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In this study, a Eulerian-Lagrangian model is used to study biomass gasification and release of potassium species in a 140 kW atmospheric entrained flow gasifier (EFG). Experimental measurements of water concentration and temperature inside the reactor, together with the gas composition at the gasifier outlet, are used to validate the model. For the first time, a detailed K-release model is used to predict the concentrations of gas-phase K species inside the gasifier, and the results are compared with experimental measurements from an optical port in the EFG. The prediction errors for atomic potassium (K), potassium chloride (KCl), potassium hydroxide (KOH), and total potassium are 1.4%, 9.8%, 5.5%, and 5.7%, respectively, which are within the uncertainty limits of the measurements. The numerical model is used to identify and study the main phenomena that occur in different zones of the gasifier. Five zones are identified in which drying, pyrolysis, combustion, recirculation, and gasification are active. The model was then used to study the transformation and release of different K species from biomass particles. It was found that, for the forest residue fuel that was used in the present study, the organic part of K is released at the shortest residence time, followed by the release of inorganic K at higher residence times. The release of inorganic salts starts by evaporation of KCl and continues by dissociation of K2CO3 and K2SO4, which forms gas-phase KOH. The major fraction of K is released around the combustion zone (around 0.7-1.3 m downstream of the inlet) due to the high H2O concentration and temperature. These conditions lead to rapid dissociation of K2CO3 and K2SO4, which increases the total K concentration from 336 to 510 ppm in the combustion zone. The dissociation of the inorganic salts and KOH formation continues in the gasification zone at a lower rate; hence, the total K concentration slowly increases from 510 ppm at 1.3 m to 561 ppm at the outlet.
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BACKGROUND AND OBJECTIVES: Antibiotic resistance in Pseudomonas aeruginosa is an increasing health problem. Integrons are associated with a variety of gene cassettes, which confer resistance to multiple classes of antibiotics. This study aimed at screening the presence of class 1, 2 and 3 integrons in P. aeruginosa in Yazd, Iran. MATERIALS AND METHODS: This study was carried out on P. aeruginosa strains from March 2016 to March 2017. Clinical specimens were initially identified by the standard biochemical methods and their resistance patterns to antibiotics were studied using the disc diffusion method. PCR was carried out for the detection of class 1, 2 and 3 integrons using intI1, intI2 and intI3 gene primers, respectively. RESULTS: Antimicrobial susceptibility test showed that 75% of isolates were detected as multi-drug resistant (MDR), and lowest resistance was observed in ciprofloxacin (48.6%) and most resistance was in gentamicin (63.2%). Moreover, PCR results showed that 22 (15.3%) and 119 (82.6%) of P. aeruginosa isolates carried intI2 and intI1 genes, but intI3 gene was not found. CONCLUSION: Since it is customary to observe Class I integrons in P. aeruginosa isolated from clinical samples, they are often responsible for antibiotic resistance gene transfer, which calls for evaluation of integrons as contributing factors in antibiotic resistance.
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Background: The most common entrapment mononeuropathy of the upper extremity is carpal tunnel syndrome (CTS). It consists 90% of entrapment neuropathies. The purpose of this study was to compare cross-sectional area (CSA) of the median nerve at the wrist in CTS patients and healthy controls and define the best cut-off point of CSA to differentiate patients and controls in Iranian population. Methods: In this study, 45 patients with confirmed idiopathic CTS and 62 healthy controls were evaluated. Based on electrophysiological findings, patients were divided based on CTS severity into three groups of mild, moderate and severe. The largest CSA was measured at the level of distal wrist crease which is consistent with carpal tunnel inlet. Results: Mean CSA was 0.124 ± 0.031 mm2, 0.146 ± 0.028 mm2 and 0.194 ± 0.062 mm2 in mild, moderate and severe CTS patients respectively, and 0.077 ± 0.011 mm2 in controls. Our results showed that participants with CSA > 0.010 had CTS with 100% specificity and 83.12% sensitivity. Conclusion: It is possible to diagnose CTS by measuring CSA and using above-mentioned cut-off point.
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For many years, anticoagulants have been used in the emergent treatment of patients with acute ischemic stroke. Anticoagulants are prescribed in an effort to prevent first or recurrent stroke, especially among patients with cardioembolism due to arterial fibrillation and large-artery atherosclerotic disease. Despite the widespread use, efficacy and safety of anticoagulants are controversial. Experts have given a broad spectrum of opinions. Surveys of practitioners have also demonstrated a lack of consensus on the use of anticoagulants for ischemic stroke. The uncertainty is due, in large part, to the lack of definitive clinical data. A review by the panel of the Stroke Council of the American Heart Association found no strong evidence for effectiveness of anticoagulants in treating acute ischemic stroke. Several clinical trials have suggested that utility of emergent anticoagulation has no significant effect in improving clinical outcomes for patients with acute ischemic stroke. In the present review, we have attempted to provide a framework for the emergent use of anticoagulants in acute ischemic stroke patients.