Primary breast angiosarcoma: A case report.

RATIONALE: Primary breast angiosarcoma is a rare tumor, accounting for only 0.05% of all malignant breast tumors. The primary breast angiosarcoma typically presents with nonspecific clinical manifestations, which can easily lead to misdiagnosis. Potential factors contributing to misdiagnosis include skin changes that may be erroneously attributed to breast trauma-induced bruising and breast swelling that may be mistaken for inflammatory diseases or other benign tumors. PATIENT CONCERNS: A 19-year-old female was admitted to the hospital due to repeated lump formation in the left breast for 9 months after left breast trauma. DIAGNOSES: The diagnosis of primary breast angiosarcoma was confirmed on hematoma biopsy. INTERVENTIONS: Due to the patient's condition, no special treatment was given postoperatively. After then, there was a recurrence in the chest wall, and the patient received 2 cycles of chemotherapy, resulting in a reduction in the size and lightening of the recurrent chest wall mass. When chemotherapy intolerance happened, the patient chose to discontinue treatment. OUTCOMES: After an 18-month follow-up, the recurrent chest wall mass increased and the patient died from bleeding. LESSONS: Primary breast angiosarcoma has a low incidence but high malignancy, with a high recurrence and metastasis rate, leading to a poor prognosis. The adjuvant chemotherapy, radiotherapy, targeted therapy, and other treatments should be considered to reduce the local recurrence rate and prolong patient survival.

An innovative destressing technology and key parameters determination in both sides of a deep roadway.

The general or single supporting theory and technology of the shallow surrounding rock of the roadway are not suitable for solving the problem of continuous large deformation of the both sides under the continuous migration of coal mass in the deep domain of the roadway side. Furthermore, the general destressing technology of dense drilling in the roadway destroys the shallow anchorage domain while releasing the stress. Therefore, this study proposes the "shallow supporting and deep destressing" synergism technology. This technology provides puissant supporting in the shallow domain of roadway sides, and at the same time, large destressing holes are excavated at the coal mass migration channel in deep stress peak domain far from the anchorage domain, conducting destressing regulation of roadway sides. This technology can shift stress peak domain of the roadway side to solid coal side of destressing hole without destroying the shallow anchorage domain, and at the same time, provide a buffer space for that coal mass in the deep domain of the roadway side continuously migrates to the anchorage surrounding rock, creating a beneficial stress circumstances for the roadway stability. The "shallow supporting and deep destressing" synergism technology can solve the contradiction between the shallow surrounding rock supporting and the continuous migration of coal mass in deep domain. The field application results show that the innovative destressing technology can effectively solve the problem of surrounding rock control in deep roadway.

Study on the Effect of Strain-Softening on Permeability and Gas Pressure in Surrounding Rocks of a Hydraulic Flushing Borehole.

Hydraulic flushing gas extraction technology is gradually being applied in coal mines because it can effectively improve the gas extraction efficiency. This study aimed to explore the effect of strain-softening on permeability and gas pressure, due to the deficiency of previous studies on hydraulic flushing that did not consider the strain-softening of surrounding rocks. First, we analyzed the essence of strain-softening based on previous studies and proved the existence of strain-softening in surrounding rocks of the hydraulic flushing borehole by a field example. Subsequently, we established gas extraction models for different borehole diameters with and without considering strain-softening through the permeability evolution equation, the gas migration equation, and the strain-softening equation. We found that strain-softening significantly effects the permeability and gas pressure of the surrounding rocks of the borehole: the larger the diameter, the greater the effect on strain-softening. Compared with strain-softening not considered, the permeability, the permeability increase range, and the gas extraction standard range in surrounding rocks of hydraulic flushing boreholes will increase under the same borehole diameter when strain-softening is considered. The borehole diameter increases from 0.113 to 0.7 m, and the increases in permeability are 592.76 × 10-12, 614.25 × 10-12, 615.13 × 10-12, and 655.29 × 10-12 m2, respectively, the increases in permeability increase radius are 0.050, 0.121, 0.193, and 0.255 m, respectively, and the increase in gas extraction standard range radius under the two indicators are 0.119, 0.124, 0.190, 0.253 m and 0.052, 0.102, 0.150, 0.191 m, respectively. The gas pressure distribution in surrounding rocks of the borehole will also be changed by considering strain-softening, resulting in a slowly increasing gas pressure zone near the borehole: the larger the diameter, the greater the zone. Our research results proved that it is necessary to consider the strain-softening of surrounding rocks when studying gas extraction through hydraulic flushing boreholes. Moreover, we provide a novel explanation for the mechanism of gas extraction through hydraulic flushing boreholes based on the study's results. The finding of this study can help better understand the mechanism of enhanced gas extraction through hydraulic flushing boreholes.

Stability analysis and control technology of the sump-surrounding rock under a 1200-m-deep goaf: a case study.

In this study, a sump in the Xingdong coal mine (buried at a depth of over 1200 m) was used to analyze the surrounding rock's stability and control technology. Under the combined influences of various complex conditions, such as the burial depth of over 1200 m, ultra-high ground stress, and location under the goaf, the sump support became extremely difficult, severely restricting the efficient production of the mine. The overall pressure-relief mechanisms and degree of the sump surrounding the rock environment under the goaf were studied, and the rationality of the sump location was verified through numerical simulations and field tests. A more effective support scheme was proposed based on the deformation characteristics and failure mechanisms of the temporary sump-surrounding rock under the supporting conditions. The combined control technology employed the lengthened strong anchor bolts (cables), full-section concrete-filled steel tubular supports, and pouring full-section reinforced concrete and full-section long-hole grouting reinforcement. The field test results showed that after adopting the new support scheme, the sump-surrounding rock tended to be stable after three months. The sump roof subsidence amount, floor heave amount, and convergence of the two sidewalls of the sump were 17.2-19.2 mm, 13.9-16.5 mm, and 23.2-27.9 mm, respectively, thus satisfying the application requirements. This study provides an essential reference for deep-mine roadway support under a complex high-ground-stress environment.

The J2 evolution model and control technology of the main roadway surrounding rock under superimposed influence of double-coal seam mining.

Under double-seam mining, the main roadway surrounding rock is affected by the superposition of the advanced stress of the two-seam coal working faces. The stress superposition mode and degree are of great significance to the width calculation of the protective coal pillar and the determination of the critical control direction of the surrounding rock. This paper uses theoretical analysis, numerical simulation, and site engineering practice to carry out targeted research. The conclusions are as follows: Under different lateral pressure coefficients, the superposition evolution law of maximum principal stress direction of two coal seams with different offsets; Two developmental trends and three types of evolution models of J2 peak zone (the critical area of the stress increase and deflection changes) under different superimposed loading modes are summarized. Based on the typical asymmetric evolution model of the J2 peak zone, an asymmetric truss-cable co-anchoring method is proposed aimed at the J2 critical zone. The field monitoring results show that the main roadway surrounding rock is stable after support when the upper coal seam protective coal pillar is left 80 m, and the lower one is 60 m wide. It is of great reference importance for similar engineering practices.

[Effects of different puncture levels in bilateral percutaneous vertebroplasty on distribution of bone cement and effectiveness of osteoporotic thoracolumbar compression fractures].

Objective: To investigate the effects of different puncture levels on bone cement distribution and effectiveness in bilateral percutaneous vertebroplasty for osteoporotic thoracolumbar compression fractures. Methods: A clinical data of 274 patients with osteoporotic thoracolumbar compression fractures who met the selection criteria between December 2017 and December 2020 was retrospectively analyzed. All patients underwent bilateral percutaneous vertebroplasty. During operation, the final position of the puncture needle tip reached was observed by C-arm X-ray machine. And 118 cases of bilateral puncture needle tips were at the same level (group A); 156 cases of bilateral puncture needle tips were at different levels (group B), of which 87 cases were at the upper 1/3 layer and the lower 1/3 layer respectively (group B1), and 69 cases were at the adjacent levels (group B2). There was no significant difference in gender, age, fracture segment, degree of osteoporosis, disease duration, and preoperative visual analogue scale (VAS) score, and Oswestry disability index (ODI) between groups A and B and among groups A, B1, and B2 ( P>0.05). The operation time, bone cement injection volume, postoperative VAS score, ODI, and bone cement distribution were compared among the groups. Results: All operations were successfully completed without pulmonary embolism, needle tract infection, or nerve compression caused by bone cement leakage. There was no significant difference in operation time and bone cement injection volume between groups A and B or among groups A, B1, and B2 ( P>0.05). All patients were followed up 3-32 months, with an average of 7.8 months. There was no significant difference in follow-up time between groups A and B and among groups A, B1, and B2 ( P>0.05). At 3 days after operation and last follow-up, VAS score and ODI were significantly lower in group B than in group A ( P<0.05), in groups B1 and B2 than in group A ( P<0.05), and in group B1 than in group B2 ( P<0.05). Imaging review showed that the distribution of bone cement in the coronal midline of injured vertebrae was significantly better in group B than in group A ( P<0.05), in groups B1 and B2 than in group A ( P<0.05), and in group B1 than in group B2 ( P<0.05). In group A, 7 cases had postoperative vertebral collapse and 8 cases had other vertebral fractures. In group B, only 1 case had postoperative vertebral collapse during follow-up. Conclusion: Bilateral percutaneous vertebroplasty in the treatment of osteoporotic thoracolumbar compression fractures can obtain good bone cement distribution and effectiveness when the puncture needle tips locate at different levels during operation. When the puncture needle tips locate at the upper 1/3 layer and the lower 1/3 layer of the vertebral body, respectively, the puncture sites are closer to the upper and lower endplates, and the injected bone cement is easier to connect with the upper and lower endplates.

Technology and engineering test of filling goaf with coal gangue slurry.

Based on the greening and low interference disposal requirements of coal gangue in high-yield and high-efficiency mines in Inner Mongolia and Shaanxi, and by integrating the existing theories and technologies such as underground filling technology of coal gangue, mine yellow mud grouting technology, and the evolution law of mining overburden fractures, a technology of filling goaf with coal gangue slurry for green disposal of coal gangue is proposed. The principle and technical framework of the technology of filling goaf with coal gangue slurry are clarified. This paper expounds on the technological process of technology of filling goaf with coal gangue slurry, establishes three types of slurry filling systems, such as centralized ground layout, ground and underground coordinated layout, and centralized underground layout, and constructs three slurry filling methods, including low-level grouting, adjacent level grouting, and high-level grouting, forming seven kinds of technology models of filling goaf with coal gangue slurry, including ground centralized pulping + high-level grouting, ground centralized pulping + adjacent grouting, ground centralized pulping + low level grouting, ground and underground coordinated pulping + adjacent grouting, ground and underground coordinated pulping + low level grouting, underground centralized pulping + adjacent grouting, and underground centralized pulping + low level grouting, and gives the selection process of technology models of filling goaf with coal gangue slurry. Based on the different conditions and requirements of Haidaze Coal Mine and Huangling No. 2 Coal Mine, engineering tests were carried out on two different technology modes, namely, ground and underground coordinated pulping + low level grouting and ground and underground coordinated pulping + adjacent grouting, based on simulation tests of low level grouting and adjacent grouting. The tests prove the feasibility of filling goaf with coal gangue slurry and explore the way for the theoretical research of the technology of filling goaf with coal gangue slurry and greening and low interference disposal of coal gangue.

Influence of the ultra-fine fly ash dosages on the mechanical properties of the sulfoaluminate cement-based high water backfilling material.

To reduce the filling cost of high-water backfilling material (HWBM) in mining backfill and improve the recycling utilization of the industrial waste such as the coal fly ash. The ultra-fine fly ash (UFA) was added to the HWBM as a partial replacement in this work. Therefore, a series of experiments were performed to investigate the effect of UFA on the mechanical properties of the HWBM at the different curing conditions, then the hydration mechanism of the HWBM blended with UFA was analyzed by XRD and SEM method. The result indicates that the strength of the HWBM decreased with the increasing of UFA dosages, but the addition of UFA can improve the residual strength of the initial HWBM. Additionally, when the HWBM was cured at the laboratory air condition, its carbonation process was restrained obviously as the UFA dosages were less than 15% at the ages of 28 days, which indicates the UFA can improve the weathering resistance of the HWBM with the curing ages increasing effectively. The XRD and SEM results also shows that the degree of crystallinity of the HWBM increased when UFA dosages were less than 15% effectively, while there were few obvious changes on types of hydration products. It indicates that the main affects of UFA on the performance of HWBM is filler and dilution, which reduced the contact area between hydration products of HWBM and CO2 in the air, further improved the carbonation resistance of HWBM.

Experimental and mechanistic research on modifying the mechanic properties of the high water backfill material by electrochemical treatment.

To promote the engineering applications of high water backfill materials (HWBM) in mining, a series of experiments are performed to investigate the effects of the direct current (DC) electric field on the mechanic properties and electrical resistivity of HWBMs. Based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) investigations, the influence of electrochemical treatment on the hydration products and the microstructure of the HWBM was studied. The results show that the peak strength, elastic modulus, deformation modulus and electrical resistivity of the HWBM samples all first increased and then decreased with the increasing of the potential gradient, and the peak points appeared when the potential gradient was 0.2 V/cm. The anisotropy of content of ettringite and calcium silicate hydrates (C-S-H) increased betweent the anodic and cathodic regions of samples. Meanwhile, microstructure in the anodic region of the samples was more stable after electrochemical treatment, which indicates that the different variation of mineralogical compositions and microstructures in different regions of the samples are the primary factors affecting the mechanic properties and electrical resistivity of the HWBM. Therefore, the electrochemical method is a potential technology to modify the engineering properties of the HWBM.