In this paper, a new method based on phase congruency is proposed to measure pitch lengths and surface braiding angles of two-dimensional biaxial braided composite preforms. Lab space transform and BM3D (block-matching and 3D filter) are used first to preprocess the original acquired images. A corner detection algorithm based on phase congruency is then proposed to detect the corners of the preprocessed images. Pitch lengths and surface braiding angles are finally measured based on the detected corner maps. Experimental results show that our method achieves the automatic measurement of pitch lengths and the surface braiding angles of biaxial braided composite preforms with high accuracy.
Ionic liquid (IL) pretreatment of lignocellulosic materials has provided a new technical tool to improve lignocellulosic ethanol production. To evaluate the influence of the residual IL in the fermentable sugars from enzymatic hydrolysis of IL pretreatment of lignocellulosic materials on the subsequent ethanol fermentation, the toxicity of the IL 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) to Saccharomyces cerevisiae AY93161 was investigated. Firstly, the morphological structure, budding and metabolic activity of Saccharomyces cerevisiae AY93161 at different [BMIM]Cl concentrations were observed under an optical microscope. The results show that its single cell morphology remained unchanged at all [BMIM]Cl concentrations, but its reproduction rate by budding and its metabolic activity decreased with the [BMIM]Cl concentration increasing. The half effective concentration (EC50) and the half inhibition concentration (IC50) of [BMIM]Cl to Saccharomyces cerevisiae AY93161 were then measured using solid and liquid suspension culture and their value were 0.53 and 0.39 g.L-1 respectively. Finally, the influence of [BMIM]Cl on ethanol production was investigated. The results indicate that the [BMIM]Cl inhibited the growth and ethanol production of Saccharomyces cerevisiae AY93161. This toxicity study provides useful basic data for further development in lignocellulosic ethanol production by using IL technology and it also enriches the IL toxicity data.
Objective To investigate the epidemiologic features of an outbreak of SARS that occurred in a single diabetes room of a general hospital in Beijing in late March 2003.
Methods Field investigation was carried out in the ward, the nursing log and the hospitalization medical record of correlative patients were consulted. SARS-CoV in serum specimen from SARS patient was detected by PCR.
Results The room where SARS outbreak occurred was on the 13th floor of the 16-story main ward building. There were 6 beds in the room, living with 6 female patients (aged 45-67) who were all hospitalized due to type 2 diabetes. On March 24, 2003, Patient 1 began to have a fever and cough, chest X-ray showed pneumonia. Five and six days later, Patient 2 and Patient 3 began to have a fever, respectively. Finally, all of these 3 patients died. Their beds were all at the same side of the room, and the other 3 patients at the opposite side were not infected. Serum SARS CoV-RNA of the Patient 3 was positive by nest-PCR. The daughter-in-law of Patient 1 who accompanied Patient 1 by the bedside several days, mainly near the window, upwind of Patient 1, was not infected. Medical staff, family members and visitors of the 6 patients were not infected.
Conclusions This outbreak was not transmitted by aerosol. The distance droplets travels could be up to 3.43 meters. Droplet spread has direction, and the droplets direction of propagation is closely related with the wind direction and speed. Those at the downwind position of SARS patients were susceptible to be infected. Medical staff wore face masks and good natural ventilation of this ward building may be important reasons for the prevention of infection.
Introduction: A real-time RT-PCR method for identification and quantification of porcine epidemic diarrhoea virus (PEDV) strains in China was developed.
Material and Methods: Based on the conserved sequence of the PEDV nucleocapsid (N) gene, a primer pair and probe were designed to establish a TaqMan-MGB real-time RT-PCR assay for quantitative detection of the virus. The sequence was cloned into the pMD18-T vector and a series of diluted recombinant plasmids were used to generate a standard curve with an R2 value of 0.999.
Results: The developed quantitative PCR assay detected viral titres as low as 0.1 TCID50 with high specificity and no cross-reaction with other porcine viruses (PoRV, TGEV, PRRSV, or CSFV). The intra-batch and inter-batch coefficients of variation were both less than 1%, which indicated good reproducibility. Thirty clinical diarrhoea samples obtained from pigs in Shanghai and Fujian were analysed using this quantitative PCR assay. Out of these samples, 93.3% were found to be PEDV positive.
Conclusion: This approach is suitable for clinical sample identification and pathogenesis studies.