;\ rap id m ethod for t he estimation of natural r ubber in vulcani zates of GR-S a nd nat ura l rubber by m eans of infra red spectrosco py is reported . Sampl es were carefully prepared to co ntal!1 known amou nts of .natural and GR-S rubber; the samples \I'ere v ulcan ized, extracted wL t h acetone, and dn ed III a vac u um oven. Specim ens from eac h sam ple were pyr olyzed in a combu st ion furn ace at 550 0 C. and the liquid pyrolyzates were a nalyzed by mfra red absorptLOn spectroscop y . An e mpLL"lcal relationship was de veloped in which thc band in te nsit ies at 11.02 a nd 11.25 mi crons were r elated to natural rubber content . Th e exp erimental error of .the m ethod is characterized by a stand ard deviation of a s ingle d etermln atLO n of 0 .023, \I'hlCh represe nts a pprox imately 3-percent nat ural rubber.
This r eport describes th e sy nt hesis of a new bis-bifunctional derivative of 8-hyd ro xyquinolin e, its reaction with a number of divalent, first-row trans it ion m etals to form coo rdin ation polymers, and a t hermogravimetric study of the thermal stabili ty of the polyme rs. The ligand, 5,5'-[methylenebis (p-phenylenen it rilometh ylid yne) ]di-8-quinolinol was prepared in a condensation r eaction between 5-formyl-8-hyd rox yq uin oline a nd 4,4'-meth yle nedianiline and subsequently treated with t he acetate salts of Mn(II) , Co(I1), N i(II), eu(II), and Zn (II). Th e metal coo rdi nated in t he backbone of t he polymer is sh own to be an important factor in gove rning the thermal stability w hen t he sampl es a re heated in vacuum.
A condensation reaction between 5amino-%hydroxyquinoline and terephthalaldehyde yielded a bis-bifunotional Schiff base ligand, 5,5'-[pphenylene-bis(methy1i-dynenitrilo)] di-%quinoliioi, which was used to produce coordination polymers containing Mn(II), Co(II), NYII), Cu(II), or Zn(I1) in the form of insoluble powders. The thermal stabilities of these polymers were evaluated in vacuum over the temperature range of 25-700°C. by using a newly constructed thermobalance having improved sensitivity. The results relate the decomposition of the polymers to the metal in the backbone aa well 88 to the organic ligand to which the metal is coordinated. Some discussion is devoted to the possible modes of decomposition of these polymers.
Between 1955 and 1987, 15 patients with hemangiopericytomas were seen at the University of Iowa Hospitals and Clinics. Twelve of these were thought to have localized tumors and three had metastatic disease at diagnosis. Seven of the 12 patients with localized disease were treated with surgery alone, four were treated with surgery and postoperative radiation therapy, and one was treated with surgery and chemotherapy. Only one of the seven patients initially treated with surgery alone has remained continuously free of disease, although two others were salvaged with radiation therapy. In contrast, all four patients initially treated with surgery and postoperative radiation therapy have remained alive with no evidence of disease in spite of the fact that three of these patients had gross residual tumor at the time of irradiation. Ten patients received radiation therapy at some stage of their management. Local tumor control was achieved at all sites receiving greater than 5500 cGy. Six patients received chemotherapy sometime during the course of their management, although no complete or partial responses were observed. In this small series, mitotic activity was not an accurate predictor of biologic behavior.
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