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A microfluidic device that is able to perform dielectric spectroscopy is developed. The device consists of a measurement chamber that is 250 μm thick and 750 μm in radius. Around 1000 cells fit inside the chamber assuming average quantities for cell radius and volume fraction. This number is about 1000 folds lower than the capacity of conventional fixtures. A T-cell leukemia cell line Jurkat is tested using the microfluidic device. Measurements of deionized water and salt solutions are utilized to determine parasitic effects and geometric capacitance of the device. Physical models, including Maxwell-Wagner mixture and double shell models, are used to derive quantities for sub-cellular units. Clausius-Mossotti factor of Jurkat cells is extracted from the impedance spectrum. Effects of cellular heterogeneity are discussed and parameterized. Jurkat cells are also tested with a time domain reflectometry system for verification of the microfluidic device. Results indicate good agreement of values obtained with both techniques. The device can be used as a unique cell diagnostic tool to yield information on sub-cellular units. 相似文献
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Küme T Sişman AR Solak A Tuğlu B Cinkooğlu B Coker C 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2012,22(2):189-201
Introductıon:
We evaluated the effect of different syringe volume, needle size and sample volume on blood gas analysis in syringes washed with heparin.Materials and methods:
In this multi-step experimental study, percent dilution ratios (PDRs) and final heparin concentrations (FHCs) were calculated by gravimetric method for determining the effect of syringe volume (1, 2, 5 and 10 mL), needle size (20, 21, 22, 25 and 26 G) and sample volume (0.5, 1, 2, 5 and 10 mL). The effect of different PDRs and FHCs on blood gas and electrolyte parameters were determined. The erroneous results from nonstandardized sampling were evaluated according to RiliBAK’s TEa.Results:
The increase of PDRs and FHCs was associated with the decrease of syringe volume, the increase of needle size and the decrease of sample volume: from 2.0% and 100 IU/mL in 10 mL-syringe to 7.0% and 351 IU/mL in 1 mL-syringe; from 4.9% and 245 IU/mL in 26G to 7.6% and 380 IU/mL in 20 G with combined 1 mL syringe; from 2.0% and 100 IU/mL in full-filled sample to 34% and 1675 IU/mL in 0.5 mL suctioned sample into 10 mL-syringe. There was no statistical difference in pH; but the percent decreasing in pCO2, K+, iCa2+, iMg2+; the percent increasing in pO2 and Na+ were statistical significance compared to samples full-filled in syringes. The all changes in pH and pO2 were acceptable; but the changes in pCO2, Na+, K+ and iCa2+ were unacceptable according to TEa limits except fullfilled-syringes.Conclusions:
The changes in PDRs and FHCs due nonstandardized sampling in syringe washed with liquid heparin give rise to erroneous test results for pCO2 and electrolytes. 相似文献14.
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The quality of teacher education, in general, is affected from a number of variables such as physical environment of the institutions,
instructor quality, the curriculum implemented, administrative support, and others. As the input of the system, the perspectives
of the students on those variables also influence the direction and the quality of the education taking place in the colleges
of education. Regarding this, the purpose of the present study is to identify and compare the perspectives of fourth-year
English Language Teaching students on the physical environment, human resources, and the program of three ELT departments
at three different state universities. As part of the survey research design, the questionnaire was administered to totally
278 prospective English Teachers from the ELT departments at state universities in Ankara. The results of the study, unlike
the past research on the issue, presented that the prospective English teachers had positive views on the instructors and
program generally; however, they stated problems on the physical environment of their departments. Moreover, there were significant
differences in students’ views on the physical environment, resources, and its sub-dimensions. The students from the institution,
which was renovated before the study, had more positive views on their department than the others. The results suggested it
might be useful to reevaluate and reconsider the current conditions of the English language teacher education in relation
to the departments’ human resources, program and especially the physical environment. 相似文献
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There is debate about whether the leadership style of the teacher or the learning style of the student affects academic achievement more. A large sample (n = 746) of eighth‐grade students in Istanbul, Turkey, participated in a study where the leadership style of the teacher was assessed in terms of people orientation and task orientation. The learning styles examined were: group, individual, visual, auditory, tactile, and kinesthetic. Multiple discriminant analysis indicated that teacher leadership style was the main factor affecting academic performance. No significant relationship was found between learning style and academic achievement. 相似文献
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Ahmet Baytak Susan M. Land 《Educational technology research and development : ETR & D》2011,59(6):765-782
This study employed a case study design (Yin, Case study research, design and methods, 2009) to investigate the processes used by 5th graders to design and develop computer games within the context of their environmental
science unit, using the theoretical framework of constructionism. Ten fifth graders designed computer games using Scratch software. The results showed students were able to design functional games, following a learning-by-design process of planning,
designing, testing, and sharing. Observations revealed that game design led to opportunities for informal knowledge building
and sharing among students. This, in turn, encouraged students to test and improve their designs. The findings support the
conclusion that elementary students can develop programming concepts and create computer games when using graphical programming
software developed for their level of experience. Insights into the iterative process of learning-by-game design are presented. 相似文献
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Learning Environments Research - In this study, we examined a mathematics teacher’s communicative acts on an instant messaging tool, WhatsApp, and its role in creating a sustained learning... 相似文献
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Ahmet Basal 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(1):342-356
Collocations are word combinations essential for achieving fluency in a given language. Considerable emphasis should therefore be placed on teaching collocations as a part of vocabulary instruction in language teaching. However, there is no current consensus on how best to teach collocations, and few studies have addressed the issue. This quasi-experimental study investigated the effectiveness of online tools for learning English adjective-noun collocations compared to learning collocations via traditional activities. A quasi-experimental design with a pretest and immediate and delayed posttests was applied to 53 participants (n = 25 for the control group; n = 28 for the experimental group). The test results reveal that participants in the experimental group who learned collocations with online tools performed significantly better on both immediate and delayed posttests, demonstrating the effectiveness of these tools on learning adjective-noun collocations. 相似文献
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The purpose of this nationwide survey was to assess young Turkish pupils’ environmental literacy (EL) level by considering six EL components. The sample of the study comprised of 2,412 fifth graders selected from 78 elementary schools (26 private and 52 public) in 26 provinces of Turkey. Data were obtained through the use of an elementary school environmental literacy instrument (ESELI) including five parts and total of 75 items. The results revealed that the composite EL score of the students was found to be 149.66 (SD = 26.19), suggesting a moderate level of EL among 61% percent of the students (n = 1,545). On the other hand, more than a quarter of the participants (27.3%, n = 659) held high level EL, whereas only 22 students (0.9%) showed low level EL. The implications of the results to policy, practice, and further research were discussed at the end of the study. 相似文献