491 research outputs found

    Multiband monopole antenna for mobile applications

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    — In this paper, a multiband monopole antenna has been proposed for mobile applications. The monopole antenna has simple structure with a physical size of 15 cm × 7 cm. The antenna consists of monopole shape loaded by a set of folded arms with a varying length which lead to a better impedance matching result and multiband performance. The simulated results show that the proposed antenna provide multiband frequency operation of 0.8 GHz, 1.8 GHz 2.1 GHz, 2.6 GHz and 3.5 GHz which covers the range from 0 to 4 GHz. The antenna is designed to operate at sub-6 GHz which proposed as lower frequency band to deliver 5G in early stage. The designed antenna has been fabricated and measured to validate the simulated results. RF Coaxial U.FL Connector was used as the port connector. The measurement results agrees well with the simulated ones for all frequency bands

    The ongoing challenge of latent tuberculosis

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    The global health community has set itself the task of eliminating tuberculosis (TB) as a public health problem by 2050. Although progress has been made in global TB control, the current decline in incidence of 2% yr(−1) is far from the rate needed to achieve this. If we are to succeed in this endeavour, new strategies to reduce the reservoir of latently infected persons (from which new cases arise) would be advantageous. However, ascertainment of the extent and risk posed by this group is poor. The current diagnostics tests (tuberculin skin test and interferon-gamma release assays) poorly predict who will develop active disease and the therapeutic options available are not optimal for the scale of the intervention that may be required. In this article, we outline a basis for our current understanding of latent TB and highlight areas where innovation leading to development of novel diagnostic tests, drug regimens and vaccines may assist progress. We argue that the pool of individuals at high risk of progression may be significantly smaller than the 2.33 billion thought to be immune sensitized by Mycobacterium tuberculosis and that identifying and targeting this group will be an important strategy in the road to elimination

    The wonder years: what can primary school children teach us about immunity to Mycobacterium tuberculosis?

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    In high burden settings, the risk of infection with Mycobacterium tuberculosis increases throughout childhood due to cumulative exposure. However, the risk of progressing from tuberculosis (TB) infection to disease varies by age. Young children (<5 years) have high risk of disease progression following infection. The risk falls in primary school children (5 to <10 years), but rises again during puberty. TB disease phenotype also varies by age: generally, young children have intrathoracic lymph node disease or disseminated disease, while adolescents (10 to <20 years) have adult-type pulmonary disease. TB risk also exhibits a gender difference: compared to adolescent boys, adolescent girls have an earlier rise in disease progression risk and higher TB incidence until early adulthood. Understanding why primary school children, during what we term the “Wonder Years,” have low TB risk has implications for vaccine development, therapeutic interventions, and diagnostics. To understand why this group is at low risk, we need a better comprehension of why younger children and adolescents have higher risks, and why risk varies by gender. Immunological response to M. tuberculosis is central to these issues. Host response at key stages in the immunopathological interaction with M. tuberculosis influences risk and disease phenotype. Cell numbers and function change dramatically with age and sexual maturation. Young children have poorly functioning innate cells and a Th2 skew. During the “Wonder Years,” there is a lymphocyte predominance and a Th1 skew. During puberty, neutrophils become more central to host response, and CD4+ T cells increase in number. Sex hormones (dehydroepiandrosterone, adiponectin, leptin, oestradiol, progesterone, and testosterone) profoundly affect immunity. Compared to girls, boys have a stronger Th1 profile and increased numbers of CD8+ T cells and NK cells. Girls are more Th2-skewed and elicit more enhanced inflammatory responses. Non-immunological factors (including exposure intensity, behavior, and co-infections) may impact disease. However, given the consistent patterns seen across time and geography, these factors likely are less central. Strategies to protect children and adolescents from TB may need to differ by age and sex. Further work is required to better understand the contribution of age and sex to M. tuberculosis immunity

    The Role of Payment for Environmental Services toward Encouraging Energy Production in Illinois State Floodplains

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    The general objective of this research is to analyze different land use scenarios in a specific floodplain region of Illinois that utilizes levees in district setting. The specific objective for this research is as follows: 1) Analyze the current land use of the levee district overtime based on current crop production and farm practices. 2) Analyze alternative land use based on energy crops such as switchgrass. In this study we will attempt to estimate the potential biomass supply of levees in ten counties of Illinois State. We will focus on studying fifty two levee districts that are adjacent to the Illinois River. The levees are spread to ten counties in the state of Illinois. The data this paper uses is geospatial data to measure the amount of production potential of switchgrass in levee districts

    Before the whistle blows: developing new paradigms in tuberculosis screening to maximise benefit and minimise harm [version 1; peer review: awaiting peer review]

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    We summarise recent emerging evidence around tuberculosis (TB) transmission and its role in tuberculosis epidemiology, and in novel TB screening and diagnostic tests that will likely become available in low-resource settings in the near future. Little consideration has been paid to how these novel new tests will be implemented, nor what the consequences for individuals, communities and health systems will be. In particular, because of low specificity and consequent false-positive diagnoses, and the low percentage of people who “screen positive” that will go onto develop active pulmonary disease, there is significant potential for inappropriate initiation of TB treatment, as well as stigmatisation, loss of livelihoods and in some setting institutionalisation, with uncertain benefit for individual health or community transmission. We use analogy to prompt consideration of how and where new TB screening tests could be implemented in TB screening programmes in low-resource settings. Acceptance and confidence in TB screening programmes depends on well-functioning public health programmes that use screening algorithms that minimise harms and balance population benefits with autonomy and respect for individuals. Before new TB screening tests and algorithms are introduced, more evidence for their effectiveness, costs, benefits and harms under real-world conditions are required

    Reevaluating progression and pathways following Mycobacterium tuberculosis infection within the spectrum of tuberculosis

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    Traditional understanding of the risk of progression from Mycobacterium tuberculosis (Mtb) infection to tuberculosis (TB) overlooks diverse presentations across a spectrum of disease. We developed a deterministic model of Mtb infection and minimal (pathological damage but not infectious), subclinical (infectious but no reported symptoms), and clinical (infectious and symptomatic) TB, informed by a rigorous evaluation of data from a systematic review of TB natural history. Using a Bayesian approach, we calibrated the model to data from historical cohorts that followed tuberculin-negative individuals to tuberculin conversion and TB, as well as data from cohorts that followed progression and regression between disease states, disease state prevalence ratios, disease duration, and mortality. We estimated incidence, pathways, and 10-y outcomes following Mtb infection for a simulated cohort. Then, 92.0% (95% uncertainty interval, UI, 91.4 to 92.5) of individuals self-cleared within 10 y of infection, while 7.9% (95% UI 7.4 to 8.5) progressed to TB. Of those, 68.6% (95% UI 65.4 to 72.0) developed infectious disease, and 33.2% (95% UI 29.9 to 36.4) progressed to clinical disease. While 98% of progression to minimal disease occurred within 2 y of infection, only 71% and 44% of subclinical and clinical disease, respectively, occurred within this period. Multiple progression pathways from infection were necessary to calibrate the model and 49.5% (95% UI 45.6 to 53.7) of those who developed infectious disease undulated between disease states. We identified heterogeneous pathways across disease states after Mtb infection, highlighting the need for clearly defined disease thresholds to inform more effective prevention and treatment efforts to end TB

    Coherent Phonons in Bismuth Film Observed by Ultrafast Electron Diffraction

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    The generation of coherent phonons in polycrystalline bismuth film excited with femtosecond laser pulse is observed by ultrafast time-resolved electron diffraction. The dynamics of the diffracted intensities from the (110), (202), and (024) lattice planes show pronounced oscillations at 130-150 GHz. The origin of these coherent acoustic phonons is discussed in view of optical phonon decay into two acoustic phonons. Different drop times in the intensity of the diffraction orders are observed and interpreted as anisotropy in the energy transfer rate of coherent optical phonons
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