Suppression of experimental abdominal aortic aneurysms in the rat by treatment with angiotensin-converting enzyme inhibitors

AbstractPurpose: Pathologic remodeling of the extracellular matrix is a critical mechanism in the development and progression of abdominal aortic aneurysms (AAAs). Although angiotensin-converting enzyme (ACE) inhibitors are known to alter vascular wall remodeling in other conditions, their effects on AAAs are unknown. In this study we assessed the effect of ACE inhibitors in a rodent model of aneurysm development. Methods: Male Wistar rats underwent transient aortic perfusion with porcine pancreatic elastase, followed by treatment with one of three ACE inhibitors (captopril [CP], lisinopril [LP], or enalapril [EP]), an angiotensin (AT)1 receptor antagonist (losartan [LOS]), or water alone (9 rats in each group). Blood pressure and aortic diameter (AD) were measured before elastase perfusion and on day 14, with an AAA defined as an increase in AD (ΔAD) of more than 100%. The structural features of the aortic wall were examined by means of light microscopy. Results: Aneurysmal dilatation consistently developed within 14 days of elastase perfusion in untreated rats, coinciding with the development of a transmural inflammatory response and destruction of the elastic media (mean ΔAD, 223% ± 28%). All three ACE inhibitors prevented AAA development (mean ΔAD: CP, 67% ± 4%; LP, 18% ± 12%; and EP, 14% ± 3%; each P <.05 vs controls). ACE inhibitors also attenuated the degradation of medial elastin without diminishing the inflammatory response. Surprisingly, the aneurysm-suppressing effects of ACE inhibitors were dissociated from their effects on systemic hemodynamics, and LOS had no significant effect on aneurysm development compared with untreated controls (mean ΔAD, 186% ± 19%). Conclusion: Treatment with ACE inhibitors suppresses the development of elastase-induced AAAs in the rat. Although this is associated with the preservation of medial elastin, the mechanisms underlying these effects appear to be distinct from hemodynamic alterations alone or events mediated solely by AT1 receptors. Further studies are needed to elucidate how ACE inhibitors influence aortic wall matrix remodeling during aneurysmal degeneration. (J Vasc Surg 2001;33:1057-64.

Suppression of experimental abdominal aortic aneurysms in the rat by treatment with angiotensin-converting enzyme inhibitors

AbstractPurpose: Pathologic remodeling of the extracellular matrix is a critical mechanism in the development and progression of abdominal aortic aneurysms (AAAs). Although angiotensin-converting enzyme (ACE) inhibitors are known to alter vascular wall remodeling in other conditions, their effects on AAAs are unknown. In this study we assessed the effect of ACE inhibitors in a rodent model of aneurysm development. Methods: Male Wistar rats underwent transient aortic perfusion with porcine pancreatic elastase, followed by treatment with one of three ACE inhibitors (captopril [CP], lisinopril [LP], or enalapril [EP]), an angiotensin (AT)1 receptor antagonist (losartan [LOS]), or water alone (9 rats in each group). Blood pressure and aortic diameter (AD) were measured before elastase perfusion and on day 14, with an AAA defined as an increase in AD (ΔAD) of more than 100%. The structural features of the aortic wall were examined by means of light microscopy. Results: Aneurysmal dilatation consistently developed within 14 days of elastase perfusion in untreated rats, coinciding with the development of a transmural inflammatory response and destruction of the elastic media (mean ΔAD, 223% ± 28%). All three ACE inhibitors prevented AAA development (mean ΔAD: CP, 67% ± 4%; LP, 18% ± 12%; and EP, 14% ± 3%; each P <.05 vs controls). ACE inhibitors also attenuated the degradation of medial elastin without diminishing the inflammatory response. Surprisingly, the aneurysm-suppressing effects of ACE inhibitors were dissociated from their effects on systemic hemodynamics, and LOS had no significant effect on aneurysm development compared with untreated controls (mean ΔAD, 186% ± 19%). Conclusion: Treatment with ACE inhibitors suppresses the development of elastase-induced AAAs in the rat. Although this is associated with the preservation of medial elastin, the mechanisms underlying these effects appear to be distinct from hemodynamic alterations alone or events mediated solely by AT1 receptors. Further studies are needed to elucidate how ACE inhibitors influence aortic wall matrix remodeling during aneurysmal degeneration. (J Vasc Surg 2001;33:1057-64.

Development of artificial shape-setting energy storage phosphorous building gypsum aggregate

The research and development of new building materials such as phosphorous building gypsum is crucial to promote the utilisation of phosphogypsum resources by improving their value. This study developed a new type of shape-stabilised energy storage phosphorus building gypsum aggregate (ES-PBGA). The mechanical and thermal properties of ES-PBGA with Paraffin were investigated. The results indicate that the matrix of ES-PBGA had a good microstructure, and the optimal paraffin-embedding rate of ES-PBGA was 31.08%. The phase transition temperature and enthalpy of the endothermic and exothermic stages were 17.6 and 27.14 ℃, and 33.02 and 31.62 J/g, respectively. The cylinder pressure strength of ES-PBGA with paraffin (31.08%) was 4.32 MPa, which meets the requirements of artificial aggregate application. To verify the practicability of ES-PBGA, energy storage lightweight aggregate concrete was prepared with 0%, 25%, 50%, and 100% ES-PBGA to replace the lightweight shale ceramsite. The results show that ES-PBGA can improve the interface transition zone between cement-based materials and energy storage aggregates, thereby improving the strength, and has a relatively suitable thermal conductivity, thermal diffusion coefficient, and specific heat capacity. Furthermore, it is also a type of low-carbon energy storage aggregate, and its application in the field of energy storage composite building materials is a relatively new concept

Preparation and Pore Structure of Energy-Storage Phosphorus Building Gypsum

In this study, the pore structure of a hardened phosphorous building gypsum body was optimised by blending an air-entraining agent with the appropriate water–paste ratio. The response surface test was designed according to the test results of the hardened phosphorous building gypsum body treated with an air-entraining agent and an appropriate water–paste ratio. Moreover, the optimal process parameters were selected to prepare a porous phosphorous building gypsum skeleton, which was used as a paraffin carrier to prepare energy-storage phosphorous building gypsum. The results indicate that if the ratio of the air-entraining agent to the water–paste ratio is reasonable, the hardened body of phosphorous building gypsum can form a better pore structure. With the influx of paraffin, its accumulated pore volume and specific surface area decrease, and the pore size distribution is uniform. The paraffin completely occupies the pores, causing the compressive strength of energy-storage phosphorous building gypsum to be better than that of similar gypsum energy-storing materials. The heat energy further captured by energy-storage phosphorous building gypsum in the endothermic and exothermic stages is 28.19 J/g and 28.64 J/g, respectively, which can be used to prepare energy-saving building materials

Effects of particle shaping on the performance of phosphorus building gypsum

Phosphogypsum (PG) is an industrial by-product from the wet preparation of phosphoric acid. Phosphorus building gypsum (PBG) can be obtained from PG after high-thermal dehydration. Improving the properties of PBG is of great significance to extending its application range. In this paper, PBG was modified by particle shaping, resultantly its properties have been significantly improved. This study utilized a small-scale ball mill as a power source for simulated shaping to investigate the shape parameters of PBG particles before and after shaping. Further, the effects of different material-to-ball mass ratios, ball milling speeds, and shaping durations on PBG performance were examined. Shaped PBG particles exhibited a reduction in aspect ratio, approaching a roundness of approximately 1. The sharp edges on the particle surfaces decreased, resulting in a particle appearance that tended to approach a spherical form. Moreover, when the material-to-ball mass ratio and ball milling speed were held constant, increasing the shaping duration decreased and then increased the water amount required for normal consistency and setting time of PBG. However, the strength, first increased and then decreased. Under the conditions of a material-to-ball mass ratio of 1:1, ball milling speed of 90 r/min, and a shaping duration of 5 min, PBG exhibited the most significant enhancement in mechanical properties. Finally, the mechanism of how particle shaping affects PBG performance was analyzed using the theory of water film thickness

How to Construct a Power Knowledge Graph with Dispatching Data?

Knowledge graph is a kind of semantic network for information retrieval. How to construct a knowledge graph that can serve the power system based on the behavior data of dispatchers is a hot research topic in the area of electric power artificial intelligence. In this paper, we propose a method to construct the dispatch knowledge graph for the power grid. By leveraging on dispatch data from the power domain, this method first extracts entities and then identifies dispatching behavior relationship patterns. More specifically, the method includes three steps. First, we construct a corpus of power dispatching behaviors by semi-automated labeling. And then, we propose a model, called the BiLSTM-CRF model, to extract entities and identify the dispatching behavior relationship patterns. Finally, we construct a knowledge graph of power dispatching data. The knowledge graph provides an underlying knowledge model for automated power dispatching and related services and helps dispatchers perform better power dispatch knowledge retrieval and other operations during the dispatch process

Projection of Precipitation Extremes and Flood Risk in the China–Pakistan Economic Corridor

It is reported that the China–Pakistan Economic Corridor has been affected by extreme precipitation events. Since the 20th century, extreme weather events have occurred frequently, and the damage and loss caused by them have increased. In particular, the flood disaster caused by excessive extreme precipitation seriously hindered the development of the human society. Based on CRiteria Importance Through Intercriteria Correlation and square root of generalized cross-validation, this study used intensity–area–duration to analyze the trend of future extreme precipitation events, corrected the equidistance cumulative distribution function method deviation of different future scenario models (CESM2, CNRM-CM6-1, IPSL-CM6A-LR, and MIROC6) and evaluated the simulation ability of the revised model. The results showed that: 1) the deviation correction results of CNRM-CM6-1 in the Coupled Model Intercomparison Project Phase (CMIP) 6 could better simulate the precipitation data in the study area, and its single result could achieve the fitting effect of the CMIP5 multimodel ensemble average; 2) under CNRM-CM6-1, the frequency of extreme precipitation events under the three climate scenarios (SSP1-2.6, SSP3-7.0, and SSP5-8.5) presents interdecadal fluctuations of 3.215 times/10A, 1.215 times/10A, and 5.063 times/10A, respectively. The average impact area of extreme precipitation events would decrease in the next 30 years, while the total impact area and the extreme precipitation events in a small range would increase. Under the future scenario, the increase rate of extreme precipitation was highest in August, which increased the probability of extreme events; 3) in the next 30 years, the flood risk had an obvious expansion trend, which was mainly reflected in the expansion of the area of high-, medium-, and low-risk areas. The risk zoning results obtained by the two different flood risk assessment methods were different, but the overall risk trend was the same. This study provided more advanced research for regional flood risk, reasonable prediction for flood risk under future climate models, and useful information for flood disaster prediction in the study area and contributes to the formulation of local disaster prevention and reduction policies

Sox9 potentiates BMP2-induced chondrogenic differentiation and inhibits BMP2-induced osteogenic differentiation.

Bone morphogenetic protein 2 (BMP2) is one of the key chondrogenic growth factors involved in the cartilage regeneration. However, it also exhibits osteogenic abilities and triggers endochondral ossification. Effective chondrogenesis and inhibition of BMP2-induced osteogenesis and endochondral ossification can be achieved by directing the mesenchymal stem cells (MSCs) towards chondrocyte lineage with chodrogenic factors, such as Sox9. Here we investigated the effects of Sox9 on BMP2-induced chondrogenic and osteogenic differentiation of MSCs. We found exogenous overexpression of Sox9 enhanced the BMP2-induced chondrogenic differentiation of MSCs in vitro. Also, it inhibited early and late osteogenic differentiation of MSCs in vitro. Subcutaneous stem cell implantation demonstrated Sox9 potentiated BMP2-induced cartilage formation and inhibited endochondral ossification. Mouse limb cultures indicated that BMP2 and Sox9 acted synergistically to stimulate chondrocytes proliferation, and Sox9 inhibited BMP2-induced chondrocytes hypertrophy and ossification. This study strongly suggests that Sox9 potentiates BMP2-induced MSCs chondrogenic differentiation and cartilage formation, and inhibits BMP2-induced MSCs osteogenic differentiation and endochondral ossification. Thus, exogenous overexpression of Sox9 in BMP2-induced mesenchymal stem cells differentiation may be a new strategy for cartilage tissue engineering