RESUMO
The synthesis of polynorbornene by ring opening metathesis polymerization (ROMP), in the presence of 1st and 2nd generation Grubbs catalyst-functionalized multiwalled carbon nanotubes (MWCNT), has been studied. MWCNTs were obtained by catalytic chemical vapour deposition (CCVD) of ethylene. A full characterization of the 1st and 2nd generation Grubbs catalyst-functionalized nanotubes was performed by FTIR and TG-DTG-MS. The amount of catalyst grafted to the nanotube surface was estimated. The activity of the catalyst-functionalized nanotubes in ROMP of 2-norbornene was found to be similar to that of bare 1st and 2nd generation Grubbs catalysts. The characterization of polynorbornene-carbon nanotube composites shows that the nanotubes are well dispersed in the polymer matrix.
RESUMO
The numb chin syndrome (NCS) is characterized by facial numbness along the distribution of the mental branch of the trigeminal nerve. Most cases of this syndrome that are not dental in origin have been associated with malignant tumors or diffuse metastatic disease, particularly with underlying lymphoproliferative diseases and breast cancer. NCS can appear together with other signs of neoplastic dissemination or constitute the presenting symptom of the disease. The appearance of this mental nerve neuropathy should be considered as a significant symptom for clinicians, and investigations to detect a possible cancer should be mandatory. We report 12 patients with the NCS as the presenting and isolated symptom of a generalized malignancy.