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1.
J Immunol Res ; 2024: 9527268, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38966668

RESUMO

Aberrant accumulation of circulating follicular helper T cells (cTfh) has been found in the peripheral blood mononuclear cells (PBMCs) of Graves' disease (GD) patients. However, the underlying mechanism that contributes to the imbalance of cTfh cells remains unknown. Previously, studies described a GD-related circular RNAs (circRNAs)-circZNF644 that might be associated with cTfh cells. This study aimed to investigate the role of circZNF644 on cTfh cells in GD patients. Here, we found that circZNF644 was highly stable expression in the PBMCs of GD patients, which was positively correlated with the serum levels of TSH receptor autoantibodies (TRAb). Knockdown of circZNF644 caused a reduction of the proportion of cTfh cells in vitro. Mechanistically, circZNF644 served as a ceRNA for miR-29a-3p to promote ICOS expression, resulting in increased cTfh cells. In the PBMCs of GD patients, circZNF644 expression was positively correlated with ICOS expression and the percentage of cTfh cells, but negatively related to miR-29a-3p expression. Additionally, a strong relationship between circZNF644 and IL-21 was revealed in GD patients, and silencing of circZNF644 inhibited IL-21 expression. Our study elucidated that elevated expression of circZNF644 is a key feature in the development of GD and may contribute to the pathogenic role of cTfh cells in GD.


Assuntos
Doença de Graves , MicroRNAs , RNA Circular , Células T Auxiliares Foliculares , Humanos , Doença de Graves/genética , Doença de Graves/imunologia , RNA Circular/genética , Masculino , Feminino , Células T Auxiliares Foliculares/imunologia , Adulto , MicroRNAs/genética , Pessoa de Meia-Idade , Autoanticorpos/imunologia , Autoanticorpos/sangue , Proteína Coestimuladora de Linfócitos T Induzíveis/metabolismo , Proteína Coestimuladora de Linfócitos T Induzíveis/genética , Interleucinas/genética , Interleucinas/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Regulação da Expressão Gênica
2.
Heliyon ; 10(12): e33093, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38988528

RESUMO

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is a critical innate immune pathway primarily due to its vital DNA sensing mechanism in pathogen defence. Recent research advances have shown that excessive activation or damage to the cGAS-STING pathway can exacerbate chronic inflammatory responses, playing a significant role in metabolic dysfunction and aging, leading to the development of related diseases such as obesity, osteoporosis, and neurodegenerative diseases. This article reviews the structure and biological functions of the cGAS-STING signaling pathway and discusses in detail how this pathway regulates the occurrence and development of metabolic and age-related diseases. Additionally, this article introduces potential small molecule drugs targeting cGAS and STING, aiming to provide new research perspectives for studying the pathogenesis and treatment of metabolic-related diseases.

3.
Int Immunopharmacol ; 137: 112374, 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-38851162

RESUMO

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a neurological disorder, characterized by cognitive deficits as one of its vital features. The nucleotide-binding oligomerization domain-like receptor (NLRP3) inflammasome is a key contributor to neuroinflammation and cognitive deficits in neurological diseases. However, the underlying mechanism of anti-NMDAR encephalitis remains unclear, and the biological function of the NLRP3 inflammasome in this condition has not been elucidated. In this study, a mouse model of anti-NMDAR encephalitis was induced by active immunization with the GluN1356-385 peptide (NEA model). The NLRP3 inflammasome in the hippocampus and temporal cortex was investigated using real-time quantitative PCR (RT-qPCR), western blotting, and immunofluorescence staining. The impact of MCC950 on cognitive function and NLRP3 inflammation was assessed. Confocal immunofluorescence staining and Sholl analysis were employed to examine the function and morphology of microglia. In the current study, we discovered overactivation of the NLRP3 inflammasome and an enhanced inflammatory response in the NEA model, particularly in the hippocampus and temporal cortex. Furthermore, significant cognitive dysfunction was observed in the NEA model. While, MCC950, a selective inhibitor of the NLRP3 inflammasome, sharply attenuated the inflammatory response in mice, leading to mitigated cognitive deficits of mice and more regular arrangements of neurons and reduced number of hyperchromatic cells were also observed in the hippocampus area. In addition, we found that the excess elevation of NLRP3 inflammasome was mainly expressed in microglia accompanied with the overactivation of microglia, while MCC950 treatment significantly inhibited the increased number and activated morphological changes of microglia in the NEA model. Altogether, our study reveals the vital role of overactivated NLRP3 signaling pathway in aggravating the inflammatory response and cognitive deficits and the potential protective effect of MCC950 in anti-NMDAR encephalitis. Thus, MCC950 represents a promising strategy for anti-inflammation in anti-NMDAR encephalitis and our study lays a theoretical foundation for it to become a clinically targeted drug.


Assuntos
Encefalite Antirreceptor de N-Metil-D-Aspartato , Disfunção Cognitiva , Modelos Animais de Doenças , Hipocampo , Indenos , Inflamassomos , Microglia , Proteína 3 que Contém Domínio de Pirina da Família NLR , Sulfonamidas , Animais , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/antagonistas & inibidores , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/imunologia , Disfunção Cognitiva/etiologia , Inflamassomos/metabolismo , Inflamassomos/antagonistas & inibidores , Inflamassomos/imunologia , Camundongos , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Hipocampo/metabolismo , Hipocampo/imunologia , Encefalite Antirreceptor de N-Metil-D-Aspartato/imunologia , Encefalite Antirreceptor de N-Metil-D-Aspartato/tratamento farmacológico , Indenos/uso terapêutico , Sulfonamidas/uso terapêutico , Sulfonamidas/farmacologia , Microglia/efeitos dos fármacos , Microglia/imunologia , Furanos/uso terapêutico , Furanos/farmacologia , Sulfonas/uso terapêutico , Sulfonas/farmacologia , Camundongos Endogâmicos C57BL , Feminino , Compostos Heterocíclicos de 4 ou mais Anéis/uso terapêutico , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Masculino , Lobo Temporal/patologia
5.
Biomed Pharmacother ; 177: 116966, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38906018

RESUMO

In recent years, there has been a significant increase in the incidence of metabolic-associated fatty liver disease (MAFLD), which has been attributed to the increasing prevalence of type 2 diabetes mellitus (T2DM) and obesity. MAFLD affects more than one-third of adults worldwide, making it the most prevalent liver disease globally. Moreover, MAFLD is considered a significant risk factor for hepatocellular carcinoma (HCC), with MAFLD-related HCC cases increasing. Approximately 1 in 6 HCC patients are believed to have MAFLD, and nearly 40 % of these HCC patients do not progress to cirrhosis, indicating direct transformation from MAFLD to HCC. N6-methyladenosine (m6A) is commonly distributed in eukaryotic mRNA and plays a crucial role in normal development and disease progression, particularly in tumors. Numerous studies have highlighted the close association between abnormal m6A modification and cellular metabolic alterations, underscoring its importance in the onset and progression of MAFLD. However, the specific impact of m6A modification on the progression of MAFLD to HCC remains unclear. Can targeting m6A effectively halt the progression of MAFLD-related HCC? In this review, we investigated the pivotal role of abnormal m6A modification in the transition from MAFLD to HCC, explored the potential of m6A modification as a therapeutic target for MAFLD-related HCC, and proposed possible directions for future investigations.

6.
Artigo em Inglês | MEDLINE | ID: mdl-38743900

RESUMO

Objective: This study aims to evaluate the effects of hydrogen therapy on nerve function and tumor progression markers in glioma patients, focusing on the modulation of oxidative stress and cadherin expression to establish its potential as a complementary treatment. Methods: 100 glioma patients were enrolled and divided into two groups using the random number table: routine treatment (50) and hydrogen inhalation plus routine treatment (50). After 2 weeks of treatment, clinical curative effect, levels of nerve function indexes [national institute of health stroke scale (NIHSS), central nervous specific protein (S100ß), neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP)], oxidative stress indexes [malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT)] and E-cadherin before and after treatment, and occurrence of adverse reactions during treatment were compared between the two groups. Results: After treatment, the overall effect of the hydrogen inhalation group (90.00%) was significantly better than that of the conventional group (72.00%), which was statistically significant (P = .022). In terms of specific biomarkers, post-treatment levels of E-cadherin were elevated to 0.84±0.05 ng/mL in the hydrogen group compared to 0.72±0.06 ng/mL in the routine group. SOD and CAT levels rose to 63.21±5.36 U/L and 8.01±0.54 U/mL, respectively, versus 52.31±5.24 U/L and 5.25±0.59 U/mL in the routine group (P < .05 for both). Conversely, the NIHSS scores decreased significantly to 12.19±2.08 in the hydrogen group, compared to 16.92±2.23 in the routine group. Similarly, S100ß, NSE, GFAP, and MDA levels were found to be lower in the hydrogen group (0.41±0.09 µg/L, 8.24±1.64 ng/mL, 0.71±0.23 pg/mL, and 6.05±1.08 mmol/L respectively) than in the routine group (0.66±0.12 µg/L, 10.67±1.83 ng/mL, 0.93±0.29 pg/mL, and 7.21±1.12 mmol/L respectively) with P < .05 for all comparisons. The total incidence of adverse reactions was slightly lower in the hydrogen group (64.00%) compared to the routine group (68.00%), but this difference was not statistically significant (χ2=0.178, P = .673). Conclusion: Hydrogen inhalation therapy significantly enhances nerve function, reduces local oxidative stress levels, and increases E-cadherin levels in patients with brain glioma, suggesting its potential as an adjunct treatment. The findings underscore the therapy's role in enhancing patient recovery and guiding future research and treatment strategies.

7.
Nat Commun ; 15(1): 4162, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755139

RESUMO

The multibasic furin cleavage site at the S1/S2 boundary of the spike protein is a hallmark of SARS-CoV-2 and plays a crucial role in viral infection. However, the mechanism underlying furin activation and its regulation remain poorly understood. Here, we show that GalNAc-T3 and T7 jointly initiate clustered O-glycosylations in the furin cleavage site of the SARS-CoV-2 spike protein, which inhibit furin processing, suppress the incorporation of the spike protein into virus-like-particles and affect viral infection. Mechanistic analysis reveals that the assembly of the spike protein into virus-like particles relies on interactions between the furin-cleaved spike protein and the membrane protein of SARS-CoV-2, suggesting a possible mechanism for furin activation. Interestingly, mutations in the spike protein of the alpha and delta variants of the virus confer resistance against glycosylation by GalNAc-T3 and T7. In the omicron variant, additional mutations reverse this resistance, making the spike protein susceptible to glycosylation in vitro and sensitive to GalNAc-T3 and T7 expression in human lung cells. Our findings highlight the role of glycosylation as a defense mechanism employed by host cells against SARS-CoV-2 and shed light on the evolutionary interplay between the host and the virus.


Assuntos
COVID-19 , Furina , Mutação , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/química , Humanos , SARS-CoV-2/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Glicosilação , Furina/metabolismo , Furina/genética , COVID-19/virologia , COVID-19/metabolismo , Células HEK293 , N-Acetilgalactosaminiltransferases/metabolismo , N-Acetilgalactosaminiltransferases/genética , Animais , Chlorocebus aethiops , Polipeptídeo N-Acetilgalactosaminiltransferase
8.
J Autoimmun ; 146: 103235, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38696926

RESUMO

Soluble components secreted by Tfh cells are critical for the germinal center responses. In this study, we investigated whether Tfh cells could regulate the B-cell response by releasing small extracellular vesicles (sEVs). Our results showed that Tfh cells promote B-cell differentiation and antibody production through sEVs and that CD40L plays a crucial role in Tfh-sEVs function. In addition, increased Tfh-sEVs were found in mice with collagen-induced arthritis (CIA). Adoptive transfer of Tfh cells significantly exacerbated the severity of CIA; however, the effect of Tfh cells on exacerbating the CIA process was significantly diminished after inhibiting sEVs secretion. Moreover, the levels of plasma Tfh-like-sEVs and CD40L expression on Tfh-like-sEVs in RA patients were significantly higher than those in healthy subjects. In summary, Tfh cell-derived sEVs can enhance the B-cell response, and exacerbate the procession of autoimmune arthritis.


Assuntos
Artrite Experimental , Linfócitos B , Vesículas Extracelulares , Células T Auxiliares Foliculares , Animais , Artrite Experimental/imunologia , Vesículas Extracelulares/imunologia , Vesículas Extracelulares/metabolismo , Camundongos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Humanos , Células T Auxiliares Foliculares/imunologia , Masculino , Artrite Reumatoide/imunologia , Diferenciação Celular/imunologia , Ativação Linfocitária/imunologia , Transferência Adotiva , Ligante de CD40/metabolismo , Ligante de CD40/imunologia , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Índice de Gravidade de Doença , Feminino
9.
J Biomed Res ; : 1-15, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38812291

RESUMO

Most papillary thyroid carcinoma (PTC) patients have a good prognosis, but lymph node metastasis (LNM) is the most common progressive manifestation and often leads to a poor-prognosis. However, few studies focused on the underlying mechanisms of LNM. This study aimed to identity the potential role of exosomal circRNAs that contribute to LNM in PTC. We found that 9000 aberrantly expressed exosomal circRNAs in PTC patients with LNM, including 684 observably upregulation and 2193 notably downregulation. Functional enrichment analyses indicated that these aberrantly expressed circRNAs were mainly enriched in a variety of molecules and signaling pathways related to the progression and LNM of PTC. Bioinformatics analysis screened 14 circRNA-miRNA-mRNA networks associated with LNM-related signaling pathways in PTC. Moreover, circTACC2-miR-7-EGFR and circBIRC6-miR-24-3p-BCL2L11 axes were verified for potential involvement in PTC with LNM. Additionally, 4 upregulated circRNAs-related hub genes and 8 hub genes associated with downregulated circRNAs were screened, some of which were involved in LNM of PTC through verification. Collectively, our data provided a novel framework for in-depth investigation of the function of dysregulated exosomal circRNAs and their potential biomarkers in PTC patients with LNM.

10.
Biomolecules ; 14(4)2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38672418

RESUMO

The post-translational modifications (PTMs) of proteins play a crucial role in increasing the functional diversity of proteins and are associated with the pathogenesis of various diseases. This review focuses on a less explored PTM called citrullination, which involves the conversion of arginine to citrulline. This process is catalyzed by peptidyl arginine deiminases (PADs). Different members of the PAD family have distinct tissue distribution patterns and functions. Citrullination is a post-translational modification of native proteins that can alter their structure and convert them into autoantigens; thus, it mediates the occurrence of autoimmune diseases. CD4+ T cells, including Th1, Th2, and Th17 cells, are important immune cells involved in mediating autoimmune diseases, allergic reactions, and tumor immunity. PADs can induce citrullination in CD4+ T cells, suggesting a role for citrullination in CD4+ T cell subset differentiation and function. Understanding the role of citrullination in CD4+ T cells may provide insights into immune-related diseases and inflammatory processes.


Assuntos
Linfócitos T CD4-Positivos , Citrulinação , Humanos , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Animais , Doenças Autoimunes/metabolismo , Doenças Autoimunes/imunologia , Desiminases de Arginina em Proteínas/metabolismo , Processamento de Proteína Pós-Traducional , Citrulina/metabolismo , Arginina/metabolismo
12.
Clin Transl Oncol ; 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38598002

RESUMO

Indeed, tumors are a significant health concern worldwide, and understanding the underlying mechanisms of tumor development is crucial for effective prevention and treatment. Epigenetics, which refers to changes in gene expression that are not caused by alterations in the DNA sequence itself, plays a critical role in the entire process of tumor development. It goes without saying that the effect of methylation on tumors is a significant aspect of epigenetics. Among the methylation modifications, DNA methylation is an important part, which plays a regulatory role in tumor-related genes. Ten-eleven translocation 2 (TET2) is a highly influential protein involved in the modification of DNA methylation. Its primary role is associated with the suppression of tumor development, making it a significant player in cancer research. However, TET2 is frequently mentioned in hematological diseases, its role in solid tumors has received little attention. Studying the changes of TET2 in solid tumors and the regulatory mechanism will facilitate its investigation as a clinical target for targeted therapy and may also provide directions for clinical treatment of malignant tumors.

13.
Noncoding RNA Res ; 9(3): 913-920, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38638146

RESUMO

Myeloid-derived suppressor cells (MDSCs) are closely related to the occurrence and development of many cancers, but the specific mechanism is not fully understood. It has been found that N6-methyladenosine (m6A) plays a key role in RNA metabolism, but its function in MDSCs has yet to be revealed. In this study, we found that MDSCs in mice with colorectal cancer (CRC) have significantly elevated levels of m6A, while ALKBH5 expression is decreased. Overexpression of ALKBH5 can reduce the immunosuppressive function of MDSCs in vivo and in vitro, and attenuates the protumorigenic ability of MDSCs. Mechanism study found that the overexpression of ALKBH5 in MDSCs reduced the m6A modification level of Arg-1 mRNA, and then weakened the stability of Arg-1 mRNA and protein expression. These data suggest that the decreased expression of ALKBH5 in CRC tumor mice may promote the expression of Arg-1, enhance the immunosuppressor function of MDSCs, and promote tumor growth. These findings highlight that ALKBH5 may regulate the function of MDSCs in tumor-bearing mice and may be a new target for immunotherapy. This research provides a new perspective for our understanding of the role of MDSCs in cancer development, and also brings new hope for cancer treatment.

14.
Int Immunopharmacol ; 132: 111910, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38552295

RESUMO

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most prevalent forms of autoimmune encephalitis, characterized by a series of neurological and psychiatric symptoms, including cognitive impairment, seizures and psychosis. The underlying mechanism of anti-NMDAR encephalitis remains unclear. In the current study, the mouse model of anti-NMDAR encephalitis with active immunization was performed. We first uncovered excessive mitochondrial fission in the hippocampus and temporal cortex of anti-NMDAR encephalitis mice, indicated by elevated level of Phospho-DRP1 (Ser616) (p-Drp1-S616). Moreover, blockade of the autophagic flux was also demonstrated, leading to the accumulation of fragmented mitochondria, and elevated levels of mitochondrial reactive oxygen species (mtROS) and mitochondrial DNA (mtDNA) in anti-NMDAR encephalitis. More importantly, we found that the mTOR signaling pathway was overactivated, which could aggravate mitochondrial fission and inhibit autophagy, resulting in mitochondrial dysfunction. While rapamycin, the specific inhibitor of the mTOR signaling pathway, significantly alleviated mitochondrial dysfunction by inhibiting mitochondrial fission and enhancing autophagy. Levels of mtROS and mtDNA were markedly reduced after the treatment of rapamycin. In addition, rapamycin also significantly alleviated cognitive dysfunction and anxious behaviors found in anti-NMDAR encephalitis mice. Thus, our study reveals the vital role of mitochondrial dysfunction in pathological mechanism of anti-NMDAR encephalitis and lays a theoretical foundation for rapamycin to become a clinically targeted drug for anti-NMDAR encephalitis.


Assuntos
Encefalite Antirreceptor de N-Metil-D-Aspartato , Modelos Animais de Doenças , Mitocôndrias , Dinâmica Mitocondrial , Espécies Reativas de Oxigênio , Sirolimo , Serina-Treonina Quinases TOR , Animais , Encefalite Antirreceptor de N-Metil-D-Aspartato/tratamento farmacológico , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Sirolimo/uso terapêutico , Sirolimo/farmacologia , Camundongos , Serina-Treonina Quinases TOR/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Dinâmica Mitocondrial/efeitos dos fármacos , DNA Mitocondrial , Autofagia/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Feminino , Dinaminas/metabolismo , Dinaminas/genética , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/etiologia , Humanos , Camundongos Endogâmicos C57BL
16.
Phys Rev E ; 109(1-1): 014214, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38366462

RESUMO

Reservoir computing (RC) has been widely applied to predict the chaotic dynamics in many systems. Yet much broader areas related to nonsmooth dynamics have seldom been touched by the RC community which have great theoretical and practical importance. The generalization of RC to this kind of system is reported in this paper. The numerical work shows that the conventional RC with a hyperbolic tangent activation function is not able to predict the dynamics of nonsmooth systems very well, especially when reconstructing attractors (long-term prediction). A nonsmooth activation function with a piecewise nature is proposed. A kind of physics-informed RC scheme is established based on this activation function. The feasibility of this scheme has been proven by its successful application to the predictions of the short- and long-term (reconstructing chaotic attractor) dynamics of four nonsmooth systems with different complexity, including the tent map, piecewise linear map with a gap, both noninvertible and discontinuous compound circle maps, and Lozi map. The results show that RC with the new activation function is efficient and easy to run. It can make perfectly both short- and long-term predictions. The precision of reconstructing attractors depends on their complexity. This work reveals that, to make efficient predictions, the activation function of an RC approach should match the smooth or nonsmooth nature of the dynamical systems.

17.
J Mol Med (Berl) ; 102(3): 337-351, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38289385

RESUMO

N6 methyladenosine (m6A) is the most prevalent RNA epigenetic modification, regulated by methyltransferases and demethyltransferases and recognized by methylation-related reading proteins to impact mRNA splicing, translocation, stability, and translation efficiency. It significantly affects a variety of activities, including stem cell maintenance and differentiation, tumor formation, immune regulation, and metabolic disorders. Ubiquitination refers to the specific modification of target proteins by ubiquitin molecule in response to a series of enzymes. E3 ligases connect ubiquitin to target proteins and usually lead to protein degradation. On the contrary, deubiquitination induced by deubiquitinating enzymes (DUBs) can separate ubiquitin and regulate the stability of protein. Recent studies have emphasized the potential importance of ubiquitination and deubiquitination in controlling the function of m6A modification. In this review, we discuss the impact of ubiquitination and deubiquitination on m6A functional molecules in diseases, such as metabolism, cellular stress, and tumor growth.


Assuntos
Adenosina/análogos & derivados , Neoplasias , Ubiquitina-Proteína Ligases , Humanos , Ubiquitinação , Ubiquitina-Proteína Ligases/genética , Ubiquitina/genética , Proteínas/genética , Neoplasias/metabolismo
18.
Cogn Neurodyn ; 17(6): 1417-1431, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37969943

RESUMO

Brain as a dynamic system responds to stimulations with specific patterns affected by its inherent ongoing dynamics. The patterns are manifested across different levels of organization-from spiking activity of neurons to collective oscillations in local field potential (LFP) and electroencephalogram (EEG). The multilevel and multifaceted response activities show patterns seemingly distinct and non-comparable from each other, but they should be coherently related because they are generated from the same underlying neural dynamic system. A coherent understanding of the interrelationships between different levels/aspects of activity features is important for understanding the complex brain functions. Here, based on analysis of data from human EEG, monkey LFP and neuronal spiking, we demonstrated that the brain response activities from different levels of neural system are highly coherent: the external stimulus simultaneously generated event-related potentials, event-related desynchronization, and variation in neuronal spiking activities that precisely match with each other in the temporal unfolding. Based on a biologically plausible but generic network of conductance-based integrate-and-fire excitatory and inhibitory neurons with dense connections, we showed that the multiple key features can be simultaneously produced at critical dynamical regimes supported by excitation-inhibition (E-I) balance. The elucidation of the inherent coherency of various neural response activities and demonstration of a simple dynamical neural circuit system having the ability to simultaneously produce multiple features suggest the plausibility of understanding high-level brain function and cognition from elementary and generic neuronal dynamics. Supplementary Information: The online version contains supplementary material available at 10.1007/s11571-022-09889-w.

19.
Org Biomol Chem ; 21(45): 9076-9081, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37941412

RESUMO

A Hg(OTf)2-catalyzed tandem phospha-Michael addition/cyclization/dehydration of 2-hydroxychalcones with H-phosphine oxides is presented. This protocol provides a new and supplementary approach for the preparation of 4-phosphorylated 4H-chromenes in good yields (up to 99%). In addition, this domino reaction allows the successful construction of two new C-P and C-O bonds in a one-pot operation.

20.
Sensors (Basel) ; 23(20)2023 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-37896637

RESUMO

To address the issues of our agile satellites' poor attitude maneuverability, low pointing stability, and pointing inaccuracy, this paper proposes a new type of stabilized platform based on seven-degree-of-freedom Lorentz force magnetic levitation. Furthermore, in this study, we designed an adaptive controller based on the RBF neural network for the rotating magnetic bearing, which can improve the pointing accuracy of satellite loads. To begin, the advanced features of the new platform are described in comparison with the traditional electromechanical platform, and the structural characteristics and working principle of the platform are clarified. The significance of rotating magnetic bearings in improving load pointing accuracy is also clarified, and its rotor dynamics model is established to provide the input and output equations. The adaptive controller based on the RBF neural network is designed for the needs of high accuracy of the load pointing, high stability, and strong robustness of the system, and the current feedback inner loop is added to improve the system stiffness and rapidity. The final simulation results show that, when compared to the PID controller and robust sliding mode controller, the controller's pointing accuracy and anti-interference ability are greatly improved, and the system robustness is strong, which can effectively improve the pointing accuracy and pointing stability of the satellite/payload, as well as provide a powerful means of solving related problems in the fields of laser communication, high score detection, and so on.

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