The validity of the Gammarus:Asellus ratio as an index of organic pollution: abiotic and biotic influences.

In freshwaters. Gammarus spp. are more sensitive to organic pollution than Asellus spp. and the relative abundance of the two taxa has been proposed as a pollution index. We tested the validity of this by examining the relationship between the Gammarus: Asellus (G : A) ratio and (1) a suite of physico-chemical variables. (2) established biotic (average score per taxon, ASPT) and richness (species richness (S) and Ephemeroptera, Plecoptera and Trichoptera families richness (EPT family richness)) indices generated from the macroinvertebrate community. In addition, we investigated a suspected biotic interaction, predation, between Gammarus and Asellus. Both univariate and multivariate analyses showed that the G: A ratio was sometimes responsive to changes in parameters linked to organic pollution, such as BOD5 and nitrate levels. However, the G : A ratio also appeared responsive to variables not directly linked to organic pollution, such as conductivity and distance from source. There were significant positive correlations among the G : A ratio and the ASPT, S and EPT, indicating that changes in the relative abundances of Gammarus and Asellus were reflected in changes in the pollution sensitivity and richness of the wider macroinvertebrate community. A laboratory experiment revealed significant predation of Asellus aquaticus juveniles by Gammarus duebeni celticus adults, but no reciprocal predation. We propose that the G: A ratio may be useful as a crude measure of organic pollution that could supplement more complex indices in a multimetric approach to pollution monitoring or be used for monitoring individual sites, where a simple technique is required for monitoring purposes over a period of time. Also, we urge recognition of the possible role of biotic interactions among taxa used in the generation of pollution indices.     

The Interaction of Glymes with Surfactant Micelles

The critical micelle concentrations (CMC) values and counterion dissociation (α values) have been determined for a number of mixed micellar systems consisting of two typical ionic surfactants and glycol ethers (glymes) as cosurfactants, namely diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether. Conductance experiments were used to determine the CMC and α values of the mixed micelles as a function of glyme concentration in the aqueous mixed solvent. Favorable interactions between sodium dodecyl sulfate micelles and glyme cosurfactants were deduced from the decreases in the CMC values and the large increase in the α values of these systems as a function of increasing glyme concentration in the mixed solvents. In contrast to the anionic surfactant/glyme systems, in general, there appeared to be little favorable interactions between the surfactant and glymes when micelles of the cationic surfactant dodecyltrimethylammonium bromide were formed in water/glyme solvent systems containing an increasing amount of the glymes. The interaction of glymes with the surfactant micelles was examined closely via ¹³C nuclear magnetic resonance (NMR) chemical shifts for both surfactant and glyme carbons; these chemical shifts changes were interpreted in terms of the distribution and the localization of the glymes in the aggregates. Finally, partition constants, determined from two-dimensional diffusion-oriented spectroscopy (2D-DOSY) experiments, were used to calculate thermodynamic quantities of transfer of the glymes between the bulk phase and the self-assembled aggregates. All these results are interpreted in terms of the key contributions that both the glyme ethoxylated groups and alkyl endgroups make to the hydrophobic interactions.     

A Scottish freedom of information regime for a denationalised environment: rhetorical or authentically practical?

This paper provides an evaluation of the Scottish freedom of information regime in the modern denationalised environment. The authors conducted a pragmatic investigation by means of a real-world compliance inquiry which involved, among other things, the electronic submission of standardised requests for information to those local authority arm's-length external organisations which find themselves now subject to the provisions of the Freedom of Information (Scotland) Act 2002. A compliance matrix, with several response measures, recorded the progression and outcome of the requests sent to each named ‘public authority’. The article is also furnished with a contextual overview of the interaction between the home nation FOI regimes and private enterprise with a nod to contemporaneous events. In turn, the paper reveals several quagmires for the operational practicality of FOI in the privatised arena: a pronounced reminder of the difficulties associated with maintaining a functioning and practical FOI regime in light of a myriad of public service delivery models in the denationalised epoch.     

Oocysts of Cryptosporidium parvum and model sand surfaces in aqueous solutions: an atomic force microscope (AFM) study

Oocysts of C. parvum have been associated with several waterborne outbreaks of gastro-enteric disease. Currently, one of the main barriers to oocyst contamination of drinking waters is provided by sand-bed filtration. In this study an atomic force microscope (AFM) has been used to measure the force of interaction between oocysts of C. parvum and a model sand surface (silicate glass). The AFM force curves have been compared and contrasted with the corresponding electrical potentials obtained from electrophoretic measurements (zeta). It has been found that the surface of C. parvum oocysts possesses a hairy layer, most likely a result of surface proteins extending into solution. The hairy layer imposes a steric repulsion between the oocyst and sand surface, in addition to any electrostatic repulsion. The hairy layer collapsed to varying extents in the presence of dissolved calcium and dissolved organic carbon, indicating that the oocysts may be more readily adsorbed onto the model sand surface under these conditions. Conversely, as the two surfaces are pulled apart, the occasional attachment of oocyst surface proteins to the model sand surface can result in adhesion. The AFM results offer new insights into the oocyst surface of C. parvum, and the mechanism of interaction with model sand surfaces under conditions relevant to sand-bed filtration.     

The composition and ultrastructure of sorghum spent grains

The present study aimed to investigate the composition and structure of sorghum spent grains (SSG) as a pre‐requisite for evaluating potential applications of this brewery co‐product. SSG samples sourced from African breweries employing a grist with a proportion of a hammer milled‐unmalted sorghum (Sorghum vulgare cv. Fara Fara) were found to be heterogeneous materials containing remnants of intact grains, and with particles ranging in size from <0.1 to >2 mm. Samples contained a considerable amount of residual starch (4.6–10.0% d.b.), much higher than typically reported for barley‐derived spent grains. This probably arises from the use of grists high in unmalted sorghum, but indicates that improvements in brewing process efficiency could be achieved with improvements, for example, in milling and mashing protocols. The crude protein content of the SSG samples was unexpectedly high (38.0–41.2% d.b.), indicating that this material would have potential value as an animal feed or source of refined protein. Potential reasons for this higher than expected residual protein content are discussed. The remainder of SSG gross composition (mean of five samples) was cellulose (11.4% d.b.), hemicellulose (17.3% d.b.), lipid (8.5% d.b.), lignin (9.4% d.b.) and ash (4.46% d.b.), with a total mass recovery of close to 98% represented by all analysed components. Copyright © 2013 The Institute of Brewing & Distilling     

Agents with periodontal regenerative potential regulate cell-mediated collagen lattice contraction in vitro

A variety of pharmaceutical agents has been proposed for use in periodontal therapy to inhibit loss of alveolar bone and to promote regeneration of tissues lost to disease. The purpose of this study was to determine the effects of such agents on periodontal cell-mediated gel contraction, an in vitro process considered representative of wound contraction and remodeling in vivo. Human gingival fibroblasts were cultured in a type I collagen lattice, and contraction was quantified by means of a computer-assisted video imaging system. Cell-gel combinations were prepared with cells both pre-exposed and non-exposed to agents; non-anchored cell-gels were then incubated with agents for various time periods. Agents tested included Demecolcine (an inhibitor of cytoskeletal contraction), growth factors (i.e., TGF-beta 1, PDGF, and IGF-1), and non-steroidal anti-inflammatory drugs (NSAIDs) (indomethacin, ibuprofen, naproxen, and flurbiprofen). While Demecolcine inhibited gel contraction, TGF-beta 1 (1-20 ng/mL), PDGF (100 ng/ML), IGF-1 (1000 ng/mL), and [PDGF + IGF], all of which have been reported to enhance wound healing in vivo, promoted lattice contraction in this system. In contrast, NSAIDs inhibited cell-gel contraction. Ethanol, used to solubilize two specific NSAIDs, also inhibited cell proliferation and gel contractile ability, even at very low concentrations. These findings indicate that periodontal cells respond differently to various agents in vitro and may be adversely affected by alcohol. Furthermore, the results of this study suggest that the cell-lattice contraction system holds potential as a method for screening agents for positive or negative effects on cell activity.     

Effects of inbreeding and heterozygosity on preweaning traits in a closed population of Herefords under selection

Records of five inbred lines at the Livestock and Range Research Laboratory were used to evaluate effects of inbreeding and heterozygosity on preweaning traits. Members of each line were descendants of a single founder Hereford bull. A total of 8,065 records of birth weight and 7,380 records of preweaning daily gain and weaning weight were analyzed by derivative-free REML using a model that included fixed effects of sex, combination of year and month of birth and parity of dam, with covariates for direct and maternal genetic fractions of inheritance from the genetic groups, inbreeding, and heterozygosity fractions. Heterozygosity fractions were computed for crosses between lines. The random model effects were direct and maternal genetic and uncorrelated maternal permanent environmental and temporary environmental. Direct inbreeding and heterozygosity fractions averaged .098 and .343, and maternal inbreeding and heterozygosity fractions averaged .075 and .294. Regression coefficients of traits on direct and maternal inbreeding fractions were -5.8 +/- 1.1 and -4.7 +/- 1.3 for birth weight, -.189 +/- .031 and -.252 +/- .039 for preweaning daily gain, and -44.5 +/- 6.6 and -56.1 +/- 8.4 kg for weaning weight. Estimates for direct heritability, maternal heritability, and direct-maternal genetic correlations were .37, .12, and -.01 for birth weight; .16, .25, and -.27 for daily gain; and .17, .26, and -.21 for weaning weight. Results suggest that heterosis represents recovery of accumulated inbreeding depression. Results also indicate that selection can overcome inbreeding depression and antagonism exists between direct and maternal genetic effects for preweaning traits.     

Partial agonists and full antagonists at the human and murine bradykinin B1 receptors

OBJECTIVE: To examine the incidence of first diagnosis of invasive squamous cell carcinoma (SCC) of the skin over time. DESIGN: Retrospective, population-based incidence study. SETTING: Enumerated, geographically isolated, semiurban population served by the Mayo Clinic and its affiliated hospitals and the Olmsted Medical Center, including its affiliated hospital in Rochester, Minn. METHODS: Using the Rochester Epidemiology Project databases that capture virtually all medical care provided to the residents of Rochester, we identified and reviewed records of all documented residents in whom histologically proven, invasive SCC of the skin was first diagnosed between 1984 and 1992. Age and sex stratum-specific rates were calculated, and age-adjusted rates observed over time for individuals aged 35 years or older were analyzed using Poisson regression. Adjusted rates were compared with the results of other studies. RESULTS: Review of 1630 records identified 511 incidence cases of SCC. Tumors located on the head and neck accounted for 66.4% of tumors in females and 72.9% in males. The annual age- and sex-specific incidence rates per 100,000 increased from 0 cases among males aged 0 to 14 years to 1286.0 cases among males aged 85 years or older. Over time, the annual age-adjusted incidence rates per 100,000 females rose from 46.5 (95% confidence interval [CI], 32.4-60.6) for the 1984 to 1986 period to 99.6 (95% CI, 80.4-118.7) for the 1990 to 1992 period and were 71.2 (95% CI, 61.7-80.8) overall. The corresponding rates for males were 125.9 (95% CI, 95.3-156.4), 191.0 (95% CI, 156.9-225.0), and 155.5 (95% CI, 137.0-174.0). The age- and sex-adjusted SCC incidence rates for the period from 1987 to 1989 and 1990 to 1992 exceeded those for the period from 1984 to 1986 (P = .03 and P < .001, respectively). Our age-adjusted rates for SCC were within the ranges seen in other white populations from temperate climates. CONCLUSION: The frequencies of first diagnosis of SCC are increasing at rates beyond those explainable by demographic shifts alone.     

Extreme diversity among amacrine cells: implications for function

We report a quantitative survey of the population of amacrine cells present in the retina of the rabbit. The cells' dendritic shape and level of stratification were visualized by a photochemical method in which a fluorescent product was created within an individual cell by focal irradiation of that cell's nucleus. A systematically random sample of 261 amacrine cells was examined. Four previously known amacrine cells were revealed at their correct frequencies. Our central finding is that the heterogeneous collection of other amacrine cells is broadly distributed among at least 22 types: only one type of amacrine cell makes up more than 5% of the total amacrine cell population. With these results, the program of identification and classification of retinal neurons begun by Cajal is nearing completion. The complexity encountered has implications both for the retina and for the many regions of the central nervous system where less is known.