452 research outputs found
Algunos aspectos cinéticos de las reacciones de sólidos con cloro
The present paper describes detailed kinetics investigations on some selected chlorine-solid reactions through thermogravimetric
measurements. The solids studied in this article include chemical pure oxides and sulfides as well as their
natural bearing materials. The chlorinating agents employed are gaseous mixtures of Cl2+N2 (chlorination), Cl2+O2
(oxychlorination), and Cl2+CO (carbochlorination). Results are presented as effects of various parameters on the
reaction rate of these solids with these chlorinating agents. It was observed that the reactivity of these solids towards
different chlorinating agents varied widely. Sulfides could be chlorinated at room temperature, while carbochlorination
of chromium (III) oxide was possible only above 500 °C. The variation of the chlorination rate of these complex
materials with respect to gas velocity, composition and temperature enabled us to focus some light on the plausible
reaction mechanisms and stoichiometries. The obtained results were used for selective removal of iron from chromite
concentrates, extraction of valuable metals from sulfide materials, purification of MgO samples, etc.Este trabajo describe detalladas investigaciones cinéticas en algunas reacciones seleccionadas de cloro-sólido a través
de medidas termogravimétricas. Los sólidos estudiados en este artículo incluyen óxidos químicos puros y sulfuros, así
como sus materiales naturales de soporte. Los agentes de cloración empleados son mezclas de gases de Cl2+N2 (cloración),
Cl2+O2 (oxicloración) y Cl2+CO (carbocloración). Los resultados se presentan como efecto de varios parámetros
en el porcentaje de reacción de estos sólidos con los agentes de cloración. Se ha observado que la reactividad
de estos sólidos a través de diferentes agentes de cloración varía ampliamente. Los sulfuros se pudieron clorar a temperatura
ambiente mientras que la carbocloración del óxido de cromo (III) sólo fue posible por encima de los 500 °C.
La variación del porcentaje de cloración de estos materiales complejos con respecto a la velocidad del gas, composición
y temperatura permitió arrojar alguna luz en los posibles mecanismos de reacción y estequiometrías. Los resultados
obtenidos se han usado para la eliminación selectiva del hierro de concentrados de cromo, extracción de metales
valiosos de materiales sulfhídricos, purificación de muestras de MgO, etc.Peer reviewe
S.11.1 Influence of digital ulcer healing on disability and daily activity limitations in SSc
Objective. We previously showed that DU significantly increased global and hand disability with a significant impact on activities of daily living (ADLs) and work disability. This study aims to evaluate the impact of digital ulcer (DU) healing on disability and daily activity limitations in SSc. Methods. From January 2008 and June 2009, we prospectively evaluated 189 SSc patients for DU history, disability, employment and occupational status during meetings of the French SSc Patient Association (n = 86, 45.5%) or during hospitalization (n = 103, 54.5%)1. Among the 60 patients with at least one active DU at baseline (M0), 40 patients were followed longitudinally over 6 (3) months. These patients were evaluated for DU history, global and hand disability, health-related quality of life (HRQoL), daily activity limitation and employment status. Results. The median (IQR) age was 57.5 (43.5-68) years and the median (IQR) disease duration was 8.3 (3-16.5) years. Twenty-two (55%) patients had diffuse SSc and 34 (85%) were females. At baseline, a mean of 2.9 (2.8) DU per patient was reported. Thirty-three (82.5%) patients had ischaemic DU, 7 (17.5%) patients had >1 DU associated with calcinosis and 13 (32.5%) patients had mechanical DU. Thirteen (32.5%) patients had >4 DU at baseline. Among the 40 patients, 16 (40%) patients showed complete ulcer healing. In these patients with DU, the presence of calcinosis was associated with a lower probability of healing (P = 0.03). Comparison between healed and no-healed DU patients showed an improvement of hand disability provided by an improvement of the Cochin Hand Function score (P = 0.05)) and a trend towards HAQ domain dressing and grooming (P = 0.06) between M0 and M6 (3) visit in healed patients but not in no-healed patients. Concerning HRQoL, there were no difference for Mental and Physical component Scores of SF-36 but significant improvement of Bodily Pain score (P = 0.04) and Physical Role score (P = 0.05) between M0 and M6 (3) visit in patients with healed DU. The absence of healing was associated with significantly decreased work productivity (P = 0.05), whereas the performance in ADL was not significantly decreased (P = 0.15). Patients who were on sick-leave and who received some help for household tasks at the time of active DU were more likely to heal. Conclusion. For the first time, we provide prospective data with evidence that DU healing is associated with an improvement in hand function. Sick leave was associated with better healing of D
A simulated annealing based genetic local search algorithm for multi-objective multicast routing problems
This paper presents a new hybrid evolutionary algorithm to solve multi-objective multicast routing problems in telecommunication networks. The algorithm combines simulated annealing based strategies and a genetic local search, aiming at a more flexible and effective exploration and exploitation in the search space of the complex problem to find more non-dominated solutions in the Pareto Front. Due to the complex structure of the multicast tree, crossover and mutation operators have been specifically devised concerning the features and constraints in the problem. A new adaptive mutation probability based on simulated annealing is proposed in the hybrid algorithm to adaptively adjust the mutation rate according to the fitness of the new solution against the average quality of the current population during the evolution procedure. Two simulated annealing based search direction tuning strategies are applied to improve the efficiency and effectiveness of the hybrid evolutionary algorithm. Simulations have been carried out on some benchmark multi-objective multicast routing instances and a large amount of random networks with five real world objectives including cost, delay, link utilisations, average delay and delay variation in telecommunication networks. Experimental results demonstrate that both the simulated annealing based strategies and the genetic local search within the proposed multi-objective algorithm, compared with other multi-objective evolutionary algorithms, can efficiently identify high quality non-dominated solution set for multi-objective multicast routing problems and outperform other conventional multi-objective evolutionary algorithms in the literature
The heparan sulfate sulfotransferase 3-OST3A (HS3ST3A) is a novel tumor regulator and a prognostic marker in breast cancer
International audienceHeparan sulfate (HS) proteoglycan chains are key components of the breast tumor microenvironment that critically influence the behavior of cancer cells. It is established that abnormal synthesis and processing of HS play a prominent role in tumorigenesis, albeit mechanisms remain mostly obscure. HS function is mainly controlled by sulfotransferases, and here we report a novel cellular and pathophysiological significance for the 3-O-sulfotransferase 3-OST3A (HS3ST3A), catalyzing the final maturation step of HS, in breast cancer. We show that 3-OST3A is epigenetically repressed in all breast cancer cell lines of a panel representative of distinct molecular subgroups, except in human epidermal growth factor receptor 2-positive (HER2+) sloan-kettering breast cancer (SKBR3) cells. Epigenetic mechanisms involved both DNA methylation and histone modifications, producing different repressive chromatin environments depending on the cell molecular signature. Gain and loss of function experiments by cDNA and siRNA transfection revealed profound effects of 3-OST3A expression on cell behavior including apoptosis, proliferation, response to trastuzumab in vitro and tumor growth in xenografted mice. 3-OST3A exerted dual activities acting as tumor-suppressor in lumA-michigan cancer foundation (MCF)-7 and triple negative-MD Anderson (MDA) metastatic breast (MB)-231 cells, or as an oncogenic factor in HER2+-SKBR3 cells. Mechanistically, fluorescence-resonance energy transfer-fluorescence-lifetime imaging microscopy experiments indicated that the effects of 3-OST3A in MCF-7 cells were mediated by altered interactions between HS and fibroblast growth factor-7 (FGF-7). Further, this interplay between HS and FGF-7 modulated downstream ERK, AKT and p38 cascades, suggesting that altering 3-O-sulfation affects FGFR2IIIb-mediated signaling. Corroborating our cellular data, a clinical study conducted in a cohort of breast cancer patients uncovered that, in HER2+ patients, high level expression of 3-OST3A in tumors was associated with reduced relapse-free survival. Our findings define 3-OST3A as a novel regulator of breast cancer pathogenicity, displaying tumor-suppressive or oncogenic activities in a cell-and tumor-dependent context, and demonstrate the clinical value of the HS-O-sulfotransferase 3-OST3A as a prognostic marker in HER2+ patients
Aérosols de médicaments
L\u27aérosolthérapie a bénéficié ces dernières années de progrès technologiques considérables au niveau des générateurs d\u27aérosols. Les aérosols doseurs liquides HFA avec ou sans chambre d\u27inhalation, les aérosols doseurs de poudre ont vu leurs indications respectives précisées. Les systèmes de nébulisation ont également progressé avec notamment l\u27apparition des nébuliseurs à membranes. La nébulisation permet de traiter les formes les plus sévères des maladies repiratoires, asthme, BPCO, mucoviscidose, par les bronchodilatateurs, les corticoïdes, les antibiotiques et la rhDNase I. L\u27utilisation de la nébulisation trouve depuis peu des applications pour le traitement de maladies systémiques telles que le diabète ou l\u27hypertension artérielle pulmonaire. Des perspectives apparaissent également pour la chimiothérapie antitumorale et la vaccination par aérosols. Les conditions optimales de prescription, d\u27administration et de suivi de l\u27aérosolthérapie ont été définies
Unbiased yeast screens identify cellular pathways affected in Niemann-Pick disease type C
Niemann–Pick disease type C (NPC) is a rare lysosomal storage
disease caused by mutations in either the NPC1 or NPC2 genes.
Mutations in the NPC1 gene lead to the majority of clinical cases
(95%); however, the function of NPC1 remains unknown. To gain
further insights into the biology of NPC1, we took advantage of
the homology between the human NPC1 protein and its yeast
orthologue, Niemann–Pick C–related protein 1 (Ncr1). We recreated the NCR1 mutant in yeast and performed screens to identify
compensatory or redundant pathways that may be involved in
NPC pathology, as well as proteins that were mislocalized in
NCR1-deficient yeast. We also identified binding partners of the
yeast Ncr1 orthologue. These screens identified several processes
and pathways that may contribute to NPC pathogenesis. These
included alterations in mitochondrial function, cytoskeleton
organization, metal ion homeostasis, lipid trafficking, calcium
signalling, and nutrient sensing. The mitochondrial and cytoskeletal abnormalities were validated in patient cells carrying
mutations in NPC1, confirming their dysfunction in NPC disease
Identifiability of flow distributions from link measurements with applications to computer networks
We study the problem of identifiability of distributions of flows on a graph from aggregate measurements collected on its edges. This is a canonical example of a statistical inverse problem motivated by recent developments in computer networks. In this paper (i) we introduce a number of models for multi-modal data that capture their spatio-temporal correlation, (ii) provide sufficient conditions for the identifiability of nth order cumulants and also for a special class of heavy tailed distributions. Further, we investigate conditions on network routing for the flows that prove sufficient for identifiability of their distributions (up to mean). Finally, we extend our results to directed acyclic graphs and discuss some open problems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58107/2/ip7_5_004.pd
Tailored Protocol Development Using ESTEREL
The rapid evolution of networking and the multiplication of new applications re-emphasizes the importance of the efficient communication supports. Implementations must be able to take maximal advantage of the details of application-specific semantics and of specific networking environments. In other words, the application needs to have more control over data transmission. Such control can be obtained by tailoring the communication facilities (or protocols) to the application characteritics, and by integrating the communication control to the application. Because such a task is too complex to be realized manually, we propose to automate the protocol development process using a formal approach. This report presents our approach to the automated design and implementation of application- specific communication protocols based on information provided by the application. Starting from the formal description of an application, our approach is based on a tool called "Protocol Compiler" that will automatically produce the implementation of a communication protocol tailored to the application. The formalism we use is ESTEREL, a synchronous reactive language dedicated to the description of real-time systems. Protocol description and verification using ESTEREL are described, as well as protocol optimization and implementation principles
Risk factors for death and the 3-year survival of patients with systemic sclerosis: the French ItinérAIR-Sclérodermie study
Objectives. This longitudinal study investigated survival, risk factors and causes of death in the multicentre ItinérAIR-Sclérodermie cohort of patients with SSc without severe pulmonary fibrosis or severe left heart disease at baseline
Evidence of the contribution of the X chromosome to systemic sclerosis susceptibility: Association with the functional IRAK1 196Phe/532Ser haplotype
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