Plaster of Paris [poP, CaSO4·(1)/(2) H2O] is the standard phantom material used for the calibration of in vivo X-ray fluorescence (IVXRF)-based systems of bone metal quantification (i.e bone strontium and lead). Calibration of IVXRF systems of bone metal quantification employs the use of a coherent normalization procedure which requires the application of a coherent correction factor (CCF) to the data, calculated as the ratio of the relativistic form factors of the phantom material and bone mineral. Various issues have been raised as to the suitability of poP for the calibration of IVXRF systems of bone metal quantification which include its chemical purity and its chemical difference from bone mineral (a calcium phosphate). This work describes the preparation of a chemically pure hydroxyapatite phantom material, of known composition and stoichiometry, proposed for the purpose of calibrating IVXRF systems of bone strontium and lead quantification as a replacement for poP. The issue with contamination by the analyte was resolved by preparing pure Ca(OH)2 by hydroxide precipitation, which was found to bring strontium and lead levels to <0.7 and <0.3 μg/g Ca, respectively. HAp phantoms were prepared from known quantities of chemically pure Ca(OH)2, CaHPO4·2H2O prepared from pure Ca(OH)2, the analyte, and a HPO4(2-) containing setting solution. The final crystal structure of the material was found to be similar to that of the bone mineral component of NIST SRM 1486 (bone meal), as determined by powder X-ray diffraction spectrometry.

Aim:The cognitive, emotional, behavioral and physical impairments experienced by adults after mild traumatic brain injury (mTBI) can produce substantial disability, with 15–20% requiring referral to tertiary care (TC) for persistent symptoms.Methods:A convenience sample of 201 adult patients referred to TC as a result of mTBI was studied. Self-reported data were collected at first TC visit, on average 10 months postinjury. Patients reported the type and intensity of healthcare provider visit(s) undertaken while awaiting TC.Results:On average males reported 37 and females 30 healthcare provider visits, resulting in over $500,000 Canadian dollars spent on potentially excess mTBI care over 1 year.Discussion:Based on conservative estimate of 15% of mTBI patients receiving TC, this finding identifies a possible excess in care of $110 million for Ontario. Accurate diagnosis of mTBI and early coordination of follow-up care for those needing TC could increase cost–effectiveness.

Background Among critically ill patients with acute kidney injury (AKI), earlier initiation of renal replacement therapy (RRT) may mitigate fluid accumulation and confer better outcomes among individuals with greater fluid overload at randomization. Methods We conducted a pre-planned post hoc analysis of the STandard versus Accelerated initiation of Renal Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial. We evaluated the effect of accelerated RRT initiation on cumulative fluid balance over the course of 14 days following randomization using mixed models after censoring for death and ICU discharge. We assessed the modifying effect of baseline fluid balance on the impact of RRT initiation strategy on key clinical outcomes. Patients were categorized in quartiles of baseline fluid balance, and the effect of accelerated versus standard RRT initiation on clinical outcomes was assessed in each quartile using risk ratios (95% CI) for categorical variables and mean differences (95% CI) for continuous variables. Results Among 2927 patients in the modified intention-to-treat analysis, 2738 had available data on baseline fluid balance and 2716 (92.8%) had at least one day of fluid balance data following randomization. Over the subsequent 14 days, participants allocated to the accelerated strategy had a lower cumulative fluid balance compared to those in the standard strategy (4509 (− 728 to 11,698) versus 5646 (0 to 13,151) mL, p = 0.03). Accelerated RRT initiation did not confer greater 90-day survival in any of the baseline fluid balance quartiles (quartile 1: RR 1.11 (95% CI 0.92 to 1.34), quartile 2: RR 1.03 (0.87 to 1.21); quartile 3: RR 1.08 (95% CI 0.91 to 1.27) and quartile 4: RR 0.87 (95% CI 0.73 to 1.03), p value for trend 0.08). Conclusions Earlier RRT initiation in critically ill patients with AKI conferred a modest attenuation of cumulative fluid balance. Nonetheless, among patients with greater fluid accumulation at randomization, accelerated RRT initiation did not have an impact on all-cause mortality. Trial registration: ClinicalTrials.gov number, https://clinicaltrials.gov/ct2/show/NCT02568722, registered October 6, 2015.

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A non-destructive, multi-elemental analytical method using energy dispersive x-ray fluorescence (EDXRF) spectrometry was developed for the quantification of enamel-manganese (MnE) for comparison to dietary and tap water intakes of Mn, as well as children’s height, Weschler Abbreviated Scale of Intelligence Quotient (IQ) test scores and Santa Ana (SA) dexterity test scores. Using the novel analytical method, enamel-iron (FeE), copper (CuE), zinc (ZnE) and lead (PbE) were also quantified and correlated to one another and to children’s height, IQ test scores and SA dexterity test scores. Significant positive correlations were observed between all essential trace elements in surface enamel (Mn, Fe, Cu, Zn). MnE was found to have a weak correlation with estimated dietary intake of Mn (p < 0.01). No significant correlations were found between oral ingestion of Fe and FeE. Metal concentrations were observed to be highest in incisor enamel for all elements except zinc.