Resistant dextrin protects against pathological bone loss in ovariectomized rats and inhibits RANKL-induced osteoclastogenesis

Background. Osteoporosis is a common disease in postmenopausal women characterized by systemic bone mass loss, microstructure fragility and increased incidence of fractures. Resistant dextrin (RD) is a soluble fiber with beneficial metabolic effects. However, the beneficial effect of RD in osteoporosis remains to be determined. Methods. In this study, we investigated the effect of dietary RD supplement on osteoporosis in ovariectomized (OVX) rats. Both the control (sham) and OVX group rats were gavaged with RD (10 g/kg/d) or equal amount of saline for 12 weeks, and histological and biomechanical analyses were conducted to evaluate bone microstructure and strength. Furthermore, we also evaluated the effects of RD on osteoclastogenesis in bone marrow macrophages (BMMs) by detecting the expression of osteoclast-related genes using qRT-PCR and Western blot analysis. Results. The results showed that in OVX rats the bone strength and microstructure characteristics were significantly improved with RD supplement for 12 weeks. Additionally, the mRNA and protein expression of osteoclast markers, such as CTSK, NF-κB and NFATC1, were significantly down-regulated in BMMs isolated from RD supplement group. RD also suppressed RANKL-induced osteoclastogenesis in BMMs. Conclusion. These findings suggest that RD ameliorates osteoporosis in OVX rats by inhibiting osteoclast differentiation. RD suppresses RANKLinduced osteoclastogenesis possibly through modulating Akt and NF-κB signaling pathways. These data indicate that a dietary supplement of RD might serve as an intervention strategy for menopausal osteoporosi

Environmental Stress Testing for China’s Overseas Coal Power Investment Project

The advance of the Chinese “Belt and Road” initiative encourages increased overseas investment in coal power projects. However, it also brings about external environmental risks. In this paper, we use the approach of environmental stress testing to examine China’s overseas coal power investment projects by focusing on two countries: Indonesia and Vietnam. We first identify five key testing factors (i.e., coal price, utilization hours, exchange rate, carbon tax, and environmental protection requirements) by examining the market regulation and the environmental risks of coal power projects along the “Belt and Road” countries. Then, we observed changes in the enterprise value and internal rate of return (IRR) by setting different scenarios in which the values of the five stress factors varied. The results show that (1) the economics of coal-fired projects in Indonesia is most sensitive to exchange rate, while the economics of coal projects in Vietnam is most sensitive to coal price; (2) the pressure of nationally determined contributions (NDC) goals on environmental protection will push the “Belt and Road” countries to implement more stringent environmental regulation, which will reinforce environmental stress on overseas coal power investment. These results have important policy implications for the enterprise, industry, and Chinese government

Study on Evolution of Front Abutment Pressure at Working Face in Repeated Mining of Close-Distance Coal Seams

In order to determine the reasonable width of a stopping coal pillar in close-distance coal seams, the evolution law of front abutment pressure of the working face with repeated mining was studied. Based on the actual engineering project, we conducted field measurement, theoretical analyses, numerical simulations and a physical similarity simulation test to study. The results show that: (1) according to field measurement, the influence range of front abutment pressure increases from 60 m to 75 m with repeated mining; (2) according to theoretical analysis, the arch height and span are negatively and positively correlated with the influence range of front abutment pressure, respectively; (3) with repeated mining, the arch height increased to 165 m, the arch span to 235 m and the influence range to 83.5 m by 14.5 m relative to that before repeated mining; (4) if it is necessary to ensure that the main roadway is less affected by the mining stress, the width of the stopping coal pillar in 2214 working face should be greater than 80 m. The influence range of front abutment pressure increases obviously with repeated mining in close-distance coal seams. The study provides a reference for similar engineering projects

Study on Evolution of Front Abutment Pressure at Working Face in Repeated Mining of Close-Distance Coal Seams

In order to determine the reasonable width of a stopping coal pillar in close-distance coal seams, the evolution law of front abutment pressure of the working face with repeated mining was studied. Based on the actual engineering project, we conducted field measurement, theoretical analyses, numerical simulations and a physical similarity simulation test to study. The results show that: (1) according to field measurement, the influence range of front abutment pressure increases from 60 m to 75 m with repeated mining; (2) according to theoretical analysis, the arch height and span are negatively and positively correlated with the influence range of front abutment pressure, respectively; (3) with repeated mining, the arch height increased to 165 m, the arch span to 235 m and the influence range to 83.5 m by 14.5 m relative to that before repeated mining; (4) if it is necessary to ensure that the main roadway is less affected by the mining stress, the width of the stopping coal pillar in 2214 working face should be greater than 80 m. The influence range of front abutment pressure increases obviously with repeated mining in close-distance coal seams. The study provides a reference for similar engineering projects

Deviatoric Stress Evolution Laws and Control in Surrounding Rock of Soft Coal and Soft Roof Roadway under Intense Mining Conditions

Aiming at the problem of large deformation and instability failure and its control of soft coal and soft roof roadway under intense mining, laboratory experiments, theoretical calculations, Flac3D numerical simulation, borehole peeping, and pressure observation were used to study the deflection characteristics of the deviatoric stress of the gas tailgate and the distribution and failure characteristics of the plastic zone in the mining face considering the strain softening characteristics of the roof and coal of roadway, and then the truss anchor cable-control technology is proposed. The results show the following: (1) The intense mining influence on the working face will deflect the peak deviatoric stress zone (PDSZ) of the surrounding rock of the gas tailgate. The influence distance of PDSZ is about 20 m in advance and 60 m in lag; the PDSZ at the gob side of the roadway is located in the range of 3–5.5 m from the surface of the coal pillar, while the coal wall side is mainly located in the range of 3–4.5 m at the shoulder corner and bottom corner of the solid coal. (2) The intense mining in the working face caused the nonuniform expansion of the surrounding rock plastic area of the gas tailgate. The two shoulder angles of the roadway and the bottom of the coal pillar have the largest damage range, and the maximum damage location is the side angle of the coal pillar (5 m). Angle and bottom angle of coal pillar are the key points of support control. (3) The plastic failure line of the surrounding rock of the gas tailgate is always between the inner and outer contours of the PDSZ, and the rock mass in the PDSZ is in a stable and unstable transition state, so the range of anchor cable support should be cross plastic failure line. (4) The theoretical calculations and numerical simulation results agree well with the drilling peep results. Based on the deflection law of the PDSZ and the expansion characteristics of the plastic zone, a truss anchor cable supporting system with integrated locking and large-scale support function is proposed to jointly control the roof and the two sides, which effectively solves the problem of weak surrounding rock roadway under severe mining deformation control problems realizing safety and efficient production in coal mines under intense mining

Chinese mothers’ intention to vaccinate daughters against human papillomavirus (HPV), and their vaccine preferences: a study in Fujian Province

Little is known regarding Chinese mothers’ intention to vaccinate their daughters against human papillomavirus (HPV) since the HPV vaccine was approved for use in China in 2016. The aim was to explore maternal HPV vaccination acceptance, preference for 2-, 4- or 9-valent HPV vaccine and acceptance of domestically manufactured HPV vaccines. Study participants were mothers of primary school children in Southeastern region of Fujian. An online cross-sectional survey was undertaken between June and August 2019. Among the total of 3,586 completed responses (response rate 28.5%), the intention to vaccinate daughter against HPV was high (83.3%). Higher maternal education and perceived benefit and barriers were associated with greater intention to vaccinate. Among mothers who did not intend to vaccinate their daughters, the three most common reasons were daughter being too young to receive HPV vaccination (40.6%), fear of side effects (31.9%) and vaccine price is too high (16.0%). The largest proportion (41.4%) preferred their daughter to be vaccinated with the 9-valent HPV vaccine (9vHPV). Greater preference for 9vHPVwas strongly associated with higher maternal education level and annual household income. The majority of mothers expressed a preference for imported HPV vaccine (56.3%). Our result indicates that lower intentions to vaccinate daughters against HPV among less educated and lower-income mothers may lead to significant social inequalities in HPV vaccine uptake in the country

Roadway Surrounding Rock under Multi-Coal-Seam Mining: Deviatoric Stress Evolution and Control Technology

Multi-coal-seam mining creates surrounding rock control difficulties, because the mining of a coal face in one seam can affect coal faces in another. We examine the effects of multi-coal-seam mining on the evolution of the deviatoric stress distribution and plastic zone in the roadway surrounding rock. In particular, we use numerical simulation, theoretical calculation, drilling detection, and mine pressure observation to study the distribution and evolution characteristics of deviatoric stress on Tailgate 8709 in No. 11 coal seam in Jinhuagong mine when the N8707 and N8709 coal faces in No. 7-4 coal seam and the N8707 and N8709 coal faces in No. 11 coal seam are mined. The evolution laws of deviatoric stress and the plastic zone of roadway surrounding rock in the advance and behind sections of the coal face are studied, and a corresponding control technology is proposed. The results show that the peak value of deviatoric stress increases with the advance of the coal face, and the positions of the peak value of deviatoric stress and the plastic zone become deeper. The deflection angle of the peak stress after mining at each coal face and the characteristics of the peak zone of deviatoric stress and the plastic zone of the roadway surrounding rock under the disturbance of multi-coal-seam mining are determined. In conclusion, the damage range in the roadway roof in the solid-coal side and coal pillar is large and must be controlled. A combined support technology based on high-strength and high pretension anchor cables and truss anchor cables is proposed; long anchor cables are used to strengthen the support of the roadway roof in the solid-coal side and coal pillar. The accuracy of the calculated plastic zone range and the reliability of the combined support technology are verified through drilling detection and mine pressure observation on site. This research can provide a point of reference for roadway surrounding rock control under similar conditions

Chinese mothers’ intention to vaccinate daughters against human papillomavirus (HPV), and their vaccine preferences: a study in Fujian Province

Little is known regarding Chinese mothers’ intention to vaccinate their daughters against human papillomavirus (HPV) since the HPV vaccine was approved for use in China in 2016. The aim was to explore maternal HPV vaccination acceptance, preference for 2-, 4- or 9-valent HPV vaccine and acceptance of domestically manufactured HPV vaccines. Study participants were mothers of primary school children in Southeastern region of Fujian. An online cross-sectional survey was undertaken between June and August 2019. Among the total of 3,586 completed responses (response rate 28.5%), the intention to vaccinate daughter against HPV was high (83.3%). Higher maternal education and perceived benefit and barriers were associated with greater intention to vaccinate. Among mothers who did not intend to vaccinate their daughters, the three most common reasons were daughter being too young to receive HPV vaccination (40.6%), fear of side effects (31.9%) and vaccine price is too high (16.0%). The largest proportion (41.4%) preferred their daughter to be vaccinated with the 9-valent HPV vaccine (9vHPV). Greater preference for 9vHPVwas strongly associated with higher maternal education level and annual household income. The majority of mothers expressed a preference for imported HPV vaccine (56.3%). Our result indicates that lower intentions to vaccinate daughters against HPV among less educated and lower-income mothers may lead to significant social inequalities in HPV vaccine uptake in the country

Study on Stability and Control of Surrounding Rock in the Stopping Space with Fully Mechanized Top Coal Caving under Goaf

Under the condition of fully mechanized top coal caving in close-distance coal seams, the surrounding rock of the stopping space easily loses stability during the withdrawal of mining equipment in the working face because the lower coal seam working face is located under the goaf and the overburden rock has a large range of complex interaction. Field investigation, theoretical analysis, laboratory experiment, similar simulation experiment, numerical simulation, and field industrial tests are used to carry out the research on the stability and control of the surrounding rock in the large section stopping space under the goaf in this paper. The research conclusions are as follows. (1) It is determined that the lower coal seam working face can only stop mining under the goaf, and the reasonable stopping position under the goaf should ensure that the key block fracture line of the main roof is behind the support. (2) The interaction law between the main roof’s key blocks of the upper and lower coal seams is analyzed, and the catastrophic conditions for sliding instability and rotary instability of the main roof’s key blocks of the upper and lower coal seams are obtained. (3) “Anchorage with push and pull equipment-Embedded anchorages and trays” integral anchoring technology is developed. The dimensions of the push and pull equipment are determined. (4) Through numerical simulation of the distribution characteristics of the anchor cable pre-stress field, the asymmetric control scheme of “Partition long and short anchor cables + Integral polyurethane mesh + Embedded anchorages and trays for roof protection” is determined. The rock pressure observation shows that the withdrawal of the working face equipment is implemented safely