2,078 research outputs found

    Assessing quality of plant raising media for organic systems

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    Good quality transplants are vital to growers for a number of reasons. Their ability to better tolerate pest, disease and weed problems and their capacity to make better use of newly incorporated green manures (compared to direct drilling) make them all the more so in organic systems. The availability of high quality growing media is essential to producing healthy vigorous plants, but the organic standards restrict the choice of products available and many growers do not feel they have sufficient information to base their choices. OCW, with support from Farming Connect, coordinated a project to assess the certified products and looked at a green waste based product under development to help address this problem. Growers were supplied with samples of certified products (details provided in the table below) and were asked to test them on range of crops. In order to support this work, scientifically robust trials were carried out by a plant raising specialist on cabbage leek and lettuce

    Hybrid bioprinting of chondrogenically induced human mesenchymal stem cell spheroids

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    To date, the treatment of articular cartilage lesions remains challenging. A promising strategy for the development of new regenerative therapies is hybrid bioprinting, combining the principles of developmental biology, biomaterial science, and 3D bioprinting. In this approach, scaffold-free cartilage microtissues with small diameters are used as building blocks, combined with a photo-crosslinkable hydrogel and subsequently bioprinted. Spheroids of human bone marrow-derived mesenchymal stem cells (hBM-MSC) are created using a high-throughput microwell system and chondrogenic differentiation is induced during 42 days by applying chondrogenic culture medium and low oxygen tension (5%). Stable and homogeneous cartilage spheroids with a mean diameter of 116 +/- 2.80 mu m, which is compatible with bioprinting, were created after 14 days of culture and a glycosaminoglycans (GAG)- and collagen II-positive extracellular matrix (ECM) was observed. Spheroids were able to assemble at random into a macrotissue, driven by developmental biology tissue fusion processes, and after 72 h of culture, a compact macrotissue was formed. In a directed assembly approach, spheroids were assembled with high spatial control using the bio-ink based extrusion bioprinting approach. Therefore, 14-day spheroids were combined with a photo-crosslinkable methacrylamide-modified gelatin (gelMA) as viscous printing medium to ensure shape fidelity of the printed construct. The photo-initiators Irgacure 2959 and Li-TPO-L were evaluated by assessing their effect on bio-ink properties and the chondrogenic phenotype. The encapsulation in gelMA resulted in further chondrogenic maturation observed by an increased production of GAG and a reduction of collagen I. Moreover, the use of Li-TPO-L lead to constructs with lower stiffness which induced a decrease of collagen I and an increase in GAG and collagen II production. After 3D bioprinting, spheroids remained viable and the cartilage phenotype was maintained. Our findings demonstrate that hBM-MSC spheroids are able to differentiate into cartilage microtissues and display a geometry compatible with 3D bioprinting. Furthermore, for hybrid bioprinting of these spheroids, gelMA is a promising material as it exhibits favorable properties in terms of printability and it supports the viability and chondrogenic phenotype of hBM-MSC microtissues. Moreover, it was shown that a lower hydrogel stiffness enhances further chondrogenic maturation after bioprinting

    Service Packaging: Key to Successful Production of Complex ICT Business Services

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    Demand for ICT services is increasing at the same time as the services are becoming more complex and customer requests more unique. The resulting complexity creates severe problems for service providers. This paper introduces three service design and development methods - service industrialization, tangibilization, and service blueprinting - and describes how they can be used to reduce the complexity of ICT services through a case study of an ICT service provider. The results offer significant theoretical and managerial implications for the design and production of complex business services

    Modular plant culture systems for life support functions

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    The current state of knowledge with regard to culture of higher plants in the zero-G environment is assessed; and concepts for the empirical development of small plant growth chambers for the production of salad type vegetables on space shuttle or space station are evaluated. American and Soviet space flight experiences in gravitational biology are summarized

    Effectiveness of Nitrate Policy in Flanders (1990-2003): Modular Modelling and Response Analysis

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    The impact of current nitrate policy measures in Flanders is estimated. A modular modelling system has been developed for comparing response and pressure indicators and for decomposing the response impact of policy measures. Compared to 1990, the internalised manure surplus is reduced to zero, whereas the distance to target of the soil surface balance to the water quality standard dropped only with 58%. Source-linked and sink-related measures each account for about the half of the manure surplus reduction. The impact of abatement technologies is minor. The modular approach helps to unravel the discrepancy between pressure and response and to propose policy alternatives.abatement technology, DPSIR scheme, nitrogen pollution reduction, Agricultural and Food Policy, B41, C51, H21, K32,

    Collective motion of cells: from experiments to models

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    Swarming or collective motion of living entities is one of the most common and spectacular manifestations of living systems having been extensively studied in recent years. A number of general principles have been established. The interactions at the level of cells are quite different from those among individual animals therefore the study of collective motion of cells is likely to reveal some specific important features which are overviewed in this paper. In addition to presenting the most appealing results from the quickly growing related literature we also deliver a critical discussion of the emerging picture and summarize our present understanding of collective motion at the cellular level. Collective motion of cells plays an essential role in a number of experimental and real-life situations. In most cases the coordinated motion is a helpful aspect of the given phenomenon and results in making a related process more efficient (e.g., embryogenesis or wound healing), while in the case of tumor cell invasion it appears to speed up the progression of the disease. In these mechanisms cells both have to be motile and adhere to one another, the adherence feature being the most specific to this sort of collective behavior. One of the central aims of this review is both presenting the related experimental observations and treating them in the light of a few basic computational models so as to make an interpretation of the phenomena at a quantitative level as well.Comment: 24 pages, 25 figures, 13 reference video link

    Coordinating the Relationship between IT Services Providers and Clients: The Case of Cloud Computing

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    The focus of this research is on the IT service relationships that exist between clients and providers in cloud computing. Cloud computing is an important context in IT services management since it has become an increasingly popular delivery model. We use coordination theory and a case study of a cloud computing-based company to investigate how cloud service relationships are managed. Evidence of both the standardized and customized relationships is based on a case study of SiteWit, a new startup company that is both a user and provider of cloud services. This company is an interesting case to study, given the real-time, intensive nature of the technical demands, the multiple service relationships that must be managed, while at the same time minimizing costs

    Engineering of In Vitro 3D Capillary Beds by Self-Directed Angiogenic Sprouting

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    In recent years, microfluidic systems have been used to study fundamental aspects of angiogenesis through the patterning of single-layered, linear or geometric vascular channels. In vivo, however, capillaries exist in complex, three-dimensional (3D) networks, and angiogenic sprouting occurs with a degree of unpredictability in all x,y,z planes. The ability to generate capillary beds in vitro that can support thick, biological tissues remains a key challenge to the regeneration of vital organs. Here, we report the engineering of 3D capillary beds in an in vitro microfluidic platform that is comprised of a biocompatible collagen I gel supported by a mechanical framework of alginate beads. The engineered vessels have patent lumens, form robust ~1.5 mm capillary networks across the devices, and support the perfusion of 1 µm fluorescent beads through them. In addition, the alginate beads offer a modular method to encapsulate and co-culture cells that either promote angiogenesis or require perfusion for cell viability in engineered tissue constructs. This laboratory-constructed vascular supply may be clinically significant for the engineering of capillary beds and higher order biological tissues in a scalable and modular manner.Singapore-MIT Alliance for Research and Technolog
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