249 research outputs found

    On Auxiliary Fields in BF Theories

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    We discuss the structure of auxiliary fields for non-Abelian BF theories in arbitrary dimensions. By modifying the classical BRST operator, we build the on-shell invariant complete quantum action. Therefore, we introduce the auxiliary fields which close the BRST algebra and lead to the invariant extension of the classical action.Comment: 7 pages, minor changes, typos in equations corrected and acknowledgements adde

    Rosiglitazone decreases postprandial production of acylation stimulating protein in type 2 diabetics

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    <p>Abstract</p> <p>Background</p> <p>We evaluated plasma ASP and its precursor C3 in type 2 diabetic men with/without rosiglitazone (ROSI) treatment compared to healthy non-obese men. We tested (1) whether plasma ASP or C3 are altered postprandially in subcutaneous adipose tissue or forearm muscle effluent assessed by arteriovenous (A-V) differences in healthy lean men and older obese diabetic men and (2) whether treatment with ROSI changes the arteriovenous gradient of ASP and/or C3.</p> <p>Methods</p> <p>In this ongoing placebo-controlled, crossover, double-blinded study, AV differences following a mixed meal were measured in diabetic men (n = 6) as compared to healthy men (n = 9).</p> <p>Results</p> <p>Postprandial arterial and adipose venous TG and venous NEFA were increased in diabetics vs. controls (p < 0.05–0.0001). ROSI treatment decreased postprandial arterial TG (p < 0.001), adipose venous NEFA (p < 0.005), reduced postprandial glucose (p < 0.0001) and insulin concentrations (p < 0.006). In healthy men, there was no change in postprandial C3, but an increase in adipose venous ASP vs. arterial ASP (p < 0.02), suggesting ASP production, with no change in forearm muscle. In older, obese diabetic subjects, arterial C3 was greater than in controls (p < 0.001). Arterial C3 was greater than venous C3 (p < 0.05), an effect that was lost with ROSI treatment. In diabetics, postprandial venous ASP was greater than arterial (p < 0.05), indicating ASP production, an effect that was lost with ROSI treatment (p < 0.01).</p> <p>Conclusion</p> <p>Increased postprandial venous production of ASP is specific for adipose tissue (absent in forearm muscle). Increased postprandial C3 and ASP in diabetic subjects is consistent with an ASP resistant state, this state is partially normalized by treatment with ROSI.</p

    Total Synthesis of a Mycolic Acid from Mycobacterium tuberculosis

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    In Mycobacterium tuberculosis, mycolic acids and their glycerol, glucose, and trehalose esters ("cord factor") form the main part of the mycomembrane. Despite their first isolation almost a century ago, full stereochemical evaluation is lacking, as is a scalable synthesis required for accurate immunological, including vaccination, studies. Herein, we report an efficient, convergent, gram-scale synthesis of four stereo-isomers of a mycolic acid and its glucose ester. Binding to the antigen presenting protein CD1b and T cell activation studies are used to confirm the antigenicity of the synthetic material. The absolute stereochemistry of the syn-methoxy methyl moiety in natural material is evaluated by comparing its optical rotation with that of synthetic material

    Modélisation 3D des façades de bùtiments des anciennes Médina

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    Le LIDAR (Light Detecting and Ranging) terrestre statique est un outil de levĂ© prĂ©sentant actuellement une source de donnĂ©es 3D indispensable dans l’évaluation et la surveillance des bĂątiments patrimoniaux. A travers des processus automatiques de modĂ©lisation 3D, la manipulation de cette source de donnĂ©es dans des outils de communication devient plus souple. Le processus de modĂ©lisation 3D impose des sous missions indispensables dont la segmentation. Une grande partie des approches de segmentation se focalisent sur l’emploi des composantes gĂ©omĂ©triques en exploitant la reprĂ©sentation mathĂ©matique d’une surface plane ou courbĂ©e. En raison de la complexitĂ© de l’architecture des façades, une segmentation utilisant uniquement l’aspect gĂ©omĂ©trique reste insuffisante. Ainsi, une nouvelle approche de segmentation est dĂ©veloppĂ©e Ă©quilibrant les rĂ©sultats de l’extraction des surfaces homogĂšnes. Ceci, en se basant sur l’ensemble des composantes d’un nuage de points coloriĂ©s Ă  savoir les composantes gĂ©omĂ©triques, les valeurs RGB et les intensitĂ©s laser des dĂ©tails constituant les façades des bĂątiments des anciennes MĂ©dina. Le processus s’initialise par l’extraction des segments plans Ă  l’aide de l’algorithme RANSAC. Le rĂ©sultat fera l’objet d’une deuxiĂšme segmentation radiomĂ©trique basĂ©e sur l’introduction du critĂšre de similaritĂ© couleur dans l’algorithme de croissance de rĂ©gion. Enfin une fusion de classes sera effectuĂ©e en fonction de la similaritĂ© de l’intensitĂ© laser. &nbsp; &nbsp;The static terrestrial LIDAR is a tool of surveying which present a vital source of 3D data in the heritage buildings evaluation and monitoring. Through automated &nbsp;3D modeling process, manipulating this data source in communication tools becomes more flexible. The 3D modeling process imposes on essential tasks including segmentation. Much of segmentation approaches focus on the use of geometric components by exploiting the mathematical representation of a plane or curved area. Due to the complexity of the facades architecture, segmentation using only the geometrical aspect is insufficient. Thus, a new segmentation approach is developed balancing the results of extracting homogeneous areas based on all colored point cloud components namely geometric data, the RGB values and intensities of facades details especially in old Medina building. The process consists of the planar segments extracting using the RANSAC algorithm. The result will be subject to radiometric segmentation through the introduction of color similarity criterion in the region growing algorithm and finally a fusion of classes based on the intensity’s similarity

    RĂ©partition des incendies de forĂȘts en fonction des facteurs physiques et biophysiques dans la RĂ©gion du Rif (Maroc)

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    L’évolution actuelle du rĂ©gime des incendies de forĂȘts pose de nouveaux dĂ©fis quant aux pratiques habituelles des plans d’amĂ©nagement et stratĂ©gies de gestion de ce flĂ©au. La mise en Ɠuvre d’actions de prĂ©vention et de lutte nĂ©cessite une comprĂ©hension fine de l’occurrence et de propagation des feux. Le prĂ©sent travail vise en une analyse spatio-temporelle des feux de forĂȘt en fonction des facteurs physiques et biophysiques dans la rĂ©gion du Rif au Maroc, considĂ©rĂ©e comme une des rĂ©gions les plus touchĂ©es par ce flĂ©au Ă  l’échelle nationale. Les incendies survenus dans cette rĂ©gion, entre 1997 et 2011, ont Ă©tĂ© analysĂ©s et classĂ©s en trois groupes de sĂ©vĂ©ritĂ© selon l’ampleur des superficies touchĂ©es. Cette analyse a montrĂ© que presque 80% des superficies incendiĂ©es ont Ă©tĂ© enregistrĂ©es durant les mois d’aoĂ»t et septembre. Par la suite, l’utilisation d’une analyse de variance dĂ©sĂ©quilibrĂ©e Ă  deux facteurs a permis de montrer la prĂ©sence d’une diffĂ©rence significative entre la sĂ©vĂ©ritĂ© de l’annĂ©e et les types de bioclimat, notamment pour les bioclimats Ă  hiver chaud caractĂ©risĂ©s par une production abondante de biomasse. Aussi, l’étude rĂ©vĂšle que pendant les annĂ©es sĂ©vĂšres, la vĂ©gĂ©tation des hautes altitudes devient plus vulnĂ©rable aux feux, particuliĂšrement pour les altitudes dĂ©passant 2000 m, en revanche, l’effet de la pente et de la continentalitĂ© n’est pas significatif et ne prĂ©sente aucune influence sur l’occurrence des feux

    Stereoselective Protection-Free Modification of 3-Keto-saccharides

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    Unprotected 3-keto-saccharides have become readily accessible via site-selective oxidation, but their protection-free functionalization is relatively unexplored. Here we show that protecting groups are obsolete in a variety of stereoselective modifications of our model substrate methyl α-glucopyranoside. This allows the preparation of rare sugars and the installation of click handles and reactive groups. To showcase the applicability of the methodology, maltoheptaose has been converted into a chemical probe, and the rare sugar evalose has been synthesized

    Tectonic evolution of the Eastern Moroccan Meseta: from Late Devonian fore‐arc sedimentation to Early Carboniferous collision of an Avalonian promontory

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    This study was founded by the Ministerio de Economia y Competitividad (MINECO) of Spain through the project PANGEATOR (CGL2015-71692-P) and the Doctoral scholarship BES-2016-078168. GeoHistory Facility instruments were funded via an Australian Geophysical Observing System grant provided to AuScope Pty Ltd. by the AQ44 Australian Education Investment Fund program. The NPII multicollector was obtained via funding from the Australian Research Council LIEF program (LE150100013). The authors want to express their gratitude to Dr. Manuel Francisco Pereira (University of Evora, Portugal) and Dr. Michel Villeneuve (Centre Europeen de Recherche et d'Enseignement des Geosciences de l'Environnement, France) for their constructive reviews that helped to improve the quality of the original manuscript. Special thanks to Brad McDonald (Curtin University, Australia) for technical assistance regarding LA-ICPMS and Hf analyses, Profs. Abdelfatah Tahiri (University Mohammed V of Rabat, Morocco) and Hassan El Hadi (University Hassan II of Casablanca, Morocco) for their support during field work, Prof. Yvette Kuiper (Colorado School of Mines, USA) for her precious hints about the interpretation of Hf data, and Dr. Lorenzo Valetti for proofreading the manuscript. Supporting information can be obtained in Mendeley Data: https://doi.org/10.17632/b8fdbykmbx.1 (https://data.mendeley.com/datasets/b8fdbykmbx/draft?a=eaae2da0-8e224056-861b-4824984f1c10).The deformed Paleozoic succession of the Eastern Moroccan Meseta crops out in relativelysmall and isolated inliers surrounded by Mesozoic and Cenozoic rocks. Two of the largest inliers(Mekkam and Debdou) are characterized by a monotonous succession of slates and greywackes affected bypolyphasic folding that occurred at low‐to very low grade metamorphic conditions. New U‐Pb ages ondetrital zircon grains from the Debdou‐Mekkam metasediments constrain the maximal depositional age asLate Devonian, interpreted to be close to the true sedimentation age. Furthermore, theΔHfvalues of theDevonian detrital zircons, together with the presence of a series of scattered zircon grains with ages betweenc. 0.9 and c. 1.9 Ga, suggest provenance from a subduction‐related magmatic arc located on the Avalonianmargin. The Debdou‐Mekkam massif is characterized by an Early Carboniferousfirst deformationalevent (D1), which gave way to a pervasive cleavage (S1) associated with plurikilometric‐scale, tight toisoclinal, overturned to recumbent folds. Later events (Dc) occurred at Late Carboniferous time andgenerated variably developed crenulation cleavages (Sc) associated with variously oriented metric‐tokilometric‐scale folds, which complicate the pattern of both D1 intersection lineations (L1) and axial traces.The restoration of this pronounced curved pattern yields originally SW‐NE‐oriented D1 fold axes withregional SE‐vergence. This important Early Carboniferous shortening and SE‐directed tectonic transport canbe explained by closure of the Rheic Ocean and thefirst phases of the collision between the northern passivemargin of Gondwana and an Avalonian promontory.Ministerio de Economia y Competitividad (MINECO) of Spain CGL2015-71692-P BES-2016-078168Australian Geophysical Observing SystemAustralian Education Investment Fund program AQ44Australian Research Council LE15010001

    Late-Stage Modification of Aminoglycoside Antibiotics Overcomes Bacterial Resistance Mediated by APH(3') Kinases

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    The continuous emergence of antimicrobial resistance is causing a threat to patients infected by multidrug‐resistant pathogens. In particular, the clinical use of aminoglycoside antibiotics, broad‐spectrum antibacterials of last resort, is limited due to rising bacterial resistance. One of the major resistance mechanisms in Gram‐positive and Gram‐negative bacteria is phosphorylation of these amino sugars at the 3’‐position by O‐phosphotransferases [APH(3’)s]. Structural alteration of these antibiotics at the 3’‐position would be an obvious strategy to tackle this resistance mechanism. However, the access to such derivatives requires cumbersome multi‐step synthesis, which is not appealing for pharma industry in this low‐return‐on‐investment market. To overcome this obstacle and combat bacterial resistance mediated by APH(3’)s, we introduce a novel regioselective modification of aminoglycosides in the 3’‐position via palladium‐catalyzed oxidation. To underline the effectiveness of our method for structural modification of aminoglycosides, we have developed two novel antibiotic candidates overcoming APH(3’)s‐mediated resistance employing only four synthetic steps

    T Cells Specific for a Mycobacterial Glycolipid Expand after Intravenous Bacillus Calmette-Guérin Vaccination

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    Intradermal vaccination with Mycobacterium bovis bacillus Calmette-Guérin (BCG) protects infants from disseminated tuberculosis, and i.v. BCG protects nonhuman primates (NHP) against pulmonary and extrapulmonary tuberculosis. In humans and NHP, protection is thought to be mediated by T cells, which typically recognize bacterial peptide Ags bound to MHC proteins. However, during vertebrate evolution, T cells acquired the capacity to recognize lipid Ags bound to CD1a, CD1b, and CD1c proteins expressed on APCs. It is unknown whether BCG induces T cell immunity to mycobacterial lipids and whether CD1-restricted T cells are resident in the lung. In this study, we developed and validated Macaca mulatta (Mamu) CD1b and CD1c tetramers to probe ex vivo phenotypes and functions of T cells specific for glucose monomycolate (GMM), an immunodominant mycobacterial lipid Ag. We discovered that CD1b and CD1c present GMM to T cells in both humans and NHP. We show that GMM-specific T cells are expanded in rhesus macaque blood 4 wk after i.v. BCG, which has been shown to protect NHP with near-sterilizing efficacy upon M. tuberculosis challenge. After vaccination, these T cells are detected at high frequency within bronchoalveolar fluid and express CD69 and CD103, markers associated with resident memory T cells. Thus, our data expand the repertoire of T cells known to be induced by whole cell mycobacterial vaccines, such as BCG, and show that lipid Ag-specific T cells are resident in the lungs, where they may contribute to protective immunity

    Evidence for surface uplift of the Atlas Mountains and the surrounding peripheral plateaux: Combining apatite fission-track results and geomorphic indicators in the Western Moroccan Meseta (coastal Variscan Paleozoic basement)

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    This work represents an initial attempt to link the evolution of the topography in relation to the general tectonic framework of western Morocco. For this purpose, in a section of the Western Moroccan Meseta different tools are combined in order to attain the general objective. Apatite fission-track (AFT) data of granitic rocks of the Rabat–Khenifra area give ages around 200 Ma with track length distributions which are compatible with the thermal models already established for the area. An inverse correlation between AFT ages and elevation is observed which is compatible with previous models indicating northward tilting of the whole Western Moroccan Meseta which is younger than 20–25 Ma. In order to test this possibility a detailed analysis of the topography at different scales in the Western Moroccan Meseta has been performed. Results indicate that two open folds with different amplitudes are recognized and that the one with wider wavelength could correspond to a lithospheric fold as previously stated by other authors on the basis of independent geological arguments. The northward tilting proposed based on the AFT data agrees with the results obtained in the analysis of the topography which reinforces the presence of a very open fold with a wavelength of 200–300 km in the north-western limb of the Western Moroccan Meseta
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