Height of fractured zone inside overlying strata under high-intensity mining in China

The height of fractured zone(HFZ) at the high-intensity longwall mining panel plays a vital role in the safety analysis of coal mining under bodies of water. This paper described definitions of the highintensity mining. The processes of overburden failure transfer(OFT) were analyzed, which were divided into the development stage and the termination stage. Through theoretical analysis, the limited suspension-distance and the limited overhanging distance were proposed to judge the damage of each stratum. Mechanical models of strata suspended integrity and overhanging stability were established.A theoretical method to predict the HFZ at the high-intensity longwall mining panel was put forward based on the processes of OFT. Taking a high-intensity longwall mining panel(No. 11915 panel) as an example, the theoretical method proposed, the engineering analogy and the empirical formulas in the Regulation were used to predict the HFZ. The results show that the theoretical result is consistent with the engineering analogies' result and empirical formulas' result. The rationality and reliability of the theoretical method proposed is verified.

Shape Effect of Piezoelectric Energy Harvester on Vibration Power Generation

Vibration energy harvesting is widely recognized as the useful technology for saving energy. The piezoelectric energy harvesting device is one of energy harvester and is used to operate certain types of MEMS devices. Various factors influence the energy regeneration efficiency of the lead zirconate titanate piezoelectric (PZT) devices in converting the mechanical vibration energy to the electrical energy. This paper presents the analytical and experimental evaluation of energy regeneration efficiency of PZT devices through impedance matching method and drop-weight experiments to different shape of PZT devices. The results show that the impedance matching method has increased the energy regeneration efficiency while triangular shape of PZT device produce a stable efficiency in the energy regeneration. Besides that, it becomes clear that the power, energy and subsequently efficiency of the triangular plate are higher than those of the rectangular plate under the condition of the matching impedance and the same PZT area.

肿瘤双自杀基因治疗系统pTRKH2-PsT/CD,pTRKH2-PsT/UPRT在厌氧婴儿双歧杆菌中的构建(英文)

Objective:We recombine the suicide gene CD,UPRT into plasmid pTRKH2 and clone the recombinant dual suicide gene therapy system into tumor-hypoxia-targeting vector Bifidobacterium infantis and characterize its function.Methods:CD gene,UPRT gene and lactic acid bacteria expression plasmid pTRKH2 were digested by restriction endonuclease BamH I and Sal I,and constructed recombinant plasmids pTRKH2/CD and pTRKH2/UPRT in E.coli.The recombinant plasmids were then transfected into Bifidobacterium Infantis by electroporation.Identification of pTRKH2/CD and pTRKH2/UPRT was processed by dual restriction endonuclease digesting and sequencing.RT-PCR and SDS-PAGE were used to examine the expression of CD and UPRT genes at RNA and protein levels.The killing effects on Melanoma B16-F10 cells by pTRKH2/CD and pTRKH2/UPRT suicide gene therapy system with 5-FC were examined by MTT assay.Results:The CD gene and UPRT gene was successfully recombined into lactic acid bacteria expression plasmid pTRKH2.After dual endonuclease digestion of plasmid purified from the positively transfected E.coli,two fragments of 6.9 Kb and 1.3 Kb were found for CD gene and two fragments of 6.9 Kb and 620 bp were found for UPRT gene.The sequencing of CD gene and UPRT gene proved consistent sequences with Genebank published data.A fragment of 1.3 Kb for CD gene and fragment of 620 bp for UPRT gene was found in recombinant Bifidobacterium by RT-PCR.A 52 KDa protein for CD gene was identified in whole-cell protein of recombinant Bifidobacterium and a 26 KDa protein for UPRT gene was identified in supernatant fluid of recombinant Bifidobacterium.The survival rate of tumor cells treated by extracts from culture of recombinant Bifidobacterium with 5-FC showed a strong killing effects of pTRKH2/CD and pTRKH2/UPRT dual suicide gene therapy system on Melanoma B16-F10 cells.Conclusion:CD gene and UPRT gene are successfully inserted into pTRKH2 and transfected into tumor-hypoxia-targeting vector Bifidobacterium Infantis.This dual suicide gene therapy system shows a high efficiency for tumor cells killing.

Study on the Deformation Mechanism of a Soft Rock Tunnel

The large deformation of soft rock tunnel is one of the key problems to be overcome in the tunnel construction stage.In the present study,the deformation mechanism of a representative tunnel and some related countermeasures are investigated using field tests and engineering geological analysis.Owing to the scarce performances of methods based on other criteria such as small pipe spacing,anchor bolt length and steel frame spacing,a new support scheme is implemented and optimized.Results show that shear failure and bedding sliding are produced under high horizontal stress conditions.The low strength of the surrounding rock results in the uneven convergence of both sides of the tunnel.With the aforementioned new support scheme,however,most of such problems can be mitigated leading to good stability properties and ensuing economic advantages.

Research progress of microRNA in prevention and treatment of osteonecrosis of the femoral head

20世纪80年代,Feinbaum等人在蠕虫的生长发育过程中首次发现了miRNA,并将其命名为Lin-4。随着微生物学的发展和基因测序技术的不断完善,miRNA逐渐成为临床医学研究的热点。其中一组miRNA已被证实在骨肿瘤、骨关节炎、类风湿关节炎等骨科疾病的基因调控中发挥着基础性作用。研究miRNA在股骨头坏死(ONFH)中的作用可以提高对该病发病机制的认识。ONFH是一种骨科疾病,是导致股骨头血供紊乱的主要原因,主要症状是骨骼、肌肉功能障碍。近期的研究表明,miRNA在调节ONFH微循环、血管损伤修复、其他疾病引起的局部微循环功能障碍、骨细胞凋亡等方面发挥了重要作用。本文分析和总结了近期的miRNA和ONFH相关研究成果,并展望了其在疾病防治方面的前景。

Imaging-Guided Cancer Therapy Based on Multifunctional Magnetic Nanoparticles

In recent years,magnetic nanoparticles(MNPs)have received great attention within the field of biomedicine,especially for cancer therapy.This is because MNPs have many excellent physical and chemical properties to provide sufficient imaging information along with satisfactory therapeutic efficacy.Moreover,by virtue of various modification strategies,the obtained multifunctional MNPs can further achieve synergized multimodal cancer theranostic,which is worthy of further study.In this review,we summarize the recent developments in imaging-guided strategies and synergistic cancer therapy based on multifunctional MNPs.Then,we discuss the challenge and perspective of the next generation of MNPs-based imaging-guided cancer therapy,hoping to provide guidance in potential applications.

Temperature and Tumor Microenvironment Dual Responsive Mesoporous Magnetic Nanospheres for Magnetothermal Effect-Induced Cancer Theranostics

The development of smart drug delivery systems(SDDSs)based on engineered nanomaterials is important for clinical applications.Nevertheless,controllable administration of chemotherapeutic drugs for deep tumors and the avoidance of side effects caused by off-targeting during delivery remain a great challenge.Herein,a stimulus-responsive system of mesoporous nanospheres(composed of Cu@Fe_(2)C@mSiO_(2))with good magnetothermal effect is introduced into the tumor microenvironment.This system plays an important role in image-guided controllable targeted drug delivery that is independent of tumor depth.Aggregation-induced emission luminogen-based fluorescence imaging and magnetic resonance imaging were utilized since these techniques visualize the delivery process in real time.In addition,the degraded nanocarriers showed high catalytic activity for Fenton and Fenton-like reactions,upregulating the level of hydroxyl radicals(•OH)in cancer cells to realize chemodynamic therapy.The induced•OH led to the overexpression of pho-STAT3,activating the STAT3 signaling pathway,eventually inducing cancer cell apoptosis.Through metabolic monitoring,this SDDS is removed from the body after its degradation in vivo.The synergistically enhanced therapeutic effect was obtained in the chemo-chemodynamic therapy of 4T1 tumor-bearing mice,offering a platform for efficient cancer therapy with a personalized theranostic strategy.

Self-assembled magnetic nanomaterials:Versatile theranostics nanoplatforms for cancer

Self-assembled magnetic nanomaterials(MNMs)are a class of promising biomaterials possessing excellent physiochemical and biological characteristics,making them highly attractive in biomedical applications.A myriad of magnetic nanosystems can be created by using self-assembly as a synthetic tool.Favorable nano-bio interfacial properties are shown in these promising self-assembled magnetic nanosystems,while still retaining their physical/chemical functionalities.This review aims to provide a systematical overview of the self-assembled MNMs.In addition,this review highlights their implementations in cancer theranostics in detail.Overall,this review points out the direction for the application of self-assembled MNMs in biomedicine,and presents how clinical oncology could benefit from the self-assembled nanotechnology.