[Pollution and Irrigation Applicability of Surface Water from Wet, Normal, and Dry Periods in the Huixian Karst Wetland, China].

To reveal the hydrochemical characteristics of karst wetland located in a subtropical area and at lower elevations in China, 27 surface water samples were collected during three periods (wet, normal, and dry) in the Huixian karst wetland to investigate the distributions, pollution, and irrigation application of 12 inorganic ions and 10 heavy metals. Based on their concentrations, the Nemerow index and the four evaluation systems of the sodium adsorption ratio (SAR), sodium concentration (SC), permeability index (PI), and residual sodium carbonate (RSC) were applied to evaluate the pollution characteristics and irrigation application. It was found that the water type in this area was Ca2+-HCO3- and weakly alkaline. Regarding the 12 inorganic ions and 10 heavy metals, NH4+ exceeded the Chinese standards for drinking water with an exceedance rate of 25.93%, and the exceedance rates of Al, Mn, and Hg were 11.11%, 44.44%, and 37.04%, respectively. The spatiotemporal scaling effect on inorganic ions was lower than that of heavy metals, and the distributions of the inorganic ions and heavy metals were in the order of wet period > normal period > dry period. However, the surface water quality in the Huixian karst wetland was generally well-protected based on the pollution assessment. The Nemerow index ranged from 0.75 to 2.69, which recognized the main pollution contributors as NH4+, Mn, Al, and Hg with the contamination grade from slight pollution to moderate pollution, especially in the core area during the wet period. According to the limits of standards for irrigation water quality and environmental quality for surface water, as well as the evaluation results of the SAR, SC, PI, and RSC, the surface water in the Huixian karst wetland was generally suitable for irrigation, and the water quality in the dry period was better than that in the wet and normal periods. The surface water from site PH1 during the normal period with 19.1 µg·L-1 of Hg and site FH8 during the wet period with 13.7 mg·L-1 of NH4+ were not suitable for agricultural irrigation.

[Major Ionic Characteristics and Factors of Karst Groundwater at Huixian Karst Wetland, China].

To investigate the major ionic chemical characteristics and seasonal variations, 27 groundwater samples were collected from the wet season, flat season, and dry season during 2018-2019 in the Huixian Karst wetland, which is the largest low-altitude karst wetland in China. The single pollution standard index was applied to evaluate the groundwater pollution during different periods, and the major ionic factors of the karst groundwater were analyzed using the statistical analysis method, Gibbs diagram, and ion ratio. The results revealed that the groundwater samples were a weakly alkaline fresh water that were rich in Ca2+ and HCO3-. The average concentrations of the primary ions followed the order of flat season > wet season > dry season; meanwhile, the water quality in the dry season was better than that in the wet and flat seasons. The K+ and NO3- in the karst groundwater were mostly affected by the spatial distributions of the aquifers, and the Mg2+, SO42-, NO2-, NH4+, and TDS were related to the space-season scale. Na+, Ca2+, HCO3-, and Cl- were relatively stable ions in the karst groundwater. The hydrochemical characteristics were primarily determined by carbonate rock dissolution and were found to be the HCO3-Ca type, which accounted for 77.78%, 77.78%, and 88.89% in the wet season, flat season, and dry season, respectively. The karst groundwater was predominantly polluted by SO42-, NO3-, and NO2-; particularly, NO3- exhibited serious pollution points, and SO42- had heavy pollution points in the wet and flat seasons. The chemical composition of the karst groundwater was controlled mostly by water-rock interactions. Ca2+ and HCO3- primarily came from calcite dissolution, and the high concentrations of Mg2+ and SO42- in a few number of points were controlled by dolomite, dolomitic limestone, and pyrite. K+, Na+, SO42-, NO3-, and Cl- partly came from atmospheric precipitation, and Na+ and Cl- partly came from human activities; K+ was related to potash fertilizer, and the main source of NO3- was chemical fertilizer.

Combination of contrast-enhanced ultrasound and strain elastography to assess cytologically non-diagnostic thyroid nodules.

The aim of the present study was to investigate the benefits of combining contrast-enhanced ultrasound (CEUS) and strain elastography (SE) for the diagnosis of thyroid nodules with non-diagnostic fine-needle aspiration cytology (FNAC) results. Between October 2013 and March 2017, CEUS and SE were performed in 226 patients (236 thyroid nodules) with non-diagnostic FNAC results prior to thyroidectomy. The diagnostic value of CEUS, SE and their combination (CEUS+SE) in distinguishing malignant from benign thyroid nodules was evaluated, using surgical pathology as a reference. Receiver operating characteristic curve analysis was used to assess the diagnostic performance of CEUS, SE and CEUS+SE in determining malignant thyroid nodules. Subsequently, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of CEUS, SE and CEUS + SE were calculated. The malignancy rate in patients with thyroid nodules and non-diagnostic FNAC results was 26.3% in the present study. The sensitivity, specificity, PPV, NPV, accuracy and area under the curve in predicting malignant thyroid nodules were 80.6, 85.6, 66.7, 92.5, 84.3 and 0.831%, respectively, using SE alone; 59.7, 95.9, 84.1, 86.9, 86.4 and 0.778%, respectively, using CEUS alone; and 83.9, 89.1, 73.6, 94.5, 88.1 and 0.865%, respectively, using the combination of CEUS and SE. Overall, the combination of CEUS with SE resulted in higher sensitivity, NPV and accuracy in the diagnosis of cytologically non-diagnostic thyroid nodules compared with CEUS or SE alone.

The features of contrast enhanced ultrasound and BRAF V600E in papillary thyroid carcinoma.

BACKGROUND: BRAF V600E mutation was proved to be associated with thyroid cancer. Papillary thyroid carcinoma (PTC) with positive BRAF mutation might have a more aggressive behavior. We investigated the correlation of the contrast-enhanced ultrasound (CEUS) features with BRAF 600VE in PTC. METHODS: The medical records of 1,199 patients with 1,315 nodules who underwent CEUS prior to fine needle aspiration (FNA) from January 2016 to March 2018 were retrospectively reviewed. The features of their enhancement were assessed from eight aspects: degree of enhancement, method of enhancement, homogeneity of enhancement, completeness of enhancement, boundary of the enhanced lesions, shape of the enhanced lesions, size of the enhanced lesions, and wash out period of the enhanced lesions. The patients then examined for the BRAF V600E mutation using specimens obtained from FNA. RESULTS: BRAF mutations were found in 888 of 1,315 nodules. The CEUS features were significantly different between BRAF-positive and BRAF-negative nodules. The BRAF mutation positive nodules were more often with larger size, hypo-enhancement, centripetal enhancement, inhomogeneous enhancement, complete enhancement, blurred boundary, irregular shape, and with wash out period at preoperative CEUS than those without BRAF mutations (P<0.001). However, no significant correlation was showed in Spearman's rank correlation between the CEUS features and BRAF mutation, except for degree of enhancement, method pattern of enhancement, and completeness of complete enhancement. Multivariate analysis showed that centripetal (OR: 1.465, 95% CI: 1.129-1.903) and no significant enhancement (OR: 0.790, 95% CI: 0.639-0.977) were predictive for the presence of BRAF mutations. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of no significant enhancement and centripetal enhancement of CEUS for predicting BRAF mutation were 68.3%, 40.0%, 91.6%, 11.7%, and 72.4%, 35.1%, 37.8%, 70.0%, respectively. CONCLUSIONS: Our study indicated that preoperative thyroid nodule characteristics on CEUS might serve as a useful tool to BRAF mutation in PTC.

[Ultrasonic scores of conventional ultrasound and ultrasound elastography in the diagnosis of thyroid nodular lesions].

OBJECTIVE: To explore the values of total ultrasonic scores of conventional ultrasound and ultrasound elastography in the diagnosis of thyroid nodular lesions. METHODS: A total of 347 thyroid nodules proved by fine-needle aspiration cytology (FNAC) and surgery underwent preoperative conventional ultrasound and ultrasound elastography. The features on gray scale, color Doppler flow imaging (CDFI) and elastograms were documented and total ultrasonic scores recorded. RESULTS: Among 347 nodules, 184 nodules were benign and 163 malignant. Significant differences of total ultrasonic scores were found between thyroid carcinoma and benign nodular lesions including the parameters of nodular shape, edge, echoes, sound attenuation, psammous calcifications, internal blood flow and ultrasound elastography score. The higher the total ultrasonic scores, the more possibility of thyroid carcinoma was. By the analysis of receiver operating characteristic curve, the sensitivity, specificity and accuracy of distinguishing thyroid carcinoma from benign nodular lesions was 84.0%, 89.6% and 84.9% if the cut-off value of total ultrasonic scores was over 4. CONCLUSION: For the differential diagnosis of benign and malignant thyroid lesions, the total ultrasonic scores of conventional ultrasound and ultrasound elastography can offer greater values.