Development of a real-time algorithm for predicting sufentanilplasma levels during cardiopulmonary-bypass surgery, using a systemsapproach

During cardiopulmonary-bypass (CB) procedures, anesthesiologists have traditionally based the administration of narcotics on general dosage recommendations and past experience. Initial doses are usually based on body weight and supplemental amounts are given in anticipation of, or in response to, the effects of surgical stimuli. There has been considerable recent interest in using the population pharmacokinetics of narcotics to optimize the attainment and maintenance of drug plasma concentrations at analgesic target levels which will blunt the hemodynamic responses to noxious stimuli. Moreover, the undershooting or overshooting of the target can be reduced by application of these principles making drug administration more effective and safer. The present study concerns the development of a model for the computer-guided administration of sufentanil throughout surgical procedures involving CB; there is a paucity of studies which have attempted to model the pharmacokinetics of drugs during CB because of the lack of information on the effects of bypass conditions on the pharmacokinetic parameters. We have attempted to approach the effects of hypothermia on sufentanil clearance by applying a continuous temperature correction to the ultimate elimination rate constant (the terminal eigenvalue). This correction is based primarily on the anticipated effects of temperature on the enzyme-catalyzed reactions which are essential for the elimination of drug from the body. An algorithm for the application of the model is also presented.     

That's Entertainment! Designing Streaming,Multimedia Web Experiences

This article investigates the use of streaming multimedia narratives in Web entertainment. Based on experience gained during the user-centered design of a Web site for art and culture, evidence is provided that users want and like "less clicking, more watching" Web experiences where the point of view of experts, artists, or celebrities is presented in a narrative form. A study was conducted where users evaluated 2 prototypes of cultural tours that stream continuously for several minutes unless the user chooses to exercise control over the flow or to explore hotlinks that lead to extra information. Those tours were positively evaluated as both entertaining and engaging. By analyzing mouse activity, it was determined that users who interacted more tended to report less entertainment and engagement. It was also found that such "watchable" experiences are not necessarily a solitary experience and can be enjoyed by groups of people. Finally, users see the Web experiences as a highly enriching and accessible way to augment the cultural experiences and performances they enjoy in brick-and-mortar cultural institutions around the world, rather than as a substitute for them.     

Establishing a sustainable and cross-boundary geospatial cyberinfrastructure to enable polar research

Polar Regions become increasingly important as places for (1) natural resources, (2) sensitive indicators of human activities and global, environment, and climate changes, (3) preserving histories of the Earth and biological evolution, and (4) space-Earth interactions and answers to many other 21st century challenges. To facilitate the research, exploration, and development for better understanding, utilizing, and protecting the Polar Regions, a Geospatial CyberInfrastructure (GCI) is needed to help us collect data, integrate information gathered or data in real time from in situ and satellite sensors, and model the geophysical, biological, ecological, and social phenomena to provide better decision support information for policymakers. This special issue of GCI and polar research captures the recent advancements in polar research and the requirements for a GCI. Through a rigorous review process, four papers were selected based on their relationships to polar research and their scientific/technical merits. This paper is a review that surveys the field, introduces the selected papers, and discusses future research.     

An Eddy-Covariance System for the Measurement of Surface/Atmosphere Exchange Fluxes of Submicron Aerosol Chemical Species—First Application Above an Urban Area

Until now, micrometeorological measurements of surface/ atmosphere exchange fluxes of submicron aerosol chemical components such as nitrate, sulfate or organics could only be made with gradient techniques. This article describes a novel setup to measure speciated aerosol fluxes by the more direct eddy covariance technique. The system is based on the Aerodyne quadrupole-based Aerosol Mass Spectrometer (Q-AMS), providing a quantitative measurement of aerosol constituents of environmental concern at a time resolution sufficient for eddy-covariance. The Q-AMS control software was modified to maximize duty cycle and statistics and enable fast data acquisition, synchronized with that of an ultrasonic anemometer. The detection limit of the Q-AMS based system for flux measurements ranges from 0.2 for NO₃ ^? to 15 ng m^?2 s^?1 for hydrocarbon-like organic aerosol (HOA), with an estimated precision of around 6 ng m^?2 s^?1, depending on aerosol loading. At common ambient concentrations the system is capable of resolving deposition velocity values < 1 mm s^?1, sufficient for measurements of dry deposition to vegetation. First tests of the system in the urban environment (6 to 20 June 2003) in Boulder, CO, USA, reveal clear diurnal, presumably traffic related, patterns in the emission of HOA and NO₃ ^?, with indication of fast production of moderately oxygenated organic aerosol below the measurement height, averaging about 15% of the HOA emission. The average emission factor for HOA was 0.5 g (kg fuel)^?1, similar to those found in previous studies. For NO₃ ^? an emission factor of 0.09 g (kg fuel)^?1 was estimated, implying oxidation of 0.5% of the traffic derived NO_x below the measurement height of 45 m. By contrast, SO₄ ^2? fluxes were on average downward, with deposition velocities that increase with friction velocity from 0.4 to 4 mm s^?1.     

International society of sports nutrition position stand: caffeine and performance

Background

We compared Glycine Propionyl-L-Carnitine (GlycoCarn^®) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO₂), blood nitrate/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men.

Methods

Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular failure). A placebo, GlycoCarn^®, or one of three dietary supplements (SUPP1, SUPP2, SUPP3) was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO₂ was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR) and rating of perceived exertion (RPE) were determined at the end of each set.

Results

A condition effect was noted for StO₂ at the start of exercise (p = 0.02), with GlycoCarn^® higher than SUPP2. A condition effect was also noted for StO₂ at the end of exercise (p = 0.003), with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p > 0.05); however, MDA decreased 13.7% with GlycoCarn^® and increased in all other conditions. Only a time effect was noted for HLa (p < 0.0001), with values increasing from pre- to post-exercise. No effects were noted for HR, RPE, or for any exercise performance variables (p > 0.05); however, GlycoCarn^® resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%), SUPP1 (4.2%), SUPP2 (2.5%), and SUPP3 (4.6%).

Conclusion

None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn^® in terms of higher StO₂ at the start of exercise. GlycoCarn^® resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1) a single ingredient (GlycoCarn^®) can provide similar practical benefit than finished products containing multiple ingredients, and 2) while we do not have data in relation to post-exercise recovery parameters, the tested products are ineffective in terms of increasing blood flow and improving acute upper body exercise performance.     

An application of the learning curve and the nonconstant-growth dividend model: IT investment valuations at Intel® Corporation

Technology benefits last years longer than the standard ROI valuation analysis but are rarely enumerated. In this paper, we utilize a nonconstant dividend growth model to “capture” lasting marginal productivity gained through the “reinvestment” of labor capital rather than the standard the one-time gain of reducing the labor force to realize labor productivity gains. This innovative methodology for capturing the productivity value of maintained employees enables the valuation of continuing marginal productivity gains and the management of workload for the affected employees at Intel. This methodology is applied to the valuation of a standard operating system and hardware upgrade.