464 research outputs found

    The Meaning and Significance of the Gorshkov Articles

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    The Gorshkov series represents 11 articles which appeared in Morskoy Sbornik, the Soviet Naval Digest, from 1972 into 1973. The entire series was entitled Navies in War and Peace and consisted of 50,000 words of sustained, forceful prose. The author of the work is Adm. Sergey Georgievich Gorshkov who, since 1956, has been the Commander in Chief of the Soviet Navy and who has reputedly enjoyed the trust and confidence of both Khrushchev and Brezhnev

    Structures of Mycobacterium tuberculosis folylpolyglutamate synthase complexed with ADP and AMPPCP

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    Crystal structures of M. tuberculosis folylpolyglutamate synthetase complexed with two nucleotides have been determined at 2.0 and 2.3 Å resolution, revealing an active-site loop movement and associated changes that influence substrate binding

    Anomalous scattering analysis of Agrobacterium radiobacter phosphotriesterase: the prominent role of iron in the heterobinuclear active site

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    Bacterial phosphotriesterases are binuclear metalloproteins from which the catalytic mechanism has been studied with a variety of techniques, principally using active sites reconstituted in vitro from apo-enzymes. Here, atomic absorption spectroscopy and anomalous X-ray scattering and have been used to determine the identity of the metals incorporated into the active site in vivo. We have recombinantly expressed the phosphotriesterase from Agrobacterium radiobacter (OpdA) in Escherichia coli grown in medium supplemented with 1 mM CoCl2, and in unsupplemented medium. Anomalous scattering data, collected from a single crystal at the Fe-K, Co-K and Zn-K edges, indicate that iron and cobalt are the primary constituents of the two metal binding sites in the catalytic centre ( and ), in protein expressed in E. coli grown in supplemented medium. Comparison to OpdA expressed in unsupplemented medium demonstrates that the cobalt present in the supplemented medium replaced zinc at the -position of the active site, which results in an increase in the catalytic efficiency of the enzyme. These results suggest an essential role for iron in the catalytic mechanism of bacterial phosphotriesterases, and that they are natively heterobinuclear iron-zinc enzymes

    Designer diatom episomes delivered by bacterial conjugation.

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    Eukaryotic microalgae hold great promise for the bioproduction of fuels and higher value chemicals. However, compared with model genetic organisms such as Escherichia coli and Saccharomyces cerevisiae, characterization of the complex biology and biochemistry of algae and strain improvement has been hampered by the inefficient genetic tools. To date, many algal species are transformable only via particle bombardment, and the introduced DNA is integrated randomly into the nuclear genome. Here we describe the first nuclear episomal vector for diatoms and a plasmid delivery method via conjugation from Escherichia coli to the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. We identify a yeast-derived sequence that enables stable episome replication in these diatoms even in the absence of antibiotic selection and show that episomes are maintained as closed circles at copy number equivalent to native chromosomes. This highly efficient genetic system facilitates high-throughput functional characterization of algal genes and accelerates molecular phytoplankton research

    Yield of colorectal cancer at colonoscopy according to faecal haemoglobin concentration in symptomatic patients referred from primary care

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    Background: Lower gastrointestinal (GI) symptoms are poor predictors of colorectal cancer (CRC). This study examined the diagnostic yield of colonoscopy by faecal haemoglobin concentration (f‐Hb) in symptomatic patients assessed in primary care by faecal immunochemical testing (FIT). Methods: In three Scottish NHS Boards, FIT kits (HM‐JACKarc, Hitachi Chemical Diagnostics Systems Co., Ltd, Tokyo, Japan) were used by GPs to guide referrals for patients with lower GI symptoms (lab data studied for 12 months from December 2015 onward in Tayside, 18 months from June 2018 onward in Fife, and 5 months from September 2018 onward in Greater Glasgow and Clyde). CRC cases diagnosed at colonoscopy were ascertained from colonoscopy and pathology records. Results: 4841 symptomatic patients who underwent colonoscopy after FIT submission were included. Of 2166 patients (44.7%) with f‐Hb <10 µg Hb/g faeces (µg/g), 14 (0.6%) were diagnosed with CRC, with a number needed to scope (NNS) of 155. Of 2675 patients (55.3%) with f‐Hb ≥10 µg/g, 252 were diagnosed with CRC (9.4%) with a NNS of 11. Of 705 patients with f‐Hb ≥400 µg/g, 158 (22.4%) were diagnosed with CRC with a NNS of 5. Over half of those diagnosed with CRC with f‐Hb <10 µg/g had co‐existing anaemia. Conclusions: Symptomatic patients with f‐Hb ≥10 µg/g should undergo further investigation for CRC, while higher f‐Hb could be used to triage its urgency during the COVID‐19 recovery phase. Patients with f‐Hb <10 µg/g, without anaemia, are very unlikely to be diagnosed with CRC and the majority need no further investigation

    Remote access to crystallography beamlines at SSRL: novel tools for training, education and collaboration

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    The ultimate goal of synchrotron data collection is to obtain the best possible data from the best available crystals, and the combination of automation and remote access at Stanford Synchrotron Radiation Lightsource (SSRL) has revolutionized the way in which scientists achieve this goal. This has also seen a change in the way novice crystallographers are trained in the use of the beamlines, and a wide range of remote tools and hands-on workshops are now offered by SSRL to facilitate the education of the next generation of protein crystallographers

    From ‘shallow’ to ‘deep’ policing:‘crash-for-cash’ insurance fraud investigation in England and Wales and the need for greater regulation

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    The policing of insurance fraud has traditionally been dealt with beyond the criminal justice system as a private matter between the claimant and the insurer with only a few iconic cases referred to the criminal justice system each year. The growth of insurance fraud, particularly ‘crash-for-cash’ fraud, and the disinterest of the police, has led to a change in the response of the insurance industry. This paper will argue that this response can be characterised as a shift from the traditional ‘shallow’ to a ‘deeper’ form of policing which sees greater focus upon criminal and quasi-criminal outcomes. This paper explores some of the private and innovative methods the industry has developed and illustrates what greater private criminal investigation might look like at a time when police privatisation has become a higher profile issue. The paper argues the shift to ‘deeper’ policing necessitates greater regulation of the private investigation of crime and outlines a number of proposals to address this gap which require further consideration and debate

    The use of insecticide treated nets by age: implications for universal coverage in Africa

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    BACKGROUND: The scaling of malaria control to achieve universal coverage requires a better understanding of the population sub-groups that are least protected and provide barriers to interrupted transmission. Here we examine the age pattern of use of insecticide treated nets (ITNs) in Africa in relation to biological vulnerabilities and the implications for future prospects for universal coverage. METHODS: Recent national household survey data for 18 malaria endemic countries in Africa were assembled to identify information on use of ITNs by age and sex. Age-structured medium variant projected population estimates for the mid-point year of the earliest and most recent national surveys were derived to compute the population by age protected by ITNs. RESULTS: All surveys were undertaken between 2005 and 2009, either as demographic health surveys (n = 12) or malaria indicator surveys (n = 6). Countries were categorized into three ITN use groups: or =20% and projected population estimates for the mid-point year of 2007 were computed. In general, the pattern of overall ITNs use with age was similar by country and across the three country groups with ITNs use initially high among children <5 years of age, sharply declining among the population aged 5-19 years, before rising again across the ages 20-44 years and finally decreasing gradually in older ages. For all groups of countries, the highest proportion of the population not protected by ITNs (38% - 42%) was among those aged 5-19 years. CONCLUSION: In malaria-endemic Africa, school-aged children are the least protected with ITNs but represent the greatest reservoir of infections. With increasing school enrollment rates, school-delivery of ITNs should be considered as an approach to reach universal ITNs coverage and improve the likelihood of impacting upon parasite transmission
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