Bonded amalgam as a fissure sealant in low-income setting: A randomised controlled trial

Objectives: To compare one year retention rate of bonded amalgam sealants (BAS) with that of conventional resin-based sealant (RBS). Methods: It was a parallel group, equivalence, randomised controlled trial done during March 2018 to December 2019 at the dental clinics of Dow University of Health Sciences, and the Jinnah Sind Medical University, Karachi, Pakistan on children aged 12-16 years, who were randomly assigned to one of the two treatment groups (BAS vs. RBS). Complete retention of the sealant at one year follow-up was labeled as success. Multi-level mixed effect logistic regression model was employed. Study was registered at www.clinicaltrials.gov # NCT NCT03130725. Results: There were 137 teeth (23 subjects) in the BAS and 128 teeth (15 subjects) in the RBS group that were evaluated for sealant retention at 12 months follow-up. Among the BAS group, 100/137 (73%) sealants were completely retained whereas 110/128 (86%) were fully retained in the RBS group. Nearly, 22/137 (16%) BAS and 10/128 (7.8%) RBS were completely dislodged. In multivariable analysis, subject age \u3e15 years and male gender were found to be significantly associated with the dislodgement of sealants. Conclusions: At 12 months follow-up, the retention of bonded amalgam sealant (BAS) was significantly lower than that of the resin-based sealant (RBS)

Planar SIW leaky wave antenna with electronically reconfigurable E-and H-plane scanning

This paper reports on a novel technique of switching radiation characteristics electronically between E-and H-planes of planar Substrate Integrated Waveguide Leaky Wave Antennas (SIW-LWAs). The leaky wave mode is achieved through increasing the pitch of bounding metallic via posts on one side of SIW transmission section. The radiation switching is achieved by extending the top and bottom metallic planes to a distance of 1 mm along the leakage side. The extended section acts as a parallel plate section which is conveniently connected or disconnected from the leaking side of SIW through PIN diodes. The ‘ON’ state of PIN diodes extends the metal guides and results in the H-plane leakage whereas ‘OFF’ state of PIN diodes truncates the extended metal earlier and alter the leakage line boundary condition towards E-plane. The whole concept is validated by series of simulations followed by the realization and testing of the SIW-LWA. The measured radiation pattern scans about 54° in the E-plane between 10.0 GHz to 11.7 GHz, and 58° in the H-plane from 9 GHz to 10.6 GHz. The proposed topology is a suitable candidate for remote sensing and airborne applications

Characterization of PTFE Film on 316L Stainless Steel Deposited through Spin Coating and Its Anticorrosion Performance in Multi Acidic Mediums

Polytetrafluoroethylene (PTFE) was coated on 316L stainless steel (SS) substrate through a spin coating technique to enhance its corrosion resistance properties in hydrochloric acid (HCl) and nitric acid (HNO3) medium. Scanning electron microscopy (SEM) revealed the morphology of the coated and uncoated substrates and showed a uniform and crack-free PTFE coating on 316L SS substrate, while a damaged surface with thick corrosive layers was observed after the electrochemical test on the uncoated sample. However, an increased concentration of HCl and HNO3 slightly affected the surface morphology by covering the corrosive pits. An atomic force microscope (AFM) showed that the average surface roughness on 316L SS and PTFE coating was 26.3 nm and 24.1 nm, respectively. Energy dispersive X-ray spectroscopy (EDS) was used for the compositional analysis, which confirmed the presence of PTFE coating. The micro Vickers hardness test was used to estimate the hardness of 316L SS and PTFE-coated substrate, while the scratch test was used to study the adhesion properties of PTFE coating on 316L SS. The anticorrosion measurements of 316L SS and PTFE-coated substrates were made in various HCl and HNO3 solutions by using the electrochemical corrosion test. A comparison of the corrosion performance of PTFE-coated substrate with that of bare 316L SS substrate in HCl medium showed a protection efficiency (PE) of 96.7%, and in the case of HNO3 medium, the PE was 99.02%, by slightly shifting the corrosion potential of the coated sample towards the anodic direction

Mechanism of Fatigue Crack Growth in Biomedical Alloy Ti-27Nb

Implants are widely used in the human body for the replacement of affected bones. Fatigue failure is one of the serious concerns for implants. Therefore, understanding of the underlying mechanism leading to fatigue failure is important for the longevity of biomaterial implants. In this paper, the fracture toughness and fatigue crack growth of titanium alloy biomaterial Ti-27Nb has been experimentally investigated. The Ti-27Nb material is tested for fatigue crack growth in different environmental conditions representing the ambient and in vitro environments for 504 hours and 816 hours, respectively. Fractography of the tested specimen is conducted using Scanning Electron Microscope (SEM). The results of the fatigue crack growth propagation of the ambient and in vitro samples are similar in the Paris crack growth region. However, in the threshold region, the crack growth rate is higher for the Simulated Body Fluid (SBF) treated specimen. The fracture surface morphology of in vitro samples shows brittle fracture as compared to ambient specimens with significant plasticity and striations marks. It is proposed that a similar investigation may be conducted with specimens treated in SBF for prolonged periods to further ascertain the findings of this study

Proceedings of International Web Conference in Civil Engineering for a Sustainable Planet

This proceeding contains articles of the various research ideas of the academic community and practitioners accepted at the "International Web Conference in Civil Engineering for a Sustainable Planet (ICCESP 2021)". ICCESP 2021 is being Organized by the Habilete Learning Solutions, Kollam in Collaboration with American Society of Civil Engineers (ASCE), TKM College of Engineering, Kollam, and Baselios Mathews II College of Engineering, Kollam, Kerala, India. Conference Title: International Web Conference in Civil Engineering for a Sustainable PlanetConference Acronym: ICCESP 2021Conference Date: 05–06 March 2021Conference Location: Online (Virtual Mode)Conference Organizer: Habilete Learning Solutions, Kollam, Kerala, IndiaCollaborators: American Society of Civil Engineers (ASCE), TKM College of Engineering, Kollam, and Baselios Mathews II College of Engineering, Kollam, Kerala, India