1,130,246 research outputs found

    An assessment of the screening method to evaluate vaccine effectiveness: the case of 7-valent pneumococcal conjugate vaccine in the United States.

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    The screening method, which employs readily available data, is an inexpensive and quick means of estimating vaccine effectiveness (VE). We compared estimates of effectiveness of heptavalent pneumococcal conjugate vaccine (PCV7) against invasive pneumococcal disease (IPD) using the screening and case-control methods. Cases were children aged 19-35 months with pneumococcus isolated from normally sterile sites residing in Active Bacterial Core surveillance areas in the United States. Case-control VE was estimated for 2001-2004 by comparing the odds of vaccination among cases and community controls. Screening-method VE for 2001-2009 was estimated by comparing the proportion of cases vaccinated to National Immunization Survey-derived coverage among the general population. To evaluate the plausibility of screening-method VE findings, we estimated attack rates among vaccinated and unvaccinated persons. We identified 1,154 children with IPD. Annual population PCV7 coverage with ≄1 dose increased from 38% to 97%. Case-control VE for ≄1 dose was estimated as 75% against all-serotype IPD (annual range: 35-83%) and 91% for PCV7-type IPD (annual range: 65-100%). By the screening method, the overall VE was 86% for ≄1 dose (annual range: -240-70%) against all-serotype IPD and 94% (annual range: 62-97%) against PCV7-type IPD. As cases of PCV7-type IPD declined during 2001-2005, estimated attack rates for all-serotype IPD among vaccinated and unvaccinated individuals became less consistent than what would be expected with the estimated effectiveness of PCV7. The screening method yields estimates of VE that are highly dependent on the time period during which it is used and the choice of outcome. The method should be used cautiously to evaluate VE of PCVs

    Screening method improves performance of nickel-cadmium batteries

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    Weight of single plate in batch is used as criterion for selecting those plates with uniform, high ampere hour capacity. When substrate and plaque weights are uniform, observed current capacity differences are dependent on quantity of active material in plaque

    Automation potential of a new, rapid, microscopy based method for screening drug-polymer solubility

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    For the pharmaceutical industry, the preformulation screening of the compatibility of drug and polymeric excipients can often be time-consuming because of the use of trial-and-error approaches. This is also the case for selecting highly effective polymeric excipients for forming molecular dispersions in order to improve the dissolution and subsequent bio-availability of a poorly soluble drug. Previously, we developed a new thermal imaging-based rapid screening method, thermal analysis by structure characterization (TASC), which can rapidly detect the melting point depression of a crystalline drug in the presence of a polymeric material. In this study, we used melting point depression as an indicator of drug solubility in a polymer and further explored the potential of using the TASC method to rapidly screen and identify polymers in which a drug is likely to have high solubility. Here, we used a data bank of 5 model drugs and 10 different pharmaceutical grade polymers to validate the screening potential of TASC. The data indicated that TASC could provide significant improvement in the screening speed and reduce the materials used without compromising the sensitivity of detection. It should be highlighted that the current method is a screening method rather than a method that provides absolute measurement of the degree of solubility of a drug in a polymer. The results of this study confirmed that the TASC results of each drug-polymer pair could be used in data matrices to indicate the presence of significant interaction and solubility of the drug in the polymer. This forms the foundation for automating the screening process using artificial intelligence

    Colour Charges and the Anti-Screening Contribution to the Interquark Potential

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    Asymptotic freedom arises from the dominance of anti-screening over screening in non-abelian gauge theories. In this paper we will present a simple and physically appealing derivation of the anti-screening contribution to the interquark potential. Our method allows us to identify the dominant gluonic distribution around static quarks. Extensions are discussed.Comment: 7 pages, LaTe

    Determination of screened Coulomb repulsion energies in organic molecular crystals: A real space approach

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    We present a general method for determining screened Coulomb parameters in molecular assemblies, in particular organic molecular crystals. This allows us to calculate the interaction parameters used in a generalized Hubbard model description of correlated organic materials. In such a model only the electrons in levels close to the Fermi level are included explicitly, while the effect of all other electrons is included as a renormalization of the model parameters. For the Coulomb integrals this renormalization is mainly due to screening. For molecular materials we can split the screening into intra- and inter-molecular screening. Here we demonstrate how the inter-molecular screening can be calculated by modeling the molecules by distributed point-polarizabilities and solving the resulting self-consistent electrostatic screening problem in real space. For the example of the quasi one-dimensional molecular metal TTF-TCNQ we demonstrate that the method gives remarkably accurate results.Comment: Submitted to Special Issue - ISCOM 2009 - Physica B Condensed Matte

    The cost-utility of telemedicine to screen for diabetic retinopathy in India.

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    PURPOSE: To assess the cost-effectiveness of a telemedicine diabetic retinopathy (DR) screening program in rural Southern India that conducts 1-off screening camps (i.e., screening offered once) in villages and to assess the incremental cost-effectiveness ratios of different screening intervals. DESIGN: A cost-utility analysis using a Markov model. PARTICIPANTS: A hypothetical cohort of 1000 rural diabetic patients aged 40 years who had not been previously screened for DR and who were followed over a 25-year period in Chennai, India. METHODS: We interviewed 249 people with diabetes using the time trade-off method to estimate utility values associated with DR. Patient and provider costs of telemedicine screening and hospital-based DR treatment were estimated through interviews with 100 diabetic patients, sampled when attending screening in rural camps (n = 50) or treatment at the base hospital in Chennai (n = 50), and with program and hospital managers. The sensitivity and specificity of the DR screening test were assessed in comparison with diagnosis using a gold standard method for 346 diabetic patients. Other model parameters were derived from the literature. A Markov model was developed in TreeAge Pro 2009 (TreeAge Software Inc, Williamstown, MA) using these data. MAIN OUTCOME MEASURES: Cost per quality-adjusted life-year (QALY) gained from the current teleophthalmology program of 1-off screening in comparison with no screening program and the cost-utility of this program at different screening intervals. RESULTS: By using the World Health Organization threshold of cost-effectiveness, the current rural teleophthalmology program was cost-effective (1320perQALY)comparedwithnoscreeningfromahealthproviderperspective.Screeningintervalsofuptoafrequencyofscreeningevery2yearsalsowerecost−effective,butannualscreeningwasnot(>1320 per QALY) compared with no screening from a health provider perspective. Screening intervals of up to a frequency of screening every 2 years also were cost-effective, but annual screening was not (>3183 per QALY). From a societal perspective, telescreening up to a frequency of once every 5 years was cost-effective, but not more frequently. CONCLUSIONS: From a health provider perspective, a 1-off DR telescreening program is cost-effective compared with no screening in this rural Indian setting. Increasing the frequency of screening up to 2 years also is cost-effective. The results are dependent on the administrative costs of establishing and maintaining screening at regular intervals and on achieving sufficient coverage

    High-Throughput Screening of Acyl-CoA Thioesterase I Mutants Using a Fluid Array Platform

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    Screening target microorganisms from a mutated recombinant library plays a crucial role in advancing synthetic biology and metabolic engineering. However, conventional screening tools have several limitations regarding throughput, cost, and labor. Here, we used the fluid array platform to conduct high-throughput screening (HTS) that identified Escherichia coli ???TesA thioesterase mutants producing elevated yields of free fatty acids (FFAs) from a large (106) mutant library. A growth-based screening method using a TetA-RFP fusion sensing mechanism and a reporter-based screening method using high-level FFA producing mutants were employed to identify these mutants via HTS. The platform was able to cover >95% of the mutation library, and it screened target cells from many arrays of the fluid array platform so that a post-analysis could be conducted by gas chromatography. The ???TesA mutation of each isolated mutant showing improved FFA production in E. coli was characterized, and its enhanced FFA production capability was confirmed
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