Extracting alumina from silicates by melting,quenching, and sulfuric acid leaching

More than 95% of the alumina was extracted from various silicates, such as anorthosite, clay, and kyanite, containing 30 to 45% alumina, in the melting-quenching-sulfuric acid leaching experiments conducted by the U. S. Bureau of Mines. Requirements for optimum extraction consisted of quenching the melted materials to a completely amorphous state and adjusting the weight ratio of SiO₂ to CaO + Na₂O in the quenched product within the range of about 3.0 to 3.7. At higher ratios, recovery of alumina decreased, and at lower ratios gelation of the leach-slurry ensued. The pregnant solution was readily separable from the leached residues, a basic sodium aluminum sulfate was precipitated from the solution at 200° C, by hydrolysis, and alumina was produced from the precipitate.     

Economic and energy efficiency of salvaging biomass from wildfire burnt areas for bioenergy production in northwestern Ontario: A case study

Wildfire burnt forest biomass can be salvaged as feedstock for bioenergy power generating stations. Despite availability of such forest biomass in northwestern Ontario, its procurement has generally been considered uneconomic and no studies have looked into the cost of harvesting, processing, and transporting the burnt material for bioenergy production. In order to meet the demand of biomass for proposed and existing power generating stations using renewable fuels, a standard costing model is used to determine the feasibility of procuring biomass from burnt areas using a full-tree to roadside, roadside grinder to mill system. The case-study was conducted at the Hogarth Plantations near Thunder Bay, Ontario, Canada. The total cost incurred for processing and delivery of biomass from wildfire burnt area with a hauling distance of 7 km and total trip cycle time of 2.55 h was found to be $29.65 gt^?1, with net energy content of 11.4 GJ gt^?1. The total procurement cost depends on the hauling distance and a linear relationship between the two was established. The energy analysis found a net energy output to input ratio of 35:1 for the operation.     

Long-chain n−3 polyunsaturated fatty acid incorporation into human atrium following fish oil supplementation

Recent studies have demonstrated that long-chain n−3 PUFA (LCn-3PUFA) are beneficial in reducing the risk of cardiac arrhythmias. This study was conducted to determine the extent of incorporation of LCn-3PUFA into human atrium following supplementation with a fish oil concentrate high in LCn-3PUFA. Volunteers preparing for coronary bypass surgery were randomized either to the treatment group (n=8), receiving 6 g/d of fish oil concentrate (4.4 g of LCn-3PUFA), or the placebo group (n=9), receiving 6 g/d of olive oil for a minimum period of 6 wk. Blood samples were collected prior to commencement of treatment, and preoperatively before bypass surgery. Atrial biopsies were obtained during surgery. The plasma and atrium samples were analyzed by GC following trans-methylation to determine FA profile. Post-supplementation, the treatment group had significantly higher plasma levels of 20∶5n−3, 22∶5n−3, and 22∶6n−3 than the placebo group. Analysis of the atrium total lipids revealed a significant increase in the proportion of 20∶5n−3 following fish oil supplementation. There was no significant difference in the concentration of 22∶5n−3 and 22∶6n−3 in the atrium total lipids; however, an upward trend was observed in subjects receiving fish oil supplementation. In the phospholipid fraction of the atrium, both 20∶5n−3 and 22∶6n−3 increased, whereas 20∶4n−6 levels decreased. This study demonstrates for the first time that short-term supplementation with fish oil concentrate results in significant incorporation of LNc-3PUFA with a concomitant depletion of the eicosanoid substrate (20∶4n−6) in the human atrium.     

Synergic antistaphylococcal properties of lactoferrin and lysozyme

Staphylococcus epidermidis colonises a wide range of implanted prosthetic devices, but rarely contact lenses -- despite a similarity in material composition. A conceivable explanation for this anomaly is the action of the tear defences, including the constitutive proteins lactoferrin and lysozyme. Therefore this study investigated the effect of lactoferrin, lysozyme and serum on the growth of S. epidermidis isolates in artificial tear fluid. Whether supplemented with serum alone or serum with either apolactoferrin or lysozyme, this medium induced a similar, strain-variable effect. However, simultaneous addition of these proteins induced a greater bactericidal or bacteristatic effect. Of those strains killed by the concerted action of apolactoferrin and lysozyme, the absence of serum led to a further increase in the bactericidal effect, whereas strains displaying bacteriostasis were unaffected by serum. Iron saturation of lactoferrin reversed the antimicrobial synergy of apolactoferrin and lysozyme. These results show synergy between lactoferrin and lysozyme which is dependent on the iron limitation of lactoferrin. As a bactericidal mechanism, this synergy is augmented by serum, but bacteriostasis remains unaffected by serum supplemention. Thus, the combination of lysozyme and lactoferrin may partly explain the low level of contact lens colonisation by S. epidermidis in vivo.     

Community-acquired methicillin-resistant Staphylococcus aureus in children with no identified predisposing risk

OBJECTIVE: To assess the factors that predict operative mortality after intestinal infarction, and show what effect referral patterns have on mortality. DESIGN: Retrospective study. SETTING: Two university departments of surgery, France. SUBJECTS: 144 patients with intestinal infarctions operated on between January 1980 and August 1995. INTERVENTIONS: Univariate and multivariate analyses. MAIN OUTCOME MEASURES: Operative mortality and the factors associated with it. RESULTS: Operative mortality was 67% (96/144) during the first 45 days postoperatively. The univariate analysis showed that age over 75 years (p=0.0002), female sex (p=0.007), the presence of shock (p < 0.0001), and referral from cardiovascular medical or surgical unit (p=0.01) were significantly associated with mortality. However, the multivariate analysis reduced these to extent of infarction (p=0.0001), the presence of shock (p=0.0002), age over 75 years (p=0.0001), and recent cardiac or vascular operation (p=0.03). CONCLUSIONS: The influence of referral pattern was related to previous cardiac or vascular operation, and the risk among women to the fact that their age was 10 years older than that of men. This study shows how the type of referral may explain the wide variations in reported mortality. To compare published series, care should be taken to avoid any selection bias.