A comparison between two different automated total 25-hydroxyvitamin D immunoassay methods using liquid chromatography-tandem mass spectrometry     

Fatma Emel Kocak  Bahadir Ozturk  Ozben Ozden Isiklar  Ozlem Genc  Ali Unlu  Irfan Altuntas 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2015,25(3):430-438

Introduction

Total 25-hydroxyvitamin D [25(OH)D] is the most reliable indicator of vitamin D status. In this study, we compared two automated immunoassay methods, the Abbott Architect 25-OH Vitamin D assay and the Roche Cobas Vitamin D total assay, with the liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Materials and methods

One hundred venous blood samples were randomly selected from routine vitamin D tests. Two of the serum aliquots were analyzed at the Abbott Architect i2000 and the Roche Cobas 6000’s module e601 in our laboratory within the same day. The other serum aliquots were analyzed at the LC-MS/MS in different laboratory. Passing-Bablok regression analysis and Bland-Altman plot were used to compare methods. Inter-rater agreement was analyzed using kappa (κ) analysis.

Results

The Roche assay showed acceptable agreement with the LC-MS/MS based on Passing-Bablok analysis (intercept: -5.23 nmol/L, 95% CI: -8.73 to 0.19; slope: 0.97, 95% CI: 0.77 to 1.15). The Abbott assay showed proportional (slope: 0.77, 95% CI: 0.67 to 0.85) and constant differences (intercept: 17.08 nmol/L; 95% CI: 12.98 to 21.39). A mean bias of 15.1% was observed for the Abbott and a mean bias of -14.1% was observed for the Roche based on the Bland-Altman plots. We found strong to nearly perfect agreement in vitamin D status between the immunoassays and LC-MS/MS. (κ: 0.83 for Abbott, κ: 0.93 for Roche) using kappa analysis.

Conclusion

Both immunoassays demonstrated acceptable performance, but the Roche Cobas assay demonstrated better performance than the Abbott Architect in the studied samples.Key words: 25-Hydroxyvitamin D, chromatography, immunoassay, methods, tandem mass spectrometry  相似文献   

Collaborative project-based learning: an integrative science and technological education project     

Derya Baser  M. Yasar Ozden  Hasan Karaarslan 《Research in Science & Technological Education》2017,35(2):131-148

Background: Blending collaborative learning and project-based learning (PBL) based on Wolff (2003) design categories, students interacted in a learning environment where they developed their technology integration practices as well as their technological and collaborative skills.

Purpose: The study aims to understand how seventh grade students perceive a collaborative web-based science project in light of Wolff’s design categories. The goal of the project is to develop their technological and collaborative skills, to educate them about technology integration practices, and to provide an optimum collaborative, PBL experience.

Sample: Seventh grade students aged 12–14 (n = 15) were selected from a rural K–12 school in Turkey through purposeful sampling.

Design and methods: The current study applied proactive action research since it focused on utilizing a new way to enhance students’ technological and collaborative skills and to demonstrate technology integration into science coursework. Data were collected qualitatively through interviews, observation forms, forum archives, and website evaluation rubrics.

Results: The results found virtual spaces such as online tutorials, forums, and collaborative and communicative tools to be beneficial for collaborative PBL. The study supported Wolff’s design features for a collaborative PBL environment, applying features appropriate for a rural K–12 school setting and creating a digitally-enriched environment. As the forum could not be used as effectively as expected because of school limitations, more flexible spaces independent of time and space were needed.

Conclusions: This study’s interdisciplinary, collaborative PBL was efficient in enhancing students’ advanced technological and collaborative skills, as well as exposing them to practices for integrating technology into science. The study applied design features for a collaborative PBL environment with certain revisions.  相似文献   

A case study of beginning science teachers’ subject matter (SMK) and pedagogical content knowledge (PCK) of teaching chemical reaction in Turkey     

Muhammet Usak  Mustafa Ozden  Ingo Eilks 《欧洲师范教育杂志》2011,34(4):407-429

This paper describes a case study focusing on the subject matter knowledge, pedagogical content knowledge, and beliefs about science teaching of student teachers in Turkey at the start of their university education. The topic of interest was that of teaching chemical reactions in secondary chemistry education. A written test was developed which used the research literature on potential student misconceptions with regard to different aspects of chemical reactions. Thirty beginning science student teachers were tested, with an additional eight interviews from the student teachers in the same sample. The interviews focused on student teachers’ views about how to best teach chemical reactions in lower secondary chemistry classes. The results revealed deficits in the subject matter knowledge of the student teachers. It also became obvious that the teachers in this sample held very traditional and teacher-centred beliefs when it came to chemistry teaching at the secondary level. Their teaching attitudes were geared mainly towards the acquisition of facts by pupils, and often ignored the development of process-oriented skills. Implications for science teacher education are discussed.  相似文献   

Comparison of blood ethanol stabilities in different storage periods     

Fatma Emel Kocak  Ozben Ozden Isiklar  Havva Kocak  Ayfer Meral 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2015,25(1):57-63

Introduction

Measurements of blood ethanol concentrations must be accurate and reliable. The most important factors affecting blood ethanol stability are temperature and storage time. In this study, we aimed to compare ethanol stability in plasma samples at -20 °C for the different storage periods.

Materials and methods

Blood samples were collected from intoxicated drivers (N = 80) and initial plasma ethanol concentrations were measured immediately. Plasma samples were then stored at -20 °C and re-assessed after 2, 3, 4, or 5 months of storage. Differences between the initial and stored ethanol concentrations in each group (N = 20) were analyzed using Wilcoxon matched-pairs test. The deviation from the initial concentration was calculated and compared with Clinical Laboratory Improvement Amendments (CLIA’88) Proficiency Testing Limits. Relationships between the initial concentrations and deviations from initial concentrations were analyzed by Spearman’s correlation analysis. For all statistical tests, differences with P values of less than 0.05 were considered statistically significant.

Results

Statistically significant differences were observed between the initial and poststorage ethanol concentrations in the overall sample group (P < 0.001). However, for the individual storage duration groups, analytically significant decreases were observed only for samples stored for 5 months, deviations from the initial concentrations exceeded the allowable total error (TEa). Ethanol decreases in the other groups did not exceed the TEa.

Conclusion

According to our results, plasma ethanol samples can be kept at -20 °C for up to 3-4 months until re-analysis. However, each laboratory should also establish its own work-flow rules and criterion for reliable ethanol measurement in forensic cases.Key words: preanalytical phase, ethanol, stability, storage temperature  相似文献