Atmospheric Pressure Nanosecond Pulsed Discharge Plasmas

International audienc

Time-Resolved CRDS Measurements of the N-2(A(3)Sigma(+)(u)) Density Produced by Nanosecond Discharges in Atmospheric Pressure Nitrogen and Air

International audienceCavity ring-down spectroscopy (CRDS) is used to measure the number density of N-2(A(3)Sigma(+)(u)) metastables produced by nanosecond repetitively pulsed discharges in nitrogen and air preheated at 1000 K and atmospheric pressure. The densities of N2(A) are inferred from the absorbance of the Q(1)(22) and Q(3)(16) lines of the (2 <- 0) vibrational band of the first positive system (B-3 Pi g - A(3)Sigma(+)(u)) of N-2 at 769.945 nm. The procedure for determining the temporal evolution of the density of metastable from the measured ring down signals is presented. The maximum number densities are in the range of 10(14)-10(15) molecules cm(-3) for air and nitrogen discharges, respectively. In nitrogen, the decay of the N2(A) density is shown to be a second-order process with a rate coefficient of 1.1 x 10(-9) cm(3) s(-1) at 1600 K with a factor of 2 uncertainty. In air, the decay is estimated to be I order of magnitude faster than that in nitrogen owing to quenching by atomic and molecular oxygen. Furthermore, the rotational temperature is determined by comparison of CRDS measurements and simulations of several rotational lines of the (2 <- 0) band of the first positive system of N-2 between 769.8 and 770.7 nm. The rotational and vibrational temperatures are also determined by comparison of optical emission measurements and simulations of the second positive system of N-2 between 365 and 385 nm. In these CRDS measurements, we achieved a temporal resolution down to 50 ns

Study of NRP discharges in atmospheric presure air used for flame stabilization by TALIF and CRDS

International audienc

New distributional records for ants and the evaluation of ant species richness and endemism patterns in Mexico

Ants (Formicidae) in Mexico have been usually undersampled despite their ecological significance and their utility as service providers and bioindicators. This study estimates the species richness and the narrow endemic species number of ants across Mexico. It also documents the presence of one species newly recorded in Mexico and 19 new state-based records of 14 species from central and north Mexico. No surveys have been performed in most of the localities where we report those records, suggesting the need of a higher sampling effort in the country.We present an ant species richness estimation in a grid of 0.5 degrees in Mexico and a narrow endemic ant species estimation. Stenamma schmitii is reported for the first time from Mexico. Additionally, the new state-based records of Azteca velox, Dorymyrmex insanus, Camponotus coruscus, Camponotus striatus, Formica propatula, Lasius latipes, Neivamyrmex melanocephalus, Neivamyrmex rugulosus, Syscia augustae, Atta texana, Cephalotes scutulatus, Crematogaster crinosa and Temnothorax andrei are reported

Protein kinase C-dependent {alpha}-secretory processing of the amyloid precursor protein is mediated by phosphorylation of myosin II-B

A substantial body of evidence indicates that protein kinase C (PKC) is involved in the alpha-secretory processing of the amyloid precursor protein (APP), an event that reduces the formation of the pathogenic amyloid-beta peptide. Recently, we have shown that trafficking and processing of APP are both impaired by knockdown of myosin II-B, one of the major neuronal motor proteins. Here, we provide evidence that the alpha-secretory processing of APP is mediated by PKC-dependent phosphorylation of myosin II-B. This signaling pathway provides an important link between APP and the neuronal cytoskeleton and might be crucial for the understanding of the biological and pathological roles of APP

In Vitro Antimicrobial Activity of Embothrium coccineum Used as Traditional Medicine in Patagonia against Multiresistant Bacteria

Embothrium coccineum J.R. Forst. &amp; G. Forst is an evergreen tree that has been used as a folk remedy for the treatment of neuralgia, tooth pains, wound healing, and glandular conditions, as well as an antiseptic agent against bacterial infection. The antibacterial activities of sequential extracts (hexane, dichloromethane, ethyl acetate, and ethanol) from the leaves of E. coccineum were evaluated by means of the micro-dilution assay against six (Escherichia coli; Klebsiella pneumoniae; Proteus mirabilis; Pseudomonas aeruginosa; Staphylococcus aureus and Streptococcus pyogenes) multiresistant bacteria strains. Ethyl acetate extract showed the best spectra of antibacterial activity against all tested bacteria, and was analyzed by gas chromatography–mass spectrometry (GC-MS) for its composition. The results of the present work provide useful baseline information for the potential development and use of nanoparticles and/or nanofibers doped with extracts of E. coccineum in the fight against multiresistant bacteria, which would allow the validation of the traditional use of E. coccineum by native peoples of Patagonia as an antimicrobial agent in the biomedical Field