Comparison of Commonly Carried Liquids Against Commercial Ultrasound Gel for Use in the Backcountry Setting.

INTRODUCTION: Point-of-care ultrasound (POCUS) is utilized in austere environments because it is lightweight, durable, battery powered, and portable. In austere settings, weight and space constraints are limitations to carrying dedicated ultrasound gel. Few studies have assessed commonly carried liquids as gel alternatives. The study objective was to assess the suitability of common food and personal care products as ultrasound coupling agents compared with that of commercial gel. METHODS: A noninferiority study compared 9 products to commercial gel. Each substance was independently tested on 2 subjects by 2 sonographers covering 8 standardized ultrasound windows. Clips were recorded, blinded, and independently graded by 2 ultrasound fellowship-trained physicians on the ability to make clinical decisions and technical details, including contrast, resolution, and artifact. A 20% noninferiority margin was set, which correlates to levels considered to be of reliably sufficient quality by American College of Emergency Physicians' guidelines. The substances included water, soap, shampoo, olive oil, energy gel, maple syrup, hand sanitizer, sunscreen, and lotion. RESULTS: A total of 300 of 318 (94%) clips met the primary endpoint of adequacy to make a clinical decision. All media, except sunscreen, were noninferior to commercial gel in the ability to make a clinical decision (α=0.05). In terms of secondary outcomes, resolution, artifact, and contrast, all substances were noninferior to commercial gel (α=0.05). The sonographers concluded that all gel alternatives' usability performed similarly to commercial gel, with the exception of energy gel. CONCLUSIONS: Of the 9 substances tested, 8 were noninferior to commercial gels for clinical decisions. Our study indicates that several POCUS gel substitutes are serviceable to produce clinically adequate images.

Comparison of five different methodologies for evaluating ankle-foot orthosis stiffness.

BACKGROUND: The mechanical properties of an ankle-foot orthosis (AFO) play an important role in the gait mechanics of the end user. However, testing methodologies for evaluating these mechanical properties are not standardized. The purpose of this study was to compare five different evaluation frameworks to assess AFO stiffness. METHOD: The same 13 carbon composite AFOs were tested with five different methods. Four previously reported custom test fixtures (the BRUCE, KST, SMApp, and EMPIRE) rotated an AFO into dorsiflexion about a defined axis in the sagittal plane. The fifth method involved quasi-static deflection of AFOs into dorsiflexion by hanging weights (HW) from the footplate. AFO rotational stiffness was calculated as the linear fit of the AFO resistive torque and angular deflection. Differences between methods were assessed using descriptive statistics and a repeated measures Friedman with post-hoc Bonferroni-Holm adjusted Wilcoxon signed-rank tests. RESULTS: There were significant differences in measured AFO stiffnesses between test methods. Specifically, the BRUCE and HW methods measured lower stiffness than both the EMPIRE and the KST. Stiffnesses measured by the SMApp were not significantly different than any test method. Stiffnesses were lowest in the HW method, where motion was not constrained to a single plane. The median difference in absolute AFO stiffness across methods was 1.03 Nm/deg with a range of [0.40 to 2.35] Nm/deg. The median relative percent difference, measured as the range of measured stiffness from the five methods over the average measured stiffness was 62% [range 13% to 156%]. When the HW method was excluded, the four previously reported test fixtures produced a median difference in absolute AFO stiffness of 0.52 [range 0.38 to 2.17] Nm/deg with a relative percent difference between the methods of 27% [range 13% to 89%]. CONCLUSIONS: This study demonstrates the importance of developing mechanical testing standards, similar to those that exist for lower limb prosthetics. Lacking standardization, differences in methodology can result in large differences in measured stiffness, particularly for different constraints on motion. Non-uniform measurement practices may limit the clinical utility of AFO stiffness as a metric in AFO prescription and future research.

Evidence for Test Validation: A Guide for Practitioners / Evidencias Sobre la Validación de los Tests: una Guía Práctica

Background: Validity is a core topic in educational and psychological assessment. Although there are many available resources describing the concept of validity, sources of validity evidence, and suggestions about how to obtain validity evidence; there is little guidance providing specific instructions for planning and carrying out validation studies. Method: In this paper we describe (a) the fundamental principles underlying test validity, (b) the process of validation, and (c) practical guidance for practitioners to plan and carry out sufficient validity research to support the use of a test for its intended purposes. Results: We first define validity, describe sources of validity evidence, and provide examples where each of these sources are addressed. Then, we describe a validation agenda describing steps and tasks for planning and developing validation studies. Conclusions: Finally, we discuss the importance of addressing validation studies from a comprehensive approach.(AU)

Antecedentes: La validez es un tema central en la evaluación psicológica y educativa. A pesar de que la literature disponible recoge numerosos recursos en los que se describe el concepto de validez, las fuentes de evidencia y se aportan sugerencias sobre cómo obtener evidencias de validez, apenas existen guías que proporcionen instrucciones específicas para planificar y desarrollar estudios de validación. Método: El presente artículo describe (a) los principios fundamentales en los que se sustenta la validez de los test, (b) el proceso de validación, y (c) una guía práctica para planificar y recoger evidencias de validez que apoyen el uso de un test para alcanzar el objetivo previsto. Resultados: En primer lugar, se describe el concepto de validez y las fuentes de evidencia, aportando ejemplos específicos donde se abordan cada una de ellas. A continuación, se describe una agenda de validación en la que se enumeran los pasos y tareas necesarios para planificar y completar un estudio de validación. Conclusiones: Finalmente, se discute la relevancia de adoptar una aproximación comprehensiva al abordar estudios de validación.(AU)

The performance of gelling fibre wound dressings under clinically relevant robotic laboratory tests.

The effectiveness of wound dressing performance in exudate management is commonly gauged in simple, non-realistic laboratory setups, typically, where dressing specimens are submersed in vessels containing aqueous solutions, rather than by means of clinically relevant test configurations. Specifically, two key fluid-structure interaction concepts: sorptivity-the ability of wound dressings to transfer exudate, including viscous fluids, away from the wound bed by capillary action and durability-the capacity of dressings to maintain their structural integrity over time and particularly, at removal events, have not been properly addressed in existing test protocols. The present article reviews our recent published research concerning the development of clinically relevant testing methods for wound dressings, focussing on the clinical relevance of the tests as well as on the standardisation and automation of laboratory measurements of dressing performance. A second objective of this work was to compile the experimental results characterising the performance of gelling fibre dressings, which were acquired using advanced testing methods, to demonstrate differences across products that apparently belong to the same "gelling fibre" family but differ remarkably in materials, structure and composition and, thereby, in performance.

Fluid management and strength postsimulated use of primary and secondary dressings for treating diabetic foot ulcers: Robotic phantom studies.

Non-offloaded diabetic heel ulcers and the wound dressings used to treat them may be subjected to considerable bodyweight forces. A novel robotic foot phantom with a diabetic heel ulcer was designed and constructed to test the combined performances of applied primary and secondary dressings, in simulated non-offloaded (standing) and offloaded (supine) postures. We specifically compared the performances of the primary Exufiber dressing (Mölnlycke Health Care) combined with the secondary Mepilex Border Flex dressing (Mölnlycke) against a corresponding pair from an alternative manufacturer. Fluid retention and distribution between the primary and secondary dressings of each pair were determined using weight tests, and mechanical strength of the primary dressings was further measured postsimulated use through tensile testing. The Exufiber and Mepilex Border Flex pair performed similarly in the two simulated postures (retention = ~97%), whereas the comparator pair exhibited a 13%-decrease in retention for a supine to standing transition. Furthermore, the Exufiber dressing delivered up to 2-times more fluid to its paired secondary dressing and endured 1.7-times greater strain energy than the corresponding primary dressing before failure occurred. The present robotic foot phantom and associated methods are versatile and suitable for testing any dressing, in consideration of the relevant clinical factors and practice.

Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities.

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from "bench to bedside", fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

Improving the State-of-the-Art in Flow Measurements for Large-Scale Oxygen Consumption Calorimetry.

The accuracy of the exhaust flow measurement contributes significantly to the uncertainty of calorimetry measurements for large fire testing. Less than ideal flow characteristics such as skewed velocity distributions are typical of these large-scale flows and make it difficult to achieve the desired measurement accuracy. Consensus standards for fire testing recommend either bi-directional probes or orifice plates to determine exhaust flow. Both have limited accuracy in the presence of less than ideal flow conditions. Averaging pitot probes are an off-the-shelf technology widely used to monitor flows for industrial processes. They have been utilized in a system of large fire calorimeters to demonstrate differences of less than 5% between heat release rate measurements by oxygen consumption calorimetry and the theoretical heat output from a gas burner. Differences exceeded 5% for a small set of conditions but were still less than 10%. Both levels of agreement are within the confirmation requirements of the consensus standards and were achieved without a system calibration as recommended by the standards. Including this technology as an alternate method to measure exhaust flow would be an improvement to relevant fire testing standards and to the overall accuracy of calorimetry measurements for large fire testing.

A perspective on biomass-derived biofuels: From catalyst design principles to fuel properties.

The hazards to health and the environment associated with the transportation sector include smog, particulate matter, and greenhouse gas emissions. Conversion of lignocellulosic biomass into biofuels has the potential to provide significant amounts of infrastructure-compatible liquid transportation fuels that reduce those hazardous materials. However, the development of these technologies is inefficient, due to: (i) the lack of a priori fuel property consideration, (ii) poor shared vocabulary between process chemists and fuel engineers, and (iii) modern and future engines operating outside the range of traditional autoignition metrics such as octane or cetane numbers. In this perspective, we describe an approach where we follow a "fuel-property first" design methodology with a sequence of (i) identifying the desirable fuel properties for modern engines, (ii) defining molecules capable of delivering those properties, and (iii) designing catalysts and processes that can produce those molecules from a candidate feedstock in a specific conversion process. Computational techniques need to be leveraged to minimize expenses and experimental efforts on low-promise options. This concept is illustrated with current research information available for biomass conversion to fuels via catalytic fast pyrolysis and hydrotreating; outstanding challenges and research tools necessary for a successful outcome are presented.

Guidance for high-stakes testing within pharmacy educational assessment.

BACKGROUND: The term "high-stakes testing" is widely used among pharmacy educators, but the term often seems misused or used incompletely. This Teachable Moments Matter (TMM) focuses on the importance of scientific-rigor when assessing learners' abilities. This article discusses high-stakes testing - what it is and what it is not. This TMM is not meant as an extensive review of the topic. IMPACT: As imperative for ethically-fair high-stakes testing, we will focus on defining and explaining high-stake testing, to include: evidence for validation, development of cut-scores, magnitudes of reliability coefficients, and other reliability measurement tools such as Generalizability Theory and Item-Response Theory. TEACHABLE MOMENT: From our perspectives as educational psychometricians, we hope that this discussion will help foster scientifically-rigorous use and reporting of high-stakes testing in pharmacy education and research.

Comparison of carbon fibre and aluminium materials in the construction of ultralight wheelchairs.

Carbon fibre-reinforced polymers have been used in the sporting goods industry for decades, and wheelchairs have incorporated the material since the late 1980s. There is no independently collected data available on carbon fibre-reinforced polymer wheelchairs' performance on the ANSI/RESNA testing standards, however. This study evaluated three full carbon fibre wheelchair specimens to determine their performance versus similar wheelchairs. Testing determined that while the frames survived more testing cycles than any other wheelchair, the casters and rear tires failed similarly to other devices. Overall, due to the purchase cost, the cost benefit of the tested wheelchair model was similar to aluminium wheelchairs.Implications for rehabilitationCarbon fibre wheelchair construction is a viable alternative to aluminium, titanium, or steel construction, and decreasing costs will continue to improve the benefits of carbon fibre over these modelsCarbon fibre wheelchair found to be more durable than aluminium models, but are also much more expensive. The additional cost may be justified for some users that need the increased durability, howeverIncreased durability will reduce the number of repairs and warranty claims, potentially reducing the burden on a wheelchair user, and also improving their ability to travel and participate in their communityThe low weight of carbon fibre wheelchairs may increase the mobility of some users by allowing them to transfer more easily into and out of vehicles and manoeuvre throughout the environment.

Material failure in dynamic spine implants: are the standardized implant tests before market launch sufficient?

PURPOSE: International Standards Organization (ISO) 12189 and American Society for Testing and Materials F2624 are two standard material specification and test methods for spinal implant devices. The aim of this study was to assess whether the existing and required tests before market launch are sufficient. METHODS: In three prospective studies, patients were treated due to degenerative disease of the lumbar spine or spondylolisthesis with lumbar interbody fusion and dynamic stabilization of the cranial adjacent level. The CD HORIZON BalanC rod and S4 Dynamic rod were implanted in 45 and 11 patients, respectively. RESULTS: A fatigue fracture of the material of the topping off system has been found in five cases (11%) for the group fitted with the CD HORIZON BalanC rod. In the group using the S4 Dynamic rod group, a material failure of the dynamic part was demonstrated in seven patients (64%). All three studies were interrupted due to these results, and a report to the Federal Institute for Drugs and Medical Devices was generated. CONCLUSION: Spinal implants have to be checked by a notified body before market launch. The notified body verifies whether the implants fulfil the requirements of the current standards. These declared studies suggest that the current standards for the testing of load bearing capacity and stand ability of dynamic spine implants might be insufficient. Revised standards depicting sufficient deformation and load pattern have to be developed and counted as a requirement for the market launch of an implant. These slides can be retrieved under Electronic Supplementary Material.

Predictive genetic testing for adult-onset disorders in minors: a critical analysis of the arguments for and against the 2013 ACMG guidelines.

The publication of the ACMG recommendations has reignited the debate over predictive testing for adult-onset disorders in minors. Response has been polarized. With this in mind, we review and critically analyze this debate. First, we identify long-standing inconsistencies between consensus guidelines and clinical practice regarding risk assessment for adult-onset genetic disorders in children using family history and molecular analysis. Second, we discuss the disparate assumptions regarding the nature of whole genome and exome sequencing underlying arguments of both supporters and critics, and the role these assumptions play in the arguments for and against reporting. Third, we suggest that implicit differences regarding the definition of best interests of the child underlie disparate conclusions as to the best interests of children in this context. We conclude by calling for clarity and consensus concerning the central foci of this debate.

Avoiding Systematic Errors in Isometric Squat-Related Studies without Pre-Familiarization by Using Sufficient Numbers of Trials.

There is no scientific evidence in the literature indicating that maximal isometric strength measures can be assessed within 3 trials. We questioned whether the results of isometric squat-related studies in which maximal isometric squat strength (MISS) testing was performed using limited numbers of trials without pre-familiarization might have included systematic errors, especially those resulting from acute learning effects. Forty resistance-trained male participants performed 8 isometric squat trials without pre-familiarization. The highest measures in the first "n" trials (3 ≤ n ≤ 8) of these 8 squats were regarded as MISS obtained using 6 different MISS test methods featuring different numbers of trials (The Best of n Trials Method [BnT]). When B3T and B8T were paired with other methods, high reliability was found between the paired methods in terms of intraclass correlation coefficients (0.93-0.98) and coefficients of variation (3.4-7.0%). The Wilcoxon's signed rank test indicated that MISS obtained using B3T and B8T were lower (p < 0.001) and higher (p < 0.001), respectively, than those obtained using other methods. The Bland-Altman method revealed a lack of agreement between any of the paired methods. Simulation studies illustrated that increasing the number of trials to 9-10 using a relatively large sample size (i.e., ≥ 24) could be an effective means of obtaining the actual MISS values of the participants. The common use of a limited number of trials in MISS tests without pre-familiarization appears to have no solid scientific base. Our findings suggest that the number of trials should be increased in commonly used MISS tests to avoid learning effect-related systematic errors.