1. Published studies show that cyanobacteria have higher Fe requirements than eukaryotic algae. To test whether Fe availability can affect formation of a cyanobacterial bloom, a strong Fe chelator, oxine (8-hydroxyquinoline, C 9 H 7 NO), was added to enclosures in eutrophic Lake 227 in the Experimental Lakes Area (ELA) (northwestern Ontario). 2. Aphanizomenon schindlerii growth was suppressed, and growth of eukaryotic chlorophytes significantly promoted in enclosures to which oxine had been added. Significant eukaryotic growth did not occur in enclosures treated with ammonium, suggesting that N supplied by degradation of oxine was not responsible for eukaryotic success in the oxine enclosures. 3. In situ Fe 2+ measurements were unreliable because of interference from high concentrations of dissolved organic compounds. However, oxine rapidly promoted oxidation of Fe 2+ to Fe 3+ in deionised water, suggesting that rapid removal of Fe 2+ also occurred in the oxine-treated enclosures. 4. In batch cultures, 10 lM M Fe and 10 lM M oxine (a 1 : 1 ratio) completely inhibited the growth of the cyanobacteria Synechococcus sp. and Anabaena flos-aquae and the chlorophytes Pseudokirchneriella subcapitata and Scenedesmus quadricauda. Increasing Fe 10-fold to 100 lM M Fe completely and partially reversed oxine inhibition in the two chlorophytes but could not overcome inhibition of the cyanobacteria, indicating that inhibition was Fe-mediated at least in the eukaryotes. Since oxine binds Fe 3+ in a 1 : 3 ratio (Fe : oxine), inhibition at a 1 : 1 ratio indicates that not all of the Fe is bound, and a mechanism involving Fe other than chelation was at least partly responsible for inhibition. 5. Collectively, the enclosure and laboratory results suggest that the outcome of competition between cyanobacteria and eukaryotic algae in the oxine-treated enclosures in Lake 227 was likely a result of decreased availability of Fe, especially Fe 2+ . 6. The results suggest that remediation methods that dramatically restrict the supply rate of Fe 2+ could reduce the relative abundance of cyanobacteria in eutrophic systems.

It is of great significance to study the porosity and permeability properties of medium and low-rank coal. The porosity and permeability in confining stress experiments were used to simulate the porosity and permeability variations of coal samples under different depth conditions. The pore structure of Baoqing coal samples is greatly affected by the confining pressure, and the pores and micro cracks are more easily compressed. Based on the experimental data of mercury intrusion porosimetry (MIP) and nitrogen adsorption (NA), the pore size distributions (PSDs) of medium and low-rank coals were studied. High mercury intrusion pressure would lead to coal matrix compression. Therefore, the pore volume calculated by MIP data was corrected by NA data. The PSDs characteristics of Jixi (JX) coal and Baoqing (BQ) coal samples are obtained from the revised pore volume, and the dominant pores of medium and low-rank coals are obtained. The results show that JX coal has higher spatial heterogeneity, connectivity and pore autocorrelation. Micro fractures have an influence on the autocorrelation and heterogeneity of coal samples, especially for BQ coal samples.

Background: Therapeutic lateral neck dissection (LND) is recommended in papillary thyroid carcinoma (PTC) patients with clinically lateral lymph node metastasis (LLNM), whether underwent level V LND remains controversial for lacking of sensitive predicting system. BRAF V600E mutation is associated with aggressive tumor behavior, recurrence, and disease-specific mortality of PTC. However, the relationship between BRAF V600E mutation and level V LNM is unclear. Methods: Univariate and multivariate analyses were retrospectively conducted on the potential predictive factors of 252 PTC patients who underwent initial treatment of neck lymph node dissection from September 2015 to October 2018 in our institute. BRAF V600E mutation and the clinicopathological characteristics of the two groups were compared. Results: LLNM was presented in 208 (82.5%) patients and level II-V LNM was present in 42.8%, 71.2%, 85.1%, 17.8% patients, respectively. BRAF V600E mutation was observed in 188 (74.6%) patients and was significantly associated with patients' age, lymphocytic thyroiditis, capsule invasion, bilateral central lymph node metastasis (CLNM) and level V LNM in PTC. Univariate analysis revealed that lymphocytic thyroiditis, tumor size, number of CLNM, Level II LNM, Level III LNM, simultaneous Level II+III, simultaneous Level III+IV and simultaneous Level II+III+IV were significantly correlated with Level V LNM. In addition, multivariate analysis revealed that tumor size ≥2.5 cm, number of CLNM≥3, level II metastases and BRAF V600E mutation were independent Level V LNM predictors (odds ratio 3.910, 3.660, 8.410, 0.439; 95% CI 1.737-10.135, 1.054-12.713, 1.233-57.355, 0.280-0.827, respectively). Conclusion: In summary, we presented several independent predictive factors for level V LNM in PTC patients. We constructed a risk prediction model consisting of tumor size ≥2.5 cm, number of CLNM≥3 and level II metastases and BRAF V600E mutation that may guide surgeons to evaluate the nodal status in PTC and perform tailored therapeutic LND.

Investigation on the pore-fracture features and crack propagation behavior of coal is necessary to prevent coal mine disasters. The pore structure features of coal samples taken from high gas seam were obtained by mercury injection porosimetry (MIP) and gas adsorption methods. The process of deformation and failure for coal samples under three-point bending conditions were obtained. The results demonstrate that the adsorption pores with diameter less than 100 nm are the most developed and their surfaces are the roughest (the average surface fractal dimension Ds is 2.933). The surface of micro-cracks is smoother (Ds is 2.481), which is conducive to gas seepage. It may be the explanation for that 14-3# coal seam is a high gas seam, while there was almost no gas outburst accident so far. At the initial stage of crack propagation, the main crack on the coal sample expanded along the direction of the natural cracks. In the process of crack propagation, the surface fractal dimension of the main crack increased, suggesting that the bending degree of the main crack enhanced. The brittle characteristics of coal samples can be reflected by the ratio of the dissipated energy to the accumulated energy.

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