• Journal of Nutrition and Health
• /
• v.22 no.2
• /
• pp.91-101
• /
• 1989

This study was performed to investigate the effects of different dietary magnesium levels on systolic blood pressure and mineral distribution in normotensive and spontaneously hypertensive rats. In experiment 1, Normotensive rats(NTR ; Sprague Dawley, Female) were given diets containing regular magnesium (0.05% Mg ; rMg), marginal magnesium (0.01% Mg ; mMg) or marginal magnesium with stress(0.01% Mg + stress ; mMg + Str). In experiment 2, spontaneously hypertensive rats (SHR ; Kyoto Wistar, Femal) were fed diets containing regular magnesium(0.05% Mg ; rMg) and high magnesium (0.2% Mg ; hMG). The following were found ; 1) NTR treated with marginal magnesium with stress showed significant increase in systolic blood pressure (SBP). Marginal magnesium diet without stress resulted in nonsignificant increase in SBP. Significant in crease of blood pressure showed in NTR treated with marginal magnesium and stress was associated with decreased magnesium and increased calcium content in femur, reticulocyte and plasma. 2) In experiment 2, magnesium supplementation to SHR showed significant attenuation of their systolic blood pressure with increasing age. The attenuation of SBP showed in SHR was associated with increased magnesium, lowered calcium content in cardiac muscle and reticulocyte and decreased plasma sodium and aldosterone level.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.5
• /
• pp.936-942
• /
• 1997

The present study was carried out to investigate the effects of dietary protein and magnesium levels on calcium and magnesium metabolism in male Sprague-Dawley rats. Forty-eight male rats(average weight, 210g) divided into six diet groups; protein 8% and Mg-free diet, protein 8% and Mg 400mg/kg diet, protein 8% and Mg 900mg/kg diet, protein 20% and Mg-free diet, protein 20% nd Mg 400mg/kg diet, and protein 20% and Mg 800mg/kg diet group. After the rats were fed with experimental diets concentration were examined. Kidney weight was significantly higher in protein 8% and Mg-free group compared with other groups. Serum calcium concentration of protein8% group tended to decrease with the increase of the level of magnesium. Serum magnesium concentration in protein 8% and 20% group was lower in Mg-free group than that in other groups(p<0.05) and it also increased as the dietary magnesium level was increased. Urinary calcium and magnesium concentration in Mg-free group were significantly lower than those of other groups.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.30 no.1
• /
• pp.33-39
• /
• 2022

Batch experiments were conducted to find out the effects of various types of magnesium compounds on phosphorus recovery by magnesium ammonium phosphate (MAP) crystallization. The phosphorus recovery from the centrate of anaerobic digested sludge was performed using magnesium chloride, magnesium hydroxide and magnesium oxide under different pH (7.5, 8.0 and 8.5) and Mg/P molar ratio (1.0, 1.5, 2.0, 2.5) conditions. The phosphorus recovery rate increased with increasing pH and Mg/P molar ratio in all magnesium compounds. At pH 7.5, magnesium oxide showed the highest phosphorus recovery rate, followed by magnesium hydroxide and magnesium chloride. However, at pH 8.5, more than 90% of phosphorus recovery rate was obtained in all Mg/p molar ratios. Thus, it is expected that magnesium hydroxide and magnesium oxide are able to replace magnesium chloride as a magnesium source in terms of phosphorus recovery efficiency and cost.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.12 no.3
• /
• pp.212-218
• /
• 1983

The effect of dietary calcium and magnesium on the 3-Hydroxy-3-methyl-glutaryl coenzyme A reductase (E.C. 1.1.1.34) in rabbit's liver microsomal protein was studied for a period of 4 weeks using isocalories and isonitro-genous as a basal diet. The experimental rabbits fed the following basal diets, such as crude protein 68.45%, carbohydrates 13.38%, fats 16.17% and added some sorts of calcium and magnesium, according to experimental plan making. The subject rabbits were divided into 9 feeding groups. The results are summarized as follows. Body weight gains per week of the groups fed magnesium and basal diet showed a little bit increase, but the groups fed calcium and basal diet showed a little bit decrease compare with control group. In case of serum magnesium, control group was 9.5mg% groups fed basal diet and magnesium were 8.27mg% in average, groups fed basal diet and calcium were 4.45mg% in average. In case of serum calcium, control group was 15.3mg%, groups fed basal diet and magnesium were 14.6mg% in average, groups fed basal diet and calcium were 14.1mg% in average. There was no great difference between magnesium fed groups in serum calcium. In serum triglyceride, control group was 82.8mg%, groups fed magnesium and basal diet were 60.3mg% in average, groups fed calcium and basal diet were 69.5mg% in average. The calcium fed groups were higher than the magnesium fed groups in serum triglyceride. In serum cholesterol, control group was 80mg%, groups fed magnesium and basal diet were 64.3mg% in average, groups fed calcium and basal diet were 56.3mg% in average. The calcium fed groups were lower than the magnesium fed groups in serum cholesterol. In case of the 3-Hydroxy-3-methylglutaryl coenzyme A reductase activity, control group was 0.998nmol/min/mg protein, groups fed magnesium and basal diet of HMG-CoA were 0.849nmol/min/mg in average.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.2
• /
• pp.225-228
• /
• 1992

The study was undertaken to determine the effect of various levels of dietary magnesium on the metabolizability of magnesium in laying Tsaiya ducks and Leghorn hens. Twenty-five Tsaiya ducks and 25 Leghorn hens were raised in individual cages. The basal diet was mainly consisted of corn starch and isolated soybean protein. At the beginning of the experiments, birds were fed the basal diet added with 500 mg/kg Mg (1070 mg/kg in total by analysis) for 10 days in order to make the birds adapt to the new diet. Then, they were randomly divided into five treatments with five birds for each treatment and fed the experimental diets containing 690, 1070, 1690, 2150 or 2380 mg/kg Mg for 21 days and during the last five days excreta were collected. The experiment was repeated three times each at the age of 25, 31 and 36 weeks. The metabolizability of magnesium in the diet was determined by the indicator method. The metabolizabilities of magnesium for Tsaiya duck and Leghorn hen were 59.9% and 62.5%, respectively as the diet contained 690 mg/kg magnesium, and were significantly decreased (p<0.05) to 39.7 and 30.7%, respectively when the dietary magnesium content was increased to 2380 mg/kg.

• Journal of Nutrition and Health
• /
• v.31 no.6
• /
• pp.1031-1038
• /
• 1998

The present study was carried out to investigate the effects of magnesium supplement levels and periods on calcium, magnesium, and phosphorus metabolism in male Sprague-Dawley rats given low protein and magnesium deficient diets for 2 weeks. Serum calcium content was significantly lower in the magnesium supplement group than in the magnesium-deficient group, but calcium excretion in urine and feces was significantly increased as magnesium level and period was increased. Increasing the dietary magnesium level and periods raised serum content and excretion of magnesium in urine k feces. Urinary excretion of phosphorus in two week group was significantly lower in the magnesium supplement group than in the magnesium-deficient group. fecal phosphorus excretion in supplement group (Mg 800mg/kg diet) was significantly higher than that of other group. (Korean J Nutrition 31(6) : 1031-1038, 1998)

• Journal of Nutrition and Health
• /
• v.28 no.5
• /
• pp.442-450
• /
• 1995

This study determined plasma glucose, free fatty acid(ffa), epinephrine, norepinephrine, creatine the phosphokinase(CPK), calcium (Ca), magnesium(Mg) and hydroxyproline, Ca and Mg in the heart muscle. Thirty six male Sprague Dawley rats average weighing 110g divided into two diet group : normal Mg group(0.05% Mg), Marginal Mg group(0.005% Mg). After the rats were on experimental diets for 2 weeks, rats for each group were randomly assigned to stress and no stress group and 30 minutes IMMB stress was administered to stress group every day for two weeks. The following were found : 1) Rats fed normal magnesium diet showed decreased plasma glucose and non signficant change in norepinephrine and CPK with IMMB stress, while magnesium deficient rats showed elevated plasma glucose, norepinephrine and CPK with stress. 2) Myocardial hydroxyproline and plasma epinephrine were not significantly different among groups. 3) In the rats fed adequate magnesium, stress increased plasma magnesium while rats on marginal magnesium diet did not show significant change with stress. 4) Plasma and myocardial calcium were increased in rats fed marginal Mg diet, but did not show any significant difference with stress.

• Korean Journal of Soil Science and Fertilizer
• /
• v.36 no.4
• /
• pp.218-224
• /
• 2003

Magnesium hydroxide, which recently registered as a Mg fertilizer, is greatly different from magnesium sulfate in its solubility and effect on soil pH. In this study, the effects of magnesium hydroxide and magnesium sulfate on growth of chinese cabbage were compared at the application rate of $300kg\;MgO\;ha^{-1}$ in a Gyeongsan clay loam soil. Although magnesium hydroxide was effective in increasing number of leaf and fresh weight, overall effects of magnesium hydroxide and magnesium sulfate on the growth of chinese cabbage were not significantly different ($p{\leq}0.05$). Comparing the two magnesium fertilizer treatments, magnesium content of chinese cabbage was relatively higher in the magnesium sulfate treatment in the early stage of growth, but it was higher in the magnesium hydroxide treatment at harvest. Contents of Ca, P, and K in chinese cabbage were relatively higher in the magnesium hydroxide treatment than those in magnesium sulfate treatment. But, the differences in nutrient uptakes by chinese cabbage between the treatments were not significant ($p{\leq}0.05$). Therefore, magnesium hydroxide is expected to be used with nearly the same effects on crops as magnesium sulfate at the same application rate of Mg. Soil pH in the treatment of magnesium sulfate was lower than that of control treatment, but magnesium hydroxide could increase pH. Magnesium hydroxide can be used preferentially in acid and/or sandy soils, where magnesium sulfate can induce further soil acidification and leaching loss of Mg is often a severe problem.

• Environmental Engineering Research
• /
• v.19 no.1
• /
• pp.101-105
• /
• 2014

Three magnesium compounds, $MgO_2$, MgO, and $Mg(OH)_2$, which are supposed to supply oxygen continuously, were applied onto contaminated bay sediment and its ecology in order to activate the local microbial flora. Those compounds were found to reduce chemical oxygen demand (COD), total nitrogen (T-N), and total phosphorus (T-P). Magnesium oxide, in particular, reduced COD by 30% and T-N and T-P considerably. All compounds also suppressed the release of pollutants in the order $MgO_2$, MgO, and $Mg(OH)_2$. Analysis of microbial flora showed that the microbial group treated by $MgO_2$ and $Mg(OH)_2$ was predictably stable; meanwhile, that treated by MgO increased the number of species, but decreased the total number of microorganisms.

• Transactions of Materials Processing
• /
• v.23 no.8
• /
• pp.495-500
• /
• 2014

Magnesium alloys are currently expected to be widely used for weight reduction of cars and as high efficient materials in the automotive and electronics industries. Although the specific strength of magnesium is excellent, it cannot be easily formed at room temperature due to its HCP structure. However in order to improve the formability of magnesium, it is necessary to investigate its formability in the warm temperature range. In the current study, the aim was to add to the magnesium property database so that the mass production of a magnesium car body can be accomplished. Warm tensile tests were conducted and the forming limit diagram was determined to confirm formability characteristics of magnesium AZ31B alloy sheet. In addition the bending formability and the magnesium damping capacity were evaluated for AZ31B and compared to SPRC440E which is a sheet steel used for car bodies.