Mycobacterium avium ssp. paratuberculosis: its incidence, heat resistance and detection in milk and dairy products

Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease in cattle and other ruminants and has been implicated as a possible cause of Crohn's disease in humans. The organism gains access to raw milk directly through excretion into the milk within the udder, and indirectly through faecal contamination during milking. MAP has been shown to survive commercial pasteurization in naturally infected milk, even at the extended holding time of 25 s. Pasteurized milk must therefore be considered a vehicle of transmission of MAP to humans. Isolation methods for MAP from milk are problematical, chiefly because of the absence of a suitable selective medium. This makes food surveillance programs and research on this topic difficult. The MAP problem can be addressed in two main ways: by devising a milk-processing strategy that ensures the death of the organism; and/or strategies at farm level to prevent access of the organism into raw milk. Much of the research to date has been devoted to determining if a problem exists and, if so, the extent of the problem. Little has been directed at possible solutions. Given the current state of information on this topic and the potential consequences for the dairy industry, research is urgently needed so that a better understanding of the risks and the efficacy of possible processing solutions can be determined.     

A WENO-Solver for the 1D Non-Stationary Boltzmann–Poisson System for Semiconductor Devices

In this work we present preliminary results of a high order WENO scheme applied to a new formulation of the Boltzmann equation (BTE) describing electron transport in semiconductor devices with a spherical coordinate system for the phase velocity space. The problem is two dimensional in the phase velocity space and one dimensional in the physical space, plus the time variable driving to steady states. The new formulation avoids the singularity due to the spherical coordinate system.     

Nicotine pharmacokinetics and subjective effects of three potential reduced exposure products, moist snuff and nicotine lozenge

Objective

To compare nicotine pharmacokinetics and subjective effects of three new smokeless tobacco potential reduced exposure products (PREPs; Ariva, Revel and Stonewall) with moist snuff (Copenhagen) and medicinal nicotine (Commit lozenge).

Methods

10 subjects completed a randomised, within‐subject, crossover study. Subjects used one product for 30 min at each of the five laboratory sessions. Maximal nicotine concentration (C_max) was determined and area under the concentration time curve (AUC) was calculated for a 90‐min period (during use and 60 min after use). Nicotine craving, withdrawal symptoms and ratings of product effects and liking were measured during product use.

Results

Nicotine AUC and C_max were higher for Copenhagen than for any other product (p<0.002) and higher for Commit than for either Ariva or Revel (p<0.001). C_max for Commit was also higher than for Stonewall (p = 0.03). Craving was lowest during use of Copenhagen (p<0.03). Craving during use of Stonewall, Ariva and Commit was lower than during use of Revel (p<0.05). Withdrawal symptom score during use of Copenhagen was lower than during use of Revel (p = 0.009). Copenhagen scores were higher (p<0.005) than all other products in several measures of drug effects and liking (feel good effects, satisfaction, liking and desire for product, and strength of product).

Conclusion

The new smokeless tobacco PREPs result in lower nicotine concentrations and equivalent or lower reductions in subjective measures compared with medicinal nicotine. Since health effects of PREPs are largely unknown, medicinal nicotine should be preferentially encouraged for smokers or smokeless tobacco users wishing to switch to lower‐risk products.Over the past several years, a number of new tobacco products have been introduced, some of which are being marketed, either implicitly or explicitly, as having reduced toxicant exposure or decreased health risks. To assist in evaluating these potential reduced exposure products (PREPs), the United States Food and Drug Administration in 1999 asked the Institute of Medicine to formulate methods and standards by which PREPs could be assessed.¹ More recently, an expert panel was convened to develop guidelines for the evaluation of PREPs on both individual and population levels. Among the topics addressed was human clinical testing, which included recommendations on methods and biomarkers to assess PREPs.^2,3 The recommended evaluation of PREPs included conducting studies on the pharmacokinetic properties of the products and assessing misuse liability by measuring subjective responses to the products and ability of the products to suppress withdrawal.³The use of smokeless tobacco products, in lieu of cigarettes, has been suggested as a promising method by which to reduce tobacco‐related health consequences.⁴ Currently, tobacco companies including major cigarette‐manufacturing companies are test marketing smokeless and spitless tobacco products (eg, Camel Snus by Reynolds American, Taboka by Philip Morris) as a substitute for smoking. Although overall morbidity and mortality associated with the use of moist snuff or chewing tobacco is lower than the risks associated with cigarette smoking, health consequences such as increased rates of oral and pancreatic cancers remain.^5,6 Furthermore, health effects of all forms of smokeless tobacco are not equivalent. For example, an evaluation of the content of tobacco‐specific nitrosamines found large differences between the various forms and brands of smokeless tobacco.⁷ In a human study, a significant decrease in the uptake of tobacco carcinogens has been observed when users of conventional brands of smokeless tobacco switch to Swedish snus.⁸ A comparison of several brands of moist snuff products found significant differences between brands in the amount of unionised (free) nicotine^9,10,11 and in exposure to nicotine and heart rate response after use of a single dose of each product.¹² To accurately assess the potential health effects of a product and the factors associated with consumer use, it is therefore necessary to test each smokeless tobacco product individually, including evaluating the nicotine pharmacokinetics.The purposes of this study were to assess the pharmacokinetics and subjective responses of smokeless tobacco users when using three new PREPs and to compare them with a commonly used brand of moist snuff (Copenhagen) and the medicinal nicotine lozenge (4 mg Commit). The new smokeless tobacco products studied were (1) Ariva, a compressed powdered tobacco lozenge manufactured to contain low tobacco‐specific nitrosamines by Star Scientific marketed for use by smokers when they cannot or choose not to smoke; (2) Stonewall, another compressed powdered low tobacco‐specific nitrosamine tobacco lozenge from Star Scientific marketed as a spit‐free alternative for users of traditional moist snuff smokeless tobacco products; and (3) Revel, a spit‐free smokeless tobacco packet marketed by US Smokeless Tobacco for smokers seeking a discrete alternative to smoking.     

GIS approach to the definition of capacity and generation ceilings of renewable energy technologies

There are no discrepancies about the advantages of achieving a sustainable energy system based on locally available natural resources. However, supporters of green energy generation system were lacking some scientific and consistent study to defend their proposals. In order to have such a study, Greenpeace commissioned Technology Research Institute at the Pontificia Comillas University to carry out a study to assess ceilings for the potential and generation of renewable technologies in Spain. It demonstrates firstly a far greater renewable potential than the targets set by long term policies, and secondly, the viability of meeting the entire electricity demand projected for 2050. GIS was used to add the geographical dimension to the original project in order to generate a technical analysis linked to the specific constrictions imposed by territory (natural and anthropogenic) and not just designed to cover a certain demand. Therefore, GIS spatial analysis took into account local conditions producing a more accurate assessment than evaluations made upon “virtual” electrical spaces. This approach could be applied to other small scale general studies in order to assess the maximum contribution of renewable energy sources to particular energy generation mix and to help set development policies supporting high participation of renewable technologies.     

Solvent processible, high-performance partially fluorinated copoly(arylene ether) alkaline ionomers for alkaline electrodes

A solvent processable, low water uptake, partially fluorinated copoly(arylene ether) functionalized with pendant quaternary ammonium groups (QAPAE) was synthesized and uses as the ionomer in alkaline electrodes on fuel cells. The quaternized polymers containing fluorinated biphenyl groups were synthesized via chloromethylation of copoly(arylene ether) followed by amination with trimethylamine. The resulting ionomers were very soluble in polar, aprotic solvents. Highly aminated ionomers had conductivities approaching 10 mS cm⁻¹ at room temperature. Compared to previous ionomers based on quaternized poly(arylene ether sulfone) (QAPSF) with similar ion exchange capacity (IEC), the water uptake of QAPAE was significantly less due to the hydrophobic octafluoro-biphenyl groups in the backbone. The performance of the fuel cell electrodes made with the QAPAE ionomers was evaluated as the cathode on a hybrid AEM/PEM fuel cell. The QAPAE alkaline ionomer electrode with IEC = 1.22 meq g⁻¹ had superior performance to the electrodes prepared with QAPSF, IEC = 1.21 meq g⁻¹ at 25 and 60 °C in a H₂/O₂ fuel cell. The peak power densities at 60 °C were 315 mW cm⁻² for QAPAE electrodes and 215 mW cm⁻² for QAPSF electrodes.     

Redistribution of phosphoric acid in membrane electrode assemblies for high-temperature polymer electrolyte fuel cells

We demonstrate that the performance of a high-temperature polymer electrolyte fuel cell with a phosphoric acid-based electrolyte is almost independent of the way of introducing the acid into the membrane electrode assembly (MEA). The same power densities were obtained with different MEAs in which the poly(2,5-benzimidazole) membrane was either pre-doped or not and in which either one or two catalyst layers were impregnated with H₃PO₄. Chemical analysis after shut down revealed that in all these MEAs the phosphoric acid distribution between the membrane and the electrodes was nearly the same. An MEA with acid impregnation via the electrodes was started up rapidly from room temperature, delivered a power density of 120 mW cm⁻² at 600 mV (H₂/air, 160 °C, ambient pressure) after only 11 min and was operated for 1000 h (degradation rate: 0.06 mV/h). Based on the analysis of the H₃PO₄ content in the MEA components, reflections on the kinetics of the redistribution of phosphoric acid within the MEA are provided.     

Ageism in undergraduate psychology texts.

A sample of 139 texts written over the past 40 yrs was analyzed for evidence of ageism (i. e., lack of attention to the psychology of later life and stereotyping of older adults). More recent texts cover the topic more comprehensively than in the past, but this coverage is limited in depth. Although textbook authors appear to be trying to communicate a positive message about aging and older persons, their efforts are compromised by ambivalence in the form of contradictory statements about the nature of the aging process. There is an unfortunate condensation of sources in recent texts which draw heavily from a small cluster of authorities. Implications of these findings for the larger textbook enterprise are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discontinuity and correlation: A reply to Eysenck.

"Our original point was to underscore Eysenck's own carefully stated reservations concerning the application of criterion analysis. We erred in not making this sufficiently clear. Here, we have tried to rectify this error and to amplify a suggestion made implicitly in the earlier paper (see 33: 1700), for an experimental approach to the validation of factor analytic procedures in relation to discrete genotypic determinants of human behavior." (PsycINFO Database Record (c) 2010 APA, all rights reserved)