OBJECTIVEThis study evaluated the wear of an antagonist and friction and wear properties of dental zirconia ceramic that was subjected to microwave and conventional sintering methods.

METHODSTen specimens were fabricated from Lava brand zirconia and randomly assigned to microwave and conventional sintering groups. A profile tester for surface roughness was used to measure roughness of the specimens. Wear test was performed, and steatite ceramic was used as antagonist. Friction coefficient curves were recorded, and wear volume were calculated. Finally, optical microscope was used to observe the surface morphology of zirconia and steatite ceramics. Field emission scanning electron microscopy was used to observe the microstructure of zirconia.

RESULTSWear volumes of microwave and conventionally sintered zirconia were (6.940±1.382)×10⁻², (7.952±1.815) ×10⁻² mm³, respectively. Moreover, wear volumes of antagonist after sintering by the considered methods were (14.189±4.745)×10⁻², (15.813±3.481)×10⁻² mm³, correspondingly. Statistically significant difference was not observed in the wear resistance of zirconia and wear volume of steatite ceramic upon exposure to two kinds of sintering methods. Optical microscopy showed that ploughed surfaces were apparent in zirconia. The wear surface of steatite ceramic against had craze, accompanied by plough. Scanning electron microscopy showed that zirconia was sintered compactly when subjected to both conventional sintering and microwave methods, whereas grains of zirconia sintered by microwave alone were smaller and more uniform.

CONCLUSIONSTwo kinds of sintering methods are successfully used to produce dental zirconia ceramics with similar friction and wear properties.
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Ceramics ; Dental Porcelain ; Friction ; Humans ; Magnesium Oxide ; Materials Testing ; Microscopy, Electron, Scanning ; Microwaves ; Silicon Dioxide ; Surface Properties ; Zirconium

OBJECTIVETo observe the effect of magnesium sulfate, Nifedipine Tablet (NT) combined Salvia Injection (SI) on endothelin-1 (ET-1), nitric oxide (NO), thromboxane A2(TXA2), prostacyclin I2(PG2), and hemorheology of preeclampsia patients.

METHODSTotally 704 preeclampsia patients were randomly assigned to the treatment group and the control group, 352 cases in each group. All patients were treated with magnesium sulfate combined NT (on the first day: slow intravenous injection of magnesium sulfate 5 g + intravenous dripping of magnesium sulfate injection 10 g + oral administration of NT 30 mg; on the second and third day, intravenous dripping of magnesium sulfate injection 10 g + oral administration of NT 30 mg), while those in the treatment group were dripped with SI additionally at 20 mL per day for 3 consecutive days. Before and after treatment plasma levels of endothelin-1 (ET-1), nitric oxide (NO), TXA2, PGi2, and hemorheology indicators [such as high blood viscosity (HBV), low blood viscosity (LBV), plasma viscosity (PV), erythrocyte rigidity index (ERI), fibrinogen (FIB)] of two groups were detected.

RESULTSCompared with the same group before treatment, serum levels of ET-1, TXA2, HBV, LBV, PV, ERI, and FIB decreased in the two groups after treatment (P <0. 05), but levels of NO and PG2 increased (P <0. 05). Compared with the control group in the same period, levels of ET-1, TXA2, HBV, LBV, PV, ERI, and FIB decreased in the treatment group after treatment (P <0. 05), but levels of NO and PGI2 increased (P <0. 05).

CONCLUSIONMagnesium sulfate, NT combined SI could effectively regulate the balance of ET-1/NO and TXA2/PGI2, and improve hemorheology of preeclampsia patients.

Drug Therapy, Combination ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Endothelin-1 ; metabolism ; Epoprostenol ; metabolism ; Female ; Hemorheology ; Humans ; Injections ; Magnesium Sulfate ; administration & dosage ; pharmacology ; therapeutic use ; Nifedipine ; administration & dosage ; pharmacology ; therapeutic use ; Nitric Oxide ; metabolism ; Pre-Eclampsia ; drug therapy ; Pregnancy ; Salvia ; Tablets ; Thromboxane A2 ; metabolism

In this report, we present a pediatric case of severe symptomatic hypermagnesemia resulting from the use of magnesium oxide as a laxative in a child undergoing continuous cyclic peritoneal dialysis for end-stage renal disease. The patient showed abnormal electrocardiography (ECG) findings, such as tall T waves, a widened QRS complex, and irregular conduction, which were initially misdiagnosed as hyperkalemia; later, the correct diagnosis of hypermagnesemia was obtained. Emergent hemodialysis successfully returned the serum magnesium concentration to normal without complications. When abnormal ECG changes are detected in patients with renal failure, hypermagnesemia should be considered.
Child ; Electrocardiography ; Humans ; Hyperkalemia ; Kidney Failure, Chronic ; Magnesium ; Magnesium Oxide ; Peritoneal Dialysis ; Renal Dialysis ; Renal Insufficiency

Gitelman syndrome is a rare autosomal recessive hereditary salt-losing tubulopathy, that manifests as hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria. It is caused by mutations in the solute carrier family 12(sodium/chloride transporters), member 3 (SLC12A3) gene encoding the thiazide-sensitive sodium chloride cotransporter channel (NCCT) in the distal convoluted tubule of the kidney. It is associated with muscle weakness, cramps, tetany, vomiting, diarrhea, abdominal pain, and growth retardation. The incidence of growth retardation, the exact cause of which is unknown, is lower than that of Bartter syndrome. Herein, we discuss the case of an overweight 12.9-year-old girl of short stature presenting with hypokalemic metabolic alkalosis. The patient, on the basis of detection of a heterozygous mutation in the SLC12A3 gene and poor growth hormone (GH) responses in two provocative tests, was diagnosed with Gitelman syndrome combined with complete GH deficiency. GH treatment accompanied by magnesium oxide and potassium replacement was associated with a good clinical response.
Abdominal Pain ; Alkalosis ; Bartter Syndrome ; Diarrhea ; Gitelman Syndrome ; Growth Hormone ; Humans ; Incidence ; Kidney ; Magnesium Oxide ; Muscle Cramp ; Muscle Weakness ; Overweight ; Potassium ; Sodium Chloride Symporters ; Tetany ; Vomiting

The aim of this study was to compare the compositions and cytotoxicity of white ProRoot MTA (white mineral trioxide aggregate) and 3 kinds of Portland cements. The elements, simple oxides and phase compositions of white MTA (WMTA), gray Portland cement (GPC), white Portland cement (WPC) and fast setting cement (FSC) were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD). Agar diffusion test was carried out to evaluate the cytotoxicity of WMTA and 3 kinds of Portland cements. The results showed that WMTA and WPC contained far less magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) than GPC and FSC. FSC contained far more aluminum oxide (Al2O3) than WMTA, GPC, and WPC. WMTA, GPC, WPC and FSC were composed of main phases, such as tricalcicium silicate (3CaO.SiO2), dicalcium silicate (2CaO.SiO2), tricalcium aluminate (3CaO.Al2O3), and tetracalcium aluminoferrite (4CaO.Al2O3.Fe2O3). The significance of the differences in cellular response between WMTA, GPC, WPC and FSC was statistically analyzed by Kruskal-Wallis Exact test with Bonferroni's correction. The result showed no statistically significant difference (p > 0.05). WMTA, GPC, WPC and FSC showed similar compositions. However there were notable differences in the content of minor elements, such as aluminum (Al), magnesium, iron, manganese, and zinc. These differences might influence the physical properties of cements.
Agar ; Aluminum ; Aluminum Oxide ; Calcium Compounds ; Diffusion ; Glutamates ; Guanine ; Humans ; Iron ; Magnesium ; Manganese ; Oxides ; Plasma ; Silicates ; Spectrometry, X-Ray Emission ; Spectrum Analysis ; Zinc ; Pemetrexed

Mg2Ni0.8Cr0.2-x wt.% CoO/Al2O3 (x=0.5, 1, 2 and 3) composites were prepared by mechanically milling sintered Mg2Ni0.8Cr0.2 alloy and CoO/Al2O3 compound for 45 h. The addition of CoO/Al2O3 compound resulted in the good kinetics properties of hydriding/dehydriding reaction of the composites. The composite with 1.0 wt.% CoO/Al2O3 catalyst could reach the maximum hydrogen absorption capacity (2.9 wt.%) within 5 min at 393 K under H2 pressure of 4 MPa, and can desorb rapidly at 493 K. The decomposition and synthesis of hydrogen molecule on Mg2Ni0.8Cr0.2 alloy surface was promoted by addition of CoO/Al2O3 catalyst. In addition, the formation of metallic Ni particles, strain and defects during the ball milling process also resulted in the improved hydrogenation performance of Mg2Ni-based alloys.
Absorption ; Aluminum Oxide ; analysis ; chemistry ; Hot Temperature ; Hydrogen ; analysis ; chemistry ; Kinetics ; Magnesium Compounds ; analysis ; chemistry ; Manufactured Materials ; analysis ; Materials Testing ; Molecular Conformation ; Nitrogen Compounds ; analysis ; chemistry ; Pressure ; Temperature

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.
Alginates* ; Calcium Sulfate ; Compressive Strength ; Diatomaceous Earth ; Elasticity ; Fluorides ; Hydrogen-Ion Concentration ; Ions ; Magnesium Oxide* ; Magnesium* ; Polymerization ; Polymers ; Sample Size ; Sodium ; Tears ; Zinc

AIMTo study the effects of sodium magnesium fructose diphosphate (SMFD) on free calcium concentration and nitric oxide synthase activity of ischemic synaptosome, so as to explore the protective mechanisms of SMFD on cerebral ischemia.

METHODSThe synaptosomes from normal rat brain were prepared by phase partition and cultured with oxygen-glucose deprivation to establish ischemic synaptosome model. The intrasynaptosomal free calcium concentration and nitric oxide synthase activity were detected separately after the synaptosomes were co-incubated with SMFD (1.3 mmol.L-1) or fructose-1, 6-diphosphate (FDP, 4.0 mmol.L-1) for 60 min.

RESULTSSMFD decreased the free calcium concentration and reduced the activity of nitric oxide synthase (NOS) of ischemic synaptosomes. Its effects were more powerful than those of FDP.

CONCLUSIONSMFD may protect neurons from ischemic injury by preventing intracellular Ca2+ overload and inhibiting the activity of nitric oxide synthase.

Animals ; Brain Ischemia ; enzymology ; metabolism ; Calcium ; metabolism ; Chelating Agents ; pharmacology ; Fructosediphosphates ; pharmacology ; Magnesium ; chemistry ; Male ; Nitric Oxide Synthase ; drug effects ; metabolism ; Rats ; Rats, Wistar ; Sodium ; chemistry ; Synaptosomes ; metabolism

Angiotensins ; analysis ; Animals ; Animals, Newborn ; Biomarkers ; analysis ; Endothelin-1 ; analysis ; Hypertension, Pulmonary ; drug therapy ; metabolism ; physiopathology ; Lung ; chemistry ; pathology ; Magnesium Sulfate ; pharmacology ; Nitric Oxide Synthase ; analysis ; Nitric Oxide Synthase Type II ; Swine ; Vasomotor System ; chemistry

BACKGROUND/AIMS: Polyethylene glycol (PEG) electrolyte lavage solution is now commonly used for peroral colonic preparation. However, the need to ingest a large volume reduces patient acceptance and may limit compliance, thereby resulting in improper preparation. This study was designed to assess whether adding of magnesium oxide or cisapride to PEG solution decreased the volume of PEG solution required without compromising the quality of the preparation. METHODS: One hundred thirty seven patients undergoing outpatient colonoscopy were randomly chosen to receive one of three preparations (Group A: 4 L PEG; Group B: 2 L PEG plus cisapride 20 mg; Group C: 2 L PEG plus magnesium oxide 2 g). Endoscopist was blinded as to the method of preparation and scored the degree of colonic preparation (1 to 4). RESULTS: Mean scores of preparation in group A, B, and C were 2.85, 2.69, and 2.20, respectively (p=0.001). There were significant differences of the degree of preparation between group A and group C, between group B and group C, but not between group A and group B. CONCLUSIONS: Two liters of PEG plus cisapride induced equally effective colonic preparation compared to four liter PEG solution. This results show that the addition of cisapride to PEG solution can reduce volume of PEG solution during colonoscopy preparation.
Cisapride* ; Colon ; Colonoscopy* ; Compliance ; Humans ; Magnesium Oxide ; Outpatients ; Polyethylene Glycols ; Therapeutic Irrigation*