Galvanic Corrosion and Ion Release from Different Orthodontic Brackets and Wires in Acidic Artificial Saliva

Objective: Corrosion resistance is among the most important properties of metal alloys used in the oral cavity. Consumption of acidic foods reduces the salivary pH and intensifies the corrosion of brackets and orthodontic wires. This study aimed to compare electro galvanic corrosion of different orthodontic brackets and wires and determine the amount of ions released into acidic artificial saliva. Methods: In this in vitro experimental study, 24 mandibular incisor brackets of 4 different manufacturers (Dentaurum, American Orthodontics, Shinye and ORJ) with stainless steel (SS) or nickel-titanium (Ni-Ti) round wires 0.016 were immersed in acidic artificial saliva for 28 days and their potential difference with the reference electrode was recorded. The amount of released ions was measured in the solution using atomic absorption method. Data were analyzed using two-way ANOVA and repeated measures ANOVA.Results: The mean amount of ions released was not significantly different between groups (p>0.05). The potential difference of Shinye brackets coupled to SS wire was significantly lower than that of other combinations and was negative throughout the study. The potential difference of Dentaurum bracket-NiTi wire, ORJ bracket-NiTi wire, Shinye bracket-SS wire and ORJ bracket-SS wire combinations at the end of experiment was negative as well.Conclusion: The galvanic corrosion of Shinye bracket coupled to SS wire in acidic artificial saliva was greater than that of other bracket-wire combinations. The specimens were not significantly different in terms of the released ions

Galvanic Corrosion of Orthodontic Brackets and Wires in Acidic Artificial Saliva: Part II

Objective: Orthodontic wires should have high resistance against corrosion in the oral environment. Since the effect of pH on corrosion has been well recognized, this study sought to assess and compare the electrochemical corrosion of orthodontic brackets and wires of different brands in   acidic artificial saliva.Methods: This in vitro experimental study was conducted on 24 mandibular central incisor brackets of 4 manufacturers namely Dentaurum, American Orthodontics, Shinye and ORJ. The brackets were immersed in acidic artificial saliva along with stainless steel (SS) or NiTi 0.016 round wires for 28 days. All specimens were weighed before and after the experiment by a digital scale. After the experiment, the specimens were evaluated under a light stereomicroscope and specimens with corrosion were further assessed by scanning electron microscope (SEM) and energy-dispersive X- ray spectroscopy (EDX). Two-way ANOVA was used for statistical analysis.Results: The mean corrosion rate (CR) was -1.80, 0.11, 0.05 and -0.93 mpy for Dentaurum, American Orthodontics, Shinye and ORJ brackets, respectively in combination with NiTi wire; these values were 0.46, -0.71, 0.87 and -0.27 mpy, respectively in combination with SS wires; the differences in this regard were not statistically significant (p>0.05). Micrographs showed high corrosion in ORJ brackets followed by Shinye brackets. EDX showed that the combination of ORJ bracket with SS wire had the highest iron (Fe) content and the highest CR.Conclusion: SS brackets manufactured by Shinye and ORJ companies in combination with SS wires showed higher CR in acidic artificial saliva compared to other bracket/wire combinations

Effects of Processing Methods of Barley Grain and Non-Protein Nitrogen Sources on Rumen Degradability Characteristics, Gas Production and Microbial Protein Synthesis in Afshari Breeding Fattening Lambs

Introduction: Lack of animal feed, especially with development of industrial methods of animal husbandry waste in many parts of the world, has led farmers and researchers to try identifying and using agricultural and livestock waste and new food sources for animal nutrition, including poultry manure and urea is mentioned in the diet of ruminants. Due to the fact that no research has been done on the effect of barley grain processing methods and non-protein nitrogen sources in the diet on rumen degradability, gas production and microbial protein synthesis in sheep, the present study was conducted.Materials and methods: This experiment was conducted in a completely randomized design with seven treatments including a control treatment containing whole barley grain (without milling) and without urea and chicken manure, treatments 2, 3 and 4 containing processing method of milling, filling and pelleting with a certain level of urea, respectively. (1%) And treatments 5, 6 and 7 containing processing methods of milling, filling and pelleting with a certain level of poultry manure (12%) were performed on sheep. Each treatment consisted of 5 fattening lambs at the age of 3 months 24±1 which were kept individually in separate cages for 14 days of acclimatization period and 84 days of fattening period. In the second experiment, rumen degradability of dry matter, crude protein and NDF of experimental diets were measured using a nylon bag method with 3 fistulated male sheep that were fed in the maintenance level. Extent and rate of gas production were done based on Menk and Stingas. The NH3-N concentration was determined following the Broderick and Kang (1980) technique. Purine derivatives and was measured by the method of Chen and Gomes (1995). Rumen fluid was collected for 5 consecutive days in the end of each period and ruminal fermentation parameters containing pH and NH3-N and were determined. Urine of sheep was collected end of each period for 5 days and microbial protein synthesis was estimated by measuring purine base. Data were analyzed using SAS software version 9.9 (54) using GLM procedure.Results and Discussion: The apparent digestibility of dry matter and organic matter were significantly different, and the control treatment (whole barley grain without urea and poultry manure) had the highest apparent digestibility. Digestibility in non-fibrous carbohydrates was significantly different, so that treatment 5 (processing method of milling with poultry manure) had the highest apparent digestibility. Different parameters of degradability of dry matter, crude protein and insoluble fibers in neutral detergent of experimental treatments indicated significant differences between treatments (P<0.05). Barley grain processing with non-protein nitrogen sources caused a significant difference in the fast decomposing part, slow decomposing part and degradable part of dry matter, crude protein and insoluble fibers in the crude protein neutral detergent of experimental treatments. Effective degradability of dry matter, crude protein and insoluble fibers in neutral detergent at 2, 4 and 6% per hour passage rates had a significant difference between experimental treatments. The results showed that there was a significant difference between the experimental treatments in terms of gas production parameters and the amount of gas produced in 96 hours (P<0.05). There was a significant difference between experimental treatments in terms of digestibility of organic matter, amount of metabolizable energy and concentration of short-chain volatile fatty acids. The highest pH was assigned to treatment 7 (6.30) and the lowest pH was assigned to treatment 1 (6.10). Ammonia nitrogen had a significant difference in experimental treatments. The highest ammonia nitrogen was related to treatment 5 (11.45 mg/dL) and the lowest ammonia nitrogen was related to treatment 3 (10.38 mg/dL). The excretion rate of each of the purine derivatives (allantoin, uric acid, xanthine + hypoxanthine) and the total urinary excretion of purine derivatives and the amount of microbial protein synthesized in the rumen were affected by the test diets and the observed difference was significant (P<0.05). There was a significant difference in rumen pH in experimental treatments. The results showed that barley grain processing methods with non-protein nitrogen sources had a significant effect on rumen degradability, gas production, rumen parameters and microbial protein synthesis compared to the control group.Conclusion: In general, the use of urea (1%) and poultry manure (12%) with different methods of barley grain processing without negative effects on rumen degradability, rumen liquid parameters and gas production in terms of microbial protein synthesis can be useful

Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid

This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L−1 sodium chloride, liquid membrane containing 1-octanol with 20% (w/v) tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm. The organic phase immobilized in the pores of a hollow fiber was back-extracted into 24 µL of a solution containing sodium carbonate with pH 11, which was placed inside the lumen of the fiber. Under optimized conditions, the high enrichment factors of 172 and 195 folds, detection limit of 0.007 and 0.009 µg·mL−1 were obtained. The relative standard deviation (RSD) (%) values for intra- and inter-day precisions were calculated at 2.5%–8.2% and 4.1%–10.7%, respectively. The proposed method was successfully applied to the analysis of these metabolites in real urine samples. The results indicated that hollow-fiber liquid-phase microextraction (HF-LPME) based on facilitated pH gradient transport can be used as a sensitive and effective method for the determination of mandelic acid and hippuric acid in urine specimens

Subclinical Hypothyroidism in Pregnancy:Intellectual Development of Offspring

Background: The effects of maternal subclinical hypothyroidism (M-SCH) on the neuropsychological development of the offspring are not clear. We evaluated the intellectual development of children of mothers who had M-SCH during the pregnancy for these children. Methods: Sixty-two children were recruited. After excluding those age 15, 44 were enrolled. The mothers of these children were part of a sub-pool of 90, of 441 hypothyroid women of reproductive age seen in Tehran endocrine clinics between 1991 and 2003 and who were observed during gestation. Mothers were receiving levothyroxine (LT4) before gestation. Mothers of 19 children (control group) had normal serum thyrotropin (TSH) during the pregnancy that produced these children. Mothers of the other 25 children had increased TSH during the comparable pregnancy. Nineteen mothers had M-SCH (case group) and six had overt hypothyroidism. Serum TSH and free T4 (FT4) and urine iodine were measured, and seven cognitive performance and intelligence quotient (IQ) tests were performed. Results: Case children were similar to control children with respect to gender, age, parental education, maternal age at time of pregnancy and at the time of their hypothyroidism, percent mothers having thyroid peroxidase antibodies, LT4 dose of mothers during pregnancy, gestational age at delivery, birth weight, and duration of breast feeding. Maternal TSH (mean – standard deviation) in the case group during their mother’s pregnancies was 11.3 – 5.3 and 1.4 – 1.0mU/L in the controls ( p < 0.001). Serum TSH, FT4 and urinary iodine concentrations were similar in the two groups. Total IQ, performance IQ, and verbal IQ were similar, being 120 – 14, 117 – 12, and 121 – 16, respectively, in the case group and 121 – 11, 120 – 7, and 117 – 15 in the control group. Cognitive performance tests were similar in both groups. No relationships were observed between variables and IQ except for education level of the mother and neonatal weight. Conclusion: IQ level and cognitive performance of children born to LT4-treated hypothyroid mothers is similar in those whose mothers have M-SCH during pregnancy compared with those whose mothers have normal serum TSH concentrations during pregnancy

Chemoradiation therapy of 4T1 cancer cells with methotrexate conjugated platinum nanoparticles under X-Ray irradiation

© 2023 Elsevier B.V.Bovine serum albumin (BSA) coated platinum (Pt) nanoparticles (Pt@BSA NPs) were synthesized, followed by the conjugation of an anticancer drug (MTX) with the aim of chemoradiation therapy. The physical and chemical properties of Pt@BSA-MTX were evaluated by DLS, FESEM, STEM, UV–Vis and XRD. A release study was performed in the presence and absence of the proteinase K enzyme. In terms of morphology, nanoparticles appeared to be monodispersed and spherical. The size of nanoparticles was 7.4 ± 1.4 nm. Release behavior of Pt@BSA-MTX depended significantly on enzyme presence which accelerated and promoted the release of MTX. The improved chemoradiation was demonstrated in vitro using MTT, colony formation and apoptosis assays on mouse breast carcinoma cells (4T1). It was concluded that the combination of a nanoradiosensitizer with a chemotherapeutic agent resulted in superior anticancer activity after X-ray exposure