62 research outputs found
Experimental study of super-rotation in a magnetostrophic spherical Couette flow
We report measurements of electric potentials at the surface of a spherical
container of liquid sodium in which a magnetized inner core is differentially
rotating. The azimuthal angular velocities inferred from these potentials
reveal a strong super-rotation of the liquid sodium in the equatorial region,
for small differential rotation. Super-rotation was observed in numerical
simulations by Dormy et al. [1]. We find that the latitudinal variation of the
electric potentials in our experiments differs markedly from the predictions of
a similar numerical model, suggesting that some of the assumptions used in the
model - steadiness, equatorial symmetry, and linear treatment for the evolution
of both the magnetic and velocity fields - are violated in the experiments. In
addition, radial velocity measurements, using ultrasonic Doppler velocimetry,
provide evidence of oscillatory motion near the outer sphere at low latitude:
it is viewed as the signature of an instability of the super-rotating region
Oxaliplatin use in pressurized intraperitoneal aerosol chemotherapy (PIPAC) is safe and effective: A multicenter study.
Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new drug delivery method used in patients with peritoneal cancer (PC) of primary or secondary origin. Intraperitoneal use of oxaliplatin raises concerns about toxicity, especially abdominal pain. The objective of this study was to assess the tolerance of PIPAC with oxaliplatin (PIPAC-Ox) in a large cohort of patients and to identify the risk factors for high grade toxicity, discontinuation of treatment and impaired survival.
This retrospective cohort study included all consecutive patients treated with PIPAC-Ox (92 mg/m <sup>2</sup> ) in five centers specialized in the treatment of PC. The procedure was repeated every 6 weeks. Outcomes of interest were Common Terminology Criteria for Adverse Events (CTCAE), symptoms and survival (Kaplan-Meier). Univariate risk factors were included in a multinominal regression model to control for bias.
Overall, 251 PIPAC-Ox treatments were performed in 101 patients (45 female) having unresectable PC of various origins: 66 colorectal, 15 gastric, 5 ovarian, 3 mesothelioma, 2 pseudomyxoma, 10 other malignancies (biliary, pancreatic, endocrine) respectively. The median PCI was 19 (IQR: 10-28). Postoperative abdominal pain was present in 23 patients. Out of the 9 patients with grade 3 abdominal pain, only 3 needed a change of PIPAC drug. CTCAE 4.0 toxicity grade 4 or higher was encountered in 16(15.9%) patients. The patients had a mean of 2.5 procedures/patient (SD = 1.5). 50 subjects presented with symptom improvement.
Oxaliplatin-based PIPAC appears to be a safe treatment that offers good symptom control and promising survival for patients with advanced peritoneal disease
Zonal shear and super-rotation in a magnetized spherical Couette flow experiment
We present measurements performed in a spherical shell filled with liquid
sodium, where a 74 mm-radius inner sphere is rotated while a 210 mm-radius
outer sphere is at rest. The inner sphere holds a dipolar magnetic field and
acts as a magnetic propeller when rotated. In this experimental set-up called
DTS, direct measurements of the velocity are performed by ultrasonic Doppler
velocimetry. Differences in electric potential and the induced magnetic field
are also measured to characterize the magnetohydrodynamic flow. Rotation
frequencies of the inner sphere are varied between -30 Hz and +30 Hz, the
magnetic Reynolds number based on measured sodium velocities and on the shell
radius reaching to about 33. We have investigated the mean axisymmetric part of
the flow, which consists of differential rotation. Strong super-rotation of the
fluid with respect to the rotating inner sphere is directly measured. It is
found that the organization of the mean flow does not change much throughout
the entire range of parameters covered by our experiment. The direct
measurements of zonal velocity give a nice illustration of Ferraro's law of
isorotation in the vicinity of the inner sphere where magnetic forces dominate
inertial ones. The transition from a Ferraro regime in the interior to a
geostrophic regime, where inertial forces predominate, in the outer regions has
been well documented. It takes place where the local Elsasser number is about
1. A quantitative agreement with non-linear numerical simulations is obtained
when keeping the same Elsasser number. The experiments also reveal a region
that violates Ferraro's law just above the inner sphere.Comment: Phys Rev E, in pres
Insights into metazoan evolution from <i>Alvinella pompejana</i> cDNAs
BackgroundAlvinella pompejana is a representative of Annelids, a key phylum for evo-devo studies that is still poorly studied at the sequence level. A. pompejana inhabits deep-sea hydrothermal vents and is currently known as one of the most thermotolerant Eukaryotes in marine environments, withstanding the largest known chemical and thermal ranges (from 5 to 105°C). This tube-dwelling worm forms dense colonies on the surface of hydrothermal chimneys and can withstand long periods of hypo/anoxia and long phases of exposure to hydrogen sulphides. A. pompejana specifically inhabits chimney walls of hydrothermal vents on the East Pacific Rise. To survive, Alvinella has developed numerous adaptations at the physiological and molecular levels, such as an increase in the thermostability of proteins and protein complexes. It represents an outstanding model organism for studying adaptation to harsh physicochemical conditions and for isolating stable macromolecules resistant to high temperatures.ResultsWe have constructed four full length enriched cDNA libraries to investigate the biology and evolution of this intriguing animal. Analysis of more than 75,000 high quality reads led to the identification of 15,858 transcripts and 9,221 putative protein sequences. Our annotation reveals a good coverage of most animal pathways and networks with a prevalence of transcripts involved in oxidative stress resistance, detoxification, anti-bacterial defence, and heat shock protection. Alvinella proteins seem to show a slow evolutionary rate and a higher similarity with proteins from Vertebrates compared to proteins from Arthropods or Nematodes. Their composition shows enrichment in positively charged amino acids that might contribute to their thermostability. The gene content of Alvinella reveals that an important pool of genes previously considered to be specific to Deuterostomes were in fact already present in the last common ancestor of the Bilaterian animals, but have been secondarily lost in model invertebrates. This pool is enriched in glycoproteins that play a key role in intercellular communication, hormonal regulation and immunity.ConclusionsOur study starts to unravel the gene content and sequence evolution of a deep-sea annelid, revealing key features in eukaryote adaptation to extreme environmental conditions and highlighting the proximity of Annelids and Vertebrates
Influence de l'âge et du sevrage sur les caractéristiques contractiles et métaboliques des fibres musculaires chez le bovin
International audienc
Modélisation dynamique hybride des échangeurs évaporateurs et condenseurs
International audienc
Influence de l'âge et du sevrage sur les caractéristiques contractiles et métaboliques des fibres musculaires chez le bovin
Modélisation dynamique hybride des échangeurs évaporateurs et condenseurs
International audienc
Study of the influence of age and weaning on the contractile and metabolic characteristics of bovine muscle
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