2,510 research outputs found

    Predicting the outcome of renal transplantation

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    ObjectiveRenal transplantation has dramatically improved the survival rate of hemodialysis patients. However, with a growing proportion of marginal organs and improved immunosuppression, it is necessary to verify that the established allocation system, mostly based on human leukocyte antigen matching, still meets today's needs. The authors turn to machine-learning techniques to predict, from donor-recipient data, the estimated glomerular filtration rate (eGFR) of the recipient 1 year after transplantation.DesignThe patient's eGFR was predicted using donor-recipient characteristics available at the time of transplantation. Donors' data were obtained from Eurotransplant's database, while recipients' details were retrieved from Charite Campus Virchow-Klinikum's database. A total of 707 renal transplantations from cadaveric donors were included.MeasurementsTwo separate datasets were created, taking features with <10% missing values for one and <50% missing values for the other. Four established regressors were run on both datasets, with and without feature selection.ResultsThe authors obtained a Pearson correlation coefficient between predicted and real eGFR (COR) of 0.48. The best model for the dataset was a Gaussian support vector machine with recursive feature elimination on the more inclusive dataset. All results are available at http://transplant.molgen.mpg.de/.LimitationsFor now, missing values in the data must be predicted and filled in. The performance is not as high as hoped, but the dataset seems to be the main cause.ConclusionsPredicting the outcome is possible with the dataset at hand (COR=0.48). Valuable features include age and creatinine levels of the donor, as well as sex and weight of the recipient

    The influence of rifle carriage on the kinetics of human gait

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    The influence that rifle carriage has on human gait has received little attention in the published literature. Rifle carriage has two main effects, to add load to the anterior of the body and to restrict natural arm swing patterns. Kinetic data were collected from 15 male participants, with 10 trials in each of four experimental conditions. The conditions were: walking without a load (used as a control condition); carrying a lightweight rifle simulator, which restricted arm movements but applied no additional load; wearing a 4.4 kg diving belt, which allowed arms to move freely; carrying a weighted (4.4 kg) replica SA80 rifle. Walking speed was fixed at 1.5 m/s (+5%) and data were sampled at 400 Hz. Results showed that rifle carriage significantly alters the ground reaction forces produced during walking, the most important effects being an increase in the impact peak and mediolateral forces. This study suggests that these effects are due to the increased range of motion of the body’s centre of mass caused by the impeding of natural arm swing patterns. The subsequent effect on the potential development of injuries in rifle carriers is unknown

    Improving Reflection during Student Teaching with Technology

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    ​The process of tapping into the power of reflection is a difficult process for many student teachers to accomplish. Multiple factors hinder the process of reflection in novice teachers. Video recorded lessons provide a contextualized focus for reflection on specific pedagogical skills. This study conducted by an undergraduate student during the student internship demonstrates the value of utilized video recorded lesson to assist in the development of one student’s journey toward becoming a reflective practitioner through the use of video recorded teaching episodes

    Molecular Approaches to Sarcoma Therapy

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    Soft tissue sarcomas comprise a heterogeneous group of aggressive tumors that have a relatively poor prognosis. Although conventional therapeutic regimens can effectively cytoreduce the overall tumor mass, they fail to consistently achieve a curative outcome. Alternative gene-based approaches that counteract the underlying neoplastic process by eliminating the clonal aberrations that potentiate malignant behavior have been proposed. As compared to the accumulation of gene alterations associated with epithelial carcinomas, sarcomas are frequently characterized by the unique presence of a single chromosomal translocation in each histological subtype. Similar to the Philadelphia chromosome associated with CML, these clonal abnormalities result in the fusion of two independent unrelated genes to generate a unique chimeric protein that displays aberrant activity believed to initiate cellular transformation. Secondary gene mutations may provide an additional growth advantage that further contributes to malignant progression. The recent clinical success of the tyrosine kinase inhibitor, STI571, suggests that therapeutic approaches specifically directed against essential survival factors in sarcoma cells may be effective. This review summarizes published approaches targeting a specific molecular mechanism associated with sarcomagenesis. The strategy and significance of published translational studies in six distinct areas are presented. These include: (1) the disruption of chimeric transcription factor activity; (2) inhibition of growth stimulatory post-translational modifications; (3) restoration of tumor suppressor function; (4) interference with angiogenesis; (5) induction of apoptotic pathways; and (6) introduction of toxic gene products. The potential for improving outcomes in sarcoma patients and the conceptual obstacles to be overcome are discussed

    General practitioner experience and perception of Child and Adolescent Mental Health Services (CAMHS) care pathways: a multimethod research study

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    This is the final version of the article. Available from BMJ Publishing via the DOI in this recordOBJECTIVES: This is a pilot study with the objective of investigating general practitioner (GP) perceptions and experiences in the referral of mentally ill and behaviourally disturbed children and adolescents. DESIGN: Quantitative analyses on patient databases were used to ascertain the source of referrals into Child and Adolescent Mental Health Services (CAMHS) and identify the relative contribution from GP practices. Qualitative semistructured interviews were then used to explore challenges faced by GPs in referring to CAMHS. SETTING: GPs were chosen from the five localities that deliver CAMHS within the local Trust (Peterborough City, Fenland, Huntingdon, Cambridge City and South Cambridgeshire). PARTICIPANTS: For the quantitative portion, data involving 19 466 separate referrals were used. Seven GPs took part in the qualitative interviews. RESULTS: The likelihood of a referral from GPs being rejected by CAMHS was over three times higher compared to all other referral sources combined within the Cambridge and Peterborough NHS Foundation Trust. Interviews showed that detecting the signs and symptoms of mental illness in young people is a challenge for GPs. Communication with referral agencies varies and depends on individual relationships. GPs determine whether to refer on a mixture of the presenting conditions and their perceived likelihood of acceptance by CAMHS; the criteria for the latter were poorly understood by the interviewed GPs. CONCLUSIONS: There are longstanding structural weaknesses in the services for children and young people in general, reflected in poor multiagency cooperation at the primary care level. GP-friendly guidelines and standards are required that will aid in decision-making and help with understanding the referrals process. We look to managers of both commissioning and providing organisations, as well as future research, to drive forward the development of tools, protocols, and health service structures to help aid the recognition and treatment of mental illness in young people.This work was supported by the National Institute for Health Research Collaborations for Leadership in Applied Health Research and Care (CLAHRC), grant number RNAG-186

    EFFECTS OF HANDLE AND BLOCK CONFIGURATION ON SWIM START PERFORMANCE

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    The purpose of this study was to quantify differences in swimming track start performances using side handle and front handle grip techniques and using an inclined platform at the rear of the starting platform. An instrumented starting block system was designed to allow front grip and side grip starting techniques and inclusion of a rear incline. Thirty male and 20 female junior elite swimmers completed three starts in each of four start block configurations: (1) Flat (traditional) block, front handle grip; (2) Flat (traditional) block, side handle grip; (3) Incline (new) block, front handle grip; (4) Incline (new) block, side handle grip. Force and video data were used to quantify parameters related to starting performance. Results indicated that use of side handles had a substantial impact on start performance while the effects of the rear incline were less pronounced. Compared to using a front grip technique, use of the side handles increased horizontal velocity at takeoff up to 18%, resulted in a more horizontal takeoff angle by up to 2°, increased contribution to horizontal impulse from arms up to 12%, increased peak horizontal power up to 28%, decreased time to 6 m by 4% and increased velocity at 6 m by 2.5%. These advantages were achieved at a cost of an 8% increase in propulsion time. Based on this study, we recommend swimmers develop familiarity with the use of side handles when performing a track start and to use this technique if handles are available on a starting block

    Supporting, microporous, elastomeric degradable prostheses to improve the arterialization of autologous vein grafts

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    Arterial reconstructions with vein grafts fail more frequently than with arterial grafts. One of the causes of graft failure is damage due to overstretching of the graft wall. Overstretching is caused because the vein graft, which has a poorly developed medium, cannot withstand the arterial blood pressures. The aim of this study is to evaluate whether damage due to overstretching can be prevented and a gradual adaptation of the vein graft to the arterial blood pressures can be induced by applying a microporous, elastomeric, degradable prosthesis around the vein graft. Therefore, autologous vein grafts (length 1.0cm) with and without supporting prostheses (composite vein grafts and control vein grafts, respectively) were interposed into both carotid arteries of rabbits. Microporous, elastomeric, biofragmentable polyurethane-based prostheses and microporous, elastomeric, biodegradable prostheses made of poly--caprolactone or a copolymer of -caprolactone and 3.6-dimethyl-1,4-morpholine-2,5-dione with a monomer ratio of 95.5:4.5 were prepared. The grafts were evaluated up to 6 wk after implantation. The control vein grafts showed severe destructive changes such as de-endothelialization, disruption of the media with oedema, degradation of the elastic laminae and infiltration of polymorphonuclear leucocytes into the vein graft wall, leading eventually to a fibrotic wall. In contrast, the composite vein grafts showed a preservation of the smooth muscle cell layers and the elastic laminae with only few polymorphonuclear leucocytes infiltrated into the vein graft wall. Moreover, the wall of the vein graft gradually increased in thickness by the formation of regular circularly oriented cellular layers beneath the original longitudinally oriented smooth muscle cell layers, indicating a gradual adaptation of the vein graft to the arterial conditions. It appeared that the arterialization rate depended on the degradation rate of the supporting prostheses. Microporous prostheses made of a copolymer of -caprolactone and 3,6-dimethyl-1,4-morpholine-2,5-dione with a monomer ratio higher than 95.5:4.5 are recommended to support the vein grafts

    Turnover of microbial lipids in the deep biosphere and growth of benthic archaeal populations

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    Deep subseafloor sediments host a microbial biosphere with unknown impact on global biogeochemical cycles. This study tests previous evidence based on microbial intact polar lipids (IPLs) as proxies of live biomass, suggesting that Archaea dominate the marine sedimentary biosphere: We devised a sensitive radiotracer assay to measure the decay rate of ([C-14]glucosyl)-diphytanylglyceroldiether (GlcDGD) as an analog of archaeal IPLs in continental margin sediments. The degradation kinetics were incorporated in model simulations that constrained the fossil fraction of subseafloor IPLs and rates of archaeal turnover. Simulating the top 1 km in a generic continental margin sediment column, we estimated degradation rate constants of GlcDGD being one to two orders of magnitude lower than those of bacterial IPLs, with half-lives of GlcDGD increasing with depth to 310 ky. Given estimated microbial community turnover times of 1.6-73 ky in sediments deeper than 1 m, 50-96% of archaeal IPLs represent fossil signals. Consequently, previous lipid-based estimates of global subseafloor biomass probably are too high, and the widely observed dominance of archaeal IPLs does not rule out a deep biosphere dominated by Bacteria. Reverse modeling of existing concentration profiles suggest that archaeal IPL synthesis rates decline from around 1,000 pg.mL(-1) sediment.y(-1) at the surface to 0.2 pg.mL(-1).y(-1) at 1 km depth, equivalent to production of 7 x 10(5) to 140 archaeal cells.mL(-1) sediment.y(-1), respectively. These constraints on microbial growth are an important step toward understanding the relationship between the deep biosphere and the carbon cycle
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