Computer-aided tools for pollution prevention: solvent-based processes

 This paper provides an analysis of pollution prevention, treatment and cure with respect to solvent-based processes. It is postulated that, in new processes, considering environmental constraints in the early stages of process design can prevent pollution due to inefficient recovery of solvents or inefficient separation by solvents. Pollution in existing processes can also be prevented through early treatment that includes assessment of causes and effects of future changes in process conditions and/or environmental regulations. Pollution cure is more difficult, since the process is already violating some environmental constraints and any solution also needs to satisfy social and economic constraints. A technique for pollution prevention, treatment and cure that is based on the use of computer-aided tools is presented. Application of the technique is illustrated through a case study that highlights the important steps of the solution approach and serves as a proof of concept. Received: 13 July 1999 / Accepted: 3 November 1999     

Long-term inhalable particles and other air pollutants related to mortality in nonsmokers

Long-term ambient concentrations of inhalable particles less than 10 microm in diameter (PM10) (1973- 1992) and other air pollutants-total suspended sulfates, sulfur dioxide, ozone (O3), and nitrogen dioxide-were related to 1977-1992 mortality in a cohort of 6,338 nonsmoking California Seventh-day Adventists. In both sexes, PM10 showed a strong association with mortality for any mention of nonmalignant respiratory disease on the death certificate, adjusting for a wide range of potentially confounding factors, including occupational and indoor sources of air pollutants. The adjusted relative risk (RR) for this cause of death as associated with an interquartile range (IQR) difference of 43 d/yr when PM10 exceeded 100 microg/m3 was 1.18 (95% confidence interval [CI]: 1.02, 1.36). In males, PM10 showed a strong association with lung cancer deaths-RR for an IQR was 2.38 (95% CI: 1.42, 3.97). Ozone showed an even stronger association with lung cancer mortality for males with an RR of 4.19 (95% CI: 1.81, 9.69) for the IQR difference of 551 h/yr when O3 exceeded 100 parts per billion. Sulfur dioxide showed strong associations with lung cancer mortality for both sexes. Other pollutants showed weak or no association with mortality.     

Reasoning about necessity and possibility: A test of the mental model theory of deduction.

This article examined syllogistic reasoning in college students that differs from previous research in 2 significant ways: (a) Participants were asked to decide whether conclusions were possible as well as necessary, and (b) every possible combination of syllogistic premises and conclusions was presented for evaluation with both single-premise (Experiment 1) and double-premise (Experiment 2) problems. Participants more frequently endorsed conclusions as possible than as necessary, and differences in response to the 2 forms of instruction conformed to several predictions derived from the mental model theory of deduction. Findings of Experiments 2 and 3 showed that some fallacies are consistently endorsed and others consistently resisted when people are asked to judge whether conclusions that are only possible follow necessarily. This finding was accounted for by the computational implementation of the model theory: Fallacies are made when the first mental model of the premises considered supports the conclusion presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The moisture absorption of glass fibre reinforced vinylester and polyester composites

The water absorption characteristics of unidirectional glass reinforced vinylester and polyester laminates in distilled water and in 95% relative humidity at 25°C, 50°C, 60°C and 70°C were investigated. The results show that the calculated values and the experimental data agree reasonably well, but deviation occurred at higher temperatures.     

Methylphenidate and baseball playing in ADHD children: Who's on first?

The effects of 0.3 and 0.6 mg/kg methylphenidate were analyzed in a double-blind, placebo-controlled, cross-over study in which 17 boys (ages 7.8–9.9 yrs) with attention deficit hyperactivity disorder (ADHD) played in baseball games. Drug effects were evaluated on children's attention during the game, as indictated by their on-task behavior on the field and their ability to answer questions about the status of the game at all times. Judgment during batting, batting skill during the game, and performance on skill drills prior to the game were also assessed as a function of medication. Results revealed that methylphenidate had a beneficial effect on attending during the game. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Atomic force microscopic imaging of seeded fibril formation and fibril branching by the Alzheimer's disease amyloid-beta protein

BACKGROUND: Amyloid plaques composed of the fibrillar form of the amyloid-beta protein (Abeta) are the defining neuropathological feature of Alzheimer's disease (AD). A detailed understanding of the time course of amyloid formation could define steps in disease progression and provide targets for therapeutic intervention. Amyloid fibrils, indistinguishable from those derived from an AD brain, can be produced in vitro using a seeded polymerization mechanism. In its simplest form, this mechanism involves a cooperative transition from monomeric Abeta to the amyloid fibril without the buildup of intermediates. Recently, however, a transient species, the Abeta amyloid protofibril, has been identified. Here, we report studies of Abeta amyloid protofibril and its seeded transition into amyloid fibrils using atomic force microscopy. RESULTS: Seeding of the protofibril-to-fibril transition was observed. Preformed fibrils, but not protofibrils, effectively seeded this transition. The assembly state of Abeta influenced the rate of seeded growth, indicating that protofibrils are fibril assembly precursors. The handedness of the helical surface morphology of fibrils depended on the chirality of Abeta. Finally, branched and partially wound fibrils were observed. CONCLUSIONS: The temporal evolution of morphologies suggests that the protofibril-to-fibril transition is nucleation-dependent and that protofibril winding is involved in that transition. Fibril unwinding and branching may be essential for the post-nucleation growth process. The protofibrillar assembly intermediate is a potential target for AD therapeutics aimed at inhibiting amyloid formation and AD diagnostics aimed at detecting presymptomatic disease.