Biomedical subjects
Publications and source records attributed to Xiaofang Hu.
Unmodified gold nanoparticles effectively differentiate unfolded and folded DNA, thus providing a novel approach to colorimetrically probe aptamer-based recognition processes.
Quantitative structure-activity relationship studies (QSAR) on HEPTs were performed by using a new approach--supervised stochastic resonance (SSR) in this paper. Errors in physicochemical properties have great effects on variable selection and the predictive capability of QSAR models but errors-in-variables were seldom discussed in QSAR. In this paper, based on the theory of stochastic resonance (SR), SSR was proposed and employed to the problem. In SSR, errors and abundant variables were regarded as noise and the relevant descriptors as signals. In the nonlinear systems involved in the SR, the signal and the noise interact harmonically and the signal was consequently enhanced. Therefore, the correlation between the relevant variables and a specified activity of a series molecule was improved by SSR. It is demonstrated that the obtained QSAR models for HEPT analogues by SSR were comparable to those by published methods in their stability and predictivity. SSR is an efficient and promising approach to QSAR studies.
Quantitative structure-property relationship (QSPR) models of soil sorption coefficients for 32 persistent organic pollutants were constructed using our recently introduced Lu index and novel distance-based atom-type DAI topological indices. Using multiple linear regression technique, a 6-variable model was obtained with the correlation coefficient of estimations (R) being 0.95, and the standard error of estimations (s) being 0.23, and the correlation coefficient (R(cv)) and the standard error (s(cv)) in the leave-4-out cross-validation procedure are 0.90 and 0.31, respectively. The results in this study indicate that soil sorption coefficients of POPs are dominated by molecular size while some DAI indices have smaller influence.
The high energy cost of an electrochemical method is the fatal drawback that hinders its large scale application in wastewater treatment. In traditional single-chamber electrolysis cell, only direct oxidation at an anode exists. Although a small amount of hydrogen peroxide is produced at the cathode by reduction, it is transferred to the anode and destroyed there without adding much benefit to organic decomposition. A two-chamber electrolytic cell, connected with an electrolyte bridge, was developed in this work. In this new reactor, direct oxidation at anode and indirect oxidation by hydrogen peroxide at cathode can occur simultaneously. Therefore "dual electrodes oxidation" in one electrochemical reactor was achieved successfully. Compared to a traditional one cell reactor, this reactor cuts the energy cost by 50%, and thus might lead to reconsideration of the electrochemical role in wastewater treatment. A Pt/C gas diffusion electrode (GDE) is fabricated and used as a cathode fed with oxygen-containing gases to produce hydrogen peroxide. When purified air diffuses through the active layer on the GDE, oxygen is reduced to hydrogen peroxide with a high yield to decompose organics. It has been found that the direct oxidation process at an anodic zone is slightly affected by factors such as pH variation, Fe(II) existence and aeration, while indirect oxidation at the cathodic zone is strongly affected. Dye used as a model pollutant was oxidized into small organic acids in both anode and cathode regions in this electrolytic reactor. GC-MS and IR spectrum were employed to analyze the intermediates formed during the degradation. Twenty intermediates have been detected, including 14 esters, 3 acids and 3 compounds with NO2 or N-OH groups. Thereafter, the degradation pathways of dye Acid Red B are proposed.