SYNTHESIS AND IMPLEMENTATION OF NiZnFe 2 O 4 FERRITES TO DESIGN EMBEDDED SYSTEM FOR HUMIDITY MEASUREMENT
2 ABSTRACT: Along with magnetic properties, the spinel ferrites exhibit promising electrical properties, deployment of which results into evolution of new area of applications as the electronic sensor materials. The electrical properties significantly depend upon the environmental compositions, for which it has been exposed. The electrical resistance of these sensor materials varies not only with gas concentration but also with change in water vapour concentration. With the view to develop an embedded technology based smart sensor module for humidity measurement a sensor material NixZn1-xFe2O4 are synthesized by chemical method and characterized by XRD and IR tools. The x-ray powder diffraction reveals the formation of single phase spinel ferrite, which is also supported by the IR absorption bands attributed to tetrahedral (A) site and octahedral (B) sites. Employing embedded philosophy, the sensor module is designed about AVR ATmega8L microcontroller for humidity measurement. The thick film of materials under investigation, prepared by screen painting technique, is used to sense the concentration of water molecules. Analog part of the system is wired about highly precise instrumentation amplifier AD620. Deployment of on-chip ADC of 10-bit resolution causes to increase in the preciseness of the results. The system is calibrated to the humidity in RH%. The data shown by the system under investigation reveals close match with the standard data.
Liquid-Phase Synthesis of Nickel Nanoparticles stabilized by PVP and study of their structural and magnetic properties
We have synthesized nickel nanoparticles using nickel chloride as a precursor in ethanol using PVP (Poly Vinyl Pyrrolidone) as a surfactant and hydrazine hydrate as reducing agent at 60 °C in a facile manner. The structural analysis showed that particles are face-centered cubic and monodisperse within the PVP matrix with average size about 3 nm. The magnetic analysis shows the superparamagnetism of the single-domain nickel nanoparticles with the blocking temperature (Tb) exists around 14 K with clear hysteretic effect observation below this blocking temperature. Copyright © 2011 VBRI press.
An injectable and thermosensitive hydrogel: Promoting periodontal regeneration by controlled-release of aspirin and erythropoietin.
Periodontitis is an inflammatory disease induced by complex interactions between host immune system and plaque microorganism. Alveolar bone resorption caused by periodontitis is considered to be one of the main reasons for tooth loss in adults. To terminate the alveolar bone resorption, simultaneous anti-inflammation and periodontium regeneration is required, which has not appeared in the existing methods. In this study, chitosan (CS), β-sodium glycerophosphate (β-GP), and gelatin were used to prepare an injectable and thermosensitive hydrogel, which could continuously release aspirin and erythropoietin (EPO) to exert pharmacological effects of anti-inflammation and tissue regeneration, respectively. The releasing profile showed that aspirin and EPO could be continuously released from the hydrogels, which exhibited no toxicity both in vitro and in vivo, for at least 21 days. Immunohistochemistry staining and micro-CT analyses indicated that administration of CS/β-GP/gelatin hydrogels loaded with aspirin/EPO could terminate the inflammation and recover the height of the alveolar bone, which is further confirmed by histological observations. Our results suggested that CS/β-GP/gelatin hydrogels are easily prepared as drug-loading vectors with excellent biocompatibility, and the CS/β-GP/gelatin hydrogels loaded with aspirin/EPO are quite effective in anti-inflammation and periodontium regeneration, which provides a great potential candidate for periodontitis treatment in the dental clinic. Statement of Significance To terminate the alveolar bone resorption caused by periodontitis, simultaneous anti-inflammation and periodontium regeneration is required, which has not appeared in the existing methods. Here, (1) the chitosan (CS)/β-sodium glycerophosphate/gelatin hydrogels loaded with aspirin/erythropoietin (EPO) can form at body temperature in 5 min with excellent biocompatibility in vitro and in vivo; (2) The faster release of aspirin than EPO in the early stage is beneficial for anti-inflammation and provides a microenvironment for ensuring the regeneration function of EPO in the following step. In vivo experiments revealed that the hydrogels are effective in the control of inflammation and regeneration of the periodontium. These results indicate that our synthesized hydrogels have a great potential in the future clinical application.