2,294 research outputs found

    Effect of egg turning and incubation time on carbonic anhydrase gene expression in the blastoderm of the Japanese quail (Coturnix c. japonica)

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    (1) The gene expression of carbonic anhydrase, a key enzyme for the production sub-embryonic fluid (SEF), was assessed in turned and unturned eggs of the Japanese quail. The plasma membrane-associated isoforms CA IV, CAIX, CA XII, CA XIV, and the cytoplasmic isoform CA II, were investigated in the extra-embryonic tissue of the blastoderm and in embryonic blood. (2) Eggs were incubated at 37.6C, c. 60% R.H., and turned hourly (90 ) or left unturned. From 48 to 96 hours of incubation mRNA was extracted from blastoderm tissue, reverse-transcribed to cDNA and quantified by real-time qPCR using gene-specific primers. Blood collected at 96h was processed identically. (3) Blastoderm CAIV gene expression increased with the period of incubation only in turned eggs, with maxima at 84 and 96h of incubation. Only very low levels were found in blood. (4) Blastoderm CA II gene expression was greatest at 48 and 54h of incubation, subsequently declining to much lower levels and una ected by turning. Blood CA II gene expression was about 25-fold greater than that in the blastoderm. (5) The expression of CA IX in the blastoderm was the highest of all isoforms, yet unaffected by turning. CA XII did not amplify and CA XIV was present at unquantifiable low levels. (6) It is concluded that solely gene expression for CA IV is sensitive to egg turning, and that increased CA IV gene expression could account for the additional SEF mass found at 84-96h of incubation. in embryos of turned eggs

    Exploring the spatialities of technological and user re-scripting: The case of decision support tools in UK agriculture

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    The use of decision support tools on-farm may help to deliver evidence-based guidance to farmers, helping to improve productivity and prevent environmental degradation. While much research has sought to increase the uptake of decision support tools in practice, largely by identifying desirable characteristics of system design, rather little work has used a spatial lens to investigate how they are actually used. Using Latour’s notion of ‘the script’, this paper looks at the spatialities of technological and user re-scripting associated with the introduction of decision support tools on-farm. Although there is some literature on how technologies may be re-scripted by users, studies concerning decision support tools are more limited. Furthermore, while there are studies about how technology (not decision support tools) re-scripts agricultural societies, these are generally concerned with macro-level impacts (e.g. labour changes), rather than exploring life on individual farms. This paper, therefore, focuses on exploring the spatialities of re-scripting, investigating how tools themselves are co-constituted in various ways by different users in different spaces, but more particularly on how life on the farm may be changed by the introduction of decision tools. A case study of decision support tool use on farms in England and Wales demonstrates the need to explore spaces on individual farms if we wish to understand processes occurring at the interface between tools and farmers. Firstly, situated knowledge held by farmers and advisers leads to resistance, negotiation, and re-scripting of decision support tools, which are perceived to provide the ‘view from nowhere’. Secondly, the introduction of decision support tools changes the workflows of farmers, affecting how and when they interact with different spaces of their farm. In signalling the need for more research to theorise the spatialities of re-scripting, we briefly explore how our work can inform policy and the development of decision support tools

    Exploring the spatialities of technological and user re-scripting: The case of decision support tools in UK agriculture

    Get PDF
    The use of decision support tools on-farm may help to deliver evidence-based guidance to farmers, helping to improve productivity and prevent environmental degradation. While much research has sought to increase the uptake of decision support tools in practice, largely by identifying desirable characteristics of system design, rather little work has used a spatial lens to investigate how they are actually used. Using Latour’s notion of ‘the script’, this paper looks at the spatialities of technological and user re-scripting associated with the introduction of decision support tools on-farm. Although there is some literature on how technologies may be re-scripted by users, studies concerning decision support tools are more limited. Furthermore, while there are studies about how technology (not decision support tools) re-scripts agricultural societies, these are generally concerned with macro-level impacts (e.g. labour changes), rather than exploring life on individual farms. This paper, therefore, focuses on exploring the spatialities of re-scripting, investigating how tools themselves are co-constituted in various ways by different users in different spaces, but more particularly on how life on the farm may be changed by the introduction of decision tools. A case study of decision support tool use on farms in England and Wales demonstrates the need to explore spaces on individual farms if we wish to understand processes occurring at the interface between tools and farmers. Firstly, situated knowledge held by farmers and advisers leads to resistance, negotiation, and re-scripting of decision support tools, which are perceived to provide the ‘view from nowhere’. Secondly, the introduction of decision support tools changes the workflows of farmers, affecting how and when they interact with different spaces of their farm. In signalling the need for more research to theorise the spatialities of re-scripting, we briefly explore how our work can inform policy and the development of decision support tools

    Control of interjoint coordination during the swing phase of normal gait at different speeds

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    BACKGROUND: It has been suggested that the control of unconstrained movements is simplified via the imposition of a kinetic constraint that produces dynamic torques at each moving joint such that they are a linear function of a single motor command. The linear relationship between dynamic torques at each joint has been demonstrated for multijoint upper limb movements. The purpose of the current study was to test the applicability of such a control scheme to the unconstrained portion of the gait cycle – the swing phase. METHODS: Twenty-eight neurologically normal individuals walked along a track at three different speeds. Angular displacements and dynamic torques produced at each of the three lower limb joints (hip, knee and ankle) were calculated from segmental position data recorded during each trial. We employed principal component (PC) analysis to determine (1) the similarity of kinematic and kinetic time series at the ankle, knee and hip during the swing phase of gait, and (2) the effect of walking speed on the range of joint displacement and torque. RESULTS: The angular displacements of the three joints were accounted for by two PCs during the swing phase (Variance accounted for – PC1: 75.1 ± 1.4%, PC2: 23.2 ± 1.3%), whereas the dynamic joint torques were described by a single PC (Variance accounted for – PC1: 93.8 ± 0.9%). Increases in walking speed were associated with increases in the range of motion and magnitude of torque at each joint although the ratio describing the relative magnitude of torque at each joint remained constant. CONCLUSION: Our results support the idea that the control of leg swing during gait is simplified in two ways: (1) the pattern of dynamic torque at each lower limb joint is produced by appropriately scaling a single motor command and (2) the magnitude of dynamic torque at all three joints can be specified with knowledge of the magnitude of torque at a single joint. Walking speed could therefore be altered by modifying a single value related to the magnitude of torque at one joint

    Understanding the regulation of aspartate metabolism using a model based on measured kinetic parameters

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    The aspartate-derived amino-acid pathway from plants is well suited for analysing the function of the allosteric network of interactions in branched pathways. For this purpose, a detailed kinetic model of the system in the plant model Arabidopsis was constructed on the basis of in vitro kinetic measurements. The data, assembled into a mathematical model, reproduce in vivo measurements and also provide non-intuitive predictions. A crucial result is the identification of allosteric interactions whose function is not to couple demand and supply but to maintain a high independence between fluxes in competing pathways. In addition, the model shows that enzyme isoforms are not functionally redundant, because they contribute unequally to the flux and its regulation. Another result is the identification of the threonine concentration as the most sensitive variable in the system, suggesting a regulatory role for threonine at a higher level of integration

    Structural basis for the RING catalyzed synthesis of K63 linked ubiquitin chains

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    This work was supported by grants from Cancer Research UK (C434/A13067), the Wellcome Trust (098391/Z/12/Z) and Biotechnology and Biological Sciences Research Council (BB/J016004/1).The RING E3 ligase catalysed formation of lysine 63 linked ubiquitin chains by the Ube2V2–Ubc13 E2 complex is required for many important biological processes. Here we report the structure of the RING domain dimer of rat RNF4 in complex with a human Ubc13~Ub conjugate and Ube2V2. The structure has captured Ube2V2 bound to the acceptor (priming) ubiquitin with Lys63 in a position that could lead to attack on the linkage between the donor (second) ubiquitin and Ubc13 that is held in the active “folded back” conformation by the RING domain of RNF4. The interfaces identified in the structure were verified by in vitro ubiquitination assays of site directed mutants. This represents the first view of the synthesis of Lys63 linked ubiquitin chains in which both substrate ubiquitin and ubiquitin-loaded E2 are juxtaposed to allow E3 ligase mediated catalysis.PostprintPeer reviewe

    Protocol for a multicentre randomised feasibility trial evaluating early Surgery Alone In LOw Rectal cancer (SAILOR)

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    Introduction There are 11,500 rectal cancers diagnosed annually in the UK. Although surgery remains the primary treatment there is evidence that preoperative radiotherapy (RT) improves local recurrence rates. High quality surgery in rectal cancer is equally important in minimising local recurrence. Advances in magnetic resonance imaging (MRI)-guided prediction of resection margin status and improvements in abdominoperineal excision of the rectum (APER) technique supports a reassessment of the contribution of preoperative RT. A more selective approach to RT may be appropriate given the associated toxicity. Methods and analysis This trial will explore the feasibility of a definitive trial evaluating the omission of RT in resectable low rectal cancer requiring APER. It will test the feasibility of randomising patients to i) standard care (neoadjuvant long course radiotherapy +/- chemotherapy and APER, or ii) APER surgery alone for cT2/T3ab N0/1 low rectal cancer with clear predicted resection margins on MRI. Radiotherapy schedule will be 45Gy over 5 weeks as current standard, with restaging and surgery after 8-12 weeks. Recruitment will be for 24 months with a minimum 12 month follow up. Objectives include testing the ability to recruit, consent and retain patients, to quantify the number of patients eligible for a definitive trial and to test feasibility of outcomes measures. These include locoregional recurrence rates, distance to circumferential resection margin, toxicity and surgical complications including perineal wound healing, quality of life and economic analysis. The quality of MRI staging, radiotherapy delivery and surgical specimen quality will be closely monitored. Ethics and dissemination The trial is approved by the regional ethics committee and Health Research Authority (HRA) or equivalent. Written informed consent will be obtained. Serious adverse events will be reported to Swansea Trials Unit (STU), the ethics committee and trial sites. Trial results will be submitted for peer review publication and to trial participants. Strengths and limitations of this study • A unique interventional study specific to low rectal cancer • Will explore the contribution of the modern abdominoperineal excision operation to cancer outcomes • Strict quality assurance processes for imaging, radiotherapy, surgery and pathology • Will establish if a future trial minimising radiotherapy use in low rectal cancer is feasible • Study is limited by short follow up perio
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