Therapeutic Effects of Chinese Medicine Herb Pair, Huzhang and Guizhi, on Monosodium Urate Crystal-Induced Gouty Arthritis in Rats Revealed by Anti-Inflammatory Assessments and NMR-Based Metabonomics

The present study was undertaken to evaluate the therapeutic effects of Huzhang-Guizhi herb pair (HG), firstly included in Hu-Zhang Power documented in Taiping Shenghui Fang, on monosodium urate (MSU) crystals-induced gouty arthritis in rats. We found that pretreatment with HG in rats with gouty arthritis could significantly attenuate the ankle joint swelling, and this beneficial antigout effect might be mediated, at least in part, by inhibiting tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) production in synovial fluid as well as nuclear transcription factor-κB p65 (NF-κB p65) protein expression in synovial tissue. Moreover, metabonomic analysis demonstrated that 5 and 6 potential biomarkers associated with gouty arthritis in plasma and urine, respectively, which were mainly involved in energy metabolism, amino acid metabolism, and gut microbe metabolism, were identified. HG could reverse the pathological process of MSU-induced gouty arthritis through regulating the disturbed metabolic pathways. These results provided important mechanistic insights into the protective effects of HG against MSU-induced gouty arthritis in rats

Study of chattering suppression for the sliding mode controller of an electromagnetic levitation system

Due to the inherent non-linearity and open-loop instability of maglev systems, their high-quality control performance is critical in the development stage. Sliding mode control has great potential in the field of maglev vehicle control because of its superior control performance, robustness and interference resistance. In practical applications of sliding mode control, however, the limitations of the hardware physical properties and time delay of the control units of maglev systems can cause chattering, thereby significantly reducing the stability of maglev vehicles. In order to suppress chattering, a modified sliding mode controller that combines the exponential reaching law and continuous control laws is proposed in this study. A single-point levitation experimental platform and corresponding co-simulation model were built, and a parameter influence analysis of the modified sliding mode controller was conducted. This paper presents an adaptive correction method for the sliding mode control parameters based on the aforementioned chattering study. The actual levitation experiments were used to validate the control performance of the proposed controllers. Overall, the conducted research revealed that the modified controllers could effectively suppress chattering and possess excellent robustness

Study of chattering suppression for the sliding mode controller of an electromagnetic levitation system

Due to the inherent non-linearity and open-loop instability of maglev systems, their high-quality control performance is critical in the development stage. Sliding mode control has great potential in the field of maglev vehicle control because of its superior control performance, robustness and interference resistance. In practical applications of sliding mode control, however, the limitations of the hardware physical properties and time delay of the control units of maglev systems can cause chattering, thereby significantly reducing the stability of maglev vehicles. In order to suppress chattering, a modified sliding mode controller that combines the exponential reaching law and continuous control laws is proposed in this study. A single-point levitation experimental platform and corresponding co-simulation model were built, and a parameter influence analysis of the modified sliding mode controller was conducted. This paper presents an adaptive correction method for the sliding mode control parameters based on the aforementioned chattering study. The actual levitation experiments were used to validate the control performance of the proposed controllers. Overall, the conducted research revealed that the modified controllers could effectively suppress chattering and possess excellent robustness

NMR-Based Metabonomic Study Reveals Intervention Effects of Polydatin on Potassium Oxonate-Induced Hyperuricemia in Rats

Previous studies have disclosed the antihyperuricemic effect of polydatin, a natural precursor of resveratrol; however, the mechanisms of action still remain elusive. The present study was undertaken to evaluate the therapeutic effects and the underlying mechanisms of polydatin on potassium oxonate-induced hyperuricemia in rats through metabonomic technology from a holistic view. Nuclear magnetic resonance (NMR) spectroscopy was applied to capture the metabolic changes in sera and urine collected from rats induced by hyperuricemia and polydatin treatment. With multivariate data analysis, significant metabolic perturbations were observed in hyperuricemic rats compared with the healthy controls. A total of eleven and six metabolites were identified as differential metabolites related to hyperuricemia in serum and urine of rats, respectively. The proposed pathways primarily included branched-chain amino acid (BCAA) metabolism, glycolysis, the tricarboxylic acid cycle, synthesis and degradation of ketone bodies, purine metabolism, and intestinal microflora metabolism. Additionally, some metabolites indicated the risk of renal injury induced by hyperuricemia. Polydatin significantly lowered the levels of serum uric acid, creatinine, and blood urea nitrogen and alleviated the abnormal metabolic status in hyperuricemic rats by partially restoring the balance of the perturbed metabolic pathways. Our findings shed light on the understanding of the pathophysiological process of hyperuricemia and provided a reference for revealing the metabolic mechanism produced by polydatin in the treatment of hyperuricemia

NMR-Based Metabonomic Studies on Stomach Heat and Cold Syndromes and Intervention Effects of the Corresponding Formulas

Zuojin Wan (ZJW) and Lizhong Wan (LZW) have been widely used in the treatment of Stomach heat and cold syndrome (SH and SC), respectively. In this study, a proton nuclear magnetic resonance (1H NMR) based metabonomic approach was developed to profile SH and SC-related metabolic perturbations in rat serum and to investigate the intervention effects of ZJW and LZW on the corresponding SH and SC. Compared to the conventional macroscopic and histopathological examinations, the metabonomic approach could enable discrimination between SH and SC based on serum metabolic profiles. Meanwhile, 17 and 15 potential biomarkers associated with SH and SC, respectively, which were mainly involved in gastric dysfunction and mucosal lesions, gut microbiotal activity, transmethylation, glucose and lipid metabolism, and amino acid metabolism, were identified. Furthermore, taking the potential biomarkers as drug targets, it was revealed that administration of ZJW and LZW could exclusively reverse the pathological process of SH and SC, respectively, through partially regulating the disturbed metabolic pathways. This work showed biological basis related to SH and SC at metabolic level and offered a new paradigm for better understanding and explanation of “Fang Zheng Dui Ying” principle in traditional Chinese medicine from a systemic view

Research on sliding mode controller of the high-speed maglev train under aerodynamic load

The high-speed maglev train will be subjected to extremely obvious aerodynamic load and instantaneous aerodynamic impact during passing another train, which brings significant challenges to the train's suspension stability and safe operation. It's necessary to consider the influence of aerodynamic load and shock waves in the design of suspension control algorithms. Traditional proportion integration differentiation (PID) control cannot follow the change of vehicle parameters or external disturbance, which is easy to cause suspension fluctuation and instability. To improve the suspension stability and vibration suppression of the high-speed maglev train under aerodynamic load and impact, we design a siding mode controller introducing the primary suspension's deformation to replace the aerodynamic load on the electromagnet. Furthermore, we establish the train's dynamic simulation model with three vehicles and compare the designed controller and the PID controller for their performance in controlling the model suspension stability in the presence of the train operating in open air. Simulation results show that the sliding mode control (SMC) method proposed in this paper can effectively restrain the electromagnet fluctuation of the train under aerodynamic loads

Further analysis of the near-plug gas flow conditions in micro gas-solid fluidized beds

This work presents a theoretical analysis of the near-plug gas flow conditions in micro gas-solid fluidized beds based on the simple one-dimensional dispersion model. The analysis is validated by comparison with the experimental results reported in the literature. It concludes that gas flows can be considered near-plug flow only when: 1) the gas RTD curve is symmetrically shaped; 2) the product of RTD peak height E(t)(h) and variance sigma(t) (i.e., E(t)(h)sigma(t)) approximates 0.4; and 3) E(t)h is greater than 1.0 s(-1) (dimensionless E-theta,E-max > 2.82) or sigma(2)(t) 0.02). This work further improves the criterion for the near-plug flow of gas in micro fluidized beds originally proposed by Geng et al. (CEJ, 351 (2018) 110-118).(C) 2022 Elsevier B.V. All rights reserved

Further analysis of the near-plug gas flow conditions in micro gas-solid fluidized beds

This work presents a theoretical analysis of the near-plug gas flow conditions in micro gas-solid fluidized beds based on the simple one-dimensional dispersion model. The analysis is validated by comparison with the experimental results reported in the literature. It concludes that gas flows can be considered near-plug flow only when: 1) the gas RTD curve is symmetrically shaped; 2) the product of RTD peak height E(t)(h) and variance sigma(t) (i.e., E(t)(h)sigma(t)) approximates 0.4; and 3) E(t)h is greater than 1.0 s(-1) (dimensionless E-theta,E-max > 2.82) or sigma(2)(t) 0.02). This work further improves the criterion for the near-plug flow of gas in micro fluidized beds originally proposed by Geng et al. (CEJ, 351 (2018) 110-118).(C) 2022 Elsevier B.V. All rights reserved

A Review on the Reaction Mechanism of Hydrodesulfurization and Hydrodenitrogenation in Heavy Oil Upgrading

The future of fuel supply will undoubtedly involve the utilization of heavy crude oils, including those from nonconventional sources, such as bitumen and oil shale. Because of their dense nature and poor compositional characteristics, heavy oils cannot be admitted straightly as refinery feeds, since the direct processing of such oils hardly produces engine fuels of commercial standard. The currently available refinery setups also require substantial retrofitting in order to process such heavy feeds. Thus, heavy oils must undergo an initial upgrading called hydrotreatment (HDT) by which the feeds are converted to qualified fuel oils or synthetic crude (syncrude) for easy handling. Removing the considerable amount of sulfur (S) and nitrogen (N) compounds present in the heavy crude oils selectively by hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), respectively, is among the most critical and challenging aspects of the upgrading. However, the mechanism of these two reactions, in relation to different catalytic sites, temperature, pressure, and other operation variables, is not fully understood or well-documented. By analyzing the possible reaction routes involved in S and N removal by HDT, this review sets to bridge the gap that has been left void for a long period of time, to serve as a guide for innovative heavy crude oil upgrading technologies. It finally reports the current challenges impeding the speedy inclusion of heavy crude oils into the global oil supply stream, and proffer perspective solutions together with future research trends