4,810 research outputs found

    Digital Availability of Product Information for Collaborative Engineering of Spacecraft

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    In this paper, we introduce a system to collect product information from manufacturers and make it available in tools that are used for concurrent design of spacecraft. The planning of a spacecraft needs experts from different disciplines, like propulsion, power, and thermal. Since these different disciplines rely on each other there is a high need for communication between them, which is often realized by a Model-Based Systems Engineering (MBSE) process and corresponding tools. We show by comparison that the product information provided by manufacturers often does not match the information needed by MBSE tools on a syntactic or semantic level. The information from manufacturers is also currently not available in machine-readable formats. Afterwards, we present a prototype of a system that makes product information from manufacturers directly available in MBSE tools, in a machine-readable way.Comment: accepted at CDVE201

    Development of a common carp (Cyprinus carpio) pregnane X receptor (cPXR) transactivation reporter assay and its activation by azole fungicides and pharmaceutical chemicals.

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.In mammals, the pregnane X receptor (PXR) is a transcription factor with a key role in regulating expression of several genes involved in drug biotransformation. PXR is present in fish and some genes known to be under its control can be up-regulated by mammalian PXR ligands. Despite this, direct involvement of PXR in drug biotransformation in fish has yet to be established. Here, the full length PXR sequence was cloned from carp (Cyprinus carpio) and used in a luciferase reporter assay to elucidate its role in xenobiotic metabolism in fish. A reporter assay for human PXR (hPXR) was also established to compare transactivation between human and carp (cPXR) isoforms. Rifampicin activated hPXR as expected, but not cPXR. Conversely, clotrimazole (CTZ) activated both isoforms and was more potent on cPXR, with an EC50 within the range of concentrations of CTZ measured in the aquatic environment. Responses to other azoles tested were similar between both isoforms. A range of pharmaceuticals tested either failed to activate, or were very weakly active, on the cPXR or hPXR. Overall, these results indicate that the cPXR may differ from the hPXR in its responses and/or sensitivity to induction by different environmental chemicals, with implications for risk assessment because of species differences.JC was funded by a Biotechnology and Biological Sciences Research Council Case studentship supported by AstraZeneca UK Ltd. (grant reference BB/G529332), and co-supported by the AstraZeneca Safety Health and Environment Research Program. AL was supported by grants from the Natural Environment Research Council (NE/D002818/1 and NE/E016634/1) and DEFRA awarded to CRT. Defra (UK) funded a research visit of SM to the University of Exeter under the UK-J programme. COS-7 cells were a gift from Inês Castro, University of Exeter. AstraZeneca Ltd. develops, produces, and markets a wide range of pharmaceutical agents

    Long-time Low-latency Quantum Memory by Dynamical Decoupling

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    Quantum memory is a central component for quantum information processing devices, and will be required to provide high-fidelity storage of arbitrary states, long storage times and small access latencies. Despite growing interest in applying physical-layer error-suppression strategies to boost fidelities, it has not previously been possible to meet such competing demands with a single approach. Here we use an experimentally validated theoretical framework to identify periodic repetition of a high-order dynamical decoupling sequence as a systematic strategy to meet these challenges. We provide analytic bounds-validated by numerical calculations-on the characteristics of the relevant control sequences and show that a "stroboscopic saturation" of coherence, or coherence plateau, can be engineered, even in the presence of experimental imperfection. This permits high-fidelity storage for times that can be exceptionally long, meaning that our device-independent results should prove instrumental in producing practically useful quantum technologies.Comment: abstract and authors list fixe

    Level of arterial ligation in total mesorectal excision (TME): an anatomical study

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    Introduction: High-tie ligation is a common practice in rectal cancer surgery. However, it compromises perfusion of the proximal limb of the anastomosis. This anatomical study was designed to assess the value of low-tie ligation in order to obtain a tension-free anastomosis. Materials and methods: Consecutive high- and low-tie resections were performed on 15 formalin-fixed specimens, with or without splenic flexure mobilization. If the proximal colon limb could reach the superior aspect of the symphysis pubis with more than 3 cm, the limb would be long enough for a tension-free colorectal anastomosis. Results: In 80% of cases, it was not necessary to perform high-tie ligation as sufficient length was gained with low-tie ligation. The descending branch of the left colic artery was the limiting factor in the other 20% of cases. Resecting half the sigmoid resulted in four times as many tension-free anastomoses after low-tie resection. Conclusion: In the majority of cases, it was not necessary to perform high-tie ligation in order to create a tension-free anastomosis. Low-tie ligation was applicable in 80% of cases and might prevent anastomotic leakage due to insufficient blood supply of the proximal colon limb

    Exposure Effects of Environmentally Relevant Concentrations of the Tricyclic Antidepressant, Amitriptyline in Early Life Stage Zebrafish

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    This is the final version. Available from the American Chemical Society via the DOI in this record. Antidepressants are one of the most globally prescribed classes of pharmaceuticals, and drug target conservation across phyla means that nontarget organisms may be at risk from the effects of exposure. Here, we address the knowledge gap for the effects of chronic exposure (28 days) to the tricyclic antidepressant amitriptyline (AMI) on fish, including for concentrations with environmental relevance, using zebrafish (Danio rerio) as our experimental model. AMI was found to bioconcentrate in zebrafish, readily transformed to its major active metabolite nortriptyline, and induced a pharmacological effect (down- regulation of the gene encoding the serotonin transporter; slc6a4a) at environmentally relevant concentrations (0.03 μg/L and above). Exposures to AMI at higher concentrations accelerated the hatch rate and reduced activity levels, the latter of which was abolished after a 14 day period of depuration. The lack of any response on the features of physiology and behavior we measured at concentrations found in the environment would indicate that AMI poses a relatively low level of risk to fish populations. The pseudopersistence and likely presence of multiple drugs acting via the same mechanism of action, however, together with a global trend for increased prescription rates, mean that this risk may be underestimated using current ecotoxicological assessment paradigms.Innovative Medicines Initiative (IMI) Joint UndertakingEU’s Seventh Framework ProgrammeEuropean Federation of Pharmaceutical Industries and Associations (EFPIA)MerckUniversity of Exete

    Direct and indirect control of the initiation of meiotic recombination by DNA damage checkpoint mechanisms in budding yeast

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    Meiotic recombination plays an essential role in the proper segregation of chromosomes at meiosis I in many sexually reproducing organisms. Meiotic recombination is initiated by the scheduled formation of genome-wide DNA double-strand breaks (DSBs). The timing of DSB formation is strictly controlled because unscheduled DSB formation is detrimental to genome integrity. Here, we investigated the role of DNA damage checkpoint mechanisms in the control of meiotic DSB formation using budding yeast. By using recombination defective mutants in which meiotic DSBs are not repaired, the effect of DNA damage checkpoint mutations on DSB formation was evaluated. The Tel1 (ATM) pathway mainly responds to unresected DSB ends, thus the sae2 mutant background in which DSB ends remain intact was employed. On the other hand, the Mec1 (ATR) pathway is primarily used when DSB ends are resected, thus the rad51 dmc1 double mutant background was employed in which highly resected DSBs accumulate. In order to separate the effect caused by unscheduled cell cycle progression, which is often associated with DNA damage checkpoint defects, we also employed the ndt80 mutation which permanently arrests the meiotic cell cycle at prophase I. In the absence of Tel1, DSB formation was reduced in larger chromosomes (IV, VII, II and XI) whereas no significant reduction was found in smaller chromosomes (III and VI). On the other hand, the absence of Rad17 (a critical component of the ATR pathway) lead to an increase in DSB formation (chromosomes VII and II were tested). We propose that, within prophase I, the Tel1 pathway facilitates DSB formation, especially in bigger chromosomes, while the Mec1 pathway negatively regulates DSB formation. We also identified prophase I exit, which is under the control of the DNA damage checkpoint machinery, to be a critical event associated with down-regulating meiotic DSB formation

    Decoherence-protected quantum gates for a hybrid solid-state spin register

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    Protecting the dynamics of coupled quantum systems from decoherence by the environment is a key challenge for solid-state quantum information processing. An idle qubit can be efficiently insulated from the outside world via dynamical decoupling, as has recently been demonstrated for individual solid-state qubits. However, protection of qubit coherence during a multi-qubit gate poses a non-trivial problem: in general the decoupling disrupts the inter-qubit dynamics, and hence conflicts with gate operation. This problem is particularly salient for hybrid systems, wherein different types of qubits evolve and decohere at vastly different rates. Here we present the integration of dynamical decoupling into quantum gates for a paradigmatic hybrid system, the electron-nuclear spin register. Our design harnesses the internal resonance in the coupled-spin system to resolve the conflict between gate operation and decoupling. We experimentally demonstrate these gates on a two-qubit register in diamond operating at room temperature. Quantum tomography reveals that the qubits involved in the gate operation are protected as accurately as idle qubits. We further illustrate the power of our design by executing Grover's quantum search algorithm, achieving fidelities above 90% even though the execution time exceeds the electron spin dephasing time by two orders of magnitude. Our results directly enable decoherence-protected interface gates between different types of promising solid-state qubits. Ultimately, quantum gates with integrated decoupling may enable reaching the accuracy threshold for fault-tolerant quantum information processing with solid-state devices.Comment: This is original submitted version of the paper. The revised and finalized version is in print, and is subjected to the embargo and other editorial restrictions of the Nature journa

    Sensing electric fields using single diamond spins

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    The ability to sensitively detect charges under ambient conditions would be a fascinating new tool benefitting a wide range of researchers across disciplines. However, most current techniques are limited to low-temperature methods like single-electron transistors (SET), single-electron electrostatic force microscopy and scanning tunnelling microscopy. Here we open up a new quantum metrology technique demonstrating precision electric field measurement using a single nitrogen-vacancy defect centre(NV) spin in diamond. An AC electric field sensitivity reaching ~ 140V/cm/\surd Hz has been achieved. This corresponds to the electric field produced by a single elementary charge located at a distance of ~ 150 nm from our spin sensor with averaging for one second. By careful analysis of the electronic structure of the defect centre, we show how an applied magnetic field influences the electric field sensing properties. By this we demonstrate that diamond defect centre spins can be switched between electric and magnetic field sensing modes and identify suitable parameter ranges for both detector schemes. By combining magnetic and electric field sensitivity, nanoscale detection and ambient operation our study opens up new frontiers in imaging and sensing applications ranging from material science to bioimaging

    The evaluation of a health education campaign on the use of leave from work during pregnancy

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    <p>Abstract</p> <p>Background</p> <p>The Italian Protective Maternity Legislation allows a woman to apply for early maternity leave from work during pregnancy if she is affected by health problems (option A) or if her working conditions are incompatible with pregnancy (option B). A community based health education program, implemented between 1995 to 1998 in North Eastern Italy, provided counseling (by a team of gynecologists, pediatricians, geneticists, psychologists and occupational physicians), and an information leaflet detailing the risks during pregnancy and the governmental benefits available to expectant mothers. This leaflet was distributed to women who were under occupational medical surveillance and to women attending any healthcare office and outpatient department and was also mailed to women working at home as shoemakers.</p> <p>The effectiveness of this intervention has been evaluated in this investigation using an evidence based approach.</p> <p>Methods</p> <p>A quasi-experimental design was adopted, applying several outcome measurements before (1989 to 1994) and after (1999 to 2005) the intervention. The outcome (ratio B/A) is the number of women receiving approval for B (circumstance where the pregnant woman is employed to undertake activities forbidden under the Article 7 of Law 151/2001, and it is impossible to change her duties) to those receiving approval for A (risky pregnancy due to personal medical conditions, Article 17 of the same Law). A linear regression coefficient (for B/A against years) was obtained separately for time periods "before" (1989-94) and "after" (1999-2005) the intervention program. The two regression coefficients were compared using a t-test.</p> <p>Results</p> <p>The trend over-time for the ratio B/A was steady before the initial intervention (y = 0.008x - 16.087; t = 2.09; p > 0.05) then increased considerably (y = 0.0426x - 84.89; t = 19.55; p < 0.001) in coincidence with the start of the education campaign. There was a significant difference between the two regression coefficients (t = 7.58; p < 0.001).</p> <p>Conclusion</p> <p>From a bureaucratic perspective Option B is far more complicated than A. In fact it implies an active approach involving an arrangement between the claimant and the employer, who has to certify to the relevant Authority that the woman's working conditions are incompatible with pregnancy. The increasing number of women availing of option B, as recommended, therefore suggests the suitability of such educational campaign(s).</p
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