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Cadmium exposure is associated with renal dysfunction and bone damage. Chronic kidney disease and bone loss are also related to parathyroid hormone (PTH). However, whether cadmium exposure affect PTH level is not completely understood. In this study, we observed the association between environmental cadmium exposure and PTH levels in a Chinese population. A ChinaCd study was performed in China in 1990s which included 790 subjects living in heavily, moderately and low cadmium polluted area. 354 of them (121 men and 233 women) also had the data of serum PTH. The cadmium levels in blood (BCd) and urine (UCd) were determined by flame atomic absorption spectrometry. Serum PTH was detected by immunoradiometric assay. Renal function was assessed based on urinary N-acetyl-β-d-glucosaminidase (UNAG), β2-microglobulin (UBMG) and urinary albumin (UALB). The median BCd and UCd levels were 4.69 μg/L and 5.50 μg/g creatinine. The BCd, UCd, UNAG, UBMG and UALB levels in subjects with low PTH (< 5.0 ng/L) were significantly higher than those with PTH ≥ 5.0 ng/L (p < 0.05 or p < 0.01). Spearman correlation analysis also showed that UCd level was negatively correlated to PTH levels (r = −0.17, p = 0.008) in women. A weak correlation was also observed between PTH level and BCd in women (r = −0.11, p = 0.09) and UBMG in total population (r = −0.114, p = 0.07). Univariable and mutivariable logistic regression analysis both demonstrated that high BCd (> 10 μg/L) (odds ratio (OR) = 2.26, 95% confidence interval (CI):1.10–4.63; OR = 2.36, 95%CI: 1.11–5.05) and UCd level (> 20 μg/g cr) (OR = 2.84, 95% CI:1.32–6.10; OR = 2.97, 95%CI: 1.25-7.05) were associated with high risk of low PTH. Our data showed that environmental cadmium exposure was associated with low PTH level. [ABSTRACT FROM AUTHOR]

Nitrogen and phosphorus are critical for the vegetation ecosystem and two of the most insufficient nutrients in the soil. In agriculture practice, many chemical fertilizers are being applied to soil to improve soil nutrients and yield. This farming procedure poses considerable environmental risks which affect agricultural sustainability. As robust soil microorganisms, plant growth-promoting rhizobacteria (PGPR) have emerged as an environmentally friendly way of maintaining and improving the soil's available nitrogen and phosphorus. As a special PGPR, rhizospheric diazotrophs can fix nitrogen in the rhizosphere and promote plant growth. However, the mechanisms and influences of rhizospheric nitrogen fixation (NF) are not well researched as symbiotic NF lacks summarizing. Phosphate-solubilizing bacteria (PSB) are important members of PGPR. They can dissolve both insoluble mineral and organic phosphate in soil and enhance the phosphorus uptake of plants. The application of PSB can significantly increase plant biomass and yield. Co-inoculating PSB with other PGPR shows better performance in plant growth promotion, and the mechanisms are more complicated. Here, we provide a comprehensive review of rhizospheric NF and phosphate solubilization by PGPR. Deeper genetic insights would provide a better understanding of the NF mechanisms of PGPR, and co-inoculation with rhizospheric diazotrophs and PSB strains would be a strategy in enhancing the sustainability of soil nutrients. [ABSTRACT FROM AUTHOR]

An experiment was conducted in a 20-level building to study the individual ascent speed on long stair. 165 college students, including 51 female students and 114 male students, took part in the experiment. Their ascent speeds and heart rates were recorded during they traveled upward. The experimental results show that their ascent speeds decrease continuously for the first 13-14 levels, then the ascent speeds keep at around 0.68 m/s for the males and 0.52 m/s for the females. Further study was conducted to explore the factors that might affect the ascent speeds on long stair. For the males, their ascent speeds show no obvious correlation with their body mass index and their scores of physical fitness test. For the females, it is observed that those who are overweight or fail in physical fitness test have the lowest ascent speed. After traveling upward around 18 levels, the average heart rates increase to 135 bpm and the average relative heart rates increase to 60% for the males, while the average heart rates increase to 150 bpm and the average relative heart rates increase to 70% for the females. Moreover, participates are more likely to use handrail for assistance as they move upward on higher levels. [ABSTRACT FROM AUTHOR]