TY - JOUR A1 - Milanos, Sinem A1 - Elsharif, Shaimaa A. A1 - Janzen, Dieter A1 - Buettner, Andrea A1 - Villmann, Carmen T1 - Metabolic Products of Linalool and Modulation of GABA\(_{A}\) Receptors JF - Frontiers in Chemistry N2 - Terpenoids are major subcomponents in aroma substances which harbor sedative physiological potential. We have demonstrated that various monoterpenoids such as the acyclic linalool enhance GABAergic currents in an allosteric manner in vitro upon overexpression of inhibitory α1β2 GABA\(_{A}\) receptors in various expression systems. However, in plants or humans, i.e., following intake via inhalation or ingestion, linalool undergoes metabolic modifications including oxygenation and acetylation, which may affect the modulatory efficacy of the generated linalool derivatives. Here, we analyzed the modulatory potential of linalool derivatives at α1β2γ2 GABA\(_{A}\) receptors upon transient overexpression. Following receptor expression control, electrophysiological recordings in a whole cell configuration were used to determine the chloride influx upon co-application of GABA EC\(_{10-30}\) together with the modulatory substance. Our results show that only oxygenated linalool metabolites at carbon 8 positively affect GABAergic currents whereas derivatives hydroxylated or carboxylated at carbon 8 were rather ineffective. Acetylated linalool derivatives resulted in non-significant changes of GABAergic currents. We can conclude that metabolism of linalool reduces its positive allosteric potential at GABAA receptors compared to the significant potentiation effects of the parent molecule linalool itself. KW - Cys-loop receptor KW - GABA\(_{A}\) KW - receptor KW - linalool KW - linalyl acetate KW - oxygenation KW - patch-clamp Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170779 VL - 5 IS - 46 ER - TY - JOUR A1 - Born, Dennis-Peter A1 - Holmberg, Hans-Christer A1 - Goernet, Florian A1 - Sperlich, Billy T1 - A novel compression garment with adhesive silicone stripes improves repeated sprint performance – a multi-experimental approach on the underlying mechanisms JF - BMC Sports Science, Medicine and Rehabilitation N2 - Background Repeated sprint performance is determined by explosive production of power, as well as rapid recovery between successive sprints, and there is evidence that compression garments and sports taping can improve both of these factors. Methods In each of two sub-studies, female athletes performed two sets of 30 30-m sprints (one sprint per minute), one set wearing compression garment with adhesive silicone stripes (CGSS) intended to mimic taping and the other with normal clothing, in randomized order. Sub-study 1 (n = 12) focused on cardio-respiratory, metabolic, hemodynamic and perceptual responses, while neuronal and biomechanical parameters were examined in sub-study 2 (n = 12). Results In both sub-studies the CGSS improved repeated sprint performance during the final 10 sprints (best P < 0.01, d = 0.61). None of the cardio-respiratory or metabolic variables monitored were altered by wearing this garment (best P = 0.06, d = 0.71). Also during the final 10 sprints, rating of perceived exertion by the upper leg muscles was reduced (P = 0.01, d = 1.1), step length increased (P = 0.01, d = 0.91) and activation of the m. rectus femoris elevated (P = 0.01, d = 1.24), while the hip flexion angle was lowered throughout the protocol (best P < 0.01, d = 2.28) and step frequency (best P = 0.34, d = 0.2) remained unaltered. Conclusion Although the physiological parameters monitored were unchanged, the CGSS appears to improve performance during 30 30-m repeated sprints by reducing perceived exertion and altering running technique. KW - textile KW - tissue saturation index KW - venous system KW - video analysis KW - oxygen uptake KW - blood flow KW - clothing KW - oscillation KW - oxygenation Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-120591 SN - 2052-1847 VL - 6 IS - 21 ER - TY - JOUR A1 - Born, Dennis-Peter A1 - Holmberg, Hans-Christer A1 - Goernert, Florian A1 - Sperlich, Billy T1 - A novel compression garment with adhesive silicone stripes improves repeated sprint performance – a multi-experimental approach on the underlying mechanisms JF - BMC Sports Science, Medicine and Rehabilitation N2 - Background Repeated sprint performance is determined by explosive production of power, as well as rapid recovery between successive sprints, and there is evidence that compression garments and sports taping can improve both of these factors. Methods In each of two sub-studies, female athletes performed two sets of 30 30-m sprints (one sprint per minute), one set wearing compression garment with adhesive silicone stripes (CGSS) intended to mimic taping and the other with normal clothing, in randomized order. Sub-study 1 (n = 12) focused on cardio-respiratory, metabolic, hemodynamic and perceptual responses, while neuronal and biomechanical parameters were examined in sub-study 2 (n = 12). Results In both sub-studies the CGSS improved repeated sprint performance during the final 10 sprints (best P < 0.01, d = 0.61). None of the cardio-respiratory or metabolic variables monitored were altered by wearing this garment (best P = 0.06, d = 0.71). Also during the final 10 sprints, rating of perceived exertion by the upper leg muscles was reduced (P = 0.01, d = 1.1), step length increased (P = 0.01, d = 0.91) and activation of the m. rectus femoris elevated (P = 0.01, d = 1.24), while the hip flexion angle was lowered throughout the protocol (best P < 0.01, d = 2.28) and step frequency (best P = 0.34, d = 0.2) remained unaltered. Conclusion Although the physiological parameters monitored were unchanged, the CGSS appears to improve performance during 30 30-m repeated sprints by reducing perceived exertion and altering running technique. KW - tissue saturation index KW - blood flow KW - clothing KW - oscillation KW - oxygenation KW - oxygen uptake KW - textile KW - venous system KW - video analysis Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-116995 UR - http://www.biomedcentral.com/2052-1847/6/21 VL - 6 IS - 21 ER - TY - THES A1 - Hofmann, Marco T1 - Ferriomethyl- und Wolframiomethyl-substituierte Silane, Silanole und Siloxane T1 - Ferriomethyl- and Tungsteniomethyl-substituted silanes, silanols and siloxanes N2 - Das Interesse an Übergangsmetall-substituierten Siloxanen ist in den vergangenen Jahren stark angewachsen. Dies ist vor allem darauf zurückzuführen, dass diesen Systemen eine wichtige Modellfunktion für auf Silica-Oberflächen verankerte, katalytisch aktive Übergangsmetallkomplexe zukommt, die eine Vielzahl organischer Reaktionen katalysieren und dabei sowohl die Vorteile der Homogenkatalyse als auch der Heterogenkatalyse in einem einzigen System vereinen. Weiterhin kommt ihnen auch eine wichtige Bedeutung als Vorstufen zur Darstellung von Silicon-Polymeren und Keramiken zu, die definierte Metallzentren in ihrem Polymer-Grundgerüst enthalten und somit als neue Werkstoffe mit hoher mechanischer und thermischer Stabilität sowie ausgezeichneten leitenden Eigenschaften dienen können. Metallosiloxane mit einer direkten Metall-Silicium-Bindung können über die entsprechenden Metallo-silanole generiert werden, die seit Beginn der 90er Jahre eine intensivere Bearbeitung erfahren. In dieser Arbeit wurden die ersten Vertreter von Metallo-silanolen dargestellt und bezüglich ihrer Reaktivität untersucht, in denen das Metall- und Siliciumatom durch einen Alkylidenspacer getrennt ist. Es wurde zunächst eine Reihe von C5R5(OC)2FeCH2-substituierten Silanolen über die Et3N-assistierte Hydrolyse von Ferriomethyl-chlorsilanen bzw. Oxygenierung von Si-H-funktionellen Ferriomethyl-silanen mit Dimethyldioxiran dargestellt. Die Stabilisierung durch das Metallfragment in β-Stellung zur Silanoleinheit erweist sich ebenfalls hinreichend für die Darstellung von Ferriomethyl-silandiolen und –silantriolen, wie anhand der Darstellung von Cp(OC)2Fe-CH2-Si(R)(OH)2 (R = Me, OH) nachgewiesen werden konnte. Allerdings zeigen diese Vertreter im Vergleich zu ihren Analoga mit direkter Fe-Si-Bindung eine z.T. deutlich erhöhte Eigenkondensationsneigung. Die Röntgenstrukturanalysen der Ferriomethyl-diorganosilanole C5R5(OC)2Fe-CH2-Si(Me)(R’)OH belegen deren Aggregation zu Tetrameren bzw. unendlichen Ketten im Festkörper über starke intermolekulare OH...O-Wasserstoffbrückenbindungen. Durch Et3N-assistierte Kondensation mit Organochlorsilanen, wie z.B. Me2Si(H)Cl lassen sich kontrolliert Ferriomethyl-substiuierte Di-, Tri- und Tetrasiloxane generieren. Auch der Aufbau von mehrkernigen Heterosiloxangerüsten ist möglich, wie exemplarisch anhand der Synthese von Cp(OC)2Fe-CH2-SiMe2O-M(Cl)Cp2 (M = Ti, Zr) überprüft wurde. Weiterhin können auch Modifikationen am Metallfragment vorgenommen werden, wie der photochemisch induzierte CO/PR3-Austausch an Cp(OC)2-CH2-SiMe2OH beweist. Die synthetisierten Ferriomethyl-siloxane mit δ-ständiger Si-H-Funktion eignen sich für weitere Umsetzungen, wie z.B. der oxidativen Addition der Si-H-Funktion an ungesättigte Metallfragmente. So lassen sich das Tri- bzw. Tetrasiloxan Cp(OC)2Fe-CH2-Si(R)(OSiMe2H)2 (R = Me, OSiMe2H) durch UV-Bestrahlung unter CO-Eliminierung glatt in die Cyclo(ferra)siloxane Cp(OC)(H)Fe-SiMe2-OSi(Me)(R)-OSiMe2 überführen. Abschließend wurde überprüft, ob sich die Chemie der Ferriomethyl-silanole auch auf andere Übergangsmetallfragmente übertragen lässt. Hierbei konnten Wolframiomethyl-silanole mit dem Cp(OC)2(Me3P)WCH2-Fragment dargestellt werden, wobei sich, im Gegensatz zu den Eisenvertretern, die Darstellungsmethode der Oxygenierung von Si-H-funktionellen Vorläufern als vorteilhafter erweist. N2 - The interest in transition metal substituted siloxanes has rapidly grown in recent years. This is mainly due to their ability to serve as model systems for catalytically active transition metal complexes immobilized on a silica surface combining the advantages of homogeneous as well as those of heterogeneous catalysis in one system. In addition, these systems are also considered as precursors in the production of silicon polymers and ceramics with well-defined metal centres in the polymer backbone and can so be applied as new materials with good mechanical and thermal stability and excellent conducting properties. Metallo-siloxanes with a direct metal-silicon bond can be generated via the corresponding metallo-silanols which raised a greater attention in the last ten years. In this work the first examples of metallo-silanols have been synthesized and studied in which the metal and silicon atom are separated by an alkylidene spacer group. A number of C5R5(OC)2FeCH2-substituted silanols has been generated via Et3N-assisted hydrolysis of ferriomethyl-chlorosilanes and oxygenation of Si-H-functional ferriomethyl-silanes with dimethyldioxirane, respectively. The stabilizing effect of the metal fragment in β-position to the silanol unit is sufficient for the isolation of ferriomethyl-silanediols und –silanetriols as could be demonstrated in the synthesis of Cp(OC)2Fe-CH2-Si(R)(OH)2 (R = Me, OH). However, these compounds show an enhanced tendency to self-condensation compared to their analogues with a direct metal-silicon bond. The X-ray structure analyses of the ferriomethyl-diorganosilanols C5R5(OC)2Fe-CH2-Si(Me)(R’)OH show their aggregation to tetramers or infinite chains in the solid state, respectively, via strong intermolecular OH...O hydrogen bonds. Ferriomethyl-substiuted di-, tri- and tetrasiloxanes can be generated by controlled Et3N-assisted condensation with organochlorosilanes, e.g. Me2Si(H)Cl. Even binuclear heterosiloxanes can be synthesized as was proved by the synthesis of Cp(OC)2Fe-CH2-SiMe2O-M(Cl)Cp2 (M = Ti, Zr). In addition, there are also modifications at the metal fragment possible like the photochemically induced CO/PR3 substitution at Cp(OC)2-CH2-SiMe2OH. Ferriomethyl-siloxanes with a Si-H function in δ-position are suitable for further modifications, e.g. oxidative addition of the Si-H function to electronically unsaturated metal fragments. UV irradiation of the tri- and tetrasiloxanes Cp(OC)2Fe-CH2-Si(R)(OSiMe2H)2 (R = Me, OSiMe2H) leads to CO elimination producing the cyclo(ferra)siloxanes Cp(OC)(H)Fe-[SiMe2-OSi(Me)(R)-OSiMe2]. Finally it was examined if the chemistry of ferriomethyl-silanols can be transferred to compounds with other transition metal fragments. Tungsteniomethyl-silanols with a Cp(OC)2(Me3P)WCH2 fragment can be generated, whereas in contrast to the synthesis of ferriomethyl-silanols, the oxygenation method via Si-H functional precursors is more favourable. KW - Übergangsmetallkomplexe KW - Siliciumorganische Verbindungen KW - Chemische Synthese KW - Metallo-silanole KW - Metallo-siloxane KW - Hydrolyse KW - Oxygenierung KW - Kondensation KW - metallo-silanols KW - metallo-siloxanes KW - hydrolysis KW - oxygenation KW - condensation Y1 - 2001 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-1181579 ER -