scholarly journals Distinct SARS-CoV-2 antibody reactivity patterns in coronavirus convalescent plasma revealed by a coronavirus antigen microarray

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rafael Assis ◽  
Aarti Jain ◽  
Rie Nakajima ◽  
Algis Jasinskas ◽  
Saahir Khan ◽  
...  
Keyword(s):  
Generalized Linear Model ◽  
Neutralization Assay ◽  
Clinical Diagnostics ◽  
Training Set ◽  
Antibody Reactivity ◽  
High Concordance ◽  
And Performance ◽  
The Individual ◽  
Ortho Clinical Diagnostics ◽  
Cutoff Threshold

AbstractA coronavirus antigen microarray (COVAM) was constructed containing 11 SARS-CoV-2, 5 SARS-1, 5 MERS, and 12 seasonal coronavirus recombinant proteins. The array is designed to measure immunoglobulin isotype and subtype levels in serum or plasma samples against each of the individual antigens printed on the array. We probed the COVAM with COVID-19 convalescent plasma (CCP) collected from 99 donors who recovered from a PCR+ confirmed SARS-CoV-2 infection. The results were analyzed using two computational approaches, a generalized linear model (glm) and random forest (RF) prediction model, to classify individual specimens as either Reactive or non-reactive against the SARS-CoV-2 antigens. A training set of 88 pre-COVID-19 specimens (PreCoV) collected in August 2019 and102 positive specimens from SARS-CoV-2 PCR+ confirmed COVID-19 cases was used for these analyses. Results compared with an FDA emergency use authorized (EUA) SARS-CoV2 S1-based total Ig chemiluminescence immunoassay (Ortho Clinical Diagnostics VITROS Anti-SARS-CoV-2 Total, CoV2T) and with a SARS-CoV-2 S1-S2 spike-based pseudovirus micro neutralization assay (SARS-CoV-2 reporter viral particle neutralization titration (RVPNT) showed high concordance between the three assays. Three CCP specimens that were negative by the VITROS CoV2T immunoassay were also negative by both COVAM and the RVPNT assay. Concordance between VITROS CoV2T and COVAM was 96%, VITROS CoV2T and RVPNT 93%, and RVPNT and COVAM 91%. The discordances were all weakly reactive samples near the cutoff threshold of the VITROS CoV2T immunoassay. The multiplex COVAM allows CCP to be grouped according to antibody reactivity patterns against 11 SARS-CoV-2 antigens. Unsupervised K-means analysis, via the gap statistics, as well as hierarchical clustering analysis revealed three main clusters with distinct reactivity intensities and patterns. These patterns were not recapitulated by adjusting the VITROS CoV2T or RVPNT assay thresholds. Plasma classified by COVAM reactivity patterns offers potential to improve CCP therapeutic efficacy CoV2T alone. The use of a SARS-CoV-2 antigen array can qualify CCP for administration as a treatment for acute COVID-19, and interrogate vaccine immunogenicity and performance in preclinical, clinical studies, and routine vaccination to identify antibody responses predictive of protection from infection and disease.

scholarly journals Distinct SARS-CoV-2 Antibody Reactivity Patterns in Coronavirus Convalescent Plasma Revealed by a Coronavirus Antigen Microarray

2020 ◽  
Author(s):  
Rafael Assis ◽  
Aarti Jain ◽  
Rie Nakajima ◽  
Algis Jasinskas ◽  
Saahir Khan ◽  
...  
Keyword(s):  
Neutralization Assay ◽  
Clinical Diagnostics ◽  
Antibody Reactivity ◽  
High Concordance ◽  
And Performance ◽  
The Individual ◽  
Ortho Clinical Diagnostics ◽  
Preclinical And Clinical Studies ◽  
Antibody Levels ◽  
Cutoff Threshold

AbstractA coronavirus antigen microarray (COVAM) was constructed containing 11 SARS-CoV-2, 5 SARS-1, 5 MERS, and 12 seasonal coronavirus recombinant proteins. The array is designed to measure immunoglobulin isotype and subtype levels in serum or plasma samples against each of the individual antigens printed on the array. We probed the COVAM with COVID-19 convalescent plasma (CCP) collected from 99 donors who recovered from a PCR+ confirmed SARS-CoV-2 infection. The results were analyzed using two computational approaches, a generalized linear model (glm) and Random Forest (RF) prediction model, to classify individual specimens as either Reactive or Non-Reactive against the SARS-CoV-2 antigens. A training set of 88 pre-COVID-19 specimens (PreCoV) collected in August 2019 and102 positive specimens from SARS-CoV-2 PCR+ confirmed COVID-19 cases was used for these analyses. Results compared with an FDA emergency use authorized (EUA) SARS-CoV2 S1-based total Ig chemiluminescence immunoassay (Ortho Clinical Diagnostics VITROS® Anti-SARS-CoV-2 Total, CoV2T) and with a SARS-CoV-2 S1-S2 spike-based pseudovirus micro neutralization assay (SARS-CoV-2 reporter viral particle neutralization titration (RVPNT) showed high concordance between the 3 assays. Three CCP specimens that were negative by the VITROS CoV2T immunoassay were also negative by both COVAM and the RVPNT assay. Concordance between VITROS CoV2T and COVAM was 96%, VITROS CoV2T and RVPNT 93%, and RVPNT and COVAM 95%. The discordances were all weakly reactive samples near the cutoff threshold of the VITROS CoV2T immunoassay. The multiplex COVAM allows CCP to be grouped according to antibody reactivity patterns against 11 SARS-CoV-2 antigens. Unsupervised K-means analysis, via the gap statistics, as well as hierarchical clustering analysis revealed 3 main clusters with distinct reactivity intensities and patterns. These patterns were not recapitulated by adjusting the VITROS CoV2T or RVPNT assay thresholds. Plasma classified according to these reactivity patterns may be better associated with CCP treatment efficacy than antibody levels alone. The use of a SARS-CoV-2 antigen array may be useful to qualify CCP for administration as a treatment for acute COVID-19 and to interrogate vaccine immunogenicity and performance in preclinical and clinical studies to understand and recapitulate antibody responses associated with protection from infection and disease.

scholarly journals Performance Evaluation: Four Chemiluminescent SARS-Cov-2 Immunoassays and Rapid-Card Test in Mild Disease and Seroprevalence of SARS CoV-2 in Frontline Healthcare Workers

2021 ◽  
pp. 9-22
Author(s):  
Rasika Setia ◽  
Mitu Dogra ◽  
Anil Handoo ◽  
Gokhula Prasath Thangavel ◽  
Ramesh Yadav ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Modern Medicine ◽  
Clinical Diagnostics ◽  
Clinical Samples ◽  
New Delhi ◽  
Mild Disease ◽  
Increased Risk ◽  
Sample Testing ◽  
And Performance ◽  
Ortho Clinical Diagnostics

Introduction: The COVID-19 pandemic raised a host of challenges to modern medicine. Key amongst these were in diagnostics, as most SARS-CoV-2 assays had been rapidly developed and released under emergency-use authorization with limited validation on clinical samples and secondly, an increased risk of COVID-19 infection to healthcare workers (HCW). There are limited inter-assay comparisons to detect SARS-CoV-2 antibodies in cases with milder symptoms of COVID-19, necessary to evaluate whether assays can detect SARS-CoV-2 antibodies in patients with mild infection.  Aim: Therefore this study aimed to evaluate the performance of four chemiluminescence immunoassays and a rapid immunochromatographic assay in 100 rRT-PCR diagnosed-recovered frontline HCW with milder COVID-19 disease and secondly to evaluate the seroprevalence of SARS-CoV-2 infection in the asymptomatic frontline HCW at a multispeciality hospital in Delhi, India. Study Design: Serum and plasma samples were obtained from 100 rRT-PCR diagnosed-recovered frontline HCWs with mild disease working across the hospital, and performance of four common chemiluminescence immunoassays evaluated. Also samples of 505 asymptomatic, frontline HCWs working in hospital, who had not developed or shown any symptoms of COVID-19 infection to date was collected and the seroprevalence of infection was evaluated. Place and Duration of the Study: A study was conducted at BLK Superspeciality Hospital, New Delhi from September to October 2020. Methods: Four chemiluminescence immunoassays [Abbott SARS-CoV-2 IgG (Nucleocapsid), Roche Elecsys® Anti-SARS-CoV-2 Total (Nucleocapsid), Ortho-Clinical Diagnostics: VITROS Anti-SARS-CoV-2 IgG (Spike) and Anti-SARS-CoV-2 Total (Spike)] and a rapid assay [Medsource Ozone Biomedicals] were evaluated in 100 rRT-PCR diagnosed-recovered frontline HCW with mild disease. Also, seroprevalence was studied in 505 asymptomatic, frontline HCW.  Results: At manufacturers' thresholds, overall sensitivity for Abbott was 71%, Roche 96%, Ortho (both total and IgG(S) 99% and rapid card 56%. Seroprevalence in asymptomatic frontline HCW was found to be 17.6%, with positivity being higher in the HCW group not facing patients directly compared to direct patient caregivers (P = 0.0034). Conclusion: Assay performance depends on assay design (total IgM & IgG antibodies versus IgG alone), choice of antigen, and time of sample testing from the onset of disease. In our study, Ortho Vitros total-Ab; IgG (Spike), and Roche Elecsys total-Ab (Nucleocapsid) assays were found to have optimal sensitivity. A seroprevalence study in the frontline HCWs at our institute showed that seroprevalence was higher (17.6%) in HCWs in comparison to the community.

scholarly journals Heat Pump Bridge Analysis Using the Modified Energy Transfer Diagram

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 137
Author(s):  
Florian Schlosser ◽  
Heinrich Wiebe ◽  
Timothy G. Walmsley ◽  
Martin J. Atkins ◽  
Michael R. W. Walmsley ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Heat Pump ◽  
Heat Recovery ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Combined Application ◽  
Recovery Potential ◽  
Composite Curve ◽  
And Performance ◽  
The Individual

Heat pumps are the key technology to decarbonise thermal processes by upgrading industrial surplus heat using renewable electricity. Existing insight-based integration methods refer to the idealised Grand Composite Curve requiring the full exploitation of heat recovery potential but leave the question of how to deal with technical or economic limitations unanswered. In this work, a novel Heat Pump Bridge Analysis (HPBA) is introduced for practically targeting technical and economic heat pump potential by applying Coefficient of Performance curves into the Modified Energy Transfer Diagram (METD). Removing cross-Pinch violations and operating heat exchangers at minimum approach temperatures by combined application of Bridge Analysis increases the heat recovery rate and reduce the temperature lift to be pumped at the same time. The insight-based METD allows the individual matching of heat surpluses and deficits of individual streams with the capabilities and performance of different market-available heat pump concepts. For an illustrative example, the presented modifications based on HPBA increase the economically viable share of the technical heat pump potential from 61% to 79%.

Analytical assessment of ortho clinical diagnostics high-sensitivity cardiac troponin I assay

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Peter A. Kavsak ◽  
Tara Edge ◽  
Chantele Roy ◽  
Paul Malinowski ◽  
Karen Bamford ◽  
...  
Keyword(s):  
Cardiac Troponin ◽  
Troponin I ◽  
Limit Of Detection ◽  
Clinical Performance ◽  
Characteristic Curve ◽  
Area Under The Curve ◽  
High Sensitivity ◽  
Cardiac Troponin I ◽  
Clinical Diagnostics ◽  
Ortho Clinical Diagnostics

AbstractObjectivesTo analytically evaluate Ortho Clinical Diagnostics VITROS high-sensitivity cardiac troponin I (hs-cTnI) assay in specific matrices with comparison to other hs-cTn assays.MethodsThe limit of detection (LoD), imprecision, interference and stability testing for both serum and lithium heparin (Li-Hep) plasma for the VITROS hs-cTnI assay was determined. We performed Passing-Bablok regression analyses between sample types for the VITROS hs-cTnI assay and compared them to the Abbott ARCHITECT, Beckman Access and the Siemens ADVIA Centaur hs-cTnI assays. We also performed Receiver-operating characteristic curve analyses with the area under the curve (AUC) determined in an emergency department (ED)-study population (n=131) for myocardial infarction (MI).ResultsThe VITROS hs-cTnI LoD was 0.73 ng/L (serum) and 1.4 ng/L (Li-Hep). Stability up to five freeze-thaws was observed for the Ortho hs-cTnI assay, with the analyte stability at room temperature in serum superior to Li-Hep with gross hemolysis also affecting Li-Hep plasma hs-cTnI results. Comparison of Li-Hep to serum concentrations (n=202), yielded proportionally lower concentrations in plasma with the VITROS hs-cTnI assay (slope=0.85; 95% confidence interval [CI]:0.83–0.88). In serum, the VITROS hs-cTnI concentrations were proportionally lower compared to other hs-cTnI assays, with similar slopes observed between assays in samples frozen <−70 °C for 17 years (ED-study) or in 2020. In the ED-study, the VITROS hs-cTnI assay had an AUC of 0.974 (95%CI:0.929–0.994) for MI, similar to the AUCs of other hs-cTn assays.ConclusionsLack of standardization of hs-cTnI assays across manufacturers is evident. The VITROS hs-cTnI assay yields lower concentrations compared to other hs-cTnI assays. Important differences exist between Li-Hep plasma and serum, with evidence of stability and excellent clinical performance comparable to other hs-cTn assays.

scholarly journals Eight Simple Guidelines for Improved Understanding of Transformations and Nonlinear Effects

2021 ◽  
pp. 109442812199190
Author(s):  
Mikko Rönkkö ◽  
Eero Aalto ◽  
Henni Tenhunen ◽  
Miguel I. Aguirre-Urreta
Keyword(s):  
Generalized Linear Model ◽  
Functional Form ◽  
Nonlinear Models ◽  
Nonlinear Effects ◽  
Recent Past ◽  
Organizational Research ◽  
Common Practices ◽  
Individual Variables ◽  
The Individual ◽  
The Relationship

Transforming variables before analysis or applying a transformation as a part of a generalized linear model are common practices in organizational research. Several methodological articles addressing the topic, either directly or indirectly, have been published in the recent past. In this article, we point out a few misconceptions about transformations and propose a set of eight simple guidelines for addressing them. Our main argument is that transformations should not be chosen based on the nature or distribution of the individual variables but based on the functional form of the relationship between two or more variables that is expected from theory or discovered empirically. Building on a systematic review of six leading management journals, we point to several ways the specification and interpretation of nonlinear models can be improved.

scholarly journals Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Andreas Peters ◽  
Zoltán S. Spakovszky
Keyword(s):  
Polar Angle ◽  
Secondary Flows ◽  
Tip Vortex ◽  
System Level ◽  
Analysis Tool ◽  
Acoustic Analogy ◽  
Wake Interaction ◽  
Open Rotor ◽  
And Performance ◽  
The Individual

Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3D unsteady, full-wheel CRP computational fluid dynamics computations and aeroacoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance, and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full-wheel unsteady 3D Reynolds-averaged Navier-Stokes (RANS) simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method was extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows, and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was redesigned for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the redesigned CRP demonstrated an average reduction of 7.25 dB in mean sound pressure level computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the redesigned CRP demonstrated a reduction of 9.2 dB in effective perceived noise (EPNdB) and 8.6 EPNdB at the Federal Aviation Regulations (FAR) 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements.

Time for caring? Elderly care employees’ occupational activities in the cross draft between their work priorities, ‘must-do’s’ and meaningfulness

2017 ◽  
Vol 20 (1-2) ◽  
pp. 8-16 ◽  
Author(s):  
Emma Nilsson ◽  
Kerstin Nilsson
Keyword(s):  
Focus Group ◽  
Care Coordination ◽  
Work Performance ◽  
Elderly Care ◽  
The Elderly ◽  
Focus Group Interviews ◽  
Care Giving ◽  
Group Interviews ◽  
And Performance ◽  
The Individual

An increasing number of older people in the population will bring new challenges for the society and care coordination. One of the most important questions in care coordination is the employees’ work performance. The overall aim of this study was to examine care employees’ experience of factors that rule how they allocate their time and tasks in the care work. The study was qualitative and consists of focus group interviews with 36 employees in elderly care in five Swedish municipalities. Much of the work that care employees perform is controlled by others in the municipality organised health care. The employees had a limited possibility to decide what should be given priority in their work. However, the employees who participated in the focus group interviews did not want to prioritise tasks and duties they felt were faulty or in direct conflict with their own convictions. When employees experienced that the assistance assessments were correct and helpful to the individual elderly patient this contributed to the employees’ priority and performance of the task. The formal and informal control systems caused the employees’ priority to be mainly quantitative and visible work tasks, rather than more qualitative tasks and care giving to the elderly. In the intention to organise good care coordination that fit each elderly patients’ need it is important that those who work closest to the patient to a greater extent are given the opportunity to make their voice heard in decisions of care planning and assistance assessments.

scholarly journals Sports Foods and Dietary Supplements for Optimal Function and Performance Enhancement in Track-and-Field Athletes

2019 ◽  
Vol 29 (2) ◽  
pp. 198-209 ◽  
Author(s):  
Peter Peeling ◽  
Linda M. Castell ◽  
Wim Derave ◽  
Olivier de Hon ◽  
Louise M. Burke
Keyword(s):  
Performance Enhancement ◽  
Evidence Base ◽  
Track And Field ◽  
Supplement Use ◽  
Optimal Function ◽  
Repeated Use ◽  
And Performance ◽  
The Individual ◽  
Health Function ◽  
Specific Scenario

Athletes are exposed to numerous nutritional products, attractively marketed with claims of optimizing health, function, and performance. However, there is limited evidence to support many of these claims, and the efficacy and safety of many products is questionable. The variety of nutritional aids considered for use by track-and-field athletes includes sports foods, performance supplements, and therapeutic nutritional aids. Support for sports foods and five evidence-based performance supplements (caffeine, creatine, nitrate/beetroot juice, β-alanine, and bicarbonate) varies according to the event, the specific scenario of use, and the individual athlete’s goals and responsiveness. Specific challenges include developing protocols to manage repeated use of performance supplements in multievent or heat-final competitions or the interaction between several products which are used concurrently. Potential disadvantages of supplement use include expense, false expectancy, and the risk of ingesting banned substances sometimes present as contaminants. However, a pragmatic approach to the decision-making process for supplement use is recommended. The authors conclude that it is pertinent for sports foods and nutritional supplements to be considered only where a strong evidence base supports their use as safe, legal, and effective and that such supplements are trialed thoroughly by the individual before committing to use in a competition setting.

Évaluation analytique multicentrique du bilan thyroïdien proposé par Ortho-Clinical Diagnostics sur le système Vitros ECi

1998 ◽  
Vol 13 (6) ◽  
pp. 377-387
Author(s):  
P Carayon ◽  
P Douet ◽  
A Gruson ◽  
J.P. Klein ◽  
P.J. Lejeune ◽  
...  
Keyword(s):  
Clinical Diagnostics ◽  
Ortho Clinical Diagnostics

scholarly journals Effects of Lean Tools in Achieving Lean Warehousing

2016 ◽  
Vol 54 (4) ◽  
pp. 517-534 ◽  
Author(s):  
Aleksandra Anđelković ◽  
Marija Radosavljević ◽  
Danijela Stošić
Keyword(s):  
Lean Principles ◽  
Before And After ◽  
Lean Tools ◽  
And Performance ◽  
The Individual ◽  
Warehouse Operations

Abstract The acceptance of lean philosophy in the company means not only respecting the lean principles in the manufacturing but in all the processes that are performed inside the company. All processes in the company that are a potential places for making losses and waste and thus require the application of lean principles. Among others, warehouse and warehouse operations, as a centre of costs and waste, must be supported through the implementation of lean philosophy in the company by respecting lean principles. The implementation of lean principles in the warehouse is a certain step of improvement warehouse process and performance, but also of the whole company. In that sense, the paper presents the analysis of the warehousing process and its performances before and after implementation of the lean tools in a selected Serbian company as a practical example. In addition, research shows which parts of warehousing need to be improved, in analysed company, as well as correlation between the individual parts of warehousing, according to employees' opinion from next sectors: purchasing, production and logistics.

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