[Prognostic value of lymph node ratio in survival of patients with stage III rectal cancer].

OBJECTIVE: To assess the prognostic value of lymph node ratio (LNR) in patients with stage III rectal cancer after curative resection. METHODS: A retrospective review of the clinicopathological data was performed in 161 patients with stage III rectal cancer who received curative surgical excision in our hospital from June 2005 to June 2010. The variables including LNR, age, gender, T stage, N stage, total number of dissected lymph nodes, number of metastatic lymph nodes, and positive rate of lymph node metastasis were studied through univariate and multivariate analyses, and the survival analysis was performed using Kaplan-Meier method and Log rank test. RESULTS: Multivariate analysis revealed that LNR, but not number of positive nodes or number of harvested lymph nodes, had independent prognostic value for overall survival and disease-free survival for patients with stage III rectal cancer. The overall survival in the LNR < 0.43 and LNR ≥ 0.43 groups was 75.8% and 41.3%, respectively (P < 0.01), while the disease-free survival was 68.8% and 40.3%, respectively (P = 0.001). CONCLUSIONS: The LNR is an independent prognostic factor for survival of patients with stage III rectal cancer, and is more efficient than the number of positive nodes and total number of dissected lymph nodes in the survival prediction.

[Temporal and Spatial Distribution Characteristics and Difference Analysis of Chromophoric Dissolved Organic Matter in Sediment Interstitial Water from Gangnan Reservoir].

The chromophoric dissolved organic matter (CDOM), the main component of dissolved organic matter, affects the morphological characteristics, migration, and conversion of pollutants in water. Based on UV-vis spectra and excitation emission matrix spectroscopy (EEMs) combined with the parallel factor analysis (PARAFAC), the spatial distribution and spectral characteristics were investigated and source analysis of CDOM was performed. Thus, the spatiotemporal differences in the CDOM in Gangnan Reservoir were analyzed. Results showed that a254, a260, a280, and a355 exhibited significant seasonal differences in Gangnan Reservoir, and the order of CDOM concentrations was summer > spring > autumn > winter. There are significant seasonal differences in the E2/E3, E3/E4, E4/E6, and SR of interstitial water CDOM. The concentrations of E2/E3, E3/E4, E4/E6, and SR were high in winter and low in summer. E2/E3 and E3/E4 in autumn and winter were significantly higher than those in spring and summer, and the E3/E4 in autumn and winter was greater than 3.5, which indicates that the CDOM of the autumn and winter sediments has a smaller molecular weight and a lower degree of humification. Protein-like substances (C1), short-wave fulvic acid (C2), and degraded humic substances (C3) were identified by the PARAFAC model, and there was a significant positive correlation among the three fluorescent components (P<0.001). The total fluorescence intensity of CDOM and the fluorescence intensity of each fluorescent component show significant seasonal differences. The total fluorescence intensity and the fluorescence intensity of each component show the highest levels in spring, followed by autumn and winter, and the lowest levels in summer. The proportion of each fluorescent component in autumn and winter and that of each fluorescent component in spring and summer showed no significant difference. There was a significant difference in the proportion of each fluorescent component between autumn/winter and spring/summer. The BIX and FI of CDOM for autumn and winter were higher than those for spring and summer, indicating that the autogenous source of CDOM in autumn and winter is stronger than that in spring and summer, which was consistent with the result of HIX. PCA and Adonis analysis showed that the spectral characteristics of CDOM exhibited obvious seasonal differences (P<0.001). Moreover, the C1, C2, and C3 and water quality parameters (NH4+, NO3-, NO2-, TDN, and TDP) exhibited significant correlation based on linear regression. The results could provide technical support for the control of organic carbon pollution sources and water quality management in Gangnan Reservoir.

[Spatial Distribution Characteristics and Driving Factors of Aerobic Denitrification Bacterial Community Structure from Baiyangdian Lake in Xiong'an New Area During the Winter Freezing Period].

To isolate the aerobic denitrification bacteria suitable for water quality in the low-temperature period of Baiyangdian Lake, a water quality investigation and bioinformatics analysis of the aerobic denitrification bacterial community were carried out using a MiSeq high-throughput sequencing technique based on napA. Moreover, α-diversity, ß-diversity, and network analyses were also carried out. The results showed significant differences in the water quality of different sampling sites in Baiyangdian Lake, and the estuary area exhibited the highest nitrogen concentration. α-diversity exhibited significant differences (P<0.05), and the abundance and diversity of ZZD and BH were the lowest. The operational taxonomic units of the water body mainly belonged to Proteobacteria (α-Proteobacteria, ß-Proteobacteria, and γ-Proteobacteria). Meanwhile, Venn diagram analysis indicated the community of aerobic denitrification bacteria exhibited significant differences, and variance inflation factor and redundancy analysis showed that temperature, dissolved oxygen, ammonia, nitrate, dissolved total phosphorus, and redox potential were the main environmental factors. Network analysis showed that symbiotic relationships accounted for a major proportion of the microbial network. Mantel test analysis shows that temperature, redox potential, nitrate, ammonia, dissolved total phosphorus, and iron and manganese are the key factors affecting the evolution of modular community structure. From all the results, the MiSeq high-throughput sequencing technique based on the napA gene was an effective tool to explore the changes of aerobic denitrification bacterial community structure, which could supply a reference to isolate the "directional-accurate-efficient" aerobic denitrification bacterial agent in the future.