Development of molecularly imprinted polymer films used for detection of profenofos based on a quartz crystal microbalance sensor.

A quartz crystal microbalance (QCM) sensor based on molecularly imprinted ultra-thin films was developed for detecting profenofos in real samples. Films prepared by physical entrapment (MIP-A) and in situ self-assembly (MIP-B) were compared. The results indicated that the best sensing signal was obtained through the in situ self-assembly method. The QCM sensor chip was pretreated with 11-mercaptoundecanoic acid (MUA) to form a self-assembled monolayer (SAM), and then polymer films were immobilized directly on the SAM using surface-initiated radical polymerization. In this paper, all detection experiments were taken in air. The reaction was processed in solution, and the electrode was washed with deionized water and dried with N(2) before QCM measurement. The film was characterized by a scanning electron microscope (SEM), AC impedance and cyclic voltammetry. Analysis of the QCM response in the presence of different concentrations of profenofos showed a good linear correlation during 1.0 × 10(-8) to 1.0 × 10(-5) mg mL(-1) (y = 5log x + 42.5, R = 0.9960) and 1.0 × 10(-5) to 1.0 × 10(-3) mg mL(-1) (y = 25.86log x + 146, R = 0.9959), respectively. The MIP-QCM sensor was used to detect profenofos in tap water, and showed good recovery and repeatability.

Forecasting the incidence of tuberculosis in China using the seasonal auto-regressive integrated moving average (SARIMA) model.

OBJECTIVES: The aims of this study were to develop a forecasting model for the incidence of tuberculosis (TB) and analyze the seasonality of infections in China; and to provide a useful tool for formulating intervention programs and allocating medical resources. METHODS: Data for the monthly incidence of TB from January 2004 to December 2015 were obtained from the National Scientific Data Sharing Platform for Population and Health (China). The Box-Jenkins method was applied to fit a seasonal auto-regressive integrated moving average (SARIMA) model to forecast the incidence of TB over the subsequent six months. RESULTS: During the study period of 144 months, 12,321,559 TB cases were reported in China, with an average monthly incidence of 6.4426 per 100,000 of the population. The monthly incidence of TB showed a clear 12-month cycle, and a seasonality with two peaks occurring in January and March and a trough in December. The best-fit model was SARIMA (1,0,0)(0,1,1)12, which demonstrated adequate information extraction (white noise test, p>0.05). Based on the analysis, the incidence of TB from January to June 2016 were 6.6335, 4.7208, 5.8193, 5.5474, 5.2202 and 4.9156 per 100,000 of the population, respectively. CONCLUSIONS: According to the seasonal pattern of TB incidence in China, the SARIMA model was proposed as a useful tool for monitoring epidemics.

Simultaneous and combined detection of multiple tumor biomarkers for prostate cancer in human serum by suspension array technology.

Tumor markers (TMs) play an important role in clinical rapid screening and diagnosis for prostate cancer (PCa). In this study, we describe a competitive method to establish the multiplex suspension array by tumor biomarkers coated on distinguishable microbeads which competing with free biomarkers for their complementary antibodies (Ab) in one single reaction system for simultaneous and combined detection of prostate TMs in human serum. The volumes of the targets coupled onto the beads and their complementary Abs were optimized. The suspension array standard curves correlated well with PCa biomarkers (R(2)>0.9968). PCa biomarker levels were quantified using median fluorescent intensities. The working ranges of prostate-specific antigen (PSA), prostate stem cell antigen (PSCA), prostate-specific membrane antigen (PSMA) and prostatic acid phosphatase (PAP) were 0.47-502.94, 1.00-923.35, 1.00-524.79, and 1.73-176.07ngmL(-1) in serum samples, respectively. This method was compared to indirect competitive enzyme linked immunosorbent assay. It was found that high concordance between the two technologies resulted from serum samples of the eight PCa patients. The multiplex suspension array technology is specific to PCa biomarkers, displayed no significant cross-reactivity, and remains stable for 6 months. We also characterized the bead surface microstructures under different conditions employing a field emission scanning electron microscope. The suspension array is a straightforward and reliable method for analysis of multiple TMs with simple operation, high sensitivity at a low cost.