The influence of area level social deprivation on preoperative disease severity and postoperative outcomes following unicompartmental knee joint replacement

BACKGROUND: This study investigated the effect of socioeconomic deprivation on preoperative disease and outcome following unicompartmental knee replacement (UKR).

METHODS: 307 Oxford UKRs implanted between 2008 and 2013 under the care of one surgeon using the same surgical technique were analysed. Deprivation was quantified using the Northern Ireland Multiple Deprivation Measure. Preoperative disease severity and postoperative outcome were measured using the Oxford Knee Score (OKS).

RESULTS: There was no difference in preoperative OKS between deprivation groups. Preoperative knee range of motion (ROM) was significantly reduced in more deprived patients with 10° less ROM than least deprived patients. Postoperatively there was no difference in OKS improvement between deprivation groups (p=0.46), with improvements of 19.5 and 21.0 units in the most and least deprived groups respectively. There was no significant association between deprivation and OKS improvement on unadjusted or adjusted analysis. Preoperative OKS, Short Form 12 mental component score and length of stay were significant independent predictors of OKS improvement. A significantly lower proportion of the most deprived group (15%) reported being able to walk an unlimited distance compared to the least deprived group (41%) one year postoperatively.

CONCLUSION: More deprived patients can achieve similar improvements in OKS to less deprived patients following UKR.

LEVEL OF EVIDENCE: 2b - retrospective cohort study of prognosis.

Spatio-temporal Rich Model Based Video Steganalysis on Cross Sections of Motion Vector Planes

A rich model based motion vector steganalysis benefiting from both temporal and spatial correlations of motion vectors is proposed in this work. The proposed steganalysis method has a substantially superior detection accuracy than the previous methods, even the targeted ones. The improvement in detection accuracy lies in several novel approaches introduced in this work. Firstly, it is shown that there is a strong correlation, not only spatially but also temporally, among neighbouring motion vectors for longer distances. Therefore, temporal motion vector dependency along side the spatial dependency is utilized for rigorous motion vector steganalysis. Secondly, unlike the filters previously used, which were heuristically designed against a specific motion vector steganography, a diverse set of many filters which can capture aberrations introduced by various motion vector steganography methods is used. The variety and also the number of the filter kernels are substantially more than that of used in previous ones. Besides that, filters up to fifth order are employed whereas the previous methods use at most second order filters. As a result of these, the proposed system captures various decorrelations in a wide spatio-temporal range and provides a better cover model. The proposed method is tested against the most prominent motion vector steganalysis and steganography methods. To the best knowledge of the authors, the experiments section has the most comprehensive tests in motion vector steganalysis field including five stego and seven steganalysis methods. Test results show that the proposed method yields around 20% detection accuracy increase in low payloads and 5% in higher payloads.

The diversity of extradiol dioxygenase (edo) genes in cresol degrading rhodococci from a creosote-contaminated site that express a wide range of degradative abilities.

Analysis of the bacterial population of soil surface samples from a creosote-contaminated site showed that up to 50% of the culturable micro-organisms detected were able to utilise a mixture of cresols. From fifty different microbial isolates fourteen that could utilise more than one cresol isomer were selected and identified by 16S rRNA analysis. Eight isolates were Rhodococcus strains and six were Pseudomonas strains. In general, the Rhodococcus strains exhibited a broader growth substrate range than the Pseudomonas strains. The distribution of various extradiol dioxygenase (edo) genes, previously associated with aromatic compound degradation in rhodococci, was determined for the Rhodococcus strains by PCR detection and Southern-blot hybridization. One strain, Rhodococcus sp. I1 exhibited the broadest growth substrate range and possessed five different edo genes. Gene disruption experiments indicated that two genes (edoC and edoD) were associated with isopropylbenzene and naphthalene catabolism respectively. The other Rhodococcus strains also possessed some of the edo genes and one (edoB) was present in all of the Rhodococcus strains analysed. None of the rhodococcal edo genes analysed were present in the Pseudomonas strains isolated from the site. It was concluded that individual strains of Rhodococcus possess a wide degradative ability and may be very important in the degradation of complex mixtures of substrates found in creosote.

Production and characterisation of polyclonal antibodies to a range of nitroimidazoles.

The nitroimidazoles dimetridazole and ronidazole are metabolised to hydroxydimetridazole, while metronidazole is metabolised to hydroxymetronidazole. To screen for a large number of samples by immunoassay for the presence of this family of drugs and metabolites, it was necessary to produce an antibody with broad-spectrum recognition. Metronidazole and hydroxydimetridazole were selected as antigens as they could be coupled to large (immunogenic) carrier proteins at two different positions of the general nitroimidazole structure. The resulting conjugates were used to immunise rabbits, sheep and goats. Seventeen out of thirty-nine animals immunised produced a detectable antibody titre and these antibodies were consequently characterised as regards sensitivity and cross-reactivity.

The panel of antisera produced exhibited IC50 ranging from 1.26 to 73.76 ng ml-1 using a competitive ELISA assay. Cross-reactivity studies showed that sera from several animals were capable of significant binding of six of the seven nitroimidazole compounds tested.

The visual processing of motion-defined transparency

Our understanding of how the visual system processes motion transparency, the phenomenon by which multiple directions of motion are perceived to co-exist in the same spatial region, has grown considerably in the past decade. There is compelling evidence that the process is driven by global-motion mechanisms. Consequently, although transparently moving surfaces are readily segmented over an extended space, the visual system cannot separate two motion signals that co-exist in the same local region. A related issue is whether the visual system can detect transparently moving surfaces simultaneously, or whether the component signals encounter a serial â??bottleneckâ?? during their processing? Our initial results show that, at sufficiently short stimulus durations, observers cannot accurately detect two superimposed directions; yet they have no difficulty in detecting one pattern direction in noise, supporting the serial-bottleneck scenario. However, in a second experiment, the difference in performance between the two tasks disappears when the component patterns are segregated. This discrepancy between the processing of transparent and non-overlapping patterns may be a consequence of suppressed activity of global-motion mechanisms when the transparent surfaces are presented in the same depth plane. To test this explanation, we repeated our initial experiment while separating the motion components in depth. The marked improvement in performance leads us to conclude that transparent motion signals are represented simultaneously.

A comparison of a range of models for dispersion in a partially stratified room

A comparative study of models used to predict contaminant dispersion in a partially stratified room is presented. The experiments were carried out in a ventilated test room, with an initially evenly dispersed pollutant. Air was extracted from the outlet in the ceiling of the room at 1 and 3 air changes per hour. A small temperature difference between the top and bottom of the room causes very low air velocities, and higher concentrations, in the lower half of the room. Grid-independent CFD calculations were compared with predictions from a zonal model and from CFD using a very coarse grid. All the calculations show broadly similar contaminant concentration decay rates for the three locations monitored in the experiments, with the zonal model performing surprisingly well. For the lower air change rate, the models predict a less well mixed contaminant distribution than the experimental measurements suggest. With run times of less than a few minutes, the zonal model is around two orders of magnitude faster than coarse-grid CFD and could therefore be used more easily in parametric studies and sensitivity analyses. For a more detailed picture of internal dispersion, a CFD study using coarse and standard grids may be more appropriate.

Extension of the Ye and Shreeve group contribution method for density estimation of ionic liquids in a wide range of temperatures and pressures

An extension of the Ye and Shreeve group contribution method [C. Ye, J.M. Shreeve, J. Phys. Chem. A 111 (2007) 1456–1461] for the estimation of densities of ionic liquids (ILs) is here proposed. The new version here presented allows the estimation of densities of ionic liquids in wide ranges of temperature and pressure using the previously proposed parameter table. Coefficients of new density correlation proposed were estimated using experimental densities of nine imidazolium-based ionic liquids. The new density correlation was tested against experimental densities available in literature for ionic liquids based on imidazolium, pyridinium, pyrrolidinium and phosphonium cations. Predicted densities are in good agreement with experimental literature data in a wide range of temperatures (273.15–393.15 K) and pressures (0.10–100 MPa). For imidazolium-based ILs, the mean percent deviation (MPD) is 0.45% and 1.49% for phosphonium-based ILs. A low MPD ranging from 0.41% to 1.57% was also observed for pyridinium and pyrrolidinium-based ILs.

The effect of co-precipitation on cadmium(II) adsorption on hydrous aluminium(III) hydroxide in the presence of a range of chelates

The adsorption of cadmium(II) on freshly precipitated aluminium(III) hydroxide in the presence of a range of chelates has been investigated. By precipitating the metal, chelate and adsorbent together it is possible to change the pH variation of the metal-complex adsorption from anionic, ligand-like, binding to cationic binding. This is a general phenomenon and is explained by the formation of a ternary Al-O-Cd-L surface species. As a consequence of the preparation method, the pH edge is found to shift to lower pH values in the presence of the chelate which gives rise to an apparent increase in adsorption of Cd2+. This increase is, in general, most pronounced at [chelate] / [metal] > 1. Computer modelling shows that the observed trends result from the competition between Al-O-Cd-L and Al-L for the available aluminium( III) binding sites. The enhanced adsorption in the presence of phenylenediaminetetraacetate is anomalous since it is observed at a [ chelate] / [metal] approximate to 0.1 and cannot be interpreted by the simple competition model.

The role played by a range of psychological variables in nurses’ handwashing behaviour

Background: Psychological models of behaviour change are used to predict patients’ health behaviours but have rarely been used to explore healthcare professionals’ health-related behaviour. Aim: To explore the association between self-reported handwashing and a range of psychological variables in a sample of nurses in a large acute hospital. Results and discussion: Nurses in this study were more likely to wash their hands if they perceived it to be important and if they thought their workplace helped them in doing so. The best predictor of perceived importance was how strongly a nurse believed that poor handwashing practice contributes to spreading infection. Conclusion: In this study, psychological variables such as perception of importance, perception of workplace support, occupational stress and perception of risk were important predictors of handwashing behaviour.

Antimicrobial activity of neuropeptides against a range of micro-organisms from skin, oral, respiratory and gastrointestinal tract sites

Many neuropeptides are similar in size, amino acid composition and charge to antimicrobial peptides. This study aimed to determine whether the neuropeptides substance P (SP), neurokinin A (NKA), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), displayed antimicrobial activity against Streptococcus mutans, Lactobacillus acidophilus, Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. SP, NPY, VIP and CGRP displayed variable degrees of antimicrobial activity against all the pathogens tested with the exception of S. aureus. These antimicrobial activities add a further dimension to the immunomodulatory roles for neuropeptides in the inflammatory and immune responses. (c) 2008 Elsevier B.V. All rights reserved.

Pleistocene glaciation events shape genetic structure across the range of the American lobster, Homarus americanus

A north/south discontinuity along the northeastern coast of North America in the genetic structure of the American lobster (Homarus americanus) was detected using a suite of 13 microsatellite loci assessed using spatial analyses. Population genetic data laid over existing data on physiographic changes and sea-surface temperatures were used to reconstruct the Pleistocene distribution of this species. A postglacial northern-edge colonization model best explains the relative genetic homogeneity of the northern region compared to the southern region centred in the Gulf of Maine. Population genetic analyses identified significant structure (range of standardized theta 0-0.02) but no significant evidence for isolation by distance. The novel application of spatial genetic analyses to a marine species allowed us to interpret these results by providing a greater insight into the evolutionary factors responsible for shaping the genetic structure of this species throughout is natural range.