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To succeed in Science on the Move, the nationwide competition for Swiss high school classes, students are requested to work as a team on relevant research topics. The project shapes their notion of science as one of the foundations of our society and as a possible professional field for themselves.

X-ray Computed Tomography (CT) combined with mechanical testing can deliver great insights in the damage mechanisms of polymers. Depending on the application area of the polymer, temperatures can be very high or low – leading to a different performance compared to room temperature. In this study, the influence of the temperature on damage mechanisms of a single particle in a polymer matrix should be investigated. Thus, three polymer tensile test specimens (length 30 mm; width 10 mm) – each containing a single particle – were cut out of a tape with a thickness of 0.5 mm and tested at various inspection temperatures. CT measurements were performed with the RX Solutions Easytom 160 laboratory CT device with a voxel size of (3 µm)³. Each specimen was scanned twice, namely at 0% strain and 30% strain. As inspection temperatures 0 °C, 22 °C and 60 °C were chosen. It is shown that temperature can have a great impact on the performance and damage mechanisms of a polymer, especially if a particle is present in the polymer matrix.

Após o fim da segunda guerra, a falta de mão de obra na Alemanha leva a acordos de migração com diferentes países para ocupação de postos de trabalho. Um grande contingente de migrantes provinha da Turquia. Nos anos 1950 e 60 a produção cultural turca não era perceptível pela sociedade alemã, mas surge aos poucos, nos anos subsequentes, em cabarets e filmes. A partir dos anos 1980 o teatro começa abordar a temática do migrante, mas sobretudo tratando do contexto sócio-cultural. O teatro juvenil abordava o tema da migração com clichês relativos à religião e à criminalidade juvenil. Só em 2008, quando Shermin Langhoff assumiu o teatro Ballhaus Naunynstrasse, em Berlim, o teatro passa a retratar a realidade social da Alemanha como país de imigração: os hábitos culturais do público e os pontos de vista convencionais são questionados por diretores e diretoras pós-migrantes, frequentemente já na terceira geração na Alemanha. Lentamente, o teatro profissional alemão se abre também para dramaturgos e atores de origem migrante.

As a first case in the field of spirochromenes, the energy barrier for thermally reversible ring opening of 2,2'-spirobichromenes (Scheme) is measured by racemization of preparatively enriched enantiomers. In addition, this barrier is estimated via racemization during HPLC (Fig.) on tribenzoylcellulose without preparative enrichment. The significance of the latter procedure is discussed.

The article discusses Juan and Antonio Cabezón's trip to Italy during the 16th century. The author reports that the two Spanish composers were able to meet with Italian musicians and study toccata's composition in particular. It is noted that both countries learned from each other about organ music.

The article discusses Spanish composers Antonio and Juan de Cabezón's trip to Italy during the 16th century. The author reports that the two organists had been able to meet Italian musicians and to learn from them, and to visit some of the great instruments of the country, including the one situated in San-Lorenzo.

Two families of nuclear receptors for retinoic acid (RA) have been characterized. Members of the RAR family (types alpha, beta and gamma and their isoforms alpha 1, alpha 2, beta 1 to beta 4, and gamma 1 and gamma 2) are activated by most physiologically occurring retinoids (all-trans RA, 9-cis RA, 4oxo RA and 3,4 dihyroRA). In contrast, members of the RXR family (types alpha, beta and gamma and their isoforms) are activated by 9cis-RA only. In addition to the multiplicity of receptors, the complexity of retinoid signalling is further increased by the fact that, at least in vitro, RARs bind to their cognate response elements as heterodimers with RXRs. Moreover, RXRs can also bind, in vitro, to some DNA elements as homodimers, and are heterodimeric partners for other nuclear receptors, including TRs, VDR, PPARs and a number of orphan nuclear receptors. To evaluate the functions of the different RARs and RXRs types and isoforms, we have generated null mutant mice by targeted gene disruption in ES cells. As to the functions of RARs, we found that RAR alpha 1 and RAR gamma 2 null mutant mice are apparently normal. Mice deficient in RAR alpha or RAR gamma (i.e., all alpha or gamma isoforms disrupted) show aspects of the post-natal vitamin A deficiency (VAD) syndrome which can be cured or prevented by RA, including post-natal lethality, poor weight gain and male sterility. RAR beta 2 (and RAR beta) null mutants display a retrolenticular membrane which represents the most frequent defect of the fetal VAD syndrome. That these abnormalities were restricted to a small subset of the tissues normally expressing these receptors suggested that some degree of functional redundancy should exist in the RAR family. To test this hypothesis we then generated RAR double null mutants. RAR alpha beta, RAR alpha gamma and RAR beta gamma compound mutants exhibit all the malformations of the fetal VAD syndrome, thus demonstrating that RA is the vitamin A derivative which plays a crucial role at many different stages and in different structures during organogenesis. Interestingly, almost all the structures derived from mesenchymal neural crests cells (NCC) are affected in RAR compound mutants. As to the functions of RXRs, RXR gamma null mutants are viable, fertile and morphologically normal. In contrast, RXR alpha null fetuses display a thin ventricular wall and die in utero from cardiac failure. A myocardial hypoplasia has also been observed in some RAR compound mutants as well as in VAD fetuses. Thus, RXR alpha seems to act as an inhibitor of ventricular cardiocyte differentiation and/or as a positive regulator of their proliferation, and these functions might involve heterodimerization with RARs and activation by RA. RXR beta null mutants are viable but the males are sterile, most probably because of an abnormal lipid metabolism in the Sertoli cells. New abnormalities, absent in RXR alpha mutants, are generated in RXR alpha/RAR (alpha, beta or gamma) compound mutants. All these abnormalities are also seen in RAR double mutants as well as in VAD fetuses. In contrast, such manifestations of synergism are not observed between the RXR beta or RXR gamma and the RAR (alpha, beta or gamma) null mutations. These data strongly support the conclusion that RXR alpha/RAR heterodimers represent the main functional units of the RA signalling pathway during embryonic development. Moreover, since RXR gamma-/-/RXR beta-/-/RXR alpha +/-mutants are viable, a single allele of RXR alpha can perform most of the developmental RXR functions.

Acute promyelotic leukemia is characterized by a t(15;17) chromosomal translocation which results in fusion products between PML (chromosome 15) and RAR-alpha (chromosome 17). We describe 2 classes of patients which possess different PMLRAR and RARPML fusion transcripts. We then discuss the functional properties of PML and show that PMLRAR can interfere with both PML and RAR-alpha functions.