A Fullerene-Like Ball in a Second Century Roman Mosaic?

A fullerene-like ball is found in a second century mosaic from Porta Marina Roman Baths near Ostia. Although it could be an hexadecahedral ball (28 vertices, 4 hexagonal and 12 pentagonal faces), it is probably an erroneous representation of a dodecahedral ball.     

New substrates of papain, based on the conserved sequence of natural inhibitors of the cystatin family

A discontinuous borate/formate buffer system is presented for horizontal polyacrylamide gel electrophoresis of DNA fragments. The resolution potential of the system could be altered by changing the total monomer concentration (5-9%T), the concentration of the crosslinker piperazine diacrylamide (2-5%CPDA), as well as the concentration of formate in the gel (40-120 mM), the leading ion of the buffer system. The separation of DNA fragments would be improved by increasing the migration distance from 22 to 28 cm. This discontinuous polyacrylamide gel electrophoresis system proved highly reproducible.     

Hybrid Approach for Addressing Uncertainty in Risk Assessments

Parameter uncertainty is a major aspect of the model-based estimation of the risk of human exposure to pollutants. The Monte Carlo method, which applies probability theory to address model parameter uncertainty, relies on a statistical representation of available information. In recent years, other uncertainty theories have been proposed as alternative approaches to address model parameter uncertainty in situations where available information is insufficient to identify statistically representative probability distributions, due in particular to data scarcity. The simplest such theory is possibility theory, which uses so-called fuzzy numbers to represent model parameter uncertainty. In practice, it may occur that certain model parameters can be reasonably represented by probability distributions, because there are sufficient data available to substantiate such distributions by statistical analysis, while others are better represented by fuzzy numbers (due to data scarcity). The question then arises as to how these two modes of representation of model parameter uncertainty can be combined for the purpose of estimating the risk of exposure. This paper proposes an approach (termed a hybrid approach) which combines Monte Carlo random sampling of probability distribution functions with fuzzy calculus. The approach is applied to a real case of estimation of human exposure, via vegetable consumption, to cadmium present in the surficial soils of an industrial site located in the north of France. The application illustrates the potential of the proposed approach, which allows the uncertainty affecting model parameters to be represented in a way that is consistent with the information at hand. Also, because the hybrid approach takes advantage of the “rich” information provided by probability distributions, while retaining the conservative character of fuzzy calculus, it is believed to hold value in terms of a “reasonable” application of the precautionary principle.     

Perceived self-efficacy and pain control: Opioid and nonopioid mechanisms.

In this experiment, we tested for opioid and nonopioid mechanisms of pain control through cognitive means and the relation of opioid involvement to perceived coping efficacy. Subjects were taught cognitive methods of pain control, were administered a placebo, or received no intervention. Their pain tolerance was then measured at periodic intervals after they were administered either a saline solution or naloxone, an opiate antagonist that blocks the effects of endogenous opiates. Training in cognitive control strengthened perceived self-efficacy both to withstand and to reduce pain; placebo medication enhanced perceived efficacy to withstand pain but not reductive efficacy; and neither form of perceived self-efficacy changed without any intervention. Regardless of condition, the stronger the perceived self-efficacy to withstand pain, the longer subjects endured mounting pain stimulation. The findings provide evidence that attenuation of the impact of pain stimulation through cognitive control is mediated by both opioid and nonopioid mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Catalytic steam reforming of methane over La0.8Sr0.2CrO3 based Ru catalysts

La_0.8Sr_0.2CrO₃ based Ru catalysts were studied as potential new anodic materials for Solid Oxide Fuel Cells directly fed with methane and operating at intermediate temperature under water deficient conditions. Two kinds of materials very close in composition were obtained following two different preparation procedures. Catalyst samples were characterized by physicochemical methods (XRD, SEM, BET and Chemical Analysis) and studied in methane steam reforming under water deficient conditions. Carbon formation during catalytic testing was studied by temperature programmed oxidation (TPO). Both types of catalysts were found very active and resistant to carbon formation. The unusual oscillatory behavior of the catalytic activity observed for one type of catalyst was discussed.     

TLP systems with combined 50- and 500-/spl Omega/ impedance probes and Kelvin probes

Transmission line pulse (TLP) systems are mainly classified by their impedance, such as a 50- or 500-/spl Omega/ current source. A new TLP configuration allows switching between 50 and 500 /spl Omega/ by computer control to characterize a given part using both impedances. In addition, a four-needle Kelvin technique is introduced to TLP, which overcomes the measurement error from variations in contact resistance where the probe needles contact the wafer surface.     

Iron Particles Coated with Alumina: Synthesis by a Mechanofusion Process and Study of the High-Temperature Oxidation Resistance

The mechanofusion process, a dry particle coating route, has been successfully applied to coat iron particles with alumina. The high-temperature oxidation resistance of Fe and coated Fe particles has been comparatively investigated in air in the temperature range 350°–900°C. The activation energy calculations demonstrate that, in the temperature range 350°–420°C, the oxidation mechanisms are the same for both particles. Scanning electron microscopy and energy-dispersive spectroscopy analyses show that oxidation products are mainly formed at the iron/alumina interface at low temperatures or at the alumina/gas interface at high temperatures. It is shown that, depending on the temperature range, two different oxidation mechanisms are predominant.