4 research outputs found

    Fabrication of Boron Nitride Fibers by Force Spinning Method

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    The unique multifunctional properties of boron nitride (BN) nanomaterials are identified as a parameter that would revolutionize electric propulsion in Aeronautics due to the lightweight ceramic with chemical inertness, high strength, high electrical resistivity and high thermal conductivity. Hexagonal BN (h-BN) nanofibers will enable new high-performance fibers that can be used in ceramic or polymer matrix composites, or thin films to provide revolutionary multifunctional ceramics for extreme environments and structures. Polymer derived h-BN materials have been previously demonstrated, providing an avenue to tailor properties of the ceramic end product. This effort also uses forcespinning (FS) technology that produces continuous non-woven nanofibers in a range of diameters depending on the processing parameters with a large production rate of 1 g/min allowing for manufacturing scale production. FTIR, SEM, TGA and XRD were used to characterize the materials in each processing steps

    Development of Structural Energy Storage for Aeronautics Applications

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    The National Aeronautics and Space Administration (NASA) has identified Multifunctional Structures for High Efficiency Lightweight Load-bearing Storage (M-SHELLS) as critical to development of hybrid gas-electric propulsion for commercial aeronautical transport in the N+3 timeframe. The established goals include reducing emissions by 80 and fuel consumption by 60 from todays state of the art. The advancement will enable technology for NASA Aeronautics Research Mission Directorates (ARMD) Strategic Thrust 3 to pioneer big leaps in efficiency and environmental performance for ultra-efficient commercial transports, as well as Strategic Thrust 4 to pioneer low-carbon propulsion technology in the transition to that scheme. The M-SHELLS concept addresses the hybrid gas-electric highest risk with its primary objective: to save structures energy storage system weight for future commercial hybrid electric propulsion aircraft by melding the load-carrying structure with energy storage in a single material. NASA's multifunctional approach also combines supercapacitor and battery chemistries in a synergistic energy storage arrangement in tandem with supporting good mechanical properties. The arrangement provides an advantageous combination of specific power, energy, and strength

    The major genetic determinants of HIV-1 control affect HLA class I peptide presentation.

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    Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection

    Global Impact of COVID-19 on Stroke Care and IV Thrombolysis

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    Objective To measure the global impact of COVID-19 pandemic on volumes of IV thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with 2 control 4-month periods. Methods. We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases. Results. There were 91,373 stroke admissions in the 4 months immediately before compared to 80,894 admissions during the pandemic months, representing an 11.5% (95% confidence interval [CI] −11.7 to −11.3, p \u3c 0.0001) decline. There were 13,334 IVT therapies in the 4 months preceding compared to 11,570 procedures during the pandemic, representing a 13.2% (95% CI −13.8 to −12.7, p \u3c 0.0001) drop. Interfacility IVT transfers decreased from 1,337 to 1,178, or an 11.9% decrease (95% CI −13.7 to −10.3, p = 0.001). Recovery of stroke hospitalization volume (9.5%, 95% CI 9.2–9.8, p \u3c 0.0001) was noted over the 2 later (May, June) vs the 2 earlier (March, April) pandemic months. There was a 1.48% stroke rate across 119,967 COVID-19 hospitalizations. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was noted in 3.3% (1,722/52,026) of all stroke admissions. Conclusions. The COVID-19 pandemic was associated with a global decline in the volume of stroke hospitalizations, IVT, and interfacility IVT transfers. Primary stroke centers and centers with higher COVID-19 inpatient volumes experienced steeper declines. Recovery of stroke hospitalization was noted in the later pandemic months
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