Imaging classification of prostate cancer with extracapsular extension and its impact on positive surgical margins after laparoscopic radical prostatectomy.

Abstract: To explore the impact of different imaging classifications of prostate cancer (PCa) with extracapsular extension (EPE) on positive surgical margins (PSM) after laparoscopic radical prostatectomy. Methods: Clinical data were collected for 114 patients with stage PT3a PCa admitted to Ningbo Yinzhou No. 2 Hospital from September 2019 to August 2023. Radiologists classified the EPE imaging of PCa into Type I, Type II, and Type III. A chi-square test or t-test was employed to analyze the factors related to PSM. Multivariate regression analysis was conducted to determine the factors associated with PSM. Receiver operating characteristic curve analysis was used to calculate the area under the curve and evaluate the diagnostic performance of our model. Clinical decision curve analysis was performed to assess the clinical net benefit of EPE imaging classification, biopsy grade group (GG), and combined model. Results: Among the 114 patients, 58 had PSM, and 56 had negative surgical margins. Multivariate analysis showed that EPE imaging classification and biopsy GG were risk factors for PSM after laparoscopic radical prostatectomy. The areas under the curve for EPE imaging classification and biopsy GG were 0.677 and 0.712, respectively. The difference in predicting PSM between EPE imaging classification and biopsy GG was not statistically significant (P>0.05). However, when used in combination, the diagnostic efficiency significantly improved, with an increase in the area under the curve to 0.795 (P<0.05). The clinical decision curve analysis revealed that the clinical net benefit of the combined model was significantly higher than that of EPE imaging classification and biopsy GG. Conclusions: EPE imaging classification and biopsy GG were associated with PSM after laparoscopic radical prostatectomy, and their combination can significantly improve the accuracy of predicting PSM.

Study on Bingham fractional damage model of backfill material under different moisture content conditions.

Filling mining technology is an important representative technology to realize green and low-carbon mining. The backfill materials have distinct rheological characteristics under the long-term action of formation loads and groundwater seepage. In order to study the creep characteristics of backfill materials under different moisture contents and reveal their aging-mechanical properties, based on the Riemann-Liouville fractional calculus and damage mechanics theory, the fractional element and damage variables are introduced to improve the traditional Bingham model, and the fractional Bingham creep damage model is proposed. Based on the experimental data of gangue cemented backfill under different moisture content, the parameters of the creep model are obtained by using user-defined function fitting and the least square method. The results show that the improved Bingham fractional creep damage model can describe the whole creep process of backfill materials under different moisture contents, and the rationality of the model is verified. Compared with the traditional Bingham model, the fitting degree of the Bingham fractional creep damage model is higher, which solves the problem that the traditional Bingham model cannot describe the nonlinear creep stage. Model parameter α and ξ increase with the increase of axial stress and moisture content. Under the same moisture content, η gradually increases with the increase of axial stress. This work has a certain reference significance for studying the mechanical properties and creep constitutive model of backfill materials containing water.

Creep characteristics and damage model of coal-rock combinations with different height ratios.

Numerous coal pillars are left after the coal mining process. The composite structure comprising a roof and coal pillar has prominent creep characteristics, which threaten safe underground mining. Therefore, the creep characteristics of coal-rock combinations should be studied to ensure the safety of quarry and surface. Uniaxial creep tests under static load axial pressure and different height ratios were performed using a self-designed rock creep disturbance test device to determine the effect of height ratio and axial pressure on the creep characteristics of coal-rock combinations. From the test results, a creep damage model for coal-rock combinations was established by combining the elastomer, fractional Kelvin body, plastic body, Abel dashpot, and modified nonlinear viscoplastic body; introducing damage variables D related to stress, height ratio, and time; and deriving a one-dimensional creep equation. An improved nonlinear least squares method based on pattern search was utilized to invert the creep parameters. The results of the creep equation calculation were fitted with the experimental results with good results. The creep curve with a height ratio of 2:1 was predicted with good results. The research results provide theoretical references for long-term stability analysis of rock engineering.

Prediction of extracapsular extension in prostate cancer using the Likert scale combined with clinical and pathological parameters.

Abstract: This study aimed to investigate the independent clinical, pathological, and radiological factors associated with extracapsular extension in radical prostatectomy specimens and to improve the accuracy of predicting extracapsular extension of prostate cancer before surgery. Methods: From August 2018 to June 2023, the clinical and pathological data of 229 patients with confirmed prostate cancer underwent radical prostatectomy from The Second Hospital of Yinzhou. The patients' multiparametric magnetic resonance imaging data were graded using the Likert scale. The chi-square or independent-sample T-test was used to analyze the related factors for an extracapsular extension. Multivariate analysis was used to identify independent factors associated with extracapsular extension in prostate cancer. Additionally, receiver operating characteristic curve analysis was used to calculate the area under the curve and assess the diagnostic performance of our model. The clinical decision curve was used to analyze the clinical net income of Likert scale, biopsy positive rate, biopsy GG, and combined mode. Results: Of the 229 patients, 52 had an extracapsular extension, and 177 did not. Multivariate analysis showed that the Likert scale score, biopsy grade group and biopsy positive rate were independent risk factors for extracapsular extension in prostate cancer. The area under the curves for the Likert scale score, biopsy grade group, and biopsy positive rate were 0.802, 0.762, and 0.796, respectively. Furthermore, there was no significant difference in the diagnostic efficiency for extracapsular extension (P>0.05). However, when these three factors were combined, the diagnostic efficiency was significantly improved, and the area under the curve increased to 0.905 (P<0.05). In the analysis of the decision curve, The clinical net income of the combined model is obviously higher than that of Likert scale, biopsy positive rate, and biopsy GG. Conclusion: The Likert scale, biopsy grade group and biopsy positive rate are independent risk factors for extracapsular extension in prostate cancer, and their combination can significantly improve the diagnostic efficiency for an extracapsular extension.

Mesoscopic structural damage and permeability evolution of Shale subjected to freeze-thaw treatment.

To study the mesoscopic damage and permeability evolution characteristics of rock under freeze-thaw (F-T) cycles, freeze-thaw cycle experiments were carried out of shale under different F-T temperatures and numbers of cycles, and nuclear magnetic resonance (NMR) and permeability experiments of shale were conducted thereafter. On the basis of these experiments, the pores and permeability of the F-T shale were analyzed, and the existing permeability model is modified and improved; Therefore, the mesoscopic damage evolution characteristics and permeability evolution law of the F-T shale are obtained. It was found that with increasing number of cycles, the pore structure of the rock samples changed as the pore size expanded and the number of pores increased, and the average porosity also increased correspondingly. The influence of the F-T cycle temperature on the shale permeability was not as notable as that of the number of F-T cycles. Based on the SDR-REV permeability model, the spectral area ratio parameters of large pores and fractures in the T2 spectrum were considered for correction, and a direct relationship between the permeability, F-T temperature and number of cycles was obtained via regression analysis. Compared to the experimental results, it was found that the modified model achieved a good applicability. The damage and permeability characteristics of shale under different F-T conditions were analysed from a microscopic perspective, which could yield an important reference for engineering construction in frozen soil areas.

Experimental Study on the Evolution Trend of the Pore Structure and the Permeability of Coal under Cyclic Loading and Unloading.

In the deep mining process of coal seams, the mechanical environment of the coal body is complex and in the state of cyclic loading and unloading. The change in the stress state leads to the change in the pore characteristics and the permeability. To investigate the effects of cyclic loading and unloading on the pore characteristics and the permeability of coal, the seepage experiment was carried out for the coal samples using the self-developed triaxial permeation instrument. By pressure confining and continuous cyclic loading and unloading, the evolution of the porosity and the permeability of the coal samples was investigated. Under the condition of the experiment, the influences of the initial value of the confining pressure and the cyclic load amplitude on the evolution of the permeability and the pore structure characteristics of the coal samples were clarified. The experimental results showed that the porosity and the permeability decreased exponentially with an increase in the number of loading and unloading cycles, and this decreasing trend gradually weakened until the porosity and the permeability became relatively stable. When the cyclic load amplitude was the same and the confining pressure increased, the effective porosity of the coal body and the bound porosity decreased. When the confining pressure was the same and the cyclic load amplitude increased, the effective porosity of the coal body decreased and the bound porosity increased. The loss rate of the permeability of the coal samples increased gradually with an increase in the cyclic load amplitude. The same tendency was observed when the cyclic load amplitude was the same, and the confining pressure was different, while the increasing trend was not so obvious. By analyzing the relationship between the porosity and the permeability of the coal samples under different cyclic loading and unloading paths, it was found that the effective porosity and the permeability of the coal samples conformed to the power-law relationship in the process of cyclic loading and unloading, and the change in the cyclic load amplitude had a significant effect on this relationship. The influences of the cyclic load amplitude and the confining pressure on the stress sensitivity of the coal samples were considered, and the change factor of the stress sensitivity was introduced into the relationship between the porosity and the permeability. This relationship was established considering cyclic loading and unloading.

Uptake and concentration of heavy metals in dominant mangrove species from Hainan Island, South China.

By investigating three dominant mangrove species, namely Aegiceras corniculatum, Kandelia candel, Ceriops tagal and their rhizosediment in Mangrove wetlands in Hainan Island, this research analyzed absorption, concentration and distribution of heavy metals (Cr, Cu, Zn, As, Cd and Pb) in mangroves. The results found that the concentration of specific heavy metal differs in the different mangrove organs (leaf, stem and root). The content of heavy metals concentrated greatly in roots, but less in leaves and stems. The study also revealed that concentration capacity was weak in all three mangrove species (BCF0.02-0.91), with their organ ranking BCFroot > BCFstem > BCFleaf. Among three mangrove species, the transfer factors of leaves and stems in Ceriops tagal were highest, indicating a great distribution capability for heavy metals, followed by Kandelia candel. Transfer factors in Aegiceras corniculatum were the weakest. This ranking was opposite to bioconcentration factors of roots. This study can further reflect bioavailability of heavy metals in sediments, which provides scientific evidence on ecosystem protection and management in mangrove wetlands.

Mudstone creep experiment and nonlinear damage model study under cyclic disturbance load.

To study the creep characteristics of mudstone under disturbed load, creep rock triaxial compression disturbance tests under different disturbance amplitudes and frequencies are conducted using a self-made triaxial disturbed creep test bench for rock. The influence of different factors on the creep deformation law of each stage is analyzed. The results show that the disturbance effect has a significant impact on the creep properties of mudstone, and various factors have different effects on the creep stages. The instantaneous deformation variable, creep decay time, and steady creep rate change exponentially with the increase in axial pressure, and increase linearly with the increase in disturbance amplitude and disturbance frequency. The disturbance amplitude has a more significant effect on the instantaneous deformation, steady-state creep rate, and accelerated creep. According to the analysis of the test results, a nonlinear disturbance creep damage model based on Burger's model is established. The model is identified and calculated by the improved least squares method based on pattern search. The influence of different disturbance factors on the creep parameters is analyzed. The model fitting results and experimental results are compared to demonstrate that the model is used to simulate different disturbances. It was observed that rock creep under certain conditions exhibits certain adaptability. It is of great significance to carry out rock disturbance creep experiments and study the theory of disturbance creep to ensure the long-term stability of deep rock mass in complex environment.

Effects of soil type and rainfall intensity on sheet erosion processes and sediment characteristics along the climatic gradient in central-south China.

Soil erosion poses a major threat to the sustainability of natural ecosystems. The main objective of this study was to investigate the effects of soil type and rainfall intensity on sheet erosion processes (hydrological, erosional processes and sediment characteristics) from temperate to tropical climate. Field plot experiments were conducted under pre-wetted bare fallow condition for five soil types (two Luvisols, an Alisol, an Acrisol and a Ferralsol) with heavy textures (silty clay loam, silty clay and clay) derived separately from loess deposits, quaternary red clays and basalt in central-south China. Rainfall simulations were performed at two rainfall intensities (45 and 90mmh-1) and lasted one hour after runoff generation. Runoff coefficient, sediment concentration, sediment yield rate and sediment effective size distribution were determined at 3-min intervals. Runoff temporal variations were similar at the high rainfall intensity, but exhibited a remarkable difference at the low rainfall intensity among soil types except for tropical Ferralsol. Illite was positively correlated with runoff coefficient (p<0.05). Rainfall intensity significantly contributed to the erosional process (p<0.001). Sediment concentration and yield rate were the smallest for the tropical Ferralsol and sediment concentration was the largest for the temperate Luvisol. The regimes (transport and detachment) limiting erosion varied under the interaction of rainfall characteristics (intensity and duration) and soil types, with amorphous iron oxides and bulk density jointly enhancing soil resistance to erosive forces (Adj-R2>88%, p<0.001). Sediment size was dominated by <0.1mm size fraction for the Luvisols and bimodally distributed with the peaks at <0.1mm and 1-0.5mm size for the other soil types. Exchangeable sodium decreased sediment size while rainfall intensity and clay content increased it (Adj-R2=96%, p<0.01). These results allow to better understand the climate effect on erosion processes at the spatial-temporal scale from the perspective of soil properties.