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Objective In the geological survey for Guiyang urban rail transit projects, karst is a common unfavorable geological condition and also the top geological issue to be confronted. However, the current survey mode of karst problems does not match the demand of Guiyang urban rail transit construction. Therefore, it is necessary to explore a karst survey mode applicable for urban rail transit construction in karst mountainous city. Method Starting from the karst hazards, the technical means, normative constrains and the actual experience from Guiyang City about karst survey are summarized and analyzed. It is then clearly pointed out that the current karst survey mode with “engineering geological mapping first, engineering drilling as the main method, engineering geophysical prospecting as the secondary method” is formed in the course of history, the situation where the contradiction between high resolution requirements and low resolution levels of the karst survey method becomes the principal one in current mountain karst survey for rail transit is discussed. Result & Conclusion Starting from the main contradiction in the current karst survey, and based on the development of technical means in karst survey and specific case analysis, it is concluded through research that the above-mentioned karst survey mode will inevitably evolve into a new survey mode of “starting from engineering needs and guided by geological thinking, with geological mapping first, ground geophysical survey, drilling and borehole geophysical prospecting as supplement and verification, featuring multi-method integration”.

Silica aerogels are widely used in many fields for thermal insulation, such as building insulation, electric power energy, energy storage systems, and high-temperature thermal protection due to their excellent insulation performance. Therefore, the heat transfer in silica aerogels and its modeling in recent years have attracted much attention and many valuable achievements have been acquired. The heat transfer in nano-porous silica aerogels and its modeling methods are reviewed in this work. This review starts with a brief introduction of heat transfer characteristics in silica aerogels, including the multi-component and multi-mode coupling effect, size effect, and multiscale effect. Then the heat transfer mechanism of each mode, including heat transfer via gas phase, solid phase, and thermal radiation, is reviewed, and the models for predicting the gaseous thermal conductivity in nanoscale pores, gas-contributed thermal conductivity, the apparent thermal conductivity of solid skeleton, and finally the effective thermal conductivity are collected and discussed in details. Besides, modeling of transient heat transfer in silica aerogels is also briefly introduced. Finally, the conclusions and some problems which need to be further investigated in the future are provided.

Abstract Background In hepatocellular carcinoma (HCC), pulmonary metastasis (PM) after hepatectomy is associated with poor clinical outcomes. The crucial phases of tumour cell proliferation, angiogenesis, and metastasis all entail platelet activation. In HCC, platelet distribution width (PDW) suggests platelet size changes and predicts a worse prognosis. The aim of this study was to assess the association between PDW and PMs in HCC patients receiving hepatectomy. Material/methods From January 2013 to December 2015, a cohort of patients who underwent hepatectomy for HCC at the Harbin Medical University Cancer Hospital in China were retrospectively evaluated. The relationship between PDW levels and clinical and demographic parameters was examined. To investigate the relationships between predicted factors and PM, a competing risk model was used. From January 2016 to December 2018, a validation cohort of 109 patients from the First Affiliated Hospital of Harbin Medical University was studied independently. Results In the primary cohort, 19 out of 214 patients had postoperative PMs. In HCC patients with PM, PDW levels were lower than in those without PM. There was a significant difference in the cumulative incidence of 2-year PM between the high-PDW and low-PDW groups after controlling for competing risk events (death prior to the development of PM) (p

Abstract Background Intrahepatic cholangiocarcinoma (ICC) and hepatocellular carcinoma (HCC) are the most prevalent histologic types of primary liver cancer. HCC and ICC differ in treatment and prognosis, warranting an effective differential diagnosis between them. This study aimed to explore the clinical value of mean platelet volume (MPV) to discriminate between HCC and ICC. Material/methods We performed a retrospective analysis of ICC and HCC patients who were from the Harbin Medical University Cancer Hospital, China. Logistic regression analysis was used to identify the independent factors for the differentiation of HCC and ICC. A receiver operating characteristic curve was built to evaluate the diagnostic performance of the potential model. An independent validation study was performed to validate the diagnostic ability. Results ICC patients were detected in 146 out of 348 patients in the primary cohort. MPV levels were decreased in ICC patients compared with those in HCC patients. Logistic regression analysis revealed that MPV was an independent factor in distinguishing HCC from ICC. A combination of sex, hepatitis B surface antigen, MPV, alpha-fetoprotein, and carbohydrate antigen 19–9 demonstrated a good capability to differentiate HCC from ICC. Similar results were achieved in the validation cohort. Conclusions MPV may be a new marker to help distinguish ICC from HCC. Further validation studies are required.

Charring composites can provide the most efficient thermal protection shield for the thermal protection system (TPS), which is essential for hypersonic reentry vehicles. It is of great importance to clarify the implication of different porosity configurations of charring composite on the bondline temperature. In the present study, a one-dimensional transient thermal model considering the pyrolysis without the surface recession is built and validated. Based on this model, the thermal protection performance of various porosity distribution design schemes is analyzed when keeping the total pore volume unchanged. The present results show that the scheme with the linear increasing porosity from the bondline to the heated surface can decrease the bondline temperature by 7.8 K and 15.8 K compared with the homogeneous scheme and the linear decreasing scheme, respectively. Further, a scheme with parabolic increasing distribution of porosity are evaluated. It is found that it can reduce the bondline temperature by an additional 2.9 K.