Explicating the Conditions Under Which Multilevel Multiple Imputation Mitigates Bias Resulting from Random Coefficient-Dependent Missing Longitudinal Data

Random coefficient dependent (RCD) missingness is a non-ignorable mechanism through which missing data can arise in longitudinal designs. RCD, for which we cannot test, is a problematic form of missingness that occurs if subject-specific random effects correlate with propensity for missingness or dropout. Particularly when covariate missingness is a problem, investigators typically handle missing longitudinal data by using single-level multiple imputation procedures implemented with long-format data, which ignores within-person dependency entirely, or implemented with wide-format (i.e., multivariate) data, which ignores some aspects of within-person dependency. When either of these standard approaches to handling missing longitudinal data is used, RCD missingness leads to parameter bias and incorrect inference. We explain why multilevel multiple imputation (MMI) should alleviate bias induced by a RCD missing data mechanism under conditions that contribute to stronger determinacy of random coefficients. We evaluate our hypothesis with a simulation study. Three design factors are considered: intraclass correlation (ICC; ranging from .25 to .75), number of waves (ranging from 4 to 8), and percent of missing data (ranging from 20% to 50%). We find that MMI greatly outperforms the single-level wide-format (multivariate) method for imputation under a RCD mechanism. For the MMI analyses, bias was most alleviated when the ICC is high, there were more waves of data, and when there was less missing data. Practical recommendations for handling longitudinal missing data are suggested

Basophil Phenotypes in Chronic Idiopathic Urticaria in Relation to Disease Activity and Autoantibodies

Potentially pathogenic IgG autoantibodies to IgE or its receptor, FcεRIα, have been detected in ~40% of chronic idiopathic urticaria (CIU) patients. CIU patients' basophils display distinct altered FcεRIα-mediated degranulation. CIU patients with basophil histamine release in response to polyclonal goat anti-human IgE ≥10% are classified as CIU responders (CIU-R) and <10% are CIU non-responders (CIU-NR). We compared the presence of autoantibodies to basophil degranulation phenotypes and to disease status (active or inactive). Sera were collected from non-CIU subjects and CIU subjects who participated in a longitudinal study of disease severity and had defined basophil degranulation phenotypes. Immunoenzymetric assays (IEMA) quantified IgG anti-FcεRIα and anti-IgE. IgG anti-FcεRIα antibody was detected in 57% of CIU-R (n=35), 55% of CIU-NR (n=29), and 57% of non-CIU subjects (n=23), whereas IgG anti-IgE was present in 43% of CIU-R, 45% of CIU-NR, and 30% of non-CIU subjects. Both the autoantibody levels and the functional basophil phenotype remained stable in subjects with active disease (n=16), whereas there was an enhancement in basophil function as subjects evolved into a state of remission (n=6), which appears independent of the presence of autoantibody. IEMAs detected a similar frequency of autoantibodies in CIU-R, CIU-NR, and non-CIU subjects. Basophil function may be independent of IEMA-detected autoantibodies

Chemical Composition by Neutron Activation Analysis (INAA) of Neo-Assyrian Palace Ware from Iraq, Syria and Israel

Neo-Assyrian Palace Ware is an 8th-7th century B.C.E. fine-ware which originated in Northern Mesopotamia and spread throughout the greater Levant. The mechanism by which Palace Ware moved across the Neo-Assyrian imperial landscape (trade or local imitation/emulation) is of great archaeological interest. This dataset provides chemical compositional data, generated using instrumental neutron activation analysis (INAA), for Palace Ware vessels from Nimrud and Nineveh, in the Assyrian imperial core (Iraq), Dūr-Katlimmu, in one of the annexed provinces (Syria), and Tell Jemmeh, located outside the Neo-Assyrian provincial system (Israel)

Blunt cerebrovascular injuries in the craniofacial fracture population - Are we screening the right patients?

Current knowledge of blunt cerebrovascular injuries (BCVIs) in craniomaxillofacial fracture (CMF) patients is limited. The purpose of this study was to determine the occurrence of BCVIs in patients with all types of CMF. This retrospective study included CMF patients in a level 1 trauma centre during a 3-year period. Patients who were not imaged with computed tomography angiography and patients with mechanisms other than blunt injury were excluded. The primary outcome variable was BCVI. A total of 753 patients were included in the analysis. A BCVI was detected in 4.4% of the patients screened. BCVIs occurred in 8.7% of cranial fracture patients, 7.1% of combined craniofacial fracture patients, and 3.1% of facial fracture patients. The risk of BCVI was significantly increased in patients with isolated cranial fractures (odds ratio (OR) 2.55, 95% confidence interval (CI) 1.18?5.50; P = 0.017), those involved in motor vehicle accidents (OR 3.42, 95% CI 1.63?7.17; P = 0.001), and those sustaining high-energy injuries (OR 3.17, 95% CI 1.57?6.40; P = 0.001). BCVIs in CMF patients are relatively common in highenergy injuries. However, these injuries also occur in minor traumas. Imaging thresholds should be kept low in this patient population when BCVIs are suspected.Peer reviewe

Cervical spine injuries in facial fracture patients - injury mechanism and fracture type matter

Evidence supports the notion that craniofacial fractures are significant predictors of cervical spine injuries (CSIs), but some debate remains on the injury mechanism of co-existing CSIs in craniofacial fractures and the relationship between CSI and specific facial fractures. In this retrospective study, we aim to assess the incidence rates of specific facial fracture types as well as other important variables and their relationship with CSIs. The primary outcome variable, CSI, and several predictor variables, including facial fracture type, were evaluated with logistic regression analyses. Of 2919 patients, the total CSI incidence rate was 3.0%. Rates of CSI in patients with isolated mandibular fractures (OR 0.26 CI 0.10, 0.63; p = 0.006) were lower than those previously reported, whereas isolated nasal fractures were strongly associated with CSI (OR 2.67 CI 1.36, 5.22; p = 0.004). Patients with concomitant cranial injuries were twice as likely to have CSI (OR 2.00, CI 1.22, 3.27; p = 0.006). Even though there is a strong occurrence rate of CSIs in patients with cranial injuries, clinicians should be aware that patients presenting with isolated facial fractures are at significant risk for sustaining CSIs also. (C) 2021 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Does postoperative orbital volume predict postoperative globe malposition after blow-out fracture reconstruction? A 6-month clinical follow-up study

Purpose: The aim of this study was to investigate the relationship between intraorbital volume change caused by orbital fracture and globe malposition (GMP) in blow-out fracture patients undergoing surgery and to clarify the significance of different radiologically detected predictors associated with GMP.Patients and methods: A 6-month prospective follow-up study of unilateral isolated orbital fractures was designed and implemented. The main outcome variable was GMP (present or absent); the secondary outcome was orientation of GMP (horizontal or vertical). The primary predictor variable was postoperative orbital volume difference determined as the difference between the fractured and non-fractured orbit (measured in milliliter and analyzed in milliliter and percentages). The explanatory variables were gender, age, treatment delay from trauma to surgery, fracture site, horizontal depth of the fracture, fracture area, maximum vertical dislocation of the fracture, and preoperative volume difference.Results: A total of 15 patients fulfilled the inclusion criteria and were followed for 6months from a larger cohort. GMP was detected in 6/15 patients (40.0%). GMP was more often present in large (2.5cm(2)) fractures (55.6%), in combined orbital fractures (50.0%), and in fractures with preoperative volume difference 2.5ml (62.5%) regardless of the postoperative volume correction. Postoperatively, patients with and without GMP displayed overcorrection of orbital volume; 4.15% corresponded to 1.15ml (with GMP) and 7.6% corresponded to 1.9ml (without GMP).Conclusion: GMP was present in large and combined orbital fractures. Clinically detectable postoperative GMP occurred despite satisfactory orbital reconstruction and overcorrection. Mild GMP, however, is not significant for the patient.</div

Does postoperative orbital volume predict postoperative globe malposition after blow-out fracture reconstruction? A 6-month clinical follow-up study

PurposeThe aim of this study was to investigate the relationship between intraorbital volume change caused by orbital fracture and globe malposition (GMP) in blow-out fracture patients undergoing surgery and to clarify the significance of different radiologically detected predictors associated with GMP.Patients and methodsA 6-month prospective follow-up study of unilateral isolated orbital fractures was designed and implemented. The main outcome variable was GMP (present or absent); the secondary outcome was orientation of GMP (horizontal or vertical). The primary predictor variable was postoperative orbital volume difference determined as the difference between the fractured and non-fractured orbit (measured in milliliter and analyzed in milliliter and percentages). The explanatory variables were gender, age, treatment delay from trauma to surgery, fracture site, horizontal depth of the fracture, fracture area, maximum vertical dislocation of the fracture, and preoperative volume difference.ResultsA total of 15 patients fulfilled the inclusion criteria and were followed for 6months from a larger cohort. GMP was detected in 6/15 patients (40.0%). GMP was more often present in large (2.5cm(2)) fractures (55.6%), in combined orbital fractures (50.0%), and in fractures with preoperative volume difference 2.5ml (62.5%) regardless of the postoperative volume correction. Postoperatively, patients with and without GMP displayed overcorrection of orbital volume; 4.15% corresponded to 1.15ml (with GMP) and 7.6% corresponded to 1.9ml (without GMP).ConclusionGMP was present in large and combined orbital fractures. Clinically detectable postoperative GMP occurred despite satisfactory orbital reconstruction and overcorrection. Mild GMP, however, is not significant for the patient.Peer reviewe

Settling the half-life of ⁶⁰Fe: fundamental for a versatile astrophysical chronometer

In order to resolve a recent discrepancy in the half-life of ⁶⁰Fe, we performed an independent measurement with a new method that determines the ⁶⁰Fe content of a material relative to Fe55 (t1/2=2.744yr) with accelerator mass spectrometry. Our result of (2.50±0.12)×10⁶yr clearly favors the recently reported value (2.62±0.04)×10⁶yr, and rules out the older result of (1.49±0.27)×10⁶yr. The present weighted mean half-life value of (2.60±0.05)×10⁶yr substantially improves the reliability as an important chronometer for astrophysical applications in the million-year time range. This includes its use as a sensitive probe for studying recent chemical evolution of our Galaxy, the formation of the early Solar System, nucleosynthesis processes in massive stars, and as an indicator of a recent nearby supernova.Part of this work was funded by the Austrian Science Fund (FWF) Projects No. AP20434 and AI00428 (FWF and CoDustMas, Eurogenesis via ESF)