Abstract In the present study the white-rot fungi BP was selected to study the degradation of nitrogen heterocyclic compounds in real and simulated coking wastewater. The study incorporated analysis of the degradation process, mechanism of action of white-rot fungi on nitrogen heterocyclic compounds, changes of enzyme activity and white-rot fungi biomass growth rate in coking wastewater (simulated and actual). The results showed that the addition of ammonia nitrogen and phenol in simulated wastewater had insignificant effects on the degradation of indole. Moreover, the promoting effect of phenol on quinoline degradation was greater than the inhibition effects of ammonia nitrogen. Degradation rates of quinoline, indole and pyridine are consistent with the zero-order kinetics equation. It was also found that the addition of Mg (II) and Mn (II) promotes the degradation of quinoline by white-rot fungi in the actual wastewater, while degradation of pyridine was inhibited by three ions, out of which the inhibition of Cu (II) was the most obvious. Cu (II) was also found to have positive effects on the levels of activity of laccase enzyme secreted by the white-rot fungi as opposed to other metal ions tested. However, it was found to have inhibitory effects on the development of white-rot fungi, while Mg (II) and Mn (II) were found to promote the development of the white-rot fungi. The activity of the enzyme and the growth rate of the biomass of white-rot fungi first reached the maximum levels followed by a significant decline.

Present studies show that nitrate accumulation is the major factor influencing the water uptake by vegetables, but there is lack of knowledge on how the relationship between nitrate and water concentrations in different vegetable tissues. We determined nitrate accumulation and water content in vegetables of rape, Chinese cabbage, and spinach under different nitrogen levels (experiment I), 29 spinach cultivars (experiment II), and 27 rape cultivars (experiment III). The results from experiments I-III showed a highly linear relationship between nitrate accumulation and water content, and the levels thereof in different organs of the vegetables revealed that the petiole exhibited the best correlation between them compared with the root and leaf blade. These suggest that (1) vegetables with high water content have high nitrate content, (2) water content in the petiole can be used to screen cultivars with low levels of nitrate accumulation, and (3) increasing soil water content in agronomic practice is essential to decreasing nitrate accumulation in vegetables.

The problem concerning the nature and the function of the dead space is of basic importance for the full comprehension of the respiratory physiology and pathophysiology. To study the effect of an imposed external dead space on the optimal respiratory control system, we simulated the optimal neuro-muscular drive and respiratory signals, including instantaneous airflow and lung volume profiles, with dead space loading under hypercapnia. The dead space measurement model by Gray was employed and the human respiratory control simulator based on an optimality hypothesis was implemented. The ventilatory control simulations were performed with external dead space loading of 0, 0.4 and 0.8 liters under rest condition (Pico2=0%) and CO2 inhalation of 3% to 7%. The optimization of the respiratory signals and model behavior of the optimal respiratory control under dead space loading and hypercapnia were verified and found to be in general agreement with experimental findings.

To find Epstein-Barr virus (EBV) strains with genetic variations of EBV latent membrane protein 1 (EBV-LMP1) from nasopharyngeal carcinoma (NPC), the full-length DNA of LMP1 genes from 21 NPC biopsies obtained in Hunan province in southern China was amplified and sequenced. Our sequences were compared to those previously reported by the Clustal V method. Results showed that all 21 sequences displayed two amino acid changes most frequently in LMP1 of CD4+ T cell epitopes at codons 144 (F®I, 21/21) and 212 (G®S, 19/21) or (G®N, 2/21). We also show that type A EBV strain is prevalent in the cases of NPC from Hunan province with a 30-bp 18/21 deletion, and we highlight that this deletion resulted in loss of one of the CD4+ T cell-restricted epitopes. The other 3 sequences without this deletion all had a change at codon 344 (G®D). Furthermore, in the major epitope sequence of CD8+ T cells restricted by HLA-A2, all 21 sequences showed changes at codons 126 (L®F) and 129 (M®I). Our study discovered that one of the 21 sequence variations harbored a new change at codon 131 (W®C), and 5/21 specimens showed another novel change at codon 115 (G®A) in the major epitope sequence of CD8+ T cells restricted by HLA-A2. Our study suggests that these sequence variations of NPC-derived LMP1 may lead to a potential escape from host cell immune recognition, protecting latent EBV infection and causing an increase in tumorigenicity.