Small specimen compact tension testing of ceramics

The small size compact tensile specimen is useful for measurement of the fracture toughness of ceramics. The tabular data available for the compliance factor are accurately fitted by a polynominal expression. The elimination of residual stress is important for accurate measurement of the fracture toughness. [on SciFinder (R)

Ferritin trajectories over repeated whole blood donations: results from the FIND+ study

BACKGROUND: Depending on post-donation erythropoiesis, available iron stores, and iron absorption rates, optimal donation intervals may differ between donors. This project aims to define subpopulations of donors with different ferritin trajectories over repeated donations. METHODS: Ferritin levels of 300 new whole blood donors were measured from stored (lookback) samples from each donation over two years in an observational cohort study. Latent classes of ferritin level trajectories were investigated separately using growth mixture models for male and female donors. General linear mixed models assessed associations of ferritin levels with subsequent iron deficiency and/or low hemoglobin. RESULTS: Two groups of donors were identified using group-based trajectory modeling in both genders. Ferritin levels showed rather linear reductions among 42.9% of male donors and 87.7% of female donors. For the remaining groups of donors, steeper declines in ferritin levels were observed. Ferritin levels at baseline and the end of follow-up varied greatly between groups. CONCLUSIONS: Repeated ferritin measurements show depleting iron stores in all-new whole blood donors, the level at which mainly depends on baseline ferritin levels. Tailored, less intensive donation strategies might help to prevent low iron in donors, and could be supported with ferritin monitoring and/or iron supplementation

Whole blood donors' post‐donation symptoms diminish quickly but are discouraging: Results from 6‐day symptom diaries

Background: Whole blood donors may experience post-donation symptoms such as fatigue, dizziness or headache after blood donation, which could influence donor retention. We aimed to examine post-donation symptoms during one week after whole blood donation, investigate donor characteristics associated with symptoms and evaluate associations between symptoms and donor return.Methods: During one week, whole blood donors who donated successfully at one of the collection centres in the Netherlands were invited to participate. 3076 Donors filled in a diary, assessing post-donation symptoms during day 1 to 6 after donation. We used linear mixed models analyses to determine the change in post-donation symptoms after donation for male and female donors separately. Furthermore, we investigated associations between post-donation symptoms and donors’ physical characteristics using multivariable regression and determined associations between symptoms and donor return.Results: Donors reported fatigue as the most common symptom, with approximately 3% of donors experiencing severe problems at the first day after donation. Multiple symptoms improved significantly up to day 3 after whole blood donation. Age, BMI, blood pressure (male donors) and blood volume (female donors) were significantly associated with post-donation symptoms. Donors with less fatigue after whole blood donation were more likely to return for their next donation within 31 days after receiving an invitation.Conclusion: Post-symptoms improve up to three days after whole blood donation. Our results may help blood collection centres to identify donors more prone to post-donation symptoms and provide personalized information about the presence and course of post-donation symptoms, possibly increasing donor return rates