First-principles electronic structure of the delafossites ABO(2) (A=Cu, Ag, Au; B=Al, Ga, Sc, In, Y): evolution of d(10)-d(10) interactions

While bonding between d(10) atoms and ions in molecular systems has been well studied, less attention has been paid to interactions between such seemingly closed shell species in extended inorganic solids. In this contribution, we present visualizations of the electronic structures of the delafossites ABO(2) (A = Cu, Ag, Au) with particular emphasis on the nature of d(10)-d(10) interactions in the close packed plane of the coinage metal ion. We find that on going from Cu to Ag to Au, the extent of bonding between A and A increases. However, the structures (in terms of distances) of these compounds are largely determined by the strongly ionic 13,11 0 interaction and for the larger B ions Sc, In and Y, the A atoms are sufficiently well-separated that A-A bonding is almost negligible. We also analyze some interesting differences between Ag and Au, including the larger A-O covalency of the Au. The trends in electronic structure suggest that the Ag and Au compounds are not good candidate transparent conducting oxides. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.

Novel ABO(3) oxides related to perovskite and YAlO3 structure types in the La-B-V-O (B = Ni, Cu) systems

The synthesis, structure and magnetic properties of mixed-metal oxides of ABO(3) composition in the La-B-V-O (B = Ni, Cu) systems are described in the present paper. While the B = Ni oxides adopt GdFeO3-like perovskite structure containing disordered nickel and vanadium at the octahedral B site, La3Cu2VO9 crystallizes in a YAlO3-type structure. A detailed investigation of the superstructure of nominal La3Cu2VO9 by WDS analysis and Rietveld refinement of powder XRD data reveal that the likely composition of the phase is La13Cu9V4O38.5, where the Cu and V atoms are ordered in a root13a(h) (a(h) = hexagonal a parameter of YAlO3-like subcell) superstructure. Magnetic susceptibility data support the proposed superstructure consisting of triangular Cu-3 clusters. At low temperatures, the magnetic moment corresponds to S = 1/2 per Cu-3 cluster, while at high temperatures the behavior is Curie-Weiss like, showing S = 1/2 per copper. The present work reveals the contrasting behavior of La-Cu-V-O and La-Ni-V-O systems: while a unique line-phase related to YAlO3 structure is formed around La3Cu2VO9 Composition in the copper system, a continuous series of perovskite-GdFeO3 solid solutions, LaNi1-xVxO3 for 0 less than or equal to x less than or equal to 1/3 seems to be obtained in the nickel system, where the oxidation state of nickel varies from 3+ to 2+.

The relationship between the thermal expansions and structures of ABO(4) oxides

The linear thermal expansion coefficients of ABO(4) compounds are determined and the expansion tendency is analyzed from the chemical bond viewpoint. All chemical bonds contributions are involved. The contributions from different chemical bonds are compared with each other and the origin of the expansion behavior of ABO(4) oxides is revealed that the A-O bonds expansions dominate the compound expansion. The calculated expansion coefficients agree satisfactorily with the experimental data. By analyzing the expansion regularity the range of the expansion coefficients can be qualified. The thermal expansion coefficients of some ABO(4) compounds having not been measured are predicted and discussed.

Studies on the adsorption property of NO on the Ni-based mixed oxide catalysts with Perovskite-like (ABO(3) and A(2)BO(4)) structure

The mixed oxides LaNiO3, La0.1Sr0.9NiO3, La2NiO4 and LaSrNiO4 with perovskite (ABO(3)) and related(A(2)BO(4)) structures were prepared and the adsorption property for NO and the catalytic activity for NO decomposition over these oxidse were also tested. The catalysts were characterized by means of BET surface measurement, chemical analysis, NO-TPD etc.. It was shown that the adsorption amount of NO is correlated with the concentration of oxygen vacancy formed and the adsorption type and strength of NO are related to the valence of metallic ion. Generally there are three kinds of adsorption species, NO-, NO+ and NO on the mixed oxides, among them the negative adsorpion species (NO-) are active for NO decomposition. The weaker the adsorption of oxygen on the catalyst is, the faster the mobility of oxygen is and the easier the redox process takes place in reproducing the active sites in which the oxygen species (O-, O2-) would participate.

Aislamiento y purificación del antígeno A del sistema ABO,mediante la columna cromatográfica de afinidad

Tesis (Maestría en Ciencias, con especialidad en Inmunología) U.A.N.L.

Frecuencias de grupos sanguíneos ABO, Rho (D) Mn. e isominia en personas con apellidos mono y polifiléticos del área metropolitana de Monterrey, Nuevo León [por] Ma. de los Angeles Rojas Alvarado

Tesis (Maestro en Ciencias con especialidad en Genética)

Asociación del grupo sanguíneo ABO con el riesgo de diabetes mellitus tipo 2 en adultos sin el diagnóstico de la enfermedad.

Tesis (Maestría en Ciencias de Enfermería) UANL, 2014.

La regi??n asturiana : Elementos b??sicos para su estudio. Trabajo de campo : zona costera central Avil??s-Abo??o

El objetivo de este trabajo es poner al alumno en contacto con la realidad de su entorno geogr??fico y natural. Se han seleccionado los enfoques acad??micos e interdisciplinares propios de la Geograf??a e Historia y de las Ciencias Naturales. El trabajo se compone de dos partes, en la primera se estudian aspectos b??sicos de tipo te??rico como morfolog??a, geolog??a de la zona, clima... y en la segunda el trabajo de campo propiamente dicho en el que se hace el itinerario entre Avil??s y Abo??o con la historia de la zona, contaminaci??n y el estudio descriptivo de todo el recorrido. El trabajo en el aula se debe realizar impartiendo determinada cantidad de conceptos seg??n los niveles y en un orden de sucesi??n preestablecido. El instrumento b??sico de este proyecto educativo es el trabajo de campo, recurso que ha de estar contextualizado para que sirva como medio en la obtenci??n de un fin. Se trata de aprehender un trozo de realidad, vivir una situaci??n, captar una parte del medio ambiente. El trabajo de campo no es un acto did??ctico aislado, sino la fase central de un proceso que se inicia en el aula y termina en ella. Se utiliza una terminolog??a t??cnica como intento de superaci??n del nivel intelectual de los alumnos, tambi??n se unen otros t??rminos m??s coloquiales para proporcionar explicaciones m??s inteligibles de algunos procesos. Se ofrecen adem??s unas recomendaciones para que el trabajo expuesto sirva de gu??a o instrumento para profesores que lo quieran adaptar a otros niveles o a otros itinerarios.

La regi??n asturiana : elementos b??sicos para su estudio. Trabajo de campo : zona costera central Avil??s-Abo??o. Trabajo sobre el medio ambiente y el entorno asturiano

El trabajo consiste en elaborar 'viajes culturales' o 'salidas al campo' con objetivos did??cticos y realizar aut??nticas gu??as de estudio sobre itinerarios. Se trata de utilizar las posibilidades educativas que tiene el medio ambiente que rodea al alumno con un enfoque integrador e interdisciplinar en distintos itinerarios. Se ha pensado en la zona central pues presenta un elevado inter??s, paisaje natural que debido a la industria ha sufrido grandes transformaciones y, adem??s, corresponde a un ??rea de alta densidad demogr??fica. M??todo: estudio bibliogr??fico sobre las zonas del itinerario, salidas al campo y estudio directo sobre la zona, las salidas de la primera fase se har??an entre Avil??s y Gij??n, en el proyecto vienen reflejados los bienes del equipo, el presupuesto estimado, etc... La realizaci??n del trabajo es fruto de un proyecto inicial del que se han seleccionado los enfoques acad??micos e interdisciplinares propios de la Geograf??a e Historia y las Ciencias Naturales. La memoria del proyecto se public?? en la colecci??n Dayures Materiales Did??cticos n??mero 1. Los autores del trabajo pertenencen al Grupo interdiciplinar del medio ambiente y del entorno del CEP de Oviedo.

Estudio de las frecuencias de los alelos del sistema ABO en la provincia de Pontevedra.

Estudio de las diferentes frecuencias genéticas en los grupos sanguíneos conocidos, como ABO y Rh, entre otros, de la población gallega para compararlas con las de otras poblaciones afines como la irlandesa, la galesa o los bretones.

Association of ABO gene mutations resulting in a rare B subgroup

Background and Objectives B subgroups are rare and the genetic analysis reported to date has been limited.Materials and Methods Serological and molecular investigations were performed in blood from a B-subgroup donor.Results Red cells did not react with anti-B and anti-AB reagents. However, cells absorbed anti-B. Red cells presented positive reactions with anti-H, and saliva secreted H substance. The molecular study demonstrated a B allele with the substitutions 467C>T, 646T>A, 681G>A, 771C>T, 796C>A, 803G>C, 829G>A and an 0 allele with the sequence of 002.Conclusions It is probable that the presence in exon 7 of some of the 002 substitutions could have weakened the enzymatic activity of the encoded B transferase.

Dermatophytosis: association between ABO blood groups and reactivity to the trichophytin

Os autores investigaram a relação entre dermatofitose e grupo sanguíneo ABO através da tipagem sanguínea, identificação do dermatófito isolado e resposta imune celular específica de 40 indivíduos portadores desta micose. Verificaram que o fungo Trichophyton rubrum foi isolado em 54,5% dos pacientes, sendo mais frequente em indivíduos pertencentes ao grupo sanguíneo A. A resposta imune celular, avaliada através do antígeno tricofitina, foi positiva em 25% dos pacientes estudados; a presença de reações imediatas (30 min) foi verificada em 35%. A distribuição dos grupos sanguíneos entre pacientes com dermatofitose e grupo controle foi a seguinte: 47,5% x 36% grupo A, 40% x 50% grupo O, 12,5% x 11% grupo B. Embora os autores tenham encontrado um número maior de pacientes pertencentes ao grupo sanguíneo A e infectados pelo T. rubrum, não obtiveram evidência estatística de que esses indivíduos sejam mais suscetíveis as dermatofitoses.

Lack of association between ABO histo-blood groups, secretor and non-secretor phenotypes, and anti-Toxoplasma gondii antibodies among pregnant women from the northwestern region of São Paulo State, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)