Search results for "Mechanism"
showing 10 items of 1835 documents
Experimental limits of the observation of thermally activated phase-slip mechanism in superconducting nanowires
2007
The shape of experimentally observed $R(T)$ transition of thin superconducting wires is analyzed. From theoretical point of view, broadening of the transition in quasi-one-dimensional superconducting channels is typically associated with phase-slip mechanism. It is shown that such interpretation can be misleading if to consider geometrical inhomogeneity and finite dimensions of real samples studied in experiments. The analysis is based on experimental fact that for many superconducting materials the critical temperature depends on the characteristic dimension of a sample: film thickness or wire cross section.
New solutions of preparation and activation of surfaces
2017
Organic coatings applied on the surface of cast iron pipes ensure very good chemical and anti-corrosion protection against aggressive effluents. To improve adherence between coating (epoxy) and substrate, a surface preparation is required. Among conventional processes shot blasting has emerged as the most efficient and cheapest solution for ensuring stripping while generating adapted roughness. However, as it may enhance both mechanical anchorage and chemical bonding a better understanding of these phenomena should be developed. Besides new eco-friendly alternatives were investigated.Indeed, new techniques were evaluated, i.e. laser structuring and an ultra-high pressure water jet whose maj…
Chronic myeloid leukemia-derived exosomes promote tumor growth through an autocrine mechanism.
2014
Background Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder in which leukemic cells display a reciprocal t(9:22) chromosomal translocation that results in the formation of the chimeric BCR-ABL oncoprotein, with a constitutive tyrosine kinase activity. Consequently, BCR-ABL causes increased proliferation, inhibition of apoptosis, and altered adhesion of leukemic blasts to the bone marrow (BM) microenvironment. It has been well documented that cancer cells can generate their own signals in order to sustain their growth and survival, and recent studies have revealed the role of cancer-derived exosomes in activating signal transduction pathways involved in cancer cell…
Design and prototyping of a magnetic actuator based permanent magnets for microbead navigation in viscous environment
2017
International audience; For actuating the magnetic microrobots, two types of magnetic actuation technologies have been used during the last past years. These magnetic technologies may be either electromagnetic coils or permanent magnets based systems. This second solution is not the most used by researchers, because of the difficulties to control the magnetic force. In this paper we propose a magnetic actuator prototype based on permanent magnets. In addition to the magnets, the actuator is also composed of a mechanical structure. This structure is used for positioning the permanent magnets, which allows to control the magnetic force generated by the actuator. We demonstrated in simulation …
Motor imagery
2015
International audience; Before participating in a space mission, astronauts undergo parabolic-flight and underwater training to facilitate their subsequent adaptation to weightlessness. Unfortunately, similar training methods can't be used to prepare re adaptation to planetary gravity. Here, we propose a quick, simple and inexpensive approach that could be used to prepare astronauts both for the absence and for the renewed presence of gravity. This approach is based on motor imagery (MI), a process in which actions are produced in working memory without any overt output. Training protocols based on MI have repeatedly been shown to modify brain circuitry and to improve motor performance in h…
The Staminal Lever Mechanism in Salvia L. (Lamiaceae) - a Review
2003
Abstract: The genus Salvia encompasses about 900 species distributed world-wide. It is characterized by the famous staminal lever mechanism of the flower which is one of the best known examples of a nototribic pollination mechanism. We hypothesize that structure and functioning of the staminal levers play a major role as key structures in speciation. To cope with the complex evolutionary processes involved, a number of different methodological approaches are needed. The present paper summarizes the literature referring to structural and functional diversity, breeding systems, systematics and evolution in Salvia.
Design, synthesis, and biological evaluation of novel aminobisphosphonates possessing an in vivo antitumor activity through a gammadelta-T lymphocyte…
2008
A small series of aminobisphosphonates (N-BPs) structurally related to zoledronic acid was synthesized with the aim of improving activity toward activation of human gammadelta T cells and in turn their in vivo antitumor activity. The absence of the 1-OH moiety, together with the position and the different basicity of the nitrogen, appears crucial for antitumor activity. In comparison to zoledronic acid, compound 6a shows a greater ability to activate gammadelta T cells expression (100 times more) and a proapoptotic effect that is better than zoledronic acid. The potent activation of gammadelta T cells, in addition to evidence of the in vivo antitumor activity of 6a, suggests it may be a new…
Hand verification for flexural strength of existing R.C. floors subject to degradation phenomena
2015
Abstract In the present paper, a simplified model for hand verification of the flexural and shear strength of existing corroded T beams cast in place of lightened R.C. orthotropic slabs forming floors is presented and discussed. Diffused and pitting corrosion on steel bars, compressive concrete strength degradation and concrete bond strength degradation are included in the model. The original contribution of the paper is evaluation of the flexural and shear strength considering both the cases of strain compatibility and absence of compatibility and considering the main parameters governing the corrosion process. An arch-resistant model for the calculus of the flexural and shear strength of …
Enhancing salty taste through odour–taste–taste interactions: Influence of odour intensity and salty tastants’ nature
2013
WOS:000315557500017 ; www.elsevier.com/locate/foodqual; International audience; Decreasing the sodium content in food products without changing consumer acceptability has become an important challenge for the food industry, and several strategies are currently under investigation to reach this goal. This study investigated the effectiveness of saltiness enhancement by an odour to maintain the perception of saltiness in reduced salt content solutions. In the first experiment, we tested the hypothesis that odour intensity drives the level of saltiness enhancement. The results showed that odour can increase the salty intensity by 25%, while no clear influence of odour intensity either in taste…
Mechanisms of Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa : Results of the GERPA Multicenter Study
2020
ABSTRACT Resistance mechanisms of Pseudomonas aeruginosa to ceftolozane/tazobactam (C/T) were assessed on a collection of 420 nonredundant strains nonsusceptible to ceftazidime (MIC > 8 μg/ml) and/or imipenem (>4 μg/ml), collected by 36 French hospital laboratories over a one-month period (the GERPA study). Rates of C/T resistance (MIC > 4/4 μg/ml) were equal to 10% in this population (42/420 strains), and 23.2% (26/112) among the isolates resistant to both ceftazidime and imipenem. A first group of 21 strains (50%) was found to harbor various extended-spectrum β-lactamases (1 OXA-14; 2 OXA-19; 1 OXA-35; 1 GES-9; and 3 PER-1), carbapenemases (2 GES-5; 1 IMP-8; and 8 VIM-2), or both (1 VIM-2…