695915 research outputs found
Sort by
Microwave Bandpass Filter By Feedback Interference Topology
No full textThis paper proposes a signal feedback interference topology to control the characteristics of a coupled line bandpass filter. Control is carried out by varying the ratio of the transmission line parameters of the forward and the feedback couplers. The topology produces a compact filter that does not require a complicated design or fabrication. The results of the insertion and return losses show that the feedback-controlled design has desirable features in terms of the design frequency, fractional bandwidth, stopband rejection level, roll-off rate and insertion loss. The test results of the fabricated prototype achieved good agreement with the simulation results of the ideal transmission line design model. Several microwave, modern wireless and mobile/satellite communication systems may benefit from such a filter design due to its compactness and flexibility
Impact of high tumor mutational burden in solid tumors and challenges for biomarker application
No full textAccurate identification of patients with solid tumors likely to respond to immunotherapy is crucial. Tumor mutational burden (TMB) measures the number of somatic mutations in a tumor and is an emerging prognostic and predictive biomarker for anti-programmed cell death (PD) 1/anti-PD-ligand 1 therapy and other immunotherapeutic agents. Tumor mutational burden is assessed optimally by whole exome sequencing, but next generation sequencing provides TMB estimates in a more timely and cost-effective manner. Blood-based measurement of TMB in plasma offers an alternative to the need for adequate tumor tissue for molecular testing, and has demonstrated the ability to identify patients who derive benefit from immunotherapy. Tumor mutational burden has diverse prognostic impact in different solid tumor types and also has a demonstrated role in predicting improved survival in patients receiving immunotherapy. There are challenges to TMB adoption into standard clinical practice, including variations in its definition, with the mutational number defining TMB-high appearing to vary across cancer types. The magnitude of TMB also varies across different tumor types, with the highest levels reported in melanoma and other skin cancers (where ultraviolet light is the dominant mutational process), followed by non-small cell lung cancer and other squamous carcinomas. Concerns regarding inter-laboratory and inter-platform variations in analysis methods have been raised, highlighting the need for standardization. Integration of other genomic or pathological biomarkers with TMB may increase its prognostic and predictive capabilities and validation of individual or combination models in prospective trials is warranted
Contrasting environmental preferences of photosynthetic and non-photosynthetic soil cyanobacteria across the globe
No full textAim: Cyanobacteria have shaped the history of life on Earth, and continue to play important roles as carbon and nitrogen fixers in terrestrial ecosystems. However, their global distribution and ecological preferences remain poorly understood, particularly for two recently discovered non-photosynthetic cyanobacterial classes (Sericytochromatia and Melainabacteria).Location: 237 locations across six continents encompassing multiple climates (arid, temperate, tropical, continental and polar) and vegetation types (forests, grasslands and shrublands).Time period: Sampling was carried out between 2003 and 2015.Major taxa studied: Photosynthetic and non-photosynthetic cyanobacterial taxaMethods: We conducted a field survey and used co-occurrence network analysis and structural equation modelling to evaluate the distribution and environmental preferences of soil cyanobacteria across the globe. These ecological preferences were used to create a global atlas (predictive distribution maps) of soil cyanobacteria.Results: Network analyses identified three major groups of cyanobacteria taxa, which resembled the three main cyanobacterial classes: the photosynthetic Oxyphotobacteria-dominated cluster, which were prevalent in arid and semiarid areas, and the non-photosynthetic Sericytochromatia- and Melainabacteria-dominated clusters, which preferred hyperarid oligotrophic and acidic/ humid environments, respectively.Main conclusions: This study provides novel insights into the environmental preferences of non-photosynthetic cyanobacteria in soils globally. Our findings highlight the contrasting environmental preferences among the three clusters of cyanobacteria and suggest that alterations in environmental conditions linked to climate change may result in important changes in the ecology and biogeography of these functionally important microorganisms
The lunar surface as a recorder of astrophysical processes
No full textThe lunar surface has been exposed to the space environment for billions of years and during this time has accumulated records of a wide range of astrophysical phenomena. These include solar wind particles and thecosmogenic products of solar particle events which preserve a record of the past evolution of the Sun, and cosmogenic nuclides produced by high-energy galactic cosmic rays which potentially record the galactic environment of the Solar System through time. The lunar surface may also have accreted material from the local interstellar medium, including supernova ejecta and material from interstellar clouds encountered by the Solar System in the past. Owing to the Moon’s relatively low level of geological activity, absence of an atmosphere,and, for much of its history, lack of a magnetic field, the lunar surface is ideally suited to collect these astronomical records. Moreover, the Moon exhibits geological processes able to bury and thus both preserve and ‘time-stamp’ these records, although gaining access to them is likely to require a significant scientific infrastructure on the lunar surface
Cooperative Pollution Source Exploration and Cleanup with a Bio-inspired Swarm Robot Aggregation
No full textCovid-19 and myositis - unique challenges for patients
No full textObjective. The Covid-19 pandemic and the subsequent effects on healthcare systems is having a significant effect on the management of long-term autoimmune conditions. The aim of this study was to assess the problems faced by patients with idiopathic inflammatory myopathies (IIM). Methods. An anonymized eSurvey was carried, with a focus on effects on disease control, continuity of medical care, drug procurance, and prevalent fears in the patient population.Results. Of the 608 participants (81.1% female, median ± SD age 57 ±13.9 years), dermatomyositis was the most frequent subtype (247, 40.6%). Patients reported health-related problems attributable to the Covid-19 pandemic (n=195, 32.1%); specifically 102 (52.3%) required increase in medicines, and 35 (18%) required hospitalization for disease-related complications. Over half (52.7%) of the surveyed patients were receiving glucocorticoids and/or had underlying cardiovascular risk factors (53.8%), placing them at higher risk for severe Covid-19. Almost one in four patients faced hurdles in procuring medicines. Physiotherapy, critical in the management of IIM, was disrupted in 214 (35.2%). One quarter (159, 26.1%) experienced difficulty in contacting their specialist, and 30 (4.9%) were unable to do so. Most (69.6%) were supportive of the increased use of remote consultations to maintain continuity of medical care during the pandemic. Conclusion. This large descriptive study suggests that the Covid-19 pandemic has incurred a detrimental effect on continuity of medical care for many patients with IIM. There is concern that delays and omissions in clinical care may potentially translate to poorer outcomes in the future.<br/
Insights into the knowledge, attitude and practices for the treatment of idiopathic inflammatory myopathy from a cross-sectional cohort survey of physicians
No full textIntroduction The idiopathic inflammatory myopathies (IIM) are heterogeneous and lead to high morbidity and mortality. Knowledge deficits among healthcare professionals could be detrimental to clinical care. Identifying areas of deficient Knowledge, Attitude and Practice (KAP) of IIM can improve physician education and patient outcomes. Aims To assess the proportion of physicians treating IIM with poor KAP and identify the key areas of deficit. Methods An anonymised and validated e-survey (57 questions) was circulated among physicians treating IIM (purposive sampling). Responses were evaluated using the Likert scale for good (>70% correct response), poor (>20% chose >2 answers) and the rest as intermediate consensus. Descriptive statistics were used. Intergroup comparisons were done using non-parametric tests. Results Of 80 (9.1% of 883) respondents, 90% were Rheumatologists and 37.5% Academicians. The knowledge base of treating physicians was good in specific domains such as triggers (80-90%), clinical presentation (MDA5, statin myositis, steroid myopathy, anti-synthetase syndrome)(82-92%), IIM mimics (41-89%), investigations (23-92%) and risk of osteoporosis in IIM(79%). There is also an intermediate knowledge base/consensus for outcome measures(30-56%) and response criteria(30-53%). There was poor knowledge and consensus on trials(27-34%), EULAR/ACR criteria(31%) and exercise-based interventions(17-62%). While 90% agree on the need for muscle biopsy to diagnose polymyositis, only one-third advocated it for juvenile and adult DM. Conclusion Physicians have a good understanding of the triggers, clinical presentation and mimics of IIM. Poor to intermediate knowledge and consensus exists regarding muscle biopsy, outcome measures, response criteria and exercise-based interventions, which could be addressed through future focussed educational initiatives
Self-assembled perovskite nanowire clusters for high luminance red light-emitting diodes
No full textBright red emission (620-650 nm) from perovskite light-emitting diodes (PeLEDs) is usually achieved via a composition including both bromine and iodine anions, which results in poor performance and stability due to phase separation under operating conditions. Here we devise a large-scale ligand-assisted reprecipitation method with nonpolar solvent that enables the fabrication of CsPbI3 nanowire clusters, emitting at 600 nm. The blue-shift of this emission relative to that of bulk CsPbI3 (~700 nm) is attributed to quantum confinement in nanowires. The growth of the nanowires is along the [011] crystal direction and is vacancy driven, resulting in the healing of surface defects and thereby a high photoluminescence yield of 91%. The clusters with ultralow trap density show remarkable structural and environmental stability. PeLEDs based on these clusters exhibit an external quantum efficiency of 6.2% with Commission Internationale de l’Eclairage coordinates of (0.66, 0.34), and record luminance of 13,644 cd m-2 of red electroluminescence. The half-lifetime under an accelerated stability test is 13.5 mins for an unencapsulated device in ambient conditions operating at an initial luminance of 11,500 cd m-2, which corresponds to an estimated half-lifetime of 694 h at 100 cd m-2 based on acceleration factor obtained by experimental testing
Positioning theory in applied linguistics: research design and applications
No full textThis chapter focuses on the link between positioning theory and applied linguistics research. The chapter explains how various social and poststructural concepts in applied linguistics scholarship can be better examined and understood in light of positioning theory. More specifically, the chapter provides guidelines for investigating speaker rights, learning opportunities, identities, language socialization, and culture and moral values in bilingual and multilingual contexts, using positioning theory as a theoretical framework or analytic approach