Investigation of biofilm formation among methicillin-resistant Staphylococcus aureus isolated from children

Background: The aim of the present study was to investigate biofilm formation among Methicillin-resistant Staphylococcus aureus (MRSA) isolated from children referring to a pediatric hospital in Tehran. Methods: In total, 98 MRSA isolates were collected from children referring to a pediatric hospital during 2014 - 2015. All the isolates were confirmed to be MRSA using PCR amplification of the mecA gene. The antibiotic susceptibility patterns of the isolates were determined using the Kirby-Bauer disk-diffusion and E-test methods. In order to assess the ability of biofilm formation among the isolates, Congo red agar (CRA) and Microtiter Plate (Mtp) methods were used. Results: All the isolates were found to be susceptible to linezolid and vancomycin and, likewise, the majority was susceptible to minocycline and rifampicin. CRA and Mtp methods showed that 81.6 and 63.3 of the MRSA isolates, respectively, were biofilm producers. Conclusions: The early identification of S. aureus and detection of biofilm formation by the Mtp method are essential steps towards the prevention of the most serious nosocomial infections. © 2017, Archives of Pediatric Infectious Diseases

Investigation of biofilm formation among methicillin-resistant Staphylococcus aureus isolated from children

Background: The aim of the present study was to investigate biofilm formation among Methicillin-resistant Staphylococcus aureus (MRSA) isolated from children referring to a pediatric hospital in Tehran. Methods: In total, 98 MRSA isolates were collected from children referring to a pediatric hospital during 2014 - 2015. All the isolates were confirmed to be MRSA using PCR amplification of the mecA gene. The antibiotic susceptibility patterns of the isolates were determined using the Kirby-Bauer disk-diffusion and E-test methods. In order to assess the ability of biofilm formation among the isolates, Congo red agar (CRA) and Microtiter Plate (Mtp) methods were used. Results: All the isolates were found to be susceptible to linezolid and vancomycin and, likewise, the majority was susceptible to minocycline and rifampicin. CRA and Mtp methods showed that 81.6 and 63.3 of the MRSA isolates, respectively, were biofilm producers. Conclusions: The early identification of S. aureus and detection of biofilm formation by the Mtp method are essential steps towards the prevention of the most serious nosocomial infections. © 2017, Archives of Pediatric Infectious Diseases

CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

CMB-S4---the next-generation ground-based cosmic microwave background (CMB) experiment---is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the Universe, from the highest energies at the dawn of time through the growth of structure to the present day. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semi-analytic projection tool, targeted explicitly towards optimizing constraints on the tensor-to-scalar ratio, $r$, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2--3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments given a desired scientific goal. To form a closed-loop process, we couple this semi-analytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for $r > 0.003$ at greater than $5\sigma$, or, in the absence of a detection, of reaching an upper limit of $r < 0.001$ at $95\%$ CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note: text overlap with arXiv:1907.0447

The Future Landscape of High-Redshift Galaxy Cluster Science

Large scale structure and cosmolog

CMB-S4

We describe the stage 4 cosmic microwave background ground-based experiment CMB-S4

CMB-S4: Forecasting Constraints on Primordial Gravitational Waves

Abstract: CMB-S4—the next-generation ground-based cosmic microwave background (CMB) experiment—is set to significantly advance the sensitivity of CMB measurements and enhance our understanding of the origin and evolution of the universe. Among the science cases pursued with CMB-S4, the quest for detecting primordial gravitational waves is a central driver of the experimental design. This work details the development of a forecasting framework that includes a power-spectrum-based semianalytic projection tool, targeted explicitly toward optimizing constraints on the tensor-to-scalar ratio, r, in the presence of Galactic foregrounds and gravitational lensing of the CMB. This framework is unique in its direct use of information from the achieved performance of current Stage 2–3 CMB experiments to robustly forecast the science reach of upcoming CMB-polarization endeavors. The methodology allows for rapid iteration over experimental configurations and offers a flexible way to optimize the design of future experiments, given a desired scientific goal. To form a closed-loop process, we couple this semianalytic tool with map-based validation studies, which allow for the injection of additional complexity and verification of our forecasts with several independent analysis methods. We document multiple rounds of forecasts for CMB-S4 using this process and the resulting establishment of the current reference design of the primordial gravitational-wave component of the Stage-4 experiment, optimized to achieve our science goals of detecting primordial gravitational waves for r > 0.003 at greater than 5σ, or in the absence of a detection, of reaching an upper limit of r < 0.001 at 95% CL

Effect of filler type on 3-body abrasion of dental composite

Statement of Problem: The relatively poor wear resistance of dental composite in stress bearing posterior situations has restricted wider clinical application of this restorative material. Purpose: The aim of this study was to evaluate the three body abrasive wear of a dental composite based on a new filler (leucite: KAl Si2O6) and to compare it with the wear resistance of a composite based on commonly used Aluminium – Barium Silicate filler. Materials and Methods: This research was an interventional study done in Iran polymer institute. Five specimens were considered in each group. All ceramic IPS Empress® (Ivoclar- Vivadent) ingots based on leucite crystals were ball milled, passed through an 800 sieve and used as filler. Experimental composites were prepared by mixing the silane- treated fillers with monomers (BisGMA and TEGDMA). Camphorquinone and amine were used as photoinitiator system. Degree of conversion of the light-cured and post-cured composites was measured using FTIR spectroscopy. The prepared pastes were inserted into plexy-glass mold and light cured (700 mw/cm2, &amp;#61472;40 s). Then for maximum degree of conversion specimens were post- cured (120&amp;ordm;C, 5 hours). Three body abrasion wear testing was performed using a wear machine with 50 rpm rotational movement. In this machine, pumice (150 meshes) was used as the third body. Weight loss of specimens in each group was measured by balance after each 50 hours. After wear testing SEM examination was made specimens in each group. The data were analyzed and compared using ANOVA and Tukey HSD tests (P&lt;0.05). Tetric Ceram was tested as commercial composite. Results: There were significantly differences between three body abrasive wear of composites. The ranking from lowest to highest was as follows: leucite composite (19%) &lt; Tetric Ceram (22%) &lt; glass composite (28%). leucite composite showed the highest wear resistance value, propably due to the crystalliniy and hardness of filler. Conclusion: Introduction of this new filler as an alternative to glass filler, significantly increases the wear resistance of the resin composites. Further investigations on mechanical properties of new composites would be beneficial in the development of new dental materials

The Stages of Change in Smoking Cessation Among Smokers of Khorramabad

Introduction: Improper lifestyle is one of the factors affecting the incidence of chronic diseases. According to the World Health Organization statistics, smoking causes four million deaths annually. Studies show that in 1993, 28.6% men and 3.6% of women older than 15 years in the country were smokers. The most practical stage behavior change model is Transtheoretical model. Therefore, this study used this model. Methods: This cross-sectional study was done on 200 smokers or ex- smokers of Khorramabad who had high school diploma or higher educational levels. Cluster sampling was conducted in two stages. Data was collected by a questionnaire whose validity and reliability had been approved. Data was analyzed by using SPSS statistical software 11.5 and descriptive statistics. P level <0.05 was considered as significant. Results: Mean age was 42.5±7.85 years. Regarding stages of change, 39.5% were in pre-contemplation stage, 25.5% in contemplation stage, 12% in preparation stage, 5.5% in action stage and 17.5% were in maintenance stage. Variables that had a significant relationship with stages of change included years of smoking (p=0.001), complications of smoking (0.000), and age (p=0.04). There was no significant relationship between marital status, education, family and income, and stages of change. Conclusion: In this study, majority of the population under study were in the early stages. It is therefore necessary to provide educational programs and develop strategies for the same. Due to the significant relationship between age and years of smoking and exposure to advanced stages of change, people should be made aware of the problems of smoking earlier so that they can decide as soon as possible about smoking cessation

Preconcentration and Determination of Antimony in Drinking Water Bottled by Modified Nano-Alumina

Abstract Introduction: Antimony trioxide (Sb2O3) has been utilized as a catalyst in polyethylene terephtalate (PET) production, and the studies conducted on the bottled water has demonstrated that antimony can be leached from PET bottles into drinking water. Methods: In this study, a simple method was applied in order to determine the trace amount of antimony in bottled drinking water based on preconcentration /solid phase extraction. The nano alumina modified with Schiff base ligand was used in regard with Sb preconcentration. The experiments were performed in a continuous system and HCI was used as eluent of Sb ion. Several chemical and flow variables were optimized for a quantitative preconcentration and determination of Sb ion. The atomic absorption spectroscopy was used to determine Sb ion concentration. In order to study the keeping conditions on the leaching of Sb ion from PET plastic, drinking water bottles were kept in different conditions(room temperature, sunny light and -18˚C). Results: The calibration graph was linear in the range of 0.5 to 15.0 ppm Sb with detection limit of 0.055 ppm. The flow rate of sample was optimized in range of 1.0-9.0 mLmin-1 and Sb ion can be quantitatively eluted at 90 Vsample: Veluent retio. Conclusion: The study results revealed that the modified nano alumina is an effective sorbent in regard with absorbing Sb ion from water and HCI 1M can be used as an appropriate eluent. Maximum leaching of Sb ion is observed when the bottled drinking water was exposed to the sun light. Keywords: Antimony; Bottled drinking water; Modified alumina; Preconcentratio