Background: The formation of white spot lesions around fixed orthodontic attachments is a common complication during and after fixed orthodontic treatment, which hinders the result of a successfully completed orthodontic treatment. The aim of the study was to assess the effectiveness of the Caries Infiltrant (ICON®) on prevention of caries on the smooth enamel surface when applied alone or combined with conventional adhesives. Materials and methods: Seventy eight human premolar enamel discs were randomly assigned to six groups (n=13). The discs were etched and treated with resins of different monomer content forming the following groups: (1)Untreated etched samples served as the negative control, (2) ICON® (DMG), (3) Adper™ SB 2 (3M ESPE), (4) Heliobond (IvoclarVivadent), (5) ICON®+ Adper™ SB 2 and (6) ICON®+ Heliobond. Specimens were subjected to demineralization by immersion in hydrochloric acid (pH 2.6) for 18 days. Calcium dissolution into the acid was assessed by photometric test via spectrophotometer at 24 hour intervals. Results: The results revealed that, there was a highly significant difference between the sealed groups and the unsealed (untreated) one (p≤0.00) indicating that the unsealed specimens showed the highest amount of Ca ion loss among all other groups. Additionally, there was no significant difference between untreated specimens and the ICON® sealed ones. While, Heliobond decreased the Ca ion loss significantly compared to the untreated specimens and Adper™ SB 2 performed significantly better than both ICON® and Heliobond. Furthermore, the combination of ICON® with either Adper™ SB 2 or Heliobond served as the best protective measures and maintained the protective effect during the whole experiment period. Therefore, within the limitations of this in vitro study, it could be concluded that the use of Caries Infiltrant prior to the application of the tested conventional adhesives increases their protective effect against demineralization.
We demonstrate that the selective hydrogenation of acetylene depends on energy profile of the partial and full hydrogenation routes and the thermodynamic stability of adsorbed C2H2 in comparison to C2H4.
The mechanism of the electronic flow rate at Al-TiO2 interfaces system has been studied using the postulate of electronic quantum theory. The different structural of two materials lead to suggestion the continuum energy level for Al metal and TiO2 semiconductor. The electronic flow rate at the Al-TiO2 complex has affected by transition energy, coupling strength and contact at the interface of two materials. The flow charge rate at Al-TiO2 is increased by increasing coupling strength and decreasing transition energy.
Biomass is a popular renewable carbon source because it has a lot of potential as a substitute for scarce fossil fuels and has been used to make essential compounds like 5-hydroxymethylfurfural (HMF). One of the main components of biomass, glucose, has been extensively studied as a precursor for the production of HMF. Several efforts have been made to find efficient and repeatable procedures for the synthesis of HMF, a chemical platform used in the manufacturing of fuels and other high-value compounds. Sulfonated graphite (SG) was produced from spent dry batteries and utilized as a catalyst to convert glucose to 5-hydroxymethylfurfural (HMF). Temperature, reaction time, and catalyst loading were the variables studied. When dimethyl sulfo
... Show MoreThe presence of antibiotic residues such as ciprofloxacin (CIPR) in an aqueous environment is dangerous when their concentrations exceed the allowable. Therefore, eliminating these residues from the wastewater becomes an essential issue to prevent their harm. In this work, the potential of efficient adsorption of ciprofloxacin antibiotics was studied using eco-friendly ZSM-5 nanocrystals‑carbon composite (NZC). An inexpensive effective natural binder made of the sucrose-citric acid mixture was used for preparing NZC. The characterization methods revealed the successful preparation of NZC with a favorable surface area of 103.739 m2/g, and unique morphology and functional groups. Investigating the ability of NZC for adsorbing CIPR antibioti
... Show MoreIn this research, CNRs have been synthesized using pyrolysis of plastic waste(pp) at 1000 ° C for one hour in a closed reactor made from stainless steel, using magnesium oxide (MgO) as a catalyst. The resultant carbon nano rods were purified and characterized using energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD). The surface characteristics of carbon rods were observed with the Field emission scanning electron microscopy (FESEM). The carbon was evenly spread and had the highest concentration from SEM-EDX characterization. The results of XRD and FESEM have shown that carbon Nano rods (CNRs) were present in Nano figures, synthesized at 1000 ° C and with pyrolysis temperature 400° C. One of t
... Show MoreFor more than a decade, externally bonded carbon fiber reinforced polymer (CFRP) composites successfully utilized in retrofitting reinforced concrete structural elements. The function of CFRP reinforcement in increasing the ductility of reinforced concrete (RC) beam is essential in such members. Flexural and shear behaviors, ductility, and confinement were the main studied properties that used the CFRP as a strengthening material. However, limited attention has been paid to investigate the energy absorption of torsion strengthening of concrete members, especially two-span concrete beams. Hence, the target of this work is to investigate the effectiveness of CFRP-strengthening technique with regard to energy absorption of two-span RC
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