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Université de Fribourg

Photo-crosslinked side-chain liquid-crystalline elastomers for microsystems

Sánchez-Ferrer, Antoni ; Fischl, Tamás ; Stubenrauch, Mike ; Wurmus, Helmut ; Hoffmann, Martin ; Finkelmann, Heino

In: Macromolecular Chemistry and Physics, 2009, vol. 210, no. 20, p. 1671-1677

Photo-crosslinkable side-chain liquid-crystalline polymers (LCPs) containing photoreactive benzophenone cores are synthesized in order to obtain their corresponding side-chain liquid-crystalline elastomers (LCEs). This strategic synthesis allows thin elastomeric films and their integration into microsystems for actuators and micromachines to be obtained. As an example of this principle, a gripper...

Université de Fribourg

Mechanical deformations in smectic-C main-chain liquid-crystalline elastomers

Sánchez-Ferrer, Antoni ; Finkelmann, Heino

In: Molecular Crystals and Liquid Crystals, 2009, p. 357-366

A novel crosslinked smectic-C Main-Chain Liquid-Crystalline Elastomer (MCLCE) has been synthesized by polycondensation of vinyloxy-terminated mesogens, tetramethyldisiloxane and pentamethylpentaoxapentasilecane. The introduction of the functional vinyloxy group allows the synthesis of well-defined networks having low soluble content and good mechanical properties. Networks having a macroscopic...

Université de Fribourg

Structure-preserving desynchronization of minority games

Mosetti, Giancarlo ; Challet, Damien ; Solomon, S.

In: The European Physical Journal B, 2009, vol. 71, no. 4, p. 573-577

Perfect synchronicity in N-player games is a useful theoretical dream, but communication delays are inevitable and may result in asynchronous interactions. Some systems such as financial markets are asynchronous by design, and yet most theoretical models assume perfectly synchronized actions. We propose a general method to transform standard models of adaptive agents into asynchronous systems...

Université de Fribourg

Extracellular matrix controls insulin signaling in mammary epithelial cells through the RhoA/Rok pathway

Lee, Yi-Ju ; Hsu, Tsai-Ching ; Du, Jyun-Yi ; Valentijn, Anthony J. ; Wu, Tung-Yi ; Cheng, Cheng-Fu ; Yang, Zhihong ; Streuli, Charles H.

In: Journal of Cellular Physiology, 2009, vol. 220, no. 2, p. 476-484

Cellular responses are determined by a number of signaling cues in the local microenvironment, such as growth factors and extracellular matrix (ECM). In cultures of mammary epithelial cells (MECs), functional differentiation requires at least two types of signal, lactogenic hormones (i.e., prolactin, insulin, and hydrocortisone) and the specialized ECM, basement membrane (BM). Our previous work...

Université de Fribourg

Beneficial effect of insulin-like growth factor-1 on hypoxemic renal dysfunction in the newborn rabbit

Prévot, Anne ; Julita, Monique ; Tung, David K. ; Mosig, Dolores

In: Pediatric Nephrology, 2009, vol. 24, no. 5, p. 973-981

Acute normocapnic hypoxemia can cause functional renal insufficiency by increasing renal vascular resistance (RVR), leading to renal hypoperfusion and decreased glomerular filtration rate (GFR). Insulin-like growth factor 1 (IGF-1) activity is low in fetuses and newborns and further decreases during hypoxia. IGF-1 administration to humans and adult animals induces pre- and postglomerular...

Université de Fribourg

SV40-induced expression of calretinin protects mesothelial cells from asbestos cytotoxicity and may be a key factor contributing to mesothelioma pathogenesis

Henzi, Thomas ; Blum, Walter-Vincent ; Pfefferli, Martine ; Kawecki, Tadeusz J. ; Salicio, Valérie ; Schwaller, Beat

In: American Journal of Pathology, 2009, vol. 174, p. 2324-2336

The calcium-binding protein calretinin has emerged as a useful marker for the identification of mesotheliomas of the epithelioid and mixed types, but its putative role in tumor development has not been addressed previously. Although exposure to asbestos fibers is considered the main cause of mesothelioma, undoubtedly, not all mesothelioma patients have a history of asbestos exposure. The question...

Université de Fribourg

Cellular toxicity of TiO₂-based nanofilaments

Magrez, Arnaud ; Horvth, Lenke ; Smajda, Rita ; Salicio, Valérie ; Pasquier, Nathalie ; Forró, László ; Schwaller, Beat

In: ACS Nano, 2009, vol. 3, no. 8, p. 2274–2280

At present, nanofilaments are not exclusively based on carbon atoms but can be produced from many inorganic materials in the form of nanotubes and nanowires. It is essential to systematically assess the acute toxicity of these newly synthesized materials since it cannot be predicted from the known toxicity of the same material in another form. Here, the cellular toxicity of TiO₂-based...

Université de Fribourg

The thalamocortical projection systems in Primate : an anatomical support for multisensory and sensorimotor interplay

Cappe, Céline ; Morel, Anne ; Barone, Pascal ; Rouiller, Eric M.

In: Cerebral Cortex, 2009, vol. 19, no. 9, p. 2025-2037

Multisensory and sensorimotor integrations are usually considered to occur in superior colliculus and cerebral cortex, but few studies proposed the thalamus as being involved in these integrative processes. We investigated whether the organization of the thalamocortical (TC) systems for different modalities partly overlap, representing an anatomical support for multisensory and sensorimotor...

Université de Fribourg

Color and shape interactions in the recognition of natural scenes by human and monkey observers

Liebe, Stefanie ; Fischer, Elvira ; Logothetis, Nikos K. ; Rainer, Gregor

In: Journal of Vision, 2009, vol. 9, no. 5, p. 14

Trichromatic color vision is a fundamental aspect of the visual system shared by humans and non-human primates. In human observers, color has been shown to facilitate object identification. However, little is known about the role that color plays in higher level vision of non-human primates. Here, we addressed this question and studied the interaction between luminance- and color-based structural...

Université de Fribourg

Adipose tissue plasticity during catch-up fat driven by thrifty metabolism: relevance for muscle-adipose glucose redistribution during catch-up growth

Summermatter, Serge ; Marcelino, Helena ; Arsenijevic, Denis ; Buchala, Antony J. ; Aprikian, Olivier ; Assimacopoulos-Jeannet, Françoise ; Seydoux, Josiane ; Montani, Jean-Pierre ; Solinas, Giovanni ; Dulloo, Abdul G.

In: Diabetes, 2009, vol. 58, no. 10, p. 2228-2237

OBJECTIVE: Catch-up growth, a risk factor for later type 2 diabetes, is characterized by hyperinsulinemia, accelerated body-fat recovery (catch-up fat), and enhanced glucose utilization in adipose tissue. Our objective was to characterize the determinants of enhanced glucose utilization in adipose tissue during catch-up fat. RESEARCH DESIGN AND METHODS: White adipose tissue morphometry, lipogenic...