University of Fribourg

About: University of Fribourg is a education organization based out in Fribourg, Freiburg, Switzerland. It is known for research contribution in the topics: Population & Context (language use). The organization has 6040 authors who have published 14975 publications receiving 542500 citations. The organization is also known as: UNIFR & Universität Freiburg.

Rotaxanes as Mechanochromic Fluorescent Force Transducers in Polymers

Abstract: The integration of mechanophores, motifs that transduce mechanical forces into chemical reactions, allows creating materials with stress-dependent properties. Typical mechanophores are activated by cleaving weak covalent bonds, but these reactions can also be triggered by other stimuli, and this renders the behavior unspecific. Here we show that this problem can be overcome by extending the molecular-shuttle function of rotaxanes to mechanical activation. A mechanically interlocked mechanophore composed of a fluorophore-carrying macrocycle and a dumbbell-shaped molecule containing a matching quencher was integrated into a polyurethane elastomer. Deformation of this polymer causes a fluorescence turn-on, due to the spatial separation of fluorophore and quencher. This process is specific, efficient, instantly reversible, and elicits an easily detectable optical signal that correlates with the applied force.

Intercontinental spread of OXA-48 beta-lactamase-producing Enterobacteriaceae over a 11-year period, 2001 to 2011.

Abstract: OXA-48 beta-lactamase producers are emerging as an important threat mostly in the Mediterranean area. We report here the molecular epidemiology of a collection of OXA-48 beta-lactamase-positive enterobacterial isolates (n=107) recovered from European and north-African countries between January 2001 and December 2011. This collection included 67 Klebsiella pneumoniae, 24 Escherichia coli and 10 Enterobacter cloacae. Using the EUCAST breakpoints, ninety-eight isolates (91.6%) were of intermediate susceptibility or resistant to ertapenem, whereas 66% remained susceptible to imipenem. Seventy-five per cent of the isolates co-produced an extended-spectrum beta-lactamase, most frequently CTX-M-15 (77.5%). Susceptibility testing to non-beta-lactam antibiotics showed that colistin, tigecycline, amikacin, and fosfomycin remain active against most of the isolates. Multilocus sequence typing indicated that the most common sequence types (ST) were ST101 and ST38 for K. pneumoniae and E. coli, respectively. The bla(OXA-48) gene was located on a 62 kb IncL/M plasmid in 92.5% of the isolates, indicating that a single plasmid was mainly responsible for the spread of that gene. In addition, this study identified multiple cases of importation of OXA-48 beta-lactamase producers at least in Europe, and spread of OXA-48 beta-lactamase producers giving rise to an endemic situation, at least in France.

The Couples Coping Enhancement Training (CCET): A New Approach to Prevention of Marital Distress Based Upon Stress and Coping

Abstract: Programs for preventing marital distress and divorce have experienced an increasing interest among professionals and couples in the last few decades. This interest also is reflected in a growing number of publications on the effectiveness of these programs (e.g., Baucom, Shoham, Mueser, Daiuto, & Stickle, 1998; Halford, Markman, Kline, & Stanley, 2003). Most programs seek to help couples enhance their communication and problem-solving skills with the aim of improving the quality of their relationship, while also decreasing the likelihood of divorce (for an overview, see Berger & Hannah, 1999). These programs are mainly founded in social learning theories, humanistic theory, or communication theory and are based upon the knowledge that communication competencies are among the most important predictors of marital success (see meta-analysis by Karney & Bradbury, 1995). Within this body of empirical knowledge, a new line of research emerged in the 1990s, when different researchers began to investigate in greater detail the effects of stress and coping on marriage. Here we describe a distress prevention program for couples: Couples Coping Enhancement Training (CCET; Bodenmann, 1997b). We also report the findings from three research studies assessing program effectiveness.

Crystallization in three- and two-dimensional colloidal suspensions.

Abstract: Despite progress in the understanding of crystal nucleation and crystal growth since the first theories for nucleation were developed, an exact quantitative prediction of the nucleation rates in most systems has remained an unsolved problem. Colloidal suspensions show a phase behavior that is analogous to atomic or molecular systems and serve accordingly as ideal model systems for studying crystal nucleation with an accuracy and depth on a microscopic scale that is hard to reach for atomic or molecular systems. Due to the mesoscopic size of colloidal particles they can be studied in detail on the single-particle level and their dynamics is strongly slowed down in comparison with atomic or molecular systems, such that the formation of a crystal nucleus can be followed in detail. In this review, recent progress in the study of homogeneous and heterogeneous crystal nucleation in colloids and the controlled growth of crystalline colloidal structures is reviewed. All this work has resulted in unprecedented insights into the early stage of nucleation and it is also relevant for a deeper understanding of soft matter materials in general as well as for possible applications based on colloidal suspensions.