Objective: To establish a inductively coupled plasma mass spectrometry method for the determination of trace cobalt and tungsten in human urine. Methods: The authors used 1% nitric acid solution as diluent in October-December 2021, the sample dilution factor and internal standard element were optimized by single factor rotation experiment, and the difference between the working curve and the standard curve was compared. Results: The method uses working curve to determine cobalt and tungsten in urine, the linear range of this method was 0.0~10.0 μg/L, the correlation coefficient was 0.999 9, the detection limits respectively were 0.005 μg/L (cobalt) and 0.09 μg/L (tungsten), the recoveries of samples respectively were 87.0%~100.2% (cobalt) and 89.4%~104.8% (tungsten), the relative standard deviations respectively were 0.4%~4.4% (cobalt) and 0.6%~3.8% (tungsten) . Conclusion: A simple and rapid method for determination of cobalt and tungsten in urine has been established. This method has the advantages of simple operation, high sensitivity, low detection limit and good stability. It is suitable for determination of cobalt and tungsten in urine of all kinds of people.
Humans ; Cobalt/analysis* ; Tungsten/analysis* ; Spectrum Analysis ; Nitric Acid ; Mass Spectrometry

The use of pure titanium and titanium alloys have been increased recently in fixed, removable prosthodontics and implant fields as a framework. But when they were used for superstructures of implant of metal framework of removable prosthesis, welding is necessary to reconnect the fracture site to control the casting distortions. To overcome the difficulties in soldering the titanium due to high oxidation property, much effort have been devoted. In this study, some of mechanical properties were compared between pure titanium and Ti-6Al-4V alloy by usingl aser welding, electron beam welding technique and tungsten arc welding. Mechanical properties such as tensile strength, yield strength, elongation and microhardness were measured. And, in order to compare the effect of welding site and surrounding metal tissue according to the welding condition, SEM photographs were taken an element distribution was observed by Wave Dispersion Spectroscopy. Through analyses of the data, following results were obtained; 1. In items such as tensile strength, yield strength and elongation according to the welding techniques of pure titanium, only tungsten arc welded group showed significant lower value than other groups(P<0.05). 2. In items such as tensile strength and yield strength according to the welding techniques of Ti-6Al-4V alloy, control group and tungsten arc welded group showed significant difference among all the groups(P<0.05). 3. Ti-6Al-4V alloy exhibited significantly greater elongation than control group when the laser welding method and electron beam welding method were used, and elongation showed increasing tendency. 4. Pure titanium specimens exhibited increasing tendency of microhardness regardless of the welding technique applied, and especially tungsten arc welded group demonstrated a great increase of microhardness than parent metal. 5. There was no hardness change in laser welded group and electron bean welded group of Ti-6Al-4V ally, but in tungsten arc welded group, hardness changed greatly from parent metal to weld seam. 6. Through the metallographic examination and scanning electron microscopy, laser welding caused central fusion and recristallizations were formed and tungsten arc welding caused localized fusion to 0.3-0.7mm from the surface.
Alloys ; Hardness ; Humans ; Microscopy, Electron, Scanning ; Parents ; Prostheses and Implants ; Prosthodontics ; Spectrum Analysis ; Tensile Strength ; Titanium* ; Tungsten ; Welding*

Routine protein assays are usually affected with various compounds, and we need to use different protein quantification protocol to deal with different interference. In order to simplify the procedure, we developed a new method, in which the components and concentrations of the reagents were modified mainly based on classic Folin-Ciocalteu's reagent for reducing the susceptibility to interfering substances. Standard curves of the new method were established with different levels of bovine serum albumin, and then, we assessed and evaluated the detectable wavelengths and stability. In particular, the tolerability to several interfering substances was analyzed by using cytolysis solutions containing different chemicals. Our data in this study show that the new method could be applied to detecting protein concentrations accurately, even in the presence of surfactants such as 10% sodium dodecyl sulfate (SDS), 2% NP-40, or 1% TrintonX-100, chelators of 25 mmol/L EDTA or 1 mmol/L Ethylene glycol bis (2-aminoethyl) tetraacetic acid (EGTA), reductants of 1 mmol/L Dithiothretol (DTT) orbeta-Mercaptoethanol (ME), or nitrogen-containing compounds of 0.5 mol/L ammonium sulphate or 4 mol/L urea. Taken together, these results indicate that the new approach significantly improves the tolerance to the interfering substances, which could be potentially useful in measuring the contents of proteins interfered with such substances.
Animals ; Edetic Acid ; chemistry ; Egtazic Acid ; chemistry ; Indicators and Reagents ; chemistry ; Molybdenum ; chemistry ; Proteins ; analysis ; Serum Albumin, Bovine ; analysis ; Surface-Active Agents ; chemistry ; Tungsten Compounds ; chemistry