منابع مشابه
Local Structure and Dynamics of Trans-polyisoprene oligomers
Monoand poly-disperse melts of oligomers (average length 10 monomers) of trans-1,4-polyisoprene are simulated in full atomistic detail. The force-field is developed by means of a mixture of ab initio quantum-chemistry and an automatic generation of empirical parameters. Comparisons to NMR and scattering experiments validate the model. The local reorientation dynamics shows that for C−H vectors ...
متن کاملDegradation of trans-polyisoprene after root filling with thermoplasticized techniques.
AIM To evaluate ex vivo degradation of gutta-percha following six thermoplastic obturation techniques. METHODOLOGY Ninety human-extracted mandibular premolars were selected and divided randomly into nine groups for filling. Group 1: thermomechanical compaction for 3 s with Konne gutta-percha points (Konne Ind. e Com. de Mat. Odontol., Belo Horizonte, MG, Brazil); Group 2: thermomechanical com...
متن کاملClinical relevance of trans 1,4-polyisoprene aging degradation on the longevity of root canal treatment.
This in vivo study investigated the time of degradation of root filling material (trans 1,4-polyisoprene) retrieved from endodontically treated teeth and correlated the occurrence of degradation with the longevity of endodontics. Thirty-six root-filled teeth with different filling times (2 to 30 years) and with and without periapical lesions were selected. All teeth presented clinical indicatio...
متن کاملOverexpression of an isopentenyl diphosphate isomerase gene to enhance trans-polyisoprene production in Eucommia ulmoides Oliver
BACKGROUND Natural rubber produced by plants, known as polyisoprene, is the most widely used isoprenoid polymer. Plant polyisoprenes can be classified into two types; cis-polyisoprene and trans-polyisoprene, depending on the type of polymerization of the isoprene unit. More than 2000 species of higher plants produce latex consisting of cis-polyisoprene. Hevea brasiliensis (rubber tree) produces...
متن کاملEfficient synthesis of trans-polyisoprene compounds using two thermostable enzymes in an organic-aqueous dual-liquid phase system.
The trans-polyisoprene compounds are synthesized by trans-isoprenyl diphosphate synthase (IDS) with consecutive condensation of isopentenyl diphosphate (IPP) to dimethylallyl diphosphate (DMAPP). The in vitro condensation by IDS does not proceed efficiently by hydrophobic interaction between IDS and the hydrocarbon of longer products. In the present study, the enzymatic synthesis of trans-polyi...
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ژورنال
عنوان ژورنال: NIPPON GOMU KYOKAISHI
سال: 1984
ISSN: 1884-0442,0029-022X
DOI: 10.2324/gomu.57.723