Acrylic Resin Guide for Locating the Abutment Screw Access Channel of Cement-Retained Implant Prostheses

Abutment screw loosening represents a common and challenging technical complication of cement-retained implant prostheses. This article describes the fabrication of a simple and accurate poly(methyl methacrylate) guide for identifying the location and angulation of the abutment screw access channel of a cement-retained implant prosthesis with a loosened abutment screw

Uptake of divalent manganese from aqueous solution using cation exchange resins

The present work deals with the removal of highly toxic manganese ion from aqueous solution using cation exchange resins namely, Amberjet 1500H, Amberjet 1300H and Amberlite IRC86. The study was carried out in media of various ionic strengths (1.98-9.98 mmol/L), different resin dose (0.25-8.0 gm) and a wide solution acidity range (0.001-1.0 M), in addition to at three temperatures (293-318 K).The aim of this study was to understand the mechanisms that govern manganese removal and find a suitable equilibrium isotherm and kinetic model for the manganese removal in a batch reactor. The experimental isotherm data were analyzed using the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) equations. The experimental data were analyzed using four adsorption kinetic models – the pseudo first- and second-order, intraparticle diffusion and the Elovich equations – to determine the best fit equation for the adsorption of manganese ions onto the resins. The rate constants, equilibrium capacities and related correlation coefficients for each kinetic model were calculated and discussed. Also, predicted qt values from the kinetic equations were compared with the experimental data. Thermodynamic parameters, involving ΔH, ΔS and ΔG were also calculated from graphical interpretation of the experimental dat

Dual Output Power Management Unit for PV-Battery Hybrid Energy System

The tremendous evolution in the electronics industry has provided high performance portable devices. However, the high power demand and the limited capacity of batteries, prevent the devices from operating for a long time without the need of a power outlet. The ease of deploying Photovoltaic (PV) cells close to the device enables the user to harvest energy on the go, and get rid of the conventional power outlets. However, applying the PV power to the electronic devices is not as easy as the plug and play model, due to the unstable output voltage and power of the PV cells. In this thesis, a power management unit is proposed to provide dual regulated outputs using a PV module and a rechargeable battery. The main components of the unit are a Dual Input Multiple Output (DIMO) DC-DC converter and a digital controller. The converter is used to interface the battery and the PV module with the loads. Moreover, the proposed converter has the ability to step up or step down the input voltage. The controller maximizes the PV power using the fractional open circuit voltage Maximum Power Point Tracking (MPPT) method. Furthermore, the controller manages the amount of power supplied to or from the battery in order to satisfy the load demand and regulate the outputs at the required levels. The controller has been implemented and synthesized using VHDL. A prototype has been implemented using an FPGA and off the shelf components. The functionality of the system has been tested and verified under varying environmental conditions

Improved Spectrum Mobility using Virtual Reservation in Collaborative Cognitive Radio Networks

Cognitive radio technology would enable a set of secondary users (SU) to opportunistically use the spectrum licensed to a primary user (PU). On the appearance of this PU on a specific frequency band, any SU occupying this band should free it for PUs. Typically, SUs may collaborate to reduce the impact of cognitive users on the primary network and to improve the performance of the SUs. In this paper, we propose and analyze the performance of virtual reservation in collaborative cognitive networks. Virtual reservation is a novel link maintenance strategy that aims to maximize the throughput of the cognitive network through full spectrum utilization. Our performance evaluation shows significant improvements not only in the SUs blocking and forced termination probabilities but also in the throughput of cognitive users.Comment: 7 pages, 10 figures, IEEE ISCC 201

Prosthetic Rehabilitation Following Lateral Resection of the Mandible with a Long Cantilever Implant-Supported Fixed Prosthesis: A 3-Year Clinical Report

This clinical report describes the prosthetic management of the surgical reconstruction of a patient after mandibular resection. Complete oral rehabilitation was achieved with a maxillary complete denture and a mandibular implant-supported fixed prosthesis with a custom titanium framework and a long unilateral cantilever

Rhamnus prinoides (gesho) extract Inhibits Streptococcus mutans and Candida albicans Polymicrobial Biofilm Formation

Polymicrobial biofilms contain multiple microbial species encased in an extracellular polymeric matrix. Synergistic interactions within polymicrobial biofilms contribute to elevated antibiotic resistance and chronic infections; furthermore, prevention and treatment is still an unresolved issue. The yeast Candida albicans and the Gram positive bacterium Streptococcus mutans are biofilm-forming oral pathogens that interact mutualistically, and were investigated in this work. Crystal violet-based biofilm formation assays were used to measure the effect of extracts from Rhamnus prinoides (gesho), an East African plant used in traditional medicine, on biofilm formation. The biomass of dual species biofilms was 70% greater than single-species biofilms, indicating a synergistic interaction. Treatment with gesho extracts reduced both single-species and polymicrobial biofilm biomass by more than 90% relative to controls. Imaging by epifluorescence microscopy supported the findings of the biofilm formation assays. In conclusion, gesho exhibited significant potential for use as an anti-biofilm agent and warrants further investigation

Improving Building Performance through Integrating Constructability in the Design Process

The traditional procurment approaches commonly adopted in construction projects and the involvement of multitude of various project participants with diverse objectives, skills and interests tended to separate design from construction.This separation obstructs contractors from providing designers with construction feedback and suggestions for design improvement, which ultimately hampers the improvement of building performance. Because of the importance of the design phase and the vital role played by contractors in the construction industry, this paper aims to investigate the integration of construction knowledge and contractor’s experience in the design process as an approach for improving building performance. In order to achieve this aim, a research methodology is designed to accomplish four objectives. Firstly, reviewing the nature of the construction industry;constructability; architecture and the design process and measuring building performance. Secondly, presenting case studies of successful projects benefited from applying the concept of constructability during the design process. Thirdly, developing an innovative framework to facilitate the integration of construction knowledge and contractor’s experience in the design process and establishing the strategies that support its application. Finally, summarising research conclusions and recommendations useful to construction professionals and further research. Findings of the research showed that integrating the concept of constructability during the design process improves building performance (e.g. reducing construction time, cost and waste as well as improving quality and productivity) and enhances the relationships between project participants. The research adds a valuable contribution to the built environment body of knowledge through presenting a practical approach for integrating construction knowledge and contractor’s experience in the design process

An approach for cross-modality guided quality enhancement of liver image

A novel approach for multimodal liver image contrast enhancement is put forward in this paper. The proposed approach utilizes magnetic resonance imaging (MRI) scan of liver as a guide to enhance the structures of computed tomography (CT) liver. The enhancement process consists of two phases: The first phase is the transformation of MRI and CT modalities to be in the same range. Then the histogram of CT liver is adjusted to match the histogram of MRI. In the second phase, an adaptive histogram equalization technique is presented by splitting the CT histogram into two sub-histograms and replacing their cumulative distribution functions with two smooths sigmoid. The subjective and objective assessments of experimental results indicated that the proposed approach yields better results. In addition, the image contrast is effectively enhanced as well as the mean brightness and details are well preserved