Search

To study the effect of three-dimensional reinforcement arrangement on the behavior of a gravelly sand, triaxial tests were performed on specimens reinforced with geogrid sheet, geogrid cell, and one and two layers of geogrid sheet and geocell combination. Specimens with a diameter of 100 mm and a height of 200 mm are sheared under drained condition to monitor the variation of axial and volumetric strains with axial loading under different confining pressures. The results showed that the reinforcement schemes have different effects on soil strength improvement. The inclusion of double layers of geogrid sheet and geocell reinforcement could increase both the apparent cohesion and friction of the reinforced soil. The stress-strain relationship could be modelled with a modified hyperbolic model, which can capture the softening strain behavior of the specimens after peak strength.

In view of the dynamic response of geogrid-reinforced gravel under high-speed train load, this paper explores the dynamic characteristics of geogrid-reinforced gravel under semi-sine wave cyclic loading. A number of large scale cyclic triaxial tests were performed on saturated gravelly soil reinforced with geogrid to study the influence of the number of reinforcement layers and loading frequencies on the dynamic responses of reinforced gravelly sand subgrade for high speed rail track. The variation of cumulative axial and volumetric strains, excess pore pressure and resilient modulus with number of loading cycles, loading frequency, and reinforcement arrangement are analyzed. The test results reveal that the cumulative axial strain decreases as the number of reinforcement layers increases, but increases with loading frequency. The resilience modulus increases with the number of reinforcement layers, but decreases as the loading frequency increases. The addition of geogrid can reduce the excess pore water pressure of the sample, but it can slightly enhance the rubber mold embedding effect of the sand sample. As the loading frequency increases, the rubber mold embedding effect gradually weakens.

Plants can defend themselves to pathogen and herbivore attack by responding to chemical signals that are emitted by attacked plants. It is well established that such signals can be transferred through the air. In theory, plants can also communicate with each other through underground common mycorrhizal networks (CMNs) that interconnect roots of multiple plants. However, until now research focused on plant-to-plant carbon nutrient movement and there is no evidence that defense signals can be exchanged through such mycorrhizal hyphal networks. Here, we show that CMNs mediate plantplant communication between healthy plants and pathogen-infected tomato plants (Lycopersicon esculentum Mill.). After establishment of CMNs with the arbuscular mycorrhizal fungus Glomus mosseae between tomato plants, inoculation of 'donor' plants with the pathogen Alternaria solani led to increases in disease resistance and activities of the putative defensive enzymes, peroxidase, polyphenol oxidase, chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase and lipoxygenase in healthy neighbouring 'receiver' plants. The uninfected 'receiver' plants also activated six defence-related genes when CMNs connected 'donor' plants challenged with A. solani. This finding indicates that CMNs may function as a plant-plant underground communication conduit whereby disease resistance and induced defence signals can be transferred between the healthy and pathogen-infected neighbouring plants, suggesting that plants can 'eavesdrop' on defence signals from the pathogen-challenged neighbours through CMNs to activate defences before being attacked themselves. [ABSTRACT FROM AUTHOR]

In adults, angiogenic abnormalities are involved in not only tumor growth but several human inherited diseases as well. It is unclear, however, concerning how the normal vascular structure is maintained and how angiogenesis is initiated in normal adults. Using the Cre-LoxP-mediated conditional gene deletion, we show in the present study that in adult mice disruption of the transcription factor recombination signal-binding protein Jκ (RBP-J) in endothelial cells strikingly induced spontaneous angiogenesis in multiple tissues, including retina and cornea, as well as in internal organs, such as liver and lung. In a choroidal neovascularization model, which mimics the angiogenic process in tumor growth and age-related macular degeneration, RBP-J deficiency induced a more intensive angiogenic response to injury. This could be transmitted by bone marrow, indicating that RBP-J could modulate bone marrow-derived endothelial progenitor cells in adult angiogenesis. In addition, in the absence of RBP-J, proliferation of endothelial cells increased significantly, leading to accumulative vessel outgrowth. These findings suggest that in adults RBP-J-mediated Notch signaling may play an essential role in the maintenance of vascular homeostasis by repressing endothelial cell proliferation. [ABSTRACT FROM AUTHOR]

Objective: To explore the interventional therapy and clinical efficacy of extracranial ICA aneurysm., Methods: The clinical data of eight patients with extracranial ICA aneurysm treated by interventional stent implantation from December 2014 to February 2018 in the Neurosurgery Department of the Third Hospital of Mianyang were analyzed. And this research was a retrospective analysis. All patients underwent digital subtraction angiography (DSA) and were diagnosed with extracranial carotid artery aneurysm. These patients, therefore, were treated with interventional stent implantation., Results: Interventional treatment was successfully conducted on all eight patients. In eight patients, the aneurysm cavity was not developed immediately after angiography, and in one case, the aneurysm cavity was developed with coil-assisted embolization. All the internal carotid arteries were well developed, with no complications such as intraoperative rupture, bleeding and thrombosis occur. Follow-up for three months to two years showed that the patients recovered well, the GOS score was 4 points for patients with cerebral infarction, and the rest reached five points. Follow-up CTA showed no signs of aneurysm recurrence or ICA restenosis., Conclusion: Interventional stent placement is a preferable and relatively safe method for the treatment of extracranial carotid artery aneurysm with less trauma and short operation time., Competing Interests: Conflicts of interest: None, (Copyright: © Pakistan Journal of Medical Sciences.)