361 research outputs found

    A preliminary study of the Soviet civil space program. Volume 1: Organization and Operations

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    The organization, planning, and personnel is focused of Soviet space, advantage is taken of glasnost and improved foreign relations to explore a hitherto obscure subject. The way in which the civil space program obtains approval and funding is altered. Missions must be approved before the Supreme Soviet, and public opinion is beginning to play a greater role in the legislature's budget decision. The Soviet civil space program remains a collection of disparate elements, not unified by any national, centralized space agency. An attempt was made to catalog and delineate the relationships between the components proves helpful. There is little or no coordination of independent associations' efforts, and the planning process relied on previously to set priorities and allocate resources appears to be currently inoperative or in a state of flux. The civil space program is moving in new directions: toward budget tautness, more international interactions, an emphasis on civilian over military applications, commercialization, and fiscal accountability. This study is a snapshot of a dynamic subject, but hopefully on which has highlighted the critical elements to track

    Novel food-safe spin-lattice relaxation time calibration samples for use in magnetic resonance sensor development

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    Magnetic Resonance (MR) sensors are an area of increasing interest for the measurement and monitoring of material properties. There are two relaxation times associated with samples that can be measured with MR sensors: The spin-lattice and spin-spin relaxations. When developing new sensors, it is desirable to have a series of standards by which instruments can be assessed. The standard calibration materials available typically comprise different concentrations of Nickel Sulphate, which is carcinogenic and toxic. In this work, we report the use of solutions containing full fat milk powder as a safe and inexpensive material that shortens the longitudinal relaxation time of water over a wide range of values. We demonstrate that concentrations in distilled water from 5% W/V to 64% W/V give T1 values from 1.7 s down to 469 ms respectively in a 1.5T clinical MRI, while within an MR sensor, these times were from 1.6 s down to 431 ms. In addition, both systems have the same exponential coefficient (-0.022*concentration) that demonstrates the effectiveness of the NMR sensor in comparison to the clinical MRI

    Redox‐active hybrid polyoxometalate‐stabilised gold nanoparticles

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    We report the design and preparation of multifunctional hybrid nanomaterials through the stabilization of gold nanoparticles with thiol‐functionalised hybrid organic–inorganic polyoxometalates (POMs). The covalent attachment of the hybrid POM forms new nanocomposites that are stable at temperatures and pH values which destroy analogous electrostatically functionalised nanocomposites. Photoelectrochemical analysis revealed the unique photochemical and redox properties of these systems

    Legionella pneumophila strain 130b possesses a unique combination of type IV secretion systems and novel Dot/Icm secretion system effector proteins

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    Legionella pneumophila is a ubiquitous inhabitant of environmental water reservoirs. The bacteria infect a wide variety of protozoa and, after accidental inhalation, human alveolar macrophages, which can lead to severe pneumonia. The capability to thrive in phagocytic hosts is dependent on the Dot/Icm type IV secretion system (T4SS), which translocates multiple effector proteins into the host cell. In this study, we determined the draft genome sequence of L. pneumophila strain 130b (Wadsworth). We found that the 130b genome encodes a unique set of T4SSs, namely, the Dot/Icm T4SS, a Trb-1-like T4SS, and two Lvh T4SS gene clusters. Sequence analysis substantiated that a core set of 107 Dot/Icm T4SS effectors was conserved among the sequenced L. pneumophila strains Philadelphia-1, Lens, Paris, Corby, Alcoy, and 130b. We also identified new effector candidates and validated the translocation of 10 novel Dot/Icm T4SS effectors that are not present in L. pneumophila strain Philadelphia-1. We examined the prevalence of the new effector genes among 87 environmental and clinical L. pneumophila isolates. Five of the new effectors were identified in 34 to 62% of the isolates, while less than 15% of the strains tested positive for the other five genes. Collectively, our data show that the core set of conserved Dot/Icm T4SS effector proteins is supplemented by a variable repertoire of accessory effectors that may partly account for differences in the virulences and prevalences of particular L. pneumophila strains. Copyright Š 2010, American Society for Microbiology. All Rights Reserved

    The Lantern Vol. 12, No. 2, March 1944

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    • Save in His Own Country • Philosopher and Soldier • Soap Bubbles • Who is my Brother? • A Real Sea-Captain • Quatrain on Solitude • Wind Ahead • Jewel Song • The Sail, a Translation • They Also Serve • Ever the Twain • After the Rain • The Low-Down on Electronics • Sing, My Heart • Interlude • Unconquerable Soul • The Covenant • The Lost Warriors • Fragment • Arrivalhttps://digitalcommons.ursinus.edu/lantern/1032/thumbnail.jp

    A comparative evaluation of PDQ-Evidence

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    BACKGROUND: A strategy for minimising the time and obstacles to accessing systematic reviews of health system evidence is to collect them in a freely available database and make them easy to find through a simple ‘Google-style’ search interface. PDQ-Evidence was developed in this way. The objective of this study was to compare PDQ-Evidence to six other databases, namely Cochrane Library, EVIPNet VHL, Google Scholar, Health Systems Evidence, PubMed and Trip. METHODS: We recruited healthcare policy-makers, managers and health researchers in low-, middle- and highincome countries. Participants selected one of six pre-determined questions. They searched for a systematic review that addressed the chosen question and one question of their own in PDQ-Evidence and in two of the other six databases which they would normally have searched. We randomly allocated participants to search PDQ-Evidence first or to search the two other databases first. The primary outcomes were whether a systematic review was found and the time taken to find it. Secondary outcomes were perceived ease of use and perceived time spent searching. We asked open-ended questions about PDQ-Evidence, including likes, dislikes, challenges and suggestions for improvements. RESULTS: A total of 89 people from 21 countries completed the study; 83 were included in the primary analyses and 6 were excluded because of data errors that could not be corrected. Most participants chose PubMed and Cochrane Library as the other two databases. Participants were more likely to find a systematic review using PDQ-Evidence than using Cochrane Library or PubMed for the pre-defined questions. For their own questions, this difference was not found. Overall, it took slightly less time to find a systematic review using PDQ-Evidence. Participants perceived that it took less time, and most participants perceived PDQ-Evidence to be slightly easier to use than the two other databases. However, there were conflicting views about the design of PDQ-Evidence. CONCLUSIONS: PDQ-Evidence is at least as efficient as other databases for finding health system evidence. However, using PDQ-Evidence is not intuitive for some people

    The Metabochip, a Custom Genotyping Array for Genetic Studies of Metabolic, Cardiovascular, and Anthropometric Traits

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    PMCID: PMC3410907This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Impact of infection with human immunodeficiency virus-1 (HIV) on the risk of cancer among children in Malawi - preliminary findings

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    <p>Abstract</p> <p>Background</p> <p>The impact of infection with HIV on the risk of cancer in children is uncertain, particularly for those living in sub-Saharan Africa. In an ongoing study in a paediatric oncology centre in Malawi, children (aged ≤ 15 years) with known or suspected cancers are being recruited and tested for HIV and their mothers or carers interviewed. This study reports findings for children recruited between 2005 and 2008.</p> <p>Methods</p> <p>Only children with a cancer diagnosis were included. Odds ratios (OR) for being HIV positive were estimated for each cancer type (with adjustment for age (<5 years, ≥ 5 years) and sex) using children with other cancers and non-malignant conditions as a comparison group (excluding the known HIV-associated cancers, Kaposi sarcoma and lymphomas, as well as children with other haematological malignancies or with confirmed non-cancer diagnoses).</p> <p>Results</p> <p>Of the 586 children recruited, 541 (92%) met the inclusion criteria and 525 (97%) were tested for HIV. Overall HIV seroprevalence was 10%. Infection with HIV was associated with Kaposi sarcoma (29 cases; OR = 93.5, 95% CI 26.9 to 324.4) and with non-Burkitt, non-Hodgkin lymphoma (33 cases; OR = 4.4, 95% CI 1.1 to 17.9) but not with Burkitt lymphoma (269 cases; OR = 2.2, 95% CI 0.8 to 6.4).</p> <p>Conclusions</p> <p>In this study, only Kaposi sarcoma and non-Burkitt, non-Hodgkin lymphoma were associated with HIV infection. The endemic form of Burkitt lymphoma, which is relatively frequent in Malawi, was not significantly associated with HIV. While the relatively small numbers of children with other cancers, together with possible limitations of diagnostic testing may limit our conclusions, the findings may suggest differences in the pathogenesis of HIV-related malignancies in different parts of the world.</p
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