The Comparison of Toluene Removal Rate in Two Photocatalytic Oxidation Systems of ZnO and TiO2 Nanoparticles on SiO2 bed

Volatile organic compounds (VOCs) are one of the main group of air pollutants. Photocatalytic oxidation is one of the destructive methods for gaseous pollutants and has been received more attention in the past years. In this study investigated the comparison of the toluene removal efficiency by Photocatalytic Oxidation of Toluene by ZnO/SiO2 and TiO2/SiO2. In this study, the effect of parameters such as the amount of relative humidity, initial concentration of pollutant, the apparent speed of gas and the minimum speed of fluidizing of bed on the process of photocatalytic oxidation of Toluene is examined by comparison between TiO2/SiO2 and ZnO/SiO2 catalysts in a fluidized bed reactor. as it was explained, by absorption of water molecules on the surface of the catalyst and converting them to hydroxyl active radicals, these radicals act as a pushing factor in the reaction. The study also showed that an increase in the relative humidity in the 15–45% range would increase the efficacy of toluene oxidation. Conversion percentages between TiO2/SiO2 and ZnO/SiO2 catalysts were not significantly different (pv>0.05), while the reaction rate of ZnO/SiO2 catalyst was higher than TiO2/ SiO2 catalyst (p

The Effect of Subgingival Antimicrobial Therapy on the Levels of Stromelysin and Tissue Inhibitor of Metalloproteinases in Gingival Crevicular Fluid

Recent investigations imply that a key mechanism in the pathogenesis of periodontal disease may be the ability of oral micro-organisms to induce production and /or activation of matrix metalloproteinases in the host tissues. Stromelysin (SL) is a member of the matrix metalloproteinase family which may play a role in chronic inflammatory periodontitis. Extracellular control of these enzymes is performed by tissue inhibitor of metalloproteinases (TIMP) and during normal tissue turnover, inflammation and healing, levels of MMPs and TIMP will change. The effect of treatment on the levels of MMPs and inhibitors has been to decrease collagenase activity, to decrease the amount of collagenase and stromelysin (SL) produced, and to increase the level of TIMP. It has been suggested that the pharmacologic inhibition of MMP activity could play an important role in achieving a desirable outcome in periodontal therapy. In addition to antimicrobial effects, tetracyclines have been shown to be able to inhibit metalloproteinases (MMPs). However, recent results indicate that the inhibition of MMPs by systemic tetracycline depends on the drug concentration and type as well as the origin of the MMP. Therefore, theoretically a greater inhibitory effect on MMPs would be expected if higher concentrations of drug could be delivered to the site of action. Recently, there has been increasing interest in the use of locally delivered antibiotics in order to obtain a high concentration of the drug at the target site and to minimise potential systemic adverse effects. We therefore sought to investigate the efficacy of locally delivered antibiotics on the level of gingival crevicular fluid (GCF) stromelysin (SL) and tissue inhibitor of metalloproteinases (TIMP) on sites with a history of a poor response to mechanical treatment. 52 patients with 4 periodontal pockets >5 mm and bleeding on probing were randomised into four groups of 13 patients. One group received scaling and root planing alone and the other three groups received scaling and root planing plus a locally delivered antimicrobial system. These included 25% tetracycline fibre, 2% minocycline gel, and 25% metronidazole gel. The GCF samples taken at baseline and 6 weeks after treatments were analysed using an enzyme linked immunosorbent assay (ELISA). All treatments resulted in significant improvement in clinical parameters. The pocket depth reduction was significantly greater in the scaling plus tetracycline fibre group than the scaling alone group (p=0.003) . GCF SL levels significantly decreased after adjunctive tetracycline fibre (paired t-test, p=0.020) and minocycline gel (paired t-test, p=0.023) treatments whereas it remained almost unchanged in the other two groups. While the GCF TIMP level did not change significantly in the scaling and root planing alone XX group, it significantly increased for all three adjunctive antimicrobial treatments (for tetracycline fibre p<0.001, minocycline gel p=0.005, metronidazole gel p<0.001). The analysis of covariance (ANCOVA) on the baseline SL was used to reduce the error resulting from the variation in the baseline. The level of SL at baseline had a significant effect on the SL change following treatment (p<0.001), and this effect was positive i.e. the higher the baseline SL, the higher the reduction of SL. Treatment also had a significant effect on the reduction of SL (p=0.001). Follow-up analysis showed significant differences between; i) tetracycline fibre plus scaling and scaling alone groups (p=0.004); and ii) minocycline gel plus scaling and scaling alone groups Cp=0.002). There was a significant difference in TIMP levels between treatment groups (p=0.007). Furthermore, the analysis of TIMP levels revealed that a significant difference existed between the minocycline gel plus scaling and the scaling alone group (p=0.018), and also between the metronidazole gel plus scaling and the scaling alone group (p=0.001). Our observation that the mean level of SL decreased after antibiotic treatment could be explained by the fact that local delivery of antibiotics plus scaling and root planing may change the microbial flora. This may cause a larger decrease of SL than scaling and root planing alone. However, the greatest decrease was observed in the sites treated by tetracycline or minocycline delivery systems. Previous studies have also shown that tetracyclines, in addition to decreasing the level of periodontal bacteria, resulting in decrease of MMP activity in the gingiva, could decrease the synthesis of pro-MMPs and also protect the endogenous MMP inhibitors (TIMP-1) and other proteinase inhibitors (alpha1-antitrypsin) from degradation and inactivation by direct and indirect mechanisms. However, it cannot be established from this study whether the effect of the tetracyclines on the level of SL is direct, or indirect through the reduction in microbial challenge which could reduce the microbial proteases and inflammatory mediators such as cytokines, both of which could reduce the levels of human MMP. After treatment the level of free TIMP increased. This might be due to a reduction in MMPs which would bind to free TIMP

Investigating the Effect of UV Radiation Changes and Bed Temperature in Photocatalytic Destruction of Toluene in a Circular Fluid Bed Reactor

Increase the system efficiency in photocatalytic systems is necessary for economic aspects. In this study, for photocatalytic destruction of toluene in a circular fluid bed or substrate reactor, the effect of UV radiation changes and bed temperature was investigated. The Efficiency of the photocatalytic system was studied in various conditions of relative humidity variables, UV intensity and bed temperature. This study showed by increasing the photocatalyst loading percentage of more than 20%wt., there is no significant change in the efficiency of toluene degradation. In a steady state of all other parameters, when the intensity of the UV radiation rises from 5 w/m2 to 17 w/m2, Toluene degradation efficiency also has an increasing trend. Also, we found that with increasing temperature, the efficiency of photocatalytic oxidation of toluene is increasing. The independent effect of each of the variables on the efficiency of toluene removal are interdependent and mutually influential, and in order to have the appropriate efficiency, all variables should be examined together in the appropriate conditions

Virulence-Associated Gene Profiles of Avian Pathogenic Escherichia coli Isolated From Broilers With Colibacillosis: A Pilot Study in Iran

Background: Avian pathogenic Escherichia coli (APEC) causes economic losses in the chicken industry worldwide.Objective: In this study, virulence-associated gene profiles of APEC isolates were investigated by polymerase chain reaction (PCR).Materials and Methods: A total of 60 Escherichia coli isolates were collected from 60 colibacillosis cases from 30 broiler poultry farms in Alborz, Tehran, and Golestan provinces, Iran. After identification by biochemical tests, DNA was extracted by boiling method and 5 virulence-associated genes including: iutA, hlyF, iroN, ompT, and iss were detected by 2 multiplex PCR protocols.Results: Of the 60 APEC isolates, 26 (43.3%) isolates had at least three virulence genes from which 12 (20%) isolates were positive for all 5 virulence genes, whereas 34 (56.6%) carried no investigated virulence genes. Presence of iutA, hlyF, iroN, ompT, and iss genes in the APEC isolates were 17 (28.3%), 17 (28.3%), 24 (40%), 26 (43.3%), and 23 (38.3%), respectively.Conclusion: According to the results, four different virulence-associated gene profiles were seen in isolates, from which profile 1 with 12 (20%) isolates was predominant. These findings were in agreement with the previous reports

Fire Pathology in a Military Hospital Using the FRAME Technique

Background and Aim: Hospitals are One of the vital and sensitive places as well as practical that maintaining their function in normal conditions and in times of crisis is one of the biggest concerns of health system managers. By using the principles of fire safety, hospitals' vulnerability can be reduced. Fire is one of the risks that can lead to many human and financial losses as well as disruption of hospital performance. Fire risk assessment is a more effective way to assess the vulnerability, capacity and capability of the hospital. The aim of this study was to evaluate the risk of fire in one of the hospitals in Tehran to analyze the vulnerability of these uses. Methods: This cross-sectional study was performed by using the Fire Risk Assessment Method for Engineers (FRAME) in the hospital building of a military hospital. Fire risk was calculated using the formulas of the mentioned method in EXCEL software. Factors influencing the level of risk obtained were identified and evaluated. Results: The level of fire risk for residents in all units was higher than one. Level factor, fire load factor and normal protection factor were identified as effective factors that result in the existing fire risk level. Conclusion: The numerical value of the risk for the residents was at an unfavorable level. The results of this study showed that the use of FRAME method in assessing the risk of health facilities such as hospitals, by determining the strengths and weaknesses of the assessed locations, the possibility of identifying effective factors to predict and prevent accidents and maintain the performance of these centers at times. Be sensitive to such manmade or natural emergencie

A Comparative Evaluation of TiO 2

The most important parameters affecting the efficiency of catalysts for the oxidation of the surrounding materials are considered to be the thickness and uniformity of the catalyst layer. The present method for the determination of thickness used in most studies is the analysis of cross-sectional pictures from SEM imaging. This method, however, has several restrictions. This study proposes a feasible and simple method for evaluating the optimal thickness and uniformity using UVA light transmitted through the samples. Three techniques for catalyst deposition have been investigated in this study using UVA light transmitted through the samples and by measuring the photocatalytic activity. These methods include lowering, dip coating, and spraying, which showed coefficients of variation for the coated catalyst weight of 28.4%, 13.6%, and 3.24%, respectively. The samples from the lowering, dip coating, and spraying techniques showed UVA transmissions of 95.02%, 68.8%, and 15.6%, respectively. The spraying technique displayed the lowest values for both. The estimated removal efficiencies (%RE/mgcm−2) for lowering, dip coating, and spraying were 18.42, 16.84, and 24.15, respectively. Using these analyses it was determined that the spraying technique yielded the best photocatalytic oxidation performance of the three techniques studied

Total Fume and Metal Concentrations during Welding in Selected Factories in Jeddah, Saudi Arabia

Welding is a major industrial process used for joining metals. Occupational exposure to welding fumes is a serious occupational health problem all over the world. The degree of risk to welder’s health from fumes depends on composition, concentration, and the length of exposure. The aim of this study was to investigate workers’ welding fume exposure levels in some industries in Jeddah, Saudi Arabia. In each factory, the air in the breathing zone within 0.5 m from welders was sampled during 8-hour shifts. Total particulates, manganese, copper, and molybdenum concentrations of welding fumes were determined. Mean values of eight-hour average particulate concentrations measured during welding at the welders breathing zone were 6.3 mg/m3 (Factory 1), 5.3 mg/m3 (Factory 2), 11.3 mg/m3 (Factory 3), 6.8 mg/m3 (Factory 4), 4.7 mg/m3 (Factory 5), and 3.0 mg/m3 (Factory 6). Mean values of airborne manganese, copper, and molybdenum levels measured during welding were in the range of 0.010 mg/m3–0.477 mg/m3, 0.001 mg/m3–0.080 mg/m3 and 0.001 mg/m3–0.058 mg/m3 respectively. Mean values of calculated equivalent exposure values were: 1.50 (Factory 1), 1.56 (Factory 2), 5.14 (Factory 3), 2.21 (Factory 4), 2.89 (Factory 5), and 1.20 (Factory 6). The welders in factories 1, 2, 3, and 4 were exposed to welding fume concentration above the SASO limit value, which may increase the risk of respiratory health problems

Percutaneous transluminal mitral commissurotomy in pregnant women with severe mitral stenosis

Background: Mitral stenosis tends to worsen during pregnancy because of the increase in the cardiac output and the heart rate. In nonresponders to medical therapy, percutaneous transluminal mitral commissurotomy (PTMC) may be performed when there is a suitable valvular anatomy. In this study, we aimed to investigate the clinical and fetal outcomes of pregnant women with mitral stenosis who underwent PTMC. Methods: Thirty-one patients undergoing PTMC during pregnancy were enrolled in this study. The mitral valve area (MVA), the transmitral valve mean gradient (MVMG), and the severity of mitral regurgitation were assessed pre- and postprocedurally by transthoracic and transesophageal echocardiography. The radiation time was measured during the procedure. The patients were followed up during pregnancy, and the neonates were monitored for weight, height, the head circumference, the birth Apgar score, and the adverse effects of radiation for at least 12 months. Results: PTMC was successfully performed on 29 (93.5) patients. No maternal death or pulmonary edema was reported. The mean MVA significantly increased (from 0.73±0.17 cm2to 1.28±0.24 cm2; P&lt;0.001), and the mean MVMG significantly decreased (from 19.62±5.91 mmHg to 8.90±4.73 mmHg; P&lt;0.001) after the procedure. A significant decrease in the systolic pulmonary artery pressure was also detected. Mitral regurgitation did not increase in severity in 16 (51.6) patients. There was no significant relationship between the Apgar score, weight, height, and the head circumference at birth and at the radiation time. Conclusion: In our series, PTMC during pregnancy was a safe and effective procedure. Lowering the radiation time with low frame-count techniques confers a significant decrease in radiation-related complications. © 2019, Tehran Heart Center. All Rights Reserved