How long does treatment with fixed orthodontic appliances last? A systematic review

INTRODUCTION There is little agreement on the expected duration of a course of orthodontic treatment; however, a consensus appears to have emerged that fixed appliance treatment is overly lengthy. This has spawned numerous novel approaches directed at reducing the duration of treatment, occasionally with an acceptance that occlusal outcomes may be compromised. The aim of this study was to determine the mean duration and the number of visits required for comprehensive orthodontic treatment involving fixed appliances. METHODS Multiple electronic databases were searched with no language restrictions, authors were contacted as required, and reference lists of potentially relevant studies were screened. Randomized controlled trials and nonrandomized prospective studies concerning fixed appliance treatment with treatment duration as an outcome measure were included. Data extraction and quality assessment were performed independently and in duplicate. RESULTS Twenty-five studies were included after screening: 20 randomized controlled trials and 5 controlled clinical trials. Twenty-two studies were eligible for meta-analysis after quality assessment. The mean treatment duration derived from the 22 included studies involving 1089 participants was 19.9 months (95% confidence interval, 19.58, 20.22 months). Sensitivity analyses were carried out including 3 additional studies, resulting in average duration of treatment of 20.02 months (95% confidence interval, 19.71, 20.32 months) based on data from 1211 participants. The mean number of required visits derived from 5 studies was 17.81 (95% confidence interval, 15.47, 20.15 visits). CONCLUSIONS Based on prospective studies carried out in university settings, comprehensive orthodontic treatment on average requires less than 2 years to complete

A Web Based Approach to Virtual Appliance Creation, Programming and Management

The Internet and Web technology is advancing at a frantic pace, expanding into almost every aspect of our everyday life. One of the latest scientific activities for the Internet and the Web is the so-called pervasive or ubiquitous computing where networking plays a vital role in its core computational framework. In this, people are able to use the Internet and Web to manage the operation of embedded network devices, services and to coordinate their services in ways that create applications such as smart-homes, smart-offices, smart-cars etc, collectively referred to as intelligent environments. For ordinary people (non technologists) to be able to use this technology, it is required that the interaction between the users and the environment must be as transparent and simple as possible, employing intuitive and user-friendly interfaces wherever possible. A popular approach to empowering users to customise the functionality of their environments is via end-user programming. In this work-in-progress paper we describe an approach based on using a web based GUI to augment earlier work of ours concerning an end user programming paradigm known as Pervasive interactive Programming (PiP), in a way that makes it more flexible and easy to use. By doing this, we present a conceptual model and discuss the issues in developing and using this model. © 2010 IEEE

Harmonic Reduction of a Single-Phase Multilevel Inverter Using Genetic Algorithm and Particle Swarm Optimization

Power inverter play an important role in power system especially with its capability on reducing system size and increase efficiently. The recent research trends of power electronic system are focusing on multilevel inverter topics in optimization on voltage output, reducing the total harmonics distortion, modulation technique, and switching configuration. The research emphasizes the optimization with a fundamental switching frequency method that is the optimized harmonic stepped waveform (OHSW) modulation method. The selective harmonic elimination (SHE) calculation has adapted with genetic algorithm (GA) and particle swarm optimization (PSO) in order to speed up the calculation. Both bioinspired algorithms are compared in terms of total harmonic distortion (THD) and selective harmonic elimination for both equal and unequal sources. The overall result showed that both algorithms have high accuracy in solving the nonlinear equation. However, the genetic algorithm showed better output quality in terms of selective harmonic elimination which overall no exceeding 0.4%. Particle swarm optimization shows strength in finding the best total harmonic distortion where in seven-level cascaded H-bridge multilevel inverter (m=0.8) shows 6.8% only as compared to genetic algorithm. Simulation for three-level, five-level, and seven-level for each multilevel inverter at different circumferences had been done in this research. The result draws out a conclusion where the possibility of having a filterless high-efficient inverter can be achieved

BRB System Out-of-Plane Considerations

This paper describes a simple method for BRB system design considering BRB stability and frame out-ofplane deformation effects. The method seeks to prevent yielding in the BRB system except for in the core within the BRB restrainer/casing, and it uses standard equations with which engineers are familiar. The method discourages brace/gusset plate regions which are too flexible, where instability may occur as a result of axial force, or which are too stiff, where yielding may occur due to out-of-plane frame deformations thereby compromising the performance in later in-plane deformation cycles. The need to explicitly consider column twist restraint in the design procedure is emphasized

Molecular orientation-dependent energetic shifts in solution-processed non-fullerene acceptors and their impact on organic photovoltaic performance

The non-fullerene acceptors (NFAs) employed in state-of-art organic photovoltaics (OPVs) often exhibit strong quadrupole moments which can strongly impact on material energetics. Herein, we show that changing the orientation of Y6, a prototypical NFA, from face-on to more edge-on by using different processing solvents causes a significant energetic shift of up to 210 meV. The impact of this energetic shift on OPV performance is investigated in both bilayer and bulk-heterojunction (BHJ) devices with PM6 polymer donor. The device electronic bandgap and the rate of non-geminate recombination are found to depend on the Y6 orientation in both bilayer and BHJ devices, attributed to the quadrupole moment-induced band bending. Analogous energetic shifts are also observed in other common polymer/NFA blends, which correlates well with NFA quadrupole moments. This work demonstrates the key impact of NFA quadruple moments and molecular orientation on material energetics and thereby on the efficiency of high-performance OPVs