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1.
Biochem Biophys Res Commun ; 718: 150078, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38735140

RESUMO

Among the environmental factors contributing to myopia, the role of correlated color temperature (CCT) of ambient light emerges as a key element warranting in-depth investigation. The choroid, a highly vascularized and dynamic structure, often undergoes thinning during the progression of myopia, though the precise mechanism remains elusive. The retinal pigment epithelium (RPE), the outermost layer of the retina, plays a pivotal role in regulating the transport of ion and fluid between the subretinal space and the choroid. A hypothesis suggests that variations in choroidal thickness (ChT) may be modulated by transepithelial fluid movement across the RPE. Our experimental results demonstrate that high CCT illumination significantly compromised the integrity of tight junctions in the RPE and disrupted chloride ion transport. This functional impairment of the RPE may lead to a reduction in fluid transfer across the RPE, consequently resulting in choroidal thinning and potentially accelerating axial elongation. Our findings provide support for the crucial role of the RPE in regulating ChT. Furthermore, we emphasize the potential hazards posed by high CCT artificial illumination on the RPE, the choroid, and refractive development, underscoring the importance of developing eye-friendly artificial light sources to aid in the prevention and control of myopia.


Assuntos
Cloretos , Corioide , Transporte de Íons , Epitélio Pigmentado da Retina , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/efeitos da radiação , Epitélio Pigmentado da Retina/patologia , Corioide/metabolismo , Corioide/efeitos da radiação , Corioide/patologia , Animais , Transporte de Íons/efeitos da radiação , Cloretos/metabolismo , Iluminação/métodos , Temperatura , Cor , Junções Íntimas/metabolismo , Miopia/metabolismo , Miopia/patologia , Miopia/etiologia
2.
J Psychiatr Res ; 175: 461-469, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38820996

RESUMO

BACKGROUND: Impaired cognition has been demonstrated in pediatric bipolar disorder (PBD). The subcortical limbic structures play a key role in PBD. However, alternations of anatomical and functional characteristics of subcortical limbic structures and their relationship with neurocognition of PBD remain unclear. METHODS: Thirty-six PBD type I (PBD-I) (15.36 ± 0.32 years old), twenty PBD type II (PBD-II) (14.80 ± 0.32 years old) and nineteen age-gender matched healthy controls (HCs) (14.16 ± 0.36 years old) were enlisted. Primarily, the volumes of the subcortical limbic structures were obtained and differences in the volumes were evaluated. Then, these structures served as seeds of regions of interest to calculate the voxel-wised functional connectivity (FC). After that, correlation analysis was completed between volumes and FC of brain regions showing significant differences and neuropsychological tests. RESULTS: Compared to HCs, both PBD-I and PBD-II patients showed a decrease in the Stroop color word test (SCWT) and digit span backward test scores. Compared with HCs, PBD-II patients exhibited a significantly increased volume of right septal nuclei, and PBD-I patients presented increased FC of right nucleus accumbens and bilateral pallidum, of right basal forebrain with right putamen and left pallidum. Both the significantly altered volumes and FC were negatively correlated with SCWT scores. SIGNIFICANCE: The study revealed the role of subcortical limbic structural and functional abnormalities on cognitive impairments in PBD patients. These may have far-reaching significance for the etiology of PBD and provide neuroimaging clues for the differential diagnosis of PBD subtypes. CONCLUSIONS: Distinctive features of neural structure and function in PBD subtypes may contribute to better comprehending the potential mechanisms of PBD.

3.
Exp Eye Res ; 244: 109946, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38815794

RESUMO

Photobiomodulation (PBM) therapy uses light of different wavelengths to treat various retinal degeneration diseases, but the potential damage to the retina caused by long-term light irradiation is still unclear. This study were designed to detect the difference between long- and short-wavelength light (650-nm red light and 450-nm blue light, 2.55 mW/cm2, reference intensity in PBM)-induced injury. In addition, a comparative study was conducted to investigate the differences in retinal light damage induced by different irradiation protocols (short periods of repeated irradiation and a long period of constant irradiation). Furthermore, the protective role of PARP-1 inhibition on the molecular mechanism of blue light-induced injury was confirmed by a gene knockdown technique or a specific inhibitor through in vitro and in vivo experiments. The results showed that the susceptibility to retinal damage caused by irradiation with long- and short-wavelength light is different. Shorter wavelength lights, such as blue light, induce more severe retinal damage, while the retina exhibits better resistance to longer wavelength lights, such as red light. In addition, repeated irradiation for short periods induces less retinal damage than constant exposure over a long period. PARP-1 plays a critical role in the molecular mechanism of blue light-induced damage in photoreceptors and retina, and inhibiting PARP-1 can significantly protect the retina against blue light damage. This study lays an experimental foundation for assessing the safety of phototherapy products and for developing target drugs to protect the retina from light damage.


Assuntos
Luz , Poli(ADP-Ribose) Polimerase-1 , Retina , Degeneração Retiniana , Animais , Poli(ADP-Ribose) Polimerase-1/metabolismo , Camundongos , Luz/efeitos adversos , Retina/efeitos da radiação , Retina/patologia , Degeneração Retiniana/etiologia , Degeneração Retiniana/metabolismo , Degeneração Retiniana/patologia , Degeneração Retiniana/prevenção & controle , Camundongos Endogâmicos C57BL , Lesões Experimentais por Radiação/patologia , Lesões Experimentais por Radiação/metabolismo , Modelos Animais de Doenças , Western Blotting , Masculino , Terapia com Luz de Baixa Intensidade , Luz Azul
4.
iScience ; 27(3): 109041, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38361626

RESUMO

Patients with neurodegenerative diseases exhibit diminished basal forebrain (BF) volume compared to healthy individuals. However, it's uncertain whether this difference is consistent between sexes. It has been reported that BF volume moderately atrophies during aging, but the effect of sex on BF volume changes during the normal aging process remains unclear. In the cross-sectional study, we observed a significant reduction in BF volume in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) compared to Healthy Controls (HCs), especially in the Ch4 subregion. Notably, significant differences in BF volume between MCI and HCs were observed solely in the female group. Additionally, we identified asymmetrical atrophy in the left and right Ch4 subregions in female patients with AD. In the longitudinal analysis, we found that aging seemed to have a minimal impact on BF volume in males. Our study highlights the importance of considering sex as a research variable in brain science.

5.
Heliyon ; 10(1): e23173, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38173490

RESUMO

Background: It is important to explore novel molecules that play a key role in esophageal cancer (ESCA) progression. Methods: Two ESCA tissue expression profile microarrays (GSE92396 and GSE17351) data from GEO were downloaded, and differentially expressed genes (DEGs) were analyzed using GEO2R. The DEGs common to both microarrays were analyzed for protein-protein interactions, KEGG and GO. The altered expression of proteasome 20S subunit α 7 (PSMA7) in ESCA tissues was analyzed using information from publicly available databases (GEO, TCGA, TNMplot). PSMA7 was overexpressed or knocked down in Eca109 and KYSE150 cells using transfection, and the effects on cell proliferation, migration, invasion and apoptosis were examined using CCK-8, Transwell, and flow cytometry experiments. Results: 284 common DEGs were identified, and 10 core proteins, HSP90AA1, AURKA, CDC6, PCNA, MCM5, KAT2B, GRB2, MYBL2, PSMA7, and CKAP5, involved in ESCA progression were identified. PSMA7 mRNA level was significantly increased in ESCA tissues. PSMA7 overexpression significantly promoted the proliferation, migration and invasion of Eca109 and KYSE150 cells, and significantly promoted apoptosis. In contrast, PSMA7 knockdown inhibited their proliferation and motility, and significantly suppressed apoptosis. Conclusion: This study analyzed multiple proteins that may play a key role in ESCA progression, and identified the pro-cancer role of PSMA7.

6.
Appl Biochem Biotechnol ; 196(3): 1211-1240, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37382790

RESUMO

Thermostability is considered a crucial parameter to evaluate the viability of enzymes in industrial applications. Over the past 31 years, many studies have been reported on the thermostability of enzymes. However, there is no systematic bibliometric analysis of publications on the thermostability of enzymes. In this study, 16,035 publications related to the thermostability of enzymes were searched and collected, showing an increasing annual trend. China contributed the most publications, while the United States had the highest citation count. International Journal of Biological Macromolecules is the most productive journal in the research field. Moreover, Chinese acad sci and Khosro Khajeh are the most active institutions and prolific authors in the field, respectively. Analysis of references with the strongest citation bursts and keyword co-occurrences, magnetic nanoparticles, metal-organic frameworks, molecular dynamics, and rational design are current hot spots and significant future research directions. This study is the first comprehensive bibliometric analysis summarizing trends and developments in enzyme thermostability research. Our findings could provide scholars with an understanding of the fundamental knowledge framework of the field and identify recent potential hotspots and research trends that could facilitate the discovery of collaboration opportunities.


Assuntos
Estruturas Metalorgânicas , Nanopartículas , Apoptose , Bibliometria , China
7.
Cereb Cortex ; 34(1)2024 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-38037843

RESUMO

Human brain structure shows heterogeneous patterns of change across adults aging and is associated with cognition. However, the relationship between cortical structural changes during aging and gene transcription signatures remains unclear. Here, using structural magnetic resonance imaging data of two separate cohorts of healthy participants from the Cambridge Centre for Aging and Neuroscience (n = 454, 18-87 years) and Dallas Lifespan Brain Study (n = 304, 20-89 years) and a transcriptome dataset, we investigated the link between cortical morphometric similarity network and brain-wide gene transcription. In two cohorts, we found reproducible morphometric similarity network change patterns of decreased morphological similarity with age in cognitive related areas (mainly located in superior frontal and temporal cortices), and increased morphological similarity in sensorimotor related areas (postcentral and lateral occipital cortices). Changes in morphometric similarity network showed significant spatial correlation with the expression of age-related genes that enriched to synaptic-related biological processes, synaptic abnormalities likely accounting for cognitive decline. Transcription changes in astrocytes, microglia, and neuronal cells interpreted most of the age-related morphometric similarity network changes, which suggest potential intervention and therapeutic targets for cognitive decline. Taken together, by linking gene transcription signatures to cortical morphometric similarity network, our findings might provide molecular and cellular substrates for cortical structural changes related to cognitive decline across adults aging.


Assuntos
Envelhecimento , Encéfalo , Adulto , Humanos , Encéfalo/fisiologia , Envelhecimento/fisiologia , Cognição/fisiologia , Lobo Temporal , Imageamento por Ressonância Magnética/métodos
8.
Cereb Cortex ; 34(1)2024 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-38031362

RESUMO

Fractal patterns have been shown to change in resting- and task-state blood oxygen level-dependent signals in bipolar disorder patients. However, fractal characteristics of brain blood oxygen level-dependent signals when responding to external emotional stimuli in pediatric bipolar disorder remain unclear. Blood oxygen level-dependent signals of 20 PBD-I patients and 17 age- and sex-matched healthy controls were extracted while performing an emotional Go-Nogo task. Neural responses relevant to the task and Hurst exponent of the blood oxygen level-dependent signals were assessed. Correlations between clinical indices and Hurst exponent were estimated. Significantly increased activations were found in regions covering the frontal lobe, parietal lobe, temporal lobe, insula, and subcortical nuclei in PBD-I patients compared to healthy controls in contrast of emotional versus neutral distractors. PBD-I patients exhibited higher Hurst exponent in regions that involved in action control, such as superior frontal gyrus, inferior frontal gyrus, inferior temporal gyrus, and insula, with Hurst exponent of frontal orbital gyrus correlated with onset age. The present study exhibited overactivation, increased self-similarity and decreased complexity in cortical regions during emotional Go-Nogo task in patients relative to healthy controls, which provides evidence of an altered emotional modulation of cognitive control in pediatric bipolar disorder patients. Hurst exponent may be a fractal biomarker of neural activity in pediatric bipolar disorder.


Assuntos
Transtorno Bipolar , Humanos , Criança , Transtorno Bipolar/diagnóstico por imagem , Transtorno Bipolar/psicologia , Encéfalo/diagnóstico por imagem , Emoções/fisiologia , Lobo Frontal , Córtex Pré-Frontal , Mapeamento Encefálico , Imageamento por Ressonância Magnética
9.
Cereb Cortex ; 34(1)2024 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-38044469

RESUMO

Brain function changes affect cognitive functions in older adults, yet the relationship between cognition and the dynamic changes of brain networks during naturalistic stimulation is not clear. Here, we recruited the young, middle-aged and older groups from the Cambridge Center for Aging and Neuroscience to investigate the relationship between dynamic metrics of brain networks and cognition using functional magnetic resonance imaging data during movie-watching. We found six reliable co-activation pattern (CAP) states of brain networks grouped into three pairs with opposite activation patterns in three age groups. Compared with young and middle-aged adults, older adults dwelled shorter time in CAP state 4 with deactivated default mode network (DMN) and activated salience, frontoparietal and dorsal-attention networks (DAN), and longer time in state 6 with deactivated DMN and activated DAN and visual network, suggesting altered dynamic interaction between DMN and other brain networks might contribute to cognitive decline in older adults. Meanwhile, older adults showed easier transfer from state 6 to state 3 (activated DMN and deactivated sensorimotor network), suggesting that the fragile antagonism between DMN and other cognitive networks might contribute to cognitive decline in older adults. Our findings provided novel insights into aberrant brain network dynamics associated with cognitive decline.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Cognição/fisiologia , Mapeamento Encefálico , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia
10.
Chinese Pharmacological Bulletin ; (12): 248-255, 2024.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-1013619

RESUMO

Aim To explore the impacts of high mobility group box 1 (HMGB1) on the phenotypes, endocy-tosis and extracellular signal-regulated kinase (ERK)/ Jun N-terminal protein kinase (JNK)/P38 mitogen-ac-tivated protein kinase (MAPK) signaling pathway in indoxyl sulfate (IS) -induced dendritic cells (DCs). Methods After treatment with 30, 300 and 600 (xmol · L

11.
J Colloid Interface Sci ; 652(Pt B): 2042-2053, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37696058

RESUMO

The all-solid-state sodium battery has emerged as a promising candidate for energy storage. However, the limited electrochemical stability of the solid electrolyte, particularly in the presence of Na metal at the anode, along with low ionic conductivity, hinders its widespread application. In this work, the design of P and O elements in Na3SbS4 solid electrolyte was investigated through a series of structural tests and characterizations. The electrochemical stability was remarkably improved in the Na/Na3SbP0.16S3.6O0.4/Na battery, exhibiting a stability of 260 h under a current of 0.1 mA cm-2. Additionally, the room temperature conductivity of Na3SbP0.16S3.6O0.4 was enhanced to 3.82 mS cm-1, maintaining a value comparable to commercial standards. The proposed design strategy provides an approach for developing sodium ion solid-state batteries with high energy density and long lifespan. The stability of the solid electrolyte interface at the Na | solid electrolyte interface proves critical for the successful assembly of all-solid-state sodium ion batteries.

12.
BMC Psychiatry ; 23(1): 515, 2023 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-37464363

RESUMO

BACKGROUND: Brain entropy reveals complexity and irregularity of brain, and it has been proven to reflect brain complexity alteration in disease states. Previous studies found that bipolar disorder adolescents showed cognitive impairment. The relationship between complexity of brain neural activity and cognition of bipolar II disorder (BD-II) adolescents remains unclear. METHODS: Nineteen BD-II patients (14.63 ±1.57 years old) and seventeen age-gender matched healthy controls (HCs) (14.18 ± 1.51 years old) were enlisted. Entropy values of all voxels of the brain in resting-state functional MRI data were calculated and differences of them between BD-II and HC groups were evaluated. After that, correlation analyses were performed between entropy values of brain regions showing significant entropy differences and clinical indices in BD-II adolescents. RESULTS: Significant differences were found in scores of immediate visual reproduction subtest (VR-I, p = 0.003) and Stroop color-word test (SCWT-1, p = 0.015; SCWT-2, p = 0.004; SCWT-3, p = 0.003) between the two groups. Compared with HCs, BD-II adolescents showed significant increased brain entropy in right parahippocampal gyrus and right inferior occipital gyrus. Besides, significant negative correlations between brain entropy values of right parahippocampal gyrus, right inferior occipital gyrus and immediate visual reproduction subtest scores were observed in BD-II adolescents. CONCLUSIONS: The findings of the present study suggested that the disrupted function of corticolimbic system is related with cognitive abnormality of BD-II adolescents. And from the perspective temporal dynamics of brain system, the current study, brain entropy may provide available evidences for understanding the underlying neural mechanism in BD-II adolescents.


Assuntos
Transtorno Bipolar , Humanos , Adolescente , Criança , Transtorno Bipolar/psicologia , Entropia , Imageamento por Ressonância Magnética , Encéfalo , Giro Para-Hipocampal/diagnóstico por imagem , Lobo Occipital/diagnóstico por imagem
13.
ACS Appl Mater Interfaces ; 15(26): 31635-31642, 2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37345989

RESUMO

Good-performing sodium solid electrolytes (SSEs) are essential for constructing all-solid-state sodium-ion batteries operating at ambient temperature. Sulfide solid electrolyte, Na3SbS4 (NBS), an excellent SSE with good chemical stability in humid air, can be synthesized with low-cost processing. However, Na3SbS4-based electrolytes with liquid-phase synthesis exhibit conductivities below milli-Siemens per centimeter. Thus, a series of halogen-doped samples formulated as Na3-xSbS4-xMx (0 ≤ x ≤ 0.3, M = Cl, Br, and I) were experimentally prepared in this study using the solid-state method to improve the battery performance. X-ray diffraction with refinement analysis and Raman spectroscopy were employed to understand deeply the connection between the crystal structure and conductivity of Na+ ions. In addition, symmetric sodium batteries with Na2.85SbS3.85Br0.15 were tested at room temperature, and pristine Na3SbS4 was used as the control group. The result showed that the symmetric sodium battery assembled with the Na2.85SbS3.85Br0.15 electrolyte can stably cycle for longer than 100 h at a current density of 0.1 mA/cm2. This research provides a method to manufacture novel SSEs by elaborating the effect of halogen doping in NBS.

14.
Dalton Trans ; 52(23): 7893-7905, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37218294

RESUMO

The fabrication of all electrolytes from noncombustible ceramic materials offers a superior option for providing safer and higher-capacity batteries to fulfill future energy needs. To achieve a competitive performance with combustible liquid electrolytes used in commercial Li-ion batteries, the creation of ceramic material compositions with a high electrical conductivity is necessary. Here, we report that co-doping with W and halogens results in a superconductivity of 13.78 mS cm-1 in a cubic-phase Na3SbS4 glass ceramic electrolyte. After undergoing high-temperature heat treatments, the W ions in the electrolyte can facilitate the replacement of S atoms with halogens, introducing many Na vacancies. The samples also had a high degree of cycling stability. An excellent glass ceramic electrolyte for Na ion batteries will be constructed for Na3SbW0.25Cl0.25S4.

15.
Cereb Cortex ; 33(13): 8645-8653, 2023 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-37143182

RESUMO

Sex differences in episodic memory (EM), remembering past events based on when and where they occurred, have been reported, but the neural mechanisms are unclear. T1-weighted images of 111 females and 61 males were acquired from the Dallas Lifespan Brain Study. Using surface-based morphometry and structural covariance (SC) analysis, we constructed structural covariance networks (SCN) based on cortical volume, and the global efficiency (Eglob) was computed to characterize network integration. The relationship between SCN and EM was examined by SC analysis among the top-n brain regions that were most relevant to EM performance. The number of SC connections (females: 3306; males: 437, P = 0.0212) and Eglob (females: 0.1845; males: 0.0417, P = 0.0408) of SCN in females were higher than those in males. The top-n brain regions with the strongest SC in females were located in auditory network, cingulo-opercular network (CON), and default mode network (DMN), and in males, they were located in frontoparietal network, CON, and DMN. These results confirmed that the Eglob of SCN in females was higher than males, sex differences in EM performance might be related to the differences in network-level integration. Our study highlights the importance of sex as a research variable in brain science.


Assuntos
Memória Episódica , Humanos , Masculino , Feminino , Caracteres Sexuais , Encéfalo , Imageamento por Ressonância Magnética , Mapeamento Encefálico
16.
Cereb Cortex ; 33(12): 7540-7552, 2023 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-36928535

RESUMO

Bipolar disorder (BD) is a heritable psychiatric disorder with a complex etiology that is often associated with cortical alterations. Morphometric studies in adults with BD are well established; however, few have examined cortical changes in pediatric BD (PBD). Additionally, the correlation between cortical thickness (CT) changes in PBD and gene expression remains elusive. Here, we performed an integrative analysis using neuroimaging data from 58 PBD individuals and the Allen human brain transcriptomic dataset. We applied partial least squares (PLS) regression analysis on structural MRI data and cortical gene expression, enrichment and specific cell type analysis to investigate the genetic correlates of CT alterations in PBD. We found the expression levels of PBD-related genes showed significant spatial correlations with CT differences. Further enrichment and specific cell type analysis revealed that transcriptome signatures associated with cortical thinning were enriched in synaptic signaling, ion channels, astrocytes, and excitatory neurons. Neurodevelopmental patterns of these genes showed significantly increased expression in the cerebellum, cortex, and subcortical regions during the adolescence period. These results highlight neurodevelopmental transcriptional changes could account for most of the observed correlations with CT differences in PBD, which offers a novel perspective to understand biological conceptualization mechanisms for the genetic correlates of CT alterations.


Assuntos
Transtorno Bipolar , Adulto , Adolescente , Humanos , Criança , Transtorno Bipolar/diagnóstico por imagem , Transtorno Bipolar/genética , Transtorno Bipolar/psicologia , Transcriptoma , Astrócitos , Encéfalo , Imageamento por Ressonância Magnética , Neurônios
17.
ACS Appl Mater Interfaces ; 15(1): 1392-1400, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36583680

RESUMO

Chalcogenide solid-state electrolytes (SEs) have been regarded as promising candidates for lithium dendrite suppression due to their high ionic conductivity, suitable mechanical strength, and large Li+ ion transference number. However, the wide applications of SEs in pragmatic all-solid-state batteries are still retarded by their limited interface stability, which leads to lithium dendrite growth and formation of interphase with high resistance. In addition, the interphase evolution mechanism between SEs and metallic Li anodes remains unclear. Herein, this work demonstrates that the interfacial stability of Li2S-SiS2-P2S5 SEs can be effectively enhanced by tuning the interphase through LiI incorporation. This strategy contributes to a high ionic conductivity of the SEs and electronic insulation interphase containing LiI. Thus, the 70(60Li2S-28SiS2-12P2S5)-30 LiI SEs prepared by melt-quenching exhibit a high ionic conductivity of 1.74 mS cm-1 at room temperature and a larger critical current density of 1.65 mA cm-2 at 65 °C. The cycling life of the symmetric Li|SEs|Li cell is up to 200 h without significant resistance growth at 0.1 mA cm-2 at room temperature. This enhanced interface stability is revealed to originate from the in situ-formed LiI within the interphase, which prevents continual SEs degradation and suppresses lithium dendrite growth. This work provides a vital understanding of interphase evolution, which is valuable for designing SEs with long cycling stability.

18.
Neural Netw ; 159: 125-136, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36565690

RESUMO

Artificial neural networks (ANNs) have been widely adopted as general computational tools both in computer science as well as many other engineering fields. Stochastic gradient descent (SGD) and adaptive methods such as Adam are popular as robust optimization algorithms used to train the ANNs. However, the effectiveness of these algorithms is limited because they calculate a search direction based on a first-order gradient. Although higher-order gradient methods such as Newton's method have been proposed, they require the Hessian matrix to be semi-definite, and its inversion incurs a high computational cost. Therefore, in this paper, we propose a variable three-term conjugate gradient (VTTCG) method that approximates the Hessian matrix to enhance search direction and uses a variable step size to achieve improved convergence stability. To evaluate the performance of the VTTCG method, we train different ANNs on benchmark image classification and generation datasets. We also conduct a similar experiment in which a grasp generation and selection convolutional neural network (GGS-CNN) is trained to perform intelligent robotic grasping. After considering a simulated environment, we also test the GGS-CNN with a physical grasping robot. The experimental results show that the performance of the VTTCG method is superior to that of four conventional methods, including SGD, Adam, AMSGrad, and AdaBelief.


Assuntos
Redes Neurais de Computação , Robótica , Algoritmos , Benchmarking
19.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-984245

RESUMO

Background The converter stations of high-voltage direct current (HVDC) transmission lines generate special total electric fields. At present, few investigations have been conducted on total electric fields in the workplace of converter stations from an perspective of occupational health. Objective To understand the current situation of total electric field strength in the workplace of converter stations. Methods Using purposive sampling, a calibrated HDEM-1 direct current (DC) total electric field strength measurement system was used to measure the total electric fields of 12 converter stations serving 6 DC lines in Southeast and Southwest China according to the Measurement method for total electric field strength and ion current density of the converter stations and DC transmission lines (DL/T 1089—2008). The results were evaluated according to occupational exposure limits recommended by The limits of electromagnetic environment at ±800 kV UHV DC converter station (DL/T 275—2012), the American Conference of Governmental Industrial Hygienists (ACGIH), and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Results A total of 615 check points were planned, the total electric field strength was 0.05-37.05 kV·m−1, and the median was 10.45 kV·m−1. The total electric field strength of 39 check points (6.3%) exceeded 25 kV·m−1 (the limits of ACGIH and ICNIRP), and the total electric field strength of 12 check points (2.0%) exceeded 30 kV·m−1 (the limit of DL/T 275—2012). There were statistically significant differences in the total electric field strength values and the proportions of exceeding 25 kV·m−1 between the neutral regions and the positive regions and between the neutral regions and the negative regions (P < 0.01). The proportion of total electric field strength exceeding 30 kV·m−1 in the negative regions was higher than that in the positive regions (P < 0.01). There were no significant differences in the total electric field strength of converter stations at different voltage levels and different altitudes (P > 0.05). There were no significant differences in the proportions of total electric field exceeding 25 kV·m−1 and exceeding 30 kV·m−1 in converter stations at different voltage levels and different altitudes (P > 0.05). Conclusion The total electric field in some workplace of converter stations exceeds selected limits. Converter station operators may be exposed to high-strength total electric field for a short time.

20.
Front Neurosci ; 16: 984571, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36213738

RESUMO

An increasing number of studies have shown that the functional interactions between the thalamus and cerebral cortices play an important role in cognitive function and are influenced by age. Previous studies have revealed age-related changes in the thalamo-cortical system within individuals, while neglecting differences between individuals. Here, we characterized inter-subject functional correlation (ISFC) between the thalamus and several cortical brain networks in 500 healthy participants aged 18-87 years old from the Cambridge Centre for Aging and Neuroscience (Cam-CAN) cohort using movie-watching state fMRI data. General linear models (GLM) were performed to assess age-related changes in ISFC of thalamo-cortical networks and the relationship between ISFC and fluid intelligence. We found significant age-related decreases in ISFC between the posterior thalamus (e.g., ventral posterior nucleus and pulvinar) and the attentional network, sensorimotor network, and visual network (FDR correction with p < 0.05). Meanwhile, the ISFC between the thalamus (mainly the mediodorsal nucleus and ventral thalamic nuclei) and higher-order cortical networks, including the default mode network, salience network and control network, showed complex changes with age. Furthermore, the altered ISFC of thalamo-cortical networks was positively correlated with decreased fluid intelligence (FDR correction with p < 0.05). Overall, our results provide further evidence that alterations in the functional integrity of the thalamo-cortical system might play an important role in cognitive decline during aging.

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