scholarly journals Commutability Assessment of Potential Reference Materials Using a Multicenter Split-Patient-Sample Between-Field-Methods (Twin-Study) Design: Study within the Framework of the Dutch Project “Calibration 2000”

2002 ◽  
Vol 48 (9) ◽  
pp. 1520-1525 ◽  
Author(s):  
Henk Baadenhuijsen ◽  
Herman Steigstra ◽  
Christa Cobbaert ◽  
Aldy Kuypers ◽  
Cas Weykamp ◽  
...  
Keyword(s):  
Study Design ◽  
Reference Materials ◽  
Twin Study ◽  
State Of The Art ◽  
Regression Line ◽  
Hdl Cholesterol ◽  
Field Methods ◽  
Patient Sample ◽  
Serum Pool ◽  
Alternative Approach

Abstract Background: The Dutch project “Calibration 2000” aims at harmonization of laboratory results via calibration by development of commutable, matrix-based, secondary reference materials. An alternative approach to the NCCLS EP14 protocol for studying commutability of reference materials is presented, the “twin-study design”, which in essence is a multicenter, split-patient-sample, between-field-methods protocol. Methods: The study consisted of the simultaneous analysis of fresh patient sera and potential reference materials (PRMs) for HDL-cholesterol (HDL-C) by 86 laboratories forming 43 laboratory couples. Six subgroups of method combinations were formed. The patient sera were selected and interchanged by each laboratory couple. The PRMs consisted of three types: C37, prepared according to the NCCLS C37 protocol; Fro, frozen selectively pooled human serum; and Lyo, which was the same serum pool as Fro but lyophilized in the presence of sucrose. All PRMs were provided in three HDL-C concentrations. The regression line residuals for the PRMs were normalized by expressing them as multiples of the state-of-the-art within laboratory SD (SDSA). In addition, the extra contribution of each PRM to the total measurement uncertainty, CVNetto, was calculated. Results: Averaged over the three PRM concentrations, 1.6% of the C37 residuals were outside the 3 SDSA limit. For the Fro and Lyo PRMs, these values were 2.4% and 11.1%. CVNetto values for C37, Fro, and Lyo were 2.9%, 4.3%, and 5.3%, respectively. Conclusions: The present twin-study design, as a practical alternative to the NCCLS EP14 protocol, is a viable way of studying commutability characteristics of PRMs. The study suggests that the C37 PRMs are the best candidates for a future reference material.

Multicenter evaluation of the commutability of a potential reference material for harmonization of enzyme activities

2004 ◽  
Vol 42 (12) ◽  
Author(s):  
Volkher Scharnhorst ◽  
Joke Apperloo ◽  
Henk Baadenhuijsen ◽  
Huib L. Vader
Keyword(s):  
Reference Material ◽  
Reference Materials ◽  
Enzyme Activities ◽  
Regression Line ◽  
Reference Intervals ◽  
Correction Factors ◽  
Serum Samples ◽  
Field Methods ◽  
Common Reference ◽  
Fold Reduction

AbstractStandardization of laboratory results allows for the use of common reference intervals and can be achieved via calibration of field methods with secondary reference materials. These harmonization materials should be commutable, i.e., they produce identical numerical results independent of assay principle or platform. This study assessed the commutability of a cryolyoprotectant-containing harmonization material, obtained from the Dutch Foundation for Quality Assessment in Clinical Laboratories, that is intended to harmonize measurements of enzyme activities within the Dutch project “Calibration 2000”. The catalytic concentrations of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, γ-glutamyltransferase and creatine kinase were analyzed in pooled patient sera and in the reference material in 14 laboratories. On liquid chemistry analyzers the harmonization material behaves like patient material. The enzyme activities measured in it fall on the regression lines calculated from activities measured in serum samples. For dry chemistry analyzers the activities of all enzymes measured in the harmonizator differ from the serum-based regression line. We show that this is due to the sucrose-containing cryolyoprotectant in the harmonization material. For each enzyme, correction factors were calculated that compensated for the bias and proved to be constant between reagent lots. Depending on the enzyme activity measured, application of these factors leads to 2- to 10-fold reduction of between-laboratory percentage coefficient of variation. Thus, additives to (potential) reference materials may alter their matrix in a way that interferes with analysis on certain test systems. The bias caused may be quantifiable and correctable. Establishment of correction factors leads to analytical uncertainties and costs. Therefore, matrix-based materials without additives should be selected as reference materials.

scholarly journals Minimum convex hull mass estimations of complete mounted skeletons

2012 ◽  
Vol 8 (5) ◽  
pp. 842-845 ◽  
Author(s):  
W. I. Sellers ◽  
J. Hepworth-Bell ◽  
P. L. Falkingham ◽  
K. T. Bates ◽  
C. A. Brassey ◽  
...  
Keyword(s):  
Convex Hull ◽  
Body Mass ◽  
Laser Scanning ◽  
Regression Line ◽  
The Body ◽  
Alternative Approach ◽  
Subjective Input ◽  
Skeletal Reconstruction ◽  
Volumetric Methods ◽  
User Intervention

Body mass is a critical parameter used to constrain biomechanical and physiological traits of organisms. Volumetric methods are becoming more common as techniques for estimating the body masses of fossil vertebrates. However, they are often accused of excessive subjective input when estimating the thickness of missing soft tissue. Here, we demonstrate an alternative approach where a minimum convex hull is derived mathematically from the point cloud generated by laser-scanning mounted skeletons. This has the advantage of requiring minimal user intervention and is thus more objective and far quicker. We test this method on 14 relatively large-bodied mammalian skeletons and demonstrate that it consistently underestimates body mass by 21 per cent with minimal scatter around the regression line. We therefore suggest that it is a robust method of estimating body mass where a mounted skeletal reconstruction is available and demonstrate its usage to predict the body mass of one of the largest, relatively complete sauropod dinosaurs: Giraffatitan brancai (previously Brachiosaurus ) as 23200 kg.

Genetic Component of Noise Sensitivity

2005 ◽  
Vol 8 (3) ◽  
pp. 245-249 ◽  
Author(s):  
Marja Heinonen-Guzejev ◽  
Heikki S. Vuorinen ◽  
Helena Mussalo-Rauhamaa ◽  
Kauko Heikkilä ◽  
Markku Koskenvuo ◽  
...  
Keyword(s):  
Study Design ◽  
Twin Study ◽  
Genetic Model ◽  
Hearing Impaired ◽  
Genetic Component ◽  
Noise Sensitivity ◽  
Quantitative Genetic ◽  
Genetic Modeling ◽  
Health Related ◽  
Age Range

AbstractWe investigated the genetic component of noise sensitivity using a twin-study design. The study sample consisted of 573 same-sexed twin pairs from the Finnish Twin Cohort. The 131 monozygotic (MZ) and 442 dizygotic (DZ) twin pairs with an age range of 31 to 88 years replied to a questionnaire on noise and health-related items in 1988. The noise sensitivity of respondents was defined as high, quite high, quite low or low. MZ pairs were more similar with regards noise sensitivity than DZ pairs, and quantitative genetic modeling indicated significant familiality. The best z-fitting genetic model provided an estimate of heritability of 36% (95% CI = .20–.50) and when hearing impaired subjects were excluded this rose to 40% (95% CI = .24–.54). In conclusion, noise sensitivity does aggregate in families and probably has a genetic component.

scholarly journals Detecting Emotions in English and Arabic Tweets

Information ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 98 ◽  
Author(s):  
Tariq Ahmad ◽  
Allan Ramsay ◽  
Hanady Ahmed
Keyword(s):  
Machine Learning ◽  
Neural Networks ◽  
Deep Neural Networks ◽  
State Of The Art ◽  
Learning Algorithms ◽  
General Purpose ◽  
Machine Learning Algorithms ◽  
Current State ◽  
Optimal Thresholds ◽  
Alternative Approach

Assigning sentiment labels to documents is, at first sight, a standard multi-label classification task. Many approaches have been used for this task, but the current state-of-the-art solutions use deep neural networks (DNNs). As such, it seems likely that standard machine learning algorithms, such as these, will provide an effective approach. We describe an alternative approach, involving the use of probabilities to construct a weighted lexicon of sentiment terms, then modifying the lexicon and calculating optimal thresholds for each class. We show that this approach outperforms the use of DNNs and other standard algorithms. We believe that DNNs are not a universal panacea and that paying attention to the nature of the data that you are trying to learn from can be more important than trying out ever more powerful general purpose machine learning algorithms.

scholarly journals Reporting Device Performance of Emerging Photovoltaic Materials (Version 1)

2021 ◽  
Author(s):  
Osbel Almora ◽  
Derya Baran ◽  
Guillermo C Bazan ◽  
Carlos I Cabrera ◽  
Kylie R Catchpole ◽  
...  
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Perovskite Solar Cells ◽  
Bandgap Energy ◽  
Energy Yield ◽  
Research Subjects ◽  
Dye Sensitized ◽  
Alternative Approach ◽  
The Stability ◽  
Reported Data

Emerging photovoltaics (PVs), focuses on a variety of applications complementing large scale electricity generation. For instance, organic, dye-sensitized and some perovskite solar cells are considered in building integration, greenhouses, wearable and indoors, thereby motivating research on flexible, transparent, semitransparent, and multi-junction PVs. Nevertheless, it can be very time consuming to find or develop an up-to-date overview over the state-of-the-art performance for these systems and applications. Two important resources for record research cells efficiencies are the National Renewable Energy Laboratory chart and the efficiency tables compiled biannually by Martin Green and colleagues. Both publications provide an effective coverage over the established technologies, bridging research and industry. An alternative approach is proposed here summarizing the best reports in the diverse research subjects for emerging PVs. Best performance parameters are provided as a function of the photovoltaic bandgap energy for each technology and application, and are put into perspective using, e.g., the Shockley-Queisser limit. In all cases, the reported data correspond to published and/or properly described certified results, with enough details provided for prospective data reproduction. Additionally, the stability test energy yield (STEY) is included as an analysis parameter among state-of-the-art emerging PVs.

International Federation of Clinical Chemistry Standardization Project for Measurements of Apolipoproteins A-I and B. II. Evaluation and Selection of Candidate Reference Materials

1992 ◽  
Vol 38 (5) ◽  
pp. 658-662 ◽  
Author(s):  
J J Albers ◽  
S M Marcovina ◽  
H Kennedy
Keyword(s):  
Reference Materials ◽  
Clinical Chemistry ◽  
Collaborative Study ◽  
Second Phase ◽  
Serum Samples ◽  
Apo B ◽  
Common Reference ◽  
Test Systems ◽  
Serum Pool ◽  
Fresh Frozen

Abstract The first phase of an international collaborative study for standardization of test systems for measuring apolipoprotein (apo) A-I and apo B demonstrated that uniformity of apo A-I and apo B measurements can be achieved if suitable common reference materials are used to calibrate the different systems. The objective of the second phase was to evaluate the linearity and parallelism or proportionality of the candidate reference materials selected in phase one and to determine whether any of them could be proposed as international reference materials. We evaluated the proposed reference materials with 37 test systems for apo A-I and 38 for apo B, involving 23 manufacturers and five research laboratories. Two lyophilized preparations were proposed for apo A-I, SP1 from Behringwerke AG and SP2 from Daiichi Pure Chemicals Co., and two liquid preparations were proposed for apo B, SP3 from Behringwerke AG and SP4 from Reagents Applications. The linearity of the candidate reference materials was compared with the linearity of a frozen serum pool or interim serum reference material distributed to all the participants and with that of a fresh serum pool prepared by each participant. SP1 and SP3 exhibited linearity and parallelism similar to that of the fresh frozen serum pool and had among-laboratory CVs less than or similar to those obtained on normolipidemic serum samples (approximately 6% for apo A-I and approximately 7% for apo B).

scholarly journals Twin Research in the Post-Genomic Era: Dissecting the Pathophysiological Effects of Adversity and the Social Environment

2020 ◽  
Vol 21 (9) ◽  
pp. 3142 ◽  
Author(s):  
Jonathan D. Turner ◽  
Conchita D’Ambrosio ◽  
Claus Vögele ◽  
Martin Diewald
Keyword(s):  
Social Environment ◽  
Study Design ◽  
Twin Study ◽  
Controlled Trial ◽  
Twin Studies ◽  
Twin Design ◽  
The Social ◽  
The Individual ◽  
Randomised Controlled

The role of twins in research is evolving as we move further into the post-genomic era. With the re-definition of what a gene is, it is becoming clear that biological family members who share a specific genetic variant may well not have a similar risk for future disease. This has somewhat invalidated the prior rationale for twin studies. Case co-twin study designs, however, are slowly emerging as the ideal tool to identify both environmentally induced epigenetic marks and epigenetic disease-associated processes. Here, we propose that twin lives are not as identical as commonly assumed and that the case co-twin study design can be used to investigate the effects of the adult social environment. We present the elements in the (social) environment that are likely to affect the epigenome and measures in which twins may diverge. Using data from the German TwinLife registry, we confirm divergence in both the events that occur and the salience for the individual start as early as age 11. Case co-twin studies allow for the exploitation of these divergences, permitting the investigation of the role of not only the adult social environment, but also the salience of an event or environment for the individual, in determining lifelong health trajectories. In cases like social adversity where it is clearly not possible to perform a randomised-controlled trial, we propose that the case co-twin study design is the most rigorous manner with which to investigate epigenetic mechanisms encoding environmental exposure. The role of the case co-twin design will continue to evolve, as we argue that it will permit causal inference from observational data.

scholarly journals A System for Extracting Study Design Parameters from Nutritional Genomics Abstracts

2013 ◽  
Vol 10 (2) ◽  
pp. 82-93 ◽  
Author(s):  
Cassidy Kelly ◽  
Hui Yang
Keyword(s):  
Language Processing ◽  
Study Design ◽  
State Of The Art ◽  
Design Parameters ◽  
Regular Expressions ◽  
Journal Articles ◽  
Current State ◽  
Novel Approach ◽  
Algorithmic Framework ◽  
Nutritional Genomics

Summary The extraction of study design parameters from biomedical journal articles is an important problem in natural language processing (NLP). Such parameters define the characteristics of a study, such as the duration, the number of subjects, and their profile. Here we present a system for extracting study design parameters from sentences in article abstracts. This system will be used as a component of a larger system for creating nutrigenomics networks from articles in the nutritional genomics domain. The algorithms presented consist of manually designed rules expressed either as regular expressions or in terms of sentence parse structure. A number of filters and NLP tools are also utilized within a pipelined algorithmic framework. Using this novel approach, our system performs extraction at a finer level of granularity than comparable systems, while generating results that surpass the current state of the art.

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