ABSTRACT:The influence of the molecular structure of homogeneous fluids comprised of liquid crystalline polysiloxanes (LCSs) diluted in polydimethylsiloxane (DMS), on the increase in their viscosity upon application of an electric field (electrorheological effect, or the ER effect) was investigated, particularly in relation to the degree of polysiloxane polymerization, the composition of their mesogenic side chains, and the composition of alkyl spacers inserted between these two components. A large ER effect was observed in LCSs having spacer length of 3 carbons (C3) and diluted with DMS, even though little such effect was observed with no DMS dilution. The ER effect generally increased with increasing DMS dilution and with increasing mesogenic group content, main chain length, and spacer length. At the same time, however, the miscibility of the DMS solvent with the LC polymer decreased, resulting in instability and difficulty in measuring the shear stress at temperatures up to 40ЊC or higher. When spacers containing an ether bond were employed, on the other hand, little or no polymersolvent phase separation occurred, and the ER effect was strong and stable down to temperatures of 30ЊC or lower. With all of the LCSs, the ER effect was observed at temperatures above their isotropic phase transition temperature as measured by DSC.
Currently, there are no detailed reports on the effects of vitamin E-bonded polysulfone (PS) membrane dialyzers on intradialytic hypotension (IDH) in diabetic hemodialysis (HD) patients. This study was designed to evaluate changes in intradialytic systolic blood pressure (SBP) using “VPS-HA” vitamin E-bonded super high-flux PS membrane dialyzers. The subjects were 62 diabetic HD patients whose intradialytic SBP fell by more than 20%. Group A comprised patients who required vasopressors to be able to continue treatment or who had to discontinue therapy due to their lowest intradialytic SBP being observed at 210 min (28 patients). Group B comprised patients who showed no symptoms and required no vasopressors but showed a gradual reduction in blood pressure, with the lowest intradialytic SBP seen at the end of dialysis (34 patients). The primary outcome was defined as the lowest intradialytic SBP after 3 months using VPS-HA. Secondary outcomes included changes in the following: lowest intradialytic diastolic blood pressure, pulse pressure, pulse rate, plasma nitric oxide and peroxynitrite, serum albumin, and hemoglobin A1c. Group A's lowest intradialytic SBP had significantly improved at 3 months (128.0 ± 25.1 mm Hg vs. 117.1 ± 29.2 mm Hg; P = 0.017). Group B's lowest intradialytic SBP had significantly improved at 1 month (134.4 ± 13.2 mm Hg vs. 121.5 ± 25.8 mm Hg; P = 0.047) and 3 months (139.1 ± 20.9 mm Hg vs. 121.5 ± 25.8 mm Hg; P = 0.011). We conclude that VPS-HA may improve IDH in diabetic HD patients.
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