Self-adaptive modal control for time-varying structures

International audienceFor the past several years, modal controllers are widely studied and used in the field of vibration or vibro-acoustics control. They are efficient but not robust, because these methods involve a reconstructor based on a modal truncation. When the dynamic behavior of the structure change, the controller and reconstructor must be updated to cope with the changes in the structure behavior, in order to maintain both performance and robustness. A solution is adaptive control but this approach needs some specific information not generally available particularly in the case of undergone modifications. This paper deals with a self-adaptive modal control based on a real-time identifier, which avoid the need of specific information. The identifier permits to update the controller and the reconstructor according to the changes of modal characteristics of time-varying structures. A classical algorithm of identification is used to obtain a state space model with an unspecified state vector. Then, based on this model, a well adapted transformation is carried out to get the modal characteristics from the expression of complex modes, including the mode shapes. As a criterion of running identification, the value of "variance-accounted for" (VAF) is employed to carry out the identifier only when the initial or previous model is not enough exact. A Linear Quadratic Gaussian Algorithm is employed in such a way that the control and observer can be optimized according to the updated modal model. By this way, a self-adaptive modal control is completed and can demonstrate some smart properties. The proposed methodology is carried out on a simple but representative time-varying mechanical discrete structure. An inertia modification leads not only to low modal frequency shifts but also to inversion of a mode shape which is shown to lead to unstable configuration when control system is not 2 updated. The overall procedure will be described through simulations and performed for different operating conditions, which will prove that mode shapes have to be precisely determined and updated in the controller and observer to guarantee a robust modal control with high performance in spite of the changes of structure

Contrôle modal autoadaptatif de vibrations de structures évolutives

L allègement des structures imposé par les réductions de coût se traduit par des structures de plus en plus souples qui les rendent de plus en plus sensibles aux vibrations. Le contrôle des vibrations devient donc un enjeu majeur dans de nombreuses applications industrielles et les limites des matériaux imposent maintenant un recours au contrôle actif de plus en plus fréquent. L évolution des structures au cours du temps (viellisement, conditions aux limites, architecture, ) pose le problème de la robustesse du contrôle. Par ailleurs, l actionnement de plus en plus présent dans le domaine mécanique constitue à la fois une source supplémentaire de vibrations, mais aussi de contrôle et d évolution d architecture des structures. La thèse s intéresse au contrôle actif autoadaptatif des vibrations permettant de maintenir automatiquement la performance et la stabilité des structures évolutives. Il s agit donc de s affranchir de la connaissance des causes et des informations sur les évolutions. La méthode proposée s appuie sur un développement modal permettant de limiter le nombre de composants de contrôle et de cibler les modes à contrôler en limitant l énergie de contrôle. Ainsi, il est nécessaire de reconstruire les caractéristiques du modèle modal indispensables pour réactualiser le contrôle en figeant seulement une structure de modèle. S affranchissant à la fois des causes d évolution de la structure et utilisant seulement une structure de modèle, la méthode est généralisable à toute application en mécanique des structures. La méthode proposée, basée sur l utilisation d un identificateur exploitant à la fois excitation et réponse de la structure, prend en compte les limites imposées par le contrôleur. Le modèle constitue le lien qui doit être établi entre identificateur et contrôle pour permettre la réactualisation. Par ailleurs, un compromis entre l objectif d atténuation des vibrations et les performances de l identification est alors nécessaire du fait du couplage identification/contrôle apparaissant dans la boucle fermée. Ce compromis est également conditionné par le matériel utilisé. La méthode proposée est exploitée sur une structure discrète mettant en évidence une inversion de formes modales au cours de son évolution qui déstabilise un contrôle figé. Le choix opéré pour répondre aux différents compromis cités ci dessus a conduit à l utilisation d un contrôleur classique (LQG) et un identificateur basé sur la méthode des sous-espaces (N4SID). Cette application sur une structure simple a permis de caractériser un certain nombre de limites physiques : la bande passante, densité modale, vitesse d évolution, Le contrôle modal autoadaptatif proposé s avère robuste en performance et efficace lorsque la réactualisation est systématique. Une variante conditionnelle, toujours basée sur l analyse de la réponse de la structure, est enfin proposée pour optimiser le processus de réactualisation afin de suivre plus efficacement les évolutions.The lightness of structure due to the reduction of cost results in some structures which are more and more flexible. This flexibility makes these structures more sensitive to vibrations. The vibration control becomes an important issue in lots of industrial applications, and now the limitation of materials imposes a requirement of active control more and more frequently.The change of time-varying structure(ageing effect, boundaries conditions, architecture of structure etc)brings the robust problem of control.Further more,the action of device which emerges more and more frequently in mechanical fields introduces not only an additional cause of vibrations,but also a source of control and a source for changing the architecture of structures.The thesis focuses on self-adaptive active control of vibration which permits to keep up automatically the performance and stability of the time-varying structures.So it needs to overcome the knowing about cause and information on the changes.The proposed method relies on a development of modal technology which permits to limit the amount of component in control system and to target on the modes which need to be controlled.So the energy of control is limited. Further more,it needs to reconstruct the characteristics of modal model which are indispensable for updating the control.In this case, only the structure of model is fixed.Overcoming the knowing about cause of change in the structure and using only the structure of model, this method can be generalized for all applications in mechanical structures.The proposed method is based on the utilization of an identifier which uses both the excitation and response of the structure.And this method considers the limitations induced by the controller.The model forms le link which should be established between the identifier and the controller for allowing the updating. Further more, a compromise between the objective of reducing vibrations and the performance of identification is necessary due to the coupling effect of identification/control which appears in the closed-loop. This compromise is also conditioned by the used equipments.The proposed method is carried out on a discrete time-varying structure for showing an inversion of mode shape during its change. This inversion of mode shape destabilises a fixed control system. The operated choices for responding the different previous quoted compromise lead to a classic controller (LQG) and an identifier based on the subspace method (N4SID).This application on a simple structure permitted to characterise some physical limitation: the bandwidth, the modal density and the velocity of change The proposed self-adaptive modal control is proved to be robust in terms of performance and be efficient when the updating is systematical. Always based on the analysis of the response of the structure, a conditional variant is finally proposed for optimizing the process of updating in order to follow the change more efficiently.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocVILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

Hepatocyte nuclear receptor SHP suppresses inflammation and fibrosis in a mouse model of nonalcoholic steatohepatitis

This research was originally published in the Journal of Biological Chemistry. An Zou, Nancy Magee, Fengyan Deng, Sarah Lehn, Cuncong Zhong, Yuxia Zhang. Hepatocyte nuclear receptor SHP suppresses inflammation and fibrosis in a mouse model of nonalcoholic steatohepatitis. J. Biol. Chem. 2018; Vol:pp-pp. © The American Society for Biochemistry and Molecular Biology. This work is licensed under a Creative Commons Attribution 4.0 International License.Nonalcoholic fatty liver disease (NAFLD) is a burgeoning health problem worldwide, ranging from nonalcoholic fatty liver (NAFL, steatosis without hepatocellular injury) to the more aggressive nonalcoholic steatohepatitis (NASH, steatosis with ballooning, inflammation, or fibrosis). Although many studies have greatly contributed to the elucidation of NAFLD pathogenesis, the disease progression from NAFL to NASH remains incompletely understood. Nuclear receptor small heterodimer partner (Nr0b2, SHP) is a transcriptional regulator critical for the regulation of bile acid, glucose, and lipid metabolism. Here, we show that SHP levels are decreased in the livers of patients with NASH and in diet-induced mouse NASH. Exposing primary mouse hepatocytes to palmitic acid and lipopolysaccharide in vitro, we demonstrated that the suppression of Shp expression in hepatocytes is due to c-Jun N-terminal kinase (JNK) activation, which stimulates c-Jun–mediated transcriptional repression of Shp. Interestingly, in vivo induction of hepatocyte-specific SHP in steatotic mouse liver ameliorated NASH progression by attenuating liver inflammation and fibrosis, but not steatosis. Moreover, a key mechanism linking the anti-inflammatory role of hepatocyte-specific SHP expression to inflammation involved SHP-induced suppression of NF-κB p65-mediated induction of chemokine (C–C motif) ligand 2 (CCL2), which activates macrophage proinflammatory polarization and migration. In summary, our results indicate that a JNK/SHP/NF-κB/CCL2 regulatory network controls communications between hepatocytes and macrophages and contributes to the disease progression from NAFL to NASH. Our findings may benefit the development of new management or prevention strategies for NASH

Anticancer effects of licochalcones: A review of the mechanisms

Cancer is a disease with a high fatality rate representing a serious threat to human health. Researchers have tried to identify effective anticancer drugs. Licorice is a widely used traditional Chinese medicine with various pharmacological properties, and licorice-derived flavonoids include licochalcones like licochalcone A, licochalcone B, licochalcone C, licochalcone D, licochalcone E, and licochalcone H. By regulating the expression in multiple signaling pathways such as the EGFR/ERK, PI3K/Akt/mTOR, p38/JNK, JAK2/STAT3, MEK/ERK, Wnt/β-catenin, and MKK4/JNK pathways, and their downstream proteins, licochalcones can activate the mitochondrial apoptosis pathway and death receptor pathway, promote autophagy-related protein expression, inhibit the expression of cell cycle proteins and angiogenesis factors, regulate autophagy and apoptosis, and inhibit the proliferation, migration, and invasion of cancer cells. Among the licochalcones, the largest number of studies examined licochalcone A, far more than other licochalcones. Licochalcone A not only has prominent anticancer effects but also can be used to inhibit the efflux of antineoplastic drugs from cancer cells. Moreover, derivatives of licochalcone A exhibit strong antitumor effects. Currently, most results of the anticancer effects of licochalcones are derived from cell experiments. Thus, more clinical studies are needed to confirm the antineoplastic effects of licochalcones

CagA-positive Helicobacter pylori may promote and aggravate scrub typhus

Helicobacter pylori (H. pylori) infection may alter the host’s resistance to tsutsugamushi disease pathogens through the Th1 immune response, leading to potential synergistic pathogenic effects. A total of 117 scrub typhus cases at Beihai People’s Hospital and affiliated hospitals of Youjiang University for Nationalities and Medical Sciences were studied from January to December 2022, alongside 130 healthy individuals forming the control group. All participants underwent serum H. pylori antibody testing. The prevalence of H. pylori infection was significantly higher among scrub typhus patients (89.7%) compared to healthy individuals (54.6%) (p < 0.05). Moreover, type I H. pylori infection was notably more prevalent in scrub typhus cases (67.5%) compared to healthy individuals (30%) (p < 0.05). Multifactorial analysis demonstrated type I H. pylori infection as an independent risk factor for scrub typhus (adjusted odds ratio: 2.407, 95% confidence interval: 1.249–4.64, p = 0.009). Among scrub typhus patients with multiple organ damage, the prevalence of type I H. pylori infection was significantly higher (50.6%) than type II H. pylori infection (15.4%) (χ2 = 4.735, p = 0.030). These results highlight a higher incidence of H. pylori infection in scrub typhus patients compared to the healthy population. Additionally, type I H. pylori strain emerged as an independent risk factor for scrub typhus development. Moreover, individuals infected with type I H. pylori are more susceptible to multiple organ damage. These findings suggest a potential role of H. pylori carrying the CagA gene in promoting and exacerbating scrub typhus

Identification of Genome-Wide Variations among Three Elite Restorer Lines for Hybrid-Rice

Rice restorer lines play an important role in three-line hybrid rice production. Previous research based on molecular tagging has suggested that the restorer lines used widely today have narrow genetic backgrounds. However, patterns of genetic variation at a genome-wide scale in these restorer lines remain largely unknown. The present study performed re-sequencing and genome-wide variation analysis of three important representative restorer lines, namely, IR24, MH63, and SH527, using the Solexa sequencing technology. With the genomic sequence of the Indica cultivar 9311 as the reference, the following genetic features were identified: 267,383 single-nucleotide polymorphisms (SNPs), 52,847 insertion/deletion polymorphisms (InDels), and 3,286 structural variations (SVs) in the genome of IR24; 288,764 SNPs, 59,658 InDels, and 3,226 SVs in MH63; and 259,862 SNPs, 55,500 InDels, and 3,127 SVs in SH527. Variations between samples were also determined by comparative analysis of authentic collections of SNPs, InDels, and SVs, and were functionally annotated. Furthermore, variations in several important genes were also surveyed by alignment analysis in these lines. Our results suggest that genetic variations among these lines, although far lower than those reported in the landrace population, are greater than expected, indicating a complicated genetic basis for the phenotypic diversity of the restorer lines. Identification of genome-wide variation and pattern analysis among the restorer lines will facilitate future genetic studies and the molecular improvement of hybrid rice

Self-adaptive modal control of vibrations for time-varying structures

L’allègement des structures imposé par les réductions de coût se traduit par des structures de plus en plus souples qui les rendent de plus en plus sensibles aux vibrations. Le contrôle des vibrations devient donc un enjeu majeur dans de nombreuses applications industrielles et les limites des matériaux imposent maintenant un recours au contrôle actif de plus en plus fréquent. L’évolution des structures au cours du temps (viellisement, conditions aux limites, architecture, …) pose le problème de la robustesse du contrôle. Par ailleurs, l’actionnement de plus en plus présent dans le domaine mécanique constitue à la fois une source supplémentaire de vibrations, mais aussi de contrôle et d’évolution d’architecture des structures. La thèse s’intéresse au contrôle actif autoadaptatif des vibrations permettant de maintenir automatiquement la performance et la stabilité des structures évolutives. Il s’agit donc de s’affranchir de la connaissance des causes et des informations sur les évolutions. La méthode proposée s’appuie sur un développement modal permettant de limiter le nombre de composants de contrôle et de cibler les modes à contrôler en limitant l’énergie de contrôle. Ainsi, il est nécessaire de reconstruire les caractéristiques du modèle modal indispensables pour réactualiser le contrôle en figeant seulement une structure de modèle. S’affranchissant à la fois des causes d’évolution de la structure et utilisant seulement une structure de modèle, la méthode est généralisable à toute application en mécanique des structures. La méthode proposée, basée sur l’utilisation d’un identificateur exploitant à la fois excitation et réponse de la structure, prend en compte les limites imposées par le contrôleur. Le modèle constitue le lien qui doit être établi entre identificateur et contrôle pour permettre la réactualisation. Par ailleurs, un compromis entre l’objectif d’atténuation des vibrations et les performances de l’identification est alors nécessaire du fait du couplage identification/contrôle apparaissant dans la boucle fermée. Ce compromis est également conditionné par le matériel utilisé. La méthode proposée est exploitée sur une structure discrète mettant en évidence une inversion de formes modales au cours de son évolution qui déstabilise un contrôle figé. Le choix opéré pour répondre aux différents compromis cités ci dessus a conduit à l’utilisation d’un contrôleur classique (LQG) et un identificateur basé sur la méthode des sous-espaces (N4SID). Cette application sur une structure simple a permis de caractériser un certain nombre de limites physiques : la bande passante, densité modale, vitesse d’évolution, Le contrôle modal autoadaptatif proposé s’avère robuste en performance et efficace lorsque la réactualisation est systématique. Une variante conditionnelle, toujours basée sur l’analyse de la réponse de la structure, est enfin proposée pour optimiser le processus de réactualisation afin de suivre plus efficacement les évolutions.The lightness of structure due to the reduction of cost results in some structures which are more and more flexible. This flexibility makes these structures more sensitive to vibrations. The vibration control becomes an important issue in lots of industrial applications, and now the limitation of materials imposes a requirement of active control more and more frequently.The change of time-varying structure(ageing effect, boundaries conditions, architecture of structure etc)brings the robust problem of control.Further more,the action of device which emerges more and more frequently in mechanical fields introduces not only an additional cause of vibrations,but also a source of control and a source for changing the architecture of structures.The thesis focuses on self-adaptive active control of vibration which permits to keep up automatically the performance and stability of the time-varying structures.So it needs to overcome the knowing about cause and information on the changes.The proposed method relies on a development of modal technology which permits to limit the amount of component in control system and to target on the modes which need to be controlled.So the energy of control is limited. Further more,it needs to reconstruct the characteristics of modal model which are indispensable for updating the control.In this case, only the structure of model is fixed.Overcoming the knowing about cause of change in the structure and using only the structure of model, this method can be generalized for all applications in mechanical structures.The proposed method is based on the utilization of an identifier which uses both the excitation and response of the structure.And this method considers the limitations induced by the controller.The model forms le link which should be established between the identifier and the controller for allowing the updating. Further more, a compromise between the objective of reducing vibrations and the performance of identification is necessary due to the coupling effect of identification/control which appears in the closed-loop. This compromise is also conditioned by the used equipments.The proposed method is carried out on a discrete time-varying structure for showing an inversion of mode shape during its change. This inversion of mode shape destabilises a fixed control system. The operated choices for responding the different previous quoted compromise lead to a classic controller (LQG) and an identifier based on the subspace method (N4SID).This application on a simple structure permitted to characterise some physical limitation: the bandwidth, the modal density and the velocity of change…The proposed self-adaptive modal control is proved to be robust in terms of performance and be efficient when the updating is systematical. Always based on the analysis of the response of the structure, a conditional variant is finally proposed for optimizing the process of updating in order to follow the change more efficiently

Contrôle modal autoadaptatif de vibrations de structures évolutives

The lightness of structure due to the reduction of cost results in some structures which are more and more flexible. This flexibility makes these structures more sensitive to vibrations. The vibration control becomes an important issue in lots of industrial applications, and now the limitation of materials imposes a requirement of active control more and more frequently.The change of time-varying structure(ageing effect, boundaries conditions, architecture of structure etc)brings the robust problem of control.Further more,the action of device which emerges more and more frequently in mechanical fields introduces not only an additional cause of vibrations,but also a source of control and a source for changing the architecture of structures.The thesis focuses on self-adaptive active control of vibration which permits to keep up automatically the performance and stability of the time-varying structures.So it needs to overcome the knowing about cause and information on the changes.The proposed method relies on a development of modal technology which permits to limit the amount of component in control system and to target on the modes which need to be controlled.So the energy of control is limited. Further more,it needs to reconstruct the characteristics of modal model which are indispensable for updating the control.In this case, only the structure of model is fixed.Overcoming the knowing about cause of change in the structure and using only the structure of model, this method can be generalized for all applications in mechanical structures.The proposed method is based on the utilization of an identifier which uses both the excitation and response of the structure.And this method considers the limitations induced by the controller.The model forms le link which should be established between the identifier and the controller for allowing the updating. Further more, a compromise between the objective of reducing vibrations and the performance of identification is necessary due to the coupling effect of identification/control which appears in the closed-loop. This compromise is also conditioned by the used equipments.The proposed method is carried out on a discrete time-varying structure for showing an inversion of mode shape during its change. This inversion of mode shape destabilises a fixed control system. The operated choices for responding the different previous quoted compromise lead to a classic controller (LQG) and an identifier based on the subspace method (N4SID).This application on a simple structure permitted to characterise some physical limitation: the bandwidth, the modal density and the velocity of change…The proposed self-adaptive modal control is proved to be robust in terms of performance and be efficient when the updating is systematical. Always based on the analysis of the response of the structure, a conditional variant is finally proposed for optimizing the process of updating in order to follow the change more efficiently.L’allègement des structures imposé par les réductions de coût se traduit par des structures de plus en plus souples qui les rendent de plus en plus sensibles aux vibrations. Le contrôle des vibrations devient donc un enjeu majeur dans de nombreuses applications industrielles et les limites des matériaux imposent maintenant un recours au contrôle actif de plus en plus fréquent. L’évolution des structures au cours du temps (viellisement, conditions aux limites, architecture, …) pose le problème de la robustesse du contrôle. Par ailleurs, l’actionnement de plus en plus présent dans le domaine mécanique constitue à la fois une source supplémentaire de vibrations, mais aussi de contrôle et d’évolution d’architecture des structures. La thèse s’intéresse au contrôle actif autoadaptatif des vibrations permettant de maintenir automatiquement la performance et la stabilité des structures évolutives. Il s’agit donc de s’affranchir de la connaissance des causes et des informations sur les évolutions. La méthode proposée s’appuie sur un développement modal permettant de limiter le nombre de composants de contrôle et de cibler les modes à contrôler en limitant l’énergie de contrôle. Ainsi, il est nécessaire de reconstruire les caractéristiques du modèle modal indispensables pour réactualiser le contrôle en figeant seulement une structure de modèle. S’affranchissant à la fois des causes d’évolution de la structure et utilisant seulement une structure de modèle, la méthode est généralisable à toute application en mécanique des structures. La méthode proposée, basée sur l’utilisation d’un identificateur exploitant à la fois excitation et réponse de la structure, prend en compte les limites imposées par le contrôleur. Le modèle constitue le lien qui doit être établi entre identificateur et contrôle pour permettre la réactualisation. Par ailleurs, un compromis entre l’objectif d’atténuation des vibrations et les performances de l’identification est alors nécessaire du fait du couplage identification/contrôle apparaissant dans la boucle fermée. Ce compromis est également conditionné par le matériel utilisé. La méthode proposée est exploitée sur une structure discrète mettant en évidence une inversion de formes modales au cours de son évolution qui déstabilise un contrôle figé. Le choix opéré pour répondre aux différents compromis cités ci dessus a conduit à l’utilisation d’un contrôleur classique (LQG) et un identificateur basé sur la méthode des sous-espaces (N4SID). Cette application sur une structure simple a permis de caractériser un certain nombre de limites physiques : la bande passante, densité modale, vitesse d’évolution, Le contrôle modal autoadaptatif proposé s’avère robuste en performance et efficace lorsque la réactualisation est systématique. Une variante conditionnelle, toujours basée sur l’analyse de la réponse de la structure, est enfin proposée pour optimiser le processus de réactualisation afin de suivre plus efficacement les évolutions

A review on exosome-based cancer therapy

Cancer is one of the leading causes of mortality and morbidity globally. Many types of cancer treatments have been developed, such as chemotherapy, surgery, radiotherapy, and immunotherapy. However, these therapies can also kill healthy cells and lead to severe side effects. Therefore, scientists are looking for new strategies to eliminate cancerous cells specifically. Exosomes, nanometer-sized lipid bilayer-enclosed vesicles secreted from various cell types, exist in nearly all body fluids, including blood, breast milk, saliva, urine, bile, pancreatic juice, cerebrospinal, and peritoneal fluids. They carry myriad donor cell-derived bioactive molecules such as proteins, lipids, and RNAs (including microRNA and lncRNA) and can deliver them to both nearby and distant recipient cells. Due to these characteristics, exosomes have attracted great interest in cancer treatment (especially serving as a biological carrier for some drugs, microRNA, lncRNA, inhibitors, and antibodies). In this paper, we will review the current knowledge of exosome therapeutic applications in cancer

Decoding the role of extracellular vesicles in liver diseases

Cell-to-cell communication is a fascinating process that is essential for maintaining tissue and whole-body homeostasis. Extracellular vesicles (EVs) are cell-derived membrane-bound nanoparticles that are a means of communication between cells. Accumulating evidence indicates that EVs can render either beneficial or harmful outcomes, depending on the specific cargos (e.g., proteins, lipids, RNAs) transferred between cells. EVs also have great value as diagnostic and prognostic markers of disease because they are present in a variety of biological fluids and carry bioactive molecules from their cells or tissues of origin. Liver cells can both release and receive EVs derived from other cells and emerging evidence indicates that liver EVs play important roles in the pathogenesis of various liver diseases, including liver cancer, viral hepatitis, non-alcoholic fatty liver disease, and alcoholic liver disease. This review provides an overview of the biogenesis and secretion of EVs and summarizes the most recent advances in understanding the role of EVs in liver physiology and diseases. Additionally, we discuss potential applications of liver EVs as biomarkers and in therapeutic approaches to treat liver diseases. Keywords: Extracellular vesicles (EVs), Liver, Disease, Metabolism, Biomarke