Round Robin Study Research Articles

The Alzheimer's Association Global Biomarker Standardization Consortium (GBSC) plasma phospho-tau Round Robin study.

Phosphorylated tau (p-tau) is a specific blood biomarker for Alzheimer's disease (AD) pathology. Multiple p-tau biomarkers on several analytical platforms are poised for clinical use. The Alzheimer's Association Global Biomarker Standardisation Consortium plasma phospho-tau Round Robin study engaged assay developers in a blinded case-control study on plasma p-tau, aiming to learn which assays provide the largest fold-changes in AD compared to non-AD, have the strongest relationship between plasma and cerebrospinal fluid (CSF), and show the most consistent relationships between methods (commutability) in measuring both patient samples and candidate reference materials (CRM). Thirty-three different p-tau biomarker assays, built on eight different analytical platforms, were used to quantify paired plasma and CSF samples from 40 participants. AD biomarker status was categorised as "AD pathology" (n=25) and "non-AD pathology" (n=15) by CSF Aβ42/Aβ40 (US-FDA; CE-IVDR) and p-tau181 (CE-IVDR) methods. The commutability of four CRM, at three concentrations, was assessed across assays. Plasma p-tau217 consistently demonstrated higher fold-changes between AD and non-AD pathology groups, compared to other p-tau epitopes. Fujirebio LUMIPULSE G, UGOT IPMS, and Lilly MSD p-tau217 assays provided the highest median fold-changes. In CSF, p-tau217 assays also performed best, and exhibited substantially larger fold-changes than their plasma counterparts, despite similar diagnostic performance. P-tau217 showed the strongest correlations between plasma assays (rho=0.81 to 0.97). Plasma p-tau levels were weakly-to-moderately correlated with CSF p-tau, and correlations were non-significant within the AD group alone. The evaluated CRM were not commutable across assays. Plasma p-tau217 measures had larger fold-changes and discriminative accuracies for detecting AD pathology, and better agreement across platforms than other plasma p-tau variants. Plasma and CSF markers of p-tau, measured by immunoassays, are not substantially correlated, questioning the interchangeability of their continuous relationship. Further work is warranted to understand the pathophysiology underlying this dissociation, and to develop suitable reference materials facilitating cross-assay standardisation. Alzheimer's Association (#ADSF-24-1284328-C).

Round Robin Study for Evaluation an in vitro skin irritation test for medical device extracts using KeraSkinTM in Korea

With the growing importance of alternative test methods that implement the 3Rs principles (Reduction, Refinement and Replacement) and the global importance of biological safety assessment data for medical devices is increasing. We have developed and optimized the ‘KeraSkin™ Skin Irritation Test (KeraSkin™ SIT) for medical device’ for regulatory application in biological evaluation according to ISO 10993-23. We conducted a round robin study to optimize and evaluate the performance of KeraSkin™ SIT for medical devices using KeraSkin™ Reconstructed Human Epidermis (RhE), which is developed and manufactured in Korea. This round robin study was performed to assess the transferability, reproducibility (within and between laboratories) and predictive capacity in 1 lead laboratory and 3 participating laboratories based on OECD Guidance Document 34. The predictive capacity, the results showed 83.3 % of sensitivity, 100 % of specificity and 91.6 % of accuracy. In conclusion, the results demonstrate that ‘KeraSkin™ SIT for medical device’ provides a robust test method for detecting irritant activity of medical device extracts and can be utilized for identifying low levels of potent irritants in medical device extracts. Therefore, it fulfills the requirements to be included as a ‘me-too’ test method to EpiDerm™ and SkinEthic™ skin irritation test in ISO 10993-23.

Perceiving Others Through a Screen: Are First Impressions of Personality Accurate and Normative via Videoconferencing?

The use of videoconferencing platforms has globally risen to facilitate face-to-face communication since the onset of COVID-19. But how do our first impressions of people we meet on Zoom compare to in-person interactions? Specifically, do we view others' personalities as accurately (in line with their unique personality) and normatively (in line with the average, desirable personality) as in-person? Across two Zoom first-impression round-robin studies (exploratory study: N = 567, Dyads = 3,053; preregistered replication: N = 371, Dyads = 1,961), which we compared to an in-person round-robin study (N = 306; Dyads = 1,682), people viewed others' personalities as accurately and as normatively on Zoom as in-person. Moreover, people better liked interaction partners they viewed more accurately and normatively. However, in interactions of poorer audio-video quality, people viewed others less accurately, less normatively, and liked them less. Overall, through a screen, our impressions of others are as accurate and normative as face-to-face, but it depends on the quality of that screen.

Crack Tip Localization in Adhesively Bonded CFRP-CFRP Joints subjected to Mode II Fatigue Loading

The use of resin-based composite materials in place of metals has gained prominence across various industries. Such composites offer a superior strength-to-weight ratio, addressing the increasing demand for lightweight structures to reduce emissions. As such, structural joining of composite materials is of growing importance. Traditional fasteners, however, not only compromise weight savings, but also introduce weak points within the structure. Adhesive bonding emerges as the most promising joining technology, balancing weight efficiency and performance. However, its broader adoption for primary structural joints is hindered by a lack of standardization of quality control and non-destructive inspection techniques and concerns about long-term reliability. To address this challenge, the “CERTBOND” COST Action initiative (CA18120) was established to investigate adhesive bonding and develop a reliable certification roadmap for bonded primary structures. As part of this initiative, a Mode II fatigue loading Round Robin study was conducted on adhesively bonded CFRP-CFRP End-Notched Flexure specimens. While conducting the fatigue tests, supplementary techniques for estimating the crack tip position were employed. The selected techniques included visual testing (employing two different methods), ultrasonic phased array testing, distributed strain sensing using optical backscatter reflectometry, digital image correlation, and localization by acoustic emission. The present study describes, compares and discusses the results obtained by the cited localization techniques.

A round-robin study on the tensile characterization of single fibres: A multifactorial analysis and recommendations for more reliable results

In this benchmark, the tensile properties of three types of organic fibres – flax, hemp and aramid − were determined using single-fibre tensile tests performed by nine research groups. Flax and hemp were chosen due to their prevalence among European fibre plants. Aramid was selected for its synthetic nature and comparable dimensional properties. Due to the morphological complexity and variability of plant fibres, the scatter in the apparent tangent modulus and strength is more pronounced for flax and hemp compared to aramid. The primary source of scatter in the tensile properties results from human factors and experimental procedures, particularly regarding the fibre selection, the measurement of the fibre cross-sectional area and of the tensile strain. The post-processing procedure also turns out to be a key factor. Finally, recommendations and guidelines for best practices are proposed to reduce the main sources of dispersion associated with the reproducibility of single fibre tensile tests.

Effective orifice diameter: a new sizing parameter of surgical valve prostheses to inform valve selection.

The labeled sizes of surgical valve prostheses and their discordance with the physical internal valve orifice sizes has long been a controversy in the cardiac surgery community, leading many to believe it to be a contributing factor in prosthesis-patient mismatch following valvular replacement surgery. In an attempt to address this issue, the International Organization for Standardization (ISO) 5840-2:2021 standard for surgical valve prostheses recommends that a new sizing parameter, namely, the effective orifice diameter, be provided in labeling by all manufacturers as an indicator of the true flow-passing capacity of a prosthetic valve. The ISO Cardiac Valves Working Group conducted a multi-laboratory round-robin study to investigate whether the effective orifice diameter of a prosthetic surgical valve could be derived repeatably and reproducibly through steady forward-flow testing. A total of seven valve models, each with multiple sizes, were tested, including a mechanical heart valve and multiple biological heart valves. The round-robin study confirmed that the steady forward-flow test had good intra-laboratory repeatability and inter-laboratory reproducibility in deriving the effective orifice diameters of surgical valve prostheses. On average, among the participating laboratories, the experimentally derived effective orifice diameter of a prosthetic heart valve was 3-12 mm smaller than its labeled size. The effective orifice diameter provides better characterization of the hydrodynamic characteristics of a surgical valve prosthesis and can be derived using a validated steady forward-flow test method. This new sizing parameter will soon be adopted by surgical valve manufacturers and provided in device labeling to inform valve selection by surgeons.

Comparative electron microscopy particle sizing of TiO2 pigments: sample preparation and measurement.

Titanium dioxide (TiO2) pigment is a non-toxic, particulate material in widespread use and found in everyone's daily life. The particle size of the anatase or rutile crystals are optimised to produce a pigment that provides the best possible whiteness and opacity. The average particle size is intentionally much larger than the 100 nm boundary of the EU nanomaterial definition, but the TiO2 pigment manufacturing processes results in a finite nanoscale content fraction. This optically inefficient nanoscale fraction needs to be quantified in line with EU regulations. In this paper, we describe the measurement procedures used for product quality assurance by three TiO2 manufacturing companies and present number-based primary particle size distributions (PSDs) obtained in a round-robin study performed on five anatase pigments fabricated by means of sulfate processes in different plants and commonly used worldwide in food, feed, pharmaceutical and cosmetic applications. The PSDs measured by the three titanium dioxide manufacturers based on electron micrographs are in excellent agreement with one another but differ significantly from those published elsewhere. Importantly, in some cases, the PSDs result in a different regulatory classification for some of the samples tested. The electron microscopy results published here are supported by results from other complementary methods including surface area measurements. It is the intention of this publication to contribute to an ongoing discussion on size measurements of TiO2 pigments and other particulate materials and advance the development of widely acceptable, precise, and reproducible measurement protocols for measuring the number-based PSDs of particulate products in the size range of TiO2 pigments.

Do Objective and Peer-perceived Qualities Moderate the Effect of Narcissism on Social Outcomes?

Narcissistic individuals have a strong desire for attracting short-term mates, being influential in groups, and attaining prestige and material wealth. Past research suggests that narcissistic individuals are also quite successful in attaining these outcomes and these effects are due to narcissists’ grandiose self-image and admiration-seeking tendency (i.e., admiration component of narcissism). In the current research, we investigated whether the effects of narcissistic admiration are moderated by specific qualities that are helpful for attaining the respective outcomes. Specifically, we tested whether physical attractiveness moderates the effect of narcissistic admiration on short-term mate appeal, whether intelligence and socio-emotional abilities moderate the effect on social influence, and whether intelligence moderates the effects on occupational prestige and material wealth. Analyzing data from a speed-dating study (Study 1, N = 397), a round-robin laboratory study (Study 2, N = 256), and a panel study representative of the German population (Study 3, N = 1,477), we found that narcissistic admiration and the respective qualities predicted the outcomes, but in most cases, their interactions were non-significant. There was one exception: Narcissistic admiration interacted with verbal intelligence in the sense that the effects of narcissistic admiration on occupational prestige and material wealth were more positive, the higher verbal intelligence was.

Effects of printer variation on vibration response of fused deposition modeling-fabricated elastic beams with symmetric and asymmetric resonators: A round robin study

Additive manufacturing has expanded rapidly as a production tool due to its ease of use for rapidly producing parts. The most common polymer-based additive approach is fused deposition modeling (FDM) which uses plastic filament to build parts additively, one line at a time, to build a 3D shape. FDM printers are ubiquitous in university, government and industry settings, making them ideal for mass-production of shared designs across institutions. While it is commonly known that FDM finished products have variations due to differences in printer model and slicing and extrusion settings, little has been done to quantify the effects of these variations on elasto-dynamic response. In this study, a multi-institutional round robin approach is used to quantify the printer-to-printer variations of a structure comprised of a thin beam with attached resonators. The parameters of the round robin study involve printing the same geometry, with the same base material, on whatever FDM-type printers are available at each of six contributing institutions. All samples were then sent to a common location and tested on the same apparatus to limit experimental variability. This presentation will discuss the design of the study, test and modeling efforts, and a summary of results.

In vitro bioaccessibility round robin testing for arsenic and lead in standard reference materials and soil samples.

In this study, we assessed the suitability of using a standard reference material (SRM) other than National Institute of Standards and Technology (NIST) 2710a or NIST 2711a in USEPA Method 1340 to determine arsenic (As) and lead (Pb) in vitro bioaccessibility (IVBA) and the capabilities of Canadian-based laboratories to perform the method. Five laboratories participated in an initial round robin study and analyzed NIST 2710a, NIST 2711a, BGS119, and Enviromat SS-2. Intra- and inter-laboratory variability were generally acceptable with percentage relative standard deviations (RSD) of less than 20%. The mean total As and Pb concentrations obtained for BGS119 (332 and 936 mg/kg, respectively) and the mean IVBA values (As = 14.3% and Pb = 78.1%) suggested it may be a suitable and acceptable SRM, whereas the concentration of As in Enviromat SS-2 as received (3.2 mg/kg) was deemed too low. Ten soil samples from sites with varying land use were analyzed in a follow-up round robin study using the modified IVBA method that included BGS119 as SRM. The concentrations of As and Pb in the IVBA extracts reported by the participating laboratories were comparable. The mean As IVBA values for the field-collected samples ranged from 0.1% to 56.4%; for Pb, they ranged from 7.0% to 121%. The lowest IVBA values were measured in mine site samples; the highest values were associated with smelter-affected soils. The low IVBA values correlated with high iron content. Intra- and interlaboratory reproducibility were acceptable (RSD < 30%). Based on the findings of the study, laboratories can use the modified method to provide reproducible and comparable As and Pb IVBA data. The use of BGS119 as an alternative SRM to assess contaminated sites in the province of British Columbia for regulatory purposes is recommended, as it is representative of As and Pb concentrations in contaminated soils in British Columbia. Integr Environ Assess Manag 2024;20:1486-1495. © 2024 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Round-Robin Study for Ice Adhesion Tests

Ice adhesion tests are widely used to assess the performance of potential icephobic surfaces and coatings. A great variety of test designs have been developed and used over the past decades due to the lack of formal standards for these types of tests. In many cases, the aim of the research was not only to determine ice adhesion values, but also to understand the key surface properties correlated to low ice adhesion surfaces. Data from different measurement techniques had low correspondence between the results: Values varied by orders of magnitude and showed different relative relationships to one another. This study sought to provide a broad comparison of ice adhesion testing approaches by conducting different ice adhesion tests with identical test surfaces. A total of 15 test facilities participated in this round-robin study, and the results of 13 partners are summarized in this paper. For the test series, ice types (impact and static) as well as test parameters were harmonized to minimize the deviations between the test setups. Our findings are presented in this paper, and the ice- and test-specific results are discussed. This study can improve our understanding of test results and support the standardization process for ice adhesion strength measurements.

The human factor: results of a small-angle scattering data analysis round robin

A round-robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5% and half of the population width entries within 40%. Due to the added complexity of the structure factor, far fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 and 86%, respectively. This round-robin experiment highlights several causes for the discrepancies, for which solutions are proposed.

On the reproducibility of extrusion-based bioprinting: round robin study on standardization in the field

The outcome of three-dimensional (3D) bioprinting heavily depends, amongst others, on the interaction between the developed bioink, the printing process, and the printing equipment. However, if this interplay is ensured, bioprinting promises unmatched possibilities in the health care area. To pave the way for comparing newly developed biomaterials, clinical studies, and medical applications (i.e. printed organs, patient-specific tissues), there is a great need for standardization of manufacturing methods in order to enable technology transfers. Despite the importance of such standardization, there is currently a tremendous lack of empirical data that examines the reproducibility and robustness of production in more than one location at a time. In this work, we present data derived from a round robin test for extrusion-based 3D printing performance comprising 12 different academic laboratories throughout Germany and analyze the respective prints using automated image analysis (IA) in three independent academic groups. The fabrication of objects from polymer solutions was standardized as much as currently possible to allow studying the comparability of results from different laboratories. This study has led to the conclusion that current standardization conditions still leave room for the intervention of operators due to missing automation of the equipment. This affects significantly the reproducibility and comparability of bioprinting experiments in multiple laboratories. Nevertheless, automated IA proved to be a suitable methodology for quality assurance as three independently developed workflows achieved similar results. Moreover, the extracted data describing geometric features showed how the function of printers affects the quality of the printed object. A significant step toward standardization of the process was made as an infrastructure for distribution of material and methods, as well as for data transfer and storage was successfully established.

Direct comparison and reproducibility of two segmentation methods for multicompartment dosimetry: round robin study on radioembolization treatment planning in hepatocellular carcinoma

PurposeInvestigate reproducibility of two segmentation methods for multicompartment dosimetry, including normal tissue absorbed dose (NTAD) and tumour absorbed dose (TAD), in hepatocellular carcinoma patients treated with yttrium-90 (90Y) glass microspheres.MethodsTARGET was a retrospective investigation in 209 patients with < 10 tumours per lobe and at least one tumour ≥ 3 cm ± portal vein thrombosis. Dosimetry was compared using two distinct segmentation methods: anatomic (CT/MRI-based) and count threshold-based on pre-procedural 99mTc-MAA SPECT. In a round robin substudy in 20 patients with ≤ 5 unilobar tumours, the inter-observer reproducibility of eight reviewers was evaluated by computing reproducibility coefficient (RDC) of volume and absorbed dose for whole liver, whole liver normal tissue, perfused normal tissue, perfused liver, total perfused tumour, and target lesion. Intra-observer reproducibility was based on second assessments in 10 patients ≥ 2 weeks later.Results99mTc-MAA segmentation calculated higher absorbed doses compared to anatomic segmentation (n = 209), 43.9% higher for TAD (95% limits of agreement [LoA]: − 49.0%, 306.2%) and 21.3% for NTAD (95% LoA: − 67.6%, 354.0%). For the round robin substudy (n = 20), inter-observer reproducibility was better for anatomic (RDC range: 1.17 to 3.53) than 99mTc-MAA SPECT segmentation (1.29 to 7.00) and similar between anatomic imaging modalities (CT: 1.09 to 3.56; MRI: 1.24 to 3.50). Inter-observer reproducibility was better for larger volumes. Perfused normal tissue volume RDC was 1.95 by anatomic and 3.19 by 99mTc-MAA SPECT, with corresponding absorbed dose RDC 1.46 and 1.75. Total perfused tumour volume RDC was higher, 2.92 for anatomic and 7.0 by 99mTc-MAA SPECT with corresponding absorbed dose RDC of 1.84 and 2.78. Intra-observer variability was lower for perfused NTAD (range: 14.3 to 19.7 Gy) than total perfused TAD (range: 42.8 to 121.4 Gy).ConclusionAnatomic segmentation-based dosimetry, versus 99mTc-MAA segmentation, results in lower absorbed doses with superior reproducibility. Higher volume compartments, such as normal tissue versus tumour, exhibit improved reproducibility.Trial registration: NCT03295006.

P24-13: Round Robin Study in Korea on alternative test method for evaluating skin irritation potential of medical devices

P24-13: Round Robin Study in Korea on alternative test method for evaluating skin irritation potential of medical devices

Self-knowledge of perceiver effects: Do people know how positively they tend to view targets relative to other people?

There are stable individual differences in how positive people’s impressions of others tend to be and these perceptual tendencies in turn shape behaviour. Using data from an experimental online photo-rating study (N = 303) and from an in-lab round-robin study (N = 156), we explored whether people have insight into how positive their impressions tend to be compared to others. Results from both studies suggest that people are aware of how positive their impressions tend to be relative to others. We discuss implications of having or lacking this form of self-knowledge.

Round-Robin Interlaboratory Study on Rare-Earth Elements in U.S.-Based Geologic Materials

In a study funded by the U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL), the University of North Dakota (UND) Energy and Environmental Research Center (EERC) performed a first-of-its-kind round-robin interlaboratory study (RRIS) to determine lab-to-lab and method-to-method variability in analyzing the rare earth element (REE) content of domestic resources. Analyses of REEs on eleven different materials were accomplished by the laboratories using four different procedures: ASTM D6357 (Procedure A), ASTM D4503 (Procedure B), an alternate in-house procedure for digestion and REE analysis (Procedure C), and neutron activation analysis (NAA). The results of the RRIS suggest that NAA is the most accurate and reliable method for many of the REEs in these types of materials; however, the method is limited in that it is able to determining only ten of the sixteen REEs. Five of the seven labs reporting data for Procedure A and three of the five labs reporting for Procedure B showed excellent performance in terms of repeatability, reproducibility, agreement with NAA, and SRM recoveries based on AOAC International guidelines on method performance. This indicates that when strictly followed these methods are suitable for REE determination in most materials, although are subject to the overall capabilities and experience of individual laboratories.

Variability and associated uncertainty in image analysis for soiling characterization in solar energy systems

The accumulation of soiling on photovoltaic modules and on the mirrors of concentrating solar power systems causes non-negligible energy losses with economic consequences. These challenges can be mitigated, or even prevented, through appropriate actions if the magnitude of soiling is known. Particle counting analysis is a common procedure to characterize soiling, as it can be easily performed on micrographs of glass coupons or solar devices that have been exposed to the environment. Particle counting does not, however, yield invariant results across institutions. The particle size distribution analysis is affected by the operator of the image analysis software and the methodology utilized. The results of a round-robin study are presented in this work to explore and elucidate the uncertainty related to particle counting and its effect on the characterization of the soiling of glass surfaces used in solar energy conversion systems. An international group of soiling experts analysed the same 8 micrographs using the same open-source ImageJ software package. The variation in the particle analyses results were investigated to identify specimen characteristics with the lowest coefficient of variation (CV) and the least uncertainty among the various operators. The mean particle diameter showed the lowest CV among the investigated characteristics, whereas the number of particles exhibited the largest CV. Additional parameters, such as the fractional area coverage by particles and parameters related to the distribution's shape yielded intermediate CV values. These results can provide insights on the magnitude inter-lab variability and uncertainty for optical and microscope-based soiling monitoring and characterization.

Validation and standardization of SPE and HPLC-UV methods for simultaneous determination of legacy and insensitive munitions

There have been few attempts to consolidate legacy and insensitive munitions analyses. Furthermore, there are no standard methods for insensitive munitions (IM) in tissues, resulting in overlapping methods and supplementary analyses. The goal of the present study was to validate extraction and instrumental methods previously developed and address analytical methodology gaps (missing tissue matrices, combined legacy and IM analysis, and IM compounds). The method encompasses analytes in waters, soils, and tissues. The primary and secondary instrumental methodologies use high performance liquid chromatography-ultraviolet (HPLC-UV) and an alternate LC-mass spectrometry (MS) method, which includes 26 compounds of interest (legacy munitions, IM, IM degradation products, and other munitions compounds). The methods were formally evaluated during a series of double-blind round robin studies including a broad variety of laboratories (Government Department of Defense (DoD), Government non-DoD, ammunition manufacturing, commercial, and academic). The results of these round robin studies were gathered to generate recovery ranges for each of the 26 compounds in each of the matrices. The recovery ranges were subsequently compared with existing recovery ranges for standard explosives analysis, United States Environmental Protection Agency (USEPA) 8330B. The validation study reveals a capable method, which reduces analysis time for IM and legacy munitions analyses.

Strength of additively manufactured alumina with different debinding and sintering heat treatments

AbstractLithography‐based ceramic manufacturing (LCM) utilizes slurries with low solids loading, which makes pressureless sintering to full density especially difficult. A further compounding issue in sintering to full density and establishing structure–property–processing relationships for LCM alumina is the fact that the current literature lacks consensus on heat treatments to achieve full densities. Treatment specifics that are recorded are frequently ambiguous and insufficiently detailed. In this work, temperatures and times for debinding and sintering schedules were varied to characterize the influence of heat treatment parameters on density, microstructure, and flexural strength of high‐purity, LCM‐formed alumina. Removing the bisque‐fire from debinding and fine‐tuning sintering parameters produced parts with full densities, high flexural strengths, and Weibull moduli that match or exceed the values documented in a round robin study of traditionally processed alumina.