436 research outputs found

    Transcriptome profiling reveals expression signatures of cranial neural crest cells arising from different axial levels

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    Background: Cranial neural crest cells (NCCs) are a unique embryonic cell type which give rise to a diverse array of derivatives extending from neurons and glia through to bone and cartilage. Depending on their point of origin along the antero-posterior axis cranial NCCs are rapidly sorted into distinct migratory streams that give rise to axial specific structures. These migratory streams mirror the underlying segmentation of the brain with NCCs exiting the diencephalon and midbrain following distinct paths compared to those exiting the hindbrain rhombomeres (r). The genetic landscape of cranial NCCs arising at different axial levels remains unknown. Results: Here we have used RNA sequencing to uncover the transcriptional profiles of mouse cranial NCCs arising at different axial levels. Whole transcriptome analysis identified over 120 transcripts differentially expressed between NCCs arising anterior to r3 (referred to as r1-r2 migratory stream for simplicity) and the r4 migratory stream. Eight of the genes differentially expressed between these populations were validated by RT-PCR with 2 being further validated by in situ hybridisation. We also explored the expression of the Neuropilins (Nrp1 and Nrp2) and their co-receptors and show that the A-type Plexins are differentially expressed in different cranial NCC streams. Conclusions: Our analyses identify a large number of genes differentially regulated between cranial NCCs arising at different axial levels. This data provides a comprehensive description of the genetic landscape driving diversity of distinct cranial NCC streams and provides novel insight into the regulatory networks controlling the formation of specific skeletal elements and the mechanisms promoting migration along different paths.Rachael Lumb, Sam Buckberry, Genevieve Secker, David Lawrence and Quenten Schwar

    On the hierarchical classification of G Protein-Coupled Receptors

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    Motivation: G protein-coupled receptors (GPCRs) play an important role in many physiological systems by transducing an extracellular signal into an intracellular response. Over 50% of all marketed drugs are targeted towards a GPCR. There is considerable interest in developing an algorithm that could effectively predict the function of a GPCR from its primary sequence. Such an algorithm is useful not only in identifying novel GPCR sequences but in characterizing the interrelationships between known GPCRs. Results: An alignment-free approach to GPCR classification has been developed using techniques drawn from data mining and proteochemometrics. A dataset of over 8000 sequences was constructed to train the algorithm. This represents one of the largest GPCR datasets currently available. A predictive algorithm was developed based upon the simplest reasonable numerical representation of the protein's physicochemical properties. A selective top-down approach was developed, which used a hierarchical classifier to assign sequences to subdivisions within the GPCR hierarchy. The predictive performance of the algorithm was assessed against several standard data mining classifiers and further validated against Support Vector Machine-based GPCR prediction servers. The selective top-down approach achieves significantly higher accuracy than standard data mining methods in almost all cases

    The role of primary healthcare professionals in oral cancer prevention and detection

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    AIM: To investigate current knowledge, examination habits and preventive practices of primary healthcare professionals in Scotland, with respect to oral cancer, and to determine any relevant training needs. SETTING: Primary care. METHOD: Questionnaires were sent to a random sample of 357 general medical practitioners (GMPs) and 331 dental practitioners throughout Scotland. Additionally, focus group research and interviews were conducted amongst primary healthcare team members. RESULTS: Whilst 58% of dental respondents reported examining regularly for signs of oral cancer, GMPs examined patients' mouths usually in response to a complaint of soreness. The majority of GMPs (85%) and dentists (63%) indicated that they felt less than confident in detecting oral cancer, with over 70% of GMPs identifying lack of training as an important barrier. Many practitioners were unclear concerning the relative importance of the presence of potentially malignant lesions in the oral cavity. A high proportion of the GMPs indicated that they should have a major role to play in oral cancer detection (66%) but many felt strongly that this should be primarily the remit of the dental team. CONCLUSION: The study revealed a need for continuing education programmes for primary care practitioners in oral cancer-related activities. This should aim to improve diagnostic skills and seek to increase practitioners' participation in preventive activities

    The Extraordinary `Superthin' Spiral Galaxy UGC7321. I. Disk Color Gradients and Global Properties from Multiwavelength Observations

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    We present B- and R-band imaging and photometry, H-alpha narrow-band imaging, NIR H-band imaging, and HI 21-cm spectroscopy of the nearby Sd spiral galaxy UGC7321. UGC7321 exhibits a remarkably thin stellar disk with no bulge component. The galaxy has a very diffuse, low surface brightness disk, which appears to suffer little internal extinction in spite of its edge-on geometry. The UGC7321 disk shows significant B-R color gradients in both the radial and vertical directions. These color gradients cannot be explained solely by dust and are indicative of changes in the mix of stellar ages and/or metallicity as a function of both radius and height above the galaxy plane. The outer regions of the UGC7321 disk are too blue to be explained by low metallicity alone (B-R<0.6), and must be relatively young. However, the galaxy also contains stellar populations with B-R>1.1, indicating it is not a young or recently-formed galaxy. The disk of UGC7321 is not a simple exponential, but exhibits a light excess at small radii, as well as distinct surface brightness zones. Together the properties of UGC7321 imply that it is an under-evolved galaxy in both a dynamical and in a star-formation sense. (Abridged)Comment: Accepted to the Astronomical Journal; 28 pages, 1 table and 21 figures (GIF and postscript

    Extragalactic Globular Clusters in the Near-Infrared: V. IC 4051 and NGC 3311

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    We present the results of combined optical and near-infrared photometry for the globular cluster systems of the giant ellipticals IC 4051 and NGC 3311. We use the reduced age-metallicity degeneracy in (V-I) vs.(V-H) color-color diagrams to derive the cumulative age distribution within the red sub-population of globular clusters and to search for age sub-populations. The age distribution is then compared to the one determined for simulated globular cluster systems in order to set constraints on the relative age and size of these globular cluster sub-populations. In both galaxies we find a significant fraction of globular clusters with ages between 2- 5 Gyr. We also investigate the metallicity distribution in both systems. Small number statistics prevent us from making any definite statements concerning NGC 3311, but we find that the derived metallicity distribution of the IC 4051 clusters strongly depends on the assumed age distribution. Based on our most likely result that finds a large number of young/intermediate age clusters (~2 Gyr) within the selected globular cluster sample, we find metallicity peaks at \sim -0.2 for the old clusters and +0.8 for the young clusters. Only few very metal poor clusters are found. However, the metallicity distribution within the young/intermediate globular cluster population is significantly affected by our choice of the applied Single Stellar Population model. The mean metallicity of the second generation of globular clusters changes from the above mentioned and extremely high +0.8 dex to +0.2 dex. Note that the model dependency becomes less severe with an increasing age of the cluster population.Comment: 21 pages, 21 figures, A&A, accepte

    Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902

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    We present a study of the population of bright early-type dwarf galaxies in the multiple-cluster system Abell 901/902. We use data from the STAGES survey and COMBO-17 to investigate the relation between the color and structural properties of the dwarfs and their location in the cluster. The definition of the dwarf sample is based on the central surface brightness and includes galaxies in the luminosity range -16 >= M_B >~-19 mag. Using a fit to the color magnitude relation of the dwarfs, our sample is divided into a red and blue subsample. We find a color-density relation in the projected radial distribution of the dwarf sample: at the same luminosity dwarfs with redder colors are located closer to the cluster centers than their bluer counterparts. Furthermore, the redder dwarfs are on average more compact and rounder than the bluer dwarfs. These findings are consistent with theoretical expectations assuming that bright early-type dwarfs are the remnants of transformed late-type disk galaxies involving processes such as ram pressure stripping and galaxy harassment. This indicates that a considerable fraction of dwarf elliptical galaxies in clusters are the results of transformation processes related to interactions with their host cluster.Comment: 12 pages, 8 figures, accepted for publication in A&A, typo corrected in abstrac

    Still dreaming: service users' employment, education & training goals

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    Background: Enabling service users to find and keep real jobs is a significant strand of UK mental health policy. An evidence-based approach to employment support is well documented, but is not widely implemented in the UK. Aim: To inform the development of vocational services in South Essex by ascertaining service users' employment, education and training goals. Method: Face-to-face interviews with a randomly selected sample of service users on enhanced CPA carried out by a team of service user researchers using an adapted version of a questionnaire developed for a previous similar survey. A postal survey of a further randomly selected sample of service users on enhanced CPA using a brief version of the questionnaire was also carried out. Results: Interviews were carried out with 82 service users. A further 159 returned a postal questionnaire. 42.7% had no regular day time activity. Only 15% were in paid work. 60.6% were definitely interested in finding work. Seventy-seven percent of respondents to the interviews who were interested in work were not currently receiving support to achieve this. The main help wanted was support in work, help with mental health problems and benefits advice. The main barriers identified were employers' attitudes and threat to benefits. Service user researchers reported benefits from undertaking the work. Conclusions: High numbers of mental health service users are interested in pursuing employment, education or training goals but currently lack the support they need to do so. Implementation of an evidence-based approach to employment support has the potential to enable service users to achieve their goals. Service users are well able to undertake research with considerable benefits for themselves and other stakeholders

    Panspermia, Past and Present: Astrophysical and Biophysical Conditions for the Dissemination of Life in Space

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    Astronomically, there are viable mechanisms for distributing organic material throughout the Milky Way. Biologically, the destructive effects of ultraviolet light and cosmic rays means that the majority of organisms arrive broken and dead on a new world. The likelihood of conventional forms of panspermia must therefore be considered low. However, the information content of dam-aged biological molecules might serve to seed new life (necropanspermia).Comment: Accepted for publication in Space Science Review
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