Doped poly(vinylidene fluoride) as solid polymer electrolyte in nanocrystalline dye-sensitized solar cell

A new solid composite polymer electrolyte was reported by incorporating Azino-bis-(3-ethyl benzo thiazoline-6-sulphonate) ion [ABTS] as dopant in poly(vinylidene flouride) along with redox couple (1-/13-). Under certain conditions, the electrolyte composition forms brush like nano-rods while it is doped with Azino-bis-(3-ethly) benzo thiazoline-6-sulphonate) ion [ABTS], a pi-electron donor. The polymer electrolyte forms nanoscale interpenetrating network with the crystalline order of the polymer electrolyte that seems to be a desirable architecture for the active layer of the photoelectrochemical cell. With this new polymer electrolyte, dye-sensitized solar cell was fabricated using N3 dye absorbed over Ti02- nonoparticles (photoanode) and conducting carbon cement coated on the conducting press (FTO, photocathode). This polymer composite has been successfully used as a promising candidate as solid polymer electrolyte in nanocrystalline dye-sensitized solar cell.

Solid-state nanocrystalline dye-sensitized solar cell using 2-mercapto benzimidazole doped poly(ethylene oxide) as a new polymer electrolyte

New composite doped poly (ethylene oxide) polymer electrolyte was developed using 2-mercapto benzimidazole as plasticizer and iodide/triiodide as redox couple. The fabrication of the cell involves Poly(ethylene oxide)/ 2-mercapto benzimidazole / iodide/triiodide as polymer electrolyte in dye-sensitized solar cell fabricated with N3 dye and TiO2 nanoparticles as the photoanode and Platinum coated FTO (fluorine doped SnO2) as counter electrode. The current-volatage characteristics under simulated sunlight AM1.5 shows a short circuit current Isc of 8.7mA and open circuit photovoltage 508 mV. The conductivity measurements for the new polymer electrolyte and the photoelectrochemical measurments were carried out systematically. In 2-mercapto benzimidazole the electron rich sulphur and nitrogen atoms, act as pi-electron donors that form good interaction with iodine which plays a vital role in the performance of the fabricated dye-sensitized solar cells. The resonance effect increases the stability of the cell to a considerable extent. These results suggest that the new composite polymer electrolyte performs as a promising new doped polymer-electrolyte.

Practising inspired leadership : the use of applied theatre 'prophetical' in the Executive Leadership Development Program for Queensland Health

The Executive Leadership Development Program embarked upon by Queensland Health as a part of the major reform program is discussed. The second stage of the program has begun and the main aim is to ensure leadership development across the organization.

The osteogenic properties of CaP/silk composite scaffolds

The rationale for the present study was to develop porous CaP/silk composite scaffolds with a CaP-phase distribution and pore architecture better suited to facilitate osteogenic properties of human bone mesenchymal stromal cells (BMSCs) and in vivo bone formation abilities. This was achieved by first preparing CaP/silk hybrid powders which were then incorporated into silk to obtain uniform CaP/silk composite scaffolds, by means of a freeze-drying method. The composition, microstructure and mechanical properties of the CaP/silk composite scaffolds were ascertained by X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), scanning electron microscope (SEM) and a universal mechanical testing machine. BMSCs were cultured in these scaffolds and cell proliferation analyzed by confocal microscopy and MTS assay. Alkaline phosphatase (ALP) activity and osteogenic gene expression were assayed to determine if osteogenic differentiation had taken place. A calvarial defect model in SCID mice was used to determine the in vivo bone forming ability of the hybrid CaP/silk scaffolds. Our results showed that incorporating the hybrid CaP/silk powders into silk scaffolds improved both pore structure architecture and distribution of CaP powders in the composite scaffolds. By incorporating the CaP phase into silk scaffolds in vitro osteogenic differentiation of BMSCs was enhanced and there was increased in vivo cancellous bone formation. Here we report a method with which to prepare Ca/P composite scaffolds with a pore structure and Ca/P distribution better suited to facilitate BMSC differentiation and bone formation.

Structure–property relationships of silk-modified mesoporous bioglass scaffolds

Porous mesopore-bioglass (MBG) scaffolds have been proposed as a new class of bone regeneration materials due to their apatite-formation and drug-delivery properties; however, the material’s inherent brittleness and high degradation and surface instability are major disadvantages, which compromise its mechanical strength and cytocompatibility as a biological scaffold. Silk, on the other hand, is a native biomaterial and is well characterized with respect to biocompatibility and tensile strength. In this study we set out to investigate what effects blending silk with MBG had on the physiochemical, drug-delivery and biological properties of MBG scaffolds with a view to bone tissue engineering applications. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were the methods used to analyze the inner microstructure, pore size and morphology, and composition of MBG scaffolds, before and after addition of silk. The effect of silk modification on the mechanical property of MBG scaffolds was determined by testing the compressive strength of the scaffolds and also compressive strength after degradation over time. The drug-delivery potential was evaluated by the release of dexamethasone (DEX) from the scaffolds. Finally, the cytocompatibility of silk-modified scaffolds was investigated by the attachment, morphology, proliferation, differentiation and bone-relative gene expression of bone marrow stromal cells (BMSCs). The results showed that silk modification improved the uniformity and continuity of pore network of MBG scaffolds, and maintained high porosity (94%) and large-pore size (200–400 mm). There was a significant improvement in mechanical strength, mechanical stability, and control of burst release of DEX in silkmodified MBG scaffolds. Silk modification also appeared to provide a better environment for BMSC attachment, spreading, proliferation, and osteogenic differentiation on MBG scaffolds.

Use of micro-ATR/FTIR imaging to study heterogeneous polymer oxidation by direct solvent casting onto the ATR IRE

A technique is described whereby micro-ATR/FTIR imaging can be used to follow polymer degradation reactions in situ in real time. The internal reflection element (IRE) assembly is removed from the ATR objective and polymer is solvent cast directly onto the IRE surface. The polymer is then subjected to degradation conditions and molecular structural changes monitored by periodically replacing the IRE assembly back in the ATR objective and collecting spectra which can be used to construct images. This approach has the benefit that the same part of the sample is always studied, and that contact by pressure which might damage the polymer surface is not required. The technique is demonstrated using the polymer Topas which was degraded by exposure to UVC light in air.

The silk road project : dance and embodiment in the age of motion capture

The Silk Road Project was a practice-based research project investigating the potential of motion capture technology to inform perceptions of embodiment in dance performance. The project created a multi-disciplinary collaborative performance event using dance performance and real-time motion capture at Deakin University’s Deakin Motion Lab. Several new technological advances in producing real-time motion capture performance were produced, along with a performance event that examined the aesthetic interplay between a dancer’s movement and the precise mappings of its trajectories created by motion capture and real-time motion graphic visualisations.

The return of a forgotten polymer : Polycaprolactone in the 21st century

During the resorbable-polymer-boom of the 1970s and 1980s, polycaprolactone (PCL) was used in the biomaterials field and a number of drug-delivery devices. Its popularity was soon superseded by faster resorbable polymers which had fewer perceived disadvantages associated with long term degradation (up to 3-4 years) and intracellular resorption pathways; consequently, PCL was almost forgotten for most of two decades. Recently, a resurgence of interest has propelled PCL back into the biomaterials-arena. The superior rheological and viscoelastic properties over many of its aliphatic polyester counterparts renders PCL easy to manufacture and manipulate into a large range of implants and devices. Coupled with relatively inexpensive production routes and FDA approval, this provides a promising platform for the production of longer-term degradable implants which may be manipulated physically, chemically and biologically to possess tailorable degradation kinetics to suit a specific anatomical site. This review will discuss the application of PCL as a biomaterial over the last two decades focusing on the advantages which have propagated its return into the spotlight with a particular focus on medical devices, drug delivery and tissue engineering.

Mapping a suburb with a single camera using a biologically inspired SLAM system

This paper describes a biologically inspired approach to vision-only simultaneous localization and mapping (SLAM) on ground-based platforms. The core SLAM system, dubbed RatSLAM, is based on computational models of the rodent hippocampus, and is coupled with a lightweight vision system that provides odometry and appearance information. RatSLAM builds a map in an online manner, driving loop closure and relocalization through sequences of familiar visual scenes. Visual ambiguity is managed by maintaining multiple competing vehicle pose estimates, while cumulative errors in odometry are corrected after loop closure by a map correction algorithm. We demonstrate the mapping performance of the system on a 66 km car journey through a complex suburban road network. Using only a web camera operating at 10 Hz, RatSLAM generates a coherent map of the entire environment at real-time speed, correctly closing more than 51 loops of up to 5 km in length.

Persistent navigation and mapping using a biologically inspired SLAM system

The challenge of persistent navigation and mapping is to develop an autonomous robot system that can simultaneously localize, map and navigate over the lifetime of the robot with little or no human intervention. Most solutions to the simultaneous localization and mapping (SLAM) problem aim to produce highly accurate maps of areas that are assumed to be static. In contrast, solutions for persistent navigation and mapping must produce reliable goal-directed navigation outcomes in an environment that is assumed to be in constant flux. We investigate the persistent navigation and mapping problem in the context of an autonomous robot that performs mock deliveries in a working office environment over a two-week period. The solution was based on the biologically inspired visual SLAM system, RatSLAM. RatSLAM performed SLAM continuously while interacting with global and local navigation systems, and a task selection module that selected between exploration, delivery, and recharging modes. The robot performed 1,143 delivery tasks to 11 different locations with only one delivery failure (from which it recovered), traveled a total distance of more than 40 km over 37 hours of active operation, and recharged autonomously a total of 23 times.

The implementation of a novel, bio-inspired, robotic security system

The implementation of a robotic security solution generally requires one algorithm to route the robot around the environment and another algorithm to perform anomaly detection. Solutions to the routing problem require the robot to have a good estimate of its own pose. We present a novel security system that uses metrics generated by the localisation algorithm to perform adaptive anomaly detection. The localisation algorithm is a vision-based SLAM solution called RatSLAM, based on mechanisms within the hippocampus. The anomaly detection algorithm is based on the mechanisms used by the immune system to identify threats to the body. The system is explored using data gathered within an unmodified office environment. It is shown that the algorithm successfully reacts to the presence of people and objects in areas where they are not usually present and is tolerised against the presence of people in environments that are usually dynamic.

Biologically inspired joint control for a humanoid robot

The GuRoo is a 1.2 m tall, 23 degree of freedom humanoid constructed at the University of Queensland for research into humanoid robotics. The key challenge being addressed by the GuRoo project is the development of appropriate learning strategies for control and coordination of the robot's many joints. The development of learning strategies is seen as a way to side-step the inherent intricacy of modeling a multi-DOF biped robot. This paper outlines the approach taken to generate an appropriate control scheme for the joints of the GuRoo. The paper demonstrates the determination of local feedback control parameters using a genetic algorithm. The feedback loop is then augmented by a predictive modulator that learns a form of feed-forward control to overcome the irregular loads experienced at each joint during the gait cycle. The predictive modulator is based on the CMAC architecture. Results from tests on the GuRoo platform show that both systems provide improvements in stability and tracking of joint control.

Biologically inspired visual landmark processing for simultaneous localization and mapping

This paper illustrates a method for finding useful visual landmarks for performing simultaneous localization and mapping (SLAM). The method is based loosely on biological principles, using layers of filtering and pooling to create learned templates that correspond to different views of the environment. Rather than using a set of landmarks and reporting range and bearing to the landmark, this system maps views to poses. The challenge is to produce a system that produces the same view for small changes in robot pose, but provides different views for larger changes in pose. The method has been developed to interface with the RatSLAM system, a biologically inspired method of SLAM. The paper describes the method of learning and recalling visual landmarks in detail, and shows the performance of the visual system in real robot tests.