2,395 research outputs found
Rheological study of two-phase secondary fluids for refrigeration and air conditioning.
National audienceThe two phase fluids have promising application in refrigeration thanks to their large cooling capacity and their storage ability. However, the lack of information on their properties makes the selection of a proper fluid uneasy. An experimental set-up inspired from the scrapped surface heat exchanger technology is presented in this paper. It was developed both to generate and to characterise slurries in a rheological point of view. The large range of temperature envisaged here allows enlarging the field of application of the technology to cooler temperatures (freezer applications) and to positive ones (air conditioning systems). The principle of the viscosity measurements is described on solutions of ethyl alcohol; a hydrate is also presented as an example of compound showing a dissociation temperature in the range concerned by air conditioning applications
L'émergence d'une "élite du Welfare" ? Sociologie des sommets de l'Etat en interaction
Ce rapport de recherche collective propose une analyse du role joué par un certain nombre de hauts fonctionnaires dans deux secteur de la protection sociale: l'assurance maladie et les politiques de la famille durant la période qui va de 1981 à 1997
Perturbative Unification of Soft Supersymmetry--Breaking Terms
Perturbative unification of soft supersymmetry--breaking (SSB) parameters is
proposed in Gauge-Yukawa unified models. The method, which can be applied in
any finite order in perturbation theory, consists in searching for
renormalization group invariant relations among the SSB parameters, which are
consistent with perturbative renormalizability. For the minimal Gauge-Yukawa
unified model based on we find that the low energy SSB sector contains
a single arbitrary parameter, the unified gaugino mass. Within a certain
approximation we find that the model predicts a superpartner spectrum which is
consistent with the experimental data.Comment: 14 page
Metformin-mediated increase in DICER1 regulates microRNA expression and cellular senescence
Metformin, an oral hypoglycemic agent, has been used for
decades to treat type 2 diabetes mellitus. Recent studies indicate
that mice treated with metformin live longer and have fewer
manifestations of age-related chronic disease. However, the
molecular mechanisms underlying this phenotype are unknown.
Here, we show that metformin treatment increases the levels of
the microRNA-processing protein DICER1 in mice and in humans
with diabetes mellitus. Our results indicate that metformin
upregulates DICER1 through a post-transcriptional mechanism
involving the RNA-binding protein AUF1. Treatment with metformin
altered the subcellular localization of AUF1, disrupting its
interaction with DICER1 mRNA and rendering DICER1 mRNA
stable, allowing DICER1 to accumulate. Consistent with the role
of DICER1 in the biogenesis of microRNAs, we found differential
patterns of microRNA expression in mice treated with metformin
or caloric restriction, two proven life-extending interventions.
Interestingly, several microRNAs previously associated with
senescence and aging, including miR-20a, miR-34a, miR-130a,
miR-106b, miR-125, and let-7c, were found elevated. In agreement
with these findings, treatment with metformin decreased
cellular senescence in several senescence models in a DICER1-
dependent manner. Metformin lowered p16 and p21 protein
levels and the abundance of inflammatory cytokines and oncogenes
that are hallmarks of the senescence-associated secretory
phenotype (SASP). These data lead us to hypothesize that
changes in DICER1 levels may be important for organismal aging
and to propose that interventions that upregulate DICER1
expression (e.g., metformin) may offer new pharmacotherapeutic
approaches for age-related disease
Barnes maze test for spatial memory: A new, sensitive scoring system for mouse search strategies
The Barnes maze is a task used to assess spatial learning and memory in rodents. It requires animals to learn the position of a hole that can be used as an escape from a bright and open arena. The often-used parameters of latency and path length to measure learning and memory do not reflect the different navigation strategies chosen by the animals. Here, we propose an 11-point scoring scheme to classify the search strategies developed by the animals during the initial training as well as after the change of the escape target to a new position. Strategy scores add an important dimension to time and path length to assess the behavior in this popular maze
Automated fragment identification for electron ionisation mass spectrometry: application to atmospheric measurements of halocarbons
Non-target screening consists in searching a sample for all present
substances, suspected or unknown, with very little prior knowledge about the
sample. This approach has been introduced more than a decade ago in the field
of water analysis, together with dedicated compound identification tools, but
is still very scarce for indoor and atmospheric trace gas measurements, despite
the clear need for a better understanding of the atmospheric trace gas
composition.For a systematic detection of emerging trace gases in the
atmosphere, a new and powerful analytical method is gas chromatography (GC) of
preconcentrated samples, followed by electron ionisation, high resolution mass
spectrometry (EI-HRMS). In this work, we present data analysis tools to enable
automated fragment formula annotation for unknown compounds measured by
GC-EI-HRMS. Based on co-eluting mass/charge fragments, we developed an
innovative data analysis method to reliably reconstruct the chemical formulae
of the fragments, using efficient combinatorics and graph theory. The method
does not require the presence of the molecular ion, which is absent in ~40% of
EI spectra. Our method has been trained and validated on \textgreater50
halocarbons and hydrocarbons, with 3 to 20 atoms and molar masses of 30 to 330
g mol-1, measured with a mass resolution of approx.~3500. For 90% of the
compounds, more than 90% of the annotated fragment formulae are correct. Cases
of wrong identification can be attributed to the scarcity of detected fragments
per compound or the lack of isotopic constraint (no minor isotopocule
detected).Our method enables to reconstruct most probable chemical formulae
independently from spectral databases. Therefore, it demonstrates the
suitability of EI-HRMS data for non-target analysis and paves the way for the
identification of substances for which no EI mass spectrum is registered in
databases. We illustrate the performances of our method for atmospheric trace
gases and suggest that it may be well suited for many other types of samples.
The L-GPL licenced Python code is released under the name ALPINAC for
ALgorithmic Process for Identification of Non-targeted Atmospheric Compounds.Comment: Journal of Cheminformatics, Chemistry Central Ltd. and BioMed
Central, 202
A subset of patients with systemic lupus erythematosus fails to degrade DNA from multiple clinically relevant sources
Patients with systemic lupus erythematosus (SLE) have a decreased ability to clear cell remnants and multiple deficiencies in the ability to degrade cellular chromatin have been linked to the disease. Since the discovery of neutrophil extracellular traps (NETs), a renewed interest has been sparked in this field of research with multiple studies reporting a decreased ability of patients with SLE to degrade NETs. In this study we extend these findings by investigating the ability of patients with SLE to degrade chromatin from multiple clinically relevant sources
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