ABSTRACT
Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) play key roles in regulating testosterone secretion and spermatogenesis in male mammals, respectively, and they maintain the fertility of male animals by binding to their corresponding receptors. We designed and prepared a recombinant LH receptor (LHR) subunit vaccine and a recombinant FSH receptor (FSHR) subunit vaccine and used male Sprague Dawley (SD) rats as a model to examine their effects on testicular development, spermatogenesis, and testosterone secretion in prepubertal and pubertal mammals. Both vaccines (LHR-DTT and FSHR-DTT) significantly decreased the serum testosterone level in prepubertal rats (p < 0.05) but had no effect on the testosterone secretion in pubertal rats; both vaccines decreased the number of cell layers in the seminiferous tubules and reduced spermatogenesis in prepubertal and pubertal rats. Subunit vaccine FSHR-DTT decreased the sperm density in the epididymis in both prepubertal and pubertal rats (p < 0.01) and lowered testicular index and sperm motility in pubertal rats (p < 0.05), whereas LHR-DTT only reduced the sperm density in the epididymis in pubertal rats (p < 0.05). These results indicate that the FSHR subunit vaccine may be a promising approach for immunocastration, but it still needs improvements in effectiveness.
ABSTRACT
Nickel is a critical metal for global low-carbon energy transition, but its production processes require massive energy inputs and emit large amounts of pollutants. This study constructed life cycle inventories of the mainstream electrolytic nickel production chains in China at the industrial level and subsequently evaluated their environmental performance via a regionalised life cycle impact assessment method. Results show that environmental indicator results of the electrolytic nickel production from the leaching electrowinning method were 17.7%-40.2% lower than those from the grind and flotation electrolytic method. At the endpoint level, the nickel mining and beneficiation stages contributed 54.7%-65.91% of human health damage, 83.0%-84.7% of ecosystem quality damage and 80.8%-83.7% of resources damage. The key processes, including direct processes, cement input and energy consumption (e.g., electricity and coal), accounted for more than 62.1% of the impacts in the key midpoint categories. The potential environmental damage of China's nickel mining and beneficiation industry increased by 29.2% from 2010 to 2018 because of the growing trend of nickel ore demand. In the case that China's nickel metal recovery rate reaches the global average level, then approximately 3.83 × 102 Daly of human health damage, 59.83 Species·year of ecosystem quality damage and 1.64 × 108 $ of resources damage can be avoided annually. Strategies for promoting the full assimilation of renewable electricity, applying the clinker-free cemented backfill materials in the mining process, precious recovery by bioleaching from tailings and reusing waste rock as building materials are recommended. Meanwhile, extended producer responsibility should to be comprehensively implemented in the nickel-related industries to alleviate the environmental implications and nickel supply pressures from geo-mining.
