Assessing the sensitivity and specificity of fish community indicators to management action

We assessed ten trophodynamic indicators of ecosystem status for their sensitivity and specificity to fishing management using a size-resolved multispecies fish community model. The responses of indicators to fishing depended on effort and the size selectivity (sigmoid or Gaussian) of fishing mortality. The highest specificity against sigmoid (trawl-like) size selection was seen from inverse fishing pressure and the large fish indicator, but for Gaussian size selection, the large species indicator was most specific. Biomass, mean trophic level of the community and of the catch, and fishing in balance had the lowest specificity against both size selectivities. Length-based indicators weighted by biomass, rather than abundance, were more sensitive and specific to fishing pressure. Most indicators showed a greater response to sigmoid than Gaussian size selection. Indicators were generally more sensitive at low levels of effort because of nonlinear sensitivity in trophic cascades to fishing mortality. No single indicator emerged as superior in all respects, so given available data, multiple complementary indicators are recommended for community monitoring in the ecosystem approach to fisheries management.

Secretion and processing of a novel multi-domain cystatin-like protein by intracellular stages of Trichinella spiralis

The excretory-secretory (ES) proteins of nematode parasites are of major interest as they function at the host-parasite interface and are likely to have roles crucial for successful parasitism. Furthermore, the ES proteins of intracellular nematodes such as Trichinella spiralis may also function to regulate gene expression in the host cell. In a recent proteomic analysis we identified a novel secreted cystatin-like protein from T. spiralis L1 muscle larva. Here we show that the protein, MCD-1 (multi-cystatin-like domain protein 1), contains three repeating cystatin-like domains and analysis of the mcd-1 gene structure suggests that the repeated domains arose from duplication of an ancestral cystatin gene. Cystatins are a diverse group of cysteine protease inhibitors and those secreted by parasitic nematodes are important immuno-modulatory factors. The cystatin superfamily also includes cystatin-like proteins that have no cysteine protease inhibitory activity. A recombinant MCD-1 protein expressed as a GST-fusion protein in Escherichia coli failed to inhibit papain in vitro suggesting that the T. spiralis protein is a new member of the non-inhibitory cystatin-related proteins. MCD-1 secreted from T. spiralis exists as high- and low-molecular weight isoforms and we show that a recombinant MCD-1 protein secreted by HeLa cells undergoes pH-dependent processing that may result in the release of individual cystatin-like domains. Furthermore, we found that mcd-1 gene expression is largely restricted to intracellular stages with the highest levels of expression in the adult worms. It is likely that the major role of the protein is during the intestinal stage of T. spiralis infections.

Optimization of the processing of HNBR/organoclay nanocomposite

In the current investigation, rubber/clay nanocomposites were prepared by two different methods using hydrogenated nitrile butadiene rubber (HNBR) and the organoclay namely Cloisite 15A (C15A). A new novel approach involving swelling of C15A by ulltrasonication in HNBR solution has been carried out for improving the exfoliation and compatibilization of organoclays with HNBR matrix. With the addition of 5phr of clay, the elongation at break and tear strength improved by 16% and 24% respectively. The effect of coupling agents namely amino functional silane and tetrasulfido silane on the nanocomposites have been investigated. The elongation at break and tear strength improved by 46% and 77% respectively with the use of silanes. The improvement in the mechanical properties attributes to improved interaction between the organoclays and HNBR matrix. This interaction has been studied by X-ray diffraction and transmission electron microscope. Pre-dispersion technique clearly suggests very good improvement in the dispersion and properties due to better filler-rubber compatibility. © 2010 American Institute of Physics.

Processing of short auditory stimuli:The rapid audio sequential presentation paradigm (RASP)

Human listeners seem to be remarkably able to recognise acoustic sound sources based on timbre cues. Here we describe a psychophysical paradigm to estimate the time it takes to recognise a set of complex sounds differing only in timbre cues: both in terms of the minimum duration of the sounds and the inferred neural processing time. Listeners had to respond to the human voice while ignoring a set of distractors. All sounds were recorded from natural sources over the same pitch range and equalised to the same duration and power. In a first experiment, stimuli were gated in time with a raised-cosine window of variable duration and random onset time. A voice/non-voice (yes/no) task was used. Performance, as measured by d', remained above chance for the shortest sounds tested (2 ms); d's above 1 were observed for durations longer than or equal to 8 ms. Then, we constructed sequences of short sounds presented in rapid succession. Listeners were asked to report the presence of a single voice token that could occur at a random position within the sequence. This method is analogous to the "rapid sequential visual presentation" paradigm (RSVP), which has been used to evaluate neural processing time for images. For 500-ms sequences made of 32-ms and 16-ms sounds, d' remained above chance for presentation rates of up to 30 sounds per second. There was no effect of the pitch relation between successive sounds: identical for all sounds in the sequence or random for each sound. This implies that the task was not determined by streaming or forward masking, as both phenomena would predict better performance for the random pitch condition. Overall, the recognition of familiar sound categories such as the voice seems to be surprisingly fast, both in terms of the acoustic duration required and of the underlying neural time constants.

Production and Processing of Spider Silk Proteins

Natural spider silk fibers have impressive mechanical properties (outperforming many man-made fibers) and are, moreover, biocompatible, biodegradable, and produced under benign conditions (using water as a solvent at ambient temperature). The problems associated with harvesting natural spider silks inspired us to devise a method to produce spider silk-like proteins biotechnologically (the first subject tackled in this highlight); we subsequently discuss their processing into various materials morphologies, and some potential technical and biomedical applications.

Losses of bioactive polyacetylenes during minimal processing of carrots

Vegetables of the Apiaceae plant family such as carrots, parsnip, celery and parsley,contain in minor quantities, a group of bioactive aliphatic C17-polyacetylenes (falcarinol,falcarindiol, falcarindiol-3- acetate). Recent studies have highlighted important biologicalfunctions in vitro and in vivo (animal studies) although the beneficial effect in humannutrition attributable to an increased in polyacetylenes diet are yet to be confirmed(Lund, 1990).Carrots not only contain relatively high polyacetylene content but also form a significantpart of many countries dietary habits. Carrots are also present in some ready-to-eat foodssuch as chilled freshly prepared salads, as part of the increasingly popular minimallyprocessed foods. Whereas the effect of conventional processing (boiling, vacuum processing) on the levels of polyacetylenes has been relatively well studied, the effect of minimal mechanical operations such as “peeling”, “mechanical cutting” and “chlorine washing” remains unknown.

Atmospheric Pressure DC Plasma Processing of TIO2/PEDOT:PSS Nanocomposites

In this work we demonstrate the synthesis of a TiO2/PEDOT:PSS nanocomposite material in aqueous solution through atmospheric pressure direct current (DC) plasma processing at room temperature. The dispersion of the TiO2 nanoparticles is enhanced after microplasma processing, and TiO2/polymer hybrid nanoparticles with a distinct core shell structure have been obtained. We have observed increased TiO2/PEDOT:PSS nanocomposite electrical conductivity due to microplasma processing. The improvement in nanocomposite properties is due to the enhanced dispersion and stability in liquid polymer of microplasma treated TiO2 nanoparticles. Both plasma induced surface charge and nanoparticle surface termination with specific plasma chemical species are thought to provide an enhanced barrier to nanoparticle agglomeration and promote nanoparticle-polymer bonding, which is expected to have a significant benefit in materials processing with inorganic nanoparticles for wide range of applications.

Dissolution and processing of cellulose using ionic liquids, cellulose solution, and regenerating cellulose.

Cellulose is dissolved in an ionic liq. without derivatization, and is regenerated in a range of structural forms without requiring the use of harmful or volatile org. solvents. Cellulose soly. and the soln. properties can be controlled by the selection of the ionic liq. constituents, with small cations and halide or pseudohalide anions favoring soln.; dissoln. can be aided by irradn. An ionic liq., [C4mim]Cl, proved to be the best for dissolving cellulose. [on SciFinder(R)]

Characterisation and modelling of the thermorheological properties of pharmaceutical polymers and their blends using capillary rheometry: Implications for hot melt processing of dosage forms.

Given the growing interest in thermal processing methods, this study describes the use of an advanced rheological technique, capillary rheometry, to accurately determine the thermorheological properties of two pharmaceutical polymers, Eudragit E100 (E100) and hydroxypropylcellulose JF (HPC) and their blends, both in the presence and absence of a model therapeutic agent (quinine, as the base and hydrochloride salt). Furthermore, the glass transition temperatures (Tg) of the cooled extrudates produced using capillary rheometry were characterised using Dynamic Mechanical Thermal Analysis (DMTA) thereby enabling correlations to be drawn between the information derived from capillary rheometry and the glass transition properties of the extrudates. The shear viscosities of E100 and HPC (and their blends) decreased as functions of increasing temperature and shear rates, with the shear viscosity of E100 being significantly greater than that of HPC at all temperatures and shear rates. All platforms were readily processed at shear rates relevant to extrusion (approximately 200–300 s−1) and injection moulding (approximately 900 s−1). Quinine base was observed to lower the shear viscosities of E100 and E100/HPC blends during processing and the Tg of extrudates, indicative of plasticisation at processing temperatures and when cooled (i.e. in the solid state). Quinine hydrochloride (20% w/w) increased the shear viscosities of E100 and HPC and their blends during processing and did not affect the Tg of the parent polymer. However, the shear viscosities of these systems were not prohibitive to processing at shear rates relevant to extrusion and injection moulding. As the ratio of E100:HPC increased within the polymer blends the effects of quinine base on the lowering of both shear viscosity and Tg of the polymer blends increased, reflecting the greater solubility of quinine within E100. In conclusion, this study has highlighted the importance of capillary rheometry in identifying processing conditions, polymer miscibility and plasticisation phenomena.

Suitability, efficiency and microbiological safety of novel physical technologies for the processing of ready-to-eat meals, meats and pumpable products

Consumer studies and market reports show an increase in consumption of ready-to-eat (RTE) foods. Although conventional processing technologies can in most cases produce safe products, they can also lead to the degradation of nutritional compounds and negatively affect quality characteristics. Consumers strongly prefer food that is minimally processed with the maximum amount of health-promoting substances. Novel processing technologies as pre- or post-treatment decontamination methods or as substitutes of conventional technologies have the potential to produce foods that are safe, rich in nutrient content and with superior organoleptic properties. Combining novel with conventional processes can eliminate potential drawbacks of novel technologies. This review examines available scientific information and critically evaluates the suitability and efficiency of various novel thermal and nonthermal technologies in terms of microbial safety, quality as well as nutrient content on the production of RTE meals, meats and pumpable products.

Efficient Processing of Spatial Group Keyword Queries

With the proliferation of geo-positioning and geo-tagging techniques, spatio-textual objects that possess both a geographical location and a textual description are gaining in prevalence, and spatial keyword queries that exploit both location and textual description are gaining in prominence. However, the queries studied so far generally focus on finding individual objects that each satisfy a query rather than finding groups of objects where the objects in a group together satisfy a query.

We define the problem of retrieving a group of spatio-textual objects such that the group's keywords cover the query's keywords and such that the objects are nearest to the query location and have the smallest inter-object distances. Specifically, we study three instantiations of this problem, all of which are NP-hard. We devise exact solutions as well as approximate solutions with provable approximation bounds to the problems. In addition, we solve the problems of retrieving top-k groups of three instantiations, and study a weighted version of the problem that incorporates object weights. We present empirical studies that offer insight into the efficiency of the solutions, as well as the accuracy of the approximate solutions.

Variations in the Processing of DNA Double-Strand Breaks Along 60-MeV Therapeutic Proton Beams

PURPOSE: To investigate the variations in induction and repair of DNA damage along the proton path, after a previous report on the increasing biological effectiveness along clinically modulated 60-MeV proton beams.

METHODS AND MATERIALS: Human skin fibroblast (AG01522) cells were irradiated along a monoenergetic and a modulated spread-out Bragg peak (SOBP) proton beam used for treating ocular melanoma at the Douglas Cyclotron, Clatterbridge Centre for Oncology, Wirral, Liverpool, United Kingdom. The DNA damage response was studied using the 53BP1 foci formation assay. The linear energy transfer (LET) dependence was studied by irradiating the cells at depths corresponding to entrance, proximal, middle, and distal positions of SOBP and the entrance and peak position for the pristine beam.

RESULTS: A significant amount of persistent foci was observed at the distal end of the SOBP, suggesting complex residual DNA double-strand break damage induction corresponding to the highest LET values achievable by modulated proton beams. Unlike the directly irradiated, medium-sharing bystander cells did not show any significant increase in residual foci.

CONCLUSIONS: The DNA damage response along the proton beam path was similar to the response of X rays, confirming the low-LET quality of the proton exposure. However, at the distal end of SOBP our data indicate an increased complexity of DNA lesions and slower repair kinetics. A lack of significant induction of 53BP1 foci in the bystander cells suggests a minor role of cell signaling for DNA damage under these conditions.