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Jan-March, 2020


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Silicone versus acrylic resilient long term soft liners; a cross-over clinical study

Mohamed Hussein Abdelnabi and Amal Ali Swelem

ABSTRACT: Objective: The aim of this randomized controlled cross over study was to compare the effect of complete denture renewal using two different long term soft liners namely acrylic-based (ARL) and silicone-based (SRL). Conventional heat cured acrylic resin dentures (CAR) were used as control. Assessed parameters were categorized into objective clinical and subjective patient-centered variables. Clinical parameters were: maximum bite force (MBF) and masticatory efficiency (ME). Patient satisfaction (PS) was evaluated as a patient based outcome. Materials and methods: A total of 30 completely edentulous male patients were initially included in this randomized controlled cross over trial. All subjects already had dentures that lacked retention and stability. Each subject received 3 sets of complete dentures with similar occlusal and polished surfaces. Maxillary complete dentures were fabricated from conventional heat cured acrylic resin. The difference was in the material used in the fitting surface of the mandibular complete dentures: Group (Gp) I (CAR); Gp II (ARL); and Gp III (SRL). The order of the type of prosthesis received by each participant was randomized to achieve a cross over design. Each denture was followed up for 3 months (m) after final adjustment. A capacitive sensor was used to evaluate unilateral MBF. Sieve method was implemented for ME assessment. PS questionnaire evaluated 7 main items (comfort, esthetics, ability to speak, stability, ease of chewing, hygiene maintenance and overall satisfaction) using visual analogue scale. MBF and ME were assessed after 1, 2 and 3 m of denture wear after final adjustment. PS was evaluated 3 m postadjustment. Level of statistical significance was set at p < 0.05. Results: 26 participants concluded the study. Renewed dentures in all groups showed significant improvement in all assessed parameters in comparison to the old prostheses. Improvements were statistically greater in (ARL) and (SRL) in comparison to (CAR) in MBF and ME in addition to 5 items of PS. Differences in esthetics were insignificant. PS was higher with hygiene maintenance in (CAR). Time had no significant effect on the results except after 3 m. (SRL) in comparison to (ARL) showed significantly higher MBF and ME values. The differences in PS values, however, were insignificant. MBF and ME showed significant correlation. Conclusions: Renewal of defective complete dentures improved MBF, ME and PS. (ARL) and (SRL) were superior to (CAR) in MBF, ME and in most of PS outcomes. (CAR) scored better in hygiene maintenance. (SRL) performed better than (ARL) after 3 months in MBF and ME which might indicate better long term results.

[ FULL TEXT PDF 1-11 ] DOI: 10.36632/csi/2020.9.1.1

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The Behaviour of Blind-Bolted Open Sections to Hollow Sections Moment Connections under Static Loading

Abdelrahman M. Fahmy, Associate Prof. Dr. Said Y. Aboul Haggag, Prof. Dr. Abdelrahim K. Dessouki

ABSTRACT: There are many advantages reported as a result of the combination of an open I section connection to a hollow tubular section column. Architects find it useful in many occasions to use structural hollow sections in multi-story constructions, because of their high strength to weight ratio. These connections are easy, with fast installation, fine shape, and simple constitution without the need for field welding. Bolting to the face of the tube is considered one of the remaining areas of difficulty regarding the use of structural hollow sections. Tightening a standard bolt and nut is difficult especially when the walls of hollow sections are relatively thin and welding is not efficient. Recent developments in bolting technology have developed a system that overcomes the complexity involved in the connection between open and hollow sections; Blind-bolting connection. Currently, the main usage of the blind-bolting is shear connections, whereas rigid behaviour may be achieved by fully welded connection. The most famous available blind bolts include BoxBolt, Flowdrill, Huck high strength blind-bolt, Ajax blind bolt, and Lindapter Hollobolt. The aim of this paper is to study the behaviour of open section bolted connections to tubular members under static loading using end plates, to find forces in bolts and their force distribution, the failure modes of the bolts and the end plate.

[ FULL TEXT PDF 12-24 ] DOI: 10.36632/csi/2020.9.1.2

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Modulatory role of creatine in Parkinson's disease

Shaimaa A. ElShebiney, Dalia Abuelfadl and Omar M. Abdel-Salam

ABSTRACT: Creatine is considered a rich dietary supplement that has beneficial antioxidant and neuroprotective role. Its use with Parkinson's disease (PD) is not well verified and needs further investigations. The current study evaluated this supplement in a mouse model of PD respecting motor effects, biochemical changes and pathophysiological modulation. Rotenone (1.5 mg/kg, s.c., day after day for two weeks) was used to induce PD in adult male Swiss mice. Creatine monohydrate was given in two doses (370 and 720 mg/kg, p.o., daily) for 21 days. L-dopa (25 mg/kg, p.o., 21 days) was administered in combination with creatine (370 mg/kg, p.o., daily) to a separate group. The study showed that creatine did not enhance the motor functions but improved the oxidative state and reduced the protein oxidation of striatum. In addition, Striatum paraoxonase and cholinergic activities were restored to normal rate after creatine administration. Creatine also proved added value to conventional L-dopa therapy. In conclusion, creatine dietary supplementation is of ameliorating role to pathophysiological changes associated to PD though motor functions may not be enhanced.

[ FULL TEXT PDF 25-33 ] DOI: 10.36632/csi/2020.9.1.3

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Trapezoidal Surface Plasmonic Polariton for Enhanced Photodetector Efficiency

Hany S. Khalifa, Khalil M. ElKhamisy and Hagar Marouf

ABSTRACT: In this paper, a GaAs photodetector with a thin film trapezoidal surface plasmon polariton (SPP) model structure is studied and analyzed. In comparison with photodetector without SPP, a 3D COMSOL Multiphysics toolbox using the semiconductor model is concerned for explaining the electrical properties, while the optical effect is added with the electromagnetic model. The internal quantum efficiency (IQE) of the model with trapezoidal SPP is improved by 62% compared with the structure without SPP. The maximum terminal current detected in the trapezoidal SPP model is 2.45μA that makes an increase of 1.7 μA, and 66% increase in responsivity achieving a maximum photodetector responsivity is 24 A/W.

[ FULL TEXT PDF 34-41 ] DOI: 10.36632/csi/2020.9.1.4

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