Phytochemical profile and antioxidant properties of leaves extracts from Posidonia oceanica (L.) Delile and their allelopathic potential on terrestrial plant species

Dichloromethane, chloroform, ethyl acetate and ethanol extracts obtained from Posidonia oceanica (L.) leaves, were examined in order to determine their total phenolic, flavonoid, flavonol, anthocyanin and condensed tannins contents as well as their antioxidant and allelopathic activities. The qualitative phytochemical analysis of crude extracts confirmed the presence of coumarins in dichloromethane, chloroform and ethyl acetate extracts. The antioxidant activity estimated using the DPPH assay was significantly more pronounced for the ethyl acetate extract (IC50 = 1.19±0.018 mg/mL) than that of the other extracts. The allelopathic effect against the seeds of Carum carvi (L.) and Foeniculum vulgare (Mill.) indicated that, depending on concentration, the extracts from the leaves of P. oceanic (L.) inhibited or stimulated at different concentrations the germination, shoot and root elongation of seedlings growth. The results of this study suggest that P. oceanica (L.) extracts could be useful as a natural source of health-promoting effects and herbicides.                     KEY WORDS: Posidonia oceanic (L.), Phytochemical profile, Phenolic compounds, Antioxidant activity, Carum carvi (L.), Foeniculum vulgare (Mill)   Bull. Chem. Soc. Ethiop. 2020, 34(3), 437-447. DOI: https://dx.doi.org/10.4314/bcse.v34i3.

Présentation atypique d’une granulomatose avec polyangeite: à propos d’une observation pédiatrique

La granulomatose avec polyangéite (GPA) est une vascularite nécrosante systémique, caractérisée par une inflammation granulomateuse, une nécrose tissulaire et une vascularite touchant les vaisseaux de moyen et, surtout, de petit calibre, elle touche rarement l'enfant

Laryngectomie totale résultats de l’expérience du service d’orl de sfax

Introduction : La laryngectomie totale (LT) reste l’intervention la plus réalisée dans notre pays pour les cancers laryngés. Le but de ce travail est d’évaluer les résultats postopératoires et évolutifs des malades ayant eu une LT. Matériel et méthodes : Il s’agit d’une étude rétrospective à propos de 187 cas de patients ayant eu une laryngectomie totale, sur une période de 19 ans (1987-2005). La tumeur a été classée T3T4 dans 87,8 % des cas. L’atteinte des 3étages était trouvée dans 56% des cas et l’extension extra laryngée dans 59 % des cas. Une trachéotomie première pour dyspnée laryngée a été réalisée dans 44 % des cas. La laryngectomie était étendue au pharynx ou à la base de la langue dans 43 % des cas. Résultats : Les suites opératoires ont été marquées par l’apparition d'un  pharyngostome chez 19% des patients et par une infection dans 11% des cas. Les limites de résection ont été tumorales dans 14% des cas. Une radiothérapie postopératoire a été réalisée dans 92,5% des cas.Une rééducation orthophonique a pu être réalisée chez 36% des patients. Sur un recul moyen de 40 mois (2 à 132 mois), une récidive tumorale ou ganglionnaire a été retrouvée dans 8 % et 5 % des cas respectivement. Le taux de métastase à distance était de 11 % des cas. Une deuxième localisation a été objectivée dans 4 % des cas. La survie moyenne à 5 ans était de 75 %. Discussion : La laryngectomie totale est une intervention mutilante, par le handicap vocal qu’elle engendre mais la survie à 5 ans est de 75%. La perte définitive de la fonction phonatoire du larynx en constitue l’handicap majeur. Le diagnostic plus précoce de ces cancers dans notre pays peut permettre d’autres alternatives thérapeutiques.Mots-clés : Laryngectomie totale, pharyngostome, cancers laryngés

Hierarchical CO2-protective shell for highly efficient oxygen reduction reaction

The widespread application of intermediate-temperature solid oxide fuel cells is mainly being hurdled by the cathode's low efficiency on oxygen reduction reaction and poor resistance to carbon dioxide impurity. Here we report the fabrication of a hierarchical shell-covered porous cathode through infiltration followed by microwave plasma treatment. The hierarchical shell consists of a dense thin-film substrate with cones on the top of the substrate, leading to a three-dimensional (3D) heterostructured electrode. The shell allows the cathode working stably in CO2-containing air, and significantly improving the cathode's oxygen reduction reactivity with an area specific resistance of ∼0.13 Ωcm2 at 575°C. The method is also suitable for fabricating functional shell on the irregularly shaped substrate in various applications

General Relativity and Weyl Geometry

We show that the general theory of relativity can be formulated in the language of Weyl geometry. We develop the concept of Weyl frames and point out that the new mathematical formalism may lead to different pictures of the same gravitational phenomena. We show that in an arbitrary Weyl frame general relativity, which takes the form of a scalar-tensor gravitational theory, is invariant with respect to Weyl tranformations. A kew point in the development of the formalism is to build an action that is manifestly invariant with respect to Weyl transformations. When this action is expressed in terms of Riemannian geometry we find that the theory has some similarities with Brans-Dicke gravitational theory. In this scenario, the gravitational field is not described by the metric tensor only, but by a combination of both the metric and a geometrical scalar field. We illustrate this point by, firstly, discussing the Newtonian limit in an arbitrary frame, and, secondly, by examining how distinct geometrical and physical pictures of the same phenomena may arise in different frames. To give an example, we discuss the gravitational spectral shift as viewed in a general Weyl frame. We further explore the analogy of general relativity with scalar-tensor theories and show how a known Brans-Dicke vacuum solution may appear as a solution of general relativity theory when reinterpreted in a particular Weyl frame. Finally, we show that the so-called WIST gravity theories are mathematically equivalent to Brans-Dicke theory when viewed in a particular frame.Comment: LATEX, 22 page

Herschel-HIFI detections of hydrides towards AFGL 2591 (Envelope emission versus tenuous cloud absorption)

The Heterodyne Instrument for the Far Infrared (HIFI) onboard the Herschel Space Observatory allows the first observations of light diatomic molecules at high spectral resolution and in multiple transitions. Here, we report deep integrations using HIFI in different lines of hydrides towards the high-mass star forming region AFGL 2591. Detected are CH, CH+, NH, OH+, H2O+, while NH+ and SH+ have not been detected. All molecules except for CH and CH+ are seen in absorption with low excitation temperatures and at velocities different from the systemic velocity of the protostellar envelope. Surprisingly, the CH(JF,P = 3/2_2,- - 1/2_1,+) and CH+(J = 1 - 0, J = 2 - 1) lines are detected in emission at the systemic velocity. We can assign the absorption features to a foreground cloud and an outflow lobe, while the CH and CH+ emission stems from the envelope. The observed abundance and excitation of CH and CH+ can be explained in the scenario of FUV irradiated outflow walls, where a cavity etched out by the outflow allows protostellar FUV photons to irradiate and heat the envelope at larger distances driving the chemical reactions that produce these molecules.Comment: Accepted for publication in Astronomy and Astrophysics (HIFI first results issue

Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes

We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re

Rethinking justice beyond human rights. Anti-colonialism and intersectionality in the politics of the Palestinian Youth Movement

This article discusses the politics of the Palestinian Youth Movement (PYM) – a contemporary social movement operating across a number of Arab and western countries. Unlike analysis on the Arab Uprisings which focused on the national dimension of youth activism, we explore how the PYM politics fosters and upholds an explicitly transnational anti-colonial and intersectional solidarity framework, which foregrounds a radical critique of conventional notions of self-determination based on state-framed human rights discourses and international law paradigms. The struggle becomes instead framed as an issue of justice, freedom and liberation from interlocking forms and hierarchies of oppression. KEYWORDS: Palestine, transnational social movements, intersectionality, human rights, anti-colonialis

ATOMIUM: halide molecules around the S-type AGB star W Aquilae

Context. S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate but have not been studied in as much detail as their carbon- and oxygen-rich counterparts. W Aql is a nearby S-type star, with well-known circumstellar parameters, making it an ideal object for in-depth study of less common molecules. Aims. We aim to determine the abundances of AlCl and AlF from rotational lines, which have been observed for the first time towards an S-type AGB star. In combination with models based on PACS observations, we aim to update our chemical kinetics network based on these results. Methods. We analyse ALMA observations towards W Aql of AlCl in the ground and first two vibrationally excited states and AlF in the ground vibrational state. Using radiative transfer models, we determine the abundances and spatial abundance distributions of Al35Cl, Al37Cl, and AlF. We also model HCl and HF emission and compare these models to PACS spectra to constrain the abundances of these species. Results. AlCl is found in clumps very close to the star, with emission confined within 0′′.1 of the star. AlF emission is more extended, with faint emission extending 0′′.2 to 0′′.6 from the continuum peak. We find peak abundances, relative to H2, of 1.7 × 10−7 for Al35Cl, 7 × 10−8 for Al37Cl, and 1 × 10−7 for AlF. From the PACS spectra, we find abundances of 9.7 × 10−8 and ≤10−8, relative to H2, for HCl and HF, respectively. Conclusions. The AlF abundance exceeds the solar F abundance, indicating that fluorine synthesised in the AGB star has already been dredged up to the surface of the star and ejected into the circumstellar envelope. From our analysis of chemical reactions in the wind, we conclude that AlF may participate in the dust formation process, but we cannot fully explain the rapid depletion of AlCl seen inthe wind