Performance evaluation of canine-associated Bacteroidales assays in a multi-laboratory comparison study

The contribution of fecal pollution from dogs in urbanized areas can be significant and is an often underestimated problem. Microbial source tracking methods (MST) utilizing quantitative PCR of dog-associated gene sequences encoding 16S rRNA of Bacteroidales are a useful tool to estimate these contributions. However, data about the performance of available assays are scarce. The results of a multi-laboratory study testing two assays for the determination of dog-associated Bacteroidales (DogBact and BacCan-UCD) on 64 single and mixed fecal source samples created from pooled fecal samples collected in California are presented here. Standardization of qPCR data treatment lowered inter-laboratory variability of sensitivity and specificity results. Both assays exhibited 100% sensitivity. Normalization methods are presented that eliminated random and confirmed non-target responses. The combination of standardized qPCR data treatment, use of normalization via a non-target specific Bacteroidales assay (GenBac3), and application of threshold criteria improved the calculated specificity significantly for both assays. Such measures would reasonably improve MST data interpretation not only for canine-associated assays, but for all qPCR assays used in identifying and monitoring fecal pollution in the environment.     

Analysis of the stress and interfacial reactions in Pt/Ti/SiO2/Si for use with ferroelectric thin films

The microstructure of the Pt/Ti/SiO₂/Si structure has been investigated by scanning and transmission electron microscopy. Pt films of 100 nm thickness deposited by sputtering or evaporation onto unheated substrates gave complete coverage of the underlying Ti layer and showed a granular and faceted structure with grains ∼20 nm in diameter. They did not exhibit hillocks or surface TiO_x formation. X-ray diffraction was used to examine the film stress through use of the sin²ψ method with bulk values for the elastic constants (v=0.39, E=162 GPa). The as-deposited sputtered film had a compressive stress of ∼540 MPa, while the evaporated films had tensile stresses of ∼630 MPa. The films then received a 400°C rapid thermal anneal (RTA) for 90 s and a subsequent RTA of 650°C for 30s. Further investigation of the film stresses and microstructure were made after each annealing step. After the low temperature anneal, the film stress for the sputtered film became tensile. Plan-view sections examined by transmission electron microscopy (TEM) showed that the as-deposited sputtered films were dense but became porous after annealing. Initially, the evaporated films had a less dense microstructure, but were more stable with annealing. Little change in the stress for the evaporated film was observed after this initial low temperature annealing step. Additional annealing of the evaporated and sputtered samples caused complete consumption of the Ti layer including some TiO_x formation from the underlying SiO₂ layer and marked interaction with the Pt; however, little change in the stress was found. The surface of the Pt film revealed larger grains, but otherwise remained unaffected. The underlying phase changes were minimized once the Ti layer had reacted with the Pt. Due to the ratio of the layers, Pt:Ti of 2:1, the surface of the Pt was unaffected.     

Effect of the initial dose of foot-and-mouth disease virus on the early viral dynamics within pigs

This paper investigates the early viral dynamics of foot-and-mouth disease (FMD) within infected pigs. Using an existing within-host model, we investigate whether individual variation can be explained by the effect of the initial dose of FMD virus. To do this, we consider the experimental data on the concentration of FMD virus genomes in the blood (viral load). In this experiment, 12 pigs were inoculated with one of three different doses of FMD virus: low; medium; or high. Measurements of the viral load were recorded over a time course of approximately 11 days for every 8 hours. The model is a set of deterministic differential equations with the following variables: viral load; virus in the interstitial space; and the proportion of epithelial cells available for infection, infected and uninfected. The model was fitted to the data for each animal individually and also simultaneously over all animals varying only the initial dose. We show that the general trend in the data can be explained by varying only the initial dose. The higher the initial dose the earlier the development of a detectable viral load.     

A versatile access to new halogenated 7-azidocoumarins for photoaffinity labeling: Synthesis and photophysical properties

A versatile methodology for the synthesis of 6/8-halogenated 7-aminocoumarins from the corresponding 7-hydroxy analogs using Pd-catalyzed amination reaction as the key step is presented. Further readily conversion into 7-azidocoumarins was performed and the resulting aryl azides proved higher stability and reactivity than the corresponding non-halogenated parent compound. These new compounds may thus constitute attractive scaffolds for designing novel photoaffinity reagents for various challenging bio-labeling applications.     

Growth and aroma production by Staphylococcus xylosus, S. carnosus and S. equorum--a comparative study in model systems

A laboratory medium inoculated with 20 different Staphylococcus strains was prepared in accordance with a full factorial experimental design investigating the effect of temperature, pH, NaCl and glucose on growth. The 12 strains most suited to growth in a fermented meat environment were inoculated in sausage minces together with Pediococcus pentosaceus, incubated at 25 degrees C for 1 week and the produced aroma compounds collected. The data were analysed by multiple linear regression and partial least squares regression analysis. The results showed that increasing pH and temperature from 4.6 to 6.0 and 10 to 26 degrees C, respectively, increased growth of all strains with strong synergy between temperature and pH. Increasing salt concentration from 5% to 15% w/v decreased growth of most strains, but the effect of pH and temperature was much stronger than the effect of salt. Strains of S. carnosus were more salt tolerant than strains of S. equorum and S. xylosus, especially at high pH and temperature. Addition of glucose up to 0.5% w/v had no significant influence on growth of any of the strains. With regard to aroma production, species characteristics were detected. S. carnosus and S. xylosus were quite different regarding the overall aroma profiles, whereas the profiles of S. equorum lied somewhere in-between. Contrary to S. carnosus, S. xylosus and S. equorum did not produce 2-methyl-1-butanol. On the other hand, in particular, S. xylosus produced more 3-methyl-1-butanol. Except for one of the strains of S. equorum, S. xylosus and S. equorum formed more diacetyl, 2-butanone and acetoin and also more of the methyl-branched ketones arising from degradation of leucine, isoleucine and valine. S. carnosus produced more methyl-branched aldehydes, acids and corresponding esters from leucine, isoleucine and valine compounds that have been correlated with fermented sausage maturity in former studies. S. equorum produced the least of the methyl-branched aldehydes.     

Inferential structure of the NEO Five-Factor Inventory: Construct validity of the Big Four personality clusters.

Four studies investigated the dimensionality of the NEO Five-Factor Inventory (NEO-FFI; P. T. Costa & R. R. McCrae, 1992). In Study 1, four inferential dimensions and four clusters represented the NEO-FFI when 114 undergraduates freely sorted items into categories. Construct validity for four item-clusters derived from the inferential space was obtained in Study 2 based on self-report with 304 undergraduates. Study 3 validated these inferential clusters using self and peer reports for 420 undergraduates. Study 4 validated the cluster scales for predicting quality of life and significant social and cultural behaviours for 110 undergraduates. Implications for implicit personality theory, the number of dimensions issue in personality, and test construction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Listening to parents' voices: Participatory action research in the schools.

How can schools and parents work together more effectively? This article describes a participatory action research (PAR) project with a group of parents whose children had been classified as having emotional disabilities. As the parents shared their stories of trying to navigate the special education system, they developed critical consciousness about their experiences of stress, powerlessness, and alienation. They became mobilized and obtained information about testing, diagnostic classification, and educational options for their children. Armed with this information, they developed and implemented an action plan to improve family-school relationships at the local, community, and state levels. The article concludes with an example of how the PAR model can be exported to a variety of mental health settings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)