Controlled Growth of Dendrimer-Coated Gold Nanoparticles: A Solvent-Free Process in Mild Conditions

Monodisperse dendrimer-coated gold nanoparticles with a spherical shape have been obtained by direct reduction of HAuCl4 with sodium borohydride in the presence of dodecanethiol as a stabilizer and subsequent functionalization by ligand exchange reaction with polybenzylic thiolated dendrons. The substitution pattern of the dendrimeric units plays a fundamental role in the rate of the functionalization exchange process and consequently conditions the size and the polydispersity of the NPs obtained. An ulterior growth process occurs by thermal stimuli (150 °C) in a solvent-free environment. This method, carried out in mild conditions, allows the formation of highly monodisperse gold NPs with different sizes for different time reactions, and we discuss the mechanisms involved in this process. Finally, we demonstrate the chemical composition and stability of our compounds by structural, thermal, and chemical characterization of the samples before and after thermal treatment

Risk shifting consequences depending on manager characteristics

This paper investigates the performance consequences of the risk shifting behavior shown by domestic equity mutual funds through the analysis of monthly portfolio holdings. The objective of this paper is to assess the implications of risk shifting for mutual fund investors. Specifically, we study the performance consequences of different mechanisms of risk shifting, such as the change in the composition between equity and cash holdings and the change of the systematic or idiosyncratic risk within the equity positions. We find that funds that increase their risk level obtain significantly better performance than funds with stable or reduced risk levels. This finding is robust when controlling for fund characteristics such as past performance and fund size. Additionally, we examine whether the performance consequences of risk shifting depends on fund manager characteristics and find that manager gender, education and level of specialization are revealed as important variables to differentiate the performance consequences of risk shifting

Development of product design projects applying specificaions and factors matrix (SFM) as a support tool in higher education

The application of work strategies taking into account, from the initial stages, all the factors in- volved in the product design process is considered essential by the researches to generate higher quality products, assess users’ needs and anticipate design problems. This paper presents two approaches of design project development, denominated respectively: projects with imposed spe- cifications and projects with derived specifications and proposes the use of the matrix that inte- grates specifications and design factors (SFM). This design support tool complements others al- ready used in the development of product concepts by higher education students, increasing the capacity of synthesis and structuring of information in order to facilitate decision-making into the design process. Its elaboration implies understanding of objectives, identifying of factors and es- tablishing of specifications. At the same time, it aims to foster the reflection process and an inte- grated information analysis. The application of SFM and its contribution to different project ap- proaches are shown in this pape

Análisis integrado de especificaciones y factores en la realización de proyectos de diseño

Para disen~ar nuevos productos, competitivos y de alta calidad, o para mejorar los existentes, es necesario considerar todos los aspectos que intervienen en el proceso de desarrollo de producto y analizar co´mo e´stos afectan a las especificaciones iniciales. Este trabajo se centra en la investigacio´n y ana´lisis integrado de factores durante la realizacio´n de proyectos de disen~o industrial y muestra el estudio estructurado e interconectado de especificaciones y factores, aplicado al disen~o de dos dispositivos meca´nicos: un mando de freno y un aero´graf

Genetic analysis of microsatellites markers in two populations of Berrenda en Negro bovine breed

The Berrenda en Negro cattle breed has been used classically in the management of the fight bull and currently is found next their extinction. To contribute to the genetic conservation programs of this breed, we are characterized a sample of 32 animals with a panel of 15 microsatellites and we are provided data that permit, in a future, to compare its variability with other cattle breeds.La raza Bovina Berrenda en Negro se ha utilizado clásicamente en el manejo del toro de lidia y actualmente se encuentra próxima a su extinción. Para contribuir a los planes de recuperación genética de esta raza, se caracteriza una muestra de 32 animales con un panel de 15 microsatélites y se proporcionan datos que permitan, en un futuro, comparar su variabilidad con otras razas bovinas

The combination of halogen and hydrogen bonding: a versatile tool in coordination chemistry

4-Iodo-N-(4-pyridyl)benzamide (INPBA) and four derived coordination complexes were synthesized in order to explore the combination of halogen and hydrogen bonding interactions in coordination chemistry. An electron-withdrawing carbonyl group attached to the aromatic ring bearing an iodine atom has been introduced to increase its halogen bonding ability. Single crystal X-ray diffraction analyses ofINPBA, [Ag(INPBA)2]NO3(1), [ZnBr2(INPBA)2](2), [Zn(OCOPh)2(INPBA)2](3) and[HgI2(INPBA)]n(4) show the versatility of theINPBAbuilding block yielding a variety of different interesting structures. Iodine atom arrangement plays a key role by reinforcing and extending crystalline structures into diverse 3D supramolecular networksviaI¿O, I¿N, and I¿I halogen bonding interactions. Besides this, the overall supramolecular architecture of the coordination complexes is modulated by the N-H¿O, N-H¿Br, and C-H¿O hydrogen bonds formed by the carboxamide group. The combination of both, halogen and hydrogen bonds, allows very different coordination networks to be designed

High hole mobility and light-harvesting in discotic nematic dendrimers prepared: Via 'click' chemistry

We report a new family of liquid crystalline porphyrin-core dendrimers with coumarin units at the periphery of the dendrimer. These compounds have been prepared by copper-catalyzed azide-alkyne "click" cycloaddition (CuAAC). The mesomorphic properties have been investigated via polarized optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The peripheral coumarin units play a key role in the liquid crystal behavior, contributing to the appearance of discotic nematic mesophases with hole mobility values among the highest values reported for discotic liquid crystals (of the order of 1 cm 2 V -1 s -1 ). It has also been demonstrated that excitation of the coumarin moieties leads to energy transfer (antenna effect) to the luminescent porphyrin core. Therefore, this strategy, which involves ''click'' chemistry, has been proven to be a powerful and elegant synthetic tool for the preparation of optoelectronic materials based on complex dendritic architectures