146 research outputs found

    Guidelines for the use of cell lines in biomedical research

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    Cell-line misidentification and contamination with microorganisms, such as mycoplasma, together with instability, both genetic and phenotypic, are among the problems that continue to affect cell culture. Many of these problems are avoidable with the necessary foresight, and these Guidelines have been prepared to provide those new to the field and others engaged in teaching and instruction with the information necessary to increase their awareness of the problems and to enable them to deal with them effectively. The Guidelines cover areas such as development, acquisition, authentication, cryopreservation, transfer of cell lines between laboratories, microbial contamination, characterisation, instability and misidentification. Advice is also given on complying with current legal and ethical requirements when deriving cell lines from human and animal tissues, the selection and maintenance of equipment and how to deal with problems that may arise

    Specifying and Analysing SOC Applications with COWS

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    COWS is a recently defined process calculus for specifying and combining service-oriented applications, while modelling their dynamic behaviour. Since its introduction, a number of methods and tools have been devised to analyse COWS specifications, like e.g. a type system to check confidentiality properties, a logic and a model checker to express and check functional properties of services. In this paper, by means of a case study in the area of automotive systems, we demonstrate that COWS, with some mild linguistic additions, can model all the phases of the life cycle of service-oriented applications, such as publication, discovery, negotiation, orchestration, deployment, reconfiguration and execution. We also provide a flavour of the properties that can be analysed by using the tools mentioned above

    National Early Warning Score Accurately Discriminates the Risk of Serious Adverse Events in Patients With Liver Disease.

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    BACKGROUND & AIMS: The National Early Warning Score (NEWS) is used to identify deteriorating adult hospital inpatients. However, it includes physiological parameters frequently altered in patients with cirrhosis. We aimed to assess the performance of the NEWS in acute and chronic liver diseases. METHODS: We collected vital signs, recorded in real time, from completed consecutive admissions of patients 16 years or older to a large acute-care hospital in Southern England, from January 1, 2010, through October 31, 2014. Using International Classification of Diseases, 10th revision, codes, we categorized patients as having primary liver disease, secondary liver disease, or none. For patients with liver disease, 2 analysis groups were developed: the first was based on clinical group (such as acute or chronic, alcohol-induced, or associated with portal hypertension), and the second was based on a summary of liver-related, hospital-level mortality indicator diagnoses. For each, we compared the abilities of the NEWS and 34 other early warning scores to discriminate 24-hour mortality, cardiac arrest, or unanticipated admission to the intensive care unit using the area under the receiver operating characteristic (AUROC) curve and early warning score efficiency curve analyses. RESULTS: The NEWS identified patients with primary, nonprimary, and no diagnoses of liver disease with AUROC values of 0.873 (95% CI, 0.860-0.886), 0.898 (95% CI, 0.891-0.905), and 0.879 (95% CI, 0.877-0.881), respectively. High AUROC values were also obtained for all clinical subgroups; the NEWS identified patients with alcohol-related liver disease with an AUROC value of 0.927 (95% CI, 0.912-0.941). The NEWS identified patients with liver diseases with higher AUROC values than other early warning scoring systems. CONCLUSIONS: The NEWS accurately discriminates patients at risk of death, admission to the intensive care unit, or cardiac arrest within a 24-hour period for a range of liver-related diagnoses. Its widespread use provides a ready-made, easy-to-use option for identifying patients with liver disease who require early assessment and intervention, without the need to modify parameters, weightings, or escalation criteria

    Effects of machine stiffness and cutting tool design on the surface quality and flexural strength of edge trimmed carbon fibre reinforced polymers

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    A 22 full factorial design of experiment is used to investigate the effects of two machining platforms (5-axis elevated gantry versus 6-axis articulated robotic system) and two cutting tool designs (burr versus herringbone) on surface metrics and flexural strength of a 14 ply T300 2x2 carbon fibre reinforced polymer. A range of areal metrics were considered to characterise the surface with Sal and Stdi best able to represent differences due to the choice of robotic system or overhead gantry. The robotic system produces coupons with flexural strengths up to 26% higher than the overhead gantry. The choice of tool has a less significant effect however machine-tool interactions do play a role in the flexural strength. Analysis using scanning electron microscopy shows that defects may be obscured by smeared matrix which may contribute to overall flexural strength differences

    International survey on high- and low-dose synacthen test and assessment of accuracy in preparing low-dose synacthen

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    OBJECTIVE: The short synacthen test (SST) is widely used to assess patients for adrenal insufficiency but the frequency and protocols used across different centres for the low-dose test (LDT) are unknown. This study aimed to survey centres and test the accuracy of ten different synacthen preparation strategies used for the LDT. METHODS: Members of six international endocrine societies were surveyed regarding diagnostic tests used for adrenal insufficiency, and in particular the SST. Synacthen was diluted for the LDT and concentrations measured using a synacthen ELISA. RESULTS: Survey responses were received from 766 individuals across 60 countries (52% adult, 45% paediatric endocrinologists). The SST is used by 98% of centres: 92% using high-dose (250 μg), 43% low-dose, and 37% both. Ten low-dose dilution methods were assessed and variation in synacthen concentration was demonstrated with intra-method coefficients of variation (CV) ranging from 2.1% to 109%. The method using 5% dextrose as a diluent was the least variable (CV of 2.1%). The variation in dilution methods means that the dose of synacthen administered in a LDT may vary between 0.16 μg and 0.81 μg. CONCLUSIONS: The high-dose SST is the most popular diagnostic test of adrenal insufficiency but up to 72% of paediatric endocrinologists use a LDT. There is considerable variation observed both within and between low-dose synacthen dilution methods creating considerable risk of inaccurate dosing and thereby invalid results

    RGDS peptides immobilized on titanium alloy stimulate bone cell attachment, differentiation and confer resistance to apoptosis

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    A major cause of implant failure in skeletal tissues is failure of osseointegration, often due to lack of adhesion of cells to the titanium (Ti) alloy interface. Since arginine- glycine-aspartic acid (RGD)-containing peptides have been shown to regulate osteoblast adhesion, we tested the hypothesis that, bound to a Ti surface, these peptides would promote osteoblasts differentiation, while at the same time inhibit apoptosis. RGDS and RGES (control) peptides were covalently linked to Ti discs using an APTS linker. While the grafting of both RGDS and RGES significantly increased Ti surface roughness, contact angle analysis showed that APTS significantly increased the surface hydrophobicity; when the peptides were tethered to Ti, this was reduced. To evaluate attachment, MC3T3-E1 osteoblast cells were grown on these discs. Significantly more cells attached to the Ti-grafted RGDS then the Ti-grafted RGES control. Furthermore, expression of the osteoblasts phenotype was significantly enhanced on the Ti-grafted RGDS surface. When cells attached to the Ti-grafted RGDS were challenged with staurosporine, an apoptogen, there was significant inhibition of apoptosis; in contrast, osteoblasts adherent to the Ti-grafted RGES were killed. It is concluded that RGD-containing peptides covalently bonded to Ti promotes osteoblasts attachment and survival with minimal changes to the surface of the alloy. Therefore, such modifications to Ti would have the potential to promote osseointegration in vivo

    Microvawe pyrolysis of biomass: control of process parameters for high pyrolysis oil yields and enhanced oil quality

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    The oil yield and quality of pyrolysis oil from microwave heating of biomass was established by studying the behaviour of Larch in microwave processing. This is the first study in biomass pyrolysis to use a microwave processing technique and methodology that is fundamentally scalable, from which the basis of design for a continuous processing system can be derived to maximise oil yield and quality. It is shown systematically that sample size is a vital parameter that has been overlooked by previous work in this field. When sample size is controlled the liquid product yield is comparable to conventional pyrolysis, and can be achieved at an energy input of around 600 kWh/t. The quality of the liquid product is significantly improved compared to conventional pyrolysis processes, which results from the very rapid heating and quenching that can be achieved with microwave processing. The yields of Levoglucosan and phenolic compounds were found to be an order of magnitude higher in microwave pyrolysis when compared with conventional fast pyrolysis. Geometry is a key consideration for the development of a process at scale, and the opportunities and challenges for scale-up are discussed within this paper

    Extreme events and predictability of catastrophic failure in composite materials and in the Earth

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    Despite all attempts to isolate and predict extreme earthquakes, these nearly always occur without obvious warning in real time: fully deterministic earthquake prediction is very much a ‘black swan’. On the other hand engineering-scale samples of rocks and other composite materials often show clear precursors to dynamic failure under controlled conditions in the laboratory, and successful evacuations have occurred before several volcanic eruptions. This may be because extreme earthquakes are not statistically special, being an emergent property of the process of dynamic rupture. Nevertheless, probabilistic forecasting of event rate above a given size, based on the tendency of earthquakes to cluster in space and time, can have significant skill compared to say random failure, even in real-time mode. We address several questions in this debate, using examples from the Earth (earthquakes, volcanoes) and the laboratory, including the following. How can we identify ‘characteristic’ events, i.e. beyond the power law, in model selection (do dragon-kings exist)? How do we discriminate quantitatively between stationary and non-stationary hazard models (is a dragon likely to come soon)? Does the system size (the size of the dragon’s domain) matter? Are there localising signals of imminent catastrophic failure we may not be able to access (is the dragon effectively invisible on approach)? We focus on the effect of sampling effects and statistical uncertainty in the identification of extreme events and their predictability, and highlight the strong influence of scaling in space and time as an outstanding issue to be addressed by quantitative studies, experimentation and models

    Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

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    We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe
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