1,622 research outputs found

    Optimisation of the Schizosaccharomyces pombe urg1 expression system

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    The ability to study protein function in vivo often relies on systems that regulate the presence and absence of the protein of interest. Two limitations for previously described transcriptional control systems that are used to regulate protein expression in fission yeast are: the time taken for inducing conditions to initiate transcription and the ability to achieve very low basal transcription in the "OFF-state". In previous work, we described a Cre recombination-mediated system that allows the rapid and efficient regulation of any gene of interest by the urg1 promoter, which has a dynamic range of approximately 75-fold and which is induced within 30-60 minutes of uracil addition. In this report we describe easy-to-use and versatile modules that can be exploited to significantly tune down P urg1 "OFF-levels" while maintaining an equivalent dynamic range. We also provide plasmids and tools for combining P urg1 transcriptional control with the auxin degron tag to help maintain a null-like phenotype. We demonstrate the utility of this system by improved regulation of HO-dependent site-specific DSB formation, by the regulation Rtf1-dependent replication fork arrest and by controlling Rhp18(Rad18)-dependent post replication repair

    ESAT-6/CFP10 Skin Test Predicts Disease in M. tuberculosis-Infected Guinea Pigs

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    Background: Targeted preventive chemotherapy of individuals with progressive subclinical (incipient) disease before it becomes contagious would break the chain of tuberculosis transmission in high endemic regions. We have studied the ability of a skin test response to ESAT-6 and CFP10 (E6/C10) to predict later development of tuberculosis disease in the guinea pig model. Methods and Findings: Guinea pigs, either vaccinated with BCG or unvaccinated, were infected with a low dose of Mycobacterium tuberculosis by the aerosol route and the development of delayed type hypersensitivity responses to E6/C10 and to purified protein derivative (PPD) were followed until the onset of clinical disease. We demonstrated a negative correlation between the size of the skin test response and the time to the onset of clinical disease; a large E6/C10 skin test response correlated to a shorter survival time post skin testing, while a small E6/C10 skin test reaction correlated with a longer survival time (r = 20.6 and P,0.0001). No correlation was found using PPD. Conclusions: Our data suggest that it may be possible to develop a prognostic skin test based on E6/C10 that will allow the identification of individuals with incipient disease, who have the highest risk of developing active tuberculosis in the near future

    Cumulative incidence of entry into out-of-home care:Changes over time in Denmark and England

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    Policies and thresholds vary for placing children into out-of-home care (OHC) at different ages. Evidence is lacking that quantifies the risk of entering OHC by age, and how this varies over time and between countries. We determined the age-specific cumulative incidence of ever entering OHC during childhood in Denmark and in eight local authorities in England. We used administrative data for any form of OHC (except respite care) provided by children's social services in Denmark and England from 1992 to 2008. Using life tables and national population estimates, we calculated the cumulative incidence of entry into OHC by year of age for cohorts born in 1992–1994 through to 2006–2008. The cumulative incidence of entry into OHC decreased over time in Denmark and increased in England at all ages. Cumulative incidence of OHC in the first year of life was similar in Denmark and England for infants born in 1992–1994 (Denmark 2.83/1,000, England 2.89/1,000), but infants born in 2007–2008 were nearly three times as likely to enter OHC before their first birthday in England (4.50/1,000) than in Denmark (1.61/1,000). Entry into OHC during adolescence was more common in Denmark than in England so that by 16 years old the cumulative incidence of ever entering OHC during childhood was twice as high in Denmark (33.83/1,000) as in England (15.62/1,000). Diverging trends over time in the use of OHC in Denmark and England are likely to reflect changing policies in the two countries

    A comparison of hospital readmission rates between two general physicians with different outpatient review practices

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    BACKGROUND: There has been a relentless increase in emergency medical admissions in the UK over recent years. Many of these patients suffer with chronic conditions requiring continuing medical attention. We wished to determine whether conventional outpatient clinic follow up after discharge has any impact on the rate of readmission to hospital. METHODS: Two consultant general physicians with the same patient case-mix but markedly different outpatient follow-up practice were chosen. Of 1203 patients discharged, one consultant saw twice as many patients in the follow-up clinic than the other (Dr A 9.8% v Dr B 19.6%). The readmission rate in the twelve months following discharge was compared in a retrospective analysis of hospital activity data. Due to the specialisation of the admitting system, patients mainly had cardiovascular or cerebrovascular disease or had taken an overdose. Few had respiratory or infectious diseases. Outpatient follow-up was focussed on patients with cardiac disease. RESULTS: Risk of readmission increased significantly with age and length of stay of the original episode and was less for digestive system and musculo-skeletal disorders. 28.7% of patients discharged by Dr A and 31.5 % of those discharged by Dr B were readmitted at least once. Relative readmission risk was not significantly different between the consultants and there was no difference in the length of stay of readmissions. CONCLUSIONS: Increasing the proportion of patients with this age- and case-mix who are followed up in a hospital general medical outpatient clinic is unlikely to reduce the demand for acute hospital beds

    Ab-initio Quantum Enhanced Optical Phase Estimation Using Real-time Feedback Control

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    Optical phase estimation is a vital measurement primitive that is used to perform accurate measurements of various physical quantities like length, velocity and displacements. The precision of such measurements can be largely enhanced by the use of entangled or squeezed states of light as demonstrated in a variety of different optical systems. Most of these accounts however deal with the measurement of a very small shift of an already known phase, which is in stark contrast to ab-initio phase estimation where the initial phase is unknown. Here we report on the realization of a quantum enhanced and fully deterministic phase estimation protocol based on real-time feedback control. Using robust squeezed states of light combined with a real-time Bayesian estimation feedback algorithm, we demonstrate deterministic phase estimation with a precision beyond the quantum shot noise limit. The demonstrated protocol opens up new opportunities for quantum microscopy, quantum metrology and quantum information processing.Comment: 5 figure
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