Carboxymethyl chitosan-graft-phosphatidylethanolamine: amphiphilic matrices for controlled drug delivery

Modified carboxymethyl chitosan (CMC) containing phosphatidylethanolamine (PEA) groups were synthesized by a 1- ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)-mediated coupling reaction. The structure of the modified CMC exhibiting an amphiphilic character was analysed by FT-IR and 1H NMR. CMC-g-PEA beads were prepared with sodium tripolyphosphate (TPP) by ionic-crosslinking. The beads sizes were in range from 800 to 1200 lm and encapsulation efficiencies of drug were more than 68%. The morphologies of CMC-g-PEA beads were examined with scanning electron microscopy (SEM). The release experiments were performed using ketoprofen as an hydrophobic model drug. The drug dissolution kinetics showed longer release times for CMC-g-PEA beads: 20 h (at pH 1.4) and 45 h (at pH 7.4). The amount of the drug release was much higher in acidic solution than in basic solution due to the swelling properties of the matrix at acidic pH. These results suggest that modified CMC with PEA may become a potential delivery system to control the release of hydrophobic drugs

Graft copolymerized chitosan : present status and applications

Chitosan is a natural based polymer obtained by alkaline deacetylation of chitin, exhibiting excellent biological properties such as biodegradation in the human body, and immunological, antibacterial, and wound-healing activity. Chitosan has also been found to be a good candidate as a support material for gene delivery, cell culture and tissue engineering. However, practical use of chitosan has been mainly confined to the unmodified forms. For a breakthrough in utilization, graft copolymerization onto chitosan will be a key point, which will introduce desired properties and enlarge the field of the potential applications of chitosan by choosing various types of side chains. This article reviews the various methods such as free radical, radiation, enzymatic and cationic graft copolymerization onto chitosan, the factors influencing on the grafting parameters such as grafting percentage and grafting efficiency, and the properties of grafted chitosan. This review also screens the current applications of graft copolymerized chitosans in the field of drug delivery, tissue engineering, antibacterial, biomedical, metal adsorption and dye removal

Positioning and Surveying Requirements for Exploration and Exploitation of Ocean Wealth

Deep sea mining, such as is now being planned to be carried out in the Indian Ocean, requires an accurate positioning system for navigation and for the control of the equipment. Short range systems using electromagnetic principles cover only a limited area while the longer range systems which can be used for offshore, deep ocean work although covering large areas, have limited accuracy. This paper reviews the requirements for position fixing systems for deep ocean mining and the ways to reach the best solution at the most reasonable cost

A photovoltaic system using supercapacitor energy storage for power equilibrium and voltage stability

In a photovoltaic system, a stable voltage and of tolerable power equilibrium is needed. Hence, a dedicated analog charge controller for a storage system which controls energy flow to impose power equilibrium, and therefore, voltage stability on the load is required. We demonstrate here our successful design considerations employing supercapacitors as main energy storage as well as a buffer in a standalone photovoltaic system, incorporating a dedicated supercapacitor charge controller for the first time. Firstly, we demonstrated a photovoltaic system employing supercapacitors as main energy storage as well as a buffer in a standalone photovoltaic system. Secondly, we design a constant voltage maximum power point tracker (MPPT) for peak power extraction from the photovoltaic generator. Thirdly, we incorporated a supercapacitor charge controller for power equilibrium and voltage stability through a dedicated analog charge controller in our design, the first of its kind. Fourthly, we analyzed the use of supercapacitor storage to mitigate disequilibrium between power supply and demands, which, in turn, causes overvoltage or under voltage across the load. Lastly, we then went ahead to demonstrate the control of the energy flow in the system so as to maintain rated voltage across a variant demand load

The Qualitative Role of Big data and Internet of Things for Future Generation-A Review

The Internet of Things (IoT) wireless LAN in healthcare has moved away from traditional methods that include hospital visits and continuous monitoring. The Internet of Things allows the use of certain means, including the detection, processing and transmission of physical and biomedical parameters. With powerful algorithms and intelligent systems, it will be available to provide unprecedented levels of critical data for real-time life that are collected and analyzed to guide people in research, management and emergency care. This chapter provides a quick overview of IoT features and how they relate to wireless discovery and technology to deploy the medical applications you need. In the world, the revolution in any industry is to connect your products and devices to the Internet and make them independent and remotely connected, so that anyone can use and view them from anywhere and anytime. The Internet of Things provides us with a home automation system that uses smart devices to overcome this obstacle, allowing us to easily manage our appliances. A smart city is a vision to integrate a variety of information and communication solutions for residents with essential services, such as smart parking on all streets. The main motivation for using the Internet for parking objects is simply collecting data to get free parking. The IoT-based RTSSPS architecture is divided into three parts: a WSN-based smart street parking module, an IoT-based smart street parking module, and an IoT-based smart street parking module. IoT-based cloud with street parking algorithm, rating and future directions

Radio Frequency Energy Harvesting and Management for Wireless Sensor Networks

Radio Frequency (RF) Energy Harvesting holds a promising future for generating a small amount of electrical power to drive partial circuits in wirelessly communicating electronics devices. Reducing power consumption has become a major challenge in wireless sensor networks. As a vital factor affecting system cost and lifetime, energy consumption in wireless sensor networks is an emerging and active research area. This chapter presents a practical approach for RF Energy harvesting and management of the harvested and available energy for wireless sensor networks using the Improved Energy Efficient Ant Based Routing Algorithm (IEEABR) as our proposed algorithm. The chapter looks at measurement of the RF power density, calculation of the received power, storage of the harvested power, and management of the power in wireless sensor networks. The routing uses IEEABR technique for energy management. Practical and real-time implementations of the RF Energy using Powercast harvesters and simulations using the energy model of our Libelium Waspmote to verify the approach were performed. The chapter concludes with performance analysis of the harvested energy, comparison of IEEABR and other traditional energy management techniques, while also looking at open research areas of energy harvesting and management for wireless sensor networks.Comment: 40 pages, 9 figures, 5 tables, Book chapte

Processing and characterization of chitosan microspheres to be used as templates for layer-by-layer assembly

Chitosan (Ch) microspheres have been developed by precipitation method, cross-linked with glutaraldehyde and used as a template for layer-by-layer (LBL) deposition of two natural polyelectrolytes. Using a LBL methodology, Ch microspheres were alternately coated with hyaluronic acid (HA) and Ch under mild conditions. The roughness of the Ch-based crosslinked microspheres was characterized by atomic force microscopy (AFM). Morphological characterization was performed by environmental scanning electron microscopy (ESEM), scanning electron microscopy (SEM) and stereolight microscopy. The swelling behaviour of the microspheres demonstrated that the ones with more bilayers presented the highest water uptake and the uncoated cross-linked Ch microspheres showed the lowest uptake capability. Microspheres presented spherical shape with sizes ranging from 510 to 840 lm. ESEM demonstrated that a rougher surface with voids is formed in multilayered microspheres caused by the irregular stacking of the layers. A short term mechanical stability assay was also performed, showing that the LBL procedure with more than five bilayers of HA/Ch over Ch cross-linked microspheres provide higher mechanical stability