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Inflammatory, Hypersensitivity and Immune Lung Diseases, including Parasitic Diseases.
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
Funahashi et al. (1984) studied two men exposed to silicon carbide for many years, m a factory making refractory bricks. They developed reticulonodular densities in the lungs and dyspnoea. A biopsy in one showed a large amount of black material in fibroid alveolar septa and ferruginous bodies. Six different carbides were present and a trace of tungsten. They concluded "it is possible that some silicon carbides are more fibrogenic than others and that the previous negative animal study was due to this factor. At any rate it is important to be aware that workers who are exposed only to silicon carbide for prolonged periods may develop pneumoconiosis."
Inhalation Toxicity of Metal Particles and Vapors
Published in Jacob Loke, Pathophysiology and Treatment of Inhalation Injuries, 2020
It is used in high-temperature alloys and in permanent magnets. Its salts are useful in paint driers, as catalysts, and in the production of numerous pigments for use in glass and porcelain. Cemented carbide (hard metal) tools, used in metalcutting operations, are produced primarily from tungsten carbide and 2-25% cobalt powders. Cobalt is an essential element in that 1 μg of vitamin B12 contains 0.0434 μg of cobalt. Vitamin B12 is essential in the prevention of pernicious anemia.
11C, 13N, and 15O Tracers
Published in Garimella V. S. Rayudu, Lelio G. Colombetti, Radiotracers for Medical Applications, 2019
Roy S. Tilbury, Alan S. Gelbard
When methane is irradiated with deuterons the principal 13N containing products are NH3 (95%), CH3NH2 (2%), HCN (<3%), and C2H5NH2 (0.2%), as obtained by bubbling the irradiated gas through water.79 This solution may be distilled to give pure 13NH3.84 Alternatively, metallic carbides (e.g., A14C3) can be irradiated with deuterons and 13NH3 generated by dissolving the carbide in dilute alkali.78 These methods of 13NH3 production, however, give a product of lower specific activity than the (p,4He) reaction on water, due to the presence of nitrogen impurities in the targets.
Long-term effects of tungsten carbide (WC) nanoparticles in pelagic and benthic aquatic ecosystems
Published in Nanotoxicology, 2018
Mikael T. Ekvall, Jonas Hedberg, Inger Odnevall Wallinder, Lars-Anders Hansson, Tommy Cedervall
In conclusion, our results highlight the importance of long-term toxicity tests to evaluate the effects of NPs once released to natural ecosystems. Although we were unable to detect any acute, short-term, effects of tungsten carbide NPs on D. magna, long-term exposures resulted in both reduced survival and strong effects on reproduction and thereby fitness. This effect may cascade through the aquatic food-web and eventually pose even greater risks for the aquatic ecosystem. Due to the considerable differences in acute vs. long-term exposures revealed here, our results clearly emphasize the need for more focus on long-term studies on the effects of NPs in natural systems. Our results also highlight the need of evaluating various exposure scenarios, and we here show that by inducing resuspension of the particles, mimicking wave and current actions in natural systems, the effects on D. magna became considerably stronger. Hence, by including these factors in our assays we can create more natural exposure scenarios to assess the adverse effects of NPs once released into nature.
Exposure of calcium carbide induces apoptosis in mammalian fibroblast L929 cells
Published in Toxicology Mechanisms and Methods, 2021
Indranil De, Rajesh S, Avneet Kour, Henna Wani, Prashant Sharma, Jiban Jyoti Panda, Manish Singh
Easy availability, low cost and convenience of use make CaC2 the most commonly used artificial fruit ripener. CaC2, locally called as ‘Masala’, produces acetylene gas that has ripening effects similar to the natural plant hormone ethylene, responsible for natural fruit ripening which is an enzymatic and biochemical process involving the conversion of starch of fruits into sugar. Carbide is mostly used for ripening of fruits like mango, tomato, apple, banana, papaya and pineapple. In usual practice, small packets of CaC2 (2 g per Kg of fruit) are placed along with the raw fruits kept in wooden crates or buckets. This approach, usually adopted with mangoes, seems to be a relatively less harmful approach as the acetylene gas released from the CaC2 packets causes ripening effects on fruits and goes off. In this method, usually there is no direct contact of fruits with the CaC2, but this takes longer time and sometimes results in non-uniform or uneven ripening because fruits closer to the CaC2 packets get over ripened as compared to the fruits kept farther. Presently people are adopting some other approaches which involve sprinkling of CaC2 powder or spraying of CaC2 solution over raw fruits or instead dipping the entire fruit in CaC2 solution. These approaches involve direct contact of CaC2 with the fruits causing deposition over skin of fruits (Figure 1(C)) and may have toxic implications due to CaC2 itself and/or the associated impurities of arsenic which may cause harmful effects (Singh et al. 2011a; Tolins et al. 2014; Peters et al. 2017).
Inflammatory and coagulatory markers and exposure to different size fractions of particle mass, number and surface area air concentrations in the Swedish hard metal industry, in particular to cobalt
Published in Biomarkers, 2021
Lena Andersson, Alexander Hedbrant, Alexander Persson, Ing-Liss Bryngelsson, Bengt Sjögren, Leo Stockfelt, Eva Särndahl, Håkan Westberg
The study was performed at two Swedish hard metal industries, employing 130 and 1400 workers, respectively. The two industries use similar processes which cause similar variations in exposures. The production during the measurement days produced 18,500–44,000 pieces and 1,484,000–1,542,000 pieces of hard metal products, respectively. The hard metal details produced are based on tungsten carbide, where cobalt is used as a binder. The companies produce smaller details of cemented carbide materials for cutting work and rock drilling of 10–250 gram/piece and larger products for the car and aeroplane industry of 10–50 kg.