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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2.
Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules. 相似文献
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Aysen Bakioglu Ozlem Kurnaz 《美中教育评论》2009,6(3):1-12,27
The purpose of this study is to examine the problem of research quality in social sciences at higher education. Quality of research produced at higher education started to be questioned more often as research became the major factor determining academics＇ promotion and fund allocation to universities. In the study, we aimed to reveal how academics perceive research quality and what they identify as the main problems that make it difficult to achieve quality in research. Data were collected through interviews with 25 academics from 7 disciplines （educational sciences, sociology, communicational sciences, law, history, management and political science） in 7 universities. Six of the academics interviewed were professors, 7 were associate professors, 10 were assistant professors and 2 were doctors. Interviews were carried out in 2006-2007 and 2007-2008 academic years, and each lasted about one hour on average. Data collected were analyzed through content analysis. Study findings revealed that academics referred most often to methodological issues as the most important quality criterion of research, followed by issues of theoretical background and originality. Academics definitions of sub-criteria related to these were tackled in more detail in the study. As the most important hindrances that make it difficult to achieve quality in research academics mentioned lack of a long-established research culture, problems of research resources and the pressure caused by academic promotion criteria. Some recommendations related to the problems were made to develop research quality in the light of the study findings. 相似文献
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Niyazi Samet Yilmaz Bayram Sen Ozlem Gulbahar 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2021,31(2)
Errors in laboratory medicine occur in the preanalytical, analytical, and postanalytical phases. The errors are mostly detected in the preanalytical period. However, analytical errors are still an important source of error, despite their frequency is reduced significantly in years thanks to developments in laboratories. In this case, an analytical error was noticed during the verification of a patient’s results. The direct bilirubin of a 66-year-old male patient admitted to the emergency department was higher than the total bilirubin. The patient’s symptoms were fatigue and dyspnoea. Albumin and haemoglobin (Hb) concentrations of the patient were significantly low. After considering the patient’s demographics and laboratory results, the laboratory specialist suspected a paraproteinemia interference. Total protein was performed as a reflective test. The albumin/globulin ratio was reversed. Thereafter, serum protein electrophoresis (SPEP) and immunofixation electrophoresis (IFE) were performed as another reflective tests, respectively. SPEP and IFE results were in favour of monoclonal gammopathy. The patient was directed to a haematologist, underwent a bone marrow biopsy, and the result was reported as Waldenstrom’s macroglobulinemia with plasma cell differentiation expressing IgM-Kappa. The patient went on a chemotherapy protocol, and his condition has been improved in subsequent months. Detection of analytical errors is of great importance, like in our case, and may be used as a tool to identify patients who have not yet been diagnosed. The laboratory specialist must dominate the entire process of each test in the laboratory, be aware of the limitations of tests, and turn these disadvantages into advantages when necessary. 相似文献
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Recent instructional reforms in science education aim to change the way students engage in learning in the discipline, as they describe that students are to engage with disciplinary core ideas, crosscutting concepts, and the practices of science to make sense of phenomena (NRC, 2012). For such sensemaking to become a reality, there is a need to understand the ways in which students' thinking can be maintained throughout the trajectory of science lessons. Past research in this area tends to foreground either the curriculum or teachers' practices. We propose a more comprehensive view of science instruction, one that requires attention to teachers' practice, the instructional task, and students' engagement. In this study, by examining the implementation of the same lesson across three different classrooms, our analysis of classroom videos and artifacts of students' work revealed how the interaction of teachers' practices, students' intellectual engagement, and a cognitively demanding task together support rigorous instruction. Our analyses shed light on their interaction that shapes opportunities for students' thinking and sensemaking throughout the trajectory of a science lesson. The findings provide implications for ways to promote rigorous opportunities for students' learning in science classrooms. 相似文献
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This study examines impact of the educational use of Facebook group on the high school students’ proper usage of language. The study included thirty students who attend 11th grade in a high school in Trabzon, Turkey. Firstly, preliminary data about Facebook usage of students were obtained to understand the factors that motivate students to use Facebook and whether they use them for the educational purpose or not. Then, a Facebook group was created, in which a literature teacher was assigned as the guide of the group. This study lasted twelve weeks. The students’ assignments such as compositions, poems, and vignettes, discussions, the teacher’s views and observation, data from the interviews with participants were analyzed in this study. Results from this study indicated that that Facebook group was effective on issues such as development of writing abilities of students, communication and cooperation between teacher and students, and cooperation and communication among students. The original idea for this research was to determine that proper usage of language can be improved in social context if Facebook group is created as a flexible online community with interactive and reflective activities, effective tool of sharing and communication. This study demonstrates how Facebook can successfully be used in educational environment appropriately. 相似文献
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Rabia M. Yilmaz Ozlem Baydas 《Educational technology research and development : ETR & D》2017,65(6):1547-1567
The aim of the study is to examine undergraduate students’ awareness of metacognition, the metacognitive strategies they use in their learning and their learning performance in pre-class asynchronous activity in a flipped classroom. The sample consisted of 47 undergraduate students. Eleven students were not included in this study since they did not participate in all quizzes and most of the metacognitive strategy activities. Metacognitive Awareness Inventory and Metacognitive Strategies Evaluation Activities were used as data collection tools. The results showed that Computer Education and Instructional Technology students’ metacognitive awareness was at a high level and their metacognitive strategy levels and learning performances differed weekly. Post hoc results indicated no difference between metacognitive strategy and learning performance in the first three weeks. However, the results of the first 3 weeks differed from those of the 4th and 5th weeks. In addition, our regression analysis result indicated that using metacognitive strategies predicted 80% of students’ learning performance. This rate shows the importance of using metacognitive strategies for the learning process in pre-class asynchronous activity in the flipped classroom. 相似文献
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Formulation of the DETECT Population Parameter and Evaluation of DETECT Estimator Bias 总被引：1，自引：0，他引：1
The development of the DETECT procedure marked an important advancement in nonparametric dimensionality analysis. DETECT is the first nonparametric technique to estimate the number of dimensions in a data set, estimate an effect size for multidimensionality, and identify which dimension is predominantly measured by each item. The efficacy of DETECT critically depends on accurate, minimally biased estimation of the expected conditional covariances of all the item pairs. However, the amount of bias in the DETECT estimator has been studied only in a few simulated unidimensional data sets. This is because the value of the DETECT population parameter is known to be zero for this case and has been unknown for cases when multidimensionality is present. In this article, integral formulas for the DETECT population parameter are derived for the most commonly used parametric multidimensional item response theory model, the Reckase and McKinley model. These formulas are then used to evaluate the bias in DETECT by positing a multidimensional model, simulating data from the model using a very large sample size (to eliminate random error), calculating the large-sample DETECT statistic, and finally calculating the DETECT population parameter to compare with the large-sample statistic. A wide variety of two- and three-dimensional models, including both simple structure and approximate simple structure, were investigated. The results indicated that DETECT does exhibit statistical bias in the large-sample estimation of the item-pair conditional covariances; but, for the simulated tests that had 20 or more items, the bias was small enough to result in the large-sample DETECT almost always correctly partitioning the items and the DETECT effect size estimator exhibiting negligible bias. 相似文献