| 1. |
- Cui, Shaohua, et al.
(författare)
-
Adaptive Collision-Free Trajectory Tracking Control for String Stable Bidirectional Platoons
- 2023
-
Ingår i: IEEE Transactions on Intelligent Transportation Systems. - 1524-9050 .- 1558-0016. ; 24:11, s. 12141-12153
-
Tidskriftsartikel (refereegranskat)abstract
- Autonomous vehicle (AV) platoons, especially those with the bidirectional communication topology, have significant practical value, as they not only increase link capacity and reduce vehicle energy consumption, but also reduce the consumption of communication resources. Small gaps between AVs in a platoon easily lead to emergency braking or even collisions between consecutive AVs. This paper applies barrier Lyapunov functions to collision avoidance between AVs in a bidirectional platoon during trajectory tracking. Based on backstepping technique, an adaptive collision-free platoon trajectory tracking control algorithm is developed to distributedly design control laws for each AV in the platoon. The control algorithm does not need to introduce additional car-following models to simulate AV driving, and only needs to integrate the position trajectories of consecutive AVs to avoid inter-vehicle collisions. Two sign functions are introduced into the control laws of each AV to ensure strong string stability for bidirectional AV platoons. Moreover, uncertainties and external disturbances in vehicle motion are effectively compensated by introducing adaptation laws. Strong string stability is rigorously proved. CarSIM-based comparison simulations verify the effectiveness of the proposed control algorithm in avoiding inter-vehicle collisions, compensating for uncertainties in vehicle motion, and suppressing the amplification of spacing errors along the platoon.
|
|
| 2. |
- Cui, Shaohua, 1995, et al.
(författare)
-
Delay-throughput tradeoffs for signalized networks with finite queue capacity
- 2024
-
Ingår i: Transportation Research Part B: Methodological. - 0191-2615. ; 180
-
Tidskriftsartikel (refereegranskat)abstract
- Network-level adaptive signal control is an effective way to reduce delay and increase network throughput. However, in the face of asymmetric exogenous demand, the increase of network performance via adaptive signal control alone is at the expense of service fairness (i.e., phase actuation fairness and network resource utilization fairness). In addition, for oversaturated networks, arbitrary adaptive signal control seems to have little effect on improving network performance. Therefore, under the assumption that the mean routing proportions/turn ratios of vehicles at intersections are fixed, this study investigates the problem of optimally allocating input rates to entry links and simultaneously finding a stabilizing signal control policy with phase fairness. We model the stochastic optimization problem of maximizing network throughput subject to network stability (i.e., all queue lengths have finite means) and average phase actuation constraints to bridge the gap between stochastic network stability control and convex optimization. Moreover, we further propose a micro-level joint admission and bounded signal control algorithm to achieve network stability and throughput optimization simultaneously. Joint control is implemented in a fully decomposed and distributed manner. For any arrival rate, joint control provably achieves network throughput within O(1/V) of optimality while trading off average delay with O(V), where V is an adjusted control parameter. Through a comparative simulation of a real network with 256 O-D pairs, the proposed joint control keeps network throughput at maximum, guarantees service fairness, and fully utilizes network capacity (i.e., increases network throughput by 17.54%).
|
|
| 3. |
- Cui, Shaohua, et al.
(författare)
-
Temporal Finite-Time Adaptation in Controlling Quantized Nonlinear Systems Amidst Time-Varying Output Constraints
- 2024
-
Ingår i: IEEE Transactions on Automation Science and Engineering. - 1558-3783 .- 1545-5955. ; In Press
-
Tidskriftsartikel (refereegranskat)abstract
- Using the backstepping technique, this paper formulates innovative adaptive finite-time stabilizing controllers for uncertain nonlinear systems featuring nonuniform input quantization and asymmetric, time-varying output constraints. These novel controllers leverage the consistent characteristics of both hysteresis quantizers and logarithmic quantizers. Quantization errors, when consistent, become unbounded and contingent on control input, rendering them incompatible with the growth conditions of nonlinear systems. Consequently, the developed adaptive controllers eliminate the reliance on growth conditions, effectively addressing the impact of unbounded quantization errors on finite-time stability. This adaptability allows the controllers to function effectively with systems employing either hysteresis quantizers or logarithmic quantizers. The paper establishes the convergence of these controllers through the finite-time Lyapunov stability theorem. It also provides a comprehensive guideline for tuning settling time, enabling fine-grained control over finite-time convergence and adjustable tracking error performance. Additionally, the controllers rigorously maintain system output within predefined limits. Their effectiveness and low computational burden are demonstrated through three comparative numerical simulations and a practical simulation in collision-free trajectory tracking control of an autonomous vehicle platoon using the vehicle motion software CarSim. These simulations confirm the advanced performance of the adaptive controllers. Note to Practitioners—This paper introduces an innovative approach to control uncertain nonlinear systems encountering intricate input quantization and output constraints. Employing the sophisticated backstepping technique, the authors present adaptive finite-time-stabilizing controllers engineered to address nonuniform input quantization and asymmetric, time-varying output restrictions. What distinguishes these controllers is their reliance on the consistent behavior exhibited by hysteresis and logarithmic quantizers. This unique feature equips them to effectively counteract unbounded quantization errors influenced by control input. Most notably, these controllers eliminate the conventional growth conditions typically demanded by nonlinear systems. As a result, they extend their applicability to a broad spectrum of systems employing either hysteresis or logarithmic quantizers. The research also provides practitioners with a valuable guideline for precisely adjusting settling time. This enables the attainment of desired convergence rates while permitting adaptable tracking error performance. Additionally, these controllers guarantee that the system’s output adheres to predefined limits. The practical significance of this study is highlighted through three comparative numerical simulations and a real-world application simulation. This real-world simulation involves collision-free trajectory tracking control of an autonomous vehicle platoon, executed using the vehicle motion software CarSim. These simulations unequivocally demonstrate the effectiveness and low computational burden of the developed controllers, thereby establishing them as a valuable resource for practitioners facing complex control challenges in various domains.
|
|
| 4. |
- Liu, Jiale, et al.
(författare)
-
STING inhibitors sensitize platinum chemotherapy in ovarian cancer by inhibiting the CGAS-STING pathway in cancer-associated fibroblasts (CAFs)
- 2024
-
Ingår i: Cancer Letters. - : Elsevier. - 0304-3835 .- 1872-7980. ; 588
-
Tidskriftsartikel (refereegranskat)abstract
- Chemotherapy resistance in ovarian cancer hampers cure rates, with cancer-associated fibroblasts (CAFs) playing a pivotal role. Despite their known impact on cancer progression and chemotherapy resistance, the specific mechanism by which CAFs regulate the tumor inflammatory environment remains unclear. This study reveals that cisplatin facilitates DNA transfer from ovarian cancer cells to CAFs, activating the CGAS-STING-IFNB1 pathway in CAFs and promoting IFNB1 release. Consequently, this reinforces cancer cell resistance to platinum drugs. High STING expression in the tumor stroma was associated with a poor prognosis, while inhibiting STING expression enhanced ovarian cancer sensitivity. Understanding the relevance of the CGAS-STING pathway in CAFs for platinum resistance suggests targeting STING as a promising combination therapy for ovarian cancer, providing potential avenues for improved treatment outcomes.
|
|
| 5. |
- Liu, Yuwei, et al.
(författare)
-
The effects of fermented rye products on gut microbiota and their association with metabolic factors in Chinese adults : an explorative study
- 2021
-
Ingår i: Food & Function. - : Royal Society of Chemistry. - 2042-6496 .- 2042-650X. ; 12:19, s. 9141-9150
-
Tidskriftsartikel (refereegranskat)abstract
- Rye is among the cereals with the highest content of dietary fibre. A high rye food intake has been associated with improved metabolic risk factors in some but not all observational and intervention studies. Whole-grain rye has also been suggested to affect the gut microbiota in individuals with metabolic syndrome. However, it is yet unclear to what extent effects on the gut microbiota mediate the beneficial metabolic responses of whole-grain rye intake. We hypothesized that a high intake of whole grain rye products containing fermented rye bran (FRB) vs. refined wheat based products (RW) could alter the gut microbiota and short-chain fatty acid (SCFA) composition towards a phenotype associated with beneficial metabolic effects in a population not used to such foods. For this purpose, we conducted a post hoc analysis of a 12-week randomized controlled trial in Chinese adults with Helicobacter pylori (HP) infection, with 53 participants consuming RW and 31 participants consuming FRB included in the analysis. Anthropometric measurements and fasting blood and fecal sample analyses as well as 13C-urea breath test were performed at baseline and after a 12-week intervention. At week 12, we observed a higher serum insulin concentration (P-value = 0.038) in the FRB group (n = 31) versus the RW group (n = 53), and this difference was corroborated with alterations in the genus-level relative abundances of the gut microbiota, represented by an increase in Romboutsia and a reduction in Bilophila in the FRB group (n = 22) versus the RW group (n = 46). Compared to the RW group (n = 53), fecal acetic acid concentration was significantly higher in the FRB group (n = 31) at week 12. We also found that fecal acetic and butyric acids positively, while isobutyric, isovaleric and 2-methylbutyric acids inversely, correlated with the gut Romboutsia level among all participants (n = 68) at week 12. We found positive correlations of fecal isobutyric, isovaleric and 2-methylbutyric acids with gut Bilophila (n = 68). In conclusion, our results suggest that the intake of high-fibre rye products could modify gut Romboutsia and Bilophila in a Chinese population with HP infection. These effects are paralleled with favorable modifications of the SCFA concentration and are associated with altered glycemic traits.
|
|
| 6. |
- Liu, Yuwei, et al.
(författare)
-
The effects of fermented rye products on gut microbiota and their association with metabolic factors in Chinese adults - an explorative study
- 2021
-
Ingår i: Food and Function. - : Royal Society of Chemistry (RSC). - 2042-6496 .- 2042-650X. ; 12:19, s. 9141-9150
-
Tidskriftsartikel (refereegranskat)abstract
- Rye is among the cereals with the highest content of dietary fibre. A high rye food intake has been associated with improved metabolic risk factors in some but not all observational and intervention studies. Whole-grain rye has also been suggested to affect the gut microbiota in individuals with metabolic syndrome. However, it is yet unclear to what extent effects on the gut microbiota mediate the beneficial metabolic responses of whole-grain rye intake. We hypothesized that a high intake of whole grain rye products containing fermented rye bran (FRB) vs. refined wheat based products (RW) could alter the gut microbiota and short-chain fatty acid (SCFA) composition towards a phenotype associated with beneficial metabolic effects in a population not used to such foods. For this purpose, we conducted a post hoc analysis of a 12-week randomized controlled trial in Chinese adults with Helicobacter pylori (HP) infection, with 53 participants consuming RW and 31 participants consuming FRB included in the analysis. Anthropometric measurements and fasting blood and fecal sample analyses as well as C-13-urea breath test were performed at baseline and after a 12-week intervention. At week 12, we observed a higher serum insulin concentration (P-value = 0.038) in the FRB group (n = 31) versus the RW group (n = 53), and this difference was corroborated with alterations in the genus-level relative abundances of the gut microbiota, represented by an increase in Romboutsia and a reduction in Bilophila in the FRB group (n = 22) versus the RW group (n = 46). Compared to the RW group (n = 53), fecal acetic acid concentration was significantly higher in the FRB group (n = 31) at week 12. We also found that fecal acetic and butyric acids positively, while isobutyric, isovaleric and 2-methylbutyric acids inversely, correlated with the gut Romboutsia level among all participants (n = 68) at week 12. We found positive correlations of fecal isobutyric, isovaleric and 2-methylbutyric acids with gut Bilophila (n = 68). In conclusion, our results suggest that the intake of high-fibre rye products could modify gut Romboutsia and Bilophila in a Chinese population with HP infection. These effects are paralleled with favorable modifications of the SCFA concentration and are associated with altered glycemic traits.
|
|
| 7. |
- Peng, Ningxin, et al.
(författare)
-
Platelet mitochondrial DNA methylation : A novel biomarker for myocardial infarction – A preliminary study
- 2023
-
Ingår i: International Journal of Cardiology. - 0167-5273.
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Platelet activation and thrombus formation play critical roles in the pathogenesis of myocardial infarction (MI). In addition to their role in energy production, platelet mitochondria also regulate cellular functions related to apoptosis, oxidative stress, and inflammation. Epigenetic modifications of platelet mitochondrial DNA (mtDNA) may influence platelet function and are believed to be an important factor in MI. Therefore, the aim of this study was to investigate the differences in platelet mtDNA methylation levels between MI patients and controls. Methods: The present study utilized propensity score matching to generate 45 multivariate matched apparently healthy controls for 45 patients with newly-onset acute MI. Platelet mtDNA methylation levels were assessed through bisulfite-PCR pyrosequencing and compared between the two groups, with further adjustments made in the sensitivity analysis. Results: Among the measured mitochondrial genes (MT-COX1, MT-COX2, MT-COX3, MT-ND5, MT-ATP6 and tRNA_Leu), patients with MI exhibited statistically significant differences in mtDNA methylation levels as compared to matched controls. Specifically, higher levels of mtDNA methylation were observed in MT-COX1, MT-COX3, and tRNA_Leu, while a lower level was observed in MT-ATP6 (all p < 0.0001). These results remained robust in the sensitivity analysis. Conclusion: Our study demonstrated significant variations in platelet mtDNA methylation levels between patients with MI and controls. Platelet mtDNA methylation may serve as a novel biomarker for MI. This observation also provided some insights into the etiology of MI.
|
|
| 8. |
- Wan, Lu Ming, et al.
(författare)
-
Heparanase Facilitates PMA-Induced Megakaryocytic Differentiation in K562 Cells via Interleukin 6/STAT3 Pathway
- 2020
-
Ingår i: Thrombosis and Haemostasis. - : GEORG THIEME VERLAG KG. - 0340-6245 .- 2567-689X. ; 120:4, s. 647-657
-
Tidskriftsartikel (refereegranskat)abstract
- Heparanase (HPSE) is an endo-beta-D-glucuronidase that cleaves heparan sulfate and hence participates in remodeling of the extracellular matrix, leading to release of cytokines that are immobilized by binding to heparan sulfate proteoglycans (HSPGs), and consequently activating signaling pathways. This function of HPSE is correlated to its expression level that is normally very low in majority of the tissues. Exceptionally, human platelets express high level of HPSE, suggesting a unique physiological role in this cell. Using K562 cell line, we found a progressive increase of HPSE during the megakaryocytic differentiation. Analysis of a series of megakaryocytic differentiation-related heparin-binding proteins (HBPs) in the cell culture medium revealed an exclusive positive correlation between the level of interleukin 6 (IL-6) and HPSE expression. IL-6 modulated megakaryocytic differentiation through activation of STAT3. Further, we demonstrated that overexpression of HPSE potentiates megakaryocytic differentiation, whereas elimination of HPSE led to a delayed differentiation. This function of HPSE is associated with its activity, as overexpression of inactive HPSE had no effect on IL-6 production and megakaryocytic differentiation. The role of HPSE is further supported by the observation in an umbilical cord blood CD34+ cells megakaryocytic differentiation model. Our data propose a novel role for HPSE in platelets production by a HPSE/IL-6/STAT3 positive feedback loop that specifically regulates megakaryocytes maturation.
|
|
| 9. |
- Xue, Kun, et al.
(författare)
-
Impact of a Fermented High-Fiber Rye Diet on Helicobacter pylori and Cardio-Metabolic Risk Factors : A Randomized Controlled Trial Among Helicobacter pylori-Positive Chinese Adults
- 2021
-
Ingår i: Frontiers in Nutrition. - : Progressive Frontiers Press. - 2296-861X. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Background: High dietary fiber intake has been associated with reduced risk of Helicobacter pylori infection and co-morbidities such as gastric cancer but also with reduced risk of cardiovascular disease. It has been suggested that fermented rye could affect Helicobacter pylori bacterial load and that high- fiber rye may be superior to wheat for improvement of several cardiometabolic risk factors, but few long-term interventions with high fiber rye foods have been conducted.Objective: To examine the effect of high-fiber wholegrain rye foods with added fermented rye bran vs. refined wheat on Helicobacter pylori infection and cardiometabolic risk markers in a Chinese population with a low habitual consumption of high fiber cereal foods.Design: A parallel dietary intervention was set up and 182 normal- or overweight men and women were randomized to consume wholegrain rye products containing fermented rye bran (FRB) or refined wheat (RW) for 12 weeks. Anthropometric measurements, fasting blood sample collection and 13C-urea breath test (13C-UBT) were performed at baseline and after 6 and 12 weeks of intervention as well as 12 weeks after the end of the intervention.Results: No difference between diets on Helicobacter pylori bacterial load measured by 13C-UBT breath test or in virulence factors of Helicobacter pylori in blood samples were found. Low density lipoprotein cholesterol (LDL-C) and high sensitivity C-reactive protein (hs-CRP) were significantly lower in the FRB group, compared to the RW group after 12 weeks of intervention. The intervention diets did not affect markers of glucose metabolism or insulin sensitivity.Conclusions: While the results of the present study did not support any effect of FRB on Helicobacter pylori bacterial load, beneficial effects on LDL-C and hs-CRP were clearly shown. This suggest that consumption of high fiber rye foods instead of refined wheat could be one strategy for primary prevention of cardiovascular disease.
|
|
| 10. |
|
|
