56 research outputs found

    The manufacture of synthetic non-sintered and degradable bone grafting substitutes

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    A new synthetic bone grafting substitute (NanoBone®, ARTOSS GmbH, Germany) is presented. This is produced by a new technique, the sol-gel-method. This bone grafting substitute consists of nanocrystalline hydroxyapatite (HA) and nanostructured silica (SiO2). By achieving a highly porous structure good osteoconductivity can be seen. In addition, the material will be completely biodegraded and new own bone is formed. It has been demonstrated that NanoBone® is biodegraded by osteoclasts in a manner comparable to the natural bone remodelling process

    Mathematical modeling of cell population dynamics in the colonic crypt and in colorectal cancer

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    Colorectal cancer is initiated in colonic crypts. A succession of genetic mutations or epigenetic changes can lead to homeostasis in the crypt being overcome, and subsequent unbounded growth. We consider the dynamics of a single colorectal crypt by using a compartmental approach [Tomlinson IPM, Bodmer WF (1995) Proc Natl Acad Sci USA 92: 11130-11134], which accounts for populations of stem cells, differential cells, and transit cells. That original model made the simplifying assumptions that each cell popuation divides synchronously, but we relax these assumptions by adopting an age-structured approach that models asynchronous cell division, and by using a continuum model. We discuss two mechanims that could regulate the growth of cell numbers and maintain the equilibrium that is normally observed in the crypt. The first will always maintain an equilibrium for all parameter values, whereas the second can allow unbounded proliferation if the net per capita growth rates are large enough. Results show that an increase in cell renewal, which is equivalent to a failure of programmed cell death or of differentiation, can lead to the growth of cancers. The second model can be used to explain the long lag phases in tumor growth, during which news, higher equilibria are reached, before unlimited growth in cell number ensues

    The Smart City Active Mobile Phone Intervention (SCAMPI) study to promote physical activity through active transportation in healthy adults: a study protocol for a randomised controlled trial

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    Abstract Background The global pandemic of physical inactivity represents a considerable public health challenge. Active transportation (i.e., walking or cycling for transport) can contribute to greater total physical activity levels. Mobile phone-based programs can promote behaviour change, but no study has evaluated whether such a program can promote active transportation in adults. This study protocol presents the design and methodology of The Smart City Active Mobile Phone Intervention (SCAMPI), a randomised controlled trial to promote active transportation via a smartphone application (app) with the aim to increase physical activity. Methods/design A two-arm parallel randomised controlled trial will be conducted in Stockholm County, Sweden. Two hundred fifty adults aged 20–65 years will be randomised to either monitoring of active transport via the TRavelVU app (control), or to a 3-month evidence-based behaviour change program to promote active transport and monitoring of active travel via the TRavelVU Plus app (intervention). The primary outcome is moderate-to-vigorous intensity physical activity (MVPA in minutes/day) (ActiGraph wGT3x-BT) measured post intervention. Secondary outcomes include: time spent in active transportation measured via the TRavelVU app, perceptions about active transportation (the Transport and Physical Activity Questionnaire (TPAQ)) and health related quality of life (RAND-36). Assessments are conducted at baseline, after the completed intervention (after 3 months) and 6 months post randomisation. Discussion SCAMPI will determine the effectiveness of a smartphone app to promote active transportation and physical activity in an adult population. If effective, the app has potential to be a low-cost intervention that can be delivered at scale. Trial registration ClinicalTrials.gov NCT03086837; 22 March, 2017

    Micropatterned Thermoresponsive Cell Culture Substrates for Dynamically Controlling Neurite Outgrowth and Neuronal Connectivity in Vitro

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    In vitro cultured neuronal networks with defined connectivity are required to improve neuronal cell culture models. However, most protocols for their formation do not provide sufficient control of the direction and timing of neurite outgrowth with simultaneous access for analytical tools such as immunocytochemistry or patch-clamp recordings. Here, we present a proof-of-concept for the dynamic (i.e., time-gated) control of neurite outgrowth on a cell culture substrate based on 2D-micropatterned coatings of thermoresponsive polymers (TRP). The pattern consists of uncoated microstructures where neurons can readily adhere and neurites can extend along defined pathways. The surrounding regions are coated with TRP that does not facilitate cell or neurite growth at 33 °C. Increasing the ambient temperature to 37 °C renders the TRP coating cell adhesive and enables the crossing of gaps coated with TRP by neurites to contact neighboring cells. Here, we demonstrate the realization of this approach employing human neuronal SH-SY5Y cells and human induced neuronal cells. Our results suggest that this approach may help to establish a spatiotemporal control over the connectivity of multinodal neuronal networks

    The European Sero-Epidemiology Network: standardizing the enzyme immunoassay results for measles, mumps and rubella

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    The ESEN (European Sero-Epidemiology Network) project was established to harmonize the seroepidemiology of five vaccine preventable infections including measles, mumps and rubella in eight European countries. This involved achieving comparability both in the assay results from testing in different centres and also sampling methodology. Standardization of enzyme immunoassay results was achieved through the development of common panels of sera by designated reference centres. The panels were tested at the reference laboratory and then distributed to each participating laboratory for testing using their routine methods. Standardization equations were calculated by regressing the quantitative results against those of the reference laboratory. Our study found large differences in unitage between participants, despite all using an EIA method standardized against an international or local standard. Moreover, our methodology adjusted for this difference. These standardization equations will be used to convert the results of main serosurvey testing into the reference country unitage to ensure inter-country comparability
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