Objectives: The aims of present study were to evaluate nickel and chromium ions concentrations in salivary and serum samples from patients treated with fixed orthodontic appliances and their possible influences on hepatic enzymes. Materials and methods: Saliva and blood samples were collected from 36 patients ranging in age from 12 to 24 years. Three samples of saliva and two samples of blood were obtained. First saliva and blood samples were collected before inserting fixed appliances. Second salivary samples were collected at 1 week, third salivary sample and second blood sample after 4 weeks of appliance insertion. Serum was prepared by centrifuging blood samples at 3000 rpm for 10 minutes. Spectrophotometric determinations were carried out using electrothermal atomic absorption spectrophotometry. Results and conclusion: In serum, significant increase in Ni and Cr ion concentration occurred in samples collected after 4 weeks. In saliva samples, nickel and chromium reached their highest lavels in first week. Mean liver function enzymes SGOT and SGPT were also significantly increased in 4 weeks. Fixed orthodontic appliances release measurable amount of nickel and chromium when placed in mouth, but this increase does not reach toxic levels for nickel and chromium in saliva and serum to cause harmful effects in human beings.
The research work conducted mainly on the reduction reaction of NOx, the oxidation reaction of CO, and hydrocarbons, electro‐catalysis of oxygen in alkaline medium, and photocatalytic water splitting has proved excellent catalytic behavior of perovskite oxides.[16–23] Although only a few reports published usages of the perovskite oxides as catalysts for the organic transformation such as catalytic hydrogenation, Ullmann, Sonogashira reactions, and Suzuki couplings.[24–26] Yoon et al. have prepared K2CO3 based LaMn1‐xCuxO3 perovskite oxide as a potential catalyst and discussed their mechanistic aspects in various reactions occurring at room temperature.[27] Recently, Wu and Ajayan group has demonstrated the relationship between stoichiometry and activity of pure and B‐site substituted layered perovskite oxide in the decomposition reaction of isopropanol by considering Sr2Sn1‐xRuxO4 (0≤x≤1) as catalyst.[28] In this scenario, present work aims to summarize the contribution of perovskite oxides as catalyst in numerous organic syntheses and catalysis, photocatalysis, and electrocatalysis reactions.
Manganese oxide nanoparticles with different crystal phases, morphologies, and structural diversity along with their exceptional properties like high specific surface area, a high fraction of surface atoms, non‐toxic nature, and excellent redox properties are drawing attention for various applications in storage science, especially in the batteries, super‐capacitors, energy conversion, and the environmental catalysis field. Precise control of particle size, morphology, surface area, Mnx+ oxidation state, etc. is the utmost important aspect to explore their application to the full potential. Here, the emphasis is on the recent trends in manganese oxide research – structure, synthesis, and applications. The structure of numerous crystalline phases of manganese oxide nanoparticles are summerized and several facile chemical synthesis processes to achieve the desired crystalline/amorphous structure are discoursed. Temperature and different synthesis conditions dependent phase transformations of β‐MnO2, α‐Mn2O3, and Mn3O4 from α‐MnO2 are discussed as well. The pragmatic approach directs that the application field is mostly controlled by the morphologies.
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