Effects of chromate on nitrogen removal and microbial community in two-stage vertical-flow constructed wetlands.

Nitrogen and chromium (Cr(VI)) pollution in waterbodies pose great threats to human health, and a cost-effective alternative with Cr(VI) and nitrogen simultaneous removal is still needed. This study investigated the influence of Cr(VI) on nitrogen removal in the two-stage vertical-flow constructed wetlands (TS-VFCWs) along with iron ore and woodchip, and explored relationship between Cr(VI) and nitrogen removal. The results showed that efficient Cr(VI) and nitrogen removal were simultaneously achieved in TS-VFCWs together with iron-ore and woodchip under 2 mg/L-Cr(VI), whereas 10 mg/L-Cr(VI) gave significant and recoverable inhibition of nitrogen removal. Cr(VI) supplementation promoted the beneficiation of Cr(VI)-reducing/resistant bacteria IMCC26207 and Bryobacter on iron-ore. Woodchip enriched Cr(VI)-reducing bacteria Streptomyces and Thiobacillus. XRD and XPS showed that abundant bound-Cr existed in the surface of iron ore and woodchip, and Cr(III) precipitation/oxide was the major product. High abundances of nitrifying and autotrophic/heterotrophic denitrifying bacteria ensured good nitrogen removal at Cr(VI) stress.

Discovering Geographical Flock Patterns of CO2 Emissions in China Using Trajectory Mining Techniques.

Carbon dioxide (CO2) emissions are considered a significant factor that results in climate change. To better support the formulation of effective policies to reduce CO2 emissions, specific types of important emission patterns need to be considered. Motivated by the flock pattern that exists in the domain of moving object trajectories, this paper extends this concept to a geographical flock pattern and aims to discover such patterns that might exist in CO2 emission data. To achieve this, a spatiotemporal graph (STG)-based approach is proposed. Three main parts are involved in the proposed approach: generating attribute trajectories from CO2 emission data, generating STGs from attribute trajectories, and discovering specific types of geographical flock patterns. Generally, eight different types of geographical flock patterns are derived based on two criteria, i.e., the high-low attribute values criterion and the extreme number-duration values criterion. A case study is conducted based on the CO2 emission data in China on two levels: the province level and the geographical region level. The results demonstrate the effectiveness of the proposed approach in discovering geographical flock patterns of CO2 emissions and provide potential suggestions and insights to assist policy making and the coordinated control of carbon emissions.

[Expression of neuropilin 2 in human colorectal carcinoma and its correlation with lymphangiogenesis and lymphatic metastasis of tumor].

OBJECTIVE: To explore the relationship between neuropilin 2 (NRP-2) and lymphangiogenesis and lymphatic metastasis of human colorectal carcinoma (CRC), as well as the expression of NRP-2 in CRC tissues. METHODS: A total of 55 cases of CRC, adjacent and normal tissues of surgical resection were randomly selected at our hospital from March 2010 to January 2012. All pathological findings were confirmed by histopathology. The expression of NRP-2 was detected with reverse transcription (RT)-PCR and immunohistochemistry in parenchymatous and surrounding malignant tissues. Then lymphangiogenesis was marked with D2-40 monoclonal antibody and microlymphatic density (MLD) counted. RESULTS: Significant differences of MLD existed between those of tumor region (39 ± 19) and tumor margin (53 ± 26, P < 0.01). Both the number and shape of lymphangiogenesis were different between the parenchymatous and surrounding tissues. The expression of NRP-2 had a positive correlation with MLD both at the protein level (r = 0.325, P < 0.05) and at the gene level (r = 0.545, P = 0.000). And it was also correlated with the differentiation degree, infiltrative degree, lymphovascular invasion, lymph node metastasis and Dukes tumor staging (all P < 0.05). CONCLUSION: The expression of NRP-2 may regulate lymphangiogenesis and it may play an important role in the incidence and development of CRC.