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Objective@#To apply the semi-quantitative risk assessment model in the Technical Guidelines for Occupational Health Risk Assessment of Chemical Hazardous Factors in the Workplace to assess the occupational health risk of electroplating enterprises and explore its applicable conditions and characteristics.@*Methods@#Three electroplating enterprises were selected as the research objects. Occupational hygiene survey and hazard factor detection were conducted on the spot. Three semi-quantitative risk assessment methods were used to assess the risk, and the evaluation results were compared.@*Results@#The consistency between the contact index method and the comprehensive index method was strong. The weighted Kappa value was 0.946 and the P value was less than 0.001, but the consistency between the contact ratio method, the contact index method and the comprehensive index method was poor. The weighted Kappa value was 0.345 and 0.391, and the P value was 0.009 and 0.004, respectively. When the contact concentration is less than 50% OELs, the evaluation results of the contact ratio method are lower than those of the exponential method and the comprehensive exponential method. The consistency of the three methods was the highest when the contact concentration (>50%) and (<OELs). When the contact concentration >OELs, the results of the contact ratio method are higher than those of the index method and the comprehensive index method.@*Conclusion@#Contact ratio method is suitable for occupational health risk assessment under the condition of incomplete occupational health information and for enterprise managers to identify key control points of health risk through self-assessment; Contact index method is suitable for hazard risk assessment of occupational hazards without sampling test conditions or OELs, and pre-assessment of occupational hazards of construction projects without access to analogical test data. The index method is suitable for occupational health risk assessment with available testing data and complete occupational health information.
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OBJECTIVE: To study the combined effect of noise and hydrogen cyanide on noise-induced hearing loss( NIHL)in a metal electroplating enterprise. METHODS: The judgment sampling method was used to select 663 workers in a largescale metal electroplating enterprise as the study subjects. Among them,186 workers exposed to noise alone were designated as noise group; 138 workers exposed to hydrogen cyanide alone were designated as hydrogen cyanide group; and161 workers exposed to noise and hydrogen cyanide were designated as combined effect group,and 178 workers without exposure from occupational disease risk factors were designated as control group. Questionnaires survey and pure tone audiometry were used for analyzing the effects of combined noise and hydrogen cyanide exposure on NIHL. RESULTS: The hearing loss detection rate of the study subjects was 40. 4%. The hearing loss detection rates in the control group,noise group,hydrogen cyanide group,and combined effect group were 17. 4%,47. 8%,32. 6% and 64. 0%,respectively. The detection rate of hearing loss in the control group was lower than that in the other three groups( P < 0. 008). The NIHL detection rates in the combined effect group and the noise group were higher than that in the hydrogen cyanide group( P <0. 008). The hearing loss detection rate of the combined effect group was higher than that of the noise group and the hydrogen cyanide group( P < 0. 008). Ordinal multi-categorical logistic regression model results showed that after adjusting confounding factors such as age,length of service,gender,marital status,smoking,alcohol drinking,we found hydrogen cyanide exposure,noise exposure,and combined exposure to hydrogen cyanide and noise had effects on workers' hearing(P < 0. 05). The risk of hearing loss in workers exposed to noise and hydrogen cyanide was higher than that of workers exposed to noise alone or hydrogen cyanide alone. CONCLUSION: There is a combined effect of noise and hydrogen cyanide in this metal electroplating enterprise,which can increase the risk of NIHL in workers.
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Effluent samples from an electroplating industry located at Madurai, India were collected and analysed for chosen physico-chemical parameters. Among the heavy metals tested, zinc exhibited highest level with 739 ppm with a pH of 4.83. The bacterial strain isolated from the effluent contaminated site was identified as Escherichia coli and it was subjected to 15, 20 and 25% of effluent in minimal broth for 20 days. Optical density and pH changes were recorded daily and the levels of chromium, nickel and zinc were analysed after ten and twenty days of treatment. Significant reduction in the level of zinc was observed and the results are discussed.
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Introdução: a cidade de Limeira (SP) se caracteriza por ser um polo de empresas do ramo de joias folheadas e bijuterias, sendo a maior parte da mão de obra composta por mulheres. Objetivo: verificar as morbidades referidas por mulheres expostas ao cianeto no setor de bijuterias e joias folheadas na cidade de Limeira em 2007. Metodologia: estudo transversal realizado com 383 trabalhadoras, comparando-se um grupo de 191 mulheres trabalhadoras em galvanoplastias consideradas qualitativamente expostas ao cianeto com um grupo de 192 mulheres não expostas ao cianeto. Foi aplicado o Índice de Capacidade para o Trabalho, o Questionário de Tolerância de Fagerstrõm e um questionário sociodemográfico e ocupacional. Resultados: O grupo considerado exposto ao cianeto apresentou: menor média de tempo de trabalho no cargo (p = 0,008), maior proporção que trabalha com produtos químicos (p < 0,001), que usa Equipamento de Proteção Individual (p < 0,001), que recebe equipamento das empresas em que trabalham (p < 0,001), menor quantidade de morbidades referidas (p = 0,042), mas maior prevalência de bronquite crônica (p = 0,027), sinusite crônica (p = 0,022) e disfunções da tireoide (p = 0,022). Conclusões: os resultados apontam para a necessidade de pesquisas de coorte que analisem a associação entre os agravos apresentados e a exposição ao cianeto.
Introduction: The city of Limeira in São Paulo, Brazil, is characterized by a cluster of companies producing jewelry, plated jewelry, and fashion jewelry, with most of the laborforce composed of women. Objective: The purpose of this research was to assess the health conditions of workers from gold plated and costume jewelry manufacturers in Limeira, in 2007. Methodology: Transversal study involving 383 women, comparing a group of 191 workers of electroplating sites considered exposed to cyanide to a group of 192 non-exposed. Work Index Capacity, Fagerstrõm Scale of Tolerance, and a socio-demographic and occupational questionnaire wereapplied. Results: The exposed group presented shorter average of time working in the company (p = 0.008), higher proportion of workers dealing with chemicals (p<0.001), wearing Personal Protective Equipment (PPE) (p <0.001), and receiving PPE provided by the companies where they worked (p <0.001). The group exposed to cyanide also presented lower proportion in reported morbidity (p = 0.042), but higher prevalence of chronic bronchitis (p = 0.027), chronic sinusitis (p = 0.022), and thyroid disorders (p = 0.022). Conclusion: The results indicate the needfor cohort studies to examine the association between the reported diseases and cyanide exposure.
Subject(s)
Argentum Cyanatum/adverse effects , Electroplating , Occupational Health , Occupational Risks , Occupational GroupsABSTRACT
The gill which participate in many important functions in fish, such as respiration, osmoregulation and excretion. Electroplating industrial effluent nickel induced hyperplasia, multiple telangiectases (aneurysms), desquamation of the epithelial cells, complete fusion of secondary gill lamellae and congestion of blood sinuses were the significant histopathological lesions observed in the gill of Mystus cavasius.
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A number of surface modification techniques using immobilization of biofunctional molecules of Titanium (Ti) for dental implants as well as surface properties of Ti and Ti alloys have been developed. The method using passive surface oxide film on titanium takes advantage of the fact that the surface film on Ti consists mainly of amorphous or low-crystalline and non-stoichiometric TiO2. In another method, the reconstruction of passive films, calcium phosphate naturally forms on Ti and its alloys, which is characteristic of Ti. A third method uses the surface active hydroxyl group. The oxide surface immediately reacts with water molecules and hydroxyl groups are formed. The hydroxyl groups dissociate in aqueous solutions and show acidic and basic properties. Several additional methods are also possible, including surface modification techniques, immobilization of poly(ethylene glycol), and immobilization of biomolecules such as bone morphogenetic protein, peptide, collagen, hydrogel, and gelatin.
Subject(s)
Alloys , Bone Morphogenetic Proteins , Calcium , Calcium Phosphates , Collagen , Dental Implants , Electroplating , Gelatin , Hydrogels , Imidazoles , Immobilization , Nitro Compounds , Surface Properties , TitaniumABSTRACT
The purpose of this study was to evaluate electroless plating as a method of increasing the diameter of an orthodontic wire in comparison with eletroplating. After pretreatment plating of the 0.016 inch stainless steel orthodontic wire, electroless plating was performed at 90 degrees C until the diameter of the wire was increased to 0.018 inch. During the process of electroless plating, the diameter of the wire was measured every 5 minutes to examine the increasing ratio of the wire' diameter per time unit. And to examine the uniformity, the diameter at 3 points on the electroless-plated orthodontic wire was measured. An X-ray diffraction test for analyzing the nature of the plated metal and a 3-point bending test for analyzing the physical property were performed. The electroless-plated wire group showed a increased tendency for stiffness, yield strength, and ultimate strength than the electroplated wire group. And there was a statistically significant difference between the two groups for stiffness and ultimate strength. In the electroless-plated wire group, the increasing ratio of the diameter was 0.00461 +/-.00003 mm/5 min (0.00092 mm/min). In the electroplated wire group, it was 0.00821 +/-.00015 mm/min. The results of the uniformity test showed a tendency for uniformity in both the plating methods. The results of this study suggest that electroless plating of the wire is closer to the ready-made wire than electroplating wire in terms of the physical property. However, the length of plating time needs further consideration for the clinical application of electroless plating.
Subject(s)
Electroplating , Orthodontic Wires , Stainless Steel , X-Ray DiffractionABSTRACT
The purpose of this study was to examine the cytotoxicity of orthodontic wire which had an increased diameter through electroplating, and to evaluate its possible clinical applications. First, nickel plating was carried out on the commercially available stainless steel wire using an electroplating technique. For the comparison of the electroplated wire with ready made stainless steel wire and titanium or copper, each wire was incubated for 72 hours in a medium. The release of the metal ion was measured using ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrophotometer). Balb/c 3T3 mouse fibroblast was put on a microplate and placed in an incubated medium of 75%, 50%, and 20% dilation. An MTT analysis was used to compare with the medium only. The change in absorbency value of each wire group and the difference of absorbency value according to the change of dilution was measured. The results of ICP-AES analysis showed that great amount nickel ion was isolated from electroplated orthodontic wires and great amount copper ion was isolated from copper. The results of the MTT analysis showed that there was no difference in the absorbency value of titanium at any dilution. However, the electroplated wires (p < 0.001), the stainless steel wires (p < 0.05) and the copper (p < 0.001) were statistically significantly lower than those of medium only at all dilutions. Assessment as per ISO 10993, part 5, showed that electroplated wire was alloted to "moderate cytotoxic", the titanium and stainless steel wire were "non-cytotoxic". The results of this study indicate that the electroplated orthodontic wires need additional efforts to decrease cytotoxicity for their clinical applications.
Subject(s)
Animals , Mice , Copper , Electroplating , Fibroblasts , Nickel , Orthodontic Wires , Plasma , Stainless Steel , TitaniumABSTRACT
The purpose of this study was to evaluate the possibile clinical application of electroplating to increase diameter of an orthodontic wire, through examining the change of physical properties. The diameter of stainless steel orthodontic wire was increased from 0.016 inch to 0.018 inch by electroplating in a bath of nickel sulfate 100g/L, nickel chloride 60g/L, boric acid 30g/L, and sodium chloride 50g/L, under the conditions of 1.7V, 25~29degrees C, and 3.1~3.3pH. During the electroplating, the rate of diameter increase was measured every minute. To investigate uniformity, the diameter was measured at three different locations of each wire specimen after electroplating. An X-ray diffraction test was performed to analyze the nature of the electroplated metal. Following heat treatment to improve adhesion between the wire and electroplated metal, a three-point bending test was conducted to compare stiffness, yield strength, and ultimate strength among four wire groups; 0.016 inch, electroplated 016, electroplated and heat-treated 016, and 0.018 inch wires. Through the comparison of each wire group, following results were obtained. 1. In the load-deflection graph, the curve of the electroplated group was placed between that of the 0.016 inch group and the 0.018 inch group, and the curve was closer to the 0.018 inch group by heat treatment. 2. In the electroplated and heat-treated 016 wire group, the values of stiffness, yield strength and ultimate strength showed higher tendency than in the original 0.016 inch group. Stiffness and ultimate strength showed statistically significant differences between two groups. 3. Stiffness, yield strength, and ultimate strength of electroplated wire presented lower values than those of 0.018 inch wire group. 4. Stiffness, yield strength, and ultimate strength of electroplated and heat-treated wire showed higher tendency than those of electroplated wire group, and ultimate strength showed statistically significant difference between two groups. 5. After electroplating, the difference in diameter between the three locations was within 0.1~0.3% variation, and showed no statistical significance.
Subject(s)
Baths , Electroplating , Hot Temperature , Nickel , Orthodontic Wires , Sodium Chloride , Stainless Steel , X-Ray DiffractionABSTRACT
The purpose of this study was to evaluate clinical applications of electroplating method through investigation of the physical properties of orthodontic rectangular wires according to varying their cross section. For the study, it was accomplished to electroplate the 0.016-inched orthodontic rectangular stainless steel wire. The cross section of stainless steel orthodontic rectangular wire increased from 0.016 x 0.016 inch to 0.017 x 0.017 inch by electroplating. The wire was heat treated to improve an adhesion between the wire and electroplated metal. A three-point bending test and torsion test were conducted in order to compare physical properties among three wire groups; 0.016 x 0.016 wires (group 016), electroplated 0.016 x 0.016 wires (group 016P) and 0.017 x 0.017 wires (group 017). Through the investigations of each wire group, following results were obtained. 1. At three-point bending test, the group 016P showed higher tendency in the degree of stiffness, yield strength and ultimate tensile strength than the group 016. Stiffness and ultimate tensile strength showed statistically significant differences between two groups at three-point bending test (p<0.05). 2. Stiffness, yield strength, and ultimate tensile strength of the group 016P showed lower tendency than those of the group 017. Stiffness showed statistically significant differences between two groups at three-point bending test (p<0.05). 3. Torque/twist rate, yield torsional moment, and ultimate torsional moment of the group 016P showed higher tendency than those of the group 016. All measurements showed statistically significant differences between two groups after torsion test (p<0.05). 4. Torque/twist rate, yield torsional moment, and ultimate torsional moment of the group 016P showed lower tendency than those of the group 017. Yield torsional moment, and ultimate torsional moment showed statistically significant differences between two groups after torsion test (p<0.05).
Subject(s)
Electroplating , Hot Temperature , Stainless Steel , Tensile StrengthABSTRACT
The screw loosening is one of the complications that happen frequently in dental implant prostheses. The purpose of this study was to evaluate the changes of reverse/loosening (opening) torque of the screw according to the surface modifications by sandblasting and 24K gold electroplating as well as to determine the possibility of the clinical use of a washer in dental implant. The reverse torque of 4 experimental conditions(control, sandblasted, use of washers, electroplasted) was measured by digital torque gauge (Model MGT50Z, Mark-10 Corp., 458 West John Street Hicksville, NY 11801 USA). Electronic torque controller (Nobel Biocare DEA 020) was used in fastening the gold screws into abutment replicas. Mixed Linear Model Analysis method was used for statistical analysis. To examine the changes of screw thread surface, microphotographs were taken by Olympus PME-3 metallurgic microscope (Olympus Optical Co. Ltd., Tokyo, Japan). Within the limitations of this study, the following results were drawn: 1. The surface modifications of the gold screws and the use of a washer have significantly affected the reverse torque value compared to the control group (p<0.01). 2. Sandblasting and electroplating treatments demonstrated significantly higher reverse torque val-ue than that of control group. 3. The use of a washer may be one of the useful clinical methods that prevent the screw loosening. However, further studies are necessary for the material selection and design of the washer.