Hironao Okada

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The Asian H5N1 highly pathogenic avian influenza (HPAI) viruses have been increasing in pathogenicity in diverse avian species since 1996 and are now widespread in Asian, European, and African countries. To better understand the basis of the increased pathogenicity of recent Asian H5N1 HPAI viruses in chickens, we compared the fevers and mean death times(More)
We evaluate an availability of a method for detecting chickens infected with the highly pathogenic avian influenza (HPAI) viruses at the early stage in poultry farms using a wireless sensor node with temperature sensor and accelerometer. Chicken infection experiments by using the developed prototype wireless sensor node showed that weakness and fever of the(More)
The molecular basis of pathogenicity of H5N1 highly pathogenic avian influenza (HPAI) viruses in chickens remains largely unknown. H5N1 A/chicken/Yamaguchi/7/2004 virus (CkYM7) replicates rapidly in macrophages and vascular endothelial cells in chickens, causing sudden death without fever or gross lesions, while H5N1 A/duck/Yokohama/aq10/2003 virus (DkYK10)(More)
We developed a prototype wearable wireless node with a thermister and an accelerometer for a chicken, and evaluated the availability of a method for detecting chickens infected with the highly pathogenic avian influenza (HPAI) viruses using data at the early stage. Chicken infection experiments by using the wireless node showed that weakness and fever of(More)
In this paper, we propose and demonstrate a new batteryless wireless current sensor node which transmits data using the power charged in a chip capacitor with a current transformer (CT). Since the charging time depends on the current flowing through a power line, the current value can be known by measuring the transmission interval if the node transmits(More)
Here, we report the development of an integrated laser Doppler blood flow micrometer for chickens. This sensor weighs only 18 g and is one of the smallest-sized blood flow meters, with no wired line, these are features necessary for attaching the sensor to the chicken. The structure of the sensor chip consists of two silicon cavities with a photo diode and(More)
In this paper, we present a novel sensor array manufacturing process that involves transfer printing methods using a chip mounter with a vacuum collet. Using these methods, one can mount not only ultra-thin microsensors but also microcontroller and amplifier chips required for sensor device fabrication. We successfully transfer-printed a very fragile(More)
We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a(More)
Since there are cases that chickens infected with highly pathogenic avian influenza (HPAI) viruses die with almost no fever, body-temperature sensing cannot be effective for the early detection of avian influenza (AI) infection in these cases. In addition, sensors directly attached to the body surface are easily affected by their surroundings, therefore it(More)