Collagen-hyaluronic acid scaffolds for adipose tissue engineering.

Three-dimensional (3-D) in vitro models of the mammary gland require a scaffold matrix that supports the development of adipose stroma within a robust freely permeable matrix. 3-D porous collagen-hyaluronic acid (HA: 7.5% and 15%) scaffolds were produced by controlled freeze-drying technique and crosslinking with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride. All scaffolds displayed uniform, interconnected pore structure (total porosity approximately 85%). Physical and chemical analysis showed no signs of collagen denaturation during the formation process. The values of thermal characteristics indicated that crosslinking occurred and that its efficiency was enhanced by the presence of HA. Although the crosslinking reduced the swelling of the strut material in water, the collagen-HA matrix as a whole tended to swell more and show higher dissolution resistance than pure collagen samples. The compressive modulus and elastic collapse stress were higher for collagen-HA composites. All the scaffolds were shown to support the proliferation and differentiation 3T3-L1 preadipocytes while collagen-HA samples maintained a significantly increased proportion of cycling cells (Ki-67+). Furthermore, collagen-HA composites displayed significantly raised Adipsin gene expression with adipogenic culture supplementation for 8 days vs. control conditions. These results indicate that collagen-HA scaffolds may offer robust, freely permeable 3-D matrices that enhance mammary stromal tissue development in vitro.This was supported by the Biotechnology and Biological Sciences Research Council

GPAQ-R: development and psychometric properties of a version of the general practice assessment questionnaire for use for revalidation by general practitioners in the UK.

BACKGROUND: The General Practice Assessment Questionnaire (GPAQ) has been widely used to assess patient experience in general practice in the UK since 2004. In 2013, new regulations were introduced by the General Medical Council (GMC) requiring UK doctors to undertake periodic revalidation, which includes assessment of patient experience for individual doctors. We describe the development of a new version of GPAQ - GPAQ-R which addresses the GMC's requirements for revalidation as well as additional NHS requirements for surveys that GPs may need to carry out in their own practices. METHODS: Questionnaires were given out by doctors or practice staff after routine consultations in line with the guidance given by the General Medical Council for surveys to be used for revalidation. Data analysis and practice reports were provided independently. RESULTS: Data were analysed for questionnaires from 7258 patients relating to 164 GPs in 29 general practices. Levels of missing data were generally low (typically 4.5-6%). The number of returned questionnaires required to achieve reliability of 0.7 were around 35 for individual doctor communication items and 29 for a composite score based on doctor communication items. This suggests that the responses to GPAQ-R had similar reliability to the GMC's own questionnaire and we recommend 30 completed GPAQ-R questionnaires are sufficient for revalidation purposes. However, where an initial screen raises concern, the survey might be repeated with 50 completed questionnaires in order to increase reliability. CONCLUSIONS: GPAQ-R is a development of a well-established patient experience questionnaire used in general practice in the UK since 2004. This new version can be recommended for use in order to meet the UK General Medical Council's requirements for surveys to be used in revalidation of doctors. It also meets the needs of GPs to ask about patient experience relating to aspects of practice care that are not specific to individual general practitioners (e.g. receptionists, telephone access) which meet other survey requirements of the National Health Service in England. Use of GPAQ-R has the potential to reduce the number of surveys that GPs need to carry out in their practices to meet the various regulatory requirements which they face

An adaptive technique for content-based image retrieval

We discuss an adaptive approach towards Content-Based Image Retrieval. It is based on the Ostensive Model of developing information needs—a special kind of relevance feedback model that learns from implicit user feedback and adds a temporal notion to relevance. The ostensive approach supports content-assisted browsing through visualising the interaction by adding user-selected images to a browsing path, which ends with a set of system recommendations. The suggestions are based on an adaptive query learning scheme, in which the query is learnt from previously selected images. Our approach is an adaptation of the original Ostensive Model based on textual features only, to include content-based features to characterise images. In the proposed scheme textual and colour features are combined using the Dempster-Shafer theory of evidence combination. Results from a user-centred, work-task oriented evaluation show that the ostensive interface is preferred over a traditional interface with manual query facilities. This is due to its ability to adapt to the user's need, its intuitiveness and the fluid way in which it operates. Studying and comparing the nature of the underlying information need, it emerges that our approach elicits changes in the user's need based on the interaction, and is successful in adapting the retrieval to match the changes. In addition, a preliminary study of the retrieval performance of the ostensive relevance feedback scheme shows that it can outperform a standard relevance feedback strategy in terms of image recall in category search

Effect of abdominal binding on respiratory mechanics during exercise in athletes with cervical spinal cord injury

West CR, Goosey-Tolfrey VL, Campbell IG, Romer LM. Effect of abdominal binding on respiratory mechanics during exercise in athletes with cervical spinal cord injury. J Appl Physiol 117: 36–45, 2014. First published May 22, 2014; doi:10.1152/japplphysiol.00218.2014.—We asked whether elastic binding of the abdomen influences respiratory mechanics during wheelchair propulsion in athletes with cervical spinal cord injury (SCI). Eight Paralympic wheelchair rugby players with motor-complete SCI (C5-C7) performed submaximal and maximal incremental exercise tests on a treadmill, both with and without abdominal binding. Measurements included pulmonary function, pressure-derived indices of respiratory mechanics, operating lung volumes, tidal flow-volume data, gas exchange, blood lactate, and symptoms. Residual volume and functional residual capacity were reduced with binding (77 18 and 81 11% of unbound, P 0.05), vital capacity was increased (114 9%, P 0.05), whereas total lung capacity was relatively well preserved (99 5%). During exercise, binding introduced a passive increase in transdiaphragmatic pressure, due primarily to an increase in gastric pressure. Active pressures during inspiration were similar across conditions. A sudden, sustained rise in operating lung volumes was evident in the unbound condition, and these volumes were shifted downward with binding. Expiratory flow limitation did not occur in any subject and there was substantial reserve to increase flow and volume in both conditions. V ˙ O2 was elevated with binding during the final stages of exercise (8 –12%, P 0.05), whereas blood lactate concentration was reduced (16 –19%, P 0.05). V ˙ O2/heart rate slopes were less steep with binding (62 35 vs. 47 24 ml/beat, P 0.05). Ventilation, symptoms, and work rates were similar across conditions. The results suggest that abdominal binding shifts tidal breathing to lower lung volumes without influencing flow limitation, symptoms, or exercise tolerance. Changes in respiratory mechanics with binding may benefit O2 transport capacity by an improvement in central circulatory function.This article has been made available through the Brunel Open Access Publishing Fund

Automation of one-loop QCD corrections

We present the complete automation of the computation of one-loop QCD corrections, including UV renormalization, to an arbitrary scattering process in the Standard Model. This is achieved by embedding the OPP integrand reduction technique, as implemented in CutTools, into the MadGraph framework. By interfacing the tool so constructed, which we dub MadLoop, with MadFKS, the fully automatic computation of any infrared-safe observable at the next-to-leading order in QCD is attained. We demonstrate the flexibility and the reach of our method by calculating the production rates for a variety of processes at the 7 TeV LHC.Comment: 64 pages, 12 figures. Corrected the value of m_Z in table 1. In table 2, corrected the values of cross sections in a.4 and a.5 (previously computed with mu=mtop/2 rather than mu=mtop/4). In table 2, corrected the values of NLO cross sections in b.3, b.6, c.3, and e.7 (the symmetry factor for a few virtual channels was incorrect). In sect. A.4.3, the labeling of the four-momenta was incorrec

Statistical modeling of ground motion relations for seismic hazard analysis

We introduce a new approach for ground motion relations (GMR) in the probabilistic seismic hazard analysis (PSHA), being influenced by the extreme value theory of mathematical statistics. Therein, we understand a GMR as a random function. We derive mathematically the principle of area-equivalence; wherein two alternative GMRs have an equivalent influence on the hazard if these GMRs have equivalent area functions. This includes local biases. An interpretation of the difference between these GMRs (an actual and a modeled one) as a random component leads to a general overestimation of residual variance and hazard. Beside this, we discuss important aspects of classical approaches and discover discrepancies with the state of the art of stochastics and statistics (model selection and significance, test of distribution assumptions, extreme value statistics). We criticize especially the assumption of logarithmic normally distributed residuals of maxima like the peak ground acceleration (PGA). The natural distribution of its individual random component (equivalent to exp(epsilon_0) of Joyner and Boore 1993) is the generalized extreme value. We show by numerical researches that the actual distribution can be hidden and a wrong distribution assumption can influence the PSHA negatively as the negligence of area equivalence does. Finally, we suggest an estimation concept for GMRs of PSHA with a regression-free variance estimation of the individual random component. We demonstrate the advantages of event-specific GMRs by analyzing data sets from the PEER strong motion database and estimate event-specific GMRs. Therein, the majority of the best models base on an anisotropic point source approach. The residual variance of logarithmized PGA is significantly smaller than in previous models. We validate the estimations for the event with the largest sample by empirical area functions. etc

Vector boson pair production at the LHC

We present phenomenological results for vector boson pair production at the LHC, obtained using the parton-level next-to-leading order program MCFM. We include the implementation of a new process in the code, pp -> \gamma\gamma, and important updates to existing processes. We incorporate fragmentation contributions in order to allow for the experimental isolation of photons in \gamma\gamma, W\gamma, and Z\gamma production and also account for gluon-gluon initial state contributions for all relevant processes. We present results for a variety of phenomenological scenarios, at the current operating energy of \sqrt{s} = 7 TeV and for the ultimate machine goal, \sqrt{s} = 14 TeV. We investigate the impact of our predictions on several important distributions that enter into searches for new physics at the LHC.Comment: 35 pages, 14 figure

Epithelial cell shedding and barrier function: a matter of life and death at the small intestinal villus tip

The intestinal epithelium is a critical component of the gut barrier. Composed of a single layer of intestinal epithelial cells (IECs) held together by tight junctions, this delicate structure prevents the transfer of harmful microorganisms, antigens, and toxins from the gut lumen into the circulation. The equilibrium between the rate of apoptosis and shedding of senescent epithelial cells at the villus tip, and the generation of new cells in the crypt, is key to maintaining tissue homeostasis. However, in both localized and systemic inflammation, this balance may be disturbed as a result of pathological IEC shedding. Shedding of IECs from the epithelial monolayer may cause transient gaps or microerosions in the epithelial barrier, resulting in increased intestinal permeability. Although pathological IEC shedding has been observed in mouse models of inflammation and human intestinal conditions such as inflammatory bowel disease, understanding of the underlying mechanisms remains limited. This process may also be an important contributor to systemic and intestinal inflammatory diseases and gut barrier dysfunction in domestic animal species. This review aims to summarize current knowledge about intestinal epithelial cell shedding, its significance in gut barrier dysfunction and host-microbial interactions, and where research in this field is directed

A study of the perceived risks, benefits and barriers to the use of SDD in adult critical care units (the SuDDICU study)

Peer reviewedPublisher PD