A MEMS Singlet Oxygen Generator—Part II: Experimental Exploration of the Performance Space

This paper reports the quantitative experimental exploration of the performance space of a microfabricated singlet oxygen generator (muSOG). SOGs are multiphase reactors that mix H₂O₂, KOH, and Cl₂ to produce singlet delta oxygen, or O₂ (a). A scaled-down SOG is being developed as the pump source for a microfabricated chemical oxygen-iodine laser system because scaling down a SOG yields improved performance compared to the macroscaled versions. The performance of the muSOG was characterized using O₂ (a) yield, chlorine utilization, power in the flow, molar flow rate per unit of reactor volume, and steady-state operation as metrics. The performance of the muSOG is measured through a series of optical diagnostics and mass spectrometry. The test rig, which enables the monitoring of temperatures, pressures, and the molar flow rate of O₂ (a), is described in detail. Infrared spectra and mass spectrometry confirm the steady-state operation of the device. Experimental results reveal O₂ (a) concentrations in excess of 10¹⁷ cm^-3, O₂ (a) yield at the chip outlet approaching 80%, and molar flow rates of 02(a) per unit of reactor volume exceeding 600 times 10^-4 mol/L/s.     

Beta-lactamase inhibitors: agents to overcome bacterial resistance

Parental illness can have a profound impact on family relationships and children's behaviour. The amount and nature of communication between parents and children about the illness can play an important role, both positively and negatively, in mediating the outcomes. When children have a disability, families can be reluctant to communicate with them about family difficulties. They are often concerned about the impact that parental unavailability may have on their child's life. This paper reports on three families in which the mother was diagnosed with breast cancer and one child in the family had a disability. The extent and specific characteristics of their communication about the maternal illness with their children, behavioural changes in the children, explanations of communication strategies and attributions of behavioural changes are described. Family coping strategies are examined with reference to Lazarus's process model of stress and coping and the use of either problem-focused or emotion-focused strategies. Implications for possible clinical interventions are proposed. In particular it is suggested that families be offered consultation about: what children might understand; ways in which to communicate effectively; and strategies for coping with the long-term implications of serious parental illness.     

OXA-16, a further extended-spectrum variant of OXA-10 beta-lactamase, from two Pseudomonas aeruginosa isolates

Pooled whey from the production of one variety of ovine cheese and two varieties of caprine cheeses was studied for gross composition and individual whey protein composition over one production season. Individual proteins were quantified by sodium dodecyl sulfate-PAGE and digital imaging technology. The mean proportion of alpha-lactalbumin (LA) from caprine wheys from the manufacture of Chevre and Cheddar-type cheeses was higher than values previously reported for bovine whey from Cheddar cheese; proportions of serum albumin, immunoglobulin (Ig)G, and beta-lactoglobulin (LG) were lower. Ovine whey from Manchego-type cheese showed a higher proportion of beta-LG, about the same proportion of alpha-LA, and lower proportions of serum albumin and IgG than did the bovine whey. Relative amounts of alpha-LA decreased throughout the season, but beta-LG rose in midlactation and then gradually decreased toward the end of lactation. Relative proportions of serum albumin remained fairly stable throughout the year, and IgG decreased.     

Multi-Material ALE with AMR for Modeling Hot Plasmas and Cold Fragmenting Materials

We have developed a new 3D multi-physics multi-material code,ALE-AMR,which combines Arbitrary Lagrangian Eulerian(ALE) hydrodynamics with Adaptive Mesh Refinement(AMR) to connect the continuum to the microstructural regimes.The code is unique in its ability to model hot radiating plasmas and cold fragmenting solids.New numerical techniques were developed for many of the physics packages to work efficiently on a dynamically moving and adapting mesh.We use interface reconstruction based on volume fractions of the material components within mixed zones and reconstruct interfaces as needed.This interface reconstruction model is also used for void coalescence and fragmentation.A flexible strength/failure framework allows for pluggable material models,which may require material history arrays to determine the level of accumulated damage or the evolving yield stress in J2 plasticity models.For some applications laser rays are propagating through a virtual composite mesh consisting of the finest resolution representation of the modeled space.A new 2nd order accurate diffusion solver has been implemented for the thermal conduction and radiation transport packages.One application area is the modeling of laser/target effects including debris/shrapnel generation.Other application areas include warm dense matter,EUV lithography,and material wall interactions for fusion devices.     

CONTROLLING HIGHTEMPERATURE DEFORMATION BY VARYING MICROSTRUCTURE IN A Ti47Al2Cr2Nb ALLOY

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A MEMS Singlet Oxygen Generator—Part I: Device Fabrication and Proof of Concept Demonstration

This paper reports the design, fabrication, and proof of concept demonstration of a singlet oxygen generator (SOG) that operates on the microscale. The micro-SOG (muSOG) chip is implemented in a three-wafer stack using deep reactive ion etching (DRIE) and wafer bonding as key technologies. The device creates singlet delta oxygen (O₂(a)) in an array of packed-bed reaction channels fed by inlet manifolds with pressure drop channels that ballast the flow. An integrated capillary array separates the liquid and gas by-products, and a microscale heat exchanger removes excess heat of reaction. The fabrication process and package are designed to minimize collisional losses and wall deactivation of O₂(a). The design, fabrication, and package of the device are documented. Proof of concept demonstration of the device is given by optical emission measurements of the spontaneous decay of the O₂ (a) molecule into its triplet state and by the observation of the emission from dimol pairs of O₂ (a) molecules.     

Multicentre survey of the comparative in-vitro activity of piperacillin/tazobactam against bacteria from hospitalized patients in the British Isles

In five experiments, in which subjects were to identify a target word as it was gradually clarified, we manipulated the target's frequency of occurrence in the language and its neighborhood size--the number of words that can be constructed from a target word by changing one letter, while preserving letter position. In Experiments 1-4, visual identification performance to screen-fragmented words was measured. In Experiments 1 and 2, we used the ascending method of limits, whereas Experiments 3 and 4 presented a fixed-level fragment. In Experiment 1, there was no relation between overall accuracy and neighborhood size for words between three and six letters in length. However, more errors of commission (guesses) were made for high-neighborhood words and more errors of omission (blanks) were made for low-neighborhood words. Letter errors within guesses occurred at serial positions having many neighbors, and these positions were also likely to contain consonants rather than vowels. In Experiment 2, a small facilitatory effect of neighborhood size on both high- and low-frequency words was found. In contrast, in Experiments 3 and 4, using the same set of words, inhibitory effects of neighborhood size, but only for low-frequency words, were found. Experiment 5, using a speeded identification task, showed results parallel to those of Experiments 3 and 4. We suggest that whether neighborhood effects are facilitatory or inhibitory depends on whether feedback allows subjects to disconfirm initial hypotheses that the target is a high-frequency neighbor.