ELECTROCHEMICAL BEHAVIOR AND ANALYSIS OF MONURON HERBICIDE IN WATER USING VOLTAMMETRIC METHODS AND PRE ACTIVATED CARBON PASTE ELECTRODE

This research work dealt with the electrochemical behavior and voltammetric analysis of monuron, a phenyl urea herbicide. The sensitive enhancement of the monuron electrochemical signal, using a pre-activated carbon paste electrode, and the explanation of its mechanism were the main findings of this study. Unlike most used herbicides (linuron, diuron, fenuron, etc), monuron was rarely studied before by electrochemical methods. Indeed the square wave voltammetry allowed to optimize and to analyze monuron in water samples; the results showed two linear ranges of concentration: from 1.98 to 0.39 µg mL-1 and from 0.35 to 0.08 µg mL-1, with detection and quantification limits of LOD= 0.016 µg mL-1 and LOQ= 0.054µg mL-1 respectively. Besides these quantitative results, the anodic oxidation of monuron has been explained by an irreversible adsorption-controlled process, following a “one electron – one proton” mechanism

Constitutive expression of clathrin hub hinders elicitor-induced clathrin-mediated endocytosis and defense gene expression in plant cells

AbstractEndocytosis has been recently implicated in the signaling network associated with the recognition of microbes by plants. In a previous study, we showed that the elicitor cryptogein was able to induce clathrin-mediated endocytosis (CME) in tobacco suspension cells. Herein, we investigate further the induced CME by means of a GFP-tagged clathrin light chain and a CME inhibitor, the hub domain of clathrin heavy chain. Hub constitutive expression does affect neither cell growth nor constitutive endocytosis but abolishes cryptogein-induced CME. Such an inhibition has no impact on early events in the cryptogein signaling pathway but reduces the expression of defense-associated genes

Noise spectra of K+ and NH4+ ions at over-limiting current in an electrochemical system with a cation exchange membrane

The present work investigates the effect of the counter ion nature on the noise of the over-limiting current (Iov). Moreover, the electrochemical methods, current voltage curve (I-V) and the chronopotentiometry (V-t) measurements are applied. The over-limiting current is always accompanied by a neat electrical noise. It is a well accepted experimental phenomenon. The study of this noise may contribute to a better understanding of the Iov and the feasibility of electrodialysis operation at this current in terms of energy consumption. The electrical noise depends directly on the counter ion nature. The power spectral density of the membrane's potential fluctuation was obtained via Fourier analysis of the time series recorded during the transport of counter ions (K+ and NH4+). The spectra are evaluated above the limiting current indicating the differences between the K+ and the NH4+. It is found that the cation NH4+ presents a singular behaviour and the noise is minimal

Movement‐assisted Sensor Deployment Algorithms: a Survey and Taxonomy

International audienceOne of the fundamental design issues in mobile wireless sensor networks is how to design efficient movement-assisted sensor deployment algorithms that relocate the sensor nodes in order to meet the desired performance goals. This survey focuses on a variety of movement-assisted sensor deployment algorithms that have been proposed and studied by researchers and highlights their strengths and limitations. The various models, assumptions, objectives, and constraints are identified, and the different formulations are enumerated. A taxonomy of movement-assisted sensor deployment algorithms that captures the fundamental differences among existing solutions is introduced. Six classes of approaches are identified, each one of them uses a specific principle to relocate the nodes from their initial position to a new target position. The proposed taxonomy is used to provide an exhaustive classification of existing approaches. For each identified class, various self-deployment algorithms are discussed. Furthermore, comparisons between the different algorithms and also between the different classes are performed, therefore providing not only a complete view of the state-of-the-art but also useful insights for selecting the self-deployment algorithm most appropriate to the application at hand. This paper also highlights open problems in this area of research

Ulcere de dieulafoy: une cause rare d’hemorragie digestive basse

L’ulcère de Dieulafoy est une cause rare d’hémorragie digestive en particulier l’hémorragie digestive basse. Nous rapportons dans cette observation un cas d’ulcère de Dieulafoy colique responsable d’une hémorragie digestive basse chez un sujet de 60 ans aux conditions de vie précaires, admis aux urgences de l’hôpital Saint-Louis de Paris. Le bilan initial comportant une rectosigmoidoscopie ainsi qu’une artériographie coeliomésentérique n’ayant pas permis de retrouver l’origine du saignement, une laparotomie exploratrice avec colectomie subtotale a été réalisée. L’examen histologique de la pièce opératoire avait montré au niveau de la paroi caecale une ulcération de la muqueuse et de la partie superficielle de la sous muqueuse, en regard d’une artère tortueuse et ectasique sous muqueuse, évoquant un ulcère de Dieulafoy. Cette observation illustre l’importance de l’examen histologique dans la prise en charge de cette lésion.Mots clés: Dieulafoy, hémorragie digestive basse, histopathologieEnglish Title: Dieulafoy disease: a rare cause of lower GI bleedingEnglish AbstractDieulafoy's ulcer is a rare cause of gastrointestinal bleeding in particular the lower gastrointestinal haemorrhage. We report in this observation a case of colonic Dieulafoy ulcer responsible for a lower gastrointestinal haemorrhage in a patient of 60 years, admitted to the emergency hospital of Saint Louis. Initial tests with arectosigmoidoscopy and a mesenteric arteriography laparoscopic did not reveal the source of bleeding, an exploratory laparotomy with subtotal colectomy was performed. Histological examination of the surgical specimen showed at the caecal wall an ulceration of the mucosa and superficial part of submucosa, associated with a tortuous and ectatic artery submucosa, suggesting a Dieulafoy ulcer. This case illustrates the importance of histology in the management of this lesion.Keywords: Dieulafoy, lower GI bleeding, histopatholog

TIP family aquaporins play role in chloroplast osmoregulation and photosynthesis

SUMMARYPhotosynthetic oxygen evolution by photosystem II requires water supply into the chloroplast to reach the thylakoid lumen. A rapid water flow is also required into the chloroplast for optimal oxygen evolution and to overcome osmotic stress. The mechanisms governing water transport in chloroplasts are largely unexplored. Previous proteomics indicated the presence of three aquaporins from the tonoplast intrinsic protein (TIP) family, TIP1;1, TIP1;2 and TIP2;1, in chloroplast membranes of Arabidopsis thaliana. Here we revisited their location and studied their role in chloroplasts. Localization experiments indicated that TIP2;1 resides in the thylakoid, whereas TIP1;2 is present in both thylakoid and envelope membranes. Mutants lacking TIP1;2 and/or TIP2;1 did not display a macroscopic phenotype when grown under standard conditions. The mutant chloroplasts and thylakoids underwent less volume changes than the corresponding wild type preparations upon osmotic treatment and in the light. Significantly reduced rates of photosynthetic electron transport were obtained in the mutant leaves, with implications on the CO2 fixation rates. However, electron transport rates did not significantly differ between mutants and wild type when isolated thylakoids were examined. Less acidification of the thylakoid lumen was measured in mutants thylakoids, resulting in a slower induction of delta pH-dependent photoprotective mechanisms. These results identify TIP1;2 and TIP2;1 as chloroplast proteins and highlight their importance for osmoregulation and optimal photosynthesis. A third aquaporin, TIP1;1, is present in the chloroplast envelope, and may play role in photosynthesis under excessive light conditions, as based on the weak photosynthetic phenotype of its mutant.</jats:p