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OBJECTIVE: To assess the impact of an intervention package on the prescription of antibiotic and subsequently the rate of clinical recovery for non-severe acute febrile illnesses at primary health centers. METHODS: Patients over 6 months of age presenting to primary health care centres with fever or history of fever within the past 7 days were randomized to receive either the intervention package constituted of point-of-care tests including COVID-19 antigen tests, a diagnostic algorithm and training and communication packages, or the standard practice. The primary outcomes were antibiotic prescriptions at Day 0 (D0) and the clinical recovery at Day 7 (D7). Secondary outcomes were non-adherence of participants and parents/caregivers to prescriptions, health workers' non-adherence to the algorithm, and the safety of the intervention. RESULTS: A total of 1098 patients were enrolled. 551 (50.2%) were randomized to receive the intervention versus 547 (49.8%) received standard care. 1054 (96.0%) completed follow-up and all of them recovered at D7 in both arms. The proportion of patients with antibiotic prescriptions at D0 were 33.2% (183/551) in the intervention arm versus 58.1% (318/547) under standard care, risk difference (RD) -24.9 (95% CI -30.6 to -19.2, p < 0.001), corresponding to one more antibiotic saved every four (95% CI: 3 to 5) consultations. This reduction was also statistically significant in children from 6 to 59 months (RD -34.5; 95% CI -41.7 to -27.3; p < 0.001), patients over 18 years (RD -35.9; 95%CI -58.5 to -13.4; p = 0.002), patients with negative malaria test (RD -46.9; 95% CI -53.9 to -39.8; p < 0.001), those with a respiratory diagnosis (RD -48.9; 95% CI -56.9 to -41.0, p < 0.001) and those not vaccinated against COVID-19 (-24.8% 95%CI -30.7 to -18.9, p-value: <0.001). A significant reduction in non-adherence to prescription by patients was reported (RD -7.1; 95% CI -10.9 to -3.3; p < 0.001). CONCLUSION: The intervention was associated with significant reductions of antibiotic prescriptions and non-adherence, chiefly among patients with non-malaria fever, those with respiratory symptoms and children below 5 years of age. The addition of COVID-19 testing did not have a major impact on antibiotic use at primary health centers. TRIAL REGISTRATION: Clinitrial.gov; NCT04081051 registered on 06/09/2019.
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Algoritmos , Antibacterianos , COVID-19 , Febre , Atenção Primária à Saúde , Humanos , Antibacterianos/uso terapêutico , Feminino , Masculino , COVID-19/diagnóstico , Pré-Escolar , Lactente , Burkina Faso , Febre/tratamento farmacológico , Criança , Testes Imediatos , SARS-CoV-2 , Adolescente , Adulto , Sistemas Automatizados de Assistência Junto ao LeitoRESUMO
Wnts are lipid-modified glycoproteins that play key roles in both embryonic development and adult homeostasis. Wnt signaling is dysregulated in many cancers and preclinical data shows that targeting Wnt biosynthesis and secretion can be effective in Wnt-addicted cancers. An integral membrane protein known as Wntless (WLS/Evi) is essential for Wnt secretion. However, WLS remains undrugged thus far. The cryo-EM structure of WLS in complex with WNT8A shows that WLS has a druggable G-protein coupled receptor (GPCR) domain. Using Active Learning/Glide, we performed an ultra-large scale virtual screening from Enamine's REAL 350/3 Lead-Like library containing nearly 500 million compounds. 68 hits were examined after on-demand synthesis in cell-based Wnt reporter and other functional assays. ETC-451 emerged as a potential first-in-class WLS inhibitor. ETC-451 blocked WLS-WNT3A interaction and decreased Wnt-addicted pancreatic cancer cell line proliferation. The current hit provides a starting chemical scaffold for further structure or ligand-based drug discovery targeting WLS.
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This study focuses on the design and characterization of binary nanoparticle superlattices: Two differently sized, supercharged protein nanocages are used to create a matrix for nanoparticle arrangement. We have previously established the assembly of protein nanocages of the same size. Here, we present another approach for multicomponent biohybrid material synthesis by successfully assembling two differently sized supercharged protein nanocages with different symmetries. Typically, the ordered assembly of objects with nonmatching symmetry is challenging, but our electrostatic-based approach overcomes the symmetry mismatch by exploiting electrostatic interactions between oppositely charged cages. Moreover, our study showcases the use of nanoparticles as a contrast enhancer in an elegant way to gain insights into the structural details of crystalline biohybrid materials. The assembled materials were characterized with various methods, including transmission electron microscopy (TEM) and single-crystal small-angle X-ray diffraction (SC-SAXD). We employed cryo-plasma-focused ion beam milling (cryo-PFIB) to prepare lamellae for the investigation of nanoparticle sublattices via electron cryo-tomography. Importantly, we refined superlattice structure data obtained from single-crystal SAXD experiments, providing conclusive evidence of the final assembly type. Our findings highlight the versatility of protein nanocages for creating distinctive types of binary superlattices. Because the nanoparticles do not influence the type of assembly, protein cage matrices can combine various nanoparticles in the solid state. This study not only contributes to the expanding repertoire of nanoparticle assembly methods but also demonstrates the power of advanced characterization techniques in elucidating the structural intricacies of these biohybrid materials.
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Titanium dioxide (TiO2) shows significant potential as a self-cleaning material to inactivate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and prevent virus transmission. This study provides insights into the impact of UV-A light on the photocatalytic inactivation of adsorbed SARS-CoV-2 virus-like particles (VLPs) on a TiO2 surface at the molecular and atomic levels. X-ray photoelectron spectroscopy, combined with density functional theory calculations, reveals that spike proteins can adsorb on TiO2 predominantly via their amine and amide functional groups in their amino acids blocks. We employ atomic force microscopy and grazing-incidence small-angle X-ray scattering (GISAXS) to investigate the molecular-scale morphological changes during the inactivation of VLPs on TiO2 under light irradiation. Notably, in situ measurements reveal photoinduced morphological changes of VLPs, resulting in increased particle diameters. These results suggest that the denaturation of structural proteins induced by UV irradiation and oxidation of the virus structure through photocatalytic reactions can take place on the TiO2 surface. The in situ GISAXS measurements under an N2 atmosphere reveal that the virus morphology remains intact under UV light. This provides evidence that the presence of both oxygen and UV light is necessary to initiate photocatalytic reactions on the surface and subsequently inactivate the adsorbed viruses. The chemical insights into the virus inactivation process obtained in this study contribute significantly to the development of solid materials for the inactivation of enveloped viruses.
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SARS-CoV-2 , Titânio , Raios Ultravioleta , Titânio/química , Titânio/efeitos da radiação , SARS-CoV-2/efeitos da radiação , SARS-CoV-2/química , Inativação de Vírus/efeitos da radiação , Inativação de Vírus/efeitos dos fármacos , Humanos , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , COVID-19/virologia , COVID-19/prevenção & controle , Adsorção , Propriedades de SuperfícieRESUMO
AIMS/HYPOTHESIS: Stem cell-derived islets (SC-islets) are being used as cell replacement therapy for insulin-dependent diabetes. Non-invasive long-term monitoring methods for SC-islet grafts, which are needed to detect misguided differentiation in vivo and to optimise their therapeutic effectiveness, are lacking. Positron emission tomography (PET) has been used to monitor transplanted primary islets. We therefore aimed to apply PET as a non-invasive monitoring method for SC-islet grafts. METHODS: We implanted different doses of human SC-islets, SC-islets derived using an older protocol or a state-of-the-art protocol and SC-islets genetically rendered hyper- or hypoactive into mouse calf muscle to yield different kinds of grafts. We followed the grafts with PET using two tracers, glucagon-like peptide 1 receptor-binding [18F]F-dibenzocyclooctyne-exendin-4 ([18F]exendin) and the dopamine precursor 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]FDOPA), for 5 months, followed by histological assessment of graft size and composition. Additionally, we implanted a kidney subcapsular cohort with different SC-islet doses to assess the connection between C-peptide and stem cell-derived beta cell (SC-beta cell) mass. RESULTS: Small but pure and large but impure grafts were derived from SC-islets. PET imaging allowed detection of SC-islet grafts even <1 mm3 in size, [18F]exendin having a better detection rate than [18F]FDOPA (69% vs 44%, <1 mm3; 96% vs 85%, >1 mm3). Graft volume quantified with [18F]exendin (r2=0.91) and [18F]FDOPA (r2=0.86) strongly correlated with actual graft volume. [18F]exendin PET delineated large cystic structures and its uptake correlated with graft SC-beta cell proportion (r2=0.68). The performance of neither tracer was affected by SC-islet graft hyper- or hypoactivity. C-peptide measurements under fasted or glucose-stimulated conditions did not correlate with SC-islet graft volume or SC-beta cell mass, with C-peptide under hypoglycaemia having a weak correlation with SC-beta cell mass (r2=0.52). CONCLUSIONS/INTERPRETATION: [18F]exendin and [18F]FDOPA PET enable non-invasive assessment of SC-islet graft size and aspects of graft composition. These methods could be leveraged for optimising SC-islet cell replacement therapy in diabetes.
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BACKGROUNDFeatures of consumptive coagulopathy and thromboinflammation are prominent in cerebral malaria (CM). We hypothesized that thrombogenic autoantibodies contribute to a procoagulant state in CM.METHODSPlasma from children with uncomplicated malaria (UM) (n = 124) and CM (n = 136) was analyzed by ELISA for a panel of 8 autoantibodies including anti-platelet factor 4/polyanion (anti-PF4/P), anti-phospholipid, anti-phosphatidylserine, anti-myeloperoxidase, anti-proteinase 3, anti-dsDNA, anti-ß-2-glycoprotein I, and anti-cardiolipin. Plasma samples from individuals with nonmalarial coma (NMC) (n = 49) and healthy controls (HCs) (n = 56) were assayed for comparison. Associations with clinical and immune biomarkers were determined using univariate and logistic regression analyses.RESULTSMedian anti-PF4/P and anti-PS IgG levels were elevated in individuals with malaria infection relative to levels in HCs (P < 0.001) and patients with NMC (PF4/P: P < 0.001). Anti-PF4/P IgG levels were elevated in children with CM (median = 0.27, IQR: 0.19-0.41) compared with those with UM (median = 0.19, IQR: 0.14-0.22, P < 0.0001). Anti-PS IgG levels did not differ between patients with UM and those with CM (P = 0.39). When patients with CM were stratified by malaria retinopathy (Ret) status, the levels of anti-PF4/P IgG correlated negatively with the peripheral platelet count in patients with Ret+ CM (Spearman's rho [Rs] = 0.201, P = 0.04) and associated positively with mortality (OR = 15.2, 95% CI: 1.02-275, P = 0.048). Plasma from patients with CM induced greater platelet activation in an ex vivo assay relative to plasma from patients with UM (P = 0.02), and the observed platelet activation was associated with anti-PF4/P IgG levels (Rs= 0.293, P = 0.035).CONCLUSIONSThrombosis mediated by elevated anti-PF4/P autoantibodies may be one mechanism contributing to the clinical complications of CM.
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Autoanticorpos , Malária Cerebral , Fator Plaquetário 4 , Humanos , Malária Cerebral/imunologia , Malária Cerebral/sangue , Autoanticorpos/sangue , Autoanticorpos/imunologia , Feminino , Masculino , Fator Plaquetário 4/imunologia , Fator Plaquetário 4/sangue , Criança , Pré-Escolar , Lactente , Polieletrólitos , Trombose/imunologia , Trombose/sangueRESUMO
BACKGROUND: P2X7 receptor has emerged as a potentially superior PET imaging marker to TSPO, the gold standard for imaging glial reactivity. [11C]SMW139 is the most recently developed radiotracer to image P2X7 receptor. The aim of this study was to image reactive glia in the APP/PS1-21 transgenic (TG) mouse model of Aß deposition longitudinally using [11C]SMW139 targeting P2X7 receptor and to compare tracer uptake to that of [18F]F-DPA targeting TSPO at the final imaging time point. TG and wild type (WT) mice underwent longitudinal in vivo PET imaging using [11C]SMW139 at 5, 8, 11, and 14 months, followed by [18F]F-DPA PET scan only at 14 months. In vivo imaging results were verified by ex vivo brain autoradiography, immunohistochemical staining, and analysis of [11C]SMW139 unmetabolized fraction in TG and WT mice. RESULTS: Longitudinal change in [11C]SMW139 standardized uptake values (SUVs) showed no statistically significant increase in the neocortex and hippocampus of TG or WT mice, which was consistent with findings from ex vivo brain autoradiography. Significantly higher [18F]F-DPA SUVs were observed in brain regions of TG compared to WT mice. Quantified P2X7-positive staining in the cortex and thalamus of TG mice showed a minor increase in receptor expression with ageing, while TSPO-positive staining in the same regions showed a more robust increase in expression in TG mice as they aged. [11C]SMW139 was rapidly metabolized in mice, with 33% of unmetabolized fraction in plasma and 29% in brain homogenates 30 min after injection. CONCLUSIONS: [11C]SMW139, which has a lower affinity for the rodent P2X7 receptor than the human version of the receptor, was unable to image the low expression of P2X7 receptor in the APP/PS1-21 mouse model. Additionally, the rapid metabolism of [11C]SMW139 in mice and the presence of several brain-penetrating radiometabolites significantly impacted the analysis of in vivo PET signal of the tracer. Finally, [18F]F-DPA targeting TSPO was more suitable for imaging reactive glia and neuroinflammatory processes in the APP/PS1-21 mouse model, based on the findings presented in this study and previous studies with this mouse model.
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Spatiotemporal soil heterogeneity and the resulting edaphic stress cycles can be decisive for crop growth. However, our understanding of the acclimative value of root responses to heterogeneous soil conditions remains limited. We outline a framework to evaluate the acclimative value of root responses that distinguishes between stress responses that are persistent and reversible upon stress release, termed 'plasticity' and 'elasticity', respectively. Using energy balances, we provide theoretical evidence that the advantage of plasticity over elasticity increases with the number of edaphic stress cycles and if responses lead to comparatively high energy gains. Our framework provides a conceptual basis for assessing the acclimative value of root responses to soil heterogeneity and can catalyse research on crop adaptations to heterogeneous belowground environments.
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Raízes de Plantas , Solo , Raízes de Plantas/fisiologia , Raízes de Plantas/crescimento & desenvolvimento , Aclimatação/fisiologia , Elasticidade , Produtos Agrícolas/fisiologia , Produtos Agrícolas/crescimento & desenvolvimento , Estresse Fisiológico/fisiologiaRESUMO
This paper describes the investigation of synthetic cannabinoid news psychoactive substances in drug rehabilitation patients in the UAE. This represents the latest data for such drugs in the Gulf region.
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Hypoxic-ischemic encephalopathy due to insufficient oxygen delivery to brain tissue is a leading cause of death or severe morbidity in neonates. The early recognition of the most severely affected individuals remains a clinical challenge. We hypothesized that hypoxic-ischemic injury can be detected using PET radiotracers for hypoxia ([18F]EF5), glucose metabolism ([18F]FDG), and inflammation ([18F]F-DPA). METHODS: A preclinical model of neonatal hypoxic-ischemic brain injury was made in 9-d-old rat pups by permanent ligation of the left common carotid artery followed by hypoxia (8% oxygen and 92% nitrogen) for 120 min. In vivo PET imaging was performed immediately after injury induction or at different timepoints up to 21 d later. After imaging, ex vivo brain autoradiography was performed. Brain sections were stained with cresyl violet to evaluate the extent of the brain injury and to correlate it with [18F]FDG uptake. RESULTS: PET imaging revealed that all three of the radiotracers tested had significant uptake in the injured brain hemisphere. Ex vivo autoradiography revealed high [18F]EF5 uptake in the hypoxic hemisphere immediately after the injury (P < 0.0001), decreasing to baseline even 1 d postinjury. [18F]FDG uptake was highest in the injured hemisphere on the day of injury (P < 0.0001), whereas [18F]F-DPA uptake was evident after 4 d (P = 0.029), peaking 7 d postinjury (P < 0.0001), and remained significant 21 d after the injury. Targeted evaluation demonstrated that [18F]FDG uptake measured by in vivo imaging 1 d postinjury correlated positively with the brain volume loss detected 21 d later (r = 0.72, P = 0.028). CONCLUSION: Neonatal hypoxic-ischemic brain injury can be detected using PET imaging. Different types of radiotracers illustrate distinct phases of hypoxic brain damage. PET may be a new useful technique, worthy of being explored for clinical use, to predict and evaluate the course of the injury.
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Lesões Encefálicas , Hipóxia-Isquemia Encefálica , Ratos , Animais , Hipóxia-Isquemia Encefálica/diagnóstico por imagem , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons/métodos , Encéfalo/diagnóstico por imagem , Modelos Animais de Doenças , Oxigênio , Animais Recém-NascidosRESUMO
Study Objectives: Observational studies link untreated obstructive sleep apnea (OSA) with adverse outcomes in chronic obstructive pulmonary disease (COPD). The first step in addressing OSA is a clinical assessment. However, given competing demands and a lack of high-quality evidence, it is unclear how often such assessments occur. We explored the documentation of OSA assessment among patients with COPD in primary care, and the patient and provider characteristics associated with these assessments. Methods: We conducted a cross-sectional study of patients with clinically diagnosed COPD at 2 primary care practices. We abstracted charts to determine whether providers assessed OSA, defined as documentation of symptoms, treatment, or a referral to sleep medicine. We performed multivariable mixed-effects logistic regression to assess the associations of patient and provider characteristics with OSA assessment. Results: Among 641 patients with clinically diagnosed COPD, 146 (23%) had OSA assessed over a 1-year period. Positive associations with OSA assessment included body mass index ≥ 30 (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.8-7.0), pulmonary subspecialist visits (OR 3.9, 95%CI 2.4-6.3), and a prior sleep study demonstrating OSA documented within the electronic medical record (OR 18.0, 95%CI 9.0-35.8). Notably, patients identifying as Black were less likely to have OSA assessed than those identifying as White (OR 0.5, 95%CI 0.2-0.9). Conclusions: Providers document an assessment of OSA among a quarter of patients with COPD. Our findings highlight the importance of future work to rigorously test the impact of assessment on important health outcomes. Our findings also reinforce that additional strategies are needed to improve the equitable delivery of care.
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Linking structure to mechanical and elastic properties is a major concern for the development of novel electroactive materials. This work reports on the potential-induced changes in thickness and Young modulus of a substrate supported, perchlorate doped polypyrrole thin film (<100 nm) investigated with electrochemical atomic force microscopy (AFM) under in situ conditions. This was accomplished by nanomechanical mapping of potentiodynamically electropolymerized polypyrrole film in electrolyte solution with AFM during redox cycling. The polypyrrole film thickness and Young modulus follow the electrical potential nearly linearly, increasing due to solvent and ion influx as the film is oxidized, and decreasing during reduction. Our measurements also confirm the presence of a potential-independent, passive swelling which is accompanied by softening of the film, likely caused by osmotic effects. Additionally, the heterogeneous distribution of the Young modulus can be directly traced to the typical nodular surface topography of polypyrrole, with the top of the nodular area possessing lower modulus, thus highlighting the complex relationship between topography and elastic properties.
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Introduction: Patients with neuropathic pain (NP) report a higher impairment of quality of life and sleep than patients with chronic pain without neuropathic characteristics. These include somatosensory peculiarities like allodynia, a surrogate marker for central sensitization. Objectives: This study aimed to investigate the relation between symptoms of central sensitization and sleep disturbances in patients with NP. Methods: Within this cross-sectional study, data sets of 3339 patients with chronic NP syndromes (painful diabetic polyneuropathy, n = 543; postherpetic neuralgia, n = 1480) or complex regional pain syndromes (CRPS, n = 1316) were analyzed. Neuropathic pain symptoms were assessed with the painDETECT questionnaire (PD-Q), depression with the Patient Health Questionnaire-9, and sleep impairment with items of the Medical Outcomes Study Sleep Scale in 4 subscales. The association of demographic/clinical data, somatosensory phenotype, depression, and pain intensity with sleep impairment was assessed by unadjusted Spearman correlation analyses and multivariable regression analyses. Results: Sleep impairment was observed in all pain aetiologies although with some significant differences in the single sleep items. The intensity of the individual PD-Q items differed to some extent between the 3 pain entities, whereas the PD-Q sum score was similar. Thermal hyperalgesia and burning assessed by the PD-Q were significantly associated with sleep disturbance, adequacy, and quantity but not with sleep somnolence. Only depression and self-reported allodynia had a significant relation to all 4 sleep elements. Conclusion: Beside depression, allodynia as a surrogate marker hints to a possible impact of central sensitization on the sleep disruption of patients with NP.
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Pattern fabrication by self-assembly of diblock copolymers is of significant interest due to the simplicity in fabricating complex structures. In particular, polystyrene-block-poly-4-vinylpyridine (PS-b-P4VP) is a fascinating base material as it forms an ordered micellar structure on silicon surfaces. In this work, silver (Ag) is applied using direct current magnetron sputter deposition and high-power impulse magnetron sputter deposition on an ordered micellar PS-b-P4VP layer. The fabricated hybrid materials are structurally analyzed by field emission scanning electron microscopy, atomic force microscopy, and grazing incidence small angle X-ray scattering. When applying simple aqueous posttreatment, the pattern is stable and reinforced by Ag clusters, making micellar PS-b-P4VP ordered layers ideal candidates for lithography.
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It is important for external quality assessment materials (EQAMs) to be commutable with clinical samples; i.e., they should behave like clinical samples when measured using end-user clinical laboratory in vitro diagnostic medical devices (IVD-MDs). Using commutable EQAMs makes it possible to evaluate metrological traceability and/or equivalence of results between IVD-MDs. The criterion for assessing commutability of an EQAM between 2 IVD-MDs is that its result should be within the prediction interval limits based on the statistical distribution of the clinical sample results from the 2 IVD-MDs being compared. The width of the prediction interval is, among other things, dependent on the analytical performance characteristics of the IVD-MDs. A presupposition for using this criterion is that the differences in nonselectivity between the 2 IVD-MDs being compared are acceptable. An acceptable difference in nonselectivity should be small relative to the analytical performance specifications used in the external quality assessment scheme. The acceptable difference in nonselectivity is used to modify the prediction interval criterion for commutability assessment. The present report provides recommendations on how to establish a criterion for acceptable commutability for EQAMS, establish the difference in nonselectivity that can be accepted between IVD-MDs, and perform a commutability assessment. The report also contains examples for performing a commutability assessment of EQAMs.
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Serviços de Laboratório Clínico , Ensaio de Proficiência Laboratorial , Humanos , Padrões de Referência , Kit de Reagentes para DiagnósticoRESUMO
A secondary higher-order calibrator is required to be commutable with clinical samples to be suitable for use in the calibration hierarchy of an end-user clinical laboratory in vitro diagnostic medical device (IVD-MD). Commutability is a property of a reference material that means results for a reference material and for clinical samples have the same numeric relationship, within specified limits, across the measurement procedures for which the reference material is intended to be used. Procedures for assessing commutability have been described in the literature. This report provides recommendations for establishing a quantitative criterion to assess the commutability of a certified reference material (CRM). The criterion is the maximum allowable noncommutability bias (MANCB) that allows a CRM to be used as a calibrator in a calibration hierarchy for an IVD-MD without exceeding the maximum allowable combined standard uncertainty for a clinical sample result (umaxCS). Consequently, the MANCB is derived as a fraction of the umaxCS for the measurand. The suitability of an MANCB for practical use in a commutability assessment is determined by estimating the number of measurements of clinical samples and CRMs required based on the precision performance and nonselectivity for the measurand of the measurement procedures in the assessment. Guidance is also provided for evaluating indeterminate commutability conclusions and how to report results of a commutability assessment.
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To promote diversity in the STEM workforce, undergraduate research training programs incorporating a variety of intervention strategies have been developed to support students from historically underrepresented backgrounds in overcoming numerous systemic barriers to pursuing careers in science. However, relatively little research has focused on how students experience and value these interventions and the ways in which the interventions support student success. The current study analyzed qualitative interviews from participants (n=15) in a comprehensive research training program for undergraduates historically underrepresented in biomedical research to investigate the student perspective on how specific program components address barriers and support their research training, academic progress, and career preparation. Findings indicated that students benefit from authentic research experiences, mentoring, supplemental curriculum, financial assistance, and a supportive program environment. Participants described how the program helped them address financial concerns, navigate academic and career choices, build science identity and efficacy, and feel a sense of belonging within a caring community. The study highlights how multi-faceted research training programs offering a variety of supports can contribute to student retention and development according to the needs and circumstances of individual students.
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Various initiatives for undergraduates from historically underrepresented backgrounds attempt to address disparities in the completion of science, technology, engineering, mathematics (STEM) degrees and the pursuit of careers in scientific research. Intensive research training programs for historically underrepresented undergraduates may include multiple components, such as authentic research experiences, advising and mentoring, supplemental curriculum, and financial assistance. Following comprehensive support during program participation, the post-program transition may present a vulnerable period in students' career trajectories. This study used a community-based participatory research (CBPR) approach to investigate the experiences of students completing an intensive research training program to understand and develop recommendations for the post-program transition process. As a team of program alumni, academic researchers, and program staff, we developed, conducted, and analyzed semi-structured, open-ended interviews of recent program alumni and students approaching program completion (n=11; 55% female, 55% non-White). Applying thematic analysis at semantic and latent levels through a critical paradigm revealed the transition as a bittersweet experience, with feelings of pride and accomplishment mixed with sadness and anxiety. Findings also suggested the transition is described as a narrative influenced by preceding program experiences and adaptations. Financial concerns were prominent, and specific barriers and facilitators of successful transition included: aligned mentoring, negotiation of continued research employment, consideration of culture, planning for next steps, and engagement with the scholar community. Collaboratively, we developed recommendations for program improvements potentially relevant to similarly intensive STEM diversity programs. We also highlight the value of a CBPR approach that includes students equitably as co-researchers in program research and evaluation.
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Corrosion is the main factor limiting the lifetime of metallic materials, and a fundamental understanding of the governing mechanism and surface processes is difficult to achieve since the thin oxide films at the metal-liquid interface governing passivity are notoriously challenging to study. In this work, a combination of synchrotron-based techniques and electrochemical methods is used to investigate the passive film breakdown of a Ni-Cr-Mo alloy, which is used in many industrial applications. This alloy is found to be active toward oxygen evolution reaction (OER), and the OER onset coincides with the loss of passivity and severe metal dissolution. The OER mechanism involves the oxidation of Mo4+ sites in the oxide film to Mo6+ that can be dissolved, which results in passivity breakdown. This is fundamentally different from typical transpassive breakdown of Cr-containing alloys where Cr6+ is postulated to be dissolved at high anodic potentials, which is not observed here. At high current densities, OER also leads to acidification of the solution near the surface, further triggering metal dissolution. The OER plays an important role in the mechanism of passivity breakdown of Ni-Cr-Mo alloys due to their catalytic activity, and this effect needs to be considered when studying the corrosion of catalytically active alloys.