[Photocatalytic removal of escherichia coli and streptococcus faecalis from water using immobilized ZnO nanoparticles]

Among different water treatment methods, photocatalytic process is applied as a new efficient technology with appropriate potential to remove inorganic, organic and microbial contaminants from water. This study aimed to evaluate photocatalytic removal of Escherichia coli and Streptococcus faecalis bacteria as microbial indicators of drinking water using immobilized ZnO nanoparticles on glass plates. In this study, at first characteristics of ZnO nanoparticles were determined using scanning electron microscope [SEM] equipped with EDX system and X-ray diffraction [XRD], then ZnO nanoparticles were immobilized on glass plates using thermal method. The water samples containing the studied bacteria were irradiated by different intensities of UV-A and the effects of intensity and duration of irradiation, number of bacteria, number of immobilized ZnO nanoparticles layers, and reactor flow on the photocatalytic removal of the bacteria were evaluated. The optimal photocatalytic removal for both Escherichia coli and Streptococcus faecalis bacteria using one layer of immobilized ZnO nanoparticles, under 360 microWs/cm[2] UV-A radiation for 2-40 and 2-50 minutes was 10-1000 CFU/100 ml. Photocatalytic process efficiency was promoted by increasing the duration and intensity of radiation intensity up to 360microWs/cm[2] and was decreased by increasing the numbers of bacteria. In addition, Streptococcus faecalis bacteria were more resistant to photocatalytic process than Escherichia coli. photocatalytic removal of bacterial contaminations using immobilized ZnO nanoparticles on glass plates is a novel technology and effective process that could be considered for water disinfection

[Comparative study of three phakic intraocular lenses in correction of myopia]

To compare visual outcomes and surgical complications of three phakic intraocular lenses [pIOLs]; Artisan, Artiflex and the Implantable Collamer Lens [ICL] for correction of moderate to high myopia. In this historical cohort study, 112 myopic eyes that were operated between 2005 and 2010 and implanted with one of these three pIOLs were evaluated [Artisan 40 eyes, Artiflex 36 eyes and ICL 36 eyes]. Mean follow up period was 30 +/- 11 months. Intraoperative complications were evaluated. All patients were recalled and a complete ophthalmologic examination including refraction, best corrected visual acuity [BCVA] and intraocular pressure was performed. Pachymetry, endothelial cell count as well as postoprerative higher order aberrations were evaluated and compared with corresponding preoperative values. No significant intraoperative complications were reported. BCVA improvement, more than one line on the Snellen chart occurred in 25%, 19.4% and 38.9% of eyes in Artisan, Artiflex and ICL groups, respectively [P=0.158]. Preoperative spherical equivalent [SE] in Artisan, Artiflex and ICL groups was -11.6 +/- 3.7, -9.59 +/- 1.97 and -12.3 +/- 4.8 diopters, respectively. Reduction changes in SE was not statistically significant among the 3 groups [P=0.237]. Mean reduction of astigmatism was 0.31 +/- 0.72, 0.45 +/- 0.62 and 0.0 +/- 0.57 in Artisan, Artiflex and ICL groups, respectively [P=0.07]. Postoperatively, 60% of Artisan, 91.7% of Artiflex and 77.8% of ICL eyes were within one diopter of emmetropia, but the change was statistically significant between Artisan and Artiflex groups [P=0.017]. Percentage of endothelial cell loss was 10 +/- 9%, 9 +/- 6% and 9 +/- 10% in Artisan, Artiflex and ICL groups, respectively [P=0.694]. Pachymetry changes was minimal and the difference among groups was not statistically significant [P=0.754]. Higher order aberrations [P=0.039], vertical trefoil [P=0.032] and spherical aberration [P=0.001] were higher in Artisan than ICL. Total aberrations [P=0.028] and spherical aberration [P=0.001] was higher in Artisan than Artiflex. Visual outcomes such as BCVA improvement, reduction in SE and astigmatism were comparable among Artisan, Artiflex and ICL groups. There was no significant intra and postoperative complications in the 3 groups. Due to the increased higher order aberrations and problems in quality of vision in myopic eyes after implantation of Artisan lens, ICL and Artiflex may be better choices

Selection of wastewater treatment process based on the analytical hierarchy process and fuzzy analytical hierarchy process methods

This paper presents an application of the analytical hierarchy process and fuzzy analytical hierarchy process methods for selecting the best wastewater treatment process. The analytical hierarchy process is one of the best ways for deciding among the complex criteria structure in different levels, and the fuzzy analytical hierarchy process is a synthetic extension of the classical method when the fuzziness of the decision makers are considered. After reviewing aerobic treatment processes operated in Iran's industrial estates and determining the main criteria used for treatment process evaluation, they are arranged in a hierarchy structure. Selection of the best wastewater treatment process is a multi-criteria decision making problem. Conventional methods are inadequate for dealing with the imprecise or vague nature of linguistic assessment. To overcome this difficulty, the fuzzy analytical hierarchy process is proposed for dealing with the vagueness of decision makers' judgments. The alternatives consist of extended aeration, absorption bio-oxidation, integrated fixed-film activated sludge, sequencing batch reactor, aerated lagoon. Based on the general condition of industrial estate's wastewater treatment plants, technical/administrative, economic and environmental criteria and their sub-criteria are weighted and then criteria evaluated and priorities of alternatives have been done by analytical hierarchy process and fuzzy analytical hierarchy process methods by the use of triangular fuzzy numbers. Finally, selection of the best process and ranking of these five processes are carried out by these foregoing methods, and some sensitivity analyses are conducted to show the results' sensitiveness to the changes of the weights of the evaluation criteria