Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.517
Filtrar
1.
Environ Res ; 216(Pt 3): 114736, 2023 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-36343713

RESUMEN

In welding, there is a potential risk due to metal-oxide nanoparticles (MONPs) exposure of workers. To investigate this possibility, the diameter and number particles concentration of MONPs were evaluated in different biological matrices and in personal air samples collected from 18 stainless-steel welders and 15 unexposed administrative employees engaged in two Italian mechanical engineering Companies. Exhaled breath condensate (EBC) and urine were sampled at pre-shift on 1st day and post-shift on 5th day of the workweek, while plasma and inhalable particulate matter (IPM) at post-shift on 5th day and analysed using the Single Particle Mass Spectrometry (SP-ICP-MS) technique to assess possible exposure to Cr2O3, Mn3O4 and NiO nanoparticles (NPs) in welders. The NPs in IPM at both Companies presented a multi-oxide composition consisting of Cr2O3 (median, 871,574 particles/m3; 70 nm), Mn3O4 (median, 713,481 particles/m3; 92 nm) and NiO (median, 369,324 particles/m3; 55 nm). The EBC of welders at both Companies showed Cr2O3 NPs median concentration significantly higher at post-shift (64,645 particles/mL; 55 nm) than at pre-shift (15,836 particles/mL; 58 nm). Significantly lower Cr2O3 NPs median concentration and size (7762 particles/mL; 44 nm) were observed in plasma compared to EBC of welders. At one Company, NiO NPs median concentration in EBC (22,000 particles/mL; 65 nm) and plasma (8248 particles/mL; 37 nm) were detected only at post-shift. No particles of Cr2O3, Mn3O4 and NiO were detected in urine of welders at both Companies. The combined analyses of biological matrices and air samples were a valid approach to investigate both internal and external exposure of welding workers to MONPs. Overall, results may inform suitable risk assessment and management procedures in welding operations.


Asunto(s)
Contaminantes Ocupacionales del Aire , Nanopartículas , Exposición Profesional , Soldadura , Humanos , Acero Inoxidable/análisis , Obreros Metalúrgicos , Monitoreo Biológico , Exposición Profesional/análisis , Óxidos/análisis , Soldadura/métodos , Material Particulado/análisis , Compuestos Orgánicos/análisis , Contaminantes Ocupacionales del Aire/análisis , Monitoreo del Ambiente
2.
Sci Rep ; 12(1): 18637, 2022 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-36329178

RESUMEN

Tandem welding is extensively used for welding large structures, such as ships and plants, for increased welding speed and volume. Seam tracking is essential because of a large amount of thermal deformation. However, in tandem welding, arc interference causes current and voltage to vary non-uniformly, leading to difficulties in seam tracking. Therefore, in this study, an optimal signal was identified for seam tracking in tandem welding and evaluated. To select the seam-tracking signal, an algorithm was developed that separates the welding signal into peak, average, and base. Based on the collected data, regression and signal-to-noise ratio analyses were performed to identify a suitable seam-tracking signal. To trace the welding line based on the selected signal, the welding signal was checked by weaving on the V-groove specimen. As a result, the current area difference of the welding signal generated between the left and right parts of the center of the V-groove could be calculated. An algorithm and equipment for seam tracking were constructed using the area difference of the welding current. Finally, the seam tracking system was verified by conducting an actual test using the equipment to which the algorithm was applied.


Asunto(s)
Soldadura , Ocupaciones
3.
Biomolecules ; 12(11)2022 Nov 13.
Artículo en Inglés | MEDLINE | ID: mdl-36421697

RESUMEN

High-frequency electric field welding-induced tissue fusion has been explored as an advanced surgical method for intestinal anastomoses; however, intrinsic mechanisms remain unclear. The aim of this study was to investigate microcosmic changes of collagen within the fusion area, with various parameters. Ex vivo small intestine was fused with mucosa-mucosa. Four levels of compressive pressure (100 kPa, 150 kPa, 200 kPa, 250 kPa) were applied for 10 s in order to fuse the colons under a power level of 140 W. Then, collagen fibers of the fusion area were examined by fibrillar collagen alignment and TEM. Three levels of power (90 W, 110 W, 140 W) and three levels of time (5 s, 10 s, 20 s) were applied in order to fuse colons at 250 kPa, and then collagen within the fusion area was examined by Raman spectroscopy. Fibrillar collagen alignment analysis showed that with the increase in compression pressure, alignment of the collagen in the fusion area gradually increased, and the arrangement of collagen fibers tended to be consistent, which was conducive to the adhesion of collagen fibers. TEM showed that pressure changed the distribution and morphology of collagen fibers. Raman spectroscopy showed that increased power and time within a certain range contributed to collagen cross linking. Peak positions of amide I band and amide III band changed. These results suggested that higher power and a longer amount of time resulted in a decrease in non-reducible cross links and an increase in reducible cross links. Compression pressure, power, and time can affect the state of collagen, but the mechanisms are different. Compressive pressure affected the state of collagen by changing its orientation; power and time denatured collagen by increasing temperature and improved the reducible cross linking of collagen to promote tissue fusion.


Asunto(s)
Soldadura , Colágeno/química , Colágenos Fibrilares , Intestino Delgado , Amidas
4.
Sensors (Basel) ; 22(21)2022 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-36366111

RESUMEN

Electrode misalignment, produced by mechanical fatigue or bad adjustments of the welding gun, leads to an increase in expulsions, deformations and quality problems of the welding joints. Different studies have focused on evaluations of the influence of a misalignment of the electrodes and the final quality of the weld nugget. However, few studies have focused on determining a misalignment of the electrodes to avoid problems caused by this defect, especially in industrial environments. In this paper, a method for performing the condition monitoring of electrode alignment degradation was developed following previous research, which has shown the relationship between the misalignment of short-circuited electrodes and the magnetic field generated by them. This method was carried out by means of a device capable of measuring the magnetic field. Finally, an integral system for the detection of misalignments in real production lines is presented. This system set behavior thresholds based on the experimentation, allowing the condition monitoring of the alignment after each welding cycle.


Asunto(s)
Soldadura , Soldadura/métodos , Electrodos
5.
Sensors (Basel) ; 22(21)2022 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-36366244

RESUMEN

Real-time tracking welding with the assistance of structured light vision enhances the intelligence of robotic welding, which significantly shortens teaching time and guarantees accuracy for user-customized product welding. However, the robustness of most image processing algorithms is deficient during welding practice, and the security regime for tracking welding is not considered in most trajectory recognition and control algorithms. For these two problems, an adaptive feature extraction algorithm was proposed, which can accurately extract the seam center from the continuous, discontinuous or fluctuating laser stripes identified and located by the CNN model, while the prior model can quickly remove a large amount of noise and interference except the stripes, greatly improving the extraction accuracy and processing speed of the algorithm. Additionally, the embedded Pauta criterion was used to segmentally process the center point data stream and to cyclically eliminate outliers and further ensure the accuracy of the welding reference point. Experimental results showed that under the guarantee of the above-mentioned seam center point extraction and correction algorithms, the tracking average error was 0.1 mm, and even if abnormal trajectory points existed, they did not cause welding torch shaking, system interruption or other accidents.


Asunto(s)
Soldadura , Soldadura/métodos , Algoritmos , Procesamiento de Imagen Asistido por Computador/métodos , Rayos Láser , Tecnología
6.
Neurotoxicology ; 93: 324-336, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36309163

RESUMEN

Motor synergies, i.e., neural mechanisms that organize multiple motor elements to ensure stability of actions, are affected by several neurological condition. Asymptomatic welders showed impaired synergy controlling the stability of multi-finger action compared to non-welders and this impairment was associated with microstructural damage in the globus pallidus. We further explored the effect of welding-related metal exposure on multi-finger synergy and extended our investigation to posture-stabilizing synergy during a standing task. Occupational, MRI, and performance-stabilizing synergies during multi-finger accurate force production and load releasing while standing were obtained from 29 welders and 19 age- and sex-matched controls. R2* and R1 relaxation rate values were used to estimate brain iron and manganese content, respectively, and diffusion tensor imaging was used to reflect brain microstructural integrity. Associations of brain MRI (caudate, putamen, globus pallidus, and red nucleus), and motor synergy were explored by group status. The results revealed that welders had higher R2* values in the caudate (p = 0.03), putamen (p = 0.01), and red nucleus (p = 0.08, trend) than controls. No group effect was revealed on multi-finger synergy index during steady-state phase of action (ΔVZss). Compared to controls, welders exhibited lower ΔVZss (-0.106 ± 0.084 vs. 0.160 ± 0.092, p = 0.04) and variance that did not affect the performance variable (VUCM, 0.022 ± 0.003 vs. 0.038 ± 0.007, p = 0.03) in the load releasing, postural task. The postural synergy index, ΔVZss, was associated negatively with higher R2* in the red nucleus in welders (r = -0.44, p = 0.03), but not in controls. These results suggest that the synergy index in the load releasing during a standing task may reflect welding-related neurotoxicity in workers with chronic metals exposure. This finding may have important clinical and occupational health implications.


Asunto(s)
Contaminantes Ocupacionales del Aire , Exposición Profesional , Soldadura , Humanos , Imagen de Difusión Tensora , Esfuerzo Físico , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Manganeso/toxicidad , Metales , Contaminantes Ocupacionales del Aire/toxicidad
7.
Sensors (Basel) ; 22(19)2022 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-36236232

RESUMEN

Butt welding is extensively applied in long-distance oil and gas pipelines, and it is of great significance to conduct non-destructive ultrasonic testing of girth welds in order to avoid leakage and safety accidents during pipeline production and operation. In view of the limitations of large transducer size, single fixed beam angle, low detection resolution and high cost of conventional ultrasonic inspection technologies, a 16-channel piezoelectric micro ultrasonic transducer (PMUT) array probe was developed through theoretical analysis and structural optimization design. After the probe impedance characterization, the experimental results show that the theoretical model can effectively guide the design of the ultrasonic transducer array, offering the maximum operating frequency deviation of less than 5%. The ultrasonic echo performance tests indicate that the average -6 dB bandwidth of the PMUT array probe can be up to 77.9%. In addition, the fabricated PMUT array probe has been used to successfully detect five common internal defects in pipeline girth welds. Due to the multiple micro array elements, flexible handling of each element, large bandwidth and high resolution of defect detection, the designed PMUT array probe can provide a good application potential in structural health monitoring and medical ultrasound imaging fields.


Asunto(s)
Ultrasonido , Soldadura , Diseño de Equipo , Transductores , Ultrasonografía/métodos
8.
Front Public Health ; 10: 937774, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36249234

RESUMEN

Introduction: Welding fumes (WF) are a complex mixture of gas and particles. Action of occupational exposure to WF on cardiovascular system has been recently studied as for noise. Research question: The main objectives of our study are therefore to evaluate the impact of exposure to WF, noise, and combined WF and noise on autonomic nervous system as assessed by heart rate variability (HRV). Methods: The study groups were 16 welders and eight airport workers (as a control group). All the participants underwent ambulatory electrocardiogram, personal WF, and noise exposure monitoring, respectively, with dust track and calibrated noise dosimeter during workday. Atmospheric environmental assessments at workplaces have been also performed. HRV parameters were summarized for all the workday and hourly. Correlation tests were used to examine relation between HRV parameters and levels of noise exposure in the two population. Analysis of covariance (ANCOVA) was used for mean of each HRV parameters. Results: For HRV parameters, we found significant higher levels for mean range of high frequency (HF), standard deviation of normal-to-normal R-R interval (SDNN), and root mean square of successive heartbeat interval difference (RMSSD) in welders which suggested an imbalance between sympathetic and parasympathetic nervous system in this population. For relation between noise and HRV parameters, we noted that levels of low frequency (LF), HF, and SDNN were significantly correlated with mean noise levels for welders (respectively, r = 0.62, r = 0.357, r = 0.48), not in control group. Using ANCOVA, we found that working as a welder significantly increases mean of HF (p = 0.01) and RMSSD (p = 0.02) and decreases in LF/HF (p = 0.008). Indeed, the interaction between exposure to WF and mean noise levels for HF (p = 0.005), LF/HF (p = 0.01), and RMSSD (p = 0.007) was significant. Conclusion: This study shows an impact of WF and noise on ANS balance. One hypothesis is WF exposure could increase sensibility to noise exposure on autonomic nervous system or there is a synergic effect.


Asunto(s)
Exposición Profesional , Soldadura , Aeropuertos , Mezclas Complejas/farmacología , Polvo , Frecuencia Cardíaca/fisiología , Humanos , Obreros Metalúrgicos , Exposición Profesional/efectos adversos
9.
ACS Appl Mater Interfaces ; 14(41): 47025-47035, 2022 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-36214770

RESUMEN

The vast majority of traditional vulcanized rubber products are insoluble and infusible, which is difficult to reprocess and biodegrade, resulting in black pollution. In addition, although most rubber materials based on covalent adaptive networks (CANs) can achieve structural reconstruction, the lack of traditional vulcanization system leads to a decline in strength. In this study, biobased vanillin derivatives (PV) were synthesized to cross-link the commercially available 1,2-polybutadiene rubber precursor to construct imine-based CANs, thereby fabricating a resource-renewable, recyclable, and degradable high-performance rubber material. Due to the rigid tripod structure of the PV, the tensile strength of the material can achieve as high as 16.24 MPa, ranking among the best in the field of recyclable polybutadiene-based materials. Benefiting from the dynamic imine unit, the "dynamic covalent bridge" can be re-established to repair the damaged network and endow the material with excellent weldability. And, shape memory faculty of the material was proved and depicted. Moreover, this material displayed excellent antibacterial property originates from the introduced Schiff-base structure. By mixing with graphene, the application of action sensors can also be achieved.


Asunto(s)
Grafito , Soldadura , Goma/química , Antibacterianos/farmacología , Iminas
10.
Front Public Health ; 10: 990547, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36091502

RESUMEN

Background: Welding fumes are a risk factor for welder pneumoconiosis. However, there is a lack of population information on the occurrence of welding fume-induced lung cancer, and little is known about the welding fume pathogenesis. Methods: Welding fume and metal ion concentrations were assessed in a vehicle factory in Wuhan. A Cox regression model estimated lung-related disease risk in workers by independent and combined factors. Results: Workers' exposures were divided into four grades; the highest exposure was among the welders in the maintenance workshop, the highest Mn and Fe exposure was 4 grades, and the highest Cr exposure was 3 grades. Subgroup analysis found that the risk of lung-related disease was 2.17 (95% CI: 1.31-3.57, p < 0.05) in welders compared with non-welders, and the risk of pulmonary disease in male welders was 2.24 (95% CI: 1.34-3.73, p < 0.05) compared to non-welders. Smoking welders had a 2.44 (95% CI: 1.32-4.51, p < 0.01) higher incidence of lung-related diseases than non-welders. Total years of work as an independent protective factor for lung-related disease risk was 0.72 (95% CI: 0.66-0.78, p < 0.01). As an independent risk factor, high-high and high-low exposure had a 5.39 (95% CI: 2.52-11.52, p < 0.001) and 2.17 (95% CI: 1.07-4.41, p < 0.05) higher risk for lung-related diseases, respectively. Conclusions: High welding fume exposure is a significant risk factor for lung-related disease in workers.


Asunto(s)
Enfermedades Pulmonares , Exposición Profesional , Soldadura , Humanos , Pulmón/patología , Enfermedades Pulmonares/epidemiología , Enfermedades Pulmonares/etiología , Enfermedades Pulmonares/patología , Masculino , Exposición Profesional/efectos adversos , Modelos de Riesgos Proporcionales
11.
Dent Med Probl ; 59(3): 333-341, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36098486

RESUMEN

BACKGROUND: Delayed loading in the rehabilitation of edentulous patients with an implant-supported prosthesis implies a longer treatment time. It requires additional surgery to uncover the submerged implants, and this may increase patients' discomfort and morbidity. OBJECTIVES: The immediate loading-based technique described in this article involves creating a metal framework by intraorally welding the implants pair by pair, using specific wing abutments. The aim of the study was to investigate the implant-prosthetic success and complication rates of this technique when used to rehabilitate totally edentulous patients. MATERIAL AND METHODS: The clinical records of totally edentulous patients were retrospectively evaluated. The prosthetic success rate as well as technical and biological complications were analyzed. Furthermore, the implant survival and success rates were assessed by measuring marginal bone loss (MBL) at the implant, prosthesis and patient levels. RESULTS: The records of 37 patients (284 implants and 43 prostheses) were included in the study. At the last follow-up (45.5 ±33.6 months), the prosthetic success rate was 100%. Mucositis affected 4 implants (1.4%), while peri-implantitis affected 4 implants (1.4%). Meanwhile, 7 implants (2.5%) showed a lack of early osseointegration. According to the criteria of Albrektsson et al., 271 implants (95.4%) were successful. The average MBL at the implant, prosthesis and patient levels was 0.26 ±0.42 mm, 0.26 ±0.19 mm and 0.26 ±0.18 mm, respectively. CONCLUSIONS: The technique described in this article seems to be a viable approach to the rehabilitation of totally edentulous patients through immediate loading. However, these results should be confirmed by appropriately designed prospective and comparative clinical studies.


Asunto(s)
Implantes Dentales , Arcada Edéntula , Boca Edéntula , Soldadura , Prótesis Dental de Soporte Implantado , Humanos , Arcada Edéntula/rehabilitación , Arcada Edéntula/cirugía , Estudios Prospectivos , Estudios Retrospectivos
12.
PLoS One ; 17(9): e0273788, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36174072

RESUMEN

Educational virtual environments (EVEs) are defined by their features of immersion (degree of sensory engagement) and fidelity (degree of realism). Increasingly, EVEs are being used for career development and training purposes, which we refer to as career-oriented EVEs. However, little research has examined the effects of immersion and fidelity on career-related outcomes, like self-efficacy and interests, and the learning dynamics that may influence these outcomes. We address these research needs across two studies using an inductive approach. Study 1 compares welding career exploration in EVEs to traditional career exploration and finds that individuals using EVEs report more positive career self-efficacy. Study 2 examines the influence of social learning dynamics, or how individuals learn from each other through behavioral modeling, on performance and career-related self-efficacy and interest. Groups were assigned to use either a high or low immersion and fidelity EVE. Findings indicate strong social learning dynamics in both EVEs, but the effects were stronger for groups using the higher immersion and fidelity EVE. Specifically, groups converged on two performance measures, and the performance of individuals who were situated as behavioral models significantly predicted the performance of other group members. Performance at the individual level, in turn, predicted career self-efficacy and interest for men but not women, and only for those using the higher immersion and fidelity EVE. Based on these findings, we conclude with practical recommendations for and implications of implementing career-oriented EVEs for career exploration and skills training.


Asunto(s)
Aprendizaje Social , Soldadura , Humanos , Masculino , Autoeficacia
13.
Artículo en Chino | MEDLINE | ID: mdl-36052587

RESUMEN

Objective: To explore the changes of γ-GCS mRNA expression and GSH-PX in serum of workers exposed to manganese in order to provide scientific basis for early diagnosis of manganese poisoning. Methods: In June 2017, a total of 180 workers from a motorcycle manufacturer were selected by stratified random sampling, including 115 welders as the exposure group and 65 administrative office workers as the Control Group, the exposure group was divided into high exposure group (43 persons) and low exposure group (72 persons) according to whether the exposure group exceeded the standard limit. The levels of γ-gcs Mrna expression and GSH-Px activity in serum were determined by Occupational Health Survey, and the differences of γ-gcs Mrna expression and GSH-Px activity among different groups were analyzed. Results: Compared with the control group, the serum GSH-Px activity was lower and the serum γ-GCS mRNA expression level was higher in the exposed group (F=370.52, 275.95, P<0.01) . Compared with the control group, there was significant difference in γ-GCS mRNA expression level and GSH-Px activity (F=0.475、1.06, P<0.01; F=48.53、111.70, P<0.01) . The concentrations of manganese in air, welding dust and urine were positively correlated with the level of γ-GCS mRNA (r=0.71, 0.50, 0.31, P<0.01) The serum GSH-Px activity was negatively correlated with the concentrations of manganese in air, welding dust and urine (r=-0.80, -0.52, -0.30, P< 0.01) , There was no correlation between Serum γ-GSH-Px activity and age and years of exposure (P>0.05) . Conclusion: Serum γ-GCS mRNA expression level and GSH-Px activity level can be used as early biomarkers of manganese poisoning. The concentrations of manganese in workplace air, welding dust and urine manganese in workers are the influencing factors.


Asunto(s)
Contaminantes Ocupacionales del Aire , Intoxicación por Manganeso , Exposición Profesional , Soldadura , Polvo , Humanos , Iones , Manganeso , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , ARN Mensajero/genética
14.
Asian Pac J Cancer Prev ; 23(8): 2743-2748, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-36037129

RESUMEN

INTRODUCTION: The aim of this study was to investigate exposure to dust, and metal fumes, changes in pulmonary function indices among industrial workers to estimate the carcinogenic and non-carcinogenic risk of exposure to occupational metal fume.

Methods: This cross-sectional study was performed on 98 workers exposed to metal fumes. Air sampling was performed according to the NIOSH 0500 method and was analyzed by gravimetry and metal levels were analyzed by atomic absorption spectrometry. Spirometric results for 2010-2016 were collected. Carcinogenic and non-carcinogenic risk assessments were performed according to the US Environmental Protection Agency guidelines. Data were analyzed by SPSS 20 software. RESULTS: The mean occupational exposure of the subjects to workplace dust and iron fumes was 15.95 ± 6.65 mg/m3 and 13.18 ± 3.06 mg/m3 respectively. During these 6 years, the FVC (P=0.04), PEFR (P=0.04), and FEV1 (P=0.03) indices decreased significantly among welders, but there was no significant difference between FEV1/ FVC indexes. Also, the mean of FEV1 and PEFR decreased significantly amongst casting workers, but FVC and FEV1/ FVC had no significant difference. Multivariate regression showed that in both jobs, BMI and work history were related to pulmonary function indices. The mean total excess ifetime carcinogenic risk (ELCR) of hexavalent chromium in the study population was 0.708 per 1000 people and the mean non-carcinogenic risk of hexavalent chromium was HQ = 19.62. CONCLUSIONS: The results showed that exposure to metal fumes in casting and welding jobs reduces pulmonary function indices. Although the average occupational exposure to hexavalent chromium is lower than the recommended limit and the risk of carcinogenesis is within an acceptable range, the risk of non-carcinogenic effects among workers is significant Therefore, it is important to prevent this problem, by adequate ventilation and using respiratory masks.


Asunto(s)
Contaminantes Ocupacionales del Aire , Enfermedades Profesionales , Exposición Profesional , Soldadura , Contaminantes Ocupacionales del Aire/efectos adversos , Contaminantes Ocupacionales del Aire/análisis , Carcinogénesis , Carcinógenos , Estudios Transversales , Polvo/análisis , Humanos , Enfermedades Profesionales/inducido químicamente , Enfermedades Profesionales/diagnóstico , Enfermedades Profesionales/epidemiología , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Medición de Riesgo
15.
Int J Mol Sci ; 23(16)2022 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-36012318

RESUMEN

Zinc- and copper-containing welding fumes can cause systemic inflammation after exposure in humans. Recent ex vivo studies have shown that the observed inflammation originates from exposed immune cells. In vitro studies identified the soluble fraction of metal particles as the main effectors. Isolated perfused mouse lungs (IPLs) were perfused and ventilated for 270 min. Lungs were instilled with saline solution (control), welding fume particle suspension (WFs) or the soluble fraction of the welding fumes (SF-WFs). Bronchoalveolar lavage fluid (BALF) and perfusate samples were analyzed for cytokine levels and lung tissue mRNA expression levels were analyzed via RT-PCR. All lungs instilled with WFs did not complete the experiments due to a fatal reduction in tidal volume. Accordingly, IL-6 and MPO levels were significantly higher in BALF of WF lungs compared to the control. IL-6 and MPO mRNA expression levels were also increased for WFs. Lungs instilled with SF-WFs only showed mild reactions in tidal volume, with BALF and mRNA expression levels not significantly differing from the control. Zinc- and copper-containing welding fume particles adversely affect IPLs when instilled, as evidenced by the fatal loss in tidal volume and increased cytokine expression and secretion. The effects are mainly caused by the particles, not by the soluble fraction.


Asunto(s)
Contaminantes Ocupacionales del Aire , Soldadura , Contaminantes Ocupacionales del Aire/toxicidad , Animales , Cobre/farmacología , Citocinas/metabolismo , Gases/farmacología , Inflamación/etiología , Exposición por Inhalación , Interleucina-6/genética , Interleucina-6/farmacología , Pulmón/metabolismo , Ratones , ARN Mensajero/genética , Zinc/farmacología
16.
Environ Res ; 214(Pt 4): 114152, 2022 11.
Artículo en Inglés | MEDLINE | ID: mdl-36041537

RESUMEN

The present systematic review aimed to evaluate the associations between welding fumes exposure and changes in oxidative stress [superoxide dismutase (SOD) and malondialdehyde (MDA)] and DNA damage [8-hydroxy-2'-deoxyguanosine (8-OHdG) and DNA-protein crosslink (DPC)] markers in professional welders (PROSPERO CRD42022298115). Six electronic bibliographic databases were searched from inception through September 2021 to identify observational epidemiological studies evaluating the association between welding fumes exposures and changes in oxidative stress and DNA damage in professional welders. Two reviewers independently assessed the risk of bias and certainty of the evidence. A narrative synthesis of results was conducted using the Synthesis Without Meta-analysis (SWiM) method. Pooled mean differences with 95% confidence intervals were calculated in a random-effects meta-analysis for the outcomes of interest in the review. From 450 studies identified through the search strategy, 14 observational epidemiological studies were included in the review. Most studies reported significantly higher welding fumes levels in welders than in controls. The narrative synthesis results of SOD showed a significant difference between welders and controls, while the meta-analysis results of MDA did not show a significant difference between the studied groups (MD = 0.26; 95% CI, -0.03, 0.55). The meta-analysis results of 8-OHdG (MD = 9.38; 95% CI, 0.55-18.21) and DPC (MD = 1.07; 95% CI, 0.14-2) revealed significantly differences between the studied groups. The included studies were at high risk of exclusion and confounding bias. The certainty of the evidence for oxidative stress and DNA damage results were very low and moderate, respectively. Exposure to welding fumes and metal particles is associated with DNA damage in professional welders, and 8-OHdG and DPC might be considered reliable markers to assess DNA damage resulting from exposure to welding fumes. We recommend, however, that the evaluation of oxidative stress resulting from welding fumes exposure not be solely based on MDA and SOD.


Asunto(s)
Contaminantes Ocupacionales del Aire , Exposición Profesional , Soldadura , 8-Hidroxi-2'-Desoxicoguanosina , Contaminantes Ocupacionales del Aire/análisis , Contaminantes Ocupacionales del Aire/toxicidad , Biomarcadores/análisis , Daño del ADN , Gases/análisis , Humanos , Obreros Metalúrgicos , Exposición Profesional/efectos adversos , Exposición Profesional/análisis , Estrés Oxidativo , Superóxido Dismutasa
17.
Arch Toxicol ; 96(12): 3201-3217, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35984461

RESUMEN

Thermal spray coating is an industrial process in which molten metal is sprayed at high velocity onto a surface as a protective coating. An automated electric arc wire thermal spray coating aerosol generator and inhalation exposure system was developed to simulate an occupational exposure and, using this system, male Sprague-Dawley rats were exposed to stainless steel PMET720 aerosols at 25 mg/m3 × 4 h/day × 9 day. Lung injury, inflammation, and cytokine alteration were determined. Resolution was assessed by evaluating these parameters at 1, 7, 14 and 28 d after exposure. The aerosols generated were also collected and characterized. Macrophages were exposed in vitro over a wide dose range (0-200 µg/ml) to determine cytotoxicity and to screen for known mechanisms of toxicity. Welding fumes were used as comparative particulate controls. In vivo lung damage, inflammation and alteration in cytokines were observed 1 day post exposure and this response resolved by day 7. Alveolar macrophages retained the particulates even after 28 day post-exposure. In line with the pulmonary toxicity findings, in vitro cytotoxicity and membrane damage in macrophages were observed only at the higher doses. Electron paramagnetic resonance showed in an acellular environment the particulate generated free radicals and a dose-dependent increase in intracellular oxidative stress and NF-kB/AP-1 activity was observed. PMET720 particles were internalized via clathrin and caveolar mediated endocytosis as well as actin-dependent pinocytosis/phagocytosis. The results suggest that compared to stainless steel welding fumes, the PMET 720 aerosols were not as overtly toxic, and the animals recovered from the acute pulmonary injury by 7 days.


Asunto(s)
Contaminantes Ocupacionales del Aire , Soldadura , Ratas , Animales , Masculino , Acero Inoxidable/toxicidad , Contaminantes Ocupacionales del Aire/toxicidad , FN-kappa B , Actinas , Factor de Transcripción AP-1 , Ratas Sprague-Dawley , Aerosoles y Gotitas Respiratorias , Soldadura/métodos , Exposición por Inhalación/efectos adversos , Pulmón , Polvo , Inflamación/patología , Citocinas , Clatrina/farmacología
18.
Artículo en Inglés | MEDLINE | ID: mdl-35805612

RESUMEN

Acute respiratory illness caused by exposure to welding-associated zinc oxide fumes is known as metal fume fever (MFF). MFF is generally characterized as a self-limiting disease. Few studies have reported chemical pneumonitis associated with zinc fume inhalation. We report a case study involving severe episodes of MFF accompanied by chemical pneumonitis due to the inhalation of zinc oxide fumes while operating an arc welder. A 54-year-old man developed flu-like symptoms after arc welding galvanized steel in a poorly ventilated area. Despite intravenous antibiotics therapy, his clinical course worsened, and his urine zinc concentration was remarkably elevated (3579 µg/24 h; reference range, 0-616 µg/24 h). A chest computed tomography revealed extensive consolidation, ground-glass opacity in the lungs, and right pleural effusion. After corticosteroid treatment, the patient's symptoms and radiologic findings significantly improved. It should be noted that the inhalation of zinc oxide fumes can occasionally induce acute lung injury via inflammatory responses and oxidative stress.


Asunto(s)
Contaminantes Ocupacionales del Aire , Bronquitis , Neumonía , Soldadura , Óxido de Zinc , Bisinosis , Gases/análisis , Humanos , Exposición por Inhalación/efectos adversos , Exposición por Inhalación/análisis , Masculino , Obreros Metalúrgicos , Persona de Mediana Edad , Neumonía/inducido químicamente , Neumonía/diagnóstico por imagen , Zinc
19.
J Environ Public Health ; 2022: 1508523, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35859574

RESUMEN

Welders are exposed to metal ions or oxides through direct contact at occupational sites or indirectly through uptake from contaminated dust or air. This study was a case-control study designed to assess the levels of some heavy metals and the hematological profile of welders (cases) as compared to nonwelders (controls) from Bibiani Anhwiaso Bekwai District of Ghana, comparatively to determine whether their values are within acceptable international range. A quantitative-based survey using structured questionnaires was used to collect demographic data from purposively selected welders (n = 40) and nonwelders (n = 40) from the study area. Five (5 mL) blood samples were collected from the study participants and analyzed for blood cell count as well as levels of Mn, Fe, Pb, and Zn. There were no significant differences in the Mn, Zn, and Fe levels between the welders and nonwelders (p=0.431, 0.53 vs. 0.23 mg/L, p=0.05, 0.41 vs. 0.15, p=0.886, 1.82 vs. 1.11). The level of Pb was, however, significantly lower among welders compared to the nonwelders (p=0.016, 0.09 < 0.3 mg/L). The total white blood cell count did not differ significantly between welders and nonwelders (p=0.365, 5.16 vs. 4.85 × 109/L). However, the mixed cell fraction was significantly higher among welders compared to nonwelders (p=0.027, 0.34 × 109/L > 0.28 × 109/L). Red blood cell count and indices showed no significant differences between the welders and nonwelders. Hemoglobin levels in welders were, however, higher (14.47 g/dL) but this was not statistically significant compared to their nonwelder counterparts (13.85 g/dL). It was concluded from the study that welders in Bibiani Anhwiaso Bekwai District of the Western Region of Ghana had elevated levels of Pb in their bodies. This was associated with an increase in mixed white blood cell fraction platelets. However, the recorded levels were within the accepted physiological limits suggesting that the heavy metal exposure of welders had no clinically pathological significance.


Asunto(s)
Contaminantes Ocupacionales del Aire , Metales Pesados , Exposición Profesional , Soldadura , Contaminantes Ocupacionales del Aire/análisis , Estudios de Casos y Controles , Ghana , Humanos , Iones , Hierro , Plomo , Manganeso/análisis , Obreros Metalúrgicos , Zinc
20.
Am J Epidemiol ; 191(10): 1753-1765, 2022 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-35872594

RESUMEN

We investigated the association between exposure to welding fumes and the risk of biliary tract, male breast, bone, and thymus cancer, as well as cancer of the small intestine, eye melanoma, and mycosis fungoides, among men in a European, multicenter case-control study. From 1995-1997, 644 cases and 1,959 control subjects from 7 countries were studied with respect to information on welding and potential confounders. We linked the welding histories of the participants with a measurement-based exposure matrix to calculate lifetime exposure to welding fumes. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models, conditional on country and 5-year age groups, and adjusted for education and relevant confounders. Regular welding was associated with an increased risk of cancer of the small intestine (OR = 2.30, 95% CI: 1.17, 4.50). Lifetime exposure to welding fumes above the median of exposed controls was associated with an increased risk of cancer of the small intestine (OR = 2.00, 95% CI: 1.07, 3.72) and male breast (OR = 2.07, 95% CI: 1.14, 3.77), and some elevation in risk was apparent for bone cancer (OR = 1.92, 95% CI: 0.85, 4.34) with increasing lifetime exposure to welding fumes. Welding fumes could contribute to an increased risk of some rare cancers.


Asunto(s)
Contaminantes Ocupacionales del Aire , Neoplasias , Exposición Profesional , Soldadura , Contaminantes Ocupacionales del Aire/efectos adversos , Estudios de Casos y Controles , Humanos , Masculino , Neoplasias/inducido químicamente , Neoplasias/epidemiología , Exposición Profesional/efectos adversos , Oportunidad Relativa
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...