Electrochemical, spectroscopic and SPM evidence for the controlled formation of self-assembled monolayers and organised multilayers of ferrocenyl alkyl thiols on Au(111)

Organised multilayers were formed from the controlled self-assembly of ferrocene alkyl thiols on Au(111) surfaces. The control was accomplished by increasing the concentration of the thiol solutions used for the assembly. Cyclic voltammetry, ellipsometry, scanning probe microscopy (STM and AFM) and in situ FTIR spectroscopy were used to probe the differences between mono- and multilayers of the same compounds. Electrochemical desorption studies confirmed that the multilayer structure is attached to the surface via one monolayer. The electrochemical behaviour of the multilayers indicated the presence of more than one controlling factor during the oxidation step, whereas the reduction was kinetically controlled which contrasts with the behaviour of monolayers, which exhibit kinetic control for the oxidation and reduction steps. Conventional and imaging ellipsometry confirmed that multilayers with well-defined increments in thickness could be produced. However, STM indicated that at the monolayer stage, the thiols used promote the mobility of Au atoms on the surface. It is very likely that the multilayer structure is held together through hydrogen bonding. To the best of out knowledge, this is the first example of a controlled one-step growth of multilayers of ferrocenyl alkyl thiols using self-assembly techniques.

Anisotropic Deformation Of Polystyrene Particles By Mev Au Ion Irradiation

MeV An irradiation leads to a shape change of polystyrene (PS) and SiO2 particles from spherical to ellipsoidal, with an aspect ratio that can be precisely controlled by the ion fluence. Sub-micrometer PS and SiO2 particles were deposited on copper substrates and irradiated with Au ions at 230 K, using an ion energy and fluence ranging from 2 to 10 MeV and 1 x 10(14) ions/cm(2) to 1 x 10(15) ions/cm(2). The mechanisms of anisotropic deformation of PS and SiO2 particles are different because of their distinct physical and chemical properties. At the start of irradiation, the volume of PS particles decrease, then the aspect ratio increases with fluence, whereas for SiO2 particles the volume remains constant. (C) 2008 Elsevier B.V. All rights reserved.

Influence Of Different Amount Of Au On The Wetting Behavior Of Pdms Membrane

Polydimethylsiloxane (PDMS) has been widely used as a base material for bio-MEMS/NEMS devices. It is difficult for PDMS to transfer and spread aqueous solution as a kind of highly hydrophobic material. Therefore, surface modification is necessary for PDMS to make it hydrophilic. In this paper, a method of hydrophilization of PDMS surface is proposed. Gold is sputtered to the PDMS substrate by sputter coater in different average thicknesses. Relationship between the average thickness of gold on the PDMS substrate and the contact angle of the surface was studied. It was found that even gold of average thickness less than 1 nm can result in about 25 degrees change of contact angle. AFM is also used to get topographic information of PDMS surface coated with gold. Three cases are classified with different amount of Au: (1) Heterogeneous zone; (2) Transition zone; (3) Film zone. For heterogeneous zone, a simple model about heterogeneous phase wetting is put forward to interpret this phenomenon.

La souffrance émotionnelle des personnels d’intervention : résultats préliminaires de l’étude sur la santé et la qualité de vie au travail dans les métiers du secteur de l’aide et du soin à domicile

Resumen: La prolongación de la edad y el aumento de la expectativa de vida han hecho surgir nuevas necesidades de atención para las personas ancianas y ello ha inducido a la ampliación de las prestaciones de servicios a domicilio. En este sentido, el trabajo de estos profesionales de intervención a domicilio, así como sus misiones, están en plena mutación. Es un sector con dificultades, debido a la dificultad de reclutar un personal especializado y al absentismo inquietante. Después de un análisis sobre el estado de este sector de la profesión en el que se establece la diferencia entre el enfoque físico y el psicológico sobre la salud, nuestra reflexión se centra en los riesgos psicosociales de esta población de profesionales. Se presentan los resultados preliminares de la investigación realizada con una muestra de 38 personas que ejercían laboralmente en este sector. Emerge la expresión de un sufrimiento emocional, en la que el aislamiento de los participantes es uno de los factores que caracterizan los oficios identificados con una fuerte dimensión relacional con personas vulnerables. La dimensión asistencial del trabajo se presenta como fuente de satisfacción del oficio pero, a su vez, puede conducir a una dificultad de gestionar acontecimientos no previstos

Adsorption of His-tagged peptide to Ni, Cu and Au (100) surfaces: Molecular dynamics simulation

Molecular dynamics (MD) simulations are performed to study the interaction of His-tagged peptide with three different metal surfaces in explicit water. The equilibrium properties are analyzed by using pair correlation functions (PCF) to give an insight into the behavior of the peptide adsorption to metal surfaces in water solvent. The intermolecular interactions between peptide residues and the metal surfaces are evaluated. By pulling the peptide away from the peptide in the presence of solvent water, peeling forces are obtained and reveal the binding strength of peptide adsorption on nickel, copper and gold. From the analysis of the dynamics properties of the peptide interaction with the metal surfaces, it is shown that the affinity of peptide to Ni surface is the strongest, while on Cu and An the affinity is a little weaker. In MD simulations including metals, the His-tagged region interacts with the substrate to an extent greater than the other regions. The work presented here reveals various interactions between His-tagged peptide and Ni/Cu/Au surfaces. The interesting affinities and dynamical properties of the peptide are also derived. The results give predictions for the structure of His-tagged peptide adsorbing on three different metal surfaces and show the different affinities between them, which assist the understanding of how peptides behave on metal surfaces and of how designers select amino sequences in molecule devices design. (c) 2007 Elsevier Ltd. All rights reserved.

Le pays du café : voyage de M. Durand au Brésil

Trata da viagem de M. Durand ao Brasil, esboçada em dez capítulos que retratam aspectos culturais e geográficos do Brasil no século XIX.

Relations veritables et curieuses de l'isle de Madagascar et du Bresil : avec l'histoire de la derniere guerre faite au Bresil, entre les portugais & les hollandois : trois relations d'Egypte, e une du royaume de Perse

‘Relations veritables et curieuses de l'Isle de Madagascar, et du Bresil’, de responsabilidade do livreiro Augustin Courbé, foi redigida em parte por Morisot, de DiJon, com base em documentos fornecidos pelos irmãos Dupuy. A obra, composta por dois volumes reunidos em um tomo, contém diversos relatos. Muita confusão existe acerca dessa edição de Courbé, seja relativamente ao número de volumes da obra, seja quanto à autoria dos relatos. Borba de Moraes a firma que "esses erros decorrem da raridade do trabalho completo". O primeiro volume, apresentado sob o titulo geral ‘Relations veritables et curieuses de l’Isle de Madagascar, et du Bresil’, contém os trabalhos ‘Relation du voyage de François Couché...: De la religion, moeurs, et façons de faire de ceux de I'Lsle de Madagascar: colloque entre le madagascarois et le françois...’, e ‘Re1ation du voyage de Roulox Baro’. O segundo volume é intitulado ‘Histoire des derniers troubles du Bresil entre les hollandois et les portugais’ e foi escrito por Pierre Moreau, cujo texto ocupa as 212 páginas iniciais. Além deste, constam do volume ‘Trois relations d'Egypte et autres memoires...’ e a ‘Relation d'um voyage de Perse’. Prod uzida a partir da observação dos fatos ocorridos durante o período de sua permanência em Pernambuco durante a ocupação pelos holandeses, a obra de Moreau é de capital importância para o estudo da situação socioeconômica de Pernambuco sob o domínio holandês. A edição de A. Courbé, conhecido livreiro que se estabeleceu em Paris de 1629 a 1660, teve o projeto das ilustrações a cargo de Jean Picard, oriundo de uma famosa família de gravadores, cujo nome aparece no primeiro volume apenas, segundo Borba de Moraes

Voisinage et hábitat dans les communautés des Pyrénées Occidentales entre le XV et le XVIIIe siècles : de la croissance au blocage

Publicado dentro de la colección «Méridiennes» (ISSN: 1950-0130)

Reflexions critiques sur les histoires des anciens peuples, chaldeens, hebreux, pheniciens, egyptiens, grecs, & c. jusq'au tems de cyrus, en trois livres

Examina fragmentos da história fenícia, a mitologia e a origem dos deuses egípcios, gregos e fenícios. Explica as dificuldades cronológicas do Antigo Testamento, da história do Egito, da Babilônia, da Assíria, da Grécia e da China. No final traz uma cronologia do império chinês, com os nomes do imperadores em letras latinas e caracteres chineses.

Quebec's "écriture au féminin" and translation politicized

Eguíluz, Federico; Merino, Raquel; Olsen, Vickie; Pajares, Eterio; Santamaría, José Miguel (eds.)

Voyage au Bresil : ou l'on trouve la description du pays, de ses productions, de ses habitants, et de la ville et des provinces de san-salvatore et porto-seguro, avec une table correcte des latitudes et longitudes des ports de la cote du bresil, ainsi qu'un tableau du change, etc

Voyage au Brésil narra a experiência de observar a vida e os costumes dos habitantes do Brasil e oferece um registro cheio de interesse sociológico e até científico. Segundo Rubens Borba de Moraes, " é obra valiosíssima sobre a Bahia colonial", sendo esta edição mais preciosa que a inglesa de 1805. A obra foi traduzida também para o alemão. Afonso de Taunay resume e comenta o livro de Lindley em Aventuras de Thomas Lindley.

Les jeunes face au marché du travail en France: entre difficultés d´insertion et stratégies de pénétration

En une génération, entre 1975 et 1995, le paysage du marché du travail auquel les jeunes font face a radicalement changé.