Efficacy and safety study of ultrasound guided microwave ablation of large benign thyroid nodules

Objective To retrospectively evaluate the efficacy and safety of microwave ablation （MWA）in the treatment of large benign thyroid nodules. Methods Patients with large thyroid nodules who underwent ultrasound- guided MWA at Jiangsu Province Hospital and Jiangsu Province Official Hospital from March 2013 to October 2018 were included. A total of 191 patients with 397 nodules were enrolled. All nodules were confirmed as benign by ultrasound-guided fine-needle aspiration cytology（FNA）， with the main nodule volume＞20 mL. Intraoperative and postoperative complications were recorded. Nodule volume was assessed at 1，3，6，12，and 24 months post-treatment. Volume changes and volume reduction rate（VRR）were compared among nodules of different compositions and sizes. The correlation between ablation energy and VRR was analyzed based on nodule volume and composition.Results Over time，the VRR of all three nodule types（solid group 77 cases；cystic group 95 cases；mixed group 19 cases）progressively increased，with significant effects observed for time ，group，and their interaction（Ftime=39.288，Ptime＜0.01；Fgroup=6.177，Pgroupinteraction=4.299，Pinteraction＜0.01）. When stratified by volume［（20-30 mL group（95 cases）； ＞30-40 mL group（45 cases）；＞40 mL group（51 cases）］，significant effects were also found for time，group，and interaction（Ftime= 159.085，Ptime ＜0.01；Fgroup=34.861，Pgroup ＜0.01；Finteraction= 10.323，Pinteraction ＜0.01）. Correlation analysis showed that both total microwave energy and energy per unit volume were negatively correlated with VRR at 24 months（PConclusion MWA is a safe and effective treatment for large benign thyroid nodules. Greater cystic content and larger initial nodule volume were associated with better ablation outcomes. Ablation energy was negatively correlated with VRR

Study on the influence mechanism of calcination time on cementitious activity of coal gangue-based grouting material

In order to improve the activity of coal gangue as a key cementitious component in grouting materials, this study investigated coal gangue calcined at different durations under 800 °C. The coal gangue-based geopolymers were prepared through alkaline activation, and their compressive strength, X-ray diffraction (XRD) patterns, and Fourier transform infrared (FTIR) spectra were analyzed to systematically elucidate the effect of calcination time on the gelling activity of coal gangue. The results indicated that coal gangue exhibited higher gelling activity after 2 hours of calcination but underwent a notable decline at 4 hours, followed by a gradual increase after 6 hours; calcination facilitated the transformation of kaolinite in coal gangue into reactive amorphous metakaolin, whereas prolonged calcination led to the conversion of metakaolin into less active mullite; additionally, the reduction of residual carbon during calcination contributed to the gradual recovery of gelling activity

Metacommunity ecology meets bioassessment : Assessing spatio-temporal variation in multiple facets of macroinvertebrate diversity in human-influenced large lakes

Highlights • We examined drivers of 6 biotic metrics in a metacommunity context in two large lakes. • The relative roles of spatial, human-induced and natural factors were quantified. • The roles of spatial variables are comparable with local environmental conditions. • The relative roles of different drivers varied substantially among seasons. • Spatial processes, natural conditions and temporal variation should be considered.Metacommunity theory emphasizes that local communities are jointly affected by environmental filtering and spatial processes. However, the roles of spatial processes are often given insufficient attention in bioassessment practices, which may bias the assessments of ecological status based on biotic metrics. Here, we quantified the relative importance and the seasonal stability of spatial processes, natural conditions and human-induced factors in structuring variation in different bioassessment metrics based on macroinvertebrate communities. Our study systems were two extensively sampled large and shallow lakes with strong nutrient gradients related to human disturbance. The roles of different drivers were examined for three kinds of indicators: general diversity, trait-based and taxonomic distinctness metrics, and their performance in characterizing human disturbance was evaluated. Overall, human-induced and spatial factors were all important in explaining variation in the three types of bioassessment metrics. Contrary to our expectations, however, we found that the importance of spatial processes on bioassessment metrics can be comparable to the effects of local environmental conditions at the within-lake scale. Furthermore, the results showed substantial seasonal variability in the relative roles of different drivers, which might be linked to life-cycle seasonality of macroinvertebrates. As expected, trait-based metrics generally were best associated with human-induced variables in both lakes, whereas general diversity and taxonomic distinctness metrics performed poorly. The low effectiveness of taxonomic distinctness metrics might due to low species richness associated with high nutrient levels. To conclude, our results suggest that bioassessment cannot exclusively rely on the idea of environmental filtering even if we focus on fine spatial scales. We hence strongly urge that spatial processes, natural drivers and temporal variability should be better considered in combination in the development and application of bioassessment approaches. In addition, taxonomic distinctness measures should be used with caution, especially for the ecosystems and organism groups typically characterized by low species richness

Use of a Generalized Additive Model to Investigate Key Abiotic Factors Affecting Microcystin Cellular Quotas in Heavy Bloom Areas of Lake Taihu

Lake Taihu is the third largest freshwater lake in China and is suffering from serious cyanobacterial blooms with the associated drinking water contamination by microcystin (MC) for millions of citizens. So far, most studies on MCs have been limited to two small bays, while systematic research on the whole lake is lacking. To explain the variations in MC concentrations during cyanobacterial bloom, a large-scale survey at 30 sites across the lake was conducted monthly in 2008. The health risks of MC exposure were high, especially in the northern area. Both Microcystis abundance and MC cellular quotas presented positive correlations with MC concentration in the bloom seasons, suggesting that the toxic risks during Microcystis proliferations were affected by variations in both Microcystis density and MC production per Microcystis cell. Use of a powerful predictive modeling tool named generalized additive model (GAM) helped visualize significant effects of abiotic factors related to carbon fixation and proliferation of Microcystis (conductivity, dissolved inorganic carbon (DIC), water temperature and pH) on MC cellular quotas from recruitment period of Microcystis to the bloom seasons, suggesting the possible use of these factors, in addition to Microcystis abundance, as warning signs to predict toxic events in the future. The interesting relationship between macrophytes and MC cellular quotas of Microcystis (i.e., high MC cellular quotas in the presence of macrophytes) needs further investigation

Two ultraviolet radiation datasets that cover China

Ultraviolet (UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization's measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes

Numerical Simulation and Experimental Study of Piston Rebound Energy Storage Characteristics for Nitrogen-Hydraulic Combined Impact Hammer

The objective of this study is to analyze the piston rebound energy storage characteristics of the nitrogen-hydraulic combined impact hammer and to investigate the manner in which the piston rebound energy is converted and utilized. The kinetic equation of the impact hammer system is established. A numerical calculation model is constructed based on AMEsim, which incorporates the piston, cylinders, reversing valve, accumulator, power source, drill rod, and impacted device. The performance experiment system is designed, the oil pressure experiment and the piston motion experiment are constructed, and the accuracy of the numerical calculation model is verified by comparing the numerical calculation results with the experimental results. This paper investigates the fundamental principles of the piston rebound energy storage and analyzes the relationship between the opening percentage of the reversing valve high-pressure port and the piston rebound energy storage at the outset of the rebound stage. Furthermore, the influence of the length of the piston middle section and the number of high-pressure grooves in the signal chamber on the piston rebound energy storage is investigated. Finally, the experimental comparison allows for an analysis of the influence of the piston rebound energy storage on the performance of the nitrogen-hydraulic combined impact hammer