42 research outputs found
Towards an understanding of tensile deformation in Ti-based bulk metallic glass matrix composites with BCC dendrites
The microstructure and tension ductility of a series of Ti-based bulk metallic glass matrix composite (BMGMC) is investigated by changing content of the ÎČ stabilizing element vanadium while holding the volume fraction of dendritic phase constant. The ability to change only one variable in these novel composites has previously been difficult, leading to uninvestigated areas regarding how composition affects properties. It is shown that the tension ductility can range from near zero percent to over ten percent simply by changing the amount of vanadium in the dendritic phase. This approach may prove useful for the future development of these alloys, which have largely been developed experimentally using trial and error
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
Data on the early oxidation of SiO2-coated pure Ti and bulk Ti5Si3 at 800âŻÂ°C
Oxidation of pure Ti sputtered with a 250âŻnm layer of amorphous SiO2 and bulk Ti5Si3 was conducted at 800âŻÂ°C for 2 or 32âŻh in a 1 standard cubic centimeter per minute (SCCM) O2/4 SCCM Ar environment (approximately pO2 = 0.2âŻatm/20.3âŻkPa). Specimens were characterized using transmission electron microscopy, scanning transmission electron microscopy, and energy dispersive spectroscopy. The data in this article accompanies research article âEarly oxidation behavior of Si-coated titaniumâ [1], which contains further discussion. The data for this article is hosted at the Materials Commons data repository and is available for download at https://materialscommons.org/mcapp/#/data/dataset/b8bc8038-a735-4cb9-9a9e-a0fb912b248c