History of eating disorder in mothers of children with early onset eating disorder or disturbance

The literature suggests that there is significant familial aggregation of eating disorders. A specific association has also been reported between childhood feeding problems and maternal eating disorder. This study investigates whether subgroups of children with early onset eating disturbance are distinguished by maternal eating disorder history. The mothers of 66 children with either anorexia nervosa (AN), food avoidance emotional disorder (FAED) or selective eating (SE) were interviewed to ascertain eating disorder history. Seventeen per cent of mothers reported a history of eating disorder, compared with 3%–5% reported for community samples. A history of eating disorder was reported by 5.9% of mothers of children with SE, 12.9% of mothers of children with AN and 33.3% of mothers of children with FAED. The findings, based on this small sample, suggest that children with FAED are especially likely to have grown up in a dysfunctional food environment.

Cinnamate ester containing liquid crystalline side chain polymers

The synthesis of methacrylate esters of 4-cyanophenyl-(4-(ω-hydroxyalkyloxy)) cinnamates, with spacer lengths of 2 and 6 methylene units and the synthesis of the corresponding acrylate ester with a spacer of 2 methylene units are described. The methacrylate monomers were polymerized by free radical polymerization, both as homopolymers and as copolymers with the analogous benzoate monomer of spacer length 6. The acrylate ester could not be polymerized successfully under the same reaction conditions. Polymers were characterized by NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, and thermo-optic observations. Of the monomers prepared, only the cinnamate with a hexamethylene spacer shows a mesophase, seen on supercooling of the melt. All of the polymers prepared were liquid crystalline, with smectic behavior predominating in the polymethacrylates with the longer spacer group. A narrow nematic region is seen just below the clearing temperature with a range of 3–9°C, nematic character is increased in the copolymer series with the degree of incorporation of the cinnamate monomer with the spacer group of length 2.

Synthesis and evaluation of lipophilic BTBP ligands for An/Ln separation in nuclear waste treatment: the effect of alkyl substitution on extraction properties and implications for ligand design

Four new 6,6′-bis(1,2,4-triazin-3-yl)-2,2′-bipyridine (BTBP) ligands, which contain either additional alkyl groups on the pyridine rings or seven-membered aliphatic rings attached to the triazine rings, have been synthesized, and the effects of the additional alkyl substitution in the 4- and 4′-positions of the pyridine rings on their extraction properties with LnIII and AnIII cations in simulated nuclear waste solutions have been studied. The speciation of ligand 13 with some trivalent lanthanide nitrates was elucidated by 1H NMR spectroscopic titrations and ESI-MS. Although 13 formed both 1:1 and 1:2 complexes with LaIII and YIII, only 1:2 complexes were observed with EuIII and CeIII. Quite unexpectedly, both alkyl-substituted ligands 12 and 13 showed lower solubilities in certain diluents than the unsubstituted ligand CyMe4-BTBP. Compared to CyMe4-BTBP, alkyl-substitution was found to decrease the rates of metal-ion extraction of the ligands in both 1-octanol and cyclohexanone. A highly efficient (DAm > 10) and selective (SFAm/Eu > 90) extraction was observed for 12 and 13 in cyclohexanone and for 13 in 1-octanol in the presence of a phase-transfer agent. The implications of these results for the design of improved extractants for radioactive waste treatment are discussed.

Towards the total synthesis of mycaperoxide B: probing biosynthetic rationale

Studies towards the biomimetic synthesis of mycaperoxide B (1) are described. We have established the synthesis of four diastereoisomers of mycaperoxide B methyl ester (1a) by employing a Michael addition across an α,β-unsaturated ester precursor 2 as the key step. This result strongly suggestsstereocontrol in the addition of the hydroperoxide functionality to the E double bond and discloses the importance of choosing the correct geometry of the α,β-unsaturated double bond when attempting to synthesise mycaperoxide B. Four diastereoisomeric tetrahydrofurans derived from an intramolecular rearrangement of the 1,2-dioxolane enolate 12 were also isolated and characterised.

Galleria mellonella as an infection model for Campylobacter jejuni virulence

Larvae of Galleria mellonella (Greater Wax Moth) have been shown to be susceptible to Campylobacter jejuni infection and our study characterizes this infection model. Following infection with C. jejuni human isolates, bacteria were visible in the haemocoel and gut of challenged larvae, and there was extensive damage to the gut. Bacteria were found in the extracellular and cell-associated fraction in the haemocoel, and it was shown that C. jejuni can survive in insect cells. Finally, we have used the model to screen a further 67 C. jejuni isolates belonging to different MLST types. Isolates belonging to ST257 were the most virulent in the Galleria model, whereas those belonging to ST21 were the least virulent.

Purified galactooligosaccharide, derived from a mixture produced by the enzymic activity of Bifidobacterium bifidum, reduces Salmonella enterica serovar Typhimurium adhesion and invasion in vitro and in vivo

The prebiotic Bimuno (R) is a mixture containing galactooligosaccharides (GOSs), produced by the galactosyltransferase activity of Bifidobacterium bifidum NCIMB 411 71 using lactose as the substrate Previous in vivo and in vitro studies demonstrating the efficacy of Bimuno (R) in reducing Salmonella enterica serovar Typhimurium (S Typhimurium) colonization did not ascertain whether or not the protective effects could be attributed to the prebiotic component GOS Here we wished to test the hypothesis that GOS, derived from Bimuno (R) may confer the direct anti-invasive and protective effects of Bimuno (R) In this study the efficacy of Bimuno (R), a basal solution of Bimuno (R) without GOS [which contained glucose, galactose, lactose, maltodextrin and gum arabic in the same relative proportions (w/w) as they are found in Bimuno (R)] and purified GOS to reduce S Typhimurium adhesion and invasion was assessed using a series of in vitro and in vivo models The novel use of three dimensionally cultured HT-29-16E cells to study prebiotics in vitro demonstrated that the presence of similar to 5 mg Bimuno (R) ml(-1) or similar to 2 5 mg GOS ml(-1) significantly reduced the invasion of S Typhimurium (SL1344nal(r)) (P<0 0001) Furthermore, similar to 2 5 mg GOS ml(-1) significantly reduced the adherence of S Typhimurium (SU 344nal(r)) (P<0 0001) It was demonstrated that cells produced using this system formed multi-layered aggregates of cells that displayed excellent formation of brush borders and tight junctions In the murine ligated deal gut loops, the presence of Bimuno (R) or GOS prevented the adherence or invasion of S Typhimurium to enterocytes, and thus reduced its associated pathology This protection appeared to correlate with significant reductions in the neutral and acidic mucins detected in goblet cells, possibly as a consequence of stimulating the cells to secrete the mucin into the lumen In all assays, Bimuno (R) without GOS conferred no such protection, indicating that the basal solution confers no protective effects against S Typhimurium Collectively, the studies presented here clearly indicate that the protective effects conferred by Bimuno (R) can be attributed to GOS

A mixture containing galactoollgosaccharide, produced by the enzymic activity of Bifidobacterium bifidum, reduces Salmonella enterica serovar Typhimurium infection in mice

The prebiotic Bimuno (R) is a mixture containing galactooligosaccharide, produced by the galactosyltransferase activity of Bifidobacterium bifidum NCIMB 41 .vertical bar 71 in the presence of lactose. Previous studies have implicated prebiotics in reducing infections by enteric pathogens, thus it was hypothesized that Bimuno (R) may confer some protection in the murine host from Salmonella enterica serovar Typhimurium (S. Typhimurium) infection. In this study, infection caused by S. Typhimurium SL1344nal(r) in the presence or absence of Bimuno (R) was assessed using tissue culture assays, a murine ligated ileal gut loop model and a murine oral challenge model. In tissue culture adherence and invasion assays with HT-29-1 6E cells, the presence of similar to 2 mM Bimuno) significantly reduced the invasion of S. Typhimuriurn SL1 344nal(r) (p < 0.0001). In the murine ligated ileal gut loops, the presence of Bimuno (R) prevented colonization and the associated pathology of S. Typhimurium. In the BALB/c mouse mocel, the oral delivery of Bimuno prior to challenge with S. Typhimurium resulted in significant reductions in colonization in the five organs sampled, with highly significant reductions being observed in the spleen at 72 and 96 h post-challenge (P=0.0002, < 0.0001, respectively). Collectively, the results indicate that Bimuno (R) significantly reduced the colonization and pathology associated with S. Typhimurium infection in a murine model system, possibly by reducing the invasion of the pathogen into host cells.

Identification of genetic and phenotypic differences associated with prevalent and non-prevalent Salmonella Enteritidis phage types: analysis of variation in amino acid transport

In this study, differences at the genetic level of 37 Salmonella Enteritidis strains from five phage types (PTs) were compared using comparative genomic hybridization (CGH) to assess differences between PTs. There were approximately 400 genes that differentiated prevalent (4, 6, 8 and 13a) and sporadic (11) PTs, of which 35 were unique to prevalent PTs, including six plasmid-borne genes, pefA, B, C, D, srgC and rck, and four chromosomal genes encoding putative amino acid transporters. Phenotype array studies also demonstrated that strains from prevalent PTs were less susceptible to urea stress and utilized L-histidine, L-glutamine, L-proline, L-aspartic acid, gly-asn and gly-gln more efficiently than PT11 strains. Complementation of a PT11 strain with the transporter genes from PT4 resulted in a significant increase in utilization of the amino acids and reduced susceptibility to urea stress. In epithelial cell association assays, PT11 strains were less invasive than other prevalent PTs. Most strains from prevalent PTs were better biofilm formers at 37 degrees C than at 28 degrees C, whilst the converse was true for PT11 strains. Collectively, the results indicate that genetic and corresponding phenotypic differences exist between strains of the prevalent PTs 4, 6, 8 and 13a and non-prevalent PT11 strains that are likely to provide a selective advantage for strains from the former PTs and could help them to enter the food chain and cause salmonellosis.

Contribution of N Species and P Fractions to Stream Water Quality in Agricultural Catchments

The contribution from agricultural catchments to stream nitrogen and phosphorus concentrations was assessed by evaluation of the chemical composition of these nutrients in agricultural runoff for both surface and subsurface flow pathways. A range of land uses (grazed and ungrazed grassland, cereals, roots) in intensive agricultural systems was studied at scales from hillslope plots (0.5m2) to large catchment (>300km2). By fractionating the total nutrient load it was possible to establish that most of the phosphorus was transported in the unreactive (particulate and organic) fraction via surface runoff. This was true regardless of the scale of measurement. The form of the nitrogen load varied with land use and grazing intensity. High loads of dissolved inorganic nitrogen (with >90% transported as NH4-N) were recorded in surface runoff from heavily grazed land. In subsurface flow from small (2km2) subcatchments and in larger (>300 km2) catchments, organic nitrogen was found to be an important secondary constituent of the total nitrogen load, comprising 40% of the total annual load.

Trends in nutrients

The roles of nitrogen (N) and phosphorus (P) as key nutrients determining the trophic status of water bodies are examined, and evidence reviewed for trends in concentrations of N and P species which occur in freshwaters, primarily in northern temperate environments. Data are reported for water bodies undergoing eutrophication and acidification, especially water bodies receiving increased nitrogen inputs through the atmospheric deposition of nitrogen oxides (NOx). Nutrient loading on groundwaters and surface freshwaters is assessed with respect to causes and rates of change, relative rates of change for N and P, and implications of change for the future management of lakes, rivers and groundwaters. In particular, the nature and emphasis of studies for N species and P fractions in lakes versus rivers and groundwaters are contrasted. This review paper primarily focuses on results from North America and Europe, particularly for the UK where a wide range of data sets exists. Few nutrient loading data have been published on water bodies in less developed countries; however, some of the available data are presented to provide a global perspective. In general, N and P concentrations have increased dramatically (>20 times background concentrations) in many areas and causes vary considerably, ranging from urbanization to changes in agricultural practices.

Modelling the impact of land use change on water quality in agricultural catchments

Export coefficient modelling was used to model the impact of agriculture on nitrogen and phosphorus loading on the surface waters of two contrasting agricultural catchments. The model was originally developed for the Windrush catchment where the highly reactive Jurassic limestone aquifer underlying the catchment is well connected to the surface drainage network, allowing the system to be modelled using uniform export coefficients for each nutrient source in the catchment, regardless of proximity to the surface drainage network. In the Slapton catchment, the hydrological path-ways are dominated by surface and lateral shallow subsurface flow, requiring modification of the export coefficient model to incorporate a distance-decay component in the export coefficients. The modified model was calibrated against observed total nitrogen and total phosphorus loads delivered to Slapton Ley from inflowing streams in its catchment. Sensitivity analysis was conducted to isolate the key controls on nutrient export in the modified model. The model was validated against long-term records of water quality, and was found to be accurate in its predictions and sensitive to both temporal and spatial changes in agricultural practice in the catchment. The model was then used to forecast the potential reduction in nutrient loading on Slapton Ley associated with a range of catchment management strategies. The best practicable environmental option (BPEO) was found to be spatial redistribution of high nutrient export risk sources to areas of the catchment with the greatest intrinsic nutrient retention capacity.

Steering without Circe : attending to reinforcing loops in social systems

Relating system dynamics to the broad systems movement, the key notion is that reinforcing loops deserve no less attention than balancing loops. Three specific propositions follow. First, since reinforcing loops arise in surprising places, investigations of complex systems must consider their possible existence and potential impact. Second, because the strength of reinforcing loops can be misinferred - we include an example from the field of servomechanisms - computer simulation can be essential. Be it project management, corporate growth or inventory oscillation, simulation helps to assess consequences of reinforcing loops and options for interventions. Third, in social systems the consequences of reinforcing loops are not inevitable. Examples concerning globalization illustrate how difficult it might be to challenge such assumptions. However, system dynamics and ideas from contemporary social theory help to show that even the most complex social systems are, in principle, subject to human influence. In conclusion, by employing these ideas, by attending to reinforcing as well as balancing loops, system dynamics work can improve the understanding of social systems and illuminate our choices when attempting to steer them.

Formal theory building for the avalanche game: explaining counter-intuitive behaviour of a complex system using geometrical and human behavioural/physiological effects

In 'Avalanche', an object is lowered, players staying in contact throughout. Normally the task is easily accomplished. However, with larger groups counter-intuitive behaviours appear. The paper proposes a formal theory for the underlying causal mechanisms. The aim is to not only provide an explicit, testable hypothesis for the source of the observed modes of behaviour-but also to exemplify the contribution that formal theory building can make to understanding complex social phenomena. Mapping reveals the importance of geometry to the Avalanche game; each player has a pair of balancing loops, one involved in lowering the object, the other ensuring contact. For more players, sets of balancing loops interact and these can allow dominance by reinforcing loops, causing the system to chase upwards towards an ever-increasing goal. However, a series of other effects concerning human physiology and behaviour (HPB) is posited as playing a role. The hypothesis is therefore rigorously tested using simulation. For simplicity a 'One Degree of Freedom' case is examined, allowing all of the effects to be included whilst rendering the analysis more transparent. Formulation and experimentation with the model gives insight into the behaviours. Multi-dimensional rate/level analysis indicates that there is only a narrow region in which the system is able to move downwards. Model runs reproduce the single 'desired' mode of behaviour and all three of the observed 'problematic' ones. Sensitivity analysis gives further insight into the system's modes and their causes. Behaviour is seen to arise only when the geometric effects apply (number of players greater than degrees of freedom of object) in combination with a range of HPB effects. An analogy exists between the co-operative behaviour required here and various examples: conflicting strategic objectives in organizations; Prisoners' Dilemma and integrated bargaining situations. Additionally, the game may be relatable in more direct algebraic terms to situations involving companies in which the resulting behaviours are mediated by market regulations. Finally, comment is offered on the inadequacy of some forms of theory building and the case is made for formal theory building involving the use of models, analysis and plausible explanations to create deep understanding of social phenomena.

Theory building with system dynamics: topic and research contributions

The article discusses various reports published within the issue, including the articles "Closing the Loop: Promoting Synergies with other Theory Building Approaches to Improve System Dynamics Practice," by Birgit Kopainsky and Luis Luna-Reyes, and "On improving dynamic decision-making: Implications from multiple-process cognitive theory," by Bent Bakken.