Modification of regenerated cellulose ultrafiltration membranes with multi-walled carbon nanotubes for enhanced antifouling ability: Field test and mechanism study.

Although ultrafiltration (UF) has been extensively employed for drinking water purification, it is crucial to further develop novel membrane materials to improve the antifouling capacity and satisfy the practical usage. Multi-walled carbon nanotubes (MWCNTs) have characteristics that could potentially improve the membrane antifouling performance. Therefore, in this study, modified cellulose UF membranes were prepared using MWCNTs of various outer diameters ranging from 10 to 20 nm to 40-60 nm. The antifouling properties of the modified membrane and natural organic matter (NOM) removal mechanism were investigated while treating water from a local drinking water source river. Overall, the antifouling ability increased by more than one-fold when the nascent cellulose membrane was coated with MWCNTs (outer diameter of 40-60 nm) at a loading of 17.4 g/m2. The molecular weight distribution profiles of the NOM in the raw water and permeates suggest the superior performance of the modified membranes in removing two major NOM fractions with molecular weights ranging from approximately 5 k-30 k and 500 k-1000 k. Based on its hydrophobicity, the NOM of the raw water was fractionated into the strong hydrophobic (SHPO), the weak hydrophobic, the strong hydrophilic and the moderately hydrophilic (MHPI) fractions. The WHPO fraction caused the highest fouling compared with the other fractions under consistent experimental conditions. Meanwhile, the modified membranes showed a preference for removing the MHPI and SHPO fractions. These results imply that MWCNTs can be employed to improve the antifouling property of cellulose UF membranes and have the potential to selectively remove moderately hydrophilic contaminants from water.

Detection of aberrant p16 methylation in the serum of colorectal cancer patients.

PURPOSE: This study was designed to detect aberrant p16 promoter methylation in the serum of patients with colorectal cancer (CRC) and to explore the possibility of using this assay in early detection or as a prognostic marker of CRC patients. EXPERIMENTAL DESIGN: Methylation-specific PCR was used to detect p16 methylation in DNA extracted from 52 CRCs and matching serum samples and control serum samples from 34 patients with adenomatous polyps and 10 healthy individuals. The association of p16 hypermethylation in serum DNA of CRC patients with clinicopathological characteristics was then analyzed. RESULTS: P16 hypermethylation was found in 20 of 52 (38%) CRCs. Among the 20 cases with aberrant methylation in the tumor tissues, similar changes were also detected in the serum of 14 (70%) cases. No methylated p16 sequences were detected in the peripheral serum of the other 32 CRC cases without these changes in the tumor, in 34 patients with adenomatous polyps, or in 10 healthy control subjects. Clinicopathological analysis revealed that p16 methylation in serum was significantly associated with later Dukes' stage (P = 0.03). CONCLUSIONS: This assay offers a potential means for the serum-based detection and/or monitoring of CRC patients.