Ein PH‐funktionalisiertes Polyphosphazen: ein Makromolekül mit hochflexiblem Grundgerüst

Raab, M.; Schick, G. Alan; Fondermann, Rebecca; Dolg, Michael; Henze, Wolfram; Weynand, Ulrike; Gschwind, Ruth M.; Fischer, Karl; Schmidt, Manfred; Niecke, Edgar

doi:10.1002/ange.200504208

Cited by 9 publications

(4 citation statements)

References 26 publications

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“…Living polymerization is a powerful synthetic tool that enables the construction of well‐defined macromolecules possessing controlled architectures and tailor‐made properties 1. 2 Despite considerable recent activity in the synthesis of polymers composed of inorganic elements,3, 4 living polymerization methods remain primarily the domain of organic polymer chemistry 5. The prospect of accessing macromolecules of controlled architecture possessing the unique properties imparted by inorganic functionalities is particularly attractive 6.…”

Section: Methodsmentioning

confidence: 99%

Ambient‐Temperature Living Anionic Polymerization of Phosphaalkenes: Homopolymers and Block Copolymers with Controlled Chain Lengths

Noonan

Gates

2006

Angewandte Chemie

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Section: Methodsmentioning

confidence: 99%

Ambient‐Temperature Living Anionic Polymerization of Phosphaalkenes: Homopolymers and Block Copolymers with Controlled Chain Lengths

Noonan

Gates

2006

Angewandte Chemie

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“…2,6-Dioxa-14,18-diazatricyclo-[18⋅4⋅0⋅0 7,12 ]-tetracosa- 7,9,11,20,22,24(1)-hexaene 1, 2,6-dioxa-14, 19-diazatricyclo-[19⋅4⋅0⋅0 7,12 ]-pentacosa- 7,9,11,21,23,25(1)-hexaene 2 and 2,7-dioxa-15,19-diazatricyclo-[19⋅4⋅0⋅0 8,13 ]-pentacosa-8, 10, 12, 21, 23, 25(1)-hexaene 3 40,41 were prepared according to the cited procedures. Also compound 4 was obtained from the reaction of 1 with N 3 P 3 Cl 6 according to the reported method.…”

Section: Synthesis Of Compoundsmentioning

confidence: 99%

“…[6][7][8][9] The different substituents that are bonded to phosphorus atoms are very effective for the determination of the physical and chemical properties of new phosphazene derivatives and polyorganophosphazenes. [10][11][12] Hence, researchers have focused on the replacement reactions of halogen atoms of halophosphazenes by different nucleophiles, e.g.…”

Section: Introductionmentioning

confidence: 99%

Phosphorus-nitrogen compounds: Part 15. Synthesis, anisochronism and the relationship between crystallographic and spectral data of monotopic spiro-crypta phosphazenes

et al. 2008

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The reactions of hexachlorocyclotriphosphazatriene, N 3 P 3 Cl 6 , with N 2 O 2 -donor type coronands,, respectively. The reaction of 4 with excess pyrrolidine leads to the formation of geminal. The 31 P-NMR spectra of 5 and 6 indicate that these compounds have anisochronism. The structures of 5, 6 and 7 were investigated by X-ray crystallography. For 7, the sums of the bond angles around the N atoms were 348⋅6(2)° and 349⋅7(2)° indicating that the N atoms have pyramidal configurations and are stereogenic. The relationship between the chemical shift values δP (spiro) and the Δ(P-N) (electron density transfer parameters) of 4, 5, 6, 7 and the analogous compounds as well as the relationship between the Δ(δP) values and the above mentioned Δ(P-N) are presented respectively. In addition, the relationship between the endocyclic NPN bond angles of these compounds and the 31 P-NMR chemical shifts of the spiro-phosphorus atoms were investigated. The spectroscopic and structural investigations of the compounds were made by elemental analyses, MS, FTIR, one-dimensional 1 H-, 13 C-, 31 P-NMR, DEPT and two-dimensional COSY, HETCOR, HMBC, homo-and heteronuclear correlation techniques.

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“…Erstmals konnte ein PH‐funktionalisiertes Polyphosphazen (25) durch Umsetzung von P(NMe2)2Cl mit Ammoniak bei −78 bis 0 °C erhalten werden. Als Endgruppen trägt dieses Polymer höchstwahrscheinlich (Me2N)2P(H)=N‐ (X) sowie (Me2N)(NH=)PH‐Gruppen (Y) 37)…”

Section: Ketten Und Polymereunclassified

Differentiation rather than aging of muscle stem cells abolishes their telomerase activity

O’Connor

Carlson

Conboy

2009

Biotechnology Progress

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A general feature of stem cells is the ability to routinely proliferate in order to build, maintain, and repair organ systems. Accordingly, embryonic and germline, as well as some adult stem cells, produce the telomerase enzyme at various levels of expression. Our results show that, while muscle is a largely post-mitotic tissue, the muscle stem cells (satellite cells) that maintain this biological system throughout adult life do indeed display robust telomerase activity. Conversely, primary myoblasts (the immediate progeny of satellite cells) quickly and dramatically down-regulate telomerase activity. This work thus suggests that satellite cells, and early transient myoblasts, may be more promising therapeutic candidates for regenerative medicine than traditionally utilized myoblast cultures. Muscle atrophy accompanies human aging, and satellite cells endogenous to aged muscle can be triggered to regenerate old tissue by exogenous molecular cues. Therefore, we also examined whether these aged muscle stem cells would produce tissue that is “young” with respect to telomere maintenance. Interestingly, this work shows that the telomerase activity in muscle stem cells is largely retained into old age wintin inbred “long” telomere mice and in wild-derived short telomere mouse strains, and that age-specific telomere shortening is undetectable in the old differentiated muscle fibers of either strain. Summarily, this work establishes that young and old muscle stem cells, but not necessarily their progeny, myoblasts, are likely to produce tissue with normal telomere maintenance when used in molecular and regenerative medicine approaches for tissue repair.

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Ein PH‐funktionalisiertes Polyphosphazen: ein Makromolekül mit hochflexiblem Grundgerüst

Cited by 9 publications

References 26 publications

Ambient‐Temperature Living Anionic Polymerization of Phosphaalkenes: Homopolymers and Block Copolymers with Controlled Chain Lengths

Ambient‐Temperature Living Anionic Polymerization of Phosphaalkenes: Homopolymers and Block Copolymers with Controlled Chain Lengths

Phosphorus-nitrogen compounds: Part 15. Synthesis, anisochronism and the relationship between crystallographic and spectral data of monotopic spiro-crypta phosphazenes

Differentiation rather than aging of muscle stem cells abolishes their telomerase activity

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