Distributed Acoustic Sensing for Monitoring Linear Infrastructures: Current Status and Trends.

Linear infrastructures, such as railways, tunnels, and pipelines, play essential roles in economic and social development worldwide. However, under the influence of geohazards, earthquakes, and human activities, linear infrastructures face the potential risk of damage and may not function properly. Current monitoring systems for linear infrastructures are mainly based on non-contact detection (InSAR, UAV, GNSS, etc.) and geotechnical instrumentation (extensometers, inclinometers, tiltmeters, piezometers, etc.) techniques. Regarding monitoring sensitivity, frequency, and coverage, most of these methods have some shortcomings, which make it difficult to perform the accurate, real-time, and comprehensive monitoring of linear infrastructures. Distributed acoustic sensing (DAS) is an emerging sensing technology that has rapidly developed in recent years. Due to its unique advantages in long-distance, high-density, and real-time monitoring, DAS arrays have shown broad application prospects in many fields, such as oil and gas exploration, seismic observation, and subsurface imaging. In the field of linear infrastructure monitoring, DAS has gradually attracted the attention of researchers and practitioners. In this paper, recent research and the development activities of applying DAS to monitor different types of linear infrastructures are critically reviewed. The sensing principles are briefly introduced, as well as the main features. This is followed by a summary of recent case studies and some critical problems associated with the implementation of DAS monitoring systems in the field. Finally, the challenges and future trends of this research area are presented.

Estrogen protects against acidosis-mediated articular chondrocyte injury by promoting ASIC1a protein degradation.

Epidemiological data suggest that the incidence of rheumatoid arthritis (RA) increases in postmenopausal women, which may be related to estrogen deficiency. Tissue acidosis is a common symptom of RA. Acid-sensitive ion channel 1a (ASIC1a), a member of the extracellular H+-activated cation channel family, could be activated by changes in extracellular pH and plays a crucial role in the pathogenesis of RA. As the only cellular component in cartilage tissue, chondrocytes play an extremely important role in maintaining cartilage tissue homeostasis. The aim of this study was to investigate whether estrogen could protect acid-stimulated chondrocytes by regulating the expression of ASIC1a and explore the possible mechanism. The results showed that estrogen could protect against acid-induced chondrocyte injury by reducing ASIC1a protein expression. Moreover, lysosome inhibitor chloroquine (CQ) and autophagy inhibitor 3-methyladeniine (3-MA) could reverse the reduction of ASIC1a protein caused by estrogen, indicating that autophagy-lysosome pathway contributes to estrogen-induced degradation of ASIC1a protein. Furthermore, the down-regulation of ASIC1a expression by estrogen was attenuated by MPP, a specific inhibitor of estrogen-related receptor-alpha (Esrra), indicating that Esrra is involved in the process of estrogen regulating the expression of ASIC1a. Additionally, adenosine 5'-monophosphate (AMP)-activated protein kinase/unc-51-like kinase 1 (AMPK-ULK1) signaling pathway was activated by estrogen treatment, which was abrogated by Esrra-silencing, and AMPK-specific inhibitor Compound C pretreatment could reduce estrogen-induced downregulation of ASIC1a protein. Taken together, these results indicate that estrogen could promote autophagy-lysosome pathway-dependent ASIC1a protein degradation and protect against acidosis-induced cytotoxicity, the mechanisms of which might relate to Esrra-AMPK-ULK1 signaling pathway.

[Effect of zishen shengxue recipe on endogenous erythropoietin in patients with renal anemia undergoing long-term hemodialysis].

OBJECTIVE: To investigate the mechanism of Zishen Shengxue Recipe (ZSR) in treating renal anemia by observing its effect on serum level of endogenous erythropoietin in patients undergoing long-term hemodialysis. METHODS: Sixty renal anemia patients undergoing long-term hemodialysis were randomly and equally assigned to two groups. The treated group was treated with subcutaneous injection of erythropoiesis stimulating factor (rHuEpo) combined with oral intake of ZSR, and the control group treated with rHuEpo alone. They were observed for eight weeks, and the blood levels of endogenous human erythropoietin (Epo), hemoglobin (Hgb), hematocrit (Hct), as well as the residual renal function (RRF) in the two groups were compared. RESULTS: Serum Epo level in the control group was unchanged after treatment (P>0.05), while that in the treated group increased significantly, and showed significant difference in comparing with that in the control group (P<0.05). Levels of Hgb and Hct increased and RRF decreased in both groups (P<0.01), but the treated group showed higher increments and lesser decrement than those in the control group (P<0.05). CONCLUSIONS: ZSR can enhance the blood levels of Hgb, Hct and Epo, postpone the descent of RRF, and correct the anemic status in patients. Its mechanism of action is possibly through alleviating the inhibition of uremic toxin on erythropoiesis, in the meanwhile of promoting the secretion of Epo.