Objective: To explore the occupational hazards caused by three kinds of welding operations, and to provide data support for individual protection. Methods: In October 2020, the welding fumes, metal elements and welding arc generated by three welding operations of argon gas shielded welding (JS80 welding wire) , manual welding (ZS60A welding rod) and carbon dioxide shielded welding (907A flux cored wire) were collected and measured in the welding laboratory. The samples were analyze and compare in the laboratory, and the differences of the occupational hazard factors of the three welding operations were judged. Results: The concentration of welding fume produced by carbon dioxide shielded welding, manual welding (ZS60A electrode) , and argon gas shielded welding (JS80 welding wires) were 6.80 mg/m(3), 6.17 mg/m(3), and 3.13 mg/m(3), respectively. The effective irradiance of the welding arc outside the welding mask from high to low is manual welding (ZS60A electrode) , carbon dioxide shielded welding (907A flux-cored welding wire) , and argon shielded welding (JS80 welding wire) , respectively 1 010.7, 740.9, 589.5 μW/cm(2). The long-wave ultraviolet UVA intensity generated by argon shielded welding (JS80 welding wire) is the largest, which is 1 500 μW/cm(2). The content of Mn in the three welding operations is the highest, and JS80 welding wire has the highest Mn content of 128493.2 mg/kg. 907A flux cored wire has the highest Ti content, which is 24355.5mg/kg. The electrode ZS60A has the highest Cu content, which is 24422.12 mg/kg. Conclusion: The intensity of occupational hazards is different in the three kinds of welding operations, so the methods of personal protective equipment, field exposure assessment and health monitoring should be more targeted.
Air Pollutants, Occupational/analysis* ; Argon/analysis* ; Carbon Dioxide/analysis* ; Gases/analysis* ; Occupational Exposure/analysis* ; Welding/methods*

PURPOSE: The purpose of this study was to investigate the electrochemical characteristics of nanotubular Ti-25Nb-xZr ternary alloys for dental implant materials. MATERIALS AND METHODS: Ti-25Nb-xZr alloys with different Zr contents (0, 3, 7, and 15 wt.%) were manufactured using commercially pure titanium (CP-Ti), niobium (Nb), and zirconium (Zr) (99.95 wt.% purity). The alloys were prepared by arc melting in argon (Ar) atmosphere. The Ti-25Nb-xZr alloys were homogenized in Ar atmosphere at 1,000℃ for 12 hours followed by quenching into ice water. The microstructure of the Ti-25Nb-xZr alloys was examined by a field emission scanning electron microscope. The phases in the alloys were identified by an X-ray diffractometer. The chemical composition of the nanotube-formed surfaces was determined by energy-dispersive X-ray spectroscopy. Selforganized TiO₂ was prepared by electrochemical oxidation of the samples in a 1.0 M H₃PO₄+0.8 wt.% NaF electrolyte. The anodization potential was 30 V and time was 1 hour by DC supplier. Surface wettability was evaluated for both the metallographically polished and nanotube-formed surfaces using a contact-angle goniometer. The corrosion properties of the specimens were investigated using a 0.9 wt.% aqueous solution of NaCl at 36℃±5℃ using a potentiodynamic polarization test. RESULT: Needle-like structure of Ti-25Nb-xZr alloys was transform to equiaxed structure as Zr content increased. Nanotube formed on Ti-25Nb-xZr alloys show two sizes of nanotube structure. The diameters of the large tubes decreased and small tubes increased as Zr content increased. The lower contact angles for nanotube formed Ti-25NbxZr alloys surfaces showed compare to non-nanotube formed surface. The corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface showed longer the passive regions compared to non-treatment surface. CONCLUSION: It is confirmed that corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface has longer passive region compared to without treatment surface.
Alloys* ; Argon ; Atmosphere ; Corrosion ; Dental Implants* ; Freezing ; Ice ; Nanotubes ; Niobium ; Spectrum Analysis ; Titanium ; Water ; Wettability ; Zirconium

OBJECTIVES: The purpose of this study was to determine a separation method for each arsenic metabolite in urine by using a high performance liquid chromatography (HPLC)- inductively coupled plasma-mass spectrometer (ICP-MS). METHODS: Separation of the arsenic metabolites was conducted in urine by using a polymeric anion-exchange (Hamilton PRP X-100, 4.6 mm x 150 mm, 5 mum) column on Agilent Technologies 1260 Infinity LC system coupled to Agilent Technologies 7700 series ICP/MS equipment using argon as the plasma gas. RESULTS: All five important arsenic metabolites in urine were separated within 16 minutes in the order of arsenobetaine, arsenite, dimethylarsinate, monomethylarsonate and arsenate with detection limits ranging from 0.15 to 0.27 mug/L (40 muL injection). We used GEQUAS No. 52, the German external quality assessment scheme and standard reference material 2669, National Institute of Standard and Technology, to validate our analyses. CONCLUSIONS: The method for separation of arsenic metabolites in urine was established by using HPLC-ICP-MS. This method contributes to the evaluation of arsenic exposure, health effect assessment and other bio-monitoring studies for arsenic exposure in South Korea.
Argon ; Arsenic* ; Cacodylic Acid ; Chromatography, Liquid ; Environmental Monitoring ; Korea ; Limit of Detection ; Plasma ; Polymers ; Spectrum Analysis*

OBJECTIVETo evaluate the safety and efficacy of intraoperative argon/helium cryosurgery in surgical resection of advanced hepatic carcinoma.

METHODSEighty-six surgical patients with advanced hepatic carcinoma were enrolled in this study, including 14 undergoing argon cryosurgery for tumor removal and 72 receiving cryosurgery in addition to surgical tumor reduction. Portal vein or hepatic arterial pump placement was performed in 15 patients for chemotherapy.

RESULTSNo death occurred in the operation or during the postoperative hospitalization period in these patients. Improvement of the clinical symptoms was observed in 66 cases (76.74%) and 43 (78.18%) patients showed significantly decreased blood AFP levels after the surgeries. Postoperative CT demonstrated obviously reduced tumor size in 58 cases (67.44%). Of the 70 patients available for the follow-up, 28 survived with a survival rate of 40%. The 0.5-, 1-, 3 and 5-year survival rates were 44/48 (91.67%), 35/48 (72.92%), 28/48 (58.33%), and 20/48(41.67%) in the patients with primary hepatic carcinoma (PHC), respectively, as compared with those of 21/22 (95.45%), 18/22 (81.82%), 13/22 (50.09%), and 8/22 (36.36%) in patients with metastasis hepatic carcinoma (MHC). The 1-, 3- and 5-year survival rates of the patients undergoing surgical tumor resection and cryosurgery were 65/72 (90.27%), 47/60 (78.33%) and 24/58 (41.38%), respectively, significantly higher than the rates of 10/14 (71.43%), 8/12 (66.67%) and 4/12 (33.33%) in the patients receiving cryosurgery only (P<0.05).

CONCLUSIONSArgon cryosurgery offers an effective and safe option for management of advanced hepatic carcinoma, and its combination with other therapeutic approaches may achieve better clinical effects.

Adult ; Aged ; Argon ; Carcinoma, Hepatocellular ; surgery ; Combined Modality Therapy ; Cryosurgery ; Female ; Helium ; Humans ; Liver Neoplasms ; secondary ; surgery ; Male ; Middle Aged ; Survival Analysis