Water-inrush mechanism from the head-on working face roof in a Jurassic coal seam in the Ordos Basin.

When Chinese coal mines are mining Carboniferous Permian coal seams, the mechanism of water inrush from the roof of the working face usually conforms to the "Upper Three Zones" or "Upper Four Zones" theory. The water inrush passageway is water-conducting fracture zone, and the water inrush position is located in the goaf. However, when mining Jurassic coal seams in Chinese coal mines, the location of water inrush often appears at the head-on working face, above the coal mining machine.

Preventing water-inrush from floor in coal working face with paste-like backfill technology.

In the view of the situation where great economic loss often occurs during mining deep coal seams in Feicheng coal field due to water inrush from the floor Ordovician limestone aquifer, the floor "lower four-zone" theory was used as a guide. 81006 working face of Caozhuang Coalmine in Feicheng coal field was taken as the research background, and paste filling technology was proposed to inhibit or reduce the damaged floor depth caused by mine ground pressure in order to prevent water inrush from the floor Ordovician limestone aquifer. Glue material, coal gangue powder, and fly ash were selected as filling material, and a ground filling system, including a material production system, storage material system, power supply and water supply system, automatic control and measurement system, monitoring and control communications system, emergency response system, and underground filling system, including pipe conveyor system and working face blocking grout loss system, were established to achieve effective filling goaf.

Finite Element Analysis and Comparative Study of 4 Kinds of Internal Fixation Systems for Anterior Cervical Discectomy and Fusion in Children.

Background: Spinal injury in children usually occurs in the cervical spine region. Anterior fixation of the lower cervical spine has been applied in treating pediatric cervical spine injury and disease due to its stable and firm mechanical properties. This study performed finite element analysis and comparison of four different anterior cervical internal fixation systems for children to explore more standard methods of anterior cervical internal fixation in children and seek more effective and safe treatment for children's cervical spine diseases.

Anatomical Study on the Safety of Anterior Cervical Craniovertebral Fusion with Clival Screw Placement in Children Aged 1-6 Years.

Objective: This study aimed to investigate the safety of clival screw placement in children aged 1-6 years.

Methods: The cranial computed tomography data of 92 children aged 1-6 years were divided into three groups, according to age, for three-dimensional reconstruction. Three clival screw placement points were defined: (1) median point A at the middle and upper third of the tripartite distance from the spheno-occipital synchondrosis to the base of the skull; (2, 3) critical points B and C on the horizontal line with point A, where the screw placement passage was parallel to the sagittal plane.

Gray Evaluation of Water Inrush Risk in Deep Mining Floor.

With the increase of the mining intensity of coal resources in China, the geological conditions of minefields have become more and more complex. The mining conditions of high pressure and high stress bring great challenges to the safe mining of coal resources. To accurately evaluate the risk of water inrush from the broken floor under high pressure and high stress, a gray evaluation model coupling the work breakdown structure (WBS), the risk-based supervision (RBS) theory, ordered binary comparison quantization method, and the center-point triangular whitenization weight function was proposed in this paper.

Evaluation of Groundwater Resources and Exploitation Potential: A Case from Weifang City of Shandong Province in China.

With the rapid growth of population and economy, the demand for groundwater resources is also increasing, leading to the exploitation of groundwater in some areas far greater than the recharge, which easily causes a series of environmental geological problems such as groundwater drawdown, water quality deterioration, surface subsidence, and so on. Taking Shouguang water resource in Weifang City, Shandong Province, China, as an example, the water-bearing formation in the study area can be divided into three types: pore water-bearing formation of unconsolidated sediments, karst fissure water-bearing formation of carbonate rock, and bedrock fissure water-bearing formation. According to the pumping test results, the groundwater-richness zones in the study area were delineated first.

Integrin CD11b mediates locus coeruleus noradrenergic neurodegeneration in a mouse Parkinson's disease model.

Background: The loss of locus coeruleus noradrenergic (LC/NE) neurons in the brainstem is reported in multiple neurodegenerative disorders, including Parkinson's disease (PD). However, the mechanisms remain unclear. Strong evidence suggested that microglia-mediated neuroinflammation contributes to neurodegeneration in PD.