RESUMO
SCPEEK@MOF proton exchange membranes, where SCPEEK is sulfinyl chloride polyether ether ketone and MOF is a metal-organic framework, were prepared by doping Fe-MIL-101-NH2 into polymers. The amino group in the MOF and the -SOCl2 group in thionyl chloride polyether ether ketone cross-link to form a covalent bond through the Hinsberg reaction, and the prepared composite membrane has stronger stability than other electrostatic interactions and simple physical doping composite membranes. The formation of covalent bonds improves the water absorption of the composite membrane, which makes it easy for water molecules to form hydrogen bonds. Moreover, SPEEK as a proton conductive polymer and the synergy of MOFs improve the proton conductivity of composite membranes. The composite membranes were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The swelling rate, water absorption, mechanical stability, ion exchange capacity, and proton conductivity of the pure sulfonated polyether ether ketone (SPEEK) membrane were compared with those of the mechanically doped SPEEK/MOF membrane and the composite membrane SCPEEK@MOF doped with different ratios of Fe-MIL-101-NH2, and all of the SCPEEK@MOF showed superior performance. When the Fe-MIL-101-NH2 loading rate of the composite membrane is 2%, the proton conductivity of the composite membrane can reach 0.202 S cm-1 at 363 K and a 98% relative humidity, which is much higher than that of the SPEEK/MOF membrane obtained by simple physical doping under the same conditions.
RESUMO
OBJECTIVE: To evaluate the effect of increasing cardiopulmonary bypass (CPB) flow volume in improving outcome of patients with carotid artery stenosis performed coronary artery bypass grafting (CABG) procedure. METHODS: Fifty-one patients data collected from January 2006 to March 2008 and divided into two groups (A and B) based on the degree of the carotid artery stenosis diagnosed by ultrasound. Group A included 15 cases with one or both carotid artery stenosis more than 50%, 14 male and 1 female, aged (68.5 +/- 7.7) years old, 14 with hypertension, 2 with diabetes, 6 with myocardial infarction, 3 with cerebral infarction. Group B included 36 cases with stenosis less than 50%, 34 male and 2 female, aged (62.4 +/- 10.2) years old, 28 with hypertension, 7 with diabetes, 20 with myocardial infarction. Increasing CPB flow volume in A group to compare cerebral blood flow (CBF) within procedure in both groups. RESULTS: CPB flow volume in group A was much higher than it in group B (P = 0.001). Mean arterial blood pressure in group A was (67.0 +/- 9.1) mm Hg (1 mm Hg = 0.133 kPa), higher than group B (59.0 +/- 7.1) mm Hg (P = 0.009). There was no significant difference of CBF within procedure and neuropsychologic performance in both group as result. CONCLUSION: For the patients presenting with carotid artery stenosis undergoing the procedure of CABG with CPB, increasing CPB flow volume could improve significantly diseased side cerebral blood flow and might reduce neurological complications.