The pulsed-neutron method has been used to measure the temperature dependence of both the diffusion constant and the extrapolated end point in water. The measured temperature dependence of the diffusion constant was found to be in good agreement with the theoretical values predicted by the Nelkin kernel.Measurements of the extrapolated end point in a cylinder of diameter 7 in. and height 7 in. gave a value of 0·323 ± 0·013 cm, with a similar result for a 7 in. cubical system. For an 8 in. diameter cylinder 4 in. high, however, the value was 0·465 ± 0·039 cm, a change which would not be expected theoretically. The extrapolated end point was also measured at temperatures up to 250°C. For a 4 in. high cylinder no definite temperature dependence was observed, but in a 16 in. high cylinder there was an increase with temperature from 0·340 ± 0·030 cm at 18°C to 0·469 ± 0·021 cm at 250°C.
Background As a pragmatic randomised timing-of-birth trial, WILL adapted its trial procedures in response to the COVID-19 pandemic. These are reviewed here to inform post-pandemic trial methodology. Methods The trial (internal pilot) paused in March 2020, re-opened in July 2020, and is currently recruiting in 37 UK NHS consultant-led maternity units. We evaluated pandemic adaptations made to WILL processes and surveyed sites for their views of these changes (20 sites, videoconference). Results Despite 88% of sites favouring an electronic investigator site file (ISF), information technology requirements and clinical trial unit (CTU) operating procedures mandated the ongoing use of paper ISFs; site start-up delays resulted from restricted access to the CTU. Site initiation visits (SIVs) were conducted remotely; 50% of sites preferred remote SIVs and 44% felt that it was trial-dependent, while few preferred SIVs in-person as standard procedure. The Central team felt remote SIVs provided scheduling and attendance flexibility (for sites and trial staff), the option of recording discussions for missing or future staff, improved efficiency by having multiple sites attend, and time and cost savings; the negative impact on rapport-building and interaction was partially mitigated over time with more familiarity with technology and new ways-of-working. Two methods of remote consent were developed and used by 30/37 sites and for 54/156 recruits. Most (86%) sites using remote consenting felt it improved recruitment. For remote data monitoring (5 sites), advantages were primarily for the monitor (e.g. flexibility, no time constraints, reduced cost), and disadvantages primarily for the sites (e.g. document and access preparation, attendance at a follow-up meeting), but 81% of sites desired having the option of remote monitoring post-pandemic. Conclusions COVID adaptations to WILL trial processes improved the flexibility of trial delivery, for Central and site staff, and participants. Flexibility to use these strategies should be retained post-pandemic. Trial registration ISRCTN77258279. Registered on 05 December 2018.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.