A disposable card incorporating specific DNA probes targeting the 16 S rRNA gene of Streptococcus suis was developed for magnetically labeled target DNA detection. A singlestranded target DNA was hybridized with the DNA probe on the SPA/APTES/PDMS/Si asprepared card, which was subsequently magnetically labeled with superparamagnetic beads for detection using an anisotropic magnetoresistive (AMR) sensor. An almost linear response between the output signal of the AMR sensor and amount of single-stranded target DNA varied from 4.5 to 18 pmol was identified. From the sensor output signal response towards the mass of magnetic beads which were directly immobilized on the disposable card surface, the limit of detection was estimated about 312 ng ferrites, which corresponds to 3.8 μemu. In comparison with DNA detection by conventional biosensor based on magnetic bead labeling, disposable cards are featured with higher efficiency and performances, ease of use and less running cost with respects to consumables for biosensor in biomedical analysis systems operating with immobilized bioreceptor.
Magnetic field sensors based on the planar Hall effect using single layer Ni 80 Fe 20 thin films have been designed, fabricated and characterized. By optimizing the sensor's dimension, such as the thickness and the length to width ratio, experimental results have shown that the sensor's sensitivity could be increased up to three times thanks to the enhancement of the shape magnetic anisotropy. The highest sensitivity of 100 μV Oe −1 corresponding to the relative resistance change up to 20 mΩ/Oe was achieved at a supplied DC current of 5 mA for the cross-shaped geometry of the sensor with 5 nm in the thickness and a length/width ratio of 10. Simple structure, low fabrication cost, and low power consumption make this sensor very promising for low field magnetic field sensing such as geomagnetic field detections.
In this paper, we propose a new STEM topic in the automation field for upper-secondary school students, which is the topic "Traffic signal lights". This STEM education is designed to be relevant to the current general education curriculum in subjects as Physics, Technology, and Informatics. Based on the 6E learning model, the teaching process is built for this topic, in which two factors of technical design and practice (programming and assembly of circuits) are emphasized in STEM-oriented teaching for upper-secondary school students.
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