University of Bremen

About: University of Bremen is a education organization based out in Bremen, Germany. It is known for research contribution in the topics: Population & Context (language use). The organization has 14563 authors who have published 37279 publications receiving 970381 citations. The organization is also known as: Universität Bremen.

Synthesis and Characterization

Abstract: As compared to bulk materials, magnetic nanoparticles possess distinct magnetic properties and attempts have been made to exploit their beneficial properties for technical and biomedical applications, e.g. for magnetic fluids, high-density magnetic recording, or biomedical diagnosis and therapy. Early magnetic fluids (MFs) were produced by grinding magnetite with heptane or long chain hydrocarbon and a grinding agent, e.g. oleic acid [152]. Later procedures for MFs precipitated Fe 3+/Fe 2+ of an aqueous solution with a base, coated the particles by oleic acid, and dispersed them in carrier liquid [161]. However, besides the elemental composition and crystal structure of the applied magnetic particles, particle size and particle size distribution determine the properties of the resulting MF. Many methods for nanoparticle synthesis including the preparation of metallic magnetic particles have been described in the literature. However, there still remain important questions, e.g. concerning control of particle size, shape, and monodispersity as well as their stability towards oxidation. Moreover, peptization by suitable surfactants or polymers into stable MFs is an important issue since each application in engineering or biomedicine needs special MFs with properties adjusted to the requirements of the system.

Transnationalization in international migration: implications for the study of citizenship and culture

Abstract: Terms such as transnational social spaces, transnational social fields or transnationalism usually refer to sustained ties of persons, networks and organizations across the borders across multiple nation-states, ranging from little to highly institutionalized forms. However, there are two large conceptual gaps in the study of transnational social spaces arising out of international migration and refugee flows. First, terms such as transnational social spaces and transnational communities are often used synonymously, as if 'transnational community' were the only form or type of transnational social space. This analysis outlines the primary mechanisms operative in transnationalization: reciprocity in small groups, exchange in circuits and solidarity in communities. These mechanisms correspond to distinct types of transnational social spaces - transnational kinship groups, transnational circuits and transnational communities. Second, the implications of transnationalization for citizenship and culture have n...