31 research outputs found

    Tracking virus outbreaks in the twenty-first century

    Get PDF
    Emerging viruses have the potential to impose substantial mortality, morbidity and economic burdens on human populations. Tracking the spread of infectious diseases to assist in their control has traditionally relied on the analysis of case data gathered as the outbreak proceeds. Here, we describe how many of the key questions in infectious disease epidemiology, from the initial detection and characterization of outbreak viruses, to transmission chain tracking and outbreak mapping, can now be much more accurately addressed using recent advances in virus sequencing and phylogenetics. We highlight the utility of this approach with the hypothetical outbreak of an unknown pathogen, 'Disease X', suggested by the World Health Organization to be a potential cause of a future major epidemic. We also outline the requirements and challenges, including the need for flexible platforms that generate sequence data in real-time, and for these data to be shared as widely and openly as possible

    Impact of ionomer content on proton exchange membrane fuel cell performance

    Get PDF
    The effect of Nafion ionomer content on performance of a proton exchange membrane (PEM) fuel cell operated with home-made anodic and cathodic electrodes fabricated from a novel metal organic framework (MOF) derived Pt-based electrocatalyst was investigated via numerical simulation and experimental measurement. First, the parameter sensitivity analysis was performed to identify the most influential parameters of the model. Then, these parameters were calibrated for different fuel cell designs investigated in the current study by employing the corresponding experimental data. Afterwards, the calibrated model was used to examine the impact of Nafion content in the catalyst layer of home-made electrodes. Finally, the qualitative trend predicted by this model was experimentally surveyed by varying the Nafion content between 10–50 wt.% in the catalyst layer of home-made electrodes. At the anode side, the performance of home-made electrode in a PEM fuel cell demonstrated small dependency on Nafion content. For the cathodic home-made electrode, Nafion content was found to affect the PEM fuel cell performance more strongly. Although the model could correctly capture the impact of Nafion content on calculated polarization curves, the model predicted optimum values significantly deviate from the experimental results. This was related to the several simplifications made during model development

    Articular Cartilage Assessment Using Ultrashort Echo Time MRI: A Review

    No full text
    Articular cartilage is a major component of the human knee joint which may be affected by a variety of degenerative mechanisms associated with joint pathologies and/or the aging process. Ultrashort echo time (UTE) sequences with a TE less than 100 µs are capable of detecting signals from both fast- and slow-relaxing water protons in cartilage. This allows comprehensive evaluation of all the cartilage layers, especially for the short T2 layers which include the deep and calcified zones. Several ultrashort echo time (UTE) techniques have recently been developed for both morphological imaging and quantitative cartilage assessment. This review article summarizes the current catalog techniques based on UTE Magnetic Resonance Imaging (MRI) that have been utilized for such purposes in the human knee joint, such as T1, T2∗ , T1ρ, magnetization transfer (MT), double echo steady state (DESS), quantitative susceptibility mapping (QSM) and inversion recovery (IR). The contrast mechanisms as well as the advantages and disadvantages of these techniques are discussed

    Spouted bed drying of skimmed milk: Multivariable optimization of the conditions to improve physicochemical properties of the dried milk

    No full text
    In the present research, the influence of the inlet parameters of a laboratory spouted bed (inlet air temperature and milk flow rate) on the physical properties (moisture content, wettability, dispersibility, particle size and density), chemical properties (protein, cholesterol, and triglyceride content) and morphology of the milk powder was evaluated and compared with properties of the commercial spray dried powder. The effect of these two inlet parameters was significant on all of the physical and chemical properties. Particle morphology of the spouted bed dried samples (flat, solid, and irregular) was entirely different from commercial spray dried milk powder (spherical, and hollow). The optimum values of the inlet air temperature and milk flow rate, calculated by RSM, were obtained 80 °C and 2.8 ml/min, respectively. The small error between properties predicted by the models and the experimental data indicated that the performed optimization was satisfactory. © 2021 Elsevier Lt

    Utility of a Newly Designed Film Holder for Premolar Bitewing Radiography

    No full text
    INTRODUCTION: Bitewing radiography is a valuable technique for assessment of proximal caries, alveolar crest and periodontal status. Technical errors during radiography result in erroneous radiographic interpretation, misdiagnosis, possible mistreatment or unnecessary exposure of patient for taking a repeat radiograph. AIM: In this study, we aimed to evaluate the efficacy of a film holder modified from the conventional one and compared it with that of conventional film holder. MATERIALS AND METHODS: Our study population comprised of 70 patients who were referred to the Radiology Department for bilateral premolar bitewing radiographs as requested by their attending clinician. Bitewing radiographs in each patient were taken using the newly designed holder in one side and the conventional holder in the other side. The acceptability of the two holders from the perspectives of the technician and patients was determined using a 0-20 point scale. The frequency of overlap and film positioning errors was calculated for each method. RESULTS: The conventional holder had greater acceptability among patients compared to the newly designed holder (mean score of 16.59 versus 13.37). From the technicians' point of view, the newly designed holder was superior to the conventional holder (mean score of 17.33 versus 16.44). The frequency of overlap was lower using the newly designed holder (p<0.001) and it allowed more accurate film positioning (p=0.005). CONCLUSION: The newly designed holder may facilitate the process of radiography for technicians and may be associated with less frequency of radiographic errors compared to the conventional holder

    Accelerated Quantitative 3D UTE-Cones Imaging Using Compressed Sensing

    No full text
    In this study, the feasibility of accelerated quantitative Ultrashort Echo Time Cones (qUTE-Cones) imaging with compressed sensing (CS) reconstruction is investigated. qUTE-Cones sequences for variable flip angle-based UTE T1 mapping, UTE adiabatic T1&rho; mapping, and UTE quantitative magnetization transfer modeling of macromolecular fraction (MMF) were implemented on a clinical 3T MR system. Twenty healthy volunteers were recruited and underwent whole-knee MRI using qUTE-Cones sequences. The k-space data were retrospectively undersampled with different undersampling rates. The undersampled qUTE-Cones data were reconstructed using both zero-filling and CS reconstruction. Using CS-reconstructed UTE images, various parameters were estimated in 10 different regions of interests (ROIs) in tendons, ligaments, menisci, and cartilage. Structural similarity, percentage error, and Pearson&rsquo;s correlation were calculated to assess the performance. Dramatically reduced streaking artifacts and improved SSIM were observed in UTE images from CS reconstruction. A mean SSIM of ~0.90 was achieved for all CS-reconstructed images. Percentage errors between fully sampled and undersampled CS-reconstructed images were below 5% for up to 50% undersampling (i.e., 2&times; acceleration). High linear correlation was observed (&gt;0.95) for all qUTE parameters estimated in all subjects. CS-based reconstruction combined with efficient Cones trajectory is expected to achieve a clinically feasible scan time for qUTE imaging
    corecore