359 research outputs found

    Chronic osteomyelitis: what the surgeon needs to know

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    Chronic osteomyelitis represents a progressive inflammatory process caused by pathogens, resulting in bone destruction and sequestrum formation. It may present with periods of quiescence of variable duration, whereas its occurrence, type, severity and prognosis is multifactorial. The ‘gold standard’ for the diagnosis of chronic osteomyelitis is the presence of positive bone cultures and histopathologic examination of the bone. Its management remains challenging to the treating physician, with a multidisciplinary approach involving radiologists, microbiologists with expertise in infectious diseases, orthopaedic surgeons and plastic surgeons. Treatment should be tailored to each patient according the severity and duration of symptoms, as well as to the clinical and radiological response to treatment. A combined antimicrobial and surgical treatment should be considered in all cases, including appropriate dead space management and subsequent reconstruction. Relapse can occur, even following an apparently successful treatment, which has a major impact on the quality of life of patients and is a substantial financial burden to any healthcare system

    Case History of an Uplift Problem

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    Deformation and related stability problems of dikes in the western parts of Holland were for many years ascribed to creep and excess pore water pressures only. However in the spring of 1988 during a high water period in the river Rhine the so called uplift mechanism was for the first time measured in practice. It was then recognised that in some cases the problems have been caused by the uplift phenomenon. For a few years the pore water pressures and the deformations were observed in a test site. With the results of the observations a procedure was formulated for design and reconstruction

    Sustainability Action Tracker

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    The Center for Sustainability at Santa Clara University is actively looking for ways to involve students in sustainable actions and accountability. With our help, they would like to create a site where students and faculty may track their sustainable behavior. This site will provide users with all the information they need to live a sustainable life, and include milestones in the form of progress bars and badges. The Center for Sustainability will be able to collect the data from this site to evaluate the progress of our university as well as the success of the site. Our motivation for this project is the urgency around raising awareness about the critical state of the environment. This project is necessary for the University to track their progress with their mission of creating a ’more just and sustainable world’

    Shared Annotations: Attitudes and Behaviors of Scholars

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    Annotations, in the form of markings and comments on the text, are often part of scholarly work. Digital platforms increasingly allow these annotations to be shared in group and public environments. To explore scholars' current behavior and attitudes toward shared annotations, semi-structured interviews with 11 doctoral students in the life sciences were conducted. The findings suggest that socio-cognitive processes are integral to scholars' creation and use of shared annotations. This paper discusses common themes from the findings and their implications for effective design of annotation systems supporting scholarly communication

    The Probability of Failure of an in Stages Constructed Embankment on Soft Soil

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    During construction of the first one of a twin dam in the Oosterschelde basin several instabilities occurred. Design of the construction plan of the dam was based on classical methods of analysis of stability and usually applied safety criteria. Back analysis of the failures consisted of a probabilistic analysis, indicating high overall probabilities of failure, and FEM analysis, indicating areas of large plastic deformation of the subsoil, caused by the steep setup of the sandfill in \u27the initial construction stage, resulting in too concentrated surcharge. Based on these results, it was decided to apply these methods of analysis from the beginning in the design of the construction plan for the second dam. This plan has successfully been carried out

    RAPID THERMOCYCLER SYSTEM FOR RAPID AMPLIFICATION OF NUCLEIC ACIDS AND RELATED METHODS

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    A thermo cycling device and method of operating a thermocycler instrument, the instrument including a sample holder, at least one thermal cycling element, and at least one first and second temperature sensors, for causing the sample holder containing the at least one sample to undergo polymerase chain reaction amplification by repeated cycling between at least a denaturation heating stage and an aunealing cooling stage. The first temperature corresponding with the temperature of the sample holder is monitored using the at least one first temperature sensor, and a second temperature corresponding with the temperature external of the sample holder is monitored using the at least one second temperature sensor. Based upon the first temperature and the second temperature, the power that is delivered to the at least one thermal cycling element of the instrument is dynamically controlled

    Gene synthesis by integrated polymerase chain assembly and PCR amplification using a high-speed thermocycler

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    Polymerase chain assembly (PCA) is a technique used to synthesize genes ranging from a few hundred base pairs to many kilobase pairs in length. In traditional PCA, equimolar concentrations of single stranded DNA oligonucleotides are repeatedly hybridized and extended by a polymerase enzyme into longer dsDNA constructs, with relatively few full-length sequences being assembled. Thus, traditional PCA is followed by a second primer-mediated PCR reaction to amplify the desired full-length sequence to useful, detectable quantities. Integration of assembly and primer-mediated amplification steps into a single reaction using a high-speed thermocycler is shown to produce similar results. For the integrated technique, the effects of oligo concentration, primer concentration, and number of oligonucleotides are explored. The technique is successfully demonstrated for the synthesis of two genes encoding EPCR-1 (653 bp) and pUC19 β-lactamase (929 bp) in under 20 min. However, rapid integrated PCA–PCR was found to be problematic when attempted with the TM-1 gene (1509 bp). Partial oligonucleotide sets of TM-1 could be assembled and amplified simultaneously, indicating that the technique may be limited to a maximum number of oligonucleotides due to competitive annealing and competition for primers

    Gene synthesis by integrated polymerase chain assembly and PCR amplification using a high-speed thermocycler

    Get PDF
    Polymerase chain assembly (PCA) is a technique used to synthesize genes ranging from a few hundred base pairs to many kilobase pairs in length. In traditional PCA, equimolar concentrations of single stranded DNA oligonucleotides are repeatedly hybridized and extended by a polymerase enzyme into longer dsDNA constructs, with relatively few full-length sequences being assembled. Thus, traditional PCA is followed by a second primer-mediated PCR reaction to amplify the desired full-length sequence to useful, detectable quantities. Integration of assembly and primer-mediated amplification steps into a single reaction using a high-speed thermocycler is shown to produce similar results. For the integrated technique, the effects of oligo concentration, primer concentration, and number of oligonucleotides are explored. The technique is successfully demonstrated for the synthesis of two genes encoding EPCR-1 (653 bp) and pUC19 β-lactamase (929 bp) in under 20 min. However, rapid integrated PCA–PCR was found to be problematic when attempted with the TM-1 gene (1509 bp). Partial oligonucleotide sets of TM-1 could be assembled and amplified simultaneously, indicating that the technique may be limited to a maximum number of oligonucleotides due to competitive annealing and competition for primers

    Experimental Validation of a Fundamental Model for PCR Efficiency

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    Recently a theoretical analysis of PCR efficiency has been published by Booth et al., (2010). The PCR yield is the product of three efficiencies: (i) the annealing efficiency is the fraction of templates that form binary complexes with primers during annealing, (ii)the polymerase binding efficiency is the fraction of binary complexes that bind to polymerase to form ternary complexes and (iii)the elongation efficiency is the fraction of ternary complexes that extend fully. Yield is controlled by the smallest of the three efficiencies and control could shift from one type of efficiency to another over the course of a PCR experiment. Experiments have been designed that are specifically controlled by each one of the efficiencies and the results are consistent with the mathematical model. The experimental data has also been used to quantify six key parameters of the theoretical model. An important application of the fully characterized model is to calculate initial template concentration from real-time PCR data. Given the PCR protocol, the midpoint cycle number (where the template concentration is half that of the final concentration) can be theoretically determined and graphed for a variety of initial DNA concentrations. Real-time results can be used to calculate the midpoint cycle number and consequently the initial DNA concentration, using this graph. The application becomes particularly simple if a conservative PCR protocol is followed where only the annealing efficiency is controlling
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