• Clinical and Experimental Pediatrics
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• v.63 no.2
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• pp.48-51
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• 2020

Background: The etiopathogenesis of late preterm (LPT) birth is undetermined. Placental histopathology, which reflects an adverse intrauterine environment and is reportedly associated with preterm labor and neonatal morbidities, has not been studied in LPT infants. Purpose: We investigated placental pathological lesion as markers of an adverse intrauterine environment during LPT labor. Methods: This retrospective case-control study compared placental histopathological and clinical variables between LPT and term neonates. Placental variables included chorioamnionitis, funisitis, hemorrhage, abruption, infarction, calcification, and syncytial knots. Maternal variables included age, substance abuse, pregnancyassociated diabetes mellitus and hypertension, duration of rupture of membrane, antibiotic use, and magnesium sulfate, whereas, those of neonates included gestational age, birth weight, race, sex, and Apgar scores. Standard statistical proedures were applied to analyze the data. Results: Chorioamnionitis (50% vs. 17.8%, P<0.001) and funisitis (20% vs. 4.4%, P=0.002) were more common in term infants. Placental infarction rate was insignificantly higher in LPT infants (25.6% vs. 14.3%, P=0.08). The mothers in the LPT group were older (30.4 years vs. 28.1 years, P=0.05; odds ratio [OR], 1.06; 95% confidence interval [CI], 0.998-1.12, P=0.056) and more often suffered from hypertension (28.9 vs. 12.9 %, P=0.02), and received magnesium sulfate (48.9 vs. 20%, P< 0.001; OR, 2.86; 95% CI, 1.12-7.29, P<0.05). Duration of rupture of membrane was higher in term infants (13.6 hours vs. 9.1 hours, P<0.001). Chorioamnionitis (OR, 0.33; 95% CI, 0.13-0.79; P<0.05) was associated with a lower risk of LPT delivery. Conclusion: Placental infection is not a risk factor for LPT births. There is a nonsignificant predominance of vascular anomalies in LPT placentas. Higher maternal age, magnesium sulfate therapy, and maternal hypertension are clinical risk factors for LPT labor.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.3
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• pp.147-154
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• 2020

Background: Single inferior alveolar nerve block is ineffective in achieving adequate pulpal anesthesia in 30-80% of patients due to anatomical variations, local tissue pH, central sensitization, and several factors. Various supplementary techniques and combination of adjuvants with lignocaine are used to overcome these failures. Magnesium sulfate (MgSO₄), one such adjuvant, acts at the N-methyl-D-aspartate glutamate receptor resulting in effective anesthesia. The aim of this prospective, randomized, double-blind, clinical controlled trial was to evaluate the onset, anesthetic efficacy, duration and post-operative analgesia of 2% lignocaine with and without the addition of MgSO₄ in patients with symptomatic irreversible pulpitis and apical periodontitis. Methods: Fourty-two patients were randomly divided into three groups: 2% lignocaine (group 1) and 2% lignocaine with MgSO₄ (75 mg) and (150 mg) in groups 2 and 3, respectively. Pre-operative vitals and Heft Parker-Visual Analogue Scale (HP-VAS) pain scores were recorded. The onset of anesthesia, anesthetic efficacy, and duration of anesthesia were evaluated post administration of the local anesthetic solution. The post-operative analgesia was examined at intervals of 2, 6, 12, 24, and 48 h. Results: Administration of 150 mg MgSO₄ hastens the onset of anesthesia (1.29 min) and produces better anesthetic efficacy (3.29 HP-VAS) compared to group 2 (2.07 min and 9.14 HP-VAS) and group 1 (3.29 min and 35.79 HP-VAS), respectively. The duration of anesthesia was significantly higher in group 3 (247.07 min) compared to that of groups 2 and 1 (190 min and 110.21 min) with P < 0.05. Conclusion: Combining 75 mg or 150 mg of MgSO₄ with lignocaine is more effective than 2% lignocaine and 75 mg of MgSO₄ is adequate for endodontic procedures.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.551-564
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• 2003

Statement of problem : Magnesium oxide may increase pH of alginate, and supply magnesium ions to the polymerization reaction of alginate. Purpose : This study was designed to evaluate the influence of incorporation of magnesium oxide to alginate composition. Material and Method : Seven kinds of experimental alginates were prepared and used for the experiments. Components with unchanging concentrations were sodium alginate 15%, calcium sulfate 14%, sodium phosphate 2%, and zinc fluoride 3%. Contents of magnesium oxide were varied as 0%, 1%, 2%, 3%, 4%, 5%, 6%. Diatomaceous earth were added to each experimental groups as balance to be 100%. Control group was a MgO 0% group. Working time, setting time, elastic recovery strain in compression, compressive strength and tear resistance were measured were measured. Sample size for each groups were 10. Arithmetic means were used as each groups representative values. Regression test between MgO contents and results, Duncan's multiple range test, and One-way ANOVA test were done between groups at level of 0.05. Results : 1 Magnesium oxide made the working time and setting time as longer(p<0.0001). 2 Magnesium oxide did not alter the elastic recovery(p>0.05). 3. Magnesium oxide contents between 2% and 4% exhibited the lowest strain in compression on alginates(p<0.0001). 4. Magnesium oxide made the compressive strength and the tear resistance stronger(p<0.0001). Conclusion : These results mean that setting time of alginate maybe controlled and that mechanical properties maybe improved by the incorporation of magnesium oxide into alginate, without any reduction of elasticity.

• Computers and Concrete
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• v.33 no.1
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• pp.1-11
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• 2024

Aggressive environmental conditions, and especially the acidic effects of sulfate ion penetration, have reduced the lifetime of concrete structures in some areas, especially coastal and marine areas. In this research, at first, samples made of type II and V cement were kept in a solution of magnesium sulfate (MgSO₄) for a period of 90 and 180 days, the change of appearance. Field Emission Scanning Electron Microscopy (FE-SEM) and X-Ray Diffraction (XRD), were used to analyze the microstructure and the complex mineral composition of the concrete after exposure to corrosive environments. Then solving the differential equation governing the sulfate ion penetration, which is based on the second Fick law, it has been tried to determine the concentration of sulfate ions inside the concrete. In the following, an attempt has been made to improve the prediction of sulfate ion concentration in concrete by using Crank's penetration equation. At the same time, the coefficient in the Crank's solution have been optimized by using the Particle Swarm Optimization (PSO algorithm). The comparison between the results shows that the values obtained from Crank's relation are closer to the experimental results than the equation obtained from Fick's second law and shows a more accurate prediction.

• International Journal of Concrete Structures and Materials
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• v.9 no.2
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• pp.145-158
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• 2015

The consequence of sulfate attack on geopolymer concrete, made from an alkali activated natural pozzolan (AANP) has been studied in this paper. Changes in the compressive strength, expansion and capillary water absorption of specimens have been investigated combined with phases determination by means of X-ray diffraction. At the end of present investigation which was to evaluate the performance of natural alumina silica based geopolymer concrete in sodium and magnesium sulfate solution, the loss of compressive strength and percentage of expansion of AANP concrete was recorded up to 19.4 % and 0.074, respectively.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.839-852
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• 1997

It has been submitted that different ion solutions containing sulfate induce crystal growth and might substitute conventional acid etching for pretreatment of enamel in orthodontic bonding(${\AA}rtun$ et al., Am. J. Orthod. 85, 333, 1984). This investigation was designed to evaluate the relevance of crystal growth on the enamel surface as an alternative to conventional acid etching in direct bonding of orthodontic brackets. Annexing Li2SO4, MgSO4, K2SO4 respectively in the solution with $25\%$ polyacrylic md 0.3M sulfuric acids were employed to enhance the crystal growth. Human bicuspids were treated with various parameters as combinations of crystal growth and glass ionomer cement, crystal growth and orthodontic resin, acid etching and orthodontic resin for an investigative purpose. Crystal growth solution containing MgSO4 showed the highest shear bond strength(15.6MPa) within the groups of bonding brackets with glass ionomer cement(p<0.01). Bonding with glass ionomer cement on the surface of crystal growth demonstrated higher shear bond strength than with orthodontic resin(p<0.001). Bonding with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 was not different shear bond strength statistically from bonding with orthodontic resin on the acid-etched surface. It suggests that bonding brackets with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 is a potential alternative to bonding with resin on the acid etched sufrace.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.75-79
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• 2012

Objective : The study examined the difference in the incidence of symptomatic cerebral vasospasm with magnesium supplementation in aneurysmal subarachnoid hemorrhage (SAH) in a Korean population. Methods : This retrospective analysis was performed in 157 patients diagnosed with aneurysmal SAH from January 2007 to December 2011 at a single center. Seventy patients (44.6%) received a combination treatment of nimodipine with magnesium and 87 patients (55.4%) received only nimodipine. A matched case-control study using propensity scores was conducted and 41 subjects were selected from each group. A dosage of 64 mmol/day of magnesium was administrated. Results : The infusion of magnesium did not reduce the incidence of symptomatic cerebral vasospasm (n=7, 17.1%, p=0.29) compared with simple nimodipine injection (n=11, 26.8%). The ratios of good clinical outcome (modified Rankin scale 0-2) at 6 months were similar, being 78% in the combination treatment group and 80.5% in the nimodipine only group (p=0.79). The proportions of delayed cerebral infarction was not significantly lower in patients with combination treatment (n=2, 4.9% vs. n=3, 7.3%; p=0.64). There was no difference in the serum magnesium concentrations between the patients with symptomatic vasospasm and without vasospasm who had magnesium supplementation. No major complications associated with intravenous magnesium infusion were observed. Conclusion : Magnesium supplementation (64 mmol/day) may not be beneficial for the reduction of the incidence of symptomatic cerebral vasospasm in patients with aneurysmal SAH.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.18-23
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• 2011

The electrokinetic transport characteristics of salts were investigated using nitrate and sulfate accumulated saline greenhouse soil. Within 8 days, 95% of nitrate was removed from the soil, while sulfate removal was 19% for 8 days. The low removal of sulfate came from adsorption reaction on the soil particles or organic matter and precipitation with calcium. Divalent cations such as calcium and magnesium were transported toward cathode via electromigration, and most monovalent cation such as potassium was removed. The pattern of residual electrical conductivity was similar with that of sulfate. Based on the results, electrokinetic technique is effective to restore nitrate-accumulated saline soil, but is not effective to restore sulfate-accumulated soil.

• Journal of Korean Society of Forest Science
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• v.37 no.1
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• pp.35-40
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• 1978

The uptake ratio of supplying $P^{32}$ labelled double superphosphate and the hastening efficiency of the uptake by addition of magnesium sulfate to the fertilizer were studied on the ${\times}Populus $ albaglandulosa planted with 0/1 cutting in 1975. The results are summerized as follows. 1. Average 13% of supplying double superphosphate was absorbed into ${\times}Populus$ albaglandulosa planted on the reddish heavy clay soil in Institute of Forest Genetics. 2. The accumulation of absorbed magnesium was more amount in leaf than in stem. 3. The uptake ratio of supplying double superphosphate was able to increase up to 16%~33% by the addition of magnesium sulfate to the fertilizer. 4. It might be possible to increase the tree growth following the acceleration of photosynthesis due to the increasing amount of magnesium known to be a component of chlorophyll in leaf as well as to hasten the efficiency of uptake of phosphorus by the addition of magnesium to double superphosphate.

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.112-112
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• 2023