Mobile Bay turbidity study

The termination of studies carried on for almost three years in the Mobile Bay area and adjacent continental shelf are reported. The initial results concentrating on the shelf and lower bay were presented in the interim report. The continued scope of work was designed to attempt a refinement of the mathematical model, assess the effectiveness of optical measurement of suspended particulate material and disseminate the acquired information. The optical characteristics of particulate solutions are affected by density gradients within the medium, density of the suspended particles, particle size, particle shape, particle quality, albedo, and the angle of refracted light. Several of these are discussed in detail

Chromatographic separation and identification of some peptides in partial hydroylsates of gelatin

Recently we have been engaged in a study of the chemical structure of collagen and gelatin with the object of determining the sequence of the amino acid residues in the polypeptide chains of these proteins. In the course of this study we have made considerable progress in the chromatographic analysis of complex mixtures of peptides and we have isolated and identified several simple peptides which occur in partial hydrolysates of gelatin. The initial separation of the mixture into zones of one or more peptides has been made on a column of ion exchange resin; further separation of the peptides in each zone has been achieved by chromatographing in the form of dinitrophenyl (DNP) peptides on columns of silicic acid-Celite. It is to be hoped that the particular combination of chromatographic methods which has been successfully used in the present study will be helpful in the resolution of the complex mixtures which result from the partial hydrolysis of other proteins

Recent Advances In Technics For The Study Of Viruses

The existence of viruses was suspected by Pasteur but it was not until 1897 that active work was begun on these agents. At this time Loeffler and Foesche demonstrated the existence of the virus of foot and mouth disease. Early workers depended upon the filter for the isolation of viruses and an attempt was made to grow viruses in artificial tissue cultures. Diagnostic tests were dependent upon the complement-fixation test and animal protection and neutralization tests

Ultrathin oxides: bulk-oxide-like model surfaces or unique films?

To better understand the electronic and chemical properties of wide-gap oxide surfaces at the atomic scale, experimental work has focused on epitaxial films on metal substrates. Recent findings show that these films are considerably thinner than previously thought. This raises doubts about the transferability of the results to surface properties of thicker films and bulk crystals. By means of density-functional theory and approximate GW corrections for the electronic spectra we demonstrate for three characteristic wide-gap oxides (silica, alumina, and hafnia) the influence of the substrate and highlight critical differences between the ultrathin films and surfaces of bulk materials. Our results imply that monolayer-thin oxide films have rather unique properties.Comment: 5 pages, 3 figures, accepted by PR

The complex channel networks of bone structure

Bone structure in mammals involves a complex network of channels (Havers and Volkmann channels) required to nourish the bone marrow cells. This work describes how three-dimensional reconstructions of such systems can be obtained and represented in terms of complex networks. Three important findings are reported: (i) the fact that the channel branching density resembles a power law implies the existence of distribution hubs; (ii) the conditional node degree density indicates a clear tendency of connection between nodes with degrees 2 and 4; and (iii) the application of the recently introduced concept of hierarchical clustering coefficient allows the identification of typical scales of channel redistribution. A series of important biological insights is drawn and discussedComment: 3 pages, 1 figure, The following article has been submitted to Applied Physics Letters. If it is published, it will be found online at http://apl.aip.org

An exploration of the attitudes and perceptions of the UK public towards self-care for minor ailments

Aims and objectives: The purpose of this pilot study was to explore the attitudes and perceptions of members of the UK public towards self-care for minor ailments. Background: With an ageing and increasing population, and a National Health Service in extremis with plummeting performance indicators and the huge disparity between available funding and costs of treatments, methods to reduce demand upon health services are key. Increasing the use of self-care for minor ailments is one way in which this pressure could be alleviated. Design + Method: This study utilised qualitative methods including semi-structured telephone interviews. This data was then valuated, and key themes are drawn out of the data using thematic analysis. Findings: The results showed that the public are aware of the notion of self-care, and some are engaging with it. However, for a number of reasons, patients are still likely to want a face to face appointment despite the use of internet and telephone advice services. Conclusion: The study highlighted that there are multifactorial aspects impacting upon a patient’s likelihood to engage in self-care when faced with a minor illness. The results are not generalisable to every member of the UK public, but interesting questions are raised with regards to the usefulness of current public health messages being portrayed across various media when there appears to be a lack of desire from the public to use some recommended services

A shortcut to identifying small molecule signals that regulate behavior and development in Caenorhabditis elegans

Small molecule metabolites play important roles in Caenorhabditis elegans biology, but effective approaches for identifying their chemical structures are lacking. Recent studies revealed that a family of glycosides, the ascarosides, differentially regulate C. elegans development and behavior. Low concentrations of ascarosides attract males and thus appear to be part of the C. elegans sex pheromone, whereas higher concentrations induce developmental arrest at the dauer stage, an alternative, nonaging larval stage. The ascarosides act synergistically, which presented challenges for their identification via traditional activity-guided fractionation. As a result the chemical characterization of the dauer and male attracting pheromones remained incomplete. Here, we describe the identification of several additional pheromone components by using a recently developed NMR-spectroscopic approach, differential analysis by 2D NMR spectroscopy (DANS), which simplifies linking small molecule metabolites with their biological function. DANS-based comparison of wild-type C. elegans and a signaling-deficient mutant, daf-22, enabled identification of 3 known and 4 previously undescribed ascarosides, including a compound that features a p-aminobenzoic acid subunit. Biological testing of synthetic samples of these compounds revealed additional evidence for synergy and provided insights into structure–activity relationships. Using a combination of the three most active ascarosides allowed full reconstitution of the male-attracting activity of wild-type pheromone extract. Our results highlight the efficacy of DANS as a method for identifying small-molecule metabolites and placing them within a specific genetic context. This study further supports the hypothesis that ascarosides represent a structurally diverse set of nematode signaling molecules regulating major life history traits