Application of classical thermodynamics to the conductivity in non-polar media.

Electrical conductivity in non-polar media is a subject which recently regained interest. If most of experiments and theoretical developments were done more than 50 years ago, new experiments and theories have been recently published. As the electrical conductivity describes, at low field, the equilibrium state of a system, it is natural to apply theories based on equilibrium thermodynamics. In this article, well-established classical thermodynamics and solvations models are applied to recently published data. This enables to get a new insight in intriguing phenomena, such as the linear dependence of the conductivity on the concentration of ionic surfactant and the evaluation of conductivity for the mixture of two miscible fluids, such as alcohol and alcane, which have very different conductivities.

Nonideal effects in electroacoustics of solutions of charged particles: combined experimental and theoretical analysis from simple electrolytes to small nanoparticles.

The electric signal induced by an ultrasonic wave in aqueous solutions of charged species is measured and analyzed. A device is developed which measures the raw induced electric signal for small sample volumes (few milliliters) and without any preceding calibration. The potential difference generated between two identical electrodes, called the ionic vibration potential (IVP), is thus easily deduced. In parallel, a theory for the IVP is built based on a robust analytical theory already used successfully to account for other transport coefficients in electrolyte solutions. From the analysis of the IVP measured for several aqueous electrolyte solutions, which are well-defined model systems for this technique, we explain and validate the different contributions to the signal. In particular, the non-ideal effects at high concentrations are thoroughly understood. A first step towards colloidal systems is presented by the analysis of the signal in solutions of a polyoxometallate salt, opening the possibility of determinations of reliable electrophoretic mobilities in dispersions of nanoobjects.

Onsager's reciprocal relations for electroacoustic and sedimentation: Application to (concentrated) colloidal suspensions.

In this article, the relations for electroacoustic phenomena, such as sedimentation potential, sedimentation intensity, colloid vibration potential, colloid vibration intensity/current, or electric sonic amplitude, are given, on the basis of irreversible thermodynamics. This formalism allows in particular to discuss the different expressions for concentrated suspensions found by various authors, which are of great practical interest. It was found that some existing expressions have to be corrected. Relations between the electrophoretic mobilities assessed by the different experiments are derived.

Onsager's reciprocal relations in electrolyte solutions. I. Sedimentation and electroacoustics.

In the framework of irreversible thermodynamics, we show that the sedimentation current in electrolyte solutions is mathematically equivalent to the low frequency limit of the ionic vibration current, appearing in the presence of an acoustic wave. This non-trivial result is obtained thanks to a careful choice of the reference frame used to express the mass fluxes in the context of electroacoustics. Coupled transport phenomena in electrolyte solutions can also be investigated in a mechanical framework, with a set of Newtonian equations for the dynamics of charged solutes. Both in the context of sedimentation and of electroacoustics, we show that the results obtained in the mechanical framework, in the ideal case (i.e., without interactions between ions), do satisfy the Onsager's reciprocal relations. We also derive the general relation between corrective forces accounting for ionic interactions which must be fulfilled so that the Onsager's reciprocal relations are verified. Finally, we show that no additional diffusion term needs to be taken into account in the flux of solutes (far from the walls), even if local concentration gradients exist, contrarily to what was done previously in the literature.

Onsager's reciprocal relations in electrolyte solutions. II. Effect of ionic interactions on electroacoustics.

In electrolyte solutions, an electric potential difference, called the Ionic Vibration Potential (IVP), related to the ionic vibration intensity, is generated by the application of an acoustic wave. Several theories based on a mechanical framework have been proposed over the years to predict the IVP for high ionic strengths, in the case where interactions between ions have to be accounted for. In this paper, it is demonstrated that most of these theories are not consistent with Onsager's reciprocal relations. A new expression for the IVP will be presented that does fulfill the Onsager's reciprocal relations. We obtained this expression by deriving general expressions of the corrective forces describing non-ideal effects in electrolyte solutions.

[The ethical aspects of physiological experiment].

A modern classification of invasive procedures developed according to International Bioethical Principles has been presented. The experimental data convincingly demonstrate that using of noninvasive approaches and techniques give a good opportunity to reduce a number of animals recruited in experiment as well as to keep the normal (not distressful) physiological functions of animals. The data presented stress that development of noninvasive techniques is closely related both to scientific and social aspects of our life, allowing the scientists to provide high validity of experimental data obtained as well as to keep themselves as a human beings.

Coastal current convergence structures in the Bay of Biscay from optimized high-frequency radar and satellite data.

The southeastern Bay of Biscay has been described as a "dead end" for floating marine litter, often accumulating along small-scale linear streaks. Coastal Current Convergence Structures (CCS), often associated with vertical motions at river plume edges, estuarine fronts, or other physical processes, can be at the origin of the accumulation. Understanding the formation of CCS and their role in the transport of marine litter is essential to better quantify and to help mitigate marine litter pollution. The Lagrangian framework, used to estimate the absolute dispersion, and the finite-size Lyapunov exponents (FSLE), have proved very effective for identifying CCS in the current velocity field. However, the quality of CCS identification depends strongly on the Eulerian fields. Two surface current velocity data sets were used in the analysis: the remotely sensed velocities from the EuskOOS High-Frequency Radar (HFR) network and velocities from three-dimensional model outputs. They were complemented by drifting buoy velocity measurements. An optimization method, involving the fusion of drifting buoys and HFR velocities is proposed to better reconstruct the fine-scale structure of the current velocity field. Merging these two sources of velocity data reduced the mean Lagrangian error and the Root Mean Square Error (RMSE) by 50 % and 30 % respectively, significantly improving velocity reconstruction. FSLE ridgelines obtained from the Lagrangian analysis of optimized velocities were compared with remotely sensed concentrations of Chlorophyll-a. It was shown that ridgelines control the spatial distribution of phytoplankton. They fundamentally represent the CCS which can potentially affect marine litter aggregation. Analysis of the absolute dispersion revealed large stirring in the alongshore direction which was also confirmed by spatial distribution of FSLE ridgelines. The alignment between FSLE ridgelines and patterns of high Chlorophyll-a concentration was observed, often determining the limits of river plume expansion in the study area.

The evaluation of adenoid hypertrophy and obstruction grading based on rhinomanometry after nasal decongestant test in children.

OBJECTIVES: Adenoid hypertrophy (AH) is a very common problem in children. Nasal Fiberoptic Endoscopy (NFE) represents the gold standard method to diagnose AH. Rhinomanometry represents a valid diagnostic support. The aim of our study was to analyze the grade of nasal obstruction caused by AH, in a group of children, with rhinomanometry standard and after ND test versus NFE. PATIENTS AND METHODS: Two hundred and eighty-four of 300 collaborative children, diagnosed as chronic oral breathers, were enrolled. All children underwent a complete physical examination, anterior active rhinomanometry and a second rhinomanometry after the administration of the nasal decongestant (ND) xylometazoline. All children were evaluated using Nasal Fiberoptic Endoscopy (NFE). RESULTS: At rhinomanometry nasal obstrucion was found of grade 1 in 102 (35.9%) children, of grade 2 in 41 (14.4%), of grade 3 in 52 (18.3%), of grade 4 in 37 (13%) and of grade 5 in 52 (18.3%). Those patients were tested also with rhinomanometry after ND: grade 1 in 108 (38%) children, grade 2 in 52 (18.3%), grade 3 in 56 (19.7%), grade 4 in 23 (8.1%) and grade 5 in 45 (15.8%). At NFE: 83 (29.2%) patients presented a grade 0, 73 (28.7%) a grade 1, 51 (17.9%), 34 (11.9%) a grade 3 and 43 (15.1%) a grade 4. Comparing the grade of nasal obstruction in NFE and in RM after ND we found a great correlation for grade 1 and grade 5 (respectively 84.3% and 79,1%, p < 0.001) and low correlation for the others grades of obstruction. When compared to NFE, rhinomanometry test after ND had 81.1% sensitivity and 84.3% specificity. Operating Characteristic (ROC) curves were derived using data related to rhinomanometry vs NFE, and to Rhinomanometry after ND vs NFE. CONCLUSIONS: Rhinomanometry after ND, compared to rmhinomanometry, is more specific and useful to evaluate nasal obstruction due to AH in children. RM after ND is a great tool to assess the severity of nasal obstruction. In fact, the minimum and maximum degrees of obstruction to the RM after ND correlate significantly (p < 0.01) with those of NFE.

Green spruce aphid infestations cause larger growth reductions to Sitka spruce under shade.

Light availability and infestation by the green spruce aphid (Elatobium abietinum) are key factors affecting the growth of Sitka spruce (Picea sitchensis) seedlings under a mature tree canopy, but their combined effect on seedling growth has not previously been quantified. A controlled outdoor experiment in which light levels (high light (HL): 100%, intermediate light (IL): 24%) and aphid infestation (absence/presence) were manipulated was conducted over 2 years to look at the effects on seedling growth and biomass distribution patterns. Aphid population assessments showed a significantly increased population density under IL, with three to four times higher cumulative aphid densities than that under HL. Defoliation rates of infested seedlings were directly related to aphid density. Total seedling biomass was strongly reduced in IL, and aphid infestation caused additional reductions in the biomass of particular components of the seedlings. Dry weight (DW) of older (≥1-year-old) needles in infested trees was significantly decreased in both years. Total root DW at the end of the second year was significantly affected by aphid infestation, and the reduction (14-18%) was similar in IL and HL treatments despite large differences in aphid density. Biomass distribution patterns in infested trees were similar to that of uninfested trees within each light treatment, indicating that the relative decreases in root biomass were accompanied by similar reductions in distribution to the above-ground parts of the seedlings. Leader extension growth of infested seedlings was reduced by 15-17% compared with uninfested seedlings under IL, whereas only a 2-3% reduction in leader extension of infested seedlings under HL was observed. The results showed that the response of seedlings to E. abietinum were primarily dependent on the light environment. The significant reduction caused by aphids on the total DW of older needles and roots, and on leader extension growth, does suggest the potential for effects to accumulate over time.

Molecular differentiation of four Reptalus species (Hemiptera: Cixiidae).

The cixiid species Reptalus quinquecostatus, R. cuspidatus, R. panzeri and R. melanochaetus are widely distributed in Europe and are receiving growing attention because of their potential role as phytoplasma vectors. Identifying the Reptalus species is restricted to a few specialist entomologists and relies on the morphology of the male genitalia, hampering the identification of juveniles and females. This study provides the tools for species discrimination by integrating the morphological description, which is primarily for the genus identification, with new molecular assays, based on both ribosomal and mitochondrial DNA. PCR-RFLP assays carried out on the mitochondrial cytochrome oxidase I gene (COI) with AluI provided species-specific profiles for the four Reptalus species. Amplification of a ribosomal internal transcribed spacer (ITS2) region produced species-specific fragments of different sizes for R. quinquecostatus, R. melanochaetus, R. cuspidatus and R. panzeri. The digestion of the ITS2 PCR product with TaqI allowed the discrimination of these latter two species. This molecular identification key ensures reliable results and can be successfully applied not only to adults, but also to the nymphs feeding on the roots. The identification of the nymphs (i) extends the collection period of these monovoltine species to the whole year (adults are present for a short summer period) and (ii) allows the unambiguous identification of their actual host plants because nymphs are steady on the root system while adults tend to disperse onto other plants. Fast and reliable identification of the Reptalus species provides useful help in monitoring activities and, therefore, in designing rational control strategies to protect crops from phytoplasma infection.

Application of Classical Thermodynamics to Conductivity in Nonpolar Media: Experimental Confirmation.

We previously proposed ( Gourdin-Bertin , S. and Chassagne , C. J. Chem. Phys. 2016 , 144 ( 24) ) a simple theoretical model to account for the evolution of conductivity with dielectric permittivity in nonpolar media. In this article, we validate the theory experimentally for the case of an ionogenic species kept at a constant chemical potential (i.e., in equilibrium with a nondissolved salt, in contrast to previously published conductivity measurements carried out as a function of various fully dissolved salt concentrations). To our knowledge, it is the first time that this type of experiment has been performed explicitly.

Cellular and molecular events associated with the antitumor response induced by the cytosine deaminase/5-fluorocytosine suicide gene therapy system in a rat liver metastasis model.

The bacterial cytosine deaminase (CD) gene converts the non-toxic prodrug 5-fluorocytosine (5-FC) into 5-fluorouracil. We have previously shown, in a rat liver metastasis model from colon carcinoma, that intratumoral injection of a CD-expressing plasmid into the animals followed by 5-FC treatment results in the regression of the treated tumor as well as distant uninjected tumors. The aim of this study was to further analyze the mechanisms associated with tumor regression induced upon application of suicide CD/5-FC strategy. Tumor regression was associated with an increased apoptosis, the recruitment of natural killer cells, CD4- and CD8 T lymphocytes within the tumors and an increased expression of several cytokines/chemokines mRNAs. These data indicate that the CD/5-FC suicide strategy is associated with the triggering of cellular and molecular events leading to an efficient antitumor immune response involving both innate and acquired immunity.

Transmission of Grapevine virus A and Grapevine leafroll-associated virus 1 and 3 by Heliococcus bohemicus (Hemiptera: Pseudococcidae) Nymphs From Plants With Mixed Infections.

Mealybugs (Hemiptera: Pseudococcidae) represent a serious threat for viticulture as vectors of phloem-restricted viruses associated with the grapevine rugose wood and leafroll diseases. Heliococcus bohemicus (Sulc) is known to be involved in the spread of these two viral diseases, being a vector of the Grapevine virus A (GVA) and the Grapevine leafroll-associated virus 1 and 3 (GLRaV-1 and GLRaV-3). This study investigated the acquisition and transmission efficiency of H. bohemicus fed on mixed-infected plants. Nymphs were field-collected onto GVA, GLRaV-1, and GLRaV-3 multiple-infected grapevines in two vineyards in North-Western Italy, and were used in transmission experiments under controlled conditions. Even if most of the collected nymphs were positive to at least one virus, transmission occurred only to a low number of test grapevines. The transmission frequency of GLRaV-3 was the highest, whereas GVA was transmitted to few test plants. The transmission of multiple viruses occurred at low rates, and nymphs that acquired all the three viruses then failed to transmit them together. Statistical analyses showed that the three viruses were independently acquired and transmitted by H. bohemicus and neither synergistic nor antagonistic interactions occurred among them. GVA and GLRaVs transmission efficiencies by H. bohemicus were lower than those reported for other mealybug vectors. This finding is consistent with the slow spread of leafroll and rugose wood diseases observed in Northern Italy, where H. bohemicus is the predominant vector species.

Dual-specificity phosphatase 6 regulates CD4+ T-cell functions and restrains spontaneous colitis in IL-10-deficient mice.

Mitogen-activated protein kinase (MAPK) phosphatases are dual-specificity phosphatases (DUSPs) that dephosphorylate phosphothreonine and phosphotyrosine residues within MAPKs. DUSP6 preferentially dephosphorylates extracellular signal-regulated kinases 1 and 2 (ERK1/2) rendering them inactive. Here, we study the role of DUSP6 in CD4(+) T-cell function, differentiation, and inflammatory profile in the colon. Upon T-cell receptor (TCR) stimulation, DUSP6 knockout (Dusp6(-/-)) CD4(+) T cells showed increased ERK1/2 activation, proliferation, T helper 1 differentiation, and interferon-γ production, as well as a marked decrease in survival, interleukin- 17A (IL-17A) secretion, and regulatory T-cell function. To analyze the role of DUSP6 in vivo, we employed the Il10(-/-) model of colitis and generated Il10(-/-)/Dusp6(-/-) double-knockout mice. Il10(-/-)/Dusp6(-/-) mice suffered from accelerated and exacerbated spontaneous colitis, which was prevented by ERK1/2 inhibition. ERK1/2 inhibition also augmented regulatory T-cell differentiation in vitro and in vivo in both C57Bl/6 and Dusp6(-/-) mice. In summary, DUSP6 regulates CD4(+) T-cell activation and differentiation by inhibiting the TCR-dependent ERK1/2 activation. DUSP6 might therefore be a potential intervention target for limiting aberrant T-cell responses in T-cell-mediated diseases, such as inflammatory bowel disease.

TRPM8 on mucosal sensory nerves regulates colitogenic responses by innate immune cells via CGRP.

TRPM8 is the molecular sensor for cold; however, the physiological role of TRPM8+ neurons at mucosal surfaces is unclear. Here we evaluated the distribution and peptidergic properties of TRPM8+ fibers in naive and inflamed colons, as well as their role in mucosal inflammation. We found that Trpm8(-/-) mice were hypersusceptible to dextran sodium sulfate (DSS)-induced colitis, and that Trpm8(-/-) CD11c+ DCs (dendritic cells) showed hyperinflammatory responses to toll-like receptor (TLR) stimulation. This was phenocopied in calcitonin gene-related peptide (CGRP) receptor-deficient mice, but not in substance P receptor-deficient mice, suggesting a functional link between TRPM8 and CGRP. The DSS phenotype of CGRP receptor-deficient mice could be adoptively transferred to wild-type (WT) mice, suggesting that CGRP suppresses the colitogenic activity of bone marrow-derived cells. TRPM8+ mucosal fibers expressed CGRP in human and mouse colon. Furthermore, neuronal CGRP contents were increased in colons from naive and DSS-treated Trpm8(-/-) mice, suggesting deficient CGRP release in the absence of TRPM8 triggering. Finally, treatment of Trpm8(-/-) mice with CGRP reversed their hyperinflammatory phenotype. These results suggest that TRPM8 signaling in mucosal sensory neurons is indispensable for the regulation of innate inflammatory responses via the neuropeptide CGRP.

Quality assessment of combinatorial pooled libraries using mass spectrometry.

Parallel synthesis techniques aim to prepare collections of single compounds which, once tested, can easily be identified by their sole location in the synthesic array. On the other hand, true combinatorial chemistry produces libraries of compounds as mixtures of variable size which require a deconvolution procedure for identification of the active hits or leads. In the latter case, analytical methods are crucial for the success of the strategy and mass spectrometry plays a major role. If the goal is to identify all the library components, including expected products as well as by-products, various mass spectrometric techniques may be necessary. Library components can be separated according to their mass by increasing mass resolution or by their elution time by coupling liquid chromatography and mass spectrometry. The efficiency of such separation techniques are discussed as a function of the size and the degeneracy of the library. Library members possess common structural features which impart similar fragmentation patterns after ionization in the gas phase. This feature can be exploited by tandem mass spectrometry to specifically detect subfamilies of products. Examples of precursor ion scans, product ion scans and constant neutral loss scans will be shown that facilitate partial characterization of libraries. To solve the difficult problem of the quantitative analysis of libraries, i.e., to evaluate their equimolarity, the use of an evaporative light scattering detector (ELSD) or a chemiluminescent nitrogen detector (CLND) is suggested as more appropriate.

Involvement of the nucleus accumbens in the formation of spatial selection reactions in rats in a radial maze.

Studies on rats demonstrated that lesioning of the medial shell of the nucleus accumbens led to impairment of the ability of experimental rats to perform error-free identification of the arm containing the largest amount of reinforcement in a radial maze. The behavioral deficit was not associated with impaired motivation or sensorimotor learning ability, as there was no such deficit in operated rats during sequential presentation of local discriminant stimuli identifying the location of the forthcoming reinforcement. These data suggest that the medial shell of the nucleus accumbens, which receives convergent projections from the ventral hippocampus, amygdala, and ventral tegmental area, plays an important role in organizing the spatial orientation of the animal in the direction of the preferred reinforcement in conditions of a sensory information deficit.

Analysis of the action of the neuropeptide-inducing delta-sleep in cats and white rats.

Suboccipital administration of the oligopeptide to adult cats and white rats in a dose of 15 and 20 micrograms/kg induces the appearance of electrographic (delta-sleep) and behavioral sleep within 15-25 min. Administration of the oligopeptide induces a substantial increase in the thresholds of the response of the EEG to phonostimulation. A substantial lag (50-90 min) in the onset of paradoxical sleep is noted, which is considered by the authors as a manifestation of inhibition, exerted by the neuropeptide on the further development of the sleep mechanisms. On the basis of the data obtained it is concluded that natural sleep and that induced by the neuropeptide are nonequivalent.

[Simple retinal detachment: computer reconstruction of visual perception during the first month after surgery]. / Décollement de rétine simple: reconstruction informatique de la perception visuelle au cours du premier mois postopératoire.

Visual function during the first month following ab externo surgery for retinal detachment with raised macula has been inadequately investigated. We present through pictures the patient's perception of his visual function after surgical intervention consisting of cryotherapy, draining, scleral buckling, and gas. The patient used image processing software to modify the pictures seen by the nonoperated eye in order to reproduce his visual perception with the operated eye. Results show the relation between visual perception and clinical examination. When the surgical procedure is undergone early, visual recovery only requires a few days and color vision returns quickly. Hyalitis and gas perception prevails at first, then visual acuity increases progressively and efficiently.