Abstract-This paper presents a sensor-based pedestrian tracking technology that does not rely on any infrastructure. The information about human walking is monitored by a sensor module composed of accelerometers, gyroscopes and magnetometers. The acquired information is used by an algorithm proposed in this paper to accurately compute the position of a pedestrian. Through the application of human kinetics, the algorithm integrates two traditional technologies: strap-down inertial navigation and pedestrian dead-reckoning. Based on the algorithm, this paper presents several methods to improve the accuracy of pedestrian tracking through reducing the integral drift which is the main cause of errors in inertial navigation. These methods have been carefully investigated through theoretical study, simulation and field experiment. The results indicate accurate tracking is achievable through the application of both the proposed algorithm and methods. Evidently, it is feasible to develop self-contained pedestrian tracking system using inertial/magnetic sensors, eliminating the need for complicated and normally expensive infrastructure that most existing tracking systems rely on.Index Terms-Human walking, inertial navigation system (INS), integral drift, pedestrian dead reckoning (PDR), pedestrian tracking, sensor module.
Late embryogenesis abundant (LEA) group 4 (LEA4) proteins play an important role in the water stress tolerance of plants. Although they have been hypothesized to stabilize macromolecules in stressed cells, the protective functions and mechanisms of LEA4 proteins are still not clear. In this study, the metal binding properties of two related soybean LEA4 proteins, GmPM1 and GmPM9, were tested using immobilized metal ion affinity chromatography (IMAC). The metal ions Fe(3+), Ni(2+), Cu(2+) and Zn(2+) were observed to bind these two proteins, while Ca(2+), Mg(2+) or Mn(2+) did not. Results from isothermal titration calorimetry (ITC) indicated that the binding affinity of GmPM1 for Fe(3+) was stronger than that of GmPM9. Hydroxyl radicals generated by the Fe(3+)/H(2)O(2) system were scavenged by both GmPM1 and GmPM9 in the absence or the presence of high ionic conditions (100 mM NaCl), although the scavenging activity of GmPM1 was significantly greater than that of GmPM9. These results suggest that GmPM1 and GmPM9 are metal-binding proteins which may function in reducing oxidative damage induced by abiotic stress in plants.
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