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We present an analysis for metamaterial (MM) enhanced wireless power transfer (WPT) that includes new results revealing the impact of magnetostatic surface waves and their degradation of WPT efficiency. Our analysis shows that the commonly used fixed loss model used by previous works leads to the incorrect conclusion regarding the highest efficeincy MM configuration. Specifically, we show that the "perfect lens" configuration provides lower WPT efficiency enhancement in comparison to many other MM configurations and operating conditions. To understand why, we introduce a model for quantifying loss in MM-enhanced WPT and introduce a new figure of merit on efficiency enhancement, [Formula: see text]. Using both simulation and experimental prototypes, we show that while the "perfect-lens" MM achieves a field enhancement of four times the other configurations considered, its internal loss due to magnetostatic waves significantly reduces its efficiency-enhancement. Surprisingly, all the MM configurations analyzed other than the "perfect-lens" achieved higher efficiency enhancement in simulation and in experiment than the perfect lens.
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PurposeWe aimed to describe the demographics, cancer subtypes, comorbidities and outcomes of patients with a history of cancer with COVID-19 from March to June 2020. Secondly, we compared patients hospitalized with COVID-19 to patients diagnosed with COVID-19 and patients hospitalized with influenza. MethodsWe conducted a cohort study using eight routinely-collected healthcare databases from Spain and the US, standardized to the Observational Medical Outcome Partnership common data model. Three cohorts of patients with a history of cancer were included: i) diagnosed with COVID-19, ii) hospitalized with COVID-19, and iii) hospitalized with influenza in 2017-2018. Patients were followed from index date to 30 days or death. We reported demographics, cancer subtypes, comorbidities, and 30-day outcomes. ResultsWe included 118,155 patients with a cancer history in the COVID-19 diagnosed and 41,939 in the COVID-19 hospitalized cohorts. The most frequent cancer subtypes were prostate and breast cancer (range: 5-19% and 1-14% in the diagnosed cohort, respectively). Hematological malignancies were also frequent, with non-Hodgkins lymphoma being among the 5 most common cancer subtypes in the diagnosed cohort. Overall, patients were more frequently aged above 65 years and had multiple comorbidities. Occurrence of death ranged from 8% to 14% and from 18% to 26% in the diagnosed and hospitalized COVID-19 cohorts, respectively. Patients hospitalized with influenza (n=242,960) had a similar distribution of cancer subtypes, sex, age and comorbidities but lower occurrence of adverse events. ConclusionPatients with a history of cancer and COVID-19 have advanced age, multiple comorbidities, and a high occurence of COVID-19-related events. Additionaly, hematological malignancies were frequent in these patients.This observational study provides epidemiologic characteristics that can inform clinical care and future etiological studies.
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ObjectivesA plethora of medicines have been repurposed or used as adjunctive therapies for COVID-19. We characterized the utilization of medicines as prescribed in routine practice amongst patients hospitalized for COVID-19 in South Korea, China, Spain, and the USA. DesignInternational network cohort SettingHospital electronic health records from Columbia University Irving Medical Centre (NYC, USA), Stanford (CA, USA), Tufts (MA, USA), Premier (USA), Optum EHR (USA), department of veterans affairs (USA), NFHCRD (Honghu, China) and HM Hospitals (Spain); and nationwide claims from HIRA (South Korea) Participantspatients hospitalized for COVID-19 from January to June 2020 Main outcome measuresPrescription/dispensation of any medicine on or 30 days after hospital admission date AnalysesNumber and percentage of users overall and over time Results71,921 people were included: 304 from China, 2,089 from Spain, 7,599 from South Korea, and 61,929 from the USA. A total of 3,455 medicines were identified. Common repurposed medicines included hydroxychloroquine (<2% in NFHCRD to 85.4% in HM), azithromycin (4.9% in NFHCRD to 56.5% in HM), lopinavir/ritonavir (<3% in all US but 34.9% in HIRA and 56.5% in HM), and umifenovir (0% in all except 78.3% in NFHCRD). Adjunctive medicines were used with great variability, with the ten most used treatments being (in descending order): bemiparin, enoxaparin, heparin, ceftriaxone, aspirin, vitamin D, famotidine, vitamin C, dexamethasone, and metformin. Hydroxychloroquine and azithromycin increased rapidly in use in March-April but declined steeply in May-June. ConclusionsMultiple medicines were used in the first months of COVID-19 pandemic, with substantial geographic and temporal variation. Hydroxychloroquine, azithromycin, lopinavir-ritonavir, and umifenovir (in China only) were the most prescribed repurposed medicines. Antithrombotics, antibiotics, H2 receptor antagonists and corticosteroids were often used as adjunctive treatments. Research is needed on the comparative risk and benefit of these treatments in the management of COVID-19. O_TEXTBOXWhat is already known in this topicO_LIDrug repurposing is a common approach in the clinical management of novel diseases and conditions for which there are no available pharmacotherapies C_LIO_LIHydroxychloroquine was widely used in the management of COVID-19 patients during the early phases of the pandemic C_LIO_LIRecent NIH (and other) guidelines recommend the use of concomitant therapies including immune-based, antithrombotic, antibiotic and other treatments C_LI What this study addsO_LIThis study demonstrates great variability and extensive drug repurposing and utilization in the management of COVID-19 patients. C_LIO_LIA wide range of adjunctive treatments has been used, including antithrombotics, antibiotics, H2 receptor antagonists, and systemic corticosteroids. C_LIO_LIEmerging clinical data on the safety and efficacy of hydroxychloroquine and azithromycin impacted their rise and rapid decline in use internationally C_LIO_LIConversely, the use of corticosteroids grew only in more recent months, with little use in the early stages of the pandemic (January to April) C_LI C_TEXTBOX
