坚硬顶板切顶卸压围岩变形规律研究

为了进一步揭示坚硬顶板超前切顶卸压轨道下山的变形规律和保安煤柱的应力分布特征,以潞宁煤矿22115工作面开采为工程背景,利用相似材料模拟和现场实验,分析了坚硬顶板切顶轨道下山变形规律。结果表明:切顶可使采空区坚硬顶板在剪应力作用下沿着预制裂隙垮落,缩短悬顶长度,切断应力传递途径,有效缓解了保安煤柱承担的载荷。现场实践效果较好,巷道顶底板移近量约为320 mm,两帮移近量约为245 mm;切顶卸压技术是高应力坚硬顶板大变形巷道围岩控制有效途径之一。     

Magnesium facilitates the healing of atypical femoral fractures: A single-cell transcriptomic study

Bisphosphonates (BPs)-associated atypical femoral fractures (AFFs) present with impaired fracture healing, yet the underlying mechanism is unclear, which prevents the development of effective therapy. Peripheral sensory nerve has been shown to regulate fracture healing via releasing neuropeptides. Here we show that long-term BPs pre-treatment leads to fracture non-union in rats, characterized by reduced expression of calcitonin gene-related peptide (CGRP, a predominant type of neuropeptides) and abundant fibrous tissues in the non-bridged fracture gap, mimicking clinical AFFs. By using single-cell RNA-sequencing, long-term BPs treatment was identified to promote transition of progenitor cells into a specific cluster of fibroblasts that actively deposit dense extracellular matrix (ECM) to prevent fracture callus bridging. Administration of exogenous CGRP at early stages of fracture repair, in contrast, eliminates the ECM-secreting fibroblast cluster, attenuates fibrogenesis, and facilitates callus bridging, suggesting CGRP is a promising agent to facilitate AFF healing. Accordingly, we have developed an innovative magnesium (Mg) containing hybrid intramedullary nail fixation system (Mg-IMN) to effectively rescue BPs-impaired fracture healing via elevating CGRP synthesis and release. Such device optimizes the fracture healing in BPs-pretreated rats, comparable to direct administration of CGRP. These findings address the indispensable role of CGRP in advancing the healing of AFFs and develop translational strategies to accelerate AFF healing by taking advantage of the CGRP-stimulating effect of Mg-based biodegradable orthopedic implant. The study also indicates fibrosis could be targeted by augmenting CGRP expression to accelerate fracture healing even under challenging scenarios where fibroblasts are aberrantly activated.     

渗流对坚硬复合岩体巷道环境断裂失稳影响分析

本文在借鉴孔隙介质渗流过程的细观实验与理论研究的基础上 ,从宏观上分析了渗流对复合坚硬岩石材料支护的巷道环境断裂失稳的影响 ,提出相应工程治理措施 ,这对以坚硬岩石复合材料支护为骨架的锚注支护塌陷区是一个大胆的尝试。     

锦屏一级水电站普斯罗沟左岸深部裂缝成因的工程地质分析

通过对锦屏一级水电站普斯罗沟坝址左岸深部裂缝空间发育规律、深部裂缝变形特征的考察 ,从地质、力学、数值方法多方面分析了造成深部裂缝发育规律和变形特征的因素。在此基础上明确指出 ,普斯罗沟左岸深部裂缝的成因就是边坡在自重应力和构造应力的复合应力场卸荷的结果 ,没有超出常规意义下边坡卸荷作用的范畴。     

地面沉降变形破坏实例分析

某水库在2010年汛期运行中,溢洪道下游出水渠左岸出现大面积地面沉降现象,并伴随有大面积地面裂缝,且局部出现坍塌现象,严重影响周围居民的正常生活和出行安全,一旦垮塌,将对水库行洪产生极大的影响。文章通过调查沉降区工程地质及水文地质条件,详细描述沉降区形态,深入分析了产生破坏变形的原因。结果表明:降雨入渗是导致大面积地面沉降及局部坍塌的主要原因,回填区土体结构杂乱且松散,透水性强,亦具备形成沉降的岩性结构条件。     

射孔孔眼磨蚀对分段压裂裂缝扩展的影响

非常规油气藏分段压裂施工中常利用射孔限流法促进段内多条水力裂缝均匀发育,压裂过程中,支撑剂会逐渐磨蚀射孔孔眼,致使射孔孔眼的限流作用失效。为研究射孔孔眼磨蚀现象对分段压裂中多裂缝发育的影响情况,耦合了孔眼磨蚀模型和水力裂缝扩展模型,建立了考虑射孔孔眼磨蚀的水平井分段压裂裂缝扩展模型。模拟结果表明:随着支撑剂磨蚀破坏射孔孔眼,孔眼的限流能力显著下降,导致压裂段内各水力裂缝尺寸差距增大。基于所建立的数值模型,研究了不同支撑剂浓度、压裂液排量条件下射孔孔眼磨蚀对压裂段内多条水力裂缝扩展的影响。结果表明:(1)压裂液内支撑剂浓度越高,射孔孔眼初期的磨蚀速度越快;(2)支撑剂浓度变化对段内裂缝扩展延伸的影响较小;(3)压裂液排量越高,射孔孔眼限流效果越好,压裂段内各裂缝发育越均匀。最后建议在分段压裂施工中尽可能提高压裂液排量,这将有助于压裂段内各裂缝的均衡发育。     

Flexible Osteogenic Glue as an All-In-One Solution to Assist Fracture Fixation and Healing

Osteogenic glue that reproduces the natural bone composition represents the final frontier of orthopedic adhesives with the potential to revolutionize surgical strategies against comminuted fractures. However, it is difficult to achieve an all-in-one formula, which could provide flexible and reliable adhesiveness while avoiding interfering with or even promoting the healing of glued fractures. Herein, an osteogenic glue characterized by inorganic-in-organic integration between amine-modified mesoporous bioactive glass nanoparticles (AMBGN) and bioadhesive gelatin-dextran network (GelDex) is introduced as an all-in-one tool to flexibly adhere and splice bone fragments and subsequently guide fracture healing during degradation. Relying on such integration, a 4-fold improvement in cohesiveness is presented, followed by a nearly 5-fold enhancement in adhesive strength in ex vivo porcine bone samples. The reversible and re-adjustable adhesiveness also enables glue to effectively splice intricate fragments from highly comminuted fractures in the rabbit radius in an in vivo environment. Moreover, well-preserved organic–inorganic integrity during degradation of the glue guides sustained interfacial osteogenesis and achieve satisfying healing outcomes in glued fractures, as observed by the 2-fold improvement in biomechanical and radiological performance compared with commercially available cyanoacrylate adhesives. The current findings propose an all-in-one solution for the fixation of bone fragments during surgery.     

Migpore,a code package for the estimation of migration of radioactive species in a porous medium

In the event of an accidental leakage of high level radioactive waste buried deep in repositories surrounded by rock, the build up of the concentration of the radioactive species within the rock needs to be assessed. Towards this, we follow the model of Chen and Li and provide a numerical code to solve the relevant partial differential equations using a compact finite difference scheme.     

经皮椎体后凸成形术治疗骨质疏松性椎体压缩性骨折临床观察

目的评价经皮椎体后凸成形术（PKP）治疗骨质疏松性椎体压缩性骨折的临床疗效。方法自2009年2月至2010年5月对19例共22个骨质疏松性压缩性椎体采用PKP手术治疗,随访观察患者术前、术后3 d、术后1个月疼痛视觉模拟评分（VAS）、Oswestry功能评分,椎体高度和Cobb角。结果 VAS评分由术前平均（8.54±2.12）分改善到术后3 d（2.42±1.75）分,术后1个月（2.56±1.69）分;Oswestry评分由术前（42.42±9.53）分改善到术后3 d（20.65±4.62）分,术后1个月（21.63±6.83）分;椎体前、中、后高度由术前（1.76±0.57、1.98±0.69、2.57±0.54）cm改善到术后3 d（2.42±0.32、2.53±0.42、2.69±0.35）cm,术后1个月（2.41±0.33、2.53±0.43、2.70±0.31）cm;Cobb角由术前的（28.52±8.45）°改善到术后3 d（20.35±6.76）°,术后1个月（21.42±7.11）°。VAS评分、Oswestry功能评分、椎体高度（前缘、中部及后缘）和Cobb角在术前与术后3 d比较差异有统计学意义（P〈0.05）,术前与术后1个月比较差异有统计学意义（P〈0.05）,术后3 d与术后1个月相比较差异无统计学意义（P〉0.05）。结论经皮椎体后凸成形术治疗骨质疏松性椎体压缩性骨折疗效显著,能在短期内明显缓解疼痛症状,减少腰背部功能障碍提高生活治疗,有效提高椎体高度,适度恢复脊柱生理曲度,是一种安全、有效的治疗方法。     

小儿肱骨髁上骨折的临床诊治

目的了解小儿肱骨髁上骨折的临床表现,探讨闭合复位经皮克氏针对小儿肱骨髁上骨折的临床治疗方法。方法将60例肱骨髁上骨折患者随机分为2组,Ⅰ组30例使用闭合复位经皮克氏针内固定治疗,Ⅱ组30例使用切开复位克氏针固定治疗,然后比较2组疗效。结果Ⅰ组治疗方法的优良率显著高于Ⅱ组,P<0.05。结论闭合复位经皮克氏针内固定治疗小儿肱骨髁上骨折的疗效比切开复位克氏针固定治疗的疗效好。