gene clusters, such as toluene degradation pathway(s), chemotaxis and toluene efflux pumps. This clearly underlines their key role in the adaptive response to toluene. In comparison to liquid medium, cells in soil drastically changed expression of genes involved in membrane functioning (e.g., lipid composition, lipid metabolism, cell fatty acid synthesis), osmotic stress response (e.g., polyamine or trehalose synthesis, uptake of potassium) and putrescine metabolism, highlighting the immediate response mechanisms of P. veronii 1YdBTEX2 for successful establishment in polluted soil

Reactions of radicals with hydrolyzed Bi(III) ions : a pulse radiolysis study

Radiolytic reduction of BiOClO4 in aqueous solutions leads to the formation of bismuth clusters and larger nanoparticles. The mechanisms of redox reactions of the polycationic Bi(III) species that exist in the solution were investigated with pulse radiolysis. The kinetic and spectral properties of the transients formed by the reaction of these species with the primary radicals from water radiolysis are reported. The single-electron reduction product, Bi9(OH)224+, absorbs at lambdamax = 273 nm, while the OH adduct, Bi9(OH)235+, has a broad absorption spectrum with a maximum at 280 nm and a shoulder at 420 nm. Several rate constants were measured: k (e-aq + Bi9(OH)225+) = 1.2 x 1010 M-1 s-1 and k (OH + Bi9(OH)225+) = 1.5 x 109 M-1 s-1..

Vanadium thiolate complexes for efficient and selective sulfoxidation catalysis: A mechanistic investigation

The structural and electronic properties as well as the catalytic activity toward sulfoxidation of two new vanadium complexes have been investigated. They both possess in their coordination sphere two alkyl thiolate ligands: a dioxido VV complex [VO2LNS2](HNEt3) (1) (LNS2 = 2,2′-(pyridine-2,6-diyl)bis(1,1′- diphenylethanethiol)) and an oxido VIV complex [VOLN2S2] (2) (LN2S2 = 2,2′-(2,2′-bipyridine-6,6′-diyl)bis(1, 1′-diphenylethanethiol)). The X-ray structure of 1 has revealed that the VV metal ion is at the center of a distorted trigonal bipyramid. The optimized structure of 2 obtained by DFT calculations displays a square-pyramidal geometry, consistent with its EPR spectrum characterized by an axial S = 1/2 signal (g⊥ = 1.988, g = 1.966, Ax(V) = 45 × 10 -4 cm-1, Ay(V) = 42 × 10-4 cm-1, Az(V) = 135 × 10-4 cm-1). DFT calculations have shown that the HOMO (highest occupied molecular orbital) of 1 is notably localized on the two thiolate sulfur atoms (56% and 22%, respectively), consistent with the expected covalent character of the VV-S bond. On the other hand, the SOMO (singly occupied molecular orbital) of 2 is exclusively localized at the VIV ion (92%). Complexes 1 and 2 have shown an ability to catalytically oxidize sulfide into sulfoxide. The oxidation reactions have been carried out with thioanisole as substrate and hydrogen peroxide as oxidant. Yields of 80% and 75% have been obtained in 10 and 15 min for 1 and 2, respectively. However, in terms of conversion, 1 is more efficient than 2 (81% and 44%, respectively). More importantly, the reaction is completely selective with no trace of sulfone produced. While 1 displays a poor stability, catalyst 2 shows the same efficiency after five successive additions of oxidant and substrate. The difference in reactivity and stability between both complexes has been rationalized through a mechanism study performed by means of experimental data (51V NMR and EPR spectroscopy) combined with theoretical calculations. It has been shown that the structure of the cis-oxo peroxo V V intermediate species, which is related to its stability, can partly explain these discrepancies

Polyhedral plasmonic nanoclusters through multi-step colloidal chemistry

We describe a new approach to making plasmonic metamolecules with well-controlled resonances at optical wavelengths. Metamolecules are highly symmetric, subwavelength-scale clusters of metal and dielectric. They are of interest for metafluids, isotropic optical materials with applications in imaging and optical communications. For such applications, the morphology must be precisely controlled: the optical response is sensitive to nanometer-scale variations in the thickness of metal coatings and the distances between metal surfaces. To achieve this precision, we use a multi-step colloidal synthesis approach. Starting from highly monodisperse silica seeds, we grow octahedral clusters of polystyrene spheres using seeded-growth emulsion polymerization. We then overgrow the silica and remove the polystyrene to create a dimpled template. Finally, we attach six silica satellites to the template and coat them with gold. Using single-cluster spectroscopy, we show that the plasmonic resonances are reproducible from cluster to cluster. By comparing the spectra to theory, we show that the multi-step synthesis approach can control the distances between metallic surfaces to nanometer-scale precision. More broadly, our approach shows how metamolecules can be produced in bulk by combining different, high-yield colloidal synthesis steps, analogous to how small molecules are produced by multi-step chemical reactions.Advanced Materials by DesignInitiative d'excellence de l'Université de Bordeau

Low dose Rituximab for pre-emptive treatment of Epstein Barr virus reactivation after allogenic hematopoietic stem cell transplantation

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