998 resultados para tRNA-derived fragments
Resumo:
Les cinquante-sept fragments rassemblés par Régis Jauffret présentent une suite de séquences de la vie de gens quelconques qui subissent l’existence comme un mal lancinant insupportable d’ennui, de solitude ou de promiscuité. Loin de proposer, comme le fait Philippe Delerm, une collection de vignettes des petits bonheurs ordinaires ou de rassembler, à la manière d’Annie Ernaux, des instantanés de la vie quotidienne collective révélateurs d’une époque, Jauffret fait défiler des fragments de vie qui, à force de s’additionner, perdent leurs contours distinctifs, se confondent les uns avec les autres et finissent par former un kaléidoscope monotone, indifférent, de la vie quotidienne des gens. La banalité de ces vies sans relief tient entre autres à la similitude des appartements, des rues, des situations aussi intenables les unes que les autres. Aucune vie, pourtant, n’est pareille aux autres, aucun parcours n’est exactement le même, mais tous sont pareillement ravalés dans l’uniformité de ce qui va, sans but, « quel que soit le chemin ». L’existence est insupportable mais on existe de toute façon, et ce sont toutes ces façons d’exister, sans nécessité, sans joie ni valeur ajoutée, que Jauffret accumule, exhibant jusqu’à saturation les vies banales de gens qui souffrent de toute façon, de toutes les façons. [Introduction]
Resumo:
Ce mémoire en recherche-création s’intéresse à la quête identitaire, et / ou au désir de tracer son propre chemin en réinterprétant les événements du passé. Le roman TRANSHUMANCES raconte le pèlerinage d’Alice sur la via Podiensis, qui relie la commune du Puy-en-Velay en France, à Santiago de Compostela en Espagne. Elle marche. Elle marche pour oublier, pour enterrer ses morts, pour avancer, ailleurs. Elle marche et fait de nombreuses rencontres. Par la conversation et la contemplation, elle tente d’apaiser les maux qui la rongent. Elle marche et apprivoise ce chemin mythique, mystique, cette route qui mène le croyant à la rencontre de Dieu et qui pousse l’impie à la rencontre de lui-même. Alice fait la connaissance de John. Ils se racontent des blagues et des secrets, partagent repas et larmes, deviennent frères d’ampoules et rentrent à la maison, changés. L’essai I ended up being my own trout (jeux de fragments avec Éric Plamondon) explore quant à lui à l’écriture fragmentaire, en s’intéressant particulièrement aux effets qu’opèrent les fragments sur la lecture. Éric Plamondon, avec sa trilogie 1984, utilise la forme fragmentaire afin de jouer avec le lecteur : il le fait douter de ses certitudes et le guide vers une vision manipulée de l’Histoire. Le lecteur est alors confronté à la pluralité des interprétations et doit s’imposer comme auteur de sa propre lecture.
Resumo:
The thesis deals with the synthesis, characterization and catalytic activity studies of supported cobalt(ii), nickel(II) and copper(II) complexes of O-phenylenediamine and Schiff bases derived from 3-hydroxyquinoxaline -2-carboxaldehyde. Zeolite encapsulation and polymer anchoring was employed for supporting the complexes. The characterization techniques proved that the encapsulation as well as polymer supporting has been successfully achieved. The catalytic activity studies revealed that the activities of the simple complexes are improved upon encapsulation. Various characterization techniques are used such as, chemical analysis, EPR, magnetic measurements, FTIR studies, thermal analysis, electronic spectra, XRD, SEM, surface area, and GC.The present study indicated that the that the mechanism of oxidation of catechol and DTBC by hydrogen peroxide is not altered by the change in the coordination sphere around the metal ion due to encapsulation. This fact suggests outer sphere mechanism for the reactions. The catalytic activity by zeolite encapsulated complex was found to be slower than that by the neat complex. The slowing down of the reaction in the zeolite case is probably due to the constraint imposed by the zeolite framework. The rate of DTBC ( 3,5-di-tert-butylchatechol)oxidation was found to be greater than the rate of catechol oxidation. This is obviously due to the presence of electron donating tertiary butyl groups.
Resumo:
The study deals with the diversity in structural and spectural characteristics of some transition metal complexes derived from aldehyde based thiosemicarbazone ligands thiosemicarbazones are a family of compounds with beneficial biological activity viz., anticancer,antitumour, antifungal, antibacterial, antimalarial, antifilarial, antiviral and anti-HIV activities. Many thiosemicarbazone ligands and their complexes have been prepared and screened for their antimicrobial activity against various types of fungi and bacteria. The results prove that the compounds exhibit antimicrobial properties and it is important to note that in some cases metal chelates show more inhibitory effects than the parent ligands. The increased lipophilicity of these complexes seems to be responsible for their enhanced biological potency. Adverse biological activities of thiosemicarbazones have been widely studied in rats and in other species. The parameters measured show that copper complexes caused considerable oxidative stress and zinc zinc complexes behaved as antioxidants. It has applications on analytical field also. Some thiosemicarbazones produce highly colored complexes with metal ions. This thesis aims to synthesis some novel thiosemicarbazone ligands and their transition metal complexes together with their physico-chemical characterization.
Resumo:
In this regard Schiff base complexes have attracted wide attention. Furthermore, such complexes are found to play important role in analytical chemistry, organic synthesis, metallurgy, refining of metals, electroplating and photography. Many Schiff base complexes are reported in literature. Their properties depend on the nature of the metal ion as well as on the nature of the ligand. By altering the ligands it is possible to obtain desired electronic environment around the metal ion. Thus there is a continuing interest in the synthesis of simple and zeolite encapsulated Schiff base complexes of metal ions. Zeolites have a number of striking structural similarities to the protein portion of natural enzymes. Zeolite based catalysts are known for their remarkable ability of mimicking the chemistry of biological systems. In view of the importance of catalysts in all the areas of modern chemical industries, an effort has been made to synthesize some simple Schiff base complexes, heterogenize them by encapsulating within the supercages of zeoliteY cavities and to study their applications. The thesis deals with studies on the synthesis and characterization of some simple and zeoliteY encapsulated Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes and on the catalytic activity of these complexes on some oxidation reactions. Simple complexes were prepared from the Schiff base ligands SBT derived from 2-aminobenzothiazole and salicylaldehyde and the ligand VBT derived from 2-aminobenzothiazole and vanillin (4-hydroxy-3- methoxybenzaldehyde). ZeoliteY encapsulated Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) complexes of Schiff base ligands SBT and VBT and also of 2-aminobenzothiazole were synthesized. All the prepared complexes were characterized using the physico-chemical techniques such as chemical analysis (employing AAS and CHN analyses), magnetic moment studies, conductance measurements and electronic and FTIR spectra. EPR spectra of the Cu(II) complexes were also carried out to know the probable structures and nature of Cu(II) complexes. Thermogravimetric analyses were carried out to obtain the information regarding the thermal stability of various complexes. The successful encapsulations of the complexes within the cavities of zeoliteY were ascertained by XRD, surface area and pore volume analysis. Assignments of geometries of simple and zeoliteY encapsulated complexes are given in all the cases. Both simple and zeoliteY encapsulated complexes were screened for catalytic activity towards oxidation reactions such as decomposition of hydrogen peroxide, oxidation of benzaldehyde, benzyl alcohol, 1-propanol, 2-propanol and cyclohexanol.
Resumo:
The Schiff base compounds N,N0-bis[(E)-quinoxalin-2-ylmethylidene] propane-1,3-diamine, C21H18N6, (I), and N,N0-bis[(E)- quinoxalin-2-ylmethylidene]butane-1,4-diamine, C22H20N6, (II), crystallize in the monoclinic crystal system. These molecules have crystallographically imposed symmetry. Compound (I) is located on a crystallographic twofold axis and (II) is located on an inversion centre. The molecular conformations of these crystal structures are stabilized by aromatic pye stacking interactions.
Resumo:
A novel bisazomethine Schiff base was synthesised by the condensation of 3-hydroxyquinoxaline-2- carboxaldehyde and 2,3-diaminomaleonitrile. 1H NMR, 13C NMR, HPLC and FT-IR studies revealed that the compound exists in two major tautomeric forms. The Schiff base exhibits positive absorption and fluorescent solvatochromism and displays dual fluorescence with large stoke shifts. Cyclic voltammetric analysis of the compound in 1:1 methanol–THF was influenced by scan rate. Thermal analysis of the compound was undertaken using TG–DTA and DSC
Studies on Some Transition Metal Complexes of Schiff Bases Derived from Quinoxaline-2-carboxaldehyde
Resumo:
Two series of transition metal complexes of Schiff bases derived from quinoxaline-2-carboxaldehyde with semicarbazide (QSC) and furfurylamine (QFA) were synthesised and characterised by elemental analyses, molar conductance and magnetic susceptibility measurements, IR, electronic and EPR spectral studies. The QSC complexes have the general formula [M(QSC)Cl2]. A tetrahedral structure has been assigned for the Mn(II), Co(II) and Ni(II) complexes and a square-planar structure for the Cu(II) complex. The QFA complexes have the formula [M(QFA)2Cl2]. An octahedral structure has been assigned for these complexes. All of the complexes exhibit catalytic activity towards the oxidation of 3,5-di-tert-butylcatechol (DTBC) to 3,5-di-tert-butylquinone (DTBQ) using atmospheric oxygen. The cobalt(II) complex of the ligand QFA was found to be the most active catalyst.
Resumo:
Some new transition metal complexes of the Schiff base quinoxaline-2-car boxalidene-2-aminophenol (HQAP) have been synthesized and characterized by elemental analyses, conductance and magnetic measurements and IR and UV-Visible spectral studies. The complexes have the following empirical formulae: [Mn(QAP121, [Fe(QAPl2C1I, [Co(QAPl21, [Ni(QAP121 and [Cu(QAP121. A tetrahedral structure has been assigned for the manganese(=), cobalt(II1, nickel(II1 and copper(II1 complexes. For the iron(IIIl complex an octahedral dimeric structure has been suggested