Sub-parts-per-quadrillion-level graphite furnace atomic absorption spectrophotometry based on laser wave mixing

Nonlinear laser wave mixing in a common graphite furnace atomizer is presented as a zeptomole-level, sub-Doppler, high-resolution atomic absorption spectrophotometric method. A nonplanar three-dimensional wave-mixing optical setup is used to generate the signal beam in its own space. Signal collection is efficient and convenient using a template-based optical alignment. The graphite furnace atomizer offers advantages including fast and convenient introduction of solid, liquid, or gas analytes, clean atomization environment, and minimum background noise. Taking advantage of the unique features of the wave-mixing optical method and those of the graphite furnace atomizer, one can obtain both excellent spectral resolution and detection sensitivity. A preliminary concentration detection limit of 0.07 parts-per-quadrillion and a preliminary mass detection limit of 0.7 ag or 8 zmol are determined for rubidium using a compact laser diode as the excitation source.     

Effects of operating conditions on the removal of heavy metals by zeolite in fixed bed reactors

This work investigates the effects of flow rate (5-15 Bed Volumes/h), particle size (0.8-1.7 mm), concentration (0.005-0.02 N) and Na(+)-enrichment of natural clinoptilolite on the removal efficiency of Pb2+, Cu2+, Fe3+ and Cr3+ in aqueous solutions. Ion exchange is performed in an upflow fixed bed reactor. The removal efficiency is increased with decreasing flow rate, particle size and concentration and is improved by a factor of 2-10, depending on the specific metal. The modification of the natural sample is favorable, leading to an increase of removal efficiency by 32-100%. For the experimental conditions examined, removal efficiency order is the following: Pb2+ > Cr3+ > Fe3+ > or = Cu2+. Finally, the operation is influenced by the studied parameters, following the order: concentration > volumetric flow > rate > particle size > modification of the material.     

A game theory based approach for emergy analysis of industrial ecosystem under uncertainty

A well-designed and operated industrial ecological system should be able to utilize effectively the generated wastes from one member as the feed to another member. Nevertheless, due to heavy interactions among the member entities, particularly with various uncertainties, the coordinative material and energy reuse is a very complex task. In this paper, the issues of optimal operation of an industrial ecosystem under uncertainty are addressed. A game theory based approach is then introduced to derive an economically and environmentally optimal status of an industrial ecosystem. The effectiveness of the approach is demonstrated by tackling a case study problem, where the Nash Equilibrium for the profit payoff and sustainability payoff of the member entities is identified. The possible conflicts of the profit and sustainability objectives of the member entities in the ecosystem are resolved.     

Novel mutant human fibronectin FIII9-10 domain pair with increased conformational stability and biological activity

The ninth and tenth type III domains (FIII9–10) in thecentral cell binding domain of human fibronectin contain integrinreceptor binding sites, including RGD in FIII10 and a synergysite, PHSRN, in FIII9. The specific amino acids that contributeto cell binding have been identified by the use of wild-typeand mutant fragments of human fibronectin containing the FIII9–10domain pair. At high concentrations FIII9–10 mimics, toa large extent, the biological activity of the full-length fibronectinmolecule. However, FIII9 is conformationally unstable, evenin the context of the FIII9–10 pair. Here we report theconstruction of a series of hybrid mouse–human FIII9–10pairs that confer varying degrees of conformational stabilityto FIII9. The conformational stability of the human FIII9 modulewas increased 2–3-fold by substitution of Leu1408 withPro. We demonstrate that the biological activity of this mutantis enhanced. The resulting FIII9–10 mutant has good solutionproperties and will provide a template into which further mutationscan be incorporated in order to probe the structure–functionrelationship of the cell binding module of fibronectin.     

Adaptation of an HPLC system to quantify cholesterol

An HPLC system for separating oxidized components of crude soybean oil was adapted for use in quantifying cholesterol. At 210 nm there was linear integrator repsonse to concentration of cholesterol. The response was linear at four detector ranges, and the relationship remained linear when data were adjusted to one range. Spray-dried egg yolks contained 3,048 mg (± 117) of cholesterol per 100 g, a value similar to literature measures.     

High-Activity Heterogeneous Catalysts Prepared in One Step from the Mesophases of Metallosurfactants

Surfactant Ru(II) complexes have been used to template mesoporous silicates using the true liquid crystal templating method, giving evenly dispersed, nanometer-sized ruthenium particles which show very high catalytic activity and selectivity in the hydrogenation of 1-hexene.     

Passages of psychologists: Career stages of internship directors.

90 predoctoral internship training directors (mean age 43.3 yrs) completed a survey assessing their career stages. Five stages are identified, including entry, identity, doubt, reimmersion, and exit, and the content and time frames associated with each stage are discussed. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)