Pharmacological effects and mechanisms of YiYiFuZi powder in chronic heart disease revealed by metabolomics and network pharmacology

Introduction: YiYiFuZi powder (YYFZ) is a classical formula in Chinese medicine, which is commonly used clinically for the treatment of Chronic Heart Disease (CHD), but it’s pharmacological effects and mechanism of action are currently unclear.Methods: An adriamycin-induced CHD model rat was established to evaluate the pharmacological effects of YYFZ on CHD by the results of inflammatory factor level, histopathology and echocardiography. Metabolomic studies were performed on rat plasma using UPLC-Q-TOF/MS to screen biomarkers and enrich metabolic pathways; network pharmacology analysis was also performed to obtain the potential targets and pathways of YYFZ for the treatment of CHD.Results: The results showed that YYFZ significantly reduced the levels of TNF-α and BNP in the serum of rats, alleviated the disorder of cardiomyocyte arrangement and inflammatory cell infiltration, and improved the cardiac function of rats with CHD. The metabolomic analysis identified a total of 19 metabolites, related to amino acid metabolism, fatty acid metabolism, and other metabolic pathways. Network pharmacology showed that YYFZ acts through PI3K/Akt signaling pathway, MAPK signaling pathway and Ras signaling pathway.Discussion: YYFZ treatment of CHD modulates blood metabolic pattern and several protein phosphorylation cascades but importance specific changes for therapeutic effect require further studies

Submerged boiling and jet impingement for cooling high power electronics

The submerged boiling is expected to be a good solution for the ever-increasing cooling demands of electronic devices in the industries including automotive vehicles, aircraft and spacecraft avionics, power inverters, military equipment, mobile devices, supercomputers, and data centers. Although it has been investigated extensively, the development and application of the submerged boiling systems still face some challenging issues: (i) a comprehensive understanding of the heat transfer mechanism is lacked; (ii) results from similar experimental condition are often divergent or even contradictory; (iii) augmentation methods are usually necessary due to poor thermal properties of dielectric fluids; (iv) a universal prediction tool is absent. This thesis contributes to part of the pressing issues mentioned above to further understand the submerged boiling. To distinguish the large-scale component and the short-scale component in the three-dimensional (3D) surface analysis, arithmetic mean heights for the primary surface and the surface roughness component have been defined as 3D roughness parameters. The effects of the 3D roughness parameters on the pool boiling heat transfer are experimentally investigated on eight testing surfaces fabricated through three different preparation methods. Experimental results show that a rougher surface has higher heat transfer coefficient than a smoother one only within the same surface preparation method, if the surface roughness is characterized by the parameter derived from the primary surface. However, a different trend is observed when the parameter from the roughness component is applied to characterize the surface roughness. The boiling curves are found to shift monotonically to the left as the roughness parameter becomes larger, regardless of the surface preparation methods. A correlation is developed to well predict the heat transfer coefficient as a function of the surface roughness. Titania nanotube arrays are anodized on titanium plate in an electrochemical system and the potential application of this type of nanotube in two-phase submerged cooling system is explored. Experimental results show that the titania nanotubes are effective in improving both the cooling performance and the thermal safety margin of a two-phase submerged cooling system for titanium-based devices. However, its applications in devices based on other materials should be cautious unless the potential effect of the thermal interface resistance between the device surface and the nanotube coating can be eliminated. The nanotube structures are recognized to provide faster liquid replenishment hence modify the bubble dynamics and improve the dry spot rewetting capacity. A submerged jet impingement boiling system with a single circular nozzle is proposed to investigate the steady-state heat transfer characteristics at the stagnation point from single phase convection to partial nucleate boiling. The onset of nucleate boiling is highlighted. The impacts of various parameters including jet Reynolds number, liquid subcooling, and nozzle diameter on the heat transfer characteristics of the onset of nucleate boiling are discussed. Empirical correlations are proposed based on the experimental data to predict the local heat transfer coefficient, heat flux, and wall superheat at the onset of nucleate boiling. The future research directions are suggested for the submerged boiling heat transfer. Firstly, the departure characteristics of the single bubble are suggested to be investigated under different experimental conditions to explore its dependence on the control parameters hence help further understand the departure mechanism of nucleation bubbles. The second suggestion is to design the elaborate surface structures to separate the liquid and vapor flow pathways. In particular, the 3D printing method can provide more flexibility in designing the surface structures and it will be very interesting to apply the 3D printing in designing separated liquid-vapor flow pathways. Lastly, models for the nucleation site density, bubble departure diameter, and bubble departure frequency will be developed based on the quantitative analysis of the bubble dynamics study in this thesis. The developed models are expected to improve the accuracy of bubble dynamics models hence enhance the reliability of the Rensselaer-Polytechnic Institute (RPI) boiling model in numerical simulations.Doctor of Philosoph

A review of two-phase submerged boiling in thermal management of electronic cooling

The increasing cooling demands of electronics have attracted more attention recently for heat removal at the component with higher heat flux and heat density. Boiling, as a two-phase cooling method, is able to achieve a rapid heat removal capacity by utilizing the latent heat from liquid to vapor phase change. It is being expected to be a good solution for cooling electronics with high heat dissipation rate. The present review examines heat transfer performance of the submerged boiling configurations, namely pool boiling, submerged jet impingement and confined jet impingement. The heat transfer characteristics examined are onset of nucleate boiling, nucleate boiling heat transfer coefficient and critical heat flux (CHF). The investigations on working fluids (traditional coolant, dielectric fluids and nanofluids) are summarized and compared. The effects of surface parameters (surface roughness, contact angle, heater size, surface orientation, surface aging and surface structures) on boiling heat transfer are discussed. Contradictory results regarding the effects of jet parameters in submerged/confined jet impingement boiling are reported, suggesting that the heat transfer mechanism of submerged/confined jet impingement boiling should be further investigated. On the other hand, it is confirmed that the submerged jet is effective in delaying CHF by providing sufficient liquid replenishing to the heated surface. A novel kind of surface structure which introduces separate liquid-vapor flow pathways in pool boiling, is discussed in detail. These surfaces introduce submerged jets in pool boiling by the elaborate surface structures but not the traditional jet generation systems. It can provide us the possibility of designing a system with heat removal capacity in submerged jet impingement level, keeping the system away from pumping power and moving parts.Nanyang Technological UniversityThe authors would like to thank the support from DSTA-NTU research agreement and IGS scholarship support

Pool boiling heat transfer of saturated water on rough surfaces with the effect of roughening techniques

The effect of surface roughness on pool boiling heat transfer was experimentally investigated in the saturated water. Eight testing surfaces were fabricated on plain copper through three preparation methods including random polishing, unidirectional polishing, and femtosecond laser machining. The surface roughness in the present study is characterized by the areal (three dimensional, 3D) roughness parameter. In the two dimensional (2D) profile roughness analysis, we know that a profile can be separated into the large-scale component (waviness) and the short-scale component (roughness). The arithmetical mean height of the profile, the waviness and the roughness are denoted as Pa, Wa, and Ra, respectively. However, there are no such kind of parameters defined in the 3D roughness analysis. To distinguish them, we define Sap and Sa in this study, corresponding to Pa and Ra in the 2D roughness parameters. The pool boiling experiments show that a rougher surface has higher heat transfer coefficient than a smoother one only within the same surface preparation method, if the surface roughness is characterized by Sap. For the surfaces prepared by the different techniques, the laser processed rough surface with Sap=3.40 µm could have deteriorated heat transfer coefficient compared with the relatively smooth one polished by the 180 grit sandpaper with Sap=1.29µm. However, the different trend is observed when the surface roughness is characterized by Sa. By applying a standardized filtration process, the large-scale component of the surface can be removed, and the areal arithmetical mean height calculated from the remaining part is denoted as Sa. The boiling curves are found to shift monotonically to the left as Sa becomes larger, regardless of the surface preparation methods. The enhancement in heat transfer coefficient of rougher surfaces is attributed to a combined result of larger nucleation sites, smaller departure bubbles and higher bubble departure frequencies, according to the visualization study. On the other hand, the critical heat flux (CHF) does not show a clear trend with the surface roughness when the different surface preparation methods are involved, no matter Sap or Sa is used. The measurements of static contact angle infer that the CHF is not only dependent on surface roughness, but also highly related to surface wettability. A correlation is developed to well predict the heat transfer coefficient from the experiments as a function of Sa, especially in the fully developed nucleate boiling region.Nanyang Technological UniversityThe authors would like to thank the support from DSTA-NTU research agreement and the IGS scholarship support

Nucleate pool boiling heat transfer on a titania nanotube-coated surface

Enhancing nucleate boiling using surface modification techniques has become to a major topic of interest in pool boiling studies. In this paper, experiments are conducted on a vertically oriented copper surface and a titanium surface coated with TiO2 nanotubes. The nanotube coating is fabricated by a specific anodization process using ethylene glycol as the anodizing solution. A highly wetting dielectric coolant, Novec 7100, is used as the working fluid. A copper block heated by ceramic heater is used to simulate the high power density electronic. The nanotube coated surface shows a significant CHF (critical heat flux) enhancement up to 54% when compared to the plain copper. Various empirical correlations are applied to predict the experimental data. Among all the empirical correlations, the Rosehnow correlation and the Kutateladge correlation give good agreement with the measured data from the plain copper surface.Nanyang Technological UniversityPublished versionThis work is supported by the Nanyang Technological University Research Scholarship

System-level experimental investigations of the direct immersion cooling data center units with thermodynamic and thermoeconomic assessments

The study is to perform thermodynamic, economic and thermoeconomic assessments for two different direct immersion cooling data center systems which are the single-phase and the two-phase immersion cooling systems with the operating ranges of 3.2–27.6 kW and 6.8–15.9 kW, respectively. The two-phase cooling system achieves 72–79% better coefficient of performance trends than the single-phase cooling system. According to the present worth method, the replacement and the energy costs are found as the most dominant future cost terms for the two-phase and the single-phase cooling systems, respectively. The annual exergy cost of the two-phase cooling system is found up to 4.91 times the annual energy costs due to the dominant effects of the destruction and loss terms. Moreover, both cooling data center systems are compared to the existing air-cooled data center unit. They are found economically infeasible for the server power rates below 5 kW because of their higher capital investment costs while they become more affordable for higher server power rates with lower future cost terms.Defence Science and Technology Agency (DSTA)Economic Development Board (EDB)Nanyang Technological UniversityThe authors would like to thank the funding supports from the joint project of Nanyang Technological University (NTU) and Defense Science and Technology Agency, and the Economics Development Board Singapore - EcoCampus at NTU project

Two-phase liquid-immersion data center cooling system : experimental performance and thermoeconomic analysis

The liquid-cooling data center (DC) systems have been becoming important for the rapidly developing high-performance processors since the traditional air-cooled DC systems cannot efficiently manage them due to high heat dissipation rates. Two-phase liquid-immersion cooling is one of the promising direct liquid-cooled DC systems, but its system-scale thermal management performance has not been investigated in detail yet. This study performs the system-scale thermal management of a two-phase liquid-immersion cooling DC system under six different real-time and dynamic operation loads in the range of 3.43-9.17 kW to see the thermodynamic and thermoeconomic performances. The system includes the DC server tank, circulation pump, and dry tower. Results show that the best coefficient of performance (COP) and power usage effectiveness (PUE) values are seen at the highest operation load with 6.67 and 1.15 while the minimum COP and the highest PUE are seen at the lowest operation load with 2.5 and 1.4, respectively. In the component-based assessments, the dry tower is found as the most dominant component according to the exergy destruction ratio analysis, energy costing, and carbon-related costs. The exergy efficiency varies between 8.0% and 18.9% for different operation loads, and the operating temperatures have a crucial impact on the exergetic performances. The thermoeconomic analysis deduces that the levelized product cost is roundly 1.14 S$ · h-1 which means the exergy-related terms (e.g. destruction and loss) increase the costing trends 3.25 times as high compared to the traditional energy-based economic calculations.Agency for Science, Technology and Research (A*STAR)The authors would like to thank the funding supports from the Nanyang Technological University (NTU)-Defense Science and Technology Agency (DSTA) joint project and the Economics Development Board (EDB) Singapore - EcoCampus at NTU project

Ginseng Compatibility Environment Attenuates Toxicity and Keeps Efficacy in Cor Pulmonale Treated by Fuzi Beimu Incompatibility Through the Coordinated Crosstalk of PKA and Epac Signaling Pathways

Cor pulmonale is characterized by severe right ventricular dysfunction caused by lung disease, particularly chronic obstructive pulmonary disease, which can lead to pulmonary hypertension. Our previous study has demonstrated that Fuzi and Beimu compatibility (FBC), a traditional TCM compatibility taboo, improves lung function in early-stage of pulmonary hypertension through the synergistic action of β-ARs signals. However, FBC increases cardiotoxicity with prolonged treatment and disease progression. Considering that the compatibility environment influences the exertion of the medicine, we selected ginseng for coordinating the compatibility environment to improve the security and extend the therapeutic time window of FBC. Monocrotaline-induced cor pulmonale rats were treated with FBC, ginseng, or ginseng combined with FBC (G/FBC). Then, the pulmonary and cardiac functions of the rats were examined to evaluate the toxicity and efficacy of the treatments. The crosstalk between PKA and Epac pathways was also studied. Results showed that G/FBC ameliorated lung function similar to or even better than FBC treatment did. Furthermore, G/FBC treatment attenuated FBC-induced cardiotoxicity, which significantly restored cardiac dysfunction and clearly decreased myocardial enzymes and apoptosis. The βAR-Gs-PKA/CaMKII pathway was inhibited and the Epac1/ERK1/2 axis was activated in G/FBC group. These findings indicate that ginseng compatibility environment could improve pulmonary function and attenuate cardiotoxicity in cor pulmonale via the coordinated crosstalk of PKA and Epac pathways, implying that ginseng could be used to prevent detrimental cardiotoxicity in cor pulmonale treatment