Corrosion intercristalline du nickel

The aim of our study is to investigate the influence of the grain size and of the surface state on the passivation-depassivation phenomenon, for nickel in normal sulphuric acid. Up to a value of 750 mV vs S.S.E., an instantaneous depassivation leads to an I(t) response which tends towards a stable value of the current, whatever the electrode structure and surface state might be. Corrosion is essentially of an intergranular type. For higher values of potential, electrode response during depassivation is quite different. Current intensity never tends towards a stable value whatever the grain size and the kind of polishing of the sample, this leads to different corrosion facets.     

Brugia pahangi: effects of protective resistance on lymphatic lesions and granulomatous inflammation in infected jirds (Meriones unguiculatus)

Effects of protective resistance on lymphatic lesions and granulomatous inflammation in infected jirds (Meriones unguiculatus). Experimental Parasitology 77, 395-404. The hypothesis that protective immune responses play a role in the induction of filarial-associated lymphatic lesions was tested in jirds immunized twice with 75 Brugia pahangi radiation-attenuated third-stage larvae. Lymphatic lesions and granulomatous reactivity were compared in immunized, infected, and naive jirds at both acute and chronic periods following challenge with 100 third-stage larvae. Challenge worm burdens were reduced in immunized jirds at both infection periods. The ratio of lymph thrombi to lymphatic worms, an indicator of lymphatic lesion severity, was significantly greater in immunized jirds than in nonimmunized-challenged jirds during acute but not chronic infections. Parasite-specific-granulomatous hypersensitivity was assessed by measurements of granuloma areas around B. pahangi-soluble adult worm antigen-coated sepharose beads embolized in the lungs prior to necropsy. Marked granulomatous inflammatory responses seen during the acute period in both immunized-challenged and nonimmunized-challenged jirds were significantly reduced in similar jirds during chronic periods. Jirds with existing B. pahangi infections were not resistant to homologous challenge infection and had fewer lymphatic lesions and reduced granulomatous inflammatory responses to soluble adult worm antigen compared to previously naive jirds at acute periods postchallenge. These data suggest that protective immune responses increase the severity of filariae-induced lymphatic inflammation. The subsequent modulation of these lesions is probably associated with parasites that survived the protective immune response.     

Cytofluorometric analysis of chondrotoxicity of fluoroquinolone antimicrobial agents

Betulinic acid [1] and platanic acid [2], isolated from the leaves of Syzigium claviforum, were found to be inhibitors of HIV replication in H9 lymphocyte cells. Evaluation of anti-HIV activity with eight derivatives of 1 revealed that dihydrobetulinic acid [3] was also a potent inhibitor of HIV replication. The C-3 hydroxy group and C-17 carboxylic acid group, as well as the C-19 substituents, contribute to enhanced anti-HIV activity. The inhibitory activity of these compounds against protein kinase C (PKC) was also examined, since a correlation between anti-HIV and anti-PKC activities has been suggested. However, there was no apparent correlation between anti-HIV activity and the inhibition of PKC among these compounds.     

Albumin-impregnated polyester vascular prosthesis for abdominal aortic surgery: an improvement?

AIM: To compare the peroperative blood loss and the postoperative systemic inflammatory reaction in patients receiving either a Vasculour II Albumin pre-impregnated prosthesis (VA group, n = 32) or a preclotted Vasculour II prosthesis (V group, n = 33) for elective surgery of the abdominal aorta. SETTING: University Hospital. DESIGN: Prospective, randomised study. METHODS: Peroperative blood loss was measured over two different periods: Phase I from the beginning of the operation to the completion of the proximal anastomosis, when blood loss cannot be related to the model of prosthesis implanted and phase II after the completion of the proximal anastomosis to the end of the operation. Postoperative blood loss was evaluated by the determination of the retroperitoneal drainage volume over a period of 2 days immediately following the operation. The presence of periprosthetic fluid was measured with echography at days 4, 9, 30 and 60. The postoperative systemic inflammatory reaction was evaluated by measuring the sedimentation rate and the C reactive protein levels daily from day 1 to day 9, and at days 14, 21, 28, 45, and 60, and by measuring the body temperature daily from day 1 to day 9. RESULTS: No significant differences of peroperative blood loss were observed. The same proportion of patients (35%) in both groups received homologous transfusion. The mean number of units of homologous blood transfused per patient was respectively 0.77 and 0.91 for the VA and the V group. The retroperitoneal drainage volume and the percentage of patients with periprosthetic fluid did not differ significantly. No significant differences in systemic postoperative inflammatory reaction were observed. CONCLUSION: There were no benefits in using albumin-impregnated prosthesis as opposed to preclotted prosthesis in terms of peroperative and postoperative blood loss, or by looking at the incidence of homologous blood transfusion. However, the glutaraldehyde cross-linked albumin did not induce any systemic inflammatory reaction.     

Feedback control and optimization for the production of commercial fuels by blending

This paper presents a control algorithm for blending systems. Such systems are used in refining to produce mixtures having specified properties from several components. The underlying control problem is multi-variable, with constraints on the inputs and outputs, and involves large uncertainties. To address this complexity, a constrained optimization problem is formulated, while the uncertainties are treated in closed-loop by an estimator of the components properties. Besides a theoretical study of the main algorithm and a study of convergence, the paper presents numerous technical details that are needed to solve blending problems as they appear in refining operations. Among them are a general lack of measurements, variable delays, measurement synchronization, infeasibilities management, hydraulic constraints, and pre-blends. Industrial case-studies are provided and stress the relevance of the approach.     

Design and Characterization of an Inhalation System of Iron and Manganese Oxide Nanoparticles for Rodent Exposure

Because of the rise of anthropogenic sources of NP human exposure to NP has dramatically increased in the recent years, in the general population as well as in workers (e.g., welders). This raises the question of the potential adverse effects of NP on human health, particularly at the respiratory level, since it represents the main route of exposure for air pollutants. Since inhalation exposure is the most relevant but yet under evaluated route of exposure for the evaluation of NP toxicity our study was aimed to design, build, and characterize a safe inhalation system dedicated to evaluate the respiratory effects of NP in mice. We chose to focus on the generation of iron (Fe) and manganese (Mn) oxide NP distributions centered on 20–25 nm diameters at concentrations of 10⁷–10⁸ NP/cm³ as it is representative of the occupational exposure of welders. Fe and Mn NP aerosols were generated with the spark discharge generator technique with air as a carrier gas conditio sine qua non for the mice. Indeed, the spark generator has been widely studied and used but in noble gases (N2, Ar,?.?.?.) suggests the absence of oxidation. Aerosol particles are characterized in terms of size distribution, concentration, morphology, and chemical composition. Exposure of mice for 1 to 4 days (3 h a day) to these occupationally relevant aerosol concentrations induces inflammatory effects (increased lung total protein content). Moreover, clusters of particles were observed throughout the lungs.

Copyright © 2015 American Association for Aerosol Research     

Thermal properties and surface reactivity in simulated body fluid of new strontium ion-containing phosphate glasses

In this paper, we investigate the effect of SrO substitution for CaO in 50P₂O₅–10Na₂–(40?x)CaO–xSrO glass system (x from 0 to 40) on the thermal and structural properties and also on the glass reactivity in simulated body fluid (SBF) in order to find new glass candidates for biomedical glass fibers. The addition of SrO at the expense of CaO seems to restrain the leaching of phosphate ions in the solution limiting the reduction of the solution pH. We observed the formation of an apatite layer at the surface of the glasses when in contact with SBF. SrO and MgO were found in the apatite layer of the strontium ion-containing glasses, the concentration of which increases with an increase of SrO content. We think that it is the presence of MgO and SrO in the layer which limits the leaching of phosphate in the solution and thus the glass dissolution in SBF.     

Chronos: a NoSQL system on flash memory for industrial process data

Within Électricité de France (EDF) hydroelectric power stations, IGCBoxes are industrial mini PCs dedicated to industrial process data archiving. These equipments expose distinctive features, mainly on their storage system based exclusively on flash memory due to environmental constraints. This type of memory had notable consequences on data acquisition performance, with a substantial drop compared with hard disk drives. In this setting, we have designed Chronos, an open-source NoSQL system for sensor data management on flash memories. Chronos includes an efficient quasi-sequential write pattern along with an index management technique adapted for process data management. As a result, Chronos supports a higher velocity for inserted data, with acquisition rates improved by a factor of 20–54 over different solutions, therefore solving a practical bottleneck for EDF.     

Mixed-mode separation in dynamic fracture mechanics: New path independent integrals

This paper presents a theoretical and numerical analysis of mixed-mode separation in fracture dynamics, based on new path independent integrals. The M-integral method proposed by Chen and Shield is generalized for dynamic fracture applications. Strain energy density is expressed as a function of the actual displacement field and of an auxiliary kinematically admissible field. On the other hand, the concept of the G-integral developed by Destuynder using the Rice J-integral is extended to dynamic problems. Introducing the same concept in the M-integral formulation leads to the new path-independent integral M in elastodynamics. Numerical tests give us accurate results of separated mode.