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T he laryngeal mask airway (LMA) has advantages over tracheal intubation, but failure rates are a concern. The predictors of LMA failure in adults have been determined in various studies, but similar data for children are scarce. This retrospective observational study was undertaken to determine the incidence of and risk factors for LMA Unique (disposable mask) (Cardinal Health, Dublin, OH) and LMA Classic (reusable mask) (LMA North America, San Diego, CA) failure in pediatric surgical patients.The review included data on all children (<18 years old) who received a laryngeal mask anesthetic during the period 2006 to 2010, when these 2 LMAs were the only ones used at the authors' institution. All hospital-based and outpatient sites and repeat procedures were included. Variables included preoperative and intraoperative factors associated with adverse respiratory events. The primary outcome was LMA failure, defined as abandonment of the LMA and subsequent tracheal intubation. Secondary outcomes included the timing of the primary outcome relative to surgical incision and presenting features of the mask failure. SPSS version 20.0 (SPAA Inc, Chicago, Ill)was used for all analyses, with significance at P < 0.05.Of 11,921 pediatric anesthesia cases performed during the study period, 188 had an intraoperative direct laryngoscopy or placement of an endotracheal tube. Of these, 102 were actually the result of LMA failure and not changes in surgical plans, use as a rescue airway, or replaced because of communication failures. The LMA failure rate was 0.86% (~1/117 cases). Overall failure rates were substantially increased for mask sizes 1.5 and 5; other sizes were not associated with increased failure rates. Fifty-eight failures (57%) occurred before surgical incision and 44 (43%) after incision. The presenting features for LMA failure were leak or inadequate seal in 25 cases (25%). Obstruction was reported in 49 cases, in which 38 were upper airway and 11 lower airway events (37% and 10% of total, respectively). Patient intolerance reflected as hiccoughing, bucking, or coughing was the primary cause in 11 cases (11%) and a combination of these features, classified as "other" occurred in 17 cases (17%). The 5 independent predictors of LMA failure were ear/nose/throat procedure, inpatient/admit day of surgery admission status, prolonged surgical duration, congenital/acquired airway abnormality, and patient transport.These 2 LMAs have relatively low failure rates and can be used reliably in children. However, the predictors of LMA failure in children are not the same as those in adults and should be independently considered. These results should decrease the dependence on anecdotal evidence for use of LMAs in young patients. COMMENTThis article by Mathis et al is a retrospective observational study of LMA failure in children that examines clinical predictors of such failure. The authors included data on all children (<18 years old) who underwent general anesthesia with an LMA during the period 2006 to 2010. Of the 11,921 such ...

In this study, Baker's yeast strain (Saccharomyces cerevisiae) was evaluated for its ability to decolorize a synthetic dye aqueous solution and real industry effluent from Giza spinning and weaving company, Giza, Egypt. The removal of color from one of the azo dyes, ramazole blue (Vinyl sulfone), had been carried out by Baker's yeast using repeated-batch process. Factors such as solution pH, dye concentration and biomass dosage at different interval times were experimentally tested. The effect of pH on dye bioremoval was investigated at a pH range from 1 ± 0.02 to 6 ± 0.02. The optimum pH values were 2 ± 0.02, 1 ± 0.02, 3 ± 0.02, 4 ± 0.02 and 5 ± 0.02 for direct dye removal, respectively. The effect of dye concentrations was studied using different concentrations of synthetic dye containing 100-600 ppm and the effect of biomass weight was also studied at pH 2 ± 0.02 for different interval times. The equilibrium concentration and the adsorption capacity at equilibrium were determined using two different sorption models namely; Langmuir and Freundlich isotherms. These isothermal models were applied to evaluate differences in the biosorption rates and uptakes of textile dye with a high degree of correlation coefficients in case of Freundlich's isothermal model (R 2 = 0.947). At the end of the experiments, the treatment with Baker's yeast strain could reduce color absorbance and COD value of real textile wastewater by 100% and 61.82%, respectively. Baker's yeast cells were characterized using SEM and FTIR spectroscopy.

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This work represents the extraction of oil with high free fatty acid content from spent bleaching earth using sub-critical water technology as a greener production pathway. The extraction efficiencies under different conditions were investigated. The studied parameters include temperatures in the range of 180 to 270˚C, the feed to solventfeed-to-solvent (in this case water) ratio (1:1, 1:2, 1:3, 1:4 and 1:5) and extraction times in the range of 5-60 minutes. The results showed that the optimum temperature, feed to solventfeed-tosolvent ratio, and extraction time were 270˚C, 1:3, and 20 minutes, respectively. In another experiment, the extracted free fatty acids were converted into mono-, di-, and triglycerides through esterification with glycerol to increase the value added of the extracted products. The kinetics of the extraction process was found to be corresponding to an irreversible consecutive unimolecular-type first order reaction, consisting of the extraction step followed by the decomposition reaction step. Both reaction rates of extraction and decomposition were estimated using the reaction rate equations utilizing the nonlinear regression method. The apparent activation energy was calculated to be 46.1 kJ•mol −1. This result indicates a diffusion controlled reaction. For more exploration and deep understanding of the extraction mechanism, other thermodynamic parameters were also calculated and analyzed including, ∆H#, ∆S#, and ∆G# of the extraction step.

In this study, Baker's yeast strain (Saccharomyces cerevisiae) biomass was immobilized in alginate extract 3% forming Biomass/Polymer Matrices Beads (BPMB). These beads were investigated for chromium biosorption from aqueous solution. Factors such as solution pH, contact times, temperature values, stirring rates, BPMB dosages and initial chromium ions concentrations were experimentally tested using repeated-batch process to determine the sorption capacity for chromium (VI) ions. Batch experiments were conducted at pH range from 1.5 to 7.5. The optimum pH value was 3.5 for direct chromium removal. The effect of chromium concentration was studied using different concentrations from 200 to 1000 ppm. Freundlich's isothermal model showed better representation of data than Langmuir's isothermal model with correlation coefficient 0.922. The maximum biosorption capacity of chromium was found to be 154 mg g À1 at initial concentration 200 ppm under optimum conditions. At the end of the experiments, BPMB were investigated for chromium biosorption from tannery effluent sample. Results showed decrease in chromium concentration up to 85%. The availability of recycling of the BPMB was also studied for three subsequent cycles. The surface sequestration of metal ions by BPMB was characterized before and after metal binding using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray analysis (EDXA) and FTIR spectroscopy in order to determine the mechanisms of chromium biosorption. ª 2015 The Authors. Production and hosting by Elsevier B.V. on behalf of Housing and Building National Research Center. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).