Electroosmotic Flow of Viscoelastic Fluid in a Nanoslit.

The electroosmotic flow (EOF) of viscoelastic fluid in a long nanoslit is numerically studied to investigate the rheological property effect of Linear Phan-Thien-Tanner (LPTT) fluid on the fully developed EOF. The non-linear Poisson-Nernst-Planck equations governing the electric potential and the ionic concentration distribution within the channel are adopted to take into account the effect of the electrical double layer (EDL), including the EDL overlap. When the EDL is not overlapped, the velocity profiles for both Newtonian and viscoelastic fluids are plug-like and increase sharply near the charged wall. The velocity profile resembles that of pressure-driven flow when the EDL is overlapped. Regardless of the EDL thickness, apparent increase of velocity is obtained for viscoelastic fluid of larger Weissenberg number compared to the Newtonian fluid, indicating the shear thinning behavior of the LPTT fluid. The effect of the Weissenberg number on the velocity distribution is less significant as the degree of EDL overlapping increases, due to the overall decrease of the shear rate. The increase (decrease) of polymer extensibility (viscosity ratio) also enhances the EOF of viscoelastic fluid.

The HECT E3 ubiquitin ligase NEDD4 interacts with and ubiquitylates SQSTM1 for inclusion body autophagy.

Our previous studies have shown that the HECT E3 ubiquitin ligase NEDD4 interacts with LC3 and is required for starvation and rapamycin-induced activation of autophagy. Here, we report that NEDD4 directly binds to SQSTM1 via its HECT domain and polyubiquitylates SQSTM1. This ubiquitylation is through K63 conjugation and is not involved in proteasomal degradation. Mutational analysis indicates that NEDD4 interacts with and ubiquitylates the PB1 domain of SQSTM1. Depletion of NEDD4 or overexpression of the ligase-defective mutant of NEDD4 induced accumulation of aberrant enlarged SQSTM1-positive inclusion bodies that are co-localized with the endoplasmic reticulum (ER) marker CANX, suggesting that the ubiquitylation functions in the SQSTM1-mediated biogenic process in inclusion body autophagosomes. Taken together, our studies show that NEDD4 is an autophagic E3 ubiquitin ligase that ubiquitylates SQSTM1, facilitating SQSTM1-mediated inclusion body autophagy.

[Study of the methods of wavelet feature extraction and neural network classification of fluorescence spectra to improve the diagnostic rate of colonic earlier stage cancer].

In order to improve the diagnostic rate of earlier stage colonic cancer with laser-induced 5-ALA-Pp IX fluorescence spectra, a novel method of extraction of fluorescence spectral feature using wavelet analysis and classification using artificial neural network trained with resilient back-propagation algorithm (R-BPNN) was developed. 504 spectra were collected from 8 normal SD rats, and 20 1,2-DMH-induced SD colon cancer models and 12 second generation rats of induced rats. 150 min later trail intravenous injections of 5-ALA dose of 25 mg x kg(-1) body weight (BW), and fluorescence spectra excited with 370 nm Ti-laser were collected in vivo. After preprocessing, 12 feature variants were extracted with wavelet analysis. With R-BPNN, all spectra were classified into two categories: normal or abnormal, which included dysplasia, early carcinoma (EC) and advanced carcinoma (AC). The sensitivity and specificity were 98.91% and 97.2% respectively. The accuracy of discriminating dysplasia, early carcinoma, and advanced carcinoma from normal tissue were 91.3%, 98.9% and 98.8 respectively. The result indicated that this method could effectively and easily diagnoses earlier stage colonic carcinomas.