Comparison of the antimicrobial photocatalytic activities of SiO2 and Au@SiO2 nanostructures in water decontamination.

Photocatalytic disinfection of Escherichia coli suspension by silicon dioxide nanoparticles and silicon dioxide/gold nanocomposite in a batch reactor is investigated experimentally and results are compared. Silica nanoparticles were synthesized by Stöber method and pulsed laser ablation method was employed to prepare gold nanoparticles in distilled water. Composition of two nanoparticles species was carried out, using the second harmonic pulse of Nd:YAG laser, whose wavelength is in the absorption spectra of gold nanoparticles. Results confirm a decrease in the bandgap energy of silica nanoparticles after composition. Escherichia coli were selected as an indicator of the microbial water contamination. Disk diffusion method was used to evaluate the antimicrobial potential of SiO2 and Au@SiO2 nanostructures. Photocatalytic activities of both nanostructures were examined in dark, and under the irradiation of UV and visible light. In all conditions, the performance of Au@SiO2 nanocomposites was higher than SiO2 nanoparticles. In dark condition the higher biocidal nature and activity of Au nanoparticles and for the case of UV radiation, decreasing the bandgap energy and recombination rate of SiO2 nanoparticles after composition with Au increased the efficiency. For the case of visible light radiation, surface plasmon resonances effects, and local heat of Au nanoparticles were responsible for increasing the efficiency. RESEARCH HIGHLIGHTS: Doping large bandgap semiconductors nanostructures, such as silica with metal nanoparticles, such as gold will improve their photocatalytic activity to work in visible light. In this mechanism, gold nanoparticles act as effective traps to prevent the recombination of photogenerated electron-hole pairs. Other mechanisms, such as Schottky barrier formation, surface plasmon resonance absorption of gold nanoparticles, and biocidal nature of the gold nanoparticles are effective in increasing the efficiency of Au doped silica nanostructures.

Erratum: Carrier Status for p.Gly61Glu and p.Arg368His CYP1B1 Mutations Causing Primary Congenital Glaucoma in Iran.

[This corrects the article DOI: 10.18502/jovr.v16i4.9747.].

Carrier Status for p.Gly61Glu and p.Arg368His CYP1B1 Mutations Causing Primary Congenital Glaucoma in Iran.

PURPOSE: To estimate carrier frequencies of CYP1B1 mutations p.Gly61Glu and p.Arg368His, respectively, in Talesh and the east of Guilan province in Iran with a maximum error of 2%. Previously, it was shown that these CYP1B1 mutations may be relatively prevalent in these regions. METHODS: Population-based screenings were performed. DNA was extracted from saliva samples of 1036 individuals from Talesh and 3029 individuals from the east of Guilan. P.Gly61Glu and p.Arg368His screenings were performed, respectively, by RFLP and ARMS-based PCR protocols. For confirmation, the DNA of individuals with mutations was sequenced using the Sanger protocol. RESULTS: Nine individuals from Talesh (0.86%; 95%CI: 0.45-1.64%) carried the p.Gly61Glu mutation, and 73 from the east of Guilan (2.41%; 95%CI: 1.91-3.04%) carried p.Arg368His. There was no significant difference in frequencies between urban and rural regions of the various cities, nor among four cities within the east of Guilan. CONCLUSION: The frequencies of p.Gly61Glu carriers in Talesh and of p.Arg368His carriers in the east of Guilan were within the 95% confidence interval of a previous study based on screenings of fewer individuals. The reliability of the recent estimates is higher, as the confidence interval for p.Gly61Glu decreased from 6.5% to 1.19% and the interval for p.Arg368His decreased from 4% to 1.13%. Based on the new findings, the maximum expected frequency of p.Gly61Glu carriers in Talesh is 1.64%, and of p.Arg368His carriers in the east of Guilan is 3%. The need for performing premarital screenings in the respective cities can be evaluated.

Factors affecting sedimentational separation of bacteria from blood.

Rapid diagnosis of blood infections requires fast and efficient separation of bacteria from blood. We have developed spinning hollow disks that separate bacteria from blood cells via the differences in sedimentation velocities of these particles. Factors affecting separation included the spinning speed and duration, and disk size. These factors were varied in dozens of experiments for which the volume of separated plasma, and the concentration of bacteria and red blood cells (RBCs) in separated plasma were measured. Data were correlated by a parameter of characteristic sedimentation length, which is the distance that an idealized RBC would travel during the entire spin. Results show that characteristic sedimentation length of 20 to 25 mm produces an optimal separation and collection of bacteria in plasma. This corresponds to spinning a 12-cm-diameter disk at 3,000 rpm for 13 s. Following the spin, a careful deceleration preserves the separation of cells from plasma and provides a bacterial recovery of about 61 ± 5%.

Rapid separation of very low concentrations of bacteria from blood.

A rapid and accurate diagnosis of the species and antibiotic resistance of bacteria in septic blood is vital to increase survival rates of patients with bloodstream infections, particularly those with carbapenem-resistant enterobacteriaceae (CRE) infections. The extremely low levels in blood (1 to 100CFU/ml) make rapid diagnosis difficult. In this study, very low concentrations of bacteria (6 to 200CFU/ml) were separated from 7ml of whole blood using rapid sedimentation in a spinning hollow disk that separated plasma from red and white cells, leaving most of the bacteria suspended in the plasma. Following less than a minute of spinning, the disk was slowed, the plasma was recovered, and the bacteria were isolated by vacuum filtration. The filters were grown on nutrient plates to determine the number of bacteria recovered from the blood. Experiments were done without red blood cell (RBC) lysis and with RBC lysis in the recovered plasma. While there was scatter in the data from blood with low bacterial concentrations, the mean average recovery was 69%. The gender of the blood donor made no statistical difference in bacterial recovery. These results show that this rapid technique recovers a significant amount of bacteria from blood containing clinically relevant low levels of bacteria, producing the bacteria in minutes. These bacteria could subsequently be identified by molecular techniques to quickly identify the infectious organism and its resistance profile, thus greatly reducing the time needed to correctly diagnose and treat a blood infection.

Rapid separation of bacteria from blood - Chemical aspects.

To rapidly diagnose infectious organisms causing blood sepsis, bacteria must be rapidly separated from blood, a very difficult process considering that concentrations of bacteria are many orders of magnitude lower than concentrations of blood cells. We have successfully separated bacteria from red and white blood cells using a sedimentation process in which the separation is driven by differences in density and size. Seven mL of whole human blood spiked with bacteria is placed in a 12-cm hollow disk and spun at 3000rpm for 1min. The red and white cells sediment more than 30-fold faster than bacteria, leaving much of the bacteria in the plasma. When the disk is slowly decelerated, the plasma flows to a collection site and the red and white cells are trapped in the disk. Analysis of the recovered plasma shows that about 36% of the bacteria is recovered in the plasma. The plasma is not perfectly clear of red blood cells, but about 94% have been removed. This paper describes the effects of various chemical aspects of this process, including the influence of anticoagulant chemistry on the separation efficiency and the use of wetting agents and platelet aggregators that may influence the bacterial recovery. In a clinical scenario, the recovered bacteria can be subsequently analyzed to determine their species and resistance to various antibiotics.

Weight self-stigma and its association with quality of life and psychological distress among overweight and obese women.

BACKGROUND: There are limiting studies evaluating the weight self-stigma and its association with eating disorders and health concerns. However, no study is available evaluating weight self-stigma and its determinants among reproductive age women in Iran. The aim of this study was to evaluate weight self-stigma and its association with quality of life and psychological distress among overweight and obese Iranian women. MATERIALS AND METHODS: The current cross-sectional study was performed among 170 women aged 17-45 years referring to health centers of Tabriz-Iran. Anthropometric assessments were performed. Weight self-stigma was assessed by weight self-stigma questionnaire (WSSQ). Evaluation of quality of life and psychological distress was performed using SF-12 and general health questionnaires (GHQ-12), respectively. Analysis of data was performed by multivariate hierarchical regression analysis using SPSS 18 software. RESULTS: In this study, the multivariate hierarchical regression analysis revealed that being married and having low total weight self-stigma and fear of enacted stigma (FES) scores were associated with better physical component summary scores (p < 0.05). Whereas, younger ages and lower total weight self-stigma scores were associated with better mental component summary scores. In addition, lower weight self-stigma total scores and lower self-devaluation scores were predictors of lower psychological distress. CONCLUSION: Our results indicated the negative impacts of weight self-stigma on quality of life and psychological distress among overweight and obese women. Since weight stigma might be a potent barrier of obese individuals to engage in health promoting behaviors, therefore, the results of the current study further warrants the need for developing interventional strategies to reduce the adverse impacts of weight stigma on quality of life via including the reduction of weight self-stigma as a key therapeutic goal in obesity treatment programs.

Rapid separation of bacteria from blood-review and outlook.

The high morbidity and mortality rate of bloodstream infections involving antibiotic-resistant bacteria necessitate a rapid identification of the infectious organism and its resistance profile. Traditional methods based on culturing the blood typically require at least 24 h, and genetic amplification by PCR in the presence of blood components has been problematic. The rapid separation of bacteria from blood would facilitate their genetic identification by PCR or other methods so that the proper antibiotic regimen can quickly be selected for the septic patient. Microfluidic systems that separate bacteria from whole blood have been developed, but these are designed to process only microliter quantities of whole blood or only highly diluted blood. However, symptoms of clinical blood infections can be manifest with bacterial burdens perhaps as low as 10 CFU/mL, and thus milliliter quantities of blood must be processed to collect enough bacteria for reliable genetic analysis. This review considers the advantages and shortcomings of various methods to separate bacteria from blood, with emphasis on techniques that can be done in less than 10 min on milliliter-quantities of whole blood. These techniques include filtration, screening, centrifugation, sedimentation, hydrodynamic focusing, chemical capture on surfaces or beads, field-flow fractionation, and dielectrophoresis. Techniques with the most promise include screening, sedimentation, and magnetic bead capture, as they allow large quantities of blood to be processed quickly. Some microfluidic techniques can be scaled up. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:823-839, 2016.