ROMP Copolymers for Orthogonal Click Functionalizations

The ring-opening metathesis polymerization using ruthenium carbene initiators developed by Grubbs et al. is one of the most functional group tolerant living polymerization methods known. One of the most used postpolymerization functionalization methods used today is the copper-catalyzed 1,3-dipolar cycloaddition between alkynes and organic azides. Organic azides are, however, not tolerated by ruthenium carbene initiators, and nonprotected alkynes have been shown to slow down the propagation reaction or react with the propagating species leading to broad molecular weight distributions. Here we report the copolymer synthesis of three orthogonally functionalizable monomers: one carrying an activated pentafluorophenyl ester, one a maleimide unit, and a third one a trialkylsilyl-protected alkyne. From these monomers, statistical terpolymers as well as diblock copolymers were synthesized with different molecular weights and monomer compositions or block ratios, respectively. Excellent control over molecular weight and molecular weight distribution could be achieved using Grubbs’ first-generation ruthenium carbene initiator. Herein we present the synthesis and orthogonal triple postpolymerization functionalization of these copolymers

Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls-1

average. Box : 2× standard deviation.<p><b>Copyright information:</b></p><p>Taken from "Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls"</p><p>http://www.biomedcentral.com/1471-230X/8/29</p><p>BMC Gastroenterology 2008;8():29-29.</p><p>Published online 17 Jul 2008</p><p>PMCID:PMC2515315.</p><p></p

Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls-0

Antibodies: A-F: Anti-Wilson Protein Antibody followed by a red fluorescent secondary antibody. B+D+F: DNA couterstain with Hoechst DNA dye. F is the marked detail out of E. Arrows indicate the lumen of the sweat gland. The Wilson protein is abundantly expressed in the secretory and ductular epithelial cells of the sweat glands both in human and normal rat, but not in the LEC rat, which has no expression of the Wilson protein. Magnification: A-D: 100×, E:40×, F: 600×. Bar: A-D 12 μm; E 30 μm; F 2 μm.<p><b>Copyright information:</b></p><p>Taken from "Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls"</p><p>http://www.biomedcentral.com/1471-230X/8/29</p><p>BMC Gastroenterology 2008;8():29-29.</p><p>Published online 17 Jul 2008</p><p>PMCID:PMC2515315.</p><p></p

Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls-4

Antibodies: A-F: Anti-Wilson Protein Antibody followed by a red fluorescent secondary antibody. B+D+F: DNA couterstain with Hoechst DNA dye. F is the marked detail out of E. Arrows indicate the lumen of the sweat gland. The Wilson protein is abundantly expressed in the secretory and ductular epithelial cells of the sweat glands both in human and normal rat, but not in the LEC rat, which has no expression of the Wilson protein. Magnification: A-D: 100×, E:40×, F: 600×. Bar: A-D 12 μm; E 30 μm; F 2 μm.<p><b>Copyright information:</b></p><p>Taken from "Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls"</p><p>http://www.biomedcentral.com/1471-230X/8/29</p><p>BMC Gastroenterology 2008;8():29-29.</p><p>Published online 17 Jul 2008</p><p>PMCID:PMC2515315.</p><p></p

Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls-2

D compared to controls. Wilson patients without detectable sweat volume were not included into the analysed groups. Circle: median. Bar: average. Box : 2× standard deviation. 3B: Sweat volumes of treated Wilson patients and untreated Only 4 of the 6 Wilson patients without treatment produced detectable volumes of sweat. The average sweat production of the 6 patients is given as a bar. Untreated Wilson patients show a very low sweat production. Bar: average. Box : 2× standard deviation.<p><b>Copyright information:</b></p><p>Taken from "Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls"</p><p>http://www.biomedcentral.com/1471-230X/8/29</p><p>BMC Gastroenterology 2008;8():29-29.</p><p>Published online 17 Jul 2008</p><p>PMCID:PMC2515315.</p><p></p

Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls-3

Producing more than 20 μl sweat. Circle: median. Bar: average. Box : 2× standard deviation.<p><b>Copyright information:</b></p><p>Taken from "Wilson protein expression, copper excretion and sweat production in sweat glands of Wilson disease patients and controls"</p><p>http://www.biomedcentral.com/1471-230X/8/29</p><p>BMC Gastroenterology 2008;8():29-29.</p><p>Published online 17 Jul 2008</p><p>PMCID:PMC2515315.</p><p></p

La naissance des jeux olympiques et le sport dans l'antiquité

The ultrasound-induced cleavage of macromolecules has become a routine experiment in the emerging field of polymer mechanochemistry. To date, it has not been conclusively proven whether the molecular weight of a polymer or its contour length is the determining factor for chain scission upon ultrasonication. Here we report comparative experiments that confirm unequivocally that the contour length is the decisive parameter. We utilized postpolymerization modifications of specifically designed precursor polymers to create polymers with identical chain length but different molecular mass. To demonstrate the universality of the findings, two different polymer backbones were utilizedpoly­(styrene) and poly­(norbornene imide alkyne)whose molecular weights were altered by bromination and removal of pendant triisopropylsilyl protecting groups, respectively. Solutions of the respective polymer pairs were subjected to pulsed ultrasound at 20 kHz and 10.4 W/cm² in order to investigate the chain scission trends. The effects of cleavage and sonochemical treatments were monitored by size exclusion chromatography. In both series, experimental data and calculations show that the molecular weight reduction upon sonication is the same for polymers with the same contour length